Cytotoxic lymphocytes in acute lung injury

急性肺损伤中的细胞毒性淋巴细胞

• 批准号: 6865653
• 负责人: Mitzi Nagarkatti
• 金额: $ 8.19万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-15 至 2005-08-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6865653
• 关键词: CD44 molecule; SDS polyacrylamide gel electrophoresis; T cell receptor; acute disease /disorder; bacterial antigens; bioterrorism /chemical warfare; cytotoxic T lymphocyte; enzyme linked immunosorbent assay; flow cytometry; green fluorescent proteins; immunopathology; laboratory mouse; lung injury; natural killer cells; pathologic process; polymerase chain reaction; respiratory epithelium; small interfering RNA; staphylococcal enterotoxin; staphylococcal exotoxin; wild animals

DESCRIPTION (provided by applicant): Acute lung injury (ALI) is characterized by pulmonary cellular infiltration and edema resulting from endothelial cell (EndoC) and epithelial cell (EpiC) injury, the mechanism of which remains unclear. ALI can also lead to acute respiratory distress syndrome (ARDS), which is often lethal. It occurs in several disorders affecting ~150,000 patients per year in US with a mortality rate of ~50%. One of the common features of ALI is the inflammation in the lungs and the production of cytokines. In the current investigation, we will use a mouse model of superantigen such as staphylococcal enterotoxin-induced ALI to delineate the immunopathogenesis mechanisms involved. Staphylococcal enterotoxins and other related exotoxins have been classified by the Center for Disease Control as potential biological warfare agents. It is well established that staphylococcal enterotoxins activate a large percentage of T cells expressing an invariant T cell receptor. Preliminary studies from our lab have demonstrated that staphylococcal enterotoxin B (SEB) treatment of mice led to marked upregulation of CD44 expression on lymphocytes, which migrate to the lungs and cause vascular leak by using CD44 as an effector molecule. We have shown that CD44 knock out (KO) mice are more resistant to SEB-induced pulmonary damage and furthermore, treatment of CD44 wild-type (WT) mice with antibodies against CD44 can effectively block SEB-mediated pulmonary injury. SEB treatment led to induction of IL-2, IFN-gamma and TNF-alpha production and increased NK and NKT cell infiltration in the lungs. Based on this, we will test the central hypothesis that SEB-mediated CD44 expression on cytolytic lymphocytes plays a critical role in lung injury. The specific aims of the current study are as follows: 1) To examine the role of SEB-reactive T cells, cytotoxic T cells, NK cells and NKT cells in CD44WT and CD44KO mice in induction of vascular leak and ALI. 2) CD44 bone marrow chimeras will be used to address the role of CD44 expression on cytotoxic lymphocytes, pulmonary EndoC and EpiC in SEB-induced ALI. 3) To determine the CD44 isoforms involved in lung injury by using siRNA technology 4) The role of CD44v6 and v7 isoforms in lung injury will be determined by using specific exon knockout mice 5) To develop strategies to prevent or treat lung injury using mimetics of CD44 or its ligand. Understanding the mechanism by which cytolytic lymphocytes cause alveolar EndoC and EpiC injury would help in developing novel strategies which could serve as potential biodefense against acute lung injury caused by bacterial toxins.

描述（由申请人提供）：急性肺损伤（ALI）的特征是由内皮细胞（Endoc）和上皮细胞（EPIC）损伤引起的肺细胞浸润和水肿，其机制尚不清楚。阿里还可以导致急性呼吸窘迫综合征（ARDS），这通常是致命的。 它发生在几种疾病中，每年影响约15万名患者，死亡率约为50％。 ALI的常见特征之一是肺部的炎症和细胞因子的产生。 在当前的研究中，我们将使用超抗原的小鼠模型，例如葡萄球菌肠毒素诱导的ALI来描述所涉及的免疫发病机制。 疾病控制中心将葡萄球菌肠毒素和其他相关外毒素分类为潜在的生物战剂。 众所周知，葡萄球菌肠毒素激活了表达不变T细胞受体的大部分T细胞。 我们实验室的初步研究表明，小鼠的葡萄球菌肠毒素B（SEB）治疗导致淋巴细胞上CD44表达的上调明显上调，这些表达在淋巴细胞上迁移到肺部并通过使用CD44作为效应分子引起血管泄漏。 我们已经表明，CD44敲除（KO）小鼠对SEB诱导的肺损伤具有更抗性，此外，用抗CD44的CD44野生型（WT）小鼠的治疗可以有效地阻断SEB SEB介导的肺损伤。 SEB治疗导致IL-2，IFN-GAMMA和TNF-Alpha产生的诱导，并增加了肺中NK和NKT细胞的浸润。 基于此，我们将测试中心假设，即SEB介导的CD44表达在胞糖淋巴细胞上在肺损伤中起关键作用。 当前研究的具体目的如下：1）检查CD44WT和CD44KO小鼠在诱导血管泄漏和ALI中的SEB反应T细胞，细胞毒性T细胞，NK细胞和NKT细胞的作用。 2）CD44骨髓嵌合体将用于解决CD44表达在SEB诱导的ALI中的细胞毒性淋巴细胞，肺部和史诗般的作用。 3）通过使用siRNA技术来确定参与肺损伤的CD44同工型4）CD44V6和V7同工型在肺损伤中的作用将通过使用特定的外显子基因敲除小鼠5）确定，以制定使用CD44或其配体的MIMETICENS来预防或治疗肺损伤的策略。了解细胞溶解淋巴细胞引起肺泡和史诗般损伤的机制将有助于制定新型策略，这些策略可以用作对细菌毒素引起的急性肺损伤的潜在生物脱节。