Hepatitis B virus-induced hFGL2 transcription is dependent on c-Ets-2 and MAPK signal pathway.
Fibrinogen-like protein 2 (FGL2)/fibroleukin plays a pivotal role in the pathogenesis of experimental and human fulminant and chronic viral hepatitis. To define the transcription factor(s) and upstream signal transduction pathways involved in the transcription of human FGL2 (hFGL2) in response to hepatitis B (HB) virus, hepatitis B core (HBc), hepatitis B virus S protein (HBs), or hepatitis B virus X protein (HBx) protein, expression plasmids were cotransfected with an hFGL2 promoter luciferase reporter construct into Chinese hamster ovary and HepG2 cells, respectively. HBc and HBx proteins, but not HBs protein, enhanced hFGL2 transcription in both cell lines. A strong regulatory region from -712 to -568 (relative to the transcriptional starting site) was shown to be responsible for hFGL2 gene transcription in response to both HBc and HBx proteins. c-Ets-2 was shown to be translocated to the nucleus in association with hFGL2 expression in response to both HBc and HBx proteins. Short hairpin RNA (shRNA) interference of c-Ets-2 expression inhibited hFGL2 gene transcription by 64.8 and 60.0% in response to HBc and HBx, respectively. c-Ets-2 protein was highly expressed in peripheral blood mononuclear cells from patients with severe chronic hepatitis B (CHB) in contrast to patients with mild CHB. Increased phosphorylation of ERK and JNK was detected in peripheral blood mononuclear cells from patients with severe CHB. ERK inhibitor PD098059 or ERK shRNA abolished the nuclear c-Ets-2 DNA binding activity and hFGL2 induction in response to HBc, whereas JNK inhibitor SP600125 or JNK shRNA abolished the nuclear c-Ets-2 DNA binding activity and hFGL2 induction in response to HBx. In conclusion, HBc and HBx proteins enhance transcription of hFGL2 through c-Ets-2 dependent on MAPK signal pathways.
Han
Meifang
M
Department of Infectious Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Yan
Weiming
W
Guo
Wei
W
Xi
Dong
D
Zhou
Yaoyong
Y
Li
Weina
W
Gao
Sui
S
Liu
Mingfeng
M
Levy
Gary
G
Luo
Xiaoping
X
Ning
Qin
Q
D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D016022:Case-Control Studies; D006224:Cricetinae; D003412:Cricetulus; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005340:Fibrinogen / Q000378:metabolism*; D006509:Hepatitis B / Q000378:metabolism; D006515:Hepatitis B virus / Q000378:metabolism*; D006801:Humans; D020935:MAP Kinase Signaling System; D008954:Models, Biological; D008969:Molecular Sequence Data; D021381:Protein Transport; D050787:Proto-Oncogene Protein c-ets-2 / Q000378:metabolism*; D014158:Transcription, Genetic
C494069:ETS2 protein, human; D004791:Enzyme Inhibitors; C095202:FGL2 protein, human; D050787:Proto-Oncogene Protein c-ets-2; D005340:Fibrinogen