Membrane IL-1 induces bone resorption in organ culture.
We have studied the role of the membrane-associated form of IL-1 on bone resorption in vitro. Murine macrophages of the P388D1 cell line stimulated with LPS, subsequently fixed with paraformaldehyde, induced the proliferation of C3H/HeJ mouse thymocytes in the presence of a submitogenic concentration of Con A. Membrane IL-1 on P388D1 cells stimulated with LPS induced bone resorption in organ cultures of neonatal BALB/c mouse calvaria. Polyclonal antibodies directed against membrane IL-1 and soluble IL-1 from P388D1, and monospecific rabbit anti-murine rIL-1 alpha serum neutralized the membrane IL-1 activity, as measured by the thymocyte proliferation. In addition, these antibodies suppressed the bone resorption induced by membrane IL-1. The bone resorption induced by membrane IL-1 required direct contact between mouse calvaria and membrane IL-1. Salmon calcitonin strongly suppressed the calcium release from mouse calvaria in the presence of membrane IL-1. Indomethacin partially inhibited the bone resorption induced by membrane IL-1 on P388D1 cells. Moreover, membrane IL-1 on LPS-stimulated BALB/c mouse peritoneal macrophages or LPS-stimulated osteoblastic cells from BALB/c mouse calvaria induced bone resorption in vitro. These results suggest that membrane IL-1 on macrophages and osteoblastic cells may have a significant role in inflammatory bone resorption in vivo.
Nishihara
T
T
Department of Dental Research, National Institute of Health, Tokyo, Japan.
Ishihara
Y
Y
Noguchi
T
T
Koga
T
T
D000818:Animals; D001862:Bone Resorption / Q000187:drug effects; D002116:Calcitonin / Q000494:pharmacology; D002450:Cell Communication; D005404:Fixatives; D007106:Immune Sera / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000276:immunology / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000378:metabolism; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000276:immunology / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D009924:Organ Culture Techniques; D010006:Osteoblasts / Q000378:metabolism; D012886:Skull
D005404:Fixatives; D007106:Immune Sera; D007375:Interleukin-1; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D002116:Calcitonin; D007213:Indomethacin