Biology subjects

Saha, S.

Publications and source records attributed to Saha, S..

At least 127 records · Page 7Linked to original sources

bioRxiv2023

Regulation of apico-basolateral trafficking polarity of homologous Copper-ATPases ATP7A and ATP7B

We suggest a model of apico-basolateral sorting in polarized epithelia using homologous Cu-ATPases as membrane cargoes. In polarized epithelia, upon copper treatment, homologous copper-ATPases ATP7A and ATP7B traffic from trans-Golgi network (TGN) to basolateral and apical membranes respectively. We characterized sorting pathways of Cu-ATPases between TGN and plasma-membrane and identified the machinery involved. ATP7A and ATP7B reside on distinct domains of TGN and in high copper, ATP7A traffics directly to basolateral membrane, whereas ATP7B traverses common-recycling, apical-sorting and apical-recycling endosomes en-route to apical membrane. Mass-spectrometry identified regulatory partners of ATP7A and ATP7B that include Adaptor Protein-1 complex. Upon knocking-out pan-AP-1, sorting of both copper-ATPases are disrupted. ATP7A loses polarity and localizes on both apical and basolateral surfaces in high copper. Contrastingly, ATP7B loses TGN-retention but retains apical polarity that becomes copper-independent. Using isoform-specific knockouts, we found that AP-1A provides directionality and TGN-retention for both Cu-ATPases, whereas, AP-1B governs polarized trafficking of ATP7B solely. Trafficking phenotypes of Wilson disease-causing ATP7B mutants that disrupts putative ATP7B-AP1 interaction further substantiates the role of AP-1 in apical sorting of ATP7B. Summary statementThe Adapter Protein-1 (AP-1) isoforms AP-1A and AP-1B governs the apico-basolateral trafficking polarities of the homologous Copper-ATPases, ATP7A and ATP7B at the trans-Golgi network.

cell biology↗

bioRxiv2023

Gardnerella vaginolysin potentiates glycan molecular mimicry by Neisseria gonorrhoeae

Bacterial vaginosis (BV) is a condition of the vaginal microbiome in which there are lower levels of "healthy" Lactobacillus species and an outgrowth of diverse anaerobic bacteria. BV is associated with increased risk of infection by the bacterium Neisseria gonorrhoeae - the causative agent of gonorrhea. Here we test if one known facet of BV - the presence of bacterial cytolysins - leads to the mobilization of specific intracellular contents that aid in gonococcal virulence. We cloned and expressed recombinant vaginolysin (VLY), a cytolysin produced by the BV-associated bacterium Gardnerella, verifying that it liberates the contents of red blood cells and cervical epithelial (HeLa) cells while vector control preparations made in parallel did not. We tested if VLY mediates a well-known virulence mechanism of gonococcus - the molecular mimicry of host glycans. To evade host immunity, N. gonorrhoeae caps its surface lipooligosaccharide (LOS) with 2-3-linked sialic acid. To do this, gonococci must scavenge an intermediate metabolite made and used inside host cells. Flow-cytometry based lectin-binding assays showed that, compared to controls, gonococci exposed to vaginolysin-liberated contents of HeLa cells displayed greater sialic acid capping of their LOS. This higher level of bacterial sialylation was accompanied by increased binding of the complement regulatory protein Factor H, and greater resistance to complement attack. Together these results suggest that cytolytic activities present during BV may enhance the ability of N. gonorrhoeae to capture intracellular metabolites and evade host immunity via glycan molecular mimicry.

microbiology↗

bioRxiv2023

More than just an Eagle Killer: The freshwater cyanobacterium Aetokthonos hydrillicola produces highly toxic dolastatin derivatives

Cyanobacteria are infamous producers of toxins. While the toxic potential of planktic cyanobacterial blooms is well documented, the ecosystem level effects of toxigenic benthic and epiphytic cyanobacteria are an understudied threat. The freshwater epiphytic cyanobacterium Aetokthonos hydrillicola has recently been shown to produce the "eagle killer" neurotoxin aetokthonotoxin causing the fatal neurological disease Vacuolar Myelinopathy. The disease affects a wide array of wildlife in the southeastern United States, most notably waterfowl and birds of prey, including the bald eagle. In an assay for cytotoxicity, we found the crude extract of the cyanobacterium to be much more potent than pure aetokthonotoxin, prompting further investigation. Here, we describe the isolation and structure elucidation of the aetokthonostatins, linear peptides belonging to the dolastatin compound family, featuring a unique modification of the C-terminal phenylalanine derived moiety. Using immunofluorescence microscopy and molecular modeling, we confirmed that aetokthonostatin acts as a potent tubulin binder. We also show that aetokthonostatin inhibits reproduction of the nematode C. elegans, resulting in increased population lethality of the combined action of the two toxins produced by A. hydrillicola. Bioinformatic analysis revealed the aetokthonostatin biosynthetic gene cluster encoding a non-ribosomal peptide synthe-tase/polyketide synthase accompanied by a unique tailoring machinery. The biosynthetic activity of a specific N-terminal methyltransferase was confirmed by in vitro biochemical studies, establishing a mechanistic link between the gene cluster and its product. Significance StatementCyanotoxins have adverse effects on ecosystems. Our understanding of their potential risk has recently been expanded by the discovery of aetokthonotoxin, produced by the cyanobacterium Aetokthonos hydrillicola growing on invasive plants. Via trophic transfer, it acts as a neurotoxin causing mortality in animals including top predators like Bald Eagles. Closer examination of A. hydrillicola revealed that it also produces highly toxic dolastatin derivatives. A. hydrillicola is the first cultured cyanobacterium producing dolastatin derivatives, allowing us to uncover biosynthetic gene clusters of this compound family. In contrast to all other known dolastatin-producers, which are marine cyanobacteria, A. hydrillicola thrives in freshwater reservoirs, making it a potential threat also for human health. Monitoring of the cyanobacterium and its toxins is strongly recommended.

microbiology↗

bioRxiv2023

Functional connectivity in northern swamp deer (Rucervus duvaucelii duvaucelii) population across a fragmented, human-dominated landscape along Gangetic Plains of north India: Implications for conservation in non-protected areas

The Indian subcontinent has witnessed disproportionate declines in large mammalian herbivore communities. The northern swamp deer (Rucervus duvaucelii duvaucelii) exemplifies the conservation challenges of typical non-protected area species, where apart from distribution status other ecological information is limited for the upper Gangetic basin population. We combined elements of radio-telemetry and conservation genetics to evaluate dispersal patterns, population connectivity and assess genetic variation and inbreeding status of this population living across a highly human-dominated area. We genetically identified 266 unique swamp deer and further analyses revealed presence of two spatially-admixed genetic lineages with moderate heterozygosity (Ho=0.51, SD= 0.10) and low inbreeding (FIS=0.133) status. Multi- disciplinary evidence suggests that the small, isolated grassland patches between Jhilmil Jheel Conservation Reserve (JJCR) and Hastinapur Wildlife Sanctuary (HWLS) are highly preferred by swamp deer during migrations and are genetically connected. The southern part of the area in HWLS showed early signatures of genetic discontinuity that require immediate conservation attention. We hypothesized that the human settlement history of this landscape, river dynamics and species ability to negotiate various pressures and disperse has helped to maintain such connectivity. While these signatures are encouraging for this small, isolated cervid population, careful management interventions are required to ensure the integrity and functionality of this landscape. We recommend a scientifically robust population estimation approach across this landscape and a multi-stakeholder-driven strategies to augment population and habitat recovery, plantation and riverscape management to ensure long-term survival of this species.

ecology↗

bioRxiv2023

Neuromolecular interactions guiding homeostatic mechanisms underlying healthy ageing: A view from computational microscope

Ageing brain is associated with a slow drift in structural network properties over the lifespan accompanied by reorganization in neuromolecular interactions giving rise to changes in global functional markers. What are the guiding principles of the homeostatic mechanisms that maintain the desired performance of functional neural circuits and preserve brain health during healthy ageing? We hypothesize that an ageing brain alters two primary neurotransmitters, glutamate and{gamma} -aminobutyric acid (GABA), responsible for excitation-inhibition regulation, concomitant with anatomical demyelination to preserve critical neural dynamics that are necessary to uphold optimal network performance. Thus, often observed re-organized functional connectivity with age by several investigations is a byproduct of this adaptive process. We demonstrate that the adaptive mechanism is driven by the tuning of glutamate and GABA concentration over a very slow time scale (lifespan) that can be estimated by tracking criticality from co-ordinated neural dynamics at a resting state via a biophysically driven computational framework, introduced as a computational microscope. We validate several empirical observations and model predictions across three independent aging cohorts using this computational microscope. One of the key mechanisms we discover is the reduction in local glutamate levels employed by brain regions to maintain a homeostatic balance with aging. This is further supported by the invariance of measures of global functional integration during the healthy ageing process.

neuroscience↗

bioRxiv2023

Community mixing selects for predation resistance in lab-evolved communities of bacterial prey and social predator Myxococcus xanthus

Population mixing, and transmission modes strongly influence social interactions. However, the impact of repeated mixing on the evolutionary dynamics of microbial predator-prey interactions remains underexplored1,2. Hence, we conducted a laboratory evolution experiment with bacterial predator-prey communities under two transfer regimens: repeated mixing (horizontal transfer) versus no mixing (vertical transfer). For this, Myxococcus xanthus served as the generalist predator3,4 and Escherichia coli as prey. We show that prey populations from vertical regimen were less resistant to predation than the ones from horizontal regimen. This was because prey isolates in the vertical treatment showed varying resistance levels relative to ancestors, while those in the horizontal treatment demonstrated less variation. Moreover, analysis of prey populations over evolutionary time revealed that the populations from horizontal treatment showed increasing levels of resistance to predation over time, whereas the ones from vertical treatment did not show similar trend. The differences in the outcomes of the two treatments was because the variants better at intraspecies competition, can only be maintained in the vertical treatment, whereas in horizontal treatment the benefits of superior intraspecies competitive fitness are nullified because of population mixing, as predicted by mathematical modeling approach. These predictions were empirically confirmed. Moreover, contrary to our expectations, predatory efficiency of evolved M. xanthus isolates was either the same or lesser than the ancestor. Together, we demonstrate that mixing affects the evolution of prey bacteria but has little effect on the hunting ability of the social predator M. xanthus.

evolutionary biology↗

bioRxiv2023

Europe PMC Annotated Full-text Corpus for Gene/Proteins, Diseases and Organisms

Named entity recognition (NER) is a widely used text-mining and natural language processing (NLP) sub-task. In recent years, deep learning methods have superseded traditional dictionary, and rule-based NER approaches. A high-quality dataset is essential to take full advantage of the recent deep learning advancements. While several gold standard corpora for biomedical entities in abstracts exist, only a few are based on full-text research articles. The Europe PMC literature database routinely annotates Gene/Proteins, Diseases and Organisms entities; to transition this pipeline from a dictionary-based to a machine learning-based approach, we have developed a human-annotated full-text corpus for these entities comprising 300 full-text open access research articles. Over 72,000 mentions of biomedical concepts have been identified within approximately 114,000 sentences. This article describes the corpus and details how to access and reuse this open community resource.

bioinformatics↗

bioRxiv2023

Structural insights into agonist-binding and activation of the human complement C3a receptor

The complement cascade is an integral part of innate immunity, and it plays a crucial role in our bodys innate immune response including combating microbial infections. Activation of the complement cascade results in the generation of multiple peptide fragments, of which complement C3a and C5a are potent anaphylatoxins. The complement C3a binds and activates a G protein-coupled receptor (GPCR) known as C3aR while C5a activates two distinct receptors namely C5aR1 and C5aR2. Our current understanding of complement peptide recognition by their corresponding receptors is limited primarily to biochemical studies, and direct structural visualization of ligand-receptor complexes is still elusive. Here, we present structural snapshots of C3aR in complex with heterotrimeric G-proteins, with the receptor in ligand-free state, activated by full-length complement C3a, and a peptide agonist EP54, derived based on the carboxyl-terminal sequence of C5a. A comprehensive analysis of these structures uncovers the critical residues involved in C3a-C3aR interaction, and also provides molecular insights to rationally design carboxyl-terminal fragments of C3a and C5a to act as potent agonists of the receptor. Surprisingly, a comparison of C3a-C3aR structure with C5a-C5aR1 structure reveals diagonally opposite placement of these two complement peptides on their respective receptors, which helps explain the subtype selectivity of these complement peptides. Finally, taking lead from the structural insights, we also identify EP141, a peptide derived from the carboxyl-terminus of C3a, as a G-protein-biased agonist at C3aR. Taken together, our study illuminates the structural mechanism of complement C3a recognition by C3aR, and it also offers the first structural template for designing novel C3aR ligands with therapeutic potential for inflammatory disorders.

biochemistry↗

bioRxiv2023

Toxic metal uptake by oyster mushrooms grown in sugarcane bagasse

Fungiculture or Mushroom Cultivation is rapidly expanding throughout the world. It is further catalyzed by its high nutritional value and increased market demand. Additionally, the method of cultivation does not require much space and the per unit production is very high compared to other crops. Bagasse is the byproduct left after extracting the juice from sugarcane. It has been speculated that bagasse can be an excellent substrate due to its high carbohydrate and mineral content (Hoa et al., 2015). In the experiment spawns of Oyster Mushroom were inoculated in bagasse collected from industries. Remarkable growth of mushrooms in short period of time was observed. However, the metal toxicity being our primary concern in this experiment, AAS (Atomic Absorption Spectrometry) Test was used to detect the heavy metal ion concentrations in both the bagasse and the fruiting bodies of mushrooms. The concentrations of metals calculated are as follows, in bagasse (mg/kg): Cadmium - 0.015, Arsenic - 8.56, Copper-12.47, Chromium-9.17, Mercury - less than 0.01, and in mushroom (mg/kg): Cd - 0.022, As - 10.12, Cu - 14.29, Cr - 7.59, Hg - less than 0.01. These results indicated biomagnification of metal ion concentration in the mushrooms up taken from bagasse. These metals, in such high concentrations are lethal and causes many diseases in humans and other animals. Hence, from this experiment it can be deduced, that though bagasse is an excellent substrate for mushroom cultivation, the toxicity of metal ions present in it in such high concentrations overshadow the earlier benefits of bagasse as a good substrate. However, it has been proposed that if such metals are removed or their concentrations are lowered then the earlier mentioned benefits of bagasse are restored.

ecology↗

bioRxiv2023

Signaling in microbial communities with open boundaries

Microbial communities such as swarms or biofilms often form at the interfaces of solid substrates and open fluid flows. At the same time, in laboratory environments these communities are commonly studied using microfluidic devices with media flows and open boundaries. Extracellular signaling within these communities is therefore subject to different constraints than signaling within classic, closed-boundary systems such as developing embryos or tissues, yet is understudied by comparison. Here, we use mathematical modeling to show how advective-diffusive boundary flows and population geometry impact cell-cell signaling in monolayer microbial communities. We reveal conditions where the intercellular signaling lengthscale depends solely on the population geometry and not on diffusion or degradation, as commonly expected. We further demonstrate that diffusive coupling with the boundary flow can produce signal gradients within an isogenic population, even when there is no flow within the population. We use our theory to provide new insights into the signaling mechanisms of published experimental results, and we make several experimentally verifiable predictions. Our research highlights the importance of carefully evaluating boundary dynamics and environmental geometry when modeling microbial cell-cell signaling and informs the study of cell behaviors in both natural and synthetic systems. O_TEXTBOXSIGNIFICANCEMicrobial communities in natural environments and microfluidic devices are often exposed to open boundaries and flows, but models used to characterize diffusive signaling in such systems often ignore how device geometry, boundary conditions, and media flow influence signaling behavior. We demonstrate how the effective signaling capacity of these communities can be shaped by population geometry and advective-diffusive boundary flow in quasi-2D environments. Our approach provides a general framework to understand and control advection-reaction-diffusion systems--and their interactions with cellular signaling networks--in both natural and synthetic environments. C_TEXTBOX

biophysics↗

bioRxiv2023

Structural insights into ligand-recognition, activation, and signaling-bias at the complement C5a receptor, C5aR1

Activation of the complement cascade is a critical part of our innate immune response against invading pathogens, and it operates in a concerted fashion with the antibodies and phagocytic cells towards the clearance of pathogens. The complement peptide C5a, generated during the activation of complement cascade, is a potent inflammatory molecule, and increased levels of C5a are implicated in multiple inflammatory disorders including the advanced stages of COVID-19 pathophysiology. The proximal step in C5a-mediated cellular and physiological responses is its interaction with two different seven transmembrane receptors (7TMRs) known as C5aR1 and C5aR2. Despite a large body of functional data on C5a-C5aR1 interaction, direct visualization of their interaction at high-resolution is still lacking, and it represents a significant knowledge gap in our current understanding of complement receptor activation and signaling. Here, we present cryo-EM structures of C5aR1 activated by its natural agonist C5a, and a G-protein-biased synthetic peptide ligand C5apep, in complex with heterotrimeric G-proteins. The C5a-C5aR1 structure reveals the ligand binding interface involving the N-terminus and extracellular loops of the receptor, and we observe that C5a exhibits a significant conformational change upon its interaction with the receptor compared to the basal conformation. On the other hand, the structural details of C5apep-C5aR1 complex provide a molecular basis to rationalize the ability of peptides, designed based on the carboxyl-terminus sequence of C5a, to act as potent agonists of the receptor, and also the mechanism underlying their biased agonism. In addition, these structural snapshots also reveal activation-associated conformational changes in C5aR1 including outward movement of TM6 and a dramatic rotation of helix 8, and the interaction interface for G-protein-coupling. In summary, this study provides previously lacking molecular basis for the complement C5a recognition and activation of C5aR1, and it should facilitate structure-based discovery of novel lead molecules to target C5aR1 in inflammatory disorders.

biophysics↗

bioRxiv2022

Kinesin family motors modify transcription mediated by ERR1 using a conserved nuclear receptor box motif

Kinesin family motors are microtubule (MT)-stimulated ATPases known best as transporters of cellular cargoes through the cytoplasm, regulators of MT dynamics, organizers of the mitotic spindle, and for insuring equal division of DNA during mitosis. Several kinesins have also been shown to regulate transcription by interacting with transcriptional cofactors and regulators, nuclear receptors, or with specific promotor elements on DNA. We previously showed that an LxxLL nuclear receptor box motif in the kinesin-2 family motor KIF17 mediates binding to the orphan nuclear receptor estrogen related receptor alpha (ERR1) and is responsible for the suppression of ERR1-dependent transcription by KIF17. Analysis of all kinesin family proteins revealed that multiple kinesins contain this LxxLL motif, raising the question as to whether additional kinesins motors contribute to regulation of ERR1. In this study, we interrogated the effects of multiple kinesins with LxxLL motifs on ERR1-mediated transcription. We demonstrate that the kinesin-3 motor KIF1B contains two LxxLL motifs, one of which binds to ERR1. In addition, we show that expression of a KIF1B fragment containing this LxxLL motif inhibits ERR1-dependent transcription by regulating nuclear entry of ERR1. We also provide evidence that the effects of expressing the KIF1B-LxxLL fragment on ERR1 activity are mediated by a mechanism distinct from that of KIF17. Because LxxLL domains are found in many kinesins, our data suggest an expanded role for kinesins in nuclear receptor mediated transcriptional regulation.

cell biology↗

bioRxiv2022

An integrated Bayesian framework for multi-omics prediction and classification

With the growing commonality of multi-omics datasets, there is now increasing evidence that integrated omics profiles lead to the more efficient discovery of clinically actionable biomarkers that enable better disease outcome prediction and patient stratification. Several methods exist to perform host phenotype prediction from crosssectional, single-omics data modalities but decentralized frameworks that jointly analyze multiple time-dependent omics data to highlight the integrative and dynamic impact of repeatedly measured biomarkers are currently limited. In this article, we propose a novel Bayesian ensemble method to consolidate prediction by combining information across several longitudinal and cross-sectional omics data layers. Unlike existing frequentist paradigms, our approach enables uncertainty quantification in prediction as well as interval estimation for a variety of quantities of interest based on posterior summaries. We apply our method to four published multi-omics datasets and demonstrate that it recapitulates known biology in addition to providing novel insights while also outperforming existing methods in estimation, prediction, and uncertainty quantification. Our open-source software is publicly available at https://github.com/himelmallick/IntegratedLearner.

bioinformatics↗

bioRxiv2022

IMPA1 dependent regulation of plasma membrane phosphatidylinositol 4,5-bisphosphate turnover and calcium signalling by lithium

Lithium (Li) is a widely used as a mood stabilizer in the clinical management of Bipolar Affective Disorder (BPAD). However, the molecular targets of Li in neural cells that underpin its therapeutic effect remain unresolved. Inositol monophosphatase (IMPA1), is an enzyme involved in the resynthesis of phosphatidylinositol 4,5-bisphosphate (PIP2) following receptor-activated phospholipase C (PLC) signalling. In vitro, Li inhibits IMPA1, but the relevance of this inhibition within neural cells remains unknown. Here we report that in human cells, treatment with therapeutically relevant concentrations of Li reduces receptor activated calcium release from intracellular stores and delays the resynthesis of PIP2 following receptor activated PLC signalling. Both these effects of Li are abrogated in cells where IMPA1 has been deleted. We also observed that in human forebrain cortical neurons, treatment with Li results in reduced neuronal excitability as well as reduced calcium signals following receptor activated PLC signalling. Following Li treatment of human forebrain cortical neurons, transcriptome analyses reveal downregulation of multiple components of the glutamate receptor signalling system. Glutamate is a key excitatory neurotransmitter in the human brain and thus our findings provide an insight into the mechanisms underlying the dampening of neuronal excitability following Li treatment. Collectively, our findings suggest that Li inhibits receptor activated PLC signalling leading to an altered transcriptional response and reduced neuronal excitability.

neuroscience↗

bioRxiv2022

Structural snapshots uncover a lock-and-key type conserved activation mechanism of β-arrestins by GPCRs

Agonist-induced phosphorylation of G protein-coupled receptors (GPCRs) is a key determinant for the binding and activation of multifunctional regulatory proteins known as {beta}-arrestins ({beta}arrs). Although the primary sequence and phosphorylation pattern of GPCRs are poorly conserved, the downstream functional responses mediated by {beta}arrs such as receptor desensitization, endocytosis and signaling are broadly applicable across GPCRs. A conserved principle of {beta}arr activation, if any, upon their interaction with different GPCRs harboring divergent phosphorylation patterns remains to be visualized, and it represents a major knowledge gap in our current understanding of GPCR signaling and regulatory paradigms. Here, we present four structural snapshots of activated {beta}arrs, in complex with distinct phosphorylation patterns derived from the carboxyl-terminus of three different GPCRs, determined using cryogenic-electron microscopy (cryo-EM). These structures of activated {beta}arrs elucidate a "lock-and-key" type conserved mechanism of {beta}arr activation wherein a P-X-P-P phosphorylation pattern in GPCRs interacts with a spatially organized K-K-R-R-K-K sequence in the N-domain of {beta}arrs. Interestingly, the P-X-P-P pattern simultaneously engages multiple structural elements in {beta}arrs responsible for maintaining the basal conformation, and thereby, leads to efficient {beta}arr activation. The conserved nature of this lock-and-key mechanism is further illustrated by a comprehensive sequence analysis of the human GPCRome, and demonstrated in cellular context with targeted mutagenesis including "loss-of-function" and "gain-of-function" experiments with respect to {beta}arr activation measured by an intrabody-based conformational sensor. Taken together, our findings uncover previously lacking structural insights, which explain the ability of distinct GPCRs to activate {beta}arrs through a common mechanism, and a key missing link in the conceptual framework of GPCR-{beta}arr interaction and resulting functional outcomes.

biochemistry↗

bioRxiv2022

Hepatitis C virus induces HuR relocalization by coordinating PKC-δ and AMPK- function

Host protein HuR translocation from nucleus to cytoplasm following infection is crucial for the life cycle of several RNA viruses including hepatitis C virus (HCV), a major causative agent of hepatocellular carcinoma. HuR assists the assembly of replication-complex on the viral-3'UTR, and its depletion hampers viral replication. Although cytoplasmic HuR is crucial for HCV replication, little is known about how the virus orchestrates the mobilization of HuR into the cytoplasm from the nucleus. We show that two viral proteins, NS3 and NS5A, act co-ordinately to alter the equilibrium of the nucleo-cytoplasmic movement of HuR. NS3 activates protein kinase C (PKC)-{delta}, which in-turn phosphorylates HuR on S318 residue, triggering its export to the cytoplasm. NS5A inactivates AMP-activated kinase (AMPK) resulting in diminished nuclear import of HuR through blockade of AMPK-mediated phosphorylation and acetylation of importin-1. Cytoplasmic retention or entry of HuR can be reversed by an AMPK activator or a PKC-{delta} inhibitor. Our findings suggest that efforts should be made to develop inhibitors of PKC-{delta} and AMPK, either separately or in combination, to inhibit HCV infection. Author summaryHepatitis C virus is a major human pathogen, which exploits cellular machinery for its propagation in liver cells. The cytoplasmic availability of cellular components is crucial for their direct influence on processes involving the viral RNA, which lacks any nuclear history. Our results establish the involvement of viral proteins, NS3 and NS5A in achieving increased cytoplasmic abundance of a host factor HuR, an RNA binding protein (RBP) critical for HCV replication. This is achieved via direct post-translational modification of HuR and indirect regulation of its nuclear carrier by coercing two host kinases, PKC-{delta} and AMPK-. RBPs are emerging as novel targetable candidates for gene regulation. Similar studies with other RBPs and targeting protein modifications, in place of whole protein knockdown, could usher in a revolutionary strategy to neutralize emerging RNA virus-based diseases, while preserving their cellular functions.

microbiology↗

bioRxiv2022

Selective Androgen Receptor Modulator Microparticle Formulation Reverses Muscle Hyperalgesia in Mouse Model of Widespread Muscle Pain

Currently, there is a need for the generation of non-opioid analgesics for treating chronic pain. Preclinical and clinical studies demonstrate the analgesic effects of testosterone. However, treatment with testosterone is not feasible due to adverse effects. Selective androgen receptor modulators (SARMs) were developed to overcome these limitations by minimizing activation of androgenic side effects. First, we demonstrate SARM administration alleviates widespread muscle pain in male and female mice. We then developed a SARM-loaded PLGA microparticle formulation that reverses widespread muscle pain in two injections. In vitro and in vivo release kinetics demonstrate the microparticle formulation had sustained SARM release for 4 weeks. Antagonism of androgen receptors blocked the analgesic effects of the SARM microparticles. SARM treatment had no effect on cardiac or liver enzymes, cardiac histology, and did not produce rewarding behavior. These studies demonstrate SARM microparticles as a potential therapeutic for chronic muscle pain. One Sentence SummaryA selective androgen receptor modulator microparticle formulation alleviates widespread muscle pain in male and female mice while being non-toxic.

neuroscience↗