Epigenetic regulation of neuropathic pain: Role of native KV1.2 antisense RNA

描述（由申请人提供）：揭示神经性疼痛中疼痛超敏反应的分子机制可能有助于开发治疗这种疾病的新治疗策略。已在哺乳动物细胞中鉴定的非编码RNA调节基因表达。它们的表达与神经系统疾病的发展有关，但非编码RNA与疾病的因果关系尚不清楚。我们最近在背根神经节（DRG）中发现了一个与电压门控K+通道（Kv）1.2 mRNA互补的大的、天然的、全长非编码RNA（2，574 nt）。我们的数据表明，这种Kv1.2反义（AS）RNA可能通过激活MZF-1转录因子在周围神经损伤后受损的DRG中上调。阻断这种上调可能会减弱神经性疼痛的诱导。这些初步研究结果表明，DRG Kv1.2 AS RNA参与神经病理性疼痛的分子机制。该提案将进一步表征DRG中的天然Kv1.2 AS RNA，并确定该AS RNA是否以及如何促成神经性疼痛。在具体目标1中，我们将检查Kv1.2 AS RNA在DRG中的表达和分布，并确定正常大鼠含Kv1.2 AS RNA的DRG神经元的细胞化学特征。在具体目标2中，我们将研究周围神经损伤是否会增加DRG中Kv1.2 AS RNA及其转录因子MZF-1的表达。此外，我们还将检测外周神经损伤后，受损DRG中Kv1.2 AS基因启动子上的共有序列与MZF-1结合是否导致Kv1.2 AS RNA上调。在具体目标3中，我们将使用病毒介导的基因转移策略，以确定是否Kv1.2 AS RNA的过表达特异性和选择性地降低DRG神经元中Kv1.2 mRNA和蛋白的表达以及总Kv电流密度，增加DRG神经元兴奋性，并导致大鼠神经病理性疼痛的主要症状。我们还将研究阻断大鼠神经损伤诱导的Kv1.2 AS RNA上调是否逆转神经损伤诱导的DRG Kv1.2表达和总Kv电流密度降低，并减弱神经损伤诱导的DRG神经元异常自发活动和疼痛超敏反应。这些研究将为我们理解神经病理性疼痛的分子机制提供重要的概念性进展，并可能为开发治疗神经病理性疼痛的新策略打开大门。

DESCRIPTION (provided by applicant): Uncovering molecular mechanisms that underlie pain hypersensitivity in neuropathic pain may allow development of novel therapeutic strategies for treating this disorder. Non-coding RNAs that have been identified in mammalian cells regulate gene expression. Their expression is associated with the development of neurological diseases, but how non-coding RNA is causally linked to the diseases is unknown. We recently indentified a large, native, full-length non-coding RNA (2,574 nt) that is complementary to voltage-gated K+ channel (Kv) 1.2 mRNA in the dorsal root ganglion (DRG). Our data indicate that this Kv1.2 antisense (AS) RNA might be up-regulated via the activation of MZF-1 transcription factor in the injured DRG after peripheral nerve injury. Blocking this up-regulation might attenuate the induction of neuropathic pain. These preliminary findings suggest that DRG Kv1.2 AS RNA participates in the molecular mechanisms that underlie neuropathic pain. This proposal will further characterize native Kv1.2 AS RNA in the DRG and determine whether and how this AS RNA contributes to neuropathic pain. In Specific Aim 1, we will examine the expression and distribution of Kv1.2 AS RNA in the DRG and define cytochemical characteristics of Kv1.2 AS RNA-containing DRG neurons in normal rats. In Specific Aim 2, we will examine whether peripheral nerve injury produces an increase in expression of Kv1.2 AS RNA and its transcription factor MZF-1 in the DRG. Furthermore, we will examine whether Kv1.2 AS RNA is up- regulated as a result of MZF-1 binding to the consensus sequence on the Kv1.2 AS gene promoter in the injured DRG after peripheral nerve injury. In Specific Aim 3, we will use a virally mediated gene transfer strategy to determine whether over-expression of Kv1.2 AS RNA specifically and selectively reduces expression of Kv1.2 mRNA and protein and total Kv current density in DRG neurons, increases DRG neuronal excitability, and leads to major symptoms of neuropathic pain in rats. We will also examine whether blocking nerve injury-induced up-regulation of Kv1.2 AS RNA in rats reverses nerve injury-induced reductions in DRG Kv1.2 expression and total Kv current density and attenuates nerve injury-induced abnormal DRG neuronal spontaneous activity and pain hypersensitivity. The proposed studies will provide major conceptual advances to our understanding of the molecular mechanism of neuropathic pain and might open a door for developing new strategies for treating neuropathic pain.