Airway smooth muscle tone increases actin filamentogenesis and contractile capacity.
Airway smooth muscle tone increases actin filamentogenesis and contractile capacity.
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气道平滑肌张力增加肌动蛋白丝生成和收缩能力。
DOI：
10.1152/ajplung.00205.2019
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Bossé,Ynuk
中科院分区：
文献类型：
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作者：
Gazzola,Morgan;Henry,Cyndi;Lortie,Katherine;Khadangi,Fatemeh;Park,ChanYoung;Fredberg,JeffreyJ;Bossé,Ynuk
气道平滑肌（ASM）的力适应是一个过程，借此张力的存在（即，持续收缩）增加收缩能力。例如，在健康小鼠和人类中，音调已被证明会增加气道反应性。本研究的目的是阐明潜在的分子机制。小鼠气管产生的最大力是在10− 4 M乙酰甲胆碱作用30分钟后测量的，有或没有乙酰甲胆碱EC 30引起的张力。为了确认在细胞水平上发生力适应，还按照类似的方案测量了由培养的人ASM细胞产生的牵引力。使用不同的药理学抑制剂来研究Rho相关的卷曲螺旋蛋白激酶（ROCK）、蛋白激酶C（PKC）、肌球蛋白轻链激酶（MLCK）和肌动蛋白聚合在力适应中的作用。还定量了肌球蛋白的调节轻链（RLC）的磷酸化水平、肌动蛋白丝的量和肌动蛋白切割蛋白cofilin的活化水平。虽然ROCK，PKC，MLCK和RLC磷酸化没有牵连，力适应被阻止抑制肌动蛋白聚合。有趣的是，音调的存在除了将肌动蛋白丝的量增加到最大水平之外，还阻断了cofilin的激活。我们的结论是，肌动蛋白filamentogenesis引起的音调，从肌动蛋白聚合和cofilin介导的肌动蛋白裂解的预防，是主要的分子机制的力适应。
Force adaptation of airway smooth muscle (ASM) is a process whereby the presence of tone (i.e., a sustained contraction) increases the contractile capacity. For example, tone has been shown to increase airway responsiveness in both healthy mice and humans. The goal of the present study is to elucidate the underlying molecular mechanisms. The maximal force generated by mouse tracheas was measured in response to 10−4M of methacholine following a 30-min period with or without tone elicited by the EC30of methacholine. To confirm the occurrence of force adaptation at the cellular level, traction force generated by cultured human ASM cells was also measured following a similar protocol. Different pharmacological inhibitors were used to investigate the role of Rho-associated coiled-coil containing protein kinase (ROCK), protein kinase C (PKC), myosin light chain kinase (MLCK), and actin polymerization in force adaptation. The phosphorylation level of the regulatory light chain (RLC) of myosin, the amount of actin filaments, and the activation level of the actin-severing protein cofilin were also quantified. Although ROCK, PKC, MLCK, and RLC phosphorylation was not implicated, force adaptation was prevented by inhibiting actin polymerization. Interestingly, the presence of tone blocked the activation of cofilin in addition to increasing the amount of actin filaments to a maximal level. We conclude that actin filamentogenesis induced by tone, resulting from both actin polymerization and the prevention of cofilin-mediated actin cleavage, is the main molecular mechanism underlying force adaptation.