转录因子NFATc3调控巨噬细胞活化在特发性肺纤维化中的作用与机制研究

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease leading to respiratory failure and ultimately to death. It has been identified that macrophage activation plays the central role during IPF process, but the molecular and pathological mechanisms for macrophage activation to regulate IPF have not been elucidated. . Our previous study showed that NFATc3 activated in the pulmonary macrophages from mice and patients of pulmonary fibrosis , NFATc3 ablation attenuated BLM-induced pathologic alterations in pulmonary fibros and reduced production of CCL2 and IL-13 in macrophage treated with IL-13. All the above implied the povital role of NFATc3 in macrophage activation and IPF, so using the NFATc3 knockout mice, we plan to determine (1) the role of NFATc3 in BLM-induced pulmonary fibrosis and inflammation; (2) the role of macrophage in NFATc3-regulating IPF process by bone marrow transplantation and adoptive transfer experiment; (3) the signaling pathway for IL-13 to activate NFATc3 in macrophage; (4) the effect and molecular mechanism of NFATc3 on cytokines production by.macrophages. Furthermore, the activation of NFATc3 and its signaling moleculars in clinical lung tissues will be detected. . Taken together, our studies will not only elucidate the molecular pathological mechanisms that NFATc3 promotes IPF via macrophage activation, but also provide a new scientific basis and potential drug targets for therapeutic intervention of IPF.

特发性肺纤维化（IPF）是一种以炎症和纤维化为病理特点的进行性、致死性肺间质疾病，巨噬细胞在IPF病理进程中起着关键作用，但其活化和参与调控IPF的机制尚不清楚。我们前期研究发现纤维化肺巨噬细胞内转录因子NFATc3活性升高，NFATc3基因敲除后小鼠肺纤维化病理损伤减弱，IL-13诱导巨噬细胞释放的细胞因子IL-13和CCL2减少。基于此，我们提出假说；“NFATc3通过促进巨噬细胞活化参与调控特发性肺纤维化”。本研究拟采用博来霉素诱导的IPF模型，评价NFATc3在肺纤维化炎症和纤维化进程中的作用；利用骨髓移植和过继转移实验评价巨噬细胞在NFATc3调控肺纤维化中的作用；并在细胞和分子水平阐明IL-13介导NFATc3活化、促进巨噬细胞释放细胞因子的分子机制；最后在临床肺组织中进一步明确NFATc3及其信号蛋白的活化表达，为治疗肺纤维化提供新的理论依据和潜在的药物靶标。

特发性肺纤维化（IPF）是一种以早期炎症和后期纤维化为病理特征的进行性、致死性肺间质疾病，巨噬细胞在IPF进程中起着关键作用，但其活化和参与调控IPF的机制尚不清楚。大量研究揭示了NFAT在免疫调节过程中发挥着至关重要的作用，成为研究免疫抑制剂的重要靶点，但NFAT在IPF中的作用仍不清楚。本项目前期实验检测肺纤维化患者和IPF模型小鼠肺泡巨噬细胞（AMs）NFAT各亚型的活化水平变化，发现仅NFATc3在细胞核内蛋白表达水平增加，核浆比例上升，且NFATc3基因缺失时巨噬细胞表达和分泌的炎症因子和促纤维化性细胞因子降低。基于此，本项目围绕“NFATc3通过促进巨噬细胞活化参与调控特发性肺纤维化”开展研究，发现：①NFATc3在肺纤维化肺泡巨噬细胞（AMs）和肺间质巨噬细胞（IMs）中表达明显升高；②NFATc3基因表达下调时，博来霉素诱导的早期炎症和后期纤维化程度均明显减轻；③过继转移实验发现转移NFATc3+/-巨噬细胞与转移NFATc3+/+巨噬细胞相比，博来霉素诱导的肺纤维化程度明显减轻，进一步明确了NFATc3通过介导巨噬细胞促进肺纤维化；④博来霉素诱导的损伤上皮条件培养基、IL-33及IL-4+IL-13均可以诱导巨噬细胞产生CCL2、CXCL2等细胞因子，促进早期炎症反应和后期纤维化损伤；④体内实验进一步证明NFATc3基因下调后博来霉素诱导的肺组织内促炎因子TNF-α和iNOS等、促纤维化细胞因子IL-13及趋化因子CCL2和CXCL2表达均显著减少；⑤小分子天然产物可以通过抑制早期巨噬细胞活化或后期纤维化阶段巨噬细胞对成纤维细胞的活化减轻肺纤维化损伤；⑥PARP1通过表观遗传学ADP-核糖基化促进NFATc3的活化，介导巨噬细胞产生促炎因子并促进肺炎症损伤。以上研究成果为肺纤维化的防治策略提供了新的理论依据和潜在的药物靶标。