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Barnstable CJ, Zhang M, Tombran-Tink J. Uncoupling Proteins as Therapeutic Targets for Neurodegenerative Diseases. Int J Mol Sci 2022; 23:5672. [PMID: 35628482 PMCID: PMC9144266 DOI: 10.3390/ijms23105672] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/14/2022] [Accepted: 05/16/2022] [Indexed: 02/05/2023] Open
Abstract
Most of the major retinal degenerative diseases are associated with significant levels of oxidative stress. One of the major sources contributing to the overall level of stress is the reactive oxygen species (ROS) generated by mitochondria. The driving force for ROS production is the proton gradient across the inner mitochondrial membrane. This gradient can be modulated by members of the uncoupling protein family, particularly the widely expressed UCP2. The overexpression and knockout studies of UCP2 in mice have established the ability of this protein to provide neuroprotection in a number of animal models of neurological disease, including retinal diseases. The expression and activity of UCP2 are controlled at the transcriptional, translational and post-translational levels, making it an ideal candidate for therapeutic intervention. In addition to regulation by a number of growth factors, including the neuroprotective factors LIF and PEDF, small molecule activators of UCP2 have been found to reduce mitochondrial ROS production and protect against cell death both in culture and animal models of retinal degeneration. Such studies point to the development of new therapeutics to combat a range of blinding retinal degenerative diseases and possibly other diseases in which oxidative stress plays a key role.
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Affiliation(s)
- Colin J. Barnstable
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA;
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin 300384, China;
| | - Mingliang Zhang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin 300384, China;
| | - Joyce Tombran-Tink
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA;
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin 300384, China;
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2
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Hass DT, Barnstable CJ. Uncoupling proteins in the mitochondrial defense against oxidative stress. Prog Retin Eye Res 2021; 83:100941. [PMID: 33422637 DOI: 10.1016/j.preteyeres.2021.100941] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/28/2020] [Accepted: 01/03/2021] [Indexed: 02/06/2023]
Abstract
Oxidative stress is a major component of most major retinal diseases. Many extrinsic anti-oxidative strategies have been insufficient at counteracting one of the predominant intrinsic sources of reactive oxygen species (ROS), mitochondria. The proton gradient across the inner mitochondrial membrane is a key driving force for mitochondrial ROS production, and this gradient can be modulated by members of the mitochondrial uncoupling protein (UCP) family. Of the UCPs, UCP2 shows a widespread distribution and has been shown to uncouple oxidative phosphorylation, with concomitant decreases in ROS production. Genetic studies using transgenic and knockout mice have documented the ability of increased UCP2 activity to provide neuroprotection in models of a number of diseases, including retinal diseases, indicating that it is a strong candidate for a therapeutic target. Molecular studies have identified the structural mechanism of action of UCP2 and have detailed the ways in which its expression and activity can be controlled at the transcriptional, translational and posttranslational levels. These studies suggest a number of ways in control of UCP2 expression and activity can be used therapeutically for both acute and chronic conditions. The development of such therapeutic approaches will greatly increase the tools available to combat a broad range of serious retinal diseases.
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Affiliation(s)
- Daniel T Hass
- Department of Biochemistry, The University of Washington, Seattle, WA, 98109, USA
| | - Colin J Barnstable
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, 17033, USA.
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3
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Nunn AVW, Guy GW, Botchway SW, Bell JD. From sunscreens to medicines: Can a dissipation hypothesis explain the beneficial aspects of many plant compounds? Phytother Res 2020; 34:1868-1888. [PMID: 32166791 PMCID: PMC7496984 DOI: 10.1002/ptr.6654] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 01/16/2020] [Accepted: 02/16/2020] [Indexed: 12/17/2022]
Abstract
Medicine has utilised plant‐based treatments for millennia, but precisely how they work is unclear. One approach is to use a thermodynamic viewpoint that life arose by dissipating geothermal and/or solar potential. Hence, the ability to dissipate energy to maintain homeostasis is a fundamental principle in all life, which can be viewed as an accretion system where layers of complexity have built upon core abiotic molecules. Many of these compounds are chromophoric and are now involved in multiple pathways. Plants have further evolved a plethora of chromophoric compounds that can not only act as sunscreens and redox modifiers, but also have now become integrated into a generalised stress adaptive system. This could be an extension of the dissipative process. In animals, many of these compounds are hormetic, modulating mitochondria and calcium signalling. They can also display anti‐pathogen effects. They could therefore modulate bioenergetics across all life due to the conserved electron transport chain and proton gradient. In this review paper, we focus on well‐described medicinal compounds, such as salicylic acid and cannabidiol and suggest, at least in animals, their activity reflects their evolved function in plants in relation to stress adaptation, which itself evolved to maintain dissipative homeostasis.
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Affiliation(s)
- Alistair V W Nunn
- Research Centre for Optimal Health, Department of Life Sciences, University of Westminster, London, UK
| | | | - Stanley W Botchway
- STFC, UKRI & Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
| | - Jimmy D Bell
- Research Centre for Optimal Health, Department of Life Sciences, University of Westminster, London, UK
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4
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Liberatore KL, Dukowic-Schulze S, Miller ME, Chen C, Kianian SF. The role of mitochondria in plant development and stress tolerance. Free Radic Biol Med 2016; 100:238-256. [PMID: 27036362 DOI: 10.1016/j.freeradbiomed.2016.03.033] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/25/2016] [Accepted: 03/28/2016] [Indexed: 01/03/2023]
Abstract
Eukaryotic cells require orchestrated communication between nuclear and organellar genomes, perturbations in which are linked to stress response and disease in both animals and plants. In addition to mitochondria, which are found across eukaryotes, plant cells contain a second organelle, the plastid. Signaling both among the organelles (cytoplasmic) and between the cytoplasm and the nucleus (i.e. nuclear-cytoplasmic interactions (NCI)) is essential for proper cellular function. A deeper understanding of NCI and its impact on development, stress response, and long-term health is needed in both animal and plant systems. Here we focus on the role of plant mitochondria in development and stress response. We compare and contrast features of plant and animal mitochondrial genomes (mtDNA), particularly highlighting the large and highly dynamic nature of plant mtDNA. Plant-based tools are powerful, yet underutilized, resources for enhancing our fundamental understanding of NCI. These tools also have great potential for improving crop production. Across taxa, mitochondria are most abundant in cells that have high energy or nutrient demands as well as at key developmental time points. Although plant mitochondria act as integrators of signals involved in both development and stress response pathways, little is known about plant mtDNA diversity and its impact on these processes. In humans, there are strong correlations between particular mitotypes (and mtDNA mutations) and developmental differences (or disease). We propose that future work in plants should focus on defining mitotypes more carefully and investigating their functional implications as well as improving techniques to facilitate this research.
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Affiliation(s)
- Katie L Liberatore
- United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, St. Paul, MN 55108, United States; Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, United States.
| | | | - Marisa E Miller
- United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, St. Paul, MN 55108, United States; Department of Horticultural Science, University of Minnesota, St. Paul, MN 55108, United States
| | - Changbin Chen
- Department of Horticultural Science, University of Minnesota, St. Paul, MN 55108, United States
| | - Shahryar F Kianian
- United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, St. Paul, MN 55108, United States; Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, United States
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5
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Rurek M. Plant mitochondria under a variety of temperature stress conditions. Mitochondrion 2014; 19 Pt B:289-94. [DOI: 10.1016/j.mito.2014.02.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 02/12/2014] [Accepted: 02/14/2014] [Indexed: 10/25/2022]
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Figueira TRS, Arruda P. Differential expression of uncoupling mitochondrial protein and alternative oxidase in the plant response to stress. J Bioenerg Biomembr 2011; 43:67-70. [PMID: 21253844 DOI: 10.1007/s10863-011-9333-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Different cell types, organs and tissues shape their mitochondrial proteome according to the cellular environment that is dictated by differentiation, development and metabolic status. Under each circumstance, members of multigenic families that encode mitochondrial proteins are differentially expressed to meet the mitochondrial metabolic demand. However, the mitochondrial proteome may drastically change in response to stress conditions. Examples of the changes in mitochondrial protein expression caused by stress are represented by the energy-dissipating mitochondrial uncoupling protein (UCP) and alternative oxidase (AOx). UCP and AOx belong to multigenic families in plants, and their members, which are expressed in a time/tissue specific manner, respond differentially to stress conditions. In general, UCP and AOx are not expressed at the same levels concurrently in the same tissue, and the level of each protein varies in each stress condition. In addition, under non-stress conditions, UCP is expressed at much higher levels compared with AOx. The role of their differential expression in plant growth, development and response to stress is discussed.
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Affiliation(s)
- Thais Resende Silva Figueira
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
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Gonidi M, Athanassiadou AM, Patsouris E, Tsipis A, Dimopoulos S, Kyriakidou V, Chelidonis G, Athanassiadou P. Mitochondrial UCP4 and bcl-2 expression in imprints of breast carcinomas: relationship with DNA ploidy and classical prognostic factors. Pathol Res Pract 2011; 207:377-82. [PMID: 21621926 DOI: 10.1016/j.prp.2011.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 02/26/2011] [Accepted: 03/21/2011] [Indexed: 02/07/2023]
Abstract
Mitochondria are the bioenergetic and metabolic centers of cells and play an important role in the regulation of cell death. The mitochondrial apoptosis pathway is controlled by the bcl-2 protein family. Overexpression of mitochondrial uncoupling protein 4 (UCP4) can promote proliferation and inhibit apoptosis and differentiation. Imprint smears obtained from 124 tumors were studied immunocytochemically, and results were correlated with prognostic markers. There were 112 ductal and 12 lobular carcinomas. The positivity of UCP4 was correlated with lymph node metastases (p=0.005), positive ER and PR expression (p<0.0001 for both), as well as positivity for p53 (p<0.0001) and Ki-67 (p<0.0001). Decreased expression of bcl-2 correlated with increased expression of UCP4 (p=0.001). Regarding DNA ploidy, UCP4 positivity was correlated with aneuploid tumors (p=0.002). Negative expression of bcl-2 was correlated with poorly differentiated carcinomas (p<0.0001), as well as with positive expression of p53 (p<0.0001) and Ki-67 (p<0.0001). Logistic regression revealed that ploidy and p53 expression had an impact on UCP4. These findings encourage future investigations regarding the potential role of UCPs not only into mechanisms underlying breast cancer, but also as a novel candidate to the design and development of more effective therapeutic strategies.
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MESH Headings
- Adult
- Aged
- Aged, 80 and over
- Biomarkers, Tumor/analysis
- Breast Neoplasms/chemistry
- Breast Neoplasms/genetics
- Breast Neoplasms/pathology
- Breast Neoplasms/surgery
- Carcinoma, Ductal, Breast/chemistry
- Carcinoma, Ductal, Breast/genetics
- Carcinoma, Ductal, Breast/secondary
- Carcinoma, Ductal, Breast/surgery
- Carcinoma, Lobular/chemistry
- Carcinoma, Lobular/genetics
- Carcinoma, Lobular/secondary
- Carcinoma, Lobular/surgery
- Cell Differentiation
- Chi-Square Distribution
- Female
- Greece
- Humans
- Immunohistochemistry
- Ki-67 Antigen/analysis
- Logistic Models
- Lymphatic Metastasis
- Membrane Transport Proteins/analysis
- Middle Aged
- Mitochondrial Uncoupling Proteins
- Neoplasm Staging
- Ploidies
- Prognosis
- Proto-Oncogene Proteins c-bcl-2/analysis
- Receptor, ErbB-2/analysis
- Receptors, Estrogen/analysis
- Receptors, Progesterone/analysis
- Risk Assessment
- Risk Factors
- Tumor Suppressor Protein p53/analysis
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Affiliation(s)
- Maria Gonidi
- 1st Pathology Department and Cytology Unit, National & Kapodistrian University of Athens, Medical School, 75 Mikras Asias, 11527 Athens, Greece
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Schwartz TS, Murray S, Seebacher F. Novel reptilian uncoupling proteins: molecular evolution and gene expression during cold acclimation. Proc Biol Sci 2008; 275:979-85. [PMID: 18230589 DOI: 10.1098/rspb.2007.1761] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Many animals upregulate metabolism in response to cold. Uncoupling proteins (UCPs) increase proton conductance across the mitochondrial membrane and can thereby alleviate damage from reactive oxygen species that may form as a result of metabolic upregulation. Our aim in this study was to determine whether reptiles (Crocodylus porosus) possess UCP genes. If so, we aimed to place reptilian UCP genes within a phylogenetic context and to determine whether the expression of UCP genes is increased during cold acclimation. We provide the first evidence that UCP2 and UCP3 genes are present in reptiles. Unlike in other vertebrates, UCP2 and UPC3 are expressed in liver and skeletal muscle of the crocodile, and both are upregulated in liver during cold acclimation but not in muscle. We identified two transcripts of UCP3, one of which produces a truncated protein similar to the UCP3S transcript in humans, and the resulting protein lacks the predicted nucleotide-binding regulatory domain. Our molecular phylogeny suggests that uncoupling protein 1 (UCP1) is ancestral and has been lost in archosaurs. In birds, UCP3 may have assumed a similar function as UCP1 in mammals, which has important ramifications for understanding endothermic heat production.
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Affiliation(s)
- Tonia S Schwartz
- School of Biological Sciences, The University of Sydney, Sydney, NSW 2006, Australia
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Molecular identification of three Arabidopsis thaliana mitochondrial dicarboxylate carrier isoforms: organ distribution, bacterial expression, reconstitution into liposomes and functional characterization. Biochem J 2008; 410:621-9. [PMID: 18039180 DOI: 10.1042/bj20070867] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Screening of the Arabidopsis thaliana genome revealed three potential homologues of mammalian and yeast mitochondrial DICs (dicarboxylate carriers) designated as DIC1, DIC2 and DIC3, each belonging to the mitochondrial carrier protein family. DIC1 and DIC2 are broadly expressed at comparable levels in all the tissues investigated. DIC1-DIC3 have been reported previously as uncoupling proteins, but direct transport assays with recombinant and reconstituted DIC proteins clearly demonstrate that their substrate specificity is unique to plants, showing the combined characteristics of the DIC and oxaloacetate carrier in yeast. Indeed, the Arabidopsis DICs transported a wide range of dicarboxylic acids including malate, oxaloacetate and succinate as well as phosphate, sulfate and thiosulfate at high rates, whereas 2-oxoglutarate was revealed to be a very poor substrate. The role of these plant mitochondrial DICs is discussed with respect to other known mitochondrial carrier family members including uncoupling proteins. It is proposed that plant DICs constitute the membrane component of several metabolic processes including the malate-oxaloacetate shuttle, the most important redox connection between the mitochondria and the cytosol.
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Arnholdt-Schmitt B, Costa JH, de Melo DF. AOX--a functional marker for efficient cell reprogramming under stress? TRENDS IN PLANT SCIENCE 2006; 11:281-7. [PMID: 16713324 DOI: 10.1016/j.tplants.2006.05.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2005] [Revised: 04/03/2006] [Accepted: 05/02/2006] [Indexed: 05/09/2023]
Abstract
Functional markers for stress tolerance can be used in plant breeding to identify genotypes with high yield stabilities under various conditions. Thus, a good marker should show a strong correlation with favourable adaptive plant behaviour. The efficient reprogramming of target cells for yield determination is currently considered to be the most important step towards defining abiotic stress tolerance. In this Opinion article, we propose a role for the alternative oxidase (AOX) gene as a marker for genetic variation in cell reprogramming and yield stability. Evidence to support this idea comes from the metabolic role of alternative respiration under stress, the link between AOX activity and differential growth, and the single nucleotide polymorphism recently observed in AOX genes. We propose an innovative, interdisciplinary and global research strategy for future experimentation on AOX genes that could have an application in plant breeding.
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Vercesi AE, Borecký J, Maia IDG, Arruda P, Cuccovia IM, Chaimovich H. Plant uncoupling mitochondrial proteins. ANNUAL REVIEW OF PLANT BIOLOGY 2006; 57:383-404. [PMID: 16669767 DOI: 10.1146/annurev.arplant.57.032905.105335] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Uncoupling proteins (UCPs) are membrane proteins that mediate purine nucleotide-sensitive free fatty acid-activated H(+) flux through the inner mitochondrial membrane. After the discovery of UCP in higher plants in 1995, it was acknowledged that these proteins are widely distributed in eukaryotic organisms. The widespread presence of UCPs in eukaryotes implies that these proteins may have functions other than thermogenesis. In this review, we describe the current knowledge of plant UCPs, including their discovery, biochemical properties, distribution, gene family, gene expression profiles, regulation of gene expression, and evolutionary aspects. Expression analyses and functional studies on the plant UCPs under normal and stressful conditions suggest that UCPs regulate energy metabolism in the cellular responses to stress through regulation of the electrochemical proton potential (Deltamu(H)+) and production of reactive oxygen species.
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Affiliation(s)
- Aníbal Eugênio Vercesi
- Laboratório de Bioenergética, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-970, Campinas, SP, Brazil.
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