Characterization and Modulation of Caspase 4-Mediated Pyroptosis

项目总结/摘要 先天免疫系统是抵御内源性和外源性威胁的第一道防线， 作为效应器和激活器的双重角色。然而，当先天免疫系统对刺激的反应过于强烈时， 这会导致宿主死亡，我们常称之为“败血症。脓毒症通常与 革兰氏阴性细菌感染，如大肠杆菌。大肠杆菌或铜绿假单胞菌，并已被假设为由 它们的免疫原性物质，脂多糖（LPS）可能在这种异常的过度信号传导中起关键作用。 这项提议概述了一项研究LPS细胞内受体的计划，LPS是最近发现的一种现象， 内毒素血症的原因，虽然这种受体的确切性质的机制仍然未知。通过探测 无论是酶的激活和表征其下游蛋白水解事件，我们计划确定这种受体是否是 在人类细胞系统中LPS诱导休克的根本原因，因为敲除其鼠同源物是保护性的 内毒素休克。除了进一步表征这种细胞内的基本性质之外， LPS受体，我们将启动筛选活动，以确定选择性分子与这种酶的偏好， 与之密切相关的家庭成员。该提案产生的数据应确定一种有效的治疗方法， 逆转脓毒症和脓毒性休克的靶点，正确诊断脓毒症的生物标志物，或新的高度敏感的 用于检测血清中内毒素的测定法。

Project Summary/Abstract The innate immune system is the first-line of defense against both endogenous and exogenous threats, serving dual roles as both effectors and activators. However, when the innate immune system responds too robustly to a stimulus, this can lead to the host’s demise, a phenomenon we frequently call “sepsis”. Sepsis is frequently associated with infection by a gram-negative bacterial agent such as E. coli or P. aeruginosa and has been hypothesized to be driven by their immunogenic substances, with lipo-polysaccharide (LPS) likely playing a critical role in this aberrant over-signaling. This proposal outlines a plan to study the intracellular receptor of LPS, a recently discovered phenomenon seemingly the cause of endotoxemia, although the mechanisms underlying the exact nature of this receptor are still unknown. By probing both the enzyme’s activation and characterizing its downstream proteolytic events, we plan to identify if this receptor is the root cause of LPS-induced shock in human cell systems, as knockout of its murine homolog is protective against endotoxin shock when directly injected into mice. In addition to further characterizing the basic nature of this intracellular LPS receptor, we will initiate a screening campaign to identify selective molecules with a preference for this enzyme, over its closely related family members. The data generated by this proposal should identify either a validated therapeutic target for the reversal of sepsis and septic shock, a biomarker for the proper diagnosis of sepsis, or a new, highly sensitive assay for the detection of endotoxin in serum.