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Sukhveer Singh

Publications and source records attributed to Sukhveer Singh.

2 recordsLinked to original sources
PubMed2026

Small extracellular vesicles are the key players in ochratoxin A-induced kidney toxicity.

BACKGROUND: Despite growing evidence of ochratoxin A (OTA)-induced kidney toxicity, the underlying mechanisms remain elusive. Emerging evidence suggests that small extracellular vesicles (sEVs) act as mediators of intercellular communication to recipient cells during various physiological and pathological conditions. Given the distinctive properties of sEVs, it is hypothesized that OTA-induced sEVs might mediate the OTA-induced kidney pathogenesis. METHODS: To explore the involvement of sEVs in OTA-induced kidney toxicity, sEVs were isolated and characterized from OTA-exposed rat kidney epithelial cells (NRK52E). Later, these sEVs were used to treat NRK52E cells and Wistar rats to assess the impact of OTA-induced sEVs on kidney toxicity. Label-free proteomics was also performed on OTA-induced sEVs, and key proteins were identified and validated. The biodistribution of sEVs in rats was also assessed using live imaging. The role of validated protein/s in kidney toxicity was further confirmed via a gene silencing and overexpression study. RESULTS: OTA exposure increased sEV secretion into conditioned media of NRK52E cells and into the urine of Wistar rats. Interestingly, we found that OTA-induced sEVs cause similar kidney toxicity in vitro and in vivo systems as OTA exposure, and blocking of sEV secretion markedly alleviated OTA-mediated kidney toxicity. Proteomics analysis identified annexin A2 and fibrinogen-ɣ as common proteins detected in sEVs derived from OTA-exposed NRK52E cells or rat urine. However, immunoblotting validated that annexin A2 was the only sEV-associated protein, expressed significantly in both NRK52E and rat urine following OTA exposure. Notably, silencing of annexin A2 attenuated the ability of OTA-induced sEVs to cause kidney toxicity, whereas overexpression exacerbates it. CONCLUSIONS: Our findings identify the annexin A2-enriched sEVs as key mediators of OTA-induced kidney toxicity. Annexin A2, along with other kidney injury markers, offers a promising non-invasive translational biomarker for early detection and monitoring of OTA-induced kidney toxicity.

Ochratoxins↗
PubMed2024

Prenatal arsenic exposure alters EZH2-H3K27me3 occupancy at TNF-α promoter leading to insulin resistance and metabolic syndrome in a mouse model.

The global prevalence of Metabolic Syndrome (MetS) is continuously rising and exposure to environmental toxicants such as arsenic could be contributing to this rapid surge. In this study, we have assessed the effects of prenatal arsenic exposure on insulin resistance and MetS parameters in a mouse model, and an underlying mechanism was identified. We found that prenatal arsenic exposure promotes insulin resistance and adipocyte dysfunction which leads to the early onset of MetS in male offspring. Primary adipocytes isolated from 20-week-old arsenic-exposed offspring showed hypertrophy, elevated basal lipolysis, and impaired insulin response along with enhanced expression of Tumor necrosis factor-alpha (TNF-α). TNF-α levels were consistently high at gestational day 15.5 (GD15.5) as well as primary adipocytes of 6-week-old arsenic-exposed male offspring. Along with TNF-α, downstream p-JNK1/2 levels were also increased, which led to inhibitory phosphorylation of IRS1and reduced GLUT4 translocation upon insulin stimulation in adipocytes. Insulin response and downstream signaling were restored upon TNF-α inhibition, confirming its central role. The persistent overexpression of TNF-α in adipocytes of arsenic-exposed mice resulted from diminished EZH2 occupancy and reduced H3K27me3 (gene silencing histone marks) at the TNF-α promoter. This further led to chromatin relaxation, recruitment of c-Jun and CBP/p300, formation of an enhanceosome complex, and TNF-α expression. Our findings show how prenatal arsenic exposure can epigenetically modulate TNF-α expression to promote adipocyte dysfunction and insulin resistance which contributes to the early onset of MetS in offspring.

Animals↗