PDF(Pubmed)
Abstract：
Nerve injury-induced alternations of gene expression in primary sensory neurons of the dorsal root ganglion (DRG) are molecular basis of neuropathic pain genesis. Transcription factors regulate gene expression. In this study, we examined whether early B cell factor 1 (EBF1), a transcription factor, in the DRG, participated in neuropathic pain caused by chronic constriction injury (CCI) of the sciatic nerve. EBF1 was distributed exclusively in the neuronal nucleus and coexpressed with cytoplasmic/membrane Kv1.2 in individual DRG neurons. The expression of Ebf1 mRNA and protein was time-dependently downregulated in the ipsilateral lumbar (L) 3/4 DRGs after unilateral CCI. Rescuing this downregulation through microinjection of the adeno-associated virus 5 expressing full-length Ebf1 mRNA into the ipsilateral L3/4 DRGs reversed the CCI-induced decrease of DRG Kv1.2 expression and alleviated the development and maintenance of mechanical, heat and cold hypersensitivities. Conversely, mimicking the downregulation of DRG EBF1 through microinjection of AAV5-expressing Ebf1 shRNA into unilateral L3/4 DRGs produced a reduction of Kv1.2 expression in the ipsilateral L3/4 DRGs, spontaneous pain, and the enhanced responses to mechanical, heat and cold stimuli in naive mice. Mechanistically, EBF1 not only bound to the Kcna2 gene (encoding Kv1.2) promoter but also directly activated its activity. CCI decreased the EBF1 binding to the Kcna2 promoter in the ipsilateral L3/4 DRGs. Our findings suggest that DRG EBF1 downregulation contributes to neuropathic pain likely by losing its binding to Kcna2 promoter and subsequently silencing Kv1.2 expression in primary sensory neurons. Exogenous EBF1 administration may mitigate neuropathic pain by rescuing DRG Kv1.2 expression.
摘要：
神经损伤引起的背根神经节（DRG）初级感觉神经元基因表达的变化是神经性疼痛发生的分子基础。转录因子调节基因表达。在这项研究中,我们检查了早期B细胞因子1（EBF1），转录因子，DRG参与了坐骨神经慢性压迫性损伤（CCI）引起的神经性疼痛。EBF1仅分布在神经元核中，并在单个DRG神经元中与细胞质/膜Kv1.2共表达。单侧CCI后，同侧腰椎（L）3/4DRGs中Ebf1mRNA和蛋白的表达呈时间依赖性下调。通过将表达全长Ebf1mRNA的腺相关病毒5显微注射到同侧L3/4DRG中来挽救这种下调，逆转了CCI诱导的DRGKv1.2表达的降低，并减轻了机械的发展和维持，热和冷的超敏反应。相反，通过将表达AAV5的Ebf1shRNA显微注射到单侧L3/4DRGs中模拟DRGEBF1的下调，导致同侧L3/4DRGs中Kv1.2表达减少，自发性疼痛和对机械的增强反应，幼稚小鼠的热和冷刺激。机械上,EBF1不仅与Kcna2基因（编码Kv1.2）启动子结合，而且直接激活其活性。CCI降低了同侧L3/4DRGs中EBF1与Kcna2启动子的结合。我们的发现表明，DRGEBF1下调可能通过失去与Kcna2启动子的结合并随后在初级感觉神经元中沉默Kv1.2表达而导致神经性疼痛。外源性EBF1施用可通过挽救DRGKv1.2表达来减轻神经性疼痛。
