Participation of Gαi-Adenylate Cyclase and ERK1/2 in Mas Receptor Signaling Pathways
Participation of Gαi-Adenylate Cyclase and ERK1/2 in Mas Receptor Signaling Pathways
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DOI：
10.3389/fphar.2019.00146
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发表时间：
2019-02-22
影响因子：
5.6
通讯作者：
Dominici, Fernando P.
中科院分区：
文献类型：
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作者：
Burghi, Valeria;Echeverria, Emiliana B.;Dominici, Fernando P.
MASR受体(MASR)是一种孤立的G蛋白偶联受体，被认为是介导肾素-血管紧张素系统血管紧张素转换酶2-Ang-(1-7)保护轴的候选受体。这种受体被认为参与了几个生理过程，包括心脏和肾脏的保护以及中枢神经系统功能的调节。尽管对与MASR相关的信号机制的了解对于治疗目的是必不可少的，但这些知识仍然知之甚少。因此，在目前的研究中，我们的目标是表征由MASR触发的信号通路。为了做到这一点，我们测量了在基础条件下和与假定的MASR配体孵育时，NAIVE和MASR转基因细胞中的cAMP和钙水平。此外，我们还检测了Ang-(1-7)对MASR转基因细胞ERK1/2的激活作用。结果表明，MASR对cAMP的调节具有高度的结构性活性。这种作用不是通过MASR的PDZ结合基序介导的，而是通过受体偶联GαI-腺苷环化酶信号通路来实现的。用Ang-(1-7)或合成配体AVE 0991孵育MASR基因的细胞，可使MASR负性调节cAMP水平。另一方面，我们提供了Ang-(1-7)缺乏MASR相关的钙水平调节作用的证据。最后确定MASR减弱了AT1R介导的Ang-(1-7)诱导的ERK1/2的磷酸化。我们提供了关于其构成活性和对假定配体的响应的MASR信号机制的进一步表征。这些信息可能被证明有助于更好地描述MASR的生理作用和可以调节其作用的治疗剂的发展。
The MasR receptor (MasR) is an orphan G protein-coupled receptor proposed as a candidate for mediating the angiotensin (Ang)-converting enzyme 2-Ang-(1-7) protective axis of renin-angiotensin system. This receptor has been suggested to participate in several physiological processes including cardio-and reno-protection and regulation of the central nervous system function. Although the knowledge of the signaling mechanisms associated with MasR is essential for therapeutic purposes, these are still poorly understood. Accordingly, in the current study we aimed to characterize the signaling pathways triggered by the MasR. To do that, we measured cAMP and Ca2+ levels in both naive and MasR transfected cells in basal conditions and upon incubation with putative MasR ligands. Besides, we evaluated activation of ERK1/2 by Ang-(1-7) in MasR transfected cells. Results indicated the existence of a high degree of MasR constitutive activity toward cAMP modulation. This effect was not mediated by the PDZ-binding motif of the MasR but by receptor coupling to G alpha i-adenylyl cyclase signaling pathway. Incubation of MasR transfected cells with Ang-(1-7) or the synthetic ligand AVE 0991 amplified MasR negative modulation of cAMP levels. On the other hand, we provided evidence for lack of MasR-associated modulation of Ca2+ levels by Ang-(1-7). Finally, it was determined that the MasR attenuated Ang-(1-7)-induced ERK1/2 phosphorylation mediated by AT1R. We provided further characterization of MasR signaling mechanisms regarding its constitutive activity and response to putative ligands. This information could prove useful to better describe MasR physiological role and development of therapeutic agents that could modulate its action.