High fat diet induced isoform changes of the Parkinson’s disease protein DJ-1.

Genetic and environmental factors mediate via different physiological and molecular processes a shifted energy balance leading to overweight and obesity. To get insights in the underlying processes involved in energy intake and weight gain, we compared hypothalamic tissue of mice kept on a high-fat or control diet for 10 days by a proteomic approach. Using 2D difference gel electrophoresis in combination with LC-MS/MS, we observed significant abundance changes in 15 protein spots. One isoform of the protein DJ-1 was elevated in the high-fat diet group in the analyzed three different mouse strains SWR/J, C57BL/6N and AKR/J. Large scale validation of DJ-1 isoforms in individual samples and tissues confirmed a shift in the pattern of DJ-1 isoforms towards more acidic isoforms in several brain and peripheral tissues after feeding a high-fat diet for 10 days. The identification of an oxidation of cysteine 106 as well as a 2-succinyl modification of the same residue by mass spectrometry not only explains the isoelectric shift of DJ-1 but also links our results to similar shifts of DJ- 1 observed in neurodegenerative disease states under oxidative stress. We hypothesize that DJ-1 is a common physiological sensor involved in both nutrition-induced effects and neurodegenerative disease states