title: Kruppel-like factor 5 causes cartilage degradation through transactivation of matrix metalloproteinase 9.
abstract: Although degradation of cartilage matrix has been suggested to be a rate-limiting step for endochondral ossification during skeletal development, little is known about the transcriptional regulation. This study investigated the involvement of KLF5 (Krüppel-like factor 5), an Sp/KLF family member, in the skeletal development. KLF5 was expressed in chondrocytes and osteoblasts but not in osteoclasts. The heterozygous deficient (KLF5+/-) mice exhibited skeletal growth retardation in the perinatal period. Although chondrocyte proliferation and differentiation were normal, cartilage matrix degradation was impaired in KLF5+/- mice, causing delay in replacement of cartilage with bone at the primary ossification center in the embryonic limbs and elongation of hypertrophic chondrocyte layer in the neonatal growth plates. Microarray analyses identified MMP9 (matrix metalloproteinase 9) as a transcriptional target, since it was strongly up-regulated by adenoviral transfection of KLF5 in chondrogenic cell line OUMS27. The KLF5 overexpression caused gelatin degradation by stimulating promoter activity of MMP9 without affecting chondrocyte differentiation or vascular endothelial growth factor expression in the culture of chondrogenic cells; however, in osteoclast precursors, it affected neither MMP9 expression nor osteoclastic differentiation. KLF5 dysfunction by genetic heterodeficiency or RNA interference was confirmed to cause reduction of MMP9 expression in cultured chondrogenic cells. MMP9 expression was decreased in the limbs of KLF5+/- embryos, which was correlated with suppression of matrix degradation, calcification, and vascularization. We conclude that KLF5 causes cartilage matrix degradation through transcriptional induction of MMP9, providing the first evidence that transcriptional regulation of a proteinase contributes to endochondral ossification and skeletal development.
authors.affiliation: Sensory and Motor System Medicine, University of Tokyo, Tokyo 113-8655, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Shinoda
authors.forename: Naoshi
authors.initials: N
authors.lastname: Ogata
authors.forename: Akiro
authors.initials: A
authors.lastname: Higashikawa
authors.forename: Ichiro
authors.initials: I
authors.lastname: Manabe
authors.forename: Takayuki
authors.initials: T
authors.lastname: Shindo
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamada
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Kugimiya
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ikeda
authors.forename: Naohiro
authors.initials: N
authors.lastname: Kawamura
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kawasaki
authors.forename: Kensuke
authors.initials: K
authors.lastname: Tsushima
authors.forename: Norifumi
authors.initials: N
authors.lastname: Takeda
authors.forename: Ryozo
authors.initials: R
authors.lastname: Nagai
authors.forename: Kazuto
authors.initials: K
authors.lastname: Hoshi
authors.forename: Kozo
authors.initials: K
authors.lastname: Nakamura
authors.forename: Ung-il
authors.initials: UI
authors.lastname: Chung
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawaguchi
mesh_terms: D000818:Animals; D002356:Cartilage / Q000166:cytology / Q000196:embryology*; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D049109:Cell Proliferation; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism*; D005109:Extracellular Matrix / Q000235:genetics / Q000378:metabolism; D005121:Extremities / Q000196:embryology; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D009928:Organ Specificity / Q000502:physiology; D010012:Osteogenesis / Q000502:physiology*; D011401:Promoter Regions, Genetic / Q000502:physiology; D034622:RNA Interference; D014158:Transcription, Genetic; D015533:Transcriptional Activation / Q000502:physiology*
chemical_list: C492214:KLF5 protein, human; C118391:Klf5 protein, mouse; D051741:Kruppel-Like Transcription Factors; D020780:Matrix Metalloproteinase 9; C501830:Mmp9 protein, mouse