"MicroRNA Expression Profiling in human Subcutaneous Adipose Tissue"

MicroRNA are believed to be generally involved in more quantitative regulation of mammalian trait: therefore, mammalian conditions that have a strong genetic component and involve quantitative differences between the physiological and pathological conditions are strong candidates to be influenced by miRNA disregulations. The pool of this study is thus to investigate the possible role for miRNA imbalance in adipose tissue in the development of obesity. To date, microRNAs have been identified and evaluated in human preadipocytes (miR- 143) and mouse hepatocytes (miR-122). There is no study dealing with microRNA in subcutaneous adipose tissue (SAT) of obese patients. For this reason, we have performed an high-throughput screening by microarray analysis on 1,458 microRNAs in SAT from 20 morbidly obese patients (10 men and 10 female) versus pools of RNA from non obese subjects (3 men and 5 female). We were able to identify miRNAs differentially expressed comparing SAT from obese patients with respect to SAT from non-obese patients. The miR-519d was significantly higher in obese subjects than in the non obese pools. Using bioinformatic and functional analyses, we have demonstrated that the peroxisome proliferator activated receptor A (PPARA) gene resulted be a target of miR-519d. PPARA regulates the genes involved in fatty acid, glucose metabolism and inflammation (Cho et al., 2008). Therefore, it is conceivable that loss of PPARA could cause metabolic imbalance, thereby resulting in adipocyte hypertrophy in SAT from morbidly obese subjects. This project set the goal to be a part of the effort in understanding the biology and the role of this miR-519d during biogenesis of obesity.