Murtaza Ghulam, Mermer Petra, Goldenberg Anna, Pfeil Uwe, Paddenberg Renate, Weissmann Nobert, Lochnit Guenter, Kummer Wolfgang
Institute of Anatomy and Cell Biology, Justus-Liebig-University, Giessen, Germany.
Universities of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Germany.
PLoS One. 2017 Mar 16;12(3):e0174071. doi: 10.1371/journal.pone.0174071. eCollection 2017.
The two-pore domain potassium channel KCNK3 (TASK-1) is expressed in rat and human pulmonary artery smooth muscle cells. There, it is associated with hypoxia-induced signalling, and its dysfunction is linked to pathogenesis of human pulmonary hypertension. We here aimed to determine its role in hypoxic pulmonary vasoconstriction (HPV) in the mouse, and hence the suitability of this model for further mechanistic investigations, using appropriate inhibitors and TASK-1 knockout (KO) mice. RT-PCR revealed expression of TASK-1 mRNA in murine lungs and pre-acinar pulmonary arteries. Protein localization by immunohistochemistry and western blot was unreliable since all antibodies produced labelling also in TASK-1 KO organs/tissues. HPV was investigated by videomorphometric analysis of intra- (inner diameter: 25-40 μm) and pre-acinar pulmonary arteries (inner diameter: 41-60 μm). HPV persisted in TASK-1 KO intra-acinar arteries. Pre-acinar arteries developed initial HPV, but the response faded earlier (after 30 min) in KO vessels. This HPV pattern was grossly mimicked by the TASK-1 inhibitor anandamide in wild-type vessels. Hypoxia-provoked rise in pulmonary arterial pressure (PAP) in isolated ventilated lungs was affected neither by TASK-1 gene deficiency nor by the TASK-1 inhibitor A293. TASK-1 is dispensable for initiating HPV of murine intra-pulmonary arteries, but participates in sustained HPV specifically in pre-acinar arteries. This does not translate into abnormal rise in PAP. While there is compelling evidence that TASK-1 is involved in the pathogenesis of pulmonary arterial hypertension in humans, the mouse does not appear to serve as a suitable model to study the underlying molecular mechanisms.
双孔结构域钾通道KCNK3（TASK-1）在大鼠和人类肺动脉平滑肌细胞中表达。在这些细胞中，它与缺氧诱导的信号传导相关，其功能障碍与人类肺动脉高压的发病机制有关。我们在此旨在使用合适的抑制剂和TASK-1基因敲除（KO）小鼠，确定其在小鼠缺氧性肺血管收缩（HPV）中的作用，从而确定该模型用于进一步机制研究的适用性。逆转录聚合酶链反应（RT-PCR）显示TASK-1信使核糖核酸（mRNA）在小鼠肺和腺泡前肺动脉中表达。由于所有产生的抗体在TASK-1基因敲除的器官/组织中也产生标记，因此通过免疫组织化学和蛋白质印迹进行的蛋白质定位不可靠。通过对内径为25-40μm的肺内动脉和内径为41-60μm的腺泡前肺动脉进行视频形态分析来研究HPV。HPV在TASK-1基因敲除的肺内动脉中持续存在。腺泡前动脉出现初始HPV，但在基因敲除的血管中反应消退得更早（30分钟后）。野生型血管中的TASK-1抑制剂花生四烯乙醇胺大体上模拟了这种HPV模式。在离体通气肺中，缺氧引起的肺动脉压（PAP）升高既不受TASK-1基因缺陷的影响，也不受TASK-1抑制剂A293的影响。TASK-1对于启动小鼠肺内动脉的HPV不是必需的，但特别参与腺泡前动脉中持续的HPV。这不会转化为PAP的异常升高。虽然有令人信服的证据表明TASK-1参与人类肺动脉高压的发病机制，但小鼠似乎不是研究潜在分子机制的合适模型。
