Objective:

To investigate the specific mechanism by which cuproptosis contributes to the pathogenesis of neuromyelitis optica spectrum disorder (NMOSD).

Background:

Our previous study (Liu et al. Sci Adv, 2025) suggested the potential of cuproptosis-related genes in predicting NMOSD relapse, yet the underlying mechanism remains unclear.

Design/Methods:

Peripheral blood samples were collected from NMOSD patients during acute and remission phases, and from healthy controls. PBMCs were isolated via Ficoll density gradient centrifugation. Naïve CD4+ T cells were purified using immunomagnetic beads. Single-cell RNA sequencing was performed, and data were analyzed with Seurat. Intracellular copper concentrations were quantified by a copper assay kit and LC-MS. Protein expression of the key cuproptosis regulator FDX1 was assessed by Western Blot. Naïve CD4+ T cells from healthy donors were cultured under pro-inflammatory (Th17/Tfh) polarizing conditions with or without the copper chelator tetrathiomolybdate (TTM). Final cell phenotypes were determined by flow cytometry.

Results:

Add Module Score analysis revealed a significant enrichment of cuproptosis-related genes in naïve CD4+ T cells from acute-phase NMOSD patients compared to both remission-phase patients and healthy controls. Consistently, these cells exhibited significantly elevated intracellular copper levels and FDX1 protein expression. In vitro, when healthy naïve CD4+ T cells were driven toward pro-inflammatory (Th17/Tfh) lineages, their endogenous copper and FDX1 levels increased. Crucially, copper chelation with TTM during polarization significantly reduced the generation of these pro-inflammatory T helper subsets.

Conclusions:

Our findings suggest that cuproptosis promotes NMOSD pathogenesis by driving the aberrant differentiation of naïve CD4+ T cells toward pro-inflammatory T helper cells. Targeting this pathway may represent a novel therapeutic strategy.