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van den Bogaart E, Schoone GJ, Adams ER, Schallig HDFH. Duplex quantitative Reverse-Transcriptase PCR for simultaneous assessment of drug activity against Leishmania intracellular amastigotes and their host cells. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2013; 4:14-9. [PMID: 24596664 PMCID: PMC3940078 DOI: 10.1016/j.ijpddr.2013.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 11/06/2013] [Accepted: 11/07/2013] [Indexed: 12/01/2022]
Abstract
A duplex qRT-PCR was optimized for use in drug screening against Leishmania. Drug activities were measured against the intracellular amastigote stage. Cytotoxicity against the human host cells was simultaneously assessed. Consistent and reproducible dose–response data were generated. Suitability of this duplex PCR for anti-leishmanial drug screening was demonstrated.
Currently available drugs for treatment of Leishmania infections are highly toxic and drug resistance to first line therapies has been observed. New, safer and more effective drugs are urgently needed to improve clinical resolution of the disease and reduce the risks associated with it. High-throughput screening of new compounds against cultured promastigotes is easy to perform, but the results are poorly predictive of in vivo efficacy. Intra-macrophage amastigote models provide a better proxy of the clinically relevant stage of disease and should be routinely implemented in the search for new anti-leishmanial agents, despite being labor intensive. This study describes the use of a duplex quantitative Reverse-Transcriptase PCR (qRT-PCR) for assessment of drug activity against Leishmania intracellular amastigotes and their host cells. The assay simultaneously quantifies Leishmania 18S ribosomal RNA and the human β2-microglobulin (β-2M) mRNA, used for monitoring drug cytotoxicity and test performance. Accurate determination of parasite viability by the newly developed qRT-PCR was confirmed by parallel assessment of compound performance against standard microscopy. Highly reproducible anti-leishmanial activities were obtained with a set of structurally- and pharmacologically-diverse compounds, whose toxicity against host cells correlated with a low β-2M amplification. Sensitive and versatile, this duplex qRT-PCR offers a valuable tool for assessment of drug activities against Leishmania amastigotes and their host cells.
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Affiliation(s)
- Erika van den Bogaart
- Royal Tropical Institute (KIT), Department of Biomedical Research, Parasitology Unit, Meibergdreef 39, Amsterdam 1105 AZ, The Netherlands
| | - Gerard J Schoone
- Royal Tropical Institute (KIT), Department of Biomedical Research, Parasitology Unit, Meibergdreef 39, Amsterdam 1105 AZ, The Netherlands
| | - Emily R Adams
- Royal Tropical Institute (KIT), Department of Biomedical Research, Parasitology Unit, Meibergdreef 39, Amsterdam 1105 AZ, The Netherlands
| | - Henk D F H Schallig
- Royal Tropical Institute (KIT), Department of Biomedical Research, Parasitology Unit, Meibergdreef 39, Amsterdam 1105 AZ, The Netherlands
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Evaluation of reference genes for quantitative real-time RT-PCR analysis of gene expression in Nile tilapia (Oreochromis niloticus). Gene 2013; 527:183-92. [PMID: 23792389 DOI: 10.1016/j.gene.2013.06.013] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 05/29/2013] [Accepted: 06/07/2013] [Indexed: 11/20/2022]
Abstract
Quantitative real-time reverse-transcriptase polymerase chain reaction (RT-qPCR) has been used frequently to study gene expression related to fish immunology. In such studies, a stable reference gene should be selected to correct the expression of the target gene. In this study, seven candidate reference genes (glyceraldehyde-3-phosphate dehydrogenase (GADPH), ubiquitin-conjugating enzyme (UBCE), 18S ribosomal RNA (18S rRNA), beta-2-microglobulin (B2M), elongation factor 1 alpha (EF1A), tubulin alpha chain-like (TUBA) and beta actin (ACTB)), were selected to analyze their stability and normalization in seven tissues (liver, spleen, kidney, brain, heart, muscle and intestine) of Nile tilapia (Oreochromis niloticus) challenged with Streptococcus agalactiae or Streptococcus iniae, respectively. The results showed that all the candidate reference genes exhibited tissue-dependent transcriptional variations. With PBS injection as a control, UBCE was the most stable and suitable single reference gene in the intestine, liver, brain, kidney, and spleen after S. iniae infection, and in the liver, kidney, and spleen after S. agalactiae infection. EF1A was the most suitable in heart and muscle after S. iniae or S. agalactiae infection. GADPH was the most suitable gene in intestine and brain after S. agalactiae infection. In normal conditions, UBCE and 18S rRNA were the most stably expressed genes across the various tissues. These results showed that for RT-qPCR analysis of tilapia, selecting two or more reference genes may be more suitable for cross-tissue analysis of gene expression.
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Real-time PCR assay for detection and quantification of Leishmania (Viannia) organisms in skin and mucosal lesions: exploratory study of parasite load and clinical parameters. J Clin Microbiol 2013; 51:1826-33. [PMID: 23554201 DOI: 10.1128/jcm.00208-13] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Earlier histopathology studies suggest that parasite loads may differ between cutaneous leishmaniasis (CL) and mucosal leishmaniasis (ML) lesions and between acute and chronic CL. Formal demonstration requires highly sensitive detection and accurate quantification of Leishmania in human lesional tissue. In this study, we developed a quantitative real-time PCR (qPCR) assay targeting minicircle kinetoplast DNA (kDNA) to detect and quantify Leishmania (Viannia) parasites. We evaluated a total of 156 lesion biopsy specimens from CL or ML suspected cases and compared the quantitative performance of our kDNA qPCR assay with that of a previously validated qPCR assay based on the glucose-6-phosphate dehydrogenase (G6PD) gene. We also examined the relationship between parasite load and clinical parameters. The kDNA qPCR sensitivity for Leishmania detection was 97.9%, and its specificity was 87.5%. The parasite loads quantified by kDNA qPCR and G6PD qPCR assays were highly correlated (r = 0.87; P < 0.0001), but the former showed higher sensitivity (P = 0.000). CL lesions had 10-fold-higher parasite loads than ML lesions (P = 0.009). Among CL patients, the parasite load was inversely correlated with disease duration (P = 0.004), but there was no difference in parasite load according to the parasite species, the patient's age, and number or area of lesions. Our findings confirm that CL and recent onset of disease (<3 months) are associated with a high parasite load. Our kDNA qPCR assay proved highly sensitive and accurate for the detection and quantification of Leishmania (Viannia) spp. in lesion biopsy specimens. It has potential application as a diagnostic and follow-up tool in American tegumentary leishmaniasis.
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Cruz I, Millet A, Carrillo E, Chenik M, Salotra P, Verma S, Veland N, Jara M, Adaui V, Castrillón C, Arévalo J, Moreno J, Cañavate C. An approach for interlaboratory comparison of conventional and real-time PCR assays for diagnosis of human leishmaniasis. Exp Parasitol 2013; 134:281-9. [PMID: 23562705 DOI: 10.1016/j.exppara.2013.03.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 02/12/2013] [Accepted: 03/04/2013] [Indexed: 11/19/2022]
Abstract
Protozoa of the Leishmania genus are transmitted to humans by the bite of infected sandflies, and are the causative agents of leishmaniasis which ranges from cutaneous to visceral clinical forms. The definitive diagnosis of leishmaniasis has relied traditionally on parasite demonstration, either by microscopy or culture; in the last years, diagnosis based on PCR methods has overcome some drawbacks of traditional methods, increasing sensitivity and allowing using less invasive sampling for diagnosis. However, there are not defined protocols and almost each laboratory applies its own in-house method. Although there are several studies comparing the performance of different methods within the same laboratory, those addressing interlaboratory comparison are scarce, in spite of the growing number of collaborative projects between partners from different leishmaniasis endemic and non-endemic countries. In this work we propose a protocol for interlaboratory comparison of conventional and real-time PCR methods involving four participant laboratories from four different endemic regions in four continents; the protocol includes a quality control step and reduces the variability among the samples tested by each participant. A panel of 77 samples from human origin and 9 from different parasite strains was blindly tested by the participants, aiming to assess the sensitivity of the different methods as well as their usefulness for species identification. Real-time PCR methods targeting the kDNA minicircles returned the highest sensitivity, while both PCR targeting ITS-1 and further HaeIII digestion and a combined algorithm including hsp70 PCR and restriction fragment length polymorphism analysis were the most appropriate approaches for species identification.
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Affiliation(s)
- Israel Cruz
- WHO Collaborating Center for Leishmaniasis, Servicio de Parasitología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Ctra. Majadahonda-Pozuelo, Km2, 28220 Madrid, Spain.
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Pourabbas B, Ghadimi Moghadam A, Pouladfar G, Rezaee Z, Alborzi A. Quantification of Leishmania infantum kinetoplast DNA for monitoring the response to meglumine antimoniate therapy in visceral leishmaniasis. Am J Trop Med Hyg 2013; 88:868-71. [PMID: 23400573 DOI: 10.4269/ajtmh.12-0440] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Meglumine antimoniate (Glucantime) remains the therapeutic cornerstone of visceral leishmaniasis (VL). Twenty-one VL patients were treated with Glucantime, extending for 1 week after defervescence. For monitoring the response, Leishmania infantum kinetoplast DNA loads were evaluated using real-time polymerase chain reaction (PCR) assay in the blood. The maximum duration of treatment was 14 days. The loads before treatment ranged from 8 to 1,300,000 parasites/mL (mean = 73,095 parasites/mL), and the mean values on days 3, 7, 14, 28, and 90 were 4,902, 506, 6.33, 0.26, and 0.14, respectively. The loads decline to < 1 parasite/mL for 16 (76%) and 20 (95%) patients on days 14 and 28, respectively, and they decline for all patients by day 90. Results showed a dramatic decrease of the parasite loads, although complete clearance was not accomplished at the end of treatment. Only one relapse (4.5%) was observed. The parasite load can also serve as a dependable index for monitoring the response to Glucantime.
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Affiliation(s)
- Bahman Pourabbas
- Professor Alborzi Clinical Microbiology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
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Moreira NDD, Vitoriano-Souza J, Roatt BM, Vieira PMDA, Ker HG, de Oliveira Cardoso JM, Giunchetti RC, Carneiro CM, de Lana M, Reis AB. Parasite burden in hamsters infected with two different strains of leishmania (Leishmania) infantum: "Leishman Donovan units" versus real-time PCR. PLoS One 2012; 7:e47907. [PMID: 23112869 PMCID: PMC3480442 DOI: 10.1371/journal.pone.0047907] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 09/17/2012] [Indexed: 12/04/2022] Open
Abstract
To develop and test new therapeutics and immune prophylaxis strategies for visceral leishmaniasis (VL), understanding tissue parasitism evolution after experimental infection with Leishmania infantum is important. Experimental infection in a hamster model (Mesocricetus auratus) reproduces several typical aspects of canine and human VL that are closely related to the inoculum’s route. We quantified the parasitism in the liver and spleen of hamsters experimentally infected by various routes (intradermal, intraperitoneal, and intracardiac [IC]) and different strains of L. infantum (MHOM/BR/74/PP75 and Wild) and compared two different methodologies to evaluate tissue parasitism (Leishman Donovan units [LDU] and real-time qPCR). In addition, the quantification of specific total-IgG in the serum of uninfected and infected hamsters was determined by ELISA. The animals were followed for 1, 3, 6 and 9 months post-infection for survival analysis. We found that infection with the Wild strain by the IC route resulted in higher mortality. Positive antibody (IgG) responses were detected with higher peaks at 6 and 9 months in the IC group inoculated with PP75 strain. However, in animals infected with the Wild strain the IgG levels were elevated in all infected groups during all the time evaluated. We also observed by LDU analysis that the IC route lead to higher parasitism in the liver and spleen with both strains. Furthermore, qPCR showed higher sensitivity for identifying animals with low parasitic burden. In conclusion, qPCR can be useful for assessing parasitism in the spleen and liver of a hamster model infected with L. infantum independent of the route of infection, and this technique may become an essential tool for assessing parasite density in the hamster model after experimental treatment or immunization with potential vaccine candidates.
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Affiliation(s)
- Nádia das Dores Moreira
- Laboratório de Imunopatologia, Núcleo de Pesquisas em Ciências Biológicas/NUPEB, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
| | - Juliana Vitoriano-Souza
- Laboratório de Imunopatologia, Núcleo de Pesquisas em Ciências Biológicas/NUPEB, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
| | - Bruno Mendes Roatt
- Laboratório de Imunopatologia, Núcleo de Pesquisas em Ciências Biológicas/NUPEB, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
| | - Paula Melo de Abreu Vieira
- Laboratório de Imunopatologia, Núcleo de Pesquisas em Ciências Biológicas/NUPEB, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
| | - Henrique Gama Ker
- Laboratório de Imunopatologia, Núcleo de Pesquisas em Ciências Biológicas/NUPEB, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
| | - Jamille Mirelle de Oliveira Cardoso
- Laboratório de Imunopatologia, Núcleo de Pesquisas em Ciências Biológicas/NUPEB, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
| | - Rodolfo Cordeiro Giunchetti
- Laboratório de Imunopatologia, Núcleo de Pesquisas em Ciências Biológicas/NUPEB, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
| | - Cláudia Martins Carneiro
- Laboratório de Imunopatologia, Núcleo de Pesquisas em Ciências Biológicas/NUPEB, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
- Laboratório de Pesquisas Clínicas, Departamento de Análises Clínicas, Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
| | - Marta de Lana
- Laboratório de Pesquisas Clínicas, Departamento de Análises Clínicas, Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
- Laboratório de Doença de Chagas, Núcleo de Pesquisas em Ciências Biológicas/NUPEB, Departamento de Análises Clínicas, Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
| | - Alexandre Barbosa Reis
- Laboratório de Imunopatologia, Núcleo de Pesquisas em Ciências Biológicas/NUPEB, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
- Laboratório de Pesquisas Clínicas, Departamento de Análises Clínicas, Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil
- * E-mail:
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Gomes LI, Gonzaga FM, Morais-Teixeira ED, de Souza-Lima BS, Freire VV, Rabello A. Validation of quantitative real-time PCR for the in vitro assessment of antileishmanial drug activity. Exp Parasitol 2012; 131:175-9. [DOI: 10.1016/j.exppara.2012.03.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 02/09/2012] [Accepted: 03/19/2012] [Indexed: 11/26/2022]
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Reimão JQ, Colombo FA, Pereira-Chioccola VL, Tempone AG. Effectiveness of liposomal buparvaquone in an experimental hamster model of Leishmania (L.) infantum chagasi. Exp Parasitol 2012; 130:195-9. [PMID: 22281156 DOI: 10.1016/j.exppara.2012.01.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 01/10/2012] [Accepted: 01/11/2012] [Indexed: 11/25/2022]
Abstract
The objective of this study was to develop a novel liposomal formulation, containing phosphatidylserine (PS), of buparvaquone (BPQ) and to evaluate its in vivo effectiveness in Leishmania (L.) infantum chagasi-infected hamsters. The activity of BPQ was evaluated against both the promastigote forms of different Leishmania species and the intracellular amastigotes of L. (L.) infantum chagasi. Buparvaquone was entrapped in PS-liposomes (BPQ-PS-LP), and the drug was quantified by ultra-high-performance liquid chromatography. The treatment was quantified by detecting the RNA of the living amastigotes in the spleen and the liver by real-time PCR. In vitro assays with L. (L.) infantum chagasi intracellular amastigotes were performed in peritoneal macrophages for the evaluation of the 50% inhibitory concentration (IC(50)). BPQ-PS-LP at 0.33 mg/kg/day for eight consecutive days reduced the number of amastigotes by 89.4% (P<0.05) in the spleen and by 67.2% (P>0.05) in the liver, compared to 84.3% (P<0.05) and 99.7% (P<0.05), respectively, following Glucantime® treatment at 50 mg/kg/day. Free BPQ at 20 mg/kg/day failed to treat the hamsters when compared to the untreated group. BPQ was significantly (P<0.05) selective against L. (L.) infantum chagasi intracellular amastigotes, with an IC(50) value of 1.5 μM; no in vitro mammalian cytotoxicity could be detected. Other cutaneous species were also susceptible to BPQ, with IC(50) values in the range 1-4 μM. BPQ-PS-LP caused a significant reduction in the parasite burden at a 60-fold lower dose than did the free BPQ. These results show the potential of PS-liposome formulations for the successful targeted delivery of BPQ in visceral leishmaniasis.
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Affiliation(s)
- Juliana Q Reimão
- Department of Parasitology, Instituto Adolfo Lutz, Avenida Dr. Arnaldo, 351, 8° Andar. Cerqueira César, CEP 01246-902 São Paulo, SP, Brazil
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