title: Fibromodulin Expression in Folliculostellate Cells and Pericytes Is Promoted by TGFβ Signaling in Rat Anterior Pituitary Gland.
abstract: Fibromodulin belongs to the family of small leucine-rich proteoglycans (SLRPs), an active component of extracellular matrix. It directly binds collagens to promote fibrillogenesis and also binds transforming growth factor-beta (TGFβ) to antagonize its actions. Our previous studies of rat anterior pituitary gland revealed that fibromodulin is expressed in folliculostellate cells and pericytes. Although our recent study showed that TGFβ2 secreted from folliculostellate cells induces collagen synthesis in pericytes, the involvement of fibromodulin in TGFβ2-mediated collagen regulation has not been studied. The present study examined the effect of TGFβ2 on fibromodulin synthesis in rat anterior pituitary gland.In situhybridization for TGFβ receptor II and immunohistological techniques revealed the presence of TGFβ receptor II in folliculostellate cells and pericytes. To confirm canonical TGFβ intracellular signaling, Smad2 immunocytochemistry was performed. Nuclear translocation of Smad2 was observed in folliculostellate cells and pericytes after TGFβ2 treatment. TGFβ2 strongly enhanced fibromodulin mRNA and protein expressions, and TGFβ2-induced mRNA expression was completely blocked by TGFβ receptor I inhibitor (SB431542). These results suggest that folliculostellate cells and pericytes exhibit canonical TGFβ2 signaling, which is associated with fibromodulin production. Thus, this is the first report to show that TGFβ signaling regulates the endogenous TGFβ antagonist fibromodulin in the gland.
authors.affiliation: Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine , Tochigi, Japan.
authors.forename: Rahimi
authors.initials: R
authors.lastname: Syaidah
authors.affiliation: Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine , Tochigi, Japan.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Tsukada
authors.affiliation: Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine , Tochigi, Japan.
authors.forename: Morio
authors.initials: M
authors.lastname: Azuma
authors.affiliation: Laboratory of Anatomy and Cell Biology, Department of Health Sciences, Kyorin University , Tokyo, Japan.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Horiguchi
authors.affiliation: Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine , Tochigi, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Fujiwara
authors.affiliation: Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine, Tochigi, Japan; Laboratory of Natural History, Jichi Medical University School of Medicine, Tochigi, Japan.
authors.forename: Motoshi
authors.initials: M
authors.lastname: Kikuchi
authors.affiliation: Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine , Tochigi, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yashiro
keywords: fibromodulin; folliculostellate cell; pericyte; small leucine-rich proteoglycans; transforming growth factor beta