ABSTRACT: S100A4 is a member of the S100 calcium-binding protein family. S100A4 is expressed in several tissues; however, it is secreted by few cell types and its extracellular roles are unknown. In the present study we showed byin situhybridization that periodontal ligament (PDL) cells express the S100A4 mRNA. Immunolocalization of the S100A4 protein in cryosections of PDL and analyses of PDL cell culture medium revealed that PDL cells secrete the S100A4 protein bothin vivoandin vitro.Interestingly, addition of a recombinant mouse S100A4 protein to a bone marrow cell culture inhibited mineralized nodule formation in a concentration-dependent manner. This is the first report of an extracellular role for S100A4 as an inhibitor of mineralization. The PDL space is kept free of mineralization and S100A4 may be one of the factors responsible for such phenomenon.
Biochemical and Biophysical Research Communications 03/1999; · 2.48 Impact Factor