Details of a Researcher - YAMAMOTO Sou

Papers - YAMAMOTO Sou

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Rapid and Integrated Bacterial Evolution Analysis unveils gene mutations and clinical risk of Klebsiella pneumoniae.

Kojiro Uemura, Toyotaka Sato, Soh Yamamoto, Noriko Ogasawara, Jirachaya Toyting, Kotaro Aoki, Akira Takasawa, Masayuki Koyama, Atsushi Saito, Takayuki Wada, Kaho Okada, Yurie Yoshida, Koji Kuronuma, Chie Nakajima, Yasuhiko Suzuki, Motohiro Horiuchi, Kenichi Takano, Satoshi Takahashi, Hirofumi Chiba, Shin-Ichi Yokota

Nature communications 16 ( 1 ) 2917 - 2917 2025.03 [International journal]

Bacteria continually evolve. Previous studies have evaluated bacterial evolution in retrospect, but this approach is based on only speculation. Cohort studies are reliable but require a long duration. Additionally, identifying which genetic mutations that have emerged during bacterial evolution possess functions of interest to researchers is an exceptionally challenging task. Here, we establish a Rapid and Integrated Bacterial Evolution Analysis (RIBEA) based on serial passaging experiments using hypermutable strains, whole-genome and transposon-directed sequencing, and in vivo evaluations to monitor bacterial evolution in a cohort for one month. RIBEA reveals bacterial factors contributing to serum and antimicrobial resistance by identifying gene mutations that occurred during evolution in the major respiratory pathogen Klebsiella pneumoniae. RIBEA also enables the evaluation of the risk for the progression and the development of invasive ability from the lung to blood and antimicrobial resistance. Our results demonstrate that RIBEA enables the observation of bacterial evolution and the prediction and identification of clinically relevant high-risk bacterial strains, clarifying the associated pathogenicity and the development of antimicrobial resistance at genetic mutation level.

Bacillaceae serine proteases and Streptomyces epsilon-poly-l-lysine synergistically inactivate Caliciviridae by inhibiting RNA genome release

Soh Yamamoto, Noriko Ogasawara, Yuka Sudo-Yokoyama, Sachiko Sato, Nozomu Takata, Nana Yokota, Tomomi Nakano, Kyoko Hayashi, Akira Takasawa, Mayumi Endo, Masako Hinatsu, Keitaro Yoshida, Toyotaka Sato, Satoshi Takahashi, Kenichi Takano, Takashi Kojima, Jun Hiraki, Shin-ich Yokota

Scientific Reports ( Springer Science and Business Media LLC ) 14 ( 1 ) 2024.07 [Refereed]

Authorship： Lead author

Abstract Human norovirus (HuNoV) is an enteric infectious pathogen belonging to the Caliciviridae family that causes occasional epidemics. Circulating alcohol-tolerant viral particles that are readily transmitted via food-borne routes significantly contribute to the global burden of HuNoV-induced gastroenteritis. Moreover, contact with enzymes secreted by other microorganisms in the environment can impact the infectivity of viruses. Hence, understanding the circulation dynamics of Caliciviridae is critical to mitigating epidemics. Accordingly, in this study, we screened whether environmentally abundant secretase components, particularly proteases, affect Caliciviridae infectivity. Results showed that combining Bacillaceae serine proteases with epsilon-poly-l-lysine (EPL) produced by Streptomyces—a natural antimicrobial—elicited anti-Caliciviridae properties, including against the epidemic HuNoV GII.4_Sydney_2012 strain. In vitro and in vivo biochemical and virological analyses revealed that EPL has two unique synergistic viral inactivation functions. First, it maintains an optimal pH to promote viral surface conformational changes to the protease-sensitive structure. Subsequently, it inhibits viral RNA genome release via partial protease digestion at the P2 and S domains in the VP1 capsid. This study provides new insights regarding the high-dimensional environmental interactions between bacteria and Caliciviridae, while promoting the development of protease-based anti-viral disinfectants.

Multilayered proteomics reveals that JAM-A promotes breast cancer progression via regulation of amino acid transporter LAT1.

Kazufumi Magara, Akira Takasawa, Kumi Takasawa, Tomoyuki Aoyama, Misaki Ota, Daisuke Kyuno, Yusuke Ono, Taro Murakami, Soh Yamamoto, Yuna Nakamori, Naoya Nakahashi, Goro Kutomi, Ichiro Takemasa, Tadashi Hasegawa, Makoto Osanai

Cancer science 2024.06 [Refereed] [International journal]

Recent studies have shown that transmembrane-type tight junction proteins are upregulated in various cancers compared with their levels in normal tissues and are involved in cancer progression, suggesting that they are potential therapeutic targets. Here, we demonstrated the expression profile and a novel role of junctional adhesion molecule-A (JAM-A) in breast cancer. Immunohistochemistry of surgical specimens showed that JAM-A was highly expressed from carcinoma in situ lesions, as in other adenocarcinomas, with higher expression in invasive carcinomas. High expression of JAM-A contributed to malignant aspects such as lymph node metastasis and lymphatic involvement positivity. In breast cancer cells, JAM-A expression status affects malignant potentials including proliferation and migration. Multilayered proteomics revealed that JAM-A interacts with the amino acid transporter LAT1 in breast cancer cells. JAM-A regulates the expression of LAT1 and interacts with it on the whole cell membrane, leading to enhanced amino acid uptake to promote tumor growth. Double high expression of JAM-A and LAT1 predicts poor prognosis in patients with breast cancer. Of note, an antibody against an extracellular domain of JAM-A suppressed the proliferation of breast cancer cells. Our findings indicate the possibility of JAM-A-targeted therapy ideally combined with LAT1-targeted therapy as a new therapeutic strategy against breast cancer.

The clarithromycin-binding proteins NIPSNAP1 and 2 regulate cytokine production through mitochondrial quality control.

Soh Yamamoto, Noriko Ogasawara, Yukari Mitsuhashi, Kenichi Takano, Shin-Ichi Yokota

Scientific reports 14 ( 1 ) 2354 - 2354 2024.01 [Refereed] [International journal]

Authorship： Lead author

The mechanism underlying the anti-inflammatory effect of macrolide antibiotics, such as clarithromycin (CAM), remains to be clarified. The CAM-binding proteins 4-nitrophenylphosphatase domain and non-neuronal synaptosomal associated protein 25 (SNAP25)-like protein homolog (NIPSNAP) 1 and 2 are involved in the immune response and mitochondrial homeostasis. However, the axis between CAM-NIPSNAP-mitochondria and Toll-like receptor (TLR) and their molecular mechanisms remain unknown. In this study, we sought to elucidate the relationship between mitochondrial homeostasis mediated by NIPSNAP1 and 2 and the immunomodulatory effect of CAM. NIPSNAP1 or 2 knockdown (KD) by RNA interference impaired TLR4-mediated interleukin-8 (IL-8) production. Similar impairment was observed upon treatment with mitochondrial function inhibitors. However, IL-8 secretion was not impaired in NIPSNAP1 and 2 individual knockout (KO) and double KO (DKO) cells. Moreover, the oxygen consumption rate (OCR) in mitochondria measured using a flex analyzer was significantly reduced in NIPSNAP1 or 2 KD cells, but not in DKO cells. CAM also dose-dependently reduced the OCR. These results indicate that CAM suppresses the IL-8 production via the mitochondrial quality control regulated by temporary functional inhibition of NIPSNAP1 and 2. Our findings provide new insight into the mechanisms underlying cytokine production, including the TLR-mitochondria axis, and the immunomodulatory effects of macrolides.

Affinity of β-Lactam Antibiotics for Neisseria gonorrhoeae Penicillin-Binding Protein 2 Having Wild, Cefixime-Reduced-Susceptible, and Cephalosporin (Ceftriaxone)-Resistant penA Alleles.

Yoshiki Hiyama, Soh Yamamoto, Toyotaka Sato, Noriko Ogasawara, Naoya Masumori, Satoshi Takahashi, Shin-Ichi Yokota

Microbial drug resistance (Larchmont, N.Y.) 2024.01 [Refereed] [International journal]

Authorship： Lead author

Multidrug-resistant Neisseria gonorrhoeae is a serious concern worldwide. Resistance to β-lactam antibiotics occurs through mutations in penicillin-binding proteins (PBPs), acquisition of β-lactamases, and alteration of antibiotic penetration. Mosaic structures of penA, which encodes PBP2, play a major role in resistance to β-lactams, especially cephalosporins. Ceftriaxone (CRO) is recognized as the only satisfiable antibiotic for the treatment of gonococcal infections; however, CRO-resistant isolates have emerged in the community. Here, we examined the affinity of β-lactam antibiotics for recombinant PBP2 in a competition assay using fluorescence-labeled penicillin. We found no or little difference in the affinities of penicillins and meropenem (MEM) for PBP2 from cefixime (CFM)-reduced-susceptible strain and cephalosporin-resistant strain. However, the affinity of cephalosporins, including CRO, for PBP2 from the cephalosporin-resistant strain was markedly lower than that for PBP2 from the CFM-reduced-susceptible-resistant strain. Notably, piperacillin (PIP) showed almost the same affinity for PBP2 from penicillin-susceptible, CFM-reduced-susceptible, and cephalosporin (including CRO)-resistant strains. Thus, PIP/tazobactam and MEM are candidate antibiotics for the treatment of CRO-resistant/multidrug-resistant N. gonorrhoeae.

Serotype replacement and an increase in non-encapsulated isolates among community-acquired infections of Streptococcus pneumoniae during post-vaccine era in Japan.

Shin-Ichi Yokota, Naoyuki Tsukamoto, Toyotaka Sato, Yasuo Ohkoshi, Soh Yamamoto, Noriko Ogasawara

IJID regions 8 105 - 110 2023.09 [Refereed] [International journal]

OBJECTIVES: It is feared that the serotype replacement of Streptococcus pneumoniae occurred by the introduction of pneumococcal vaccines as periodical inoculation leads to reduced efficacy of the approved vaccines and altered antimicrobial susceptibility. METHODS: We determined serotypes of 351 S. pneumoniae isolates collected at a commercial clinical laboratory in Hokkaido prefecture, Japan, from December 2018 to February 2019 by using the polymerase chain reaction procedure of the US Centers for Disease Control and Prevention. Antimicrobial susceptibility and resistance gene profiles were also examined. RESULTS: Vaccine coverage rates were 7.9% for 13-valent conjugate vaccine, and 32.5% for 23-valent polysaccharide vaccine, respectively. Non-typable strains were 19.7%. cpsA-positive isolates (group I), and null capsule clade (NCC)1, NCC2 and NCC3 (group II) comprised 31.3%, 28.4%, 32.8%, and 7.5% of the 69 non-typable strains, respectively. No penicillin-resistant/intermediate isolates were found; however, serotypes 35B and 15A/F showed low susceptibility to β-lactams. Only five strains (1.4%) were levofloxacin-resistant, and all were from the older persons, and three strains were serotype 35B. CONCLUSION: The progression of serotype replacement in non-invasive pneumococcal infections has occurred during the post-vaccine era in Japan, and non-encapsulated isolates, such as NCC, have increased. Antimicrobial susceptibility is not worsened.

High prevalence of colistin heteroresistance in specific species and lineages of Enterobacter cloacae complex derived from human clinical specimens.

Shota Fukuzawa, Toyotaka Sato, Kotaro Aoki, Soh Yamamoto, Noriko Ogasawara, Chie Nakajima, Yasuhiko Suzuki, Motohiro Horiuchi, Satoshi Takahashi, Shin-Ichi Yokota

Annals of clinical microbiology and antimicrobials 22 ( 1 ) 60 - 60 2023.07 [Refereed] [International journal]

BACKGROUND: Colistin (CST) is a last-line drug for multidrug-resistant Gram-negative bacterial infections. CST-heteroresistant Enterobacter cloacae complex (ECC) has been isolated. However, integrated analysis of epidemiology and resistance mechanisms based on the complete ECC species identification has not been performed. METHODS: Clinical isolates identified as "E. cloacae complex" by MALDI-TOF MS Biotyper Compass in a university hospital in Japan were analyzed. Minimum inhibitory concentrations of CST were determined by the broth microdilution method. The population analysis profiling (PAP) was performed for detecting the heteroresistant phenotype. The heat shock protein 60 (hsp60) cluster was determined from its partial nucleotide sequence. From the data of whole-genome sequencing, average nucleotide identity (ANI) for determining ECC species, multilocus sequence type, core genome single-nucleotide-polymorphism-based phylogenetic analysis were performed. phoPQ-, eptA-, and arnT-deleted mutants were established to evaluate the mechanism underlying colistin heteroresistance. The arnT mRNA expression levels were determined by reverse transcription quantitative PCR. RESULTS: Thirty-eight CST-resistant isolates, all of which exhibited the heteroresistant phenotype by PAP, were found from 138 ECC clinical isolates (27.5%). The prevalence of CST-resistant isolates did not significantly differ among the origin of specimens (29.0%, 27.8%, and 20.2% for respiratory, urine, and blood specimens, respectively). hsp60 clusters, core genome phylogeny, and ANI revealed that the CST-heteroresistant isolates were found in all or most of Enterobacter roggenkampii (hsp60 cluster IV), Enterobacter kobei (cluster II), Enterobacter chuandaensis (clusters III and IX), and Enterobacter cloacae subspecies (clusters XI and XII). No heteroresistant isolates were found in Enterobacter hormaechei subspecies (clusters VIII, VI, and III) and Enterobacter ludwigii (cluster V). CST-induced mRNA upregulation of arnT, which encodes 4-amino-4-deoxy-L-arabinose transferase, was observed in the CST-heteroresistant isolates, and it is mediated by phoPQ pathway. Isolates possessing mcr-9 and mcr-10 (3.6% and 5.6% of total ECC isolates, respectively) exhibited similar CST susceptibility and PAP compared with mcr-negative isolates. CONCLUSIONS: Significant prevalence (approximately 28%) of CST heteroresistance is observed in ECC clinical isolates, and they are accumulated in specific species and lineages. Heteroresistance is occurred by upregulation of arnT mRNA induced by CST. Acquisition of mcr genes contributes less to CST resistance in ECC.

Colistin-resistant bacteria poses few risks under physiological conditions

Soh Yamamoto, Masaru Usui, Noriko Ogasawara, Wataru Hayashi, Masato Suzuki, Noriyuki Nagano, Chie Nakajima, Yasuhiko Suzuki, Motohiro Horiuchi, Satoshi Takahashi, Shin-ichi Yokota, Yutaka Tamura, Toyotaka Sato

Research Square ( Research Square Platform LLC ) 2023.06 [Refereed]

Abstract Globally, 5.0 million people die annually from infections associated with antimicrobial-resistant bacteria, most commonly Escherichia coli¹. As colistin is a last-resort antibiotic for multidrug-resistant bacterial infections, the global spread of plasmid-mediated colistin resistance genes (mcr) gene is considered a major public health risk^2-4. However, the actual health risks of colistin resistance in hazardous bacteria have never been evaluated under physiological conditions. Here, we show that the fitness/virulence and colistin resistance of the pandemic multidrug-resistant E. coli clone ST131⁵ very depending on the acquired colistin resistance determinants and differ between physiological and in vitro conditions. The fitness/virulence of ST131 was unaffected by chromosomal-gene (pmrB) mutations or the acquisition of mcr-5-harbouring plasmids in mouse models. However, the acquisition of mcr-1- or mcr-3-harbouring plasmids attenuated fitness/virulence and promoted colistin susceptibility in human serum. We identified two virulence attenuation factors (vafA and vafB) on the pIncI2_mcr-1 plasmid that hijacked the ST131 transcriptome and inhibited nucleotide synthesis, attenuating colistin resistance. Our results demonstrate that colistin resistance poses much less of a threat than believed^6,7. We suggest that “nonresistance genes,” rather than resistance genes, are important antimicrobial resistance determinants for human health because they determine fitness/virulence and ultimately antimicrobial susceptibility under physiological conditions.

Rapid, simple, and cost-effective plaque assay for murine norovirus using microcrystalline cellulose.

Soh Yamamoto, Yuka Sudo-Yokoyama, Noriko Ogasawara, Shin-Ichi Yokota

Journal of virological methods 316 114715 - 114715 2023.06 [Refereed] [International journal]

Authorship： Lead author

Murine norovirus (MNV) is used widely as a practical alternative to human norovirus (HuNoV). Plaque-forming assays for MNV are important for developing therapeutic agents against HuNoV infections. Although agarose-overlay MNV assays have been reported, recent improvements in cellulose derivatives suggest that they could be optimized further, particularly with respect to improving the overlay material. To determine which overlay material is optimal for the MNV plaque assay, we compared four typical cellulose derivatives [microcrystalline cellulose (MCC), hydroxyethyl cellulose (HEC), hydroxypropyl methylcellulose (HPMC), and carboxymethyl cellulose (CMC)] with conventional agarose. We found that 3.5% (w/v) MCC-containing medium provided clear round-shaped plaques on RAW 264.7 cells 1 day after inoculation; the visibility of plaques was comparable with that of the original agarose-overlay assay. Removing residual MCC powder from the MCC-overlay assay before fixing was important for obtaining distinct plaques that are clearly countable. Finally, after calculating the plaque diameter as a percentage of well diameter, we found that 12- and 24-well plates were better than other plates for accurate plaque counting. The MCC-based MNV plaque assay is cost-effective and rapid, and produces plaques that are easy to count. Accurate virus quantification using this optimized plaque assay will enable reliable estimation of norovirus titers.

Invasive pulmonary aspergillosis with candidiasis: usefulness of molecular and ultrastructural morphological analysis on FFPE tissue for invasive fungal infections.

Yusaku Kubota, Akira Takasawa, Yusuke Ono, Tomoyuki Aoyama, Kumi Takasawa, Akinori Tada, Kazufumi Magara, Taro Murakami, Fuminori Daimon, Soh Yamamoto, Shota Sato, Yutaro Hiratsuka, Daisuke Kyuno, Makoto Osanai

Medical molecular morphology 56 ( 2 ) 1 - 8 2023.02 [Refereed] [Domestic journal]

Invasive pulmonary aspergillosis (IPA) is one of the most frequent forms of invasive fungal infections (IFI); however, it is often difficult to identify the pathogenic fungal species and to select appropriate treatments for patients with IFI including IPA. Here, we describe the detailed pathophysiology of an autopsy case of severe respiratory failure due to IPA with candidiasis. The patient developed severe respiratory failure after influenza infection and died, and the autopsy revealed a mixed disease of IPA with candidiasis. In this study, in addition to the routine pathological examination, we further examined formalin-fixed paraffin-embedded (FFPE) tissues by scanning electron microscopy (SEM) and partial genomic DNA sequencing. Although optical microscopy alone was insufficient to identify the pathogenic organisms, SEM clearly depicted the characteristic morphology of Aspergillus sp. and Candida sp. as closely overlapping in a nested fashion, providing evidence of mixed infection of both fungal species in a focal site. The technique using FFPE tissue in combination with ultrastructural observation by SEM, elemental analysis by SEM-EDX, and DNA sequencing is promising for analyzing the pathophysiology of IFI.

抗菌性物質・薬剤耐性/生体防御大腸菌ST131におけるmcr-1保有プラスミドの獲得による病原性減弱機構(Antimicrobial agents and resistance/Host defense Virulent attenuation mechanism by acquisition of mcr-1-harboring plasmid into Escherichia coli ST131)

佐藤豊孝, 山本聡, 小笠原徳子, 臼井優, 長野則之, 土井洋平, 堀内基広, 高橋聡, 横田伸一, 田村豊

日本細菌学雑誌 ( 日本細菌学会 ) 78 ( 1 ) 48 - 48 2023.02

A Hydroxypropyl Methylcellulose Plaque Assay for Human Respiratory Syncytial Virus.

Yuka Takumi-Tanimukai, Soh Yamamoto, Noriko Ogasawara, Sayaka Nakabayashi, Katsumi Mizuta, Keisuke Yamamoto, Ryo Miyata, Takuya Kakuki, Sumito Jitsukawa, Toyotaka Sato, Hiroyuki Tsutsumi, Takashi Kojima, Kenichi Takano, Shin-Ichi Yokota

Journal of virological methods 304 114528 - 114528 2022.03 [Refereed] [International journal]

Quantifying proliferative virus particles is one of the most important experimental procedures in virology. Compared with classical overlay materials, newly developed cellulose derivatives enable a plaque-forming assay to produce countable clear plaques easily. HEp-2 cells are widely used in plaque assays for human respiratory syncytial virus (RSV). It is crucial to use an overlay material to keep HEp-2 cell proliferation and prevent RSV particles from spreading over the fluid. Among four cellulose derivatives, carboxymethyl cellulose sodium salt (CMC), hydroxypropyl methylcellulose (HPMC), microcrystalline cellulose (MCC), and hydroxyethyl cellulose (HEC), we found that HPMC was the optimal overlay material because HPMC maintained HEp-2 cell proliferation and RSV infectivity. Although MCC was unsuitable for RSV, it assisted the plaque-forming by human metapneumovirus in TMPRSS2-expressing cells. Therefore, depending on the cells and viruses, it is necessary to use different overlay materials at varying concentrations.

Reduction of susceptibility to azoles and 5-fluorocytosine and growth acceleration in Candida albicans in glucosuria.

Yoshiki Hiyama, Toyotaka Sato, Satoshi Takahashi, Soh Yamamoto, Noriko Ogasawara, Naoya Masumori, Shin-Ichi Yokota

Diagnostic microbiology and infectious disease 102 ( 1 ) 115556 - 115556 2021.09 [Refereed] [International journal]

Diabetes mellitus is a chronic metabolic disease characterized by hyperglycemia and glucosuria, and is a risk factor for Candida infections. To reveal the potential effects of glucosuria on Candida spp., we investigated their growth and antifungal susceptibilities in normal human urine to which glucose was added. The viable cell numbers of Candida spp. were more than 10 fold higher in the urine added 3000 mg/dL glucose than in plain urine. In antifungal susceptibility, more than 80% of Candida albicans clinical isolates increased minimum inhibitory concentrations of azoles and 5-fluorocytosine with the addition of glucose, and exceeded their breakpoints. In most of the C. albicans clinical isolates, the mRNA expression of the azole resistance genes ERG11, CDR1, CDR2, and MDR1 in the presence of glucose in urine. These observations provide valuable information about the clinical course and therapeutic effects of azoles against C. albicans infections in patients with diabetes mellitus and hyperglucosuria.

An autophagy-related protein Becn2 regulates cocaine reward behaviors in the dopaminergic system.

Yoon-Jin Kim, Qingyao Kong, Soh Yamamoto, Kenta Kuramoto, Mei Huang, Nan Wang, Jung Hwa Hong, Tong Xiao, Beth Levine, Xianxiu Qiu, Yanxiang Zhao, Richard J Miller, Hongxin Dong, Herbert Y Meltzer, Ming Xu, Congcong He

Science advances 7 ( 8 ) 2021.02 [Refereed] [International journal]

Drug abuse is a foremost public health problem. Cocaine is a widely abused drug worldwide that produces various reward-related behaviors. The mechanisms that underlie cocaine-induced disorders are unresolved, and effective treatments are lacking. Here, we found that an autophagy-related protein Becn2 is a previously unidentified regulator of cocaine reward behaviors. Becn2 deletion protects mice from cocaine-stimulated locomotion and reward behaviors, as well as cocaine-induced dopamine accumulation and signaling, by increasing presynaptic dopamine receptor 2 (D2R) autoreceptors in dopamine neurons. Becn2 regulates D2R endolysosomal trafficking, degradation, and cocaine-induced behaviors via interacting with a D2R-bound adaptor GASP1. Inactivating Becn2 by upstream autophagy inhibitors stabilizes striatal presynaptic D2R, reduces dopamine release and signaling, and prevents cocaine reward in normal mice. Thus, the autophagy protein Becn2 is essential for cocaine psychomotor stimulation and reward through regulating dopamine neurotransmission, and targeting Becn2 by autophagy inhibitors is a potential strategy to prevent cocaine-induced behaviors.

Aberrant expression of junctional adhesion molecule-A contributes to the malignancy of cervical adenocarcinoma by interaction with poliovirus receptor/CD155.

Taro Murakami, Akira Takasawa, Kumi Takasawa, Taishi Akimoto, Tomoyuki Aoyama, Kazufumi Magara, Yuki Saito, Misaki Ota, Daisuke Kyuno, Soh Yamamoto, Tadashi Hasegawa, Tsuyoshi Saito, Makoto Osanai

Cancer science 112 ( 2 ) 906 - 917 2021.02 [Refereed] [International journal]

Recent studies have shown that aberrant expression of tight junction proteins (TJP) contributes to malignant potential of various cancers. In the present study, we investigated the expression of junctional adhesion molecule-A (JAM-A), one of the transmembrane TJP, in uterine cervical adenocarcinoma and the significance of its expression for malignancy. Immunohistochemistry on human surgical specimens showed that JAM-A was aberrantly expressed in neoplastic regions including adenocarcinoma in situ (AIS). Knockout of JAM-A significantly suppressed cell proliferation and colony-forming and migration abilities. We also showed that an antibody specific to an extracellular region of JAM-A reduced cell proliferation ability and that loss of JAM-A increased drug sensitivity of cervical adenocarcinoma cells. Based on a comprehensive proteome analysis, we found that poliovirus receptor (PVR/CD155) was regulated by JAM-A and formed a physical interaction with JAM-A. In human surgical specimens, PVR/CD155 expression was significantly correlated with some clinicopathological features and prognosis of cervical adenocarcinoma. Interestingly, most of the PVR/CD155-positive cases expressed a high level of JAM-A, and patients with the expression pattern of PVR/CD155 positive/JAM-A high had significantly shorter periods of relapse-free survival (P = .00964) and overall survival (P = .0204) than those for the other patients. Our observations suggest that aberrant expression of JAM-A promotes malignancy of uterine cervical adenocarcinoma by regulation of PVR/CD155, and JAM-A is therefore a potential therapeutic target for this malignancy.

Sitafloxacin has a potent activity for eradication of extended spectrum β-lactamase-producing fluoroquinolone-resistant Escherichia coli forming intracellular bacterial communities in uroepithelial cells.

Yoshiki Hiyama, Toyotaka Sato, Satoshi Takahashi, Soh Yamamoto, Yukari Fukushima, Chie Nakajima, Yasuhiko Suzuki, Shin-Ichi Yokota, Naoya Masumori

Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy 26 ( 12 ) 1272 - 1277 2020.12 [Refereed] [International journal]

INTRODUCTION: Eradication of asymptomatic bacteriuria (ASB) before urological procedures is important to reduce the risk for infectious complications after surgery. However, the appropriate regimen for antimicrobial treatment has not been fully determined. We experienced continuous (over 10 months) isolation of extended spectrum β-lactamase (ESBL)-producing fluoroquinolone-resistant Escherichia coli from urine of an asymptomatic patient. The four isolates obtained (SMESC1 to 4) were international high-risk clones of O25b:H4-ST131-H30R, and originated from one strain, as revealed by the whole genome sequences. Although the patient received meropenem (MEPM) and fosfomycin (FOM), to which the strains were susceptible before the urological procedures, they could not be eradicated. METHODS: To explore the reason for the continuous isolation even after MEPM and FOM administration, antimicrobial killing of adherent and/or intracellular bacterial communities (IBC) formed by coculture of the E. coli cells and T24 bladder epithelial cells were examined. RESULTS: FOM and levofloxacin did not decrease viable E. coli cells compared with gentamicin. MEPM partly decreased them, and sitafloxacin (STFX) decreased them most potently. These observations indicate that E. coli can survive in the urinary tract under antimicrobial administration, and some antimicrobials such as FOM and MEPM cannot eradicate E. coli in uroepithelial cells. Adhesion on urinary epithelial cells and/or IBC formation might result in continuous isolation from the urinary tract and recurrence of ASB and urinary tract infections. CONCLUSIONS: The present study suggests that STFX is a promising optional agent for the eradication of ESBL-producing fluoroquinolone-resistant E. coli in the urinary tract before urological procedures.

Structural analysis of the lipoteichoic acid anchor glycolipid: Comparison of methods for degradation of the glycerophosphate backbone polymer.

Tsukasa Shiraishi, Soh Yamamoto, Shin-Ichi Yokota

Journal of microbiological methods 166 105726 - 105726 2019.11 [Refereed] [International journal]

Comparison of measurements of anti-PLA2R antibodies in Japanese patients with membranous nephropathy using in-house and commercial ELISA.

Hajime Kaga, Atsushi Komatsuda, Soh Yamamoto, Tadashi Kikuchi, Mika Kamata, Akiko Sato, Masafumi Odaka, Shin-Ichi Yokota, Naoto Takahashi, Hideki Wakui

Clinical and experimental nephrology 23 ( 4 ) 465 - 473 2019.04 [Refereed] [Domestic journal]

BACKGROUND: The prevalence of antibodies against M-type anti-phospholipase A2 receptor (PLA2R) was reported to be ~ 70-80% in early studies on idiopathic membranous nephropathy (iMN) cohorts from Western countries, China, and Korea, and ~ 50% in recent studies on two Japanese iMN cohorts. METHODS: We developed an in-house enzyme-linked immunosorbent assay (ELISA) for the detection of anti-PLA2R antibodies, and examined sera from 217 patients with iMN, 22 patients with secondary MN (sMN), and 50 healthy individuals. All patients and healthy individuals were Japanese. The relationships between levels of anti-PLA2R antibodies and clinical parameters were analyzed. Serum samples were also tested using a standardized commercial ELISA (Euroimmun, Germany). RESULTS: In our ELISA, OD values greater than the mean + 3 standard deviation of healthy subjects were considered to be positive for anti-PLA2R antibodies. Of the patients with iMN, 33.6% (73/217) were positive, but all sMN patients were negative. Our ELISA and the Euroimmun ELISA had a high concordance (93.5%). The proportion of patients with nephrotic syndrome was significantly higher in anti-PLA2R antibody-positive patients than in antibody-negative patients (65.8 vs. 37.5%, P < 0.001). Levels of anti-PLA2R antibodies were significantly correlated with levels of urinary protein and serum albumin (P = 0.004 and P < 0.001, respectively). CONCLUSIONS: The prevalence of anti-PLA2R antibodies in our Japanese iMN cohort was lower than that in the previous studies from other countries and other Japanese institutes. The low prevalence of antibodies may be related with the characteristics of enrolled patients with mild proteinuria and undetectable antibody levels.

緑膿菌はリポ多糖の菌体外放出量が多く、高菌量下でコリスチンの抗菌活性が減弱する

横田伸一, 袴田浩, 山本聡, 佐藤豊孝, 白石宗

緑膿菌感染症研究会講演記録 ( 緑膿菌感染症研究会 ) 52回 52 - 54 2018.10

淋菌に対するpiperacillinとtazobactam/piperacillinの薬剤感受性の検討

桧山佳樹, 高橋聡, 佐藤豊孝, 山本聡, 品川雅明, 横田伸一, 舛森直哉

日本性感染症学会誌 ( (一社)日本性感染症学会 ) 29 ( 2 ) 236 - 236 2018.10

乳酸桿菌の対数期に膜小胞上に局在するリポテイコ酸

白石宗, 横田伸一, 佐藤耶舞羽, 伊藤利章, 吹谷智, 山本聡, 佐藤豊孝, 横田篤

日本乳酸菌学会誌 ( 日本乳酸菌学会 ) 29 ( 2 ) 116 - 116 2018.07

Autophagy Differentially Regulates Insulin Production and Insulin Sensitivity.

Soh Yamamoto, Kenta Kuramoto, Nan Wang, Xiaolei Situ, Medha Priyadarshini, Weiran Zhang, Jose Cordoba-Chacon, Brian T Layden, Congcong He

Cell reports ( Elsevier B.V. ) 23 ( 11 ) 3286 - 3299 2018.06 [Refereed] [International journal]

Authorship： Lead author

Autophagy, a stress-induced lysosomal degradative pathway, has been assumed to exert similar metabolic effects in different organs. Here, we establish a model where autophagy plays different roles in insulin-producing β cells versus insulin-responsive cells, utilizing knockin (Becn1F121A) mice manifesting constitutively active autophagy. With a high-fat-diet challenge, the autophagy-hyperactive mice unexpectedly show impaired glucose tolerance, but improved insulin sensitivity, compared to mice with normal autophagy. Autophagy hyperactivation enhances insulin signaling, via suppressing ER stress in insulin-responsive cells, but decreases insulin secretion by selectively sequestrating and degrading insulin granule vesicles in β cells, a process we term "vesicophagy." The reduction in insulin storage, insulin secretion, and glucose tolerance is reversed by transient treatment of autophagy inhibitors. Thus, β cells and insulin-responsive tissues require different autophagy levels for optimal function. To improve insulin sensitivity without hampering secretion, acute or intermittent, rather than chronic, activation of autophagy should be considered in diabetic therapy development.

Release of large amounts of lipopolysaccharides from Pseudomonas aeruginosa cells reduces their susceptibility to colistin.

Shin-Ichi Yokota, Hiroshi Hakamada, Soh Yamamoto, Toyotaka Sato, Tsukasa Shiraishi, Masaaki Shinagawa, Satoshi Takahashi

International journal of antimicrobial agents 51 ( 6 ) 888 - 896 2018.06 [Refereed] [International journal]

Pseudomonas aeruginosa is an important etiological agent of opportunistic infections. Injectable colistin is available as a last-line treatment option for multidrug-resistant P. aeruginosa infections. When cells were inoculated at a high number, colistin-susceptible P. aeruginosa grew on agar medium containing colistin at a concentration 10-fold higher than the minimum inhibitory concentration without acquiring colistin resistance. This study examined the responsible mechanism for growth in the presence of a high concentration of colistin. Cell wash fluid derived from P. aeruginosa efficiently reduced colistin antimicrobial activity. This reduction was mediated by lipopolysaccharide (LPS) in the wash fluid. Extracellular LPS inhibited colistin activity more effectively than cell-bound LPS in fixed cells. Cell wash fluids from Escherichia coli and Acinetobacter baumannii also reduced colistin activity; however, they were less potent than those from P. aeruginosa. The amount of LPS in cell wash fluid from P. aeruginosa was approximately 10-fold higher than that in fluid from E. coli or A. baumannii. In conclusion, cell-free LPS derived from bacterial cells inhibited the antimicrobial activity of colistin, and this effect was greatest for P. aeruginosa. Thus, large amounts of broken and dead cells of P. aeruginosa at infection foci will reduce the effectiveness of colistin, even against cells that have not yet acquired resistance.

Evaluation of consistency in quantification of gene copy number by real-time reverse transcription quantitative polymerase chain reaction and virus titer by plaque-forming assay for human respiratory syncytial virus.

Keisuke Yamamoto, Noriko Ogasawara, Soh Yamamoto, Kenichi Takano, Tsukasa Shiraishi, Toyotaka Sato, Hiroyuki Tsutsumi, Tetsuo Himi, Shin-Ichi Yokota

Microbiology and immunology 62 ( 2 ) 90 - 98 2018.02 [Refereed] [International journal]

The plaque-forming assay is the standard technique for determining viral titer, and a critical measurement for investigating viral replication. However, this assay is highly dependent on experimental technique and conditions. In the case of human respiratory syncytial virus (RSV) in particular, it can be difficult to objectively confirm the accuracy of plaque-forming assay because the plaques made by RSV are often small and unclear. In recent studies, RT-qPCR methods have emerged as a supportive procedure for assessment of viral titer, yielding highly sensitive and reproducible results. In this report, we compare the viral replication, as determined by plaque-forming assay, and the copy numbers of RSV genes NS1, NS2, N, and F, as determined by RT-qPCR. Two real-time PCR systems, SYBR Green and TaqMan probe, gave highly similar results for measurement of copy numbers of RSV N genes of virus subgroups A. We determined the RSV gene copy numbers in the culture cell supernatant and cell lysate measured at various multiplicities of infection. We found that copy number of the RSV N gene in the culture supernatant and cell lysate was highly correlated with plaque-forming units. In conclusion, RT-qPCR measurement of RSV gene copy number was highly dependent on viral titer, and the detailed comparison between each gene copy number and virus titer should be useful and supportive in confirming RSV plaque-forming assay and virus dynamics. The technique may also be used to estimate the amount of RSV present in clinical specimens.

Lipoteichoic acids are embedded in cell walls during logarithmic phase, but exposed on membrane vesicles in Lactobacillus gasseri JCM 1131T

Shiraishi T, Yokota, S, Sato Y, Ito T, Fukiya S, Yamamoto S, Sato T, Yokota A

Beneficial Microbes 9 ( 4 ) 653 - 662 2018 [Refereed]

Novel antimicrobial activities of a peptide derived from a Japanese soybean fermented food, Natto, against Streptococcus pneumoniae and Bacillus subtilis group strains.

Manabu Kitagawa, Tsukasa Shiraishi, Soh Yamamoto, Ryosuke Kutomi, Yasuo Ohkoshi, Toyotaka Sato, Hideki Wakui, Hideaki Itoh, Atsushi Miyamoto, Shin-Ichi Yokota

AMB Express ( BIOMED CENTRAL LTD ) 7 ( 1 ) 127 - 127 2017.12 [Refereed] [International journal]

We recently isolated a tumoricidal peptide from Natto, a Japanese traditional fermented food. In the present study, antimicrobial activity of the Natto peptide was examined. The peptide consisted of 45 amino acid residues, and its structure was predicted to be rich in α-helix. It excreted antimicrobial activity only against Streptococcus pneumoniae and Bacillus subtilis group (B. subtilis, Bacillus pumilus, and Bacillus licheniformis). Lesser antimicrobial activity was observed for Streptococcus species other than S. pneumoniae. Hemolysate or hemin was required for the antimicrobial activity of the peptide. The Natto peptide damages the cell membrane of B. subtilis. On the other hand, chain morphology was induced in S. pneumoniae, which is naturally diplococcus, during the early phases of the Natto peptide treatment; following that the cells were rapidly lysed. This suggested that the Natto peptide displayed a novel narrow spectrum of bactericidal activity and inhibited cell separation during cell division of S. pneumoniae.

A Becn1 mutation mediates hyperactive autophagic sequestration of amyloid oligomers and improved cognition in Alzheimer's disease.

Altea Rocchi, Soh Yamamoto, Tabitha Ting, Yuying Fan, Katherine Sadleir, Yigang Wang, Weiran Zhang, Sui Huang, Beth Levine, Robert Vassar, Congcong He

PLoS genetics ( Public Library of Science ) 13 ( 8 ) e1006962 2017.08 [Refereed] [International journal]

Impairment of the autophagy pathway has been observed during the pathogenesis of Alzheimer's disease (AD), a neurodegenerative disorder characterized by abnormal deposition of extracellular and intracellular amyloid β (Aβ) peptides. Yet the role of autophagy in Aβ production and AD progression is complex. To study whether increased basal autophagy plays a beneficial role in Aβ clearance and cognitive improvement, we developed a novel genetic model to hyperactivate autophagy in vivo. We found that knock-in of a point mutation F121A in the essential autophagy gene Beclin 1/Becn1 in mice significantly reduces the interaction of BECN1 with its inhibitor BCL2, and thus leads to constitutively active autophagy even under non-autophagy-inducing conditions in multiple tissues, including brain. Becn1F121A-mediated autophagy hyperactivation significantly decreases amyloid accumulation, prevents cognitive decline, and restores survival in AD mouse models. Using an immunoisolation method, we found biochemically that Aβ oligomers are autophagic substrates and sequestered inside autophagosomes in the brain of autophagy-hyperactive AD mice. In addition to genetic activation of autophagy by Becn1 gain-of-function, we also found that ML246, a small-molecule autophagy inducer, as well as voluntary exercise, a physiological autophagy inducer, exert similar Becn1-dependent protective effects on Aβ removal and memory in AD mice. Taken together, these results demonstrate that genetically disrupting BECN1-BCL2 binding hyperactivates autophagy in vivo, which sequestrates amyloid oligomers and prevents AD progression. The study establishes new approaches to activate autophagy in the brain, and reveals the important function of Becn1-mediated autophagy hyperactivation in the prevention of AD.

マクロライド作用機序クラリスロマイシンの炎症反応修飾作用の分子機構の解明気道上皮細胞のクラリスロマイシン結合タンパク質の同定と機能解析

横田伸一, 山本聡, 小笠原徳子, 植村知加, 高谷芳明, 伊藤英晃, 山本圭佑, 白石宗, 佐藤豊孝, 氷見徹夫

The Japanese Journal of Antibiotics ( (公財)日本感染症医薬品協会 ) 70 ( Suppl.A ) 60 - 64 2017.03

ウイルス、細菌、真菌クラリスロマイシンは気道上皮細胞でRSウイルスによって誘導されるインターフェロンの産生をIRF-3を介して調整する

山本圭佑, 小笠原徳子, 山本聡, 堤裕幸, 氷見徹夫, 横田伸一

The Japanese Journal of Antibiotics ( (公財)日本感染症医薬品協会 ) 70 ( Suppl.A ) 19 - 24 2017.03

患者の手術で採取した鼻粘膜から作製したhTERT導入鼻粘膜上皮細胞(hTERT-HNEC)、肺胞上皮由来細胞株(A549)、ヒト気道上皮細胞株(BEAS-2B)を用い、ヒト気道上皮細胞における急性呼吸器ウイルス感染症に対するクラリスロマイシン(CAM)の効果と、CAMのもつ免疫調節効果のメカニズムを調べるため各種検討した。RSウイルス(RSV)感染のCAMの影響を調べ、CAMがRSV増殖に影響を与えないことが示唆された。hTERT-HNEC、A549、BEAS-2Bなどの気道上皮細胞においてPoly:C処置、RSV感染で誘導されるIFN-β、IFN-λがCAMにより強く抑制された。宿主の自然免疫に関わる転写因子IRF、NF-κB、AP-1の結合領域を含むプロモーター活性化がCAMにより強く抑制された。

NIP-SNAP-1 and -2 mitochondrial proteins are maintained by heat shock protein 60.

Soh Yamamoto, Tomoya Okamoto, Noriko Ogasawara, Shin Hashimoto, Tsukasa Shiraishi, Toyotaka Sato, Keisuke Yamamoto, Hiroyuki Tsutsumi, Kenichi Takano, Testuo Himi, Hideaki Itoh, Shin-Ichi Yokota

Biochemical and biophysical research communications ( ACADEMIC PRESS INC ELSEVIER SCIENCE ) 483 ( 3 ) 917 - 922 2017.02 [Refereed] [International journal]

Authorship： Lead author

NIP-SNAP-1 and -2 are ubiquitous proteins thought to be associated with maintenance of mitochondrial function, neuronal transmission, and autophagy. However, their physiological functions remain largely unknown. To elucidate their functional importance, we screened for proteins that interact with NIP-SNAP-1 and -2, resulting in identification of HSP60 and P62/SQSTM1 as binding proteins. NIP-SNAP-1 and -2 localized in the mitochondrial inner membrane space, whereas HSP60 localized in the matrix. Native gel electrophoresis and filter trap assays revealed that human HSP60 prevented aggregation of newly synthesized NIP-SNAP-2 in an in vitro translation system. Moreover, expression levels of NIP-SNAP-1 and -2 in cells were decreased by knockdown of HSP60, but not HSP10. These findings indicate that HSP60 promotes folding and maintains the stability of NIP-SNAP-1 and -2.

Mitochondrial proteins NIP-SNAP-1 and -2 are a target for the immunomodulatory activity of clarithromycin, which involves NF-κB-mediated cytokine production.

Soh Yamamoto, Noriko Ogasawara, Keisuke Yamamoto, Chika Uemura, Yoshiaki Takaya, Tsukasa Shiraishi, Toyotaka Sato, Shin Hashimoto, Hiroyuki Tsutsumi, Kenichi Takano, Tetsuo Himi, Shin-Ichi Yokota

Biochemical and biophysical research communications ( ACADEMIC PRESS INC ELSEVIER SCIENCE ) 483 ( 3 ) 911 - 916 2017.02 [Refereed] [International journal]

Authorship： Lead author

Macrolide antibiotics have immunomodulatory activities, including suppression of cytokine production, cell adhesion molecule expression, and mucin production. These immunomodulatory activities improve the symptoms of respiratory diseases associated with chronic inflammation. However, the underlying molecular mechanism(s) is not well understood yet. To address this, we prepared clarithromycin (CAM)-conjugated Sepharose and examined bound cellular proteins by proteome analysis. We identified mitochondrial proteins 4-nitrophenylphosphatase domain and non-neuronal synaptosomal associated protein 25-like protein homolog (NIP-SNAP)-1 and -2 and very long-chain acyl-CoA dehydrogenase (VLCAD) as CAM-binding proteins. Production of proinflammatory cytokines (IL-8 and IL-6) induced by lipopolysaccharides (LPSs) and Pam3-CSK4 in human epithelial cell lines BEAS-2B and T24 were suppressed by knockdown of NIP-SNAP-1 or -2, and partly by knockdown of VLCAD. Also, knockdown of NIP-SNAP-1 or -2 in various cell lines suppressed LPS-induced expression of IL-8 and IL-6 mRNA and NF-κB activity. Thus, CAM suppresses NF-κB-mediated proinflammatory cytokine production by interacting with mitochondrial proteins, NIP-SNAP-1 and -2.

タゾバクタム/ピペラシリン耐性大腸菌の耐性機構の解析

鈴木裕樹, 佐藤豊孝, 山本聡, 小笠原徳子, 白石宗, 品川雅明, 高橋聡, 横田伸一

日本細菌学雑誌 ( 日本細菌学会 ) 72 ( 1 ) 138 - 138 2017.02

Tigecycline Nonsusceptibility Occurs Exclusively in Fluoroquinolone-Resistant Escherichia coli Clinical Isolates, Including the Major Multidrug-Resistant Lineages O25b:H4-ST131-H30R and O1-ST648.

Toyotaka Sato, Yuuki Suzuki, Tsukasa Shiraishi, Hiroyuki Honda, Masaaki Shinagawa, Soh Yamamoto, Noriko Ogasawara, Hiroki Takahashi, Satoshi Takahashi, Yutaka Tamura, Shin-Ichi Yokota

Antimicrobial agents and chemotherapy ( AMER SOC MICROBIOLOGY ) 61 ( 2 ) 2017.02 [Refereed] [International journal]

Tigecycline (TGC) is a last-line drug for multidrug-resistant Enterobacteriaceae We investigated the mechanism(s) underlying TGC nonsusceptibility (TGC resistant/intermediate) in Escherichia coli clinical isolates. The MIC of TGC was determined for 277 fluoroquinolone-susceptible isolates (ciprofloxacin [CIP] MIC, <0.125 mg/liter) and 194 fluoroquinolone-resistant isolates (CIP MIC, >2 mg/liter). The MIC50 and MIC90 for TGC in fluoroquinolone-resistant isolates were 2-fold higher than those in fluoroquinolone-susceptible isolates (MIC50, 0.5 mg/liter versus 0.25 mg/liter; MIC90, 1 mg/liter versus 0.5 mg/liter, respectively). Two fluoroquinolone-resistant isolates (O25b:H4-ST131-H30R and O125:H37-ST48) were TGC resistant (MICs of 4 and 16 mg/liter, respectively), and four other isolates of O25b:H4-ST131-H30R and an isolate of O1-ST648 showed an intermediate interpretation (MIC, 2 mg/liter). No TGC-resistant/intermediate strains were found among the fluoroquinolone-susceptible isolates. The TGC-resistant/intermediate isolates expressed higher levels of acrA and acrB and had lower intracellular TGC concentrations than susceptible isolates, and they possessed mutations in acrR and/or marR The MICs of acrAB-deficient mutants were markedly lower (0.25 mg/liter) than those of the parental strain. After continuous stepwise exposure to CIP in vitro, six of eight TGC-susceptible isolates had reduced TGC susceptibility. Two of them acquired TGC resistance (TGC MIC, 4 mg/liter) and exhibited expression of acrA and acrB and mutations in acrR and/or marR In conclusion, a population of fluoroquinolone-resistant E. coli isolates, including major extraintestinal pathogenic lineages O25b:H4-ST131-H30R and O1-ST648, showed reduced susceptibility to TGC due to overexpression of the efflux pump AcrAB-TolC, leading to decreased intracellular concentrations of the antibiotics that may be associated with the development of fluoroquinolone resistance.

日本のダイズ発酵食品である納豆由来ペプチドの新規の抗菌活性(Novel antimicrobial activities of a peptide derived from a Japanese soy-bean fermented food, Natto)

北川学, 白石宗, 山本聡, 久富亮佑, 佐藤豊孝, 小笠原徳子, 宮本篤, 横田伸一

日本細菌学雑誌 ( 日本細菌学会 ) 72 ( 1 ) 145 - 145 2017.02

Mechanism of Reduced Susceptibility to Fosfomycin in Escherichia coli Clinical Isolates.

Yasuo Ohkoshi, Toyotaka Sato, Yuuki Suzuki, Soh Yamamoto, Tsukasa Shiraishi, Noriko Ogasawara, Shin-Ichi Yokota

BioMed research international ( HINDAWI LTD ) 2017 5470241 - 5470241 2017 [Refereed] [International journal]

In recent years, multidrug resistance of Escherichia coli has become a serious problem. However, resistance to fosfomycin (FOM) has been low. We screened E. coli clinical isolates with reduced susceptibility to FOM and characterized molecular mechanisms of resistance and reduced susceptibility of these strains. Ten strains showing reduced FOM susceptibility (MIC ≥ 8 μg/mL) in 211 clinical isolates were found and examined. Acquisition of genes encoding FOM-modifying enzyme genes (fos genes) and mutations in murA that underlie high resistance to FOM were not observed. We examined ability of FOM incorporation via glucose-6-phosphate (G6P) transporter and sn-glycerol-3-phosphate transporter. In ten strains, nine showed lack of growth on M9 minimum salt agar supplemented with G6P. Eight of the ten strains showed fluctuated induction by G6P of uhpT that encodes G6P transporter expression. Nucleotide sequences of the uhpT, uhpA, glpT, ptsI, and cyaA shared several deletions and amino acid mutations in the nine strains with lack of growth on G6P-supplemented M9 agar. In conclusion, reduction of uhpT function is largely responsible for the reduced sensitivity to FOM in clinical isolates that have not acquired FOM-modifying genes or mutations in murA. However, there are a few strains whose mechanisms of reduced susceptibility to FOM are still unclear.

Pathogenic Lineage of mcr-Negative Colistin-Resistant Escherichia coli, Japan, 2008-2015.

Toyotaka Sato, Akira Fukuda, Yuuki Suzuki, Tsukasa Shiraishi, Hiroyuki Honda, Masaaki Shinagawa, Soh Yamamoto, Noriko Ogasawara, Masaru Usui, Hiroki Takahashi, Satoshi Takahashi, Yutaka Tamura, Shin-Ichi Yokota

Emerging infectious diseases ( CENTERS DISEASE CONTROL ) 22 ( 12 ) 2223 - 2225 2016.12 [Refereed] [International journal]

Clarithromycin prevents human respiratory syncytial virus-induced airway epithelial responses by modulating activation of interferon regulatory factor-3.

Keisuke Yamamoto, Soh Yamamoto, Noriko Ogasawara, Kenichi Takano, Tsukasa Shiraishi, Toyotaka Sato, Ryo Miyata, Takuya Kakuki, Ryuta Kamekura, Takashi Kojima, Hiroyuki Tsutsumi, Tetsuo Himi, Shin-Ichi Yokota

Pharmacological research ( ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD ) 111 804 - 814 2016.09 [Refereed] [International journal]

Macrolide antibiotics exert immunomodulatory activity by reducing pro-inflammatory cytokine production by airway epithelial cells, fibroblasts, vascular endothelial cells, and immune cells. However, the underlying mechanism of action remains unclear. Here, we examined the effect of clarithromycin (CAM) on pro-inflammatory cytokine production, including interferons (IFNs), by primary human nasal epithelial cells and lung epithelial cell lines (A549 and BEAS-2B cells) after stimulation by Toll-like receptor (TLR) and RIG-I-like receptor (RLR) agonists and after infection by human respiratory syncytial virus (RSV). CAM treatment led to a significant reduction in poly I:C- and RSV-mediated IL-8, CCL5, IFN-β and -λ production. Furthermore, IFN-β promoter activity (activated by poly I:C and RSV infection) was significantly reduced after treatment with CAM. CAM also inhibited IRF-3 dimerization and subsequent translocation to the nucleus. We conclude that CAM acts a crucial modulator of the innate immune response, particularly IFN production, by modulating IRF-3 dimerization and subsequent translocation to the nucleus of airway epithelial cells. This newly identified immunomodulatory action of CAM will facilitate the discovery of new macrolides with an anti-inflammatory role.

Measles Virus Genotype D Wild Strains Suppress Interferon-Stimulated Gene Expression More Potently than Laboratory Strains in SiHa Cells.

Masaru Jinushi, Soh Yamamoto, Noriko Ogasawara, Hideki Nagano, Shin Hashimoto, Hiroyuki Tsutsumi, Tetsuo Himi, Shin-Ichi Yokota

Viral immunology ( MARY ANN LIEBERT, INC ) 29 ( 5 ) 296 - 306 2016.06 [Refereed] [International journal]

Changes in interferon (IFN)-stimulated gene (ISG) expression in cells infected with measles virus (MeV), four wild strains (belonging to different genotypes), and the laboratory strain Edmonston were examined. ISGs [MxA, 2'-5'-oligoadenylate synthetase, and interferon regulatory factor-1] were upregulated in an MeV-infection-induced manner and in an IFN-induced manner. In MeV-infected SiHa cell lines, the MeV infection-induced expression levels were in the order of A>H1>D8>D5>D3. On the other hand, all infected cell lines abolished type I and III IFN-induced ISG expression. However, partial type II IFN-mediated induction was observed in the MeV-infected cells. The wild strain of genotype D3 was the most potent inhibitor of MeV infection-induced and IFN-induced ISG expression and generated the highest titer of infectious viral particles. Edmonston triggered the highest levels of MeV infection-induced ISG expression in SiHa cells and produced the lowest titer of infectious particles. Expression of the viral C protein was associated with suppression of MeV infection-induced and type II IFN-induced ISG expression.

Mumps Virus Induces Protein-Kinase-R-Dependent Stress Granules, Partly Suppressing Type III Interferon Production.

Shin Hashimoto, Soh Yamamoto, Noriko Ogasawara, Toyotaka Sato, Keisuke Yamamoto, Hiroshi Katoh, Toru Kubota, Tsukasa Shiraishi, Takashi Kojima, Tetsuo Himi, Hiroyuki Tsutsumi, Shin-Ichi Yokota

PloS one ( PUBLIC LIBRARY SCIENCE ) 11 ( 8 ) e0161793 2016 [Refereed] [International journal]

Authorship： Corresponding author

Stress granules (SGs) are cytoplasmic granular aggregations that are induced by cellular stress, including viral infection. SGs have opposing antiviral and proviral roles, which depend on virus species. The exact function of SGs during viral infection is not fully understood. Here, we showed that mumps virus (MuV) induced SGs depending on activation of protein kinase R (PKR). MuV infection strongly induced interferon (IFN)-λ1, 2 and 3, and IFN-β through activation of IFN regulatory factor 3 (IRF3) via retinoic acid inducible gene-I (RIG-I) and the mitochondrial antiviral signaling (MAVS) pathway. MuV-induced IFNs were strongly upregulated in PKR-knockdown cells. MuV-induced SG formation was suppressed by knockdown of PKR and SG marker proteins, Ras-GTPase-activating protein SH3-domain-binding protein 1 and T-cell-restricted intracellular antigen-1, and significantly increased the levels of MuV-induced IFN-λ1. However, viral titer was not altered by suppression of SG formation. PKR was required for induction of SGs by MuV infection and regulated type III IFN (IFN-λ1) mRNA stability. MuV-induced SGs partly suppressed type III IFN production by MuV; however, the limited suppression was not sufficient to inhibit MuV replication in cell culture. Our results provide insight into the relationship between SGs and IFN production induced by MuV infection.

Intrafamilial, Preferentially Mother-to-Child and Intraspousal, Helicobacter pylori Infection in Japan Determined by Mutilocus Sequence Typing and Random Amplified Polymorphic DNA Fingerprinting.

Shin-ichi Yokota, Mutsuko Konno, Shin-ichi Fujiwara, Nariaki Toita, Michiko Takahashi, Soh Yamamoto, Noriko Ogasawara, Tsukasa Shiraishi

Helicobacter ( WILEY-BLACKWELL ) 20 ( 5 ) 334 - 42 2015.10 [Refereed] [International journal]

BACKGROUND: The infection route of Helicobacter pylori has been recognized to be mainly intrafamilial, preferentially mother-to-child, especially in developed countries. To determine the transmission route, we examined whether multilocus sequence typing (MLST) was useful for analysis of intrafamilial infection. The possibility of intraspousal infection was also evaluated. MATERIALS AND METHODS: Clonal relationships between strains derived from 35 index Japanese pediatric patients, and their family members were analyzed by two genetic typing procedures, MLST and random amplified polymorphic DNA (RAPD) fingerprinting. RESULTS: Mostly coincident results were obtained by MLST and RAPD. By MLST, the allele of loci in the isolates mostly matched between the index child and both the father and mother for 9 (25.7%) of the 35 patients, between the index child and the mother for 25 (60.0%) of the 35 patients. CONCLUSIONS: MLST is useful for analyzing the infection route of H. pylori as a highly reproducible method. Intrafamilial, especially mother-to-children and sibling, infection is the dominant transmission route. Intraspousal infection is also thought to occur in about a quarter in the Japanese families.

Geranylgeranylacetone selectively binds to the HSP70 of Helicobacter pylori and alters its coccoid morphology.

Ewa Grave, Shin-ichi Yokota, Soh Yamamoto, Arisa Tamura, Takako Ohtaki-Mizoguchi, Kenji Yokota, Keiji Oguma, Kazuhiko Fujiwara, Nobuaki Ogawa, Tomoya Okamoto, Michiro Otaka, Hideaki Itoh

Scientific reports ( NATURE PUBLISHING GROUP ) 5 13738 - 13738 2015.09 [Refereed] [International journal]

Geranylgeranylacetone (GGA) is used to treat patients suffering from peptic ulcers and gastritis. We examined the effect of GGA on Helicobacter pylori, which is a causative factor of gastrointestinal diseases. Previously, we have reported that GGA binds specifically to the molecular chaperone HSP70. In this paper, we report that GGA bounds to H. pylori HSP70 (product of the DnaK gene) with 26-times higher affinity than to human HSP70, and induced large conformational changes as observed from surface plasmon resonance and circular dichroism. Binding of GGA suppressed the activity of the H. pylori chaperone. GGA also altered several characteristics of H. pylori cells. GGA-treated cells elicited enhanced interleukin-8 production by gastric cancer cell lines and potentiated susceptibility to complement as compared to untreated cells. GGA also caused morphological alterations in H. pylori as reflected in fewer coccoid-like cells, suggesting that GGA converts H. pylori to an actively dividing, spiral state (vegetative form) from a non-growing, coccoid state. This morphological conversion by GGA resulted in accelerated growth of H. pylori. These results suggest a model in which GGA sensitizes H. pylori to antibiotic treatment by converting the cells to an actively growing state.

Structural characterization of the substrate transfer mechanism in Hsp70/Hsp90 folding machinery mediated by Hop

Sara Alvira, Jorge Cuellar, Alina Roehl, Soh Yamamoto, Hideaki Itoh, Carlos Alfonso, German Rivas, Johannes Buchner, Jose M. Valpuesta

NATURE COMMUNICATIONS ( NATURE PUBLISHING GROUP ) 5 5484 2014.11 [Refereed]

In eukarya, chaperones Hsp70 and Hsp90 act coordinately in the folding and maturation of a range of key proteins with the help of several co-chaperones, especially Hop. Although biochemical data define the Hop-mediated Hsp70-Hsp90 substrate transfer mechanism, the intrinsic flexibility of these proteins and the dynamic nature of their complexes have limited the structural studies of this mechanism. Here we generate several complexes in the Hsp70/Hsp90 folding pathway (Hsp90: Hop, Hsp90: Hop: Hsp70 and Hsp90: Hop: Hsp70 with a fragment of the client protein glucocorticoid receptor (GR-LBD)), and determine their 3D structure using electron microscopy techniques. Our results show that one Hop molecule binds to one side of the Hsp90 dimer in both extended and compact conformations, through Hop domain rearrangement that take place when Hsp70 or Hsp70: GR-LBD bind to Hsp90: Hop. The compact conformation of the Hsp90: Hop: Hsp70: GR-LBD complex shows that GR-LBD binds to the side of the Hsp90 dimer opposite the Hop attachment site.

ATPase Activity and ATP-dependent Conformational Change in the Co-chaperone HSP70/HSP90-organizing Protein ( HOP)*

Soh Yamamoto, Ganesh Prasad Subedi, Shinya Hanashima, Tadashi Satoh, Michiro Otaka, Hideki Wakui, Ken-ichi Sawada, Shin-ichi Yokota, Yoshiki Yamaguchi, Hiroshi Kubota, Hideaki Itoh

JOURNAL OF BIOLOGICAL CHEMISTRY ( AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC ) 289 ( 14 ) 9880 - 9886 2014.04 [Refereed]

Authorship： Lead author

Background: HOP assists protein transfer in the HSP70- and HSP90-dependent protein-folding pathway. Results: HOP hydrolyzed ATP, and the region containing amino acids 1-359 (TPR1-TPR2A) was required for hydrolysis and direct interaction with ATP. Conclusion: HOP has slow ATPase activity and changes its conformation upon ATP hydrolysis. Significance: This is the first demonstration of the ATPase activity of HOP, and may enhance our understanding of the physiological function. Co-chaperones help to maintain cellular homeostasis by modulating the activities of molecular chaperones involved in protein quality control. The HSP70/HSP90-organizing protein (HOP) is a co-chaperone that cooperates with HSP70 and HSP90 in catalysis of protein folding and maturation in the cytosol. We show here that HOP has ATP-binding activity comparable to that of HSP70/HSP90, and that HOP slowly hydrolyzes ATP. Analysis of deletion mutants revealed that the ATPase domain of HOP is in the N-terminal TPR1-DP1-TPR2A segment. In addition, HOP changes its conformation in the presence of ATP. These results indicate that HOP is a unique co-chaperone that undergoes an ATP-dependent conformational change.

The activation mechanism of the aryl hydrocarbon receptor (AhR) by molecular chaperone HSP90

Noriko Tsuji, Kana Fukuda, Yuhtaroh Nagata, Hirotaka Okada, Asami Haga, Shiori Hatakeyama, Shiho Yoshida, Tomoya Okamoto, Miki Hosaka, Kazuhiro Sekine, Kei Ohtaka, Soh Yamamoto, Michiro Otaka, Ewa Grave, Hideaki Itoh

FEBS OPEN BIO ( ELSEVIER SCIENCE LONDON ) 4 796 - 803 2014 [Refereed]

The aryl hydrocarbon receptor is a member of the nuclear receptor superfamily that associates with the molecular chaperone HSP90 in the cytoplasm. The activation mechanism of the AhR is not yet fully understood. It has been proposed that after binding of ligands such as 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD), 3methylcholanthrene (3-MC), or beta-naphthoflavone (beta-NF), the AhR dissociates from HSP90 and translocates to the nucleus. It has also been hypothesized that the AhR translocates to the nucleus and forms a complex with HSP90 and other co-chaperones. There are a few reports about the direct association or dissociation of AhR and HSP90 due to difficulties in purifying AhR. We constructed and purified the PAS domain from AhR. Binding of the AhR-PAS domain to beta-NF affinity resin suggested that it possesses ligand-binding affinity. We demonstrated that the AhR-PAS domain binds to HSP90 and the association is not affected by ligand binding. The ligand 17-DMAG inhibited binding of HSP90 to GST-PAS. In an immunoprecipitation assay, HSP90 was co-immunoprecipitated with AhR both in the presence or absence of ligand. Endogenous AhR decreased in the cytoplasm and increased in the nucleus of HeLa cells 15 min after treatment with ligand. These results suggested that the ligand-bound AhR is translocated to nucleus while in complex with HSP90. We used an in situ proximity ligation assay to confirm whether AhR was translocated to the nucleus alone or together with HSP90. HSP90 was co-localized with AhR after the nuclear translocation. It has been suggested that the ligand-bound AhR was translocated to the nucleus with HSP90. Activated AhR acts as a transcription factor, as shown by the transcription induction of the gene CYP1A1 8 h after treatment with beta-NF. (C) 2014 The Authors. Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.

Aminoglycosides Suppress the Protein Folding Activity of the Molecular Chaperone HSC70: Implication of a Structure-Activity Relationship

Soh Yamamoto, Hideki Wakui, Hiroshi Kubota, Atsushi Kornatsuda, Hideaki Itoh, Shin-Ichi Yokota

CHEMOTHERAPY ( KARGER ) 60 ( 1 ) 37 - 46 2014 [Refereed]

Authorship： Lead author

Background: The mechanism of aminoglycoside (AG)-induced nephrotoxicity has not been fully elucidated. We previously reported that gentamicin suppresses the functions of HSC70, a heat shock cognate protein, which is a cytosolic molecular chaperone in mammalian cells. However, the relationship between HSC70 dysfunction and nephrotoxicity has not been clarified yet. Methods: The effects of 11 AGs, including gentamicin, on the function, protein refolding and substrate binding of HSC70 were examined in vitro. The protein refolding activity of HSC70 was examined by enzymatic activity restoration of the denatured firefly luciferase. Substrate binding activity of HSC70 was examined by the binding of fluorescent-dye-labeled reduced carboxymethlylated alpha-lactalbumin determined by HSC70/substrate complex formation by native polyacrylamide gel electrophoresis. Results: Strong inhibitory activity of AGs on the protein refolding activity of HSC70 was observed for arbekacin, gentamicin, neomycin and sisomicin, but not spectinomycin, streptomycin, ribostamycin and paromomycin, and inhibition was weak for tobramycin, amikacin and kanamycin. Neomycin strongly suppressed the formation of the HSC70/substrate complex and had the lowest concentration that resulted in 50% inhibition (IC50; in the order of 10(-4) nn). Arbekacin, gentamicin, sisomicin and tobramycin had IC50 values in the order of 10(-3) M. Amikacin, ribostamycin and paromomycin had no effective potencies. Conclusions: The inhibition efficacies of AGs for protein refolding of HSC70 were as follows: neomycin >> gentamicin, arbekacin, and sisomicin > tobramycin, amikacin and kanamycin > spectinomycin, streptomycin, ribostamycin and paromomycin. Amino groups and/or hydroxyl groups located at 2', 3',4', and 6' of amino sugar residue II, as well as the number of amino sugar rings were closely associated with the inhibition efficacies of AGs. Inhibition efficacies of AGs towards the function of HSC70 correlated well with the nephrotoxicity of AGs deduced from the in vivo studies previously reported. Amino groups/hydroxyl groups and the number of amino sugar rings of AGs were shown to be important for inhibition efficacies. The results strongly suggest that the AG-induced dysfunction of HSC70 is involved in the nephrotoxicity. (C) 2014 S. Karger AG, Basel

Positive Relationship Between a Polymorphism in Helicobacter pylori Neutrophil-Activating Protein A Gene and Iron-Deficiency Anemia

Shin-ichi Yokota, Nariaki Toita, Soh Yamamoto, Nobuhiro Fujii, Mutsuko Konno

HELICOBACTER ( WILEY-BLACKWELL ) 18 ( 2 ) 112 - 116 2013.04 [Refereed]

Background Numerous studies have suggested a link between iron-deficiency anemia (IDA) and Helicobacter pylori infection. Previously, we found that strains isolated from IDA patients showed higher levels of Fe ion uptake and Fe-ion-dependent rapid proliferation than those of strains derived from patients without IDA. Materials and Methods Twenty-four H.pylori strains from IDA patients (IDA strains) and 25 strains from patients who had H.pylori gastritis without anemia (non-IDA strains) were examined. Their nucleotide sequences of napA, fur, and feoB, which contribute to Fe ion uptake, were determined. Results Numerous polymorphisms of the three genes were found in both strains. Frequency of neutrophil-activating protein A (NapA), which encoded by napA, with threonine at amino acid residue No. 70 (Thr70-type NapA) was significantly higher in IDA strains than in non-IDA strains. Strains with Thr70-type NapA showed significantly higher levels of Fe3+ and Fe2+ uptake than did strains with other types, Ser70-type of NapA, which is found in standard strains. Other significantly different occurrences of polymorphisms between IDA and non-IDA groups were not observed in these genes. Conclusion The results suggest that H.pylori strains with Thr70-type NapA have enhanced Fe ion uptake ability and are associated with the pathogenesis of IDA.

Imiquimod Suppresses Propagation of Herpes Simplex Virus 1 by Upregulation of Cystatin A via the Adenosine Receptor A(1) Pathway

Yuji Kan, Tamaki Okabayashi, Shin-ichi Yokota, Soh Yamamoto, Nobuhiro Fujii, Toshiharu Yamashita

JOURNAL OF VIROLOGY ( AMER SOC MICROBIOLOGY ) 86 ( 19 ) 10338 - 10346 2012.10 [Refereed]

Imiquimod is recognized as an agonist for Toll-like receptor 7 (TLR7) in immunocompetent cells. TLR7, as well as TLR3 and TLR8, triggers the immune responses, such as the production of type I interferons (IFNs) and proinflammatory cytokines via recognition of viral nucleic acids in the infected cells. In this study, we proposed that imiquimod has an IFN-independent antiviral effect in nonimmune cells. Imiquimod, but not resiquimod, suppressed replication of human herpes simplex virus 1 (HSV-1) in FL cells. We analyzed alternation of gene expression by treatment with imiquimod using microarray analysis. Neither type I IFNs, nor TLRs, nor IFN-inducible antiviral genes were induced in imiquimod-treated FL cells. Cystatin A, a host cysteine protease inhibitor, was strongly upregulated by imiquimod and took a major part in the anti-HSV-1 activity deduced by the suppression experiment using its small interfering RNA. Upregulation of cystatin A was suggested to be mediated by antagonizing adenosine receptor A(1) and activating the protein kinase A pathway. Imiquimod, but not resiquimod, was shown to interact with adenosine receptor A(1). Imiquimod-induced anti-HSV-1 activity was observed in other cells, such as HeLa, SiHa, and CaSki cells, in a manner consistent with the cystatin A induction by imiquimod. These results indicated that imiquimod acted as an antagonist for adenosine receptor A(1) and induced a host antiviral protein, cystatin A. The process occurred independently of TLR7 and type I IFNs.

Cytosolic chaperonin CCT possesses GTPase activity

Susumu Noguchi, Kazuyoshi Toyoshima, Soh Yamamoto, Toshio Miyazaki, Michiro Otaka, Sumio Watanabe, Katsunori Imai, Haruki Senoo, Ryoji Kobayashi, Mitsutoshi Jikei, Yasushi Kawata, Hiroshi Kubota, Hideaki Itoh

Am. J. Mol. Biol. 1 ( 3 ) 383 - 390 2012 [Refereed]

Traditional Herbal Medicine, Rikkunshito, Induces HSP60 and Enhances Cytoprotection of Small Intestinal Mucosal Cells as a Nontoxic Chaperone Inducer

Kumiko Tamaki, Michiro Otaka, Tomoyoshi Shibuya, Naoto Sakamoto, Soh Yamamoto, Masaru Odashima, Hideaki Itoh, Sumio Watanabe

EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE ( HINDAWI PUBLISHING CORPORATION ) 2012 1 - 7 2012 [Refereed]

Increasing incidence of small intestinal ulcers associated with nonsteroidal anti-inflammatory drugs (NSAIDs) has become a topic with recent advances of endoscopic technology. However, the pathogenesis and therapy are not fully understood. The aim of this study is to examine the effect of Rikkunshito (TJ-43), a traditional herbal medicine, on expression of HSP60 and cytoprotective ability in small intestinal cell line (IEC-6). Effect of TJ-43 on HSP60 expression in IEC-6 cells was evaluated by immunoblot analysis. The effect of TJ-43 on cytoprotective abilities of IEC-6 cells against hydrogen peroxide or indomethacin was studied by MTT assay, LDH-release assay, caspase-8 activity, and TUNEL. HSP60 was significantly induced by TJ-43. Cell necrosis and apoptosis were significantly suppressed in IEC-6 cells pretreated by TJ-43 with overexpression of HSP60. Our results suggested that HSP60 induced by TJ-43 might play an important role in protecting small intestinal epithelial cells from apoptosis and necrosis in vitro.

Evidence for Enhanced Cytoprotective Function of HSP90-Overexpressing Small Intestinal Epithelial Cells

Kumiko Tamaki, Michiro Otaka, Makiko Takada, Soh Yamamoto, Masaru Odashima, Hideaki Itoh, Sumio Watanabe

DIGESTIVE DISEASES AND SCIENCES ( SPRINGER ) 56 ( 7 ) 1954 - 1961 2011.07 [Refereed]

In the clinical field, increasing incidence of small intestinal ulcers associated with nonsteroidal anti-inflammatory drugs (NSAIDs) has become a topic with the advances of capsule endoscopy and balloon enteroscopy technology for the detection of small intestinal lesions. However, the pathogenesis of NSAID-induced mucosal damage, defensive mechanism of intestinal epithelial cells, and therapy for small intestinal mucosal lesion have not been fully understood. Heat shock proteins (HSPs) are involved in cytoprotection mediated by their function as a molecular chaperone. Since the function of HSP90 in the intestinal epithelial cells has not been well investigated, we examined the cytoprotective ability of HSP90-overexpressing small intestinal epithelial cells against hydrogen peroxide-induced or indomethacin-induced cell damage. cDNA of human HSP90 gene was transfected to rat small intestinal epithelial cells (IEC-6 cells), and HSP90-overexpressing cells (IEC-6-90 cells) were selected and cloned. Anti-necrotic abilities and anti-apoptotic abilities of IEC-6-90 cells were compared with IEC-6-mock cells (transfected with vector alone). To examine the specific contribution of HSP90 on cytoprotection of IEC-6-90 cells, cytoprotective ability of IEC-6-90 cells was analyzed with or without pretreatment with functional inhibitor of HSP90, geldanamycine analog, followed by hydrogen peroxide-challenge or indomethacin-challenge. Hydrogen peroxide-induced or indomethacin-induced cell necrosis and apoptosis were significantly suppressed in IEC-6-90 cells. The cytoprotective ability of IEC-6-90 cells was suppressed by HSP90 inhibitor. Our results suggest that HSP90 might play an important role in protecting small intestinal epithelial cells from hydrogen peroxide-induced or indomethacin-induced cell injury in vitro, and raised the possibility of protection of small intestinal epithelial cells by manipulation of HSP90 expression.

Increased expression of co-chaperone HOP with HSP90 and HSC70 and complex formation in human colonic carcinoma

Hiroshi Kubota, Soh Yamamoto, Eri Itoh, Yuki Abe, Asami Nakamura, Yukina Izumi, Hirotaka Okada, Masatake Iida, Hiroshi Nanjo, Hideaki Itoh, Yuzo Yamamoto

CELL STRESS & CHAPERONES ( SPRINGER ) 15 ( 6 ) 1003 - 1011 2010.11 [Refereed]

Co-chaperone HOP (also called stress-inducible protein 1) is a co-chaperone that interacts with the cytosolic 70-kDa heat shock protein (HSP70) and 90-kDa heat shock protein (HSP90) families using different tetratricopeptide repeat domains. HOP plays crucial roles in the productive folding of substrate proteins by controlling the chaperone activities of HSP70 and HSP90. Here, we examined the levels of HOP, HSC70 (cognate of HSP70, also called HSP73), and HSP90 in the tumor tissues from colon cancer patients, in comparison with the non-tumor tissues from the same patients. Expression level of HOP was significantly increased in the tumor tissues (68% of patients, n = 19). Levels of HSC70 and HSP90 were also increased in the tumor tissues (95% and 74% of patients, respectively), and the HOP level was highly correlated with those of HSP90 (r = 0.77, p < 0.001) and HSC70 (r = 0.68, p < 0.01). Immunoprecipitation experiments indicated that HOP complexes with HSC70 or HSP90 in the tumor tissues. These data are consistent with increased formation of co-chaperone complexes in colon tumor specimens compared to adjacent normal tissue and could reflect a role for HOP in this process.

Overexpression of a 60-kDa heat shock protein enhances cytoprotective function of small intestinal epithelial cells

Makiko Takada, Michiro Otaka, Taiji Takahashi, Yuko Izumi, Kumiko Tamaki, Tomoyoshi Shibuya, Naoto Sakamoto, Taro Osada, Sou Yamamoto, Ryuichi Ishida, Masaru Odashima, Hideaki Itoh, Sumio Watanabe

LIFE SCIENCES ( PERGAMON-ELSEVIER SCIENCE LTD ) 86 ( 13-14 ) 499 - 504 2010.03 [Refereed]

Aims With the advancement of small intestinal (double balloon and capsule) endoscopy technology, incidence of small intestinal lesion caused by nonsteroidal anti-inflammatory drugs (NSAIDs) has been known to be high However, therapy for small intestinal mucosal lesion has not yet been developed Previous studies have shown that heat shock proteins (HSPs) are involved in cytoprotection mediated by their function as a molecular chaperone In this study, we examined the effect of HSP60 or HSP70 overexpression on hydrogen peroxide-induced (H(2)O(2)) or indomethacin-induced cell damage in the small intestinal epithelial cells Main methods cDNA of human HSP60 or HSP70 was transfected to rat small intestinal (IEC-6) cells, and HSP60- or HSP70-overexpressing cells were cloned IEC-6 cells transfected with vector only were used as control cells These cells were treated with H(2)O(2) (0-0 14 mM) or indomethacin (0-25 mM) The cell viability was determined by MIT-assay. Cell necrosis was evaluated by LDH-release assay Furthei, apoptosis was evaluated by caspases-3/7 activity and TUNEL assay Key findings Cell viability after H(2)O(2) or indomethacin treatment was significantly higher in HSP60-overexpiessing cells compared with that in control cells and HSP60-overexpressing cells Apoptotic cells were also reduced in HSP60-overexpressing Conclusion These results indicate that HSP60 plays an important role in protecting small intestinal mucosal cells from H(2)O(2)-induced or indomethacin-induced cell injury HSP70-overexpressing cells did not show anti-apoptotic ability Significance These findings possibly suggest that function of each HSP is different in the small intestine Therefore, for the therapy of small intestinal mucosal lesion. HSP60-induction therapy could be a new therapeutic strategy (C) 2010 Elsevier Inc All rights reserved.

Gentamicin inhibits HSP70-assisted protein folding by interfering with substrate recognition

Soh Yamamoto, Shunsuke Nakano, Kensuke Owari, Kazuhiko Fuziwara, Nobuaki Ogawa, Michiro Otaka, Kumiko Tamaki, Sumio Watanabe, Atsushi Komatsuda, Hideki Wakui, Ken-ichi Sawada, Hiroshi Kubota, Hideaki Itoh

FEBS LETTERS ( ELSEVIER SCIENCE BV ) 584 ( 4 ) 645 - 651 2010.02 [Refereed]

Authorship： Lead author

We previously reported that gentamicin (GM) specifically binds to heat-shock protein with subunit molecular masses of 70 kDa (HSP70). In the present study, we have investigated the effects of GM binding on HSP70-assisted protein folding in vitro. The C-terminal, and not the N-terminal of HSP70 was found to bind to GM. GM significantly suppressed refolding of firefly luciferase in the presence of HSP70 and HSP40, although the ATPase activity of HSP70 was unaffected by GM. A surface plasmon resonance analysis revealed that GM specifically interferes with the binding of HSP70 to a model peptide that mimics the exposed hydrophobic surface of the folding intermediates. These results indicated that GM inhibits the chaperone activity of HSP70 and may suppress protein folding via inhibition of HSP70 in vivo.

Angiotensin Receptor Blocker Directly Binds to HSP and Stimulates its Production in the Brain

Taku Sugawara, Kohei Kokubun, Ryuichi Ishida, Kazuhiko Fujiwara, Sou Yamamoto, Hiroyuki Kinouchi, Hideaki Itoh, Kazuo Mizoi

RECENT ADVANCES IN MATHEMATICS AND COMPUTERS IN BUSINESS, ECONOMICS, BIOLOGY & CHEMISTRY ( WORLD SCIENTIFIC AND ENGINEERING ACAD AND SOC ) 350 - + 2010 [Refereed]

Antihypertensive angiotensin II type 1 receptor blockers (ARBs) have neuroprotective effects that were independent of the reduction of blood pressure. We have previously shown that vulnerable hippocampal CA1 neurons underwent delayed cell death through mitochondria-dependent apoptotic pathway after global cerebral ischemia, but ARB protected these neurons from cell death. To elucidate the mechanism of neuroprotection by ARB candesartan, candesartan-specific binding proteins were first investigated using candesartan-affinity column and rat hippocampal tissue. And, the affinity of ARB and the binding protein was further examined by BIAcore binding assay. Then, the distribution and expression of the protein were characterized by immunohisotochemistry and Western blots. By affinity column study, molecular chaperone heat shock protein 90 (HSP90) was identified as a binding target of candesartan. BIAcore assay proved functional binding of candesartan to HSP90. Immunohistochemistry showed increased HSP90 expression in the hippocampal CA1 neurons as early as 1 day after candesartan treatment. Westen blots confirmed temporal changes in HSP90 expression.HSP90 maintains the stability of the proteins as a molecular chaperone and has been recently proven to inhibit apoptosis in in vitro studies. Our data suggest that HSP90 may play an important role in neuronal protection by ARB treatment through blocking mitochondria-dependent apoptosis.

Cisplatin differently affects amino terminal and carboxyl terminal domains of HSP90

Ryuichi Ishida, Yuka Takaoka, Soh Yamamoto, Toshio Miyazaki, Michiro Otaka, Sumio Watanabe, Atushi Komatsuda, Hideki Wakui, Ken-ichi Sawada, Hiroshi Kubota, Hideaki Itoh

FEBS LETTERS ( ELSEVIER SCIENCE BV ) 582 ( 28 ) 3879 - 3883 2008.11 [Refereed]

The 90-kDa heat shock protein (HSP90) is a molecular chaperone that assists in the folding and assembly of proteins in the cytosol. We previously demonstrated that the antineoplastic reagent, cisplatin, inhibits the aggregation prevention activity of mammalian HSP90. We now show that cisplatin binds both the amino terminal and carboxyl terminal domains of the human HSP90 and differently affects these two domains. Cisplatin blocks the aggregation prevention activity of HSP90C, but not HSP90N. In contrast, cisplatin induces a conformational change in HSP90N, but not HSP90C. These results indicate that cisplatin modulates the HSP90 activities through two different mechanisms using the two distinct binding sites of the HSP90 molecule. (C) 2008 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

The induction mechanism of the molecular chaperone HSP70 in the gastric mucosa by Geranylgeranylacetone (HSP-inducer)

Michiro Otaka, Soh Yamamoto, Kaori Ogasawara, Yuka Takaoka, Susumu Noguchi, Toshio Miyazaki, Akira Nakai, Masaru Odashima, Tamotsu Matsuhashi, Sumio Watanabe, Hideaki Itoh

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS ( ACADEMIC PRESS INC ELSEVIER SCIENCE ) 353 ( 2 ) 399 - 404 2007.02 [Refereed]

To elucidate the induction mechanism of HSP70 by geranylgeranylacetone (GGA), we investigated GGA specific binding proteins using a GGA-affinity column. Alteration of chaperone activity of HSP70 and binding affinity of HSP70 to heat shock factor-1 (HSF1) was evaluated in the presence or absence of GGA. The binding domain of HSP70 to GGA was also analyzed. A 70-kDa protein eluted by 10 mM GGA from the GGA-affinity column was identical to constitutively expressed HSP70 on immunoblotting. GGA-binding domain of HSP70 was C-terminal of the protein as peptide-binding domain (HSP70C). The chaperone activity of HSP70 and recombinant HSP70C was suppressed by GGA. Furthermore, dissociation of the HSP70 from HSF-I was observed in the presence of GGA. GGA preferentially binds to the C-terminal of HSP70 which binds to HSF-1. After dissociation of HSP70, free HSF-1 could acquire the ability to bind to HSE (the promoter region of HSP70) gene. (c) 2006 Elsevier Inc. All rights reserved.

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