Un modèle in vitro de sénescence rénale induite par le stress oxydant pour étudier le vieillissement et le métabolisme

Chronic kidney disease (CKD) is a major public health issue affecting more than 10% of the global population. CKD is characterised by a progressive and irreversible loss of renal functions. Growing evidence suggests that cellular senescence plays a crucial role in the pathogenesis of CKD, notably through the senescence-associated secretory phenotype (SASP). In the kidneys, senescence-associated alterations affect mostly proximal tubular epithelial cells (PTEC). At the cellular level, senescence leads to metabolic alterations and to disturbances in lipid metabolism. However, limited information exists to explain the molecular mechanisms underlying these disturbances in renal senescent cells. Therefore, this study aimed to develop a reliable and reproducible in vitro model of PTEC senescence to investigate the emerging roles of senescence in the kidney. Here, we developed a model of renal senescence in PTEC by exposing human PTEC (HK-2 cell line) to 300 and 500 µM of hydrogen peroxide (H2O2) for two hours. Three and five days after exposure to H2O2, HK-2 cells displayed typical morphology of senescent cells, notably enlarged cell and nuclear sizes. They also exhibited well-known senescence features such as senescence-associated β-galactosidase (SA-β-gal)- and γH2AX-staining, overexpression of IL6, IL8 and CDKN1A genes, cell cycle arrest and decreased expression of LMNB1 gene. Interestingly, disturbances in lipid metabolism were also measured, as evidenced by a massive lipid droplet accumulation in senescent cells. In conclusion, these results show that this robust senescent cell model can be used to study tubular senescence and the underlying alterations in the kidney.