Ran Yajuan, Wu Hong, Wei Liuping, Yu Xiufeng, Chen Jianguo, Li Shanshan, Zhang Lei, Lou Jianshi, Zhu Daling
Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical University (Daqing) , Daqing Heilongjiang , China .
J Recept Signal Transduct Res. 2014 Aug;34(4):270-82. doi: 10.3109/10799893.2014.917322. Epub 2014 May 22.
Hypoxia activates nuclear factor of activated T cells isoforms c3 (NFATc3), a Ca(2+)-dependent transcription factor in murine pulmonary arteries (PAs), and NFATc3 has been proved to be implicated in hypoxia-induced pulmonary arterial smooth muscle cells (PASMCs) proliferation, but it remains unclear whether NFATc3 acts on the apoptosis of PASMCs, an important step in PAs remodeling. Our laboratory has demonstrated that 15-hydroxyeicosatetraenoic acid (15-HETE) is a key factor in hypoxia-induced PA remodeling and can increase PASMC intracellular Ca(2+) (Ca(2+)) in rats. It is possible that NFATc3 is related with the function of 15-HETE anti-apoptosis during hypoxia. Our results identified that NFATc3 was mainly localized in rat PASMCs and was upregulated in PAs during hypoxia-induced rat pulmonary hypertension (PH), while this effect was inhibited by administration of nordihydroguaiaretic acid (NDGA), a 15-lipoxygenase (15-LO) inhibitor. Moreover, hypoxia and exogenous 15-HETE promoted the expression and nuclear translocation of NFATc3 in PASMCs, which was inhibited by NDGA or small interfering RNA targeted to rat 15-LO1 or 15-LO2. Furthermore, endogenous 15-HETE induced by hypoxia and exogenous 15-HETE suppressed serum deprivation-induced loss of rat PASMCs survival and prevented annexin V binding, mitochondrial membrane potential depolarization, DNA nick end labeling and chromatin condensation. Although all these effects were suppressed after the cells were treated with cyclosporin A (a calcineurin/NFAT inhibitor), it aggravated the apoptosis induced by serum deprivation. Thus, all these results indicate that 15-HETE-mediated PASMCs anti-apoptosis in hypoxic PH via the Ca(2+)-NFATc3 pathway.
缺氧可激活小鼠肺动脉（PA）中钙依赖性转录因子——活化T细胞核因子异构体c3（NFATc3），且已证实NFATc3参与缺氧诱导的肺动脉平滑肌细胞（PASMC）增殖，但NFATc3是否作用于PASMC凋亡（这是PA重塑的重要步骤）尚不清楚。我们实验室已证明，15-羟基二十碳四烯酸（15-HETE）是缺氧诱导PA重塑的关键因素，且可增加大鼠PASMC细胞内钙离子浓度（[Ca²⁺]i）。在缺氧期间，NFATc3可能与15-HETE的抗凋亡功能有关。我们的研究结果表明，NFATc3主要定位于大鼠PASMC中，且在缺氧诱导的大鼠肺动脉高压（PH）期间PA中表达上调，而15-脂氧合酶（15-LO）抑制剂去甲二氢愈创木酸（NDGA）可抑制这一作用。此外，缺氧和外源性15-HETE可促进PASMC中NFATc3的表达及核转位，而NDGA或靶向大鼠15-LO1或15-LO2的小干扰RNA可抑制这一作用。此外，缺氧诱导的内源性15-HETE和外源性15-HETE可抑制血清剥夺诱导的大鼠PASMC存活丧失，并防止膜联蛋白V结合、线粒体膜电位去极化、DNA缺口末端标记和染色质凝聚。尽管在用环孢素A（一种钙调磷酸酶/NFAT抑制剂）处理细胞后所有这些作用均受到抑制，但它加重了血清剥夺诱导的细胞凋亡。因此，所有这些结果表明，15-HETE在缺氧性PH中通过Ca²⁺-NFATc3途径介导PASMC抗凋亡。
