[Localization of the connexin 43 gap-junction protein in silica-exposed alveolar epithelial cells].
OBJECTIVE
To study the effect of supernatants from silicon dioxide(SiO2) stimulated pulmonary alveolar macrophages(PAM) on the localization of connexin 43(Cx43) so as to explore the inhibition level of SiO2 on alveolar epithelial cellular gap-junctional communication(GJIC).


METHODS
The supermatants from the primary cultured PAM were prepared, and then added 5% (v/v) SiO2 into 2% (v/v) NBS RPMI 1640 to stimulate the normal mink lung epithelial cell line CCL-64 for 24 hours. The localizations of Cx43 in CCL-64 were analyzed by indirect immunofluorescence histochemistry and laser confocal scanning microscopy(LCSM).


RESULTS
The normal cultured CCL-64 cells displayed bright membrane-associated Cx43 plaques labeling and formed dashes at regions of intercellular junction. Being exposed to supernatants from SiO2-stimulated PAM, the CCL-64 cells retained a relative low degree of Cx43 labeling at the cell periphery, localized in cytoplasm, and the individual spot, rather than plaques, were smaller compared to normal cultured cells. Along with the increase of the concentrations of SiO2, the cells displayed a different staining pattern, with clear cluster labeling aggregating towards the nucleus.


CONCLUSIONS
The altered localization of the gap-junctional protein Cx43 in alveolar epithelial cells, mediated by SiO2, indicated that the internalization of Cx43 may contribute to the inhibition on GJIC in silica-induced lung epithelium injury.
Mao
Guogen
G
Institute of Industrial and Environmental Hygiene, Zhejiang University, School of Medicine, Hangzhou 310031, China.
Ye
Shaojing
S
Zeng
Qunli
Q
D000818:Animals; D002450:Cell Communication / Q000187:drug effects; D002460:Cell Line; D018031:Connexin 43 / Q000032:analysis*; D004847:Epithelial Cells / Q000737:chemistry / Q000187:drug effects; D019084:Fluorescent Antibody Technique, Indirect; D017629:Gap Junctions / Q000187:drug effects; D018613:Microscopy, Confocal; D008907:Mink; D011650:Pulmonary Alveoli / Q000737:chemistry / Q000187:drug effects*; D012822:Silicon Dioxide / Q000633:toxicity*
D018031:Connexin 43; D012822:Silicon Dioxide