Antiaging Effects of Urolithin A on Replicative Senescent Human Skin Fibroblasts

Although the health benefits attributed to urolithin A, such as anticancer, anti-inflammatory, and antioxidant effects, are based on numerous, diverse studies carried out in vitro, the biological effects of urolith A are still not entirely understood. In this study, we explored the biological effects of urolithin A using senescent human skin fibroblasts (HSFs) to determine whether urolithin A has any antiaging potential. Our results showed that urolithin A significantly increased type I collagen expression and reduced matrix metalloproteinase 1 (MMP-1) expression. Urolithin A also reduced intracellular reactive oxygen species, which may be partially due to activation of the Nrf2-mediated antioxidative response. These results indicate that urolithin A is a promising antiaging agent. Meanwhile, we noticed that the 50 μM urolithin A could cause changes in cell morphology and inhibition in cell proliferation, which were due to cell cycle arrest in G2/M phase. However, SA-β-gal (senescence-associated β-galactosidase) staining and γH2AX immunofluorescence staining showed cellular senescence status of HSFs did not change. Results of DAPI (4'6-diamidino-2-phenylindole) staining (no significant change) increased BCL2 gene expression and mitochondrial membrane potential (no significant change) after urolithin A treatment showed that the cells did not undergo apoptosis. These results provided further insights into the molecular mechanism of urolithin A. In conclusion, urolithin A showed a strong potential of antiaging.