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JPhys energy 5(2), 021501 (2023). doi:10.1088/2515-7655/acaa57, Published by IOP Publishing, Bristol

Introduction Dosing recommendations for paliperidone long-acting injectable antipsychotic (LAIA) do not include oral antipsychotic (OAP) overlap; however, OAPs are often given concurrently despite limited evidence describing both the risks and benefits of this practice. Methods A retrospective chart review was conducted in patients initiated on paliperidone palmitate (PP) during a psychiatric hospitalization to compare patients who received OAP overlap versus those who did not. The primary outcome is the proportion of patients who receive prescription claims for benztropine, a medication commonly prescribed for extrapyramidal symptoms, at the time of LAIA discontinuation and 6 months postdischarge. Secondary outcomes include prescription claims for beta blockers and diphenhydramine, number of psychiatric emergency visits and hospitalizations, length of stay of the index hospitalization, frequency of LAIA discontinuation and the time to LAIA discontinuation. Results There is a significant difference in the proportion of benztropine prescription claims in the OAP overlap group versus the no-overlap group at the time of LAIA discontinuation (30% vs 0%, P = .046) but not at 6 months postdischarge. There are also significant differences in the number of psychiatric emergency visits (0.7 vs 0.1, P = .02) and psychiatric hospitalizations (0.6 vs 0.1, P = .029) at the time of LAIA discontinuation. No other differences are observed in defined secondary outcomes. Discussion Patients who receive OAP overlap while receiving PP receive more benztropine and have more psychiatric emergency visits and hospitalizations than those treated without OAP. Larger studies with better control for confounding variables are needed to confirm these results.

Cellular senescence is a stress response characterised by a permanent cell cycle arrest and a proinflammatory secretome. In addition to its tumour suppressor role, senescence is involved in ageing and promotes many disease processes such as cancer, type 2 diabetes, osteoarthritis, and SARS-CoV-2 infection. There is a growing interest in therapies based on targeted elimination of senescent cells, yet so far only a few such senolytics are known, partly due to the poor grasp of the molecular mechanisms that control the senescence survival programme. Here we report a highly effective machine learning pipeline for the discovery of senolytic compounds. Using solely published data, we trained machine learning algorithms to classify compounds according to their senolytic action. Models were trained on as few as 58 known senolytics against a background of FDA-approved compounds or in late-stage clinical development (2,523 in total). We computationally screened various chemical libraries and singled out top candidates for validation in human lung fibroblasts (IMR90) and lung adenocarcinoma (A549) cell lines. This led to the discovery of three novel senolytics: ginkgetin, oleandrin and periplocin, with potency comparable to current senolytics and a several hundred-fold reduction in experimental screening costs. Our work demonstrates that machine learning can take maximum advantage of existing drug screening data, paving the way for new open science approaches to drug discovery for senescence-associated diseases.

ObjectivesDolutegravir has replaced efavirenz as first-line treatment in universal HIV guidelines. We sought to ascertain the contributory effect of SNPs in four key genes linked to dolutegravir disposition (UGT1A1, ABCG2, CYP3A and NR1I2) on plasma dolutegravir pharmacokinetics.MethodsPaired pharmacogenetic/pharmacokinetic data from 93 subjects were analysed for association using multivariate linear regression.ResultsCo-occurring UGT1*28 and NR1I2 c.63396C>T homozygosity was associated with a 79% increase in AUC0–24 (P = 0.001; 27% if analysed individually), whilst combined ABCG2 c.421C>A and NR1I2 c.63396C>T variants were associated with a 43% increase in Cmax (P = 0.002) and a 39% increase in AUC0–24 (P = 0.002). When analysed individually, homozygosity for the NR1I2 c.63396C>T variant alleles was associated with a 28% increase in Cmax (P = 0.033) and homozygosity for the ABCG2 c.421C>A variant alleles was associated with a 28% increase in Cmax (P = 0.047). The UGT1A1*28 (rs8175347) poor metabolizer status (*28/*28; *28/*37; *37/*37) was individually associated with a 27% increase in AUC0–24 (P = 0.020). The combination of UGT1A1*28 poor metabolizer and UGT1A1*6 intermediate metabolizer statuses correlated with a 43% increase in AUC0–24 (P = 0.023).ConclusionsThis study showed a pharmacogenetic association between dolutegravir pharmacokinetics and variants in the ABCG2, UGT1A1 and NR1I2 genes, particularly when combined. Further research is warranted to confirm these associations in population-specific studies and to investigate their putative relationship with dolutegravir pharmacodynamics.

S-acylation, also known as palmitoylation, is the most abundant form of protein lipidation in humans. This reversible posttranslational modification, which targets thousands of proteins, is catalyzed by 23 members of the DHHC family of integral membrane enzymes. DHHC enzymes use fatty acyl-CoA as the ubiquitous fatty acyl donor and become autoacylated at a catalytic cysteine; this intermediate subsequently transfers the fatty acyl group to a cysteine in the target protein. Protein S-acylation intersects with almost all areas of human physiology, and several DHHC enzymes are considered as possible therapeutic targets against diseases such as cancer. These efforts would greatly benefit from a detailed understanding of the molecular basis for this crucial enzymatic reaction. Here, we combine X-ray crystallography with all-atom molecular dynamics simulations to elucidate the structure of the precatalytic complex of human DHHC20 in complex with palmitoyl CoA. The resulting structure reveals that the fatty acyl chain inserts into a hydrophobic pocket within the transmembrane spanning region of the protein, whereas the CoA headgroup is recognized by the cytosolic domain through polar and ionic interactions. Biochemical experiments corroborate the predictions from our structural model. We show, using both computational and experimental analyses, that palmitoyl CoA acts as a bivalent ligand where the interaction of the DHHC enzyme with both the fatty acyl chain and the CoA headgroup is important for catalytic chemistry to proceed. This bivalency explains how, in the presence of high concentrations of free CoA under physiological conditions, DHHC enzymes can efficiently use palmitoyl CoA as a substrate for autoacylation.

S-acylation, also known as palmitoylation, is the most widely prevalent form of protein lipidation, whereby long-chain fatty acids get attached to cysteine residues facing the cytosol. In humans, 23 members of the zDHHC family of integral membrane enzymes catalyze this modification. S-acylation is critical for the life cycle of many enveloped viruses. The Spike protein of SARS-CoV-2, the causative agent of COVID-19, has the most cysteine-rich cytoplasmic tail among known human pathogens in the closely related family of β-coronaviruses; however, it is unclear which of the cytoplasmic cysteines are S-acylated, and what the impact of this modification is on viral infectivity. Here we identify specific cysteine clusters in the Spike protein of SARS-CoV-2 that are targets of S-acylation. Interestingly, when we investigated the effect of the cysteine clusters using pseudotyped virus, mutation of the same three clusters of cysteines severely compromised viral infectivity. We developed a library of expression constructs of human zDHHC enzymes and used them to identify zDHHC enzymes that can S-acylate SARS-CoV-2 Spike protein. Finally, we reconstituted S-acylation of SARS-CoV-2 Spike protein in vitro using purified zDHHC enzymes. We observe a striking heterogeneity in the S-acylation status of the different cysteines in our in cellulo experiments, which, remarkably, was recapitulated by the in vitro assay. Altogether, these results bolster our understanding of a poorly understood posttranslational modification integral to the SARS-CoV-2 Spike protein. This study opens up avenues for further mechanistic dissection and lays the groundwork toward developing future strategies that could aid in the identification of targeted small-molecule modulators.

Background and objectives: Access to safe and reliable contraception in the context of ARVs is essential. This study aimed to investigate the steady-state pharmacokinetics (PK) of ethinylestradiol/levonorgestrel (EE/LNG) 30/150 μg (Microgynon®) and atazanavir/cobicistat (ATV/COBI) 300/150 mg (Evotaz®), co-administered in HIV negative female volunteers, and assess its safety and tolerability. Methods: This phase 1, open label, 57-day, cross over, PK study randomized participants to one of two groups: (i) group 1 received EE/LNG alone on days 1-21, EE/LNG (21 days) + ATV/COBI (14 days) in the co-administration phase (days 22-42) and ATV/COBI alone on days 43-56; (ii) group 2 followed the same sequence but started with ATV/COBI and concluding with EE/LNG. Each group underwent intensive PK sampling on days 14, 35, and 56. EE/LNG and ATV/COBI concentrations were measured using validated LC-MS/MS methods. Results: Of 14 healthy female volunteers screened, 11 attended baseline and six completed all PK phases (five withdrew secondary to side effects). Paired data were available for analysis in six subjects for EE/LNG and eight for ATV/COBI. Geometric mean ratios (GMR, with versus without ATV/COBI) and 90% confidence intervals (CI) for LNG Cmax, AUC0-24, C24 were 0.83 (0.68-1.02), 0.92 (0.71-1.18), 1.01 (0.73-1.38). GMR and 90% CI for EE Cmax, AUC0-24, C24 were 1.05 (0.92-1.19), 1.01 (0.83-1.22), 0.75 (0.60-0.93). No grade 3 or 4 adverse events or laboratory abnormalities were observed in the women who completed the study. Conclusions: Our findings showed no significant changes in LNG concentrations and a 25% decrease in EE C24 when EE/LNG was co-administered with ATV/COBI.

Multiple imputation is a well-established general technique for analyzing data with missing values. A convenient way to implement multiple imputation is sequential regression multiple imputation (SRMI), also called chained equations multiple imputation. In this approach, we impute missing values using regression models for each variable, conditional on the other variables in the data. This approach, however, assumes that the missingness mechanism is missing at random, and it is not well-justified under not-at-random missingness without additional modification. In this paper, we describe how we can generalize the SRMI imputation procedure to handle not-at-random missingness (MNAR) in the setting where missingness may depend on other variables that are also missing. We provide algebraic justification for several generalizations of standard SRMI using Taylor series and other approximations of the target imputation distribution under MNAR. Resulting regression model approximations include indicators for missingness, interactions, or other functions of the MNAR missingness model and observed data. In a simulation study, we demonstrate that the proposed SRMI modifications result in reduced bias in the final analysis compared to standard SRMI, with an approximation strategy involving inclusion of an offset in the imputation model performing the best overall. The method is illustrated in a breast cancer study, where the goal is to estimate the prevalence of a specific genetic pathogenic variant., See also: Supplemental Material

Neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers are among the most commonly used lasers with a wide variety of applications from biomedicine to manufacturing. The ubiquity of these lasers increases the likelihood of accidental ocular injury resulting in permanent visual impairment. We performed dosimetry studies to determine retinal damage thresholds and hemorrhagic lesions in the porcine eye with Qswitched Nd:YAG lasers. The Yucatan miniature pig model exhibited similarities in ocular anatomy to human eyes. The Nd:YAG laser, tuned to 1064 nm with a pulse width of seven nanoseconds, delivered laser energy to the retina. Retinal imaging modalities including fundus photography, real-time video, confocal scanning laser ophthalmoscopy (cSLO), and spectral domain optical coherence tomography (SD-OCT) provided visualization of retinal morphology at multiple time points. Retinal damage thresholds were grouped into three categories: minimum visible lesion (MVL), contained hemorrhagic lesion (CHL), and vitreal hemorrhagic lesion (VHL). Probit analysis determined the effective dose for 50% probability of damage (ED50) for each lesion category. The threshold to produce a MVL was 0.193 mJ based on 24-hour assessments of the retina. The one-hour hemorrhagic lesion thresholds were 0.408 mJ and 1.52 mJ for CHL and VHL, respectively

Background We investigated the pharmacokinetics (PK) of atazanavir/cobicistat and darunavir/cobicistat once daily over 72 h following drug intake cessation in plasma, saliva and urine. Methods Healthy volunteers received a fixed-dose combination of 300/150 mg of atazanavir/cobicistat once daily for 10 days, followed by a 10 day washout period and then a fixed-dose combination of 800/150 mg of darunavir/cobicistat once daily for 10 days. Full PK profiles were assessed for each phase for 72 h following day 10 and parameters determined to the last measurable concentration in plasma, saliva and urine by non-compartmental methods. Results Sixteen subjects completed the study. Geometric mean (GM) terminal elimination half-life values to 72 h of atazanavir and darunavir were 6.77 and 6.35 h, respectively. All subjects had atazanavir concentrations above the suggested minimum effective concentration of 150 ng/mL 24 h post-dose and 14/16 subjects had concentrations higher than this target at 30 h post-dose (GM of 759 and 407 ng/mL, respectively). Thirteen out of 16 subjects had darunavir concentrations higher than the target of 550 ng/mL at 24 h post-dose and 5/16 subjects had concentrations higher than the target at 30 h post-dose (GM of 1033 and 382 ng/mL, respectively). Cobicistat half-life to 72 h was 4.21 h with atazanavir and 3.62 h with darunavir. GM values 24 h after the observed dose ( C 24 ) for atazanavir and darunavir were 141 and 43 ng/mL, respectively, in saliva and 24857 and 11878 ng/mL, respectively, in urine. Concentration decay in saliva/urine mirrored plasma concentrations for both drugs. Conclusions Different concentration decay patterns were seen for atazanavir and darunavir, which may be partially explained by cobicistat half-life (longer with atazanavir than darunavir). For the first time, we also measured drug PK forgiveness in saliva and urine, which represent easier markers of adherence.

During the late phase of the HIV-1 replication cycle, the viral Gag polyproteins are targeted to the plasma membrane for assembly. The Gag-membrane interaction is mediated by binding of Gag's N-terminal myristoylated matrix (MA) domain to phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). The viral envelope (Env) glycoprotein is then recruited to the assembly sites and incorporated into budding particles. Evidence suggests that Env incorporation is mediated by interactions between Gag's MA domain and the cytoplasmic tail of the gp41 subunit of Env (gp41CT). MA trimerization appears to be an obligatory step for this interaction. Insufficient production of a recombinant MA trimer and unavailability of a biologically relevant membrane system have been barriers to detailed structural and biophysical characterization of the putative MA-gp41CT-membrane interactions. Here, we engineered a stable recombinant HIV-1 MA trimer construct by fusing a foldon domain (FD) of phage T4 fibritin to the MA C terminus. Results from NMR experiments confirmed that the FD attachment does not adversely alter the MA structure. Employing hydrogen-deuterium exchange MS, we identified an MA-MA interface in the MA trimer that is implicated in Gag assembly and Env incorporation. Utilizing lipid nanodiscs as a membrane mimetic, we show that the MA trimer binds to membranes 30-fold tighter than does the MA monomer and that incorporation of PI(4,5)P2 and phosphatidylserine enhances the binding of MA to nanodiscs. These findings advance our understanding of a fundamental mechanism in HIV-1 assembly and provide a template for investigating the interaction of MA with gp41CT. This work was supported by National Institutes of Health Grants 5R01GM117837 and 9R01AI150901 (to J.S.S.) Sí