ABSTRACT
Human acute-phase serum amyloid A (A-SAA) has been considered to be mainly synthesized by liver, however, recent studies have shown that human A-SAA is synthesized extrahepatically and is present in many tissues including inflammatory synovium. As the regulation of A-SAA synthesis by synovial cells (SC) and the physiological function(s) of A-SAA in the synovium remained unclear, the study was undertaken to clarify the control mechanism of A-SAA gene expression in SC, and the A-SAA function, i.e. whether A-SAA affected SC migration or not. SC were obtained by enzymatic digestion of synovial membrane from rheumatoid arthritis patients at the time of total knee replacement. The cultured SC were served for analysis of SAA1 (major A-SAA) mRNA expression using Northern blot analysis, for transcriptional regulation of SAA1 gene using luciferase reporter gene assay, and for SC migration assay. The PCR product amplified from SAA1.1 cDNA was used as a probe for Northern blot analysis.
