1
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Kukulage DSK, Samarasinghe KTG, Matarage Don NNJ, Shivamadhu MC, Shishikura K, Schiff W, Mashhadi Ramezani F, Padmavathi R, Matthews ML, Ahn YH. Protein phosphatase PP2Cα S-glutathionylation regulates cell migration. J Biol Chem 2024:107784. [PMID: 39303918 DOI: 10.1016/j.jbc.2024.107784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Revised: 08/07/2024] [Accepted: 08/29/2024] [Indexed: 09/22/2024] Open
Abstract
Redox signaling is a fundamental mechanism that controls all major biological processes partly via protein cysteine oxidations, including S-glutathionylation. Despite over 2,000 cysteines identified to form S-glutathionylation in databases, the identification of redox cysteines functionally linked to a biological process of interest remains challenging. Here, we demonstrate a strategy combining glutathionylation proteomic database, bioinformatics, and biological screening, which resulted in the identification of S-glutathionylated proteins, including PP2Cα, as redox players of cell migration. We showed that PP2Cα, a prototypical magnesium-dependent serine/threonine phosphatase, is susceptible to S-glutathionylation selectively at non-conserved C314. PP2Cα glutathionylation causes increased migration and invasion of breast cancer cell lines in oxidative stress or upon hydrogen peroxide production. Mechanistically, PP2Cα glutathionylation modulates its protein-protein interactions, activating c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) pathways to elevate migration and invasion. In addition, PP2Cα glutathionylation occurs in response to epidermal-growth factor, supporting a serine/threonine phosphatase PP2Cα as a new redox player in growth factor signal transduction.
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Affiliation(s)
| | | | | | | | - Kyosuke Shishikura
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - William Schiff
- Department of Chemistry, Drexel University, Philadelphia, PA 19104, USA
| | | | | | - Megan L Matthews
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Young-Hoon Ahn
- Department of Chemistry, Drexel University, Philadelphia, PA 19104, USA.
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2
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Assessing the potential role of copper and cobalt in stimulating angiogenesis for tissue regeneration. PLoS One 2021; 16:e0259125. [PMID: 34705886 PMCID: PMC8550415 DOI: 10.1371/journal.pone.0259125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/12/2021] [Indexed: 11/19/2022] Open
Abstract
The use of copper (Cu2+) and cobalt (Co2+) has been described to stimulate blood vessel formation, a key process for the success of tissue regeneration. However, understanding how different concentrations of these ions affect cellular response is important to design scaffolds for their delivery to better fine tune the angiogenic response. On the one hand, gene expression analysis and the assessment of tubular formation structures with human umbilical vein endothelial cells (HUVEC) revealed that high concentrations (10μM) of Cu2+ in early times and lower concentrations (0.1 and 1μM) at later times (day 7) enhanced angiogenic response. On the other hand, higher concentrations (25μM) of Co2+ during all time course increased the angiogenic gene expression and 0.5, 5 and 25μM enhanced the ability to form tubular structures. To further explore synergistic effects combining both ions, the non-toxic concentrations were used simultaneously, although results showed an increased cell toxicity and no improvement of angiogenic response. These results provide useful information for the design of Cu2+ or Co2+ delivery scaffolds in order to release the appropriate concentration during time course for blood vessel stimulation.
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3
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FLIM-Based Intracellular and Extracellular pH Measurements Using Genetically Encoded pH Sensor. BIOSENSORS-BASEL 2021; 11:bios11090340. [PMID: 34562930 PMCID: PMC8468847 DOI: 10.3390/bios11090340] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/07/2021] [Accepted: 09/10/2021] [Indexed: 02/04/2023]
Abstract
The determination of pH in live cells and tissues is of high importance in physiology and cell biology. In this report, we outline the process of the creation of SypHerExtra, a genetically encoded fluorescent sensor that is capable of measuring extracellular media pH in a mildly alkaline range. SypHerExtra is a protein created by fusing the previously described pH sensor SypHer3s with the neurexin transmembrane domain that targets its expression to the cytoplasmic membrane. We showed that with excitation at 445 nm, the fluorescence lifetime of both SypHer3s and SypHerExtra strongly depend on pH. Using FLIM microscopy in live eukaryotic cells, we demonstrated that SypHerExtra can be successfully used to determine extracellular pH, while SypHer3s can be applied to measure intracellular pH. Thus, these two sensors are suitable for quantitative measurements using the FLIM method, to determine intracellular and extracellular pH in a range from pH 7.5 to 9.5 in different biological systems.
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4
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Su J, Zhang S, Wang C, Li M, Wang J, Su F, wang Z. MACA Fast and Efficient Method for Detecting H 2O 2 by a Dual-Locked Model Chemosensor. ACS OMEGA 2021; 6:14819-14823. [PMID: 34151063 PMCID: PMC8209827 DOI: 10.1021/acsomega.1c00384] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 05/17/2021] [Indexed: 05/05/2023]
Abstract
A pentafluorobenzene-containing fluorescent probe GW-1 was designed and synthesized for monitoring hydrogen peroxide. The probe's fluorescence was activated by a dual-locked model system that consists of a spiro location and a target analyte, which avoids the "alkalizing effect." The smart GW-1 exhibited high selectivity toward hydrogen peroxide over other reactive oxygen species (ROS) by a dual-controlled molecular switch. These features are favorable for H2O2 sensing and pH changes in bioanalytical and biomedical applications.
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Affiliation(s)
- Jing Su
- Department of Chemistry, Changzhi University, Changzhi 046011, P. R. China
| | - Shuping Zhang
- Department of Chemistry, Changzhi University, Changzhi 046011, P. R. China
| | - Cairong Wang
- Department of Chemistry, Changzhi University, Changzhi 046011, P. R. China
| | - Min Li
- Department of Chemistry, Changzhi University, Changzhi 046011, P. R. China
| | - Jiajia Wang
- Department of Chemistry, Changzhi University, Changzhi 046011, P. R. China
| | - Feng Su
- Department of Chemistry, Changzhi University, Changzhi 046011, P. R. China
| | - Zhijun wang
- Department of Chemistry, Changzhi University, Changzhi 046011, P. R. China
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5
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Lee S, Kim HS, Kim MJ, Min KY, Choi WS, You JS. Glutamine metabolite α-ketoglutarate acts as an epigenetic co-factor to interfere with osteoclast differentiation. Bone 2021; 145:115836. [PMID: 33383217 DOI: 10.1016/j.bone.2020.115836] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/19/2020] [Accepted: 12/22/2020] [Indexed: 01/23/2023]
Abstract
Osteoclasts (OCs) have been well-known involved in the exacerbation of bone-related diseases. However, the role of metabolites on osteoclastogenesis has not been well characterized. Herein, we found osteoclastogenesis was negatively regulated by α-ketoglutarate (αKG) in vitro and in vivo (C57BL/6 mouse). Kinetic transcriptome analysis revealed the upregulation of solute carrier family 7 member 11 (Slc7a11), a subunit of the cysteine/glutamate antiporter, as well as the downregulation of typical OC maker genes through αKG treatment. Given that Slc7a11 could control ROS level through glutathione import, we measured intracellular ROS, then RANKL-induced ROS production was inhibited by αKG. Notably, we highlight that αKG plays an epigenetic co-factor at the Slc7a11 promoter by demethylating repressive histone H3K9 methylation and simultaneously increasing the nuclear factor erythroid 2-related factor (Nrf2) binding, a critical transcription factor through chromatin immunoprecipitation (ChIP) analysis. Together, we suggested that αKG could be a therapeutic strategy for OC activated diseases.
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Affiliation(s)
- Sangyong Lee
- School of Medicine, Konkuk University, Seoul, South Korea
| | - Hyuk Soon Kim
- Department of Biomedical Sciences, College of Natural Science, Dong-A University, Busan, South Korea; Department of Health Sciences, The Graduate School of Dong-A University, Busan, South Korea
| | - Myoung Jun Kim
- School of Medicine, Konkuk University, Seoul, South Korea
| | - Keun Young Min
- School of Medicine, Konkuk University, Seoul, South Korea
| | - Wahn Soo Choi
- School of Medicine, Konkuk University, Seoul, South Korea; Research Institute of Medical Science, KU Open Innovation Center, Konkuk University, Seoul, South Korea
| | - Jueng Soo You
- School of Medicine, Konkuk University, Seoul, South Korea; Research Institute of Medical Science, KU Open Innovation Center, Konkuk University, Seoul, South Korea.
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6
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Collins JA, Kapustina M, Bolduc JA, Pike JFW, Diekman BO, Mix K, Chubinskaya S, Eroglu E, Michel T, Poole LB, Furdui CM, Loeser RF. Sirtuin 6 (SIRT6) regulates redox homeostasis and signaling events in human articular chondrocytes. Free Radic Biol Med 2021; 166:90-103. [PMID: 33600943 PMCID: PMC8009856 DOI: 10.1016/j.freeradbiomed.2021.01.054] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/29/2021] [Accepted: 01/31/2021] [Indexed: 12/30/2022]
Abstract
The nuclear localized protein deacetylase, SIRT6, has been identified as a crucial regulator of biological processes that drive aging. Among these processes, SIRT6 can promote resistance to oxidative stress conditions, but the precise mechanisms remain unclear. The objectives of this study were to examine the regulation of SIRT6 activity by age and oxidative stress and define the role of SIRT6 in maintaining redox homeostasis in articular chondrocytes. Although SIRT6 levels did not change with age, SIRT6 activity was significantly reduced in chondrocytes isolated from older adults. Using dimedone-based chemical probes that detect oxidized cysteines, we identified that SIRT6 is oxidized in response to oxidative stress conditions, an effect that was associated with reduced SIRT6 activity. Enhancement of SIRT6 activity through adenoviral SIRT6 overexpression specifically increased the basal levels of two antioxidant proteins, peroxiredoxin 1 (Prx1) and sulfiredoxin (Srx) and decreased the levels of an inhibitor of antioxidant activity, thioredoxin interacting protein (TXNIP). Conversely, in chondrocytes derived from mice with cartilage specific Sirt6 knockout, Sirt6 loss decreased Prx1 levels and increased TXNIP levels. SIRT6 overexpression decreased nuclear-generated H2O2 levels and oxidative stress-induced accumulation of nuclear phosphorylated p65. Our data demonstrate that SIRT6 activity is altered with age and oxidative stress conditions associated with aging. SIRT6 contributes to chondrocyte redox homeostasis by regulating specific members of the Prx catalytic cycle. Targeted therapies aimed at preventing the age-related decline in SIRT6 activity may represent a novel strategy to maintain redox balance in joint tissues and decrease catabolic signaling events implicated in osteoarthritis (OA).
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Affiliation(s)
- John A Collins
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA.
| | - Maryna Kapustina
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jesalyn A Bolduc
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Brussels Center for Redox Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussel, Belgium
| | - James F W Pike
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Brian O Diekman
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC, USA
| | - Kimberlee Mix
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Biological Sciences, Loyola University New Orleans, New Orleans, LA, USA
| | - Susan Chubinskaya
- Department of Pediatrics, Rush University Medical Center, Chicago, IL, USA
| | - Emrah Eroglu
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston MA, USA; Sabanci University, Faculty of Engineering and Natural Sciences, Genetics and Bioengineering Program, Nanotechnology Research and Application Center, Istanbul, Turkey
| | - Thomas Michel
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston MA, USA
| | - Leslie B Poole
- Department of Biochemistry, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Cristina M Furdui
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Richard F Loeser
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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7
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Stein KT, Moon SJ, Nguyen AN, Sikes HD. Kinetic modeling of H2O2 dynamics in the mitochondria of HeLa cells. PLoS Comput Biol 2020; 16:e1008202. [PMID: 32925922 PMCID: PMC7515204 DOI: 10.1371/journal.pcbi.1008202] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 09/24/2020] [Accepted: 07/28/2020] [Indexed: 12/15/2022] Open
Abstract
Hydrogen peroxide (H2O2) promotes a range of phenotypes depending on its intracellular concentration and dosing kinetics, including cell death. While this qualitative relationship has been well established, the quantitative and mechanistic aspects of H2O2 signaling are still being elucidated. Mitochondria, a putative source of intracellular H2O2, have recently been demonstrated to be particularly vulnerable to localized H2O2 perturbations, eliciting a dramatic cell death response in comparison to similar cytosolic perturbations. We sought to improve our dynamic and mechanistic understanding of the mitochondrial H2O2 reaction network in HeLa cells by creating a kinetic model of this system and using it to explore basal and perturbed conditions. The model uses the most current quantitative proteomic and kinetic data available to predict reaction rates and steady-state concentrations of H2O2 and its reaction partners within individual mitochondria. Time scales ranging from milliseconds to one hour were simulated. We predict that basal, steady-state mitochondrial H2O2 will be in the low nM range (2-4 nM) and will be inversely dependent on the total pool of peroxiredoxin-3 (Prx3). Neglecting efflux of H2O2 to the cytosol, the mitochondrial reaction network is expected to control perturbations well up to H2O2 generation rates ~50 μM/s (0.25 nmol/mg-protein/s), above which point the Prx3 system would be expected to collapse. Comparison of these results with redox Western blots of Prx3 and Prx2 oxidation states demonstrated reasonable trend agreement at short times (≤ 15 min) for a range of experimentally perturbed H2O2 generation rates. At longer times, substantial efflux of H2O2 from the mitochondria to the cytosol was evidenced by peroxiredoxin-2 (Prx2) oxidation, and Prx3 collapse was not observed. A refined model using Monte Carlo parameter sampling was used to explore rates of H2O2 efflux that could reconcile model predictions of Prx3 oxidation states with the experimental observations.
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Affiliation(s)
- Kassi T. Stein
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States of America
| | - Sun Jin Moon
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States of America
| | - Athena N. Nguyen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States of America
| | - Hadley D. Sikes
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States of America
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8
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Stein KT, Moon SJ, Sikes HD. Mitochondrial H 2O 2 Generation Using a Tunable Chemogenetic Tool To Perturb Redox Homeostasis in Human Cells and Induce Cell Death. ACS Synth Biol 2018; 7:2037-2044. [PMID: 30138563 DOI: 10.1021/acssynbio.8b00174] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Among reactive oxygen species (ROS), H2O2 alone acts as a signaling molecule that promotes diverse phenotypes depending on the intracellular concentration. Mitochondria have been suggested as both sources and sinks of cellular H2O2, and mitochondrial dysfunction has been implicated in diseases such as cancer. A genetically encoded H2O2 generator, d-amino acid oxidase (DAAO), was targeted to the mitochondria of human cells, and its utility in investigating cellular response to a range of H2O2 doses over time was assessed. Organelle-specific peroxiredoxin dimerization and protein S-glutathionylation were measured as indicators of increased H2O2 flux due to the activity of DAAO. Cell death was observed in a concentration- and time-dependent manner, and protein oxidation shifted in localization as the dose increased. This work presents the first systematic study of H2O2-specific perturbation of mitochondria in human cells, and it reveals a marked sensitivity of this organelle to increases in H2O2 in comparison with prior studies that targeted the cytosol.
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Affiliation(s)
- Kassi T. Stein
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Sun Jin Moon
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Hadley D. Sikes
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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9
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O'Sullivan SA, Velasco-Estevez M, Dev KK. Demyelination induced by oxidative stress is regulated by sphingosine 1-phosphate receptors. Glia 2017; 65:1119-1136. [PMID: 28375547 DOI: 10.1002/glia.23148] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 03/02/2017] [Accepted: 03/20/2017] [Indexed: 01/14/2023]
Abstract
Oxidative stress is a pathological condition defined as an imbalance between production and removal of reactive oxygen species. This process causes structural cell damage, disrupts DNA repair and induces mitochondrial dysfunction. Many in vitro studies have used direct bolus application of H2 O2 to investigate the role of oxidative stress in cell culture. In this study, using mouse organotypic cerebellar slice cultures, the effects of H2 O2 -induced oxidative stress on myelination state were examined, using bolus concentrations of H2 O2 (0.1-1 mM) and low-continuous H2 O2 (∼20 μM) generated from glucose oxidase and catalase (GOX-CAT). Using these models, the potential therapeutic effects of pFTY720, an oral therapy used in multiple sclerosis, was also examined. We found bolus treatment of H2 O2 (0.5 mM) and, for the first time, low-continuous H2 O2 (GOX-CAT) to induce demyelination in organotypic slices. Both bolus H2 O2 and GOX-CAT treatments significantly decreased vimentin expression in these slice cultures as well as increased cell death in isolated astrocyte cultures. Importantly, pre-treatment with pFTY720 significantly attenuated both bolus H2 O2 and GOX-CAT-induced demyelination and the GOX-CAT-induced decrease in vimentin in cerebellar slices, without altering levels of the proinflammatory cytokines such as IL-6 and CX3CL1. We also observed increased SMI-32 immunoreactivity in the white matter tract induced by GOX-CAT indicating axonal damage, which was remarkably attenuated by pFTY720. Taken together, this data establishes a novel GOX-CAT model of demyelination and demonstrates that pFTY720 can act independently of inflammatory cytokines to attenuate decreases in vimentin, as well as axonal damage and demyelination induced by oxidative stress.
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Affiliation(s)
- Sinead A O'Sullivan
- Drug Development, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | | | - Kumlesh K Dev
- Drug Development, School of Medicine, Trinity College Dublin, Dublin, Ireland
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10
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Long MJC, Poganik JR, Ghosh S, Aye Y. Subcellular Redox Targeting: Bridging in Vitro and in Vivo Chemical Biology. ACS Chem Biol 2017; 12:586-600. [PMID: 28068059 DOI: 10.1021/acschembio.6b01148] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Networks of redox sensor proteins within discrete microdomains regulate the flow of redox signaling. Yet, the inherent reactivity of redox signals complicates the study of specific redox events and pathways by traditional methods. Herein, we review designer chemistries capable of measuring flux and/or mimicking subcellular redox signaling at the cellular and organismal level. Such efforts have begun to decipher the logic underlying organelle-, site-, and target-specific redox signaling in vitro and in vivo. These data highlight chemical biology as a perfect gateway to interrogate how nature choreographs subcellular redox chemistry to drive precision redox biology.
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Affiliation(s)
- Marcus J. C. Long
- Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Jesse R. Poganik
- Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Souradyuti Ghosh
- Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Yimon Aye
- Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14850, United States
- Department
of Biochemistry, Weill Cornell Medicine, New York, New York 10065, United States
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11
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Huang BK, Stein KT, Sikes HD. Modulating and Measuring Intracellular H 2O 2 Using Genetically Encoded Tools to Study Its Toxicity to Human Cells. ACS Synth Biol 2016; 5:1389-1395. [PMID: 27428287 DOI: 10.1021/acssynbio.6b00120] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Reactive oxygen species (ROS) such as H2O2 play paradoxical roles in mammalian physiology. It is hypothesized that low, baseline levels of H2O2 are necessary for growth and differentiation, while increased intracellular H2O2 concentrations are associated with pathological phenotypes and genetic instability, eventually reaching a toxic threshold that causes cell death. However, the quantities of intracellular H2O2 that lead to these different responses remain an unanswered question in the field. To address this question, we used genetically encoded constructs that both generate and quantify H2O2 in a dose-response study of H2O2-mediated toxicity. We found that, rather than a simple concentration-response relationship, a combination of intracellular concentration and the cumulative metric of H2O2 concentration multiplied by time (i.e., the area under the curve) determined the occurrence and level of cell death. Establishing the quantitative relationship between H2O2 and cell toxicity promotes a deeper understanding of the intracellular effects of H2O2 specifically as an individual reactive oxygen species, and it contributes to an understanding of its role in various redox-related diseases.
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Affiliation(s)
- Beijing K. Huang
- Department
of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Kassi T. Stein
- Department
of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Hadley D. Sikes
- Department
of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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12
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Lim JB, Langford TF, Huang BK, Deen WM, Sikes HD. A reaction-diffusion model of cytosolic hydrogen peroxide. Free Radic Biol Med 2016; 90:85-90. [PMID: 26561774 DOI: 10.1016/j.freeradbiomed.2015.11.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 11/03/2015] [Accepted: 11/05/2015] [Indexed: 11/30/2022]
Abstract
As a signaling molecule in mammalian cells, hydrogen peroxide (H2O2) determines the thiol/disulfide oxidation state of several key proteins in the cytosol. Localization is a key concept in redox signaling; the concentrations of signaling molecules within the cell are expected to vary in time and in space in manner that is essential for function. However, as a simplification, all theoretical studies of intracellular hydrogen peroxide and many experimental studies to date have treated the cytosol as a well-mixed compartment. In this work, we incorporate our previously reported reduced kinetic model of the network of reactions that metabolize hydrogen peroxide in the cytosol into a model that explicitly treats diffusion along with reaction. We modeled a bolus addition experiment, solved the model analytically, and used the resulting equations to quantify the spatiotemporal variations in intracellular H2O2 that result from this kind of perturbation to the extracellular H2O2 concentration. We predict that micromolar bolus additions of H2O2 to suspensions of HeLa cells (0.8 × 10(9)cells/l) result in increases in the intracellular concentration that are localized near the membrane. These findings challenge the assumption that intracellular concentrations of H2O2 are increased uniformly throughout the cell during bolus addition experiments and provide a theoretical basis for differing phenotypic responses of cells to intracellular versus extracellular perturbations to H2O2 levels.
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Affiliation(s)
- Joseph B Lim
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Troy F Langford
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Beijing K Huang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - William M Deen
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Hadley D Sikes
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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13
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Lim JB, Huang BK, Deen WM, Sikes HD. Analysis of the lifetime and spatial localization of hydrogen peroxide generated in the cytosol using a reduced kinetic model. Free Radic Biol Med 2015; 89:47-53. [PMID: 26169725 DOI: 10.1016/j.freeradbiomed.2015.07.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 06/30/2015] [Accepted: 07/08/2015] [Indexed: 01/12/2023]
Abstract
Hydrogen peroxide (H2O2) acts as a signaling molecule via its reactions with particular cysteine residues of certain proteins. Determining the roles of direct oxidation by H2O2 versus disulfide exchange reactions (i.e. relay reactions) between oxidized and reduced proteins of different identities is a current focus. Here, we use kinetic modeling to estimate the spatial and temporal localization of H2O2 and its most likely oxidation targets during a sudden increase in H2O2 above the basal level in the cytosol. We updated a previous redox kinetic model with recently measured parameters for HeLa cells and used the model to estimate the length and time scales of H2O2 diffusion through the cytosol before it is consumed by reaction. These estimates were on the order of one micron and one millisecond, respectively. We found oxidation of peroxiredoxin by H2O2 to be the dominant reaction in the network and that the overall concentration of reduced peroxiredoxin is not significantly affected by physiological increases in intracellular H2O2 concentration. We used this information to reduce the model from 22 parameters and reactions and 21 species to a single analytical equation with only one dependent variable, i.e. the concentration of H2O2, and reproduced results from the complete model. The reduced kinetic model will facilitate future efforts to progress beyond estimates and precisely quantify how reactions and diffusion jointly influence the distribution of H2O2 within cells.
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Affiliation(s)
- Joseph B Lim
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Beijing K Huang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - William M Deen
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hadley D Sikes
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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