The Wilms' Tumor (WT1) Gene

Louise Cleal, You-Ying Chau

Nicholas Hastie

The current global obesity epidemic has triggered increased interest in adipose tissue biology. A major area of attention for many is adipose tissue development. A greater understanding of adipocyte ontogeny could be highly beneficial in answering questions about obesity-associated disease. Recent work has shown that a proportion of mature adipocytes in visceral white adipose tissue are derived from Wt1-expressing adipocyte precursor cells. These adipocyte precursor cells reside within the adipose tissue itself, and are a constituent of the stromal vascular fraction (SVF), along with other, non-adipogenic, cell types. Crucially, heterogeneity exists within the adipocyte precursor population, with only a proportion of cells expressing Wt1. Moreover, it appears that this difference in the precursor cells may influence the mature adipocytes, with Wt1-lineage-positive adipocytes having fewer, larger lipid droplets than the Wt1-lineage negative. Using fluorescence-activated cell sorting, based on specific marker profiles, it is possible to isolate the adipocyte precursor cells from the SVF. Subsequently, this population can be divided into Wt1-expressing and non-expressing fractions, therefore permitting further analysis of the two cell populations, and the mature adipocytes derived from them. In this chapter we outline a method by which adipocyte precursor cells can be isolated, and how, using a specific mouse model, Wt1-expressing and non-expressing cells can be separated.