| Abstract: | Thioredoxin‐interacting protein (Txnip), a negative regulator of thioredoxin, has become an attractive therapeutic target to alleviate metabolic diseases. Our previous data demonstrated that geniposide improved glucose‐stimulated insulin secretion by accelerating Txnip degradation and prevented the early‐stage apoptosis of pancreatic β cells induced by palmitate, but the underlying mechanisms are still unclear. The objective of this study is to identify the role of Txnip in geniposide preventing the apoptosis of pancreatic β cells induced by high glucose and palmitate (HG/PA). The results revealed that geniposide attenuated HG/PA‐induced cell apoptosis and the expression of Bax and caspase‐3, while increasing mitochondrial membrane potential and the anti‐apoptotic protein levels of heme‐oxygenase‐1 (HO‐1) and Bcl‐2 in INS‐1 rat pancreatic β cells. Knockdown of the Txnip gene raised the levels of anti‐apoptotic proteins HO‐1 and Bcl‐2 and geniposide potentiated the effect of Txnip when the INS‐1 cells were challenged by HG/PA. Furthermore, geniposide enhanced the adoptive unfolded protein response by increasing the phosphorylation of PERK/eIF2α and IRE1α in HG/PA‐treated INS‐1 cells. The results together suggest that geniposide might be useful to antagonize glucolipotoxicity and Txnip might be a pleiotropic cellular factor in pancreatic β cells. |
