title: Skeletal Characterization of Smurf2-Deficient Mice and In Vitro Analysis of Smurf2-Deficient Chondrocytes.
abstract: Overexpression of Smad ubiquitin regulatory factor 2 (Smurf2) in chondrocytes was reported to cause spontaneous osteoarthritis (OA) in mice. However, it is unclear whether Smurf2 is involved in bone and cartilage homeostasis and if it is required for OA pathogenesis. Here we characterized age-related changes in the bone and articular cartilage of Smurf2-deficient (MT) mice by microCT and histology, and examined whether reduced Smurf2 expression affected the severity of OA upon surgical destabilization of the medial meniscus (DMM). Using immature articular chondrocytes (iMAC) from MT and wild-type (WT) mice, we also examined how Smurf2 deficiency affects chondrogenic and catabolic gene expressions and Smurf2 and Smurf1 proteins upon TGF-β3 or IL-1β treatment in culture. We found no differences in cortical, subchondral and trabecular bone between WT and MT in young (4 months) and old mice (16-24 months). The articular cartilage and age-related alterations between WT and MT were also similar. However, 2 months following DMM, young MT showed milder OA compared to WT (~70% vs ~30% normal or exhibiting only mild OA cartilage phenotype). The majority of the older WT and MT mice developed moderate/severe OA 2 months after DMM, but a higher subset of aged MT cartilage (27% vs. 9% WT) remained largely normal. Chondrogenic gene expression (Sox9, Col2, Acan) trended higher in MT iMACs than WT with/without TGF-β3 treatment. IL-1β treatment suppressed chondrgenic gene expression, but Sox9 expression in MT remained significantly higher than WT. Smurf2 protein in WT iMACs increased upon TGF-β3 treatment and decreased upon IL-1β treatment in a dose-dependent manner. Smurf1 protein elevated more in MT than WT upon TGF-β3 treatment, suggesting a potential, but very mild compensatory effect. Overall, our data support a role of Smurf2 in regulating OA development but suggest that inhibiting Smurf2 alone may not be sufficient to prevent or consistently mitigate post-traumatic OA across a broad age range.
authors.affiliation: Department of Orthopedics and Physical Rehabilitation, University of Massachusetts Medical School, Worcester, MA, United States of America.|Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America.
authors.forename: Henry
authors.initials: H
authors.lastname: Huang
authors.affiliation: Department of Orthopedics and Physical Rehabilitation, University of Massachusetts Medical School, Worcester, MA, United States of America.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Veien
authors.affiliation: Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Orthopedics and Physical Rehabilitation, University of Massachusetts Medical School, Worcester, MA, United States of America.
authors.forename: David C
authors.initials: DC
authors.lastname: Ayers
authors.affiliation: Department of Orthopedics and Physical Rehabilitation, University of Massachusetts Medical School, Worcester, MA, United States of America.|Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America.
authors.forename: Jie
authors.initials: J
authors.lastname: Song
mesh_terms: D000375:Aging; D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology*; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism / Q000473:pathology*; D004195:Disease Models, Animal; D005260:Female; D017353:Gene Deletion; D053583:Interleukin-1beta / Q000378:metabolism; D007719:Knee Joint; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology / Q000601:surgery; D051379:Mice; D008810:Mice, Inbred C57BL; D020370:Osteoarthritis, Knee / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D053782:Transforming Growth Factor beta3 / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism
chemical_list: D053583:Interleukin-1beta; D053782:Transforming Growth Factor beta3; C533325:Smurf2 protein, mouse; D044767:Ubiquitin-Protein Ligases
references.citation: J Orthop Res. 2008 May;26(5):704-12
references.pmid: 18176945
references.citation: Nat Med. 2012 Feb;18(2):227-34
references.pmid: 22231558
references.citation: Aging Dis. 2013 Dec 17;5(6):394-405
references.pmid: 25489490
references.citation: Int J Biol Sci. 2012;8(2):272-88
references.pmid: 22298955
references.citation: Annu Rev Biochem. 1998;67:425-79
references.pmid: 9759494
references.citation: Cell. 2005 Apr 8;121(1):101-13
references.pmid: 15820682
references.citation: Arthritis Res Ther. 2005;7(6):R1338-47
references.pmid: 16277687
references.citation: PLoS One. 2011;6(1):e16421
references.pmid: 21297990
references.citation: Cancer Res. 2012 Jun 1;72(11):2714-9
references.pmid: 22552287
references.citation: Nat Rev Rheumatol. 2012 Nov;8(11):665-73
references.pmid: 22868925
references.citation: Blood. 2012 Mar 15;119(11):e86-95
references.pmid: 22262767
references.citation: Arthritis Rheum. 2010 Aug;62(8):2359-69
references.pmid: 20506210
references.citation: Arthritis Rheum. 2001 Mar;44(3):585-94
references.pmid: 11263773
references.citation: Ann Rheum Dis. 2006 Nov;65(11):1414-21
references.pmid: 16439443
references.citation: Osteoarthritis Cartilage. 2010 Oct;18 Suppl 3:S17-23
references.pmid: 20864019
references.citation: Osteoarthritis Cartilage. 2012 Aug;20(8):949-56
references.pmid: 22595226
references.citation: EMBO J. 2011 Nov 30;30(23):4777-89
references.pmid: 22045334
references.citation: Mol Cell. 2000 Dec;6(6):1365-75
references.pmid: 11163210
references.citation: Cancer Sci. 2008 Nov;99(11):2107-12
references.pmid: 18808420
references.citation: Nature. 2012 Feb 23;482(7386):495-500
references.pmid: 22358839
references.citation: Arthritis Rheum. 2008 Oct;58(10):3132-44
references.pmid: 18821706
references.citation: J Biol Chem. 2000 Nov 24;275(47):36818-22
references.pmid: 11016919
references.citation: J Cell Biol. 1997 Oct 20;139(2):541-52
references.pmid: 9334355
references.citation: Osteoarthritis Cartilage. 2007 Jun;15(6):597-604
references.pmid: 17391995
references.citation: J Cell Biol. 2001 Apr 2;153(1):35-46
references.pmid: 11285272
references.citation: Rheumatol Int. 2005 Mar;25(2):118-24
references.pmid: 14618374
references.citation: J Bone Miner Res. 2007 Aug;22(8):1197-207
references.pmid: 17488199
references.citation: J Cell Biochem. 2010 Jun 1;110(3):554-63
references.pmid: 20512916
references.citation: Bone. 2009 Sep;45(3):414-22
references.pmid: 19481620
references.citation: J Bone Miner Res. 2002 Jun;17(6):1044-50
references.pmid: 12054159
references.citation: J Cell Biochem. 2012 Jan;113(1):238-46
references.pmid: 21898545
references.citation: Nat Protoc. 2008;3(8):1253-60
references.pmid: 18714293
references.citation: Bone Res. 2015 Apr 14;3:15005
references.pmid: 26273537
references.citation: J Orthop Surg (Hong Kong). 2005 Apr;13(1):8-18
references.pmid: 15872395
references.citation: J Gerontol A Biol Sci Med Sci. 2013 Oct;68(10):1218-25
references.pmid: 23833200
references.citation: Osteoarthritis Cartilage. 2007 Sep;15(9):1061-9
references.pmid: 17470400
references.citation: Front Biosci. 2007;12:536-50
references.pmid: 17127315
references.citation: FEBS Lett. 1988 Jul 4;234(1):172-6
references.pmid: 3164687