title: Hyaluronidase expression in cultured growth plate chondrocytes during differentiation.
abstract: Hyaluronan (HA) is a major component of the extracellular matrix of cartilage, contributes to its structural and functional integrity, and has various important roles in the differentiation of chondrocytes. HA metabolism is regulated by both anabolic and catabolic processes; however, the details have not yet been clarified. The purpose of this study was to clarify the expression patterns of hyaluronidase (HAase) mRNAs (from the relevant HAase genes: the HYALs) and HAase activity during chondrocyte differentiation. Cartilage tissue and growth plate chondrocytes were isolated from the ribs of 4-week-old male Japanese rabbits. The expression of HYAL mRNAs in cartilage was analyzed by in situ hybridization. The expression levels of HYAL mRNAs in the culture were analyzed for each of the chondrocyte differentiation stages by means of quantitative real-time polymerase chain reaction analysis. Enzymatic activity in the conditioned medium from the cultures was examined by using HA zymography and an enzyme-linked immunosorbent-like assay. The expression levels of HYAL1 and HYAL2 mRNAs were enhanced about 2.8-fold and 3.2-fold at the maximum during the early matrix forming stage, respectively, and by about 3.2-fold and 2.0-fold at the maximum in the hypertrophic stage, respectively. HYAL3 mRNA was not detected throughout the experimental period. HAase activity was enhanced at the early matrix forming and hypertrophic stages. These results suggest that selective expression of HYALs is essential for extracellular HA metabolism during chondrocyte differentiation.
authors.affiliation: Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan. tkotaro@hiroshima-u.ac.jp
authors.forename: Kotaro
authors.initials: K
authors.lastname: Tanimoto
authors.forename: Aya
authors.initials: A
authors.lastname: Suzuki
authors.forename: Shigeru
authors.initials: S
authors.lastname: Ohno
authors.forename: Koubun
authors.initials: K
authors.lastname: Honda
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Tanaka
authors.forename: Takeyoshi
authors.initials: T
authors.lastname: Doi
authors.forename: Maiko
authors.initials: M
authors.lastname: Nakahara-Ohno
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Yoneno
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nakatani
authors.forename: Masashi
authors.initials: M
authors.lastname: Ueki
authors.forename: Tamami
authors.initials: T
authors.lastname: Yanagida
authors.forename: Reiko
authors.initials: R
authors.lastname: Kitamura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tanne
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000201:enzymology; D017077:Culture Media, Conditioned / Q000737:chemistry / Q000378:metabolism; D005109:Extracellular Matrix / Q000201:enzymology*; D006132:Growth Plate / Q000166:cytology* / Q000201:enzymology; D006821:Hyaluronoglucosaminidase / Q000235:genetics / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits
chemical_list: D017077:Culture Media, Conditioned; D012333:RNA, Messenger; D006821:Hyaluronoglucosaminidase