Oem J-K, Jackel-Cram C, Li Y-P, Kang H-N, Zhou Y, Babiuk L A, Liu Q
Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, Saskatoon, SK, Canada.
Arch Virol. 2008;153(2):293-301. doi: 10.1007/s00705-007-1103-1. Epub 2007 Dec 13.
Hepatitis C is a devastating disease worldwide. Proteins encoded by the etiologic agent, hepatitis C virus (HCV), are believed to play important roles in HCV-associated pathogenesis. However, the biological functions of the non-structural protein-2 (NS2) encoded by HCV are not well characterized. Here, we show that HCV NS2 protein activates CXCL-8 (interleukin-8, IL-8) transcription in HepG2 cells as measured by reverse transcription-polymerase chain reaction and IL-8 promoter-luciferase reporter assays. Furthermore, when the kappaB site on the IL-8 promoter was eliminated by mutagenesis or when intracellular NF-kappaB activity was suppressed by an inhibitor, NS2 did not activate the IL-8 promoter, suggesting a role of NF-kappaB in this process. These results prompted us to hypothesize that HCV NS2 might be able to activate NF-kappaB. This hypothesis was tested by determination of NF-kappaB-driven reporter gene expression and NF-kappaB p65 subunit subcellular localization after HCV NS2 expression. Indeed, NS2 could up-regulate NF-kappaB-driven luciferase activity and was associated with p65 nuclear localization. These results demonstrate that HCV NS2 up-regulates IL-8 transcription through NF-kappaB. This newly identified function increases our understanding of the role of HCV NS2 protein in virus-host interactions.
丙型肝炎在全球范围内是一种极具破坏性的疾病。据信，病原体丙型肝炎病毒（HCV）编码的蛋白质在HCV相关的发病机制中发挥着重要作用。然而，HCV编码的非结构蛋白2（NS2）的生物学功能尚未得到充分表征。在此，我们通过逆转录-聚合酶链反应和IL-8启动子-荧光素酶报告基因检测发现，HCV NS2蛋白可激活HepG2细胞中CXCL-8（白细胞介素-8，IL-8）的转录。此外，当通过诱变消除IL-8启动子上的κB位点或用抑制剂抑制细胞内NF-κB活性时，NS2不能激活IL-8启动子，这表明NF-κB在此过程中发挥了作用。这些结果促使我们推测HCV NS2可能能够激活NF-κB。通过检测HCV NS2表达后NF-κB驱动的报告基因表达和NF-κB p65亚基的亚细胞定位对这一推测进行了验证。事实上，NS2可上调NF-κB驱动的荧光素酶活性，并与p65的核定位相关。这些结果表明，HCV NS2通过NF-κB上调IL-8转录。这一新发现的功能增进了我们对HCV NS2蛋白在病毒-宿主相互作用中作用的理解。
