The role of transforming growth factor-beta on retarded osteoblastic differentiation in vitro.

Various matrix growth factors play important roles in the development and growth of cartilage and bone. Among them transforming growth factor-beta superfamily and especially bone morphogenetic proteins are known to be important factors, since they induce bone and cartilage formation in ectopic sites in vivo. We have previously shown that the human osteosarcoma cell line Saos-2 expresses molecules that in vivo induce new bone formation with asymmetric bone maturation.

Use of myoblasts in assaying the osteoinductivity of bone morphogenetic proteins.

A novel, time- and BMP-saving in vitro method for the detection and quantitation of bone morphogenetic protein (BMP) activity was developed based on the measurable effects of BMP on rat skeletal muscle myoblasts (L6). Calcium incorporation, stimulation of alkaline phosphatase activity and production of osteocalcin were used as markers of bone cell metabolism and on-going morphogenesis. The morphological change was confirmed by Chlorantine fast red and von Kossa staining.

Measurement of total and local bone morphogenetic protein concentration in bone tumours.

Bone morphogenetic protein (BMP) has been shown to be one of the significant factors in the prognosis of bone tumours. In normal development BMP induces new bone formation and later takes part in fracture healing, but its function in malignant tumours is not known. In this study the concentration of bone morphogenetic protein was measured in primary bone tumours by two methods.

Internalization and intracellular processing of bone morphogenetic protein (BMP) in rat skeletal muscle myoblasts (L6).

Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-beta (TGF-beta) superfamily capable of inducing bone and cartilage formation in ectopic extraskeletal sites and transducing their effects through binding to serine-threonine kinase receptors. In this study, the fate of 125I-labelled native BMP after binding to cell surface receptors on L6-myoblasts was examined with both continuous and intermittent exposure of the ligand. BMP was readily internalized in L6 cells at +37 degrees C, and the internalization reached a plateau in 2 h.

Partially purified reindeer (Rangifer tarandus) bone morphogenetic protein has a high bone-forming activity compared with some other artiodactyls.

Noncollagenous proteins, including bone morphogenetic protein (BMP), were extracted in 4 mol/l guanidinium hydrochloride (GuHCl) from the pulverized and HCl-demineralized matrix of reindeer, bovine, sheep and porcine bone. To remove water-soluble material, the GuHCl solution was dialyzed against water and water-insoluble material and redissolved in 4 mol/l GuHCl. Gelatin peptides were removed by extraction in 0.