Differential expression and regulation of chemokines JE, KC, and IP-10 gene in primary cultured murine hepatocytes

Chemokines are a superfamily of structurally related chemoattractant cytoki nes. IE (monocyte chemoattractant protein-1:) and IP-10 (interferon-inducib le protein-10) have been detected in the diseased liver. However the in Vit ro expression is unclear. In this report we revealed that JE, KC (melanoma growth-stimulating activity gene), and IP-10 mRNAs are not expressed in the normal liver but spontaneously and time-dependently expressed in the prima ry hepatocytes. The serum-independent gene expression of both JE and KC las ted over 72 h, but that of IP-10 became undetectable 24 h after isolation w ith collagenase perfusion method. The induction of the genes' expression wa s not due to LPS contamination but nevertheless was associated with isolati on procedure. Actinomycin D blocked their expression. The increase of their transcripts resulted from greater increase in gene transcription and lower mRNA stability. Consistent with c-jun, their mRNA expressions were simulta neously superinduced by cycloheximide (1 mu g/ml), suggesting that de novo protein synthesis is involved their transcriptions. Inhibition by pyrrolidi ne dithiocarbamate (PDTC), a NF-kappa B/c-rel inhibitor, and EMSA imply tha t NF-kappa B/c-rel is important in their expressions. Of particular interes t is that dexamethasone upregulated the spontaneous expression of KC, but s uppressed that of JE and IP-10. LPS upregulated the m RNA levels of JE and KC but did not affect that of IP-10. IFN-gamma induced the expression of IP -10; however unlike in macrophages, it did not selectively inhibit that of JE and KC. Our data demonstrated the existence and differential gene expres sion of JE, KC, and IP-10 in primary cultured hepatocytes, and these are co nsidered to be a reflex of the alteration of hepatocyte cellular physiology during and after isolation. (C) 1999 Wiley-Liss, Inc.