一氧化氮通过减少肌内皮钙信号传播增强内皮反应性：连接蛋白37（Cx37）和蛋白酪氨酸磷酸酶SHP-2的新作用。

NO Augments Endothelial Reactivity by Reducing Myoendothelial Calcium Signal Spreading: A Novel Role for Cx37 (Connexin 37) and the Protein Tyrosine Phosphatase SHP-2.

作者信息

Pogoda Kristin, Mannell Hanna, Blodow Stephanie, Schneider Holger, Schubert Kai Michael, Qiu Jiehua, Schmidt Andreas, Imhof Axel, Beck Heike, Tanase Laurentia Irina, Pfeifer Alexander, Pohl Ulrich, Kameritsch Petra

机构信息

From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.).

出版信息

Arterioscler Thromb Vasc Biol. 2017 Dec;37(12):2280-2290. doi: 10.1161/ATVBAHA.117.309913. Epub 2017 Oct 12.

DOI:10.1161/ATVBAHA.117.309913

PMID:29025706

Abstract

OBJECTIVE

Because of its strategic position between endothelial and smooth muscle cells in microvessels, Cx37 (Connexin 37) plays an important role in myoendothelial gap junctional intercellular communication. We have shown before that NO inhibits gap junctional intercellular communication through gap junctions containing Cx37. However, the underlying mechanism is not yet identified.

APPROACH AND RESULTS

Using channel-forming Cx37 mutants exhibiting partial deletions or amino acid exchanges in their C-terminal loops, we now show that the phosphorylation state of a tyrosine residue at position 332 (Y332) in the C-terminus of Cx37 controls the gap junction-dependent spread of calcium signals. Mass spectra revealed that NO protects Cx37 from dephosphorylation at Y332 by inhibition of the protein tyrosine phosphatase SHP-2. Functionally, the inhibition of gap junctional intercellular communication by NO decreased the spread of the calcium signal (induced by mechanical stimulation of individual endothelial cells) from endothelial to smooth muscle cells in intact vessels, while, at the same time, augmenting the calcium signal spreading within the endothelium. Consequently, preincubation of small resistance arteries with exogenous NO enhanced the endothelium-dependent dilator response to acetylcholine in spite of a pharmacological blockade of NO-dependent cGMP formation by the soluable guanylyl cyclase inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one).

CONCLUSIONS

Our results identify a novel mechanism by which NO can increase the efficacy of calcium, rising vasoactive agonists in the microvascular endothelium.

摘要

目的

由于Cx37（连接蛋白37）在微血管内皮细胞和平滑肌细胞之间的战略位置，其在肌内皮间隙连接细胞间通讯中发挥着重要作用。我们之前已经表明，一氧化氮（NO）通过含有Cx37的间隙连接抑制间隙连接细胞间通讯。然而，其潜在机制尚未明确。

方法与结果

使用在其C末端环中表现出部分缺失或氨基酸交换的形成通道的Cx37突变体，我们现在表明Cx37 C末端第332位酪氨酸残基（Y332）的磷酸化状态控制着钙信号的间隙连接依赖性传播。质谱分析表明，NO通过抑制蛋白酪氨酸磷酸酶SHP-2保护Cx37在Y332处不被去磷酸化。在功能上，NO对间隙连接细胞间通讯的抑制减少了完整血管中钙信号（由单个内皮细胞的机械刺激诱导）从内皮细胞到平滑肌细胞的传播，同时增强了钙信号在内皮内的传播。因此，尽管可溶性鸟苷酸环化酶抑制剂ODQ（1H-[1,2,4]恶二唑并[4,3-a]喹喔啉-1-酮）对NO依赖性环鸟苷酸（cGMP）形成进行了药理学阻断，但用外源性NO预孵育小阻力动脉增强了对乙酰胆碱的内皮依赖性舒张反应。