Gao Weiwei, Shao Runxia, Zhang Xiaoping, Liu Daijian, Liu Ying, Fa Xian'en
Department of Respiratory Medicine; The Second Affiliated Hospital of Zhengzhou University, ZhengZhou 450014, Henan, China.
Department of Cardiovascular surgery; The Second Affiliated Hospital of Zhengzhou University, ZhengZhou 450014, Henan, China.
Exp Cell Res. 2017 Dec 1;361(1):192-198. doi: 10.1016/j.yexcr.2017.10.019. Epub 2017 Oct 22.
Pulmonary arterial hypertension (PAH), characterized by excessive proliferation and apoptosis resistance of pulmonary artery smooth muscle cells (PASMCs), is closely associated with the imbalance in vasoactive mediators and massive remodeling of pulmonary vasculature. DJ-1/park7, a multifunctional protein, plays a critical defense role in several cytobiological activity, such as transcriptional regulation, anti-oxidative stress and tumor formation. In this study, we investigated the effects of DJ-1 on hypoxia-induced PAH model rats and PASMCs, as well as its possible molecular mechanism. First, the low expressions of DJ-1 and caveolin-1 (Cav-1) were synchronously detected in lung tissue of PAH model rats and hypoxia-induced PASMCs by Western blot. Then, the DJ-1 wild type (WT) or Knock out (KO) rats were exposed to chronic hypoxia to mimic a hypoxic PAH condition. The protein level of Cav-1 was markedly decreased in the tissue of DJ-1 KO rats, and additionally lower in tissue of the hypoxia group than that in the normoxia group for DJ-1 WT and KO rats. In vivo, hemodynamic data showed that the pulmonary arterial pressure (mPAP), right ventricle systolic pressure (RVSP) and pulmonary arterial systolic pressure (PASP), as well as the weight of the right ventricle/left ventricle plus septum (RV/LV+S) ratio of PAH model rats were higher in the DJ-1 KO group than those in the DJ-1 WT group. Moreover, knockout of DJ-1 also results in the phenotype switch from contractile to synthetic PASMC, which is reflected by reduced calponin and SM22α expressions. In vitro, DJ-1 overexpression reversed hypoxia-induced elevation of PASMC cell proliferation, migration and Ca concentration, which were not obviously observed in Cav-1 shRNA (sh-Cav-1) and DJ-1 co-transfected cells. Then the increased levels of calponin and SM22α were detected in the DJ-1 group; similarly those levels were not changed in the DJ-1+sh-Cav-1 group. Finally, the expression of TGFβ1, p-Smad2 and p-Smad3 were obviously decreased in the ad-DJ-1 group, however those were all elevated in the DJ-1 and sh-Cav-1 co-transfected groups. In conclusion, these results indicate that DJ-1 may alleviate hypoxia-induced PASMCs injury by Cav-1 through inhibiting the TGFβ/Smad signaling pathway.
肺动脉高压（PAH）的特征是肺动脉平滑肌细胞（PASMCs）过度增殖和抗凋亡，与血管活性介质失衡及肺血管大规模重塑密切相关。DJ-1/park7是一种多功能蛋白，在多种细胞生物学活性中发挥关键防御作用，如转录调控、抗氧化应激和肿瘤形成。在本研究中，我们探究了DJ-1对缺氧诱导的PAH模型大鼠和PASMCs的影响及其可能的分子机制。首先，通过蛋白质印迹法同步检测到PAH模型大鼠肺组织和缺氧诱导的PASMCs中DJ-1和小窝蛋白-1（Cav-1）表达降低。然后，将DJ-1野生型（WT）或敲除（KO）大鼠暴露于慢性缺氧环境以模拟缺氧性PAH状态。DJ-1 KO大鼠组织中Cav-1蛋白水平显著降低，并且对于DJ-1 WT和KO大鼠，缺氧组组织中的Cav-1蛋白水平低于常氧组。在体内，血流动力学数据显示，DJ-1 KO组PAH模型大鼠的肺动脉压（mPAP）、右心室收缩压（RVSP）和肺动脉收缩压（PASP），以及右心室重量/左心室加室间隔重量（RV/LV+S）比值均高于DJ-1 WT组。此外，敲除DJ-1还导致PASMC从收缩型向合成型表型转变，这通过钙调蛋白和SM22α表达降低得以体现。在体外，DJ-1过表达逆转了缺氧诱导的PASMC细胞增殖、迁移和钙浓度升高，而在Cav-1短发夹RNA（sh-Cav-1）与DJ-1共转染的细胞中未明显观察到这种逆转。然后在DJ-1组中检测到钙调蛋白和SM22α水平升高；类似地，在DJ-1+sh-Cav-1组中这些水平未发生变化。最后，在腺病毒-DJ-1（ad-DJ-1）组中TGFβ1、p-Smad2和p-Smad3的表达明显降低，然而在DJ-1与sh-Cav-1共转染组中这些表达均升高。总之，这些结果表明DJ-1可能通过Cav-1抑制TGFβ/Smad信号通路减轻缺氧诱导的PASMCs损伤。
