title: Connexin 43 Is Necessary for Salivary Gland Branching Morphogenesis and FGF10-induced ERK1/2 Phosphorylation.
abstract: Cell-cell interaction via the gap junction regulates cell growth and differentiation, leading to formation of organs of appropriate size and quality. To determine the role of connexin43 in salivary gland development, we analyzed its expression in developing submandibular glands (SMGs). Connexin43 (Cx43) was found to be expressed in salivary gland epithelium. In ex vivo organ cultures of SMGs, addition of the gap junctional inhibitors 18α-glycyrrhetinic acid (18α-GA) and oleamide inhibited SMG branching morphogenesis, suggesting that gap junctional communication contributes to salivary gland development. In Cx43(-/-) salivary glands, submandibular and sublingual gland size was reduced as compared with those from heterozygotes. The expression of Pdgfa, Pdgfb, Fgf7, and Fgf10, which induced branching of SMGs in Cx43(-/-) samples, were not changed as compared with those from heterozygotes. Furthermore, the blocking peptide for the hemichannel and gap junction channel showed inhibition of terminal bud branching. FGF10 induced branching morphogenesis, while it did not rescue the Cx43(-/-) phenotype, thus Cx43 may regulate FGF10 signaling during salivary gland development. FGF10 is expressed in salivary gland mesenchyme and regulates epithelial proliferation, and was shown to induce ERK1/2 phosphorylation in salivary epithelial cells, while ERK1/2 phosphorylation in HSY cells was dramatically inhibited by 18α-GA, a Cx43 peptide or siRNA. On the other hand, PDGF-AA and PDGF-BB separately induced ERK1/2 phosphorylation in primary cultured salivary mesenchymal cells regardless of the presence of 18α-GA. Together, our results suggest that Cx43 regulates FGF10-induced ERK1/2 phosphorylation in salivary epithelium but not in mesenchyme during the process of SMG branching morphogenesis.
authors.affiliation: From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences.
authors.forename: Aya
authors.initials: A
authors.lastname: Yamada
authors.affiliation: From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Futagi
authors.affiliation: From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences.
authors.forename: Emiko
authors.initials: E
authors.lastname: Fukumoto
authors.affiliation: From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences.
authors.forename: Kan
authors.initials: K
authors.lastname: Saito
authors.affiliation: Division of Orthodontics, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan.
authors.forename: Keigo
authors.initials: K
authors.lastname: Yoshizaki
authors.affiliation: Operative Dentistry, Department of Restorative Dentistry Tohoku University Graduate School of Dentistry, Sendai 980-8575, Japan and.
authors.forename: Masaki
authors.initials: M
authors.lastname: Ishikawa
authors.affiliation: From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences.
authors.forename: Makiko
authors.initials: M
authors.lastname: Arakaki
authors.affiliation: From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences.
authors.forename: Ryoko
authors.initials: R
authors.lastname: Hino
authors.affiliation: From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences.
authors.forename: Yu
authors.initials: Y
authors.lastname: Sugawara
authors.affiliation: From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences.
authors.forename: Momoko
authors.initials: M
authors.lastname: Ishikawa
authors.affiliation: From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Naruse
authors.affiliation: Division of Orthodontics, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Miyazaki
authors.affiliation: From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences, fukumoto@dent.tohoku.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fukumoto
mesh_terms: D000818:Animals; D000077214:Becaplermin; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002460:Cell Line; D018031:Connexin 43 / Q000172:deficiency / Q000378:metabolism*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D051526:Fibroblast Growth Factor 10 / Q000494:pharmacology*; D051523:Fibroblast Growth Factor 7 / Q000494:pharmacology; D017629:Gap Junctions / Q000187:drug effects / Q000378:metabolism; D006034:Glycyrrhetinic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D008813:Mice, Inbred ICR; D018345:Mice, Knockout; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009024:Morphogenesis / Q000187:drug effects*; D009829:Oleic Acids / Q000494:pharmacology; D009924:Organ Culture Techniques; D010455:Peptides / Q000494:pharmacology; D010641:Phenotype; D010766:Phosphorylation / Q000187:drug effects; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D020574:Proto-Oncogene Proteins c-sis / Q000494:pharmacology; D051496:Receptor, Fibroblast Growth Factor, Type 1 / Q000378:metabolism; D051497:Receptor, Fibroblast Growth Factor, Type 2 / Q000378:metabolism; D013361:Sublingual Gland / Q000187:drug effects / Q000196:embryology* / Q000201:enzymology*
chemical_list: D019485:Bone Morphogenetic Proteins; D018031:Connexin 43; D051526:Fibroblast Growth Factor 10; D009829:Oleic Acids; D010455:Peptides; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; C075278:platelet-derived growth factor A; D051523:Fibroblast Growth Factor 7; C119129:18alpha-glycyrrhetinic acid; D000077214:Becaplermin; C029407:oleylamide; D051496:Receptor, Fibroblast Growth Factor, Type 1; D051497:Receptor, Fibroblast Growth Factor, Type 2; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D006034:Glycyrrhetinic Acid
keywords: branching morphogenesis; connexin; extracellular-signal-regulated kinase (ERK); fibroblast growth factor (FGF); gap junction; phosphorylation; salivary gland