Characterizing the Mechanism of DPP8/9 Inhibitor-Induced Pyroptosis

项目总结 癌症免疫疗法是一种革命性的疗法，通过释放免疫系统来摧毁癌细胞。 抗击癌症的新方法。然而，尽管免疫疗法取得了前所未有的成就 在临床上，许多癌症还不能接受免疫治疗，即使对那些可以接受免疫治疗的癌症来说， 大多数患者没有反应。具有改进或补充作用机制的新药物是 因此需要。一种耐人寻味但却鲜为人知的潜在癌症免疫治疗药物是小分子 分子Val-boroPro。Val-boroPro在多种小鼠模型中诱导免疫介导的肿瘤消退 通过在单核细胞和巨噬细胞中诱导细胞程序性死亡的一种溶解形式--下垂，从而导致癌症的发生。 值得注意的是，Val-boroPro是第一个发现的诱导下垂的小分子。它现在已经建立起来了 VBP抑制胞浆丝氨酸肽酶DPP8和DPP9(DPP8/9)激活前蛋白 Caspase-1介导细胞死亡，但DPP8/9抑制如何导致caspase-1激活 仍然完全未知。该项目的长期目标是成功地利用这条道路 癌症免疫疗法。这项建议的目的是确定DPP8/9的抑制如何诱导 单核细胞和巨噬细胞的下垂。中心假说是DPP8/9裂解和失活一个 或更多的多肽，如果不切割，就会激活先天免疫传感器蛋白Nlrp1。激活的Nlrp1 然后激活原半胱氨酸天冬氨酸酶-1，触发下垂。这一假设是在以下基础上提出的 申请人实验室提供并在申请书中描述的初步数据。这一假说将 通过追求三个特定目标进行测试：1)确定菌株、物种和细胞类型对DPP8/9的敏感性 抑制剂，因为Nlrp1高度多态，在不同菌株和物种之间差异很大；2)决定 DPP8/9抑制剂激活Nlrp1的分子机制；3)决定一种特定的辅酶2的功能。 DPP8/9抑制剂诱导的下垂所需的伴侣，我们推测这是导致 关键的下垂因子(例如，Nlrp1或DPP8/9底物)的稳定性、折叠或运输。成功 这项提议的完成将揭示调节先天免疫的新原则和新机制。 系统，提供对病原体识别、自身免疫性疾病和炎症的见解。此外， 这项工作在确定新的目标和策略方面具有非凡的潜力，这些目标和策略可能成为小说的基础 癌症免疫疗法。

PROJECT SUMMARY Cancer immunotherapy – where the immune system is unleashed to destroy cancer cells – is a revolutionary new approach for combating cancer. However, even though immunotherapy has achieved unprecedented efficacies in the clinic, many cancers are not yet amenable to immune therapy, and even for those that are, a majority of patients fail to respond. New agents with improved or complementary mechanisms of action are therefore needed. One intriguing, yet poorly understood potential cancer immunotherapy agent is the small molecule Val-boroPro. Val-boroPro induces immune-mediated tumor regressions in multiple mouse models of cancer by inducing pyroptosis, a lytic form of programmed cell death, in monocytes and macrophages. Notably, Val-boroPro was the first small molecule discovered that induces pyroptosis. It is now established that inhibition of the cytosolic serine peptidases DPP8 and DPP9 (DPP8/9) by VbP activates the pro-protein form of caspase-1 to mediate cell death, but how DPP8/9 inhibition leads to the activation of caspase-1 remains entirely unknown. The long-term goal of this project is to successfully harness this pathway for cancer immunotherapy. The objective of this proposal is to determine how the inhibition of DPP8/9 induces pyroptosis in monocytes and macrophages. The central hypothesis is that DPP8/9 cleave and inactivate one or more peptides, which, if not cleaved, activates the innate immune sensor protein Nlrp1. Activated Nlrp1 then activates pro-caspase-1, triggering pyroptosis. This hypothesis has been formulated on the basis of preliminary data produced in the applicant's laboratory and described in the application. This hypothesis will be tested by pursuing three specific aims: 1) Determine strain, species, and cell type sensitivity to DPP8/9 inhibitors, as Nlrp1 is highly polymorphic and varies considerably across strains and species; 2) determine the molecular mechanism of Nlrp1 activation by DPP8/9 inhibitors; and 3) determine the function of a specific co- chaperone required for DPP8/9 inhibitor-induced pyroptosis, which we hypothesize is responsible for the stability, folding, or trafficking of a key pyroptosis factor (e.g., Nlrp1 or the DPP8/9 substrate). Successful completion of this proposal will uncover new principles and mechanisms regulating the innate immune system, providing insights into pathogen recognition, autoimmune disorders, and inflammation. Moreover, this work has extraordinary potential to identify new targets and strategies that could form the bases of novel cancer immunotherapies.