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Fluids and Barriers of the CNS Apr 2024The blood-brain barrier (BBB) is pivotal for the maintenance of brain homeostasis and it strictly regulates the cerebral transport of a wide range of endogenous...
BACKGROUND
The blood-brain barrier (BBB) is pivotal for the maintenance of brain homeostasis and it strictly regulates the cerebral transport of a wide range of endogenous compounds and drugs. While fasting is increasingly recognized as a potential therapeutic intervention in neurology and psychiatry, its impact upon the BBB has not been studied. This study was designed to assess the global impact of fasting upon the repertoire of BBB transporters.
METHODS
We used a combination of in vivo and in vitro experiments to assess the response of the brain endothelium in male rats that were fed ad libitum or fasted for one to three days. Brain endothelial cells were acutely purified and transcriptionaly profiled using RNA-Seq. Isolated brain microvessels were used to assess the protein expression of selected BBB transporters through western blot. The molecular mechanisms involved in the adaptation to fasting were investigated in primary cultured rat brain endothelial cells. MCT1 activity was probed by in situ brain perfusion.
RESULTS
Fasting did not change the expression of the main drug efflux ATP-binding cassette transporters or P-glycoprotein activity at the BBB but modulated a restrictive set of solute carrier transporters. These included the ketone bodies transporter MCT1, which is pivotal for the brain adaptation to fasting. Our findings in vivo suggested that PPAR δ, a major lipid sensor, was selectively activated in brain endothelial cells in response to fasting. This was confirmed in vitro where pharmacological agonists and free fatty acids selectively activated PPAR δ, resulting in the upregulation of MCT1 expression. Moreover, dosing rats with a specific PPAR δ antagonist blocked the upregulation of MCT1 expression and activity induced by fasting.
CONCLUSIONS
Altogether, our study shows that fasting affects a selected set of BBB transporters which does not include the main drug efflux transporters. Moreover, we describe a previously unknown selective adaptive response of the brain vasculature to fasting which involves PPAR δ and is responsible for the up-regulation of MCT1 expression and activity. Our study opens new perspectives for the metabolic manipulation of the BBB in the healthy or diseased brain.
Topics: Rats; Male; Animals; Blood-Brain Barrier; PPAR delta; Endothelial Cells; Membrane Transport Proteins; Brain; Fasting
PubMed: 38589879
DOI: 10.1186/s12987-024-00526-8 -
Biochemical and Biophysical Research... May 2024P-glycoprotein (P-gp) is an ATP-binding cassette transporter known for its roles in expelling xenobiotic compounds from cells and contributing to cellular drug...
P-glycoprotein (P-gp) is an ATP-binding cassette transporter known for its roles in expelling xenobiotic compounds from cells and contributing to cellular drug resistance through multidrug efflux. This mechanism is particularly problematic in cancer cells, where it diminishes the therapeutic efficacy of anticancer drugs. P-gp inhibitors, such as elacridar, have been developed to circumvent the decrease in drug efficacy due to P-gp efflux. An earlier study reported the cryo-EM structure of human P-gp-Fab (MRK-16) complex bound by two elacridar molecules, at a resolution of 3.6 Å. In this study, we have obtained a higher resolution (2.5 Å) structure of the P-gp- Fab (UIC2) complex bound by three elacridar molecules. This finding, which exposes a larger space for compound-binding sites than previously acknowledged, has significant implications for the development of more selective inhibitors and enhances our understanding of the compound recognition mechanism of P-gp.
Topics: Humans; Acridines; ATP Binding Cassette Transporter, Subfamily B, Member 1; Cryoelectron Microscopy; Tetrahydroisoquinolines
PubMed: 38579618
DOI: 10.1016/j.bbrc.2024.149855 -
Cureus Mar 2024Direct oral anticoagulants (DOACs), such as apixaban, are used for the prevention and management of thromboembolic diseases. Here, we present a case of a 72-year-old...
Direct oral anticoagulants (DOACs), such as apixaban, are used for the prevention and management of thromboembolic diseases. Here, we present a case of a 72-year-old African American woman who presented to the hospital with shortness of breath and precordial chest pain for three days. The patient was diagnosed with volume overload associated with the progression of chronic kidney disease (CKD) and subsequently admitted to the hospital. Since the patient failed to adequately respond to diuretics, hemodialysis was initiated. During the hospital stay, she developed paroxysmal atrial fibrillation. Along with amiodarone, apixaban was started for primary stroke prophylaxis. Within 72 hours, the patient developed worsening chest pain. An echocardiogram revealed a large pericardial effusion with cardiac tamponade. She was taken for an emergent open pericardial window placement to relieve cardiac tamponade, where 600 mL of blood was drained. Considering the timeline of the development of a large bloody pericardial effusion following initiation of apixaban, spontaneous hemorrhagic cardiac tamponade attributed to the use of apixaban was diagnosed. The patient was eventually taken off all anticoagulants. In considering potential mechanisms, impaired hepatic and renal metabolism of apixaban could be factored in this case. In addition, CKD can increase bleeding risk, due to platelet dysfunction and impaired interaction of von Willebrand factor with GPIIb-IIIa. Moreover, renal secretion of apixaban is mediated by p-glycoprotein and amiodarone is an inhibitor of this protein. Although extremely rare, spontaneous hemorrhagic cardiac tamponade can occur with the use of DOACs, such as apixaban. Prompt recognition and urgent treatment remain keys to avoiding adverse patient outcomes.
PubMed: 38571853
DOI: 10.7759/cureus.55476 -
Frontiers in Chemistry 2024The process of developing of new drugs is greatly hampered by their inadequate physicochemical, pharmacokinetic, and intrinsic characteristics. In this regard, the...
The process of developing of new drugs is greatly hampered by their inadequate physicochemical, pharmacokinetic, and intrinsic characteristics. In this regard, the selected chloro indolinone, (Z)-6-chloro-3-(2-chlorobenzylidene)indolin-2-one (C1), and nitro indolinone, (Z)-6-chloro-3-(2-nitrobenzylidene)indolin-2-one (C2), were subjected to SwissADME and density function theory (DFT) analysis. For compounds C1 and C2, the BOILED-Egg pharmacokinetic model predicted intestinal absorption, blood-brain barrier (BBB) penetration, and p-glycoprotein interaction. According to the physicochemical analysis, C1 has exceptional drug-like characteristics suitable for oral absorption. Despite only being substrates for some of the major CYP 450 isoforms, compounds C1 and C2 were anticipated to have strong plasma protein binding and efficient distribution and block these isoforms. The DFT study using the B3LYP/6-311G(d,p) approach with implicit water effects was performed to assess the structural features, electronic properties, and global reactivity parameters (GRP) of C1 and C2. The DFT results provided further support for other studies, implying that C2 is more water-soluble than C1 and that both compounds can form hydrogen bonds and (weak) dispersion interactions with other molecules, such as solvents and biomolecules. Furthermore, the GRP study suggested that C1 should be more stable and less reactive than C2. A concentration-dependent 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity was shown by both C1 and C2. In brief, this finding has provided a strong foundation to explore further the therapeutic potential of these molecules against a variety of human disorders.
PubMed: 38562526
DOI: 10.3389/fchem.2024.1360719 -
Frontiers in Molecular Biosciences 2024The human multidrug transporter P-glycoprotein (P-gp) is physiologically essential and of key relevance to biomedicine. Recent structural studies have shed light on the...
The human multidrug transporter P-glycoprotein (P-gp) is physiologically essential and of key relevance to biomedicine. Recent structural studies have shed light on the mode of inhibition of the third-generation inhibitors for human P-gp, but the molecular mechanism by which these inhibitors enter the transmembrane sites remains poorly understood. In this study, we utilized all-atom molecular dynamics (MD) simulations to characterize human P-gp dynamics under a potent inhibitor, tariquidar, bound condition, as well as the atomic-level binding pathways in an explicit membrane/water environment. Extensive unbiased simulations show that human P-gp remains relatively stable in tariquidar-free and bound states, while exhibiting a high dynamic binding mode at either the drug-binding pocket or the regulatory site. Free energy estimations by partial nudged elastic band (PNEB) simulations and Molecular Mechanics Generalized Born Surface Area (MM/GBSA) method identify two energetically favorable binding pathways originating from the cytoplasmic gate with an extended tariquidar conformation. Interestingly, free tariquidar in the lipid membrane predominantly adopts extended conformations similar to those observed at the regulatory site. These results suggest that membrane lipids may preconfigure tariquidar into an active ligand conformation for efficient binding to the regulatory site. However, due to its conformational plasticity, tariquidar ultimately moves toward the drug-binding pocket in both pathways, explaining how it acts as a substrate at low concentrations. Our molecular findings propose a membrane-assisted mechanism for the access and binding of the third-generation inhibitors to the binding sites of human P-gp, and offer deeper insights into the molecule design of more potent inhibitors against P-gp-mediated drug resistance.
PubMed: 38560519
DOI: 10.3389/fmolb.2024.1364494 -
Scientific Reports Mar 2024P-glycoprotein (P-gp) imparts multi-drug resistance (MDR) on the cancers cell and malignant tumor clinical therapeutics. We report a class of newly designed and...
P-glycoprotein (P-gp) imparts multi-drug resistance (MDR) on the cancers cell and malignant tumor clinical therapeutics. We report a class of newly designed and synthesized oxygen-heterocyclic-based pyran analogues (4a-l) bearing different aryl/hetaryl-substituted at the 1-postion were synthesized, aiming to impede the P-gp function. These compounds (4a-l) have been tested against cancerous PC-3, SKOV-3, HeLa, and MCF-7/ADR cell lines as well as non-cancerous HFL-1 and WI-38 cell lines to determine their anti-proliferative potency.The findings demonstrated the superior potency of 4a-c with 4-F, 2-Cl, and 3-Cl derivatives and 4h,g with 4-NO, 4-MeO derivatives against PC-3, SKOV-3, HeLa, and MCF-7/ADR cell lines.Compounds 4a-c were tested for P-gp inhibition and demonstrated significant vigour against MCF-7/ADR cells with IC = 5.0-10.7 μM. The Rho123 accumulation assay showed that compounds 4a-c adequately inhibited P-gp function, as predicted. Furthermore, 4a or 4b administration resulted in MCF-7/ADR cell accumulation in the S phase, while compound 4c induced apoptosis by causing cell cycle arrest at G2/M. The molecular docking was applied to understand the likely modes of action and guide us in the rational design of more potent analogs. The investigate derivatives showed their good binding potential for p-gp active site with excellent docking scores and interactions. Finally, the majority of investigated derivatives 4a-c derivatives showed high oral bioavailability, but they did not cross the blood-brain barrier. These results suggest that they have favorable pharmacokinetic properties. Therefore, these compounds could serve as leads for designing more potent and stable drugs in the future.
Topics: Humans; MCF-7 Cells; Oxygen; Molecular Docking Simulation; Drug Resistance, Neoplasm; Drug Resistance, Multiple; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily B; Antineoplastic Agents; Doxorubicin
PubMed: 38555345
DOI: 10.1038/s41598-024-56197-w -
Acta Pharmaceutica (Zagreb, Croatia) Mar 2024A diastereomeric mixture of racemic 3-phthalimido--lactam / was synthesized by the Staudinger reaction of carboxylic acid activated with 2-chloro-1-methylpyridinium...
A diastereomeric mixture of racemic 3-phthalimido--lactam / was synthesized by the Staudinger reaction of carboxylic acid activated with 2-chloro-1-methylpyridinium iodide and imine . The amino group at the C3 position of the -lactam ring was used for further structural upgrade. --lactam ureas were prepared by the condensation reaction of the amino group of -lactam ring with various aromatic and aliphatic isocyanates. Antimicrobial activity of compounds was evaluated and neither antibacterial nor antifungal activity were observed. Several of the newly synthesized --lactam ureas , , , , , , and were evaluated for antiproliferative activity against liver hepatocellular carcinoma (HepG2), ovarian carcinoma (A2780), breast adenocarcinoma (MCF7) and untransformed human fibroblasts (HFF1). The -lactam urea showed the most potent antiproliferative activity against the ovarian carcinoma (A2780) cell line. Compounds and exhibited strong cytotoxic effects against human non-tumor cell line HFF1. The -lactam ureas were estimated to be soluble and membrane permeable, moderately lipophilic molecules (log 4.6) with a predisposition to be CYP3A4 and P-glycoprotein substrates. The tools PASS and SwissTargetPrediction could not predict biological targets for compounds with high probability, pointing to the novelty of their structure. Considering low toxicity risk, molecules and can be selected as the most promising candidates for further structure modifications.
Topics: Humans; Female; Molecular Structure; Structure-Activity Relationship; beta-Lactams; Urea; Cell Line, Tumor; Ovarian Neoplasms; Antineoplastic Agents; Carcinoma, Hepatocellular; Liver Neoplasms; Cell Proliferation
PubMed: 38554382
DOI: 10.2478/acph-2024-0008 -
Materials Today. Bio Jun 2024Multi-drug resistance (MDR) in advanced breast cancer (ABC) is triggered by the high expression of P-glycoprotein (P-gp), which reduces intracellular concentration of...
Multi-drug resistance (MDR) in advanced breast cancer (ABC) is triggered by the high expression of P-glycoprotein (P-gp), which reduces intracellular concentration of anti-tumor drugs, in turn preventing oxidative stress damage to cytoplasmic and mitochondrial membranes. It is therefore of clinical relevance to develop P-gp-specific targeted nanocarriers for the treatment of drug resistant ABC. Herein, a drug carrier targeting CD44 and mitochondria was synthesised for the delivery of encequidar (ER, P-gp inhibitor) and paclitaxel (PTX). HT@ER/PTX nanoparticles (ER:PTX molar ratio 1:1) had excellent P-gp inhibition ability and targeted mitochondria to induce apoptosis in MCF-7/PTX cells . Furthermore, HT@ER/PTX nanocarriers showed more anti-tumor efficacy than PTX (Taxol®) in a xenograft mouse model of MCF-7/PTX cells; the tumor inhibitory rates of HT@ER/PTX nanoparticles and Taxol® were 72.64% ± 4.41% and 32.36% ± 4.09%, respectively. The survival of tumor-bearing mice administered HT@ER/PTX nanoparticles was prolonged compared to that of the mice treated with Taxol®. In addition, HT@ER/PTX not only inhibited P-gp-mediated removal of toxic lipid peroxidation byproducts resulting from anti-tumor drugs but also upregulated the expression of mitochondrial dynamics-related protein, fostering oxidative stress damage, which induced activation of the Caspase-3 apoptosis pathway. Our findings indicate that mitochondria targeted co-delivery of anti-tumor drugs and P-gp inhibitors could be a practical approach in treating multi-drug resistance in ABC.
PubMed: 38545262
DOI: 10.1016/j.mtbio.2024.101029 -
Journal of Medicinal Chemistry Apr 2024The blood-brain barrier (BBB) poses a significant obstacle in developing therapeutics for neurodegenerative diseases and central nervous system (CNS) disorders....
The blood-brain barrier (BBB) poses a significant obstacle in developing therapeutics for neurodegenerative diseases and central nervous system (CNS) disorders. P-glycoprotein (P-gp), a multidrug resistance protein, is a critical gatekeeper in the BBB and plays a role in cancer chemoresistance. This paper uses cryo-EM P-gp structures as starting points with an induced fit docking (IFD) model to evaluate 19 pairs of compounds with known P-gp efflux data. The study reveals significant differences in binding energy and sheds light on structural modifications' impact on efflux properties. In the cases examined, fluorine incorporation influences the efflux by altering the molecular conformation rather than proximal heteroatom basicity. Although there are limitations in addressing covalent interactions or when binding extends into the more flexible vestibule region of the protein, the results provide valuable insights and potential strategies to overcome P-gp efflux, contributing to the advancement of drug development for both CNS disorders and cancer therapies.
Topics: Humans; ATP Binding Cassette Transporter, Subfamily B, Member 1; Ligands; ATP Binding Cassette Transporter, Subfamily B; Blood-Brain Barrier; Neoplasms
PubMed: 38544305
DOI: 10.1021/acs.jmedchem.4c00139 -
Pharmaceuticals (Basel, Switzerland) Feb 2024Nalbuphine is associated with a significant risk of respiratory depression. Its central nervous system entry is hindered by P-glycoproteins, and lower P-glycoprotein...
Hyperlipidemia Increases Nalbuphine Brain Accumulation with Multiple Dosing without Affecting Its Analgesic Response-Its Respiratory Depression Potential Should Be Investigated in Future Studies.
Nalbuphine is associated with a significant risk of respiratory depression. Its central nervous system entry is hindered by P-glycoproteins, and lower P-glycoprotein activity is a risk factor for respiratory depression. We assessed the effect of hyperlipidemia on nalbuphine pharmacokinetics, brain and liver uptake, and analgesic response following single (2.5 mg/kg) and multiple (2.5 mg/kg/day for three days) doses in normolipidemic and hyperlipidemic rats. Trends of reduction and increase in nalbuphine C and Vd/F were observed, respectively, in hyperlipidemic rats. Negative correlations were observed between C and serum lipoproteins. Serum-normalized brain and liver levels at 1 h post-dose were lower in hyperlipidemic rats, with brain and liver levels being negatively and positively correlated with TG and HDL, respectively. At steady state, marked nalbuphine accumulation was observed in hyperlipidemic rat brains (R = 1.6) compared with normolipidemic rats (R = 1.1). Nalbuphine analgesic response was not altered by hyperlipidemia at steady state. Caution should be exercised since greater brain accumulation in hyperlipidemic patients treated with nalbuphine could increase their risk of respiratory depression. Our study highlights an unexpected role of lipoproteins in drug absorption and tissue uptake. We also propose a model for reduced nalbuphine absorption based on interaction with intestinal HDL-3.
PubMed: 38543067
DOI: 10.3390/ph17030282