ABSTRACT
OBJECTIVE: Adipogenesis can be spatially and temporally regulated by extracellular matrix (ECM). We hypothesized that the regulation of hyaluronic acid (HA), a component of the ECM, can affect adipogenesis in fat cells. The effects of HA on adipogenesis were investigated in vitro in 3T3-L1 cells and in vivo in high-fat diet-feeding C57BL/6J mice. METHODS: We investigated the effects of HA by degradation of pre-existing or synthesized HA and artificial inhibition of HA synthesis in adipogenesis. RESULTS: In vitro adipogenesis in 3T3-L1 cells was inhibited by treating them with exogenous hyaluronidase (HYAL) and with 4-methylumbelliferone, which inhibited the synthesis of HA in a concentration-dependent manner. In vivo, abdominal fat accumulation in high-fat diet-feeding C57BL/6J mice was suppressed by exogenous HYAL 10(4) IU injections, which was associated with reduction of lipid accumulation in liver and increase of insulin sensitivity. CONCLUSION: Changes in the ECM such as accumulation of high molecular weight of HA by HAS and degradation of HA by endogenous HYAL were essential for adipogenesis both in vitro and in vivo.
Subject(s)
3T3-L1 Cells/metabolism , Abdominal Fat/metabolism , Adipogenesis , Diet, High-Fat , Extracellular Matrix/metabolism , Hyaluronic Acid/metabolism , Animals , Cell Differentiation , Down-Regulation , Gene Expression Regulation , Insulin Resistance , Male , Mice , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/physiopathology , Non-alcoholic Fatty Liver Disease/prevention & control , Obesity/physiopathology , Obesity/prevention & controlABSTRACT
Cowden's disease, or multiple hamartoma syndrome, is an uncommon condition with characteristic mucocutaneous lesions associated with abnormalities of the breast, thyroid, and gastrointestinal tract. We describe a 32-year-old man with oral mucosal papillomatosis and plantar hyperkeratosis as a definite case of Cowden's disease according to the criteria proposed by Salem and Steck. The patient also had a thyroid mass and numerous gastrointestinal polyps endoscopically. Histologically the polyps were hamartomatous or hyperplastic polyps. The oral papillary lesions were fibroepithelial polyps and the thyroid mass was a follicular adenoma. We review the literature on this entity and summarize the pertinent findings. To the best of our knowledge, this is the first documented case of Cowden's disease in a Korean.