Fig 1: Tst−/− mice brain cortexes display a dysregulated GSH pathway. A–D: Data are expressed as mean ± SD, student T test. (A) Tst mRNA and Tst protein levels of Tst−/− (red) and C57BL/6J (black) mice (n = 4). (B) Thiosulfate content in C57BL/6J mice (Black, n = 3) and Tst−/− mice brain cortexes (Red, n = 4) measured by HPLC-MS/MS. H2S and H2Sn concentrations were measured using fluorescent probes, and show that H2S decreased 5% and H2Sn increased 5% in the Tst−/−(red) compared with C57BL/6J mice (black) (n = 4). (C) GSH and GSSG contents in mice cortexes in the presence (black) or absence (red) of TST (n = 4). (D) Quantification of immunoblots of cerebral cortical area for GPX4 protein level in Tst−/−(red) compared with C57BL/6J mice (black) (n = 3). The original blotting picture is shown in Fig. S1F. (E) Brief schematic showing H2S enzymatic pathway. Sulfide is an endogenously produced gaseous signaling molecule via CBS, CSE and MPST. Polysulfides (H2Sn) became novel reactive sulfur species, which is derived from H2S with MPST. TST converts thiosulfate produced via non-enzymatic reactions to sulphite. Then oxidation of sulphite to sulfate is dependent on the glutathione system. GPX4 and GR is the cofactor of conversion between GSH and GSSG. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)