title: Focal Adhesion Assembly Induces Phenotypic Changes and Dedifferentiation in Chondrocytes.
abstract: The expansion of autologous chondrocytes in vitro is used to generate sufficient populations for cell-based therapies. However, during monolayer culture, chondrocytes lose inherent characteristics and shift to fibroblast-like cells as passage number increase. Here, we investigated passage-dependent changes in cellular physiology, including cellular morphology, motility, and gene and protein expression, as well as the role of focal adhesion and cytoskeletal regulation in the dedifferentiation process. We found that the gene and protein expression levels of both the focal adhesion complex and small Rho GTPases are upregulated with increasing passage number and are closely linked to chondrocyte dedifferentiation. The inhibition of focal adhesion kinase (FAK) but not small Rho GTPases induced the loss of fibroblastic traits and the recovery of collagen type II, aggrecan, and SOX9 expression levels in dedifferentiated chondrocytes. Based on these findings, we propose a strategy to suppress chondrogenic dedifferentiation by inhibiting the identified FAK or Src pathways while maintaining the expansion capability of chondrocytes in a 2D environment. These results highlight a potential therapeutic target for the treatment of skeletal diseases and the generation of cartilage in tissue-engineering approaches. J. Cell. Physiol. 231: 1822-1831, 2016. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Division of Mechanical Engineering, School of Mechanical, Aerospace, and Systems Engineering, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Republic of Korea.
authors.forename: Hyunjun
authors.initials: H
authors.lastname: Shin
authors.affiliation: Division of Mechanical Engineering, School of Mechanical, Aerospace, and Systems Engineering, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Republic of Korea.
authors.forename: Mi Nam
authors.initials: MN
authors.lastname: Lee
authors.affiliation: Division of Mechanical Engineering, School of Mechanical, Aerospace, and Systems Engineering, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Republic of Korea.
authors.forename: Jin Seung
authors.initials: JS
authors.lastname: Choung
authors.affiliation: Department of Mechanical Systems Engineering, Hansung University, Seoul, Republic of Korea.
authors.forename: Sanghee
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Biomedical Sciences, Inha University College of Medicine, Jung-gu, Incheon, Republic of Korea.
authors.forename: Byung Hyune
authors.initials: BH
authors.lastname: Choi
authors.affiliation: Natural Products Research Institute, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul, Republic of Korea.
authors.forename: Minsoo
authors.initials: M
authors.lastname: Noh
authors.affiliation: Division of Mechanical Engineering, School of Mechanical, Aerospace, and Systems Engineering, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Republic of Korea.
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: Shin
mesh_terms: D053674:Aggrecans / Q000378:metabolism; D000818:Animals; D054337:Cell Dedifferentiation / Q000187:drug effects; D049109:Cell Proliferation; D048430:Cell Shape; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D020219:Chondrogenesis / Q000187:drug effects; D024043:Collagen Type II / Q000378:metabolism; D051417:Focal Adhesion Kinase 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D022001:Focal Adhesions / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D008297:Male; D010641:Phenotype; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D017207:Rats, Sprague-Dawley; D055758:SOX9 Transcription Factor / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D020741:rho GTP-Binding Proteins / Q000378:metabolism; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D053674:Aggrecans; D024043:Collagen Type II; D047428:Protein Kinase Inhibitors; D055758:SOX9 Transcription Factor; D051417:Focal Adhesion Kinase 1; C496052:Ptk2 protein, rat; D019061:src-Family Kinases; D020741:rho GTP-Binding Proteins