NFE2L2 suppresses microglia-mediated neuroinflammation to preserve neuronal dendritic architecture from cadmium-induced damage

Cadmium (Cd), a widespread environmental toxic metal, is linked to central nervous system dysfunction and neuronal structural damage, yet its mechanisms remain unclear. This study combined network toxicology with experimental validation to explore how Cd impairs dendritic integrity through neuroinflammatory pathways. Network analysis suggested that Cd-induced dendritic injury was likely mediated by inflammatory signaling pathways, with nuclear factor-erythroid 2-related factor 2 (Nfe2l2), a major redox regulator, highlighted as a candidate regulator. Therefore, we investigated the involvement of microglia-mediated neuroinflammation in Cd-induced dendritic damage and assessed the role of Nfe2l2 in this process, using Nfe2l2 knockout mice and Nfe2l2 knockdown BV2 microglia. Furthermore, primary neurons were co-cultured with conditioned media (CM) from Cd-treated microglia to evaluate how Nfe2l2-regulated neuroinflammation contributes to dendritic damage. Nfe2l2 deficiency aggravated Cd-induced dendritic damage in the hippocampus, manifested as significant reductions in dendritic length, intersections, and branch points. In parallel, Nfe2l2 deficiency also intensified Cd-induced microglial activation and neuroinflammation in the hippocampus. Consistently, Nfe2l2 knockdown amplified Cd-induced BV2 microglial activation, characterized by increased migratory and phagocytic activity, and the subsequent cytokine release. Subsequently, CM derived from these activated microglia further exacerbated neuronal dendritic damage. Moreover, Nfe2l2 knockdown diminished minocycline's anti-inflammatory and neuroprotective effects. These results demonstrate that Cd-induced microglial activation and inflammation are central to dendritic injury, and that Nfe2l2 is essential in protecting neurons from Cd-driven neuroinflammation.