The PKM2 activator TEPP-46 suppresses cellular senescence in hydrogen peroxide-induced proximal tubular cells and kidney fibrosis in CD-1db/db mice.

Abstract

Aim/introduction: Senescence is a key driver of age-related kidney dysfunction, including diabetic kidney disease. Oxidative stress activates cellular senescence, induces abnormal glycolysis, and is associated with pyruvate kinase muscle isoform 2 (PKM2) dysfunction; however, the mechanisms linking PK activation to cellular senescence have not been elucidated. We hypothesized that PKM2 activation by TEPP-46 could suppress oxidative stress-induced renal tubular cell injury and cellular senescence.

Materials and methods: To investigate the effects of PKM2 activation on oxidative stress-induced cellular senescence, we conducted β-galactosidase staining and western blot analysis on human primary renal tubular cells (pRPTECs) treated with hydrogen peroxide with or without TEPP-46. IL-6 levels and glycolytic flux were measured. Cell viability and apoptosis were assessed via the MTS assay and caspase 3 cleavage. For in vivo experiments, we utilized CD-1^db/db mice, a fibrotic type 2 diabetes model, which exhibit kidney fibrosis. After 4 weeks of TEPP-46 intervention, kidney fibrosis and the expression of senescence markers were analyzed.

Results: In pRPTECs, hydrogen peroxide increased the number of β-galactosidase-positive cells, the expression of senescence markers (p16, p21, p53), and p38 phosphorylation; co-incubation with TEPP-46 suppressed these alterations. Hydrogen peroxide reduced cell viability, induced apoptosis, mesenchymal alterations, and increased lactate production and IL-6 secretion; co-incubation with TEPP-46 or a p38 inhibitor mitigated these effects. In CD-1^db/db mice, TEPP-46 intervention suppressed apoptosis, fibrosis, and tended to reduce the levels of senescence-associated molecules in the kidney.

Conclusions: PKM2 activation could be a molecular target for protection against senescence-associated organ damage, including diabetic kidney disease.