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Sato K, Sato M, Audhya A, Oegema K, Schweinsberg P, Grant BD. Dynamic regulation of caveolin-1 trafficking in the germ line and embryo of Caenorhabditis elegans. Mol Biol Cell 2006; 17:3085-94. [PMID: 16672374 PMCID: PMC1483042 DOI: 10.1091/mbc.e06-03-0211] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2006] [Revised: 04/19/2006] [Accepted: 04/24/2006] [Indexed: 11/11/2022] [Imported: 10/24/2024] Open
Abstract
Caveolin is the major protein component required for the formation of caveolae on the plasma membrane. Here we show that trafficking of Caenorhabditis elegans caveolin-1 (CAV-1) is dynamically regulated during development of the germ line and embryo. In oocytes a CAV-1-green fluorescent protein (GFP) fusion protein is found on the plasma membrane and in large vesicles (CAV-1 bodies). After ovulation and fertilization the CAV-1 bodies fuse with the plasma membrane in a manner reminiscent of cortical granule exocytosis as described in other species. Fusion of CAV-1 bodies with the plasma membrane appears to be regulated by the advancing cell cycle, and not fertilization per se, because fusion can proceed in spe-9 fertilization mutants but is blocked by RNA interference-mediated knockdown of an anaphase-promoting complex component (EMB-27). After exocytosis, most CAV-1-GFP is rapidly endocytosed and degraded within one cell cycle. CAV-1 bodies in oocytes appear to be produced by the Golgi apparatus in an ARF-1-dependent, clathrin-independent, mechanism. Conversely endocytosis and degradation of CAV-1-GFP in embryos requires clathrin, dynamin, and RAB-5. Our results demonstrate that the distribution of CAV-1 is highly dynamic during development and provides new insights into the sorting mechanisms that regulate CAV-1 localization.
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Research Support, N.I.H., Extramural |
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Sato K, Ishikawa T, Okumura A, Yamauchi T, Sato S, Ayada M, Matsumoto E, Hotta N, Oohashi T, Fukuzawa Y, Kakumu S. Expression of Toll-like receptors in chronic hepatitis C virus infection. J Gastroenterol Hepatol 2007; 22:1627-1632. [PMID: 17845690 DOI: 10.1111/j.1440-1746.2006.04783.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] [Imported: 10/24/2024]
Abstract
BACKGROUND Toll-like receptors (TLRs) are involved in innate immunity. Certain viruses interact with TLRs and mediate antiviral effects as well as immune responses. The aim of this study was to investigate the effect of TLRs on pathogenesis in hepatitis C virus (HCV)-infected patients. METHODS Peripheral blood mononuclear cells (PBMC) and CD14+ (monocytes) or CD14- cells from 25 patients with chronic liver disease and 15 healthy subjects were studied for expression of TLRs 2-9 and cytokines of extracted RNA using real-time PCR. Then TLR expression was examined in HepG2 cells transfected with entire or parts (core-NS3, NS3-NS5B) of the HCV open reading frame. TLR expression was calculated as the relative mRNA levels. RESULTS Expression of TLRs 4, 7 and 8 in CD14+ cells of PBMC was increased in patients. Levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-12 p35 for PBMC were also increased in patients. When PBMC were incubated with HCV core protein, enhancement of TLR2 expression and suppression of TLR4 and TLR7 were noted in patients. Similar alteration of TLRs expression was observed in controls. Among HepG2 transfectants, only TLR3 expression was changed; it was suppressed in entire gene transfectant and enhanced in core-NS3 transfectant. Expression of some proteins related to the TLR signaling pathway was suppressed in the entire gene transfectant. CONCLUSIONS The results suggest a correlation between expression levels of TLRs and cytokines, and chronic HCV infection. TLR3 recognizes double-stranded RNA and induces type 1 interferon synthesis. Collectively, suppressed expression of TLR3 in cells transfected with entire HCV may be responsible for continuous HCV infection, although a part of the HCV gene enhances its expression.
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Sato K, Ernstrom GG, Watanabe S, Weimer RM, Chen CH, Sato M, Siddiqui A, Jorgensen EM, Grant BD. Differential requirements for clathrin in receptor-mediated endocytosis and maintenance of synaptic vesicle pools. Proc Natl Acad Sci U S A 2009; 106:1139-44. [PMID: 19151157 PMCID: PMC2633560 DOI: 10.1073/pnas.0809541106] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2008] [Indexed: 11/18/2022] [Imported: 10/24/2024] Open
Abstract
Clathrin is a coat protein involved in vesicle budding from several membrane-bound compartments within the cell. Here we present an analysis of a temperature-sensitive (ts) mutant of clathrin heavy chain (CHC) in a multicellular animal. As expected Caenorhabditis elegans chc-1(b1025ts) mutant animals are defective in receptor-mediated endocytosis and arrest development soon after being shifted to the restrictive temperature. Steady-state clathrin levels in these mutants are reduced by more than 95% at all temperatures. Hub interactions and membrane associations are lost at the restrictive temperature. chc-1(b1025ts) animals become paralyzed within minutes of exposure to the restrictive temperature because of a defect in the nervous system. Surprisingly synaptic vesicle number is not reduced in chc-1(b1025ts) animals. Consistent with the normal number of vesicles, postsynaptic miniature currents occur at normal frequencies. Taken together, these results indicate that a high level of CHC activity is required for receptor-mediated endocytosis in nonneuronal cells but is largely dispensable for maintenance of synaptic vesicle pools.
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Research Support, N.I.H., Extramural |
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Sato K, Norris A, Sato M, Grant BD. C. elegans as a model for membrane traffic. WORMBOOK : THE ONLINE REVIEW OF C. ELEGANS BIOLOGY 2014:1-47. [PMID: 24778088 PMCID: PMC4096984 DOI: 10.1895/wormbook.1.77.2] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] [Imported: 10/24/2024]
Abstract
The counterbalancing action of the endocytosis and secretory pathways maintains a dynamic equilibrium that regulates the composition of the plasma membrane, allowing it to maintain homeostasis and to change rapidly in response to alterations in the extracellular environment and/or intracellular metabolism. These pathways are intimately integrated with intercellular signaling systems and play critical roles in all cells. Studies in Caenorhabditis elegans have revealed diverse roles of membrane trafficking in physiology and development and have also provided molecular insight into the fundamental mechanisms that direct cargo sorting, vesicle budding, and membrane fisson and fusion. In this review, we summarize progress in understanding membrane trafficking mechanisms derived from work in C. elegans, focusing mainly on work done in non-neuronal cell-types, especially the germline, early embryo, coelomocytes, and intestine.
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Research Support, N.I.H., Extramural |
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Sato K, Kimura F, Nakamura Y, Murakami H, Yoshida M, Tanaka M, Nagata S, Kanatani Y, Wakimoto N, Nagata N, Motoyoshi K. An aggressive nasal lymphoma accompanied by high levels of soluble Fas ligand. Br J Haematol 1996; 94:379-382. [PMID: 8759901 DOI: 10.1046/j.1365-2141.1996.d01-1799.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] [Imported: 10/24/2024]
Abstract
Fas ligand (FasL), either in the membrane bound form or soluble form, has cytotoxic activity against Fas-expressing cells. We report a case of nasal lymphoma accompanied by liver damage and pancytopenia. The serum level of soluble FasL (sFasL) was very high on admission, but rapidly decreased to normal levels after chemotherapy for lymphoma. Liver damage and pancytopenia also improved with the decrease in serum sFasL. Since Fas is expressed on both hepatocytes and haemopoietic cells, these facts suggest that FasL was expressed on lymphoma cells and directly associated with pathogenesis of liver damage and pancytopenia through its cytotoxic activity.
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Case Reports |
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Sato K, Sato M. Multiple ways to prevent transmission of paternal mitochondrial DNA for maternal inheritance in animals. J Biochem 2017; 162:247-253. [PMID: 28981751 DOI: 10.1093/jb/mvx052] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 06/10/2017] [Indexed: 11/14/2022] [Imported: 10/24/2024] Open
Abstract
Mitochondria contain their own DNA (mtDNA). In most sexually reproducing organisms, mtDNA is inherited maternally (uniparentally); this type of inheritance is thus referred to as 'maternal (uniparental) inheritance'. Recent studies have revealed various mechanisms to prevent the transmission of sperm-derived paternal mtDNA to the offspring, thereby ensuring maternal inheritance of mtDNA. In the nematode Caenorhabditis elegans, paternal mitochondria and their mtDNA degenerate almost immediately after fertilization and are selectively degraded by autophagy, which is referred to as 'allophagy' (allogeneic [non-self] organelle autophagy). In the fruit fly Drosophila melanogaster, paternal mtDNA is largely eliminated by an endonuclease G-mediated mechanism. Paternal mitochondria are subsequently removed by endocytic and autophagic pathways after fertilization. In many mammals, including humans, paternal mitochondria enter fertilized eggs. However, the fate of paternal mitochondria and their mtDNA in mammals is still a matter of debate. In this review, we will summarize recent knowledge on the molecular mechanisms underlying the prevention of paternal mtDNA transmission, which ensures maternal mtDNA inheritance in animals.
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Review |
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Sato K, Simon MD, Levin AM, Shokat KM, Weiss GA. Dissecting the Engrailed homeodomain-DNA interaction by phage-displayed shotgun scanning. CHEMISTRY & BIOLOGY 2004; 11:1017-1023. [PMID: 15271360 DOI: 10.1016/j.chembiol.2004.05.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2004] [Revised: 05/07/2004] [Accepted: 05/12/2004] [Indexed: 11/28/2022] [Imported: 10/15/2024]
Abstract
Phage-displayed alanine shotgun scanning was used to dissect contributions by engrailed homedomain (En-HD) residues 17 through 46, which indirectly influence recognition of DNA. The relative contributions of such indirect contacts, quantified by shotgun scanning, highlight previously unexplored En-HD residues. Two motifs dominate En-HD function in this region. First, two surface-exposed aromatic residues (F20 and Y25) bracket the hydrophobic core. Second, two sets of turn-forming residues are highlighted, including carboxamide-requiring residues E22/N23 and a leucine/isoleucine splint. The En-HD hydrophobic core exhibits a surprising degree of malleability, as demonstrated by homolog shotgun scanning. Most selectants from in vitro shotgun scanning mirror the consensus human homeodomain sequence. Thus, natural evolution and in vitro selection use similar selection criteria: affinity, specificity, and stability. However, homolog shotgun scanning identified mutations capable of improving the affinity and specificity of En-HD.
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Sato K, Mori M. Current and novel therapies for hepatitis B virus infection. Mini Rev Med Chem 2010; 10:20-31. [PMID: 20380640 DOI: 10.2174/138955710791112613] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] [Imported: 10/24/2024]
Abstract
Many therapeutic reagents for hepatitis B virus infection have established efficacy in goals such as alanine aminotransferase normalization, hepatitis B virus DNA suppression, HBeAg seroconversion, histological improvement, and reduce disease progression. However, it is not established that the efficacy of these reagents for the long-term survival and prevention of hepatocellular carcinoma although recent meta-analyses have also shown antiviral therapy to be efficacious. This article reviews the current status and innovative new options for antiviral therapy for hepatitis B and also discusses the various mechanisms of action for each drug, the results of clinical studies for each therapy, and the problems yet to be solved with respect to hepatitis B treatment.
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Review |
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Sato K, Chayama K, Alves K, Toyoda H, Suzuki F, Kato K, Rodrigues L, Zhang X, Setze C, Pilot-Matias T, Burroughs M, Redman R, Kumada H. Randomized Phase 3 Trial of Ombitasvir/Paritaprevir/Ritonavir and Ribavirin for Hepatitis C Virus Genotype 2-Infected Japanese Patients. Adv Ther 2017; 34:1449-1465. [PMID: 28536999 DOI: 10.1007/s12325-017-0506-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Indexed: 12/11/2022] [Imported: 10/15/2024]
Abstract
INTRODUCTION In Japan, hepatitis C virus (HCV) genotype (GT) 2 accounts for approximately 32% of HCV infections. Limited treatment options exist in Japan for HCV GT2-infected patients. GIFT-II was a phase 3, randomized, open-label study evaluating the efficacy and safety of 16- and 12-week regimens of co-formulated ombitasvir (OBV)/paritaprevir (PTV)/ritonavir (r) plus ribavirin (RBV) in Japanese adults with HCV GT2 infection. METHODS Patients were randomized in a 1:1 ratio to once-daily, co-formulated OBV/PTV/r (25/150/100 mg) with weight-based RBV for 16 or 12 weeks. The primary efficacy endpoint was the sustained virologic response at 12 weeks post-treatment (SVR12) rate in the primary efficacy population of non-cirrhotic treatment-naive patients. RESULTS A total of 171 patients were randomized to OBV/PTV/r + RBV. In the primary efficacy population, SVR12 rates were 91.5% (43/47; 95% confidence interval 83.5-99.5%) and 75.0% (36/48; 95% confidence interval 62.8-87.2%) in the 16-week arm and 12-week arm, respectively. No patient in the 16-week arm relapsed by post-treatment week 12. Among non-cirrhotic treatment-experienced patients, the overall SVR rate in the 16-week arm was 75.8% (25/33) and was highest [93.8% (15/16)] among those who had relapsed after previous interferon-based therapy. SVR12 rates were consistently higher in patients with HCV GT2a infection versus HCV GT2b infection [16-week treatment arm: 93.9% (31/33) versus 85.7% (12/14) and 93.8% (15/16) versus 56.3% (9/16) among non-cirrhotic treatment-naive and treatment-experienced patients, respectively]. No patient discontinued treatment because of an adverse event. The most common adverse events were anemia, increased blood bilirubin, and nasopharyngitis. CONCLUSIONS OBV/PTV/r + RBV for 16 weeks resulted in high SVR12 rates in non-cirrhotic Japanese patients infected with HCV GT2 who were treatment-naive or who had relapsed after an interferon-based therapy. Higher SVR12 rates were observed among patients with HCV GT2a infection versus those with GT2b infection. This regimen demonstrated a favorable safety profile. TRIAL REGISTRATION ClinicalTrials.gov identifier, NCT02023112. FUNDING AbbVie.
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Clinical Trial, Phase III |
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Sato K, Waguri S, Ohsawa Y, Nitatori T, Kon S, Kominami E, Watanabe T, Gotow T, Uchiyama Y. Immunocytochemical localization of lysosomal cysteine and aspartic proteinases, and ubiquitin in rat epidermis. ARCHIVES OF HISTOLOGY AND CYTOLOGY 1997; 60:275-287. [PMID: 9376175 DOI: 10.1679/aohc.60.275] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] [Imported: 10/24/2024]
Abstract
To analyze the degradation system in epidermal cells during their generation, differentiation, and cell death, immunocytochemical localization of lysosomal cysteine and aspartic proteinases, an endogenous cysteine proteinase inhibitor, cystatin beta, and ubiquitin were examined using rat sole skin. By confocal laser microscopy, granular immunodeposits for lysosomal proteinases were well demonstrated in epidermal cells; immunoreactivity for cathepsins B and C was prominent in the lower spinous and basal layers, while that for cathepsins L and D was intense in the upper spinous and granular layers, although immunoreactivity for cathepsin D was also detected in the lower epidermal layers. Immunoreactivity for cathepsin H was weakly detected only in the spinous layer, where there were some intensely immunopositive cells with processes which were also immunopositive for S-100 alpha, indicating that these cells were Langerhans cells. Diffuse immunoreactivity for cystatin beta was intense in the spinous and granular layers and weak in the basal layer. In addition, we also examined the localization of ubiquitin, which is a signal peptide for cytosolic proteolysis; clear-cut granular immunodeposits for ubiquitin were detected in spinous and granular cells, and some were co-localized with cathepsin B immunoreactivity. In the basal layer, mitotic cells were strongly immunopositive for ubiquitin. These results suggest that cysteine and aspartic proteinases are involved in the lysosomal system of the epidermis, showing different distributions in the epidermal layers depending on the enzymes examined. Moreover, ubiquitin may be associated with the cell cycle-dependent degradation in basal cells while it also participates in the non-lysosomal proteolysis and probably, lysosomal proteolysis in the spinous and granular cells.
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Sato K, Hashizume H, Yamazaki Y, Horiguchi N, Kakizaki S, Takagi H, Mori M. Response-guided peginterferon-alpha-2b plus ribavirin therapy for chronic hepatitis C patients with genotype 2 and high viral loads. Hepatol Res 2012; 42:854-863. [PMID: 22487210 DOI: 10.1111/j.1872-034x.2012.00997.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] [Imported: 10/24/2024]
Abstract
AIMS Optimization of the duration of peginterferon-α/ribavirin therapy in patients with hepatitis C virus (HCV) genotype 2 and high viral loads remains to be established. We sought to prospectively optimize the treatment duration based on their virological responses. METHODS Serum HCV RNA levels of less than 50 IU/mL at weeks 2 and 4, and of 50 IU/mL or more at week 4, were defined as a super-rapid virological response (SRVR), rapid virological response (RVR) and late virological response (LVR), respectively. Treatment for 12, 24 or 48 weeks was assigned to the patients with an SRVR, RVR or LVR, respectively. However, patients with an LVR who expressed a desire to receive the standard therapy duration were given the 24-week therapy. RESULTS The overall sustained virological response (SVR) rate was 78.1% (118/151). The SVR rate in the SRVR group was 93.8% (15/16), which was comparable to the 93.0% (66/71) SVR rate in the RVR group. In the LVR patients, the 48-week treatment slightly increased the SVR rate to 76.5% (13/17) compared with the 51.1% (24/47) SVR rate in LVR patients who underwent the standard 24-week treatment. The relapse rate in LVR patients was significantly decreased in patients treated for 48 weeks compared with patients treated for 24 weeks. Multivariate analysis identified the predictive factors for SVR as RVR, prior interferon therapy and total peginterferon-α-2b adherence in patients treated for 24 weeks. CONCLUSION Response-guided therapy may be effective and useful for optimization of the treatment duration.
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Sato K, Kobayashi T, Yamazaki Y, Takakusagi S, Horiguchi N, Kakizaki S, Kusano M, Yamada M. Spontaneous remission of hepatitis B virus reactivation during direct-acting antiviral agent-based therapy for chronic hepatitis C. Hepatol Res 2017; 47:1346-1353. [PMID: 28422376 DOI: 10.1111/hepr.12905] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/06/2017] [Accepted: 04/13/2017] [Indexed: 02/08/2023] [Imported: 10/24/2024]
Abstract
The administration of direct-acting antiviral agents (DAAs) to treat hepatitis C virus (HCV) infection has been reported to cause hepatitis B virus (HBV) reactivation. However, the actual conditions of HBV reactivation and the ideal timing of medical intervention have not been fully evaluated. We report the cases of two female patients dually infected with HBV and HCV. Both patients were inactive HBV carriers. Although the serum HCV RNA levels promptly decreased after the initiation of DAA-based therapy, the serum HBV DNA levels gradually increased during DAA-based therapy, with the peak serum HBV DNA levels observed at 16 weeks after the initiation of DAA-based therapy in both cases. Subsequently, we checked the serum HBV DNA levels closely every week several times. Fortunately, the serum HBV DNA levels gradually decreased without medical intervention. Neither case developed an alanine aminotransferase flare-up. The HCV genotypes were 2a and 1b, and the DAA-based therapies of Cases 1 and 2 were 12 weeks of sofosbuvir/ribavirin and ombitasvir/paritaprevir/ritonavir, respectively. The significance of our case reports is the demonstration of the existence of spontaneous remission of HBV reactivation that developed during DAA-based therapy, the avoidance of intervention of nucleot(s)ide analogs by frequent monitoring of serum HBV DNA levels, and development of HBV reactivation regardless of the viral genotype or class of DAA. In conclusion, the close monitoring of serum HBV DNA levels during and after DAA-based therapy is essential and medical intervention for HBV reactivation should be carefully considered on an individual basis.
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Case Reports |
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Sato K, Hosonuma K, Yamazaki Y, Kobayashi T, Takakusagi S, Horiguchi N, Kakizaki S, Kusano M, Ohnishi H, Okamoto H, Yamada M. Combination Therapy with Ombitasvir/Paritaprevir/Ritonavir for Dialysis Patients Infected with Hepatitis C Virus: A Prospective Multi-Institutional Study. TOHOKU J EXP MED 2017; 241:45-53. [PMID: 28090038 DOI: 10.1620/tjem.241.45] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] [Imported: 10/24/2024]
Abstract
Hepatitis C virus (HCV) infection is common in dialysis patients worldwide and nosocomial HCV spread within dialysis facilities continues to develop. Combination therapy with daclatasvir and asunaprevir (DCV/ASV) that has proven efficacy for dialysis patients infected with genotype 1b HCV (HCV/1b) has several concerns in Japan. The recently available combination therapy with ombitasvir, paritaprevir, and ritonavir (OBV/PTV/r) is not contraindicated in patients with chronic renal failure and has more safety profile and shorter treatment period than that with DCV/ASV. We evaluated the effects of combination therapy with OBV/PTV/r in four dialysis patients infected with HCV/1b, who were eligible for our study. On-treatment assessments included standard laboratory testing, serum HCV RNA and symptom-directed physical examinations. Three patients had a sustained virological response at 12 weeks after treatment, but one remaining patient had viral breakthrough. Notably, the patient with viral breakthrough had been coinfected with HCV/1b and HCV/2b; namely, HCV/2b with resistance-associated variations was not eradicated by the combination therapy. Among the three patients responsive to the combination therapy, one patient complained of appetite loss and itching, while in another patient the therapy was discontinued due to itching, exacerbation of wamble, and a falling tendency probably due to interaction with valsartan. These AEs were ameliorated or disappeared after the completion of the therapy. The significance of our study is persuasive virological evaluation associated to the combination therapy and reasonable interpretation of AEs. In conclusion, combination therapy with OBV/PTV/r may have promise as an efficacious therapy, but caution regarding AEs should be practiced.
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Case Reports |
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Sato K, Mori M. Evolving molecular mechanism-based strategies for control of hepatocellular carcinoma. Curr Med Chem 2011; 18:4375-4388. [PMID: 21861817 DOI: 10.2174/092986711797200462] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 07/08/2011] [Accepted: 07/10/2011] [Indexed: 01/03/2023] [Imported: 10/24/2024]
Abstract
Hepatocellular carcinoma (HCC) is a major cause of cancer mortality worldwide. Unresectable or metastatic HCC has a poor prognosis, and systemic cytotoxic chemotherapy has failed to show a substantial benefit for patients with HCC. However, there has been increasing interest in developing novel molecularly targeted agents in HCC due to the accumulation of knowledge of cell signaling and molecular carcinogenesis. Furthermore, some of these agents have proven to be efficacious in other traditionally challenging carcinomas, such as renal cell carcinoma. Recently, a phase III, randomized, placebo-controlled trial demonstrated that sorafenib, an oral multikinase inhibitor of the vascular endothelial growth factor receptor and Ras kinase, improves overall survival (OS) in patients with advanced HCC. This seminal study described the first agent to improve OS in HCC and began a new era of molecule-targeted cancer therapies. Currently, many novel molecularly targeted agents are under evaluation in clinical trials. In this review, we comprehensively summarize the molecular pathogenesis, targets, and signal transduction pathways involved in HCC. We also detail the current status of molecularly targeted agents that are under clinical development in advanced HCC, including the mechanisms of action of these agents.
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Review |
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Sato K, Yamazaki Y, Ohyama T, Kobayashi T, Horiguchi N, Kakizaki S, Kusano M, Yamada M. Combination therapy with daclatasvir and asunaprevir for dialysis patients infected with hepatitis C virus. World J Clin Cases 2016; 4:88-93. [PMID: 26989674 PMCID: PMC4792170 DOI: 10.12998/wjcc.v4.i3.88] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 01/12/2016] [Accepted: 01/29/2016] [Indexed: 02/05/2023] [Imported: 10/16/2024] Open
Abstract
The standard antiviral therapy for dialysis patients infected with hepatitis C virus (HCV) is (pegylated) interferon monotherapy, but its efficacy is insufficient. Oral direct-acting antiviral agents (DAAs) have recently been developed for chronic hepatitis C patients. However, some DAAs have contraindications for chronic renal failure (CRF). Daclatasvir and asunaprevir are metabolized largely in the liver and are not contraindicated in CRF. Combination therapy with daclatasvir and asunaprevir was used for 4 dialysis patients infected with genotype 1b HCV. One patient had viral breakthrough, and the 3 others had sustained virological response 12. One patient was admitted for heart failure and percutaneous coronary intervention due to concomitant ischemic disease. Heart failure was unlikely to be caused by the combination therapy, as it was probably due to water overload. The patient continued to receive the combination therapy after the remission of the heart failure. The combination therapy was well tolerated in the other patients.
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Case Report |
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Sato K, Naganuma A, Nagashima T, Hoshino T, Uehara D, Arai Y, Horiuchi K, Yuasa K, Takayama H, Arai H, Hatanaka T, Ohyama T, Tahara H, Sohara N, Kobayashi T, Horiguchi N, Yamazaki Y, Kakizaki S, Kusano M, Yamada M, Murase T, Nakamura T. Elevated serum uric acid level was a notable adverse event during combination therapy with sofosbuvir and ribavirin. Hepatol Res 2018; 48:E347-E353. [PMID: 28834004 DOI: 10.1111/hepr.12971] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 05/10/2017] [Accepted: 08/14/2017] [Indexed: 02/08/2023] [Imported: 10/24/2024]
Abstract
AIM Combination therapy with sofosbuvir and ribavirin (SOF/RBV) has been recently available for chronic hepatitis C patients with genotype 2 (CHG2) in Japan. The domestic phase III clinical trial showed a high antiviral effect with a relatively safe adverse event (AE) profile. Our aim was to report an important AE detected during treatment. METHODS A prospective multi-institutional study of 12-week combination therapy with SOF/RBV for CHG2 was carried out to evaluate efficacy and safety. RESULTS The eligible subjects included 142 patients. Out of 50 assessable patients, 16% of the patients were diagnosed with hyperuricemia. The proportions of subjects with grade 1, grade 3, and grade 4 hyperuricemia were 12, 2, and 2%, respectively. Serum uric acid (UA) levels at week 1 of the therapy (W1) were numerically the highest during therapy in patients with hyperuricemia, and the ratio of W1/baseline serum UA levels was significantly higher than that of post-treatment week 4 or 8/baseline serum UA levels in assessable patients. Serum UA levels at W1 were significantly correlated with body mass index. The difference between serum UA levels at W1 and baseline serum UA levels was significantly correlated with the difference between serum creatinine levels at W1 and baseline serum creatinine levels. CONCLUSIONS Elevated serum UA level was a notable AE associated with SOF/RBV therapy for CHG2. However, because of the small number of subjects, the exact frequency of AEs should be re-evaluated with larger cohorts. We need to remember that elevated serum UA level might develop during the therapy, especially at W1.
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Sato K, Sato N, Shimizu H, Tsutiya T, Takahashi H, Kakizaki S, Takayama H, Takagi H, Mori M. Faropenem enhances superoxide anion production by human neutrophils in vitro. J Antimicrob Chemother 1999; 44:337-341. [PMID: 10511400 DOI: 10.1093/jac/44.3.337] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] [Imported: 10/24/2024] Open
Abstract
Neutrophils are important cellular components in the defence against infections and many studies in vitro have shown that some antibiotics affect neutrophil function. We examined the effect of faropenem, a new oral penem antibiotic on neutrophil killing function by determining the generation of superoxide anion in vitro. The production of superoxide anion was measured by chemiluminescence amplified by a Cypridina luciferin analogue in the presence of N-formyl-Met-Leu-Phe (fMLP). Faropenem significantly enhanced chemiluminescence in a dose-dependent manner. The effect of faropenem was maximal at 5 min of incubation time and continued for at least 30 min. The effect of faropenem was also observed when neutrophils were stimulated by a calcium ionophore (ionomycin), while the effect of faropenem did not change in the presence of 12-O-tetra-decanoylphorbolmyristate acetate. Cytosol Ca2+ concentration ([Ca2+]i) monitored with Fura-2 increased in response to fMLP, however, faropenem did not influence the response of [Ca2+]i to fMLP. Our results suggest that faropenem enhanced the generation of superoxide anion by neutrophils, probably at the site where cytosol Ca2+ regulates NADPH oxidase. Faropenem might be potentially advantageous in the treatment of infections because a synergic interaction of antibodies and cytocidal neutrophils is necessary for the early eradication of the pathogenic bacteria.
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Sato K, Uraoka T. Challenge to overcome: Nonstructural protein 5A-P32 deletion in direct-acting antiviral-based therapy for hepatitis C virus. World J Gastroenterol 2018; 24:4304-4310. [PMID: 30344416 PMCID: PMC6189846 DOI: 10.3748/wjg.v24.i38.4304] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/02/2018] [Accepted: 08/24/2018] [Indexed: 02/06/2023] [Imported: 10/16/2024] Open
Abstract
Interferon (IFN)-based therapy for hepatitis C virus (HCV) infection has recently been replaced by IFN-free direct-acting antiviral (DAA)-based therapy, which has been established as a 1st line therapy with high efficacy and tolerability due to its reasonable safety profile. Resistance-associated substitutions (RASs) have been a weakness of DAA-based therapy. For example, combination therapy with daclatasvir and asunaprevir (DCV/ASV) is less effective for HCV genotype 1-infected patients with Y93H as a nonstructural protein 5A RAS. However, the problem regarding RASs has been gradually overcome with the advent of recently developed DAAs, such as sofosbuvir-based regimens or combination therapy with glecaprevir and pibrentasvir. Despite the high efficiency of DAA-based therapy, some cases fail to achieve viral eradication. P32 deletion, an NS5A RAS, has been gradually noticed in patients with DCV/ASV failure. P32 deletion has been sporadically reported and the prevalence of this RAS has been considered to be low in patients with DCV/ASV failure. Thus, the picture of P32 deletion has not been fully evaluated. Importantly, currently-commercialized DAA-based combination therapy was not likely to be effective for patients with P32 deletion. Exploring and overcoming this RAS is essential for antiviral therapy for chronic hepatitis C.
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Editorial |
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Sato K, Hayashi M, Utsugi M, Ishizuka T, Takagi H, Mori M. Acute pancreatitis in a patient treated with micafungin. Clin Ther 2007; 29:1468-1473. [PMID: 17825698 DOI: 10.1016/j.clinthera.2007.07.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2007] [Indexed: 11/16/2022] [Imported: 10/24/2024]
Abstract
CASE SUMMARY A 73-year-old man (height, 158.2 cm; weight, 49.8 kg) presented with upper abdominal tenderness after 3 weeks of treatment with 150 mg/d of micafungin (3 mg/kg . d) (Mycamine, Astellas Pharma US Inc., Deerfield, Illinois) intravenously for pulmonary aspergillosis accompanied by [DOSAGE ERROR CORRECTED] pulmonary Mycobacterium avium complex (MAC) infection. Pulmonary aspergillosis was noninvasively diagnosed by a fungus lump in a cavity in the right upper lung field with a high value of 1,3-beta-D-glucan and a positive result for aspergillosis antigen. The patient had a medical history of gastrectomy due to gastric cancer and idiopathic thrombocytopenic purpura (ITP). He had been prescribed 800 mg/d of clarithromycin, 400 mg/dL of rifampicin, and 750 mg/d of ethambutol hydrochloride for pulmonary MAC infection for 2 years and 5 mg/d of prednisolone for ITP for 7 years. No traditional or homeopathic medicine had been received/administered. Laboratory tests at the onset of abdominal pain revealed a white blood cell count of 4300/microL with 51% neutrophils. There was no eosinophilia. Platelet count was 15,100/muL, with normal coagulation. Immunoglobulin G and immunoglobulin M were 1720 and 154 mg/dL, respectively. The patient had no history of allergy, biliary tract disease, hyperlipidemia, or hypercalcemia. He did not report alcohol use. The laboratory findings, magnetic resonance imaging, and upper abdominal tenderness were consistent with acute pancreatitis. After cessation of all drugs, his symptoms improved with bowel rest and parenteral nutrition. His laboratory measurements normalized thereafter. All drugs, except micafungin, were readministered for pulmonary MAC infection and ITP, and itraconazole was administered for pulmonary aspergillosis after the recovery from pancreatitis. During 16 months of follow-up, the pancreatitis did not recur. DISCUSSION We performed a literature search of all available English-language articles published on MEDLINE between January 1966 and January 2007 using the key terms micafungin (text and indexed terms) and pancreatitis (text and indexed terms). Based on the search of MEDLINE, there have been no reports of acute pancreatitis associated with micafungin. The Naranjo adverse drug reaction (ADR) probability scale was used to assess the probability of micafungin-associated acute pancreatitis. A score of 6 was obtained, indicating a probable ADR from micafungin treatment. CONCLUSION We report a case of acute pancreatitis probably associated with micafungin use in an elderly patient.
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Case Reports |
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Sato K, Sakaguchi A, Sato M. REI/SH3BP5 protein family: New GEFs for Rab11. Cell Cycle 2016; 15:767-769. [PMID: 26745340 PMCID: PMC4845920 DOI: 10.1080/15384101.2015.1137710] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 12/29/2015] [Indexed: 10/22/2022] [Imported: 10/24/2024] Open
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editorial |
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Sato K, Sato N, Mori M. Isotonic ethanol inhibits the generation of superoxide anion in neutrophils by inducing cell expansion. Life Sci 1998; 63:1329-1337. [PMID: 9768870 DOI: 10.1016/s0024-3205(98)00396-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] [Imported: 10/24/2024]
Abstract
The effects of ethanol on the production of oxygen-derived free radicals by neutrophils are controversial. Osmolarity-mediated alteration of cell volume appears to be an important mechanism for regulating neutrophil activity. We investigated in neutrophils from healthy volunteers the effect of isotonic/hypertonic ethanol on both chemiluminescence amplified by a Cypridina luciferin analog in response to N-formyl-Met-Lue-Phe and cell volume measured with a Coulter counter. Both isotonic and hypertonic ethanol significantly decreased chemiluminescence in a dose-dependent manner. Isotonic ethanol produced a greater magnitude of inhibition than hypertonic ethanol (P<0.01). Another permeable molecule, urea, and hypotonic solution had the same effects on chemiluminescence. Isotonic and hypertonic ethanol caused a prompt cell expansion and shrinking, respectively. On the other hand, isotonic sucrose, an impermeable molecule, was ineffective in both chemiluminescence and cell volume changes. These data suggest that isotonic ethanol inhibits the superoxide anion production by inducing cell expansion probably due to increased intracellular osmotic pressure caused by rapid ethanol permeation through the plasmalemma. This impaired neutrophil function may, in some part, contribute to the susceptibility to infection in alcoholics.
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Sato K, Yamada E, Uehara Y, Takagi H, Mori M. Possible role for human leukocyte antigen haplotype in rofecoxib-associated acute pancreatitis and cholestatic hepatitis. Clin Pharmacol Ther 2006; 80:554-555. [PMID: 17112814 DOI: 10.1016/j.clpt.2006.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Accepted: 08/17/2006] [Indexed: 11/29/2022] [Imported: 10/24/2024]
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Case Reports |
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Sato K, Yamazaki Y, Uraoka T. Strategy for the control of drug-induced liver injury due to investigational treatments/drugs for COVID-19. World J Gastroenterol 2021; 27:8370-8373. [PMID: 35068875 PMCID: PMC8717018 DOI: 10.3748/wjg.v27.i48.8370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 11/18/2021] [Accepted: 11/10/2021] [Indexed: 02/06/2023] [Imported: 10/16/2024] Open
Abstract
Investigational treatments/drugs for coronavirus disease 2019 (COVID-19) have been applied, with repurposed or newly developed drugs, and their effectiveness has been evaluated. Some of these drugs may be hepatotoxic, and each monotherapy or combination therapy may increase the risk of drug-induced liver injury (DILI). We should aim to control dysregulation of liver function, as well as the progression of COVID-19, as much as possible. We discussed the potential risks of investigational treatments/drugs and promising drugs for both COVID-19 and DILI due to investigational treatments/drugs.
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Letter to the Editor |
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Sato K, Takagi H, Fukusato T, Kanda D, Mori M. Hepatocellular carcinoma in primary biliary cirrhosis: case reports and review of the literature. Histopathology 2002; 40:490-492. [PMID: 12010375 DOI: 10.1046/j.1365-2559.2002.t01-5-01390.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] [Imported: 10/24/2024]
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Case Reports |
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Sato K, Amanuma M, Fukusato T, Sohara N, Kakizaki S, Takagi H, Mori M. Diffuse hepatic vascular malformations with right aortic arch. J Hepatol 2005; 43:1094-1095. [PMID: 16233934 DOI: 10.1016/j.jhep.2005.08.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Revised: 07/19/2005] [Accepted: 08/17/2005] [Indexed: 12/04/2022] [Imported: 10/24/2024]
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Case Reports |
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