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Ishima Y.,Kumamoto University | Fang J.,Sojo University | Maeda H.,Sojo University | Kragh-Hansen U.,University of Aarhus | And 3 more authors.
Bioconjugate Chemistry | Year: 2012

Macromolecules have been developed as carriers of low-molecular-weight drugs in drug delivery systems (DDS) to improve their pharmacokinetic profile or to promote their uptake in tumor tissue via enhanced permeability and retention (EPR) effects. In the present study, recombinant human serum albumin dimer (AL-Dimer), which was designed by linking two human serum albumin (HSA) molecules with the amino acid linker (GGGGS) 2, significantly accumulated in tumor tissue even more than HSA Monomer (AL-Monomer) and appearing to have good retention in circulating blood in murine colon 26 (C26) tumor-bearing mice. Moreover, we developed S-nitrosated AL-Dimer (SNO-AL-Dimer) as a novel DDS compound containing AL-Dimer as a carrier, and nitric oxide (NO) as (i) an anticancer therapeutic drug/cell death inducer and (ii) an enhancer of the EPR effect. We observed that SNO-AL-Dimer treatment induced apoptosis of C26 tumor cells in vitro, depending on the concentration of NO. In in vivo experiments, SNO-AL-Dimer was found to specifically deliver large amounts of cytotoxic NO into tumor tissue but not into normal organs in C26 tumor-bearing mice as compared with control (untreated tumor-bearing mice) and SNO-AL-Monomer-treated mice. Intriguingly, S-nitrosation improved the uptake of AL-Dimer in tumor tissue through augmenting the EPR effect. These data suggest that SNO-AL-Dimer behaves not only as an anticancer therapeutic drug, but also as a potentiator of the EPR effect. Therefore, SNO-AL-Dimer would be a very appealing carrier for utilization of the EPR effect in future development of cancer therapeutics. © 2012 American Chemical Society.

Anraku M.,Sojo University | Shintomo R.,Kumamoto University | Taguchi K.,Sojo University | Kragh-Hansen U.,University of Aarhus | And 3 more authors.
Life Sciences | Year: 2015

Aims: To determine molecular information about the antioxidant properties of human serum albumin, which is an important extracellular antioxidant. To obtain this information, we studied this function of the protein by using H2O2 as the representative reactive oxygen species and two recombinant mutants and ten genetic variants with single-residue mutations. Main methods: The antioxidant capabilities of the isoforms were registered as their ability to diminish the H2O2-induced conversion of dihydrorhodamine 123 to rhodamine 123, which can emit fluorescence at 536 nm. Structural properties were examined by circular dichroism and SDS-PAGE. Key findings: Cysteine residues are important for the antioxidant function, but their effect depends on their position in the protein, with Cys410 > Cys34 ∼ Cys169 (when not involved in forming a disulfide bond). Likewise, the substitution of a glutamic acid at position 122 or 541, but not at 240 or 560, improves the antioxidant effect, perhaps by making the methionine residues in their vicinity, Met123 and Met548, respectively, more accessible for the oxidant. A lysine at position 505, but not at 82 or 570, decreases the oxidative effect. Finally, the mutations D269G and K276N had no effect. In certain cases, albumin acts as a sacrificial antioxidant, as in the case of the mutants C34S and, in particular, R410C and E505K. Significance: The information gained is of protein chemical relevance, but it may also be helpful in understanding the function of proteins that act as antioxidants in biological systems subjected to oxidative stress in conditions such as inflammation and aging. © 2015 Elsevier Inc. All rights reserved.

Ishima Y.,Kumamoto University | Shinagawa T.,Kumamoto University | Yoneshige S.,Kumamoto University | Kragh-Hansen U.,University of Aarhus | And 7 more authors.
Nitric Oxide - Biology and Chemistry | Year: 2013

S-Nitrosated human serum albumin (SNO-HSA) is useful in preventing liver ischemia/reperfusion injury, and SNO-HSA should thus be able to prevent cell injury during liver transplantation. However, the potential protective effect of SNO-HSA on a combination of cold and warm ischemia, which is obligatory when performing liver transplantation, has not been examined. Therefore, we evaluated the protective effect of SNO-HSA added to University of Wisconsin (UW) solution during cold or/and warm ischemia in situ and in vitro. First, we observed that apoptotic and necrotic cell death were increased during cold and warm ischemia, respectively. SNO-HSA, which possesses anti-apoptosis activity at low NO concentrations, can inhibit cold ischemia injury both in situ and in vitro. In contrast, SNO-HSA had no significant effect on warm liver ischemia injury which, however, can be reduced by UW solution. We also demonstrated that the cellular uptake of NO from SNO-HSA can occur during cold ischemia resulting in induction of heme oxygenase-1 within 3 h of cold ischemia. Our results indicate that treatment with SNO-HSA or UW solution alone is not sufficient to inhibit liver injury during a period of both cold and warm ischemia. However, a combination of SNO-HSA and UW solution can be used to prevent the two types of ischemia. SNO-HSA-added UW solution could be very useful in transplantation, because the previously imposed constraints on preservation time can be removed. This is a great advantage in a situation as the present one with increased utilization of scarce donor organs for more recipients. © 2013 Elsevier Inc. All rights reserved.

Watanabe K.,Kumamoto University | Ishima Y.,Kumamoto University | Akaike T.,Kumamoto University | Sawa T.,Kumamoto University | And 10 more authors.
FASEB Journal | Year: 2013

Treating infections with exogenous NO, which shows broad-spectrum antimicrobial activity, appears to be effective. Similar to NO biosynthesis, biosynthesis of α-1-acid glycoprotein variant A (AGPa), with a reduced cysteine (Cys149), increases markedly during inflammation and infection. We hypothesized that AGPa is an S-nitrosation target in acute-phase proteins. This study aimed to determine whether S-nitrosated AGPa (SNO-AGPa) may be the first compound of this novel antibacterial class against multidrug-resistant bacteria. AGPa was incubated with RAW264.7 cells activated by lipopolysaccharide and interferon-γ. The antimicrobial effects of SNO-AGPa were determined by measuring the turbidity of the bacterial suspensions in vitro and survival in a murine sepsis model in vivo, respectively. Results indicated that endogenous NO generated by activated RAW264.7 cells caused S-nitrosation of AGPa at Cys149. SNO-AGPa strongly inhibited growth of gram-positive, gram-negative, and multidrug-resistant bacteria and was an extremely potent bacteriostatic compound (IC50: 10-9 to 10-6 M). The antibacterial mechanism of SNO-AGPa involves S-transnitrosation from SNO-AGPa to bacterial cells. Treatment with SNO-AGPa, but not with AGPa, markedly reduced bacterial counts in blood and liver in a mouse sepsis model. The sialyl residues of AGPa seem to suppress the antibacterial activity, since SNO-asialo AGPa was more potent than SNO-AGPa. © FASEB.

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