Indian hedgehog couples chondrogenesis to osteogenesis in endochondral bone development.
Vertebrate skeletogenesis requires a well-coordinated transition from chondrogenesis to osteogenesis. Hypertrophic chondrocytes in the growth plate play a pivotal role in this transition. Parathyroid hormone-related peptide (PTHrP), synthesized in the periarticular growth plate, regulates the site at which hypertrophy occurs. By comparing PTH/PTHrP receptor(-/-)/wild-type (PPR(-/-)/wild-type) chimeric mice with IHH(-/-);PPR(-/-)/wild-type chimeric and IHH(-/-)/wild-type chimeric mice, we provide in vivo evidence that Indian hedgehog (IHH), synthesized by prehypertrophic and hypertrophic chondrocytes, regulates the site of hypertrophic differentiation by signaling to the periarticular growth plate and also determines the site of bone collar formation in the adjacent perichondrium. By providing crucial local signals from prehypertrophic and hypertrophic chondrocytes to both chondrocytes and preosteoblasts, IHH couples chondrogenesis to osteogenesis in endochondral bone development.
Chung
U I
UI
Endocrine Unit, Massachusetts General Hospital, 50 Blossom St., Boston, Massachusetts 02114, USA.
Schipani
E
E
McMahon
A P
AP
Kronenberg
H M
HM
D000818:Animals; D001846:Bone Development / Q000502:physiology*; D002356:Cartilage / Q000196:embryology / Q000254:growth & development; D002454:Cell Differentiation; D019902:Chondrocytes / Q000378:metabolism / Q000502:physiology; D020219:Chondrogenesis; D004627:Embryonic Induction; D006132:Growth Plate / Q000196:embryology / Q000254:growth & development; D053823:Hedgehog Proteins; D017403:In Situ Hybridization; D051379:Mice; D010012:Osteogenesis; D044162:Parathyroid Hormone-Related Protein; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D015398:Signal Transduction; D013977:Tibia / Q000196:embryology / Q000254:growth & development; D015534:Trans-Activators
D053823:Hedgehog Proteins; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins; D012333:RNA, Messenger; D015534:Trans-Activators