title: Minimal-invasive enhancement of auditory perception by terahertz wave modulation

abstract: Hearing impairment is a common disease affecting a substantial proportion of the global population. Currently, the most effective clinical treatment for patients with sensorineural deafness is to implant an artificial electronic cochlea. However, the improvements to hearing perception are variable and limited among healthy subjects. Moreover, cochlear implants have disadvantages, such as crosstalk derived from the currents that spread into non-target tissue between the electrodes. Here, in this work, we describe terahertz wave modulation (THM), a new, minimally invasive technology that can enhance hearing perception in animals by reversible modulation of currents in cochlear hair cells. Using single-cell electrophysiology, guinea pig audiometry, and molecular dynamics simulations (MD), we show that THM can reversibly increase mechano-electrical transducer (MET) currents ([~]50% higher) and voltage-gated K+ currents in cochlear hair cells through collective resonance of -C=O groups. In addition, measurement of auditory brainstem response (ABR) in guinea pigs treated with THM indicated a [~]10 times increase in hearing sensitivity. This study thus reports a new method of highly spatially selective hearing enhancement without introducing any exogeneous gene, which has potential applications for treatment of hearing disorders as well as several other areas of neuroscience.


title: Genome-wide cis-decoding for expression designing in tomato using cistrome data and explainable deep learning

abstract: In the evolutionary paths of plants, variations of the cis-regulatory elements (CREs) resulting in expression diversification have played a central role in driving the establishment of lineage-specific traits. However, it is difficult to predict expression behaviors from the CRE patterns to properly harness them, mainly because the biological processes are complex. In this study, we used cistrome datasets and explainable convolutional neural network (CNN) frameworks to predict genome-wide expression patterns in tomato fruits from the DNA sequences in gene regulatory regions. By fixing the effects of trans-elements using single cell-type spatiotemporal transcriptome data for the response variables, we developed a prediction model of a key expression pattern for the initiation of tomato fruit ripening. Feature visualization of the CNNs identified nucleotide residues critical to the objective expression pattern in each gene and their effects, were validated experimentally in ripening tomato fruits. This cis-decoding framework will not only contribute to understanding the regulatory networks derived from CREs and transcription factor interactions, but also provide a flexible way of designing alleles with optimized expression.

category: plant biology


title: Heterogeneity and molecular programming of progenitors for motor neurons and oligodendrocytes

abstract: The pMN domain is a restricted domain in the ventral spinal cords, defined by the expression of olig2 gene. The fate determination of pMN progenitors is highly temporally and spatially regulated, with motor neurons and oligodendrocyte progenitor cells (OPCs) developing sequentially. Insight into the heterogeneity and molecular programs of pMN progenitors is currently lacking. With the zebrafish model, we identified multiple states of neural progenitors using single-cell sequencing: proliferating progenitors, common progenitors for both motor neurons and OPCs, and restricted precursors for either motor neurons or OPCs. We found specific molecular programs for neural progenitor fate transition, and manipulations of representative genes in the motor neuron or OPC lineage confirmed their critical role in cell fate determination. The transcription factor NPAS3 is necessary for the development of the OPC lineage and can interact with many known genes associated with schizophrenia. Deciphering progenitor heterogeneity and molecular mechanisms for these transitions will elucidate the formation of complex neuron-glia networks in the central nervous system during development, and understand the basis of neurodevelopmental disorders.

category: neuroscience


title: Dissociating the neural correlates of subjective visibility from those of decision confidence

abstract:
A key goal of consciousness science is identifying neural signatures of being aware vs. unaware of simple stimuli. This is often investigated in the context of near-threshold detection, with reports of stimulus awareness being linked to heightened activation in a frontoparietal network. However, due to reports of stimulus presence typically being associated with higher confidence than reports of stimulus absence, these results could be explained by frontoparietal regions encoding stimulus visibility, decision confidence or both. In an exploratory analysis, we leverage fMRI data from 35 human participants (20 females) to disentangle these possibilities. We first show that, whereas stimulus identity was best decoded from the visual cortex, stimulus visibility (presence vs. absence) was best decoded from prefrontal regions. To control for effects of confidence, we then selectively sampled trials prior to decoding to equalize confidence distributions between absence and presence responses. This analysis revealed striking differences in the neural correlates of subjective visibility in prefrontal cortex regions of interest, depending on whether or not differences in confidence were controlled for. We interpret our findings as highlighting the importance of controlling for metacognitive aspects of the decision process in the search for neural correlates of visual awareness.

Significance statementWhile much has been learned over the past two decades about the neural basis of visual awareness, the role of the prefrontal cortex remains a topic of debate. By applying decoding analyses to functional brain imaging data, we show that prefrontal representations of subjective visibility are contaminated by neural correlates of decision confidence. We propose a new analysis method to control for these metacognitive aspects of awareness reports, and use it to reveal confidence-independent correlates of perceptual judgments in a subset of prefrontal areas.


title: Phylogenomic insights into biogeographic diversification and character evolution of the Sino-Japanese disjunctive Diabelia (Caprifoliaceae)

abstract: Understanding biological diversity and the mechanisms of the Sino-Japanese disjunctions are major challenges in eastern Asia biogeography. The Sino-Japanese flora has been broadly studied as an ideal model for plant phylogeography. Diabelia (Caprifoliaceae) is an East Asian genus, with a disjunctive distribution across the Sino-Japanese region. However, relationships within Diabelia remain elusive. In this study, we reconstructed the phylogeny of Diabelia and inferred historical biogeography and evolutionary patterns based on nuclear and plastid sequences from target enrichment and genome skimming approaches, respectively. We found that the main clades within Diabelia were discordant between nuclear and plastid trees. Both nuclear and plastid phylogenetic analyses supported five main clades: D. serrata, D. tetrasepala, D. sanguinea, D. spathulata var. stenophylla and D. spathulata var. spathulata. Species network analyses revealed that Diabelia tetrasepala is likely the result of a hybridization event. Divergence time estimation and ancestral area reconstructions showed that Diabelia originated in Japan during the early Miocene, with subsequent vicariance and dispersal events between Japan and Korea, and between Japan and China. Overall, our results support the division of Diabelia into five main clades and the recognition of five species in the genus. This research provides new insights in the species delimitation and speciation processes of taxonomically complex lineages such as Diabelia.

category: evolutionary biology


title: Nuclear and plastid phylogenomic analyses provide insights into the biogeography and reticulate evolution of the Sino-Japanese disjunctive Diabelia (Caprifoliaceae)


title: Nuclear and plastid phylogenomic analyses provide insights into the reticulate evolution, species delimitation and biogeography of the Sino-Japanese disjunctive Diabelia (Caprifoliaceae)


title: Song preferences predict the quality of vocal learning in zebra finches

abstract: In songbirds, learning to sing is a highly social process that likely involves social reward. Here, we hypothesized that the degree to which a juvenile songbird learns a song depends on the degree to which it finds that song rewarding to hear during vocal development. We tested this hypothesis by measuring song preferences in young birds during song learning and then analyzing their adult songs. Song preferences were measured in an operant key-pressing assay. Juvenile male zebra finches (Taeniopygia guttata) had access to two keys, each of which was associated with a higher likelihood of playing the song of their father or that of another familiar adult ("neighbor"). To minimize the effects of exposure on learning, we implemented a reinforcement schedule that allowed us to detect preferences while balancing exposure to each song. On average, the juveniles significantly preferred the fathers song early during song learning, before they were themselves singing. At around post-hatch day 60, their preference shifted to the neighbors song. At the end of the song learning period, we recorded the juveniles songs and compared them to the fathers and the neighbors song. All of the birds copied fathers song. The accuracy with which the fathers song was imitated was positively correlated with the peak strength of the preference for the fathers song during the sensitive period. Our results show that preference for a social stimulus, in this case a vocalization, predicted social learning during development.

category: animal behavior and cognition


title: Tracking-based rolling angles recovery method for holographic tomography of flowing cells

abstract: Holographic Tomography (HT) is an emerging label-free technique for microscopic bioimaging applications, that allows reconstructing the three-dimensional (3D) refractive index (RI) distribution of biological specimens. Recently, an in-flow HT technique has been proposed in which multiple digital holograms are recorded at different viewing angles around the sample while it flows and rotates within a microfluidic channel. However, unlike conventional HT methods, there is no a priori information about cell 3D orientations, that are instead requested to perform any tomographic algorithm. Here we investigate a tracking-based rolling angles recovery method, showing robustness against the samples features. It is based on a phase images similarity metric recently demonstrated, that exploits the local contrast phase measurements to recognize a full cell rotation within the microfluidic channel. Hence, the orientations of the flowing cells are retrieved from their positions, which are in turn computed through the 3D holographic tracking. The performances of the rolling angles recovery method have been assessed both numerically, by simulating a 3D cell phantom, and experimentally, by reconstructing the 3D RI tomograms of two cancer cells. Both the numerical and the experimental analysis have been performed at different spatial resolutions. This rolling angles recovery method, not depending on the cell shapes, the RI contents, and the optical experimental conditions, could pave the way to the study of circulating tumor cells (CTCs) in the challenging tool of liquid biopsy.

category: bioengineering


title: SynergyFinder Plus: towards a better interpretation and annotation of drug combination screening datasets

abstract: Combinatorial therapies have been recently proposed to improve the efficacy of anticancer treatment. The SynergyFinder R package is a software used to analyze pre-clinical drug combination datasets. Here, we report the major updates to the SynergyFinder R package for improved interpretation and annotation of drug combination screening results. Unlike the existing implementations, the updated SynergyFinder R package includes five main innovations. (1) We extend the mathematical models to higher-order drug combination data analysis and implement dimension reduction techniques for visualizing the synergy landscape. (2) We provide a statistical analysis of drug combination synergy and sensitivity with confidence intervals and P values. (3) We incorporate a synergy barometer to harmonize multiple synergy scoring methods to provide a consensus metric for synergy. (4) We evaluate drug combination synergy and sensitivity to provide an unbiased interpretation of the clinical potential. (5) We enable fast annotation of drugs and cell lines, including their chemical and target information. These annotations will improve the interpretation of the mechanisms of action of drug combinations. To facilitate the use of the R package within the drug discovery community, we also provide a web server at www.synergyfinderplus.org as a user-friendly interface to enable a more flexible and versatile analysis of drug combination data.

category: bioinformatics


title: SynergyFinder Plus: Toward Better Interpretation and Annotation of Drug Combination Screening Datasets


title: Integrated Multi-Omics Data Reveals the Molecular Subtypes of Prostate Cancer

abstract: Prostate cancer (PCa), the second most common male malignancy, is the fifth leading cause of cancer-related death and places notable burdens on medical resources. Most of the previous subtypes only focused on one or fewer types of data or ignored the genomic heterogeneity among PCa patients with diverse genetic backgrounds. Therefore, it is essential to precisely identify the specific molecular features and judge potential clinical outcomes based on multi-omics data. In the current study, we first identified the PCa multi-omics classification (PMOC) system based on the multi-omics, including mRNA, miRNA, lncRNA, DNA methylation, and gene mutation, using a total of ten state-of-the-art clustering algorithms. The PMOC1 subtype, also called the inflammatory subtype, contains the highest expression levels of immune checkpoint proteins, moderate activated immune-associated pathways. The PMOC2 tumor-activated subtype demonstrated the worst prognosis, which might be impacted by the activated cell cycle and DNA repair pathways, and also characterized by the most genetic alterations of mutant TP53, mutant APC and copy number alteration of 8q24.21 region. The PMOC3 subtype is likely to be a balance subtype, with the activated oncogenic signaling pathways, including hypoxia, angiogenesis, epithelial mesenchymal transition, and PI3K/AKT pathways. As well as with the activated proinflammatory pathways, including IL6/JAK/STAT3, IL2/STAT5, Notch and TNF- signaling. Additionally, PMOC3 subtype also linked with the activation of the androgen response and the high response rate of ARSI treatment. Taken together, we defined the PMOC system for PCa patients via multi-omics data and consensus results of ten algorithms, this multi-omics consensus PCa molecular classification can further assist in the precise clinical treatment and development of targeted therapy.

category: cancer biology


title: Stat3 co-operates with mutant Ezh2Y641F to regulate gene expression and limit the anti-tumor immune response in melanoma

abstract: One of the most frequently genetically altered chromatin modifiers in melanoma is the Enhancer of Zeste Homolog 2 (EZH2), the catalytic component of the Polycomb Repressive Complex 2 (PRC2), which methylates lysine 27 on histone 3 (H3K27me3), a chromatin mark associated with transcriptional repression. Genetic alterations in EZH2 in melanoma include amplifications and activating point mutations at tyrosine 641 (Y641). The oncogenic role of EZH2 in melanoma has previously been identified; however, its downstream mechanisms remain underexplored. We found that in genetically engineered mouse models, Ezh2Y641F expression causes upregulation of a subset of interferon-regulated genes in melanoma cells, suggesting a potential role of the immune system in the pathogenesis of these mutations. Upregulation of these interferon genes was not a result of changes in H3K27me3, but through a direct and non-canonical interaction between Ezh2 and Signal Transducer and Activator of Transcription 3 (Stat3). Ezh2 directly binds Stat3, and, in the presence of Ezh2Y641F, Stat3 protein is hypermethylated. Expression of Stat3 was required to maintain an anti-tumor immune response and its depletion resulted in faster melanoma progression and disease recurrence. Molecularly, Stat3 and Ezh2 bind together at many genomic loci, and can both activate and repress gene expression in association with the rest of the PRC2 complex. These results suggest that Ezh2 can mediate melanomagenesis through evasion of the anti-tumor immune response, and that the immunomodulatory properties of Stat3 are context dependent.


title: The liverwort Marchantia polymorpha operates a depolarization-activated Slowpoke (SLO) K+ channel that recognises pH changes in the environment

abstract: Voltage-dependent ion channels are a prerequisite for cellular excitability and electrical communication - important traits for multicellular organisms to thrive in a changeable terrestrial environment. Based on their presence in extant embryophytes and closely-related green algae, the first plants to survive on land likely possessed genes encoding channels with homology to large-conductance calcium-activated K+ channels (BK channels from the Slo family) in addition to primary voltage-gated potassium channels from the plant VG-type family (Shaker or Kv channels). While the function and gating of Shaker channels has been characterised in flowering plants, so far knowledge of BK channels has been limited to animal models. In humans, BK-mediated K+ efflux has a critical role in sperm motility and membrane polarisation to enable fertilisation. In the liverwort Marchantia polymorpha, the MpBK2a channel gene is most highly expressed in male reproductive tissue, suggesting that these channels may function in sexual reproduction. We characterised MpBK2a channels and found them to be strongly K+-selective, outward-rectifying, 80-pS channels capable of repolarising the membrane after stimulus-dependent depolarisation. In contrast to its animal counterpart, MpBK2a is insensitive to cytoplasmic Ca2+ variations but effectively gated by pH changes. Given that this plant BK channel is active even in the presence of trace amounts of external K+ and at low pH, the liverwort channel could have stabilised the membrane potential under stressful pre-historic conditions including nutrient-depleted and acid environments as early plant pioneers conquered land.


title: High-throughput discovery of peptide activators of a bacterial sensor kinase

abstract: Bacteria use two-component system (TCS) signaling pathways to sense and respond to peptides involved in host defense, quorum sensing, and inter-bacterial warfare. However, little is known about the peptide-sensing capabilities of these TCSs. Here, we develop a high-throughput E. coli display method to characterize the effects of human antimicrobial peptides (AMPs) on the pathogenesis-regulating TCS PhoPQ of Salmonella Typhimurium. We find that PhoPQ senses AMPs comprising diverse sequences, structures, and biological functions. Using thousands of AMP variants, we identify sub-domains and biophysical features responsible for PhoPQ activation. We show that most of the newfound activators induce PhoPQ in S. Typhimurium, suggesting a role in virulence regulation. Finally, we find that PhoPQ homologs from Klebsiella pneumoniae and extraintestinal pathogenic E. coli, which occupy different in vivo niches, exhibit distinct AMP response profiles. Our high-throughput method enables new insights into the specificities, mechanisms, and evolutionary dynamics of TCS-mediated peptide sensing in bacteria.

category: synthetic biology


title: Test-retest reliability of regression dynamic causal modeling

abstract:
AO_SCPLOWBSTRACTC_SCPLOWRegression dynamic causal modeling (rDCM) is a novel and computationally highly efficient method for inferring effective connectivity at the whole-brain level. While face and construct validity of rDCM have already been demonstrated, here we assessed its test-retest reliability - a test-theoretical property of particular importance for clinical applications - together with group-level consistency of connection-specific estimates and consistency of whole-brain connectivity patterns over sessions. Using the Human Connectome Project (HCP) dataset for eight different paradigms (tasks and rest) and two different parcellation schemes, we found that rDCM provided highly consistent connectivity estimates at the group level across sessions. Second, while test-retest reliability was limited when averaging over all connections (range of mean ICC 0.24-0.42 over tasks), reliability increased with connection strength, with stronger connections showing good to excellent test-retest reliability. Third, whole-brain connectivity patterns by rDCM allowed for identifying individual participants with high (and in some cases perfect) accuracy. Comparing the test-retest reliability of rDCM connectivity estimates to measures of functional connectivity, rDCM performed favorably - particularly when focusing on strong connections. Generally, for all methods and metrics, task-based connectivity estimates showed greater reliability than those from the resting state. Our results underscore the potential of rDCM for human connectomics and clinical applications.

AO_SCPLOWUTHORC_SCPLOW SO_SCPLOWUMMARYC_SCPLOWTest-retest reliability is an important prerequisite for the validity of connectivity estimates in many situations, particularly in clinical applications. Here, using different datasets from the Human Connectome Project, we demonstrate that regression DCM (rDCM) yields good to excellent test-retest reliability when focusing on strong connections. Comparing this to the test-retest reliability of functional connectivity measures, rDCM performed favorably in most cases. Furthermore, we show that reliability is not homogeneously distributed: we identified several regions (primarily in frontal and temporal lobe) that were linked via highly-reliable connections, regardless of the paradigm. Finally, we demonstrate that individual connectivity profiles are sufficiently unique that participants can be identified with high accuracy. Our findings emphasize the potential of rDCM for robust inference on directed "connectivity fingerprints" from fMRI data.


title: Brief exposure of neuronal cells to levels of short chain fatty acids observed in human systemic circulation impair the cell lipid metabolism resulting in associated cell death by apoptosis

abstract: Communication between gut microbiota and the brain is an enigma. Alterations in the gut microbial community affects enteric metabolite levels, such as SCFAs. SCFAs have been proposed as a possible mechanism through which the gut microbiome modulate brain health and function. This study analyzed for the first time the effects of SCFAs at levels reported in human systemic circulation on human neuronal cell energy metabolism, viability, survival and the brain lipidome. Cell and rat brain lipidomics was done using UHPLC-HESI-HRAMS/MS. Neuronal cells viability, survival and energy metabolism were analyzed via flow cytometer, immunofluorescence, and SeahorseXF platform. Lipidomics analysis demonstrated that SCFAs significantly remodeled the brain lipidome in vivo and in vitro. The most notable remodulation was observed in the metabolism of phosphatidylethanolamine plasmalogens, and mitochondrial lipids carnitine and cardiolipin. Increased mitochondrial mass, fragmentation, and hyperfusion occurred concomitant with the altered mitochondrial lipid metabolism resulting in decreased neuronal cell respiration, ATP production, and increased cell death. This suggests SCFAs at levels observed in human systemic circulation can adversely alter the brain lipidome and neuronal cell function potentially negatively impacting brain health outcomes.


title: Prepubertal ovariectomy alters dorsomedial striatum indirect pathway neuron excitability and explore/exploit balance in female mice

abstract: Decision-making circuits are modulated across life stages (e.g. juvenile, adolescent, or adult)--as well as on the shorter timescale of reproductive cycles in females--to meet changing environmental and physiological demands. Ovarian hormonal modulation of relevant neural circuits is a potential mechanism by which behavioral flexibility is regulated in females. Here we examined the influence of prepubertal ovariectomy (pOVX) versus sham surgery on performance in an odor-based multiple choice reversal task. We observed that pOVX females made different types of errors during reversal learning compared to sham surgery controls. Using reinforcement learning models fit to trial-by-trial behavior, we found that pOVX females exhibited lower inverse temperature parameter ({beta}) compared to sham females. These findings suggest that OVX females solve the reversal task using a more exploratory choice policy, whereas sham females use a more exploitative policy prioritizing estimated high value options. To seek a neural correlate of this behavioral difference, we performed whole-cell patch clamp recordings within the dorsomedial striatum (DMS), a region implicated in regulating action selection and explore/exploit choice policy. We found that the intrinsic excitability of dopamine receptor type 2 (D2R) expressing indirect pathway spiny projection neurons (iSPNs) was significantly higher in pOVX females compared to both unmanipulated and sham surgery females. Finally, to test whether mimicking this increase in iSPN excitability could recapitulate the pattern of reversal task behavior observed in pOVX females, we chemogenetically activated DMS D2R(+) neurons within intact female mice. We found that chemogenetic activation increased exploratory choice during reversal, similar to the pattern we observed in pOVX females. Together, these data suggest that pubertal status may influence explore/exploit balance in females via the modulation of iSPN intrinsic excitability within the DMS.


title: Arousal-dependent auditory response in the brain of Bengalese finches as measured by gene expression

abstract: Songbirds use auditory feedback to maintain their own songs. Juveniles also memorize a tutor song and use memory as a template to make up their own songs through auditory feedback. A recent electrophysiological study revealed that HVC neurons respond to BOS playback only in low arousal, sleeping, or anesthetized conditions. One outstanding question is how does auditory suppression occur in the brain? Here, we determined how arousal affects auditory responses simultaneously in the whole brain and over the song neural circuit in Bengalese finches, using the immediate early gene egr-1 as a marker of neural activity. Our results showed that auditory responses in the low-arousal state were less susceptible to gating, which was also confirmed by gene expression, and that the suppression may be weaker than observed in previous zebra finch studies. This may be because the Bengalese finch is a domesticated species. In addition, our results suggest that information may flow from the MLd.I of the midbrain to higher auditory regions. Altogether, this study presents a new attempt to explore the auditory suppression network by simultaneously investigating the whole brain using molecular biology methods.


title: Spatial and temporal autocorrelation weave human brain networks

abstract: High-throughput experimental methods in neuroscience have led to an explosion of techniques for measuring complex interactions and multi-dimensional patterns. However, whether sophisticated measures of emergent phenomena can be traced back to simpler low-dimensional statistics is largely unknown. To explore this question, we examine resting state fMRI (rs-fMRI) data using complex topology measures from network neuroscience. We show that spatial and temporal autocorrelation are reliable statistics which explain numerous measures of network topology. Surrogate timeseries with subject-matched spatial and temporal autocorrelation capture nearly all reliable individual and regional variation in these topology measures. Network topology changes during aging are driven by spatial autocorrelation, and multiple serotonergic drugs causally induce the same topographic change in temporal autocorrelation. This reductionistic interpretation of widely-used complexity measures may help link them to neurobiology.


title: Spatial and temporal autocorrelation weave complexity in brain networks


title: Attention Networks and the Intrinsic Network Structure of the Human Brain

abstract:
Attention network theory states that attention is not a unified construct but consists of three independent systems that are supported by separable distributed networks: an alerting network to deploy attentional resources in anticipation of upcoming events, an orienting network to direct attention to a cued location, and a control network to select relevant information at the expense of concurrently available information. Ample behavioral and neuroimaging evidence supports the dissociation of the three attention domains. The strong assumption that each attentional system is realized through a separable network, however, raises the question how these networks relate to the intrinsic network structure of the brain.

Our understanding of brain networks has advanced majorly in the past years due to the increasing focus on brain connectivity. It is well established that the brain is intrinsically organized into several large-scale networks whose modular structure persists across task states. Existing proposals on how the presumed attention networks relate to intrinsic networks rely mostly on anecdotal and partly contradictory arguments. We addressed this issue by mapping different attention networks with highest spatial precision at the level of cifti-grayordinates. Resulting group maps were compared to the group-level topology of 23 intrinsic networks which we reconstructed from the same participants resting state fMRI data. We found that all attention domains recruited multiple and partly overlapping intrinsic networks and converged in the dorsal fronto-parietal and midcingulo-insular network. While we observed a preference of each attentional domain for its own set of intrinsic networks, implicated networks did not match well to those proposed in the literature. Our results indicate a necessary refinement of the attention network theory.


title: Gene Expression Associated with Individual Variability in Intrinsic Functional Connectivity

abstract: It has been revealed that intersubject variability (ISV) in intrinsic functional connectivity (FC) is associated with a wide variety of cognitive and behavioral performances. However, the underlying organizational principle of ISV in FC and its related gene transcriptional profiles remain unclear. Using resting-state fMRI data from the Human Connectome Project (299 participants) and microarray gene expression data from the Allen Human Brain Atlas, we conducted a transcription-neuroimaging association study to investigate the spatial configurations of ISV in intrinsic FC and their associations with gene transcriptional profiles. We found that the multimodal association cortices showed the greatest ISV in FC, while the unimodal cortices and subcortical areas showed the least ISV. Importantly, partial least squares regression analysis revealed that the transcriptional profiles of genes associated with human accelerated regions (HARs) could explain 31.29% of the variation in the spatial distribution of ISV in FC. The top-related genes in the transcriptional profiles were enriched for the development of the central nervous system, neurogenesis and the cellular components of synapse. Moreover, we observed that the effect of gene expression profile on the heterogeneous distribution of ISV in FC was significantly mediated by the cerebral blood flow configuration. These findings highlighted the spatial arrangement of ISV in FC and their coupling with variations in transcriptional profiles and cerebral blood flow supply.


title: Discovery, diversity and functional associations of crAss-like phages in human gut metagenomes from four Dutch cohorts

abstract:
The crAss-like phages are a diverse group of related viruses that includes one of the most abundant viruses of the human gut. To explore their diversity and functional role in human population and clinical cohorts, we analyzed gut metagenomic data collected from more than 2000 individuals from the Netherlands. We discovered 125 novel species-level and 32 novel genus-level clusters of crAss-like phages, all belonging to five previously recognized groups associated with the human gut. Analysis of their genomic features revealed that closely related crAss-like phages can possess strikingly divergent regions responsible for transcription, presumably acquired through recombination. Prediction of crAss-like phage hosts pointed primarily to bacteria of the phylum Bacteroidetes, consistent with previous reports. Finally, we explored the temporal stability of crAss-like phages over a 4-year period and identified associations between the abundance of crAss-like phages and several human phenotypes, including depletion of crAss-like phages in inflammatory bowel disease patients.

HighlightsO_LI125 tentative new species of crAss-like phages were discovered
C_LIO_LIClosely related crAss-like phages often possess highly divergent transcription gene modules possibly acquired via recombination
C_LIO_LICrAss-like fraction of the human gut virome remains relatively stable over the period of 4 years
C_LIO_LIPrevalence of crAss-like phages in the human gut is associated with several metabolic, dietary and health phenotypes
C_LIO_LIGut crAss-like phages are depleted in inflammatory bowel disease patients
C_LI

category: microbiology


title: High-quality complete genome resource of plant pathogenic bacterium Pectobacterium atrosepticum strain Green1 isolated from potato (Solanum tuberosum L.) in Greenland

abstract: Pectobacterium atrosepticum is a narrow host range pectinolytic plant pathogenic bacterium causing blackleg of potato (Solanum tuberosum L.) worldwide. Till present, several P. atrosepticum genomes have been sequenced and characterized in detail; all of these genomes have come, however, from P. atrosepticum strains isolates from plants grown in temperate zones, not from hosts cultivated under different climatic conditions. Herewith, we present the first complete, high-quality genome of the P. atrosepticum strain Green1 isolated from potato plants grown under subarctic climate in Greenland. The genome of P. atrosepticum strain Green1 consists of one chromosome of 4,959,719 bp., with a GC content of 51% and no plasmids. The genome contains 4531 annotated features, including 4179 protein-coding genes (CDSs), 22 rRNA genes, 70 tRNA genes, 8 ncRNA genes, 2 CRISPRs and 126 pseudogenes. We believe that the information of this first, high-quality, complete, closed genome of P. atrosepticum strain isolated from host plant grown in subarctic agricultural region will provide resources for comparative genomic studies and for analyses targeting climatic adaptation and ecological fitness mechanisms present in P. atrosepticum.


title: Bacterial predation on T4 phages

abstract:
BackgroundBacterial consumption of viruses has never yet been reported, even though bacteria feed on almost anything. Viruses are omnipresent predators for all organisms, but have no acknowledged active biocontrol. The viral biomass undoubtedly reintegrates the trophic cycles, however the mechanisms of this phase still remain unknown.

MethodsHere, we used stable isotope probing with 13C labelled T4 phages to monitor the increase of density of the bacterial DNA concomitant with the decrease of plaque forming units. We used 12C T4 phages as control.

ResultsT4 phage disappearance in wastewater sludge was found to occur mainly through predation by Aeromonadacea. Phage consumption also favours significant in situ bacterial growth. Furthermore, an isolated strain of Aeromonas was observed to grow on T4 phages as sole source of carbon, nitrogen and phosphorus.

Conclusionsbacterial species are capable of consuming bacteriophages in situ, which is likely a widespread and underestimated type of biocontrol.This assay is anticipated as a starting point for harnessing the bacterial potential in limiting the diffusion of harmful viruses within environments such as gut or water.


title: Proteome of actin stress fibers

abstract: Stress fibers (SFs), which are actomyosin structures, reorganize in response to various cues to maintain cellular homeostasis. Currently, the protein components of SFs are only partially identified, limiting our understanding of their responses. Here we isolate SFs from huma fibroblasts HFF-1 to determine with proteomic analysis the whole protein components and how they change with replicative senescence (RS), a state where cells decline in ability to replicate after repeated divisions. We found that at least 263 proteins are associated with SFs, and 101 of them are upregulated with RS, by which SFs become larger in size. Among them, we focused on eEF2 (eukaryotic translation elongation factor 2) as it exhibited upon RS the most significant increase in abundance. We show that eEF2 is critical to the reorganization and stabilization of SFs in senescent fibroblasts. Our findings provide a novel molecular basis for SFs to be reinforced to resist cellular senescence.

category: cell biology


title: Anatomical Structures, Cell Types, and Biomarkers Tables Plus 3D Reference Organs in Support of a Human Reference Atlas

abstract: 1.This paper reviews efforts across 16 international consortia to construct human anatomical structures, cell types, and biomarkers (ASCT+B) tables and three-dimensional reference organs in support of a Human Reference Atlas. We detail the ontological descriptions and spatial three-dimensional anatomical representations together with user interfaces that support the registration and exploration of human tissue data. Four use cases are presented to demonstrate the utility of ASCT+B tables for advancing biomedical research and improving health.


title: Distinct spatiotemporal contribution of morphogenetic events and mechanical tissue coupling during Xenopus neural tube closure

abstract: Neural tube closure (NTC) is a fundamental process during vertebrate embryonic development and is indispensable for the formation of the central nervous system. Here, using Xenopus laevis embryos, live imaging, single cell tracking, optogenetics and loss of function experiments we examine the contribution of convergent extension (CE) and apical constriction (AC) and we define the role of the surface ectoderm (SE) during NTC. We show that NTC is a two-stage process and that CE and AC do not overlap temporally while their spatial activity is distinct. PCP driven CE is restricted to the caudal part of the neural plate (NP) and takes place during the first stage. CE is essential for correct positioning of the NP rostral most region in the midline of the dorsoventral axis. AC occurs after CE throughout the NP and is the sole contributor of anterior NTC. We go on to show that the SE is mechanically coupled with the NP providing resistive forces during NTC. Its movement towards the midline is passive and driven by forces generated through NP morphogenesis. Last, we show that increase of SE resistive forces is detrimental for NP morphogenesis, showing that correct SE development is permissive for NTC.

category: developmental biology


title: Genetic and pharmacological causes of germline hypermutation

abstract: Mutation in the germline is the source of all evolutionary genetic variation and a cause of genetic disease. Previous studies have shown parental age to be the primary determinant of the number of new germline mutations seen in an individuals genome. Here we analysed the genome-wide sequences of 21,879 families with rare genetic diseases and identified 12 hypermutated individuals with between two and seven times more de novo single nucleotide variants (dnSNVs) than expected. In most of these families (8/12) the excess mutations could be attributed to the father. We determined that two of these families had genetic drivers of germline hypermutation, with the fathers carrying damaging genetic variation in known DNA repair genes, causing distinctive mutational signatures. For five families, by analysing clinical records and mutational signatures, we determined that paternal exposure to chemotherapeutic agents prior to conception was a key driver of hypermutation. Our results suggest that the germline is well protected from mutagenic effects, hypermutation is rare and relatively modest in degree and that most hypermutated individuals will not have a genetic disease.

category: genomics


title: Genetic and chemotherapeutic causes of germline hypermutation


title: The draft chromosome-level genome assembly of tetraploid ground cherry (Prunus fruticosa Pall.) from long reads

abstract:
BackgroundCherries are stone fruits and belong to the economically important plant family of Rosaceae with worldwide cultivation of different species. The ground cherry, Prunus fruticosa Pall. is one ancestor of cultivated sour cherry, an important tetraploid cherry species. Here, we present a long read chromosome-level draft genome assembly and related plastid sequences using the Oxford Nanopore Technology PromethION platform and R10.3 pore type.

FindingThe final assemblies obtained from 117.3 Gb cleaned reads representing 97x coverage of expected 1.2 Gb tetraploid (2n=4x=32) and 0.3 Gb haploid (1n=8) genome sequence of P. fruticosa were calculated. The N50 contig length ranged between 0.3 and 0.5 Mb with the longest contig being [~]6 Mb. BUSCO estimated a completeness between 98.7 % for the 4n and 96.1 % for the 1n datasets.

Using a homology and reference based scaffolding method, we generated a final consensus genome sequence of 366 Mb comprising eight chromosomes. The N50 scaffold was [~]44 Mb with the longest chromosome being 66.5 Mb.

The repeat content was estimated to [~]190 Mb (52 %) and 58,880 protein-coding genes were annotated. The chloroplast and mitochondrial genomes were 158,217 bp and 383,281 bp long, which is in accordance with previously published plastid sequences.

ConclusionThis is the first report of the genome of ground cherry (P. fruticosa) sequenced by long read technology only. The datasets obtained from this study provide a foundation for future breeding, molecular and evolutionary analysis in Prunus studies.


title: Muon: multimodal omics analysis framework

abstract:
Advances in multi-omics technologies have led to an explosion of multimodal datasets to address questions ranging from basic biology to translation. While these rich data provide major opportunities for discovery, they also come with data management and analysis challenges, thus motivating the development of tailored computational solutions to deal with multi-omics data.

Here, we present a data standard and an analysis framework for multi-omics -- MUON -- designed to organise, analyse, visualise, and exchange multimodal data. MUON stores multimodal data in an efficient yet flexible data structure, supporting an arbitrary number of omics layers. The MUON data structure is interoperable with existing community standards for single omics, and it provides easy access to both data from individual omics as well as multimodal dataviews. Building on this data infrastructure, MUON enables a versatile range of analyses, from data preprocessing, the construction of multi-omics containers to flexible multi-omics alignment.


title: AltumAge: A Pan-Tissue DNA-Methylation Epigenetic Clock Based on Deep Learning

abstract: Several age predictors based on DNA methylation, dubbed epigenetic clocks, have been created in recent years, with the vast majority based on regularized linear regression. This study explores the improvement in the performance and interpretation of epigenetic clocks using deep learning. First, we gathered 143 publicly available data sets from several human tissues to develop AltumAge, a neural network framework that is a highly accurate and precise age predictor. Compared to ElasticNet, AltumAge performs better for within-data set and cross-data set age prediction, being particularly more generalizable in older ages and new tissue types. We then used deep learning interpretation methods to learn which methylation sites contributed to the final model predictions. We observe that while most important CpG sites are linearly related to age, some highly-interacting CpG sites can influence the relevance of such relationships. Using chromatin annotations, we show that the CpG sites with the highest contribution to the model predictions were related to gene regulatory regions in the genome, including proximity to CTCF binding sites. We also found age-related KEGG pathways for genes containing these CpG sites. Lastly, we perform downstream analyses of AltumAge to explore its applicability and compare its age acceleration with Horvaths model. We show that our neural network approach predicts higher age acceleration for tumors and for cells that exhibit age-related changes in vitro, such as replicative senescence and mitochondrial dysfunction. Altogether, our neural network approach provides significant improvement and flexibility to current epigenetic clocks for both performance and model interpretability.


title: Improving epigenetic clock performance and interpretation with deep learning


title: Intermediate structural hierarchy in biological networks modulates the fractal dimension and force distribution of percolating clusters

abstract: Globular protein hydrogels are an emerging class of materials with the potential for rational design, and a generalised understanding of how their network properties emerge from the structure and dynamics of the building block is a key challenge. Here we computationally investigate the effect of intermediate (polymeric) nanoscale structure on the formation of protein hydrogels. We show that changes in both the cross-link topology and flexibility of the polymeric building block lead to changes in the force transmission around the system, and provide insight into the dynamic network formation processes.

category: biophysics


title: The impact of the spatial heterogeneity of resistant cells and fibroblasts on treatment response

abstract: A long-standing practice in the treatment of cancer is that of hitting hard with the maximum tolerated dose to eradicate tumors. This continuous therapy, however, selects for resistant cells, leading to the failure of the treatment. A different type of treatment strategy, adaptive therapy, has recently been shown to have a degree of success in both preclinical xenograft experiments and clinical trials. Adaptive therapy is used to maintain a tumors volume by exploiting the competition between drug-sensitive and drug-resistant cells with minimum effective drug doses or timed drug holidays. To further understand the role of competition in the outcomes of adaptive therapy, we developed a 2D on-lattice agent-based model. Our simulations show that the superiority of the adaptive strategy over continuous therapy depends on the local competition shaped by the spatial distribution of resistant cells. Cancer cell migration and increased carrying capacity accelerate the progression of the tumor under both types of treatments by reducing the spatial competition. Intratumor competition can also be affected by fibroblasts, which produce microenvironmental factors that promote cancer cell growth. Our simulations show that the spatial architecture of fibroblasts modulates the benefits of adaptive therapy. Finally, as a proof of concept, we simulated the outcomes of adaptive therapy in multiple metastatic sites composed of different spatial distributions of fibroblasts and drug-resistant cell populations.


title: Atomic force microscopy reveals the mechanical properties of breast cancer bone metastases

abstract: Mechanically dependent processes are essential in cancer metastases. However, reliable mechanical characterisation of metastatic cancer remains challenging whilst maintaining the tissue complexity and an intact sample. Using atomic force microscopy, we quantified the micro-mechanical properties of relatively intact metastatic breast tumours and their surrounding bone microenvironment isolated from mice, and compared with other breast cancer models both ex vivo and in vitro. A unique mechanical distribution of extremely low elastic modulus and viscosity was identified on metastatic tumours, which were significantly more compliant than both 2D in vitro cultured cancer cells and subcutaneous tumour explants. The presence of mechanically distinct metastatic tumour did not result in alterations of the mechanical properties of the surrounding microenvironment at meso-scale distances (> 200 {micro}m). These findings demonstrate the utility of atomic force microscopy in studies of complex tissues and provide new insights into the mechanical properties of cancer metastases in bone.


title: Testing covariance models for MEG source reconstruction of hippocampal activity

abstract: Beamforming is one of the most commonly used source reconstruction methods for magneto- and electroencephalography (M/EEG). One underlying assumption, however, is that distant sources are uncorrelated and here we tested whether this is an appropriate model for the human hippocampal data. We revised the Empirical Bayesian Beamfomer (EBB) to accommodate specific a-priori correlated source models. We showed in simulation that we could use model evidence (as approximated by Free Energy) to distinguish between different correlated and uncorrelated source scenarios. Using group MEG data in which the participants performed a hippocampal-dependent task, we explored the possibility that the hippocampus or the cortex or both were correlated in their activity across hemispheres. We found that incorporating a correlated hippocampal source model significantly improved model evidence. Our findings help to explain why, up until now, the majority of MEG-reported hippocampal activity (typically making use of beamformers) has been estimated as unilateral.


title: Liberation from fibrogenesis or tumorigenesis via cellular senescence by a noble small molecule

abstract:
BackgroundUncontrolled proliferative diseases such as fibrosis or cancer can be fatal. We previously found that a compound containing a chromone scaffold, ONG41008, had potent anti-fibrotic effects in diseased human lung myofibroblasts but not normal human lung fibroblasts.

MethodsWe investigated the effects of ONG41008 on tumor cells, and compared these effects with those in pathogenic myofibrotic cells and normal fibroblasts cells.

FindingsStimulation of A549 lung carcinoma epithelial cells with ONG41008 resulted in cellular senescence, indicating that dysregulated cell proliferation is common to fibrotic cells and tumor cells. Replicative senescence of A549 cells resulted in multinucleation, which was followed by oncogene-induced senescence. There was significant upregulation of expression and nuclear translocation of p-TP53 and p16 in ONG41008-treated A549 cells, and all cells died after 72 hr. Similar effects occurred after ONG41008 treatment in several human aggressive cancer cell lines such as PANC1, MCF7, PC3, or primary non-small cell lung carcinoma cells. Unlike cisplatin, ONG41008 was not toxic to normal human lung fibroblasts or primary prostate epithelial cells, suggesting ONG41008 can distinguish the intracellular microenvironment between normal cells and aged or diseased cells. This effect might occur as a result of the increased NAD/NADH ratio or increased lactate dehydrogenase levels in aged or diseased cells.

InterpretationTo our best knowledge, this is the first study to show that a small molecule can arrest uncontrolled proliferation during fibrogenesis or tumorigenesis in vitro. ONG41008 could be a potential drug for a broad range of fibrotic or tumorigenic diseases.

Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSThe notion that aging is a disease and that diseases occur as a consequence of aging was first put forward by David Sinclair and colleagues (Aging Cell;14(4):497-510). There are biological systems that provide evidence for this notion; for example, somatic cells can revert to embryonic cells, producing younger somatic cells. This phenomenon underlies induced pluripotent stem cells. Another example is that some types of jellyfish can live forever. These examples suggest that a counter-aging program exists in animals. Human diseases are the manifestations of cell aging generated by the accumulation of somatic mutations. Aged and pathogenic cells are senescent, so a drug that specifically targeted senescent cells might initiate a cellular program that could ameliorate age-associated disease. Indeed, the kinase inhibitor dasatinib induces cellular senescence (Clin Ther 2007 29:2289-2308). In 2017, two drugs that target senescent cells were identified: quercetin and fisetin. These drugs selectively kill senescent cells, and are referred to as senolytic drugs or senotherapeutics (Aging 2017 8;9(3):955-963). Although it is established that senescent cells accumulate in cancer and idiopathic pulmonary fibrosis (Nat Commun 2017 23;8 :14532), the effect of senolytic drugs in these diseases is largely unknown.

Added value of this studyThis study characterized a novel drug, termed ONG41008, which was found to have both senogenic and senolytic effects in cell-based assays. ONG41008 induced senescence in myofibroblasts and several cancer cell lines representative of aggressive human cancers, which was followed by cell death. Importantly, ONG41008 exhibited essentially no toxicity on normal human lung fibroblasts or primary prostate epithelial cells.

Implication of all the evidenceBased on our results, we believe that ONG41008 is a potent inducer of cellular senescence (replicative senescence and oncogene-induced senescence) and causes arrest of uncontrolled, pathogenic proliferation of myofibroblasts or cancer cells.


title: Liberation from fibrogenesis or tumorigenesis via cellular senescence by a novel small molecule


title: A small molecule that promotes cellular senescence prevents fibrogenesis and tumorigenesis in vitro


title: CDK12 is Necessary to Promote Epidermal Differentiation through Transcription Elongation

abstract: Proper differentiation of the epidermis is essential to prevent water loss and to protect the body from the outside environment. Perturbations in this process can lead to a variety of skin diseases that impacts 1 in 5 people. While transcription factors that control epidermal differentiation have been well characterized, other aspects of transcription control such as elongation are poorly understood. Here we show that of the two cyclin dependent kinases (CDK12 and CDK13), that are known to regulate transcription elongation, only CDK12 is necessary for epidermal differentiation. Depletion of CDK12 led to loss of differentiation gene expression and absence of skin barrier formation in regenerated human epidermis. CDK12 binds to genes that code for differentiation promoting transcription factors (GRHL3, KLF4, and OVOL1) and is necessary for their elongation. CDK12 is necessary for elongation by promoting Ser2 phosphorylation on the C-terminal domain of RNA polymerase II and the binding of the elongation factor SPT6 to target genes. Our results suggest that control of transcription elongation by CDK12 plays a prominent role in adult cell fate decisions.


title: Building Back More Equitable STEM Education: Teach Science by Engaging Students in Doing Science

abstract: The COVID-19 pandemic is a national tragedy, one that has focused our attention on both the need to improve science education and the need to confront systemic racism in our country. We know that active learning strategies, in particular research experiences, can engage and empower STEM undergraduates, effectively closing the achievement gap for historically excluded persons. The apprenticeship model for STEM training - supervised research under a dedicated mentor - is highly effective, but out of reach for most students. Recent efforts have demonstrated that Course-based Undergraduate Research Experiences (CUREs) can be an effective approach for making STEM research accessible for all. Our meta-analysis of CUREs finds that published examples now cover the breadth of the typical undergraduate biology curriculum. A thoughtfully designed CURE can go beyond foundational knowledge and analytical thinking to include career-related skills, e.g., teamwork and communication. Similarly, it can be designed with equity as a foundational principle, taking into account the unique contributions of all students and their varying needs. We provide here an example framework (The "Do Science Framework") for making STEM training more effective and inclusive using CUREs. While CUREs do not inherently address equity, there can be no equity in STEM education without equal access to research participation, and progress toward this goal can be achieved using CUREs. However, implementing new CUREs is not a trivial undertaking, particularly at schools with high teaching loads and little or no research infrastructure, including many community colleges. We therefore propose a National Center for Science Engagement to support this transition, building on experiences of current nationally established CUREs as well as the work of many individual faculty. In the aftermath of the COVID-19 pandemic, academia has a renewed responsibility to dismantle structural inequities in education; engaging all STEM students in research can be a key step.

category: scientific communication and education


title: Subcellular proteomics of dopamine neurons in the mouse brain reveals axonal enrichment of proteins encoded by Parkinson's disease-linked genes

abstract: Dopaminergic neurons modulate neural circuits and behaviors via dopamine release from expansive, long range axonal projections. The elaborate cytoarchitecture of these neurons is embedded within complex brain tissue, making it difficult to access the neuronal proteome using conventional methods. Here, we demonstrate APEX2 proximity labeling within genetically targeted neurons in the mouse brain, enabling subcellular proteomics with cell type-specificity. By combining APEX2 biotinylation with mass spectrometry, we mapped the somatodendritic and axonal proteomes of midbrain dopaminergic neurons. Our dataset reveals the proteomic architecture underlying proteostasis, axonal metabolism, and neurotransmission in these neurons. We find a significant enrichment of proteins encoded by Parkinsons disease-linked genes in striatal dopaminergic axons, including proteins with previously undescribed axonal localization. These proteomic datasets provide a resource for neuronal cell biology, and this approach can be readily adapted for study of other neural cell types.


title: Analysis of 56K genomes identifies the relationship between antibiotic and metal resistance co-Occurrence and the spread of multidrug-resistant non-typhoidal Salmonella

abstract: Salmonella enterica is common foodborne pathogen that generates both enteric and systemic infections in hosts. Antibiotic resistance is common is certain serovars of the pathogen and of great concern to public health. Recent reports have documented the co-occurrence of metal resistance with antibiotic resistance in one serovar of S. enterica. Therefore, we sought to identify possible co-occurrence in a large genomic dataset. Genome assemblies of 56,348 strains of S. enterica comprising 20 major serovars were downloaded from NCBI. The downloaded assemblies were quality controlled and in silico serotyped to ensure consistency and avoid improper annotation from public databases. Metal and antibiotic resistance genes were identified in the genomes as well as plasmid replicons. Co-current genes were identified by constructing a co-occurrence matrix and group the genes using k-means clustering. Three groups of co-occurrent genes were identified using k-means clustering. Group 1 was comprised of the pco and sil operons that confer resistance to copper and silver respectively. Group 1 was distributed across four serovars. Group 2 contained the majority of the genes and little to no co-occurrence was observed. Metal and antibiotic co-occurrence was identified in group 3 that contained genes conferring resistance to: arsenic, mercury, beta-lactams, sulfonamides, and tetracyclines. Group 3 genes were also associated with an IncQ1 class plasmid replicon. Metal and antibiotic cooccurrence was isolated to one clade of S. enterica I 4,[5],12:i:.


title: Inducible and reversible inhibition of miRNA-mediated gene repression in vivo

abstract: Although virtually all gene networks are predicted to be controlled by miRNAs, the contribution of this important layer of gene regulation to tissue homeostasis in adult animals remains unclear. Gain and loss of function experiments have provided key insights into the specific function of individual miRNAs, but effective genetic tools to study the functional consequences of global inhibition of miRNA activity in vivo are lacking. Here we report the generation and characterization of a genetically engineered mouse strain in which miRNA-mediated gene repression can be reversibly inhibited without affecting miRNA biogenesis or abundance. We demonstrate the usefulness of this strategy by investigating the consequences of acute inhibition of miRNA function in adult animals. We find that different tissues and organs respond differently to global loss of miRNA function. While miRNA-mediated gene repression is essential for the homeostasis of the heart and the skeletal muscle, it is largely dispensable in the majority of other organs. Even in tissues where it is not required for homeostasis, such as the intestine and hematopoietic system, miRNA activity can become essential during regeneration following acute injury. These data support a model where many metazoan tissues primarily rely on miRNA function to respond to potentially pathogenic events.

category: molecular biology


title: Multilocus adaptation to vaccination

abstract: Pathogen adaptation to public health interventions, such as vaccination, may take tortuous routes and involve multiple mutations at distinct locations in the pathogen genome, acting on distinct phenotypic traits. Despite its importance for public health, how these multilocus adaptations jointly evolve is poorly understood. Here we consider the joint evolution of two adaptations: the pathogens ability to escape the vaccine-induced immune response and adjustments to the pathogens virulence and transmissi-bility. We elucidate the role played by epistasis and recombination, with an emphasis on the different protective effects of vaccination. We show that vaccines reducing transmission and/or increasing clearance generate positive epistasis between the vaccine-escape and virulence alleles, favouring strains that carry both mutations, whereas vaccines reducing virulence mortality generate negative epistasis, favouring strains that carry either mutation, but not both. High rates of recombination can affect these predictions. If epistasis is positive, frequent recombination can lead to the sequential fixation of the two mutations and prevent the transient build-up of more virulent escape strains. If epistasis is negative, frequent recombination between loci can create an evolutionary bistability, such that whichever adaptation is more accessible tends to be favoured in the long-term. Our work provides a timely alternative to the variant-centered perspective on pathogen adaptation and captures the effect of different types of vaccines on the interference between multiple adaptive mutations.


title: Screening thousands of transcribed coding and non-coding regions reveals sequence determinants of RNA polymerase II elongation potential

abstract: Organismal growth and development rely on RNA Polymerase II (RNAPII) synthesizing the appropriate repertoire of messenger RNAs (mRNAs) from protein-coding genes. Productive elongation of full-length transcripts is essential for mRNA function, however what determines whether an engaged RNAPII molecule will terminate prematurely or transcribe processively remains poorly understood. Notably, despite a common process for transcription initiation across RNAPII-synthesized RNAs1, RNAPII is highly susceptible to termination when transcribing non-coding RNAs such as upstream antisense RNAs (uaRNAs) and enhancers RNAs (eRNAs)2, suggesting that differences arise during RNAPII elongation. To investigate the impact of transcribed sequence on elongation potential, we developed a method to screen the effects of thousands of INtegrated Sequences on Expression of RNA and Translation using high-throughput sequencing (INSERT-seq). We found that higher AT content in uaRNAs and eRNAs, rather than specific sequence motifs, underlies the propensity for RNAPII termination on these transcripts. Further, we demonstrate that 5 splice sites exert both splicing-dependent and autonomous, splicing-independent stimulation of transcription, even in the absence of polyadenylation signals. Together, our results reveal a potent role for transcribed sequence in dictating gene output at mRNA and non-coding RNA loci, and demonstrate the power of INSERT-seq towards illuminating these contributions.


title: Glucocorticoid receptor collaborates with pioneer factors and AP-1 to execute genome-wide regulation

abstract: AO_SCPLOWBSTRACTC_SCPLOWThe glucocorticoid receptor (GR) regulates transcription through binding to specific DNA motifs, particularly at enhancers. While the motif to which it binds is constant across cell types, GR has cell type-specific binding at genomic loci, resulting in regulation of different genes. The presence of other bound transcription factors (TFs) is hypothesized to strongly influence where GR binds. Here, we addressed the roles of other TFs in the glucocorticoid response by comparing changes in GR binding and nascent transcription at promoters and distal candidate cis-regulatory elements (CCREs) in two distinct human cancer cell types. We found that after glucocorticoid treatment, GR binds to thousands of genomic loci that are primarily outside of promoter regions and are potentially enhancers. The majority of these GR binding sites are cell-type specific, and they are associated with pioneer factor binding. A small fraction of GR occupied regions (GORs) displayed increased bidirectional nascent transcription, which is a characteristic of many active enhancers, after glucocorticoid treatment. Non-promoter GORs with increased transcription were specifically enriched for AP-1 binding prior to glucocorticoid treatment. These results support a model of transcriptional regulation in which multiple classes of TFs are required. The pioneer factors increase chromatin accessibility, facilitating the binding of GR and additional factors. AP-1 binding poises a fraction of accessible sites to be rapidly transcribed upon glucocorticoid-induced GR binding. The coordinated activity of multiple TFs then results in cell type-specific changes in gene expression. We anticipate that many models of inducible gene expression also require multiple distinct TFs that act at multiple steps of transcriptional regulation.


title: Two marine GH29 α-L-fucosidases from an uncultured Paraglaciecola sp. specifically hydrolyze fucosyl-N-acetylglucosamine regioisomers

abstract: O_SCPLOWLC_SCPLOW-Fucose is the most widely distributed O_SCPLOWLC_SCPLOW-hexose in marine and terrestrial environments, and presents a variety of functional roles. O_SCPLOWLC_SCPLOW-Fucose is the major monosaccharide in the polysaccharide fucoidan from cell walls of brown algae, and is found in human milk oligosaccharides and the Lewis blood group system, where it is important in cell signaling and immune response stimulation. Removal of fucose from these biomolecules is catalyzed by fucosidases belonging to different carbohydrate-active enzyme (CAZy) families. Fucosidases of glycoside hydrolase family 29 (GH29) release -O_SCPLOWLC_SCPLOW-fucose from non-reducing ends of glycans and display activities targeting different substrate compositions and linkage types. While several GH29 fucosidases from terrestrial environments have been characterized, much less is known about marine members of GH29 and their substrate specificities, as only four marine GH29 enzymes were previously characterized. Here, five GH29 fucosidases originating from an uncultured fucoidan-degrading marine bacterium (Paraglaciecola sp.) were cloned and produced recombinantly in E. coli. All five enzymes (Fp231, Fp239, Fp240, Fp251, Fp284) hydrolyzed the synthetic substrate CNP--O_SCPLOWLC_SCPLOW-fucose. By screening each of these enzymes against up to 17 fucose-containing oligosaccharides Fp231 and Fp284 showed strict substrate specificities against the fucosyl-N-acetylglucosamine regioisomers Fuc(1,4)GlcNAc and Fuc(1,6)GlcNAc, respectively, the former representing a new specificity. Fp231 is a monomeric enzyme with pH and temperature optima at pH 5.6-6.0 and 25{degrees}C, hydrolyzing Fuc(1,4)GlcNAc with kcat = 1.3 s-1 and Km = 660 M. Altogether, the findings extend our knowledge about GH29 family members from the marine environment, which are so far largely unexplored.

category: biochemistry


title: Shade-induced WRKY transcription factors restrict root growth during the shade avoidance response

abstract:
Shade-intolerant plants rapidly elongate their stems, branches, and leaf stalks to compete with their neighboring vegetation to maximize sunlight capture for photosynthesis. This rapid growth adaptation, known as the shade avoidance response (SAR), comes at a cost; reduced biomass, crop yield, and root growth. Significant progress has been made on the mechanistic understanding of hypocotyl elongation during SAR; however, the molecular account of how root growth is repressed is not well understood. Here, we explore the mechanisms by which low red:far-red induced SAR restrict the primary and lateral root (LR) growth. By analyzing whole-genome transcriptome, we identified a core set of shade-induced genes in the roots of Arabidopsis and tomato seedlings grown in the shade. Abiotic and biotic stressors also induce many of these shade-induced genes and are predominantly regulated by the WRKY transcription factors. Correspondingly, a majority of the WRKYs were also among the shade-induced genes. Functional analysis using transgenics of these shade-induced WRKYs revealed their role is essentially to restrict primary root and LR growth in the shade, and captivatingly, they did not affect hypocotyl elongation. Similarly, we also show that ethylene hormone signaling is necessary to limit root growth in the shade. Our study proposes that during SAR, shade-induced WRKY26, 45, and 75, and ethylene reprogram gene expression in the root to restrict its growth and development. The reduced growth of root organs helps the plant divert its critical resources to the elongating organs in the shoot to ensure competitiveness under limiting photosynthetic radiation.

One sentence summaryShade represses root growth by inducing WRKY transcription factors.


title: Interference at Influenza Hemagglutinin Antigenic-Sites Determines Antibody Levels and Specificities after Repeat Vaccination

abstract:
BackgroundIt is recommended that children receive a dose of the influenza vaccine at 6 months of age and a second dose the following season. In some years, the second dose will be the same vaccine formulation, in others years it with be re-formulated to include HA proteins derived from antigenically drifted or shifted circulating influenza strains. In addition, natural exposure to influenza can create permanent changes to the memory B cell repertoire and specificities. The effect that the specificity of pre-existing humoral immunity has on antibody levels and specificity after repeat vaccination is an ongoing research area.

MethodsWe used a computational framework (ssMod.v1) to simulate scenarios that occurred during the 2009 influenza pandemic: children receiving a second dose who have previously exposed to the 2009 influenza HA antigen, children previously exposed to an HA antigen antigenically similar to the 2009 influenza HA antigen, and children previously exposed to an antigenically dissimilar strain. To assess the contribution of pre-existing immunity, two experimental permutations in the sMod.v1 were made: elimination of antibody-mediated antibody clearance of vaccine (HA) antigen by pre-existing antibodies and elimination of the ability of memory B cells to form germinal centers. In the simulation, 30 days after repeat vaccination antibody specificities were examined against 12 antigenically historical vaccine/HA variant influenza strains for each of the five canonical antigenic-sites and the subdominant, conserved, stalk antigenic-site.

ResultsWe found that elimination of antibody-mediated antigen clearance significantly increased antibody levels while elimination of the ability of memory B cells to form germinal center reactions significantly decreased the total antibody levels, but this was dependent on the antigenic relationship between the original vaccine and repeat vaccine and the particular antigenic-site. Moreover, highly-cross-reactive antibody was highest when the antigenic distance between original vaccine HA antigen and repeat vaccine HA antigen was larger and antibody-mediated antigen clearance was eliminated.

category: immunology


title: Structural basis for SARS-CoV-2 Nucleocapsid protein recognition by single-domain antibodies

abstract: The COVID-19 pandemic, caused by the coronavirus SARS-CoV-2, is the most severe public health event of the twenty-first century. While effective vaccines against SARS-CoV-2 have been developed, there remains an urgent need for diagnostics to quickly and accurately detect infections. Antigen tests, particularly those that detect the abundant SARS-CoV-2 Nucleocapsid protein, are a proven method for detecting active SARS-CoV-2 infections. Here we report high-resolution crystal structures of three llama-derived single-domain antibodies that bind the SARS-CoV-2 Nucleocapsid protein with high affinity. Each antibody recognizes a specific folded domain of the protein, with two antibodies recognizing the N-terminal RNA binding domain and one recognizing the C-terminal dimerization domain. The two antibodies that recognize the RNA binding domain affect both RNA binding affinity and RNA-mediated phase separation of the Nucleocapsid protein. All three antibodies recognize highly-conserved surfaces on the Nucleocapsid protein, suggesting that they could be used to develop affordable diagnostic tests to detect all circulating SARS-CoV-2 variants.


title: Synergistic inhibition of two host factors that facilitate entry of Severe Acute Respiratory Syndrome Coronavirus 2

abstract:
Repurposing FDA-approved inhibitors able to prevent infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could provide a rapid path to establish new therapeutic options to mitigate the effects of coronavirus disease 2019 (COVID-19). Proteolytic cleavages of the spike S protein of SARS-CoV-2, mediated by the host cell proteases cathepsin and TMPRSS2, alone or in combination, are key early activation steps required for efficient infection. The PIKfyve kinase inhibitor apilimod interferes with late endosomal viral traffic, and through an ill-defined mechanism prevents in vitro infection through late endosomes mediated by cathepsin. Similarly, inhibition of TMPRSS2 protease activity by camostat mesylate or nafamostat mesylate prevents infection mediated by the TMPRSS2-dependent and cathepsin-independent pathway. Here, we combined the use of apilimod with camostat mesylate or nafamostat mesylate and found an unexpected ~5-10-fold increase in their effectiveness to prevent SARS-CoV-2 infection in different cell types. Comparable synergism was observed using both, a chimeric vesicular stomatitis virus (VSV) containing S of SARS-CoV-2 (VSV-SARS-CoV-2) and SARS-CoV-2 virus. The substantial ~5-fold or more decrease of half maximal effective concentrations (EC50 values) suggests a plausible treatment strategy based on the combined use of these inhibitors.

IMPORTANCEInfection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing the coronavirus disease 2019 (COVID-2019) global pandemic. There are ongoing efforts to uncover effective antiviral agents that could mitigate the severity of the disease by controlling the ensuing viral replication. Promising candidates include small molecules that inhibit the enzymatic activities of host proteins, thus preventing SARS-CoV-2 entry and infection. They include Apilimod, an inhibitor of PIKfyve kinase and camostat mesylate and nafamostat mesylate, inhibitors of TMPRSS2 protease. Our research is significant for having uncovered an unexpected synergism in the effective inhibitory activity of apilimod used together with camostat mesylate or with nafamostat mesylate.


title: Synergistic block of SARS-CoV-2 infection by combined drug inhibition of the host entry factors PIKfyve kinase and TMPRSS2 protease


title: Virucidal activity of a proprietary blend of plant-based oils (Viruxal) against SARS-CoV-2 and influenza viruses - an in vitro study

abstract:
BackgroundThe emergence of a novel coronavirus known as SARS-CoV-2 resulting in a global pandemic COVID-19 has led to a dramatic loss of life worldwide and presented an unprecedented challenge to public health. Viruxal is a medical device in a form of a nasal and oral spay containing a a proprietary blend of plant-based oils which acts against enveloped viruses. The aim of this study was to evaluate the virus deactivation activity of Viruxal against SARS-CoV-2 and Influenza A(H1N1) viruses.

MethodsAn assay to detect virucidal activity was performed with four concentrations of Viruxal on two virus suspensions. Assessments were made based on log reduction values measured from the assay.

ResultsViruxal exhibited virucidal activity by reducing virus titer more than 90% for the enveloped viruses SARS-CoV-2 and influenza A(H1N1) after 30 minutes contact.

ConclusionsViruxal was validated for its potential usefulness as a medical device for treatment and prevention of enveloped respiratory viruses.


title: SARS-CoV-2 cell-to-cell spread occurs rapidly and is insensitive to antibody neutralization

abstract: Viruses increase the efficiency of close-range transmission between cells by manipulating cellular physiology and behavior, and SARS-CoV-2 uses cell fusion as one mechanism for cell-to-cell spread. Here we visualized infection using time-lapse microscopy of a human lung cell line and used live virus neutralization to determine the sensitivity of SARS-CoV-2 cell-to-cell spread to neutralizing antibodies. SARS-CoV-2 infection rapidly led to cell fusion, forming multinucleated cells with clustered nuclei which started to be detected at 6h post-infection. To compare sensitivity of cell-to-cell spread to neutralization, we infected either with cell-free virus or with single infected cells expressing on their surface the SARS-CoV-2 spike protein. We tested two variants of SARS-CoV-2: B.1.117 containing only the D614G substitution, and the escape variant B.1.351. We used the much smaller area of single infected cells relative to infection foci to exclude any input infected cells which did not lead to transmission. The monoclonal antibody and convalescent plasma we tested neutralized cell-free SARS-CoV-2, with the exception of B.1.351 virus, which was poorly neutralized with plasma from non-B.1.351 infections. In contrast, cell-to-cell spread of SARS-CoV-2 showed no sensitivity to monoclonal antibody or convalescent plasma neutralization. These observations suggest that, once cells are infected, SARS-CoV-2 may be more difficult to neutralize in cell types and anatomical compartments permissive for cell-to-cell spread.


title: 3-hydroxyanthranilic acid - a new metabolite for healthy lifespan extension

abstract: The metabolism of tryptophan to nicotinamide adenine dinucleotide (NAD+) through the kynurenine pathway is increasingly linked to aging and age-associated disease. Kynurenine pathway enzymes and metabolites influence a range of molecular processes critical to healthy aging, including regulation of inflammatory and immune responses, cellular redox homeostasis, and energy production. Aberrant kynurenine metabolism is observed during normal aging and has been implicated in a range of age-associated pathologies, including chronic inflammation, atherosclerosis, neurodegeneration, and cancer. In previous work, we and others identified three genes--kynu-1, tdo-2, and acsd-1--encoding kynurenine pathway enzymes for which decreasing expression extends lifespan in invertebrate models. Here we report that knockdown of haao-1, a fourth kynurenine pathway gene encoding the enzyme 3-hydroxyanthranilic acid dioxygenase (HAAO), extends lifespan by ~30% and delays age-associated decline in health in Caenorhabditis elegans. This lifespan extension is mediated by increased physiological levels of the HAAO substrate 3-hydroxyanthranilic acid (3HAA). 3HAA increases resistance to oxidative stress during aging by directly degrading hydrogen peroxide and activating the Nrf2/SKN-1 oxidative stress response. Aging mice fed a diet supplemented with 3HAA are similarly long-lived. Our results identify HAAO and 3HAA as novel therapeutic targets for age-associated disease. This works provides a foundation for more detailed examination of the molecular mechanisms underlying the benefits of 3HAA, and how these mechanisms interact with other interventions both within and beyond the kynurenine pathway. We anticipate that these findings will bolster growing interest in developing pharmacological strategies to target tryptophan metabolism to improve health aging.


title: Analysis of SARS-CoV-2 mutations reveals three types of temporal dynamics and one is correlated with international travels

abstract: Coronavirus disease 2019 (COVID-19) is a contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This disease has spread globally, causing more than 161.5 million cases and 3.3 million deaths to date. Surveillance and monitoring of new mutations in the virus genome are crucial to our understanding of the adaptation of SARS-CoV-2. Moreover, how the temporal dynamics of these mutations is influenced by control measures and non-pharmaceutical interventions (NPIs) is poorly understood. Using 1 058 020 SARS-CoV-2 from sequenced COVID-19 cases from 98 countries (totaling 714 country-month combinations), we perform a normalization by COVID-19 cases to calculate the relative frequency of SARS-CoV-2 mutations and explore their dynamics over time. We found 115 mutations estimated to be present in more than 3 % of global COVID-19 cases and determined three types of mutation dynamics: High-Frequency, Medium-Frequency, and Low-Frequency. Classification of mutations based on temporal dynamics enable us to examine viral adaptation and evaluate the effects of implemented control measures in virus evolution during the pandemic. We showed that Medium-Frequency mutations are characterized by high prevalence in specific regions and/or in constant competition with other mutations in several regions. Finally, taking N501Y mutation as representative of High-Frequency mutations, we showed that level of control measure stringency negatively correlates with the effective reproduction number of SARS-CoV-2 with High-Frequency or not-High-Frequency and both follows similar trends in different levels of stringency.


title: Dynamics of SARS-CoV-2 mutations reveals regional-specificity and similar trends of N501 and High-Frequency mutation N501Y in different levels of control measures


title: Endomembrane systems are reorganized by ORF3a and Membrane (M) of SARS-CoV-2

abstract:
The endomembrane reticulum (ER) is largely reorganized by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 ORF3a and membrane (M) protein expression affects ER-derived structures including cubic membrane and double membrane vesicles in coronavirus-infected cells; however, the molecular mechanisms underlying ER remodeling remain unclear. We introduced a "plug and playable" proximity labeling tool (TurboID-GBP) for interactome mapping of GFP-tagged SARS-CoV-2 ORF3a and M proteins. Through mass spectrometric identification of the biotinylated lysine residue (K+226 Da) on the viral proteins using Spot-TurboID workflow, 117 and 191 proteins were robustly determined as ORF3a and M interactomes, respectively, and many, including RNF5 (E3 ubiquitin ligase), overlap with the mitochondrial-associated membrane (MAM) proteome. RNF5 expression was correlated to ORF3a ubiquitination. MAM formation and secreted proteome profiles were largely affected by ORF3a expression. Thus, SARS-CoV-2 may utilize MAM as a viral assembly site, suggesting novel anti-viral treatment strategies for blocking viral replication in host cells.

HighlightsO_LISARS-CoV-2 proteins ORF3a and M alter endoplasmic reticulum proteome profile
C_LIO_LIORF3a affects mitochondrial-associated membrane formation
C_LIO_LISARS-CoV-2 may utilize mitochondrial-associated membrane as viral assembly site
C_LIO_LIORF3a and M interactome proteins may serve as targets for COVID-19 treatment
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eTOC BlurbER remodelling by SARS-CoV-2 ORF3a and M protein


title: Characterization of SARS2 Nsp15 Nuclease Activity Reveals it's Mad About U

abstract: Nsp15 is a uridine specific endoribonuclease that coronaviruses employ to cleave viral RNA and evade host immune defense systems. Previous structures of Nsp15 from across Coronaviridae revealed that Nsp15 assembles into a homo-hexamer and has a conserved active site similar to RNase A. Beyond a preference for cleaving RNA 3 of uridines, it is unknown if Nsp15 has any additional substrate preferences. Here we used cryo-EM to capture structures of Nsp15 bound to RNA in pre- and post-cleavage states. The structures along with molecular dynamics and biochemical assays revealed critical residues involved in substrate specificity, nuclease activity, and oligomerization. Moreover, we determined how the sequence of the RNA substrate dictates cleavage and found that outside of polyU tracts, Nsp15 has a strong preference for purines 3 of the cleaved uridine. This work advances our understanding of how Nsp15 recognizes and processes viral RNA and will aid in the development of new anti-viral therapeutics.


title: Distinct phosphorylation signals drive acceptor versus self-ubiquitination selection by Parkin

abstract: The RBR E3 ligase parkin is recruited to the outer mitochondrial membrane (OMM) during oxidative stress where it becomes activated and ubiquitinates numerous proteins. Parkin activation involves binding of a phosphorylated ubiquitin (pUb), followed by phosphorylation of parkin itself, both mediated by the OMM kinase, PINK1. However, targeted mitochondrial proteins have little structural or sequence similarity, with the commonality between substrates being proximity to the OMM. Here, we demonstrate that parkin efficiently ubiquitinates a mitochondrial acceptor pre-ligated to pUb and phosphorylation of parkin triggers autoubiquitination activity. Mitochondrial target proteins, Miro1 or CISD1, tethered to pUb are ubiquitinated by parkin more efficiently than if alone or Ub-tethered and ubiquitin molecules are ligated to acceptor protein lysines and not pUb. Parkin phosphorylation is not required for acceptor-pUb ubiquitination. In fact, only phospho-parkin induced self-ubiquitination and deletion of Ubl or mutation at K211N inhibited self-ubiquitination. We propose divergent parkin mechanisms whereby parkin-mediated ubiquitination of acceptor proteins is driven by binding to pre-existing pUb and subsequent parkin phosphorylation triggers autoubiquitination. This finding is critical for understanding parkins role in mitochondrial homeostasis and has implications on targets for therapeutics.


title: Mitochondrial Contact Site and Cristae Organizing System (MICOS) Machinery Supports Heme Biosynthesis by Enabling Optimal Performance of Ferrochelatase

abstract: Heme is an essential cofactor required for a plethora of cellular processes in eukaryotes. In metazoans the heme biosynthetic pathway is typically partitioned between the cytosol and mitochondria, with the first and final steps taking place in the mitochondrion. The pathway has been extensively studied, and all the biosynthetic enzymes have been structurally characterized to varying extents. Nevertheless, our understanding of the regulation of heme synthesis and factors that influence this process in metazoans remains incomplete. Herein we investigate the molecular organization as well as the catalytic and structural features of the terminal pathway enzyme, ferrochelatase (Hem15), in the yeast Saccharomyces cerevisiae. Biochemical and genetic analyses reveal dynamic association of Hem15 with Mic60, a core component of the mitochondrial contact site and cristae organizing system (MICOS). Loss of MICOS negatively impacts Hem15 activity and results in accumulation of highly reactive and potentially toxic tetrapyrrole precursors that may result in oxidative damage. Restoring intermembrane connectivity in MICOS-deficient cells mitigates these cytotoxic effects. Our data provide new insights into how heme biosynthetic machinery is organized and regulated, linking mitochondrial architecture-organizing factors to heme homeostasis.


title: Biochemical insight into novel Rab-GEF activity of the mammalian TRAPPIII complex

abstract: Transport Protein Particle complexes (TRAPP) are evolutionarily conserved regulators of membrane trafficking, with this mediated by their guanine nucleotide exchange factor (GEF) activity towards Rab GTPases. In metazoans evidence suggests that two different TRAPP complexes exist, TRAPPII and TRAPPIII. These two complexes share a common core of subunits, with complex specific subunits (TRAPPC9 and TRAPPC10 in TRAPPII and TRAPPC8, TRAPPC11, TRAPPC12, TRAPPC13 in TRAPPIII). TRAPPII and TRAPPIII have distinct specificity for GEF activity towards Rabs, with TRAPPIII acting on Rab1, and TRAPPII acting on Rab1 and Rab11. The molecular basis for how these complex specific subunits alter GEF activity towards Rab GTPases is unknown. Here we have used a combination of biochemical assays, hydrogen deuterium exchange mass spectrometry (HDX-MS) and electron microscopy to examine the regulation of TRAPPII and TRAPPIIII complexes in solution and on membranes. GEF assays revealed that the TRAPPIII has GEF activity against Rab1 and Rab43, with no detectable activity against the other 18 Rabs tested. The TRAPPIII complex had significant differences in protein dynamics at the Rab binding site compared to TRAPPII, potentially indicating an important role of accessory subunits in altering the active site of TRAPP complexes. Both the TRAPPII and TRAPPIII complexes had enhanced GEF activity on lipid membranes, with HDX-MS revealing numerous conformational changes that accompany membrane association. HDX-MS also identified a membrane binding site in TRAPPC8. Collectively, our results provide insight into the functions of TRAPP complexes and how they can achieve Rab specificity.


title: Structure of the phosphoinositide 3-kinase p110γ-p101 complex reveals molecular mechanism of GPCR activation

abstract: The class IB phosphoinositide 3-kinase (PI3K), PI3K{gamma}, is a master regulator of immune cell function, and a promising drug target for both cancer and inflammatory diseases. Critical to PI3K{gamma} function is the association of the p110{gamma} catalytic subunit to either a p101 or p84 regulatory subunit, which mediates activation by G-protein coupled receptors (GPCRs). Here, we report the cryo-EM structure of a heterodimeric PI3K{gamma} complex, p110{gamma}-p101. This structure reveals a unique assembly of catalytic and regulatory subunits that is distinct from other class I PI3K complexes. p101 mediates activation through its G{beta}{gamma} binding domain, recruiting the heterodimer to the membrane and allowing for engagement of a secondary G{beta}{gamma} binding site in p110{gamma}. Multiple oncogenic mutations mapped to these novel interfaces and enhanced G{beta}{gamma} activation. A nanobody that specifically binds to the p101-G{beta}{gamma} interface blocks activation providing a novel tool to study and target p110{gamma}-p101-specific signaling events in vivo.


title: Probing Interactions of Therapeutic Antibodies with Serum via Second Virial Coefficient Measurements

abstract:
Antibody-based therapeutics are the fastest growing drug class on the market, used to treat aggressive forms of cancer, chronic autoimmune conditions, and numerous other disease states. While the specificity, affinity, and versatility of therapeutic antibodies can provide an advantage over traditional small molecule drugs, their development and optimization can be much more challenging and time-consuming. This is, in part, because the ideal formulation buffer systems used for in vitro characterization inadequately reflect the crowded biological environments (serum, endosomal lumen, etc.) that these drugs experience once administered to a patient. Such environments can perturb the binding of antibodies to their antigens and receptors, as well as homo- and hetero-aggregation, in ways that are incompletely understood, thereby altering therapeutic effect and disposition. While excluded volume effects are classically thought to favor binding, weak interactions with co-solutes in crowded conditions can inhibit binding. The second virial coefficient (B2) parameter quantifies such weak interactions and can be determined by a variety of techniques in dilute solution, but analogous methods in complex biological fluids are not well established. Here, we demonstrate that fluorescence correlation spectroscopy (FCS) is able to measure diffusive B2 values directly in undiluted serum. Apparent second virial coefficient (B2,app) measurements of antibodies in serum reveal that changes in the balance between attractive and repulsive interactions can dramatically impact global nonideality. Furthermore, our findings suggest that the common approach of isolating specific components and completing independent cross-term virial coefficient measurements is an incomplete representation of nonideality in serum. The approach presented here could enrich our understanding of the effects of biological environments on proteins in general, and advance the development of therapeutic antibodies and other protein-based therapeutics.

STATEMENT OF SIGNIFICANCEWe present FCS as an orthogonal method to traditional methods for characterizing weak, nonspecific homo- and hetero-interactions through determination of self- and cross-term second virial coefficients, respectively. We also characterize weak interactions between therapeutic antibodies and serum components through determination of an apparent second virial coefficient (B2,app) directly in undiluted serum. Our results suggest that global nonideality effects are antibody-dependent, and that attractive and repulsive interactions with co-solutes are occurring simultaneously. This approach could advance our understanding of the impact of nonideality to the biophysical and pharmacological properties of therapeutic antibodies and other engineered proteins in relevant biological environments, and could accelerate the development and optimization of protein-based therapeutics.


title: Genome-wide identification and analysis of prognostic features in human cancers

abstract: Clinical decisions in cancer rely on precisely assessing patient risk. To improve our ability to accurately identify the most aggressive malignancies, we constructed genome-wide survival models using gene expression, copy number, methylation, and mutation data from 10,884 patients with known clinical outcomes. We identified more than 100,000 significant prognostic biomarkers and demonstrate that these genomic features can predict patient outcomes in clinically-ambiguous situations. While adverse biomarkers are commonly believed to represent cancer driver genes and promising therapeutic targets, we show that cancer features associated with shorter survival times are not enriched for either oncogenes or for successful drug targets. Instead, the strongest adverse biomarkers represent widely-expressed housekeeping genes with roles in cell cycle progression, and, correspondingly, nearly all therapies directed against these features have failed in clinical trials. In total, our analysis establishes a rich resource for prognostic biomarker analysis and clarifies the use of patient survival data in preclinical cancer research and therapeutic development.


title: SARS coronavirus vaccines protect against different coronaviruses

abstract:
Although SARS-CoV-2 vaccines have shown efficacy against SARS-CoV-2, it is unclear if they can also protect against other coronaviruses that may infect humans in the future. Here, we show that SARS-CoV-2 vaccination in humans elicits cross-reactive antibodies against other coronaviruses. Our studies in mice demonstrate that SARS-CoV-2 vaccination protects against a common cold coronavirus, and that SARS-CoV-1 vaccination protects against SARS-CoV-2. Similarly, infection with a common cold coronavirus also conferred enhanced protection from subsequent infections with other coronaviruses. Mechanistically, both T cells and antibodies mediated cross-protection. This is the first direct demonstration that coronavirus-specific immunity can confer heterologous protection in vivo, providing a rationale for universal coronavirus vaccines.

HighlightsO_LISARS-CoV-2 vaccination elicits cross-reactive antibody against other coronaviruses in humans.
C_LIO_LICOVID-19 patients generate cross-reactive antibody against other coronaviruses.
C_LIO_LIA SARS-CoV-1 vaccine protects against SARS-CoV-2.
C_LIO_LIPrior coronavirus infections improve immune protection following heterologous coronavirus challenges.
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