TY - JOUR
T1 - High mobility group box 1 activates toll like receptor 4 signaling in hepatic stellate cells
AU - Zhang, Zhe
AU - Lin, Chenzhao
AU - Peng, Lijun
AU - Ouyang, Yangyang
AU - Cao, Yirong
AU - Wang, Jiyao
AU - Friedman, Scott L.
AU - Guo, Jinsheng
N1 - Funding Information:
We gratefully thank Drs. Masayuki Fukata and Betty Schwartz for providing plasmids. This study was supported by the National Fund of Nature Science of P.R. China (No. 81070340 ) and the Open Project Program Foundation of Key Laboratory of Liver and Kidney Disease (Shanghai University of Traditional Chinese Medicine), Ministry of Education to JG.
PY - 2012/9/4
Y1 - 2012/9/4
N2 - Aims: The aim of the present study was to investigate the effect of high mobility group box 1 (HMGB1), a damage pattern molecule that signals the presence of necrosis, on TLR4 signaling in hepatic stellate cells (HSC). Main methods: Immortalized mouse HSC lines JS1, JS2, and JS3 that were either TLR4 +/+, TLR4 -/-, or MyD88 -/- were transfected with NF-κB or AP-1 responsive luciferase reporter plasmids, followed by stimulation with 100 ng/ml lipopolysacchride (the exogenous TLR4 ligand) or 100 ng/ml HMGB1. The activation of NF-κB or AP-1 activities was determined by a dual-luciferase reporter assay system. The cells were also stimulated with LPS or HMGB1 and collected for the determination of chemotactic cytokine MCP-1 mRNA or proteins secretion. In a separate experiment, the cells were co-stimulated with 10 μg/ml TGF-β1 and LPS or HMGB1 and collected for assessment of fibrogenic mRNA and protein expression. Key findings: HMGB1 stimulation markedly up-regulated MCP-1 mRNA expression and protein secretion, and enhanced TGF-β1-stimulated collagen α2(I) and α-SMA expression in JS1 cells. This was associated with enhanced activation of NF-κB and AP-1 responsive luciferase reporters. On the contrary, JS2 and JS3 cells were hyporesponsive to both LPS and HGMB1 stimulation compared to JS1 cells. Significance: As an endogenous ligand of TLR4, HMGB1 activates TLR4 signaling in HSCs to enhance their inflammatory phenotype, indicating that TLR4 signaling need not rely solely on gut-derived LPS for activation during liver injury. HMGB1 also has a synergistic effect with TGF-β1 to stimulate fibrogenic protein expression, which is likely to be TLR4 dependent.
AB - Aims: The aim of the present study was to investigate the effect of high mobility group box 1 (HMGB1), a damage pattern molecule that signals the presence of necrosis, on TLR4 signaling in hepatic stellate cells (HSC). Main methods: Immortalized mouse HSC lines JS1, JS2, and JS3 that were either TLR4 +/+, TLR4 -/-, or MyD88 -/- were transfected with NF-κB or AP-1 responsive luciferase reporter plasmids, followed by stimulation with 100 ng/ml lipopolysacchride (the exogenous TLR4 ligand) or 100 ng/ml HMGB1. The activation of NF-κB or AP-1 activities was determined by a dual-luciferase reporter assay system. The cells were also stimulated with LPS or HMGB1 and collected for the determination of chemotactic cytokine MCP-1 mRNA or proteins secretion. In a separate experiment, the cells were co-stimulated with 10 μg/ml TGF-β1 and LPS or HMGB1 and collected for assessment of fibrogenic mRNA and protein expression. Key findings: HMGB1 stimulation markedly up-regulated MCP-1 mRNA expression and protein secretion, and enhanced TGF-β1-stimulated collagen α2(I) and α-SMA expression in JS1 cells. This was associated with enhanced activation of NF-κB and AP-1 responsive luciferase reporters. On the contrary, JS2 and JS3 cells were hyporesponsive to both LPS and HGMB1 stimulation compared to JS1 cells. Significance: As an endogenous ligand of TLR4, HMGB1 activates TLR4 signaling in HSCs to enhance their inflammatory phenotype, indicating that TLR4 signaling need not rely solely on gut-derived LPS for activation during liver injury. HMGB1 also has a synergistic effect with TGF-β1 to stimulate fibrogenic protein expression, which is likely to be TLR4 dependent.
KW - Endogenous ligand
KW - Hepatic stellate cells
KW - High mobility group box-1
KW - Toll like receptor 4
UR - http://www.scopus.com/inward/record.url?scp=84865236513&partnerID=8YFLogxK
U2 - 10.1016/j.lfs.2012.07.009
DO - 10.1016/j.lfs.2012.07.009
M3 - Article
C2 - 22841886
AN - SCOPUS:84865236513
SN - 0024-3205
VL - 91
SP - 207
EP - 212
JO - Life Sciences
JF - Life Sciences
IS - 5-6
ER -