O-GlcNac Modulation of GABAergic Transmission

O-GlcNac 对 GABA 能传输的调节

• 批准号: 10754746
• 负责人: Shekinah Phillips
• 金额: $ 4万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10754746
• 关键词: Acute; Address; Affect; Allopregnanolone; Alzheimer' s Disease; Anti-Anxiety Agents; Anxiety; Award; Barbiturates; Behavior; Benzodiazepines; Binding; Biological Assay; Biology; Bipolar Disorder; Brain; Cells; Chloride Channels; Chronic; Communication; Cyclic AMP-Dependent Protein Kinases; Data; Depressed mood; Diabetes Mellitus; Diabetic mouse; Disease; Disease model; Distant; Electrophysiology (science); Endocytosis; Endocytosis Induction; Environment; Epigenetic Process; Epilepsy; Equilibrium; Exhibits; Frequencies; Functional disorder; GABA Modulators; Gene Expression; Genes; Genetic Polymorphism; Genome; Hippocampus; Histone Code; Impairment; Individual; Lead; Ligands; Link; Location; Long-Term Depression; Major Depressive Disorder; Mass Spectrum Analysis; Mediating; Mental Depression; Metabolic Diseases; Modeling; Modification; Mutation; Neurodegenerative Disorders; Neurons; Phase; Phosphorylation; Post-Translational Protein Processing; Postdoctoral Fellow; Postpartum Depression; Proteins; Publishing; Pyramidal Cells; Regulation; Reporting; Research; Research Project Grants; Role; Schizophrenia; Serine; Shapes; Site; Slice; Steroids; Synapses; Syndrome; Techniques; Testing; Therapeutic; Threonine; Training; Transfection; Transferase; Western Blotting; Work; X-linked intellectual disability; alcohol use disorder; clinically relevant; db/db mouse; diabetic; drug of abuse; epigenetic regulation; epigenome; gamma-Aminobutyric Acid; granule cell; hypnotic; in vivo; induced pluripotent stem cell; insight; mouse model; nervous system disorder; neurodevelopment; neuropsychiatric disorder; neurosteroids; novel; patch clamp; peptide O-linked N-acetylglucosamine-beta-N-acetylglucosaminidase; pharmacologic; positive allosteric modulator; receptor; receptor function; restoration; sedative; synaptic function; synaptic inhibition; therapeutic development; transcriptome; transmission process

Changes in the strength of GABAergic transmission is heavily influenced by posttranslational modifications and allosteric modulators like benzodiazepines and neurosteroids. O-GlcNAcylation (O- GlcNAc) is a post- translational modification that is tightly regulated by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), which add or remove the O-GlcNAc moiety of β–N-acetylglucosamine to Ser/Thr residues on proteins, respectively. Various neurodegenerative diseases like Alzheimer's disease (AD), and metabolic disorders like, diabetes exhibit dysregulated O-GlcNAc levels. Published reports from our lab have demonstrated that an acute increase in O-GlcNAcylation induces a long-term depression of evoked GABAAR mediated IPSCs (eIPSCs) and reduces the amplitude and frequency of spontaneous IPSC (sIPSC) in hippocampal principal cells, however the mechanism in which this occurs is unknown. Numerous studies have shown that serine phosphorylation of GABAAR can increase or decrease GABAAR currents depending on the neuron type and specific subunit. While O-GlcNAcylation modulates inhibitory GABA-gated currents, no studies have examined its interplay with serine phosphorylation on GABAergic transmission. Because the crosstalk between O-GlcNAcylation and phosphorylation affects the regulation of various proteins, the potential exists that O-OglcNAcylation and phosphorylation will interaction in the modulation of GABAAR function and the strength of inhibitory transmission. Furthermore, a potential interaction could impact how allosteric modulators effect GABAARs, since serine phosphorylation can either increase or decrease efficacy of these modulators. Studies proposed will investigate these hypotheses and will also test whether disease conditions where O- GlcNAc levels are chronically elevated lead to depressed GABAAR function that can be rescued via pharmacological inhibition of OGT. To determine O-GlcNAcylation's effect on GABAergic transmission in the presence of phosphorylation and allosteric modulators, I will use electrophysiological techniques, immunoblotting assays and mass spectrometry. Results will show whether the modulation of GABAAR function by PKA and allosteric modulators are shaped by the presence or absence of a co-occurring O- GlcNAc modification and if the restoration of O-GlcNAcylation levels in a disease models can restore the E/I balance.

GABA能传递强度的变化受到翻译后修饰和变构调节剂如苯二氮卓类和神经类固醇的严重影响。O-GlcNAc化（O-GlcNAc）是一种受O-GlcNAc转移酶（OGT）和O-GlcNAc酶（OGA）严格调控的翻译后修饰，它们分别将β-N-乙酰葡糖胺的O-GlcNAc部分添加到蛋白质上的Ser/Thr残基上或从蛋白质上的Ser/Thr残基上去除。各种神经退行性疾病如阿尔茨海默病（AD）和代谢紊乱如糖尿病表现出失调的O-GlcNAc水平。我们实验室发表的报告表明，O-GlcNAc酰化的急性增加诱导诱发的GABAAR介导的IPSC（eIPSC）的长期抑制，并降低海马主细胞中自发IPSC（sIPSC）的振幅和频率，然而，发生这种情况的机制尚不清楚。大量研究表明，GABAAR的丝氨酸磷酸化可以增加或减少GABAAR电流，这取决于神经元类型和特定亚基。虽然O-GlcNAc酰化调节抑制性GABA门控电流，但没有研究检查其与丝氨酸磷酸化对GABA能传递的相互作用。由于O-GlcNAc酰化和磷酸化之间的串扰影响多种蛋白质的调节，因此O-GlcNAc酰化和磷酸化在GABAAR功能和抑制性传递强度的调节中存在相互作用的潜力。此外，潜在的相互作用可以影响变构调节剂如何影响GABAAR，因为丝氨酸磷酸化可以增加或降低这些调节剂的功效。提出的研究将调查这些假设，并且还将测试其中O-GlcNAc水平长期升高的疾病状况是否导致GABAAR功能抑制，其可以通过OGT的药理学抑制来挽救。为了确定在磷酸化和变构调节剂存在下O-GlcNAc酰化对GABA能传递的影响，我将使用电生理学技术、免疫印迹分析和质谱法。结果将显示PKA和变构调节剂对GABAAR功能的调节是否通过存在或不存在共发生的O-GlcNAc修饰来形成，以及疾病模型中O-GlcNAc化水平的恢复是否可以恢复E/I平衡。