Mechanism of intrathecal Contulakin-G induced analgesia without motor block

有效治疗高冲击性疼痛患者是国家疼痛战略的主要目标之一。尽管利用脊椎疼痛处理机制的鞘内植入给药系统对大多数顽固性疼痛患者非常有效，但它们的使用受到限制，主要是因为它们使用的药物(阿片类药物、齐康肽、局麻药)存在副作用，如耐受性、精神病和运动阻滞。新型止痛药利用脊柱疼痛处理的优势，在人类身上使用是安全的，并具有最小的运动阻滞和耐受性，在高冲击性疼痛的管理中可能是革命性的。Contulakin-G(CGX)是一种蜗牛毒源多肽，与哺乳动物神经降压素具有同源性，已被证明对人类是安全的，一项小型的中试阶段研究证实了其镇痛作用。先前发表的研究和我们的初步数据表明，鞘内注射CGX在各种顽固性疼痛条件下都是止痛的，耐受性和运动阻滞程度都很低。然而，CGX无运动阻滞镇痛的机制以及CGX引起的受体信号通路尚不清楚。我们的初步数据表明，CGX激活神经降压素受体2(NT2)以抑制R型电压门控钙通道(VGCC)。有趣的是，尽管NT2在感觉神经元和运动神经元中都存在，但R型VGCC在痛觉神经元中的表达更具选择性，可能还包括一些运动神经元。在这个项目中，我们提出了一个新的假设，即脊髓CGX产生无运动阻滞的镇痛是继发于神经降压素受体2(NT2)的CGX激活导致感觉神经元的R型VGCC抑制，而不是运动神经元。我们建议研究体外(SA1)和体内(SA2)的中心假说。我们结合了尖端科学工具，如CRISPR-Cas9编辑和邻近连接分析，以及高度验证的体外和体内分析来解决这些问题。拟议的研究测试了一个具有高度翻译意义的新假说，它们也作为一种职业发展机制，供训练有素的介入性疼痛内科医生和药剂学家指导，这些医生由经验丰富的疼痛科学家指导，具有成功的受教血统。这些研究的数据不仅将成为随后R01申请的基础，并允许申请人成为一名独立资助的临床科学家，而且有可能导致一种非阿片类药物在迫切需要缓解的患者群体中的临床进展。

Effective treatment of high-impact pain patients is one the major stated goals of the National Pain Strategy. Although implanted intrathecal drug delivery system that takes advantage of spinal pain processing mechanisms is highly effective in most intractable pain patients, their use is limited primarily because of the side effects such as tolerance, psychosis and motor block associated with drugs used in them (opioids, ziconotide, local anesthetics). Novel analgesics that take advantage of spinal pain processing, are safe to use in humans and have minimal motor block and tolerance can be revolutionary in the management of high-impact pain. Contulakin-G (CGX) is a snail venom derived peptide that has homology with mammalian neurotensin has been shown to be safe in humans and a small, pilot Phase1A study demonstrated its analgesic effect. Prior published studies and our preliminary data demonstrate that intrathecal CGX is analgesic in various intractable pain conditions with minimal tolerance and motor block. However, the mechanism behind the analgesia without motor block and the receptor signaling pathway elicited by CGX is not known. Our preliminary data suggest that CGX activates neurotensin receptor 2 (NT2) to inhibit the R-type voltage gated calcium channels (VGCC). Interestingly, although NT2 is present in both sensory and motor neurons, R-type VGCC expression is more selective in pain neurons and possibly some motor neurons. In this project, we propose to test an innovative hypothesis that spinal CGX produces analgesia without motor block is secondary to CGX activation of neurotensin receptor 2 (NT2) leading to inhibition of R-type VGCC in sensory but not motor neurons. We propose to study the central hypothesis both in vitro (SA1) and in vivo (SA2). We incorporate cutting edge scientific tools such as CRISPR-Cas9 editing and proximity ligation assay coupled with highly validated in vitro and in vivo assays to address these questions. The proposed studies test a novel hypothesis with high translational significance and they also serve as a career development mechanism for a highly trained, interventional pain physician and pharmacologist who is mentored by accomplished pain scientists with a strong pedigree of successful mentees. Data from these studies will not only form the basis of a subsequent R01 application and allow the applicant to be an independently funded clinician scientist but have the potential to lead to clinical advancement of a nonopioid drug in a patient population that desperately needs relief.