Modulation of p38 kinase by DUSP4 is important in regulating cardiovascular function under oxidative stress.
Modulation of p38 kinase by DUSP4 is important in regulating cardiovascular function under oxidative stress.
复制标题
DOI：
10.1016/j.freeradbiomed.2015.07.013
复制
发表时间：
2015-12
影响因子：
7.4
通讯作者：
Chen CA
中科院分区：
文献类型：
--
作者：
Barajas-Espinosa A;Basye A;Angelos MG;Chen CA
p38的过度激活与许多心血管疾病（CVD）有关，包括心肌梗死、肥大、心力衰竭和缺血性心脏病。CVD的许多治疗干预已经针对抑制p38丝裂原活化蛋白激酶活化，其有助于缺血/再灌注（I/R）损伤后的有害作用。然而，这些治疗方法的疗效远不理想，因为它们缺乏特异性并且与高毒性相关。以前，我们证明了N-乙酰半胱氨酸（NAC）预处理上调DUSP 4在内皮细胞中的表达，调节p38和ERK 1/2活性，从而提供抗氧化应激的保护作用。在这里，内皮细胞缺氧/复氧（H/R）的侮辱和孤立的心脏I/R损伤被用来调查的作用DUSP 4的p38通路的调制。在大鼠内皮细胞中，DUSP 4随H/R呈时间依赖性降解（2 h H/R后对照的0.25 ± 0.07倍变化）。其降解与p38的过度磷酸化（2.1 ± 0.36倍变化）和细胞凋亡密切相关，如裂解的caspase-3（12.59% ± 3.38%）或TUNEL标记（29.46% ± 3.75%）的免疫阳性细胞增加所示。在H/R期间，20 µM SB 203580抑制p38激酶活性可防止H/R诱导的细胞凋亡，通过TUNEL评估（12.99% ± 1.89%）。相反，DUSP 4基因沉默增加了内皮细胞对H/R诱导的凋亡的敏感性（45.81% ± 5.23%）。这种敏感性通过抑制p38活性而降低（总凋亡细胞降至17.47% ± 1.45%）。有趣的是，DUSP 4基因沉默有助于细胞产生超氧化物的增加。离体Langendorff灌注的小鼠心脏受到整体I/R损伤。DUSP 4 −/−心脏的梗死面积明显大于WT。DUSP 4 −/−小鼠中I/R诱导的梗死增加与功能恢复降低（通过RPP%、LVDP%、HR%和dP/dtmax评估）以及CF%降低和初始LVEDP升高显著相关。免疫印迹分析表明，在I/R损伤后，DUSP 4 −/−小鼠中p38明显过度活化。在WT和DUSP 4 −/− I/R心脏中均观察到裂解的caspase-3的激活。在缺血前和再灌注期间输注p38抑制剂可改善WT和DUSP 4 −/−心脏功能。因此，通过DUSP 4鉴定p38激酶调节为氧化剂诱导的疾病，特别是心肌梗死提供了新的治疗靶点。
Over-activation of p38 is implicated in many cardiovascular diseases (CVDs), including myocardial infarction, hypertrophy, heart failure, and ischemic heart disease. Numerous therapeutic interventions for CVDs have been directed towards the inhibition of the p38 mitogen-activated protein kinase activation that contributes to the detrimental effect after ischemia/reperfusion (I/R) injuries. However, the efficacy of these treatments is far from ideal as they lack specificity and are associated with high toxicity. Previously, we demonstrated that N-acetyl cysteine (NAC) pre-treatment up-regulates DUSP4 expression in endothelial cells, regulating p38 and ERK1/2 activities, thus providing a protective effect against oxidative stress. Here, endothelial cells under hypoxia/reoxygenation (H/R) insult and isolated heart I/R injury were used to investigate the role of DUSP4 on the modulation of the p38 pathway. In rat endothelial cells, DUSP4 is time-dependently degraded with H/R (0.25 ± 0.07 fold change of control after 2 h H/R). Its degradation is closely associated with hyper-phosphorylation of p38 (2.1 ± 0.36 fold change) and cell apoptosis, as indicated by the increase in cells immunopositive for cleaved caspase-3 (12.59% ± 3.38%) or TUNEL labeling (29.46% ± 3.75%). The inhibition of p38 kinase activity with 20 µM SB203580 during H/R prevents H/R-induced apoptosis, assessed via TUNEL (12.99% ± 1.89%). Conversely, DUSP4 gene silencing in endothelial cells augments their sensitivity to H/R-induced apoptosis (45.81% ± 5.23%). This sensitivity is diminished via the inhibition of p38 activity (total apoptotic cells drop to 17.47% ± 1.45%). Interestingly, DUSP4 gene silencing contributes to the increase in superoxide generation from cells. Isolated Langendorff-perfused mouse hearts were subjected to global I/R injury. DUSP4−/− hearts had significantly larger infarct size than WT. The increase in I/R-induced infarct in DUSP4−/− mice significantly correlates with reduced functional recovery (assessed by: RPP%, LVDP%, HR%, and dP/dtmax) as well as lower CF% and a higher initial LVEDP. From immunoblotting analysis, it is evident that p38 is significantly over-activated in DUSP4−/− mice after I/R injury. The activation of cleaved caspase-3 is seen in both WT and DUSP4−/− I/R hearts. Infusion of a p38 inhibitor prior to ischemia and during the reperfusion improves both WT and DUSP4−/− cardiac function. Therefore, the identification of p38 kinase modulation by DUSP4 provides a novel therapeutic target for oxidant-induced diseases, especially myocardial infarction.