Gao Tang, Yi Luyang, Wang Yihui, Wang Wenyuan, Zhao Qianqian, Song Yuan, Ding Mengdan, Deng Cheng, Chen Yihan, Xie Yuji, Wu Wenqian, Jin Qiaofeng, Zhang Li, Xie Mingxing
Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China; Hubei Province Clinical Research Center for Medical Imaging, Wuhan, 430022, China; Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China.
College of Pharmacy, Chongqing Medical University, Chongqing, 400016, China; Computational Biomedicine (IAS-5/INM-9), Forschungszentrum Jülich, Jülich, 52425, Germany.
Biosens Bioelectron. 2023 Jul 15;232:115303. doi: 10.1016/j.bios.2023.115303. Epub 2023 Apr 11.
Allograft rejection has always been a major obstacle in organ transplantation. The current clinical diagnostic gold standard for allograft rejection is an invasive biopsy. However, biopsy has some limitations, such as sampling errors, risk of serious complications, and high cost. In this study, we have rationally developed an activatable fluorescent probe CYGB for imaging of granzyme B, which is a biomarker released by CD8T cells attacking the graft. Moreover, the ability of CYGB to detect rejection early in mouse heart and skin transplantation models was evaluated. The probe CYGB consists of a caged hemicyanine-based fluorophore and a GzmB-specifically cleaved peptide substrate linked via a self-immolating spacer, p-aminobenzyl alcohol. Endogenous GzmB in CD8 T cells specifically activated the near-infrared fluorescence (NIRF) signal of CYGB. In vivo imaging in mice skin and heart graft models, showed that CYGB preferentially accumulates in grafts, enabling early diagnosis of rejection. Moreover, CYGB enables non-invasive assessment of the level of immunosuppression in allogeneic mice treated with FK506. This study provides an alternative method for monitoring the status of allografts without biopsy.
同种异体移植排斥反应一直是器官移植中的主要障碍。目前同种异体移植排斥反应的临床诊断金标准是侵入性活检。然而，活检存在一些局限性，如采样误差、严重并发症风险和高成本。在本研究中，我们合理开发了一种用于成像颗粒酶B的可激活荧光探针CYGB，颗粒酶B是CD8T细胞攻击移植物时释放的一种生物标志物。此外，还评估了CYGB在小鼠心脏和皮肤移植模型中早期检测排斥反应的能力。探针CYGB由基于笼状半花菁的荧光团和通过自毁间隔物对氨基苄醇连接的颗粒酶B特异性切割肽底物组成。CD8 T细胞中的内源性颗粒酶B特异性激活CYGB的近红外荧光（NIRF）信号。在小鼠皮肤和心脏移植模型中的体内成像显示，CYGB优先在移植物中积累，能够早期诊断排斥反应。此外，CYGB能够对用FK506治疗的同种异体小鼠的免疫抑制水平进行非侵入性评估。本研究提供了一种无需活检即可监测同种异体移植物状态的替代方法。
