1
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Krasecki V, Sharma A, Cavell AC, Forman C, Guo SY, Jensen ET, Smith MA, Czerwinski R, Friederich P, Hickman RJ, Gianneschi N, Aspuru-Guzik A, Cronin L, Goldsmith RH. The Role of Experimental Noise in a Hybrid Classical-Molecular Computer to Solve Combinatorial Optimization Problems. ACS CENTRAL SCIENCE 2023; 9:1453-1465. [PMID: 37521801 PMCID: PMC10375572 DOI: 10.1021/acscentsci.3c00515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Indexed: 08/01/2023]
Abstract
Chemical and molecular-based computers may be promising alternatives to modern silicon-based computers. In particular, hybrid systems, where tasks are split between a chemical medium and traditional silicon components, may provide access and demonstration of chemical advantages such as scalability, low power dissipation, and genuine randomness. This work describes the development of a hybrid classical-molecular computer (HCMC) featuring an electrochemical reaction on top of an array of discrete electrodes with a fluorescent readout. The chemical medium, optical readout, and electrode interface combined with a classical computer generate a feedback loop to solve several canonical optimization problems in computer science such as number partitioning and prime factorization. Importantly, the HCMC makes constructive use of experimental noise in the optical readout, a milestone for molecular systems, to solve these optimization problems, as opposed to in silico random number generation. Specifically, we show calculations stranded in local minima can consistently converge on a global minimum in the presence of experimental noise. Scalability of the hybrid computer is demonstrated by expanding the number of variables from 4 to 7, increasing the number of possible solutions by 1 order of magnitude. This work provides a stepping stone to fully molecular approaches to solving complex computational problems using chemistry.
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Affiliation(s)
- Veronica
K. Krasecki
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Abhishek Sharma
- Department
of Chemistry, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Andrew C. Cavell
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Christopher Forman
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Si Yue Guo
- Department
of Chemistry, University of Toronto, Toronto, Ontario MS5 3H6, Canada
| | - Evan Thomas Jensen
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Mackinsey A. Smith
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Rachel Czerwinski
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Pascal Friederich
- Department
of Chemistry, University of Toronto, Toronto, Ontario MS5 3H6, Canada
| | - Riley J. Hickman
- Department
of Chemistry, University of Toronto, Toronto, Ontario MS5 3H6, Canada
| | - Nathan Gianneschi
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Alán Aspuru-Guzik
- Department
of Chemistry, University of Toronto, Toronto, Ontario MS5 3H6, Canada
| | - Leroy Cronin
- Department
of Chemistry, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Randall H. Goldsmith
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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2
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Hudson ME, Sewell MA. Ocean acidification impacts sperm swimming performance and pHi in the New Zealand sea urchin Evechinus chloroticus. J Exp Biol 2022; 225:276137. [PMID: 35899479 DOI: 10.1242/jeb.243670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 07/20/2022] [Indexed: 11/20/2022]
Abstract
In sea urchins, spermatozoa are stored in the gonads in hypercapnic conditions (pH<7.0). During spawning, sperm are diluted in seawater of pH>8.0, and there is an alkalinization of the sperm's internal pH (pHi) through the release of CO2 and H+. Previous research has shown that when pHi is above 7.2-7.3, the dynein ATPase flagellar motors are activated, and the sperm become motile. It has been hypothesised that ocean acidification (OA), which decreases the pH of seawater, may have a narcotic effect on sea urchin sperm by impairing the ability to regulate pHi, resulting in decreased motility and swimming speed. Here we use data collected from the same individuals to test the relationship between pHi and sperm motility/performance in the New Zealand sea urchin Evechinus chloroticus (Valenciennes) under near- (2100) and far-future (2150) atmospheric pCO2 conditions (RCP 8.5: pH 7.77, 7.51). Decreasing seawater pH significantly negatively impacted the proportion of motile sperm), and four of the six computer-assisted sperm analysis (CASA) sperm performance measures. In control conditions, sperm had an activated pHi of 7.52. E. chloroticus sperm could not defend pHi. in future OA conditions; there was a stepped decrease in the pHi at pH 7.77, with no significant difference in mean pHi between pH 7.77 and 7.51. Paired measurements in the same males showed a positive relationship between pHi and sperm motility, but with a significant difference in the response between males. Differences in motility and sperm performance in OA conditions may impact fertilization success in a future ocean.
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Affiliation(s)
- Michael E Hudson
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.,Institute of Marine Science, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Mary A Sewell
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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3
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Beltrán LR, Sterneder S, Hasural A, Paetz S, Hans J, Ley JP, Somoza V. Reducing the Bitter Taste of Pharmaceuticals Using Cell-Based Identification of Bitter-Masking Compounds. Pharmaceuticals (Basel) 2022; 15:ph15030317. [PMID: 35337115 PMCID: PMC8953435 DOI: 10.3390/ph15030317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/20/2022] [Accepted: 03/03/2022] [Indexed: 02/04/2023] Open
Abstract
The palatability of a pharmaceutical preparation is a significant obstacle in developing a patient-friendly dosage form. Bitter taste is an important factor for patients in (i) selecting a certain drug from generic products available in the market and (ii) adhering to a therapeutic regimen. The various methods developed for identification of bitter tasting and bitter-taste modulating compounds present a number of limitations, ranging from limited sensitivity to lack of close correlations with sensory data. In this study, we demonstrate a fluorescence-based assay, analyzing the bitter receptor TAS2R-linked intracellular pH (pHi) of human gastric parietal (HGT-1) cells as a suitable tool for the identification of bitter tasting and bitter-taste modulating pharmaceutical compounds and preparations, which resembles bitter taste perception. Among the fluorometric protocols established to analyze pHi changes, one of the most commonly employed assays is based on the use of the pH-sensitive dye SNARF-1 AM. This methodology presents some limitations; over time, the assay shows a relatively low signal amplitude and sensitivity. Here, the SNARF-1 AM methodology was optimized. The identified bicarbonate extrusion mechanisms were partially inhibited, and measurements were carried out in a medium with lower intrinsic fluorescence, with no need for controlling external CO2 levels. We applied the assay for the screening of flavonoids as potential bitter-masking compounds for guaifenesin, a bitter-tasting antitussive drug. Our findings revealed that eriodictyol, hesperitin and phyllodulcin were the most potent suitable candidates for bitter-masking activity, verified in a human sensory trial.
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Affiliation(s)
- Leopoldo Raul Beltrán
- Department of Physiological Chemistry, University of Vienna, 1090 Vienna, Austria; (L.R.B.); (S.S.); (A.H.)
| | - Sonja Sterneder
- Department of Physiological Chemistry, University of Vienna, 1090 Vienna, Austria; (L.R.B.); (S.S.); (A.H.)
| | - Ayse Hasural
- Department of Physiological Chemistry, University of Vienna, 1090 Vienna, Austria; (L.R.B.); (S.S.); (A.H.)
| | - Susanne Paetz
- Symrise AG, Ingredient Research Flavor & Nutrition, 37603 Holzminden, Germany; (S.P.); (J.H.); (J.P.L.)
| | - Joachim Hans
- Symrise AG, Ingredient Research Flavor & Nutrition, 37603 Holzminden, Germany; (S.P.); (J.H.); (J.P.L.)
| | - Jakob Peter Ley
- Symrise AG, Ingredient Research Flavor & Nutrition, 37603 Holzminden, Germany; (S.P.); (J.H.); (J.P.L.)
| | - Veronika Somoza
- Department of Physiological Chemistry, University of Vienna, 1090 Vienna, Austria; (L.R.B.); (S.S.); (A.H.)
- Leibniz-Institute of Food Systems Biology at the Technical University of Munich, 85354 Freising, Germany
- Nutritional Systems Biology, Technical University of Munich, 85354 Freising, Germany
- Correspondence: ; Tel.: +43-1-4277-70601
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4
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Dolatkhah M, Hashemzadeh N, Barar J, Adibkia K, Aghanejad A, Barzegar-Jalali M, Omidian H, Omidi Y. Stimuli-responsive graphene oxide and methotrexate-loaded magnetic nanoparticles for breast cancer-targeted therapy. Nanomedicine (Lond) 2021; 16:2155-2174. [PMID: 34565179 DOI: 10.2217/nnm-2021-0094] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Aim: Nanocomposites of graphene oxide (GO) loaded with PEGylated superparamagnetic iron oxide nanoparticles and grafted with methotrexate and stimuli-responsive linkers (GO-SPION-MTX) were developed for photothermal and chemotherapy of breast cancer. Methods: PEGylated SPIONs were synthesized and conjugated with chemotherapeutic targeting agent MTX, which were then loaded on GO to prepare GO-SPION-MTX nanocomposites. To evaluate the photothermal effect of the nanocomposites, they were examined in breast cancer cell lines with low doses of near-infrared (NIR) laser radiation with/without acetazolamide. Results: The GO-SPION-MTX nanocomposites were found to be internalized by the folate-receptor-positive cancer cells and induce high cytotoxicity on exposure to NIR laser rays. Conclusion: Our findings suggest that the GO-SPION-MTX nanocomposite can potentially be used as a multimodal nanomedicine/theranostic against breast cancer.
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Affiliation(s)
- Mitra Dolatkhah
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran.,Student Research Committee, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Pharmaceutics, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Nastaran Hashemzadeh
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran.,Student Research Committee, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Pharmaceutics, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Jaleh Barar
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Pharmaceutics, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Khosro Adibkia
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Pharmaceutics, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ayuob Aghanejad
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Barzegar-Jalali
- Department of Pharmaceutics, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hossein Omidian
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL 33328, USA
| | - Yadollah Omidi
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL 33328, USA
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5
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Cancer and pH Dynamics: Transcriptional Regulation, Proteostasis, and the Need for New Molecular Tools. Cancers (Basel) 2020; 12:cancers12102760. [PMID: 32992762 PMCID: PMC7601256 DOI: 10.3390/cancers12102760] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 12/11/2022] Open
Abstract
An emerging hallmark of cancer cells is dysregulated pH dynamics. Recent work has suggested that dysregulated intracellular pH (pHi) dynamics enable diverse cancer cellular behaviors at the population level, including cell proliferation, cell migration and metastasis, evasion of apoptosis, and metabolic adaptation. However, the molecular mechanisms driving pH-dependent cancer-associated cell behaviors are largely unknown. In this review article, we explore recent literature suggesting pHi dynamics may play a causative role in regulating or reinforcing tumorigenic transcriptional and proteostatic changes at the molecular level, and discuss outcomes on tumorigenesis and tumor heterogeneity. Most of the data we discuss are population-level analyses; lack of single-cell data is driven by a lack of tools to experimentally change pHi with spatiotemporal control. Data is also sparse on how pHi dynamics play out in complex in vivo microenvironments. To address this need, at the end of this review, we cover recent advances for live-cell pHi measurement at single-cell resolution. We also discuss the essential role for tool development in revealing mechanisms by which pHi dynamics drive tumor initiation, progression, and metastasis.
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6
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Yudovich S, Shani L, Grupi A, Bar-Elli O, Steinitz D, Oron D, Weiss S. Ratiometric widefield imaging with spectrally balanced detection. BIOMEDICAL OPTICS EXPRESS 2019; 10:5385-5394. [PMID: 31646053 PMCID: PMC6788590 DOI: 10.1364/boe.10.005385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/12/2019] [Accepted: 08/29/2019] [Indexed: 06/10/2023]
Abstract
Ratiometric imaging is an invaluable tool for quantitative microscopy, allowing for robust detection of FRET, anisotropy, and spectral shifts of nano-scale optical probes in response to local physical and chemical variations such as local pH, ion composition, and electric potential. In this paper, we propose and demonstrate a scheme for widefield ratiometric imaging that allows for continuous tuning of the cutoff wavelength between its two spectral channels. This scheme is based on angle-tuning the image splitting dichroic beamsplitter, similar to previous works on tunable interference filters. This configuration allows for ratiometric imaging of spectrally heterogeneous samples, which require spectral tunability of the detection path in order to achieve good spectrally balanced ratiometric detection.
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Affiliation(s)
- Shimon Yudovich
- Department of Physics, Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, 52900, Israel
| | - Lior Shani
- Department of Physics, Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, 52900, Israel
| | - Asaf Grupi
- Department of Physics, Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, 52900, Israel
| | - Omri Bar-Elli
- Department of Physics of Complex Systems, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Dan Steinitz
- Department of Physics of Complex Systems, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Dan Oron
- Department of Physics of Complex Systems, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Shimon Weiss
- Department of Physics, Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, 52900, Israel
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
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7
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Zopun M, Liszt KI, Stoeger V, Behrens M, Redel U, Ley JP, Hans J, Somoza V. Human Sweet Receptor T1R3 is Functional in Human Gastric Parietal Tumor Cells (HGT-1) and Modulates Cyclamate and Acesulfame K-Induced Mechanisms of Gastric Acid Secretion. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:4842-4852. [PMID: 29665689 DOI: 10.1021/acs.jafc.8b00658] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The noncaloric sweeteners (NCSs) cyclamate (Cycl) and acesulfame K (AceK) are widely added to foods and beverages. Little is known about their impact on gastric acid secretion (GAS), which is stimulated by dietary protein and bitter-tasting compounds. Since Cycl and AceK have a bitter off taste in addition to their sweet taste, we hypothesized they modulate mechanisms of GAS in human gastric parietal cells (HGT-1). HGT-1 cells were exposed to sweet tastants (50 mM of glucose, d-threonine, Cycl, or AceK) and analyzed for their intracellular pH index (IPX), as an indicator of proton secretion by means of a pH-sensitive dye, and for mRNA levels of GAS-associated genes by RT-qPCR. Since the NCSs act via the sweet taste-sensing receptor T1R2/T1R3, mRNA expression of the corresponding genes was analyzed in addition to immunocytochemical localization of the T1R2 and T1R3 receptor proteins. Exposure of HGT-1 cells to AceK or d-threonine increased the IPX to 0.60 ± 0.05 and 0.80 ± 0.04 ( P ≤ 0.05), respectively, thereby indicating a reduced secretion of protons, whereas Cycl demonstrated the opposite effect with IPX values of -0.69 ± 0.08 ( P ≤ 0.05) compared to controls (IPX = 0). Cotreatment with the T1R3-inhibitor lactisole as well as a TAS1R3 siRNA knock-down approach reduced the impact of Cycl, AceK, and d-thr on proton release ( P ≤ 0.05), whereas cotreatment with 10 mM glucose enhanced the NCS-induced effect ( P ≤ 0.05). Overall, we demonstrated Cycl and AceK as modulators of proton secretion in HGT-1 cells and identified T1R3 as a key element in this response.
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Affiliation(s)
- Muhammet Zopun
- Faculty of Chemistry, Department of Physiological Chemistry , University of Vienna , Althanstraße 14 , Vienna 1090 , Austria
| | - Kathrin I Liszt
- Faculty of Chemistry, Christian Doppler Laboratory for Bioactive Aroma Compounds , University of Vienna , Althanstraße 14 , Vienna 1090 , Austria
| | - Verena Stoeger
- Faculty of Chemistry, Christian Doppler Laboratory for Bioactive Aroma Compounds , University of Vienna , Althanstraße 14 , Vienna 1090 , Austria
| | - Maik Behrens
- Department of Molecular Genetics , German Institute of Human Nutrition Potsdam-Rehbruecke , Arthur-Scheunert-Allee , 114-116 Nuthetal , Germany
| | - Ulrike Redel
- Department of Molecular Genetics , German Institute of Human Nutrition Potsdam-Rehbruecke , Arthur-Scheunert-Allee , 114-116 Nuthetal , Germany
| | - Jakob P Ley
- Symrise AG , Mühlenfeldstraße 1 , 37603 Holzminden , Germany
| | - Joachim Hans
- Symrise AG , Mühlenfeldstraße 1 , 37603 Holzminden , Germany
| | - Veronika Somoza
- Faculty of Chemistry, Department of Physiological Chemistry , University of Vienna , Althanstraße 14 , Vienna 1090 , Austria
- Faculty of Chemistry, Christian Doppler Laboratory for Bioactive Aroma Compounds , University of Vienna , Althanstraße 14 , Vienna 1090 , Austria
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8
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Gao J, Wang S, Wang Z. High yield, scalable and remotely drug-loaded neutrophil-derived extracellular vesicles (EVs) for anti-inflammation therapy. Biomaterials 2017; 135:62-73. [PMID: 28494264 DOI: 10.1016/j.biomaterials.2017.05.003] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 04/16/2017] [Accepted: 05/01/2017] [Indexed: 01/02/2023]
Abstract
Extracellular vesicles (EVs) are nanoscale membrane-formed compartments naturally secreted from cells, which are intercellular mediators regulating physiology and pathogenesis, therefore they could be a novel therapeutic carrier for targeted delivery. However, the translation of EVs is hindered by the heterogeneous composition, low yield, inefficient drug loading and unlikely scalability. Here we report a strategy to generate EVs using nitrogen cavitation (NC-EVs) that instantly disrupts neutrophils to form nanosized membrane vesicles. NC-EVs are similar to naturally secreted EVs (NS-EVs), but contain less subcellular organelles and nuclear acids. The production of NC-EVs was increased by 16 folds and is easy to scale up for clinical use compared to NS-EVs. To examine the usefulness of NC-EVs as a drug delivery platform, piceatannol (an anti-inflammation drug) was remotely loaded in NC-EVs via the pH gradient. We found that piceatannol-loaded NC-EVs dramatically alleviated acute lung inflammation/injury and sepsis induced by lipopolysaccharide (LPS). Our studies reveal that nitrogen cavitation is a novel approach to efficiently generate EVs from any cell type and could be exploited for personalized nanomedicine.
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Affiliation(s)
- Jin Gao
- Department of Pharmaceutical Sciences, College of Pharmacy, Washington State University, Spokane, WA 99202, USA
| | - Sihan Wang
- Department of Pharmaceutical Sciences, College of Pharmacy, Washington State University, Spokane, WA 99202, USA
| | - Zhenjia Wang
- Department of Pharmaceutical Sciences, College of Pharmacy, Washington State University, Spokane, WA 99202, USA.
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9
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Żurawik TM, Pomorski A, Belczyk-Ciesielska A, Goch G, Niedźwiedzka K, Kucharczyk R, Krężel A, Bal W. Revisiting Mitochondrial pH with an Improved Algorithm for Calibration of the Ratiometric 5(6)-carboxy-SNARF-1 Probe Reveals Anticooperative Reaction with H+ Ions and Warrants Further Studies of Organellar pH. PLoS One 2016; 11:e0161353. [PMID: 27557123 PMCID: PMC4996429 DOI: 10.1371/journal.pone.0161353] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 08/03/2016] [Indexed: 11/18/2022] Open
Abstract
Fluorescence measurements of pH and other analytes in the cell rely on accurate calibrations, but these have routinely used algorithms that inadequately describe the properties of indicators. Here, we have established a more accurate method for calibrating and analyzing data obtained using the ratiometric probe 5(6)-carboxy-SNARF-1. We tested the implications of novel approach to measurements of pH in yeast mitochondria, a compartment containing a small number of free H+ ions. Our findings demonstrate that 5(6)-carboxy-SNARF-1 interacts with H+ ions inside the mitochondria in an anticooperative manner (Hill coefficient n of 0.5) and the apparent pH inside the mitochondria is ~0.5 unit lower than had been generally assumed. This result, at odds with the current consensus on the mechanism of energy generation in the mitochondria, is in better agreement with theoretical considerations and warrants further studies of organellar pH.
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Affiliation(s)
- Tomasz Michał Żurawik
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
| | - Adam Pomorski
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14A, 50-383, Wrocław, Poland
| | | | - Grażyna Goch
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
| | - Katarzyna Niedźwiedzka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
| | - Róża Kucharczyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
| | - Artur Krężel
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14A, 50-383, Wrocław, Poland
- * E-mail: (AK); (WB)
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
- * E-mail: (AK); (WB)
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10
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Meseck SL, Alix JH, Swiney KM, Long WC, Wikfors GH, Foy RJ. Ocean Acidification Affects Hemocyte Physiology in the Tanner Crab (Chionoecetes bairdi). PLoS One 2016; 11:e0148477. [PMID: 26859148 PMCID: PMC4747553 DOI: 10.1371/journal.pone.0148477] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 01/20/2016] [Indexed: 11/28/2022] Open
Abstract
We used flow cytometry to determine if there would be a difference in hematology, selected immune functions, and hemocyte pH (pHi), under two different, future ocean acidification scenarios (pH = 7.50, 7.80) compared to current conditions (pH = 8.09) for Chionoecetes bairdi, Tanner crab. Hemocytes were analyzed after adult Tanner crabs were held for two years under continuous exposure to acidified ocean water. Total counts of hemocytes did not vary among control and experimental treatments; however, there were significantly greater number of dead, circulating hemocytes in crabs held at the lowest pH treatment. Phagocytosis of fluorescent microbeads by hemocytes was greatest at the lowest pH treatment. These results suggest that hemocytes were dying, likely by apoptosis, at a rate faster than upregulated phagocytosis was able to remove moribund cells from circulation at the lowest pH. Crab hemolymph pH (pHe) averaged 8.09 and did not vary among pH treatments. There was no significant difference in internal pH (pHi) within hyalinocytes among pH treatments and the mean pHi (7.26) was lower than the mean pHe. In contrast, there were significant differences among treatments in pHi of the semi-granular+granular cells. Control crabs had the highest mean semi-granular+granular pHi compared to the lowest pH treatment. As physiological hemocyte functions changed from ambient conditions, interactions with the number of eggs in the second clutch, percentage of viable eggs, and calcium concentration in the adult crab shell was observed. This suggested that the energetic costs of responding to ocean acidification and maintaining defense mechanisms in Tanner crab may divert energy from other physiological processes, such as reproduction.
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Affiliation(s)
- Shannon L. Meseck
- National Ocean and Atmospheric Administration, National Marine Fisheries Services, Northeaster Fisheries Science Center, Milford, Connecticut, United States of America
- * E-mail:
| | - Jennifer H. Alix
- National Ocean and Atmospheric Administration, National Marine Fisheries Services, Northeaster Fisheries Science Center, Milford, Connecticut, United States of America
| | - Katherine M. Swiney
- Kodiak Laboratory, Resource Assessment and Conservation Engineering Division, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Kodiak, Alaska, United States of America
| | - W. Christopher Long
- Kodiak Laboratory, Resource Assessment and Conservation Engineering Division, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Kodiak, Alaska, United States of America
| | - Gary H. Wikfors
- National Ocean and Atmospheric Administration, National Marine Fisheries Services, Northeaster Fisheries Science Center, Milford, Connecticut, United States of America
| | - Robert J. Foy
- Kodiak Laboratory, Resource Assessment and Conservation Engineering Division, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Kodiak, Alaska, United States of America
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11
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Ghule NV, Kharat K, Bhosale RS, Puyad AL, Bhosale SV, Bhosale SV. The fluorescence detection of autophagosomes in live cells under starvation using core-substituted naphthalenediimide probes. RSC Adv 2016. [DOI: 10.1039/c5ra24133b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We developed NDI-C probe for the analysis of the autophagosomes in live cells. A new flow cytometric method was also developed for the analysis of cell population on the basis of intracellular pH.
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Affiliation(s)
- Namdev V. Ghule
- Polymers and Functional Materials Division
- CSIR – Indian Institute of Chemical Technology
- Hyderabad-500007
- India
| | - Kiran Kharat
- Department of Biotechnology
- Deogiri College
- Aurangabad-431005
- India
| | - Rajesh S. Bhosale
- Polymers and Functional Materials Division
- CSIR – Indian Institute of Chemical Technology
- Hyderabad-500007
- India
| | - Avinash L. Puyad
- School of Chemical Sciences
- Swami Ramanand Teerth Marathwada University
- Nanded-431606
- India
| | | | - Sidhanath V. Bhosale
- Polymers and Functional Materials Division
- CSIR – Indian Institute of Chemical Technology
- Hyderabad-500007
- India
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Gilman-Sachs A, Tikoo A, Akman-Anderson L, Jaiswal M, Ntrivalas E, Beaman K. Expression and role of a2 vacuolar-ATPase (a2V) in trafficking of human neutrophil granules and exocytosis. J Leukoc Biol 2015; 97:1121-31. [PMID: 25877929 DOI: 10.1189/jlb.3a1214-620rr] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 03/20/2015] [Indexed: 12/22/2022] Open
Abstract
Neutrophils kill microorganisms by inducing exocytosis of granules with antibacterial properties. Four isoforms of the "a" subunit of V-ATPase-a1V, a2V, a3V, and a4V-have been identified. a2V is expressed in white blood cells, that is, on the surface of monocytes or activated lymphocytes. Neutrophil associated-a2V was found on membranes of primary (azurophilic) granules and less often on secondary (specific) granules, tertiary (gelatinase granules), and secretory vesicles. However, it was not found on the surface of resting neutrophils. Following stimulation of neutrophils, primary granules containing a2V as well as CD63 translocated to the surface of the cell because of exocytosis. a2V was also found on the cell surface when the neutrophils were incubated in ammonium chloride buffer (pH 7.4) a weak base. The intracellular pH (cytosol) became alkaline within 5 min after stimulation, and the pH increased from 7.2 to 7.8; this pH change correlated with intragranular acidification of the neutrophil granules. Upon translocation and exocytosis, a2V on the membrane of primary granules remained on the cell surface, but myeloperoxidase was secreted. V-ATPase may have a role in the fusion of the granule membrane with the cell surface membrane before exocytosis. These findings suggest that the granule-associated a2V isoform has a role in maintaining a pH gradient within the cell between the cytosol and granules in neutrophils and also in fusion between the surface and the granules before exocytosis. Because a2V is not found on the surface of resting neutrophils, surface a2V may be useful as a biomarker for activated neutrophils.
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Affiliation(s)
- Alice Gilman-Sachs
- Department of Microbiology and Immunology, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
| | - Anjali Tikoo
- Department of Microbiology and Immunology, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
| | - Leyla Akman-Anderson
- Department of Microbiology and Immunology, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
| | - Mukesh Jaiswal
- Department of Microbiology and Immunology, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
| | - Evangelos Ntrivalas
- Department of Microbiology and Immunology, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
| | - Kenneth Beaman
- Department of Microbiology and Immunology, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
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Davis RW, Carvalho BJ, Jones HDT, Singh S. The role of photo-osmotic adaptation in semi-continuous culture and lipid particle release from Dunaliella viridis. JOURNAL OF APPLIED PHYCOLOGY 2015; 27:109-123. [PMID: 25620852 PMCID: PMC4297879 DOI: 10.1007/s10811-014-0331-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 04/25/2014] [Accepted: 04/25/2014] [Indexed: 05/20/2023]
Abstract
Although great efforts have been made to elucidate the phenotypic responses of alga to varying levels of nutrients, osmotic environments, and photosynthetically active radiation intensities, the role of interactions among these variables is largely nebulous. Here, we describe a general method for establishing and maintaining semi-continuous cultures of the halophilic microalgal production strain, Dunaliella viridis, that is independent of variations in salinity and illumination intensity. Using this method, the cultures were evaluated to elucidate the overlapping roles of photosynthetic and osmotic adaptation on the accumulation and compositional variation of the biomass, photosynthetic productivity, and physiological biomarkers, as well as spectroscopic and morphological details at the single-cell level. Correlation matrices defining the relationships among the observables and based on variation of the illumination intensity and salinity were constructed for predicting bioproduct yields for varying culture conditions. Following maintenance of stable cultures for 6-week intervals, phenotypic responses to photo-osmotic drift were explored using a combination of single-cell hyperspectral fluorescence imaging and flow cytometry. In addition to morphological changes, release of lipid microparticles from the cells that is disproportionate to cell lysis was observed under hypotonic drift, indicating the existence of a reversible membrane permeation mechanism in Dunaliella. This phenomenon introduces the potential for low-cost strategies for recovering lipids and pigments from the microalgae by minimizing the requirement for energy intensive harvesting and dewatering of the biomass. The results should be applicable to outdoor culture, where seasonal changes resulting in variable solar flux and precipitation and evaporation rates are anticipated.
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Affiliation(s)
- Ryan W. Davis
- Sandia National Laboratories, Livermore, CA 94551 USA
| | | | - Howland D. T. Jones
- Sandia National Laboratories, Albuquerque, NM 87185 USA
- Present Address: HyperImage Solutions, Rio Rancho, NM 87144 USA
| | - Seema Singh
- Sandia National Laboratories, Livermore, CA 94551 USA
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14
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Shu Z, Xiaochen L, Chuyun D, Man H, Juhua P, Xinghua L, Xin Q, Shaojin D, Wanyun M. Analysis of Cytosolic pH Changes in Thymocytes During Early Apoptosis with Improved Three-Channel Real-Time Fluorescence Imaging. J Fluoresc 2014; 24:1055-9. [DOI: 10.1007/s10895-014-1384-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 03/24/2014] [Indexed: 11/29/2022]
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15
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Asselin J, Roy C, Boudreau D, Messaddeq Y, Bouchareb R, Mathieu P. Supported core–shell nanobiosensors for quantitative fluorescence imaging of extracellular pH. Chem Commun (Camb) 2014; 50:13746-9. [DOI: 10.1039/c4cc06075j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
“Click” chemistry was used to functionalize silica substrates with pH-sensitive nanoparticles, thus producing uniform and highly luminescent ion-sensitive surfaces for quantitative and spatially-resolved extracellular measurements on live cells.
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Affiliation(s)
- Jérémie Asselin
- Département de chimie
- Faculté de Sciences et Génie
- Université Laval
- Québec (QC), Canada G1V 0A6
- Centre d'optique photonique et laser (COPL)
| | - Carl Roy
- Département de chimie
- Faculté de Sciences et Génie
- Université Laval
- Québec (QC), Canada G1V 0A6
- Centre d'optique photonique et laser (COPL)
| | - Denis Boudreau
- Département de chimie
- Faculté de Sciences et Génie
- Université Laval
- Québec (QC), Canada G1V 0A6
- Centre d'optique photonique et laser (COPL)
| | - Younès Messaddeq
- Centre d'optique photonique et laser (COPL)
- Université Laval
- Québec (QC), Canada G1V 0A6
| | - Rihab Bouchareb
- Laboratoire d'études moléculaires des valvulopathies
- Institut universitaire de cardiologie et de pneumologie de Québec
- Université Laval
- Québec (QC), Canada G1V 4G5
| | - Patrick Mathieu
- Laboratoire d'études moléculaires des valvulopathies
- Institut universitaire de cardiologie et de pneumologie de Québec
- Université Laval
- Québec (QC), Canada G1V 4G5
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16
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MA FQ, FENG Y, YANG GY. Ultrahigh-throughput Enzymatic Screening Method Based on Fluorescence-activated Cell Sorting and Its Applications*. PROG BIOCHEM BIOPHYS 2012. [DOI: 10.3724/sp.j.1206.2011.00281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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17
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Lin Y, Wu TY, Gmitro AF. Error analysis of ratiometric imaging of extracellular pH in a window chamber model. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:046004. [PMID: 22559682 PMCID: PMC4572359 DOI: 10.1117/1.jbo.17.4.046004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 01/30/2012] [Accepted: 02/01/2012] [Indexed: 05/31/2023]
Abstract
Ratiometric fluorescence-imaging technique is commonly used to measure extracellular pH in tumors and surrounding tissue within a dorsal skin-fold window chamber. Using a pH-sensitive fluorophore such as carboxy SNARF-1 one can measure pH distributions with high precision. However, it is often observed that the measured pH is lower than expected, with a bias that varies from one image to another. A comprehensive analysis of possible error sources is presented. These error sources include photon noise, estimator bias, instrument errors, temperature, and calibration errors from biological factors.
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Affiliation(s)
- Yuxiang Lin
- University of Arizona, College of Optical Sciences, 1630 East University Boulevard, Tuscon, Arizona 85721
| | - Tzu-Yu Wu
- University of Arizona, College of Optical Sciences, 1630 East University Boulevard, Tuscon, Arizona 85721
| | - Arthur F. Gmitro
- University of Arizona, College of Optical Sciences, 1630 East University Boulevard, Tuscon, Arizona 85721
- University of Arizona, College of Medicine, Department of Radiology, P.O. Box 245067, Tucson, Arizona 85724
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18
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Perl A, Hanczko R, Doherty E. Assessment of mitochondrial dysfunction in lymphocytes of patients with systemic lupus erythematosus. Methods Mol Biol 2012; 900:61-89. [PMID: 22933065 DOI: 10.1007/978-1-60761-720-4_4] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Systemic lupus erythematosus (SLE) is characterized by abnormal activation and cell death signaling within the immune system. Activation, proliferation, or death of cells of the immune system is dependent on controlled reactive oxygen intermediates (ROI) production and ATP synthesis in mitochondria. The mitochondrial transmembrane potential (∆ψ (m)) reflects the energy stored in the electrochemical gradient across the inner mitochondrial membrane which, in turn, is used by F(0)F(1)-ATPase to convert ADP to ATP during oxidative phosphorylation. Mitochondrial hyperpolarization (MHP) and transient ATP depletion represent early and reversible steps in T cell activation and apoptosis. By contrast, T lymphocytes of patients with SLE exhibit elevated ∆ψ (m), i.e., persistent mitochondrial hyperpolarization (MHP), cytoplasmic alkalinization, increased ROI production, as well as diminished levels of intracellular glutathione and ATP. Increased production of nitric oxide has been identified as a cause of MHP and increased mitochondrial biogenesis. Oxidative stress affects signaling through the T cell receptor as well as activity of redox--sensitive caspases. ATP depletion causes diminished activation-induced apoptosis and sensitizes lupus T cells to necrosis. Activation of the mammalian target of rapamycin (mTOR) has recently emerged as a key sensor of MHP and mediator of enhanced Ca(2+) flux in lupus T cells.
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Affiliation(s)
- Andras Perl
- Department of Medicine, State University of New York, Upstate Medical University, College of Medicine, Syracuse, NY, USA.
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19
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Abstract
Flow cytometry has become a standard method for separating individual subsets of cells from a heterogeneous population. Multilaser, multicolour cell sorters are increasingly common and have become more complex in recent years increasing the number of applications available. However, a cell sorting experiment is only as good as the input sample, and the preparation of this is extremely important. This chapter describes the methods used to prepare samples for flow cytometry and how they can be adapted and optimised according to cell type.
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Affiliation(s)
- Derek Davies
- FACS Laboratory, London Research Institute, Cancer Research UK, London, UK.
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20
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Ligasová A, Bulantová J, Sebesta O, Kašný M, Koberna K, Mikeš L. Secretory glands in cercaria of the neuropathogenic schistosome Trichobilharzia regenti - ultrastructural characterization, 3-D modelling, volume and pH estimations. Parasit Vectors 2011; 4:162. [PMID: 21854564 PMCID: PMC3171358 DOI: 10.1186/1756-3305-4-162] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 08/19/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cercariae of schistosomes employ bioactive molecules for penetration into their hosts. These are released from specialized unicellular glands upon stimuli from host skin. The glands were previously well-described in the human pathogen Schistosoma mansoni. As bird schistosomes can also penetrate human skin and cause cercarial dermatitis, our aim was to characterize the architecture and ultrastructure of glands in the neurotropic bird schistosome Trichobilharzia regenti and compare it with S. mansoni. In the context of different histolytic enzymes used by these two species, we focused also on the estimations of gland volumes and pH in T. regenti. RESULTS The architecture and 3-D models of two types of acetabular penetration glands, their ducts and of the head gland are shown here. We characterized secretory vesicles in all three gland types by means of TEM and confirmed accuracy of the models obtained by confocal microscopy. The results of two independent approaches showed that the glands occupy ca. one third of cercarial body volume (postacetabular glands ca. 15%, circumacetabular 12% and head gland 6%). The inner environment within the two types of acetabular glands differed significantly as evidenced by dissimilar ability to bind fluorescent markers and by pH value which was higher in circumacetabular (7.44) than in postacetabular (7.08) glands. CONCLUSIONS As far as we know, this is the first presentation of a 3-D model of cercarial glands and the first exact estimation of the volumes of the three gland types in schistosomes. Our comparisons between T. regenti and S. mansoni implied that the architecture and ultrastructure of the glands is most likely conserved within the family. Only minor variations were found between the two species. It seems that the differences in molecular composition have no effect on general appearance of the secretory cells in TEM. Fluorescent markers employed in this study, distinguishing between secretory vesicles and gland types, can be useful in further studies of mechanisms used by cercariae for host invasion. Results of the first attempts to estimate pH within schistosome glands may help further understanding of regulation of enzymatic activities present within the glands.
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Affiliation(s)
- Anna Ligasová
- Department of Parasitology, Charles University, Prague, Czech Republic
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21
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Singh Y, Dyson J, Garden OA. Use of SNARF-1 to measure murine T cell proliferation in vitro and its application in a novel regulatory T cell suppression assay. Immunol Lett 2011; 140:21-9. [PMID: 21664378 DOI: 10.1016/j.imlet.2011.05.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 05/09/2011] [Accepted: 05/25/2011] [Indexed: 12/22/2022]
Abstract
The green fluorescent dye carboxyfluorescein diacetate succinimidyl ester (CFSE) has been used to track the proliferation of T cells in vitro. Such assays often incorporate more than one population of cells, but the paucity of alternative, spectrally distinct dyes suitable for measuring proliferation has hampered the simultaneous tracking of multiple cell populations; furthermore, CFSE is not compatible with green fluorescent protein (GFP), used to identify T cells in various transgenic mice. We have therefore validated the use of the far red dye seminaphthorhodafluor-1 (SNARF)-1 - originally developed to measure intracellular pH - to track murine T cell proliferation in vitro, demonstrating its ability to distinguish multiple cycles of proliferation over three days in a similar fashion to CFSE. The small changes in fluorescence emission attributed to intracellular alkalinisation of proliferating T cells have minimal impact on the ability of SNARF-1 to track cell division and this dye induces minimal cell death at the concentration used in this application. On the basis of these results, we have developed a novel in vitro murine T cell suppression assay, in which the proliferation of both conventional T cells (Tcons) stained with SNARF-1 and regulatory T cells (Tregs) stained with CFSE can be measured simultaneously. We have also demonstrated that SNARF-1 may be used to stain Tcons in assays of suppression involving 'designer' Tregs, generated by the transduction of CD4(+) T cells with constructs encoding the Foxp3(gfp) fusion protein.
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Affiliation(s)
- Yogesh Singh
- Regulatory T Cell Laboratory, Infection and Immunity Research Group, Department of Veterinary Clinical Sciences, The Royal Veterinary College, Camden Campus, Royal College Street, London, NW1 0TU, United Kingdom
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22
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Zhang X, Jiao Y, Jing X, Wu H, He G, Duan C. pH-sensitive fluorescent sensors based on europium(III) complexes. Dalton Trans 2011; 40:2522-7. [PMID: 21298146 DOI: 10.1039/c0dt01325k] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New europium(III) complexes Eu(TTA)(2)-DSQ and Eu(TTA)(3)-DR1 were designed and synthesized as new fluorescent pH probes (where HDSQ = 5-(dimethylamino)-N-(4-(2-((8-hydroxyquinolin-2-yl)methylene)hydrazinecarbonyl)phenyl)naphthalene-1-sulfonamide, DR1 = N(1)-(4-(dimethylamino)benzylidene)-N(2)-(rhodamine-6G) lactamethylene-diamine and TTA = thiophentrifluoroacetone). Eu(TTA)(2)-DSQ exhibited high sensitivity in monitoring pH changes in neutral aqueous solution with negligible background fluorescence. Eu(TTA)(3)-DR1 comprised a green light emitting Rhodamine 6G fluorophore and a Eu(III) moiety as the origin of red light. These pH-sensitive emitter components have pK(a) values of 5.0 and 7.2 respectively, and exhibit isolated protonated steps within one molecule. Luminescence titrations demonstrate that Eu(TTA)(3)-DR1 was able to detect pH values at both near neutral pH and acidic pH ranges, and was also able to detect pH in both cultured cells and in vivo.
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Affiliation(s)
- Xiaolin Zhang
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, 116012, China
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23
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Hight MR, Nolting DD, McKinley ET, Lander AD, Wyatt SK, Gonyea M, Zhao P, Manning HC. Multispectral fluorescence imaging to assess pH in biological specimens. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:016007. [PMID: 21280913 PMCID: PMC3041815 DOI: 10.1117/1.3533264] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 11/01/2010] [Accepted: 11/17/2010] [Indexed: 05/29/2023]
Abstract
Simple, quantitative assays to measure pH in tissue could improve the study of complicated biological processes and diseases such as cancer. We evaluated multispectral fluorescence imaging (MSFI) to quantify extracellular pH (pHe) in dye-perfused, surgically-resected tumor specimens with commercially available instrumentation. Utilizing a water-soluble organic dye with pH-dependent fluorescence emission (SNARF-4F), we used standard fluorimetry to quantitatively assess the emission properties of the dye as a function of pH. By conducting these studies within the spectroscopic constraints imposed by the appropriate imaging filter set supplied with the imaging system, we determined that correction of the fluorescence emission of deprotonated dye was necessary for accurate determination of pH due to suboptimal excitation. Subsequently, employing a fluorimetry-derived correction factor (CF), MSFI data sets of aqueous dye solutions and tissuelike phantoms could be spectrally unmixed to accurately quantify equilibrium concentrations of protonated (HA) and deprotonated (A-) dye and thus determine solution pH. Finally, we explored the feasibility of MSFI for high-resolution pHe mapping of human colorectal cancer cell-line xenografts. Data presented suggest that MSFI is suitable for quantitative determination of pHe in ex vivo dye-perfused tissue, potentially enabling measurement of pH across a variety of preclinical models of disease.
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Affiliation(s)
- Matthew R Hight
- Vanderbilt University, Department of Physics, Nashville, Tennessee 37221, USA
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24
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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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25
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Weiss C, Rubach M, Lang R, Seebach E, Blumberg S, Frank O, Hofmann T, Somoza V. Measurement of the intracellular ph in human stomach cells: a novel approach to evaluate the gastric acid secretory potential of coffee beverages. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:1976-1985. [PMID: 20070100 DOI: 10.1021/jf903614d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
As the consumption of coffee beverages sometimes is reported to cause gastric irritation, for which an increased stomach acid secretion is one of the promoting factors, different processing technologies such as steam-treatment have been developed to reduce putative stomach irritating compounds. There is evidence-based data neither on the effect of detailed processing variations nor on individual coffee components affecting the proton secretory activity (PSA). This work aimed at developing a screening model suitable for investigating the effects of commercial coffee beverages and components thereof on human parietal cells. Human gastric cancer cells (HGT-1) were treated with reconstituted freeze-dried coffee beverages prepared from customary coffee products such as regular coffee (RC, n = 4), mild bean coffee (MBC, n = 5), stomach friendly coffee (SFC, n = 4), and SFC decaffeinated (SFCD, n = 3). PSA was analyzed by flow cytometry using the pH-sensitive dye SNARF-AM. Treatment of the cells with MBC did not result in a PSA different from RC treatment (p <or= 0.07), whereas cells treated with SFC (p <or= 0.04) or SFCD (p <or= 0.03) showed a significantly lower PSA than those treated with RC. Quantitative and principle component analysis of putative stomach irritating compounds revealed significantly reduced contents of (beta)N-alkanoyl-5-hydroxytryptamides, caffeine, N-methylpyridinium, and catechol in SFCD compared to RC. However, none of these compounds seem to act as the sole key bioactive reducing the PSA of SFCD, since their contents in MBC and SFC samples were not different from those in RC samples, although the PSA of these beverages was significantly lower than that of reconstituted freeze-dried RC beverage.
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Affiliation(s)
- Carola Weiss
- German Research Center for Food Chemistry, Lichtenbergstrasse 4, D-85748 Garching, Germany
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26
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Zhou H, Purdie J, Wang T, Ouyang A. pH measurement and a rational and practical pH control strategy for high throughput cell culture system. Biotechnol Prog 2009; 26:872-80. [DOI: 10.1002/btpr.369] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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27
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Application of a short intracellular pH method to flow cytometry for determining Saccharomyces cerevisiae vitality. Appl Environ Microbiol 2009; 75:5615-20. [PMID: 19581482 DOI: 10.1128/aem.00650-09] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The measurement of yeast's intracellular pH (ICP) is a proven method for determining yeast vitality. Vitality describes the condition or health of viable cells as opposed to viability, which defines living versus dead cells. In contrast to fluorescence photometric measurements, which show only average ICP values of a population, flow cytometry allows the presentation of an ICP distribution. By examining six repeated propagations with three separate growth phases (lag, exponential, and stationary), the ICP method previously established for photometry was transferred successfully to flow cytometry by using the pH-dependent fluorescent probe 5,6-carboxyfluorescein. The correlation between the two methods was good (r(2) = 0.898, n = 18). With both methods it is possible to track the course of growth phases. Although photometry did not yield significant differences between exponentially and stationary phases (P = 0.433), ICP via flow cytometry did (P = 0.012). Yeast in an exponential phase has a unimodal ICP distribution, reflective of a homogeneous population; however, yeast in a stationary phase displays a broader ICP distribution, and subpopulations could be defined by using the flow cytometry method. In conclusion, flow cytometry yielded specific evidence of the heterogeneity in vitality of a yeast population as measured via ICP. In contrast to photometry, flow cytometry increases information about the yeast population's vitality via a short measurement, which is suitable for routine analysis.
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28
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Han J, Loudet A, Barhoumi R, Burghardt RC, Burgess K. A ratiometric pH reporter for imaging protein-dye conjugates in living cells. J Am Chem Soc 2009; 131:1642-3. [PMID: 19146412 DOI: 10.1021/ja8073374] [Citation(s) in RCA: 159] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A molecule that transfers energy through bonds from a donor to an acceptor was prepared with a pH sensitive donor function (fluorescein). At pH values above 6.5, minimal energy transfer occurred, and the probe emitted green fluorescence (ca. 520 nm) when excited at the donor (488 nm). Below pH 6.0 however, energy transfer is efficient; hence excitation at the donor causes emission at the acceptor part (600 nm). This probe was used to image a conjugate of the probe with bovine serum albumin that was imported into endosomes or in the cytosol using the noncovalently bound carrier, Pep-1, at 37 and 4 degrees C, respectively. The more acidic environment of the endosomes was conspicuous from the red fluorescence of the probe.
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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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29
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Abstract
A number of fundamentally important biological processes, such as cell signaling and the initiation of mitosis, are accompanied by a change in intracellular pH. Flow cytometric measurement of pH is a generally straightforward procedure that can be done with any instrument equipped with a 488-nm argon laser. The overall approach is similar to that for calcium: generation of a calibration curve by imparting known changes in pH and interpolation of the test sample pH. This unit presents the traditional calibration method using high-potassium buffers and the proton ionophore nigericin and a more recently developed technique, the pseudo null method, which involves resuspension of cells in defined mixtures of weak acids and weak bases.
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Affiliation(s)
- S Chow
- Ontario Cancer Institute and Princess Margaret Hospital, Toronto, Ontario, Canada
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Siddiqui F, Avery PR, Li CY, Zhang X, LaRue SM, Dewhirst MW, Ullrich RL. Induction of the human heat shock promoter HSP70B by nutritional stress: implications for cancer gene therapy. Cancer Invest 2008; 26:553-61. [PMID: 18584345 DOI: 10.1080/07357900701788015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND We designed and tested, in vitro, an adenoviral construct containing the feline interleukin-12 (IL-12) gene under control of the heat-inducible promoter HSP70B. This construct, AdhspfIL12, was used in a phase I trial in feline soft tissue sarcomas. During the course of our experiments, we noted that IL-12 was being produced in the transfected Crandell Feline Kidney (CrFK) cells under certain conditions even in the absence of hyperthermia. This observation was further explored to identify the cause of this unintended HSP70B induction. MATERIALS AND METHODS We used real-time PCR as a sensitive method to quantitatively detect the presence of even small amounts of IL-12 mRNA. This served as a surrogate indicator of HSP70B induction. Various conditions were tested to induce the heat shock promoter, including nutritional deprivation, radiation and changes in pH. RESULTS Nutritional stresses, specifically the absence of glucose and glutamine, could induce the heat shock promoter, thus, resulting in production of the downstream gene product. Other factors known to trigger the heat shock response, pH change, and reactive oxygen species production were also studied but were not found to contribute to heat shock promoter induction in our setting. CONCLUSIONS The human heat shock promoter (HSP70B) is reported to be an efficient and tightly regulated promoter. We discovered, using sensitive real-time PCR techniques, that it can also be induced in response to cellular nutrient stresses. The pros and cons of this phenomenon and its implications for cancer gene therapy are discussed.
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Affiliation(s)
- Farzan Siddiqui
- Department of Environmental, Colorado State University, Fort Collins, Colorado, USA.
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Skitzki JJ, Muhitch JB, Evans SS. Tracking the elusive lymphocyte: methods of detection during adoptive immunotherapy. Immunol Invest 2007; 36:807-27. [PMID: 18161530 DOI: 10.1080/08820130701712867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Adoptive immunotherapy is an attractive cancer treatment modality due to its capacity to target primary and metastatic lesions with large numbers of tumor-reactive, cytotoxic lymphocytes. The inability of fully armed lymphocytes to traffic into sites of tumor has been proposed as a causal factor for the minimal success observed clinically with this type of immunotherapy. The study of lymphocyte trafficking during adoptive immunotherapy has been limited, despite the existence of a variety of tracking methods. In murine models that simulate adoptive immunotherapy, the use of congenic mice and cell tracking dyes can be used to elucidate lymphocyte trafficking behavior. The continued development of novel technologies will further contribute to this expanding area of research.
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Affiliation(s)
- Joseph J Skitzki
- Department of Immunology, Roswell Park Cancer Institute, Buffalo, New York, USA
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Magg T, Albert MH. Tracking cell proliferation using the far red fluorescent dye SNARF-1. CYTOMETRY PART B-CLINICAL CYTOMETRY 2007; 72:458-64. [PMID: 17397063 DOI: 10.1002/cyto.b.20180] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The [(3)H]thymidine incorporation assay and staining of living cells with fluorescent dyes like carboxyfluorescein diacetate, succinimidyl ester (CFSE) have evolved as valuable methods for studying T cell responses. To assess proliferation of cells already labeled by FITC, CFSE, GFP, or other "green" molecules or to simultaneously track two otherwise indistinguishable cell populations in mixed cell cultures, it would be desirable to have a dye with distinct fluorescent properties for this application. METHODS We analyzed the dilution of the far red fluorescent dye SNARF-1 in proliferating cells by flow cytometric analysis. The results were compared with the CFSE dilution technique as well as the [(3)H]thymidine incorporation assay. RESULTS Staining of primary human lymphocytes revealed that SNARF-1 labeling was equivalent to CFSE for estimating proportions of proliferating cells in stimulated cell cultures and yielded results comparable to [(3)H]thymidine incorporation. We showed that SNARF-1 offers the possibility to simultaneously analyze the proliferation of phenotypically indistinguishable subsets of hematopoietic cells and can also be used to track uniformly proliferating, non hematopoietic cells like HEK293. CONCLUSIONS In summary, we have demonstrated that labeling of cells with SNARF-1 allows for estimating cell proliferation of cells of hematopoietic and non-hematopoietic origin.
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Affiliation(s)
- T Magg
- Department for Pediatric Hematology/Oncology, Dr. von Haunersches Children's Hospital, Munich, Germany
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Murapa P, Gandhapudi S, Skaggs HS, Sarge KD, Woodward JG. Physiological Fever Temperature Induces a Protective Stress Response in T Lymphocytes Mediated by Heat Shock Factor-1 (HSF1). THE JOURNAL OF IMMUNOLOGY 2007; 179:8305-12. [DOI: 10.4049/jimmunol.179.12.8305] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Roberts ES, Wong VA, McManus BE, Marshall MW, Lancianese S, Dorman DC. Changes in intracellular pH play a secondary role in hydrogen sulfide-induced nasal cytotoxicity. Inhal Toxicol 2007; 18:159-67. [PMID: 16399658 DOI: 10.1080/08958370500434156] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Hydrogen sulfide (H(2)S) is a naturally occurring gas that is also associated with several industries. The potential for widespread human inhalation exposure to this toxic gas is recognized as a public health concern. The nasal epithelium is particularly susceptible to H(2)S-induced pathology. Cytochrome oxidase inhibition is postulated as one mechanism of H(2)S toxicity. Another mechanism by which the weak acid H(2)S could cause nasal injury is intracellular acidification and cytotoxicity. To further understand the mechanism by which H(2)S damages the nasal epithelium, nasal respiratory and olfactory epithelial cell isolates and explants from naive rats were loaded with the pH-sensitive intracellular chromophore SNARF-1 and exposed to air or 10, 80, 200, or 400 ppm H(2)S for 90 min. Intracellular pH was measured using flow cytometry or confocal microscopy. Cell lysates were used to quantify total protein and cytochrome oxidase activity. A modest but statistically significant decrease in intracellular pH occurred following exposure of respiratory and olfactory epithelium to 400 ppm H(2)S. Decreased cytochrome oxidase activity was observed following exposure to >10 ppm H(2)S in both respiratory and olfactory epithelia. None of the treatments resulted in cytotoxicity. The intracellular acidification of nasal epithelial cells by high-dose H(2)S exposure and the inhibition of cytochrome oxidase at much lower H(2)S concentrations suggest that changes in intracellular pH play a secondary role in H(2)S-induced nasal injury.
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Affiliation(s)
- E S Roberts
- CIIT Centers for Health Research, Research Triangle Park, North Carolina 27709-2137, USA.
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Janket ML, DeRicco JS, Borowski L, Ayyavoo V. Human immunodeficiency virus (HIV-1) Vpr induced downregulation of NHE1 induces alteration in intracellular pH and loss of ERM complex in target cells. Virus Res 2007; 126:76-85. [PMID: 17349711 PMCID: PMC1950453 DOI: 10.1016/j.virusres.2007.01.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Revised: 01/28/2007] [Accepted: 01/30/2007] [Indexed: 11/30/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) Vpr is known to dysregulate host cellular functions through its interaction with cellular proteins. Using a protein array we assessed Vpr-mediated differential regulation of host cellular proteins expression. Results demonstrated that Vpr differentially regulated host factors that are involved in functions, such as cell proliferation, differentiation and apoptosis. One of the most highly downregulated proteins attained was the sodium hydrogen exchanger, isoform 1 (NHE1), which showed a significant (60%) decrease in HIV-1 Vpr(+) virus infected cells as compared to HIV-1 Vpr(-) virus infected control. NHE1 downregulation further led to acidification of cells and was directly correlated with loss of ezrin, radixin and moesin (ERM) protein complex and decreased AKT phosphorylation. Vpr-mediated NHE1 dyregulation is in part through GR pathway as GR antagonist, mifepristone reversed Vpr-induced NHE1 downregulation.
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Affiliation(s)
- Michelle L. Janket
- Department of Infectious Diseases & Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA
| | - Jeremy S. DeRicco
- Department of Infectious Diseases & Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA
| | - LuAnn Borowski
- Department of Infectious Diseases & Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA
| | - Velpandi Ayyavoo
- Department of Infectious Diseases & Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA
- *Corresponding author: Velpandi Ayyavoo, Ph.D., University of Pittsburgh, Department of Infectious Diseases & Microbiology, 130 DeSoto Street, Pittsburgh, PA 15261, Phone: (412) 624-3070, Fax: (412) 383-8926,
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Koo MK, Oh CH, Holme AL, Pervaiz S. Simultaneous analysis of steady-state intracellular pH and cell morphology by automated laser scanning cytometry. Cytometry A 2007; 71:87-93. [PMID: 17200954 DOI: 10.1002/cyto.a.20361] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Cytosolic pH (pHi) changes are critical in cellular response to diverse stimuli, including cell survival and death signaling. The potential drawback in flow-based analysis is the inability to simultaneously visualize the cells during pHi measurements. Here, the suitability of laser scanning cytometer (LSC) in pHi measurement was investigated. AIM Using the two extensively reported pH-sensitive fluorescent probes, 2,7-bis(2-Carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and 5-(and-6)-carboxy SNARF-1 acetoxymethyl ester, we evaluated the potential of automated LSC as a platform for simultaneous determination of pHi and cell morphology. The effect of a variety of buffer systems-commonly employed for pHi measurements-on cell morphology before pH clamping with the ionophore, nigericin, was also assessed. METHODS Measurement of cytosolic pH was performed using pH-sensitive fluorescent probes BCECF-AM and SNARF-1. pH clamping was carried out using nigericin and samples were analyzed on the LSC or CyAn ADP Flow Cytometer. RESULTS The pHi clamping conditions were optimized as 140 mM potassium and 10 microM nigericin. The suitable buffers used for pH clamping: 140 mM KCl, 1 mM MgCl2, 2 mM CaCl(2).2H2O, 5 mM glucose, 20 mM MES and 140 mM KCl, 1 mM MgCl2, 2 mM CaCl(2).2H2O, 5 mM glucose, and 20 mM Tris. Results obtained with the LSC strongly correlated with those obtained by flow cytometry. CONCLUSION We report here that LSC is an excellent and highly reproducible platform for pHi determination, and provides the added advantage of simultaneous imaging of cells before, during, and after pH measurements.
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Affiliation(s)
- Mei K Koo
- Department of Physiology, Yong Loo Lin School of Medicine, National University Medical Institutes, Singapore
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Naciri M, Al-Rubeai M. Non-invasive flow cytometric monitoring of pHi in cell culture processes using EGFP. J Immunol Methods 2006; 315:185-90. [PMID: 16963074 DOI: 10.1016/j.jim.2006.07.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 07/12/2006] [Accepted: 07/26/2006] [Indexed: 11/26/2022]
Abstract
We have described a new method for monitoring of cell culture processes using green fluorescent protein (GFP) fluorescent intensity. GFP has been used as a non-invasive fluorescent reporter for various cellular processes. In this study, enhanced (EGFP) was found to be a very sensitive indicator of pHi in in vitro cell culture, and responded rapidly to extracellular pH (pHe) changes. EGFP transfected cells were evaluated for pHi changes by flow cytometry, by measuring EGFP fluorescent intensity, and compared to that of the pH-sensitive fluoroprobe, SNARF. EGFP intensity was found to reflect pHi values of cells at different pHe in the presence of nigericin and was affected by the addition of HCl and NaOH. Significant changes in pHi were detected at different stages of batch culture and when using different cell density and media composition. The EGFP assay can be used to minimise the perturbation of cells and processes under study, thus leading to accurate information about the physiological state of single cells in a population. The results establish the application of EGFP as a non-invasive indicator of pHi for monitoring of mammalian cell culture processes.
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Affiliation(s)
- Mariam Naciri
- School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
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Bond J, Varley J. Use of flow cytometry and SNARF to calibrate and measure intracellular pH in NS0 cells. Cytometry A 2005; 64:43-50. [PMID: 15688357 DOI: 10.1002/cyto.a.20066] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Two calibration methods have been proposed for determining the relation between the fluorescence ratio of a pH-sensitive fluorescent indicator and intracellular pH (pHi). The first method uses nigericin to clamp pHi to external pH (pHe) and the second is the null point method. We compared these different calibration methods, solution conditions, and temperatures by using flow cytometry and the fluorescent dye 1,5- (and-6)-carboxy seminaphtorhodafluor-1-acetoxymethyl ester with an NS0 cell line. METHODS The nigericin method was performed in glucose solutions supplemented with KCl and 2-(N-morpholino)ethane sulphonic acid plus tris(hydroxymethyl)aminomethane (solution 1A), a mixture of K2HPO4/KH2PO4 in glucose-solution supplemented solutions (solution 2A), or bicarbonate buffered growth medium supplemented with K2HPO4/KH2PO4 (solution 2B); this allowed a range of pHe values to be used. The effect of temperature (22 degrees C or 37 degrees C) on the nigericin calibration curve was also investigated. The null point method was performed by using a series of solutions with a mixture of weak acid and base with a known pHi response. RESULTS Using solution 1A as the calibration solution resulted in acidic values of pHi for cells cultured in medium as compared with the values achieved with solution 2A. Using solution 2B did not affect the calibration curve. For the temperatures considered in this study, there was no affect on the calibration curve, but temperature did affect the pHi value of cells in phosphate buffered saline. The pseudo-null point method used with flow cytometry resulted in a calibration curve that was significantly different (P<0.05) from that achieved using the nigericin method. CONCLUSIONS Our data indicates that the choice of calibration solution can affect the reported pHi value; therefore, careful choice of solution is important.
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Affiliation(s)
- Jennifer Bond
- Department of Chemical Engineering and Chemical Technology, Imperial College, London, United Kingdom
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D'Alessio M, De Nicola M, Coppola S, Gualandi G, Pugliese L, Cerella C, Cristofanon S, Civitareale P, Ciriolo MR, Bergamaschi A, Magrini A, Ghibelli L. Oxidative Bax dimerization promotes its translocation to mitochondria independently of apoptosis. FASEB J 2005; 19:1504-6. [PMID: 15972297 DOI: 10.1096/fj.04-3329fje] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Bax is a cytosolic protein, which in response to stressing apoptotic stimuli, is activated and translocates to mitochondria, thus initiating the intrinsic apoptotic pathway. In spite of many studies and the importance of the issue, the molecular mechanisms that trigger Bax translocation are still obscure. We show by computer simulation that the two cysteine residues of Bax may form disulfide bridges, producing conformational changes that favor Bax translocation. Oxidative, nonapoptogenic treatments produce an up-shift of Bax migration compatible with homodimerization, which is reverted by reducing agents; this is accompanied by translocation to mitochondria. Dimers also appear in pure cytosolic fractions of cell lysates treated with H2O2, showing that Bax dimerization may take place in the cytosol. Bax dimer-enriched lysates support Bax translocation to isolated mitochondria much more efficiently than untreated lysates, indicating that dimerization may promote Bax translocation. The absence of apoptosis in our system allows the demonstration that Bax moves because of oxidations, even in the absence of apoptosis. This provides the first evidence that Bax dimerization and translocation respond to oxidative stimuli, suggesting a novel role for Bax as a sensor of redox imbalance.
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Affiliation(s)
- M D'Alessio
- Dipartimento di Biología, Universita' di Roma, Tor Vergata, Roma, Italy
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Jöbsis PD, Combs CA, Balaban RS. Two-photon excitation fluorescence pH detection using 2,3-dicyanohydroquinone: a spectral ratiometric approach. J Microsc 2005; 217:260-4. [PMID: 15725129 DOI: 10.1111/j.1365-2818.2005.01442.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The use of 2,3-dicyanohydroquinone (DCHQ) as an emission ratiometric probe of pH in vitro and in fibroblast cells was evaluated using two-photon excitation fluorescence microscopy (TPEFM). In addition, methods for spectrally calibrating the Zeiss LSM510 META spectroscopy system for TPEFM were also developed. The emissions of both the acid and base forms of DCHQ were detectable when using an 800-nm excitation in TPEFM, thereby allowing ratiometric determination of pH. These data suggest that, in contrast to most other emission ratiometric probes, both acid and base forms of DCHQ have similar two-photon cross-sectional areas at 800 nm. Acid (maximum at approximately 457 nm) and base (maximum at approximately 489 nm) DCHQ TPEFM emission spectra were similar to previously reported one-photon excitation emission spectra. Calibration curves for pH were successfully constructed using the ratio of DCHQ emission difference maxima at 460 nm and 512 nm in vitro and in cells. To our knowledge, DCHQ is currently the only effective emission ratiometric pH indicator for two-photon microscopy and may serve as a useful starting point for the development of other TPEFM ratiometric dyes for quantitative measurement of other cell parameters such as Ca2+, Mg2+ or Na+.
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Affiliation(s)
- P D Jöbsis
- Laboratory of Cardiac Energetics, National Heart Lung and Blaood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA.
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Gunawardana SC, Rocheleau JV, Head WS, Piston DW. Nutrient-stimulated insulin secretion in mouse islets is critically dependent on intracellular pH. BMC Endocr Disord 2004; 4:1. [PMID: 15193158 PMCID: PMC434517 DOI: 10.1186/1472-6823-4-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2004] [Accepted: 06/11/2004] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND: Many mechanistic steps underlying nutrient-stimulated insulin secretion (NSIS) are poorly understood. The influence of intracellular pH (pHi) on insulin secretion is widely documented, and can be used as an investigative tool. This study demonstrates previously unknown effects of pHi-alteration on insulin secretion in mouse islets, which may be utilized to correct defects in insulin secretion. METHODS: Different components of insulin secretion in mouse islets were monitored in the presence and absence of forced changes in pHi. The parameters measured included time-dependent potentiation of insulin secretion by glucose, and direct insulin secretion by different mitochondrial and non-mitochondrial secretagogues. Islet pHi was altered using amiloride, removal of medium Cl-, and changing medium pH. Resulting changes in islet pHi were monitored by confocal microscopy using a pH-sensitive fluorescent indicator. To investigate the underlying mechanisms of the effects of pHi-alteration, cellular NAD(P)H levels were measured using two-photon excitation microscopy (TPEM). Data were analyzed using Student's t test. RESULTS: Time-dependent potentiation, a function normally absent in mouse islets, can be unmasked by a forced decrease in pHi. The optimal range of pHi for NSIS is 6.4-6.8. Bringing islet pHi to this range enhances insulin secretion by all mitochondrial fuels tested, reverses the inhibition of glucose-stimulated insulin secretion (GSIS) by mitochondrial inhibitors, and is associated with increased levels of cellular NAD(P)H. CONCLUSIONS: Pharmacological alteration of pHi is a potential means to correct the secretory defect in non-insulin dependent diabetes mellitus (NIDDM), since forcing islet pHi to the optimal range enhances NSIS and induces secretory functions that are normally absent.
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Affiliation(s)
- Subhadra C Gunawardana
- Department of Molecular Physiology and Biophysics, 702 Light Hall, Vanderbilt University, Nashville, TN 37232, USA
| | - Jonathan V Rocheleau
- Department of Molecular Physiology and Biophysics, 702 Light Hall, Vanderbilt University, Nashville, TN 37232, USA
| | - W Steven Head
- Department of Molecular Physiology and Biophysics, 702 Light Hall, Vanderbilt University, Nashville, TN 37232, USA
| | - David W Piston
- Department of Molecular Physiology and Biophysics, 702 Light Hall, Vanderbilt University, Nashville, TN 37232, USA
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Lemasters JJ, Trollinger DR, Qian T, Cascio WE, Ohata H. Confocal imaging of Ca2+, pH, electrical potential, and membrane permeability in single living cells. Methods Enzymol 2003; 302:341-58. [PMID: 12876784 DOI: 10.1016/s0076-6879(99)02031-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- J J Lemasters
- Department of Cell Biology and Anatomy, School of Medicine, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina 27599, USA
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Gergely P, Niland B, Gonchoroff N, Pullmann R, Phillips PE, Perl A. Persistent mitochondrial hyperpolarization, increased reactive oxygen intermediate production, and cytoplasmic alkalinization characterize altered IL-10 signaling in patients with systemic lupus erythematosus. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:1092-101. [PMID: 12097418 PMCID: PMC4020441 DOI: 10.4049/jimmunol.169.2.1092] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Abnormal death signaling in lymphocytes of systemic lupus erythematosus (SLE) patients has been associated with elevation of the mitochondrial transmembrane potential (Delta psi(m)) and increased production of reactive oxygen intermediates (ROI). The resultant ATP depletion sensitizes T cells for necrosis that may significantly contribute to inflammation in patients with SLE. In the present study, the role of mitochondrial signal processing in T cell activation was investigated. CD3/CD28 costimulation of PBL elicited transient mitochondrial hyperpolarization and intracellular pH (pH(i)) elevation, followed by increased ROI production. Baseline Delta psi(m), ROI production, and pH(i) were elevated, while T cell activation-induced changes were blunted in 15 patients with SLE in comparison with 10 healthy donors and 10 rheumatoid arthritis patients. Similar to CD3/CD28 costimulation, treatment of control PBL with IL-3, IL-10, TGF-beta(1), and IFN-gamma led to transient Delta psi(m) elevation. IL-10 had diametrically opposing effects on mitochondrial signaling in lupus and control donors. Unlike healthy or rheumatoid arthritis PBL, cells of lupus patients were resistant to IL-10-induced mitochondrial hyperpolarization. By contrast, IL-10 enhanced ROI production and cell death in lupus PBL without affecting ROI levels and survival of control PBL. Ab-mediated IL-10 blockade or stimulation with antagonistic lymphokine IL-12 normalized baseline and CD3/CD28-induced changes in ROI production and pH(i) with no impact on Delta psi(m) of lupus PBL. The results suggest that mitochondrial hyperpolarization, increased ROI production, and cytoplasmic alkalinization play crucial roles in altered IL-10 responsiveness in SLE.
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Affiliation(s)
- Peter Gergely
- Department of Medicine, State University of New York, College of Medicine, Syracuse, NY 13210
| | - Brian Niland
- Department of Medicine, State University of New York, College of Medicine, Syracuse, NY 13210
- Department of Microbiology and Immunology, State University of New York, College of Medicine, Syracuse, NY 13210
| | - Nick Gonchoroff
- Department of Medicine, State University of New York, College of Medicine, Syracuse, NY 13210
- Department of Pathology, State University of New York, College of Medicine, Syracuse, NY 13210
| | - Rudolf Pullmann
- Department of Medicine, State University of New York, College of Medicine, Syracuse, NY 13210
| | - Paul E. Phillips
- Department of Medicine, State University of New York, College of Medicine, Syracuse, NY 13210
| | - Andras Perl
- Department of Medicine, State University of New York, College of Medicine, Syracuse, NY 13210
- Department of Microbiology and Immunology, State University of New York, College of Medicine, Syracuse, NY 13210
- Address correspondence and reprint requests to Dr. Andras Perl, Department of Medicine, State University of New York, 750 East Adams Street, Syracuse, NY 13210.
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Yang JM, Yang GY, Medina DJ, Vassil AD, Liao J, Hait WN. Treatment of multidrug resistant (MDR1) murine leukemia with P-glycoprotein substrates accelerates the course of the disease. Biochem Biophys Res Commun 1999; 266:167-73. [PMID: 10581184 DOI: 10.1006/bbrc.1999.1757] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The prognosis of patients with tumors expressing P-glycoprotein (P-gp), the MDR1 gene product, is generally poor. It is assumed that this is due to decreased tumor responsiveness that results from decreased drug accumulation. We observed that treatment of animals bearing MDR1-transfected leukemic cells with P-gp substrates (i.e., drugs that are transported by P-gp) significantly worsened host survival compared to treatment with vehicle or non-P-gp substrates. This effect was seen with cancer chemotherapeutic agents (paclitaxel and vincristine) and with the MDR modulator, trans-flupenthixol. To determine the mechanism(s) underlying this observation, we studied alterations in pharmacokinetics, pharmacodynamics, and metastasis. We found that the drug-induced acceleration of disease was associated with increased metastases. P-gp(+) cells treated with P-gp substrates demonstrated several pro-metastatic features, including membrane ruffling and invasion through a hepatocyte monolayer. These results suggest that the treatment of MDR tumors with P-gp substrates may produce changes in malignant behavior that could adversely affect therapeutic outcomes.
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Affiliation(s)
- J M Yang
- The Cancer Institute of New Jersey, University of Medicine and Dentistry of New Jersey/Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA.
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Bladon J, Taylor PC. Extracorporeal photopheresis induces apoptosis in the lymphocytes of cutaneous T-cell lymphoma and graft-versus-host disease patients. Br J Haematol 1999; 107:707-11. [PMID: 10606873 DOI: 10.1046/j.1365-2141.1999.01773.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Extracorporeal photopheresis (ECP) is used in the treatment of T-cell-mediated disorders. However, the mechanism by which ECP achieves its effect remains illusive. Over recent years the ability of ECP to induce apoptosis has been demonstrated by cell culture experiments and retrospective histological analysis. We investigated if apoptosis could be determined in samples tested ex vivo from the UVAR:ECP system. Lymphocytes from 11 patients (six with cutaneous T-cell lymphoma, four with graft-versus-host disease, and one with scleredema) were isolated at three stages of the ECP process: immediately before ECP treatment, from the first buffy coat collected, and post UV irradiation, prior to re-infusion. Using flow cytometry each stage was tested for the early apoptotic markers; Annexin V, ApoptestTM and Carboxy-SNARF-1-AM. Comparisons of the pre-ECP and pre-infusion samples demonstrated a significant increase in apoptotic lymphocytes for all three flow cytometric techniques (P < 0.01). Increases between the pre-ECP and first buffy coat, used as a measure of the extracorporeal manipulation, were much lower. These results demonstrate that ECP directly induces significant levels of apoptosis in lymphocytes of CTCL, GvHD and scleredema patients. The apoptosis of these lymphocytes may contribute to the ECP effect.
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Affiliation(s)
- J Bladon
- Department of Haematology, Rotherham General Hospital, South Yorkshire
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Muller-Borer BJ, Yang H, Marzouk SA, Lemasters JJ, Cascio WE. pHi and pHo at different depths in perfused myocardium measured by confocal fluorescence microscopy. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:H1937-47. [PMID: 9843791 DOI: 10.1152/ajpheart.1998.275.6.h1937] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Confocal microscopy and the H+-sensitive fluorophore carboxyseminaphthorhodafluor-1 (SNARF-1) were used to measure either intracellular pH (pHi) or extracellular pH (pHo) in isolated, arterially perfused rabbit papillary muscles. Single-excitation, dual-emission fluorescent images of the endocardial surface and underlying myocardium to a depth of 300 micron were simultaneously recorded from perfused cylindrical muscles suspended in a controlled atmosphere oriented oblique to the focal plane. Contraction was inhibited by the addition of butanedione monoxime. In separate muscles, pHo was measured during continuous perfusion of SNARF-1 free acid. pHi measurements were made after the muscle was loaded with SNARF-1/AM and the extracellular space was cleared of residual fluorophore. Initial experiments demonstrated the uniformity of ratiometric measurements as a function of pH, image depth, and fluorophore concentration, thereby establishing the potential feasibility of this method for quantitative intramural pH measurements. In subsequent experiments, the method was validated in isolated, arterially perfused rabbit papillary muscle during normal arterial perfusion and as pHi and pHo were altered by applying CO2 externally, exchanging HEPES and bicarbonate buffers, and changing pHi with NH4Cl washout. We conclude that in situ confocal fluorescent microscopy can measure pHi and pHo changes at the endocardial surface and deeper endocardial layers in arterially perfused ventricular myocardium. This method has the potential to study pHi regulation in perfused myocardium at boundaries where diffusion of gases, metabolites, and peptides are expected to modify processes that regulate pHi.
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Affiliation(s)
- B J Muller-Borer
- Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7075, USA
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Liu J, Diwu Z, Klaubert DH. Fluorescent molecular probes III. 2′,7′-Bis-(3-carboxypropyl)-5-(and-6)-carboxyfluorescein (BCPCF): a new polar dual-excitation and dual-emission pH indicator with a pKa of 7.0. Bioorg Med Chem Lett 1997. [DOI: 10.1016/s0960-894x(97)10141-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Trollinger DR, Cascio WE, Lemasters JJ. Selective loading of Rhod 2 into mitochondria shows mitochondrial Ca2+ transients during the contractile cycle in adult rabbit cardiac myocytes. Biochem Biophys Res Commun 1997; 236:738-42. [PMID: 9245725 DOI: 10.1006/bbrc.1997.7042] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A strategy of cold loading of the Ca2+-indicating fluorophore Rhod 2-AM followed by warm incubation was developed to selectively label mitochondria of adult rabbit cardiac myocytes. After electrical stimulation, mitochondrial Rhod 2 fluorescence observed by confocal microscopy increased and then rapidly decayed to baseline. In regions between mitochondria, the fluorescent transients were small or absent. Subsequent addition of calcium ionophore increased mitochondrial but not cytosolic fluorescence, confirming the mitochondrial localization of Rhod 2. These experiments directly demonstrate rapid mitochondrial free Ca2+ transients during the contractile cycle in rabbit cardiac myocytes.
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Affiliation(s)
- D R Trollinger
- Department of Cell Biology and Anatomy, University of North Carolina, Chapel Hill, USA
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Leyval D, Debay F, Engasser JM, Goergen JL. Flow cytometry for the intracellular pH measurement of glutamate producing Corynebacterium glutamicum. J Microbiol Methods 1997. [DOI: 10.1016/s0167-7012(97)00031-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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C-SNARF-1 as a pHi fluoroprobe: discrepancies between conventional and intracellular data do not result from protein interactions. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1997. [DOI: 10.1016/s1011-1344(96)07339-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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