可逆泛素化介导的细胞自噬对非可控炎症的调控作用机制研究

Activation of nonresolving inflammation leads to continued expression of inflammatory cytokines in cells and tissues, followed with tissue damage and tumorigenesis. Recently, lots of clinical researches reveal that autophagy, a homeostatic process whereby eukaryotic cells target cellular proteins, organelles and invading microbes for degradation, plays a broad role in health and disease states, including cancer. Increasing evidence demonstrated that autophagy may be involved in the regulation of nonresolving inflammation, since many critical regulators of inflammation can be degraded through selective autophagy. However, little is known about the functions of the selective autophagy in nonresolving inflammation-mediated tumor development. The detailed molecular mechanisms about the regulation of specific inflammation regulators through selective autophagy by cargo receptors is still not clear. Our previous study also indicated that reversible ubiquitination plays an important role in the selective degradation of inflammatory regulators through autophagy, and identified several E3 ligases and deubiquitinases, including TRIM11 and USP19, which play critical roles in the crosstalk between inflammation and autophagy. In this project, we will combine the methods of immunology, molecular biology and computational biology to identify novel functions of autophagy in the regulation of nonresolving inflammation, and investigate the detailed mechanisms about how these ubiquitin-modification enzymes regulate autophagic complexes assembly or the recognition of autophagic substrates by cargo receptors to affect inflammation at molecular, cellular and animal level. Furthermore, we will attempt to draw the blueprint of the dynamic pattern of selective autophagy-mediated activation of inflammatory signaling. By using several kinds of knockout mice, we will investigate the relationship of autophagy, nonresolving inflammation and tumorigenesis in vivo. Our research will provide important data basis as well as novel drug targets for the treatment of cancer in future.

非可控炎症在肿瘤的发病进程和恶性转化中起关键作用。大量研究揭示细胞自噬与肿瘤等诸多生理病理过程密切相关。最近的研究发现细胞自噬可能参与调控非可控炎症的信号通路，许多关键炎症调控分子可通过选择性自噬降解。然而，自噬与非可控炎症及其恶性转化的关系尚不明确；由货物识别受体介导的选择性自噬降解对关键炎症分子的特异性调控的分子机制也远未被阐明。我们前期的研究揭示了可逆泛素化参与自噬对炎症反应的特异性调控，并发现TRIM11、USP19等泛素修饰分子在介导自噬和炎症调控交联中的关键作用。在本项目中，我们将结合免疫学，分子生物学和计算生物学方法，系统研究自噬在炎症激活过程中的作用和动态调控规律，绘制细胞自噬多层次调控非可控炎症的分子网络图谱；并利用多种基因敲除小鼠，探索自噬缺失对小鼠结肠组织非可控炎症及结肠肿瘤发生的影响。我们的研究将丰富现有的炎症调节理论，为改善肿瘤的治疗提供新的分子靶点和理论依据。

非可控炎症在肿瘤的发病进程和恶性转化中起关键作用。大量研究揭示细胞自噬与肿瘤等诸多生理病理过程密切相关。然而，自噬与非可控炎症及其恶性转化的关系尚不明确；由货物识别受体介导的选择性自噬降解对关键炎症分子的特异性调控的分子机制也未被阐明。我们在本项目中通过结合分子生物学、免疫学和计算生物学方法，系统研究自噬在炎症激活过程中的作用和动态调控规律，发现多个新型炎症调控分子，并绘制细胞自噬多层次调控非可控炎症的分子网络图谱，目前共取得5项重要的学术进展：（1）揭示了Tetherin/BST2通过募集E3泛素酶MARCH8，调控MAVS的泛素化，从而通过货物受体NDP52介导的选择性自噬降解负向调控免疫反应的分子机制。相关工作发表在细胞学顶尖杂志Molecular Cell上，并被Autophagy杂志专门邀请撰文介绍。（2）发现LRRC25分子作为一个自噬的二级受体，介导固有免疫的关键受体分子RIG-I和炎症的转录因子p65，通过货物受体p62进行选择性自噬降解，负向调控炎症和固有免疫，相关工作发表在EMBO J等杂志上。（3）筛选并发现一系列调控炎症和固有免疫的新分子，并深入揭示了新型Nod蛋白NLRP11通过募集RNF19A，调控TRAF6的稳定性负向调控炎症的新机制，相关工作分别发表在Science Advances和Nature Communications杂志上。（4）创造性地结合实验和计算生物学的研究方法，阐明了RIG-I多位点泛素化调控的多层次模式，并揭示该模式保证细胞抗病毒免疫反应的高效性以及下游基因转录的特异性的独特功能，相关工作发表在Science Advances杂志上。（5）系统研究了TRIM14/USP14通过可逆泛素化，调控p100/p52的稳定性和剪切，影响非经典的NF-kappaB信号通路和炎症反应的分子机制，并利用动物模型揭示其在结肠癌中的重要作用。在执行的两年间，该项目进展顺利，已完成当初制定的各项目标，在本项目支持下，本研究团队共发表学术论文13篇，申请专利4项，培养5名博士、3名硕士研究生和1名博士后。我们的研究丰富了现有的炎症调节理论，为改善肿瘤和炎症相关疾病的治疗提供了新的分子靶点和理论依据。