摘要：

The current epidemic of obesity and overweight has caused a surge of interest in the study of adipose tissue formation. Much progress has been made in defining the transcriptional networks controlling the terminal differentiation of preadipocytes into mature adipocytes. However, the earliest steps that direct mesenchymal stem cells located in adipose tissue (adipose-derived stem cells (ASCs)) down the adipocyte lineage remain largely unknown. In this chapter, we first focus on the identification of intrinsic and extrinsic factors regulating thebalance between human ASC proliferation and differentiation. We point out the role of factors secreted by undifferentiated ASCs, such a FGF2, activin A, Hedgehog molecules, or secreted by adipose tissue macrophages. We also outline the role of miRNAs in these processes. In a second part, the developmental origin of adipocytes during embryogenesis is discussed. We summarize the surprising findings that have recently emerged from in vivo lineage tracing studies, unravelling unsuspected developmental origins for white adipocytes. We examine the possibility that the differential developmental origin of adipocytes could also reflect functional site-specific regulations of adipose tissue. Finally, we present human-induced pluripotent stem cells as a novel model for investigating the earliest steps of human adipocyte development.

展开