Biology subjects

Mitra, S.

Publications and source records attributed to Mitra, S..

At least 37 records · Page 2Linked to original sources

bioRxiv2026

CD99Targeted Irinotecan Containing Nanoparticles Show Twenty-Fold Greater Anti-Tumor Effect Than Free Irinotecan For Treatment of EwingSarcoma

PurposeTo assess the antitumor efficacy, pharmacokinetics, and safety of NV103, a CD99-targeted liposomal irinotecan nanoparticle, in a preclinical Ewing sarcoma model. Experimental DesignNV103 is a CD99-antibody targeted irinotecan containing nanoparticle, engineered to selectively deliver irinotecan to CD99 expressing tumor cells. In vitro studies measured binding, internalization, and cytotoxic IC50 values in several Ewing sarcoma cell lines. In vivo, mice bearing xenografts derived from treatment-naive and chemoresistant Ewing lines were treated. NV103 was compared with free irinotecan, untargeted nanoparticles, and OnivydeTM at multiple dosages. Plasma pharmacokinetics of irinotecan and SN-38, biodistribution of the nanoparticles, and toxicity (body weight, organ function, and hematology) were assessed. ResultsNV103 bound selectively to tumor cells (>80x over control), was rapidly internalized, and showed enhanced potency in vitro (IC50 {approx} 3-4 nM at 0.5-1 h). In vivo, biweekly dosing at 5 mg/kg resulted in full tumor regression sustained for 140 days, even after stopping treatment at day 70. Effective suppression and survival benefit were observed at doses as low as 1 mg/kg; the ED50 was estimated to be between 1-2.5 mg/kg versus 50mg/kg for free irinotecan. In a chemoresistant Ewing tumor cell line, NV103 induced similar tumor-free remission. Pharmacokinetics revealed prolonged and elevated plasma levels of irinotecan with NV103 versus free drug. No systemic toxicity was detected at doses of 10 mg/kg. Biodistribution showed tumor-preferential accumulation. ConclusionsNV103 displays potent and durable antitumor activity in Ewing sarcoma at low doses with no toxicity and favorable pharmacokinetics. These findings support further development for clinical translation. Translational RelevanceAlthough Irinotecan has shown activity against Ewing sarcoma, its clinical utility is limited by systemic toxicity and poor tumor selectivity. NV103, a CD99-targeted nanoparticle formulation of irinotecan delivers irinotecan selectively to Ewing sarcoma cells. CD99 is a surface antigen that is highly expressed in Ewing sarcoma cells but largely absent from irinotecan-sensitive organs like liver, kidney, and bone marrow. In preclinical xenograft models, NV103 induced complete and durable tumor regression at doses >10 fold lower than those of free irinotecan or untargeted nanoparticles, with no detectable systemic toxicity. These findings suggest that NV103 is a promising translational therapeutic agent that enhances the therapeutic index of irinotecan and other cytotoxic agents. This platform offers a broadly adaptable approach to tumor-specific drug delivery, which could significantly improve treatment outcomes and reduce long-term toxicity in children and young adults with Ewing sarcoma and other solid tumors.

cancer biology↗

bioRxiv2026

Tumor-infiltrating natural killer cell profiling for therapeutic stratification in patients with resectable non-small cell lung cancer

ObjectiveNeoadjuvant chemoimmunotherapy has improved outcomes in resectable non-small cell lung cancer (NSCLC), yet its real-world implementation is often challenged by surgical delays, immune-mediated fibrosis, and postoperative complications. Smokers with NSCLC, despite a high risk for surgical morbidity, show enhanced responses to neoadjuvant chemoimmunotherapy. This study aimed to identify smoking-associated immune cell determinants that could guide treatment strategies. MethodsSingle-cell RNA sequencing (scRNAseq) was performed on 61 lung tissues from non-smokers and smokers to identify smoking-related immune compositions. The scRNAseq data from 19 invasive lung adenocarcinomas were used to validate their presence in the tumor-immune microenvironment. Bulk RNA sequencing data from 102 resected NSCLC and 24 NSCLC patients treated with neoadjuvant chemoimmunotherapy followed by surgery were used for in silico cellular deconvolution and outcome analyses. ResultsAmong 135 lung cellular phenotypes, two natural killer (NK) cell subsets were strongly associated with smoking and chronic obstructive pulmonary disease (COPD) severity. "Stress-responsive" NK (NKSR) cells exhibited immature features and cytokine-responsive features, and "Adaptive and immunoregulatory NK" (NKAIR) cells showed mature features and elevated multiple immune checkpoint expression. High intratumoral NKSR cells correlated with improved survival after surgery, particularly in current smokers. Conversely, tumors with low NKSR and high NKAIR cells responded more favorably to neoadjuvant chemoimmunotherapy. ConclusionsIntratumoral NK cell phenotyping may aid in therapeutic stratification in patients with NSCLC. NKSR cell preservation predicts benefit from upfront surgery, while NKAIR cell enrichment indicates improved response to neoadjuvant chemoimmunotherapy. These NK cell profiles may help optimize treatment by balancing therapeutic benefit and risk. Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/696292v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@168bc03org.highwire.dtl.DTLVardef@10fa947org.highwire.dtl.DTLVardef@132a92dorg.highwire.dtl.DTLVardef@100e4a4_HPS_FORMAT_FIGEXP M_FIG C_FIG Central Picture O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/696292v1_ufig2.gif" ALT="Figure 2"> View larger version (21K): org.highwire.dtl.DTLVardef@1a2d3b4org.highwire.dtl.DTLVardef@f8f84borg.highwire.dtl.DTLVardef@17510bcorg.highwire.dtl.DTLVardef@9da763_HPS_FORMAT_FIGEXP M_FIG C_FIG NK cell profiling for treatment stratification in resectable NSCLC Central MessageTumor-infiltrating NK cell profiling identifies distinct immune phenotypes that can inform personalized treatment strategies in resectable NSCLC. Perspective statementAbundance of intratumoral stress-responsive NK cells predicts favorable outcomes after upfront surgery, whereas enrichment of adaptive and immunoregulatory NK cells suggests greater benefit from neoadjuvant chemoimmunotherapy. These findings support incorporating NK-cell profiling into preoperative decision-making to optimize therapy selection and balance risks in the high-risk surgical population.

immunology↗

bioRxiv2025

Loss of noradrenergic Fkbp5 disrupts social behavior and norepinephrine dynamics in the basolateral amygdala

Social dysfunction is common in depression and varies with stress exposure and genetic risk. The current study identifies a cell-type specific role for Fkbp5, a glucocorticoid receptor co-chaperone, in noradrenergic neurons engaged during social stress. Acute social stress upregulated Fkbp5 in the locus coeruleus (LC), whereas repeated exposure attenuated this effect. Noradrenergic Fkbp5 deletion (Fkbp5Nat) increased pro-social behavior exclusively in male mice. In the basolateral amygdala (BLA), social interaction reduced norepinephrine (NE) turnover in wild-type but not Fkbp5Nat mice. Consistently, proteomics revealed mitochondrial/energy and synapse-related remodeling in BLA neurons. Miniscope imaging showed that behavior-locked NE transients in BLA were selectively blunted in Fkbp5Nat mice during interaction with outbred CD1 conspecifics, while same-strain C57BL/6N encounters preserved NE dynamics. Together, this study indicates that Fkbp5 tunes LC-BLA output to social salience in a sex- and context-dependent manner, suggesting a circuit-specific route to normalize social salience without broadly suppressing noradrenergic function.

neuroscience↗

bioRxiv2025

Emergent Morphologies, Slow Dynamics, and Phase Behavior in Dps:DNA assemblies

The DNA-binding protein from starved cells (Dps) compacts bacterial DNA into stress-protective condensates, but the physical ingredients that are sufficient to produce the observed morphological and dynamical phenomenology remain unclear. Here we use Dps:DNA as the motivation for a broader soft-matter question: which properties govern the co-condensation of a semiflexible polymer with a binding co-solute, and how is the resulting condensate morphology selected? We combine coarse-grained Brownian dynamics (BD) simulations, in which DNA is a semiflexible bead-spring chain and Dps a spherical particle interacting through heterotypic attraction and homotypic repulsion, with a ternary Flory-Huggins free energy evolved under conserved Cahn-Hilliard-Cook dynamics. Both frameworks show that the condensate morphology is governed jointly by the heterotypic Dps:DNA attraction and by composition: attraction drives co-condensation, while at fixed attraction the relative abundance of the two species selects between extended, network-like structures and compact, droplet-like condensates. That two independent models, sampling different concentration regimes, both show composition-controlled morphology selection indicates it is a robust feature of the co-condensation thermodynamics. The simulations further reveal slow, heterogeneous dynamics: sub-diffusive Dps motion and a stretched-exponential collapse of chain dimensions, signatures of the dynamical arrest that accompanies compaction. The framework provides general, transferable principles for protein-nucleic-acid phase separation in soft and living matter.

biophysics↗

bioRxiv2025

Targeted Nanoparticles: an Innovative Modality in the Treatment of Cancer

Despite progress made in the development of anticancer therapeutics, traditional small-molecule chemotherapeutics often struggle to overcome toxicity, efficacy, and off-target effects. These specific issues can be overcome by either encapsulating the drug or by targeting it directly to the tumor cell. Here, we describe a novel targeted nanoparticle (referred to as a nano-antibody-drug conjugate Targeted Nanosphere or nADC/TNS), based cancer therapeutic platform that can improve the efficacy of a broad range of existing therapeutics. Targeting is antibody-directed, as with antibody-drug conjugates (ADCs). Still, the payload per antibody is vastly greater by orders of magnitude (a thousand for nADC/TNS versus two to eight for ADCs). The nADC/TNS consists of an approximately 80 nm drug-filled nanoparticle composed of phospholipids, cholesterol, and UV cross-linkable diacetylene lipids. We describe the preparation, characterization, and evaluation of nADC/TNS as a novel, versatile, and effective treatment modality for cancer and potentially other diseases. This report focuses on data with nADC/TNS variants NV101 (anti-CD99 targeted, doxorubicin-filled), NV102 (anti-CD19 targeted, doxorubicin-filled), and NV103 (anti-CD99 targeted, irinotecan-filled). We investigated NV101 and NV103 in a mouse model with implanted and metastatic Ewing tumors (ES). NV101 demonstrated significant tumor burden reduction while NV103 induced complete ablation of ES tumors. NV102 demonstrated complete ablation of chemotherapy-resistant relapsed adult lymphocytic leukemia (ALL). These results document the potential superior efficacy of antibody-targeted nanoparticles containing a variety of small-molecule payloads, compared to their free molecule equivalents.

biochemistry↗

bioRxiv2025

Conformational Diversity and Allosteric Network Enable Multi-Substrate Recognition in Laccase Enzyme

Laccase is a multicopper oxidase with remarkable potential for environmental remediation due to its ability to degrade a wide range of pollutants. However, the molecular origins of its broad substrate scope have remained elusive. Here, through extensive molecular dynamics (MD) simulations coupled with machine learning (ML) based Markov State Model (MSM), we uncover a previously uncharacterized allosteric pathway that governs laccases catalytic activity. This pathway functionally couples the dynamics of two key loops at the active site, and its integrity is crucial for enzymatic efficiency. Our analysis of the apo enzymes conformational free energy landscape reveals that this allostery is part of a cooperative global network, leading to distinct, slowly interconverting conformational states. We demonstrate that different dye substrates bind by selectively recognising these pre-existing states, confirming a conformational selection mechanism. Collectively, these findings provide a dynamic blueprint for laccases functional versatility and offer a general framework for understanding and engineering other multi-substrate enzymes.

biophysics↗

bioRxiv2025

The Rise and Fall of SARM1 Base-Exchange Inhibitors

The sterile alpha and TIR motif containing 1 (SARM1) enzyme is a key driver of axonal degeneration in response to injury, making it an attractive target for treating chemotherapy-induced peripheral neuropathy (CIPN) and other nervous system diseases. In this study, we identified and optimised a new class of base-exchange inhibitors (BEXi) targeting SARM1 and explored their molecular interactions and conformational effects using cryo-EM, HDX-MS and SAXS. Although BEXi produced robust inhibition across all biochemical and cellular assay formats, application at sub-inhibitory concentrations consistently led to paradoxical SARM1 activation, and in neuronal assays, accelerated neurite degeneration. Further analysis showed that BEXi only delayed, rather than prevented, neurite degeneration when applied to primary neuronal cells, even at exceedingly high inhibitor concentrations. These results prompted us to discontinue BEXi development in favour of alternative strategies, underscoring the complexity of SARM1 as a therapeutic target and the need for comprehensive, mechanistically informed screening cascades.

neuroscience↗

bioRxiv2025

Novel truncating Desmin mutation Arg150Stop disrupts structural integrity and cellular homeostasis by formation of persistent aggregate-like structure

Desminopathies are a heterogeneous group of myofibrillar myopathies defined by the presence of desmin-positive aggregates that compromise cytoskeletal integrity in skeletal and cardiac muscle. Although desmin knockout models and several truncating mutations typically result in a functional null phenotype without inclusion body formation, the molecular consequences of specific stop-gain variants remain poorly understood. In this study, we investigated the pathogenic mechanism of a novel DES nonsense mutation, NM_001927.4:c.448C>T; p.(Arg150Stop), previously identified in an Indian patient with congenital myopathy. This premature stop codon lies within the Linker 1A domain and is predicted to generate a truncated protein lacking the C-terminal tail. To delineate its functional consequences, we used two complementary experimental approaches: transient overexpression of the R150X mutant in skeletal and cardiac myocytes, and a CRISPR/Cas9-engineered homozygous R150X cardiomyocyte line (Des-R150X-CRISPR). Both models consistently revealed the formation of persistent aggregate-like structures, in striking contrast to desmin knockout systems that do not generate inclusions. These aggregate-like structures disrupted actin filament organization, impaired filament bundling, and induced organelle mislocalization. Biochemical analysis indicated that the aggregates were resistant to proteasomal degradation, yet they were partially cleared by autophagy, underscoring a role for protein quality control pathways in modulating disease severity. Importantly, the Des-R150X-CRISPR line demonstrated aggregate-driven pathology at endogenous levels, confirming that this mutation acts through a toxic gain-of-function mechanism rather than simple loss of desmin function. Our findings establish the Arg150Stop variant as a mechanistically distinct truncating mutation that generates aggregation-prone protein rather than a null state. By reproducing hallmark features of desminopathy in a physiologically relevant human cell models, this work not only broadens the known pathogenic spectrum of DES variants but also highlights aggregate formation as a central driver of cellular dysfunction and a promising therapeutic target in desminopathies.

cell biology↗

bioRxiv2025

The novel curcumin analogue AKT-100 targets mutant p53 in gynecologic cancer cells

Loss of normal p53 tumor-suppressive activity is common in advanced cancers, where TP53 mutations produce either p53-null states or highly expressed missense proteins with gain of oncogenic function. Mutant p53 proteins not only lose wild type p53 pro-apoptotic and DNA repair functions but also acquire new activities, including constitutive STAT3 activation. We hypothesize that directly targeting missense mutant p53 instead of downstream pathways is advantageous. Curcumin analogues have been reported to bind mutant p53, motivating the development of AKT-100, a novel analogue designed to restore wild type p53 functionality. AKT-100 binds mutant p53 and STAT3, as shown by fluorescence quenching, and inhibits STAT3 Tyr705 phosphorylation in KLE and COV362 cells. This agent exhibits potent cytotoxicity in gynecological cancer cells with IC50 values ranging from 4 nm to 2.51 {micro}M, and demonstrates synergy with the PARP inhibitor olaparib and with chemotherapy by suppressing alternative DNA repair mechanisms associated with therapeutic resistance. RNA sequencing and immunoblotting confirms AKT-100 reactivates wild type p53 transcriptional profiles regulating cell cycle arrest (CDKN1A/p21, GADD45A), apoptosis (PMAIP1/Noxa, DR5), and inhibits DNA replication and repair. These findings support AKT-100 as a promising therapeutic agent with the dual capabilities of directly targeting oncogenic mutant p53 and constitutively active STAT3. HighlightsO_LIAKT-100 is a novel curcumin analogue that functions as a WT p53 reactivator. C_LIO_LIAKT-100 inhibits STAT3 phosphorylation at Tyrosine 705 in endometrial and ovarian cancer cells. C_LIO_LICell proliferation is inhibited in multiple ovarian and serous endometrial cancer cell lines with AKT-100 as a single agent. C_LIO_LIAKT-100 is synergistic with PARP inhibitor olaparib and chemotherapy drugs carboplatin and paclitaxel. C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=132 SRC="FIGDIR/small/680794v3_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@1fdb8a8org.highwire.dtl.DTLVardef@6648acorg.highwire.dtl.DTLVardef@12d301aorg.highwire.dtl.DTLVardef@1b1370f_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2025

Exploring the evolutionary divergence of cyclic di-nucleotide signaling in diverse mycobacterial species

Cyclic dinucleotides (CDNs), such as cyclic di-AMP (c-di-AMP) and cyclic di-GMP (c-di-GMP), are key second messengers that regulate fundamental bacterial processes, including cell wall synthesis, biofilm formation, antibiotic resistance, stress response, and virulence. These pathways are particularly relevant in major pathogens like Mycobacterium tuberculosis. Increasing evidence highlights the pathogenic potential of non-tuberculous mycobacteria (NTM), originally environmental species that are emerging as significant human pathogens. Understanding the evolution of CDN signaling may therefore provide critical insights into this transition. Our comparative genomic analysis revealed that the c-di-AMP synthase disA is present as a single copy in nearly all mycobacterial genomes, except within the genus Mycolicibacter. The corresponding phosphodiesterases, PDE and AtaC, are variably distributed, with pathogenic mycobacteria showing a preference for PDE over AtaC. In contrast to the relatively conserved c-di-AMP system, the c-di-GMP pathway comprising diguanylate cyclases (DGCs) and phosphodiesterases (PDEs), exhibits remarkable variation in gene presence/absence and domain architecture across the Mycobacteriaceae family. This diversity suggests multiple independent gene gain and loss events throughout evolution, often accompanied by the acquisition of accessory domains. Evolutionary analyses indicate that disA, like core housekeeping genes, is under strong purifying selection, while pde shows relatively low diversity, reinforcing the idea that c-di-AMP signaling is highly conserved and essential across mycobacteria. By contrast, the c-di-GMP system is more heterogeneous, reflecting its role in environmental adaptation. Together, these findings highlight a sharp evolutionary divergence in CDN signaling, where c-di-AMP appears indispensable for core physiology, whereas c-di-GMP provides flexibility for niche-specific adaptation within the Mycobacterium genus.

microbiology↗

bioRxiv2025

To jump or not to jump: Comparing effects of phenotypic plasticity on the visual responses and escape behavior of locusts and grasshoppers

Locusts exhibit remarkable phenotypic plasticity changing their appearance and behavior from solitary grasshoppers to gregarious locusts when population density increases. These changes include morphological differences in the size and shape of brain regions, but little is known about plasticity within individual neurons and alterations in behavior not directly related to aggregation or swarming. We examined looming escape behavior and the properties of a well-studied collision-detection neuron in gregarious and solitarious animals of three closely related species, the desert locust (Schistocerca gregaria), the Central American locust (S. piceifrons) and the American bird grasshopper (S. americana). For this neuron, the lobula giant movement detector (LGMD), we examined dendritic morphology, membrane properties, gene expression, and looming responses. Gregarious animals reliably jumped in response to looming stimuli, but surprisingly solitarious desert locusts did not produce escape jumps. These solitarious animals also had smaller LGMD dendrites. This is the first study done on three different species of grasshoppers to observe the effects of phenotypic plasticity on the jump escape behavior, physiology and transcriptomics of these animals. Surprisingly, there were little differences in these properties between the two phases except for behavior. For all the three species, gregarious animals jumped more than solitarious animals, but no significant differences were found between the two phases of animals in the electrophysiological and transcriptomics studies. Our results suggest that phase change impacts mainly the motor system and that the physiological properties of motor neurons need to be characterized to understand fully the variation in jump escape behavior across phases. New & Noteworthy (74 words): Swarming is observed in some grasshopper species, called locusts. We compared jump escape behavior between gregarious and solitarious grasshoppers and locusts, as well as LGMD responses to looming stimuli, and analyzed the morphological differences in this neuron. This study provides insights into the effects of phase change on the visual system of locusts and grasshoppers as it relates to looming-evoked jump escape behavior. In this context, our results suggest that phenotypic plasticity mainly impacts the motor system.

neuroscience↗

bioRxiv2025

The Cornea Harbors a Tricellular Neuro-Immune Niche that Underpins Touch Sensation

Piezo2 is a mechanosensitive ion channel essential for touch and proprioception, yet the mechanisms that maintain this sensory modality in adult tissues are unknown. Using multiphoton imaging of the cornea in live mice, we discovered that the Cx3cr1Cre locus targets not only macrophages, but also a distinct subset of nerves. Spatial-RNAseq resolved that Cx3cr1Cre-driven labeling was uniquely enriched in Piezo2-expressing neurons, a result of temporal Cx3cr1 expression during development. Through lineage tracing, scRNAseq, and imaging, we identified a novel tripartite cellular niche at the epithelial basement membrane, comprised of monocyte-derived macrophages, nerves, and Schwann cells. Additional scRNAseq and genetic studies revealed that Schwann cell-derived IL34 maintained corneal macrophages. Through pharmacologic and genetic perturbations, we also demonstrate corneal macrophages selectively maintained the structure-function of Piezo2-enriched nerve endings, with disruption of this niche causing specific deficits in mechanosensation while preserving other sensory modalities. Altogether, we describe a novel tricellular niche in the cornea required for Piezo2-mediated touch sensation, suggesting new directions for investigating mechanosensory circuits including proprioception.

immunology↗

bioRxiv2025

Tonic GABAA receptor currents in Cerebellar Purkinje cells of wild-type and DMDmdx mice

Cerebellar Purkinje cells (PCs) fire spontaneously in the absence of excitatory input and depend heavily on inhibition to modify their firing activity. Previous work in the field has described phasic inhibition arising primarily from molecular layer interneuron-PC (MLI-PC) synapses extensively, however little work explores other sources of inhibition in PCs. Several types of neurons throughout the brain and within the cerebellum receive significant inhibition through tonic currents, a low amplitude current resulting from ambient GABA acting upon extrasynaptic GABAA receptors. Through the use of ex vivo electrophysiology and single cell RNA analysis, we investigated the role of tonic inhibition in PCs. We find that PCs have a significant tonic current mediated by {delta}-subunit containing GABAA receptors, which accounts for roughly half of the total inhibitory current. We also examined PC tonic GABA currents in DMDmdx mice, a mouse model of Duchenne Muscular Dystrophy with [~]50% reduction in phasic inhibitory currents. We find that tonic inhibition is dramatically upregulated in DMDmdx PCs, suggesting a possible compensatory mechanism to account for the loss in phasic inhibition. Furthermore, roughly 80% of the total inhibition is derived from tonic currents in this condition. These data suggest that under physiological conditions, PCs are subject to both tonic and phasic inhibition, and that adjustments in the balance of inhibition may be a physiological mechanism for PC function. These data reveal an expanded range of inhibitory currents in PC which may be critical to regulating PC activity in both normal and pathophysiological states.

neuroscience↗

bioRxiv2025

Convolvulus pluricaulis mediates its pharmacological effects via sod1, rdl, glut1, GABA-B-R1 and CG6293 orthologs in Drosophila melanogaster

Convolvulus pluricaulis, commonly known as Shankhpushpi, has been extensively used in the management of disorders of the nervous system, including depression and anxiety. The plant extract has also been demonstrated to function as an antioxidant. However, the molecular effectors underlying the beneficial effects of Shankpushpi are yet to be identified. In this study, we have utilized the fruit fly Drosophila melanogaster to identify the metabolic and molecular targets that mediate the beneficial effects of dietary Shankpushpi intake. Metabolomic analysis revealed changes in Ascorbic acid, glucose, and Adenosine monophosphate in the head tissue of fruit flies that were fed Shankpushpi for 20 days. Subsequent gene expression analysis revealed significant changes in expression of glut 1 (Glucose transporter 1), CG6293 (Ascorbate transporter), rdl (Resistant to dieldrin), GABA-B-R1 (GABA-B receptor subtype 1) and sod 1 (Superoxide dismutase 1) in the head tissue of adult flies that were exposed to different doses of Shankpushpi. Consistent with the expression data, knockdown of sod 1, glut1, GABA-B-R1, and CG6293 but not sod 2 abolished the Shankpushpi-mediated resistance to paraquat-induced oxidative stress. To uncover downstream effectors that are responsible for the antidepressant and anxiolytic effects of Shankpushpi, we examined the effects of dietary intake of Shankpushpi in a stress-induced model of depression. Administration of Shankpushpi during development alleviated depression-like behavior in Drosophila. Wild-type adult flies that were fed Shankpushpi accumulated high levels of Ascorbate in the head tissue, and knockdown of Ascorbate transporter abolished the antidepressant activity of Shankpushpi in the stress-induced model. Thus, indicating that Shankpushpi-induced antidepressant effects are associated with increased Ascorbate transport. Taken together, our analysis using Drosophila melanogaster as a model has uncovered five conserved downstream effectors responsible for the antioxidant activity and one conserved effector responsible for the antidepressant activity of Convolvulus pluricaulis.

molecular biology↗

bioRxiv2025

Polystyrene and polyethylene terephthalate nanoplastics differentially impact mouse ovarian follicle function

Exposure to micro- and nanoplastics is unavoidable. Foods and beverages contain plastic particles from environmental contamination and processing and packaging materials, which are frequently made of polyethylene terephthalate (PET). Micro- and nanoplastics have been detected in human tissues such as the brain, liver, and placenta, as well as in ovarian follicular fluid, but little is known about the effects nanoplastics have on the female reproductive system. In addition, few studies on the health impacts of nanoplastics have been performed using environmentally relevant plastic types and concentrations. Thus, this research tested the hypothesis that nanoplastics made of spherical polystyrene (PS), a common model nanoplastic, would have different effects on cultured mouse ovarian follicles compared to secondary PET nanoplastics at environmentally relevant doses. The ovary is a highly sensitive reproductive organ responsible for the development of follicles, which contain the oocyte, and production of steroid hormones. Follicles were harvested from adult mouse ovaries and cultured for 96 h with vehicle, spherical commercially available 200 nm PS nanoplastics (1-100 {micro}g/mL), or lab-generated 240 nm PET nanoplastics (0.1-10 {micro}g/mL). PS and PET nanoplastic exposure inhibited follicle growth and altered expression of genes related to steroid synthesis, cell cycle, and oxidative stress. PET nanoplastics increased levels of pregnenolone and decreased expression of Cyp17a1. Overall, both plastic types altered ovarian function, but they impacted different genes in similar pathways. These findings suggest that nanoplastic exposure at environmentally relevant concentrations may pose a risk to female reproductive health by disrupting hormonal and molecular pathways. In addition, environmentally relevant plastic types and doses are necessary for studying health impacts of nanoplastics. HighlightsO_LINanoplastics disrupted ovarian function in vitro C_LIO_LISecondary PET and virgin PS differently inhibited follicle growth and ovarian gene expression C_LIO_LIPET exposure increased pregnenolone, impacting steroid hormone pathways C_LIO_LIEnvironmentally relevant plastics can harm female reproductive health C_LI

pharmacology and toxicology↗

bioRxiv2025

A scalable framework for current steering at single-neuron resolution

Electrical stimulation at cellular resolution to restore the function of neural circuits is limited by the density of available electrode arrays. Although current steering with multi-electrode stimulation can be used to target cells between electrodes, it has not been proven for systematically targeting individual cells. We develop a framework for cellular-resolution current steering, leveraging the biophysics of electrically-evoked spike generation, and test its efficacy in isolated macaque and human retina. Currents were passed through three electrodes simultaneously using large-scale high-density microelectrode arrays, directly evoking single spikes in retinal ganglion cells. The currents combined either linearly or nonlinearly to drive spiking, depending on the geometry of the electrodes relative to the cell. These findings were captured by a biophysical model and by a simpler parametric model in which spikes can initiate at several sites on the cell membrane, and were leveraged to efficiently identify multi-electrode stimulation patterns that optimized cellular selectivity.

bioengineering↗

bioRxiv2025

Unraveling the distinct motion bias of TrkA-NGF complex in NGFR100W-driven HSAN V disease

Nerve growth factor (NGF), which binds to tropomyosin-related kinase A (TrkA) receptor, plays essential roles in neuronal survival and function and is also a potent mediator of pain sensation. Mutations in NGF, particularly NGFR100W, cause hereditary sensory autonomic neuropathy V (HSAN V), which is characterized by insensitivity to pain but without impairment of neurotrophin function. Even though several studies reported the mechanism of growing HSAN V disease, the dynamic mechanisms that dictate its functional specificity remain unclear. In this study, we performed a microsecond scale molecular dynamics (MD) simulation to elucidate the changes in the structural dynamics of NGF by NGFR100W at an atomic level to dissect the distinct motion bias for specific TrkA functions. We found that the NGFR100W reduced NGF dimerization while its binding to the TrkA remained unchanged. NGFR100W enhanced the magnitude of bond formation in the different regions from TrkA, which induced different correlated and dynamic motions associated with impaired nociceptive signaling. The dynamics scenario from this study, shedding light on the deleterious role of NGFR100W, provides new structural insights into the function-oriented dynamics motion of the TrkA-NGF complex, offering potential avenues for designing new therapeutics.

neuroscience↗

bioRxiv2025

Anti- and Pro-tumor Functions of Distinct Regulatory T Cell Subsets in Colorectal Cancer

Regulatory T (Treg) cells contribute to solid organ cancer progression, except in colorectal cancer (CRC) despite being abundantly present. Here, we demonstrate that two distinct tumoral IL-10 and IL-10- Treg cell subsets exert opposing functions by counteracting and promoting CRC tumor growth, respectively. The tumor restraining activity of IL-10 Treg cells was mediated by their suppression of effector CD4 T cell production of IL-17, which directly stimulates CRC tumor cell proliferation. Consistently, IL-10- Treg cells were more abundant in both mouse and human CRC tumors than in tumor-adjacent normal tissues, whereas IL-10+ Treg cells exhibited the opposite distribution. Furthermore, relative abundance of IL-10 and IL-10- Treg cells correlated with better and worse disease prognoses in human CRC, respectively. This functional dichotomy between Treg cell subsets provides a rationale for therapeutic strategies to selectively target pro-tumoral Treg cells while preserving their anti-tumoral counterparts across barrier tissue cancers that harbor both subsets.

immunology↗