Keratinocyte TLR in Cutaneous Immunity

描述(申请人提供)：表皮是抵御皮肤微生物感染的第一道防线。我们最近报道，人角膜上皮细胞以及人和小鼠角质形成细胞能够表达最近描述的受体家族，称为Toll样受体(Toll-like Receptor，TLRs)。到目前为止，大多数已发表的研究都检测了TLR在白细胞中的表达和功能。对于TLR在角质形成细胞等非白细胞中的作用，我们知之甚少。在这项应用中，我们将利用体外和体内的小鼠模型系统来检验以下假设：1)角质形成细胞TLR2和TLR4在宿主皮肤对革兰氏(+)和革兰氏(-)病原体金黄色葡萄球菌和铜绿假单胞菌的防御中发挥重要作用。2)这些保护性的抗菌反应是通过金黄色葡萄球菌和铜绿假单胞菌的特定成分激活角质形成细胞TLR2和TLR4来介导的，金黄色葡萄球菌和铜绿假单胞菌的特定成分启动了强大的抗微生物天然免疫效应蛋白的局部表达和产生。3)角质形成细胞TLR2和TLR4的表达或功能缺陷将导致表皮对金黄色葡萄球菌和铜绿假单胞菌的天然免疫保护反应改变，从而可能导致进行性皮肤感染过程，导致这些细菌病原体的全身传播导致发病率增加，甚至死亡。这些假说将在以下特定目标中进行验证：特定目标1：检测培养的小鼠角质形成细胞对革兰氏(+)和革兰氏(-)细菌的反应中TLR2和TLR4的表达和功能，来自这些细菌的结构成分，以及选定的促炎和免疫抑制药物。具体目的#2：评估特定的TLR2和TLR4介导的培养小鼠角质形成细胞对致病革兰氏(+)和革兰氏(-)细菌及其结构成分的天然免疫反应。特定目的#3：确定小鼠角质形成细胞TLR2和TLR4在介导宿主对革兰氏(+)和革兰氏(-)细菌感染和细菌衍生成分的保护性表皮天然免疫反应中的作用。小鼠角质形成细胞对致病细菌的反应将与对皮肤共生细菌的反应进行比较，并在人类角质形成细胞中得到证实。我们相信，我们的研究将导致对皮肤天然免疫和皮肤中广泛的炎症性和感染性疾病的管理的新见解。

DESCRIPTION (provided by applicant): The epidermis is the first line of defense against microbial infections of the skin. We recently reported that human corneal epithelial cells as well as human and murine keratinocytes are capable of expressing a family of recently described receptors termed Toll-like receptors (TLRs). To date, most published studies have examined the expression and function of TLR in leukocytes. Much less is known about the role of TLR in non-leukocytes such as keratinocytes. In this application we will utilize both an in vitro and in vivo murine model system to test the following hypotheses : 1) Keratinocyte TLR2 and TLR4 play an essential role in host cutaneous defenses to the gram (+) and gram (-) pathogens Staphylococcus aureus and Pseudomonas aeruginosa. 2) These protective anti-bacterial responses are mediated by activation of keratinocyte TLR2 and TLR4 by specific components of Staphylococcus aureus and Pseudomonas aeruginosa that initiate the local expression and production of potent antimicrobial innate immune effector proteins. 3) Defects in the expression or function of keratinocyte TLR2 and TLR4 will result in altered epidermal innate immune protective responses to S. aureus and P. aeruginosa that may lead to a progressive cutaneous infectious process causing increased morbidity and even death as a result of systemic spread of these bacterial pathogens. These hypotheses will be tested in the following specific aims: Specific Aim #1: To examine the expression and function of TLR2 and TLR4 in cultured murine keratinocytes in response to gram (+) and gram (-) bacteria, structural components derived from these bacteria, as well as selected proinflammatory and immunosuppressive agents. Specific Aim #2: To assess selected TLR2 and TLR4 mediated innate immune responses in cultured murine keratinocytes in response to pathogenic gram (+) and gram (-) bacteria and structural components derived from these bacteria. Specific Aim #3: To determine the in vivo role of murine keratinocyte TLR2 and TLR4 in mediating host protective epidermal innate immune responses to gram (+) and gram (-) bacterial infection and bacterial-derived components. Murine keratinocyte responses to pathogenic bacteria will be compared to responses to cutaneous commensal bacteria and confirmed in human keratinocytes. We believe that our studies will lead to novel insights into cutaneous innate immunity and the management of a wide range of inflammatory and infectious diseases in the skin.