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1.
J Fungi (Basel) ; 10(5)2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38786693

RESUMEN

Cryptococcus neoformans is a lethal fungus that primarily affects the respiratory system and the central nervous system. One of the main virulence factors is the capsule, constituted by the polysaccharides glucuronoxylomannan (GXM) and glucuronoxylomanogalactan (GXMGal). Polysaccharides are immunomodulators. One of the target cell populations for modulation are macrophages, which are part of the first line of defense and important for innate and adaptive immunity. It has been reported that macrophages can be modulated to act as a "Trojan horse," taking phagocytosed yeasts to strategic sites or having their machinery activation compromised. The scarcity of information on canine cryptococcosis led us to assess whether the purified capsular polysaccharides from C. neoformans would be able to modulate the microbicidal action of macrophages. In the present study, we observed that the capsular polysaccharides, GXM, GXMGal, or capsule total did not induce apoptosis in the DH82 macrophage cell line. However, it was possible to demonstrate that the phagocytic activity was decreased after treatment with polysaccharides. In addition, recovered yeasts from macrophages treated with polysaccharides after phagocytosis could be cultured, showing that their viability was not altered. The polysaccharides led to a reduction in ROS production and the mRNA expression of IL-12 and IL-6. We observed that GXMGal inhibits MHC class II expression and GXM reduces ERK phosphorylation. In contrast, GXMGal and GXM were able to increase the PPAR-γ expression. Furthermore, our data suggest that capsular polysaccharides can reduce the microbicidal activity of canine macrophages DH82.

3.
Microbes Infect ; 26(3): 105261, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37984735

RESUMEN

Aspergillosis is a common fungal disease in avian species, causing high mortality in young chicks in agricultural farms and yards. It is caused by fungi belonging to the genus Aspergillus. Aspergillosis occurs by inhalation of fungal conidia, and in chickens, effective infection control relies on a rapid and large influx of heterophils to the lungs. Heterophils, upon different stimuli, release to the extracellular milieu their chromatin associated with several proteins that ensnare and kill different pathogens similarly to neutrophil extracellular traps. Here, we showed that Aspergillus fumigatus conidia and the peptidogalactomannan (PGM), isolated from the fungus cell wall, induce the release of DNA extracellular traps (DETs) in chicks' blood and lung heterophils. We demonstrated that reactive oxygen species, elastase and peptidyl arginine deiminase (PAD) were involved in DETs extrusion, the occurrence of DETs in the lungs of A. fumigatus-exposed chicks in vivo, and its role in chick survival. These results may contribute to developing more efficient tools for the therapeutic and diagnosis of aspergillosis.


Asunto(s)
Aspergilosis , Trampas Extracelulares , Animales , Aspergillus fumigatus , Pollos , Trampas Extracelulares/metabolismo , Esporas Fúngicas/metabolismo , Aspergilosis/veterinaria , Aspergilosis/metabolismo , Aspergilosis/microbiología , ADN
4.
Trop Med Infect Dis ; 7(12)2022 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-36548658

RESUMEN

Cancer and parasitic diseases, such as leishmaniasis and Chagas disease, share similarities that allow the co-development of new antiproliferative agents as a strategy to quickly track the discovery of new drugs. This strategy is especially interesting regarding tropical neglected diseases, for which chemotherapeutic alternatives are extremely outdated. We designed a series of (E)-3-aryl-5-(2-aryl-vinyl)-1,2,4-oxadiazoles based on the reported antiparasitic and anticancer activities of structurally related compounds. The synthesis of such compounds led to the development of a new, fast, and efficient strategy for the construction of a 1,2,4-oxadiazole ring on a silica-supported system under microwave irradiation. One hit compound (23) was identified during the in vitro evaluation against drug-sensitive and drug-resistant chronic myeloid leukemia cell lines (EC50 values ranging from 5.5 to 13.2 µM), Trypanosoma cruzi amastigotes (EC50 = 2.9 µM) and Leishmania amazonensis promastigotes (EC50 = 12.2 µM) and amastigotes (EC50 = 13.5 µM). In silico studies indicate a correlation between the in vitro activity and the interaction with tubulin at the colchicine binding site. Furthermore, ADMET in silico predictions indicate that the compounds possess a high druggability potential due to their physicochemical, pharmacokinetic, and toxicity profiles, and for hit 23, it was identified by multiple spectroscopic approaches that this compound binds with human serum albumin (HSA) via a spontaneous ground-state association with a moderate affinity driven by entropically and enthalpically energies into subdomain IIA (site I) without significantly perturbing the secondary content of the protein.

5.
Parasitol Int ; 79: 102180, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32860937

RESUMEN

Trypanosoma cruzi is the causative agent of Chagas disease which affects 8 million people in Latin America. The parasite possesses high capacity to evade host immune system and the available drugs to treat Chagas disease present low efficacy combined to serious side effects to patients. Therefore, the identification of alternative therapeutics is essential. Brazilian flora exhibits an immense diversity of metabolites with great potential to be developed into new drugs. We investigated the action of 2″,3″-dihydroochnaflavone a biflavonoid extracted from Luxemburgia nobilis Eichler ex Engl. (Ochnaceae) against T. cruzi (Y strain). Our experiments showed that this compound is effective against parasite epimastigote forms, presenting IC50 value of (2.5 ± 0.1) µM after 96 h of treatment. Ultrastructure alterations were also detected in treated epimastigotes especially mitochondrial enlargement at the kinetoplast region. At the concentration of 30 µM, the compound killed (61.6 ± 3.37)% of the parasite in its amastigote form. In addition, at the same concentration, the compound killed all trypamastigotes growing within murine macrophages after 7-9 days of infection. Nonetheless, the biflavonoid concentrations were harmless to murine enriched population of lymphocytes and peritoneal macrophages. These results indicate that 2″,3″- dihydroochnaflavone presents activity against T. cruzi.


Asunto(s)
Biflavonoides/farmacología , Ochnaceae/química , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Linfocitos/efectos de los fármacos , Macrófagos Peritoneales/efectos de los fármacos , Ratones , Ratones Endogámicos BALB C , Extractos Vegetales/química , Extractos Vegetales/farmacología , Pruebas de Toxicidad
6.
Artículo en Inglés | MEDLINE | ID: mdl-32596164

RESUMEN

Leishmaniasis is an anthropozoonotic disease, and dogs are considered the main urban reservoir of the parasite. Macrophages, the target cells of Leishmania sp., play an important role during infection. Although dogs have a major importance in the epidemiology of the disease, the majority of the current knowledge about Leishmania-macrophage interaction comes from murine experimental models. To assess whether the canine macrophage strain DH82 is an accurate model for the study of Leishmania interaction, we compared its infection by two species of Leishmania (Leishmania infantum and L. amazonensis) with the murine macrophage cell line (RAW264.7). Our results demonstrated that L. amazonensis survival was around 40% at 24 h of infection inside both macrophage cell lines; however, a reduction of 4.3 times in L. amazonensis infection at 48 h post-infection in RAW 264.7 macrophages was observed. The survival index of L. infantum in DH82 canine macrophages was around 3 times higher than that in RAW264.7 murine cells at 24 and 48 h post-infection; however, at 48 h a reduction in both macrophages was observed. Surprisingly at 24 h post-infection, NO and ROS production by DH82 canine cells stimulated with LPS or menadione or during Leishmania infection was minor compared to murine RAW264.7. However, basal arginase activity was higher in DH82 cells when compared to murine RAW264.7 cells. Analysis of the cytokines showed that these macrophages present a different response profile. L. infantum induced IL-12, and L. amazonensis induced IL-10 in both cell lines. However, L. infantum and L. amazonensis also induced TGF-ß in RAW 264.7. CD86 and MHC expression showed that L. amazonensis modulated them in both cell lines. Conversely, the parasite load profile did not show significant difference between both macrophage cell lines after 48 h of infection, which suggests that other mechanisms of Leishmania control could be involved in DH82 cells.


Asunto(s)
Leishmania infantum , Leishmania mexicana , Animales , Línea Celular , Perros , Macrófagos , Ratones , Ratones Endogámicos BALB C
7.
Sci Rep ; 9(1): 6247, 2019 04 18.
Artículo en Inglés | MEDLINE | ID: mdl-31000764

RESUMEN

Visceral leishmaniasis is a chronic disease that affects humans and dogs as well. Dogs, the domestic reservoir of Leishmania, play a central role in the transmission of visceral leishmaniasis, the most severe form of this disease. Neutrophils are the most abundant leukocytes in blood and interact with the parasite after infection. Here, we evaluate the effector properties of neutrophils from healthy and naturally Leishmania infantum-infected dogs. Our results showed that the parasite induced neutrophil extracellular trap (NET) release from neutrophils in both groups. Additionally, phagocytosis and NETs contributed differently to parasite killing by neutrophils from healthy and infected animals, and IFN-γ, IL-8, IL-4 and TNF-α production by neutrophils from both groups were differentially modulated by the parasite. Our results contribute to a better understanding of the complex role played by neutrophils in canine visceral leishmaniasis, which may favor the development of more effective therapies.


Asunto(s)
Leishmania infantum/patogenicidad , Leishmaniasis Visceral/veterinaria , Neutrófilos/parasitología , Animales , Enfermedades de los Perros/sangre , Enfermedades de los Perros/parasitología , Perros , Trampas Extracelulares/parasitología , Femenino , Interferón gamma/metabolismo , Interleucina-4/metabolismo , Interleucina-8/metabolismo , Leishmaniasis Visceral/sangre , Masculino , Neutrófilos/metabolismo , Fagocitosis , Factor de Necrosis Tumoral alfa/metabolismo
8.
Toxins (Basel) ; 8(11)2016 10 31.
Artículo en Inglés | MEDLINE | ID: mdl-27809242

RESUMEN

Piperine is an abundant amide extracted from black pepper seeds which has been shown to have protective effects against cytotoxic and genotoxic carcinogenesis induced by certain chemical carcinogens and aflatoxin B1 (AFB1) in vitro. The aim of this work was to study, in vivo, the antigenotoxic potential of feed-added piperine on broiler chickens experimentally intoxicated with AFB1, using micronucleus and comet assays. The antigenotoxicity assessment of 9-day-old chicks was performed on a total of 60 chickens divided into four groups of 15 broilers each: (C) control, (P) 60 mg·piperine kg-1 feed, (A) 0.5 mg·AFB1·kg-1 body weight, (daily by oral route), and (P + A) co-treatment with piperine and AFB1. The experiment was conducted for 26 days. Chicks intoxicated with AFB1 showed significant genotoxic effects in the first 24 h post intoxication, and the effects remained in the other periods analyzed (48, 72, and 96 h and 26 days of treatment). The DNA damage in peripheral blood cells, the number of erythrocytes with micronuclei, and polychromatic-to-normochromatic erythrocyte ratio were significantly reduced or absent in the piperine/AFB1 group. No significant differences were observed between the group piperine/AFB1 and the control and piperine-alone groups. The addition 60 mg·kg-1 of piperine to the diet of the broiler chicks was safe, promoting beneficial effects in poultry health with respect to the toxic effects 0.5 mg·AFB1·kg-1 body weight.


Asunto(s)
Aflatoxina B1/toxicidad , Alcaloides/farmacología , Anticarcinógenos/farmacología , Benzodioxoles/farmacología , Carcinógenos/toxicidad , Piperidinas/farmacología , Alcamidas Poliinsaturadas/farmacología , Alimentación Animal , Animales , Pollos , Ensayo Cometa , Daño del ADN , Dieta/veterinaria , Ingestión de Alimentos/efectos de los fármacos , Masculino , Pruebas de Micronúcleos , Aumento de Peso/efectos de los fármacos
9.
Antimicrob Agents Chemother ; 58(10): 6197-208, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25114129

RESUMEN

Resveratrol is a polyphenol found in black grapes and red wine and has many biological activities. In this study, we evaluated the effect of resveratrol alone and in association with amphotericin B (AMB) against Leishmania amazonensis. Our results demonstrate that resveratrol possesses both antipromastigote and antiamastigote effects, with 50% inhibitory concentrations (IC50s) of 27 and 42 µM, respectively. The association of resveratrol with AMB showed synergy for L. amazonensis amastigotes, as demonstrated by the mean sums of fractional inhibitory index concentration (mean ΣFIC) of 0.483, although for promastigotes, this association was indifferent. Treatment with resveratrol increased the percentage of promastigotes in the sub-G0/G1 phase of the cell cycle, reduced the mitochondrial potential, and showed an elevated choline peak and CH2-to-CH3 ratio in the nuclear magnetic resonance (NMR) spectroscopy analysis; all these features indicate parasite death. Resveratrol also decreased the activity of the enzyme arginase in uninfected and infected macrophages with and without stimulation with interleukin-4 (IL-4), also implicating arginase inhibition in parasite death. The anti-Leishmania effect of resveratrol and its potential synergistic association with AMB indicate that these compounds should be subjected to further studies of drug association therapy in vivo.


Asunto(s)
Anfotericina B/farmacología , Leishmania/efectos de los fármacos , Estilbenos/farmacología , Antiprotozoarios/farmacología , Biología Computacional , Sinergismo Farmacológico , Leishmania/genética , Espectroscopía de Resonancia Magnética , Resveratrol , Ristocetina/metabolismo
10.
Mem Inst Oswaldo Cruz ; 108(6): 679-85, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24037188

RESUMEN

Leishmania parasites expose phosphatidylserine (PS) on their surface, a process that has been associated with regulation of host's immune responses. In this study we demonstrate that PS exposure by metacyclic promastigotes of Leishmania amazonensis favours blood coagulation. L. amazonensis accelerates in vitro coagulation of human plasma. In addition, L. amazonensis supports the assembly of the prothrombinase complex, thus promoting thrombin formation. This process was reversed by annexin V which blocks PS binding sites. During blood meal, Lutzomyia longipalpis sandfly inject saliva in the bite site, which has a series of pharmacologically active compounds that inhibit blood coagulation. Since saliva and parasites are co-injected in the host during natural transmission, we evaluated the anticoagulant properties of sandfly saliva in counteracting the procoagulant activity of L. amazonensis . Lu. longipalpis saliva reverses plasma clotting promoted by promastigotes. It also inhibits thrombin formation by the prothrombinase complex assembled either in phosphatidylcholine (PC)/PS vesicles or in L. amazonensis . Sandfly saliva inhibits factor X activation by the intrinsic tenase complex assembled on PC/PS vesicles and blocks factor Xa catalytic activity. Altogether our results show that metacyclic promastigotes of L. amazonensis are procoagulant due to PS exposure. Notably, this effect is efficiently counteracted by sandfly saliva.


Asunto(s)
Coagulación Sanguínea/fisiología , Leishmania/metabolismo , Fosfatidilserinas/metabolismo , Psychodidae/parasitología , Saliva/metabolismo , Animales , Anticoagulantes/metabolismo , Cisteína Endopeptidasas , Factor V/antagonistas & inhibidores , Factor X/antagonistas & inhibidores , Factor Xa , Inhibidores del Factor Xa , Humanos , Insectos Vectores/parasitología , Proteínas de Neoplasias/antagonistas & inhibidores , Tiempo de Tromboplastina Parcial , Fosfatidilcolinas/metabolismo , Psychodidae/metabolismo , Trombina/antagonistas & inhibidores , Extractos de Tejidos/metabolismo
11.
Mem. Inst. Oswaldo Cruz ; 108(6): 679-685, set. 2013. graf
Artículo en Inglés | LILACS | ID: lil-685490

RESUMEN

Leishmania parasites expose phosphatidylserine (PS) on their surface, a process that has been associated with regulation of host's immune responses. In this study we demonstrate that PS exposure by metacyclic promastigotes of Leishmania amazonensis favours blood coagulation. L. amazonensis accelerates in vitro coagulation of human plasma. In addition, L. amazonensis supports the assembly of the prothrombinase complex, thus promoting thrombin formation. This process was reversed by annexin V which blocks PS binding sites. During blood meal, Lutzomyia longipalpis sandfly inject saliva in the bite site, which has a series of pharmacologically active compounds that inhibit blood coagulation. Since saliva and parasites are co-injected in the host during natural transmission, we evaluated the anticoagulant properties of sandfly saliva in counteracting the procoagulant activity of L. amazonensis . Lu. longipalpis saliva reverses plasma clotting promoted by promastigotes. It also inhibits thrombin formation by the prothrombinase complex assembled either in phosphatidylcholine (PC)/PS vesicles or in L. amazonensis . Sandfly saliva inhibits factor X activation by the intrinsic tenase complex assembled on PC/PS vesicles and blocks factor Xa catalytic activity. Altogether our results show that metacyclic promastigotes of L. amazonensis are procoagulant due to PS exposure. Notably, this effect is efficiently counteracted by sandfly saliva.


Asunto(s)
Animales , Humanos , Coagulación Sanguínea/fisiología , Leishmania/metabolismo , Fosfatidilserinas/metabolismo , Psychodidae/parasitología , Saliva/metabolismo , Anticoagulantes/metabolismo , Cisteína Endopeptidasas , Factor V/antagonistas & inhibidores , Factor X/antagonistas & inhibidores , Factor Xa/antagonistas & inhibidores , Insectos Vectores/parasitología , Proteínas de Neoplasias/antagonistas & inhibidores , Tiempo de Tromboplastina Parcial , Fosfatidilcolinas/metabolismo , Psychodidae/metabolismo , Trombina/antagonistas & inhibidores , Extractos de Tejidos/metabolismo
12.
Acta Trop ; 113(3): 269-78, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19962365

RESUMEN

Blastocrithidia culicis is a monoxenous trypanosomatid that inhabits mosquitoes. Although its life cycle in these insects has not been described, we recently demonstrated that B. culicis colonizes the Aedes aegypti digestive tract and is also able to reach the mosquito's haemocoel. In this work, we describe the interaction of B. culicis with the A. aegypti salivary gland in vitro and in vivo. Ultrastructural analysis reveals different steps of the invasion process, beginning with the insertion of the B. culicis anterior flagellum into the basal lamina of the gland and ending with the protozoan inside the salivary gland acini compartment. Carbohydrates are involved in the initial adhesion of B. culicis cells to the salivary glands, as demonstrated by protozoan binding inhibition assays and fluorescent lectin labeling of the trypanosomatid-salivary gland interaction. B. culicis is able to survive after incubation in vitro in the mosquito haemolymph, and trypanosomatid binding to salivary glands was confirmed by the injection of radioactively labeled protozoa into the mosquito haemocoel. These results suggest that salivary gland invasion could be part of the B. culicis life cycle in A. aegypti, raising the possibility that B. culicis can be transmitted by these mosquitoes.


Asunto(s)
Aedes/parasitología , Trypanosomatina/patogenicidad , Animales , Metabolismo de los Hidratos de Carbono , Adhesión Celular , Femenino , Interacciones Huésped-Patógeno , Lectinas/metabolismo , Microscopía Confocal , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Unión Proteica , Proteínas Protozoarias/metabolismo , Glándulas Salivales/parasitología , Glándulas Salivales/ultraestructura
13.
PLoS One ; 4(5): e5733, 2009 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-19478944

RESUMEN

Mimicking mammalian apoptotic cells by exposing phosphatidylserine (PS) is a strategy used by virus and parasitic protozoa to escape host protective inflammatory responses. With Leishmania amazonensis (La), apoptotic mimicry is a prerogative of the intramacrophagic amastigote form of the parasite and is modulated by the host. Now we show that differently from what happens with amastigotes, promastigotes exposing PS are non-viable, non-infective cells, undergoing apoptotic death. As part of the normal metacyclogenic process occurring in axenic cultures and in the gut of sand fly vectors, a sub-population of metacyclic promastigotes exposes PS. Apoptotic death of the purified PS-positive (PS(POS)) sub-population was confirmed by TUNEL staining and DNA laddering. Transmission electron microscopy revealed morphological alterations in PS(POS) metacyclics such as DNA condensation, cytoplasm degradation and mitochondrion and kinetoplast destruction, both in in vitro cultures and in sand fly guts. TUNEL(POS) promastigotes were detected only in the anterior midgut to foregut boundary of infected sand flies. Interestingly, caspase inhibitors modulated parasite death and PS exposure, when added to parasite cultures in a specific time window. Efficient in vitro macrophage infections and in vivo lesions only occur when PS(POS) and PS-negative (PS(NEG)) parasites were simultaneously added to the cell culture or inoculated in the mammalian host. The viable PS(NEG) promastigote was the infective form, as shown by following the fate of fluorescently labeled parasites, while the PS(POS) apoptotic sub-population inhibited host macrophage inflammatory response. PS exposure and macrophage inhibition by a subpopulation of promastigotes is a different mechanism than the one previously described with amastigotes, where the entire population exposes PS. Both mechanisms co-exist and play a role in the transmission and development of the disease in case of infection by La. Since both processes confer selective advantages to the infective microorganism they justify the occurrence of apoptotic features in a unicellular pathogen.


Asunto(s)
Apoptosis , Leishmania mexicana/citología , Leishmania mexicana/crecimiento & desarrollo , Leishmaniasis/patología , Leishmaniasis/parasitología , Estadios del Ciclo de Vida , Animales , Sistema Digestivo/citología , Sistema Digestivo/parasitología , Sistema Digestivo/ultraestructura , Etiquetado Corte-Fin in Situ , Leishmania mexicana/patogenicidad , Leishmania mexicana/ultraestructura , Ratones , Fosfatidilserinas/metabolismo , Psychodidae/citología , Psychodidae/parasitología , Psychodidae/ultraestructura
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