Fig 2: Indices of oxidative stress measured from circulating ELVs prior to and in response to acute maximal treadmill exercise. Repeated measures analysis of variance analysis demonstrated a differential impact of acute maximal treadmill exercise on GSH (panel A) and LPO (panel B) concentrations measured from circulating ELVs across the NW-Tr, NW-Utr, and Ob-UTr participant groups, whereas PC concentrations from plasma ELV responded similarly across all participant groups (panel C). Acute maximal treadmill exercise exhibited no impact on ELV total ROS/RNS (panel D), TAC (panel E), NRF2 (panel F), or SOD3 (panel G) expression. Data are presented as means ± S.D. and are normalized by Ponceau S solution (NRF2 and SOD3). The * indicates a significant difference compared to NW-Tr participants; # indicates a significant difference compared to NW-Utr participants; § indicates a significant difference compared to pre-exercise values (p ≤ 0.05). Abbreviations: ELV: exosome-like extracellular vesicles; GSH: glutathione; LPO: lipid peroxidation; NRF2: nuclear factor erythroid 2-related factor 2; NW-Tr: individuals with normal weight who are aerobically trained; NW-UTr: individuals with normal weight who are aerobically untrained; Ob-UTr: individuals with obesity who are aerobically untrained; PC: protein carbonyl; ROS/RNS: reactive oxygen/nitrogen species; SOD3: superoxide dismutase 3; TAC: total antioxidant capacity. The uncropped western blot figures were presented in Figure S1.

Fig 3: Effects of borax treatment on gene expression and protein levels of HSPA5, NRF2 and GPx4 in U251 and A172 cells. (A) HPSA5 mRNA levels in U251 cells; (B) HSPA5 mRNA levels in A172 cells; (C) NRF2 mRNA levels in U251 cells; (D) NRF2 mRNA levels in A172 cells; (E) GPx4 mRNA levels in U251 cells; (F) GPx4 mRNA levels in A172 cells; (G) relative protein levels. All experiments were performed in triplicate repetitions in three independent experiments.*p < 0.05, **p < 0.01 and ***p < 0.001 versus control group.

Fig 4: Borax treatment regulated HSPA5, NRF2, MDA, GSH and GPx4 levels in U251 and A172 cells. (A) HSPA5 levels in U251 cells; (B) HSPA5 levels in A172 cells; (C) NRF2 levels in U251 cells; (D) NRF2 levels in A172 cells; (E) MDA levels in U251 cells; (F) MDA levels in A172 cells; (G) GSH levels in U251 cells; (H) GSH levels in A172 cells; (I) GPx4 levels in U251 cells; (J) GPx4 levels in A172 cells. All experiments were performed in triplicate repetitions in three independent experiments. *p < 0.05, **p < 0.001 and ***p < 0.0001 versus control group.

Fig 5: Proportion of plasma relative to total circulating oxidative stress concentrations (plasma plus ELV) prior to and in response to acute maximal treadmill exercise. Repeated measures analysis of variance analysis demonstrated a differential impact of acute maximal treadmill exercise on the ratios of GSH (panel A), PC (panel C), and TAC (panel E) in Ob-UTr compared to NW-Tr and NW-Utr participants, whereas the ratio of total ROS/RNS was similar between participant groups (panel D). Acute maximal treadmill exercise exhibited no impact on the ratio LPO (panel B), NRF2 (panel F), or SOD3 (panel G) across participant groups. Data are presented as means ± S.D. * indicates a significant difference compared to NW-Tr participants; # indicates a significant difference compared to NW-Utr participants; § indicates a significant difference compared to pre-exercise values (p ≤ 0.05). Abbreviations: ELV: exosome-like extracellular vesicles; GSH: glutathione; LPO: lipid peroxidation; NRF2: nuclear factor erythroid 2-related factor 2; NW-Tr: individuals with normal weight who are aerobically trained; NW-UTr: individuals with normal weight who are aerobically untrained; Ob-UTr: individuals with obesity who are aerobically untrained; PC: protein carbonyl; ROS/RNS: reactive oxygen/nitrogen species; SOD3: superoxide dismutase 3; TAC: total antioxidant capacity.