title: In vitro expansion of human nasoseptal chondrocytes reveals distinct expression profiles of G1 cell cycle inhibitors for replicative, quiescent, and senescent culture stages.
abstract: In vitro expansion of chondrocytes for tissue-engineering applications is limited by forms of growth arrest known as quiescence and replicative senescence. At the molecular level cyclin-dependent kinase inhibitors (CDKIs) are involved in mediating growth arrest in the G1 phase of the cell cycle. Using ribonuclease protection assays and immunocytochemical staining methods, we quantitatively analyzed expression profiles of G1 cell cycle inhibitors at the mRNA and protein levels. These inhibitors included the CDKIs of the CIP/KIP family (p21CIP1 p27KIP1, and p57KIP2) and the INK4 family (p15INK4b, p16INK4a, p18INK4c, and p19INK4d) as well as the retinoblastoma protein-family (pRb, p107, and p130) and the tumor suppressor p53. Analysis was carried out in proliferating, quiescent, and senescent states of primary cultures of adult human nasoseptal chondrocytes. The most pronounced effect (p < 0.0001) between cultures in proliferation and cultures in growth arrest was an increased expression of the CDKIs p57KIP2 and p15INK4b for quiescent growth arrest, and of p16INK4a, p15INK4b, and p57KIP2 for senescent growth arrest. Thus, these cell cycle inhibitors represent potential candidates for selective intervention to promote cellular multiplication of chondrocytes undergoing in vitro expansion for tissue-engineering applications. Possible methods of modulation include the targeted elimination of specifically identified cell cycle inhibitors by antisense technologies.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Hearing Research Center Tübingen, University of Tübingen Medical Center, Tübingen, Germany. hubert.loewenheim@uni-tuebingen.de
authors.forename: Hubert
authors.initials: H
authors.lastname: Löwenheim
authors.forename: Joachim
authors.initials: J
authors.lastname: Reichl
authors.forename: Harald
authors.initials: H
authors.lastname: Winter
authors.forename: Hartmut
authors.initials: H
authors.lastname: Hahn
authors.forename: Christian
authors.initials: C
authors.lastname: Simon
authors.forename: Karina
authors.initials: K
authors.lastname: Gültig
authors.forename: Andrea
authors.initials: A
authors.lastname: Müller
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Zenner
authors.forename: Ulrike
authors.initials: U
authors.lastname: Zimmermann
authors.forename: Marlies
authors.initials: M
authors.lastname: Knipper
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000166:cytology; D049109:Cell Proliferation; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000502:physiology*; D019902:Chondrocytes / Q000166:cytology*; D016193:G1 Phase; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D007700:Kinetics; D009300:Nasal Septum / Q000166:cytology*; D012333:RNA, Messenger / Q000378:metabolism; D016196:S Phase; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D012333:RNA, Messenger