Reversible Mechano-Regulation of Cellular Senescence: Effects of Substrate Stiffness on Cells.

Aging involves the accumulation of molecular alterations within cells and the extracellular matrix, resulting in cellular senescence and declining physiological functions. This study investigates the correlation between the biophysical environment and cellular aging, specifically examining how mechanical and biochemical cues affect cellular senescence and tissue degeneration. Cells were cultured on acrylamide hydrogels of different stiffnesses (4 and 19 kPa), and their mechanical properties were characterized by measuring Young's modulus via compression tests. Cell proliferation, morphology, gene and protein expression, and autophagy activity were assessed using multiple assays and imaging techniques. Cells cultured on stiff hydrogels exhibited elongated morphologies, whereas cells on soft hydrogels formed spherical clusters. Notably, longevity-associated genes were upregulated in cells cultured on softer substrates. Reversibility experiments demonstrated that the aging phenotype could be reversed by modulating mechanical culture conditions, with softer environments enhancing autophagic activity. In summary, hydrogel stiffness significantly impacts aging-related cellular behavior. These findings suggest biomechanical cues as a promising strategy to promote cellular rejuvenation and combat aging.