Nicorandil regulates the macrophage skewing and ameliorates myofibroblasts by inhibition of RhoA/Rho‐kinase signalling in infarcted rats |
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| Authors: | Tsung‐Ming Lee Shinn‐Zong Lin Nen‐Chung Chang |
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| Affiliation: | 1. Cardiology Section, Department of Medicine, An‐Nan Hospital, China Medical University, Tainan, Taiwan;2. Department of Medicine, China Medical University, Taichung, Taiwan;3. Cardiovascular Research Laboratory, China Medical University Hospital, Taichung, Taiwan;4. Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan;5. Department of Neurosurgery, Tzu Chi University Hospital, Hualien, Taiwan;6. Bioinnovation Center, Tzu Chi foundation, Hualien, Taiwan;7. Division of Cardiology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan |
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| Abstract: | We have demonstrated that ATP‐sensitive potassium (KATP) channel agonists attenuated fibrosis; however, the mechanism remained unclear. Since RhoA has been identified as a mediator of cardiac fibrosis, we sought to determine whether the anti‐fibrotic effects of KATP channel agonists were mediated via regulating macrophage phenotype and fibroblast differentiation by a RhoA/RhoA‐kinase‐dependent pathway. Wistar male rats after induction of myocardial infarction were randomized to either vehicle, nicorandil, an antagonist of KATP channel glibenclamide, an antagonist of ROCK fasudil, or a combination of nicorandil and glibenclamide or fasudil and glibenclamide starting 24 hrs after infarction. There were similar infarct sizes among the infarcted groups. At day 3 after infarction, post‐infarction was associated with increased RhoA/ROCK activation, which can be inhibited by administering nicorandil. Nicorandil significantly increased myocardial IL‐10 levels and the percentage of regulatory M2 macrophages assessed by immunohistochemical staining, Western blot, and RT‐PCR compared with vehicle. An IL‐10 receptor antibody increased myofibroblast infiltration compared with nicorandil alone. At day 28 after infarction, nicorandil was associated with attenuated cardiac fibrosis. These effects of nicorandil were functionally translated in improved echocardiographically derived cardiac performance. Fasudil showed similarly increased expression of M2 macrophages as nicorandil. The beneficial effects of nicorandil on fibroblast differentiation were blocked by adding glibenclamide. However, glibenclamide cannot abolish the attenuated fibrosis of fasudil, implying that RhoA/RhoA‐kinase is a downstream effector of KATP channel activation. Nicorandil polarized macrophages into M2 phenotype by inhibiting RhoA/RhoA‐kinase pathway, which leads to attenuated myofibroblast‐induced cardiac fibrosis after myocardial infarction. |
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| Keywords: | ATP‐sensitive potassium channel interleukin‐10 M2 macrophage myocardial infarction myofibroblast |
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