J. Biol. Chem., Vol. 261, Issue 26, 12060-12065, Sep, 1986
Selective inhibition of collagen synthesis by the Ca2+ ionophore A23187 in cultured human fibroblasts
M Flaherty and M Chojkier
The question of whether the Ca2+ ionophore A23187 affects collagen
production relative to total protein synthesis or has possible effects on
collagen degradation was investigated. Cultured normal human fibroblasts
were incubated with radioactive proline, and the radioactivity of
collagenase-sensitive and -resistant proteins was used to calculate the
rates of protein production. The net production of collagen relative to
total proteins was inhibited by A23187 in a dose- related manner, and 50%
inhibition of basal collagen production was achieved with 0.6 microM
A23187. There was a 70% decrease in the absolute rate of collagen
production in the presence of 0.6 microM A23187 which represented a 4-fold
greater inhibition of collagen production than of noncollagen protein
production. The major mechanism for the decreased net production of
collagen was decreased synthesis, rather than increased degradation. Ca2+
mobilization induced by cholecystokinin octapeptide was also associated
with selective inhibition of collagen production in normal human
fibroblasts. These studies establish that the Ca2+ ionophore A23187 induces
a selective decrease in collagen polypeptide synthesis by normal human
fibroblasts and suggest a modulatory role of Ca2+ on collagen metabolism.