ChREBP expression in the liver, adipose tissue and differentiated preadipocytes in human obesity.

ChREBP is an essential transcription factor for lipogenesis. Its physiological role in adipose tissue has been studied only to a small extent and the control of its expression remains unknown in human adipocytes. We have studied ChREBP mRNA and protein expression levels in the liver and the omental (OM) and subcutaneous (SC) adipose tissues from obese and lean subjects, as well as in human differentiated preadipocytes. Liver and OM and SC adipose tissue biopsies were obtained from lean and obese patients. Human preadipocytes were isolated from the adipose tissues from obese patients and differentiated under adipogenic conditions. ChREBP expression levels were quantified by RT-PCR and Western blot analysis. We found opposing results in terms of ChREBP regulation in the liver and adipose samples. ChREBP increased in the liver from obese compared to lean subjects, whereas the expression decreased in both adipose tissues. The mRNAs of other adipogenic markers were checked in these tissues. The pattern of FASN was similar to the one for ChREBP, ADCY3 decreased in both adipose tissues from obese patients, AP2 decreased only in OM adipose tissue of obese patients and ATGL did not change. The levels of ChREBP mRNA and protein showed dramatic increases during the differentiation of human OM and SC preadipocytes. In conclusion, ChREBP expression has an opposite regulation in the liver and adipose tissue from obese subjects which is compatible with the increased hepatic lipogenesis and decreased adipocytic lipogenesis found in these patients. The dramatic increase of ChREBP mRNA and protein levels during preadipocyte differentiation suggests a role in adipogenesis.