Irisin rescues diabetic cardiac microvascular injury via ERK1/2/Nrf2/HO-1 mediated inhibition of oxidative stress

Aims: Cardiac microvascular dysfunction is a common feature across cardiovascular complications in diabetes, while effective therapy remains elusive. This study was designed to evaluate the effect of irisin on cardiac microvascular injury in type 2 diabetes mellitus (T2DM).

Methods: T2DM was induced in C57BL/6J mice. A cohort diabetic mice received a 12-week treatment of irisin. Cardiac function and microvessel density were evaluated. Whether irisin directly regulates cardiac microvascular endothelial cells (CMECs) function was determined in vitro. Discovery-drive approaches followed by cause-effect analysis were used to uncover the molecular mechanisms.

Results: Irisin improved cardiac function in diabetic mice, and increased microvessel density. In vitro study revealed that irisin promoted CMECs proliferation and reduced high glucose and high lipid (HGHL)-induced apoptosis. Mechanistically, irisin increased mRNA and protein levels of heme oxygenase 1 (HO-1), superoxide dismutase 1 and superoxide dismutase 2, among which HO-1 ranked top. Irisin stimulated the phosphorylation of extracellular regulated protein kinases (ERK) 1/2 and nuclear factor erythroid-derived 2-like 2 (Nrf2) nuclear translocation, while U0126 (the inhibitor of ERK1/2) inhibited irisin-induced Nrf2 nuclear translocation and HO-1 expression. Nrf2 siRNA inhibited irisin's antioxidative effects.

Conclusion: Irisin could rescue cardiac microvessels against oxidative stress and apoptosis in diabetes via ERK1/2/Nrf2/HO-1 pathway.