Jian-Fang Ma

Immunohistochemical evidence for macroautophagy in neurones and endothelial cells in Alzheimer's disease

J.‐F. Ma, Y. Huang, S.‐D. Chen and G. Halliday (2010) Neuropathology and Applied Neurobiology36, 312–319
Immunohistochemical evidence for macroautophagy in neurones and endothelial cells in Alzheimers disease

Methylation of α-synuclein and leucine-rich repeat kinase 2 in leukocyte DNA of Parkinson's disease patients.

BACKGROUND Recent studies highlight the role of DNA methylation in the pathogenesis of Parkinsons disease (PD). However, there is a paucity of studies exploring the role of blood-based DNA methylation in PD. We aimed to explore identifiable epigenetic biomarkers for PD by analyzing the methylation status of α-synuclein (SNCA) and leucine-rich repeat kinase 2 (LRRK2) in leukocytes. METHODS Bisulfite Specific PCR-based Sequencing method was used for semi-quantitative detection of methylation status of CpG islands in SNCA and LRRK2 promoter regions. Bisulfite Specific Cloning-based Sequencing method was used for further quantitative examination of CpG-2 methylation of SNCA. mRNA level was also detected in leukocytes. RESULTS Semi-quantitative detection showed that the methylation status of SNCA CpG-2 differed between PD patients and normal controls, while there was no difference in CpG-1 of SNCA or in LRRK2 promoter. Further quantitative analysis by clonal assay showed that the CpG-2 of SNCA was hypomethylated in PD patients compared with the normal control (5.90% versus 7.69%, P=0.034). Moreover, among the 14 CpG sites of CpG-2, the 2nd, 4th and 9th CpG sites were significantly hypomethylated in PD patients. In subgroups of PD, the methylation level decreased in the early-onset PD patients (P=0.001). RT-PCR examination showed that SNCA mRNA was increased in PD patients compared with normal control (P=0.003). CONCLUSIONS Our results indicated that the methylation level of SNCA CpG-2, especially that of the 2nd, 4th and 9th CpG sites in leukocytes might have great potential to be a useful and informative biomarker in PD diagnosis and treatment.

Plasma metabolite profiles of Alzheimer's disease and mild cognitive impairment.

Previous studies have demonstrated altered metabolites in samples of Alzheimers disease (AD) patients. However, the sample size from many of them is relatively small and the metabolites are relatively limited. Here we applied a comprehensive platform using ultraperformance liquid chromatography-time-of-flight mass spectrometry and gas chromatography-time-of-flight mass spectrometry to analyze plasma samples from AD patients, amnestic mild cognitive impairment (aMCI) patients, and normal controls. A biomarker panel consisting of six plasma metabolites (arachidonic acid, N,N-dimethylglycine, thymine, glutamine, glutamic acid, and cytidine) was identified to discriminate AD patients from normal control. Another panel of five plasma metabolites (thymine, arachidonic acid, 2-aminoadipic acid, N,N-dimethylglycine, and 5,8-tetradecadienoic acid) was able to differentiate aMCI patients from control subjects. Both biomarker panels had good agreements with clinical diagnosis. The 2 panels of metabolite markers were all involved in fatty acid metabolism, one-carbon metabolism, amino acid metabolism, and nucleic acid metabolism. Additionally, no altered metabolites were found among the patients at different stages, as well as among those on anticholinesterase medication and those without anticholinesterase medication. These findings provide a comprehensive global plasma metabolite profiling and may contribute to making early diagnosis as well as understanding the pathogenic mechanism of AD and aMCI.

Validation of the Chinese non-motor symptoms scale for Parkinson's disease: results from a Chinese pilot study.

OBJECTIVES To evaluate a Chinese version of the Non-Motor Symptoms Scale (NMSS) in Parkinsons disease (PD) as an instrument for measuring non-motor symptoms (NMSs) in Chinese patients with Parkinsons disease. METHODS We conducted a psychometric analysis of the Chinese version of NMSS using a cross-sectional study of 126 patients with PD. The battery also included the Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale (ESS), the Mini-Mental State Examination (MMSE), the Geriatric Depression Scale (GDS), and the Hamilton Anxiety Scale (HAMA), and was conducted by neurologists. RESULTS There were significant correlations between the NMSS and PSQI scores (rS=0.63, P<0.001), as well as the NMSS and ESS scores (rS=0.38, P<0.001). Furthermore, significant positive correlations between NMSS and GDS, NMSS and HAMA, and NMSS and disease duration were also observed. Importantly, the sleep/fatigue index of the NMSS significantly correlated with the PSQI and ESS findings, the mood/cognition index of the NMSS significantly correlated with the GDS and HAMA findings, and the attention/memory index of the NMSS significantly correlated with the MMSE findings. CONCLUSION The Chinese version of the NMSS can be considered a comprehensive, useful measure for NMS evaluation in Chinese PD patients.

Amyloid-beta1-42 induces reactive oxygen species-mediated autophagic cell death in U87 and SH-SY5Y cells.

Alzheimers disease (AD) is a neurodegenerative disorder initiated by the aggregation of amyloid-beta peptide (Abeta). Macroautophagy, which is essential for cell survival as well as the promotion of cell death, has been observed extensively in AD brains or transgenic mice overexpressing Abeta protein precursor. However, the role of macroautophagy in the pathogenesis of AD is unclear. In this study, we showed that Abeta1-42 triggered autophagic cell death in both human glioma cell line (U87 cell) and human neuroblastoma cell line (SH-SY5Y cell). Abeta1-42-induced cytotoxicity and autophagic cell death were blocked by the autophagy inhibitor 3-methyladenine (3-MA) or by small interfering RNA against the autophagy gene Beclin-1. Reactive oxygen species (ROS) accumulation was also detected in both Abeta1-42 treated cell lines and this accumulation was not affected by 3-MA. Moreover, pretreatment with the ROS scavenger N-acetylcysteine inhibited ROS accumulation and autophagic cell death induced by Abeta1-42, suggesting that Abeta1-42-induced ROS accumulation might trigger the onset of autophagy and subsequent autophagic cell death. These findings provide further insights into the mechanisms underlying Abeta-induced cytotoxicity.

Gene polymorphisms and risk of adult early-onset ischemic stroke: A meta-analysis

INTRODUCTION Genetic studies restricted to young adult ischemic stroke patients may help in excluding the potentially confounding variables encountered with advanced age; thus, allowing a more precise risk evaluation derived from the inherited mutations alone. Through meta-analysis, this study was conducted to determine the genetic risk contributed by each susceptibility gene polymorphism, particularly in adult early-onset ischemic stroke patients. MATERIALS AND METHODS Electronic databases were searched for all the case-control studies relating to any candidate genes for ischemic stroke. The range of age was 18-50 years for cases. Fixed or random effects model was used depending on the heterogeneity between studies. RESULTS Twenty-six studies were finally included in this meta-analysis; these studies focused on 7 candidate genes. A significant but modest association was identified for 2 polymorphisms, namely, methylenetetrahydrofolate reductase (MTHFR) C677T (OR = 1.44, 95% CI = 1.14-1.80) and apolipoprotein E (ApoE) epsilon2-4 (OR = 2.53, 95% CI = 1.71-3.73). Although the pooled analysis for platelet glycoprotein Ia (GPIa) C807T showed a positive association (OR = 1.50, 95% CI=1.10-2.05), the Eggers test indicated the existence of publication bias (t=5.27, P>|t|=0.034). CONCLUSIONS Genetic abnormalities specific to homocysteine and lipid metabolism increase the risk for ischemic stroke at an early age. These data may offer important implications for future genetic association studies for stroke.

Association Study of Clusterin Polymorphism rs11136000 With Late Onset Alzheimer’s Disease in Chinese Han Population

Objective: We conducted a case–control study to investigate whether clusterin polymorphism (rs11136000) was associated with late-onset Alzheimer’s disease in Chinese Han population. Methods: Polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) assay was performed on genotype rs11136000 and APOEε4 in 127 patients with late-onset Alzheimer’s disease and 143 control individuals. Previous published data from other Chinese samples was also included for further meta-analysis. Results: APOEε4 was demonstrated to increase the risk of Alzheimer’s disease in Chinese population (odds ratio = 2.35, 95% confidence interval: 1.40-3.96). There is no significant association between clusterin rs11136000 with late-onset sporadic AD in our small cohort. However, meta-analysis revealed significant allele and genotype differences between Alzheimer’s disease and controls following a recessive model. Conclusion: Clusterin (rs11136000) was associated with Alzheimer’s disease in Chinese Han population.

2-methoxyestradiol attenuates autophagy activation after global ischemia.

BACKGROUND Hypoxia inducible factor 1 (HIF-1) is a key transcriptional factor activated during cerebral ischemia, which regulates a great number of downstream genes, including those associated with cell death. In the present study, we aimed to test the hypothesis that post-ischemic HIF-1α up-regulation might promote autophagy activation; thereby, HIF-1α inhibitor 2ME2 might prevent neurons from ischemic injury through inhibiting autophagy. METHODS Global ischemia was induced using the four-vessel occlusion model (4-VO) in Sprague-Dawley rats (male, 250-280g). 2-Methoxyestradiol (2ME2, 5mg/kg, i.p.) was administrated to down-regulate HIF-1α expression. Post-ischemic beclin-1 and LC3 protein expression was determined at different time points through Western blot assay. Neuronal injury was determined by cresyl violet staining and TUNEL staining in coronal histological sections. RESULTS The expression of beclin-1 and the ratio of LC3-II/LC3-I increased significantly at 12 and 24 h after ischemia. 2ME2 could remarkably inhibit the up-regulation of beclin-1 and the increase of LC3-II/LC3-I ratio during reperfusion. Moreover, 2ME2 and 3-MA exhibited powerful protective effects against ischemic/reperfusion induced neuronal injury. CONCLUSIONS This study confirmed that autophagy participated in post-ischemic neuronal injury. 2ME2, a HIF-1α inhibitor, might significantly decrease autophagy activation after cerebral ischemia and relieve post-ischemic neuronal injury. Our findings demonstrate that autophagy could be a potential target for neuronal protection after cerebral ischemia.

Curcumin inhibition of JNKs prevents dopaminergic neuronal loss in a mouse model of Parkinson's disease through suppressing mitochondria dysfunction

Curcumin,a natural polyphenol obtained from turmeric,has been implicated to be neuroprotective in a variety of neurodegenerative disorders although the mechanism remains poorly understood. The results of our recent experiments indicated that curcumin could protect dopaminergic neurons from apoptosis in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson’s disease (PD). The death of dopaminergic neurons and the loss of dopaminergic axon in the striatum were significantly suppressed by curcumin in MPTP mouse model. Further studies showed that curcumin inhibited JNKs hyperphosphorylation induced by MPTP treatment. JNKs phosphorylation can cause translocation of Bax to mitochondria and the release of cytochrome c which both ultimately contribute to mitochondria-mediated apoptosis. These pro-apoptosis effect can be diminished by curcumin. Our experiments demonstrated that curcumin can prevent nigrostriatal degeneration by inhibiting the dysfunction of mitochondrial through suppressing hyperphosphorylation of JNKs induced by MPTP. Our results suggested that JNKs/mitochondria pathway may be a novel target in the treatment of PD patients.

Analysis of genome ‐ wide association study ‐ linked loci in Parkinson's disease of Mainland China

Genome‐wide association studies (GWAS) have identified numerous single‐nucleotide polymorphisms (SNPs) that can modulate the risk of developing Parkinsons disease (PD).