NLRP3炎症小体介导Th亚群失衡在急性髓性白血病中的作用及机制研究

Though chemotherapy has made progress for acute myeloid leukemia, many patients are non-responsed or relapsed. Chemo-resistance and immunological deregulation are the main reasons. Inflammasomes are recently-identified multi-protein complexes involved in human immunology. Inflammasomes play critical roles in cancer development and chemo-resistance, which has been shown related to the imbalance of Th subsets. Our previous study has indicated the increase of NLRP3 inflammasome molecules and Th subsets which correlated with the disease progress in AML patients. We will study the effects of NLRP3 inflammasome on Th subsets and clarify the regulation of NLRP3 on Th subsets differentiation in AML patients. We will clarify the effects of NLRP3 and Th17 on proliferation, apoptosis, cell cycle and chemo-sensitivity of AML leukemia cells. After studying the related signaling pathways, we will illuminate the detailed mechanisms of NLRP3/Th17 in AML development and chemo-resistance. Furthermore, after being up-regulated or down-regulated of NLRP3, murine AML cell line C1498.GFP will be injected into C57BL/6(H-2b) mice. Then the mice will be given chemotherapy drugs or IL-17 intervention, and we will study the effects of NLRP3/Th17 on AML development and chemo-resistance in vivo.

急性髓性白血病(AML)化疗虽已取得较大进展，但多数患者仍出现难治、复发，药物敏感性降低和机体免疫功能异常是其重要原因。炎症小体为新近发现的参与机体免疫的多蛋白复合物，在肿瘤发生发展和耐药中发挥重要作用，其机制可能与介导Th亚群失衡有关。我们前期发现，AML患者中存在NLRP3炎症小体和Th17等亚群异常升高，并与预后不良相关。本课题拟研究AML患者中NLRP3炎症小体对Th17等亚群的分化调控作用；阐明AML患者骨髓中NLRP3炎症小体及其调控的Th17等亚群，对AML细胞增殖、凋亡、周期和药物敏感性等方面作用；进一步通过研究下游相关信号通路，揭示NLRP3/Th17等亚群在AML发生发展和耐药中具体作用机制。同时上调或下调小鼠AML细胞NLRP3表达后，接种C57BL/6(H-2b)小鼠，给予化疗药物或IL-17等干预，体内研究NLRP3调控Th17等亚群在AML发生发展和耐药中作用。

急性髓性白血病（AML）是一种血液系统恶性疾病，治疗虽取得一定进展，多数患者预后仍然很差，探究其发生及耐药机制具有重大临床意义。新近发现NLRP3炎症小体与肿瘤的发生发展相关，然而其在AML中的作用仍不清楚。本课题通过临床标本、体外和体内试验，探究NLRP3炎症小体在AML骨髓中的作用及相关机制。研究发现，NLRP3炎症小体相关分子NLRP3、IL-1β、NF-κB和IL-1R的mRNA水平在AML患者骨髓单个核细胞（BMMCs）中显著升高，且AML患者骨髓上清中IL-1β浓度明显增加，同时AML患者BMMCs的NLRP3炎症小体蛋白水平升高；另外AML患者BMMCs和THP1细胞系的NLRP3炎症小体经LPS、LPS+ATP活化后，包括IL-1β 在内的NLRP3组份的表达显著增加。利用贝叶斯网络模型分析提示，NLRP3炎症小体在初诊AML患者骨髓中活化可能通过NF-κB和IL-1β/IL-1R来发挥作用。进一步的功能试验证实：NLRP3炎症小体活化及其效应分子IL-1β均促进了初诊AML患者白血病细胞增殖并抑制凋亡，增强初诊AML患者白血病细胞对阿霉素和柔红霉素的抵抗。NLRP3活化的THP1细胞可抑制共培养白血病细胞的凋亡，IL-1β抗体可中和这种抑制效应。Caspase-1抑制剂Z-YVAD-FMK、NF-κB抑制剂Bay11-7082抑制了NLRP3炎症小体活性后，可引起Caspase-1、IL-1β表达减少，抑制初诊AML患者白血病细胞增殖并促进凋亡。动物实验证实：NLRP3炎症小体上调并活化小鼠AML细胞系C1498后，其NLRP3、Caspase-1、IL-1β的mRNA表达及蛋白水平明显升高，注射小鼠后，小鼠生存期较对照显著缩短。同时发现，初诊AML患者骨髓中存在免疫抑制，Th17/Treg显著降低；AML患者BMMCs中的NLRP3、Caspase-1、IL-1β与Th17转录因子AHR显著相关。因此，NLRP3炎症小体通过IL-1β/IL-1R通路在AML中发挥促癌作用，并与AML骨髓中Th亚群失衡显著相关。调控NLRP3炎症小体活性可为AML的治疗提供新的靶点。