RESUMO
As a result of accumulating methylglyoxal and advanced glycation end products in the brains of patients with Alzheimer's disease, it is considered a protein precipitation disease. The ubiquitin proteasome system is one of the most important mechanisms for cells to degrade proteins, and thus is very important for maintaining normal physiological function of the nervous system. This study recruited 48 individuals with Alzheimer's disease (20 males and 28 females aged 75 ± 6 years) and 50 healthy volunteers (21 males and 29 females aged 72 ± 7 years) from the Affiliated Hospital of Youjiang Medical University for Nationalities (Baise, China) between 2014 and 2017. Plasma levels of malondialdehyde and H2O2 were measured by colorimetry, while glyoxalase 1 activity was detected by spectrophotometry. In addition, 20S proteasome activity in erythrocytes was measured with a fluorescent substrate method. Ubiquitin and glyoxalase 1 protein expression in erythrocyte membranes was detected by western blot assay. The results demonstrated that compared with the control group, patients with Alzheimer's disease exhibited increased plasma malondialdehyde and H2O2 levels, and decreased glyoxalase 1 activity; however, expression level of glyoxalase 1 protein remained unchanged. Moreover, activity of the 20S proteasome was decreased and expression of ubiquitin protein was increased in erythrocytes. These findings indicate that proteasomal and glyoxalase activities may be involved in the occurrence of Alzheimer's disease, and erythrocytes may be a suitable tissue for Alzheimer's disease studies. This study was approved by the Ethics Committee of Youjiang Medical University for Nationalities (approval No. YJ12017013) on May 3, 2017.
RESUMO
OBJECTIVE: Protofibrils of alpha-synuclein mediate neuronal cell death and propagate Parkinson's disease (PD). In this study, we investigated the relationship between the rs3822086 C>T polymorphism located in the fourth intron of the alpha-synuclein (SNCA) gene and susceptibility to PD in a Chinese Han population. METHODS: 146 PD patients and 144 sex- and age-matched healthy individuals (control group) were selected for this study. The SNCA rs3822086 polymorphism was examined in all 300 study subjects by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. RESULTS: The genotype and allele frequencies of the SNCA rs3822086 polymorphism showed significant differences between the PD group and control group (TT: 25.3% vs. 18.8%, p=0.035; CT+TT: 77.4% vs. 66.0%, p=0.031; T allele: 51.4% vs. 42.4%, p=0.030; respectively). Stratified analyses based on gender indicated that male PD patients exhibited higher genotype and allele frequencies of the SNCA rs3822086 polymorphism compared to healthy male controls (TT: 26.7% vs. 13.2%, p=0.011; CC+CT: 73.3% vs. 86.8%, p=0.024; T allele: 51.2% vs. 37.9%, p=0.012; respectively). Age-stratified analyses indicated that the genotype and allele frequencies of the SNCA rs3822086 polymorphism were significantly higher in PD patients older than 60 years in comparison to healthy controls (TT: 32.2% vs. 20.5%, p=0.014; CT+TT: 77.0% vs. 60.2%, p=0.017; T allele: 54.6% vs. 40.3%, p=0.008; respectively). CONCLUSION: Our findings demonstrate that the SNCA rs3822086 C>T polymorphism correlates with increased susceptibility to PD among the Chinese Han population.
