Irisin attenuates angiotensin II-induced cardiac fibrosis via Nrf2 mediated inhibition of ROS/ TGFβ1/Smad2/3 signaling axis

Angiotensin II-related cardiac fibrosis is one of the key pathological changes of the hypertrophied left ventricle in various heart disease. Irisin was recently reported to confer cardio-protective and anti-oxidative effects, while whether it can reverse the renin-angiotensin-aldosterone system(RAAS) activation related(angiotensin II-induced) cardiac fibrosis is unknown. In this study, we found that angiotensin II-induced cardiac dysfunction and fibrotic responses were dampened by irisin treatment in mice. Mechanistically, angiotensin II induced robust ROS generation, which in turn triggered activation of pro-fibrotic TGF beta 1-Smad2/3 signaling and subsequent collagen synthesis and fibroblast-myofibroblast transformation in cardiac fibroblasts. In contrast, Irisin treatment suppressed angiotensin II-induced ROS generation, TGF beta 1 activation, collagen synthesis and fibroblast-myofibroblast transformation, the effects of which was accompanied by Nrf2 activation and also abolished by a Nrf2 targeted siRNA. Taken together, we here identified irisin as a promising anti-fibrotic therapeutic for angiotensin II-related cardiac fibrosis.