Adipocyte Precursors: Developmental Origins, Self-Renewal, and Plasticity

M.E. Symonds (ed.), Adipose Tissue Biology, DOI 10.1007/978-1-4614-0965-6_1, © Springer Science+Business Media, LLC 2012 Abstract 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 defi ning the transcriptional networks controlling the terminal differentiation of preadipocytes into mature adipocytes. However, the early steps that direct mesenchymal stem cells down the adipocyte lineage remain largely unknown. Similarly, the study of the developmental origin of adipocytes during embryogenesis has been largely disregarded until now. This review summarizes the surprising fi ndings that have recently emerged from in vivo lineage tracing studies, unraveling unsuspected developmental origins for white adipocytes. We will propose that the differential origin of adipocytes could also refl ect functional differences and site-specifi c regulations of adipose tissue. This chapter also reports recent work that has led to the identifi cation of discrete immature cell populations from which white adipocytes are derived in mice. A pool of adipocyte progenitors remains present in adipose tissue during adult life. This pool is responsible for the renewal of adipocytes and the potential of this tissue to expand in response to chronic energy overload. However, factors controlling proliferation and differentiation of human adipocyte progenitors are largely unknown. We will present stem cells derived from human adipose tissue (human Multipotent Adipose tissue Derived Stem (hMADS) cells) for studying proliferation and differentiation of adipocyte progenitors and will show that fi broblast growth factor 2 and activin A are key regulators of human adipocyte precursor self-renewal. Finally, we will discuss about the plasticity of hMADS cells.