Substrate Curvature Influences Cytoskeletal Rearrangement and Modulates Macrophage Phenotype

Abstract

Inflammation serves as a critical defense mechanism against pathogens and tissue damage but can lead to chronic diseases, such as cardiovascular disease and diabetes, when dysregulated. Macrophages play a pivotal role in orchestrating inflammatory responses, transitioning from pro-inflammatory M1 to anti-inflammatory M2 phenotypes to resolve inflammation and promote tissue repair. Current approaches to modulate macrophage phenotype predominantly rely on biochemical cues, which may induce systemic side effects. Given the mechanosensitivity of macrophages, this study investigates biophysical cues, specifically substrate curvature, as a localized strategy to regulate macrophage phenotype and minimize systemic repercussions. We hypothesized that substrate curvature influences macrophage immunophenotype by modulating F-actin polymerization. To test this hypothesis, we fabricated spherical microgels with tunable curvatures and characterized their biophysical properties. Our findings indicate that macrophages adhere to microgel surfaces irrespective of curvature, but the curvature significantly alters F-actin dynamics. Furthermore, manipulating cytoskeletal dynamics via selective actin inhibition partially reversed curvature-induced changes in macrophage phenotype. These results underscore the pivotal role of substrate curvature in modulating macrophage behavior and immunophenotype. Overall, our study demonstrates that substrate curvature significantly influences macrophage cytoskeletal dynamics and resulting immunophenotype. This simple approach can be utilized as a localized immunomodulatory treatment for inflammatory diseases.