The suppressive effect of Gelidium amansi-EtOH extracts on the adipogenesis with MAPK signals in adipocytes with or without macrophages

Abstract

To elucidate the anti-inflammatory and anti-adipogenetic effects of Gelidium amansii (GA) ethanol extracts and their mechanisms, we performed two culture systems, adipocytes cultured with or without macrophages. Purified GA-3 fraction (GAE) contains high flavonoids and phenolics, reduced the mRNA levels of PPARγ and C/EBPα with GLUT4 expression in adipocyte with or without macrophages. GAE also increased the protein expression of HSL and ATGL enzymes, lipolysis biomarkers in fat cells. In co-culture system, GAE suppressed not only the transcription factors for adipogenesis, but also the production of pro-inflammatory cytokines, TNF-α. Compared to MAPK pathways such as JNK and p-38, the phosphorylation of both ERK1/2 (Thr202/Tyr204) was strongly suppressed by GAE with dose-dependent manner in both culture system. Otherwise, an increased JNK expression caused by GAE treatments blocked an insulin-induced GLUT4 translocation in adipocytes culture. In conclusion, GAE depressed the expression of adipogenetic genes, corresponding to a reduction in fat accumulation while preadipocytes developed into adipocytes with the modulation of MAPK pathways and inflammatory cytokines.