Altered acetylation of proteins in patients with rheumatoid arthritis revealed by acetyl-proteomics.

Post-translational modifications (PTMs) are often critical for the function of proteins as well as antigenicity of proteins. We here tried to elucidate alteration of PTMs in Rheumatoid arthritis (RA), focusing on acetylation. We applied acetyl-proteomics to peripheral blood mononuclear cells (PBMCs) to elucidate PTM difference between patients with RA and healthy donors.Proteins, extracted from peripheral blood mononuclear cells (PBMCs) of 7 RA patients and 7 healthy donors, were separated by 2-dimansional electrophoresis. Acetylation ratios of each protein spot were estimated by the combination of Sypro Ruby staining and anti-acetylated lysine antibodies. Proteins highly acetylated in the RA group were identified by mass spectrometry. Focusing on α-enolase (ENO1), one of the identified proteins, involvement of histone deacetylases (HDACs) in the high acetylation was investigated. Furthermore, the effects of acetylation on the activity of ENO1 were investigated.In PBMCs from the patients with RA, 29 acetylated protein spots were detected. One of highly acetylated proteins in the RA patients was identified as ENO1. The acetylation of ENO1 was found to be regulated in part by HDAC1. The enzymatic activity of ENO1 was up-regulated by acetylation.Highly acetylated ENO1 may play roles in the pathophysiology of RA through the maintenance of activated lymphocytes by increasing glycolysis-derived energy supply.