title: Cellular origin of microfibrils explored by monensin-induced perturbation of secretory activity in embryonic primary cultures.
abstract: Fibrillin is a primary component of elastin-associated microfibrils. Since microfibrils are distributed rather ubiquitously in embryonic tissues, attention has focused on the types of cells responsible for producing fibrillin. To clarify this issue, we employed monensin-induced perturbation of secretory activity in embryonic primary cultures, as this would allow examination of both the secreted protein and the formation of extracellular fibrils in the same culture. Micromasses of avian limb bud mesoderm, its ectodermal covering and several explants from other sources were cultured in the presence and absence of monensin, and evaluated immunohistochemically using antibodies against fibrillin and cell lineage markers. The results indicated that monensin perturbation induced intracellular accumulation of fibrillin and prevented the formation of microfibrils. It was shown specifically that not only mesodermally derived fibrogenic cells and myogenic cells of skeletal and smooth muscle cell lineage, but also epithelial-type cells such as endothelial and ectodermal cells, are producers of fibrillin. This dual cellular origin of fibrillin at the ectomesenchymal interface is considered significant for understanding the formation and remodeling of microfibrils originating from the basal lamina.
authors.affiliation: Department of Anatomy, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Yamazaki
authors.forename: Hitomi
authors.initials: H
authors.lastname: Sejima
authors.forename: Maki
authors.initials: M
authors.lastname: Yuguchi
authors.forename: Keizo
authors.initials: K
authors.lastname: Shinozuka
authors.forename: Keitaro
authors.initials: K
authors.lastname: Isokawa
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D019070:Cell Lineage; D002642:Chick Embryo; D004475:Ectoderm / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D000071837:Fibrillins; D006651:Histocytochemistry; D007476:Ionophores / Q000494:pharmacology*; D008648:Mesoderm / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D020894:Microfibrils; D008840:Microfilament Proteins / Q000378:metabolism*; D008985:Monensin / Q000494:pharmacology*; D032342:Muscle Cells / Q000378:metabolism; D009206:Myocardium / Q000166:cytology; D021381:Protein Transport / Q000187:drug effects
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D000071837:Fibrillins; D007476:Ionophores; D008840:Microfilament Proteins; D008985:Monensin; C118089:TFPT protein, human