Uneven modulation of the annexin 1 system in osteoblast-like cells by dexamethasone.
We tested whether glucocorticoids modulated osteoblast expression of the annexin 1 system, including the ligand and two G-coupled receptors termed formyl-peptide receptor (FPR) and FPR-like-1 (FPRL-1). In Saos-2 cells, rapid up-regulation of FPR mRNA upon cell incubation with dexamethasone (0.01-1 microM) was observed, with significant changes as early as 2h and a more marked response at 24h; annexin 1 and FPRL-1 mRNA changes were more subtle. At the protein level, dexamethasone provoked a rapid externalization of annexin 1 (maximal at 2h) followed by delayed time-dependent changes in the cell cytosol. Saos-2 cell surface expression of FPR or FPRL-1 could not be detected, even when dexamethasone was added with the bone modelling cytokines interleukin-6 or interleukin-1. The uneven modulation of the annexin 1 system (mediator and its putative receptors) in osteoblasts might lead to a better understanding of how these complex biochemical pathways become operative in bone.
Giner
Rosa M
RM
Departmento de Farmacologia, Universitat de Valéncia, València, Spain.
Mancini
Lucia
L
Kamal
Ahmad M
AM
Perretti
Mauro
M
D017305:Annexin A1 / Q000096:biosynthesis / Q000378:metabolism*; D045744:Cell Line, Tumor; D003907:Dexamethasone / Q000494:pharmacology*; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism*; D044042:Receptors, Formyl Peptide / Q000096:biosynthesis / Q000235:genetics; D044067:Receptors, Lipoxin / Q000096:biosynthesis / Q000235:genetics
D017305:Annexin A1; C105101:FPR2 protein, human; D005938:Glucocorticoids; D044042:Receptors, Formyl Peptide; D044067:Receptors, Lipoxin; D003907:Dexamethasone