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A complicated complex: Ion channels, voltage sensing, cell membranes and peptide inhibitors. Neurosci Lett 2018; 679:35-47. [DOI: 10.1016/j.neulet.2018.04.030] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/11/2018] [Accepted: 04/17/2018] [Indexed: 01/04/2023]
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van Meer BJ, de Vries H, Firth KSA, van Weerd J, Tertoolen LGJ, Karperien HBJ, Jonkheijm P, Denning C, IJzerman AP, Mummery CL. Small molecule absorption by PDMS in the context of drug response bioassays. Biochem Biophys Res Commun 2017; 482:323-328. [PMID: 27856254 PMCID: PMC5240851 DOI: 10.1016/j.bbrc.2016.11.062] [Citation(s) in RCA: 265] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 11/11/2016] [Indexed: 02/06/2023]
Abstract
The polymer polydimethylsiloxane (PDMS) is widely used to build microfluidic devices compatible with cell culture. Whilst convenient in manufacture, PDMS has the disadvantage that it can absorb small molecules such as drugs. In microfluidic devices like "Organs-on-Chip", designed to examine cell behavior and test the effects of drugs, this might impact drug bioavailability. Here we developed an assay to compare the absorption of a test set of four cardiac drugs by PDMS based on measuring the residual non-absorbed compound by High Pressure Liquid Chromatography (HPLC). We showed that absorption was variable and time dependent and not determined exclusively by hydrophobicity as claimed previously. We demonstrated that two commercially available lipophilic coatings and the presence of cells affected absorption. The use of lipophilic coatings may be useful in preventing small molecule absorption by PDMS.
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Affiliation(s)
- B J van Meer
- Dept. of Anatomy and Embryology, Leiden University Medical Centre, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands.
| | - H de Vries
- Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands.
| | - K S A Firth
- Dept. of Stem Cell Biology, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
| | - J van Weerd
- LipoCoat B.V., PO Box 217, 7500 AE, Enschede, The Netherlands.
| | - L G J Tertoolen
- Dept. of Anatomy and Embryology, Leiden University Medical Centre, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands.
| | - H B J Karperien
- LipoCoat B.V., PO Box 217, 7500 AE, Enschede, The Netherlands; Dept. of Developmental BioEngineering, University of Twente, Driernerlolaan 5, 7522 NB, Enschede, The Netherlands.
| | - P Jonkheijm
- LipoCoat B.V., PO Box 217, 7500 AE, Enschede, The Netherlands; Dept. of Molecular Nanofabrication, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
| | - C Denning
- Dept. of Stem Cell Biology, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
| | - A P IJzerman
- Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands.
| | - C L Mummery
- Dept. of Anatomy and Embryology, Leiden University Medical Centre, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands; Dept. of Applied Stem Cell Technologies, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
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Abstract
Ligand-receptor interactions are customarily described by equations that apply to solutes. Yet, most receptors are present in cell membranes so that sufficiently lipophilic ligands could reach the receptor by a two-dimensional approach within the membrane. As summarized in this review, this may affect the ligand-receptor interaction in many ways. Biophysicians calculated that, compared to a three-dimensional approach from the liquid phase, such approach could alter the time the ligands need to find a receptor. Biochemists found that ligand incorporation in lipid bilayers modifies their conformation. This, along with the depth at which the ligands reside in the bilayer, will affect the probability of successful receptor interaction. Novel mechanisms were also introduced, including "exosite" binding and ligand translocation between the receptor's alpha-helical transmembrane domains. Pharmacologists focused attention at ligand concentrations in membrane, their adsorption and release rates and the effects thereof on ligand potency and residence time at the receptor.
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Affiliation(s)
- G Vauquelin
- Department of Molecular and Biochemical Pharmacology, Institute for Molecular Biology and Biotechnology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussel, Belgium.
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Makriyannis A, Guo J, Tian X. Albumin enhances the diffusion of lipophilic drugs into the membrane bilayer. Life Sci 2005; 77:1605-11. [PMID: 15964025 DOI: 10.1016/j.lfs.2005.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In earlier work, we reported on the manner with which lipophilic drug molecules interact with the cell membrane in order to (a) enter the bilayer and laterally diffuse to their respective protein sites of action, or (b) penetrate this biological barrier to reach the cell interior. A remaining uncertainty is how lipophilic molecules reach the hydrophobic membrane core after traversing the aqueous medium and membrane polar surface. Here we present preliminary data using deuterium NMR, demonstrating the role of bovine serum albumin in facilitating this process. Our observation allows us to postulate a mechanism by which the passive transport of lipophilic ligands across the membrane can be greatly enhanced through the assistance of carrier proteins.
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Affiliation(s)
- Alexandros Makriyannis
- Center for Drug Discovery and Department of Pharmaceutical Sciences and Chemistry, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, United States.
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Conformation of nifedipine in hydrated 1,2-di-myristoyl-sn-glycero-3-phosphorylcholine bilayer molecular dynamics simulation. J Biosci 1997. [DOI: 10.1007/bf02704731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Ko YT, Ludescher RD, Frost DJ, Wasserman BP. Use of cilofungin as direct fluorescent probe for monitoring antifungal drug-membrane interaction. Antimicrob Agents Chemother 1994; 38:1378-85. [PMID: 8092841 PMCID: PMC188214 DOI: 10.1128/aac.38.6.1378] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Cilofungin is an antifungal cyclopeptide which inhibits cell wall (1,3)-beta-glucan biosynthesis in fungal organisms, and its action against Candida albicans (1,3)-beta-glucan synthase has been widely studied. Since glucan synthase inactivation is thought to partially result from perturbations of the membrane lipid environment, the interaction of cilofungin with fungal membranes and phosphatidylcholine membrane vesicles was studied. Cilofungin, which contains two independent aromatic groups, has an excitation maximum of 270 nm and an emission maximum of 317 nm in aqueous solution. Comparison of the fluorescence properties of cilofungin with those of the analogs pneumocandin B0, N-acetyl-tyrosinamide, and 4-hydroxybenzamide indicated that the emission of cilofungin largely derived from the p-octyloxybenzamide side chain. Microsomal membranes from Saccharomyces cerevisiae, C. albicans, and phosphatidylcholine membrane vesicles induced a blue shift in the cilofungin emission spectrum and increased the cilofungin steady-state emission anisotropy, providing direct evidence for a cilofungin-membrane interaction. Cilofungin interacted more strongly with membranes of C. albicans than with those of S. cerevisiae, correlating with previous findings that C. albicans is far more susceptible than S. cerevisiae to the action of cilofungin. These findings support the hypothesis that drug-induced inhibition of the (1,3)-beta-glucan synthesis results from the perturbation of the membrane environment and the interaction with the glucan synthase complex combined. The study demonstrated ways in which the fluorescence properties of drugs can be used to directly evaluate drug-membrane interactions and structure-activity relationships.
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Affiliation(s)
- Y T Ko
- Department of Food Science, Cook College, Rutgers University, New Brunswick, New Jersey 08903-023
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Takizawa S, Hogan MJ, Buchan AM, Hakim AM. In vivo binding of [3H]nimodipine in rat brain after transient forebrain ischemia. J Cereb Blood Flow Metab 1994; 14:397-405. [PMID: 8163582 DOI: 10.1038/jcbfm.1994.51] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We report the regional variation in relative in vivo binding of the L-type voltage sensitive calcium channel (VSCC) antagonist [3H]nimodipine to brain following transient forebrain ischemia in the rat. At 30-min of reperfusion after 20 min of forebrain ischemia, [3H]nimodipine binding was significantly increased in striatum, CA3 and CA4, and dentate relative to binding in sham-operated rats, suggesting that VSCCs were responding to ischemic depolarization. Two h following ischemia, binding in all brain structures returned to normal levels indicating repolarization of cell membranes. At 24 h of recirculation, increased [3H]nimodipine binding was again observed in striatum and dentate. Binding remained elevated in the striatum and dentate, and increased binding became evident in the CA1 region of the hippocampus after 48 h of reperfusion. With the exception of the dentate gyrus, the second rise in [3H]nimodipine binding anticipated or coincided with the observed regional ischemic cell changes. These observations in global cerebral ischemia support previous work indicating that in vivo binding of [3H]nimodipine to the L-type VSCC may be an early and sensitive indicator of impending ischemic injury. Such measurements may be of use in identifying vulnerable brain regions and defining a therapeutic window of opportunity in models of cerebral ischemia.
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Young HS, Skita V, Mason RP, Herbette LG. Molecular basis for the inhibition of 1,4-dihydropyridine calcium channel drugs binding to their receptors by a nonspecific site interaction mechanism. Biophys J 1992; 61:1244-55. [PMID: 1318093 PMCID: PMC1260388 DOI: 10.1016/s0006-3495(92)81933-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The "membrane bilayer" pathway (Rhodes, D. G., J. G. Sarmiento, and L. G. Herbette. 1985. Mol. Pharmacol. 27:612-623.) for 1,4-dihydropyridine calcium channel drug (DHP) binding to receptor sites in cardiac sarcolemmal membranes has been extended to include the interaction of amphiphiles within the lipid bilayer. These studies focused on the ability of the Class III antiarrhythmic agents bretylium and clofilium to nonspecifically inhibit DHP-receptor binding in canine cardiac sarcolemma. Clofilium was found to inhibit nimodipine binding with an inhibition constant of approximately 5 microM, whereas bretylium had no effect on nimodipine binding. Small angle x-ray diffraction was then used to examine the differential ability of these two Class III agents to inhibit DHP-receptor binding. The time-averaged locations of bretylium, clofilium, and nimodipine in bovine cardiac phosphatidylcholine (BCPC) bilayers (supplemented with 13 mol% cholesterol) were determined to a resolution of 9 A. The location of bretylium as dominated by its phenyl ring in BCPC bilayers was found to be at the hydrocarbon core/water interface, similar to that of the dihydropyridine ring of nimodipine. The location of clofilium as dominated by its phenyl ring was found to be below the hydrocarbon/core water interface within the hydrocarbon chain region of the bilayer, similar to that of the phenyl ring of nimodipine. The location of the dihydropyridine ring portion of nimodipine has previously been shown by neutron diffraction to be located at the hydrocarbon core/water interface of native sarcoplasmic reticulum, consistent with the small angle x-ray data from model membranes in this paper. Therefore, we speculate that the nonspecific inhibition arises from the interaction of clofilium's phenyl ring with the site on the calcium channel receptor where the phenyl ring portion of nimodipine must interact. The DHP-receptor binding pathway would then involve both nonspecific (membrane) and specific (protein) binding components, both of which are necessary for receptor binding.
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Affiliation(s)
- H S Young
- Department of Biochemistry, University of Connecticut, Farmington 06030-2017
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