Fra-1 potentiates osteoclastic differentiation in osteoclast-macrophage precursor cell lines

✍ Scribed by J.M. Owens; K. Matsuo; G.C. Nicholson; E.F. Wagner; T.J. Chambers

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 351 KB
• Volume: 179
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/(sici)1097-4652(199905)179:2<170::aid-jcp7>3.0.co;2-k

✦ Synopsis

c-Fos, a component of the dimeric transcription factor AP-1, is necessary for osteoclast formation. To determine whether c-Fos can substitute for any or all of the stimuli needed for osteoclast induction, we infected osteoclast precursors with retroviral vectors expressing c-Fos or the Fos-related protein, Fra-1. The infected cells were incubated with or without osteoclast-inductive stimuli. Osteoclast formation from retroviral-infected precursors remained completely dependent on osteoclast-inductive stromal cells. Unexpectedly, infection of bipotential osteoclast-macrophage precursor cell lines with retroviruses expressing Fra-1 but not c-Fos caused a 10 -100-fold increase in the number of precursors that developed calcitonin receptors associated with an increase in bone resorption. These observations suggest that, in the precursor cell lines, Fra-1 is a limiting factor for full responsiveness to the osteoclast-inductive environment. Fra-1 is therefore likely to play a role in osteoclast differentiation which is distinct from that of c-Fos.