Mechanisms underlying macrophage action in nerve regeneration and degeneration

巨噬细胞在神经再生和变性中作用的机制

• 批准号: 9175255
• 负责人: RICHARD E ZIGMOND
• 金额: $ 47.31万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9175255
• 关键词: Acute; Affect; American; Animals; Autoimmune Process; Axon; Axotomy; Bacteriophages; CCL2 gene; Cells; Chemotherapy-Oncologic Procedure; Clinical; Conditioned Culture Media; Development; Diabetes Mellitus; Distal; Eating; Environment; Evaluation; Ganglia; Gene Expression; Generations; Genes; Genetic; Growth; HIV; Hereditary Disease; In Situ Hybridization; Infiltration; Injury; Intervention; Knock-out; LIF gene; Lead; Lesion; Macrophage Colony-Stimulating Factor Receptor; Measures; Mediating; Medical; Microfluidics; Mining; Modeling; Molecular; Mus; Mutant Strains Mice; Myelin; Natural regeneration; Nerve; Nerve Degeneration; Nerve Regeneration; Neurites; Neuroglia; Neurons; Peripheral; Peripheral Nervous System; Peripheral Nervous System Diseases; Peripheral nerve injury; Phagocytosis; Phenotype; Process; Reaction; Recovery; Schwann Cells; Signal Pathway; Site; Spinal Ganglia; Testing; Thinking; Trauma; Uncertainty; Virus; Wallerian Degeneration; Work; afferent nerve; axon growth; base; cell type; chemokine; chemokine receptor; chemotherapy; conditioning; cytokine; design; effective therapy; ganglion cell; hereditary neuropathy; improved; in vivo; in vivo regeneration; inhibitor/antagonist; injured; insight; knock-down; macrophage; monocyte; monocyte chemoattractant protein 1 receptor; neurite growth; neuroinflammation; neuronal cell body; novel strategies; peripheral nerve regeneration; regenerative; response; sciatic nerve; transcriptome sequencing

Peripheral nerve injury is common and occurs due to a variety of causes including trauma, diabetes, cancer chemotherapy, autoimmune reactions, and genetic disorders. Although peripheral neurons are capable of regenerating, this process is generally incomplete. It is therefore crucial to determine ways in which regener- ation can be enhanced. Macrophages are thought to promote peripheral nerve regeneration after an acute injury due to their accumulation in the distal nerve where they phagocytize axonal debris and myelin thereby creating an environment through which axons can grow. In addition, macrophages secrete cytokines that trigger growth factor synthesis in non-neuronal cells in the nerve. The absence of these actions has been assumed to be the basis for the slow regeneration that occurs in the slowly degenerating Wlds mouse. How- ever, it has been known for 20 years. In part due to our studies. that there is a second, distinct, site of mac- rophage accumulation after injury, namely, peripheral ganglia such as dorsal root ganglia (DRGs) where the axotomized cell bodies reside. What has remained unknown is what function these macrophages subserve. Recent studies from our lab represent a major advance in answering this question. Work with two mutant mouse strains, a knockout for the chemokine receptor CCR2 and the Wlds mice led to the hypothesis that macrophage accumulation in ganglia is required for the occurrence of the conditioning lesion (CL) response, the response in which neurite outgrowth after a lesion is increased as a consequence of an earlier condition- ing lesion. This application is designed to test the following overall model: macrophages brought into the DRG by the chemokine CCL2 trigger the expression of regeneration associated genes (RAGs) via the secretion of cytokines around axotomized cell bodies and this promotes the CL response and regen- eration in addition to any effects macrophages have on the distal nerve. To establish beyond doubt that CCL2-dependent macrophage accumulation and the CCL2-dependent CL response are causally related, we will use an inhibitor of colony stimulating factor 1 receptors to deplete circulating monocytes. To deter- mine whether macrophages act directly on neuronal cell bodies, we will use microfluidic chambers in which a neuron’s cell body and axon can be separated. Gene expression using RNAseq will be compared after ax- otomy in CCRs -/- and wild type animals to determine which axotomy-induced genes are dependent on mac- rophage accumulation. Since we have shown that Wallerian degeneration is normal in CCR2 -/- mice but monocyte infiltration into DRGs is blocked, these animals will allow us to determine whether macrophage accumulation in DRGs is required for sensory nerve regeneration in vivo. Using these novel approaches, we will examine the mechanisms underlying the relationship between macrophage accumulation near axoto- mized cell bodies and axonal growth. Emphasizing ganglia, unexplored sites of neuroinflammation, repre- sents a paradigm shift from the traditional view that focuses on macrophage effects on the distal nerve.

周围神经损伤很常见，并且由于包括创伤，糖尿病，癌症在内的多种原因而发生。 化学疗法，自身免疫反应和遗传疾病。尽管外周神经元能够 再生，这个过程通常不完整。因此，至关重要的是确定再生剂的方法 可以增强。巨噬细胞被认为可以促进急性后的周围神经再生 由于它们在远端神经中积累而造成的损伤，它们吞噬了轴突碎屑和髓磷脂 创造一个可以通过轴突生长的环境。此外，巨噬细胞的秘密细胞因子 触发神经非神经元细胞中的生长因子合成。这些行动的缺失已经 假定是在缓慢退化的WLDS小鼠中发生缓慢再生的基础。如何- 曾经闻名了20年。部分是由于我们的研究。 Mac-有第二个不同的位置 受伤后的r裂积累，即外周神经节，例如背根神经节（DRG） 轴化细胞体驻留。尚不清楚的是这些巨噬细胞的功能。 我们实验室的最新研究代表了回答这个问题的重大进步。与两个突变体一起工作 小鼠菌株，趋化因子受体CCR2和WLDS小鼠的敲除导致了一个假设： 发生调节病变（CL）的发生需要巨噬细胞积累，需要 由于早期条件 - 病变。该应用程序旨在测试以下整体模型：带入的巨噬细胞 DRG通过趋化因子CCL2触发了再生相关基因（RAG）的表达 细胞因子周围的细胞因子的分泌，这促进了Cl反应和再生 除了任何影响巨噬细胞对远端神经的影响外。毫无疑问地确定 CCL2依赖性巨噬细胞积累和CCL2依赖性CL响应有时是相关的， 我们将使用刺激因子1受体的抑制剂来定义循环单核细胞。确定 - 地雷巨噬细胞是否直接作用于神经元细胞体，我们将使用微流体室，其中 神经元的细胞体和轴突可以分开。在AX-之后将比较使用RNASEQ的基因表达 CCR中的口径 - / - 和野生型动物，以确定哪些轴切开术诱导的基因取决于MAC- r裂积累。由于我们已经证明沃勒式的变性在CCR2 - / - 小鼠中是正常的，但是 单核细胞渗入DRG中，这些动物将使我们能够确定巨噬细胞是否是否 在体内感觉神经再生需要DRG中的积累。使用这些新颖的方法，我们 将检查巨噬细胞在Axoto-附近的巨噬细胞积累之间关系的机制 体积的细胞体和轴突生长。强调神经节，神经炎症的意外部位，代表 从传统视图中发送范式转变，该视图的重点是巨噬细胞对远端神经的影响。