Abstract
BACKGROUND: Interleukin (IL)-27 is a cytokine belonging to the IL-6/IL-12 cytokine family that is secreted by activated macrophages and dendritic cells and which strongly acts on T-cells and cells of the innate immune system. Not much is known about possible effects of IL-27 on other cell types. It signals via the common IL-6-type-cytokine receptor chain gp130 and the IL-27-specific chain WSX-1. We previously described that IL-27 also stimulates hepatoma cells and primary hepatocytes. The aim of this study was to investigate whether IL-27 would also act on hepatic stellate cells (HSC), the second most abundant hepatic cell type, which would demonstrate a more general role of this cytokine in the liver. RESULTS: Using a human HSC line and primary rat HSC we investigated the signalling characteristics of IL-27 in these cells. We show that IL-27 activates signal transducer and activator of transcription (STAT) 1 and to a minor extent STAT3 in a human HSC cell line and that it leads to the induction of STAT1 target genes such as interferon response factor-1, myxovirus resistance A and STAT1 itself. Similarly we find that IL-27 also elicits STAT1-dependent responses in primary rat HSC. CONCLUSIONS: We provide the first evidence for a function of IL-27 in HSC and show that its responses resemble Interferon-gamma-like functions in these cells. Our data suggests that IL-27 may play an important role in the context of liver inflammation by acting on the different liver cell types.