Adiponectin exerts antiproliferative effect on human placenta via modulation of the JNK/c-Jun pathway

To determine the effects of adiponectin on human placenta during gestational diabetes mellitus (GDM) and on high glucose (HG)-induced BeWo cell proliferation. We examined the expression levels of adiponectin in control and GDM placenta using quantitative real-time PCR, Western blot, and immunohistochemistry (IHC). Cell proliferation and viability were assessed using a colorimetric assay (cell counting kit-8), PCNA immunocytochemical staining, and Western blot analysis of cyclin D1. Transfection of siRNA against c-jun was performed using Lipofectamine 2000. Cell cycle analysis was performed using propidium iodide staining and flow cytometry. Results show a decreased expression of adiponectin and an increased degree of trophoblast cell proliferation in GDM placenta compared to the normal placenta. Similarly, HG can promote BeWo cell proliferation that is associated with adiponectin down-regulation. This proliferation could be depressed by addition of exogenous adiponectin, i.e. adiponectin exerts antiproliferative effects on HG-induced trophoblast cells. Adiponectin suppresses the HG-induced BeWo cell proliferation by inhibiting the activation of JNK/c-jun. In conclusion, adiponectin inhibits HG-induced proliferation of BeWo cells through down-regulation of JNK/c-jun phosphorylation.