ROLE OF G-PROTEINS IN SHEAR STRESS-MEDIATED NITRIC-OXIDE PRODUCTION BY ENDOTHELIAL-CELLS
ROLE OF G-PROTEINS IN SHEAR STRESS-MEDIATED NITRIC-OXIDE PRODUCTION BY ENDOTHELIAL-CELLS
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DOI：
10.1152/ajpcell.1994.267.3.c753
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发表时间：
1994-09-01
影响因子：
--
通讯作者：
FRANGOS, JA
中科院分区：
文献类型：
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作者：
KUCHAN, MJ;JO, H;FRANGOS, JA
培养的内皮细胞暴露于流体流动产生的剪应力下，可刺激一氧化氮(NO)的产生。我们已经确定，在最初的产量暴增之后，持续的稳定状态下不生产。导致这种刺激的信号转导事件还不是很清楚。在本研究中，我们研究了调节鸟嘌呤核苷酸结合蛋白(G蛋白)在切应力介导的NO产生中的作用。在未暴露于切应力的内皮细胞中，G蛋白的通用激活剂AIF(4)(-)显著增加了鸟苷3‘，5’-环一磷酸(CGMP)的产生。NO合酶抑制剂N-omega-硝基-L-精氨酸可完全阻断这种刺激。与普通G蛋白抑制剂鸟苷5‘-O-(2-硫代二磷酸)(GDPbeta S)孵育后，cGMP的产生呈剂量依赖性地被阻断。同样，国内生产总值βS对NOx(NO_2+NO_3)的生成有抑制作用，但在1~3小时内未发现抑制作用，百日咳毒素对各时间点的剪切反应均无影响。由切应力变化引起的NO产生的暴发似乎依赖于一种对PTX不敏感的G蛋白。持续剪切介导的产物不依赖于G蛋白的激活。
Exposure of cultured endothelial cells to shear stress resulting from well-defined fluid flow stimulates the production of nitric oxide (NO). We have established that an initial burst in production is followed by sustained steady-state NO production. The signal transduction events leading to this stimulation are not well understood. In the present study, we examined the role of regulatory guanine nucleotide binding proteins (G proteins) in shear stress-mediated NO production. In endothelial cells not exposed to shear stress, AIF(4)(-), a general activator of G proteins, markedly elevated the production of guanosine 3',5'-cyclic monophosphate (cGMP). Pretreatment with NO synthase inhibitor N-omega-nitro-L-arginine completely blocked this stimulation. Incubation with guanosine 5'-O-(2-thiodiphosphate) (GDP beta S), a general G protein inhibitor, blocked the flow-mediated burst in cGMP production in a dose-dependent manner. Likewise, GDP beta S inhibited NOx(NO2 + NO3) production for the 1st h. However, inhibition was not detectable between 1 and 3 h. Pertussis toxin (PTx) had no effect on the shear response at any time point. The burst in NO production caused by a change in shear stress appears to be dependent on a PTx-refractory G protein. Sustained shear-mediated production is independent of G protein activation.