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Yago H, Homma J, Sekine H, Higashi Y, Sakurai H, Shimizu T. The bioengineering of perfusable endocrine tissue with anastomosable blood vessels. Biofabrication 2023; 15:045010. [PMID: 37487489 DOI: 10.1088/1758-5090/ace9fc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 07/24/2023] [Indexed: 07/26/2023]
Abstract
Organ transplantation is a definitive treatment for endocrine disorders, but donor shortages limit the use of this technique. The development of regenerative therapies would revolutionize the treatment of endocrine disorders. As is the case for harvested organs, the ideal bioengineered graft would comprise vascularized endocrine tissue, contain blood vessels that could be anastomosed to host vessels, have stable blood flow, and be suitable for transplantation into various sites. Here, we describe a transplantable endocrine tissue graft that was fabricated byex vivoperfusion of tricultured cell sheets (isletβ-cells, vascular endothelial cells (vECs), and mesenchymal stem cells (MSCs)) on a vascularized tissue flap ofin vivoorigin. The present study has three key findings. First, mild hypothermic conditions enhanced the success ofex vivoperfusion culture. Specifically, graft construction failed at 37 °C but succeeded at 32 °C (mild hypothermia), and endocrine tissue fabricated under mild hypothermia contained aggregations of isletβ-cells surrounded by dense vascular networks. Second, the construction of transplantable endocrine tissue byex vivoperfusion culture was better achieved using a vascular flap (VF) than a muscle flap. Third, the endocrine tissue construct generated using a VF could be transplanted into the rat by anastomosis of the graft artery and vein to host blood vessels, and the graft secreted insulin into the host's circulatory system for at least two weeks after transplantation. Endocrine tissues bioengineered using these techniques potentially could be used as novel endocrine therapies.
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Affiliation(s)
- Hiroki Yago
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan
- Department of Plastic and Reconstructive Surgery, Tokyo Women's Medical University, Tokyo, Japan
| | - Jun Homma
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan
| | - Hidekazu Sekine
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan
| | - Yuhei Higashi
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan
- Tokaihit Co., Ltd, Shizuoka, Japan
| | - Hiroyuki Sakurai
- Department of Plastic and Reconstructive Surgery, Tokyo Women's Medical University, Tokyo, Japan
| | - Tatsuya Shimizu
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan
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Zanetti C, Gaspar RDL, Zhdanov AV, Maguire NM, Joyce SA, Collins SG, Maguire AR, Papkovsky DB. Heterosubstituted Derivatives of PtPFPP for O 2 Sensing and Cell Analysis: Structure–Activity Relationships. Bioconjug Chem 2022; 33:2161-2169. [DOI: 10.1021/acs.bioconjchem.2c00400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chiara Zanetti
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 XF62, Ireland
| | | | - Alexander V. Zhdanov
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 XF62, Ireland
| | - Nuala M. Maguire
- School of Chemistry, University College Cork, Cork T12 YN60, Ireland
| | - Susan A. Joyce
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 XF62, Ireland
| | - Stuart G. Collins
- School of Chemistry, University College Cork, Cork T12 YN60, Ireland
| | - Anita R. Maguire
- School of Chemistry and School of Pharmacy, University College Cork, Cork T12 YN60, Ireland
| | - Dmitri B. Papkovsky
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 XF62, Ireland
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Benáková Š, Holendová B, Plecitá-Hlavatá L. Redox Homeostasis in Pancreatic β-Cells: From Development to Failure. Antioxidants (Basel) 2021; 10:antiox10040526. [PMID: 33801681 PMCID: PMC8065646 DOI: 10.3390/antiox10040526] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 12/16/2022] Open
Abstract
Redox status is a key determinant in the fate of β-cell. These cells are not primarily detoxifying and thus do not possess extensive antioxidant defense machinery. However, they show a wide range of redox regulating proteins, such as peroxiredoxins, thioredoxins or thioredoxin reductases, etc., being functionally compartmentalized within the cells. They keep fragile redox homeostasis and serve as messengers and amplifiers of redox signaling. β-cells require proper redox signaling already in cell ontogenesis during the development of mature β-cells from their progenitors. We bring details about redox-regulated signaling pathways and transcription factors being essential for proper differentiation and maturation of functional β-cells and their proliferation and insulin expression/maturation. We briefly highlight the targets of redox signaling in the insulin secretory pathway and focus more on possible targets of extracellular redox signaling through secreted thioredoxin1 and thioredoxin reductase1. Tuned redox homeostasis can switch upon chronic pathological insults towards the dysfunction of β-cells and to glucose intolerance. These are characteristics of type 2 diabetes, which is often linked to chronic nutritional overload being nowadays a pandemic feature of lifestyle. Overcharged β-cell metabolism causes pressure on proteostasis in the endoplasmic reticulum, mainly due to increased demand on insulin synthesis, which establishes unfolded protein response and insulin misfolding along with excessive hydrogen peroxide production. This together with redox dysbalance in cytoplasm and mitochondria due to enhanced nutritional pressure impact β-cell redox homeostasis and establish prooxidative metabolism. This can further affect β-cell communication in pancreatic islets through gap junctions. In parallel, peripheral tissues losing insulin sensitivity and overall impairment of glucose tolerance and gut microbiota establish local proinflammatory signaling and later systemic metainflammation, i.e., low chronic inflammation prooxidative properties, which target β-cells leading to their dedifferentiation, dysfunction and eventually cell death.
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Affiliation(s)
- Štěpánka Benáková
- Department of Mitochondrial Physiology, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic; (Š.B.); (B.H.)
- First Faculty of Medicine, Charles University, Katerinska 1660/32, 121 08 Prague, Czech Republic
| | - Blanka Holendová
- Department of Mitochondrial Physiology, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic; (Š.B.); (B.H.)
| | - Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic; (Š.B.); (B.H.)
- Department of Mitochondrial Physiology, Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic
- Correspondence: ; Tel.: +420-296-442-285
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Horne SJ, Vasquez JM, Guo Y, Ly V, Piret SE, Leonardo AR, Ling J, Revelo MP, Bogenhagen D, Yang VW, He JC, Mallipattu SK. Podocyte-Specific Loss of Krüppel-Like Factor 6 Increases Mitochondrial Injury in Diabetic Kidney Disease. Diabetes 2018; 67:2420-2433. [PMID: 30115650 PMCID: PMC6198342 DOI: 10.2337/db17-0958] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 08/03/2018] [Indexed: 12/25/2022]
Abstract
Mitochondrial injury is uniformly observed in several murine models as well as in individuals with diabetic kidney disease (DKD). Although emerging evidence has highlighted the role of key transcriptional regulators in mitochondrial biogenesis, little is known about the regulation of mitochondrial cytochrome c oxidase assembly in the podocyte under diabetic conditions. We recently reported a critical role of the zinc finger Krüppel-like factor 6 (KLF6) in maintaining mitochondrial function and preventing apoptosis in a proteinuric murine model. In this study, we report that podocyte-specific knockdown of Klf6 increased the susceptibility to streptozotocin-induced DKD in the resistant C57BL/6 mouse strain. We observed that the loss of KLF6 in podocytes reduced the expression of synthesis of cytochrome c oxidase 2 with resultant increased mitochondrial injury, leading to activation of the intrinsic apoptotic pathway under diabetic conditions. Conversely, mitochondrial injury and apoptosis were significantly attenuated with overexpression of KLF6 in cultured human podocytes under hyperglycemic conditions. Finally, we observed a significant reduction in glomerular and podocyte-specific expression of KLF6 in human kidney biopsies with progression of DKD. Collectively, these data suggest that podocyte-specific KLF6 is critical to preventing mitochondrial injury and apoptosis under diabetic conditions.
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Affiliation(s)
- Sylvia J Horne
- Division of Nephrology, Department of Medicine, Stony Brook University, Stony Brook, NY
| | - Jessica M Vasquez
- Division of Nephrology, Department of Medicine, Stony Brook University, Stony Brook, NY
| | - Yiqing Guo
- Division of Nephrology, Department of Medicine, Stony Brook University, Stony Brook, NY
| | - Victoria Ly
- Division of Nephrology, Department of Medicine, Stony Brook University, Stony Brook, NY
| | - Sian E Piret
- Division of Nephrology, Department of Medicine, Stony Brook University, Stony Brook, NY
| | - Alexandra R Leonardo
- Division of Nephrology, Department of Medicine, Stony Brook University, Stony Brook, NY
| | - Jason Ling
- Division of Nephrology, Department of Medicine, Stony Brook University, Stony Brook, NY
| | - Monica P Revelo
- Department of Pathology, University of Utah, Salt Lake City, UT
| | - Daniel Bogenhagen
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY
| | - Vincent W Yang
- Division of Gastroenterology, Department of Medicine, Stony Brook University, Stony Brook, NY
| | - John C He
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY
- Renal Section, James J. Peters VA Medical Center, New York, NY
| | - Sandeep K Mallipattu
- Division of Nephrology, Department of Medicine, Stony Brook University, Stony Brook, NY
- Renal Section, Northport VA Medical Center, Northport, NY
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5
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Golubev A, Hanson AD, Gladyshev VN. A Tale of Two Concepts: Harmonizing the Free Radical and Antagonistic Pleiotropy Theories of Aging. Antioxid Redox Signal 2018; 29:1003-1017. [PMID: 28874059 PMCID: PMC6104246 DOI: 10.1089/ars.2017.7105] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Revised: 08/09/2017] [Accepted: 08/31/2017] [Indexed: 12/18/2022]
Abstract
SIGNIFICANCE The two foremost concepts of aging are the mechanistic free radical theory (FRT) of how we age and the evolutionary antagonistic pleiotropy theory (APT) of why we age. Both date from the late 1950s. The FRT holds that reactive oxygen species (ROS) are the principal contributors to the lifelong cumulative damage suffered by cells, whereas the APT is generally understood as positing that genes that are good for young organisms can take over a population even if they are bad for the old organisms. Recent Advances: Here, we provide a common ground for the two theories by showing how aging can result from the inherent chemical reactivity of many biomolecules, not just ROS, which imposes a fundamental constraint on biological evolution. Chemically reactive metabolites spontaneously modify slowly renewable macromolecules in a continuous way over time; the resulting buildup of damage wrought by the genes coding for enzymes that generate such small molecules eventually masquerades as late-acting pleiotropic effects. In aerobic organisms, ROS are major agents of this damage but they are far from alone. CRITICAL ISSUES Being related to two sides of the same phenomenon, these theories should be compatible. However, the interface between them is obscured by the FRT mistaking a subset of damaging processes for the whole, and the APT mistaking a cumulative quantitative process for a qualitative switch. FUTURE DIRECTIONS The manifestations of ROS-mediated cumulative chemical damage at the population level may include the often-observed negative correlation between fitness and the rate of its decline with increasing age, further linking FRT and APT. Antioxid. Redox Signal. 29, 1003-1017.
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Affiliation(s)
- Alexey Golubev
- Department of Carcinogenesis and Oncogerontology, Petrov Research Institute of Oncology, Saint Petersburg, Russia
| | - Andrew D. Hanson
- Horticultural Sciences Department, University of Florida, Gainesville, Florida
| | - Vadim N. Gladyshev
- Division of Genetics, Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow Russia
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Kanno Y, Ino K, Abe H, Sakamoto C, Onodera T, Inoue KY, Suda A, Kunikata R, Matsudaira M, Shiku H, Matsue T. Electrochemicolor Imaging Using an LSI-Based Device for Multiplexed Cell Assays. Anal Chem 2017; 89:12778-12786. [PMID: 29090905 DOI: 10.1021/acs.analchem.7b03042] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Multiplexed bioimaging systems have triggered the development of effective assays, contributing new biological information. Although electrochemical imaging is beneficial for quantitative analysis in real time, monitoring multiple cell functions is difficult. We have developed a novel electrochemical imaging system, herein, using a large-scale integration (LSI)-based amperometric device for detecting multiple biomolecules simultaneously. This system is designated as an electrochemicolor imaging system in which the current signals from two different types of biomolecules are depicted as a multicolor electrochemical image. The mode-selectable function of the 400-electrode device enables the imaging system and two different potentials can be independently applied to the selected electrodes. The imaging system is successfully applied for detecting multiple cell functions of the embryonic stem (ES) cell and the rat pheochromocytoma (PC12) cell aggregates. To the best of our knowledge, this is the first time that a real-time electrochemical mapping technique for multiple electroactive species, simultaneously, has been reported. The imaging system is a promising bioanalytical method for exploring complex biological phenomena.
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Affiliation(s)
- Yusuke Kanno
- Graduate School of Environmental Studies, Tohoku University , 6-6-11-604 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
| | - Kosuke Ino
- Graduate School of Engineering, Tohoku University , 6-6-11-406 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
| | - Hiroya Abe
- Graduate School of Environmental Studies, Tohoku University , 6-6-11-604 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
| | - Chika Sakamoto
- Graduate School of Environmental Studies, Tohoku University , 6-6-11-604 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
| | - Takehiro Onodera
- Graduate School of Engineering, Tohoku University , 6-6-11-406 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
| | - Kumi Y Inoue
- Graduate School of Environmental Studies, Tohoku University , 6-6-11-604 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
| | - Atsushi Suda
- Japan Aviation Electronics Industry, Ltd. , 1-1 Musashino 3-chome, Akishima-shi, Tokyo 196-8555, Japan
| | - Ryota Kunikata
- Japan Aviation Electronics Industry, Ltd. , 1-1 Musashino 3-chome, Akishima-shi, Tokyo 196-8555, Japan
| | - Masahki Matsudaira
- Micro System Integration Center, Tohoku University , 519-1176 Aramaki-aza Aoba, Aoba-ku, Sendai 980-0845, Japan
| | - Hitoshi Shiku
- Graduate School of Engineering, Tohoku University , 6-6-11-406 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
| | - Tomokazu Matsue
- Graduate School of Environmental Studies, Tohoku University , 6-6-11-604 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
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Papkovsky DB, Zhdanov AV. Phosphorescence based O 2 sensors - Essential tools for monitoring cell and tissue oxygenation and its impact on metabolism. Free Radic Biol Med 2016; 101:202-210. [PMID: 27789291 DOI: 10.1016/j.freeradbiomed.2016.09.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 09/13/2016] [Accepted: 09/22/2016] [Indexed: 12/27/2022]
Abstract
Oxygenation condition at the cellular level is a critical factor in tissue physiology and common pathophysiological states including cancer, metabolic disorders, ischemia-reperfusion injury and inflammation. O2 and ROS signalling and hypoxia research are rapidly growing areas spanning life and biomedical sciences, but still many current cell and tissue models and experimental set ups lack physiological relevance, particularly precise control of cellular O2. Quenched-phosphorescence O2 sensing enables implementation of such in situ control of cellular O2 and the creation of physiological conditions in respiring samples analysed in vitro. The advantages of optical O2 sensing are the non-invasive, contactless, real-time, quantitative monitoring of O2 concentration, which can be performed in the gas or liquid phase, macroscopically or microscopically, by point measurement or in imaging mode, with sub-cellular spatial resolution, in a flexible manner and with various cell and tissue models. Significantly, this same technology can also be used to probe the metabolism of cells and tissue under specific oxygenation conditions and their responses to changing conditions. Here we describe the range of available O2 sensing systems and tools, their analytical capabilities, uses in cell/tissue physiology and hypoxia research, and strategies for integration in routine experimental procedures.
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Affiliation(s)
- Dmitri B Papkovsky
- School of Biochemistry and Cell Biology, University College Cork, Cavanagh Pharmacy Building, College Road, Cork, Ireland.
| | - Alexander V Zhdanov
- School of Biochemistry and Cell Biology, University College Cork, Cavanagh Pharmacy Building, College Road, Cork, Ireland
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Zhdanov AV, Okkelman IA, Collins FW, Melgar S, Papkovsky DB. A novel effect of DMOG on cell metabolism: direct inhibition of mitochondrial function precedes HIF target gene expression. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1254-66. [DOI: 10.1016/j.bbabio.2015.06.016] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 06/11/2015] [Accepted: 06/30/2015] [Indexed: 12/17/2022]
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9
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Mallipattu SK, Horne SJ, D'Agati V, Narla G, Liu R, Frohman MA, Dickman K, Chen EY, Ma'ayan A, Bialkowska AB, Ghaleb AM, Nandan MO, Jain MK, Daehn I, Chuang PY, Yang VW, He JC. Krüppel-like factor 6 regulates mitochondrial function in the kidney. J Clin Invest 2015; 125:1347-61. [PMID: 25689250 DOI: 10.1172/jci77084] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 12/09/2014] [Indexed: 11/17/2022] Open
Abstract
Maintenance of mitochondrial structure and function is critical for preventing podocyte apoptosis and eventual glomerulosclerosis in the kidney; however, the transcription factors that regulate mitochondrial function in podocyte injury remain to be identified. Here, we identified Krüppel-like factor 6 (KLF6), a zinc finger domain transcription factor, as an essential regulator of mitochondrial function in podocyte apoptosis. We observed that podocyte-specific deletion of Klf6 increased the susceptibility of a resistant mouse strain to adriamycin-induced (ADR-induced) focal segmental glomerulosclerosis (FSGS). KLF6 expression was induced early in response to ADR in mice and cultured human podocytes, and prevented mitochondrial dysfunction and activation of intrinsic apoptotic pathways in these podocytes. Promoter analysis and chromatin immunoprecipitation studies revealed that putative KLF6 transcriptional binding sites are present in the promoter of the mitochondrial cytochrome c oxidase assembly gene (SCO2), which is critical for preventing cytochrome c release and activation of the intrinsic apoptotic pathway. Additionally, KLF6 expression was reduced in podocytes from HIV-1 transgenic mice as well as in renal biopsies from patients with HIV-associated nephropathy (HIVAN) and FSGS. Together, these findings indicate that KLF6-dependent regulation of the cytochrome c oxidase assembly gene is critical for maintaining mitochondrial function and preventing podocyte apoptosis.
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10
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Zhdanov AV, Waters AHC, Golubeva AV, Papkovsky DB. Differential contribution of key metabolic substrates and cellular oxygen in HIF signalling. Exp Cell Res 2014; 330:13-28. [PMID: 25447307 DOI: 10.1016/j.yexcr.2014.10.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 10/02/2014] [Accepted: 10/05/2014] [Indexed: 12/25/2022]
Abstract
Changes in availability and utilisation of O2 and metabolic substrates are common in ischemia and cancer. We examined effects of substrate deprivation on HIF signalling in PC12 cells exposed to different atmospheric O2. Upon 2-4h moderate hypoxia, HIF-α protein levels were dictated by the availability of glutamine and glucose, essential for deep cell deoxygenation and glycolytic ATP flux. Nuclear accumulation of HIF-1α dramatically decreased upon inhibition of glutaminolysis or glutamine deprivation. Elevation of HIF-2α levels was transcription-independent and associated with the activation of Akt and Erk1/2. Upon 2h anoxia, HIF-2α levels strongly correlated with cellular ATP, produced exclusively via glycolysis. Without glucose, HIF signalling was suppressed, giving way to other regulators of cell adaptation to energy crisis, e.g. AMPK. Consequently, viability of cells deprived of O2 and glucose decreased upon inhibition of AMPK with dorsomorphin. The capacity of cells to accumulate HIF-2α decreased after 24h glucose deprivation. This effect, associated with increased AMPKα phosphorylation, was sensitive to dorsomorphin. In chronically hypoxic cells, glutamine played no major role in HIF-2α accumulation, which became mainly glucose-dependent. Overall, the availability of O2 and metabolic substrates intricately regulates HIF signalling by affecting cell oxygenation, ATP levels and pathways involved in production of HIF-α.
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Affiliation(s)
- Alexander V Zhdanov
- School of Biochemistry and Cell Biology, University College Cork, Cavanagh Pharmacy Building, College Road, Cork, Ireland.
| | - Alicia H C Waters
- School of Biochemistry and Cell Biology, University College Cork, Cavanagh Pharmacy Building, College Road, Cork, Ireland
| | - Anna V Golubeva
- Alimentary Pharmabiotic Centre, University College Cork, Bioscience Institute, Western Road, Cork, Ireland
| | - Dmitri B Papkovsky
- School of Biochemistry and Cell Biology, University College Cork, Cavanagh Pharmacy Building, College Road, Cork, Ireland
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Zhdanov AV, Dmitriev RI, Hynes J, Papkovsky DB. Kinetic Analysis of Local Oxygenation and Respiratory Responses of Mammalian Cells Using Intracellular Oxygen-Sensitive Probes and Time-Resolved Fluorometry. Methods Enzymol 2014; 542:183-207. [DOI: 10.1016/b978-0-12-416618-9.00010-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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12
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Zhdanov AV, Waters AHC, Golubeva AV, Dmitriev RI, Papkovsky DB. Availability of the key metabolic substrates dictates the respiratory response of cancer cells to the mitochondrial uncoupling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:51-62. [PMID: 23891695 DOI: 10.1016/j.bbabio.2013.07.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 07/16/2013] [Accepted: 07/17/2013] [Indexed: 12/12/2022]
Abstract
Active glycolysis and glutaminolysis provide bioenergetic stability of cancer cells in physiological conditions. Under hypoxia, metabolic and mitochondrial disorders, or pharmacological treatment, a deficit of key metabolic substrates may become life-threatening to cancer cells. We analysed the effects of mitochondrial uncoupling by FCCP on the respiration of cells fed by different combinations of Glc, Gal, Gln and Pyr. In cancer PC12 and HCT116 cells, a large increase in O2 consumption rate (OCR) upon uncoupling was only seen when Gln was combined with either Glc or Pyr. Inhibition of glutaminolysis with BPTES abolished this effect. Despite the key role of Gln, addition of FCCP inhibited respiration and induced apoptosis in cells supplied with Gln alone or Gal/Gln. For all substrate combinations, amplitude of respiratory responses to FCCP did not correlate with Akt, Erk and AMPK phosphorylation, cellular ATP, and resting OCR, mitochondrial Ca(2+) or membrane potential. However, we propose that proton motive force could modulate respiratory response to FCCP by regulating mitochondrial transport of Gln and Pyr, which decreases upon mitochondrial depolarisation. As a result, an increase in respiration upon uncoupling is abolished in cells, deprived of Gln or Pyr (Glc). Unlike PC12 or HCT116 cells, mouse embryonic fibroblasts were capable of generating pronounced response to FCCP when deprived of Gln, thus exhibiting lower dependence on glutaminolysis. Overall, the differential regulation of the respiratory response to FCCP by metabolic environment suggests that mitochondrial uncoupling has a potential for substrate-specific inhibition of cell function, and can be explored for selective cancer treatment.
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Affiliation(s)
- Alexander V Zhdanov
- Biochemistry Department, University College Cork, Cavanagh Pharmacy Building, College Road, Cork, Ireland.
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13
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Chronic hypoxia leads to a glycolytic phenotype and suppressed HIF-2 signaling in PC12 cells. Biochim Biophys Acta Gen Subj 2013; 1830:3553-69. [DOI: 10.1016/j.bbagen.2013.02.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 01/22/2013] [Accepted: 02/15/2013] [Indexed: 12/12/2022]
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14
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Bafilomycin A1 activates HIF-dependent signalling in human colon cancer cells via mitochondrial uncoupling. Biosci Rep 2013; 32:587-95. [PMID: 22943412 PMCID: PMC3497721 DOI: 10.1042/bsr20120085] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mitochondrial uncoupling is implicated in many patho(physiological) states. Using confocal live cell imaging and an optical O2 sensing technique, we show that moderate uncoupling of the mitochondria with plecomacrolide Baf (bafilomycin A1) causes partial depolarization of the mitochondria and deep sustained deoxygenation of human colon cancer HCT116 cells subjected to 6% atmospheric O2. A decrease in iO2 (intracellular O2) to 0–10 μM, induced by Baf, is sufficient for stabilization of HIFs (hypoxia inducible factors) HIF-1α and HIF-2α, coupled with an increased expression of target genes including GLUT1 (glucose transporter 1), HIF PHD2 (prolyl hydroxylase domain 2) and CAIX (carbonic anhydrase IX). Under the same hypoxic conditions, treatment with Baf causes neither decrease in iO2 nor HIF-α stabilization in the low-respiring HCT116 cells deficient in COX (cytochrome c-oxidase). Both cell types display equal capacities for HIF-α stabilization by hypoxia mimetics DMOG (dimethyloxalylglycine) and CoCl2, thus suggesting that the effect of Baf under hypoxia is driven mainly by mitochondrial respiration. Altogether, by activating HIF signalling under moderate hypoxia, mitochondrial uncoupling can play an important regulatory role in colon cancer metabolism and modulate adaptation of cancer cells to natural hypoxic environments.
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15
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Ingram JM, Zhang C, Xu J, Schiff SJ. FRET excited ratiometric oxygen sensing in living tissue. J Neurosci Methods 2013; 214:45-51. [PMID: 23333398 DOI: 10.1016/j.jneumeth.2013.01.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 01/03/2013] [Accepted: 01/05/2013] [Indexed: 12/26/2022]
Abstract
Dynamic analysis of oxygen (O₂) has been limited by the lack of a real-time, quantitative, and biocompatible sensor. To address these demands, we designed a ratiometric optode matrix consisting of the phosphorescence quenching dye platinum (II) octaethylporphine ketone (PtOEPK) and nanocystal quantum dots (NQDs), which when embedded within an inert polymer matrix allows long-term pre-designed excitation through fluorescence resonance energy transfer (FRET). Depositing this matrix on various glass substrates allowed the development of a series of optical sensors able to measure interstitial oxygen concentration [O₂] with several hundred millisecond temporal resolution in varying biological microdomains of active brain tissue.
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Affiliation(s)
- Justin M Ingram
- Center for Neural Engineering, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, USA.
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Dmitriev RI, Zhdanov AV, Jasionek G, Papkovsky DB. Assessment of Cellular Oxygen Gradients with a Panel of Phosphorescent Oxygen-Sensitive Probes. Anal Chem 2012; 84:2930-8. [DOI: 10.1021/ac3000144] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Optical probes and techniques for O2 measurement in live cells and tissue. Cell Mol Life Sci 2012; 69:2025-39. [PMID: 22249195 PMCID: PMC3371327 DOI: 10.1007/s00018-011-0914-0] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 12/19/2011] [Accepted: 12/29/2011] [Indexed: 01/03/2023]
Abstract
In recent years, significant progress has been achieved in the sensing and imaging of molecular oxygen (O2) in biological samples containing live cells and tissue. We review recent developments in the measurement of O2 in such samples by optical means, particularly using the phosphorescence quenching technique. The main types of soluble O2 sensors are assessed, including small molecule, supramolecular and particle-based structures used as extracellular or intracellular probes in conjunction with different detection modalities and measurement formats. For the different O2 sensing systems, particular attention is paid to their merits and limitations, analytical performance, general convenience and applicability in specific biological applications. The latter include measurement of O2 consumption rate, sample oxygenation, sensing of intracellular O2, metabolic assessment of cells, and O2 imaging of tissue, vasculature and individual cells. Altogether, this gives the potential user a comprehensive guide for the proper selection of the appropriate optical probe(s) and detection platform to suit their particular biological applications and measurement requirements.
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Glucose metabolism determines resistance of cancer cells to bioenergetic crisis after cytochrome-c release. Mol Syst Biol 2011; 7:470. [PMID: 21364572 PMCID: PMC3094064 DOI: 10.1038/msb.2011.2] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 01/19/2011] [Indexed: 01/19/2023] Open
Abstract
How can cancer cells survive the consequences of cyt-c release? Huber et al provide a quantitative analysis of the protective role of enhanced glucose utilization in cancer cells and investigate the impact of cell-to-cell heterogeneity in mitochondrial bioenergetics.
How can cancer cells survive the consequences of cyt-c release? Huber et al provide a quantitative analysis of the protective role of enhanced glucose utilization in cancer cells and investigate the impact of cell-to-cell heterogeneity in mitochondrial bioenergetics.
We combine ordinary differential equations based computational modelling, single-cell microscopy and in biochemistry assays to provide the first integrated system study to portray the bioenergetic crisis in cell populations subsequent to cytochrome-c (cyt-c) release; a hallmark during chemotherapeutically induced cell death. We experimentally identified a cell-to-cell heterogeneity in the dynamics of the ATP synthase subsequent to cyt-c release, which the model explained by variations in (i) accessible cytochrome-c after release and (ii) the cell's glycolytic capacity. Our model predicted, and single-cell imaging confirmed, that high (increasing) glucose in media was able to sustain (repolarise) ΔΨm in HeLa cervical cancer and MCF-7 breast cancer cells, suggesting that they might recover from bioenergetic crisis upon elevation of glucose. However, no significant repolarisation was found in non-transformed human epithelial CRL-1807 cells. Therefore, this mechanism may provide cancer cells with a competitive advantage to evade cell death induced by anticancer drugs or other stress conditions when compared with non-transformed cells.
How can cells cope with a bioenergetic crisis? In particular, how can cancer cells survive the bioenergetic consequences of cyt-c release that are often induced by chemotherapeutic agents, and that lead to depolarisation of the mitochondrial membrane potential ΔΨm, result in loss of ionic homeostasis and induce cell death? Is there an inherent population heterogeneity that can lead to a non-synchronous response to above cell death stimuli, thereby aggravating treatment and contributing to clinical relapse? Do cancer cells have a competitive advantage to non-transformed cells in averting such a bioenergetic crisis after cyt-c release. We have investigated these questions in our study, which we regard as the first rigorous system study of single-cell bioenergetics subsequent to cyt-c release and one that bridges single-cell microscopy, in vitro analysis with ordinary differential equations (ODE) based modelling of bioenergetics pathways in the mitochondria and the cytosol. Several laboratories have so far investigated cyt-c release experimentally (Slee et al, 1999; Atlante et al, 2000; Goldstein et al, 2000; Luetjens et al, 2001; Plas et al, 2001; Waterhouse et al, 2001; Ricci et al, 2003; Colell et al, 2007; Dussmann et al, 2003a, 2003b) and isolated mitochondria (Chinopoulos and Adam-Vizi, 2009; Kushnareva et al, 2002; Kushnareva et al, 2001). However, the cause and mechanistic of several key findings remain elusive and need a system level understanding of post-cyt-c release bioenergetic and its potential cross-talk to apoptosis signalling. Ricci et al (2003) have identified that the cell death-inducing protease caspase-3, which get activated upon cyt-c release, can further impair mitochondrial function by cleaving and deactivating respiratory complexes I and II. We addressed the question of how such a mechanism could potentiate a bioenergetic crisis. To do so, we first assembled our ODE-based model by integrating approaches from metabolic modelling (Beard, 2005; Beard and Qian, 2007; Dash and Beard, 2008) and calibrated the model to literature data that describe bioenergetic state variables (mitochondrial membrane potential ΔΨm, mitochondrial transmembrane membrane ΔpH, respiration ratio between respiring and resting state mitochondria). By remodelling cyt-c release as observed experimentally and integrating it into our model as input, the single-cell model was able to correctly describe the kinetics of ΔΨm depolarisation and allowed its quantification. Moreover, it suggested that an additional complex I/II cleavage may further impair respiration and depolarise ΔΨm by approximately further 10%. It was further reported that ATP synthase reversal, a change of direction in the ATP-producing enzyme that leads to pumping of protons from the mitochondrial matrix into the intramembrane space, can stabilise ΔΨm. By a remnant ΔΨm polarisation, cycling of Na+, Ca2+, K+, Cl− ions and protons across the mitochondrial and the plasma membranes is preserved, and ionic homeostasis can be maintained (Nicholls and Budd, 2000; Dussmann et al, 2003a; Chinopoulos and Adam-Vizi, 2009; Garedew et al, 2010). Our model confirmed that ATP synthase activity was reversed 10 min after onset of cyt-c release, predicted that ATP synthase reversal consumed ATP and that glycolysis was required and sufficient to provide the necessary ATP to sustain this reversal. Reverting back to our single-cell HeLa system, we confirmed the presence of ATP synthase reversal. However, reversal was only present in 20% of cells, 65% of cells showed no detectable reaction and even 15% maintained ATP synthase in forward direction. To explain this cell-to-cell heterogeneity, we modelled that a cyt-c fraction remains accessible by respiratory complexes and for respiration subsequent to release, which we denoted as ‘respiration-accessible cyt-c'. Our model suggested that small variations in such levels can sufficiently explain the experimentally detected population heterogeneity in the direction and amount of ATP synthase proton flux (Figure 6AB). Variations in respiration-accessible cyt-c may arise from incomplete mitochondrial release. Such incomplete release has been associated with failure of cristae remodelling in the absence of the BH3-only family member BID or the intramitochondrial protein OPA1 (Frezza et al, 2006; Scorrano et al, 2002). As the model identified glycolysis as necessary for sustaining ATP synthase reversal, we next investigated cells cultured in a medium that contained Na-pyruvate instead of glucose and which consequently were not able to perform glycolysis. We found that such cell populations had a significantly higher fraction of cells that maintained ATP synthase in forward mode consistent with our model predictions. The common influence of respiration-accessible cyt-c and the cell's ability to perform glycolysis is summarised in Figure 7A. Because glycolysis was able to influence ATP synthase proton pumping, which can affect ΔΨm levels, we investigating the effect of higher glucose in single cells. Our model predicted that an increase in glucose utilisation that generates higher cytosolic ATP levels is able to stabilise and repolarise ΔΨm and after release. This mechanism is independent from ATP synthase direction. For cells that have ATP synthase in reverse mode, elevated ATP leads to increased proton efflux from the matrix, cell populations that maintain ATP synthase in forward mode achieve a similar result through a reduction of proton influx at increased ATP. In both cases, the proton gradient along the inner membrane, and therefore ΔΨm, is increased as a consequence of ATP elevation. The mechanism is depicted in Figure 7B. We confirmed our model predictions that high glucose was able to stabilise (cells maintained in high-glucose media) and/or to repolarise (cells where glucose was added subsequent to release) ΔΨm (Figure 6). While a similar recovery was also present in MCF7 breast cancer cell lines, no significant effect of elevated glucose was found in non-transformed CRL-1807 cells. In conjunction with an impairment of caspase-dependent cell death observed in many human cancers, cancer cells may use this mechanism, and this mechanism may provide cancer cells with a competitive advantage to evade cell death induced by anticancer drugs or other stress conditions when compared with non-transformed cells. Many anticancer drugs activate caspases via the mitochondrial apoptosis pathway. Activation of this pathway triggers a concomitant bioenergetic crisis caused by the release of cytochrome-c (cyt-c). Cancer cells are able to evade these processes by altering metabolic and caspase activation pathways. In this study, we provide the first integrated system study of mitochondrial bioenergetics and apoptosis signalling and examine the role of mitochondrial cyt-c release in these events. In accordance with single-cell experiments, our model showed that loss of cyt-c decreased mitochondrial respiration by 95% and depolarised mitochondrial membrane potential ΔΨm from −142 to −88 mV, with active caspase-3 potentiating this decrease. ATP synthase was reversed under such conditions, consuming ATP and stabilising ΔΨm. However, the direction and level of ATP synthase activity showed significant heterogeneity in individual cancer cells, which the model explained by variations in (i) accessible cyt-c after release and (ii) the cell's glycolytic capacity. Our results provide a quantitative and mechanistic explanation for the protective role of enhanced glucose utilisation for cancer cells to avert the otherwise lethal bioenergetic crisis associated with apoptosis initiation.
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Huber HJ, Duessmann H, Wenus J, Kilbride SM, Prehn JHM. Mathematical modelling of the mitochondrial apoptosis pathway. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1813:608-15. [PMID: 20950651 DOI: 10.1016/j.bbamcr.2010.10.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2010] [Revised: 09/29/2010] [Accepted: 10/04/2010] [Indexed: 12/23/2022]
Abstract
Mitochondria are pivotal for cellular bioenergetics, but are also a core component of the cell death machinery. Hypothesis-driven research approaches have greatly advanced our understanding of the role of mitochondria in cell death and cell survival, but traditionally focus on a single gene or specific signalling pathway at a time. Predictions originating from these approaches become limited when signalling pathways show increased complexity and invariably include redundancies, feedback loops, anisotropies or compartmentalisation. By introducing methods from theoretical chemistry, control theory, and biophysics, computational models have provided new quantitative insights into cell decision processes and have led to an increased understanding of the key regulatory principles of apoptosis. In this review, we describe the currently applied modelling approaches, discuss the suitability of different modelling techniques, and evaluate their contribution to the understanding of the mitochondrial apoptosis pathway. This article is part of a Special Issue entitled Mitochondria: the deadly organelle.
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Affiliation(s)
- Heinrich J Huber
- Department of Physiology and Mental Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
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Sato Y, Endo H, Okuyama H, Takeda T, Iwahashi H, Imagawa A, Yamagata K, Shimomura I, Inoue M. Cellular hypoxia of pancreatic beta-cells due to high levels of oxygen consumption for insulin secretion in vitro. J Biol Chem 2011; 286:12524-32. [PMID: 21296882 DOI: 10.1074/jbc.m110.194738] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cellular oxygen consumption is a determinant of intracellular oxygen levels. Because of the high demand of mitochondrial respiration during insulin secretion, pancreatic β-cells consume large amounts of oxygen in a short time period. We examined the effect of insulin secretion on cellular oxygen tension in vitro. We confirmed that Western blotting of pimonidazole adduct was more sensitive than immunostaining for detection of cellular hypoxia in vitro and in vivo. The islets of the diabetic mice but not those of normal mice were hypoxic, especially when a high dose of glucose was loaded. In MIN6 cells, a pancreatic β-cell line, pimonidazole adduct formation and stabilization of hypoxia-inducible factor-1α (HIF-1α) were detected under mildly hypoxic conditions. Inhibition of respiration rescued the cells from becoming hypoxic. Glucose stimulation decreased cellular oxygen levels in parallel with increased insulin secretion and mitochondrial respiration. The cellular hypoxia by glucose stimulation was also observed in the isolated islets from mice. The MIN6 cells overexpressing HIF-1α were resistant to becoming hypoxic after glucose stimulation. Thus, glucose-stimulated β-cells can become hypoxic by oxygen consumption, especially when the oxygen supply is impaired.
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Affiliation(s)
- Yoshifumi Sato
- Department of Biochemistry, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3 Nakamichi, Higashinari-ku, Osaka 537-8511
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Monitoring of Cellular Dynamics with Electrochemical Detection Techniques. MODERN ASPECTS OF ELECTROCHEMISTRY 2011. [DOI: 10.1007/978-1-4614-0347-0_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Dmitriev RI, Ropiak HM, Yashunsky DV, Ponomarev GV, Zhdanov AV, Papkovsky DB. Bactenecin 7 peptide fragment as a tool for intracellular delivery of a phosphorescent oxygen sensor. FEBS J 2010; 277:4651-61. [DOI: 10.1111/j.1742-4658.2010.07872.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Zhdanov AV, Dmitriev RI, Papkovsky DB. Bafilomycin A1 activates respiration of neuronal cells via uncoupling associated with flickering depolarization of mitochondria. Cell Mol Life Sci 2010; 68:903-17. [PMID: 20820851 PMCID: PMC3037485 DOI: 10.1007/s00018-010-0502-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 07/08/2010] [Accepted: 08/06/2010] [Indexed: 10/27/2022]
Abstract
Bafilomycin A1 (Baf) induces an elevation of cytosolic Ca(2+) and acidification in neuronal cells via inhibition of the V-ATPase. Also, Baf uncouples mitochondria in differentiated PC12 ((d)PC12), (d)SH-SY5Y cells and cerebellar granule neurons, and markedly elevates their respiration. This respiratory response in (d)PC12 is accompanied by morphological changes in the mitochondria and decreases the mitochondrial pH, Ca(2+) and ΔΨm. The response to Baf is regulated by cytosolic Ca(2+) fluxes from the endoplasmic reticulum. Inhibition of permeability transition pore opening increases the depolarizing effect of Baf on the ΔΨm. Baf induces stochastic flickering of the ΔΨm with a period of 20 ± 10 s. Under conditions of suppressed ATP production by glycolysis, oxidative phosphorylation impaired by Baf does not provide cells with sufficient ATP levels. Cells treated with Baf become more susceptible to excitation with KCl. Such mitochondrial uncoupling may play a role in a number of (patho)physiological conditions induced by Baf.
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Affiliation(s)
- Alexander V Zhdanov
- Biochemistry Department, University College Cork, Cavanagh Pharmacy Building, College Road, Cork, Republic of Ireland.
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Extracellular calcium depletion transiently elevates oxygen consumption in neurosecretory PC12 cells through activation of mitochondrial Na+/Ca2+ exchange. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1627-37. [DOI: 10.1016/j.bbabio.2010.06.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 05/31/2010] [Accepted: 06/09/2010] [Indexed: 11/18/2022]
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Zhdanov AV, Ogurtsov VI, Taylor CT, Papkovsky DB. Monitoring of cell oxygenation and responses to metabolic stimulation by intracellular oxygen sensing technique. Integr Biol (Camb) 2010; 2:443-51. [DOI: 10.1039/c0ib00021c] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Alexander V. Zhdanov
- Biochemistry Department, University College Cork, Cavanagh Pharmacy Building, College Road, Cork, Ireland. Fax: + 353-21-4901698; Tel: + 353-21-4901698
| | - Vladimir I. Ogurtsov
- Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork, Ireland
| | - Cormac T. Taylor
- Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Dmitri B. Papkovsky
- Biochemistry Department, University College Cork, Cavanagh Pharmacy Building, College Road, Cork, Ireland. Fax: + 353-21-4901698; Tel: + 353-21-4901698
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Mitochondrial pyrimidine nucleotide carrier (PNC1) regulates mitochondrial biogenesis and the invasive phenotype of cancer cells. Oncogene 2010; 29:3964-76. [PMID: 20453889 DOI: 10.1038/onc.2010.146] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The insulin-like growth factor (IGF-I) signalling pathway is essential for metabolism, cell growth and survival. It induces expression of the mitochondrial pyrimidine nucleotide carrier 1 (PNC1) in transformed cells, but the consequences of this for cell phenotype are unknown. Here we show that PNC1 is necessary to maintain mitochondrial function by controlling mitochondrial DNA replication and the ratio of transcription of mitochondrial genes relative to nuclear genes. PNC1 suppression causes reduced oxidative phosphorylation and leakage of reactive oxygen species (ROS), which activates the AMPK-PGC1alpha signalling pathway and promotes mitochondrial biogenesis. Overexpression of PNC1 suppresses mitochondrial biogenesis. Suppression of PNC1 causes a profound ROS-dependent epithelial-mesenchymal transition (EMT), whereas overexpression of PNC1 suppresses both basal EMT and induction of EMT by TGF-beta. Overall, our findings indicate that PNC1 is essential for mitochondria maintenance and suggest that its induction by IGF-I facilitates cell growth whereas protecting cells from an ROS-promoted differentiation programme that arises from mitochondrial dysfunction.
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Guaccio A, Netti PA. Monitoring oxygen uptake in 3D tissue engineering scaffolds by phosphorescence quenching microscopy. Biotechnol Prog 2010; 26:1494-500. [DOI: 10.1002/btpr.438] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Dmitriev RI, Zhdanov AV, Ponomarev GV, Yashunski DV, Papkovsky DB. Intracellular oxygen-sensitive phosphorescent probes based on cell-penetrating peptides. Anal Biochem 2010; 398:24-33. [DOI: 10.1016/j.ab.2009.10.048] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 10/16/2009] [Accepted: 10/19/2009] [Indexed: 10/20/2022]
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Abstract
The changes that occur in electrochemical gradients across biological membranes provide us with invaluable information on physiological responses, pathophysiological processes and drug actions/toxicity. This chapter aims to provide researchers with sufficient information to carry out a quantitative assessment of mitochondrial energetics at a single-cell level thereby providing output on changes in the mitochondrial membrane potential (Deltapsi(m)) through the utilization of potentiometric fluorescent probes (TMRM, TMRE, Rhodamine 123). As these cationic probes behave in a Nernstian fashion, changes at the plasma membrane potential (Deltapsi(p)) need also to be accounted for in order to validate the responses obtained with Deltapsi(m)-sensitive fluorescent probes. To this end techniques that utilize Deltapsi(p)-sensitive anionic fluorescent probes to monitor changes in the plasma membrane potential will also be discussed. In many biological systems multiple changes occur at both a Deltapsi(m) and Deltapsi(p) level that often makes the interpretation of the cationic fluorescent responses much more difficult. This problem has driven the development of computational modelling techniques that utilize the redistribution properties of the cationic and anionic fluorescent probes within the cell to provide output on changes in Deltapsi(m) and Deltapsi(p).
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Fercher A, Ponomarev GV, Yashunski D, Papkovsky D. Evaluation of the derivates of phosphorescent Pt-coproporphyrin as intracellular oxygen-sensitive probes. Anal Bioanal Chem 2010; 396:1793-803. [DOI: 10.1007/s00216-009-3399-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 12/10/2009] [Accepted: 12/10/2009] [Indexed: 10/20/2022]
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Abstract
Many parameters reflecting mitochondrial function and metabolic status of the cell, including the mitochondrial membrane potential, reactive oxygen species, ATP, NADH, ion gradients, and ion fluxes (Ca(2+), H(+)), are amenable for analysis by live cell imaging and are widely used in many labs. However, one key metabolite - cellular oxygen - is currently not analyzed routinely. Here we present several imaging techniques that use the phosphorescent oxygen-sensitive probes loaded intracellularly and which allow real-time monitoring of O(2) in live respiring cells and metabolic responses to cell stimulation. The techniques include conventional wide-field fluorescence microscopy to monitor relative changes in cell respiration, microsecond FLIM format which provides quantitative readout of O(2) concentration within/near the cells, and live cell array devices for the monitoring of metabolic responses of individual suspension cells. Step by step procedures of typical experiments for each of these applications and troubleshooting guide are given.
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Larbi A, Cabreiro F, Zelba H, Marthandan S, Combet E, Friguet B, Petropoulos I, Barnett Y, Pawelec G. Reduced oxygen tension results in reduced human T cell proliferation and increased intracellular oxidative damage and susceptibility to apoptosis upon activation. Free Radic Biol Med 2010; 48:26-34. [PMID: 19796677 DOI: 10.1016/j.freeradbiomed.2009.09.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 09/21/2009] [Accepted: 09/23/2009] [Indexed: 11/25/2022]
Abstract
Cell culture and in vitro models are the basis for much biological research, especially in human immunology. Ex vivo studies of T cell physiology employ conditions attempting to mimic the in vivo situation as closely as possible. Despite improvements in controlling the cellular milieu in vitro, most of what is known about T cell behavior in vitro is derived from experiments on T cells exposed to much higher oxygen levels than are normal in vivo. In this study, we report a reduced proliferative response and increased apoptosis susceptibility after T cell activation at 2% oxygen compared to in air. To explain this observation, we tested the hypothesis of an impaired efficacy of intracellular protective mechanisms including antioxidant levels, oxidized protein repair (methionine sulfoxide reductases), and degradation (proteasome) activities. Indeed, after activation, there was a significant accumulation of intracellular oxidized proteins at more physiological oxygen levels concomitant with a reduced GSH:GSSG ratio. Proteasome and methionine sulfoxide reductase activities were also reduced. These data may explain the increased apoptotic rate observed at more physiological oxygen levels. Altogether, this study highlights the importance of controlling oxygen levels in culture when investigating oxygen-dependent phenomena such as oxidative stress.
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Affiliation(s)
- Anis Larbi
- Center for Medical Research, Tübingen Aging and Tumor Immunology Group, University of Tübingen, 72072 Tübingen, Germany.
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Wenus J, Düssmann H, Paul P, Kalamatianos D, Rehm M, Wellstead PE, Prehn JH, Huber HJ. ALISSA: an automated live-cell imaging system for signal transduction analyses. Biotechniques 2009; 47:1033-40. [DOI: 10.2144/000113247] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Probe photobleaching and a specimen's sensitivity to phototoxicity severely limit the number of possible excitation cycles in time-lapse fluorescent microscopy experiments. Consequently, when a study of cellular processes requires measurements over hours or days, temporal resolution is limited, and spontaneous or rapid events may be missed, thus limiting conclusions about transduction events. We have developed ALISSA, a design framework and reference implementation for an automated live-cell imaging system for signal transduction analysis. It allows an adaptation of image modalities and laser resources tailored to the biological process, and thereby extends temporal resolution from minutes to seconds. The system employs online image analysis to detect cellular events that are then used to exercise microscope control. It consists of a reusable image analysis software for cell segmentation, tracking, and time series extraction, and a measurement-specific process control software that can be easily adapted to various biological settings. We have applied the ALISSA framework to the analysis of apoptosis as a demonstration case for slow onset and rapid execution signaling. The demonstration provides a clear proof-of-concept for ALISSA, and offers guidelines for its application in a broad spectrum of signal transduction studies.
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Affiliation(s)
- Jakub Wenus
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Heiko Düssmann
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Perrine Paul
- Hamilton Institute, National University of Ireland Maynooth, Maynooth, Ireland
| | | | - Markus Rehm
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Peter E. Wellstead
- Hamilton Institute, National University of Ireland Maynooth, Maynooth, Ireland
| | - Jochen H.M. Prehn
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Heinrich J. Huber
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
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PGC-1alpha is coupled to HIF-1alpha-dependent gene expression by increasing mitochondrial oxygen consumption in skeletal muscle cells. Proc Natl Acad Sci U S A 2009; 106:2188-93. [PMID: 19179292 DOI: 10.1073/pnas.0808801106] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial biogenesis occurs in response to increased cellular ATP demand. The mitochondrial electron transport chain requires molecular oxygen to produce ATP. Thus, increased ATP generation after mitochondrial biogenesis results in increased oxygen demand that must be matched by a corresponding increase in oxygen supply. We found that overexpression of peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PGC-1alpha), which increases mitochondrial biogenesis in primary skeletal muscle cells, leads to increased expression of a cohort of genes known to be regulated by the dimeric hypoxia-inducible factor (HIF), a master regulator of the adaptive response to hypoxia. PGC-1alpha-dependent induction of HIF target genes under physiologic oxygen concentrations is not through transcriptional coactivation of HIF or up-regulation of HIF-1alpha mRNA but through HIF-1alpha protein stabilization. It occurs because of intracellular hypoxia as a result of increased oxygen consumption after mitochondrial biogenesis. Thus, we propose that at physiologic oxygen concentrations, PGC-1alpha is coupled to HIF signaling through the regulation of intracellular oxygen availability, allowing cells and tissues to match increased oxygen demand after mitochondrial biogenesis with increased oxygen supply.
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