Involvement of large conductance Ca2+-activated K+ channel in laminar shear stress-induced inhibition of vascular smooth muscle cell proliferation
Involvement of large conductance Ca2+-activated K+ channel in laminar shear stress-induced inhibition of vascular smooth muscle cell proliferation
复制标题
大电导Ca2+激活的K通道参与层流剪切应力诱导的血管平滑肌细胞增殖抑制
DOI：
10.1007/s00424-012-1182-z
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发表时间：
2013-02-01
影响因子：
4.5
通讯作者：
Fan, Yubo
中科院分区：
文献类型：
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作者：
Jia, Xiaoling;Yang, Jingyun;Fan, Yubo
血管平滑肌细胞（VSMC）的大电导钙激活钾通道（BK（Ca））是一种重要的钾通道，具有调节血管张力的作用。最近的研究表明，BK（Ca）通道功能的异常与细胞增殖的变化和血管疾病的发生有关。然而，直到今天，很少有报道表明该通道是否参与了VSMC对流体剪切应力（SS）的增殖反应。本研究探讨了BK（Ca）通道在层压应力下VSMC增殖中的可能作用。将大鼠主动脉VSMCs置于平行板流动室中，并以不同的持续时间和幅度暴露于层流SS。通过检测增殖细胞核抗原（PCNA）表达和DNA合成来评估VSMC增殖。流式细胞术和RT-PCR检测BK（Ca）蛋白和基因表达。BK（Ca）在SS诱导的增殖抑制中的参与通过使用BK（Ca）特异性阻断剂伊比利亚毒素（IBTX）的BK（Ca）抑制以及通过BK（Ca）转染BK（Ca）非表达CHO细胞来检查。[Ca（2+）]（i）的变化用钙敏感染料fluo 3-AM测定。用电位敏感染料DiBAC（4）（3）检测膜电位变化。我们发现，层状SS抑制VSMC增殖和刺激BK（Ca）通道的表达。此外，层状SS引起[Ca（2+）]（i）和膜超极化的增加。此外，在VSMC中，BK（Ca）通道活性对细胞增殖响应SS的抑制作用也在BK（Ca）转染的CHO细胞中得到证实，显示增殖下降。阻断BK（Ca）通道可逆转其抑制作用，为BK（Ca）参与SS诱导的增殖降低提供了额外的支持。我们的研究结果表明，第一次，BK（Ca）通道介导层SS诱导的VSMC增殖抑制。这一发现对于理解SS调节VSMC增殖的机制非常重要，并且应该有助于制定预防流动引发的血管疾病形成的策略。
The large conductance Ca(2+)-activated K(+) (BK(Ca)) channel in vascular smooth muscle cell (VSMC) is an important potassium channel that can regulate vascular tone. Recent work has demonstrated that abnormalities in BK(Ca) channel function are associated with changes in cell proliferation and the onset of vascular disease. However, until today there are rare reports to show whether this channel is involved in VSMC proliferation in response to fluid shear stress (SS). Here we investigated a possible role of BK(Ca) channel in VSMC proliferation under laminar SS. Rat aortic VSMCs were plated in parallel-plate flow chambers and exposed to laminar SS with varied durations and magnitudes. VSMC proliferation was assessed by measuring proliferating cell nuclear antigen (PCNA) expression and DNA synthesis. BK(Ca) protein and gene expression was determined by flow cytometery and RT-PCR. The involvement of BK(Ca) in SS-induced inhibition of proliferation was examined by BK(Ca) inhibition using a BK(Ca) specific blocker, iberiotoxin (IBTX), and by BK(Ca) transfection in BK(Ca) non-expressing CHO cells. The changes in [Ca(2+)](i) were determined using a calcium-sensitive dye, fluo 3-AM. Membrane potential changes were detected with a potential-sensitive dye, DiBAC(4)(3). We found that laminar SS inhibited VSMC proliferation and stimulated BK(Ca) channel expression. Furthermore, laminar SS induced an increase in [Ca(2+)](i) and membrane hyperpolarization. Besides in VSMC, the inhibitory effect of BK(Ca) channel activity on cell proliferation in response to SS was also confirmed in BK(Ca)-transfected CHO cells showing a decline in proliferation. Blocking BK(Ca) channel reversed its inhibitory effect, providing additional support for the involvement of BK(Ca) in SS-induced proliferation reduction. Our results suggest, for the first time, that BK(Ca) channel mediates laminar SS-induced inhibition of VSMC proliferation. This finding is important for understanding the mechanism by which SS regulates VSMC proliferation, and should be helpful in developing strategies to prevent flow-initiated vascular disease formation.