Wang Sheng, Ge Liang, Zhang Dengwen, Wang Lin, Liu Hao, Ye Xiaodong, Liang Wanling, Li Jun, Ma Haichun, Cai Yin, Xia Zhengyuan
Department of Anesthesiology, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangdong, China.
Department of Anesthesiology, The University of Hong Kong, Hong Kong SAR, China.
Oxid Med Cell Longev. 2020 Jul 25;2020:7913418. doi: 10.1155/2020/7913418. eCollection 2020.
Constitutive nuclear factor kappa B (NFB) activation has been shown to exacerbate during myocardial ischemia/reperfusion (I/R) injury. We recently showed that miR-181c-5p exacerbated cardiomyocytes injury and apoptosis by directly targeting the 3'-untranslated region of protein tyrosine phosphatase nonreceptor type 4 (PTPN4). However, whether miR-181c-5p mediates cardiac I/R injury through NFB-mediated inflammation is unknown. Thus, the present study aimed to investigate the role of miR-181c-5p during myocardial I/R injury and explore its mechanism in relation to inflammation in H9C2 cardiomyocytes.
In hypoxia/reoxygenation (H/R, 6 h hypoxia followed by 6 h reoxygenation)-stimulated H9C2 cardiomyocytes or postischemic myocardium of rat, the expression of miR-181c-5p was significantly upregulated, which was concomitant increased NFB activity when compared to the nonhypoxic or nonischemic control groups. This is indicative that miR-181c-5p may be involved in NFB-mediated inflammation during myocardial I/R injury. To investigate the potential role of miR-181c-5p in H/R-induced cell inflammation and injury, H9C2 cardiomyocytes were transfected with the miR-181c-5p agomir. Overexpression of miR-181c-5p significantly aggravated H/R-induced cell injury (increased lactate dehydrogenase (LDH) level) and exacerbated NFB-mediated inflammation (greater phosphorylation and degradation of IB, phosphorylation of p65, and increased levels of proinflammatory cytokines tumor necrosis factor (TNF), interleukin (IL)-6, and IL-1). In contrast, inhibition of miR-181c-5p by its antagomir transfection had the opposite effect. Furthermore, overexpression of miR-181c-5p significantly enhanced lipopolysaccharide-induced NFB signalling. Additionally, knockdown of PTPN4, the direct target of miR-181c-5p, significantly aggravated H/R-induced phosphorylation and degradation of IB, phosphorylation of p65, and the levels of proinflammatory cytokines. PTPN4 knockdown also cancelled miR-181c-5p antagomir mediated anti-inflammatory effects in H9C2 cardiomyocytes during H/R injury.
It is concluded that miR-181c-5p may exacerbate myocardial I/R injury and NFB-mediated inflammation PTPN4, and that targeting miR-181c-5p/PTPN4/NFB signalling may represent a novel strategy to combat myocardial I/R injury.
已有研究表明，组成型核因子κB（NFκB）激活在心肌缺血/再灌注（I/R）损伤过程中会加剧。我们最近发现，miR-181c-5p通过直接靶向蛋白酪氨酸磷酸酶非受体4型（PTPN4）的3'-非翻译区，加剧了心肌细胞损伤和凋亡。然而，miR-181c-5p是否通过NFκB介导的炎症反应介导心脏I/R损伤尚不清楚。因此，本研究旨在探讨miR-181c-5p在心肌I/R损伤中的作用，并探讨其与H9C2心肌细胞炎症反应相关的机制。
在缺氧/复氧（H/R，6小时缺氧后6小时复氧）刺激的H9C2心肌细胞或大鼠缺血后心肌中，miR-181c-5p的表达显著上调，与非缺氧或非缺血对照组相比，同时NFκB活性也增加。这表明miR-181c-5p可能参与了心肌I/R损伤期间NFκB介导的炎症反应。为了研究miR-181c-5p在H/R诱导的细胞炎症和损伤中的潜在作用，用miR-181c-5p激动剂转染H9C2心肌细胞。miR-181c-5p的过表达显著加重了H/R诱导的细胞损伤（乳酸脱氢酶（LDH）水平升高），并加剧了NFκB介导的炎症反应（IκB的磷酸化和降解增加、p65磷酸化以及促炎细胞因子肿瘤坏死因子（TNF）、白细胞介素（IL）-6和IL-1水平升高）。相反，用其拮抗剂转染抑制miR-181c-5p则产生相反的效果。此外，miR-181c-5p的过表达显著增强了脂多糖诱导的NFκB信号传导。此外，miR-181c-5p的直接靶点PTPN4的敲低显著加重了H/R诱导的IκB磷酸化和降解、p65磷酸化以及促炎细胞因子水平。PTPN4敲低也消除了miR-181c-5p拮抗剂在H/R损伤期间对H9C2心肌细胞的抗炎作用。
得出结论，miR-181c-5p可能通过PTPN4加剧心肌I/R损伤和NFκB介导的炎症反应，并且靶向miR-181c-5p/PTPN4/NFκB信号通路可能代表一种对抗心肌I/R损伤的新策略。
