scholarly journals The Dialogue of the Host-Parasite Relationship:Leishmaniaspp. andTrypanosoma cruziInfection

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
Carlos Gustavo Vieira de Morais ◽  
Ana Karina Castro Lima ◽  
Rodrigo Terra ◽  
Rosiane Freire dos Santos ◽  
Silvia Amaral Gonçalves Da-Silva ◽  
...  
Keyword(s):  
Immune Response ◽  
Trypanosoma Cruzi ◽  
Neglected Tropical Diseases ◽  
New Drugs ◽  
Host Cells ◽  
Protective Response ◽  
Limited Efficacy ◽  
Causative Agents ◽  
Host Parasite ◽  
Emergence Of Resistance

The intracellular protozoaLeishmaniaspp. andTrypanosoma cruziand the causative agents of Leishmaniasis and Chagas disease, respectively, belong to the Trypanosomatidae family. Together, these two neglected tropical diseases affect approximately 25 million people worldwide. Whether the host can control the infection or develops disease depends on the complex interaction between parasite and host. Parasite surface and secreted molecules are involved in triggering specific signaling pathways essential for parasite entry and intracellular survival. The recognition of the parasite antigens by host immune cells generates a specific immune response.Leishmaniaspp. andT. cruzihave a multifaceted repertoire of strategies to evade or subvert the immune system by interfering with a range of signal transduction pathways in host cells, which causes the inhibition of the protective response and contributes to their persistence in the host. The current therapeutic strategies in leishmaniasis and trypanosomiasis are very limited. Efficacy is variable, toxicity is high, and the emergence of resistance is increasingly common. In this review, we discuss the molecular basis of the host-parasite interaction ofLeishmaniaandTrypanosoma cruziinfection and their mechanisms of subverting the immune response and how this knowledge can be used as a tool for the development of new drugs.

scholarly journals Amaryllidaceae alkaloids with anti-Trypanosoma cruzi activity

2020 ◽  
Author(s):  
Nieves Martinez-Peinado ◽  
Nuria Cortes-Serra ◽  
Laura Torras-Claveria ◽  
Maria-Jesus Pinazo ◽  
Joaquim Gascon ◽  
...  
Keyword(s):  
Natural Products ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
New Drugs ◽  
Host Cells ◽  
Amaryllidaceae Alkaloids ◽  
Cytotoxicity Assays ◽  
Limited Efficacy ◽  
Single Compound ◽  
New Compounds

Abstract Background: Chagas disease, caused by the protozoan Trypanosoma cruzi, is a neglected disease that affects ~7 million people worldwide. Development of new drugs to treat the infection remains a priority since those currently available have frequent side effects and limited efficacy at the chronic stage. Natural products provide a pool of diversity structures to lead the chemical synthesis of novel molecules for this purpose. Herein we analyzed the anti- T. cruzi activity of 9 alkaloids derived from plants of the Amaryllidaceae family. Methods: the activity of each alkaloid was assessed by means of a newly developed anti- T. cruzi phenotypic assay. We further evaluated the compounds that inhibited the parasite growth on two distinct cytotoxicity assays to discard those that were toxic to host cells and assure parasite selectivity. Results: we identified a single compound (hippeastrine 2 ) that was selectively active against the parasite yielding selectivity indexes of 12.7 and 35.2 against Vero and HepG2 cells, respectively. Conclusions: results reported here suggest that natural products are an interesting source of new compounds for the development of drugs against Chagas disease.

scholarly journals Amaryllidaceae alkaloids with anti-Trypanosoma cruzi activity

2020 ◽  
Author(s):  
Nieves Martinez-Peinado ◽  
Nuria Cortes-Serra ◽  
Laura Torras-Claveria ◽  
Maria-Jesus Pinazo ◽  
Joaquim Gascon ◽  
...  
Keyword(s):  
Natural Products ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Specific Activity ◽  
New Drugs ◽  
Host Cells ◽  
Amastigote Stage ◽  
Limited Efficacy ◽  
Single Compound ◽  
New Compounds

Abstract Background: Chagas disease, caused by the protozoan Trypanosoma cruzi, is a neglected disease that affects ~7 million people worldwide. Development of new drugs to treat the infection remains a priority since those currently available have frequent side effects and limited efficacy at the chronic stage. Natural products provide a pool of diversity structures to lead the chemical synthesis of novel molecules for this purpose. Herein we analyzed the anti- T. cruzi activity of 9 alkaloids derived from plants of the Amaryllidaceae family. Methods: the activity of each alkaloid was assessed by means of an anti- T. cruzi phenotypic assay. We further evaluated the compounds that inhibited the parasite growth on two distinct cytotoxicity assays to discard those that were toxic to host cells and assure parasite selectivity. Results: we identified a single compound (hippeastrine 2 ) that was selectively active against the parasite yielding selectivity indexes of 12.7 and 35.2 against Vero and HepG2 cells, respectively. Moreover, it showed specific activity against the amastigote stage (IC 50 = 3.31 μM). Conclusions: results reported here suggest that natural products are an interesting source of new compounds for the development of drugs against Chagas disease.

scholarly journals Amaryllidaceae alkaloids with anti-Trypanosoma cruzi activity

2020 ◽  
Author(s):  
Nieves Martinez-Peinado ◽  
Nuria Cortes-Serra ◽  
Laura Torras-Claveria ◽  
Maria-Jesus Pinazo ◽  
Joaquim Gascon ◽  
...  
Keyword(s):  
Natural Products ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Specific Activity ◽  
New Drugs ◽  
Host Cells ◽  
Amastigote Stage ◽  
Limited Efficacy ◽  
Single Compound ◽  
New Compounds

Abstract Background: Chagas disease, caused by the protozoan Trypanosoma cruzi, is a neglected disease that affects ~7 million people worldwide. Development of new drugs to treat the infection remains a priority since those currently available have frequent side effects and limited efficacy at the chronic stage. Natural products provide a pool of diversity structures to lead the chemical synthesis of novel molecules for this purpose. Herein we analyzed the anti- T. cruzi activity of 9 alkaloids derived from plants of the Amaryllidaceae family. Methods: the activity of each alkaloid was assessed by means of an anti- T. cruzi phenotypic assay. We further evaluated the compounds that inhibited the parasite growth on two distinct cytotoxicity assays to discard those that were toxic to host cells and assure parasite selectivity. Results: we identified a single compound (hippeastrine 2 ) that was selectively active against the parasite yielding selectivity indexes of 12.7 and 35.2 against Vero and HepG2 cells, respectively. Moreover, it showed specific activity against the amastigote stage (IC 50 = 3.31 μM). Conclusions: results reported here suggest that natural products are an interesting source of new compounds for the development of drugs against Chagas disease.

scholarly journals Amaryllidaceae alkaloids with anti-Trypanosoma cruzi activity.

2020 ◽  
Author(s):  
Nieves Martinez-Peinado ◽  
Nuria Cortes-Serra ◽  
Laura Torras-Claveria ◽  
Maria-Jesus Pinazo ◽  
Joaquim Gascon ◽  
...  
Keyword(s):  
Natural Products ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Specific Activity ◽  
New Drugs ◽  
Host Cells ◽  
Amastigote Stage ◽  
Limited Efficacy ◽  
Single Compound ◽  
New Compounds

Abstract Background: Chagas disease, caused by the protozoan Trypanosoma cruzi, is a neglected disease that affects ~7 million people worldwide. Development of new drugs to treat the infection remains a priority since those currently available have frequent side effects and limited efficacy at the chronic stage. Natural products provide a pool of diversity structures to lead the chemical synthesis of novel molecules for this purpose. Herein we analyzed the anti-T. cruzi activity of 9 alkaloids derived from plants of the Amaryllidaceae family.Methods: the activity of each alkaloid was assessed by means of an anti-T. cruzi phenotypic assay. We further evaluated the compounds that inhibited the parasite growth on two distinct cytotoxicity assays to discard those that were toxic to host cells and assure parasite selectivity.Results: we identified a single compound (hippeastrine 2) that was selectively active against the parasite yielding selectivity indexes of 12.7 and 35.2 against Vero and HepG2 cells, respectively. Moreover, it showed specific activity against the amastigote stage (IC50 = 3.31 μM).Conclusions: results reported here suggest that natural products are an interesting source of new compounds for the development of drugs against Chagas disease.

scholarly journals Bioluminescent:fluorescent Trypanosoma cruzi Reporter Strains as Tools for Exploring Chagas Disease Pathogenesis and Drug Activity

2020 ◽  
Vol 26 ◽  
Author(s):  
Martin C. Taylor ◽  
Alexander I. Ward ◽  
Francisco Olmo ◽  
Amanda F. Francisco ◽  
Shiromani Jayawardhana ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Parasite Burden ◽  
New Drugs ◽  
Host Cells ◽  
Complex Nature ◽  
Disease Pathogenesis ◽  
Drug Activity ◽  
Cellular Environment

: Chagas disease results from infection with the trypanosomatid parasite Trypanosoma cruzi. Progress in developing new drugs has been hampered by the long term and complex nature of the condition and by our limited understanding of parasite biology. Technical difficulties in assessing the parasite burden during the chronic stage of infection have also proved to be a particular challenge. In this context, the development of non-invasive, highly sensitive bioluminescence imaging procedures, based on parasites that express a red-shifted luciferase, has greatly enhanced our ability to monitor infections in experimental models. Applications of this methodology have led to new insights into tissue tropism and infection dynamics, and have been a major driver in drug development. The system has been further modified by the generation of parasite reporter lines that express bioluminescent:fluorescent fusion proteins, an advance that has allowed chronic infections in mice to be examined at a cellular level. By exploiting bioluminescence to identify the rare sites of tissue infection, and fluorescence to detect T. cruzi at the level of individual host cells in histological sections, it has been possible to investigate the replication and differentiation status of parasites in vivo and to examine the cellular environment of infection foci. In combination, these data are providing a framework for the detailed dissection of disease pathogenesis and drug activity.

Methods of macrophages activation and their modulation for the prospection of new antileishmania drugs: a review

2021 ◽  
Vol 37 ◽  
pp. e37077
Author(s):  
Michel Muálem de Moraes Alves ◽  
Daniel Dias Rufino Arcanjo ◽  
Rita Cássia Viana de Carvalho ◽  
Layane Valéria Amorim ◽  
Ingredy Lopes dos Santos ◽  
...  
Keyword(s):  
Immune Response ◽  
Neglected Tropical Diseases ◽  
New Drugs ◽  
Tropical Diseases ◽  
First Line ◽  
Phagocytic Capacity ◽  
Activity Increase ◽  
Parasitic Zoonoses ◽  
Infected Cells ◽  
Cellular Immune

Leishmaniasis are a group of parasitic zoonoses provoked by protozoa from Leishmania genus and belonging to the group of neglected tropical diseases. The search and development for new drugs is necessary not only to investigate the activity against only the parasite, but also to investigate the possible synergistic effect of new drugs with the immune response of the host. In the present review, macrophages are pointed out as potential targets of the investigation of new antileishmanial drugs, and some methodologies in order to assess their activation as response to Leishmania-infected cells are presented. Macrophages are an important role in the cellular immune response, since they are cells from mononuclear phagocytic system, the first line of defense of the host, against parasites from Leishmania genus. Phagocytic capacity, lysosomal activity, increase of nitric oxide and intracellular calcium levels are parameters regarding assessment of macrophages activation which allow them to be more hostile in order to solve the infection and lead the patient to cure. In this context, we bring 19 substances already investigated and that activate macrophages, what makes them promising in the antileishmanial treatment. Therefore, assessment of macrophages activation, are important tools for discovery of immunomodulatory compounds which have potential to act in synergism with host immune response. Such compounds might be promising as monotherapy in the treatment of leishmaniasis, as well as being used as adjuvants in vaccines and/or in combination with conventional drugs.

scholarly journals Drug Resistance in Visceral Leishmaniasis

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Helena C. Maltezou
Keyword(s):  
Visceral Leishmaniasis ◽  
Neglected Tropical Diseases ◽  
Public Health Problem ◽  
New Drugs ◽  
World Health ◽  
Oral Agent ◽  
Molecular Surveillance ◽  
Health Organization ◽  
Combination Regimens ◽  
Emergence Of Resistance

Visceral leishmaniasis remains a public health problem worldwide. This illness was included by the World Health Organization in the list of neglected tropical diseases targeted for elimination by 2015. The widespread emergence of resistance to pentavalent antimonials in India where half cases occur globally and the unavailability of a vaccine in clinical use constitute major obstacles in achieving this goal. The last decade new antileishmanials became available, including the oral agent miltefosine. However, in poor endemic countries their wide use was curtailed because of the high costs, and also due to concerns of toxicity and emergence of resistance. Various mechanisms of antileishmanial resistance were identified recently in field isolates. Their elucidation will boost the design of new drugs and the molecular surveillance of resistance. Combination regimens should be evaluated in large trials. Overall, the development of antileishmanials has been generally slow; new drugs are needed. In order to control visceral leishmaniasis worldwide, treatment advances should become affordable in the poorest countries, where they are needed most.

scholarly journals Microorganisms as a Potential Source of Molecules to Control Trypanosomatid Diseases

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1388
Author(s):  
Manuel Jesús Chan-Bacab ◽  
María Manuela Reyes-Estebanez ◽  
Juan Carlos Camacho-Chab ◽  
Benjamín Otto Ortega-Morales
Keyword(s):  
Heterotrophic Bacteria ◽  
Neglected Tropical Diseases ◽  
New Drugs ◽  
Future Research ◽  
Fungal Metabolites ◽  
Lead Compounds ◽  
Current State ◽  
Causative Agents ◽  
Antiparasitic Drugs ◽  
New Generation

Trypanosomatids are the causative agents of leishmaniasis and trypanosomiasis, which affect about 20 million people in the world’s poorest countries, leading to 95,000 deaths per year. They are often associated with malnutrition, weak immune systems, low quality housing, and population migration. They are generally recognized as neglected tropical diseases. New drugs against these parasitic protozoa are urgently needed to counteract drug resistance, toxicity, and the high cost of commercially available drugs. Microbial bioprospecting for new molecules may play a crucial role in developing a new generation of antiparasitic drugs. This article reviews the current state of the available literature on chemically defined metabolites of microbial origin that have demonstrated antitrypanosomatid activity. In this review, bacterial and fungal metabolites are presented; they originate from a range of microorganisms, including cyanobacteria, heterotrophic bacteria, and filamentous fungi. We hope to provide a useful overview for future research to identify hits that may become the lead compounds needed to accelerate the discovery of new drugs against trypanosomatids.

scholarly journals PARACOCCIDIOIDOMYCOSIS TREATMENT

2015 ◽  
Vol 57 (suppl 19) ◽  
pp. 31-37 ◽  
Author(s):  
Maria Aparecida SHIKANAI-YASUDA
Keyword(s):  
Immune Response ◽  
Case Series ◽  
New Drugs ◽  
Genetic Characteristics ◽  
Treatment Regimens ◽  
Multiple Organs ◽  
Fungal Load ◽  
Immunocompromised Hosts ◽  
Host Parasite ◽  
Treatment Alternatives

SUMMARYConsidered to be an emerging endemic mycosis in Latin America, paracoccidioidomycosis is characterized by a chronic course and involvement of multiple organs in immunocompromised hosts. Infection sequelae are mainly related to pulmonary and adrenal insufficiency. The host-parasite interaction results in different expressions of the immune response depending on parasite pathogenicity, fungal load and genetic characteristics of the host. A few controlled and case series reports have shown that azoles and fast-acting sulfa derivatives are useful treatment alternatives in milder forms of the disease. For moderate/severe cases, more prolonged treatments or even parenteral routes are required especially when there is involvement of the digestive tract mucosa, resulting in poor drug absorption. Although comparative studies have reported that shorter treatment regimens with itraconazole are able to induce cure in chronically-infected patients, there are still treatment challenges such as the need for more controlled studies involving acute cases, the search for new drugs and combinations, and the search for compounds capable of modulating the immune response in severe cases as well as the paradoxical reactions.

scholarly journals Comparative Analysis of Virulence Mechanisms of Trypanosomatids Pathogenic to Humans

2021 ◽  
Vol 11 ◽  
Author(s):  
Artur Leonel de Castro Neto ◽  
José Franco da Silveira ◽  
Renato Arruda Mortara
Keyword(s):  
Immune Response ◽  
Antigenic Variation ◽  
Human Infection ◽  
Host Cells ◽  
Infection Cycle ◽  
Humoral Immune ◽  
Extracellular Milieu ◽  
The Family ◽  
Causative Agents ◽  
Variant Surface Glycoproteins

Trypanosoma brucei, Leishmania spp., and T. cruzi are flagellate protozoans of the family Trypanosomatidae and the causative agents of human African trypanosomiasis, leishmaniasis, and Chagas disease, respectively. These diseases affect humans worldwide and exert a significant impact on public health. Over the course of evolution, the parasites associated with these pathologies have developed mechanisms to circumvent the immune response system throughout the infection cycle. In cases of human infection, this function is undertaken by a group of proteins and processes that allow the parasites to propagate and survive during host invasion. In T. brucei, antigenic variation is promoted by variant surface glycoproteins and other proteins involved in evasion from the humoral immune response, which helps the parasite sustain itself in the extracellular milieu during infection. Conversely, Leishmania spp. and T. cruzi possess a more complex infection cycle, with specific intracellular stages. In addition to mechanisms for evading humoral immunity, the pathogens have also developed mechanisms for facilitating their adhesion and incorporation into host cells. In this review, the different immune evasion strategies at cellular and molecular levels developed by these human-pathogenic trypanosomatids have been discussed, with a focus on the key molecules responsible for mediating the invasion and evasion mechanisms and the effects of these molecules on virulence.

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