PKM2-Mediated Metabolic Reprogramming Is Essential For Podocyte Differentiation And Function

Objections: Podocytes are the main component of the glomerular filtration barrier.The structural changes of podocytes play a key role in the development of various glomerular diseases.In recent years,more and more studies have shown that cell energy metabolism recombination is closely related to cellular function.It assumed that mitochondrial respiration is important for retaining podocyte differentiation and function,but a role for metabolic reprogramming in cell differentiation remains uncertain.Here,we demonstrate that PKM2 dimer and tetramer conversion plays a regulating role in podocyte energy metabolism.Methods: To induce differentiation,podocytes were grown at 37℃ for 10 days in the absence of interferon-g.The differentiation of podocyte were studied by Immunofluorescent for nephrin and flow cytometry for cell-cycle analysis.To quantificate ATP,Cells were exposed to vehicle or compound for 45 min before ATP assay was performed.Prolonged incubation of podocytes with TGF-b to examine tetramers,dimers and monomers of PKM2 by Cross-linking.Western blot and quantitative real-time PCR were performed to examine the expression level of glycolysis related enzymes.BALB/c mice were injected with ADR at the dosage of 10 mg/kg body weight in saline solution through tail vein to establish mouse model of podocyte injury and proteinuria.For activating PKM2 in vivo,schema of intervention-study design using ADR-induced podocyte injury treated with 50 mg/kg body weight TEPP-46 daily by oral gavage the day beforetail vein injection for one week.At one week after ADR injection,mice were sacrificed.Urine,kidney tissue,and glomeruli were collected.Results: During podocyte differentiation,the energy supply was gradually changed from aerobic glycolysis to mainly oxidative phosphorylation,and glycolysis also elevated during differentiation.Glucose metabolism was dominant in podocytes,In the key enzymes of glucose metabolism,the expression of PKM2 was upregulated obviously,especially the levels of the tetramer,and mitochondrial metabolism and biogenesis also increased significantly.With podocyte differentiation,PKM2 activation increased the biogenesis and fusion of mitochondria and promoted podocyte differentiation.podocytes exposed to TGF-? could be a shift in the distribution of PKM2 from dimmers to tetramers,resulting the transition from oxidative phosphorylation in differentiated podocytes to aerobic glycolysis in TGFβ-treated podocytes.Conversely,pharmacological activation of PKM2 by a small-molecule PKM2 activator,TEPP-46,reversed podocyte function,partially by increasing PGC-1a m RNA in vivo and vitro.Conclusions: Our findings demonstrate that PKM2 dimer and tetramer conversion plays a primary role in maintaining podocyte differentiation by regulating podocyte energy metabolism and provide the treatment with PKM2 activator as a potentially therapeutic strategy in podocyte injury.