Biology subjects

Nair, K. S.

Publications and source records attributed to Nair, K. S..

5 recordsLinked to original sources

bioRxiv2026

PRSS56 acts as an intrinsic retinal signal driving postnatal ocular axial growth and myopia susceptibility

Myopia is a leading cause of visual impairment worldwide, and high myopia markedly increases the risk of irreversible vision loss. Although visual experience guides postnatal ocular elongation, the role of intrinsic retinal growth signals remains poorly defined. Here we identify the serine protease PRSS56 as a retinal factor that promotes ocular axial growth beyond early development. Using genetic mouse models, we show that conditional inactivation of Prss56 in Muller glia reduces axial length and causes hyperopia even under dark-rearing conditions, demonstrating that PRSS56 drives axial elongation independently of light-evoked visual input during emmetropization. Conversely, Muller glia-specific overexpression of Prss56 induces axial elongation in a proteolysis-dependent manner, supporting its role as an autonomous retinal growth signal. In concordance, human genetic analyses reveal that the common PRSS56 variant rs2853447 is associated with increased axial length in individuals with myopia and high myopia, but not in non-myopes, suggesting that this variant confers a selective growth advantage in individuals predisposed to ocular elongation. Functional genomic analyses further identify a myopia-associated variant, rs2741297, within a retinal enhancer in intron 4 of PRSS56 marked by open chromatin and transcription factor occupancy. Together, these findings establish PRSS56 as an intrinsic retinal growth factor that functions beyond early eye development and support a model in which genetic and environmental factors converge on retinal pathways to modulate myopia susceptibility.

genetics↗

bioRxiv2025

MAVS Orchestrates a Potent IFN-independent Antiviral Immunity by Preserving Mitochondrial Integrity

Intrinsic antiviral defenses can restrict infection independent of paracrine interferon (IFN) signaling. While mitochondrial homeostasis is essential for immunity, its direct role in viral restriction remains incompletely understood. Here, we identify mitochondrial antiviral signaling protein (MAVS) as a central effector of a potent IFN-independent antiviral immunity orchestrated though mitochondrial safeguarding. We demonstrate that MAVS is critical for mitochondrial integrity as its loss leads to mitochondrial fragmentation, depolarization, and elevated mitophagy, alongside impaired bioenergetics and protein import. Mechanistically, MAVS maintains mitochondrial integrity by stabilizing the translocase of the outer membrane (TOM) complex and sustaining the abundance of its core components. Remarkably, this mitochondria-driven immunity restricts SARS-CoV-2 replication even under IFN-deficient conditions, and operates alongside the IFN pathways during JEV infection. Our findings redefine MAVS as a mitochondrial guardian that preserves organellar stability to enact host defense. These results highlight mitochondrial integrity as a fundamental determinant of broad antiviral immunity, integrating intrinsic and IFN-dependent mechanisms to counteract viral pathogenesis.

immunology↗

bioRxiv2022

Temporal dynamics of the multi-omic response to endurance exercise training across tissues

Regular exercise promotes whole-body health and prevents disease, yet the underlying molecular mechanisms throughout a whole organism are incompletely understood. Here, the Molecular Transducers of Physical Activity Consortium (MoTrPAC) profiled the temporal transcriptome, proteome, metabolome, lipidome, phosphoproteome, acetylproteome, ubiquitylproteome, epigenome, and immunome in whole blood, plasma, and 18 solid tissues in Rattus norvegicus over 8 weeks of endurance exercise training. The resulting data compendium encompasses 9466 assays across 19 tissues, 25 molecular platforms, and 4 training time points in young adult male and female rats. We identified thousands of shared and tissue- and sex-specific molecular alterations. Temporal multi-omic and multi-tissue analyses demonstrated distinct patterns of tissue remodeling, with widespread regulation of immune, metabolism, heat shock stress response, and mitochondrial pathways. These patterns provide biological insights into the adaptive responses to endurance training over time. For example, exercise training induced heart remodeling via altered activity of the Mef2 family of transcription factors and tyrosine kinases. Translational analyses revealed changes that are consistent with human endurance training data and negatively correlated with disease, including increased phospholipids and decreased triacylglycerols in the liver. Sex differences in training adaptation were widespread, including those in the brain, adrenal gland, lung, and adipose tissue. Integrative analyses generated novel hypotheses of disease relevance, including candidate mechanisms that link training adaptation to non-alcoholic fatty liver disease, inflammatory bowel disease, cardiovascular health, and tissue injury and recovery. The data and analysis results presented in this study will serve as valuable resources for the broader community and are provided in an easily accessible public repository (https://motrpac-data.org/). HighlightsO_LIMulti-tissue resource identifies 35,439 analytes regulated by endurance exercise training at 5% FDR across 211 combinations of tissues and molecular platforms. C_LIO_LIInterpretation of systemic and tissue-specific molecular adaptations produced hypotheses to help describe the health benefits induced by exercise. C_LIO_LIRobust sex-specific responses to endurance exercise training are observed across multiple organs at the molecular level. C_LIO_LIDeep multi-omic profiling of six tissues defines regulatory signals for tissue adaptation to endurance exercise training. C_LIO_LIAll data are available in a public repository, and processed data, analysis results, and code to reproduce major analyses are additionally available in convenient R packages. C_LI

molecular biology↗

bioRxiv2021

Tyr is Responsible for the Cctq1a QTL and Links Developmental Environment to Central Corneal Thickness Determination

Central corneal thickness is a quantitative trait with important associations to human health. In a phenotype-driven approach studying corneal thickness of congenic derivatives of C57BLKS/J and SJL/J mice, the critical region for a quantitative trait locus influencing corneal thickness, Cctq1a, was delimited to a 10-gene interval. Exome sequencing, RNAseq, and studying independent mutations eliminated multiple candidate genes and confirmed one. Though the causative gene, Tyr, has no obvious direct function in the transparent cornea, studies with multiple alleles on matched genetic backgrounds, both in isolation and genetic complementation crosses, confirmed allelism of Tyr-Cctq1a; albino mice lacking Tyr function had thin corneas. Albino mice also had increased axial length. Because albinism exposes eyes to increased light, the effect of dark-rearing was tested and found to rescue central corneal thickness. In sum, the results point to an epiphenomenon; developmental light exposure interacts with genotype as an important determinate of adult corneal thickness.

genetics↗

bioRxiv2018

PRSS56 is required for the developmental positioning of ocular angle structures

Angle-closure glaucoma (ACG) is a severe form of glaucoma affecting up to 16 million people worldwide. In ACG, physical blockage of the ocular drainage tissue by the peripheral iris impedes the drainage of aqueous humor resulting in elevated intraocular pressure (IOP) and subsequent optic nerve damage. Despite the high prevalence of ACG, the precise mechanism(s) underlying pathogenesis are only partially understood. We have previously demonstrated that a mutation in the gene encoding the serine protease PRSS56 causes an ACG phenotype in mice. Notably, Prss56 mutant mice exhibit a reduced ocular axial length and a lens occupying a larger ocular volume compared to WT mice, recapitulating characteristic features of human AGC. Our findings utilizing mouse genetic models demonstrate that loss of PRSS56 function results in altered configuration of ocular angle structures characterized by a posterior shift in the positioning of the ocular drainage tissue relative to the ciliary body and iris during development, leading to a physical blockage of drainage structure (angle closure) and high IOP. Utilizing a previously employed genetic strategy of rescuing mutant Prss56 mediated reduction in ocular size by inactivation of EGR1 (Egr1;Prss56 double mutants) we determined the influence of ocular size on developmental positioning of the ocular angle tissues. Our findings suggest that abnormal positioning of the drainage structure as a result of loss of PRSS56 function is uncoupled from its effect on ocular axial length reduction. Furthermore, we demonstrate that the IOP elevation observed in Prss56 mutant mice is genetic context-dependent and identify a dominant modifier locus on Chromosome 2 of the C3H/HeJ genome conferring susceptibility to high IOP. Overall, our findings reveal a novel role for PRSS56 in the proper configuration of the iridocorneal angle and provide new insight into the developmental pathways implicated in glaucoma pathogenesis.

genetics↗