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Vashchenko OV, Ye Brodskii R, Davydova IO, Vashchenko PV, Ivaniuk OI, Ruban OA. Biopharmaceutical studies of a novel sedative sublingual lozenge based on glycine and tryptophan: A rationale for mucoadhesive agent selection. Eur J Pharm Biopharm 2024:114469. [PMID: 39186958 DOI: 10.1016/j.ejpb.2024.114469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 08/10/2024] [Accepted: 08/19/2024] [Indexed: 08/28/2024]
Abstract
Effective sedative drugs are in great demand due to increasing incidence of nervous disorders. The present work was aimed to develop a novel sublingual sedative drug based on glycine and L-tryptophan amino acids. Carbopol and different hydroxypropyl methylcellulose species were alternatively tested as mucoadhesive agents intended to prolong tryptophan sublingual release time. A model lipid medium of fully hydrated L-α-dimyristoylphosphatidylcholine was used for optimal mucoadhesive agents selection. Simultaneous processes of drug release and diffusion in lipid medium were first investigated involving both experimental and theoretical approaches. Individual substances, their selected combinations as well as different drug formulations were consecutively examined. Application of kinetic differential scanning calorimetry method allowed us to reveal a number of specific drug-excipient effects. Lactose was found to essentially facilitate tryptophan release and provide its ability to get into the bloodstream simultaneously with glycine, which is necessary to achieve glycine-tryptophan synergism. Introduction of a mucoadhesive agent into the formulation was shown to change kinetics of drug-membrane interactions variously depending on viscosity grade. Among the mucoadhesive agents, hydroxypropyl methylcellulose species K4M and E4M were shown to further accelerate drug release, therefore they were selected as optimal. Thus, effectiveness of the novel sedative drug was provided by including some excipients, such as lactose and the selected mucoadhesive agent species. A dynamic mathematical model was developed properly describing release and diffusion in lipid medium of various drug substances. Our study clearly showed applicability of a lipid medium to meet challenges such as drug-excipient interactions and optimization of drug formulations.
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Affiliation(s)
- O V Vashchenko
- Institute for Scintillation Materials, National Academy of Science of Ukraine, 60 Nauky Ave., 61072 Kharkov, Ukraine.
| | - R Ye Brodskii
- Institute for Single Crystals, National Academy of Science of Ukraine, 60 Nauky Ave, 61072 Kharkiv, Ukraine
| | - I O Davydova
- National University of Pharmacy, 53 H. Skovorody Str., 61002 Kharkiv, Ukraine
| | - P V Vashchenko
- Institute for Scintillation Materials, National Academy of Science of Ukraine, 60 Nauky Ave., 61072 Kharkov, Ukraine
| | - O I Ivaniuk
- National University of Pharmacy, 53 H. Skovorody Str., 61002 Kharkiv, Ukraine
| | - O A Ruban
- National University of Pharmacy, 53 H. Skovorody Str., 61002 Kharkiv, Ukraine
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2
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Wu WW, Choe M, Johannesen L, Vicente J, Bende G, Stockbridge NL, Strauss DG, Garnett C. ICH S7B In Vitro Assays Do Not Address Mechanisms of QT C Prolongation for Peptides and Proteins - Data in Support of Not Needing Dedicated QT C Studies. Clin Pharmacol Ther 2023; 114:1332-1341. [PMID: 37702218 DOI: 10.1002/cpt.3047] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 08/29/2023] [Indexed: 09/14/2023]
Abstract
Current cardiac safety testing focuses on detecting drug-induced QTC prolongation as a surrogate for risk of Torsade de Pointes. The nonclinical strategy, described in International Conference on Harmonization (ICH) S7B, includes in vitro assessment of hERG block or ventricular repolarization delay and in vivo QT prolongation. Several studies have reported predictive values of ICH S7B results for clinical QTC outcomes for small molecules; none has examined peptides and proteins other than monoclonal antibodies. To address this knowledge gap, information for peptides and proteins submitted to the US Food and Drug Administration (FDA) was collected. Results of hERG assays, ventricular repolarization assays, and in vivo QT assessment were compared with clinical QTC study outcomes. The results show that 14% clinical QTC studies for approved and investigational products failed to exclude 10-ms QTC prolongation. Clinical QTC prolongation for these molecules lacked concentration-dependence which is expected for hERG block-mediated mechanism or QTC prolongation could not be excluded due to characterization in the clinical study. The hERG and ventricular repolarization assays do not identify clinical QTC prolongation potential for peptides and proteins. Lack of alignment between hERG and ventricular repolarization assay results and clinical QTC outcomes suggests that the mechanisms of QTC prolongation by some peptides and proteins are unrelated to direct cardiac ion channel block. Similar to large targeted proteins and monoclonal antibodies, peptides and proteins regardless of size have a low likelihood of direct cardiac ion channel interactions. This characteristic supports waiving the requirement for thorough QT assessment for products comprised of naturally occurring amino acids unless proarrhythmia potential is suggested by nonclinical or clinical data.
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Affiliation(s)
- Wendy W Wu
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Science, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Moran Choe
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Science, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
- Division of Hematology, Oncology, Toxicology, Office of Oncologic Diseases, Office of New Drugs, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Lars Johannesen
- Division of Cardiology and Nephrology, Office of Cardiology, Hematology, Endocrinology and Nephrology, Office of New Drugs, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Jose Vicente
- Division of Cardiology and Nephrology, Office of Cardiology, Hematology, Endocrinology and Nephrology, Office of New Drugs, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Girish Bende
- Division of Cardiometabolic and Endocrine Pharmacology, Office of Clinical Pharmacology, Office of Translational Science, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
- Takeda Pharmaceutical Company Limited, Cambridge, Massachusetts, USA
| | - Norman L Stockbridge
- Division of Cardiology and Nephrology, Office of Cardiology, Hematology, Endocrinology and Nephrology, Office of New Drugs, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - David G Strauss
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Science, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Christine Garnett
- Division of Cardiology and Nephrology, Office of Cardiology, Hematology, Endocrinology and Nephrology, Office of New Drugs, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
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3
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Abstract
The metabolism of a bacterial cell stretches beyond its boundaries, often connecting with the metabolism of other cells to form extended metabolic networks that stretch across communities, and even the globe. Among the least intuitive metabolic connections are those involving cross-feeding of canonically intracellular metabolites. How and why are these intracellular metabolites externalized? Are bacteria simply leaky? Here I consider what it means for a bacterium to be leaky, and I review mechanisms of metabolite externalization from the context of cross-feeding. Despite common claims, diffusion of most intracellular metabolites across a membrane is unlikely. Instead, passive and active transporters are likely involved, possibly purging excess metabolites as part of homeostasis. Re-acquisition of metabolites by a producer limits the opportunities for cross-feeding. However, a competitive recipient can stimulate metabolite externalization and initiate a positive-feedback loop of reciprocal cross-feeding.
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Affiliation(s)
- James B McKinlay
- Department of Biology, Indiana University, Bloomington, Indiana, USA;
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4
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Li Y, Jiang G, Long H, Liao Y, Wu L, Huang W, Liu X. Contribution of trehalose to ethanol stress tolerance of Wickerhamomyces anomalus. BMC Microbiol 2023; 23:239. [PMID: 37644381 PMCID: PMC10463620 DOI: 10.1186/s12866-023-02982-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 08/16/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND The ascomycetous heterothallic yeast Wickerhamomyces anomalus (WA) has received considerable attention and has been widely reported in the winemaking industry for its distinctive physiological traits and metabolic attributes. An increased concentration of ethanol during ethanol fermentation, however, causes ethanol stress (ES) on the yeast cells. Trehalose has been implicated in improving survival under various stress conditions in microorganisms. Herein, we determined the effects of trehalose supplementation on the survival, differentially expressed genes (DEGs), cellular morphology, and oxidative stress tolerance of WA in response to ES. RESULTS The results indicated that trehalose improved the survival and anomalous surface and ultrastructural morphology of WA. Additionally, trehalose improved redox homeostasis by reducing the levels of reactive oxygen species (ROS) and inducing the activities of antioxidant enzymes. In addition, DEGs affected by the application of trehalose were enriched in these categories including in gene expression, protein synthesis, energy metabolism, and cell cycle pathways. Additionally, trehalose increased the content of intracellular malondialdehyde (MDA) and adenosine triphosphate. CONCLUSIONS These results reveal the protective role of trehalose in ES mitigation and strengthen the possible uses of WA in the wine fermentation sector.
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Affiliation(s)
- Yinfeng Li
- Guizhou Institute of Technology, Guiyang, 550000, People's Republic of China
| | - Guilan Jiang
- Guizhou Institute of Technology, Guiyang, 550000, People's Republic of China
| | - Hua Long
- Guizhou Institute of Technology, Guiyang, 550000, People's Republic of China
| | - Yifa Liao
- Guizhou Institute of Technology, Guiyang, 550000, People's Republic of China
| | - Liuliu Wu
- Henan Institute of Science and Technology, Xinxiang, 453000, People's Republic of China
| | - Wenyue Huang
- Guizhou Institute of Technology, Guiyang, 550000, People's Republic of China
| | - Xiaozhu Liu
- Guizhou Institute of Technology, Guiyang, 550000, People's Republic of China.
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5
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Duncan KM, Trousdale RC, Gonzales CN, Steel WH, Walker RA. l-Phenylalanine Partitioning Mechanisms in Model Biological Membranes. J Phys Chem B 2023. [PMID: 37315336 DOI: 10.1021/acs.jpcb.2c08582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Time-resolved fluorescence spectroscopy in combination with differential scanning calorimetry (DSC) was used to study the chemical interactions that occur when l-phenylalanine is introduced to solutions containing phosphatidylcholine vesicles. Studies reported in this work address open questions about l-Phe's affinity for lipid vesicle bilayers, the effects of l-Phe partitioning on bilayer properties, l-Phe's solvation within a lipid bilayer, and the amount of l-Phe within that local solvation environment. DSC data show that l-Phe reduces the amount of heat necessary to melt saturated phosphatidylcholine bilayers from their gel to liquid-crystalline state but does not change the transition temperature (Tgel-lc). Time-resolved emission shows only a single l-Phe lifetime at low temperatures corresponding to l-Phe remaining solvated in aqueous solution. At temperatures close to Tgel-lc, a second, shorter lifetime appears that is assigned to l-Phe already embedded within the membrane that becomes hydrated as water starts to permeate the lipid bilayer. This new lifetime is attributed to a conformationally restricted rotamer in the bilayer's polar headgroup region and accounts for up to 30% of the emission amplitude. Results reported for dipalmitoylphosphatidylcholine (DPPC, 16:0) lipid vesicles prove to be general, with similar effects observed for dimyristoylphosphatidylcholine (DMPC, 14:0) and distearoylphosphatidylcholine (DSPC, 18:0) vesicles. Taken together, these results create a complete and compelling picture of how l-Phe associates with model biological membranes. Furthermore, this approach to examining amino acid partitioning into membranes and the resulting solvation forces points to new strategies for studying the structure and chemistry of membrane-soluble peptides and selected membrane proteins.
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Affiliation(s)
- Katelyn M Duncan
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Rhys C Trousdale
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Cristina N Gonzales
- Department of Chemistry, Reed College, Portland, Oregon 97202, United States
| | - William H Steel
- Department of Chemistry, York College of Pennsylvania, York, Pennsylvania 17403, United States
| | - Robert A Walker
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
- Montana Materials Science Program, Montana State University, Bozeman, Montana 59717, United States
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6
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Kohara J, Bai L, Takeshima SN, Matsumoto Y, Hirai T, Aida Y. Correlation between the Biodistribution of Bovine Leukemia Virus in the Organs and the Proviral Load in the Peripheral Blood during Early Stages of Experimentally Infected Cattle. Pathogens 2023; 12:pathogens12010130. [PMID: 36678478 PMCID: PMC9867250 DOI: 10.3390/pathogens12010130] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 12/27/2022] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
Bovine leukemia virus (BLV) is the etiological agent of enzootic bovine leukosis. However, the propagation and distribution of BLV after primary infection still need to be fully elucidated. Here, we experimentally infected seven cattle with BLV and analyzed the BLV proviral load (PVL) in the blood and various organs. BLV was first detected in the blood of the cattle after one week, and the blood PVL increased for three weeks after infection. The PVL was maintained at a high level in five cattle, while it decreased to a low or medium level in two cattle. BLV was distributed in various organs, such as the heart, lung, liver, kidney, abomasum, and thymus, and, notably, in the spleen and lymph nodes. In cattle with a high blood PVL, BLV was detected in organs other than the spleen and lymph nodes, whereas in those with a low blood PVL, BLV was only detected in the spleen and lymph nodes. The amount of BLV in the organs was comparable to that in the blood. Our findings point to the possibility of estimating the distribution of BLV provirus in organs, lymph nodes, and body fluids by measuring the blood PVL, as it was positively correlated with the biodistribution of BLV provirus in the body of BLV infection during early stages.
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Affiliation(s)
- Junko Kohara
- Animal Health Group, Animal Research Center, Hokkaido Research Organization, Shintoku 081-0038, Japan
- Correspondence: (J.K.); (Y.A.)
| | - Lanlan Bai
- Virus Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan
- Graduate School of Science and Engineering, Iwate University, Morioka 020-8551, Japan
| | - Shin-nosuke Takeshima
- Virus Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan
- Department of Food and Nutrition, Jumonji University, 2-1-28 Sugasawa, Niiza 352-8510, Japan
| | - Yuki Matsumoto
- Virus Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan
| | - Tsunao Hirai
- Animal Health Group, Animal Research Center, Hokkaido Research Organization, Shintoku 081-0038, Japan
| | - Yoko Aida
- Virus Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan
- Laboratory of Global Infectious Diseases Control Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
- Correspondence: (J.K.); (Y.A.)
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7
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Maslowska-Jarzyna K, Bąk KM, Zawada B, Chmielewski MJ. pH-Dependent transport of amino acids across lipid bilayers by simple monotopic anion carriers. Chem Sci 2022; 13:12374-12381. [PMID: 36382290 PMCID: PMC9629080 DOI: 10.1039/d2sc04346g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 10/04/2022] [Indexed: 11/07/2023] Open
Abstract
The transport of amino acids across lipid membranes is vital for the proper functioning of every living cell. In spite of that, examples of synthetic transporters that can facilitate amino acid transport are rare. This is mainly because at physiological conditions amino acids predominantly exist as highly polar zwitterions and proper shielding of their charged termini, which is necessary for fast diffusion across lipophilic membranes, requires complex and synthetically challenging heteroditopic receptors. Here we report the first simple monotopic anion receptor, dithioamide 1, that efficiently transports a variety of natural amino acids across lipid bilayers at physiological pH. Mechanistic studies revealed that the receptor rapidly transports deprotonated amino acids, even though at pH 7.4 these forms account for less than 3% of the total amino acid concentration. We also describe a new fluorescent assay for the selective measurement of the transport of deprotonated amino acids into liposomes. The new assay allowed us to study the pH-dependence of amino acid transport and elucidate the mechanism of transport by 1, as well as to explain its exceptionally high activity. With the newly developed assay we screened also four other representative examples of monotopic anion transporters, of which two showed promising activity. Our results imply that heteroditopic receptors are not necessary for achieving high amino acid transport activities and that many of the previously reported anionophores might be active amino acid transporters. Based on these findings, we propose a new strategy for the development of artificial amino acid transporters with improved properties.
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Affiliation(s)
- Krystyna Maslowska-Jarzyna
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw Żwirki i Wigury 101 Warsaw 02-089 Poland
| | - Krzysztof M Bąk
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw Żwirki i Wigury 101 Warsaw 02-089 Poland
| | - Bartłomiej Zawada
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw Żwirki i Wigury 101 Warsaw 02-089 Poland
| | - Michał J Chmielewski
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw Żwirki i Wigury 101 Warsaw 02-089 Poland
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8
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Povilaitis SC, Fathizadeh A, Kogan M, Elber R, Webb LJ. Design of Peptides for Membrane Insertion: The Critical Role of Charge Separation. J Phys Chem B 2022; 126:6454-6463. [PMID: 35997537 PMCID: PMC9541189 DOI: 10.1021/acs.jpcb.2c04615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A physical understanding of membrane permeation and translocation by small, positively charged molecules can illuminate cell penetrating peptide mechanisms of entry and inform drug design. We have previously investigated the permeation of the doubly charged peptide WKW and proposed a defect-assisted permeation mechanism where a small molecule with +2 charge can achieve a metastable state spanning the bilayer by forming a membrane defect with charges stabilized by phospholipid phosphate groups. Here, we investigate the membrane permeation of two doubly charged peptides, WWK and WWWK, with charges separated by different lengths. Through complementary experiments and molecular dynamics simulations, we show that membrane permeation was an order of magnitude more favorable when charges were separated by an ∼2-3 Å greater distance on WWWK compared to WWK. These results agree with the previously proposed defect-assisted permeation mechanism, where a greater distance between positive charges would require a less extreme membrane defect to stabilize the membrane-spanning metastable state. We discuss the implications of these results in understanding the membrane permeation of cell-penetrating peptides and other small, positively charged membrane permeants.
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Affiliation(s)
- Sydney C. Povilaitis
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, United States
| | - Arman Fathizadeh
- Oden Institute for Computational Engineering and Science, University of Texas at Austin, Austin, Texas 78712, United States
| | - Molly Kogan
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, United States
| | - Ron Elber
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, United States
- Oden Institute for Computational Engineering and Science, University of Texas at Austin, Austin, Texas 78712, United States
| | - Lauren J. Webb
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, United States
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9
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Bioactivities of In Vitro Transepithelial Transported Peptides from Cooked Chicken Breast. Int J Pept Res Ther 2021. [DOI: 10.1007/s10989-021-10326-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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10
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Bailey TL, Hernandez-Fernaud JR, Gibson MI. Proline pre-conditioning of cell monolayers increases post-thaw recovery and viability by distinct mechanisms to other osmolytes. RSC Med Chem 2021; 12:982-993. [PMID: 34223163 PMCID: PMC8221256 DOI: 10.1039/d1md00078k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cell cryopreservation is an essential tool for drug toxicity/function screening and transporting cell-based therapies, and is essential in most areas of biotechnology. There is a challenge, however, associated with the cryopreservation of cells in monolayer format (attached to tissue culture substrates) which gives far lower cell yields (<20% typically) compared to suspension freezing. Here we investigate the mechanisms by which the protective osmolyte l-proline enhances cell-monolayer cryopreservation. Pre-incubating A549 cells with proline, prior to cryopreservation in monolayers, increased post-thaw cell yields two-fold, and the recovered cells grow faster compared to cells cryopreserved using DMSO alone. Further increases in yield were achieved by adding polymeric ice recrystallization inhibitors, which gave limited benefit in the absence of proline. Mechanistic studies demonstrated a biochemical, rather than biophysical (i.e. not affecting ice growth) mode of action. It was observed that incubating cells with proline (before freezing) transiently reduced the growth rate of the cells, which was not seen with other osmolytes (betaine and alanine). Removal of proline led to rapid growth recovery, suggesting that proline pre-conditions the cells for cold stress, but with no impact on downstream cell function. Whole cell proteomics did not reveal a single pathway or protein target but rather cells appeared to be primed for a stress response in multiple directions, which together prepare the cells for freezing. These results support the use of proline alongside standard conditions to improve post-thaw recovery of cell monolayers, which is currently considered impractical. It also demonstrates that a chemical biology approach to discovering small molecule biochemical modulators of cryopreservation may be possible, to be used alongside traditional (solvent) based cryoprotectants. Cell cryopreservation is an essential tool for transporting cell-based therapies, and is essential in most areas of biotechnology. Here proline pre-incubation prior to cell monolayer cryopreservation is explored, increasing post-thaw yields.![]()
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Affiliation(s)
- Trisha L Bailey
- Department of Chemistry, University of Warwick Gibbet Hill Road Coventry CV4 7AL UK
| | | | - Matthew I Gibson
- Department of Chemistry, University of Warwick Gibbet Hill Road Coventry CV4 7AL UK .,Warwick Medical School, University of Warwick Gibbet Hill Road Coventry CV4 7AL UK
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11
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Neunert G, Tomaszewska-Gras J, Baj A, Gauza-Włodarczyk M, Witkowski S, Polewski K. Phase Transitions and Structural Changes in DPPC Liposomes Induced by a 1-Carba-Alpha-Tocopherol Analogue. Molecules 2021; 26:2851. [PMID: 34064897 PMCID: PMC8151464 DOI: 10.3390/molecules26102851] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/22/2021] [Accepted: 05/04/2021] [Indexed: 11/26/2022] Open
Abstract
Steady-state emission spectroscopy of 1-anilino-8- naphthalene sulfonate (ANS) and 1,6-diphenyl-1,3,5-hexatriene (DPH), fluorescence anisotropy, and DSC methods were used to characterize the interactions of the newly synthesized 1-carba-alpha-tocopherol (CT) with a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) membrane. The DSC results showed significant perturbations in the DPPC structure for CT concentrations as low as 2 mol%. The main phase transition peak was broadened and shifted to lower temperatures in a concentration-dependent manner, and pretransition was abolished. Increasing CT concentrations induced the formation of new phases in the DPPC structure, leading to melting at lower temperatures and, finally, disruption of the ordered DPPC structure. Hydration and structural changes of the DPPC liposomes using ANS and DPH fluorescent probes, which are selectively located at different places in the bilayer, were studied. With the increased concentration of CT molecules in the DPPC liposomes, structural changes with the simultaneous formation of different phases of such mixture were observed. Temperature studies of such mixtures revealed a decrease in the temperature of the main phase transition and fluidization at decreasing temperatures related to increasing hydration in the bilayer. Contour plots obtained from concentration-temperature data with fluorescent probes allowed for identification of different phases, such as gel, ordered liquid, disordered liquid, and liquid crystalline phases. The CT molecule with a modified chromanol ring embedded in the bilayer led to H-bonding interactions, expelling water molecules from the interphase, thus introducing disorder and structural changes to the highly ordered gel phase.
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Affiliation(s)
- Grażyna Neunert
- Department of Physics and Biophysics, Faculty of Food Science and Nutrition, Poznan University of Life Sciences, Wojska Polskiego 38/42, 60-637 Poznan, Poland;
| | - Jolanta Tomaszewska-Gras
- Department of Food Quality and Safety Management, Faculty of Food Science and Nutrition, Poznan University of Life Sciences, Wojska Polskiego 31/33, 60-637 Poznan, Poland;
| | - Aneta Baj
- Department of Organic Chemistry, Faculty of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok, Poland; (A.B.); (S.W.)
| | - Marlena Gauza-Włodarczyk
- Department of Biophysics, Faculty of Medical Sciences, Poznan University of Medical Sciences, Grunwaldzka 6, 60-780 Poznan, Poland;
| | - Stanislaw Witkowski
- Department of Organic Chemistry, Faculty of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok, Poland; (A.B.); (S.W.)
| | - Krzysztof Polewski
- Department of Physics and Biophysics, Faculty of Food Science and Nutrition, Poznan University of Life Sciences, Wojska Polskiego 38/42, 60-637 Poznan, Poland;
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12
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Labourel F, Rajon E. Resource uptake and the evolution of moderately efficient enzymes. Mol Biol Evol 2021; 38:3938-3952. [PMID: 33964160 PMCID: PMC8382906 DOI: 10.1093/molbev/msab132] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Enzymes speed up reactions that would otherwise be too slow to sustain the metabolism of selfreplicators. Yet, most enzymes seem only moderately efficient, exhibiting kinetic parameters orders of magnitude lower than their expected physically achievable maxima and spanning over surprisingly large ranges of values. Here, we question how these parameters evolve using a mechanistic model where enzyme efficiency is a key component of individual competition for resources. We show that kinetic parameters are under strong directional selection only up to a point, above which enzymes appear to evolve under near-neutrality, thereby confirming the qualitative observation of other modeling approaches. While the existence of a large fitness plateau could potentially explain the extensive variation in enzyme features reported, we show using a population genetics model that such a widespread distribution is an unlikely outcome of evolution on a common landscape, as mutation–selection–drift balance occupy a narrow area even when very moderate biases towards lower efficiency are considered. Instead, differences in the evolutionary context encountered by each enzyme should be involved, such that each evolves on an individual, unique landscape. Our results point to drift and effective population size playing an important role, along with the kinetics of nutrient transporters, the tolerance to high concentrations of intermediate metabolites, and the reversibility of reactions. Enzyme concentration also shapes selection on kinetic parameters, but we show that the joint evolution of concentration and efficiency does not yield extensive variance in evolutionary outcomes when documented costs to protein expression are applied.
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Affiliation(s)
- Florian Labourel
- Univ Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR5558, Villeurbanne, F-69622, France
| | - Etienne Rajon
- Univ Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR5558, Villeurbanne, F-69622, France
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13
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Nilam M, Collin S, Karmacharya S, Hennig A, Nau WM. Membrane Permeability and Its Activation Energies in Dependence on Analyte, Lipid, and Phase Type Obtained by the Fluorescent Artificial Receptor Membrane Assay. ACS Sens 2021; 6:175-182. [PMID: 33347764 DOI: 10.1021/acssensors.0c02064] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Time-resolved monitoring of the permeability of analytes is of utmost importance in membrane research. Existing methods are restricted to single-point determinations or flat synthetic membranes, limiting access to biologically relevant kinetic parameters (permeation rate constant, permeation coefficients). We now use the recently introduced fluorescent artificial receptor membrane assay (FARMA) as a method to monitor, in real time, the permeation of indole derivatives through liposomal membranes of different lipid compositions. This method is based on the liposomal encapsulation of a chemosensing ensemble or "fluorescent artificial receptor", consisting of 2,7-dimethyldiazapyrenium as a fluorescent dye and cucurbit[8]uril as the macrocyclic receptor, that responds to the complexation of a permeating aromatic analyte by fluorescence quenching. FARMA does not require a fluorescent labeling of the analytes and allows access to permeability coefficients in the range from 10-8 to 10-4 cm s-1. The effect of temperature on the permeation rate of a series of indole derivatives across the phospholipid membranes was studied. The activation energies for permeation through POPC/POPS phospholipid membranes were in the range of 28-96 kJ mol-1. To study the effect of different lipid phases on the membrane permeability, we performed experiments with DPPC/DOPS vesicles, which showed a phase transition from a gel phase to a liquid-crystalline phase, where the activation energies for the permeation process were expected to show a dramatic change. Accordingly, for the permeation of the indole derivatives into the DPPC/DOPS liposomes, discontinuities were observed in the Arrhenius plots, from which the permeation activation energies for the distinct phases could be determined, for example, for tryptamine 245 kJ mol-1 in the gel phase and 47 kJ mol-1 in the liquid-crystalline phase.
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Affiliation(s)
- Mohamed Nilam
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
- Institute for Chemistry of New Materials, University of Osnabrück, Barbarastraße 7, 49069 Osnabrück, Germany
| | - Solène Collin
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Shreya Karmacharya
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Andreas Hennig
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
- Institute for Chemistry of New Materials, University of Osnabrück, Barbarastraße 7, 49069 Osnabrück, Germany
| | - Werner M. Nau
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
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14
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Cockram PE, Dickie EA, Barrett MP, Smith TK. Halogenated tryptophan derivatives disrupt essential transamination mechanisms in bloodstream form Trypanosoma brucei. PLoS Negl Trop Dis 2020; 14:e0008928. [PMID: 33275612 PMCID: PMC7744056 DOI: 10.1371/journal.pntd.0008928] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 12/16/2020] [Accepted: 10/19/2020] [Indexed: 12/05/2022] Open
Abstract
Amino acid metabolism within Trypanosoma brucei, the causative agent of human African trypanosomiasis, is critical for parasite survival and virulence. Of these metabolic processes, the transamination of aromatic amino acids is one of the most important. In this study, a series of halogenated tryptophan analogues were investigated for their anti-parasitic potency. Several of these analogues showed significant trypanocidal activity. Metabolomics analysis of compound-treated parasites revealed key differences occurring within aromatic amino acid metabolism, particularly within the widely reported and essential transamination processes of this parasite.
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Affiliation(s)
- Peter E. Cockram
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Emily A. Dickie
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Michael P. Barrett
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Terry K. Smith
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, Scotland
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15
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Chen J, Hackett EP, Singh J, Kovács Z, Park JM. Simultaneous Assessment of Intracellular and Extracellular pH Using Hyperpolarized [1- 13C]Alanine Ethyl Ester. Anal Chem 2020; 92:11681-11686. [PMID: 32786486 DOI: 10.1021/acs.analchem.0c01568] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Tissue pH is tightly regulated in vivo, being a sensitive physiological biomarker. Advent of dissolution dynamic nuclear polarization (DNP) and its translation to humans stimulated development of pH-sensitive agents. However, requirements of DNP probes such as biocompatibility, signal sensitivity, and spin-lattice relaxation time (T1) complicate in vivo translation of the agents. Here, we developed a 13C-labeled alanine derivative, [1-13C]-l-alanine ethyl ester, as a viable DNP probe whose chemical shift is sensitive to the physiological pH range, and demonstrated the feasibility in phantoms and rat livers in vivo. Alanine ethyl ester readily crosses cell membrane while simultaneously assessing extracellular and intracellular pH in vivo. Following cell transport, [1-13C]-l-alanine ethyl ester is instantaneously hydrolyzed to [1-13C]-l-alanine, and subsequently metabolized to [1-13C]lactate and [13C]bicarbonate. The pH-insensitive alanine resonance was used as a reference.
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Affiliation(s)
- Jun Chen
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8568, United States
| | - Edward P Hackett
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8568, United States
| | - Jaspal Singh
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8568, United States
| | - Zoltán Kovács
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8568, United States
| | - Jae Mo Park
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8568, United States.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8568, United States.,Department of Electrical and Computer Engineering, University of Texas at Dallas, Richardson, Texas 75080, United States
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16
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Frączek K, Ferraiolo M, Hermans E, Bujalska-Zadrozny M, Kasarello K, Erdei A, Kulik K, Kowalczyk A, Wojciechowski P, Sulejczak D, Sosnowski P, Granica S, Benyhe S, Kaczynska K, Nagraba L, Stolarczyk A, Cudnoch-Jedrzejewska A, Kleczkowska P. Novel opioid-neurotensin-based hybrid peptide with spinal long-lasting antinociceptive activity and a propensity to delay tolerance development. Acta Pharm Sin B 2020; 10:1440-1452. [PMID: 32963942 PMCID: PMC7488486 DOI: 10.1016/j.apsb.2020.04.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 03/01/2020] [Accepted: 04/20/2020] [Indexed: 01/04/2023] Open
Abstract
The behavioral responses exerted by spinal administration of the opioid-neurotensin hybrid peptide, PK23, were studied in adult male rats. The antinociceptive effect upon exposure to a thermal stimulus, as well as tolerance development, was assessed in an acute pain model. The PK23 chimera at a dose of 10 nmol/rat produced a potent pain-relieving effect, especially after its intrathecal administration. Compared with intrathecal morphine, this novel compound was found to possess a favourable side effect profile characterized by a reduced scratch reflex, delayed development of analgesic tolerance or an absence of motor impairments when given in the same manner, though some animals died following barrel rotation as a result of its i.c.v. administration (in particular at doses higher than 10 nmol/rat). Nonetheless, these results suggest the potential use of hybrid compounds encompassing both opioid and neurotensin structural fragments in pain management. This highlights the enormous potential of synthetic neurotensin analogues as promising future analgesics.
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17
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Biedermann F, Ghale G, Hennig A, Nau WM. Fluorescent artificial receptor-based membrane assay (FARMA) for spatiotemporally resolved monitoring of biomembrane permeability. Commun Biol 2020; 3:383. [PMID: 32669621 PMCID: PMC7363885 DOI: 10.1038/s42003-020-1108-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 06/19/2020] [Indexed: 02/07/2023] Open
Abstract
The spatiotemporally resolved monitoring of membrane translocation, e.g., of drugs or toxins, has been a long-standing goal. Herein, we introduce the fluorescent artificial receptor-based membrane assay (FARMA), a facile, label-free method. With FARMA, the permeation of more than hundred organic compounds (drugs, toxins, pesticides, neurotransmitters, peptides, etc.) through vesicular phospholipid bilayer membranes has been monitored in real time (µs-h time scale) and with high sensitivity (nM-µM concentration), affording permeability coefficients across an exceptionally large range from 10-9-10-3 cm s-1. From a fundamental point of view, FARMA constitutes a powerful tool to assess structure-permeability relationships and to test biophysical models for membrane passage. From an applied perspective, FARMA can be extended to high-throughput screening by adaption of the microplate reader format, to spatial monitoring of membrane permeation by microscopy imaging, and to the compartmentalized monitoring of enzymatic activity.
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Affiliation(s)
- Frank Biedermann
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany.
| | - Garima Ghale
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany
| | - Andreas Hennig
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany
| | - Werner M Nau
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany.
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18
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Churchill GC, Strupp M, Galione A, Platt FM. Unexpected differences in the pharmacokinetics of N-acetyl-DL-leucine enantiomers after oral dosing and their clinical relevance. PLoS One 2020; 15:e0229585. [PMID: 32108176 PMCID: PMC7046201 DOI: 10.1371/journal.pone.0229585] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 02/11/2020] [Indexed: 12/18/2022] Open
Abstract
The enantiomers of many chiral drugs not only exhibit different pharmacological effects in regard to targets that dictate therapeutic and toxic effects, but are also handled differently in the body due to pharmacokinetic effects. We investigated the pharmacokinetics of the enantiomers of N-acetyl-leucine after administration of the racemate (N-acetyl-DL-leucine) or purified, pharmacologically active L-enantiomer (N-acetyl-L-leucine). The results suggest that during chronic administration of the racemate, the D-enantiomer would accumulate, which could have negative effects. Compounds were administered orally to mice. Plasma and tissue samples were collected at predetermined time points (0.25 to 8 h), quantified with liquid chromatography/mass spectrometry, and pharmacokinetic constants were calculated using a noncompartmental model. When administered as the racemate, both the maximum plasma concentration (Cmax) and the area under the plasma drug concentration over time curve (AUC) were much greater for the D-enantiomer relative to the L-enantiomer. When administered as the L-enantiomer, the dose proportionality was greater than unity compared to the racemate, suggesting saturable processes affecting uptake and/or metabolism. Elimination (ke and T1/2) was similar for both enantiomers. These results are most readily explained by inhibition of uptake at an intestinal carrier of the L-enantiomer by the D-enantiomer, and by first-pass metabolism of the L-, but not D-enantiomer, likely by deacetylation. In brain and muscle, N-acetyl-L-leucine levels were lower than N-acetyl-D-leucine, consistent with rapid conversion into L-leucine and utilization by normal leucine metabolism. In summary, the enantiomers of N-acetyl-leucine exhibit large, unexpected differences in pharmacokinetics due to both unique handling and/or inhibition of uptake and metabolism of the L-enantiomer by the D-enantiomer. Taken together, these results have clinical implications supporting the use of N-acetyl-L-leucine instead of the racemate or N-acetyl-D-leucine, and support the research and development of only N-acetyl-L-leucine.
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Affiliation(s)
- Grant C. Churchill
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Michael Strupp
- Department of Neurology, German Center for Vertigo and Balance Disorders, Ludwig Maximilians University Hospital Munich, Munich, Germany
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Frances M. Platt
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
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19
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Weidenfeld I, Zakian C, Duewell P, Chmyrov A, Klemm U, Aguirre J, Ntziachristos V, Stiel AC. Homogentisic acid-derived pigment as a biocompatible label for optoacoustic imaging of macrophages. Nat Commun 2019; 10:5056. [PMID: 31699983 PMCID: PMC6838096 DOI: 10.1038/s41467-019-13041-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 10/15/2019] [Indexed: 02/06/2023] Open
Abstract
Macrophages are one of the most functionally-diverse cell types with roles in innate immunity, homeostasis and disease making them attractive targets for diagnostics and therapy. Photo- or optoacoustics could provide non-invasive, deep tissue imaging with high resolution and allow to visualize the spatiotemporal distribution of macrophages in vivo. However, present macrophage labels focus on synthetic nanomaterials, frequently limiting their ability to combine both host cell viability and functionality with strong signal generation. Here, we present a homogentisic acid-derived pigment (HDP) for biocompatible intracellular labeling of macrophages with strong optoacoustic contrast efficient enough to resolve single cells against a strong blood background. We study pigment formation during macrophage differentiation and activation, and utilize this labeling method to track migration of pro-inflammatory macrophages in vivo with whole-body imaging. We expand the sparse palette of macrophage labels for in vivo optoacoustic imaging and facilitate research on macrophage functionality and behavior.
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Affiliation(s)
- Ina Weidenfeld
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
| | - Christian Zakian
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
- Chair of Biological Imaging, Technische Universität München, Munich, Germany
| | - Peter Duewell
- Institute of Innate Immunity, University of Bonn, Bonn, Germany
| | - Andriy Chmyrov
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
- Center for Translational Cancer Research (TranslaTUM), Technische Universität München, Munich, Germany
| | - Uwe Klemm
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
| | - Juan Aguirre
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
- Chair of Biological Imaging, Technische Universität München, Munich, Germany
| | - Vasilis Ntziachristos
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
- Chair of Biological Imaging, Technische Universität München, Munich, Germany
- Center for Translational Cancer Research (TranslaTUM), Technische Universität München, Munich, Germany
| | - Andre C Stiel
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany.
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20
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Jusková P, Schmid YRF, Stucki A, Schmitt S, Held M, Dittrich PS. "Basicles": Microbial Growth and Production Monitoring in Giant Lipid Vesicles. ACS APPLIED MATERIALS & INTERFACES 2019; 11:34698-34706. [PMID: 31454223 PMCID: PMC7462352 DOI: 10.1021/acsami.9b12169] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 08/27/2019] [Indexed: 05/03/2023]
Abstract
We present an optimized protocol to encapsulate bacteria inside giant unilamellar lipid vesicles combined with a microfluidic platform for real-time monitoring of microbial growth and production. The microfluidic device allows us to immobilize the lipid vesicles and record bacterial growth and production using automated microscopy. Moreover, the lipid vesicles retain hydrophilic molecules and therefore can be used to accumulate products of microbial biosynthesis, which we demonstrate here for a riboflavin-producing bacterial strain. We show that stimulation as well as inhibition of bacterial production can be performed through the liposomal membrane simply by passive diffusion of inducing or antibiotic compounds, respectively. The possibility to introduce as well as accumulate compounds in liposomal cultivation compartments represents great advantage over the current state of the art systems, emulsion droplets, and gel beads. Additionally, the encapsulation of bacteria and monitoring of individual lipid vesicles have been accomplished on a single microfluidic device. The presented system paves the way toward highly parallel microbial cultivation and monitoring as required in biotechnology, basic research, or drug discovery.
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Affiliation(s)
- Petra Jusková
- Department
of Biosystems Science and Engineering, Bioanalytics Group, and Department of
Biosystems Science and Engineering, Bioprocess Laboratory, ETH Zürich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Yannick R. F. Schmid
- Department
of Biosystems Science and Engineering, Bioanalytics Group, and Department of
Biosystems Science and Engineering, Bioprocess Laboratory, ETH Zürich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Ariane Stucki
- Department
of Biosystems Science and Engineering, Bioanalytics Group, and Department of
Biosystems Science and Engineering, Bioprocess Laboratory, ETH Zürich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Steven Schmitt
- Department
of Biosystems Science and Engineering, Bioanalytics Group, and Department of
Biosystems Science and Engineering, Bioprocess Laboratory, ETH Zürich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Martin Held
- Department
of Biosystems Science and Engineering, Bioanalytics Group, and Department of
Biosystems Science and Engineering, Bioprocess Laboratory, ETH Zürich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Petra S. Dittrich
- Department
of Biosystems Science and Engineering, Bioanalytics Group, and Department of
Biosystems Science and Engineering, Bioprocess Laboratory, ETH Zürich, Mattenstrasse 26, CH-4058 Basel, Switzerland
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21
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Cao Z, Zhang X, Wang C, Liu L, Zhao L, Wang J, Zhou Y. Different effects of cholesterol on membrane permeation of arginine and tryptophan revealed by bias-exchange metadynamics simulations. J Chem Phys 2019; 150:084106. [PMID: 30823753 DOI: 10.1063/1.5082351] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Experiments have shown that cholesterol influences the membrane permeability of small molecules, amino acids, and cell-penetrating peptides. However, their exact translocation mechanisms under the influence of cholesterol remain poorly understood. Given the practical importance of cell-penetrating peptides and the existence of varied cholesterol contents in different cell types, it is necessary to examine the permeation of amino acids in cholesterol-containing membranes at atomic level of details. Here, bias-exchange metadynamics simulations were employed to investigate the molecular mechanism of the membrane permeation of two amino acids Arg and Trp important for cell-penetrating peptides in the presence of different concentrations of cholesterol. We found that the free energy barrier of Arg+ (the protonated form) permeation increased linearly as the cholesterol concentration increased, whereas the barrier of Trp permeation had a rapid increase from 0 mol. % to 20 mol. % cholesterol-containing membranes and nearly unchanged from 20 mol. % to 40 mol. % cholesterol-containing membranes. Arg0 becomes slightly more stable than Arg+ at the center of the dipalmitoylphosphatidylcholine (DPPC) membrane with 40 mol. % cholesterol concentrations. As a result, Arg+ has a similar permeability as Trp at 0 mol. % and 20 mol. % cholesterol, but a significantly lower permeability than Trp at 40 mol. % cholesterol. This difference is caused by the gradual reduction of water defects for Arg+ as the cholesterol concentration increases but lack of water defects for Trp in cholesterol-containing membranes. Strong but different orientation dependence between Arg+ and Trp permeations is observed. These results provide an improved microscopic understanding of amino-acid permeation through cholesterol-containing DPPC membrane systems.
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Affiliation(s)
- Zanxia Cao
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China
| | - Xiumei Zhang
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China
| | - Chunling Wang
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China
| | - Lei Liu
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China
| | - Liling Zhao
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China
| | - Jihua Wang
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China
| | - Yaoqi Zhou
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China
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22
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Anderson CM, Cardenas A, Elber R, Webb LJ. Preferential Equilibrium Partitioning of Positively Charged Tryptophan into Phosphatidylcholine Bilayer Membranes. J Phys Chem B 2019; 123:170-179. [PMID: 30481465 PMCID: PMC6331081 DOI: 10.1021/acs.jpcb.8b09872] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/19/2018] [Indexed: 11/29/2022]
Abstract
The interactions between small molecules and lipid bilayers play a critical role in the function of cellular membranes. Understanding how a small molecule interacts with the lipid bilayer differently based on its charge reveals primordial mechanisms of transport across membranes and assists in the design of drug molecules that can penetrate cells. We have previously reported that tryptophan permeated through a phosphatidylcholine lipid bilayer membrane at a faster rate when it was positively charged (Trp+) than when negatively charged (Trp-), which corresponded to a lower potential of mean force (PMF) barrier determined through simulations. In this report, we demonstrate that Trp+ partitions into the lipid bilayer membrane to a greater degree than Trp- by interacting with the ester linkage of a phosphatidylcholine lipid, where it is stabilized by the electron withdrawing glycerol functional group. These results are in agreement with tryptophan's known role as an anchor for transmembrane proteins, though the tendency for binding of a positively charged tryptophan is surprising. We discuss the implications of our results on the mechanisms of unassisted permeation and penetration of small molecules within and across lipid bilayer membranes based on molecular charge, shape, and molecular interactions within the bilayer structure.
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Affiliation(s)
- Cari M. Anderson
- Department
of Chemistry, Institute for Computational Engineering and Sciences, Institute for Cellular
and Molecular Biology, Texas Materials Institute, The University of Texas at Austin, 2506 Speedway STOP A5300, Austin, Texas 78712, United States
| | - Alfredo Cardenas
- Department
of Chemistry, Institute for Computational Engineering and Sciences, Institute for Cellular
and Molecular Biology, Texas Materials Institute, The University of Texas at Austin, 2506 Speedway STOP A5300, Austin, Texas 78712, United States
| | - Ron Elber
- Department
of Chemistry, Institute for Computational Engineering and Sciences, Institute for Cellular
and Molecular Biology, Texas Materials Institute, The University of Texas at Austin, 2506 Speedway STOP A5300, Austin, Texas 78712, United States
| | - Lauren J. Webb
- Department
of Chemistry, Institute for Computational Engineering and Sciences, Institute for Cellular
and Molecular Biology, Texas Materials Institute, The University of Texas at Austin, 2506 Speedway STOP A5300, Austin, Texas 78712, United States
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23
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Carnevale KJF, Muroski ME, Vakil PN, Foley ME, Laufersky G, Kenworthy R, Zorio DAR, Morgan TJ, Levenson CW, Strouse GF. Selective Uptake Into Drug Resistant Mammalian Cancer by Cell Penetrating Peptide-Mediated Delivery. Bioconjug Chem 2018; 29:3273-3284. [DOI: 10.1021/acs.bioconjchem.8b00429] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Kate J. F. Carnevale
- Dept. of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32304, United States
| | - Megan E. Muroski
- Dept. of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32304, United States
| | - Parth N. Vakil
- Dept. of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32304, United States
| | - Megan E. Foley
- Dept. of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32304, United States
| | - Geoffry Laufersky
- Dept. of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32304, United States
| | - Rachael Kenworthy
- Dept. of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32304, United States
| | - Diego A. R. Zorio
- College of Medicine, Florida State University, Tallahassee, Florida 32304, United States
| | - Thomas J. Morgan
- College of Medicine, Florida State University, Tallahassee, Florida 32304, United States
| | - Cathy W. Levenson
- College of Medicine, Florida State University, Tallahassee, Florida 32304, United States
| | - Geoffrey F. Strouse
- Dept. of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32304, United States
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24
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Cao Z, Bian Y, Hu G, Zhao L, Kong Z, Yang Y, Wang J, Zhou Y. Bias-Exchange Metadynamics Simulation of Membrane Permeation of 20 Amino Acids. Int J Mol Sci 2018; 19:E885. [PMID: 29547563 PMCID: PMC5877746 DOI: 10.3390/ijms19030885] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/11/2018] [Accepted: 03/12/2018] [Indexed: 11/16/2022] Open
Abstract
Thermodynamics of the permeation of amino acids from water to lipid bilayers is an important first step for understanding the mechanism of cell-permeating peptides and the thermodynamics of membrane protein structure and stability. In this work, we employed bias-exchange metadynamics simulations to simulate the membrane permeation of all 20 amino acids from water to the center of a dipalmitoylphosphatidylcholine (DPPC) membrane (consists of 256 lipids) by using both directional and torsion angles for conformational sampling. The overall accuracy for the free energy profiles obtained is supported by significant correlation coefficients (correlation coefficient at 0.5-0.6) between our results and previous experimental or computational studies. The free energy profiles indicated that (1) polar amino acids have larger free energy barriers than nonpolar amino acids; (2) negatively charged amino acids are the most difficult to enter into the membrane; and (3) conformational transitions for many amino acids during membrane crossing is the key for reduced free energy barriers. These results represent the first set of simulated free energy profiles of membrane crossing for all 20 amino acids.
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Affiliation(s)
- Zanxia Cao
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China.
- College of Physics and Electronic Information, Dezhou University, Dezhou 253023, China.
| | - Yunqiang Bian
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China.
| | - Guodong Hu
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China.
- College of Physics and Electronic Information, Dezhou University, Dezhou 253023, China.
| | - Liling Zhao
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China.
- College of Physics and Electronic Information, Dezhou University, Dezhou 253023, China.
| | - Zhenzhen Kong
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China.
- College of Life Science, Shandong Normal University, Jinan 250014, China.
| | - Yuedong Yang
- Institute for Glycomics and School of Information and Communication Technology, Griffith University, Parklands Dr, Southport, QLD 4222, Australia.
- School of Data and Computer Science, Sun Yat-sen University, Guangzhou 510275, China.
| | - Jihua Wang
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China.
- College of Physics and Electronic Information, Dezhou University, Dezhou 253023, China.
| | - Yaoqi Zhou
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China.
- Institute for Glycomics and School of Information and Communication Technology, Griffith University, Parklands Dr, Southport, QLD 4222, Australia.
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25
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Shibutani S, Okazaki H, Iwata H. Dynamin-dependent amino acid endocytosis activates mechanistic target of rapamycin complex 1 (mTORC1). J Biol Chem 2017; 292:18052-18061. [PMID: 28808055 DOI: 10.1074/jbc.m117.776443] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 08/03/2017] [Indexed: 11/06/2022] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of protein synthesis and potential target for modifying cellular metabolism in various conditions, including cancer and aging. mTORC1 activity is tightly regulated by the availability of extracellular amino acids, and previous studies have revealed that amino acids in the extracellular fluid are transported to the lysosomal lumen. There, amino acids induce recruitment of cytoplasmic mTORC1 to the lysosome by the Rag GTPases, followed by mTORC1 activation by the small GTPase Ras homolog enriched in brain (Rheb). However, how the extracellular amino acids reach the lysosomal lumen and activate mTORC1 remains unclear. Here, we show that amino acid uptake by dynamin-dependent endocytosis plays a critical role in mTORC1 activation. We found that mTORC1 is inactivated when endocytosis is inhibited by overexpression of a dominant-negative form of dynamin 2 or by pharmacological inhibition of dynamin or clathrin. Consistently, the recruitment of mTORC1 to the lysosome was suppressed by the dynamin inhibition. The activity and lysosomal recruitment of mTORC1 were rescued by increasing intracellular amino acids via cycloheximide exposure or by Rag overexpression, indicating that amino acid deprivation is the main cause of mTORC1 inactivation via the dynamin inhibition. We further show that endocytosis inhibition does not induce autophagy even though mTORC1 inactivation is known to strongly induce autophagy. These findings open new perspectives for the use of endocytosis inhibitors as potential agents that can effectively inhibit nutrient utilization and shut down the upstream signals that activate mTORC1.
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Affiliation(s)
- Shusaku Shibutani
- From the Laboratory of Veterinary Hygiene, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Hana Okazaki
- From the Laboratory of Veterinary Hygiene, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Hiroyuki Iwata
- From the Laboratory of Veterinary Hygiene, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
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26
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Characterization of zinc amino acid complexes for zinc delivery in vitro using Caco-2 cells and enterocytes from hiPSC. Biometals 2017; 30:643-661. [PMID: 28717982 PMCID: PMC5646115 DOI: 10.1007/s10534-017-0033-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 07/06/2017] [Indexed: 02/07/2023]
Abstract
Zn is essential for growth and development. The bioavailability of Zn is affected by several factors such as other food components. It is therefore of interest, to understand uptake mechanisms of Zn delivering compounds to identify ways to bypass the inhibitory effects of these factors. Here, we studied the effect of Zn amino acid conjugates (ZnAAs) on the bioavailabilty of Zn. We used Caco-2 cells and enterocytes differentiated from human induced pluripotent stem cells from a control and Acrodermatitis enteropathica (AE) patient, and performed fluorescence based assays, protein biochemistry and atomic absorption spectrometry to characterize cellular uptake and absorption of ZnAAs. The results show that ZnAAs are taken up by AA transporters, leading to an intracellular enrichment of Zn mostly uninhibited by Zn uptake antagonists. Enterocytes from AE patients were unable to gain significant Zn through exposure to ZnCl2 but did not show differences with respect to ZnAAs. We conclude that ZnAAs may possess an advantage over classical Zn supplements such as Zn salts, as they may be able to increase bioavailability of Zn, and may be more efficient in patients with AE.
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27
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Bailey TL, Wang M, Solocinski J, Nathan BP, Chakraborty N, Menze MA. Protective effects of osmolytes in cryopreserving adherent neuroblastoma (Neuro-2a) cells. Cryobiology 2015; 71:472-80. [PMID: 26408850 DOI: 10.1016/j.cryobiol.2015.08.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 08/12/2015] [Accepted: 08/26/2015] [Indexed: 12/13/2022]
Abstract
A simple method to cryopreserve adherent monolayers of neuronal cells is currently not available, but the development of this technique could facilitate numerous applications in the field of biomedical engineering, cell line development, and drug screening. However, complex tissues of some exceptional animals survive freezing in nature. These animals are known to accumulate several small molecular weight solutes prior to freezing. Following a similar strategy, we investigated the effects of osmolytes such as trehalose, proline, and sucrose as additives to the traditional cryoprotectant dimethyl sulfoxide (Me2SO) in modulating the cryopreservation outcome of mouse neuroblastoma (Neuro-2a) cells. Neuro-2a cells adhered to cell culture plates were incubated for 24 h at varying concentrations of trehalose, proline, sucrose and combinations of these compounds. Cells were cryopreserved for 24 h and cell viability post-freezing and thawing was quantified by trypan blue exclusion assay. On average, only 13.5% of adherent cells survived freezing in the presence of 10% Me2SO alone (control). Pre-incubation of cells with medium containing both trehalose and proline severely decreased cell proliferation, but increased cell recovery to about 53% of control. Furthermore, characterization using Raman microspectroscopy revealed that the addition of both trehalose and proline to 10% Me2SO substantially increased the size, and altered the nature, of ice crystals formed during freezing. Our results suggest that pre-incubation of Neuro-2a cells with trehalose and proline in combination provides cell protection along with alterations of ice structure in order to increase cell survival post-freezing.
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Affiliation(s)
- Trisha L Bailey
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL 61920, USA
| | - Mian Wang
- Department of Mechanical Engineering, University of Michigan, Dearborn, MI 48128, USA
| | - Jason Solocinski
- Department of Mechanical Engineering, University of Michigan, Dearborn, MI 48128, USA
| | - Britto P Nathan
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL 61920, USA
| | - Nilay Chakraborty
- Department of Mechanical Engineering, University of Michigan, Dearborn, MI 48128, USA
| | - Michael A Menze
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL 61920, USA.
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28
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Cardenas AE, Shrestha R, Webb LJ, Elber R. Membrane permeation of a peptide: it is better to be positive. J Phys Chem B 2015; 119:6412-20. [PMID: 25941740 DOI: 10.1021/acs.jpcb.5b02122] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A joint experimental and computational study investigates the translocation of a tryptophan molecule through a phospholipid membrane. Time dependent spectroscopy of the tryptophan side chain determines the rate of permeation into 150 nm phospholipid vesicles. Atomically detailed simulations are conducted to calculate the free energy profiles and the permeation coefficient. Different charging conditions of the peptide (positive, negative, or zwitterion) are considered. Both experiment and simulation reproduce the qualitative trend and suggest that the fastest permeation is when the tryptophan is positively charged. The permeation mechanism, which is revealed by molecular dynamics simulations, is of a translocation assisted by a local defect. The influence of long-range electrostatic interactions, such as the membrane dipole potential on the permeation process, is not significant.
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Affiliation(s)
- Alfredo E Cardenas
- †Institute for Computational Engineering and Sciences and ‡Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Rebika Shrestha
- †Institute for Computational Engineering and Sciences and ‡Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Lauren J Webb
- †Institute for Computational Engineering and Sciences and ‡Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Ron Elber
- †Institute for Computational Engineering and Sciences and ‡Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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29
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Pernil R, Picossi S, Herrero A, Flores E, Mariscal V. Amino Acid Transporters and Release of Hydrophobic Amino Acids in the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120. Life (Basel) 2015; 5:1282-300. [PMID: 25915115 PMCID: PMC4500139 DOI: 10.3390/life5021282] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 04/16/2015] [Accepted: 04/20/2015] [Indexed: 01/15/2023] Open
Abstract
Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that can use inorganic compounds such as nitrate or ammonium as nitrogen sources. In the absence of combined nitrogen, it can fix N2 in differentiated cells called heterocysts. Anabaena also shows substantial activities of amino acid uptake, and three ABC-type transporters for amino acids have been previously characterized. Seven new loci encoding predicted amino acid transporters were identified in the Anabaena genomic sequence and inactivated. Two of them were involved in amino acid uptake. Locus alr2535-alr2541 encodes the elements of a hydrophobic amino acid ABC-type transporter that is mainly involved in the uptake of glycine. ORF all0342 encodes a putative transporter from the dicarboxylate/amino acid:cation symporter (DAACS) family whose inactivation resulted in an increased uptake of a broad range of amino acids. An assay to study amino acid release from Anabaena filaments to the external medium was set up. Net release of the alanine analogue α-aminoisobutyric acid (AIB) was observed when transport system N-I (a hydrophobic amino acid ABC-type transporter) was engaged in the uptake of a specific substrate. The rate of AIB release was directly proportional to the intracellular AIB concentration, suggesting leakage from the cells by diffusion.
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Affiliation(s)
- Rafael Pernil
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, E-41092 Seville, Spain.
| | - Silvia Picossi
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, E-41092 Seville, Spain.
| | - Antonia Herrero
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, E-41092 Seville, Spain.
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, E-41092 Seville, Spain.
| | - Vicente Mariscal
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, E-41092 Seville, Spain.
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30
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Wu X, Busschaert N, Wells NJ, Jiang YB, Gale PA. Dynamic Covalent Transport of Amino Acids across Lipid Bilayers. J Am Chem Soc 2015; 137:1476-84. [DOI: 10.1021/ja510063n] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Xin Wu
- Chemistry, University of Southampton, Southampton, SO17 1BJ, U.K
| | | | - Neil J. Wells
- Chemistry, University of Southampton, Southampton, SO17 1BJ, U.K
| | - Yun-Bao Jiang
- Department
of Chemistry, College of Chemistry and Chemical Engineering, and the
MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Xiamen University, Xiamen 361005, China
| | - Philip A. Gale
- Chemistry, University of Southampton, Southampton, SO17 1BJ, U.K
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31
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Richardson J, Shah B, Bondarenko PV, Bhebe P, Zhang Z, Nicklaus M, Kombe MC. Metabolomics analysis of soy hydrolysates for the identification of productivity markers of mammalian cells for manufacturing therapeutic proteins. Biotechnol Prog 2015; 31:522-31. [DOI: 10.1002/btpr.2050] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 12/17/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Jason Richardson
- Process Development; Amgen, Inc; One Amgen Center Drive Thousand Oaks CA 91320
| | - Bhavana Shah
- Process Development; Amgen, Inc; One Amgen Center Drive Thousand Oaks CA 91320
| | - Pavel V. Bondarenko
- Process Development; Amgen, Inc; One Amgen Center Drive Thousand Oaks CA 91320
| | - Prince Bhebe
- Process Development; Amgen, Inc; One Amgen Center Drive Thousand Oaks CA 91320
| | - Zhongqi Zhang
- Process Development; Amgen, Inc; One Amgen Center Drive Thousand Oaks CA 91320
| | - Michele Nicklaus
- Process Development; Amgen Inc; 4000 Nelson Road Longmont CO 80503
| | - Maua C. Kombe
- Process Development; Amgen Inc; 4000 Nelson Road Longmont CO 80503
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32
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Abstract
Metabolic crossfeeding is an important process that can broadly shape microbial communities. However, little is known about specific crossfeeding principles that drive the formation and maintenance of individuals within a mixed population. Here, we devised a series of synthetic syntrophic communities to probe the complex interactions underlying metabolic exchange of amino acids. We experimentally analyzed multimember, multidimensional communities of Escherichia coli of increasing sophistication to assess the outcomes of synergistic crossfeeding. We find that biosynthetically costly amino acids including methionine, lysine, isoleucine, arginine, and aromatics, tend to promote stronger cooperative interactions than amino acids that are cheaper to produce. Furthermore, cells that share common intermediates along branching pathways yielded more synergistic growth, but exhibited many instances of both positive and negative epistasis when these interactions scaled to higher dimensions. In more complex communities, we find certain members exhibiting keystone species-like behavior that drastically impact the community dynamics. Based on comparative genomic analysis of >6,000 sequenced bacteria from diverse environments, we present evidence suggesting that amino acid biosynthesis has been broadly optimized to reduce individual metabolic burden in favor of enhanced crossfeeding to support synergistic growth across the biosphere. These results improve our basic understanding of microbial syntrophy while also highlighting the utility and limitations of current modeling approaches to describe the dynamic complexities underlying microbial ecosystems. This work sets the foundation for future endeavors to resolve key questions in microbial ecology and evolution, and presents a platform to develop better and more robust engineered synthetic communities for industrial biotechnology.
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33
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Bonhenry D, Tarek M, Dehez F. Effects of Phospholipid Composition on the Transfer of a Small Cationic Peptide Across a Model Biological Membrane. J Chem Theory Comput 2013; 9:5675-84. [PMID: 26592298 DOI: 10.1021/ct400576e] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The transfer of a lysine amino acid analogue across phospholipid membrane models was investigated using molecular-dynamics simulations. The evolution of the protonation state of this small peptide as a function of its position inside the membrane was studied by determining the local pKa by means of free-energy calculations. Permeability and mean-first-passage time were evaluated and showed that the transfer occurs on the submillisecond time scale. Comparative studies were conducted to evaluate changes in the pKa arising from differences in the phospholipid chemical structure. We compared, hence, the effect of an ether vs an ester linkage of the lipid headgroup as well as linear vs branched lipid tails. The study reveals that protonated lysine residues can be buried further inside an ether lipid membrane than an ester lipid membrane, while branched lipids are found to stabilize less the charged form compared to their unbranched lipid chain counterparts.
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Affiliation(s)
- Daniel Bonhenry
- Université de Lorraine, SRSMC, UMR 7565 , Vandoeuvre-lès-Nancy, F-54500, France.,CNRS, SRSMC, UMR 7565 , Vandoeuvre-lès-Nancy, F-54500, France
| | - Mounir Tarek
- Université de Lorraine, SRSMC, UMR 7565 , Vandoeuvre-lès-Nancy, F-54500, France.,CNRS, SRSMC, UMR 7565 , Vandoeuvre-lès-Nancy, F-54500, France
| | - François Dehez
- Université de Lorraine, SRSMC, UMR 7565 , Vandoeuvre-lès-Nancy, F-54500, France.,CNRS, SRSMC, UMR 7565 , Vandoeuvre-lès-Nancy, F-54500, France
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34
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Martins-Costa MTC, Ruiz-Lopez MF. Amino Acid Capture by Aqueous Interfaces. Implications for Biological Uptake. J Phys Chem B 2013; 117:12469-74. [DOI: 10.1021/jp4083689] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marilia T. C. Martins-Costa
- SRSMC,
UMR 7565, University of Lorraine, BP 70239, 54506, Vandoeuvre-les-Nancy, France
- SRSMC, UMR 7565, CNRS, BP 70239, 54506, Vandoeuvre-les-Nancy, France
| | - Manuel F. Ruiz-Lopez
- SRSMC,
UMR 7565, University of Lorraine, BP 70239, 54506, Vandoeuvre-les-Nancy, France
- SRSMC, UMR 7565, CNRS, BP 70239, 54506, Vandoeuvre-les-Nancy, France
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35
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Ferraro V, Ferreira Jorge R, Cruz IB, Antunes F, Sarmento B, Castro PML, Pintado ME. In vitrointestinal absorption of amino acid mixtures extracted from codfish (Gadus morhuaL.) salting wastewater. Int J Food Sci Technol 2013. [DOI: 10.1111/ijfs.12269] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Vincenza Ferraro
- CBQF - Centro de Biotecnologia e Química Fina; Escola Superior de Biotecnologia; Universidade Católica Portuguesa; Rua Dr. António Bernardino de Almeida Porto 4200-072 Portugal
- WeDoTech - Companhia de Ideias e Tecnologias, Lda./CiDEB; Escola Superior de Biotecnologia; Universidade Católica Portuguesa; Rua Dr. António Bernardino de Almeida Porto 4200-072 Portugal
| | - Ruben Ferreira Jorge
- WeDoTech - Companhia de Ideias e Tecnologias, Lda./CiDEB; Escola Superior de Biotecnologia; Universidade Católica Portuguesa; Rua Dr. António Bernardino de Almeida Porto 4200-072 Portugal
| | - Isabel B. Cruz
- CBQF - Centro de Biotecnologia e Química Fina; Escola Superior de Biotecnologia; Universidade Católica Portuguesa; Rua Dr. António Bernardino de Almeida Porto 4200-072 Portugal
- WeDoTech - Companhia de Ideias e Tecnologias, Lda./CiDEB; Escola Superior de Biotecnologia; Universidade Católica Portuguesa; Rua Dr. António Bernardino de Almeida Porto 4200-072 Portugal
| | - Filipa Antunes
- INEB-Instituto de Engenharia Biomédica; NEWTherapiesGroup; Universidade do Porto; Rua do Campo Alegre 823 Porto 4050-048 Portugal
| | - Bruno Sarmento
- INEB-Instituto de Engenharia Biomédica; NEWTherapiesGroup; Universidade do Porto; Rua do Campo Alegre 823 Porto 4050-048 Portugal
- CICS; HealthSciences Research Center; Instituto Superior de Ciências da Saúde Norte; Rua Central de Gandra 1317 4585-116 Gandra Portugal
| | - Paula M. L. Castro
- CBQF - Centro de Biotecnologia e Química Fina; Escola Superior de Biotecnologia; Universidade Católica Portuguesa; Rua Dr. António Bernardino de Almeida Porto 4200-072 Portugal
| | - Manuela E. Pintado
- CBQF - Centro de Biotecnologia e Química Fina; Escola Superior de Biotecnologia; Universidade Católica Portuguesa; Rua Dr. António Bernardino de Almeida Porto 4200-072 Portugal
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36
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Chen L, Si W, Zhang L, Tang G, Li ZT, Hou JL. Chiral Selective Transmembrane Transport of Amino Acids through Artificial Channels. J Am Chem Soc 2013; 135:2152-5. [DOI: 10.1021/ja312704e] [Citation(s) in RCA: 235] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Lei Chen
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433,
China
| | - Wen Si
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433,
China
| | - Liang Zhang
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433,
China
| | - Gangfeng Tang
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433,
China
| | - Zhan-Ting Li
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433,
China
| | - Jun-Li Hou
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433,
China
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37
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Yasuhara K, Kawataki T, Okuda S, Oshima S, Kikuchi JI. Spontaneously formed semipermeable organic–inorganic hybrid vesicles permitting molecular weight selective transmembrane passage. Chem Commun (Camb) 2013; 49:665-7. [DOI: 10.1039/c2cc36662b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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38
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Transport and interaction of cosmetic product material within the ocular surface: Beauty and the beastly symptoms of toxic tears. Cont Lens Anterior Eye 2012; 35:247-59. [PMID: 22890123 DOI: 10.1016/j.clae.2012.07.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 07/23/2012] [Accepted: 07/24/2012] [Indexed: 11/24/2022]
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39
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Cardenas AE, Jas GS, DeLeon KY, Hegefeld WA, Kuczera K, Elber R. Unassisted transport of N-acetyl-L-tryptophanamide through membrane: experiment and simulation of kinetics. J Phys Chem B 2012; 116:2739-50. [PMID: 22313494 PMCID: PMC3302722 DOI: 10.1021/jp2102447] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cellular transport machinery, such as channels and pumps, is working against the background of unassisted material transport through membranes. The permeation of a blocked tryptophan through a 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) membrane is investigated to probe unassisted or physical transport. The transport rate is measured experimentally and modeled computationally. The time scale measured by parallel artificial membrane permeation assay (PAMPA) experiments is ~8 h. Simulations with the milestoning algorithm suggest mean first passage time (MFPT) of ~4 h and the presence of a large barrier at the center of the bilayer. A similar calculation with the solubility-diffusion model yields a MFPT of ~15 min. This permeation rate is 9 orders of magnitude slower than the permeation rate of only a tryptophan side chain (computed by us and others). This difference suggests critical dependence of transport time on permeant size and hydrophilicity. Analysis of the simulation results suggests that the permeant partially preserves hydrogen bonding of the peptide backbone to water and lipid molecules even when it is moving closer to the bilayer center. As a consequence, defects of the membrane structure are developed to assist permeation.
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Affiliation(s)
- Alfredo E Cardenas
- Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas 78712, USA.
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40
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A ligand-based approach for enhancing the pharmacokinetic profile of highly charged antibacterial agents. Med Chem Res 2012. [DOI: 10.1007/s00044-010-9538-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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41
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Martins PT, Velazquez-Campoy A, Vaz WLC, Cardoso RMS, Valério J, Moreno MJ. Kinetics and Thermodynamics of Chlorpromazine Interaction with Lipid Bilayers: Effect of Charge and Cholesterol. J Am Chem Soc 2012; 134:4184-95. [DOI: 10.1021/ja209917q] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Patrícia T. Martins
- Chemistry Department FCTUC, Largo D. Dinis, Rua Larga, 3004-535 Coimbra,
Portugal
| | - Adrian Velazquez-Campoy
- Institute of Biocomputation
and Physics of Complex Systems (BIFI), Universidad de Zaragoza, 50018 Zaragoza, Spain, Unidad Asociada BIFI-IQFR,
CSIC, Zaragoza, Spain
- Fundación ARAID, Diputación General de Aragón, Spain
| | - Winchil L. C. Vaz
- Chemistry Department FCTUC, Largo D. Dinis, Rua Larga, 3004-535 Coimbra,
Portugal
| | - Renato M. S. Cardoso
- Chemistry Department FCTUC, Largo D. Dinis, Rua Larga, 3004-535 Coimbra,
Portugal
| | - Joana Valério
- Instituto de Tecnologia Química e Biológica − UNL, Av.
da República-EAN, 2780-157 Oeiras, Portugal
| | - Maria João Moreno
- Chemistry Department FCTUC, Largo D. Dinis, Rua Larga, 3004-535 Coimbra,
Portugal
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42
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Martins-Costa MTC, Ruiz-López MF. Simulation of amino acid diffusion across water/hydrophobic interfaces. Phys Chem Chem Phys 2011; 13:11579-82. [DOI: 10.1039/c1cp20117d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Meleshkevitch EA, Robinson M, Popova LB, Miller MM, Harvey WR, Boudko DY. Cloning and functional expression of the first eukaryotic Na+-tryptophan symporter, AgNAT6. ACTA ACUST UNITED AC 2009; 212:1559-67. [PMID: 19411550 DOI: 10.1242/jeb.027383] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The nutrient amino acid transporter (NAT) subfamily of the neurotransmitter sodium symporter family (NSS, also known as the solute carrier family 6, SLC6) represents transport mechanisms with putative synergistic roles in the absorption of essential and conditionally essential neutral amino acids. It includes a large paralogous expansion of insect-specific genes, with seven genes from the genome of the malaria mosquito, Anopheles gambiae. One of the An. gambiae NATs, AgNAT8, was cloned, functionally expressed and characterized in X. laevis oocytes as a cation-coupled symporter of aromatic amino acids, preferably l-phenylalanine, l-tyrosine and l-DOPA. To explore an evolutionary trend of NAT-SLC6 phenotypes, we have cloned and characterized AgNAT6, which represents a counterpart of AgNAT8 descending from a recent gene duplication (53.1% pairwise sequence identity). In contrast to AgNAT8, which preferably mediates the absorption of phenol-branched substrates, AgNAT6 mediates the absorption of indole-branched substrates with highest apparent affinity to tryptophan (K(0.5)(Trp)=1.3 micromol l(-1) vs K(0.5)(Phe)=430 micromol l(-1)) and [2 or 1 Na(+) or K(+)]:[aromatic substrate] stoichiometry. AgNAT6 is highly transcribed in absorptive and secretory regions of the alimentary canal and specific neuronal structures, including the neuropile of ventral ganglia and sensory afferents. The alignment of AgNATs and LeuT(Aa), a bacterial NAT with a resolved 3D structure, reveals three amino acid differences in the substrate-binding pocket that may be responsible for the indole- vs phenol-branch selectivity of AgNAT6 vs AgNAT8. The identification of transporters with a narrow selectivity for essential amino acids suggests that basal expansions in the SLC6 family involved duplication and retention of NATs, improving the absorption and distribution of under-represented essential amino acids and related metabolites. The identified physiological and expression profiles suggest unique roles of AgNAT6 in the active absorption of indole-branched substrates that are used in the synthesis of the neurotransmitter serotonin as well as the key circadian hormone and potent free-radical scavenger melatonin.
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Affiliation(s)
- Ella A Meleshkevitch
- Department of Physiology and Biophysics, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, USA
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Abstract
Languishing for many years in the shadow of plant inorganic nitrogen (N) nutrition research, studies of organic N uptake have attracted increased attention during the last decade. The capacity of plants to acquire organic N, demonstrated in laboratory and field settings, has thereby been well established. Even so, the ecological significance of organic N uptake for plant N nutrition is still a matter of discussion. Several lines of evidence suggest that plants growing in various ecosystems may access organic N species. Many soils display amino acid concentrations similar to, or higher than, those of inorganic N, mainly as a result of rapid hydrolysis of soil proteins. Transporters mediating amino acid uptake have been identified both in mycorrhizal fungi and in plant roots. Studies of endogenous metabolism of absorbed amino acids suggest that L- but not D-enantiomers are efficiently utilized. Dual labelled amino acids supplied to soil have provided strong evidence for plant uptake of organic N in the field but have failed to provide information on the quantitative importance of this process. Thus, direct evidence that organic N contributes significantly to plant N nutrition is still lacking. Recent progress in our understanding of the mechanisms underlying plant organic N uptake may open new avenues for the exploration of this subject.
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Affiliation(s)
- Torgny Näsholm
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Knut Kielland
- Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska 99775-0180, USA
| | - Ulrika Ganeteg
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
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Chen Y, Arriaga EA. Individual electrophoretic mobilities of liposomes and acidic organelles displaying pH gradients across their membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:5584-90. [PMID: 17402758 DOI: 10.1021/la0633233] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
This report focuses on measuring the individual electrophoretic mobilities of liposomes with different pH gradients across their membrane using capillary electrophoresis with laser-induced fluorescence detection (CE-LIF). The results from the individual analysis of liposomes show that, using surface electrostatic theories and the electrokinetic theory as the first approximation, zeta potential contributes more significantly to the electrophoretic mobility of liposomes than liposomal size. For liposomes with an outer pH 7.4 (pH(o) 7.4) and a net negative outer surface charge, the most negative electrophoretic mobilities occur when the inner pH (pH(i)) is 6.8; at higher or lower pH(i), the electrophoretic mobilities are less negative. The theories mentioned above cannot explain these pH-induced electrophoretic mobility shifts. The capacity theory, predicting an induced electrical charge on the surface of liposomes, can only explain the results at pH(i) > 6.8. In this report, we hypothesize that there is a flip-flop process of phospholipids, which refers to the exchange of phospholipids between the outer and inner layers of the membrane. This flip-flop is caused by the pH gradient and membrane instability and results in the observed electrophoretic mobility changes when pH(i) is <6.8. Furthermore, it is found that the mobilities of acidic organelles are consistent with the predictions of liposome models we used here.
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Affiliation(s)
- Yun Chen
- Department of Chemistry, University of Minnesota, 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, USA
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Gardiner J, Thomae AV, Mathad RI, Seebach D, Krämer SD. Comparison of permeation through phosphatidylcholine bilayers of N-dipicolinyl-alpha- and -beta-oligopeptides. Chem Biodivers 2007; 3:1181-201. [PMID: 17193232 DOI: 10.1002/cbdv.200690120] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cell-membrane permeation of small therapeutic peptides and peptidomimetics is a fundamental issue in pharmaceutical research. Using a Tb(3+)-based permeation assay, we have examined the ability of alpha- and beta-peptides, bearing proteinogenic side chains and an N-terminal dipicolinic acid (DPA) monoamide group, to enter liposomes composed of egg phosphatidylcholine bilayers. A series of 12 DPA-peptides of increasing chain length was prepared and characterized by CD and NMR analysis. An interesting destabilizing effect of the N-terminal DPA group on the helical structure of a beta-hexapeptide was discovered. Significant differences in permeation were observed between the DPA-alpha- and the DPA-beta-peptides, with all beta-peptidic compounds permeating better than their alpha-analogs. Thus, beta-peptides have been shown to interact with lipid bilayers in a manner that is distinctly different from that of alpha-peptides. Together with the fact that beta-peptides are proteolytically stable in mammalian organisms, and that they fold to form helices and hairpin turns with short chain lengths, the new results further emphasize the biomedical potential of beta-peptides.
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Affiliation(s)
- James Gardiner
- Laboratorium für Organische Chemie, Departement Chemie und Angewandte Biowissenschaften, ETH-Zürich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich
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Cavazza A, Marini M, Spagnoli GC, Adamina M, Roda LG. Permeability of Phospholipid Vesicles to the Tumor Antigen Epitope gp100280–288. ChemMedChem 2006; 1:816-20. [PMID: 16902935 DOI: 10.1002/cmdc.200600019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Antonella Cavazza
- Dipartimento di Neuroscienze, Università degli Studi di Roma Tor Vergata, Via Montpellier 1, 00133 Roma, Italy
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Janas T, Janas T, Yarus M. A membrane transporter for tryptophan composed of RNA. RNA (NEW YORK, N.Y.) 2004; 10:1541-9. [PMID: 15383677 PMCID: PMC1370641 DOI: 10.1261/rna.7112704] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2004] [Accepted: 07/09/2004] [Indexed: 05/24/2023]
Abstract
We have incorporated an RNA binding site for the biological amino acid tryptophan within an RNA complex with affinity for phospholipid bilayer membranes. The resulting RNA (9:10Trp) creates a selective route through the bilayer for the amino acid. Binding and enhanced tryptophan permeability are nonlinear in RNA concentration, suggesting that RNA aggregation is required for both. Tryptophan permeability saturates with increased concentration, though at approximately 1000-fold greater level than when binding a free aptamer. The RNA (9:10Trp) complex, bound at a mean of two per liposome, halves the activation energy for tryptophan transport (to 46 kJ/mole), specifically increasing tryptophan entry to a maximal velocity of 0.5 sec(-1) per liposome with little or no accompanying increase in general permeability. Individual RNAs turn over tens of thousands of times at high tryptophan concentration. Thus, a specific passive membrane transporter whose properties overlap those of single-molecule transporter proteins, can be made of RNA alone. Permeability changes probably rely on disturbances in lipid conformation as well as on an advantageous low free energy position for tryptophan at the membrane. Other RNA activities may yield other RNA-membrane nanosystems via this route.
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Affiliation(s)
- Teresa Janas
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347, USA
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WECZOREK P, TOMASZEWSKA M. TRANSPORT OF AMINO ACIDS THROUGH LIQUID MEMBRANES SUPPORTED ON NOVEL POLY(VINYLIDENEFLUORIDE) POROUS FLAT-SHEET MATRIX. SOLVENT EXTRACTION AND ION EXCHANGE 1997. [DOI: 10.1080/07366299708934511] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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In vitro models for selection of development candidates. Permeability studies to define mechanisms of absorption enhancement. Adv Drug Deliv Rev 1997. [DOI: 10.1016/s0169-409x(96)00434-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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