Realtime imaging analysis of tyrosine phosphorylation in response to hemodynamic forces

<Purpose>包括血管和心脏在内的心血管系统总是受到诸如血压和血流量等血液动力学应力的影响。我们研究了血管组织的机械转导机制，特别考虑到酪氨酸激酶，蛋白激酶C和Rho/Rho激酶系统的相互作用。（<Results and Discussion>1）机械力传感分子的药理学特性我们研究了机械力向细胞内信号转化的两条途径。1)钆离子敏感性牵张激活阳离子通道（SA）：犬脑动脉对牵张的肌源性收缩是通过以下过程启动的：SA通道激活使膜去极化，随后通过L型Ca通道发生胞浆Ca增加，导致Ca激活的CI通道开放，CI流出进一步使膜去极化。2)RGD肽敏感整合素：伸展 关于我们 诱导20 kd肌球蛋白轻链的多重磷酸化，具有低肌张力。酪氨酸激酶、蛋白激酶C和Rho/Rho激酶系统的相互作用对产生这种多重磷酸化特别重要。此外，我们发现，RGD-肽敏感和不敏感的途径参与牵张诱导的生产血管收缩剂前列腺素类，包括未转化的胰高血糖素H2，在兔肺动脉内皮细胞。(2)机械力传导的时间药理学脑腔内压力升高引起大鼠脑动脉时相性和强直性肌源性收缩。Rho/Rho激酶参与了阶段性和紧张性反应，而蛋白激酶C在肌源性收缩的紧张性阶段发挥了作用。这两种激酶似乎作为一个钙致敏剂的生肌机制。(3)机械传导的超生理学方面1）肺动脉高压：低压缺氧诱导的小鼠肺动脉高压。肺动脉高压时肺动脉可能过度伸展。因此，细胞外信号调节蛋白激酶（ERK 1/2），机械转导的指标，小鼠肺被特异性激活。2)蛛网膜下腔出血（CVS）后的脑血管痉挛：CVS被认为是由红细胞来源的氧合血红蛋白（一种氧应激剂）引起的。我们注意到CVS之间的相关性和收缩和其他反应的机械应力方面的功能作用的酪氨酸激酶，蛋白激酶C，和Rho/Rho激酶系统。因此，对心血管系统中机械力传导的研究有助于阐明心血管疾病中血管痉挛发作和病理性重构的发生机制，并具有潜在的治疗意义。少

<Purpose> Cardiovascular systems including blood vessels and heart are always subjected to hemodynamic stresses such as blood pressure and blood flow. We studied the mechanism of mechanotransduction of vascular tissues with special regard to the interactive role of tyrosine kinase, protein kinase C, and Rho/Rho kinase systems. We summarize herewith our results as following:<Results and Discussion> (1) Pharmacological characteristics of mechanosensor moleculesWe investigated two pathways transforming mechanical force to intracellular signaling. 1) Gadolinium ion-sensitive stretch-activated cation channel (SA): Myogenic contraction of canine cerebral artery in response to stretch was initiated by the following process; membrane was depolarized by activation of SA channel, and subsequent increase in cytosolic Ca occurred through L-type Ca channel, which led to opening of Ca-activated CI channel, and efflux of CI further depolarized the membrane. 2) RGD-peptide sensitive integrin: Stretch … More induced multiple phosphorylation of 20kd myosin light chain with low myogenic tone. The interactive role of tyrosine kinase, protein kinase C, and Rho/Rho kinase systems are in particular of importance to produce this multiple phosphorylation. Furthermore, we found that RGD-peptide sensitive and -insensitive pathways were involved in stretch-induced production of vasoconstrictor prostanoids, including untransformed prostaglandinH2, in rabbit pulmonary artery with endothelium.(2) Chronophamacology of mechanotransductionIncrease in intraluminal pressure produced phasic and tonic myogenic contraction of rat cerebral artery. Rho/Rho kinase was involved in both phasic and tonic responses, whereas protein kinase C played a role in the tonic phase of myogenic contraction. Both kinases seem to act as a Ca sensitizer in the myogenic mechanism.(3) Pasthophysiological aspects of mechanotransduction1) Pulmonary hypertension: Hypobaric hypoxia induced pulmonary hypertension in mice. It is possible that pulmonary arteries are stretched excessively in pulmonary hypertension. Consequently, extracellular signal-regulated protein kinase (ERK1/2), an index of mechanotransduction, of murine lung was specifically activated. 2) Cerebral vasospasm after subarachnoid hemorrhage (CVS): CVS is considered to be elicited by erythrocyte-derived oxyhemoglobin, an oxygen stresser. We notice the relevance between CVS and the contractile and other responses to mechano-stress in terms of functional roles of tyrosine kinase, protein kinase C, and Rho/Rho kinase systems. Thus, the study of the mechanotransduction in cardiovascular system surely aids in clarifying the mechanisms underlying vasospastic episodes and the initiation of pathologic remodeling in cardiovascular diseases, and potentially has therapeutic consequences. Less