Hong Zhigang, Cabrera Jésus A, Mahapatra Saswati, Kutty Shelby, Weir E Kenneth, Archer Stephen L
Department of Medicine, Queen's University, Etherington Hall, Room 3041, 94 Stuart St., Kingston, Ontario, K7L 3 N6, Canada.
J Mol Med (Berl). 2014 Sep;92(9):995-1007. doi: 10.1007/s00109-014-1162-1. Epub 2014 Jun 8.
Oxygen-induced contraction of the ductus arteriosus (DA) involves a mitochondrial oxygen sensor, which signals pO2 in the DA smooth muscle cell (DASMC) by increasing production of diffusible hydrogen peroxide (H2O2). H2O2 stimulates vasoconstriction by regulating ion channels and Rho kinase, leading to calcium influx and calcium sensitization. Because epidermal growth factor receptor (EGFR) signaling is also redox regulated and participates in oxygen sensing and vasoconstriction in other systems, we explored the role of the EGFR and its signaling cascade (p38 and c-Jun N-amino-terminal kinase (JNK)) in DA contraction. Experiments were performed in DA rings isolated from full-term New Zealand white rabbits and human DASMC. In human DASMCs, increasing pO2 from hypoxia to normoxia (40 to 100 mmHg) significantly increased cytosolic calcium, p < 0.01. This normoxic rise in intracellular calcium was mimicked by EGF and inhibited by EGFR siRNA. In DA rings, EGF caused contraction while the specific EGFR inhibitor (AG1478) and the tyrosine kinase inhibitors (genistein or tyrphostin A23) selectively attenuated oxygen-induced contraction (p < 0.01). Conversely, orthovanadate, a tyrosine phosphatase inhibitor known to activate EGFR signaling, caused dose-dependent contraction of hypoxic DA and superimposed increases in oxygen caused minimal additional contraction. Anisomycin, an activator of EGFR's downstream kinases, p38 and JNK, caused DA contraction; conversely, oxygen-induced DA contraction was blocked by inhibitors of p38 mitogen-activated protein kinases (MAPK) (SB203580) or JNK (JNK inhibitor II). O2-induced phosphorylation of EGFR occurred within 5 min of increasing pO2 and was inhibited by mitochondrial-targeted overexpression of catalase. AG1478 prevented the oxygen-induced p38 and JNK phosphorylation. In conclusion, O2-induced EGFR transactivation initiates p38/JNK-mediated increases in cytosolic calcium and contributes to DA contraction. The EGFR/p38/JNK pathway is regulated by mitochondrial redox signaling and is a promising therapeutic target for modulation of the patent ductus arteriosus.
Oxygen activates epidermal growth factor receptor (EGFR) in ductus arteriosus (DA) smooth muscle cells. EGFR inhibition selectively attenuates O2-induced DA constriction. pO2-induced EGFR activation is mediated by mitochondrial-derived hydrogen peroxide. p38 MAPK and JNK mediated EGFR's effects on oxygen-induced DA contraction. Tyrosine kinases and phosphatases participate in oxygen sensing in the DA. The EGFR pathway offers new therapeutic targets to modulate patency of the ductus arteriosus.
氧诱导的动脉导管（DA）收缩涉及一种线粒体氧传感器，该传感器通过增加可扩散的过氧化氢（H2O2）的产生来传递DA平滑肌细胞（DASMC）中的pO2。H2O2通过调节离子通道和Rho激酶刺激血管收缩，导致钙内流和钙敏化。由于表皮生长因子受体（EGFR）信号传导也受氧化还原调节，并参与其他系统中的氧感应和血管收缩，我们探讨了EGFR及其信号级联（p38和c-Jun氨基末端激酶（JNK））在DA收缩中的作用。实验在从足月新西兰白兔分离的DA环和人DASMC中进行。在人DASMC中，将pO2从低氧增加到常氧（40至100 mmHg）可显著增加细胞内钙，p <0.01。这种常氧下细胞内钙的升高可被表皮生长因子（EGF）模拟，并被EGFR小干扰RNA（siRNA）抑制。在DA环中，EGF引起收缩，而特异性EGFR抑制剂（AG1478）和酪氨酸激酶抑制剂（染料木黄酮或 tyrphostin A23）选择性减弱氧诱导的收缩（p <0.01）。相反，原钒酸盐是一种已知可激活EGFR信号传导的酪氨酸磷酸酶抑制剂，可引起低氧DA的剂量依赖性收缩，而氧增加引起的叠加收缩最小。茴香霉素是EGFR下游激酶p38和JNK的激活剂，可引起DA收缩；相反，氧诱导的DA收缩被p38丝裂原活化蛋白激酶（MAPK）抑制剂（SB203580）或JNK抑制剂（JNK inhibitor II）阻断。增加pO2后5分钟内发生O2诱导的EGFR磷酸化，并被过氧化氢酶的线粒体靶向过表达抑制。AG1478可防止氧诱导的p38和JNK磷酸化。总之，O2诱导的EGFR反式激活启动p38/JNK介导的细胞内钙增加，并导致DA收缩。EGFR/p38/JNK途径受线粒体氧化还原信号调节，是调节动脉导管未闭的有前景的治疗靶点。
氧激活动脉导管（DA）平滑肌细胞中的表皮生长因子受体（EGFR）。EGFR抑制选择性减弱O2诱导的DA收缩。pO2诱导的EGFR激活由线粒体衍生的过氧化氢介导。p38 MAPK和JNK介导EGFR对氧诱导的DA收缩的作用。酪氨酸激酶和磷酸酶参与DA中的氧感应。EGFR途径为调节动脉导管通畅提供了新的治疗靶点。
