Fig. 1: Role of thiol peroxidases in the regulation of arterial tone in mice.

a Epimers of tryptophan-derived hydroperoxides cis-WOOH and trans-WOOH. b Schematic of proposed mechanism by which hydroperoxides antagonize arterial constriction in response to noradrenaline (NA). c Schematic representation of the thiol peroxidase redox cycles of peroxiredoxins (Prx), glutathione peroxidases (GPx), and their respective inhibitors auranofin (AUR) and (1,3-bis(2-chloroethyl)-1-nitrosourea, BCNU). d Compared with vehicle control (0.01% DMSO or EtOH), AUR (300 nM; left panel) and BCNU (100 μM; right panel) cause arterial relaxation of NA pre-constricted mesenteric resistance arteries from C57BL6/J mice (AUR n = 5, BCNU n = 4). Top panels show representative traces with respective dot blots shown below. e Comparison of relaxation responses from mice treated auranofin (AUR, 300 nM), BCNU (100 μM), and combined AUR and BCNU treatment (n = 7). f AUR-induced arterial relaxation in C57BL6/N PKG1α C42S mutant (n = 7; left panel) and BCNU-induced arterial relaxation in C57BL6/N PKG1α C42S mutant (n = 5; right panel) compared with PKG1α WT control mice (n = 5–8). g BCNU (100 μM; left panel) and AUR (300 nM; right panel) induced relaxation of NA pre-constricted arteries from naïve (BCNU n = 5, AUR n = 7) and lipopolysaccharide (LPS)-treated mice (BCNU n = 6, AUR n = 5). Representative traces and respective dot blots shown. h Hydrogen peroxide (H₂O₂) mediated relaxation of NA pre-constricted mesenteric resistance arteries from naïve (n = 4) and LPS-treated (n = 4) mice. Top shows representative traces with summary line chart shown below. i Redox state of Prx2, Prx4, and PKG1α in aorta and mesenteric arteries (mes) isolated from nave (n = 3) and LPS-treated (n = 3) mice. The oxidation state of Prx2, Prx4, and PKG1α was captured using N-ethylmaleimide and assessed by quantification of dimer and monomer bands. Red blood cells (RBCs) were used as positive controls for Prx2 dimer/monomer-to-total ratio. Top shows representative blots with respective dot blots shown below. Gray and black indicate control and experimental conditions, respectively. Vascular myography experiments were conducted in the presence of l-NAME (100 μM) and indomethacin (10 μM), with the scale bar depicting 0.5 mN (y-axis) and 2 min (x-axis). Summary data are shown as mean ± SEM, with each individual data point referring to an independent experiment. Statistical analysis was performed using two-tailed Mann–Whitney tests OR a one-way ANOVA with Holm–Sidak multiple comparison test (e). *p ≤ 0.05. Exact p-values are as follows: d p = 0.0286; e p = 0.0022 AUR+BCNU vs AUR; p = 0.0080, AUR+BCNU vs BCNU; f p = 0.0159 BCNU panel, p = 0.0034 AUR panel, g p = 0.0043 BCNU panel; 0.0087 AUR panel; h p > 0.9999, 1 μM; p = 0.9977, 3 μM; p = 0.5198, 10 μM; p = 0.2145, 30 μM; p = 0.8887; 100 μM: p = 0.5125, 300 μM. Uncropped blots and source data are provided as a Source data file.