Gene expression profiling related to androgen and insulin metabolism pathway in well-trained and competitive athletes

The human body has a wide range of possibilities to adapt itself to sport activity. Many of these exercise specific adjustement are mediated by changes in the gene expression profile. Most of the actual study to better understand the changes in the gene expression as a conseguence of sport activity, were made on the muscle biopsies to identified the muscle transcriptome adaptation to physical exercise. Only a few investigators have examined the effect of exercise on specific PBMC (peripheral blood mononuclear cells) and so whether exercise changes gene expression in peripheral circulating blood cells is not fully understood. The androgen have an anabolic effects on the skeletal muscle and mediates the testosterone action which regulates the body composition leaning the body mass and decreasing the fat mass in young men. This reciprocal change in lean and fat mass induced by androgens is best explained by the hypothesis that androgens promote the commitment of mesenchymal pluripotent cells into myogenic lineage and inhibit adipogenesis through an androgen receptor mediated pathway. The aim of our study is to investigate changes in gene expression profiles in PBMC according to a different degree of sporting activity (controls, well trained and competitive athletes). In particular we have recruited 200 samples (90 athlets who play agonistic sporting activity, 70 athlets who play weekly sport exercise and 40 controls, subjects who do not play any sporting activity). To identify genes of which expression pattern could be modulated under physical exercise, we developed a low-density home made oligoarray composed of 190 genes selected on the basis of their proved or potential role in androgen and insulin biosintesis and metabolism pathway (Andro-Chip 2). The genes were subdivided in different classes according to the following criteria: genes regulating the androgen metabolism, androgen receptor (AR) and genes that bind to the AR-complex and acts as AR co-regulators (such as ARA70), genes whose expression is androgen-regulated (ARGs) and genes involved in the insulin signalling pathway which play an important role during physical exercise. First of all we demonstrated that all genes fixed on the “Androchip 2” show a detectable expression levels in peripheral blood cells (PBMC). Therefore PBMC represents an attractive, clinically accessible tissue for the identification of novel biomarkers. In fact alterations in the expression profiles of blood cells are characteristic in a wide range of disease and under various enviromental pressures such as exercise. AndroChip 2 gene signature identified in the athletes a total of 77 genes differentially expressed (FC 1,5). In particular 9 of these genes were overexpressed and 68 are underexpressed. Overexpressed genes included genes involved in the anabolic process (in particular AKT2, CYCLIND1) and genes involved in the insulin metabolism pathway like IGF1 and IGFBP2; whereas the underexpressed genes were genes involved in the catabolism process (in particular UGT2B17, FOXO3). Microarray data were confirmed by quantitative real time PCR assay (QRT-PCR). Our results show how the espression profiles of androgen and insulin metabolism genes changes according the sports activity degree in a readly obtainable tissue like PBMC. In particular identifing genes which the changes in gene expression can be detected in circulating blood cells, could be very helpfull to discover novel molecular biomarkers that could be used to identify doping use by anabolic steroids in sport activity. Therefore, better understand the changes in the gene expression as a conseguence of sport activity, is extremly important to identify the changes in the gene expression as a conseguente of anabolic steroid assumption