{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T19:19:31Z","timestamp":1791400771707,"version":"4.3.3"},"reference-count":50,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2022,8,5]],"date-time":"2022-08-05T00:00:00Z","timestamp":1659657600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004784","name":"Novartis Stiftung\u00a0f\u00fcr\u00a0Medizinisch-Biologische Forschung","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100004784","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001711","name":"Schweizerischer Nationalfonds zur F\u00f6rderung der Wissenschaftlichen Forschung","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100001711","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000738","name":"U.S. Department of Veterans Affairs","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100000738","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Vet. Sci."],"abstract":"<jats:p>Alveolar echinococcosis is caused by the metacestode stage of the zoonotic parasite <jats:italic>Echinococcus multilocularis<\/jats:italic>. Current chemotherapeutic treatment options rely on benzimidazoles, which have limited curative capabilities and can cause severe side effects. Thus, novel treatment options are urgently needed. In search for novel targetable pathways we focused on the mitochondrial energy metabolism of <jats:italic>E. multilocularis<\/jats:italic>. The parasite relies hereby on two pathways: The classical oxidative phosphorylation including the electron transfer chain (ETC), and the anaerobic malate dismutation (MD). We screened 13 endochin-like quinolones (ELQs) <jats:italic>in vitro<\/jats:italic> for their activities against two isolates of <jats:italic>E. multilocularis<\/jats:italic> metacestodes and isolated germinal layer cells by the phosphoglucose isomerase (PGI) assay and the CellTiter Glo assay. For the five most active ELQs (ELQ-121, ELQ-136, ELQ-271, ELQ-400, and ELQ-437), EC<jats:sub>50<\/jats:sub> values against metacestodes were assessed by PGI assay, and IC<jats:sub>50<\/jats:sub> values against mammalian cells were measured by Alamar Blue assay. Further, the gene sequence of the proposed target, the mitochondrial cytochrome <jats:italic>b<\/jats:italic>, was analyzed. This allowed for a limited structure activity relationship study of ELQs against <jats:italic>E. multilocularis<\/jats:italic>, including analyses of the inhibition of the two functional sites of the cytochrome <jats:italic>b<\/jats:italic>. By applying the Seahorse XFp Extracellular Flux Analyzer, oxygen consumption assays showed that ELQ-400 inhibits the <jats:italic>E. multilocularis<\/jats:italic> cytochrome <jats:italic>bc<\/jats:italic><jats:sub>1<\/jats:sub> complex under normoxic conditions. When tested under anaerobic conditions, ELQ-400 was hardly active against <jats:italic>E. multilocularis<\/jats:italic> metacestodes. These results were confirmed by transmission electron microscopy. ELQ-400 treatment increased levels of parasite-released succinate, the final electron acceptor of the MD. This suggests that the parasite switched to MD for energy generation. Therefore, MD was inhibited with quinazoline, which did not induce damage to metacestodes under anaerobic conditions. However, it reduced the production of succinate compared to control treated parasites (i.e., inhibited the MD). The combination treatment with quinazoline strongly improved the activity of the <jats:italic>bc<\/jats:italic><jats:sub>1<\/jats:sub> inhibitor ELQ-400 against <jats:italic>E. multilocularis<\/jats:italic> metacestodes under anaerobic conditions. We conclude that simultaneous targeting of the ETC and the MD of <jats:italic>E. multilocularis<\/jats:italic> is a possible novel treatment approach for alveolar echinococcosis, and possibly also other foodborne diseases inflicted by platyhelminths, which cause substantial economic losses in livestock industry.<\/jats:p>","DOI":"10.3389\/fvets.2022.981664","type":"journal-article","created":{"date-parts":[[2022,8,5]],"date-time":"2022-08-05T06:13:18Z","timestamp":1659679998000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":20,"title":["Dual inhibition of the Echinococcus multilocularis energy metabolism"],"prefix":"10.3389","volume":"9","author":[{"given":"Sheena","family":"Chaudhry","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Raphael","family":"Zurbriggen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mat\u00edas","family":"Preza","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tobias","family":"K\u00e4mpfer","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marc","family":"Kaethner","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Roman","family":"Memedovski","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nathalie","family":"Scorrano","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrew","family":"Hemphill","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joseph Stone","family":"Doggett","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Britta","family":"Lundstr\u00f6m-Stadelmann","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2022,8,5]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"161","DOI":"10.2807\/1560-7917.ES.2018.23.9.17-00161","article-title":"The Euro-Fbp workshop participants. Prioritisation of food-borne parasites in Europe, 2016","volume":"23","author":"Bouwknegt","year":"2018","journal-title":"Euro Surveill Bull Eur Sur Mal Transm Eur Commun Dis Bull."},{"key":"B2","doi-asserted-by":"publisher","first-page":"79","DOI":"10.1016\/j.vetpar.2011.07.017","article-title":"The socioeconomic burden of parasitic zoonoses: global trends","volume":"182","author":"Torgerson","year":"2011","journal-title":"Vet Parasitol."},{"key":"B3","doi-asserted-by":"publisher","first-page":"259","DOI":"10.1016\/bs.apar.2016.09.006","article-title":"The echinococcoses: diagnosis, clinical management and burden of disease","volume":"96","author":"Kern","year":"2017","journal-title":"Adv Parasitol."},{"key":"B4","doi-asserted-by":"publisher","first-page":"213","DOI":"10.1016\/bs.apar.2016.11.002","article-title":"Ecology and life cycle patterns of echinococcus species","volume":"95","author":"Romig","year":"2017","journal-title":"Adv Parasitol."},{"key":"B5","doi-asserted-by":"publisher","first-page":"10","DOI":"10.1186\/2041-9139-5-10","article-title":"The unique stem cell system of the immortal larva of the human parasite Echinococcus multilocularis","volume":"5","author":"Koziol","year":"2014","journal-title":"Evodevo"},{"key":"B6","doi-asserted-by":"publisher","first-page":"e00040","DOI":"10.1016\/j.fawpar.2019.e00040","article-title":"The importance of being parasiticidal: an update on drug development for the treatment of alveolar echinococcosis","volume":"15","author":"Lundstr\u00f6m-Stadelmann","year":"2019","journal-title":"Food Waterborne Parasitol."},{"key":"B7","doi-asserted-by":"publisher","first-page":"1","DOI":"10.3205\/id000027","article-title":"Comprehensive diagnosis and treatment of alveolar echinococcosis: a single-center, long-term observational study of 312 patients in Germany","volume":"2017","author":"Gr\u00fcner","year":"2017","journal-title":"GMS Infect Dis."},{"key":"B8","doi-asserted-by":"publisher","first-page":"95","DOI":"10.1016\/j.ijpddr.2014.02.002","article-title":"Drug repurposing and human parasitic protozoan diseases","volume":"4","author":"Andrews","year":"2014","journal-title":"Int J Parasitol Drugs Drug Resist."},{"key":"B9","doi-asserted-by":"publisher","first-page":"27","DOI":"10.1016\/j.rvsc.2020.10.011","article-title":"Fascioliasis and fasciolopsiasis: current knowledge and future trends","volume":"134","author":"Siles-Lucas","year":"2021","journal-title":"Res Vet Sci."},{"key":"B10","doi-asserted-by":"publisher","first-page":"517","DOI":"10.1016\/j.rvsc.2020.11.010","article-title":"Echinococcus granulosus sensu lato and Echinococcus multilocularis: a review","volume":"135","author":"Woolsey","year":"2021","journal-title":"Res Vet Sci."},{"key":"B11","doi-asserted-by":"publisher","first-page":"19438","DOI":"10.1038\/s41598-019-56073-y","article-title":"In vitro metabolomic footprint of the Echinococcus multilocularis metacestode","volume":"9","author":"Ritler","year":"2019","journal-title":"Sci Rep."},{"key":"B12","doi-asserted-by":"publisher","first-page":"38001","DOI":"10.1074\/jbc.M201759200","article-title":"Succinate secreted by Trypanosoma brucei is produced by a novel and unique glycosomal enzyme, NADH-dependent fumarate reductase","volume":"277","author":"Besteiro","year":"2002","journal-title":"J Biol Chem."},{"key":"B13","doi-asserted-by":"publisher","first-page":"2535","DOI":"10.2174\/0929867033456549","article-title":"Parasite mitochondria as drug target: diversity and dynamic changes during the life cycle","volume":"10","author":"Kita","year":"2003","journal-title":"Curr Med Chem."},{"key":"B14","doi-asserted-by":"crossref","first-page":"p. 2","DOI":"10.1016\/B978-012473345-9\/50005-2","article-title":"Carbohydrate and energy metabolism in helminths","volume-title":"Biochemistry and Molecular Biology of Parasites","author":"Komuniecki","year":"1995"},{"key":"B15","doi-asserted-by":"publisher","first-page":"346","DOI":"10.1016\/0169-4758(94)90245-3","article-title":"Energy generation in parasitic helminths","volume":"10","author":"Tielens","year":"1994","journal-title":"Parasitol Today Pers Ed."},{"key":"B16","doi-asserted-by":"publisher","first-page":"102004","DOI":"10.1016\/j.parint.2019.102004","article-title":"Mitochondrial complex III in larval stage of Echinococcus multilocularis as a potential chemotherapeutic target and in vivo efficacy of atovaquone against primary hydatid cysts","volume":"75","author":"Enkai","year":"2020","journal-title":"Parasitol Int."},{"key":"B17","doi-asserted-by":"publisher","first-page":"440","DOI":"10.1016\/j.ijpddr.2018.10.011","article-title":"Repurposing of an old drug: in vitro and in vivo efficacies of buparvaquone against Echinococcus multilocularis","volume":"8","author":"Rufener","year":"2018","journal-title":"Int J Parasitol Drugs Drug Resist"},{"key":"B18","doi-asserted-by":"publisher","first-page":"3818","DOI":"10.1021\/jm500147k","article-title":"Discovery, synthesis, and optimization of antimalarial 4(1H)-quinolone-3-diarylethers","volume":"57","author":"Nilsen","year":"2014","journal-title":"J Med Chem."},{"key":"B19","doi-asserted-by":"publisher","first-page":"1977","DOI":"10.1128\/AAC.04149-14","article-title":"Subtle changes in endochin-like quinolone structure alter the site of inhibition within the cytochrome bc1 complex of Plasmodium falciparum","volume":"59","author":"Stickles","year":"2015","journal-title":"Antimicrob Agents Chemother"},{"key":"B20","doi-asserted-by":"publisher","first-page":"e00535","DOI":"10.1128\/AAC.00535-20","article-title":"Orally bioavailable endochin-like quinolone carbonate ester prodrug reduces Toxoplasma gondii brain cysts","volume":"64","author":"Doggett","year":"2020","journal-title":"Antimicrob Agents Chemother."},{"key":"B21","doi-asserted-by":"publisher","first-page":"15936","DOI":"10.1073\/pnas.1208069109","article-title":"Endochin-like quinolones are highly efficacious against acute and latent experimental toxoplasmosis","volume":"109","author":"Doggett","year":"2012","journal-title":"Proc Natl Acad Sci USA."},{"key":"B22","doi-asserted-by":"publisher","first-page":"1574","DOI":"10.1021\/acsinfecdis.8b00133","article-title":"Targeted structure-activity analysis of endochin-like quinolones reveals potent Qi and Qo site inhibitors of Toxoplasma gondii and Plasmodium falciparum cytochrome bc1 and identifies ELQ-400 as a remarkably effective compound against acute experimental toxoplasmosis","volume":"4","author":"McConnell","year":"2018","journal-title":"ACS Infect Dis."},{"key":"B23","doi-asserted-by":"publisher","first-page":"92","DOI":"10.1016\/j.ijpddr.2021.08.007","article-title":"Endochin-like quinolones (ELQs) and bumped kinase inhibitors (BKIs): synergistic and additive effects of combined treatments against Neospora caninum infection in vitro and in vivo","volume":"17","author":"Anghel","year":"2021","journal-title":"Int J Parasitol Drugs Drug Resist"},{"key":"B24","doi-asserted-by":"publisher","first-page":"285","DOI":"10.3389\/fvets.2018.00285","article-title":"Endochin-like quinolones exhibit promising efficacy against Neospora caninum in vitro and in experimentally infected pregnant mice","volume":"5","author":"Anghel","year":"2018","journal-title":"Front Vet Sci."},{"key":"B25","doi-asserted-by":"publisher","first-page":"e0066221","DOI":"10.1128\/AAC.00662-21","article-title":"Effective therapy targeting cytochrome bc1 prevents babesia erythrocytic development and protects from lethal infection","volume":"65","author":"Chiu","year":"2021","journal-title":"Antimicrob Agents Chemother."},{"key":"B26","doi-asserted-by":"publisher","first-page":"1307","DOI":"10.1084\/jem.20151519","article-title":"Radical cure of experimental babesiosis in immunodeficient mice using a combination of an endochin-like quinolone and atovaquone","volume":"213","author":"Lawres","year":"2016","journal-title":"J Exp Med."},{"key":"B27","doi-asserted-by":"publisher","first-page":"606","DOI":"10.1186\/s13071-020-04487-3","article-title":"Endochin-like quinolone-300 and ELQ-316 inhibit Babesia bovis, B. bigemina, B caballi and Theileria equi","volume":"13","author":"Silva","year":"2020","journal-title":"Parasit Vectors"},{"key":"B28","doi-asserted-by":"publisher","first-page":"96","DOI":"10.3389\/fvets.2020.00096","article-title":"Activities of endochin-like quinolones against in vitro cultured Besnoitia besnoiti Tachyzoites","volume":"7","author":"Eberhard","year":"2020","journal-title":"Front Vet Sci."},{"key":"B29","doi-asserted-by":"publisher","first-page":"164","DOI":"10.1128\/AAC.00378-07","article-title":"Anaerobic NADH-fumarate reductase system is predominant in the respiratory chain of Echinococcus multilocularis, providing a novel target for the chemotherapy of alveolar echinococcosis","volume":"52","author":"Matsumoto","year":"2008","journal-title":"Antimicrob Agents Chemother."},{"key":"B30","doi-asserted-by":"publisher","first-page":"430","DOI":"10.1007\/s00436-003-1046-8","article-title":"Long-term in vitro cultivation of Echinococcus multilocularis metacestodes under axenic conditions","volume":"92","author":"Spiliotis","year":"2004","journal-title":"Parasitol Res."},{"key":"B31","doi-asserted-by":"publisher","first-page":"1270","DOI":"10.1016\/j.meegid.2012.03.008","article-title":"Echinococcus multilocularis in Svalbard, Norway: microsatellite genotyping to investigate the origin of a highly focal contamination","volume":"12","author":"Knapp","year":"2012","journal-title":"Infect Genet Evol J Mol Epidemiol Evol Genet Infect Dis."},{"key":"B32","doi-asserted-by":"publisher","first-page":"512","DOI":"10.1093\/jac\/dkp490","article-title":"Application of an in vitro drug screening assay based on the release of phosphoglucose isomerase to determine the structure\u2013activity relationship of thiazolides against Echinococcus multilocularis metacestodes","volume":"65","author":"Stadelmann","year":"2010","journal-title":"J Antimicrob Chemother."},{"key":"B33","doi-asserted-by":"publisher","first-page":"D506","DOI":"10.1093\/nar\/gky1049","article-title":"UniProt: a worldwide hub of protein knowledge","volume":"47","year":"2019","journal-title":"Nucleic Acids Res."},{"key":"B34","doi-asserted-by":"publisher","first-page":"2","DOI":"10.1016\/j.molbiopara.2016.11.005","article-title":"WormBase ParaSite \u2013 a comprehensive resource for helminth genomics","volume":"215","author":"Howe","year":"2017","journal-title":"Mol Biochem Parasitol."},{"key":"B35","doi-asserted-by":"publisher","first-page":"4876","DOI":"10.1093\/nar\/25.24.4876","article-title":"The CLUSTAL_X windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools","volume":"25","author":"Thompson","year":"1997","journal-title":"Nucleic Acids Res."},{"key":"B36","volume-title":"Bioedit: A User-Friendly Biological Sequence Alignment Editor and Analysis Program for Windows 95\/98\/ NT","author":"Hall","year":"1999"},{"key":"B37","doi-asserted-by":"publisher","first-page":"e01866","DOI":"10.1128\/AAC.01866-16","article-title":"Genetic evidence for cytochrome b Qi site inhibition by 4(1H)-Quinolone-3-Diarylethers and Antimycin in Toxoplasma gondii","volume":"61","author":"Alday","year":"2017","journal-title":"Antimicrob Agents Chemother"},{"key":"B38","doi-asserted-by":"publisher","first-page":"1346","DOI":"10.1002\/1873-3468.13035","article-title":"The antimalarial compound ELQ-400 is an unusual inhibitor of the bc1 complex, targeting both Qo and Qi sites","volume":"592","author":"Song","year":"2018","journal-title":"FEBS Lett."},{"key":"B39","doi-asserted-by":"publisher","first-page":"4853","DOI":"10.1128\/AAC.00791-16","article-title":"Atovaquone and ELQ-300 combination therapy as a novel dual-site cytochrome bc1 inhibition strategy for malaria","volume":"60","author":"Stickles","year":"2016","journal-title":"Antimicrob Agents Chemother."},{"key":"B40","doi-asserted-by":"publisher","first-page":"139","DOI":"10.1016\/S0065-308X(08)60253-5","article-title":"Electron transport in parasitic helminths and protozoa","volume":"8","author":"Bryant","year":"1970","journal-title":"Adv Parasitol."},{"key":"B41","doi-asserted-by":"publisher","first-page":"e48165","DOI":"10.7554\/eLife.48165","article-title":"Rhodoquinone biosynthesis in C. elegans requires precursors generated by the kynurenine pathway","volume":"8","author":"Del Borrello","year":"2019","journal-title":"eLife."},{"key":"B42","doi-asserted-by":"publisher","first-page":"e0009991","DOI":"10.1371\/journal.pntd.0009991","article-title":"Identification of enzymes that have helminth-specific active sites and are required for Rhodoquinone-dependent metabolism as targets for new anthelmintics","volume":"15","author":"Lautens","year":"2021","journal-title":"PLoS Negl Trop Dis."},{"key":"B43","doi-asserted-by":"publisher","first-page":"473","DOI":"10.1073\/pnas.0237315100","article-title":"Atpenins, potent and specific inhibitors of mitochondrial complex II (succinate-ubiquinone oxidoreductase)","volume":"100","author":"Miyadera","year":"2003","journal-title":"Proc Natl Acad Sci USA."},{"key":"B44","doi-asserted-by":"publisher","first-page":"15287","DOI":"10.3390\/ijms160715287","article-title":"Structural insights into the molecular design of flutolanil derivatives targeted for fumarate respiration of parasite mitochondria","volume":"16","author":"Inaoka","year":"2015","journal-title":"Int J Mol Sci."},{"key":"B45","doi-asserted-by":"publisher","first-page":"941","DOI":"10.1107\/S1744309109031352","article-title":"Crystallization of mitochondrial rhodoquinol-fumarate reductase from the parasitic nematode Ascaris suum with the specific inhibitor flutolanil","volume":"65","author":"Osanai","year":"2009","journal-title":"Acta Crystallograph Sect F Struct Biol Cryst Commun."},{"key":"B46","doi-asserted-by":"publisher","first-page":"60","DOI":"10.1073\/pnas.98.1.60","article-title":"An anthelmintic compound, nafuredin, shows selective inhibition of complex I in helminth mitochondria","volume":"98","author":"Omura","year":"2001","journal-title":"Proc Natl Acad Sci USA."},{"key":"B47","doi-asserted-by":"publisher","first-page":"270","DOI":"10.1016\/j.parint.2009.03.005","article-title":"Flubendazole interferes with a wide spectrum of cell homeostatic mechanisms in Echinococcus granulosus protoscoleces","volume":"58","author":"Cumino","year":"2009","journal-title":"Parasitol Int."},{"key":"B48","doi-asserted-by":"publisher","first-page":"221","DOI":"10.1016\/j.exppara.2008.07.008","article-title":"Taenia crassiceps: energetic and respiratory metabolism from cysticerci exposed to praziquantel and albendazole in vitro","volume":"120","author":"Vinaud","year":"2008","journal-title":"Exp Parasitol."},{"key":"B49","first-page":"239","article-title":"Effect of cations and anthelmintics on enzymes of respiratory chains of the cestode Hymenolepis diminuta","volume":"34","author":"Wani","year":"1994","journal-title":"Biochem Mol Biol Int"},{"key":"B50","first-page":"151","article-title":"Effects of mebendazole, albendazole, and praziquantel on succinate dehydrogenase, fumarate reductase, and malate dehydrogenase in Echinococcus granulosus cysts harbored in mice","volume":"14","author":"Xiao","year":"1993","journal-title":"Zhongguo Yao Li Xue Bao."}],"container-title":["Frontiers in Veterinary Science"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fvets.2022.981664\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,8,5]],"date-time":"2022-08-05T06:13:26Z","timestamp":1659680006000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fvets.2022.981664\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,8,5]]},"references-count":50,"alternative-id":["10.3389\/fvets.2022.981664"],"URL":"https:\/\/doi.org\/10.3389\/fvets.2022.981664","relation":{},"ISSN":["2297-1769"],"issn-type":[{"value":"2297-1769","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,8,5]]},"article-number":"981664"}}