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Dutta, S.

Publications and source records attributed to Dutta, S..

At least 55 records · Page 3Linked to original sources

seekrflow: Towards end-to-end automated simulation pipeline with machine-learned force fields for accelerated drug-target kinetic and ther-modynamic predictions

Accurate prediction of drug-target binding and unbinding kinetics and thermodynamics is essential for guiding drug discovery and lead optimization. However, traditional atomistic simulations are often too computationally expensive to capture rare events that govern ligand (un)binding. Several enhanced sampling methods exist to overcome these limitations, but they require extensive manual intervention and introduce variability and artifacts in free energy and kinetic estimates that limit high-throughput scalability. The present work introduces seekrflow, an automated multiscale milestoning simulation pipeline that streamlines the entire workflow from a single receptor-ligand input structure to kinetic and thermodynamic predictions in a single step. This integrated approach minimizes manual intervention, reduces computational overhead, and enhances the reproducibility and accuracy of kinetic and thermodynamic predictions. The accuracy and efficiency of the pipeline is demonstrated on multiple receptor-ligand complexes, including inhibitors of heat shock protein 90, threonine-tyrosine kinase, and the trypsin protein, with predicted kinetic parameters closely matching experimental estimates. seekrflow establishes a new benchmark for automated and high-throughput physics-based predictions of kinetics and thermodynamics. O_FIG O_LINKSMALLFIG WIDTH=187 HEIGHT=200 SRC="FIGDIR/small/669965v2_ufig1.gif" ALT="Figure 1"> View larger version (74K): org.highwire.dtl.DTLVardef@c4da23org.highwire.dtl.DTLVardef@1cd386eorg.highwire.dtl.DTLVardef@33f50corg.highwire.dtl.DTLVardef@11d1f5a_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

Predicting statistics of gene translocation events: role of chromatin compaction and double-strand DNA break

How the 3D organization of chromatin affects gene translocation is an open question. By Monte Carlo simulation of translocation events in folded chromatin, we examine how the probability of translocation (Tij) is influenced by chromatin compaction and the occurrence of double-stranded DNA breaks (DSBs). Our results show that, beyond the two-segment contact probability, Tij depends on the overall compaction of the polymer and has a non-trivial contribution from multi-bead contacts and the probability of DSBs. We propose an empirical formula and provide analytical arguments for simple cases.

biophysics↗

Repeat Systemic Delivery of Cross-Neutralization Resistant Synthetic Vesiculoviruses Immunomodulates the Tumor Microenvironment

The clinical efficacy of systemic oncolytic virotherapy (OV) is constrained by the rapid development of neutralizing antibodies (nAbs), which prevent repeat systemic administration, a critical barrier to sustained anti-tumor immunity. Vesiculoviruses offer potent oncolytic and immunogenic potential. However, leveraging their serological diversity for repeat dosing remains unexplored. We generated a library of chimeric vesiculovirus vectors incorporating glycoproteins from less well characterized vesiculovirus species. We evaluated vector replication, infectivity, interferon (IFN) responses, and oncolysis in vitro, alongside assessments of neutralization resistance using patient sera, monoclonal antibodies, and in silico structural modeling. In vivo studies assessed tumor delivery, immune activation, and therapeutic efficacy following intravenous administration. The vesiculovirus library exhibited broad tumor infectivity, distinct IFN-stimulatory profiles, and variable oncolytic activity. Neutralization assays and computational modeling identified serological distinctness across vectors, driven by hypervariable glycoprotein epitopes, enabling evasion of cross-neutralizing antibodies. Tumor delivery and anti-tumor immunity were preserved despite humoral barriers. Incorporating tumor-associated antigens (TAAs) further amplified anti-tumor responses, even in the context of anti-viral memory. Sequential administration of distinct vesiculovirus vectors induced robust immune activation and improved survival in a B16-OVA-IFNAR-/- model. Our findings establish a glycoprotein-diverse vesiculovirus platform capable of overcoming humoral immunity, enabling repeat intravenous dosing and sustained engagement of the tumor microenvironment. This strategy advances the field of oncolytic virotherapy by addressing a major translational barrier and lays the groundwork for future clinical studies integrating multi-vector, multi-dose immunovirotherapy with immune checkpoint blockade. One Sentence SummaryA glycoprotein-engineered vesiculovirus platform circumvents neutralizing antibodies, enabling repeat intravenous dosing and sustained anti-tumor immunity in preclinical models.

molecular biology↗

Membrane curvature during membrane rupture and formation of pentagonal pyramidal superassemblies by a pore-forming toxin, Vibrio cholerae Cytolysin, using single particle cryo-EM

In this cryo-electron microscopy study, we provide mechanistic insights into how an archetypical {beta}-barrel pore-forming toxin ({beta}-PFT), Vibrio cholerae Cytolysin (VCC), ruptures the membrane lipid bilayer by inducing membrane curvature. We demonstrate how VCC oligomers cluster together and drastically increase local membrane curvature, thereby causing membrane blebbing. In addition, we also show how these PFTs after rupturing the host membrane tend to form symmetric super-molecular assemblies to stabilize their hydrophobic transmembrane rim domains. We further provide another example of membrane rupture with gamma hemolysin, a Staphylococcal bicomponent {beta}-PFT. These insights will usher new studies on membrane curvature due to protein crowding and broaden our mechanistic understanding of how this largest class of bacterial protein toxins induce host cellular death.

biophysics↗

Psychrophilic and cryophilic bacterial copiotrophs from a Trans-Himalayan lake-desert ecosystem as biogeothermometers of warming, mitigators of perturbation, and candidates for biodegradation

A Trans-Himalayan lake-desert ecosystem was explored for the low-to-high temperature adaptations of native copiotrophic psychrophiles that have the potentials for rendering substantive carbon remineralization under natural and/or anthropogenically influenced conditions of high organic matter delivery to the environment. Overall 27 species, classified across 15 genera of Actinomycetota, Bacillota, Bacteroidota, and Pseudomonadota, were isolated from the brackish-water and sediment-surface of Tso Moriri (a massive lacustrine body on the Changthang plateau that remains frozen for approximately one third of the year), and the fine talus covering a lake-side rocky mountain. In Luria broth, all the isolates grew at 4{degrees}C and 15{degrees}C; 13 of them grew, while 14 retained 19-99% cells in metabolically-active state, at -10{degrees}C; 23, 11, and none grew at 28{degrees}C, 37{degrees}C, and 42{degrees}C respectively. A Cryobacterium was most heat-susceptible, whereas some -10{degrees}C-growing Arthrobacter, Microbacterium, Paenarthrobacter, Pseudomonas and Streptomyces were most warming-resilient, among the present isolates. Catabolizing different simple/complex organic compounds, all isolates accomplished low/moderate/high growths at 4{degrees}C; 20 performed low growths at -10{degrees}C. Taxonomy/phylogeny did not determine the isolates growth/survival across the temperature-range tested. Lake-water and rock-dust isolates had the widest, while lake-sediment-dwellers had the narrowest, temperature-window for growth/survival. Rock-dust and lake-water isolates had more genes for low and high temperature adaptations, compared to the lake-sediment isolates. In co-cultures, most actinobacterial isolates inhibited the growth of mesophilic bacteria from warmer ecosystems, plus non-actinobacteria and actinobacteria from native/adjoining habitats. The data hold implications for biodegradation in cold/frigid territories, negative feedback control/reversal of warming, and microbiome protection from infiltration amidst climate change. IMPORTANCEPhylogenetically diverse, cold-adapted copiotrophic bacteria were retrieved from a Trans-Himalayan lake-desert ecosystem, and tested for chemoorganoheterotrophic growth at temperatures between -10{degrees}C and 42{degrees}C. Albeit growth dwindled at [≥]28{degrees}C, most of the isolates thrived on simple as well as complex organic substances under freezing condition, which makes them prospective constituents of biodegradation reactors suitable for high-altitude/latitude deployment. In the natural habitats of the psychrophilic isolates, cessation of organotrophic activities at elevated temperatures would stop simple fatty acids and CO2 production, which in turn would preempt methanogenesis, undo greenhouse effect, and reverse environmental thawing (usher cooling). Such negative feedback control of homeostasis is fraught with the danger of microbiome takeover by thermally-better-adapted foreign organisms. Consequently, ecosystem preservation rests on the native microfloras ability to resist external invasion. At 28{degrees}C, majority of the actinobacterial isolates inhibited bacteria from discrete higher-temperature ecosystems; they can, therefore, be viewed as the defenders of the cold/frigid ecosystem.

microbiology↗

Molecular insights into inhibitor action on a key bacterial metabolic enzyme Cystathionine β-Synthase

Tuberculosis (TB) remains a major global health threat, with Mycobacterium tuberculosis (Mtb) infecting nearly a quarter of the global population. Drug-resistant TB and HIV-TB co- infections emphasize the need for novel therapeutic approaches targeting essential metabolic pathways. Here, we investigated Mtb cystathionine {beta}-synthase (MtbCBS), a PLP-dependent enzyme critical for sulfur metabolism and redox regulation, owing its potential as a therapeutic target. We present the first high-resolution cryo-EM structure of MtbCBS bound to aminooxyacetic acid (AOAA), and employed molecular dynamics (MD) simulations, quantum mechanics/molecular mechanics (QM/MM) calculations, and comparative inhibition studies to reveal the molecular basis and determinants governing irreversible PLP-enzyme inhibition. Our Cryo-EM structural analysis revealed two highly conserved active-site residues, T75 and Q147, critically stabilizing the inhibitor complex. Through molecular mimic studies, we demonstrated the precise structural factors and electronic features critical for inhibition efficiency. These findings provide the first mechanistic rationale for PLP enzyme inhibition and offer a generalizable framework for designing covalent inhibitors targeting PLP-dependent enzymes implicated in infectious diseases, cancer, and neurological disorders. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=115 SRC="FIGDIR/small/662948v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@195c7c7org.highwire.dtl.DTLVardef@6ee0c8org.highwire.dtl.DTLVardef@1679dfborg.highwire.dtl.DTLVardef@1b4e000_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical Abstract.C_FLOATNO Proposed mechanism of MtbCBS inhibition by AOAA. Proposed mechanism of action of AOAA illustrated through a graphical representation. The cartoon shows the domains of MtbCBS. Tetrameric structure of MtbCBS with active site highlighted (in red dashes). Enlarged view indicating the PLP-AOAA blocked intermediate interacting with residue Q147. Reaction scheme depicting the previous missing understanding of active site residue role in -elimination. Schematic representation of AOAA inhibition mechanism in the catalytic cycle of MtbCBS. Reactions were drawn using ChemDraw. The proposed scheme highlights that AOAA (highlighted Red) binding is stabilized by nearby residues Q147 and T75, leading to the formation of PLP-AOAA covalent adduct, and substrates (highlighted green) were incapable of reverting the suicidal inhibition. The directionality and reversibility were mentioned for each step. C_FIG

biophysics↗

The 5-HT1A receptor antagonist WAY-100635 maleate reprograms metabolism to promote RGC differentiation and regeneration in retino-visual centers

Metabolic collapse of retinal ganglion cells (RGCs) onsets glaucoma, yet no approved drug directly protects these neurons. Through a live-cell mitochondrial screen in human stem-cell-derived hRGCs we uncovered WAY-100635 (WAY), a clinically tested 5-HT1A antagonist, as a systemic neuroprotectant. WAY triggers a reversible cyclic-AMP surge that activates PGC-1-driven reversible mitochondrial biogenesis and suppresses apoptosis. In glaucoma associated OPTNE50K hRGCs, WAY restores mitochondrial fitness, dampens excitotoxicity, and reprograms metabolism toward aerobic glycolysis, while in progenitors WAY boosts mitochondrial cristae maturation, oxidative phosphorylation, and cell-cycle exit to accelerate RGC specification. Daily intraperitoneal dosing preserves RGC bodies, neural activity, promotes axon regeneration into the optic nerve and vision centers after optic-nerve crush, as well as shows RGC protection and maintenance of visual acuity in chronic ocular hypertension glaucoma. As the non-invasive neuroprotective therapy with a human safety profile, WAY addresses a critical gap in glaucoma care and potentially for other mitochondrial optic neuropathies. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=187 SRC="FIGDIR/small/659983v1_ufig1.gif" ALT="Figure 1"> View larger version (65K): org.highwire.dtl.DTLVardef@131ff3eorg.highwire.dtl.DTLVardef@16c4e6borg.highwire.dtl.DTLVardef@190724eorg.highwire.dtl.DTLVardef@4067e4_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

Tau-seed interactome analysis reveals distinct functional signatures in Alzheimer's disease across model systems.

Tau aggregates propagate through the brain in a prion-like manner in Alzheimers disease (AD) and other tauopathies, but the molecular identity and functional partners of the seeding-competent Tau species remain poorly defined. Here, we present an unbiased proteomic profiling of a high-molecular-weight (HMW) Tau-seed isolated from AD patient brains. We contrast this interactome with that of a biochemically similar, seeding-incompetent HMW-Tau species from age-matched healthy controls. Despite comprising less than 5% of total Tau in the brain, Tau-seed associates with a distinct set of proteins enriched in synaptic, mitochondrial, and vesicle-trafficking functions. Cross-species functional screening in Drosophila and mouse models identifies interactors that modulate Tau toxicity and seeding. Spatially resolved analysis of postmortem AD brains reveals heterogenous co-deposition of these proteins with Tau aggregates, suggesting functionally distinct Tau-seed complexes. Together, this dataset provides a framework for understanding selective Tau-seed toxicity and identifies candidate regulators of Tau propagation with therapeutic potential.

neuroscience↗

Spatio-temporal chromosomal arrangements by late-replicating heterochromatin

Fungal centromeres are clustered near microtubule organizing centers to help adopt the Rabl chromosomal organization. The role of centromere clustering in driving large-scale changes in structural and functional chromatin assembly remains unclear. Here, using Hi-C and super-resolution microscopy, we show that cell cycle-dependent centromere declustering and clustering states in Cryptococcus neoformans drive global changes in the 3D genome architecture. Centromeres and telomeres are scattered around the nuclear periphery at interphaseG1, and this arrangement constrains the inter-arm interactions within a chromosome, providing a unique interphaseG1 chromosome organization. Moreover, centromeres and telomeres are organized as compartments, segregating them from active euchromatic regions. Polymer modeling reveals that the transition from the unclustered to clustered centromere state during the cell cycle involves changes from a globular to an elongated chromosome architecture. Strikingly, while clustered centromeres replicate early in most yeasts, C. neoformans centromeres replicate late in S-phase, hinting a possible link between centromere clustering dynamics and CEN DNA replication timing. Overall, our study uncovers several unique organizational principles governing the dynamic genome architecture in an evolutionarily diverged basidiomycete yeast. SignificanceChromosomes occupy the nuclear space in many ways. Primary chromosomal arrangements are such that centromere regions of different chromosomes either form a cluster, as in yeasts, or are scattered around the nuclear periphery, more common in metazoans. Exceptionally, centromeres show cell cycle stage-specific clustering in the basidiomycete fungus Cryptococcus neoformans. We show that the spatial positioning and the refractory nature of centromeres and telomeres shape the arrangement and large-scale organization of chromosomes in C. neoformans. Metazoan-like late-replicating centromeres in C. neoformans possibly favor the unclustered/scattered centromere state in S-phase, not commonly found in fungi. Our results not only highlight the remarkable genome plasticity of C. neoformans but also raise the possibility that centromere replication timing determines genome organization principles.

genomics↗

eIF3d and eIF3e mediate selective translational control of hypoxia that can be inhibited by novel small molecules

Exposure to hypoxia is linked to increased cellular plasticity and enhanced metastasis; effects which are primarily attributed to the transcriptional activation of large gene programs downstream of hypoxia inducible factors (HIFs). However, translational effects in hypoxia, that likely precede transcriptional effects, have remained largely unexplored. Using ribosome-profiling, we uncovered a selective translational response in acute hypoxia that is eIF3d/eIF3e-dependent and controls downstream hypoxic responses including HIF1a accumulation and cellular invasion. We further demonstrated that eIF3e copy number and an eIF3e-expression signature are associated with worsened outcomes for breast cancer patients. Finally, we identified a class of novel small molecules that target eIF3e specifically, reducing the translational response to hypoxia and to ER stress, another stressor that is dependent on eIF3d/eIF3e-mediated translation. Our data uncover critical functions for eIF3d/eIF3e in the hypoxic response and identify a potential means to inhibit stress-induced translation, and potentially plasticity and metastasis, mediated by eIF3e.

cancer biology↗

RNAse-free manufacture of Venezuelan Equine Encephalitis Virus (VEEV) plasmid DNA vaccine

The long shelf-life and stability of DNA makes this platform highly attractive for low-cost, rapid delivery of pandemic response vaccines. Protocols utilized for clinical grade plasmid manufacture by contract development and manufacturing organizations are not readily accessible to academic and public research laboratories engaged in early-phase plasmid vaccine development. We present here the framework for DNA manufacturing using 3L-scale fermentation, anion-exchange chromatography and tangential flow filtration (TFF) leading to RNAase-free manufacture of plasmid DNA. The Venezuelan Equine Encephalitis Virus vaccine plasmid pWRG/VEEV, encoding the glycoprotein (E)3, E2, 6K and E1 genes was used as the prototype for this process development. The current effort yielded >95% pure and >80% supercoiled pWRG/VEEV plasmid preparations at 50-g wet cell weight scale. These data showed feasibility of manufacturing, highly pure pWRG/VEEV plasmid DNA using a cGMP compliant manufacturing process. Distribution StatementApproved for public release: distribution is unlimited

biochemistry↗

A novel mechanism of morphogenetic transition in Schizosaccharomyces pombe dependent on the MAPK Spc1 and the transcription factor Atf1 associated with sensing of optimal growth environment

Fission yeast Schizosaccharomyces pombe are rod shaped eukaryotic cells that grow by tip elongation and divide medially by formation of cell wall septum. The coordination between cell length and cell cycle phase transitions in this simple eukaryote makes it an excellent model system for studying morphogenetic events associated with both intrinsic and extrinsic disturbances in cell cycle regulation. Cell cycle progression in S. pombe is dependent on the coordinated functions of two bZIP family transcription factors Atf1 and Pcr1. In an attempt to understand this coordination, we stumbled upon the startling observation that overexpression of Atf1 in cells lacking Pcr1 led to drastic morphogenetic alteration whereby the cells became hyper elongated. In this report we present the evidences of dependence of this phenotype on metabolic status of the cell. We also show that the phenotype is dependent on the activity of the Mitogen Activated Protein Kinase, Spc1 and that it is associated with the global gene expression alterations of cells resulting from the perturbed balance of Atf1 and Pcr1 activities. We found that change in the carbon source, alterations in iron concentration and the redox environment of the cell can affect the extent of morphogenesis, to the extent of even abolishing it at times. Our results also indicate that this phenotype has a strong association with maintenance of optimum growth conditions of the cell. Taken together, our observations reveal a completely novel mechanism of morphogenetic transition in fission yeast involving the MAPK Spc1 and its downstream effector molecule Atf1, which can be tuned by the cells metabolic environment.

microbiology↗

Immunogenicity and Structural Features of a Stabilized Clade-C HIV-1 Env Derived from a Pediatric Elite-neutralizer

The envelope (Env) glycoprotein derived from circulating viruses in elite-neutralizers (who naturally develop broadly neutralizing antibodies (bNAbs)), serves as potential template for HIV-1 vaccine design. Herein, we report the structure and immunogenicity of soluble clade-C HIV-1 Env trimer (330) derived from a pediatric elite-neutralizer (AIIMS_330). Using SOSIP, NFL and ferritin-nanoparticle (NP) platforms, we engineered immunogens that preserved native-like Env conformation, exhibited high thermostability and nanomolar affinity for diverse bNAbs, with minimal reactivity to non-neutralizing antibodies. Cryo-EM structure solved at 5 [A] resolution of 330-SOSIP trimer-autologous bNAb 44m complex revealed interactions at GDIR motif, N332 supersite along with additional contacts at E293, K337, K446 and glycans N326, N442, N448, as compared to our previously reported BG505-44m structure. Rabbit immunizations with soluble and NP-displayed formats elicited autologous, and heterologous neutralization of tier-1 clade-C viruses. Herein we define a structurally resolved HIV-1 clade C Env that supports multivalent vaccine strategies and provides mechanistic insights toward rational HIV-1 immunogen design.

immunology↗

Cryo-EM reveals the structural heterogeneity and conformational flexibility of multidrug efflux pumps MdtB and MdtF

RND efflux pumps are a major cause of multidrug resistance in bacteria, particularly in Gram-negative bacteria. They are complex molecular machines forming tripartite assemblies that actively pump out a wide range of antimicrobial agents, including antibiotics, biocides and host defence molecules. However, the presence of multiple RND pumps with overlapping functions in a single bacterium raises questions about their individual functional relevance. In this study, we determined the Cryo-EM structures of two distinct HAE-RND pumps from E.coli., MdtB and MdtF. MdtF is a unique class of RND pump whose expression is regulated by oxygen availability and is crucial for the survival of E.coli in anaerobic growth conditions. Surprisingly, homotrimeric MdtB, previously reported to be inactive, exhibited activity in our experiments. Cryo-EM structure determination of MdtF at 2.8 [A] resolution revealed the flexible transmembrane domain with significant conformational changes in the core helixes, leading to the closure of the central pore. While the MdtB structure adopts a resting state, MdtF displays structural dynamics in the presence of DDM. The apo structures of both pumps unveil novel conformational states of HAE-RND efflux transporters. Our findings highlight significant structural and functional divergence among closely related HAE-RND proteins. Despite 71% sequence similarity and phylogenetic proximity to AcrB, the structure of MdtF differs from the solved AcrB structures. In contrast, the MdtB structure exhibits greater resemblance to AcrB, regardless of 32% sequence similarity. Furthermore, our structural analysis provides insights into drug-binding sites and the transport mechanism of these important transporters.

biophysics↗

Gut Microbe-Derived N-Acyl Serinol Lipids Shape Host Postprandial Metabolic Homeostasis

Although strong evidence links the gut microbiome to metabolic disease, the mechanisms linking microbiota to hormonal and metabolic responses to food are not well understood. After a meal, gut bacteria produce a wide array of small molecule, protein, and lipid metabolites originating from bacterial sources. Annotating physiological function to select gut microbe-derived metabolites is critical to understanding diet-microbe-host interactions, and to developing microbiome-inspired therapies to improve human health. Here, we have investigated the role of a poorly annotated class of gut microbiome-derived lipids called N-acyl amides in postprandial metabolic physiology. Here we show both bacterial overproduction and provision of exogenous N-acyl amides reorganize host hormone-driven metabolic transition after a meal. Moreover, N-acyl amides exert broad effects on the meal- and circadian-related reorganization of gene expression, metabolic hormones, and gut microbiome composition. Collectively, these results demonstrate that microbiota-derived N-acyl amides play a physiologic role in postprandial metabolic homeostasis in the host.

physiology↗

Gut Microbe-Derived Trimethylamine Shapes Circadian Rhythms Through the Host Receptor TAAR5

Elevated levels of the gut microbe-derived metabolite trimethylamine N-oxide (TMAO) are associated with cardiometabolic disease risk. However, the mechanism(s) linking TMAO production to human disease are incompletely understood. Initiation of the metaorganismal TMAO pathway begins when dietary choline and related metabolites are converted to trimethylamine (TMA) by gut bacteria. Gut microbe-derived TMA can then be further oxidized by host flavin-containing monooxygenases to generate TMAO. Previously, we showed that drugs lowering both TMA and TMAO protect mice against obesity via rewiring of host circadian rhythms. Although most mechanistic studies in the literature have focused on the metabolic end product TMAO, here we have instead tested whether the primary metabolite TMA alters host metabolic homeostasis and circadian rhythms via trace amine-associated receptor 5 (TAAR5). Remarkably, mice lacking the host TMA receptor (Taar5-/-) have altered circadian rhythms in gene expression, metabolic hormones, gut microbiome composition, and diverse behaviors. Also, mice genetically lacking bacterial TMA production or host TMA oxidation have altered circadian rhythms. These results provide new insights into diet-microbe-host interactions relevant to cardiometabolic disease, and implicate gut bacterial production of TMA and the host receptor that senses TMA (TAAR5) in the physiologic regulation of circadian rhythms in mice. HIGHLIGHTSO_LIMice lacking the host TMA receptor (Taar5-/-) have altered circadian rhythms. C_LIO_LITaar5-/- mice have altered innate behaviors in a time of day dependent manner. C_LIO_LIThe normal circadian oscillations in the gut microbiome are dysregulated in Taar5-/- mice. C_LIO_LIGenetic deletion of bacterial TMA production or host TMA oxidation shapes circadian rhythms. C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=137 HEIGHT=200 SRC="FIGDIR/small/647082v2_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@1608forg.highwire.dtl.DTLVardef@6a809aorg.highwire.dtl.DTLVardef@2131f7org.highwire.dtl.DTLVardef@1575559_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

Tubulin hyperacetylation drives HMGB1 nuclear exit via the ROS-PARP1 axis leading to rotenone-induced G2/M Arrest

Rotenone, a lipophilic pesticide, is strongly linked to dopaminergic neuronal loss in Parkinsons disease (PD), primarily through mitochondrial complex I inhibition. While rotenone induces G2/M arrest in dividing cells, the underlying molecular events remain unclear. We identify HMGB1 as a key player in this process. HMGB1, known for its roles in genomic integrity and inflammation, exits the nucleus during rotenone-induced G2/M arrest, whereas its nuclear retention protects against mitotic DNA damage. We further reveal that tubulin hyperacetylation precedes HMGB1 nuclear release. Notably, reducing tubulin acetyltransferase lowers mitochondrial ROS (mtROS), preventing HMGB1 nuclear exit and mitotic DNA damage. Additionally, inhibiting PARP1 hyperactivation with PJ34 blocks HMGB1 exit and prevents G2/M arrest. These findings suggest that ROS-induced DNA damage elevates PARP1 activity, promoting HMGB1 nuclear exit and interfering with DNA repair. This tubulin acetylation/mtROS/HMGB1 axis may underlie rotenone-induced neurotoxicity, contributing to dopaminergic neuron vulnerability in PD and offering potential neuroprotective targets.

cell biology↗

Development of a thermostable and broadly neutralizing pan-sarbecovirus vaccine candidate

Zoonotic spillover of sarbecoviruses to humans resulted in theSARS-CoV-1 outbreak in 2003 and the current COVID-19 pandemic caused by SARS-CoV-2. In both cases, the viral spike protein (S) is the principal target of neutralising antibodies that prevent infection. Within spike, the immunodominant receptor-binding domain (RBD) is the primary target of neutralising antibodies in COVID-19 convalescent sera and vaccine recipients. We have constructed stabilized RBD derivatives of different sarbecoviruses: SARS-CoV-1 (Clade 1a), WIV-1 (Clade 1a), RaTG13 (Clade 1b), RmYN02 (Clade 2) and BtKY72 (Clade 3). Stabilization enhanced yield by an 3-23-fold. The RBD derivatives were conformationally intact as assayed by binding to multiple broadly neutralizing antibodies. The stabilized RBDs show significant enhancement in apparent Tm, exhibit resistance to a 2-hour incubation at temperatures up to 60 in PBS in contrast to corresponding WT RBDs, and show prolonged stability of over 15 days at 37 after lyophilization. In mice immunizations, both stabilization and trimerization significantly enhanced elicited neutralization titers by [~]100 fold. The stabilized RBD cocktail elicited high neutralizing titers against both homologous and heterologous pseudoviruses. The immunogenicity of the vaccine formulation was assessed in both naive and SARS-CoV-2 pre-immunized mice, revealing an absence of immune imprinting, thus indicating its suitability for use in future sarbecovirus-origin epidemics or pandemics. Author summaryThe COVID-19 pandemic was caused by the sarbecovirus SARS-CoV-2. Phylogenetically, sarbecoviruses are divided into four clades: Clade 1a, Clade 1b, Clade 2 and Clade 3 and within these clades, are many other sarbecovirus strains with pandemic or epidemic potential. It is therefore important to develop a broadly protective, pan-sarbecovirus vaccine formulation that can be cheaply and rapidly produced. While mRNA vaccine formulations are efficacious, they have stringent low temperature storage requirements and there is limited manufacturing expertise in low and middle income countries for this modality. Neutralizing antibodies are important for protection and in the case of SARS-CoV-2 are primarily directed against the Receptor Binding Domain (RBD) of the surface spike protein. In this study, we have designed and developed an adjuvanted, protein subunit, pan sarbecovirus vaccine formulation using stabilized RBD derivatives from diverse sarbecoviruses as immunogens. We demonstrate that the stabilized RBD derivatives have considerably enhanced yield and thermal stability relative to corresponding WT proteins and that the formulation remains stable for up to two weeks at 37{degrees}C. The formulation was found to be highly immunogenic in both naive and pre-immunized mice, eliciting neutralizing titers well above the known protective threshold, indicating its suitability for use in future sarbecovirus-origin epidemics or pandemics.

immunology↗