Expression Profile in Omental and Subcutaneous Adipose Tissue from Lean and Obese Subjects. Repression of Lipolytic and Lipogenic Genes

The adipose tissue is a highly regulated endocrine and paracrine organ that secretes a wide variety of biologically active molecules involved in the control of energy balance and the regulation of body weight. Our work aimed to analyze the dysregulation of the adipocyte metabolism and compare the gene expression patterns between omental (OM) and subcutaneous (SC) adipose tissue from obese and lean subjects by using whole-genome DNA microarrays. OM and SC adipose tissues were obtained from 43 obese subjects undergoing bariatric surgery and from six lean individuals. Gene expression analysis was performed by whole-genome microarrays and Taqman RT-PCR. The analysis of microarrays showed upregulation of 545 genes in OM and 47 in SC adipose tissue, whereas 723 and 27 genes were downregulated in OM and SC tissue, respectively, in obese patients. Significantly altered genes showed at least a twofold change of p < 0.05. Validation of the arrays with 28 genes was carried out by using low density microfluidic cards which confirmed the changes found in most genes. We focused on the altered expression of gene coding for enzymes and transcription factors involved in lipid metabolism. Interestingly, some of these genes have not been previously described in obesity. Our results show that adipose tissue from obese subjects entails defense mechanisms against an excessive expansion and fat accumulation, repressing both lipogenesis and lipolysis.