title: GDF-5/7 and bFGF activate integrin alpha2-mediated cellular migration in rabbit ligament fibroblasts.
abstract: Cellular activities responding to growth factors are important in ligament healing. The anterior cruciate ligament (ACL) has poor healing potential compared to the medial collateral ligament (MCL). To assess the differences, we investigated the proliferation, migration, adhesion, and matrix synthesis responding to growth factors in rabbit ACL and MCL fibroblasts. ACL cell proliferation to basic fibroblast growth factor (bFGF), bone morphogenetic protein-2, growth and differentiation factor (GDF)-5, and GDF-7 treatment was similar to that of MCL cells. GDF-5 enhanced Col1a1 expression in ACL and MCL fibroblasts up to 4.7- and 17-fold levels of control, respectively. MCL fibroblasts showed stronger migration activities in response to bFGF and GDF-5 than ACL cells. GDF-5/7 and bFGF also changed the stress fiber formation and cellular adhesion by modulating the distribution of integrin alpha2. Functional blocking analyses using anti-integrin alpha2 antibodies revealed that cellular migration responding to growth factors depended on the integrin alpha2-mediated adhesion on type I collagen. The expression of integrin alpha2 was also increased by growth factors in both cells. Our results demonstrate that GDF-5/7 and bFGF stimulate cellular migration by modulating integrin alpha2 expression and integrin alpha2-dependent adhesion, especially in MCL fibroblasts. These findings suggest that the different healing potential between ACL and MCL may be caused by different cellular behavior in the integrin alpha2-mediated cellular migration in response to growth factors.
authors.affiliation: Department of Orthopaedic Surgery, Science of Functional Recovery and Reconstruction, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Kitaku, Okayama 700-8558, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Date
authors.forename: Takayuki
authors.initials: T
authors.lastname: Furumatsu
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Sakoma
authors.forename: Aki
authors.initials: A
authors.lastname: Yoshida
authors.forename: Yuko
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Abe
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Ozaki
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000166:cytology / Q000502:physiology*; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002448:Cell Adhesion; D002465:Cell Movement / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D024042:Collagen Type I / Q000235:genetics; D000090602:Collagen Type I, alpha 1 Chain; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism*; D015870:Gene Expression / Q000502:physiology; D055428:Growth Differentiation Factor 5 / Q000378:metabolism*; D039421:Integrin alpha2 / Q000378:metabolism*; D017888:Medial Collateral Ligament, Knee / Q000166:cytology / Q000502:physiology*; D011817:Rabbits
chemical_list: D019485:Bone Morphogenetic Proteins; D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D055428:Growth Differentiation Factor 5; D039421:Integrin alpha2; C086559:growth differentiation factor 7; D016222:Fibroblast Growth Factor 2