Genetic Variation in Opioid Induced Respiratory Depression in Mice

项目摘要/摘要 从1999年到2014年，治疗疼痛的阿片类药物处方几乎翻了两番，导致#年流行 美国的成瘾和服药过量死亡。吗啡及其合成的更强效的对应物， 芬太尼与外周和中枢神经系统中的阿片受体结合，产生镇静感觉 以及除止痛外的欣快感。阿片类药物激活引起的呼吸抑制 脑干呼吸中枢神经元上阿片受体的变化可能导致心肺衰竭和 最终死亡。纳洛酮是一种竞争性阿片受体拮抗剂，用于治疗阿片类药物过量，可阻断 阿片类药物的作用，但可能导致快速和严重的阿片类药物戒断，这本身就是一种医疗紧急情况。 对阿片类药物的反应有很大的个体间差异，导致对 阿片类药物过量和治疗反应。然而，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上的 根据阿片类药物过量的风险，发现安全有效的新型逆转药物。总的目标是 这项建议是为了定义在呼吸反应中个体差异的分子机制 阿片类药物，表明对阿片类药物和纳洛酮的药理替代品具有特定敏感性。初步 利用高级、高多样性小鼠群体--协作杂交(CC)的创始人进行的研究 和多样性杂交(DO)，揭示了阿片剂致死性和呼吸敏感性的品系差异 将人类的个体变异性建模为OIRD。总体目标将通过三个方面来实现 具体目标：1)绘制犬吗啡和芬太尼敏感性变异的遗传基因座图 2)利用PiezoSept和PiezoSept确定CC小鼠OIRD的深层生理成分 体积描记术；以及3)确定对吗啡和芬太尼的不同反应的机制 通过对CC小鼠的脑干转录组进行分析。在第一个目标下，生存时间的数量性状基因座， 由于吗啡或芬太尼治疗而导致的恢复时间和深度或呼吸抑制将在 做好人口调查。在第二个目标下，将在天真进行全面的呼吸道表型鉴定， 吗啡处理和芬太尼处理的CC小鼠。在第三个目标下，在CC小鼠中表达QTL将是 映射后，将进行基因共表达网络建模，并将基因表达与 表型变异。拟议的研究是创新的，因为它代表了一种新的和实质性的 通过使用能够不偏不倚地发现新途径和 阿片类药物过量的易损性和补救机制。这项拟议的研究意义重大，因为 了解阿片类药物呼吸反应的变异性的机制将解决 通过预测因过量服用阿片类药物而禁药的个人，阿片类药物危机 脆弱性和通过确定阿片受体非依赖性逆转药物开发的目标。

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.