title: The p66Shc adapter protein regulates the morphogenesis and epithelial maturation of fetal mouse lungs.
abstract: Many signaling pathways are mediated by Shc adapter proteins that, in turn, are expressed as three isoforms with distinct functions. The p66(Shc) isoform antagonizes proliferation, regulates oxidative stress, and mediates apoptosis. It is highly expressed in the canalicular but not the later stages of mouse lung development, and its expression persists in bronchopulmonary dysplasia, a chronic disease associated with premature birth. These observations suggest that p66(Shc) has a developmental function. However, constitutive p66(Shc) deletion yields no morphological phenotype, and the structure of the Shc gene precludes its inducible deletion. To elucidate its function in lung development, we transfected p66(Shc) or nonsilencing small-interfering RNA (siRNA) into the epithelia of embryonic day 11 mouse lungs that were then cultured for 3 days and analyzed morphometrically. To assess cellular proliferation and epithelial differentiation, lung explants were immunostained and immunoblotted for p66(Shc), proliferating cell nuclear antigen (PCNA), the proximal airway differentiation antigens Clara cell 10-kDa protein (CC10) and thyroid transcription factor (TTF)-1, and the alveolar surfactant proteins (SP)-A, -B, and -C. Explants transfected with nonsilencing siRNA demonstrated specific epithelial uptake and normal morphological development relative to uninjected controls. In contrast, transfection with p66(Shc) siRNA significantly increased lumenal cross-sectional areas, decreased branching, and increased epithelial proliferation (P < 0.05 for all). Relative to controls, the expression of SP-B, SP-C, CC10, and TTF-1 was decreased by p66(Shc) knockdown. SP-A was not expressed in either control or treated lungs. These data suggest that p66(Shc) attenuates epithelial proliferation while promoting both distal and proximal epithelial maturation.
authors.affiliation: General Laboratories Bldg., 1201 E. Marengo St., Los Angeles, CA 90033. mattlee@usc.edu.
authors.forename: M K
authors.initials: MK
authors.lastname: Lee
authors.forename: S M
authors.initials: SM
authors.lastname: Smith
authors.forename: Maalika M
authors.initials: MM
authors.lastname: Banerjee
authors.forename: Changgong
authors.initials: C
authors.lastname: Li
authors.forename: Parviz
authors.initials: P
authors.lastname: Minoo
authors.forename: M V
authors.initials: MV
authors.lastname: Volpe
authors.forename: H C
authors.initials: HC
authors.lastname: Nielsen
mesh_terms: D016475:3T3 Cells; D056809:Alveolar Epithelial Cells / Q000502:physiology*; D000818:Animals; D002454:Cell Differentiation; D004268:DNA-Binding Proteins / Q000378:metabolism; D005260:Female; D055785:Gene Knockdown Techniques; D008168:Lung / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D051379:Mice; D009024:Morphogenesis; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D037701:Pulmonary Surfactant-Associated Protein B / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D055765:Shc Signaling Adaptor Proteins / Q000502:physiology*; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D046509:Tissue Culture Techniques; D014157:Transcription Factors; D014598:Uteroglobin / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D018809:Proliferating Cell Nuclear Antigen; D037701:Pulmonary Surfactant-Associated Protein B; D034741:RNA, Small Interfering; C556390:Scgb1a1 protein, mouse; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014157:Transcription Factors; C504004:Ttf1 protein, mouse; D014598:Uteroglobin
keywords: bronchopulmonary dysplasia; extracellular signal-regulated kinase; lung maturation; mitogen-activated protein kinase; surfactant