The role of MMP activity in T cells during influenza virus pathogenesis

描述(由申请人提供)：本申请中提出的研究将调查以下总体假设：基质金属蛋白酶(MMPs)活性在T细胞迁移中发挥关键作用，从而导致对流感病毒的免疫，但高剂量或高毒力感染后的异常反应可能使T细胞来源的MMPs成为病理因素。流感病毒每年都会导致重大疾病和死亡，表现为季节性反复流行和零星的破坏性大流行。高致病性流感病毒的有效性被归因于强大和异常的炎症反应，这可能导致人类严重的免疫病理损害和死亡，就像H5N1病毒一样。T细胞可通过直接溶解感染细胞和产生促炎细胞因子而导致肺损伤。T细胞向炎症部位的迁移及其效应反应是实现免疫的关键步骤，但也可能导致与致病菌株相关的高发病率和死亡率。我们假设T细胞有效地穿过肺内皮细胞屏障并穿过基底膜的能力是其功能所必需的，这是由MMPs调节的。MMPs具有蛋白水解性，能够调节构成基底膜的胶原网的裂解。T细胞可以表达MMPs，这些分子的失调可能会产生深远的后果。尽管基质金属蛋白酶活性与多种肺部疾病有关，但关于基质金属蛋白酶在调节体内T细胞对流感病毒的反应方面的功能尚不清楚。在这项应用中，我们将研究T细胞中的基质金属蛋白酶活性是否与它们在流感病毒作用下跨肺基底膜的迁移有关，从而使T细胞介导的病理发展成为可能。我们将通过过继转移因遗传缺陷(MMP2和MMP9基因敲除)或通过抑制(通过逆转录病毒转导而被击倒)而缺乏MMP活性的T细胞，来研究不同T细胞亚群中MMPs表达对其功能的相对贡献。此外，我们还将确定在体内诱导基质金属蛋白酶表达的因素。我们将集中于LFA/ICAM相互作用，它调节肺内CD4/CD8T细胞的迁移以及外源性细胞因子产生的影响，因为它与病理学有关。两者均可在体外诱导T细胞的基质金属蛋白酶活性。对基质金属蛋白酶在流感病毒致病过程中T细胞功能中的作用(S)的新发现可以阐明免疫与病理之间的平衡，因此可能具有相当大的治疗意义。与公共卫生相关的流感病毒每年会导致重大疾病和死亡，表现为季节性反复流行和零星的破坏性大流行。这项拟议研究的目标是调查流感病毒感染期间免疫病理学发展的基础反应。这些研究将为调节对流感病毒的免疫提供新的见解，并可能提供治疗临床症状的策略。

DESCRIPTION (provided by applicant): The research proposed in this application will investigate the overall hypotheses that matrix metalloprotease (MMP) activity has a critical role in the migration of T cells that leads to immunity to influenza virus, but that aberrant responses after high dose or highly virulent infections could make T cell-derived MMPs a factor in pathology. Influenza viruses cause significant annual illness and death with recurrent seasonal epidemics and sporadic devastating pandemics. The efficiency of highly pathogenic influenza viruses has been attributed to potent and aberrant inflammatory responses, which can result in severe immunopathological damage and death in humans, as found with the H5N1 virus. T cells can contribute to pulmonary damage by direct lysis of infected cells and the production of pro-inflammatory cytokines. Migration of T cells into the site of inflammation and their effector responses in situ are crucial steps towards immunity, but could also contribute to the high morbidity and mortality associated with pathogenic strains. We hypothesize that the ability of T cells to efficiently cross the lung endothelial barrier and move through the basement membrane, which is essential for their function, is regulated by MMPs. MMPs have the proteolytic capability to mediate cleavage of the collagen network that makes up the basement membrane. T cells can express MMPs and dysregulation of these molecules could have far-reaching consequences. Although, MMP activity has been implicated in a variety of pulmonary diseases, nothing is yet known regarding the function of MMPs in regulating the in vivo T cell response to influenza viruses. In this application we will investigate whether MMP activity in T cells accounts for their migration across the basement membrane of the lung in response to influenza virus and as such enables the development of T cell-mediated pathology. We will investigate the relative contribution of MMP expression in different T cell subpopulations to their function using adoptive transfers of T cells that lack MMP activity by genetic deficiency (MMP2 and MMP9 knock-out) or by inhibition (knock-down by retroviral transduction). In addition we will identify the factors that induce MMP expression in vivo. We will focus on the LFA/ICAM interaction, which regulates CD4/CD8 T cell migration in the lung and the effects of extrinsic cytokine production, since it is associated with pathology. Both can elicit MMP activity in T cells ex vivo. The discovery of new insights into the role(s) of MMP in T cell function during influenza virus pathogenesis could elucidate the balance between immunity and pathology and may therefore have considerable therapeutic relevance. PUBLIC HEALTH RELEVANCE Influenza viruses cause significant annual illness and death with recurrent seasonal epidemics and sporadic devastating pandemics. The goal of the proposed research is to investigate the responses that underlie the development of immunopathology during influenza virus infection. These studies will provide new insights into the regulation of immunity to influenza viruses and might offer a strategy to treat clinical symptoms.