Expression and function of discoidin domain receptor 1 in T cells

为了有效的免疫应答和到达靶组织，活化/效应T细胞必须克服血管的屏障以及基底膜和间质基质的细胞外基质（ECM），其主要由胶原蛋白构成。使用三维（3D）模型，如胶原蛋白凝胶显示，活化的T细胞使用变形运动在胶原蛋白中迁移，独立于强粘附力和整合素。在这方面，我们和其他人以前报道，盘状结构域受体1（DDR 1），酪氨酸激酶受体，结合胶原蛋白，诱导T细胞活化过程中，并参与在三维胶原蛋白中的活化的人T细胞的迁移。我们最近证明，绝大多数人Th 17细胞表达DDR 1但不表达DDR2，并且沉默DDR 1或使用阻断重组受体（DDR 1：Fc）显著降低了它们在3D胶原中的迁移。DDR 1通过激活RhoA/ROCK/MAPK/ERK信号轴促进Th 17细胞的变形运动。最后，我们表明DDR 1对于体内Th 17细胞的募集是重要的（小鼠气囊模型）。效应T细胞在血管周围组织中迁移的机制仍然知之甚少。因此，基于我们的研究，我们提出DDR 1可以是T细胞迁移和免疫应答发展中的主要受体。* 目标I：DDR 1在T细胞亚群中的表达和功能：为了进一步探索DDR 1在免疫应答中的作用，我们将检测其在人T细胞亚群中的表达和迁移功能，包括Th 1，Th 2和Th 17以及Tc 1，Tc 2和Tc 17。将表征离体和体外极化T细胞亚群。*目的II：DDR 1在T细胞存活和信号传导中的作用：除了促进细胞运动外，DDR 1还可以促进T细胞在3D胶原中的存活。因此，我们将通过确定DDR 1在3D胶原中调节T细胞凋亡和调节促凋亡和抗凋亡Bcl-2蛋白中的作用来评估这种可能性。我们还将研究MAPK，PI 3激酶/AKT和JAK/STAT途径在DDR 1介导的T细胞存活和肌动球蛋白收缩中的意义，并定义DDR 1相互作用蛋白。目标三：DDR 1在保护性免疫中的作用：为了进一步探索DDR 1在体内和免疫应答发展中的作用，我们将检查DDR 1在抗微生物免疫中的作用（S.感染）和裸鼠中的T细胞转移实验。* 重要性：这些研究将为T细胞在血管周围组织中的迁移机制以及宿主防御和保护性免疫机制带来新的见解和理解。由于细胞迁移是由所有有核细胞执行的过程，我们相信我们的研究将对理解其他过程如形态发生和组织再生产生重大影响。

For an effective immune response and to reach target tissues, activated/effector T cells must overcome the barriers of the blood vessels as well as the extracellular matrix (ECM) of the basement membrane and of the interstitial stroma, which is constituted mainly of collagen. The use of three-dimensional (3D) models such as collagen gels revealed that activated T cells use the amoeboid movement to migrate in collagen independently from strong adhesive forces and integrins. In this regard, we and others previously reported that the discoidin domain receptor 1 (DDR1), a tyrosine kinase receptor, which binds collagens, is induced during T cell activation and participates in the migration of activated human T cells in 3D collagen. We recently demonstrated that the vast majority of human Th17 cells express DDR1 but not DDR2 and that silencing DDR1 or using the blocking recombinant receptor (DDR1:Fc) significantly reduced their migration in 3D collagen. DDR1 promoted amoeboid movement of Th17 cells by activating the RhoA/ROCK/MAPK/ERK signaling axis. Finally, we showed that DDR1 is important for the recruitment of Th17 cells in vivo (mouse air pouch model). The mechanisms of effector T cell migration in perivascular tissues are still poorly understood. Thus, based on our studies, we propose that DDR1 can be a major receptor in T cell migration and in the development of immune response. ***Aim I: DDR1 expression and function in T cell subsets: To further explore the role of DDR1 in immune response, we will examine its expression and migratory function in human T cell subsets including Th1, Th2 and Th17 and Tc1, Tc2 and Tc17. Both ex-vivo and in vitro polarized T cell subsets will be characterized.***Aim II: DDR1 in T cell survival and signaling: In addition of promoting cell movement, DDR1 can also favour T cell survival in 3D collagen. Thus, we will assess this possibility by determining the role of DDR1 in the regulation of T cell apoptosis in 3D collagen and in the regulation of pro- and anti-apoptotic Bcl-2 proteins. We will also examine the implication of MAPK, PI3 kinase/AKT and JAK/STAT pathways in DDR1-mediated T cell survival and in actomyosin contraction and we will define the DDR1-interacting proteins.***Aim III: Role of DDR1 in protective immunity: To further explore the role of DDR1 in vivo and in the development of immune response, we will examine the role of DDR1 in anti-microbial immunity (mouse model of S. Pneumoniae infection) using the DDR1 KO mice and T cell transfer experiments in nude mice. ***Significance: These studies will bring new insights and understanding of the mechanisms involved in T cell migration in perivascular tissues and consequently in the mechanisms of host defense and protective immunity. Since cell migration is a process executed by all nucleated cells, we believe that our studies will have significant impact in understanding other processes such as morphogenesis and tissue regeneration.