Dendrobine ameliorates mitophagy-mediated endothelial senescence in diabetic kidney disease through activating the SIRT1/FOXO3a pathway

BACKGROUND: Glomerular senescence plays a vital role in the pathogenesis of diabetic kidney disease (DKD). Dendrobine (Den) exhibits anti-senescence properties and nephroprotective effects; however, its precise impact and underlying mechanisms in ameliorating glomerular senescence in DKD remain unclear. METHODS: The db/db mice were orally administered Den (10 and 30 mg/kg) for 8 weeks to evaluate its nephroprotective effect. Network pharmacology analysis was performed to investigate its underlying mechanisms. Senescence-associated β-galactosidase (SA-β-Gal) staining, Western blot, and RT-qPCR were employed to evaluate the beneficial effects of Den on inhibiting senescence in both in vivo and in vitro settings. The effects of Den on mitophagy were evaluated using transmission electron microscopy (TEM) and Western blot. RNA-seq was conducted to explore the molecular mechanisms underlying Den's amelioration of mitophagy-mediated endothelial senescence. siRNA and a pharmacological inhibitor of SIRT1 were utilized to validate the role of the SIRT1/FOXO3a pathway in this process. RESULTS: Biochemical and histological analyses indicated Den protected against renal injury in DKD mice. Network pharmacology analysis suggested Den's beneficial nephroprotective effects were associated with cellular senescence. SA-β-Gal staining showed that Den reduced the positive area of SA-β-Gal. Western blot and RT-qPCR results revealed that Den decreased the levels of senescence-associated proteins (p21 and p16) as well as secretory phenotype markers (IL-6, IL-8, IL-1β, MMP1, MMP3, and MMP10). Additionally, Den improved mitophagy levels, as evidenced by increased mitochondrial mean length and mitophagy-associated proteins (PINK1, Parkin, NIX, and BNIP3), along with a decreased proportion of damaged mitochondria. RNA-seq analysis indicated SIRT1 mRNA levels were significantly upregulated following Den treatment. Furthermore, siRNA-mediated knockdown of SIRT1 and Selisistat administration demonstrated that Den's inhibition of mitophagy-mediated endothelial senescence was associated with the activation of the SIRT1/FOXO3a pathway. CONCLUSIONS: These findings demonstrate that Den ameliorates endothelial senescence in DKD by enhancing mitophagy through activating the SIRT1/FOXO3a pathway, highlighting a promising therapeutic strategy for DKD patient.