P. gingivalis Mediated Evasion Strategies

描述（由申请人提供）：许多成功的病原体已经进化出逃避宿主防御的机制，从而建立持续和慢性感染。口腔病原体牙龈卟啉单胞菌慢性感染的一个标志是诱发慢性炎症反应。尽管包括toll样受体（TLR）在内的膜结合先天免疫受体在牙龈假单胞菌的炎症反应中发挥作用，但细胞内宿主对这种病原体的防御机制如何导致持续感染并导致慢性炎症尚不清楚。我们最近报道了一种新的策略，通过牙龈卟啉菌调节参与细胞死亡和宿主防御反应的关键细胞内蛋白的水平。我们证明了P. gingivalis的赖氨酸特异性细菌半胱氨酸蛋白酶（gingipain K - Kgp）诱导受体相互作用蛋白激酶1 （RIPK1）和RIPK2的蛋白水解。我们的初步研究揭示了牙龈假单胞菌介导的RIPK降解对细胞内免疫信号反应的功能后果。这些研究支持了一个新兴的概念，即病原体介导的慢性炎症疾病是由特定的病原体介导的逃避策略导致的低级别慢性炎症。考虑到RIPK在TNF-R诱导的细胞活化和细胞内病原体感知中的作用，我们提出牙龈假单胞菌短暂降解RIPK功能的能力是一种避免细胞内先天免疫信号传导并允许细菌在靶细胞内持续存在的机制。以下具体目标将检验这一假设：目标1。定义kp介导的RIPK降解对先天免疫信号和细菌持久性的功能影响；目标2。表征RIPK裂解产物抑制NF功能的能力？B激活;目标3。在小鼠模型中，评估牙龈蛋白酶抑制剂对牙龈卟啉引起的局部慢性炎症的抑制效果；和Aim 4。在ApoE-/-小鼠模型中，评估牙龈蛋白酶抑制剂对牙龈卟啉诱导的全身慢性炎症的抑制效果。特异性阻断kgp介导的细胞激酶修饰的能力代表了一种针对宿主细胞内细菌持久性和先天免疫信号的新策略。这些研究的成功开展有可能确定和验证针对与慢性感染和由此产生的炎症后遗症相关的病原体逃避机制的新型治疗干预措施。

DESCRIPTION (provided by applicant): A number of successful pathogens have evolved mechanisms to evade host defense, thus establishing persistent and chronic infections. A hallmark of chronic infection with the oral pathogen, Porphyromonas gingivalis, is the induction of a chronic inflammatory response. Although membrane- bound innate immune receptors, including Toll-like receptors (TLR), play a role in inflammation in response to P. gingivalis, it i unknown how intracellular host defense mechanisms to this pathogen contribute to persistent infection and resulting in chronic inflammation. We have recently reported on a novel strategy by which P. gingivalis modulates the levels of key intracellular proteins involved in cell death and host defense responses. We demonstrate that the lysine-specific bacterial cysteine protease of P. gingivalis (gingipain K - Kgp) induces the proteolysis of receptor interacting protein kinase 1 (RIPK1) and RIPK2. Our preliminary studies reveal functional consequences of P. gingivalis mediated RIPK degradation on intracellular immune signaling responses. These studies support the emerging concept that pathogen-mediated chronic inflammatory disorders result from specific pathogen-mediated evasion strategies resulting in low-grade chronic inflammation. Given the roles of RIPK in TNF-R induced cell activation and sensing of intracellular pathogens, we propose the ability of P. gingivalis to transiently degrade RIPK functions as a mechanism to avoid intracellular innate immune signaling and allows for bacterial persistence within target cells. The following specific Aims will test this hypothesis: Aim 1. To define the functional consequences of Kgp-mediated RIPK degradation on innate immune signaling and bacterial persistence; Aim 2. To characterize the ability of RIPK cleaved products to function in inhibition of NF?B activation; Aim 3. To assess the efficiency of gingipain inhibitos on the inhibition of P. gingivalis-induced chronic inflammation at local sites in a murine model; and Aim 4. To assess the efficiency of gingipain inhibitors on the inhibition of P. gingivalis-induced chronic inflammation at systemic sites in an ApoE-/- murine model. The ability to specifically block Kgp-mediated modification of cellular kinases represents a novel strategy to target bacterial persistence and innate immune signaling within host cells. Successful undertaking of the proposed studies has the potential to identify and validate novel therapeutic interventions that target pathogen evasion mechanisms associated with chronic infection and the resulting inflammatory sequelae.