Factor for Adipocyte Differentiation 158 Gene Disruption Prevents the Body Weight Gain and Insulin Resistance Induced by a High-Fat Diet

摘要

To clarify the molecular mechanism of adipocyte differentiation, we previously isolated a novel gene, factor for adipocyte differentiation (fad) 158, whose expression was induced during the earliest stages of adipogenesis, and its product was localized to the endoplasmic reticulum. We found that the knockdown of fad 158 expression prevented the differentiation of 3T3-L1 cells into adipocytes. In addition, over-expression of fad 158 promoted the differentiation of NIH-3T3 cells, which do not usually differentiate into adipocytes. Although these findings strongly suggest that fad 158 has a crucial role in regulating adipocyte differentiation, the physiological role of the gene is still unclear. In this study, we generated mice in which fad 158 expression was deleted. The fad 158-deficient mice did not show remarkable changes in body weight or the weight of white adipose tissue on a chow diet, but had significantly lower body weights and fat mass than wild-type mice when fed a high-fat diet. Furthermore, although the disruption of fad 158 did not influence insulin sensitivity on the chow diet, it improved insulin resistance induced by the high-fat diet. These results indicate that fad 158 is a key factor in the development of obesity and insulin resistance caused by a high-fat diet.