Enzympharmacotherapy for attenuating nicotine's psychoactive effects

项目概要/摘要。烟草成瘾是世界上第二大死亡原因， 癌症和心脏病的最大病因目前全球有13亿吸烟者 估计每年造成600万人死亡，考虑到目前的吸烟趋势，烟草将杀死1000万人。 到2020年，每年。每年，4200万成年吸烟者中有近一半试图戒烟;但由于 尼古丁具有高度成瘾性，只有不到5%的人成功。帮助戒烟包括支持 减少尼古丁奖赏和戒断的咨询、尼古丁替代和受体拮抗剂 症状不幸的是，尼古丁替代疗法的长期结果仍然很差， 第一年后的戒烟率只有10-20%。滥用药物疫苗诱导抗体， 尼古丁等药物的药理作用。到目前为止，戒烟疫苗已经显示出希望， 临床前动物模型，以证明其减少尼古丁介导的生理和行为反应的能力。 然而，在临床研究中，这些疫苗未能衡量戒烟的显着差异 在干预组和安慰剂组之间。尼古丁疫苗的致命弱点是它们无法 产生足够高的滴度（抗体浓度）以减少游离药物。鉴于与 免疫治疗，如何产生足够的药代动力学（PK）能力，以防止快速尼古丁 在吸食毒品后进入大脑的分布我们开始设想，为了克服这种令人生畏的 需要极高的尼古丁抗体滴度将需要能够分解代谢尼古丁的生物制剂， 简单地隔离药物手头的提案详细介绍了一种细菌菌株，恶臭假单胞菌， 进化到使用尼古丁作为其唯一的碳和氮来源。从该细菌菌株，我们首次公开了一种 类酶，一种尼古丁氧化还原酶（NicA 2），能高效地将尼古丁降解为 非精神药物我们对该酶的初步表征表明，它是一个很好的候选者， 我们称之为“酶药物疗法”然而，成功地展示这种策略， 戒烟治疗需要我们掌握一些挑战，我们将承担作为具体目标 包括：（1）生物化学研究作为一种手段，以解开NicA 2的作用机制和特异性。（二） 工程化NicA 2以增加其在血清中的稳定性并降低免疫原性负债。(3)评价 使用血液/脑分布和行为模型在大鼠中评估NicA 2和变体的功效。我们的研究 主动是高风险的，但是，如果成功，酶药物疗法将解决的缺点， 通过一种能够催化尼古丁降解的新生物制剂，

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. Currently there are 1.3 billion tobacco smokers worldwide resulting in an estimated 6 million deaths a year, and given present smoking trends, tobacco 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. Drug 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 with nicotine vaccines has been their inability to generate high enough titers (antibody concentration) to reduce free drug. In view of the limitations with immunotherapy, how can sufficient pharmacokinetic (PK) capacity be engendered to prevent rapid nicotine distribution into the brain after smoked drug intake? We came to envision that to overcome such forbidding needs of extremely high nicotine-antibody titers would require a biologic able to catabolize nicotine rather than simply sequestering the drug. The proposal at hand details a bacterial strain, Pseudomonas putida, which has evolved to use nicotine as its sole source of carbon and nitrogen. From this bacterial strain we disclose a first in class enzyme, a nicotine oxidoreductase (NicA2) that is highly efficient at degrading nicotine to a non-psychoactive product. Our initial characterization of the enzyme indicates it to be an excellent candidate for what we term “enzympharmacotherapy”. Yet, successful demonstration of such a strategy as a smoking cessation therapy will require mastery of a number of challenges that we will undertake as specific aims including: (1) Biochemical studies as a means to unravel NicA2's mechanism of action and specificity. (2) Engineering NicA2 to increase its stability in serum and reduce immunogenicity liabilities. (3) Evaluation of the efficacy of NicA2 and variants in rats using blood/brain distribution, and behavioral models. Our research initiative is high-risk, however, if successful, enzympharmacotherapy will address the shortcomings of antibody-based therapeutics through a new biologic capable of catalyzing nicotine's degradation.