Rapid quantitative detection system for measles virus-neutralizing antibodies using HiBiT-tagged virus-like particles.

Immunological testing to detect neutralizing antibodies (NAbs) is important in measles (MV) infection control. Currently, the plaque reduction neutralization test is the only credible method for measuring actual virus NAbs; however, its feasibility is hampered by drawbacks, such as long turnaround times, low throughput, and the need for laboratory biosafety equipment. To solve these problems, we developed a simple and rapid MV-NAb detection system using lentivirus-based virus-like particles incorporated with the NanoLuc fragment peptide HiBiT comprising the MV fusion protein and hemagglutinin on their exterior surface. Overall, this simple, safe, and rapid method could be used to detect MV NAbs.

Generation of a photocontrollable recombinant bovine parainfluenza virus type 3.

Bovine parainfluenza virus type 3 (BPIV3) is a promising vaccine vector against various respiratory virus infections, including the human PIV3, respiratory syncytial virus, and severe acute respiratory syndrome-coronavirus 2 infections. In this study, we combined the Magnet system and reverse genetic approach to generate photocontrollable BPIV3. An optically controllable Magnet gene was inserted into the H2 region of the BPIV3 large protein gene, which encodes an RNA-dependent RNA polymerase. The generated photocontrollable BPIV3 grew in specific regions of the cell sheet only when illuminated with blue light, suggesting that spatiotemporal control can aid in safe clinical applications of BPIV3.

Structure of a paramyxovirus polymerase complex reveals a unique methyltransferase-CTD conformation.

Paramyxoviruses are enveloped, nonsegmented, negative-strand RNA viruses that cause a wide spectrum of human and animal diseases. The viral genome, packaged by the nucleoprotein (N), serves as a template for the polymerase complex, composed of the large protein (L) and the homo-tetrameric phosphoprotein (P). The ∼250-kDa L possesses all enzymatic activities necessary for its function but requires P in vivo. Structural information is available for individual P domains from different paramyxoviruses, but how P interacts with L and how that affects the activity of L is largely unknown due to the lack of high-resolution structures of this complex in this viral family. In this study we determined the structure of the L-P complex from parainfluenza virus 5 (PIV5) at 4.3-Šresolution using cryoelectron microscopy, as well as the oligomerization domain (OD) of P at 1.4-Šresolution using X-ray crystallography. P-OD associates with the RNA-dependent RNA polymerase domain of L and protrudes away from it, while the X domain of one chain of P is bound near the L nucleotide entry site. The methyltransferase (MTase) domain and the C-terminal domain (CTD) of L adopt a unique conformation, positioning the MTase active site immediately above the poly-ribonucleotidyltransferase domain and near the likely exit site for the product RNA 5' end. Our study reveals a potential mechanism that mononegavirus polymerases may employ to switch between transcription and genome replication. This knowledge will assist in the design and development of antivirals against paramyxoviruses.

Naltrexone Transport by a Proton-Coupled Organic Cation Antiporter in hCMEC/D3 Cells, an in Vitro Human Blood-Brain Barrier Model.

Naltrexone is a mu-opioid receptor antagonist used in the treatment of opioid and alcohol dependence. The blood-brain barrier (BBB) transport characteristics of naltrexone was investigated by means of hCMEC/D3 cells, a human immortalized brain capillary endothelial cell line. In hCMEC/D3 cells, naltrexone is taken up in a concentration-dependent manner. Furthermore, naltrexone uptake significantly decreased in the presence of H+/organic cation (OC) antiporter substrates, during the little alteration exhibited by substrates of well-identified OC transporters classified into SLC22A family. Although naltrexone uptake by hCMEC/D3 cells was partially affected by changes of ionic conditions, it was markedly decreased in the presence of the metabolic inhibitor sodium azide. Furthermore, when treated by ammonium chloride, naltrexone uptake by hCMEC/D3 cells was altered by intracellular acidification and alkalization, suggesting the involvement of oppositely directed proton gradient in naltrexone transport across the BBB. The results obtained in the present in vitro study suggest the active transport of naltrexone from blood to the brain across the BBB by the H+/OC antiporter.

Possible Involvement of Muscarinic Receptor Blockade in Mirabegron Therapy for Patients with Overactive Bladder.

The selective ß 3-adrenoceptor agonist mirabegron, an established alternative to antimuscarinic therapy for patients with overactive bladder, induces additional effects against receptors, transporters, and hepatic enzymes. The present study aimed to elucidate the effects of mirabegron on muscarinic receptors in the rat bladder using radioligand binding and functional assays. Mirabegron (0.1-100 µM) inhibited specific [N-methyl-3H]scopolamine methyl chloride binding in the bladder and other tissues of rats in a concentration-dependent manner. Binding affinity in the bladder was similar to that in the heart and significantly higher than those in the submaxillary gland and brain. Mirabegron induced the concentration-dependent relaxation of carbachol-induced contractions in the rat isolated bladder. Further analyses using a two-site model revealed that the relative quantities of high- and low-affinity components for mirabegron were 44.5% and 55.5%, respectively. Respective pEC50 values were 7.06 and 4.97. Based on the receptor binding affinity and pharmacokinetics of mirabegron, muscarinic receptor occupancy in the human bladder for 24 hours after the administration of a single oral dose of 50 mg mirabegron was 37%-76%. The present results demonstrate for the first time that mirabegron may relax the detrusor smooth muscle not only by ß 3-adrenoceptor activation but also muscarinic receptor blockade. SIGNIFICANCE STATEMENT: Mirabegron, the first selective ß 3-adrenoceptor agonist, represents an alternative to antimuscarinic agents for management of overactive bladder (OAB). The present study aimed to clarify whether mirabegron directly binds to muscarinic receptors and affects cholinergic agonist-induced contractions in rat urinary bladder and to predict muscarinic receptor occupancy in human bladder after oral administration of mirabegron. The results demonstrated that mirabegron therapy for patients with OAB may be due not only to ß 3-adrenoceptor activation but also muscarinic receptor blockade.

Muscarinic receptor binding activity in rat tissues by vibegron and prediction of its receptor occupancy levels in the human bladder.

OBJECTIVES: To examine the effects of vibegron, a selective ß3 -adrenoceptor agonist, used to treat overactive bladder, on muscarinic receptors in the rat bladder, and to predict the occupancy levels of muscarinic receptors by vibegron in the bladders of humans orally administered a clinical dose. METHODS: Muscarinic receptors in the rat bladder and other tissues were examined by a radioligand binding assay using [N-methyl-3 H]scopolamine chloride. The occupancy levels of muscarinic receptors by vibegron in bladders of humans after its oral administration were predicted from the estimation of unbound concentrations in human plasma and urine in the literature. RESULTS: Vibegron (0.1-100 µmol/L) inhibited specific [N-methyl-3 H]scopolamine chloride binding in the bladder and other tissues of rats in a concentration-dependent manner. The 50% inhibitory concentration value of vibegron in the bladder was approximately twofold higher than that in the heart, and approximately 315- and 3.5-fold lower than those in the submaxillary gland and brain, respectively. Therefore, the binding affinity of vibegron for muscarinic receptors was higher in the heart and bladder than in the submaxillary gland and brain. By using the rat bladder receptor binding affinity, occupancy levels of muscarinic receptors in the human bladder were predicted to be 51-91% until 24 h after its oral administration at 50 mg of vibegron. CONCLUSIONS: This is the first study to suggest that vibegron binds to muscarinic receptors in the rat bladder and other tissues, with a potentially higher affinity for the M2 subtype than the M1 and M3 subtypes. These results might be clinically relevant for pharmacotherapy with vibegron for overactive bladder.

An educational intervention improved knowledge of dietary supplements in college students.

BACKGROUND: We have previously reported on the prevalence of dietary supplements among college students; it was deduced that their intake of supplements increased according to their grade (i.e., 13.1% in the first grade to 20.5% in the sixth grade). We also reported that some students had experienced adverse events in Japan due to their intake of these supplements. However, awareness of dietary supplements among college students remains limited, even among pharmaceutical students. Being appropriately educated about them is important for pharmaceutical students, both for themselves as well as for their future careers as pharmacists. METHODS: We conducted a lecture-based educational intervention about dietary supplements on 328 college students in Japan-184 from pharmaceutical science and 144 from environmental science or food and life science disciplines. The purpose of this study was to evaluate the effects of an educational intervention on college students' understanding of dietary supplements. The intervention involved a lecture that covered the quality of dietary supplements, how they differed from drugs, and a summary of their adverse events. The lecture was evaluated using a 14-question questionnaire. We then compared the pre- and post-intervention responses to the same questionnaire using a Wilcoxon signed-rank test. The questions were assessed using a Likert scale that ranged from "strongly agree" to "strongly disagree"; the latter being the preferred answer. RESULTS: Before the intervention had taken place, the students' understanding of dietary supplements was shown to be deficient. Conversely, post-intervention, their knowledge levels had significantly improved, especially concerning agreement on whether "Dietary supplements are safe because they are just food items". Pre-intervention, 2.7% strongly agreed and 37.5% agreed; post-intervention, 1.2% strongly agreed and 15.6% agreed. On whether "Dietary supplements made from natural ingredients or herbs are safe", at the pre-intervention stage 2.8% strongly agreed and 44.0% agreed and post-intervention, 2.2% strongly agreed and 16.9% agreed. On whether "Dietary supplements made from food items are safe", 4.0% strongly agreed and 43.6% agreed pre-intervention and 0.9% strongly agreed and 16.6% agreed post-intervention. Despite there being a greater number of pharmaceutical students who had a correct understanding of dietary supplements before the intervention, these students still showed improvement after the lecture. CONCLUSION: An intervention in the form of a single educational lecture has the capacity to improve college students' understanding of dietary supplements. It is important for pharmacists to be appropriately educated about dietary supplements when they consult with patients. We will evaluate the long-term effects of the intervention on the alumni (pharmacists) in a subsequent study.

Prostaglandin Transporter OATP2A1/SLCO2A1 Is Essential for Body Temperature Regulation during Fever.

Prostaglandin E2 (PGE2) in the hypothalamus is a principal mediator of the febrile response. However, the role of organic anion transporting polypeptide 2A1 (OATP2A1/SLCO2A1), a prostaglandin transporter, in facilitating this response is unknown. Here, we investigated the effect of Slco2a1 deficiency on the body core temperature (Tc) and on the PGE2 concentration in hypothalamus interstitial fluid (Cisf) and CSF (Ccsf) of lipopolysaccharide (LPS; 100 µg/kg, i.p.)-treated mice of both sexes. Slco2a1-/- mice did not develop a febrile response. Ccsf was increased in Slco2a1+/+ and Slco2a1-/- mice, and Ccsf of Slco2a1-/- mice was well maintained at 5 h after LPS injection (1160 pg/ml) compared with Slco2a1+/+ mice (316 pg/ml). A microdialysis study revealed that Cisf peaked at 2 h after LPS injection in Slco2a1+/+ mice (841 pg/ml), whereas the increase in Cisf was negligible in Slco2a1-/- mice. The PGE2 plasma concentration in Slco2a1-/- mice (201 pg/ml) was significantly higher than that in Slco2a1+/+ mice (54 pg/ml) at 1 h after LPS injection, whereas the two groups showed similar PGE2 concentrations in the hypothalamus. Strong Oatp2a1 immunoreactivity was observed in F4/80-positive microglia and perivascular cells and in brain capillary endothelial cells. The changes in Tc and Cisf seen in LPS-injected Slco2a1+/+ mice were partially attenuated in monocyte-/macrophage-specific Slco2a1-/- (Slco2a1Fl/Fl/LysMCre/+) mice. Thus, OATP2A1 facilitates the LPS-induced febrile response by maintaining a high level of Cisf, possibly by regulating PGE2 secretion from F4/80-positive glial cells and/or facilitating PGE2 transport across the blood-brain barrier. These findings suggest that OATP2A1 is a useful therapeutic target for neuroinflammation.SIGNIFICANCE STATEMENT Fever is a physiological response caused by pyrogen-induced release of prostaglandin E2 (PGE2) in the hypothalamus, which plays a central role in regulating the set-point of body temperature. However, it is unclear whether the prostaglandin transporter OATP2A1/SLCO2A1 is involved in this response. We show here that LPS-induced fever is associated with increased PGE2 concentration in hypothalamus interstitial fluid (Cisf), but not in CSF (Ccsf), by means of a microdialysis study in global Slco2a1-knock-out mice and monocyte-/macrophage-specific Slco2a1-knock-out mice. The results suggest that OATP2A1 serves as a regulator of Cisf in F4/80-positive glial cells. OATP2A1 was detected immunohistochemically in brain capillary endothelial cells and, therefore, may also play a role in PGE2 transport across the blood-brain barrier.

Effects of Anticholinergic Drugs Used for the Therapy of Overactive Bladder on P-Glycoprotein Activity.

We evaluated the effects of anticholinergic drugs principally used for the therapy of overactive bladder (OAB) on the activity of P-glycoprotein, an efflux transport protein, in Caco-2 cells. The time-dependent changes in the fluorescence of residual rhodamine 123, a P-glycoprotein activity marker, in the apical region of Caco-2 cells were measured in the presence of anticholinergic drugs using time-lapse confocal laser scanning microscopy. The effect of anticholinergic drugs on human P-glycoprotein ATPase activity was also measured. The fluorescence of residual rhodamine 123 in untreated Caco-2 cells decreased over time. The gradual decrease in the fluorescence was significantly inhibited by treatment with cyclosporine A, darifenacin, and trospium. In contrast, oxybutynin, N-desethyl-oxybutynin (DEOB), propiverine, and its active metabolites (M-1, M-2), imidafenacin, solifenacin, or tolterodine had little effect on the efflux of rhodamine 123. P-Glycoprotein ATPase activity was increased by darifenacin. Darifenacin and trospium reduced the rhodamine 123 transfer across the apical cell membrane. These data suggest that darifenacin and trospium interact with P-glycoprotein. Additionally, darifenacin influenced P-glycoprotein ATPase activity. These results suggest that darifenacin may be a substrate of P-glycoprotein. This study is the first paper to test simultaneously the effects of 10 anticholinergic drugs used currently for the therapy of OAB, on the P-glycoprotein.

Free T3 to free T4 ratio less than 2.0 suggests low T3 syndrome rather than central hypothyroidism from the age of two to eighteen years.

No serological cut-off exists to separate low T3 syndrome (LT) and central hypothyroidism (CH). The objective of this retrospective study was to propose such a cut-off. The first participant group comprised 52 patients from the age of six to twenty years. This group consisted of patients of 36 anorexia nervosa with LT and 16 CH. The second participant groups comprised 229 patients of all the same range of ages at the same hospital and included LT (n = 58) and CH (n = 4) patients, respectively. The third group of participants comprised 125 LT and 27 CH patients at the same hospital at all ages less than eighteen years. The last group of participants comprised 10 CH patients from the other two hospitals. The main outcome measure was fT3/fT4 ratio (pg/mL, ng/dL respectively). This ratio in the first group was significantly different (p < 0.05) between LT and CH. When the cut off value of fT3/fT4 was set as 2.0, the sensitivity of the LT and CH patients in the second group was 62% and 100%, respectively. This cut-off value of 2.0 was useful for distinguishing LT from CH only above the age of two years, as shown in the third group. The fT3/fT4 in 10 subjects with CH in the last group, aged 2 to 7 years, ranged from 2.55 to 7.71. In conclusion, fT3/fT4 less than 2.0 suggests LT rather than CH for patients from the age of two to eighteen years.

Histamine elimination from the cerebrospinal fluid across the blood-cerebrospinal fluid barrier: involvement of plasma membrane monoamine transporter (PMAT/SLC29A4).

The elimination of histamine, an excitatory neurotransmitter, from the brain/CSF across the blood-brain barrier and blood-CSF barrier (BCSFB) was investigated using Wistar rats, which were anesthetized with pentobarbital sodium. An in vivo intracerebral microinjection study suggested that there was only partial efflux of [3 H]histamine from the rat brain across the blood-brain barrier. The [3 H]histamine elimination clearance from the rat CSF was 3.8-fold greater than that of a CSF bulk flow marker, and the elimination of [3 H]histamine was significantly inhibited by the co-administration of unlabeled histamine, suggesting the involvement of a carrier-mediated process in histamine elimination from the CSF. The uptake study of [3 H]histamine by the isolated rat choroid plexus revealed histamine elimination from the CSF across the BCSFB. The [3 H]histamine uptake by TR-CSFB3 cells, a model cell line for the BCSFB, exhibited temperature-dependent and saturable kinetics, suggesting the involvement of carrier-mediated transport of histamine at the BCSFB. In the inhibition study, [3 H]histamine uptake by TR-CSFB3 cells was significantly inhibited by substrates and/or inhibitors of plasma membrane monoamine transporter (PMAT/SLC29A4), but not affected by substrates of organic cation transporters. These results suggest the elimination of histamine from the CSF via plasma membrane monoamine transporter at the BCSFB.

Bladder endothelin-1 receptor binding of bosentan and ambrisentan.

The present study aimed to characterize bladder endothelin-1 (ET-1) receptor binding of clinically used ET-1 receptor antagonists by using [(125)I]ET-1. The inhibition of specific [(125)I]ET-1 binding was measured in the presence of ET-1 and its receptor antagonists. Specific binding of [(125)I]ET-1 in rat bladder was saturable and of high affinity, which characterized selective labeling of bladder ET-1 receptors. ET-1, bosentan, ambrisentan, and CI-1020 inhibited specific [(125)I]ET-1 binding in a concentration-dependent manner at nanomolar ranges of IC50. Nonlinear least squares regression analysis revealed the presence of high- and low-affinity ET-1 receptor sites for ambrisentan and CI-1020. Bosentan and ambrisentan significantly increased the dissociation constant for bladder [(125)I]ET-1 binding without affecting maximal number of binding sites (Bmax). Thus, bosentan and ambrisentan seem to bind to bladder ET-1 receptor in a competitive and reversible manner. Oral administration of bosentan caused a dose-dependent decrease in Bmax for bladder [(125)I]ET-1 binding, suggesting significant binding of bladder ET-1 receptors in vivo. A significant amount of pharmacologically relevant ET-1 receptors may exist in the bladder. These receptors may be implicated in the pathogenesis of lower urinary tract symptoms and may also be promising targets for the development of therapeutic agents.

Muscarinic receptor binding of the novel radioligand, [3h]imidafenacin in the human bladder and parotid gland.

The aim of the current study was to demonstrate highly specific and direct binding activity of tritium ([(3)H])-labeled imidafenacin for labeling muscarinic receptors in human bladder and parotid gland. Specific binding of [(3)H]imidafenacin in human tissues was saturable, reversible, and of high affinity. The Kd value for specific [(3)H]imidafenacin binding in the human bladder was approximately 3 times higher than that in the parotid gland. Unlabeled imidafenacin as well as the clinically used antimuscarinic agents, oxybutynin, tolterodine, and solifenacin, competed with [(3)H]imidafenacin for binding sites in the human bladder and parotid gland in a concentrationdependent manner, which indicated pharmacological specificity of [(3)H]imidafenacin binding sites. The Ki for imidafenacin in the human bladder approximately corresponded to pharmacological potency for the competitive blockade of carbachol-induced contractions of bladder, indicating a close correlation between binding affinity of imidafenacin to bladder muscarinic receptors and its pharmacological effects in the bladder. In conclusion, the current study is the first to provide direct evidence to demonstrate that imidafenacin bound muscarinic receptors in the human bladder, supporting its clinical relevance as a therapeutic agent for overactive bladder. [(3)H]Imidafenacin may also be a useful radioligand for labeling the M3 subtype of muscarinic receptors with higher selectivity than other radioligands.

Proton-coupled organic cation antiporter-mediated uptake of apomorphine enantiomers in human brain capillary endothelial cell line hCMEC/D3.

R(-)-Apomorphine is a dopamine agonist used for rescue management of motor function impairment associated with levodopa therapy in Parkinson's disease patients. The aim of this study was to examine the role of proton-coupled organic cation antiporter in uptake of R(-)-apomorphine and its S-enantiomer in human brain, using human endothelial cell line hCMEC/D3 as a model. Uptake of R(-)- or S(+)-apomorphine into hCMEC/D3 cells was measured under various conditions to evaluate its time-, concentration-, energy- and ion-dependency. Inhibition by selected organic cations was also examined. Uptakes of both R(-)- and S(+)-apomorphine increased with time. The initial uptake velocities of R(-)- and S(+)-apomorphine were concentration-dependent, with similar Km and Vmax values. The cell-to-medium (C/M) ratio of R(-)-apomorphine was significantly reduced by pretreatment with sodium azide, but was not affected by replacement of extracellular sodium ion with N-methylglucamine or potassium. Intracellular alkalization markedly reduced the uptake, while intracellular acidification increased it, suggesting that the uptake is driven by an oppositely directed proton gradient. The C/M ratio was significantly decreased by amantadine, verapamil, pyrilamine and diphenhydramine (substrates or inhibitors of proton-coupled organic cation antiporter), while tetraethylammonium (substrate of organic cation transporters (OCTs)) and carnitine (substrate of carnitine/organic cation transporter 2; (OCTN2)) had no effect. R(-)-Apomorphine uptake was competitively inhibited by diphenhydramine. Our results indicate that R(-)-apomorphine transport in human blood-brain barrier (BBB) model cells is similar to S(+)-apomorphine uptake. The transport was dependent on an oppositely directed proton gradient, but was sodium- or membrane potential-independent. The transport characteristics were consistent with involvement of the previously reported proton-coupled organic cation antiporter.

Endothelin-1 receptors in rat tissues: characterization by bosentan, ambrisentan and CI-1020.

The present study aimed to characterize comparatively endothelin-1 (ET-1) receptors in rat tissues by radioligand binding assay using [(125)I]ET-1 and to examine receptor binding after oral administration of bosentan. Significant amount of specific [(125)I]ET-1 binding was detected in the lung, heart, kidney, bladder and cerebral cortex of rats. ET-1, bosentan, ambrisentan, and CI-1020 inhibited specific [(125)I]ET-1 binding in these tissues in a concentration-dependent manner. The Hill coefficients of each agent in the rat lung and cerebral cortex and those of bosentan and ET-1 in the heart, kidney and bladder were close to unity, while the Hill coefficients of ambrisentan and CI-1020 in the heart, kidney and bladder were less than one. The nonlinear least squares regression analysis revealed the presence of high- and low-affinity ET-1 receptor sites in these tissues for ambrisentan and CI-1020. Oral administration of bosentan caused a dose-dependent decrease in specific [(125)I]ET-1 binding in the rat lung, kidney and bladder, suggesting significant binding of the tissue ET-1 receptors in vivo. In conclusion, it has been shown that a significant amount of pharmacologically relevant ET-1 receptors may exist in rat tissues and that ET-1 receptor antagonists such as bosentan at pharmacological doses may exert some pharmacological effects by binding these ET-1 receptors.

Optical Control of Mononegavirus Gene Expression and Replication.

Mononegaviruses are promising tools as oncolytic and transgene vectors for gene therapy and regenerative medicine. However, when mononegaviruses are used for therapeutic applications, the viral activity must be strictly controlled due to concerns about toxicity and severe side effects. With this technology, mononegavirus vectors can be grown where they are intended and can be easily removed when they are no longer needed. In particular, a photoswitch protein called Magnet (consisting of two magnet domains) is incorporated into the hinge region between the connector and methyltransferase domains of the mononegavirus polymerase protein (L protein) to disrupt the L protein functions. Blue light (470 ± 20 nm) irradiation causes the dimerization of the two magnet domains, and the L protein is restored to activity, allowing viral gene expression and virus replication. Since the magnet domains' dimerization is reversible, viral gene expression and replication cease when blue light irradiation is stopped.

Development of simultaneous determination of dopamine 2, histamine 1, and muscarinic acetylcholine receptor occupancies by antipsychotics using liquid chromatography with tandem mass spectrometry.

Receptor occupancy is an indicator of antipsychotic efficacy and safety. It is desirable to simultaneously determine the occupancy of multiple brain receptors as an indicator of the efficacy and central side effects of antipsychotics because many of these drugs have binding affinities for various receptors, such as dopamine 2 (D2), histamine 1 (H1), and muscarinic acetylcholine (mACh) receptors. The purpose of this study was to develop a method for the simultaneous measurement of multiple receptor occupancies in the brain by the simultaneous quantification of unlabeled tracer levels using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Rats were pre-administered with a vehicle, displacer, or olanzapine, and mixed solutions of raclopride, doxepin, and 3-quinuclidinyl benzilate (3-QNB) were administered (3, 10, and 30 µg/kg). The brain tissue and plasma tracer concentrations were quantified 45 min later using LC-MS/MS, and the binding potential was calculated. The highest binding potential was observed at 3 µg/kg raclopride, 10 µg/kg doxepin, and 30 µg/kg 3-QNB. Tracer-specific binding at these optimal tracer doses in the cerebral cortex was markedly reduced by pre-administration of displacers. D2, H1, and mACh receptor occupancy by olanzapine increased in a dose-dependent manner, reaching 70-95%, 19-43%, and 12-45%, respectively, at an olanzapine dose range of 3-10 mg/kg. These results suggest that simultaneous determination of in vivo D2, H1, and mACh receptor occupancy is possible using LC-MS/MS.

Predicting muscarinic receptor occupancy in human bladder mucosa from urinary concentrations of antimuscarinic agents for overactive bladder.

To assess the pharmacologically relevant and selective muscarinic receptor occupancy in the bladder mucosa, we considered not only plasma drug concentrations but also urinary drug concentrations. The purpose of this study was to predict muscarinic receptor occupancy in the human bladder mucosa based on urinary concentrations in response to clinical dosages of antimuscarinic agents used to treat overactive bladder. The calculated mean plasma or serum unbound steady state concentrations were 0.06-11 nM in clinical dosages of five antimuscarinic agents. Urinary concentrations calculated from the mean plasma or serum and renal clearance ranged between 19 nM and 2 µM, which were >10-fold higher than the Ki values for bladder muscarinic receptors excluding propiverine. Bladder mucosal muscarinic receptor occupancy estimated from the urinary concentrations and the Ki values was >90 % at a steady state in clinical dosages of five antimuscarinic agents. The bladder muscarinic receptor occupancy was higher than that in the parotid gland calculated based on the mean plasma or serum unbound concentrations and Ki values for muscarinic receptors in the parotid gland. These results suggest that sufficient and selective muscarinic receptor occupancy by antimuscarinic agents, to exert pharmacological effects, in the bladder mucosa can be predicted using urinary concentrations.

Investigating the Transepithelial Transport and Enzymatic Stability of Lactononadecapeptide (NIPPLTQTPVVVPPFLQPE), a 19-Amino Acid Casein-Derived Peptide in Caco-2 Cells.

Lactononadecapeptide (LNDP; NIPPLTQTPVVVPPFLQPE), a casein-derived peptide comprising 19 residues, is known for its capacity to enhance cognitive function. This study aimed to explore the transepithelial transport and stability of LNDP. Results showed that LNDP retained over 90% stability after 2 h of treatment with gastrointestinal enzymes. The stability of LNDP on Caco-2 cell monolayers ranged from 93.4% ± 0.9% to 101.1% ± 1.2% over a period of 15-60 min, with no significant differences at each time point. The permeability of LNDP across an artificial lipid membrane was very low with the effective permeability of 3.6 × 10-11 cm/s. The Caco-2 assay demonstrated that LNDP could traverse the intestinal epithelium, with an apparent permeability of 1.22 × 10-6 cm/s. Its transport was significantly inhibited to 67.9% ± 5.0% of the control by Gly-Pro, a competitor of peptide transporter 1 (PEPT1). Furthermore, PEPT1 knockdown using siRNA significantly inhibited LNDP transport by 77.6% ± 1.9% in Caco-2 cell monolayers. The LNDP uptake in PEPT1-expressing HEK293 cells was significantly higher (54.5% ± 14.6%) than that in mock cells. These findings suggest that PEPT1 plays a crucial role in LNDP transport, and LNDP exhibits good resistance to gastrointestinal enzymes.

Phylogenetic analysis of the promoter element 2 of paramyxo- and filoviruses.

Paramyxo- and filovirus genomes are equipped with bipartite promoters at their 3' ends to initiate RNA synthesis. The two elements, the primary promoter element 1 (PE1) and the secondary promoter element 2 (PE2), are separated by a spacer region that must be precisely a multiple of 6 nucleotides (nts), indicating these viruses adhere to the "rule of six." However, our knowledge of PE2 has been limited to a narrow spectrum of virus species. In this study, a comparative analysis of 1,647 paramyxoviral genomes from a public database revealed that the paramyxovirus PE2 can be clearly categorized into two distinct subcategories: one marked by C repeats at every six bases (exclusive to the subfamily Orthoparamyxovirinae) and another characterized by CG repeats every 6 nts (observed in the subfamilies Avulavirinae and Rubulavirinae). This unique pattern collectively mirrors the evolutionary lineage of these subfamilies. Furthermore, we showed that PE2 of the Rubulavirinae, with the exception of mumps virus, serves as part of the gene-coding region. This may be due to the fact that the Rubulavirinae are the only paramyxoviruses that cannot propagate without RNA editing. Filoviruses have three to eight consecutive uracil repeats every six bases (UN5) in PE2, which is located in the 3' end region of the genome. We obtained PE2 sequences from 2,195 filoviruses in a public database and analyzed the sequence conservation among virus species. Our results indicate that the continuity of UN5 hexamers is consistently maintained with a high degree of conservation across virus species. IMPORTANCE: The genomic intricacies of paramyxo- and filoviruses are highlighted by the bipartite promoters-promoter element 1 (PE1) and promoter element 2 (PE2)-at their 3' termini. The spacer region between these elements follows the "rule of six," crucial for genome replication. By a comprehensive analysis of paramyxoviral genome sequences, we identified distinct subcategories of PE2 based on C and CG repeats that were specific to Orthoparamyxovirinae and Avulavirinae/Rubulavirinae, respectively, mirroring their evolutionary lineages. Notably, the PE2 of Rubulavirinae is integrated into the gene-coding region, a unique trait potentially linked to its strict dependence on RNA editing for virus growth. This study also focused on the PE2 sequences in filovirus genomes. The strict conservation of the continuity of UN5 among virus species emphasizes its crucial role in viral genome replication.