National Institute of Infectious Disease

Tokyo, Japan

National Institute of Infectious Disease

Tokyo, Japan
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Elwell C.A.,University of California at San Francisco | Jiang S.,University of California at San Francisco | Kim J.H.,University of California at San Francisco | Lee A.,University of California at San Francisco | And 4 more authors.
PLoS Pathogens | Year: 2011

The obligate intracellular pathogen Chlamydia trachomatis replicates within a membrane-bound inclusion that acquires host sphingomyelin (SM), a process that is essential for replication as well as inclusion biogenesis. Previous studies demonstrate that SM is acquired by a Brefeldin A (BFA)-sensitive vesicular trafficking pathway, although paradoxically, this pathway is dispensable for bacterial replication. This finding suggests that other lipid transport mechanisms are involved in the acquisition of host SM. In this work, we interrogated the role of specific components of BFA-sensitive and BFA-insensitive lipid trafficking pathways to define their contribution in SM acquisition during infection. We found that C. trachomatis hijacks components of both vesicular and non-vesicular lipid trafficking pathways for SM acquisition but that the SM obtained from these separate pathways is being utilized by the pathogen in different ways. We show that C. trachomatis selectively co-opts only one of the three known BFA targets, GBF1, a regulator of Arf1-dependent vesicular trafficking within the early secretory pathway for vesicle-mediated SM acquisition. The Arf1/GBF1-dependent pathway of SM acquisition is essential for inclusion membrane growth and stability but is not required for bacterial replication. In contrast, we show that C. trachomatis co-opts CERT, a lipid transfer protein that is a key component in non-vesicular ER to trans-Golgi trafficking of ceramide (the precursor for SM), for C. trachomatis replication. We demonstrate that C. trachomatis recruits CERT, its ER binding partner, VAP-A, and SM synthases, SMS1 and SMS2, to the inclusion and propose that these proteins establish an on-site SM biosynthetic factory at or near the inclusion. We hypothesize that SM acquired by CERT-dependent transport of ceramide and subsequent conversion to SM is necessary for C. trachomatis replication whereas SM acquired by the GBF1-dependent pathway is essential for inclusion growth and stability. Our results reveal a novel mechanism by which an intracellular pathogen redirects SM biosynthesis to its replicative niche. © 2011 Elwell et al.

Braconi C.,Ohio State University | Valeri N.,Ohio State University | Gasparini P.,Ohio State University | Huang N.,Ohio State University | And 5 more authors.
Clinical Cancer Research | Year: 2010

Purpose: Hepatocellular cancer (HCC) is highly resistant to chemotherapy and is associated with poor prognosis. Chronic hepatitis C virus (HCV) infection is a major cause of HCC. However, the effect of viral proteins in mediating chemosensitivity in tumor cells is unknown. We postulated that HCV viral proteins could modulate therapeutic responses by altering host cell microRNA (miRNA) expression. Experimental Design: HepG2 malignant hepatocytes were stably transfected with full-length HCV genome (Hep-394) or an empty vector (Hep-SWX). MiRNA profiling was done by using a custom microarray, and the expression of selected miRNAs was validated by real-time PCR. Protein expression was assessed by Western blotting, whereas caspase activation was assessed by a luminometric assay. Results: The IC50 to sorafenib was lower in Hep-394 compared with Hep-SWX control cells. Alterations in miRNA expression occurred with 10 miRNAs downregulated >2-fold and 23 miRNAs upregulated >2-fold in Hep-394 cells compared with controls. Of these, miR-193b was overexpressed by 5-fold in Hep-394 cells. miR-193b was predicted to target Mcl-1, an antiapoptotic protein that can modulate the response to sorafenib. The expression of Mcl-1 was decreased, and basal caspase-3/7 activity and poly ADP ribose polymerase cleavage were increased in Hep-394 cells compared with controls. Moreover, transfection with precursors to miR-193b decreased both Mcl-1 expression and the IC50 to sorafenib. Conclusions: Cellular expression of full-length HCV increases sensitivity to sorafenib by the miRNA-dependent modulation of Mcl-1 and apoptosis. Modulation of miRNA responses may be a useful strategy to enhance response to chemotherapy in HCC. ©2010 AACR.

Taira K.,Azabu University | Saitoh Y.,Azabu University | Okada N.,Azabu University | Sugiyama H.,National Institute of Infectious Disease | Kapel C.M.O.,Copenhagen University
Veterinary Parasitology | Year: 2012

Infectivity of Toxocara cati larvae in muscle tissue of chickens after storage at 4. °C and -25. °C was assessed in a mouse bioassay to provide information on the risk of meat-borne toxocarosis. Muscle tissue samples of 30-day old T. cati infections were stored at 4. °C for 14 and 28 days and at -25. °C for 12, 24 and 48. h, whereafter, larvae were released by digestion. For each experimental group, the released larvae were inoculated in six mice. After 15 days, mice were euthanized and larval burden was assessed by digestion. In the control group (no storage of the infected chicken meat), 47.9% of the inoculated larvae established in mice, whereas storage of meat at 4. °C for 14 days or 28 days reduced the recovery to 24.1% or 3.3%, respectively. Muscle larvae exposed to -25. °C for 12, 24 or 48. h did not establish in the mice. The observation that larvae retain infective after refrigeration at exposure in 4. °C for 28 days, emphasize the zoonotic potential of poultry meat as a causative agent of human toxocarosis. © 2012 Elsevier B.V.

Hori J.,Nippon Medical School | Taniguchi H.,Nippon Medical School | Wang M.,Nippon Medical School | Oshima M.,National Institute of Infectious Disease | Azuma M.,Tokyo Medical and Dental University
Investigative Ophthalmology and Visual Science | Year: 2010

PURPOSE. The pathway between the glucocorticoid-induced tumor necrosis factor receptor family-related protein (GITR) and GITR ligand (GITRL) has been shown to control the function of regulatory T cells (Treg). The present study was conducted to investigate the role of this pathway and Treg in establishing immune privilege status for corneal allografts. METHODS. Corneas of C57BL/6 mice were orthotopically transplanted into the eyes of BALB/c mice, and graft survival was assessed. A separate set of BALB/c mice received an anterior chamber injection of C57BL/6 splenocytes, and induction of allo-specific anterior chamber-associated immune deviation was assessed. Recipients were intraperitoneally administrated anti-GITRL, anti-CD25 monoclonal antibodies (mAb), or control immunoglobulin (IgG). Expressions of GITRL, GITR, and Foxp3 in the allografts were assessed. In vitro, cornea pretreated with anti-GITRL mAb or control IgG was incubated with T cells, and destruction of corneal endothelial cells and the population of Foxp3 +CD25 +CD4 + T cells were assessed. RESULTS. GITRL was expressed constitutively in the cornea and iris-ciliary body. GITRL-expressing allografts were infiltrated with Foxp3+GITR+CD25+CD4 + T cells. Blockade of GITRL did not affect allo-specific ACAID but led to infiltration of Foxp3(-)CD4 + T cells and allograft rejection. Depletion of CD25+CD4 + Treg also accelerated allograft rejection. Destruction of corneal endothelial cells by T cells was significantly enhanced in GITRL-blocked cornea compared with control cornea. Foxp3+CD25+CD4 + T cells were increased after incubation with GITRL-expressing cornea, but not with GITRL blocked cornea. CONCLUSIONS. Presence of Foxp3+CD25+CD4 + Treg in the allograft is necessary for allograft survival. GITRL-dependent expansion of Treg within the cornea is one mechanism underlying immune privilege in corneal allografts. © Association for Research in Vision and Ophthalmology.

Harada K.,Fukuoka University | Fujimoto T.,National Institute of Infectious Disease | Asato Y.,Asato Eye Clinic | Uchio E.,Fukuoka University
Clinical Ophthalmology | Year: 2015

Background: Acute hemorrhagic conjunctivitis (AHC) is a highly contagious enterovirus infection of the conjunctiva and cornea. Coxsackievirus A24 variant (CA24v) is one of its etiological agents. We report a clinical, epidemiological, and virological analysis of a large epidemic of AHC that occurred from May to September, 2011, in Okinawa, Japan. Methods: Clinical and epidemic aspects were evaluated for 435 AHC patients (348 bilateral and 87 unilateral, 783 eyes). Virological studies were carried out on nine isolates from ten patients. Virus isolation and direct detection of the enterovirus genome by the reverse transcription polymerase chain reaction method and complete nucleotide sequencing of the VP1 gene and phylogeny-based classification using the VP4 sequences were carried out. Results: The 11–15-year age group comprised the highest (62.0%) proportion of cases among all age groups. Conjunctival hyperemia was present in all patients, and subconjunctival hemorrhage, superficial punctate keratitis, and preauricular lymphadenopathy were present in 25.4%, 10.3%, and 7.8% of eyes, respectively. CA24v was isolated from the epidemic strain, and phylogenetic analysis based on a fragment of the VP1 gene showed 96%–97% identity between the current strain and the recent China/GD01/2010 strain. Conclusion: These findings demonstrate that the clinical and epidemiological features of AHC observed in this study were similar to those of the past epidemic in the same region. It should be noted that sequential outbreaks of AHC due to CA24v might occur in the same location after a considerable period of time, and public health precautions are necessary to control this explosive epidemic. © 2015 Harada et al.

Nakayama T.,Osaka University | Oishi K.,National institute of infectious disease
FEMS Microbiology Letters | Year: 2013

Although studies have reported numerous effects of coffee on human health, few studies have examined its specific effects on gut microbiota. This study aimed to clarify the influence of coffee and galacto-oligosaccharide (GOS) consumption on gut microbiota and host responses. After mice consumed coffee and GOS, their intestines were sampled, and the bacterial counts were measured with quantitative RT-PCR. Results showed that GOS consumption significantly increased total bacteria counts in the proximal colon. Although Escherichia coli and Clostridium spp. counts significantly decreased in the proximal colon, Bifidobacterium spp. counts increased remarkably in the same area. A bacterial growth inhibition assay was also conducted, and the results showed that E. coli growth was inhibited only by a coffee agar. Host responses were also investigated, revealing that coffee and GOS consumption remarkably increased aquaporin8 expression in the proximal colon. In conclusion, coffee has antibiotic effects, and GOS significantly decreased E. coli and Clostridium spp. counts, but increased Bifidobacterium spp. counts remarkably. Aquaporin8 expression was also increased with a mixture of coffee and GOS consumption. This is the first study to demonstrate that coffee consumption can regulate gut microbiota and increase aquaporin8, both of which are necessary for maintaining intestinal balance. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd.

Kishishita N.,University of Tokyo | Matsuno T.,University of Tokyo | Takahashi Y.,National Institute of Infectious Disease | Takaba H.,University of Tokyo | And 2 more authors.
EMBO Reports | Year: 2010

Variable lymphocyte receptors (VLRs) are antigen receptors in the jawless vertebrates lamprey and hagfish. VLR genes are classified into VLRA and VLRB, and lymphocytes expressing VLRA are T-cell-like, whereas those expressing VLRB are B-cell-like in the sea lamprey. Diverse VLR genes are assembled somatically in lymphocytes; however, how the assembly is regulated is still largely unknown. Here, we analyse VLR gene assembly at the single-cell level in the inshore hagfish (Eptatretus burgeri). Each lymphocyte assembles and transcribes only one type of VLR gene, either VLRA or VLRB. In general, monoallelic assembly of VLR was observed, but diallelic assembly was found in some casesin many of which, one allele was functional and the other was defective. In fact, all VLR-assembled lymphocytes contained at least one functional VLR gene. Together, these results indicate a feedback inhibition of VLR assembly and selection of VLR-positive lymphocytes. © 2010 EUROPEAN MOLECULAR BIOLOGY ORGANIZATION.

Okabe N.,National Institute of Infectious Disease
Japan Medical Association Journal | Year: 2011

The epidemic of novel influenza in Japan began with the detection of the first patient in May 2009, spread to various parts of the country in mid-June, looked like the winter of an ordinary season in October and November, and finally turned to a decrease in early December. Cases with severe pneumonia and acute encephalopathy were reported, as well as deaths. However, the situations in Japan in terms of disease expansion after the first case, the trends of hospitalized patients, and the occurrence of deaths were considerably different from those in other countries. This article briefly describes the epidemiologic situation in Japan focusing on the difference from that in other countries.

Taguchi F.,Nippon Veterinary and Life Science University | Hirai-Yuki A.,National Institute of Infectious Disease
Frontiers in Microbiology | Year: 2012

In this review, we report that the receptor of mouse hepatitis virus (MHV), carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), is an important determinant of mouse susceptibility to MHV infection. This finding was revealed by using mouse strains with two different allelic forms of the MHV receptor, Ceacam1a and Ceacam1b. Although previous studies indicated that susceptibility is determined by a single gene, Ceacam 1, our recent work in gene-replaced mice with chimeric Ceacam1 pointed toward the involvement of other host factors (genes) in the susceptibility. Studies on mouse susceptibility to MHV, as well as the factors involved in their susceptibility, are overviewed. © 2012 Taguchi and Hirai-Yuki.

The Regents Of The University Of California, Japan National Institute of Biomedical Innovation and National Institute Of Infectious Disease | Date: 2011-08-29

This invention provides a peptide/nucleic acid composition for oral/mucosal, dual-modal activation of immune protection systems.

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