Identification of Serum Anti-GADD34 Antibody as a Common Marker ofDiabetes Mellitus and Parkinson Disease

Abstract

Background: Growth arrest and DNA-damage-inducible gene 34 (GADD34) has been identified as an antigen by serological identification of antigens by cDNA expression cloning (SEREX) using the sera of patients with atherosclerosis. It is possible that GADD34 is associated with atherosclerosis-related diseases such as diabetes mellitus (DM), acute-phase cerebral infarction (aCI), cardiovascular disease (CVD), and chronic kidney disease (CKD) as well as endoplasmic reticulum stress-related Parkinson disease (PD). Methods: GADD34 protein was bacterially expressed and purified. Amplified luminescent proximity homogeneous assay (AlphaLISA) was used to evaluate serum antibody levels against GADD34 protein in serum samples. Results: AlphaLISA revealed significantly higher serum antibody levels against GADD34 protein in patients with DM, aCI and CVD than those in healthy donors (HDs). The difference in levels between DM and HD was more prominent than that between aCI or CVD and HDs. The anti-GADD34 antibody levels were also elevated in the sera of diabetic CKD patients; thus, the anti-GADD34 antibodies appeared to be the most associated with DM, which is also a risk factor of PD. Anti-GADD34 antibody levels were also higher in patients with PD but not in those with amyotrophic lateral sclerosis as compared with those in HDs. Conclusion: Anti-GADD34 antibody may be a useful diagnostic tool for DM and PD. GADD34 may account for the pathophysiological relationship between DM and PD.