title: Bone morphogenetic protein 2 signaling in osteoclasts is negatively regulated by the BMP antagonist, twisted gastrulation.
abstract: Bone morphogenetic proteins (BMPs) have been shown to regulate both osteoblasts and osteoclasts. We previously reported that BMP2 could directly enhance RANKL-mediated osteoclast differentiation by increasing the size and number of osteoclasts. Similarly, genetic deletion of the BMP antagonist Twisted gastrulation (TWSG1) in mice, resulted in an enhancement of osteoclast formation, activity and osteopenia. This was accompanied by increased levels of phosphorylated Smad (pSmad) 1/5/8 in Twsg1(-/-) osteoclasts in vitro. The purpose of this study was to develop an adenoviral vector overexpressing Twsg1 as a means of inhibiting osteoclast activity. We demonstrate that overexpressing TWSG1 in primary osteoclasts decreased the size and number of multinuclear TRAP-positive osteoclasts, expression of osteoclast genes, and resorption ability. Overexpression of TWSG1 did not affect osteoclast proliferation or apoptosis. However, overexpression of TWSG1 decreased the levels of pSmad 1/5/8 in osteoclasts. Addition of exogenous BMP2 to osteoclasts overexpressing TWSG1 rescued the size and levels of pSmad 1/5/8 compared to cultures infected with a control virus. Finally, TWSG1 overexpression in osteoclasts isolated from the Twsg1(-/-) mice rescued size of the osteoclasts while further addition of exogenous BMP2 reversed the effect of TWSG1 overexpression and increased the size of the osteoclasts similar to control virus infected cells. Taken together, we demonstrate that overexpressing TWSG1 in osteoclasts via an adenoviral vector results in inhibition of osteoclastogenesis and may provide a potential therapy for inhibiting osteoclast activity in a localized manner.
authors.affiliation: Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota 55455, USA.
authors.forename: Lan
authors.initials: L
authors.lastname: Pham
authors.forename: Kayla
authors.initials: K
authors.lastname: Beyer
authors.forename: Eric D
authors.initials: ED
authors.lastname: Jensen
authors.forename: Julio Sotillo
authors.initials: JS
authors.lastname: Rodriguez
authors.forename: Julia
authors.initials: J
authors.lastname: Davydova
authors.forename: Masato
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Anna
authors.initials: A
authors.lastname: Petryk
authors.forename: Rajaram
authors.initials: R
authors.lastname: Gopalakrishnan
authors.forename: Kim C
authors.initials: KC
authors.lastname: Mansky
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D055396:Bone Morphogenetic Protein 2 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002454:Cell Differentiation; D049109:Cell Proliferation; D048429:Cell Size; D015536:Down-Regulation; D017353:Gene Deletion; D005822:Genetic Vectors; D051379:Mice; D057507:Mice, 129 Strain; D018345:Mice, Knockout; D010010:Osteoclasts / Q000166:cytology* / Q000821:virology; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D053245:RANK Ligand / Q000494:pharmacology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D051785:Smad Proteins / Q000378:metabolism
chemical_list: C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D011506:Proteins; D053245:RANK Ligand; D011994:Recombinant Proteins; D051785:Smad Proteins; C505689:Tnfsf11 protein, mouse; C473561:twisted gastrulation protein, mouse