Oxidative Stress Activates Endothelial Innate Immunity via Sterol Regulatory Element Binding Protein 2 (SREBP2) Transactivation of MiRNA-92a
Background—Oxidative stress activates endothelial innate immunity and disrupts endothelial functions, including eNOS-derived NO bioavailability. Here, we postulated that oxidative stress induces sterol regulatory element binding protein 2 (SREBP2) and microRNA-92a (miR-92a), which in turn activate endothelial innate immune response, leading to dysfunctional endothelium.
Methods and Results—Using cultured endothelial cells (ECs) challenged by diverse oxidative stresses, hypercholesterolemic zebrafish, and Ang II-infused or aged mice, we demonstrated that SREBP2 transactivation of microRNA-92a (miR-92a) is oxidative stress-inducible. The SREBP2-induced miR-92a targets key molecules in endothelial homeostasis, including Sirtuin 1, Krüppel-like factor 2 (KLF2), and KLF4, leading to NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome activation and eNOS inhibition. In EC-specific SREBP2 transgenic mice, locked nucleic acid (LNA)-modified antisense miR-92a (LNA-92a) attenuates inflammasome, improves vasodilation, and ameliorates Ang II-induced and aging-related atherogenesis. In patients with coronary artery disease, the level of circulating miR-92a is inversely correlated with EC-dependent, flow-mediated vasodilation and is positively correlated with serum level of IL-1β.
Conclusions—Our findings suggest that SREBP2-miR-92a-inflammasome exacerbates endothelial dysfunction during oxidative stress. Identification of this mechanism may help in diagnosis and/or treatment of disorders associated with oxidative stress, innate immune activation, and endothelial dysfunction.
- endothelial dysfunction
- endothelial cell
- sterol regulatory element binding proteins
- oxidative stress
- Received October 14, 2014.
- Revision received December 16, 2014.
- Accepted December 19, 2014.