Molecular Genetics of Adipocytes

Description of projects available to graduate students:
Recently, long-held assumptions that fat cells (adipocytes) are stable and long-lived have been scientifically debunked. It is now appreciated that adipose tissue turns over at a pace of ~10%/year and its cellular homeostasis is subject to tight physiological regulation at least at the levels of death and regeneration. Our lab has been developing several molecular genetic projects that address mechanisms of these homeostatic processes. Among these, potential graduate projects include:
1. Novel death mechanisms of adipocytes following loss of PPARγ – we developed a twist of the standard loxP-Cre system, in which Cre-mediated deletion of PPARγ activates a latent nuclear isoform of YFP (yellow fluorescent protein). Using direct fluorescent and immunofluorescent detection of nYFP in vivo and in vitro, we can now follow the precise fate of adipocytes upon loss of PPARγ. Our initial observations suggest that these cells are subject to a rapid and efficient non-apoptotic cell death mechanism. Graduate projects include characterization of this non-canonical death pathway, identifying and characterizing the PPARγ target gene(s) that subvert it, and later on evaluating the role of this pathway in the physiology of feeding and obesity.
2. Adipose tissue regeneration – Several project in the lab address regenerative mechanisms of adipose tissue during early development, following genetically engineered death and in lipodystrophy (a degenerative disease stemming from reduced viability of adipocytes). Topics of interest include the definitive identification and characterization of adipocyte progenitors, molecular cues that induce progenitor deployment, homing and integration during adipose tissue regeneration, and in the long run therapeutic potentials of adipocyte progenitors in obesity-associated metabolic diseases.

Techniques graduate student will learn:
• Gene targeting: construct design, recombineering, ES cell targeting, embryo manipulation, complex genetic crosses.
• Gene expression analysis: qPCR, transfections, reporter analysis, Blotting (Northern, Western), in situ hybridization, immunodetection.
• Cell culture: ES cells, primary fibroblasts, primary adipocytes, adipogenic assays.
• Histology and Imaging: microdissection, sectioning, light and fluorescent microscopy.