Gene expression profiling of gluteal adipose tissue after prolonged bedrest

Adipose tissue is a complex and highly active metabolic and endocrine organ, with an important role in immune and inflammatory processes. Its dysfunction has been linked to development of insulin resistance, type 2 diabetes and cardiovascular disease. A sedentary lifestyle is associated to a quantitative and qualitative alteration of adipose tissue mass and function. Bed rest has been utilized as an experimental model to simulate physical inactivity. The aim of this study was to investigate the impact of physical inactivity on adipose tissue gene expression in healthy subjects. A total of 7 healthy subjects underwent gluteal adipose tissue biopsies before and after 14 days of bed rest; RNA was isolated and hybridized on RNA microarray chips in order to detect gene expression differences. A total of 308 genes were differently expressed after bed rest intervention; these genes were analyzed with bioinformatics database support (DAVID gene functional classification tool), to find potential functional-related gene groups and gene-disease associations. In silico analysis showed that 14 genes in our list have been previously involved in cardiovascular diseases, 8 genes in metabolic disorders and 12 genes in both. Among these, UCP3 (Uncoupling Protein 3) and BMP7 (bone morphogenetic protein 7) have been shown to be involved in energy expenditure and adipose tissue “browning”; TTR (transthyretin) is a known transport protein that carries the thyroid hormones (T4) and retinol-binding protein bound to retinol. Moreover several genes involved in inflammatory response such as CRP (CReactive Protein), IL1-beta and IL18 are differentially expressed after bedrest