Glia maturation factor-gamma modulation of signaling pathways in macrophages

巨噬细胞信号通路的神经胶质成熟因子-γ调节

• 批准号: 9357228
• 负责人: GRIFFIN RODGERS
• 金额: $ 58.81万
• 依托单位: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
• 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/9357228
• 关键词: Address; Adhesions; Back; Binding Proteins; Biological Process; Blood; Categories; Cell Lineage; Cell membrane; Cell surface; Cells; Chemotactic Factors; Chemotaxis; Clinic; Complex; Data; Development; Disease; Dysmyelopoietic Syndromes; Endocytosis; Erythroid; Exocytosis; Exposure to; Gene Expression Profile; Gene Expression Profiling; Genes; Genetic Transcription; Glia Maturation Factor; Global Change; Granulopoiesis; Hematopoiesis; Hematopoietic; Hematopoietic stem cells; Human; Integrins; Length; Leukemic Cell; Liquid substance; Maps; Mediating; Methods; Molecular; Molecular Profiling; Mutation; Myelogenous; Myeloproliferation; Oncogenes; Ontology; Population; Process; Proteins; Recycling; Role; Signal Pathway; Stem cells; Stromal Cell-Derived Factor 1; Structure; Suggestion; System; T-Lymphocyte; Techniques; Time; Trees; Two-Dimensional Gel Electrophoresis; Ubiquitin; Ubiquitination; cell type; gene product; knock-down; leucyl-phenylalanine; leukemia; macrophage; meetings; migration; monocyte; neutrophil; novel; overexpression; prevent; progenitor; stem; syntaxin; syntaxin 4; tool; ubiquitin mediated proteasome degradation

Monocyte migration requires the dynamic redistribution of integrins through a regulated endo-exocytosis cycle, but the complex molecular mechanisms underlying this process have not been fully elucidated. Glia maturation factor- (GMFG), a novel regulator of the Arp2/3 complex, has been shown to regulate directional migration of neutrophils and T-lymphocytes. In this study, we explored the important role of GMFG in monocyte chemotaxis, adhesion, and 1-integrin turnover. We found that knockdown of GMFG in monocytes resulted in impaired chemotactic migration toward formyl-Met-Leu-Phe (fMLP) and stromal cell-derived factor 1 (SDF-1) as well as decreased 51-integrin-mediated chemoattractant-stimulated adhesion. These GMFG knockdown impaired effects could be reversed by cotransfection of GFP-tagged full-length GMFG. GMFG knockdown cells reduced the cell surface and total protein levels of 51-integrin and increased its degradation. Importantly, we demonstrate that GMFG mediates the ubiquitination of 1-integrin through knockdown or overexpression of GMFG. Moreover, GMFG knockdown retarded the efficient recycling of 1-integrin back to the plasma membrane following normal endocytosis of 51-integrin, suggesting that the involvement of GMFG in maintaining 51-integrin stability may occur in part by preventing ubiquitin-mediated degradation and promoting 1-integrin recycling. Furthermore, we observed that GMFG interacted with syntaxin 4 (STX4) and syntaxin-binding protein 4 (STXBP4); however, only knockdown of STXBP4, but not STX4, reduced monocyte migration and decreased 1-integrin cell surface expression. Knockdown of STXBP4 also substantially inhibited 1-integrin recycling in human monocytes. These results indicate that the effects of GMFG on monocyte migration and adhesion probably occur through preventing ubiquitin-mediated proteasome degradation of 51-integrin and facilitating effective 1-integrin recycling back to the plasma membrane.

单核细胞迁移需要通过受调节的胞吐循环动态重新分配整合素，但这一过程背后的复杂分子机制尚未完全阐明。神经胶质成熟因子 (GMFG) 是 Arp2/3 复合物的一种新型调节剂，已被证明可以调节中性粒细胞和 T 淋巴细胞的定向迁移。在这项研究中，我们探讨了 GMFG 在单核细胞趋化性、粘附性和 1-整合素周转中的重要作用。我们发现，单核细胞中GMFG的敲低导致向甲酰基-Met-Leu-Phe (fMLP)和基质细胞衍生因子1 (SDF-1)的趋化迁移受损，以及51-整合素介导的趋化剂刺激的粘附减少。这些 GMFG 敲低受损效应可以通过 GFP 标记的全长 GMFG 共转染来逆转。 GMFG 敲低细胞降低了细胞表面和 51-整合素总蛋白水平，并增加了其降解。重要的是，我们证明GMFG通过GMFG的敲低或过表达来介导1-整合素的泛素化。此外，GMFG敲低阻碍了51-整合素正常内吞后1-整合素有效回收回质膜，这表明GMFG参与维持51-整合素稳定性可能部分是通过防止泛素介导的降解和促进1-整合素回收来实现的。此外，我们观察到 GMFG 与突触融合蛋白 4 (STX4) 和突触融合蛋白结合蛋白 4 (STXBP4) 相互作用；然而，只有 STXBP4 的敲低（而不是 STX4）会减少单核细胞迁移并减少 1-整合素细胞表面表达。 STXBP4 的敲除也显着抑制了人单核细胞中 1-整合素的再循环。这些结果表明，GMFG 对单核细胞迁移和粘附的影响可能是通过阻止泛素介导的 51-整合素蛋白酶体降解并促进 1-整合素有效回收回质膜而发生的。