Activation of AMPK prevents monocrotaline-induced pulmonary arterial hypertension by suppression of NF-κB-mediated autophagy activation

It has been shown that activation of autophagy is involved in the development of pulmonary arterial hypertension (PAH). Meanwhile, activation of nuclear factor-kappaB (NF-κB) has been found to induce autophagy in several types of human diseases including cancer and cardiac diseases. However, it is still unknown whether NF-κB mediates autophagy activation in PAH, and whether activation of adenosine monophosphate-activated protein kinase (AMPK) benefits PAH by modulation of NF-κB and autophagy. Rat models of PAH were established by intraperitoneally injection of monocrotaline (MCT). The right ventricle systolic pressure (RVSP), right ventricular hypertrophy index (RVHI), and percentage of medial wall thickness (%MT) were performed to evaluate the development of PAH. The translocation of NF-κB p65 from cytosol to nucleus, the protein levels of LC3A, LC3B, and RND3 were determined by immunoblotting. Metformin was used to activate AMPK. NF-κB and autophagy were significantly activated in MCT-induced PAH rats, this was accompanied with the reduction of RND3. Pharmacological inhibition of NF-κB suppressed MCT-induced activation of autophagy and down-regulation of RND3 expression and reduced RVSP, RVHI, and %MT in MCT-induced PAH rats. In addition, activation of AMPK by metformin suppressed NF-κB-mediated autophagy activation and down-regulation of RND3 and therefore reduced RVSP, RVHI, and %MT in MCT-induced PAH. NF-κB-induced autophagy activation and consequent down-regulation of RND3 contributes to the development of PAH in MCT-treated rats. Activation of AMPK prevents the development of PAH by targeting on NF-κB to suppress autophagy and vascular remodeling.