Department of Pharmacology, Kyoto Prefectural University of Medicine, 465 Kajii-cho Kawaramachi-Hirokoji Kamigyo-ku, Kyoto 602-8566, Japan.
Department of Pharmacology, Kyoto Prefectural University of Medicine, 465 Kajii-cho Kawaramachi-Hirokoji Kamigyo-ku, Kyoto 602-8566, Japan; Department of Nephrology, Renmin Hospital of Wuhan University, 238 Jiefang Rd., Wuchang District, Wuhan 430060, China.
Free Radic Biol Med. 2018 May 20;120:277-288. doi: 10.1016/j.freeradbiomed.2018.03.053. Epub 2018 Mar 31.
Cardiac fibrosis is a common feature in failing heart and therapeutic strategy to halt the progression of fibrosis is highly needed. We here report on NOX1, a non-phagocytic isoform of superoxide-producing NADPH oxidase, which promotes cardiac fibrosis in a drug-induced myocardial injury model. A single-dose administration of doxorubicin (DOX) elicited cardiac dysfunction accompanied by increased production of reactive oxygen species and marked elevation of NOX1 mRNA in the heart. In mice deficient in Nox1 (Nox1), cardiac functions were well retained and overall survival was significantly improved. However, increased level of serum creatine kinase was equivalent to that of wild-type mice (Nox1). At 4 days after DOX treatment, severe cardiac fibrosis accompanied by increased hydroxyproline content and activation of matrix metalloproteinase-9 was demonstrated in Nox1, but it was significantly attenuated in Nox1. When H9c2 cardiomyocytes were exposed to their homogenate, a dose-dependent increase in NOX1 mRNA was observed. Up-regulation of NOX1 mRNA in H9c2 co-incubated with their homogenate was abolished in the presence of TAK242, a TLR4 inhibitor. When isolated cardiac fibroblasts were exposed to H9c2 homogenates, increased proliferation and up-regulation of collagen 3a1 mRNA were demonstrated. These changes were significantly attenuated in cardiac fibroblasts exposed to homogenates from H9c2 harboring disrupted Nox1. These findings suggest that up-regulation of NOX1 following cellular damage promotes cardiac dysfunction and fibrosis by aggravating the pro-fibrotic response of cardiac fibroblasts. Modulation of the NOX1/NADPH oxidase signaling pathway may be a novel therapeutic strategy for preventing heart failure after myocardial injury.
心肌纤维化是心力衰竭的常见特征，因此非常需要一种能够阻止纤维化进展的治疗策略。本文报道了一种非吞噬性超氧化物产生型 NADPH 氧化酶的 NOX1 同工酶，它在药物诱导的心肌损伤模型中促进心肌纤维化。单次给予多柔比星（DOX）可引起心脏功能障碍，伴随着活性氧的产生增加和心脏中 NOX1mRNA 的显著升高。在 Nox1 缺失（Nox1）的小鼠中，心脏功能得以很好地保留，总生存率显著提高。然而，血清肌酸激酶的水平增加与野生型小鼠（Nox1）相当。在 DOX 处理后 4 天，在 Nox1 中观察到严重的心肌纤维化，伴有羟脯氨酸含量增加和基质金属蛋白酶-9 的激活，但在 Nox1 中明显减轻。当 H9c2 心肌细胞暴露于其匀浆时，观察到 NOX1mRNA 呈剂量依赖性增加。在存在 TLR4 抑制剂 TAK242 的情况下，与 H9c2 共孵育的 H9c2 中 NOX1mRNA 的上调被消除。当分离的心肌成纤维细胞暴露于 H9c2 匀浆时，观察到细胞增殖增加和胶原 3a1mRNA 的上调。在暴露于携带破坏的 Nox1 的 H9c2 匀浆的成纤维细胞中，这些变化明显减轻。这些发现表明，细胞损伤后 NOX1 的上调通过加重心肌成纤维细胞的促纤维化反应来促进心脏功能障碍和纤维化。调节 NOX1/NADPH 氧化酶信号通路可能是预防心肌损伤后心力衰竭的一种新的治疗策略。
