Department of Clinical Sciences, North Carolina State University, Raleigh, NC 27607, USA; Bedrock Therapeutics, Raleigh, NC 27613, USA.
Department of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA; Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Mol Ther. 2024 Nov 6;32(11):4006-4020. doi: 10.1016/j.ymthe.2024.09.007. Epub 2024 Sep 7.
Corneal blindness affects more than 5 million individuals, with over 180,000 corneal transplantations (CTs) performed annually. In high-risk CTs, almost all grafts are rejected within 10 years. Here, we investigated adeno-associated virus (AAV) ex vivo gene therapy to establish immune tolerance in the corneal allograft to prevent high-risk CT rejection. Our previous work has demonstrated that HLA-G contributes to ocular immune privilege by inhibiting both immune cells and neovascularization; however, homodimerization is a rate-limiting step for optimal HLA-G function. Therefore, a chimeric protein called single-chain immunomodulator (scIM), was engineered to mimic the native activity of the secreted HLA-G dimer complex and eliminate the need for homodimerization. In a murine corneal burn model, AAV8-scIM significantly reduced corneal vascularization and fibrosis. Next, ex vivo AAV8-scIM gene delivery to corneal allografts was evaluated in a high-risk CT rejection rabbit model. All scIM-treated corneas were well tolerated and transparent after 42 days, while 83% of vehicle-treated corneas were rejected. Histologically, AAV-scIM-treated corneas were devoid of immune cell infiltration and vascularization, with minimal fibrosis at the host-graft interface. The data collectively demonstrate that scIM gene therapy prevents corneal neovascularization, reduces trauma-induced corneal fibrosis, and prevents allogeneic CT rejection in a high-risk large animal model.
角膜盲影响超过 500 万人，每年进行超过 18 万例角膜移植（CT）。在高风险 CT 中，几乎所有移植物在 10 年内都会被排斥。在这里，我们研究了腺相关病毒（AAV）离体基因治疗，以建立角膜同种异体移植物中的免疫耐受，从而防止高风险 CT 排斥。我们之前的工作表明，HLA-G 通过抑制免疫细胞和新生血管形成来促进眼部免疫特权；然而，同源二聚化是 HLA-G 发挥最佳功能的限速步骤。因此，设计了一种称为单链免疫调节剂（scIM）的嵌合蛋白，以模拟分泌的 HLA-G 二聚体复合物的天然活性并消除同源二聚化的需要。在小鼠角膜烧伤模型中，AAV8-scIM 显著减少了角膜血管化和纤维化。接下来，在高风险 CT 排斥兔模型中评估了离体 AAV8-scIM 基因传递对角膜同种异体移植物的影响。所有 scIM 治疗的角膜在 42 天后均耐受良好且透明，而 83%的载体治疗的角膜被排斥。组织学上，AAV-scIM 治疗的角膜没有免疫细胞浸润和血管化，在宿主-移植物界面仅有最小的纤维化。这些数据共同表明，scIM 基因治疗可预防角膜新生血管形成，减少创伤引起的角膜纤维化，并防止高风险大动物模型中的同种异体 CT 排斥。
