text:
FOR YOUNG SCIENTISTS
FOR INDUSTRY AND HOSPITALS
FOR PUBLIC AND PRESS
Pau Gorostiza Langa
Group Leader / ICREA Research Professor
Nanoprobes and Nanoswitches
pgorostiza@ibecbarcelona.eu
Pau Gorostiza graduated in physics at the University of Barcelona (UB), where he also obtained his PhD (European Doctorate) in the field of semiconductor electrochemistry. He also worked at the microscopy facility of the UB, where he gained experience in force microscopy and spectroscopy of biological samples, as well as in nanotechnology applied to materials science. He has visited the CNRS and the University Pierre and Marie Curie in Paris (France), and the University of California at Berkeley (USA), where he switched his research interests toward ion channel electrophysiology and chemical biology, specifically on photopharmacological manipulation of proteins for remotely controlling biological activity. He is currently ICREA Research Professor at the Institute for Bioengineering of Catalonia (IBEC), where he develops light regulated ligands of neuronal proteins, and studies electron transfer in redox proteins and photosynthetic complexes using EC-STM/AFM. He has published more than 100 articles (3200 citations, h-index 29) and holds 7 patents (5 licensed), and has supervised 8 postdoctoral fellows and 9 PhDs. In addition, he has given several invited lectures (including Heraeus Seminar on Electrochemical Surface Science, Lorenz Workshop on Optogenetics and Bunsen Discussion meeting / Gerischer-Kolb Symposium on Bioelectrochemistry) and organized 4 international workshops. He has participated in more than 40 competitive research grants, and he is principal investigator of 5 Spanish grants, 7 European grants and 4 private foundation grants (including a Career Development Award of the Human Frontier Science Program (HFSP) and European Research Council (ERC) Starting and Proof of Concept Grants).
Staff member publications
Prischich, Davia, Gomila, Alexandre M. J., Milla-Navarro, Santiago, Sangüesa, Gemma, Diez-Alarcia, Rebeca, Preda, Beatrice, Matera, Carlo, Batlle, Montserrat, Ramírez, Laura, Giralt, Ernest, Hernando, Jordi, Guasch, Eduard, Meana, J. Javier, de la Villa, Pedro, Gorostiza, Pau, (2020). Adrenergic modulation with photochromic ligands Angewandte Chemie International Edition Online ahead of print
Adrenoceptors are ubiquitous and mediate important autonomic functions as well as modulating arousal, cognition and pain on a central level. Understanding these physiological processes and their underlying neural circuits requires manipulating adrenergic neurotransmission with high spatio-temporal precision. Here we present a first generation of photochromic ligands (adrenoswitches) obtained via azologization of a class of cyclic amidines related to the known ligand clonidine. Their pharmacology, photochromism, bioavailability and lack of toxicity allow for broad biological applications, as demonstrated by controlling locomotion in zebrafish and pupillary responses in mice.
Keywords: Adrenergic, Neurotransmitters, Azo compounds, Biological activity, Photochromism.
Polenghi, Alice, Nieus, Thierry, Guazzi, Stefania, Gorostiza, Pau, Petrini, Enrica Maria, Barberis, Andrea, (2020). Kainate receptor activation shapes short-term synaptic plasticity by controlling receptor lateral Mobility at glutamatergic synapses Cell Reports 31, (10), 107735
Kainate receptors (KARs) mediate postsynaptic currents with a key impact on neuronal excitability. However, the molecular determinants controlling KAR postsynaptic localization and stabilization are poorly understood. Here, we exploit optogenetic and single-particle tracking approaches to study the role of KAR conformational states induced by glutamate binding on KAR lateral mobility at synapses. We report that following glutamate binding, KARs are readily and reversibly trapped at glutamatergic synapses through increased interaction with the β-catenin/N-cadherin complex. We demonstrate that such activation-dependent synaptic immobilization of KARs is crucial for the modulation of short-term plasticity of glutamatergic synapses. Thus, the present study unveils the crosstalk between conformational states and lateral mobility of KARs, a mechanism regulating glutamatergic signaling, particularly in conditions of sustained synaptic activity.
Rustler, Karin, Gomila, Alexandre, Maleeva, Galyna, Gorostiza, Pau, Bregestovski, Piotr, König, Burkhard, (2020). Optical Control of GABAA Receptors with a Fulgimide-Based Potentiator Chemistry - A European Journal Accepted Articles,
Optogenetic and photopharmacological tools to manipulate neuronal inhibition have limited efficacy and reversibility. We report the design, synthesis, and biological evaluation of Fulgazepam, a fulgimide derivative of benzodiazepine that behaves as a pure potentiator of ionotropic γ-aminobutyric acid receptors (GABA A Rs) and displays full and reversible photoswitching in vitro and in vivo. The compound enables high-resolution studies of GABAergic neurotransmission, and phototherapies based on localized, acute, and reversible neuroinhibition.
Gomila, Alexandre M. J., Rustler, Karin, Maleeva, Galyna, Nin-Hill, Alba, Wutz, Daniel, Bautista-Barrufet, Antoni, Rovira, Xavier, Bosch, Miquel, Mukhametova, Elvira, Petukhova, Elena, Ponomareva, Daria, Mukhamedyarov, Marat, Peiretti, Franck, Alfonso-Prieto, Mercedes, Rovira, Carme, König, Burkhard, Bregestovski, Piotr, Gorostiza, Pau, (2020). Photocontrol of endogenous glycine receptors in vivo Cell Chemical Biology In press
Glycine receptors (GlyRs) are indispensable for maintaining excitatory/inhibitory balance in neuronal circuits that control reflexes and rhythmic motor behaviors. Here we have developed Glyght, a GlyR ligand controlled with light. It is selective over other Cys-loop receptors, is active in vivo, and displays an allosteric mechanism of action. The photomanipulation of glycinergic neurotransmission opens new avenues to understanding inhibitory circuits in intact animals and to developing drug-based phototherapies.
Keywords: Glycine receptors, Photopharmacology, Optopharmacology, Inhibitory neurotransmission, CNS, Photoswitch
Maleeva, Galyna, Nin-Hill, Alba, Rustler, Karin, Petukhova, Elena, Ponomareva, Daria, Mukhametova, Elvira, Gomila-Juaneda, Alexandre, Wutz, Daniel, Alfonso-Prieto, Mercedes, König, Burkhard, Gorostiza, Pau, Bregestovski, Piotr, (2020). Subunit-specific photocontrol of glycine receptors by azobenzene-nitrazepam photoswitcher eneuro ahead,
Photopharmacology is a unique approach that through a combination of photochemistry methods and advanced life science techniques allows the study and control of specific biological processes, ranging from intracellular pathways to brain circuits. Recently, a first photochromic channel blocker of anion-selective GABAA receptors, Azo-NZ1, has been described. In the present study using patch-clamp technique in heterologous system and in mice brain slices, site-directed mutagenesis and molecular modelling we provide evidence of the interaction of Azo-NZ1 with glycine receptors (GlyRs) and determine the molecular basis of this interaction. Glycinergic synaptic neurotransmission determines an important inhibitory drive in the vertebrate nervous system and plays a crucial role in the control of neuronal circuits in the spinal cord and brain stem. GlyRs are involved in locomotion, pain sensation, breathing and auditory function, as well as in the development of such disorders as hyperekplexia, epilepsy and autism. Here we demonstrate that Azo-NZ1 blocks in a UV dependent manner the activity of alpha2 GlyRs (GlyR2), while being barely active on alpha1 GlyRs (GlyR1). The site of Azo-NZ1 action is in the chloride-selective pore of GlyR at the 2' position of transmembrane helix 2 and amino acids forming this site determine the difference in Azo-NZ1 blocking activity between GlyR2 and GlyR1. This subunit specific modulation is also shown on motoneurons of brainstem slices from neonatal mice that switch during development from expressing "foetal" GlyR2 to "adult" GlyR1 receptors. Significance Statement Photochromic molecules are becoming widely used for studying and modulating various biological processes. Successful application of these compounds, whose activity can be controlled with light, potentially provides a promising tool for future therapeutic approaches. The main advantage of such compounds is their precise spatial and temporal selectivity, a property that favours specific drug action and diminishes their side effects. In the present study, we describe in detail the interaction of the novel azobenzene-nitrazepam-based photochromic compound (Azo-NZ1) with glycine receptors (GlyRs) and determine its subunit-specific blocking activity in the Cl-selective pore of GlyRs. This compound offers a new strategy for specific control of glycinergic circuits and stepping stone for design of new GlyR-active drugs.
Keywords: Brain slices, Glycine receptors, Hypoglossal motoneurons, Molecular modelling, Patch-clamp, Photopharmacology
Riefolo, F., Matera, C., Garrido-Charles, A., Gomila, A., Sortino, R., Agnetta, L., Claro, E., Masgrau, R., Holzgrabe, U., Batlle, M., Decker, M., Guasch, E., Gorostiza, P., (2019). Optical control of cardiac function with a photoswitchable muscarinic agonist Journal of the American Chemical Society 141, (18), 7628-7636
Light-triggered reversible modulation of physiological functions offers the promise of enabling on-demand spatiotemporally controlled therapeutic interventions. Optogenetics has been successfully implemented in the heart, but significant barriers to its use in the clinic remain, such as the need for genetic transfection. Herein, we present a method to modulate cardiac function with light through a photoswitchable compound and without genetic manipulation. The molecule, named PAI, was designed by introduction of a photoswitch into the molecular structure of an M2 mAChR agonist. In vitro assays revealed that PAI enables light-dependent activation of M2 mAChRs. To validate the method, we show that PAI photoisomers display different cardiac effects in a mammalian animal model, and demonstrate reversible, real-time photocontrol of cardiac function in translucent wildtype tadpoles. PAI can also effectively activate M2 receptors using two-photon excitation with near-infrared light, which overcomes the scattering and low penetration of short-wave-length illumination, and offers new opportunities for intravital imaging and control of cardiac function.
Lopez-Martinez, Montserrat, López-Ortiz, Manuel, Antinori, Maria Elena, Wientjes, Emilie, Nin-Hill, Alba, Rovira, Carme, Croce, Roberta, Díez-Pérez, Ismael, Gorostiza, Pau, (2019). Electrochemically gated long distance charge transport in photosystem I Angewandte Chemie International Edition 58, (38), 13280-13284
The transport of electrons along photosynthetic and respiratory chains involves a series of enzymatic reactions that are coupled through redox mediators, including proteins and small molecules. The use of native and synthetic redox probes is key to understand charge transport mechanisms, and to design bioelectronic sensors and solar energy conversion devices. However, redox probes have limited tunability to exchange charge at the desired electrochemical potentials (energy levels) and at different protein sites. Here, we take advantage of electrochemical scanning tunneling microscopy (ECSTM) to control the Fermi level and nanometric position of the ECSTM probe in order to study electron transport in individual photosystem I (PSI) complexes. Current-distance measurements at different potentiostatic conditions indicate that PSI supports long-distance transport that is electrochemically gated near the redox potential of P700, with current extending farther under hole injection conditions.
Keywords: Current decay, ECSTM, Electrochemical gate, Electron transfer, Photosynthesis
Cabré, Gisela, Garrido-Charles, Aida, Moreno, Miquel, Bosch, Miquel, Porta-de-la-Riva, Montserrat, Krieg, Michael, Gascón-Moya, Marta, Camarero, Núria, Gelabert, Ricard, Lluch, José M., Busqué, F., Hernando, Jordi, Gorostiza, Pau, Alibés, Ramon, (2019). Rationally designed azobenzene photoswitches for efficient two-photon neuronal excitation Nature Communications 10, (1), 907
Manipulation of neuronal activity using two-photon excitation of azobenzene photoswitches with near-infrared light has been recently demonstrated, but their practical use in neuronal tissue to photostimulate individual neurons with three-dimensional precision has been hampered by firstly, the low efficacy and reliability of NIR-induced azobenzene photoisomerization compared to one-photon excitation, and secondly, the short cis state lifetime of the two-photon responsive azo switches. Here we report the rational design based on theoretical calculations and the synthesis of azobenzene photoswitches endowed with both high two-photon absorption cross section and slow thermal back-isomerization. These compounds provide optimized and sustained two-photon neuronal stimulation both in light-scattering brain tissue and in Caenorhabditis elegans nematodes, displaying photoresponse intensities that are comparable to those achieved under one-photon excitation. This finding opens the way to use both genetically targeted and pharmacologically selective azobenzene photoswitches to dissect intact neuronal circuits in three dimensions.
Pittolo, Silvia, Lee, Hyojung, Lladó, Anna, Tosi, Sébastien, Bosch, Miquel, Bardia, Lídia, Gómez-Santacana, Xavier, Llebaria, Amadeu, Soriano, Eduardo, Colombelli, Julien, Poskanzer, Kira E., Perea, Gertrudis, Gorostiza, Pau, (2019). Reversible silencing of endogenous receptors in intact brain tissue using two-photon pharmacology Proceedings of the National Academy of Sciences of the United States of America 116, (27), 13680-13689
The physiological activity of proteins is often studied with loss-of-function genetic approaches, but the corresponding phenotypes develop slowly and can be confounding. Photopharmacology allows direct, fast, and reversible control of endogenous protein activity, with spatiotemporal resolution set by the illumination method. Here, we combine a photoswitchable allosteric modulator (alloswitch) and 2-photon excitation using pulsed near-infrared lasers to reversibly silence metabotropic glutamate 5 (mGlu5) receptor activity in intact brain tissue. Endogenous receptors can be photoactivated in neurons and astrocytes with pharmacological selectivity and with an axial resolution between 5 and 10 µm. Thus, 2-photon pharmacology using alloswitch allows investigating mGlu5-dependent processes in wild-type animals, including synaptic formation and plasticity, and signaling pathways from intracellular organelles.
Keywords: Photopharmacology, Photoactivation, Pharmacological selectivity, Functional silencing, 2-photon pharmacology
Maleeva, Galyna, Wutz, Daniel, Rustler, Karin, Nin-Hill, Alba, Rovira, Carme, Petukhova, Elena, Bautista-Barrufet, Antoni, Gomila-Juaneda, Alexandre, Scholze, Petra, Peiretti, Franck, Alfonso-Prieto, Mercedes, König, Burkhard, Gorostiza, Pau, Bregestovski, Piotr, (2019). A photoswitchable GABA receptor channel blocker British Journal of Pharmacology 176, (15), 2661-2677
BACKGROUND AND PURPOSE: Anion-selective Cys-loop receptors (GABA and glycine receptors) provide the main inhibitory drive in the CNS. Both types of receptor operate via chloride-selective ion channels, though with different kinetics, pharmacological profiles, and localization. Disequilibrium in their function leads to a variety of disorders, which are often treated with allosteric modulators. The few available GABA and glycine receptor channel blockers effectively suppress inhibitory currents in neurons, but their systemic administration is highly toxic. With the aim of developing an efficient light-controllable modulator of GABA receptors, we constructed azobenzene-nitrazepam (Azo-NZ1), which is composed of a nitrazepam moiety merged to an azobenzene photoisomerizable group. EXPERIMENTAL APPROACH: The experiments were carried out on cultured cells expressing Cys-loop receptors of known subunit composition and in brain slices using patch-clamp. Site-directed mutagenesis and molecular modelling approaches were applied to evaluate the mechanism of action of Azo-NZ1. KEY RESULTS: At visible light, being in trans‐configuration, Azo-NZ1 blocked heteromeric α1/β2/γ2 GABAA receptors, ρ2 GABAA (GABAC), and α2 glycine receptors, whereas switching the compound into cis-state by UV illumination restored the activity. Azo-NZ1 successfully photomodulated GABAergic currents recorded from dentate gyrus neurons. We demonstrated that in trans-configuration, Azo-NZ1 blocks the Cl-selective ion pore of GABA receptors interacting mainly with the 2′ level of the TM2 region. CONCLUSIONS AND IMPLICATIONS: Azo-NZ1 is a soluble light-driven Cl-channel blocker, which allows photo-modulation of the activity induced by anion-selective Cys-loop receptors. Azo-NZ1 is able to control GABAergic postsynaptic currents and provides new opportunities to study inhibitory neurotransmission using patterned illumination.
Cabré, Gisela, Garrido-Charles, Aida, González-Lafont, Àngels, Moormann, Widukind, Langbehn, Daniel, Egea, David, Lluch, José M., Herges, Rainer, Alibés, Ramon, Busqué, Félix, Gorostiza, Pau, Hernando, Jordi, (2019). Synthetic photoswitchable neurotransmitters based on bridged azobenzenes Organic Letters 21, (10), 3780-3784
Photoswitchable neurotransmitters of ionotropic kainate receptors were synthesized by tethering a glutamate moiety to disubstituted C2-bridged azobenzenes, which were prepared through a novel methodology that allows access to diazocines with higher yields and versatility. Because of the singular properties of these photochromes, photoisomerizable compounds were obtained with larger thermal stability for their inert cis isomer than for their biologically activity trans state. This enabled selective neuronal firing upon irradiation without background activity in the dark.
Nevola, Laura, Varese, Monica, Martín-Quirós, Andrés, Mari, Giacomo, Eckelt, Kay, Gorostiza, Pau, Giralt, Ernest, (2019). Targeted nanoswitchable inhibitors of protein-protein interactions involved in apoptosis ChemMedChem 14, 100-106
Progress in drug delivery is hampered by the lack of efficient strategies to target drugs with high specificity and precise spatiotemporal regulation. The remote control of nanoparticles and drugs with light allows controlling their action site and dosage. Peptide-based drugs are very specific, non-immunogenic and can be designed to cross the plasma membrane. In order to combine target specificity and remote control of drug action, here we describe a versatile strategy based on a generalized template to design nanoswitchable peptides that modulate protein-protein interactions with light. This approach is demonstrated to photomodulate two important targets involved in apoptosis (the interactions Bcl-xL/Bak and MDM2/p53), but can be applied to a large pool of therapeutically relevant protein-protein interactions mediated by alpha helical motifs. The template can be adjusted using readily available information about the hot spots (residues contributing most to the binding energy) at the protein-protein interface of interest.
Matera, C., Gomila, A. M. J., Camarero, N., Libergoli, M., Soler, C., Gorostiza, P., (2019). Photochromic antifolate for light-activated chemotherapy Proceedings of SPIE 17th International Photodynamic Association World Congress , SPIE (Cambridge, USA) 11070, 110709H
Although cytotoxic chemotherapy is one of the primary pharmacological treatments for chronic hyperproliferative diseases such as cancer and psoriasis, its efficacy and tolerability are in many cases dramatically limited by off-target toxicity. A promising approach to improve these therapies is to activate the drugs exclusively at their desired place of action. In fact, in those diseases that would benefit from a highly localized treatment, a precise spatiotemporal control over the activity of a chemotherapeutic agent would allow reducing the concentration of active compound outside the targeted region, improving the tolerability of the treatment. Light is a powerful tool in this respect: it offers unparalleled opportunities as a non-invasive regulatory signal for pharmacological applications because it can be delivered with high precision regarding space, time, intensity and wavelength. Photopharmacology represents a new and emerging approach in this regard since the energy of light is used to change the structure of the drug and hence to switch its pharmacological activity on and off on demand. We describe here phototrexate, the first light-regulated inhibitor of the human DHFR. Enzyme and cell viability assays demonstrated that phototrexate behaves as a potent antifolate in its cis configuration, obtained under UVA illumination, and that it is nearly inactive in its dark-relaxed trans form. Experiments in zebrafish confirmed that phototrexate can disrupt folate metabolism in a light-dependent fashion also in vivo. Overall, phototrexate represents a potential candidate towards the development of an innovative photoactivated antifolate chemotherapy.
Keywords: Cancer, Dermatology, Methotrexate, Photoactivated chemotherapy, Photodynamic therapy, Phototherapy, Psoriasis, Rheumatoid arthritis
Matera, Carlo, Gomila-Juaneda, Alexandre, Camarero, Núria, Libergoli, Michela, Soler, Concepció, Gorostiza, Pau, (2018). A photoswitchable antimetabolite for targeted photoactivated chemotherapy Journal of the American Chemical Society 140, (46), 15764-15773
The efficacy and tolerability of systemically administered anticancer agents are limited by their off-target effects. Precise spatiotemporal control over their cytotoxic activity would allow improving chemotherapy treatments, and light-regulated drugs are well suited to this purpose. We have developed phototrexate, the first photoswitchable inhibitor of the human dihydrofolate reductase (DHFR), as a photochromic analog of methotrexate, a widely prescribed chemotherapeutic drug to treat cancer and psoriasis. Quantification of the light-regulated DHFR enzymatic activity, cell proliferation, and in vivo effects in zebrafish show that phototrexate behaves as a potent antifolate in its photoactivated cis configuration, and that it is nearly inactive in its dark-relaxed trans form. Thus, phototrexate constitutes a proof-of-concept to design light-regulated cytotoxic small molecules, and a step forward to develop targeted anticancer photochemotherapies with localized efficacy and reduced adverse effects.
Keywords: Photopharmacology, Photodynamic therapy, Antiproliferative, Arthritis, Psoriasis, Nanomedicine
Lagunas, A., Guerra-Castellano, A., Nin-Hill, A., Díaz-Moreno, I., De la Rosa, M. A., Samitier, J., Rovira, C., Gorostiza, P., (2018). Long distance electron transfer through the aqueous solution between redox partner proteins Nature Communications 9, (1), 5157
Despite the importance of electron transfer between redox proteins in photosynthesis and respiration, the inter-protein electron transfer rate between redox partner proteins has never been measured as a function of their separation in aqueous solution. Here, we use electrochemical tunneling spectroscopy to show that the current between two protein partners decays along more than 10 nm in the solution. Molecular dynamics simulations reveal a reduced ionic density and extended electric field in the volume confined between the proteins. The distance-decay factor and the calculated local barrier for electron transfer are regulated by the electrochemical potential applied to the proteins. Redox partners could use electrochemically gated, long distance electron transfer through the solution in order to conciliate high specificity with weak binding, thus keeping high turnover rates in the crowded environment of cells.
Bregestovski, Piotr, Maleeva, Galyna, Gorostiza, Pau, (2018). Light-induced regulation of ligand-gated channel activity British Journal of Pharmacology 175, (11), 1892-1902
The control of ligand-gated receptors with light using photochromic compounds has evolved from the first handcrafted examples to accurate, engineered receptors, whose development is supported by rational design, high-resolution protein structures, comparative pharmacology and molecular biology manipulations. Photoswitchable regulators have been designed and characterized for a large number of ligand-gated receptors in the mammalian nervous system, including nicotinic acetylcholine, glutamate and GABA receptors. They provide a well-equipped toolbox to investigate synaptic and neuronal circuits in all-optical experiments. This focused review discusses the design and properties of these photoswitches, their applications and shortcomings and future perspectives in the field.
Casanellas, Ignasi, Lagunas, Anna, Tsintzou, Iro, Vida, Yolanda, Collado, Daniel, Pérez-Inestrosa, Ezequiel, Rodríguez-Pereira, Cristina, Magalhaes, Joana, Gorostiza, Pau, Andrades, José A., Becerra, José, Samitier, Josep, (2018). Dendrimer-based uneven nanopatterns to locally control surface adhesiveness: A method to direct chondrogenic differentiation Journal of Visualized Experiments Bioengineering, (131), e56347
Cellular adhesion and differentiation is conditioned by the nanoscale disposition of the extracellular matrix (ECM) components, with local concentrations having a major effect. Here we present a method to obtain large-scale uneven nanopatterns of arginine-glycine-aspartic acid (RGD)-functionalized dendrimers that permit the nanoscale control of local RGD surface density. Nanopatterns are formed by surface adsorption of dendrimers from solutions at different initial concentrations and are characterized by water contact angle (CA), X-ray photoelectron spectroscopy (XPS), and scanning probe microscopy techniques such as scanning tunneling microscopy (STM) and atomic force microscopy (AFM). The local surface density of RGD is measured using AFM images by means of probability contour maps of minimum interparticle distances and then correlated with cell adhesion response and differentiation. The nanopatterning method presented here is a simple procedure that can be scaled up in a straightforward manner to large surface areas. It is thus fully compatible with cell culture protocols and can be applied to other ligands that exert concentration-dependent effects on cells.
Keywords: Bioengineering, Dendrimer, Nanopattern, Arginine-Glycine-Aspartic Acid (RGD), Atomic Force Microscopy (AFM), Cell Adhesion, Mesenchymal Stem Cells (Mscs), Chondrogenesis
Calvé, Pablo, Gorostiza, Pau, (2017). Estrategias optogenéticas y fotofarmacológicas para restablecer la visión Visión , 51, 6-13
La mayoría de los casos de ceguera están causados por defectos en el ojo. Generalmente, estas alteraciones se producen por daños en las vías ópticas que conducen a la retina y son necesarias para el enfoque de las imágenes. A día de hoy, es posible tratar y curar estos impedimentos ópticos. Por ejemplo, la cirugía de cataratas para extraer una lente opaca y reemplazarla con una lente artificial se lleva a cabo rutinariamente en muchas partes del mundo y los trasplantes de córnea con córneas naturales o artificiales comúnmente tienen éxito. Sin embargo, existen casos de ceguera que afectan a un porcentaje considerable de la población y no disponen de tratamiento. La mayor parte de las cegueras incurables son debidas a las enfermedades neurodegenerativas de la retina, que se caracterizan, la mayoría de las veces, por pérdida de las células fotorreceptoras. En estas enfermedades, los fotorreceptores se dañan y mueren en un proceso de apoptosis que eventualmente provoca la ceguera. Sin embargo, las neuronas situadas en las capas internas de la retina permanecen intactas durante un periodo de tiempo prolongado, antes de que la retina sufra procesos de remodelización en las etapas finales de la enfermedad. Entre las enfermedades neurodegenerativas de la retina, la retinosis pigmentaria y la degeneración macular asociada a la edad son las más comunes. De este modo, debido a que las neurodegeneraciones retinianas provocan afectaciones en la visión y pueden inducir ceguera completa en los casos más graves, es necesario buscar y estudiar nuevos tratamientos terapéuticos. Hoy en día, muchos laboratorios de investigación están desarrollando terapias para este tipo de enfermedades, dirigidas a restaurar la función de las células fotorreceptoras en el ojo ciego o bien a sustituir la pérdida de la función fotorreceptora, pretendiendo que las neuronas retinianas restantes sean directamente sensibles a la luz. Estas aproximaciones terapéuticas engloban desde prótesis electrónicas hasta células madre y terapia génica.
Ruiz, Marta P., Aragones, Albert C., Camarero, Nuria, Vilhena, J. G., Ortega, Maria, Zotti, Linda Angela, Perez, Ruben, Cuevas, Juan Carlos, Gorostiza, Pau, Díez-Pérez, Ismael, (2017). Bioengineering a single-protein junction Journal of the American Chemical Society 139, (43), 15337–15346
Bioelectronics moves toward designing nanoscale electronic platforms that allow in vivo determinations. Such devices require interfacing complex biomolecular moieties as the sensing units to an electronic platform for signal transduction. Inevitably, a systematic design goes through a bottom-up understanding of the structurally related electrical signatures of the biomolecular circuit, which will ultimately lead us to tailor its electrical properties. Toward this aim, we show here the first example of bioengineered charge transport in a single-protein electrical contact. The results reveal that a single point-site mutation at the docking hydrophobic patch of a Cu-azurin causes minor structural distortion of the protein blue Cu site and a dramatic change in the charge transport regime of the single-protein contact, which goes from the classical Cu-mediated two-step transport in this system to a direct coherent tunneling. Our extensive spectroscopic studies and molecular-dynamics simulations show that the proteins' folding structures are preserved in the single-protein junction. The DFT-computed frontier orbital of the relevant protein segments suggests that the Cu center participation in each protein variant accounts for the different observed charge transport behavior. This work is a direct evidence of charge transport control in a protein backbone through external mutagenesis and a unique nanoscale platform to study structurally related biological electron transfer.
Gómez-Santacana, Xavier, Pittolo, Silvia, Rovira, Xavier, Lopez, Marc, Zussy, Charleine, Dalton, James A. R., Faucherre, Adèle, Jopling, Chris, Pin, Jean-Philippe, Ciruela, Francisco, Goudet, Cyril, Giraldo, Jesús, Gorostiza, Pau, Llebaria, Amadeu, (2017). Illuminating phenylazopyridines to photoswitch metabotropic glutamate receptors: From the flask to the animals ACS Central Science , 3, (1), 81-91
Phenylazopyridines are photoisomerizable compounds with high potential to control biological functions with light. We have obtained a series of phenylazopyridines with light dependent activity as negative allosteric modulators (NAM) of metabotropic glutamate receptor subtype 5 (mGlu5). Here we describe the factors needed to achieve an operational molecular photoisomerization and its effective translation into in vitro and in vivo receptor photoswitching, which includes zebrafish larva motility and the regulation of the antinociceptive effects in mice. The combination of light and some specific phenylazopyridine ligands displays atypical pharmacological profiles, including light-dependent receptor overactivation, which can be observed both in vitro and in vivo. Remarkably, the localized administration of light and a photoswitchable compound in the peripheral tissues of rodents or in the brain amygdalae results in an illumination-dependent analgesic effect. The results reveal a robust translation of the phenylazopyridine photoisomerization to a precise photoregulation of biological activity.
López-Martínez, Montserrat, Artés, Juan Manuel, Sarasso, Veronica, Carminati, Marco, Díez-Pérez, Ismael, Sanz, Fausto, Gorostiza, Pau, (2017). Differential electrochemical conductance imaging at the nanoscale Small 13, (36), 1700958
Electron transfer in proteins is essential in crucial biological processes. Although the fundamental aspects of biological electron transfer are well characterized, currently there are no experimental tools to determine the atomic-scale electronic pathways in redox proteins, and thus to fully understand their outstanding efficiency and environmental adaptability. This knowledge is also required to design and optimize biomolecular electronic devices. In order to measure the local conductance of an electrode surface immersed in an electrolyte, this study builds upon the current–potential spectroscopic capacity of electrochemical scanning tunneling microscopy, by adding an alternating current modulation technique. With this setup, spatially resolved, differential electrochemical conductance images under bipotentiostatic control are recorded. Differential electrochemical conductance imaging allows visualizing the reversible oxidation of an iron electrode in borate buffer and individual azurin proteins immobilized on atomically flat gold surfaces. In particular, this method reveals submolecular regions with high conductance within the protein. The direct observation of nanoscale conduction pathways in redox proteins and complexes enables important advances in biochemistry and bionanotechnology.
Keywords: Differential electrochemical conductance, ECSTM, Electron transport pathway, Iron passivation, Redox metalloproteins
Gómez-Santacana, Xavier, Dalton, James A. R., Rovira, Xavier, Pin, Jean Philippe, Goudet, Cyril, Gorostiza, Pau, Giraldo, Jesús, Llebaria, Amadeu, (2017). Positional isomers of bispyridine benzene derivatives induce efficacy changes on mGlu5 negative allosteric modulation European Journal of Medicinal Chemistry 127, 567-576
Modulation of metabotropic glutamate receptor 5 (mGlu5) with partial allosteric antagonists has received increased interest due to their favourable in vivo activity profiles compared to the unfavourable side-effects of full inverse agonists. Here we report on a series of bispyridine benzene derivatives with a functional molecular switch affecting antagonistic efficacy, shifting from inverse agonism to partial antagonism with only a single change in the substitution pattern of the benzene ring. These efficacy changes are explained through computational docking, revealing two different receptor conformations of different energetic stability and different positional isomer binding preferences.
Keywords: mGlu5, Isomers, Partial efficacy, NAM, Antagonist, Inverse agonist
Terni, Beatrice, Pacciolla, Paolo, Masanas, Helena, Gorostiza, Pau, Llobet, Artur, (2017). Tight temporal coupling between synaptic rewiring of olfactory glomeruli and the emergence of odor-guided behavior in Xenopus tadpoles Journal of Comparative Neurology , 525, (17), 3769-3783
Olfactory sensory neurons (OSNs) are chemoreceptors that establish excitatory synapses within glomeruli of the olfactory bulb. OSNs undergo continuous turnover throughout life, causing the constant replacement of their synaptic contacts. Using Xenopus tadpoles as an experimental system to investigate rewiring of glomerular connectivity, we show that novel OSN synapses can transfer information immediately after formation, mediating olfactory-guided behavior. Tadpoles recover the ability to detect amino acids 4 days after bilateral olfactory nerve transection. Restoration of olfactory-guided behavior depends on the efficient reinsertion of OSNs to the olfactory bulb. Presynaptic terminals of incipient synaptic contacts generate calcium transients in response to odors, triggering long lasting depolarization of olfactory glomeruli. The functionality of reconnected terminals relies on well-defined readily releasable and cytoplasmic vesicle pools. The continuous growth of non-compartmentalized axonal processes provides a vesicle reservoir to nascent release sites, which contrasts to the gradual development of cytoplasmic vesicle pools in conventional excitatory synapses. The immediate availability of fully functional synapses upon formation supports an age-independent contribution of OSNs to the generation of odor maps.
Keywords: Olfactory receptor neurons, Olfactory bulb, Presynaptic terminals, RRID:SCR_013731, RRID:SCR_007164, RRID: AB-887824, RRID: AB-221570, Synaptic vesicles
Rovira, Xavier, Trapero, Ana, Pittolo, Silvia, Zussy, Charleine, Faucherre, Adèle, Jopling, Chris, Giraldo, Jesús, Pin, Jean-Philippe, Gorostiza, Pau, Goudet, Cyril, Llebaria, Amadeu, (2016). OptoGluNAM4.1, a Photoswitchable allosteric antagonist for real-time control of mGlu4 receptor activity Cell Chemical Biology 23, (8), 929-934
OptoGluNAM4.1, a negative allosteric modulator (NAM) of metabotropic glutamate receptor 4 (mGlu4) contains a reactive group that covalently binds to the receptor and a blue-light-activated, fast-relaxing azobenzene group that allows reversible receptor activity photocontrol in vitro and in vivo. OptoGluNAM4.1 induces light-dependent behavior in zebrafish and reverses the activity of the mGlu4 agonist LSP4-2022 in a mice model of chronic pain, defining a photopharmacological tool to better elucidate the physiological roles of the mGlu4 receptor in the nervous system.
Izquierdo-Serra, M., Bautista-Barrufet, A., Trapero, A., Garrido-Charles, A., Diaz-Tahoces, A., Camarero, N., Pittolo, S., Valbuena, S., Perez-Jimenez, A., Gay, M., Garcia-Moll, A., Rodriguez-Escrich, C., Lerma, J., De La Villa, P., Fernandez, E., Pericas, M. A., Llebaria, A., Gorostiza, P., (2016). Optical control of endogenous receptors and cellular excitability using targeted covalent photoswitches Nature Communications 7, 12221
Light-regulated drugs allow remotely photoswitching biological activity and enable plausible therapies based on small molecules. However, only freely diffusible photochromic ligands have been shown to work directly in endogenous receptors and methods for covalent attachment depend on genetic manipulation. Here we introduce a chemical strategy to covalently conjugate and photoswitch the activity of endogenous proteins and demonstrate its application to the kainate receptor channel GluK1. The approach is based on photoswitchable ligands containing a short-lived, highly reactive anchoring group that is targeted at the protein of interest by ligand affinity. These targeted covalent photoswitches (TCPs) constitute a new class of light-regulated drugs and act as prosthetic molecules that photocontrol the activity of GluK1-expressing neurons, and restore photoresponses in degenerated retina. The modularity of TCPs enables the application to different ligands and opens the way to new therapeutic opportunities.
A. R. Dalton, J., Lans, I., Rovira, X., Malhaire, F., Gómez-Santacana, X., Pittolo, S., Gorostiza, P., Llebaria, A., Goudet, C., Pin, J-P., Giraldo, J., (2016). Shining light on an mGlu5 photoswitchable NAM: A theoretical perspective Current Neuropharmacology , 14, (5), 441-454
Metabotropic glutamate receptors (mGluRs) are important drug targets because of their involvement in several neurological diseases. Among mGluRs, mGlu5 is a particularly high-profile target because its positive or negative allosteric modulation can potentially treat schizophrenia or anxiety and chronic pain, respectively. Here, we computationally and experimentally probe the functional binding of a novel photoswitchable mGlu5 NAM, termed alloswitch-1, which loses its NAM functionality under violet light. We show alloswitch-1 binds deep in the allosteric pocket in a similar fashion to mavoglurant, the co-crystallized NAM in the mGlu5 transmembrane domain crystal structure. Alloswitch-1, like NAM 2-Methyl-6-(phenylethynyl)pyridine (MPEP), is significantly affected by P655M mutation deep in the allosteric pocket, eradicating its functionality. In MD simulations, we show alloswitch-1 and MPEP stabilize the co-crystallized water molecule located at the bottom of the allosteric site that is seemingly characteristic of the inactive receptor state. Furthermore, both NAMs form H-bonds with S809 on helix 7, which may constitute an important stabilizing interaction for NAM-induced mGlu5 inactivation. Alloswitch-1, through isomerization of its amide group from trans to cis is able to form an additional interaction with N747 on helix 5. This may be an important interaction for amide-containing mGlu5 NAMs, helping to stabilize their binding in a potentially unusual cis-amide state. Simulated conformational switching of alloswitch-1 in silico suggests photoisomerization of its azo group from trans to cis may be possible within the allosteric pocket. However, photoexcited alloswitch-1 binds in an unstable fashion, breaking H-bonds with the protein and destabilizing the co-crystallized water molecule. This suggests photoswitching may have destabilizing effects on mGlu5 binding and functionality.
Keywords: Allosteric modulation, Docking, Metabotropic glutamate receptor, Molecular dynamics, Mutation, Protein structure, Transmembrane domain
Martín-Quirós, Andrés, Nevola, Laura, Eckelt, Kay, Madurga, Sergio, Gorostiza, Pau, Giralt, Ernest, (2015). Absence of a stable secondary structure is not a limitation for photoswitchable inhibitors of β-Arrestin/β-Adaptin 2 protein-protein interaction Chemistry & Biology , 22, (1), 31-37
Many protein-protein interactions (PPIs) are mediated by short, often helical, linear peptides. Molecules mimicking these peptides have been used to inhibit their PPIs. Recently, photoswitchable peptides with little secondary structure have been developed as modulators of clathrin-mediated endocytosis. Here we perform a systematic analysis of a series of azobenzene-crosslinked peptides based on a β-arrestin P-long 20-mer peptide (BAP-long) sequence to assess the relevance of secondary structure in their interaction with β-adaptin 2 and to identify the design requirements for photoswitchable inhibitors of PPI (PIPPIs). We observe that flexible structures show a greater inhibitory capacity and enhanced photoswitching ability and that the absence of helical structures in free inhibitor peptide is not a limitation for PIPPI candidates. Therefore, our PIPPIs expand the field of potential inhibitors of PPIs to the wide group of flexible peptides, and we argue against using a stable secondary structure as a sole criterion when designing PIPPI candidates.
Gascón-Moya, Marta, Pejoan, Arnau, Izquierdo-Serra, M., Pittolo, Silvia, Cabrè, Gisela, Hernando, Jordi, Alibés, Ramon, Gorostiza, Pau, Busque, Felix, (2015). An optimized glutamate receptor photoswitch with sensitized azobenzene isomerization Journal of Organic Chemistry 80, (20), 9915-9925
A new azobenzene-based photoswitch, 2, has been designed to enable optical control of ionotropic glutamate receptors in neurons via sensitized two-photon excitation with NIR light. In order to develop an efficient and versatile synthetic route for this molecule, a modular strategy is described which relies on the use of a new linear fully protected glutamate derivative stable in basic media. The resulting compound undergoes one-photon trans-cis photoisomerization via two different mechanisms: direct excitation of its azoaromatic unit, and irradiation of the pyrene sensitizer, a well known two-photon sensitive chromophore. Moreover, 2 presents large thermal stability of its cis isomer, in contrast to other two-photon responsive switches relying on the intrinsic non-linear optical properties of push-pull substituted azobenzenes. As a result, the molecular system developed herein is a very promising candidate for evoking large photoinduced biological responses during the multiphoton operation of neuronal glutamate receptors with NIR light, which require accumulation of the protein-bound cis state of the switch upon repeated illumination. A new azobenzene-based photoswitch, 2, has been designed to enable optical control of ionotropic glutamate receptors in neurons via sensitized two-photon excitation with NIR light. In order to develop an efficient and versatile synthetic route for this molecule, a modular strategy is described which relies on the use of a new linear fully protected glutamate derivative stable in basic media. The resulting compound undergoes one-photon trans-cis photoisomerization via two different mechanisms: direct excitation of its azoaromatic unit, and irradiation of the pyrene sensitizer, a well known two-photon sensitive chromophore. Moreover, 2 presents large thermal stability of its cis isomer, in contrast to other two-photon responsive switches relying on the intrinsic non-linear optical properties of push-pull substituted azobenzenes. As a result, the molecular system developed herein is a very promising candidate for evoking large photoinduced biological responses during the multiphoton operation of neuronal glutamate receptors with NIR light, which require accumulation of the protein-bound cis state of the switch upon repeated illumination.
Giannotti, M. I., Cabeza de Vaca, Israel, Artés, Juan Manuel, Sanz, Fausto, Guallar, Victor, Gorostiza, Pau, (2015). Direct measurement of the nanomechanical stability of a redox protein active site and its dependence upon metal binding Journal of Physical Chemistry B , 119, (36), 12050-12058
The structural basis of the low reorganization energy of cupredoxins has long been debated. These proteins reconcile a conformationally heterogeneous and exposed metal-chelating site with the highly rigid copper center required for efficient electron transfer. Here we combine single-molecule mechanical unfolding experiments with statistical analysis and computer simulations to show that the metal-binding region of apo-azurin is mechanically flexible and that high mechanical stability is imparted by copper binding. The unfolding pathway of the metal site depends on the pulling residue and suggests that partial unfolding of the metal binding site could be facilitated by the physical interaction with certain regions of the redox protein. The structural basis of the low reorganization energy of cupredoxins has long been debated. These proteins reconcile a conformationally heterogeneous and exposed metal-chelating site with the highly rigid copper center required for efficient electron transfer. Here we combine single-molecule mechanical unfolding experiments with statistical analysis and computer simulations to show that the metal-binding region of apo-azurin is mechanically flexible and that high mechanical stability is imparted by copper binding. The unfolding pathway of the metal site depends on the pulling residue and suggests that partial unfolding of the metal binding site could be facilitated by the physical interaction with certain regions of the redox protein.
Eckelt, Kay, Masanas, Helena, Llobet, Artur, Gorostiza, P., (2014). Automated high-throughput measurement of body movements and cardiac activity of Xenopus tropicalis tadpoles Journal of Biological Methods , 1, (2), e9
Xenopus tadpoles are an emerging model for developmental, genetic and behavioral studies. A small size, optical accessibility of most of their organs, together with a close genetic and structural relationship to humans make them a convenient experimental model. However, there is only a limited toolset available to measure behavior and organ function of these animals at medium or high-throughput. Herein, we describe an imaging-based platform to quantify body and autonomic movements of Xenopus tropicalis tadpoles of advanced developmental stages. Animals alternate periods of quiescence and locomotor movements and display buccal pumping for oxygen uptake from water and rhythmic cardiac movements. We imaged up to 24 animals in parallel and automatically tracked and quantified their movements by using image analysis software. Animal trajectories, moved distances, activity time, buccal pumping rates and heart beat rates were calculated and used to characterize the effects of test compounds. We evaluated the effects of propranolol and atropine, observing a dose-dependent bradycardia and tachycardia, respectively. This imaging and analysis platform is a simple, cost-effective high-throughput in vivo assay system for genetic, toxicological or pharmacological characterizations.
Keywords: Xenopus tropicalis, Animal behavior, Cardiac imaging, Motion analysis, Animal tracking, Hhigh-throughput in vivo assay
Pittolo, Silvia, Gómez-Santacana, Xavier, Eckelt, Kay, Rovira, Xavier, Dalton, James, Goudet, Cyril, Pin, Jean-Philippe, Llobet, Artur, Giraldo, Jesús, Llebaria, Amadeu, Gorostiza, Pau, (2014). An allosteric modulator to control endogenous G protein-coupled receptors with light Nature Chemical Biology , 10, (10), 813-815
Controlling drug activity with light offers the possibility of enhancing pharmacological selectivity with spatial and temporal regulation, thus enabling highly localized therapeutic effects and precise dosing patterns. Here we report on the development and characterization of what is to our knowledge the first photoswitchable allosteric modulator of a G protein–coupled receptor. Alloswitch-1 is selective for the metabotropic glutamate receptor mGlu5 and enables the optical control of endogenous mGlu5 receptors.
Izquierdo-Serra, M., Gascón-Moya, Marta, Hirtz, Jan J., Pittolo, Silvia, Poskanzer, Kira E., Ferrer, Eric, Alibés, Ramon, Busque, Felix, Yuste, Rafael, Hernando, Jordi, Gorostiza, Pau, (2014). Two-photon neuronal and astrocytic stimulation of azobenzene-based photoswitches Journal of the American Chemical Society American Chemical Society 136, (24), 8693-8701
Synthetic photochromic compounds can be designed to control a variety of proteins and their biochemical functions in living cells, but the high spatiotemporal precision and tissue penetration of two-photon stimulation has never been investigated in these molecules. Here we demonstrate two-photon excitation of azobenzene-based protein switches, and versatile strategies to enhance their photochemical responses. This enables new applications to control the activation of neurons and astrocytes with cellular and subcellular resolution.
Bautista-Barrufet, A., López-Gallego, F., Rojas-Cervellera, V., Rovira, C., Pericàs, M. A., Guisán, J. M., Gorostiza, P., (2014). Optical control of enzyme enantioselectivity in solid phase ACS Catalysis , 4, (3), 1004-1009
A lipase was immobilized on transparent agarose microspheres and genetically engineered to specifically anchor photochromic molecules into its catalytic site. Several combinations of azobenzene and spiropyran groups were conjugated to cysteines introduced at different positions near the active center. Light modulated the catalytic properties of the resulting solid bioconjugates, and such modulation depended on both the nature of the photochromic compound and the anchoring position. Covalent anchoring of azobenzene derivatives to the residue 295 of the lipase 2 from Bacillus thermocathenolatus triggered lipase preference for the S isomer under UV light, whereas visible light promoted preference for the R isomer. Molecular dynamics simulations indicate that conjugating photochromic compounds into the catalytic cavity allows manipulating the steric hindrance and binding energy of the substrates, leading to an enantioselective molecular fit in certain cases. Using this approach, we report for the first time the control of enzyme properties using light in the solid phase. A lipase was immobilized on transparent agarose microspheres and genetically engineered to specifically anchor photochromic molecules into its catalytic site. Several combinations of azobenzene and spiropyran groups were conjugated to cysteines introduced at different positions near the active center. Light modulated the catalytic properties of the resulting solid bioconjugates, and such modulation depended on both the nature of the photochromic compound and the anchoring position. Covalent anchoring of azobenzene derivatives to the residue 295 of the lipase 2 from Bacillus thermocathenolatus triggered lipase preference for the S isomer under UV light, whereas visible light promoted preference for the R isomer. Molecular dynamics simulations indicate that conjugating photochromic compounds into the catalytic cavity allows manipulating the steric hindrance and binding energy of the substrates, leading to an enantioselective molecular fit in certain cases. Using this approach, we report for the first time the control of enzyme properties using light in the solid phase.
Artés, Juan M., López-Martínez, Montserrat, Díez-Pérez, Ismael, Sanz, Fausto, Gorostiza, Pau, (2014). Conductance switching in single wired redox proteins Small 10, (13), 2537-2541
Switching events in the current flowing through individual redox proteins, (azurin) spontaneously wired between two electrodes, are studied using an electrochemical scanning tunneling microscope (ECSTM). These switching events in the current–time trace are characterized using conductance histograms, and reflect the intrinsic redox thermodynamic dispersion in the azurin population. This conductance switching may pose limitations to miniaturizing redox protein-based devices.
Keywords: Bioelectronics, Protein transistors, Molecular junctions, Switches, STM
Lagunas, A., Garcia, A., Artés, J. M., Vida, Y., Collado, D., Pérez-Inestrosa, E., Gorostiza, P., Claros, S., Andrades, J. A., Samitier, J., (2014). Large-scale dendrimer-based uneven nanopatterns for the study of local arginine-glycine-aspartic acid (RGD) density effects on cell adhesion Nano Research , 7, (3), 399-409
Cell adhesion processes are governed by the nanoscale arrangement of the extracellular matrix (ECM), being more affected by local rather than global concentrations of cell adhesive ligands. In many cell-based studies, grafting of dendrimers on surfaces has shown the benefits of the local increase in concentration provided by the dendritic configuration, although the lack of any reported surface characterization has limited any direct correlation between dendrimer disposition and cell response. In order to establish a proper correlation, some control over dendrimer surface deposition is desirable. Here, dendrimer nanopatterning has been employed to address arginine-glycine-aspartic acid (RGD) density effects on cell adhesion. Nanopatterned surfaces were fully characterized by atomic force microscopy (AFM), scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS), showing that tunable distributions of cell adhesive ligands on the surface are obtained as a function of the initial dendrimer bulk concentration. Cell experiments showed a clear correlation with dendrimer surface layout: Substrates presenting regions of high local ligand density resulted in a higher percentage of adhered cells and a higher degree of maturation of focal adhesions (FAs). Therefore, dendrimer nanopatterning is presented as a suitable and controlled approach to address the effect of local ligand density on cell response. Moreover, due to the easy modification of dendrimer peripheral groups, dendrimer nanopatterning can be further extended to other ECM ligands having density effects on cells.
Keywords: Arginine-glycine-aspartic acid, Atomic force microscopy, Cell adhesion, Dendrimer, Focal adhesions, Scanning tunneling microscopy
Bahamonde, María Isabel, Taura, Jaume, Paoletta, Silvia, Gakh, Andrei Alexandrovich, Chakraborty, Saibal, Hernando, Jordi, Fernández-Dueñas, Víctor, Jacobson, Kenneth A., Gorostiza, Pau, Ciruela, Francisco, (2014). Photomodulation of G protein-coupled adenosine receptors by a novel light-switchable ligand Bioconjugate Chemistry , American Chemical Society 25, (10), 1847-1854
The adenosinergic system operates through G protein-coupled adenosine receptors, which have become promising therapeutic targets for a wide range of pathological conditions. However, the ubiquity of adenosine receptors and the eventual lack of selectivity of adenosine-based drugs have frequently diminished their therapeutic potential. Accordingly, here we aimed to develop a new generation of light-switchable adenosine receptor ligands that change their intrinsic activity upon irradiation, thus allowing the spatiotemporal control of receptor functioning (i.e. receptor activation/inactivation dependent on location and timing). Therefore, we synthesized an orthosteric, photoisomerizable and non-selective adenosine receptor agonist, nucleoside derivative MRS5543 containing an aryl diazo linkage on the N6 substituent, which in the dark (relaxed isomer) behaved as a full adenosine A3 receptor (A3R) and partial adenosine A2A receptor (A2AR) agonist. Conversely, upon photoisomerization with blue light (460 nm), it remained a full A3R agonist but became an A2AR antagonist. Interestingly, molecular modeling suggested that structural differences encountered within the third extracellular loop of each receptor could modulate the intrinsic, receptor subtype-dependent, activity. Overall, the development of adenosine receptor ligands with photoswitchable activity expands the pharmacological toolbox in support of research and possibly opens new pharmacotherapeutic opportunities. The adenosinergic system operates through G protein-coupled adenosine receptors, which have become promising therapeutic targets for a wide range of pathological conditions. However, the ubiquity of adenosine receptors and the eventual lack of selectivity of adenosine-based drugs have frequently diminished their therapeutic potential. Accordingly, here we aimed to develop a new generation of light-switchable adenosine receptor ligands that change their intrinsic activity upon irradiation, thus allowing the spatiotemporal control of receptor functioning (i.e. receptor activation/inactivation dependent on location and timing). Therefore, we synthesized an orthosteric, photoisomerizable and non-selective adenosine receptor agonist, nucleoside derivative MRS5543 containing an aryl diazo linkage on the N6 substituent, which in the dark (relaxed isomer) behaved as a full adenosine A3 receptor (A3R) and partial adenosine A2A receptor (A2AR) agonist. Conversely, upon photoisomerization with blue light (460 nm), it remained a full A3R agonist but became an A2AR antagonist. Interestingly, molecular modeling suggested that structural differences encountered within the third extracellular loop of each receptor could modulate the intrinsic, receptor subtype-dependent, activity. Overall, the development of adenosine receptor ligands with photoswitchable activity expands the pharmacological toolbox in support of research and possibly opens new pharmacotherapeutic opportunities.
Artés, J. M., López-Martínez, M., Díez-Pérez, I., Sanz, F., Gorostiza, P., (2014). Nanoscale charge transfer in redox proteins and DNA: Towards biomolecular electronics Electrochimica Acta 140, 83-95
Understanding how charges move through and between biomolecules is a fundamental question that constitutes the basis for many biological processes. On the other hand, it has potential applications in the design of sensors based on biomolecules and single molecule devices. In this review we introduce the study of the electron transfer (ET) process in biomolecules, providing an overview of the fundamental theory behind it and the different experimental approaches. The ET in proteins is introduced by reviewing a complete electronic characterization of a redox protein (azurin) using electrochemical scanning tunnelling microscopy (ECSTM). The ET process in DNA is overviewed and results from different experimental approaches are discussed. Finally, future directions in the study of the ET process in biomolecules are introduced as well as examples of possible technological applications.
Keywords: Bioelectrochemistry, Biomolecular electronics, Charge transfer, Nanobiodevice, Single-molecule junction
Gomez-Santacana, X., Rovira, X., Dalton, J. A., Goudet, C., Pin, J. P., Gorostiza, P., Giraldo, J., Llebaria, A., (2014). A double effect molecular switch leads to a novel potent negative allosteric modulator of metabotropic glutamate receptor 5 MedChemComm , 5, (10), 1548-1554
Compounds that modulate the function of G-protein-coupled receptors (GPCRs) by binding to their allosteric sites are of potential interest for the treatment of multiple CNS and non-CNS disorders. Allosteric ligands can act either as positive (PAM), negative (NAM), or silent (SAM) receptor modulators and have numerous advantages over classic orthosteric compounds, including improved GPCR-subtype selectivity; the capacity to adapt to physiological conditions; and better safety profiles. Despite these benefits, allosteric modulators are difficult to design and optimize and are often prone to "molecular switching": a structural phenomenon by which very subtle chemical variations in the ligand result in unexpected changes in selectivity profiles or pharmacology, changing PAMs to NAMs or vice versa. Here, we report the discovery of a nanomolar and subtype selective NAM of metabotropic glutamate receptor 5 (mGlu5) through a targeted "double effect molecular switch" of a potent mGlu4 PAM, and suggests a promising approach towards the discovery of novel mGluR allosteric modulators.
Bautista-Barrufet, Antoni, Izquierdo-Serra, M., Gorostiza, Pau, (2014). Photoswitchable Ion Channels and Receptors Advances in Atom and Single Molecule Machines Novel Approaches for Single Molecule Activation and Detection (ed. Benfenati, Fabio, Di Fabrizio, Enzo, Torre, Vincent), Springer Berlin Heidelberg , 169-188
The development of photochromic and photoswitchable ligands for ion channels and receptors has made important contributions to optopharmacology and optogenetic pharmacology. These compounds provide new tools to study ion channel proteins and to understand their function and pathological implications. Here, we describe the design, operation, and applications of the available photoswitches, with special emphasis on ligand- and voltage-gated channels.
Gorostiza, Pau, Arosio, Daniele, Bregestovski, Piotr, (2013). Molecular probes and switches for functional analysis of receptors, ion channels and synaptic networks Frontiers in Molecular Neuroscience 6, (Article 48), 1-2
Keywords: Optogenetics, Genetically encoded biosensors, Chloride imaging, pH monitoring, Intracellular Ca, Optopharmacology, Photochromic ligands, Photoswitchable tethered ligands
Izquierdo-Serra, Mercè, Trauner, Dirk, Llobet, Artur, Gorostiza, Pau, (2013). Optical modulation of neurotransmission using calcium photocurrents through the ion channel LiGluR Frontiers in Molecular Neuroscience 6, (Article 3), 1-6
A wide range of light-activated molecules (photoswitches and phototriggers) have been used to the study of computational properties of an isolated neuron by acting pre and postsynaptically. However, new tools are being pursued to elicit a presynaptic calcium influx that triggers the release of neurotransmitters, most of them based in calcium-permeable Channelrhodopsin-2 mutants. Here we describe a method to control exocytosis of synaptic vesicles through the use of a light-gated glutamate receptor (LiGluR), which has recently been demonstrated that supports secretion by means of calcium influx in chromaffin cells. Expression of LiGluR in hippocampal neurons enables reversible control of neurotransmission with light, and allows modulating the firing rate of the postsynaptic neuron with the wavelength of illumination. This method may be useful for the determination of the complex transfer function of individual synapses.
Keywords: Calcium, Neurotransmission, Optogenetics, Neural coding, Firing rate, Optical control, Synaptic transfer function
Nevola, L., Martín-Quirós, A., Eckelt, K., Camarero, N., Tosi, S., Llobet, A., Giralt, E., Gorostiza, P., (2013). Light-regulated stapled peptides to inhibit protein-protein interactions involved in clathrin-mediated endocytosis Angewandte Chemie - International Edition , 52, (30), 7704-7708
Control of membrane traffic: Photoswitchable inhibitors of protein-protein interactions were applied to photoregulate clathrin-mediated endocytosis (CME) in living cells. Traffic light (TL) peptides acting as "stop" and "go" signals for membrane traffic can be used to dissect the role of CME in receptor internalization and in cell growth, division, and differentiation.
Keywords: Clathrin-mediated endocytosis, Optopharmacology, Peptides, Photoswitches, Protein-protein interactions
Izquierdo-Serra, Mercè, Trauner, Dirk, Llobet, Artur, Gorostiza, Pau, (2013). Optical control of calcium-regulated exocytosis Biochimica et Biophysica Acta (BBA) - General Subjects , 1830, (3), 2853-2860
Background Neurons signal to each other and to non-neuronal cells as those in muscle or glands, by means of the secretion of neurotransmitters at chemical synapses. In order to dissect the molecular mechanisms of neurotransmission, new methods for directly and reversibly triggering neurosecretion at the presynaptic terminal are necessary. Here we exploit the calcium permeability of the light-gated channel LiGluR in order to reversibly manipulate cytosolic calcium concentration, thus controlling calcium-regulated exocytosis. Methods Bovine chromaffin cells expressing LiGluR were stimulated with light. Exocytic events were detected by amperometry or by whole-cell patch-clamp to quantify membrane capacitance and calcium influx. Results Amperometry reveals that optical stimulation consistently triggers exocytosis in chromaffin cells. Secretion of catecholamines can be adjusted between zero and several Hz by changing the wavelength of illumination. Differences in secretion efficacy are found between the activation of LiGluR and native voltage-gated calcium channels (VGCCs). Our results show that the distance between sites of calcium influx and vesicles ready to be released is longer when calcium influx is triggered by LiGluR instead of native VGCCs. Conclusion and general significance LiGluR activation directly and reversibly increases the intracellular calcium concentration. Light-gated calcium influx allows for the first time to control calcium-regulated exocytosis without the need of applying depolarizing solutions or voltage clamping in chromaffin cells. Thus, LiGluR is a useful tool to study the secretory mechanisms and their spatiotemporal patterns in neurotransmission, and opens a window to study other calcium-dependent processes such as muscular contraction or cell migration.
Keywords: Optical control, Calcium, Exocytosis, Light-gated glutamate receptor (LiGluR), Neurotransmission, Optogenetics
Raster, P., Späth, A., Bultakova, S., Gorostiza, P., König, B., Bregestovski, P., (2013). New GABA amides activating GABAA-receptors Beilstein Journal of Organic Chemistry , 9, 406-410
We have prepared a series of new and some literature-reported GABA-amides and determined their effect on the activation of GABA A-receptors expressed in CHO cells. Special attention was paid to the purification of the target compounds to remove even traces of GABA contaminations, which may arise from deprotection steps in the synthesis. GABA-amides were previously reported to be partial, full or superagonists. In our hands these compounds were not able to activate GABAA-receptor channels in whole-cell patch-clamp recordings. New GABA-amides, however, gave moderate activation responses with a clear structure-activity relationship suggesting some of these compounds as promising molecular tools for the functional analysis of GABAA-receptors.
Gorostiza, Pau, (2012). Control celular mediante luz Investigación y Ciencia , 433, 11-12
Artés, Juan M., Díez-Pérez, Ismael, Gorostiza, Pau, (2012). Transistor-like behavior of single metalloprotein junctions Nano Letters 12, (6), 2679-2684
Single protein junctions consisting of azurin bridged between a gold substrate and the probe of an electrochemical tunneling microscope (ECSTM) have been obtained by two independent methods that allowed statistical analysis over a large number of measured junctions. Conductance measurements yield (7.3 ± 1.5) ? 10–6G0 in agreement with reported estimates using other techniques. Redox gating of the protein with an on/off ratio of 20 was demonstrated and constitutes a proof-of-principle of a single redox protein field-effect transistor.
Artés, Juan M., López-Martínez, Montserrat, Giraudet, Arnaud, Díez-Pérez, Ismael, Sanz, Fausto, Gorostiza, Pau, (2012). Current–Voltage characteristics and transition voltage spectroscopy of individual redox proteins Journal of the American Chemical Society 134, (50), 20218-20221
Understanding how molecular conductance depends on voltage is essential for characterizing molecular electronics devices. We reproducibly measured current?voltage characteristics of individual redox-active proteins by scanning tunneling microscopy under potentiostatic control in both tunneling and wired configurations. From these results, transition voltage spectroscopy (TVS) data for individual redox molecules can be calculated and analyzed statistically, adding a new dimension to conductance measurements. The transition voltage (TV) is discussed in terms of the two-step electron transfer (ET) mechanism. Azurin displays the lowest TV measured to date (0.4 V), consistent with the previously reported distance decay factor. This low TV may be advantageous for fabricating and operating molecular electronic devices for different applications. Our measurements show that TVS is a helpful tool for single-molecule ET measurements and suggest a mechanism for gating of ET between partner redox proteins. Understanding how molecular conductance depends on voltage is essential for characterizing molecular electronics devices. We reproducibly measured current?voltage characteristics of individual redox-active proteins by scanning tunneling microscopy under potentiostatic control in both tunneling and wired configurations. From these results, transition voltage spectroscopy (TVS) data for individual redox molecules can be calculated and analyzed statistically, adding a new dimension to conductance measurements. The transition voltage (TV) is discussed in terms of the two-step electron transfer (ET) mechanism. Azurin displays the lowest TV measured to date (0.4 V), consistent with the previously reported distance decay factor. This low TV may be advantageous for fabricating and operating molecular electronic devices for different applications. Our measurements show that TVS is a helpful tool for single-molecule ET measurements and suggest a mechanism for gating of ET between partner redox proteins.
Simao, C., Mas-Torrent, M., Crivillers, N., Lloveras, V., Artés, Juan Manuel, Gorostiza, Pau, Veciana, Jaume, Rovira, C., (2011). A robust molecular platform for non-volatile memory devices with optical and magnetic responses Nature Chemistry , 3, (5), 359-364
Bistable molecules that behave as switches in solution have long been known. Systems that can be reversibly converted between two stable states that differ in their physical properties are particularly attractive in the development of memory devices when immobilized in substrates. Here, we report a highly robust surface-confined switch based on an electroactive, persistent organic radical immobilized on indium tin oxide substrates that can be electrochemically and reversibly converted to the anion form. This molecular bistable system behaves as an extremely robust redox switch in which an electrical input is transduced into optical as well as magnetic outputs under ambient conditions. The fact that this molecular surface switch, operating at very low voltages, can be patterned and addressed locally, and also has exceptionally high long-term stability and excellent reversibility and reproducibility, makes it a very promising platform for non-volatile memory devices.
Keywords: Self-assembled monolayers, Chromophore-based monolayers, Ultrathin platinum films, Carbon free-radicals, Per-million levels, Polychlorotriphenylmethyl radicals, Electron-transfer, Surface, Logic, Quantification
Artés, Juan M., Díez-Pérez, Ismael, Sanz, Fausto, Gorostiza, Pau, (2011). Direct measurement of electron transfer distance decay constants of single redox proteins by electrochemical tunneling spectroscopy ACS Nano 5, (3), 2060-2066
We present a method to measure directly and at the single-molecule level the distance decay constant that characterizes the rate of electron transfer (ET) in redox proteins. Using an electrochemical tunneling microscope under bipotentiostatic control, we obtained current-distance spectroscopic recordings of individual redox proteins confined within a nanometric tunneling gap at a well-defined molecular orientation. The tunneling current decays exponentially, and the corresponding decay constant (β) strongly supports a two-step tunneling ET mechanism. Statistical analysis of decay constant measurements reveals differences between the reduced and oxidized states that may be relevant to the control of ET rates in enzymes and biological electron transport chains.
Keywords: Long-range electron transfer (LRET), Distance decay constant, Single-molecule electrochemistry, Redox enzyme, Metalloprotein, Blue copper protein, Azurin, Electrochemical scanning tunneling microscopy and spectroscopy, Nanoelectrodes, Debye length, Electrochemical charge screening
Gorostiza, P., Isacoff, E.Y., (2011). Photoswitchable ligand-gated ion channels Photosensitive molecules for controlling biological function (ed. Chambers, J. J. , Kramer, R. H.), Springer (Saskatoon, Canada) 55, 267-285
Ligand-activated proteins can be controlled with light by means of synthetic photoisomerizable tethered ligands (PTLs). The application of PTLs to ligand-gated ion channels, including the nicotinic acetylcholine receptor and ionotropic glutamate receptors, is reviewed with emphasis on rational photoswitch design and the mechanisms of optical switching. Recently reported molecular dynamic methods allow simulation with high reliability of novel PTLs for any ligand-activated protein whose structure is known.
Keywords: Nicotinic acetylcholine receptor, Kainate receptor, Glutamate receptor, Photoisomerizable tether ligand (PTL), Optical switch, Nanotoggle, Azobenzene, Neurobiology,, Nanoengineering, Nanomedicine
Caballero-Briones, F., Artes, J. M., Diez-Perez, I., Gorostiza, P., Sanz, F., (2009). Direct observation of the valence band edge by in situ ECSTM-ECTS in p-type Cu2O layers prepared by copper anodization Journal of Physical Chemistry C 113, (3), 1028-1036
Polycrystalline Cu2O layers have been selectively grown by electrochemical anodization of polycrystalline Cu electrodes in an alkaline medium (pH 12.85). Uniform layers with thicknesses around 100 nm have been obtained. Using electrochemical impedance spectroscopy, it was concluded that the Cu2O films behave as a p-type semiconductor. The Mott-Schottky plot gives a value for the flat band potential of U-FB = -255 mV vs silver/silver chloride electrode (SSC), an estimated carrier density N-A = 6.1 x 10(17) cm(-3), and the space charge layer width was calculated to be W-SCL = 9 nm at a band bending of 120 mV. The electronic structure of the Cu vertical bar Cu2O vertical bar electrolyte interface was for the first time probed by in situ electrochemical tunneling spectroscopy. The use of in situ electrochemical scanning tunneling microscopy allows us to directly observed the valence band edge and determine its position against the absolute energy scale to be E-VB = -4.9 eV. Finally, we constructed a quantitative electronic diagram of the Cu vertical bar Cu2O vertical bar electrolyte interface, where the positions of the valence and conduction band edges are depicted, as well as the edge of the previously reported electronic subband.
Keywords: 0.1 m NaOH, Electrochemical tunneling spectroscopy, Cuprous-oxide films, Anodic-oxidation, Electronic-structure, Alkaline-solution, Aqueous-solution, Initial-stages, Passive film, Thin-films
Gorostiza, P., Isacoff, E. Y., (2008). Optical switches for remote and noninvasive control of cell signaling Science 322, (5900), 395-399
Although the identity and interactions of signaling proteins have been studied in great detail, the complexity of signaling networks cannot be fully understood without elucidating the timing and location of activity of individual proteins. To do this, one needs a means for detecting and controlling specific signaling events. An attractive approach is to use light, both to report on and control signaling proteins in cells, because light can probe cells in real time with minimal damage. Although optical detection of signaling events has been successful for some time, the development of the means for optical control has accelerated only recently. Of particular interest is the development of chemically engineered proteins that are directly sensitive to light.
Keywords: Ion channels, Acetylcholine receptor, Glutamate-receptor, Potassium channel, K+ channel, Light, Neurons, Channelrhodopsin-2, Manipulation, Activation
Gorostiza, P., Isacoff, E. Y., (2008). Nanoengineering ion channels for optical control Physiology , 23, (5), 238-247
Chemical modification with photoisomerizable tethered ligands endows proteins with sensitivity to light. These optically actuated proteins are revolutionizing research in biology by making it possible to manipulate biological processes noninvasively and with unprecedented spatiotemporal resolution.
Keywords: -----
Díez-Pérez, Ismael, Guell, Aleix Garcia, Sanz, Fausto, Gorostiza, Pau, (2006). Conductance maps by electrochemical tunneling spectroscopy to fingerprint the electrode electronic structure Analytical Chemistry , 78, (20), 7325-7329
We describe a methodology to perform reliable tunneling spectroscopy in electrochemical media. Sequential in situ tunneling spectra are recorded while the electrochemical potential of the electrode is scanned. Spectroscopic data are presented as conductance maps or conductograms that show the in situ electronic structure of an electrode surface while it undergoes an electrochemical reaction. The conductance map or conductogram represents the redox fingerprint of an electrode/liquid interface in a specific medium and can serve to predict its electrochemical behavior in a quantitative energy scale. The methodology is validated studying the reversible oxidation and passivity of an iron electrode in borate buffer, and we describe the main quantitative information that can be extracted concerning the semiconducting properties of the Fe passive film. This methodology is useful to study heterogeneous catalysis, electrochemical sensing and bioelectronic systems.
Keywords: Passive film, Oxide-film, Stainless-steel, Iron, Microscope, Surfaces, STM, Probes
Díez-Pérez, Ismael, Sanz, Fausto, Gorostiza, Pau, (2006). Electronic barriers in the iron oxide film govern its passivity and redox behavior: Effect of electrode potential and solution pH Electrochemistry Communications , 8, (10), 1595-1602
We have measured in situ the electronic conductance spectra of the passive film formed on an Fe electrode immersed in a borate buffer solution using electrochemical tunneling spectroscopy (ECTS) and electrochemical impedance spectroscopy (EIS) techniques, and we have followed their changes as the electrode is electrochemically oxidized and reduced. We demonstrate that pre-passive Fe(II) oxide and the passive Fe(II)/Fe(III) film, behave as p- and n-type semiconductors, respectively and that their reversible inter-conversion is mediated by the availability of free charge carriers on the electrode surface. ECTS spectra have been also modeled to obtain the main electrochemical kinetic parameters of the electron transfer through both p-Fe(II) and n-Fe(III) oxides at different sample potentials and pHs values. We find that the electronic energy barrier in the oxide and its dependence with electrode potential and solution pH, determine the reactivity and passivity of iron.
Keywords: Electrochemical tunneling spectroscopy, Fe passivity Electronic energy barriers, pH effect on passivity
Díez-Pérez, Ismael, Vericat, Carolina, Gorostiza, Pau, Sanz, Fausto, (2006). The iron passive film breakdown in chloride media may be mediated by transient chloride-induced surface states located within the band gap Electrochemistry Communications , 8, (4), 627-632
Despite its tremendous scientific and economic impact, the mechanism that triggers metal passive film breakdown in the presence of aggressive ions remains under discussion. We have studied the iron passive film in chloride media using X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy and electrochemical tunneling spectroscopy (ECTS). Ex situ XPS reveal that the film consists exclusively of an Fe(III) oxide without chloride content. In situ ECTS has been used to build up conductance maps of the Fe electrode during its electrochemical oxidation in a borate buffer solution and its breakdown when the film is grown in the presence of chloride. This conductograms provide direct and in situ experimental evidence of chloride-induced surface states within the band gap of the oxide film (~3.3eV). These states enable new charge exchange pathways that allow hole capture at the surface of the n-type Fe(III) oxide. The blocking of VB processes that occurs in the iron passive film is no longer present in chloride media, and electrode corrosion can proceed through these new states. We propose a simple 3-step mechanism for the process, in which chloride anions form an oxidizing Fe(II) surface intermediate but do not participate directly in the reaction.
Keywords: Electrochemical tunneling spectroscopy, Electronic band structure, Fe passive film, Aqueous chloride corrosion, Semiconductor decomposition, Interface states
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He or she may have a profile you can read or a picture that is e-mailed to you.For weeks, even months, you may chat back and forth with one another, forming a connection. But ultimately, it's going to happen—your new-found "friend" is going to ask you for money.If your lonely life drags on and you cannot meet your friends and lovers - it is your chance to try your luck in new acquaintances with singles on online dating site No-Scam-Dating.Our dating services make good in ideal dating and quick search of love, romance, friendship and marriage for everyone who wants and needs it!Choose the most interesting for you persons and begin your communication.Use instant messenger and send winks to your friends and lovers on dating site No-Scam-Dating.The greatest number of singles of our dating community has already met their life partner or soul mate and they are happy.Try you chance for being not single any more, find love, romance, tenderness and warmness for you lonely soul.
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Continue Reading The North Atlantic Treaty Organization, known as NATO, faces an existential problem. Rather, it's about Recep Tayyip Erdoğan, the Islamist, dictatorial ruler of Turkey whose policies threaten to undermine this unique alliance of 29 states that has lasted nearly 70 years.


text:
Chantal Gibson's show, A Grammar of Loss, Studies in Erasure, closed early at Open Space due to COVID-19 restrictions, but you can view the show online through the gallery's website and Facebook page. Courtesy Open Space
Victoria art gallery provides Open Space in an online way
View Chantal Gibson's recent show on the web, hear Indigenous stories on Instagram starting Sunday
Don Descoteau
The operators of Open Space have been working to figure out the best way to continue sharing visual art with the community and supporting artists in need in the wake of the COVID-19 crisis.
While plans are still a work in progress, the gallery states that its key goals and focus continue to be, "to share the resources we have as an established artist-run centre to support artists in a time of need; to foster creative ways of engaging and sustaining community in a time of increased isolation; and to collaborate on exciting contemporary art projects that invite us deeper into relationship with the world around us."
As it works to define what that might look like, Open Space is reaching out to the community for suggestions on how to make the arts meaningful at this time. It is encouraging the public to send feedback via email to openspace@openspace.ca.
The sharing of work in a open gallery format may be on hold right now, but one current exhibition by Chantal Gibson entitled A Grammar of Loss – Studies in Erasure continues online, where you can view images of her show up close.
Also, Open Space is launching a new series of land-based livestreams called Online On Land on Instagram, with weekly walks and talks from different sites within Lekwungen and W̱SÁNEĆ territories, where viewers can spend time with and learn from local Indigenous artists, educators and knowledge keepers.
The first livestream happens this Sunday (April 5) at 1 p.m. and features Songhees Nation member and artist Cheryl Bryce. The weekly schedule runs through May 10. Click here and access the stories by clicking on the Open Space logo.
For more information, visit openspace.ca.
editor@mondaymag.com
COVID-19: 'The Ballad of Bonnie Henry' recorded and released
After 37 years, Campbell River Arts Council annual members' show goes online

redpajama_set_name: RedPajamaCommonCrawl


Just Completed, Stunning Modern Construction in the heart of LoHi. 4br/5ba very open duplex with a rare 3 car garage and backyard. Professional designers carefully selected high end modern finishes which includes imported tile, wide plank white oak hardwood flooring, floating stairs, high end Jenn-Air appliance package and modern gas fireplace. All bedrooms are spacious with master boasting a 5-piece master bath with floating tub and large walk in closet. Fully finished basement with recreation area and full bed/bath perfect for guests. Rooftop entertainment room with wet bar, plenty of outdoor seating and big sliding glass doors that step outside to the rooftop patio having a fireplace and downtown views. This property is pre-wired for sound, data, and all thermostats can be controlled by apps that allow you to also control sound, lock and unlock home remotely and the ability to do much more via phone/tablets.


van Walree IC, Hamaker ME, van de Poll-Franse LV, Vos MC, Boll D, van Huis-Tanja LH, Ezendam NPM.
Treatment decision-making in elderly women with ovarian cancer: an age-based comparison.
van Walree IC, van Soolingen NJ, Hamaker ME, Smorenburg CH, Louwers JA, van Huis-Tanja LH.
Int J Gynecol Cancer. 2019 Jan;29(1):158-165. doi: 10.1136/ijgc-2018-000026.
Adherence to surveillance guidelines for colorectal adenomatous polyps in the elderly.
Puylaert CCEM, Koster-van Ree ML, Verhagen MAMT, van Tuyl SAC, Hamaker ME.
Neth J Med. 2018 Oct;76(8):358-364.
Souwer ETD, Hultink D, Bastiaannet E, Hamaker ME, Schiphorst A, Pronk A, van der Bol JM, Steup WH, Dekker JWT, Portielje JEA, van den Bos F.
Haas LEM, van Beusekom I, van Dijk D, Hamaker ME, Bakhshi-Raiez F, de Lange DW, de Keizer NF.
Medical decision making for older patients during multidisciplinary oncology team meetings.
Bolle S, Smets EMA, Hamaker ME, Loos EF, van Weert JCM.
J Geriatr Oncol. 2019 Jan;10(1):74-83. doi: 10.1016/j.jgo.2018.07.016. Epub 2018 Sep 11.
The effect of a geriatric evaluation on treatment decisions and outcome for older cancer patients - A systematic review.
Hamaker ME, Te Molder M, Thielen N, van Munster BC, Schiphorst AH, van Huis LH.
J Geriatr Oncol. 2018 Sep;9(5):430-440. doi: 10.1016/j.jgo.2018.03.014. Epub 2018 Apr 7.
Driessen EJM, Schulkes KJG, Dingemans AC, van Loon JGM, Hamaker ME, Aarts MJ, Janssen-Heijnen MLG.
Lung Cancer. 2018 Feb;116:55-61. doi: 10.1016/j.lungcan.2017.12.013. Epub 2017 Dec 20.
Update in geriatrics: What geriatric oncology can learn from general geriatric research.
Hamaker ME, Prins M, van Huis LH.
J Geriatr Oncol. 2018 Jul;9(4):393-397. doi: 10.1016/j.jgo.2018.01.005. Epub 2018 Feb 1.
Quality of life in elderly patients with an ostomy - a study from the population-based PROFILES registry.
Verweij NM, Bonhof CS, Schiphorst AHW, Maas HA, Mols F, Pronk A, Hamaker ME.
Colorectal Dis. 2018 Apr;20(4):O92-O102. doi: 10.1111/codi.13989.
Chemotherapy and healthcare utilisation near the end of life in patients with cancer.
Schulkes KJG, van Walree IC, van Elden LJR, van den Bos F, van Huis-Tanja L, Lammers JJ, Ten Bokkel Huinink D, Hamaker ME.
Eur J Cancer Care (Engl). 2018 Mar;27(2):e12796. doi: 10.1111/ecc.12796. Epub 2017 Nov 16.
Risk stratification for surgical outcomes in older colorectal cancer patients using ISAR-HP and G8 screening tools.
Souwer ETD, Verweij NM, van den Bos F, Bastiaannet E, Slangen RME, Steup WH, Hamaker ME, Portielje JEA.
J Geriatr Oncol. 2018 Mar;9(2):110-114. doi: 10.1016/j.jgo.2017.09.003. Epub 2017 Nov 10.
[Evidence based tailoring of cancer care for older patients].
Hamaker ME, van den Bos F.
Tijdschr Gerontol Geriatr. 2017 Dec;48(6):263-270. doi: 10.1007/s12439-017-0235-3. Dutch.
The impact of postoperative complications on health-related quality of life in older patients with rectal cancer; a prospective cohort study.
Couwenberg AM, de Beer FSA, Intven MPW, Burbach JPM, Smits AB, Consten ECJ, Schiphorst AHW, Wijffels NAT, de Roos MAJ, Hamaker ME, van Grevenstein WMU, Verkooijen HM.
J Geriatr Oncol. 2018 Mar;9(2):102-109. doi: 10.1016/j.jgo.2017.09.005. Epub 2017 Oct 10.
Multidisciplinary decision-making regarding chemotherapy for lung cancer patients-An age-based comparison.
Schulkes KJG, Hamaker ME, Lammers JJ, van Rens MTM, Geerts M, van Elden LJR.
Eur J Cancer Care (Engl). 2018 Jan;27(1). doi: 10.1111/ecc.12768. Epub 2017 Sep 21.
The effect of a geriatric evaluation on treatment decisions for older patients with colorectal cancer.
Verweij NM, Souwer ETD, Schiphorst AHW, Maas HA, Portielje JEA, Pronk A, van den Bos F, Hamaker ME.
Int J Colorectal Dis. 2017 Nov;32(11):1625-1629. doi: 10.1007/s00384-017-2883-8. Epub 2017 Sep 20.
Lung Cancer in the Oldest Old: A Nation-Wide Study in The Netherlands.
Schulkes KJG, Pouw CAM, Driessen EJM, van Elden LJR, van den Bos F, Janssen-Heijnen MLG, Lammers JJ, Hamaker ME.
Lung. 2017 Oct;195(5):627-634. doi: 10.1007/s00408-017-0026-1. Epub 2017 Jun 19.
Hamaker ME, Wildes TM, Rostoft S.
J Clin Oncol. 2017 Sep 1;35(25):2871-2874. doi: 10.1200/JCO.2017.72.8170. Epub 2017 Jun 19. No abstract available.
Controversial issues in the management of older adults with early breast cancer.
Mislang AR, Cheung KL, Hamaker ME, Kunkler I, Markopoulos C, Orecchia R, Brain E, Biganzoli L.
J Geriatr Oncol. 2017 Nov;8(6):397-402. doi: 10.1016/j.jgo.2017.05.004. Epub 2017 Jun 9. Review.
Corrigendum: A closer look at the trajectory of physical functioning in chronic hemodialysis.
Age Ageing. 2018 Mar 1;47(2):320. doi: 10.1093/ageing/afx040. No abstract available.
Schulkes KJG, Souwer ETD, van Elden LJR, Codrington H, van der Sar-van der Brugge S, Lammers JJ, Portielje JEA, van den Bos F, Hamaker ME.
Clin Lung Cancer. 2017 Nov;18(6):660-666.e1. doi: 10.1016/j.cllc.2017.02.006. Epub 2017 Mar 2.
The Effect of A Geriatric Assessment on Treatment Decisions for Patients with Lung Cancer.
Schulkes KJ, Souwer ET, Hamaker ME, Codrington H, van der Sar-van der Brugge S, Lammers JJ, Portielje JE, van Elden LJ, van den Bos F.
Lung. 2017 Apr;195(2):225-231. doi: 10.1007/s00408-017-9983-7. Epub 2017 Mar 9.
Selection of Patients in Ongoing Clinical Trials on Lung Cancer.
Schulkes KJ, Nguyen C, van den Bos F, van Elden LJ, Hamaker ME.
Lung. 2016 Dec;194(6):967-974. Epub 2016 Sep 20.
Management of chronic lymphocytic leukemia (CLL) in the elderly: a position paper from an international Society of Geriatric Oncology (SIOG) Task Force.
Stauder R, Eichhorst B, Hamaker ME, Kaplanov K, Morrison VA, Österborg A, Poddubnaya I, Woyach JA, Shanafelt T, Smolej L, Ysebaert L, Goede V.
Ann Oncol. 2017 Feb 1;28(2):218-227. doi: 10.1093/annonc/mdw547.
The impact of an ostomy on older colorectal cancer patients: a cross-sectional survey.
Verweij NM, Hamaker ME, Zimmerman DD, van Loon YT, van den Bos F, Pronk A, Borel Rinkes IH, Schiphorst AH.
Int J Colorectal Dis. 2017 Jan;32(1):89-94. doi: 10.1007/s00384-016-2665-8. Epub 2016 Oct 8.
Physical performance measures for predicting outcome in cancer patients: a systematic review.
Verweij NM, Schiphorst AH, Pronk A, van den Bos F, Hamaker ME.
Acta Oncol. 2016 Dec;55(12):1386-1391. Epub 2016 Oct 8. Review.
Evaluation and reporting of quality of life outcomes in phase III chemotherapy trials for poor prognosis malignancies.
Hamaker ME, Schulkes KJ, Ten Bokkel Huinink D, van Munster BC, van Huis LH, van den Bos F.
Qual Life Res. 2017 Jan;26(1):65-71. doi: 10.1007/s11136-016-1360-0. Epub 2016 Jul 5.
Relevance of a Geriatric Assessment for Elderly Patients With Lung Cancer-A Systematic Review.
Schulkes KJ, Hamaker ME, van den Bos F, van Elden LJ.
Clin Lung Cancer. 2016 Sep;17(5):341-349.e3. doi: 10.1016/j.cllc.2016.05.007. Epub 2016 Jun 2. Review.
Patient-Centered Outcome Measures in Lung Cancer Trials.
Schulkes KJ, Nguyen C, van den Bos F, Hamaker ME, van Elden LJ.
Lung. 2016 Aug;194(4):647-52. doi: 10.1007/s00408-016-9903-2. Epub 2016 Jun 10.
Clinical judgement and geriatric assessment for predicting prognosis and chemotherapy completion in older patients with a hematological malignancy.
Hamaker ME, Augschoell J, Stauder R.
Leuk Lymphoma. 2016 Nov;57(11):2560-7. doi: 10.3109/10428194.2016.1163345. Epub 2016 Apr 6.
Colorectal Cancer Resections in the Oldest Old Between 2011 and 2012 in The Netherlands.
Verweij NM, Schiphorst AH, Maas HA, Zimmerman DD, van den Bos F, Pronk A, Borel Rinkes IH, Hamaker ME.
Ann Surg Oncol. 2016 Jun;23(6):1875-82. doi: 10.1245/s10434-015-5085-z. Epub 2016 Jan 19.
Long-term Results of a Randomized Double-blinded Prospective Trial of a Lightweight (Ultrapro) Versus a Heavyweight Mesh (Prolene) in Laparoscopic Total Extraperitoneal Inguinal Hernia Repair (TULP-trial).
Burgmans JP, Voorbrood CE, Simmermacher RK, Schouten N, Smakman N, Clevers G, Davids PH, Verleisdonk EM, Hamaker ME, Lange JF, van Dalen T.
Ann Surg. 2016 May;263(5):862-6. doi: 10.1097/SLA.0000000000001579.
van Walree IC, van Tuyl SA, Hamaker ME.
Neth J Med. 2015 Jan;73(1):4-9. Review.
Geriatric consultation can aid in complex treatment decisions for elderly cancer patients.
Schiphorst AH, Ten Bokkel Huinink D, Breumelhof R, Burgmans JP, Pronk A, Hamaker ME.
Eur J Cancer Care (Engl). 2016 May;25(3):365-70. doi: 10.1111/ecc.12349. Epub 2015 Jul 24.
A national survey on the decision-making process of dialysis initiation in elderly patients.
van Loon IN, Boereboom FT, Bots ML, Verhaar MC, Hamaker ME.
Neth J Med. 2015 Jun;73(5):227-35.
Non-surgical complications after laparoscopic and open surgery for colorectal cancer - A systematic review of randomised controlled trials.
Schiphorst AH, Verweij NM, Pronk A, Borel Rinkes IH, Hamaker ME.
Eur J Surg Oncol. 2015 Sep;41(9):1118-27. doi: 10.1016/j.ejso.2015.04.007. Epub 2015 May 1. Review.
Multidisciplinary decision-making on chemotherapy for colorectal cancer: an age-based comparison.
Hamaker ME, van Rixtel B, Thunnissen P, Oberndorff AH, Smakman N, Ten Bokkel Huinink D.
J Geriatr Oncol. 2015 May;6(3):225-32. doi: 10.1016/j.jgo.2015.01.002. Epub 2015 Jan 24.
Assessing treatment effects in older breast cancer patients: systematic review of observational research methods.
de Glas NA, Kiderlen M, de Craen AJ, Hamaker ME, Portielje JE, van de Velde CJ, Liefers GJ, Bastiaannet E.
Cancer Treat Rev. 2015 Mar;41(3):254-61. doi: 10.1016/j.ctrv.2014.12.014. Epub 2015 Jan 10. Review.
Three-month results of the effect of Ultrapro or Prolene mesh on post-operative pain and well-being following endoscopic totally extraperitoneal hernia repair (TULP trial).
Burgmans JP, Voorbrood CE, Schouten N, Smakman N, Elias S, Clevers GJ, Davids PH, Verleisdonk EJ, Hamaker ME, Simmermacher RK, van Dalen T.
Surg Endosc. 2015 Nov;29(11):3171-8. doi: 10.1007/s00464-014-4049-x. Epub 2015 Jan 1.
Long-term changes in physical capacity after colorectal cancer treatment.
Hamaker ME, Prins MC, Schiphorst AH, van Tuyl SA, Pronk A, van den Bos F.
J Geriatr Oncol. 2015 Mar;6(2):153-64. doi: 10.1016/j.jgo.2014.10.001. Epub 2014 Nov 6. Review.
Representation of the elderly in trials of laparoscopic surgery for colorectal cancer.
Schiphorst AH, Pronk A, Borel Rinkes IH, Hamaker ME.
Colorectal Dis. 2014 Dec;16(12):976-83. doi: 10.1111/codi.12806.
Current palliative chemotherapy trials in the elderly neglect patient-centred outcome measures.
van Bekkum ML, van Munster BC, Thunnissen PL, Smorenburg CH, Hamaker ME.
J Geriatr Oncol. 2015 Jan;6(1):15-22. doi: 10.1016/j.jgo.2014.09.181. Epub 2014 Oct 3.


I've been told I'm not an easy person to buy a gift for. Given my obsession with beer (drinking it, sure, but also researching it, brewing it, chasing around town for it), it should be easy, right? Just buy me an interesting six-pack, I say. But apparently I've given folks the impression that I'm a bit particular, and they have a little trepidation about buying me beer. D'oh, foot shot.
To make amends, and to aid my fellow beer geeks, I'm here to help.
A new and growing trend is vintage beer. Yep, there are certain beers that can develop and improve (much like a fine wine) after a few years in the cellar. One of the best examples is barley wine, both English (like Avery Samael's Ale or Weyerbacher Blithering Idiot) and American (like Sierra Nevada Bigfoot or Smuttynose Barleywine Style Ale). While these ales pack a boozy punch when young, a year or two melds that heat into sweet notes of caramel, amaretto, and dried fruits like raisins and figs.
So this year when you're holiday shopping for the beer geek on your list, just pop into your favorite bottle shop and ask for a bomber (wine bottle–sized) of their finest barley wine. A note attached saying "This is to add to your beer cellar" is sure to impress.
Patrick Dawson is the author of Vintage Beer. Find more from Patrick on his website.


To celebrate the premiere of ELVIS, the world's first social slots game featuring The King of Rock 'n' Roll, Slotomania is giving away awesome bundles of Slotomania goodies to ten lucky ELVIS slots fans this Friday, November 1! This contest lasts for a limited-time only so Elvis fans upload those videos!
to hear your favorite songs from the King of Rock N' Roll!
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