RESUMO
The present work aimed to carry out in vitro biological assays of thiazole compounds against adult worms of Schistosoma mansoni, as well as the in silico determination of pharmacokinetic parameters to predict the oral bioavailability of these compounds. In addition to presenting moderate to low cytotoxicity against mammalian cells, thiazole compounds are not considered hemolytic. All compounds were initially tested at concentrations ranging from 200 to 6.25 µM against adult worms of S. mansoni parasites. The results showed the best activity of PBT2 and PBT5 at a concentration of 200 µM, which caused 100% mortality after 3 h of incubation. While at 6 h of exposure, 100% mortality was observed at the concentration of 100 µM. Subsequent studies with these same compounds allowed classifying PBT5, PBT2, PBT6 and PBT3 compounds, which were considered active and PBT1 and PBT4 compounds, which were considered inactive. In the ultrastructural analysis the compounds PBT2 and PBT5 (200 µM) promoted integumentary changes with exposure of the muscles, formation of integumentary blisters, integuments with abnormal morphology and destruction of tubercles and spicules. Therefore, the compounds PBT2 and PBT5 are promising antiparasitics against S. mansoni.
Assuntos
Esquistossomose mansoni , Esquistossomicidas , Animais , Schistosoma mansoni/ultraestrutura , Tiazóis/farmacologia , Tiazóis/uso terapêutico , Esquistossomicidas/farmacologia , Esquistossomicidas/uso terapêutico , Antiparasitários/uso terapêutico , Esquistossomose mansoni/tratamento farmacológico , MamíferosRESUMO
Treatment and control of schistosomiasis still rely on only one effective drug, praziquantel (PZQ) and, due to mass treatment, the increasing risk of selecting for schistosome strains that are resistant to PZQ has alerted investigators to the urgent need to develop novel therapeutic strategies. The histone-modifying enzymes (HMEs) represent promising targets for the development of epigenetic drugs against Schistosoma mansoni. In the present study, we targeted the S. mansoni lysine-specific demethylase 1 (SmLSD1), a transcriptional corepressor, using a novel and selective synthetic inhibitor, MC3935, which was used to treat schistosomula and adult worms in vitro. By using cell viability assays and optical and electron microscopy, we showed that treatment with MC3935 affected parasite motility, egg-laying, tegument, and cellular organelle structures, culminating in the death of schistosomula and adult worms. In silico molecular modeling and docking analysis suggested that MC3935 binds to the catalytic pocket of SmLSD1. Western blot analysis revealed that MC3935 inhibited SmLSD1 demethylation activity of H3K4me1/2. Knockdown of SmLSD1 by RNAi recapitulated MC3935 phenotypes in adult worms. RNA-Seq analysis of MC3935-treated parasites revealed significant differences in gene expression related to critical biological processes. Collectively, our findings show that SmLSD1 is a promising drug target for the treatment of schistosomiasis and strongly support the further development and in vivo testing of selective schistosome LSD1 inhibitors.
Assuntos
Inibidores Enzimáticos/farmacologia , Histona Desmetilases/antagonistas & inibidores , Schistosoma mansoni/efeitos dos fármacos , Schistosoma mansoni/ultraestrutura , Esquistossomose mansoni/tratamento farmacológico , Animais , Anti-Helmínticos/farmacologia , Resistência a Medicamentos , Microscopia Eletrônica de Varredura , Oviposição/efeitos dos fármacos , Praziquantel/farmacologia , Esquistossomose mansoni/parasitologia , Esquistossomose mansoni/patologiaRESUMO
BACKGROUND: Schistosomiasis chemotherapy is largely based on praziquantel (PZQ). Although PZQ is very safe and tolerable, it does not prevent reinfection and emerging resistance is a primary concern. Recent studies have shown that the targeting of epigenetic machinery in Schistosoma mansoni may result in severe alterations in parasite development, leading to death. This new route for drug discovery in schistosomiasis has focused on classes of histone deacetylases (HDACs) and histone acetyltransferases (HATs) as epigenetic drug targets. Schistosoma histone demethylases also seem to be important in the transition of cercariae into schistosomula, as well as sexual differentiation in adult worms. METHODS: The Target-Pathogen database and molecular docking assays were used to prioritize the druggability of S. mansoni histone demethylases. The transcription profile of Smp_03400 was re-analyzed using available databases. The effect of GSK-J4 inhibitor in schistosomula and adult worms' motility/viability/oviposition was assessed by in vitro assays. Ultrastructural analysis was performed on adult worms exposed to GSK-J4 by scanning electron microscopy, while internal structures and muscle fiber integrity was investigated by confocal microscopy after Langeron's carmine or phalloidin staining. RESULTS: The present evaluation of the potential druggability of 14 annotated S. mansoni demethylase enzymes identified the S. mansoni ortholog of human KDM6A/UTX (Smp_034000) as the most suitable druggable target. In silico analysis and molecular modeling indicated the potential for cofactor displacement by the chemical probe GSK-J4. Our re-analysis of transcriptomic data revealed that Smp_034000 expression peaks at 24 h in newly transformed schistosomula and 5-week-old adult worms. Moreover, this gene was highly expressed in the testes of mature male worms compared to the rest of the parasite body. In in vitro schistosome cultures, treatment with GSK-J4 produced striking effects on schistosomula mortality and adult worm motility and mortality, as well as egg oviposition, in a dose- and time-dependent manner. Unexpectedly, western blot assays did not demonstrate overall modulation of H3K27me3 levels in response to GSK-J4. Confocal and scanning electron microscopy revealed the loss of original features in muscle fibers and alterations in cell-cell contact following GSK-J4 treatment. CONCLUSIONS: GSK-J4 presents promising potential for antischistosomal control; however, the underlying mechanisms warrant further investigation.
Assuntos
Anti-Helmínticos/farmacologia , Benzazepinas/farmacologia , Descoberta de Drogas/métodos , Histona Desmetilases com o Domínio Jumonji/antagonistas & inibidores , Modelos Moleculares , Pirimidinas/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Animais , Biologia Computacional , Epigênese Genética/efeitos dos fármacos , Feminino , Histona Desmetilases com o Domínio Jumonji/genética , Masculino , Microscopia Eletrônica de Varredura , Simulação de Acoplamento Molecular , Schistosoma mansoni/genética , Schistosoma mansoni/ultraestrutura , Esquistossomose mansoni/tratamento farmacológico , TranscriptomaRESUMO
Currently, the control of schistosomiasis is based on a single drug, praziquantel, which is effective against all species of Schistosoma but only in the adult stage, presenting a schistosomicidal deficit at the other developmental stages of the parasites. Recently our research group has demonstrated that the potassium salt of usnic acid (PS-UA) presented schistosomicidal property against couples of adult worms of S. mansoni. Thus, the present study seeks to report for the first time the in vitro activity of PS-UA against different developmental stages of S. mansoni (schistosomules and young worms). As schistosomicide parameters, we evaluated motility, mortality, cell viability of the worms and tegument changes by scanning electron microscopy (SEM). After 3 h exposure, PS-UA was lethal to schistosomules at concentrations of 100 and 50 µM, whereas for concentrations 25 and 12.5 µM, 38 and 18% of mortality and 62 and 24% changes in motility, respectively, were reached. Yet for schistosomules, concentration of 25 µM caused 90 and 100% of death after 6 and 12 h, respectively. In the concentration of 12.5 µM at intervals of 12 and 24 h mortality was 68 and 100%, respectively. For young worms, after 3 h of exposure at concentrations of 200 and 100 µM caused 57 and 27% mortality, respectively. After 12 and 24 h, these concentrations caused mortality of 90 and 100% and 47 and 60% respectively. After 24 h, concentrations of 50 and 25 µM caused 80 and 30% change in motility, respectively. However, at the 12.5 µM concentration no change was observed. In addition, PS-UA reduced the cellular viability of young worms by 50.98% and 85.87% at concentrations of 100 and 200 µM, respectively. In both stages of worms and at different exposure intervals, PS-UA caused alterations such as: dorsoventral contraction, peeling, swelling, blisters, erosion, exposure of subtegumental tissue and disintegration of tegument. According to the results, changes in motility and mortality caused by PS-UA against schistosomules and young worms were concentration and time-dependents, also PS-UA even at low concentration, was able to cause profound ultrastructural changes in the integument of the worms. PS-UA is a promising candidate as prophylactic agent in the control of schistosomiasis mansoni.
Assuntos
Benzofuranos/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Animais , Sobrevivência Celular/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Schistosoma mansoni/crescimento & desenvolvimento , Schistosoma mansoni/ultraestruturaRESUMO
Schistosoma mansoni adult worms are extensively challenged by reactive oxygen species from intrinsic sources. However, the effects of extrinsic sources such as ethanol have not been looked at in schistosomes. We examined adult worms recovered from ethanol-consuming mice by light (LM), confocal (CM) and scanning electron microscopy (SEM) to address this question. Schistosomiasis-infected mice were orally gavaged with 18% (v/v) ethanol from 35 to 63 days post-infection, when they were euthanized. CM examination revealed reduced germ cells density (-36%, pâ¯=â¯0.0001) and sperm density (-58%, pâ¯=â¯0.0001) in testicular lobes, and immature cells in seminal vesicle compared to unexposed control worms. Female worms showed reduced density of vitellin glands (-71%, pâ¯=â¯0.0001), maturation of oocytes (-7%, pâ¯=â¯0.0071) and reduced spermatozoa density (-23%, pâ¯=â¯0.0002) within the seminal receptacle. SEM revealed remarkable damages in male's tegument, including tubercles flattening, tegumental peeling and erosive lesions. Given that lipids are present in reproductive system and tegument, our results suggest that phenotypic changes are due to ethanol-induced lipid peroxidation. To the best of our knowledge, this is the first report revealing the biological action of ethanol intake on adult schistosomes in vivo.
Assuntos
Etanol/administração & dosagem , Schistosoma mansoni/efeitos dos fármacos , Esquistossomose mansoni/parasitologia , Administração Oral , Animais , Etanol/toxicidade , Feminino , Genitália/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Veias Mesentéricas/parasitologia , Camundongos , Microscopia Confocal , Microscopia Eletrônica de Varredura , Estresse Oxidativo/efeitos dos fármacos , Fenótipo , Sistema Porta/parasitologia , Reprodução/efeitos dos fármacos , Schistosoma mansoni/fisiologia , Schistosoma mansoni/ultraestruturaRESUMO
Schistosomiasis is a tropical neglected disease whose socioeconomic impact is surpassed only by malaria. Until recently, praziquantel (PZQ) has been the only available drug, raising concerns that tolerant/resistant strains may appear. Since the discovery of the schistosomicidal potential of artemisinin (ART), new derivatives have been produced and evaluated. In this work, we evaluated the activity of ART derivatives against Schistosoma mansoni, both in vitro and in vivo. In the in vitro assay, worm survival, oviposition, and morphological alterations were evaluated. Further analysis of morphological alterations and membrane integrity was conducted using scanning electron microscopy and a cell-permeable, benzimidazole dye (Hoescht 33258) that binds to the minor groove of double stranded DNA. For the in vivo assay, artesunic acid (AcART) and dihydroartemisinin acetate (AcDQHS) were selected, since they showed the best in vitro results. Infected mice treated 21, 45, or 60 days post-infection (dpi), with a concentration of 100 mg/kg of either AcART or AcDQHS, showed a significant worm reduction (particularly in females), fewer eggs eliminated in feces, and a decrease of immature eggs in the intestinal tissues. Our results indicate that AcART and AcDQHS have some schistosomicidal activity against juvenile and adult stages of S. mansoni.
Assuntos
Artemisininas/farmacologia , Artemisininas/uso terapêutico , Schistosoma mansoni/efeitos dos fármacos , Esquistossomicidas/farmacologia , Esquistossomicidas/uso terapêutico , Animais , Linhagem Celular , Fezes/parasitologia , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Oviposição/efeitos dos fármacos , Schistosoma mansoni/ultraestrutura , Esquistossomose mansoni/tratamento farmacológicoRESUMO
BACKGROUND: The possibility of emergence of praziquantel-resistant Schistosoma parasites and the lack of other effective drugs demand the discovery of new schistosomicidal agents. In this context the study of compounds that target histone-modifying enzymes is extremely promising. Our aim was to investigate the effect of inhibition of EZH2, a histone methyltransferase that is involved in chromatin remodeling processes and gene expression control; we tested different developmental forms of Schistosoma mansoni using GKS343, a selective inhibitor of EZH2 in human cells. METHODOLOGY/PRINCIPAL FINDINGS: Adult male and female worms and schistosomula were treated with different concentrations of GSK343 for up to two days in vitro. Western blotting showed a decrease in the H3K27me3 histone mark in all three developmental forms. Motility, mortality, pairing and egg laying were employed as schistosomicidal parameters for adult worms. Schistosomula viability was evaluated with propidium iodide staining and ATP quantification. Adult worms showed decreased motility when exposed to GSK343. Also, an approximate 40% reduction of egg laying by GSK343-treated females was observed when compared with controls (0.1% DMSO). Scanning electron microscopy showed the formation of bulges and bubbles throughout the dorsal region of GSK343-treated adult worms. In schistosomula the body was extremely contracted with the presence of numerous folds, and growth was markedly slowed. RNA-seq was applied to identify the metabolic pathways affected by GSK343 sublethal doses. GSK343-treated adult worms showed significantly altered expression of genes related to transmembrane transport, cellular homeostasis and egg development. In females, genes related to DNA replication and noncoding RNA metabolism processes were downregulated. Schistosomula showed altered expression of genes related to cell adhesion and membrane synthesis pathways. CONCLUSIONS/SIGNIFICANCE: The results indicated that GSK343 presents in vitro activities against S. mansoni, and the characterization of EZH2 as a new potential molecular target establishes EZH2 inhibitors as part of a promising new group of compounds that could be used for the development of schistosomicidal agents.
Assuntos
Replicação do DNA/efeitos dos fármacos , Proteína Potenciadora do Homólogo 2 de Zeste/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Indazóis/farmacologia , Oviposição/efeitos dos fármacos , Piridonas/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Schistosoma mansoni/fisiologia , Animais , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Locomoção/efeitos dos fármacos , Masculino , Redes e Vias Metabólicas/efeitos dos fármacos , Microscopia Eletrônica de Varredura , RNA não Traduzido/metabolismo , Schistosoma mansoni/enzimologia , Schistosoma mansoni/ultraestrutura , Análise de SobrevidaRESUMO
Phthalimide, 1,3-thiazole, and thiazolidinone cores are considered privileged scaffolds and represent an attractive starting point to design new bioactive compounds for neglected tropical disease (NTD). Schistosomiasis is a NTD, caused by Schistosoma worms which praziquantel (PZQ) is the only drug used to treat humans, but the decrease in the effect after treatment has been reported. Recently, some phthalimide-thiazole derivatives exhibited in vitro antischistosomal activity against adult worms with significant ultrastructural changes and a lower cytotoxic effect on splenocytes. This new biological phthalimido-thiazole profile has motivated us to evaluate a new generation of such molecules in immature and adult worms. Thus, a phthalimido-thiazolidinone derivative, (3c), and three phthalimido-thiazoles (6c, 7a, and 7h) were evaluated concerning their in vitro activity on schistosomulae and adult worms. The results showed that these compounds brought a significant reduction on the mortality, inhibited oviposition, and then induced mortality in immature and adult worms alike. According to scanning electron microscopy, the tegument was the principal target for 7a and 7h and revealed gradual damage to the tegument surface, inducing destruction and decomposition of the tegument in the same areas and exposition of subtegumental tissue and of muscle tissue. Furthermore, they caused less toxicity in splenocytes than PZQ. Compounds 7a and 7h revealed to possess promising activity against larval forms. According to the present study, the privileged structure phthalimido-thiazoles act as a molecular framework that has antischistosomal activity and most form the basis to the next pre-clinical tests. Graphical abstract.
Assuntos
Ftalimidas , Schistosoma mansoni/efeitos dos fármacos , Esquistossomose mansoni/tratamento farmacológico , Tiazóis , Animais , Antiprotozoários/farmacologia , Antiprotozoários/uso terapêutico , Técnicas In Vitro , Microscopia Eletrônica de Varredura , Ftalimidas/química , Ftalimidas/farmacologia , Ftalimidas/uso terapêutico , Schistosoma mansoni/ultraestrutura , Tiazóis/química , Tiazóis/farmacologia , Tiazóis/uso terapêuticoRESUMO
Schistosomiasis is considered a serious public health problem in 78 countries and territories located in Africa, Asia and America and it is estimated in more than 249 million people infected by any of the species of Schistosoma. The exclusive use of praziquantel (PZQ), effective drug against all species of Schistosoma, has been the basis of the development of a possible resistance against the strains of this parasite. In addition, PZQ is not effective against young forms of worms. Thus, there is a need for the development of new drugs with schistosomicidal activity. The objective of this work was to synthesize and to evaluate the therapeutic potential of new benzodioxole derivatives (3-14) candidates for schistosomicidal drugs. All compounds synthesized showed in vitro schistosomicidal activity. The derivative 12 was considered the best compound, since it took 100% of worms to mortality in the first 72â¯h of exposure at the concentration of 100⯵M and 83.3% at the concentration of 50⯵M. Furthermore, male and female adult worms, incubated for 24â¯h with the compound 12 showed tegument damages characterized by extensive desquamation and edema, tuber destruction, bubble formation and exposure of the muscle layer. This compound has a restricted structure, where the thiazolidinone is attached to the 4-position of the 1,3-benzodioxol ring. The structural conformation of derivative 12 was probably responsible for the promising schistosomicidal activity, where the presence of an electron/conformational restriction of the thiazolidine ring, as well as the action of bromine as a bulk substitute, favored an increase in biological activity. In addition, tegumentary changes caused by derivative 12 may also have been responsible for the death of adult worms of Schistosoma mansoni. Therefore, we verified that the results obtained in this study make benzodioxole derivatives possible candidates for prototypes of new schistosomicidal drugs.
Assuntos
Dioxóis/química , Dioxóis/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Esquistossomicidas/síntese química , Esquistossomicidas/farmacologia , Animais , Sobrevivência Celular/efeitos dos fármacos , Dioxóis/uso terapêutico , Células HeLa , Humanos , Microscopia Eletrônica de Varredura , Praziquantel/farmacologia , Praziquantel/uso terapêutico , Schistosoma mansoni/ultraestrutura , Esquistossomose/tratamento farmacológico , Esquistossomose/patologia , Esquistossomicidas/uso terapêuticoRESUMO
Proteasome is a proteolytic complex responsible for intracellular protein turnover in eukaryotes, archaea and in some actinobacteria species. Previous work has demonstrated that in Schistosoma mansoni parasites, the proteasome inhibitor MG-132 affects parasite development. However, the molecular targets affected by MG-132 in S. mansoni are not entirely known. Here, we used expression microarrays to measure the genome-wide changes in gene expression of S. mansoni adult worms exposed in vitro to MG-132, followed by in silico functional analyses of the affected genes using Ingenuity Pathway Analysis (IPA). Scanning electron microscopy was used to document changes in the parasites' tegument. We identified 1,919 genes with a statistically significant (q-value ≤ 0.025) differential expression in parasites treated for 24 h with MG-132, when compared with control. Of these, a total of 1,130 genes were up-regulated and 790 genes were down-regulated. A functional gene interaction network comprised of MG-132 and its target genes, known from the literature to be affected by the compound in humans, was identified here as affected by MG-132. While MG-132 activated the expression of the 26S proteasome genes, it also decreased the expression of 19S chaperones assembly, 20S proteasome maturation, ubiquitin-like NEDD8 and its partner cullin-3 ubiquitin ligase genes. Interestingly, genes that encode proteins related to potassium ion binding, integral membrane component, ATPase and potassium channel activities were significantly down-regulated, whereas genes encoding proteins related to actin binding and microtubule motor activity were significantly up-regulated. MG-132 caused important changes in the worm tegument; peeling, outbreaks and swelling in the tegument tubercles could be observed, which is consistent with interference on the ionic homeostasis in S. mansoni. Finally, we showed the down-regulation of Bax pro-apoptotic gene, as well as up-regulation of two apoptosis inhibitor genes, IAP1 and BRE1, and in contrast, down-regulation of Apaf-1 apoptotic activator, thus suggesting that apoptosis is deregulated in S. mansoni exposed to MG-132. A considerable insight has been gained concerning the potential of MG-132 as a gene expression modulator, and overall the data suggest that the proteasome might be an important molecular target for the design of new drugs against schistosomiasis.