Renoprotective effect of long acting thioredoxin by modulating oxidative stress and macrophage migration inhibitory factor against rhabdomyolysis-associated acute kidney injury.

Rhabdomyolysis-associated acute kidney injury (AKI) is a serious life-threatening condition. As such, more effective strategies are needed for its prevention. Thioredoxin-1 (Trx), a redox-active and macrophage migration inhibitory factor (MIF) modulating protein, has a short retention time in the blood. We examined the renoprotective effect of long acting Trx that was genetically fused with human serum albumin (HSA-Trx) against glycerol-induced AKI. An intravenous HSA-Trx pre-treatment attenuated the glycerol-induced decline in renal function, compared to a PBS, HSA or Trx alone. HSA-Trx caused a reduction in the tubular injuries and in the number of apoptosis-positive tubular cells. Renal superoxide, 8-hydroxy deoxyguanosine, nitrotyrosine and the plasma Cys34-cysteinylated albumin were clearly suppressed by the HSA-Trx treatment. Prior to decreasing TNF-α and IL-6, HSA-Trx suppressed an increase of plasma MIF level. In LLC-PK1 cells, HSA-Trx decreased the level of reactive oxygen species and lactate dehydrogenase release induced by myoglobin. HSA-Trx treatment resulted in a threefold increase in the survival of lethal glycerol-treated mice. The post-administration of HSA-Trx at 1 and 3 hr after glycerol injection exerted a significant renoprotective effect. These results suggest HSA-Trx has potential for use in the treatment of rhabdomyolysis-associated AKI via its extended effects of modulating oxidative stress and MIF.

S-Nitrosated human serum albumin dimer as novel nano-EPR enhancer applied to macromolecular anti-tumor drugs such as micelles and liposomes.

The enhanced permeability and retention (EPR) effect is a unique phenomenon of solid tumors, and it can serve as a basis for the development of macromolecular anticancer therapy. We have previously found that recombinant human serum albumin dimer, and especially its S-nitrosated form (SNO-HSA-Dimer), is an enhancer of the EPR effect. In this study, we investigated the influence of SNO-HSA-Dimer on the anti-tumor effect of two types of macromolecular anti-tumor drugs, namely N-(2-hydroxypropyl)methacrylamide polymer conjugated with zinc protoporphyrin, which forms micelles and can be used for fluorescence studies. The other was PEGylated liposomal doxorubicin (Doxil), a typical example of a stealth liposome approved for medical usage. In mice having C26 tumors with highly permeable vasculature, SNO-HSA-Dimer increases tumor accumulation of the drugs by a factor 3-4 and thereby their anti-tumor effects. Experiments with Evans blue revealed increased EPR effect in all parts of the tumor. Furthermore, SNO-HSA-Dimer improves the anti-metastatic effects of Doxil and reduces its minor uptake in non-tumorous organs such as liver and kidney. Tumor accumulation of Doxil in B16 tumors, which are characterized by a low permeable vasculature, increased even more (6-fold) in the presence of SNO-HSA-Dimer, and the improved accumulation lead to decreased tumor volume and increased survival of the animals. The administration of SNO-HSA-Dimer itself is safe, because it has no effect on blood pressure, heart rate or on several biochemical parameters. The present findings indicate that SNO-HSA-Dimer is promising for enhancing the EPR effect and consequently the specific, therapeutic effects of macromolecular anticancer drugs.

Albumin fusion prolongs the antioxidant and anti-inflammatory activities of thioredoxin in mice with acetaminophen-induced hepatitis.

Overdoses of acetaminophen (APAP) are a major cause of acute liver failure. N-Acetylcysteine (NAC) is the standard therapy for 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 antioxidative 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 h after APAP injection, significantly inhibited the elevation in plasma transaminase 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 antioxidative and anti-inflammatory effects.

Albumin fusion renders thioredoxin an effective anti-oxidative and anti-inflammatory agent for preventing cisplatin-induced nephrotoxicity.

BACKGROUND: 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. METHODS: HSA-Trx was prepared in Pichia expression system. Cisplatin-induced nephropathy mouse model was established by a single administration of cisplatin. RESULTS: 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-ß-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 nitrotyrosine levels indicated that HSA-Trx significantly suppressed renal oxidative stress. HSA-Trx also suppressed the elevation of TNF-α, IL-1ß 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. CONCLUSION: 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.

Long-acting human serum albumin-thioredoxin fusion protein suppresses bleomycin-induced pulmonary fibrosis progression.

Idiopathic pulmonary fibrosis (IPF) is thought to involve inflammatory cells and reactive oxygen species (ROS), such as superoxide anion radical (O2(·-)). There is currently no effective treatment of 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 antioxidative 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 Trxc 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-transforming growth factor (TGF)-ß levels in the lung and inhibited the increase of inflammatory cells in bronchoalveolar lavage fluid, pulmonary inflammatory cytokines, and oxidative stress markers. An in vitro EPR experiment using phosphate-buffered saline-stimulated neutrophils confirmed the O2(·-) 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, because of its long-acting antioxidative and anti-inflammatory modulation effects.

A human serum albumin-thioredoxin fusion protein prevents experimental contrast-induced nephropathy.

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-ß-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.

α(1)-Acid glycoprotein up-regulates CD163 via TLR4/CD14 protein pathway: possible protection against hemolysis-induced oxidative stress.

CD163, a scavenger receptor that is expressed at high levels in the monocyte-macrophage system, is a critical factor for the efficient extracellular hemoglobin (Hb) clearance during hemolysis. Because of the enormous detrimental effect of liberated Hb on our body by its ability to induce pro-inflammatory signals and tissue damage, an understanding of the molecular mechanisms associated with CD163 expression during the acute phase response is a central issue. We report here that α(1)-acid glycoprotein (AGP), an acute phase protein, the serum concentration of which is elevated under various inflammatory conditions, including hemolysis, up-regulates CD163 expression in both macrophage-like differentiated THP-1 (dTHP-1) cells and peripheral blood mononuclear cells in a time- and concentration-dependent manner. Moreover, the subsequent induction of Hb uptake was also observed in AGP-treated dTHP-1 cells. Among representative acute phase proteins such as AGP, α(1)-antitrypsin, C-reactive protein, and haptoglobin, only AGP increased CD163 expression, suggesting that AGP plays a specific role in the regulation of CD163. Consistently, the physiological concentrations of AGP induced CD163, and the subsequent induction of Hb uptake as well as the reduction of oxidative stress in plasma were observed in phenylhydrazine-induced hemolytic model mice, confirming the in vivo role of AGP. Finally, AGP signaling through the toll-like receptor-4 (TLR4) and CD14, the common innate immune receptor complex that normally recognizes bacterial components, was identified as a crucial stimulus that induces the autocrine regulatory loops of IL-6 and/or IL-10 via NF-κB, p38, and JNK pathways, which leads to an enhancement in CD163 expression. These findings provide possible insights into how AGP exerts anti-inflammatory properties against hemolysis-induced oxidative stress.

Production of immunoaffinity membranes for direct analysis of antigen after antibody separation and blotting under non-denaturing conditions.

Membrane-immobilized anti-transferrin antibody, which was produced after antibody was separated using non-denaturing two-dimensional electrophoresis (2DE), was transferred to a polyvinylidene difluoride (PVDF) membrane and was stained by direct blue 71. The antigen, transferrin, specifically bound to the membrane-immobilized antibody and was eluted only after rinsing the membrane with glutamic acid or aspartic acid solution. The antigen was analyzed directly by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) when the membrane was incubated with human plasma after the removal of human serum albumin using polyethylene glycol. The transferrin extracted by glutamic acid or aspartic acid solution retained the binding of Fe3+ in the presence of the carbonate anion. We found that immunoaffinity membranes can be useful for simple and rapid removal and extraction of intact proteins after antibody separation and blotting under non-denaturing conditions.