Biology subjects

Gopal, R.

Publications and source records attributed to Gopal, R..

13 recordsLinked to original sources

bioRxiv2026

Iron sensing modules participate in rhizospheric pH perception in rice

Rhizospheric pH has emerged as one of the most important environmental factors regulating plant fitness in almost every aspect of plant physiology and development. Interestingly, the information on how plant perceive rhizospheric pH is still not well understood. In this report we have elucidated the intricate mechanism where rhizospheric pH mediated changes in relative Fe availability are sensed by the plants to initiate complex physiological responses. Using root specific RNA-seq, ICPMS, hormone quantification and physiological validation in rice, the study revealed Fe availability to be a critical determinant of rhizospheric pH where the relative Fe toxicity towards acidic pH and Fe deficiency towards alkaline pH is deduced by the plant in the form of JA-auxin crosstalk regulating the physiological responses against rhizospheric pH.

plant biology↗

bioRxiv2026

Genome-Wide Transcriptomics Uncovers a Lung-to-Aorta Inflammatory Program Driving Influenza-Induced Atherosclerosis Exacerbation

Influenza infection increases cardiovascular risk in individuals with pre-existing atherosclerosis, yet the genome-wide transcriptional basis of this association remains undefined. We performed bulk RNA sequencing of aorta and lung tissues from high-fat diet-fed Apoe-/- mice infected with influenza A/PR/8/34 versus PBS-treated controls at day 15 post-infection, identifying 6,828 differentially expressed genes across both tissues (5,694 in the lung and 1,134 in the aorta; adjusted p < 0.05). In the lung, influenza sustained a CXCR3-driven chemokine storm, comprehensive Th1, Th17, and exhaustion T-cell activation programs, coordinated monocyte recruitment through Ccl2, Ccl7, Ccl8, and Ccl12, a broad acute phase response including Saa3 and A2m, alveolar identity collapse through loss of Nkx2-1 and surfactant proteins, and broad metabolic dysregulation involving suppression of fatty acid oxidation, mitochondrial function, and circadian metabolic regulators. In the aorta, influenza drove macrophage and DAMP activation through Trem1, Fpr2, and S100a8, cytotoxic T-cell engagement, smooth muscle cell dedifferentiation through Myocd loss, convergent bioenergetic failure, and an ectopic lung-identity gene signature representing a previously undescribed cross-organ communication mechanism. Circadian clock and Hippo/YAP pathway suppression were shared across both tissues, identifying systemic vulnerabilities connecting pulmonary infection to vascular structural compromise. Consistent with the in vivo findings, influenza-infected Apoe-/- bone marrow-derived macrophages exhibited inflammasome activation, DAMP amplification, M1 polarization, and suppression of prostaglandin-mediated inflammatory resolution. Together these findings define a lung-to-aorta inflammatory and metabolic axis driving atherosclerotic plaque destabilization during the post-infection recovery period and identify CCR2/CXCR3 antagonism, NLRP3 inhibition, and YAP pathway activation as candidate therapeutic interventions.

immunology↗

bioRxiv2026

The effect of an ultrasound-activated electrospun piezoelectric hydrogel scaffold on post-traumatic brain injury motor function in Drosophila melanogaster

Traumatic brain injury (TBI) is a leading cause of long-term neurological disability, affecting 50-60 million people annually. Cascading secondary injury mechanisms, including oxidative stress and neuroinflammation, impair motor and cognitive function, while current therapies often manage symptoms rather than restore lost neurological function. This study investigated an ultrasound-activated piezoelectric hydrogel scaffold composed of barium titanate nanoparticles (BTNPs), sodium alginate (SA), and polyethylene oxide (PEO). The hypothesis was that TBI flies receiving the scaffold and ultrasound would display a higher climbing assay pass rate than TBI flies receiving no treatment or BTNPs alone. TBI was induced in Drosophila melanogaster with a high-impact trauma (HIT) apparatus. Treatments were applied by opening and resealing the fly head cuticle, followed by ultrasound stimulation. Motor recovery was quantified with a climbing assay across four groups (N=10 flies per group), which measured the percentage of flies that could cross a 5 cm mark within 30 seconds. Assay validity was supported by a statistically significant difference between flies without TBI and those with TBI using Mann-Whitney U testing (p=0.0035). Although TBI treatment groups did not differ significantly (p>0.05), median pass rates increased from injury control (35%) to BTNPs (45%) to scaffold (50%). However, high inter-trial variation, a 45.2% procedural mortality rate, and small sample size limited statistical power. These results suggest that piezoelectric electrospun hydrogel scaffolds may be a pathway for safer and more biocompatible restoration after TBI, but provide insufficient evidence to conclude that the scaffold significantly improved motor recovery.

neuroscience↗

bioRxiv2026

IL-27 Signaling Protects Against Influenza-Associated Pulmonary Aspergillosis Through Inhibition of Type 2 Immunity and Enhanced Antifungal Immunity

Influenza-associated pulmonary aspergillosis (IAPA) is a severe complication of influenza infection associated with substantial mortality. Influenza disrupts pulmonary host defenses and alters innate immune responses, predisposing patients to invasive fungal infection. Interleukin-27 (IL-27) is an immunoregulatory cytokine with context-dependent antiviral and antifungal effects; however, its role during IAPA remains undefined. A mouse model of IAPA was established by infecting wild-type and IL-27 receptor -deficient (Il27ra-/-) mice with influenza A, followed by Aspergillus fumigatus challenge. IL-27 and IL-27R expression were increased during IAPA. Single-cell RNA sequencing identified monocytes as the primary source of IL-27 and T cells as major IL-27r-expressing cells. Il27ra-/- mice exhibited significantly increased pulmonary fungal and influenza viral burden, enhanced type 2 immune responses characterized by elevated IL-4, IL-5, IL-9, IL-13, eosinophils, Th2 cells, pathogenic Th2 cells, and ILC2s. Despite increased eosinophil abundance, eosinophil-mediated conidial killing was impaired in Il27ra-/- mice. IL-27R deficiency also reduced macrophage abundance and impaired macrophage conidial uptake. Conversely, timed administration of rIL-27 enhanced fungal clearance, improved survival, and increased macrophage conidial uptake and augmented eosinophil killing capacity during IAPA. IL-27 signaling is a protective immunoregulatory cytokine during IAPA that limits pathological type 2 inflammation and enhances antifungal effector function of both eosinophils and macrophages. These findings identify IL-27 as a potential therapeutic in IAPA.

immunology↗

bioRxiv2026

Broad remodeling of the pulmonary immune landscape occurs during IAPA with specific functional deficits of neutrophil subsets

BackgroundInfluenza-associated pulmonary aspergillosis (IAPA) is a severe complication of influenza infection associated with prolonged intensive care unit stay and increased mortality. Although impaired antifungal immunity has been implicated in IAPA pathogenesis, the cell type-specific immune mechanisms driving susceptibility remain incompletely understood. We aimed to characterize the pulmonary immune landscape during IAPA using single-cell transcriptomics and functional neutrophil assays. MethodsMale C57BL/6 mice were assigned to naive control, influenza A/PR/8/34 (H1N1) infection, A. fumigatus (ATCC 42202) infection, or IAPA groups. Lung CD45+ immune cells underwent single-cell RNA sequencing with downstream clustering and CellChat ligand-receptor interaction analysis. Differential gene expression analyses were performed across myeloid, lymphoid, and neutrophil populations. Functional neutrophil responses were evaluated using flow cytometry, myeloperoxidase activity assays, and FLARE (fluorescent Aspergillus reporter) conidia to assess fungal conidia uptake and killing. Cross-species validation was performed using gene set enrichment analysis compared with published human IAPA transcriptomic datasets. ResultsIAPA broadly remodeled the pulmonary immune landscape across myeloid, lymphoid, and neutrophil compartments. Myeloid cells showed coordinated suppression of fungal pattern recognition receptors, lysosomal biogenesis programs, and inflammatory signaling. Lymphoid populations exhibited transcriptional signatures of T cell exhaustion and Th17 suppression. Within the neutrophil compartment, we identified two transcriptionally and functionally distinct populations, conventional and inflammatory neutrophils, with divergent antifungal effector capacities. Inflammatory neutrophils showed selective killing defects, while both subsets exhibited impaired phagocytic uptake during IAPA. Murine transcriptomic findings demonstrated strong concordance with immune dysfunction signatures identified in human IAPA. ConclusionIAPA susceptibility arises from coordinated transcriptional dysfunction spanning innate and adaptive immune compartments. Distinct neutrophil subset dysfunction, impaired fungal recognition pathways, and T-cell exhaustion signatures collectively contribute to defective fungal clearance, providing mechanistic insight into IAPA susceptibility and potential therapeutic targets.

immunology↗

bioRxiv2024

The population structure of invasive Lantana camara is shaped by its mating system

Over the last century, invasive species have emerged as an important driver of global biodiversity loss. Many invasive species have low genetic diversity in the invaded habitats, owing to the demographic bottleneck during introduction. Lantana camara is one of the hundred most problematic invasive species globally. Despite its ecological importance in many countries, our understanding of the genetic diversity patterns of this plant remains poor. Previous studies hypothesize that invasive L. camara is a species complex with a hybrid origin, though this has never been tested. We investigated the population genetic patterns of L. camara by sampling 359 plants that represented a spectrum of flower colour variants across 36 locations, spanning most of the biogeographic regions across India. Analyses of the population structure using 19,008 SNPs revealed that L. camara in India exhibits a strong genetic structure. Interestingly, the structuring pattern does not exhibit a strong correlation with geography. In the structure analysis, individuals with similar flower colours clustered together regardless of their location of origin. The genetic distance between most of the individuals was low, indicating the absence of multiple species. A high inbreeding coefficient and a low proportion of heterozygous sites observed suggested that the strong structure could be due to self-fertilization. This was further confirmed by bagging experiments, which demonstrated that L. camara is self-compatible in India. Thus, we infer that L. camara exists as homozygous inbred lines formed by self-fertilization and that these inbred lines could be associated with distinct flower colours. Together, this would explain the correlation between flower colour and genetic structure, and the lack of geographic structure. These results refute the argument that L. camara is a species complex and emphasize the importance of the mating system in shaping the patterns of diversity in this invasive species. Our findings highlight a hitherto unknown role for mating systems in invasive species, furthering our understanding of evolution in invasive species.

evolutionary biology↗

bioRxiv2024

T cell epitope mapping reveals immunodominance of evolutionarily conserved regions within SARS-CoV-2 proteome.

As SARS-CoV-2 variants continue to emerge capable of evading neutralizing antibodies, it has become increasingly important to fully understand the breadth and functional profile of T cell responses to determine their impact on the immune surveillance of variant strains. Here, sampling healthy individuals, we profiled the kinetics and polyfunctionality of T cell immunity elicited by mRNA vaccination. Modeling of anti-spike T cell responses against ancestral and variant strains of SARS-CoV-2 suggested that epitope immunodominance and cross-reactivity are major predictive determinants of T cell immunity. To identify immunodominant epitopes across the viral proteome, we generated a comprehensive map of CD4+ and CD8+ T cell epitopes within non-spike proteins that induced polyfunctional T cell responses in convalescent patients. We found that immunodominant epitopes mainly resided within regions that were minimally disrupted by mutations in emerging variants. Conservation analysis across historical human coronaviruses combined with in silico alanine scanning mutagenesis of non-spike proteins underscored the functional importance of mutationally-constrained immunodominant regions. Collectively, these findings identify immunodominant T cell epitopes across the mutationally-constrained SARS-CoV-2 proteome, potentially providing immune surveillance against emerging variants, and inform the design of next-generation vaccines targeting antigens throughout SARS-CoV-2 proteome for broader and more durable protection. One Sentence SummaryPolyfunctional CD8+ and CD4+ T cells directed against SARS-CoV-2 target mutationally constrained regions of the viral proteome.

immunology↗

bioRxiv2023

Single-cell RNA sequencing identifies SLC6A3 as a biomarker and prognostic marker in clear cell renal cell carcinoma

BackgroundThe SLC6A3 gene encodes dopamine protein and is a member of the sodium and chloride-dependent neurotransmitter transporter family. While the role of SLC6A3 in Parkinsons disease is well established, its function in cancer, especially in clear cell renal cell carcinoma (ccRCC), remains unclear. MethodsTo investigate the expression and function of SLC6A3 in ccRCC, we conducted a study using single-cell transcriptomics and bulk RNA sequencing data. We analyzed advanced ccRCC single-cell RNA sequencing profiles, bulk RNA sequencing, and microarray data to assess the expression of SLC6A3 in tumor cells, benign kidney tubule cells, and immune cells. ResultsOur analysis showed that SLC6A3 expression is specific to ccRCC tumor cells and is not present in benign kidney tubule cells or immune cells of benign kidney and kidney tumors. Further, we found an elevated expression of SLC6A3 in ccRCC tumors compared to the benign kidney. Receiver operating characteristics analysis suggests that SLC6A3 is highly sensitive and specific to ccRCC. Additionally, we found a correlation between HNF4A signaling and SLC6A3 expression in two independent mRNA expression profiles. Interestingly, elevated expression of SLC6A3 is a predictor of better overall and progression-free survival of ccRCC patients. ConclusionsOur findings suggest that SLC6A3 is a potential diagnostic and prognostic marker for ccRCC. The study highlights the importance of understanding the role of SLC6A3 in cancer and provides new insights into ccRCC diagnosis and treatment.

cancer biology↗

bioRxiv2023

Machine Learning-Guided Antibody Engineering That Leverages Domain Knowledge To Overcome The Small Data Problem

The application of Machine Learning (ML) tools to engineer novel antibodies having predictable functional properties is gaining prominence. Herein, we present a platform that employs an ML-guided optimization of the complementarity-determining region (CDR) together with a CDR framework (FR) shuffling method to engineer affinity-enhanced and clinically developable monoclonal antibodies (mAbs) from a limited experimental screen space (order of 10^2 designs) using only two experimental iterations. Although high-complexity deep learning models like graph neural networks (GNNs) and large language models (LLMs) have shown success on protein folding with large dataset sizes, the small and biased nature of the publicly available antibody-antigen interaction datasets is not sufficient to capture the diversity of mutations virtually screened using these models in an affinity enhancement campaign. To address this key gap, we introduced inductive biases learned from extensive domain knowledge on protein-protein interactions through feature engineering and selected model hyper parameters to reduce overfitting of the limited interaction datasets. Notably we show that this platform performs better than GNNs and LLMs on an in-house validation dataset that is enriched in diverse CDR mutations that go beyond alanine-scanning. To illustrate the broad applicability of this platform, we successfully solved a challenging problem of redesigning two different anti-SARS-COV-2 mAbs to enhance affinity (up to 2 orders of magnitude) and neutralizing potency against the dynamically evolving SARS-COV-2 Omicron variants.

bioengineering↗

bioRxiv2022

Biologically relevant integration of transcriptomics profiles from cancer cell lines, patient-derived xenografts and clinical tumors using deep neural networks

Cell lines and patient-derived xenografts are essential to cancer research, however, the results derived from such models often lack clinical translatability, as these models do not fully recapitulate the complex cancer biology. It is critically important to better understand the systematic differences between cell lines, xenografts and clinical tumors, and to be able to identify pre-clinical models that sufficiently resemble the biological characteristics of clinical tumors across different cancers. On another side, direct comparison of transcriptional profiles from pre-clinical models and clinical tumors is infeasible due to the mixture of technical artifacts and inherent biological signals. To address these challenges, we developed MOBER, Multi-Origin Batch Effect Remover method, to simultaneously extract biologically meaningful embeddings and remove batch effects from transcriptomic datasets of different origin. MOBER consists of two neural networks: conditional variational autoencoder and source discriminator neural network that is trained in adversarial fashion. We applied MOBER on transcriptional profiles from 932 cancer cell lines, 434 patient-derived tumor xenografts and 11159 clinical tumors and identified pre-clinical models with greatest transcriptional fidelity to clinical tumors, and models that are transcriptionally unrepresentative of their respective clinical tumors. MOBER can conserve the biological signals from the original datasets, while generating embeddings that do not encode confounder information. In addition, it allows for transformation of transcriptional profiles of pre-clinical models to resemble the ones of clinical tumors, and therefore can be used to improve the clinical translation of insights gained from pre-clinical models. As a batch effect removal method, MOBER can be applied widely to transcriptomics datasets of different origin, allowing for integration of multiple datasets simultaneously.

bioinformatics↗

bioRxiv2021

SARS-CoV-2-specific memory B cells can persist in the elderly despite loss of neutralising antibodies

Memory B cells (MBC) can provide a recall response able to supplement waning antibodies with an affinity-matured response better able to neutralise variant viruses. We studied a cohort of vulnerable elderly care home residents and younger staff, a high proportion of whom had lost neutralising antibodies (nAb), to investigate their reserve immunity from SARS-CoV-2-specific MBC. Class-switched spike and RBD-tetramer-binding MBC with a classical phenotype persisted five months post-mild/asymptomatic SARS-CoV-2 infection, irrespective of age. Spike/RBD-specific MBC remained detectable in the majority who had lost nAb, although at lower frequencies and with a reduced IgG/IgA isotype ratio. Functional spike/S1/RBD-specific recall was also detectable by ELISpot in some who had lost nAb, but was significantly impaired in the elderly, particularly to RBD. Our findings demonstrate persistence of SARS-CoV-2-specific MBC beyond loss of nAb, but highlight the need for careful monitoring of functional defects in RBD-specific B cell immunity in the elderly. One sentence summaryCirculating class-switched spike and RBD-specific memory B cells can outlast detectable neutralising antibodies but are functionally constrained in the elderly.

immunology↗

bioRxiv2019

Y-RNAs Lead an Endogenous Program of RIG-I Agonism Mobilized upon RNA Virus Infection and Targeted by HIV

Pattern recognition receptors (PRRs) protect against host invasion by detecting specific molecular patterns found in pathogens and initiating an immune response. While microbial-derived PRR ligands have been extensively characterized, the contribution and relevance of endogenous ligands to PRR activation during viral infection remain overlooked. In this work, we characterize the landscape of endogenous ligands that engage RIG-I-like receptors (RLRs) upon infection by a positive-sense RNA virus, a negative-sense RNA virus or a retrovirus. We found that several endogenous RNAs transcribed by RNA polymerase 3 (Pol3) specifically engage RLRs, and in particular the family of small non-coding repeats Y-RNAs, which presents the highest affinity as RIG-I ligands. We show that this recognition is dependent on Y-RNA mimicking viral secondary structure and its 5-triphosphate extremity. Further, we found that HIV-1 infection triggers a VPR-dependent downregulation of RNA triphosphatase DUSP11 in vitro and in vivo, leading to an increase of Y-RNA 5-triphosphorylation that enables their immunogenicity. Importantly, we show that altering DUSP11 expression is sufficient to induce a type-I interferon and T cell activation transcriptional program associated with HIV-1 infection. Overall, our work uncovers the critical contribution of endogenous repeat RNAs ligands to antiviral immunity and demonstrates the role of this pathway in HIV-1 infection.

immunology↗

bioRxiv2018

P2X antagonists inhibit HIV-1 productive infection and inflammatory cytokines IL-10 and IL-1β in a human tonsil explant model

HIV-1 causes a persistent infection of the immune system that is associated with chronic comorbidities. The mechanisms that underlie this inflammation are poorly understood. Emerging literature has implicated pro-inflammatory purinergic receptors and downstream signaling mediators in HIV-1 infection. This study probed whether inhibitors of purinergic receptors would reduce HIV-1 infection and HIV-1 stimulated inflammation. A human ex vivo human tonsil histo-culture infection model was developed to support HIV-1 productive infection and stimulated inflammatory cytokine interleukin-1 beta (IL-1{beta}) and immunosuppressive cytokine, interleukin-10 (IL-10). This study tests whether inhibitors of purinergic receptors would reduce HIV-1 infection and HIV-1 stimulated inflammation. The purinergic P2X1 receptor antagonist, NF449, the purinergic P2X7 receptor antagonists, A438079, and azidothymidine (AZT) were tested in HIV-1 infected human tonsil explants to compare inhibition of HIV-1 infection and HIV-stimulated inflammatory cytokine production. All drugs limited HIV-1 productive infection but P2X-selective antagonists (NF449, and A438079) significantly lowered HIV-stimulated IL-10 and IL-1{beta}. We further observed that P2X1- and P2X7-selective antagonists can act differentially as inhibitors of both HIV-1 infection and HIV-1-stimulated inflammation. Our findings highlight the differential effects of HIV-1 on inflammation in peripheral blood as compared to lymphoid tissue. For the first time, we demonstrate that P2X-selective antagonists act differentially as inhibitors of both HIV-1 infection and HIV-1-stimulated inflammation. Drugs that block these pathways can have independent inhibitory activities against HIV-1 infection and HIV-induced inflammation.\n\nImportancePatients who are chronically infected with HIV-1 experience sequelae related to chronic inflammation. The mechanisms of this inflammation have not been elucidated. Here we describe a class of drugs that target the P2X pro-inflammatory signaling receptors in a human tonsil explant model. This model highlights differences in HIV-1 stimulation of lymphoid tissue inflammation and peripheral blood. These drugs serve to both block HIV-1 infection and production of IL-10 and IL-1{beta} in lymphoid tissue suggesting a novel approach to HIV-1 therapeutics in which both HIV-1 replication and inflammatory signaling are simultaneously targeted.

immunology↗