Six Hundred and Sixty Nanometer Light Exposure-Induced Alterations in Actin Filament, Mitochondrial Morphological Dynamics, and Migration in Mesenchymal Stem Cells.

Actin cytoskeleton alteration and cell homing/migration are crucial determinants for the success of stem cell (SC) based therapy. Photobiomodulation (PBM) is a promising non-pharmacological approach for modulating SC potency. Though ~660 nm is the most studied wavelength for the proliferation/differentiation of SCs, the migration and cytoskeleton remodeling aspects have not been investigated in detail. In this study, we report the effect of ~660 nm on actin filaments, mitochondrial morphological dynamics, along with the migration of human adipose-derived mesenchymal stem cells (hADMSCs). Exposure to ~660 nm (~15 J/cm²) elicits rapid actin fiber rearrangement leading to elongated, parallel fibers, and mitochondrial granulation along the leading edge of cell migration. In addition, 660 nm (~15 J/cm²) also enhances cell proliferation, ATP, and ROS levels. These ultrastructural and biochemical alterations, in conjunction with the increased cell migration, shed new light on mechanistic perspectives to elicit enhanced homing/migration in SCs and would help in further optimization of ~660 nm based SC priming.