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，作用于八种代谢型谷氨酸 (mGlu) 亚型，在不同的大脑回路中以部分重叠的方式表达。最近的证据表明 特定的 mGlu 受体原体可以异二聚化，并在以下情况下表现出显着不同的药理学： 与同源异构体相比。这些发现为更具选择性的配体提供了重要的可能性 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 （补充供体受体共振能量转移），其中只有定义的二聚体受体对 受体激活后诱导信号。 CODA-RET 可以以同二聚体或异二聚体模式使用， 这样就可以揭示同源二聚体与异源二聚体具有差异药理学的激活配体。我们有 在 mGlu2/4 异聚体的背景下使用 CODA-RET 来证明 mGlu2 负变构 调节剂 (NAM) 可以阻断二聚体界面对 mGlu4 特异性激动剂的反应。此外， 我们发现，虽然一种结构类型的 mGlu4 正变构调节剂 (PAM) 可以增强这两种作用 mGlu4/4 同聚体和 mGlu2/4 异二聚体，另一类 mGlu4 PAM 仅增强 mGlu4/4 同聚体。 我们使用这些药理学工具来识别特定神经元回路中的输入特异性药理学， 与 mGlu4/4 相比，在皮质纹状体和丘脑皮质突触处的作用与 mGlu2/4 异二聚体一致 纹状体苍白球突触的受体，为更精确的药理干预提供了机会。 在小鼠中，在 Schaffer Collaborative-CA1 处诱发兴奋性电流并诱导长时程增强 (LTP) (SC-CA1) 海马突触被选择性 mGlu7 负变构调节剂 (NAM) 阻断， ADX71743。相比之下，mGlu7 NAM MMPIP 在异源细胞中具有与 ADX71743 相似的特征 表达 mGlu7 同聚物，无法阻断脑切片中的这些反应。我们假设这可能 由 mGlu7 与另一个 mGlu 受体原聚体异聚化而产生。由于 mGlu8 药理学已 SC-CA1突触也有报道，我们使用CODA-RET在体外研究mGlu7/8异二聚体，发现 ADX71743 阻断 mGlu7/7 同二聚体和 mGlu7/8 异二聚体的反应，而 MMPIP 仅拮抗 mGlu7/7 同二聚体的反应。使用这些化合物以及基因敲除 对于 mGlu8，我们将检验以下假设：具有与 mGlu7/8 一致的药理学特征的受体 异二聚体在海马中功能性表达。我们的目标是： 1) 定义药理学 CA1 区谷氨酸能和 GABA 能突触处 mGlu7 变构配体的分布 海马体。 2) 检验 mGlu7/8 异二聚体导致 MMPIP 不敏感的假设 SC-CA1 反应中的表型。 3) 阐明其激活机制和信号传导特性 使用 CODA-RET 分析 mGlu7/7 同二聚体、mGlu8/8 同二聚体和 mGlu7/8 异二聚体。