Regulation of Synaptic engulfment by human C4

人类 C4 对突触吞噬的调节

• 批准号: 9280284
• 负责人: Michael Craig Carroll
• 金额: $ 56.34万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/9280284
• 关键词: Address; Affect; Age related macular degeneration; Alleles; Amino Acids; Apoptotic; Behavioral; Binding; Brain; Chemicals; Code; Complement; Complement 3a; Complement component C4a; Cues; Dendritic Spines; Deposition; Development; Disease; Etiology; Excision; Exhibits; Gene Expression; Genes; Genetic study; Human; Immune; Inflammation; Inflammation Mediators; Inflammatory; Inherited; Lead; Link; Mediating; Mental disorders; Microglia; Modeling; Mouse Strains; Mus; Names; Neurons; Pathogenicity; Pathology; Patients; Peptides; Peripheral; Phagocytosis; Predisposition; Protein Isoforms; Proteins; Regulation; Reporting; Risk; Risk Factors; Role; Schizophrenia; Serum; Signal Transduction; Site; Synapses; System; Testing; Time; Tissues; Transgenic Mice; Variant; Visual system structure; complement system; cytokine; density; gene function; gray matter; macrophage; model design; mouse model; novel; overexpression; protein function; relating to nervous system; retinogeniculate; synaptic pruning

Project 2: How does human C4 allelic diversity affect microglia-mediated synaptic pruning? Abstract: Schizophrenia (SCZ) patients exhibit excessive loss of grey matter and decreased dendritic spine density, suggesting that abnormal synaptic pruning may contribute to SCZ etiology. Genetic studies indicate that complement C4A is a susceptibility factor for SCZ, although it is not clear if this link is a result of increased complement expression in the brain or in the periphery, or both. The complement system is a major mediator of inflammation in the periphery and over expression of C4 could induce release of pro-inflammatory cytokines that induce pathology affecting both the periphery and the CNS. The human C4 locus encodes two highly conserved isoforms named C4A (acidic) and C4B (basic) which differ overall by only four amino acid differences. The differences are functionally important in binding to target sites. In the brain, C4 localizes to synapses and is required for synaptic pruning in the developing visual system. Whether the two isoforms differ in binding efficiency to synapses has not been reported. SCZ patients express elevated levels of C4A relative to C4B in the CNS suggesting that the level of local expression of C4 in the brain may also be an important factor in disease. To help address these questions, we have developed novel strains of mice that express the common alleles of human C4, i.e. C4A only, C4B only or C4A and C4B, and crossed them to the C4-deficident background. In addition, we have used gene editing to alter the murine C4 locus to express the human C4A- or C4B-like isotypic region. Given the importance of complement C4 in synapse elimination in the murine visual system, will use these mice to test our hypothesis that chemical differences in C4 combined with increased level of local expression affect binding to synapses and directly affect the efficiency of synapse elimination by activated microglia. Two specific aims are proposed: Aim 1: How do the activities of C4A and C4B differ in the periphery and CNS? This aim will precisely define how C4A and C4B functional differences affect developmental synaptic pruning and microglia activity in the LGN. Aim 2: What are the effects of complement overexpression on synaptic pruning? This aim will test for the first time the idea that complement overactivation stimulates excessive synaptic pruning using mouse models designed to model C4A expression in SCZ.

项目2：人类C4等位基因多样性如何影响小胶质细胞介导的突触修剪？ 抽象的： 精神分裂症（SCZ）患者表现出过多的灰质损失，树突状脊柱密度降低， 表明异常突触修剪可能有助于SCZ病因。遗传研究表明 补体C4a是SCZ的敏感性因素，尽管尚不清楚此链接是否是增加的结果 补充大脑或周围的表达，或两者兼而有之。补体系统是 外围和C4表达的炎症可能诱导促炎性细胞因子释放 诱导影响周围和中枢神经系统的病理。人C4基因座编码两个高度保守的 称为C4A（酸性）和C4B（基本）的同工型，总体上仅差异四个氨基酸差异。这 差异在与目标位点的结合中在功能上很重要。在大脑中，C4本地化到突触，为 在开发的视觉系统中进行突触修剪所必需的。两种同工型在结合上是否有所不同 尚未报告突触的效率。 SCZ患者表示相对于C4B的C4B水平升高 中枢神经系统表明，大脑中C4的局部表达水平也可能是一个重要因素 疾病。为了帮助解决这些问题，我们开发了新颖的老鼠菌株，表达了共同的 人类C4的等位基因，即仅C4A，仅C4B或C4A和C4B，并将其越过C4缺陷 背景。此外，我们已经使用基因编辑来改变鼠C4基因座以表达人C4A- 或类似C4B的同种型区域。鉴于补体C4在鼠视觉中消除突触消除的重要性 系统，将使用这些小鼠来检验我们的假设，即C4的化学差异与水平增加相结合 局部表达会影响与突触的结合，并直接影响激活的突触消除效率 小胶质细胞。提出了两个具体目标： 目标1：C4A和C4B的活动在外围和CNS上有何不同？ 该目标将精确定义C4A和C4B功能差异如何影响发育性突触修剪和 LGN中的小胶质细胞活性。 目标2：补体过表达对突触修剪有什么影响？ 该目标将首次测试补充过度激活会刺激过度突触修剪的想法 鼠标旨在模拟SCZ中的C4A表达。