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Bregnhøj M, Thorning F, Ogilby PR. Singlet Oxygen Photophysics: From Liquid Solvents to Mammalian Cells. Chem Rev 2024; 124:9949-10051. [PMID: 39106038 DOI: 10.1021/acs.chemrev.4c00105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/07/2024]
Abstract
Molecular oxygen, O2, has long provided a cornerstone for studies in chemistry, physics, and biology. Although the triplet ground state, O2(X3Σg-), has garnered much attention, the lowest excited electronic state, O2(a1Δg), commonly called singlet oxygen, has attracted appreciable interest, principally because of its unique chemical reactivity in systems ranging from the Earth's atmosphere to biological cells. Because O2(a1Δg) can be produced and deactivated in processes that involve light, the photophysics of O2(a1Δg) are equally important. Moreover, pathways for O2(a1Δg) deactivation that regenerate O2(X3Σg-), which address fundamental principles unto themselves, kinetically compete with the chemical reactions of O2(a1Δg) and, thus, have practical significance. Due to technological advances (e.g., lasers, optical detectors, microscopes), data acquired in the past ∼20 years have increased our understanding of O2(a1Δg) photophysics appreciably and facilitated both spatial and temporal control over the behavior of O2(a1Δg). One goal of this Review is to summarize recent developments that have broad ramifications, focusing on systems in which oxygen forms a contact complex with an organic molecule M (e.g., a liquid solvent). An important concept is the role played by the M+•O2-• charge-transfer state in both the formation and deactivation of O2(a1Δg).
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Affiliation(s)
- Mikkel Bregnhøj
- Department of Chemistry, Aarhus University, 140 Langelandsgade, Aarhus 8000, Denmark
| | - Frederik Thorning
- Department of Chemistry, Aarhus University, 140 Langelandsgade, Aarhus 8000, Denmark
| | - Peter R Ogilby
- Department of Chemistry, Aarhus University, 140 Langelandsgade, Aarhus 8000, Denmark
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Goggin FL, Fischer HD. Singlet oxygen signalling and its potential roles in plant biotic interactions. PLANT, CELL & ENVIRONMENT 2024; 47:1957-1970. [PMID: 38372069 DOI: 10.1111/pce.14851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/25/2024] [Accepted: 01/27/2024] [Indexed: 02/20/2024]
Abstract
Singlet oxygen (SO) is among the most potent reactive oxygen species, and readily oxidizes proteins, lipids and DNA. It can be generated at the plant surface by phototoxins in the epidermis, acting as a direct defense against pathogens and herbivores (including humans). SO can also accumulate within mitochondria, peroxisomes, cytosol and the nucleus through multiple enzymatic and nonenzymatic processes. However, the majority of research on intracellular SO generation in plants has focused on transfer of light energy to triplet oxygen by photopigments from the chloroplast. SO accumulates in response to diverse stresses that perturb chloroplast metabolism, and while its high reactivity limits diffusion distances, it participates in retrograde signalling through the EXECUTER1 sensor, generation of carotenoid metabolites and possibly other unknown pathways. SO thereby reprogrammes nuclear gene expression and modulates hormone signalling and programmed cell death. While SO signalling has long been known to regulate plant responses to high-light stress, recent literature also suggests a role in plant interactions with insects, bacteria and fungi. The goals of this review are to provide a brief overview of SO, summarize evidence for its involvement in biotic stress responses and discuss future directions for the study of SO in defense signalling.
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Affiliation(s)
- Fiona L Goggin
- Department of Entomology and Plant Pathology, University of Arkansas System Division of Agriculture, Fayetteville, Arkansas, USA
| | - Hillary D Fischer
- Department of Entomology and Plant Pathology, University of Arkansas System Division of Agriculture, Fayetteville, Arkansas, USA
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Murotomi K, Umeno A, Shichiri M, Tanito M, Yoshida Y. Significance of Singlet Oxygen Molecule in Pathologies. Int J Mol Sci 2023; 24:ijms24032739. [PMID: 36769060 PMCID: PMC9917472 DOI: 10.3390/ijms24032739] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 01/22/2023] [Accepted: 01/26/2023] [Indexed: 02/04/2023] Open
Abstract
Reactive oxygen species, including singlet oxygen, play an important role in the onset and progression of disease, as well as in aging. Singlet oxygen can be formed non-enzymatically by chemical, photochemical, and electron transfer reactions, or as a byproduct of endogenous enzymatic reactions in phagocytosis during inflammation. The imbalance of antioxidant enzymes and antioxidant networks with the generation of singlet oxygen increases oxidative stress, resulting in the undesirable oxidation and modification of biomolecules, such as proteins, DNA, and lipids. This review describes the molecular mechanisms of singlet oxygen production in vivo and methods for the evaluation of damage induced by singlet oxygen. The involvement of singlet oxygen in the pathogenesis of skin and eye diseases is also discussed from the biomolecular perspective. We also present our findings on lipid oxidation products derived from singlet oxygen-mediated oxidation in glaucoma, early diabetes patients, and a mouse model of bronchial asthma. Even in these diseases, oxidation products due to singlet oxygen have not been measured clinically. This review discusses their potential as biomarkers for diagnosis. Recent developments in singlet oxygen scavengers such as carotenoids, which can be utilized to prevent the onset and progression of disease, are also described.
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Affiliation(s)
- Kazutoshi Murotomi
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566, Japan
| | - Aya Umeno
- Department of Ophthalmology, Shimane University Faculty of Medicine, Izumo 693-8501, Japan
| | - Mototada Shichiri
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda 563-8577, Japan
- Correspondence: ; Tel.: +81-72-751-8234
| | - Masaki Tanito
- Department of Ophthalmology, Shimane University Faculty of Medicine, Izumo 693-8501, Japan
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Olchawa MM, Pilat AK, Szewczyk GM, Sarna TJ. Inhibition of phagocytic activity of ARPE-19 cells by free radical mediated oxidative stress. Free Radic Res 2016; 50:887-97. [PMID: 27225587 DOI: 10.1080/10715762.2016.1194519] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Oxidative stress is a main factor responsible for key changes leading to the onset of age-related macular degeneration (ARMD) that occur in the retinal pigment epithelium (RPE), which is involved in phagocytosis of photoreceptor outer segments (POS). In this study, hydrogen peroxide (H2O2), H2O2 and iron ions (Fe) or rose Bengal (RB) in the presence of NADH and Fe were used to model free radical mediated oxidative stress to test if free radicals and singlet oxygen have different efficiency to inhibit phagocytosis of ARPE-19 cells. Free radical mediated oxidative stress was confirmed by HPLC-EC(Hg) measurements of cholesterol hydroperoxides in treated cells. Electron paramagnetic resonance (EPR) spin trapping was employed to detect superoxide anion. Cell survival was analyzed by the MTT assay. Specific phagocytosis of fluorescein-5-isothiocyanate-labeled POS and non-specific phagocytosis of fluorescent beads were measured by flow cytometry. HPLC analysis of cells photosensitized with RB in the presence of NADH and Fe indicated substantial increase in formation of free radical-dependent 7α/7β-hydroperoxides. EPR spin trapping confirmed the photogeneration of superoxide anion in samples enriched with RB, NADH and Fe. For all three protocols sub-lethal oxidative stress induced significant inhibition of the specific phagocytosis of POS. In contrast, non-specific phagocytosis was inhibited only by H2O2 or H2O2 and Fe treatment. Inhibition of phagocytosis was transient and recoverable by 24 h. These results suggest that free radicals may exert similar to singlet oxygen efficiency in inhibiting phagocytosis of RPE cells, and that the effect depends on the location where initial reactive species are formed.
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Affiliation(s)
- Magdalena M Olchawa
- a Department of Biophysics, Faculty of Biochemistry , Biophysics and Biotechnology, Jagiellonian University , Krakow , Poland
| | - Anna K Pilat
- a Department of Biophysics, Faculty of Biochemistry , Biophysics and Biotechnology, Jagiellonian University , Krakow , Poland
| | - Grzegorz M Szewczyk
- a Department of Biophysics, Faculty of Biochemistry , Biophysics and Biotechnology, Jagiellonian University , Krakow , Poland
| | - Tadeusz Jan Sarna
- a Department of Biophysics, Faculty of Biochemistry , Biophysics and Biotechnology, Jagiellonian University , Krakow , Poland
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Allison RR, Patel RM, McLawhorn RA. Radiation oncology: physics advances that minimize morbidity. Future Oncol 2014; 10:2329-44. [DOI: 10.2217/fon.14.176] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
ABSTRACT Radiation therapy has become an ever more successful treatment for many cancer patients. This is due in large part from advances in physics including the expanded use of imaging protocols combined with ever more precise therapy devices such as linear and particle beam accelerators, all contributing to treatments with far fewer side effects. This paper will review current state-of-the-art physics maneuvers that minimize morbidity, such as intensity-modulated radiation therapy, volummetric arc therapy, image-guided radiation, radiosurgery and particle beam treatment. We will also highlight future physics enhancements on the horizon such as MRI during treatment and intensity-modulated hadron therapy, all with the continued goal of improved clinical outcomes.
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Affiliation(s)
- Ron R Allison
- 21st Century Oncology, Inc., 801 WH Smith Blvd, Greenville, NC 27858, USA
| | - Rajen M Patel
- 21st Century Oncology, Inc., 801 WH Smith Blvd, Greenville, NC 27858, USA
| | - Robert A McLawhorn
- 21st Century Oncology, Inc., 801 WH Smith Blvd, Greenville, NC 27858, USA
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Abstract
Photodynamic therapy (PDT) is a light-based intervention with a long and successful clinical track record for both oncology and non-malignancies. In cancer patients, a photosensitizing agent is intravenously, orally or topically applied and allowed time to preferentially accumulate in the tumor region. Light of the appropriate wavelength and intensity to activate the particular photosensitizer employed is then introduced to the tumor bed. The light energy will activate the photosensitizer, which in the presence of oxygen should allow for creation of the toxic photodynamic reaction generating reactive oxygen species. The photodynamic reaction creates a cascading series of events including initiation of apoptotic and necrotic pathways both in tumor and neovasculature, leading to permanent lesion destruction often with upregulation of the immune system. Cutaneous phototoxicity from unintentional sunlight exposure remains the most common morbidity from PDT. This paper will highlight current research and outcomes from the basic science and clinical applications of oncologic PDT and interpret how these findings may lead to enhanced and refined future PDT.
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Affiliation(s)
- Ron R Allison
- 21st Century Oncology, 801 WH Smith Boulevard, Greenville, NC 27834, USA.
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Abstract
This article is a highlight of the paper by Jarvi et al. in this issue of Photochemistry and Photobiology as well as a brief overview of the state of the field of singlet-oxygen ((1) O(2) ) detection in vivo. The in vivo detection of (1) O(2) using its characteristic 1270 nm phosphorescence is technically challenging. Nevertheless, substantial progress has been made in this area. Major advances have included the commercial development of photomultiplier tubes sensitive to 1270 nm light, techniques for spatially resolving the location of (1) O(2) at a subcellular level and more complex mathematical models for interpreting the kinetics of (1) O(2) emission from living cells. It is now recognized that oxygen consumption, photosensitizer bleaching, oxidation of biological molecules and diffusion of (1) O(2) can significantly change the kinetics of (1) O(2) emission from living cells.
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Affiliation(s)
- Jeffrey R Kanofsky
- Medicine and Neurology Service Line, Edward Hines Jr., Department of Veterans Affairs Hospital, Hines, IL, USA.
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Olchawa M, Szewczyk G, Zareba M, Piłat A, Bzowska M, Mikołajczyk T, Sarna T. Sub-lethal photodynamic damage to ARPE-19 cells transiently inhibits their phagocytic activity. Photochem Photobiol 2010; 86:772-80. [PMID: 20492570 DOI: 10.1111/j.1751-1097.2010.00727.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Efficient phagocytosis of photoreceptor outer segments (POS) membranes by retinal pigment epithelium (RPE) plays a key role in biological renewal of these highly peroxidizable structures. Here, we tested whether photodynamic treatment, mediated by merocyanine 540 (MC 540), rose Bengal or a zinc-substituted chlorophyllide inhibited phagocytic activity of ARPE-19 cells in vitro. Specific phagocytosis of fluorescein-5-isothiocyanate-labeled POS isolated from cow retinas and nonspecific phagocytosis of fluorescent polystyrene beads were measured by flow cytometry. Photodynamic treatment, mediated by all three photosensitizers with sub-threshold doses, induced significant inhibition of the cell-specific phagocytosis. The nonspecific phagocytosis was inhibited by photodynamic treatment mediated only by MC 540. The inhibition of phagocytosis was a reversible phenomenon and after 24 h, the photodynamically treated cells exhibited phagocytic activity that was comparable with that of untreated cells. This study provides proof of principle that sub-threshold photodynamic treatment of ARPE-19 cells with appropriate photosensitizers is a convenient experimental approach for in vitro study of the effects of oxidative stress on specific phagocytic activity of RPE cells. We postulate that oxidative damage to key components of the cell phagocytic machinery may be responsible for severe impairment of its activity, which can lead to retinal degeneration.
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Breitenbach T, Kuimova MK, Gbur P, Hatz S, Schack NB, Pedersen BW, Lambert JDC, Poulsen L, Ogilby PR. Photosensitized production of singlet oxygen: spatially-resolved optical studies in single cells. Photochem Photobiol Sci 2009; 8:442-52. [DOI: 10.1039/b809049a] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Hatz S, Poulsen L, Ogilby PR. Time-resolved Singlet Oxygen Phosphorescence Measurements from Photosensitized Experiments in Single Cells: Effects of Oxygen Diffusion and Oxygen Concentration. Photochem Photobiol 2008; 84:1284-90. [DOI: 10.1111/j.1751-1097.2008.00359.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Jiménez-Banzo A, Sagristà ML, Mora M, Nonell S. Kinetics of singlet oxygen photosensitization in human skin fibroblasts. Free Radic Biol Med 2008; 44:1926-34. [PMID: 18355459 DOI: 10.1016/j.freeradbiomed.2008.02.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 02/19/2008] [Accepted: 02/21/2008] [Indexed: 11/20/2022]
Abstract
The roles played by singlet oxygen ((1)O(2)) in photodynamic therapy are not fully understood yet. In particular, the mobility of (1)O(2) within cells has been a subject of debate for the last two decades. In this work, we report on the kinetics of (1)O(2) formation, diffusion, and decay in human skin fibroblasts. (1)O(2) has been photosensitized by two water-soluble porphyrins targeting different subcellular organelles, namely the nucleus and lysosomes, respectively. By recording the time-resolved near-IR phosphorescence of (1)O(2) and that of its precursor the photosensitizer's triplet state, we find that the kinetics of singlet oxygen formation and decay are strongly dependent on the site of generation. (1)O(2) photosensitized in the nucleus is able to escape out of the cells while (1)O(2) photosensitized in the lysosomes is not. Despite showing a lifetime in the microsecond time domain, (1)O(2) decay is largely governed by interactions with the biomolecules within the organelle where it is produced. This observation may reconcile earlier views that singlet oxygen-induced photodamage is highly localized, while its lifetime is long enough to diffuse over long distances within the cells.
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Affiliation(s)
- Ana Jiménez-Banzo
- Grup d'Enginyeria Molecular, Institut Químic de Sarrià, Universitat Ramon Llull, Via Augusta 390, 08017 Barcelona, Spain
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Bilski P, Kukielczak BM, Chignell CF. Photoproduction and Direct Spectral Detection of Singlet Molecular Oxygen (102) in Keratinocytes Stained with Rose Bengal. Photochem Photobiol 2008. [DOI: 10.1111/j.1751-1097.1998.tb02528.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Weitman H, Schatz S, Gottlieb HE, Kobayashi N, Ehrenberg B. Spectroscopic Probing of the Acid-Base Properties and Photosensitization of a Fluorinated Phthalocyanine in Organic Solutions and Liposomes¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0730473spotab2.0.co2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Kochevar IE, Lynch MC, Zhuang S, Lambert CR. Singlet Oxygen, but not Oxidizing Radicals, Induces Apoptosis in HL-60 Cells¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2000)0720548sobnor2.0.co2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Niedre M, Patterson MS, Wilson BC. Direct Near-infrared Luminescence Detection of Singlet Oxygen Generated by Photodynamic Therapy in Cells In Vitro and Tissues In Vivo¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0750382dnildo2.0.co2] [Citation(s) in RCA: 357] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Zebger I, Snyder JW, Andersen LK, Poulsen L, Gao Z, Lambert JDC, Kristiansen U, Ogilby PR. Rapid Communication: Direct Optical Detection of Singlet Oxygen from a Single Cell ¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2004.tb00015.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hatz S, Lambert JDC, Ogilby PR. Measuring the lifetime of singlet oxygen in a single cell: addressing the issue of cell viability. Photochem Photobiol Sci 2007; 6:1106-16. [PMID: 17914485 DOI: 10.1039/b707313e] [Citation(s) in RCA: 189] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Singlet molecular oxygen, O(2)(a(1)Delta(g)), has been detected from single neurons and HeLa cells in time-resolved optical experiments by its 1270 nm phosphorescence (a(1)Delta(g)--> X(3)Sigma(-)(g)) upon irradiation of a photosensitizer incorporated into the cell. The cells were maintained in a buffered medium and their viability was assessed by live/dead assays. To facilitate the detection of singlet oxygen, intracellular H(2)O was replaced with D(2)O by an osmotic de- and rehydration process. The effect of this insult on the cells was likewise assessed. The data indicate that, in the complicated transition from a "live" to "dead" cell, the majority of our cells have the metabolic activity and morphology characteristic of a live cell. Quenching experiments demonstrate that the singlet oxygen lifetime in our cells is principally determined by interactions with intracellular water and not by interactions with other cell constituents. The data indicate that in a viable, metabolically-functioning, and H(2)O-containing cell, the lifetime of singlet oxygen is approximately 3 micros. This is consistent with our previous reports, and confirms that the singlet oxygen lifetime in a cell is much longer than hitherto believed. This implies that, in a cell, singlet oxygen is best characterized as a selective rather than reactive intermediate. This is important when considering roles played by singlet oxygen as a signaling agent and as a component in events that result in cell death. The data reported herein also demonstrate that spatially-resolved optical probes can be used to monitor selected events in the light-induced, singlet-oxygen-mediated death of a single cell.
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Affiliation(s)
- Sonja Hatz
- Department of Chemistry University of Aarhus, DK-8000, Arhus, Denmark
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Kramarenko GG, Wilke WW, Dayal D, Buettner GR, Schafer FQ. Ascorbate enhances the toxicity of the photodynamic action of Verteporfin in HL-60 cells. Free Radic Biol Med 2006; 40:1615-27. [PMID: 16632121 PMCID: PMC2626188 DOI: 10.1016/j.freeradbiomed.2005.12.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Revised: 12/02/2005] [Accepted: 12/23/2005] [Indexed: 01/24/2023]
Abstract
As a reducing agent, ascorbate serves as an antioxidant. However, its reducing function can in some settings initiate an oxidation cascade, i.e., seem to be a "pro-oxidant." This dichotomy also seems to hold when ascorbate is present during photosensitization. Ascorbate can react with singlet oxygen, producing hydrogen peroxide. Thus, if ascorbate is present during photosensitization the formation of highly diffusible hydrogen peroxide could enhance the toxicity of the photodynamic action. On the other hand, ascorbate could decrease toxicity by converting highly reactive singlet oxygen to less reactive hydrogen peroxide, which can be removed via peroxide-removing systems such as glutathione and catalase. To test the influence of ascorbate on photodynamic treatment we incubated leukemia cells (HL-60 and U937) with ascorbate and a photosensitizer (Verteporfin; VP) and examined ascorbic acid monoanion uptake, levels of glutathione, changes in membrane permeability, cell growth, and toxicity. Accumulation of VP was similar in each cell line. Under our experimental conditions, HL-60 cells were found to accumulate less ascorbate and have lower levels of intracellular GSH compared to U937 cells. Without added ascorbate, HL-60 cells were more sensitive to VP and light treatment than U937 cells. When cells were exposed to VP and light, ascorbate acted as an antioxidant in U937 cells, whereas it was a pro-oxidant for HL-60 cells. One possible mechanism to explain these observations is that HL-60 cells express myeloperoxidase activity, whereas in U937 cells it is below the detection limit. Inhibition of myeloperoxidase activity with 4-aminobenzoic acid hydrazide (4-ABAH) had minimal influence on the phototoxicity of VP in HL-60 cells in the absence of ascorbate. However, 4-ABAH decreased the toxicity of ascorbate on HL-60 cells during VP photosensitization, but had no affect on ascorbate toxicity in U937 cells. These data demonstrate that ascorbate increases hydrogen peroxide production by VP and light. This hydrogen peroxide activates myeloperoxidase, producing toxic oxidants. These observations suggest that in some settings, ascorbate may enhance the toxicity of photodynamic action.
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Affiliation(s)
- Galina G. Kramarenko
- Free Radical and Radiation Biology & ESR Facility, EMRB 68, The University of Iowa, Iowa City, IA 52242-1101
| | - Werner W. Wilke
- Free Radical and Radiation Biology & ESR Facility, EMRB 68, The University of Iowa, Iowa City, IA 52242-1101
| | - Disha Dayal
- Free Radical and Radiation Biology & ESR Facility, EMRB 68, The University of Iowa, Iowa City, IA 52242-1101
| | - Garry R. Buettner
- Free Radical and Radiation Biology & ESR Facility, EMRB 68, The University of Iowa, Iowa City, IA 52242-1101
| | - Freya Q. Schafer
- Free Radical and Radiation Biology & ESR Facility, EMRB 68, The University of Iowa, Iowa City, IA 52242-1101
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Skovsen E, Snyder JW, Ogilby PR. Two-Photon Singlet Oxygen Microscopy: The Challenges of Working with Single Cells. Photochem Photobiol 2006; 82:1187-97. [PMID: 16706601 DOI: 10.1562/2006-04-10-ir-868] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A microscope is described in which singlet molecular oxygen, O2(a1deltag), is produced in a femtoliter focal volume via a nonlinear two-photon photosensitized process, and the 1270 nm phosphorescence from this population of O2(a1deltag) is detected in a photon counting experiment. Although two-photon excitation of a sensitizer is less efficient than excitation by a one-photon process, nonlinear excitation has several distinct advantages with respect to the spatial resolution accessible. Pertinent aspects of this two-photon O2(a1deltag) microscope were characterized using bulk solutions of photosensitizers. These data were compared to those obtained from a single biological cell upon linear one-photon excitation of a sensitizer incorporated in the cell. On the basis of the results obtained, we outline the challenges of using nonlinear optical techniques to create O2(aldeltag) at the single cell level and to then optically detect the O2(aldeltag) thus produced in a time-resolved experiment.
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Affiliation(s)
- Esben Skovsen
- Department of Chemistry, University of Aarhus, Arhus DK-8000, Denmark
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Snyder JW, Lambert JDC, Ogilby PR. 5,10,15,20-Tetrakis(N-Methyl-4-Pyridyl)-21H,23H-Porphine (TMPyP) as a Sensitizer for Singlet Oxygen Imaging in Cells: Characterizing the Irradiation-dependent Behavior of TMPyP in a Single Cell†. Photochem Photobiol 2006; 82:177-84. [PMID: 16351325 DOI: 10.1562/2005-05-30-ra-553] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Singlet molecular oxygen, a1Delta(g), can be detected from a single cell by its weak 1270 nm phosphorescence (a1Delta(g)-->X3Sigma(g)-) upon irradiation of the photosensitizer 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-21H,23H-porphine (TMPyP) incorporated into the cell. The behavior of this sensitizer in a cell, and hence the behavior of the associated singlet oxygen phosphorescence signal, depends on the conditions under which the sample is exposed to light. Upon irradiation of a neuron freshly incubated with TMPyP, the intensity of TMPyP fluorescence initially increases and there is a concomitant increase in the singlet oxygen phosphorescence intensity from the cell. These results appear to reflect a photoinduced release of TMPyP bound to DNA in the nucleus of the cell, where TMPyP tends to localize, and the subsequent relocalization of TMPyP to a different microenvironment in the cell. Upon prolonged irradiation of the cell, TMPyP photobleaches and there is a corresponding decrease in the singlet oxygen phosphorescence intensity from the cell. The data reported herein provide insight into key factors that can influence photosensitized singlet oxygen experiments performed on biological samples.
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Affiliation(s)
- John W Snyder
- Department of Chemistry, University of Aarhus, Arhus, Denmark
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Abstract
Singlet oxygen (1O2) is unique amongst reactive oxygen species formed in cells in that it is an excited state molecule with an inherent upper lifetime of 4 micros in water. Whether the lifetime of 1O2 in cells is shortened by reactions with cellular molecules or reaches the inherent maximum value is still unclear. However, even with the maximum lifetime, the diffusion radius is only approximately 220 nm during three lifetimes (approximately 5% 1O2 remaining), much shorter than cellular dimensions indicating that the primary reactions of 1O2 will be subcellularly localized near the site of 1O2 formation. This fact has raised the question of whether spatially resolved cellular responses to 1O2 occur, i.e. whether responses can be initiated by generation and reaction of 1O2 at a particular subcellular location that would not have been produced by 1O2 generation at other subcellular sites. In this paper, we discuss examples of spatially resolved responses initiated by 1O2 as a function of distance from the site of generation of 1O2. Three levels are recognized, namely, a molecular level where the primary oxidation product directly modifies the behavior of a cell, an organelle level where the initial photo-oxidation products initiate mechanisms that are unique to the organelle and the cellular level where mediators diffuse from their site of formation to the target molecules that initiate the response. These examples indicate that, indeed, spatially resolved responses to 'O2 occur in cells.
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Affiliation(s)
- Robert W Redmond
- Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA.
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Snyder JW, Skovsen E, Lambert JDC, Poulsen L, Ogilby PR. Optical detection of singlet oxygen from single cells. Phys Chem Chem Phys 2006; 8:4280-93. [PMID: 16986070 DOI: 10.1039/b609070m] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The lowest excited electronic state of molecular oxygen, singlet molecular oxygen, O(2)(a (1)Delta(g)), is a reactive species involved in many chemical and biological processes. To better understand the roles played by singlet oxygen in biological systems, particularly at the sub-cellular level, optical tools have been developed to create and directly detect this transient state in time- and spatially-resolved experiments from single cells. Data obtained indicate that, contrary to common perception, this reactive species can be quite long-lived in a cell and, as such, can diffuse over appreciable distances including across the cell membrane into the extracellular environment. On one hand, these results demonstrate that the behavior of singlet oxygen in an intact cell can be significantly different from that inferred from model bulk studies. More generally, these results provide a new perspective for mechanistic studies of intra- and inter-cellular signaling and events that ultimately lead to photo-induced cell death.
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Affiliation(s)
- John W Snyder
- Department of Chemistry, Center for Oxygen Microscopy and Imaging, University of Aarhus, DK-8000 Arhus, Denmark
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23
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Snyder JW, Skovsen E, Lambert JDC, Ogilby PR. Subcellular, Time-Resolved Studies of Singlet Oxygen in Single Cells. J Am Chem Soc 2005; 127:14558-9. [PMID: 16231893 DOI: 10.1021/ja055342p] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In time-resolved and spatially resolved experiments, singlet molecular oxygen, O2(a1Deltag), was created in a single nerve cell upon irradiation of a sensitizer incorporated in the cell using a focused laser beam. The singlet oxygen thus produced was detected by its infrared phosphorescence. Data obtained indicate that in both the cytoplasm and the nucleus of the cell, this reactive species is approximately 1-2 orders of magnitude longer-lived than previously believed. The data demonstrate that deactivation of singlet oxygen in the cell is dominated by interactions with the solvent not cellular constituents such as proteins. These results provide a new perspective for mechanistic studies of the role of O2(a1Deltag) in photoinduced cell death and intracellular signaling.
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Affiliation(s)
- John W Snyder
- Department of Chemistry, University of Aarhus, DK-8000 Aarhus, Denmark
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24
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Lavi R, Sinyakov M, Samuni A, Shatz S, Friedmann H, Shainberg A, Breitbart H, Lubart R. ESR detection of 1O2 reveals enhanced redox activity in illuminated cell cultures. Free Radic Res 2005; 38:893-902. [PMID: 15621706 DOI: 10.1080/1071576010001642646] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Low-energy visible light (LEVL) has previously been found to modulate various processes in different biological systems. One explanation for the stimulatory effect of LEVL is light-induced reactive oxygen species formation. In the present study, both sperm and skin cells were illuminated with LEVL and were found to generate singlet oxygen (1O2). The detection of 1O2 was performed using a trapping probe, 2,2,6,6-tetramethyl-4-piperidone, coupled with electron paramagnetic resonance spectroscopy. In addition, we have shown that, together with O2 generation, LEVL illumination increases the reductive capacity of the cells, which explains the difficulties encountered in 1O2 detection. The potential of visible light to change the cellular redox state may explain the recently observed biostimulative effects exerted by LEVL.
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Affiliation(s)
- Ronit Lavi
- Department of Chemistry, Bar-ilan University, Ramat-Gan, Israel
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25
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Skovsen E, Snyder JW, Lambert JDC, Ogilby PR. Lifetime and Diffusion of Singlet Oxygen in a Cell. J Phys Chem B 2005; 109:8570-3. [PMID: 16852012 DOI: 10.1021/jp051163i] [Citation(s) in RCA: 316] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In time- and spatially resolved experiments, singlet molecular oxygen, O(2)(a(1)Delta(g)), was created in a single nerve cell upon irradiation of a sensitizer incorporated in the cell nucleus using a focused laser beam. The singlet oxygen thus produced was detected by its infrared phosphorescence. Data obtained indicate that, contrary to common perception, this reactive species can be quite long-lived in a cell and, as such, can diffuse over appreciable distances including across the cell membrane into the extra-cellular environment. These results provide a new perspective for mechanistic studies of photoinduced cell death and intracellular signaling.
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Affiliation(s)
- Esben Skovsen
- Department of Chemistry, and Department of Physiology, University of Aarhus, DK-8000 Arhus, Denmark
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26
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Baier J, Maier M, Engl R, Landthaler M, Bäumler W. Time-Resolved Investigations of Singlet Oxygen Luminescence in Water, in Phosphatidylcholine, and in Aqueous Suspensions of Phosphatidylcholine or HT29 Cells. J Phys Chem B 2005; 109:3041-6. [PMID: 16851318 DOI: 10.1021/jp0455531] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Singlet oxygen was generated by energy transfer from the photoexcited sensitizer, Photofrin or 9-acetoxy-2,7,12,17-tetrakis-(beta-methoxyethyl)-porphycene (ATMPn), to molecular oxygen. Singlet oxygen was detected time-resolved by its luminescence at 1270 nm in an environment of increasing complexity, water (H2O), pure phosphatidylcholine, phosphatidylcholine in water (lipid suspensions), and aqueous suspensions of living cells. In the case of the lipid suspensions, the sensitizers accumulated in the lipids, whereas the localizations in the cells are the membranes containing phosphatidylcholine. By use of Photofrin, the measured luminescence decay times of singlet oxygen were 3.5 +/- 0.5 micros in water, 14 +/- 2 micros in lipid, 9 +/- 2 micros in aqueous suspensions of lipid droplets, and 10 +/- 3 micros in aqueous suspensions of human colonic cancer cells (HT29). The decay time in cell suspensions was much longer than in water and was comparable to the value in suspensions of phosphatidylcholine. That luminescence signal might be attributed to singlet oxygen decaying in the lipid areas of cellular membranes. The measured luminescence decay times of singlet oxygen excited by ATMPn in pure lipid and lipid suspensions were the same within the experimental error as for Photofrin. In contrast to experiments with Photofrin, the decay time in aqueous suspension of HT29 cells was 6 +/- 2 micros when using ATMPn.
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Affiliation(s)
- Jürgen Baier
- Department of Dermatology, University of Regensburg, Germany, and Institute of Experimental and Applied Physics, University of Regensburg, Germany
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27
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Cao Y, Koo YEL, Koo SM, Kopelman R. Ratiometric Singlet Oxygen Nano-optodes and Their Use for Monitoring Photodynamic Therapy Nanoplatforms. Photochem Photobiol 2005; 81:1489-98. [PMID: 16107183 DOI: 10.1562/2005-05-18-ra-532] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Ratiometric photonic explorers for bioanalysis with biologically localized embedding (PEBBLE) nanoprobes have been developed for singlet oxygen, using organically modified silicate (ORMOSIL) nanoparticles as the matrix. A crucial aspect of these ratiometric singlet-oxygen fluorescent probes is their minute size. The ORMOSIL nanoparticles are prepared via a sol-gel-based process and the average diameter of the resultant particles is about 160 nm. These sensors incorporate the singlet-oxygen-sensitive 9,10-dimethyl anthracene as an indicator dye and a singlet-oxygen-insensitive dye, octaethylporphine, as a reference dye for ratiometric fluorescence-based analysis. We have found experimentally that these nanoprobes have much better sensitivity than does the conventional singlet-oxygen-free dye probe, anthracene-9,10-dipropionic acid disodium salt. The much longer lifetime of singlet oxygen in the ORMOSIL matrix, compared to aqueous solutions, in addition to the relatively high singlet oxygen solubility because of the highly permeable structure and the hydrophobic nature of the outer shell of the ORMOSIL nanoparticles, results in an excellent overall response to singlet oxygen. These nanoprobes have been used to monitor the singlet oxygen produced by "dynamic nanoplatforms" that were developed for photodynamic therapy. The singlet oxygen nanoprobes could potentially be used to quantify the singlet oxygen produced by macrophages.
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Affiliation(s)
- Youfu Cao
- Department of Chemistry, University of Michigan, Ann Arbor 48109, USA
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28
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Snyder JW, Zebger I, Gao Z, Poulsen L, Frederiksen PK, Skovsen E, McIlroy SP, Klinger M, Andersen LK, Ogilby PR. Singlet oxygen microscope: from phase-separated polymers to single biological cells. Acc Chem Res 2004; 37:894-901. [PMID: 15612679 DOI: 10.1021/ar040075y] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The lowest excited electronic state of molecular oxygen, singlet molecular oxygen (a1Deltag), is an intermediate in many chemical and biological processes. Tools and methods have been developed to create singlet-oxygen-based optical images of heterogeneous samples that range from phase-separated polymers to biological cells. Such images provide unique insight into a variety of oxygen-dependent phenomena, including the photoinitiated death of cells.
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Affiliation(s)
- John W Snyder
- Department of Chemistry, University of Aarhus, DK-8000 Arhus, Denmark
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29
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Zebger I, Snyder JW, Andersen LK, Poulsen L, Gao Z, Lambert JDC, Kristiansen U, Ogilby PR. Direct optical detection of singlet oxygen from a single cell. Photochem Photobiol 2004; 79:319-22. [PMID: 15137507 DOI: 10.1562/rc-065r.1] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Singlet oxygen has been detected in single nerve cells by its weak 1270 nm phosphorescence (a1deltag --> X3sigmag-) upon irradiation of a photosensitizer incorporated in the cell. Thus, one can now consider the application of direct optical imaging techniques to mechanistic studies of singlet oxygen at the single-cell level.
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Affiliation(s)
- Ingo Zebger
- Department of Chemistry, University of Aarhus, Arhus, Denmark
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30
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Weitman H, Schatz S, Gottlieb HE, Kobayashi N, Ehrenberg B. Spectroscopic Probing of the Acid–Base Properties and Photosensitization of a Fluorinated Phthalocyanine in Organic Solutions and Liposomes¶. Photochem Photobiol 2001; 73:473-81. [PMID: 11367567 DOI: 10.1562/0031-8655(2001)073<0473:spotab>2.0.co;2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A perfluorinated derivative of phthalocyanine was synthesized as the free base, hexadeca-(2,2,2-trifluoroethoxy) phthalocyanine (H2F48Pc), and as a zinc complex, hexadeca-(2,2,2-trifluoroethoxy)-phthalocyaninatozinc (ZnF48Pc), and their spectroscopic and photochemical properties were studied. The absorption bands are shifted bathochromically relative to simple phthalocyanines, exhibiting the longest wavelength band near 735 nm (H2F48Pc) and 705 (ZnF48Pc). The solvatochromism of both compounds was modeled by Reichardt's ET(30) parameter and Kamlet, Abboud and Taft multiparameter approach. The former, simpler, model was found to be adequate. We found that H2F48Pc undergoes unique basic and acidic titrations in organic solvents. These titration processes are accompanied by spectral changes that are explained on the basis of the chromophore's symmetry. Singular value decomposition was employed to resolve the spectra into the contributions of the species at various stages of protonation and to obtain the equilibrium constants. Nuclear magnetic resonance spectra (1H, 19F and 13C) for the free base were obtained in a tetrahydrofurand8 solution. The carbon spectrum, taken as a function of temperature, provided evidence for the presence of a tautomerization process, which switches the two internal hydrogens between the four central nitrogen atoms. As far as we know, this is the first report of the measurement of the free energy of activation for such process (delta G = 10.6-11.4 kcal mol-1 between 217 and 330 K) for a phthalocyanine, in solution. Like most other phthalocyanines these two compounds also act as photosensitizers and as generators of singlet molecular oxygen. The absolute quantum yields (phi delta) for ZnF48Pc was 0.58 +/- 0.01 in benzene and 0.35 +/- 0.01 in lipid vesicles. H2F48Pc had lower yields, 0.16 and 0.005, respectively. Either protonation or deprotonation of the pyrrole nitrogens in H2F48Pc lowered the phi delta.
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Affiliation(s)
- H Weitman
- Department of Physics, Bar Ilan University, Ramat Gan, Israel
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31
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Affiliation(s)
- W M Sharman
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Quebéc, Canada
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32
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Abstract
In cells under oxidative attack, membrane Ch, through the formation of its signature hydroperoxide and diol products, can serve as a unique detector in situ, allowing discrimination between 1O2 and free radical intermediacy. Of the two techniques described for analyzing Ch oxidation products, TLC with color development suffices for preliminary, mainly qualitative product screening, whereas a high-performance approach such as HPLC-EC(Hg) is advised when maximum resolution and sensitivity of quantitation are necessary. By using these strategies, one can monitor the formation of 1O2, for example, in a biologically relevant milieu (membrane), thus avoiding the difficulties associated with external detection, e.g., by physical means. These approaches would be valuable for assessing reaction mechanisms for various oxidative agents of biomedical importance, including environmental phototoxins and the rapidly emerging family of phototherapeutic drugs. Although photodynamic stress has been emphasized, the methods described should have broad applicability in the elucidation of oxidative mechanisms.
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Affiliation(s)
- A W Girotti
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee 53226, USA
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33
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Kochevar IE, Lynch MC, Zhuang S, Lambert CR. Singlet oxygen, but not oxidizing radicals, induces apoptosis in HL-60 cells. Photochem Photobiol 2000; 72:548-53. [PMID: 11045728 DOI: 10.1562/0031-8655(2000)072<0548:sobnor>2.0.co;2] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Oxidizing species (OS), produced by photosensitization or derived from cytotoxic agents, activate apoptotic pathways. We investigated whether two different OS, formed at the same subcellular sites, have equivalent ability to initiate apoptosis in HL-60 cells. Our previous work showed that absorption of visible light by rose bengal (RB) produces singlet oxygen exclusively, whereas absorption of ultraviolet A produces RB-derived radicals in addition to singlet oxygen. Singlet oxygen, but not the RB-derived radicals, induced nuclear condensation and DNA fragmentation into nucleosome-size fragments in a dose dependent manner. In contrast, the RB-derived radicals caused greater lipid oxidation than singlet oxygen. These results indicate that different OS, produced at the same subcellular sites, do not have the same ability to induce apoptosis and that the ability of an OS to initiate lipid oxidation does not necessarily correlate with its ability to induce apoptosis.
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Affiliation(s)
- I E Kochevar
- Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA.
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34
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Roslaniec M, Weitman H, Freeman D, Mazur Y, Ehrenberg B. Liposome binding constants and singlet oxygen quantum yields of hypericin, tetrahydroxy helianthrone and their derivatives: studies in organic solutions and in liposomes. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2000; 57:149-58. [PMID: 11154081 DOI: 10.1016/s1011-1344(00)00090-7] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The spectroscopy and photophysics of several hypericin and helianthrone derivatives were studied in methanol and when bound to liposomes. The singlet oxygen quantum yields (phi(delta)) were measured indirectly relative to Rose Bengal and hematoporphyrin IX, employing 9,10-dimethylanthracene as a singlet oxygen trap. Hypericin was found to have a phi(delta) of 0.39+/-0.01 in methanol, and 0.35+/-0.05 in lecithin vesicles, in agreement with literature values. A heavy atom effect was evident upon bromination, resulting in phi(delta) for tetrabromohypericin of 0.72+/-0.02, presumably due to enhanced intersystem crossing. Elimination of the anionic hydroxyls by methylation also enhanced phi(delta) to 0.81+/-0.01. Conversely, addition of anionic sulfate groups drastically reduced phi(delta) resulting in phi(delta)'s of 0.12+/-0.01, 0.052+/-0.003 and 0.40+/-0.01 for hypericin disulfonate, hypericin tetrasulfonate and hexamethyl hypericin tetrasulfonate, respectively. The non-sulfonated helianthrones exhibited low phi(delta)'s in solution. The liposome binding constants, Kb, were measured using a spectroscopic assay. Except for hexamethyl hypericin, all non-sulfonated compounds bound well with Kb's ranging from 15.5+/-0.1 to 48.7+/-3.9 (mg/ml)(-1). None of the tetrasulfonated compounds bound, however the hypericin disulfonate had a Kb of 4.1+/-0.2 (mg/ml)(-1). The phi(delta)'s of the compounds capable of binding were measured and, in the case of the hypericin derivatives, were found not to vary dramatically from those in the free state. Liposome-bound helianthrone and dimethyl tetrahydroxy helianthrone both exhibited high phi(delta)'s, i.e. >0.5. The variations in binding constant and sensitization efficiencies are explained in conjunction with the molecular structure. The relevance of the above data to photodynamic therapy is briefly discussed.
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Affiliation(s)
- M Roslaniec
- Department of Physics, Bar Ilan University, Ramat Gan, Israel
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35
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Sobolev AS, Jans DA, Rosenkranz AA. Targeted intracellular delivery of photosensitizers. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2000; 73:51-90. [PMID: 10781829 DOI: 10.1016/s0079-6107(00)00002-x] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- A S Sobolev
- Department of Biophysics, Biological Faculty, Moscow State University, 119899, Moscow, Russia.
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36
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Li HR, Wu LZ, Tung CH. Reactions of Singlet Oxygen with Olefins and Sterically Hindered Amine in Mixed Surfactant Vesicles. J Am Chem Soc 2000. [DOI: 10.1021/ja9917161] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hong-Ru Li
- Contribution from the Institute of Photographic Chemistry, the Chinese Academy of Sciences, Beijing 100101, P. R. China, and Center for Molecular Science, Institute of Chemistry, the Chinese Academy of Sciences, Beijing 100080, P. R. China
| | - Li-Zhu Wu
- Contribution from the Institute of Photographic Chemistry, the Chinese Academy of Sciences, Beijing 100101, P. R. China, and Center for Molecular Science, Institute of Chemistry, the Chinese Academy of Sciences, Beijing 100080, P. R. China
| | - Chen-Ho Tung
- Contribution from the Institute of Photographic Chemistry, the Chinese Academy of Sciences, Beijing 100101, P. R. China, and Center for Molecular Science, Institute of Chemistry, the Chinese Academy of Sciences, Beijing 100080, P. R. China
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37
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Oldham TC, Phillips D. Triplet-state photophysics of aluminium phthalocyanine sensitizer in murine cancer cells. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2000; 55:16-9. [PMID: 10877062 DOI: 10.1016/s1011-1344(00)00017-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Diffuse-reflectance laser flash photolysis has been used to record transient spectra and decay kinetics of the photodynamic therapy sensitizer disulfonated aluminium phthalocyanine in two murine cancer cell lines, P815 derived from white mouse mast cells, and EL4, a lymphoblast derived from black mouse lymphocytes. In contrast to results with bacterial cells and yeasts, no transient other than the triplet state of the sensitizer was detected, suggesting that unlike the case in microbes, Type I electron-transfer processes play no role in the photodestruction of the murine cells studied.
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Affiliation(s)
- T C Oldham
- Departrment of Chemistry, Imperial College of Science, Technology and Medicine, London, UK
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38
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Schafer FQ, Buettner GR. Singlet Oxygen Toxicity Is Cell Line-dependent: A Study of Lipid Peroxidation in Nine Leukemia Cell Lines. Photochem Photobiol 1999. [DOI: 10.1111/j.1751-1097.1999.tb08294.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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39
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Oelckers S, Ziegler T, Michler I, Röder B. Time-resolved detection of singlet oxygen luminescence in red-cell ghost suspensions: concerning a signal component that can be attributed to 1O2 luminescence from the inside of a native membrane. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1999; 53:121-7. [PMID: 10672537 DOI: 10.1016/s1011-1344(99)00137-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
For about ten years, it has been debated whether in principle it is possible to detect 1O2 located within the cell membrane by performing experiments with cell suspensions or even in tissue. In this paper we present our investigations on photosensitized red-cell ghost suspensions (RCGSs) and our strategy for the detection of luminescence of singlet oxygen (1O2) from the inside of the cell membrane. Using a very sensitive apparatus for time-resolved 1O2 detection, a very promising sensitizer and an adequate experimental strategy, a very small amount of the detected luminescence indeed can be attributed to 1O2 from the inside of the ghost membrane.
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Affiliation(s)
- S Oelckers
- Humboldt Universität zu Berlin, Institut für Physik, AG Photobiophysik, Germany
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40
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Affiliation(s)
- Timothy C. Oldham
- Department of Chemistry, Imperial College of Science, Technology and Medicine, South Kensington, London SW7 2AY, U.K
| | - David Phillips
- Department of Chemistry, Imperial College of Science, Technology and Medicine, South Kensington, London SW7 2AY, U.K
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41
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Affiliation(s)
- Peter R. Ogilby
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000, Aarhus, Denmark
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42
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Hadjur C, Lange N, Rebstein J, Monnier P, van den Bergh H, Wagnières G. Spectroscopic studies of photobleaching and photoproduct formation of meta(tetrahydroxyphenyl)chlorin (m-THPC) used in photodynamic therapy. The production of singlet oxygen by m-THPC. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1998. [DOI: 10.1016/s1011-1344(98)00177-8] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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43
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Ehrenberg B, Anderson JL, Foote CS. Kinetics and Yield of Singlet Oxygen Photosensitized by Hypericin in Organic and Biological Media. Photochem Photobiol 1998. [DOI: 10.1111/j.1751-1097.1998.tb02479.x] [Citation(s) in RCA: 145] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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44
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Viola A, Jeunet A, Decreau R, Chanon M, Julliard M. ESR studies of a series of phthalocyanines. Mechanism of phototoxicity. Comparative quantitation of O2-. using ESR spin-trapping and cytochrome c reduction techniques. Free Radic Res 1998; 28:517-32. [PMID: 9702532 DOI: 10.3109/10715769809066889] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ESR experiments with 2,2,6,6-tetramethyl-4-piperidone (4-oxo-TEMP) and the spin-trap 5,5-dimethyl pyrroline-N-oxide (DMPO) have been performed on a series of new phthalocyanines: the bis(tri-n-hexylsiloxy) silicon phthalocyanine ([(nhex)3SiO]2SiPc), the hexadecachloro zinc phthalocyanine (ZnPcCl16), the hexadecachloro aluminum phthalocyanine (AlPcCl16), the hexadecachloro aluminum phthalocyanine sulfate (HSO4AlPcCl16), whose photocytotoxicity has been studied against various leukemic and melanotic cell lines. Type I and Type II pathways occur simultaneously in DMF although the Type II seems to be prevalent. These results are not changed when the bis(tri-n-hexylsiloxy) silicon phthalocyanine is entrapped into liposomes. By contrast, the Type I process is favored in membrane models for all the perchlorinated phthalocyanines. This modified behavior may be accounted on a possible stacking of phthalocyanines in membranes and a preventing effect of axial ligands against aggregation in the case of the bis(tri-n-hexylsiloxy) silicon phthalocyanine. The photodynamic action of zinc perchlorinated phthalocyanine is not dependent on singlet oxygen, phototoxicity of this molecule being essentially mediated by oxygen free radicals. Quantitation of the superoxide radical was accomplished, with good agreement, by two techniques: the cytochrome c reduction and the ESR quantitation based on the double integration of the first derivative of the ESR signal. The disproportionation of the superoxide radical or degradation of the spin-trap seem to be avoided in aprotic solvents such as DMF.
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Affiliation(s)
- A Viola
- Laboratoire AM3-ESA 6009, Faculté des Sciences Saint-Jérôme, Marseille, France
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45
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Ochsner M. Photophysical and photobiological processes in the photodynamic therapy of tumours. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1997; 39:1-18. [PMID: 9210318 DOI: 10.1016/s1011-1344(96)07428-3] [Citation(s) in RCA: 695] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Photodynamic therapy (PDT) is an innovative and attractive modality for the treatment of small and superficial tumours. PDT, as a multimodality treatment procedure, requires both a selective photosensitizer and a powerful light source which matches the absorption spectrum of the photosensitizer. Quadra Logic's Photofrin, a purified haematoporphyrin derivative, is so far the only sensitizer approved for phase III and IV clinical trials. The major drawbacks of this product are the lack of chemical homogeneity and stability, skin phototoxicity, unfavourable physicochemical properties and low selectivity with regard to uptake and retention by tumour vs. normal cells. Second-generation photosensitizers, including the phthalocyanines, show an increased photodynamic efficiency in the treatment of animal tumours and reduced phototoxic side effects. At the time of writing of this article, there were more than half a dozen new sensitizers in or about to start clinical trials. Most available data suggest a common mechanism of action. Following excitation of photosensitizers to long-lived excited singlet and/ or triplet states, the tumour is destroyed either by reactive singlet oxygen species (type II mechanism) and/or radical products (type I mechanism) generated in an energy transfer reaction. The major biological targets of the radicals produced and of singlet oxygen are well known today. Nucleic acids, enzymes and cellular membranes are rapidly attacked and cause the release of a wide variety of pathophysiologically highly reactive products, such as prostaglandins, thromboxanes and leukotrienes. Activation of the complement system and infiltration of immunologically active blood cells into the tumorous region enhance the damaging effect of these aggressive intermediates and ultimately initiate tumour necrosis. The purpose of this review article is to summarize the up-to-date knowledge on the mechanisms responsible for the induction of tumour necrotic reactions.
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Affiliation(s)
- M Ochsner
- Ciba-Geigy Ltd., Physics Department, Basle, Switzerland
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Deadwyler G, Sima PD, Fu Y, Kanofsky JR. Singlet oxygen-mediated inactivation of acetylcholinesterase: a comparison of purified enzyme in solution and enzyme bound to K562 leukemia cells. Photochem Photobiol 1997; 65:884-94. [PMID: 9155262 DOI: 10.1111/j.1751-1097.1997.tb01939.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have compared the singlet oxygen-mediated inactivation of acetylcholinesterase (ACE) in solution with the inactivation of ACE on the surface of K562 leukemia cells. In solution, the actions of the singlet-oxygen quenchers, methionine, azide, disodium [N,N'-ethylenebis (5-sulfosalicylideneimminato)]nickelate(II) (Ni-chelate 1) and disodium [(N,N'-2,3-propionic acid)bis(5-sulfosal-icylideneimminato)] nickelate(II) (Ni-chelate 2) could be explained quantitatively by assuming their only mechanism of action was to quench singlet oxygen. The singlet oxygen quenchers, azide, Ni-chelate 1 and Ni-chelate 2, caused smaller inhibitions in the rate of singlet oxygen-mediated inactivation of ACE on K562 cells than ACE in solution. The effects of these quenchers and of deuterium oxide were interpreted using a mathematical model of singlet-oxygen quenching and diffusion to estimate the lifetime of singlet oxygen near the cell surface. The azide quenching data and the deuterium-oxide data gave lifetimes of 0.9 +/- 0.2 microsecond and 0.45 +/- 0.15 microsecond, respectively. The increases in ACE inactivation lifetime caused by the nickel chelates were anomalously large. The unexpectedly large quenching due to the nickel chelates may have been due to a nonuniform distribution of the chelates in the cytoplasm with a large concentration of the chelate near the cell membrane.
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Affiliation(s)
- G Deadwyler
- Hines Veterans Affairs Hospital, IL 60141, USA
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Shimizu O, Watanabe J, Imakubo K, Naito S. Formation of Singlet Oxygen Photosensitized by Aromatic Amino Acids in Aqueous Solutions. CHEM LETT 1997. [DOI: 10.1246/cl.1997.203] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Kochevar IE, Lambert CR, Lynch MC, Tedesco AC. Comparison of photosensitized plasma membrane damage caused by singlet oxygen and free radicals. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1280:223-30. [PMID: 8639697 DOI: 10.1016/0005-2736(95)00297-9] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The efficiency and selectivity of photosensitized damage to membrane functions may be influenced strongly by the identity of the initial reactive species formed by the photosensitizer. To test this possibility, a photosensitizer, rose bengal (RB), was used that resides in the plasma membrane and which generates singlet molecular oxygen (1O2*) upon excitation with visible light, and radicals plus 1O2* upon excitation with UV radiation. With this approach, 1O2* and radicals are formed at the same locations in the plasma membrane. The response of three plasma membrane functions, namely, proline transport, membrane potential, and membrane impermeability to charged dye molecules, was assessed. The efficiencies of the responses in the presence and absence of oxygen were compared per photon absorbed by RB at two wavelengths, 355 nm (UV excitation) and 532 nm (visible excitation). The efficiency of oxygen removal before irradiation was assessed by measuring the RB triplet lifetime. The three membrane functions were inhibited more efficiently at 355 nm than at 532 nm in the presence of oxygen indicating that the radicals are more effective at initiating damage to membrane components than 1O2*. The ratio of photosensitized effects at the two wavelengths in the presence of oxygen was the same for two membrane functions but not for the third suggesting that 1O2* and radicals initiate a common mechanistic pathway for damage to some membrane functions but not to others. Removing oxygen reduced the efficiency of 355 nm-induced photosensitization by factors of 1.4 to 7. The sensitivity of the three membrane functions to 1O2*-initiated damage varied over a factor of 50 whereas radical initiated damage only varied by a factor of 15. In summary, these results indicate that radicals and 1O2* formed at the same locations in the plasma membrane vary in their efficiency and specificity for membrane damage but may, in some cases, operate by a common secondary damage mechanism in the presence of oxygen.
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Affiliation(s)
- I E Kochevar
- Wellman Laboratories of Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA.
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Fu Y, Sima PD, Kanofsky JR. Singlet-Oxygen Generation from Liposomes: A Comparison of 6β-Cholesterol Hydroperoxide Formation with Predictions from a One-Dimensional Model of Singlet-Oxygen Diffusion and Quenching. Photochem Photobiol 1996. [DOI: 10.1111/j.1751-1097.1996.tb03071.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Fu Y, Kanofsky JR. SINGLET OXYGEN GENERATION FROM LIPOSOMES: A COMPARISON OF TIME-RESOLVED 1270 NM EMISSION WITH SINGLET-OXYGEN KINETICS CALCULATED FROM A ONE DIMENSIONAL MODEL OF SINGLET-OXYGEN DIFFUSION and QUENCHING. Photochem Photobiol 1995. [DOI: 10.1111/j.1751-1097.1995.tb08718.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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