Synthesis and in silico and in vitro evaluation of trimethoxy-benzamides designed as anti-prion derivatives
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Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are neurodegenerative disorders which affect mammals, including the human species, and arise after the conversion of the monomeric cellular prion protein (PrPC) into the aggregated scrapie form (PrPSc). There is no therapy to treat TSEs and the identification of compounds that bind PrPC, preventing its conversion into PrPSc, is a viable therapeutic strategy. We designed and synthesized six novel trimethoxy-benzamide compounds as anti-prion drug candidates. Molecular docking analyses predicted that all the derivatives bind to a hotspot region located in the PrP globular domain with very similar spatial orientation and interaction mode. Although none of the analogs inhibited in vitro-aggregation of recombinant PrP (rPrP) in a cell-free conversion assay, the RT-QuIC, compound 8a accelerated rPrP conversion into PrPSc-like species. STD-NMR and ITC analyses indicated that both 8a and 8b bind to rPrP90–231. These analogs were toxic to PrPSc-infected cell lines, hence we could not assess their anti-prion activity by using this cellular approach, although this toxicity was cell line-dependent. These results point out that the 4-amino-quinoline trimethoxy-benzamide scaffold described herein represents a novel chemical pattern useful as a starting point for future structural optimization in the design of PrP ligands with improved affinity and safety profiles.
KeywordsPrion protein Anti-prion drug Therapy Anti-scrapie compounds Molecular hybridization Prion strains
The authors thank the Faculty of Pharmacy of the Federal University of Rio de Janeiro (FF-UFRJ, BR); the Laboratory for the Support of Technological Development of the Federal University of Rio de Janeiro (LADETEC-UFRJ, BR); the Laboratory of Evaluation and Synthesis of Bioactive Substances of the Federal University of Rio de Janeiro (LASSBio-UFRJ, BR); the Laboratory of Persistent Viral Diseases from Rocky Mountain Laboratories of the National Institutes of Health (USA); and the funding agencies INCT-INOFAR (BR), CAPES (BR), CNPq (BR) and FAPERJ (BR) for fellowship and financial support. The authors thank the LAMAR laboratory, from Walter Mors Institute of Research on Natural Products, Federal University of Rio de Janeiro (IPPN-UFRJ, BR) for NMR analysis. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brazil (CAPES) - Finance Code 001.
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Conflict of interest
The authors declare that they have no conflict of interest.
- Caughey B, Baron GS, Chesebro B, Jeffrey M (2009) Getting a grip on prions: oligomers, amyloids, and pathological membrane interactions. Annu Rev Biochem 78:177–204. https://doi.org/10.1146/annurev.biochem.78.082907.145410 CrossRefPubMedPubMedCentralGoogle Scholar
- Ferreira NC, Ascari LM, Hughson AG et al. (2018) A promising antiprion trimethoxychalcone binds to the globular domain of the cellular prion protein and changes its cellular location. Antimicrob Agents Chemother 62:e01441-17. https://doi.org/10.1128/AAC.01441-17 CrossRefPubMedPubMedCentralGoogle Scholar
- Hyeon JW, Kim SY, Lee SM et al. (2017) Anti-prion screening for acridine, dextran, and tannic acid using real time–quaking induced conversion: a comparison with PrPSc-infected cell screening. PLoS ONE 12:e0170266. https://doi.org/10.1371/journal.pone.0170266 CrossRefPubMedPubMedCentralGoogle Scholar
- Kocisko DA, Baron GS, Rubenstein R et al. (2003) New inhibitors of scrapie-associated prion protein formation in a library of 2000 drugs and natural products. J Virol. https://doi.org/10.1128/JVI.77.19.10288
- Langella E, Improta R, Crescenzi O, Barone V (2006) Assessing the acid-base and conformational properties of histidine residues in human prion protein (125-228) by means of pKa calculations and molecular dynamics simulations. Proteins Struct Funct Bioinforma 64:167–177. https://doi.org/10.1002/prot.20979 CrossRefGoogle Scholar
- Mallikarjuna SM, Sandeepa C, Padmashali B (2016) Synthesis, antimicrobial activity of piperazin-1-yl (3,4,5-trimethoxyphenyl)methanone derivatives. Der Pharma Chem 8:262–268Google Scholar
- Orru CD, Groveman BR, Hughson AG et al. (2017) RT-QuIC assays for prion disease detection and diagnostics. Methods Mol Biol 1658:185–203. https://doi.org/10.1016/B978-0-12-800946-8.00031-3 CrossRefPubMedGoogle Scholar
- Otto M, Cepek L, Ratzka P et al. (2004) Efficacy of flupirtine on cognitive function in patients with CJD: a double-blind study. Neurology 62:714–718. https://doi.org/10.1212/01.WNL.0000113764.35026.EF CrossRefPubMedGoogle Scholar
- Trivedi MK, Branton A, Trivedi D, Nayak G (2016) Determination of isotopic abundance of 13C/12C or 2H/1H and 18O/16O in biofield energy treated 1-chloro-3-nitrobenzene (3-CNB) using gas chromatography-mass spectrometry. Sci J Anal Chem 4:42–51. https://doi.org/10.11648/j.sjac.20160404.11 CrossRefGoogle Scholar