Pregnancy-enhanced store-operated Ca2+ channel function in uterine artery endothelial cells is associated with enhanced agonist-specific transient receptor potential channel 3-inositol 1,4,5-trisphosphate receptor 2 interaction
Pregnancy-enhanced store-operated Ca2+ channel function in uterine artery endothelial cells is associated with enhanced agonist-specific transient receptor potential channel 3-inositol 1,4,5-trisphosphate receptor 2 interaction
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DOI：
10.1677/joe.1.06773
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发表时间：
2006-08-01
影响因子：
4
通讯作者：
Bird, Ian M.
中科院分区：
文献类型：
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作者：
Gifford, Shannon M.;Yi, Fu-Xian;Bird, Ian M.
我们之前已经表明，内皮细胞（EC）来源于子宫动脉（UA）的怀孕（P-UAEC）和非怀孕（NP-UAEC）母羊在ATP刺激后表现出双相细胞内游离Ca2+ ([Ca2+](i))反应。在每种情况下，由细胞内Ca2+储存的Ca2+释放引起的初始瞬时峰值是由嘌呤能受体- y2介导的，并且在两种细胞类型中非常相似。然而，由细胞外Ca2+流入引起的持续期在P-UAEC中升高，并与细胞通过储存操作通道（soc）表现出增强的容性Ca2+进入（CCE）的能力增加有关。在这里，我们证明了持续[Ca2+](i)响应的差异维持了至少30分钟。当2-氨基乙氧基二苯berate (2APB)（一种吲哚类1,4,5-三磷酸受体（IP3R）和SOC的抑制剂）与ATP联合使用时，它能够完全抑制CCE。由于2APB可以抑制某些细胞类型的SOC，并且在UAEC模型中2APB能够抑制CCE，因此首先使用经典抑制剂La来评估SOC在CCE中的作用。10 μ M La3+抑制了atp诱导的持续期，表明SOC在[Ca2+](i)反应中起作用。由于典型瞬时受体电位通道（trpc）最近在包括EC在内的许多细胞类型中被确定为假定的soc，因此在UAEC中评估了几种亚型的表达水平。特别是检测到TPPC3和TRPC6通道的表达，但NP-和P-UAEC之间的表达水平无显著差异。尽管如此，我们能够证明IP3R2与UAEC中的TRPC3相互作用，形成一种蛋白质复合物，并且这种相互作用在妊娠期间以激动剂敏感的方式显著增强。因此，虽然IP3R和TRPC亚型的表达不会因怀孕而改变，但在UAEC模型中，TRPC3与IP3R2的功能相互作用增强可能是妊娠增强CCE的基础，从而解释了ATP反应中延长的[Ca2+](i)持续期。
We have previously shown that endothelial cells (EC) derived from the uterine artery (UA) of both pregnant (P-UAEC) and nonpregnant (NP-UAEC) ewes show a biphasic intracellular free Ca2+ ([Ca2+](i)) response after ATP stimulation. In each case, the initial transient peak, caused by the release of Ca2+ from the intracellular Ca2+ stores, is mediated by purinergic receptor-Y2 and is very similar in both cell types. However, the sustained phase in particular, caused by the influx of extracellular Ca2+, is heightened in the P-UAEC, and associates with an increased ability of the cells to demonstrate enhanced capacitative Ca2+ entry (CCE) via store-operated channels (SOCs). Herein we demonstrated that the difference in the sustained [Ca2+](i) response is maintained for at least 30 min. When 2-aminoethoxydiphenyl berate (2APB) (an inhibitor of the inosital 1,4,5-trisphosphate receptor (IP3R) and possibly SOC) was used in con unction with ATP it was capable of completely inhibiting CCE. Since 2APB can inhibit SOC in some cell types and 2APB was capable of inhibiting CCE in the UAEC model, the role of SOC in CCE was first evaluated using the classical inhibitor La. The ATP-induced sustained phase was inhibited by 10 mu M La3+, implying a role for SOC in the [Ca2+](i) response. Since canonical transient receptor potential channels (TRPCs) have recently been identified as putative SOCs in many cell types, including EC, the expression levels of several isoforms were evaluated in UAEC. Expression of TPPC3 and TRPC6 channels in particular was detected, but no significant difference in expression level was found between NP- and P-UAEC. Nonetheless, we were able to show that IP3R2 interacts with TRPC3 in UAEC, forming a protein complex, and that this interaction is considerably enhanced in an agonist sensitive manner by pregnancy. Thus, while IP3R and TRPC isoforms are not altered in their expression by pregnancy, enhanced functional interaction of TRPC3 with IP3R2 may underlie pregnancy-enhanced CCE in the UAEC model and so explain the prolonged [Ca2+](i) sustained phase seen in response to ATP.