Helenius Mikko H, Vattulainen Sanna, Orcholski Mark, Aho Joonas, Komulainen Anne, Taimen Pekka, Wang Lingli, de Jesus Perez Vinicio A, Koskenvuo Juha W, Alastalo Tero-Pekka
Children's Hospital Helsinki, Pediatric Cardiology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland;
Division of Pulmonary and Critical Care Medicine, Stanford University, Stanford, California;
Am J Physiol Lung Cell Mol Physiol. 2015 May 15;308(10):L1046-57. doi: 10.1152/ajplung.00340.2014. Epub 2015 Mar 27.
Endothelial cell (EC) dysfunction plays a role in the pathobiology of occlusive vasculopathy in pulmonary arterial hypertension (PAH). Purinergic signaling pathways, which consist of extracellular nucleotide and nucleoside-mediated cell signaling through specific receptors, are known to be important regulators of vascular tone and remodeling. Therefore, we hypothesized that abnormalities in the vascular purinergic microenvironment are associated with PAH. Enzymatic clearance is crucial to terminate unnecessary cell activation; one of the most abundantly expressed enzymes on the EC surface is E-NTPDase1/CD39, which hydrolyzes ATP and ADP to AMP. we used histological samples from patients and healthy donors, radioisotope-labeled substrates to measure ectoenzyme activity, and a variety of in vitro approaches to study the role of CD39 in PAH. Immunohistochemistry on human idiopathic PAH (IPAH) patients' lungs demonstrated that CD39 was significantly downregulated in the endothelium of diseased small arteries. Similarly, CD39 expression and activity were decreased in cultured pulmonary ECs from IPAH patients. Suppression of CD39 in vitro resulted in EC phenotypic switch that gave rise to apoptosis-resistant pulmonary arterial endothelial cells and promoted a microenvironment that induced vascular smooth muscle cell migration. we also identified that the ATP receptor P2Y11 is essential for ATP-mediated EC survival. Furthermore, we report that apelin, a known regulator of pulmonary vascular homeostasis, can potentiate the activity of CD39 both in vitro and in vivo. we conclude that sustained attenuation of CD39 activity through ATP accumulation is tightly linked to vascular dysfunction and remodeling in PAH and could represent a novel target for therapy.
内皮细胞（EC）功能障碍在肺动脉高压（PAH）闭塞性血管病的病理生物学中起作用。嘌呤能信号通路由细胞外核苷酸和核苷通过特定受体介导的细胞信号组成，已知是血管张力和重塑的重要调节因子。因此，我们假设血管嘌呤能微环境异常与PAH相关。酶促清除对于终止不必要的细胞激活至关重要；EC表面表达最丰富的酶之一是E-NTPDase1/CD39，它将ATP和ADP水解为AMP。我们使用了患者和健康供体的组织学样本、放射性同位素标记的底物来测量外切酶活性，以及多种体外方法来研究CD39在PAH中的作用。对人类特发性PAH（IPAH）患者肺部的免疫组织化学分析表明，患病小动脉内皮中的CD39明显下调。同样，IPAH患者培养的肺EC中CD39的表达和活性降低。体外抑制CD39导致EC表型转换，产生抗凋亡的肺动脉内皮细胞，并促进诱导血管平滑肌细胞迁移的微环境。我们还发现ATP受体P2Y11对ATP介导的EC存活至关重要。此外，我们报告apelin是肺血管稳态的已知调节因子，在体外和体内均可增强CD39的活性。我们得出结论，通过ATP积累导致的CD39活性持续减弱与PAH中的血管功能障碍和重塑密切相关，可能代表一种新的治疗靶点。
