Expression of adhesion molecules relevant to leukocyte migration on the microvilli of liver peritoneal mesothelial cells.
To help assess the immunological functions of the liver peritoneum, expression and 3D-microlocalization of adhesion molecules were studied by immuno-SEM and -TEM. The peritoneal tissues of the liver obtained from lipopolysaccharide (LPS, 1.5 microg/g BW for 24 hr)-stimulated (n = 18 including nine controls) and non-stimulated mice (n = 6 including three controls) were analyzed by immunolabeling with 15 nm gold particle single-labeling analysis of ICAM-1, ICAM-2, VCAM-1, MAdCAM-1, PECAM-1, ELAM-1, and CD105 expression. In addition, 10 and 20 nm gold particle double-labeling analysis of ICAM-1 and VCAM-1 was carried out with conventional TEM and BSE (backscatter electron) imaging. Gold particles detected in the peritoneal mesothelial cells were quantified using a computer analyzer, LUZEX III. Only ICAM-1 in non-stimulated mice and both ICAM-1 and VCAM-1 in LPS-stimulated mice were expressed on the mesothelium, but no other adhesion molecules were detected in either condition. Expression of ICAM-1 was consistently about four times greater than that of VCAM-1. Each adhesion molecule was restricted to the microvilli. ICAM-1 was expressed on all microvilli and tended to form clusters of three or four molecules. On the other hand, about 24% of the microvilli expressed VCAM-1 and less clustering was seen. Double-labeling techniques disclosed that VCAM-1 and ICAM-1 were rarely closely associated, usually spaced by about 40 nm. These results suggest that microvilli of the mesothelial cell play a significant role in leukocyte migration in the peritoneal cavity, by providing the important substrates for adhesion, ICAM-1 and VCAM-1.
Liang
Y
Y
Department of Anatomy and Organ Technology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan. liangyan@sch.md.shinshu-u.ac.jp
Sasaki
K
K
D000818:Animals; D002465:Cell Movement / Q000502:physiology*; D004847:Epithelial Cells / Q000378:metabolism* / Q000648:ultrastructure; D004926:Escherichia coli / Q000276:immunology; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism* / Q000648:ultrastructure; D007962:Leukocytes / Q000502:physiology*; D008070:Lipopolysaccharides / Q000008:administration & dosage; D008099:Liver / Q000166:cytology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008855:Microscopy, Electron, Scanning; D016253:Microscopy, Immunoelectron; D008871:Microvilli / Q000648:ultrastructure; D010537:Peritoneum / Q000166:cytology; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism* / Q000648:ultrastructure
D008070:Lipopolysaccharides; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1