Effects of anti-rheumatic gold salts on NF-κB mobilization and tumour necrosis factor-alpha (TNF-α)-induced neutrophil-dependent cytotoxicity for human endothelial cells

We have previously shown that the gold-containing disease-modifying anti-rheumatic drugs, auranofin (AF) and gold sodium aurothiomalate (GSTM) reduce human umbilical vein endothelial cell (HUVEC) adhesion molecule expression and neutrophil (PMN) adherence. AF diminishes E-selectin and intercellular adhesion molecule-1 (ICAM-1) on cytokine-activated HUVEC, while GSTM decreases only E-selectin. Since tight adhesion is critical for PMN to damage EC, we tested whether these drugs modulated human PMN-mediated injury to TNF-α-activated HUVEC in vitro (as measured by ⁵¹Cr release). Here we show that TNF-α caused a prominent PMN-mediated cytotoxicity that was dose- dependently reduced when AF and GSTM were added to the assay system. We also found that a potent inhibitor of NF-κB, pyrrolidine dithiocarbamate (PDTC) in a dose-dependent manner impaired TNF-α-induced cytotoxicity, indicating a role of NF-κB activation in cytokine-induced endothelial injury. To examine the effects of AF and GSTM on TNF-α-induced NF-κB activation this was measured in HUVEC nuclear extracts by an electrophoretic mobility shift assay. AF, but not GSTM, decreased TNFα-induced NF-κB activation in HUVEC. Thus, in this in vitro model of vasculitis, AF and GSTM dose dependently reduced TNF-α-mediated neutrophil-dependent cytotoxicity for HUVEC, and AF, but not GSTM, inhibited NF-κB mobilization, thereby providing possible mechanisms for effects of AF and GSTM.