title: Bone morphogenetic protein 4 (BMP4): a regulator of capsule chondrogenesis in the developing mouse inner ear.
abstract: Formation of the cartilaginous otic capsule is directed by otic epithelial-periotic mesenchymal interactions. In response to induction by otic epithelium, condensations of mesenchyme appear in the periotic region and form a chondrified otic capsule that serves as the template for the subsequent formation of the endochondral bony labyrinth. Previous studies indicate that members of the transforming growth factor beta superfamily, including transforming growth factor beta(1), participate in guiding these tissue interactions. In this study, we report the localization of bone morphogenetic protein 4 (BMP4) to the mesenchymal and epithelial-derived tissues of the mouse inner ear between 10.5 and 14 days of embryonic development. We demonstrate modulation of chondrogenesis in cultured mouse periotic mesenchyme by exogenous BMP4 protein and investigate the function of endogenous BMP4 in otic capsule chondrogenesis. We show that in the presence of the BMP antagonist, Noggin, otic capsule chondrogenesis is suppressed in culture in a dose-dependent manner. Consistent with this finding, addition of BMP4-specific antisense oligonucleotide to cultures of mouse periotic mesenchyme containing otic epithelium decreases levels of endogenous BMP4 protein and suppresses the chondrogenic response of the cultured periotic mesenchyme, providing evidence of the necessity for BMP4 in mediating otic capsule chondrogenesis. Supplementation of either Noggin- or BMP4 antisense oligonucleotide-treated cultures with BMP4 protein can restore the extent of chondrogenesis to normal levels. Our findings support BMP4 as an essential mediator of chondrogenesis in the developing otic capsule in situ.
authors.affiliation: Department of Otolaryngology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Seung Ha
authors.initials: SH
authors.lastname: Oh
authors.forename: Yong koo
authors.initials: Yk
authors.lastname: Kang Yk
authors.forename: Geming
authors.initials: G
authors.lastname: Li
authors.forename: Thao M
authors.initials: TM
authors.lastname: Doan
authors.forename: Markus
authors.initials: M
authors.lastname: Little
authors.forename: Lijun
authors.initials: L
authors.lastname: Li
authors.forename: Kyung
authors.initials: K
authors.lastname: Ahn
authors.forename: E Bryan
authors.initials: EB
authors.lastname: Crenshaw
authors.forename: Dorothy A
authors.initials: DA
authors.lastname: Frenz
mesh_terms: D000818:Animals; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D002352:Carrier Proteins; D002478:Cells, Cultured; D020219:Chondrogenesis / Q000502:physiology*; D007758:Ear, Inner / Q000737:chemistry / Q000166:cytology / Q000196:embryology*; D004847:Epithelial Cells / Q000737:chemistry / Q000166:cytology; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008648:Mesoderm / Q000737:chemistry / Q000166:cytology; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D011247:Pregnancy; D011506:Proteins / Q000494:pharmacology; D000099176:Noggin Protein
chemical_list: D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D016376:Oligonucleotides, Antisense; D011506:Proteins; D000099176:Noggin Protein; C525810:Bmp4 protein, mouse