The TRPV4 channel links calcium influx to DDX3X activity and viral infectivity

Ion channels are well placed to transduce environmental cues into signals used by cells to generate a wide range of responses, but little is known about their role in the regulation of RNA metabolism. Here we show that the TRPV4 cation channel binds the DEAD-box RNA helicase DDX3X and regulates its function. TRPV4-mediated Ca2+ influx releases DDX3X from the channel and drives DDX3X nuclear translocation, a process that involves calmodulin (CaM) and the CaM-dependent kinase II. Genetic depletion or pharmacological inhibition of TRPV4 diminishes DDX3X-dependent functions, including nuclear viral export and translation. Furthermore, TRPV4 mediates Ca2+ influx and nuclear accumulation of DDX3X in cells exposed to the Zika virus or the purified viral envelope protein. Consequently, targeting of TRPV4 reduces infectivity of dengue, hepatitis C and Zika viruses. Together, our results highlight the role of TRPV4 in the regulation of DDX3X-dependent control of RNA metabolism and viral infectivity

From Mouse To Human : Comparative Analysis Between Grey And White Matter By Synchrotron-Fourier Transformed Infrared Microspectroscopy

Fourier Transform Infrared microspectroscopy (μFTIR) is a very useful method to analyze the biochemical properties of biological samples in situ. Many diseases affecting the central nervous system (CNS) have been studied using this method, to elucidate alterations in lipid oxidation or protein aggregation, among others. In this work, we describe in detail the characteristics between grey matter (GM) and white matter (WM) areas of the human brain by μFTIR, and we compare them with the mouse brain (strain C57BL/6), the most used animal model in neurological disorders. Our results show a clear different infrared profile between brain areas in the lipid region of both species. After applying a second derivative in the data, we established a 1.5 threshold value for the lipid/protein ratio to discriminate between GM and WM areas in non-pathological conditions. Furthermore, we demonstrated intrinsic differences of lipids and proteins by cerebral area. Lipids from GM present higher C=CH, C=O and CH3 functional groups compared to WM in humans and mice. Regarding proteins, GM present lower Amide II amounts and higher intramolecular β-sheet structure amounts with respect to WM in both species. However, the presence of intermolecular β-sheet structures, which is related to β-aggregation, was only observed in the GM of some human individuals. The present study defines the relevant biochemical properties of non-pathological human and mouse brains by μFTIR as a benchmark for future studies involving CNS pathological samples

Transcriptional response to metal starvation in the emerging pathogen Mycoplasma genitalium is mediated by Fur-dependent and -independent regulatory pathways

Transition metals participate in numerous enzymatic reactions and they are essential for survival in all living organisms. For this reason, bacterial pathogens have evolved dedicated machineries to effectively compete with their hosts and scavenge metals at the site of infection. In this study, we investigated the mechanisms controlling metal acquisition in the emerging human pathogen Mycoplasma genitalium. We observed a robust transcriptional response to metal starvation, and many genes coding for predicted lipoproteins and ABC-transporters were significantly up-regulated. Transcriptional analysis of a mutant strain lacking a metalloregulator of the Fur family revealed the activation of a full operon encoding a putative metal transporter system and a gene coding for a Histidine-rich lipoprotein (Hrl). We recognized a conserved sequence with dyad symmetry within the promoter region of the Fur-regulated genes. Mutagenesis of the predicted Fur operator within the hrl promoter abrogated Fur- and metal-dependent expression of a reporter gene. Metal starvation still impelled a strong transcriptional response in the fur mutant, demonstrating the existence of Fur-independent regulatory pathways controlling metal homeostasis. Finally, analysis of metal accumulation in the wild-type strain and the fur mutant by ICP-MS revealed an important role of Fur in nickel acquisition

TRPV2: A Key Player in Myelination Disorders of the Central Nervous System

Transient potential receptor vanilloid 2 (TRPV2) is widely expressed through the nervous system and specifically found in neuronal subpopulations and some glial cells. TRPV2 is known to be sensitized by methionine oxidation, which results from inflammation. Here we aim to characterize the expression and regulation of TRPV2 in myelination pathologies, such as hypomyelination and demyelination. We validated the interaction between TRPV2 and its putative interactor Opalin, an oligodendrocyte marker, in mixed glial cultures under pro- and anti-inflammatory conditions. Then, we characterized TRPV2 time-course expression in experimental animal models of hypomyelination (jimpy mice) and de-/remyelination (cuprizone intoxication and experimental autoimmune encephalomyelitis (EAE)). TRPV2 showed upregulation associated with remyelination, inflammation in cuprizone and EAE models, and downregulation in hypomyelinated jimpy mice. TRPV2 expression was altered in human samples of multiple sclerosis (MS) patients. Additionally, we analyzed the expression of methionine sulfoxide reductase A (MSRA), an enzyme that reduces oxidated methionines in TRPV2, which we found increased in inflammatory conditions. These results suggest that TRPV2 may be a key player in myelination in accordance with the recapitulation hypothesis, and that it may become an interesting clinical target in the treatment of demyelination disorders

TRPV2 : a Key Player in Myelination Disorders of the Central Nervous System

Transient potential receptor vanilloid 2 (TRPV2) is widely expressed through the nervous system and specifically found in neuronal subpopulations and some glial cells. TRPV2 is known to be sensitized by methionine oxidation, which results from inflammation. Here we aim to characterize the expression and regulation of TRPV2 in myelination pathologies, such as hypomyelination and demyelination. We validated the interaction between TRPV2 and its putative interactor Opalin, an oligodendrocyte marker, in mixed glial cultures under pro- and anti-inflammatory conditions. Then, we characterized TRPV2 time-course expression in experimental animal models of hypomyelination (jimpy mice) and de-/remyelination (cuprizone intoxication and experimental autoimmune encephalomyelitis (EAE)). TRPV2 showed upregulation associated with remyelination, inflammation in cuprizone and EAE models, and downregulation in hypomyelinated jimpy mice. TRPV2 expression was altered in human samples of multiple sclerosis (MS) patients. Additionally, we analyzed the expression of methionine sulfoxide reductase A (MSRA), an enzyme that reduces oxidated methionines in TRPV2, which we found increased in inflammatory conditions. These results suggest that TRPV2 may be a key player in myelination in accordance with the recapitulation hypothesis, and that it may become an interesting clinical target in the treatment of demyelination disorders

Dynamic factors of bacteriorhodopsin : regulation key points in helices B, C and F /

Consultable des del TDXTítol obtingut de la portada digitalitzadaThe main objective of this work is the analysis of the structural and functional role of some amino acids in Bacteriorhodopsin. - Characterization of the motif Thr90-Pro91 in the centre of Helix C of Bacteriorhodopsin. Because Thr90 interacts with Asp115 through a hydrogen bond and with the retinal through hydrophobic interaction, the mutants T90V and D115A were taken into account. The following objectives were settled: Design and construct the Bacteriorhodopsin mutants P91A, T90A,T90V and D115A by site directed mutagenesis. Express the mutants in the purple membrane of Halobacterium salinarum. Analyze the role of Thr90 and Pro91 in the properties of the protein and in the proton pumping function in particular through the study of the mutants. Infer a role to the motif Thr90-Pro91 in Bacteriorhodopsin. - Analyze the role of the other two Prolines located in transmembrane helices in BR, and to extend this role to other Transmembrane Proteins. The subsequent objectives were proposed: Design and construct the Bacteriorhodopsin mutants P50A and P186A by site directed mutagenesis. Express the mutants in the purple membrane of Halobacterium salinarum. Characterize the role of Pro50, and Pro186 in Bacteriorhodopsin properties and proton pumping through the analysis of the mutants. Infer a role to Helix-embedded prolines of Bacteriorhodopsin in particular and to transmembrane helices of proteins in general

El canal iònic TRPV2 obre camí a teràpies més efectives per a la hipertensió

Investigadors de la UAB han dut a terme dos estudis reveladors sobre TRPV2, un canal iònic fonamental en diverses funcions cel·lulars, que l'assenyala com a possible nova diana terapèutica a l'hora de tractar la hipertensió. Han descobert els efectes dilatadors dels vasos sanguinis que provoca la seva activació i han identificat una molècula capaç d'activar-lo de manera més potent que els fàrmacs coneguts fins a la data.Investigadores de la UAB han llevado a cabo dos estudios reveladores sobre TRPV2, un canal iónico fundamental en varias funciones celulares, que lo señala como posible nueva diana terapéutica en la hora de tratar la hipertensión. Han descubierto los efectos dilatadores de los vasos sanguíneos que provoca su activación y han identificado una molécula capaz de activarlo de manera más potente que los fármacos conocidos hasta la fecha.Researchers at the UAB have carried out two revealing studies on TRPV2, a key ion channel in several cellular functions, which points to it as a possible new therapeutic target in the treatment of hypertension. They have discovered the vessel-dilating effects of its activation and have identified a molecule capable of activating it in a more potent way than the drugs known to date

Optogenetics comes of age: novel inhibitory light-gated anionic channels allow efficient silencing of neural function

This is the peer reviewed version of the following article: A. Peralvárez-Marín, P. Garriga, Optogenetics Comes of Age: Novel Inhibitory Light-Gated Anionic Channels Allow Efficient Silencing of Neural Function. ChemBioChem 2016, 17, 204-206, which has been published in final form at http://dx.doi.org/10.1002/cbic.201500608. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingOptogenetics, the developing field of research that uses light-switchable biochemical tools in a sophisticated technological approach to monitor or control neural function, is rapidly evolving with the discovery and development of novel microbial rhodopsins. Light-absorbing membrane proteins, as tools for brain research, are promoting new applications within the discipline of optogenetics. Light-gated rhodopsin ion channels with better intrinsic light sensitivity and improved resolution are needed to overcome some of the current limitations of existing molecules. The recent discovery of light-gated inhibitory anion channels opens new opportunities for studying physiological neural processes and, at the same time, represent a powerful approach for elucidating the mechanisms of neurological and mental disorders that could benefit from this approach.Peer Reviewe

A TRPV2 interactome-based signature for prognosis in glioblastoma patients

Proteomics aids to the discovery and expansion of protein-protein interaction networks, which are key to understand molecular mechanisms in physiology and physiopathology, but also to infer protein function in a guilt-by-association fashion. In this study we use a systematic protein-protein interaction membrane yeast two-hybrid method to expand the interactome of TRPV2, a cation channel related to nervous system development. After validation of the interactome in silico, we define a TRPV2-interactome signature combining proteomics with the available physio-pathological data in Disgenet to find interactome-disease associations, highlighting nervous system disorders and neoplasms. The TRPV2-interactome signature against available experimental data is capable of discriminating overall risk in glioblastoma multiforme prognosis, progression, recurrence, and chemotherapy resistance. Beyond the impact on glioblastoma physiopathology, this study shows that combining systematic proteomics with in silico methods and available experimental data is key to open new perspectives to define novel biomarkers for diagnosis, prognosis and therapeutics in disease

Cross interactions between Apolipoprotein E and amyloid proteins in neurodegenerative diseases

Three common Apolipoprotein E isoforms, ApoE2, ApoE3, and ApoE4, are key regulators of lipid homeostasis, among other functions. Apolipoprotein E can interact with amyloid proteins. The isoforms differ by one or two residues at positions 112 and 158, and possess distinct structural conformations and functions, leading to isoform-specific roles in amyloid-based neurodegenerative diseases. Over 30 different amyloid proteins have been found to share similar characteristics of structure and toxicity, suggesting a common interactome. The molecular and genetic interactions of ApoE with amyloid proteins have been extensively studied in neurodegenerative diseases, but have not yet been well connected and clarified. Here we summarize essential features of the interactions between ApoE and different amyloid proteins, identify gaps in the understanding of the interactome and propose the general interaction mechanism between ApoE isoforms and amyloid proteins. Perhaps more importantly, this review outlines what we can learn from the interactome of ApoE and amyloid proteins; that is the need to see both ApoE and amyloid proteins as a basis to understand neurodegenerative diseases