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

NLRP3炎性小体是一种重要的多蛋白复合物，在感染、组织损伤或细胞应激过程中，由外源性和内源性（无菌）损伤形成，其组装被认为是引发炎症的关键过程。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炎性体有关。阐明(i)其分子作用机制，（ii）调控分子；药物抑制剂是目前免疫学和炎症研究的关键挑战。我们已经确定了众所周知的信号分子布鲁顿酪氨酸激酶（BTK）在小鼠和人类NLRP3炎症小体激活中意想不到地发挥关键作用。希望靶向NLRP3炎性体的策略可能需要数年才能达到临床意义；然而，BTK作为NLRP3调节剂的发现提供了独特的机会，通过有效且耐受性良好的fda批准的抑制剂，例如ibrutinib (PCI-32765)，在已知的药理学靶点BTK水平上靶向NLRP3炎症体。为了安全地做到这一点，需要首先解决进一步的重要开放性问题：1)BTK在炎症小体激活中的分子和细胞作用的机制是什么？具体来说，BTK的酪氨酸激酶活性及其与NLRP3修饰、激活和组装相关的其他蛋白质结构域的潜在附加功能是如何参与的？2)在涉及NLRP3炎性体的无菌和非无菌炎症状态下，BTK参与炎性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如何在小鼠和人类原代细胞中使用体外分析，新颖的和细胞特异性的小鼠体内模型和患者离体分析来全面解决这些问题，详见工作计划。我们的目标是阐明BTK-NLRP3炎症小体的分子工作原理，使其能够安全地利用BTK作为靶向NLRP3调节剂的巨大翻译潜力。

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.