Abstract
Diabetic nephropathy results from hyperglycemia‑mediated renal glomerular cell death via mitochondrial apoptosis. There is an emerging requirement for novel approaches with mitochondrial protective effects that alleviate the hyperglycemia‑induced loss of functional cells during diabetic renal damage. Liraglutide, a type of glucagon‑like peptide‑1 agonist, has been suggested to inhibit the progression of obesity and hyperglycemia. However, the contributions and mechanism of action of liraglutide on hyperglycemia‑mediated cell mitochondrial apoptosis in diabetic kidneys have not been illustrated. The present study demonstrated that liraglutide may protect human renal mesangial cells (HRMCs) against hyperglycemia‑induced cell death by inhibiting mitochondrial apoptosis. Liraglutide administration also maintained HRMC viability and promoted HRMC proliferation within a high glucose stress environment. Functional studies demonstrated that hyperglycemia triggered mitochondrial dysfunction, including mitochondrial potential reduction, mitochondrial permeability transition pore opening, reactive oxygen species overproduction and the activation of the mitochondrial apoptotic pathway. However, liraglutide treatment preserved mitochondrial function and prevented activation of mitochondrial apoptosis by upregulating sirtuin 3 (Sirt3) expression. Deletion of Sirt3 abrogated the protective effects of liraglutide on mitochondrial homeostasis following high glucose challenge. In addition, molecular analysis confirmed that liraglutide upregulated Sirt3 via activating the extracellular signal‑regulated kinase‑Yes‑associated protein (ERK‑Yap) signaling pathway. Inhibition of the ERK‑Yap axis negated the action of liraglutide on Sirt3 activation, leading to mitochondrial injury and HRMC apoptosis. Taken together, the present study illustrated that liraglutide protected renal mesangial cells from hyperglycemia‑mediated mitochondrial apoptosis by upregulating Sirt3 expression and activation of the ERK‑Yap signaling pathway.