Association between DNA Methylation of the BDNF Promoter Region and Clinical Presentation in Alzheimer's Disease.

BACKGROUND/AIMS: In the present study, we examined whether DNA methylation of the brain-derived neurotrophic factor (BDNF) promoter is associated with the manifestation and clinical presentation of Alzheimer's disease (AD). METHODS: Of 20 patients with AD and 20 age-matched normal controls (NCs), the DNA methylation of the BDNF promoter (measured using peripheral blood samples) was completely analyzed in 12 patients with AD and 6 NCs. The resulting methylation levels were compared statistically. Next, we investigated the correlation between the DNA methylation levels and the clinical presentation of AD. RESULTS: The total methylation ratio (in %) of the 20 CpG sites was significantly higher in the AD patients (5.08 ± 5.52%) than in the NCs (2.09 ± 0.81%; p < 0.05). Of the 20 CpG sites, the methylation level at the CpG4 site was significantly higher in the AD subjects than in the NCs (p < 0.05). Moreover, the methylation level was significantly and negatively correlated with some neuropsychological test subscores (registration, recall, and prehension behavior scores; p < 0.05). CONCLUSION: These results suggest that the DNA methylation of the BDNF promoter may significantly influence the manifestation of AD and might be associated with its neurocognitive presentation.

Genetic Association between Neurotrophin-3 Polymorphisms and Alzheimer's Disease in Japanese Patients.

BACKGROUND: Some polymorphisms of the neurotrophin family have previously been investigated as candidate genes for Alzheimer's disease (AD). In the present study, we examined whether neurotrophin-3 (NTF-3) polymorphisms are genetic risk factors in patients with AD. METHODS: From a sample of 507 subjects, we recruited 248 age-matched subjects divided into 2 groups: AD patients (n = 143) and normal controls (NCs) (n = 105). We identified 3 representative NTF-3 single nucleotide polymorphisms (SNPs): rs6332, rs6489630, and rs4930767. Next, we statistically compared the allele frequencies of each SNP between the AD and NC groups in the early-onset (<65 years) cases under a more limited age-matched condition. RESULTS: We found a significant association between rs6332 and the total group of AD patients (p = 0.013) and significant associations between both rs6332 (p = 0.033) and rs6489630 (p = 0.035) and early-onset AD patients. CONCLUSION: These results suggest that NTF-3 SNPs may not only be associated with AD itself, but also with early-onset AD in Japanese patients, assuming that the NTF-3 gene may have age-related effects on neurodegenerative diseases.

Association between neurotrophin-3 polymorphisms and executive function in Japanese patients with amnestic mild cognitive impairment and mild Alzheimer disease.

BACKGROUND: We investigated whether neurotrophin (NT)-3 polymorphisms influenced the executive function of patients with 2 separate disease stages with similar dementia conditions: amnestic mild cognitive impairment (A-MCI) or mild Alzheimer disease (AD). METHODS: Among 215 outpatients with dementia and MCI, 155 with mild AD (n = 108) or A-MCI (n = 47) were recruited and divided into three genotypic groups based on the representative NT-3 functional polymorphisms rs6332 and rs6489630. Next, we compared the frontal assessment battery (FAB) total and subtest scores between the three genotypic groups. RESULTS: The total FAB score was not significantly associated with the rs6332 and rs6489630 genotypes; however, the conflicting instructions score among the 6 subtests was significantly associated with the rs6332 genotype (p < 0.05). Moreover, in patients with mild AD, the conflicting instructions score differed significantly among the three genotypic groups of rs6332 (p < 0.05) (G/G < A/A: p = 0.042 and G/A < A/A: p = 0.041). No significant differences in any other demographic variables were observed among the three genotypes of rs6332 and rs6489630. CONCLUSION: These results suggested that an NT-3 polymorphism, rs6332, may significantly influence executive function, reflecting interference performances among patients with mild-stage AD.

Association between nerve growth factor gene polymorphism and executive dysfunction in Japanese patients with early-stage Alzheimer's disease and amnestic mild cognitive impairment.

BACKGROUND/AIMS: To address the clinical neurocognitive roles of nerve growth factor (NGF) genetic polymorphism in early-stage Alzheimer's disease (AD) and amnestic mild cognitive impairment (A-MCI), we investigated the association between this single-nucleotide polymorphism (SNP) and executive dysfunction as a nonmemory cognitive impairment. METHODS: Among 200 outpatients with dementia and MCI whose NGF SNP rs6330 genotype was identified, those with A-MCI (n = 35) and early-stage AD (n = 67) were recruited and divided into three groups according to genotype (C/C: n = 58, C/T: n = 39, T/T: n = 5). Then, the Frontal Assessment Battery (FAB) scores were compared among the three (C/C, C/T, T/T) or two (C/C, T carrier) genotype groups. RESULTS: Among the subtests, a significant difference was only noted for the go/no-go scores (p < 0.01) between C/C and T carriers. However, no significant differences in the demographic variables and other neuropsychological subtest scores reflecting attentional and memory function were observed among the genotypes. CONCLUSION: Regarding the functional roles of neurotrophin polymorphisms as they relate to executive dysfunction, the NGF gene rs6330 might influence the inhibition task in Japanese patients with early-stage AD or A-MCI.

Frequent splicing aberration of the base excision repair gene hMYH in human gastric cancer.

BACKGROUND: Missense mutation of hMYH, which prevents transversion mutations induced by oxidative DNA damage, is reportedly associated with the development of gastric and colon cancer. We investigated whether deficiency or mutation of hMYH is associated with gastric carcinogenesis. PATIENTS AND METHODS: Thirty patients with gastric carcinoma, three gastric cancer cell lines and lymphocytes from three healthy volunteers were investigated. Reverse transcription-polymerase chain reaction (RT-PCR) was performed for hMYH, and the full-length sequence of hMYH mRNA was analysed. RESULTS: A silent mutation at codon 473 was seen in two tumours. Single nucleotide polymorphism at codon 345 was observed in 14 patients. These two base substitutions had no pathogenic effect. Seven splice variants were observed and two aberrant transcripts were detected more frequently in cancer specimens (67%) than in normal mucosa (10%). CONCLUSION: The high frequency of splicing aberration in cancer tissues suggests that aberrant transcripts may be involved in gastric carcinogenesis and cancer development.

A novel positive regulatory element for exfoliative toxin A gene expression in Staphylococcus aureus.

A 1.4 kb positive regulatory element (ETA(exp)) that controls staphylococcal exfoliative toxin A (sETA) transcription was cloned from Staphylococcus aureus. ETA(exp) is located upstream of the cloned 5.8 kb eta gene (etaJ1) obtained from the chomosomal DNA of S. aureus ZM, the standard ETA-producing strain. The cETA prepared from an Escherichia coli transformant into which the recombinant plasmid petaJ1 (5.8 kb eta/pUC9) had been introduced was expressed at high levels in the culture supernatant and the ammonium-sulfate-precipitated culture supernatant fraction as shown by immunoblotting and the single radial immunodiffusion test. However, cETA produced by the recombinant plasmid petaJ3 containing the 1.7 kb eta sequence (etaJ3) with a 1.45 kb ETA(exp)-deficient eta fragment (1.7 kb eta/pUC9) obtained from the 5.8 kb eta sequence by subcloning was not detected in either the culture supernatant or the ammonium-sulfate-precipitated culture supernatant fraction (167-fold concentrate of the culture supernatant) by immunoblotting or the single radial immunodiffusion test. A large amount of cETA was produced by the 1.7 kb eta sequence when it was linked to ETA(exp) amplified by PCR (1.7 kb eta-ETA(exp)/pUC9), regardless of the orientation of ETA(exp) insertion. Northern blot hybridization showed lower levels of the transcripts of the 1.7 kb eta sequence than of the 5.8 kb eta sequence. The rsETA prepared from an S. aureus transformant into which the recombinant plasmid 3.4 kb eta-ETA(exp)/pYT3 (pYT3-etaJ6) had been introduced was expressed at high levels in the culture supernatant fraction as shown by the latex agglutination test. However, the agglutination titre in the culture supernatant fraction of rsETA produced by the recombinant plasmid (1.7 kb eta/pYT3) containing the 1.7 kb eta sequence carrying the 1.4 kb ETA(exp)-deficient eta fragment (pYT3-etaJ3) was 2500-4000 times lower than that of pYT3-etaJ6.

Lack of BCL10 mRNA mutation in lymphold malignancies.

BACKGROUND: BCL10, a gene involved in the chromosomal translocation t(1;14)(p22;q32) found in mucosa-associated lymphoid tissue lymphoma (MALT lymphoma), has shown mutation in not only MALT lymphomas but also other lymphold tumors. However, the mutation rate remains controversial. One possible reason is variation in the source material (DNA or RNA), with most studies having been done using tumor DNA. Accordingly, we studied BCL10 mutations using tumor RNA. MATERIALS AND METHODS: Fifty lymphoid malignancies (26 malignant lymphomas, 10 chronic lymphocytic leukemias and 14 acute lymphoblastic leukemias) were examined. Total RNA was extracted from the tumor cells and first-strand cDNA was subjected to single-strand conformation polymorphism and fragment length analysis. Then the results were confirmed by direct sequencing. RESULTS: No mutations of the BCL10 gene were found in the 50 samples. There were four polymorphisms (3G to T, 24G to C, 485C to T and 638G to A). All samples showed at least one 24C allele. CONCLUSION: The BCL10 mutations studied are rare events at the RNA level and may not be associated with the mechanism of tumorigenesis in most lymphoid tumors.

DNA topoisomerase II inhibitor, etoposide, induces p21WAF1/CIP1 through down-regulation of c-Myc in K562 cells.

BACKGROUND: Anticancer agents modulate gene expression and these changes are essential for tumor cell killing. To investigate the mechanism by which etoposide acts as an anticancer agent, the relationship between p21WAF1/CIP1 (p21) and c-Myc was studied. MATERIALS AND METHODS: K562 cells with and without ectopic c-Myc expression were studied. Apoptosis was detected using propidium iodide and Hoechst 33342 double staining. The c-Myc and p21 levels were studied by RT-PCR and immunoblot. The p21 promoter (from -205 to +67) was investigated by the luciferase reporter gene assay. RESULTS: Ectopic c-Myc-expressing K562 (K562/c-Myc) cells showed more extensive apoptosis than K562 cells after continuous exposure to 200 microM etoposide for 24 hours. During this treatment, p21 expression was not observed in K562/c-Myc cells, and the expression of c-Myc and p21 was mutually exclusive. Etoposide activated the p21 promoter in a concentration-dependent manner, and etoposide-induced luciferase activity was suppressed by co-transfection of c-Myc. CONCLUSION: p21 promoter activity was repressed by c-Myc in proliferating K562 cells, and detoposide-induced down-regulation of c-Myc released this suppression, resulting in the induction of p21.