Mitochondria as a potential target for the development of prophylactic and therapeutic drugs against Schistosoma mansoni infection

Author(s):  
Keith Kiplangat Talaam ◽  
Daniel Ken Inaoka ◽  
Takeshi Hatta ◽  
Daigo Tsubokawa ◽  
Naotoshi Tsuji ◽  
...  

Emergence of parasites resistant to praziquantel, the only therapeutic agent, and its ineffectiveness as a prophylactic agent (inactive against the migratory/juvenile Schistosoma mansoni ), makes the development of new antischistosomal drugs urgent. The parasite’s mitochondrion is an attractive target for drug development because this organelle is essential for survival throughout the parasite’s life cycle. We investigated the effects of 116 compounds against Schistosoma mansoni cercariae motility that have been reported to affect mitochondria-related processes in other organisms. Next, eight compounds plus two controls (mefloquine and praziquantel) were selected and assayed against motility of schistosomula ( in vitro ) and adults ( ex vivo ). Prophylactic and therapeutic assays were performed using infected mouse models. Inhibition of oxygen consumption rate (OCR) was assayed using Seahorse XFe24 Analyzer. All selected compounds showed excellent prophylactic activity, reducing the worm burden in the lungs to less than 15% that obtained in the vehicle control. Notably, ascofuranone showed the highest activity with a 98% reduction of the worm burden, suggesting the potential for development of ascofuranone as a prophylactic agent. The worm burden of infected mice with S. mansoni at the adult stage was reduced by more than 50% in mice treated with mefloquine, nitazoxanide, amiodarone, ascofuranone, pyrvinium pamoate, or plumbagin. Moreover, adult mitochondrial OCR was severely inhibited by ascofuranone, atovaquone, and nitazoxanide, while pyrvinium pamoate inhibited both mitochondrial and non-mitochondrial OCRs. These results demonstrate that the mitochondria of S. mansoni are feasible target for drug development.

2020 ◽  
Vol 64 (11) ◽  
Author(s):  
Mariana G. de Brito ◽  
Ana C. Mengarda ◽  
George L. Oliveira ◽  
Maria E. Cirino ◽  
Tais C. Silva ◽  
...  

ABSTRACT Praziquantel is currently the only drug available to treat schistosomiasis, a disease of enormous public health significance caused by a blood fluke of the genus Schistosoma. Diminazene, a drug approved by the FDA, has been successfully used to treat diseases caused by blood protozoan parasites. In this study, we evaluated the antiparasitic properties of diminazene against Schistosoma mansoni ex vivo and in mice harboring either chronic or early S. mansoni infections. In vitro, we monitored phenotypic and tegumental changes as well as the effects of the drug on pairing and egg production. In mice infected with either adult (chronic infection) or immature (early infection) worms, diminazene was administered intraperitoneally (10 to 100 mg/kg of body weight) or by oral gavage (100 to 400 mg/kg), and we studied the influence of the drug on worm burden and egg production. Liver and spleen pathologies and serum aminotransferase levels were also analyzed. In vitro, 50% effective concentrations (EC50) and EC90 revealed that diminazene is able to kill both immature and adult parasites, and its effect was time and concentration dependent. In addition, confocal laser scanning microscopy showed morphological alterations in the teguments of schistosomes. In an animal model, the influence of the drug on worm burden, egg production, hepatomegaly, and splenomegaly depended on the dosing regimen applied and the route of administration. Diminazene also caused a significant reduction in aminotransferase levels. Comparatively, diminazene treatment was more effective in chronic infection than in early infection. In tandem, our study revealed that diminazene possesses anthelmintic properties and inhibits liver injury caused by Schistosoma eggs.


2014 ◽  
Vol 58 (9) ◽  
pp. 5466-5472 ◽  
Author(s):  
Isabel Meister ◽  
Katrin Ingram-Sieber ◽  
Noemi Cowan ◽  
Matthew Todd ◽  
Murray N. Robertson ◽  
...  

ABSTRACTA racemic mixture ofRandSenantiomers of praziquantel (PZQ) is currently the treatment of choice for schistosomiasis. Though theSenantiomer and the metabolites are presumed to contribute only a little to the activity of the drug, in-depth side-by-side studies are lacking. The aim of this study was to investigate thein vitroactivities of PZQ and its main metabolites, namely,R- andS-cis- andR- andS-trans-4′-hydroxypraziquantel, against adult worms and newly transformed schistosomula (NTS). Additionally, we explored thein vivoactivity and hepatic shift (i.e., the migration of the worms to the liver) produced by each PZQ enantiomer in mice. Fifty percent inhibitory concentrations ofR-PZQ,S-PZQ, andR-trans- andR-cis-4′-hydroxypraziquantel of 0.02, 5.85, 4.08, and 2.42 μg/ml, respectively, for adultS. mansoniwere determinedin vitro. S-trans- andS-cis-4′-hydroxypraziquantel were not active at 100 μg/ml. These results are consistent with microcalorimetry data and studies with NTS.In vivo, single 400-mg/kg oral doses ofR-PZQ andS-PZQ achieved worm burden reductions of 100 and 19%, respectively. Moreover, worms treatedin vivowithS-PZQ displayed an only transient hepatic shift and returned to the mesenteric veins within 24 h. Our data confirm thatR-PZQ is the main effector molecule, whileS-PZQ and the metabolites do not play a significant role in the antischistosomal properties of PZQ.


2019 ◽  
Vol 63 (12) ◽  
Author(s):  
Daniel B. Roquini ◽  
Ramon M. Cogo ◽  
Ana C. Mengarda ◽  
Susana F. Mazloum ◽  
Cristiane S. Morais ◽  
...  

ABSTRACT The treatment and control of schistosomiasis, a neglected disease that affects more than 200 million people worldwide, rely on the use of a single drug, praziquantel. A vaccine has yet to be developed, and since new drug design and development is a lengthy and costly process, drug repurposing is a promising strategy. In this study, the efficacy of promethazine, a first-generation antihistamine, was evaluated against Schistosoma mansoni ex vivo and in a murine model of schistosomiasis. In vitro assays demonstrated that promethazine affected parasite motility and viability, and it induced severe tegumental damage in schistosomes. The 50% lethal concentration (LC50) of the drug was 5.84 μM. Similar to promethazine, schistosomes incubated with atropine, a classical anticholinergic drug, displayed reduced motor activity. In an animal model, promethazine treatment was introduced at an oral dose of 100 mg/kg of body weight for five successive days at different intervals from the time of infection for the evaluation of the stage-specific susceptibility (prepatent and patent infections). Various parasitological criteria indicated the following in vivo antischistosomal effects of promethazine: there were significant reductions in worm burden, egg production, hepatomegaly, and splenomegaly. The highest worm burden reduction was achieved with promethazine in patent infections (>90%). Taken together, considering the importance of the repositioning of drugs in infectious diseases, especially those related to poverty, our data revealed the possibility of promethazine repositioning as an antischistosomal agent.


Microbiology ◽  
2011 ◽  
Vol 157 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Vinayak Singh ◽  
Deepak Chandra ◽  
Brahm S. Srivastava ◽  
Ranjana Srivastava

Acetohydroxyacid synthase (AHAS) is a biosynthetic enzyme essential for de novo synthesis of branched-chain amino acids. The genome sequence of Mycobacterium tuberculosis revealed genes encoding four catalytic subunits, ilvB1 (Rv3003c), ilvB2 (Rv3470c), ilvG (Rv1820) and ilvX (Rv3509c), and one regulatory subunit, ilvN (Rv3002c), of AHAS. All these genes were found to be expressed in M. tuberculosis growing in vitro. Each AHAS subunit gene was cloned and expressed in Escherichia coli. AHAS activity of IlvB1 and IlvG was found in cell-free lysates and with recombinant purified proteins. Kinetic studies with purified IlvG revealed positive cooperativity towards substrate and cofactors. To understand the role of the catalytic subunits in the biology of M. tuberculosis, expression of AHAS genes was analysed in different physiological conditions. ilvB1, ilvB2 and ilvG were differentially expressed. The role of ilvB1 in persistence is known, but the upregulation of ilvB2 and ilvG in extended stationary phase, ex vivo, and in acid stress and hypoxic environments, suggests the relevance of AHAS enzymes in the metabolism and survival of M. tuberculosis by functioning as catabolic AHAS. These enzymes are therefore potential targets for drug development.


2015 ◽  
Vol 59 (4) ◽  
pp. 1935-1941 ◽  
Author(s):  
Noemi Cowan ◽  
Philipp Dätwyler ◽  
Beat Ernst ◽  
Chunkai Wang ◽  
Jonathan L. Vennerstrom ◽  
...  

ABSTRACTThere is an unmet need to discover and develop novel antischistosomal drugs. As exemplified by MMV665852,N,N′-diarylureas have recently emerged as a promising antischistosomal chemotype. In this study, we evaluated the structure-activity relationships of 46 commercially available analogs of MMV665852 on newly transformed schistosomula (NTS) and adultSchistosoma mansoniwormsin vitro. Active compounds were evaluated with a cytotoxicity assay,in silicocalculations, metabolic stability studies, and anin vivoassay with mice harboring adultS. mansoniworms. Of the 46 compounds tested at 33.3 μM, 13 and 14 compounds killed NTS and adult worms, respectively, within 72 h. Nine compounds had 90% inhibitory concentrations (IC90s) of ≤10 μM against adult worms, with selectivity indexes of ≥2.8. Their physicochemical properties and permeation through an artificial membrane indicated good to moderate intestinal absorption. Their metabolic stabilities ranged from low to high. Despite satisfactoryin vitroresults andin silicopredictions, only one compound resulted in a statistically significant worm burden reduction (66%) after administration of a single oral dose of 400 mg/kg of body weight toS. mansoni-infected mice. Worm burden reductions of 0 to 43% were observed for the remaining eight compounds tested. In conclusion, several analogs of theN,N′-diarylurea MMV665852 had high efficacy againstS. mansoniin vitroand favorable physicochemical properties for permeation through the intestinal wall. To counteract the low efficacy observed in the mouse model, further investigations should focus on identifying compounds with improved solubility and pharmacokinetic properties.


2020 ◽  
Vol 22 (3) ◽  
Author(s):  
Johanna Eriksson ◽  
Erik Sjögren ◽  
Hans Lennernäs ◽  
Helena Thörn

AbstractThe ex vivo isolated perfused rat lung (IPL) model has been demonstrated to be a useful tool during drug development for studying pulmonary drug absorption. This study aims to investigate the potential use of IPL data to predict rat in vivo lung absorption. Absorption parameters determined from IPL data (ex vivo input parameters) in combination with intravenously determined pharmacokinetic data were used in a biopharmaceutics model to predict experimental rat in vivo plasma concentration-time profiles and lung amount after inhalation of five different inhalation compounds. The performance of simulations using ex vivo input parameters was compared with simulations using in vitro input parameters, to determine whether and to what extent predictability could be improved by using input parameters determined from the more complex ex vivo model. Simulations using ex vivo input parameters were within twofold average difference (AAFE < 2) from experimental in vivo data for all compounds except one. Furthermore, simulations using ex vivo input parameters performed significantly better than simulations using in vitro input parameters in predicting in vivo lung absorption. It could therefore be advantageous to base predictions of drug performance on IPL data rather than on in vitro data during drug development to increase mechanistic understanding of pulmonary drug absorption and to better understand how different substance properties and formulations might affect in vivo behavior of inhalation compounds.


2005 ◽  
Vol 65 (4) ◽  
pp. 729-733 ◽  
Author(s):  
M. M. Vilar ◽  
R. M. Pinto

The present investigation involves a reevaluation of previous results obtained after experimental infection of Swiss Webster mice with cercariae and schistosomula of the Schistosoma mansoni LE strain maintained under laboratory conditions. Three experimental groups of mice were considered: the animals of the first group were percutaneously (ring method) infected with cercariae, those of the second were subcutaneously inoculated with cercariae and the mice of the third were inoculated by the same route with schistosomula transformed in vitro. The data obtained so far indicated that the most effective method of infection is the subcutaneous injection with schistosomula, with a mean adult worm burden recovery of 54.1% when compared to the abdominal percutaneous and subcutaneous routes of infection with cercariae, in which the values were 36.7% and 32.4%, respectively. This suggests that, in experimental infections of SW mice with a LE S. mansoni strain, the skin is to be considered an effective attrition site in the percutaneous route, whereas in the case of inoculation with cercariae, a small amount of larvae fails to be transformed into viable schistosomula, possibly due to skin phase avoidance. A brief discussion about attrition sites and elimination of larval S. mansoni worms in mice is presented.


2020 ◽  
Vol 8 (1) ◽  
pp. 44-49
Author(s):  
Ievgeniia Kocherova ◽  
Bartosz Kempisty ◽  
Greg Hutchings ◽  
Lisa Moncrieff ◽  
Claudia Dompe ◽  
...  

AbstractIn vitro models represent an alternative technique to in vivo or ex vivo studies in the drug development process. Cell-based assays are used to measure the level of proliferation and toxicity, as well as activation of signalling pathways and changes in morphology in cultivated cells. The studies conducted in vitro are aimed to estimate the newly synthesised drugs’ ability to permeate biological barriers and exert their therapeutic or cytotoxic effects. However, more than half of all studied drugs fail in the second or third phase of clinical trials due to a lack of confirmed efficacy. About a third of drugs fail because of safety issues, such as unacceptable levels of toxicity. To reduce attrition level in drug development, it is crucial to consider the implementation of translational phenotypic assays as well as to decipher various molecular mechanisms of action for new molecular entities. In this review, we summarise the existing cell-based methods most frequently used in the studies on drugs, taking into account their advantages and drawbacks.Running title: Cell-based approaches in drug development


2019 ◽  
Vol 94 ◽  
Author(s):  
R.M. Sarhan ◽  
H.S. Thabet ◽  
J.T. Nazeer ◽  
S. William

Abstract Schistosomiasis affects millions globally. There is no vaccine, and treatment depends entirely on praziquantel (PZQ). Field isolates exhibit reduced susceptibility to PZQ, and resistance has been experimentally induced, suggesting that reliance on a single treatment is particularly dangerous. The present study investigated the value of cinnarizine and griseofulvin against Schistosoma mansoni through their in vitro effects on adult worms and oviposition as well as in vivo evaluation in early and late infection, compared to PZQ, in a preliminary experimental model. In vitro, both cinnarizine and griseofulvin showed uncoupling, sluggish worm movement and complete absence of ova at 100 μg/ml. In early infection, cinnarizine showed a significant reduction in the number of porto-mesenteric couples compared to the griseofulvin and control groups, a finding similar to PZQ. Remarkably, cinnarizine significantly exceeded PZQ and griseofulvin in reducing the total worm burden. In late infection, cinnarizine and griseofulvin showed results similar to PZQ by significantly reducing the numbers of hepatic and porto-mesenteric couples and total worm burden compared to controls. Cinnarizine performed better than griseofulvin by reducing hepatic and intestinal ovum counts, and it led to complete disappearance of the first two immature stages. The current work suggests the possibility of using cinnarizine and griseofulvin, mainly in late S. mansoni infection, especially cinnarizine, which showed similar results to PZQ and surpassed it in early infection. Further studies are required to elucidate their exact mechanisms of action and particularly their synergistic effect with PZQ.


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