CONICET | Buscador de Institutos y Recursos Humanos

Cellular senescence triggers the expression of a wide variety of inflammatory factors named the senescence associated secretory phenotype (SASP). The SASP contributes to diseases of aging by disrupting tissue structure and function. Age-related macular degeneration (AMD) is a progressive disease which leads to irreversible loss of vision. Cell senescence of the retinal RPE is suggested to play a central role in the etiology of AMD. We have previously showed that Caffeic acid (CAF) and Chlorogenic acid (CLO) control the SASP of oxidative-stress induced senescent RPE cells. Now, we aim to determine the molecular mechanism underlying these beneficial effects. Methods: Human RPE cells (ARPE-19 line) were incubated with 150 μM H2O2 for 90 minutes during 3 days and then maintained for nine days to establish senescent cultures (SEN). These cultures were exposed to CAF 30 uM or CL 50 uM for the last 6 days in the presence or absence of SIRT1 inhibitor, Ex 527. RNAm and protein levels for IL1-, IL-6 were analyzed by western blot (WB). Senescence was determined by positive staining for Senescence Associated β-gal activity and increased expression of p21 and p16.gH2AX was tested by IFI. Results: Senescent cells showed activated phospho - p38 (Tyr 182) and phospho-NF-κB p65 (Ser536). Polyphenols inactivated these pathways. CAF and CL diminished p16 expression. In contrast, no changes were found on p21, gH2AX or SA-β-gal+ staining. SIRT1 inhibition prevented CAF and CLO effects on p38 and p65 phosphorylation as well as on IL-1b and IL-6 expression. Conditioned medium (CM) from SEN cultures promoted increased H2AX and SA-β-gal+ staining in control cells. The paracrine effects were prevented by CM from CAF and CL- treated cells. Conclusions: CAF and CL treatments control SASP expression in a SIRT1-dependent manner. Therapeutic interventions based on polyphenols might block senescence detrimetal effects in age-related pathologies