Unlocking the in vitro anti-Trypanosoma cruzi activity of halophyte plants from the southern Portugal

Objective: To evaluate the in vitro anti-Trypanosoma cruzi (T. cruzi) activity of organic extracts prepared from halophyte species collected in the southern coast of Portugal (Algarve), and chemically characterize the most active samples.Methods: Acetone, dichloromethane and methanol extracts were prepared from 31 halophyte species and tested in vitro against trypomastigotes and intracellular amastigotes of the Tulahuen strain of T. cruzi. The most active extract was fractionated by preparative HPLC-DAD, affording 11 fractions. The most selective fraction was fully characterized by H-1 NMR.Results: From 94 samples tested, one was active, namely the root dichloromethane extract of Juncus acutus (IC50 < 20 mu g/mL). This extract was fractionated by HPLC, affording 11 fractions, one of them containing only a pure compound (juncunol), and tested for anti-parasitic activity. Fraction 8 (IC50 = 4.1 mu g/mL) was the most active, and was further characterized by H-1 NMR. The major compounds were phenanthrenes, 9,10-dihydrophenanthrenes and benzocoumarins.Conclusion: Our results suggest that the compounds identified in fraction 8 are likely responsible for the observed anti parasitic activity. Further research is in progress aiming to isolate and identify the specific active molecules. To the best of our knowledge, this is the first report on the in vitro anti T. cruzi activity of halophyte species.PROEP/CNPq/FIOCRUZ 401988/2012-0; FCT/CAPES 2358, 2014/201

Experimental and Clinical Treatment of Chagas Disease : A Review

Altres ajuts: This study was supported by the European Comission under the Health Innovation Work Program of the 7th Framework Program and by CAPES/Brasil, Programa Ciencia Sem Fronteiras and Professor ˆ Visitante Nacional Senior. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The authors have no conflict of interests.Chagas disease (CD) is caused by the protozoan parasite Trypanosoma cruzi that infects a broad range of triatomines and mammalian species, including man. It afflicts 8 million people in Latin America, and its incidence is increasing in nonendemic countries owing to rising international immigration and nonvectorial transmission routes such as blood donation. Since the 1960s, the only drugs available for the clinical treatment of this infection have been benznidazole (BZ) and nifurtimox (NFX). Treatment with these trypanocidal drugs is recommended in both the acute and chronic phases of CD. These drugs have low cure rates mainly during the chronic phase, in addition both drugs present side effects that may result in the interruption of the treatment. Thus, more efficient and better-tolerated new drugs or pharmaceutical formulations containing BZ or NFX are urgently needed. Here, we review the drugs currently used for CD chemotherapy, ongoing clinical assays, and most-promising new experimental drugs. In addition, the mechanism of action of the commercially available drugs, NFX and BZ, the biodistribution of the latter, and the potential for novel formulations of BZ based on nanotechnology are discussed. Taken together, the literature emphasizes the urgent need for new therapies for acute and chronic CD

Molecular characterization of Cyclophilin (TcCyP19) in Trypanosoma cruzi populations susceptible and resistant to benznidazole

Cyclophilin (TcCyP19), a peptidyl-prolyl cis/trans isomerase, is a key molecule with diverse biological functions that include roles in molecular chaperoning, stress response, immune modulation, and signal transduction. In this respect, TcCyP19 could serve as a potential drug target in diseasecausing parasites. Previous studies employing proteomics techniques have shown that the TcCyP19 isoform was more abundant in a benznidazole (BZ)-resistant Trypanosoma cruzi population than in its susceptible counterpart. In this study, TcCyP19 has been characterized in BZ-susceptible and BZresistant T. cruzi populations. Phylogenetic analysis revealed a clear dichotomy between Cyphophilin A (CyPA) sequences from trypanosomatids and mammals. Sequencing analysis revealed that the amino acid sequences of TcCyP19 were identical among the T. cruzi samples analyzed. Southern blot analysis showed that TcCyP19 is a single-copy gene, located in chromosomal bands varying in size from 0.68 to 2.2 Mb, depending on the strain of T. cruzi. Northern blot and qPCR indicated that the levels of TcCyP19 mRNA were two-fold higher in drug-resistant T. cruzi populations than in their drugsusceptible counterparts. Similarly, as determined by two-dimensional gel electrophoresis immunoblot, the expression of TcCyP19 protein was increased to the same degree in BZ-resistant T. cruzi populations. No differences in TcCyP19 mRNA and protein expression levels were observed between the susceptible and the naturally resistant T. cruzi strains analyzed. Taken together, these data indicate that cyclophilin TcCyP19 expression is up-regulated at both transcriptional and translational levels in T. cruzi populations that were in vitro-induced and in vivo-selected for resistance to BZ.Fil: Rêgo, Juciane Vaz. Universidade Federal Do Piaui.; BrasilFil: Duarte, Ana Paula. Fundación Oswaldo Cruz; BrasilFil: Liarte, Daniel Barbosa. Universidade Federal Do Piaui.; BrasilFil: de Carvalho Sousa, Francirlene. Universidade Federal Do Piaui.; BrasilFil: Barreto, Humberto Medeiros. Universidade Federal Do Piaui.; BrasilFil: Bua, Jacqueline Elena. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben”; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Romanha, Alvaro José. Fundación Oswaldo Cruz; BrasilFil: Rádis Baptista, Gandhi. Universidade Federal Do Piaui.; BrasilFil: Murta, Silvane Maria Fonseca. Universidade Federal Do Piaui.; Brasi

Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets

Functional analysis of cytosolic tryparedoxin peroxidase in antimony-resistant and –susceptible Leishmania braziliensis and Leishmania infantum Lines

Submitted by Nuzia Santos ([email protected]) on 2015-03-23T19:18:06Z No. of bitstreams: 1 2014_166.pdf: 948597 bytes, checksum: 6877ac166c51b962e86adf57e9c472b4 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2015-03-23T19:18:14Z (GMT) No. of bitstreams: 1 2014_166.pdf: 948597 bytes, checksum: 6877ac166c51b962e86adf57e9c472b4 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2015-03-23T19:20:28Z (GMT) No. of bitstreams: 1 2014_166.pdf: 948597 bytes, checksum: 6877ac166c51b962e86adf57e9c472b4 (MD5)Made available in DSpace on 2015-03-23T19:20:28Z (GMT). No. of bitstreams: 1 2014_166.pdf: 948597 bytes, checksum: 6877ac166c51b962e86adf57e9c472b4 (MD5) Previous issue date: 2014Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brazil.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brazil.BACKGROUND: Tryparedoxin peroxidase (TXNPx) participates in defence against oxidative stress as an antioxidant by metabolizing hydrogen peroxide into water molecules. Reports suggest that drug-resistant parasites may increase the levels of TXNPx and other enzymes, thereby protecting them against oxidative stress. METHODS: In this study, the gene encoding cytosolic TXNPx (cTXNPx) was characterized in lines of Leishmania (Viannia) braziliensis and Leishmania (Leishmania) infantum that are susceptible and resistant to potassium antimony tartrate (Sb(III)). We investigated the levels of mRNA and genomic organization of the cTXNPx gene. In addition, we transfected the Leishmania lines with the cTXNPx gene and analysed the susceptibility of transfected parasites to Sb(III) and to hydrogen peroxide (H2O2). RESULTS: Northern blot and real-time reverse transcriptase polymerase chain reaction analyses revealed that the level of TXNPx mRNA was approximately 2.5-fold higher in the Sb(III)-resistant L. braziliensis line than in the parental line. In contrast, no significant difference in cTXNPx mRNA levels between the L. infantum lines was observed. Southern blot analyses revealed that the cTXNPx gene is not amplified in the genome of the Sb(III)-resistant Leishmania lines analysed. Functional analysis of cTXNPx was performed to determine whether overexpression of the enzyme in L. braziliensis and L. infantum lines would change their susceptibility to Sb(III). Western blotting analysis showed that the level of cTXNPx was 2 to 4-fold higher in transfected clones compared to non-transfected cells. Antimony susceptibility test (EC50 assay) revealed that L. braziliensis lines overexpressing cTXNPx had a 2-fold increase in resistance to Sb(III) when compared to the untransfected parental line. In addition, these clones are more tolerant to exogenous H2O2 than the untransfected parental line. In contrast, no difference in Sb(III) susceptibility and a moderate index of resistance to H2O2 was observed in L. infantum clones overexpressing cTXNPx. CONCLUSION: Our functional analysis revealed that cTXNPx is involved in the antimony-resistance phenotype in L. braziliensis

Involvement of nucleoside diphosphate kinase b and elongation factor 2 in Leishmania braziliensis antimony resistance phenotype

Submitted by Nuzia Santos ([email protected]) on 2017-12-13T17:39:21Z No. of bitstreams: 1 Involvement of nucleoside diphosphate .pdf: 13262803 bytes, checksum: 09bae760f7624e67eb06a2fb6d51fa8b (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2017-12-13T17:44:03Z (GMT) No. of bitstreams: 1 Involvement of nucleoside diphosphate .pdf: 13262803 bytes, checksum: 09bae760f7624e67eb06a2fb6d51fa8b (MD5)Made available in DSpace on 2017-12-13T17:44:03Z (GMT). No. of bitstreams: 1 Involvement of nucleoside diphosphate .pdf: 13262803 bytes, checksum: 09bae760f7624e67eb06a2fb6d51fa8b (MD5) Previous issue date: 2016Fundação Oswaldo Cruz. Instituto René Rachou. Belo Horizonte, MG, BrazilFundação Oswaldo Cruz. Instituto René Rachou. Belo Horizonte, MG, BrazilBackground: Nucleoside diphosphate kinase b (NDKb) is responsible for nucleoside triphosphates synthesis and it has key role in the purine metabolism in trypanosomatid protozoans. Elongation factor 2 (EF2) is an important factor for protein synthesis. Recently, our phosphoproteomic analysis demonstrated that NDKb and EF2 proteins were phosphorylated and dephosphorylated in antimony (SbIII)-resistant L. braziliensis line compared to its SbIII-susceptible pair, respectively. Methods; In this study, the overexpression of NDKb and EF2 genes in L. braziliensis and L. infantum was performed to investigate the contribution of these proteins in the SbIII-resistance phenotype. Furthermore, we examined the role of lamivudine on SbIII susceptibility in clones that overexpress the NDKb gene, and the effect of EF2 kinase (EF2K) inhibitor on the growth of EF2-overexpressing parasites. Results: Western blot analysis demonstrated that NDKb and EF2 proteins are more and less expressed, respectively, in SbIII-resistant line of L. braziliensis than its wild-type (WTS) counterpart, corroborating our previous phosphoproteomic data. NDKb or EF2-overexpressing L. braziliensis lines were 1.6 to 2.1-fold more resistant to SbIII than the untransfected WTS line. In contrast, no difference in SbIII susceptibility was observed in L. infantum parasites overexpressing NDKb or EF2. Susceptibility assays showed that NDKb-overexpressing L. braziliensis lines presented elevated resistance to lamivudine, an antiviral agent, but it did not alter the leishmanicidal activity in association with SbIII. EF2-overexpressing L. braziliensis clone was slightly more resistant to EF2K inhibitor than the WTS line. Surprisingly, this inhibitor increased the antileishmanial effect of SbIII, suggesting that this association might be a valuable strategy for leishmaniasis chemotherapy. Conclusion: Our findings represent the first study of NDKb and EF2 genes overexpression that demonstrates an increase of SbIII resistance in L. braziliensis which can contribute to develop new strategies for leishmaniasis treatment

Desenho in silico de sgRNAs e donor DNAs para deleção de enzimas relacionadas ao fenótipo de resistência do Trypanosoma cruzi ao benzonidazol

A doença de Chagas, causada pelo protozoário Trypanosoma cruzi, afeta milhões de pessoas, principalmente na América Latina. Seu tratamento é baseado no uso clínico do benzonidazol (BZ) ou nifurtimox e possui limitações, como baixa eficácia de cura principalmente na fase crônica da doença e ocorrência de parasitos resistentes a ambos compostos. Várias enzimas têm sido relacionadas com o fenótipo de resistência dos parasitos a esses fármacos, tais como a nitroredutase 1, a aldo‐keto redutase e a álcool desidrogenase. A fim de melhor compreender o papel dessas enzimas no fenótipo de resistência do T. cruzi ao BZ, propomos utilizar o CRISPR/Cas9 para realizar a deleção dessas enzimas. Foram realizadas análises in silico para o desenho dos sgRNAs e donor DNAs por meio da avaliação do número de cópias de cada gene na cepa CL Brener usando o tBLASTn, a construção dos sgRNAs e dos donor DNAs pela ferramenta EuPaGDT e o alinhamento global das cópias pelo Needle (EMBOSS). Foram encontradas duas sequências do gene NTR-1, duas para a ADH e pelomenos nove para a AKR, sendo escolhidos três sgRNAs para reconhecimento específico de cada uma das cópias. Devido às características dos sgRNAs selecionados e eficiência do protocolo de CRISPR/Cas9, acreditamos que será possível realizar a deleção dos genes NTR-1 e ADH na cepa CL Brener de T. cruzi utilizando essa metodologia caso não sejam genes essenciais para o parasito. Já no caso da AKR mais análises serão necessárias para conhecer o número exato de cópias do gene.Palavras-chave: Trypanosoma cruzi. Resistência ao benzonidazol. CRISPR/Cas9. Deleção gênica.   

Ascorbate peroxidase overexpression protects Leishmania braziliensis against trivalent antimony effects

Ascorbate peroxidase (APX) is a redox enzyme of the trypanothione pathway that converts hydrogen peroxide (H2O2) into water molecules. In the present study, the APX gene was overexpressed in Leishmania braziliensis to investigate its contribution to the trivalent antimony (SbIII)-resistance phenotype. Western blot results demonstrated that APX-overexpressing parasites had higher APX protein levels in comparison with the wild-type line (LbWTS). APX-overexpressing clones showed an 8-fold increase in the antimony-resistance index over the parental line. In addition, our results indicated that these clones were approximately 1.8-fold more tolerant to H2O2 than the LbWTS line, suggesting that the APX enzyme plays an important role in the defence against oxidative stress. Susceptibility tests revealed that APX-overexpressing L. braziliensis lines were more resistant to isoniazid, an antibacterial agent that interacts with APX. Interestingly, this compound enhanced the anti-leishmanial SbIII effect, indicating that this combination represents a good strategy for leishmaniasis chemotherapy. Our data demonstrate that APX enzyme is involved in the development of L. braziliensis antimony-resistance phenotype and may be an attractive therapeutic target in the design of new strategies for leishmaniasis treatment