51
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A NBD-based simple but effective fluorescent pH probe for imaging of lysosomes in living cells. Anal Chim Acta 2016; 920:86-93. [DOI: 10.1016/j.aca.2016.03.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 03/11/2016] [Accepted: 03/16/2016] [Indexed: 12/13/2022]
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52
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Tanaka H, Sato Y, Harashima H, Akita H. Cellular environment-responsive nanomaterials for use in gene and siRNA delivery: molecular design for biomembrane destabilization and intracellular collapse. Expert Opin Drug Deliv 2016; 13:1015-27. [DOI: 10.1517/17425247.2016.1154531] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Hiroki Tanaka
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Yusuke Sato
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | | | - Hidetaka Akita
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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53
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Macri C, Wang F, Tasset I, Schall N, Page N, Briand JP, Cuervo AM, Muller S. Modulation of deregulated chaperone-mediated autophagy by a phosphopeptide. Autophagy 2016; 11:472-86. [PMID: 25719862 PMCID: PMC4502742 DOI: 10.1080/15548627.2015.1017179] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
The P140 peptide, a 21-mer linear peptide (sequence 131-151) generated from the spliceosomal SNRNP70/U1-70K protein, contains a phosphoserine residue at position 140. It significantly ameliorates clinical manifestations in autoimmune patients with systemic lupus erythematosus and enhances survival in MRL/lpr lupus-prone mice. Previous studies showed that after P140 treatment, there is an accumulation of autophagy markers sequestosome 1/p62 and MAP1LC3-II in MRL/lpr B cells, consistent with a downregulation of autophagic flux. We now identify chaperone-mediated autophagy (CMA) as a target of P140 and demonstrate that its inhibitory effect on CMA is likely tied to its ability to alter the composition of HSPA8/HSC70 heterocomplexes. As in the case of HSPA8, expression of the limiting CMA component LAMP2A, which is increased in MRL/lpr B cells, is downregulated after P140 treatment. We also show that P140, but not the unphosphorylated peptide, uses the clathrin-dependent endo-lysosomal pathway to enter into MRL/lpr B lymphocytes and accumulates in the lysosomal lumen where it may directly hamper lysosomal HSPA8 chaperoning functions, and also destabilize LAMP2A in lysosomes as a result of its effect on HSP90AA1. This dual effect may interfere with the endogenous autoantigen processing and loading to major histocompatibility complex class II molecules and as a consequence, lead to lower activation of autoreactive T cells. These results shed light on mechanisms by which P140 can modulate lupus disease and exert its tolerogenic activity in patients. The unique selective inhibitory effect of the P140 peptide on CMA may be harnessed in other pathological conditions in which reduction of CMA activity would be desired.
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Key Words
- ALF, artificial lysosomal fluid
- APC, antigen-presenting cell
- B lymphocytes
- CMA, chaperone-mediated autophagy
- CPZ: chlorpromazine
- CTSD, cathepsin D
- CoIP, coimmunoprecipitation
- DAPI, 4′, 6-diamidino-2-phenylindole
- ELISA, enzyme-linked immunosorbent assay
- FCS, fetal calf serum
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- HCQ, hydroxychloroquine
- HSPA8/HSC70
- LAMP2A, lysosomal-associated membrane protein 2A
- LC-MS, liquid chromatography-mass spectrometry
- LC3-II, MAP1LC3-II
- MHCII, major histocompatibility complex class II
- NBD, nucleotide binding domain
- PBS, phosphate-buffered saline
- RP-HPLC, reversed-phase high-performance liquid chromatography
- RPL5, ribosomal protein L5
- SBD, substrate binding domain
- SD, standard deviation
- SEM, standard error of the mean
- SLE, systemic lupus erythematosus
- SNRNP70/U170K: small nuclear ribonucleoprotein 70kDa
- SQSTM1/p62, sequestosome 1
- TF, transferrin
- TFA, trifluoroacetic acid
- antigen-presenting cells
- autophagy
- bodipy: BODIPY FL C5 Lactosylceramide/bovine serum albumin
- chaperone-mediated autophagy
- class II MHC molecules
- heat shock proteins
- iv, intravenous
- lupus
- lysosomal chaperones
- lysosomes
- paraquat, 1, 1′-dimethyl-4, 4′-bipyridyldinium dichloride
- qRT-PCR, quantitative reverse transcriptase-polymerase chain reaction
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Affiliation(s)
- Christophe Macri
- a CNRS; Immunopathologie et chimie thérapeutique/Laboratory of excellence Medalis ; Institut de Biologie Moléculaire et Cellulaire ; Strasbourg , France
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Namkoong S, Lee KI, Lee JI, Park R, Lee EJ, Jang IS, Park J. The integral membrane protein ITM2A, a transcriptional target of PKA-CREB, regulates autophagic flux via interaction with the vacuolar ATPase. Autophagy 2016; 11:756-68. [PMID: 25951193 PMCID: PMC4509440 DOI: 10.1080/15548627.2015.1034412] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The PKA-CREB signaling pathway is involved in many cellular processes including autophagy. Recent studies demonstrated that PKA-CREB inhibits autophagy in yeast; however, the role of PKA-CREB signaling in mammalian cell autophagy has not been fully characterized. Here, we report that the integral membrane protein ITM2A expression is positively regulated by PKA-CREB signaling and ITM2A expression interferes with autophagic flux by interacting with vacuolar ATPase (v-ATPase). The ITM2A promoter contains a CRE element, and mutation at the CRE consensus site decreases the promoter activity. Forskolin treatment and PKA expression activate the ITM2A promoter confirming that ITM2A expression is dependent on the PKA-CREB pathway. ITM2A expression results in the accumulation of autophagosomes and interferes with autolysosome formation by blocking autophagic flux. We demonstrated that ITM2A physically interacts with v-ATPase and inhibits lysosomal function. These results support the notion that PKA-CREB signaling pathway regulates ITM2A expression, which negatively regulates autophagic flux by interfering with the function of v-ATPase.
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Key Words
- BafA1, bafilomycin A1
- CRE, cAMP response element
- CREB
- CREB, cAMP responsive element binding protein
- ChIP, chromatin immunoprecipitation
- EBSS, Earle's balanced salt solution
- ITM2A
- ITM2A, integral membrane protein 2A
- LAMP1, lysosomal-associated membrane protein 1
- MAP1LC3B/LC3B, microtubule-associated protein 1 light chain 3 β
- MAPK, mitogen-activated protein kinase
- MTOR, mechanistic target of rapamycin
- PKA
- PKA, protein kinase A
- SQSTM1, sequestosome 1
- TPA, 12-O-tetradecanoylphorbol-13-acetate
- autophagy
- cAMP, cyclic adenosine monophosphate
- tfLC3, tandem fluorescent-tagged LC3
- v-ATPase
- v-ATPase, vacuolar ATPase.
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Affiliation(s)
- Sim Namkoong
- a Division of Biological Science and Technology; Yonsei University ; Wonju , Korea
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55
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Xu X, Yuan X, Li N, Dewey WL, Li PL, Zhang F. Lysosomal cholesterol accumulation in macrophages leading to coronary atherosclerosis in CD38(-/-) mice. J Cell Mol Med 2016; 20:1001-13. [PMID: 26818887 PMCID: PMC4882979 DOI: 10.1111/jcmm.12788] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 12/13/2015] [Indexed: 12/16/2022] Open
Abstract
The disruption in transportation of oxLDL‐derived cholesterol and the subsequent lipid accumulation in macrophages are the hallmark events in atherogenesis. Our recent studies demonstrated that lysosomal Ca2+ messenger of nicotinic acid adenine dinucleotide phosphate (NAADP), an enzymatic product of CD38 ADP‐ribosylcyclase (CD38), promoted lipid endocytic trafficking in human fibroblast cells. The current studies are designed to examine the functional role of CD38/NAADP pathway in the regulation of lysosomal cholesterol efflux in atherosclerosis. Oil red O staining showed that oxLDL concentration‐dependently increased lipid buildup in bone marrow‐derived macrophages from both wild type and CD38−/−, but to a significant higher extent with CD38 gene deletion. Bodipy 493/503 fluorescence staining found that the deposited lipid in macrophages was mainly enclosed in lysosomal organelles and largely enhanced with the blockade of CD38/NAADP pathway. Filipin staining and direct measurement of lysosome fraction further revealed that the free cholesterol constituted a major portion of the total cholesterol segregated in lysosomes. Moreover, in situ assay disclosed that both lysosomal lumen acidity and the acid lipase activity were reduced upon cholesterol buildup in lysosomes. In CD38−/− mice, treatment with Western diet (12 weeks) produced atherosclerotic damage in coronary artery with striking lysosomal cholesterol sequestration in macrophages. These data provide the first experimental evidence that the proper function of CD38/NAADP pathway plays an essential role in promoting free cholesterol efflux from lysosomes and that a defection of this signalling leads to lysosomal cholesterol accumulation in macrophages and results in coronary atherosclerosis in CD38−/− mice.
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Affiliation(s)
- Xiaoyang Xu
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Xinxu Yuan
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Ningjun Li
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - William L Dewey
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Pin-Lan Li
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Fan Zhang
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
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56
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Parambath M, Hanley QS, Martin-Martinez FJ, Giesa T, Buehler MJ, Perry CC. The nature of the silicaphilic fluorescence of PDMPO. Phys Chem Chem Phys 2016; 18:5938-48. [DOI: 10.1039/c5cp05105c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Interactions with silica moderates the fluorescence behaviour of PDMPO.
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Affiliation(s)
- Mithun Parambath
- School of Science and Technology
- Nottingham Trent University
- Nottingham
- UK
| | - Quentin S. Hanley
- School of Science and Technology
- Nottingham Trent University
- Nottingham
- UK
| | | | - Tristan Giesa
- Department of Civil and Environmental Engineering
- Massachusetts Institute of Technology
- USA
| | - Markus J. Buehler
- Department of Civil and Environmental Engineering
- Massachusetts Institute of Technology
- USA
| | - Carole C. Perry
- School of Science and Technology
- Nottingham Trent University
- Nottingham
- UK
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57
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Wang C, Wang Y, Li Y, Bodemann B, Zhao T, Ma X, Huang G, Hu Z, DeBerardinis RJ, White MA, Gao J. A nanobuffer reporter library for fine-scale imaging and perturbation of endocytic organelles. Nat Commun 2015; 6:8524. [PMID: 26437053 PMCID: PMC4600749 DOI: 10.1038/ncomms9524] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 09/01/2015] [Indexed: 02/07/2023] Open
Abstract
Endosomes, lysosomes and related catabolic organelles are a dynamic continuum of vacuolar structures that impact a number of cell physiological processes such as protein/lipid metabolism, nutrient sensing and cell survival. Here we develop a library of ultra-pH-sensitive fluorescent nanoparticles with chemical properties that allow fine-scale, multiplexed, spatio-temporal perturbation and quantification of catabolic organelle maturation at single organelle resolution to support quantitative investigation of these processes in living cells. Deployment in cells allows quantification of the proton accumulation rate in endosomes; illumination of previously unrecognized regulatory mechanisms coupling pH transitions to endosomal coat protein exchange; discovery of distinct pH thresholds required for mTORC1 activation by free amino acids versus proteins; broad-scale characterization of the consequence of endosomal pH transitions on cellular metabolomic profiles; and functionalization of a context-specific metabolic vulnerability in lung cancer cells. Together, these biological applications indicate the robustness and adaptability of this nanotechnology-enabled 'detection and perturbation' strategy.
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Affiliation(s)
- Chensu Wang
- Department of Pharmacology, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Yiguang Wang
- Department of Pharmacology, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Yang Li
- Department of Pharmacology, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Brian Bodemann
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Tian Zhao
- Department of Pharmacology, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Xinpeng Ma
- Department of Pharmacology, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Gang Huang
- Department of Pharmacology, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Zeping Hu
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Ralph J. DeBerardinis
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Michael A. White
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Jinming Gao
- Department of Pharmacology, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
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58
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McNair HM, Brzezinski MA, Krause JW. Quantifying diatom silicification with the fluorescent dye, PDMPO. LIMNOLOGY AND OCEANOGRAPHY, METHODS 2015; 13:587-599. [PMID: 26793033 PMCID: PMC4715898 DOI: 10.1002/lom3.10049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Diatoms require silicic acid to construct ornately detailed cell walls called frustules. The growth and geographic distribution of diatoms is often controlled by the availability of silicic acid. Analytical methods exist to assess diatom community biogenic silica (bSiO2) production, but partitioning production among taxa has been largely qualitative. We present a method for the quantitative analysis of taxa-specific silica production through labeling diatoms with the fluorescent dye PDMPO [2-(4-pyridyl)-5-((4-(2-dimethylaminoethylaminocarbamoyl)methoxy)phenyl)oxazole]. To make PDMPO a quantitative tool: diatom frustules were solubilized to assess the total diatom community incorporation by quantitation of PDMPO fluorescence using a fluorometer, and laser confocal microscopy was used to quantify the fluorescence of PDMPO in single diatom cells. We created a fluorescence standard to intercalibrate the raw fluorescence signals of the fluorometer and microscope and to determine the fluorescence per mole of PDMPO. PDMPO incorporation was converted to silica production using diatom bSiO2:PDMPO incorporation ratios which varied systematically with silicic acid concentration. Above 3 μM Si(OH)4, bSiO2:PDMPO was constant and PDMPO incorporation was converted to silica production using a mole ratio of 2,916 as determined from cultures. Below 3 μM, the ratio was a linear function of [Si(OH)4] (bSiO2:PDMPO = 912.6 × [Si(OH)4]), as determined using data from two oceanographic cruises. Field evaluation of the method showed that total community PDMPO incorporation generally agreed to within 30% of radioisotope-determined silica production. This PDMPO method has the potential to be a powerful tool for understanding physiology, silicification and resource competition among diatom taxa.
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Affiliation(s)
- Heather M. McNair
- Department of Ecology Evolution and Marine Biology, University of
California, Santa Barbara, California 93106, United States of America
| | - Mark A. Brzezinski
- Department of Ecology Evolution and Marine Biology, University of
California, Santa Barbara, California 93106, United States of America
- Marine Science Institute, University of California, Santa Barbara,
California 93106, United States of America
| | - Jeffrey W. Krause
- Marine Science Institute, University of California, Santa Barbara,
California 93106, United States of America
- Dauphin Island Sea Lab, Dauphin Island, Alabama 36528, United States
of America
- Department of Marine Sciences, University of South Alabama, Mobile,
Alabama 36688, United States of America
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59
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Akita H, Noguchi Y, Hatakeyama H, Sato Y, Tange K, Nakai Y, Harashima H. Molecular Tuning of a Vitamin E-Scaffold pH-Sensitive and Reductive Cleavable Lipid-like Material for Accelerated in Vivo Hepatic siRNA Delivery. ACS Biomater Sci Eng 2015; 1:834-844. [DOI: 10.1021/acsbiomaterials.5b00203] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hidetaka Akita
- Laboratory
for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Science, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, Japan
| | - Yuki Noguchi
- Laboratory
for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Science, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, Japan
| | - Hiroto Hatakeyama
- Laboratory
for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Science, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, Japan
| | - Yusuke Sato
- Laboratory
for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Science, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, Japan
| | - Kota Tange
- NOF Corporation, 3-3 Chidori-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-0865, Japan
| | - Yuta Nakai
- NOF Corporation, 3-3 Chidori-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-0865, Japan
| | - Hideyoshi Harashima
- Laboratory
for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Science, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, Japan
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60
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Søndergaard RV, Christensen NM, Henriksen JR, Kumar EKP, Almdal K, Andresen TL. Facing the Design Challenges of Particle-Based Nanosensors for Metabolite Quantification in Living Cells. Chem Rev 2015; 115:8344-78. [PMID: 26244372 DOI: 10.1021/cr400636x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Rikke V Søndergaard
- Department of Micro- and Nanotechnology, Technical University of Denmark , Produktionstorvet 423, 2800 Lyngby, Denmark
| | - Nynne M Christensen
- Department of Micro- and Nanotechnology, Technical University of Denmark , Produktionstorvet 423, 2800 Lyngby, Denmark
| | - Jonas R Henriksen
- Department of Micro- and Nanotechnology, Technical University of Denmark , Produktionstorvet 423, 2800 Lyngby, Denmark
| | - E K Pramod Kumar
- Department of Micro- and Nanotechnology, Technical University of Denmark , Produktionstorvet 423, 2800 Lyngby, Denmark
| | - Kristoffer Almdal
- Department of Micro- and Nanotechnology, Technical University of Denmark , Produktionstorvet 423, 2800 Lyngby, Denmark
| | - Thomas L Andresen
- Department of Micro- and Nanotechnology, Technical University of Denmark , Produktionstorvet 423, 2800 Lyngby, Denmark
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61
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Leucine-Rich Repeat Kinase 1 Regulates Autophagy through Turning On TBC1D2-Dependent Rab7 Inactivation. Mol Cell Biol 2015; 35:3044-58. [PMID: 26100023 DOI: 10.1128/mcb.00085-15] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 06/19/2015] [Indexed: 01/23/2023] Open
Abstract
Autophagy is a conserved process that enables catabolic and degradative pathways. Rab family proteins, which are active in the GTP-bound form, regulate the transport and fusion of autophagosomes. However, it remains unclear how each cycle of Rab activation and inactivation is precisely regulated. Here, we show that leucine-rich repeat kinase 1 (LRRK1) regulates autophagic flux by controlling Rab7 activity in autolysosome formation. Upon induction of autophagy, LRRK1 was recruited via an association with VAMP7 to the autolysosome, where it activated the Rab7 GTPase-activating protein (GAP) TBC1D2, thereby switching off Rab7 signaling. Consistent with this model, LRRK1 deletion caused mice to be vulnerable to starvation and disrupted autolysosome formation, as evidenced by the accumulation of enlarged autolysosomes with undegraded LC3-II and persistently high levels of Rab7-GTP. This defect in autophagic flux was partially rescued by a mutant form of TBC1D2 with elevated Rab7-GAP activity. Thus, the spatiotemporal regulation of Rab7 activity during tunicamycin-induced autophagy is regulated by LRRK1.
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62
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Effect of solvents and cyclodextrin complexation on acid–base and photophysical properties of dapoxyl dye. J Photochem Photobiol A Chem 2015. [DOI: 10.1016/j.jphotochem.2015.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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63
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Wang F, Muller S. Manipulating autophagic processes in autoimmune diseases: a special focus on modulating chaperone-mediated autophagy, an emerging therapeutic target. Front Immunol 2015; 6:252. [PMID: 26042127 PMCID: PMC4437184 DOI: 10.3389/fimmu.2015.00252] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/07/2015] [Indexed: 12/14/2022] Open
Abstract
Autophagy, a constitutive intracellular degradation pathway, displays essential role in the homeostasis of immune cells, antigen processing and presentation, and many other immune processes. Perturbation of autophagy has been shown to be related to several autoimmune syndromes, including systemic lupus erythematosus. Therefore, modulating autophagy processes appears most promising for therapy of such autoimmune diseases. Autophagy can be said non-selective or selective; it is classified into three main forms, namely macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA), the former process being by far the most intensively investigated. The role of CMA remains largely underappreciated in autoimmune diseases, even though CMA has been claimed to play pivotal functions into major histocompatibility complex class II-mediated antigen processing and presentation. Therefore, hereby, we give a special focus on CMA as a therapeutic target in autoimmune diseases, based in particular on our most recent experimental results where a phosphopeptide modulates lupus disease by interacting with CMA regulators. We propose that specifically targeting lysosomes and lysosomal pathways, which are central in autophagy processes and seem to be altered in certain autoimmune diseases such as lupus, could be an innovative approach of efficient and personalized treatment.
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Affiliation(s)
- Fengjuan Wang
- Immunopathology and Therapeutic Chemistry/Laboratory of Excellence MEDALIS, CNRS, Institut de Biologie Moléculaire et Cellulaire , Strasbourg , France
| | - Sylviane Muller
- Immunopathology and Therapeutic Chemistry/Laboratory of Excellence MEDALIS, CNRS, Institut de Biologie Moléculaire et Cellulaire , Strasbourg , France ; University of Strasbourg Institute for Advanced Study , Strasbourg , France
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64
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Wexselblatt E, Esko JD, Tor Y. GNeosomes: Highly Lysosomotropic Nanoassemblies for Lysosomal Delivery. ACS NANO 2015; 9:3961-3968. [PMID: 25831231 DOI: 10.1021/nn507382n] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
GNeosomes, lysosomotropic lipid vesicles decorated with guanidinoneomycin, can encapsulate and facilitate the cellular internalization and lysosomal delivery of cargo ranging from small molecules to high molecular weight proteins, in a process that is exclusively dependent on cell surface glycosaminoglycans. Their cellular uptake mechanism and co-localization with lysosomes, as well as the delivery, release, and activity of internalized cargo, are quantified. GNeosomes are proposed as a universal platform for lysosomal delivery with potential as a basic research tool and a therapeutic vehicle.
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Affiliation(s)
- Ezequiel Wexselblatt
- †Chemistry and Biochemistry and ‡Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Jeffrey D Esko
- †Chemistry and Biochemistry and ‡Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Yitzhak Tor
- †Chemistry and Biochemistry and ‡Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
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65
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Zhang J, Yang M, Li C, Dorh N, Xie F, Luo FT, Tiwari A, Liu H. Near-infrared fluorescent probes based on piperazine-functionalized BODIPY dyes for sensitive detection of lysosomal pH. J Mater Chem B 2015; 3:2173-2184. [PMID: 32262385 DOI: 10.1039/c4tb01878h] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Three acidotropic, near-infrared fluorescent probes based on piperazine-modified BODIPY dyes (A, B and C) have been developed for the sensitive and selective detection of lysosomal pH in living cells. Probes A and B display low solubilities in aqueous solutions, whereas probe C is highly water-soluble. The fluorescent responsive mechanism of these probes to lysosomal pH is based on intramolecular charge transfer (ICT) and potential photo-induced electron transfer from piperazine moieties at 3,5-positions to BODIPY cores in the near-infrared region. The sensitivity and selectivity of the probes to pH over metal ions have been investigated by spectroscopic analysis in aqueous solutions. The probes have low auto-fluorescence at physiological pH conditions, whereas their fluorescence intensities significantly increase when pH is shifted to an acidic condition. Furthermore, these three probes were successfully applied to the in vitro lysosome imaging inside normal endothelial and breast cancer cells.
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Affiliation(s)
- Jingtuo Zhang
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA.
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66
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Liu J, Walker NM, Ootani A, Strubberg AM, Clarke LL. Defective goblet cell exocytosis contributes to murine cystic fibrosis-associated intestinal disease. J Clin Invest 2015; 125:1056-68. [PMID: 25642775 DOI: 10.1172/jci73193] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 12/18/2014] [Indexed: 01/12/2023] Open
Abstract
Cystic fibrosis (CF) intestinal disease is associated with the pathological manifestation mucoviscidosis, which is the secretion of tenacious, viscid mucus that plugs ducts and glands of epithelial-lined organs. Goblet cells are the principal cell type involved in exocytosis of mucin granules; however, little is known about the exocytotic process of goblet cells in the CF intestine. Using intestinal organoids from a CF mouse model, we determined that CF goblet cells have altered exocytotic dynamics, which involved intrathecal granule swelling that was abruptly followed by incomplete release of partially decondensated mucus. Some CF goblet cells exhibited an ectopic granule location and distorted cellular morphology, a phenotype that is consistent with retrograde intracellular granule movement during exocytosis. Increasing the luminal concentration of bicarbonate, which mimics CF transmembrane conductance regulator-mediated anion secretion, increased spontaneous degranulation in WT goblet cells and improved exocytotic dynamics in CF goblet cells; however, there was still an apparent incoordination between granule decondensation and exocytosis in the CF goblet cells. Compared with those within WT goblet cells, mucin granules within CF goblet cells had an alkaline pH, which may adversely affect the polyionic composition of the mucins. Together, these findings indicate that goblet cell dysfunction is an epithelial-autonomous defect in the CF intestine that likely contributes to the pathology of mucoviscidosis and the intestinal manifestations of obstruction and inflammation.
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Abstract
The technique of dual-wavelength ratio fluorescence microscopy provides a powerful tool to measure organellar pH. Unlike single-wavelength measurements, this method is unaffected by changes in focal plane, dye volume, and fluorophore bleaching, providing a quantitative and dynamic readout of the pH of subcellular compartments. This chapter describes the application of dual-wavelength ratio fluorescence microscopy to the measurement of lysosomal pH, highlighting its advantages and limitations. Probe selection, calibration methods, and salient aspects of the required hardware are discussed in detail.
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Affiliation(s)
- Johnathan Canton
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario, M5G 0A4
| | - Sergio Grinstein
- Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, M5C 1N8, Canada
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68
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Wan Q, Chen S, Shi W, Li L, Ma H. Lysosomal pH Rise during Heat Shock Monitored by a Lysosome-Targeting Near-Infrared Ratiometric Fluorescent Probe. Angew Chem Int Ed Engl 2014; 53:10916-20. [DOI: 10.1002/anie.201405742] [Citation(s) in RCA: 334] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 07/29/2014] [Indexed: 12/12/2022]
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69
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Wan Q, Chen S, Shi W, Li L, Ma H. Lysosomal pH Rise during Heat Shock Monitored by a Lysosome-Targeting Near-Infrared Ratiometric Fluorescent Probe. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201405742] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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70
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Cardona MA, Magri DC. Synthesis and spectrophotometric studies of water-soluble amino[bis(ethanesulfonate)] azobenzene pH indicators. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.06.079] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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71
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Zhang M, Zheng S, Ma L, Zhao M, Deng L, Yang L, Ma LJ. Dansyl-8-aminoquinoline as a sensitive pH fluorescent probe with dual-responsive ranges in aqueous solutions. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 124:682-686. [PMID: 24529362 DOI: 10.1016/j.saa.2013.12.062] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 11/26/2013] [Accepted: 12/08/2013] [Indexed: 06/03/2023]
Abstract
A sensitive pH fluorescent probe based on dansyl group, dansyl-8-aminoquinoline (DAQ), has been synthesized. The probe showed dual-responsive ranges to pH changes, one range from 2.00 to 7.95 and another one from 7.95 to 10.87 in aqueous solution, as it showed pKa values of 5.73 and 8.56 under acid and basic conditions, respectively. Furthermore, the pH response mechanism of the probe was explored successfully by using NMR spectra. The results indicated that the responses of DAQ to pH changes should attribute to the protonation of the nitrogen atom in the dimethylamino group and deprotonation of sulfonamide group.
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Affiliation(s)
- Min Zhang
- School of Chemistry and Environment, South China Normal University, Shipai, Guangzhou 510631, PR China
| | - Shuyu Zheng
- School of Chemistry and Environment, South China Normal University, Shipai, Guangzhou 510631, PR China
| | - Liguo Ma
- College of Chemical Engineering, China University of Petroleum, Beijing 102200, PR China.
| | - Meili Zhao
- School of Chemistry and Environment, South China Normal University, Shipai, Guangzhou 510631, PR China
| | - Lengfang Deng
- School of Chemistry and Environment, South China Normal University, Shipai, Guangzhou 510631, PR China
| | - Liting Yang
- School of Chemistry and Environment, South China Normal University, Shipai, Guangzhou 510631, PR China
| | - Li-Jun Ma
- School of Chemistry and Environment, South China Normal University, Shipai, Guangzhou 510631, PR China.
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72
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Vegesna GK, Janjanam J, Bi J, Luo FT, Zhang J, Olds C, Tiwari A, Liu H. pH-activatable near-infrared fluorescent probes for detection of lysosomal pH inside living cells. J Mater Chem B 2014; 2:4500-4508. [DOI: 10.1039/c4tb00475b] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Four near-infrared fluorescent probes have been synthesized, characterized, and evaluated for detection of lysosomal pH inside living cells.
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Affiliation(s)
- Giri K. Vegesna
- Department of Chemistry
- Michigan Technological University
- Houghton, USA
| | | | - Jianheng Bi
- Department of Chemistry
- Michigan Technological University
- Houghton, USA
| | - Fen-Tair Luo
- Institute of Chemistry
- Academia Sinica
- Taipei, Republic of China
| | - Jingtuo Zhang
- Department of Chemistry
- Michigan Technological University
- Houghton, USA
| | - Connor Olds
- Department of Chemistry
- Michigan Technological University
- Houghton, USA
| | - Ashutosh Tiwari
- Department of Chemistry
- Michigan Technological University
- Houghton, USA
| | - Haiying Liu
- Department of Chemistry
- Michigan Technological University
- Houghton, USA
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73
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Zhu L, Yuan Z, Simmons JT, Sreenath K. Zn(II)-coordination modulated ligand photophysical processes - the development of fluorescent indicators for imaging biological Zn(II) ions. RSC Adv 2014; 4:20398-20440. [PMID: 25071933 PMCID: PMC4111279 DOI: 10.1039/c4ra00354c] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Molecular photophysics and metal coordination chemistry are the two fundamental pillars that support the development of fluorescent cation indicators. In this article, we describe how Zn(II)-coordination alters various ligand-centered photophysical processes that are pertinent to developing Zn(II) indicators. The main aim is to show how small organic Zn(II) indicators work under the constraints of specific requirements, including Zn(II) detection range, photophysical requirements such as excitation energy and emission color, temporal and spatial resolutions in a heterogeneous intracellular environment, and fluorescence response selectivity between similar cations such as Zn(II) and Cd(II). In the last section, the biological questions that fluorescent Zn(II) indicators help to answer are described, which have been motivating and challenging this field of research.
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Affiliation(s)
- Lei Zhu
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390, United States
| | - Zhao Yuan
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390, United States
| | - J. Tyler Simmons
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390, United States
| | - Kesavapillai Sreenath
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390, United States
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74
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Yu KK, Li K, Hou JT, Qin HH, Xie YM, Qian CH, Yu XQ. Rhodamine-based lysosome-targeted fluorescence probes: high pH sensitivity and their imaging application in living cells. RSC Adv 2014. [DOI: 10.1039/c4ra05215c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Two rhodamine-based pH probes were synthesized via the click reaction. Cell imaging experiments demonstrated RhPA was a good lysosome targeting probe in living cells with low cytotoxicity and excellent photostability.
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Affiliation(s)
- Kang-Kang Yu
- Key Laboratory of Green Chemistry and Technology
- Ministry of Education
- College of Chemistry
- Sichuan University
- Chengdu, P. R. China
| | - Kun Li
- Key Laboratory of Green Chemistry and Technology
- Ministry of Education
- College of Chemistry
- Sichuan University
- Chengdu, P. R. China
| | - Ji-Ting Hou
- Key Laboratory of Green Chemistry and Technology
- Ministry of Education
- College of Chemistry
- Sichuan University
- Chengdu, P. R. China
| | - Hui-Huan Qin
- Key Laboratory of Green Chemistry and Technology
- Ministry of Education
- College of Chemistry
- Sichuan University
- Chengdu, P. R. China
| | - Yong-Mei Xie
- State Key Laboratory of Biotherapy
- West China Hospital
- West China Medical School
- Sichuan University
- Chengdu 610041, China
| | - Chen-Hui Qian
- Key Laboratory of Green Chemistry and Technology
- Ministry of Education
- College of Chemistry
- Sichuan University
- Chengdu, P. R. China
| | - Xiao-Qi Yu
- Key Laboratory of Green Chemistry and Technology
- Ministry of Education
- College of Chemistry
- Sichuan University
- Chengdu, P. R. China
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75
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Fluorescent imaging of acidic compartments in living cells with a high selective novel one-photon ratiometric and two-photon acidic pH probe. Biosens Bioelectron 2013; 50:42-9. [DOI: 10.1016/j.bios.2013.05.060] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 05/30/2013] [Accepted: 05/31/2013] [Indexed: 11/17/2022]
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76
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Kim HJ, Heo CH, Kim HM. Benzimidazole-Based Ratiometric Two-Photon Fluorescent Probes for Acidic pH in Live Cells and Tissues. J Am Chem Soc 2013; 135:17969-77. [DOI: 10.1021/ja409971k] [Citation(s) in RCA: 279] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Hyung Joong Kim
- Division of Energy Systems
Research, Ajou University, Suwon 443-749, Korea
| | - Cheol Ho Heo
- Division of Energy Systems
Research, Ajou University, Suwon 443-749, Korea
| | - Hwan Myung Kim
- Division of Energy Systems
Research, Ajou University, Suwon 443-749, Korea
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77
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A new near-infrared neutral pH fluorescent probe for monitoring minor pH changes and its application in imaging of HepG2 cells. Appl Biochem Biotechnol 2013; 172:1036-44. [PMID: 24142355 DOI: 10.1007/s12010-013-0573-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 09/30/2013] [Indexed: 10/26/2022]
Abstract
A new near-neutral pH near-infrared (NIR) fluorescent probe utilizing a fluorophore-receptor molecular framework that can modulate the fluorescence emission intensity through a fast photoinduced electron transfer process was developed. Our strategy was to choose tricarbocyanine (Cy), a NIR fluorescent dye with high extinction coefficients, as a fluorophore, and N-methylpiperazine (MP) as a receptor. The pH titration indicated that MP-Cy can monitor the minor physiological pH fluctuations with a pKa of ∼7.10 near physiological pH, which is valuable for intracellular pH researches. The probe responds linearly and rapidly to minor pH fluctuations within the range of 3.05-7.10 and exhibits strong dependence on pH changes. As expected, the real-time imaging of cellular pH and the detection of pH in situ was achieved successfully in living HepG2 cells by this probe. It is shown that the probe effectively avoids the influence of autofluorescence and native cellular species in biological systems and meanwhile exhibits high sensitivity, good photostability, and excellent cell membrane permeability.
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78
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King JS, Gueho A, Hagedorn M, Gopaldass N, Leuba F, Soldati T, Insall RH. WASH is required for lysosomal recycling and efficient autophagic and phagocytic digestion. Mol Biol Cell 2013; 24:2714-26. [PMID: 23885127 PMCID: PMC3756923 DOI: 10.1091/mbc.e13-02-0092] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 06/05/2013] [Accepted: 07/01/2013] [Indexed: 12/22/2022] Open
Abstract
Wiskott-Aldrich syndrome protein and SCAR homologue (WASH) is an important regulator of vesicle trafficking. By generating actin on the surface of intracellular vesicles, WASH is able to directly regulate endosomal sorting and maturation. We report that, in Dictyostelium, WASH is also required for the lysosomal digestion of both phagocytic and autophagic cargo. Consequently, Dictyostelium cells lacking WASH are unable to grow on many bacteria or to digest their own cytoplasm to survive starvation. WASH is required for efficient phagosomal proteolysis, and proteomic analysis demonstrates that this is due to reduced delivery of lysosomal hydrolases. Both protease and lipase delivery are disrupted, and lipid catabolism is also perturbed. Starvation-induced autophagy therefore leads to phospholipid accumulation within WASH-null lysosomes. This causes the formation of multilamellar bodies typical of many lysosomal storage diseases. Mechanistically, we show that, in cells lacking WASH, cathepsin D becomes trapped in a late endosomal compartment, unable to be recycled to nascent phagosomes and autophagosomes. WASH is therefore required for the maturation of lysosomes to a stage at which hydrolases can be retrieved and reused.
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Affiliation(s)
- Jason S. King
- Beatson Institute for Cancer Research, Bearsden, Glasgow G61 1BD, United Kingdom
| | - Aurélie Gueho
- Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Monica Hagedorn
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany
| | - Navin Gopaldass
- Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Florence Leuba
- Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Robert H. Insall
- Beatson Institute for Cancer Research, Bearsden, Glasgow G61 1BD, United Kingdom
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79
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A new rhodamine B-based lysosomal pH fluorescent indicator. Anal Chim Acta 2013; 788:177-82. [DOI: 10.1016/j.aca.2013.06.038] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 06/18/2013] [Accepted: 06/24/2013] [Indexed: 11/22/2022]
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80
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Roy C, Gagné V, Fernandes MJ, Marceau F. High affinity capture and concentration of quinacrine in polymorphonuclear neutrophils via vacuolar ATPase-mediated ion trapping: Comparison with other peripheral blood leukocytes and implications for the distribution of cationic drugs. Toxicol Appl Pharmacol 2013; 270:77-86. [DOI: 10.1016/j.taap.2013.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 04/04/2013] [Accepted: 04/07/2013] [Indexed: 11/30/2022]
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81
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Gene recombinant bone marrow mesenchymal stem cells as a tumor-targeted suicide gene delivery vehicle in pulmonary metastasis therapy using non-viral transfection. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2013; 10:257-67. [PMID: 23770065 DOI: 10.1016/j.nano.2013.06.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 05/21/2013] [Accepted: 06/06/2013] [Indexed: 12/13/2022]
Abstract
UNLABELLED One of the main limitations of anti-tumor gene therapy is the lack of an effective way to deliver therapeutic genes to tumor sites. Bone marrow mesenchymal stem cells (BMSCs) have been proposed as cellular delivery vehicles to tumor sites in tumor-targeted cancer gene therapy. Here, we investigated the therapeutic effects of cytomegalovirus-thymidine kinase expressing BMSCs (TK-BMSCs) on pulmonary melanoma metastasis combined with prodrug ganciclovir. BMSCs were successfully engineered through a non-viral gene vector. The gene recombinant BMSCs migrated to the pulmonary area and were found to have the tendency to target tumor nodules after systemic delivery. In vitro results demonstrate that the engineered BMSCs have significant suicide effects in the presence of ganciclovir in a dose-dependent manner and can exert a sufficient bystander effect on B16F10 tumor cells in co-culture experiments. In vivo studies confirmed the therapeutic effects of TK-BMSCs/ganciclovir on the metastasis tumor model. FROM THE CLINICAL EDITOR This study investigates the possibility of gene transfer via bone marrow mesenchymal stem cells in anti-cancer gene therapy using a metastatic melanoma model and cytomegalovirus-thymidine kinase expressing stem cells, demonstrating clear therapeutic effects.
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82
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Mahuteau-Betzer F, Piguel S. Synthesis and evaluation of photophysical properties of Series of π-conjugated oxazole dyes. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.04.037] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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83
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Wolfe DM, Lee JH, Kumar A, Lee S, Orenstein SJ, Nixon RA. Autophagy failure in Alzheimer's disease and the role of defective lysosomal acidification. Eur J Neurosci 2013; 37:1949-61. [PMID: 23773064 PMCID: PMC3694736 DOI: 10.1111/ejn.12169] [Citation(s) in RCA: 256] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 01/22/2013] [Accepted: 01/28/2013] [Indexed: 12/12/2022]
Abstract
Autophagy is a lysosomal degradative process which recycles cellular waste and eliminates potentially toxic damaged organelles and protein aggregates. The important cytoprotective functions of autophagy are demonstrated by the diverse pathogenic consequences that may stem from autophagy dysregulation in a growing number of neurodegenerative disorders. In many of the diseases associated with autophagy anomalies, it is the final stage of autophagy-lysosomal degradation that is disrupted. In several disorders, including Alzheimer's disease (AD), defective lysosomal acidification contributes to this proteolytic failure. The complex regulation of lysosomal pH makes this process vulnerable to disruption by many factors, and reliable lysosomal pH measurements have become increasingly important in investigations of disease mechanisms. Although various reagents for pH quantification have been developed over several decades, they are not all equally well suited for measuring the pH of lysosomes. Here, we evaluate the most commonly used pH probes for sensitivity and localisation, and identify LysoSensor yellow/blue-dextran, among currently used probes, as having the optimal profile of properties for measuring lysosomal pH. In addition, we review evidence that lysosomal acidification is defective in AD and extend our original findings, of elevated lysosomal pH in presenilin 1 (PS1)-deficient blastocysts and neurons, to additional cell models of PS1 and PS1/2 deficiency, to fibroblasts from AD patients with PS1 mutations, and to neurons in the PS/APP mouse model of AD.
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Affiliation(s)
- Devin M. Wolfe
- Center for Dementia Research, Nathan S. Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY, USA, 10962
| | - Ju-hyun Lee
- Center for Dementia Research, Nathan S. Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY, USA, 10962
- Department of Psychiatry, New York University, 550 First Ave, New York, NY, USA 10016
| | - Asok Kumar
- Center for Dementia Research, Nathan S. Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY, USA, 10962
- Department of Pathology, New York University, 550 First Ave, New York, NY, USA 10016
| | - Sooyeon Lee
- Center for Dementia Research, Nathan S. Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY, USA, 10962
| | - Samantha J. Orenstein
- Department of Developmental and Molecular Biology, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY, USA 10461
| | - Ralph A. Nixon
- Center for Dementia Research, Nathan S. Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY, USA, 10962
- Department of Psychiatry, New York University, 550 First Ave, New York, NY, USA 10016
- Department of Cell Biology, New York University, 550 First Ave, New York, NY, USA 10016
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84
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Sillence DJ. Glucosylceramide modulates endolysosomal pH in Gaucher disease. Mol Genet Metab 2013; 109:194-200. [PMID: 23628459 DOI: 10.1016/j.ymgme.2013.03.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 03/25/2013] [Accepted: 03/25/2013] [Indexed: 10/27/2022]
Abstract
GlcCer accumulation causes Gaucher disease where GlcCer breakdown is inhibited due to a hereditary deficiency in glucocerebrosidase. Glycolipids are endocytosed and targeted to the Golgi apparatus in normal cells but in Gaucher disease they are mistargeted to lysosomes. To better understand the role of GlcCer in endocytic sorting RAW macrophages were treated with Conduritol B-epoxide to inhibit GlcCer breakdown. Lipid analysis found increases in GlcCer led to accumulation of both triacylglycerol and cholesterol consistent with increased lysosomal pH. Ratio imaging of macrophages using both acridine orange and lysosensor yellow/blue to measure endolysosomal pH revealed increases in Conduritol B-epoxide treated RAW macrophages and Gaucher patient lymphoblasts. Increased endolysosomal pH was restricted to Gaucher lymphoblasts as no significant increases in pH were seen in Fabry, Krabbe, Tay-Sachs and GM1-gangliosidosis lymphoblasts. Substrate reduction therapy utilises inhibitors of GlcCer synthase to reduce storage in Gaucher disease. The addition of inhibitors of GlcCer synthesis to RAW macrophages also led to increases in cholesterol and triacylglycerol and an endolysosomal pH increase of up to 1 pH unit. GlcCer modulation appears specific since glucosylsphingosine but not galactosylsphingosine reversed the effects of GlcCer depletion. Although no acute effects on glycolipid trafficking were observed using bafilomycin A the results are consistent with a multistep model whereby increases in pH lead to altered trafficking via cholesterol accumulation. GlcCer modulates endolysosomal pH in lymphocytes suggesting an important role in normal lysosomes which may be disrupted in Gaucher disease.
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Affiliation(s)
- Dan J Sillence
- Cell Signalling Lab. Leicester School of Pharmacy, De Montfort University, The Gateway, Leicester, LE1 9BH, UK.
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85
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Schneider R, Gohla A, Simard JR, Yadav DB, Fang Z, van Otterlo WAL, Rauh D. Overcoming compound fluorescence in the FLiK screening assay with red-shifted fluorophores. J Am Chem Soc 2013; 135:8400-8. [PMID: 23672540 DOI: 10.1021/ja403074j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In the attempt to discover novel chemical scaffolds that can modulate the activity of disease-associated enzymes, such as kinases, biochemical assays are usually deployed in high-throughput screenings. First-line assays, such as activity-based assays, often rely on fluorescent molecules by measuring a change in the total emission intensity, polarization state, or energy transfer to another fluorescent molecule. However, under certain conditions, intrinsic compound fluorescence can lead to difficult data analysis and to false-positive, as well as false-negative, hits. We have reported previously on a powerful direct binding assay called fluorescent labels in kinases ('FLiK'), which enables a sensitive measurement of conformational changes in kinases upon ligand binding. In this assay system, changes in the emission spectrum of the fluorophore acrylodan, induced by the binding of a ligand, are translated into a robust assay readout. However, under the excitation conditions of acrylodan, intrinsic compound fluorescence derived from highly conjugated compounds complicates data analysis. We therefore optimized this method by identifying novel fluorophores that excite in the far red, thereby avoiding compound fluorescence. With this advancement, even rigid compounds with multiple π-conjugated ring systems can now be measured reliably. This study was performed on three different kinase constructs with three different labeling sites, each undergoing distinct conformational changes upon ligand binding. It may therefore serve as a guideline for the establishment of novel fluorescence-based detection assays.
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Affiliation(s)
- Ralf Schneider
- Chemical Genomics Centre of the Max-Planck-Society , Otto-Hahn-Strasse 15, 44137 Dortmund, Germany
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86
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Key role for the alternative sigma factor, SigH, in the intracellular life of Mycobacterium avium subsp. paratuberculosis during macrophage stress. Infect Immun 2013; 81:2242-57. [PMID: 23569115 DOI: 10.1128/iai.01273-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium avium subsp. paratuberculosis causes Johne's disease, an enteric infection in cattle and other ruminants, greatly afflicting the dairy industry worldwide. Once inside the cell, M. avium subsp. paratuberculosis is known to survive harsh microenvironments, especially those inside activated macrophages. To improve our understanding of M. avium subsp. paratuberculosis pathogenesis, we examined phagosome maturation associated with transcriptional responses of M. avium subsp. paratuberculosis during macrophage infection. Monitoring cellular markers, only live M. avium subsp. paratuberculosis bacilli were able to prevent phagosome maturation and reduce its acidification. On the transcriptional level, over 300 M. avium subsp. paratuberculosis genes were significantly and differentially regulated in both naive and IFN-γ-activated macrophages. These genes include the sigma factor H (sigH) that was shown to be important for M. avium subsp. paratuberculosis survival inside gamma interferon (IFN-γ)-activated bovine macrophages. Interestingly, an sigH-knockout mutant showed increased sensitivity to a sustained level of thiol-specific oxidative stress. Large-scale RNA sequence analysis revealed that a large number of genes belong to the sigH regulon, especially following diamide stress. Genes involved in oxidative stress and virulence were among the induced genes in the sigH regulon with a putative consensus sequence for SigH binding that was recognized in a subset of these genes (n = 30), suggesting direct regulation by SigH. Finally, mice infections showed a significant attenuation of the ΔsigH mutant compared to its parental strain, suggesting a role for sigH in M. avium subsp. paratuberculosis virulence. Such analysis could identify potential targets for further testing as vaccine candidates against Johne's disease.
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87
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Marín MJ, Galindo F, Thomas P, Wileman T, Russell DA. A photoinduced electron transfer-based nanoprobe as a marker of acidic organelles in mammalian cells. Anal Bioanal Chem 2013; 405:6197-207. [DOI: 10.1007/s00216-013-6905-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 03/06/2013] [Accepted: 03/08/2013] [Indexed: 01/08/2023]
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88
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iRGD-coupled responsive fluorescent nanogel for targeted drug delivery. Biomaterials 2013; 34:3523-33. [DOI: 10.1016/j.biomaterials.2013.01.083] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 01/24/2013] [Indexed: 12/31/2022]
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89
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Long L, Li X, Zhang D, Meng S, Zhang J, Sun X, Zhang C, Zhou L, Wang L. Amino-coumarin based fluorescence ratiometric sensors for acidic pH and their application for living cells imaging. RSC Adv 2013. [DOI: 10.1039/c3ra41329b] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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90
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Men G, Zhang G, Liang C, Liu H, Yang B, Pan Y, Wang Z, Jiang S. A dual channel optical detector for trace water chemodosimetry and imaging of live cells. Analyst 2013; 138:2847-57. [DOI: 10.1039/c3an36887d] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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91
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Kudo K, Momotake A, Tanaka JK, Miwa Y, Arai T. Environmental polarity estimation in living cells by use of quinoxaline-based full-colored solvatochromic fluorophore PQX and its derivatives. Photochem Photobiol Sci 2012; 11:674-8. [DOI: 10.1039/c2pp05337c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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92
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Aabo T, Glückstad J, Siegumfeldt H, Arneborg N. Intracellular pH distribution as a cell health indicator in Saccharomyces cerevisiae. J R Soc Interface 2011; 8:1635-43. [PMID: 21527496 PMCID: PMC3177618 DOI: 10.1098/rsif.2011.0148] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 04/08/2011] [Indexed: 11/12/2022] Open
Abstract
Internal pH regulation is vital for many cell functions, including transport mechanisms and metabolic enzyme activity. More specifically, transport mechanisms are to a wide degree governed by internal pH distributions. We introduce the term standard deviation of the intracellular pH (s.d.(pH(int))) to describe the internal pH distributions. The cellular pH distributional response to external stress such as heat has not previously been determined. In this study, the intracellular pH (pH(i)) and the s.d.(pH(int)) of Saccharomyces cerevisiae cells exposed to supralethal temperatures were measured using fluorescence ratio imaging microscopy (FRIM). An exponential decline in pH(i) was observed after an initial small decline. For the first time, we report the use of FRIM for determining in vivo plasma membrane proton permeability coefficients in yeast. Furthermore, the exponential decay of pH(i) and the rupture of the cell plasma membrane, as measured by propidium iodide staining, at 70°C were not simultaneous but were separated by a significant temporal difference. Finally, a nonlinear relationship between the pH(i) and s.d.(pH(int)) was found; i.e. the s.d.(pH(int)) was significantly more sensitive to supralethal temperatures than pH(i). s.d.(pH(int)) is therefore proposed as an early health/vitality indicator in S. cerevisiae cells exposed to heat stress.
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Affiliation(s)
- Thomas Aabo
- Department of Food Science, University of Copenhagen, , Frederiksberg, Denmark.
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93
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Law C, Exley C. New insight into silica deposition in horsetail (Equisetum arvense). BMC PLANT BIOLOGY 2011; 11:112. [PMID: 21801378 PMCID: PMC3160890 DOI: 10.1186/1471-2229-11-112] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 07/29/2011] [Indexed: 05/04/2023]
Abstract
BACKGROUND The horsetails (Equisetum sp) are known biosilicifiers though the mechanism underlying silica deposition in these plants remains largely unknown. Tissue extracts from horsetails grown hydroponically and also collected from the wild were acid-digested in a microwave oven and their silica 'skeletons' visualised using the fluor, PDMPO, and fluorescence microscopy. RESULTS Silica deposits were observed in all plant regions from the rhizome through to the stem, leaf and spores. Numerous structures were silicified including cell walls, cell plates, plasmodesmata, and guard cells and stomata at varying stages of differentiation. All of the major sites of silica deposition in horsetail mimicked sites and structures where the hemicellulose, callose is known to be found and these serendipitous observations of the coincidence of silica and callose raised the possibility that callose might be templating silica deposition in horsetail. Hydroponic culture of horsetail in the absence of silicic acid resulted in normal healthy plants which, following acid digestion, showed no deposition of silica anywhere in their tissues. To test the hypothesis that callose might be templating silica deposition in horsetail commercially available callose was mixed with undersaturated and saturated solutions of silicic acid and the formation of silica was demonstrated by fluorimetry and fluorescence microscopy. CONCLUSIONS The initiation of silica formation by callose is the first example whereby any biomolecule has been shown to induce, as compared to catalyse, the formation of silica in an undersaturated solution of silicic acid. This novel discovery allowed us to speculate that callose and its associated biochemical machinery could be a missing link in our understanding of biosilicification.
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Affiliation(s)
- Chinnoi Law
- The Birchall Centre, Lennard-Jones Laboratories, Keele University, Staffordshire, ST5 5BG, UK
| | - Christopher Exley
- The Birchall Centre, Lennard-Jones Laboratories, Keele University, Staffordshire, ST5 5BG, UK
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94
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Liu X, Lu L, Yang Z, Palaniyandi S, Zeng R, Gao LY, Mosser DM, Roopenian DC, Zhu X. The neonatal FcR-mediated presentation of immune-complexed antigen is associated with endosomal and phagosomal pH and antigen stability in macrophages and dendritic cells. THE JOURNAL OF IMMUNOLOGY 2011; 186:4674-86. [PMID: 21402891 DOI: 10.4049/jimmunol.1003584] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The FcγRs found on macrophages (Ms) and dendritic cells (DCs) efficiently facilitate the presentation or cross-presentation of immune-complexed Ags to T cells. We found that the MHC class I-related neonatal FcR for IgG (FcRn) in both Ms and DCs failed to have a strong effect on the cross-presentation of immune complex (IC) OVA Ag to CD8(+) T cells. Interestingly, endosomal FcRn enhanced the presentation of the monomeric OVA-IC to CD4(+) T cells robustly, whereas FcRn in phagosomes exerted distinctive effects on Ag presentation between Ms and DCs. The presentation of phagocytosed OVA-ICs to CD4(+) T cells was considerably enhanced on wild-type versus FcRn-deficient Ms, but was not affected in FcRn-deficient DCs. This functional discrepancy was associated with the dependence of IgG-FcRn binding in an acidic pH. Following phagocytosis, the phagosomal pH dropped rapidly to <6.5 in Ms but remained in the neutral range in DCs. This disparity in pH determined the rate of degradation of phagocytosed ICs. Thus, our findings reveal that FcRn expression has a different effect on Ag processing and presentation of ICs to CD4(+) T cells in the endosomal versus phagosomal compartments of Ms versus DCs.
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Affiliation(s)
- Xindong Liu
- Laboratory of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA
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95
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Verrier C, Fiol-Petit C, Hoarau C, Marsais F. DPO and POPOP carboxylate-analog sensors by sequential palladium-catalysed direct arylation of oxazole-4-carboxylates. Org Biomol Chem 2011; 9:6215-8. [DOI: 10.1039/c1ob05261f] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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96
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Yang W, Lopez PJ, Rosengarten G. Diatoms: Self assembled silicananostructures, and templates for bio/chemical sensors and biomimetic membranes. Analyst 2011; 136:42-53. [DOI: 10.1039/c0an00602e] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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97
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Miao Q, Xu D, Wang Z, Xu L, Wang T, Wu Y, Lovejoy DB, Kalinowski DS, Richardson DR, Nie G, Zhao Y. Amphiphilic hyper-branched co-polymer nanoparticles for the controlled delivery of anti-tumor agents. Biomaterials 2010; 31:7364-75. [DOI: 10.1016/j.biomaterials.2010.06.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 06/01/2010] [Indexed: 11/15/2022]
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98
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Affiliation(s)
- Junyan Han
- Department of Chemistry, Texas A&M University, Box 30012, College Station, Texas 77841, USA
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99
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McCurley N, Mellman I. Monocyte-derived dendritic cells exhibit increased levels of lysosomal proteolysis as compared to other human dendritic cell populations. PLoS One 2010; 5:e11949. [PMID: 20689855 PMCID: PMC2914042 DOI: 10.1371/journal.pone.0011949] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Accepted: 07/10/2010] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Fine control of lysosomal degradation for limited processing of internalized antigens is a hallmark of professional antigen presenting cells. Previous work in mice has shown that dendritic cells (DCs) contain lysosomes with remarkably low protease content. Combined with the ability to modulate lysosomal pH during phagocytosis and maturation, murine DCs enhance their production of class II MHC-peptide complexes for presentation to T cells. METHODOLOGY/PRINCIPAL FINDINGS In this study we extend these findings to human DCs and distinguish between different subsets of DCs based on their ability to preserve internalized antigen. Whereas DCs derived in vitro from CD34+ hematopoietic progenitor cells or isolated from peripheral blood of healthy donors are protease poor, DCs derived in vitro from monocytes (MDDCs) are more similar to macrophages (M Phis) in protease content. Unlike other DCs, MDDCs also fail to reduce their intralysosomal pH in response to maturation stimuli. Indeed, functional characterization of lysosomal proteolysis indicates that MDDCs are comparable to M Phis in the rapid degradation of antigen while other human DC subtypes are attenuated in this capacity. CONCLUSIONS/SIGNIFICANCE Human DCs are comparable to murine DCs in exhibiting a markedly reduced level of lysosomal proteolysis. However, as an important exception to this, human MDDCs stand apart from all other DCs by a heightened capacity for proteolysis that resembles that of M Phis. Thus, caution should be exercised when using human MDDCs as a model for DC function and cell biology.
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Affiliation(s)
- Nathanael McCurley
- Departments of Cell Biology and Immunobiology, Ludwig Institute for Cancer Research, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Emory Vaccine Center and Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia, United States of America
| | - Ira Mellman
- Departments of Cell Biology and Immunobiology, Ludwig Institute for Cancer Research, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Genentech, South San Francisco, California, United States of America
- * E-mail:
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100
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Best QA, Xu R, McCarroll ME, Wang L, Dyer DJ. Design and investigation of a series of rhodamine-based fluorescent probes for optical measurements of pH. Org Lett 2010; 12:3219-21. [PMID: 20572677 PMCID: PMC2925113 DOI: 10.1021/ol1011967] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of structurally similar fluorescent probes (1-4), synthesized from rhodamine B, were designed to optically measure pH. Each probe had a unique "off-on" response as the solution went from basic to acidic. Probes 1-3 exhibited a spirocyclic quenching of the pyronin B fluorophore, whereas probe 4 was quenched by PET from the amine moiety.
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Affiliation(s)
- Quinn A. Best
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois 62901
| | - Ruisong Xu
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois 62901
| | - Matthew E. McCarroll
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois 62901
| | - Lichang Wang
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois 62901
| | - Daniel J. Dyer
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois 62901
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