TREK-1 currents in smooth muscle cells from pregnant human myometrium
TREK-1 currents in smooth muscle cells from pregnant human myometrium
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DOI：
10.1152/ajpcell.00324.2012
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发表时间：
2013-09-01
影响因子：
5.5
通讯作者：
Buxton, Iain L. O.
中科院分区：
文献类型：
--
作者：
Heyman, Nathanael S.;Cowles, Chad L.;Buxton, Iain L. O.
孕期维持静止状态的机制在很大程度上仍然未知。当前的研究对从妊娠期人子宫肌层分离出的平滑肌细胞中的一种牵张激活的、对四乙铵不敏感的钾离子电流进行了特征描述。本研究假设这些钾离子电流可归因于TREK - 1，并且在孕期该通道的上调有助于维持细胞膜的负电位，可能有助于子宫在足月前保持静止状态。这项研究的结果表明，在妊娠期人子宫肌层细胞中，施加花生四烯酸（AA）和碳酸氢钠（NaHCO₃）分别使80 mV时的外向电流从4.8 ± 1.5增加到19.4 ± 7.5 pA/pF以及从3.0 ± 0.8增加到11.8 ± 2.7 pA/pF，这两种物质都会引起细胞内酸化。同样，在施加10 μM氟奋乃静后，经AA激活后的外向电流被抑制了51.2 ± 9.8%，经NaHCO₃激活后的外向电流被抑制了73.9 ± 4.2%。在稳定表达TREK - 1的人胚胎肾（HEK - 293）细胞中，施加AA和NaHCO₃分别使80 mV时的外向电流从91.0 ± 23.8增加到247.5 ± 73.3 pA/pF以及从34.8 ± 8.9增加到218.6 ± 45.0 pA/pF。相应地，在施加AA激活后，10 μM氟奋乃静抑制外向电流89.5 ± 2.3%，在施加NaHCO₃激活后抑制91.6 ± 3.4%。此外，人子宫肌层细胞中的电流可被牵张激活，并可通过小干扰RNA转染或细胞外酸化而降低。了解TREK - 1通道在孕期的表达和门控的妊娠调节对于确定孕期子宫静止状态的适当维持可能很重要。
The mechanisms governing maintenance of quiescence during pregnancy remain largely unknown. The current study characterizes a stretch-activated, tetraethylammonium-insensitive K+ current in smooth muscle cells isolated from pregnant human myometrium. This study hypothesizes that these K+ currents can be attributed to TREK-1 and that upregulation of this channel during pregnancy assists with the maintenance of a negative cell membrane potential, conceivably contributing to uterine quiescence until full term. The results of this study demonstrate that, in pregnant human myometrial cells, outward currents at 80 mV increased from 4.8 +/- 1.5 to 19.4 +/- 7.5 pA/pF and from 3.0 +/- 0.8 to 11.8 +/- 2.7 pA/pF with application of arachidonic acid (AA) and NaHCO3, respectively, causing intracellular acidification. Similarly, outward currents were inhibited following application of 10 mu M fluphenazine by 51.2 +/- 9.8% after activation by AA and by 73.9 +/- 4.2% after activation by NaHCO3. In human embryonic kidney (HEK-293) cells stably expressing TREK-1, outward currents at 80 mV increased from 91.0 +/- 23.8 to 247.5 +/- 73.3 pA/pF and from 34.8 +/- 8.9 to 218.6 +/- 45.0 pA/pF with application of AA and NaHCO3, respectively. Correspondingly, outward currents were inhibited 89.5 +/- 2.3% by 10 mu M fluphenazine following activation by AA and by 91.6 +/- 3.4% following activation by NaHCO3. Moreover, currents in human myometrial cells were activated by stretch and were reduced by transfection with small interfering RNA or extracellular acidification. Understanding gestational regulation of expression and gating of TREK-1 channels could be important in determining appropriate maintenance of uterine quiescence during pregnancy.