Biology subjects

Rao, S. P.

Publications and source records attributed to Rao, S. P..

4 recordsLinked to original sources

bioRxiv2025

Oral prodrug of a novel glutathione surrogate reverses metabolic dysregulation and attenuates neurodegenerative process in APP/PS1 mice

Glycation-induced oxidative stress underlies the numerous metabolic ravages of Alzheimers disease (AD). Reduced glutathione levels in AD lead to increased oxidative stress, including glycation-induced pathology. Previously, we showed that the accumulation of reactive 1,2-dicarbonyls such as methylglyoxal, the major precursor of non-enzymatic glycation products, was reduced by the increased function of GSH-dependent glyoxalase-1 enzyme in the brain. In this two-pronged study, we evaluate the therapeutic efficacy of an orally bioavailable prodrug of our lead glyoxalase substrate, pro-{psi}-GSH, for the first time in a transgenic Alzheimers disease mouse model. This prodrug delivers pharmacodynamically relevant brain concentrations of {psi}-GSH upon oral delivery. Chronic oral dosing of pro-{psi}-GSH effectively reverses the cognitive decline observed in the APP/PS1 mouse model. The prodrug successfully mirrors the robust effects of the parent drug i.e., reducing amyloid pathology, glycation stress, neuroinflammation, and the resultant neurodegeneration in these mice. We also report the first metabolomics study of such a treatment, which yields key biomarkers linked to the reversal of AD-related metabolic dysregulation. Collectively, this study establishes pro-{psi}-GSH as a viable, disease-modifying therapy for AD and paves the way for further preclinical advancement of such therapeutics. Metabolomic signatures identified could prove beneficial in the development of treatment-specific clinically translatable biomarkers. ABSTRACT GRAPHIC O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=196 SRC="FIGDIR/small/633247v1_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@a9c2c0org.highwire.dtl.DTLVardef@130ed71org.highwire.dtl.DTLVardef@134a19corg.highwire.dtl.DTLVardef@5e0f89_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

Unveiling inverted D genes and D-D fusions in human antibody repertoires unlocks novel antibody diversity

Antibodies, fundamental to immune defense, derive their diversity primarily from the intricate rearrangement of variable (V), diversity (D), and joining (J) gene segments. Traditionally, D genes in the forward (5-3) direction contribute to this diversity by rearranging with V and J segments. However, the existence and significance of inverted D genes (InvDs), which are D genes oriented in the inverted (3-5) direction, were previously obscured by limitations in data and detection methods. Here, we carried out a comprehensive analysis of a large-scale public next-generation sequencing (NGS) dataset encompassing antibody repertoires from 13 healthy donors using a novel immunoinformatics workflow. Our analysis, for the first time, uncovers the existence of all 25 unique InvDs across all three reading frames within human antibody repertoires, including both naive and memory B cells. This finding challenges previous assumptions, revealing the extensive presence of InvDs and identifying a broad spectrum of D-D fusions, especially those involving InvDs. Notably, InvDs enrich for unique amino acids such as histidine, proline, and lysine, not commonly found in forward D genes, and exhibit reduced use of certain negatively charged and bulky amino acids, including aspartate, tryptophan, and methionine. The unique amino acid profile of InvDs discloses new diversity and functionality in the human antibody repertoire, evidenced by over two dozen documented antibodies featuring InvDs, targeting a wide array of antigens. By opening exciting avenues for immunogenetics research, including new chromatin compaction models, innovative antibody libraries, and advancements in antibody engineering, these findings hold promise for the development of novel therapeutics and vaccines.

immunology↗

bioRxiv2023

Deletion of Glyoxalase 1 exacerbates acetaminophen-induced hepatotoxicity in mice

Acetaminophen (APAP) overdose triggers a cascade of intracellular oxidative stress events culminating in acute liver injury. The clinically used antidote, N-acetylcysteine (NAC) has a narrow therapeutic window and early treatment is essential for satisfactory therapeutic outcome. For more versatile therapies that can be effective even at late-presentation, the intricacies of APAP-induced hepatotoxicity must be better understood. Accumulation of advanced glycation end-products (AGEs) and consequent activation of the receptor for AGEs (RAGE) are considered one of the key mechanistic features of APAP toxicity. Glyoxalase-1 (Glo-1) regulates AGE formation by limiting the levels of methylglyoxal (MEG). In this study, we studied the relevance of Glo-1 in APAP mediated activation of RAGE and downstream cell-death cascades. Constitutive Glo-1 knockout mice (GKO) and a cofactor of Glo-1, {psi}-GSH, were employed as tools. Our findings show elevated oxidative stress, activation of RAGE and hepatocyte necrosis through steatosis in GKO mice treated with high-dose APAP compared to wild type controls. A unique feature of the hepatic necrosis in GKO mice is the appearance of microvesicular steatosis as a result of centrilobular necrosis, rather than inflammation seen in wild type. The GSH surrogate and general antioxidant, {psi}-GSH alleviated APAP toxicity irrespective of Glo-1 status, suggesting that oxidative stress being the primary driver of APAP toxicity. Overall, exacerbation of APAP hepatotoxicity in GKO mice suggests the importance of this enzyme system in antioxidant defense against initial stages of APAP overdose.

pharmacology and toxicology↗

bioRxiv2020

Developmental Expression of Transforming Growth Factor Induced Protein Promotes NF-Kappa-B Mediated Angiogenesis During Postnatal Lung Development

RationalePulmonary angiogenesis is a key driver of alveolarization. Our prior studies showed that nuclear factor kappa-B (NF{kappa}B) promotes pulmonary angiogenesis during early alveolarization. However, the mechanisms regulating temporal-specific NF{kappa}B activation in the pulmonary vasculature are unknown. ObjectivesTo identify mechanisms that activate pro-angiogenic NF{kappa}B signaling in the developing pulmonary vasculature. MethodsProteomic analysis of the lung secretome was performed using 2D-DIGE. NF{kappa}B activation and angiogenic function was assessed in primary pulmonary endothelial cells (PEC) and TGFBI-regulated genes identified using RNA-sequencing. Alveolarization and pulmonary angiogenesis was assessed in WT and TGFBI null mice exposed to normoxia or hyperoxia. Lung TGFBI expression was determined in premature lambs supported by invasive and noninvasive respiratory support. Measurements and Main ResultsSecreted factors from the early alveolar, but not the late alveolar or adult lung, promoted proliferation and migration in quiescent, adult PEC. Proteomic analysis identified transforming growth factor beta-induced protein (TGFBI) as a protein highly expressed by myofibroblasts in the early alveolar lung that promoted PEC migration by activating NF{kappa}B via v{beta}3 integrins. RNA-sequencing identified Csf3 as a TGFBI-regulated gene that enhances nitric oxide production in PEC. Loss of TGFBI in mice exaggerated the impaired pulmonary angiogenesis induced by chronic hyperoxia, and TGFBI expression was disrupted in premature lambs with impaired alveolarization. ConclusionsOur studies identify TGFBI as a developmentally-regulated protein that promotes NF{kappa}B-mediated angiogenesis during early alveolarization by enhancing nitric oxide production. We speculate that dysregulation of TGFBI expression may contribute to diseases marked by impaired alveolar and vascular growth.

developmental biology↗