Branched-chain amino acids contribute to diabetic kidney disease progression via PKM2-mediated podocyte metabolic reprogramming and apoptosis.

Summary

BCAA catabolic defects in podocytes are identified as a trigger for DKD, acting through PKM2 depolymerization to reprogram metabolism and drive apoptosis. Genetic and nutritional perturbations reproduce DKD phenotypes, nominating BCAA catabolism and PKM2 activation as preventive or therapeutic targets.

Key Findings

• Podocytes in human DKD and db/db mice show specific defects in BCAA catabolism.
• Podocyte PP2Cm knockout or exogenous BCAA supplementation induces DKD phenotypes (podocyte dysfunction/apoptosis, glomerular lesions, proteinuria) in HF-fed mice.
• BCAAs promote PKM2 depolymerization, shifting metabolism away from OXPHOS towards serine/folate pathways and, via nuclear PKM2-DDIT3, upregulate Chac1 and Trib3 to trigger apoptosis.

Clinical Implications

Supports caution with high-BCAA supplementation in diabetes and prioritizes development of PKM2 activators or strategies to restore BCAA catabolism as DKD-modifying therapies.

Limitations

• Clinical translatability (dose-response, safety) of PKM2 activation or BCAA manipulation remains untested in humans.
• Quantitative human sample size and covariate adjustment details are not provided.

Future Directions

Develop PKM2 activators and BCAA-catabolism–restoring strategies; test dietary BCAA modulation in controlled clinical studies; validate podocyte metabolic signatures as DKD biomarkers.