OBJECTIVEWe investigated the regulation of adipose tissue gene expression during different phases of a dietary weight loss program and its relation with insulin sensitivity.RESEARCH DESIGN AND METHODSTwenty-two obese women followed a dietary intervention program composed of an energy restriction phase with a 4-week very-low-calorie diet and a weight stabilization period composed of a 2-month low-calorie diet followed by 3–4 months of a weight maintenance diet. At each time point, a euglycemic-hyperinsulinemic clamp and subcutaneous adipose tissue biopsies were performed. Adipose tissue gene expression profiling was performed using a DNA microarray in a subgroup of eight women. RT–quantitative PCR was used for determination of mRNA levels of 31 adipose tissue macrophage markers (n = 22).RESULTSBody weight, fat mass, and C-reactive protein level decreased and glucose disposal rate increased during the dietary intervention program. Transcriptome profiling revealed two main patterns of variations. The first involved 464 mostly adipocyte genes involved in metabolism that were downregulated during energy restriction, upregulated during weight stabilization, and unchanged during the dietary intervention. The second comprised 511 mainly macrophage genes involved in inflammatory pathways that were not changed or upregulated during energy restriction and downregulated during weight stabilization and dietary intervention. Accordingly, macrophage markers were upregulated during energy restriction and downregulated during weight stabilization and dietary intervention. The increase in glucose disposal rates in each dietary phase was associated with variation in expression of sets of 80–110 genes that differed among energy restriction, weight stabilization, and dietary intervention.CONCLUSIONSAdipose tissue macrophages and adipocytes show distinct patterns of gene regulation and association with insulin sensitivity during the various phases of a dietary weight loss program.

Coronary artery disease (CAD) is the most prevalent cause of mortality and morbidity worldwide and the number of individuals at risk is increasing. To better manage cardiovascular diseases, improved tools for risk prediction including the identification of novel accurate biomarkers are needed. MicroRNA (miRNA) are essential post-transcriptional modulators of gene expression leading to mRNA suppression or translational repression. Specific expression profiles of circulating miRNA have emerged as potential noninvasive diagnostic biomarkers of diseases. The aim of this study was to identify the potential diagnostic value of circulating miRNA with CAD. Circulating miR-145, miR-155, miR-92a and let-7c were selected and validated by quantitative PCR in 69 patients with CAD and 30 control subjects from the cross-sectional study GENES. The expression of miR-145, miR-155 and let-7c showed significantly reduced expression in patients with CAD compared to controls. Multivariate logistic regression analysis revealed that low levels of circulating let-7c, miR-145 and miR-155 were associated with CAD. Receiver operating curves analysis showed that let-7c, miR-145 or miR-155 were powerful markers for detecting CAD. Furthermore, we demonstrated that the combination of the three circulating miRNA managed to deliver a specific signature for diagnosing CAD.

Vasoactive intestinal peptide (VIP)1 receptors in rats and humans recognize peptide histidine isoleucineamide (PHI) with high and low affinity, respectively. We took advantage of this phenotypic difference to identify the domain responsible for the selective recognition of PHI by rat and human receptors which display >80% sequence identity. After transfection of human and rat receptors in COS cells, the ratio of IC50 for PHI/IC50 for VIP (referred to as P/V) in inhibiting 125I-VIP binding was shown to be >1,000 and <40, respectively. Construction of eight rat/human receptor chimerae by overlap polymerase chain reaction and determination of their P/V ratios demonstrated that the critical domain for PHI recognition is present within a sequence comprising part of the first extracellular loop and third transmembrane domain. This domain contains three different amino acids numbered according to human and rat sequences, respectively, e.g. Gln207 (human) versus His208 (rat), Gly211 versus Ala212 and Met219 versus Val220. Site-directed mutagenesis introducing individual, double, or triple mutations in a chimeric construct revealed that all three amino acids were involved in the recognition of PHI. Triple mutations were then introduced in the wild-type receptors i.e. Q207H, G211A, M219V human VIP1 receptor and H208Q, A212G, V220M rat VIP1 receptor, resulting in a complete change in their phenotype from human to rat and from rat to human, respectively. The results demonstrate that three nonadjacent amino acids are responsible for the selective recognition of PHI by human and rat VIP1 receptors.