TY - JOUR
T1 - VEGFA From Early Osteoblast Lineage Cells (Osterix+) Is Required in Mice for Fracture Healing
AU - Buettmann, Evan G.
AU - McKenzie, Jennifer A.
AU - Migotsky, Nicole
AU - Sykes, David A.W.
AU - Hu, Pei
AU - Yoneda, Susumu
AU - Silva, Matthew J.
N1 - Funding Information:
This work was supported by funding from NIAMS (R01 AR050211 and P30 AR057235). The authors would like to thank the Washington University in St. Louis Musculoskeletal Research Center (MRC) Cores and staff for assistance. Thanks to Dan Leib for training and assistance in Xray (Faxitron) and micro-CT (Scanco) image acquisition and analysis. Many thanks to Crystal Idleburg and Samantha Coleman for histological processing and sectioning of all bone repair specimens. Thanks to Dr. Michael Ross from the Weilbacher Laboratory (Washington University School of Medicine) for supplying protocols and assistance with endomucin staining. Histological images were taken with the Nanozoomer at Alafi Neuroimaging Core (S10 RR027552). VEGFAfl/fl mice from Genentech (Roche Holding AG) were kindly provided by the lab of Bjorn Olsen (Harvard). Inducible Osx Cre-ERT2 were kindly provided by the lab of Henry Kronenberg (Harvard). Inducible Dmp1 Cre-ERT2 from Paolo Pajevic (Boston University) were kindly provided by the lab of Alexander Robling (Indiana University Medical School). Authors? Roles: Study design: MJS, JAM, EGB. Study conduct: EGB, JAM, NM, DAWS, PH, SY. Data collection: EGB, JAM, NM, DAWS, PH, SY. Data analysis: EGB, JAM, DAWS. Data interpretation: EGB, JAM, MJS. Drafting manuscript: EGB. Revising manuscript: EGB, JAM, MJS. Approving final version of manuscript: EGB, JAM, MJS. EGB takes responsibility for integrity of data analysis.
Publisher Copyright:
© 2019 American Society for Bone and Mineral Research
PY - 2019/9/1
Y1 - 2019/9/1
N2 - Bone formation via intramembranous and endochondral ossification is necessary for successful healing after a wide range of bone injuries. The pleiotropic cytokine, vascular endothelial growth factor A (VEGFA) has been shown, via nonspecific pharmacologic inhibition, to be indispensable for angiogenesis and ossification following bone fracture and cortical defect repair. However, the importance of VEGFA expression by different cell types during bone healing is not well understood. We sought to determine the role of VEGFA from different osteoblast cell subsets following clinically relevant models of bone fracture and cortical defect. Ubiquitin C (UBC), Osterix (Osx), or Dentin matrix protein 1 (Dmp1) Cre-ERT2 mice (male and female) containing floxed VEGFA alleles (VEGFAfl/fl) were either given a femur full fracture, ulna stress fracture, or tibia cortical defect at 12 weeks of age. All mice received tamoxifen continuously starting 2 weeks before bone injury and throughout healing. UBC Cre-ERT2 VEGFAfl/fl (UBC cKO) mice, which were used to mimic nonspecific inhibition, had minimal bone formation and impaired angiogenesis across all bone injury models. UBC cKO mice also exhibited impaired periosteal cell proliferation during full fracture, but not stress fracture repair. Osx Cre-ERT2 VEGFAfl/fl (Osx cKO) mice, but not Dmp1 Cre-ERT2 VEGFAfl/fl (Dmp1 cKO) mice, showed impaired periosteal bone formation and angiogenesis in models of full fracture and stress fracture. Neither Osx cKO nor Dmp1 cKO mice demonstrated significant impairments in intramedullary bone formation and angiogenesis following cortical defect. These data suggest that VEGFA from early osteolineage cells (Osx+), but not mature osteoblasts/osteocytes (Dmp1+), is critical at the time of bone injury for rapid periosteal angiogenesis and woven bone formation during fracture repair. Whereas VEGFA from another cell source, not from the osteoblast cell lineage, is necessary at the time of injury for maximum cortical defect intramedullary angiogenesis and osteogenesis.
AB - Bone formation via intramembranous and endochondral ossification is necessary for successful healing after a wide range of bone injuries. The pleiotropic cytokine, vascular endothelial growth factor A (VEGFA) has been shown, via nonspecific pharmacologic inhibition, to be indispensable for angiogenesis and ossification following bone fracture and cortical defect repair. However, the importance of VEGFA expression by different cell types during bone healing is not well understood. We sought to determine the role of VEGFA from different osteoblast cell subsets following clinically relevant models of bone fracture and cortical defect. Ubiquitin C (UBC), Osterix (Osx), or Dentin matrix protein 1 (Dmp1) Cre-ERT2 mice (male and female) containing floxed VEGFA alleles (VEGFAfl/fl) were either given a femur full fracture, ulna stress fracture, or tibia cortical defect at 12 weeks of age. All mice received tamoxifen continuously starting 2 weeks before bone injury and throughout healing. UBC Cre-ERT2 VEGFAfl/fl (UBC cKO) mice, which were used to mimic nonspecific inhibition, had minimal bone formation and impaired angiogenesis across all bone injury models. UBC cKO mice also exhibited impaired periosteal cell proliferation during full fracture, but not stress fracture repair. Osx Cre-ERT2 VEGFAfl/fl (Osx cKO) mice, but not Dmp1 Cre-ERT2 VEGFAfl/fl (Dmp1 cKO) mice, showed impaired periosteal bone formation and angiogenesis in models of full fracture and stress fracture. Neither Osx cKO nor Dmp1 cKO mice demonstrated significant impairments in intramedullary bone formation and angiogenesis following cortical defect. These data suggest that VEGFA from early osteolineage cells (Osx+), but not mature osteoblasts/osteocytes (Dmp1+), is critical at the time of bone injury for rapid periosteal angiogenesis and woven bone formation during fracture repair. Whereas VEGFA from another cell source, not from the osteoblast cell lineage, is necessary at the time of injury for maximum cortical defect intramedullary angiogenesis and osteogenesis.
KW - CYTOKINES
KW - GENETIC ANIMAL MODELS
KW - INJURY/FRACTURE HEALING
KW - OSTEOBLASTS
UR - http://www.scopus.com/inward/record.url?scp=85070071015&partnerID=8YFLogxK
U2 - 10.1002/jbmr.3755
DO - 10.1002/jbmr.3755
M3 - Article
C2 - 31081125
AN - SCOPUS:85070071015
VL - 34
SP - 1690
EP - 1706
JO - Journal of Bone and Mineral Research
JF - Journal of Bone and Mineral Research
SN - 0884-0431
IS - 9
ER -