Regulation of HAS expression in human synovial lining cells of TMJ by IL-1beta

Hyaluronan (HA), a major glycosaminoglycan of synovial fluid, is synthesised by a class of membrane-bound HA synthase (HAS) proteins. In the present study, we investigated the regulatory roles of IL-1beta on HAS gene expression and HA production by the fibroblastic synovial lining cells. The synovial lining cells from synovial membrane in human temporomandibular joint (TMJ) were cultured and characterised using immunocytochemistry with CD14, CD44, and vimentin monoclonal antibodies. With or without treatment with IL-1beta, the production of HA was detected with radiometric assay and the expression of HAS mRNAs were analysed with a semi-quantitative reverse transcribed polymerase chain reaction (RT-PCR). HA synthesis was significantly augmented with 1ng/ml of IL-1beta for both 24 and 48h stimulation, however the production of HA declined if stimulated with 10ng/ml of IL-1beta. The expression of HAS2 and 3 mRNA were enhanced about 4.2- and 7.2-fold after 4h stimulation with 1ng/ml of IL-1beta, respectively. From these results, it is concluded that IL-1beta functions on regulating HAS expression and consequently promoting the secretion of HA in synovial lining cells from TMJ.