Angiotensin-(1-7) induces beige fat thermogenesis through the Mas receptor

Angiotensin-(1-7) [Ang-(1-7)], a component of the renin angiotensin system, is a vasodilator that exerts its effects primarily through the Mas receptor. The discovery of the Mas receptor in white adipose tissue (WAT) suggests an additional role for this peptide. The aim of the present study was to assess whether Ang-(1-7) can induce the expression of thermogenic genes in white adipose tissue and increase mitochondrial respiration in adipocytes.

Stromal Vascular fraction (SVF)-derived from mice adipose tissue was stimulated for one week with Ang-(1-7), then expression of beige markers and mitochondrial respiration were assessed. Mas^+/+ and Mas^-/- mice fed a control diet or a high fat-sucrose diet (HFSD) were exposed to a short or long term infusion of Ang-(1-7) and body weight, body fat, energy expenditure, cold resistance and expression of beige markers were assessed. Also, transgenic rats overexpressing Ang-(1-7) were fed with a control diet or a high fat-sucrose diet and the same parameters were assessed. Ang-(1-7) circulating levels from human subjects with different body mass index (BMI) or age were measured.

Incubation of adipocytes derived from SVF with Ang-(1-7) increased the expression of beige markers. Infusion of Ang-(1-7) into lean and obese Mas^+/+mice also induced the expression of Ucp1 and some beige markers, an effect not observed in Mas^-/- mice. Mas^-/- mice had increased body weight gain and decreased cold resistance, whereas rats overexpressing Ang-(1-7) showed the opposite effects. Overexpressing rats exposed to cold developed new thermogenic WAT in the anterior interscapular area. Finally, in human subjects the higher the BMI, low circulating concentration of Ang-(1-7) levels were detected. Similarly, the circulating levels of Ang-(1-7) peptide were reduced with age.

These data indicate that Ang-(1-7) stimulates beige markers and thermogenesis via the Mas receptor, and this evidence suggests a potential therapeutic use to induce thermogenesis of WAT, particularly in obese subjects that have reduced circulating concentration of Ang-(1-7).