Wang Jichun, Hu Xiaorong, Xie Jing, Xu Weipan, Jiang Hong
Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute of Wuhan University, Wuhan, P. R. China.
Cell Physiol Biochem. 2015;35(2):767-77. doi: 10.1159/000369736. Epub 2015 Jan 30.
BACKGROUD/AIMS: The aim of the study was to evaluate the effects of beta1-adrenergic receptors (β1-ARs) -mediated nuclear factor erythroid 2-related factor 2 (Nrf2)-heme oxygenase-1 (HO-1)-high mobility group box 1 protein (HMGB1) axis regulation in hypoxia/reoxygenation (H/R)-induced neonatal rat cardiomyocytes.
The neonatal cultured cardiomyocytes were concentration-dependently pretreated by dobutamine (DOB), a selective β1-adrenergic receptor agonist, in the absence and/or presence of LY294002 (a phosphatidylinositol 3-kinase (PI3K) inhibitor), SB203580 (a p38mitogen-activated-protein kinase (p38MAPK) inhibitor), Nrf2siRNA and HO-1siRNA, respectively, and then treated by H/R. The effects and mechanisms by which H/R-induced cardiomyocytes injury were evaluated.
Significant increase of HO-1 was found in neonatal cultured cardiomyocytes treated with DOB, when compared to the control group. Significant change for Nrf2 translocation was also revealed in neonatal cultured cardiomyocytes treated with DOB. Insignificant decreases of NF-kappaB p65 activation and HMGB1 release were observed in H/R-induced neonatal cultured cardiomyocytes treated with DOB, when compared to the control group. Importantly, DOB treatment significantly increased the cell viability and decreased the levels of LDH and MDA in H/R-induced cardiomyocytes injury. However, DOB failed to increase HO-1, inhibit NF-kappaB p65 activation, prevent HMGB1 release and attenuate H/R-induced cardiomyocytes injury when the cultured cardiomyocytes were pretreated by Nrf2siRNA, HO-1siRNA, PI3K inhibitor (LY294002) and p38MAPK inhibitor (SB203580), respectively.
β1-ARs-mediated Nrf2-HO-1-HMGB1 axis regulation plays a critical protective role in H/R-induced neonatal rat cardiomyocytes injury in vitro via PI3K/p38MAPK signaling pathway.
背景/目的：本研究旨在评估β1-肾上腺素能受体（β1-ARs）介导的核因子红细胞2相关因子2（Nrf2）-血红素加氧酶-1（HO-1）-高迁移率族蛋白B1（HMGB1）轴调控在缺氧/复氧（H/R）诱导的新生大鼠心肌细胞中的作用。
将新生大鼠原代培养心肌细胞分别用选择性β1-肾上腺素能受体激动剂多巴酚丁胺（DOB）进行浓度依赖性预处理，同时和/或分别联合磷脂酰肌醇3激酶（PI3K）抑制剂LY294002、p38丝裂原活化蛋白激酶（p38MAPK）抑制剂SB203580、Nrf2小干扰RNA（Nrf2siRNA）和HO-1小干扰RNA（HO-1siRNA），然后进行H/R处理。评估H/R诱导的心肌细胞损伤的作用及机制。
与对照组相比，用DOB处理的新生大鼠原代培养心肌细胞中HO-1显著增加。用DOB处理的新生大鼠原代培养心肌细胞中Nrf2转位也有显著变化。与对照组相比，用DOB处理的H/R诱导的新生大鼠原代培养心肌细胞中NF-κB p65活化和HMGB1释放显著降低。重要的是，DOB处理显著提高了H/R诱导的心肌细胞损伤中的细胞活力，并降低了乳酸脱氢酶（LDH）和丙二醛（MDA）水平。然而，当原代培养心肌细胞分别用Nrf2siRNA、HO-1siRNA、PI3K抑制剂（LY294002）和p38MAPK抑制剂（SB203580）预处理后，DOB未能增加HO-1、抑制NF-κB p65活化、阻止HMGB1释放及减轻H/R诱导的心肌细胞损伤。
β1-ARs介导的Nrf2-HO-1-HMGB1轴调控通过PI3K/p38MAPK信号通路在体外对H/R诱导的新生大鼠心肌细胞损伤发挥关键保护作用。
