Optimizing Photobiomodulation for Smooth Muscle Differentiation of Adipose-Derived Stem Cells Using Retinoic Acid and TGFβ in a Two-Dimensional Model

Smooth muscle (SM) dysfunction contributes to several pathological conditions, including atherosclerosis; current treatment strategies often fail to restore functional contractility. Adipose-derived stem cells (ADSCs) offer a promising cell source for regenerative medicine due to their accessibility and multipotency. Their differentiation into smooth muscle cells (SMC) is commonly driven by biochemical cues such as retinoic acid and transforming growth factor β; however, supporting this process with additional, non-invasive stimuli may enhance outcomes. Photobiomodulation (PBM) has emerged as a potential modulator of cellular metabolism, mitochondrial function and lineage commitment; however, its role in ADSCs to SMC differentiation remains insufficiently defined. ADSCs were irradiated with green (525 nm), near-infrared (825 nm) or dual wavelengths at 5 J/cm2 and 10 J/cm2 alongside the growth factors. Proliferation, cytotoxicity, mitochondrial membrane potential, collagen production, migration and smooth muscle marker expression were assessed. PBM induced a fluence-dependent biphasic response. 5 J/cm2 fluences enhanced proliferation, mitochondrial activity, collagen deposition and organized SMC marker expression, whereas 10 J/cm2 fluences lowered proliferation and membrane potential, reduced collagen and increased migration. PBM at 5 J/cm2, especially greenlight, most effectively promoted ADSCs’ progression towards a SMC-like phenotype, with features consistent with a more contractile-like state.