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.

Hyaluronan synthesis and degradation in cartilage and bone

“…Other studies show that HA released from rabbit growth plate chondrocytes during in vitro differentiation has a broad ranging 404 E. R. Bastow et al Synthesis and degradation of hyaluronan molecular mass [226]. Since hyal1 and hyal2 are expressed in the proliferative and hypertrophic zones of rabbit growth plate [227], these results suggest that HYALs, and synthases producing high M r HA, are active concurrently. Depolymerisation of HA by HYALs in growth plate cartilage will simultaneously depolymerise the HAaggrecan-link protein aggregates.…”

Expression and activity of hyaluronidases HYAL-1, HYAL-2 and HYAL-3 in the human intervertebral disc

“…Furthermore, future studies would ideally investigate NP and AF cells separately, although our own preliminary data on bovine NP and AF cells indicate marginal zonal differences in HYAL expression. Increased HYAL expression and/or activity have been described in numerous pathologies, such as during asthma (within the epithelium) [30], cartilage hypertrophy [52] or osteoarthritis and rheumatoid arthritis (within the knee synovium/synoviocytes) [53,54]. HYAL deficiency or knockdown/knockout have also been described to promote certain pathologies, leading, e.g., to swelling of the periarticular masses [55] as well as to progression of osteoarthritis [56,57].…”

Genetic effect of anatase on osteoblast‐like cells

“…HYAL3 which belongs to the Hyaluronan family, the major component of the extracellular matrix of cartilage, contributes to its structural and functional integrity. Tanimoto et al demonstrated that the selective expression of HYALs is essential for extracellular HA metabolism during chondrocyte differentiation 20…”

“…Tanimoto et al demonstrated that the selective expression of HYALs is essential for extracellular HA metabolism during chondrocyte differentiation. 20 Other genes related to the immune system are modulated. This mechanism could be related to the osseointegration process: indeed the inserted material has to be recognized as ''self'' by the immune system.…”