Identification of antiparasitic drug targets using a multi-omics workflow in the acanthocephalan model.
作者: Hanno Schmidt ; Katharina Mauer ; Manuel Glaser ; Bahram Sayyaf Dezfuli ; Sören Lukas Hellmann ; Ana Lúcia Silva Gomes ; Falk Butter ; Rebecca C Wade ; Thomas Hankeln ; Holger Herlyn
With the expansion of animal production, parasitic helminths are gaining increasing economic importance. However, application of several established deworming agents can harm treated hosts and environment due to their low specificity. Furthermore, the number of parasite strains showing resistance is growing, while hardly any new anthelminthics are being developed. Here, we present a bioinformatics workflow designed to reduce the time and cost in the development of new strategies against parasites. The workflow includes quantitative transcriptomics and proteomics, 3D structure modeling, binding site prediction, and virtual ligand screening. Its use is demonstrated for Acanthocephala (thorny-headed worms) which are an emerging pest in fish aquaculture. We included three acanthocephalans (Pomphorhynchus laevis, Neoechinorhynchus agilis, Neoechinorhynchus buttnerae) from four fish species (common barbel, European eel, thinlip mullet, tambaqui).
The workflow led to eleven highly specific candidate targets in acanthocephalans. The candidate targets showed constant and elevated transcript abundances across definitive and accidental hosts, suggestive of constitutive expression and functional importance. Hence, the impairment of the corresponding proteins should enable specific and effective killing of acanthocephalans. Candidate targets were also highly abundant in the acanthocephalan body wall, through which these gutless parasites take up nutrients. Thus, the candidate targets are likely to be accessible to compounds that are orally administered to fish. Virtual ligand screening led to ten compounds, of which five appeared to be especially promising according to ADMET, GHS, and RO5 criteria: tadalafil, pranazepide, piketoprofen, heliomycin, and the nematicide derquantel.
The combination of genomics, transcriptomics, and proteomics led to a broadly applicable procedure for the cost- and time-saving identification of candidate target proteins in parasites. The ligands predicted to bind can now be further evaluated for their suitability in the control of acanthocephalans. The workflow has been deposited at the Galaxy workflow server under the URL tinyurl.com/yx72rda7 .
2003-06-01·British Journal of Pharmacology2区 · 医学
Selective activation by photodynamic action of cholecystokinin receptor in the freshly isolated rat pancreatic acini
2区 · 医学
作者: An, Yu Ping ; Xiao, Rui ; Cui, Hong ; Cui, Zong Jie
1 Sulphonated aluminium phthalocyanine (SALPC) photodynamic action induces amylase secretion and permanent calcium oscillation in rat pancreatic acinar cells, because of the activation of phospholipase C or signalling proteins upstream. The aim of the present study was to investigate the involvement of muscarinic acetylcholine and cholecystokinin (CCK) receptors. 2 Muscarinic receptor antagonist atropine (10 micro M) blocked amylase secretion induced by bethanechol (100 micro M), and CCK(1) receptor antagonist (S)-N-[1-(2-fluorophenyl)-3,4,6,7-tetrahydor-4-oxo-pyrrolo-[3,2,1-jk][1,4] benzodiazepine-3yl]-1H-indole-2-carboxamide (FK480) (1 micro M) blocked amylase secretion induced by CCK (100 pM). 3 Amylase secretion induced by SALPC photodynamic action was not inhibited when atropine and FK480 were present during photodynamic action. However, addition of FK480 1 micro M after initiation of photodynamic action inhibited photodynamic amylase secretion. Bethanechol (10, 100 micro M) added after photodynamic action resulted in a full secretory response. 4 Atropine (10 nM) abolished calcium oscillation induced by bethanechol (5 micro M), and FK480 (10 nM) blocked calcium oscillation induced by CCK (10 pM). 5 Atropine up to 10 micro M was without effect on Ca(2+) oscillation triggered by photodynamic action, but these oscillations were abolished by FK480 (10 nM). FK480 (10 nM) had no effect on calcium oscillations induced by bethanechol (5 micro M). Bethanechol 5 micro M, added after FK480 blockade of photodynamic calcium oscillation, still triggered regular calcium oscillation. 6 It is concluded that SALPC photodynamic action selectively and permanently activates CCK receptor in rat pancreatic acini. Such permanent and selective modulation of signalling proteins has important implications for the treatment of pancreatitis, prion diseases, and neurodegenerative disorders.
2003-05-01·Drug Metabolism and Disposition2区 · 医学
Utility of hepatocytes in predicting drug metabolism: Comparison of hepatic intrinsic clearance in rats and humans in vivo and in vitro
We investigated hepatic in vitro intrinsic clearance (CL(int,in vitro)) in freshly isolated or cryopreserved hepatocytes and compared with CL(int,in vivo) by using nine model compounds, FK1052, FK480, diazepam, diltiazem, troglitazone, quinotolast, FK079, zidovudine, and acetaminophen, in rats and humans. The compounds showed a broad range of in vivo hepatic extraction ratios (rat, 0.05-0.93; humans, 0.03-0.76) and were metabolized by hepatic P450, UDP-glucuronosyltransferase, sulfotransferase, and/or esterase. CL(int,in vitro) was determined from substrate disappearance rate at 1 microM in hepatocytes. CL(int,in vivo) was calculated from in vivo pharmacokinetic data using two frequently used mathematical models (the well stirred and dispersion models). When estimating rat CL(int,in vitro) in freshly isolated hepatocytes, the rat scaling factor values (CL(int,in vivo)/CL(int,in vitro)) showed marked difference among the model compounds (0.2-73.1-fold). The rat CL(int,in vitro) values in freshly isolated hepatocytes were in good agreement with these in cryopreserved hepatocytes. Human CL(int,in vitro) were determined by use of cryopreserved hepatocytes. When human CL(int,in vitro) was regarded as the predicted CL(int,in vivo), the observed and predicted CL(int,in vivo) for FK1052, FK480, troglitazone, and FK079 differed markedly (12.4-199.0-fold). In contrast, using human CL(int,in vitro) corrected with the rat scaling factors yielded better predictions of CL(int,in vivo) that were mostly within 5-fold of the actual values. These results make the evaluation using hepatocytes more useful and provide a basis for predicting hepatic clearance using hepatocytes.