Androgen receptor transcriptionally regulates μ-opioid receptor expression in rat trigeminal ganglia.
Androgen receptor transcriptionally regulates μ-opioid receptor expression in rat trigeminal ganglia.
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DOI：
10.1016/j.neuroscience.2016.06.023
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发表时间：
2016-09-07
期刊：
影响因子：
3.3
通讯作者：
Ro JY
中科院分区：
文献类型：
--
作者：
Lee KS;Zhang Y;Asgar J;Auh QS;Chung MK;Ro JY
睾酮参与疼痛、炎症和镇痛已有报道，但雄激素受体（AR）（睾酮的类固醇受体）的作用尚不清楚。我们先前已经证明外周炎症以睾酮依赖的方式上调大鼠三叉神经节（TG）中的μ-阿片受体（莫尔）。在这项研究中，我们假设睾酮调节莫尔的表达，通过转录活动的AR在TG。我们首先研究了在TG神经元中AR是否与莫尔共表达。我们的免疫组化实验表明，AR染色检测在TG中的所有大小的神经元和AR的一个子集在莫尔以及TRPV 1阳性神经元中表达。我们鉴定了大鼠莫尔基因的启动子区含有推定的AR结合位点。使用染色质免疫沉淀分析，我们证明了AR直接结合到TG提取物中的这些位点。我们用荧光素酶报告基因检测证实，在人神经母细胞瘤细胞系（5 H-5 YSY）中，AR激活了雄激素应答的莫尔启动子。这些数据表明，AR作为莫尔基因活性的转录调节因子发挥作用。最后，我们发现，特异性AR拮抗剂氟替卡松可阻止完全弗氏佐剂（CFA）诱导的TG中莫尔mRNA的上调，并且氟替卡松剂量依赖性地阻断特异性莫尔激动剂DAMGO对CFA诱导的机械超敏反应的功效。我们的研究结果扩大了关于雄激素及其受体在疼痛和镇痛中的作用的知识，并具有重要的临床意义，特别是对于血浆睾酮水平低或受损的炎性疼痛患者。
The involvement of testosterone in pain, inflammation, and analgesia has been reported, but the role of androgen receptor (AR), a steroid receptor for testosterone, is not well understood. We have previously shown that peripheral inflammation upregulates μ-opioid receptor (MOR) in rat trigeminal ganglia (TG) in a testosterone-dependent manner. In this study, we hypothesized that testosterone regulates MOR expression via transcriptional activities of AR in TG. We first examined whether AR is co-expressed with MOR in TG neurons. Our immunohistochemical experiment revealed that AR staining is detected in neurons of all sizes in TG and that a subset of AR is expressed in MOR as well as in TRPV1-positive neurons. We identified the promoter region of the rat MOR gene contains putative AR binding sites. Using chromatin immunoprecipitation assay, we demonstrated that AR directly binds to these sites in TG extracts. We confirmed with luciferase reporter assay that AR activated the MOR promoter in response to androgens in a human neuroblastoma cell line (5H-5YSY). These data demonstrated that AR functions as a transcriptional regulator of the MOR gene activity. Finally, we showed that flutamide, a specific AR antagonist, prevents complete Freund’s adjuvant (CFA)-induced upregulation of MOR mRNA in TG, and that flutamide dose-dependently blocks the efficacy of DAMGO, a specific MOR agonist, on CFA-induced mechanical hypersensitivity. Our results expand the knowledge regarding the role of androgens and their receptor in pain and analgesia and have important clinical implications, particularly for inflammatory pain patients with low or compromised plasma testosterone levels.