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Immunity, Inflammation and Disease Jun 2020In canine visceral leishmaniasis (CVL), lymphopenia, and the disorganization of lymphoid organs such as spleen and lymph nodes have been demonstrated. However, the...
INTRODUCTION
In canine visceral leishmaniasis (CVL), lymphopenia, and the disorganization of lymphoid organs such as spleen and lymph nodes have been demonstrated. However, the involvement of thymus in CVL has not been evaluated so far. Herein, we investigated whether the thymus can be colonized by Leishmania infantum in naturally infected dogs.
METHODS
Thymus were obtained from 16 of 58 dogs and samples of this organ were submitted to immunohistochemistry for laminin and fibronectin detection, histopathology, in situ hybridization and polymerase chain reaction (PCR) targeting the gene ITS-1 for Leishmania and sequenced. Samples of spleen, skin and popliteal lymph nodes were collected and submitted to immunohistochemistry and parasitological culture followed by multilocus enzyme electrophoresis.
RESULTS
L. infantum was identified in all dogs. DNA and amastigote forms of Leishmania were detected in the thymus from 16 dogs by PCR and in eight by immunohistochemistry. Besides thymus, parasites were detected in spleen, lymph nodes, and skin. A granulomatous or pyogranulomatous thymitis was observed in eight dogs associated to intact amastigotes forms of this parasite. Fibronectin deposition in thymus was higher in dogs with more clinical signs.
CONCLUSIONS
These results demonstrate that the thymus of dogs can be parasitized by L. infantum, which may generate inflammatory reactions leading to alterations in thymic microarchitecture.
Topics: Animals; DNA, Protozoan; Dog Diseases; Dogs; Female; Leishmania infantum; Leishmaniasis, Visceral; Lymph Nodes; Male; Parasite Load; Skin; Spleen; Thymus Gland
PubMed: 32207879
DOI: 10.1002/iid3.285 -
Scientific Reports Feb 2020Leishmaniases are neglected tropical diseases and Leishmania (Leishmania) infantum and Leishmania (Viannia) braziliensis are the most important causative agents of...
Leishmaniases are neglected tropical diseases and Leishmania (Leishmania) infantum and Leishmania (Viannia) braziliensis are the most important causative agents of leishmaniases in the New World. These two parasite species may co-circulate in a given endemic area but their interactions in the vector have not been studied yet. We conducted experimental infections using both single infections and co-infections to compare the development of L. (L.) infantum (OGVL/mCherry) and L. (V.) braziliensis (XB29/GFP) in Lutzomyia longipalpis and Lutzomyia migonei. Parasite labelling by different fluorescein proteins enabled studying interspecific competition and localization of different parasite species during co-infections. Both Leishmania species completed their life cycle, producing infective forms in both sand fly species studied. The same happens in the co infections, demonstrating that the two parasites conclude their development and do not compete with each other. However, infections produced by L. (L.) infantum reached higher rates and grew more vigorously, as compared to L. (V.) braziliensis. In late-stage infections, L. (L.) infantum was present in all midgut regions, showing typical suprapylarian type of development, whereas L. (V.) braziliensis was concentrated in the hindgut and the abdominal midgut (peripylarian development). We concluded that both Lu. migonei and Lu. longipalpis are equally susceptible vectors for L. (L.) infantum, in laboratory colonies. In relation to L. (V.) braziliensis, Lu. migonei appears to be more susceptible to this parasite than Lu. longipalpis.
Topics: Animals; Digestive System; Female; Insect Vectors; Leishmania braziliensis; Leishmania infantum; Life Cycle Stages; Psychodidae
PubMed: 32108151
DOI: 10.1038/s41598-020-60600-7 -
PloS One 2016Dogs represent the most important domestic reservoir of L. chagasi (syn. L. infantum). A vaccine against canine visceral leishmaniasis (CVL) would be an important tool...
Dogs represent the most important domestic reservoir of L. chagasi (syn. L. infantum). A vaccine against canine visceral leishmaniasis (CVL) would be an important tool for decreasing the anxiety related to possible L. chagasi infection and for controlling human visceral leishmaniasis (VL). Because the sand fly salivary proteins are potent immunogens obligatorily co-deposited during transmission of Leishmania parasites, their inclusion in an anti-Leishmania vaccine has been investigated in past decades. We investigated the immunogenicity of the "LbSapSal" vaccine (L. braziliensis antigens, saponin as adjuvant, and Lutzomyia longipalpis salivary gland extract) in dogs at baseline (T0), during the post-vaccination protocol (T3rd) and after early (T90) and late (T885) times following L. chagasi-challenge. Our major data indicated that immunization with "LbSapSal" is able to induce biomarkers characterized by enhanced amounts of type I (tumor necrosis factor [TNF]-α, interleukin [IL]-12, interferon [IFN]-γ) cytokines and reduction in type II cytokines (IL-4 and TGF-β), even after experimental challenge. The establishment of a prominent pro-inflammatory immune response after "LbSapSal" immunization supported the increased levels of nitric oxide production, favoring a reduction in spleen parasitism (78.9%) and indicating long-lasting protection against L. chagasi infection. In conclusion, these results confirmed the hypothesis that the "LbSapSal" vaccination is a potential tool to control the Leishmania chagasi infection.
Topics: Animals; Biomarkers; Brazil; Cytokines; Dog Diseases; Dogs; Female; Inflammation Mediators; Leishmania infantum; Leishmaniasis Vaccines; Leishmaniasis, Visceral; Leukocytes, Mononuclear; Male; Models, Biological; Nitric Oxide; Parasite Load; Spleen; Vaccination
PubMed: 27556586
DOI: 10.1371/journal.pone.0161169 -
Frontiers in Immunology 2022In this study we explored the previously established leishmanicidal activity of a complementary set of 24 imidazolium salts (IS), 1-hexadecylimidazole (CIm) and...
In this study we explored the previously established leishmanicidal activity of a complementary set of 24 imidazolium salts (IS), 1-hexadecylimidazole (CIm) and 1-hexadecylpyridinium chloride (CPyrCl) against and . Promastigotes of and were incubated with 0.1 to 100 μM of the compounds and eight of them demonstrated leishmanicidal activity after 48 h - CMImMeS (IC = 11.6), CMImPF(IC = 6.9), CMImBr (IC = 6), CMImCl (IC = 4.1), CMImCl (IC = 1.8), (C)MImCl (IC = 1.9), CIm (IC = 14.6), and CPyrCl (IC = 4).The effect of IS on reactive oxygen species production, mitochondrial membrane potential, membrane integrity and morphological alterations of promastigotes was determined, as well as on -infected macrophages. Their cytotoxicity against macrophages and human erythrocytes was also evaluated. The IS CMImMeS, CMImPF, CMImBr, CMImCl, CMImCl and (C)MImCl, and the compounds CIm and CPyrCl killed and inhibited the growth of promastigote forms of and in a concentration-dependent manner, contributing to a better understanding of the structure-activity relationship of IS against . These IS induced ROS production, mitochondrial dysfunction, membrane disruption and morphological alterations in infective forms of and killed intracellular amastigote forms in very low concentrations (IC ≤ 0.3), being potential drug candidates against .
Topics: Animals; Mice; Humans; Salts; Leishmania mexicana; Antiprotozoal Agents; Mice, Inbred BALB C; Leishmania infantum; Oxidative Stress
PubMed: 36733394
DOI: 10.3389/fimmu.2022.1096312 -
Immune response to Leishmania (Leishmania) chagasi infection is reduced in malnourished BALB/c mice.Memorias Do Instituto Oswaldo Cruz Sep 2010Protein-energy malnutrition and micronutrient deficiencies may down-regulate immune response and increase morbidity and mortality due to infection. In this study, a...
Protein-energy malnutrition and micronutrient deficiencies may down-regulate immune response and increase morbidity and mortality due to infection. In this study, a murine model was used to study the effects of protein, iron and zinc deficiencies on the immune response to Leishmania (Leishmania) chagasi infection. Mice were initially fed a standard diet or with a diet containing 3% casein but deficient in zinc and iron. After malnutrition was established, mice were inoculated with L. chagasi and sacrificed four weeks later in order to evaluate liver and spleen parasite loads and serum biochemical parameters. Significant decreases in liver and spleen weight, an increase in the parasite loads in these organs and decreases in serum protein and glucose concentrations in malnourished animals were observed. Furthermore, the production of interferon-gamma by spleen cells from infected malnourished mice stimulated by Leishmania antigen was significantly lower compared with that in control diet mice. These data suggest that malnutrition alters the immune response to L. chagasi infection in the BALB/c model and, in association with the effects on biochemical and anatomical parameters of the host, favored increases in the parasite loads in the spleens and livers of these animals.
Topics: Adaptive Immunity; Animals; Cytokines; Disease Models, Animal; Female; Iron; Iron Deficiencies; Leishmania infantum; Leishmaniasis, Visceral; Liver; Mice; Mice, Inbred BALB C; Nitric Oxide; Protein-Energy Malnutrition; Spleen; Zinc
PubMed: 20944998
DOI: 10.1590/s0074-02762010000600014 -
Genes Jun 2022Parasites of medical importance, such as and are characterized by the presence of thousands of circular DNA molecules forming a structure known as kinetoplast, within...
Parasites of medical importance, such as and are characterized by the presence of thousands of circular DNA molecules forming a structure known as kinetoplast, within the mitochondria. The maxicircles, which are equivalent to the mitochondrial genome in other eukaryotes, have been proposed as a promising phylogenetic marker. Using whole-DNA sequencing data, it is also possible to assemble maxicircle sequences as shown here and in previous works. In this study, based on data available in public databases and using a bioinformatics workflow previously reported by our group, we assembled the complete coding region of the maxicircles for 26 prototypical strains of trypanosomatid species. Phylogenetic analysis based on this dataset resulted in a robust tree showing an accurate taxonomy of kinetoplastids, which was also able to discern between closely related species that are usually difficult to discriminate by classical methodologies. In addition, we provide a dataset of the maxicircle sequences of 60 field isolates from America, Western Europe, North Africa, and Eastern Europe. In agreement with previous studies, our data indicate that parasites from Brazil are highly homogeneous and closely related to European strains, which were transferred there during the discovery of America. However, this study showed the existence of different populations/clades within the Mediterranean region. A maxicircle signature for each clade has been established. Interestingly, two clades were found coexisting in the same region of Spain, one similar to the American strains, represented by the Spanish JPCM5 reference strain, and the other, named "non-JPC like", may be related to an important leishmaniasis outbreak that occurred in Madrid a few years ago. In conclusion, the maxicircle sequence emerges as a robust molecular marker for phylogenetic analysis and species typing within the kinetoplastids, which also has the potential to discriminate intraspecific variability.
Topics: Genome, Mitochondrial; Humans; Leishmania infantum; Leishmaniasis; Phylogeny; Trypanosoma
PubMed: 35741832
DOI: 10.3390/genes13061070 -
Comparative transcriptomic analysis of antimony resistant and susceptible Leishmania infantum lines.Parasites & Vectors Nov 2020One of the major challenges to leishmaniasis treatment is the emergence of parasites resistant to antimony. To study differentially expressed genes associated with drug... (Comparative Study)
Comparative Study
BACKGROUND
One of the major challenges to leishmaniasis treatment is the emergence of parasites resistant to antimony. To study differentially expressed genes associated with drug resistance, we performed a comparative transcriptomic analysis between wild-type and potassium antimonyl tartrate (Sb)-resistant Leishmania infantum lines using high-throughput RNA sequencing.
METHODS
All the cDNA libraries were constructed from promastigote forms of each line, sequenced and analyzed using STAR for mapping the reads against the reference genome (L. infantum JPCM5) and DESeq2 for differential expression statistical analyses. All the genes were functionally annotated using sequence similarity search.
RESULTS
The analytical pipeline considering an adjusted p-value < 0.05 and fold change > 2.0 identified 933 transcripts differentially expressed (DE) between wild-type and Sb-resistant L. infantum lines. Out of 933 DE transcripts, 504 presented functional annotation and 429 were assigned as hypothetical proteins. A total of 837 transcripts were upregulated and 96 were downregulated in the Sb-resistant L. infantum line. Using this DE dataset, the proteins were further grouped in functional classes according to the gene ontology database. The functional enrichment analysis for biological processes showed that the upregulated transcripts in the Sb-resistant line are associated with protein phosphorylation, microtubule-based movement, ubiquitination, host-parasite interaction, cellular process and other categories. The downregulated transcripts in the Sb-resistant line are assigned in the GO categories: ribonucleoprotein complex, ribosome biogenesis, rRNA processing, nucleosome assembly and translation.
CONCLUSIONS
The transcriptomic profile of L. infantum showed a robust set of genes from different metabolic pathways associated with the antimony resistance phenotype in this parasite. Our results address the complex and multifactorial antimony resistance mechanisms in Leishmania, identifying several candidate genes that may be further evaluated as molecular targets for chemotherapy of leishmaniasis.
Topics: Animals; Antimony; Antiprotozoal Agents; Drug Resistance; Leishmania infantum; Protozoan Proteins; Transcriptome
PubMed: 33256787
DOI: 10.1186/s13071-020-04486-4 -
Memorias Do Instituto Oswaldo Cruz Aug 2013Pentavalent antimonials such as meglumine antimoniate (MA) are the primary treatments for leishmaniasis, a complex disease caused by protozoan parasites of the genus...
Pentavalent antimonials such as meglumine antimoniate (MA) are the primary treatments for leishmaniasis, a complex disease caused by protozoan parasites of the genus Leishmania . Despite over 70 years of clinical use, their mechanisms of action, toxicity and pharmacokinetics have not been fully elucidated. Radiotracer studies performed on animals have the potential to play a major role in pharmaceutical development. The aims of this study were to prepare an antimony radiotracer by neutron irradiation of MA and to determine the biodistribution of MA in healthy and Leishmania (Leishmania) infantum chagasi-infected mice. MA (Glucantime®) was neutron irradiated inside the IEA-R1 nuclear reactor, producing two radioisotopes, ¹²²Sb and ¹²⁴Sb, with high radionuclidic purity and good specific activity. This irradiated compound presented anti-leishmanial activity similar to that of non-irradiated MA in both in vitro and in vivo evaluations. In the biodistribution studies, healthy mice showed higher uptake of antimony in the liver than infected mice and elimination occurred primarily through biliary excretion, with a small proportion of the drug excreted by the kidneys. The serum kinetic curve was bi-exponential, with two compartments: the central compartment and another compartment associated with drug excretion. Radiotracers, which can be easily produced by neutron irradiation, were demonstrated to be an interesting tool for answering several questions regarding antimonial pharmacokinetics and chemotherapy.
Topics: Animals; Antimony; Antiprotozoal Agents; Cricetinae; Female; Leishmania infantum; Leishmaniasis; Meglumine; Meglumine Antimoniate; Mice, Inbred BALB C; Organometallic Compounds; Radioisotopes; Radiopharmaceuticals; Time Factors; Tissue Distribution
PubMed: 23903979
DOI: 10.1590/0074-0276108052013014 -
Experimental Parasitology 2021The failures in the treatment of leishmaniasis is an increasing problem around the world, especially related to resistance. Thus, we describe the synthesis and in vivo...
The failures in the treatment of leishmaniasis is an increasing problem around the world, especially related to resistance. Thus, we describe the synthesis and in vivo anti-Leishmania activity of alkylphosphocholine and alkyltriazoles; besides, their likely action mechanisms stem from some eventual inhibition of parasite enzymes using computational tools. These compounds were tested in an in vivo hamster model infected with Leishmania Leishmania infantum chagasi. Fifty days after parasite inoculation, the two compounds 12-azidedodecylphosphocholine (3) and 3-(1-(12-fluorododecyl)-1H-1,2,3-triazol-1-yl)propano-1-ol (9), were separately administered once a day as oral suspensions (25 and 12.5 mg/kg/day, respectively) during ten days, and their efficacy was compared to the reference compound pentavalent antimonial Glucantime (GLU). Compound 3 significantly reduced the number of parasites in the spleen (4.93 × 10 amastigotes/g) and liver (4.52 × 10 amastigotes/g). Compound 9 reduced the number of amastigotes in the spleen to 1.30 × 10 and 1.36 × 10 amastigotes/g in the liver. GLU was the most effective overall treatment (7.50 × 10 and 2.28 × 10 amastigotes/g in the spleen and liver, respectively). The high activity levels of these compounds in vivo may stem from their high in vitro leishmanicidal activity and lipophilicity. The in silico absorption, distribution, metabolism, and excretion studies also showed some anti-Leishmania potential. Compound 9 had more lipophilic characteristics than those of compound 3. In silico studies of the nine enzymes of compounds 3 and 9 showed significant evidence of interactions with nicotimidase and tyrosine aminotransferase, demonstrating possible inhibition enzymes present in L. (L.) infantum chagasi. These compounds could be a promising template for developing a new class of leishmanicidal agents, by oral route, and deserve further investigation to explore different therapeutic regimens.
Topics: Administration, Oral; Animals; Antiprotozoal Agents; Cricetinae; DNA, Complementary; Female; Leishmania infantum; Leishmaniasis, Visceral; Liver; Mesocricetus; Molecular Docking Simulation; Phosphorylcholine; RNA; Spleen; Triazoles
PubMed: 34144040
DOI: 10.1016/j.exppara.2021.108123 -
Molecular and Biochemical Parasitology Aug 2013The emergence of drug-resistant Leishmania species is a significant problem in several countries. A comparative proteomic analysis of antimony-susceptible and... (Comparative Study)
Comparative Study
The emergence of drug-resistant Leishmania species is a significant problem in several countries. A comparative proteomic analysis of antimony-susceptible and antimony-resistant Leishmania braziliensis (LbSbR) and Leishmania infantum chagasi (LcSbR) lines was carried out using two-dimensional gel electrophoresis (2-DE) followed by mass spectrometry (LC/MS/MS) for protein identification. Out of 132 protein spots exclusive or up-regulated submitted to MS, we identified 80 proteins that corresponded to 57 distinct proteins. Comparative analysis of data showed that most of the protein spots with differential abundance in both species are involved in antioxidant defense, general stress response, glucose and amino acid metabolism, and cytoskeleton organization. Five proteins were commonly more abundant in both SbIII-resistant Leishmania lines: tryparedoxin peroxidase, alpha-tubulin, HSP70, HSP83, and HSP60. Analysis of the protein abundance by Western blotting assays confirmed our proteomic data. These assays revealed that cyclophilin-A is less expressed in both LbSbR and LcSbR lines. On the other hand, the expression of pteridine reductase is higher in the LbSbR line, whereas tryparedoxin peroxidase is overexpressed in both LbSbR and LcSbR lines. Together, these results show that the mechanism of antimony-resistance in Leishmania spp. is complex and multifactorial.
Topics: Antimony; Drug Resistance; Electrophoresis, Gel, Two-Dimensional; Leishmania braziliensis; Leishmania infantum; Mass Spectrometry; Proteome; Proteomics; Protozoan Proteins
PubMed: 23831370
DOI: 10.1016/j.molbiopara.2013.06.006