Impact of metabotropic glutamate receptor heteromerization on signaling and pharmacology

代谢型谷氨酸受体异聚化对信号传导和药理学的影响

• 批准号: 10637938
• 负责人: Jonathan A Javitch
• 金额: $ 63.33万
• 依托单位: NEW YORK STATE PSYCHIATRIC INSTITUTE DBA RESEARCH FOUNDATION FOR MENTAL HYGIENE, INC
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-02 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10637938
• 关键词: Agonist; Area; Attention; Binding; Biology; Brain; Cells; Clinical Trials; Complement; Corpus striatum structure; Data; Electrophysiology (science); Energy Transfer; Exhibits; Genetic; Glutamate Agonist; Glutamates; Heterodimerization; Hippocampus; Homo; In Vitro; Intervention; Knock-out; Knockout Mice; Knowledge; Lead; Ligands; Long-Term Potentiation; Mediating; Mental Depression; Metabotropic Glutamate Receptors; Molecular; Mus; Neurons; Neurotransmitters; Parkinson Disease; Pharmacology; Phenotype; Property; Protomer; Receptor Activation; Reporting; Signal Transduction; Slice; Synapses; Techniques; Testing; Transactivation; Translating; Transmembrane Domain; addiction; brain tissue; dimer; gamma-Aminobutyric Acid; in vivo; neuronal circuitry; novel; optogenetics; pharmacologic; positive allosteric modulator; receptor; research clinical testing; response; tool

Glutamate, the major excitatory neurotransmitter in the brain, acts at eight metabotropic glutamate (mGlu) subtypes, expressed in a partially overlapping fashion in distinct brain circuits. Recent evidence indicates that specific mGlu receptor protomers can heterodimerize and exhibit dramatically different pharmacology when compared to their homomeric counterparts. These findings open important possibilities for more selective ligand modulation of mGlu receptor biology in the brain. To define mGlu heterodimer-specific pharmacology, we developed a technique termed CODA-RET (Complemented Donor Acceptor-Resonance Energy Transfer), in which only a defined dimeric pair of receptors induces a signal upon receptor activation. CODA-RET can be used in either homodimer or heterodimer mode, such that activating ligands with differential pharmacology at homo- vs. heterodimers can be revealed. We have used CODA-RET in the context of an mGlu2/4 heteromer to demonstrate that an mGlu2 negative allosteric modulator (NAM) can block the response to an mGlu4-specific agonist across the dimer interface. Furthermore, we showed that, while one structural class of mGlu4 positive allosteric modulators (PAMs) can potentiate both mGlu4/4 homomers and mGlu2/4 heterodimers, another class of mGlu4 PAMs potentiates only mGlu4/4 homomers. We used these pharmacological tools to identify input-specific pharmacology in specific neuronal circuits, with effects consistent with mGlu2/4 heterodimers at corticostriatal and thalamocortical synapses, versus mGlu4/4 receptors at striatopallidal synapses, providing an opportunity for more precise pharmacological intervention. In mice, evoked excitatory currents and induction of long-term potentiation (LTP) at Schaffer Collateral-CA1 (SC-CA1) synapses in the hippocampus are blocked by the selective mGlu7 negative allosteric modulator (NAM), ADX71743. In contrast, the mGlu7 NAM MMPIP, with a similar profile to ADX71743 in heterologous cells expressing mGlu7 homomers, fails to block these responses in brain slices. We hypothesized that this might result from heteromerization of mGlu7 with another mGlu receptor protomer. Since an mGlu8 pharmacology has also been reported at SC-CA1 synapses, we used CODA-RET to study mGlu7/8 heterodimers in vitro and found that ADX71743 blocks responses of both mGlu7/7 homodimers and mGlu7/8 heterodimers, whereas MMPIP only antagonizes responses at mGlu7/7 homodimers. Using these compounds, as well as genetic knockout of mGlu8, we will test the hypothesis that a receptor with a pharmacological signature consistent with an mGlu7/8 heterodimer is functionally expressed in the hippocampus. Our aims are: 1) To define the pharmacological profiles of mGlu7 allosteric ligands at glutamatergic and GABAergic synapses in area CA1 of the hippocampus. 2) To test the hypothesis that mGlu7/8 heterodimers lead to the MMPIP-insensitive phenotype in SC-CA1 responses. 3) To elucidate the activation mechanism and signaling properties of mGlu7/7 homodimers, mGlu8/8 homodimers, and mGlu7/8 heterodimers using CODA-RET.

谷氨酸是大脑中主要的兴奋性神经递质，作用于八个代谢型谷氨酸（MGLU） 亚型以不同的脑电路以部分重叠的方式表示。最近的证据表明 当特定的MGLU受体原始物体可以异二聚体并表现出明显不同的药理学。 与他们的同源物相比。这些发现开放了更具选择性配体的重要可能性 大脑中MGLU受体生物学的调节。 为了定义MGLU异二聚体特异性药理学，我们开发了一种称为Coda-Ret的技术 （补充的供体受体共振能量转移），其中只有定义的二聚体对 诱导受体激活的信号。 CODA-RET可以在同二聚体或异二聚体模式下使用， 因此，可以揭示具有差异药理学与异二聚体相对于异二聚体的激活配体。我们有 在MGLU2/4异构体的背景下使用的尾巴ret来证明MGLU2阴性变构 调制器（NAM）可以在二聚体界面上阻止对MGLU4特异性激动剂的响应。此外， 我们表明，虽然一种MGLU4阳性变构调节剂（PAM）的结构类别可以增强两者 MGLU4/4同源物和MGLU2/4异二聚体，另一类MGLU4 PAMS仅增强MGLU4/4同源物。 我们使用这些药理学工具来识别特定神经元电路中的投入特异性药理学，并具有 与MGLU2/4异二聚体一致的效果，在皮质纹状体和丘脑皮质突触上，与MGLU4/4 纹状体气质突触的受体，为更精确的药理干预提供了机会。 在小鼠中，诱发的兴奋电流和Schaffer Collat​​eral-CA1的长期增强（LTP）的诱导诱导 （SC-CA1）海马中的突触被选择性MGLU7负变构调制器（NAM），，封闭 ADX71743。相反，MGLU7 NAM MMPIP，与异源细胞中的ADX71743相似 表达MGLU7同源物，无法阻止大脑切片中的这些反应。我们假设这可能 MGLU7与另一个MGLU受体原始物质的异构化产生。由于MGLU8药理学具有 还报告了SC-CA1突触，我们使用Coda-Ret在体外研究MGLU7/8异二聚体并发现 该ADX71743阻止了MGLU7/7同二聚体和MGLU7/8异二聚体的响应，而MMPIP 仅在MGLU7/7同型二聚体时拮抗反应。使用这些化合物以及遗传敲除 在MGLU8中，我们将检验以下假设，即具有MGLU7/8一致的具有药理特征的受体 异二聚体在海马功能上表达。我们的目标是：1）定义药理 MGLU7变构配体在谷氨酸能和Gabaergic突触中Ca1区域Ca1的剖面 海马。 2）测试MGLU7/8异二聚体导致MMPIP不敏感的假设 SC-CA1响应中的表型。 3）阐明激活机制和信号传导特性 MGLU7/7同型二聚体，MGLU8/8同型二聚体和MGLU7/8异二聚体使用Coda-Ret。