Division of Surgical Research, University of Arkansas for Medical Sciences, Little Rock, AR.
Center for Translational Pediatric Research, Arkansas Children's Research Institute, Little Rock, AR.
Transplantation. 2021 Mar 1;105(3):540-549. doi: 10.1097/TP.0000000000003442.
Organ transplantation is life-saving and continued investigations into immunologic mechanisms that drive organ rejection are needed to improve immunosuppression therapies and prevent graft failure. DNA-dependent protein kinase catalytic subunit, DNA dependent-protein kinase catalytic subunit (DNA-PKcs), is a critical component of both the cellular and humoral immune responses. In this study, we investigate the contribution of DNA-PKcs to allogeneic skin graft rejection to potentially highlight a novel strategy for inhibiting transplant rejection.
Fully MHC mismatched murine allogeneic skin graft studies were performed by transplanting skin from BalbC mice to C57bl6 mice and treating with either vehicle or the DNA-PKcs inhibitor NU7441. Graft rejection, cytokine production, immune cell infiltration, and donor-specific antibody formation were analyzed.
DNA-PKcs inhibition significantly reduced necrosis and extended graft survival compared with controls (mean survival 14 d versus 9 d, respectively). Inhibition reduced the production of the cytokines interleukin (IL)-2, IL-4, IL-6, IL-10, TNF-α, and IFN-γ and the infiltration of CD3+ lymphocytes into grafts. Furthermore, DNA-PKcs inhibition reduced the number of CD19+ B cells and CD19+ CD138+ plasma cells coinciding with a significant reduction in donor-specific antibodies. At a molecular level, we determined that the immunosuppressive effects of DNA-PKcs inhibition were mediated, in part, via inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells signaling through reduced expression of the p65 subunit.
Our data confirm that DNA-PKcs contributes to allogeneic graft rejection and highlight a novel immunologic function for DNA-PKcs in the regulation of nuclear factor kappa-light-chain-enhancer of activated B cells and concomitant cytokine production.
器官移植是救命的，需要继续研究驱动器官排斥的免疫机制，以改善免疫抑制治疗并防止移植物衰竭。DNA 依赖性蛋白激酶催化亚基（DNA-PKcs）是细胞和体液免疫反应的关键组成部分。在这项研究中，我们研究了 DNA-PKcs 对同种异体皮肤移植物排斥的贡献，以期突出抑制移植排斥的新策略。
通过将 BalbC 小鼠的皮肤移植到 C57bl6 小鼠并分别用载体或 DNA-PKcs 抑制剂 NU7441 治疗，进行完全 MHC 错配的鼠同种异体皮肤移植研究。分析移植物排斥、细胞因子产生、免疫细胞浸润和供体特异性抗体形成。
与对照组相比，DNA-PKcs 抑制显著减少了坏死并延长了移植物的存活时间（平均存活时间分别为 14 天和 9 天）。抑制减少了细胞因子白细胞介素（IL）-2、IL-4、IL-6、IL-10、TNF-α和 IFN-γ的产生以及 CD3+淋巴细胞浸润到移植物中。此外，DNA-PKcs 抑制减少了 CD19+ B 细胞和 CD19+ CD138+浆细胞的数量，同时显著减少了供体特异性抗体。在分子水平上，我们确定 DNA-PKcs 抑制的免疫抑制作用部分是通过抑制核因子 kappa-轻链增强子的 B 细胞信号转导来介导的，这是通过减少 p65 亚基的表达来实现的。
我们的数据证实 DNA-PKcs 有助于同种异体移植物排斥，并强调了 DNA-PKcs 在调节核因子 kappa-轻链增强子的 B 细胞和伴随的细胞因子产生中的新的免疫功能。
