Alpha, mu and pi class glutathione S-transferases in human synovium and cultured synovial fibroblasts: effects of interleukin-1 alpha, hydrogen peroxide and inhibition of eicosanoid synthesis.

We describe expression of alpha, mu and pi class glutathione S-transferase (GST) and, CuZn- and Mn superoxide dismutase (SOD) in human synovium and cultured synovial fibroblasts. Immunohistochemical and immunoblotting studies showed synovium and cultured cells expressed pi GST and both isoforms of SOD. Cellular localisation was largely perinuclear. No expression of alpha or mu GST was detected even though polymerase chain reaction analysis showed 4/6 subjects had positive genotypes at the polymorphic, mu class GSTM1 locus. Incubation of cultured synovial fibroblasts with H2O2, IL-1 alpha and the cyclooxygenase and lipoxygenase inhibitor, Tenidap, did not induce expression of alpha, mu or pi GST though treatment with IL-1 alpha caused a marked increase in the expression of Mn SOD.