Involvement of adhesion molecule in in vitro plaque-like formation of macrophages stimulated with Aggregatibacter actinomycetemcomitans lipopolysaccharide.
OBJECTIVE
Inflammatory agents, such as lipopolysaccharide (LPS), in periodontal pockets may promote atherogenesis by activating leukocytes. In our previous study, we developed a microchannel chip to observe the cell adhesion process in a fluid system. The objective of this investigation was to examine the mechanism by which periodontopathic bacterial LPS enhances plaque-like formation on a microchannel chip.


METHODS
To evaluate the effect of Aggregatibacter actinomycetemcomitans LPS on the expression of adhesion molecules, e.g. intercellular adhesion molecule 1 (ICAM-1), lymphocyte function-associated antigen 1 (LFA-1) and L-selectin, on the surface of murine macrophage RAW264.7 cells, the expression of each adhesion molecule was examined by flow cytometry and western blot analysis. Moreover, a flow test on the microchannel chip involving anti-adhesion molecule antibodies was conducted to clarify which adhesion molecule is related to plaque-like formation of RAW264.7 cells.


RESULTS
The expressions of ICAM-1 and LFA-1 on the surface of RAW 264.7 cells increased following 12 h culture with LPS; L-selectin expression was unaffected. An increase in ICAM-1 expression was also confirmed by western blot analysis. The flow test revealed that anti-ICAM-1 antibody inhibited plaque-like formation of LPS-stimulated macrophages on the micropillars of the microchannel chip.


CONCLUSIONS
These findings indicate that ICAM-1 plays an important role in plaque-like formation of LPS-stimulated macrophages. Our microchannel chip is a suitable tool for the investigation of etiological factors of atherosclerosis, including periodontitis, in vitro.
Tsutsumi
T
T
Division of Periodontology, Department of Cardiology and Periodontology, Kyushu Dental College, Kitakyushu, Japan.
Takeshi
T
T
Nakashima
K
K
Keisuke
N
N
Isoda
T
T
Takaaki
I
I
Yokota
M
M
Makoto
Y
Y
Nishihara
T
T
Tatsuji
N
N
D016976:Aggregatibacter actinomycetemcomitans / Q000502:physiology*; D000818:Animals; D000906:Antibodies; D050197:Atherosclerosis / Q000473:pathology; D015153:Blotting, Western; D002448:Cell Adhesion / Q000187:drug effects; D002449:Cell Aggregation / Q000187:drug effects; D018929:Cell Culture Techniques; D002460:Cell Line; D005434:Flow Cytometry; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis / Q000187:drug effects*; D019041:L-Selectin / Q000032:analysis / Q000187:drug effects*; D056656:Lab-On-A-Chip Devices; D008070:Lipopolysaccharides / Q000494:pharmacology*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000032:analysis / Q000187:drug effects*; D008264:Macrophages / Q000187:drug effects*; D051379:Mice
D000906:Antibodies; D008070:Lipopolysaccharides; D016169:Lymphocyte Function-Associated Antigen-1; D018799:Intercellular Adhesion Molecule-1; D019041:L-Selectin