title: Fatty acid binding protein 4 expression marks a population of adipocyte progenitors in white and brown adipose tissues.
abstract: Adipose tissues regulate metabolism, reproduction, and life span. The development and growth of adipose tissue are due to increases of both adipocyte cell size and cell number; the latter is mediated by adipocyte progenitors. Various markers have been used to identify either adipocyte progenitors or mature adipocytes. The fatty acid binding protein 4 (FABP4), commonly known as adipocyte protein 2 (aP2), has been extensively used as a marker for differentiated adipocytes. However, whether aP2 is expressed in adipogenic progenitors is controversial. Using Cre/LoxP-based cell lineage tracing in mice, we have identified a population of aP2-expressing progenitors in the stromal vascular fraction (SVF) of both white and brown adipose tissues. The aP2-lineage progenitors reside in the adipose stem cell niche and express adipocyte progenitor markers, including CD34, Sca1, Dlk1, and PDGFRα. When isolated and grown in culture, the aP2-expressing SVF cells proliferate and differentiate into adipocytes upon induction. Conversely, ablation of the aP2 lineage greatly reduces the adipogenic potential of SVF cells. When grafted into wild-type mice, the aP2-lineage progenitors give rise to adipose depots in recipient mice. Therefore, the expression of aP2 is not limited to mature adipocytes, but also marks a pool of undifferentiated progenitors associated with the vasculature of adipose tissues. Our finding adds to the repertoire of adipose progenitor markers and points to a new regulator of adipose plasticity.
authors.affiliation: Department of Animal Science, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Tizhong
authors.initials: T
authors.lastname: Shan
authors.forename: Weiyi
authors.initials: W
authors.lastname: Liu
authors.forename: Shihuan
authors.initials: S
authors.lastname: Kuang
mesh_terms: D017667:Adipocytes / Q000378:metabolism*; D000273:Adipose Tissue / Q000166:cytology / Q000378:metabolism*; D002001:Adipose Tissue, Brown / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D049109:Cell Proliferation; D002469:Cell Separation; D002478:Cells, Cultured; D050556:Fatty Acid-Binding Proteins; D005434:Flow Cytometry; D051379:Mice; D060888:Real-Time Polymerase Chain Reaction; D013234:Stem Cells / Q000378:metabolism
chemical_list: C493410:FABP4 protein, human; D050556:Fatty Acid-Binding Proteins