Role of p53/miR-155-5p/sirt1 loop in renal tubular injury of diabetic kidney disease

Background: Diabetic kidney disease is a renal microvascular disease caused by diabetes, known as one of the most serious and lethal complications of diabetes Early renal hypertrophy is the main pathological feature, which gradually leads to the deposition of glomerular extracellular matrix and tubulointerstitial fibrosis, eventually developing irreversible structural damage to the kidneys Autophagy is a cell self-homeostatic mechanism that is activated under stress conditions and may serve as a protective response to the survival of renal fibrogenic cells MicroRNA (miRNA) network may be involved in the regulation of fibrosis The purpose of this study is to assess how miRNAs regulate diabetic kidney disease and autophagy and fibrosis in renal proximal tubular cells under high glucose conditions. Methods: Human renal proximal tubular (HK-2) cells were exposed to high glucose in vitro Bioinformatic analysis was used to select the candidate gene for potential target regulation of miR-155, Sirtl ATG5, ATG7 is the key to autophagosome formation, regulated by Sirtl p53 regulates miR-155 expression as a transcription factor MiR-155 overexpression and inhibition were achieved by transfection of miR-155 mimic and inhibit to evaluate its effect on Sirtl and autophagy and fibrosis markers Dual luciferase reporter assays were used to confirm the direct interaction of Sirtl withmiR-155 Overexpression and inhibition of Sirtl gene were achieved by transfection of Sirtl plasmid and Sirtl si to observe its effect on P53 Chip assay experiments confirmed the direct regulation of P53 on miR-155. Results: Under high glucose conditions, miR-155 was detected in HK-2 cells in concentration gradient, increased expression of p53 and down-regulated expression of sirtl and autophagy-associated proteins LC3II, ATG5 and ATG7 Dual luciferase reporter assays indicate that miR-155 can target its binding to the Sirtl 3'UTR region to reduce its expression Under high glucose conditions, over expression of miR-155 decreased the expression of LC3-II and ATG5 in HK-2 cells, while inhibition of miR-155 reversed this effect Using chip assay testing in HK-2 cells, we demonstrated that p53 binds directly to miR-155. Conclusions: The signaling axis of p53, miR-155-5p, and sirtl in autophagic process might be a critical adapting mechanism for diabetic kidney iniurv