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1.
Open Biol ; 14(9): 240128, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39255848

RESUMO

Cilia are antenna-like organelles protruding from the surface of many cell types in the human body. Defects in ciliary structure or function often lead to diseases that are collectively called ciliopathies. Cilia and flagella-associated protein 410 (CFAP410) localizes at the basal body of cilia/flagella and plays essential roles in ciliogenesis, neuronal development and DNA damage repair. It remains unknown how its specific basal body location is achieved. Multiple single amino acid mutations in CFAP410 have been identified in patients with various ciliopathies. One of the mutations, L224P, is located in the C-terminal domain (CTD) of human CFAP410 and causes severe spondylometaphyseal dysplasia, axial (SMDAX). However, the molecular mechanism for how the mutation causes the disorder remains unclear. Here, we report our structural studies on the CTD of CFAP410 from three distantly related organisms, Homo sapiens, Trypanosoma brucei and Chlamydomonas reinhardtii. The crystal structures reveal that the three proteins all adopt the same conformation as a tetrameric helical bundle. Our work further demonstrates that the tetrameric assembly of the CTD is essential for the correct localization of CFAP410 in T. brucei, as the L224P mutation that disassembles the tetramer disrupts its basal body localization. Taken together, our studies reveal that the basal body localization of CFAP410 is controlled by the CTD and provide a mechanistic explanation for how the mutation L224P in CFAP410 causes ciliopathies in humans.


Assuntos
Corpos Basais , Trypanosoma brucei brucei , Corpos Basais/metabolismo , Humanos , Trypanosoma brucei brucei/metabolismo , Trypanosoma brucei brucei/genética , Modelos Moleculares , Chlamydomonas reinhardtii/genética , Chlamydomonas reinhardtii/metabolismo , Cílios/metabolismo , Cristalografia por Raios X , Mutação , Sequência de Aminoácidos , Multimerização Proteica , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/química
2.
Sci Rep ; 14(1): 21295, 2024 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-39266600

RESUMO

Recently, the growth of consumer demand for functional foods with potential nutritional and health benefits led to rapid growth of analytical tools for profiling of bioactive metabolites and assure quality. Bee propolis is one of the most important bee products owing to its myriad health value. As a gummy exudate produced in beehives after harvesting from different plant species, bee propolis contains bioactive secondary metabolites. The current study aims to profiling the chemical composition of propolis samples from Nigeria using HPLC-UV-ELSD and with the aid of NMR-based analysis for assignment of metabolites classes abundant in Nigerian propolis. Red Nigerian propolis samples were subjected to phytochemical analysis using HPLC-UV-ELSD and NMR. Further chromatographic separation of promising fractions was performed by column chromatography and size exclusion chromatography. Screening of the antitrypanosomal and cytotoxic activities against Trypanosoma brucei and human leukemia cell lines (U937), respectively, was performed. The performance of LC-MS permitted identification of the different components from which 13 compound were identified and allowed combination of fractions to afford 9 fractions from which two isoflavonoids were isolated and identified using 1D and 2D NMR analysis with MS as isosativan and Medicarpin. Red Nigerian propolis crude extract showed the highest inhibitory activity at 6.5 µg/ml compared to moderate activity for the isolated compounds with MIC of 7.6 µg/ml and 12.1 µg/ml for medicarpin and isosativan, respectively. Moreover, the fraction RN-6 from the total extract showed the potent cytotoxic effect with IC50 = 26.5 µg/ml compared to standard diminazen which showed IC50 = 29.5 µg/ml.


Assuntos
Antiprotozoários , Flavonoides , Compostos Fitoquímicos , Própole , Trypanosoma brucei brucei , Própole/química , Própole/farmacologia , Antiprotozoários/farmacologia , Antiprotozoários/química , Humanos , Trypanosoma brucei brucei/efeitos dos fármacos , Flavonoides/química , Flavonoides/farmacologia , Flavonoides/análise , Compostos Fitoquímicos/farmacologia , Compostos Fitoquímicos/química , Nigéria , Animais , Cromatografia Líquida de Alta Pressão , Linhagem Celular Tumoral , Espectroscopia de Ressonância Magnética , Abelhas
3.
J Antimicrob Chemother ; 79(9): 2251-2258, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-38980760

RESUMO

BACKGROUND: Acanthamoeba spp. is the causative agent of Acanthamoeba keratitis and granulomatous amoebic encephalitis. Strathclyde minor groove binders (S-MGBs) are a promising new class of anti-infective agent that have been shown to be effective against many infectious organisms. OBJECTIVES: To synthesize and evaluate the anti-Acanthamoeba activity of a panel of S-MGBs, and therefore determine the potential of this class for further development. METHODS: A panel of 12 S-MGBs was synthesized and anti-Acanthamoeba activity was determined using an alamarBlue™-based trophocidal assay against Acanthamoeba castellanii. Cross-screening against Trypanosoma brucei brucei, Staphylococcus aureus and Escherichia coli was used to investigate selective potency. Cytotoxicity against HEK293 cells allowed for selective toxicity to be measured. DNA binding studies were carried out using native mass spectrometry and DNA thermal shift assays. RESULTS AND DISCUSSION: S-MGB-241 has an IC50 of 6.6 µM against A. castellanii, comparable to the clinically used miltefosine (5.6 µM) and negligible activity against the other organisms. It was also found to have an IC50 > 100 µM against HEK293 cells, demonstrating low cytotoxicity. S-MGB-241 binds to DNA as a dimer, albeit weakly compared to other S-MGBs previously studied. This was confirmed by DNA thermal shift assay with a ΔTm = 1 ±â€Š0.1°C. CONCLUSIONS: Together, these data provide confidence that S-MGBs can be further optimized to generate new, potent treatments for Acanthameoba spp. infections. In particular, S-MGB-241, has been identified as a 'hit' compound that is selectively active against A. castellanii, providing a starting point from which to begin optimization of DNA binding and potency.


Assuntos
Acanthamoeba castellanii , Acanthamoeba castellanii/efeitos dos fármacos , Humanos , Células HEK293 , Escherichia coli/efeitos dos fármacos , Antiprotozoários/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Testes de Sensibilidade Parasitária , Sobrevivência Celular/efeitos dos fármacos
4.
Nucleic Acids Res ; 52(17): 10645-10653, 2024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-39011881

RESUMO

RNA methylation adjacent to the 5' cap plays a critical role in controlling mRNA stability and protein synthesis. In trypanosomes the 5'-terminus of mRNA is protected by hypermethylated cap 4. Trypanosomes encode a cytoplasmic recapping enzyme TbCe1 which possesses an RNA kinase and guanylyltransferase activities that can convert decapped 5'-monophosphate-terminated pRNA into GpppRNA. Here, we demonstrated that the RNA kinase activity is stimulated by two orders of magnitude on a hypermethylated pRNA derived from cap 4. The N6, N6-2'-O trimethyladenosine modification on the first nucleotide was primarily accountable for enhancing both the RNA kinase and the guanylyltransferase activity of TbCe1. In contrast, N6 methyladenosine severely inhibits the guanylyltransferase activity of the mammalian capping enzyme. Furthermore, we showed that TbCmt1 cap (guanine N7) methyltransferase was localized in the cytoplasm, and its activity was also stimulated by hypermethylation at 2'-O ribose, suggesting that TbCe1 and TbCmt1 act together as a recapping enzyme to regenerate translatable mRNA from decapped mRNA. Our result establishes the functional role of cap 4 hypermethylation in recruitment and activation of mRNA recapping pathway. Methylation status at the 5'-end of transcripts could serve as a chemical landmark to selectively regulate the level of functional mRNA by recapping enzymes.


Assuntos
Nucleotidiltransferases , Proteínas de Protozoários , Capuzes de RNA , RNA Mensageiro , Trypanosoma brucei brucei , Capuzes de RNA/metabolismo , Capuzes de RNA/genética , Trypanosoma brucei brucei/genética , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Metilação , Nucleotidiltransferases/metabolismo , Nucleotidiltransferases/genética , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Metiltransferases/metabolismo , Metiltransferases/genética , Citoplasma/metabolismo , Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/genética
5.
Mol Biol Cell ; 35(9): br16, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39024276

RESUMO

The outer dynein arm (ODA) is a large, multimeric protein complex essential for ciliary motility. The composition and assembly of ODA are best characterized in the green algae Chlamydomonas reinhardtii, where individual ODA subunits are synthesized and preassembled into a mature complex in the cytosol prior to ciliary import. The single-cellular parasite Trypanosoma brucei contains a motile flagellum essential for cell locomotion and pathogenesis. Similar to human motile cilia, T. brucei flagellum contains a two-headed ODA complex arranged at 24 nm intervals along the axonemal microtubule doublets. The subunit composition and the preassembly of the ODA complex in T. brucei, however, have not been investigated. In this study, we affinity-purified the ODA complex from T. brucei cytoplasmic extract. Proteomic analyses revealed the presence of two heavy chains (ODAα and ODAß), two intermediate chains (IC1and IC2) and several light chains. We showed that both heavy chains and both intermediate chains are indispensable for flagellar ODA assembly. Our study also provided biochemical evidence supporting the presence of a cytoplasmic, preassembly pathway for T. brucei ODA.


Assuntos
Axonema , Citoplasma , Dineínas , Flagelos , Proteínas de Protozoários , Trypanosoma brucei brucei , Trypanosoma brucei brucei/metabolismo , Flagelos/metabolismo , Citoplasma/metabolismo , Axonema/metabolismo , Dineínas/metabolismo , Proteínas de Protozoários/metabolismo , Microtúbulos/metabolismo , Proteômica/métodos , Cílios/metabolismo
6.
Mol Biol Cell ; 35(8): ar106, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-38865178

RESUMO

Outer dynein arms (ODAs) are responsible for ciliary beating in eukaryotes. They are assembled in the cytoplasm and shipped by intraflagellar transport (IFT) before attachment to microtubule doublets via the docking complex. The LRRC56 protein has been proposed to contribute to ODAs maturation. Mutations or deletion of the LRRC56 gene lead to reduced ciliary motility in all species investigated so far, but with variable impact on dynein arm presence. Here, we investigated the role of LRRC56 in the protist Trypanosoma brucei, where its absence results in distal loss of ODAs, mostly in growing flagella. We show that LRRC56 is a transient cargo of IFT trains during flagellum construction and surprisingly, is required for efficient attachment of a subset of docking complex proteins present in the distal portion of the organelle. This relation is interdependent since the knockdown of the distal docking complex prevents LRRC56's association with the flagellum. Intriguingly, lrrc56-/- cells display shorter flagella whose maturation is delayed. Inhibition of cell division compensates for the distal ODAs absence thanks to the redistribution of the proximal docking complex, restoring ODAs attachment but not the flagellum length phenotype. This work reveals an unexpected connection between LRRC56 and the docking complex.


Assuntos
Dineínas , Flagelos , Proteínas de Protozoários , Trypanosoma brucei brucei , Trypanosoma brucei brucei/metabolismo , Flagelos/metabolismo , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Dineínas/metabolismo , Microtúbulos/metabolismo , Cílios/metabolismo , Transporte Biológico/fisiologia , Axonema/metabolismo
7.
Inorg Chem ; 63(25): 11667-11687, 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38860314

RESUMO

Human African trypanosomiasis (HAT, sleeping sickness) and American trypanosomiasis (Chagas disease) are endemic zoonotic diseases caused by genomically related trypanosomatid protozoan parasites (Trypanosoma brucei and Trypanosoma cruzi, respectively). Just a few old drugs are available for their treatment, with most of them sharing poor safety, efficacy, and pharmacokinetic profiles. Only fexinidazole has been recently incorporated into the arsenal for the treatment of HAT. In this work, new multifunctional Ru(II) ferrocenyl compounds were rationally designed as potential agents against these pathogens by including in a single molecule 1,1'-bis(diphenylphosphino)ferrocene (dppf) and two bioactive bidentate ligands: pyridine-2-thiolato-1-oxide ligand (mpo) and polypyridyl ligands (NN). Three [Ru(mpo)(dppf)(NN)](PF6) compounds and their derivatives with chloride as a counterion were synthesized and fully characterized in solid state and solution. They showed in vitro activity on bloodstream T. brucei (EC50 = 31-160 nM) and on T. cruzi trypomastigotes (EC50 = 190-410 nM). Compounds showed the lowest EC50 values on T. brucei when compared to the whole set of metal-based compounds previously developed by us. In addition, several of the Ru compounds showed good selectivity toward the parasites, particularly against the highly proliferative bloodstream form of T. brucei. Interaction with DNA and generation of reactive oxygen species (ROS) were ruled out as potential targets and modes of action of the Ru compounds. Biochemical assays and in silico analysis led to the insight that they are able to inhibit the NADH-dependent fumarate reductase from T. cruzi. One representative hit induced a mild oxidation of low molecular weight thiols in T. brucei. The compounds were stable for at least 72 h in two different media and more lipophilic than both bioactive ligands, mpo and NN. An initial assessment of the therapeutic efficacy of one of the most potent and selective candidates, [Ru(mpo)(dppf)(bipy)]Cl, was performed using a murine infection model of acute African trypanosomiasis. This hit compound lacks acute toxicity when applied to animals in the dose/regimen described, but was unable to control parasite proliferation in vivo, probably because of its rapid clearance or low biodistribution in the extracellular fluids. Future studies should investigate the pharmacokinetics of this compound in vivo and involve further research to gain deeper insight into the mechanism of action of the compounds.


Assuntos
Compostos Ferrosos , Rutênio , Tripanossomicidas , Trypanosoma cruzi , Compostos Ferrosos/química , Compostos Ferrosos/farmacologia , Compostos Ferrosos/síntese química , Trypanosoma cruzi/efeitos dos fármacos , Ligantes , Tripanossomicidas/farmacologia , Tripanossomicidas/química , Tripanossomicidas/síntese química , Animais , Rutênio/química , Rutênio/farmacologia , Camundongos , Metalocenos/química , Metalocenos/farmacologia , Metalocenos/síntese química , Trypanosoma brucei brucei/efeitos dos fármacos , Testes de Sensibilidade Parasitária , Estrutura Molecular , Compostos Organometálicos/farmacologia , Compostos Organometálicos/química , Compostos Organometálicos/síntese química , Complexos de Coordenação/farmacologia , Complexos de Coordenação/química , Complexos de Coordenação/síntese química
8.
Structure ; 32(7): 930-940.e3, 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38593794

RESUMO

3-Methylcrotonyl-CoA carboxylase (MCC) catalyzes the two-step, biotin-dependent production of 3-methylglutaconyl-CoA, an essential intermediate in leucine catabolism. Given the critical metabolic role of MCC, deficiencies in this enzyme lead to organic aciduria, while its overexpression is linked to tumor development. MCC is a dodecameric enzyme composed of six copies of each α- and ß-subunit. We present the cryo-EM structure of the endogenous MCC holoenzyme from Trypanosoma brucei in a non-filamentous state at 2.4 Å resolution. Biotin is covalently bound to the biotin carboxyl carrier protein domain of α-subunits and positioned in a non-canonical pocket near the active site of neighboring ß-subunit dimers. Moreover, flexibility of key residues at α-subunit interfaces and loops enables pivoting of α-subunit trimers to partly reduce the distance between α- and ß-subunit active sites, required for MCC catalysis. Our results provide a structural framework to understand the enzymatic mechanism of eukaryotic MCCs and to assist drug discovery against trypanosome infections.


Assuntos
Carbono-Carbono Ligases , Domínio Catalítico , Microscopia Crioeletrônica , Proteínas de Protozoários , Trypanosoma brucei brucei , Acetil-CoA Carboxilase , Carbono-Carbono Ligases/metabolismo , Carbono-Carbono Ligases/química , Carbono-Carbono Ligases/genética , Ácido Graxo Sintase Tipo II , Holoenzimas/química , Holoenzimas/metabolismo , Modelos Moleculares , Ligação Proteica , Multimerização Proteica , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Trypanosoma brucei brucei/enzimologia , Trypanosoma brucei brucei/metabolismo
9.
J Med Chem ; 67(9): 7158-7175, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38651522

RESUMO

Inhibition of hypoxanthine-guanine-xanthine phosphoribosyltransferase activity decreases the pool of 6-oxo and 6-amino purine nucleoside monophosphates required for DNA and RNA synthesis, resulting in a reduction in cell growth. Therefore, inhibitors of this enzyme have potential to control infections, caused by Plasmodium falciparum and Plasmodium vivax, Trypanosoma brucei, Mycobacterium tuberculosis, and Helicobacter pylori. Five compounds synthesized here that contain a purine base covalently linked by a prolinol group to one or two phosphonate groups have Ki values ranging from 3 nM to >10 µM, depending on the structure of the inhibitor and the biological origin of the enzyme. X-ray crystal structures show that, on binding, these prolinol-containing inhibitors stimulated the movement of active site loops in the enzyme. Against TBr in cell culture, a prodrug exhibited an EC50 of 10 µM. Thus, these compounds are excellent candidates for further development as drug leads against infectious diseases as well as being potential anticancer agents.


Assuntos
Desenho de Fármacos , Inibidores Enzimáticos , Pentosiltransferases , Pentosiltransferases/antagonistas & inibidores , Pentosiltransferases/metabolismo , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/síntese química , Relação Estrutura-Atividade , Cristalografia por Raios X , Humanos , Modelos Moleculares , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/enzimologia , Estrutura Molecular , Domínio Catalítico
10.
Biomol NMR Assign ; 18(1): 15-25, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38453826

RESUMO

KKT4 is a multi-domain kinetochore protein specific to kinetoplastids, such as Trypanosoma brucei. It lacks significant sequence similarity to known kinetochore proteins in other eukaryotes. Our recent X-ray structure of the C-terminal region of KKT4 shows that it has a tandem BRCT (BRCA1 C Terminus) domain fold with a sulfate ion bound in a typical binding site for a phosphorylated serine or threonine. Here we present the 1H, 13C and 15N resonance assignments for the BRCT domain of KKT4 (KKT4463-645) from T. brucei. We show that the BRCT domain can bind phosphate ions in solution using residues involved in sulfate ion binding in the X-ray structure. We have used these assignments to characterise the secondary structure and backbone dynamics of the BRCT domain in solution. Mutating the residues involved in phosphate ion binding in T. brucei KKT4 BRCT results in growth defects confirming the importance of the BRCT phosphopeptide-binding activity in vivo. These results may facilitate rational drug design efforts in the future to combat diseases caused by kinetoplastid parasites.


Assuntos
Cinetocoros , Ressonância Magnética Nuclear Biomolecular , Domínios Proteicos , Trypanosoma brucei brucei , Cinetocoros/metabolismo , Cinetocoros/química , Sequência de Aminoácidos , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismo , Estrutura Secundária de Proteína
11.
PLoS Negl Trop Dis ; 18(2): e0012007, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38394337

RESUMO

Trypanosoma brucei is a causative agent of the Human and Animal African Trypanosomiases. The mammalian stage parasites infect various tissues and organs including the bloodstream, central nervous system, skin, adipose tissue and lungs. They rely on ATP produced in glycolysis, consuming large amounts of glucose, which is readily available in the mammalian host. In addition to glucose, glycerol can also be used as a source of carbon and ATP and as a substrate for gluconeogenesis. However, the physiological relevance of glycerol-fed gluconeogenesis for the mammalian-infective life cycle forms remains elusive. To demonstrate its (in)dispensability, first we must identify the enzyme(s) of the pathway. Loss of the canonical gluconeogenic enzyme, fructose-1,6-bisphosphatase, does not abolish the process hence at least one other enzyme must participate in gluconeogenesis in trypanosomes. Using a combination of CRISPR/Cas9 gene editing and RNA interference, we generated mutants for four enzymes potentially capable of contributing to gluconeogenesis: fructose-1,6-bisphoshatase, sedoheptulose-1,7-bisphosphatase, phosphofructokinase and transaldolase, alone or in various combinations. Metabolomic analyses revealed that flux through gluconeogenesis was maintained irrespective of which of these genes were lost. Our data render unlikely a previously hypothesised role of a reverse phosphofructokinase reaction in gluconeogenesis and preclude the participation of a novel biochemical pathway involving transaldolase in the process. The sustained metabolic flux in gluconeogenesis in our mutants, including a triple-null strain, indicates the presence of a unique enzyme participating in gluconeogenesis. Additionally, the data provide new insights into gluconeogenesis and the pentose phosphate pathway, and improve the current understanding of carbon metabolism of the mammalian-infective stages of T. brucei.


Assuntos
Gluconeogênese , Trypanosoma brucei brucei , Animais , Humanos , Gluconeogênese/genética , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/metabolismo , Transaldolase/metabolismo , Glicerol/metabolismo , Glucose/metabolismo , Fosfofrutoquinases/metabolismo , Carbono/metabolismo , Trifosfato de Adenosina/metabolismo , Mamíferos
12.
Arch Pharm (Weinheim) ; 357(6): e2300319, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38396284

RESUMO

Several quinoline derivatives incorporating arylnitro and aminochalcone moieties were synthesized and evaluated in vitro against a broad panel of trypanosomatid protozoan parasites responsible for sleeping sickness (Trypanosoma brucei rhodesiense), nagana (Trypanosoma brucei brucei), Chagas disease (Trypanosoma cruzi), and leishmaniasis (Leishmania infantum). Several of the compounds demonstrated significant antiprotozoal activity. Specifically, compounds 2c, 2d, and 4i displayed submicromolar activity against T. b. rhodesiense with half-maximal effective concentration (EC50) values of 0.68, 0.8, and 0.19 µM, respectively, and with a high selectivity relative to human lung fibroblasts and mouse primary macrophages (∼100-fold). Compounds 2d and 4i also showed considerable activity against T. b. brucei with EC50 values of 1.4 and 0.4 µM, respectively.


Assuntos
Antiprotozoários , Leishmania infantum , Testes de Sensibilidade Parasitária , Quinolinas , Trypanosoma brucei rhodesiense , Trypanosoma cruzi , Animais , Camundongos , Quinolinas/farmacologia , Quinolinas/síntese química , Quinolinas/química , Humanos , Relação Estrutura-Atividade , Leishmania infantum/efeitos dos fármacos , Antiprotozoários/farmacologia , Antiprotozoários/síntese química , Antiprotozoários/química , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Estrutura Molecular , Trypanosoma brucei brucei/efeitos dos fármacos , Relação Dose-Resposta a Droga , Macrófagos/efeitos dos fármacos , Macrófagos/parasitologia , Fibroblastos/efeitos dos fármacos
13.
Eur J Med Chem ; 263: 115954, 2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-37984297

RESUMO

Human African Trypanosomiasis (HAT), caused by Trypanosoma brucei gambiense and rhodesiense, is a parasitic disease endemic to sub-Saharan Africa. Untreated cases of HAT can be severely debilitating and fatal. Although the number of reported cases has decreased progressively over the last decade, the number of effective and easily administered medications is very limited. In this work, we report the antitrypanosomal activity of a series of potent compounds. A subset of molecules in the series are highly selective for trypanosomes and are metabolically stable. One of the compounds, (E)-N-(4-(methylamino)-4-oxobut-2-en-1-yl)-5-nitrothiophene-2-carboxamide (10), selectively inhibited the growth of T. b. brucei, T. b. gambiense and T. b. rhodesiense, have excellent oral bioavailability and was effective in treating acute infection of HAT in mouse models. Based on its excellent bioavailability, compound 10 and its analogs are candidates for lead optimization and pre-clinical investigations.


Assuntos
Tripanossomicidas , Trypanosoma brucei brucei , Tripanossomíase Africana , Animais , Camundongos , Humanos , Trypanosoma brucei rhodesiense , Tripanossomicidas/farmacologia , Tripanossomicidas/uso terapêutico , Tripanossomíase Africana/tratamento farmacológico , Tripanossomíase Africana/parasitologia , Trypanosoma brucei gambiense
14.
Molecules ; 28(23)2023 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-38067459

RESUMO

Bis(indolyl)methanes (BIMs) are a class of compounds that have been recognized as an important core in the design of drugs with important pharmacological properties, such as promising anticancer and antiparasitic activities. Here, we explored the biological activity of the BIM core functionalized with different (hetero)aromatic moieties. We synthesized substituted BIM derivatives with triphenylamine, N,N-dimethyl-1-naphthylamine and 8-hydroxylquinolyl groups, studied their photophysical properties and evaluated their in vitro antiproliferative and antiparasitic activities. The triphenylamine BIM derivative 2a displayed an IC50 of 3.21, 3.30 and 3.93 µM against Trypanosoma brucei, Leishmania major and HT-29 cancer cell line, respectively. The selectivity index demonstrated that compound 2a was up to eight-fold more active against the parasites and HT-29 than against the healthy cell line MRC-5. Fluorescence microscopy studies with MRC-5 cells and T. brucei parasites incubated with derivative 2a indicate that the compound seems to accumulate in the cell's mitochondria and in the parasite's nucleus. In conclusion, the BIM scaffold functionalized with the triphenylamine moiety proved to be the most promising antiparasitic and anticancer agent of this series.


Assuntos
Antineoplásicos , Neoplasias , Trypanosoma brucei brucei , Humanos , Antiparasitários/farmacologia , Metano , Antineoplásicos/farmacologia , Relação Estrutura-Atividade
15.
Elife ; 122023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38126364

RESUMO

Why does protein kinase A respond to purine nucleosides in certain pathogens, but not to the cyclic nucleotides that activate this kinase in most other organisms?


Assuntos
Leishmania donovani , Trypanosoma brucei brucei , Ligantes , Fosfotransferases/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Nucleosídeos de Purina/metabolismo
16.
Biochem Biophys Res Commun ; 686: 149152, 2023 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-37926042

RESUMO

S-adenosylhomocysteine (SAH) hydrolase is the enzyme responsible for breaking down SAH into adenosine and homocysteine. It has long been believed that a deficiency of this enzyme leads to SAH accumulation, subsequently inhibiting methyltransferases responsible for nucleic acids and proteins, which severely affects cell proliferation. To investigate whether targeting this enzyme could be a viable strategy to combat Trypanosoma brucei, the causative agent of human African trypanosomiasis, we created a null mutant of the SAH hydrolase gene in T. brucei using the Cre/loxP system and conducted a phenotype analysis. Surprisingly, the null mutant, where all five SAH hydrolase gene loci were deleted, exhibited normal proliferation despite the observed SAH accumulation. These findings suggest that inhibiting SAH hydrolase may not be an effective approach to suppressing T. brucei proliferation, making the enzyme a less promising target for antitrypanosome drug development.


Assuntos
Trypanosoma brucei brucei , Humanos , Adenosil-Homocisteinase/genética , Adenosil-Homocisteinase/metabolismo , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/metabolismo , S-Adenosil-Homocisteína/metabolismo , Adenosina/genética , Adenosina/farmacologia
17.
Nat Commun ; 14(1): 7070, 2023 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-37923768

RESUMO

In the skin, Trypanosoma brucei colonises the subcutaneous white adipose tissue, and is proposed to be competent for forward transmission. The interaction between parasites, adipose tissue, and the local immune system is likely to drive the adipose tissue wasting and weight loss observed in cattle and humans infected with T. brucei. However, mechanistically, events leading to subcutaneous white adipose tissue wasting are not fully understood. Here, using several complementary approaches, including mass cytometry by time of flight, bulk and single cell transcriptomics, and in vivo genetic models, we show that T. brucei infection drives local expansion of several IL-17A-producing cells in the murine WAT, including TH17 and Vγ6+ cells. We also show that global IL-17 deficiency, or deletion of the adipocyte IL-17 receptor protect from infection-induced WAT wasting and weight loss. Unexpectedly, we find that abrogation of adipocyte IL-17 signalling results in a significant accumulation of Dpp4+ Pi16+ interstitial preadipocytes and increased extravascular parasites in the WAT, highlighting a critical role for IL-17 signalling in controlling preadipocyte fate, subcutaneous WAT dynamics, and local parasite burden. Taken together, our study highlights the central role of adipocyte IL-17 signalling in controlling WAT responses to infection, suggesting that adipocytes are critical coordinators of tissue dynamics and immune responses to T. brucei infection.


Assuntos
Parasitos , Trypanosoma brucei brucei , Humanos , Camundongos , Animais , Bovinos , Interleucina-17 , Tecido Adiposo , Gordura Subcutânea , Tecido Adiposo Branco , Caquexia
18.
PLoS Pathog ; 19(10): e1011699, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37819951

RESUMO

The long slender bloodstream form Trypanosoma brucei maintains its essential mitochondrial membrane potential (ΔΨm) through the proton-pumping activity of the FoF1-ATP synthase operating in the reverse mode. The ATP that drives this hydrolytic reaction has long been thought to be generated by glycolysis and imported from the cytosol via an ATP/ADP carrier (AAC). Indeed, we demonstrate that AAC is the only carrier that can import ATP into the mitochondrial matrix to power the hydrolytic activity of the FoF1-ATP synthase. However, contrary to expectations, the deletion of AAC has no effect on parasite growth, virulence or levels of ΔΨm. This suggests that ATP is produced by substrate-level phosphorylation pathways in the mitochondrion. Therefore, we knocked out the succinyl-CoA synthetase (SCS) gene, a key mitochondrial enzyme that produces ATP through substrate-level phosphorylation in this parasite. Its absence resulted in changes to the metabolic landscape of the parasite, lowered virulence, and reduced mitochondrial ATP content. Strikingly, these SCS mutant parasites become more dependent on AAC as demonstrated by a 25-fold increase in their sensitivity to the AAC inhibitor, carboxyatractyloside. Since the parasites were able to adapt to the loss of SCS in culture, we also analyzed the more immediate phenotypes that manifest when SCS expression is rapidly suppressed by RNAi. Importantly, when performed under nutrient-limited conditions mimicking various host environments, SCS depletion strongly affected parasite growth and levels of ΔΨm. In totality, the data establish that the long slender bloodstream form mitochondrion is capable of generating ATP via substrate-level phosphorylation pathways.


Assuntos
Trypanosoma brucei brucei , Trypanosoma brucei brucei/metabolismo , Fosforilação , Mitocôndrias/metabolismo , Trifosfato de Adenosina/metabolismo
19.
Artigo em Inglês | MEDLINE | ID: mdl-37757728

RESUMO

Suramin is one of the oldest drugs in use today. It is still the treatment of choice for the hemolymphatic stage of African sleeping sickness caused by Trypanosoma brucei rhodesiense, and it is also used for surra in camels caused by Trypanosoma evansi. Yet despite one hundred years of use, suramin's mode of action is not fully understood. Suramin is a polypharmacological molecule that inhibits diverse proteins. Here we demonstrate that a DNA helicase of the pontin/ruvB-like 1 family, termed T. brucei RuvBL1, is involved in suramin resistance in African trypanosomes. Bloodstream-form T. b. rhodesiense under long-term selection for suramin resistance acquired a homozygous point mutation, isoleucine-312 to valine, close to the ATP binding site of T. brucei RuvBL1. The introduction of this missense mutation, by reverse genetics, into drug-sensitive trypanosomes significantly decreased their sensitivity to suramin. Intriguingly, the corresponding residue of T. evansi RuvBL1 was found mutated in a suramin-resistant field isolate, in that case to a leucine. RuvBL1 (Tb927.4.1270) is predicted to build a heterohexameric complex with RuvBL2 (Tb927.4.2000). RNAi-mediated silencing of gene expression of either T. brucei RuvBL1 or RuvBL2 caused cell death within 72 h. At 36 h after induction of RNAi, bloodstream-form trypanosomes exhibited a cytokinesis defect resulting in the accumulation of cells with two nuclei and two or more kinetoplasts. Taken together, these data indicate that RuvBL1 DNA helicase is involved in suramin action in African trypanosomes.


Assuntos
Trypanosoma brucei brucei , Trypanosoma , Tripanossomíase Africana , Animais , Suramina/farmacologia , Suramina/uso terapêutico , DNA Helicases/genética , Trypanosoma/genética , Tripanossomíase Africana/tratamento farmacológico , Trypanosoma brucei rhodesiense/genética , Trypanosoma brucei brucei/genética
20.
Nat Commun ; 14(1): 5279, 2023 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-37644007

RESUMO

African trypanosomes colonise the skin to ensure parasite transmission. However, how the skin responds to trypanosome infection remains unresolved. Here, we investigate the local immune response of the skin in a murine model of infection using spatial and single cell transcriptomics. We detect expansion of dermal IL-17A-producing Vγ6+ cells during infection, which occurs in the subcutaneous adipose tissue. In silico cell-cell communication analysis suggests that subcutaneous interstitial preadipocytes trigger T cell activation via Cd40 and Tnfsf18 signalling, amongst others. In vivo, we observe that female mice deficient for IL-17A-producing Vγ6+ cells show extensive inflammation and limit subcutaneous adipose tissue wasting, independently of parasite burden. Based on these observations, we propose that subcutaneous adipocytes and Vγ6+ cells act in concert to limit skin inflammation and adipose tissue wasting. These studies provide new insights into the role of γδ T cell and subcutaneous adipocytes as homeostatic regulators of skin immunity during chronic infection.


Assuntos
Dermatite , Trypanosoma brucei brucei , Feminino , Animais , Camundongos , Interleucina-17 , Infecção Persistente , Adiposidade , Obesidade , Caquexia , Inflamação
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