Biomechanical Insights into the Proteomic Profiling of Cells in Response to Red Light Absorption

Photobiomodulation (PBM) is a promising non-invasive therapy for tissue repair, but its underlying cellular mechanisms are not fully understood. In this study, the biomechanical and proteomic responses of three cell types - keratinocytes (HACAT), fibroblasts (L929), and osteoblasts (OFCOLII) - exposed to red light (633 nm) are investigated using atomic force microscopy (AFM) and mass spectrometry-based proteomic analysis. Red light absorption resulted in cell-type-specific changes in viscoelastic properties, with fibroblasts exhibiting increased fluidity, reduced stiffness, and enhanced motility. Conversely, keratinocytes exhibited intensity-dependent responses, while osteoblasts appeared to be relatively insensitive to irradiation conditions. Proteomic profiling identified key signaling pathways involved in immune response, ATP production, and stress regulation. The immune and ATP pathways are strongly linked to the modulation of viscoelastic properties, particularly in fibroblasts, while weaker correlations were observed in keratinocytes. Cytoskeletal remodeling, primarily within the F-actin network, is identified as the main driver of mechanical alterations, with additional contributions from microtubules and intermediate filaments. These findings provide new insights into how red light absorption modulates cellular viscoelasticity through cytoskeletal remodeling, with potential applications in optimizing light-based therapies for tissue regeneration and disease treatment.