[MPV17 inhibits iron overload-induced ferroptosis of splenic CD3⁺ T cells in mice by blocking ERK pathway]

Objective This work aimed to explore the effect of iron overload on splenic injury and the role of MPV17 in the ferroptosis of splenic CD3⁺ T cells from mice subjected to iron overload. Methods Mice were randomly divided into normal diet group, high-iron diet group, high-iron diet combined with Fer-1 treatment group, and high-iron diet combined with adenovirus harboring MPV17 injection group, with 5 mice in each group. After treatment for 8 weeks, mice spleens were harvested and fixed; Histological section and HE staining were performed to observe the structures of the spleens; Cell death of CD3⁺ T cells was detected by propidium iodide (PI) staining; The lipid peroxidation levels were detected by C11 BODIPY581/591 staining; The mRNA levels of Solute carrier family 7 member 11 (SLC7A11) and prostaglandin-endoperoxide synthase 2 (PTGS2) were detected by qPCR assays; The macrophage phenotype-switching (M1/M2) were detected by flow cytometry; The levels of TNF-α, IL-1β and IL-6 were measured by ELISA assays. Moreover, high-iron diet combined with extracellular signal-regulated kinase (ERK) inhibitor treatment group, ERK agonist treatment group, β-gal combined with ERK agonist treatment group, and MPV17 overexpression combined with ERK agonist treatment group were added. The protein levels of MPV17, glutathione peroxidase 4 (GPX4) and phosphorylated ERK (p-ERK) were detected by Western blot; The mitochondrial membrane potential was detected by JC-1 staining and flow cytometry. Results Compared with the normal diet group, the red pulps of the mice spleens from the high-iron diet group showed irregular structures and the white pulps were almost missing; Cell death, lipid peroxides, and the expression levels of SLC7A11 and PTGS2 increased; Both the ratio of M1 macrophages to M2 macrophages and the levels of inflammatory factors increased. Fer-1 treatment or overexpression of MPV17 in the high-iron diet mice group partially recovered the irregular structures of the spleens, reduced cell death and lipid peroxides in CD3⁺ T cells, and decreased the expression levels of SLC7A11 and PTGS2; The ratio of M1/M2 macrophages and the levels of inflammatory factors were decreased. High-iron diet decreased the protein levels of GPX4 while p-ERK were up-regulated. Inhibition of ERK partially recovered the protein levels of GPX4; ERK agonist decreased the protein levels of GPX4; MPV17 inhibited the ERK signaling and partially recovered the protein levels of GPX4 and the decreased mitochondrial membrane potential of CD3⁺ T induced by ERK activation. Conclusion Iron overload resulted in splenic injury and ferroptosis in the splenic CD3⁺ T cells; MPV17 prevented splenic injury and ferroptosis of splenic CD3⁺ T cells of the iron overload mice through blocking ERK signaling pathway.