Chen Zhi, Li Yang-Xia, Fu Hai-Jing, Ren Yan-Li, Zou Ling, Shen Shi-Zhen, Chen Ping, Sun Ting, Huang Chun-Hong
Cell Physiol Biochem. 2017;41(1):91-100. doi: 10.1159/000455954. Epub 2017 Jan 17.
Hepatitis B virus (HBV) causes both acute and chronic liver injury. Viral proteins are involved in the pathological progress. Hepatitis B core antigen (HBcAg), a component of viral nucleocapsid, is not only essential for HBV lifecycle, but also exhibits strong immunogenicity. The cytoplasmic location of HBcAg in liver biopsy is associated with liver injury and inflammation, but the exact mechanisms remain to be elaborated.
Huh7, SMMC-7721 and L-02 cells were transfected with pEGFP-N1-HBcAg to establish an intracellular HBcAg expression model. The mRNA and protein levels of Interleukin (IL)-6 were detected by qPCR and ELISA respectively. The signaling pathway-related proteins were investigated by western blot and immunofluorescence assay.
HBcAg increased the expression and secretion of IL-6 through activating extracellular signal-related kinase (ERK), p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa B (NF-κB). These activations can be blocked by specific inhibitors of the three pathways.
HBcAg actives p38, ERK1/2 and NF-κB to enhance the production of IL-6 in hepatocytes. This provides a molecular mechanism to explain the association of cytoplasmic HBcAg with severe liver injury and inflammation.
乙型肝炎病毒（HBV）可导致急性和慢性肝损伤。病毒蛋白参与了其病理进程。乙型肝炎核心抗原（HBcAg）作为病毒核衣壳的一个组成部分，不仅对HBV生命周期至关重要，还具有很强的免疫原性。肝活检中HBcAg的胞质定位与肝损伤及炎症相关，但确切机制仍有待阐明。
将pEGFP-N1-HBcAg转染至Huh7、SMMC-7721和L-02细胞，以建立细胞内HBcAg表达模型。分别通过qPCR和ELISA检测白细胞介素（IL）-6的mRNA和蛋白水平。通过蛋白质印迹法和免疫荧光测定法研究信号通路相关蛋白。
HBcAg通过激活细胞外信号调节激酶（ERK）、p38丝裂原活化蛋白激酶（p38 MAPK）和核因子-κB（NF-κB）来增加IL-6的表达和分泌。这三种信号通路的特异性抑制剂可阻断这些激活作用。
HBcAg激活p38、ERK1/2和NF-κB，以增强肝细胞中IL-6的产生。这为解释胞质HBcAg与严重肝损伤及炎症之间的关联提供了一种分子机制。
