Simultaneous Diagnosis and Gene Therapy of Immuno-Rejection in Rat Allogeneic Heart Transplantation Model Using a T-Cell-Targeted Theranostic Nanosystem

As the final life-saving treatment option for patients with terminal organ failure, organ transplantation is far from an ideal solution. The concomitant allograft rejection, which is hardly detectable especially in the early acute rejection (AR) period characterized by an intense cellular and humoral attack on donor tissue, greatly affects the graft survival and results in rapid graft loss. Based on a magnetic resonance imaging (MRI)-visible and T-cell-targeted multifunctional polymeric nanocarrier developed in our lab, effective co-delivery of pDNA and superparamagnetic iron oxide nanoparticles into primary T cells expressing CD3 molecular biomarker was confirmed in vitro. In the heart transplanted rat model, this multifunctional nanocarrier showed not only a high efficiency in detecting post-transplantation acute rejection but also a great ability to mediate gene transfection in T cells. Upon intravenous injection of this MRI-visible polyplex of nanocarrier and pDNA,T-cell gathering was detected at the endocardium of the transplanted heart as linear strongly hypointense areas on the MRI T-2*-weighted images on the third day after cardiac transplantation. Systematic histological and molecular biology studies demonstrated that the immune response in heart transplanted rats was significantly suppressed upon gene therapy using the polyplex bearing the DGK alpha gene. More excitingly, the therapeutic efficacy was readily monitored by noninvasive MRI during the treatment process. Our results revealed the great potential of the multifunctional nanocarrier as a highly effective imaging tool for real-time and noninvasive monitoring and a powerful nanomedicine platform for gene therapy of AR with high efficiency.

作为终末期器官衰竭患者的最终救命治疗选择，器官移植远非理想的解决方案。伴随的同种异体移植物排斥反应，尤其在以对供体组织的强烈细胞和体液攻击为特征的早期急性排斥反应（AR）阶段很难被检测到，这极大地影响了移植物的存活，并导致移植物迅速丧失功能。基于我们实验室开发的一种磁共振成像（MRI）可见且靶向T细胞的多功能聚合物纳米载体，在体外证实了能将质粒DNA和超顺磁性氧化铁纳米颗粒有效地共同递送至表达CD3分子生物标志物的原代T细胞中。在心脏移植大鼠模型中，这种多功能纳米载体不仅在检测移植后的急性排斥反应方面表现出高效率，而且在介导T细胞的基因转染方面也具有很强的能力。在静脉注射这种由纳米载体和质粒DNA组成的MRI可见的复合物后，在心脏移植后的第三天，在MRI T - 2*加权图像上，在移植心脏的心内膜处检测到T细胞聚集，表现为线性的低信号区域。系统的组织学和分子生物学研究表明，使用携带DGKα基因的复合物进行基因治疗后，心脏移植大鼠的免疫反应受到显著抑制。更令人兴奋的是，在治疗过程中可以通过无创MRI轻松监测治疗效果。我们的研究结果揭示了多功能纳米载体作为一种高效的实时无创监测成像工具以及一个高效的急性排斥反应基因治疗的强大纳米医学平台的巨大潜力。