Thromboxane A2-induced inhibition of voltage-gated K+ channels and pulmonary vasoconstriction -: Role of protein kinase Cζ
Thromboxane A2-induced inhibition of voltage-gated K+ channels and pulmonary vasoconstriction -: Role of protein kinase Cζ
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DOI：
10.1161/01.res.0000095245.97945.fe
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发表时间：
2003-10-03
影响因子：
20.1
通讯作者：
Perez-Vizcaino, F
中科院分区：
文献类型：
--
作者：
Cogolludo, A;Moreno, L;Perez-Vizcaino, F
电压门控 K+ 通道 (K-V) 和血栓素 A(2) (TXA(2)) 在生理和病理条件下控制肺动脉张力方面发挥着关键作用。我们假设 TXA2 可能抑制 KV 通道，从而在肺动脉高压的这两个主要致病途径之间建立联系。 TXA2 类似物 U46619 通过激活 TP 受体抑制 I-K(V)（E-max = 56.1 +/- 3.9%，EC50 = 0.054 +/- 0.019 mumol/L）并去极化肺动脉平滑肌细胞。在离体肺动脉中，U46619同时增加细胞内Ca2+浓度和收缩力，并且这些作用被硝苯地平或KCl（60 mmol/L）抑制。 U46619 诱导的收缩不会被酪氨酸激酶金雀异黄素或 Rho 激酶 Y-27632 抑制剂改变，但会被非选择性蛋白激酶 C (PKC) 抑制剂十字孢菌素和钙磷蛋白 C 阻止。此外，这些反应对 Go-6983 敏感，但对双吲哚马来酰亚胺 I 和 Go-6976 不敏感。基于这些药物的特异性，我们提出非典型 PKC 在 U46619 诱导的作用中的作用。因此，用 PKCzeta 假底物抑制剂治疗可显着阻止 U46619 诱导的血管收缩、I-K(V) 抑制和去极化。蛋白质印迹显示，在 U46619 刺激下，PKCzeta 从胞质部分瞬时易位至颗粒部分。这些结果表明，TXA2 抑制 IK(V)，导致去极化、L 型 Ca2+ 通道激活以及大鼠肺动脉血管收缩。我们建议 PKCzeta 作为 TP 受体激活和 K-V 通道抑制之间的联系。
Voltage-gated K+ channels (K-V) and thromboxane A(2) (TXA(2)) play critical roles in controlling pulmonary arterial tone under physiological and pathological conditions. We hypothesized that TXA2 might inhibit KV channels, thereby establishing a link between these two major pathogenic pathways in pulmonary hypertension. The TXA2 analogue U46619 inhibited I-K(V) (E-max = 56.1 +/- 3.9%, EC50 = 0.054 +/- 0.019 mumol/L) and depolarized pulmonary artery smooth muscle cells via activation of TP receptors. In isolated pulmonary arteries, U46619 simultaneously increased intracellular Ca2+ concentration and contractile force, and these effects were inhibited by nifedipine or KCl ( 60 mmol/L). U46619-induced contractions were not altered by the inhibitors of tyrosine kinase genistein or Rho kinase Y-27632 but were prevented by the nonselective protein kinase C (PKC) inhibitors staurosporine and calphostin C. Furthermore, these responses were sensitive to Go-6983 but insensitive to bisindolylmaleimide I and Go-6976. Based on the specificity of these drugs, we suggested a role for an atypical PKC in U46619-induced effects. Thus, treatment with a PKCzeta pseudosubstrate inhibitor markedly prevented the vasoconstriction, the inhibition of I-K(V), and the depolarization induced by U46619. Western blots showed a transient translocation of PKCzeta from the cytosolic to the particulate fraction on stimulation with U46619. These results indicate that TXA2 inhibits IK( V), leading to depolarization, activation of L-type Ca2+ channels, and vasoconstriction of rat pulmonary arteries. We propose PKCzeta as a link between TP receptor activation and K-V channel inhibition.