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Abstract：
OBJECTIVE: Hepatitis C virus (HCV) is a leading cause of chronic liver diseases and the most common indication for liver transplantation in the United States. HCV particles in the blood of infected patients are characterized by heterogeneous buoyant densities, likely owing to HCV association with lipoproteins. However, clinical isolates are not infectious in vitro and the relative infectivity of the particles with respect to their buoyant density therefore cannot be determined, pointing to the need for better in vivo model systems.
METHODS: To analyze the evolution of the buoyant density of in vivo-derived infectious HCV particles over time, we infected immunodeficient human liver chimeric fumaryl acetoacetate hydrolase-/- mice with J6/JFH1 and performed ultracentrifugation of infectious mouse sera on isopicnic iodixanol gradients. We also evaluated the impact of a high sucrose diet, which has been shown to increase very-low-density lipoprotein secretion by the liver in rodents, on lipoprotein and HCV particle characteristics.
RESULTS: Similar to the severe combined immunodeficiency disease/Albumin-urokinase plasminogen activator human liver chimeric mouse model, density fractionation of infectious mouse serum showed higher infectivity in the low-density fractions early after infection. However, over the course of the infection, viral particle heterogeneity increased and the overall in vitro infectivity diminished without loss of the human liver graft over time. In mice provided with a sucrose-rich diet we observed a minor shift in HCV infectivity toward lower density that correlated with a redistribution of triglycerides and cholesterol among lipoproteins.
CONCLUSIONS: Our work indicates that the heterogeneity in buoyant density of infectious HCV particles evolves over the course of infection and can be influenced by diet.
METHODS: To analyze the evolution of the buoyant density of in vivo-derived infectious HCV particles over time, we infected immunodeficient human liver chimeric fumaryl acetoacetate hydrolase-/- mice with J6/JFH1 and performed ultracentrifugation of infectious mouse sera on isopicnic iodixanol gradients. We also evaluated the impact of a high sucrose diet, which has been shown to increase very-low-density lipoprotein secretion by the liver in rodents, on lipoprotein and HCV particle characteristics.
RESULTS: Similar to the severe combined immunodeficiency disease/Albumin-urokinase plasminogen activator human liver chimeric mouse model, density fractionation of infectious mouse serum showed higher infectivity in the low-density fractions early after infection. However, over the course of the infection, viral particle heterogeneity increased and the overall in vitro infectivity diminished without loss of the human liver graft over time. In mice provided with a sucrose-rich diet we observed a minor shift in HCV infectivity toward lower density that correlated with a redistribution of triglycerides and cholesterol among lipoproteins.
CONCLUSIONS: Our work indicates that the heterogeneity in buoyant density of infectious HCV particles evolves over the course of infection and can be influenced by diet.
摘要：
目的：丙型肝炎病毒（HCV）是导致慢性肝病的主要原因，也是美国肝移植最常见的适应症。感染患者血液中的HCV颗粒的特征是不均匀的浮力密度，可能是由于HCV与脂蛋白相关。然而,临床分离株在体外不具有传染性，因此无法确定颗粒相对于其浮力密度的相对感染性，指出需要更好的体内模型系统。
方法：为了分析体内感染性HCV颗粒的浮力密度随时间的演变，我们用J6/JFH1感染了免疫缺陷的人肝脏嵌合富马酰基乙酰乙酸酯-/-小鼠，并在异族碘克沙醇梯度上对感染性小鼠血清进行了超速离心。我们还评估了高蔗糖饮食的影响，已被证明可以增加啮齿动物肝脏的极低密度脂蛋白分泌，脂蛋白和HCV颗粒特征。
结果：类似于严重联合免疫缺陷病/白蛋白-尿激酶型纤溶酶原激活剂人肝嵌合小鼠模型，感染小鼠血清的密度分级在感染后早期的低密度级分中显示出更高的感染性。然而,在感染过程中，随着时间的推移，病毒颗粒异质性增加，整体体外感染性降低，而没有人肝移植物的损失。在提供富含蔗糖的饮食的小鼠中，我们观察到HCV感染性向低密度的微小变化，这与脂蛋白中甘油三酯和胆固醇的重新分布有关。
结论：我们的工作表明，感染性HCV颗粒的浮力密度的异质性在感染过程中会发生变化，并且可能受到饮食的影响。
方法：为了分析体内感染性HCV颗粒的浮力密度随时间的演变，我们用J6/JFH1感染了免疫缺陷的人肝脏嵌合富马酰基乙酰乙酸酯-/-小鼠，并在异族碘克沙醇梯度上对感染性小鼠血清进行了超速离心。我们还评估了高蔗糖饮食的影响，已被证明可以增加啮齿动物肝脏的极低密度脂蛋白分泌，脂蛋白和HCV颗粒特征。
结果：类似于严重联合免疫缺陷病/白蛋白-尿激酶型纤溶酶原激活剂人肝嵌合小鼠模型，感染小鼠血清的密度分级在感染后早期的低密度级分中显示出更高的感染性。然而,在感染过程中，随着时间的推移，病毒颗粒异质性增加，整体体外感染性降低，而没有人肝移植物的损失。在提供富含蔗糖的饮食的小鼠中，我们观察到HCV感染性向低密度的微小变化，这与脂蛋白中甘油三酯和胆固醇的重新分布有关。
结论：我们的工作表明，感染性HCV颗粒的浮力密度的异质性在感染过程中会发生变化，并且可能受到饮食的影响。
