孤束核中 GRK6 的下调通过新生儿期母体剥夺成年大鼠 NF-κB 的上调促进慢性内脏敏感性。
Downregulation of GRK6 in arcuate nucleus promotes chronic visceral hypersensitivity via NF-κB upregulation in adult rats with neonatal maternal deprivation.
机构信息
Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, P. R. China.
Center for Translational Pain Medicine, Institute of Neuroscience, Soochow University, Suzhou, P. R. China.
出版信息
Mol Pain. 2020 Jan-Dec;16:1744806920930858. doi: 10.1177/1744806920930858.
AIMS
The arcuate nucleus is a vital brain region for coursing of pain command. G protein-coupled kinase 6 (GRK6) accommodates signaling through G protein-coupled receptors. Studies have demonstrated that GRK6 is involved in inflammatory pain and neuropathic pain. The present study was designed to explore the role and the underlying mechanism of GRK6 in arcuate nucleus of chronic visceral pain.
METHODS
Chronic visceral pain of rats was induced by neonatal maternal deprivation and evaluated by monitoring the threshold of colorectal distension. Western blotting, immunofluorescence, real-time quantitative polymerase chain reaction techniques, and Nissl staining were employed to determine the expression and mutual effect of GRK6 with nuclear factor κB (NF-κB).
RESULTS
Expression of GRK6 in arcuate nucleus was significantly reduced in neonatal maternal deprivation rats when compared with control rats. GRK6 was mainly expressed in arcuate nucleus neurons, but not in astrocytes, and a little in microglial cells. Neonatal maternal deprivation reduced the percentage of GRK6-positive neurons of arcuate nucleus. Overexpression of GRK6 by Lentiviral injection into arcuate nucleus reversed chronic visceral pain in neonatal maternal deprivation rats. Furthermore, the expression of NF-κB in arcuate nucleus was markedly upregulated in neonatal maternal deprivation rats. NF-κB selective inhibitor pyrrolidine dithiocarbamate suppressed chronic visceral pain in neonatal maternal deprivation rats. GRK6 and NF-κB were expressed in the arcuate nucleus neurons. Importantly, overexpression of GRK6 reversed NF-κB expression at the protein level. In contrast, injection of pyrrolidine dithiocarbamate once daily for seven consecutive days did not alter GRK6 expression in arcuate nucleus of neonatal maternal deprivation rats.
CONCLUSIONS
Present data suggest that GRK6 might be a pivotal molecule participated in the central mechanisms of chronic visceral pain, which might be mediated by inhibiting NF-κB signal pathway. Overexpression of GRK6 possibly represents a potential strategy for therapy of chronic visceral pain.
目的
弓状核是疼痛指令传导的重要脑区。G 蛋白偶联激酶 6（GRK6）适应 G 蛋白偶联受体的信号传递。研究表明，GRK6 参与了炎症性疼痛和神经性疼痛。本研究旨在探讨 GRK6 在慢性内脏痛弓状核中的作用及其潜在机制。
方法
通过新生期母鼠剥夺诱导大鼠慢性内脏痛，并通过监测结肠扩张阈值来评估。采用 Western blot、免疫荧光、实时定量聚合酶链反应技术和尼氏染色来确定 GRK6 与核因子 κB（NF-κB）的表达及其相互作用。
结果
与对照组大鼠相比，新生期母鼠剥夺大鼠弓状核中 GRK6 的表达明显降低。GRK6 主要在弓状核神经元中表达，但不在星形胶质细胞中表达，在小胶质细胞中也有少量表达。新生期母鼠剥夺减少了弓状核 GRK6 阳性神经元的比例。通过 Lentiviral 注射将 GRK6 过表达到弓状核中，逆转了新生期母鼠剥夺大鼠的慢性内脏痛。此外，新生期母鼠剥夺大鼠弓状核中 NF-κB 的表达明显上调。NF-κB 选择性抑制剂吡咯烷二硫代氨基甲酸盐（PDTC）抑制了新生期母鼠剥夺大鼠的慢性内脏痛。GRK6 和 NF-κB 在弓状核神经元中表达。重要的是，过表达 GRK6 逆转了 NF-κB 蛋白水平的表达。相反，连续 7 天每天注射一次 PDTC 不会改变新生期母鼠剥夺大鼠弓状核中的 GRK6 表达。
结论
目前的数据表明，GRK6 可能是参与慢性内脏痛中枢机制的关键分子，可能通过抑制 NF-κB 信号通路来介导。过表达 GRK6 可能代表治疗慢性内脏痛的一种潜在策略。
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