Modulation of 1alpha,25-dihydroxyvitamin D3-membrane associated, rapid response steroid binding protein expression in mouse odontoblasts by 1alpha,25-(OH)2D3.
The rapid, nongenomic effects of 1alpha,25-dihydroxyvitamin D3 (1alpha,25-(OH)2D3 have been related to a 1,25D3-membrane associated, rapid response steroid binding protein or 1,25D3-[MARRS]bp, with a molecular weight of 65 kDa, in several tissues and species. Currently, no information is available concerning the nongenomic responses to 1alpha,25-(OH)2D3 in dental tissues. In order to investigate the expression of 1,25D3-[MARRS]bp in dental cells, in the presence or absence of 1alpha,25-(OH)2D3, we have used rabbit polyclonal antibodies directed against the N-terminus of the 1,25D3-[MARRS]bp (Ab099) that recognizes the 1alpha,25-(OH)2D3 binding protein in chick intestinal basolateral membranes and a mouse odontoblast-like cell line (MO6-G3). Western blotting and flow cytometric analyses with Ab099 specifically detected 1,25D3-[MARRS]bp in MO6-G3 cells. Moreover, 1,25D3-[MARRS]bp was up-regulated, in vivo, in differentiated dental cells. Electron microscopic analysis confirmed the plasma membrane localization of this binding protein and also showed its intracellular presence. Incubation of MO6-G3 cells with different doses of 1alpha,25-(OH)2D3 for 36 h resulted in an inhibition of 1,25D3-[MARRS]bp expression with a maximal effect at 50 nM steroid. In addition, the culture media of MO6-G3 cells contains immunoreactive 1,25D3-[MARRS]bp. Immunogold positive membrane vesicle-like structures are present in the extracellular matrix of MO6-G3 cells. Altogether, these results indicate that the 1,25D3-[MARRS]bp expression in MO6-G3 cells is modulated by 1alpha,25-(OH)2D3. In conclusion, this 1alpha,25-(OH)2D3 binding protein could play an important role in the rapid, nongenomic responses to 1alpha,25-(OH)2D3 in dental cells.
Teillaud
Christophe
C
Laboratoire de Biologie-Oro-Faciale et Pathologie, INSERM EMI-U 0110-IFR 58, Université Paris 7, Centre de Recherches Biomédicales des Cordeliers, Escalier E, Paris Cedex 06, France. teillaudchristophe@yahoo.fr
Nemere
Ilka
I
Boukhobza
Florine
F
Mathiot
Claire
C
Conan
Nicole
N
Oboeuf
Martine
M
Hotton
Dominique
D
Macdougall
Mary
M
Berdal
Ariane
A
D000818:Animals; D015153:Blotting, Western; D002117:Calcitriol / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008854:Microscopy, Electron; D008970:Molecular Weight; D009804:Odontoblasts / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure
D008565:Membrane Proteins; D002117:Calcitriol