title: Is competition for cellular resources a driver of complex trait heritability?

abstract: Most human complex traits are enormously polygenic, with thousands of contributing variants with small effects, spread across much of the genome. These observations raise questions about why so many variants-and so many genes-impact any given phenotype. Here we consider a possible model in which variant effects are due to competition among genes for pools of shared intracellular resources such as RNA polymerases. To this end, we describe a simple theoretical model of resource competition for polymerases during transcription. We show that as long as a gene uses only a small fraction of the overall supply of polymerases, competition with other genes for this supply will only have a negligible effect on variation in the genes expression. In particular, although resource competition increases the proportion of heritability explained by trans-eQTLs, this effect is far too small to account for the roughly 70% of expression heritability thought to be due to trans-regulation. Similarly, we find that competition will only have an appreciable effect on complex traits under very limited conditions: that core genes collectively use a large fraction of the cellular pool of polymerases and their overall expression level is strongly correlated (or anti-correlated) with trait values. Our qualitative results should hold for a wide family of models relating to cellular resource limitations. We conclude that, for most traits, resource competition is not a major source of complex trait heritability.


title: Edison: measuring scaffolding accuracy with edit distance

abstract:
MotivationThe quality of reference genomes critically affects analyses of next generation sequencing experiments. During the construction of the reference genome, contigs are organized into their underlying chromosomes in the scaffolding step. Historically, the quality of scaffolding software has been difficult to evaluate in a systematic and quantitative fashion. To this end, we identified genomic edit distance as a compelling method for evaluating the quality of a scaffold.

ResultsWe present Edison, a Python implementation of the Double Cut and Join (DCJ) edit distance algorithm. Edison calculates the overall accuracy of a given scaffold using a reference genome and also provides scores for characterizing different aspects of the scaffolding accuracy, including grouping, ordering, and orientation. All metrics are calculated on a length-weighted basis, which rewards the correct placement of longer contigs over shorter ones. By creating 1000 random assemblies of the S. cerevisiae genome, we show that our scaffolding accuracy provides a more reliable metric than the commonly used metric, N50. Edison can be used to benchmark new scaffolding algorithms, providing insights into the strengths and weaknesses of each approach.

Availability and ImplementationEdison is available under an MIT license at https://github.com/Noble-Lab/edison.

category: genomics


title: The clinically relevant MTARC1 p.Ala165Thr variant impacts neither the fold nor active site architecture of the human mARC1 protein

abstract: Recent genome-wide association studies (GWAS) have shown a common variant of the human mARC1 protein to be associated with liver disease. Herein, we present the crystal structure of this mARC1 p.Ala165Thr at near-atomic resolution. No relevant differences between the structure of wild type mARC1 and the variant protein are detected.

category: biochemistry


title: Hardware-Efficient Compression of Neural Multi-Unit Activity Using Machine Learning Selected Static Huffman Encoders

abstract:
ObjectiveRecent advances in intracortical brain machine interfaces (iBMIs) have demonstrated the feasibility of using our thoughts; by sensing and decoding neural activity, for communication and cursor control tasks. It is essential that any invasive device is completely wireless so as to remove percutaneous connections and the associated infection risks. However, wireless communication consumes significant power and there are strict heating limits in cortical tissue. Most iBMIs use Multi Unit Activity (MUA) processing, however the required bandwidth can be excessive for large channel counts in mm or submm scale implants. As such, some form of data compression for MUA iBMIs is desirable.

ApproachWe used a Machine Learning approach to select static Huffman encoders that worked together, and investigated a broad range of resulting compression systems. They were implemented in reconfigurable hardware and their power consumption, resource utilization and compression performance measured.

Main ResultsOur design results identified a specific system that provided top performance. We tested it on data from 3 datasets, and found that, with less than 1% behavioural decoding performance reduction from peak, the communication bandwidth was reduced from 1 kb/s/channel to approximately 27 bits/s/channel, using only a Look-Up Table and a 50 ms temporal resolution for threshold crossings. Relative to raw broadband data, this is a compression ratio of 1700-15,000 x and is over an order of magnitude higher than has achieved before. Assuming 20 nJ per communicated bit, the total compression and communication power was between 1.37 and 1.52 W/channel, occupying 246 logic cells and 4 kbit RAM supporting up to 512-channels.

SignificanceWe show that MUA data can be significantly compressed in a hardware efficient manner,  out of the box with no calibration necessary. This can significantly reduce onimplant power consumption and enable much larger channel counts in WI-BMIs. All results, code and hardware designs have been made publicly available.

category: bioengineering


title: Machine-learning algorithm for identifying and predicting amyotrophic lateral sclerosis causal mutations

abstract: We propose a machine learning (ML) method to classify ALS-causative and non-ALS-causative variants based on 24 variables in five different datasets. The proposed ML method classifies the five datasets with very high accuracy. In particular, it predicts the ALS variants with 100 percent accuracy, while its accuracy for the non-ALS variants is up to 99.31 percent. The trained classifier also identifies the nine most influencial mutation assessors that help distinguishing the two classes from each other. They are FATHMM_score, PROVEAN_score, Vest3_score, CADD_phred, DANN_score, meta-SVM_score, phyloP7way_vertebrate, metaLR, and REVEL. Thus, they may be used in future studies in order to reduce the time and cost of collecting data and carrying out experimental tests, as well as in studies with more focus on the recognized assessors.

category: bioinformatics


title: Academic Tracker: Software for Tracking and Reporting Publications Associated with Authors and Grants

abstract: In recent years, United States federal funding agencies, including the National Institutes of Health (NIH) and the National Science Foundation (NSF), have implemented public access policies to make research supported by funding from these federal agencies freely available to the public. Enforcement is primarily through annual and final reports submitted to these funding agencies, where all peer-reviewed publications must be registered through the appropriate mechanism as required by the specific federal funding agency. Unreported and/or incorrectly reported papers can result in delayed acceptance of annual and final reports and even funding delays for current and new research grants. So, its important to make sure every peer-reviewed publication is reported properly and in a timely manner. For large collaborative research efforts, the tracking and proper registration of peer-reviewed publications along with generation of accurate annual and final reports can create a large administrative burden. With large collaborative teams, it is easy for these administrative tasks to be overlooked, forgotten, or lost in the shuffle. In order to help with this reporting burden, we have developed the Academic Tracker software package, implemented in the Python 3 programming language and supporting Linux, Windows, and Mac operating systems. Academic Tracker helps with publication tracking and reporting by comprehensively searching major peer-reviewed publication tracking web portals, including PubMed, Crossref, ORCID, and Google Scholar, given a list of authors. Academic Tracker provides highly customizable reporting templates so information about the resulting publications is easily transformed into appropriate formats for tracking and reporting purposes. The source code and extensive documentation is hosted on GitHub (https://moseleybioinformaticslab.github.io/academic_tracker/) and is also available on the Python Package Index (https://pypi.org/project/academic_tracker) for easy installation.


title: Dimerization processes for light-regulated transcription factor Photozipper visualized by high-speed atomic force microscopy

abstract: Dimerization is critical for transcription factors (TFs) to bind DNA and regulate a wide variety of cellular functions; however, the single-molecular mechanisms remain to be completely elucidated. Here, we used high-speed atomic force microscopy (HS-AFM) to observe the dimerization process for a photoresponsive TF Photozipper (PZ), which consists of light-oxygen-voltage-sensing (LOV) and basic-region-leucine-zipper (bZIP) domain. HS-AFM visualized not only the oligomeric states of PZ molecules forming monomers and dimers under controlled dark-light conditions but also the domain structures within each molecule. Successive AFM movies captured the dimerization process for an individual PZ molecule and the monomer-dimer reversible transition during dark-light cycling. The high-resolution AFM images of the domain structures in PZ molecules demonstrated that the bZIP domain entangled under dark conditions was loosened owing to light illumination and fluctuated around the LOV domain. These observations revealed the role of the bZIP domain in the dimerization processes of a TF.

category: biophysics


title: Mutational Changes and Enhanced Cell Migration during Transformation of Breast Non-tumorigenic Cells to Tumorigenic Cells

abstract: Although cancer stem cells (CSCs) play a major role in tumor initiation and progression, their mechanisms in invasiveness and metastasis are unclear. Tumor microenvironment signals, such as extracellular matrix (ECM) composition, significantly influence cell and tissue behaviors. Unfortunately, these signals are often lost in in vitro cell culture. The current study determines putative CSC populations and contrasts genomic changes in human breast epithelial tumorigenic versus non-tumorigenic cells (both derived from the same normal parental stem cells) and investigates the single-cell migration properties on ECM-mimetic platforms. Whole exome sequencing data indicate that tumorigenic cells have a higher mutation burden than non-tumorigenic cells, and mutations exclusive to tumorigenic cells exhibit higher predictive deleterious scores. ECM-mimetic topography selectively enhances migration speed of tumorigenic cells but not of non-tumorigenic cells. The enhanced migratory ability of tumorigenic cells is lost in conventional two-dimension culture conditions. A wide distribution of tumorigenic single-cell migration speeds suggests heterogeneity in cellular sensing of contact guidance cues. This study identifies mutations acquired during breast tumorigenesis, which can be associated with enhanced invasiveness of breast tumorigenic cells. Results demonstrate that the nanotopographically defined platform can be applied to recapitulate an ECM structure for investigating cellular migration in the simulated tumor microenvironment.

category: cancer biology


title: Planting graphene quantum dots in PEGylated nanoparticles for enhanced and multimodal in vivo imaging of tumor

abstract: Photoluminescent graphene quantum dots (GQDs) have recently attracted considerable attention for biomedical applications owing to the interesting physicochemical and photophysical properties, and prominent biocompatibility and biosafety. However, although much progress has been achieved in therapy and in vitro bioimaging, broad and crucial in vivo fluorescence bioimaging and synergistically working with other nanomedicine are very challenging and limited. Herein, we in situ implanted GQDs in the PEGylated layer of nanoparticles (NPs) via a bottom-up approach to obtain the NPs (core)-GQDs-PEG multifunctional nanoprobe (NPC-GQDs-PEG), which prolonged the blood circulation of GQDs more than four times and increased the tumor accumulation 7~8 times than GQDs used alone. Under assisted by the flexible microscope, the GQDs were successfully used for in vivo real-time monitoring of local NPs pharmacokinetics, in vivo multimodality imaging, and fluorescence imaging-guided tumor surgery. The approach of implanting GQDs in PEGylated nanomedicine and synergistic working provide a new strategy for in vivo biomedical applications of GQDs.


title: Nucleic Acid Adductomics - the Next Generation of Adductomics for Assessing Environmental Health Risk

abstract: The exposome describes the totality of internal and external environmental exposures, across the life course. Components of the exposome have been linked to an increased risk of various, major diseases. To identify the precise nature, and size, of risk, in this complex mixture of exposures, powerful tools are needed to link exposure, cellular consequences, and health/disease. The most biologically informative biomarkers of the exposome should, to varying extents, reflect the dose of the exposure on the body or target organ(s), a subsequent effect on the biological system and, ideally, possess a role in disease. Modification of nucleic acids (NA) is a key consequence of environmental exposures, and while cellular DNA adductomics aims to evaluate the totality to DNA modifications in the genome, an approach which encompasses modifications of all nucleic acids, would be far more comprehensive, and therefore informative. To address this, we propose a cellular and urinary NA adductomics approach for the assessment of both DNA and RNA modifications, including modified (2-deoxy)ribonucleosides (2dN/rN), modified nucleobases (nB), plus: DNA-DNA, RNA-RNA, DNA-RNA, DNA-protein, and RNA-protein crosslinks (DDCL, RRCL, DRCL, DPCL, and RPCL, respectively). Supporting the feasibility of this approach, we presented preliminary, proof-of-principle results, which revealed the presence of over 1,000 modified NA moieties, and at least six types of NA modifications, in a representative, pooled urine from healthy subjects, including modified 2-dN, modified rN, modified nB, DRCL, RRCL and RPCL, many of which were novel/unexpected. We suggest that NA adductomics will provide a more comprehensive approach to the study of nucleic acid modifications, which will facilitate a range of advances, including the identification of novel, unexpected modifications e.g., RNA-RNA, and DNA-RNA crosslinks; key modifications associated with mutagenesis; agent-specific mechanisms; and adductome signatures of key environmental agents, leading to the dissection of the exposome, and its role in human health/disease, across the life course.

category: pharmacology and toxicology


title: In vivo transomic analyses of glucose-responsive metabolism in skeletal muscle reveal core differences between the healthy and obese states

abstract: Metabolic regulation in skeletal muscle is essential for blood glucose homeostasis. Obesity causes insulin resistance in skeletal muscle, leading to hyperglycemia and type 2 diabetes. In this study, we performed multiomic analysis of the skeletal muscle of wild-type (WT) and genetically obese (ob/ob) mice, and constructed regulatory transomic networks for metabolism after oral glucose administration. Our network revealed that metabolic regulation by glucose-responsive metabolites had a major effect on WT mice, especially carbohydrate metabolic pathways. By contrast, in ob/ob mice, much of the metabolic regulation by glucose-responsive metabolites was lost and metabolic regulation by glucose-responsive genes was largely increased, especially in carbohydrate and lipid metabolic pathways. We present some characteristic metabolic regulatory pathways found in central carbon, branched amino acids, and ketone body metabolism. Our transomic analysis will provide insights into how skeletal muscle responds to changes in blood glucose and how it fails to respond in obesity.

category: systems biology


title: Red Knot Stopover Population Size and Migration Ecology at Delaware Bay, USA, 2021

abstract: Red Knots (Calidris canutus rufa) stop at Delaware Bay during northward migration to feed on eggs of horseshoe crabs (Limulus polyphemus). In the late 1990s and early 2000s, the number of Red Knots found at Delaware Bay dramatically declined from ~50,000 to ~13,000. Horseshoe crabs have been harvested for use as bait in eel and whelk fisheries since at least 1990, and some avian conservation biologists hypothesized that harvest levels in the 1990s prevented sufficient refueling for successful migration to the breeding grounds, nesting, and survival for the remainder of the annual cycle. Since 2013, the harvest of horseshoe crabs in the Delaware Bay region has been managed using an Adaptive Resource Management (ARM) framework. The objective of the ARM framework is to manage sustainable harvest of Delaware Bay horseshoe crabs while maintaining ecosystem integrity and supporting Red Knot recovery with adequate stopover habitat for Red Knots and other migrating shorebirds. For annual harvest recommendations, the ARM framework requires annual estimates of horseshoe crab population size and the Red Knot stopover population. We conducted a mark-recapture-resight investigation to estimate the passage population of Red Knots at Delaware Bay in 2021. We used a Bayesian analysis of a Jolly-Seber model, which accounts for turnover in the population and the probability of detection during surveys. The 2021 Red Knot mark-resight dataset included a total of 1,591 individual birds that were recorded at least one during mark-resight surveys at Delaware Bay in 2021. The passage population size in 2021 was estimated at 42,271 (95% credible interval: 35,948 - 55,210). Like 2020, the 2021 population estimate is slightly lower than the 2018 and 2019 estimates. The 2021 population size estimate will inform decision making for harvest recommendations in the next management cycle.

category: ecology


title: Changes in both top-down and bottom-up effective connectivity drive visual hallucinations in Parkinson's disease

abstract: Visual hallucinations are common in Parkinsons disease and are associated with poorer quality of life and higher risk of dementia. An important and influential model that is widely accepted as an explanation for the mechanism of visual hallucinations in Parkinsons disease and other Lewy-body diseases is that these arise due to aberrant hierarchical processing, with impaired bottom-up integration of sensory information and overweighting of top-down perceptual priors within the visual system. This hypothesis has been driven by behavioural data and supported indirectly by observations derived from regional activation and correlational measures using neuroimaging. However, until now, there was no evidence from neuroimaging for differences in causal influences between brain regions measured in patients with Parkinsons hallucinations. This is in part because previous resting-state studies focus on functional connectivity, which is inherently undirected in nature and cannot test hypotheses about directionality of connectivity. Spectral dynamic causal modelling is a Bayesian framework that allows the inference of effective connectivity - defined as the directed (causal) influence that one region exerts on another region - from resting-state functional MRI data. In the current study, we utilise spectral dynamic causal modelling to estimate effective connectivity within the resting-state visual network in our cohort of 15 Parkinsons disease visual hallucinators, and 75 Parkinsons disease non-hallucinators. We find that visual hallucinators display decreased bottom-up effective connectivity from the lateral geniculate nucleus to primary visual cortex and increased top-down effective connectivity from left prefrontal cortex to primary visual cortex and medial thalamus, as compared to non-hallucinators. Importantly, we find that the pattern of effective connectivity is predictive of the presence of visual hallucinations and associated with their severity within the hallucinating group. This is the first study to provide evidence, using resting state effective connectivity, to support a model of aberrant hierarchical predictive processing as the mechanism for visual hallucinations in Parkinsons disease.

category: neuroscience


title: Localized and Distributed Representations of Person Knowledge for Faces

abstract:
Modular neural models of face processing posit that face-associated person-knowledge is localized in, or accessed through, the ventral anterior temporal lobe (vATL). However, some studies have suggested that person-knowledge is more widely distributed within a larger face-processing network that includes the mid-fusiform gyrus ( fusiform face area). Here, we conducted an fMRI study to distinguish whether person-knowledge is localized or distributed by comparing brain responses evoked by synthetic faces, for which participants had learned person-knowledge (biographical facts) and faces for which the subjects had learned only physical facts. After extensive training, participants were cued to recall a particular biographical or physical fact about the upcoming face. In an alternate passive-viewing task, participants were shown the same faces but were not cued to recall biographical or physical facts. Classification analyses (MVPA) were performed on several a priori chosen face-selective regions (ROIs) in the ventral temporal cortex. Within each ROI tested in isolation, MVPA discriminated faces associated with person-knowledge from faces only associated with physical facts. This result is consistent with a distributed model for person-knowledge. However, when tested in a single model to separate shared and unique information, unique information was limited to the left mid-fusiform and vATL posterior (vATL-p) ROIs. Moreover, the feature weights from these two areas showed that only left vATL-p was specialized for processing biographical facts. This latter result was obtained only when these biographical facts were explicitly retrieved in the cueing task. Thus, our results indicate that the left vATL-p represents explicit recall of face-associated person-knowledge.

New & NoteworthyWhether person knowledge for faces is localized in a domain-specific region, vATL, or distributed in many domain-general brain regions, including the mid-fusiform gyrus, is hotly contested. We resolve this debate by using multivariate analyses to partial fMRI signal from different brain regions into unique and shared variance. Our findings show that unique information for person knowledge is found in both the vATL and mid-fusiform but only the vATL represents explicit recall of face-associated person knowledge.


title: Intracellular Energy Controls Dynamics of Stress-induced Ribonucleoprotein Granules

abstract: Energy metabolism and membraneless organelles have been implicated in human diseases including neurodegeneration. How energy stress regulates ribonucleoprotein particles such as stress granules (SGs) is still unclear. Here we identified a unique type of granules formed under energy stress and uncovered the mechanisms by which the dynamics of diverse stress-induced granules are regulated. Severe energy stress induced the rapid formation of energy-associated stress granules (eSGs), whereas moderate energy stress delayed the clearance of conventional SGs. The formation of eSGs or the clearance of conventional SGs was regulated by the mTOR-4EBP1-eIF4E pathway or eIF4A1, involving eIF4F complex assembly or RNA condensation, respectively. In ALS patients neurons or cortical organoids, the eSG formation was enhanced, and conventional SG clearance was impaired. These results reveal a critical role for intracellular energy in the regulation of diverse granules and suggest that an imbalance in these dynamics may contribute to the pathogenesis of relevant diseases.


title: CTLA-4 regulates PD-L1-PD-1 interactions via transendocytosis of CD80

abstract: CTLA-4 and PD-1 are key immune checkpoints that are targeted in the treatment of cancer. Recently it has emerged that there is a physical interaction between the ligands of these pathways (CD80 and PD-L1), which can prevent PD-L1 inhibitory functions. Since CTLA-4 captures and degrades its ligands via transendocytosis, we investigated how transendocytosis of CD80 is impacted by PD-L1 interaction. We find that transendocytosis of CD80 results in a time-dependent recovery of PD-L1 availability that correlates with CD80 removal. Moreover, CD80 transendocytosis is highly specific in that only CD80 is removed, and its heterodimeric PD-L1 partner remains on the APC. We found no evidence that CTLA-4 interactions with CD80 were inhibited by PD-L1, however efficient removal of CD80 required an intact CTLA-4 cytoplasmic domain, distinguishing this process from more general trogocytosis. We also show that simple binding of CTLA-4 to the CD80-PD-L1 heterodimer is insufficient to liberate PD-L1-PD-1 interactions, suggesting that transendocytosis of CD80 is required to effectively control PD-L1-PD-1 interactions.

category: immunology


title: Multiplexed measurement of binding- and neutralizing antibodies to SARS-CoV-2 variants in 12.000 post-vaccine sera

abstract: Diagnostic assays currently used to monitor the efficacy of COVID-19 vaccines measure levels of antibodies to the receptor-binding domain of ancestral SARS-CoV-2 (RBDwt). However, the predictive value for protection against new variants of concern (VOCs) has not been firmly established. Here, we used bead-based arrays and flow cytometry to measure binding of antibodies to spike proteins and receptor-binding domains (RBDs) from VOCs in 12,000 sera. Effects of sera on RBD-ACE2 interactions were measured as a proxy for neutralizing antibodies. The samples were obtained from healthy individuals or patients on immunosuppressive therapy who had received two to four doses of COVID-19 vaccines and from COVID-19 convalescents. The results show that anti-RBDwt titers correlate with the levels of binding- and neutralizing antibodies against the Alpha, Beta, Gamma, Delta, Epsilon and Omicron variants. The benefit of multiplexed analysis lies in the ability to measure a wide range of anti-RBD titers using a single dilution of serum for each assay. The reactivity patterns also yield an internal reference for neutralizing activity and binding antibody units per milliliter (BAU/ml). Results obtained with sera from vaccinated healthy individuals and patients confirmed and extended results from previous studies on time-dependent waning of antibody levels and effects of immunosuppressive agents. We conclude that anti-RBDwt titers correlate with levels of neutralizing antibodies against VOCs and propose that our method may be implemented to enhance the precision and throughput of immunomonitoring.


title: Titers of antibodies the receptor-binding domain (RBD) of ancestral SARS-CoV-2 are predictive for levels of neutralizing antibodies to multiple variants


title: Genome-wide identification of the LexA-mediated DNA damage response in Streptomyces venezuelae

abstract:
DNA damage triggers a widely conserved stress response in bacteria called the SOS response that involves two key regulators, the activator RecA and the transcriptional repressor LexA. Despite the wide conservation of the SOS response, the number of genes controlled by LexA varies considerably between different organisms. The filamentous soil-dwelling bacteria of the genus Streptomyces contain LexA and RecA homologs but their roles in Streptomyces have not been systematically studied.

Here, we demonstrate that RecA and LexA are required for the survival of Streptomyces venezuelae during DNA damaging conditions and for normal development during unperturbed growth. Monitoring the activity of a fluorescent recA promoter fusion and LexA protein levels revealed that the activation of the SOS response is delayed in S. venezuelae. By combining global transcriptional profiling and ChIP-seq analysis, we determined the LexA regulon and defined the core set of DNA damage repair genes that are expressed in response to treatment with the DNA alkylating agent mitomycin C. Our results show that DNA damage-induced degradation of LexA results in the differential regulation of LexA target genes. Using Surface Plasmon Resonance, we further confirm the LexA DNA binding motif (SOS box) and demonstrate that LexA displays tight but distinct binding affinities to its target promoters, indicating a graded response to DNA damage.

category: microbiology


title: A Hepatitis C virus genotype 1b post transplant isolate with high replication efficiency in cell culture and its adaptation to infectious virus production in vitro and in vivo

abstract:
Hepatitis C virus (HCV) is highly diverse and grouped into eight genotypes (gts). Infectious cell culture models are limited to a few subtypes, that do not include the highly prevalent gt1b, hampering the development of prophylactic vaccines. A consensus gt1b genome (termed GLT1) was generated from an HCV infected liver-transplanted patient. GLT1 replicated to an outstanding efficiency in Huh7 cells upon SEC14L2 expression, by use of replication enhancing mutations or with a previously developed inhibitor-based regimen. RNA replication levels almost reached JFH-1, but full-length genomes failed to produce detectable amounts of infectious virus. Long-term passaging led to the adaptation of a genome carrying 21 mutations and concomitant production of high levels of transmissible infectivity (GLT1cc). During the adaptation, GLT1 spread in the culture even in absence of detectable amounts of free virus, but cell-to-cell spreading efficiency was not higher as in other isolates like JFH-1. Mechanistically, genome replication and particle production efficiency were enhanced by adaptation, while cell entry competence of HCV pseudoparticles was not affected. Furthermore, GLT1cc retained the ability to replicate in human liver chimeric mice, which was critically dependent on a mutation in domain 3 of nonstructural protein NS5A. Over the course of infection, only one mutation in the surface glycoprotein E2 consistently reverted to wildtype, facilitating assembly in cell culture but potentially affecting CD81 interaction in vivo.

Overall, GLT1cc is the first efficient gt1b infectious cell culture model, paving the road to a rationale-based establishment of new infectious HCV isolates and represents an important novel tool for the development of prophylactic HCV vaccines.

Author summaryChronic HCV infections remain an important global health issue, despite the availability of highly efficient therapies. So far no protective vaccine is available, which is in part due to the high divergence of HCV variants and the limited possibly to mirror this genetic diversity in cell culture. It has been proven particularly difficult to grow infectious virus in cell culture, requiring extensive adaptation with multiple mutations, which in turn affect infectivity of the adapted variants in vivo. Here we have isolated a genotype 1b variant from a very high titer serum of a patient after liver transplantation (German Liver Transplant 1, GLT1), showing an outstanding genome replication efficiency in cultured hepatoma cells. We were able to adapt this isolate to production of infectious virus, therefore generating the first efficient full-replication cycle cell culture model for highly prevalent HCV genotype 1b. Despite multiple mutations required, adapted GLT1 was still infectious in vivo. GLT1 therefore is not only an important novel development facilitating future efforts in vaccine development. It also provides novel perspectives towards our understanding how liver transplantation drives the evolution of viral isolates with high replication capacity, which might contribute to direct pathogenesis of HCV infection.


title: Neutralization of Omicron BA.1, BA.2, and BA.3 SARS-CoV-2 by 3 doses of BNT162b2 vaccine

abstract: The newly emerged Omicron SARS-CoV-2 has 3 distinct sublineages: BA.1, BA.2, and BA.3. BA.1 accounts for the initial surge and is being replaced by BA.2, whereas BA.3 is at a low prevalence at this time. Here we report the neutralization of BNT162b2-vaccinated sera (collected at 1 month after dose 3) against the three Omicron sublineages. To facilitate the neutralization testing, we engineered the complete BA.1, BA.2, or BA.3 spike into an mNeonGreen USA-WA1/2020 SRAS-CoV-2. All BNT162b2-vaccinated sera neutralized USA-WA1/2020, BA.1-, BA.2-, and BA.3-spike SARS-CoV-2s with titers of >20; the neutralization geometric mean titers (GMTs) against the four viruses were 1211, 336, 300, and 190, respectively. Thus, the BA.1-, BA.2-, and BA.3-spike SARS-CoV-2s were 3.6-, 4.0-, and 6.4-fold less efficiently neutralized than the USA-WA1/2020, respectively. Our data have implications in vaccine strategy and understanding the biology of Omicron sublineages.


title: Exploring a novel genomic safe-haven site in the human pathogenic mould Aspergillus fumigatus.

abstract: Aspergillus fumigatus is the most important airborne fungal pathogen and allergen of humans causing high morbidity and mortality worldwide. The factors that govern pathogenicity of this organism are multi-factorial and are poorly understood. Molecular tools to dissect the mechanisms of pathogenicity in A. fumigatus have improved significantly over the last 20 years however many procedures have not been standardised for A. fumigatus. Here, we present a new genomic safe-haven locus at the site of an inactivated transposon, named SH-aft4, which can be used to insert DNA sequences in the genome of this fungus without impacting its phenotype. We show that we are able to effectively express a transgene construct from the SH-aft4 and that natural regulation of promoter function is conserved at this site. Furthermore, the SH-aft4 locus is highly conserved in the genome of a wide range of clinical and environmental isolates including the isolates commonly used by many laboratories CEA10, Af293 and ATCC46645, allowing a wide range of isolates to be manipulated. Our results show that the aft4 locus can serve as a site for integration of a wide range of genetic constructs to aid functional genomics studies of this important human fungal pathogen.


title: A unified in vitro to in vivo fluorescence lifetime screening platform yields amyloid β aggregation inhibitors

abstract: Inhibiting the aggregation of amyloid {beta} (1-42) is a promising strategy for the development of disease-modifying Alzheimers disease therapeutics. To date, however, no sufficiently efficacious inhibitors have been identified, despite the best efforts of >200 advanced drug development campaigns. This failure can be attributed to limitations in current compound screening and in vivo validation assays. Here, we report an in vitro to in vivo screening platform based on the use of a fluorescence lifetime aggregation sensor. The microfluidic "nanoFLIM" assay developed circumvents issues that plague conventional assays, such as lack of reproducibility, high cost and artefactual false read-outs. The fluorescence lifetime sensor can also dynamically monitor peptide aggregation in cellular and Caenorhabditis elegans disease models, providing directly comparable aggregation kinetics, which is not achievable by any other method. The power of this unified system for accelerating hit-to-lead strategies, lowering attrition rates and expediting in vivo screening, was demonstrated with a pilot screening campaign of 445 compounds, revealing a new inhibitor that can inhibit amyloid {beta} self-assembly in vitro as well as in cellular and whole organism disease models.

category: molecular biology


title: Distinct regulation of Hox genes by Polycomb Group genes in a crustacean

abstract:
Non-insect crustaceans exhibit tremendous body plan diversity. The evolution of diverse patterns of Hox gene expression has been implicated as a primary driver of body plan evolution between crustacean groups, but the mechanisms underlying Hox regulatory evolution remain unknown. We identify Polycomb and Trithorax Group proteins, crucial for proper Hox regulation across bilaterians, in the genome of the amphipod crustacean Parhyale hawaiensis, and demonstrate their essential functions in crustacean Hox regulation and embryonic development using CRISPR-Cas9 mutagenesis. Examination of Hox misexpression patterns between individual Hox genes with respect to timing, tissue, and PcG mutant gene in mutant embryos reveals that each crustacean Hox gene follows its own idiosyncratic regulatory mechanism. These results suggest a distinct regulation of Hox genes that may have enabled crustacean body plan evolution.

Primary Findings- The genome of the amphipod crustacean Parhyale hawaiensis contains all core Polycomb Group (PcG) and Trithorax Group (TrxG) proteins

- CRISPR-Cas9 mutagenesis of PcG proteins induces homeotic transformations and misexpression of Hox genes that differ from similar experiments in insects

- PcG knockout embryos show proper initiation of Hox expression boundaries at early developmental stages

- Each of the three posterior Hox genes in Parhyale displays distinct patterns of misexpression in response to PcG knockout

- Hox regulation appears to occur via different mechanisms in the nervous system vs. limbs

- PcG phenotypes reveal the potential for distinct layers of Hox regulation in crustaceans

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category: developmental biology


title: Sperm mosaicism predicts transmission of de novo mutations to human blastocysts

abstract: De novo mutations underlie individually rare but collectively common pediatric congenital disorders. Some of these mutations can also be detected in tissues and from cells in a parent, where their abundance and tissue distribution can be measured. We previously reported that a subset of these mutations is detectable in sperm from the father, predicted to impact the health of offspring. Here, in three independent couples undergoing in vitro fertilization, we first assessed male gonadal mosaicism, then assessed the transmission of the mutations to their preimplantation blastocysts. We found an overall predictable transmission but slight under-transmission of mutations to blastocysts based upon measured mutational abundance in sperm, and we replicated this conclusion in an independent family-based cohort. Therefore, unbiased preimplantation genetic testing for gonadal mosaicism may represent a feasible approach to reduce the transmission of potentially harmful de novo mutations, which could help to reduce their impact on miscarriage and pediatric disease.

category: genetics


title: ACSF2: A MEDIUM-CHAIN ACYL-CoA SYNTHETASE WITH A POTENTIAL ROLE IN NEURONAL DIFFERENTIATION

abstract: By activating fatty acids to their CoA derivatives, acyl-CoA synthetases (ACS) play an essential role in fatty acid metabolism. We previously identified ACSF2 as an ACS that was phylogenetically distinct from known families of short-chain, medium-chain, long-chain, very long-chain, and bubblegum ACSs. Functionally, ACSF2 preferentially activated medium-chain fatty acids. In this work, we provide further characterization of this unique ACS. ACSF2 mRNA expression was found in most tissues, although immunohistochemical analysis revealed differences in protein expression between various cell types in each tissue. Endogenous ACSF2 was found in the Golgi region in Neuro2a and P19 cells, and disruption of the Golgi in Neuro2a cells with nocodazole disrupted ACSF2 localization. In contrast, MA-10, HepG2, and skin fibroblasts had a mitochondrial ACSF2 localization. ACSF2 activated saturated fatty acids containing 6 to 10 carbons when overexpressed in COS-1 cells. The Kmapp for C10:0 was 24.4 M and Vmaxapp was 385 nmol/20min/mg COS cell protein. Knockdown by RNA interference revealed that ACSF2 was responsible for most of the medium-chain ACS activity in Neuro2a cells. A lysine residue critical for activity in bacterial short-chain ACSs was found in ACSF2, and mutation of this residue to alanine abolished enzyme activity. Neurite outgrowth results when Neuro2a cells are induced to differentiate with retinoic acid, and ACSF2 migrated to nodes and points of neurite-neurite contact along with the presynaptic marker, synaptophysin. ACSF2-deficient Neuro2a cells showed significantly blunted neurite outgrowth in response to retinoic acid. These results suggest that this medium-chain ACS may play an important role in neuronal development.


title: Genetically engineered MRI-trackable extracellular vesicles as SARS-CoV-2 mimetics for mapping ACE2 binding in vivo

abstract: The elucidation of viral-receptor interactions and an understanding of virus-spreading mechanisms are of great importance, particularly in the era of pandemic. Indeed, advances in computational chemistry, synthetic biology, and protein engineering have allowed precise prediction and characterization of such interactions. Nevertheless, the hazards of the infectiousness of viruses, their rapid mutagenesis, and the need to study viral-receptor interactions in a complex in vivo setup, call for further developments. Here, we show the development of biocompatible genetically engineered extracellular vesicles (EVs) that display the receptor binding domain (RBD) of SARS-CoV-2 on their surface as coronavirus mimetics (EVsRBD). Loading EVsRBD with iron oxide nanoparticles makes them MRI-visible, and thus, allows mapping of the binding of RBD to ACE2 receptors non-invasively in live subjects. Importantly, the proposed mimetics can be easily modified to display the RBD of SARS-CoV-2mutants, namely Delta and Omicron, allowing rapid screening of newly raised variants of the virus. The proposed platform thus shows relevance and cruciality in the examination of quickly evolving pathogenic viruses in an adjustable, fast, and safe manner.


title: The interplay between lncRNAs, RNA-binding proteins and viral genome during SARS-CoV-2 infection reveals strong connections with regulatory events involved in RNA metabolism and immune response.

abstract:
Viral infections are complex processes based on an intricate network of molecular interactions. The infectious agent hijacks components of the cellular machinery for its profit, circumventing the natural defense mechanisms triggered by the infected cell. The successful completion of the replicative viral cycle within a cell depends on the function of viral components versus the cellular defenses. Non-coding RNAs (ncRNAs) are important cellular modulators, either promoting or preventing the progression of viral infections. Among these ncRNAs, the long non-coding RNA (lncRNA) family is especially relevant due to their intrinsic functional properties and ubiquitous biological roles. Specific lncRNAs have been recently characterized as modulators of the cellular response during infection of human host cells by single stranded RNA viruses. However, the role of host lncRNAs in the infection by human RNA coronaviruses such as SARS-CoV-2 remains uncharacterized. In the present work, we have performed a transcriptomic study of a cohort of patients with different SARS-CoV-2 viral load. Our results revealed the existence of a SARS-CoV-2 infection-dependent pattern of transcriptional up-regulation in which specific lncRNAs are an integral component. To determine the role of these lncRNAs, we performed a functional correlation analysis complemented with the study of the validated interactions between lncRNAs and RNA-binding proteins (RBPs). This combination of in silico functional association studies and experimental evidence allowed us to identify a lncRNA signature composed of six elements - NRIR, BISPR, MIR155HG, FMR1-IT1, USP30-AS1, and U62317.2 - associated with the regulation of SARS-CoV-2 infection. We propose a competition mechanism between the viral RNA genome and the regulatory lncRNAs in the sequestering of specific RBPs that modulates the interferon response and the regulation of RNA surveillance by nonsense-mediated decay (NMD).

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org.highwire.dtl.DTLVardef@4368c9org.highwire.dtl.DTLVardef@1948201org.highwire.dtl.DTLVardef@e31fd9org.highwire.dtl.DTLVardef@1400805_HPS_FORMAT_FIGEXP  M_FIG C_FIG Graphical abstractModel of interactions among lncRNA and cognate RNA-binding proteins in SARS-CoV-2 infection. According to our model, the viral genome can establish direct interactions with three core proteins (DDX3X, UPF1 and IGF2BP2) involved in mRNA metabolism and regulation of the interferon response, which are also components of a SARS-CoV-2 lncRNA-centered regulatory network. The competition between viral RNA and lncRNAs could act as a counteracting factor for the normal function of homeostatic lncRNA-centered regulatory networks, contributing to viral progression and replication. Black arrows depict physical interactions between network components; red arrows represent functional relationships.


title: Transient Water Wires Mediate Selective Proton Conduction in Designed Channel Proteins

abstract: Selective proton transport through proteins is essential for forming and utilizing proton gradients in cells. Protons are conducted along hydrogen-bonded "wires" of water molecules and polar sidechains, which, somewhat surprisingly, are often interrupted by dry apolar stretches in the conduction pathways inferred from static protein structures. We hypothesize that protons are conducted through such dry spots by forming transient water wires. To test this hypothesis, we used molecular dynamics simulations to design transmembrane channels with stable water pockets interspersed by apolar segments capable of forming flickering water wires. The minimalist designed channels conduct protons at rates similar to viral proton channels, and they are at least 106-fold more selective for H+ over Na+. These studies inform mechanisms of biological proton conduction and principles for engineering proton-conductive materials.


title: Maximizing the Anti-tumor Potential of Immune Checkpoint Blockade through Modulation of Myeloid-specific CXCL16 and STAT1 Signaling

abstract:
Sensitivity to immune checkpoint blockades (ICB) depends on the overall balance of immunogenic and immunosuppressive signals in the tumor immune microenvironment (TIME). Chemotherapy as an immunostimulatory strategy showed potential in improving ICBs clinical efficacy. Yet, evolution of highly plastic tumor-associated myeloid cells hinders ICBs potential to reach its full therapeutic potential. In this study, we leveraged single-cell transcriptomic and trajectory analyses to delineate TIME dynamics after chemotherapy priming. We found that metronomic chemotherapy (MCT) treatment led to an accelerated T cell exhaustion through CXCL16-mediated recruitment of peripheral immature myeloid cells and expansion of STAT1-driven PD-L1 expressing myeloid cells. Inhibiting STAT1 signaling in MCT-primed breast cancer relieved T cell exhaustion and significantly enhanced the efficacy of anti-PD-1 ICB treatment. Our study leveraged single-cell analyses to dissect the dynamics of breast cancer TIME and provides a pre-clinical rationale to translate the anti-STAT1 plus anti-PD-1 combinatorial immunotherapy regimen to maximize ICBs efficacy.

Manuscript SummarySingle-cell analyses on low dose chemotherapy primed breast tumor-associated immune cells demonstrates a parallel coexistence of immunogenic and immunosuppressive myeloid cell subsets. Modulating STAT1 signaling in the tumor microenvironment fine-tunes immunogenic and immunosuppressive balance and maximizes the anti-PD-1 immunotherapy efficacy in chemotherapy-primed breast cancer.


title: A complete MAPK cascade, a calmodulin, and a protein phosphatase act downstream of CRK receptor kinases and regulate Arabidopsis innate immunity

abstract: Mitogen-activated protein kinase (MAPK) cascades are critical signal transduction modules in stress responses, but how their composition and mode of activation induces a stress response is poorly understood. We showed in Arabidopsis that CRK21, a cysteine-rich receptor-like protein kinase (CRK), phosphorylates MAPK kinase kinase 20 (MKKK20) and thus directly activates a novel MAPK cascade, consisting of MKKK20, the MAPK kinase MKK3, and the MAPK MPK6. Furthermore, the protein phosphatase PP2C76 and the calmodulin CaM7 were identified as negative and positive modulators of the cascade, respectively. Loss-of-function in components of the MAPK cascade or in CaM7 led to susceptibility to the bacterial pathogen Pseudomonas syringae and the fungal pathogen Botrytis cinerea. In contrast, loss-of-function of PP2C76 as well as transient overexpression of the genes in the MAPK cascade and CaM7 conferred resistance to the pathogens. Moreover, seven additional CRKs interacted with MKKK20 in vivo, and four of these were highly expressed after inoculation with P. syringae. In summary, our findings demonstrate that the novel CRK21-MKKK20-MKK3-MPK6 signaling pathway functions in immunity to fungal and bacterial pathogens and that CRKs may function in directly activating MKKKs.

category: plant biology


title: A SARS-CoV-2 Spike Ferritin Nanoparticle Vaccine is Protective and Promotes a Strong Immunological Response in the Cynomolgus Macaque Coronavirus Disease 2019 (COVID-19) Model

abstract: The COVID-19 pandemic has had a staggering impact on social, economic, and public health systems worldwide. Vaccine development and mobilization against SARS-CoV-2 (the etiologic agent of COVID-19) has been rapid. However, novel strategies are still necessary to slow the pandemic, and this includes new approaches to vaccine development and/or delivery, which improve vaccination compliance and demonstrate efficacy against emerging variants. Here we report on the immunogenicity and efficacy of a SARS-CoV-2 vaccine comprised of stabilized, pre-fusion Spike protein trimers displayed on a ferritin nanoparticle (SpFN) adjuvanted with either conventional aluminum hydroxide or the Army Liposomal Formulation QS-21 (ALFQ) in a cynomolgus macaque COVID-19 model. Vaccination resulted in robust cell-mediated and humoral responses and a significant reduction of lung lesions following SARS-CoV-2 infection. The strength of the immune response suggests that dose sparing through reduced or single dosing in primates may be possible with this vaccine. Overall, the data support further evaluation of SpFN as a SARS-CoV-2 protein-based vaccine candidate with attention to fractional dosing and schedule optimization.


title: An engineered ACE2 decoy receptor can be administered by inhalation and potently targets the BA.1 and BA.2 omicron variants of SARS-CoV-2

abstract: Monoclonal antibodies targeting the SARS-CoV-2 spike (S) glycoprotein neutralize infection and are efficacious for the treatment of mild-to-moderate COVID-19. However, SARS-CoV-2 variants have emerged that partially or fully escape monoclonal antibodies in clinical use. Notably, the BA.2 sublineage of B.1.1.529/omicron escapes nearly all monoclonal antibodies currently authorized for therapeutic treatment of COVID-19. Decoy receptors, which are based on soluble forms of the host entry receptor ACE2, are an alternative strategy that broadly bind and block S from SARS-CoV-2 variants and related betacoronaviruses. The high-affinity and catalytically active decoy sACE22.v2.4-IgG1 was previously shown to be effective in vivo against SARS-CoV-2 variants when administered intravenously. Here, the inhalation of sACE22.v2.4-IgG1 is found to increase survival and ameliorate lung injury in K18-hACE2 transgenic mice inoculated with a lethal dose of the virulent P.1/gamma virus. Loss of catalytic activity reduced the decoys therapeutic efficacy supporting dual mechanisms of action: direct blocking of viral S and turnover of ACE2 substrates associated with lung injury and inflammation. Binding of sACE22.v2.4-IgG1 remained tight to S of BA.1 omicron, despite BA.1 omicron having extensive mutations, and binding exceeded that of four monoclonal antibodies approved for clinical use. BA.1 pseudovirus and authentic virus were neutralized at picomolar concentrations. Finally, tight binding was maintained against S from the BA.2 omicron sublineage, which differs from S of BA.1 by 26 mutations. Overall, the therapeutic potential of sACE22.v2.4-IgG1 is further confirmed by inhalation route and broad neutralization potency persists against increasingly divergent SARS-CoV-2 variants.


title: A Rapid, High Throughput, Viral Infectivity Assay using Automated Brightfield Microscopy with Machine Learning

abstract: Infectivity assays are essential for the development of viral vaccines, antiviral therapies and the manufacture of biologicals. Traditionally, these assays take 2-7 days and require several manual processing steps after infection. We describe an automated assay (AVIA), using machine learning (ML) and high-throughput brightfield microscopy on 96 well plates that can quantify infection phenotypes within hours, before they are manually visible, and without sample preparation. ML models were trained on HIV, influenza A virus, coronavirus 229E, vaccinia viruses, poliovirus, and adenoviruses, which together span the four major categories of virus (DNA, RNA, enveloped, and non-enveloped). A sigmoidal function, fit to virus dilution curves, yielded an R2 higher than 0.98 and a linear dynamic range comparable to or better than conventional plaque or TCID50 assays. Because this technology is based on sensitizing AIs to specific phenotypes of infection, it may have potential as a rapid, broad-spectrum tool for virus identification.


title: Analytic representation of inhomogeneous-resolution maps of three-dimensional scalar fields

abstract:
Refinement of macromolecular atomic models versus experimental maps in cryo-electron microscopy and crystallography is a critical step in structure solution. For an appropriate comparison, model maps should mimic imperfections of the experimental ones, mainly atomic disorder and its limited resolution, often inhomogeneous over the molecule. We construct these model maps as a sum of atomic contributions expressed through a specially designed function describing a solitary spherical wave. Thanks to this function, atomic contributions analytically depend on both an atomic disorder and the local resolution, a value associated now with each atom. Such fully analytic dependence of inhomogeneous-resolution map values on model parameters permits an efficient refinement of all these parameters together and, beyond structural biology, opens a way to solve similar problems in other research domains.

One-Sentence SummaryAn analytic decomposition of 3D-oscillating functions results in efficient tools to calculate maps and refine atomic models.


title: A widely applicable and cost-effective method for general and specific RNA-protein complex isolation

abstract: Despite important methodological advances made in the past few years, a widely applicable, cost-effective and easily scalable procedure that can be routinely used to isolate ribonucleoprotein complexes (RNPs) remains elusive. We describe a versatile method that connects aspects of existing methods in a workflow optimized to reach the above goals and called it "Silica-based Acidic Phase Separation (SAPS)-capture". To validate the method, the 18S rRNP of S. cerevisiae was captured. To illustrate its applicability, we isolated a repertoire of RNPs in A. thaliana. This procedure can provide the community with a powerful tool to advance the study of ribonomes and RNPs in any organism or tissue type.


title: GLOBAL HOST RESPONSES TO THE MICROBIOTA AT SINGLE CELL RESOLUTION IN GNOTOBIOTIC ZEBRAFISH

abstract:
Resident microbes are a feature of vertebrate animals that influence diverse aspects of their biology from tissue development to metabolism. Here we describe transcriptional responses to the microbiota across all the cells of a model developing vertebrate, the larval zebrafish. By performing single cell transcriptomic analysis of whole germ free and conventionalized larvae, we show that the impacts of the microbiota are sensed by all major organ systems but that responses are highly specific to different cell types. The presence of microbiota stimulates the expansion of progenitor-like cells in epithelial tissues and increases proliferation gene expression in progenitor-like cell populations of the immune and nervous systems. Across many cell types, including enterocytes, immune cells, and neurons, the microbiota upregulates expression of genes involved in microbial responses, cell type-specific activities, and cell type-specific deployment of ATP metabolism genes. These combined transcriptional patterns demonstrate how the microbiota simultaneously modulate cellular immune and metabolic programs. The impacts of the microbiota on tissue development are illustrated by the exocrine pancreas, which in the absence of the microbiota is smaller and composed of uniformly differentiated acinar cells. The presence of the microbiota results in exocrine pancreas enlargement and heterogeneous cellular expression of digestive enzyme and secretion genes, demonstrating how the microbiota promotes plasticity in tissue development and function. This single cell transcriptional dataset demonstrates the impacts of the microbiota on vertebrate development across the body and provides a foundation for dissecting cell type specific responses to microbial consortia members or molecules.

SummaryAnimal development proceeds in the presence of intimate microbial associations, but the extent to which different host cells across the body respond to resident microbes remains to be fully explored. Using the vertebrate model organism, the larval zebrafish, we assessed transcriptional responses to the microbiota across the entire body at single cell resolution. We find that cell types across the body, not limited to tissues at host-microbe interfaces, respond to the microbiota. Responses are cell-type specific, but across many tissues the microbiota enhances cell proliferation, increases metabolism, and stimulates a diversity of cellular activities, revealing roles for the microbiota in promoting developmental plasticity. This work provides a resource for exploring transcriptional responses to the microbiota across all cell types of the vertebrate body and generating new hypotheses about the interactions between vertebrate hosts and their microbiota.


title: Dysregulated H19/Igf2 expression disrupts cardiac-placental axis during development of Silver Russell Syndrome-like mouse models

abstract: Dysregulation of the imprinted H19/IGF2 locus can lead to Silver-Russell Syndrome (SRS) in humans. However, the mechanism of how abnormal H19/IGF2 expression contributes to various SRS phenotypes remains unclear, largely due to incomplete understanding of the developmental functions of these two genes. We previously generated a mouse model with humanized H19/IGF2 ICR (hIC1) on the paternal allele that exhibited H19/Igf2 dysregulation together with SRS-like growth restriction and perinatal lethality. Here we dissect the role of H19 and Igf2 in cardiac and placental development utilizing multiple mouse models with varying levels of H19 and Igf2. We report severe cardiac defects such as ventricular septal defects (VSDs) and thinned myocardium, placental anomalies including thrombosis and vascular malformations, together with growth restriction in mouse embryos that correlated with the extent of H19/Igf2 dysregulation. Transcriptomic analysis using cardiac endothelial cells of these mouse models shows that H19/Igf2 dysregulation disrupts pathways related to extracellular matrix (ECM) and proliferation of endothelial cells. Our work links the heart and placenta through regulation by H19 and Igf2, demonstrating that accurate dosage of both H19 and Igf2 is critical for normal embryonic development, especially related to the cardiac-placental axis.


title: Finding the strongest gene drive: Simulations reveal unexpected performance differences between Anopheles homing suppression drive candidates

abstract: Recent experiments have produced several Anopheles gambiae homing gene drives that disrupt female fertility genes, thereby eventually inducing population collapse. Such drives may be highly effective tools to combat malaria. One such homing drive, based on the zpg promoter driving CRISPR/Cas9, was able to eliminate a cage population of mosquitoes. A second version, purportedly improved upon the first by incorporating an X-shredder element (which biases inheritance towards male offspring), was similarly successful. Here, we re-analyze the data of each of these gene drives and suggest an alternative interpretation of their performance. We assess each suppression drive within an individual-based simulation framework that models mosquito population dynamics in continuous space. We find that the combined homing/X-shredder drive is actually less effective at population suppression within the context of our mosquito population model. In particular, the combined drive often fails to completely suppress the population, instead resulting in an unstable equilibrium between drive and wild-type alleles. By contrast, otherwise similar drives based on the nos promoter may prove to be more promising candidates for future development due to potentially superior performance.


title: Identification of consensus hairpin loop structure among the negative sense sub-genomic RNAs of SARS-CoV-2

abstract: SARS-CoV-2 is the causative agent of worldwide pandemic disease COVID-19. SARS-CoV-2 bears positive sense RNA genome, that have organized and complex pattern of replication/transcription process including the generation of subgenomic RNAs. Transcription regulatory sequences (TRS) have important role in the pausing of replication/transcription and generation of subgenomic RNAs. In the present bioinformatics analysis a consensus secondary structure was identified among negative sense subgenomic RNAs at the adjacent of initiation codon. This study proposed that consensus structured domain could involve in mediating the long pausing of replication/transcription complex and responsible for subgenomic RNA production.


title: Unique molecular signatures sustained in circulating monocytes and regulatory T cells in Convalescent COVID-19 patients

abstract: Over two years into the COVID-19 pandemic, the human immune response to SARS-CoV-2 during the active disease phase has been extensively studied. However, the long-term impact after recovery, which is critical to advance our understanding SARS-CoV-2 and COVID-19-associated long-term complications, remains largely unknown. Herein, we characterized multi-omic single-cell profiles of circulating immune cells in the peripheral blood of 100 patients, including covenlesent COVID-19 and sero-negative controls. The reduced frequencies of both short-lived monocytes and long-lived regulatory T (Treg) cells are significantly associated with the patients recovered from severe COVID-19. Consistently, sc-RNA seq analysis reveals seven heterogeneous clusters of monocytes (M0-M6) and ten Treg clusters (T0-T9) featuring distinct molecular signatures and associated with COVID-19 severity. Asymptomatic patients contain the most abundant clusters of monocyte and Treg expressing high CD74 or IFN-responsive genes. In contrast, the patients recovered from a severe disease have shown two dominant inflammatory monocyte clusters with S100 family genes: S100A8 & A9 with high HLA-I whereas S100A4 & A6 with high HLA-II genes, a specific non-classical monocyte cluster with distinct IFITM family genes, and a unique TGF-{beta} high Treg Cluster. The outpatients and seronegative controls share most of the monocyte and Treg clusters patterns with high expression of HLA genes. Surprisingly, while presumably short-ived monocytes appear to have sustained alterations over 4 months, the decreased frequencies of long-lived Tregs (high HLA-DRA and S100A6) in the outpatients restore over the tested convalescent time (>= 4 months). Collectively, our study identifies sustained and dynamically altered monocytes and Treg clusters with distinct molecular signatures after recovery, associated with COVID-19 severity.


title: Cells with Stochastically Increased Methyltransferase to Restriction Endonuclease Ratio Provide an Entry for Bacteriophage into Protected Cell Population

abstract: The action of type II restriction-modification (RM) systems depends on restriction endonuclease (REase), which cleaves foreign DNA at specific sites, and methyltransferase (MTase), which protects host genome from restriction by methylating the same sites. We show that protection from phage infection increases as the copy number of plasmids carrying the Esp1396l RM system is increased. However, since increased plasmid copy number leads to both increased absolute intracellular REase and MTase levels and decreased MTase to REase ratio, it is impossible to determine which factor determines resistance/susceptibility to infection. By controlled expression of Esp1396I MTase or REase genes in cells carrying the Esp1396I system, we show that a shift in the MTase to REase ratio caused by overproduction of MTase or REase leads, respectively, to decreased or increased protection from infection. Consistently, due to stochastic variation of MTase and REase amount in individual cells, bacterial cells that are productively infected by bacteriophage have significantly higher MTase to REase ratios than cells that ward off the infection. Our results suggest that cells with transiently increased MTase to REase ratio at the time of infection serve as entry points for unmodified phage DNA into protected bacterial populations.


title: Mosaic RBD nanoparticles protect against multiple sarbecovirus challenges in animal models

abstract: To combat future SARS-CoV-2 variants and spillovers of SARS-like betacoronaviruses (sarbecoviruses) threatening global health, we designed mosaic nanoparticles presenting randomly-arranged sarbecovirus spike receptor-binding domains (RBDs) to elicit antibodies against conserved/relatively-occluded, rather than variable/immunodominant/exposed, epitopes. We compared immune responses elicited by mosaic-8 (SARS-CoV-2 and seven animal sarbecoviruses) and homotypic (only SARS-CoV-2) RBD-nanoparticles in mice and macaques, observing stronger responses elicited by mosaic-8 to mismatched (not on nanoparticles) strains including SARS-CoV and animal sarbecoviruses. Mosaic-8 immunization showed equivalent neutralization of SARS-CoV-2 variants including Omicron and protected from SARS-CoV-2 and SARS-CoV challenges, whereas homotypic SARS-CoV-2 immunization protected only from SARS-CoV-2 challenge. Epitope mapping demonstrated increased targeting of conserved epitopes after mosaic-8 immunization. Together, these results suggest mosaic-8 RBD-nanoparticles could protect against SARS-CoV-2 variants and future sarbecovirus spillovers.


title: High resolution parallel sequencing reveals multi-strain Campylobacter in broiler chicken flocks testing 'negative' by conventional culture methods: implications for control of Campylobacter infection.

abstract: Contaminated chicken meat is a major source of human Campylobacteriosis and rates of infection remain high, despite efforts to limit the colonisation of broiler (meat) chicken flocks on farms. Using conventional testing methods of culture or qPCR, Campylobacter is typically detected amongst broiler flocks from 3 weeks of age, leading to the assumption that infection is introduced horizontally into chicken rearing houses at this time. In this study, we use parallel sequencing of a fragment of the Campylobacter outer membrane protein, encoded by the porA gene, to test for presence of Campylobacter DNA amongst fresh faecal samples collected from broiler flocks aged 23-28 days. Campylobacter DNA was detected in all of the 290 samples tested using the porA target, and in 48% of samples using 16S bacterial profiling, irrespective of whether or not Campylobacter could be detected using conventional qPCR thresholds. A single porAf2 variant was predominant amongst flocks that would be determined to be Campylobacter  positive by conventional means, but a diverse pattern was seen amongst flocks that were Campylobacter  negative. The ability to routinely detect low levels of Campylobacter amongst broiler flocks at a much earlier age than would conventionally be identified requires a re-examination of how and when biosecurity measures are best applied for live birds. In addition, it may be useful to investigate why single Campylobacter variants proliferate in some broiler flocks and not others.


title: miR-34a negatively regulates cell cycle factor Cdt2/DTL in HPV infected Cervical Cancer Cells

abstract:
MicroRNAs have emerged as an important factor in regulating cell cycle and various other cellular processes. Aberration in microRNAs has been linked with development of several cancers and other diseases but still very little is known about the mechanism behind their function in regulating cellular processes. 99% of cervical cancer is caused by the infection of high-risk HPVs (HR HPVs) which suppresses multiple tumor suppressors and checkpoint factors of the host cell. It also stabilizes oncogenic proteins, one of them is Cdt2/DTL which promotes cell transformation and proliferation. In this study, we have reported that in cervical cancer cell lines miR-34a by targeting HPV E6 protein, regulates Cdt2/DTL protein level and leads to its destabilization. Destabilization of Cdt2 stabilizes onco-suppressor proteins like p21 and Set8 in these cell lines. We have also shown that the overexpression of miR-34a suppresses cell proliferation, invasion and migration capabilities of HPV positive cervical cancer cells which was reverted by overexpression of either HPV E6 or Cdt2 genes. This is the first-ever report to show that miR-34a regulates cell cycle factor Cdt2 by suppressing viral E6 protein level, which opens up the scope of exploring miR-34a as a specific therapy for cervical cancer treatment.

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title: Deep selection shapes the intragenomic diversity of rRNA genes

abstract: Ribosome biogenesis in eukaryotes is supported by hundreds of ribosomal RNA (rRNA) gene copies that are encoded in the ribosomal DNA (rDNA) and are thought to undergo frequent sequence homogenization by concerted evolution. Here, we present species-wide rDNA sequence analysis in Saccharomyces cerevisiae that challenges this model of evolution. We show that rDNA copies in yeast are far from homogeneous, both among and within isolates, and that rapid sequence homogenization is unlikely because many variants avoided fixation or elimination over evolutionary time. Instead, the diversity landscape across the rDNA shows clear functional stratification, suggesting that different copy-number thresholds for selection shape rDNA diversity. Notably, variants in the most highly conserved rDNA elements are sufficiently deleterious to exhibit signatures of purifying selection even when present in only 1% of rRNA gene copies. Our results portray a complex selection landscape that shapes rDNA diversity within a single species and reveal unexpectedly deep purifying selection of multi-copy genes.


title: Mitigating the Bfl-1-mediated antiapoptotic pathway in diffuse large B cell lymphoma by inhibiting HDACs

abstract:
Endogenous Bfl-1 expression renders diffuse large B-cell lymphoma (DLBCL) cells insensitive to Bcl-2 and/or Mcl-1 inhibitors. Considering the difficulties of developing a direct Bfl-1 inhibitor, we intended to inhibit histone deacetylase (HDAC) to mitigate the adverse biologic role of Bfl-1 by modulating Wt-1 and Noxa. In vitro assays including western blotting, qRT-PCR, proliferation assay, and flow cytometry were performed using DLBCL cell lines. shRNA-mediated Bfl-1 knockdown DLBCL cells were generated to verify the role of Bfl-1 in HDAC inhibitors sensitivity. DLBCL cells expressing high Bfl-1 exhibited enhanced sensitivity to pan-HDAC inhibitor panobinostat compared to low Bfl-1 expressing cells, mainly attributable to the difference in the amount of apoptosis. HDAC inhibitors decreased Bfl-1 and Wt-1 expressions while increased Noxa level in DLBCL, as we hypothesized. The Bfl-1 knockdown experiment demonstrated that HDAC inhibitors sensitivity depends on the expression level of Bfl-1 in DLBCL cells. Furthermore, we found the specific HDAC class was expected to play a critical role in Bfl-1 inhibition by comparing the results of several HDAC inhibitors. In summary, our study provides a rationale for using HDAC inhibitors to induce apoptosis in DLBCL patients using Bfl-1 as a predictive biomarker.

Key pointsO_LIDiffuse large B cell lymphoma shows apoptosis to HDAC inhibitors depending on the Bfl-1 expression level.
C_LIO_LIEffect of HDAC inhibitors in diffuse large B-cell lymphoma with high Bfl-1 is mediated via Noxa and Wt-1 with HDAC class-specificity.
C_LI


title: Molecular basis of uracil/H+ symport mechanism operated by the FurE/NCS1 transporter

abstract: Transporters mediate the uptake or efflux of solutes, metabolites and drugs across the cell membrane. The FurE symporter of uracil-allantoin-uric acid/H+ of Aspergillus nidulans has been used as a model eukaryotic transporter to address structure-function relationships and the mechanism of transport in the NCS1/APC family of transporters. Extensive genetic, functional and cellular studies, as well as homology modeling based on a prokaryotic transporter with a similar fold (Mhp1) have provided important information on specific structural elements of FurE. However, the exact mechanism by which substrates and proton or other cations are translocated by FurE or transporters with a similar fold remains elusive. In this study, we reveal the binding mode, translocation and release pathway of uracil/H+ from the extracellular space to the cytoplasm, using novel metadynamics calculations and rationally designed mutational analysis. In particular, Metadynamics Free Energy Surface maps provide the relative order of internalization of uracil and proton, permitting also selection of intermediate conformational states related to transport cycle. Funnel Metadynamics allow the sampling of specific interactions of both uracil and proton with residues during their internalization, generating a holistic model of the transport events in conjunction with experimental mutation studies. Our work not only complements and extends the existing knowledge on FurE same-fold transporters, but also challenges the so-called rocking bundle mechanism associated with biomedically interesting members of the APC superfamily of transporters.


title: Monitoring of urban ecological environment including air quality using satellite imagery

abstract: Rapid urbanisation has highlighted problems in the urban ecological environment and stimulated research on the evaluation of urban environments. In previous studies, key factors such as greenness, wetness, and temperature were extracted from satellite images to assess the urban ecological environment. Although air pollution has become increasingly serious as urbanisation proceeds, information on air pollution is not included in existing models. The Sentinel-5P satellite launched by the European Space Agency in 2017 is a reliable data source for monitoring air quality. By making full use of images from Landsat 8, Sentinel-2A, and Sentinel-5P, this work attempts to construct a new remote sensing monitoring index for urban ecology by adding air quality information to the existing remote sensing ecological index. The proposed index was tested in the Beijing metropolitan area using satellite data from 2020. The results obtained using the proposed index differ greatly in the central urban region and near large bodies of water from those obtained using the existing remote sensing monitoring model, indicating that air quality plays a significant role in evaluating the urban ecological environment. Because the model constructed in this study integrates information on vegetation, soil, humidity, heat, and air quality, it can comprehensively and objectively reflect the quality of the urban ecological environment. Consequently, the proposed remote sensing index provides a new approach to effectively monitoring the urban ecological environment.


title: Systemic ablation of Camkk2 impairs metastatic colonization and improves insulin sensitivity in TRAMP mice: Evidence for cancer cell-extrinsic CAMKK2 functions in prostate cancer

abstract: Despite early studies linking calcium-calmodulin protein kinase kinase 2 (CAMKK2) to prostate cancer cell migration and invasion, the role of CAMKK2 in metastasis in vivo remains unclear. Moreover, while CAMKK2 is known to regulate systemic metabolism, whether CAMKK2s effects on whole body metabolism would impact prostate cancer progression and/or related comorbidities is not known. Here, we demonstrate that germline ablation of Camkk2 slows, but does not stop, primary prostate tumorigenesis in the TRansgenic Adenocarcinoma Mouse Prostate (TRAMP) genetic mouse model. Consistent with prior epidemiological reports supporting a link between obesity and prostate cancer aggressiveness, TRAMP mice fed a high-fat diet exhibited a pronounced increase in the colonization of lung metastases. We demonstrated that this effect on metastatic spread was dependent on CAMKK2. Notably, diet-induced lung metastases exhibited a highly aggressive neuroendocrine phenotype. Concurrently, Camkk2 deletion improved insulin sensitivity in the same mice. Histological analyses revealed that cancer cells were smaller in the TRAMP;Camkk2-/- mice compared to TRAMP;Camkk2+/+ controls. Given the differences in circulating insulin levels, a known regulator of cell growth, we hypothesized that systemic CAMKK2 could promote prostate cancer cell growth and disease progression in part through cancer cell-extrinsic mechanisms. Accordingly, host deletion of Camkk2 impaired the growth of syngeneic murine prostate tumors in vivo, confirming nonautonomous roles for CAMKK2 in prostate cancer. Cancer cell size and mTOR signaling was diminished in tumors propagated in Camkk2-null mice. Together, these data indicate that, in addition to cancer cell-intrinsic roles, CAMKK2 promotes prostate cancer progression via tumor-extrinsic mechanisms. Further, we propose that CAMKK2 inhibition may also help combat common metabolic comorbidities in men with advanced prostate cancer.


title: Safety assessment of insecticidal proteins: A case study utilizing His-tagged protein to determine the safety of Mpp75Aa1.1, a new ETX_MTX2 protein that controls western corn rootworm

abstract: The recently discovered insecticidal protein Mpp75Aa1.1 from Brevibacillus laterosporus is one member of the ETX_MTX family of beta-pore forming proteins ({beta}-PFPs) expressed in genetically modified (GM) maize to control western corn rootworm (WCR; Diabrotica virgifera virgifera LeConte). In this paper, bioinformatic analysis establishes that although Mpp75Aa1.1 shares varying degrees of similarity to members of the ETX_MTX2 protein family, it is unlikely to contribute to any allergenic, toxic, or otherwise adverse biological effects. The safety of Mpp75Aa1.1 is further supported by a weight of evidence including evaluation of history of safe use (HOSU) of ETX_MTX2 proteins. Assessments using either purified Mpp75Aa1.1 protein or a poly-histidine-tagged (His-tagged) variant of the Mpp75Aa1.1 protein demonstrate that both forms of the protein are heat labile at temperatures at or above 55 {degrees}C, degraded by gastrointestinal proteases within 0.5 min, and have no adverse effects in acute mouse oral toxicity studies at a dose level of 1920 or 2120 mg/kg body weight. Results also indicate that the domain-based protein characterization should be considered as part of the weight of evidence for the safe consumption of food or feed. Furthermore, these results support the use of His-tagged proteins as suitable surrogates for assessing the safety of their non-tagged parent proteins.


title: Rhythmic modulation of prediction errors: a possible role for the beta-range in speech processing

abstract: Natural speech perception requires processing the current acoustic input while keeping in mind the preceding one and predicting the next. This complex computational problem could be handled by a multi timescale hierarchical inferential process that coordinates information flow up and down the language hierarchy. While theta and low-gamma neural frequency scales are convincingly involved in bottom-up syllable-tracking and phoneme-level speech encoding, the beta rhythm is more loosely associated with top-down processes without being assigned yet a specific computational function. Here we tested the hypothesis that the beta rhythm drives the precision of states during the speech recognition hierarchical inference process. We used a predictive coding model that recognizes syllables on-line in natural sentences, in which the precision of prediction errors is rhythmically modulated, resulting in alternating bottom-up vs. top-down processing regimes. We show that recognition performance increases with the rate of precision updates, with an optimal efficacy in the beta range (around 20 Hz). The model further performs when prediction errors pertaining respectively to syllable timing and syllable identity oscillate in antiphase. These results suggest that online syllable recognition globally benefits from the alternation of bottom-up and top-down dominant regime at beta rate, and that the gain is stronger when different features are also analyzed in alternation. These results speak to a discontinuous account of inferential operations in speech processing.


title: Serotonin Modulates an Inhibitory Input to the Central Amygdala from the Ventral Periaqueductal Gray

abstract: Fear is an adaptive state that drives defensive behavioral responses to specific and imminent threats. The central nucleus of the amygdala (CeA) is a critical site of adaptations that are required for the acquisition and expression of fear, in part due to alterations in the activity of inputs to the CeA. Here, we characterize a novel GABAergic input to the CeA from the ventral periaqueductal gray area (vPAG) using fiber photometry and ex vivo whole-cell slice electrophysiology combined with optogenetics and pharmacology. GABA transmission from this ascending vPAG-CeA input was enhanced by bath application of serotonin via activation of serotonin type 2C (5HT2C) receptors. Results indicate that these receptors are presynaptic. Interestingly, we found that GABA release from the vPAG-CeA input is enhanced following fear learning via activation of 5HT2C receptors and that this pathway is dynamically engaged during fear learning. Additionally, we characterized serotonin release in the CeA during fear learning and recall for the first time using fiber photometry coupled to a serotonin biosensor. Together, these findings describe a mechanism by which serotonin modulates GABA release from ascending vPAG GABA inputs to the CeA and characterize a role for this pathway in fear learning.


title: Cortical integration of higher-order thalamic inputs is lineage-dependent

abstract: Primary sensory cortex receives and integrates inputs from first-order and higher-order thalamic nuclei. First-order inputs convey sensory information from the periphery and exhibit simple response properties, whereas higher-order inputs exhibit more complex response properties, provide contextual feedback, and can modulate first-order inputs. Here we show that the way in which cortical neurons integrate these thalamic inputs, reflects the progenitor cell from which the cortical neurons derive. Within layer 4 of mouse primary somatosensory cortex, excitatory neurons that derive from apical intermediate progenitors exhibit multi-whisker response properties and receive higher-order thalamic input, in a manner consistent with their dendritic morphology. These properties depend upon the expression levels of the transcription factor Lhx2, which when increased, abolishes the higher-order properties of apical intermediate progenitor-derived neurons, and disrupts the induction of sensory-evoked plasticity. These data reveal a lineage-dependent mechanism that establishes the integration and functional contribution of higher-order thalamic inputs within cortex.


title: Mapping the subcortical connectome using in vivo diffusion MRI: feasability and reliability

abstract: Tractography combined with regions of interest (ROIs) has been used to non-invasively study the structural connectivity of the cortex as well as to assess the reliability of these connections. However, the subcortical connectome (subcortex to subcortex) has not been comprehensively examined, in part due to the difficulty of performing tractography in this complex and compact region. In this study, we performed an in vivo investigation using tractography to assess the feasibility and reliability of mapping known connections between structures of the subcortex using the test-retest dataset from the Human Connectome Project (HCP). We further validated our observations using a separate unrelated subjects dataset from the HCP. Quantitative assessment was performed by computing tract densities and spatial overlap of identified connections between subcortical ROIs. Further, known connections between structures of the basal ganglia and thalamus were identified and visually inspected, comparing tractography reconstructed trajectories with descriptions from tract-tracing studies. Our observations demonstrate both the feasibility and reliability of using a data-driven tractography-based approach to map the subcortical connectome in vivo.


title: Mapping the subcortical connectome using in vivo diffusion MRI: feasibility and reliability


title: Action sequence dynamics rely on accessory hyperdirect pathway-related targets in the striatum

abstract: Performing several actions in swift succession is often necessary to exploit known contingencies in the environment. However, after a change in the contingency rules, the ability to appropriately adapt rapid action sequences must be procured for continued success. By combining analyses of behavioural microstructure with circuit-specific tracing in mice, we report on a relationship between action timing-variability and successful adaptation that relies on post-synaptic targets of primary motor cortical (M1) projections to dorsolateral striatum (DLS). We found that M1 hyperdirect pathway projections to the STN also send dense axonal collaterals to external globus pallidus and dorsal striatum, with the highest synaptic volumes found in the DLS. Specific interruption of the M1[->]DLS circuit reduced the proportion of successful sequences while speeding-up and reducing action timing-variability, revealing a role for M1[->]DLS circuitry in setting the exploration/exploitation balance that is required for adaptively guiding the timing and success of instrumental action.


title: A multiplexed in vivo approach to identify driver genes in small cell lung cancer

abstract: Small cell lung cancer (SCLC) is a highly lethal form of lung cancer. The high mutation burden in SCLC cells makes it challenging to predict key drivers of SCLC from genome sequencing data, thereby hindering the identification of possible therapeutic targets. Here we develop a quantitative multiplexed approach based on lentiviral barcoding with somatic CRISPR/Cas9-mediated genome editing to functionally investigate candidate regulators of tumor initiation and growth in genetically engineered mouse models of SCLC. Lentiviral vector-mediated SCLC initiation was greatly enhanced by naphthalene pre-treatment, enabling high multiplicity of tumor clones for analysis through high-throughput sequencing methods. Based on a meta-analysis across multiple human SCLC genomic datasets, we quantified the impact of inactivating 39 genes across many candidate pathways and captured both positive and detrimental effects on SCLC initiation and progression upon gene inactivation. This analysis and subsequent validation in human SCLC cells identified TSC1 in the PI3K-AKT-mTOR pathway as a robust tumor suppressor in SCLC. This new approach should illuminate novel drivers of SCLC, facilitate the development of precision therapies for defined SCLC genotypes, and identify new therapeutic targets.


title: Improving the Safety of Cultured Meat Using Basal Medium Prepared using Food Ingredients

abstract: Currently, meat production involves environmental issues and high costs; one solution to address this may be to produce meat via cell culture. Therefore, there is an urgent demand for the development of cell culture methods that replace raw materials with food materials to produce cultured meat as food. In this study, we designed food-grade-Dulbeccos Modified Eagles Medium (FG-DMEM); when the cells cultured in FG-DMEM and regular DMEM were compared, there was no significant difference in cell growth or differentiation. Therefore, FG-DMEM can be used for research and safe production of cultured meat.

category: cell biology


title: ALS-associated mutant KIF5A forms oligomers and aggregates and induces neuronal toxicity

abstract: KIF5A is a kinesin superfamily motor protein that transports various cargos in neurons. Mutations in Kif5a cause familial amyotrophic lateral sclerosis (ALS). These ALS mutations are in the intron of Kif5a and induce mis-splicing of KIF5A mRNA, leading to splicing out of exon 27, which in human KIF5A encodes the cargo-binding tail domain of KIF5A. Therefore, it has been suggested that ALS is caused by loss of function of KIF5A. However, the precise mechanisms regarding how mutations in KIF5A cause ALS remain unclear. Here, we show that an ALS-associated mutant of KIF5A, KIF5A({Delta}exon27), is predisposed to form oligomers and aggregates in cultured mouse cell lines. Interestingly, purified KIF5A({Delta}exon27) oligomers showed more active movement on microtubules than wild type KIF5A in vitro. Purified KIF5A({Delta}exon27) was prone to form aggregates in vitro. Moreover, KIF5A({Delta}exon27)-expressing Caenorhabditis elegans neurons showed morphological defects. These data collectively suggest that ALS-associated mutations of KIF5A are toxic gain-of-function mutations rather than simple loss-of-function mutations.


title: An ALS-associated mutant KIF5A forms oligomers and aggregates and induces neuronal toxicity


title: The force required to remove tubulin from the microtubule lattice

abstract: Severing enzymes and molecular motors extract tubulin from the walls of microtubules by exerting mechanical force on subunits buried in the lattice. However, how much force is needed to remove tubulin from microtubules is unknown, as is the pathway by which subunits are removed. Using a site-specific functionalization method, we applied forces to the C-terminus of -tubulin with an optical tweezer and found that a force of [~]30 pN is required to extract tubulin from the microtubule wall. Consistent with this force, we show that several kinesins can also extract tubulin. Additionally, we discovered that partial unfolding is an intermediate step in tubulin removal. The unfolding and extraction forces are similar to those generated by AAA-unfoldases, suggesting that severing proteins such as spastin and katanin use an unfoldase mechanism. Our results reveal the response of tubulin to mechanical force and advance our understanding of severing enzymes and microtubule stability.


title: Autophagy-cell death balance is maintained by Polycomb-mediated regulation during stem cell differentiation

abstract: Autophagy is a conserved cytoprotective process, aberrations in which, lead to numerous degenerative disorders. While the cytoplasmic components of autophagy have been extensively studied, the epigenetic regulation of autophagy genes, especially in stem cells, is less understood. Deciphering the epigenetic regulation of autophagy genes becomes increasingly relevant given the therapeutic benefits of small-molecule epigenetic inhibitors in novel treatment modalities. We observe that, during retinoic acid-mediated differentiation of mouse embryonic stem cells (mESCs), autophagy is induced, and identify the Polycomb enzyme EZH2 as a regulator of this process. In mESCs, EZH2 represses several autophagy genes including the autophagy regulator Dram1. EZH2 facilitates the formation of a bivalent chromatin domain at the Dram1 promoter, which allows the expression of the gene and induction of autophagy during differentiation, while still retaining the repressive H3K27me3 mark. EZH2 inhibition leads to loss of the bivalent domain, and a consequential "hyper- expression" of Dram1, with extensive cell death. This study shows that Polycomb group proteins help maintain an autophagy-cell death balance during stem cell differentiation, in part, by regulating the expression of the Dram1 gene.


title: Identification of a novel chalcone reductase gene for isoliquiritigenin biosynthesis in dahlia (Dahlia variabilis)

abstract: Butein is one of flavonoids conferring bright yellow flower color and is a precursor of aurone in some species. Butein is synthesized by two steps, 3-malonyl CoA and 4-coumaloyl CoA are converted to isoliquiritigenin in the first step, and then isoliquiritigenin is converted to butein in the second step. In the first step, chalcone synthase (CHS) and chalcone reductase (CHR) catalyze this reaction, however, CHR has been reported for the isoflavone biosynthesis pathway in legumes, and CHR for butein biosynthesis has not yet been isolated. In this study, we report CHR that is evolutionally different gene from legume species is involved in isoliquiritigenin biosynthesis in dahlia. To isolate CHR gene, we conducted comparative RNA-seq analysis between  Shukuhai and its butein-loss lateral mutant  Rinka. We found DvCHR showed significant difference in expression levels that encodes an aldo-keto reductase (AKR) 13 family protein, which was phylogenetically different from legume CHRs belonging to AKR4A family. Gene expression levels and genotype of DvCHR were correlated with butein accumulation among various dahlia cultivars. Though single over expression of DvCHR was not able to accumulate isoliquiritigenin in tobacco, co-overexpression of DvCHR with a chalcone glucosyltransferase Am4'CGT and a MYB transcription factor CaMYBA successfully induced isoliquiritigenin accumulation. In addition, DvCHR homologous gene expression was detected from butein or aurone accumulating Coreopsideae species but not from non-butein or non-aurone accumulating Asteraceae species. These results indicated DvCHR functions as chalcone reductase for butein biosynthesis in dahlia, and isoliquiritigenin biosynthesis in Coreopsideae species has been developed independently from legume species.


title: Stability and learning in excitatory synapses by nonlinear inhibitory plasticity

abstract: Synaptic changes underlie learning and memory formation in the brain. But synaptic plasticity of excitatory synapses on its own is unstable, leading to unlimited growth of synaptic strengths without additional homeostatic mechanisms. To control excitatory synaptic strengths we propose a novel form of synaptic plasticity at inhibitory synapses. We identify two key features of inhibitory plasticity, dominance of inhibition over excitation and a nonlinear dependence on the firing rate of postsynaptic excitatory neurons whereby inhibitory synaptic strengths change in the same direction as excitatory synaptic strengths. We demonstrate that the stable synaptic strengths realized by this novel inhibitory plasticity achieve a fixed excitatory/inhibitory set-point in agreement with experimental results. Applying a disinhibitory signal can gate plasticity and lead to the generation of receptive fields and strong bidirectional connectivity in a recurrent network. Hence, a novel form of nonlinear inhibitory plasticity can simultaneously stabilize excitatory synaptic strengths and enable learning upon disinhibition.


title: LTD-inducing low frequency stimulation enhances p-Tau181 and p-Tau217 in an age-dependent manner in live rats

abstract: The progressive cognitive decline in Alzheimers disease (AD) patients correlates with the extent of tau pathology, in particular tau hyperphosphorylation, which is strongly age-associated. Although elevation of phosphorylated tau (p-Tau) on residues Thr181 (p-Tau181), Thr217 (p-Tau217), and Thr231 (p-Tau231) in cerebrospinal fluid or blood are recently proposed to be particularly sensitive markers of early AD, the generation of p-Tau during brain activity is poorly understood. A major form of synaptic plasticity, long-term depression (LTD), has recently been linked to the enhancement of tau phosphorylation. Here we show that low frequency stimulation (LFS), used to induce LTD, enhances p-Tau181 and p-Tau217 in an age-dependent manner in the hippocampus of live rats. In contrast, phosphorylation at residues Thr231, Ser202/Thr205, and Ser396 is less sensitive to LFS. Pharmacological antagonism of either NMDA or metabotropic glutamate 5 (mGluR5) receptors inhibits the elevation of both p-Tau181 and p-Tau217. Targeting ageing with a small molecule cognitive enhancer ISRIB (trans-isomer) prevents the enhancement of p-Tau by LFS in aged rats. Together, our data provide an in vivo means to uncover brain plasticity-related cellular and molecular processes of tau phosphorylation in health and ageing conditions.