ABSTRACT
OBJECTIVE: To investigate the possible effect of artesunate (ART) on schistosome thioredoxin glutathione reductase (TGR) and cytochrome c peroxidase (CcP) in Schistosoma mansoni-infected mice. METHODS: A total of 200 laboratory bred male Swiss albino mice were divided into 4 groups (50 mice in each group). Group I: infected untreated group (Control group) received a vehicle of 1% sodium carbonyl methylcellulose (CMC-Na); Group II: infected then treated with artesunate; Group III: infected then treated with praziquantel, and group IV: infected then treated with artesunate then praziquantel. Adult S. mansoni worms were collected by Animal Perfusion Method, tissue egg counted, TGR, and CcP mRNA Expression were estimated of in S. mansoni adult worms by semi-quantitative rt-PCR. RESULTS: Semi-quantitative rt-PCR values revealed that treatment with artesunate caused significant decrease in expression of schistosome TGR and CcP in comparison to the untreated group. In contrast, the treatment with praziquantel did not cause significant change in expression of these genes. The results showed more reduction in total worm and female worm count in combined ART-PZQ treated group than in monotherapy treated groups by either ART or PZQ. Moreover, complete disappearance (100%) of tissue eggs was recorded in ART-PZQ treated group with a respective reduction rate of 95.9% and 68.4% in ART- and PZQ-treated groups. CONCLUSION: The current study elucidated for the first time that anti-schistosomal mechanisms of artesunate is mediated via reduction in expression of schistosome TGR and CcP. Linking these findings, addition of artesunate to praziquantel could achieve complete cure outcome in treatment of schistosomiasis.
Subject(s)
Artemisinins/pharmacology , Cytochrome-c Peroxidase/drug effects , Multienzyme Complexes/drug effects , NADH, NADPH Oxidoreductases/drug effects , Schistosoma/drug effects , Animals , Artesunate , Cytochrome-c Peroxidase/genetics , Male , Mice , Multienzyme Complexes/genetics , NADH, NADPH Oxidoreductases/genetics , Polymerase Chain Reaction , RNA, Messenger/genetics , Schistosoma/enzymologyABSTRACT
The design of synthetic agents to disrupt protein-protein interactions has received relatively little attention in recent years. In this review we describe strategies for targeting different types of protein surfaces using mimetics of protein secondary or tertiary structure. In this way strong and selective binding to a protein surface has be achieved and disruption of clinically important protein-protein interactions has been demonstrated in models of human disease.
Subject(s)
Biochemistry/methods , Proteins/chemistry , Proteins/metabolism , Amino Acid Sequence , Chymotrypsin/antagonists & inhibitors , Chymotrypsin/drug effects , Chymotrypsin/metabolism , Cytochrome-c Peroxidase/chemistry , Cytochrome-c Peroxidase/drug effects , Cytochrome-c Peroxidase/metabolism , Cytochromes c/chemistry , Cytochromes c/drug effects , Cytochromes c/metabolism , Molecular Mimicry , Molecular Sequence Data , Organic Chemicals/chemistry , Organic Chemicals/metabolism , Organic Chemicals/pharmacology , Platelet-Derived Growth Factor/chemistry , Platelet-Derived Growth Factor/metabolism , Protein Conformation , Proteins/drug effects , Receptors, Platelet-Derived Growth Factor/chemistry , Receptors, Platelet-Derived Growth Factor/drug effects , Receptors, Platelet-Derived Growth Factor/metabolismABSTRACT
Structural change of Cytochrome c peroxidase (CcP) due to interaction with lysine peptides (Lysptds) has been studied by absorption spectra and measurements on electron transfer between cytochrome c (cyt c) and CcP in the presence of Lysptd. Peaks were observed in the difference absorption spectrum of CcP between in the presence and absence of Lysptds, demonstrating a structural perturbation of CcP, at least at its heme site, on interaction with Lysptd. The interaction between CcP and Lysptd was electrostatic, since no significant peak was detected in the difference absorption spectrum when 100 mM of NaCl was added to the solution. Lysptds competitively inhibited electron transfer from cyt c to CcP, which indicated that they interacted with CcP at the same site as cyt c and would be models of the CcP interacting site of cyt c.
Subject(s)
Cytochrome c Group/metabolism , Cytochrome-c Peroxidase/chemistry , Polylysine/pharmacology , Cytochrome-c Peroxidase/drug effects , Cytochrome-c Peroxidase/metabolism , Electron Transport/drug effects , Protein Conformation , Spectrum Analysis , Yeasts/enzymologyABSTRACT
Cytochrome c peroxidase oxidises hydrogen peroxide using cytochrome c as the electron donor. This enzyme is found in yeast and bacteria and has been also described in the trematodes Fasciola hepatica and Schistosoma mansoni. Using partially purified cytochrome c peroxidase samples from Fasciola hepatica we evaluated its role as an antioxidant enzyme via the investigation of its ability to protect against oxidative damage to deoxyribose in vitro. A system containing FeIII-EDTA plus ascorbate was used to generate reactive oxygen species superoxide radical, H2O2 as well as the hydroxyl radical. Fasciola hepatica cytochrome c peroxidase effectively protected deoxyribose against oxidative damage in the presence of its substrate cytochrome c. This protection was proportional to the amount of enzyme added and occurred only in the presence of cytochrome c. Due to the low specific activity of the final partially purified sample the effects of ascorbate and calcium chloride on cytochrome c peroxidase were investigated. The activity of the partially purified enzyme was found to increase between 10 and 37% upon reduction with ascorbate. However, incubation of the partially purified enzyme with 1 mM calcium chloride did not have any effect on enzyme activity. Our results showed that Fasciola hepatica CcP can protect deoxyribose from oxidative damage in vitro by blocking the formation of the highly toxic hydroxyl radical (.OH). We suggest that the capacity of CcP to inhibit .OH-formation, by efficiently removing H2O2 from the in vitro oxidative system, may extend the biological role of CcP in response to oxidative stress in Fasciola hepatica.
