Antifolate Research Articles

BONCAT-iTRAQ Labelling Reveals Molecular Markers of Adaptive Responses in Toxoplasma gondii to Pyrimethamine Treatment.

We employed a BONCAT-iTRAQ labelling approach to investigate newly synthesised proteins (NSPs) in Toxoplasma gondii subjected to varying concentrations of the antifolate drug pyrimethamine. Our results reveal that numerous NSPs exhibited altered expression levels in response to the drug, with significant upregulation observed at higher concentrations. Key proteins involved in protein synthesis, stress responses, energy metabolism, and cytoskeletal dynamics were identified, indicating that T. gondii undergoes complex adaptive responses to pyrimethamine treatment. While some of the identified pathways reflect a generic stress response, this study provides important molecular markers and mechanistic insights specific to the parasite's adaptation strategies. These findings contribute to understanding how T. gondii modulates its proteome in response to drug-induced stress and lay the groundwork for further investigations into potential therapeutic targets.

Oral pre-treatment with Citronellol ameliorates Methotrexate-induced nephrotoxicity in Wistar rats via targeting oxidative stress and inflammation

Background Methotrexate (MTX) is a classical folic acid antagonist widely used in the treatment of malignant and non-malignant disorders. However, its clinical application is often restricted by concomitant adverse effects, including renal damage. Numerous studies have highlighted the role of oxidative stress and inflammation in mediating MTX-related nephrotoxicity. Therefore, the current study aimed to explore the possible renoprotective action of Citronellol (CT), a natural compound with prominent antioxidant and anti-inflammatory activities, against nephrotoxicity induced by MTX. Methods To fulfill our objective, 24 adult male Wistar rats were randomly allocated into four groups: control, MTX, 100 mg/kg CT plus MTX and 200 mg/kg CT plus MTX. At the end of the study, the experimental rats were anesthetized, blood samples were collected for biochemical assays, and the kidneys were surgically removed for biochemical and gene expression analyses, after which all rats were sacrificed by exsanguination. Results Compared to the MTX-treated group, our results revealed that pre-supplementation with 100 or 200 mg/kg CT remarkably ameliorated renal damage biomarkers, including serum urea, serum creatinine, and kidney injury molecule-1 (KIM-1). In addition, pre-treatment with 100 or 200 mg/kg CT enhanced the activity of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx), diminished renal malondialdehyde (MDA) contents, and attenuated inflammation by suppressing renal nuclear factor kappa B (NF-κB) signaling and diminishing tumor necrosis factor-alpha (TNF-α) gene expression. Moreover, pre-treatment with 200 mg/kg CT markedly reduced interleukin-1 beta (IL-1β) gene expression. Conclusion Our findings demonstrate, for the first time, that CT can serve as a new promising agent for mitigating nephrotoxicity induced by MTX through its antioxidant and anti-inflammatory properties.

Whole genome sequencing of multidrug-resistant Klebsiella pneumoniae from poultry in Noakhali, Bangladesh: Assessing risk of transmission to humans in a pilot study

BackgroundMulti-drug resistant (MDR) Klebsiella pneumoniae is a public health concern due to its presence in Bangladeshi poultry products and its ability to spread resistance genes. This study genetically characterizes a distinct MDR K. pneumoniae isolate from the gut of poultry in Noakhali, Bangladesh, offering insights into its resistance mechanisms and public health impact. MethodsKlebsiella pneumoniae isolates from broiler and layer poultry were identified using biochemical and molecular analyses. Eleven isolates were tested for antibiotic sensitivity and categorized by their Multiple Antibiotic Resistance Index (MARI) profiles. The isolate with the highest MARI was selected for whole-genome sequencing using Illumina technology. The sequencing data were analyzed for genome annotation, pan-genome analysis, genome similarities, sequence type identification, and the identification of genetic determinants of resistance and virulence genes. ResultWe identified 10 MARI profiles among 11 K. pneumoniae isolates, with values ranging from 0.64 to 0.94. The highest MARI of 0.94 was found in an isolate from a layer poultry. This isolate's genome, 5401,789 base pairs long with 89.6 % coverage, showed potential inter-species dissemination, as indicated by core genome phylogenetic analysis. It possessed genes conferring resistance to fluoroquinolones, aminoglycosides, β-lactams, folate pathway antagonists, fosfomycin, macrolides, quinolones, rifamycin, tetracyclines, and polymyxins, including colistin. ConclusionPoultry serve as reservoirs for MDR K. pneumoniae, which can spread to other species and pose significant health risks. Rigorous monitoring of antibiotic use and genetic characterization of MDR bacterial isolates are essential to mitigate this threat.

Late-life dietary folate restriction reduces biosynthesis without compromising healthspan in mice.

Folate is a vitamin required for cell growth and is present in fortified foods in the form of folic acid to prevent congenital abnormalities. The impact of low-folate status on life-long health is poorly understood. We found that limiting folate levels with the folate antagonist methotrexate increased the lifespan of yeast and worms. We then restricted folate intake in aged mice and measured various health metrics, metabolites, and gene expression signatures. Limiting folate intake decreased anabolic biosynthetic processes in mice and enhanced metabolic plasticity. Despite reduced serum folate levels in mice with limited folic acid intake, these animals maintained their weight and adiposity late in life, and we did not observe adverse health outcomes. These results argue that the effectiveness of folate dietary interventions may vary depending on an individual's age and sex. A higher folate intake is advantageous during the early stages of life to support cell divisions needed for proper development. However, a lower folate intake later in life may result in healthier aging.

The Risk Of Birth Defects From Folic Acid Antagonists During Pregnant

The Risk Of Birth Defects From Folic Acid Antagonists During Pregnant

Blue light emitting graphene quantum dots/ Rhodamine B doped gold nanostars for ratiometric detection of methotrexate

In this work, an innovative ratiometric sensing platform was developed for the determination of methotrexate (MTX), an antifolate drug, a chemotherapy agent, and an immune system suppressant based on blue emission graphene quantum dots/Rhodamine B doped gold nanostars (B-GQDs/Au NSt-RB). The developed sensor was a dual-emission fluorescent probe with two major emission peaks at 440 nm (B-GQDs) and 580 nm (Au NSt-RB) by exciting at 330 nm. Based on the inhibiting effect of MTX on the system's fluorescence density, the stable ratiometric fluorescent probe was used for the rapid determination of MTX in aquatic solutions and spiked human serum samples. The results indicated good linear correlations over the logarithmic concentration range of 0.3 nM–50.0 μM. In addition, B-GQDs/Au NSt-RB can further realize highly sensitive detection of MTX with a low LOD value of 2.28 × 10−10 M. The RSD% values obtained for the intra-day and inter-day precision were 0.63–3.86 %. With recoveries of 98.2–100.1 % and 98.7–100.5 %, respectively. The short-term temperature and freeze-thaw tests confirmed the higher stability of the developed sensor. In addition, the calculated recoveries for MTX recognition in real samples were in the range of 98–102 %. These findings suggested the excellent potential of the ratiometric fluorescence B-GQDs/Au NSt-RB sensor for detecting MTX in real plasma samples.

Anticancer Activity of Imidazolyl Gold(I/III) Compounds in Non-Small Cell Lung Cancer Cell Lines.

Lung cancer is a leading cause of cancer-related death worldwide that needs updated therapies to contrast both the serious side effects and the occurrence of drug resistance. A panel of non-small cell lung cancer (NSCLC) cells were herein employed as cancer models. Eight structurally related gold(I) and gold(III) complexes with NHC and halides or triphenylphosphane ligands were investigated as lung cancer cell growth inhibitors. As expected, gold compounds with PPh3 were found to be more cytotoxic than homoleptic [(NHC)2-Au(I)]X or heteroleptic NHC-Au(I)X or NHC-Au(III)X3 complexes. Mixed ligand gold(I) compounds exhibiting the linear NHC-AuPPh3 (compound 7) or the trigonal NHC-Au(Cl)PPh3 (compound 8) arrangements at the central metal were found to be the best lung cancer cytotoxic compounds. Analysis of the TrxR residual activity of the treated cells revealed that these compounds efficiently inhibit the most accredited molecular target for gold compounds, the TrxR, with compound 8 reaching more than 80% activity reduction in lung cells. Some of the current cancer lung therapy protocols consist of specific lung cancer cell cytotoxic agents combined with antifolate drugs; interestingly, the herein gold compounds are both TrxR and antifolate inhibitors. The human DHFR was inhibited with IC50 ranging between 10-21 µM, depending on substrate concentrations, proceeding by a likely allosteric mechanism only for compound 8.

Unveiling the Therapeutic Potential of Folate-Dependent One-Carbon Metabolism in Cancer and Neurodegeneration.

Cellular metabolism is crucial for various physiological processes, with folate-dependent one-carbon (1C) metabolism playing a pivotal role. Folate, a B vitamin, is a key cofactor in this pathway, supporting DNA synthesis, methylation processes, and antioxidant defenses. In dividing cells, folate facilitates nucleotide biosynthesis, ensuring genomic stability and preventing carcinogenesis. Additionally, in neurodevelopment, folate is essential for neural tube closure and central nervous system formation. Thus, dysregulation of folate metabolism can contribute to pathologies such as cancer, severe birth defects, and neurodegenerative diseases. Epidemiological evidence highlights folate's impact on disease risk and its potential as a therapeutic target. In cancer, antifolate drugs that inhibit key enzymes of folate-dependent 1C metabolism and strategies targeting folate receptors are current therapeutic options. However, folate's impact on cancer risk is complex, varying among cancer types and dietary contexts. In neurodegenerative conditions, including Alzheimer's and Parkinson's diseases, folate deficiency exacerbates cognitive decline through elevated homocysteine levels, contributing to neuronal damage. Clinical trials of folic acid supplementation show mixed outcomes, underscoring the complexities of its neuroprotective effects. This review integrates current knowledge on folate metabolism in cancer and neurodegeneration, exploring molecular mechanisms, clinical implications, and therapeutic strategies, which can provide crucial information for advancing treatments.

First identification and genomic features of multidrug-resistant Citrobacter freundii ST669 strain isolated from a domesticated duck in Bangladesh

ObjectivesCitrobacter freundii is a prevalent source of nosocomial infections and a well-known cause of diarrheal diseases. In recent years, it has also become increasingly resistant to various antimicrobials. In this study, we screened and characterized a multidrug-resistant (MDR) C. freundii isolate obtained from a domesticated diseased duck to better understand the genetic features, molecular epidemiology, and underlying factors linked to the antimicrobial resistance genes (ARGs) and virulence factor genes (VFGs) of the isolate. MethodsThe C. freundii BAU_TM8 strain was isolated using culturing, staining, biochemical, polymerase chain reaction, and Matrix-assisted laser desorption/ionization-time of flight methods. The MDR properties of the strain were determined by a disk diffusion test. The genomic sequence of C. freundii BAU_TM8 was performed using the Illumina NextSeq2000 platform. The ARGs, VFGs, and genomic functional characteristics of the C. freundii BAU_TM8 strain were identified using several open-source databases. ResultsThe sequence type of this strain was ST669, and the pathogenicity index of the strain was 0.919. Moreover, the strain had an estimated genome length of 5,797,806 bp, harboring 62 contigs, a G + C content of 54.32 %, and five contig L50s with an N50 value of 443,947 bp. Using phylogenetic analysis, this strain was closely related to two strains isolated from human and environmental samples in the USA and China despite huge geographical distances. The C. freundii BAU_TM8 strain consisted of 40 AGRs encoding resistance to 19 antimicrobial categories, e.g., fluoroquinolones, macrolides, folate pathway antagonists, aminoglycosides, tetracyclines, cephalosporins, and others. According to the phenotypic assay and genome sequence, the sensitivity and specificity of resistance profiles of the strain were 100 % and 20 %, respectively. Moreover, the virulence factor database detected 66 VFGs in this strain. This strain contained 1581 subsystems, having 33 % subsystem coverage and 2275 genes encoding amino acid derivatives, carbohydrate metabolism, protein metabolism, cofactors, vitamins, prosthetic groups, pigments, respiration, motility and chemotaxis, stress response, DNA metabolism, nucleosides and nucleotides, and others. ConclusionsTo the best of our knowledge, this is the first WGS report of C. freundii from a domesticated duck in Bangladesh. The ubiquitous occurrence of ARGs and VFGs in the C. freundii BAU_TM8 strain detected in this study highlights the growing concern about antimicrobial resistance in humans, animals, and environments.

Atherogenic Effect of Homocysteine, a Biomarker of Inflammation and Its Treatment

AbstractHyperhomocysteinemia (HHcy) is an independent risk factor for atherosclerosis. Ischemic stroke and heart disease, coronary heart disease, and cardiovascular disease are events resulting from long-lasting and silent atherosclerosis. This paper deals with the synthesis of homocysteine (Hcy), causes of HHcy, mechanism of HHcy-induced atherosclerosis, and treatment of HHcy. Synthesis and metabolism of Hcy involves demethylation, transmethylation, and transsulfuration, and these processes require vitamin B6 and vitamin B12 folic acid (vitamin B9). Causes of HHcy include deficiency of vitamins B6, B9, and B12, genetic defects, use of smokeless tobacco, cigarette smoking, alcohol consumption, diabetes, rheumatoid arthritis, low thyroid hormone, consumption of caffeine, folic acid antagonist, cholesterol-lowering drugs (niacin), folic acid antagonist (phenytoin), prolonged use of proton pump inhibitors, metformin, and hypertension. HHcy-induced atherosclerosis may be mediated through oxidative stress, decreased availability of nitric oxide (NO), increased expression of monocyte chemoattractant protein-1, smooth muscle cell proliferation, increased thrombogenicity, and induction of arterial connective tissue. HHcy increases the generation of atherogenic biomolecules such as nuclear factor-kappa B, proinflammatory cytokines (IL-1β, IL-6, and IL-8), cell adhesion molecules (intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selection), growth factors (IGF-1 and TGF-β), and monocyte colony-stimulating factor which lead to the development of atherosclerosis. NO which is protective against the development of atherosclerosis is reduced by HHcy. Therapy with folic acid, vitamin B6, and vitamin B12 lowers the levels of Hcy, with folic acid being the most effective. Dietary sources of folic acid, vitamin B6, vitamin B12, omega-3 fatty acid, and green coffee extract reduce Hcy. Abstaining from drinking coffee and alcohol, and smoking also reduces blood levels of Hcy. In conclusion, HHcy induces atherosclerosis by generating atherogenic biomolecules, and treatment of atherosclerosis-induced diseases may be by reducing the levels of Hcy.

Therapeutic Applications and Challenges of a Widely Used Antifolate Drug

Introduction and purpose: Methotrexate (MTX) is an antifolate metabolite that interferes with the synthesis and repair of DNA and with cell replication. It has anti-inflammatory and immunomodulatory properties and was first used in 1951 for the treatment of RA and psoriasis. Methotrexate (4-amino-10-methylfolic acid, MTX) is a popular disease-modifying drug for the treatment of rheumatoid arthritis, psoriasis and leukaemia. MTX is an antagonist of folic acid, primarily through inhibition of the proliferative effect. MTX and its metabolites are associated with many serious adverse effects, including gastrointestinal and hepatic toxicity, myelosuppression, stomatitis, etc. Taking methotrexate may contribute to a reduction in the quality of life for patients. Additionally, long-term use of methotrexate requires regular monitoring, which can be burdensome and stressful for patients. In this context, different approaches have been used to improve the therapeutic properties of MTX and to reduce its adverse effects. The long history of the drug has made it possible to assess its efficacy and to collect data on adverse events, including potentially life-threatening adverse events. This article aims to provide a literature-based overview of current knowledge about methotrexate in clinical practice. Materials and Methods: Review and summary of research studies available in open-source format on Google Scholar, PubMed. Conclusion: The result is a picture of methotrexate as a drug that is used for many conditions, but is associated with many side effects that can be a significant problem for patients and healthcare professionals.

Phosphodiesterase Inhibition to Sensitize Non-Small-Cell Lung Cancer to Pemetrexed: A Double-Edged Strategy.

Phosphosidesterases (PDEs) are key regulators of cyclic nucleotide signaling, controlling many hallmarks of cancer and playing a role in resistance to chemotherapy in non-small-cell lung cancer (NSCLC). We evaluated the anti-tumor activity of the anti-folate agent pemetrexed (PMX), alone or combined with biochemical inhibitors of PDE5, 8, 9, or 10, against squamous and non-squamous NCSLC cells. Genomic alterations to PDE genes (PDEmut) or PDE biochemical inhibition (PDEi) can sensitize NSCLC to PMX in vitro (observed in 50% NSCLC evaluated). The synergistic activity of PDEi with PMX required microdosing of the anti-folate drug. As single agents, none of the PDEis evaluated have anti-tumor activity. PDE biochemical inhibitors, targeting either cAMP or cGMP signaling (or both), resulted in significant cross-modulation of downstream pathways. The use of PDEi may present a new strategy to overcome PMX resistance of PDEwt NSCLC tumors but comes with important caveats, including the use of subtherapeutic PMX doses.

Disturbed intracellular folate homeostasis impairs autophagic flux and increases hepatocytic lipid accumulation

BackgroundMetabolic associated fatty liver disease (MAFLD), a prevalent liver disorder affecting one-third of the global population, encompasses a spectrum ranging from fatty liver to severe hepatic steatosis. Both genetic and lifestyle factors, particularly diet and nutrition, contribute to its etiology. Folate deficiency, a frequently encountered type of malnutrition, has been associated with the pathogenesis of MAFLD and shown to impact lipid deposition. However, the underlying mechanisms of this relationship remain incompletely understood. We investigated the impact of disturbed folate-mediated one-carbon metabolism (OCM) on hepatic lipid metabolism both in vitro using human hepatoma cells and in vivo using transgenic fluorescent zebrafish displaying extent-, stage-, and duration-controllable folate deficiency upon induction.ResultsDisturbed folate-mediated one-carbon metabolism, either by inducing folate deficiency or adding anti-folate drug, compromises autophagy and causes lipid accumulation in liver cells. Disturbed folate status down-regulates cathepsin L, a key enzyme involved in autophagy, through inhibiting mTOR signaling. Interfered mitochondrial biology, including mitochondria relocation and increased fusion-fission dynamics, also occurs in folate-deficient hepatocytes. Folate supplementation effectively mitigated the impaired autophagy and lipid accumulation caused by the inhibition of cathepsin L activity, even when the inhibition was not directly related to folate deficiency.ConclusionsDisruption of folate-mediated OCM diminishes cathepsin L expression and impedes autophagy via mTOR signaling, leading to lipid accumulation within hepatocytes. These findings underscore the crucial role of folate in modulating autophagic processes and regulating lipid metabolism in the liver.

Multi-Gene Single Nucleotide Polymorphism Detection in Gastric Cancer Based on Ion Semiconductor Sequencing Platform.

Gastric cancer is a common heterogeneous tumor. Most patients have advanced gastric cancer at the time of diagnosis and often need chemotherapy. Although 5-fluorouracil (5-FU) is widely used for treatment, its therapeutic sensitivity and drug tolerance still need to be determined, which emphasizes the importance of individualized administration. Pharmacogenetics can guide the clinical implementation of individualized treatment. Single nucleotide polymorphisms (SNPs), as a genetic marker, contribute to the selection of appropriate chemotherapy regimens and dosages. Some SNPs are associated with folate metabolism, the therapeutic target of 5-FU. Methylenetetrahydrofolate reductase (MTHFR) rs1801131 and rs1801133, dihydrofolate reductase (DHFR) rs1650697 and rs442767, methionine synthase (MTR) rs1805087, gamma-glutamyl hydrolase (GGH) rs11545078 and solute carrier family 19 member 1 (SLC19A1) rs1051298 have been investigated in different kinds of cancers and antifolate antitumor drugs, which have potential forecasting and guiding significance for application of 5-FU. The ion torrent next-generation semiconductor sequencing technology can rapidly detect gastric cancer-related SNPs. Each time a base is extended in a DNA chain, an H+ will be released, causing local pH changes. The ionic sensor detects pH changes and converts chemical signals into digital signals, achieving sequencing by synthesis. This technique has low sample requirement, simple operation, low cost, and fast sequencing speed, which is beneficial for guiding individualized chemotherapy by SNPs.

1,2,4,5-Tetraoxane derivatives/hybrids as potent antimalarial endoperoxides: Chronological advancements, structure-activity relationship (SAR) studies and future perspectives.

Malaria is a life-threatening disease that affects tropical and subtropical regions worldwide. Various drugs were used to treat malaria, including artemisinin and derivatives, antibiotics (tetracycline, doxycycline), quinolines (chloroquine, amodiaquine), and folate antagonists (sulfadoxine and pyrimethamine). Since the malarial parasites developed drug resistance, there is a need to develop new chemical entities with high efficacy and low toxicity. In this context, 1,2,4,5-tetraoxanes emerged as an essential scaffold and have shown promising antimalarial activity. To improve activity and overcome resistance to various antimalarial drugs; 1,2,4,5-tetraoxanes were fused with various aryl/heteroaryl/alicyclic/spiro moieties (steroid-based 1,2,4,5-tetraoxanes, triazine-based 1,2,4,5-tetraoxanes, aminoquinoline-based 1,2,4,5-tetraoxanes, dispiro-based 1,2,4,5-tetraoxanes, piperidine-based 1,2,4,5-tetraoxanes and diaryl-based 1,2,4,5-tetraoxanes). The present review aims to focus on covering the relevant literature published during the past 30 years (1992-2022). We summarize the most significant in vitro, in vivo results and structure-activity relationship studies of 1,2,4,5-tetraoxane-based hybrids as antimalarial agents. The structural evolution of different hybrids can provide the framework for the future development of 1,2,4,5-tetraoxane-based hybrids to treat malaria.

Direct radiolabeling of methotrexate and methotrexate micelles with Tc-99m using QbD approach

The aim of the work presented in this manuscript was to radiolabel methotrexate and prepare radiolabeled methotrexate micelles, an antifolate drug with Tc-99m using QbD approach. The radiolabeling was executed using the experimental design and the radiolabeled drug was further encapsulated in micelles. The authors are of the view that the radiolabeled MTX could be used to target the folate receptor overexpressing cancers such as the kidney, colorectal, breast, brain etc thereby opening newer possibilities to the theranostic applications of the formed conjugate.

Valsartan Mitigates the Progression of Methotrexate-Induced Acute Kidney Injury in Rats via the Attenuation of Renal Inflammation and Oxidative Stress.

Methotrexate (MTX) is a folic acid antagonist, commonly administered for the treatment of a variety of cancers. However, methotrexate toxicity including bone marrow suppression and hepatic and renal toxicity limits its use. Angiotensin AT1 receptor blockers including Valsartan (Val) possess the ability to ameliorate MTX-induced toxicity through various mechanisms. In this study, we explored the potential reno-protective effects of Val against MTX-induced acute kidney injury in rats. Twenty-four Wistar rats were randomly segregated into 3 groups. Group 1 served as the control group and received an oral dose of 1mL/kg of normal saline. Group 2 received a single dose of 20 mg/kg of MTX intraperitoneally (IP) for 5 days. Group 3 received a single IP dose of 20 mg/kg of MTX followed by an oral dose of 10 mg/kg of Valsartan for 5 days. At the end of the experiment, the levels of serum kidney biomarkers, inflammatory and oxidative stress markers were accessed. Furthermore, the effect of MTX on kidney tissue histology was examined. Our results showed that MTX treatment increased the level of serum kidney and inflammatory biomarkers and decreased the level of antioxidants SOD and GSH while increasing the lipid peroxidation contents. Furthermore, MTX treatment caused structural changes to kidney histology. However, the administration of Val significantly prevented these changes. Valsartan possesses nephroprotective potential and might serve as a potential therapeutic strategy against MTX-induced kidney injury.

A Review of Some the Physiological Effects of Methotrexate on Rheumatoid Arthritis

Rheumatoid arthritis is one of the most prevalent autoimmune diseases at the present time, and it affects both sexes and is characterized by the incidence of women more than men about 1:3. Arthritis causes many negative effects in the various body systems, represented by the lymphatic, respiratory, muscular and blood systems, in addition to its effect on the heart, blood vessels and kidneys. Cytokines have an important role in stimulating the occurrence of rheumatoid arthritis, and these cytokines (IL-1, TNF-α, IL-8) attract inflammatory cells to the synovial membrane due to the erosion of bones and joints. Amethopterin, 4-amino 4-deoxy-N10-methylpteroyl-glutamic acid is a folate antagonist) developed more than 50 years ago in combination with several antifolate therapies used to fight malignant tumors. This review study Further elucidation of the mechanism of methotrexate to treat RA in the patients Methotrexate remains the mainstay of RA treatment and it important to identify the patients in whom the drug is effective and those in which toxicity may be an issue. Genetic and biomarkers may help to stratify patients and possibly shed light on the mechanism for efficacy and for toxicity of methotrexate for RA.

Maternal exposure to folate antagonists and susceptibility to congenital heart disease in offspring: A systematic review and meta-analysis.

The objective of this meta-analysis was to determine whether maternal exposure to folate antagonists is associated with increased rates of congenital heart disease in offspring. A comprehensive search for articles in the MEDLINE (PubMed) and EMBASE databases published up to 21 August 2023 was performed. The search strategy was not limited by study design but only for articles in the English language. Analysis of 6 cohort studies and 5 cross-sectional studies, published between 1976 and 2020, showed significant increase in rate of congenital heart disease (odds ratio 1.55, 95% confidence interval, 1.28-1.87) when exposed to folate antagonists compared with the control. Further subgroup analysis showed the increased rate for exposure to both dihydrofolate reductase inhibitors and antiepileptic drugs separately. No differences were observed when analyses were stratified by timing of study. Administration of folate antagonists within the 12-week period preceding conception and throughout the second and third months of gestation exhibited a statistically significant elevation in the susceptibility to congenital heart diseases. Notably, the protective effect of folic acid supplementation was reported in cases of congenital heart disease linked to dihydrofolate reductase inhibitors but not that associated with antiepileptic drugs.

Repurposing FDA-approved drugs to target malaria through inhibition of dihydrofolate reductase in the folate biosynthesis pathway: A prospective approach.

Dihydrofolate reductase (DHFR) is a ubiquitous enzyme that regulates the biosynthesis of tetrahydrofolate among various species of Plasmodium parasite. It is a validated target of the antifolate drug pyrimethamine (Pyr) in Plasmodium falciparum (Pf), but its clinical efficacy has been hampered due to the emergence of drug resistance. This has made the attempt to screen Food & Drug Administration-approved drugs against wild- and mutantPfDHFR by employing an in-silico pipeline to identify potent candidates. The current study has followed a virtual screening approach for identifying potential DHFR inhibitors from DrugBank database, based on a structure similarity search of candidates, followed by absorption, distribution, metabolism, and excretion estimation. The screened drugs were subjected to various parameters like docking, molecular mechanics with generalized born and surface area solvation calculations, and molecular simulations. We have thus identified twopotential drug candidates, duloxetine and guanethidine, which can be repurposed to be tested for their efficacy against wild type and drug resistant falciparum malaria.