Academic Interests
Dr. Cohen's lab focuses on three areas: (1) the role of nuclear receptor corepressors in hormone action; (2) the role of the extracellular matrix in adipocyte biology; and (3) various topics in clinical thyroidology. In terms of the first area, we are currently focusing on the corepressor SMRT and its function in the adipocyte. Although the adipocyte was previously considered solely an energy storage depot, we now understand that it’s an active endocrine cell. Adipocyte differentiation is also uniquely dependent on the nuclear receptor PPARgamma. His initial studies showed that SMRT regulates PPARgamma transcriptional activity and, in fact, dictates the degree of activation induced by thiazolidinediones, which are exogenous PPARgamma ligands used in the treatment of Type 2 diabetes. More recently, he has designed mice with decreased SMRT levels. These mice exhibit normal weight on a chow diet, but develop increased adiposity when fed a high-fat diet. Interestingly, adipocytes derived from these mice exhibit enhanced insulin actions, even in the setting of increased adiposity. These findings lend support to the hypothesis that impairments in the ability to expand fat mass appropriately in the setting of positive energy balance may lead to metabolic derangements in obesity and Type 2 diabetes. Dr. Cohen also studies the role of the extracellular matrix in adipose tissue, and have recently shown that deletion of the laminin alpha-4 chain leads to resistance to obesity; his current work aims to define how the extracellular matrix directly dictates adipocyte function.
Clinical Interests
Hyperthyroidism and hypothyroidism, thyroid cancer, pituitary disorders, general endocrinology