Pakyari Mohammadreza, Farokhi Ali, Jalili Reza B, Kilani Ruhangiz T, Brown Erin, Ghahary Aziz
BC Professional Firefighters' Burn and Wound Healing Research Laboratory, Department of Surgery, Plastic Surgery, University of British Columbia, Vancouver, Canada.
Division of Plastic Surgery, Department of Surgery, University of British Columbia, Vancouver, Canada.
Adv Wound Care (New Rochelle). 2019 Feb 1;8(2):58-70. doi: 10.1089/wound.2018.0811. Epub 2019 Feb 13.
Despite the effectiveness of skin autotransplantation, the high degree of immunogenicity of the skin precludes the use of allografts and systemic immunosuppression is generally inappropriate for isolated skin grafts. Indoleamine 2,3 dioxygenase (IDO) is a potent immunoregulatory factor with allo- and autoimmune suppression and tolerance induction properties. This study examines the potential use of locally expressed IDO to prolong the allogeneic skin graft take in a mouse model. Syngeneic-fibroblasts were transfected with noncompetent IDO viral vector and the level of Kynurenine (Kyn) in conditioned medium was measured as an index for IDO activity. Either 1 or 3 × 10 IDO-fibroblasts were introduced intra/hypo-dermally to the mouse skin. The expression, localization, and functionality of IDO were then evaluated. The cell-injected areas were harvested and grafted on the back of allogeneic mice. The graft survival, immune-cells infiltration, and interaction with dendritic cells were evaluated. The results showed a significant improvement in allogeneic graft take injected with 1 × 106 IDO-fibroblasts (18.4 ± 3.3 days) compared with control (12.2 ± 1.9 days). This duration increased to 35.4 ± 4.7 days in grafts injected with 3 × 10 IDO-expressing cells. This observation might be due to a significantly lower T cells infiltration within the IDO-grafts. Further, the result of a flow cytometric analysis showed that the expression of PD-L1/PD-L2 on CD11c+/eFluor+ cells in the regional lymph nodes of injected skin areas was significantly higher in IDO groups compared with control. These data suggest that allogeneic skin graft survival outcome can be prolonged significantly by local overexpression of IDO without any systemic effect.
尽管皮肤自体移植有效，但皮肤的高度免疫原性排除了同种异体移植的使用，并且全身免疫抑制通常不适用于孤立的皮肤移植。吲哚胺2,3-双加氧酶（IDO）是一种具有同种异体和自身免疫抑制以及诱导耐受性特性的强效免疫调节因子。本研究在小鼠模型中考察局部表达的IDO延长同种异体皮肤移植存活时间的潜在用途。用无活性的IDO病毒载体转染同基因成纤维细胞，并测量条件培养基中犬尿氨酸（Kyn）的水平作为IDO活性指标。将1×10⁶或3×10⁶个IDO-成纤维细胞皮下或皮内注射到小鼠皮肤中。然后评估IDO的表达、定位和功能。收获细胞注射区域并移植到同种异体小鼠的背部。评估移植物存活、免疫细胞浸润以及与树突状细胞的相互作用。结果显示，与对照组（12.2±1.9天）相比，注射1×10⁶个IDO-成纤维细胞（18.4±3.3天）的同种异体移植物存活时间有显著改善。在注射了3×10⁶个表达IDO细胞的移植物中，这个时间延长到了35.4±4.7天。这一观察结果可能是由于IDO移植物内T细胞浸润显著减少。此外，流式细胞术分析结果显示，与对照组相比，IDO组注射皮肤区域局部淋巴结中CD11c⁺/eFluor⁺细胞上PD-L1/PD-L2的表达显著更高。这些数据表明，通过局部过表达IDO可显著延长同种异体皮肤移植的存活时间，且无任何全身效应。
