A PROTEOMIC APPROACH TO STUDY THE NEUROPROTECTIVE EFFECT OF OLEOCANTHAL IN SH-SY5Y CELLS

Background: Olive leaves and virgin olive oil contain many phenolics effective against aging and several lifestyle-related diseases, including neurodegeneration, both in animal models and in humans. Oleocanthal is a secoiridoid, one of the most represented class of phenols in olive oil, and it is responsible of the stinging effect at pharynx level perceived after extra virgin olive oil ingestion. Recently, different studies demonstrated that oleocanthal possesses anti-aggregation activities on tau protein and Ibuprofen-like activity thanks to its ability to inhibits COX-1 and COX-2. The aim of this work is to investigate the neuroprotective effect of oleocanthal in neuron-like SH-SY5Y cells before and after oxidative stress induced by H2O2. Methods: Using 2DE coupled to mass spectrometry the protein maps for different conditions of treatment have been obtained and analyzed by Same spots (TotalLab). PCR analyses were performed to validate proteomic results. Results: Seventeen spots resulted significantly differentially expressed with respect to control after treatment with hydrogen peroxide, twenty-seven after treatment with oleocanthal (10 µM) followed by hydrogen peroxide, while two spots for direct effect of oleocanthal. Spots of interest were excised and identified by LC/MS/MS. Oleocanthal significantly reverted the down-regulation induced by hydrogen peroxide of 26S proteasome non-ATPase regulatory subunit 1, proteasome subunit beta type-4, Ubiquitin carboxyl-terminal hydrolase and Pyruvate kinase, moreover it increased the expression of Heat shock protein HSP 90-beta and Protein DJ1. Moreover, 10 µM oleocanthal was able to counteract oxidative stress induced by H2O2 in SH-SY5Y as measured by MTT viability assay and to increase reduced-GSH level both in the absence and in the presence of H2O2 as measured by monochlorobimane assay. Conclusions: Our findings suggest that oleocanthal may have beneficial health effect in counteracting neurodegeneration. Keywords: oleocanthal, SH-SY5Y cells, oxidative stres