The increased incidence of obesity and metabolic disease underscores the importance of elucidating the biology of adipose tissue development. The recent discovery of cell surface markers for prospective identification of adipose precursor cells (APCs) in vivo will greatly facilitate these studies, yet tools for specifically targeting these cells in vivo have not been identified. Here, we survey three transgenic mouse lines, Fabp4-Cre, PdgfRα-Cre, and Prx1-Cre, precisely assessing Cre-mediated recombination in adipose stromal populations and mature tissues. Our data provide key insights into the utility of these tools to modulate gene expression in adipose tissues. In particular, Fabp4-Cre is not effective to target APCs, nor is its activity restricted to these cells. PdgfRα-Cre directs recombination in the vast majority of APCs, but also targets other populations. In contrast, adipose expression of Prx1-Cre is chiefly limited to subcutaneous inguinal APCs, which will be valuable for dissection of APC functions among adipose depots.

Obesity is driven by excess caloric intake, which leads to the expansion of adipose tissue by hypertrophy and hyperplasia. Adipose tissue hyperplasia results from the differentiation of adipocyte precursor cells (APCs) that reside in adipose depots. Investigation into this process has elucidated a network of mostly transcription factors that drive APCs through the differentiation process. Using in vitro and in vivo approaches, our study revealed a signaling pathway that inhibited the initiation of the adipocyte differentiation program. Mouse adipocytes secreted the extracellular protease ADAMTS1, which triggered the production of the cytokine pleiotrophin (PTN) through the Wnt/β-catenin pathway, and promoted proliferation rather than differentiation of APCs. Glucocorticoid exposure in vitro or in vivo reduced ADAMTS1 abundance in adipocytes. In addition, mice fed a high-fat diet showed decreased Adamts1 expression in the visceral perigonadal adipose depot, which expanded by adipogenesis in response to the diet, and increased Adamts1 expression in the subcutaneous inguinal adipose depot, which did not induce adipogenesis. Similar to what occurred in mouse subcutaneous adipose tissue, diet-induced weight gain increased the expression of ADAMTS1, PTN, and certain Wnt target genes in the subcutaneous adipose depot of human volunteers, suggesting the relevance of this pathway to physiological adipose tissue homeostasis and the pathogenesis of obesity. Thus, this pathway functions as a toggle on APCs, regulating a decision between differentiation and proliferation and coordinating the response of adipose tissue to systemic cues.