Acute molecular mechanisms responsive to feeding and meal constitution in mesenteric adipose tissue.

To identify the acute effects of feeding on mesenteric fat, we have performed a transcriptomic study in the mesenteric adipose tissue after low-fat (LF) and high-fat (HF) meal ingestion. After fasting, one group of mice was killed and the others were fed ad libitum with HF or LF meal, and killed 3 h after the ingestion. Serial analysis of gene expression (SAGE) was performed, generating approximately 150,000 tags/sample. The results were confirmed using quantitative real-time PCR (qRT-PCR). Transcripts involved in lipid biosynthesis were upregulated only by LF meal, whereas intracellular lipid catabolism was repressed by feeding. Apoptotic genes were downregulated, whereas antiapoptosis and proteolysis were upregulated by feeding. The expression levels of genes coding for adiponectin and ribosomal proteins were decreased by HF meal, as well as transcripts involved in mRNA processing, cytoskeleton, and extracellular matrix. Several other fat-responsive genes were identified, including diverse uncharacterized transcripts. These results revealed that mesenteric adipose tissue transcriptome was responsive to food intake and was affected differently according to meal constitution. The identification of uncharacterized transcripts regulated by LF and HF meals is a first step toward further understanding the early mechanisms of diet-induced obesity as well as discovering new therapeutic targets for obesity-related diseases.