Differential Activation of Diverse Glutathione Transferases of Clonorchis sinensis in Response to the Host Bile and Oxidative Stressors

Abstract

Background Clonorchis sinensis causes chronic cumulative infections in the human hepatobiliary tract and is intimately associated with cholangiocarcinoma. Approximately 35 million people are infected and 600 million people are at risk of infections worldwide. C. sinensis excretory-secretory products (ESP) constitute the first-line effector system affecting the host-parasite interrelationship by interacting with bile fluids and ductal epithelium. However, the secretory behavior of C. sinensis in an environment close to natural host conditions is unclear. C. sinensis differs from Fasciola hepatica in migration to, and maturation in, the hepatic bile duct, implying that protein profile of the ESP of these two trematodes might be different from each other.Methodology/Principal FindingsWe conducted systemic approaches to analyze the C. sinensis ESP proteome and the biological reactivity of C. sinensis glutathione transferases (GSTs), such as global expression patterns and induction profiles under oxidative stress and host bile. When we observed ex host excretion behavior of C. sinensis in the presence of 10% host bile, the global proteome pattern was not significantly altered, but the amount of secretory proteins was increased by approximately 3.5-fold. Bioactive molecules secreted by C. sinensis revealed universal/unique features in relation to its intraluminal hydrophobic residing niche. A total of 38 protein spots identified abundantly included enzymes involved in glucose metabolism (11 spots, 28.9%) and diverse-classes of glutathione transferases (GSTs; 10 spots, 26.3%). Cathepsin L/F (four spots, 10.5%) and transporter molecules (three spots, 7.9%) were also recognized. The universal secretory proteins found in other parasites, such as several enzymes involved in glucose metabolism and oxygen transporters, were commonly detected. C. sinensis secreted less cysteine proteases and fatty acid binding proteins compared to other tissue-invading or intravascular trematodes. Interestingly, secretion of a 28 kDa σ-class GST (Cs28σGST3) was significantly affected by the host bile, involving reduced secretion of the 28 kDa species and augmented secretion of Cs28σGST3-related high-molecular-weight 85 kDa protein. Oxidative stressors induced upregulated secretion of 28 kDa Cs28σGST3, but not an 85 kDa species. A secretory 26 kDa μ-class GST (Cs26μGST2) was increased upon treatment with oxidative stressors and bile juice, while another 28 kDa σ-class GST (Cs28σGST1) showed negligible responses.Conclusions/SignificanceOur results represent the first analysis of the genuine nature of the C. sinensis ESP proteome in the presence of host bile mimicking the natural host environments. The behavioral patterns of migration and maturation of C. sinensis in the bile ducts might contribute to the secretion of copious amounts of diverse GSTs, but a smaller quantity and fewer kinds of cysteine proteases. The Cs28σGST1 and its paralog(s) detoxify endogenous oxidative molecules, while Cs28σGST3 and Cs26μGST2 conjugate xenobiotics/hydrophobic...

The helminth parasite proteome at the host–parasite interface – Informing diagnosis and control

“…The helminth parasite, Clonorchis sinensis, secretes GST, which detoxifies molecules. When C. sinensis is exposed to environmental stress, the expression of GST is upregulated (Bae et al, 2013). In the ESP of F. hepatica GST was also found (Jefferies et al, 2001).…”

“…Parasites secrete proteins that regulate the immune response and are important for evasion, nutrition and for detoxifying cytotoxic molecules (Bae et al, 2013). It appears that the ESP does not differ much between different helminth species (Victor et al, 2012), which indicates that different helminth parasites use the same proteins to protect themselves and to alter the immune response of the host (Guillou et al, 2007;Liu et al, 2009).…”

Genomics of worms, with an emphasis on Opisthorchis viverrini — opportunities for fundamental discovery and biomedical outcomes

“…Inside the bile duct, the fluke likely protects itself using a repertoire of antioxidants, such as intra-and extra-cellular superoxide dismutases (SODs), which convert free radicals to hydrogen peroxide, and via glutathione-S-tranferases (GSTs) to reduce lipid hydroperoxides and detoxify xenobiotic substrates (Trauner and Boyer, 2003). Indeed, secretory GSTs are expressed in the fluke in response to human bile (Bae et al, 2013). Like other flukes (Sanchez-Moreno et al, 1987), O. viverrini lacks catalases, and employs glutathione-like and peroxiredoxin peroxidases to convert hydrogen peroxide to water.…”

Egg-specific expression of protein with DNA methyltransferase activity in the biocarcinogenic liver fluke Clonorchis sinensis

“…Adult C. sinensis worms were isolated from the hepatobiliary tract of experimentally infected rats, as described in a previous report (Bae et al 2013b). The worms were homogenized in Triton Extraction Buffer (TEB: PBS containing 0·5% [v/v] Triton X-100 and a protease inhibitor cocktail [complete; Roche Diagnostics GmbH, Mannheim, Germany]) using a Dounce tissue grinder (Wheaton, Millville, NJ, USA).…”