title: The Wnt/beta-catenin pathway interacts differentially with PTHrP signaling to control chondrocyte hypertrophy and final maturation.
abstract: Sequential proliferation, hypertrophy and maturation of chondrocytes are required for proper endochondral bone development and tightly regulated by cell signaling. The canonical Wnt signaling pathway acts through beta-catenin to promote chondrocyte hypertrophy whereas PTHrP signaling inhibits it by holding chondrocytes in proliferating states. Here we show by genetic approaches that chondrocyte hypertrophy and final maturation are two distinct developmental processes that are differentially regulated by Wnt/beta-catenin and PTHrP signaling. Wnt/beta-catenin signaling regulates initiation of chondrocyte hypertrophy by inhibiting PTHrP signaling activity, but it does not regulate PTHrP expression. In addition, Wnt/beta-catenin signaling regulates chondrocyte hypertrophy in a non-cell autonomous manner and Gdf5/Bmp signaling may be one of the downstream pathways. Furthermore, Wnt/beta-catenin signaling also controls final maturation of hypertrophic chondrocytes, but such regulation is PTHrP signaling-independent.
authors: Developmental Genetics Section, National Human Genome Research Institute, Bethesda, MD, USA.
authors: Xizhi
authors: X
authors: Guo
authors: Kinglun Kingston
authors: KK
authors: Mak
authors: Makoto M
authors: MM
authors: Taketo
authors: Yingzi
authors: Y
authors: Yang
mesh_terms: D000483:Alleles; D000818:Animals; D001842:Bone and Bones / Q000378:metabolism; D019902:Chondrocytes / Q000378:metabolism*; D005260:Female; D006579:Heterozygote; D006984:Hypertrophy / Q000473:pathology*; D051379:Mice; D008954:Models, Biological; D009154:Mutation; D044162:Parathyroid Hormone-Related Protein / Q000378:metabolism*; D015398:Signal Transduction; D013629:Tamoxifen / Q000494:pharmacology; D051153:Wnt Proteins / Q000378:metabolism*; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D044162:Parathyroid Hormone-Related Protein; D051153:Wnt Proteins; D051176:beta Catenin; D013629:Tamoxifen