HLM chip - A microfluidic approach to study the mechanistic basis of cytochrome P450 inhibition using immobilized human liver microsomes.

Cytochrome P450 (CYP) system is a critical elimination route to most pharmaceuticals in human, but also prone to drug-drug interactions arising from the fact that concomitantly administered pharmaceuticals inhibit one another's CYP metabolism. The most severe form of CYP interactions is irreversible inhibition, which results in permanent inactivation of the critical CYP pathway and is only restored by de novo synthesis of new functional enzymes. In this study, we conceptualize a microfluidic approach to mechanistic CYP inhibition studies using human liver microsomes (HLMs) immobilized onto the walls of a polymer micropillar array. We evaluated the feasibility of these HLM chips for CYP inhibition studies by establishing the stability and the enzyme kinetics for a CYP2C9 model reaction under microfluidic flow and determining the half-maximal inhibitory concentrations (IC50) of three human CYP2C9 inhibitors (sulfaphenazole, tienilic acid, miconazole), including evaluation of their inhibition mechanisms and nonspecific microsomal binding on chip. Overall, the enzyme kinetics of CYP2C9 metabolism on the HLM chip (KM = 127 ± 55 µM) was shown to be similar to that of static HLM incubations (KM = 114 ± 14 µM) and the IC50 values toward CYP2C9 derived from the microfluidic assays (sulfaphenazole 0.38 ± 0.09 µM, tienilic acid 3.4 ± 0.6 µM, miconazole 0.54 ± 0.09 µM) correlated well with those determined using current standard IC50 shift assays. Most importantly, the HLM chip could distinguish between reversible (sulfaphenazole) and irreversible (tienilic acid) enzyme inhibitors in a single, automated experiment, indicating the great potential of the HLM chip to simplify current workflows used in mechanistic CYP inhibition studies. Furthermore, the results suggest that the HLM chip can also identify irreversible enzyme inhibitors, which are not necessarily resulting in a time-dependent inhibition (like suicide inhibitors), but whose inhibition mechanism is based on other kind of covalent or irreversible interaction with the CYP system. With our HLM chip approach, we could identify miconazole as such a compound that nonselectively inhibits the human CYP system with a prolonged, possibly irreversible impact in vitro, even if it is not a time-dependent inhibitor according to the IC50 shift assay.

Variations in prothrombin time-international normalized ratio caused by drug-drug interaction in patients receiving warfarin: A retrospective observational study.

OBJECTIVES: Drug-drug interactions between warfarin and cytochrome P450 (CYP) 2C9 inhibitors and inducers are well known. Few studies have clarified the clinical impact of CYP2C9 inhibitors and inducers on warfarin therapy. Here, we evaluated the clinical impact of CYP2C9-mediated interactions on the pharmacodynamics of warfarin. MATERIALS AND METHODS: This retrospective observational study enrolled patients who received warfarin between 2008 and 2020 at Mie University Hospital. We defined prothrombin time-international normalized ratio/daily warfarin dose (PT-INR/dose) as the primary outcome and conducted a multiple linear regression analysis to clarify the factors that affected the primary outcome. Additionally, we examined the clinical features of patients who received CYP2C9 inducers. RESULTS: Out of 1,393 patients, 17 (1.2%) received carbamazepine, rifampicin, phenobarbital, or phenytoin as CYP2C9 inducers. Multiple linear regression analysis indicated that age, body mass index (BMI), serum albumin (Alb), estimated glomerular filtration rate (eGFR), and CYP2C9 inducers were associated with PT-INR/dose. The multiple regression equation was as follows: PT-INR/dose = 1.590 + 0.004 × age - 0.020 × BMI - 0.141 × Alb - 0.001 × eGFR - 0.149 × (if concomitant use of CYP2C9 inducers) (adjusted coefficient of determination = 0.106, Akaike information criterion = 267.3, p < 0.001). In patients receiving CYP2C9 inducers, lower PT-INR/dose values were observed regardless of co-administered CYP2C9 inhibitors. CONCLUSION: In addition to age, BMI, Alb, and eGFR, concomitant use of CYP2C9 inducers should be considered when adjusting the warfarin dose and PT-INR.

Discovery of 5-methyl-1H-benzo[d]imidazole derivatives as novel P2X3 Receptor antagonists.

Drug discovery programs targeting P2X3 receptors (P2X3R), an extracellular adenosine 5'-triphosphate (ATP) gated cation channel family, have been actively investigated for several CNS-related diseases. The current unmet need in the field of P2X3R targeted drugs is to avoid a side effect, the loss of taste, that could be reduced by increase of the P2X3R selectivity vs P2X2/3R. In this study, 5-methyl-1H-benzo[d]imidazole derivatives were designed and synthesized from the analysis of key pharmacophores of current antagonists. In the structure-activity relationship study, the most potent compounds 17a-b was discovered as potent P2X3R antagonists with IC50 values of 145 and 206 nM, and selectivity index of 60 and 41, respectively. In addition, 17a-b showed the not-competitive antagonism, but poor binding score in the docking study at the known allosteric binding site of Gefapixant binding site, indicating that another allosteric binding site might be existing for the novel P2X3R antagonists.

Discovery of benzyloxyphenyl- and phenethylphenyl-imidazole derivatives as a new class of ante-drug type boosters.

Although cytochrome P450 3A4 (CYP3A4) inhibitors are used as boosters to increase drug absorption, the inhibition of CYP3A4 activity may affect the metabolism of other co-administered drugs. Therefore, we screened for and developed a new class of boosters to improve the oral availability of drugs. We identified benzyloxyphenyl imidazole and phenethylphenyl imidazole derivatives as new types of CYP3A4 inhibitors. Among the compounds synthesized, an ester 5c was found to inhibit CYP activity and the compound 5c was gradually converted to an inactive metabolite 5d under physiological conditions, indicating that the ester 5c may represent a novel ante-drug type booster.

Pharmacokinetic study on the interaction between succinic acid and irbesartan in rats and its potential mechanism.

CONTEXT: Succinic acid and irbesartan are commonly used drugs in cardiovascular disease treatment. The interaction might occur during their co-administration, which was still unclear. OBJECTIVE: To reveal the effect of succinic acid on the metabolism of irbesartan and its potential mechanism. MATERIALS AND METHODS: The Sprague-Dawley rats (n = 6) were treated with a single dose of 30 mg/kg irbesartan (control) or the co-administration with the pre-treatment of 200 mg/kg succinic acid for 7 d. The effect of succinic acid on the metabolic stability and the activity of CYP2C9 was evaluated in rat liver microsomes. RESULTS: Succinic acid increased the AUC (5328.71 ± 959.31 µg/L × h vs. 3340.23 ± 737.75 µg/L × h) and prolonged the half-life of irbesartan (from 12.79 ± 0.73 h to 20.59 ± 6.35 h). The Tmax (2.83 ± 0.75 h vs. 3.83 ± 1.10 h) and clearance rate (3.46 ± 1.13 L/h/kg vs. 6.91 ± 1.65 L/h/kg) of irbesartan was reduced by succinic acid. Consistently, succinic acid improved the metabolic stability (half-life from 23.32 ± 3.46 to 27.35 ± 2.15 min, intrinsic clearance rate from 59.43 ± 6.12 to 50.68 ± 5.64 µL/min/mg protein). Succinic acid was also found to inhibit the activity of CYP2C9 with the IC50 value of 13.87 µM. DISCUSSION AND CONCLUSIONS: Succinic acid increased the system exposure of irbesartan via inhibiting CYP2C9. The experiment design of this study also provides a reference for the further validation of this interaction in humans.

Ruxolitinib exposure in patients with acute and chronic graft versus host disease in routine clinical practice-a prospective single-center trial.

PURPOSE: Knowledge on Ruxolitinib exposure in patients with graft versus host disease (GvHD) is scarce. The purpose of this prospective study was to analyze Ruxolitinib concentrations of GvHD patients and to investigate effects of CYP3A4 and CYP2C9 inhibitors and other covariates as well as concentration-dependent effects. METHODS: 262 blood samples of 29 patients with acute or chronic GvHD who were administered Ruxolitinib during clinical routine were analyzed. A population pharmacokinetic model obtained from myelofibrosis patients was adapted to our population and was used to identify relevant pharmacokinetic properties and covariates on drug exposure. Relationships between Ruxolitinib exposure and adverse events were assessed. RESULTS: Median of individual mean trough serum concentrations was 39.9 ng/mL at 10 mg twice daily (IQR 27.1 ng/mL, range 5.6-99.8 ng/mL). Applying a population pharmacokinetic model revealed that concentrations in our cohort were significantly higher compared to myelofibrosis patients receiving the same daily dose (p < 0.001). Increased Ruxolitinib exposure was caused by a significant reduction in Ruxolitinib clearance by approximately 50%. Additional comedication with at least one strong CYP3A4 or CYP2C9 inhibitor led to a further reduction by 15% (p < 0.05). No other covariate affected pharmacokinetics significantly. Mean trough concentrations of patients requiring dose reduction related to adverse events were significantly elevated (p < 0.05). CONCLUSION: Ruxolitinib exposure is increased in GvHD patients in comparison to myelofibrosis patients due to reduced clearance and comedication with CYP3A4 or CYP2C9 inhibitors. Elevated Ruxolitinib trough concentrations might be a surrogate for toxicity.

Risk prediction of drug-drug interaction potential of phenytoin and miconazole topical formulations.

The drug-drug interaction (DDI) risk of phenytoin with several topical formulations of miconazole is still unclear. The present investigation conducted in vitro-in vivo extrapolation to predict the potential risks. Our data indicated that miconazole potently inhibited phenytoin hydroxylation in both pooled human liver microsomes (HLMs) and recombinant cytochrome P450 2C9 (CYP2C9) with the Ki values of 125 ± 7 nM and 30 ± 2 nM, respectively. Quantitative prediction of DDI risk suggests that, beside intravenous administration or swallowed tablet, combination of phenytoin and miconazole high dose oral gel or buccal tablet may also result in a clinically significant increase of phenytoin AUC (>53%) by the inhibition of miconazole against phenytoin hydroxylation, consequently a higher frequency of adverse events, while the coadministration of miconazole vaginal formulation and phenytoin will be safe.

Mechanistic study of bergamottin-induced inactivation of CYP2C9.

Bergamottin (BGM) is a major furanocoumarin constituent of grapefruit and is reported to have inhibitory effects on cytochrome P450 enzymes. This study investigated the chemical interactions between BGM and the enzyme CYP2C9. BGM exhibited time-, concentration-, and NADPH-dependent inhibition of CYP2C9. Co-incubation with diclofenac, a reversible inhibitor of CYP2C9, attenuated the time-dependent enzyme inhibition. Exhaustive dialysis did not restore enzyme activity post-inhibition. Glutathione (GSH) and catalase/superoxide dismutase failed to reverse BGM-induced CYP2C9 inactivation. A GSH trapping study suggested that BGM was metabolized to an epoxide and/or γ-ketoenal that may have been responsible for the enzyme inactivation. In conclusion, BGM can be characterized as a mechanism-based inactivator of CYP2C9 acting via the formation of an epoxide and/or γ-ketoenal.

Pogostone inhibits the activity of CYP3A4, 2C9, and 2E1 in vitro.

CONTEXT: Pogostone possesses various pharmacological activities, which makes it widely used in the clinic. Its effect on the activity of cytochrome P450 enzymes (CYP450s) could guide its clinical combination. OBJECTIVE: To investigate the effect of pogostone on the activity of human CYP450s. MATERIALS AND METHODS: The effect of pogostone on the activity of CYP450s was evaluated in human liver microsomes (HLMs) compared with blank HLMs (negative control) and specific inhibitors (positive control). The corresponding parameters were obtained with 0-100 µM pogostone and various concentrations of substrates. RESULTS: Pogostone was found to inhibit the activity of CYP3A4, 2C9, and 2E1 with the IC50 values of 11.41, 12.11, and 14.90 µM, respectively. The inhibition of CYP3A4 by pogostone was revealed to be performed in a non-competitive and time-dependent manner with the Ki value of 5.69 µM and the KI/Kinact value of 5.86/0.056/(µM/min). For the inhibition of CYP2C9 and 2E1, pogostone acted as a competitive inhibitor with the Ki value of 6.46 and 7.67 µM and was not affected by the incubation time. DISCUSSION AND CONCLUSIONS: The inhibitory effect of pogostone on the activity of CYP3A4, 2C9, and 2E1 has been disclosed in this study, implying the potential risk during the co-administration of pogostone and drugs metabolized by these CYP450s. The study design provides a reference for further in vivo investigations to validate the potential interaction.

The inhibition of CYP1A2, CYP2C9, and CYP2D6 by pterostilbene in human liver microsomes.

This study used human liver microsomes to assess pterostilbene's effect on the metabolic activity of cytochrome P450 (CYP) 1A2, CYP2C9, and CYP2D6. The metabolism of their substrates (phenacetin, tolbutamide, and dextromethorphan) was assayed by quantifying their relevant metabolites by HPLC. The IC50 value was used to express the strength of inhibition, and the value of a volume per dose index (VDI) was used to indicate the metabolic ability of the enzyme. In this study, pterostilbene inhibited CYP1A2, CYP2C9, and CYP2D6's metabolic activities in vitro. CYP2C9's activity was most significantly inhibited by pterostilbene; its IC50 value was 0.12±0.04 µM. The IC50 value of CYP1A2 and CYP2D6 was 56.3±10.4 µM and 62.33±11.4 µM, respectively. The finding that suggests that pterostilbene has the potential to interact with CYP2C9 substrates in vivo. These results warrant clinical studies to assess the in vivo significance of these interactions.

The optimization and characterization of functionalized sulfonamides derived from sulfaphenazole against Mycobacterium tuberculosis with reduced CYP 2C9 inhibition.

In this study, a series of sulfonamide compounds was designed and synthesized through the systematic optimization of the antibacterial agent sulfaphenazole for the treatment of Mycobacterium tuberculosis (M. tuberculosis). Preliminary results indicate that the 4-aminobenzenesulfonamide moiety plays a key role in maintaining antimycobacterial activity. Compounds 10c, 10d, 10f and 10i through the optimization on phenyl ring at the R2 site on the pyrazole displayed promising antimycobacterial activity paired with low cytotoxicity. In particular, compound 10d displayed good activity (MIC = 5.69 µg/mL) with low inhibition of CYP 2C9 (IC50 > 10 µM), consequently low potential risk of drug-drug interaction. These promising results provide new insight into the combination regimen using sulfonamide as one component for the treatment of M. tuberculosis.

Amentoflavone Induces Cell-cycle Arrest, Apoptosis, and Invasion Inhibition in Non-small Cell Lung Cancer Cells.

BACKGROUND/AIM: Amentoflavone, an effective compound derived from medicinal plants, has been shown to boost therapeutic efficacy of chemotherapy in non-small cell lung cancer (NSCLC). However, anti-NSCLC effect of amentoflavone is ambiguous. The major purpose of the present study was to verify the inhibitory effects of amentoflavone in NSCLC cells. MATERIALS AND METHODS: The effects of amentoflavone on growth and invasion of NSCLC CL-1-5-F4 cells were evaluated by cell viability assay, flow cytometry, colony formation assay, nuclear factor-kappa B (NF-κB) reporter gene assay, immunofluorescence staining, transwell invasion, and western blot assay. RESULTS: Amentoflavone effectively induced cell growth inhibition, G1 cell-cycle arrest, apoptosis, and suppression of invasion. Furthermore, amentoflavone not only triggered expression of p27, cleaved caspase-3, -8 also reduced NF-κB signaling, protein levels of matrix metalloproteinase (MMP)-2, -9, Cyclin-D1, and vascular endothelial growth factor (VEGF). CONCLUSION: Cell-cycle arrest, apoptosis induction, NF-κB signaling inhibition are associated with amentoflavone-inhibited growth and invasion of NSCLC cells.

Modulation of CYP3A4 and CYP2C9 activity by Bulbine natalensis and its constituents: An assessment of HDI risk of B. natalensis containing supplements.

BACKGROUND: Bulbine natalensis is an African-folk medicinal plant used as a dietary supplement for enhancing sexual function and muscle strength in males by presumably boosting testosterone levels, but no scientific information is available about the possible herb-drug interaction (HDI) risk when bulbine-containing supplements are concomitantly taken with prescription drugs. PURPOSE: This study was aimed to investigate the HDI potential of B. natalensis in terms of the pregnane X receptor (PXR)-mediated induction of major drug-metabolizing cytochrome P450 enzyme isoforms (i.e., CYP3A4 and CYP2C9) as well as inhibition of their catalytic activity. RESULTS: We found that a methanolic extract of B. natalensis activated PXR (EC50 6.2 ± 0.6 µg/ml) in HepG2 cells resulting in increased mRNA expression of CYP3A4 (2.40 ± 0.01 fold) and CYP2C9 (3.37 ± 0.3 fold) at 30 µg/ml which was reflected in increased activites of the two enzymes. Among the constituents of B. natalensis, knipholone was the most potent PXR activator (EC50 0.3 ± 0.1 µM) followed by bulbine-knipholone (EC50 2.0 ± 0.5 µM), and 6'-methylknipholone (EC50 4.0 ± 0.5 µM). Knipholone was also the most effective in increasing the expression of CYP3A4 (8.47 ± 2.5 fold) and CYP2C9 (2.64 ± 0.3 fold) at 10 µM. Docking studies further confirmed the unique structural features associated with knipholones for their superior inductive potentials in the activation of PXR compared to other anthraquinones. In a CYP inhibition assay, the methanolic extract as well as the anthraquinones strongly inhibited the catalytic activity of CYP2C9 while, inhibition of CYP3A4 was weak. CONCLUSIONS: These results suggest that consumption of B. natalensis may pose a potential risk for HDI if taken with conventional medications that are substrates of CYP3A4 and CYP2C9 and may contribute to unanticipated adverse reactions or therapeutic failures. Further studies are warranted to validate these findings and establish their clinical relevancy.

Succinic acid inhibits the activity of cytochrome P450 (CYP450) enzymes.

CONTEXT: Succinic acid, extracted from amber, is widely used in cardiovascular therapy. OBJECTIVE: The effect of succinic acid on the activity of cytochrome P450 (CYP450) enzymes was investigated in this study. MATERIALS AND METHODS: The effect of succinic acid (100 µM) on the activity of eight isoforms of CYP450 (i.e., 1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19 and 2C8) was investigated compared to the specific inhibitor and blank controls in pooled human liver microsomes in vitro. The inhibition of CYPs was fitted with competitive or non-competitive inhibition models and corresponding parameters were also obtained. RESULTS: Succinic acid exerted inhibitory effect on the activity of CYP3A4, 2D6, and 2C9 with the IC50 values of 12.82, 14.53, and 19.60 µM, respectively. Succinic acid inhibited the activity of CYP3A4 in a non-competitive manner with the Ki value of 6.18 µM, and inhibited CYP2D6 and 2C9 competitively with Ki values of 7.40 and 9.48 µM, respectively. Furthermore, the inhibition of CYP3A4 was found to be time-dependent with the KI/Kinact value of 6.52/0.051 min-1·µM-1. DISCUSSION AND CONCLUSIONS: Succinic acid showed in vitro inhibitory effects on the activity of CYP3A4, 2D6, and 2C9, which indicated the potential drug-drug interactions. Succinic acid should be carefully co-administrated with the drugs metabolized by CYP3A4, 2D6, and 2C9.

Assessment of Clinical Drug-Drug Interactions of Elagolix, a Gonadotropin-Releasing Hormone Receptor Antagonist.

Elagolix is an oral gonadotropin-releasing hormone receptor antagonist indicated for the management of endometriosis-associated pain and in combination with estradiol/norethindrone acetate indicated for the management of heavy menstrual bleeding associated with uterine leiomyomas (fibroids) in premenopausal women. Elagolix coadministered with estradiol/norethindrone acetate is in late-stage development for the management of heavy menstrual bleeding associated with uterine fibroids. Based on the in vitro profile of elagolix metabolism and disposition, 9 drug-drug interaction (DDI) studies evaluating the victim and perpetrator characteristics of elagolix were conducted in 144 healthy volunteers. As a victim of cytochrome P450 (CYPs) and transporter-mediated DDIs, elagolix area under the curve (AUC) increased by ∼2-fold following coadministration with ketoconazole and by ∼5- and ∼2-fold with single and multiple doses of rifampin, respectively. As a perpetrator, elagolix decreased midazolam AUC (90% confidence interval) by 54% (50%-59%) and increased digoxin AUC by 32% (23%-41%). Elagolix decreased rosuvastatin AUC by 40% (29%-50%). No clinically significant changes in exposure on coadministration with sertraline or fluconazole occurred. A elagolix 150-mg once-daily regimen should be limited to 6 months with strong CYP3A inhibitors and rifampin because of the potential increase in bone mineral density loss, as described in the drug label. A 200-mg twice-daily regimen is recommended for no more than 1 month with strong CYP3A inhibitors and not recommended with rifampin. Elagolix is contraindicated with strong organic anion transporter polypeptide B1 inhibitors (eg, cyclosporine and gemfibrozil). Consider increasing the doses of midazolam and rosuvastatin when coadministered with elagolix, and individualize therapy based on patient response. Clinical monitoring is recommended for P-glycoprotein substrates with a narrow therapeutic window (eg, digoxin). Dose adjustments are not required for sertraline, fluconazole, bupropion (or any CYP2B6 substrate), or elagolix when coadministered.

Identification of a novel orally bioavailable NLRP3 inflammasome inhibitor.

NLRP3 inflammasome mediated release of interleukin-1ß (IL-1ß) has been implicated in various diseases, including COVID-19. In this study, rationally designed alkenyl sulfonylurea derivatives were identified as novel, potent and orally bioavailable NLRP3 inhibitors. Compound 7 was found to be potent (IL-1ß IC50 = 35 nM; IL-18 IC50 = 33 nM) and selective NLRP3 inflammasome inhibitor with excellent pharmacokinetic profile having oral bioavailability of 99% in mice.

Inhibition of CYP2C9 by natural products: insight into the potential risk of herb-drug interactions.

Due to the rapidly increasing global interest in the use of herbs, phytomedicines and other natural products as medical or complementary remedies, concerns about the clinical medication safety have drawn much attention worldwide. Particularly, many natural ingredients exhibit inhibitory effects on cytochrome P450 (CYP) enzymes, which are the most important Phase I metabolism enzymes in liver. CYP2C9 is one of the most abundant CYP enzymes and responsible for the metabolism of over 15% clinical drugs, including oral sulfonylurea hypoglycemics, nonsteroidal anti-inflammatory agents, selective cyclooxygenase-2 inhibitors, antiepileptics, angiotensin II receptor inhibitors and anticoagulants. Diclofenac (4'-hydroxylase) and tolbutamide (methylhydroxylation) are widely used as probe substrates for CYP2C9. To date, numerous natural products have been reported to have the capabilities of inhibiting the catalytic activity of CYP2C9 and further influencing the pharmacokinetic and pharmacodynamic behaviors of drugs that are mainly metabolized by CYP2C9, leading to potential herb-drug interactions. Moreover, some fatal adverse interactions may occur for drugs with a narrow therapeutic window when they are coadministered with a CYP2C9 inhibitor, especially irreversible inactivators. For the purpose of better understanding the interactions of natural products with CYP2C9, we comprehensively reviewed the characteristics of CYP2C9, the natural ingredients that inhibit CYP2C9, the related research approaches and strategies, the types of inhibition and the underlying mechanisms.

Mother-to-Child HIV Transmission With In Utero Dolutegravir vs. Efavirenz in Botswana.

BACKGROUND: A large-scale evaluation of mother-to-child transmission (MTCT) with dolutegravir (DTG)-based antiretroviral treatment (ART) has not been conducted previously. SETTING: Botswana was the first African country to change from efavirenz (EFV)/tenofovir (TDF)/emtricitabine (FTC) to DTG/TDF/FTC first-line ART. METHODS: From April 2015 to July 2018, the Early Infant Treatment Study offered HIV DNA testing at <96 hours of life. Maternal ART regimen was available for screened infants who could be linked to the separate Tsepamo surveillance study database. We evaluated characteristics of HIV-positive infants, and compared MTCT rates by ART regimen for linked infants. RESULTS: Of 10,622 HIV-exposed infants screened, 42 (0.40%) were HIV-positive. In total, 5064 screened infants could be linked to the surveillance database, including 1235 (24.4%) exposed to DTG/TDF/FTC and 2411 (47.6%) exposed to EFV/TDF/FTC. MTCT was rare when either regimen was started before conception: 0/213 [0.00%, 95% confidence interval (CI): 0.00% to 1.72%] on DTG, 1/1497 (0.07%, 95% CI: 0.00% to 0.37%) on EFV. MTCT was similar for women starting each ART regimen in pregnancy: 8/999 (0.80%, 95% CI: 0.35% to 1.57%) for DTG and 8/883 (0.91%, 95% CI: 0.39% to 1.78%) for EFV (risk difference 0.11%, 95% CI: -0.79% to 1.06%). Most MTCT events (4/8 with DTG, 6/9 with EFV) occurred when ART was started <90 days before delivery. Infants exposed to DTG in utero had lower baseline HIV RNA compared with other HIV-infected infants. CONCLUSION: In utero MTCT in Botswana remains rare in the DTG era. No significant MTCT differences were observed between DTG/TDF/FTC and EFV/TDF/FTC. Risk was highest for both groups when ART was started in the third trimester.

Large-scale evaluation of cytochrome P450 2C9 mediated drug interaction potential with machine learning-based consensus modeling.

Cytochrome P450 (CYP) enzymes play an important role in the metabolism of xenobiotics. Since they are connected to drug interactions, screening for potential inhibitors is of utmost importance in drug discovery settings. Our study provides an extensive classification model for P450-drug interactions with one of the most prominent members, the 2C9 isoenzyme. Our model involved the largest set of 45,000 molecules ever used for developing prediction models. The models are based on three different types of descriptors, (a) typical one, two and three dimensional molecular descriptors, (b) chemical and pharmacophore fingerprints and (c) interaction fingerprints with docking scores. Two machine learning algorithms, the boosted tree and the multilayer feedforward of resilient backpropagation network were used and compared based on their performances. The models were validated both internally and using external validation sets. The results showed that the consensus voting technique with custom probability thresholds could provide promising results even in large-scale cases without any restrictions on the applicability domain. Our best model was capable to predict the 2C9 inhibitory activity with the area under the receiver operating characteristic curve (AUC) of 0.85 and 0.84 for the internal and the external test sets, respectively. The chemical space covered with the largest available dataset has reached its limit encompassing publicly available bioactivity data for the 2C9 isoenzyme.

Amentoflavone induces cell cycle arrest, apoptosis, and autophagy in BV-2 cells.

Previous studies have shown that amentoflavone (AF) elicits anti-inflammatory and neuroprotective effects. To further investigate the effects of AF on the microglia cell line BV-2, proteomic analysis was performed to screen potential key regulators. The top 5 canonical pathways associated with AF treatment were EIF2 signaling, regulation of eIF4 and p70s6k signaling, mTOR signaling, protein ubiquitination pathway and phagosome maturation. The top up-regulated genes were DOCK2, SEC23A, ME1, UGGT1 and STOM, while the most down-regulated molecules were IGF2R, ATP5O, DDX47, WBP11 and IKBIP. AF significantly decreased BV-2 cell proliferation. It induced cell cycle arrest at G2/M, increased CDK2, p27Kip1 and p53/p-p53, and decreased CDK1/CDC2 and cyclin B1. Cell apoptosis was induced, with increased levels of BAX, c-caspase-3 and c-caspase-9, and decreased levels of BCL-XL. Increased level of autophagosome induced by AF was observed, and increased Beclin-1 and decreased phosphorylation of PI3K and Erk1 were found as well. In conclusion, AF induces cell cycle arrest at G2/M, promotes apoptosis and autophagy in BV-2 cells, which may account for the anti-inflammatory effect of AF in epilepsy.