Genetic Variation in Opioid Induced Respiratory Depression in Mice

项目总结/摘要 从1999年到2014年，用于治疗疼痛的阿片类药物处方几乎翻了两番， 吸毒和过量死亡在美国。吗啡和它的合成和更有效的对应物， 芬太尼，与周围和中枢神经系统中的阿片受体结合，产生镇静感觉 和欣快症。阿片样物质诱导的呼吸抑制（OIRD）由激活引起 脑干呼吸中枢神经元上阿片受体的减少可能导致心肺衰竭， 最终死亡。纳洛酮是一种用于治疗阿片类药物过量的竞争性阿片受体拮抗剂， 阿片类药物的作用，但可能会导致迅速和严重的阿片类药物戒断，这本身就是一个医疗紧急情况。 对阿片类药物的反应存在很大的个体间差异，导致对阿片类药物的敏感性存在差异。 阿片类药物过量和治疗反应。然而，这些因素和潜在机制的集合， 确定对阿片类药物的可变反应仍然未知。长期目标是定义生物学 阿片类药物过量风险的基础，并发现安全有效的新型逆转剂。的总体目标 这一建议是为了确定呼吸反应个体差异的分子机制， 表明对阿片类药物和纳洛酮的药理学替代物具有特异性敏感性的阿片类药物。初步 研究使用先进的，高多样性的小鼠种群的创始人，协作交叉（CC） 和多样性远交（DO），揭示了阿片类药物致死率和呼吸敏感性的菌株差异 将个体变异性建模为人类中的OIRD。总体目标将通过以下三个方面来实现： 具体目的：1）绘制在DO中吗啡和芬太尼敏感性的变异性的基础的遗传基因座 小鼠群体; 2）使用PiezoSleep定义CC小鼠中OIRD的深入生理成分， 体积描记法; 3）定义对吗啡和芬太尼的可变反应的机制 通过分析CC小鼠的脑干转录组。在第一个目标下，存活时间的数量性状基因座， 恢复时间和深度或呼吸抑制由于吗啡或芬太尼治疗将映射在 DO人口。在第二个目标下，将在初治， 吗啡处理和芬太尼处理的CC小鼠。在第三个目标下，将在CC小鼠中表达QTL。 映射，基因共表达网络建模将被执行，基因表达将与 表型变异拟议的研究是创新的，因为它代表了一个新的和实质性的 通过使用能够公正地发现新途径的方法， 阿片类药物过量的脆弱性和补救机制。这项研究意义重大，因为 了解阿片类药物呼吸反应变异性的机制， 阿片类药物危机通过预测阿片类药物因过量而禁忌的个体 脆弱性，并通过确定阿片受体独立逆转剂开发的目标。

PROJECT SUMMARY/ABSTRACT Prescription of opioids for treatment of pain has nearly quadrupled from 1999 to 2014 leading to an epidemic in addiction and overdose deaths in the United States. Morphine and its synthetic and more potent counterpart, fentanyl, bind to opioid receptors in the peripheral and central nervous system, producing feelings of sedation and euphoria in addition to analgesia. Opioid-induced respiratory depression (OIRD) caused by the activation of opioid receptors on neurons in the brainstem respiratory centers may lead to cardiorespiratory collapse and ultimately death. Naloxone, a competitive opioid receptor antagonist used to treat opioid overdose, blocks the effects of opioids but may cause rapid and severe opioid withdrawal, which is itself a medical emergency. There is substantial inter-individual variation in response to opioids, resulting in variation in sensitivities to opioid overdose and treatment responses. However, the collection of factors and underlying mechanisms that determine the variable responses to opioids remain unknown. The long-term goal is to define the biological basis of opioid overdose risk and to discover safe and effective novel reversal agents. The overall objective of this proposal is to define the molecular mechanisms underlying individual variability in respiratory responses to opioids that indicate specific sensitivities to opioids and pharmacological alternatives to naloxone. Preliminary studies using the founders of the advanced, high-diversity mouse populations, the Collaborative Cross (CC) and Diversity Outbred (DO), have revealed strain differences in opiate lethality and respiratory sensitivity modeling the individual variability to OIRD in humans. The overall objective will be attained by pursuing three specific aims: 1) Map genetic loci that underlie the variability in morphine and fentanyl sensitivity in the DO mouse population; 2) Define the in depth physiological components of OIRD in CC mice using PiezoSleep and plethysmography; and 3) Define the mechanisms that underlie the variable response to morphine and fentanyl by profiling the brainstem transcriptome in CC mice. Under the first aim, quantitative trait loci for survival time, recovery time and depth or respiratory depression due to morphine or fentanyl treatment will be mapped in the DO population. Under the second aim, comprehensive respiratory phenotyping will be performed in naïve, morphine-treated and fentanyl-treated CC mice. Under the third aim, expression QTL in the CC mice will be mapped, gene co-expression network modeling will be performed, and gene expression will be correlated with phenotypic variation. The proposed research is innovative because it represents a new and substantive departure from the status quo by using methods that enable unbiased discovery of new pathways and mechanisms of opioid overdose vulnerability and remediation. The proposed study is significant because understanding the mechanisms that underlie the variability in the respiratory response to opioids will address the opioid crisis both through prediction of individuals in whom opioids are contraindicated due to overdose vulnerability and through identification of targets for opioid receptor-independent reversal agent development.