title: Perlecan modulates VEGF signaling and is essential for vascularization in endochondral bone formation.
abstract: Perlecan (Hspg2) is a heparan sulfate proteoglycan expressed in basement membranes and cartilage. Perlecan deficiency (Hspg2(-/-)) in mice and humans causes lethal chondrodysplasia, which indicates that perlecan is essential for cartilage development. However, the function of perlecan in endochondral ossification is not clear. Here, we report the critical role of perlecan in VEGF signaling and angiogenesis in growth plate formation. The Hspg2(-/-) growth plate was significantly wider but shorter due to severely impaired endochondral bone formation. Hypertrophic chondrocytes were differentiated in Hspg2(-/-) growth plates; however, removal of the hypertrophic matrix and calcified cartilage was inhibited. Although the expression of MMP-13, CTGF, and VEGFA was significantly upregulated in Hspg2(-/-) growth plates, vascular invasion into the hypertrophic zone was impaired, which resulted in an almost complete lack of bone marrow and trabecular bone. We demonstrated that cartilage perlecan promoted activation of VEGF/VEGFR by binding to the VEGFR of endothelial cells. Expression of the perlecan transgene specific to the cartilage of Hspg2(-/-) mice rescued their perinatal lethality and growth plate abnormalities, and vascularization into the growth plate was restored, indicating that perlecan in the growth plate, not in endothelial cells, is critical in this process. These results suggest that perlecan in cartilage is required for activating VEGFR signaling of endothelial cells for vascular invasion and for osteoblast migration into the growth plate. Thus, perlecan in cartilage plays a critical role in endochondral bone formation by promoting angiogenesis essential for cartilage matrix remodeling and subsequent endochondral bone formation.
authors.affiliation: Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892-4370, USA.
authors.forename: Muneaki
authors.initials: M
authors.lastname: Ishijima
authors.forename: Nobuharu
authors.initials: N
authors.lastname: Suzuki
authors.forename: Kentaro
authors.initials: K
authors.lastname: Hozumi
authors.forename: Tomoya
authors.initials: T
authors.lastname: Matsunobu
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kosaki
authors.forename: Haruka
authors.initials: H
authors.lastname: Kaneko
authors.forename: John R
authors.initials: JR
authors.lastname: Hassell
authors.forename: Eri
authors.initials: E
authors.lastname: Arikawa-Hirasawa
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Yamada
mesh_terms: D000818:Animals; D001485:Basement Membrane / Q000378:metabolism; D001853:Bone Marrow / Q000378:metabolism / Q000473:pathology; D002356:Cartilage / Q000378:metabolism / Q000473:pathology; D002454:Cell Differentiation; D002465:Cell Movement; D019902:Chondrocytes / Q000378:metabolism / Q000473:pathology; D004622:Embryo, Mammalian / Q000196:embryology / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism / Q000473:pathology; D006132:Growth Plate / Q000378:metabolism / Q000473:pathology; D019812:Heparan Sulfate Proteoglycans / Q000235:genetics / Q000378:metabolism*; D006984:Hypertrophy / Q000378:metabolism; D053509:Matrix Metalloproteinase 13 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic / Q000235:genetics / Q000378:metabolism; D009389:Neovascularization, Pathologic / Q000378:metabolism*; D010006:Osteoblasts / Q000378:metabolism; D010012:Osteogenesis; D015398:Signal Transduction; D019076:Transgenes; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: D019812:Heparan Sulfate Proteoglycans; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; C071927:perlecan; D053509:Matrix Metalloproteinase 13; C507081:Mmp13 protein, mouse