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Journal of Inflammation (London,... May 2024The transient receptor potential vanilloid 1 (TRPV1) is well-established in neuronal function, yet its role in immune reactions remains enigmatic. The conflicting data...
BACKGROUND
The transient receptor potential vanilloid 1 (TRPV1) is well-established in neuronal function, yet its role in immune reactions remains enigmatic. The conflicting data on its inflammatory role, suggesting both pro-inflammatory and anti-inflammatory effects upon TRPV1 stimulation in immune cells, adds complexity. To unravel TRPV1 immunomodulatory mechanisms, we investigated how the TRPV1 agonist capsaicin influences lipopolysaccharide (LPS)-induced pro-inflammatory macrophage phenotypes.
RESULTS
Changes in the surface molecules, cytokine production, and signaling cascades linked to the phenotype of M1 or M2 macrophages of the J774 macrophage cell line and bone marrow-derived macrophages, treated with capsaicin before or after the LPS-induced inflammatory reaction were determined. The functional capacity of macrophages was also assessed by infecting the stimulated macrophages with the intracellular parasite Leishmania mexicana.
CONCLUSION
Our findings reveal that TRPV1 activation yields distinct macrophage responses influenced by the inflammatory context. LPS pre-treatment followed by capsaicin activation prompted increased calcium influx, accompanied by a shift toward an anti-inflammatory M2b-like polarization state.
PubMed: 38790047
DOI: 10.1186/s12950-024-00391-0 -
Tropical Medicine and Infectious Disease May 2024Dendritic cells (DC) along with macrophages are the main host cells of the intracellular parasite . DC traverse a process of maturation, passing through an immature...
Dendritic cells (DC) along with macrophages are the main host cells of the intracellular parasite . DC traverse a process of maturation, passing through an immature state with phagocytic ability to a mature one where they can modulate the immune response through the secretion of cytokines. Several studies have demonstrated that inhibits DC maturation. Nevertheless, when cells are subjected to a second stimulus such as LPS/IFN-γ, they manage to mature. In the maturation process of DC, several signaling pathways have been implicated, importantly MAPK. On the other hand, Akt is a signaling pathway deeply involved in cell survival. Some species have shown to activate MAPK and Akt in different cells. The aim of this work was to investigate the role of ERK and Akt in the maturation of monocyte-derived DC (moDC) infected with . moDC were infected with metacyclic promastigotes, and the phosphorylation of ERK and Akt, the expression of MHCII and CD86 and IL-12 transcript, and secretion were determined in the presence or absence of an Akt inhibitor. We showed that induces a sustained Akt and ERK phosphorylation, while the Akt inhibitor inhibits it. Moreover, the infection of moDC downregulates CD86 expression but not MHCII, and the Akt inhibitor reestablishes CD86 expression and 12p40 production. Thus, can modulate DC maturation though Akt signaling.
PubMed: 38787051
DOI: 10.3390/tropicalmed9050118 -
PLoS Neglected Tropical Diseases May 2024In Brazil, Leishmania amazonensis is the etiological agent of cutaneous and diffuse cutaneous leishmaniasis. The state of Maranhão in the Northeast of Brazil is...
In Brazil, Leishmania amazonensis is the etiological agent of cutaneous and diffuse cutaneous leishmaniasis. The state of Maranhão in the Northeast of Brazil is prevalent for these clinical forms of the disease and also has high rates of HIV infection. Here, we characterized the drug susceptibility of a L. amazonensis clinical isolate from a 46-year-old man with diffuse cutaneous leishmaniasis coinfected with HIV from this endemic area. This patient underwent several therapeutic regimens with meglumine antimoniate, liposomal amphotericin B, and pentamidine, without success. In vitro susceptibility assays against promastigotes and intracellular amastigotes demonstrated that this isolate had low susceptibility to amphotericin B, when compared with the reference strain of this species that is considered susceptible to antileishmanial drugs. Additionally, we investigated whether the low in vitro susceptibility would affect the in vivo response to amphotericin B treatment. The drug was effective in reducing the lesion size and parasite burden in mice infected with the reference strain, whereas those infected with the clinical isolate and a resistant line (generated experimentally by stepwise selection) were refractory to amphotericin B treatment. To evaluate whether the isolate was intrinsically resistant to amphotericin B in animals, infected mice were treated with other drugs that had not been used in the treatment of the patient (miltefosine, paromomycin, and a combination of both). Our findings demonstrated that all drug schemes were able to reduce lesion size and parasite burden in animals infected with the clinical isolate, confirming the amphotericin B-resistance phenotype. These findings indicate that the treatment failure observed in the patient may be associated with amphotericin B resistance, and demonstrate the potential emergence of amphotericin B-resistant L. amazonensis isolates in an area of Brazil endemic for cutaneous leishmaniasis.
Topics: Amphotericin B; Animals; Brazil; Middle Aged; Antiprotozoal Agents; Humans; Male; Mice; Drug Resistance; Leishmania; Leishmania mexicana; Leishmaniasis, Cutaneous; HIV Infections; Parasitic Sensitivity Tests; Mice, Inbred BALB C; Leishmaniasis, Diffuse Cutaneous
PubMed: 38768213
DOI: 10.1371/journal.pntd.0012175 -
International Journal of Molecular... Mar 2024Twenty 2-(4-alkyloxyphenyl)-imidazolines and 2-(4-alkyloxyphenyl)-imidazoles were synthesized, with the former being synthesized in two steps by using MW and...
Twenty 2-(4-alkyloxyphenyl)-imidazolines and 2-(4-alkyloxyphenyl)-imidazoles were synthesized, with the former being synthesized in two steps by using MW and ultrasonication energy, resulting in good to excellent yields. Imidazoles were obtained in moderate yields by oxidizing imidazolines with MnO and MW energy. In response to the urgent need to treat neglected tropical diseases, a set of 2-(4-alkyloxyphenyl)- imidazolines and imidazoles was tested in vitro on and . The leishmanicidal activity of ten compounds was evaluated, showing an IC < 10 µg/mL. Among these compounds, - were the most active, with IC values < 1 µg/mL (similar to the reference drugs). In the evaluation on epimastigotes of , only and reached an IC < 1 µg/mL, showing better inhibition than both reference drugs. However, compounds , , and also demonstrated attractive trypanocidal activities, with IC values < 10 µg/mL, similar to the values for benznidazole and nifurtimox.
Topics: Humans; Imidazoles; Imidazolines; Trypanosoma cruzi; Leishmania mexicana; Manganese Compounds; Oxides; Antiprotozoal Agents; Chagas Disease
PubMed: 38612484
DOI: 10.3390/ijms25073673 -
Molecular and Biochemical Parasitology Jun 2024In eukaryotic cells, molecular fate and cellular responses are shaped by multicomponent enzyme systems which reversibly attach ubiquitin and ubiquitin-like modifiers to...
In eukaryotic cells, molecular fate and cellular responses are shaped by multicomponent enzyme systems which reversibly attach ubiquitin and ubiquitin-like modifiers to target proteins. The extent of the ubiquitin proteasome system in Leishmania mexicana and its importance for parasite survival has recently been established through deletion mutagenesis and life-cycle phenotyping studies. The ubiquitin conjugating E2 enzyme UBC2, and the E2 enzyme variant UEV1, with which it forms a stable complex in vitro, were shown to be essential for the differentiation of promastigote parasites to the infectious amastigote form. To investigate further, we used immunoprecipitation of Myc-UBC2 or Myc-UEV1 to identify interacting proteins in L. mexicana promastigotes. The interactome of UBC2 comprises multiple ubiquitin-proteasome components including UEV1 and four RING E3 ligases, as well as potential substrates predicted to have roles in carbohydrate metabolism and intracellular trafficking. The smaller UEV1 interactome comprises six proteins, including UBC2 and shared components of the UBC2 interactome consistent with the presence of intracellular UBC2-UEV1 complexes. Recombinant RING1, RING2 and RING4 E3 ligases were shown to support ubiquitin transfer reactions involving the E1, UBA1a, and UBC2 to available substrate proteins or to unanchored ubiquitin chains. These studies define additional components of a UBC2-dependent ubiquitination pathway shown previously to be essential for promastigote to amastigote differentiation.
Topics: Ubiquitin-Conjugating Enzymes; Ubiquitin-Protein Ligases; Protozoan Proteins; Leishmania mexicana; Protein Binding; Protein Interaction Mapping; Immunoprecipitation
PubMed: 38556171
DOI: 10.1016/j.molbiopara.2024.111619 -
Vaccines Mar 2024Immunization with various species lacking induces robust immunity against a homologous and heterologous virulent challenge, making mutants a putative candidate for a...
Immunization with various species lacking induces robust immunity against a homologous and heterologous virulent challenge, making mutants a putative candidate for a leishmaniasis vaccine. Centrin is a calcium-binding cytoskeletal protein involved in centrosome duplication in higher eukaryotes and spp. lacking centrin are unable to replicate and are non-pathogenic. We developed a -deficient () cell line and confirmed its impaired survival following phagocytosis by macrophages. Upon experimental inoculation into BALB/c mice, failed to induce lesions and parasites were rapidly eliminated. The immune response following inoculation with was characterized by a mixed IFN-γ, IL-4, and IL-10 response and did not confer protection against infection, distinct from , , and centrin-deficient mutants. A prime-boost strategy also did not lead to a protective immune response against homologous challenge. On the contrary, immunization with -deficient () cross-protected against challenge, illustrating the ability of to induce the Th1-dominant protective immunity needed for leishmaniasis control. In conclusion, while deficiency in causes attenuation of virulence, and disrupts the ability to cause disease, it fails to stimulate a protective immune response.
PubMed: 38543944
DOI: 10.3390/vaccines12030310 -
Parasitology Apr 2024is a trypanosomatid parasite that causes skin lesions in its cutaneous form. Current therapies rely on old and expensive drugs, against which the parasites have...
is a trypanosomatid parasite that causes skin lesions in its cutaneous form. Current therapies rely on old and expensive drugs, against which the parasites have acquired considerable resistance. Trypanosomatids are unable to synthesize purines relying on salvaging from the host, and nucleoside analogues have emerged as attractive antiparasitic drug candidates. 4-Methyl-7-β-D-ribofuranosyl-7H-pyrrolo[2,3-d]pyrimidine (CL5564), an analogue of tubercidin in which the amine has been replaced by a methyl group, demonstrates activity against and . Herein, we investigated its and activity against . CL5564 was 6.5-fold ( = 0.0002) more potent than milteforan™ (ML) against intracellular forms in peritoneal mouse macrophages, and highly selective, while combination with ML gave an additive effect. These results stimulated us to study the activity of CL5564 in mouse model of cutaneous Leishmania infection. BALB/c female and male mice infected by treated with CL5564 (10 mg kg, intralesional route for five days) presented a >93% reduction of paw lesion size likely ML given orally at 40 mg kg, while the combination (10 + 40 mg kg of CL5564 and ML, respectively) caused >96% reduction. The qPCR confirmed the suppression of parasite load, but only the combination approach reached 66% of parasitological cure. These results support additional studies with nucleoside derivatives.
Topics: Animals; Leishmaniasis, Cutaneous; Mice, Inbred BALB C; Mice; Female; Male; Leishmania mexicana; Disease Models, Animal; Tubercidin; Antiprotozoal Agents; Macrophages, Peritoneal; Leishmania
PubMed: 38533610
DOI: 10.1017/S0031182024000362 -
International Journal For Parasitology.... Apr 2024Leishmaniasis and Chagas disease are parasitic infections that affect millions of people worldwide, producing thousands of deaths per year. The current treatments...
Leishmaniasis and Chagas disease are parasitic infections that affect millions of people worldwide, producing thousands of deaths per year. The current treatments against these pathologies are not totally effective and produce some side effects in the patients. Acrylonitrile derivatives are a group of compounds that have shown activity against these two diseases. In this work, four novels synthetic acrylonitriles were evaluated against the intracellular form and extracellular forms of L. amazonensis and T. cruzi. The compounds 2 and 3 demonstrate to have good selectivity indexes against both parasites, specifically the compound 3 against the amastigote form (SI = 6 against L. amazonensis and SI = 7.4 against T. cruzi). In addition, the parasites treated with these two compounds demonstrate to produce a programmed cell death, since they were positive for the events studied related to this type of death, including chromatin condensation, accumulation of reactive oxygen species and alteration of the mitochondrial membrane potential. In conclusion, this work confirms that acrylonitriles is a source of possible new compounds against kinetoplastids, however, more studies are needed to corroborate this activity.
Topics: Humans; Trypanosoma cruzi; Antiprotozoal Agents; Acrylonitrile; Leishmania mexicana; Chagas Disease; Cell Death
PubMed: 38484645
DOI: 10.1016/j.ijpddr.2024.100531 -
Genome Biology and Evolution Mar 2024Isocitrate dehydrogenase is an enzyme converting isocitrate to α-ketoglutarate in the canonical tricarboxylic acid (TCA) cycle. There are three different types of...
Isocitrate dehydrogenase is an enzyme converting isocitrate to α-ketoglutarate in the canonical tricarboxylic acid (TCA) cycle. There are three different types of isocitrate dehydrogenase documented in eukaryotes. Our study points out the complex evolutionary history of isocitrate dehydrogenases across kinetoplastids, where the common ancestor of Trypanosomatidae and Bodonidae was equipped with two isoforms of the isocitrate dehydrogenase enzyme: the NADP+-dependent isocitrate dehydrogenase 1 with possibly dual localization in the cytosol and mitochondrion and NADP+-dependent mitochondrial isocitrate dehydrogenase 2. In the extant trypanosomatids, isocitrate dehydrogenase 1 is present only in a few species suggesting that it was lost upon separation of Trypanosoma spp. and replaced by the mainly NADP+-dependent cytosolic isocitrate dehydrogenase 3 of bacterial origin in all the derived lineages. In this study, we experimentally demonstrate that the omnipresent isocitrate dehydrogenase 2 has a dual localization in both mitochondrion and cytosol in at least four species that possess only this isoform. The apparent lack of the NAD+-dependent isocitrate dehydrogenase activity in trypanosomatid mitochondrion provides further support to the existence of the noncanonical TCA cycle across trypanosomatids and the bidirectional activity of isocitrate dehydrogenase 3 when operating with NADP+ cofactor instead of NAD+. This observation can be extended to all 17 species analyzed in this study, except for Leishmania mexicana, which showed only low isocitrate dehydrogenase activity in the cytosol. The variability in isocitrate oxidation capacity among species may reflect the distinct metabolic strategies and needs for reduced cofactors in particular environments.
Topics: Isocitrate Dehydrogenase; Isocitrates; NADP; NAD; Protein Isoforms
PubMed: 38447055
DOI: 10.1093/gbe/evae042 -
JACS Au Feb 2024Visceral leishmaniasis and Chagas disease are neglected tropical diseases (NTDs) that severely impact the developing world. With current therapies suffering from poor...
Visceral leishmaniasis and Chagas disease are neglected tropical diseases (NTDs) that severely impact the developing world. With current therapies suffering from poor efficacy and safety profiles as well as emerging resistance, new drug leads are direly needed. In this work, 26 alkaloids (9 natural and 17 synthetic) belonging to the benzyltetrahydroisoquinoline (BI) family were evaluated against both the pro/trypomastigote and amastigote forms of the parasites and , the causative agents of these diseases. These alkaloids were synthesized via an efficient and modular enantioselective approach based on Bischler-Napieralski cyclization/Noyori asymmetric transfer hydrogenation to build the tetrahydroisoquinoline core. The bis-benzyltetrahydroisoquinoline (BBI) alkaloids were prepared using an Ullmann coupling of two BI units to form the biaryl ether linkage, which enabled a comprehensive survey of the influence of BI stereochemistry on bioactivity. Preliminary studies into the mechanism of action against demonstrate that these compounds interfere with the cell cycle, potentially through inhibition of kinetoplast division, which may offer opportunities to identify a new target/mechanism of action. Three of the synthesized alkaloids showed promising druglike potential, meeting the Drugs for Neglected Disease (DND) criteria for a hit against Chagas disease.
PubMed: 38425909
DOI: 10.1021/jacsau.4c00007