Differential gene expression of CINC, NOS II, and ICAM-1 in endotoxemic liver cells by rG-CSF

We have recently demonstrated that recombinant granulocyte colony-stimulating factor (rG-CSF) modulates lipopolysaccharide (LPS)-induced Kupffer cell activation with subsequent reduction in hepatic leukocyte-endothelial cell interaction, thereby achieving protection against microcirculatory perfusion failure and hepatic dysfunction. To further clarify the underlying mechanisms, rG-CSF treated liver cells were tested for the LPS-induced gene expression of cytokine-induced neutrophil chemoattractant (CINC) and intercellular adhesion molecule-1 (ICAM-1) as potential chemotactic and leukocyte-recruiting factors and for the gene expression of inducible nitric oxide synthase (NOS II) as potential modulator of leukocyte adherence.

Using a collagenase, DNAse/pronase digestion technique, hepatic parenchymal and nonparenchymal cell fractions were obtained from livers of in vivo rG-CSF pretreated Sprague-Dawley rats 2 h after LPS exposure. mRNA transcripts were assessed using northern blot analysis.

In control livers only ICAM-1 mRNA was found constitutively expressed in hepatic nonparenchymal cells. rG-CSF per se did not affect NOS II, CINC, or ICAM-1 expression in hepatic liver cells, while LPS induced a marked expression of NOS II, CINC, and ICAM-1 in nonparenchymal cells and, to a lesser extent, in hepatocytes. Administration of rG-CSF prior to LPS exposure tended to increase NOS II, CINC, and ICAM-1 mRNA transcripts in hepatocytes. In nonparenchymal cells, however, NOS II and CINC were found reduced in rG-CSF pretreated animals upon LPS exposure.

The present data show a strikingly different cell type specific pattern of inflammatory response genes in rG-CSF-modulated hepatic endotoxemia. Reduced expression of NOS II, in particular of CINC, in the nonparenchymal cell fraction may contribute to the reduced leukocyte adherence and thus attenuation of cell-dependent tissue injury in rG-CSF pretreated endotoxemic animals.