Functional Characterization of Transient Receptor Potential (TRP) Channel C5 in Female Murine Gonadotropes
Functional Characterization of Transient Receptor Potential (TRP) Channel C5 in Female Murine Gonadotropes
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DOI：
10.1210/en.2016-1810
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发表时间：
2017-04-01
期刊：
影响因子：
4.8
通讯作者：
Boehm, Ulrich
中科院分区：
文献类型：
--
作者：
Beck, Andreas;Goetz, Viktoria;Boehm, Ulrich
垂体前叶的促性腺激素细胞分泌调节哺乳动物性腺功能的促性腺激素。最近的研究结果表明，瞬时受体电位（TRP）阳离子通道与垂体生理学有关。然而，TRP 通道是否以及如何促进促性腺激素功能尚不清楚。在此，我们报告小鼠基因组中编码的 28 个 TRP 通道中有 14 个在小鼠促性腺激素中表达，其中在幼年雌性中发现的典型 TRP (TRPC) 通道 5 表达水平最高。我们发现这些细胞中的 TRP 通道表达表现出相当大的可塑性，并且它取决于动物的性别以及发育和激素状态。然后，我们结合不同的遗传策略，包括在整体垂体制剂中进行遗传共焦 Ca2+ 成像，以表征幼年雌性促性腺激素中 TRPC5 通道的功能。我们发现 TRPC5 激动剂 Englerin A 可激活这些细胞中的胞质 Ca2+ 信号和全细胞电流，而这在 TRPC5 缺陷小鼠中是不存在的，并证明 TRPC5 与促性腺激素中的 TRPC1 形成功能性异多聚体。我们进一步表明，Englerin A 激活的 TRPC5 依赖性 Ca2+ 信号是通过 TRPC5 和 L 型电压门控 Ca2+ 通道的 Ca2+ 内流介导的，并由 TRPC5 介导的阳离子内流的去极化激活。最后，我们证明，从 TRPC5 缺陷小鼠中分离出的促性腺激素中，促性腺激素释放激素 (GnRH) 介导的净去极化显着降低。总之，我们的数据表明，TRPC5 在 GnRH 刺激下有助于促性腺激素中质膜的去极化，并通过其自身的 Ca2+ 渗透性和电压门控 Ca2+ 通道的激活增加细胞内 Ca2+ 浓度。
Gonadotrope cells in the anterior pituitary gland secrete gonadotropins regulating gonadal function in mammals. Recent results have implicated transient receptor potential (TRP) cation channels in pituitary physiology; however, if and how TRP channels contribute to gonadotrope function is not known. Here, we report that 14 out of 28 TRP channels encoded in the mouse genome are expressed in murine gonadotropes with highest expression levels found for canonical TRP (TRPC) channel 5 in juvenile females. Weshow that TRP channel expression in these cells exhibits considerable plasticity and that it depends on the sex and the developmental and hormonal status of the animal. We then combine different genetic strategies including genetic confocal Ca2+ imaging in whole-mount pituitary gland preparations to characterize TRPC5 channel function in gonadotropes from juvenile females. We show that the TRPC5 agonist Englerin A activates a cytosolic Ca2+ signal and a whole-cell current in these cells, which is absent in TRPC5-deficient mice, and demonstrate that TRPC5 forms functional heteromultimers with TRPC1 in gonadotropes. We further show that the Englerin A-activated TRPC5-dependent Ca2+ signal is mediated by Ca2+ influx both via TRPC5 and via L-type voltage-gated Ca2+ channels, activated by the depolarization through TRPC5-mediated cation influx. Finally, we demonstrate that the gonadotropin-releasing hormone (GnRH)-mediated net depolarization is significantly reduced in gonadotropes isolated from TRPC5-deficient mice. In conclusion, our data suggest that TRPC5 contributes to depolarization of the plasma membrane in gonadotropes upon GnRH stimulation and increases the intracellular Ca2+ concentration via its own Ca2+ permeability and via the activation of voltage-gated Ca2+ channels.