Multidrug resistance-associated protein 4 is a bile transporter of Clonorchis sinensis simulated by in silico docking

Abstract

BackgroundMultidrug resistance-associated protein 4 (MRP4) is a member of the C subfamily of the ABC family of ATP-binding cassette (ABC) transporters. MRP4 regulates ATP-dependent efflux of various organic anionic substrates and bile acids out of cells. Since Clonorchis sinensis lives in host’s bile duct, accumulation of bile juice can be toxic to the worm’s tissues and cells. Therefore, C. sinensis needs bile transporters to reduce accumulation of bile acids within its body.ResultsWe cloned MRP4 (CsMRP4) from C. sinensis and obtained a cDNA encoding an open reading frame of 1469 amino acids. Phylogenetic analysis revealed that CsMRP4 belonged to the MRP/SUR/CFTR subfamily. A tertiary structure of CsMRP4 was generated by homology modeling based on multiple structures of MRP1 and P-glycoprotein. CsMRP4 had two membrane-spanning domains (MSD1 & 2) and two nucleotide-binding domains (NBD1 & 2) as common structural folds. Docking simulation with nine bile acids showed that CsMRP4 transports bile acids through the inner cavity. Moreover, it was found that CsMRP4 mRNA was more abundant in the metacercariae than in the adults. Mouse immune serum, generated against the CsMRP4-NBD1 (24.9 kDa) fragment, localized CsMRP4 mainly in mesenchymal tissues and oral and ventral suckers of the metacercariae and the adults.ConclusionsOur findings shed new light on MRPs and their homologs and provide a platform for further structural and functional investigations on the bile transporters and parasites’ survival.Electronic supplementary materialThe online version of this article (10.1186/s13071-017-2523-8) contains supplementary material, which is available to authorized users.

Structure-based discovery of potential inhibitors targeting sodium-bile acid co-transporter of carcinogenic liver fluke Clonorchis sinensis

“…To obtain reliable homologous models of parasites, combined approach of 3D modeling methods and re nement were employed [17,18,19,58,59,60]. All predicted 3D models of IF-CsSBAT were evaluated using homology modeling programs such as Swiss-Model [28], IntFOLD [29], Phyre2 [30], RaptorX [31], and HHpred [32], and threading-based modeling program such as I-TASSER [33] (Table 1).…”

“…iii) The compound to be identi ed as a competitive inhibitor of taurocholate should reveal higher a nity than natural bile acids, ranging from −6.2 to −9.0 kcal/mol [25]. Theoretically, the binding energies of several bile acids against IF-CsSBAT and OF-CsSBAT conformations ranged from −6.1 to −8.7 kcal/mol (Table 3) [19]; however, those of HsASBT (CsSBAT homolog) were −9.0 kcal/mol and −9.2 kcal/mol against natural bile acids and PATD (lead compound blocking HsASBT), respectively [25]. Thus, a cut-off value was set at −9.2 kcal/mol since the present study aimed to explore the most probable inhibitor candidates binding to CsSBAT.…”

Clonorchis sinensis secretory protein CsAg17 vaccine induces immune protection

“…The recombinant CsAg17 partial protein was dialyzed against 1× PBS and subjected to 12% gradient gel electrophoresis. Polyclonal antibodies were produced by immunizing BALB/c mice with the recombinant CsAg17 partial protein and used for immunohistochemical staining of C. sinensis adults [17].…”

Structure-based Discovery of Potential Inhibitors Targeting Sodium-bile Acid Co-transporter of Carcinogenic Liver Fluke Clonorchis Sinensis

“…iii) The compound to be identi ed as a competitive inhibitor of taurocholate should reveal higher a nity than natural bile acids, ranging from − 6.2 to − 9.0 kcal/mol [25]. Theoretically, the binding energies of several bile acids against IF-CsSBAT and OF-CsSBAT conformations ranged from − 6.1 to − 8.7 kcal/mol (Table 3) [19]; however, those of HsASBT (CsSBAT homolog) were − 9.0 kcal/mol and − 9.2 kcal/mol against natural bile acids and poly(acrylic acid)-tetraDOCA conjugate (PATD; lead compound blocking HsASBT), respectively [25]. Thus, a cut-off value was set at − 9.2 kcal/mol since the present study aimed to explore the most probable inhibitor candidates binding to CsSBAT.…”

“…Notably, bile acids trigger physiological stimuli; however, these metabolites can have detrimental effects on C. sinensis survival, as evidence suggests that the accumulated bile acids can cause toxicity to the worm's tissues and cells [18,19]. Recent studies reported that bile components can be toxic or detrimental to C. sinensis survival [10,20,21].…”