The present study was performed to examine a role of adipose differentiation-related protein (ADRP) in the process of liver steatosis. Immunohistochemical findings indicated that ADRP protein expression is increased in the hepatocytes in patients with fatty liver when compared with normal liver. ADRP protein expression is localized in the surface of lipid droplets in the hepatocytes. Increased expression of ADRP mRNA and protein was similarly observed in fatty liver in ob/ob mice and the liver steatosis induced by high fat diet in mice. The up-regulation of ADRP mRNA and protein in the liver by high fat diet was identified in the surface of lipid droplets in a time dependent manner. Recent studies demonstrated that up-regulation of PPARg in the hepatocytes is deeply involved in liver steatosis. To clarify whether ADRP expression is increased by PPARg activation in hepatocytes, we examined the effect of a PPARg ligand, troglitazone, on ADRP mRNA expression in HepG2 cells. ADRP mRNA expression was increased by troglitazone in dose and time dependent manners. All these results suggest that ADRP is up-regulated in liver steatosis in human and mice and that high fat diet increases expression of ADRP through PPARg activation, followed by induction of liver steatosis.
注記
Elsevier Inc., Wataru Motomura, Mitsutaka Inoue, Takaaki Ohtake, Nubuhiko Takahashi, Miho Nagamine, Satoshi Tanno, Yutaka Kohgo and Toshikatsu Okumura, Biochemical and Biophysical Research Communications , 340(4), 2006, 1111-1118.
