SASP-LIKE PHENOTYPE IN ALZHEIMER CELLULAR MODELS: MODULATION BY NATURAL PHENOLIC COMPOUNDS

Our project aims to reduce, through the use of low concentrations of polyphenols, the secretion of inflammatory factors and to modulate the proteolytic/autophagic activity in Alzheimer’s Disease (AD) fibroblasts to target AD pathogenesis. Recent studies show an alteration in the autophagic process in early stages of AD and the possibility to modulate this mechanism by natural compounds. Resveratrol and oleuropein, two polyphenols of red grapes and olive oil respectively, are promising agents against neurodegenerative diseases since they reduce inflammation, which is directly involved in AD pathogenesis. We aim to modulate the pro-inflammatory phenotype in AD fibroblasts by targeting SASP (Senescence Associated Secretory Phenotype) factors, common to activated microglia secretion. Dermal fibroblasts from healthy donors (Control) or AD patients have been analyzed for autophagy modulation through LC3II/LC3I protein expression ratio. Control and AD cultures were treated for 7 days without or with 10 microM (R10) resveratrol or 50 microM oleuropein (OLE). Then autophagy was induced by 6h-starvation (RPMI without Glucose-FBS) and by addition of rapamycin 1 microM or TGFbeta 10 ng/mL. RT-PCR and zymography experiments were performed to analyze the expression and the production of SASP-related factors. As expected, basal LC3II/LC-3I ratio was reduced in AD compared to Control. Starvation seemed to be the most effective treatment to induce autophagy, and the pre-treatment with R10 increased LC3II/LC-3I ratio in AD cultures. OLE pre-treatment did not affect this parameter. Accordingly, a reduction in the genetic expression of uPA and MMP-9 (SASP factors) was observed in R10 AD compared to untreated AD fibroblasts. These data were confirmed by the zymogram analysis that showed a downregulation of MMP-9 activity in conditioned media from R10-treated AD cultures. Our results show that a nutraceutical approach targeting the SASP-like phenotype of AD fibroblasts could serve as model to counteract the pathogenetic process of the disease.