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Advanced Biomedical Research 2020() is a protozoan parasite that infects a wide range of warm-blooded animals and humans. The conventional anti- treatments cause significant toxicity. family contains...
BACKGROUND
() is a protozoan parasite that infects a wide range of warm-blooded animals and humans. The conventional anti- treatments cause significant toxicity. family contains several medicinal plants with anti-inflammatory, chemopreventive, insecticide, antibacterial, antiviral, and antiparasitic effects. In this study, the hydroalcoholic extract of some species was investigated against .
MATERIALS AND METHODS
Seeds of , , , and aerial parts of and were extracted by maceration method using 80% ethanol. Vero cells were treated with different concentrations (5-600 μg/mL) of the extracts and pyrimethamine (as positive control), and the cellular viability was verified. Next, Vero cells were infected by tachyzoites (RH strain), and the viability of the infected cells was measured by a colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.
RESULTS
The 50% inhibitory concentration values were 5.1, 14.67, 32.49, 37.31, 71.35, and 2.63 μg/mL, and the selectivity indices were 8.06, 2.59, 0.74, 0.78, 0.65 ( < 0.05 compared with positive control), and 3.03 for , , , , , and pyrimethamine, respectively.
CONCLUSION
The results of this study demonstrated that the hydroalcoholic extracts of and have the promising anti- activity by growth inhibition of tachyzoites in infected cells.
PubMed: 32055539
DOI: 10.4103/abr.abr_206_19 -
The Lancet. Microbe May 2024Mutations in the Plasmodium falciparum dhfr gene confer resistance to pyrimethamine, which is widely used for malaria chemoprevention in Africa. We aimed to evaluate the...
Plasmodium ovale spp dhfr mutations associated with reduced susceptibility to pyrimethamine in sub-Saharan Africa: a retrospective genetic epidemiology and functional study.
BACKGROUND
Mutations in the Plasmodium falciparum dhfr gene confer resistance to pyrimethamine, which is widely used for malaria chemoprevention in Africa. We aimed to evaluate the frequency and evolution of dhfr mutations in Plasmodium ovale spp in Africa and their functional consequences, which are incompletely characterised.
METHODS
We analysed dhfr mutations and their frequencies in P ovale spp isolates collected between Feb 1, 2004, and Aug 31, 2023, from the French National Malaria Reference Centre collection and from field studies in Benin, Gabon, and Kenya. Genetic patterns of positive selection were investigated. Full-length recombinant wild-type and mutant DHFR enzymes from both P ovale curtisi and P ovale wallikeri were expressed in bacteria to test whether the most common mutations reduced pyrimethamine susceptibility.
FINDINGS
We included 518 P ovale spp samples (314 P ovale curtisi and 204 P ovale wallikeri). In P ovale curtisi, Ala15Ser-Ser58Arg was the most common dhfr mutation (39%; 124 of 314 samples). In P ovale wallikeri, dhfr mutations were less frequent, with Phe57Leu-Ser58Arg reaching 17% (34 of 204 samples). These two mutants were the most prevalent in central and east Africa and were fixed in Kenyan isolates. We detected six and four other non-synonymous mutations, representing 8% (24 isolates) and 2% (five isolates) of the P ovale curtisi and P ovale wallikeri isolates, respectively. Whole-genome sequencing and microsatellite analyses revealed reduced genetic diversity around the mutant pocdhfr and powdhfr genes. The mutant DHFR proteins showed structural changes at the pyrimethamine binding site in-silico, confirmed by a 4-times increase in pyrimethamine half-maximal inhibitory concentration in an Escherichia coli growth assay for the Phe57Leu-Ser58Arg mutant and 50-times increase for the Ala15Ser-Ser58Arg mutant, compared with the wild-type counterparts.
INTERPRETATION
The widespread use of sulfadoxine-pyrimethamine for malaria chemoprevention might have exerted fortuitous selection pressure for dhfr mutations in P ovale spp. This calls for closer monitoring of dhfr and dhps mutations in P ovale spp.
FUNDING
French Ministry of Health, Agence Nationale de la Recherche, and Global Emerging Infections Surveillance branch of the Armed Forces Health Surveillance Division.
PubMed: 38761813
DOI: 10.1016/S2666-5247(24)00054-5 -
Science Advances Mar 2023Reactivation of the latent HIV-1 reservoir is a first step toward triggering reservoir decay. Here, we investigated the impact of the BAF complex inhibitor pyrimethamine... (Randomized Controlled Trial)
Randomized Controlled Trial
Reactivation of the latent HIV-1 reservoir is a first step toward triggering reservoir decay. Here, we investigated the impact of the BAF complex inhibitor pyrimethamine on the reservoir of people living with HIV-1 (PLWH). Twenty-eight PLWH on suppressive antiretroviral therapy were randomized (1:1:1:1 ratio) to receive pyrimethamine, valproic acid, both, or no intervention for 14 days. The primary end point was change in cell-associated unspliced (CA US) HIV-1 RNA at days 0 and 14. We observed a rapid, modest, and significant increase in (CA US) HIV-1 RNA in response to pyrimethamine exposure, which persisted throughout treatment and follow-up. Valproic acid treatment alone did not increase (CA US) HIV-1 RNA or augment the effect of pyrimethamine. Pyrimethamine treatment did not result in a reduction in the size of the inducible reservoir. These data demonstrate that the licensed drug pyrimethamine can be repurposed as a BAF complex inhibitor to reverse HIV-1 latency in vivo in PLWH, substantiating its potential advancement in clinical studies.
Topics: Humans; CD4-Positive T-Lymphocytes; HIV Infections; HIV-1; Pyrimethamine; RNA; Valproic Acid; Virus Activation; Virus Latency
PubMed: 36921041
DOI: 10.1126/sciadv.ade6675 -
Frontiers in Immunology 2023In this review, we discuss a variety of immune modulating approaches that could be used to counteract tissue-damaging viral immunoinflammatory lesions which typify many... (Review)
Review
In this review, we discuss a variety of immune modulating approaches that could be used to counteract tissue-damaging viral immunoinflammatory lesions which typify many chronic viral infections. We make the point that in several viral infections the lesions can be largely the result of one or more aspects of the host response mediating the cell and tissue damage rather than the virus itself being directly responsible. However, within the reactive inflammatory lesions along with the pro-inflammatory participants there are also other aspects of the host response that may be acting to constrain the activity of the damaging components and are contributing to resolution. This scenario should provide the prospect of rebalancing the contributions of different host responses and hence diminish or even fully control the virus-induced lesions. We identify several aspects of the host reactions that influence the pattern of immune responsiveness and describe approaches that have been used successfully, mainly in model systems, to modulate the activity of damaging participants and which has led to lesion control. We emphasize examples where such therapies are, or could be, translated for practical use in the clinic to control inflammatory lesions caused by viral infections.
Topics: Humans; Models, Biological; Pyrimethamine; Sulfadiazine
PubMed: 37671156
DOI: 10.3389/fimmu.2023.1257192 -
Molecular Biology Reports Jun 2022The emergence of nonresponse or resistance to traditional chemotherapeutic agents is one of the main challenges of colorectal cancer (CRC) therapies. Thus, novel...
BACKGROUND
The emergence of nonresponse or resistance to traditional chemotherapeutic agents is one of the main challenges of colorectal cancer (CRC) therapies. Thus, novel therapeutic drugs that can improve the clinical outcomes of CRC patients are urgently needed. The purpose of this study was to investigate the effects and mechanisms of pyrimethamine in CRC.
METHODS AND RESULTS
In this study, we assessed the role of pyrimethamine on CRC cell growth by cell counting kit-8 and colony formation assays. Cell cycle distribution and cellular senescence were determined by flow cytometry and senescence-associated β-galactosidase staining respectively. RNA-seq analysis and western blotting were used to investigate the potential pathways of pyrimethamine in CRC development. Moreover, animal experiments were performed to evaluate the effect of pyrimethamine in vivo. Our results demonstrated that pyrimethamine could inhibit cell growth by inducing S phase arrest followed by cellular senescence in CRC cells, and the p38MAPK-p53 axis was probably involved in that effect. In addition, pyrimethamine could also boost CD8 T-cell mediated cytotoxicity and exert antitumor activity in vivo.
CONCLUSION
These results indicated that pyrimethamine may be a promising candidate agent for CRC treatment.
Topics: Animals; Apoptosis; CD8-Positive T-Lymphocytes; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cellular Senescence; Colorectal Neoplasms; Pyrimethamine; T-Lymphocytes
PubMed: 35262820
DOI: 10.1007/s11033-022-07262-y -
Pathogens (Basel, Switzerland) Mar 2023We have previously reported 1,2,6,7-tetraoxaspiro [7.11]nonadecane (N-89) as a promising antimalarial compound. In this study, we evaluated the effect of transdermal...
We have previously reported 1,2,6,7-tetraoxaspiro [7.11]nonadecane (N-89) as a promising antimalarial compound. In this study, we evaluated the effect of transdermal therapy (tdt) of N-89 in combination (tdct) with other antimalarials as an application for children. We prepared ointment formulas containing N-89 plus another antimalarial drug, specifically, mefloquine, pyrimethamine, or chloroquine. In a 4-day suppressive test, the ED values for N-89 alone or combined with either mefloquine, pyrimethamine, or chloroquine were 18, 3, 0.1, and 3 mg/kg, respectively. Interaction assays revealed that N-89 combination therapy showed a synergistic effect with mefloquine and pyrimethamine, but chloroquine provoked an antagonistic effect. Antimalarial activity and cure effect were compared for single-drug application and combination therapy. Low doses of tdct N-89 (35 mg/kg) combined with mefloquine (4 mg/kg) or pyrimethamine (1 mg/kg) gave an antimalarial effect but not a cure effect. In contrast, with high doses of N-89 (60 mg/kg) combined with mefloquine (8 mg/kg) or pyrimethamine (1 mg/kg), parasites disappeared on day 4 of treatment, and mice were completely cured without any parasite recurrence. Our results indicated that transdermal N-89 with mefloquine and pyrimethamine provides a promising antimalarial form for application to children.
PubMed: 36986320
DOI: 10.3390/pathogens12030398 -
The Lancet. Infectious Diseases Mar 2023Seasonal malaria chemoprevention is used in 13 countries in the Sahel region of Africa to prevent malaria in children younger than 5 years. Resistance of Plasmodium...
Prevalence of Plasmodium falciparum haplotypes associated with resistance to sulfadoxine-pyrimethamine and amodiaquine before and after upscaling of seasonal malaria chemoprevention in seven African countries: a genomic surveillance study.
BACKGROUND
Seasonal malaria chemoprevention is used in 13 countries in the Sahel region of Africa to prevent malaria in children younger than 5 years. Resistance of Plasmodium falciparum to seasonal malaria chemoprevention drugs across the region is a potential threat to this intervention.
METHODS
Between December, 2015, and March, 2016, and between December, 2017, and March, 2018, immediately following the 2015 and 2017 malaria transmission seasons, community surveys were done among children younger than 5 years and individuals aged 10-30 years in districts implementing seasonal malaria chemoprevention with sulfadoxine-pyrimethamine and amodiaquine in Burkina Faso, Chad, Guinea, Mali, Nigeria, Niger and The Gambia. Dried blood samples were collected and tested for P falciparum DNA by PCR. Resistance-associated haplotypes of the P falciparum genes crt, mdr1, dhfr, and dhps were identified by quantitative PCR and sequencing of isolates from the collected samples, and survey-weighted prevalence and prevalence ratio between the first and second surveys were estimated for each variant.
FINDINGS
5130 (17·5%) of 29 274 samples from 2016 and 2176 (7·6%) of 28 546 samples from 2018 were positive for P falciparum on quantitative PCR. Among children younger than 5 years, parasite carriage decreased from 2844 of 14 345 samples (19·8% [95% CI 19·2-20·5]) in 2016 to 801 of 14 019 samples (5·7% [5·3-6·1]) in 2018 (prevalence ratio 0·27 [95% CI 0·24-0·31], p<0·0001). Genotyping found no consistent evidence of increasing prevalence of amodiaquine resistance-associated variants of crt and mdr1 between 2016 and 2018. The dhfr haplotype IRN (consisting of 51Ile-59Arg-108Asn) was common at both survey timepoints, but the dhps haplotype ISGEAA (431Ile-436Ser-437Gly-540Glu-581Ala-613Ala), crucial for resistance to sulfadoxine-pyrimethamine, was always rare. Parasites carrying amodiaquine resistance-associated variants of both crt and mdr1 together with dhfr IRN and dhps ISGEAA occurred in 0·05% of isolates. The emerging dhps haplotype VAGKGS (431Val-436Ala-437Gly-540Lys-581Gly-613Ser) was present in four countries.
INTERPRETATION
In seven African countries, evidence of a significant reduction in parasite carriage among children receiving seasonal malaria chemoprevention was found 2 years after intervention scale-up. Combined resistance-associated haplotypes remained rare, and seasonal malaria chemoprevention with sulfadoxine-pyrimethamine and amodiaquine is expected to retain effectiveness. The threat of future erosion of effectiveness due to dhps variant haplotypes requires further monitoring.
FUNDING
Unitaid.
Topics: Child; Humans; Plasmodium falciparum; Amodiaquine; Haplotypes; Antimalarials; Seasons; Prevalence; Pyrimethamine; Sulfadoxine; Malaria; Malaria, Falciparum; Drug Combinations; Chemoprevention; Nigeria; Tetrahydrofolate Dehydrogenase; Genomics; Drug Resistance
PubMed: 36328000
DOI: 10.1016/S1473-3099(22)00593-X -
Malaria Journal Oct 2022Resistance to anti-malarial drugs is associated with polymorphisms in target genes and surveillance for these molecular markers is important to detect the emergence of...
Molecular surveillance for anti-malarial drug resistance and genetic diversity of Plasmodium falciparum after chloroquine and sulfadoxine-pyrimethamine withdrawal in Quibdo, Colombia, 2018.
BACKGROUND
Resistance to anti-malarial drugs is associated with polymorphisms in target genes and surveillance for these molecular markers is important to detect the emergence of mutations associated with drug resistance and signal recovering sensitivity to anti-malarials previously used.
METHODS
The presence of polymorphisms in genes associated with Plasmodium falciparum resistance to chloroquine and sulfadoxine-pyrimethamine was evaluated by Sanger sequencing, in 85 P. falciparum day of enrollment samples from a therapeutic efficacy study of artemether-lumefantrine conducted in 2018-2019 in Quibdo, Colombia. Samples were genotyped to assess mutations in pfcrt (codons 72-76), pfdhfr (codons 51, 59, 108, and 164), and pfdhps genes (codons 436, 437, 540, and 581). Further, the genetic diversity of infections using seven neutral microsatellites (NMSs) (C2M34, C3M69, Poly α, TA1, TA109, 2490, and PfPK2) was assessed.
RESULTS
All isolates carried mutant alleles for pfcrt (K76T and N75E), and for pfdhfr (N51I and S108N), while for pfdhps, mutations were observed only for codon A437G (32/73, 43.8%). Fifty samples (58.8%) showed a complete neutral microsatellites (NMS) profile. The low mean number of alleles (2 ± 0.57) per locus and mean expected heterozygosity (0.17 ± 0.03) showed a reduced genetic diversity. NMS multilocus genotypes (MMG) were built and nine MMG were identified.
CONCLUSIONS
Overall, these findings confirm the fixation of chloroquine and pyrimethamine-resistant alleles already described in the literature, implying that these drugs are not currently appropriate for use in Colombia. In contrast, mutations in the pfdhps gene were only observed at codon 437, an indication that full resistance to sulfadoxine has not been achieved in Choco. MMGs found matched the clonal lineage E variant 1 previously reported in northwestern Colombia.
Topics: Humans; Sulfadoxine; Pyrimethamine; Antimalarials; Plasmodium falciparum; Chloroquine; Colombia; Malaria, Falciparum; Artemether; Artemether, Lumefantrine Drug Combination; Drug Combinations; Drug Resistance; Polymorphism, Genetic; Codon
PubMed: 36307852
DOI: 10.1186/s12936-022-04328-x -
SAGE Open Medicine 2022The study examined the differentials in prevalence and correlates on the uptake of tetanus toxoid and intermittent preventive treatment of malaria among pregnant women...
Differentials in prevalence and correlates on uptake of tetanus toxoid and intermittent preventive treatment with sulfadoxine-pyrimethamine during pregnancy: A community-based cross-sectional study in The Gambia.
OBJECTIVES
The study examined the differentials in prevalence and correlates on the uptake of tetanus toxoid and intermittent preventive treatment of malaria among pregnant women in The Gambia.
METHODS
The 2018 data from The Gambia Multiple Indicators Cluster Survey were analyzed. Data from 6143 women of reproductive age who have given birth were extracted for the analysis. Percentages and Chi-square tests were used. In addition, a multivariable logistic regression model was used to calculate the adjusted odds ratios (with a corresponding 95% confidence interval). The level of significance was set at < 0.05.
RESULTS
The prevalence of tetanus toxoid uptake among women in The Gambia was 88.2%, while that of the adequate tetanus toxoid doses was 34.8%. The prevalence of intermittent preventive treatment with sulfadoxine-pyrimethamine uptake among maternal women in The Gambia was 98.6%, while that of the adequate intermittent preventive treatment with sulfadoxine-pyrimethamine doses taken was 34.3%. The identified statistically significant covariates of tetanus toxoid immunization and intermittent preventive treatment with sulfadoxine-pyrimethamine uptake includes women's age, local government areas, parity, use of radio, use of newspaper, and antenatal care visits.
CONCLUSION
The current utilization rate for adequate intermittent preventive treatment with sulfadoxine-pyrimethamine and tetanus toxoid immunization during pregnancy in The Gambia is very low and even below universal levels. The country needs to strengthen more and effective mass media advocacy programs that would target both rural and urban populace, and motivate maternal women to ensure adequate vaccination against malaria and tetanus.
PubMed: 35024140
DOI: 10.1177/20503121211065908 -
The Journal of Biological Chemistry Feb 2022Cancer is often characterized by aberrant gene expression patterns caused by the inappropriate activation of transcription factors. Signal transducer and activator of...
Cancer is often characterized by aberrant gene expression patterns caused by the inappropriate activation of transcription factors. Signal transducer and activator of transcription 3 (STAT3) is a key transcriptional regulator of many protumorigenic processes and is persistently activated in many types of human cancer. However, like many transcription factors, STAT3 has proven difficult to target clinically. To address this unmet clinical need, we previously developed a cell-based assay of STAT3 transcriptional activity and performed an unbiased and high-throughput screen of small molecules known to be biologically active in humans. We identified the antimicrobial drug pyrimethamine as a novel and specific inhibitor of STAT3 transcriptional activity. Here, we show that pyrimethamine does not significantly affect STAT3 phosphorylation, nuclear translocation, or DNA binding at concentrations sufficient to inhibit STAT3 transcriptional activity, suggesting a potentially novel mechanism of inhibition. To identify the direct molecular target of pyrimethamine and further elucidate the mechanism of action, we used a new quantitative proteome profiling approach called proteome integral solubility alteration coupled with a metabolomic analysis. We identified human dihydrofolate reductase as a target of pyrimethamine and demonstrated that the STAT3-inhibitory effects of pyrimethamine are the result of a deficiency in reduced folate downstream of dihydrofolate reductase inhibition, implicating folate metabolism in the regulation of STAT3 transcriptional activity. This study reveals a previously unknown regulatory node of the STAT3 pathway that may be important for the development of novel strategies to treat STAT3-driven cancers.
Topics: Anti-Infective Agents; Cell Line, Tumor; Folic Acid; Humans; Proteome; Pyrimethamine; STAT3 Transcription Factor; Tetrahydrofolate Dehydrogenase
PubMed: 34953855
DOI: 10.1016/j.jbc.2021.101531