Abstract
AIM: The GFAP was traditionally considered to be a biomarker for neural glia (mainly astrocytes and non-myelinating Schwann cells). Genetically, a 2.2-kb human GFAP promoter has been successfully used to target astrocytes in vitro and in vivo. More recently, GFAP was also established as one of the several makers for identifying hepatic stellate cells (HSC). In this project, possible application of the same 2.2-kb human GFAP promoter for targeting HSC was investigated. METHODS: The GFAP-lacZ transgene was transfected into various cell lines (HSC, hepatocyte, and other non-HSC cell types). The transgene expression specificity was determined by X-gal staining of the beta-galactosidase activity. And the responsiveness of the transgene was tested with a typical pro-fibrotic cytokine TGF-beta1. The expression of endogenous GFAP gene was assessed by real-time RT-PCR, providing a reference for the transgene expression. RESULTS: The results demonstrated for the first time that the 2.2 kb hGFAP promoter was not only capable of directing HSC-specific expression, but also responding to a known pro-fibrogenic cytokine TGF-beta1 by upregulation in a dose- and time-dependent manner, similar to the endogenous GFAP. CONCLUSION: In conclusion, these findings suggested novel utilities for using the GFAP promoter to specifically manipulate HSC for therapeutic purpose.