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Ikuroh Ohsawa

Publications and source records attributed to Ikuroh Ohsawa.

14 recordsLinked to original sources
PubMed2006

Dysfunction of mitochondria and oxidative stress in the pathogenesis of Alzheimer's disease: on defects in the cytochrome c oxidase complex and aldehyde detoxification.

The mitochondrion is an organelle that plays a central role in energy production. It, at the same time, generates reactive oxygen species as by-products. Large-scale epidemiological case-control studies suggest the involvements of dihydrolipoamide succinyltransferase (DLST) of the mitochondrial Krebs cycle and mitochondrial aldehyde dehydrogenase-2 (ALDH2) in Alzheimer's disease (AD). The DLST gene has two gene-products, one of which, a novel gene product MIRTD, mediates the molecular assembly of the cytochrome c oxidase complex whose defect has been a candidate of the causes of AD. Since levels of MIRTD mRNA in the brains of AD patients were significantly low, a decrease in MIRTD could affect energy production. ALDH2, a matrix enzyme, was found to act as a protector against oxidative stress through oxidizing toxic aldehydes, such as 4-hydroxy-2-nonenal, that are spontaneously produced from lipid peroxides. Hence, a decrease in ALDH2 activity is proposed to contribute to AD. Indeed, transgenic mice with low activity of ALDH2 exhibited an age-dependent neurodegeneration accompanying memory loss. Since amyloid beta peptide has been recently shown to be present in neuronal mitochondria to decline energy production and enhance ROS production, it has become possible to link AD more closely with roles of mitochondria in the pathogenesis.

Alcohol Dehydrogenase↗
PubMed2005

Association of alcohol dehydrogenase 2*1 allele with liver damage and insulin concentration in the Japanese.

The Japanese have a polymorphism in the alcohol dehydrogenase 2 gene (ADH2). The alleles of ADH2 (ADH2*1 and ADH2*2) encode more active and less active forms for ethanol metabolism, respectively. We examined whether liver damage and the insulin-glucose axis vary according to ADH2 genotype in the Japanese. The 2,232 subjects (1,126 men and 1,106 women) were recruited from a population-based prospective cohort study. Clinical evaluations including alcohol consumption, percentage of alcohol drinkers, plasma glucose, HbA1c, insulin, AST, ALT, gamma-GTP, and prevalence of diabetes were compared among the ADH2 genotypes. The percentage of drinkers, alcohol consumption, AST, ALT, and gamma-GTP were higher in group ADH2*1/1 than in group ADH2*1/2 or ADH2*2/2 (all P < 0.05). Hence, ADH2*1/1 is associated with excess alcohol intake and liver disorders. However, the prevalence of diabetes did not differ among the three groups. For the glucose-insulin axis, we examined subjects who did not receive insulin therapy or oral anti-diabetes medication. While amounts of alcohol consumed and glucose levels were nearly the same between ADH*1/2 and ADH2*2/2, insulin concentrations were lower in ADH2*2/1 than in ADH2*2/2 (P < 0.05 in men). This finding suggests that the ADH2*1 allele is associated with a lower insulin concentration when alcohol intake is light or moderate. It also suggests that the genetic effect of ADH2*1 plays an important role in alcohol drinking behavior and in the occurrence of liver injury, but the effect is so mild that it does not influence the glucose-insulin axis or prevalence of diabetes.

Alcohol Dehydrogenase↗
PubMed2005

The anti-cell death FNK protein protects cells from death induced by freezing and thawing.

The FNK protein, constructed from anti-apoptotic Bcl-xL with enhanced activity, was fused with the protein transduction domain (PTD) of the HIV/Tat protein to mediate the delivery of FNK into cells. The fusion protein PTD-FNK was introduced into chondrocytes in isolated articular cartilage-bone sections, cultured neurons, and isolated bone marrow mononuclear cells to evaluate its ability to prevent cell death induced by freezing and thawing. PTD-FNK protected the cells from freeze-thaw damage in a concentration-dependent manner. Addition of PTD-FNK with conventional cryoprotectants (dimethyl sulfoxide and hydroxyethyl starch) increased surviving cell numbers around 2-fold compared with controls treated only with the cryoprotectants. Notably, PTD-FNK allowed CD34+ cells among bone marrow mononuclear cells to survive more efficiently (12-fold more than the control cells) from two successive freeze-thaw cycles. Thus, PTD-FNK prevented cell death induced by freezing and thawing, suggesting that it provides for the successful cryopreservation of biological materials.

Animals↗
PubMed2005

Prognostic significance of the immunohistochemical index of survivin in glioma: a comparative study with the MIB-1 index.

OBJECTIVE: Survivin has been identified as a protein expressed in cancer cells and a member of the inhibitor-of-apoptosis protein family. Recent studies suggest that the expression of survivin increases during the G2/M phase of the cell cycle, and may be used in clinical prognosis. We examined whether survivin expression in human gliomas would be a correlative of prognosis. METHODS: We prepared polyclonal anti-survivin serum to establish a survivin index for stained sections, using an immunohistochemical procedure, according to the method used for scoring MIB-1 index, and then stained 29 paraffin-embedded sections from surgical specimens of 29 patients who were classified into three grades of World Health Organization with the mean age of low grade astocytoma (grade II) being 34.7; anaplastic astrocytoma (grade III), 48.8; and glioblastoma multiform (grade IV), 58.4. RESULTS: On staining with the anti-survivin antiserum, all specimens contained positive cells, but the survivin index was heterogeneous among grades. The mean percentage of immunoreactive cells in each specimen was 70.0 (SD 18.2) in grade II, 81.3 (16.5) in grade III, and 85.0 (13.6) in grade IV. Then we compared the survivin index to the MIB-1 index and found that in low-grade gliomas (grade II and III), the difference in survival times between the high and low survivin indexes was significant (P=0.007), whereas that between the high and low MIB-1 indexes was not significant (P=0.092). ONCLUSION: Survivin is more sensitive marker than MIB-1 for the evaluation of low-grade gliomas in that it helps to predict patient survival. Much larger glioma patient series are needed to validate the findings of our limited study.

Adult↗
PubMed2004

Green fluorescent protein causes mitochondria to aggregate in the presence of the Bcl-2 family proteins.

Green fluorescent protein (GFP) has been widely used in a variety of experiments in cell biology. When cells were co-transfected with the GFP gene and the bcl-2 family genes bcl-2, bcl-x(L), and bax, mitochondria appeared to aggregate at the periphery of the nucleus specifically where GFP was expressed. Little aggregation was seen in the presence of other members of the GFP family, EGFP (enhanced GFP), ECFP (enhanced cyan variant), and EYFP (enhanced yellow-green variant). GFP but not EGFP seemed to promote cell death induced by pro-apoptotic Bax. Thus, GFP specifically promotes the aggregation of mitochondria when co-expressed with a member of the Bcl-2 family in association with apoptosis.

Animals↗
PubMed2004

Mitochondrial ALDH2 deficiency as an oxidative stress.

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) plays a major role in ethanol metabolism. It is involved in acetaldehyde detoxification. A polymorphism of the ALDH2 gene is specific to North-East Asians. Sensitivity to ethanol is highly associated with this polymorphism (ALDH2(*)2 allele), which is responsible for a deficiency of ALDH2 activity. We first show that this deficiency influences the risk for late-onset Alzheimer's disease (LOAD) by a case-control study in a Japanese population. In a comparison of 447 patients with sex, age, and region-matched non-demented controls, the genotype frequency for the ALDH2(*)2 allele was significantly higher in the patients than in the controls (P=0.001). Next, we examined the combined effect of the ALDH2(*)2 and the apolipoprotein E4 allele (APOE-epsilon4), which has been confirmed to be a risk factor for LOAD. The ALDH2(*)2 allele more significantly affected frequency and age at onset in patients with APOE-epsilon4 than in those without it. These results indicate that the ALDH2 deficiency is a risk factor for LOAD, acting synergistically with the APOE-epsilon allele. Next, to elucidate the molecular mechanism involved, we obtained ALDH2-deficient cell lines by introducing mouse mutant ALDH2 cDNA into PC12 cells. We speculate that ALDH2 may act to oxidize toxic aldehyde derivatives. Then, we found that the ALDH2-deficient transfectants were highly vulnerable to exogenous 4-hydroxy-2-nonenal, an aldehyde derivative generated from peroxidized fatty acids. In addition, the ALDH2-deficient transfectants were sensitive to oxidative insult induced by antimycin A, accompanied by an accumulation of proteins modified with 4-hydroxy-2-nonenal. Mitochondrial ALDH2 functions as a protector against oxidative stress.

Aldehyde Dehydrogenase↗
PubMed2004

Detection of urine survivin in 40 patients with bladder cancer.

PURPOSE: We investigated whether urine survivin, an inhibitor of the apoptosis protein, is useful for diagnosing bladder tumor. METHOD: We measured urine survivin levels in 40 patients with bladder tumors and 9 healthy volunteers. RESULTS: The average urine survivin levels in the 40 patients and 9 healthy controls were not significantly different (3.802+/-8.669 and 1.127+/-1.529, respectively (p=0.3646) ). However, significantly high urine survivin levels were observed in 3 of the 40 patients, but not in healthy volunteers. Urine Cyfra 21-1 was not elevated (1.3 ng/ml) in one patient with a significantly elevated urine survivin level (33.54 ng/ml), while in two patients with elevated Cyfra (320 ng/ml and 240 ng/ml), the urine survivin level was not detectable. CONCLUSION: With improvements in the sensitivity of our Elisa system for urine survivin and combined use of urine Cyfra 21-1, it is possible that urine survivin will be a useful tumor marker in detecting both new-onset and recurrent bladder tumors.

Adult↗
PubMed2003

Genetic deficiency of a mitochondrial aldehyde dehydrogenase increases serum lipid peroxides in community-dwelling females.

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) plays a major role in acetaldehyde detoxification. The alcohol sensitivity is associated with a genetic deficiency of ALDH2. We and others have previously reported that such a deficiency influences the risk for late-onset Alzheimer's disease (LOAD), hypertension, and myocardial infarction. Then we tried to find phenotypes to which the ALDH2 polymorphism contributes by conducting several evaluations including biochemical and functional analyses of various tissues in a community-dwelling population. Several serum proteins, lipids, and lipid peroxides (LPO) levels showed differences between the nondefective (ALDH2*1/1) and defective (ALDH2*1/2 and ALDH2*2/2) ALDH2 individuals. However, alcohol-drinking behavior is known to affect these evaluations. Thus, we excluded the effects of alcohol-drinking behavior from the association with the ALDH2-deficient genotype through correction and found that the concentration of LPO was significantly lower in the nondefective ALDH2 females than the defective females. The effect of frequent alcohol-drinking behavior in males seems to override the phenotype of the high serum LPO level. These results indicate that the ALDH2 deficiency may enhance oxidative stress in vivo. Thus, these findings suggest that ALDH2 functions as a protector against oxidative stress and the decrease in protection may influence the onset of AD, hypertension, and myocardial infarction.

Adult↗
PubMed2003

Continuous culture of novel mitochondrial cells lacking nuclei.

We isolated stable cell lines, designated as mitochondrial cells, from cybrids obtained by fusing mitochondria-less HeLa cells with platelets from patients with Leigh syndrome, a subtype of mitochondrial encephalomyopathy. The cells contain a pathogenic point mutation, T9176C, in the mitochondrial DNA. Hematoxylin-eosin staining, confocal fluorescent microscopy and flow cytometry in fixed or living cells showed that the majority of these mitochondrial cells lack nuclear DNA and nuclei, but contain active mitochondria. Despite the absence of nuclear DNA, these cells can be continuously generated in culture. Therefore, it is likely that they arise from the minority of cells which possess a nucleus.

Journal Article↗
PubMed2003

Deficiency in a mitochondrial aldehyde dehydrogenase increases vulnerability to oxidative stress in PC12 cells.

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) plays a major role in acetaldehyde detoxification. The alcohol sensitivity is associated with a genetic deficiency of ALDH2. We have previously reported that this deficiency influences the risk for late-onset Alzheimer's disease. However, the biological effects of the deficiency on neuronal cells are poorly understood. Thus, we obtained ALDH2-deficient cell lines by introducing mouse mutant Aldh2 cDNA into PC12 cells. The mutant ALDH2 repressed mitochondrial ALDH activity in a dominant negative fashion, but not cytosolic activity. The resultant ALDH2-deficient transfectants were highly vulnerable to exogenous 4-hydroxy-2-nonenal, an aldehyde derivative generated by the reaction of superoxide with unsaturated fatty acid. In addition, the ALDH2-deficient transfectants were sensitive to oxidative insult induced by antimycin A, accompanied by an accumulation of proteins modified with 4-hydroxy-2-nonenal. Thus, these findings suggest that mitochondrial ALDH2 functions as a protector against oxidative stress.

Aldehyde Dehydrogenase↗
PubMed2002

Protection against ischemic brain injury by protein therapeutics.

Preventing massive cell death is an important therapeutic strategy for various injuries and disorders. Protein therapeutics have the advantage of delivering proteins in a short period. We have engineered the antiapoptotic bcl-x gene to generate the super antiapoptotic factor, FNK, with a more powerful cytoprotective activity. In this study, we fused the protein transduction domain (PTD) of the HIVTat protein to FNK and used the construct in an animal model of ischemic brain injury. When added into culture media of human neuroblastoma cells and rat neocortical neurons, PTD-FNK rapidly transduced into cells and localized to mitochondria within 1 h. It protected the neuroblastomas and neurons against staurosporine-induced apoptosis and glutamate-induced excitotoxicity, respectively. The cytoprotective activity of PTD-FNK was found at concentrations as low as 0.3 pM. Additionally, PTD-FNK affected the cytosolic movement of calcium ions, which may relate to its neuroprotective action. Immunohistochemical analysis revealed that myc-tagged PTD-FNK (PTD-myc-FNK) injected i.p. into mice can have access into brain neurons. When injected i.p. into gerbils, PTD-FNK prevented delayed neuronal death in the hippocampus caused by transient global ischemia. These results suggest that PTD-FNK has a potential for clinical utility as a protein therapeutic strategy to prevent cell death in the brain.

Animals↗
PubMed2002

Down-regulation of a novel gene, DRLM, in human liver malignancy from 4q22 that encodes a NAP-like protein.

Frequent observations of allelic loss in chromosomal band 4q21-22 in hepatocellular carcinoma (HCC) have suggested the presence of one or more tumor suppressor genes in this region. We screened HCC cell lines by reverse transcription-polymerase chain reaction (RT-PCR) to detect alterations in expression of genes within the region in question by examining expressed sequence tags located there. These experiments identified a full-length cDNA of 2311 bp in length encoding a novel, 182-amino-acid peptide belonging to the class of nucleosome assemble protein lacking nuclear localization signal sequence. Polyclonal antibody was raised by expression of a constructed recombinant glutathione S-transferase fusion protein. in vitro expression and Western blotting revealed that the novel protein distributed in cytoplasm. This gene showed loss or extreme decrease of expression in five of 13 HCC cell lines. We named it DRLM ('down-regulated in liver malignancy'). Our results suggest that loss of expression of DRLM at 4q21-22 may play an important role in human hepatocarcinogenesis.

3T3 Cells↗