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Biochimica Et Biophysica Acta.... Apr 2023Staphylococcus aureus is an opportunistic pathogen and one of the most frequent causes for community acquired and nosocomial bacterial infections. Even so, its energy...
Staphylococcus aureus is an opportunistic pathogen and one of the most frequent causes for community acquired and nosocomial bacterial infections. Even so, its energy metabolism is still under explored and its respiratory enzymes have been vastly overlooked. In this work, we unveil the dihydroorotate:quinone oxidoreductase (DHOQO) from S. aureus, the first example of a DHOQO from a Gram-positive organism. This protein was shown to be a FMN containing menaquinone reducing enzyme, presenting a Michaelis-Menten behaviour towards the two substrates, which was inhibited by Brequinar, Leflunomide, Lapachol, HQNO, Atovaquone and TFFA with different degrees of effectiveness. Deletion of the DHOQO coding gene (Δdhoqo) led to lower bacterial growth rates, and effected in cell morphology and metabolism, most importantly in the pyrimidine biosynthesis, here systematized for S. aureus MW2 for the first time. This work unveils the existence of a functional DHOQO in the respiratory chain of the pathogenic bacterium S. aureus, enlarging the understanding of its energy metabolism.
Topics: Atovaquone; Electron Transport; Quinones; Staphylococcus aureus; Quinone Reductases
PubMed: 36481274
DOI: 10.1016/j.bbabio.2022.148948 -
Journal of Parasitic Diseases :... Dec 2022This survey designed to assess the in vitro and in vivo activity of α-pinene, a monoterpene commonly originated in essential oils on . The in vitro effect of various...
This survey designed to assess the in vitro and in vivo activity of α-pinene, a monoterpene commonly originated in essential oils on . The in vitro effect of various concentration of α-pinene against tachyzoites of Rh strain was assessed by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The activity of α-pinene on the stimulation of apoptosis in tachyzoites of was also examined using the caspase 3 colorimetric activity assay. In vivo assay, mice were orally received α-pinene at 2 and 4 mg/kg/day for 14 days, then, pre-treated mice were daily tested and the rate of death was recorded. α-pinene meaningfully declined ( < 0.001) the tachyzoites viability with the IC value of 23.3 µg/mL. α-pinene induced the apoptosis through increasing the caspase-3 activity by 35.6%. Oral treatment with α-pinene significantly ( < 0.01) improved the survival rate infected mice with by 9th day. α-pinene + atovauone (50 mg/kg) significantly ( < 0.01) improved the survival rate infected mice up to 11 days compared with the control groups. α-pinene especially in combined atovaquone at 50 mg/kg for 2 weeks meaningfully ( < 0.05) declined oxidative stress. We found the promising in vitro anti- effects of α-pinene on RH strain. In addition, we found that α-pinene therapy particularly along with the reference drug declined the mortality rate of infected mice. Although, we just confirmed the stimulation of apoptosis and anti-inflammatory effects as the main anti- mechanisms of α-pinene; however, more surveys concerning the accurate mechanisms, toxicity, and efficacy on other strains are required to confirm these results.
PubMed: 36457783
DOI: 10.1007/s12639-022-01514-1 -
Frontiers in Cellular and Infection... 2022Human babesiosis is a global emerging tick-borne disease caused by infection with intra-erythrocytic parasites of the genus . With the rise in human babesiosis cases,...
Human babesiosis is a global emerging tick-borne disease caused by infection with intra-erythrocytic parasites of the genus . With the rise in human babesiosis cases, the discovery and development of new anti- drugs are essential. Phosphatidylinositol 4-kinase (PI4K) is a widely present eukaryotic enzyme that phosphorylates lipids to regulate intracellular signaling and trafficking. Previously, we have shown that MMV390048, an inhibitor of PI4K, showed potent inhibition against species, revealing PI4K as a druggable target for babesiosis. However, twice-administered, 7-day regimens failed to clear parasites from the immunocompromised host. Hence, in this study, we wanted to clarify whether targeting PI4K has the potential for the radical cure of babesiosis. In a -infected SCID mouse model, a 64-day-consecutive treatment with MMV390048 resulted in the clearance of parasites. Meanwhile, an atovaquone (ATO) resistant parasite line was isolated from the group treated with ATO plus azithromycin. A nonsynonymous variant in the Y272C of the gene was confirmed by sequencing. Likewise, MMV390048 showed potent inhibition against ATO-resistant parasites. These results provide evidence of PI4K as a viable drug target for the radical cure of babesiosis, which will contribute to designing new compounds that can eradicate parasites.
Topics: Mice; Humans; Animals; Babesia microti; Babesiosis; Mice, SCID; 1-Phosphatidylinositol 4-Kinase; Babesia; Atovaquone; Immunocompromised Host; Gastropoda
PubMed: 36452305
DOI: 10.3389/fcimb.2022.1048962 -
Data in Brief Dec 2022The dataset presented here is related to a previous research article titled "Mitochondrial Complex III in Larval Stage of as a Potential Chemotherapeutic Target and in...
The dataset presented here is related to a previous research article titled "Mitochondrial Complex III in Larval Stage of as a Potential Chemotherapeutic Target and in vivo Efficacy of Atovaquone Against Primary Hydatid Cysts"[1]. In this report, data were collected from aerobic and anaerobic culture assays of protoscoleces in the presence of three anti-echinococcal drug candidates (atovaquone, mefloquine, and 3-bromopyruvic acid). The data were analyzed for viability of the protoscoleces between day 0 and day 7 upon adding drug candidates. In aerobic condition, all drug candidates caused damage to the protoscoleces, as described previously [1], [2], [3], [4], [5], [6]. Mefloquine, alone as well as in combination with atovaquone, immediately eliminated the protoscoleces, whereas combination of atovaquone with 3-bromopyruvic acid did not show clear synergy. In anaerobic condition, mefloquine, alone as well as in combination with atovaquone, eliminated protoscoleces immediately. 3-Bromopyruvic acid showed stronger efficacy in anaerobic condition than in aerobic condition. Combination of atovaquone with 3-bromopyruvic acid eliminated the protoscoleces, indicating that synergy occurred only under anaerobic condition. The data clarified that combined use of the three drugs eliminated protoscoleces in both aerobic and anaerobic conditions, hence suggesting that these could inhibit aerobic and anaerobic respiration pathways of in vivo. The obtained data would be useful for the development of new drug dosing method for alveolar echinococcosis.
PubMed: 36426011
DOI: 10.1016/j.dib.2022.108707 -
CPT: Pharmacometrics & Systems... Jan 2023Chemoprophylactics are a vital tool in the fight against malaria. They can be used to protect populations at risk, such as children younger than the age of 5 in areas of...
Chemoprophylactics are a vital tool in the fight against malaria. They can be used to protect populations at risk, such as children younger than the age of 5 in areas of seasonal malaria transmission or pregnant women. Currently approved chemoprophylactics all present challenges. There are either concerns about unacceptable adverse effects such as neuropsychiatric sequalae (mefloquine), risks of hemolysis in patients with G6PD deficiency (8-aminoquinolines such as tafenoquine), or cost and daily dosing (atovaquone-proguanil). Therefore, there is a need to develop new chemoprophylactic agents to provide more affordable therapies with better compliance through improving properties such as pharmacokinetics to allow weekly, preferably monthly, dosing. Here we present a pharmacokinetic-pharmacodynamic (PKPD) model constructed using DSM265 (a dihydroorotate dehydrogenase inhibitor with activity against the liver schizonts of malaria, therefore, a prophylaxis candidate). The PKPD model mimics the parasite lifecycle by describing parasite dynamics and drug activity during the liver and blood stages. A major challenge is the estimation of model parameters, as only blood-stage parasites can be observed once they have reached a threshold. By combining qualitative and quantitative knowledge about the parasite from various sources, it has been shown that it is possible to infer information about liver-stage growth and its initial infection level. Furthermore, by integrating clinical data, the killing effect of the drug on liver- and blood-stage parasites can be included in the PKPD model, and a clinical outcome can be predicted. Despite multiple challenges, the presented model has the potential to help translation from preclinical to late development for new chemoprophylactic candidates.
Topics: Child; Humans; Female; Pregnancy; Antimalarials; Malaria; Glucosephosphate Dehydrogenase Deficiency; Enzyme Inhibitors; Liver
PubMed: 36412499
DOI: 10.1002/psp4.12875 -
Journal of Mass Spectrometry and... Nov 2022Atovaquone has traditionally been used as an antiparasitic and antifungal agent, but recent studies have shown its potential as an anticancer agent. The high variability...
BACKGROUND
Atovaquone has traditionally been used as an antiparasitic and antifungal agent, but recent studies have shown its potential as an anticancer agent. The high variability in atovaquone bioavailability highlights the need for therapeutic drug monitoring, especially in pediatric patients. The goal of our study was to develop and validate the performance of an assay to quantify atovaquone plasma concentrations collected from pediatric cancer patients using LC-MS/MS.
METHODS
Atovaquone was extracted from a 10 µL volume of K-EDTA human plasma using a solution consisting of ACN: EtOH: DMF (8:1:1 v:v:v), separated using reverse-phase chromatography, and detected using a SCIEX 5500 QTrap MS system. LC-MS/MS assay performance was evaluated for precision, accuracy, carryover, sensitivity, specificity, linearity, and interferences.
RESULTS
Atovaquone and its deuterated internal standard were analyzed using a gradient chromatographic method that had an overall cycle-time of 7.4 min per injection, and retention times of 4.3 min. Atovaquone was measured over a dynamic concentration range of 0.63 - 80 µM with a deviation within ≤ ± 5.1 % of the target value. Intra- and inter-assay precision were ≤ 2.7 % and ≤ 8.4 %, respectively. Dilutional, carryover, and interference studies were also within acceptable limits.
CONCLUSIONS
Our studies have shown that our LC-MS/MS-based method is both reliable and robust for the quantification of plasma atovaquone concentrations and can be used to determine the effective dose of atovaquone for pediatric patients treated for AML.
PubMed: 36388060
DOI: 10.1016/j.jmsacl.2022.09.004 -
BMC Medicine Nov 2022Individuals with a family history of colorectal cancer (CRC) are at a high risk of developing CRC. Preclinical studies suggest that the anti-malaria drug proguanil and...
BACKGROUND
Individuals with a family history of colorectal cancer (CRC) are at a high risk of developing CRC. Preclinical studies suggest that the anti-malaria drug proguanil and atovaquone might play a role in preventing CRC, but population-based evidence is still lacking.
METHODS
By accessing a couple of nationwide Swedish registers, we performed a cohort study to explore whether using proguanil and atovaquone might associate with a lower risk of CRC by adopting a new-user study design. Adults who have 1 or more first-degree relatives (parents or siblings) diagnosed with CRC were identified and linked with the Prescribed Drug Register to evaluate their administration history of proguanil and atovaquone. Survival analysis of the time to CRC diagnosis with Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).
RESULTS
A total of 16,817 incident proguanil/atovaquone users were identified and matched with 168,170 comparisons, who did not use proguanil/atovaquone, on the ratio of 1:10. We found a significant negative association between proguanil/atovaquone use and risk of CRC (adjusted HR, 0.76; 95% CI, 0.62-0.93). Test for trend showed significant dose- and duration-response correlations (P < 0.001). The association was more pronounced in CRC diagnosed at an advanced stage than at an early stage (adjusted HR, 0.69 vs.0.81).
CONCLUSIONS
This national-wide population-based cohort study showed that the use of proguanil and atovaquone was associated with a reduced risk of CRC among individuals with a family history of CRC.
Topics: Adult; Humans; Proguanil; Atovaquone; Cohort Studies; Drug Combinations; Antimalarials; Colorectal Neoplasms; Malaria, Falciparum
PubMed: 36357883
DOI: 10.1186/s12916-022-02643-3 -
The American Journal of Case Reports Nov 2022BACKGROUND On rare occasions, viral infections are known to also depress immune cell lines, further worsening clinical outcomes. We describe a patient who presented 3...
BACKGROUND On rare occasions, viral infections are known to also depress immune cell lines, further worsening clinical outcomes. We describe a patient who presented 3 weeks after recovery from mild COVID-19 disease with clinical features of an atypical pneumonia and was found to have a low CD4+ T-cell count. CASE REPORT An 82-year-old man with a past medical history of coronary artery disease, rheumatoid arthritis, gout, hypertension, and atrial fibrillation presented with a 1-week history of progressively worsening shortness of breath and cough. He was noted to have recovered from mild SARS-CoV-2 infection 3 weeks prior to his current presentation and had been at his baseline level of health following infection. A T cell subset panel was obtained, which revealed an absolute CD3 count of 92 (reference range 840-3060), absolute CD4 count of 52 (reference range 500-1400), absolute CD8 count of 37 (reference range 180-1170), and a normal CD4: CD8 ratio. He was subsequently started on atovaquone for pneumocystis jiroveci pneumonia prophylaxis. CONCLUSIONS This case highlights the need for a high index of suspicion for lymphocyte depletion in older patients with multiple comorbidities who present during or after SARS-CoV-2 infection with atypical symptoms that are suggestive of immunosuppression. In such instances, there should be a low threshold to start prophylactic therapy for possible opportunistic infections.
Topics: Male; Humans; Aged; Aged, 80 and over; COVID-19; SARS-CoV-2; T-Lymphocyte Subsets; Pneumonia, Pneumocystis; Cough
PubMed: 36318517
DOI: 10.12659/AJCR.937760 -
Frontiers in Pharmacology 2022Ulcerative colitis (UC) is a chronic relapsing disease featuring aberrant accumulation of neutrophils in colonic mucosa and the luminal space. Although significant...
Ulcerative colitis (UC) is a chronic relapsing disease featuring aberrant accumulation of neutrophils in colonic mucosa and the luminal space. Although significant advances in UC therapy have been made with the development of novel biologics and small molecules targeting immune responses, success of most current therapies is still limited, with significant safety concerns. Thus, there is a need to develop additional safe and effective therapies for the treatment of UC. Antimalarial drugs have been safely used for many years to resolve tissue inflammation and the associated pathologies. Atovaquone is a recent FDA-approved antimalarial drug that has shown anti-viral and tumor-suppressive properties however, its role in mucosal inflammation has not been evaluated. Using pre-clinical murine DSS-induced colitis model combined with complementary peritonitis and human neutrophil activation and chemotaxis assays we investigated functional and mechanistic impacts of atovaquone on disease resolution and neutrophil trafficking. We demonstrate that atovaquone promotes resolution of DSS-induced murine colitis by reducing neutrophil accumulation in the inflamed colonic mucosa. Mechanistically, we show that atovaquone suppressed induction of CD11b expression in neutrophils, reducing their polarization and migratory ability. Thus, our findings identify a new role of atovaquone in promoting resolution of mucosal inflammation, supporting the idea of potential repurposing of this FDA-approved drug as UC therapeutic.
PubMed: 36313299
DOI: 10.3389/fphar.2022.1011115 -
Frontiers in Pharmacology 2022An screen was performed to identify FDA approved drugs that inhibit SARS-CoV-2 main protease (M), followed by viral replication assays, and pharmacokinetic studies...
An screen was performed to identify FDA approved drugs that inhibit SARS-CoV-2 main protease (M), followed by viral replication assays, and pharmacokinetic studies in mice. These studies identified atovaquone as a promising candidate for inhibiting viral replication. A 2-center, randomized, double-blind, placebo-controlled trial was performed among patients hospitalized with COVID-19 infection. Enrolled patients were randomized 2:1 to atovaquone 1500 mg BID matched placebo. Patients received standard of care treatment including remdesivir, dexamethasone, or convalescent plasma as deemed necessary by the treating team. Saliva was collected at baseline and twice per day for up to 10 days for RNA extraction for SARS-CoV-2 viral load measurement by quantitative reverse-transcriptase PCR. The primary outcome was the between group difference in log-transformed viral load (copies/mL) using a generalized linear mixed-effect models of repeated measures from all samples. Of the 61 patients enrolled; 41 received atovaquone and 19 received placebo. Overall, the population was predominately male (63%) and Hispanic (70%), with a mean age of 51 years, enrolled a mean of 5 days from symptom onset. The log viral load was 5.25 copies/mL . 4.79 copies/mL at baseline in the atovaquone . placebo group. Change in viral load did not differ over time between the atovaquone plus standard of care arm the placebo plus standard of care arm. Pharmacokinetic (PK) studies of atovaquone plasma concentration demonstrated a wide variation in atovaquone levels, with an inverse correlation between BMI and atovaquone levels, (Rho -0.45, = 0.02). In post hoc analysis, an inverse correlation was observed between atovaquone levels and viral load (Rho -0.54, = 0.005). In this prospective, randomized, placebo-controlled trial, atovaquone did not demonstrate evidence of enhanced SARS-CoV-2 viral clearance compared with placebo. However, based on the observed inverse correlation between atovaquone levels and viral load, additional PK-guided studies may be warranted to examine the antiviral effect of atovaquone in COVID-19 patients.
PubMed: 36249792
DOI: 10.3389/fphar.2022.1020123