Treatment with benznidazole and pentoxifylline regulates microRNA transcriptomic profile in a murine model of Chagas chronic cardiomyopathy

Chronic Chagas cardiomyopathy (CCC) is one of the leading causes of morbidity and mortality due to cardiovascular disorders in endemic areas of Chagas disease (CD), a neglected tropical illness caused by the protozoan parasite Trypanosoma cruzi. CCC is characterized by parasite persistence and inflammatory response in the heart tissue, which occur parallel to microRNA (miRNA) alterations. Here, we investigated the miRNA transcriptome profiling in the cardiac tissue of chronically T. cruzi-infected mice treated with a suboptimal dose of benznidazole (Bz), the immunomodulator pentoxifylline alone (PTX), or the combination of both (Bz+PTX), following the CCC onset. At 150 days post-infection, Bz, PTX, and Bz+PTX treatment regimens improved electrocardiographic alterations, reducing the percentage of mice afflicted by sinus arrhythmia and second-degree atrioventricular block (AVB2) when compared with the vehicle-treated animals. miRNA Transcriptome profiling revealed considerable changes in the differential expression of miRNAs in the Bz and Bz+PTX treatment groups compared with the control (infected, vehicle-treated) group. The latter showed pathways related to organismal abnormalities, cellular development, skeletal muscle development, cardiac enlargement, and fibrosis, likely associated with CCC. Bz-Treated mice exhibited 68 differentially expressed miRNAs related to signaling pathways like cell cycle, cell death and survival, tissue morphology, and connective tissue function. Finally, the Bz+PTX-treated group revealed 58 differentially expressed miRNAs associated with key signaling pathways related to cellular growth and proliferation, tissue development, cardiac fibrosis, damage, and necrosis/cell death. The T. cruzi-induced upregulation of miR-146b-5p, previously shown in acutely infected mice and in vitro T. cruzi-infected cardiomyocytes, was reversed upon Bz and Bz+PTX treatment regimens when further experimentally validated. Our results further our understanding of molecular pathways related to CCC progression and evaluation of treatment response. Moreover, the differentially expressed miRNAs may serve as drug targets, associated molecular therapy, or biomarkers of treatment outcomes.

Modulation of miR-145-5p and miR-146b-5p levels is linked to reduced parasite load in H9C2 Trypanosoma cruzi infected cardiomyoblasts

In the heart tissue of acutely Trypanosoma cruzi-infected mice miR-145-5p and miR-146b-5p are, respectively, downregulated and upregulated. Here, we used the H9C2 rat cardiomyoblast cell line infected with the Colombian T. cruzi strain to investigate the parasite-host cell interplay, focusing on the regulation of miR-145-5p and miR-146b-5p expression. Next, we explored the effects of interventions with the trypanosomicidal drug Benznidazole (Bz) alone or combined with Pentoxifylline (PTX), a methylxanthine derivative shown to modulate immunological and cardiac abnormalities in a model of chronic chagasic cardiomyopathy, on parasite load and expression of miR-145-5p and miR-146b-5p. The infection of H9C2 cells with trypomastigote forms allowed parasite cycle with intracellular forms multiplication and trypomastigote release. After 48 and 144 h of infection, upregulation of miR-145-5p (24 h: 2.38 ± 0.26; 48 h: 3.15 ± 0.9-fold change) and miR-146b-5b (24 h: 2.60 ± 0.46; 48 h: 2.97 ± 0.23-fold change) was detected. The peak of both miRNA levels paralleled with release of trypomastigote forms. Addition of 3 µM and 10 µM of Bz 48 h after infection reduced parasite load but did not interfere with miR-145-5p and miR-146b-5p levels. Addition of PTX did not interfere with Bz-induced parasite control efficacy. Conversely, combined Bz + PTX treatment decreased the levels of both microRNAs, resembling the expression levels detected in non-infected H9C2 cells. Moreover, the use of miR-145-5p and miR-146b-5p mimic/inhibitor systems before infection of H9C2 cells decreased parasite load, 72 h postinfection. When H9C2 cells were treated with miR-145-5p and miR-146b-5p mimic/inhibitor 48 h after infection, all the used systems, except the miR-146b-5p inhibitor, reduced parasite load. Altogether, our data indicate that these microRNAs putatively control signaling pathways crucial for parasite–host cell interaction. Thus, miR-145-5p and miR-146b-5p deserve to be further investigated as biomarkers of parasite control and tools to identify therapeutic adjuvants to etiological treatment in Chagas disease.

Potato apyrase reduces granulomatous area and increases presence of multinucleated giant cells in murine schistosomiasis

Granulomas are inflammatory tissue responses directed to a set of antigens. Trapped Schistosoma mansoni eggs promote productive granulomas in the tissues, and they are the main damage caused by schistosomiasis. Some S. mansoni antigenic proteins may have a direct involvement in the resolution of the granulomatous response. The ATP diphosphohydrolases isoforms of this parasite are immunogenic, expressed in all phases of the parasite life cycle and secreted by eggs and adult worms. Potato apyrase is a vegetable protein that cross-reactive with parasite ATP diphosphohydrolases isoforms. In this study, the vegetable protein was purified, before being inoculated in C57BL/6 mice that were later infected with cercariae. Sixty days after infection, adult worms were recovered, antibodies and cytokines were measured, and morphological granuloma alterations evaluated. Immunization of the animals induced significant levels of IgG and IgG1 antibodies and IFN-γ, IL-10 and IL-5 cytokines, but not IL-13, suggesting that potato apyrase is an immunoregulatory protein. Supporting this hypothesis, it was found that liver damage associated with schistosomiasis was mitigated, reducing the size of the areas affected by granuloma to 35% and increasing the presence of multinucleated giant cells in this environment. In conclusion, potato apyrase was found to be effective immunomodulatory antigen for murine schistosomiasis.

Treatment With Suboptimal Dose of Benznidazole Mitigates Immune Response Molecular Pathways in Mice With Chronic Chagas Cardiomyopathy

Chronic Chagas cardiomyopathy (CCC) is the most frequent and severe form of Chagas disease, a neglected tropical illness caused by the protozoan Trypanosoma cruzi, and the main cause of morbimortality from cardiovascular problems in endemic areas. Although efforts have been made to understand the signaling pathways and molecular mechanisms underlying CCC, the immunological signaling pathways regulated by the etiological treatment with benznidazole (Bz) has not been reported. In experimental CCC, Bz combined with the hemorheological and immunoregulatory agent pentoxifylline (PTX) has beneficial effects on CCC. To explore the molecular mechanisms of Bz or Bz+PTX therapeutic strategies, C57BL/6 mice chronically infected with the T. cruzi Colombian strain (discrete typing unit TcI) and showing electrocardiographic abnormalities were submitted to suboptimal dose of Bz or Bz+PTX from 120 to 150 days postinfection. Electrocardiographic alterations, such as prolonged corrected QT interval and heart parasite load, were beneficially impacted by Bz and Bz+PTX. RT-qPCR TaqMan array was used to evaluate the expression of 92 genes related to the immune response in RNA extracted from heart tissues. In comparison with non-infected mice, 30 genes were upregulated, and 31 were downregulated in infected mice. Particularly, infection upregulated the cytokines IFN-γ, IL-12b, and IL-2 (126-, 44-, and 18-fold change, respectively) and the T-cell chemoattractants CCL3 and CCL5 (23- and 16-fold change, respectively). Bz therapy restored the expression of genes related to inflammatory response, cellular development, growth, and proliferation, and tissue development pathways, most probably linked to the cardiac remodeling processes inherent to CCC, thus mitigating the Th1-driven response found in vehicle-treated infected mice. The combined Bz+PTX therapy revealed pathways related to the modulation of cell death and survival, and organismal survival, supporting that this strategy may mitigate the progression of CCC. Altogether, our results contribute to the better understanding of the molecular mechanisms of the immune response in the heart tissue in chronic Chagas disease and reinforce that parasite persistence and dysregulated immune response underpin CCC severity. Therefore, Bz and Bz+PTX chemotherapies emerge as tools to interfere in these pathways aiming to improve CCC prognosis.

Insights into the proteomic profile and gene expression of Lutzomyia longipalpis-derived Lulo cell line

BACKGROUND

Lutzomyia longipalpis-derived cell line (Lulo) has been suggested as a model for studies of interaction between sandflies and Leishmania.

OBJECTIVES

Here, we present data of proteomic and gene expression analyses of Lulo cell related to interactions with Leishmania (Viannia) braziliensis.

METHODS

Lulo cell protein extracts were analysed through a combination of two-dimensional gel electrophoresis and mass spectrometry and resulting spots were further investigated in silico to identify proteins using Mascot search and, afterwards, resulting sequences were applied for analysis with VectorBase.

RESULTS

Sixty-four spots were identified showing similarities to other proteins registered in the databases and could be classified according to their biological function, such as ion-binding proteins (23%), proteases (14%), cytoskeletal proteins (11%) and interactive membrane proteins (9.5%). Effects of interaction with L. (V.) braziliensis with the expression of three genes (enolase, tubulin and vacuolar transport protein) were observed after an eight-hour timeframe and compared to culture without parasites, and demonstrated the impact of parasite interaction with the expression of the following genes: LLOJ000219 (1.69-fold), LLOJ000326 (1.43-fold) and LLOJ006663 (2.41-fold).

CONCLUSIONS

This set of results adds relevant information regarding the usefulness of the Lulo cell line for studies with Leishmania parasites that indicate variations of protein expression.

Screening of plant derived chalcones on the inhibition of potato apyrase: Potential protein biotechnological applications in health

NTPDases (EC 3.6.1.5) are enzymes belonging to a protein family which have as a common feature the ability to hydrolyze di- and triphosphate nucleotides (ADP and ATP) to monophosphate nucleosides (AMP) in the presence of Ca⁺² and Mg⁺. The potato apyrase has been the first protein of the NTPDase family to be purified. In mammals, these enzymes are involved in physiologic and sick processes as thromboregulation, inflammatory and immunologic responses. In this study, we investigated the in vitro potential of synthetic chalcones on the inhibition of potato apyrase purified from Solanum tuberosum. The protein was purified with high grade purity and its identity was confirmed by electrophoresis, western blot, and LC-MS/MS. Five out of the eight chemically synthetized chalcones analyzed in this study showed significant inhibition of the apyrase activity. The compound with the best rate of inhibition of ATP hydrolytic activity was able to promote 54% inhibition with a concentration of 3.125 μM. Ticlopidine, used as an inhibition drug control, was able to promote inhibitions around 50% of the activity (IC₅₀ = 2.167 μM). Our results with the potato apyrase inhibition with the synthetic chalcones suggest that these compounds may use as potential lead candidates for the treatment of some diseases associated with nucleotides.