Stimulation of chondrogenesis in limb bud mesoderm cells by recombinant human bone morphogenetic protein 2B (BMP-2B) and modulation by transforming growth factor beta 1 and beta 2.
Bone morphogenetic protein 2B (BMP-2B) also called BMP-4 is one of a family of cartilage and bone-inductive proteins derived from bone matrix and belongs to the transforming growth factor beta (TGF-beta) superfamily. These bone-inductive proteins isolated from adult bone may be involved in bone repair. However, they may also play a role in cartilage and bone formation during embryonic development. To test whether BMP-2B influences cartilage formation by embryonic cells, recombinant human BMP-2B was applied to cultured limb bud mesoderm plated at three different densities. BMP-2B stimulated cartilage formation as assessed by Alcian blue staining and incorporation of radioactive sulfate into sulfated proteoglycans. Cells cultured at all three densities in the presence of 10 ng/ml BMP-2B formed a nearly continuous sheet of cartilage with abundant extracellular matrix and type II collagen. In addition, when cells were cultured in 0.5% serum in the presence of 10 ng/ml of BMP-2B for 5 days there was an increase in alkaline phosphatase as detected by histochemical and biochemical methods. Transforming growth factor beta isoforms (TGF-beta 1 and TGF-beta 2) inhibited sulfate incorporation into proteoglycans in a dose-dependent manner. This inhibition by TGF beta was overcome by recombinant BMP-2B. This study demonstrates that recombinant BMP-2B stimulates cartilage formation by chick limb bud mesoderm in vitro and is further modulated by TGF-beta isoforms.
Chen
P
P
Bone Cell Biology Section, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland 20892.
Carrington
J L
JL
Hammonds
R G
RG
Reddi
A H
AH
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D019485:Bone Morphogenetic Proteins; D002356:Cartilage / Q000166:cytology* / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D002642:Chick Embryo; D006133:Growth Substances / Q000494:pharmacology; D008648:Mesoderm / Q000166:cytology* / Q000187:drug effects; D011506:Proteins / Q000494:pharmacology*; D011509:Proteoglycans / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D019485:Bone Morphogenetic Proteins; D006133:Growth Substances; D011506:Proteins; D011509:Proteoglycans; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D000469:Alkaline Phosphatase; D013936:Thymidine