Publications by authors named "Yuichi Hirata"

31 Publications

Assessment of the confidence interval in the multivariable normal tissue complication probability model for predicting radiation-induced liver disease in primary liver cancer.

J Radiat Res 2021 May;62(3):483-493

Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan.

We developed a confidence interval-(CI) assessing model in multivariable normal tissue complication probability (NTCP) modeling for predicting radiation-induced liver disease (RILD) in primary liver cancer patients using clinical and dosimetric data. Both the mean NTCP and difference in the mean NTCP (ΔNTCP) between two treatment plans of different radiotherapy modalities were further evaluated and their CIs were assessed. Clinical data were retrospectively reviewed in 322 patients with hepatocellular carcinoma (n = 215) and intrahepatic cholangiocarcinoma (n = 107) treated with photon therapy. Dose-volume histograms of normal liver were reduced to mean liver dose (MLD) based on the fraction size-adjusted equivalent uniform dose. The most predictive variables were used to build the model based on multivariable logistic regression analysis with bootstrapping. Internal validation was performed using the cross-validation leave-one-out method. Both the mean NTCP and the mean ΔNTCP with 95% CIs were calculated from computationally generated multivariate random sets of NTCP model parameters using variance-covariance matrix information. RILD occurred in 108/322 patients (33.5%). The NTCP model with three clinical and one dosimetric parameter (tumor type, Child-Pugh class, hepatitis infection status and MLD) was most predictive, with an area under the receiver operative characteristics curve (AUC) of 0.79 (95% CI 0.74-0.84). In eight clinical subgroups based on the three clinical parameters, both the mean NTCP and the mean ΔNTCP with 95% CIs were able to be estimated computationally. The multivariable NTCP model with the assessment of 95% CIs has potential to improve the reliability of the NTCP model-based approach to select the appropriate radiotherapy modality for each patient.
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http://dx.doi.org/10.1093/jrr/rrab011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8127660PMC
May 2021

Paradoxical Regulation of Allogeneic Bone Marrow Engraftment and Immune Privilege by Mesenchymal Cells and Adenosine.

Transplant Cell Ther 2021 01 19;27(1):92.e1-92.e5. Epub 2020 Sep 19.

Columbia Center for Translational Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA; Columbia Stem Cell Initiative, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA; Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA; Center for Inflammation Research, Department of Anesthesia, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA; Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA. Electronic address:

Although mesenchymal stromal cell (MSC) transfer has long drawn attention owing to its immunosuppressive potential to treat immune-mediated diseases, the role of endogenous MSCs in immune regulation in vivo has remained largely unclear. MSCs constitute the hematopoietic stem cell (HSC) niche, perhaps contributing to immune protection of HSCs, termed immune privilege. Our recent study demonstrates that immune privilege of HSCs is endowed by niche-residential regulatory T cells (Tregs), which promote allogeneic HSC engraftment. This immune privilege depends on cell surface ectoenzymes CD39 and CD73 on niche Tregs, which generate extracellular adenosine, a nucleotide known to suppress immunity and potentiate Tregs. Another niche constituent, leptin receptor-expressing (lepr) perivascular MSCs, also highly express CD39 and CD73, prompting us to study their roles in immune privilege. This work demonstrates an unexpected negative regulation of immune privilege by MSC-derived adenosine. CD39 deletion in lepr cells increased and potentiated effector memory-like niche Tregs, promoting allogeneic HSC engraftment. CD39 deletion in Tregs also activated niche Tregs, while abrogating engraftment. These observations demonstrate paradoxical effects of MSC-derived adenosine to activate immunity, revealing a previously undescribed dual roles of adenosine. Adenosine from both Tregs and MSCs inhibits niche Tregs, whereas adenosine from Tregs, but not that from MSCs, acts as an effector molecule of immune privilege.
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http://dx.doi.org/10.1016/j.bbmt.2020.09.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8284723PMC
January 2021

Transfer of stem cell niche-residential regulatory T cells prevents post-irradiation bone marrow injury.

Haematologica 2021 03 1;106(3):891-893. Epub 2021 Mar 1.

Columbia Center for Translational Immunology, Columbia University College of Physicians and Surgeons, New York, NY

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http://dx.doi.org/10.3324/haematol.2019.221820DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7928002PMC
March 2021

Generation of functional lungs via conditional blastocyst complementation using pluripotent stem cells.

Nat Med 2019 11 7;25(11):1691-1698. Epub 2019 Nov 7.

Columbia Center for Human Development and Division of Pulmonary, Allergy, Critical Care, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA.

Millions of people worldwide with incurable end-stage lung disease die because of inadequate treatment options and limited availability of donor organs for lung transplantation. Current bioengineering strategies to regenerate the lung have not been able to replicate its extraordinary cellular diversity and complex three-dimensional arrangement, which are indispensable for life-sustaining gas exchange. Here we report the successful generation of functional lungs in mice through a conditional blastocyst complementation (CBC) approach that vacates a specific niche in chimeric hosts and allows for initiation of organogenesis by donor mouse pluripotent stem cells (PSCs). We show that wild-type donor PSCs rescued lung formation in genetically defective recipient mouse embryos unable to specify (due to Ctnnb1 mutation) or expand (due to Fgfr2 mutation) early respiratory endodermal progenitors. Rescued neonates survived into adulthood and had lungs functionally indistinguishable from those of wild-type littermates. Efficient chimera formation and lung complementation required newly developed culture conditions that maintained the developmental potential of the donor PSCs and were associated with global DNA hypomethylation and increased H4 histone acetylation. These results pave the way for the development of new strategies for generating lungs in large animals to enable modeling of human lung disease as well as cell-based therapeutic interventions.
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http://dx.doi.org/10.1038/s41591-019-0635-8DOI Listing
November 2019

CD150 CD4 T cells and CD150 regulatory T cells regulate hematopoietic stem cell quiescence via CD73.

Haematologica 2019 06 13;104(6):1136-1142. Epub 2018 Dec 13.

Columbia Center for Translational Immunology, Columbia University College of Physicians and Surgeons, New York, NY, USA

Various extrinsic signals tightly control hematopoietic stem cell quiescence. Our recent study showed that hematopoietic stem cells are regulated by a special FoxP3 regulatory T-cell population with high expression of a hematopoietic stem cell marker, CD150. Extracellular adenosine generated via a cell-surface ectoenzyme CD39 on CD150 regulatory T cells maintained hematopoietic stem cell quiescence. It remains unclear how conventional T cells and the other cell-surface ectoenzyme, CD73, contribute to regulation of hematopoietic stem cells. This work shows that CD150 regulatory T cells as well as unique CD150 CD4 conventional T cells regulate hematopoietic stem cells via CD73. Global CD73 deletion increased the numbers of hematopoietic stem cells, cycling stem cell frequencies, and levels of reactive oxygen species in hematopoietic stem cells. antioxidant treatment inhibited the increase of hematopoietic stem cells in CD73 knockout mice, suggesting that CD73 maintains stem cell quiescence by preventing oxidative stress. High levels of CD73 expression were frequently found on CD150 regulatory T cells and CD150 FoxP3CD4 T cells within the bone marrow. Transfer of these CD150 regulatory T cells and CD150 CD4 conventional T cells abolished the increase of hematopoietic stem cells in CD73 knockout mice. In addition, the increase of stem cells in CD73 knockout mice was also inhibited by pharmacological activation of adenosine receptor 2A which is highly expressed by hematopoietic stem cells. Taken together, these results suggest that CD73 of CD150 regulatory T cells and CD150 CD4 conventional T cells protects hematopoietic stem cells from oxidative stress, maintaining stem cell quiescence via adenosine receptor 2A.
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http://dx.doi.org/10.3324/haematol.2018.198283DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6545860PMC
June 2019

Metabolome analysis for pancreatic cancer risk in nested case-control study: Japan Public Health Center-based prospective Study.

Cancer Sci 2018 May 16;109(5):1672-1681. Epub 2018 Apr 16.

Epidemiology and Prevention Group, Center for Public Health Sciences, National Cancer Center, Tokyo, Japan.

Discovery of a high-risk group for pancreatic cancer is important for prevention of pancreatic cancer. The present study was conducted as a nested case-control study including 170 pancreatic cancer cases and 340 matched controls of our population-based cohort study involving 30 239 subjects who answered a baseline questionnaire and supplied blood samples. Twelve targeted metabolites were quantitatively analyzed by gas chromatography/tandem mass spectrometry. Odds ratios (OR) and their corresponding 95% confidence intervals (CI) were calculated using conditional logistic regression models. Statistically significant P-value was defined as P < .05. Increasing 1,5-anhydro-d-glucitol (1,5-AG) levels were associated with a decreasing trend in pancreatic cancer risk (OR of quartile 4 [Q4], 0.50; 95% CI, 0.27-0.93; P = .02). Increasing methionine levels were also associated with an increasing trend of pancreatic cancer risk (OR of Q4, 1.79; 95% CI, 0.94-3.40: P = .03). Additional adjustment for potential confounders attenuated the observed associations of 1,5-AG and methionine (P for trend = .06 and .07, respectively). Comparing subjects diagnosed in the first 0-6 years, higher levels of 1,5-AG, asparagine, tyrosine and uric acid showed a decreasing trend for pancreatic cancer risk (P for trend = .04, .04, .04 and .02, respectively), even after adjustment for potential confounders. We found that the 12 target metabolites were not associated with pancreatic cancer risk. However, metabolic changes in the subjects diagnosed in the first 0-6 years showed a similar tendency to our previous reports. These results might suggest that these metabolites are useful for early detection but not for prediction of pancreatic cancer.
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http://dx.doi.org/10.1111/cas.13573DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5980145PMC
May 2018

CD150 Bone Marrow Tregs Maintain Hematopoietic Stem Cell Quiescence and Immune Privilege via Adenosine.

Cell Stem Cell 2018 03 15;22(3):445-453.e5. Epub 2018 Feb 15.

Columbia Center for Translational Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA; Columbia Stem Cell Initiative, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA; Department of Pediatrics, Division of Hematology and Oncology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA. Electronic address:

A crucial player in immune regulation, FoxP3 regulatory T cells (Tregs) are drawing attention for their heterogeneity and noncanonical functions. Here, we describe a Treg subpopulation that controls hematopoietic stem cell (HSC) quiescence and engraftment. These Tregs highly expressed an HSC marker, CD150, and localized within the HSC niche in the bone marrow (BM). Specific reduction of BM Tregs achieved by conditional deletion of CXCR4 in Tregs increased HSC numbers in the BM. Adenosine generated via the CD39 cell surface ectoenzyme on niche Tregs protected HSCs from oxidative stress and maintained HSC quiescence. In transplantation settings, niche Tregs prevented allogeneic (allo-) HSC rejection through adenosine and facilitated allo-HSC engraftment. Furthermore, transfer of niche Tregs promoted allo-HSC engraftment to a much greater extent than transfer of other Tregs. These results identify a unique niche-associated Treg subset and adenosine as regulators of HSC quiescence, abundance, and engraftment, further highlighting their therapeutic utility.
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http://dx.doi.org/10.1016/j.stem.2018.01.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6534147PMC
March 2018

Transmission of HBV DNA Mediated by Ceramide-Triggered Extracellular Vesicles.

Cell Mol Gastroenterol Hepatol 2017 Mar 24;3(2):272-283. Epub 2016 Oct 24.

Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan.

Background & Aims: An extracellular vesicle (EV) is a nanovesicle that shuttles proteins, nucleic acids, and lipids, thereby influencing cell behavior. A recent crop of reports have shown that EVs are involved in infectious biology, influencing host immunity and playing a role in the viral life cycle. In the present work, we investigated the EV-mediated transmission of hepatitis B virus (HBV) infection.

Methods: We investigated the EV-mediated transmission of HBV infection by using a HBV infectious culture system that uses primary human hepatocytes derived from humanized chimeric mice (PXB-cells). Purified EVs were isolated by ultracentrifugation. To analyze the EVs and virions, we used stimulated emission depletion microscopy.

Results: Purified EVs from HBV-infected PXB-cells were shown to contain HBV DNA and to be capable of transmitting HBV DNA to naive PXB-cells. These HBV-DNA-transmitting EVs were shown to be generated through a ceramide-triggered EV production pathway. Furthermore, we showed that these HBV-DNA-transmitting EVs were resistant to antibody neutralization; stimulated emission depletion microscopy showed that EVs lacked hepatitis B surface antigen, the target of neutralizing antibodies.

Conclusions: These findings suggest that EVs harbor a DNA cargo capable of transmitting viral DNA into hepatocytes during HBV infection, representing an additional antibody-neutralization-resistant route of HBV infection.
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http://dx.doi.org/10.1016/j.jcmgh.2016.10.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5331779PMC
March 2017

Identification of highly sensitive biomarkers that can aid the early detection of pancreatic cancer using GC/MS/MS-based targeted metabolomics.

Clin Chim Acta 2017 May 16;468:98-104. Epub 2017 Feb 16.

Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Hyogo, Japan; Metabolomics Research, Department of Internal Related, Kobe University Graduate School of Medicine, Hyogo, Japan; AMED-CREST, AMED, Hyogo, Japan. Electronic address:

Background: To improve prognosis of pancreatic cancer (PC) patients, the discovery of more reliable biomarkers for the early detection is desired.

Methods: Blood samples were collected by 2 independent groups. The 1st set was included 55 early PC and 58 healthy volunteers (HV), and the 2nd set was included 16 PC and 16HV. The 16 targeted metabolites were quantitatively analyzed by gas chromatography/tandem mass spectrometry together with their corresponding stable isotopes. In the 1st set, the levels of these metabolites were evaluated, and diagnostic models were constructed via multivariate logistic regression analysis, leading to validation using the 2nd set.

Results: In the 1st set, model X consisting of 4 candidates based on our previous report possessed higher sensitivity (74.1%) than carbohydrate antigen 19-9 (CA19-9). Model Y, consisting of 2 metabolites newly selected from 16 metabolites via stepwise method possessed higher sensitivity (70.4%) than CA19-9. Furthermore, combining model Y with CA19-9 increased its sensitivity (90.7%) and specificity (89.5%). In the 2nd set, combining model Y with CA19-9 displayed high sensitivity (81.3%) and specificity (93.8%). In particular, it displayed very high sensitivity (100%) for resectable PC.

Conclusions: Quantitative analysis confirmed that metabolomics-based diagnostic methods are useful for detecting PC early.
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http://dx.doi.org/10.1016/j.cca.2017.02.011DOI Listing
May 2017

Pancreatic cancer screening using a multiplatform human serum metabolomics system.

Biomark Med 2016 06 12;10(6):577-86. Epub 2016 May 12.

Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan.

Aim: To examine a novel screening method for pancreatic cancer involving gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry-based metabolomics analysis.

Materials & Methods: Sera from pancreatic cancer patients (n = 59) and healthy volunteers (n = 59) were allocated to the training set or validation set. Serum metabolome analysis was carried out using our multiplatform metabolomics system. A diagnostic model was constructed using a two-phase screening method that was newly advocated.

Results: When the training set was used, the constructed diagnostic model exhibited high sensitivity (100%) and specificity (80%) for pancreatic cancer. When the validation set was used, the model displayed high sensitivity (84.1%) and specificity (84.1%).

Conclusion: We successfully developed a diagnostic model for pancreatic cancer using a multiplatform serum metabolomics system.
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http://dx.doi.org/10.2217/bmm-2016-0020DOI Listing
June 2016

MHC Class I Expression by Donor Hematopoietic Stem Cells Is Required to Prevent NK Cell Attack in Allogeneic, but Not Syngeneic Recipient Mice.

PLoS One 2015 6;10(11):e0141785. Epub 2015 Nov 6.

Columbia Center for Translational Immunology, Department of Medicine, Surgery and Microbiology/Immunology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America.

NK cells resist engraftment of syngeneic and allogeneic bone marrow (BM) cells lacking major histocompatibility (MHC) class I molecules, suggesting a critical role for donor MHC class I molecules in preventing NK cell attack against donor hematopoietic stem and progenitor cells (HSPCs), and their derivatives. However, using high-resolution in vivo imaging, we demonstrated here that syngeneic MHC class I knockout (KO) donor HSPCs persist with the same survival frequencies as wild-type donor HSPCs. In contrast, syngeneic MHC class I KO differentiated hematopoietic cells and allogeneic MHC class I KO HSPCs were rejected in a manner that was significantly inhibited by NK cell depletion. In vivo time-lapse imaging demonstrated that mice receiving allogeneic MHC class I KO HSPCs showed a significant increase in NK cell motility and proliferation as well as frequencies of NK cell contact with and killing of HSPCs as compared to mice receiving wild-type HSPCs. The data indicate that donor MHC class I molecules are required to prevent NK cell-mediated rejection of syngeneic differentiated cells and allogeneic HSPCs, but not of syngeneic HSPCs.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0141785PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4636372PMC
June 2016

Novel pH-sensitive multifunctional envelope-type nanodevice for siRNA-based treatments for chronic HBV infection.

J Hepatol 2016 Mar 24;64(3):547-55. Epub 2015 Oct 24.

Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan. Electronic address:

Background & Aims: Antiviral agents including entecavir (ETV) suppress the replication of the hepatitis B virus (HBV) genome in human hepatocytes, but they do not reduce the abundance of viral proteins. The present study focused on effectively reducing viral protein levels.

Methods: We designed siRNAs (HBV-siRNA) that target consensus sequences in HBV genomes. To prevent the emergence of escaped mutant virus, we mixed three HBV-siRNAs (HBV-siRNAmix); the mixture was encapsulated in a novel pH-sensitive multifunctional envelope-type nanodevice (MEND), a hepatocyte-specific drug delivery system. Coagulation factor 7 siRNA was used to assess delivery and knockdown efficiencies of MEND/siRNA treatments in mice. The potency of MEND/HBV-siRNAmix was evaluated in primary human hepatocytes and in chimeric mice with humanized liver persistently infected with HBV.

Results: Effective knockdown of targets, efficient delivery of siRNA, and liver-specific delivery were each observed with MEND. MEND/HBV-siRNA caused efficient reduction of HBsAg and HBeAg in vitro and in vivo. However, ETV treatment did not efficiently reduce HBsAg or HBeAg when compared with a single MEND/HBV-siRNAmix treatment. Furthermore, the suppressive effects of a single dose of MEND/HBV-siRNAmix persisted for 14days in vitro and in vivo.

Conclusion: We demonstrated that MEND/HBV-siRNA controlled HBV more efficiently than did ETV. Furthermore, the effect of a single dose of MEND/HBV-siRNA persisted for a long time. These results indicated that MEND/HBV-siRNA may be a promising novel HBV treatment that is more effective than reverse transcriptase inhibitors.
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http://dx.doi.org/10.1016/j.jhep.2015.10.014DOI Listing
March 2016

[A case of epidermoid cyst in an intrapancreatic accessory spleen showing cyst-in-cyst-like structure mimicking mucinous cystic neoplasm].

Nihon Shokakibyo Gakkai Zasshi 2015 Oct;112(10):1858-67

Department of Gastroenterology, Kobe University Graduate School of Medicine.

In 2010, a 39-year-old woman presented with a cystic lesion, 16 mm in diameter, in the tail of the pancreas. Regular follow-ups were conducted to monitor this lesion; its diameter was found to increase to 45 mm in 2013. Thus, the patient was admitted to our hospital for further examination and treatment. Abdominal US, abdominal contrast-enhanced CT, and MRI showed a cystic lesion of 45 mm in diameter in the tail of the pancreas, which had internal septae and mural nodules inside. EUS revealed a cyst-in-cyst-like structure, with a thickened cystic wall along the entire circumference. Thus, distal pancreatectomy and splenectomy were performed on the basis of a diagnosis of mucinous cystic neoplasm. Histopathological examination of a resected specimen showed that the lesion comprised a substantial component of red-brown tone, with adjacent cystic components. The final diagnosis was an epidermoid cyst in an intrapancreatic accessory spleen.
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http://dx.doi.org/10.11405/nisshoshi.112.1858DOI Listing
October 2015

In vivo therapeutic potential of Dicer-hunting siRNAs targeting infectious hepatitis C virus.

Sci Rep 2014 Apr 23;4:4750. Epub 2014 Apr 23.

Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan.

The development of RNA interference (RNAi)-based therapy faces two major obstacles: selecting small interfering RNA (siRNA) sequences with strong activity, and identifying a carrier that allows efficient delivery to target organs. Additionally, conservative region at nucleotide level must be targeted for RNAi in applying to virus because hepatitis C virus (HCV) could escape from therapeutic pressure with genome mutations. In vitro preparation of Dicer-generated siRNAs targeting a conserved, highly ordered HCV 5' untranslated region are capable of inducing strong RNAi activity. By dissecting the 5'-end of an RNAi-mediated cleavage site in the HCV genome, we identified potent siRNA sequences, which we designate as Dicer-hunting siRNAs (dh-siRNAs). Furthermore, formulation of the dh-siRNAs in an optimized multifunctional envelope-type nano device inhibited ongoing infectious HCV replication in human hepatocytes in vivo. Our efforts using both identification of optimal siRNA sequences and delivery to human hepatocytes suggest therapeutic potential of siRNA for a virus.
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http://dx.doi.org/10.1038/srep04750DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3996463PMC
April 2014

Isolation and characterization of highly replicable hepatitis C virus genotype 1a strain HCV-RMT.

PLoS One 2013 16;8(12):e82527. Epub 2013 Dec 16.

Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.

Multiple genotype 1a clones have been reported, including the very first hepatitis C virus (HCV) clone called H77. The replication ability of some of these clones has been confirmed in vitro and in vivo, although this ability is somehow compromised. We now report a newly isolated genotype 1a clone, designated HCV-RMT, which has the ability to replicate efficiently in patients, chimeric mice with humanized liver, and cultured cells. An authentic subgenomic replicon cell line was established from the HCV-RMT sequence with spontaneous introduction of three adaptive mutations, which were later confirmed to be responsible for efficient replication in HuH-7 cells as both subgenomic replicon RNA and viral genome RNA. Following transfection, the HCV-RMT RNA genome with three adaptive mutations was maintained for more than 2 months in HuH-7 cells. One clone selected from the transfected cells had a high copy number, and its supernatant could infect naïve HuH-7 cells. Direct injection of wild-type HCV-RMT RNA into the liver of chimeric mice with humanized liver resulted in vigorous replication, similar to inoculation with the parental patient's serum. A study of virus replication using HCV-RMT derivatives with various combinations of adaptive mutations revealed a clear inversely proportional relationship between in vitro and in vivo replication abilities. Thus, we suggest that HCV-RMT and its derivatives are important tools for HCV genotype 1a research and for determining the mechanism of HCV replication in vitro and in vivo.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0082527PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3865021PMC
September 2014

A serine palmitoyltransferase inhibitor blocks hepatitis C virus replication in human hepatocytes.

Gastroenterology 2013 Oct 18;145(4):865-73. Epub 2013 Jun 18.

Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan; Research Division, Chugai Pharmaceutical Co., Ltd., Tokyo, Japan.

Background & Aims: Host cell lipid rafts form a scaffold required for replication of hepatitis C virus (HCV). Serine palmitoyltransferases (SPTs) produce sphingolipids, which are essential components of the lipid rafts that associate with HCV nonstructural proteins. Prevention of the de novo synthesis of sphingolipids by an SPT inhibitor disrupts the HCV replication complex and thereby inhibits HCV replication. We investigated the ability of the SPT inhibitor NA808 to prevent HCV replication in cells and mice.

Methods: We tested the ability of NA808 to inhibit SPT's enzymatic activity in FLR3-1 replicon cells. We used a replicon system to select for HCV variants that became resistant to NA808 at concentrations 4- to 6-fold the 50% inhibitory concentration, after 14 rounds of cell passage. We assessed the ability of NA808 or telaprevir to inhibit replication of HCV genotypes 1a, 1b, 2a, 3a, and 4a in mice with humanized livers (transplanted with human hepatocytes). NA808 was injected intravenously, with or without pegylated interferon alfa-2a and HCV polymerase and/or protease inhibitors.

Results: NA808 prevented HCV replication via noncompetitive inhibition of SPT; no resistance mutations developed. NA808 prevented replication of all HCV genotypes tested in mice with humanized livers. Intravenous NA808 significantly reduced viral load in the mice and had synergistic effects with pegylated interferon alfa-2a and HCV polymerase and protease inhibitors.

Conclusions: The SPT inhibitor NA808 prevents replication of HCV genotypes 1a, 1b, 2a, 3a, and 4a in cultured hepatocytes and in mice with humanized livers. It might be developed for treatment of HCV infection or used in combination with pegylated interferon alfa-2a or HCV polymerase or protease inhibitors.
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http://dx.doi.org/10.1053/j.gastro.2013.06.012DOI Listing
October 2013

Targeted induction of interferon-λ in humanized chimeric mouse liver abrogates hepatotropic virus infection.

PLoS One 2013 28;8(3):e59611. Epub 2013 Mar 28.

Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan.

Background & Aims: The interferon (IFN) system plays a critical role in innate antiviral response. We presume that targeted induction of IFN in human liver shows robust antiviral effects on hepatitis C virus (HCV) and hepatitis B virus (HBV).

Methods: This study used chimeric mice harboring humanized livers and infected with HCV or HBV. This mouse model permitted simultaneous analysis of immune responses by human and mouse hepatocytes in the same liver and exploration of the mechanism of antiviral effect against these viruses. Targeted expression of IFN was induced by treating the animals with a complex comprising a hepatotropic cationic liposome and a synthetic double-stranded RNA analog, pIC (LIC-pIC). Viral replication, IFN gene expression, IFN protein production, and IFN antiviral activity were analyzed (for type I, II and III IFNs) in the livers and sera of these humanized chimeric mice.

Results: Following treatment with LIC-pIC, the humanized livers of chimeric mice exhibited increased expression (at the mRNA and protein level) of human IFN-λs, resulting in strong antiviral effect on HBV and HCV. Similar increases were not seen for human IFN-α or IFN-β in these animals. Strong induction of IFN-λs by LIC-pIC occurred only in human hepatocytes, and not in mouse hepatocytes nor in human cell lines derived from other (non-hepatic) tissues. LIC-pIC-induced IFN-λ production was mediated by the immune sensor adaptor molecules mitochondrial antiviral signaling protein (MAVS) and Toll/IL-1R domain-containing adaptor molecule-1 (TICAM-1), suggesting dual recognition of LIC-pIC by both sensor adaptor pathways.

Conclusions: These findings demonstrate that the expression and function of various IFNs differ depending on the animal species and tissues under investigation. Chimeric mice harboring humanized livers demonstrate that IFN-λs play an important role in the defense against human hepatic virus infection.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0059611PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3610702PMC
September 2013

Cationic-cellulose nanofibers: preparation and dyeability with anionic reactive dyes for apparel application.

Carbohydr Polym 2013 Jan 22;91(1):434-43. Epub 2012 Aug 22.

Nano Fusion Technology Research Group, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan.

Continuous effort in research and development of nanofibers for apparel usage has been focused within their functional properties only. We investigated esthetic properties by producing colored cationic-cellulose nanofibers for the very first time for the potential application of apparel use. The cellulose acetate nanofibers were electrospun followed by deacetylation and cationization to produce functional cationic-cellulose nanofibers and then dyed with anionic reactive dyes. The spectrophotometric measurement of dyed samples was carried out to determine color coordinates and color yield values. The cationic-cellulose nanofibers showed enhanced color yield and dye fixation without addition of an electrolyte in comparison to cellulose nanofibers. The cationization of cellulose nanofibers significantly enhanced the color yield values of around 76% at dye concentrations of 5%. Excellent color fastness results demonstrate that these new colored and breathable materials can potentially be considered as future apparel for casual or fashion.
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http://dx.doi.org/10.1016/j.carbpol.2012.08.046DOI Listing
January 2013

Self-enhancement of hepatitis C virus replication by promotion of specific sphingolipid biosynthesis.

PLoS Pathog 2012 16;8(8):e1002860. Epub 2012 Aug 16.

Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan.

Lipids are key components in the viral life cycle that affect host-pathogen interactions. In this study, we investigated the effect of HCV infection on sphingolipid metabolism, especially on endogenous SM levels, and the relationship between HCV replication and endogenous SM molecular species. We demonstrated that HCV induces the expression of the genes (SGMS1 and 2) encoding human SM synthases 1 and 2. We observed associated increases of both total and individual sphingolipid molecular species, as assessed in human hepatocytes and in the detergent-resistant membrane (DRM) fraction in which HCV replicates. SGMS1 expression had a correlation with HCV replication. Inhibition of sphingolipid biosynthesis with a hepatotropic serine palmitoyltransferase (SPT) inhibitor, NA808, suppressed HCV-RNA production while also interfering with sphingolipid metabolism. Further, we identified the SM molecular species that comprise the DRM fraction and demonstrated that these endogenous SM species interacted with HCV nonstructural 5B polymerase to enhance viral replication. Our results reveal that HCV alters sphingolipid metabolism to promote viral replication, providing new insights into the formation of the HCV replication complex and the involvement of host lipids in the HCV life cycle.
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http://dx.doi.org/10.1371/journal.ppat.1002860DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3420934PMC
December 2012

An orally available, small-molecule interferon inhibits viral replication.

Sci Rep 2012 10;2:259. Epub 2012 Feb 10.

Kamakura Research Laboratories, Chugai Pharmaceutical Co. Ltd., Kamakura, Kanagawa, Japan.

Most acute hepatitis C virus (HCV) infections become chronic and some progress to liver cirrhosis or hepatocellular carcinoma. Standard therapy involves an interferon (IFN)-α-based regimen, and efficacy of therapy has been significantly improved by the development of protease inhibitors. However, several issues remain concerning the injectable form and the side effects of IFN. Here, we report an orally available, small-molecule type I IFN receptor agonist that directly transduces the IFN signal cascade and stimulates antiviral gene expression. Like type I IFN, the small-molecule compound induces IFN-stimulated gene (ISG) expression for antiviral activity in vitro and in vivo in mice, and the ISG induction mechanism is attributed to a direct interaction between the compound and IFN-α receptor 2, a key molecule of IFN-signaling on the cell surface. Our study highlights the importance of an orally active IFN-like agent, both as a therapy for antiviral infections and as a potential IFN substitute.
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http://dx.doi.org/10.1038/srep00259DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3277087PMC
April 2013

Interactions between dyes and surfactants in inkjet ink used for textiles.

J Oleo Sci 2011 ;60(12):627-37

Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan.

Optimal preparation of inkjet ink should be possible through the elucidation of the relationship between dye/additive interactions and ink performance. In the present study, the interactions between the dyes and surfactant additives were investigated. To investigate the physical properties of the surfactants used, the critical micelle concentration (cmc) and the aggregation number (N) were determined using electron spin resonance, static light-scattering, and fluorescence spectroscopy. On the basis of the cmc and N values, the visible absorption spectra of aqueous acid dye solutions (C. I. Acid Red 88, 13, and 27) containing surfactants (i.e., Surfynol 465 (S465), octaethylene glycol monododecyl ether (OGDE), and sodium dodecyl sulfate (SDS)) were measured. From the dependence of the spectra on the surfactant concentration, the binding constants, K(bind), of the acid dyes with the surfactant micelles were calculated: the K(bind) values decreased in the order of C. I. Acid Red 88 > C. I. Acid Red 13 > C. I. Acid Red 27, which correlates with the number of sulfonate groups. For all the dyes, the K(bind) values with the nonionic surfactants, S465 and OGDE, were much larger than those with the anionic surfactant, SDS. The thermodynamic parameters of the binding, i.e., the enthalpy change, ΔH(bind), and entropy change, ΔS(bind), were determined via the temperature dependence of the binding constants. The positive ΔH(bind) value for S465 indicates an endothermic binding process, while the negative ΔH(bind) values for SDS and OGDE indicate exothermic binding processes.
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http://dx.doi.org/10.5650/jos.60.627DOI Listing
March 2012

Monoclonal antibody 2-152a suppresses hepatitis C virus infection through betaine/GABA transporter-1.

J Infect Dis 2011 Oct;204(8):1172-80

Department of Experimental Phylaxiology, Faculty of Life Sciences, Kumamoto University, Honjo Kumamoto City, Japan.

Background: We recently established a monoclonal antibody (2-152a MAb) that binds to 3β-hydroxysterol-Δ24-reductase (DHCR24) by immunizing mice with cells (RzM6-LC) persistently expressing hepatitis C virus (HCV). Here, we aimed to analyze the activity of 2-152a MAb against HCV replication and explore the molecular mechanism underlying the antiviral activity.

Methods: We characterized the effects of 2-152a MAb on HCV replication and performed a microarray analysis of antibody-treated HCV replicon cells. The molecules showing a significant change after the antibody treatment were screened to examine their relationship with HCV replication.

Results: The antibody had antiviral activity both in vitro and in vivo (chimeric mice). In the microarray analysis, 2-152a MAb significantly suppressed the expression of betaine/GABA transporter-1 (BGT-1) in 2 HCV replicon cell lines but not in HCV-cured cells. Silencing of BGT-1 expression by small interfering RNA (siRNA) revealed significant suppression of HCV replication and infection without cytotoxicity. Further, BGT-1 expression was significantly increased in the presence of HCV (P < .05).

Conclusions: Our results suggest that 2-152a MAb suppresses HCV replication and infection through BGT-1. These findings highlight important roles of BGT-1 in HCV replication and reveal a possible target for anti-HCV therapy.
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http://dx.doi.org/10.1093/infdis/jir501DOI Listing
October 2011

Augmentation of DHCR24 expression by hepatitis C virus infection facilitates viral replication in hepatocytes.

J Hepatol 2011 Sep 22;55(3):512-521. Epub 2010 Dec 22.

Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.

Background & Aims: We characterized the role of 24-dehydrocholesterol reductase (DHCR24) in hepatitis C virus infection (HCV). DHCR24 is a cholesterol biosynthetic enzyme and cholesterol is a major component of lipid rafts, which is reported to play an important role in HCV replication. Therefore, we examined the potential of DHCR24 as a target for novel HCV therapeutic agents.

Methods: We examined DHCR24 expression in human hepatocytes in both the livers of HCV-infected patients and those of chimeric mice with human hepatocytes. We targeted DHCR24 with siRNA and U18666A which is an inhibitor of both DHCR24 and cholesterol synthesis. We measured the level of HCV replication in these HCV replicon cell lines and HCV infected cells. U18666A was administrated into chimeric mice with humanized liver, and anti-viral effects were assessed.

Results: Expression of DHCR24 was induced by HCV infection in human hepatocytes in vitro, and in human hepatocytes of chimeric mouse liver. Silencing of DHCR24 by siRNA decreased HCV replication in replicon cell lines and HCV JFH-1 strain-infected cells. Treatment with U18666A suppressed HCV replication in the replicon cell lines. Moreover, to evaluate the anti-viral effect of U18666A in vivo, we administrated U18666A with or without pegylated interferon to chimeric mice and observed an inhibitory effect of U18666A on HCV infection and a synergistic effect with interferon.

Conclusions: DHCR24 is an essential host factor which augmented its expression by HCV infection, and plays a significant role in HCV replication. DHCR24 may serve as a novel anti-HCV drug target.
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http://dx.doi.org/10.1016/j.jhep.2010.12.011DOI Listing
September 2011

Sphingomyelin activates hepatitis C virus RNA polymerase in a genotype-specific manner.

J Virol 2010 Nov 15;84(22):11761-70. Epub 2010 Sep 15.

Institut Pasteur of Shanghai, Chinese Academy of Sciences, 200025 Shanghai, People's Republic of China.

Hepatitis C virus (HCV) replication and infection depend on the lipid components of the cell, and replication is inhibited by inhibitors of sphingomyelin biosynthesis. We found that sphingomyelin bound to and activated genotype 1b RNA-dependent RNA polymerase (RdRp) by enhancing its template binding activity. Sphingomyelin also bound to 1a and JFH1 (genotype 2a) RdRps but did not activate them. Sphingomyelin did not bind to or activate J6CF (2a) RdRp. The sphingomyelin binding domain (SBD) of HCV RdRp was mapped to the helix-turn-helix structure (residues 231 to 260), which was essential for sphingomyelin binding and activation. Helix structures (residues 231 to 241 and 247 to 260) are important for RdRp activation, and 238S and 248E are important for maintaining the helix structures for template binding and RdRp activation by sphingomyelin. 241Q in helix 1 and the negatively charged 244D at the apex of the turn are important for sphingomyelin binding. Both amino acids are on the surface of the RdRp molecule. The polarity of the phosphocholine of sphingomyelin is important for HCV RdRp activation. However, phosphocholine did not activate RdRp. Twenty sphingomyelin molecules activated one RdRp molecule. The biochemical effect of sphingomyelin on HCV RdRp activity was virologically confirmed by the HCV replicon system. We also found that the SBD was the lipid raft membrane localization domain of HCV NS5B because JFH1 (2a) replicon cells harboring NS5B with the mutation A242C/S244D moved to the lipid raft while the wild type did not localize there. This agreed with the myriocin sensitivity of the mutant replicon. This sphingomyelin interaction is a target for HCV infection because most HCV RdRps have 241Q.
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http://dx.doi.org/10.1128/JVI.00638-10DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2977884PMC
November 2010

[Suppression of hepatitis C virus (HCV) replication with serine palmitoyltransferase inhibitor].

Yakugaku Zasshi 2010 Feb;130(2):157-61

Department of Microbiology and Cell biology, The Tokyo metropolitan Institute of Medical Science, Tokyo, Japan.

Hepatitis C virus (HCV) persists chronically in most infected patients, eventually causing chronic hepatitis, liver cirrhosis, and in some cases hepatocellular carcinoma. The combination therapy of PEG-IFN and ribavirin improves efficacy in many patients, although it does not lead to sufficient achievements in genotype 1b patients. To aid in invention of new anti-HCV reagents, we focused on host factors that contributed to HCV lifecycle. We identified serine palmitoyltransferase inhibitor as an anti-HCV reagent through high-throughput screening using HCV replicon cells. We investigated the mechanism of anti-HCV effect of SPT inhibitor. It has been reported that sphingolipids and cholesterol compose the lipid raft where replication of HCV occurs. We investigated the influence of SPT inhibitor to lipid rafts by analyzing the detergent-resistant membrane (DRM). The analysis showed that SPT inhibitor moved HCV RNA-dependent RNA polymerase (NS5B) to detergent-soluble fraction from DRM, and Biacore analysis indicated binding of sphingomyelin to NS5B. These results suggest that SPT inhibitor disrupts the interaction between NS5B and sphingomyelin. Moreover, we evaluated the anti-HCV effect of SPT inhibitor in vivo with humanized chimeric mice. SPT inhibitor led to rapid decline in serum HCV-RNA of about 1-2 log within 8 days. Furthermore, combination therapy of SPT inhibitor and PEG-IFN achieved about 3 log reduction in serum HCV-RNA.
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http://dx.doi.org/10.1248/yakushi.130.157DOI Listing
February 2010

Hepatitis C virus impairs p53 via persistent overexpression of 3beta-hydroxysterol Delta24-reductase.

J Biol Chem 2009 Dec 27;284(52):36442-36452. Epub 2009 Oct 27.

Department of Experimental Phylaxiology, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto, Kumamoto 860-8556, Japan. Electronic address:

Persistent infection with hepatitis C virus (HCV) induces tumorigenicity in hepatocytes. To gain insight into the mechanisms underlying this process, we generated monoclonal antibodies on a genome-wide scale against an HCV-expressing human hepatoblastoma-derived cell line, RzM6-LC, showing augmented tumorigenicity. We identified 3beta-hydroxysterol Delta24-reductase (DHCR24) from this screen and showed that its expression reflected tumorigenicity. HCV induced the DHCR24 overexpression in human hepatocytes. Ectopic or HCV-induced DHCR24 overexpression resulted in resistance to oxidative stress-induced apoptosis and suppressed p53 activity. DHCR24 overexpression in these cells paralleled the increased interaction between p53 and MDM2 (also known as HDM2), a p53-specific E3 ubiquitin ligase, in the cytoplasm. Persistent DHCR24 overexpression did not alter the phosphorylation status of p53 but resulted in decreased acetylation of p53 at lysine residues 373 and 382 in the nucleus after treatment with hydrogen peroxide. Taken together, these results suggest that DHCR24 is elevated in response to HCV infection and inhibits the p53 stress response by stimulating the accumulation of the MDM2-p53 complex in the cytoplasm and by inhibiting the acetylation of p53 in the nucleus.
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http://dx.doi.org/10.1074/jbc.M109.043232DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2794760PMC
December 2009

Pathogenesis of hepatitis C virus infection in Tupaia belangeri.

J Virol 2010 Jan;84(1):303-11

Department of Microbiology and Cell Biology, The Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya-ku, Tokyo 156-0057, Japan.

The lack of a small-animal model has hampered the analysis of hepatitis C virus (HCV) pathogenesis. The tupaia (Tupaia belangeri), a tree shrew, has shown susceptibility to HCV infection and has been considered a possible candidate for a small experimental model of HCV infection. However, a longitudinal analysis of HCV-infected tupaias has yet to be described. Here, we provide an analysis of HCV pathogenesis during the course of infection in tupaias over a 3-year period. The animals were inoculated with hepatitis C patient serum HCR6 or viral particles reconstituted from full-length cDNA. In either case, inoculation caused mild hepatitis and intermittent viremia during the acute phase of infection. Histological analysis of infected livers revealed that HCV caused chronic hepatitis that worsened in a time-dependent manner. Liver steatosis, cirrhotic nodules, and accompanying tumorigenesis were also detected. To examine whether infectious virus particles were produced in tupaia livers, naive animals were inoculated with sera from HCV-infected tupaias, which had been confirmed positive for HCV RNA. As a result, the recipient animals also displayed mild hepatitis and intermittent viremia. Quasispecies were also observed in the NS5A region, signaling phylogenic lineage from the original inoculating sequence. Taken together, these data suggest that the tupaia is a practical animal model for experimental studies of HCV infection.
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http://dx.doi.org/10.1128/JVI.01448-09DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2798454PMC
January 2010

[Suppression of hepatitis C virus with the reagent targetting host factors].

Uirusu 2008 Dec;58(2):207-13

Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8613, Japan.

Hepatitis C virus (HCV) develops persistent infection in most infected patients, and eventually cause chronic hepatitis, liver cirrhosis and then hepatocellular carcinoma. The combination therapy of PEG-IFN and ribavirin improves the efficacy in many patients, while it does not lead to sufficient achievements in genotype1b patients. To invent new anti-HCV reagent, we focused on host factors which HCV take advantage of in its life-cycle. We identified serine palmitoyltransferase inhibitor as anti-HCV reagent through high-through put screenig using HCV replicon cells. Moreover, we evaluate the anti-HCV effect of SPT-inhibitor in vivo with humanized chimeric mice. SPT-inhibitor led to rapid decline in serum HCV-RNA of about 1-2log within 8 day, futhermore the combination therapy of SPT-inhibitor and PEG-IFN achieved about 3log reduction in serum HCV-RNA. At last, we investigated the mechanism of anti-HCV effect of SPT-inhibitor. It has been reported that sphingolipids and cholesterol compose the lipid raft, in which the replication of HCV occur. We investigated the influence of SPT-inhibitor to lipid rafts by analysing the detergent resistant membrane (DRM). The analysis proved that SPT inhibitor got HCV RNA dependent RNA polymerase (NS5B) to move to detergent soluble fraction from DRM, and Biacore analysis indicated the binding of sphingomyelin to NS5B. These results suggested SPT inhibitor got NS5B to release from replication complex.
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http://dx.doi.org/10.2222/jsv.58.207DOI Listing
December 2008

Identification of ROBO1 as a novel hepatocellular carcinoma antigen and a potential therapeutic and diagnostic target.

Clin Cancer Res 2006 Jun;12(11 Pt 1):3257-64

Genome Science Division, Research Center for Advanced Science and Technology, the University of Tokyo, Japan.

Purpose: Hepatocellular carcinoma is the most common primary malignancy of the liver and accounts for as many as one million deaths annually worldwide. The present study was done to identify new transmembrane molecules for antibody therapy in hepatocellular carcinoma.

Experimental Design: Gene expression profiles of pooled total RNA from three tissues each of moderately differentiated and poorly differentiated hepatocellular carcinoma were compared with those of normal liver, noncancerous liver tissue in hepatocellular carcinoma patients, 30 normal tissue samples, and five fetal tissue samples. Target genes up-regulated specifically in hepatocellular carcinoma were validated by immunohistochemical analysis and complement-dependent cytotoxicity assay using monoclonal antibodies generated against target molecules.

Results: The human homologue of the Drosophila Roundabout gene, axon guidance receptor homologue 1, ROBO1/DUTT1, a member of the immunoglobulin superfamily, was highly expressed in hepatocellular carcinoma, whereas it showed only a limited distribution in normal tissues. On immunohistochemical analysis using a newly generated anti-ROBO1 monoclonal antibody, positive signals were observed in 83 of 98 cases of hepatocellular carcinoma (84.7%). The mAb B2318C induced complement-dependent cytotoxicity in ROBO1-expressing cell lines and in the liver cancer cell line PLC/PRF/5. Strikingly, the ectodomain of ROBO1 was detected not only in the culture medium of liver cancer cell lines (PLC/PRF/5, HepG2, etc.) but also in sera from hepatocellular carcinoma patients (6 of 11).

Conclusions: This is the first report that ROBO1 is overexpressed in hepatocellular carcinoma and shed into serum in humans. These observations suggest that ROBO1 is a potential new serologic marker for hepatocellular carcinoma and may represent a new therapeutic target.
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http://dx.doi.org/10.1158/1078-0432.CCR-05-2787DOI Listing
June 2006

2D7 diabody bound to the alpha2 domain of HLA class I efficiently induces caspase-independent cell death against malignant and activated lymphoid cells.

Biochem Biophys Res Commun 2004 Dec;325(4):1201-9

Genome Antibody Product Research Department, Chugai Pharmaceutical Co., Ltd., Japan.

A mouse monoclonal antibody (2D7 mAb), which specifically bound to the alpha2 domain of HLA class I, rapidly induces cell aggregation accompanied by weak cytotoxicity against ARH-77 cells, suggesting that 2D7 mAb had a potential for agonist antibody. In order to enhance this cytotoxicity, 2D7 mAb was engineered to be a small bivalent antibody fragment, 2D7 diabody. The resultant 2D7 diabody showed a strong cytotoxicity against ARH-77 cells. As a notable characteristic feature, the lethal effect of 2D7 diabody was quite rapid, mediated by a caspase-independent death pathway. Furthermore, 2D7 diabody also showed cytotoxicity against several leukemia and lymphoma cell lines, and mitogen-activated peripheral blood mononuclear cells (PBMC), but not for normal resting PBMC and adherent cell lines such as HUVEC. These results suggest that 2D7 diabody could be expected as a novel therapeutic antibody for hematological malignancies as well as inflammatory diseases.
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http://dx.doi.org/10.1016/j.bbrc.2004.10.163DOI Listing
December 2004
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