Advancing the therapeutic potential of a nicotine-degrading enzyme

项目摘要/摘要。烟草成瘾是世界上第二大致死原因， 癌症和心脏病的单一最大原因。鉴于目前的吸烟趋势，烟草使用将导致1000万人死亡 到2020年，每年的人口数量都会增加。每年，4200万成年吸烟者中有近一半试图戒烟；然而，由于 尼古丁具有高度成瘾性，成功率不到5%。帮助戒烟包括支持性戒烟 咨询、尼古丁替代和减少尼古丁奖赏和戒断的受体拮抗剂 症状。不幸的是，尼古丁替代疗法的长期效果仍然很差，并实现了 第一年后的禁酒率只有10%-20%。滥用药物疫苗诱导抗体阻断 尼古丁等药物的药理作用。到目前为止，用于戒烟的疫苗在 临床前动物模型的能力，以减少尼古丁介导的生理和行为反应。 然而，在临床研究中，这些疫苗未能衡量戒烟的显著差异 在干预组和安慰剂组之间。尼古丁疫苗的致命弱点是它们不能 持续产生高抗体浓度以减少流通中的游离药物。一种能够 分解代谢尼古丁，而不是简单地隔离药物，可以克服尼古丁的缺点。 疫苗。这项拟议的研究详细介绍了一种细菌菌株，恶臭假单胞菌，它已经进化到使用尼古丁 作为其碳和氮的唯一来源。从这个细菌菌株中分离出一种一流的酶，一种 尼古丁氧化还原酶(Nica2)，能高效地将尼古丁降解为非精神活性产品。 对该酶的表征表明，它是尼古丁戒断治疗的极佳候选药物。然而， 要成功演示这种策略，需要对酶进行改进，如 目的包括：(1)改造NicA2以增加其在血清中的稳定性，降低免疫原性风险。 (2)评价NicA2对非依赖型和非依赖型尼古丁增强特性的影响 对烟草使用障碍具有高预测有效性的啮齿动物模型。我的提案将采用现有的 减轻尼古丁精神活性影响的酶策略并设计一种临床可行的 尼古丁戒断的治疗方法。

Project Summary/Abstract. Tobacco addiction is the second leading cause of death in the world and the single largest cause of cancer and heart disease. Given present smoking trends, tobacco use will kill 10 million people each year by 2020. Each year nearly half of the 42 million adult smokers attempt to quit; yet, due to the highly addictive nature of nicotine, less than 5% succeed. Aids to smoking cessation include supportive counseling, nicotine replacement and receptor antagonists that reduce nicotine reward and withdrawal symptoms. Unfortunately, long-term outcomes for nicotine replacement therapies remain poor and achieve an abstinence rate of only 10-20% after the first year. Drugs of abuse vaccines induce antibodies that block the pharmacological effects of drugs like nicotine. To date, vaccines for smoking cessation have shown promise in preclinical animal models for their ability to diminish nicotine-mediated physiological and behavioral responses. However, in clinical studies these vaccines failed to measure significant differences in smoking abstinence between the intervention and placebo groups. The Achilles' heel of nicotine vaccines has been their inability to consistently generate high antibody concentrations to reduce circulating free drug. A biologic capable of catabolizing nicotine, rather than simply sequestering the drug, could overcome the shortcomings of a nicotine vaccine. The proposed study details a bacterial strain, Pseudomonas putida, which has evolved to use nicotine as its sole source of carbon and nitrogen. From this bacterial strain, was isolated a first-in-class enzyme, a nicotine oxidoreductase (NicA2), that is highly efficient at degrading nicotine to a non-psychoactive product. Characterization of the enzyme indicates it to be an excellent candidate for nicotine cessation therapy. Yet, successful demonstration of such a strategy will require improvement of the enzyme as outlined in specific aims including: (1) Engineering NicA2 to increase its stability in serum and reduce immunogenicity liabilities. (2) Evaluating the effect of NicA2 on the reinforcing properties of nicotine in non-dependent and dependent rodent models with high predictive validity for tobacco use disorder. My proposal will take an existing enzymatic strategy for the attenuation of nicotine's psychoactive effects and engineer a clinically viable therapeutic for nicotine cessation.