Berra-Romani Roberto, Raqeeb Abdul, Torres-Jácome Julián, Guzman-Silva Alejandro, Guerra Germano, Tanzi Franco, Moccia Francesco
Department of Biomedicine, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla, México.
J Vasc Res. 2012;49(1):65-76. doi: 10.1159/000329618. Epub 2011 Oct 11.
Endothelial injury is the primary event that leads to a variety of severe vascular disorders. Mechanical injury elicits a Ca(2+) response in the endothelium of excised rat aorta, which comprises an initial Ca(2+) release from inositol-1,4,5-trisphosphate (InsP(3))-sensitive stores followed by a long-lasting decay phase due to Ca(2+) entry through uncoupled connexons. The Ca(2+) signal may also adopt an oscillatory pattern, the molecular underpinnings of which are unclear. In the light of the role played by Ca(2+) spiking in tissue regeneration, this study aimed to unveil the mechanisms underlying injury-induced Ca(2+) oscillations. The latter reversibly ceased upon removal of extracellular Ca(2+) or addition of the gap junction blockers heptanol, 18 α,β-glycyrrhetinic acid, La(3+) and Ni(2+), but were insensitive to BTP-2 and SKF 96365. The spiking response was abolished by inhibiting the Ca(2+) entry mode of the Na(+)/Ca(2+) exchanger (NCX). The InsP(3)-producing agonist ATP resumed Ca(2+) oscillations in silent cells, while the phospholipase C inhibitor U73122 suppressed them. Injury-induced Ca(2+) transients were prevented by the sarcoplasmic-endoplasmic reticulum calcium ATPase (SERCA) blockers thapsigargin and cyclopiazonic acid, while they were unaffected by suramin and genistein. These data show for the first time that the coordinated interplay between NCX-mediated Ca(2+) entry and InsP(3)-dependent Ca(2+) release contributes to injury-induced intracellular Ca(2+) concentration oscillations.
内皮损伤是导致多种严重血管疾病的首要事件。机械损伤可引发大鼠离体主动脉内皮细胞的Ca(2+)反应，该反应包括最初从肌醇-1,4,5-三磷酸（InsP(3)）敏感储存库释放Ca(2+)，随后是由于Ca(2+)通过未偶联的连接子进入而导致的持久衰减阶段。Ca(2+)信号也可能呈现振荡模式，其分子基础尚不清楚。鉴于Ca(2+)尖峰在组织再生中的作用，本研究旨在揭示损伤诱导的Ca(2+)振荡的潜在机制。后者在去除细胞外Ca(2+)或添加间隙连接阻滞剂庚醇、18α,β-甘草次酸、La(3+)和Ni(2+)后可逆地停止，但对BTP-2和SKF 96365不敏感。通过抑制钠/钙交换器（NCX）的Ca(2+)进入模式可消除尖峰反应。产生InsP(3)的激动剂ATP可恢复静息细胞中的Ca(2+)振荡，而磷脂酶C抑制剂U73122可抑制它们。肌浆网-内质网钙ATP酶（SERCA）阻滞剂毒胡萝卜素和环匹阿尼酸可预防损伤诱导的Ca(2+)瞬变，而苏拉明和染料木黄酮对其无影响。这些数据首次表明，NCX介导的Ca(2+)进入与InsP(3)依赖性Ca(2+)释放之间的协同相互作用有助于损伤诱导的细胞内Ca(2+)浓度振荡。
