title: Microvascular pericytes express aggrecan message which is regulated by BMP-2.
abstract: Multipotential mesenchymal stem cells capable of chondro-osseous induction contribute to the endochondral callus of healing fractured bone. Microvascular pericytes serving the role of multipotential mesenchymal stem cells are considered osteoprogenitors because they express type I collagen, alkaline phosphatase enzyme activity, osteocalcin immunoreactivity, and bone sialoprotein mRNA. Previous electron microscopic studies indicate that this cell type has a contribution to the fracture callus. Limited data suggest that pericytes may also assume a chondrogenic phenotype. We undertook in vitro studies to understand how the chondro-osseous phenotype of the pericyte might be regulated. Using Northern analysis and semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), we found that cultured pericytes produce aggrecan and type II collagen mRNA indicating their chondrogenic potential. Aggrecan message is elevated by BMP-2 as analyzed by both Northern hybridization and RT-PCR. This finding suggests a regulatory role for this morphogen on this phenotype in pericytes. RT-PCR amplified versican product was also associated with pericyte cultures but was not affected by BMP-2. Our data strongly support a chondrogenic role for the pericyte and that the phenotype is regulated at least in part by BMP.
authors.affiliation: McKay Laboratories for Orthopaedic Surgery Research, Department of Orthopaedic Surgery, School of Medicine, University of Pennsylvania, 36th and Hamilton Walk, Philadelphia, Pennsylvania 19104-6081, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Diefenderfer
authors.forename: C T
authors.initials: CT
authors.lastname: Brighton
mesh_terms: D053674:Aggrecans; D000818:Animals; D001483:Base Sequence; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D002417:Cattle; D002478:Cells, Cultured; D020219:Chondrogenesis / Q000502:physiology; D011508:Chondroitin Sulfate Proteoglycans / Q000235:genetics; D003094:Collagen / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D016326:Extracellular Matrix Proteins; D017102:Fracture Healing / Q000502:physiology; D015870:Gene Expression / Q000187:drug effects; D037181:Lectins, C-Type; D008833:Microcirculation / Q000166:cytology; D020286:Pericytes / Q000187:drug effects* / Q000378:metabolism*; D010641:Phenotype; D011509:Proteoglycans / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016212:Transforming Growth Factor beta; D053675:Versicans
chemical_list: D053674:Aggrecans; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D011508:Chondroitin Sulfate Proteoglycans; D017931:DNA Primers; D016326:Extracellular Matrix Proteins; D037181:Lectins, C-Type; D011509:Proteoglycans; D012333:RNA, Messenger; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D053675:Versicans; D003094:Collagen