E-selectin expression in experimental models of inflammation in mice

Abstract

E-selectin (CD62E, formerly termed ELAM-1) is a cytokine-inducible adhesion molecule which mediates the binding of neutrophils, monocytes, and skin homing T-cells. The murine homologue of E-selectin has been cloned. A monoclonal antibody (21KC10) was used here to study immunohistochemically the expression and regulation of murine E-selectin in vitro and in vivo. As described for the human system, there was no staining of normal endothelium in skin and other tissues. LPS and tumour necrosis factor-alpha (TNF-alpha), but not interleukin-4 (IL-4) or interferon-gamma (IFN-gamma), induced a transient expression of E-selectin, both when injected in vivo and when added to endothelial cell lines in vitro. To analyse temporal expression of E-selectin under pathophysiological conditions in vivo, we chose two murine models of inflammation: allergic (ACD) and irritant contact dermatitis (ICD). Expression of E-selectin was found to be induced on vascular endothelium of post-capillary venules in both ACD and ICD. In ICD, maximal staining of endothelial cells occurred earlier than in ACD. Expression of E-selectin during ICD and ACD was then compared between strains of mice which differ with regard to the intensity of their inflammatory reaction. BALB/c mice, which in contrast to C57BI/6 mice show a denser infiltrate and prolonged influx of granulocyte and monocytes, revealed a more pronounced and more prolonged expression of E-selectin than C57BI/6 mice. This held true for both ACD and ICD, and in each case, peak expression of E-selectin was associated with the highest density of the leukocytic infiltrate. This study thus reveals regulatory mechanisms involved in the expression of murine E-selectin in vivo and in vitro. It also demonstrates a correlation between endothelial expression of E-selectin and the genetically determined intensity of the inflammatory response.