Mina Sohrabi (Berlin, DE), Dr. Erik Brauer (Berlin, DE), Dr. Aaron Xerach Herrera Martin (Berlin, DE), Prof. Dr. Ansgar Petersen (Berlin, DE)
Abstract text (incl. figure legends and references)
Cellular senescence is an irreversible stress program associated with aging and various biological processes. Despite the growing interest into its role in normal and pathological tissue repair, particularly in aged individuals, the mechano-response of senescent cells to physical cues of the microenvironment remains elusive. We here investigate the impact of senescence on cellular response to substrate stiffness and curvature and link these findings to key processes of tissue regeneration. Senescence was induced in human dermal fibroblasts through serial passaging (replicative senescence), DNA damage induction using Mitomycin C, and inducible over-expression of p16Ink4a. The senescence phenotype was confirmed by cell-cycle arrest, DNA damage response markers, and increased lysosomal mass indicated by senescence-associated beta-galactosidase staining. Cells were cultured on soft (1.7kPa) and stiff (48.3kPa) collagen-coated polyacrylamide gels, and tissue culture plastic (TCP). Immunofluorescence imaging of senescent cells revealed pronounced changes in cell spreading and actin re-arrangement towards stiff substrates, suggesting enhanced sensitivity to mechanical cues (ie. superphysiologically stiff TCP). Alterations in cytoskeletal organization in senescent cells correlated with changes in focal adhesion assembly, which were also influenced by stiffness across all groups. When cultured on topographic substrates with different principle meso-scale geometries, senescent cells showed clear differences in organization in response to the local 3D curvature. This included alterations in cell orientation and spanning across concave structures being of relevance for tissue formation. Together our findings shed light on the so far unknown interaction between senescent cells and their physical environment. This could potentially help in the prediction of their response in physiological and pathological tissue repair.