In Vivo Genetic Manipulation of Neuronal Excitability

描述(由申请人提供)： 尽管进行了多年的研究，但疼痛临床治疗的支柱仍然存在很大问题。大剂量阿片类镇痛剂副作用多，易引起耐受和依赖，具有显著的滥用潜力。然而，新的知识和技术可能会为慢性疼痛的管理提供全新的方法。 最近已经证实，有12种或更多不同的神经元钠通道，这对这些神经元传递信息的能力是至关重要的。其中一个特殊的亚型Nav1.7似乎选择性地存在于将疼痛信息从外周传递到中枢神经系统的神经元中。此外，在慢性疼痛状态下，这些通道的水平以及它们在这些神经元上的位置会发生巨大变化，这意味着它们在建立和/或维持这些疼痛状态方面很重要。因此，对Nav1.7通道功能的研究可能对设计治疗慢性疼痛的新方法具有重要意义。 为了确定这个钠通道在疼痛中的重要性，将使用病毒导向的基因转移来选择性地减少或消除NA1.7基因在那些携带疼痛信息的神经元中的表达。疱疹病毒载体以前被用来将新的转基因插入这些神经元，并减少内源性蛋白质的合成，但这种方法从未被应用于钠通道。因此，编码Nav1.7通道基因反义序列的疱疹病毒将被用来抑制该通道的产生，以便进行免疫化学、行为和电生理实验，以检验Nav1.7在疼痛生物学中的作用。通过这种方式，应该清楚这一渠道是否代表了开发新的药物工具的潜在目标。然而，这项工作的另一个含义是，这种方法本身可能提供一种治疗手段，并且有可能使用疱疹病毒载体来抑制慢性疼痛患者内源性Nav1.7通道的产生，从而为他们的疼痛提供长期的基因治疗。

DESCRIPTION (provided by applicant): Despite many years of research, the mainstays of clinical treatment of pain remain highly problematic. High dose opiate analgesics have numerous side effect, induce tolerance and dependence and have significant abuse potential. New knowledge and technologies, however, may allow for entirely new approaches to the management of chronic pain. It has recently been established that there are 12 or more different isoforms of neuronal sodium channels, which are critical to these neurons' ability to convey information. One isoform in particular, Nav1.7, appears to be selectively present in neurons that carry pain information from the periphery to the central nervous system. Furthermore, levels of these channels, as well as their location on these neurons, change dramatically during chronic pain states, implying that they are important in establishing and/or maintaining these pain states. Thus, an examination of Nav1.7 channel function may be significant in designing new approaches to the treatment of chronic pain. In order to establish the importance of this sodium channel in pain, virally directed gene transfer will be used to decrease or eliminate expression of the gene for Nav1.7 selectively in those neurons that carry pain information. Herpes viral vectors have been previously used to insert novel transgenes into these neurons, and to decrease synthesis of endogenous proteins, but this approach has never been applied to sodium channels. Thus, a herpes virus encoding an antisense sequence for the Nav1.7 channel gene will be used to knock-down production of this channel, so that immunochemical, behavioral, and electrophysiological experiments can be conducted in order to examine the contribution of Nav1.7 in pain biology. In this way, it should become clear whether or not this channel represents a potential target for the development of new pharmaceutical tools. Another implication of this work, however, is that this approach may in itself provide a means of therapy, and it may be possible to use herpes vectors to inhibit production of endogenous Nav1.7 channels in chronic pain patients, providing a long-term genetic therapy for their pain.