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Farsi Z, Jahn R, Woehler A. Proton electrochemical gradient: Driving and regulating neurotransmitter uptake. Bioessays 2017; 39. [PMID: 28383767 DOI: 10.1002/bies.201600240] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Accumulation of neurotransmitters in the lumen of synaptic vesicles (SVs) relies on the activity of the vacuolar-type H+ -ATPase. This pump drives protons into the lumen, generating a proton electrochemical gradient (ΔμH+ ) across the membrane. Recent work has demonstrated that the balance between the chemical (ΔpH) and electrical (ΔΨ) components of ΔμH+ is regulated differently by some distinct vesicle types. As different neurotransmitter transporters use ΔpH and ΔΨ with different relative efficiencies, regulation of this gradient balance has the potential to influence neurotransmitter uptake. Nevertheless, the underlying mechanisms responsible for this regulation remain poorly understood. In this review, we provide an overview of current neurotransmitter uptake models, with a particular emphasis on the distinct roles of the electrical and chemical gradients and current hypotheses for regulatory mechanisms.
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Affiliation(s)
- Zohreh Farsi
- Max-Delbrück Center for Molecular Medicine, Berlin Institute for Medical Systems Biology, Berlin, Germany
| | - Reinhard Jahn
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Andrew Woehler
- Max-Delbrück Center for Molecular Medicine, Berlin Institute for Medical Systems Biology, Berlin, Germany
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52
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Poroca DR, Pelis RM, Chappe VM. ClC Channels and Transporters: Structure, Physiological Functions, and Implications in Human Chloride Channelopathies. Front Pharmacol 2017; 8:151. [PMID: 28386229 PMCID: PMC5362633 DOI: 10.3389/fphar.2017.00151] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/09/2017] [Indexed: 02/04/2023] Open
Abstract
The discovery of ClC proteins at the beginning of the 1990s was important for the development of the Cl- transport research field. ClCs form a large family of proteins that mediate voltage-dependent transport of Cl- ions across cell membranes. They are expressed in both plasma and intracellular membranes of cells from almost all living organisms. ClC proteins form transmembrane dimers, in which each monomer displays independent ion conductance. Eukaryotic members also possess a large cytoplasmic domain containing two CBS domains, which are involved in transport modulation. ClC proteins function as either Cl- channels or Cl-/H+ exchangers, although all ClC proteins share the same basic architecture. ClC channels have two gating mechanisms: a relatively well-studied fast gating mechanism, and a slow gating mechanism, which is poorly defined. ClCs are involved in a wide range of physiological processes, including regulation of resting membrane potential in skeletal muscle, facilitation of transepithelial Cl- reabsorption in kidneys, and control of pH and Cl- concentration in intracellular compartments through coupled Cl-/H+ exchange mechanisms. Several inherited diseases result from C1C gene mutations, including myotonia congenita, Bartter's syndrome (types 3 and 4), Dent's disease, osteopetrosis, retinal degeneration, and lysosomal storage diseases. This review summarizes general features, known or suspected, of ClC structure, gating and physiological functions. We also discuss biophysical properties of mammalian ClCs that are directly involved in the pathophysiology of several human inherited disorders, or that induce interesting phenotypes in animal models.
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Affiliation(s)
- Diogo R Poroca
- Department of Physiology and Biophysics, Dalhousie University, Halifax NS, Canada
| | - Ryan M Pelis
- Department of Pharmacology, Dalhousie University, Halifax NS, Canada
| | - Valérie M Chappe
- Department of Physiology and Biophysics, Dalhousie University, Halifax NS, Canada
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53
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Takagi S, Takahashi Y, Sugimura K, Nishikawa M, Takakura Y. Application of Magnesium Pyrophosphate-Based Sponge-Like Microparticles to Enhance the Delivery Efficiency and Adjuvant Effects of Polyriboinosinic-Polyribocytidylic Acid in Immune Cells. J Pharm Sci 2016; 105:766-772. [PMID: 26869429 DOI: 10.1016/j.xphs.2015.11.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 11/09/2015] [Accepted: 11/10/2015] [Indexed: 12/15/2022]
Abstract
The magnesium pyrophosphate particle (MgPP) is a unique and safe carrier that is prepared by simply mixing magnesium chloride and sodium pyrophosphate. In this study, we investigated whether MgPP can be used to deliver nucleic acid-based adjuvants to immune cells. Polyriboinosinic-polyribocytidylic acid (polyI:C), a ligand for toll-like receptor 3, was selected as a model nucleic acid-based adjuvant. PolyI:C-loaded MgPP (polyI:C-MgPP) was prepared by adding polyI:C during the MgPP preparation process. Efficient loading of polyI:C into MgPP was confirmed by measuring the absorbance at 260 nm after disruption of polyI:C-MgPP by ethylenediaminetetraacetic acid. Scanning electron microscopy revealed that both MgPP and polyI:C-MgPP had a unique sponge-like shape with a diameter of approximately 1 μm. PolyI:C-MgPP was more efficiently taken up by toll-like receptor 3-positive RAW264.7 cells than naked polyI:C, and its uptake stimulated increased tumor necrosis factor-α production. When the presentation of ovalbumin (OVA), a model antigen, was evaluated after the addition of OVA along with naked polyI:C or polyI:C-MgPP to mouse dendritic DC2.4 cells, polyI:C-MgPP substantially increased OVA presentation. These results indicate that MgPP is a useful delivery vehicle for polyI:C and that polyI:C-MgPP is an effective immune cell adjuvant.
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Affiliation(s)
- Shoichi Takagi
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuki Takahashi
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kanako Sugimura
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Makiya Nishikawa
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yoshinobu Takakura
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
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Marcoline FV, Ishida Y, Mindell JA, Nayak S, Grabe M. A mathematical model of osteoclast acidification during bone resorption. Bone 2016; 93:167-180. [PMID: 27650914 PMCID: PMC5077641 DOI: 10.1016/j.bone.2016.09.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 08/16/2016] [Accepted: 09/09/2016] [Indexed: 12/01/2022]
Abstract
Bone resorption by osteoclasts occurs through the creation of a sealed extracellular compartment (ECC), or pit, adjacent to the bone that is subsequently acidified through a complex biological process. The low pH of the pit dissolves the bone mineral and activates acid proteases that further break down the bone matrix. There are many ion channels, transporters, and soluble proteins involved in osteoclast mediated resorption, and in the past few years, there has been an increased understanding of the identity and properties of some key proteins such as the ClC-7 Cl-/H+ antiporter and the HV1 proton channel. Here we present a detailed mathematical model of osteoclast acidification that includes the influence of many of the key regulatory proteins. The primary enzyme responsible for acidification is the vacuolar H+-ATPase (V-ATPase), which pumps protons from the cytoplasm into the pit. Unlike the acidification of small lysosomes, the pit is so large that protons become depleted from the cytoplasm. Hence, proton buffering and production in the cytoplasm by carbonic anhydrase II (CAII) is potentially important for proper acidification. We employ an ordinary differential equations (ODE)-based model that accounts for the changes in ionic species in the cytoplasm and the resorptive pit. Additionally, our model tracks ionic flow between the cytoplasm and the extracellular solution surrounding the cell. Whenever possible, the properties of individual channels and transporters are calibrated based on electrophysiological measurements, and physical properties of the cell, such as buffering capacity, surface areas, and volumes, are estimated based on available data. Our model reproduces many of the experimental findings regarding the role of key proteins in the acidification process, and it allows us to estimate, among other things, number of active pumps, protons moved, and the influence of particular mutations implicated in disease.
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Affiliation(s)
- Frank V Marcoline
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Yoichi Ishida
- Department of Philosophy, Ohio University, Athens, OH 45701, USA
| | - Joseph A Mindell
- Membrane Transport Biophysics Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Smita Nayak
- Swedish Center for Research and Innovation, Swedish Health Services, Seattle, WA 98122, USA
| | - Michael Grabe
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA.
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55
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Unique pH dynamics in GABAergic synaptic vesicles illuminates the mechanism and kinetics of GABA loading. Proc Natl Acad Sci U S A 2016; 113:10702-7. [PMID: 27601664 DOI: 10.1073/pnas.1604527113] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
GABA acts as the major inhibitory neurotransmitter in the mammalian brain, shaping neuronal and circuit activity. For sustained synaptic transmission, synaptic vesicles (SVs) are required to be recycled and refilled with neurotransmitters using an H(+) electrochemical gradient. However, neither the mechanism underlying vesicular GABA uptake nor the kinetics of GABA loading in living neurons have been fully elucidated. To characterize the process of GABA uptake into SVs in functional synapses, we monitored luminal pH of GABAergic SVs separately from that of excitatory glutamatergic SVs in cultured hippocampal neurons. By using a pH sensor optimal for the SV lumen, we found that GABAergic SVs exhibited an unexpectedly higher resting pH (∼6.4) than glutamatergic SVs (pH ∼5.8). Moreover, unlike glutamatergic SVs, GABAergic SVs displayed unique pH dynamics after endocytosis that involved initial overacidification and subsequent alkalization that restored their resting pH. GABAergic SVs that lacked the vesicular GABA transporter (VGAT) did not show the pH overshoot and acidified further to ∼6.0. Comparison of luminal pH dynamics in the presence or absence of VGAT showed that VGAT operates as a GABA/H(+) exchanger, which is continuously required to offset GABA leakage. Furthermore, the kinetics of GABA transport was slower (τ > 20 s at physiological temperature) than that of glutamate uptake and may exceed the time required for reuse of exocytosed SVs, allowing reuse of incompletely filled vesicles in the presence of high demand for inhibitory transmission.
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56
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Veshaguri S, Christensen SM, Kemmer GC, Ghale G, Møller MP, Lohr C, Christensen AL, Justesen BH, Jørgensen IL, Schiller J, Hatzakis NS, Grabe M, Pomorski TG, Stamou D. Direct observation of proton pumping by a eukaryotic P-type ATPase. Science 2016; 351:1469-73. [PMID: 27013734 DOI: 10.1126/science.aad6429] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 02/23/2016] [Indexed: 12/12/2022]
Abstract
In eukaryotes, P-type adenosine triphosphatases (ATPases) generate the plasma membrane potential and drive secondary transport systems; however, despite their importance, their regulation remains poorly understood. We monitored at the single-molecule level the activity of the prototypic proton-pumping P-type ATPase Arabidopsis thaliana isoform 2 (AHA2). Our measurements, combined with a physical nonequilibrium model of vesicle acidification, revealed that pumping is stochastically interrupted by long-lived (~100 seconds) inactive or leaky states. Allosteric regulation by pH gradients modulated the switch between these states but not the pumping or leakage rates. The autoinhibitory regulatory domain of AHA2 reduced the intrinsic pumping rates but increased the dwell time in the active pumping state. We anticipate that similar functional dynamics underlie the operation and regulation of many other active transporters.
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Affiliation(s)
- Salome Veshaguri
- Bionanotecnology and Nanomedicine Laboratory, University of Copenhagen, Copenhagen, Denmark. Department of Chemistry, University of Copenhagen, Copenhagen, Denmark. Nano-Science Center, University of Copenhagen, Copenhagen, Denmark. Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
| | - Sune M Christensen
- Bionanotecnology and Nanomedicine Laboratory, University of Copenhagen, Copenhagen, Denmark. Department of Chemistry, University of Copenhagen, Copenhagen, Denmark. Nano-Science Center, University of Copenhagen, Copenhagen, Denmark. Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
| | - Gerdi C Kemmer
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg Denmark
| | - Garima Ghale
- Bionanotecnology and Nanomedicine Laboratory, University of Copenhagen, Copenhagen, Denmark. Department of Chemistry, University of Copenhagen, Copenhagen, Denmark. Nano-Science Center, University of Copenhagen, Copenhagen, Denmark. Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
| | - Mads P Møller
- Bionanotecnology and Nanomedicine Laboratory, University of Copenhagen, Copenhagen, Denmark. Department of Chemistry, University of Copenhagen, Copenhagen, Denmark. Nano-Science Center, University of Copenhagen, Copenhagen, Denmark. Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
| | - Christina Lohr
- Bionanotecnology and Nanomedicine Laboratory, University of Copenhagen, Copenhagen, Denmark. Department of Chemistry, University of Copenhagen, Copenhagen, Denmark. Nano-Science Center, University of Copenhagen, Copenhagen, Denmark. Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
| | - Andreas L Christensen
- Bionanotecnology and Nanomedicine Laboratory, University of Copenhagen, Copenhagen, Denmark. Department of Chemistry, University of Copenhagen, Copenhagen, Denmark. Nano-Science Center, University of Copenhagen, Copenhagen, Denmark. Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
| | - Bo H Justesen
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg Denmark
| | - Ida L Jørgensen
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg Denmark
| | - Jürgen Schiller
- Institute of Medical Physics and Biophysics, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Nikos S Hatzakis
- Bionanotecnology and Nanomedicine Laboratory, University of Copenhagen, Copenhagen, Denmark. Department of Chemistry, University of Copenhagen, Copenhagen, Denmark. Nano-Science Center, University of Copenhagen, Copenhagen, Denmark. Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
| | - Michael Grabe
- Cardiovascular Research Institute, Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143, USA
| | - Thomas Günther Pomorski
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg Denmark
| | - Dimitrios Stamou
- Bionanotecnology and Nanomedicine Laboratory, University of Copenhagen, Copenhagen, Denmark. Department of Chemistry, University of Copenhagen, Copenhagen, Denmark. Nano-Science Center, University of Copenhagen, Copenhagen, Denmark. Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
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57
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Farsi Z, Preobraschenski J, van den Bogaart G, Riedel D, Jahn R, Woehler A. Single-vesicle imaging reveals different transport mechanisms between glutamatergic and GABAergic vesicles. Science 2016; 351:981-4. [DOI: 10.1126/science.aad8142] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/14/2016] [Indexed: 12/13/2022]
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58
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Kuno M, Li G, Moriura Y, Hino Y, Kawawaki J, Sakai H. Acid-inducible proton influx currents in the plasma membrane of murine osteoclast-like cells. Pflugers Arch 2016; 468:837-47. [PMID: 26843093 DOI: 10.1007/s00424-016-1796-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/02/2016] [Accepted: 01/25/2016] [Indexed: 01/20/2023]
Abstract
Acidification of the resorption pits, which is essential for dissolving bone, is produced by secretion of protons through vacuolar H(+)-ATPases in the plasma membrane of bone-resorbing cells, osteoclasts. Consequently, osteoclasts face highly acidic extracellular environments, where the pH gradient across the plasma membrane could generate a force driving protons into the cells. Proton influx mechanisms during the acid exposure are largely unknown, however. In this study, we investigated extracellular-acid-inducible proton influx currents in osteoclast-like cells derived from a macrophage cell line (RAW264). Decreasing extracellular pH to <5.5 induced non-ohmic inward currents. The reversal potentials depended on the pH gradients across the membrane and were independent of concentrations of Na(+), Cl(-), and HCO3 (-), suggesting that they were carried largely by protons. The acid-inducible proton influx currents were not inhibited by amiloride, a widely used blocker for cation channels/transporters, or by 4,4'-diisothiocyanato-2,2'-stilbenesulfonate(DIDS) which blocks anion channels/transporters. Additionally, the currents were not significantly affected by V-ATPase inhibitors, bafilomycin A1 and N,N'-dicyclohexylcarbodiimide. Extracellular Ca(2+) (10 mM) did not affect the currents, but 1 mM ZnCl2 decreased the currents partially. The intracellular pH in the vicinity of the plasma membrane was dropped by the acid-inducible H(+) influx currents, which caused overshoot of the voltage-gated H(+) channels after removal of acids. The H(+) influx currents were smaller in undifferentiated, mononuclear RAW cells and were negligible in COS7 cells. These data suggest that the acid-inducible H(+) influx (H(+) leak) pathway may be an additional mechanism modifying the pH environments of osteoclasts upon exposure to strong acids.
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Affiliation(s)
- Miyuki Kuno
- Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan.
| | - Guangshuai Li
- Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan
| | - Yoshie Moriura
- Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan
| | - Yoshiko Hino
- Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan
| | - Junko Kawawaki
- Central Laboratory, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka, 545-8585, Japan
| | - Hiromu Sakai
- Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan
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59
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Hayes CN, Zhang Y, Makokha GN, Hasan MZ, Omokoko MD, Chayama K. Early events in hepatitis B virus infection: From the cell surface to the nucleus. J Gastroenterol Hepatol 2016; 31:302-9. [PMID: 26414381 DOI: 10.1111/jgh.13175] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/14/2015] [Indexed: 12/12/2022]
Abstract
While most adults are able to clear acute hepatitis B virus (HBV) infection, chronic HBV infection is recalcitrant to current therapy because of the persistence of covalently closed circular DNA in the nucleus. Complete clearance of the virus in these patients is rare, and long-term therapy with interferon and/or nucleoside analogues may be required in an attempt to suppress viral replication and prevent progressive liver damage. The difficulty of establishing HBV infection in cell culture and experimental organisms has hindered efforts to elucidate details of the HBV life cycle, but it has also revealed the importance of the cellular microenvironment required for HBV binding and entry. Recent studies have demonstrated an essential role of sodium-taurocholate cotransporting polypeptide as a functional receptor in HBV infection, which has facilitated the development of novel infection systems and opened the way for more detailed understanding of the early steps of HBV infection as well as a potential new therapeutic target. However, many gaps remain in understanding of how HBV recognizes and attaches to hepatocytes prior to binding to sodium-taurocholate cotransporting polypeptide, as well as events that are triggered after binding, including entry into the cell, intracellular transport, and passage through the nuclear pore complex. This review summarizes current knowledge of the initial stages of HBV infection leading to the establishment of covalently closed circular DNA in the nucleus.
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Affiliation(s)
- C Nelson Hayes
- Department of Gastroenterology and Metabolism, Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.,Laboratory for Digestive Diseases, Center for Genomic Medicine, RIKEN, Hiroshima, Japan.,Liver Research Project Center, Hiroshima University, Hiroshima, Japan
| | - Yizhou Zhang
- Department of Gastroenterology and Metabolism, Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.,Liver Research Project Center, Hiroshima University, Hiroshima, Japan
| | - Grace Naswa Makokha
- Department of Gastroenterology and Metabolism, Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.,Liver Research Project Center, Hiroshima University, Hiroshima, Japan
| | - Md Zobaer Hasan
- Liver Research Project Center, Hiroshima University, Hiroshima, Japan
| | - Magot D Omokoko
- Liver Research Project Center, Hiroshima University, Hiroshima, Japan
| | - Kazuaki Chayama
- Department of Gastroenterology and Metabolism, Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.,Laboratory for Digestive Diseases, Center for Genomic Medicine, RIKEN, Hiroshima, Japan.,Liver Research Project Center, Hiroshima University, Hiroshima, Japan
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60
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Mathematical Modelling of Cation Transport and Regulation in Yeast. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 892:291-305. [DOI: 10.1007/978-3-319-25304-6_12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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61
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Li X, Yang W, Zou Y, Meng F, Deng C, Zhong Z. Efficacious delivery of protein drugs to prostate cancer cells by PSMA-targeted pH-responsive chimaeric polymersomes. J Control Release 2015; 220:704-14. [PMID: 26348387 DOI: 10.1016/j.jconrel.2015.08.058] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 08/22/2015] [Accepted: 08/31/2015] [Indexed: 12/31/2022]
Abstract
Protein drugs as one of the most potent biotherapeutics have a tremendous potential in cancer therapy. Their application is, nevertheless, restricted by absence of efficacious, biocompatible, and cancer-targeting nanosystems. In this paper, we report that 2-[3-[5-amino-1-carboxypentyl]-ureido]-pentanedioic acid (Acupa)-decorated pH-responsive chimaeric polymersomes (Acupa-CPs) efficiently deliver therapeutic proteins into prostate cancer cells. Acupa-CPs had a unimodal distribution with average sizes ranging from 157-175 nm depending on amounts of Acupa. They displayed highly efficient loading of both model proteins, bovine serum albumin (BSA) and cytochrome C (CC), affording high protein loading contents of 9.1-24.5 wt.%. The in vitro release results showed that protein release was markedly accelerated at mildly acidic pH due to the hydrolysis of acetal bonds in the vesicular membrane. CLSM and MTT studies demonstrated that CC-loaded Acupa10-CPs mediated efficient delivery of protein drugs into PSMA positive LNCaP cells leading to pronounced antitumor effect, in contrast to their non-targeting counterparts and free CC. Remarkably, granzyme B (GrB)-loaded Acupa10-CPs caused effective apoptosis of LNCaP cells with a low half-maximal inhibitory concentration (IC50) of 1.6 nM. Flow cytometry and CLSM studies using MitoCapture™ revealed obvious depletion of mitochondria membrane potential in LNCaP cells treated with GrB-loaded Acupa10-CPs. The preliminary in vivo experiments showed that Acupa-CPs had a long circulation time with an elimination phase half-life of 3.3h in nude mice. PSMA-targeted, pH-responsive, and chimaeric polymersomes have appeared as efficient protein nanocarriers for targeted prostate cancer therapy.
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Affiliation(s)
- Xiang Li
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, PR China
| | - Weijing Yang
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, PR China
| | - Yan Zou
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, PR China
| | - Fenghua Meng
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, PR China.
| | - Chao Deng
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, PR China
| | - Zhiyuan Zhong
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, PR China.
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Koetting MC, Peters JT, Steichen SD, Peppas NA. Stimulus-responsive hydrogels: Theory, modern advances, and applications. MATERIALS SCIENCE & ENGINEERING. R, REPORTS : A REVIEW JOURNAL 2015; 93:1-49. [PMID: 27134415 PMCID: PMC4847551 DOI: 10.1016/j.mser.2015.04.001] [Citation(s) in RCA: 543] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Over the past century, hydrogels have emerged as effective materials for an immense variety of applications. The unique network structure of hydrogels enables very high levels of hydrophilicity and biocompatibility, while at the same time exhibiting the soft physical properties associated with living tissue, making them ideal biomaterials. Stimulus-responsive hydrogels have been especially impactful, allowing for unprecedented levels of control over material properties in response to external cues. This enhanced control has enabled groundbreaking advances in healthcare, allowing for more effective treatment of a vast array of diseases and improved approaches for tissue engineering and wound healing. In this extensive review, we identify and discuss the multitude of response modalities that have been developed, including temperature, pH, chemical, light, electro, and shear-sensitive hydrogels. We discuss the theoretical analysis of hydrogel properties and the mechanisms used to create these responses, highlighting both the pioneering and most recent work in all of these fields. Finally, we review the many current and proposed applications of these hydrogels in medicine and industry.
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Affiliation(s)
- Michael C. Koetting
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, United States
- Institute for Biomaterials, Drug Delivery, and Regenerative Medicine, The University of Texas at Austin, Austin, TX 78712, United States
| | - Jonathan T. Peters
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, United States
- Institute for Biomaterials, Drug Delivery, and Regenerative Medicine, The University of Texas at Austin, Austin, TX 78712, United States
| | - Stephanie D. Steichen
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, United States
- Institute for Biomaterials, Drug Delivery, and Regenerative Medicine, The University of Texas at Austin, Austin, TX 78712, United States
| | - Nicholas A. Peppas
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, United States
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, United States
- College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, United States
- Institute for Biomaterials, Drug Delivery, and Regenerative Medicine, The University of Texas at Austin, Austin, TX 78712, United States
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63
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Krishnan V, Gleason E. Nitric oxide releases Cl(-) from acidic organelles in retinal amacrine cells. Front Cell Neurosci 2015; 9:213. [PMID: 26106295 PMCID: PMC4459082 DOI: 10.3389/fncel.2015.00213] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 05/19/2015] [Indexed: 02/03/2023] Open
Abstract
Determining the factors regulating cytosolic Cl(-) in neurons is fundamental to our understanding of the function of GABA- and glycinergic synapses. This is because the Cl(-) distribution across the postsynaptic plasma membrane determines the sign and strength of postsynaptic voltage responses. We have previously demonstrated that nitric oxide (NO) releases Cl(-) into the cytosol from an internal compartment in both retinal amacrine cells and hippocampal neurons. Furthermore, we have shown that the increase in cytosolic Cl(-) is dependent upon a decrease in cytosolic pH. Here, our goals were to confirm the compartmental nature of the internal Cl(-) store and to test the hypothesis that Cl(-) is being released from acidic organelles (AO) such as the Golgi, endosomes or lysosomes. To achieve this, we made whole cell voltage clamp recordings from cultured chick retinal amacrine cells and used GABA-gated currents to track changes in cytosolic Cl(-). Our results demonstrate that intact internal proton gradients are required for the NO-dependent release of internal Cl(-). Furthermore, we demonstrate that increasing the pH of AO leads to release of Cl(-) into the cytosol. Intriguingly, the elevation of organellar pH results in a reversal in the effects of NO. These results demonstrate that cytosolic Cl(-) is closely linked to the regulation and maintenance of organellar pH and provide evidence that acidic compartments are the target of NO.
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Affiliation(s)
- Vijai Krishnan
- Department of Biological Sciences, Louisiana State University Baton Rouge, LA, USA
| | - Evanna Gleason
- Department of Biological Sciences, Louisiana State University Baton Rouge, LA, USA
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64
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Grasso G, Satriano C, Milardi D. A neglected modulator of insulin-degrading enzyme activity and conformation: The pH. Biophys Chem 2015; 203-204:33-40. [PMID: 26025789 DOI: 10.1016/j.bpc.2015.05.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 05/19/2015] [Accepted: 05/21/2015] [Indexed: 12/16/2022]
Abstract
Insulin-degrading enzyme (IDE), a ubiquitously expressed zinc metalloprotease, has multiple activities in addition to insulin degradation and its malfunction is believed to connect type 2 diabetes with Alzheimer's disease. IDE has been found in many different cellular compartments, where it may experience significant physio-pathological pH variations. However, the exact role of pH variations on the interplay between enzyme conformations, stability, oligomerization state and catalysis is not understood. Here, we use ESI mass spectrometry, atomic force microscopy, surface plasmon resonance and circular dichroism to investigate the structure-activity relationship of IDE at different pH values. We show that acidic pH affects the ability of the enzyme to bind the substrate and decrease the stability of the protein by inducing an α-helical bundle conformation with a concomitant dissociation of multi-subunit IDE assemblies into monomeric units and loss of activity. These effects suggest a major role played by electrostatic forces in regulating multi-subunit enzyme assembly and function. Our results clearly indicate a pH dependent coupling among enzyme conformation, assembly and stability and suggest that cellular acidosis can have a large effect on IDE oligomerization state, inducing an enzyme inactivation and an altered insulin degradation that could have an impact on insulin signaling.
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Affiliation(s)
- Giuseppe Grasso
- Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Viale Andrea Doria 6, 95125 Catania, Italy.
| | - Cristina Satriano
- Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Viale Andrea Doria 6, 95125 Catania, Italy
| | - Danilo Milardi
- Istituto Biostrutture e Bioimmagini, CNR, Via P. Gaifami 18, 95126 Catania, Italy
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65
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Chen P, Qiu M, Deng C, Meng F, Zhang J, Cheng R, Zhong Z. pH-Responsive chimaeric pepsomes based on asymmetric poly(ethylene glycol)-b-poly(l-leucine)-b-poly(l-glutamic acid) triblock copolymer for efficient loading and active intracellular delivery of doxorubicin hydrochloride. Biomacromolecules 2015; 16:1322-30. [PMID: 25759951 DOI: 10.1021/acs.biomac.5b00113] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
pH-Responsive chimaeric polypeptide-based polymersomes (refer to as pepsomes) were designed and developed from asymmetric poly(ethylene glycol)-b-poly(l-leucine)-b-poly(l-glutamic acid) (PEG-PLeu-PGA, PEG is longer than PGA) triblock copolymers for efficient encapsulation and triggered intracellular delivery of doxorubicin hydrochloride (DOX·HCl). PEG-PLeu-PGA was conveniently prepared by sequential ring-opening polymerization of l-leucine N-carboxyanhydride and γ-benzyl-l-glutamate N-carboxyanhydride using PEG-NH2 as an initiator followed by deprotection. Pepsomes formed from PEG-PLeu-PGA had unimodal distribution and small sizes of 64-71 nm depending on PLeu block lengths. Interestingly, these chimaeric pepsomes while stable at pH 7.4 were quickly disrupted at pH 5.0, likely due to alternation of ionization state of the carboxylic groups in PGA that shifts PGA blocks from hydrophilic and random coil structure into hydrophobic and α-helical structure. DOX·HCl could be actively loaded into the watery core of pepsomes with a high loading efficiency. Remarkably, the in vitro release studies revealed that release of DOX·HCl was highly dependent on pH, in which about 24.0% and 75.7% of drug was released at pH 7.4 and 5.0, respectively, at 37 °C in 24 h. MTT assays demonstrated that DOX·HCl-loaded pepsomes exhibited high antitumor activity, similar to free DOX·HCl in RAW 264.7 cells. Moreover, they were also potent toward drug-resistant MCF-7 cancer cells (MCF-7/ADR). Confocal microscopy studies showed that DOX·HCl-loaded pepsomes delivered and released drug into the cell nuclei of MCF-7/ADR cells in 4 h, while little DOX·HCl fluorescence was observed in MCF-7/ADR cells treated with free drug under otherwise the same conditions. These chimaeric pepsomes with facile synthesis, efficient drug loading, and pH-triggered drug release behavior are an attractive alternative to liposomes for targeted cancer chemotherapy.
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Affiliation(s)
- Peipei Chen
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, People's Republic of China
| | - Min Qiu
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, People's Republic of China
| | - Chao Deng
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, People's Republic of China
| | - Fenghua Meng
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, People's Republic of China
| | - Jian Zhang
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, People's Republic of China
| | - Ru Cheng
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, People's Republic of China
| | - Zhiyuan Zhong
- Biomedical Polymers Laboratory, and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, People's Republic of China
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66
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He M, Zhou J, Chen J, Zheng F, Wang D, Shi R, Guo Z, Wang H, Chen Q. Fe3O4@carbon@zeolitic imidazolate framework-8 nanoparticles as multifunctional pH-responsive drug delivery vehicles for tumor therapy in vivo. J Mater Chem B 2015; 3:9033-9042. [DOI: 10.1039/c5tb01830g] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Controlled drug release is a promising approach for cancer therapy due to its merits of reduced systemic toxicity and enhanced antitumor efficacy.
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Affiliation(s)
- Mengni He
- Hefei National Laboratory for Physical Sciences at Microscale
- Department of Materials Science & Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology
- CAS High Magnetic Field Laboratory
- University of Science and Technology of China
- Hefei 230026
| | - Jiajia Zhou
- Anhui Key Laboratory for Cellular Dynamics and Chemical Biology
- School of Life Sciences
- University of Science and Technology of China
- Hefei 230027
- China
| | - Jian Chen
- Hefei National Laboratory for Physical Sciences at Microscale
- Department of Materials Science & Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology
- CAS High Magnetic Field Laboratory
- University of Science and Technology of China
- Hefei 230026
| | - Fangcai Zheng
- Hefei National Laboratory for Physical Sciences at Microscale
- Department of Materials Science & Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology
- CAS High Magnetic Field Laboratory
- University of Science and Technology of China
- Hefei 230026
| | - Dongdong Wang
- Hefei National Laboratory for Physical Sciences at Microscale
- Department of Materials Science & Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology
- CAS High Magnetic Field Laboratory
- University of Science and Technology of China
- Hefei 230026
| | - Ruohong Shi
- Hefei National Laboratory for Physical Sciences at Microscale
- Department of Materials Science & Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology
- CAS High Magnetic Field Laboratory
- University of Science and Technology of China
- Hefei 230026
| | - Zhen Guo
- Anhui Key Laboratory for Cellular Dynamics and Chemical Biology
- School of Life Sciences
- University of Science and Technology of China
- Hefei 230027
- China
| | - Haibao Wang
- Radiology Department of the First Affiliated Hospital of Anhui Medical University
- Hefei 230022
- China
| | - Qianwang Chen
- Hefei National Laboratory for Physical Sciences at Microscale
- Department of Materials Science & Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology
- CAS High Magnetic Field Laboratory
- University of Science and Technology of China
- Hefei 230026
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67
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Ariño J, Aydar E, Drulhe S, Ganser D, Jorrín J, Kahm M, Krause F, Petrezsélyová S, Yenush L, Zimmermannová O, van Heusden GPH, Kschischo M, Ludwig J, Palmer C, Ramos J, Sychrová H. Systems biology of monovalent cation homeostasis in yeast: the translucent contribution. Adv Microb Physiol 2014; 64:1-63. [PMID: 24797924 DOI: 10.1016/b978-0-12-800143-1.00001-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Maintenance of monovalent cation homeostasis (mainly K(+) and Na(+)) is vital for cell survival, and cation toxicity is at the basis of a myriad of relevant phenomena, such as salt stress in crops and diverse human diseases. Full understanding of the importance of monovalent cations in the biology of the cell can only be achieved from a systemic perspective. Translucent is a multinational project developed within the context of the SysMO (System Biology of Microorganisms) initiative and focussed in the study of cation homeostasis using the well-known yeast Saccharomyces cerevisiae as a model. The present review summarize how the combination of biochemical, genetic, genomic and computational approaches has boosted our knowledge in this field, providing the basis for a more comprehensive and coherent vision of the role of monovalent cations in the biology of the cell.
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Affiliation(s)
- Joaquín Ariño
- Institut de Biotecnologia i Biomedicina & Dept. Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain.
| | - Ebru Aydar
- Faculty of Life Sciences and Computing, London Metropolitan University, London, United Kingdom
| | | | | | - Jesús Jorrín
- Department of Biochemistry and Molecular Biology, University of Córdoba, Córdoba, Spain
| | - Matthias Kahm
- RheinAhrCampus, University of Applied Sciences Koblenz, Remagen, Germany
| | | | - Silvia Petrezsélyová
- Institut de Biotecnologia i Biomedicina & Dept. Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Lynne Yenush
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Olga Zimmermannová
- Department of Membrane Transport, Institute of Physiology Academy of Sciences CR, Prague, Czech Republic
| | | | - Maik Kschischo
- RheinAhrCampus, University of Applied Sciences Koblenz, Remagen, Germany
| | | | - Chris Palmer
- Faculty of Life Sciences and Computing, London Metropolitan University, London, United Kingdom
| | - José Ramos
- Department of Microbiology, University of Córdoba, Córdoba, Spain
| | - Hana Sychrová
- Department of Membrane Transport, Institute of Physiology Academy of Sciences CR, Prague, Czech Republic
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68
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Meng F, Zhong Y, Cheng R, Deng C, Zhong Z. pH-sensitive polymeric nanoparticles for tumor-targeting doxorubicin delivery: concept and recent advances. Nanomedicine (Lond) 2014; 9:487-99. [PMID: 24746192 DOI: 10.2217/nnm.13.212] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Doxorubicin is a potent chemotherapeutic drug applied in the clinics for the treatment of various human cancers. It is typically administered as the hydrochloride salt or in liposomal forms, which are plagued with severe side effects. In recent years, pH-sensitive polymeric nanoparticles that are capable of retaining drug during circulation while actively releasing it at the tumor site and/or inside the target tumor cells have received an overwhelming interest for tumor-targeting cancer chemotherapy. This smart delivery approach has shown to elegantly resolve the in vivo stability versus intracellular drug release dilemma, as well as stealth versus tumor cell uptake dilemma. In this review, the concept and exciting new advances in pH-sensitive polymeric nanoparticles for doxorubicin delivery are presented and discussed.
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Affiliation(s)
- Fenghua Meng
- Biomedical Polymers Laboratory & Jiangsu Key Laboratory of Advanced Functional Polymer Design & Application, College of Chemistry, Chemical Engineering & Materials Science, Soochow University, Suzhou, 215123, People's Republic of China
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69
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Gadda G, Taibi A, Sisini F, Gambaccini M, Zamboni P, Ursino M. A new hemodynamic model for the study of cerebral venous outflow. Am J Physiol Heart Circ Physiol 2014; 308:H217-31. [PMID: 25398980 DOI: 10.1152/ajpheart.00469.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We developed a mathematical model of the cerebral venous outflow for the simulation of the average blood flows and pressures in the main drainage vessels of the brain. The main features of the model are that it includes a validated model for the simulation of the intracranial circulation and it accounts for the dependence of the hydraulic properties of the jugular veins with respect to the gravity field, which makes it an useful tool for the study of the correlations between extracranial blood redistributions and changes in the intracranial environment. The model is able to simulate the average pressures and flows in different points of the jugular ducts, taking into account the amount of blood coming from the anastomotic connections; simulate how the blood redistribution due to change of posture affects flows and pressures in specific points of the system; and simulate redistributions due to stenotic patterns. Sensitivity analysis to check the robustness of the model was performed. The model reproduces average physiologic behavior of the jugular, vertebral, and cerebral ducts in terms of pressures and flows. In fact, jugular flow drops from ∼11.7 to ∼1.4 ml/s in the passage from supine to standing. At the same time, vertebral flow increases from 0.8 to 3.4 ml/s, while cerebral blood flow, venous sinuses pressure, and intracranial pressure are constant around the average value of 12.5 ml/s, 6 mmHg, and 10 mmHg, respectively. All these values are in agreement with literature data.
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Affiliation(s)
- G Gadda
- Department of Physics and Earth Sciences, University of Ferrara, Ferrara, Italy;
| | - A Taibi
- Department of Physics and Earth Sciences, University of Ferrara, Ferrara, Italy
| | - F Sisini
- Department of Physics and Earth Sciences, University of Ferrara, Ferrara, Italy
| | - M Gambaccini
- Department of Physics and Earth Sciences, University of Ferrara, Ferrara, Italy
| | - P Zamboni
- Vascular Diseases Center, University of Ferrara, Ferrara, Italy; and
| | - M Ursino
- Department of Electrical, Electronic and Information Engineering, University of Bologna, Bologna, Italy
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70
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Quelch D, De Santis V, Strege A, Myers J, Wells L, Nutt D, Lingford-Hughes A, Parker C, Tyacke R. Influence of agonist induced internalization on [3H]Ro15-4513 binding-an application to imaging fluctuations in endogenous GABA with positron emission tomography. Synapse 2014; 69:60-5. [DOI: 10.1002/syn.21780] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 08/12/2014] [Accepted: 08/27/2014] [Indexed: 02/05/2023]
Affiliation(s)
- Darren Quelch
- Centre for Neuropsychopharmacology; Division of Brain Sciences; Imperial College; London UK
| | | | | | - James Myers
- Centre for Neuropsychopharmacology; Division of Brain Sciences; Imperial College; London UK
| | - Lisa Wells
- Imanova Centro for Imaging Sciences; London UK
| | - David Nutt
- Centre for Neuropsychopharmacology; Division of Brain Sciences; Imperial College; London UK
| | - Anne Lingford-Hughes
- Centre for Neuropsychopharmacology; Division of Brain Sciences; Imperial College; London UK
| | | | - Robin Tyacke
- Centre for Neuropsychopharmacology; Division of Brain Sciences; Imperial College; London UK
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71
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Lawson LS, Chan JW, Huser T. A highly sensitive nanoscale pH-sensor using Au nanoparticles linked by a multifunctional Raman-active reporter molecule. NANOSCALE 2014; 6:7971-7980. [PMID: 24902897 DOI: 10.1039/c3nr06277e] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Chemical sensing on the nanoscale has been breaking new ground since the discovery of surface enhanced Raman scattering (SERS). For nanoparticles, controlled particle aggregation is necessary to achieve the largest SERS enhancements. Therefore, aggregating agents such as salts or linker molecules are used in conjunction with chemically sensitive reporters in order to develop robust environmentally sensitive SERS probes. While salt-induced colloidal nanosphere aggregates have produced robust SERS signals, their variability in aggregate size contributes significantly to poor SERS signal reproducibility, which can complicate their use in in vitro cellular studies. Such systems often also lack reproducibility in spectral measurements between different nanoparticle clusters. Preaggregation of colloids via linkers followed by surface functionalization with reporter molecules results in the linker occupying valuable SERS hotspot volume which could otherwise be utilized by additional reporter molecules. Ideally, both functionalities should be obtained from a single molecule. Here, we report the use of 3,5-dimercaptobenzoic acid, a single multifunctional molecule that creates SERS hotspots via the controlled aggregation of nanoparticles, and also reports pH values. We show that 3,5-dimercaptobenzoic acid bound to Au nanospheres results in an excellent pH nanoprobe, producing very robust, and highly reproducible SERS signals that can report pH across the entire physiological range with excellent pH resolution. To demonstrate the efficacy of our novel pH reporters, these probes were also used to image both the particle and pH distribution in the cytoplasm of human induced pluripotent stem cells (hiPSCs).
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Affiliation(s)
- Latevi S Lawson
- NSF Center for Biophotonics Science and Technology, University of California, Davis, Sacramento, California 95817, USA
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72
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The influence of different cellular environments on PET radioligand binding: an application to D2/3-dopamine receptor imaging. Neuropharmacology 2014; 85:305-13. [PMID: 24910074 PMCID: PMC4109028 DOI: 10.1016/j.neuropharm.2014.05.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Revised: 05/01/2014] [Accepted: 05/26/2014] [Indexed: 01/10/2023]
Abstract
Various D2/3 receptor PET radioligands are sensitive to endogenous dopamine release in vivo. The Occupancy Model is generally used to interpret changes in binding observed in in vivo competition binding studies; an Internalisation Hypothesis may also contribute to these changes in signal. Extension of in vivo competition imaging to other receptor systems has been relatively unsuccessful. A greater understanding of the cellular processes underlying signal changes following endogenous neurotransmitter release may help translate this imaging paradigm to other receptor systems. To investigate the Internalisation Hypothesis we assessed the effects of different cellular environments, representative of those experienced by a receptor following agonist-induced internalisation, on the binding of three D2/3 PET ligands with previously reported sensitivities to endogenous dopamine in vivo, namely [3H]spiperone, [3H]raclopride and [3H]PhNO. Furthermore, we determined the contribution of each cellular compartment to total striatal binding for these D2/3 ligands. These studies suggest that sensitivity to endogenous dopamine release in vivo is related to a decrease in affinity in the endosomal environment compared with those found at the cell surface. In agreement with these findings we also demonstrate that ∼25% of total striatal binding for [3H]spiperone originates from sub-cellular, microsomal receptors, whereas for [3H]raclopride and [3H]PhNO, this fraction is lower, representing ∼14% and 17%, respectively. This pharmacological approach is fully translatable to other receptor systems. Assessment of affinity shifts in different cellular compartments may play a crucial role for understanding if a radioligand is sensitive to endogenous release in vivo, for not just the D2/3, but other receptor systems. The internalisation hypothesis was investigated in relation to D2/3 receptor PET ligand binding. KD and Bmax were determined for [3H]Raclopride, PhNO and Spiperone in different cellular buffers. The cellular distribution of [3H]Raclopride, PhNO and Spiperone binding was also determined. Reductions in KD were observed in the endosomal condition in the following order PhNO > Raclopride > Spiperone. KD shifts in different cellular compartments may predict sensitivity to neurotransmitter release in vivo.
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73
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Su C, Xia Y, Sun J, Wang N, Zhu L, Chen T, Huang Y, Liang D. Liposomes physically coated with peptides: preparation and characterization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:6219-6227. [PMID: 24826785 DOI: 10.1021/la501296r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Physically coating liposomes with peptides of desirable functions is an economic, versatile, and less time-consuming approach to prepare drug delivery vehicles. In this work, we designed three peptides-Ac-WWKKKGGNNN-NH2 (W2K3), Ac-WWRRRGGNNN-NH2(W2R3), Ac-WWGGGGGNNN-NH2(W2G3)-and studied their coating ability on negatively charged liposomes. It was found that the coating was mainly driven by the electrostatic interaction between the peptides' cationic side groups and the acidic lipids, which also mediated the "anchoring " of Trp residuals in the interfacial region of lipid bilayers. At the same conditions, the amount of the coated W2R3 was more than that of W2K3, but the stability of the liposome coated with W2R3 was deteriorated. This was caused by the delocalized charge of the guanidinium group of arginine. The coating of the peptide rendered the liposome pH-responsive behavior but did not prominently change the phase transition temperature. The liposome coated with peptides displayed appropriate pH/temperature dual responsive characteristics and was able to release the content in a controlled manner.
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Affiliation(s)
- Cuicui Su
- Beijing National Laboratory for Molecular Sciences and the Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
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74
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Brignone MS, Lanciotti A, Visentin S, De Nuccio C, Molinari P, Camerini S, Diociaiuti M, Petrini S, Minnone G, Crescenzi M, Laudiero LB, Bertini E, Petrucci TC, Ambrosini E. Megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal pH and protein trafficking in astrocytes: relevance to MLC disease pathogenesis. Neurobiol Dis 2014; 66:1-18. [PMID: 24561067 PMCID: PMC4003525 DOI: 10.1016/j.nbd.2014.02.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/20/2014] [Accepted: 02/10/2014] [Indexed: 11/28/2022] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy caused by mutations in the gene encoding MLC1, a membrane protein mainly expressed in astrocytes in the central nervous system. Although MLC1 function is unknown, evidence is emerging that it may regulate ion fluxes. Using biochemical and proteomic approaches to identify MLC1 interactors and elucidate MLC1 function we found that MLC1 interacts with the vacuolar ATPase (V-ATPase), the proton pump that regulates endosomal acidity. Because we previously showed that in intracellular organelles MLC1 directly binds Na, K-ATPase, which controls endosomal pH, we studied MLC1 endosomal localization and trafficking and MLC1 effects on endosomal acidity and function using human astrocytoma cells overexpressing wild-type (WT) MLC1 or MLC1 carrying pathological mutations. We found that WT MLC1 is abundantly expressed in early (EEA1(+), Rab5(+)) and recycling (Rab11(+)) endosomes and uses the latter compartment to traffic to the plasma membrane during hyposmotic stress. We also showed that WT MLC1 limits early endosomal acidification and influences protein trafficking in astrocytoma cells by stimulating protein recycling, as revealed by FITC-dextran measurement of endosomal pH and transferrin protein recycling assay, respectively. WT MLC1 also favors recycling to the plasma-membrane of the TRPV4 cation channel which cooperates with MLC1 to activate calcium influx in astrocytes during hyposmotic stress. Although MLC disease-causing mutations differentially affect MLC1 localization and trafficking, all the mutated proteins fail to influence endosomal pH and protein recycling. This study demonstrates that MLC1 modulates endosomal pH and protein trafficking suggesting that alteration of these processes contributes to MLC pathogenesis.
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Affiliation(s)
- Maria S Brignone
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Angela Lanciotti
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Sergio Visentin
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Chiara De Nuccio
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Paola Molinari
- Department of Pharmacology, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Serena Camerini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Marco Diociaiuti
- Department of Technology and Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Stefania Petrini
- Unit of Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Pediatric Research Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy.
| | - Gaetana Minnone
- Unit of Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Pediatric Research Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy.
| | - Marco Crescenzi
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Luisa Bracci Laudiero
- Unit of Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Pediatric Research Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy; Institute of Translational Pharmacology, CNR, Via del Fosso Cavaliere 100, 00133 Rome, Italy.
| | - Enrico Bertini
- Unit of Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Pediatric Research Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy.
| | - Tamara C Petrucci
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Elena Ambrosini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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75
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Doane T, Chomas A, Srinivasan S, Burda C. Observation and Photophysical Characterization of Silicon Phthalocyanine J-Aggregate Dimers in Aqueous Solutions. Chemistry 2014; 20:8030-9. [DOI: 10.1002/chem.201304885] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Indexed: 12/21/2022]
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76
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Pitt SJ, Lam AKM, Rietdorf K, Galione A, Sitsapesan R. Reconstituted human TPC1 is a proton-permeable ion channel and is activated by NAADP or Ca2+. Sci Signal 2014; 7:ra46. [PMID: 24847115 DOI: 10.1126/scisignal.2004854] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
NAADP potently triggers Ca2+ release from acidic lysosomal and endolysosomal Ca2+ stores. Human two-pore channels (TPC1 and TPC2), which are located on these stores, are involved in this process, but there is controversy over whether TPC1 and TPC2 constitute the Ca2+ release channels. We therefore examined the single-channel properties of human TPC1 after reconstitution into bilayers of controlled composition. We found that TPC1 was permeable not only to Ca2+ but also to monovalent cations and that permeability to protons was the highest (relative permeability sequence: H+ >> K+ > Na(+) ≥ Ca2+). NAADP or Ca2+ activated TPC1, and the presence of one of these ligands was required for channel activation. The endolysosome-located lipid phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2] had no effect on TPC1 open probability but significantly increased the relative permeability of Na+ to Ca2+ and of H+ to Ca2+. Furthermore, our data showed that, although both TPC1 and TPC2 are stimulated by NAADP, these channels differ in ion selectivity and modulation by Ca2+ and pH. We propose that NAADP triggers H+ release from lysosomes and endolysomes through activation of TPC1, but that the Ca2+ -releasing ability of TPC1 will depend on the ionic composition of the acidic stores and may be influenced by other regulators that affect TPC1 ion permeation.
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Affiliation(s)
- Samantha J Pitt
- School of Medicine, University of St Andrews, St Andrews KY16 9TF, UK
| | - Andy K M Lam
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Katja Rietdorf
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Rebecca Sitsapesan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
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77
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Blatt MR, Wang Y, Leonhardt N, Hills A. Exploring emergent properties in cellular homeostasis using OnGuard to model K+ and other ion transport in guard cells. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:770-8. [PMID: 24268743 PMCID: PMC4030602 DOI: 10.1016/j.jplph.2013.09.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 09/02/2013] [Accepted: 09/03/2013] [Indexed: 05/17/2023]
Abstract
It is widely recognized that the nature and characteristics of transport across eukaryotic membranes are so complex as to defy intuitive understanding. In these circumstances, quantitative mathematical modeling is an essential tool, both to integrate detailed knowledge of individual transporters and to extract the properties emergent from their interactions. As the first, fully integrated and quantitative modeling environment for the study of ion transport dynamics in a plant cell, OnGuard offers a unique tool for exploring homeostatic properties emerging from the interactions of ion transport, both at the plasma membrane and tonoplast in the guard cell. OnGuard has already yielded detail sufficient to guide phenotypic and mutational studies, and it represents a key step toward 'reverse engineering' of stomatal guard cell physiology, based on rational design and testing in simulation, to improve water use efficiency and carbon assimilation. Its construction from the HoTSig libraries enables translation of the software to other cell types, including growing root hairs and pollen. The problems inherent to transport are nonetheless challenging, and are compounded for those unfamiliar with conceptual 'mindset' of the modeler. Here we set out guidelines for the use of OnGuard and outline a standardized approach that will enable users to advance quickly to its application both in the classroom and laboratory. We also highlight the uncanny and emergent property of OnGuard models to reproduce the 'communication' evident between the plasma membrane and tonoplast of the guard cell.
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Affiliation(s)
- Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Bower Building, Glasgow G12 8QQ, UK.
| | - Yizhou Wang
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Bower Building, Glasgow G12 8QQ, UK
| | - Nathalie Leonhardt
- Laboratoire de Biologie du Développement des Plantes, UMR 7265, CNRS/CEA/Aix-Marseille Université, Saint-Paul-lez-Durance, France
| | - Adrian Hills
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Bower Building, Glasgow G12 8QQ, UK
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78
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Varela ARP, Gonçalves da Silva AMPS, Fedorov A, Futerman AH, Prieto M, Silva LC. Influence of intracellular membrane pH on sphingolipid organization and membrane biophysical properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:4094-4104. [PMID: 24654655 DOI: 10.1021/la5003397] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Glucosylceramide (GlcCer) is a signaling lipid involved in the regulation of several cellular processes. It is present in different organelles, including the plasma membrane, Golgi apparatus, endoplasmic reticulum, and lysosomes. Accordingly, GlcCer is exposed to different pH environments in each organelle, which may lead to alterations in its properties and lateral organization and subsequent biological outcome. In this study, we addressed the effect of pH on the biophysical behavior of this lipid and other structurally related sphingolipids (SLs). Membranes composed of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) and C16-GlcCer, sphingomyelin, and different acyl chain ceramides were characterized by fluorescence spectroscopy, confocal microscopy, and surface pressure-area measurements under neutral and acidic conditions. The results show that changing the pH from 7.4 to 5.5 has a larger impact on C16-GlcCer-containing membranes compared to other SLs. In addition, acidification mainly affects the organization and packing properties of the GlcCer-enriched gel phase, suggesting that the interactions established by the glucose moiety, in the GlcCer molecule, are those most affected by the increase in the acidity. These results further highlight the role of GlcCer as a modulator of membrane biophysical properties and will possibly contribute to the understanding of its biological function in different organelles.
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Affiliation(s)
- Ana R P Varela
- iMed.UL, Faculdade de Farmácia, Universidade de Lisboa , Avenida Professor Gama Pinto, 1649-003 Lisboa, Portugal
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79
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Bera R, Dey A, Chakrabarty D. Synthesis, Characterization, and drug release study of acrylamide-co-itaconic acid based smart hydrogel. POLYM ENG SCI 2014. [DOI: 10.1002/pen.23874] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Rabin Bera
- Department of Polymer Science and Technology; University of Calcutta; Kolkata 700009 India
| | - Ayan Dey
- Department of Polymer Science and Technology; University of Calcutta; Kolkata 700009 India
| | - Debabrata Chakrabarty
- Department of Polymer Science and Technology; University of Calcutta; Kolkata 700009 India
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80
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Yang XG, Wang K. Chemical, biochemical, and biological behaviors of vanadate and its oligomers. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2014; 54:1-18. [PMID: 24420708 DOI: 10.1007/978-3-642-41004-8_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Vanadate is widely used as an inhibitor of protein tyrosine phosphatases (PTPase) and is routinely applied in cell lysis buffers or immunoprecipitations of phosphotyrosyl proteins. Additionally, vanadate has been extensively studied for its antidiabetic and anticancer effects. In most studies, orthovanadate or metavanadate was used as the starting compound, whereas these "vanadate" solutions may contain more or less oligomerized species. Whether and how different species of vanadium compounds formed in the biological media exert specific biological effect is still a mystery. In the present commentary, we focus on the chemical, biochemical, and biological behaviors of vanadate. On the basis of species formation of vanadate in chemical and biological systems, we compared the biological effects and working mechanism of monovanadate with that of its oligomers, especially the decamer. We propose that different oligomers may exert a specific biological effect, which depends on their structures and the context of the cell types, by different modes of action.
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Affiliation(s)
- Xiao-Gai Yang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, People's Republic of China
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81
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Henderson IM, Adams PG, Montaño GA, Paxton WF. Ionic effects on the behavior of thermoresponsive PEO-PNIPAAm block copolymers. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/polb.23444] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Ian M. Henderson
- Center for Integrated Nanotechnologies; Sandia National Laboratories; Albuquerque New Mexico 87185
| | - Peter G. Adams
- Center for Integrated Nanotechnologies; Los Alamos National Laboratory; Los Alamos New Mexico 87544
| | - Gabriel A. Montaño
- Center for Integrated Nanotechnologies; Los Alamos National Laboratory; Los Alamos New Mexico 87544
| | - Walter F. Paxton
- Center for Integrated Nanotechnologies; Sandia National Laboratories; Albuquerque New Mexico 87185
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82
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Yin H, Kang HC, Huh KM, Bae YH. Effects of cholesterol incorporation on the physicochemical, colloidal, and biological characteristics of pH-sensitive AB₂ miktoarm polymer-based polymersomes. Colloids Surf B Biointerfaces 2013; 116:128-37. [PMID: 24463148 DOI: 10.1016/j.colsurfb.2013.12.041] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 11/24/2013] [Accepted: 12/20/2013] [Indexed: 10/25/2022]
Abstract
In our previous study, a histidine-based AB2 miktoarm polymer, methoxy poly(ethylene glycol)-b-poly(l-histidine)2 (mPEG-b-(PolyHis)2), was designed to construct pH-sensitive polymersomes that transform in acidic pH; the polymer self-assembles into a structure that mimics phospholipids. In this study, the polymersomes further imitated liposomes due to the incorporation of cholesterol (CL). The hydrodynamic radii of the polymersomes increased with increasing CLwt% (e.g., 70 nm for 0 wt% vs. 91 nm for 1 wt%), resulting in an increased capacity for encapsulating hydrophilic drugs (e.g., 0.92 μL/mg for 0 wt% vs. 1.42 μL/mg for 1 wt%). The CL incorporation enhanced the colloidal stability of the polymersomes in the presence of serum protein and retarded their payload release. However, CL-incorporating polymersomes still demonstrated accelerated release of a hydrophilic dye (e.g., 5(6)-carboxyfluorescein (CF)) below pH 6.8 without losing their desirable pH sensitivity. CF-loaded CL-incorporating polymersomes showed better cellular internalization than the hydrophilic CF, whereas doxorubicin (DOX)-loaded CL-incorporating polymersomes presented similar or somewhat lower anti-tumor effects than free hydrophobic DOX. The findings suggest that CL-incorporating mPEG-b-(PolyHis)2-based polymersomes may have potential for intracellular drug delivery of chemical drugs due to their improved colloidal stability, lower drug loss during circulation, acidic pH-induced drug release, and endosomal disruption.
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Affiliation(s)
- Haiqing Yin
- Department of Pharmaceutics and Pharmaceutical Chemistry, The University of Utah, 30 S 2000 E, Room 2972, Salt Lake City, UT 84112, USA
| | - Han Chang Kang
- Department of Pharmacy and Integrated Research Institute of Pharmaceutical Sciences, College of Pharmacy, The Catholic University of Korea, 43 Jibong-ro, Wonmi-gu, Bucheon-si, Gyeonggi-do 420-743, Republic of Korea
| | - Kang Moo Huh
- Department of Polymer Science and Engineering, Chungnam National University, 220 Gung-dong, Yuseong-gu, Daejeon 305-764, Republic of Korea
| | - You Han Bae
- Department of Pharmaceutics and Pharmaceutical Chemistry, The University of Utah, 30 S 2000 E, Room 2972, Salt Lake City, UT 84112, USA; Utah-Inha Drug Delivery Systems (DDS) and Advanced Therapeutics Research Center, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, Republic of Korea.
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83
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Abstract
Lysosomes must maintain an acidic luminal pH to activate hydrolytic enzymes and degrade internalized macromolecules. Acidification requires the vacuolar-type H(+)-ATPase to pump protons into the lumen and a counterion flux to neutralize the membrane potential created by proton accumulation. Early experiments suggested that the counterion was chloride, and more recently a pathway consistent with the ClC-7 Cl(-)/H(+) antiporter was identified. However, reports that the steady-state luminal pH is unaffected in ClC-7 knockout mice raise questions regarding the identity of the carrier and the counterion. Here, we measure the current-voltage characteristics of a mammalian ClC-7 antiporter, and we use its transport properties, together with other key ion regulating elements, to construct a mathematical model of lysosomal pH regulation. We show that results of in vitro lysosome experiments can only be explained by the presence of ClC-7, and that ClC-7 promotes greater acidification than Cl(-), K(+), or Na(+) channels. Our models predict strikingly different lysosomal K(+) dynamics depending on the major counterion pathways. However, given the lack of experimental data concerning acidification in vivo, the model cannot definitively rule out any given mechanism, but the model does provide concrete predictions for additional experiments that would clarify the identity of the counterion and its carrier.
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Affiliation(s)
- Yoichi Ishida
- Department of History and Philosophy of Science, University of Pittsburgh, Pittsburgh, PA 15260, USA
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84
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Lind U, Alm Rosenblad M, Wrange AL, Sundell KS, Jonsson PR, André C, Havenhand J, Blomberg A. Molecular characterization of the α-subunit of Na⁺/K⁺ ATPase from the euryhaline barnacle Balanus improvisus reveals multiple genes and differential expression of alternative splice variants. PLoS One 2013; 8:e77069. [PMID: 24130836 PMCID: PMC3793950 DOI: 10.1371/journal.pone.0077069] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 09/06/2013] [Indexed: 01/28/2023] Open
Abstract
The euryhaline bay barnacle Balanus improvisus has one of the broadest salinity tolerances of any barnacle species. It is able to complete its life cycle in salinities close to freshwater (3 PSU) up to fully marine conditions (35 PSU) and is regarded as one of few truly brackish-water species. Na+/K+ ATPase (NAK) has been shown to be important for osmoregulation when marine organisms are challenged by changing salinities, and we therefore cloned and examined the expression of different NAKs from B. improvisus. We found two main gene variants, NAK1 and NAK2, which were approximately 70% identical at the protein level. The NAK1 mRNA existed in a long and short variant with the encoded proteins differing only by 27 N-terminal amino acids. This N-terminal stretch was coded for by a separate exon, and the two variants of NAK1 mRNAs appeared to be created by alternative splicing. We furthermore showed that the two NAK1 isoforms were differentially expressed in different life stages and in various tissues of adult barnacle, i.e the long isoform was predominant in cyprids and in adult cirri. In barnacle cyprid larvae that were exposed to a combination of different salinities and pCO2 levels, the expression of the long NAK1 mRNA increased relative to the short in low salinities. We suggest that the alternatively spliced long variant of the Nak1 protein might be of importance for osmoregulation in B. improvisus in low salinity conditions.
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Affiliation(s)
- Ulrika Lind
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Magnus Alm Rosenblad
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Anna-Lisa Wrange
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Kristina S. Sundell
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Per R. Jonsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Carl André
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Jonathan Havenhand
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Anders Blomberg
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
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85
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Berezin SK. Theoretical modelling of anion transport in liposomes: electrogenic anion exchange as a new paradigm in supramolecular chemistry. Supramol Chem 2013. [DOI: 10.1080/10610278.2013.782099] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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86
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Abstract
Luminal acidification is of pivotal importance for the physiology of the secretory and endocytic pathways and its diverse trafficking events. Acidification by the proton-pumping V-ATPase requires charge compensation by counterion currents that are commonly attributed to chloride. The molecular identification of intracellular chloride transporters and the improvement of methodologies for measuring intraorganellar pH and chloride have facilitated the investigation of the physiology of vesicular chloride transport. New data question the requirement of chloride for pH regulation of various organelles and furthermore ascribe functions to chloride that are beyond merely electrically shunting the proton pump. This review surveys the currently established and proposed intracellular chloride transporters and gives an overview of membrane-trafficking steps that are affected by the perturbation of chloride transport. Finally, potential mechanisms of membrane-trafficking modulation by chloride are discussed and put into the context of organellar ion homeostasis in general.
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Affiliation(s)
- Tobias Stauber
- Physiology and Pathology of Ion Transport, Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin, 13125 Berlin, Germany.
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87
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Quelch DR, Parker CA, Nutt DJ, Tyacke RJ, Erritzoe D. Influence of different cellular environments on [(3)H]DASB radioligand binding. Synapse 2012; 66:1035-9. [PMID: 22927261 DOI: 10.1002/syn.21605] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 08/16/2012] [Indexed: 11/06/2022]
Affiliation(s)
- D R Quelch
- Neuropsychopharmacology Unit, Division of Experimental Medicine, Imperial College London, London W120NN, United Kingdom.
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88
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Insights into avian influenza virus pathogenicity: the hemagglutinin precursor HA0 of subtype H16 has an alpha-helix structure in its cleavage site with inefficient HA1/HA2 cleavage. J Virol 2012; 86:12861-70. [PMID: 22993148 DOI: 10.1128/jvi.01606-12] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
With a new serotype (H17) of hemagglutinin (HA) recently being discovered, there are now 17 serotypes (H1 to H17) of influenza A viruses in total. It is believed that HA is initially expressed as a precursor of HA0 and then cleaved into HA1 and HA2, forming a disulfide bond-linked complex, for its full function. Structural data show that a loop structure exists in the cleavage site between HA1 and HA2, and this flexible loop is crucial for the efficient cleavage of HA0. Here, the crystal structures of H16 (a low-pathogenicity avian influenza virus) in their HA0 form (H16HA0) have been solved at 1.7-Å and 2.0-Å resolutions. To our surprise, an α-helix element in the cleavage site which inserts into the negatively charged cavity with the key residue R329 hidden behind the helix was observed. In vitro trypsin cleavage experiments demonstrated inefficient cleavage of H16HA0 under both neutral and low-pH conditions. The results provide new insights into influenza A virus pathogenicity; both the relatively stable α-helix structure in the flexible cleavage loop and inaccessibility of the cleavage site likely contribute to the low pathogenicity of avian influenza A virus. Furthermore, compared to all of the HAs whose structures have been solved, H16 is a good reference for assigning the HA subtypes into two groups on the basis of the three-dimensional structure, which is consistent with the phylogenetic grouping. We conclude that in light of the current H16HA0 structure, the natural α-helix element might provide a new opportunity for influenza virus inhibitor design.
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89
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Abstract
Most organelles within the exocytic and endocytic pathways typically acidify their interiors, a phenomenon that is known to be crucial for their optimal functioning in eukaryotic cells. This review highlights recent advances in our understanding of how Golgi acidity is maintained and regulated, and how its misregulation contributes to organelle dysfunction and disease. Both its biosynthetic products (glycans) and protein-sorting events are highly sensitive to changes in Golgi luminal pH and are affected in certain human disease states such as cancers and cutis laxa. Other potential disease states that are caused by, or are associated with, Golgi pH misregulation will also be discussed.
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Affiliation(s)
- Antti Rivinoja
- Department of Biochemistry, University of Oulu, Oulu, Finland
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90
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Freeman EC, Weiland LM, Meng WS. Modeling the proton sponge hypothesis: examining proton sponge effectiveness for enhancing intracellular gene delivery through multiscale modeling. JOURNAL OF BIOMATERIALS SCIENCE. POLYMER EDITION 2012; 24:398-416. [PMID: 23565683 PMCID: PMC3623018 DOI: 10.1080/09205063.2012.690282] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Dendrimers have been proposed as therapeutic gene delivery platforms. Their superior transfection efficiency is attributed to their ability to buffer the acidification of the endosome and attach to the nucleic acids. For effective transfection, the strategy is to synthesize novel dendrimers that optimize both of these traits, but the prediction of the buffering behavior in the endosome remains elusive. It is suggested that buffering dendrimers induce an osmotic pressure sufficient to rupture the endosome and release nucleic acids, which forms to sequestrate most internalized exogenous materials. Presented here are the results of a computational study modeling osmotically driven endosome burst or the 'proton sponge effect.' The approach builds on previous cellular simulation efforts by linking the previous model with a sponge protonation model, then observing the impact on endosomal swelling and acidification. Calibrated and validated using reported experimental data, the simulations offer insights into defining the properties of suitable dendrimers for enhancing gene delivery as a function of polymer structure.
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Affiliation(s)
- Eric C Freeman
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, PA, USA.
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91
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A hypothetical model of cargo-selective rab recruitment during organelle maturation. Cell Biochem Biophys 2012; 63:59-71. [PMID: 22328341 DOI: 10.1007/s12013-012-9341-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Rabs constitute a group of small GTPases that confer directionality to intracellular vesicle transport by promoting on the membrane of transport vesicles in the formation of specific protein complexes allowing for efficient fusion with a selected set of target organelles. The molecular mechanism controlling recruitment of the correct Rab at the right time is not fully understood. We propose a model according to which the residence time of a given Rab on the membrane of an organelle is determined by its transient trapping into a Rab effector complex (REC) composed of cargo receptor, SNAREs and further effectors. The stability of REC is controlled by the conformational state of the receptor which may change due to binding and release of cargo or changes in the luminal ion milieu. We use a conceptual mathematical model to calculate temporal changes in the Rab decoration of an organelle brought about by exchange with a cytosolic pool of Rabs or alternatively by budding and uptake of Rab-carrying vesicles. Considering the time-dependent drop in pH as one crucial factor for the conformational change of endocytic cargo receptors, our model provides a good quantitative description of the switch from Rab5 to Rab7 during the early-to-late endosome transition and correctly explains the arrest of this transition at insufficient luminal acidification. Model simulations suggest that a switch from one Rab to another may be continuous or abrupt. We discuss mechanisms, e.g. specific signalling pathways, which may restore an arrested organelle maturation.
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92
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Müller DN, Binger KJ, Riediger F. Prorenin receptor regulates more than the renin-angiotensin system. Ann Med 2012; 44 Suppl 1:S43-8. [PMID: 22713148 DOI: 10.3109/07853890.2012.660496] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The (pro)renin receptor (PRR) was initially believed to be a contributor to the pathogenesis of cardiovascular diseases via the amplification of renin- or prorenin-induced angiotensin (Ang) formation. However, a recent paradigm shift suggests a new role for PRR, separate from the renin-angiotensin system (RAS), in contributing to cellular homeostasis. Specifically, PRR is thought to be essential for vacuolar H(+) -ATPase (V-ATPase) activity and acts as an adaptor between the V-ATPase and the Wnt signalling pathway. Recent PRR conditional knock-out studies have confirmed this link between V-ATPase and PRR, with deletion resulting in the accumulation of autophagic vacuoles and animal lethality. The molecular mechanism by which PRR contributes to V-ATPase activity, and whether multiple signalling pathways are affected by PRR loss, is currently unknown. Additionally, cleavage by furin at a single site within full-length PRR results in the production of a soluble form of the receptor, which is detectable in plasma. Soluble PRR is hypothesized to bind to specific ligands and receptors and mediate signal transduction pathways. Understanding the physiological function of full-length and soluble PRR will be important for establishing its role in pathology.
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Affiliation(s)
- Dominik N Müller
- Experimental and Clinical Research Center (ECRC), an institutional cooperation between Charité Medical Faculty and MDC, Berlin, Germany.
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93
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Melkikh AV, Seleznev VD. Mechanisms and models of the active transport of ions and the transformation of energy in intracellular compartments. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 109:33-57. [DOI: 10.1016/j.pbiomolbio.2012.04.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2011] [Revised: 04/23/2012] [Accepted: 04/25/2012] [Indexed: 11/26/2022]
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94
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Lagache T, Danos O, Holcman D. Modeling the step of endosomal escape during cell infection by a nonenveloped virus. Biophys J 2012; 102:980-9. [PMID: 22404920 DOI: 10.1016/j.bpj.2011.12.037] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 12/21/2011] [Accepted: 12/21/2011] [Indexed: 11/27/2022] Open
Abstract
Widely disparate viruses enter the host cell through an endocytic pathway and travel the cytoplasm inside an endosome. For the viral genetic material to be delivered into the cytoplasm, these viruses have to escape the endosomal compartment, an event triggered by the conformational changes of viral endosomolytic proteins. We focus here on small nonenveloped viruses such as adeno-associated viruses, which contain few penetration proteins. The first time a penetration protein changes conformation defines the slowest timescale responsible for the escape. To evaluate this time, we construct what to our knowledge is a novel biophysical model based on a stochastic approach that accounts for the small number of proteins, the endosomal maturation, and the protease activation dynamics. We show that the escape time increases with the endosomal size, whereas decreasing with the number of viral particles inside the endosome. We predict that the optimal escape probability is achieved when the number of proteases in the endosome is in the range of 250-350, achieved for three viral particles.
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Affiliation(s)
- Thibault Lagache
- Group of Computational Biology and Applied Mathematics, Institut de Biologie de l'Ecole Normale Supérieure, Paris, France
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95
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Budzinski KL, Zeigler M, Fujimoto BS, Bajjalieh SM, Chiu DT. Measurements of the acidification kinetics of single SynaptopHluorin vesicles. Biophys J 2012; 101:1580-9. [PMID: 21961583 DOI: 10.1016/j.bpj.2011.08.032] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 08/15/2011] [Accepted: 08/19/2011] [Indexed: 11/29/2022] Open
Abstract
Uptake of neurotransmitters into synaptic vesicles is driven by the proton gradient established across the vesicle membrane. The acidification of synaptic vesicles, therefore, is a crucial component of vesicle function. Here we present measurements of acidification rate constants from isolated, single synaptic vesicles. Vesicles were purified from mice expressing a fusion protein termed SynaptopHluorin created by the fusion of VAMP/synaptobrevin to the pH-sensitive super-ecliptic green fluorescent protein. We calibrated SynaptopHluorin fluorescence to determine the relationship between fluorescence intensity and internal vesicle pH, and used these values to measure the rate constant of vesicle acidification. We also measured the effects of ATP, glutamate, and chloride on acidification. We report acidification time constants of 500 ms to 1 s. The rate of acidification increased with increasing extravesicular concentrations of ATP and glutamate. These data provide an upper and a lower bound for vesicle acidification and indicate that vesicle readiness can be regulated by changes in energy and transmitter availability.
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Affiliation(s)
- Kristi L Budzinski
- Department of Chemistry, University of Washington, Seattle, Washington, USA
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96
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Yin H, Kang HC, Huh KM, Bae YH. Biocompatible, pH-sensitive AB(2) Miktoarm Polymer-Based Polymersomes: Preparation, Characterization, and Acidic pH-Activated Nanostructural Transformation. ACTA ACUST UNITED AC 2012; 22:91968-19178. [PMID: 23002330 DOI: 10.1039/c2jm33750a] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Motivated by the limitations of liposomal drug delivery systems, we designed a novel histidine-based AB(2)-miktoarm polymer (mPEG-b-(polyHis)(2)) equipped with a phospholipid-mimic structure, low cytotoxicity, and pH-sensitivity. Using "core-first" click chemistry and ring-opening polymerization, mPEG(2kDa)-b-(polyHis(29kDa))(2) was successfully synthesized with a narrow molecular weight distribution (1.14). In borate buffer (pH 9), the miktoarm polymer self-assembled to form a nano-sized polymersome with a hydrodynamic radius of 70.2 nm and a very narrow size polydispersity (0.05). At 4.2 µmol/mg polymer, mPEG(2kDa)-b-(polyHis(29kDa))(2) strongly buffered against acidification in the endolysosomal pH range and exhibited low cytotoxicity on a 5 d exposure. Below pH 7.4 the polymersome transitioned to cylindrical micelles, spherical micelles, and finally unimers as the pH was decreased. The pH-induced structural transition of mPEG(2kDa)-b-(polyHis(29kDa))(2) nanostructures may be caused by the increasing hydrophilic weight fraction of mPEG(2kDa)-b-(polyHis(29kDa))(2) and can help to disrupt the endosomal membrane through proton buffering and membrane fusion of mPEG(2kDa)-b-(polyHis(29kDa))(2). In addition, a hydrophilic model dye, 5(6)-carboxyfluorescein encapsulated into the aqueous lumen of the polymersome showed a slow, sustained release at pH 7.4 but greatly accelerated release below pH 6.8, indicating a desirable pH sensitivity of the system in the range of endosomal pH. Therefore, this polymersome that is based on a biocompatible histidine-based miktoarm polymer and undergoes acid-induced transformations could serve as a drug delivery vehicle for chemical and biological drugs.
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Affiliation(s)
- Haiqing Yin
- Department of Pharmaceutics and Pharmaceutical Chemistry, The University of Utah, 421 Wakara Way, Suite 318, Salt Lake City, Utah 84108, USA
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97
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Sun Y, Chen XY, Zhu YJ, Liu PF, Zhu MJ, Duan YR. Synthesis of calcium phosphate/GPC-mPEG hybrid porous nanospheres for drug delivery to overcome multidrug resistance in human breast cancer. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm15586a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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98
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Drescher D, Kneipp J. Nanomaterials in complex biological systems: insights from Raman spectroscopy. Chem Soc Rev 2012; 41:5780-99. [DOI: 10.1039/c2cs35127g] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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99
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Molecular mechanisms of endolysosomal Ca2+ signalling in health and disease. Biochem J 2011; 439:349-74. [PMID: 21992097 DOI: 10.1042/bj20110949] [Citation(s) in RCA: 295] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Endosomes, lysosomes and lysosome-related organelles are emerging as important Ca2+ storage cellular compartments with a central role in intracellular Ca2+ signalling. Endocytosis at the plasma membrane forms endosomal vesicles which mature to late endosomes and culminate in lysosomal biogenesis. During this process, acquisition of different ion channels and transporters progressively changes the endolysosomal luminal ionic environment (e.g. pH and Ca2+) to regulate enzyme activities, membrane fusion/fission and organellar ion fluxes, and defects in these can result in disease. In the present review we focus on the physiology of the inter-related transport mechanisms of Ca2+ and H+ across endolysosomal membranes. In particular, we discuss the role of the Ca2+-mobilizing messenger NAADP (nicotinic acid adenine dinucleotide phosphate) as a major regulator of Ca2+ release from endolysosomes, and the recent discovery of an endolysosomal channel family, the TPCs (two-pore channels), as its principal intracellular targets. Recent molecular studies of endolysosomal Ca2+ physiology and its regulation by NAADP-gated TPCs are providing exciting new insights into the mechanisms of Ca2+-signal initiation that control a wide range of cellular processes and play a role in disease. These developments underscore a new central role for the endolysosomal system in cellular Ca2+ regulation and signalling.
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100
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Kordium VA, Irodov DM, Maslova OO, Ruban TA, Sukhorada EM, Andrienko VI, Shuvalova NS, Likhachova LI, Shpilova SP. Fundamental biology reached a plateau – development of ideas. ACTA ACUST UNITED AC 2011. [DOI: 10.7124/bc.00011b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- V. A. Kordium
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - D. M. Irodov
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - O. O. Maslova
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - T. A. Ruban
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - E. M. Sukhorada
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - V. I. Andrienko
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - N. S. Shuvalova
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - L. I. Likhachova
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - S. P. Shpilova
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
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