Neuroprotective effects of extra virgin oils: a proteomic approach

Neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease are the largest growing area of neurological research still in search of an effective therapy. Extra virgin olive oil is a rich source of phenolic compounds, which have been demonstrated to interfere with different mechanisms involved in neurodegenerative disorders. Nonetheless the chemical composition of the oils could be influenced by the cultivar, the growing area, the ripening of the fruit, the processing and preservation of the oil. The aim of this research was to evaluate the effect of four different extra virgin olive oil extracts (named “collina”, “pianura”, “corniolo”, “spes”) on the proteome of the human neuroblastoma cell line (SH-SY5Y) differentiated with retinoic acid. The different olive oil extracts were characterized for their content in phenols and polyphenols by HPLC. To study the effect of oil components on SH-SY5Y proteome, cellular protein expression was analyzed by 2-DE before and after treatment with extra virgin oil extracts at a 10 μg/ml concentration. Same spots analysis suggested that all extracts induced changes of protein expression as compared to control. Fifty-nine exclusive spots were detected for “collina”, 11 for “pianura”, 87 for “corniolo” and 19 for “spes”. Spots of interest were cut, trypsin digested and resulting peptides were processed for MS/MS identification. Proteins identified suggest that extra-virgin olive oil extracts induced changes in protein expression involved in different pathways of the differentiated human neuroblastoma cell line. In particular all the extracts increased the expression of proteins involved in protein metabolism and syntesis such as Elongation factor 1-delta, Arginine-tRNA ligase, Proteasome subunit a type-2, Pyruvate kinase PKM, and ATP-dependent 6-phosphofructokinase. Overall our results might contribute to explain the extra-virgin olive oil nutraceutical effects at a molecular level.