Phospholipase C-δ1 modulates sustained contraction of rat mesenteric small arteries in response to noradrenaline, but not endothelin-1
Phospholipase C-δ1 modulates sustained contraction of rat mesenteric small arteries in response to noradrenaline, but not endothelin-1
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DOI：
10.1152/ajpheart.01396.2007
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发表时间：
2008-08-01
影响因子：
4.8
通讯作者：
Ohanian, Jacqueline
中科院分区：
文献类型：
--
作者：
Clarke, Christopher J.;Forman, Simon;Ohanian, Jacqueline
血管收缩剂激活磷脂酶C (PLC)，其水解磷脂酰肌醇4,5-二磷酸（PIP2），导致钙动员，蛋白激酶C激活和收缩。我们的目的是研究PLC- δ(1)是否参与去甲肾上腺素（NA）或内皮素（ET-1）诱导的PIP2水解和收缩。PLC- δ(1)是一种与α(1)-肾上腺素受体信号传导和高血压发病有关的PLC亚型。研究大鼠肠系膜小动脉。用压力肌图测定收缩力，用（33）Pi或myo-[(3)H]肌醇放射性标记法测定磷脂或肌醇磷酸，用不连续蔗糖密度离心法制备小泡/筏。PLC-delta(1)通过免疫印迹分析被定位，并通过输送PLC-delta(1)抗体被中和。PLC抑制剂U73122显著抑制NA和ET-1的收缩，而阴性对照U-73342不影响钾和磷酯的收缩，暗示PLC活性参与受体介导的平滑肌收缩。PLC-delta(1)存在于小泡/筏中，NA（而不是ET-1）刺激这些区域的PLC-delta(1)水平快速增加两倍。PLC-delta(1)是钙依赖的，细胞外钙的去除阻止了它在NA作用下与小泡/筏的结合，同时减少了NA诱导的[(33)P] PIP2水解和[(3)H]肌醇磷酸的形成，但对et -1诱导的[(33)P] PIP2水解没有影响。与对照抗体相比，PLC-delta(1)抗体中和PLC-delta(1)可阻止其小窝/筏关联，并减弱对NA的持续收缩反应。相反，et -1诱导的收缩不受PLC-delta(1)抗体的影响。这些结果表明，在完整的维管组织中，小泡/筏定位的PLC-delta(1)在na诱导的PIP2水解和持续收缩中具有新颖的选择性作用。
Vasoconstrictors activate phospholipase C (PLC), which hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2), leading to calcium mobilization, protein kinase C activation, and contraction. Our aim was to investigate whether PLC-delta(1), a PLC isoform implicated in alpha(1)-adrenoreceptor signaling and the pathogenesis of hypertension, is involved in noradrenaline (NA) or endothelin (ET-1)-induced PIP2 hydrolysis and contraction. Rat mesenteric small arteries were studied. Contractility was measured by pressure myography, phospholipids or inositol phosphates were measured by radiolabeling with (33)Pi or myo-[(3)H] inositol, and caveolae/rafts were prepared by discontinuous sucrose density centrifugation. PLC-delta(1) was localized by immunoblot analysis and neutralized by delivery of PLC-delta(1) antibody. The PLC inhibitor U73122, but not the negative control U-73342, markedly inhibited NA and ET-1 contraction but had no effect on potassium or phorbol ester contraction, implicating PLC activity in receptor-mediated smooth muscle contraction. PLC-delta(1) was present in caveolae/rafts, and NA, but not ET-1, stimulated a rapid twofold increase in PLC-delta(1) levels in these domains. PLC-delta(1) is calcium dependent, and removal of extracellular calcium prevented its association with caveolae/rafts in response to NA, concomitantly reducing NA-induced [(33)P] PIP2 hydrolysis and [(3)H] inositol phosphate formation but with no effect on ET-1-induced [(33)P] PIP2 hydrolysis. Neutralization of PLC-delta(1) by PLC-delta(1) antibody prevented its caveolae/raft association and attenuated the sustained contractile response to NA compared with control antibodies. In contrast, ET-1-induced contraction was not affected by PLC-delta(1) antibody. These results indicate the novel and selective role of caveolae/raft localized PLC-delta(1) in NA-induced PIP2 hydrolysis and sustained contraction in intact vascular tissue.