Alpha1G T-type calcium channel selectively regulates P-selectin surface expression in pulmonary capillary endothelium.
Alpha1G T-type calcium channel selectively regulates P-selectin surface expression in pulmonary capillary endothelium.
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DOI：
10.1152/ajplung.00331.2009
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发表时间：
2010-07
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影响因子：
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通讯作者：
Chun Zhou;Hairu Chen;J. King;H. Sellak;W. Kuebler;Jun-fei Yin;M. Townsley;Hee-Sup Shin;Songwei Wu
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文献类型：
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作者：
Chun Zhou;Hairu Chen;J. King;H. Sellak;W. Kuebler;Jun-fei Yin;M. Townsley;Hee-Sup Shin;Songwei Wu
p -选择素表面表达的调节为内皮细胞向促炎表型的转变提供了快速的测量方法。一般情况下，p -选择素的表面表达源于韦贝尔-帕拉德体（webel - palade body, WPb）胞吐。然而，尚不清楚肺毛细血管内皮是否具有WPbs或调节p -选择素表面表达，如果有，炎症刺激如何引发胞吐。我们使用免疫组织化学、免疫荧光标记、超微结构评估和离体灌注肺模型来证明毛细血管内皮缺乏WPbs，但具有p -选择素。凝血酶刺激p -选择素在肺泡外血管和肺泡毛细血管内皮的表达。只有在毛细血管中，凝血素刺激的p -选择素表面表达通过药物阻断t型通道或基因敲除t型通道α (1G)-亚基而显著减轻。通过高K（+）灌注内皮质膜去极化，能够引发胞浆内Ca（2+）瞬态，也会引起肺泡毛细血管中p -选择素表面的表达，这种表达被t型通道阻断或α (1G)敲除所消除。我们的研究结果揭示了肺毛细血管内皮细胞内存在一个不依赖于wpb的p -选择素池，其中受调节的p -选择素表面表达是由α (1G) t型通道激活引起的Ca（2+）瞬态触发的。
Regulated P-selectin surface expression provides a rapid measure for endothelial transition to a proinflammatory phenotype. In general, P-selectin surface expression results from Weibel-Palade body (WPb) exocytosis. Yet, it is unclear whether pulmonary capillary endothelium possesses WPbs or regulated P-selectin surface expression and, if so, how inflammatory stimuli initiate exocytosis. We used immunohistochemistry, immunofluorescence labeling, ultrastructural assessment, and an isolated perfused lung model to demonstrate that capillary endothelium lacks WPbs but possesses P-selectin. Thrombin stimulated P-selectin surface expression in both extra-alveolar vessel and alveolar capillary endothelium. Only in capillaries was the thrombin-stimulated P-selectin surface expression considerably mitigated by pharmacologic blockade of the T-type channel or genetic knockout of the T-type channel alpha(1G)-subunit. Depolarization of endothelial plasma membrane via high K(+) perfusion capable of eliciting cytosolic Ca(2+) transients also provoked P-selectin surface expression in alveolar capillaries that was abolished by T-type channel blockade or alpha(1G) knockout. Our findings reveal an intracellular WPb-independent P-selectin pool in pulmonary capillary endothelium, where the regulated P-selectin surface expression is triggered by Ca(2+) transients evoked through activation of the alpha(1G) T-type channel.