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Biomedical subjects

Yoko Nakano

Publications and source records attributed to Yoko Nakano.

At least 19 recordsLinked to original sources
PubMed2026

CASZ1 regulates the maturation of outer hair cells and is required for hearing in mice.

The transcription factor ATOH1 is a master regulator of mechanosensory hair-cell (HC) development in the ear. Here, we report that its target gene Casz1 regulates the maturation of outer HCs (OHCs). Genetic deletion of Casz1 during (but not after) cochlear development in the mouse caused: hearing loss; disorganization of mechanosensory stereocilia bundles in OHCs; reduced F-actin density in OHC cuticular plates; progressive OHC loss; and mild morphological alterations in inner HCs. This deletion also altered gene expression, delaying downregulation of genes expressed in immature OHCs, including the actin regulator-encoding gene Coro2a, and accelerating upregulation of genes expressed in mature OHCs. Deleting Coro2a in Casz1 mutant mice restored F-actin density in cuticular plates but increased stereocilia bundle disorganization and hearing thresholds, revealing that CORO2A provides an overall beneficial effect. Our data indicate that CASZ1 regulates transcriptional and morphological maturation of OHCs, and that CASZ1 in maturing HCs is necessary for hearing.

CASZ1↗
PubMed2007

Critical roles for p22phox in the structural maturation and subcellular targeting of Nox3.

Otoconia are small biominerals in the inner ear that are indispensable for the normal perception of gravity and motion. Normal otoconia biogenesis requires Nox3, a Nox (NADPH oxidase) highly expressed in the vestibular system. In HEK-293 cells (human embryonic kidney cells) transfected with the Nox regulatory subunits NoxO1 (Nox organizer 1) and NoxA1 (Nox activator 1), functional murine Nox3 was expressed in the plasma membrane and exhibited a haem spectrum identical with that of Nox2, the electron transferase of the phagocyte Nox. In vitro Nox3 cDNA expressed an approximately 50 kDa primary translation product that underwent N-linked glycosylation in the presence of canine microsomes. RNAi (RNA interference)-mediated reduction of endogenous p22phox, a subunit essential for stabilization of Nox2 in phagocytes, decreased Nox3 activity in reconstituted HEK-293 cells. p22phox co-precipitated not only with Nox3 and NoxO1 from transfectants expressing all three proteins, but also with NoxO1 in the absence of Nox3, indicating that p22phox physically associated with both Nox3 and with NoxO1. The plasma membrane localization of Nox3 but not of NoxO1 required p22phox. Moreover, the glycosylation and maturation of Nox3 required p22phox expression, suggesting that p22phox was required for the proper biosynthesis and function of Nox3. Taken together, these studies demonstrate critical roles for p22phox at several distinct points in the maturation and assembly of a functionally competent Nox3 in the plasma membrane.

Animals↗
PubMed2006

Symptoms underlying unawareness of memory impairment in patients with mild Alzheimer's disease.

Patients with Alzheimer's disease (AD) are often unaware of their cognitive impairment. This unawareness might have a multifactorial etiology, including impairment of cognitive domains and psychiatric symptoms. We conducted this study to determine the factors underlying unawareness of memory impairment (UMI) in patients with AD. In 103 patients with mild AD, the UMI was quantified as the difference between the patient's self-rating and the rating of the patient's caregiver on a standardized memory questionnaire system, the Everyday Memory Checklist. We then examined the relationships between UMI and memory, attention, language, visuospatial/constructive perception, frontal lobe function, and psychiatric symptoms. UMI was positively associated with memory impairment and delusions when effects of age, sex, and education were partialled out, suggesting that these symptoms are involved in the formation of UMI in the patients. Thus, existing treatments for memory impairment and delusions may be beneficial for increasing the awareness of mild AD patients of their cognitive impairment.

Affective Symptoms↗
PubMed2006

A mutation in RYK is a genetic factor for nonsyndromic cleft lip and palate.

OBJECTIVE: The RYK, EPHB2, and EPHB3 genes are attractive candidates for cleft lip and/or palate and cleft palate only pathogenesis. Both the Ryk-deficient mouse and Ephb2/Ephb3 (genes for interaction molecules with RYK) double-mutant mouse show cleft palate. SETTING: Mutation searches for RYK, EPHB2, and EPHB3 were carried out in a large number of Japanese and Vietnamese patients with cleft lip and/or palate and cleft palate only. Case-control study and transmission disequilibrium tests were performed also, using three single nucleotide polymorphisms within a linkage disequilibrium block in RYK. Seven haplotypes were constructed from the single nucleotide polymorphisms. RESULTS: A missense mutation, 1355G>A (Y452C), in RYK was identified in one Vietnamese patient with cleft lip and/or palate. This mutation was not found among 1646 Vietnamese, Japanese, and Caucasians, including 354 cleft lip and/ or palate and cleft palate only patients. Colony formation assay using NIH3T3 cells transfected with mutant cDNA revealed that mutant RYK had significantly reduced protein activity, compared with those with wild-type RYK, implying that the transformation ability of RYK is depleted by this mutation. Although a case-control study and transmission disequilibrium tests on three individual single nucleotide polymorphisms provided no evidence for association with oral clefts, a case-control study on one rare haplotype suggested a positive association in Japanese patients with cleft lip and/or palate and cleft palate only. No mutations in EPHB2 and EPHB3 were found in any patients examined. CONCLUSION: The findings suggested that a missense mutation, 1355G>A, and one rare single nucleotide polymorphisms haplotype may play a role in the development of cleft lip and/or palate in the Vietnamese, and cleft lip and/ or palate and cleft palate only in the Japanese.

3T3 Cells↗
PubMed2005

Induction and monitoring of definitive and visceral endoderm differentiation of mouse ES cells.

Preparation of specific lineages at high purities from embryonic stem (ES) cells requires both selective culture conditions and markers to guide and monitor the differentiation. In this study, we distinguished definitive and visceral endoderm by using a mouse ES cell line that bears the gfp and human IL2R alpha (also known as CD25) marker genes in the goosecoid (Gsc) and Sox17 loci, respectively. This cell line allowed us to monitor the generation of Gsc+ Sox17+ definitive endoderm and Gsc- Sox17+ visceral endoderm and to define culture conditions that differentially induce definitive and visceral endoderm. By comparing the gene expression profiles of definitive and visceral endoderm, we identified seven surface molecules that are expressed differentially in the two populations. One of the seven markers, Cxcr4, to which a monoclonal antibody is available allowed us to monitor and purify the Gsc+ population from genetically unmanipulated ES cells under the condition that selects definitive endoderm.

Animals↗
PubMed2005

PAX9 and TGFB3 are linked to susceptibility to nonsyndromic cleft lip with or without cleft palate in the Japanese: population-based and family-based candidate gene analyses.

The prevalence of nonsyndromic cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO) are believed to be higher in the Japanese than in Americans, Europeans or Africans. The purpose of this study was to investigate, in a Japanese population, relationships between CL/P or CPO and seven candidate genes (TGFB3, DLX3, PAX9, CLPTM1, TBX10, PVRL1, TBX22) that showed positive associations in other populations and are expressed in the oral/lip region in developing mice. We first searched for mutations in these genes among 112 CL/P and 16 CPO patients, and found a heterozygous missense mutation (640A > G, S214G) in exon 3 of PAX9 in two sibs with CL/P and their phenotypically normal mother from a Japanese family. A population-based case-control analysis and a family-based transmission disequilibrium test (TDT), using single nucleotide polymorphisms (SNPs), and two-SNP haplotypes of the genes, between the 112 CL/P cases with their parents and 192 controls indicated a significant association at one SNP site, IVS1 + 5321, in TGFB3 with a P-value of 0.0016. Population-based haplotyping revealed that the association was most significant for haplotype "A/A" consisting of IVS1 + 5321 and IVS1 - 1572; TDT also gave a P-value of 0.0252 in this haplotype.

Amino Acid Sequence↗
PubMed2005

Evaluation of two anti-gp91phox antibodies as immunoprobes for Nox family proteins: mAb 54.1 recognizes recombinant full-length Nox2, Nox3 and the C-terminal domains of Nox1-4 and cross-reacts with GRP 58.

Progress in the study of Nox protein expression has been impeded because of the paucity of immunological probes. The large subunit of human phagocyte flavocytochrome b558 (Cytb), gp91phox, is also the prototype member of the recently discovered family of NADPH oxidase (Nox) proteins. In this study, we have evaluated the use of two anti-gp91phox monoclonal antibodies, 54.1 and CL5, as immunoprobes for Nox family proteins. Sequence alignment of gp91phox with Nox1, Nox3 and Nox4 identified regions of the Nox proteins that correspond to the gp91phox epitopes recognized by mAb 54.1 and CL5. Antibody 54.1 produced positive immunoblots of recombinant C-terminal fragments of these homologous proteins expressed in E. coli. Furthermore, only mAb 54.1 recognized full-length murine and human Nox3 expressed in HEK-293 cells, in immunoblots of alkali-stripped or detergent-solubilized membranes. 54.1 recognized Nox3 expression-specific proteins with Mr 30,000, 50,000, 65,000 and 88,000 for the murine protein and Mr of 38,000-58,000, 90,000, 100,000-130,000 and a broad species of higher than 160,000 for the human protein. We conclude that mAb 54.1 can serve as a probe of Nox3 and possibly other Nox proteins, if precautions are taken to remove GRP 58 and other crossreactive membrane-associated or detergent-insoluble proteins from the sample to be probed.

Amino Acid Sequence↗
PubMed2005

Does donepezil treatment slow the progression of hippocampal atrophy in patients with Alzheimer's disease?

OBJECTIVE: The only approved pharmacological approach for the symptomatic treatment of Alzheimer's disease in Japan is the use of a cholinesterase inhibitor, donepezil hydrochloride. Recent in vivo and in vitro studies raise the possibility that cholinesterase inhibitors can slow the progression of Alzheimer's disease. The purpose of the present study was to determine whether donepezil has a neuroprotective effect in Alzheimer's disease by using the rate of hippocampal atrophy as a surrogate marker of disease progression. METHOD: In a prospective cohort study, 54 patients with Alzheimer's disease who received donepezil treatment and 93 control patients with Alzheimer's disease who never received anti-Alzheimer drugs underwent magnetic resonance imaging (MRI) twice at a 1-year interval. The annual rate of hippocampal atrophy of each subject was determined by using an MRI-based volumetric technique. Background characteristics, age, sex, disease duration, education, MRI interval, apolipoprotein E (APOE) genotype, and baseline Alzheimer's Disease Assessment Scale score were comparable between the treated and control groups. RESULTS: The mean annual rate of hippocampal volume loss among the treated patients (mean=3.82%, SD=2.84%) was significantly smaller than that among the control patients (mean=5.04%, SD=2.54%). Upon analysis of covariance, where those confounding variables (age, sex, disease duration, education, MRI interval, APOE genotype, and baseline Alzheimer's Disease Assessment Scale score) were entered into the model as covariates, the effect of donepezil treatment on hippocampal atrophy remained significant. CONCLUSIONS: Donepezil treatment slows the progression of hippocampal atrophy, suggesting a neuroprotective effect of donepezil in Alzheimer's disease.

Aged↗
PubMed2004

Oral administration of K-11706 inhibits GATA binding activity, enhances hypoxia-inducible factor 1 binding activity, and restores indicators in an in vivo mouse model of anemia of chronic disease.

Erythropoietin (Epo) gene expression is under the control of hypoxia-inducible factor 1 (HIF-1), and is negatively regulated by GATA. Interleukin 1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha), which increase the binding activity of GATA and inhibit Epo promoter activity, are increased in patients with anemia of chronic disease (ACD). We previously demonstrated the ability of K-7174 (a GATA-specific inhibitor), when injected intraperitoneally, to improve Epo production that had been inhibited by IL-1beta or TNF-alpha treatment. In the present study, we examined the ability of both K-11706, which inhibits GATA and enhances HIF-1 binding activity, and K-13144, which has no effect on GATA or HIF-1 binding activity, to improve Epo production following inhibition by IL-1beta or TNF-alpha in Hep3B cells in vitro and in an in vivo mouse assay. Oral administration of K-11706 reversed the decreases in hemoglobin and serum Epo concentrations, reticulocyte counts, and numbers of erythroid colony-forming units (CFU-Es) induced by IL-1beta or TNF-alpha. These results raise the possibility of using orally administered K-11706 for treating patients with ACD.

Administration, Oral↗
PubMed2004

Effectiveness of a clinical pathway for the diagnosis and treatment of dementia and for the education of families.

AIMS: Clinical pathways (CPs) are rarely used in the treatment of dementia. We established a CP for a series of medical practices (diagnosis, treatment, establishment of a care system, and caregiver education) for patients with dementia hospitalized for a three-week period, and evaluated its usefulness. METHODS: The length of hospital stay and hospital costs were compared between 23 consecutive patients with dementia hospitalized and treated using a CP and 20 controls treated by conventional medical practice without using a CP in a special ward for dementia patients. In the CP group, at the time of discharge, primary caregivers, physicians, and nurses were given a questionnaire to obtain their comments about the impression of treatment with the CP. RESULTS: The questionnaire survey indicated that the CP deepened the caregiver's understanding of the sequence of medical practices for the inpatient, the disorders of the inpatient, the treatment methods, and the methods for coping with the disorder. The CP was also useful for facilitating inpatient medical practice and promoting the establishment of a care system after discharge. The use of the CP significantly shortened the length of hospital stay and decreased hospital costs during hospitalization but increased the amount of work per day and made the medical staff feel that their freedom to choose medical procedures had been restricted. CONCLUSIONS: The CP was useful for execution of inpatient medical practices for patients with dementia.

Aged↗
PubMed2004

Production of two types of ice crystal-controlling proteins in Antarctic bacterium.

Pseudomonas fluorescens KUAF-68, which was isolated from Antarctica, had both ice-nucleating protein and antifreeze protein activities in the culture broth. We found that both proteins were separately produced based on the results of column chromatography, SDS-PAGE analysis and Southern hybridization. The activity of the ice-nucleating protein was stimulated by the addition of glycine (0.020 N%), whereas the activity of the antifreeze protein was stimulated by the addition of L-asparagine (0.025 N%). This is the first report on the production of two types of ice crystal-controlling proteins in one bacterial strain.

Journal Article↗
PubMed2004

Absence of mutations in the Wilms' tumor gene WT1 in primary breast cancer.

BACKGROUND: It was recently demonstrated that the WT1 gene was overexpressed in primary breast cancer and that the high expression levels of WT1 mRNA significantly correlated with poor prognosis. However, it remained undetermined whether or not the WT1 gene expressed in breast cancer had mutations. METHODS: Breast cancer tissues were obtained from 36 patients with breast cancer. WT1 genomic DNA was PCR-amplified and examined for mutations by direct sequencing. RESULTS: The sequencing analysis showed the absence of mutations through the whole 10 exons of the WT1 gene in the 36 cases of primary breast cancer. Two different single nucleotide polymorphisms (SNP) without an amino acid change (Pro42, C to T in exon 1, and/or Arg300, A to G in exon 7) were detected in the WT1 gene in 31 (86%) of the 36 cases examined. CONCLUSION: The results indicate that the wild-type WT1 gene plays an important role in the tumorigenesis of primary breast cancer.

Adult↗
PubMed2004

Overexpression of the Wilms' tumor gene W T1 in primary astrocytic tumors.

Expression of the Wilms' tumor gene W T1 in primary astrocytic tumors was examined using a quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) or immunohistochemistry. Real-time RT-PCR showed that W T1 mRNA was expressed at various levels in all of the 25 astrocytic tumors examined. Immunohistochemical analysis showed that W T1 protein was expressed in 5 of 6 low-grade astrocytic tumors (grade I-II) and all of 18 high-grade ones (grade III-IV), and that expression levels of W T1 protein in high-grade tumors were significantly higher than those in low-grade ones. W T1 protein was not detected in the normal glial cells contained in the tumor specimens. Furthermore, treatment with W T1 antisense oligomers specifically inhibited growth of glioblastoma cell lines, U87-MG, A172, and T-98G. These results may indicate that the W T1 gene plays an important role in tumorigenesis of primary astrocytic tumors.

Adolescent↗
PubMed2003

A GATA-specific inhibitor (K-7174) rescues anemia induced by IL-1beta, TNF-alpha, or L-NMMA.

Interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), or N(G)-monomethyl-L-arginine (L-NMMA) are increased in patients with chronic disease-related anemia. They increase the binding activity of GATA and inhibit erythropoietin (Epo) promoter activity. In this study, we examined the ability of K-7174 (a GATA-specific inhibitor) to improve Epo production when inhibited by treatment with IL-1beta, TNF-alpha, or L-NMMA. Epo protein production and promoter activity were induced in Hep3B cells with 1% O2. However, 15 U/ml IL-1beta, 220 U/ml TNF-alpha, or 10(-3) M L-NMMA inhibited Epo protein production and promoter activity, respectively. Addition of 10 microM K-7174 rescued these inhibitions of Epo protein production and promoter activity induced by IL-1beta, TNF-alpha, or L-NMMA, respectively. Electrophoretic mobility shift assays revealed that addition of K-7174 decreased GATA binding activity, which was increased with the addition of IL-1beta, TNF-alpha, or L-NMMA. Furthermore, intraperitoneal injection of mice with IL-1beta or TNF-alpha decreased the hemoglobin concentrations and reticulocyte counts. However, the addition of K-7174 reversed these effects. These results raise the possibility of using K-7174 as therapy to treat anemia.

Anemia↗
PubMed2003

Gene gun-based co-immunization of merozoite surface protein-1 cDNA with IL-12 expression plasmid confers protection against lethal Plasmodium yoelii in A/J mice.

The carboxyl-terminal region of the merozoite surface protein-1 (MSP1) is a leading candidate for a vaccine against malaria in the erythrocytic stage. In this study, we investigated the utility of interleukin-12 (IL-12) cDNA as an adjuvant for malaria DNA vaccine in a mouse challenge model. We found that co-immunization of expression plasmids encoding a C-terminal 15-kDa fragment of MSP1 (MSP1-15) with the IL-12 gene using a gene gun significantly increased the protective immunity against malaria as compared with MSP1-15 DNA immunization alone. Co-immunization of IL-12 DNA potentiated MSP1-15-specific T helper (Th)1-type immune responses as evaluated by in vivo antibody (Ab) responses and in vitro cytokine profiles. After the Plasmodium yoelii challenge, mice immunized with MSP1-15 plus IL-12 DNA showed a higher level of interferon gamma (IFN-gamma) production than did other groups of mice. In vivo neutralization of IFN-gamma or depletion of CD4(+) T cells completely abolished this protective immunity. Macrophages, but not nitric oxide (NO), were found to play an important role in this effector mechanism. The sera from mice in which the infection had been cleared by the vaccination showed strong protection against P. yoelii infection. Thus, in addition to cellular immune responses, Abs against parasites induced in the course of infection are essential for protection against P. yoelii. The results indicate that combined vaccination with DNA encoding antigenic peptides plus IL-12 DNA provides a strategy for improving the prophylactic efficacy of a vaccine for malaria infection.

Animals↗
PubMed2003

Suppression of erythropoietin gene expression by cadmium depends on inhibition of HIF-1, not stimulation of GATA-2.

Long-term exposure of rats to cadmium (Cd) resulted in a marked suppression of erythropoietin (Epo) mRNA expression in the kidneys and the development of severe anemia. A recent report revealed that Cd inhibited hypoxia-inducible factor 1 (HIF-1) binding activity and Epo mRNA expression and protein production. However, Epo gene expression is also regulated by transcription factor GATA-2, which binds to the GATA binding site of the Epo promoter. To elucidate the mechanism of suppression of Epo by Cd, the effect of Cd on GATA-2 function was studied. Epo promoter/enhancer luciferase constructs, one with the wild-type promoter and another with a promoter with a mutant GATA site, were transfected into Hep3B cells. No significant difference in Epo promoter activity in these two types of cells was observed in the presence of Cd. The binding activity of GATA-2 was not affected by Cd. This study showed that Cd inhibited HIF-1 binding activity and Epo promoter activity, and then suppressed Epo protein production. Inhibition of Epo gene expression by Cd depends on suppression of HIF-1 binding activity, not on alteration of GATA function.

Cadmium↗