Epigallocatechin gallate and genistein attenuate glial fibrillary acidic protein elevation induced by fibrogenic cytokines in hepatic stellate cells.
Hepatic stellate cells (HSCs) play a pivotal role in hepatic fibrogenesis, and are considered a cellular target for therapeutic intervention. We recently established that a 2.2-kb hGFAP (human glial fibrillary acidic protein) promoter could be used to specifically target cultured HSCs. In the current study, we aimed to investigate whether the same transgene (2.2-kb hGFAP-lacZ) can be used as a biomarker for studying the inhibition of HSC activation. HSC-T6 cells stably transfected with the transgene were treated with two natural anti-fibrotic compounds, epigallocatechin gallate (EGCG) and genistein separately. Results showed that both transgenic beta-galactosidase activity and endogenous GFAP expression (mRNA and protein) were attenuated by EGCG or genistein treatment in a dose- and time-dependent manner. Our data further demonstrated that the suppression of fibrogenic end-points was primarily mediated through the inhibition of AP-1 signaling (and to a lesser degree through the NFkappaB pathway) onto the GFAP promoter. In conclusion, the current findings provide a proof-of-concept for using GFAP for studying HSC activation and inhibition. It could be envisioned that a HSC-based high-throughput system can be constructed using the GFAP promoter in conjunction with a real-time reporter for the screening of anti-fibrotic and anti-inflammatory agents.
Zhang
Chunyan
C
Institute of Bioengineering and Nanotechnology, 138669 Singapore.
Zhuo
Lang
L
D000818:Animals; D015153:Blotting, Western; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D002460:Cell Line; D016207:Cytokines / Q000145:classification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D024202:Electrophoretic Mobility Shift Assay; D019833:Genistein / Q000737:chemistry / Q000494:pharmacology*; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics / Q000378:metabolism*; D022781:Hepatocytes / Q000737:chemistry* / Q000187:drug effects*; D015394:Molecular Structure; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D013997:Time Factors; D014162:Transfection; D019076:Transgenes
D016207:Cytokines; D005904:Glial Fibrillary Acidic Protein; D012333:RNA, Messenger; D002392:Catechin; C045651:epigallocatechin gallate; D019833:Genistein