Expression of members of the thrombospondin family by human skeletal tissues and cultured cells.
We have previously shown that the multifunctional platelet glycoprotein thrombospondin-1 (TSP-1) promotes resorption in an in vitro resorption assay. However, TSP-1 is one of a family of multifunctional TSP molecules, and the current study was undertaken to investigate whether it is TSP-1 or another TSP family member which may be involved in regulation of resorption in vivo. RT-PCR was performed on cultured human bone cells, cultured human chondrocytes, and three separate samples of human osteoclastoma tissue using primers specific for each TSP family member. mRNA for TSP-2 was detected in almost all samples, and significantly in all osteoclastomas in the above tissues, while TSP-1 was detected less frequently and was only seen in one of three osteoclastomas. TSP-3, -4, and COMP were detected only in a minority of cases. These results indicate that TSP-2 is the most common TSP family member found in skeletal tissues and that TSP-2, rather than TSP-1, may be the molecule responsible for promoting resorption in vivo.
Carron
J A
JA
Department of Human Anatomy and Cell Biology, New Medical School, University of Liverpool, Ashton Street, Liverpool, L69 3GE, United Kingdom.
Bowler
W B
WB
Wagstaff
S C
SC
Gallagher
J A
JA
D001862:Bone Resorption / Q000378:metabolism*; D001842:Bone and Bones / Q000378:metabolism*; D064236:Cartilage Oligomeric Matrix Protein; D002478:Cells, Cultured; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis* / Q000235:genetics; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D064235:Matrilin Proteins; D020033:Protein Isoforms / Q000096:biosynthesis; D019700:Thrombospondin 1 / Q000096:biosynthesis / Q000235:genetics; D019699:Thrombospondins / Q000096:biosynthesis* / Q000235:genetics; D000099262:Thrombospondin 2
D064236:Cartilage Oligomeric Matrix Protein; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D064235:Matrilin Proteins; D020033:Protein Isoforms; D019700:Thrombospondin 1; D019699:Thrombospondins; D000099262:Thrombospondin 2; C577553:TSP5 protein, human; C101863:thrombospondin 3