preadipocyte

Preadipocytes are adipocyte progenitor cells located in adipose tissue. They are derived from mesenchymal stem cells and reside within the stromal-vascular fraction of white and brown fat depots. Preadipocytes serve as a reservoir that can proliferate and, upon appropriate signals, differentiate into mature adipocytes.

During adipogenesis, preadipocytes undergo clonal expansion followed by activation of a transcriptional cascade. Early regulators such as C/EBPβ and C/EBPδ induce the expression of PPARγ and C/EBPα, which drive terminal differentiation. Hormonal signals (for example, insulin and glucocorticoids) cooperate with these transcription factors to promote lipid accumulation and the development of insulin-responsive, mature adipocytes.

Markers and identification: Pref-1 (Dlk1) is a common marker of immature preadipocytes, with its expression typically declining as differentiation proceeds. Mature adipocytes express markers such as FABP4, adiponectin, and perilipin. In mice, additional surface markers like PDGFRα and Sca-1 are used to characterize adipocyte progenitors within the stromal-vascular fraction.

Location, function, and relevance: Preadipocytes contribute to adipose tissue plasticity and mass expansion through hyperplasia. In obesity and metabolic disease, their differentiation dynamics influence tissue remodeling and inflammatory responses. Preadipocytes can generally differentiate within white adipose tissue, and under certain conditions have the potential to adopt alternate mesenchymal lineages, illustrating their role in tissue development and homeostasis.