MyD88 and MHCII requirement in oral Langerhans cells to drive Th17 differentiation in periodontitis

7.项目总结/摘要 牙周炎是一种慢性炎症性疾病，是牙周组织破坏的主要原因， 牙齿脱落2011年，美国治疗牙周病的费用估计为500亿美元。严重 牙周炎与口腔粘膜的牙龈卟啉单胞菌（Pg）定殖有关， 被认为是一种免疫驱动的疾病。口腔粘膜朗格汉斯细胞（oLC）对 致病性CD 4 + T辅助细胞（Th）的分化和牙槽骨破坏仍然没有解决。我们 目前的目标是确定oLCs如何驱动小鼠牙周炎中的破坏性Th 17应答 模型我们假设oLC产生Toll样受体/MyD 88依赖性扩散信号， 条件下固有层驻留树突状细胞（DC）的Th 17极化程序， 不依赖于主要组织相容性II类（MHC-II）限制性抗原呈递的方式， OLC。为了验证我们的假设，我们将使用一种新的抗原特异性四聚体来实现两个特定的目标， 确定两种突变体中Pg特异性Th和调节性CD 4 + T细胞的活化动力学和表型 小鼠品系。目的1：确定oLC中Ag：MHC-II呈递的要求，以驱动 小鼠口服Pg定植后抗原特异性Th 17细胞的分化。我们假设， oLCs通过局部“教育”固有层树突状细胞间接影响幼稚CD 4 + T细胞的极化 在粘膜中的细胞朝向分化Th 17细胞的极化程序。我们预测同源词 MHC-II：oLC和幼稚CD 4 + T细胞之间的T细胞受体相互作用不需要通过 固有层树突状细胞。因此，不能在oLC上呈递微生物MHC-II肽的小鼠， 预期区分对PG的正常Th 17型应答。 目的2：确定oLC中MyD 88依赖性信号传导的需求，以驱动oLC的分化。 抗原特异性Th 17细胞口服后的小鼠与Pg定植。我们假设MyD 88- 依赖性病原体识别信号传导诱导oLC表达旁观者炎症信号。这些 信号调节固有层树突细胞以驱动Th 17偏极化程序。我们预测 固有层树突状细胞将不能在缺乏TLR/MyD 88依赖性的小鼠中驱动Th 17极化 OLC上的信号MyD 88缺陷型oLC小鼠的预期情况是Th 1极化， 在粘膜表面遇到Pg。这种Th 1分化的情况预计将与我们所做的相同， 在缺乏oLCs的小鼠中发现了这一点。 来自R 03资助机制的数据将支持R 01应用程序，以定义oLC 驱动固有层树突细胞的局部调节。通过了解OLC在指导中所扮演的角色， 牙周病来的机会，操纵这手臂的免疫力，以实现更好的疾病 通过疫苗靶向或使用免疫疗法来干扰oLC发出的信号来获得结果。

7. PROJECT SUMMARY / ABSTRACT Periodontitis is a chronic inflammatory disease that is the leading cause of periodontal tissue destruction and tooth loss. The cost of treating periodontal diseases in the U.S. in 2011 was estimated at $50 billion. Severe periodontitis has been associated with Porphyromonas gingivalis (Pg) colonization of the oral mucosa and has been characterized as an immune-driven disease. The impact of mucosal oral Langerhans cells (oLCs) on the differentiation of pathogenic CD4+ T helper cells (Th) and alveolar bone destruction remains unresolved. Our current objective is to determine how oLCs drive a destructive Th17 response in the mouse periodontitis model. We hypothesize that oLCs produce a toll-like receptor/MyD88-dependent diffusible signal that conditions underlying lamina propria-resident dendritic cells (DCs) to a Th17 polarizing program in a manner independent of major histo-compatibility class II (MHC-II)-restricted antigen presentation by oLCs. To test our hypothesis we will pursue two specific aims using a novel antigen-specific tetramer to determine the kinetics of activation and phenotype of Pg-specific Th and regulatory CD4+ T cells in two mutant mouse strains. Aim 1: Determine the requirement of Ag:MHC-II presentation in oLCs to drive differentiation of antigen-specific Th17 cells after oral colonization of mice with Pg. We hypothesize that oLCs indirectly influence the polarization of naïve CD4+ T cells by locally “educating” lamina propria dendritic cells in the mucosae towards a polarization program that differentiates Th17 cells. We predict that cognate MHC-II:T cell receptor interaction between oLCs and naïve CD4+ T cells is not required to drive polarization by lamina propria dendritic cells. Mice unable to present microbial MHC-II peptides on oLCs are, therefore, expected to differentiate a normal Th17 type response to Pg. Aim 2: Determine the requirement of MyD88-dependent signaling in oLCs to drive differentiation of antigen-specific Th17 cells after oral colonization of mice with Pg. We hypothesize that MyD88- dependent pathogen recognition signaling induces oLCs to express bystander inflammatory signal(s). These signals condition lamina propria dendritic cells to drive a Th17-biased polarization program. We predict that lamina propria dendritic cells will be unable to drive Th17 polarization in mice lack TLR/MyD88-dependent signals on oLC. The expected scenario in MyD88-deficient oLC mice will be a Th1 polarization when encountering Pg at mucosal surfaces. This Th1-differentiation scenario is expected to be identical to what we have discovered in mice that lack oLCs. Data from this R03 funding mechanism will support an R01 application to define the mechanism by which oLCs drive local conditioning of lamina propria dendritic cells. By understanding the role played by oLCs in directing periodontal disease comes the opportunity to manipulate this arm of immunity to achieve better disease outcomes through vaccine targeting or by using immunotherapy to interfere with signals emanating from oLCs.