Inflammatory Burden Shapes Antioxidant Adaptation and Immunometabolic Remodeling in LPS-Activated BV-2 Microglial Cells

Neuroinflammation is a hallmark of numerous neurodegenerative diseases and is characterized by profound inflammatory, metabolic, and redox alterations in activated microglia. Although lipopolysaccharide (LPS)-stimulated BV-2 cells represent one of the most widely used in vitro models of neuroinflammation, a comprehensive understanding of the coordinated molecular adaptations underlying this model remains incomplete. The aim of this study was to characterize the proteomic remodeling of BV-2 cells exposed to LPS 100 ng/mL for 24 h and investigate the relationship between antioxidant and inflammatory responses across increasing levels of LPS exposure. Proteomic analysis identified 89 differentially expressed proteins involved in cytoskeletal organization, clathrin-mediated endocytosis, lysosomal function, immunometabolism, and redox regulation. Validation experiments confirmed changes in cytoskeletal and endocytic proteins, including Vimentin, Gelsolin, Disabled homolog-2, and clathrin light chain A, together with modulation of proteins involved in the lysosomal pathways and marked induction of the immunometabolic enzyme aconitate decarboxylase 1. Functional enrichment analysis identified Nuclear factor erythroid 2-related factor 2 (NRF2) as the most significantly activated upstream regulator, a prediction consistent with engagement of an adaptive antioxidant program. Interestingly, analysis of increasing LPS concentrations revealed that antioxidant responses were not proportional to the inflammatory stimulus. Expression of NRF2-controlled antioxidant enzymes progressively increased for LPS concentrations up to 500 ng/mL, but declined at 1000 ng/mL LPS, whereas pro-inflammatory mediators remained continuously upregulated. This pattern is consistent with the attenuation of antioxidant adaptation under the highest inflammatory burden tested. Together, these findings demonstrate that the BV-2/LPS model is characterized by a dynamic interplay between inflammatory, redox, metabolic, lysosomal, endocytic, and cytoskeletal pathways, providing a more comprehensive characterization to support the interpretation and experimental use of this neuroinflammatory model.