Assessing the effects of Leishmania (Leishmania) infantum and L. (L.) amazonensis infections in macrophages using a quantitative proteome approach.

Leishmania (Leishmania) infantum is the causative agent of visceral leishmaniasis, while L. (L.) amazonensis is associated with localized cutaneous and diffuse leishmaniasis, which can affect different organ tissues leading to visceral manifestations in some hosts. The wide range of clinical manifestations of leishmaniasis depends on host factors such as the immune response and on the species of Leishmania involved in the infection. Macrophages are the main infected cells in the vertebrate host, and proteins play a pivotal role in Leishmania-macrophage interactions. Here, we performed difference gel electrophoresis (DIGE) and shotgun quantitative mass spectrometry-based proteomics by means of tandem mass tags (TMT) isobaric peptide labeling followed by LC-MS/MS to investigate differentially abundant proteins in BALB/c macrophages infected with these Leishmania species. Using DIGE for comparison, we found that 2.34% spots (29/1240) were differentially intense in infected murine macrophages. Leishmania (L.) infantum and L. (L.) amazonensis induced similar changes in the host cells; 11 spots were selected as differentially intense in each species and seven in the uninfected control group. Using TMT, 5939 Mus musculus proteins were identified, of which 410 and 433 were differentially abundant in L. (L.) infantum and L. (L.) amazonensis infections, respectively, while 170 proteins were commonly regulated by both the species. Gene ontology enrichment analysis indicated that Leishmania infection interfered with apoptotic mechanisms in macrophages and induced epigenetic changes that may affect gene transcription. Moreover, downregulation of proteins such as PYCARD and MyD88 seemed to influence the inflammatory process in L. (L.) amazonensis infection, whereas upregulation of TAP1 and ERAP1 was involved in the adaptive immune response in L. (L.) infantum infection. Differentially abundant proteins identified in this study may contribute to a better understanding of the factors that determine the course of infection. Our results suggest several possible targets for vaccines, drugs, and diagnosis of leishmaniasis.

Assessing the composition of the plasma membrane of Leishmania (Leishmania) infantum and L. (L.) amazonensis using label-free proteomics.

Protozoan parasites of the genus Leishmania are causative agents of leishmaniasis, a wide range of diseases affecting 12 million people worldwide. The species L. infantum and L. amazonensis are etiologic agents of visceral and cutaneous leishmaniasis, respectively. Most proteome analyses of Leishmania have been carried out on whole-cell extracts, but such an approach tends to underrepresent membrane-associated proteins due to their high hydrophobicity and low solubility. Considering the relevance of this category of proteins in virulence, invasiveness and the host-parasite interface, this study applied label-free proteomics to assess the plasma membrane sub-proteome of L. infantum and L. amazonensis. The number of proteins identified in L. infantum and L. amazonensis promastigotes was 1168 and 1455, respectively. After rigorous data processing and mining, 157 proteins were classified as putative plasma membrane-associated proteins, of which 56 proteins were detected in both species, six proteins were detected only in L. infantum and 39 proteins were exclusive to L. amazonensis. The quantitative analysis revealed that two proteins were more abundant in L. infantum, including the glucose transporter 2, and five proteins were more abundant in L. amazonensis. The identified proteins associated with distinct processes and functions. In this regard, proteins of L. infantum were linked to metabolic processes whereas L. amazonensis proteins were involved in signal transduction. Moreover, transmembrane transport was a significant process among the group of proteins detected in both species and members of the superfamily of ABC transporters were highly represented. Interestingly, some proteins of this family were solely detected in L. amazonensis, such as ABCA9. GP63, a well-known virulence factor, was the only GPI-anchored protein identified in the membrane preparations of both species. Finally, we found several proteins with uncharacterized functions, including differentially abundant ones, highlighting a gap in the study of Leishmania proteins. Proteins characterization could provide a better biological understanding of these parasites and deliver new possibilities regarding the discovery of therapeutic targets, drug resistance and vaccine candidates.

Immunohistochemical study of renal fibropoiesis associated with dogs naturally and experimentally infected with two different strains of Leishmania (L.) infantum.

The objectives of this work were to study some pathological aspects of kidneys obtained from dogs naturally infected with Leishmania infantum and from dogs experimentally infected with two different strains of L infantum with special emphasis on fibrotic process. Seventy eight specimens of paraffin-embedded kidney fragments were collected as follows: (a) CNI group composed by 62 kidney samples of adult mongrel dogs, naturally infected with L infantum; (b) BH401 group composed by five kidney samples of adult Beagles experimentally infected with L infantum strain MCAN BR/2002/BH401; (c) BH400 group composed by eleven kidney samples of adult Beagles experimentally infected with L infantum strain MCAN/BR/2000/BH400, at the same dose and same route of the previous group, denominated group BH400; Control group (CC) composed by four kidney samples of adult Beagles. All animals revealed glomerular and interstitial fibropoiesis associated with different types of glomerulonephritis and chronic interstitial nephritis. Fibrosis was markedly more intense in the BH401 group, followed by animals in the CNI group. Markers for myofibroblasts (mesenchymal markers) such as alpha-actin (α-SMA), vimentin and the cytokine transforming growth factor beta (TGF-ß) were done by immunohistochemistry. BH401 group showed higher expression of all these markers than others. Intracellular amastigotes forms of Leishmania was mainly found in BH401. These results could be indicating that the MCAN/BR/2002/BH401 strain is a good choice for the study of renal LVC experimental model.

Cysteine Proteases from V. cundinamarcensis (C. candamarcensis) Inhibit Melanoma Metastasis and Modulate Expression of Proteins Related to Proliferation, Migration and Differentiation.

Previous studies showed that P1G10, a proteolytic fraction from Vasconcellea cundinamarcensis latex, reduced the tumor mass in animals bearing melanoma, increased in vitro DNA fragmentation and decreased cell adhesion. Here, we present some molecular and cellular events related to the antimetastatic effect induced by the CMS-2 fraction derived from P1G10 in metastatic melanoma B16-F10 and melanocyte Melan-a. Using difference gel electrophoresis and mass spectrometry, we identified four proteins overexpressed in tumor cells, all of them related to proliferation, survival, migration and cell invasion, that had their expression normalized upon treatment with CMS-2: nucleophosmin 1, heat shock protein 65, calcyclin binding protein and eukaryotic translation initiation factor 4H. In addition, some antioxidant and glycolytic enzymes show increased expression after exposure to CMS-2, along with an induction of melanogenesis (differentiation marker). The down regulation of cofilin 1, a protein involved in cell motility, may explain the inhibition of cell migration and dendritic-like outgrowth in B16-F10 and Melan-a, observed after CMS-2 treatment. Taken together, it is argued that CMS-2 modulates the expression of proteins related to metastatic development, driving the cell to a more differentiated-like state. These effects support the CMS-2 antimetastatic activity and place this fraction in the category of anticancer agent.

Using QCM and SPR for the Kinetic Evaluation of the Binding Between A New Recombinant Chimeric Protein and Specific Antibodies of the Visceral Leishmaniasis.

In the present study, the surface plasmon resonance (SPR) and quartz crystal microbalance (QCM) techniques were employed to kinetically evaluate the binding affinity of a new recombinant chimeric protein (CP10) toward anti-Leishmania infantum antibodies for the immunodiagnostics of the visceral leishmaniasis (VL). This chimeric protein was formed by the union in a same artificial coding DNA of ten different peptides, which showed themselves reactive toward positive canine serum for VL. Using the CP10 in enzyme-linked immunosorbent assays (ELISA), it was possible to detect 80% of the asymptomatic infected dogs. After this, SPR and QCM immunosensors were constructed by the covalent immobilization of the CP10 on a self-assembled monolayer (SAM) formed by adsorption of alkanethiol on gold substrates. The thickness (6.80 nm) and the refractive index (1.475) of the protein on the SAM were simultaneously determined through SPR curves measured in different wavelengths (670 and 785 nm). Interactions between the CP10 and its specific IgGs (anti-CP10 antibodies) were characterized by the electrochemical impedance spectroscopy, SPR and QCM techniques. The equilibrium dissociation constant obtained by SPR (K(D) = 8.27 x 10(-10) mol.L(-1)) and QCM (K(D) = 2.42 x 10(- 10) mol.L(-1)) demonstrated high binding affinity of the CP10 toward anti-CP10 antibodies. In this sense, this work quantitatively proves the strong antigenic character of a new recombinant chimeric protein, giving evidence to potential contribution for the use of this protein in programs of control of the VL.

Proteomic analysis of the soluble proteomes of miltefosine-sensitive and -resistant Leishmania infantum chagasi isolates obtained from Brazilian patients with different treatment outcomes.

The mechanism of miltefosine-resistance in Leishmania spp. has been partially determined in experimental resistant lines; however, studies using clinical isolates with different miltefosine susceptibilities are still needed. In our study, we used a proteomic 2D-DIGE/MS approach to study different protein abundances in miltefosine-sensitive and -resistant Leishmania infantum chagasi isolates from visceral leishmaniasis patients with different miltefosine treatment outcomes. The high-resolution proteome obtained from these isolates showed 823 matched spots and 46 spots exhibited different abundances between the isolates. Out of these differentially expressed spots, 26 (56.5%) showed greater and 20 (43.5%) showed lower expression of the resistant isolate compared to the sensitive isolate. MALDI/TOF-TOF mass spectrometry allowed the identification of 32 spots with unique protein identification correspondent to 22 non-redundant proteins. Most of the proteins up-regulated in the proteome miltefosine-resistant isolates were associated with redox homeostasis, stress response, protection to apoptosis, and drug translocation. These differentially expressed proteins are likely involved in miltefosine natural resistance and suggest that the miltefosine-resistance mechanism in Leishmania is multifactorial. BIOLOGICAL SIGNIFICANCE: Visceral leishmaniasis (VL) is a serious disease with a challenging treatment plan requiring the prolonged and painful applications of poorly tolerated toxic drugs. Therefore, the identification of miltefosine, an effective and safe oral drug, was considered a significant advancement in leishmaniasis therapy. However, different sensitivities to miltefosine in Leishmania have been observed in clinically relevant species, and the biological mechanism by which clinical isolates of Leishmania acquire drug resistance is poorly understood. Our work aims to elucidate the mechanism of natural resistance to miltefosine in Leishmania by studying the isolates from VL patients who displayed different miltefosine treatment outcomes.

Trypanosoma cruzi: characterisation of the gene encoding tyrosine aminotransferase in benznidazole-resistant and susceptible populations.

Various biochemical differences exist between mammalian tyrosine aminotransferase (TAT) and its analogue in Trypanosoma cruzi (TcTAT), the causative agent of Chagas disease. Moreover, TcTAT is over-expressed in strains of the parasite that are resistant to benznidazole (BZ), a drug currently used in chemotherapy. TAT has thus been indicated as a potential target for the development of new chemotherapeutic agents. In the present study, the TcTAT gene has been characterised in 14 BZ-resistant and susceptible strains and clones of T. cruzi. A unique transcript of 2.0kb and similar levels of TcTAT mRNA were observed in all parasite populations. TcTAT gene is organized in a tandem multicopy array and is located on 8 chromosomal bands that vary from 785-2500kb. No amplification of TcTAT was observed in the parasite genome. A 42kDa protein expressed by TcTAT was present in all T. cruzi samples. The results suggest that TcTAT is not directly associated with the T. cruzi drug resistance phenotype. However, it may act as a general secondary compensatory mechanism or stress response factor rather than as a key component of the specific primary resistance mechanism in T. cruzi.