miR-154-5p Affects the TGF beta 1/Smad3 Pathway on the Fibrosis of Diabetic Kidney Disease via Binding E3 Ubiquitin Ligase Smurf1

Aim. The study is aimed at verifying miR-154-5p and Smurf1 combination in glomerular mesangial cells regulating TGF beta 1/Smad3 pathway-related protein ubiquitination in the model of diabetic rats renal tissues, primary mesangial cells, and cell lines. Methods. The diabetic SD rat model and high-glucose-cultured primary mesangial cells and cell lines were established. miR-154-5p mimic and inhibitor, Smurf1 siRNA, and TGF beta 1/Smad3 inhibitor (SB431542) were pretreated to make the TGF beta 1/Smad3 pathway and ubiquitin changes. Fluorescence in situ hybridization was used for the miR-154-5p renal localization; molecular biological detection was adopted for cell proliferation, renal function, urine protein, and pathway proteins. After bioinformatics predicted binding sites, luciferase and Co-IP were used to detect miRNA and protein binding. Results. miR-154-5p was significantly increased and mainly concentrated in the glomerular of renal cortex in well-established diabetic rat renal tissues. Rno-miR-154-5p combined Rno-Smurf1 3 & PRIME; UTR, while Smurf1 combined Smad3 directly. Meanwhile, miR-154-5p regulates TGF beta 1/Smad3-mediated cell proliferation via Smurf1 ubiquitination. Conclusion. miR-154-5p regulates the TGF beta 1/Smads pathway through Smurf1 ubiquitination and promotes the fibrosis process of diabetic kidney disease.