SIRTUIN MODULATORS: LIMITING THE SENESCENCE ASSOCIATED SECRETORY PHENOTYPE IN RETINAL PIGMENT EPITHELIUM (RPE) CELLS

MARQUIONI-RAMELLA MD; TATE P; MARAZITA M; SUBURO AM

Congreso; LX REUNIÓN CIENTÍFICA ANUAL Sociedad Argentina de Investigación Clínica.; 2016

Cellular senescence triggers the expression of a wide variety of inflammatory factors named the senescence associated secretory phenotype (SASP). The SASP may contribute 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 oxidative-stress induced senescence in RPE cells dysregulates the expression of factors linked to AMD progression, like IL-8, VEGF and CFH. We now hypothesized that sirtuins, NAD-dependent deacetylases and key regulators of cellular stress response and aging, may modulate the SASP in RPE. Aims: To evaluate the effect of nicotinic acid (NA), a NAD+ precursor, and caffeic acid (CAF) a polyphenol with anti-inflammatory properties, on Sirtuins and SASP. Methods: Human derived RPE cells (ARPE-19 line) were incubated with 200 μM H2O2 for 90 minutes during 3 consecutive days and then maintained in fresh culture medium for seven days to establish senescent cultures. These cultures were exposed to 1 mM NA, or 6 μg/ml CAF for 8 days. Cells were collected and RNAm levels for IL-8, Sirtuin 1 (SIRT1) and Sirtuin 3 (SIRT3) analyzed by quantitative real time PCR. Senescence was determined by positive staining for Senescence Associated β-gal activity and increased expression of p21 and p16 by western blot. Results: NA and CAF upregulated SIRT3 and SIRT1 respectively, compared to senescent cultures without treatment (p < 0,05). Both, NA and CAF, significantly decreased IL-8 mRNA levels, a hallmark of the SASP (p < 0,05). Neither of them reverted other senescent markers (SA-β-gal+, p21, p16). Conclusions: NA and CAF negatively regulate a key component of the SASP without altering the tumor suppresive activity of senescence. Targeting SIRT1/3 might be a novel approach to control the SASP in RPE cells.