Upregulation of Na+/Ca2+ exchanger and TRPC6 contributes to abnormal Ca2+ homeostasis in arterial smooth muscle cells from Milan hypertensive rats.
Upregulation of Na+/Ca2+ exchanger and TRPC6 contributes to abnormal Ca2+ homeostasis in arterial smooth muscle cells from Milan hypertensive rats.
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DOI：
10.1152/ajpheart.00356.2010
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发表时间：
2010-09
期刊：
影响因子：
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通讯作者：
A. Zulian;Sergey G. Baryshnikov;Cristina I. Linde;J. Hamlyn;P. Ferrari;V. Golovina
中科院分区：
文献类型：
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作者：
A. Zulian;Sergey G. Baryshnikov;Cristina I. Linde;J. Hamlyn;P. Ferrari;V. Golovina
大鼠的米兰高血压品系（MHS）是人类高血压的模型。在MHS大鼠中已经对肾功能的遗传缺陷进行了很好的研究，但是血管阻力升高的机制尚不清楚。Ca（2+）信号的改变在高血压相关的血管功能障碍中起着关键作用。在此，我们比较了MHS大鼠和正常血压大鼠（MNS）肠系膜动脉平滑肌细胞的Ca（2+）信号。MHS大鼠的收缩压高于MNS大鼠（144 +/- 2 vs. 113 +/- 1 mmHg，P < 0.05）。在MHS大鼠新鲜分离的动脉肌细胞中，静息胞浆游离Ca（2+）浓度（用Fura-2测量）和ATP诱导的Ca（2+）瞬变增加。在MHS中，由二酰基甘油类似物1-油酰基-2-乙酰基-sn-甘油激活的Ba（2+）内流（受体操纵通道活性的测量）比MNS动脉肌细胞大得多。这与瞬时受体电位典型6（TRPC 6）蛋白的三倍上调相关。TRPC 3，受体操作通道的另一个组成部分，是轻微的，但不显著，上调。TRPC 1/5的表达，组件的商店操作的渠道，没有改变MHS肠系膜动脉平滑肌。免疫印迹还显示，MHS肠系膜动脉中Na（+）/Ca（2+）交换器-1（NCX 1）的表达显著上调（约13倍），而质膜Ca（2+）-ATP酶的表达没有改变。通过去除细胞外Na（+）诱发的NCX 1反向模式的Ca（2+）内流诱导了胞浆游离Ca（2+）浓度的快速增加，这在MHS动脉肌细胞中显著更大。MHS肠系膜动脉α（1）/α（2）Na（+）泵的表达无变化。免疫细胞化学观察表明，NCX 1和TRPC 6聚集在质膜微区相邻的基础肌浆网。总之，MHS动脉表现出TRPC 6和NCX 1的上调以及Ca（2+）信号的增强。我们认为，增加的Ca（2+）信号参与了MHS大鼠血管收缩增强和血压升高。
The Milan hypertensive strain (MHS) of rats is a model for hypertension in humans. Inherited defects in renal function have been well studied in MHS rats, but the mechanisms that underlie the elevated vascular resistance are unclear. Altered Ca(2+) signaling plays a key role in the vascular dysfunction associated with arterial hypertension. Here we compared Ca(2+) signaling in mesenteric artery smooth muscle cells from MHS rats and its normotensive counterpart (MNS). Systolic blood pressure was higher in MHS than in MNS rats (144 +/- 2 vs. 113 +/- 1 mmHg, P < 0.05). Resting cytosolic free Ca(2+) concentration (measured with fura-2) and ATP-induced Ca(2+) transients were augmented in freshly dissociated arterial myocytes from MHS rats. Ba(2+) entry activated by the diacylglycerol analog 1-oleoyl-2-acetyl-sn-glycerol (a measure of receptor-operated channel activity) was much greater in MHS than MNS arterial myocytes. This correlated with a threefold upregulation of transient receptor potential canonical 6 (TRPC6) protein. TRPC3, the other component of receptor-operated channels, was marginally, but not significantly, upregulated. The expression of TRPC1/5, components of store-operated channels, was not altered in MHS mesenteric artery smooth muscle. Immunoblots also revealed that the Na(+)/Ca(2+) exchanger-1 (NCX1) was greatly upregulated in MHS mesenteric artery (by approximately 13-fold), whereas the expression of plasma membrane Ca(2+)-ATPase was not altered. Ca(2+) entry via the reverse mode of NCX1 evoked by the removal of extracellular Na(+) induced a rapid increase in cytosolic free Ca(2+) concentration that was significantly larger in MHS arterial myocytes. The expression of alpha(1)/alpha(2) Na(+) pumps in MHS mesenteric arteries was not changed. Immunocytochemical observations showed that NCX1 and TRPC6 are clustered in plasma membrane microdomains adjacent to the underlying sarcoplasmic reticulum. In summary, MHS arteries exhibit upregulated TRPC6 and NCX1 and augmented Ca(2+) signaling. We suggest that the increased Ca(2+) signaling contributes to the enhanced vasoconstriction and elevated blood pressure in MHS rats.