Molecular Role of Bruton’s Tyrosine Kinase (BTK) in NLRP3 Inflammasome Activation

NLRP3炎症体是在感染、组织损伤或细胞应激过程中受到外源性和内源性(无菌)伤害而形成的一种关键的多蛋白复合体，其组装被认为是启动炎症的关键过程。例如，人类的多种疾病，从葡萄球菌感染到糖尿病，再到缺血性中风或心脏病发作，都与NLRP3炎症有关。阐明(I)其分子作用机制；(Ii)调节分子；(Iii)药理抑制剂是目前免疫学和炎症研究的关键挑战。我们已经确定众所周知的信号分子Bruton的酪氨酸激酶(BTK)在小鼠和人类的NLRP3炎症体激活中出人意料地发挥关键作用。希望靶向NLRP3炎症体的策略可能需要数年时间才能达到临床意义；然而，BTK作为NLRP3调节剂的发现提供了独特的机会，通过有效和耐受性良好的FDA批准的抑制剂，例如伊布鲁替尼(pCI-32765)，在众所周知的药理靶点BTK的水平靶向NLRP3炎症体。为了安全地做到这一点，首先需要解决更多重要的开放问题：1)BTK在炎症小体激活中的分子和细胞作用机制是什么？具体地说，BTK的酪氨酸激酶活性以及与NLRP3修饰、激活和组装相关的其他蛋白结构域的潜在附加功能是如何参与NLRP3的修饰、激活和组装的？2)在涉及NLRP3炎症体的无菌和非无菌炎症状态下，BTK参与炎症体激活的体内意义和治疗潜力是什么？我们在这里描述了我们希望如何利用对小鼠和人类原代细胞的体外分析、新的和细胞特异性的小鼠体内模型和患者体外分析来全面解决工作计划中详细描述的这些问题。我们的愿景是阐明BTK-NLRP3炎症体的分子工作原理，使其能够安全地利用BTK作为靶向NLRP3调节剂的可观翻译潜力。

The NLRP3 inflammasome has emerged a critical multi-protein complex formed upon exogenous and endogenous (sterile) insults during infection, tissue damage or cellular stress and its assembly has been considered a key process in initiating inflammation. For example, multiple diseases in humans, ranging from Staphylococcal infections to diabetes to ischemic stroke or heart attack, have been linked to the NLRP3 inflammasome. The elucidation of (i) its molecular mechanism of action, (ii) regulatory molecules; and (iii) pharmacological inhibitors are key challenges in immunology and inflammation research at current. We have identified the well-known signaling molecule Bruton’s Tyrosine Kinase (BTK) to unexpectedly play a critical role in NLRP3 inflammasome activation in both mice and humans. Strategies hoping to target the NLRP3 inflammasome are probably years from reaching clinical significance; however, the discovery of BTK as an NLRP3 regulator offers the unique opportunity to target the NLRP3 inflammasome at the level of a well-known pharmacological target, BTK, via efficacious and well-tolerated FDA-approved inhibitors, e.g. ibrutinib (PCI-32765). To safely do so, further vital open questions need to be addressed first: 1) What is the mechanistic molecular and cellular role of BTK in inflammasome activation? Specifically, how are the tyrosine kinase activity of BTK and potential additional functions related to its other protein domains involved in NLRP3 modification, activation and assembly? 2) What is the in vivo significance and therapeutic potential of BTK’s involvement in inflammasome activation in sterile and non-sterile inflammatory states involving the NLRP3 inflammasome? We describe here how we would like to employ in vitro analyses in murine and human primary cells, novel and cell-specific murine in vivo models and patient ex vivo analyses to comprehensively address these questions as detailed in the work program. Our vision is to elucidate the molecular workings of the BTK-NLRP3 inflammasome to a level that will allow for safely harnessing the considerable translational potential of BTK as a targetable NLRP3 regulator.