COLEC12 expression participates in trophoblast insulin resistance, and reverses celecoxib-mediated inhibition of COX2-PGE2 axis in gestational diabetes

Abstract

Purpose: To evaluate the contribution of collectin subfamily member 12 (COLEC12) in insulin resistance associated with gestational diabetes mellitus (GDM). Methods: Insulin resistance was induced in human placental trophoblast (HTR-8/SVneo) cells in vitro by incubating them with 1 μM insulin for 48 h.  Expression of COLEC12 was assessed using western blot and quantitative real time-polymerase chain reaction (qRT-PCR). Distribution of glucose transporters GLUT1 and GLUT4 was visualized using immunofluorescent staining. Furthermore, the level of reactive oxygen species (ROS) was evaluated by flow cytometry. Results: Insulin-resistant HTR-8/SVneo (IR-HTR-8/SVneo) cells showed significantly elevated COLEC12 expression (p < 0.001). Knocking down of COLEC12  in these cells led to a significant reduction in GLUT1 expression, and increase in both glucose consumption and GLUT4 expression (p < 0.001).  Furthermore, COLEC12 knockdown levels of ROS increased SOD expression in IR-HTR8/SVneo, while knockdown of COLEC12 reduced p-insulin receptor  substrate (IRS) (Ser307) protein expression, but increased p-IRS-1 (Tyr896), p-insulin receptor β (IRβ) (Tyr1361), and p-AKT levels. COLEC12 knockdown also  decreased cyclooxygenase-2 (COX-2) expression, resulting in lower prostaglandin E2 (PGE2) levels in IR-HTR-8/SVneo. COLEC12 over-expression  attenuated celecoxibinduced increase in glucose consumption, resulting in decreased COX2 and PGE2 levels. Conclusion: COLEC12 in IR-HTR-8/SVneo  cells has antioxidant effects that protect against insulin resistance. This protective effect is achieved through the down-regulation of COX-2/PGE2. These findings provide a potential strategy for the treatment of GDM.