Role of the TLR4–NF-κB–FDX1 cuproptosis axis in mediating cognitive impairment associated with type 1 diabetes in children: an exploratory mechanistic study

This study explored how the TLR4-NF-κB-FDX1 cuproptosis axis contributes to type 1 diabetes (T1DM)-related cognitive impairment, seeking to uncover novel intervention targets. Key genes were screened from T1DM datasets via bioinformatics analysis. Primary hippocampal neurons, HBMECs, and a Transwell co-culture BBB model were established under high glucose plus copper overload. Cells received TLR4 inhibitor TAK-242 or FDX1 knockdown. A streptozotocin-induced T1DM mouse model was generated, followed by stereotaxic injection of TLR4-shRNA or FDX1-shRNA adenovirus. Cell viability, cuproptosis markers, BBB permeability, cognitive behaviors, and underlying mechanisms were assessed by CCK-8, ICP-MS, TEER, behavioral tests, Western blot, immunofluorescence, and ChIP-qPCR. FDX1 was markedly upregulated in T1DM and strongly correlated with TLR4/NF-κB. In vitro, high glucose plus copper overload activated the TLR4–NF-κB–FDX1 axis, induced DLAT lipoylation aggregation and cuproptosis, and caused neuronal synaptic injury along with disruption of endothelial tight junctions. Blocking TLR4 or knocking down FDX1 significantly attenuated these damages. In vivo, T1DM mice showed cognitive deficits and BBB disruption, both rescued by TLR4 or FDX1 knockdown. ChIP-qPCR confirmed that NF-κB bound directly to the FDX1 promoter to enhance its transcription. This study demonstrated for the first time that the TLR4–NF-κB–FDX1 cuproptosis axis plays a key pathological role in T1DM-related cognitive impairment, offering a new avenue for targeted therapy.