S’ heels of senescent cells, Y. Zhu et al.(A) (B)(C)(D)(E)(F)(G)(H)(I)Fig. 3 Dasatinib and quercetin reduce senescent cell abundance in mice. (A) Effect of D (250 nM), Q (50 lM), or D+Q on levels of senescent Ercc1-deficient murine embryonic fibroblasts (MEFs). Cells were exposed to drugs for 48 h prior to analysis of SA-bGal+ cells using C12FDG. The data shown are means ?SEM of three replicates, ***P < 0.005; t-test. (B) Effect of D (500 nM), Q (100 lM), and D+Q on senescent bone marrow-derived mesenchymal stem cells (BM-MSCs) from progeroid Ercc1?D mice. The senescent MSCs were exposed to the drugs for 48 dar.12324 are implicated in protection of cancer and other cell types from apoptosis (Gartel Radhakrishnan, 2005; Kortlever et al., 2006; Schneider et 
al., 2008; Vousden Prives,2009). We found that p21 siRNA is senolytic (Fig. 1D+F), and PAI-1 siRNA and the PAI-1 inhibitor, tiplaxtinin, also may have some senolytic activity (Fig. S3). We found that siRNA against another serine protease?2015 The Authors. Aging Cell published by the Anatomical Society and John Wiley Sons Ltd.Senolytics: Achilles’ heels of senescent cells, Y. Zhu et al.(A)(B)(C)(D)(E)(F)Fig. 4 Effects of senolytic agents on cardiac (A ) and vasomotor (D ) function. D+Q significantly improved left ventricular ejection fraction of 24-month-old mice (A). Improved systolic function did not occur due to increases in cardiac preload (B), but was instead a result of a reduction in end-systolic dimensions (C; Table S3). D+Q resulted in modest improvement in endothelium-dependent relaxation elicited by acetylcholine (D), but profoundly improved vascular smooth muscle cell relaxation in response to nitroprusside (E). Contractile responses to U46619 (F) were not significantly altered by D+Q. In panels D , relaxation is expressed as the percentage of the preconstricted baseline value. Thus, for panels D , lower values indicate improved vasomotor function. N = 8 male mice per group. *P < 0.05; A : t-tests; D : ANOVA.inhibitor (serpine), PAI-2, is senolytic (Fig. 1D+.