Metallothionein 2A alleviates ulcerative colitis by inhibiting ferroptosis in intestinal epithelial cells with Tfrc downregulation

Background

Ferroptosis has emerged as a critical pathogenic mechanism in ulcerative colitis (UC). Metallothioneins (MTs), known for their redox regulatory functions, may protect against ferroptosis in UC. However, the underlying mechanisms are still unclear.

Methods

We conducted comprehensive investigations combining a bioinformatics analysis of a human UC dataset (GSE243625) with experimental validations using DSS-induced murine colitis models and RSL3-treated HCT116 human colon epithelial cells. Our experimental approaches included immunohistochemical analysis of MT2 expression, assessment of ferroptosis markers, evaluation of mitochondrial function, measurement of mitochondrial redox status and Fe²⁺, and profiling of protein expression. The therapeutic potential of ZnO nanoparticles was evaluated in vivo.

Results

Transcriptomic analysis revealed significant downregulation of all nine MT family members in UC patients, with the most pronounced suppression occurring in active disease. This finding was corroborated in murine models, which showed reduced colonic MT2 expression following DSS treatment. Cellular studies demonstrated that MT2A overexpression provides robust protection against RSL3-induced ferroptosis, evidenced by a reduction in lipid peroxidation, preservation of mitochondrial integrity, and decreased accumulation of mitochondrial reactive oxygen species. Mechanistically, MT2A modulated cellular iron homeostasis by downregulating transferrin receptor (Tfrc). Importantly, the oral administration of ZnO nanoparticles effectively restored MT2 expression, downregulated Tfrc, attenuated ferroptosis, and significantly alleviated colitis symptoms in vivo.

Conclusions

Our findings establish MT2A as a crucial regulator of ferroptosis in UC pathogenesis and identify ZnO nanoparticle-mediated MT2 induction and Tfrc downregulation as a promising therapeutic strategy. This study provides novel insights into the MT2A-ferroptosis axis and its potential translational applications for UC treatment.