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Caggiano EG, Taniguchi CM. UCP2 and pancreatic cancer: conscious uncoupling for therapeutic effect. Cancer Metastasis Rev 2024; 43:777-794. [PMID: 38194152 PMCID: PMC11156755 DOI: 10.1007/s10555-023-10157-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 11/13/2023] [Indexed: 01/10/2024]
Abstract
Pancreatic cancer has an exaggerated dependence on mitochondrial metabolism, but methods to specifically target the mitochondria without off target effects in normal tissues that rely on these organelles is a significant challenge. The mitochondrial uncoupling protein 2 (UCP2) has potential as a cancer-specific drug target, and thus, we will review the known biology of UCP2 and discuss its potential role in the pathobiology and future therapy of pancreatic cancer.
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Affiliation(s)
- Emily G Caggiano
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Cullen M Taniguchi
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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2
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Wang YY, Liu H, Li SJ, Feng B, Huang YQ, Liu SB, Yang YL. Ucp4 Knockdown of Cerebellar Purkinje Cells Induces Bradykinesia. Mol Neurobiol 2024; 61:1119-1139. [PMID: 37688710 PMCID: PMC10861399 DOI: 10.1007/s12035-023-03607-1] [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: 02/14/2023] [Accepted: 08/22/2023] [Indexed: 09/11/2023]
Abstract
Although uncoupling protein 4 (UCP4) is the most abundant protein reported in the brain, the biological function of UCP4 in cerebellum and pathological outcome of UCP4 deficiency in cerebellum remain obscure. To evaluate the role of Ucp4 in the cerebellar Purkinje cells (PCs), we generated the conditional knockdown of Ucp4 in PCs (Pcp2cre;Ucp4fl/fl mice) by breeding Ucp4fl/fl mice with Pcp2cre mice. Series results by Western blot, immunofluorescent staining, and triple RNAscope in situ hybridization confirmed the specific ablation of Ucp4 in PCs in Pcp2cre;Ucp4fl/fl mice, but did not affect the expression of Ucp2, the analog of Ucp4. Combined behavioral tests showed that Pcp2cre;Ucp4fl/fl mice displayed a characteristic bradykinesia in the spontaneous movements. The electromyogram recordings detection excluded the possibility of hypotonia in Pcp2cre;Ucp4fl/fl mice. And the electrical patch clamp recordings showed the altered properties of PCs in Pcp2cre;Ucp4fl/fl mice. Moreover, transmission electron microscope (TEM) results showed the increased mitochondrial circularity in PCs; ROS probe imaging showed the increased ROS generation in molecular layer; and finally, microplate reader assay showed the significant changes of mitochondrial functions, including ROS, ATP, and MMP in the isolated cerebellum tissue. The results suggested that the specific knockdown of mitochondrial protein Ucp4 could damage PCs possibly by attacking their mitochondrial function. The present study is the first to report a close relationship between UCP4 deletion with PCs impairment, and suggests the importance of UCP4 in the substantial support of mitochondrial function homeostasis in bradykinesia. UCP4 might be a therapeutic target for the cerebellar-related movement disorder.
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Affiliation(s)
- Ya-Yun Wang
- National Teaching Demonstration Center, School of Basic Medicine, Air Force Medical University (Fourth Military Medical University), Xi'an, 710032, China.
- State Key Laboratory of Military Stomatology, School of Stomatology, Air Force Medical University (Fourth Military Medical University), Xi'an, China.
| | - Hui Liu
- National Teaching Demonstration Center, School of Basic Medicine, Air Force Medical University (Fourth Military Medical University), Xi'an, 710032, China
- Department of Human Anatomy, Histology and Embryology, Medical School of Yan'an University, Yan'an, China
| | - Shu-Jiao Li
- National Teaching Demonstration Center, School of Basic Medicine, Air Force Medical University (Fourth Military Medical University), Xi'an, 710032, China
| | - Ban Feng
- National Teaching Demonstration Center, School of Basic Medicine, Air Force Medical University (Fourth Military Medical University), Xi'an, 710032, China
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Disease & Shaanxi Engineering Research Center for Dental Material and Advanced Manufacture, Department of Pharmacy, Air Force Medical University (Fourth Military Medical University), Xi'an, China
| | - Yun-Qiang Huang
- National Teaching Demonstration Center, School of Basic Medicine, Air Force Medical University (Fourth Military Medical University), Xi'an, 710032, China
| | - Shui-Bing Liu
- Department of Pharmacology, School of Pharmacy, Air Force Medical University (Fourth Military Medical University), Xi'an, 710032, China.
| | - Yan-Ling Yang
- Department of Hepatobiliary Surgery, Xijing Hospital, Air Force Medical University (Fourth Military Medical University), Xi'an, 710032, China.
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Ruck L, Wiegand S, Kühnen P. Relevance and consequence of chronic inflammation for obesity development. Mol Cell Pediatr 2023; 10:16. [PMID: 37957462 PMCID: PMC10643747 DOI: 10.1186/s40348-023-00170-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023] Open
Abstract
BACKGROUND Increasing prevalence of morbid obesity accompanied by comorbidities like type 2 diabetes mellitus (T2DM) led to a demand for improving therapeutic strategies and pharmacological intervention options. Apart from genetics, inflammation processes have been hypothesized to be of importance for the development of obesity and related aspects like insulin resistance. MAIN TEXT Within this review, we provide an overview of the intricate interplay between chronic inflammation of the adipose tissue and the hypothalamus and the development of obesity. Further understanding of this relationship might improve the understanding of the underlying mechanism and may be of relevance for the establishment of new treatment strategies.
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Affiliation(s)
- Lisa Ruck
- Klinik Für Pädiatrische Endokrinologie und Diabetologie, Charité Universitätsmedizin, Berlin, Germany.
- Berlin Institute of Health at Charité-Universitätsmedizin Berlin, BIH Biomedical Innovation Academy, BIH Charité Junior Clinician Scientist Program, Charitéplatz 1, 10117, Berlin, Germany.
| | - Susanna Wiegand
- Abteilung Interdisziplinär, Sozial-Pädiatrisches Zentrum, Charité Universitätsmedizin, Berlin, Germany
| | - Peter Kühnen
- Klinik Für Pädiatrische Endokrinologie und Diabetologie, Charité Universitätsmedizin, Berlin, Germany
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Kutsche HS, Schreckenberg R, Schlüter KD. Uncoupling Proteins in Striated Muscle Tissue: Known Facts and Open Questions. Antioxid Redox Signal 2022; 37:324-335. [PMID: 35044239 DOI: 10.1089/ars.2021.0258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Significance: Uncoupling proteins (UCPs) are a family of proteins that allow proton leakage across the inner mitochondrial membrane. Although UCP1, also known as thermogenin, is well known and important for heat generation in brown adipose tissue, striated muscles express two distinct members of UCP, namely UCP2 and UCP3. Unlike UCP1, the main function of UCP2 and UCP3 does not appear to be heat production. Recent Advances: Interestingly, UCP2 is the main isoform expressed in cardiac tissues, whereas UCP3 is the dominant isoform in skeletal muscles. In the past years, researchers have started to investigate the regulation of UCP2 and UCP3 expression in striated muscles. Furthermore, concepts about the proposed functions of UCP2 and UCP3 in striated muscles are developed but are still a matter of debate. Critical Issues: Potential functions of UCP2 and UCP3 in striated muscles include a role in protection against mitochondria-dependent oxidative stress, as transporter for pyruvate, fatty acids, and protons into and out of the mitochondria, and in metabolic sensing. In this context, the different isoform expression of UCP2 and UCP3 in the skeletal and cardiac muscle may be related to different metabolic requirements of the two organs. Future Directions: The level of expression of UCP2 and UCP3 in striated muscles changes in different disease stages. This suggests that UCPs may become drug targets for therapy in the future. Antioxid. Redox Signal. 37, 324-335.
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Affiliation(s)
| | - Rolf Schreckenberg
- Institute of Physiology, Justus-Liebig University Giessen, Giessen, Germany
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Križančić Bombek L, Čater M. Skeletal Muscle Uncoupling Proteins in Mice Models of Obesity. Metabolites 2022; 12:metabo12030259. [PMID: 35323702 PMCID: PMC8955650 DOI: 10.3390/metabo12030259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/01/2022] [Accepted: 03/15/2022] [Indexed: 02/05/2023] Open
Abstract
Obesity and accompanying type 2 diabetes are among major and increasing worldwide problems that occur fundamentally due to excessive energy intake during its expenditure. Endotherms continuously consume a certain amount of energy to maintain core body temperature via thermogenic processes, mainly in brown adipose tissue and skeletal muscle. Skeletal muscle glucose utilization and heat production are significant and directly linked to body glucose homeostasis at rest, and especially during physical activity. However, this glucose balance is impaired in diabetic and obese states in humans and mice, and manifests as glucose resistance and altered muscle cell metabolism. Uncoupling proteins have a significant role in converting electrochemical energy into thermal energy without ATP generation. Different homologs of uncoupling proteins were identified, and their roles were linked to antioxidative activity and boosting glucose and lipid metabolism. From this perspective, uncoupling proteins were studied in correlation to the pathogenesis of diabetes and obesity and their possible treatments. Mice were extensively used as model organisms to study the physiology and pathophysiology of energy homeostasis. However, we should be aware of interstrain differences in mice models of obesity regarding thermogenesis and insulin resistance in skeletal muscles. Therefore, in this review, we gathered up-to-date knowledge on skeletal muscle uncoupling proteins and their effect on insulin sensitivity in mouse models of obesity and diabetes.
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Mitochondrial Uncoupling Proteins (UCPs) as Key Modulators of ROS Homeostasis: A Crosstalk between Diabesity and Male Infertility? Antioxidants (Basel) 2021; 10:antiox10111746. [PMID: 34829617 PMCID: PMC8614977 DOI: 10.3390/antiox10111746] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/27/2021] [Accepted: 10/28/2021] [Indexed: 12/14/2022] Open
Abstract
Uncoupling proteins (UCPs) are transmembrane proteins members of the mitochondrial anion transporter family present in the mitochondrial inner membrane. Currently, six homologs have been identified (UCP1-6) in mammals, with ubiquitous tissue distribution and multiple physiological functions. UCPs are regulators of key events for cellular bioenergetic metabolism, such as membrane potential, metabolic efficiency, and energy dissipation also functioning as pivotal modulators of ROS production and general cellular redox state. UCPs can act as proton channels, leading to proton re-entry the mitochondrial matrix from the intermembrane space and thus collapsing the proton gradient and decreasing the membrane potential. Each homolog exhibits its specific functions, from thermogenesis to regulation of ROS production. The expression and function of UCPs are intimately linked to diabesity, with their dysregulation/dysfunction not only associated to diabesity onset, but also by exacerbating oxidative stress-related damage. Male infertility is one of the most overlooked diabesity-related comorbidities, where high oxidative stress takes a major role. In this review, we discuss in detail the expression and function of the different UCP homologs. In addition, the role of UCPs as key regulators of ROS production and redox homeostasis, as well as their influence on the pathophysiology of diabesity and potential role on diabesity-induced male infertility is debated.
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Barreto P, Couñago RM, Arruda P. Mitochondrial uncoupling protein-dependent signaling in plant bioenergetics and stress response. Mitochondrion 2020; 53:109-120. [DOI: 10.1016/j.mito.2020.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 04/06/2020] [Accepted: 05/14/2020] [Indexed: 12/15/2022]
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Esfandiary A, Kutsche HS, Schreckenberg R, Weber M, Pak O, Kojonazarov B, Sydykov A, Hirschhäuser C, Wolf A, Haag D, Hecker M, Fink L, Seeger W, Ghofrani HA, Schermuly RT, Weißmann N, Schulz R, Rohrbach S, Li L, Sommer N, Schlüter KD. Protection against pressure overload-induced right heart failure by uncoupling protein 2 silencing. Cardiovasc Res 2020; 115:1217-1227. [PMID: 30850841 PMCID: PMC6529920 DOI: 10.1093/cvr/cvz049] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/31/2019] [Accepted: 03/06/2019] [Indexed: 12/14/2022] Open
Abstract
Aims The role of uncoupling protein 2 (UCP2) in cardiac adaptation to pressure overload remains unclear. In a classical model of left ventricular pressure overload genetic deletion of UCP2 (UCP2−/−) protected against cardiac hypertrophy and failure. However, in UCP2−/− mice increased proliferation of pulmonary arterial smooth muscle cells induces mild pulmonary hypertension, right ventricular (RV) hypertrophy, and reduced cardiac output. This suggests a different role for UCP2 in RV and left ventricular adaptation to pressure overload. To clarify this situation in more detail UCP2−/− and wild-type mice were exposed to pulmonary arterial banding (PAB). Methods and results Mice were analysed (haemodynamics, morphometry, and echocardiography) 3 weeks after PAB or sham surgery. Myocytes and non-myocytes were isolated and analysed separately. Cell shortening of myocytes and fura-2 loading of cardiomyocytes were used to characterize their function. Brd assay was performed to study fibroblast proliferation. Isolated mitochondria were analysed to investigate the role of UCP2 for reactive oxygen species (ROS) production. UCP2 mRNA was 2.7-fold stronger expressed in RV myocytes than in left ventricular myocytes and stronger expressed in non-myocytes compared with myocytes. Three weeks after PAB, cardiac output was reduced in wild type but preserved in UCP2−/− mice. UCP2−/− had increased RV wall thickness, but lower RV internal diameters and displayed a significant stronger fibrosis. Cardiac fibroblasts from UCP2−/− had reduced proliferation rates but higher collagen-1 expression. Myocytes isolated from mice after PAB banding showed preserved function that was further improved by UCP2−/−. Mitochondrial ROS production and respiration was similar between UCP2−/− or wild-type hearts. Conclusion Despite a mild pulmonary hypertension in UCP2−/− mice, hearts from these mice are well preserved against additional pressure overload (severe pulmonary hypertension). This—at least in part—depends on different behaviour of non-myocytes (fibroblasts).
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Affiliation(s)
| | - Hanna S Kutsche
- Department of Physiology, Justus-Liebig University Gießen, Aulweg 129, Gießen, Germany
| | - Rolf Schreckenberg
- Department of Physiology, Justus-Liebig University Gießen, Aulweg 129, Gießen, Germany
| | - Martin Weber
- Department of Physiology, Justus-Liebig University Gießen, Aulweg 129, Gießen, Germany
| | - Oleg Pak
- Justus-Liebig-University Gießen, ECCPS, Aulweg 130, Gießen, Germany
| | | | - Akylbek Sydykov
- Justus-Liebig-University Gießen, ECCPS, Aulweg 130, Gießen, Germany
| | | | - Annemarie Wolf
- Department of Physiology, Justus-Liebig University Gießen, Aulweg 129, Gießen, Germany
| | - Daniela Haag
- Justus-Liebig-University Gießen, ECCPS, Aulweg 130, Gießen, Germany
| | - Matthias Hecker
- Justus-Liebig-University Gießen, ECCPS, Aulweg 130, Gießen, Germany
| | - Ludger Fink
- Justus-Liebig-University Gießen, ECCPS, Aulweg 130, Gießen, Germany
| | - Werner Seeger
- Justus-Liebig-University Gießen, ECCPS, Aulweg 130, Gießen, Germany
| | | | | | - Norbert Weißmann
- Justus-Liebig-University Gießen, ECCPS, Aulweg 130, Gießen, Germany
| | - Rainer Schulz
- Department of Physiology, Justus-Liebig University Gießen, Aulweg 129, Gießen, Germany
| | - Susanne Rohrbach
- Department of Physiology, Justus-Liebig University Gießen, Aulweg 129, Gießen, Germany
| | - Ling Li
- Department of Physiology, Justus-Liebig University Gießen, Aulweg 129, Gießen, Germany
| | - Natascha Sommer
- Justus-Liebig-University Gießen, ECCPS, Aulweg 130, Gießen, Germany
| | - Klaus-Dieter Schlüter
- Department of Physiology, Justus-Liebig University Gießen, Aulweg 129, Gießen, Germany
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9
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Kutsche HS, Schreckenberg R, Weber M, Hirschhäuser C, Rohrbach S, Li L, Niemann B, Schulz R, Schlüter KD. Alterations in Glucose Metabolism During the Transition to Heart Failure: The Contribution of UCP-2. Cells 2020; 9:cells9030552. [PMID: 32120777 PMCID: PMC7140436 DOI: 10.3390/cells9030552] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 12/20/2022] Open
Abstract
The cardiac expression of the mitochondrial uncoupling protein (UCP)-2 is increased in patients with heart failure. However, the underlying causes as well as the possible consequences of these alterations during the transition from hypertrophy to heart failure are still unclear. To investigate the role of UCP-2 mechanistically, expression of UCP-2 was silenced by small interfering RNA in adult rat ventricular cardiomyocytes. We demonstrate that a downregulation of UCP-2 by siRNA in cardiomyocytes preserves contractile function in the presence of angiotensin II. Furthermore, silencing of UCP-2 was associated with an upregulation of glucose transporter type (Glut)-4, increased glucose uptake, and reduced intracellular lactate levels, indicating improvement of the oxidative glucose metabolism. To study this adaptation in vivo, spontaneously hypertensive rats served as a model for cardiac hypertrophy due to pressure overload. During compensatory hypertrophy, we found low UCP-2 levels with an upregulation of Glut-4, while the decompensatory state with impaired function was associated with an increase of UCP-2 and reduced Glut-4 expression. By blocking the aldosterone receptor with spironolactone, both cardiac function as well as UCP-2 and Glut-4 expression levels of the compensated phase could be preserved. Furthermore, we were able to confirm this by left ventricular (LV) biopsies of patients with end-stage heart failure. The results of this study show that UCP-2 seems to impact the cardiac glucose metabolism during the transition from hypertrophy to failure by affecting glucose uptake through Glut-4. We suggest that the failing heart could benefit from low UCP-2 levels by improving the efficiency of glucose oxidation. For this reason, UCP-2 inhibition might be a promising therapeutic strategy to prevent the development of heart failure.
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Affiliation(s)
- Hanna Sarah Kutsche
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (R.S.); (M.W.); (C.H.); (S.R.); (L.L.); (R.S.); (K.-D.S.)
- Correspondence: ; Tel.: +49-641-99-47145
| | - Rolf Schreckenberg
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (R.S.); (M.W.); (C.H.); (S.R.); (L.L.); (R.S.); (K.-D.S.)
| | - Martin Weber
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (R.S.); (M.W.); (C.H.); (S.R.); (L.L.); (R.S.); (K.-D.S.)
| | - Christine Hirschhäuser
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (R.S.); (M.W.); (C.H.); (S.R.); (L.L.); (R.S.); (K.-D.S.)
| | - Susanne Rohrbach
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (R.S.); (M.W.); (C.H.); (S.R.); (L.L.); (R.S.); (K.-D.S.)
| | - Ling Li
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (R.S.); (M.W.); (C.H.); (S.R.); (L.L.); (R.S.); (K.-D.S.)
| | - Bernd Niemann
- Universitätsklinikum Gießen, Klinik für Herz-, Kinderherz- und Gefäßchirurgie, 35392 Gießen, Germany;
| | - Rainer Schulz
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (R.S.); (M.W.); (C.H.); (S.R.); (L.L.); (R.S.); (K.-D.S.)
| | - Klaus-Dieter Schlüter
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (R.S.); (M.W.); (C.H.); (S.R.); (L.L.); (R.S.); (K.-D.S.)
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Pohl EE, Rupprecht A, Macher G, Hilse KE. Important Trends in UCP3 Investigation. Front Physiol 2019; 10:470. [PMID: 31133866 PMCID: PMC6524716 DOI: 10.3389/fphys.2019.00470] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 04/04/2019] [Indexed: 11/13/2022] Open
Abstract
Membrane uncoupling protein 3 (UCP3), a member of the mitochondrial uncoupling protein family, was discovered in 1997. UCP3's properties, such as its high homology to other mitochondrial carriers, especially to UCP2, its short lifetime and low specificity of UCP3 antibodies, have hindered progress in understanding its biological function and transport mechanism over decades. The abundance of UCP3 is highest in murine brown adipose tissue (BAT, 15.0 pmol/mg protein), compared to heart (2.7 pmol/mg protein) and the gastrocnemius muscle (1.7 pmol/mg protein), but it is still 400-fold lower than the abundance of UCP1, a biomarker for BAT. Investigation of UCP3 reconstituted in planar bilayer membranes revealed that it transports protons only when activated by fatty acids (FA). Although purine nucleotides (PN) inhibit UCP3-mediated transport, the molecular mechanism differs from that of UCP1. It remains a conundrum that two homologous proton-transporting proteins exist within the same tissue. Recently, we proposed that UCP3 abundance directly correlates with the degree of FA β-oxidation in cell metabolism. Further development in this field implies that UCP3 may have dual function in transporting substrates, which have yet to be identified, alongside protons. Evaluation of the literature with respect to UCP3 is a complex task because (i) UCP3 features are often extrapolated from its "twin" UCP2 without additional proof, and (ii) the specificity of antibodies against UCP3 used in studies is rarely evaluated. In this review, we primarily focus on recent findings obtained for UCP3 in biological and biomimetic systems.
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Affiliation(s)
- Elena E. Pohl
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Anne Rupprecht
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
- Institute of Pharmacology and Toxicology, Rostock University Medical Center, Rostock, Germany
| | - Gabriel Macher
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Karolina E. Hilse
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
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11
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Mendez-Romero O, Uribe-Carvajal S, Chiquete-Felix N, Muhlia-Almazan A. Mitochondrial uncoupling proteins UCP4 and UCP5 from the Pacific white shrimp Litopenaeus vannamei. J Bioenerg Biomembr 2019; 51:103-119. [PMID: 30796582 DOI: 10.1007/s10863-019-09789-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 02/10/2019] [Indexed: 01/21/2023]
Abstract
Mitochondrial uncoupling proteins (UCP) transport protons from the intermembrane space to the mitochondrial matrix uncoupling oxidative phosphorylation. In mammals, these proteins have been implicated in several cellular functions ranging from thermoregulation to antioxidant defense. In contrast, their invertebrate homologs have been much less studied despite the great diversity of species. In this study, two transcripts encoding mitochondrial uncoupling proteins were, for the first time, characterized in crustaceans. The white shrimp Litopenaeus vannamei transcript LvUCP4 is expressed in all tested shrimp tissues/organs, and its cDNA includes a coding region of 954 bp long which encodes a deduced protein 318 residues long and a predicted molecular weight of 35.3 kDa. The coding region of LvUCP5 transcript is 906 bp long, encodes a protein of 302 residues with a calculated molecular weight of 33.17 kDa. Both proteins share homology with insect UCPs, their predicted structures show the conserved motifs of the mitochondrial carrier proteins and were confirmed to be located in the mitochondria through a Western blot analysis. The genic expression of LvUCP4 and LvUCP5 was evaluated in shrimp at oxidative stress conditions and results were compared to some antioxidant enzymes to infer about their antioxidant role. LvUCP4 and LvUCP5 genes expression did not change during hypoxia/re-oxygenation, and no coordinated responses were detected with antioxidant enzymes at the transcriptional level. Results confirmed UCPs as the first uncoupling mechanism reported in this species, but their role in the oxidative stress response remains to be confirmed.
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Affiliation(s)
- Ofelia Mendez-Romero
- Bioenergetics and Molecular Genetics Lab, Centro de Investigacion en Alimentacion y Desarrollo, A. C. Carretera a Ejido La Victoria Km 0.6, PO Box 1735, 83000, Hermosillo, Sonora, Mexico
| | - Salvador Uribe-Carvajal
- Department of Molecular Genetics, Instituto de Fisiologia Celular, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, PO Box 70-242, Mexico City, Mexico
| | - Natalia Chiquete-Felix
- Department of Molecular Genetics, Instituto de Fisiologia Celular, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, PO Box 70-242, Mexico City, Mexico
| | - Adriana Muhlia-Almazan
- Bioenergetics and Molecular Genetics Lab, Centro de Investigacion en Alimentacion y Desarrollo, A. C. Carretera a Ejido La Victoria Km 0.6, PO Box 1735, 83000, Hermosillo, Sonora, Mexico.
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12
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Hough RF, Islam MN, Gusarova GA, Jin G, Das S, Bhattacharya J. Endothelial mitochondria determine rapid barrier failure in chemical lung injury. JCI Insight 2019; 4:124329. [PMID: 30728333 DOI: 10.1172/jci.insight.124329] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/20/2018] [Indexed: 12/14/2022] Open
Abstract
Acid aspiration, which can result from several etiologies, including postoperative complications, leads to direct contact of concentrated hydrochloric acid (HCl) with the alveolar epithelium. As a result, rapid endothelial activation induces alveolar inflammation, leading to life-threatening pulmonary edema. Because mechanisms underlying the rapid endothelial activation are not understood, here we determined responses in real time through optical imaging of alveoli of live mouse lungs. By alveolar micropuncture, we microinfused concentrated HCl in the alveolar lumen. As expected, acid contact with the epithelium caused rapid, but transient, apical injury. However, there was no concomitant membrane injury to the endothelium. Nevertheless, H2O2-mediated epithelial-endothelial paracrine signaling induced endothelial barrier failure, as detected by microvascular dextran leakage and lung water quantification. Remarkably, endothelial mitochondria regulated the barrier failure by activating uncoupling protein 2 (UCP2), thereby inducing transient mitochondrial depolarization that led to cofilin-induced actin depolymerization. Knockdown, or endothelium-targeted deletion of UCP2 expression, blocked these responses, including pulmonary edema. To our knowledge, these findings are the first to mechanistically implicate endothelial mitochondria in acid-induced barrier deterioration and pulmonary edema. We suggest endothelial UCP2 may be a therapeutic target for acid-induced acute lung injury.
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Affiliation(s)
- Rebecca F Hough
- Lung Biology Lab, Department of Medicine, and.,Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons, New York, New York, USA
| | | | | | | | - Shonit Das
- Lung Biology Lab, Department of Medicine, and
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13
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Mitochondrial unfolded protein response: a stress response with implications for fertility and reproductive aging. Fertil Steril 2019; 111:197-204. [DOI: 10.1016/j.fertnstert.2018.11.048] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 11/30/2018] [Indexed: 12/24/2022]
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14
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Christensen M, Schiffer TA, Gustafsson H, Krag SP, Nørregaard R, Palm F. Metformin attenuates renal medullary hypoxia in diabetic nephropathy through inhibition uncoupling protein-2. Diabetes Metab Res Rev 2019; 35:e3091. [PMID: 30345618 DOI: 10.1002/dmrr.3091] [Citation(s) in RCA: 14] [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: 05/07/2018] [Revised: 10/03/2018] [Accepted: 10/16/2018] [Indexed: 11/09/2022]
Abstract
BACKGROUND The purpose of the study is to examine the effect of metformin on oxygen metabolism and mitochondrial function in the kidney of an animal model of insulinopenic diabetes in order to isolate any renoprotective effect from any concomitant effect on blood glucose homeostasis. METHODS Sprague-Dawley rats were injected with streptozotocin (STZ) (50 mg kg-1 ) and when stable started on metformin treatment (250 mg kg-1 ) in the drinking water. Rats were prepared for in vivo measurements 25 to 30 days after STZ injection, where renal function, including glomerular filtration rate and sodium transport, was estimated in anesthetized rats. Intrarenal oxygen tension was measured using oxygen sensors. Furthermore, mitochondrial function was assessed in mitochondria isolated from kidney cortex and medulla analysed by high-resolution respirometry, and superoxide production was evaluated using electron paramagnetic resonance. RESULTS Insulinopenic rats chronically treated with metformin for 4 weeks displayed improved medullary tissue oxygen tension despite of no effect of metformin on blood glucose homeostasis. Metformin reduced UCP2-dependent LEAK and differentially affected medullary mitochondrial superoxide radical production in control and diabetic rats. CONCLUSIONS Metformin attenuates diabetes-induced renal medullary tissue hypoxia in an animal model of insulinopenic type 1 diabetes. The results suggest that the mechanistic pathway to attenuate the diabetes-induced medullary hypoxia is independent of blood glucose homeostasis and includes reduced UCP2-mediated mitochondrial proton LEAK.
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Affiliation(s)
| | - Tomas A Schiffer
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Håkan Gustafsson
- Department of Radiology Norrköping and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | | | - Rikke Nørregaard
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Fredrik Palm
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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15
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Molecular evolution of uncoupling proteins and implications for brain function. Neurosci Lett 2018; 696:140-145. [PMID: 30582970 DOI: 10.1016/j.neulet.2018.12.027] [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] [Received: 11/09/2018] [Revised: 12/17/2018] [Accepted: 12/18/2018] [Indexed: 01/01/2023]
Abstract
Uncoupling proteins (UCPs) belong to the mitochondrial anion carrier superfamily and catalyze important metabolic functions at the mitochondrial inner membrane. While the thermogenic role of UCP1 in brown fat of eutherian mammals is well established, the molecular functions of UCP1 in ectothermic vertebrates and of other UCP paralogs remain less clear. Here, we critically discuss the existence of brain UCPs and their potential roles. Applying phylogenetic classification of novel UCPs, we summarize the evidence for brain UCP1 among vertebrates, the role of UCP2 in specific brain areas, and the existence of brain-specific UCPs. The phylogenetic analyses and discussion on functional data should alert the scientific community that the molecular function of so-called UCP1 homologues is by far not clarified and possibly relates to neither thermogenesis nor mitochondrial uncoupling.
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16
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Ježek P, Holendová B, Garlid KD, Jabůrek M. Mitochondrial Uncoupling Proteins: Subtle Regulators of Cellular Redox Signaling. Antioxid Redox Signal 2018; 29:667-714. [PMID: 29351723 PMCID: PMC6071544 DOI: 10.1089/ars.2017.7225] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Mitochondria are the energetic, metabolic, redox, and information signaling centers of the cell. Substrate pressure, mitochondrial network dynamics, and cristae morphology state are integrated by the protonmotive force Δp or its potential component, ΔΨ, which are attenuated by proton backflux into the matrix, termed uncoupling. The mitochondrial uncoupling proteins (UCP1-5) play an eminent role in the regulation of each of the mentioned aspects, being involved in numerous physiological events including redox signaling. Recent Advances: UCP2 structure, including purine nucleotide and fatty acid (FA) binding sites, strongly support the FA cycling mechanism: UCP2 expels FA anions, whereas uncoupling is achieved by the membrane backflux of protonated FA. Nascent FAs, cleaved by phospholipases, are preferential. The resulting Δp dissipation decreases superoxide formation dependent on Δp. UCP-mediated antioxidant protection and its impairment are expected to play a major role in cell physiology and pathology. Moreover, UCP2-mediated aspartate, oxaloacetate, and malate antiport with phosphate is expected to alter metabolism of cancer cells. CRITICAL ISSUES A wide range of UCP antioxidant effects and participations in redox signaling have been reported; however, mechanisms of UCP activation are still debated. Switching off/on the UCP2 protonophoretic function might serve as redox signaling either by employing/releasing the extra capacity of cell antioxidant systems or by directly increasing/decreasing mitochondrial superoxide sources. Rapid UCP2 degradation, FA levels, elevation of purine nucleotides, decreased Mg2+, or increased pyruvate accumulation may initiate UCP-mediated redox signaling. FUTURE DIRECTIONS Issues such as UCP2 participation in glucose sensing, neuronal (synaptic) function, and immune cell activation should be elucidated. Antioxid. Redox Signal. 29, 667-714.
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Affiliation(s)
- Petr Ježek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Blanka Holendová
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Keith D Garlid
- 2 UCLA Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA , Los Angeles, California
| | - Martin Jabůrek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
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17
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Lin J, Cao C, Tao C, Ye R, Dong M, Zheng Q, Wang C, Jiang X, Qin G, Yan C, Li K, Speakman JR, Wang Y, Jin W, Zhao J. Cold adaptation in pigs depends on UCP3 in beige adipocytes. J Mol Cell Biol 2018; 9:364-375. [PMID: 28486585 DOI: 10.1093/jmcb/mjx018] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 05/07/2017] [Indexed: 12/27/2022] Open
Abstract
Pigs lack functional uncoupling protein 1 (UCP1) making them susceptible to cold. Nevertheless, several pig breeds are known to be cold resistant. The molecular mechanism(s) enabling such adaptation are currently unknown. Here, we show that this resistance is not dependent on shivering, but rather depends on UCP3 and white adipose tissue (WAT) browning. In two cold-resistant breeds (Tibetan and Min), but not a cold-sensitive breed (Bama), WAT browning was induced after cold exposure. Beige adipocytes from Tibetan pigs exhibited greater oxidative capacity than those from Bama pigs. Notably, UCP3 expression was significantly increased only in cold-resistant breeds, and knockdown of UCP3 expression in Tibetan adipocytes phenocopied Bama adipocytes in culture. Moreover, the eight dominant pig breeds found across China can be classified into cold-sensitive and cold-resistant breeds based on the UCP3 cDNA sequence. This study indicates that UCP3 has contributed to the evolution of cold resistance in the pig and overturns the orthodoxy that UCP1 is the only thermogenic uncoupling protein.
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Affiliation(s)
- Jun Lin
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Chunwei Cao
- State Key Laboratory of Stem Cell and Reproductive Biology, Chinese Academy of Sciences, Beijing, China
| | - Cong Tao
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Rongcai Ye
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Meng Dong
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Qiantao Zheng
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Stem Cell and Reproductive Biology, Chinese Academy of Sciences, Beijing, China
| | - Chao Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaoxiao Jiang
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Guosong Qin
- State Key Laboratory of Stem Cell and Reproductive Biology, Chinese Academy of Sciences, Beijing, China
| | - Changguo Yan
- Department of Animal Science, Yanbian University, Yanji, China
| | - Kui Li
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - John R Speakman
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Yanfang Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wanzhu Jin
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Jianguo Zhao
- State Key Laboratory of Stem Cell and Reproductive Biology, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
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18
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Chen K, Xu Z, Liu Y, Wang Z, Li Y, Xu X, Chen C, Xia T, Liao Q, Yao Y, Zeng C, He D, Yang Y, Tan T, Yi J, Zhou J, Zhu H, Ma J, Zeng C. Irisin protects mitochondria function during pulmonary ischemia/reperfusion injury. Sci Transl Med 2018; 9:9/418/eaao6298. [PMID: 29187642 DOI: 10.1126/scitranslmed.aao6298] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 08/10/2017] [Accepted: 10/20/2017] [Indexed: 12/13/2022]
Abstract
Limb remote ischemic preconditioning (RIPC) is an effective means of protection against ischemia/reperfusion (IR)-induced injury to multiple organs. Many studies are focused on identifying endocrine mechanisms that underlie the cross-talk between muscle and RIPC-mediated organ protection. We report that RIPC releases irisin, a myokine derived from the extracellular portion of fibronectin domain-containing 5 protein (FNDC5) in skeletal muscle, to protect against injury to the lung. Human patients with neonatal respiratory distress syndrome show reduced concentrations of irisin in the serum and increased irisin concentrations in the bronchoalveolar lavage fluid, suggesting transfer of irisin from circulation to the lung under physiologic stress. In mice, application of brief periods of ischemia preconditioning stimulates release of irisin into circulation and transfer of irisin to the lung subjected to IR injury. Irisin, via lipid raft-mediated endocytosis, enters alveolar cells and targets mitochondria. Interaction between irisin and mitochondrial uncoupling protein 2 (UCP2) allows for prevention of IR-induced oxidative stress and preservation of mitochondrial function. Animal model studies show that intravenous administration of exogenous irisin protects against IR-induced injury to the lung via improvement of mitochondrial function, whereas in UCP2-deficient mice or in the presence of a UCP2 inhibitor, the protective effect of irisin is compromised. These results demonstrate that irisin is a myokine that facilitates RIPC-mediated lung protection. Targeting the action of irisin in mitochondria presents a potential therapeutic intervention for pulmonary IR injury.
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Affiliation(s)
- Ken Chen
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China.,Department of Cardiology, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Zaicheng Xu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Yukai Liu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Zhen Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Yu Li
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Xuefei Xu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Caiyu Chen
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Tianyang Xia
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Qiao Liao
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Yonggang Yao
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Cindy Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Duofen He
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Yongjian Yang
- Department of Cardiology, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Tao Tan
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Jianxun Yi
- Department of Physiology, Kansas City University, Kansas City, MO 64106, USA
| | - Jingsong Zhou
- Department of Physiology, Kansas City University, Kansas City, MO 64106, USA
| | - Hua Zhu
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Jianjie Ma
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China. .,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
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19
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Hilse KE, Rupprecht A, Egerbacher M, Bardakji S, Zimmermann L, Wulczyn AEMS, Pohl EE. The Expression of Uncoupling Protein 3 Coincides With the Fatty Acid Oxidation Type of Metabolism in Adult Murine Heart. Front Physiol 2018; 9:747. [PMID: 29988383 PMCID: PMC6024016 DOI: 10.3389/fphys.2018.00747] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 05/28/2018] [Indexed: 01/07/2023] Open
Abstract
The involvement of mitochondrial uncoupling proteins 2 and 3 in the pathogenesis of cardiovascular diseases is widely acknowledged. However, contradictory reports show that the functions of UCP2/UCP3 are still disputed. We have previously described that UCP2 is highly abundant in cells that rely on glycolysis, such as stem, cancer and activated immune cells. In contrast, high amounts of UCP3 are present in brown adipose tissue, followed by heart and skeletal muscles - all known to metabolize fatty acids (FA) to a high extent. Using two different models - mouse embryonic stem cell (mESC) differentiation to cardiomyocytes (CM) and murine heart at different developmental stages - we now tested the concept that the expression ratio between UCP2 and UCP3 indicates the metabolism type in CM. Our results revealed the tight correlation between UCP3 abundance, expression of mitochondrial fatty acid oxidation (FAO) markers and presence of multiple connections between mitochondria and lipid droplets. We further demonstrated that the time course of UCP3 expression neither coincided with the onset of the electrical activity in CM, derived from mESC, nor with the expression of respiratory chain proteins, the observation which rendered protein participation in ROS regulation unlikely. The present data imply that UCP3 may facilitate FAO by transporting FAs into mitochondria. In contrast, UCP2 was highly abundant at early stages of heart development and in mESC. Understanding, that the expression patterns of UCP3 and UCP2 in heart during development reflect the type of the cell metabolism is key to the uncovering their different functions. Their expression ratio may be an important diagnostic criterion for the degree of CM differentiation and/or severity of a heart failure.
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Affiliation(s)
- Karolina E Hilse
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Anne Rupprecht
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Monika Egerbacher
- Histology and Embryology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Sarah Bardakji
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Lars Zimmermann
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Andrea E M Seiler Wulczyn
- German Centre for the Protection of Laboratory Animals (Bf3R), Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Elena E Pohl
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Vienna, Austria
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20
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Dias C, Lourenço CF, Barbosa RM, Laranjinha J, Ledo A. Analysis of respiratory capacity in brain tissue preparations: high-resolution respirometry for intact hippocampal slices. Anal Biochem 2018; 551:43-50. [PMID: 29753719 DOI: 10.1016/j.ab.2018.05.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/02/2018] [Accepted: 05/10/2018] [Indexed: 12/13/2022]
Abstract
The evaluation of mitochondrial function provides the basis for the study of brain bioenergetics. However, analysis of brain mitochondrial respiration has been hindered by the low yield associated with mitochondria isolation procedures. Furthermore, isolating mitochondria or cells results in loss of the inherent complexity of the central nervous system. High-resolution respirometry (HRR), is a valuable tool to study mitochondrial function and has been used in diverse biological preparations ranging from isolated mitochondria to tissue homogenates and permeabilized tissue biopsies. Here we describe a novel methodology for evaluation of mitochondrial respiration using tissue preparations from the central nervous system, namely acute hippocampal slices from rodents, with HRR. By using acute intact hippocampal slices, tissue cytoarchitecture, intercellular communication and connectivity are preserved. Mitochondrial respiration was evaluated by using an adapted substrate-uncoupler-inhibitor titration (SUIT) protocol and the expected responses were observed. This methodology can be used to detect differences in mitochondrial function at the oxidative phosphorylation level and for studies with different brain oxidative substrates in physiological and neuropathological settings, by using a system that better represents the in vivo conditions than isolated mitochondria and/or cells.
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Affiliation(s)
- Cândida Dias
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
| | - Cátia F Lourenço
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
| | - Rui M Barbosa
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Portugal
| | - João Laranjinha
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Portugal
| | - Ana Ledo
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal.
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21
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Gaignard P, Liere P, Thérond P, Schumacher M, Slama A, Guennoun R. Role of Sex Hormones on Brain Mitochondrial Function, with Special Reference to Aging and Neurodegenerative Diseases. Front Aging Neurosci 2017; 9:406. [PMID: 29270123 PMCID: PMC5725410 DOI: 10.3389/fnagi.2017.00406] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 11/24/2017] [Indexed: 01/18/2023] Open
Abstract
The mitochondria have a fundamental role in both cellular energy supply and oxidative stress regulation and are target of the effects of sex steroids, particularly the neuroprotective ones. Aging is associated with a decline in the levels of different steroid hormones, and this decrease may underline some neural dysfunctions. Besides, modifications in mitochondrial functions associated with aging processes are also well documented. In this review, we will discuss studies that describe the modifications of brain mitochondrial function and of steroid levels associated with physiological aging and with neurodegenerative diseases. A special emphasis will be placed on describing and discussing our recent findings concerning the concomitant study of mitochondrial function (oxidative phosphorylation, oxidative stress) and brain steroid levels in both young (3-month-old) and aged (20-month-old) male and female mice.
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Affiliation(s)
- Pauline Gaignard
- U1195 Inserm and University Paris-Sud and University Paris-Saclay, Le Kremlin-Bicêtre, France
- Biochemistry Laboratory, Bicêtre Hospital, Assistance Publique-Hôpitaux de Paris, Le Kremlin-Bicêtre, France
| | - Philippe Liere
- U1195 Inserm and University Paris-Sud and University Paris-Saclay, Le Kremlin-Bicêtre, France
| | - Patrice Thérond
- Biochemistry Laboratory, Bicêtre Hospital, Assistance Publique-Hôpitaux de Paris, Le Kremlin-Bicêtre, France
| | - Michael Schumacher
- U1195 Inserm and University Paris-Sud and University Paris-Saclay, Le Kremlin-Bicêtre, France
| | - Abdelhamid Slama
- Biochemistry Laboratory, Bicêtre Hospital, Assistance Publique-Hôpitaux de Paris, Le Kremlin-Bicêtre, France
| | - Rachida Guennoun
- U1195 Inserm and University Paris-Sud and University Paris-Saclay, Le Kremlin-Bicêtre, France
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22
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Pan HC, Lee CC, Chou KM, Lu SC, Sun CY. Serum levels of uncoupling proteins in patients with differential insulin resistance: A community-based cohort study. Medicine (Baltimore) 2017; 96:e8053. [PMID: 28984759 PMCID: PMC5737995 DOI: 10.1097/md.0000000000008053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The uncoupling protein (UCP) belongs to a family of energy-dissipating proteins in mitochondria. Increasing evidences have indicated that UCPs have immense impact on glucose homeostasis and are key proteins in metabolic syndrome. For applying the findings to clinical practice, we designed a study to explore the association between serum UCPs 1-3 and insulin resistance. This investigation prospectively recorded demographical parameter and collected blood samples of 1071 participants from 4 districts in Northeastern Taiwan during the period from August 2013 to July 2014. Propensity score matching by age and sex in patients with top and bottom third homeostasis model assessment of insulin resistance (HOMA-IR) levels was performed, and 326 subjects were enrolled for further studies. The mean age of the patients was 59.4 years and the majority of them (65.5%) were females. The prevalence of metabolic syndrome was 35.5%. Our results demonstrated that serum UCPs 1-3 were significantly associated with differences in HOMA-IR levels. Multiple logistic regression analysis indicated that low UCP 1 and features of metabolic syndrome, namely hypertension, diabetes, body mass index, and high-density lipoprotein, were independent determinants for high HOMA-IR levels. We thus determined that low serum UCP 1 is a predictor for high resistance to insulin.
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Affiliation(s)
- Heng-Chih Pan
- Division of Nephrology, Department of Internal Medicine, Chang Gung Memorial Hospital, Keelung
- Community Medicine Research Center, Chang Gung Memorial Hospital, Keelung, Taiwan
| | - Chin-Chan Lee
- Division of Nephrology, Department of Internal Medicine, Chang Gung Memorial Hospital, Keelung
- School of Medicine, Chang Gung University, Taoyuan
- Community Medicine Research Center, Chang Gung Memorial Hospital, Keelung, Taiwan
| | - Kuei-Mei Chou
- Divisions of Endocrinology and Metabolism, Department of Internal Medicine
| | - Shang-Chieh Lu
- Division of Nephrology, Department of Internal Medicine, Chang Gung Memorial Hospital, Keelung
- Community Medicine Research Center, Chang Gung Memorial Hospital, Keelung, Taiwan
| | - Chiao-Yin Sun
- Division of Nephrology, Department of Internal Medicine, Chang Gung Memorial Hospital, Keelung
- School of Medicine, Chang Gung University, Taoyuan
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23
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The Slo(w) path to identifying the mitochondrial channels responsible for ischemic protection. Biochem J 2017; 474:2067-2094. [PMID: 28600454 DOI: 10.1042/bcj20160623] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/10/2017] [Accepted: 02/13/2017] [Indexed: 12/19/2022]
Abstract
Mitochondria play an important role in tissue ischemia and reperfusion (IR) injury, with energetic failure and the opening of the mitochondrial permeability transition pore being the major causes of IR-induced cell death. Thus, mitochondria are an appropriate focus for strategies to protect against IR injury. Two widely studied paradigms of IR protection, particularly in the field of cardiac IR, are ischemic preconditioning (IPC) and volatile anesthetic preconditioning (APC). While the molecular mechanisms recruited by these protective paradigms are not fully elucidated, a commonality is the involvement of mitochondrial K+ channel opening. In the case of IPC, research has focused on a mitochondrial ATP-sensitive K+ channel (mitoKATP), but, despite recent progress, the molecular identity of this channel remains a subject of contention. In the case of APC, early research suggested the existence of a mitochondrial large-conductance K+ (BK, big conductance of potassium) channel encoded by the Kcnma1 gene, although more recent work has shown that the channel that underlies APC is in fact encoded by Kcnt2 In this review, we discuss both the pharmacologic and genetic evidence for the existence and identity of mitochondrial K+ channels, and the role of these channels both in IR protection and in regulating normal mitochondrial function.
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24
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Picklo MJ, Johnson L, Idso J. PPAR mRNA Levels Are Modified by Dietary n-3 Fatty Acid Restriction and Energy Restriction in the Brain and Liver of Growing Rats. J Nutr 2017; 147:161-169. [PMID: 27927977 DOI: 10.3945/jn.116.237107] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/07/2016] [Accepted: 11/15/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Without dietary sources of n-3 (ω-3) long-chain polyunsaturated fatty acids (LCPUFAs), α-linolenic acid (ALA; 18:3n-3) is the precursor for docosahexaenoic acid (DHA; 22:6n-3). It is not known how energy restriction (ER) affects ALA conversion to DHA. OBJECTIVE We tested the hypothesis that ER reduces n-3 LCPUFA concentrations in tissues of growing rats fed diets replete with and deficient in ALA. METHODS Male Sprague-Dawley rats (23 d old) were provided AIN93G diets (4 wk) made with soybean oil (SO; ALA sufficient) or corn oil (CO; ALA deficient) providing 16% of energy as fat. For each dietary oil, ER rats were individually pair-fed 75% of another rat's ad libitum (AL) intake. Fatty acid (FA) concentrations in brain regions, liver, and plasma were analyzed. Expression of peroxisome proliferator-activated receptors (PPARs), uncoupling proteins (UCPs), and mitochondrial DNA was analyzed in the brain and liver. RESULTS AL rats consuming CO had a 65% lower concentration of n-3 docosapentaenoic acid (22:5n-3) and a 10% lower DHA concentration in the cerebral cortex and cerebellum than did the SO-AL group. ER did not alter cerebral n-3 LCPUFA status. Liver n-3 LCPUFA concentrations were reduced in rats fed CO compared with SO. ER reduced hepatic linoleic acid (18:2n-6), ALA, and arachidonic acid (20:4n-6) regardless of oil. ER and n-3 FA deficiency had independent effects on the mRNA levels of Pparα, Pparβ/δ, and Pparγ in the liver, cerebral cortex, and cerebellum. ER reduced Ucp3 mRNA by nearly 50% in the cerebral cortex, cerebellum, and liver, and Ucp5 mRNA was 30% lower in the cerebellum of rats receiving the CO diet. CONCLUSIONS Small perturbations in PUFA concentration and ER modify the mRNA levels of Ppar and Ucp in the juvenile rat brain. More research is needed to identify the long-term physiologic and behavioral impacts of ER and PUFA restriction in the juvenile brain.
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Affiliation(s)
- Matthew J Picklo
- USDA Agricultural Research Service Grand Forks Human Nutrition Research Center, Grand Forks, ND
| | - LuAnn Johnson
- USDA Agricultural Research Service Grand Forks Human Nutrition Research Center, Grand Forks, ND
| | - Joseph Idso
- USDA Agricultural Research Service Grand Forks Human Nutrition Research Center, Grand Forks, ND
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Uncoupling proteins of invertebrates: A review. IUBMB Life 2016; 68:691-9. [DOI: 10.1002/iub.1535] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 06/18/2016] [Indexed: 01/05/2023]
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Motloch LJ, Gebing T, Reda S, Schwaiger A, Wolny M, Hoppe UC. UCP3 Regulates Single-Channel Activity of the Cardiac mCa1. J Membr Biol 2016; 249:577-84. [PMID: 27371160 PMCID: PMC4942494 DOI: 10.1007/s00232-016-9913-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 06/15/2016] [Indexed: 12/14/2022]
Abstract
Mitochondrial Ca(2+) uptake (mCa(2+) uptake) is thought to be mediated by the mitochondrial Ca(2+) uniporter (MCU). UCP2 and UCP3 belong to a superfamily of mitochondrial ion transporters. Both proteins are expressed in the inner mitochondrial membrane of the heart. Recently, UCP2 was reported to modulate the function of the cardiac MCU related channel mCa1. However, the possible role of UCP3 in modulating cardiac mCa(2+) uptake via the MCU remains inconclusive. To understand the role of UCP3, we analyzed cardiac mCa1 single-channel activity in mitoplast-attached single-channel recordings from isolated murine cardiac mitoplasts, from adult wild-type controls (WT), and from UCP3 knockout mice (UCP3(-/-)). Single-channel registrations in UCP3(-/-) confirmed a murine voltage-gated Ca(2+) channel, i.e., mCa1, which was inhibited by Ru360. Compared to WT, mCa1 in UCP3(-/-) revealed similar single-channel characteristics. However, in UCP3(-/-) the channel exhibited decreased single-channel activity, which was insensitive to adenosine triphosphate (ATP) inhibition. Our results suggest that beyond UCP2, UCP3 also exhibits regulatory effects on cardiac mCa1/MCU function. Furthermore, we speculate that UCP3 might modulate previously described inhibitory effects of ATP on mCa1/MCU activity as well.
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Affiliation(s)
- Lukas J Motloch
- Department of Internal Medicine II, Paracelsus Medical University, Muellner Hauptstr. 48, A-5020, Salzburg, Austria.
| | - Tina Gebing
- Department of Internal Medicine II, Paracelsus Medical University, Muellner Hauptstr. 48, A-5020, Salzburg, Austria
| | - Sara Reda
- Department of Internal Medicine II, Paracelsus Medical University, Muellner Hauptstr. 48, A-5020, Salzburg, Austria
| | - Astrid Schwaiger
- Department of Internal Medicine II, Paracelsus Medical University, Muellner Hauptstr. 48, A-5020, Salzburg, Austria
| | - Martin Wolny
- Department of Internal Medicine II, Paracelsus Medical University, Muellner Hauptstr. 48, A-5020, Salzburg, Austria
| | - Uta C Hoppe
- Department of Internal Medicine II, Paracelsus Medical University, Muellner Hauptstr. 48, A-5020, Salzburg, Austria
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Chen GG, Yan JB, Wang XM, Zheng MZ, Jiang JP, Zhou XM, Cai B, Shen YL. Mechanism of uncoupling protein 2‑mediated myocardial injury in hypothermic preserved rat hearts. Mol Med Rep 2016; 14:1857-64. [PMID: 27356851 DOI: 10.3892/mmr.2016.5436] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 06/10/2016] [Indexed: 11/05/2022] Open
Abstract
In the present study, the alterations in uncoupling protein 2 (UCP2) expression following hypothermic preservation in rat hearts were investigated. Isolated rat hearts were preserved in Celsior solution for 3‑12 h followed by 60 min of reperfusion. The cardiac function was evaluated using the Langendorff perfusion system. UCP2 and silent mating type information regulation 2 homolog 1 (SIRT1) proteins were detected by western blot analysis. The ATP production and mitochondrial reactive oxygen species (ROS) levels were assessed. Subsequent to preservation in ice‑cold Celsior solution for 3‑12 h, the UCP2 protein expression in rat hearts was observed to increase in a time‑dependent manner. The UCP2 inhibitor genipin inhibited the hypothermic preservation‑induced cardiac dysfunction, prevented a decline in ATP production induced by 9 h of preservation, however had no effect on the hypothermic preservation‑induced increase in mitochondrial ROS levels. Compared with the control group, the SIRT1 protein expression in rat hearts reduced following hypothermic preservation. Compared with the 9‑h preservation group, Celsior solution supplemented with the SIRT1 activator resveratrol (20 or 40 µmol/l) inhibited UCP2 protein overexpression, prevented the decline in ATP production and resulted in an improvement cardiac function. The SIRT1 inhibitor EX‑527 abolished the resveratrol‑induced inhibition of UCP2 overexpression and cardiac protection in the hypothermic preserved rat heart. These observations suggest that downregulation of UCP2 expression in the hypothermic preserved rat heart in part initiated the protective mechanism via the SIRT1 pathway.
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Affiliation(s)
- Gai-Ge Chen
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Jin-Bin Yan
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Xu-Ming Wang
- Department of Pharmacology, Medicine School, Taizhou University, Taizhou, Zhejiang 317000, P.R. China
| | - Ming-Zhi Zheng
- Department of Pharmacology, Zhejiang Medical College, Hangzhou, Zhejiang 310053, P.R. China
| | - Jian-Ping Jiang
- Department of Clinical Medicine, Zhejiang Medical College, Hangzhou, Zhejiang 310053, P.R. China
| | - Xin-Mei Zhou
- Department of Physiology, Jiaxing University College of Medicine, Jiaxing, Zhejiang 314001, P.R. China
| | - Bin Cai
- Department of Medical Affairs, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, P.R. China
| | - Yue-Liang Shen
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
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Effects of central irisin administration on the uncoupling proteins in rat brain. Neurosci Lett 2016; 618:6-13. [DOI: 10.1016/j.neulet.2016.02.046] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Revised: 01/17/2016] [Accepted: 02/25/2016] [Indexed: 01/28/2023]
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Akhmedov AT, Rybin V, Marín-García J. Mitochondrial oxidative metabolism and uncoupling proteins in the failing heart. Heart Fail Rev 2015; 20:227-49. [PMID: 25192828 DOI: 10.1007/s10741-014-9457-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Despite significant progress in cardiovascular medicine, myocardial ischemia and infarction, progressing eventually to the final end point heart failure (HF), remain the leading cause of morbidity and mortality in the USA. HF is a complex syndrome that results from any structural or functional impairment in ventricular filling or blood ejection. Ultimately, the heart's inability to supply the body's tissues with enough blood may lead to death. Mechanistically, the hallmarks of the failing heart include abnormal energy metabolism, increased production of reactive oxygen species (ROS) and defects in excitation-contraction coupling. HF is a highly dynamic pathological process, and observed alterations in cardiac metabolism and function depend on the disease progression. In the early stages, cardiac remodeling characterized by normal or slightly increased fatty acid (FA) oxidation plays a compensatory, cardioprotective role. However, upon progression of HF, FA oxidation and mitochondrial oxidative activity are decreased, resulting in a significant drop in cardiac ATP levels. In HF, as a compensatory response to decreased oxidative metabolism, glucose uptake and glycolysis are upregulated, but this upregulation is not sufficient to compensate for a drop in ATP production. Elevated mitochondrial ROS generation and ROS-mediated damage, when they overwhelm the cellular antioxidant defense system, induce heart injury and contribute to the progression of HF. Mitochondrial uncoupling proteins (UCPs), which promote proton leak across the inner mitochondrial membrane, have emerged as essential regulators of mitochondrial membrane potential, respiratory activity and ROS generation. Although the physiological role of UCP2 and UCP3, expressed in the heart, has not been clearly established, increasing evidence suggests that these proteins by promoting mild uncoupling could reduce mitochondrial ROS generation and cardiomyocyte apoptosis and ameliorate thereby myocardial function. Further investigation on the alterations in cardiac UCP activity and regulation will advance our understanding of their physiological roles in the healthy and diseased heart and also may facilitate the development of novel and more efficient therapies.
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Affiliation(s)
- Alexander T Akhmedov
- The Molecular Cardiology and Neuromuscular Institute, 75 Raritan Avenue, Highland Park, NJ, 08904, USA
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Protective Effect of Peroxisome Proliferator-Activated Receptor α Activation against Cardiac Ischemia-Reperfusion Injury Is Related to Upregulation of Uncoupling Protein-3. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:3539649. [PMID: 26770648 PMCID: PMC4685116 DOI: 10.1155/2016/3539649] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 08/17/2015] [Accepted: 08/25/2015] [Indexed: 11/17/2022]
Abstract
Activation of peroxisome proliferator-activated receptor α (PPARα) confers cardioprotection, while its mechanism remains elusive. We investigated the protective effect of PPARα activation against cardiac ischemia-reperfusion injury in terms of the expression of uncoupling protein (UCP). Myocardial infarct size and UCP expression were measured in rats treated with WY-14643 20 mg/kg, a PPARα ligand, or vehicle. WY-14643 increased UCP3 expression in vivo. Myocardial infarct size was decreased in the WY-14643 group (76 ± 8% versus 42 ± 12%, P<0.05). During reperfusion, the incidence of arrhythmia was higher in the control group compared with the WY-14643 group (9/10 versus 3/10, P<0.05). H9c2 cells were incubated for 24 h with WY-14643 or vehicle. WY-14643 increased UCP3 expression in H9c2 cells. WY-14643 decreased hypoxia-stimulated ROS production. Cells treated with WY-14643 were more resistant to hypoxia-reoxygenation than the untreated cells. Knocking-down UCP3 by siRNA prevented WY-14643 from attenuating the production of ROS. UCP3 siRNA abolished the effect of WY-14643 on cell viability against hypoxia-reoxygenation. In summary, administration of PPARα agonist WY-14643 mitigated the extent of myocardial infarction and incidence of reperfusion-induced arrhythmia. PPARα activation conferred cytoprotective effect against hypoxia-reoxygenation. Associated mechanisms involved increased UCP3 expression and resultant attenuation of ROS production.
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31
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Thompson JW, Narayanan SV, Koronowski KB, Morris-Blanco K, Dave KR, Perez-Pinzon MA. Signaling pathways leading to ischemic mitochondrial neuroprotection. J Bioenerg Biomembr 2015; 47:101-10. [PMID: 25262285 PMCID: PMC4861652 DOI: 10.1007/s10863-014-9574-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 08/20/2014] [Indexed: 12/11/2022]
Abstract
There is extensive evidence that ischemic/reperfusion mediated mitochondrial dysfunction is a major contributor to ischemic damage. However data also indicates that mild ischemic stress induces mitochondrial dependent activation of ischemic preconditioning. Ischemic preconditioning is a neuroprotective mechanism which is activated upon a brief sub-injurious ischemic exposure and is sufficient to provide protection against a subsequent lethal ischemic insult. Current research demonstrates that mitochondria are not only the inducers of but are also an important target of ischemic preconditioning mediated protection. Numerous proteins and signaling pathways are activated by ischemic preconditioning which protect the mitochondria against ischemic damage. In this review we examine some of the proteins activated by ischemic precondition which counteracts the deleterious effects of ischemia/reperfusion thereby maintaining normal mitochondrial activity and lead to ischemic tolerance.
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Affiliation(s)
- John W Thompson
- Cerebral Vascular Disease Research Laboratories, Department of Neurology and Neuroscience Program, Miller School of Medicine, University of Miami, P.O. Box 016960, Miami, FL, 33136, USA
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32
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Graw JA, von Haefen C, Poyraz D, Möbius N, Sifringer M, Spies CD. Chronic Alcohol Consumption Leads to a Tissue Specific Expression of Uncoupling Protein-2. Int J Med Sci 2015; 12:995-9. [PMID: 26664262 PMCID: PMC4661299 DOI: 10.7150/ijms.13193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/11/2015] [Indexed: 01/06/2023] Open
Abstract
Uncoupling proteins (UCPs) are anion channels that can decouple the mitochondrial respiratory chain. "Mild uncoupling" of internal respiration reduces free radical production and oxidative cell stress. Chronic alcohol consumption is a potent inducer of oxidative stress in multiple tissues and regulates UCP-2 and -4 expression in the brain. To analyse the impact of chronic alcohol intake on UCP-2 expression in tissues with high endogenous UCP-2 contents, male Wistar rats (n=34) were treated with a 12-week 5% alcohol diet. In the lungs and the spleen of rats with a chronic alcohol diet cytochrome c release from mitochondria was significantly increased. Both organs did not show any altered gene and protein expression of UCP-2. Different to cerebral tissue chronic alcohol consumption has no regulatory effect on UCP-2 gene and protein expression in organs with a high endogenous UCP-2 content. Therefore, chronic alcohol consumption leads to a tissue specific expression of UCP-2.
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Affiliation(s)
- Jan A Graw
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany
| | - Clarissa von Haefen
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany
| | - Deniz Poyraz
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany
| | - Nadine Möbius
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany
| | - Marco Sifringer
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany
| | - Claudia D Spies
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany
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Abstract
The ability of an organism to convert organic molecules from the environment into energy is essential for the development of cellular structures, cell differentiation and growth. Mitochondria have a fundamental role in regulating metabolic pathways, and tight control of mitochondrial functions and dynamics is critical to maintaining adequate energy balance. In complex organisms, such as mammals, it is also essential that the metabolic demands of various tissues are coordinated to ensure that the energy needs of the whole body are effectively met. Within the arcuate nucleus of the hypothalamus, the NPY-AgRP and POMC neurons have a crucial role in orchestrating the regulation of hunger and satiety. Emerging findings from animal studies have revealed an important function for mitochondrial dynamics within these two neuronal populations, which facilitates the correct adaptive responses of the whole body to changes in the metabolic milieu. The main proteins implicated in these studies are the mitofusins, Mfn1 and Mfn2, which are regulators of mitochondrial dynamics. In this Review, we provide an overview of the mechanisms by which mitochondria are involved in the central regulation of energy balance and discuss the implications of mitochondrial dysfunction for metabolic disorders.
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Affiliation(s)
- Carole M Nasrallah
- Program in Integrative Cell Signalling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, SHM L-200, PO Box 208074, New Haven, CT 06520-8074, USA
| | - Tamas L Horvath
- Program in Integrative Cell Signalling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, SHM L-200, PO Box 208074, New Haven, CT 06520-8074, USA
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Perreten Lambert H, Zenger M, Azarias G, Chatton JY, Magistretti PJ, Lengacher S. Control of mitochondrial pH by uncoupling protein 4 in astrocytes promotes neuronal survival. J Biol Chem 2014; 289:31014-28. [PMID: 25237189 DOI: 10.1074/jbc.m114.570879] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Brain activity is energetically costly and requires a steady and highly regulated flow of energy equivalents between neural cells. It is believed that a substantial share of cerebral glucose, the major source of energy of the brain, will preferentially be metabolized in astrocytes via aerobic glycolysis. The aim of this study was to evaluate whether uncoupling proteins (UCPs), located in the inner membrane of mitochondria, play a role in setting up the metabolic response pattern of astrocytes. UCPs are believed to mediate the transmembrane transfer of protons, resulting in the uncoupling of oxidative phosphorylation from ATP production. UCPs are therefore potentially important regulators of energy fluxes. The main UCP isoforms expressed in the brain are UCP2, UCP4, and UCP5. We examined in particular the role of UCP4 in neuron-astrocyte metabolic coupling and measured a range of functional metabolic parameters including mitochondrial electrical potential and pH, reactive oxygen species production, NAD/NADH ratio, ATP/ADP ratio, CO2 and lactate production, and oxygen consumption rate. In brief, we found that UCP4 regulates the intramitochondrial pH of astrocytes, which acidifies as a consequence of glutamate uptake, with the main consequence of reducing efficiency of mitochondrial ATP production. The diminished ATP production is effectively compensated by enhancement of glycolysis. This nonoxidative production of energy is not associated with deleterious H2O2 production. We show that astrocytes expressing more UCP4 produced more lactate, which is used as an energy source by neurons, and had the ability to enhance neuronal survival.
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Affiliation(s)
- Hélène Perreten Lambert
- From the School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Manuel Zenger
- From the School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Guillaume Azarias
- the Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland, and
| | - Jean-Yves Chatton
- the Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland, and
| | - Pierre J Magistretti
- From the School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland, the King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia, the Center for Psychiatric Neuroscience, 1008 Prilly-Lausanne, Switzerland
| | - Sylvain Lengacher
- From the School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland, the Center for Psychiatric Neuroscience, 1008 Prilly-Lausanne, Switzerland
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Bermejo-Nogales A, Calduch-Giner JA, Pérez-Sánchez J. Tissue-specific gene expression and functional regulation of uncoupling protein 2 (UCP2) by hypoxia and nutrient availability in gilthead sea bream (Sparus aurata): implications on the physiological significance of UCP1-3 variants. FISH PHYSIOLOGY AND BIOCHEMISTRY 2014; 40:751-762. [PMID: 24154671 DOI: 10.1007/s10695-013-9882-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 10/12/2013] [Indexed: 06/02/2023]
Abstract
The aim of this study was to assess in an integrative manner the physiological regulation of uncoupling protein 2 (UCP2) in gilthead sea bream. A contig of 1,325 nucleotides in length with an open reading frame of 307 amino acids was recognized as UCP2 after searches in our transcriptome reference database ( http://www.nutrigroup-iats.org/seabreamdb ). Gene expression mapping by quantitative real-time PCR revealed a ubiquitous profile that clearly differs from that of UCP1 and UCP3 variants with the greatest abundance in liver and white skeletal muscle, respectively. The greatest abundance of UCP2 transcripts was found in the heart, with a relatively high expression level in blood cells, where UCP1 and UCP3 transcripts were practically undetectable. Functional studies revealed that UCP2 mRNA expression remains either unaltered or up-regulated upon feed restriction in glycolytic (white skeletal muscle) and highly oxidative muscle tissues (heart and red skeletal muscle), respectively. In contrast, exposure to hypoxic conditions (18-19% oxygen saturation) markedly down-regulated the UCP2 mRNA expression in blood cells in a cellular environment with increased haematocrit, blood haemoglobin content, and circulating levels of glucose and lactate, and total plasma antioxidant activity. These findings demonstrated that UCP2 expression is highly regulated at the transcriptional level, arising this UCP variant as an important piece of the complex trade-off between metabolic and redox sensors. This feature would avoid the activation of futile cycles of energy wastage if changes in tissue oxidative and antioxidant metabolic capabilities are able to maintain the production of reactive oxygen species at a low regulated level.
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Affiliation(s)
- Azucena Bermejo-Nogales
- Nutrigenomics and Fish Growth Endocrinology Group, Department of Biology, Culture and Pathology of Marine Species, Institute of Aquaculture Torre de la Sal, CSIC, 12595, Ribera de Cabanes, Castellón, Spain
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Ozcan C, Palmeri M, Horvath TL, Russell KS, Russell RR. Role of uncoupling protein 3 in ischemia-reperfusion injury, arrhythmias, and preconditioning. Am J Physiol Heart Circ Physiol 2013; 304:H1192-200. [PMID: 23457013 DOI: 10.1152/ajpheart.00592.2012] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Overexpression of mitochondrial uncoupling proteins (UCPs) attenuates ischemia-reperfusion (I/R) injury in cultured cardiomyocytes. However, it is not known whether UCPs play an essential role in cardioprotection in the intact heart. This study evaluated the cardioprotective efficacy of UCPs against I/R injury and characterized the mechanism of UCP-mediated protection in addition to the role of UCPs in ischemic preconditioning (IPC). Cardiac UCP3 knockout (UCP3(-/-)) and wild-type (WT) mice hearts were subjected to ex vivo and in vivo models of I/R injury and IPC. Isolated UCP3(-/-) mouse hearts were retrogradely perfused and found to have poorer recovery of left ventricular function compared with WT hearts under I/R conditions. In vivo occlusion of the left coronary artery resulted in twofold larger infarcts in UCP3(-/-) mice compared with WT mice. Moreover, the incidence of in vivo I/R arrhythmias was higher in UCP3(-/-) mice. Myocardial energetics were significantly impaired with I/R, as reflected by a decreased ATP content and an increase in the AMP-to-ATP ratio. UCP3(-/-) hearts generated more reactive oxygen species (ROS) than WT hearts during I/R. Pretreatment of UCP3(-/-) hearts with the pharmacological uncoupling agent carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone improved postischemic functional recovery. Also the protective efficacy of IPC was abolished in UCP3(-/-) mice. We conclude that UCP3 plays a critical role in cardioprotection against I/R injury and the IPC phenomenon. There is increased myocardial vulnerability to I/R injury in hearts lacking UCP3. The mechanisms of UCP3-mediated cardioprotection include regulation of myocardial energetics and ROS generation by UCP3 during I/R.
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Affiliation(s)
- Cevher Ozcan
- Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
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37
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Jabůrek M, Ježek J, Zelenka J, Ježek P. Antioxidant activity by a synergy of redox-sensitive mitochondrial phospholipase A2 and uncoupling protein-2 in lung and spleen. Int J Biochem Cell Biol 2013; 45:816-25. [PMID: 23354121 DOI: 10.1016/j.biocel.2013.01.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 01/11/2013] [Accepted: 01/14/2013] [Indexed: 12/24/2022]
Abstract
Mitochondrial uncoupling protein-2 (UCP2) has been suggested to participate in the attenuation of the reactive oxygen species production, but the mechanism of action and the physiological significance of UCP2 activity remain controversial. Here we tested the hypothesis that UCP2 provides feedback downregulation of oxidative stress in vivo via synergy with an H2O2-activated mitochondrial calcium-independent phospholipase A2 (mt-iPLA2). Tert-butylhydroperoxide or H2O2 induced free fatty acid release from mitochondrial membranes as detected by gas chromatography/mass spectrometry, which was inhibited by r-bromoenol lactone (r-BEL) but not by its stereoisomer s-BEL, suggesting participation of mt-iPLA2γ isoform. Tert-butylhydroperoxide or H2O2 also induced increase in respiration and decrease in mitochondrial membrane potential in lung and spleen mitochondria from control but not UCP2-knockout mice. These data suggest that mt-iPLA2γ-dependent release of free fatty acids promotes UCP2-dependent uncoupling. Upon such uncoupling, mitochondrial superoxide formation decreased instantly also in the s-BEL presence, but not when mt-iPLA2 was blocked by R-BEL and not in mitochondria from UCP2-knockout mice. Mt-iPLA2γ was alternatively activated by H2O2 produced probably in conjunction with the electron-transferring flavoprotein:ubiquinone oxidoreductase (ETFQOR), acting in fatty acid β-oxidation. Palmitoyl-d,l-carnitine addition to mouse lung mitochondria, respiring with succinate plus rotenone, caused a respiration increase that was sensitive to r-BEL and insensitive to s-BEL. We thus demonstrate for the first time that UCP2, functional due to fatty acids released by redox-activated mt-iPLA2γ, suppresses mitochondrial superoxide production by its uncoupling action. In conclusion, H2O2-activated mt-iPLA2γ and UCP2 act in concert to protect against oxidative stress.
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Affiliation(s)
- Martin Jabůrek
- Department of Membrane Transport Biophysics, No. 75, Institute of Physiology, Academy of Sciences, Vídeňská 1083, Prague 14220, Czech Republic
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Rupprecht A, Bräuer AU, Smorodchenko A, Goyn J, Hilse KE, Shabalina IG, Infante-Duarte C, Pohl EE. Quantification of uncoupling protein 2 reveals its main expression in immune cells and selective up-regulation during T-cell proliferation. PLoS One 2012; 7:e41406. [PMID: 22870219 PMCID: PMC3411681 DOI: 10.1371/journal.pone.0041406] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 06/25/2012] [Indexed: 12/11/2022] Open
Abstract
Uncoupling protein 2 (UCP2) is an inner mitochondrial membrane protein. Although the protein was discovered in 1997, its function and even its tissue distribution are still under debate. Here we present a quantitative analysis of mRNA and protein expression in various mice tissues, revealing that UCP2 is mainly expressed in organs and cells associated with the immune system. Although the UCP2 gene is present in the brain, as demonstrated using quantitative RT-PCR, the protein was not detectable in neurons under physiological conditions. Instead, we could detect UCP2 in microglia, which act in the immune defense of the central nervous system. In lymphocytes, activation led to a ten-fold increase of UCP2 protein expression simultaneously to the increase in levels of other mitochondrial proteins, whereas lymphocyte re-stimulation resulted in the selective increase of UCP2. The highest detected level of UCP2 expression in stimulated T-cells (0.54 ng/(µg total cellular protein)) was approximately 200 times lower than the level of UCP1 in brown adipose tissue from room temperature acclimated mice. Both the UCP2 expression pattern and the time course of up-regulation in stimulated T-cells imply UCP2’s involvement in the immune response, probably by controlling the metabolism during cell proliferation.
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Affiliation(s)
- Anne Rupprecht
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Anja U. Bräuer
- Institute of Cell Biology and Neurobiology, Charité – Universitätsmedizin, Berlin, Germany
| | - Alina Smorodchenko
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Justus Goyn
- Institute of Cell Biology and Neurobiology, Charité – Universitätsmedizin, Berlin, Germany
| | - Karolina E. Hilse
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | | | - Carmen Infante-Duarte
- Experimental and Clinical Research Center, a joint cooperation between the Charité - Universitätsmedizin Berlin and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Elena E. Pohl
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
- * E-mail:
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Molecular identification and functional characterisation of uncoupling protein 4 in larva and pupa fat body mitochondria from the beetle Zophobas atratus. Comp Biochem Physiol B Biochem Mol Biol 2012; 162:126-33. [DOI: 10.1016/j.cbpb.2012.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 03/26/2012] [Accepted: 03/27/2012] [Indexed: 01/20/2023]
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Ramsden DB, Ho PW, Ho JW, Liu H, So DH, Tse H, Chan K, Ho S. Human neuronal uncoupling proteins 4 and 5 (UCP4 and UCP5): structural properties, regulation, and physiological role in protection against oxidative stress and mitochondrial dysfunction. Brain Behav 2012; 2:468-78. [PMID: 22950050 PMCID: PMC3432969 DOI: 10.1002/brb3.55] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 03/07/2012] [Accepted: 03/09/2012] [Indexed: 01/07/2023] Open
Abstract
Uncoupling proteins (UCPs) belong to a large family of mitochondrial solute carriers 25 (SLC25s) localized at the inner mitochondrial membrane. UCPs transport protons directly from the intermembrane space to the matrix. Of five structural homologues (UCP1 to 5), UCP4 and 5 are principally expressed in the central nervous system (CNS). Neurons derived their energy in the form of ATP that is generated through oxidative phosphorylation carried out by five multiprotein complexes (Complexes I-V) embedded in the inner mitochondrial membrane. In oxidative phosphorylation, the flow of electrons generated by the oxidation of substrates through the electron transport chain to molecular oxygen at Complex IV leads to the transport of protons from the matrix to the intermembrane space by Complex I, III, and IV. This movement of protons to the intermembrane space generates a proton gradient (mitochondrial membrane potential; MMP) across the inner membrane. Complex V (ATP synthase) uses this MMP to drive the conversion of ADP to ATP. Some electrons escape to oxygen-forming harmful reactive oxygen species (ROS). Proton leakage back to the matrix which bypasses Complex V resulting in a major reduction in ROS formation while having a minimal effect on MMP and hence, ATP synthesis; a process termed "mild uncoupling." UCPs act to promote this proton leakage as means to prevent excessive build up of MMP and ROS formation. In this review, we discuss the structure and function of mitochondrial UCPs 4 and 5 and factors influencing their expression. Hypotheses concerning the evolution of the two proteins are examined. The protective mechanisms of the two proteins against neurotoxins and their possible role in regulating intracellular calcium movement, particularly with regard to the pathogenesis of Parkinson's disease are discussed.
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Affiliation(s)
- David B. Ramsden
- School of Medicine and School of Biosciences, University of Birmingham, United Kingdom
| | - Philip W.‐L. Ho
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong, PR China
- Research Centre of Heart, Brain, Hormone and Healthy Aging (HBHA), University of Hong Kong, Hong Kong, PR China
| | - Jessica W.‐M. Ho
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong, PR China
| | - Hui‐Fang Liu
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong, PR China
| | - Danny H.‐F. So
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong, PR China
| | - Ho‐Man Tse
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong, PR China
| | - Koon‐Ho Chan
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong, PR China
- Research Centre of Heart, Brain, Hormone and Healthy Aging (HBHA), University of Hong Kong, Hong Kong, PR China
| | - Shu‐Leong Ho
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong, PR China
- Research Centre of Heart, Brain, Hormone and Healthy Aging (HBHA), University of Hong Kong, Hong Kong, PR China
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Persson MF, Franzén S, Catrina SB, Dallner G, Hansell P, Brismar K, Palm F. Coenzyme Q10 prevents GDP-sensitive mitochondrial uncoupling, glomerular hyperfiltration and proteinuria in kidneys from db/db mice as a model of type 2 diabetes. Diabetologia 2012; 55:1535-43. [PMID: 22311417 DOI: 10.1007/s00125-012-2469-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 12/29/2011] [Indexed: 01/16/2023]
Abstract
AIMS/HYPOTHESIS Increased oxygen consumption results in kidney tissue hypoxia, which is proposed to contribute to the development of diabetic nephropathy. Oxidative stress causes increased oxygen consumption in type 1 diabetic kidneys, partly mediated by uncoupling protein-2 (UCP-2)-induced mitochondrial uncoupling. The present study investigates the role of UCP-2 and oxidative stress in mitochondrial oxygen consumption and kidney function in db/db mice as a model of type 2 diabetes. METHODS Mitochondrial oxygen consumption, glomerular filtration rate and proteinuria were investigated in db/db mice and corresponding controls with and without coenzyme Q10 (CoQ10) treatment. RESULTS Untreated db/db mice displayed mitochondrial uncoupling, manifested as glutamate-stimulated oxygen consumption (2.7 ± 0.1 vs 0.2 ± 0.1 pmol O(2) s(-1) [mg protein](-1)), glomerular hyperfiltration (502 ± 26 vs 385 ± 3 μl/min), increased proteinuria (21 ± 2 vs 14 ± 1, μg/24 h), mitochondrial fragmentation (fragmentation score 2.4 ± 0.3 vs 0.7 ± 0.1) and size (1.6 ± 0.1 vs 1 ± 0.0 μm) compared with untreated controls. All alterations were prevented or reduced by CoQ10 treatment. Mitochondrial uncoupling was partly inhibited by the UCP inhibitor GDP (-1.1 ± 0.1 pmol O(2) s(-1) [mg protein](-1)). UCP-2 protein levels were similar in untreated control and db/db mice (67 ± 9 vs 67 ± 4 optical density; OD) but were reduced in CoQ10 treated groups (43 ± 2 and 38 ± 7 OD). CONCLUSIONS/INTERPRETATION db/db mice displayed oxidative stress-mediated activation of UCP-2, which resulted in mitochondrial uncoupling and increased oxygen consumption. CoQ10 prevented altered mitochondrial function and morphology, glomerular hyperfiltration and proteinuria in db/db mice, highlighting the role of mitochondria in the pathogenesis of diabetic nephropathy and the benefits of preventing increased oxidative stress.
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Affiliation(s)
- M Friederich Persson
- Department of Medical Cell Biology, Biomedical Center, Husargatan 3, Box 571, 751 23 Uppsala, Sweden.
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Ho PW, Ho JW, Liu HF, So DH, Tse ZH, Chan KH, Ramsden DB, Ho SL. Mitochondrial neuronal uncoupling proteins: a target for potential disease-modification in Parkinson's disease. Transl Neurodegener 2012; 1:3. [PMID: 23210978 PMCID: PMC3506996 DOI: 10.1186/2047-9158-1-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 01/13/2012] [Indexed: 12/21/2022] Open
Abstract
This review gives a brief insight into the role of mitochondrial dysfunction and oxidative stress in the converging pathogenic processes involved in Parkinson's disease (PD). Mitochondria provide cellular energy in the form of ATP via oxidative phosphorylation, but as an integral part of this process, superoxides and other reactive oxygen species are also produced. Excessive free radical production contributes to oxidative stress. Cells have evolved to handle such stress via various endogenous anti-oxidant proteins. One such family of proteins is the mitochondrial uncoupling proteins (UCPs), which are anion carriers located in the mitochondrial inner membrane. There are five known homologues (UCP1 to 5), of which UCP4 and 5 are predominantly expressed in neural cells. In a series of previous publications, we have shown how these neuronal UCPs respond to 1-methyl-4-phenylpyridinium (MPP+; toxic metabolite of MPTP) and dopamine-induced toxicity to alleviate neuronal cell death by preserving ATP levels and mitochondrial membrane potential, and reducing oxidative stress. We also showed how their expression can be influenced by nuclear factor kappa-B (NF-κB) signaling pathway specifically in UCP4. Furthermore, we previously reported an interesting link between PD and metabolic processes through the protective effects of leptin (hormone produced by adipocytes) acting via UCP2 against MPP+-induced toxicity. There is increasing evidence that these endogenous neuronal UCPs can play a vital role to protect neurons against various pathogenic stresses including those associated with PD. Their expression, which can be induced, may well be a potential therapeutic target for various drugs to alleviate the harmful effects of pathogenic processes in PD and hence modify the progression of this disease.
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Affiliation(s)
- Philip Wl Ho
- Division of Neurology, Department of Medicine, University of Hong Kong, Pokfulam, Hong Kong SAR, China.
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Ji C, Guo W, Zhang M, Lu X, Ni Y, Guo X. Caenorhabditis elegans ucp-4 regulates fat metabolism: Suppression of ucp-4 expression induced obese phenotype and caused impairment of insulin like pathway. Gene 2012; 491:158-64. [DOI: 10.1016/j.gene.2011.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 09/30/2011] [Accepted: 10/01/2011] [Indexed: 10/16/2022]
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Mitochondrial uncoupling protein 2 (UCP2) in glucose and lipid metabolism. Trends Mol Med 2011; 18:52-8. [PMID: 21917523 DOI: 10.1016/j.molmed.2011.08.003] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 08/09/2011] [Accepted: 08/18/2011] [Indexed: 12/18/2022]
Abstract
Nutrient availability is critical for the physiological functions of all tissues. By contrast, an excess of nutrients such as carbohydrate and fats impair health and shorten life due by stimulating chronic diseases, including diabetes, cancer and neurodegeneration. The control of circulating glucose and lipid levels involve mitochondria in both central and peripheral mechanisms of metabolism regulation. Mitochondrial uncoupling protein 2 (UCP2) has been implicated in physiological and pathological processes related to glucose and lipid metabolism, and in this review we discuss the latest data on the relationships between UCP2 and glucose and lipid sensing from the perspective of specific hypothalamic neuronal circuits and peripheral tissue functions. The goal is to provide a framework for discussion of future therapeutic strategies for metabolism-related chronic diseases.
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Gao CL, Ni YH, Liu G, Chen XH, Ji CB, Qin DN, Kou CZ, Zhu C, Zhang CM, Xia ZK, Guo XR. UCP4 overexpression improves fatty acid oxidation and insulin sensitivity in L6 myocytes. J Bioenerg Biomembr 2011; 43:109-18. [PMID: 21607879 DOI: 10.1007/s10863-011-9344-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2010] [Accepted: 11/12/2010] [Indexed: 12/12/2022]
Abstract
Obesity, which is caused by energy uptake being greater than energy expenditure, is widely prevalent today. Currently, only a limited number of efficient interventional strategies are available for the prevention of obesity. Previous studies have shown that UCP4 transcription occurs at a considerable level in mouse skeletal muscle; however, the exact functions of UCP4 remain unclear. In this study, we investigated the effect of UCP4 on mitochondrial function and insulin sensitivity in mature L6 myocytes. UCP4 overexpression in L6 myocytes induced increased mitochondrial carnitine palmitoyltransferase 1A (CPT1A) and decreased citrate synthase (CS) mRNA in the basal condition (i.e., in the absence of insulin). UCP4 overexpression significantly improved insulin sensitivity, increased tyrosine phosphorylation of IRS-1 in the presence of insulin, and significantly reduced intracellular triglyceride (TG). Additionally, intracellular ATP content and mitochondrial membrane potential were downregulated. We also observed that intracellular ROS, mitochondrial morphology, and mitochondrial mtDNA copy number were maintained upon UCP4 expression, with no change in mitochondrial fusion and fission. In summary, our findings provide evidence to show that UCP4 overexpression reduced the insulin sensitivity and mitochondrial fatty acid oxidation of L6 myocytes. These findings support the notion that UCPs are ideal targets for treatment of insulin resistance.
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Affiliation(s)
- Chun-Lin Gao
- Department of Pediatrics, Jinling Hospital, Nanjing, China
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Dorsa KK, Santos MVD, Silva MRDD. Enhancing T3 and cAMP responsive gene participation in the thermogenic regulation of fuel oxidation pathways. ACTA ACUST UNITED AC 2011; 54:381-9. [PMID: 20625650 DOI: 10.1590/s0004-27302010000400007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 02/09/2010] [Indexed: 11/22/2022]
Abstract
OBJECTIVE We sought to identify glycolysis, glycogenolysis, lipolysis, Krebs cycle, respiratory chain, and oxidative phosphorylation enzymes simultaneously regulated by T3 and cAMP. MATERIALS AND METHODS We performed in silico analysis of 56 promoters to search for cis-cAMP (CREB) and cis-thyroid (TRE) response elements, considering UCP1, SERCA2 and glyceraldehyde 3-phosphate dehydrogenase as reference. Only regulatory regions with prior in vitro validation were selected. RESULTS 29/56 enzymes presented potential TREs in their regulatory sequence, and some scored over 0.80 (better predictive value 1): citrate synthase, phosphoglucose isomerase, succinate dehydrogenases A/C, UCP3, UCP2, UCP4, UCP5, phosphoglycerate mutase, glyceraldehyde 3-P dehydrogenase, glucokinase, malate dehydrogenase, acyl-CoA transferase (thiolase), cytochrome a3, and lactate dehydrogenase. Moreover, some enzymes have not yet been described in the literature as genomically regulated by T3. CONCLUSION Our results point to other enzymes which may possibly be regulated by T3 and CREB, and speculate their joint roles in contributing to the optimal thermogenic acclimation.
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Wojtczak L, Lebiedzińska M, Suski JM, Więckowski MR, Schönfeld P. Inhibition by purine nucleotides of the release of reactive oxygen species from muscle mitochondria: indication for a function of uncoupling proteins as superoxide anion transporters. Biochem Biophys Res Commun 2011; 407:772-6. [PMID: 21439941 DOI: 10.1016/j.bbrc.2011.03.098] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 03/18/2011] [Indexed: 02/07/2023]
Abstract
Release of reactive oxygen species (ROS), measured as the sum of hydrogen peroxide (H₂O₂) and superoxide anion radical (O₂·⁻), from respiring rat heart and skeletal muscle mitochondria was significantly decreased by millimolar concentrations of GTP or GDP. Attempts to differentiate between the two forms of ROS showed that the release of O₂·⁻ rather than that of H₂O₂ was affected. Meanwhile, intramitochondrial ROS accumulation, measured by inactivation of aconitase, increased. These results suggest that guanine nucleotides inhibit the release of O₂·⁻ from mitochondria. As these nucleotides are known inhibitors of uncoupling proteins (UCPs), it is proposed that UCPs may function as carriers of O₂·⁻, thus enabling its removal from the matrix compartment.
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Affiliation(s)
- Lech Wojtczak
- Nencki Institute of Experimental Biology, Warsaw, Poland.
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Zong H, Wang CC, Vaitheesvaran B, Kurland IJ, Hong W, Pessin JE. Enhanced energy expenditure, glucose utilization, and insulin sensitivity in VAMP8 null mice. Diabetes 2011; 60:30-8. [PMID: 20876717 PMCID: PMC3012186 DOI: 10.2337/db10-0231] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Previous studies have demonstrated that the VAMP8 protein plays a complex role in the control of granule secretion, transport vesicle trafficking, phagocytosis, and endocytosis. The present study was aimed to investigate the role of VAMP8 in mediating GLUT4 trafficking and therefore insulin action in mice. RESEARCH DESIGN AND METHODS Physiological parameters were measured using Oxymax indirect calorimetry system in 12-week-old VAMP8 null mice. Dynamic analysis of glucose homeostasis was assessed using euglycemic-hyperinsulinemic clamp coupled with tracer radioactively labeled 2-deoxyglucose. Insulin stimulated GLUT4 protein expressions on muscle cell surface were examined by immunofluorescence microscopy. RESULTS VAMP8 null mice display reduced adiposity with increased energy expenditure despite normal food intake and reduced spontaneous locomotor activity. In parallel, the VAMP8 null mice also had fasting hypoglycemia (84 ± 11 vs. 115 ± 4) and enhanced glucose tolerance with increased insulin sensitivity due to increases in both basal and insulin-stimulated glucose uptake in skeletal muscle (0.19 ± 0.04 vs. 0.09 ± 0.01 mmol/kg/min during basal, 0.6 ± 0.04 vs. 0.31 ± 0.06 mmol/kg/min during clamp in red-gastrocnemius muscle, P < 0.05). Consistent with a role for VAMP8 in the endocytosis of the insulin-responsive GLUT4, sarcolemma GLUT4 protein levels were increased in both the basal and insulin-stimulated states without any significant change in the total amount of GLUT4 protein or related facilitative glucose transporters present in skeletal muscle, GLUT1, GLUT3, and GLUT11. CONCLUSIONS These data demonstrate that, in the absence of VAMP8, the relative subcellular distribution of GLUT4 is altered, resulting in increased sarcolemma levels that can account for increased glucose clearance and insulin sensitivity.
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Affiliation(s)
- Haihong Zong
- Department of Medicine and Molecular Pharmacology, The Albert Einstein College of Medicine, Bronx, New York
| | - Cheng-Chun Wang
- Membrane Biology Laboratory, Institute of Molecular and Cell Biology, Singapore
| | - Bhavapriya Vaitheesvaran
- Department of Medicine and Molecular Pharmacology, The Albert Einstein College of Medicine, Bronx, New York
| | - Irwin J. Kurland
- Department of Medicine and Molecular Pharmacology, The Albert Einstein College of Medicine, Bronx, New York
| | - Wanjin Hong
- Membrane Biology Laboratory, Institute of Molecular and Cell Biology, Singapore
| | - Jeffrey E. Pessin
- Department of Medicine and Molecular Pharmacology, The Albert Einstein College of Medicine, Bronx, New York
- Corresponding author: Jeffrey E. Pessin,
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Bergman C, Kashiwaya Y, Veech RL. The effect of pH and free Mg2+ on ATP linked enzymes and the calculation of Gibbs free energy of ATP hydrolysis. J Phys Chem B 2010; 114:16137-46. [PMID: 20866109 DOI: 10.1021/jp105723r] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The apparent equilibrium constants, K′, of biochemical reactions containing substrates which bind [Mg2+] unequally can be significantly altered by changes in free intracellular [Mg2+]. Intracellular free [Mg2+] can be estimated by measurements of [citrate]/[isocitrate], a ratio known to vary with tissue free [Mg2+]. The combined equilibrium constant for glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, and triose phosphate isomerase for the three reactions (K(GG-TPI)′) was corrected using new binding constants for dihydroxyacetone-phosphate and 3-phosphoglycerate. The result of this calculation is demonstrated in the calculation of the free energy of ATP hydrolysis. In addition, the dependence of the equilibrium constant for the glutamine synthetase reaction on pH and free [Mg2+] was demonstrated. Furthermore, a theory linking the ΔG′ value of mitochondrial complex I−II and the cytosolic ΔG′ value of ATP hydrolysis is discussed with evidence from previous publications.
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Affiliation(s)
- Christian Bergman
- Laboratory of Metabolic Control, NIAAA, NIH, DHHS, 5625 Fishers Lane, Bethesda, Maryland 20892, USA
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Kashiwaya Y, Pawlosky R, Markis W, King MT, Bergman C, Srivastava S, Murray A, Clarke K, Veech RL. A ketone ester diet increases brain malonyl-CoA and Uncoupling proteins 4 and 5 while decreasing food intake in the normal Wistar Rat. J Biol Chem 2010; 285:25950-6. [PMID: 20529850 PMCID: PMC2923987 DOI: 10.1074/jbc.m110.138198] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 05/25/2010] [Indexed: 01/20/2023] Open
Abstract
Three groups of male Wistar rats were pair fed NIH-31 diets for 14 days to which were added 30% of calories as corn starch, palm oil, or R-3-hydroxybutyrate-R-1,3-butanediol monoester (3HB-BD ester). On the 14th day, animal brains were removed by freeze-blowing, and brain metabolites measured. Animals fed the ketone ester diet had elevated mean blood ketone bodies of 3.5 mm and lowered plasma glucose, insulin, and leptin. Despite the decreased plasma leptin, feeding the ketone ester diet ad lib decreased voluntary food intake 2-fold for 6 days while brain malonyl-CoA was increased by about 25% in ketone-fed group but not in the palm oil fed group. Unlike the acute effects of ketone body metabolism in the perfused working heart, there was no increased reduction in brain free mitochondrial [NAD(+)]/[NADH] ratio nor in the free energy of ATP hydrolysis, which was compatible with the observed 1.5-fold increase in brain uncoupling proteins 4 and 5. Feeding ketone ester or palm oil supplemented diets decreased brain L-glutamate by 15-20% and GABA by about 34% supporting the view that fatty acids as well as ketone bodies can be metabolized by the brain.
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Affiliation(s)
- Yoshihiro Kashiwaya
- From the Laboratory of Metabolic Control, NIAAA, National Institutes of Health, Rockville, Maryland 20852-9047
| | - Robert Pawlosky
- From the Laboratory of Metabolic Control, NIAAA, National Institutes of Health, Rockville, Maryland 20852-9047
| | - William Markis
- From the Laboratory of Metabolic Control, NIAAA, National Institutes of Health, Rockville, Maryland 20852-9047
| | - M. Todd King
- From the Laboratory of Metabolic Control, NIAAA, National Institutes of Health, Rockville, Maryland 20852-9047
| | - Christian Bergman
- From the Laboratory of Metabolic Control, NIAAA, National Institutes of Health, Rockville, Maryland 20852-9047
| | - Shireesh Srivastava
- From the Laboratory of Metabolic Control, NIAAA, National Institutes of Health, Rockville, Maryland 20852-9047
| | - Andrew Murray
- the Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge CB2 3EG, United Kingdom, and
| | - Kieran Clarke
- the Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Richard L. Veech
- From the Laboratory of Metabolic Control, NIAAA, National Institutes of Health, Rockville, Maryland 20852-9047
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