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Biology subjects

Kumar, P.

Publications and source records attributed to Kumar, P..

At least 19 recordsLinked to original sources

AlphaGenome informed machine learning for pathogenicity prediction of germline mutations

Accurate interpretation of germline variants remains a central challenge in clinical genomics. Existing in silico pathogenicity predictors often provide incomplete coverage or restricted to missense variants from the coding region, leaving the variants from splice sites, -UTR, and intronic regions under-scored. We present AGVarPred, a gradient-boosted classifier designed to predict the pathogenicity of germline mutants, with a broad consequence-class coverage across SNVs and indels. Here, the population allele frequency from gnomAD, functional consequence annotations from Ensembl VEP, and cell-type-specific functional genomic scores from the AlphaGenome platform were integrated to develop the classifier. Using a gene-level split of 134,002 high-confidence ClinVar variants across 9,222 genes, AGVarPred achieved an AUC-ROC of 0.9753 (95% CI 0.9731-0.9775) and a AUC-PR of 0.9606 on 12,385 scored internal test variants. A paired DeLong analysis showed that the full model significantly outperformed an allele-frequency-plus-VEP model ({Delta}AUC = 0.1539, 95% CI 0.1489-0.1589; p < 1 x 10-300), supporting a substantial incremental contribution from AlphaGenome-derived features. Performance remained strong when restricted to SNVs (AUC-ROC 0.9558) and was also high for indels (AUC-ROC 0.9532). On five external benchmarks, AUC-ROCs ranged from 0.528 on a functional-assay-derived benchmark to 0.977 on a clinically curated deafness database, reflecting its dependence on benchmark composition and label source. A separate analysis of the VIP Database, whose pathogenic labels are ClinVar-derived, showed consistent performance (AUC-ROC of 0.892) in held-out genes. AGVarPred scored 100% of evaluated variants in the external benchmarks, whereas AlphaMissense and REVEL covered only small fractions of non-missense variants. Model interpretation indicated that gnomAD allele frequency was the dominant individual predictor; the 111 AlphaGenome features provided complementary functional signal, with splicing and chromatin assays contributing to the largest share of the AlphaGenome SHAP mass. A web-based interface for AGVarPred is available at https://pankaj357.github.io/AGVarPred/ to facilitate the submission of normalized GRCh38 germline variants and retrieval of pathogenicity predictions using the frozen AGVarPred model.

bioinformatics↗

Structural Insights into the Expanded Substrate Scope of a Cysteine-Dependent Hydrolase from Rhodococcus opacus for Polyethylene, Polypropylene, and Polystyrene Biodegradation

Microplastic pollution from homopolymers such as polypropylene (PP), polystyrene (PS), and polyethylene (PE) poses growing health and environmental concerns, highlighting the need for robust polymer-degrading biocatalysts. We previously identified a naturally occurring cysteine-dependent hydrolase (CsdH) from Rhodococcus opacus, featuring a unique Cys160-Lys127-Asp39 catalytic triad and providing a novel mechanism for polyethylene terephthalate (PET) degradation. In this study, we have determined crystal structures of CsdH in complex with PP, PS, PE, and styrene and demonstrated the potential of the enzyme to directly degrade these homopolymers into their respective low molecular weight degradation products using LC-MS. Structural analysis reveals that the enzyme retains a conserved principal access tunnel while undergoing subtle substrate-dependent changes to accommodate different substrates. The enzyme exhibited broad plastic degradation activity with the highest weight loss observed for PE, followed by PP and PS. SEM analysis reveals surface roughness, cracks and grooves, confirming polymer degradation. Further, these results corroborate through FTIR and TGA analysis. These findings establish a strong foundation for enzyme engineering and aim at developing efficient microplastic degradation.

biophysics↗

Cytokine-induced nuclear translocation of STAT1 via a non-transferable NLS

The targeting function of nuclear localization signals (NLSs) is generally considered independent of a protein's native sequence or fold and is readily transferable to heterologous cargos. Contrary to this paradigm, rapid nuclear translocation of phosphorylated STAT1 (pSTAT1) following cytokine stimulation requires importin {beta}, Ran-GTP, and the importin 5 isoform, which recognizes a non-transferable NLS. Here, we present cryo-EM structures of pSTAT1 bound to importin 5, revealing an asymmetric 2:1 complex that diverges from canonical NLS-mediated cargo recognition. Importin 5 occupies the DNA-binding groove of the pSTAT1 dimer, with a single STAT1 N-terminal domain positioning the C-terminal Armadillo repeats 9-10 (S1B domain) orthogonal to the DNA-binding interface. This interface is also targeted by the Ebola virus protein VP24, an antagonist of interferon signaling. We further show that Ran-GTP alone is insufficient to trigger nuclear release of pSTAT1, which additionally requires the exportin CAS. A cryo-EM reconstruction of the CAS-Ran-GTP-5 complex, supported by in vitro competition assays, demonstrates that CAS and pSTAT1 are mutually exclusive ligands for importin 5. Together, these findings define the molecular choreography of cytokine-induced STAT1 nuclear translocation and release, establishing a general paradigm for STAT family signaling.

biochemistry↗

Whole-Genome Metagenomics Insights Revealed a Uranium Bio-remediating Cross-Domain Microbiome in the Dhala Impact Structure, India

Meteorite impact structures on earth represent unique terrestrial analogues of extreme planetary environments where fractured lithologies, hydrothermal alteration, elevated concentrations of radionuclides, and prolonged water-rock interactions create ecological niches for specialized microbial communities. The Palaeoproterozoic Dhala impact structure in north-central India is characterized by uranium-bearing impactites and possesses a very high concentration of Uranium (up to 99.5 ppm) that makes it a unique natural laboratory to investigate microbial adaptation to radioactive and metal-rich geological environments. In addition, the Dhala structure harbors specialized radiotoxic hydrothermal mineral phases such as coffinite and pitchblende, which show a globally distinct and biologically unexplored niche. The present investigation is the first in-depth, whole-genome metagenomic study of soil and water samples of uranium-rich sites from the Dhala structure, exploring the whole microbial community (Bacteria, Archaea, Eukaryotes, and Viruses) up to the species level present in the samples. The cross-domain metagenomics analysis identified a highly unique and resilient microbiome that consists of bacteria, archaea, eukaryotes, and viruses, coevolved under prolonged radiological and multiple metal stress. Functional metagenomic analysis revealed numerous metabolic adaptations responsible for their survival, homeostasis, and biomineralization in situ. The deep sequencing method further enabled the identification of 58 functional genes directly involved in uranium bioremediation. Furthermore, this study revealed important pathways for radionuclide reduction, cellular efflux, and biotransformation. Novel findings of the present study point out the in-depth evolutionary relations of biosphere-geosphere interaction within an ancient hypervelocity impact-generated ecosystem. In a nutshell, the Dhala extremophiles with novel genetic makeup present an untapped and promising reservoir for the development of eco-friendly, next-generation microbial bioremediation strategies to efficiently tackle the global anthropogenic contamination of uranium and the challenges of nuclear waste management. Thus, the present study establishes Dhala structure as an unparalleled site for environmental geomicrobiology, microbial evolution, and astrobiology.

genomics↗

IKK2/β mediated phosphorylation of transcription factor Ets2 at site(s) distal to DNA binding domain negatively modulates its DNA binding activity

Transcription factor Ets2 coalesce with the NF-{kappa}B pathway to regulate gene expression in specific signaling contexts. IKK2/{beta}-mediated phosphorylation events critically regulate the NF-{kappa}B pathway. However, any link between Ets2 and IKK2 remains elusive. Here we report Ets2 as a direct substrate of IKK2. In-vitro kinase assays using deletion constructs, high resolution MS-MS and site directed mutagenesis identified S295 as a prominent phosphorylation site distal to the DNA binding domain, substitution of which to phosphor-mimetic Glutamate triggers further phosphorylation of Ets2. MD simulations clearly indicate conformational constriction of the otherwise disordered N-terminal region and inhibition of DNA binding activity upon phosphorylation, which was further confirmed by Electrophoretic mobility shift assays. Our results uncover a phosphoregulatory connection between Ets2 and IKK2.

biochemistry↗

UPLC-ESI-MS based lipidomics revealed novel biomarkers in insulin receptor knockdown induced type 2 diabetes model of Drosophila

Type 2 diabetes (T2D) is a prevalent metabolic disorder affecting millions worldwide, characterized by insulin resistance and impaired glucose homeostasis. While mammalian models are widely used, Drosophila melanogaster provides a powerful alternative due to its conserved insulin signaling pathways, genetic tractability, and suitability for high throughput studies. In addition to glucose dysregulation, lipid metabolism plays a crucial role in T2D pathophysiology, as alterations in lipid composition contribute to insulin resistance and metabolic dysfunction. Lipidomic studies have emerged as an essential approach to identify metabolic signatures and potential biomarkers for disease progression and therapeutic targeting. In this study, T2D like model was established by inducing insulin resistance through knockdown of the insulin receptor in brain insulin-producing cells using the dilp2-Gal4>UAS-InRRNAi system. This genetic manipulation resulted in significant metabolic dysregulation, including elevated glucose, trehalose, and triacylglyceride levels, along with increased oxidative stress indicators. Additionally, mRNA expression analysis of key insulin signaling components, including insulin receptor substrate 1, dilp2, dilp3, dilp5, and phosphorylated Akt, further validated the model. To further investigate metabolic alterations, Lipid profiling was performed using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) in non targeted LC-MS-based metabolomics approach to identify lipid biomarkers associated with T2D. Multivariate statistical analyses, including PCA and PLS-DA, revealed distinct lipid signatures between wild-type and T2D flies. Notably, specific phosphatidylglycerol species PG 34:0, PG 34:4, PA 38:3, PIP 38:1, PIP2 38:6, and LPS 24:0 demonstrated an area under the curve (AUC) of 1, indicating their strong reliability as lipid biomarkers for T2D diagnosis.

biochemistry↗

Structural Insights and Inhibitor Discovery for Kyasanur Forest Disease Virus NS5 Methyltransferase

Kyasanur Forest Disease Virus (KFDV) NS5 methyltransferase (MTase) protein is the essential enzyme that is involved in the cap methylation of viral RNA, viral replication, and immune evasion, and therefore it is an important protein of interest for antiviral research and drug design. In the present work, we successfully resolved the three-dimensional crystal structures of KFDV NS5 MTase co-crystallised with SAH and GTP at resolutions of 2.2 [A] and 2.6 [A], respectively. In previous studies, HC (Herbacetin) and CAPE (Caffeic acid phenethyl ester) have shown inhibitory activity against SAM-dependent viral MTase. To evaluate the inhibitory potential of HC and CAPE against KFDV NS5 MTase, we have performed isothermal titration calorimetry (ITC) and tryptophan fluorescence spectroscopy (TFS) to validate protein interaction with target compounds. MTase inhibition assay was performed using capillary electrophoresis (CE) assays. Additionally, fluorescence polarisation (FP) confirmed RNA binding inhibition by CAPE and HC. Together, these experiments suggest that HC and CAPE are promising inhibitors against KFDV NS5 MTase and could potentially act as lead compounds to design broad-spectrum anti-Orthoflavivirus drugs.

molecular biology↗

Inflammatory proteolysis generates pathogenic APOL1 fragments with distinct intracellular toxicities in podocytes derived from children with HIV associated nephropathy

APOL1 risk variants are the strongest genetic determinants of HIV-associated nephropathy (HIVAN), yet the mechanisms linking inflammation to APOL1-mediated podocyte injury remain poorly understood because authentic patient-derived human disease models are lacking. Using urine-derived podocytes established from children with HIVAN and endogenous APOL1 reporter cell lines derived from these cells, we identified a previously unrecognized pathway of inflammatory, cathepsin-dependent APOL1 proteolysis. Endogenous APOL1 cleavage was detected in patient-derived podocytes, whereas reporter cell lines enabled the identification and functional characterization of N-terminal and C-terminal APOL1 fragments with distinct intracellular localization and pathogenic functions. The nuclear N-terminal fragment activated inflammatory transcriptional programs and promoted podocyte injury, whereas the membrane-associated C-terminal fragment mediated membrane toxicity and remained susceptible to pharmacologic inhibition by inaxaplin. Cathepsin S directly cleaved APOL1 in vitro, linking inflammatory signaling to APOL1 fragmentation. These findings identify inflammatory APOL1 proteolysis as a mechanism that partitions APOL1 toxicity into distinct pathogenic programs and nominate APOL1 processing as a therapeutic target for HIV-associated and other APOL1-mediated kidney diseases.

cell biology↗

Targeting Tumor-derived Sphingosine Kinase 2 Unleashes Antitumor Immunity and Improves Survival of Mice with Group 3 Medulloblastoma

Group 3 medulloblastomas (G3MB) carry the worst prognosis among medulloblastoma subtypes, yet molecularly targeted therapies remain elusive. Standard treatments cause severe long-term morbidity in survivors. Here, we identify tumor-derived sphingosine kinase 2 (SPHK2) as an essential driver of G3MB initiation and progression. SPHK2 exacerbates local immunosuppression by suppressing cytotoxic T-cell and NK-cell activity while promoting regulatory T-cell infiltration. Genetic or pharmacologic SPHK2 inhibition using Opaganib attenuates pro-survival tumor signaling and restores anti-tumor immunity, significantly improving survival in syngeneic G3MB mouse models. Combining Opaganib with fractionated low-dose radiation (f-LDRT) further enhances antigen presentation and reprograms tumor-associated myeloid cells toward an anti-tumor phenotype. This combination therapy markedly prolongs survival without inducing significant toxicity. Overall, our study establishes SPHK2 as a previously unrecognized therapeutic target and presents a safe, effective, microenvironment-reprogramming regimen for G3MB. One Sentence SummaryDirect inhibition of tumor-derived SPHK2 overcomes local immunosuppression and downregulates pro-survival signaling in Group 3 medulloblastoma, while combination with fractionated low-dose radiation further enhances anti-tumor immunity and significantly improves survival.

cancer biology↗

Laser-integrated nanophotonic neural probes with on-chip sensors for addressable photostimulation

Studying the role of individual neurons in behavior and disease requires tools for controlling neural activity with high spatiotemporal resolution. Implantable nanophotonic neural probes are capable of delivering targeted photostimulation to enable genetically distinct neurons to be selectively controlled, yet face barriers to achieving scalable emitter densities and lack sensors for monitoring feedback signals relevant to device operation. To address this, we developed laser-integrated nanophotonic neural probes, which feature hybrid-integrated laser diodes (LD) and thermo-optic photonics switches for scalable emitter addressing and on-chip sensors for monitoring optical power and temperature during photo-stimulation. Devices were fabricated at a commercial silicon photonics foundry on 200-mm diameter silicon-on-insulator (SOI) wafers in an active visible-light platform and were controlled using a custom-developed electronic circuit board. Each device features a hybrid-integrated InGaN LD which couples 450-nm light into a reconfigurable photonic switching tree for delivering spatially resolved photostimulation through 16 emitters along a 3-mm implantable shank. Using the on-chip photodetectors, we demonstrate how devices can enable switching tree calibration as well as output power monitoring during photostimulation. Furthermore, using the on-chip temperature sensors, we show how device temperature perturbations resulting from LD and thermo-optic switch activation can be directly monitored during photostimulation to ensure temperature fluctuations remain below 1 {degrees}C. We validate our design by delivering high spatiotemporal photostimulation during an in vivo optogenetic experiment with simultaneous Neuropixels recording to monitor evoked responses. Overall, these scalable integrated devices offer a pathway for neuroscientists to conduct fiberless optogenetic experiments with greater control and precision.

neuroscience↗

A domain-swapped proPC1/3 structure reveals a conformational checkpoint for ER export

Prohormone convertase 1/3 (PC1/3, encoded by PCSK1) is a serine protease expressed in neuroendocrine cells that is required to produce insulin, glucagon-like peptide-1, adrenocorticotrophic hormone, and other peptide hormones. PC1/3 is synthesized as the zymogen proPC1/3, which undergoes autocatalytic maturation in the endoplasmic reticulum (ER) before trafficking to secretory granules. However, how autocatalytic maturation licenses the ER exit of PC1/3 remains unknown. Here, we determined the structure of an immature, catalytically inactive human proPC1/3S382A, which exits the ER as a domain-swapped homodimer. This domain-swapped conformation allows proPC1/3S382A to complete a conserved calcium pocket normally formed after autocatalysis and thereby become competent for ER exit. By defining this calcium pocket as a conformational checkpoint for ER export, our findings provide insights into the maturation of PC1/3 which may apply broadly to the PCSK family. Finally, our structure provides explanations for the functional consequences of many deleterious PCSK1 mutations.

biochemistry↗

High-Density Wild-Type IL-2 Nanoparticles Preferentially Enhance CD8⁺ T-Cell Expansion and Reprogram the Tumor Microenvironment

Low response rates to immune checkpoint inhibitors (ICIs) in solid tumors are often driven by insufficient tumor-infiltrating CD8 T cells and immunosuppressive tumor microenvironment (TME). Although interleukin-2 (IL-2) potently expands and activates CD8 T cells, its clinical use is limited by rapid clearance, dose-limiting toxicity, and regulatory T cell (Treg) stimulation. Engineered IL-2 variants have not yet achieved meaningful clinical efficacy. Here, polymer-modified mesoporous silica nanoparticles displaying dense, unmodified wild-type IL-2 on their surface (IL2-NP) are developed, conferring proteolytic stability and tumor retention. IL2-NP enables avidity-mediated CD8 T cell binding and enhances proliferation and effector function without increased Treg binding or proliferation. Intratumoral IL2-NP expands CD8 T cells, increases CD8/Treg ratios, and reprograms TME through dendritic cell activation and M1-like macrophage polarization. IL2-NP induces regression of both treated and untreated distant colorectal tumors in a CD8 T cell-dependent manner. IL2-NP synergizes with ICIs and leads to complete tumor regression and immunological memory that protect against rechallenge. Treatment is well tolerated, with strong efficacy also observed in triple-negative breast and metastatic ovarian cancer models. Overall, intratumoral IL2-NP elicits robust systemic antitumor immunity, offering a promising strategy to enhance ICIs, cancer vaccines, and adoptive T-cell therapies. Graphical abstractThis work introduces a nanoparticle platform that overcomes major shortcomings of IL-2 immunotherapy by presenting wild-type IL-2 at high density on the nanoparticle surface, thereby increasing binding avidity to effector T cells. The resulting IL-2 nanoparticles enhance cytotoxic T cell expansion, reprogram the tumor microenvironment, and augment responses to immune checkpoint blockade to achieve robust ant-tumor immune response in mouse tumor models. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=182 SRC="FIGDIR/small/738558v1_ufig1.gif" ALT="Figure 1"> View larger version (82K): org.highwire.dtl.DTLVardef@a53915org.highwire.dtl.DTLVardef@146c137org.highwire.dtl.DTLVardef@3734ccorg.highwire.dtl.DTLVardef@6b5aef_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

Immunoinformatics-Guided Design and In Silico Evaluation of a Multi-Epitope Vaccine Against Influenza A H10N5 and H3N2 Strains Based on Hemagglutinin and Neuraminidase Proteins

Influenza A viruses H3N2 and H10N5 represent, respectively, a persistently dominant seasonal pathogen and a newly documented zoonotic threat with the latter strain variants responsible for the first confirmed human fatality in January 2024, yet no vaccine platform currently addresses co-protection against both subtypes within a unified immunogen. We report here the immunoinformatics based vaccine design and multi-layered computational validation of a 419-amino-acid multi-epitope subunit vaccine construct targeting conserved hemagglutinin (HA) and neuraminidase (NA) antigens identified through multiple sequence alignment of the avian H10N5 (A/swine/Hubei/10/2008) and H3N2 human reference strain sequences to identify viral agents undergoing mammalian adaptations. Linear B-cell, cytotoxic T lymphocyte (CTL), and helper T lymphocyte (HTL) epitopes were predicted using ABCpred, BCEpred, BepiPred 2.0, NetMHCpan 2.1, and NetMHCpan 4.0, then filtered through VaxiJen 3.0, AllerTOP v2.1, and ToxinPred to retain only antigenic, non-allergenic, non-toxic candidates. The final construct, incorporating an avian {beta}-defensin N-terminal adjuvant with GPGPG, AAY, and EAAAK linkers, exhibited a molecular weight of 43.9 kDa, instability index of 31.15, and SOLPro solubility probability of 0.763. Tertiary structure modeling via I-TASSER and GalaxyRefine achieved 84.4% Ramachandran-favored residues. Molecular docking against TLR3 and TLR7 yielded binding free energies of -16.1 and -16.8 kcal/mol with picomolar dissociation constants. Molecular dynamics simulations confirmed complex stability over extended trajectories. Furthermore, codon optimization produced a Codon Adaptation Index of 1.0 for E. coli K12 expression. In silico immune simulation demonstrated robust activation of humoral and cellular immunity including elevated IgG1, IgM, IFN-{gamma}, IL-2, rapid NK cell expansion, and broad B-cell clonal diversity. These findings establish a computationally validated candidate capable of providing protection against influenza in multiple host organisms, warranting experimental advancement.

bioinformatics↗

PEPstrMOD2: Next-generation tertiary structure prediction of chemically modified and non-natural peptides

While most existing methods are limited to predicting the tertiary structures of proteins containing only canonical residues, the PEPstrMOD server (developed in 2015) pioneered structure prediction for chemically modified and non-natural peptides. Despite its widespread use, the original framework was restricted to peptides of 7 to 25 residues and relied on older backbone-prediction algorithms. To address these limitations, we present PEPstrMOD2, which introduces three major advancements over its predecessor. First, it replaces the original in-house coordinate generation with state-of-the-art deep learning (DL) algorithms, leveraging AlphaFold2 and ESMFold for highly accurate initial structure prediction. Secondly, it greatly expands the accessible chemical space through incorporation of new, AMBER force-field compatible library of 257 post-translational modifications (PTMs), 428 non-canonical amino acids (NCAAs), and 243 terminal modifications. Lastly, through the application of native scalability of AlphaFold2 (AF2) and ESMFold (EF), PEPstrMOD2 eliminates the original restrictions of the length, enabling the structural modeling of longer, complex therapeutic peptides and small proteins. We evaluated the performance of PEPstrMOD2 against state-of-the-art methods across three distinct peptide datasets. For the AfCyc dataset consisting of 80 cyclic peptides, PEPstrMOD2 obtained a competitive average atom-level Root Mean Square Deviation (RMSD) of 2.05 [A], compared to 1.13 [A] by AlphaFold3 (AF3) and 1.82 [A] by AfCycDesign. Remarkably, for the modified peptide ModPep433 dataset, PEPstrMOD2 outperformed AF3, achieving the lower average RMSD score of 4.49 [A] against 4.67 [A] of AF3. Furthermore, in the case of the ModPep16 benchmark, PEPstrMOD2 achieved 2.50 [A] average RMSD value, which is two times more accurate than that of the original PEPstrMOD (5.84 [A]). In summary, PEPstrMOD2 provides a powerful, high-throughput, and highly accurate platform to facilitate peptide-based drug development and structural biology research. While the original PEPstrMOD was restricted to a web server interface, PEPstrMOD2 is available as both an intuitive webserver and a standalone command-line tool via GitHub, featuring Docker support for easy deployment and reproducible, large-scale modeling pipelines (https://webs.iiitd.edu.in/raghava/pepstrmod/). HighlightsO_LIPEPstrMOD2 predicts structures of chemically modified peptides using deep learning and molecular dynamics refinement. C_LIO_LISupports 928 chemical modifications through custom AMBER based force-field libraries including PTMs, NCAAs, terminal, D- as well as cyclic modifications. C_LIO_LIRemoves peptide length restrictions through AlphaFold2 and ESMFold integration. C_LIO_LIutperforms PEPstrMOD and is competitive with AF3 on different benchmark datasets. C_LIO_LIAvailable as both a web server and a standalone platform via GitHub and Docker. C_LI Authors BiographyO_LISaloni Jain is currently working as Ph.D. in Computational biology from Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India C_LIO_LINaman Kumar Mehta is currently working as Ph.D. in Computational biology from Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India C_LIO_LISahil Raina is currently working as Ph.D. in Computational biology from Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India C_LIO_LIPankaj Kumar is currently working as Ph.D. in Computational biology from Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India C_LIO_LIVarun is currently an integrated BS-MS student at Indian Institute of Science Education and Research (IISER) Pune, India. He is currently working as an intern on a project position at Department of Computational Biology, Indraprastha Institute of Information Technology (IIIT), New Delhi, India. C_LIO_LIGajendra P. S. Raghava is currently working as a Professor in the Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India. C_LI

bioinformatics↗

Distinct Programs of Tissue Adaptation Shape Vitreous CD4+ and CD8+ T-cell States in Chronic Uveitis

Tissue-resident memory (TRM) T-cells are increasingly recognized as key mediators of chronic autoimmune inflammation, yet their organization and functional adaptation within the eye remain poorly understood. We investigated paired vitreous body biopsies and peripheral blood T cells from patients with chronic posterior segment uveitis using multiparameter flow cytometry, antigen-specific stimulation assays, single-cell RNA sequencing, and T-cell receptor sequencing to define the intraocular tissue-adaptive immune states. Vitreous T cells were phenotypically, transcriptionally, and clonally distinct from their circulating counterparts and enriched for canonical TRM markers. However, tissue adaptation differed substantially between CD4+ and CD8+ lineages. Vitreous CD4+ T cells segregated into clonally expanded tissue-adaptive states characterized by greater CXCR6 expression, enhanced antigen-specific cytokine responses, and well-defined transcriptional profiles. In contrast, vitreous CD8+ T cells expressed higher levels of the retention-associated markers CD103 and CD49a yet maintained greater clonal and phenotypic continuity with peripheral blood T cells. Both vitreous CD4+ and CD8+ subsets exhibited a restrained effector profile associated with tissue-adaptive transcriptional programs. Our data reveal that CD4+ and CD8+ T cells in chronic uveitis assume distinct states in the vitreous microenvironment, such that the intraocular immune response relies on both localized tissue retention and active adaptation to the inflammatory niche.

immunology↗

In vitro-reconstituted Drosophila Arc capsids deliver gene editors to dystrophic muscle

The intracellular delivery of therapeutic macromolecules remains a major challenge in biomedicine. Here we reconstitute the Drosophila melanogaster Arc1 (dArc1) retroelement-derived capsid entirely from purified recombinant protein components and in vitro transcribed RNA, creating a fully defined, cell-free assembled protein nanoparticle system. Through affinity engineering of the dArc1 RNA-binding domain, we enable efficient encapsulation of mRNA payloads and Cas9 ribonucleoproteins. Unexpectedly, we discover that dArc1 capsids bind mammalian cells through a direct interaction with the surface receptor SORCS2. Leveraging this interaction, we show that intramuscular injection of dArc1 capsids carrying Cas9 gene editors achieves up to 18% exon skipping and restores dystrophin expression in muscle fibers of mdx mice, a model of Duchenne muscular dystrophy. Enhanced delivery efficiency in regenerating and dystrophic muscle correlates with upregulated SORCS2 expression, supporting our finding that SORCS2 facilitates cellular uptake of dArc1 capsids. This work demonstrates the potential of in vitro-assembled protein nanoparticles for delivery of molecular cargoes.

molecular biology↗

Age Dependent Immunopathology Drives Pneumonia-Associated Cardiac Dysfunction During Streptococcus pneumoniae Infection

Aging is a major risk factor for severe Streptococcus pneumoniae (Spn) infection and pneumonia-associated - major adverse cardiac events (PA-MACE), yet underlying mechanisms remain unclear. Using young and aged murine models, we show that aging exacerbates bacterial burden, mortality, and cardiac dysfunction following Spn infection, associated with impaired macrophage bacterial killing. Single-cell RNA sequencing infected hearts revealed extensive age-dependent remodeling across immune and stromal compartments. Aged mice exhibited heightened pro-inflammatory myeloid responses, with increased neutrophil infiltration characterized by elevated S100A8/9 and LCN2 and reduced antimicrobial programs. Macrophages displayed defective efferocytosis, including disruption of the GAS6-AXL axis. Aging also drove expansion of an infection-responsive fibroblast population with inflammatory signatures and reduced extracellular matrix gene expression. These changes were linked to oxidative stress and impaired glucose oxidation. Notably, anti-inflammatory treatment rescued cardiac dysfunction, implicating excessive inflammation as a central driver of PA-MACE. Together, these findings define mechanisms linking aging to pneumococcal cardiac complications and identify potential therapeutic targets.

immunology↗

Pharmacokinetic Acceleration via CYP3A4 Hyperactivation as a Clinically Actionable Mechanism of Targeted Therapy Resistance in NSCLC

Resistance of cancers to targeted therapies is traditionally framed as a tumor-intrinsic phenomenon, mediated by tumor cell-intrinsic or microenvironmental mechanisms. Here, we identify a tumor-extrinsic, systemic resistance mechanism resulting from hyperactivation of the hepatic cytochrome P450 enzyme, CYP3A4. This tumor-extrinsic resistance mechanism can function independently of, or in tandem with, tumor-intrinsic resistance. Focusing on experimental mouse models of targetable lung cancer, we find that xenobiotic-mediated induction of CYP3A4 results in accelerated drug metabolism and a drastic reduction in systemic and tumor-drug exposure in vivo. CYP3A4 activation can be triggered by chemically unrelated xenobiotics, leading to resistance to a wide range of targeted therapies, including ALK, EGFR, and KRASG12C inhibitors. Retrospective analysis of clinical cohorts suggests that variability in CYP3A4 activity might be a major contributor to variability in clinical outcomes. While higher CYP3A4 activity leads to sub-therapeutic tumor drug exposure and shorter progression-free survival, reduced drug metabolism is expected to result in supratherapeutic exposure and increased systemic toxicity. To address the consequences of abnormal CYP3A4 activity, we utilized mathematical modeling to demonstrate that drug concentrations can be restored through the optimization of dosing amounts and intervals. Further, we show that tumor sensitivity to targeted therapies can be rescued through pharmacological inhibition of CYP3A4. Our findings establish systemic metabolic variability as a bona fide resistance and toxicity driver, providing a translational framework for personalized dosing to maximize both safety and efficacy.

cancer biology↗