Several protein tyrosine phosphatases (PTPs) that disrupt the insulin-signaling pathway were investigated by siRNAs to identify potential antidiabetic targets. Individual knockdown of PTPN9 and DUSP9 in 3T3-L1 preadipocytes increased AMPK phosphorylation, respectively, and furthermore, concurrent knockdown of both PTPN9 and DUSP9 synergistically increased AMPK phosphorylation. Next, 658 natural products were screened to identify dual inhibitors of both PTPN9 and DUSP9. Based on the selectivity and inhibition potency of the compounds, ginkgolic acid (GA) was selected for further study as a potential antidiabetic drug candidate. GA inhibited the enzymatic activity of PTPN9 (K_i = 53 µM) and DUSP9 (K_i = 2.5 µM) in vitro and resulted in a significant increase of glucose-uptake in differentiated C2C12 muscle cells and 3T3-L1 adipocytes. In addition, GA increased phosphorylation of AMPK in 3T3L1 adipocytes. In this study, GA as a dual targeting inhibitor of PTPN9 and DUSP9 increased glucose uptake in 3T3L1 and C2C12 cells by activating the AMPK signaling pathway. These results strongly suggest GA could be used as a therapeutic candidate for type 2 diabetes.

siRNA研究了几种破坏胰岛素信号通路的蛋白酪氨酸磷酸酶（PTP），以鉴定潜在的抗糖尿病靶标。在3T3-L1前脂肪细胞中单独敲低PTPN9和DUSP9分别增加AMPK磷酸化，此外，同时敲低PTPN9和DUSP9协同增加AMPK磷酸化。接下来，筛选了658种天然产物以鉴定PTPN9和DUSP9的双重抑制剂。基于化合物的选择性和抑制能力，银杏酸（GA）被选作潜在的抗糖尿病药物进行进一步研究。GA在体外抑制PTPN9（K _i  = 53 µM）和DUSP9（K _i  = 2.5 µM）的酶活性并导致分化的C2C12肌肉细胞和3T3-L1脂肪细胞的葡萄糖摄取显着增加。此外，GA增强了3T3L1脂肪细胞中AMPK的磷酸化。在这项研究中，GA作为PTPN9和DUSP9的双重靶向抑制剂，可通过激活AMPK信号通路来增加3T3L1和C2C12细胞的葡萄糖摄取。这些结果强烈暗示GA可以用作2型糖尿病的治疗候选物。