Regulation of RORγt in Th17-mediated inflammation

摘要 产生IL-17的Th 17细胞在许多疾病中是致病性的，包括炎症性肠病（IBD），但 对于以非炎症的方式维持肠屏障的完整性是矛盾的必需的。 然而，调节不同转录谱和功能多样性的细胞内机制， Th 17细胞仍不清楚。ROR-γt是IL-17的转录因子，在致病性和非致病性细胞中均有表达。 非致病性Th 17细胞。ROR-γt由DNA结合结构域和配体结合结构域（LBD）组成。 LBD包含激活功能2（AF 2）区，负责募集辅激活因子和辅阻遏因子 proteins. ROR-γt通常被称为“孤儿核受体”，因为其天然配体是未知的/不清楚的。我们 初步研究已经鉴定了脂筏蛋白Raftlin 1作为ROR-γt相互作用蛋白。Raftlin 1形成a 通过其保守的“LLNSL”基序与AF 2结构域结合，与ROR-γt形成复合物。通过液相色谱 结合质谱（LC-MS），我们已经确定了一些脂质种类， [溶血磷脂酰乙醇胺（LPE）、磷脂酰丝氨酸（PS）和磷脂酰胆碱（PC）]结合至 Raftlin 1和ROR-γt.基于这些新的发现，我们假设Raftlin 1作为ROR-γt的适配器， 并募集其天然脂质配体，促进Th 17的致病性。我们将在以下条件下检验这一假设： 两个目标。目的研究ROR-γ t-Raftlin 1复合物在胃肠道炎症中的作用， 2，将确定ROR-γ t-Raftlin 1复合物调控Th 17细胞致病性的机制。 随着这些研究的完成，我们期望（1）建立ROR-γ t-Raftlin 1复合物在驱动 探讨LPEs作为ROR-γt天然配体在Th 17细胞致病性中的作用 Th 7细胞

ABSTRACT Th17 cells that produce IL-17 are pathogenic in many diseases, including inflammatory bowel disease(IBD), but are paradoxically essential for maintaining the integrity of the intestinal barrier in a non-inflammatory manner. However, the intracellular mechanisms that regulate distinct transcriptional profiles and functional diversity of Th17 cells remain unclear. ROR-γt, the transcription factor for IL-17, is expressed in both pathogenic and nonpathogenic Th17 cells. ROR-γt is composed of a DNA-binding domain and a ligand-binding domain (LBD). The LBD contains the activation function 2 (AF2) region responsible for recruiting coactivator and corepressor proteins. ROR-γt is often called 'orphan nuclear receptor' because its natural ligands are unknown/unclear. Our preliminary studies have identified Raftlin1, a lipid raft protein, as a ROR-γt interacting protein. Raftlin1 forms a complex with ROR-γt by binding to the AF2 domain via its conserved 'LLNSL' motif. By liquid chromatography coupled to mass spectrometry (LC-MS), we have identified that a few lipid species [lysophosphatidylethanolamines(LPEs), Phosphatidylserines (PSs), and Phosphatidylcholines (PCs)] binds to Raftlin1 and ROR-γt. Based on these novel findings, we hypothesize that Raftlin1 acts as an adaptor for ROR-γt and recruits its natural lipid ligands, and promotes the pathogenicity of Th17. We will test this hypothesis under two aims. Aim1 will investigate the function of ROR-γt-Raftlin1 complex in gastrointestinal inflammation, and Aim 2, will determine the mechanism by which ROR-γt-Raftlin1 complex regulates the pathogenicity of Th17 cells. With the completion of these studies, we expect to (1) establish the role of ROR-γt-Raftlin1 complex in driving the pathogenicity of Th17 cells and (2) explore the function of LPEs as the natural ligands of ROR-γt in pathogenic Th7 cells.