IL-11 promotes Ang II-induced autophagy inhibition and mitochondrial dysfunction in atrial fibroblasts

This study aimed to investigate potential targets for the pathogenesis of atrial fibrillation to facilitate the development of effective treatments. Atrial fibroblasts were isolated and stimulated with 1 mu M angiotensin-II (Ang-II) for 24 h. To increase interleukin 11 (IL-11) expression, overexpression plasmids were transfected into atrial fibroblasts. The role and the underlying mechanism of IL-11 in atrial fibrillation were examined by immunofluorescence, measurements of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP), and western blotting assays. Results demonstrated that IL-11 was upregulated in Ang-II-elicited atrial fibroblasts. Ang-II treatment increases alpha-smooth muscle actin (alpha-SMA), ROS and MMP levels, and p62 expression but decreases microtubule-associated protein light chain 3 II/I (LC3 II/I) and Beclin-1 expressions in atrial fibroblasts. These effects were further amplified by IL-11 overexpression. Mechanistically, the mammalian target of rapamycin (mTOR) pathway expression was enhanced in Ang-II-induced atrial fibroblasts, which was further elevated by IL-11 upregulation. IL-11 facilitates Ang II-induced differentiation of atrial fibroblasts into myofibroblasts by promoting oxidative stress, mitochondrial dysfunction, and autophagy inhibition through the mTOR pathway.