SILAC Analysis Reveals a Role for the Senescence-Associated Secretory Phenotype in Hemostasis

Cellular senescence irreversibly arrests cell proliferation, accompanied by a multi-component senescence-associated secretory phenotype (SASP) that participates in several age-related diseases. Using stable isotope labeling with amino acids in cell culture (SILAC), we identify 343 SASP proteins that senescent human fibroblasts secrete at 2-fold or higher levels compared to quiescent cell counterparts. Bioinformatic analysis revealed that 44 of these SASP factors are involved in hemostasis, a process not previously linked with cellular senescence. We validate the expression of some of these SASP factors in cell culture and in vivo. Mice treated with the chemotherapeutic agent doxorubicin, which induces widespread cellular senescence in vivo, show increased blood clotting. Conversely, use of a transgene that permits the selective removal of senescent cells shows that senescent cell clearance attenuates the increased clotting shown by doxorubicin-treated mice. Together, our study characterizes a SASP profile using SILAC, unveiling a novel function for cellular senescence in hemostasis.