Sex-dependent pronociceptive role of spinal α5-GABAA receptor and its epigenetic regulation in neuropathic rodents
Sex-dependent pronociceptive role of spinal α5-GABAA receptor and its epigenetic regulation in neuropathic rodents
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DOI：
10.1111/jnc.15140
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发表时间：
2020-08-26
影响因子：
4.7
通讯作者：
Granados-Soto, Vinicio
中科院分区：
文献类型：
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作者：
Franco-Enzastiga, Urzula;Garcia, Guadalupe;Granados-Soto, Vinicio
含有GABA（A）（α（5）-GABA（A））受体的突触外α（5）-亚基参与慢性疼痛。以前，我们报道了在功能失调性疼痛中α（5）-GABA（A）受体的作用存在性别差异。然而，其潜在机制仍不清楚。本研究的目的是研究神经病啮齿动物的性二态性及其机制。对雌性和雄性Wistar大鼠或ICR小鼠进行神经损伤，然后鞘内给予α（5）-GABA（A）受体反向激动剂L-655，708。该药物在神经损伤的雌性大鼠和小鼠中产生抗异常性疼痛作用，在雄性中的作用较低。我们假设α（5）-GABA（A）受体的变化可能受到激素和表观遗传状态的影响，可能是这种性别差异的基础。因此，我们进行了qPCR和蛋白质印迹。神经损伤后，雌性大鼠背根神经节（DRG）α（5）-GABA（A）mRNA和蛋白表达增加，雄性大鼠DRG和脊髓α（5）-GABA（A）mRNA和蛋白表达减少。为了研究激素对α（5）-GABA（A）受体作用的影响，我们对卵巢切除大鼠进行神经损伤，并用17 β-雌二醇（E2）重建它们。去卵巢可使L-655，708的抗异常性疼痛作用消失，E2可使其恢复，去卵巢可使神经病雌性大鼠背根神经节α（5）-GABA（A）受体和雌激素受体α蛋白表达减少，E2可使其增强。由于DNA甲基化可能与男性α（5）-GABA（A）受体表达下调有关，我们通过焦磷酸测序检测了α（5）-GABA（A）受体编码基因的CpG岛DNA甲基化。神经损伤增加雄性大鼠的甲基化，但不增加雌性大鼠的甲基化。药理学抑制DNA甲基转移酶增加α（5）-GABA（A）受体，并使L-655，708在雄性大鼠中具有抗伤害感受作用。这些结果表明，α（5）-GABA（A）受体是治疗女性慢性疼痛的合适靶点。
Extrasynaptic alpha(5)-subunit containing GABA(A)(alpha(5)-GABA(A)) receptors participate in chronic pain. Previously, we reported a sex difference in the action of alpha(5)-GABA(A)receptors in dysfunctional pain. However, the underlying mechanisms remain unknown. The aim of this study was to examine this sexual dimorphism in neuropathic rodents and the mechanisms involved. Female and male Wistar rats or ICR mice were subjected to nerve injury followed by alpha(5)-GABA(A)receptor inverse agonist intrathecal administration, L-655,708. The drug produced an antiallodynic effect in nerve-injured female rats and mice, and a lower effect in males. We hypothesized that changes in alpha(5)-GABA(A)receptor, probably influenced by hormonal and epigenetic status, might underlie this sex difference. Thus, we performed qPCR and western blot. Nerve injury increased alpha(5)-GABA(A)mRNA and protein in female dorsal root ganglia (DRG) and decreased them in DRG and spinal cord of males. To investigate the hormonal influence over alpha(5)-GABA(A)receptor actions, we performed nerve injury to ovariectomized rats and reconstituted them with 17 beta-estradiol (E2). Ovariectomy abrogated L-655,708 antiallodynic effect and E2 restored it. Ovariectomy decreased alpha(5)-GABA(A)receptor and estrogen receptor alpha protein in DRG of neuropathic female rats, while E2 enhanced them. Since DNA methylation might contribute to alpha(5)-GABA(A)receptor down-regulation in males, we examined CpG island DNA methylation of alpha(5)-GABA(A)receptor coding gene through pyrosequencing. Nerve injury increased methylation in male, but not female rats. Pharmacological inhibition of DNA methyltransferases increased alpha(5)-GABA(A)receptor and enabled L-655,708 antinociceptive effect in male rats. These results suggest that alpha(5)-GABA(A)receptor is a suitable target to treat chronic pain in females.