THE FPR2-MEDIATED MICROGLIA ACTIVATION MODULATES MORPHOLOGY AND BIOMECHANICAL PROPERTIES DURING INFLAMMATION

Microglia are the primary resident immune cells of the central nervous system. Recently, extensive evidence suggests that microglia play a key role in the inflammatory response by dynamically adapting their phenotypes to various environmental cues. The resolution of inflammation (ROI) is an active process mediated by specialized pro-resolving molecules acting via the N-formyl peptide receptor 2 (FPR2). In contrast, unresolved neuroinflammation is a major contributor to neurodegenerative disorders, including Alzheimer’s disease (AD). So far, the impact of FPR2-mediated activation on microglial morphology and biomechanical properties remains poorly understood. To address this gap, we combined high-content imaging (Operetta) with atomic force microscopy (AFM) and enzyme-linked immunosorbent assay (ELISA) to analyze changes in microglial morphology, cytoskeletal organization, biomechanical properties, and cytokine profiles. This approach, for the first time, allows comprehensive profiling of microglial structural and mechanical changes during FPR2-driven inflammatory resolution. Primary murine microglia were isolated from pups of knock-in AD (APP^NL-F/NL-F, KI) and wild-type mice (C57BL/6, WT). Cells were treated with new ureidopropanamide FPR2 agonists and/or lipopolysaccharide (LPS). LPS induced morphological remodeling, reduced cell deformability, and elevated pro-inflammatory cytokines in both KI and WT animals. Importantly, FPR2 agonists modulated morphology, F-actin organization, improved biomechanical properties, and shifted cytokine production toward a pro-resolving state. Our data suggest that changes in cytoskeletal organization, morphology, and biomechanics may serve as novel quantitative indicators of ROI supporting FPR2 as a potential target in AD.
Supported by the grant no. 2021/43/B/NZ4/01133, National Science Centre, Poland (Tasks 2 and 3).