Xiong Xinxin, Wang Danyang, Xu Liping, Chen Siyu, He Jingjing, Zhang Xiaomin, Fang Ziqian, Zhang Jianeng, Li Wende, Zhou Penghui
Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China.
Medical Research Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China.
J Immunother Cancer. 2025 May 7;13(5):e010966. doi: 10.1136/jitc-2024-010966.
The highly organized structures of the immunological synapse (IS) are crucial for T cell activation. PDZ domains might be involved in the formation of the IS by serving as docking sites for protein interactions. In this study, we investigate the role of the PALS1-associated tight junction protein (PATJ), which contains 10 PDZ domains, in the formation of IS and its subsequent impact on T cell activation.
To elucidate the function of PATJ, we generated murine models with conditional T cell-specific knockout of and assessed T cell activation both and within the context of infection and cancer. We employed confocal microscopy to visualize the formation of IS between T cells and antigen-presenting cells in the absence of . A series of PATJ truncations containing different combinations of PDZ domains was used to identify the minimal domain required for effective T cell receptor signaling. The identified active PDZ domain was then incorporated into mesothelin (MSLN)-specific chimeric antigen receptor (CAR) to evaluate its impact on CAR-T cell cytotoxicity against solid tumors.
We observed a rapid increase in PATJ expression during T cell activation. Conditional knockout of in T cells showed impaired immunity against infection and cancer in murine models. Mechanistically, ablation of impedes IS formation, and thus reduces T cell activation. We further showed that engineering the active PDZ domain of PATJ into CAR structure significantly promoted the effector function of CAR-T cells.
Our study reveals an important role of PATJ in the formation of IS and provides an approach to improve the efficacy of CAR-T therapy.
免疫突触（IS）高度有序的结构对T细胞活化至关重要。PDZ结构域可能通过作为蛋白质相互作用的对接位点参与免疫突触的形成。在本研究中，我们探究了含有10个PDZ结构域的PALS1相关紧密连接蛋白（PATJ）在免疫突触形成中的作用及其对T细胞活化的后续影响。
为阐明PATJ的功能，我们构建了条件性T细胞特异性敲除的小鼠模型，并在感染和癌症背景下评估体内和体外的T细胞活化情况。我们利用共聚焦显微镜观察在缺乏PATJ的情况下T细胞与抗原呈递细胞之间免疫突触的形成。使用一系列含有不同PDZ结构域组合的PATJ截短体来确定有效T细胞受体信号传导所需的最小结构域。然后将鉴定出的活性PDZ结构域整合到间皮素（MSLN）特异性嵌合抗原受体（CAR）中，以评估其对CAR-T细胞针对实体瘤的细胞毒性的影响。
我们观察到T细胞活化过程中PATJ表达迅速增加。T细胞中PATJ的条件性敲除在小鼠模型中显示出对感染和癌症的免疫受损。从机制上讲，PATJ的缺失阻碍了免疫突触的形成，从而降低了T细胞活化。我们进一步表明，将PATJ的活性PDZ结构域工程化到CAR结构中可显著促进CAR-T细胞的效应功能。
我们的研究揭示了PATJ在免疫突触形成中的重要作用，并提供了一种提高CAR-T治疗疗效的方法。
