Thrombin mediated migration of osteogenic cells.
Given that thrombin is ubiquitously expressed at sites of vascular injury, and that osteogenic cells express receptors for thrombin, we questioned whether thrombin could attract osteogenic cells to a bony wound. Using a scratch wound assay, thrombin stimulated a significant increase in migration of osteogenic cultures of primary marrow cells. This effect was dependent on thrombin proteolytic activity; however, thrombin was unable to stimulate the migration of a more differentiated marrow-derived osteogenic cell line. To better understand the role of thrombin in osteoprogenitor migration, we developed an osteoprogenitor migration assay that combines a modified Boyden chamber with a bone nodule assay. Primary cells that migrated through the transwell filter in the presence of thrombin formed significantly more bone nodules compared to the condition without thrombin. This was not due to proliferation or differentiation effects of thrombin. In contrast, thrombin was unable to stimulate an increase in the number of nodules for the more differentiated osteogenic cell line. Thus, our results suggest that thrombin exhibits differential motogenic effects on osteogenic cells depending on their differentiation state. The cell migration/bone nodule assay described here is the first assay that can be specifically used to examine the effects of factors on the migration of osteoprogenitor cells, particularly those derived from primary populations.
Karp
Jeffrey M
JM
Institute of Biomaterials and Biomedical Engineering, University of Toronto, 4 Taddle Creek Road, Toronto, Ontario, Canada. jeffkarp@MIT.EDU
Tanaka
Tetsuya S
TS
Zohar
Ron
R
Sodek
Jaro
J
Shoichet
Molly S
MS
Davies
John E
JE
Stanford
William L
WL
D000199:Actins / Q000378:metabolism; D000818:Animals; D001853:Bone Marrow / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects*; D010012:Osteogenesis / Q000187:drug effects; D051381:Rats; D044463:Receptor, PAR-1 / Q000235:genetics / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects
D000199:Actins; D044463:Receptor, PAR-1; D013917:Thrombin