Role of LAIR-1 and CD300 Family Receptors in Regulating Inflammation

LAIR-1 和 CD300 家族受体在调节炎症中的作用

基本信息

批准号：
7732617
负责人：
John E Coligan
金额：
$ 48.17万
依托单位：
NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
依托单位国家：
美国
项目类别：
财政年份：
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/7732617
关键词：
Affect Allergic Animals Antigens B-Lymphocytes CD4 Positive T Lymphocytes CD8B1 gene Cell surface Cells Chemical Models Collagen Cytoplasmic Tail Defect Dendritic Cells Development Family Family member Gene Cluster Goals Granulocyte-Macrophage Colony-Stimulating Factor HL60 Hematopoietic stem cells Human IRp60 ITAM ITIM IgG1 Immune Immune response Immunoglobulin Class Switching Immunologic Receptors In Vitro Inflammation Intracellular translocation Ligands Ligation Light Lymphocyte Lymphoid Mediating Modeling Mus Myeloid Cells Natural Killer Cells Numbers Organ Peptides Peripheral Peritoneum Peritonitis Play Production Proliferating Proteins Publishing Reactive Oxygen Species Receptor Activation Research Personnel Role Signal Transduction Site T-Lymphocyte cell type crosslink cytotoxicity eosinophil extracellular in vivo macrophage mast cell member monocyte neutrophil peripheral blood receptor research study response toll-like receptor 4 trafficking

项目摘要

We have generated LAIR-1 -/- mice on a B6 background to study the in vivo function of LAIR-1. Phenotypic analysis of lymphoid organs did not show large differences between LAIR-1 +/+ and LAIR-1 -/- animals. We have observed a slight increase in the percentage of splenic B cells in the LAIR-1 -/- mice, along with a decrease in T cells, mostly because of a decrease in CD8 T cells. This probably does not result from abnormal trafficking of T lymphocytes, since LAIR-1 +/+ and LAIR-1 -/- T cells traffic equally to peripheral lymphoid organs. In the gut we have observed a slight increase of T cells in the LAIR-1 -/- mice, along with an increase in the NKG2D expression. In vitro experiments showed that OT-II LAIR-1-/- CD4 T cells proliferated less than the OT-II LAIR-1+/+ CD4 T cells when they are cultured with APC loaded with OT-II OVA peptide. To study the immune response in vivo, we have immunized the animals with TNP-OVA and found that class switching is affected in LAIR-1 -/- mice. These animals produced lower levels of IgG2a and IgG2b, while switching to IgG1 is not affected. By using T cell specific LAIR-1 -/- animals (CD4 Cre LAIR-1flox/flox), we confirmed that the defect in class switching is T cell specific. Previous investigators have published that mouse B cells do not express LAIR-1; however, recently we have found that marginal zone B cells are positive for LAIR-1 expression. Other preliminary results have shown that in the LAIR-1 -/- mice there are significant alterations in the recruitment of macrophages and eosinophils into the peritoneum in a model of chemical peritonitis, suggesting a role for LAIR-1 in the trafficking of these cell types towards sites of inflammation. We showed that human neutrophils from peripheral blood express CD300a. To study expression during neutrophil development, we used the HL-60 differentiation model. We showed that CD300a expression is acquired during development and that cell surface expression increases very rapidly when neutrophils are stimulated with LPS and GM-CSF. This increase is the result of translocation of an intracellular pool of the receptor to the cell surface. This ready availability of CD300a is reminiscent of CTLA-4 and suggests that CD300a could play an important role in modulating neutrophil responses. Co-ligation of CD300a with the ITAM containing CD32a (FcRIIa) activation receptor inhibited CD32a mediated signaling, whereas it did not inhibit toll-like receptor (TLR)-4 mediated reactive oxygen species (ROS) production. Therefore, at least for human neutrophils, it seems that the inhibitory signals mediated by the CD300a receptor may be selective in their action.

我们在 B6 背景下生成了 LAIR-1 -/- 小鼠来研究 LAIR-1 的体内功能。淋巴器官的表型分析未显示 LAIR-1 +/+ 和 LAIR-1 -/- 动物之间存在较大差异。我们观察到 LAIR-1 -/- 小鼠的脾 B 细胞百分比略有增加，同时 T 细胞减少，这主要是由于 CD8 T 细胞减少。这可能不是由于 T 淋巴细胞的异常运输造成的，因为 LAIR-1 +/+ 和 LAIR-1 -/- T 细胞平等地运输到外周淋巴器官。在肠道中，我们观察到 LAIR-1 -/- 小鼠的 T 细胞略有增加，同时 NKG2D 表达也有所增加。体外实验表明，当OT-II LAIR-1-/- CD4 T细胞与负载OT-II OVA肽的APC一起培养时，OT-II LAIR-1+/+ CD4 T细胞的增殖能力低于OT-II LAIR-1+/+ CD4 T细胞。为了研究体内免疫反应，我们用 TNP-OVA 对动物进行免疫，发现 LAIR-1 -/- 小鼠的类别转换受到影响。这些动物产生的 IgG2a 和 IgG2b 水平较低，而转用 IgG1 则不受影响。通过使用 T 细胞特异性 LAIR-1 -/- 动物 (CD4 Cre LAIR-1flox/flox)，我们证实类别转换的缺陷是 T 细胞特异性的。之前的研究人员已经发表过小鼠 B 细胞不表达 LAIR-1；然而，最近我们发现边缘区B细胞LAIR-1表达呈阳性。其他初步结果表明，在化学性腹膜炎模型中，LAIR-1 -/- 小鼠腹膜中巨噬细胞和嗜酸性粒细胞的募集发生了显着变化，表明 LAIR-1 在这些细胞类型的运输中发挥着作用朝向炎症部位。我们发现外周血中的人类中性粒细胞表达 CD300a。为了研究中性粒细胞发育过程中的表达，我们使用了 HL-60 分化模型。我们发现 CD300a 表达是在发育过程中获得的，并且当中性粒细胞受到 LPS 和 GM-CSF 刺激时，细胞表面表达非常迅速增加。这种增加是细胞内受体库易位至细胞表面的结果。 CD300a 的这种现成可用性让人想起 CTLA-4，并表明 CD300a 在调节中性粒细胞反应中可以发挥重要作用。 CD300a 与含有 CD32a (FcRIIa) 激活受体的 ITAM 共连接可抑制 CD32a 介导的信号传导，而不会抑制 Toll 样受体 (TLR)-4 介导的活性氧 (ROS) 产生。因此，至少对于人类中性粒细胞来说，CD300a受体介导的抑制信号似乎在其作用上可能是选择性的。