N-Acetylglucosaminyltransferase V (GnT-V), catalyzing β1-6 branching in
asparagine-linked
oligosaccharides, is one of the most important
glycosyltransferases involved in
tumor metastasis and
carcinogenesis. Although the expression of GnT-V is induced in chronic
liver diseases, the
biological meaning of GnT-V in the diseases remains unknown. The aim of this study was to investigate the effects of GnT-V on the progression of
chronic hepatitis, using GnT-V transgenic (Tg) mice fed a high fat and high
cholesterol (HFHC) diet, an experimental model of murine
steatohepatitis. Although enhanced hepatic lymphocytes infiltration and
fibrosis were observed in wild-type (WT) mice fed the HFHC diet, they were dramatically prevented in Tg mice. In addition, the gene expression of inflammatory Th1
cytokines in the liver was significantly decreased in Tg mice than WT mice. Inhibition of
liver fibrosis was due to the dysfunction of hepatic stellate cells (HSCs), which play pivotal roles in
liver fibrosis through the production of
transforming growth factor (TGF)-β1. Although TGF-β1 signaling was enhanced in Tg mouse-derived HSCs (Tg-HSCs) compared with WT mouse-derived HSCs (WT-HSCs),
collagen expression was significantly reduced in Tg-HSCs. As a result from
DNA microarray,
cyclooxygenase-2 (COX2) expression, known as a negative feedback signal for TGF-β1, was significantly elevated in Tg-HSCs compared with WT-HSCs.
Prostaglandin E2 (
PGE2), the product of COX2, production was also significantly elevated in Tg-HSCs. COX2 inhibition by
celecoxib decreased
PGE2 and increased
collagen expression in Tg-HSCs. In conclusion, GnT-V prevented
steatohepatitis progression through modulating lymphocyte and HSC functions.