title: The study of abnormal bone development in the Apert syndrome Fgfr2+/S252W mouse using a 3D hydrogel culture model.
abstract: Apert syndrome is caused by mutations in fibroblast growth factor receptor 2 (Fgfr2) and is characterized by craniosynostosis and other skeletal abnormalities. The Apert syndrome Fgfr2+/S252W mouse model exhibits perinatal lethality. A 3D hydrogel culture model, derived from tissue engineering strategies, was used to extend the study of the effect of the Fgfr2+/S252W mutation in differentiating osteoblasts postnatally. We isolated cells from the long bones of Apert Fgfr2+/S252W mice (n=6) and cells from the wild-type sibling mice (n=6) to be used as controls. During monolayer expansion, Fgfr2+/S252W cells demonstrated increased proliferation and ALP activity, as well as altered responses of these cellular functions in the presence of FGF ligands with different binding specificity (FGF2 or FGF10). To better mimic the in vivo disease development scenario, cells were also encapsulated in 3D hydrogels and their phenotype in 3D in vitro culture was compared to that of in vivo tissue specimens. After 4 weeks in 3D culture in osteogenic medium, Fgfr2+/S252W cells expressed 2.8-fold more collagen type I and 3.3-fold more osteocalcin than did wild-type controls (p<0.01). Meanwhile, Fgfr2+/S252W cells showed decreased bone matrix remodeling and expressed 87% less Metalloprotease-13 and 71% less Noggin (p<0.01). The S252W mutation also led to significantly higher production of collagen type I and II in 3D as shown by immunofluorescence staining. In situ hybridization and alizarin red S staining of postnatal day 0 (P0) mouse limb sections demonstrated significantly higher levels of osteopontin expression and mineralization in Fgfr2+/S252W mice. Complementary to in vivo findings, this 3D hydrogel culture system provides an effective in vitro venue to study the pathogenesis of Apert syndrome caused by the analogous mutation in humans.
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, 45 Carleton Street, E25-342, Cambridge, MA, 02142, USA. Electronic address: fyang4@mit.edu.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, NY, USA. Electronic address: yingli.wang@mssm.edu.
authors.forename: Yingli
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering, The Johns Hopkins University, 3400 N. Charles Street, Clark 106, Baltimore, MD, 21218, USA. Electronic address: zhangzj@jhu.edu.
authors.forename: Zijun
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Biomedical Engineering, The Johns Hopkins University, 3400 N. Charles Street, Clark 106, Baltimore, MD, 21218, USA. Electronic address: humbert@jhu.edu.
authors.forename: Bryan
authors.initials: B
authors.lastname: Hsu
authors.affiliation: Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, NY, USA. Electronic address: Ethylin.Jabs@mssm.edu.
authors.forename: Ethylin Wang
authors.initials: EW
authors.lastname: Jabs
authors.affiliation: Department of Biomedical Engineering, The Johns Hopkins University, 3400 N. Charles Street, Clark 106, Baltimore, MD, 21218, USA. Electronic address: jhe@jhu.edu.
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: Elisseeff
mesh_terms: D000168:Acrocephalosyndactylia / Q000209:etiology* / Q000235:genetics / Q000473:pathology*; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D001846:Bone Development; D001842:Bone and Bones / Q000378:metabolism / Q000473:pathology*; D002113:Calcification, Physiologic; D018929:Cell Culture Techniques / Q000379:methods*; D002478:Cells, Cultured; D017931:DNA Primers; D004195:Disease Models, Animal; D020100:Hydrogels; D017403:In Situ Hybridization; D008024:Ligands; D051379:Mice; D009154:Mutation; D053495:Osteopontin / Q000378:metabolism; D051497:Receptor, Fibroblast Growth Factor, Type 2 / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D020100:Hydrogels; D008024:Ligands; D053495:Osteopontin; D051497:Receptor, Fibroblast Growth Factor, Type 2; D000469:Alkaline Phosphatase