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Relevance of α-Conotoxin MII Sensitive Nicotinic Receptor Subtypes to Nicotine Addiction

α-芋螺毒素 MII 敏感烟碱受体亚型与尼古丁成瘾的相关性

基本信息

批准号：
10600540
负责人：
PAUL WHITEAKER
金额：
$ 55万
依托单位：
VIRGINIA COMMONWEALTH UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-07-01 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10600540
关键词：
Relevance Conotoxin MII Sensitive Nicotinic

项目摘要

SUMMARY / ABSTRACT α-Conotoxin MII (α-CtxMII) selectively antagonizes α3β2*- and α6β2*-nAChR. We have previously developed α6β2*-nAChR-selective α-Ctxs to define mesolimbic α6β2*-nAChR contributions to nicotine and other drug abuse phenotypes. A lack of selective compounds, and lethality in α3 nAChR null mutant mice means virtually no α3β2*-nAChR studies have been performed. Nor have extra-limbic α6β2*-nAChR contributions to addiction- relevant behaviors been investigated extensively. Therefore, we will develop α-Ctx ligands to discriminate between, characterize, and define the roles of α3β2*- and α6β2*-nAChR. The medial habenula (MH) and interpeduncular nucleus (IPN) contain the densest CNS α3β2*-nAChR populations (which outnumber MH and IPN α6β2*-nAChR). α3β4*- and α5*-nAChR in MH and IPN support nicotine dependence but ganglionic expression of α3β4*-nAChR and lack of α5*-nAChR in orthosteric binding sites may make these problematic smoking cessation targets. To establish and differentiate MH and IPN α3β2*- and α6β2*-nAChR contributions to nicotine abuse and addiction phenotype, three Specific Aims are proposed: 1) To discover further lead α-Ctx ligands with α3β2*-nAChR selectivity by screening an existing panel of >400 novel peptides, and develop them for enhanced selectivity. We have already identified 2 α-Ctx leads with >10-fold α3β2*-nAChR selectivity over other subtypes. The most-selective leads will be developed using a novel and streamlined approach to improve α-Ctx selectivity. 2) To elucidate MH and IPN α3β2*-nAChR subunit composition. We will make radio- and fluorescence-labeled derivatives of the highly-selective peptides developed in Aim 1. Using these labeled peptides, detailed α3β2*-nAChR composition will be confirmed for the first time using nAChR subunit-null mutant mice. 3) To define the importance of MH and IPN α3β2*- and α6β2*-nAChR in nicotine reinforcement and withdrawal. We will test in rats if local infusion of the selective antagonists α-CtxMII (α3β2* & α6β2*), α- CtxPIA (α6β2*-only), or a novel α3β2*-only α-Ctx into MH, IPN or 2 more control regions a) affects motivation to work for nicotine (under a progressive ratio schedule) and b) affects spontaneous somatic and behavioral withdrawal symptoms. For Aims 2 & 3, we describe how to proceed using existing compounds in the extremely unlikely case that Aim 1 does not yield suitably α3β2*-nAChR-selective α-Ctxs. This proposal's new screening and peptide-development features will radically advance future utilization of the invaluable α-Ctx resource. The resources developed in this proposal will be vital to enable future studies probing nAChR function within the addiction-related network to which MH and IPN are extensively connected. Using our novel and potent method for engineering α-Ctx selectivity in combination with refined behavioral testing across male and female subjects greatly enhances translational impact. This proposal promises to identify and characterize α3β2*-nAChR as novel, druggable, smoking therapeutic targets, and confirm α6β2*-nAChR as a viable tobacco cessation target. These advances may produce a major impact on public health by promoting smoking cessation.

总结/摘要 α-芋螺毒素MII（α-CtxMII）选择性拮抗α3β2*-和α6β2*-nAChR。我们之前开发了 α6β2*-nAChR-选择性α-Ctx，以确定中脑边缘α6β2*-nAChR对尼古丁和其他药物的贡献滥用表型缺乏选择性化合物，以及α3 nAChR无效突变小鼠的致死性意味着实际上尚未进行α3β2*-nAChR研究。也没有额外的边缘α6β2*-nAChR贡献成瘾- 相关行为进行了广泛调查。因此，我们将开发α-Ctx配体，之间，表征，并定义α3β2*-和α6β2*-nAChR的作用。内侧缰核（MH）和脚间核（IPN）含有密集的CNS α3β2*-nAChR群体（其数量超过MH， IPN α6β2*-nAChR）。MH和IPN中的α3β4*-和α5*-nAChR支持尼古丁依赖，但神经节依赖 α3β4*-nAChR的表达和α5*-nAChR在正构结合位点的缺乏可能使这些问题戒烟目标。确定和区分MH和IPN α3β2*-和α6β2*-nAChR的贡献针对尼古丁滥用和成瘾表型，提出了三个具体目标：1）进一步发现先导α-Ctx 通过筛选现有的一组>400种新型肽，并开发具有α3β2*-nAChR选择性的配体，以增强选择性。我们已经确定了2个α-Ctx先导物，其α3β2*-nAChR选择性是其他亚型。最具选择性的电极导线将使用一种新的简化方法开发，以改善 α-Ctx选择性。2)阐明MH和IPN α3β2*-nAChR亚基组成。我们要做无线电-还有目标1中开发的高选择性肽的荧光标记衍生物。使用这些标记肽，详细的α3β2*-nAChR组成将首次使用nAChR亚基-null确认突变小鼠3)确定MH和IPN α3β2*-和α6β2*-nAChR在尼古丁强化中的重要性和撤退。我们将在大鼠中测试是否局部输注选择性拮抗剂α-CtxMII（α3β2* & α 6 β 2 *）、α-CtxMII（α3β2* & α6β2*）、α-CtxMII（α3β2* & α6β2*）、α-CtxMII（α 3 β 2 *& α6 β 2 *）和α-CtxMII（α 6 β 2 *& α 6 β2*）。 CtxPIA（仅α6β2*-）或新的仅α3β2*-α-Ctx进入MH、IPN或2个以上控制区a）影响动机工作的尼古丁（根据渐进的比例计划）和B）影响自发的躯体和行为戒断症状对于目标2和3，我们描述了如何在极端条件下使用现有化合物进行不太可能的情况是，Aim 1不能产生适当的α3β2*-nAChR-选择性α-Ctx。这个提案的新筛选和肽开发功能将从根本上推动未来利用宝贵的α-Ctx资源。的在这项建议中开发的资源将是至关重要的，使未来的研究探索nAChR的功能，成瘾相关网络，MH和IPN广泛连接。用我们新颖有效的方法用于设计α-Ctx选择性，并结合男性和女性受试者的精细行为测试大大增强了翻译的影响力。该提案有望将α3β2*-nAChR鉴定和表征为新的、可药物化的吸烟治疗靶点，并证实α6β2*-nAChR是可行的戒烟靶点。这些进步可能通过促进戒烟对公共健康产生重大影响。