Division of Infectious Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
Transplantation. 2010 Apr 15;89(7):811-5. doi: 10.1097/TP.0b013e3181cbac18.
Hepatitis C virus (HCV) core and nonstructural (NS) 3 proteins induce inflammation and immunity through a toll-like receptor (TLR) 2-dependent pathway. Individuals with the R753Q single-nucleotide polymorphism (SNP) in the TLR2 gene have increased the risk of allograft failure after liver transplantation for chronic hepatitis C.
To test the hypothesis that R753Q SNP impairs TLR2 recognition of HCV proteins, a series of in vitro experiments were performed wherein stable clones of wild-type TLR2-deficient human embryonic kidney (HEK) 293 cells and HEK293 cells transfected with wild-type (HEK293-TLR2) or variant TLR2 genes (HEK293-TLR2-R753Q) were stimulated with HCV core and NS3 proteins. Cellular activation was assessed by nuclear factor-kappa B-driven luciferase activity, cytokine secretion, and gene upregulation.
Compared with TLR2-deficient HEK293 cells, HEK293-TLR2 cells had marked nuclear factor-kappa B-driven luciferase activity, had modest to marked upregulation in TLR2 signaling-associated genes, and secreted large quantities of interleukin-8 during exposure to HCV core and NS3 proteins. In contrast, HEK293-TLR2-R753Q cells did not respond to stimulation with HCV and behaved similarly like TLR2-deficient HEK293 cells.
R753Q SNP impairs TLR2-mediated immune recognition of HCV core and NS3 proteins. This biologic defect may account for the predisposition of patients to develop allograft failure after liver transplantation for chronic hepatitis C.
丙型肝炎病毒（HCV）核心和非结构（NS）3 蛋白通过 Toll 样受体（TLR）2 依赖性途径诱导炎症和免疫反应。TLR2 基因中 R753Q 单核苷酸多态性（SNP）的个体在慢性丙型肝炎肝移植后增加了同种异体移植物失功的风险。
为了验证 R753Q SNP 损害 TLR2 对 HCV 蛋白识别的假设，进行了一系列体外实验，其中稳定克隆的野生型 TLR2 缺陷型人胚肾（HEK）293 细胞和转染野生型（HEK293-TLR2）或变体 TLR2 基因（HEK293-TLR2-R753Q）的 HEK293 细胞用 HCV 核心和 NS3 蛋白刺激。通过核因子-κB 驱动的荧光素酶活性、细胞因子分泌和基因上调来评估细胞激活。
与 TLR2 缺陷型 HEK293 细胞相比，HEK293-TLR2 细胞具有明显的核因子-κB 驱动的荧光素酶活性，TLR2 信号相关基因有适度至明显的上调，并且在暴露于 HCV 核心和 NS3 蛋白时大量分泌白细胞介素-8。相比之下，HEK293-TLR2-R753Q 细胞对 HCV 的刺激没有反应，并且行为类似于 TLR2 缺陷型 HEK293 细胞。
R753Q SNP 损害了 TLR2 介导的 HCV 核心和 NS3 蛋白的免疫识别。这种生物学缺陷可能解释了慢性丙型肝炎肝移植后患者发生同种异体移植物失功的易感性。
