Developmental and Functional Heterogeneity of White Adipocytes within a Single Fat Depot

We and others have previously observed that adipocytes and preadipocytes taken from different adipose tissue depots are characterized by differential expression of developmental and patterning genes (Dankel et al., 2010; Ferrer-Lorente et al., 2014; Gesta et al., 2006; Lee et al., 2017a; Lee et al., 2013; Macotela et al., 2012; Tchkonia et al., 2007; Yamamoto et al., 2010). To investigate how adipocyte heterogeneity and differences in the expression of developmental genes might impact the biology of adipocytes and preadipocytes, we created preadipocyte cell lines from the stromovascular fraction (SVF) isolated from the scapular white, inguinal, perigonadal, perirenal, and mesenteric fat pads of 6-week old male Immortomouse™ (Jat et al., 1991).During routine culture of the subcutaneous and visceral/perigonadal clonal cell lines, we observed extreme variation in media acidification rates that was unrelated to the fat pad of origin, the differentiation capacity of the cells, or the rate of their proliferation, suggesting metabolic heterogeneity. To further investigate this possibility, 24 clonal cell lines (12 each from subcutaneous and perigonadal fat) were selected based on variable media acidification rates, and their mRNA expression pattern determined by microarray analysis. The expression data was clustered using three different algorythms, and the consensus was used to categorize each type of adipose tissue. Immortomouse™ clonal preadipocyte cell lines were created from the stromovascular fraction (SVF) of the subcutaneous and perigonadal fat of a single 8 week-old male mouse. RNA was extracted, and used to run a microarray. Expression data was then used to cluster the cell lines into groups.