Inhibition of GSK3B phosphorylation improves glucose and lipid metabolism disorder

Hepatic glycolipid metabolism disorder is considered as one of the key pathogenic factors for many chronic diseases. Revealing the molecular mechanism of metabolic disorder and exploring drug targets are crucial for the treatment of glucose and lipid metabolic diseases. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has been reported to be associated with the pathogenesis of various metabolic diseases. Herein, GAPDH-knockdown ZFL cells and GAPDH-downregulation zebrafish exhibited significant lipid deposition increase and glycogen reduction, thus inducing glucose and lipid metabolism disorders. Using high-sensitivity mass spectrometry-based proteomic and phosphoproteomic analysis, we identified 6838 proteins and 3738 phosphorylated proteins in GAPDH-knockdown ZFL cells. The protein-protein interaction network and DEPPs analyses showed that gsk3ba^Y216 were involved in lipid and glucose metabolism, which was verified by In vitro study. The enzyme activity analysis and cell staining results showed that HepG2 and NCTC-1469 cells transfected with GSK3B^Y216F plasmid had significantly lower glucose and insulin levels, the decreased lipid deposition, and the increased glycogen synthesis than those transfected with GSK3B^Y216E plasmid, suggesting that inhibition of GSK3B phosphorylation could significantly improve GSK3B hyperphosphorylation-induced glucose tolerance impairment and insulin sensitivity reduction. To our knowledge, this is the first multi-omic study of GAPDH-knockdown ZFL cells. This study provides insights into the molecular mechanism of glucose and lipid metabolic disorder, and provides potential targets (kinases) for the treatments of human glucose and lipid metabolic diseases.