Naoyuki Yamamoto

Calpis Co., Ltd., Tokyo, Tokyo-to, Japan

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Publications (12)26.34 Total impact

  • Article: Anti-influenza virus effects of both live and non-live Lactobacillus acidophilus L-92 accompanied by the activation of innate immunity.
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    ABSTRACT: The antiviral effects of both a live and non-live Lactobacillus acidophilus strain L-92 (L-92) were investigated by oral administration (10 mg/mouse per d) daily for 21 d in a mouse model infected intranasally with influenza virus (H1N1). Virus titres in the lung of mice administered either live or non-live L-92 cells daily for 15 d were repressed 6 d after virus infection compared with the control group. Natural killer (NK) activity in the orally administered non-live L-92 group was higher compared with that of the control group before virus infection and on day 6. In contrast, NK activity in the live L-92 group compared with the control group was not significantly changed on both days, but was significantly higher on day 1. In contrast, live L-92 showed a greater repression of virus proliferation compared with non-live L-92, 6 d after the infection. Live L-92 decreased the number of neutrophils in the lung and suppressed lung weight, leading to the consequent deterioration of consolidation scores of the lung. These results indicated that pretreatment of live or non-live L-92 cells had protective effects against influenza virus infection. Among the measured cytokines and chemokines, eotaxin, macrophage colony-stimulating factor, IL-1β, RANTES (regulated on activation, normal T cell expressed and secreted) and interferon-α were significantly increased in the lung: IL-17 was significantly increased in Peyer's patch of the live L-92 group compared with the control group. A mechanistic study suggested that the enhancement of NK activity in the lung caused by stimulating various antiviral cytokines and chemokines after the oral administration of L-92 cells might be important in protecting against virus infection.
    The British journal of nutrition 04/2013; · 3.45 Impact Factor
  • Article: Comparative analysis of proteolytic enzymes need for processing of antihypertensive peptides between Lactobacillus helveticus CM4 and DPC4571.
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    ABSTRACT: To understand high amount of production and detailed processing of antihypertensive peptides, Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), in Lactobacillus helveticus CM4 fermented milk, whole genome sequence of the CM4 strain was completed and compared to previously reported whole genome sequence of L. helveticus DPC4571. It revealed 2,028,493 bp of DNA sequence and encoding of 2174 open reading frames in the whole genome sequence with the highest homology to the genome sequence of L. helveticus DPC 4571. Comparative analysis focused on proteolytic enzymes between CM4 and DPC4571 strains revealed existence of 23 kinds of identical intracellular peptidase genes in both strains but no prtY type proteinase gene in DPC4571. Immunoblotting analysis with an antibody raised against the PrtY proteinase showed existence of the 45 kDa PrtY protein in CM4 but not in DPC4571 in the cell extracts. The cell wall-associated proteinase activity was higher in the CM4 than that in the DPC4571 throughout all fermentation period, and the amounts of VPP and IPP in CM4 and DPC4571 fermented milk were correlated with the proteinase activity on the cell wall. Moreover, slight difference of the β-casein hydrolysates by cell wall-associated extracellular proteinases between CM4 and DPC4571 cells was detected by a MALDI-TOF/TOF analysis. These results suggest that the extracellular proteinase activity might affect on the productivity of VPP and IPP in L. helveticus fermented milk and some peptidases might play important role in following precise processing to release VPP and IPP.
    Journal of Bioscience and Bioengineering 11/2012; · 1.79 Impact Factor
  • Article: Accumulation of ACE Inhibitory Tripeptides, Val-Pro-Pro and Ile-Pro-Pro, in Vascular Endothelial Cells.
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    ABSTRACT: The antihypertensive peptides, Val-Pro-Pro and Ile-Pro-Pro, were successfully detected in the aorta of spontaneously hypertensive rats after orally administering these peptides by a guanidine-thiocyanate treatment to prevent proteolysis. Cy3-labeled versions of both peptides were localized in the endothelial cells of arterial vessels in the rats. The accumulation of both peptides in the endothelial cells suggested in vivo inhibitory activity of the angiotensin I-converting enzyme.
    Bioscience Biotechnology and Biochemistry 09/2012; 76(9):1792-5. · 1.28 Impact Factor
  • Article: Transcriptional response of Lactobacillus acidophilus L-92 after attachment to epithelial Caco-2 cells.
    Sae Yanagihara, Tatsuhiko Hirota, Naoyuki Yamamoto
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    ABSTRACT: Transcriptome analysis showed that Lactobacillus acidophilus L-92 cells having anti-allergy effects on human up-regulated 41 genes involved permease, ABC transporter, proteinase and transcriptional regulator after attached to epithelial Caco-2 cells. Inversely, 37 genes were down-regulated, including ATP synthases, ABC transporters and transcriptional regulators.
    Journal of Bioscience and Bioengineering 07/2012; · 1.79 Impact Factor
  • Article: Repressive processing of antihypertensive peptides, Val-Pro-Pro and Ile-Pro-Pro, in Lactobacillus helveticus fermented milk by added peptides.
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    ABSTRACT: Lactobacillus helveticus can release the antihypertensive peptides, Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), from casein in fermented milk by a specific proteolytic system. To better understand the regulation of gene expression of the proteolytic enzymes thought to link to the processing of both antihypertensive peptides in L. helveticus, microarray analysis for whole gene expression in the presence and absence of added peptides in the fermented milk was studied. The productivity of both VPP and IPP in L. helveticus CM4 fermented milk was repressed by adding 2% quantity of Peptone as peptide mixture to the milk. Among the selected 13 amino acids, Gly, Ile, Leu, Phe, Met, Ser and Val were effective in the repression of the productivity of VPP and IPP in the fermented milk. The activity of the cell wall-associated proteinase, which may play a key role in the processing of the two antihypertensive peptides, was significantly repressed by the addition of the 2% quantity of Peptone into the fermented milk. By DNA microarray analysis it was found that prtH2 corresponding to the cell wall-associated proteinase gene, most of the endopeptidase genes such as pepE, pepO1, pepO2 and pepO3, most of the oligopeptide transporter genes, such as dppA2, dppB, dppC, dppD and dppF, most likely involved in the processing of VPP and IPP were down-regulated. These results suggest that amino acids released from milk peptides in the fermented milk might down-regulate the gene expressions of some of the proteolytic enzymes and may cause repression of the release of VPP and IPP in L. helveticus fermented milk.
    Journal of Bioscience and Bioengineering 05/2012; 114(2):133-7. · 1.79 Impact Factor
  • Article: Exposure to probiotic Lactobacillus acidophilus L-92 modulates gene expression profiles of epithelial Caco-2 cells.
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    ABSTRACT: To understand host gastrointestinal response after exposure to probiotic Lactobacillus acidophilus L-92, microarray analysis of cultured epithelial Caco-2 cells was performed. Of the 187 genes down-regulated after 4 h treatment with L-92, 25 were involved in RNA splicing; 12, in cell cycle; 8 were transcriptional regulators; 2 were involved in ubiquitin proteolysis; 2, in adhesion; 2, in meiosis; 2, in splicing; and 2 encoding cytokines. In the RNA splicing group, genes encoding small nuclear RNAs, nuclear pore complex interacting proteins, RNA binding motif proteins, and SMG1 homologs (phosphatidylinositol 3-kinase-related kinase) were identified. Among the only 13 genes up-regulated by the treatment, 5 were involved in histone structure, and 2 were involved in metabolism. Genes belonging to cell adhesion, transmembrane proteins, mitogen-activated protein kinase, immune response, DNA binding, inflammation, and protein synthesis groups were mainly up-regulated after 20 h of treatment, whereas no significantly down-regulated genes were observed. In the present transcriptome analysis, during the early stage of treatment (four hours of treatment) with L-92, genes involved in cell growth and cell meiosis were mainly repressed. During the late phase of treatment (20 h of treatment), the expression of the genes linked to cell adhesion activity and metabolism for cell growth was enhanced. From the present transcriptome analysis, we suggest that Caco-2 cells slow down cell death and turnover of RNA synthesis as an early response to L-92 treatment; at the late stage of treatment, the genes involved in cell proliferation, transcriptional activity, and apoptosis are activated.
    Journal of medicinal food 04/2012; 15(6):511-9. · 1.39 Impact Factor
  • Article: Characterization of adhesive molecule with affinity to Caco-2 cells in Lactobacillus acidophilus by proteome analysis.
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    ABSTRACT: The adhesive activities of eight Lactobacillus acidophilus strains toward intestinal epithelial Caco-2 cells were studied to understand the probiotic characteristics of the L. acidophilus L-92 strain. Most of the strains, including L-92, showed high adhesive activity; CP23 showed the lowest adhesive activity. CP23 was selected for comparative analysis of cell wall-associated proteins versus the L-92 strain. Cell wall-associated proteins extracted from L-92 and CP23 were subjected to two-dimensional electrophoresis, and major spots observed in the former were compared to the corresponding spots in the latter. To understand the effects of key components of L-92 on its adhesion to Caco-2 cells, 18 spots with stronger signals in L-92 than those in CP23 were identified by a MALDI-TOF/TOF of Ultraflex analysis. Among the identified proteins of L-92, surface-layer protein A (SlpA) was considered strongly involved in adhesion in the eight L. acidophilus strains. To study the importance of SlpA in the adhesion of L. acidophilus, the amounts of SlpA proteins in LiCl extracts of the eight strains were compared by SDSpolyacrylamide gel electrophoresis. As a result, the adhesive abilities of L. acidophilus strains to Caco-2 cells correlated closely to the amount of SlpA in the cells and the productivity of IL-12, an inflammatory cytokine, in all eight strains. These results strongly suggested that SlpA in L. acidophilus might play a key role in its attachment to Caco-2 cells and in the release of IL-12 from dendritic cells.
    Journal of Bioscience and Bioengineering 10/2011; 112(4):333-7. · 1.79 Impact Factor
  • Article: Release of antihypertensive peptides in miso paste during its fermentation, by the addition of casein.
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    ABSTRACT: Casein hydrolysate by Aspergillus oryzae protease has been developed to obtain two kinds of antihypertensive peptides, Val-Pro-Pro and Ile-Pro-Pro. In this study, casein miso paste was prepared by adding casein at various concentrations during miso paste fermentation in order to release angiotensin-I converting enzyme (ACE) inhibitory peptides. Increase of peptide concentration and ACE inhibitory activity in casein miso paste was observed and corresponded to the degradation of casein and soy bean proteins during fermentation for 7 days. ACE inhibitory activity of the casein miso paste was higher than that of the general (casein-free) miso paste after fermentation for 7 days. The levels of ACE inhibitory peptides, Val-Pro-Pro and Ile-Pro-Pro, were increased in the casein miso paste during the fermentation. Significant antihypertensive effects of casein miso paste compared to water and the general miso paste (P<0.05 and P<0.05) were confirmed in spontaneously hypertensive rats at a dosage of 1.8 g of the casein miso paste/kg of BW. Taken into account of minimum effective dosages of Val-Pro-Pro and Ile-Pro-Pro in previous clinical studies, these results suggest that casein miso paste might have the potential to control blood pressure in humans.
    Journal of Bioscience and Bioengineering 09/2009; 108(2):111-5. · 1.79 Impact Factor
  • Article: Study of the mechanism of antihypertensive peptides VPP and IPP in spontaneously hypertensive rats by DNA microarray analysis.
    Naoya Yamaguchi, Kyosuke Kawaguchi, Naoyuki Yamamoto
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    ABSTRACT: Many antihypertensive effects of angiotensin-I-converting enzyme (ACE) inhibitory peptides have been studied in spontaneously hypertensive rats (SHRs) and human, however, the mild actions of these peptides expressed by these consecutive uptakes are still not clear. Here, to understand the in vivo antihypertensive effects of well-characterized two peptides, Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), DNA microarray was used to analyze gene expression in SHRs fed these peptides for 5 days. By using an Affymetrix analyzer, gene profiling was performed in a target organ, the aorta, of SHRs after repeated administration of VPP and IPP for 5 days. The changes in gene expression were relatively mild; therefore, among the analyzed genes associated with blood pressure, those that showed changes over +/- 5% as compared to the control group were categorized as the renin angiotensin aldosterone system, vascular function, arachidonic acid system, blood coagulation system, and cytokines and growth factors. Significant and marked differences were detected for the endothelial nitric oxide synthase (eNOS) gene (1.89-fold, P<0.05) and the connexin 40 (gap junction 40) gene (2.81-fold, P<0.05). Administration of VPP and IPP led to a slight increase in the expression of the cyclooxigenase (COX-1) gene and a decrease in the expression of both the nuclear factor kappa B subunit (NF-kappaB) gene for vascular function and the peroxisome proliferator activator receptor gamma (PPARgamma) gene. Taken together, these results suggest that VPP and IPP function as ACE inhibitors in the aorta, where they may have a preventive role in cardiovascular function.
    European journal of pharmacology 08/2009; 620(1-3):71-7. · 2.59 Impact Factor
  • Article: Purification and identification of proteolytic enzymes from Aspergillus oryzae capable of producing the antihypertensive peptide Ile-Pro-Pro.
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    ABSTRACT: Two proteolytic enzymes capable of releasing the angiotensin I-converting enzyme (ACE) inhibitor Ile-Pro-Pro from casein were identified by purification of an Aspergillus oryzae extract by three-step column chromatography. First, proteins capable of producing Ile-Pro-Pro from beta-casein were eluted using a DEAE-sepharose FF column with a linear sodium chloride gradient. An endopeptidase capable of releasing Pro-Ile-Pro-Gln-Ser-Leu-Pro-Gln-Asn-Ile-Pro-Pro from Pro-Ile-Pro-Gln-Ser-Leu-Pro-Gln-Asn-Ile-Pro-Pro-Leu-Thr-Gln and an aminopeptidase producing Ile-Pro-Pro from Gln-Asn-Ile-Pro-Pro were separated from the resultant fraction using a hydroxyapatite column. Each active enzyme was then loaded onto a Develosil 300Diol gel filtration column for high performance liquid chromatography (HPLC) and purified to homogeneity. The endopeptidase had a molecular mass of approximately 46,000 Da and exhibited an N-terminal amino acid sequence identical to that of neutral protease I (NP I) of A. oryzae. Meanwhile, the aminopeptidase had a molecular mass of 36,000 Da and an N-terminal amino acid sequence similar to that of Leucine aminopeptidase (LAP), as reported in Aspergillus sojae and A. oryzae. The eluted endopeptidase and aminopeptidase were thus identified as NP I and LAP, respectively. Analysis of peptide production using synthetic proteins containing an Ile-Pro-Pro sequence showed that NP I processed the C-terminal end and LAP processed the N terminus to produce Ile-Pro-Pro. While Ile-Pro-Pro was successfully produced from casein by the addition of these two purified enzymes, it was not generated with the addition of only a single enzyme. Based on our experimental findings, we suggest that NP I and LAP are key proteolytic enzymes in the release of Ile-Pro-Pro from casein in A. oryzae.
    Journal of Bioscience and Bioengineering 07/2009; 107(6):615-9. · 1.79 Impact Factor
  • Article: Antihypertensive effect of casein hydrolysate in a placebo-controlled study in subjects with high-normal blood pressure and mild hypertension.
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    ABSTRACT: We describe a clinical trial to study the efficacy of a casein hydrolysate, prepared using an Aspergillus oryzae protease, containing the major angiotensin-I-converting enzyme inhibitory peptides Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP) in a single-blind, placebo-controlled study. A total of 131 volunteers with high-normal blood pressure and mild hypertension were randomly divided into four groups (n 32 or 33 in each group). Each volunteer was given two tablets containing four different dosages of VPP and IPP (VPP+IPP: 0, 1.8, 2.5 and 3.6 mg), daily for 6 weeks. A significant decrease in systolic blood pressure was observed at 6 weeks in the active group receiving 1.8 mg (P<0.01) VPP and IPP; in the active groups receiving either 2.5 mg or 3.6 mg, systolic blood pressure was decreased at both 3 weeks (P<0.05 and P<0.05) and 6 weeks (P<0.001 and P<0.0001) compared with systolic blood pressure measured before treatment. Changes in the systolic blood pressure after 6 weeks of treatment in the four groups were --1.7, --6.3, --6.7 and --10.1 mmHg, and these effects were dose dependent. In addition, a significant difference in systolic blood pressure between the placebo group and the VPP and IPP group receiving 3.6 mg was observed (P<0.001) by two-way ANOVA. The antihypertensive effect was greater in mildly hypertensive subjects (n 20 or 21 in each group) than in any of the other subjects. No significant change of diastolic blood pressure was observed for all the test groups, and no differences in diastolic blood pressure in the test sample groups compared with the placebo group were observed during the test period.
    British Journal Of Nutrition 07/2005; 94(1):84-91. · 3.01 Impact Factor
  • Article: Biogenic peptides and their potential use.
    Naoyuki Yamamoto, Masahiro Ejiri, Seiichi Mizuno
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    ABSTRACT: This paper reviews bioactive peptides, biogenic peptides, opioid peptides, immunostimulating peptides, mineral soluble peptides, antihypertensive peptides and antimicrobial peptides originating from food materials and enzymatic hydrolysis of proteins. Antihypertensive peptides are extensively reviewed and have been divided into angiotensin I-converting enzyme inhibitory peptides and others. These peptides are produced in the enzymatic hydrolysate of treated food materials such as milk, animal and fish meat, maize, wheat, soybeans and egg, and also from microbe-fermented products. Peptides with strong antihypertensive effects on spontaneously hypertensive rats are discussed and are divided into high and low angiotensin I-converting enzyme inhibitory activities. In addition, new topics from our studies on antihypertensive peptides are introduced. Efficacies of these peptides in clinical studies and differences with medicinal substances are summarized. Recent studies in this area shown the possibility of using biogenic peptides for improvements in treatment or prevention of hypertension.
    Current Pharmaceutical Design 02/2003; 9(16):1345-55. · 3.87 Impact Factor