Ryota Tanaka

Kumamoto University, Kumamoto, Kumamoto Prefecture, Japan

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Publications (6)37.59 Total impact

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    ABSTRACT: Overdoses of acetaminophen (APAP) are a major cause of acute liver failure. N-acetylcysteine (NAC) is the standard therapy for the patients with such an overdose because oxidative stress plays an important role in the pathogenesis of APAP-induced hepatitis. However, NAC is not sufficiently efficacious. We previously developed a recombinant human serum albumin (HSA)-thioredoxin 1 (Trx) fusion protein (HSA-Trx), designed to overcome the unfavorable pharmacokinetic and short pharmacological properties of Trx, an endogenous protein with anti-oxidative and anti-inflammatory properties. In this study, we investigated the therapeutic impact of HSA-Trx in mice with APAP-induced hepatitis. The systemic administration of HSA-Trx significantly improved the survival rate of mice treated with a lethal dose of APAP compared with saline. HSA-Trx strongly attenuated plasma transaminases in APAP-induced hepatitis mice compared with HSA or Trx, components of the fusion protein. HSA-Trx also markedly caused a diminution in the histopathological features of hepatic injuries and the number of apoptosis-positive hepatic cells. In addition, an evaluation of oxidative stress markers and plasma cytokine and chemokine levels clearly showed that HSA-Trx significantly improved the breakdown of hepatic redox conditions and inflammation caused by the APAP treatment. HSA-Trx also significantly decreased oxidative and nitrosative/nitrative stress induced by SIN-1 in vitro. Finally, HSA-Trx, but not the NAC treatment at 4 hours after APAP injection, significantly inhibited the elevation in plasma transaminases levels. In conclusion, the findings suggest that HSA-Trx has considerable potential for use as a novel therapeutic agent for APAP-induced hepatitis, due to its long-lasting anti-oxidative and anti-inflammatory effects.
    Molecular Pharmaceutics 02/2014; · 4.57 Impact Factor
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    ABSTRACT: Carbon monoxide (CO) has potent anti-inflammatory and anti-oxidant effects. We report herein on the preparation of a nanotechnology-based CO donor, CO-bound hemoglobin-vesicles (CO-HbV). We hypothesized that CO-HbV could have a therapeutic effect on idiopathic pulmonary fibrosis (IPF), an incurable lung fibrosis, that is thought to involve inflammation and the production of reactive oxygen species (ROS). Pulmonary fibril formation and respiratory function were quantitatively evaluated by measuring hydroxyproline levels and forced vital capacity, respectively, using a bleomycin-induced pulmonary fibrosis mice model. CO-HbV suppressed the progression of pulmonary fibril formation and improved respiratory function compared to saline and HbV. The suppressive effect of CO-HbV on pulmonary fibrosis can be attributed to a decrease in ROS generation by inflammatory cells, NADPH oxidase 4 and the production of inflammatory cells, cytokines and transforming growth factor-β in the lung. This is the first demonstration of the inhibitory effect of CO-HbV on the progression of pulmonary fibrosis via the anti-oxidative and anti-inflammatory effects of CO in the bleomycin-induced pulmonary fibrosis mice model. CO-HbV has the potential for use in the treatment of, not only IPF, but also a variety of other ROS and inflammation-related disorders.
    Biomaterials 01/2014; 35(24):6553–6562. · 8.31 Impact Factor
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    ABSTRACT: A strategy for preventing cisplatin nephrotoxicity due to enhanced oxidative stress and inflammatory response is highly desirable. Thioredoxin-1 (Trx), an endogenous redox-active protein, has a short retention time in the blood. A long acting form of Trx, human serum albumin-Trx (HSA-Trx), was produced by recombinant HSA fusion and its effectiveness in preventing cisplatin nephrotoxicity was examined. HSA-Trx was prepared in Pichia expression system. Cisplatin-induced nephropathy model mouse was established by a single administration of cisplatin. Compared to saline, Trx or N-acetylcysteine, an intravenous administration of HSA-Trx attenuated the cisplatin-induced elevation in serum creatinine, blood urea nitrogen and urinary N-acetyl-β-D-glucosaminidase along with the decrease in creatinine clearance. HSA-Trx caused a substantial reduction in the histological features of renal tubular injuries and the apoptosis-positive tubular cells. Changes in superoxide, 8-OHdG, glutathione and nitrothyrosine levels indicated that HSA-Trx significantly suppressed renal oxidative stress. HSA-Trx also suppressed the elevation of TNF-α, IL-1β and IL-6. Administered fluorescein isothiocyanate-labeled HSA-Trx was found partially localized in the proximal tubular cells whereas majority remained in the blood circulation. Specific cellular uptake and the scavenging of intracellular reactive oxygen species by HSA-Trx were observed in HK-2 cells. HSA-Trx could be a novel and effective approach for preventing cisplatin nephrotoxicity due to its prolonged anti-oxidative and anti-inflammatory action not only in extracellular compartment but also inside the proximal tubular cell. General significance We report the renoprotective effect of HSA-Trx against cisplatin nephrotoxicity. This work would enhance developing therapeutics against acute kidney injuries including cisplatin nephrotoxicity.
    Biochimica et Biophysica Acta 12/2013; · 4.66 Impact Factor
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    ABSTRACT: Idiopathic pulmonary fibrosis (IPF) is thought to involve inflammatory cells and reactive oxygen species (ROS), such as superoxide anion radical (O(2)(·-)). There is currently no effective treatment for IPF. We previously developed a human serum albumin (HSA)-thioredoxin 1 (Trx) fusion protein (HSA-Trx), designed to overcome the unfavorable pharmacokinetic and short pharmacological properties of Trx, an anti-oxidative and anti-inflammatory protein. In this study, we examined the therapeutic effect of HSA-Trx on an IPF animal model of bleomycin (BLM)-induced pulmonary fibrosis. A pharmacokinetic study of HSA-Trx or Trx in BLM mice showed that the plasma retention and lung distribution of Trx was markedly improved by fusion with HSA. A weekly intravenous administration of HSA-Trx, but not Trx, ameliorated BLM-induced fibrosis as evidenced by a histopathological analysis and pulmonary hydroxyproline levels. HSA-Trx suppressed active-TGF-β levels in the lung and inhibited the increase of inflammatory cells in BALF, pulmonary inflammatory cytokines and oxidative stress markers. An in vitro EPR experiment using PMA-stimulated neutrophils confirmed the O(2)(·-) scavenging ability of HSA-Trx. Furthermore, post-treatment of HSA-Trx had a suppressive effect against BLM-induced fibrosis. These results suggest that HSA-Trx has potential as a novel therapeutic agent for IPF, due to its long-acting anti-oxidative and anti-inflammatory modulation effects.
    Journal of Pharmacology and Experimental Therapeutics 02/2013; · 3.89 Impact Factor
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    ABSTRACT: Contrast-induced nephropathy (CIN), caused by a combination of the direct tubular toxicity of contrast media, a reduction in medullary blood flow, and the generation of reactive oxygen species, is a serious clinical problem. A need exists for effective strategies for its prevention. Thioredoxin-1 (Trx) is a low-molecular-weight endogenous redox-active protein with a short half-life in the blood due to renal excretion. We produced a long-acting form of Trx as a recombinant human albumin-Trx fusion protein (HSA-Trx) and examined its effectiveness in preventing renal injury in a rat model of ioversol-induced CIN. Compared with saline, a mixture of HSA and Trx, or Trx alone, intravenous HSA-Trx pretreatment significantly attenuated elevations in serum creatinine, blood urea nitrogen, and urinary N-acetyl-β-D-glucosaminidase along with the decrease in creatinine clearance. HSA-Trx also caused a substantial reduction in the histological features of renal tubular injuries and in the number of apoptosis-positive tubular cells. Changes in the markers 8-hydroxy deoxyguanosine and malondialdehyde indicated that HSA-Trx significantly suppressed renal oxidative stress. In HK-2 cells, HSA-Trx decreased the level of reactive oxygen species induced by hydrogen peroxide, and subsequently improved cell viability. Thus, our results suggest that due to its long-acting properties, HSA-Trx has the potential to effectively prevent CIN.Kidney International advance online publication, 2 January 2013; doi:10.1038/ki.2012.429.
    Kidney International 01/2013; · 8.52 Impact Factor
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    ABSTRACT: Thioredoxin (Trx) is a redox-active protein with anti-inflammatory effects but with a short half life of 1 h. Genetic fusion of Trx to human serum albumin (HSA) extended its half life without causing significant loss of its biological activities. HSA-Trx caused a decrease in the number of cells in brochoalveolar lavage fluid, the wet/dry ratio and the inflammation at the respiratory tract of the ovalbumin (OVA) induced lung injury model mouse. Three intraperitoneal doses of Trx alone produced the same extent of suppression of those three detrimental effects of OVA as one intravenous dose of HSA-Trx. Inhibition experiments confirmed that reactive oxygen species (ROS) and reactive nitrogen species (RNS) involved in the progression of the injury. HSA-Trx inhibited the production of ROS as confirmed in the EPR experiment, but lung tissue staining suggested that induced nitrogen oxide synthase (iNOS) was not suppressed by the fusion protein. Instead, the production of nitrotyrosine, 8-nitro-cGMP, and 8-hydroxy-2'-deoxyguanosine downstream to the iNOS has been inhibited. This suggested that HSA-Trx produced lung protection effect via different mechanisms from Trx alone. HSA-Trx retains the biological properties of Trx thus has great potential in treating oxidative stress related diseases.
    Journal of Controlled Release 05/2011; 154(2):189-95. · 7.63 Impact Factor