Bárbara Figueira Gomes, Mario Roberto Senger, José Teófilo Moreira-Filho, Fabio Jorge de Vasconcellos Junior, Rafael Ferreira Dantas, Raymond Owens, Carolina Horta Andrade, Bruno Junior Neves, Floriano Paes Silva-Junior
{"title":"Discovery of new Schistosoma mansoni aspartyl protease inhibitors by structure-based virtual screening.","authors":"Bárbara Figueira Gomes, Mario Roberto Senger, José Teófilo Moreira-Filho, Fabio Jorge de Vasconcellos Junior, Rafael Ferreira Dantas, Raymond Owens, Carolina Horta Andrade, Bruno Junior Neves, Floriano Paes Silva-Junior","doi":"10.1590/0074-02760230031","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Schistosomiasis is a neglected tropical disease caused by trematodes of the genus Schistosoma, with a limited treatment, mainly based on the use of praziquantel (PZQ). Currently, several aspartic proteases genes have already been identified within the genome of Schistosoma species. At least one enzyme encoded from this gene family (SmAP), named SmCD1, has been validated for the development of schistosomicidal drugs, since it has a key role in haemoglobin digestion by worms.</p><p><strong>Objective: </strong>In this work, we integrated a structure-based virtual screening campaign, enzymatic assays and adult worms ex vivo experiments aiming to discover the first classes of SmCD1 inhibitors.</p><p><strong>Methods: </strong>Initially, the 3D-structures of SmCD1, SmCD2 and SmCD3 were generated using homology modelling approach. Using these models, we prioritised 50 compounds from 20,000 compounds from ChemBridge database for further testing in adult worm aqueous extract (AWAE) and recombinant SmCD1 using enzymatic assays.</p><p><strong>Findings: </strong>Seven compounds were confirmed as hits and among them, two compounds representing new chemical scaffolds, named 5 and 19, had IC50 values against SmCD1 close to 100 μM while presenting binding efficiency indexes comparable to or even higher than pepstatin, a classical tight-binding peptide inhibitor of aspartyl proteases. Upon activity comparison against mammalian enzymes, compound 50 was selective and the most potent against the AWAE aspartic protease activity (IC50 = 77.7 μM). Combination of computational and experimental results indicate that compound 50 is a selective inhibitor of SmCD2. Compounds 5, 19 and 50 tested at low concentrations (10 uM) were neither cytotoxic against WSS-1 cells (48 h) nor could kill adult worms ex-vivo, although compounds 5 and 50 presented a slight decrease on female worms motility on late incubations times (48 or 72 h).</p><p><strong>Main conclusion: </strong>Overall, the inhibitors identified in this work represent promising hits for further hit-to-lead optimisation.</p>","PeriodicalId":18469,"journal":{"name":"Memorias do Instituto Oswaldo Cruz","volume":"118 ","pages":"e230031"},"PeriodicalIF":2.5000,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10481938/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Memorias do Instituto Oswaldo Cruz","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1590/0074-02760230031","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"PARASITOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Background: Schistosomiasis is a neglected tropical disease caused by trematodes of the genus Schistosoma, with a limited treatment, mainly based on the use of praziquantel (PZQ). Currently, several aspartic proteases genes have already been identified within the genome of Schistosoma species. At least one enzyme encoded from this gene family (SmAP), named SmCD1, has been validated for the development of schistosomicidal drugs, since it has a key role in haemoglobin digestion by worms.
Objective: In this work, we integrated a structure-based virtual screening campaign, enzymatic assays and adult worms ex vivo experiments aiming to discover the first classes of SmCD1 inhibitors.
Methods: Initially, the 3D-structures of SmCD1, SmCD2 and SmCD3 were generated using homology modelling approach. Using these models, we prioritised 50 compounds from 20,000 compounds from ChemBridge database for further testing in adult worm aqueous extract (AWAE) and recombinant SmCD1 using enzymatic assays.
Findings: Seven compounds were confirmed as hits and among them, two compounds representing new chemical scaffolds, named 5 and 19, had IC50 values against SmCD1 close to 100 μM while presenting binding efficiency indexes comparable to or even higher than pepstatin, a classical tight-binding peptide inhibitor of aspartyl proteases. Upon activity comparison against mammalian enzymes, compound 50 was selective and the most potent against the AWAE aspartic protease activity (IC50 = 77.7 μM). Combination of computational and experimental results indicate that compound 50 is a selective inhibitor of SmCD2. Compounds 5, 19 and 50 tested at low concentrations (10 uM) were neither cytotoxic against WSS-1 cells (48 h) nor could kill adult worms ex-vivo, although compounds 5 and 50 presented a slight decrease on female worms motility on late incubations times (48 or 72 h).
Main conclusion: Overall, the inhibitors identified in this work represent promising hits for further hit-to-lead optimisation.
期刊介绍:
Memórias do Instituto Oswaldo Cruz is a journal specialized in microbes & their vectors causing human infections. This means that we accept manuscripts covering multidisciplinary approaches and findings in the basic aspects of infectious diseases, e.g. basic in research in prokariotes, eukaryotes, and/or virus. Articles must clearly show what is the main question to be answered, the hypothesis raised, and the contribution given by the study.
Priority is given to manuscripts reporting novel mechanisms and general findings concerning the biology of human infectious prokariotes, eukariotes or virus. Papers reporting innovative methods for diagnostics or that advance the basic research with these infectious agents are also welcome.
It is important to mention what we do not publish: veterinary infectious agents research, taxonomic analysis and re-description of species, epidemiological studies or surveys or case reports and data re-analysis. Manuscripts that fall in these cases or that are considered of low priority by the journal editorial board, will be returned to the author(s) for submission to another journal.