NO Augments Endothelial Reactivity by Reducing Myoendothelial Calcium Signal Spreading: A Novel Role for Cx37 (Connexin 37) and the Protein Tyrosine Phosphatase SHP-2
NO Augments Endothelial Reactivity by Reducing Myoendothelial Calcium Signal Spreading: A Novel Role for Cx37 (Connexin 37) and the Protein Tyrosine Phosphatase SHP-2
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DOI：
10.1161/atvbaha.117.309913
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发表时间：
2017-12
期刊：
影响因子：
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通讯作者：
K. Pogoda;H. Mannell;Stephanie Blodow;Holger Schneider;K. Schubert;Jiehua Qiu;A. Schmidt;A. Imhof;H. Beck;L. Tanase;A. Pfeifer;U. Pohl;P. Kameritsch
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作者：
K. Pogoda;H. Mannell;Stephanie Blodow;Holger Schneider;K. Schubert;Jiehua Qiu;A. Schmidt;A. Imhof;H. Beck;L. Tanase;A. Pfeifer;U. Pohl;P. Kameritsch
目的-由于其在微血管内皮细胞和平滑肌细胞之间的重要位置，Cx37 （Connexin 37）在肌内皮间隙连接细胞间通讯中起重要作用。我们之前已经证明，NO通过含有Cx37的间隙连接抑制间隙连接的细胞间通讯。然而，潜在的机制尚未确定。方法和结果-利用在其c端环中表现出部分缺失或氨基酸交换的通道形成的Cx37突变体，我们现在表明Cx37 c端332位酪氨酸残基（Y332）的磷酸化状态控制着钙信号依赖于间隙连接的传播。质谱显示NO通过抑制蛋白酪氨酸磷酸酶SHP-2来保护Cx37在Y332位点的去磷酸化。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）从内皮细胞向平滑肌细胞的传播，同时增加了钙信号在内皮细胞内的传播。因此，外源性NO对小阻力动脉的预孵育增强了内皮依赖性扩张剂对乙酰胆碱的反应，尽管可溶的guanyyl环化酶抑制剂ODQ （1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one）可以阻断NO依赖性cGMP的形成。结论-我们的研究结果确定了一种新的机制，通过该机制NO可以增加钙的功效，增加微血管内皮中的血管活性激动剂。
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.