title: Dioxin-sensitive proteins in differentiating osteoblasts: effects on bone formation in vitro.
abstract: 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an endocrine-disrupting environmental pollutant which affects bone tissue, although the mechanistic basis of this action is far from clear. We adopted a proteome approach to investigate the disturbance of osteogenesis evoked by TCDD in an in vitro osteoblast differentiation model of rat mesenchymal stem cells. Eighteen individual proteins showed a significant change in abundance as results of ten days of TCDD exposure, at which time mRNA changes in osteoblast differentiation markers were also observed. These proteins were mostly involved in cytoskeleton organization and biogenesis, actin filament-based processes, protein transport, and folding. The alteration in cell architecture and increase in cell adhesion were confirmed by confocal microscopy. The TCDD-induced decrease in the expression of calcium-binding proteins may interfere with osteoblast calcium deposition, which was in fact reduced by TCDD. This is the first report investigating, at the protein expression level, the effect of TCDD during osteoblastic differentiation. Interestingly, MetaCore pathway analysis grouped the majority of these proteins around two principal nodes (c-fos and c-myc) suggesting that they may participate in the transcriptional activation of key pathways in TCDD-driven inhibition of osteoblast differentiation. Our findings provide evidence of new molecular players in the effects of TCDD on bone development.
authors.affiliation: Department of Environmental Health Sciences, Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: Donatella
authors.initials: D
authors.lastname: Carpi
authors.forename: Merja
authors.initials: M
authors.lastname: Korkalainen
authors.forename: Luisa
authors.initials: L
authors.lastname: Airoldi
authors.forename: Roberto
authors.initials: R
authors.lastname: Fanelli
authors.forename: Helen
authors.initials: H
authors.lastname: Hakansson
authors.forename: Virpi
authors.initials: V
authors.lastname: Muhonen
authors.forename: Juha
authors.initials: J
authors.lastname: Tuukkanen
authors.forename: Matti
authors.initials: M
authors.lastname: Viluksela
authors.forename: Roberta
authors.initials: R
authors.lastname: Pastorelli
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001846:Bone Development / Q000187:drug effects*; D002454:Cell Differentiation / Q000187:drug effects; D004147:Dioxins / Q000633:toxicity*; D015180:Electrophoresis, Gel, Two-Dimensional; D004785:Environmental Pollutants / Q000633:toxicity*; D022001:Focal Adhesions / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D007091:Image Processing, Computer-Assisted; D008297:Male; D018613:Microscopy, Confocal; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity; D020543:Proteome / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053719:Tandem Mass Spectrometry
chemical_list: D004147:Dioxins; D004785:Environmental Pollutants; D000072317:Polychlorinated Dibenzodioxins; D020543:Proteome