Synergy between TLR2 and IL-22R in airway epithelial cells during MRSA challenge

描述（由申请人提供）：革兰氏阳性菌金黄色葡萄球菌在20- 50%的人的鼻道中定植，耐甲氧西林链球菌引起的社区获得性肺炎。金黄色葡萄球菌（MRSA）正在增加。这表明需要制定疫苗接种和/或治疗策略。Toll样受体2（TLR 2）识别肽聚糖并启动对S.金黄色。树突状细胞通过产生包括IL-1b和IL-23在内的许多因子来响应TLR配体。这些细胞因子调节T细胞在称为Th 17分化的过程中产生IL-17和IL-22。白细胞介素-17和IL- 22最近被证明可以控制肺S。金黄色葡萄球菌感染（Kudva，舍勒，et al; J Immunol，in press）。目前尚不清楚哪种细胞类型必须表达TLR 2才能在体内有效产生IL-1b和IL-23，或清除MRSA。由于气道上皮细胞（AEC）表达TLR，并且是与肺部病原体接触的第一点，因此它们可能在引发炎症中发挥作用。白细胞介素-22对上皮细胞具有多种作用，包括增殖、存活和诱导抗微生物蛋白。肠上皮细胞通过产生再生胰岛衍生3（Reg 3）家族基因对IL-22作出反应，该基因可直接抑制MRSA的生长（初步数据）。在肺中，IL-22受体（IL-22 R1）仅限于AEC，并且暴露于MRSA增加了Reg 3表达（初步数据）。这些数据导致了以下假设：AEC中的TLR 2信号传导在MRSA感染期间启动Th 17细胞向肺的募集，并且还与IL-22 R协同作用以通过诱导Reg 3抗微生物凝集素介导宿主防御。具体目标1：确定肺感染S. aureus USA 300.将使用C57 BL/6和TLR 2-/-小鼠之间的骨髓嵌合体研究辐射抗性细胞如AEC中的TLR 2表达。将通过将上皮特异性Cre小鼠与IL 22 R1-floxed小鼠杂交来确定IL-22 R1在AEC中的作用。这些实验将建立TLR 2和IL-22 R1信号转导在MRSA感染期间AEC中的互补作用。具体目标2：确定Reg 3家族凝集素作为IL-22 R下游可能的效应物的作用。体外实验将确定TLR配体和IL-22是否协同诱导气管上皮细胞中的Reg 3。体内实验将检查Th 17衍生的细胞因子在Reg 3表达中的作用。Reg 3g-/-小鼠将用于阐明其在控制MRSA感染中的作用。

DESCRIPTION (provided by applicant): The gram-positive organism Staphylococcus aureus colonizes the nasal passages in 20-50 percent of people, and community-acquired pneumonia caused by methicillin-resistant S. aureus (MRSA) is increasing. This suggests a need to develop vaccination and/or treatment strategies. Toll-like receptor 2 (TLR2) recognizes peptidoglycan and initiates natural immunity to S. aureus. Dendritic cells respond to TLR ligands by producing many factors including IL-1b and IL-23. These cytokines condition T cells to produce IL-17 and IL-22 during a process called Th17 differentiation. Interleukin-17 and IL- 22 were recently shown to control lung S. aureus infection (Kudva, Scheller, et al; J Immunol, in press). It is not known which cell type(s) must express TLR2 for efficient production of IL-1b and IL-23 in vivo, or for clearance of MRSA. Since airway epithelial cells (AECs) express TLRs and are the first point of contact with lung pathogens, they could play a role in initiating inflammation. Interleukin-22 has multiple effects on epithelial cells including proliferation, survival, and induction of antimicrobial proteins. Intestinal epithelial cells respond to IL-22 by producing regenerating islet-derived 3 (Reg3) family genes, which can directly inhibit the growth of MRSA (preliminary data). In the lung, the IL-22 receptor (IL-22R1) is restricted to AECs, and exposure to MRSA increased Reg3 expression (preliminary data). These data led to the hypothesis that TLR2 signaling in AECs initiates Th17 cell recruitment to the lung during MRSA infection, and also synergizes with IL-22R to mediate host defense through the induction of Reg3 antimicrobial lectins. This hypothesis will be tested with the following aims: Specific Aim 1: Determine the roles of TLR2 and IL-22R1 expression in AECs during lung infection with S. aureus USA300. TLR2 expression in radio-resistant cells such as AECs will be studied using bone marrow chimeras between C57BL/6 and TLR2-/- mice. The role of IL-22R1 in AECs will be determined by crossing epithelial-specific-Cre mice with IL22R1-floxed mice. These experiments will establish the complementary roles of TLR2 and IL-22R1 signaling in AECs during MRSA infection. Specific Aim 2: Determine the role of Reg3 family lectins as possible effectors downstream of IL-22R. In vitro experiments will determine if TLR ligands and IL-22 synergize to induce Reg3 in tracheal epithelial cells. In vivo experiments will examine the role of Th17-derived cytokines in Reg3 expression. Reg3g-/- mice will be used to clarify its role in controlling MRSA infection.