Discovery of new allosteric modulators that convert antagonists to agonists

发现将拮抗剂转化为激动剂的新型变构调节剂

基本信息

批准号：
8665402
负责人：
HORACE LOH
金额：
$ 19万
依托单位：
UNIVERSITY OF MINNESOTA
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-06-01 至 2015-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8665402
关键词：
Adenylate Cyclase Adverse effects Affinity Agonist Allosteric Site Analgesics Area Binding Binding Sites Biological Assay Cells Chemicals Chronic Dependence Development Drug Addiction Drug abuse Drug effect disorder Exhibits Fluorescence Resonance Energy Transfer Knock-in Mouse Libraries Ligand Binding Ligands Link MAPK3 gene MS4A1 gene Measurement Measures Mediating Medical Mental Depression Modification Molecular Conformation Morphine Mus Mutate Mutation Naloxone Naltrexone Narcotic Antagonists Opioid Opioid Analgesics Opioid Receptor Overdose Oxymorphone Pain Pain management Pathway interactions Pharmaceutical Preparations Relative (related person)Reporter Research Respiration Role Side Site Specificity Structure Tail Testing Therapeutic Index Therapeutic Uses Transmembrane Domain United States Ventilatory Depression Virus base chronic pain design drug candidate drug development high throughput screening in vivo mu opioid receptors mutant naltrindole neural circuit novel novel strategies opiate alkaloid overdose death pharmacophore prescription opioid public health relevance receptor receptor binding response sensor social stigma success

项目摘要

DESCRIPTION (provided by applicant): Opioids are the most efficacious compounds in the treatment of moderate to severe pain. However, with chronic use, many adverse effects including tolerance and dependence development will result. Differential tolerance development between the analgesic and respiration depression responses decreases the therapeutic index of opioids during chronic administration, which is a major concern. In order to overcome this obstacle, the holy grail of opioid research has been the development of an ideal analgesic, i.e., one that has minimal side effects, including tolerance and dependence development. Instead of developing specific orthosteric ligands that will activate a single receptor regardless of the oligomeric state of the receptor, we have pursued a novel approach to develop an opioid receptor mutant that can be activated by the opioid antagonist. This approach was based on our accidental discovery that mutation of Ser196 residue in the 4th transmembrane domain of mu-opioid receptor (OPRM1) results in the ability of opiate alkaloid antagonists such as naloxone and naltrexone to activate the receptor, without altering ligand afinity or agonist activity. This antagonist activity was demonstrated in vivo with a S196A knock-in mouse line and also with the adenoassociated virus- mediated delivery of the mutant receptor to various sites of the pain pathway. Importantly, chronic administration of naloxone in activating this mutant receptor does not result in tolerance development. The success of the OPRM1 mutant leads us to hypothesize that there must be allosteric modulators that can convert OPRM1 into conformations similar to that converted by the S196A mutation. We term such modulators as antagonist to agonist modulators or AAMs. The "proof of concept" for the existence of AAMs activity was established by our recent identification of 10 probable "hits" in our screens of 50,000 compounds in a library using a cell-based assay. Encouraged by these observations, we propose to (1) continue our screens of a chemical compound library for the existing of additional AAM activities; (2) validate the AAM activity in the identified "hits" with other OPRM1 activity measurements, such as inhibition of adenylyl cyclase activity, induction of K+ current via activation of GIRK channels, and activation of ERK1/2. Studies to demonstrate that the "hits" are actual allosteric modifiers of OPRM1 will be carried out also; and (3) to test for in vivo AAM activity by measuring the antinociceptive activity of the OPRM1 antagonist naloxone in the presence of such "hits". The current proposed studies will be the initial steps in our development of allosteric modulators for OPRM1, and will validate our hypothesis that there is a new class of allosteric modulators, AAMs. AAMs will represent a novel class of drug molecules that can limit tolerance development during chronic opioid administration, thereby maintaining the therapeutic index of the opioid analgesic treatment paradigm.

描述（由申请人提供）：阿片类药物是治疗中度至严重疼痛的最有效化合物。但是，通过长期使用，将导致许多不利影响，包括耐受性和依赖性发展。镇痛和呼吸抑郁反应之间的差异耐受性发展降低了慢性给药过程中阿片类药物的治疗指数，这是一个主要问题。为了克服这一障碍，阿片类药物研究的圣杯是一种理想的镇痛药的发展，即具有最小副作用（包括宽容和依赖性发展）的镇痛作用。我们没有开发特定的直角配体，这些配体会激活单个受体，而不论受体的低聚状态，我们采用了一种新的方法来开发阿片类药物突变体，该方法可以由阿片类药物拮抗剂激活。这种方法是基于我们意外发现的，即Mu-Apioid受体的第四个跨膜结构域（OPRM1）的突变导致阿片类生物碱拮抗剂（如纳拉武酮和奈美）的能力，例如在不改变Ligand Afinity或Agonist活性的情况下激活受体。该拮抗剂活性在体内与S196A敲入小鼠系，以及腺关系相关的病毒介导的突变受体递送到疼痛途径的各个部位。重要的是，慢性纳洛酮在激活该突变受体时不会导致耐受性的发展。 OPRM1突变体的成功使我们假设必须有变构调节剂可以将OPRM1转换为类似于S196A突变转化的构象。我们将这种调节剂称为拮抗剂与激动剂调节剂或AAM。我们最近使用基于细胞的测定法在库中50,000种化合物的屏幕中对AAMS活动的存在的“概念证明”建立了。在这些观察结果的鼓励下，我们建议（1）继续我们的化合物库的屏幕，以实现其他AAM活动；（2）用其他OPRM1活性测量值验证鉴定的“命中”中的AAM活性，例如抑制腺苷酸环化酶活性，通过激活GIRK通道的激活以及ERK1/2的激活来诱导K+电流。研究表明“命中”是实际的变构修饰符 OPRM1也将进行；（3）通过在存在这种“命中”的情况下测量OPRM1拮抗剂纳洛酮的抗伤害感受活性来测试体内AAM活性。当前提出的研究将是我们为OPRM1开发变构调节剂的初步步骤，并将验证我们的假设，即有一类新的变构调节剂AAM。 AAM将代表一类新的药物分子，该药物分子可以限制慢性阿片类药物给药期间的耐受性发展，从而维持阿片类镇痛治疗范式的治疗指数。