AJP - Renal Physiology, Vol 263, Issue 2 277-F283, Copyright © 1992 by American Physiological Society
Expression of vacuolar H(+)-ATPase in mouse osteoclasts during in vitro differentiation
Z. Q. Wang, P. Hemken, D. Menton and S. Gluck
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
Osteoclasts express high levels of a vacuolar H(+)-adenosinetriphosphatase
(H(+)-ATPase) on the ruffled membrane which they employ to dissolve bone
mineral by acidifying their site of attachment on bone. The factors that
control amplification of H(+)-ATPase during osteoclast differentiation are
poorly understood. We examined the expression of vacuolar H(+)-ATPase in a
cell culture system in which mouse spleen cells can be induced to
differentiate into osteoclasts by coculture with a mouse bone marrow
stromal cell line. We found that the coculture system produced active
osteoclasts, identified as multinucleated cells with staining for
tartrate-resistant acid phosphatase activity that formed genuine resorption
pits in bone. These cells developed high levels of H(+)-ATPase expression
in culture, and omission of dexamethasone or 1 alpha,25-dihydroxyvitamin D3
from the coculture system each partially suppressed the expression of
H(+)-ATPase. The results demonstrate that the spleen and PA6 cell coculture
system may be useful for investigating the factors that control the
induction of H(+)-ATPase amplification that occurs during osteoclast
differentiation.
