Surfaceome analysis of extracellular vesicles from senescent cells uncovers uptake repressor DPP4

Senescent cells are beneficial for repairing acute tissue damage, but they are harmful when they accumulate in tissues, as occurs with advancing age. Senescence-associated extracellular vesicles (S-EVs) can mediate cell-to-cell communication and export intracellular content to the microenvironment of aging tissues. Here, we studied the uptake of EVs from senescent cells (S-EVs) relative to proliferating cells (P-EVs). Interestingly, P-EVs were readily taken up by other proliferating cells (fibroblasts and cervical cancer cells) while S-EVs were not; by contrast, macrophages selectively engulfed all EVs (P-EVs, S-EVs). We thus investigated the surface proteome (surfaceome) of P-EVs relative to S-EVs derived from cells that had reached senescence via replicative exhaustion, exposure to ionizing radiation, or treatment with etoposide. We discovered that relative to P-EVs, S-EVs from all senescence models were enriched in proteins DPP4, ANXA1, ANXA6, S10AB, AT1A1, and EPHB2. Among them, DPP4 was found to dictate selective uptake by proliferating cells, as ectopic overexpression of DPP4 in HeLa cells rendered DPP-expressing EVs that were no longer taken up by other proliferating cells. We propose that DPP4 on the surface of S-EVs makes these EVs refractory to internalization by proliferating cells, advancing our knowledge of the impact of senescent cells in aging-associated processes. We studied the uptake of EVs from senescent cells (S-EVs) relative to proliferating cells (P-EVs) and thus, we investigated the surface proteome (surfaceome) of P-EVs relative to S-EVs derived from cells that had reached senescence via replicative exhaustion, exposure to ionizing radiation, or treatment with etoposide.