On the role of liver X receptors in lipid accumulation in adipocytes.

The pivotal role of liver X receptors (LXRs) in the metabolic conversion of cholesterol to bile acids in mice is well established. More recently, the LXRalpha promoter has been shown to be under tight regulation by peroxisome proliferator-activated receptors (PPARs), implying a role for LXRalpha in mediating the interplay between cholesterol and fatty acid metabolism. We have studied the role of LXR in fat cells and demonstrate that LXR is regulated during adipogenesis and augments fat accumulation in mature adipocytes.

Microarray analyses during adipogenesis: understanding the effects of Wnt signaling on adipogenesis and the roles of liver X receptor alpha in adipocyte metabolism.

Wnt signaling maintains preadipocytes in an undifferentiated state. When Wnt signaling is enforced, 3T3-L1 preadipocytes no longer undergo adipocyte conversion in response to adipogenic medium. Here we used microarray analyses to identify subsets of genes whose expression is aberrant when differentiation is blocked through enforced Wnt signaling.

Liver X receptors as insulin-mediating factors in fatty acid and cholesterol biosynthesis.

The nuclear receptor liver X receptor (LXR) alpha, an important regulator of cholesterol and bile acid metabolism, was analyzed after insulin stimulation in liver in vitro and in vivo. A time- and dose-dependent increase in LXRalpha steady-state mRNA level was seen after insulin stimulation of primary rat hepatocytes in culture. A maximal induction of 10-fold was obtained when hepatocytes were exposed to 400 nm insulin for 24 h.