Fig. 7.

A model of SAT and VAT adipocyte lineage specification. In SAT, all progenitor cells (gray) are of the PDGFRα⁺ lineage and give rise to PDGFRβ⁻ and PDGFRβ⁺ preadipocytes (orange) that can differentiate into beige adipocytes rich in mitochondria (brown) or unilocular white adipocytes. SAT adipocytes can transiently acquire lipid-free ASC morphology and drift from mitochondria-rich beige to white as a function of PDGFRβ expression in de-differentiated preadipocytes. In VAT, some adipocytes are also derived from the PDGFRα⁺ progenitor lineage without PDGFRβ expression in preadipocytes, whereas other adipocytes are derived from a distinct PDGFRα-negative progenitor cells expressing only PDGFRβ.