Detection of the Na(+)-K(+)-ATPase alpha 3-isoform in multinucleated macrophages.
We previously reported that multinucleated macrophages express a high concentration of Na(+)-K(+)-ATPases that are concentrated on the nonadherent domain of their plasma membrane (A. Vignery, T. Niven-Fairchild, D. H. Ingbar, and M. Caplan. J. Histochem. Cytochem. 37: 1265-1271, 1989). We also showed that an increase in newly synthesized alpha-subunit occurred during cell culture and multinucleation. We now present evidence that macrophage multinucleation in vitro is accompanied by an increased accumulation of Na(+)-K(+)-ATPase alpha-subunit mRNA. Most interesting is the detection of significant amount of both alpha 1- and alpha 3-isoform mRNA and peptide in these cells by in situ hybridization, Northern and Western blot analyses. These qualitative and quantitative variations in Na(+)-K(+)-ATPase expression suggest that macrophage multinucleation is accompanied by a coordinated regulation of gene expression and that multinucleation confers a specific function to macrophages. Multinucleated macrophages offer a novel model system to investigate not only the specific function(s) of the alpha 3-isoform but also the role of the Na(+)-K(+)-ATPase in giant cells and osteoclasts.
Vignery
A
A
Department of Orthopedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut 06510.
Wang
F
F
Qian
H Y
HY
Benz
E J
EJ
Gilmore-Hebert
M
M
D000818:Animals; D015152:Blotting, Northern; D002467:Cell Nucleus / Q000648:ultrastructure*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008264:Macrophages / Q000201:enzymology* / Q000648:ultrastructure; D010529:Peritoneal Cavity / Q000166:cytology; D011650:Pulmonary Alveoli / Q000166:cytology; D012333:RNA, Messenger / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism*
D007527:Isoenzymes; D012333:RNA, Messenger; D000254:Sodium-Potassium-Exchanging ATPase