Boittin François-Xavier, Alonso Florian, Le Gal Loïc, Allagnat Florent, Bény Jean-Louis, Haefliger Jacques-Antoine
Department of Zoology and Animal Biology, Laboratory of Vascular Cell Physiology, University of Geneva, Geneva 4, Switzerland.
Cell Physiol Biochem. 2013;31(1):166-78. doi: 10.1159/000343358. Epub 2013 Feb 1.
BACKGROUND/AIMS: Smooth muscle tone is controlled by Ca(2+) signaling in the endothelial layer. Mouse endothelial cells are interconnected by gap junctions made of Connexin40 (Cx40) and Cx37, which allow the exchange of signaling molecules to coordinate their activity. Here, we investigated the role of Cx40 in the endothelial Ca(2+) signaling of the mouse aorta.
Ca(2+) imaging was performed on intact aortic endothelium from both wild type (Cx40+/+) and Connexin40-deficient (Cx40 -/-) mice.
Acetylcholine (ACh) induced early fast and high amplitude Ca(2+) transients in a fraction of endothelial cells expressing the M3 muscarinic receptors. Inhibition of intercellular communication using carbenoxolone or octanol fully blocked the propagation of ACh-induced Ca(2+) transients toward adjacent cells in WT and Cx40-/- mice. As compared to WT, Cx40-/- mice displayed a reduced propagation of ACh-induced Ca(2+) waves, indicating that Cx40 contributes to the spreading of Ca(2+) signals. The propagation of those Ca(2+) responses was not blocked by suramin, a blocker of purinergic ATP receptors, indicating that there is no paracrine effect of ATP release on the Ca(2+) waves.
Altogether our data show that Cx40 and Cx37 contribute to the propagation and amplification of the Ca(2+) signaling triggered by ACh in endothelial cells expressing the M3 muscarinic receptors.
背景/目的：平滑肌张力受内皮细胞层中Ca(2+)信号传导的控制。小鼠内皮细胞通过由连接蛋白40（Cx40）和Cx37构成的缝隙连接相互连接，这些缝隙连接允许信号分子交换以协调它们的活性。在此，我们研究了Cx40在小鼠主动脉内皮细胞Ca(2+)信号传导中的作用。
对野生型（Cx40+/+)和连接蛋白40缺陷型（Cx40 -/-）小鼠的完整主动脉内皮进行Ca(2+)成像。
乙酰胆碱（ACh）在一部分表达M3毒蕈碱受体的内皮细胞中诱导早期快速且高幅度的Ca(2+)瞬变。使用羧苄青霉素或辛醇抑制细胞间通讯完全阻断了WT和Cx40-/-小鼠中ACh诱导的Ca(2+)瞬变向相邻细胞的传播。与WT相比，Cx40-/-小鼠中ACh诱导的Ca(2+)波的传播减少，表明Cx40有助于Ca(2+)信号的扩散。这些Ca(2+)反应的传播未被嘌呤能ATP受体阻滞剂苏拉明阻断，表明ATP释放对Ca(2+)波没有旁分泌作用。
我们的数据总体表明，Cx40和Cx37有助于在表达M3毒蕈碱受体的内皮细胞中由ACh触发的Ca(2+)信号传导的传播和放大。
