Endocytic Regulation of Inflammation

炎症的内吞调节

基本信息

批准号：
8972844
负责人：
LINDA H SHAPIRO
金额：
$ 40.77万
依托单位：
UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-08-01 至 2019-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8972844
关键词：
Address Animals Antiviral Response Autoimmunity Binding Cell Adhesion Molecules Cell physiology Cell surface Cells Clinical Complex Data Defect Dendritic Cells Development Disease Dissection Endocytosis Endothelial Cells Equilibrium Figs - dietary Goals Healed Health Hematopoietic ITGAX gene Immune response Immune system Impaired wound healing In Vitro Individual Inflammation Inflammatory Injury Interferon Type I Interferons Interleukin-10 Ischemia Knowledge Ligands Ligation Marrow Mediating Mission Modeling Molecular Mus Muscle Myelogenous Myeloid Cells Natural Immunity Necrosis Nitrates Obesity Organelles Outcome Pathogenesis Pathology Pathway interactions Pattern Peptide Hydrolases Perfusion Peripheral arterial disease Process Production Recovery Regulation Relative (related person)Research Role Sentinel Signal Pathway Signal Transduction Signal Transduction Pathway Site Stem cells TLR4 gene Therapeutic Tissues Toll-like receptors Transplantation United States National Institutes of Health Wound Healing alanine aminopeptidase angiogenesis arm base cell type cytokine design femoral artery genetic regulatory protein healing improved in vivo Model interest macrophage neutrophil new therapeutic target novel pathogen prevent receptor receptor mediated endocytosis receptor recycling response response to injury therapeutic target tissue repair

项目摘要

DESCRIPTION (provided by applicant): CD13 is a large, multifunctional cell surface peptidase that is constitutively expressed on all lineages of myeloid cells (among others) and upregulated on endothelial cells at sites of angiogenesis and inflammation. Collectively, our recent studies demonstrate that CD13 regulates endocytosis of receptors of disparate classes in different cell types to control downstream signal transduction pathways, implicating a role for CD13 in fundamental cellular processes. More recently, we showed that in dendritic cells (DCs) CD13 regulates endocytosis of the toll-like receptor TLR4 which is a critical sentinel of the innate immune response to pathogens via PAMPs (pathogen-associated molecular patterns) and DAMPs (danger associated molecular patterns). Binding of DAMPs to macrophage and DC TLR4 in the absence of CD13 leads to an unbalanced cytokine response and aberrantly high levels of type I interferons (IFNs) due to skewed endocytic-signaling pathways. Although beneficial in anti-viral responses, strong IFN responses clearly exacerbate the patho- genesis of TLR4-binding PAMPs and DAMPs. Furthermore, we have additional evidence implicating CD13 in receptor recycling to the cell surface. To model this in vivo we subjected wild type and CD13null animals to permanent femoral artery dissection, which releases endogenous ligands that TLR4 recognizes as DAMPs. Functionally, CD13null mice have strikingly impaired ambulation and perfusion recovery and more necrosis consistent with impaired healing. Furthermore, cytokine profiles in the ischemic muscle showed markedly increased levels of IFN-ß and IL-10 consistent with our in vitro data and with studies where TLR4 engagement by PAMPs or DAMPs leads to exaggerated pathology suggesting that CD13 regulates the balance between pro-inflammatory and IFN-generating signal transduction in myeloid cells. Furthermore, marrow transplant studies demonstrating that CD13null donor hematopoietic cells are unable to rescue perfusion and function in wild type ischemic muscles validate this notion and highlights the importance of fully understanding the mechanistic basis of this novel regulator. Finally, while it is clear that the individual subsets of myeloid cells of the innate immune response orchestrate subsequent steps in the healing process, their relative contributions and specific roles are largely unknown. Pertinent to this proposal, macrophage and DC TLR4 signaling occurs via both cell surface and endocytic mechanisms supporting discrete regulatory processes and cell-specific roles for these largely uncharacterized pathways in distinct cell types. Therefore, through its regulation of endocytosis, we propose that myeloid CD13 is a functional regulator of innate immunity and dissection of the relative contributions of CD13 expressed on pan-myeloid (lysM-cre) and DCs (CD11c-cre) to these regulatory processes will clearly increase our understanding of myeloid cells in response to ischemia, information essential to the design of strategies to regulate healing by manipulating this novel target.

描述（由申请人提供）：CD13 是一种大型多功能细胞表面肽酶，在所有骨髓细胞谱系（以及其他细胞）上组成型表达，并在血管生成和炎症部位的内皮细胞上表达上调。总的来说，我们最近的研究表明 CD13。调节不同细胞类型中不同类别受体的内吞作用，以控制下游信号转导途径，暗示 CD13 在基本细胞中的作用最近，我们发现在树突状细胞 (DC) 中，CD13 调节 Toll 样受体 TLR4 的内吞作用，TLR4 是通过 PAMP（病原体相关分子模式）和 DAMP（危险相关）对病原体进行先天免疫反应的关键哨兵。在没有 CD13 的情况下，DAMP 与巨噬细胞和 DC TLR4 的结合会导致细胞因子反应不平衡和 I 型细胞水平异常高由于内吞信号通路的倾斜，干扰素 (IFN) 显然有利于抗病毒反应，但强的 IFN 反应会加剧 TLR4 结合 PAMP 和 DAMP 的发病机制。此外，我们还有其他证据表明 CD13 参与了受体再循环。为了在体内模拟这一点，我们对野生型和 CD13null 动物进行永久性股动脉解剖，释放 TLR4 识别为 DAMP 的内源性配体。在功能上，CD13null 小鼠的行走和灌注恢复明显受损，并且坏死更多，这与愈合受损一致。此外，缺血肌肉中的细胞因子谱显示 IFN-β 和 IL-10 水平显着增加，这与我们的体外数据和 TLR4 的研究一致。 PAMP 或 DAMP 的参与导致夸张的病理学，表明 CD13 调节骨髓细胞中促炎和产生 IFN 的信号转导之间的平衡。此外，骨髓移植研究表明，CD13null 供体造血细胞无法挽救野生型缺血肌肉的灌注和功能，这验证了这一观点，并强调了充分理解这种新型调节剂的机制基础的重要性。很明显，先天免疫反应的骨髓细胞个体在愈合过程中协调后续步骤，但它们的相对贡献和具体作用在很大程度上是未知的。与该提议相关的是，巨噬细胞和 DC TLR4 信号传导通过细胞表面和内吞机制发生。在不同的细胞类型中，支持这些很大程度上未表征的途径的离散调节过程和细胞特异性作用，因此，通过其对内吞作用的调节，我们认为髓样 CD13 是先天免疫和解剖的功能调节剂。泛骨髓细胞 (lysM-cre) 和树突状细胞 (CD11c-cre) 上表达的 CD13 对这些调节过程的相对贡献将明显增加我们对骨髓细胞响应缺血的理解，这些信息对于设计调节愈合的策略至关重要操纵这个新目标。