GPX6 and arthritic joint disease: However, following arthritis induction, the hepatic glutathione pathway genes glutathione peroxidase 6 (GPX6), glutathione S-transferase Mu 2 (GSTM2), and GSTM6 were upregulated in PON1Tg but not in WT mice compared to non-arthritic controls (Supplementary Fig. 1), These data were similar to our initial RNA sequencing analyses.