title: Periprosthetic strain magnitude-dependent upregulation of type I collagen synthesis in human osteoblasts through an ERK1/2 pathway.
abstract: Human osteoblasts sense mechanical stimulation and synthesise type I collagen in periprosthetic osseointegration following total hip arthroplasty. However, the regulation of type I collagen synthesis by periprosthetic strain is unclear because the cellular-level strain magnitude remains unknown to date. Fortunately, the tissue-level strain in implanted femurs is measurable. According to the mechanism of strain amplification, the tissue-level strain was amplified 20 times to stretch human osteoblasts in this study. Elongation of 0.8-3.2% enhanced the mRNA level of type I collagen, whereas the release of procollagen type I C propeptide only increased at 2.4% and 3.2% elongation. Type I collagen expression increased with the activation of ERK1/2 phosphorylation in a strain-magnitude-dependent manner, whereas JNK and P38 were unaffected. The responses were completely inhibited by blocking the ERK1/2 pathway with U0126. The results indicate that type I collagen synthesis in human osteoblasts depends on the level of periprosthetic strain and ERK1/2 activation.
authors.affiliation: Department of Orthopaedics, Shanghai 6th People's Hospital, Shanghai Jiaotong University, 600 Yishan Road, Shanghai, 200233, China.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Zhu
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Zhang
authors.forename: Chengtao
authors.initials: C
authors.lastname: Wang
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Peng
authors.forename: Xianlong
authors.initials: X
authors.lastname: Zhang
mesh_terms: D015153:Blotting, Western; D002461:Cell Line, Transformed; D024042:Collagen Type I / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D007595:Joint Prosthesis; D020935:MAP Kinase Signaling System; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism*; D016348:Osseointegration / Q000502:physiology*; D010006:Osteoblasts / Q000378:metabolism*; D010446:Peptide Fragments / Q000096:biosynthesis / Q000235:genetics; D011347:Procollagen / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D013314:Stress, Mechanical; D013718:Tensile Strength; D015854:Up-Regulation
chemical_list: D024042:Collagen Type I; D010446:Peptide Fragments; D011347:Procollagen; D012333:RNA, Messenger; C047202:procollagen Type I N-terminal peptide; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3