Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Mais filtros

Base de dados
Tipo de documento
Assunto da revista
País de afiliação
Intervalo de ano de publicação
1.
ACS Chem Biol ; 17(6): 1415-1426, 2022 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-35649238

RESUMO

Epigenetics has received much attention in the past decade. Many insights on epigenetic (dys)regulation in diseases have been obtained, and clinical therapies targeting them are in place. However, the readers of the epigenetic marks are lacking enlightenment behind this revolution, and it is poorly understood how DNA methylation is being read and translated to chromatin function and cellular responses. Chemical probes targeting the methyl-CpG readers, such as the methyl-CpG binding domain proteins (MBDs), could be used to study this mechanism. We have designed analogues of 5-methylcytosine to probe the MBD domain of human MBD2. By setting up a protein thermal shift assay and an AlphaScreen-based test, we were able to identify three fragments that bind MBD2 alone and disrupt the MBD2-methylated DNA interactions. Two-dimensional NMR experiments and virtual docking gave valuable insights into the interaction of the ligands with the protein showing that the compounds interact with residues that are important for DNA recognition. These constitute the starting point for the design of potent chemical probes for MBD proteins.


Assuntos
Metilação de DNA , Proteínas de Ligação a DNA , 5-Metilcitosina/metabolismo , Ilhas de CpG , DNA/química , Proteínas de Ligação a DNA/metabolismo , Humanos
2.
mBio ; 12(6): e0255821, 2021 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-34724812

RESUMO

Malaria parasites need to cope with changing environmental conditions that require strong countermeasures to ensure pathogen survival in the human and mosquito hosts. The molecular mechanisms that protect Plasmodium falciparum homeostasis during the complex life cycle remain unknown. Here, we identify cytosine methylation of tRNAAsp (GTC) as being critical to maintain stable protein synthesis. Using conditional knockout (KO) of a member of the DNA methyltransferase family, called Pf-DNMT2, RNA bisulfite sequencing demonstrated the selective cytosine methylation of this enzyme of tRNAAsp (GTC) at position C38. Although no growth defect on parasite proliferation was observed, Pf-DNMT2KO parasites showed a selective downregulation of proteins with a GAC codon bias. This resulted in a significant shift in parasite metabolism, priming KO parasites for being more sensitive to various types of stress. Importantly, nutritional stress made tRNAAsp (GTC) sensitive to cleavage by an unknown nuclease and increased gametocyte production (>6-fold). Our study uncovers an epitranscriptomic mechanism that safeguards protein translation and homeostasis of sexual commitment in malaria parasites. IMPORTANCE P. falciparum is the most virulent malaria parasite species, accounting for the majority of the disease mortality and morbidity. Understanding how this pathogen is able to adapt to different cellular and environmental stressors during its complex life cycle is crucial in order to develop new strategies to tackle the disease. In this study, we identified the writer of a specific tRNA cytosine methylation site as a new layer of epitranscriptomic regulation in malaria parasites that regulates the translation of a subset of parasite proteins (>400) involved in different metabolic pathways. Our findings give insight into a novel molecular mechanism that regulates P. falciparum response to drug treatment and sexual commitment.


Assuntos
Citosina/metabolismo , Metiltransferases/metabolismo , Plasmodium falciparum/genética , Proteínas de Protozoários/metabolismo , RNA de Protozoário/genética , RNA de Transferência/genética , Metilação de DNA , Epigenoma , Humanos , Malária Falciparum/parasitologia , Metiltransferases/genética , Plasmodium falciparum/enzimologia , Plasmodium falciparum/fisiologia , Proteínas de Protozoários/genética , Processamento Pós-Transcricional do RNA , RNA de Protozoário/metabolismo , RNA de Transferência/metabolismo , Estresse Fisiológico
3.
J Med Chem ; 64(14): 10403-10417, 2021 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-34185525

RESUMO

Epigenetic post-translational modifications are essential for human malaria parasite survival and progression through its life cycle. Here, we present new functionalized suberoylanilide hydroxamic acid (SAHA) derivatives that chemically combine the pan-histone deacetylase inhibitor SAHA with the DNA methyltransferase inhibitor procainamide. A three- or four-step chemical synthesis was designed starting from cheap raw materials. Compared to the single drugs, the combined molecules showed a superior activity in Plasmodium and a potent inhibition against human HDAC6, exerting no cytotoxicity in human cell lines. These new compounds are fully active in multidrug-resistant Plasmodium falciparum Cambodian isolates. They target transmission of the parasite by inducing irreversible morphological changes in gametocytes and inhibiting exflagellation. The compounds are slow-acting and have an additive antimalarial effect in combination with fast-acting epidrugs and dihydroartemisinin. The lead compound decreases parasitemia in mice in a severe malaria model. Taken together, this novel fused molecule offers an affordable alternative to current failing antimalarial therapy.


Assuntos
Antimaláricos/farmacologia , Desacetilase 6 de Histona/antagonistas & inibidores , Inibidores de Histona Desacetilases/farmacologia , Ácidos Hidroxâmicos/farmacologia , Malária Falciparum/tratamento farmacológico , Plasmodium falciparum/efeitos dos fármacos , Procainamida/farmacologia , Antimaláricos/síntese química , Antimaláricos/química , Relação Dose-Resposta a Droga , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Desacetilase 6 de Histona/metabolismo , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/química , Ácidos Hidroxâmicos/química , Estrutura Molecular , Procainamida/química , Relação Estrutura-Atividade
4.
ACS Cent Sci ; 6(1): 16-21, 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31989022

RESUMO

Malaria is the deadliest parasitic disease affecting over 200 million people worldwide. The increasing number of treatment failures due to multi-drug-resistant parasites in South-East Asia hinders the efforts for elimination. It is thus urgent to develop new antimalarials to contain these resistant parasites. Based on a previous report showing the presence of DNA methylation in Plasmodium, we generated new types of DNA methylation inhibitors against malaria parasites. The quinoline-quinazoline-based inhibitors kill parasites, including artemisinin-resistant field isolates adapted to culture, in the low nanomolar range. The compounds target all stages of the asexual cycle, including early rings, during a 6 h treatment period; they reduce DNA methylation in the parasite and show in vivo activity at 10 mg/kg. These potent inhibitors are a new starting point to develop fast-acting antimalarials that could be used in combination with artemisinins.

5.
AMB Express ; 9(1): 175, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31673806

RESUMO

Flavin-dependent halogenases (FHals) catalyse the halogenation of electron-rich substrates, mainly aromatics. Halogenated compounds have many applications, as pharmaceutical, agrochemicals or as starting materials for the synthesis of complex molecules. By exploring the sequenced bacterial diversity, we discovered and characterized XszenFHal, a novel FHal from Xenorhabdus szentirmaii, a symbiotic bacterium of entomopathogenic nematode. The substrate scope of XszenFHal was examined and revealed activities towards tryptophan, indole and indole derivatives, leading to the formation of the corresponding 5-chloro products. XszenFHal makes a valuable addition to the panel of flavin-dependent halogenases already discovered and enriches the potential for biotechnology applications by allowing access to 5-halogenated indole derivatives.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA