Characterization of the antioxidant enzyme, thioredoxin peroxidase, from the carcinogenic human liver fluke, Opisthorchis viverrini

Suttiprapa, Sutas, Loukas, Alex, Laha, Thewarach, Wongkham, Sopit, Kaewkes, Sasithorn, Gaze, Soraya, Brindley, Paul J., and Banchob, Sripa (2008) Characterization of the antioxidant enzyme, thioredoxin peroxidase, from the carcinogenic human liver fluke, Opisthorchis viverrini. Molecular and Biochemical Parasitology, 160 (2). pp. 116-122.

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Abstract

The human liver fluke, Opisthorchis viverrini, induces inflammation of the hepatobiliary system. Despite being constantly exposed to inimical oxygen radicals released from inflammatory cells, the parasite survives for many years. The mechanisms by which it avoids oxidative damage are unknown. In this study, thioredoxin peroxidase (TPx), a member of the peroxiredoxin superfamily, was cloned from an O. viverrini cDNA library. O. viverrini TPx cDNA encoded a polypeptide of 212 amino acid residues, of molecular mass 23.57 kDa. The putative amino acid sequence shared 60–70% identity with TPXs from other helminths and from mammals, and phylogenetic analysis revealed a close relationship between TPxs from O. viverrini and other trematodes. Recombinant O. viverrini TPx was expressed as soluble protein in Escherichia coli. The recombinant protein dimerized, and its antioxidant activity was deduced by observing protection of nicking of supercoiled plasmid DNA by hydroxyl radicals. Antiserum raised against O. viverrini TPx recognized native proteins from egg, metacercaria and adult developmental stages of the liver fluke and excretory–secretory products released by adult O. viverrini. Immunolocalization studies revealed ubiquitous expression of TPx in O. viverrini organs and tissues. TPx was also detected in bile fluid and bile duct epithelial cells surrounding the flukes 2 weeks after infection of hamsters with O. viverrini. In addition, TPx was observed in the secondary (small) bile ducts where flukes cannot reach due to their large size. These results suggested that O. viverrini TPx plays a significant role in protecting the parasite against damage induced by reactive oxygen species from inflammation.

Item ID: 18509
Item Type: Article (Refereed Research - C1)
Keywords: liver fluke; Opisthorchis viverrini; peroxiredoxin; thioredoxin peroxidase; thiol-specific antioxidant; antioxidant enzyme
Additional Information:

This work was supported by NIH-NIAID, award number AI065871, the Sandler Family Foundation and the Thailand-Tropical Diseases Research Programme (T-2, grant number ID 02-2-HEL-05-054). Sutas Suttiprapa is a Royal Golden Jubilee PhD scholar through the laboratory of Dr. Banchob Sripa. AL is supported by a senior research fellowship fromtheNational Health andMedical Research Council (Australia).

ISSN: 1872-9428
Date Deposited: 26 Sep 2011 06:43
FoR Codes: 11 MEDICAL AND HEALTH SCIENCES > 1108 Medical Microbiology > 110803 Medical Parasitology @ 100%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920109 Infectious Diseases @ 100%
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