scholarly journals Synthesis of a Sugar-Based Thiosemicarbazone Series and Structure-Activity Relationship versus the Parasite Cysteine Proteases Rhodesain, Cruzain, and Schistosoma mansoni Cathepsin B1

2015 ◽  
Vol 59 (5) ◽  
pp. 2666-2677 ◽  
Author(s):  
Nayara Cristina Fonseca ◽  
Luana Faria da Cruz ◽  
Filipe da Silva Villela ◽  
Glaécia Aparecida do Nascimento Pereira ◽  
Jair Lage de Siqueira-Neto ◽  
...  

ABSTRACTThe pressing need for better drugs against Chagas disease, African sleeping sickness, and schistosomiasis motivates the search for inhibitors of cruzain, rhodesain, andSchistosoma mansoniCB1 (SmCB1), the major cysteine proteases fromTrypanosoma cruzi,Trypanosoma brucei, andS. mansoni, respectively. Thiosemicarbazones and heterocyclic analogues have been shown to be both antitrypanocidal and inhibitory against parasite cysteine proteases. A series of compounds was synthesized and evaluated against cruzain, rhodesain, and SmCB1 through biochemical assays to determine their potency and structure-activity relationships (SAR). This approach led to the discovery of 6 rhodesain, 4 cruzain, and 5 SmCB1 inhibitors with 50% inhibitory concentrations (IC50s) of ≤10 μM. Among the compounds tested, the thiosemicarbazone derivative of peracetylated galactoside (compound 4i) was discovered to be a potent rhodesain inhibitor (IC50= 1.2 ± 1.0 μM). The impact of a range of modifications was determined; removal of thiosemicarbazone or its replacement by semicarbazone resulted in virtually inactive compounds, and modifications in the sugar also diminished potency. Compounds were also evaluatedin vitroagainst the parasitesT. cruzi,T. brucei, andS. mansoni, revealing active compounds among this series.

2011 ◽  
Vol 79 (10) ◽  
pp. 4081-4087 ◽  
Author(s):  
Craig Weinkauf ◽  
Ryan Salvador ◽  
Mercio PereiraPerrin

ABSTRACTTrypanosoma cruzi, the agent of Chagas' disease, infects a variety of mammalian cells in a process that includes multiple cycles of intracellular division and differentiation starting with host receptor recognition by a parasite ligand(s). Earlier work in our laboratory showed that the neurotrophin-3 (NT-3) receptor TrkC is activated byT. cruzisurfacetrans-sialidase, also known as parasite-derived neurotrophic factor (PDNF). However, it has remained unclear whether TrkC is used byT. cruzito enter host cells. Here, we show that a neuronal cell line (PC12-NNR5) relatively resistant toT. cruzibecame highly susceptible to infection when overexpressing human TrkC but not human TrkB. Furthermore,trkCtransfection conferred an ∼3.0-fold intracellular growth advantage. Sialylation-deficient Chinese hamster ovarian (CHO) epithelial cell lines Lec1 and Lec2 also became much more permissive toT. cruziafter transfection with thetrkCgene. Additionally, NT-3 specifically blockedT. cruziinfection of the TrkC-NNR5 transfectants and of naturally permissive TrkC-bearing Schwann cells and astrocytes, as did recombinant PDNF. Two specific inhibitors of Trk autophosphorylation (K252a and AG879) and inhibitors of Trk-induced MAPK/Erk (U0126) and Akt kinase (LY294002) signaling, but not an inhibitor of insulin-like growth factor 1 receptor, abrogated TrkC-mediated cell invasion. Antibody to TrkC blockedT. cruziinfection of the TrkC-NNR5 transfectants and of cells that naturally express TrkC. The TrkC antibody also significantly and specifically reduced cutaneous infection in a mouse model of acute Chagas' disease. TrkC is ubiquitously expressed in the peripheral and central nervous systems, and in nonneural cells infected byT. cruzi, including cardiac and gastrointestinal muscle cells. Thus, TrkC is implicated as a functional PDNF receptor in cell entry, independently of sialic acid recognition, mediating broadT. cruziinfection bothin vitroandin vivo.


2020 ◽  
Vol 64 (9) ◽  
Author(s):  
Julianna Siciliano de Araújo ◽  
Cristiane França da Silva ◽  
Denise da Gama Jaén Batista ◽  
Aline Nefertiti ◽  
Ludmila Ferreira de Almeida Fiuza ◽  
...  

ABSTRACT Pyrazolones are heterocyclic compounds with interesting biological properties. Some derivatives inhibit phosphodiesterases (PDEs) and thereby increase the cellular concentration of cyclic AMP (cAMP), which plays a vital role in the control of metabolism in eukaryotic cells, including the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease (CD), a major neglected tropical disease. In vitro phenotypic screening identified a 4-bromophenyl-dihydropyrazole dimer as an anti-T. cruzi hit and 17 novel pyrazolone analogues with variations on the phenyl ring were investigated in a panel of phenotypic laboratory models. Potent activity against the intracellular forms (Tulahuen and Y strains) was obtained with 50% effective concentration (EC50) values within the 0.17 to 3.3 μM range. Although most were not active against bloodstream trypomastigotes, an altered morphology and loss of infectivity were observed. Pretreatment of the mammalian host cells with pyrazolones did not interfere with infection and proliferation, showing that the drug activity was not the result of changes to host cell metabolism. The pyrazolone NPD-227 increased the intracellular cAMP levels and was able to sterilize T. cruzi-infected cell cultures. Thus, due to its high potency and selectivity in vitro, and its additive interaction with benznidazole (Bz), NPD-227 was next assessed in the acute mouse model. Oral dosing for 5 days of NPD-227 at 10 mg/kg + Bz at 10 mg/kg not only reduced parasitemia (>87%) but also protected against mortality (>83% survival), hence demonstrating superiority to the monotherapy schemes. These data support these pyrazolone molecules as potential novel therapeutic alternatives for Chagas disease.


2015 ◽  
Vol 59 (6) ◽  
pp. 3645-3647 ◽  
Author(s):  
Carolina B. Moraes ◽  
Karen L. White ◽  
Stéphanie Braillard ◽  
Catherine Perez ◽  
Junghyun Goo ◽  
...  

ABSTRACTWith the aim of improving the available drugs for the treatment of Chagas disease, individual enantiomers of nifurtimox were characterized. The results indicate that the enantiomers are equivalent in theirin vitroactivity against a panel ofTrypanosoma cruzistrains;in vivoefficacy in a murine model of Chagas disease;in vitrotoxicity and absorption, distribution, metabolism, and excretion characteristics; andin vivopharmacokinetic properties. There is unlikely to be any therapeutic benefit of an individual nifurtimox enantiomer over the racemic mixture.


2019 ◽  
Vol 63 (6) ◽  
Author(s):  
Ana Lia Mazzeti ◽  
Lívia de F. Diniz ◽  
Karolina R. Gonçalves ◽  
Ruan Schott WonDollinger ◽  
Tassiane Assíria ◽  
...  

ABSTRACT Combination therapy has gained attention as a possible strategy for overcoming the limitations of the present therapeutic arsenal for Chagas disease. The aim of this study was to evaluate the effect of allopurinol in association with nitroheterocyclic compounds on infection with the Y strain of Trypanosoma cruzi. The in vitro effect of allopurinol plus benznidazole or nifurtimox on intracellular amastigotes in infected H9c2 cells was assessed in a 72-h assay. The interactions were classified as synergic for both allopurinol-nifurtimox (sums of fractional inhibitory concentrations [∑FICs] = 0.49 ± 0.08) and allopurinol-benznidazole (∑FICs = 0.48 ± 0.09). In the next step, infected Swiss mice were treated with allopurinol at 30, 60, and 90 mg/kg of body weight and with benznidazole at 25, 50, and 75 mg/kg in monotherapy and in combination at the same doses; as a reference treatment, another group of animals received benznidazole at 100 mg/kg. Allopurinol in monotherapy led to a smaller or nil effect in the reduction of parasite load and mortality rate. Treatment with benznidazole at suboptimal doses induced a transient suppression of parasitaemia with subsequent relapse in all animals treated with 25 and 50 mg/kg and in 80% of those that received 75 mg/kg. Administration of the drugs in combination significantly increased the cure rate to 60 to 100% among mice treated with benznidazole at 75 mg/kg plus 30, 60, or 90 mg/kg of allopurinol. These results show a positive interaction between allopurinol and benznidazole, and since both drugs are commercially available, their use in combination may be considered for the assessment in the treatment of Chagas disease patients.


2019 ◽  
Vol 64 (2) ◽  
Author(s):  
Roberto I. Cuevas-Hernández ◽  
Richard M. B. M. Girard ◽  
Sarai Martínez-Cerón ◽  
Marcelo Santos da Silva ◽  
Maria Carolina Elias ◽  
...  

ABSTRACT Chagas disease (CD) is a human infection caused by Trypanosoma cruzi. CD was traditionally endemic to the Americas; however, due to migration it has spread to countries where it is not endemic. The current chemotherapy to treat CD induces several side effects, and its effectiveness in the chronic phase of the disease is controversial. In this contribution, substituted phenylbenzothiazole derivatives were synthesized and biologically evaluated as trypanocidal agents against Trypanosoma cruzi. The trypanocidal activities of the most promising compounds were determined through systematic in vitro screening, and their modes of action were determined as well. The physicochemical-structural characteristics responsible for the trypanocidal effects were identified, and their possible therapeutic application in Chagas disease is discussed. Our results show that the fluorinated compound 2-methoxy-4-[5-(trifluoromethyl)-1,3-benzothiazol-2-yl] phenol (BT10) has the ability to inhibit the proliferation of epimastigotes [IC50(Epi) = 23.1 ± 1.75 μM] and intracellular forms of trypomastigotes [IC50(Tryp) = 8.5 ± 2.9 μM] and diminishes the infection index by more than 80%. In addition, BT10 has the ability to selectively fragment 68% of the kinetoplastid DNA compared with 5% of nucleus DNA. The mode of action for BT10 on T. cruzi suggests that the development of fluorinated phenylbenzothiazole with electron-withdrawing substituent is a promising strategy for the design of trypanocidal drugs.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Rômulo D. Novaes ◽  
Eliziária C. Santos ◽  
Marli C. Cupertino ◽  
Daniel S. S. Bastos ◽  
Andréa A. S. Mendonça ◽  
...  

Suramin (Sur) acts as an ecto-NTPDase inhibitor in Trypanosoma cruzi and a P2-purinoceptor antagonist in mammalian cells. Although the potent antitrypanosomal effect of Sur has been shown in vitro, limited evidence in vivo suggests that this drug can be dangerous to T. cruzi-infected hosts. Therefore, we investigated the dose-dependent effect of Sur-based chemotherapy in a murine model of Chagas disease. Seventy uninfected and T. cruzi-infected male C57BL/6 mice were randomized into five groups: SAL = uninfected; INF = infected; SR5, SR10, and SR20 = infected treated with 5, 10, or 20 mg/kg Sur. In addition to its effect on blood and heart parasitism, the impact of Sur-based chemotherapy on leucocytes myocardial infiltration, cytokine levels, antioxidant defenses, reactive tissue damage, and mortality was analyzed. Our results indicated that animals treated with 10 and 20 mg/kg Sur were disproportionally susceptible to T. cruzi, exhibiting increased parasitemia and cardiac parasitism (amastigote nests and parasite load (T. cruzi DNA)), intense protein, lipid and DNA oxidation, marked myocarditis, and mortality. Animals treated with Sur also exhibited reduced levels of nonprotein antioxidants. However, the upregulation of catalase, superoxide dismutase, and glutathione-S-transferase was insufficient to counteract reactive tissue damage and pathological myocardial remodeling. It is still poorly understood whether Sur exerts a negative impact on the purinergic signaling of T. cruzi-infected host cells. However, our findings clearly demonstrated that through enhanced parasitism, inflammation, and reactive tissue damage, Sur-based chemotherapy contributes to aggravating myocarditis and increasing mortality rates in T. cruzi-infected mice, contradicting the supposed relevance attributed to this drug for the treatment of Chagas disease.


2015 ◽  
Vol 59 (10) ◽  
pp. 5999-6006 ◽  
Author(s):  
Eliziária C. Santos ◽  
Rômulo D. Novaes ◽  
Marli C. Cupertino ◽  
Daniel S. S. Bastos ◽  
Raphael C. Klein ◽  
...  

ABSTRACTAlthough suramin (Sur) is suggested as a potential drug candidate in the management of Chagas disease, this issue has not been objectively tested. In this study, we examined the applicability of concomitant treatment with benznidazole (Bz) and suramin in mice infected with a virulent strain ofTrypanosoma cruzi. Eighty 12-week-old male C57BL/6 mice were equally randomized in eight groups: (i) noninfected mice (negative control) and mice infected withT. cruziY strain receiving (ii) no treatment (positive control), (iii) Bz, 100 mg/kg of body weight per day, (iv) Sur, 20 mg/kg/day, and (v to viii) Sur, 20 mg/kg/day, combined with Bz, 100, 50, 25, or 5 mg/kg/day. Bz was administered by gavage, and Sur was administered intraperitoneally. Sur dramatically increased the parasitemia, cardiac content of parasite DNA, inflammation, oxidative tissue damage, and mortality. In response to high parasitic load in cardiac tissue, Sur stimulated the immune system in a manner typical of the acute phase of Chagas disease, increasing tissue levels of gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α) and inducing a preferential IgG2a anti-T. cruziserum pattern. When Sur and Bz were combined, the infection severity was attenuated, showing a dose-dependent Bz response. Sur therapy had a more harmful effect on the host than on the parasite and reduced the efficacy of Bz againstT. cruziinfection. Considering that Sur drastically reinforced the infection evolution, potentiating the inflammatory process and the severity of cardiac lesions, thein vivofindings contradicted thein vitroanti-T. cruzipotential described for this drug.


2016 ◽  
Vol 60 (4) ◽  
pp. 2425-2434 ◽  
Author(s):  
F. H. Guedes-da-Silva ◽  
D. G. J. Batista ◽  
M. B. Meuser ◽  
K. C. Demarque ◽  
T. O. Fulco ◽  
...  

ABSTRACTArylimidamides (AIAs) have been shown to have considerable biological activity against intracellular pathogens, includingTrypanosoma cruzi, which causes Chagas disease. In the present study, the activities of 12 novel bis-AIAs and 2 mono-AIAs against different strains ofT. cruziin vitroandin vivowere analyzed. The most active wasm-terphenyl bis-AIA (35DAP073), which had a 50% effective concentration (EC50) of 0.5 μM for trypomastigotes (Y strain), which made it 26-fold more effective than benznidazole (Bz; 13 μM). It was also active against the Colombiana strain (EC50= 3.8 μM). Analysis of the activity against intracellular forms of the Tulahuen strain showed that this bis-AIA (EC50= 0.04 μM) was about 100-fold more active than Bz (2 μM). The trypanocidal effect was dissociated from the ability to trigger intracellular lipid bodies within host cells, detected by oil red labeling. Both an active compound (35DAP073) and an inactive compound (26SMB060) displayed similar activation profiles. Due to their high selectivity indexes, two AIAs (35DAP073 and 35DAP081) were moved toin vivostudies, but because of the results of acute toxicity assays, 35DAP081 was excluded from the subsequent tests. The findings obtained with 35DAP073 treatment of infections caused by the Y strain revealed that 2 days of therapy induced a dose-dependent action, leading to 96 to 46% reductions in the level of parasitemia. However, the administration of 10 daily doses in animals infected with the Colombiana strain resulted in toxicity, preventing longer periods of treatment. The activity of the combination of 0.5 mg/kg of body weight/day 35DAP073 with 100 mg/kg/day Bz for 10 consecutive days was then assayed. Treatment with the combination resulted in the suppression of parasitemia, the elimination of neurological toxic effects, and survival of 100% of the animals. Quantitative PCR showed a considerable reduction in the parasite load (60%) compared to that achieved with Bz or the amidine alone. Our results support further investigations of this class with the aim of developing novel alternatives for the treatment of Chagas disease.


2019 ◽  
Vol 202 (8) ◽  
Author(s):  
Courtney E. Price ◽  
Dustin G. Brown ◽  
Dominique H. Limoli ◽  
Vanessa V. Phelan ◽  
George A. O’Toole

ABSTRACT Cystic fibrosis (CF) patients chronically infected with both Pseudomonas aeruginosa and Staphylococcus aureus have worse health outcomes than patients who are monoinfected with either P. aeruginosa or S. aureus. We showed previously that mucoid strains of P. aeruginosa can coexist with S. aureus in vitro due to the transcriptional downregulation of several toxic exoproducts typically produced by P. aeruginosa, including siderophores, rhamnolipids, and HQNO (2-heptyl-4-hydroxyquinoline N-oxide). Here, we demonstrate that exogenous alginate protects S. aureus from P. aeruginosa in both planktonic and biofilm coculture models under a variety of nutritional conditions. S. aureus protection in the presence of exogenous alginate is due to the transcriptional downregulation of pvdA, a gene required for the production of the iron-scavenging siderophore pyoverdine as well as the downregulation of the PQS (Pseudomonas quinolone signal) (2-heptyl-3,4-dihydroxyquinoline) quorum sensing system. The impact of exogenous alginate is independent of endogenous alginate production. We further demonstrate that coculture of mucoid P. aeruginosa with nonmucoid P. aeruginosa strains can mitigate the killing of S. aureus by the nonmucoid strain of P. aeruginosa, indicating that the mechanism that we describe here may function in vivo in the context of mixed infections. Finally, we investigated a panel of mucoid clinical isolates that retain the ability to kill S. aureus at late time points and show that each strain has a unique expression profile, indicating that mucoid isolates can overcome the S. aureus-protective effects of mucoidy in a strain-specific manner. IMPORTANCE CF patients are chronically infected by polymicrobial communities. The two dominant bacterial pathogens that infect the lungs of CF patients are P. aeruginosa and S. aureus, with ∼30% of patients coinfected by both species. Such coinfected individuals have worse outcomes than monoinfected patients, and both species persist within the same physical space. A variety of host and environmental factors have been demonstrated to promote P. aeruginosa-S. aureus coexistence, despite evidence that P. aeruginosa kills S. aureus when these organisms are cocultured in vitro. Thus, a better understanding of P. aeruginosa-S. aureus interactions, particularly mechanisms by which these microorganisms are able to coexist in proximal physical space, will lead to better-informed treatments for chronic polymicrobial infections.


2020 ◽  
Vol 7 ◽  
Author(s):  
Katarzyna I. Jankowska ◽  
Rana Nagarkatti ◽  
Nirmallya Acharyya ◽  
Neetu Dahiya ◽  
Caitlin F. Stewart ◽  
...  

The introduction of pathogen reduction technologies (PRTs) to inactivate bacteria, viruses and parasites in donated blood components stored for transfusion adds to the existing arsenal toward reducing the risk of transfusion-transmitted infectious diseases (TTIDs). We have previously demonstrated that 405 nm violet-blue light effectively reduces blood-borne bacteria in stored human plasma and platelet concentrates. In this report, we investigated the microbicidal effect of 405 nm light on one important bloodborne parasite Trypanosoma cruzi that causes Chagas disease in humans. Our results demonstrated that a light irradiance at 15 mWcm−2 for 5 h, equivalent to 270 Jcm−2, effectively inactivated T. cruzi by over 9.0 Log10, in plasma and platelets that were evaluated by a MK2 cell infectivity assay. Giemsa stained T. cruzi infected MK2 cells showed that the light-treated parasites in plasma and platelets were deficient in infecting MK2 cells and did not differentiate further into intracellular amastigotes unlike the untreated parasites. The light-treated and untreated parasite samples were then evaluated for any residual infectivity by injecting the treated parasites into Swiss Webster mice, which did not develop infection even after the animals were immunosuppressed, further demonstrating that the light treatment was completely effective for inactivation of the parasite; the light-treated platelets had similar in vitro metabolic and biochemical indices to that of untreated platelets. Overall, these results provide a proof of concept toward developing 405 nm light treatment as a pathogen reduction technology (PRT) to enhance the safety of stored human plasma and platelet concentrates from bloodborne T. cruzi, which causes Chagas disease.


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