Selective κ Opioid Antagonists nor-BNI, GNTI and JDTic Have Low Affinities for Non-Opioid Receptors and Transporters

Background: Nor-BNI, GNTI and JDTic induce selective κ opioid antagonism that is delayed and extremely prolonged, but some other effects are of rapid onset and brief duration. The transient effects of these compounds differ, suggesting that some of them may be mediated by other targets. Results: In binding assays, the three antagonists showed no detectable affinity (Ki≥10 µM) for most non-opioid receptors and transporters (26 of 43 tested). There was no non-opioid target for which all three compounds shared detectable affinity, or for which any two shared sub-micromolar affinity. All three compounds showed low nanomolar affinity for κ opioid receptors, with moderate selectivity over μ and δ (3 to 44-fold). Nor-BNI bound weakly to the α2C-adrenoceptor (Ki = 630 nM). GNTI enhanced calcium mobilization by noradrenaline at the α1A-adrenoceptor (EC50 = 41 nM), but did not activate the receptor, displace radioligands, or enhance PI hydrolysis. This suggests that it is a functionally-selective allosteric enhancer. GNTI was also a weak M1 receptor antagonist (KB = 3.7 µM). JDTic bound to the noradrenaline transporter (Ki = 54 nM), but only weakly inhibited transport (IC50 = 1.1 µM). JDTic also bound to the opioid-like receptor NOP (Ki = 12 nM), but gave little antagonism even at 30 µM. All three compounds exhibited rapid permeation and active efflux across Caco-2 cell monolayers. Conclusions: Across 43 non-opioid CNS targets, only GNTI exhibited a potent functional effect (allosteric enhancement of α1A-adrenoceptors). This may contribute to GNTI's severe transient effects. Plasma concentrations of nor-BNI and GNTI may be high enough to affect some peripheral non-opioid targets. Nonetheless, κ opioid antagonism persists for weeks or months after these transient effects dissipate. With an adequate pre-administration interval, our results therefore strengthen the evidence that nor-BNI, GNTI and JDTic are highly selective κ opioid antagonists

Induced expression of P-gp and BCRP transporters on brain endothelial cells using transferrin functionalized nanostructured lipid carriers:A first step of a potential strategy for the treatment of Alzheimer's disease

P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP) are two transporters expressed in human neural stem/progenitor cells and at the Blood-Brain Barrier (BBB) level with decreased activity in the early stage of Alzheimer's disease (AD). Both proteins, have a protective role for the embryonic stem cells in the early developmental step, maintaining them in an undifferentiated state, and limit the access of exogenous and endogenous agents to the brain. Recently, MC111 selected from a P-gp/BCRP ligands library was investigated as multitarget strategy for AD treatment, considering its ability to induce the expression and activity of both proteins. However, MC111 clinical use could be limited for the ubiquitous physiological expression of efflux transporters and its moderate toxicity towards endothelial cells. Therefore, a selective MC111 delivery system based on nanostructured lipid carriers (NLC) functionalized with transferrin were developed. The results proved the formation of NLC with average size about 120 nm and high drug encapsulation efficiency (EE% greater than 50). In vitro studies on hCMEC/D3 cells revealed that the MC111 was selectively released by NLC at BBB level and then inducing the activity and expression of BCRP and P-gp, involved in the clearance of amyloid p peptide on brain endothelial cells

Head-to-head comparison of (R)-[C-11]verapamil and [F-18]MC225 in non-human primates, tracers for measuring P-glycoprotein function

PURPOSE: P-glycoprotein (P-gp) function is altered in several brain disorders; thus, it is of interest to monitor the P-gp function in vivo using PET. (R)-[11C]verapamil is considered the gold standard tracer to measure the P-gp function; however, it presents some drawbacks that limit its use. New P-gp tracers have been developed with improved properties, such as [18F]MC225. This study compares the characteristics of (R)-[11C]verapamil and [18F]MC225 in the same subjects.METHODS: Three non-human primates underwent 4 PET scans: 2 with (R)-[11C]verapamil and 2 with [18F]MC225, at baseline and after P-gp inhibition. The 30-min PET data were analyzed using 1-Tissue Compartment Model (1-TCM) and metabolite-corrected plasma as input function. Tracer kinetic parameters at baseline and after inhibition were compared. Regional differences and simplified methods to quantify the P-gp function were also assessed.RESULTS: At baseline, [18F]MC225 VT values were higher, and k2 values were lower than those of (R)-[11C]verapamil, whereas K1 values were not significantly different. After inhibition, VT values of the 2 tracers were similar; however, (R)-[11C]verapamil K1 and k2 values were higher than those of [18F]MC225. Significant regional differences between tracers were found at baseline, which disappeared after inhibition. The positive slope of the SUV-TAC was positively correlated to the K1 and VT of both tracers.CONCLUSION: [18F]MC225 and (R)-[11C]verapamil show comparable sensitivity to measure the P-gp function in non-human primates. Moreover, this study highlights the 30-min VT as the best parameter to measure decreases in the P-gp function with both tracers. [18F]MC225 may become the first radiofluorinated tracer able to measure decreases and increases in the P-gp function due to its higher baseline VT.</p

Liquid biopsy beyond cancer: a miRNA detection in serum with electrochemical chip for non-invasive coeliac disease diagnosis

Coeliac disease is a very common autoimmune disease estimated to affect 1 in 100 people worldwide. It occurs in genetically predisposed people where the ingestion of gluten leads to damage in the small intestine, and it is accurately diagnosticated through duodenal biopsy, an invasive diagnostic method. The liquid biopsy, generally used for monitoring cancer, is an appealing alternative even for autoimmune pathology such as coeliac disease, allowing for detecting disease progression or resistance to treatment. For this reason, an electrochemical peptide nucleic acid (PNA) device combined with a smartphone-assisted potentiostat for non-invasive coeliac disease diagnosis is proposed, by measuring the selected overexpressed miRNA-486-5p in serum, enlarging the application of liquid biopsy in nontumor pathologies. For highly sensitive detection, the polyester-based printed sensor is nanomodified with gold nanoparticles and a synthetic customized PNA probe. The designed sensor can detect the target analyte in the range of 10–100 nM with a limit of detection of 0.7 nM by measuring the variation of the response of the electrochemical mediator hexaammineruthenium in the presence of PNA–miRNA duplex on the nanostructured working electrode surface. The analyses testing serum samples are found in agreement with ones obtained by realxtime quantitative polymerase chain reaction (RT-qPCR), demonstrating the reliability of this innovative electrochemical chip developed

Pharmacokinetic Modeling of [ 18 F]MC225 for Quantification of the P-Glycoprotein Function at the Blood-Brain Barrier in Non-Human Primates with PET

[18F]MC225 has been developed as a weak substrate of P-glycoprotein (P-gp) aimed to measure changes in the P-gp function at the blood–brain barrier with positron emission tomography. This study evaluates [18F]MC225 kinetics in non-human primates and investigates the effect of both scan duration and P-gp inhibition. Three rhesus monkeys underwent two 91-min dynamic scans with blood sampling at baseline and after P-gp inhibition (8 mg/kg tariquidar). Data were analyzed using the 1-tissue compartment model (1-TCM) and 2-tissue compartment model (2-TCM) fits using metabolite-corrected plasma as the input function and for various scan durations (10, 20, 30, 60, and 91 min). The preferred model was chosen according to the Akaike information criterion and the standard errors (%) of the estimated parameters. For the 91-min scan duration, the influx constant K1 increased by 40.7% and the volume of distribution (VT) by 30.4% after P-gp inhibition, while the efflux constant k2 did not change significantly. Similar changes were found for all evaluated scan durations. K1 did not depend on scan duration (10 min—K1 = 0.2191 vs 91 min—K1 = 0.2258), while VT and k2 did. A scan duration of 10 min seems sufficient to properly evaluate the P-gp function using K1 obtained with 1-TCM. For the 91-min scan, VT and K1 can be estimated with a 2-TCM, and both parameters can be used to assess P-gp function

Evaluation of P-glycoprotein function at the blood-brain barrier using [F-18]MC225-PET

P-glycoprotein (P-gp) is an ATP-dependent efflux transporter located at the blood–brain barrier (BBB), involved in the transport of a variety of neurotoxic substances out of the brain. Alterations in P-gp function play an essential role in the pathophysiological mechanisms underlying neurodegenerative disorders

Sugar-based bactericides targeting phosphatidylethanolamine-enriched membranes

Free PMC Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6242839/Anthrax is an infectious disease caused by Bacillus anthracis, a bioterrorism agent that develops resistance to clinically used antibiotics. Therefore, alternative mechanisms of action remain a challenge. Herein, we disclose deoxy glycosides responsible for specific carbohydrate-phospholipid interactions, causing phosphatidylethanolamine lamellar-to-inverted hexagonal phase transition and acting over B. anthracis and Bacillus cereus as potent and selective bactericides. Biological studies of the synthesized compound series differing in the anomeric atom, glycone configuration and deoxygenation pattern show that the latter is indeed a key modulator of efficacy and selectivity. Biomolecular simulations show no tendency to pore formation, whereas differential metabolomics and genomics rule out proteins as targets. Complete bacteria cell death in 10 min and cellular envelope disruption corroborate an effect over lipid polymorphism. Biophysical approaches show monolayer and bilayer reorganization with fast and high permeabilizing activity toward phosphatidylethanolamine membranes. Absence of bacterial resistance further supports this mechanism, triggering innovation on membrane-targeting antimicrobials.The European Union is gratefully acknowledged for the support of the project “Diagnostic and Drug Discovery Initiative for Alzheimer’s Disease” (D3i4AD), FP7-PEOPLE-2013-IAPP, GA 612347. We thank the Management Authorities of the European Regional Development Fund and the National Strategic Reference Framework for the support of the Incentive System - Research and Technological Development Co-Promotion FACIB Project number 21457. Fundação para a Ciência e a Tecnologia is also acknowledged for the support of projects UID/Multi/00612/2013, FCT/UID/ Multi/04046/2013, IF/00808/2013/CP1159/CT0003, PTDC/BBBBQB/6071/2014, as well as for the post-doc grant SFRH/BPD/42567/2007 (A.M.), the Ph.D. grants SFRH/BDE/51998/2012 (C.D.), and SFRH/BDE/51957/2012 (J.P.P.), both co-sponsored by CIPAN, and also for the Ph.D. grant SFRH/BD/116614/2016 (R.N.).info:eu-repo/semantics/publishedVersio