1
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Timm BL, da Gama ANS, Batista MM, Batista DDGJ, Boykin DW, De Koning HP, Correia Soeiro MDN. Arylimidamides Have Potential for Chemoprophylaxis against Blood-Transmitted Chagas Disease. Pathogens 2023; 12:pathogens12050701. [PMID: 37242371 DOI: 10.3390/pathogens12050701] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/28/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
Chagas disease (CD) affects over 6 million people worldwide and can be transmitted iatrogenically. Crystal violet (CV) was previously used for pathogen reduction but has harmful side-effects. In the present study, three arylimidamides (AIAs) and CV were used to sterilize mice blood samples experimentally contaminated with bloodstream trypomastigotes (BT) of Trypanosoma cruzi, at non hemolytic doses. All AIAs were not toxic to mouse blood cells until the highest tested concentration (96 µM). The previous treatment of BT with the AIAs impaired the infection establishment of cardiac cell cultures. In vivo assays showed that pre-incubation of mouse blood samples with the AIAs and CV (96 µM) significantly suppressed the parasitemia peak, but only the AIA DB1831 gave ≥90% animal survival, while vehicle treated samples reached 0%. Our findings support further studies regarding the potential use of AIAs for blood bank purposes.
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Affiliation(s)
- Bruno Lisboa Timm
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21045-900, Brazil
| | | | - Marcos Meuser Batista
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21045-900, Brazil
| | - Denise da Gama Jaén Batista
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21045-900, Brazil
| | - David W Boykin
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Harry P De Koning
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G43 2DX, UK
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2
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Jonathan Nué-Martinez J, Cisneros D, Dardonville C. Methyl N-(tert-butoxycarbonyl)pyridine-2-carbimidothioate: a New Reagent for the Synthesis of N-phenylpyridinecarboxamidine (“arylimidamide”) DNA-minor groove binders from Poorly Nucleophilic Amines. Bioorg Med Chem Lett 2022; 74:128926. [DOI: 10.1016/j.bmcl.2022.128926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/03/2022] [Accepted: 08/03/2022] [Indexed: 11/26/2022]
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3
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Rhodes V, Hayes CJ, Sánchez‐Miguel C, O'Donovan J, Ryan EG. An investigation into bovine besnoitiosis (
Besnoitia besnoiti
) in an Irish pedigree Aberdeen Angus herd. VETERINARY RECORD CASE REPORTS 2022. [DOI: 10.1002/vrc2.379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Victoria Rhodes
- Section of Herd Health and Animal Husbandry School of Veterinary Medicine University College Dublin Belfield Dublin Ireland
| | - Ciara J. Hayes
- Cork Regional Veterinary Laboratory Department of Agriculture Food and the Marine Cork Ireland
| | - Cosme Sánchez‐Miguel
- Cork Regional Veterinary Laboratory Department of Agriculture Food and the Marine Cork Ireland
| | - James O'Donovan
- Cork Regional Veterinary Laboratory Department of Agriculture Food and the Marine Cork Ireland
| | - Eoin G. Ryan
- Section of Herd Health and Animal Husbandry School of Veterinary Medicine University College Dublin Belfield Dublin Ireland
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4
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Eberhard N, Balmer V, Müller J, Müller N, Winter R, Pou S, Nilsen A, Riscoe M, Francisco S, Leitao A, Doggett JS, Hemphill A. Activities of Endochin-Like Quinolones Against in vitro Cultured Besnoitia besnoiti Tachyzoites. Front Vet Sci 2020; 7:96. [PMID: 32161765 PMCID: PMC7054222 DOI: 10.3389/fvets.2020.00096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/10/2020] [Indexed: 12/14/2022] Open
Abstract
Endochin-like quinolones (ELQs) potently inhibit the proliferation of Plasmodium, Toxoplasma, Neospora, and Babesia by targeting the cytochrome b Qo and Qi sites and interfering with oxidative phosphorylation and pyrimidine biosynthesis. The activities of 14 different ELQs were assessed against B. besnoiti tachyzoites grown in human foreskin fibroblasts (HFF) by quantitative real time PCR. The values for 50% proliferation inhibition (IC50) of five ELQs were determined in a 3-days growth assay after an initial screen of 12 ELQs at 0.01, 0.1, and 1 μM. The IC50s of ELQ-121, -136, and -316 were 0.49, 2.36, and 7.97 nM, respectively. The IC50s of ELQs tested against B. besnoiti were higher than IC50s previously observed for P. falciparum and T. gondii. However, the B. besnoiti cytochrome b sequence and the predicted Qo and Qi ELQ binding sites in the Toxoplasma, Neospora, and Besnoitia cytochrome b are virtually identical, suggesting that the differences in ELQ susceptibility are not due to variations in the substrate binding sites. TEM of ELQ-treated parasites primarily demonstrated alterations within the parasite mitochondrion, profound thickening of the nuclear membrane, as well as increased vacuolization within the tachyzoite cytoplasm. Long-term treatment assays of intracellular B. besnoiti with ELQs for up to 20 days followed by the release of drug pressure caused a substantial delay in parasite growth and proliferation while ELQs were present, but parasite proliferation resumed days after ELQs were removed. Interestingly, structural alterations persisted after ELQ removal and parasite proliferation was slowed. These findings provide a basis for further in vivo studies of ELQs as therapeutic options against B. besnoiti infection.
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Affiliation(s)
- Naja Eberhard
- Vetsuisse Faculty, Institute of Parasitology, University of Bern, Bern, Switzerland
| | - Vreni Balmer
- Vetsuisse Faculty, Institute of Parasitology, University of Bern, Bern, Switzerland
| | - Joachim Müller
- Vetsuisse Faculty, Institute of Parasitology, University of Bern, Bern, Switzerland
| | - Norbert Müller
- Vetsuisse Faculty, Institute of Parasitology, University of Bern, Bern, Switzerland
| | - Rolf Winter
- VA Portland Health Care System Research and Development Service, Portland, OR, United States
| | - Soviti Pou
- VA Portland Health Care System Research and Development Service, Portland, OR, United States
| | - Aaron Nilsen
- VA Portland Health Care System Research and Development Service, Portland, OR, United States
| | - Mike Riscoe
- VA Portland Health Care System Research and Development Service, Portland, OR, United States
| | - Samuel Francisco
- Faculdade de Medicina Veterinária, CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Universidade de Lisboa, Lisbon, Portugal
| | - Alexandre Leitao
- Faculdade de Medicina Veterinária, CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Universidade de Lisboa, Lisbon, Portugal
| | - J. Stone Doggett
- VA Portland Health Care System Research and Development Service, Portland, OR, United States
| | - Andrew Hemphill
- Vetsuisse Faculty, Institute of Parasitology, University of Bern, Bern, Switzerland
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5
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Diezma-Díaz C, Ferre I, Re M, Jiménez-Meléndez A, Tabanera E, Pizarro-Díaz M, González-Huecas M, Alcaide-Pardo M, Blanco-Murcia FJ, Ortega-Mora LM, Álvarez-García G. A model for chronic bovine besnoitiosis: Parasite stage and inoculation route are key factors. Transbound Emerg Dis 2019; 67:234-249. [PMID: 31483955 DOI: 10.1111/tbed.13345] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 08/21/2019] [Accepted: 08/21/2019] [Indexed: 12/17/2022]
Abstract
In this work, an experimental model for chronic besnoitiosis in bovine was developed and characterized. Using a previously established calf model, two new variables (parasite stage and inoculation route) were combined and used. Twelve Holstein Friesian 3-month-old male calves were randomly divided into four groups of three animals each. Bradyzoites were obtained from a chronically infected bull and used for inoculation via three different inoculation routes. Three groups were inoculated with 106 bradyzoites by intravenous (G1), subcutaneous (G2) and intradermal (G3) routes, and a non-infected control group (G4) was inoculated with PBS. The trial lasted for 90 days and included daily clinical monitoring as well as weekly skin biopsies and blood sampling. Sera were obtained to analyse both cellular and humoral responses. Once the calves were euthanized, tissues from the skin, eyes, respiratory and reproductive tracts, among others, were collected to study presence of the parasite. Clinically, the infection was classified as mild to moderate for the acute stage since all infected calves showed lymphadenopathy from four days post-infection (pi) and fever from one week pi until 24 days pi. However, the most relevant results were achieved during the chronic stage that was classified as moderate to severe. In fact, pathognomonic conjunctival cysts were observed in all infected calves from 40 days pi onwards and were more abundant in G3. Moreover, one calf from this group developed skin lesions (49 days pi). The microscopic tissue cysts and Besnoitia DNA were detected primarily in skin, reproductive tract and respiratory tissue samples, and parasite load was higher in G3. In conclusion, the parasite stage (bradyzoite) and the inoculation route are key factors that influence the outcome of an infection. In particular, the intradermal route led to more severe clinical signs of the chronic phase in the inoculated calves.
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Affiliation(s)
- Carlos Diezma-Díaz
- Animal Health Department, Faculty of Veterinary Sciences, SALUVET, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain
| | - Ignacio Ferre
- Animal Health Department, Faculty of Veterinary Sciences, SALUVET, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain
| | - Michela Re
- Animal Health Department, Faculty of Veterinary Sciences, SALUVET, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain.,Animal Medicine and Surgery Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain
| | - Alejandro Jiménez-Meléndez
- Animal Health Department, Faculty of Veterinary Sciences, SALUVET, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain
| | - Enrique Tabanera
- Animal Medicine and Surgery Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain
| | - Manuel Pizarro-Díaz
- Animal Medicine and Surgery Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain
| | - Marta González-Huecas
- Animal Medicine and Surgery Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain
| | - María Alcaide-Pardo
- Animal Health Department, Faculty of Veterinary Sciences, SALUVET, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain
| | - Francisco Javier Blanco-Murcia
- Animal Health Department, Faculty of Veterinary Sciences, SALUVET, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain.,Animal Medicine and Surgery Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain
| | - Luis Miguel Ortega-Mora
- Animal Health Department, Faculty of Veterinary Sciences, SALUVET, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain
| | - Gema Álvarez-García
- Animal Health Department, Faculty of Veterinary Sciences, SALUVET, Complutense University of Madrid, Ciudad Universitaria s/n, Madrid, Spain
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6
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Jiménez-Meléndez A, Rico-San Román L, Hemphill A, Balmer V, Ortega-Mora LM, Álvarez-García G. Repurposing of commercially available anti-coccidials identifies diclazuril and decoquinate as potential therapeutic candidates against Besnoitia besnoiti infection. Vet Parasitol 2018; 261:77-85. [PMID: 30253854 DOI: 10.1016/j.vetpar.2018.08.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/20/2018] [Accepted: 08/30/2018] [Indexed: 01/07/2023]
Abstract
Repurposing of currently marketed compounds with proven efficacy against apicomplexan parasites was used as an approach to define novel candidate therapeutics for bovine besnoitiosis. Besnoitia besnoiti tachyzoites grown in MARC-145 cells were exposed to different concentrations of toltrazuril, diclazuril, imidocarb, decoquinate, sulfadiazine and trimethoprim alone or in combination with sulfadiazine. Drugs were added either just prior to infection of MARC-145 cells (0 h post infection, hpi) or at 6 hpi. A primary evaluation of drug effects was done by direct immunofluorescence staining and counting. Potential effects on the host cells were assessed using a XTT kit for cell proliferation. Compounds displaying promising efficacy were selected for IC50 and IC99 determination by qPCR. In addition, the impact of drugs on the tachyzoite ultrastructure was assessed by TEM and long-term treatment assays were performed. Cytotoxicity assays confirmed that none of the compounds affected the host cells. Decoquinate and diclazuril displayed invasion inhibition rates of 90 and 83% at 0 h pi and 73 and 72% at 6 h pi, respectively. The remaining drugs showed lower efficacy and were not further studied. Decoquinate and diclazuril exhibited IC99 values of 100 nM and 29.9 μM, respectively. TEM showed that decoquinate primarily affected the parasite mitochondrium, whilst diclazuril interfered in cytokinesis of daughter zoites. The present study demonstrates the efficacy of diclazuril and decoquinate against B. besnoiti in vitro and further assessments of safety and efficacy of both drugs should be performed in the target species.
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Affiliation(s)
- Alejandro Jiménez-Meléndez
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Laura Rico-San Román
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Andrew Hemphill
- Institute of Parasitology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012, Bern, Switzerland
| | - Vreni Balmer
- Institute of Parasitology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012, Bern, Switzerland
| | - Luis Miguel Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Gema Álvarez-García
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
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7
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Diezma-Díaz C, Jiménez-Meléndez A, Re MT, Ferre I, Ferreras MDC, Gutiérrez-Expósito D, Rojo-Montejo S, Román-Trufero A, Benavides-Silván J, García-Lunar P, Calleja-Bueno L, Blanco-Murcia J, Osoro K, Ortega-Mora LM, Álvarez-García G. Effect of parasite dose and host age on the infection with Besnoitia besnoiti
tachyzoites in cattle. Transbound Emerg Dis 2018; 65:1979-1990. [DOI: 10.1111/tbed.12980] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/09/2018] [Accepted: 07/13/2018] [Indexed: 12/25/2022]
Affiliation(s)
- Carlos Diezma-Díaz
- SALUVET; Animal Health Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
| | - Alejandro Jiménez-Meléndez
- SALUVET; Animal Health Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
| | - Michela Tatiana Re
- SALUVET; Animal Health Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
- Animal Medicine and Surgery Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
| | - Ignacio Ferre
- SALUVET; Animal Health Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
| | | | - Daniel Gutiérrez-Expósito
- SALUVET; Animal Health Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
- Livestock Health and Production Institute (ULE-CSIC); León Spain
| | - Silvia Rojo-Montejo
- SALUVET; Animal Health Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
- Regional Service for Research and Agri-Food Development (SERIDA); Animal Production Systems; Villaviciosa Spain
| | - Alicia Román-Trufero
- Regional Service for Research and Agri-Food Development (SERIDA); Animal Production Systems; Villaviciosa Spain
| | | | - Paula García-Lunar
- SALUVET; Animal Health Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
| | - Lydia Calleja-Bueno
- Animal Medicine and Surgery Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
| | - Javier Blanco-Murcia
- SALUVET; Animal Health Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
- Animal Medicine and Surgery Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
| | - Koldo Osoro
- Regional Service for Research and Agri-Food Development (SERIDA); Animal Production Systems; Villaviciosa Spain
| | - Luis-Miguel Ortega-Mora
- SALUVET; Animal Health Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
| | - Gema Álvarez-García
- SALUVET; Animal Health Department; Faculty of Veterinary Sciences; Complutense University of Madrid; Madrid Spain
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8
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In vitro treatment of Besnoitia besnoiti with the naphto-quinone buparvaquone results in marked inhibition of tachyzoite proliferation, mitochondrial alterations and rapid adaptation of tachyzoites to increased drug concentrations. Parasitology 2018; 146:112-120. [PMID: 29921336 DOI: 10.1017/s0031182018000975] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We here assessed the in vitro efficacy of the naptho-quinone buparvaquone (BPQ) against Besnoitia besnoiti tachyzoites in vitro. BPQ is currently licensed for the treatment of theileriosis in cattle in many countries, but not in the EU. In 4-day treatment assays, BPQ massively impaired tachyzoite proliferation with an IC50 of 10 ± 3 nm, and virtually complete inhibition was obtained in the presence of nm BPQ. Exposure to 1 µm BPQ leads to ultrastructural changes affecting initially the mitochondrial matrix and the cristae. After 96 h, most parasites were largely distorted, filled with cytoplasmic amylopectin granules and vacuoles containing components of unknown composition. Host cell mitochondria did not appear to be notably affected by the drug. However, upon prolonged exposure (14-16 days) to increased BPQ concentrations, B. besnoiti tachyzoites exhibited the capacity to adapt, and they resumed proliferation at dosages of up to 10 µm BPQ, albeit at a lower rate. These BPQ-adapted parasites maintained this lower susceptibility to BPQ treatment after freeze-thawing, and inspection by the transmission electron microscopy revealed that they underwent proliferation in the absence of structurally intact mitochondria.
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9
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In vitro efficacy of bumped kinase inhibitors against Besnoitia besnoiti tachyzoites. Int J Parasitol 2017; 47:811-821. [PMID: 28899692 DOI: 10.1016/j.ijpara.2017.08.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 08/25/2017] [Accepted: 08/29/2017] [Indexed: 12/30/2022]
Abstract
Besnoitia besnoiti is an apicomplexan parasite responsible for bovine besnoitiosis, a chronic and debilitating disease that causes systemic and skin manifestations and sterility in bulls. Neither treatments nor vaccines are currently available. In the search for therapeutic candidates, calcium-dependent protein kinases have arisen as promising drug targets in other apicomplexans (e.g. Neospora caninum, Toxoplasma gondii, Plasmodium spp. and Eimeria spp.) and are effectively targeted by bumped kinase inhibitors. In this study, we identified and cloned the gene coding for BbCDPK1. The impact of a library of nine bumped kinase inhibitor analogues on the activity of recombinant BbCDPK1 was assessed by luciferase assay. Afterwards, those were further screened for efficacy against Besnoitiabesnoiti tachyzoites grown in Marc-145 cells. Primary tests at 5µM revealed that eight compounds exhibited more than 90% inhibition of invasion and proliferation. The compounds BKI 1294, 1517, 1553 and 1571 were further characterised, and EC99 (1294: 2.38µM; 1517: 2.20µM; 1553: 3.34µM; 1571: 2.78µM) were determined by quantitative real-time polymerase chain reaction in 3-day proliferation assays. Exposure of infected cultures with EC99 concentrations of these drugs for up to 48h was not parasiticidal. The lack of parasiticidal action was confirmed by transmission electron microscopy, which showed that bumped kinase inhibitor treatment interfered with cell cycle regulation and non-disjunction of tachyzoites, resulting in the formation of large multi-nucleated complexes which co-existed with viable parasites within the parasitophorous vacuole. However, it is possible that, in the face of an active immune response, parasite clearance may occur. In summary, bumped kinase inhibitors may be effective drug candidates to control Besnoitiabesnoiti infection. Further in vivo experiments should be planned, as attainment and maintenance of therapeutic blood plasma levels in calves, without toxicity, has been demonstrated for BKIs 1294, 1517 and 1553.
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10
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Ryan EG, Lee A, Carty C, O'Shaughnessy J, Kelly P, Cassidy JP, Sheehan M, Johnson A, de Waal T. Bovine besnoitiosis (Besnoitia besnoiti
) in an Irish dairy herd. Vet Rec 2016; 178:608. [DOI: 10.1136/vr.103683] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2016] [Indexed: 11/04/2022]
Affiliation(s)
- E. G. Ryan
- School of Veterinary Medicine, Veterinary Sciences Centre, University College Dublin (UCD), Belfield; Dublin 4 Republic of Ireland
| | - A. Lee
- School of Veterinary Medicine, Veterinary Sciences Centre, University College Dublin (UCD), Belfield; Dublin 4 Republic of Ireland
| | - C. Carty
- School of Veterinary Medicine, Veterinary Sciences Centre, University College Dublin (UCD), Belfield; Dublin 4 Republic of Ireland
| | - J. O'Shaughnessy
- School of Veterinary Medicine, Veterinary Sciences Centre, University College Dublin (UCD), Belfield; Dublin 4 Republic of Ireland
| | - P. Kelly
- School of Veterinary Medicine, Veterinary Sciences Centre, University College Dublin (UCD), Belfield; Dublin 4 Republic of Ireland
| | - J. P. Cassidy
- School of Veterinary Medicine, Veterinary Sciences Centre, University College Dublin (UCD), Belfield; Dublin 4 Republic of Ireland
| | - M. Sheehan
- Kilkenny Regional Veterinary Laboratory; Department of Agriculture; Food and the Marine; Kilkenny Republic of Ireland
| | - A. Johnson
- Limerick Regional Veterinary Laboratory; Department of Agriculture; Food and the Marine; Limerick Republic of Ireland
| | - T. de Waal
- School of Veterinary Medicine, Veterinary Sciences Centre, University College Dublin (UCD), Belfield; Dublin 4 Republic of Ireland
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11
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Frey CF, Regidor-Cerrillo J, Marreros N, García-Lunar P, Gutiérrez-Expósito D, Schares G, Dubey JP, Gentile A, Jacquiet P, Shkap V, Cortes H, Ortega-Mora LM, Álvarez-García G. Besnoitia besnoiti lytic cycle in vitro and differences in invasion and intracellular proliferation among isolates. Parasit Vectors 2016; 9:115. [PMID: 26928430 PMCID: PMC4772326 DOI: 10.1186/s13071-016-1405-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/23/2016] [Indexed: 12/27/2022] Open
Abstract
Background Bovine besnoitiosis, caused by the protozoan Besnoitia besnoiti, reduces productivity and fertility of affected herds. Besnoitiosis continues to expand in Europe and no effective control tools are currently available. Experimental models are urgently needed. Herein, we describe for the first time the kinetics of standardised in vitro models for the B. besnoiti lytic cycle. This will aid to study the pathogenesis of the disease, in the screening for vaccine targets and drugs potentially useful for the treatment of besnoitiosis. Methods We compared invasion and proliferation of one B. tarandi (from Finland) and seven B. besnoiti isolates (Bb-Spain1, Bb-Spain2, Bb-Israel, Bb-Evora03, Bb-Ger1, Bb-France, Bb-Italy2) in MARC-145 cell culture. Host cell invasion was studied at 4, 6, 8 and 24 h post infection (hpi), and proliferation characteristics were compared at 24, 48, 72, 96, 120, and 144 hpi. Results In Besnoitia spp., the key parameters that determine the sequential adhesion-invasion, proliferation and egress steps are clearly distinct from those in the related apicomplexans Toxoplasma gondii and Neospora caninum. Besnoitia spp. host cell invasion is a rather slow process, since only 50 % of parasites were found intracellular after 3–6 h of exposure to host cells, and invasion still took place after 24 h. Invasion efficacy was significantly higher for Bb-France, Bb-Evora03 and Bb-Israel. In addition, the time span for endodyogeny to take place was as long as 18–35 h. Bb-Israel and B. tarandi isolates were most prolific, as determined by the tachyzoite yield at 72 hpi. The total tachyzoite yield could not be predicted neither by invasion-related parameters (velocity and half time invasion) nor by proliferation parameters (lag phase and doubling time (dT)). The lytic cycle of Besnoitia was asynchronous as evidenced by the presence of three different plaque-forming tachyzoite categories (lysis plaques, large and small parasitophorous vacuoles). Conclusions This study provides first insights into the lytic cycle of B. besnoiti isolates and a standardised in vitro model that allows screening of drug candidates for the treatment of besnoitiosis. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1405-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Caroline F Frey
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain. .,Institute of Parasitology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, 3012, Bern, Switzerland.
| | - Javier Regidor-Cerrillo
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
| | - Nelson Marreros
- Centre for Fish and Wildlife Health, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, 3012, Bern, Switzerland.
| | - Paula García-Lunar
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
| | - Daniel Gutiérrez-Expósito
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
| | - Gereon Schares
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald, Insel Riems, Germany.
| | - Jitender P Dubey
- United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Beltsville, MD, 20705-2350, USA.
| | - Arcangelo Gentile
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell'Emilia, Italy.
| | - Philippe Jacquiet
- Institut National Polytechnique (INP), Ecole Nationale Vétérinaire de Toulouse (ENVT), UMR1225, IHAP, Equipe « Besnoitiose et vecteurs », Université de Toulouse, Toulouse, France.
| | - Varda Shkap
- Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan, 50250, Israel.
| | - Helder Cortes
- Laboratório de Parasitologia Victor Caeiro, Núcleo da Mitra, ICAAM, Universidade de Évora, Apartado 94, 7000-554, Évora, Portugal.
| | - Luis M Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
| | - Gema Álvarez-García
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
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12
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Metabolic signatures of Besnoitia besnoiti-infected endothelial host cells and blockage of key metabolic pathways indicate high glycolytic and glutaminolytic needs of the parasite. Parasitol Res 2016; 115:2023-34. [PMID: 26852124 DOI: 10.1007/s00436-016-4946-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 01/29/2016] [Indexed: 10/22/2022]
Abstract
Besnoitia besnoiti is an obligate intracellular and emerging coccidian parasite of cattle with a significant economic impact on cattle industry. During acute infection, fast-proliferating tachyzoites are continuously formed mainly in endothelial host cells of infected animals. Given that offspring formation is a highly energy and cell building block demanding process, the parasite needs to exploit host cellular metabolism to meet its metabolic demands. Here, we analyzed the metabolic signatures of B. besnoiti-infected endothelial host cells and aimed to influence parasite proliferation by inhibitors of specific metabolic pathways. The following inhibitors were tested: fluoro 2-deoxy-D-glucose and 2-deoxy-D-glucose (FDG, DG; inhibitors of glycolysis), 6-diazo-5-oxo-L-norleucin (DON; inhibitor of glutaminolysis), dichloroacetate (DCA; inhibitor of pyruvate dehydrogenase kinase which favorites channeling of glucose carbons into the TCA cycle) and adenosine-monophosphate (AMP; inhibitor of ribose 5-P synthesis). Overall, B. besnoiti infections of bovine endothelial cells induced a significant and infection rate-dependent increase of glucose, lactate, glutamine, glutamate, pyruvate, alanine, and serine conversion rates which together indicate a parasite-triggered up-regulation of glycolysis and glutaminolysis. Thus, addition of DON, FDG, and DG into the cultivation medium of B. besnoiti infected endothelial cells led to a dose-dependent inhibition of parasite replication (4 μM DON, 99.5 % inhibition; 2 mM FDG, 99.1 % inhibition; 2 mM DG, 93 % inhibition; and 8 mM DCA, 71.9 % inhibition). In contrast, AMP had no significant effects on total tachyzoite production up to a concentration of 20 mM. Together, these data may open new strategies for the development of therapeutics for B. besnoiti infections.
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13
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Liu ZY, Wenzler T, Brun R, Zhu X, Boykin DW. Synthesis and antiparasitic activity of new bis-arylimidamides: DB766 analogs modified in the terminal groups. Eur J Med Chem 2014; 83:167-73. [DOI: 10.1016/j.ejmech.2014.06.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 06/06/2014] [Accepted: 06/11/2014] [Indexed: 01/12/2023]
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14
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A review on bovine besnoitiosis: a disease with economic impact in herd health management, caused by Besnoitia besnoiti (Franco and Borges, ). Parasitology 2014; 141:1406-17. [PMID: 24694568 DOI: 10.1017/s0031182014000262] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Bovine besnoitiosis is caused by the largely unexplored apicomplexan parasite Besnoitia besnoiti. In cows, infection during pregnancy often results in abortion, and chronically infected bulls become infertile. Similar to other apicomplexans B. besnoiti has acquired a largely intracellular lifestyle, but its complete life cycle is still unknown, modes of transmission have not been entirely resolved and the definitive host has not been identified. Outbreaks of bovine besnoitiosis in cattle were described in the 1990s in Portugal and Spain, and later several cases were also detected in France. More cases have been reported recently in hitherto unaffected countries, including Italy, Germany, Switzerland, Hungary and Croatia. To date, there is still no effective pharmaceutical compound available for the treatment of besnoitiosis in cattle, and progress in the identification of novel targets for intervention through pharmacological or immunological means is hampered by the lack of molecular data on the genomic and transcriptomic level. In addition, the lack of an appropriate small animal laboratory model, and wide gaps in our knowledge on the host-parasite interplay during the life cycle of this parasite, renders vaccine and drug development a cost- and labour-intensive undertaking.
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15
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Alvarez-García G, Frey CF, Mora LMO, Schares G. A century of bovine besnoitiosis: an unknown disease re-emerging in Europe. Trends Parasitol 2013; 29:407-15. [PMID: 23830145 DOI: 10.1016/j.pt.2013.06.002] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 05/27/2013] [Accepted: 06/04/2013] [Indexed: 10/26/2022]
Abstract
Bovine besnoitiosis, which is caused by the cyst-forming apicomplexan parasite Besnoitia besnoiti, is a chronic and debilitating vector-borne disease characterized by both cutaneous and systemic manifestations. In Europe, this parasitic disease appeared in a few restricted areas in France and Portugal since the first recorded cases in the beginning of the 20th century. However, at present, the disease is considered to be re-emerging by the European Food Safety Authority due to an increased number of cases and the geographic expansion of besnoitiosis into cattle herds in several European countries. In this review, we will provide an update of the epidemiology and impact of B. besnoiti infection. Strategies to control this parasitic disease will also be discussed.
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Affiliation(s)
- Gema Alvarez-García
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain.
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16
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Novel amidines and analogues as promising agents against intracellular parasites: a systematic review. Parasitology 2013; 140:929-51. [PMID: 23561006 DOI: 10.1017/s0031182013000292] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Parasitic protozoa comprise diverse aetiological agents responsible for important diseases in humans and animals including sleeping sickness, Chagas disease, leishmaniasis, malaria, toxoplasmosis and others. They are major causes of mortality and morbidity in tropical and subtropical countries, and are also responsible for important economic losses. However, up to now, for most of these parasitic diseases, effective vaccines are lacking and the approved chemotherapeutic compounds present high toxicity, increasing resistance, limited efficacy and require long periods of treatment. Many of these parasitic illnesses predominantly affect low-income populations of developing countries for which new pharmaceutical alternatives are urgently needed. Thus, very low research funding is available. Amidine-containing compounds such as pentamidine are DNA minor groove binders with a broad spectrum of activities against human and veterinary pathogens. Due to their promising microbicidal activity but their rather poor bioavailability and high toxicity, many analogues and derivatives, including pro-drugs, have been synthesized and screened in vitro and in vivo in order to improve their selectivity and pharmacological properties. This review summarizes the knowledge on amidines and analogues with respect to their synthesis, pharmacological profile, mechanistic and biological effects upon a range of intracellular protozoan parasites. The bulk of these data may contribute to the future design and structure optimization of new aromatic dicationic compounds as novel antiparasitic drug candidates.
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17
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Müller J, Hemphill A. In vitro culture systems for the study of apicomplexan parasites in farm animals. Int J Parasitol 2012; 43:115-24. [PMID: 23000674 DOI: 10.1016/j.ijpara.2012.08.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 08/08/2012] [Accepted: 08/14/2012] [Indexed: 01/02/2023]
Abstract
In vitro culture systems represent powerful tools for the study of apicomplexan parasites such as Cryptosporidium, Eimeria, Sarcocystis, Neospora, Toxoplasma, Besnoitia, Babesia and Theileria, all with high relevance for farm animals. Proliferative stages of these parasites have been cultured in vitro employing a large variety of cell culture and explant approaches. For some, such as Cryptosporidium and Eimeria, the sexual development has been reproduced in cell cultures, while for others, animal experimentation is required to fulfill the life cycle. In vitro cultures have paved the way to exploit the basic biology of these organisms, and had a major impact on the development of tools for diagnostic purposes. With the aid of in vitro cultivation, studies on host-parasite interactions, on factors involved in innate resistance, stage conversion and differentiation, genetics and transfection technology, vaccine candidates and drug effectiveness could be carried out. The use of transgenic parasites has facilitated high-throughput screening of anti-microbial compounds that are active against the proliferative stages. Here, we review the basic features of cell culture-based in vitro systems for apicomplexan parasites that are relevant for farm animals, and discuss their applications with a focus on drug identification and studies of stage differentiation.
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Affiliation(s)
- Joachim Müller
- Institute of Parasitology, Vetsuisse Faculty, University of Berne, Länggass-Strasse 122, CH-3012 Berne, Switzerland.
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18
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Schorer M, Debache K, Barna F, Monney T, Müller J, Boykin DW, Stephens CE, Hemphill A. Di-cationic arylimidamides act against Neospora caninum tachyzoites by interference in membrane structure and nucleolar integrity and are active against challenge infection in mice. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2012; 2:109-20. [PMID: 24533272 DOI: 10.1016/j.ijpddr.2012.03.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 03/19/2012] [Accepted: 03/20/2012] [Indexed: 01/21/2023]
Abstract
Neospora caninum is considered to be the main cause of bovine abortion in Europe and the USA, leading to considerable financial impact. Losses are caused directly by abortions or indirectly through breeding of calves with impaired viability. Due to the lack of effective chemotherapy against bovine neosporosis, there is a need to develop new anti-protozoal compounds, which would either eliminate the parasite or avoid its transmission. In order to identify compounds of interest, the in vitro activities of 41 di-cationic pentamidine derivatives were studied employing a transgenic N. caninum clone expressing beta-galactosidase as a reporter gene. The arylimidamide DB745, previously shown to be highly active against Leishmania donovani in vitro and in vivo, appeared as the most promising compound, with an IC50 of 80 nM in 3-day growth assays and severely affecting both host cell invasion as well as intracellular proliferation. TEM of intracellular tachyzoites identified distinct alterations related to the nucleolus and the nuclear and cellular membrane. Long-term growth assays showed that DB745 acted parasiticidal upon the Nc-Liv isolate, but not against the Nc-1 isolate of N. caninum. In vivo studies in N. caninum (Nc-1 isolate) infected mice showed that daily intraperitoneal application of DB745 for a period of 14 days resulted in a decreased number of clinically affected animals, and lower cerebral parasite burdens in DB745-treated mice compared to non-treated mice. These results illustrate the potential of dicationic arylimidamides for the treatment of N. caninum infections.
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Affiliation(s)
- Michelle Schorer
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Berne, Länggassstrasse 122, CH-3012 Bern, Switzerland
| | - Karim Debache
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Berne, Länggassstrasse 122, CH-3012 Bern, Switzerland
| | - Fabienne Barna
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Berne, Länggassstrasse 122, CH-3012 Bern, Switzerland
| | - Thierry Monney
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Berne, Länggassstrasse 122, CH-3012 Bern, Switzerland
| | - Joachim Müller
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Berne, Länggassstrasse 122, CH-3012 Bern, Switzerland
| | - David W Boykin
- Department of Chemistry, Georgia State University, P.O. Box 4098, Atlanta, GA 30302-4098, USA
| | - Chad E Stephens
- Department of Chemistry and Physics, Augusta State University, Augusta, GA 30904-2200, USA
| | - Andrew Hemphill
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Berne, Länggassstrasse 122, CH-3012 Bern, Switzerland
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da Silva CF, Batista DDGJ, Oliveira GM, de Souza EM, Hammer ER, da Silva PB, Daliry A, Araujo JS, Britto C, Rodrigues ACM, Liu Z, Farahat AA, Kumar A, Boykin DW, de Nazaré Correia Soeiro M. In vitro and in vivo investigation of the efficacy of arylimidamide DB1831 and its mesylated salt form--DB1965--against Trypanosoma cruzi infection. PLoS One 2012; 7:e30356. [PMID: 22291940 PMCID: PMC3264605 DOI: 10.1371/journal.pone.0030356] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 12/14/2011] [Indexed: 11/19/2022] Open
Abstract
Chagas disease is caused by infection with the intracellular protozoan parasite Trypanosoma cruzi. At present, nifurtimox and benznidazole, both compounds developed empirically over four decades ago, represent the chemotherapeutic arsenal for treating this highly neglected disease. However, both drugs present variable efficacy depending on the geographical area and the occurrence of natural resistance, and are poorly effective against the later chronic stage. As a part of a search for new therapeutic opportunities to treat chagasic patients, pre-clinical studies were performed to characterize the activity of a novel arylimidamide (AIA--DB1831 (hydrochloride salt) and DB1965 (mesylate salt)) against T. cruzi. These AIAs displayed a high trypanocidal effect in vitro against both relevant forms in mammalian hosts, exhibiting a high selectivity index and a very high efficacy (IC(50) value/48 h of 5-40 nM) against intracellular parasites. DB1965 shows high activity in vivo in acute experimental models (mouse) of T. cruzi, showing a similar effect to benznidazole (Bz) when compared under a scheme of 10 daily consecutive doses with 12.5 mg/kg. Although no parasitological cure was observed after treating with 20 daily consecutive doses, a combined dosage of DB1965 (5 mg/kg) with Bz (50 mg/kg) resulted in parasitaemia clearance and 100% animal survival. In summary, our present data confirmed that aryimidamides represent promising new chemical entities against T. cruzi in therapeutic schemes using the AIA alone or in combination with other drugs, like benznidazole.
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Affiliation(s)
- Cristiane França da Silva
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | | | - Gabriel Melo Oliveira
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | - Elen Mello de Souza
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | - Erica Ripoll Hammer
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | | | - Anissa Daliry
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | - Julianna Siciliano Araujo
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | - Constança Britto
- Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | - Ana Carolina Mondaine Rodrigues
- Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | - Zongying Liu
- Department of Chemistry, Georgia State University, Atlanta, Georgia, United States of America
| | - Abdelbasset A. Farahat
- Department of Chemistry, Georgia State University, Atlanta, Georgia, United States of America
| | - Arvind Kumar
- Department of Chemistry, Georgia State University, Atlanta, Georgia, United States of America
| | - David W. Boykin
- Department of Chemistry, Georgia State University, Atlanta, Georgia, United States of America
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The adaptive potential of a survival artist: characterization of the in vitro interactions of Toxoplasma gondii tachyzoites with di-cationic compounds in human fibroblast cell cultures. Parasitology 2011; 139:208-20. [PMID: 22011664 DOI: 10.1017/s0031182011001776] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The impact of di-cationic pentamidine-analogues against Toxoplama gondii (Rh- and Me49-background) was investigated. The 72 h-growth assays showed that the arylimidamide DB750 inhibited the proliferation of tachyzoites of T. gondii Rh and T. gondii Me49 with an IC(50) of 0·11 and 0·13 μM, respectively. Pre-incubation of fibroblast monolayers with 1 μM DB750 for 12 h and subsequent culture in the absence of the drug also resulted in a pronounced inhibiton of parasite proliferation. However, upon 5-6 days of drug exposure, T. gondii tachyzoites adapted to the compound and resumed proliferation up to a concentration of 1·2 μM. Out of a set of 32 di-cationic compounds screened for in vitro activity against T. gondii, the arylimidamide DB745, exhibiting an IC(50) of 0·03 μM and favourable selective toxicity was chosen for further studies. DB745 also inhibited the proliferation of DB750-adapted T. gondii (IC(50)=0·07 μM). In contrast to DB750, DB745 also had a profound negative impact on extracellular non-adapted T. gondii tachyzoites, but not on DB750-adapted T. gondii. Adaptation of T. gondii to DB745 (up to a concentration of 0·46 μM) was much more difficult to achieve and feasible only over a period of 110 days. In cultures infected with DB750-adapted T. gondii seemingly intact parasites could occasionally be detected by TEM. This illustrates the astonishing capacity of T. gondii tachyzoites to adapt to environmental changes, at least under in vitro conditions, and suggests that DB745 could be an interesting drug candidate for further assessments in appropriate in vivo models.
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In vitro efficacy of dicationic compounds and mefloquine enantiomers against Echinococcus multilocularis metacestodes. Antimicrob Agents Chemother 2011; 55:4866-72. [PMID: 21768518 DOI: 10.1128/aac.00478-11] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The current chemotherapy of alveolar echinococcosis (AE) is based on benzimidazoles such as albendazole and has been shown to be parasitostatic rather than parasiticidal, requiring lifelong duration. Thus, new and more efficient treatment options are urgently needed. By employing a recently validated assay based on the release of functional phosphoglucose isomerase (PGI) from dying parasites, the activities of 26 dicationic compounds and of the (+)- and (-)-erythro-enantiomers of mefloquine were investigated. Initial screening of compounds was performed at 40 μM, and those compounds exhibiting considerable antiparasitic activities were also assessed at lower concentrations. Of the dicationic drugs, DB1127 (a diguanidino compound) with activities comparable to nitazoxanide was further studied. The activity of DB1127 was dose dependent and led to severe structural alterations, as visualized by electron microscopy. The (+)- and (-)-erythro-enantiomers of mefloquine showed similar dose-dependent effects, although higher concentrations of these compounds than of DB1127 were required for metacestode damage. In conclusion, of the drugs investigated here, the diguanidino compound DB1127 represents the most promising compound for further study in appropriate in vivo models for Echinococcus multilocularis infection.
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