Biology subjects

Rani, K.

Publications and source records attributed to Rani, K..

3 recordsLinked to original sources

bioRxiv2025

Stress-Induced Alteration of Small Extracellular Vesicles Drives Amyloid-Beta Sequestration and Exacerbates Alzheimer's Disease Pathogenesis

While small extracellular vesicles (sEVs) are implicated in amyloid-beta (A{beta}) trafficking, the mechanisms governing their interaction with A{beta} aggregates and plaque formation remain unresolved. Here, we report a paradigm-shifting discovery: sEVs undergo dynamic structural remodelling in response to stress, enabling selective binding to A{beta} aggregates-a phenomenon absent under normal physiological conditions. Using multimodal stressors, including mechanical (ultrasonication/agitation), physical (hyperthermia), and biological (oxidative damage), we demonstrate that stress-modified sEVs exhibit high-affinity binding to small A{beta} aggregates (SA) through scaffold reorganization, as validated by super-resolution microscopy and quantitative colocalization assays. Crucially, these remodelled sEVs act as potent carriers, enhancing SA internalization by neuronal cells in vitro. Strikingly, in post-mortem Alzheimers disease (AD) brains and APP-PS1 transgenic mice, sEVs were spatially enriched at amyloid plaque margins, suggesting a direct role in A{beta} sequestration and plaque expansion. Consistent with clinical relevance, sEVs isolated from AD patients exhibited an intrinsic SA-binding capacity, recapitulating stress-induced interactions observed experimentally. Our findings reveal that stress-primed sEVs function as pathological chaperones, binding to and internalizing A{beta} aggregates, thereby accelerating plaque nucleation and disease progression. This study provides the first evidence of stress-mediated sEV plasticity as a critical driver of A{beta} pathology, redefining therapeutic strategies targeting extracellular vesicle biology in neurodegenerative disorders. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=95 SRC="FIGDIR/small/655679v2_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@107c76borg.highwire.dtl.DTLVardef@1b56848org.highwire.dtl.DTLVardef@d18636org.highwire.dtl.DTLVardef@1c26db4_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2023

Plasmodium falciparum Raf kinase inhibitor is a lipid binding protein that interacts with CDPK1 and regulates its activity in asexual blood stage.

Raf Kinase Inhibitor Protein (RKIP) is an important regulator of MAPK signaling pathway in multicellular eukaryotes. Plasmodium falciparum RKIP (PfRKIP) is a putative phosphatidylethanolamine binding protein (PEBP) that shares limited similarity with Homo sapiens RKIP (HsRKIP). Interestingly, critical components of MAPK pathway are not expressed in malaria parasite and the physiological function of PfRKIP remains unknown. PfRKIP is expressed throughout the asexual schizogony with maximum expression in late schizonts. Interestingly, PfRKIP and HsRKIP show pH dependent differential interaction profiles with various lipids. At physiological pH, PfRKIP show interaction with PE and lipids containing phosphorylated phosphatidylinositol group; however, HsRKIP show no interaction under the same conditions. Mutation of conserved residues in the PEBP domain of PfRKIP decreases its interaction with PI(3)P. Furthermore, our results suggest that PfRKIP leads to increase in the autophosphorylation of PfCDPK1 that leads to transphosphorylation of substrates by PfCDPK1. Using various in vitro and in vivo experiments we have demonstrated the interaction of PfRKIP with PfCDPK1 and have also identified key residues in PfRKIP that play important role in this interaction. Interestingly, locostatin, a specific inhibitor of mammalian RKIP increased the interaction of PfRKIP with PfCDPK1 that perhaps leads to the sequestration of PfCDPK1 in a heterodimeric complex. Importantly, treatment of malaria parasite with locostatin shows dose dependent inhibition of parasite growth. This study suggests that specific inhibitors that modify PfRKIP leading to increase in its interaction with PfCDPK1 may be designed and explored as novel anti-malarial compounds to inhibit malaria parasite growth.

biochemistry↗

bioRxiv2020

Higher Order AMMI (HO-AMMI) analysis: A novel stability model to study genotype-location interactions

Additive main effects and multiplicative interaction (AMMI) model is most widely used to analyse genotype*environment interactions (GEI) wherein interaction effects of location is masked by year effect. Hence, presently available models are not able to estimate interaction effects of genotype*location (GLI) and genotype*year (GYI) separately. Moreover, genotype ranking differs as number of years of evaluation vary making selection of genotype for target location difficult. In the present study we propose a novel stability model i.e Higher-order-AMMI (HO-AMMI) analysis which is capable of calculating GLI without the confounding effect of GYI and GLYI. GEI of AMMI model and all 2-way interactions of HO-AMMI model follow {chi}2 distribution, whereas 3-way interaction (GLYI) of HO-AMMI follow noncentral {chi}2 distribution. With increase in number of years of evaluation contribution of GLI towards total variation increased whereas in AMMI model contribution of GEI towards total variation decreased. Variation explained by multiplicative components is higher in HO-AMMI compared to AMMI model. Genotypes were ranked using GL, GY and GL+GY+GLY interactions of HO-AMMI and GEI of AMMI for stability and yield and compared their ranks with field ranking. Correlation and linear regression analysis have indicated high association of GLI (HO-AMMI) with field ranking with high R2 values. Further, HO-AMMI model was able to remove the confounding effect of GYI and GLYI on GLI for accurate identification of genotype for target location irrespective of number of years of evaluation. Hence, HO-AMMI model can be used under multi-environment trials (MET) for selecting genotypes efficiently. Availability and InformationSource code implemented in R is available from corresponding author.

plant biology↗