Rapid cell culture and pre-clinical screening of a transforming growth factor-β (TGF-β) inhibitor for orthopaedics

BMC Musculoskeletal Disorders

Research Article

Alyson Morse¹  Lauren Peacock¹  Michelle M McDonald¹  Kathy Mikulec¹  Aaron Schindeler²  Renjing Liu²  Sandy Kijumnuayporn²  David G Little²  Nicole YC Yu³  Paul A Baldock⁴  Andrew J Ruys⁵ 

[1] Department of Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Locked Bag 4001, 2145, Westmead, NSW, Australia;Department of Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Locked Bag 4001, 2145, Westmead, NSW, Australia;Discipline of Paediatrics and Child Health, Faculty of Medicine, 2006, A27 University of Sydney, NSW, Australia;Department of Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Locked Bag 4001, 2145, Westmead, NSW, Australia;School of Aerospace, Mechanical and Mechatronic Engineering, J07 University of Sydney, 2006, NSW, Australia;Osteoporosis and Bone Biology Research Program, Garvan Institute of Medical Research, 384 Victoria St, 2010, Darlinghurst, NSW, Australia;School of Aerospace, Mechanical and Mechatronic Engineering, J07 University of Sydney, 2006, NSW, Australia;

关键词: Bone Formation;    Bone Mineral Content;    Osteogenic Differentiation;    Inhibitor SB431542;    Orthopaedic Application;   

DOI  :  10.1186/1471-2474-11-105

 received in 2010-01-06, accepted in 2010-05-28,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundTransforming growth factor-β (TGF-β) and bone morphogenetic proteins (BMPs) utilize parallel and related signaling pathways, however the interaction between these pathways in bone remains unclear. TGF-β inhibition has been previously reported to promote osteogenic differentiation in vitro, suggesting it may have a capacity to augment orthopaedic repair. We have explored this concept using an approach that represents a template for the testing of agents with prospective orthopaedic applications.MethodsThe effects of BMP-2, TGF-β1, and the TGF-β receptor (ALK-4/5/7) inhibitor SB431542 on osteogenic differentiation were tested in the MC3T3-E1 murine pre-osteoblast cell line. Outcome measures included alkaline phosphatase staining, matrix mineralization, osteogenic gene expression (Runx2, Alp, Ocn) and phosphorylation of SMAD transcription factors. Next we examined the effects of SB431542 in two orthopaedic animal models. The first was a marrow ablation model where reaming of the femur leads to new intramedullary bone formation. In a second model, 20 μg rhBMP-2 in a polymer carrier was surgically introduced to the hind limb musculature to produce ectopic bone nodules.ResultsBMP-2 and SB431542 increased the expression of osteogenic markers in vitro, while TGF-β1 decreased their expression. Both BMP-2 and SB431542 were found to stimulate pSMAD1 and we also observed a non-canonical repression of pSMAD2. In contrast, neither in vivo system was able to provide evidence of improved bone formation or repair with SB431542 treatment. In the marrow ablation model, systemic dosing with up to 10 mg/kg/day SB431542 did not significantly increase reaming-induced bone formation compared to vehicle only controls. In the ectopic bone model, local co-administration of 38 μg or 192 μg SB431542 did not increase bone formation.ConclusionsALK-4/5/7 inhibitors can promote osteogenic differentiation in vitro, but this may not readily translate to in vivo orthopaedic applications.

【 授权许可】

CC BY   
© Schindeler et al; licensee BioMed Central Ltd. 2010