1
|
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.
Collapse
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
| |
Collapse
|
2
|
Michel LYM. Extracellular Vesicles in Adipose Tissue Communication with the Healthy and Pathological Heart. Int J Mol Sci 2023; 24:ijms24097745. [PMID: 37175451 PMCID: PMC10177965 DOI: 10.3390/ijms24097745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/11/2023] [Accepted: 04/16/2023] [Indexed: 05/15/2023] Open
Abstract
Adipose tissue and its diverse cell types constitute one of the largest endocrine organs. With multiple depot locations, adipose tissue plays an important regulatory role through paracrine and endocrine communication, particularly through the secretion of a wide range of bioactive molecules, such as nucleic acids, proteins, lipids or adipocytokines. Over the past several years, research has uncovered a myriad of interorgan communication signals mediated by small lipid-derived nanovesicles known as extracellular vesicles (EVs), in which secreted bioactive molecules are stably transported as cargo molecules and delivered to adjacent cells or remote organs. EVs constitute an essential part of the human adipose secretome, and there is a growing body of evidence showing the crucial implications of adipose-derived EVs in the regulation of heart function and its adaptative capacity. The adipose tissue modifications and dysfunction observed in obesity and aging tremendously affect the adipose-EV secretome, with important consequences for the myocardium. The present review presents a comprehensive analysis of the findings in this novel area of research, reports the key roles played by adipose-derived EVs in interorgan cross-talk with the heart and discusses their implications in physiological and pathological conditions affecting adipose tissue and/or the heart (pressure overload, ischemia, diabetic cardiomyopathy, etc.).
Collapse
Affiliation(s)
- Lauriane Y M Michel
- Pole of Pharmacology and Therapeutics, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain (UCLouvain), 57 Avenue Hippocrate, 1200 Brussels, Belgium
| |
Collapse
|
3
|
Barnstable CJ, Zhang M, Tombran-Tink J. Uncoupling Proteins as Therapeutic Targets for Neurodegenerative Diseases. Int J Mol Sci 2022; 23:5672. [PMID: 35628482 PMCID: PMC9144266 DOI: 10.3390/ijms23105672] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/14/2022] [Accepted: 05/16/2022] [Indexed: 02/05/2023] Open
Abstract
Most of the major retinal degenerative diseases are associated with significant levels of oxidative stress. One of the major sources contributing to the overall level of stress is the reactive oxygen species (ROS) generated by mitochondria. The driving force for ROS production is the proton gradient across the inner mitochondrial membrane. This gradient can be modulated by members of the uncoupling protein family, particularly the widely expressed UCP2. The overexpression and knockout studies of UCP2 in mice have established the ability of this protein to provide neuroprotection in a number of animal models of neurological disease, including retinal diseases. The expression and activity of UCP2 are controlled at the transcriptional, translational and post-translational levels, making it an ideal candidate for therapeutic intervention. In addition to regulation by a number of growth factors, including the neuroprotective factors LIF and PEDF, small molecule activators of UCP2 have been found to reduce mitochondrial ROS production and protect against cell death both in culture and animal models of retinal degeneration. Such studies point to the development of new therapeutics to combat a range of blinding retinal degenerative diseases and possibly other diseases in which oxidative stress plays a key role.
Collapse
Affiliation(s)
- Colin J. Barnstable
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA;
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin 300384, China;
| | - Mingliang Zhang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin 300384, China;
| | - Joyce Tombran-Tink
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA;
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin 300384, China;
| |
Collapse
|
4
|
Stanzione R, Forte M, Cotugno M, Bianchi F, Marchitti S, Busceti CL, Fornai F, Rubattu S. Uncoupling Protein 2 as a Pathogenic Determinant and Therapeutic Target in Cardiovascular and Metabolic Diseases. Curr Neuropharmacol 2022; 20:662-674. [PMID: 33882809 PMCID: PMC9878956 DOI: 10.2174/1570159x19666210421094204] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/10/2021] [Accepted: 04/16/2021] [Indexed: 11/22/2022] Open
Abstract
Uncoupling protein 2 (UCP2) is a mitochondrial protein that acts as an anion carrier. It is involved in the regulation of several processes, including mitochondrial membrane potential, generation of reactive oxygen species within the inner mitochondrial membrane and calcium homeostasis. UCP2 expression can be regulated at different levels: genetic (gene variants), transcriptional [by peroxisome proliferator-activated receptors (PPARs) and microRNAs], and post-translational. Experimental evidence indicates that activation of UCP2 expression through the AMPK/PPAR-α axis exerts a protective effect toward renal damage and stroke occurrence in an animal model of ischemic stroke (IS) associated with hypertension. UCP2 plays a key role in heart diseases (myocardial infarction and cardiac hypertrophy) and metabolic disorders (obesity and diabetes). In humans, UCP2 genetic variants (-866G/A and Ala55Val) associate with an increased risk of type 2 diabetes mellitus and IS development. Over the last few years, many agents that modulate UCP2 expression have been identified. Some of them are natural compounds of plant origin, such as Brassica oleracea, curcumin, berberine and resveratrol. Other molecules, currently used in clinical practice, include anti-diabetic (gliptin) and chemotherapeutic (doxorubicin and taxol) drugs. This evidence highlights the relevant role of UCP2 for the treatment of a wide range of diseases, which affect the national health systems of Western countries. We will review current knowledge on the physiological and pathological implications of UCP2 with particular regard to cardiovascular and metabolic disorders and will focus on the available therapeutic approaches affecting UCP2 level for the treatment of human diseases.
Collapse
Affiliation(s)
- Rosita Stanzione
- IRCCS Neuromed, Pozzilli Isernia, Italy,,Address correspondence to these authors at the IRCCS Neuromed, Località Camerelle, 86077 Pozzilli, Is, Italy; Tel: +390865915224/23; Fax: +390865927575; E-mail: and Clinical and Molecular Medicine Department, School of Medicine and Psychology, Sapienza University of Rome, Ospedale S.Andrea, 00189 Rome, Italy; Tel: +390865915224/23; Fax: +390865927575; E-mail:
| | | | | | | | | | | | - Francesco Fornai
- IRCCS Neuromed, Pozzilli Isernia, Italy,,Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Speranza Rubattu
- IRCCS Neuromed, Pozzilli Isernia, Italy,,Department of Clinical and Molecular Medicine, School of Medicine and Psychology, Sapienza University of Rome, Rome, Italy,Address correspondence to these authors at the IRCCS Neuromed, Località Camerelle, 86077 Pozzilli, Is, Italy; Tel: +390865915224/23; Fax: +390865927575; E-mail: and Clinical and Molecular Medicine Department, School of Medicine and Psychology, Sapienza University of Rome, Ospedale S.Andrea, 00189 Rome, Italy; Tel: +390865915224/23; Fax: +390865927575; E-mail:
| |
Collapse
|
5
|
Huang L, Ma Y, Chen L, Chang J, Zhong M, Wang Z, Sun Y, Chen X, Sun F, Xiao L, Chen J, Lai Y, Yan C, Yue X. Maternal RND3/RhoE deficiency impairs placental mitochondrial function in preeclampsia by modulating the PPARγ-UCP2 cascade. FASEB J 2021; 35:e21555. [PMID: 34046947 DOI: 10.1096/fj.202002639rrr] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 03/03/2021] [Accepted: 03/08/2021] [Indexed: 12/25/2022]
Abstract
Preeclampsia (PE) is a life-threatening disease of pregnant women associated with severe hypertension, proteinuria, or multi-organ injuries. Mitochondrial-mediated placental oxidative stress plays a key role in the pathogenesis of PE. However, the underlying mechanism remains to be revealed. Here, we identify Rnd3, a small Rho GTPase, regulating placental mitochondrial reactive oxygen species (ROS). We showed that Rnd3 is down-regulated in primary trophoblasts isolated from PE patients. Loss of Rnd3 in trophoblasts resulted in excessive ROS generation, cell apoptosis, mitochondrial injury, and proton leakage from the respiratory chain. Moreover, Rnd3 overexpression partially rescues the mitochondrial defects and oxidative stress in human PE primary trophoblasts. Rnd3 physically interacts with the peroxisome proliferators-activated receptor γ (PPARγ) and promotes the PPARγ-mitochondrial uncoupling protein 2 (UCP2) cascade. Forced expression of PPARγ rescues deficiency of Rnd3-mediated mitochondrial dysfunction. We conclude that Rnd3 acts as a novel protective factor in placental mitochondria through PPARγ-UCP2 signaling and highlight that downregulation of Rnd3 is a potential factor involved in PE pathogenesis.
Collapse
Affiliation(s)
- Liping Huang
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yanlin Ma
- Hainan Provincial Key Laboratory for Human Reproductive Medicine and Genetic Research, Reproductive Medical Center, The First Affiliated Hospital of Hainan Medical University, Hainan Medical University, Haikou, China
| | - Lu Chen
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jiang Chang
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA
| | - Mei Zhong
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhijian Wang
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Ying Sun
- Department of Obstetrics and Gynecology, Affiliated Shenzhen Maternity and Child Healthcare Hospital, Southern Medical University, Shenzhen, China
| | - Xia Chen
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Fei Sun
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Lu Xiao
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jianing Chen
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yingjun Lai
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Chuming Yan
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaojing Yue
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| |
Collapse
|
6
|
Zhang Y, Bobe G, Miranda CL, Lowry MB, Hsu VL, Lohr CV, Wong CP, Jump DB, Robinson MM, Sharpton TJ, Maier CS, Stevens JF, Gombart AF. Tetrahydroxanthohumol, a xanthohumol derivative, attenuates high-fat diet-induced hepatic steatosis by antagonizing PPARγ. eLife 2021; 10:e66398. [PMID: 34128467 PMCID: PMC8205491 DOI: 10.7554/elife.66398] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 05/18/2021] [Indexed: 12/13/2022] Open
Abstract
We previously reported xanthohumol (XN), and its synthetic derivative tetrahydro-XN (TXN), attenuates high-fat diet (HFD)-induced obesity and metabolic syndrome in C57Bl/6J mice. The objective of the current study was to determine the effect of XN and TXN on lipid accumulation in the liver. Non-supplemented mice were unable to adapt their caloric intake to 60% HFD, resulting in obesity and hepatic steatosis; however, TXN reduced weight gain and decreased hepatic steatosis. Liver transcriptomics indicated that TXN might antagonize lipogenic PPARγ actions in vivo. XN and TXN inhibited rosiglitazone-induced 3T3-L1 cell differentiation concomitant with decreased expression of lipogenesis-related genes. A peroxisome proliferator activated receptor gamma (PPARγ) competitive binding assay showed that XN and TXN bind to PPARγ with an IC50 similar to pioglitazone and 8-10 times stronger than oleate. Molecular docking simulations demonstrated that XN and TXN bind in the PPARγ ligand-binding domain pocket. Our findings are consistent with XN and TXN acting as antagonists of PPARγ.
Collapse
Affiliation(s)
- Yang Zhang
- School of Biological and Population Health Sciences, Nutrition Program, Linus Pauling Institute, Oregon State UniversityCorvallisUnited States
| | - Gerd Bobe
- Department of Animal Sciences, Linus Pauling Institute, Oregon State UniversityCorvallisUnited States
| | - Cristobal L Miranda
- Department of Pharmaceutical Sciences, Linus Pauling Institute, Oregon State UniversityCorvallisUnited States
| | - Malcolm B Lowry
- Department of Microbiology, Oregon State UniversityCorvallisUnited States
| | - Victor L Hsu
- Department of Biochemistry and Biophysics, Oregon State UniversityCorvallisUnited States
| | - Christiane V Lohr
- Department of Biomedical Science, Carlson College of Veterinary MedicineCorvallisUnited States
| | - Carmen P Wong
- School of Biological and Population Health Sciences, Nutrition Program, Linus Pauling Institute, Oregon State UniversityCorvallisUnited States
| | - Donald B Jump
- School of Biological and Population Health Sciences, Nutrition Program, Linus Pauling Institute, Oregon State UniversityCorvallisUnited States
| | - Matthew M Robinson
- School of Biological and Population Health Sciences, Kinesiology Program, Oregon State UniversityCorvallisUnited States
| | - Thomas J Sharpton
- Department of Microbiology, Department of Statistics, Oregon State UniversityCorvallisUnited States
| | - Claudia S Maier
- Department of Chemistry, Linus Pauling Institute, Oregon State UniversityCorvallisUnited States
| | - Jan F Stevens
- Department of Pharmaceutical Sciences, Linus Pauling Institute, Oregon State UniversityCorvallisUnited States
| | - Adrian F Gombart
- Linus Pauling Institute, Department of Biochemistry and Biophysics, Oregon State UniversityCorvallisUnited States
| |
Collapse
|
7
|
van Dierendonck XAMH, Sancerni T, Alves-Guerra MC, Stienstra R. The role of uncoupling protein 2 in macrophages and its impact on obesity-induced adipose tissue inflammation and insulin resistance. J Biol Chem 2021; 295:17535-17548. [PMID: 33453996 DOI: 10.1074/jbc.ra120.014868] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/07/2020] [Indexed: 12/22/2022] Open
Abstract
The development of a chronic, low-grade inflammation originating from adipose tissue in obese subjects is widely recognized to induce insulin resistance, leading to the development of type 2 diabetes. The adipose tissue microenvironment drives specific metabolic reprogramming of adipose tissue macrophages, contributing to the induction of tissue inflammation. Uncoupling protein 2 (UCP2), a mitochondrial anion carrier, is thought to separately modulate inflammatory and metabolic processes in macrophages and is up-regulated in macrophages in the context of obesity and diabetes. Here, we investigate the role of UCP2 in macrophage activation in the context of obesity-induced adipose tissue inflammation and insulin resistance. Using a myeloid-specific knockout of UCP2 (Ucp2ΔLysM), we found that UCP2 deficiency significantly increases glycolysis and oxidative respiration, both unstimulated and after inflammatory conditions. Strikingly, fatty acid loading abolished the metabolic differences between Ucp2ΔLysM macrophages and their floxed controls. Furthermore, Ucp2ΔLysM macrophages show attenuated pro-inflammatory responses toward Toll-like receptor-2 and -4 stimulation. To test the relevance of macrophage-specific Ucp2 deletion in vivo, Ucp2ΔLysM and Ucp2fl/fl mice were rendered obese and insulin resistant through high-fat feeding. Although no differences in adipose tissue inflammation or insulin resistance was found between the two genotypes, adipose tissue macrophages isolated from diet-induced obese Ucp2ΔLysM mice showed decreased TNFα secretion after ex vivo lipopolysaccharide stimulation compared with their Ucp2fl/fl littermates. Together, these results demonstrate that although UCP2 regulates both metabolism and the inflammatory response of macrophages, its activity is not crucial in shaping macrophage activation in the adipose tissue during obesity-induced insulin resistance.
Collapse
Affiliation(s)
- Xanthe A M H van Dierendonck
- Nutrition, Metabolism, and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Wageningen, The Netherlands; Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | | | | | - Rinke Stienstra
- Nutrition, Metabolism, and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Wageningen, The Netherlands; Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
| |
Collapse
|
8
|
Hass DT, Barnstable CJ. Uncoupling proteins in the mitochondrial defense against oxidative stress. Prog Retin Eye Res 2021; 83:100941. [PMID: 33422637 DOI: 10.1016/j.preteyeres.2021.100941] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/28/2020] [Accepted: 01/03/2021] [Indexed: 02/06/2023]
Abstract
Oxidative stress is a major component of most major retinal diseases. Many extrinsic anti-oxidative strategies have been insufficient at counteracting one of the predominant intrinsic sources of reactive oxygen species (ROS), mitochondria. The proton gradient across the inner mitochondrial membrane is a key driving force for mitochondrial ROS production, and this gradient can be modulated by members of the mitochondrial uncoupling protein (UCP) family. Of the UCPs, UCP2 shows a widespread distribution and has been shown to uncouple oxidative phosphorylation, with concomitant decreases in ROS production. Genetic studies using transgenic and knockout mice have documented the ability of increased UCP2 activity to provide neuroprotection in models of a number of diseases, including retinal diseases, indicating that it is a strong candidate for a therapeutic target. Molecular studies have identified the structural mechanism of action of UCP2 and have detailed the ways in which its expression and activity can be controlled at the transcriptional, translational and posttranslational levels. These studies suggest a number of ways in control of UCP2 expression and activity can be used therapeutically for both acute and chronic conditions. The development of such therapeutic approaches will greatly increase the tools available to combat a broad range of serious retinal diseases.
Collapse
Affiliation(s)
- Daniel T Hass
- Department of Biochemistry, The University of Washington, Seattle, WA, 98109, USA
| | - Colin J Barnstable
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, 17033, USA.
| |
Collapse
|
9
|
Michel LYM, Farah C, Balligand JL. The Beta3 Adrenergic Receptor in Healthy and Pathological Cardiovascular Tissues. Cells 2020; 9:cells9122584. [PMID: 33276630 PMCID: PMC7761574 DOI: 10.3390/cells9122584] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 12/15/2022] Open
Abstract
The third isotype of beta-adrenoreceptors (β3-AR) has recently come (back) into focus after the observation of its expression in white and beige human adipocytes and its implication in metabolic regulation. This coincides with the recent development and marketing of agonists at the human receptor with superior specificity. Twenty years ago, however, we and others described the expression of β3-AR in human myocardium and its regulation of contractility and cardiac remodeling. Subsequent work from many laboratories has since expanded the characterization of β3-AR involvement in many aspects of cardiovascular physio(patho)logy, justifying the present effort to update current paradigms under the light of the most recent evidence.
Collapse
Affiliation(s)
- Lauriane Y. M. Michel
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Experimentale et Clinique (IREC), Université Catholique de Louvain, B1.57.04, 57 Avenue Hippocrate, 1200 Brussels, Belgium; (L.Y.M.M.); (C.F.)
| | - Charlotte Farah
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Experimentale et Clinique (IREC), Université Catholique de Louvain, B1.57.04, 57 Avenue Hippocrate, 1200 Brussels, Belgium; (L.Y.M.M.); (C.F.)
| | - Jean-Luc Balligand
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Experimentale et Clinique (IREC), Université Catholique de Louvain, B1.57.04, 57 Avenue Hippocrate, 1200 Brussels, Belgium; (L.Y.M.M.); (C.F.)
- Department of Medicine, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, 10 Avenue Hippocrate, 1200 Brussels, Belgium
- Correspondence: ; Tel.: +32-27645262
| |
Collapse
|
10
|
Abd Eldaim MA, Zhao K, Murakami M, Yoshioka H, Itoyama E, Kitamura S, Nagase H, Matsui T, Funaba M. Regulatory expression of uncoupling protein 1 and its related genes by endogenous activity of the transforming growth factor-β family in bovine myogenic cells. Cell Biochem Funct 2020; 39:116-125. [PMID: 33006416 DOI: 10.1002/cbf.3592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 08/27/2020] [Accepted: 09/14/2020] [Indexed: 02/06/2023]
Abstract
Uncoupling protein 1 (UCP1) is responsible for non-shivering thermogenesis, with restricted expression in brown/beige adipocytes in humans and rodents. We have previously shown an unexpected expression of UCP1 in bovine skeletal muscles. This study evaluated factors affecting Ucp1 gene expression in cultured bovine myogenic cells. Myosatellite cells, which were isolated from the bovine musculus longissimus cervicis, were induced to differentiate into myotubes in the presence of 2% horse serum. Previous studies using murine brown/beige adipocytes revealed that Ucp1 expression levels are directly increased by forskolin and all-trans retinoic acid (RA). The transforming growth factor-β (TGF-β)/activin pathway negatively regulated Ucp1 expression, whereas activation of the bone morphogenetic protein (BMP) pathway indirectly increases Ucp1 expression through the stimulation of brown/beige adipogenesis. Neither forskolin nor RA significantly affected Ucp1 mRNA levels in bovine myogenic cells. A-83-01, an inhibitor of the TGF-β/activin pathway, stimulated myogenesis in these cells. A-83-01 significantly increased the expression of some brown fat signature genes such as Pgc-1α, Cox7a1, and Dio2, with a quantitative but not significant increase in the expression of Ucp1. Treatment with LDN-193189, an inhibitor of the BMP pathway, did not affect the differentiation of bovine myosatellite cells. Rather, LDN-193189 increased Ucp1 mRNA levels without modulating the levels of other brown/beige adipocyte-related genes. The current results indicate that the regulation of Ucp1 expression in bovine myogenic cells is distinct from that in murine brown/beige adipocytes, which has been more intensely characterized. SIGNIFICANCE OF THE STUDY: We previously reported unexpected expression of Ucp1 in bovine muscle tissues; Ucp1 expression has been known to be detected predominantly in brown/beige adipocytes. This study examined regulatory expression of bovine Ucp1 in myogenic cells. Consistent with the changes in expression levels of brown/beige adipocyte-selective genes, Ucp1 expression tended to be increased by inhibition of endogenous TGF-β activity. In contrast, inhibition of endogenous BMP significantly increased Ucp1 expression without affecting brown/beige adipocyte-selective gene expression. The current results indicate that regulatory expression of Ucp1 in bovine myogenic cells is distinct from that in murine brown/beige adipocytes that is more intensely characterized.
Collapse
Affiliation(s)
- Mabrouk A Abd Eldaim
- Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.,Department of Biochemistry and Chemistry of Nutrition, Faculty of Veterinary Medicine, Menoufia University, Menoufia, Egypt
| | - Kangning Zhao
- Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Masaru Murakami
- Laboratory of Molecular Biology, Azabu University School of Veterinary Medicine, Sagamihara, Japan
| | | | | | | | | | - Tohru Matsui
- Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.,Kyoto University Livestock Farm, Japan
| | - Masayuki Funaba
- Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| |
Collapse
|
11
|
Yamada H, Munetsuna E, Yamazaki M, Mizuno G, Sadamoto N, Ando Y, Fujii R, Shiogama K, Ishikawa H, Suzuki K, Shimono Y, Ohashi K, Hashimoto S. Maternal fructose–induced oxidative stress occurs
via Tfam
and
Ucp5
epigenetic regulation in offspring hippocampi. FASEB J 2019; 33:11431-11442. [DOI: 10.1096/fj.201901072r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Hiroya Yamada
- Department of HygieneFujita Health UniversityToyoakeJapan
| | - Eiji Munetsuna
- Department of BiochemistryFujita Health UniversityToyoakeJapan
| | - Mirai Yamazaki
- Department of Clinical BiochemistryFujita Health UniversityToyoakeJapan
- Department of Medical TechnologyKagawa Prefectural University of Health SciencesTakamatsuJapan
| | - Genki Mizuno
- Joint Research Laboratory of Clinical MedicineFujita Health UniversityToyoakeJapan
| | - Nao Sadamoto
- Department of Clinical BiochemistryFujita Health UniversityToyoakeJapan
| | - Yoshitaka Ando
- Department of Clinical BiochemistryFujita Health UniversityToyoakeJapan
| | - Ryosuke Fujii
- Department of Preventive Medical SciencesFujita Health UniversityToyoakeJapan
| | - Kazuya Shiogama
- Department of Clinical ExaminationFujita Health University School of Medical SciencesFujita Health UniversityToyoakeJapan
| | - Hiroaki Ishikawa
- Department of Clinical BiochemistryFujita Health UniversityToyoakeJapan
| | - Koji Suzuki
- Department of Preventive Medical SciencesFujita Health UniversityToyoakeJapan
| | - Yohei Shimono
- Department of BiochemistryFujita Health UniversityToyoakeJapan
| | - Koji Ohashi
- Department of Clinical BiochemistryFujita Health UniversityToyoakeJapan
| | | |
Collapse
|
12
|
Hass DT, Barnstable CJ. Cell Autonomous Neuroprotection by the Mitochondrial Uncoupling Protein 2 in a Mouse Model of Glaucoma. Front Neurosci 2019; 13:201. [PMID: 30906248 PMCID: PMC6418046 DOI: 10.3389/fnins.2019.00201] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 02/20/2019] [Indexed: 12/20/2022] Open
Abstract
Glaucoma is a group of disorders associated with retinal ganglion cell (RGC) degeneration and death. There is a clear contribution of mitochondrial dysfunction and oxidative stress toward glaucomatous RGC death. Mitochondrial uncoupling protein 2 (Ucp2) is a well-known regulator of oxidative stress that increases cell survival in acute models of oxidative damage. The impact of Ucp2 on cell survival during sub-acute and chronic neurodegenerative conditions, however, is not yet clear. Herein, we test the hypothesis that increased Ucp2 expression will improve RGC survival in a mouse model of glaucoma. We show that increasing RGC but not glial Ucp2 expression in transgenic animals decreases glaucomatous RGC death, but also that the PPAR-γ agonist rosiglitazone (RSG), an endogenous transcriptional activator of Ucp2, does not significantly alter RGC loss during glaucoma. Together, these data support a model whereby increased Ucp2 expression mediates neuroprotection during a long-term oxidative stressor, but that transcriptional activation alone is insufficient to elicit a neuroprotective effect, motivating further research in to the post-transcriptional regulation of Ucp2.
Collapse
Affiliation(s)
- Daniel T Hass
- Department of Neural and Behavioral Sciences, College of Medicine, The Pennsylvania State University, Hershey, PA, United States
| | - Colin J Barnstable
- Department of Neural and Behavioral Sciences, College of Medicine, The Pennsylvania State University, Hershey, PA, United States
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Tian XY, Ma S, Tse G, Wong WT, Huang Y. Uncoupling Protein 2 in Cardiovascular Health and Disease. Front Physiol 2018; 9:1060. [PMID: 30116205 PMCID: PMC6082951 DOI: 10.3389/fphys.2018.01060] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 07/16/2018] [Indexed: 12/22/2022] Open
Abstract
Uncoupling protein 2 (UCP2) belongs to the family of mitochondrial anion carrier proteins. It uncouples oxygen consumption from ATP synthesis. UCP2 is ubiquitously expressed in most cell types to reduce oxidative stress. It is tightly regulated at the transcriptional, translational, and post-translational levels. UCP2 in the cardiovascular system is being increasingly recognized as an important molecule to defend against various stress signals such as oxidative stress in the pathology of vascular dysfunction, atherosclerosis, hypertension, and cardiac injuries. UCP2 protects against cellular dysfunction through reducing mitochondrial oxidative stress and modulation of mitochondrial function. In view of the different functions of UCP2 in various cell types that contribute to whole body homeostasis, cell type-specific modification of UCP2 expression may offer a better approach to help understanding how UCP2 governs mitochondrial function, reactive oxygen species production and transmembrane proton leak and how dysfunction of UCP2 participates in the development of cardiovascular diseases. This review article provided an update on the physiological regulation of UCP2 in the cardiovascular system, and also discussed the involvement of UCP2 deficiency and associated oxidative stress in the pathogenesis of several common cardiovascular diseases. Drugs targeting UCP2 expression and activity might serve another effective strategy to ameliorate cardiovascular dysfunction. However, more detailed mechanistic study will be needed to dissect the role of UCP2, the regulation of UCP2 expression, and the cellular responses to the changes of UCP2 expression in normal and stressed situations at different stages of cardiovascular diseases.
Collapse
Affiliation(s)
- Xiao Yu Tian
- School of Biomedical Sciences, Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Shuangtao Ma
- Division of Nanomedicine and Molecular Intervention, Department of Medicine, Michigan State University, East Lansing, MI, United States
| | - Gary Tse
- Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Wing Tak Wong
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yu Huang
- School of Biomedical Sciences, Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| |
Collapse
|
15
|
Abstract
The hypermetabolic effects of thyroid hormones (THs), the major endocrine regulators of metabolic rate, are widely recognized. Although, the cellular mechanisms underlying these effects have been extensively investigated, much has yet to be learned about how TH regulates diverse cellular functions. THs have a profound impact on mitochondria, the organelles responsible for the majority of cellular energy production, and several studies have been devoted to understand the respective importance of the nuclear and mitochondrial pathways for organelle activity. During the last decades, several new aspects of both THs (i.e., metabolism, transport, mechanisms of action, and the existence of metabolically active TH derivatives) and mitochondria (i.e., dynamics, respiratory chain organization in supercomplexes, and the discovery of uncoupling proteins other than uncoupling protein 1) have emerged, thus opening new perspectives to the investigation of the complex relationship between thyroid and the mitochondrial compartment. In this review, in the light of an historical background, we attempt to point out the present findings regarding thyroid physiology and the emerging recognition that mitochondrial dynamics as well as the arrangement of the electron transport chain in mitochondrial cristae contribute to the mitochondrial activity. We unravel the genomic and nongenomic mechanisms so far studied as well as the effects of THs on mitochondrial energetics and, principally, uncoupling of oxidative phosphorylation via various mechanisms involving uncoupling proteins. The emergence of new approaches to the question as to what extent and how the action of TH can affect mitochondria is highlighted. © 2016 American Physiological Society. Compr Physiol 6:1591-1607, 2016.
Collapse
Affiliation(s)
- Antonia Lanni
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università degli Studi di Napoli, Caserta, Italy
| | - Maria Moreno
- Dipartimento di Scienze e Tecnologie, Università degli Studi del Sannio, Benevento, Italy
| | - Fernando Goglia
- Dipartimento di Scienze e Tecnologie, Università degli Studi del Sannio, Benevento, Italy
| |
Collapse
|
16
|
Zhou Y, Zhang MJ, Li BH, Chen L, Pi Y, Yin YW, Long CY, Wang X, Sun MJ, Chen X, Gao CY, Li JC, Zhang LL. PPARγ Inhibits VSMC Proliferation and Migration via Attenuating Oxidative Stress through Upregulating UCP2. PLoS One 2016; 11:e0154720. [PMID: 27144886 PMCID: PMC4856345 DOI: 10.1371/journal.pone.0154720] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Accepted: 04/18/2016] [Indexed: 01/20/2023] Open
Abstract
Increasing evidence showed that abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) are common event in the pathophysiology of many vascular diseases, including atherosclerosis and restenosis after angioplasty. Among the underlying mechanisms, oxidative stress is one of the principal contributors to the proliferation and migration of VSMCs. Oxidative stress occurs as a result of persistent production of reactive oxygen species (ROS). Recently, the protective effects of peroxisome proliferator-activated receptor γ (PPARγ) against oxidative stress/ROS in other cell types provide new insights to inhibit the suggests that PPARγ may regulate VSMCs function. However, it remains unclear whether activation of PPARγ can attenuate oxidative stress and further inhibit VSMC proliferation and migration. In this study, we therefore investigated the effect of PPARγ on inhibiting VSMC oxidative stress and the capability of proliferation and migration, and the potential role of mitochondrial uncoupling protein 2 (UCP2) in oxidative stress. It was found that platelet derived growth factor-BB (PDGF-BB) induced VSMC proliferation and migration as well as ROS production; PPARγ inhibited PDGF-BB-induced VSMC proliferation, migration and oxidative stress; PPARγ activation upregulated UCP2 expression in VSMCs; PPARγ inhibited PDGF-BB-induced ROS in VSMCs by upregulating UCP2 expression; PPARγ ameliorated injury-induced oxidative stress and intimal hyperplasia (IH) in UCP2-dependent manner. In conclusion, our study provides evidence that activation of PPARγ can attenuate ROS and VSMC proliferation and migration by upregulating UCP2 expression, and thus inhibit IH following carotid injury. These findings suggest PPARγ may represent a prospective target for the prevention and treatment of IH-associated vascular diseases.
Collapse
Affiliation(s)
- Yi Zhou
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Ming-Jie Zhang
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Bing-Hu Li
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Lei Chen
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Yan Pi
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Yan-Wei Yin
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Chun-Yan Long
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Xu Wang
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Meng-Jiao Sun
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Xue Chen
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Chang-Yue Gao
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Jing-Cheng Li
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
- * E-mail: (L-LZ); (J-CL)
| | - Li-Li Zhang
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
- * E-mail: (L-LZ); (J-CL)
| |
Collapse
|
17
|
UCPs, at the interface between bioenergetics and metabolism. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2443-56. [PMID: 27091404 DOI: 10.1016/j.bbamcr.2016.04.013] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 01/25/2023]
Abstract
The first member of the uncoupling protein (UCP) family, brown adipose tissue uncoupling protein 1 (UCP1), was identified in 1976. Twenty years later, two closely related proteins, UCP2 and UCP3, were described in mammals. Homologs of these proteins exist in other organisms, including plants. Uncoupling refers to a deterioration of energy conservation between substrate oxidation and ADP phosphorylation. Complete energy conservation loss would be fatal but fine-tuning can be beneficial for processes such as thermogenesis, redox control, and prevention of mitochondrial ROS release. The coupled/uncoupled state of mitochondria is related to the permeability of the inner membrane and the proton transport mediated by activated UCPs underlies the uncoupling activity of these proteins. Proton transport by UCP1 is activated by fatty acids and this ensures thermogenesis. In vivo in absence of this activation UCP1 remains inhibited with no transport activity. A similar situation now seems unlikely for UCP2 and UCP3 and while activation of their proton transport has been described its physiological relevance remains uncertain and their influence can be envisaged as a result of another transport pathway that takes place in the absence of activation. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
Collapse
|
18
|
Uncoupling protein 2 regulates palmitic acid-induced hepatoma cell autophagy. BIOMED RESEARCH INTERNATIONAL 2014; 2014:810401. [PMID: 25512910 PMCID: PMC4143590 DOI: 10.1155/2014/810401] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 06/29/2014] [Accepted: 06/30/2014] [Indexed: 01/11/2023]
Abstract
Mitochondrial uncoupling protein 2 (UCP2) is suggested to have a role in the development of nonalcoholic steatohepatitis (NASH). However, the mechanism remains unclear. Autophagy is an important mediator of many pathological responses. This study aims to investigate the relationship between UCP2 and hepatoma cells autophagy in palmitic acid- (PA-) induced lipotoxicity. H4IIE cells were treated with palmitic acid (PA), and cell autophagy and apoptosis were examined. UCP2 expression, in association with LC3-II and caspase-3, which are indicators of cell autophagy and apoptosis, respectively,was measured. Results demonstrated that UCP2 was associated with autophagy during PA-induced hepatic carcinoma cells injury. Tests on reactive oxygen species (ROS) showed that UCP2 overexpression strongly decreases PA-induced ROS production and apoptosis. Conversely, UCP2 inhibition by genipin or UCP2 mRNA silencing enhances PA-induced ROS production and apoptosis. Autophagy partially participates in this progress. Moreover, UCP2 was associated with ATP synthesis during PA-induced autophagy. In conclusion, increasing UCP2 expression in hepatoma cells may contribute to cell autophagy and antiapoptotic as result of fatty acid injury. Our results may bring new insights for potential NASH therapies.
Collapse
|
19
|
Donadelli M, Dando I, Fiorini C, Palmieri M. UCP2, a mitochondrial protein regulated at multiple levels. Cell Mol Life Sci 2014; 71:1171-90. [PMID: 23807210 PMCID: PMC11114077 DOI: 10.1007/s00018-013-1407-0] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 05/16/2013] [Accepted: 06/10/2013] [Indexed: 12/11/2022]
Abstract
An ever-increasing number of studies highlight the role of uncoupling protein 2 (UCP2) in a broad range of physiological and pathological processes. The knowledge of the molecular mechanisms of UCP2 regulation is becoming fundamental in both the comprehension of UCP2-related physiological events and the identification of novel therapeutic strategies based on UCP2 modulation. The study of UCP2 regulation is a fast-moving field. Recently, several research groups have made a great effort to thoroughly understand the various molecular mechanisms at the basis of UCP2 regulation. In this review, we describe novel findings concerning events that can occur in a concerted manner at various levels: Ucp2 gene mutation (single nucleotide polymorphisms), UCP2 mRNA and protein expression (transcriptional, translational, and protein turn-over regulation), UCP2 proton conductance (ligands and post-transcriptional modifications), and nutritional and pharmacological regulation of UCP2.
Collapse
Affiliation(s)
- Massimo Donadelli
- Section of Biochemistry, Deparment of Life and Reproduction Sciences, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy,
| | | | | | | |
Collapse
|
20
|
Basu Ball W, Mukherjee M, Srivastav S, Das PK. Leishmania donovani activates uncoupling protein 2 transcription to suppress mitochondrial oxidative burst through differential modulation of SREBP2, Sp1 and USF1 transcription factors. Int J Biochem Cell Biol 2014; 48:66-76. [DOI: 10.1016/j.biocel.2014.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 01/03/2014] [Indexed: 11/28/2022]
|
21
|
Cheng G, Palanisamy AP, Evans ZP, Sutter AG, Jin L, Singh I, May H, Schmidt MG, Chavin KD. Cerulenin blockade of fatty acid synthase reverses hepatic steatosis in ob/ob mice. PLoS One 2013; 8:e75980. [PMID: 24086674 PMCID: PMC3785413 DOI: 10.1371/journal.pone.0075980] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/18/2013] [Indexed: 12/14/2022] Open
Abstract
Fatty liver or hepatic steatosis is a common health problem associated with abnormal liver function and increased susceptibility to ischemia/reperfusion injury. The objective of this study was to investigate the effect of the fatty acid synthase inhibitor cerulenin on hepatic function in steatotic ob/ob mice. Different dosages of cerulenin were administered intraperitoneally to ob/ob mice for 2 to 7 days. Body weight, serum AST/ALT, hepatic energy state, and gene expression patterns in ob/ob mice were examined. We found that cerulenin treatment markedly improved hepatic function in ob/ob mice. Serum AST/ALT levels were significantly decreased and hepatic ATP levels increased in treated obese mice compared to obese controls, accompanied by fat depletion in the hepatocyte. Expression of peroxisome proliferator-activated receptors α and γ and uncoupling protein 2 were suppressed with cerulenin treatment and paralleled changes in AST/ALT levels. Hepatic glutathione content were increased in some cases and apoptotic activity in the steatotic livers was minimally changed with cerulenin treatment. In conclusion, these results demonstrate that fatty acid synthase blockade constitutes a novel therapeutic strategy for altering hepatic steatosis at non-stressed states in obese livers.
Collapse
Affiliation(s)
- Gang Cheng
- Divisions of Transplant Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Arun P. Palanisamy
- Divisions of Transplant Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail:
| | - Zachary P. Evans
- Divisions of Transplant Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Alton G. Sutter
- Divisions of Transplant Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Lan Jin
- Divisions of Transplant Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Inderjit Singh
- Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Harold May
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Michael G. Schmidt
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Kenneth D. Chavin
- Divisions of Transplant Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
| |
Collapse
|
22
|
Transcriptional Regulation of the Mitochondrial Citrate and Carnitine/Acylcarnitine Transporters: Two Genes Involved in Fatty Acid Biosynthesis and β-oxidation. BIOLOGY 2013; 2:284-303. [PMID: 24832661 PMCID: PMC4009865 DOI: 10.3390/biology2010284] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 01/18/2013] [Accepted: 01/23/2013] [Indexed: 12/17/2022]
Abstract
Transcriptional regulation of genes involved in fatty acid metabolism is considered the major long-term regulatory mechanism controlling lipid homeostasis. By means of this mechanism, transcription factors, nutrients, hormones and epigenetics control not only fatty acid metabolism, but also many metabolic pathways and cellular functions at the molecular level. The regulation of the expression of many genes at the level of their transcription has already been analyzed. This review focuses on the transcriptional control of two genes involved in fatty acid biosynthesis and oxidation: the citrate carrier (CIC) and the carnitine/ acylcarnitine/carrier (CAC), which are members of the mitochondrial carrier gene family, SLC25. The contribution of tissue-specific and less tissue-specific transcription factors in activating or repressing CIC and CAC gene expression is discussed. The interaction with drugs of some transcription factors, such as PPAR and FOXA1, and how this interaction can be an attractive therapeutic approach, has also been evaluated. Moreover, the mechanism by which the expression of the CIC and CAC genes is modulated by coordinated responses to hormonal and nutritional changes and to epigenetics is highlighted.
Collapse
|
23
|
Wu Y, Zhang C, Dong Y, Wang S, Song P, Viollet B, Zou MH. Activation of the AMP-activated protein kinase by eicosapentaenoic acid (EPA, 20:5 n-3) improves endothelial function in vivo. PLoS One 2012; 7:e35508. [PMID: 22532857 PMCID: PMC3330125 DOI: 10.1371/journal.pone.0035508] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 03/16/2012] [Indexed: 02/04/2023] Open
Abstract
The aim of the present study was to test the hypothesis that the cardiovascular-protective effects of eicosapentaenoic acid (EPA) may be due, in part, to its ability to stimulate the AMP-activated protein kinase (AMPK)-induced endothelial nitric oxide synthase (eNOS) activation. The role of AMPK in EPA-induced eNOS phosphorylation was investigated in bovine aortic endothelial cells (BAEC), in mice deficient of either AMPKα1 or AMPKα2, in eNOS knockout (KO) mice, or in Apo-E/AMPKα1 dual KO mice. EPA-treatment of BAEC increased both AMPK-Thr172 phosphorylation and AMPK activity, which was accompanied by increased eNOS phosphorylation, NO release, and upregulation of mitochondrial uncoupling protein-2 (UCP-2). Pharmacologic or genetic inhibition of AMPK abolished EPA-enhanced NO release and eNOS phosphorylation in HUVEC. This effect of EPA was absent in the aortas isolated from either eNOS KO mice or AMPKα1 KO mice fed a high-fat, high-cholesterol (HFHC) diet. EPA via upregulation of UCP-2 activates AMPKα1 resulting in increased eNOS phosphorylation and consequent improvement of endothelial function in vivo.
Collapse
Affiliation(s)
- Yong Wu
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, United States of America
| | - Cheng Zhang
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, United States of America
| | - Yunzhou Dong
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, United States of America
| | - Shuangxi Wang
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, United States of America
| | - Ping Song
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, United States of America
| | - Benoit Viollet
- Département de Génétique, Développement et Pathologie Moléculaire, Institut Cochin, Université René Descartes Paris 5, Institut National de la Santé et de la Recherche Medicale U567, Centre National de la Recherchè Scientifique UMR8104, Paris, France
| | - Ming-Hui Zou
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
| |
Collapse
|
24
|
Villarroya F, Iglesias R, Giralt M. PPARs in the Control of Uncoupling Proteins Gene Expression. PPAR Res 2011; 2007:74364. [PMID: 17389766 PMCID: PMC1779581 DOI: 10.1155/2007/74364] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 10/18/2006] [Accepted: 10/18/2006] [Indexed: 11/17/2022] Open
Abstract
Uncoupling proteins (UCPs) are mitochondrial membrane transporters involved in the control of energy conversion in mitochondria. Experimental and genetic evidence relate dysfunctions of UCPs with metabolic syndrome and obesity. The PPAR subtypes mediate to a large extent the transcriptional regulation of the UCP genes, with a distinct relevance depending on the UCP gene and the tissue in which it is expressed. UCP1 gene is under the dual control of PPARγ and PPARα in relation to brown adipocyte differentiation and lipid oxidation, respectively. UCP3 gene is regulated by PPARα and PPARδ in the muscle, heart, and adipose tissues. UCP2 gene is also under the control of PPARs even in tissues in which it is the predominantly expressed UCP (eg, the pancreas and liver). This review summarizes the current understanding of the role of PPARs in UCPs gene expression in normal conditions and also in the context of type-2 diabetes or obesity.
Collapse
Affiliation(s)
- Francesc Villarroya
- Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona 585 08007, Spain
- *Francesc Villarroya:
| | - Roser Iglesias
- Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona 585 08007, Spain
| | - Marta Giralt
- Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona 585 08007, Spain
| |
Collapse
|
25
|
Han YX, Lin YT, Xu JJ, Cao LL, Liu XW, Jiang H, Chi ZF. Status epilepticus stimulates peroxisome proliferator-activated receptor γ coactivator 1-α/mitochondrial antioxidant system pathway by a nitric oxide-dependent mechanism. Neuroscience 2011; 186:128-34. [PMID: 21536107 DOI: 10.1016/j.neuroscience.2011.04.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 04/07/2011] [Accepted: 04/08/2011] [Indexed: 12/26/2022]
Abstract
Peroxisome proliferator-activated receptor (PPAR) γ coactivator 1-α (PGC-1α) is a transcriptional coactivator identified as an upstream regulator of lipid catabolism, mitochondrial number and function. PGC-1α protects neurons against oxidative damage by inducing several members of the mitochondrial antioxidant system such as superoxide dismutase 2 (SOD2) and uncoupling protein 2 (UCP2). Its role in seizure-induced oxidative stress has not been studied. Here we showed that pilocarpine-induced status epilepticus (SE) stimulates the PGC-1α/mitochondrial antioxidant system signaling pathway in the rat hippocampus. Because nitric oxide (NO) is the key factor of mitochondrial biogenesis through the transcriptional induction of PGC-1α, we investigated whether NO is involved in activation of the PGC-1α/mitochondrial antioxidant system after SE. Treatment with the NO synthase (NOS) inhibitor N(G)-nitro-l-argininemethyl ester (l-NAME) attenuated the increased expression of the PGC-1α/mitochondrial antioxidant system after SE and enhanced oxidative stress. These results suggest that SE can induce the PGC-1α/mitochondrial antioxidant system signaling pathway, which may represent a protective mechanism against SE-induced oxidative stress. Furthermore, NO may positively regulate the mitochondrial antioxidant system by inducing PGC-1α in pilocarpine-induced SE.
Collapse
Affiliation(s)
- Y X Han
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | | | | | | | | | | | | |
Collapse
|
26
|
Yang M, Huang Q, Wu J, Yin JY, Sun H, Liu HL, Zhou HH, Liu ZQ. Effects of UCP2 -866 G/A and ADRB3 Trp64Arg on rosiglitazone response in Chinese patients with Type 2 diabetes. Br J Clin Pharmacol 2010; 68:14-22. [PMID: 19659999 DOI: 10.1111/j.1365-2125.2009.03431.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
AIMS The aim of this study was to explore the impact of UCP2 and ADRB3 genetic polymorphisms on the therapeutic efficacy of rosiglitazone in Chinese Type 2 diabetes (T2DM) patients. METHODS A total of 199 T2DM patients and 155 healthy volunteers were enrolled to identify UCP2 -866 G/A genotypes, and 273 T2DM patients and 166 controls were genotyped for Trp64Arg of ADRB3 by polymerase chain reaction-restriction fragment length polymorphism assay. Nine patients with GG genotype and 27 with GA+AA genotype of UCP2 -866 G/A, 11 with Trp64Trp genotype and 25 with Trp64Arg genotype of ADRB3 received oral rosiglitazone as a single-agent therapy (4 mg day(-1)) for 12 weeks. Serum fasting plasma glucose, postprandial plasma glucose, glycated haemoglobin (HbA(1c)), fasting serum insulin, postprandial serum insulin (PINS), triglycerol (TG), cholesterol, homeostasis model assessment for insulin resistance, leptin and adiponectin in all T2DM patients were determined before and after rosiglitazone treatment. RESULTS There were no differences in allele frequency of either ADRB3 Trp64Arg or UCP2 -866 G/A between T2DM patients and control subjects. The A allele carriers of UCP2 in the T2DM patients had significantly lower PINS (61.5 +/- 34.3 vs. 41.6 +/- 28.7 mU l(-1), P < 0.01) (37.57, 59.16 vs. 34.82, 49.39) and low-density lipoprotein (LDL)-cholesterol compared with GG genotypes (3.4 +/- 1.1 vs. 2.7 +/- 1.1 mmol l(-1), P < 0.05) (2.64, 3.52 vs. 2.66, 3.15). After rosiglitazone treatment for 12 consecutive weeks, we found that A allele carriers of UCP2 in the T2DM patients had smaller attenuated PINS (-3.82 +/- 13.2 vs.-42.1 +/- 30.7 mU l(-1), P < 0.01) (9.45, 51.31 vs. 0.48, 11.88) and greater attenuated HbA(1c) (-1.85 +/- 1.62 vs.-0.61 +/- 0.80, P < 0.05) (0.14, 1.37 vs. 1.10, 2.38) compared with GG genotypes, and ADRB3 Trp64Arg had greater attenuated serum TG (-3.88 +/- 2.77 vs.-0.24 +/- 1.16 mmol l(-1), P < 0.05) (-0.19, 2.74 vs. 1.19, 1.45) and smaller attenuated LDL-cholesterol (1.08 +/- 1.36 vs.-0.36 +/- 0.99, P < 0.01) (-1.26, 0.78 vs.-1.26, 0.79) as well as reduced enhanced adiponectin (1.57 +/- 1.10 vs. 3.15 +/- 2.12 mmol l(-1), P < 0.05) (1.68, 4.08 vs.-9.18, 11.40) compared with ADRB3 Trp64Trp. CONCLUSION UCP2 -866 G/A and ADRB3 Trp64Arg polymorphisms are associated with the therapeutic efficacy of multiple-dose rosiglitazone in Chinese T2DM patients.
Collapse
Affiliation(s)
- Min Yang
- Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University Xiang-Ya School of Medicine, Changsha, Hunan, China
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Bugge A, Siersbaek M, Madsen MS, Göndör A, Rougier C, Mandrup S. A novel intronic peroxisome proliferator-activated receptor gamma enhancer in the uncoupling protein (UCP) 3 gene as a regulator of both UCP2 and -3 expression in adipocytes. J Biol Chem 2010; 285:17310-7. [PMID: 20360005 DOI: 10.1074/jbc.m110.120584] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Uncoupling Proteins (UCPs) are integral ion channels residing in the inner mitochondrial membrane. UCP2 is ubiquitously expressed, while UCP3 is found primarily in muscles and adipose tissue. Although the exact molecular mechanism of action is controversial, it is generally agreed that both homologues function to facilitate mitochondrial fatty acid oxidation. UCP2 and -3 expression is activated by the peroxisome proliferator-activated receptors (PPARs), but so far no PPAR response element has been reported in the vicinity of the Ucp2 and Ucp3 genes. Using genome-wide profiling of PPARgamma occupancy in 3T3-L1 adipocytes we demonstrate that PPARgamma associates with three chromosomal regions in the vicinity of the Ucp3 locus and weakly with a site in intron 1 of the Ucp2 gene. These sites are isolated from the nearest neighboring sites by >900 kb. The most prominent PPARgamma binding site in the Ucp2 and Ucp3 loci is located in intron 1 of the Ucp3 gene and is the only site that facilitates PPARgamma transactivation of a heterologous promoter. This site furthermore transactivates the endogenous Ucp3 promoter, and using chromatin conformation capture we show that it loops out to specifically interact with the Ucp2 promoter and intron 1. Our data indicate that PPARgamma transactivation of both UCP2 and -3 is mediated through this novel enhancer in Ucp3 intron 1.
Collapse
Affiliation(s)
- Anne Bugge
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | | | | | | | | | | |
Collapse
|
28
|
Yonezawa T, Kurata R, Hosomichi K, Kono A, Kimura M, Inoko H. Nutritional and hormonal regulation of uncoupling protein 2. IUBMB Life 2010; 61:1123-31. [PMID: 19946892 DOI: 10.1002/iub.264] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Uncoupling proteins (UCPs) belong to a family of mitochondrial carrier proteins that are present in the mitochondrial inner membrane. Genetic and experimental studies have shown that UCP dysfunction can be involved in metabolic disorders and in obesity. Uncoupling protein-1 (UCP1; also known as thermogenin) was identified in 1988 and found to be highly expressed in brown adipose tissue. UCP1 allows the leak of protons in respiring mitochondria, dissipating the energy as heat; the enzyme has an important role in nonshivering heat production induced by cold exposure or food intake. In 1997, two homologs of UCP1 were identified and named UCP2 and UCP3. These novel proteins also lower mitochondrial membrane potential, but whether they can dissipate metabolic energy as heat as efficiently as UCP1 is open to dispute. Even after a decade of study, the physiological roles of these novel proteins have still not been completely elucidated. This review aims to shed light on the nutritional and hormonal regulation of UCP2 and on its physiological roles.
Collapse
Affiliation(s)
- Tomo Yonezawa
- Division of Basic Molecular Science and Molecular Medicine, School of Medicine, Tokai University, Bohseidai, Ishehara, Kanagawa, Japan.
| | | | | | | | | | | |
Collapse
|
29
|
Baffy G. Uncoupling protein-2 and cancer. Mitochondrion 2009; 10:243-52. [PMID: 20005987 DOI: 10.1016/j.mito.2009.12.143] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 11/12/2009] [Accepted: 12/07/2009] [Indexed: 02/06/2023]
Abstract
Cancer cells respond to unfavorable microenvironments such as nutrient limitation, hypoxia, oxidative stress, and host defense by comprehensive metabolic reprogramming. Mitochondria are linked to this complex adaptive response and emerging evidence indicates that uncoupling protein-2 (UCP2), a mitochondrial inner membrane anion carrier, may contribute to this process. Effects of UCP2 on mitochondrial bioenergetics, redox homeostasis, and oxidant production in cancer cells may modulate molecular pathways of macromolecular biosynthesis, antioxidant defense, apoptosis, cell growth and proliferation, enhancing robustness and promoting chemoresistance. Elucidation of these interactions may identify novel anti-cancer strategies.
Collapse
Affiliation(s)
- Gyorgy Baffy
- VA Boston Healthcare System and Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
30
|
Pi J, Zhang Q, Fu J, Woods CG, Hou Y, Corkey BE, Collins S, Andersen ME. ROS signaling, oxidative stress and Nrf2 in pancreatic beta-cell function. Toxicol Appl Pharmacol 2009; 244:77-83. [PMID: 19501608 DOI: 10.1016/j.taap.2009.05.025] [Citation(s) in RCA: 248] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 05/22/2009] [Accepted: 05/27/2009] [Indexed: 12/16/2022]
Abstract
This review focuses on the emerging evidence that reactive oxygen species (ROS) derived from glucose metabolism, such as H(2)O(2), act as metabolic signaling molecules for glucose-stimulated insulin secretion (GSIS) in pancreatic beta-cells. Particular emphasis is placed on the potential inhibitory role of endogenous antioxidants, which rise in response to oxidative stress, in glucose-triggered ROS and GSIS. We propose that cellular adaptive response to oxidative stress challenge, such as nuclear factor E2-related factor 2 (Nrf2)-mediated antioxidant induction, plays paradoxical roles in pancreatic beta-cell function. On the one hand, induction of antioxidant enzymes protects beta-cells from oxidative damage and possible cell death, thus minimizing oxidative damage-related impairment of insulin secretion. On the other hand, the induction of antioxidant enzymes by Nrf2 activation blunts glucose-triggered ROS signaling, thus resulting in reduced GSIS. These two premises are potentially relevant to impairment of beta-cells occurring in the late and early stage of Type 2 diabetes, respectively. In addition, we summarized our recent findings that persistent oxidative stress due to absence of uncoupling protein 2 activates cellular adaptive response which is associated with impaired pancreatic beta-cell function.
Collapse
Affiliation(s)
- Jingbo Pi
- Division of Translational Biology, The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709, USA.
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Jiang Y, Zhang H, Dong LY, Wang D, An W. Increased hepatic UCP2 expression in rats with nonalcoholic steatohepatitis is associated with upregulation of Sp1 binding to its motif within the proximal promoter region. J Cell Biochem 2008; 105:277-89. [PMID: 18543254 DOI: 10.1002/jcb.21827] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Uncoupling protein-2 (UCP2) is a mitochondrial inner-membrane carrier protein that is involved in the control of fatty acid metabolism. To understand the mechanism of the transcriptional regulation of ucp2 in the pathogenesis of nonalcoholic steatohepatitis (NASH), we cloned 500 bp upstream of the ucp2 exon 1 from a rat liver cDNA library and identified cis-acting regulatory elements. The transcriptional start site was identified as "C," -359 bp from the ATG codon. A reporter gene assay showed that deletion of the nucleotide sequence between -264 and -60 bp resulted in a significant decrease in promoter activity in HepG2 and H4IIE cells. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) revealed that the increase in promoter activity is related to an enhanced ability of Sp1 to bind to its motifs at -84 to -61 bp within the ucp2 proximal promoter. Overexpression of exogenous Sp1 in H4IIE cells also increased the promoter activity. We demonstrated that the expression of UCP2 mRNA and protein is markedly increased in rats with nonalcoholic steatohepatitis (NASH). Coincidently, levels of Sp1 binding to -84/-61 bp were also increased. Overall, our data indicate that the Sp1-binding site located at the proximal promoter is involved in the regulation of rat UCP2 expression.
Collapse
Affiliation(s)
- Ying Jiang
- Department of Cell Biology and Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, 100069 Beijing, China
| | | | | | | | | |
Collapse
|
32
|
Wiggin TD, Kretzler M, Pennathur S, Sullivan KA, Brosius FC, Feldman EL. Rosiglitazone treatment reduces diabetic neuropathy in streptozotocin-treated DBA/2J mice. Endocrinology 2008; 149:4928-37. [PMID: 18583417 PMCID: PMC2582925 DOI: 10.1210/en.2008-0869] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Diabetic neuropathy (DN) is a common complication of diabetes. Currently, there is no drug treatment to prevent or slow the development of DN. Rosiglitazone (Rosi) is a potent insulin sensitizer and may also slow the development of DN by a mechanism independent of its effect on hyperglycemia. A two by two design was used to test the effect of Rosi treatment on the development of DN. Streptozotocin-induced diabetic DBA/2J mice were treated with Rosi. DN and oxidative stress were quantified, and gene expression was profiled using the Affymetrix Mouse Genome 430 2.0 microarray platform. An informatics approach identified key regulatory elements activated by Rosi. Diabetic DBA/2J mice developed severe hyperglycemia, DN, and elevated oxidative stress. Rosi treatment did not affect hyperglycemia but did reduce oxidative stress and prevented the development of thermal hypoalgesia. Two novel transcription factor binding modules were identified that may control genes correlated to changes in DN after Rosi treatment: SP1F_ZBPF and EGRF_EGRF. These targets may be useful in designing drugs with the same efficacy as Rosi in treating DN but with fewer undesirable effects.
Collapse
Affiliation(s)
- Timothy D Wiggin
- University of Michigan, Department of Neurology, 5017 Basic Science Research Building, 109 Zina Pitcher Road, Ann Arbor, Michigan 48109-2200, USA
| | | | | | | | | | | |
Collapse
|
33
|
SUMOylation of Krüppel-like transcription factor 5 acts as a molecular switch in transcriptional programs of lipid metabolism involving PPAR-delta. Nat Med 2008; 14:656-66. [PMID: 18500350 DOI: 10.1038/nm1756] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 03/20/2008] [Indexed: 01/17/2023]
Abstract
Obesity and metabolic syndrome are increasingly recognized as major risk factors for cardiovascular disease. Herein we show that Krüppel-like transcription factor 5 (KLF5) is a crucial regulator of energy metabolism. Klf5(+/-) mice were resistant to high fat-induced obesity, hypercholesterolemia and glucose intolerance, despite consuming more food than wild-type mice. This may in part reflect their enhanced energy expenditure. Expression of the genes involved in lipid oxidation and energy uncoupling, including those encoding carnitine-palmitoyl transferase-1b (Cpt1b) and uncoupling proteins 2 and 3 (Ucp2 and Ucp3), was upregulated in the soleus muscles of Klf5(+/-) mice. Under basal conditions, KLF5 modified with small ubiquitin-related modifier (SUMO) proteins was associated with transcriptionally repressive regulatory complexes containing unliganded peroxisome proliferator-activated receptor-delta (PPAR-delta) and co-repressors and thus inhibited Cpt1b, Ucp2 and Ucp3 expression. Upon agonist stimulation of PPAR-delta, KLF5 was deSUMOylated, and became associated with transcriptional activation complexes containing both the liganded PPAR-delta and CREB binding protein (CBP). This activation complex increased the expression of Cpt1b, Ucp2 and Ucp3. Thus, SUMOylation seems to be a molecular switch affecting function of KLF5 and the transcriptional regulatory programs governing lipid metabolism.
Collapse
|
34
|
Kim JE, Kim YW, Lee IK, Kim JY, Kang YJ, Park SY. AMP-activated protein kinase activation by 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) inhibits palmitate-induced endothelial cell apoptosis through reactive oxygen species suppression. J Pharmacol Sci 2008; 106:394-403. [PMID: 18360094 DOI: 10.1254/jphs.fp0071857] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
AMP-activated protein kinase (AMPK) activation has an antiapoptotic effect in endothelial cells, but the mechanisms involved remain unclear. Here, we investigated whether AMPK activation could inhibit palmitate-induced apoptosis through suppression of reactive oxygen species (ROS) production in bovine aortic endothelial cells. Palmitate increases ROS generation and thereby p38 activation, which leads to apoptosis in bovine aortic endothelial cells. The AMPK activator 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) and constitutive active AMPK inhibit palmitate-induced apoptosis through suppression of ROS. The AMPK inhibitor compound C, dominant-negative AMPK, and the uncoupling protein inhibitor guanosine diphosphate block the antiapoptotic and antioxidative effects of AICAR. The increase in uncoupling protein 2 (UCP2) by AICAR is also suppressed by compound C and guanosine diphosphate. AICAR-mediated suppression of palmitate-induced p38 activation is also inhibited by guanosine diphosphate. Over-expression of UCP2 inhibits palmitate-induced apoptosis and ROS generation. These data suggest that the activation of AMPK inhibits palmitate-induced endothelial cell apoptosis through the suppression of ROS generation, and UCP-2 may be one of possible mediators of the antioxidative effect of AMPK.
Collapse
Affiliation(s)
- Ji-Eun Kim
- Department of Physiology, College of Medicine, Yeungnam University, Korea
| | | | | | | | | | | |
Collapse
|
35
|
Abstract
Glucotoxicity, lipotoxicity, and glucolipotoxicity are secondary phenomena that are proposed to play a role in all forms of type 2 diabetes. The underlying concept is that once the primary pathogenesis of diabetes is established, probably involving both genetic and environmental forces, hyperglycemia and very commonly hyperlipidemia ensue and thereafter exert additional damaging or toxic effects on the beta-cell. In addition to their contribution to the deterioration of beta-cell function after the onset of the disease, elevations of plasma fatty acid levels that often accompany insulin resistance may, as glucose levels begin to rise outside of the normal range, also play a pathogenic role in the early stages of the disease. Because hyperglycemia is a prerequisite for lipotoxicity to occur, the term glucolipotoxicity, rather than lipotoxicity, is more appropriate to describe deleterious effects of lipids on beta-cell function. In vitro and in vivo evidence supporting the concept of glucotoxicity is presented first, as well as a description of the underlying mechanisms with an emphasis on the role of oxidative stress. Second, we discuss the functional manifestations of glucolipotoxicity on insulin secretion, insulin gene expression, and beta-cell death, and the role of glucose in the mechanisms of glucolipotoxicity. Finally, we attempt to define the role of these phenomena in the natural history of beta-cell compensation, decompensation, and failure during the course of type 2 diabetes.
Collapse
Affiliation(s)
- Vincent Poitout
- Montreal Diabetes Research Center, CR-CHUM, Technopole Angus, 2901 Rachel Est, Montreal, Quebec, Canada H1W 4A4.
| | | |
Collapse
|
36
|
Liver X receptor alpha is a transcriptional repressor of the uncoupling protein 1 gene and the brown fat phenotype. Mol Cell Biol 2008; 28:2187-200. [PMID: 18195045 DOI: 10.1128/mcb.01479-07] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The adipocyte integrates crucial information about metabolic needs in order to balance energy intake, storage, and expenditure. Whereas white adipose tissue stores energy, brown adipose tissue is a major site of energy dissipation through adaptive thermogenesis mediated by uncoupling protein 1 (UCP1) in mammals. In both white and brown adipose tissue, nuclear receptors and their coregulators, such as peroxisome proliferator-activated receptor gamma (PPARgamma) and PPARgamma coactivator 1alpha (PGC-1alpha), play key roles in regulating their development and metabolic functions. Here we show the unexpected role of liver X receptor alpha (LXRalpha) as a direct transcriptional inhibitor of beta-adrenergic receptor-mediated, cyclic AMP-dependent Ucp1 gene expression through its binding to the critical enhancer region of the Ucp1 promoter. The mechanism of inhibition involves the differential recruitment of the corepressor RIP140 to an LXRalpha binding site that overlaps with the PPARgamma/PGC-1alpha response element, resulting in the dismissal of PPARgamma. The ability of LXRalpha to dampen energy expenditure in this way provides another mechanism for maintaining a balance between energy storage and utilization.
Collapse
|
37
|
Selimovic D, Hassan M, Haikel Y, Hengge UR. Taxol-induced mitochondrial stress in melanoma cells is mediated by activation of c-Jun N-terminal kinase (JNK) and p38 pathways via uncoupling protein 2. Cell Signal 2007; 20:311-22. [PMID: 18068334 DOI: 10.1016/j.cellsig.2007.10.015] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Accepted: 10/07/2007] [Indexed: 02/07/2023]
Abstract
Taxol (paclitaxel) is a new antineoplastic drug that has shown promise in the treatment of different tumor types. However, the molecular mechanisms governing taxol-induced apoptosis are poorly understood. Activation of mitogen-activated protein (MAP) kinases is induced by a wide variety of external stress signals and may lead to apoptosis. Therefore, we challenged the human melanoma cell lines A375 and BLM with taxol and characterized the molecular mechanisms regulating taxol-induced apoptosis. Taxol resulted in the activation of apoptosis signal regulated kinase (ASK)1, c-jun NH(2)-terminal kinase (JNK), p38(MAPK) and extracellular-regulated kinase (ERK) together with the downregulation of uncoupling protein 2 (UCP2). In addition, reactive oxygen species (ROS) were induced and DNA-binding activity of the transcription factors AP-1, ATF-2 and ELK-1 was enhanced. Ultimately, cytochrome c was released, and caspases-9 and -3 as well as PARP were cleaved. Pretreatment of melanoma cells with the JNK inhibitor (SP600125) or the p38 inhibitor (SB203580) blocked taxol-induced UCP2 downregulation, ROS generation and apoptosis, whereas the ERK inhibitor (PD98059) had no such effect. Our data provide evidence that taxol-induced mitochondrial stress occurs through the activation of both JNK and p38 pathways, and suggest a novel role for UCP2 in the modulation of taxol-induced apoptosis of melanoma cells.
Collapse
Affiliation(s)
- Denis Selimovic
- Laboratory for Molecular Tumour Therapy, Department of Dermatology, University Hospital of Duesseldorf, Duesseldorf, Germany
| | | | | | | |
Collapse
|
38
|
Tordjman J, Leroyer S, Chauvet G, Quette J, Chauvet C, Tomkiewicz C, Chapron C, Barouki R, Forest C, Aggerbeck M, Antoine B. Cytosolic aspartate aminotransferase, a new partner in adipocyte glyceroneogenesis and an atypical target of thiazolidinedione. J Biol Chem 2007; 282:23591-602. [PMID: 17545671 DOI: 10.1074/jbc.m611111200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We show that cytosolic aspartate aminotransferase (cAspAT) is involved in adipocyte glyceroneogenesis, a regulated pathway that controls fatty acid homeostasis by promoting glycerol 3-phosphate formation for fatty acid re-esterification during fasting. cAspAT activity, as well as the incorporation of [(14)C]aspartate into the neutral lipid fraction of 3T3-F442A adipocytes was stimulated by the thiazolidinedione (TZD) rosiglitazone. Conversely, the ratio of fatty acid to glycerol released into the medium decreased. Regulation of cAspAT gene expression was specific to differentiated adipocytes and did not require any peroxisome proliferator-activated receptor gamma (PPARgamma)/retinoid X receptor-alpha direct binding. Nevertheless, PPARgamma is indirectly necessary for both cAspAT basal expression and TZD responsiveness because they are, respectively, diminished and abolished by ectopic overexpression of a dominant negative PPARgamma. The cAspAT TZD-responsive site was restricted to a single AGGACA hexanucleotide located at -381 to -376 bp whose mutation impaired the specific RORalpha binding. RORalpha ectopic expression activated the cAspAT gene transcription in absence of rosiglitazone, and its protein amount in nuclear extracts is 1.8-fold increased by rosiglitazone treatment of adipocytes. Finally, the amounts of RORalpha and cAspAT mRNAs were similarly increased by TZD treatment of human adipose tissue explants, confirming coordinated regulation. Our data identify cAspAT as a new member of glyceroneogenesis, transcriptionally regulated by TZD via the control of RORalpha expression by PPARgamma in adipocytes.
Collapse
Affiliation(s)
- Joan Tordjman
- Inserm U530, Université Paris Descartes, F-75006, Paris, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Zhang X, Li L, Prabhakaran K, Zhang L, Leavesley H, Borowitz J, Isom G. Uncoupling protein-2 up-regulation and enhanced cyanide toxicity are mediated by PPARalpha activation and oxidative stress. Toxicol Appl Pharmacol 2007; 223:10-9. [PMID: 17573087 PMCID: PMC1994772 DOI: 10.1016/j.taap.2007.05.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Revised: 05/07/2007] [Accepted: 05/09/2007] [Indexed: 12/17/2022]
Abstract
Uncoupling protein 2 (UCP-2) is an inner mitochondrial membrane proton carrier that modulates mitochondrial membrane potential (DeltaPsi(m)) and uncouples oxidative phosphorylation. We have shown that up-regulation of UCP-2 by Wy14,643, a selective peroxisome proliferator-activated receptor-alpha (PPARalpha) agonist, enhances cyanide cytotoxicity. The pathway by which Wy14,643 up-regulates UCP-2 was determined in a dopaminergic cell line (N27 cells). Since dopaminergic mesencephalic cells are a primary brain target of cyanide, the N27 immortalized mesencephalic cell was used in this study. Wy14,643 produced a concentration- and time-dependent up-regulation of UCP-2 that was linked to enhanced cyanide-induced cell death. MK886 (PPARalpha antagonist) or PPARalpha knock-down by RNA interference (RNAi) inhibited PPARalpha activity as shown by the peroxisome proliferator response element-luciferase reporter assay, but only partially decreased up-regulation of UCP-2. The role of oxidative stress as an alternative pathway to UCP-2 up-regulation was determined. Wy14,643 induced a rapid surge of ROS generation and loading cells with glutathione ethyl ester (GSH-EE) or pre-treatment with vitamin E attenuated up-regulation of UCP-2. On the other hand, RNAi knockdown of PPARalpha did not alter ROS generation, suggesting a PPARalpha-independent component to the response. Co-treatment with PPARalpha-RNAi and GSH-EE blocked both the up-regulation of UCP-2 by Wy14,643 and the cyanide-induced cell death. It was concluded that a PPARalpha-mediated pathway and an oxidative stress pathway independent of PPARalpha mediate the up-regulation of UCP-2 and subsequent increased vulnerability to cyanide-induced cytotoxicity.
Collapse
Affiliation(s)
| | | | | | | | | | | | - G.E. Isom
- * Corresponding author. Fax: +1 765 404 1414. E-mail address: (G.E. Isom)
| |
Collapse
|
40
|
FUKUDA H, HIRAKAWA T, IRITANI N. Nutritional and Hormonal Regulation of Uncoupling Protein Gene Expression in Rat Adipocytes. J Nutr Sci Vitaminol (Tokyo) 2007; 53:426-31. [DOI: 10.3177/jnsv.53.426] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Hitomi FUKUDA
- Faculty of Human and Cultural Studies, Tezukayama Gakuin University
| | - Tomoe HIRAKAWA
- Faculty of Human and Cultural Studies, Tezukayama Gakuin University
| | - Nobuko IRITANI
- Faculty of Human and Cultural Studies, Tezukayama Gakuin University
| |
Collapse
|
41
|
Ota M, Nakashima A, Kaneko YS, Mori K, Takami G, Ota A. Risperidone reduces mRNA expression levels of Sulfonylurea Receptor 1 and TASK1 in PC12 cells. Neurosci Lett 2006; 412:254-8. [PMID: 17174476 DOI: 10.1016/j.neulet.2006.11.018] [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: 08/19/2006] [Revised: 11/04/2006] [Accepted: 11/07/2006] [Indexed: 11/18/2022]
Abstract
Electrophysiological and immunohistochemical studies have demonstrated that glucose-sensing neurons in the hypothalamus contain both ATP-sensitive K(+) (K(ATP)) and tandem-pore K(+) (TASK1 and TASK3) channels and that glucose-induced depolarization or hyperpolarization of these neurons function as an important link between glucose-excited or glucose-inhibited neurons and feeding behavior. Medication with atypical antipsychotics increases the appetite of schizophrenic patients and thus causes increases in body weight. Therefore, the present study investigates mRNA expression levels of the genes encoding the components of these K(+) channel subsets in PC12 cells cultured with risperidone (an atypical antipsychotic) and in the hypothalami of rats subcutaneously injected for 21 consecutive days with 0.1 or 0.01 mg/kg/day of risperidone. The mRNA expression levels of various genes were not obviously altered in rat hypothalami. However, the mRNA expression levels for sulfonylurea receptor 1, a component affording nucleotide-binding folds to K(ATP) channels, and TASK1 were down-regulated in PC12 cells cultured with 50 microM risperidone for 24h, but the amount of intracellular ATP in these cells was not affected by the drug. Collectively, these results indicate that the amplitude of the current through these K(+) channels in PC12 cells might be modulated as a pharmacological effect of risperidone.
Collapse
Affiliation(s)
- Miyuki Ota
- Department of Neuropsychiatry, Tosei General Hospital, Seto 489-8642, Japan
| | | | | | | | | | | |
Collapse
|
42
|
Eldor R, Raz I. Lipotoxicity versus adipotoxicity—The deleterious effects of adipose tissue on beta cells in the pathogenesis of type 2 diabetes. Diabetes Res Clin Pract 2006. [DOI: 10.1016/j.diabres.2006.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
43
|
Joosen AMCP, Bakker AHF, Zorenc AHG, Kersten S, Schrauwen P, Westerterp KR. PPARgamma activity in subcutaneous abdominal fat tissue and fat mass gain during short-term overfeeding. Int J Obes (Lond) 2006; 30:302-7. [PMID: 16247507 DOI: 10.1038/sj.ijo.0803146] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE As the peroxisome proliferator-activated receptor gamma (PPARgamma) plays a central role in fat mass regulation, we investigated whether initial subcutaneous PPARgamma activity is related to fat mass generation during overfeeding. SUBJECTS Fourteen healthy female subjects (age 25 +/- 4 years, BMI 22.1 +/- 2.3 kg/m2). DESIGN AND MEASUREMENTS Subjects were overfed with a diet supplying 50% more energy than baseline energy requirements for 14 days. Fasting blood samples were analyzed for leptin, insulin and glucose. Fasting subcutaneous abdominal fat biopsies were obtained for analysis of PPARgamma1, PPARgamma2, aP2 and UCP2 mRNAs. RESULTS Initial PPARgamma1 and 2, aP2 and UCP2 mRNAs were not related to fat gain (P > 0.12). However, PPARgamma1, PPARgamma2 and aP2 mRNA changes were positively related to changes in plasma leptin (P < 0.05) and, except aP2 (P = 0.06), to fat gain (P < 0.05). PPARgamma and aP2 mRNA changes were positively related (P<0.01), indicating that PPARgamma mRNA levels reflected PPARgamma activity. CONCLUSION These data suggest that the ability to increase PPARgamma activity might be involved in the susceptibility to gain weight during a positive energy balance.
Collapse
Affiliation(s)
- A M C P Joosen
- Department of Human Biology, Maastricht University, Maastricht, The Netherlands.
| | | | | | | | | | | |
Collapse
|
44
|
Vatamaniuk MZ, Gupta RK, Lantz KA, Doliba NM, Matschinsky FM, Kaestner KH. Foxa1-deficient mice exhibit impaired insulin secretion due to uncoupled oxidative phosphorylation. Diabetes 2006; 55:2730-6. [PMID: 17003337 DOI: 10.2337/db05-0470] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Foxa1 (formerly hepatic nuclear factor 3alpha) belongs to the family of Foxa genes that are expressed in early development and takes part in the differentiation of endoderm-derived organs and the regulation of glucose homeostasis. Foxa1-/- pups are growth retarded and hypoglycemic but glucose intolerant in response to an intraperitoneal glucose challenge. However, the mechanism of glucose intolerance in this model has not been investigated. Here, we show that Foxa1-/- islets exhibit decreased glucose-stimulated insulin release in islet perifusion experiments and have significantly reduced pancreatic insulin and glucagon content. Moreover, Foxa1-/- beta-cells exhibit attenuated calcium influx in response to glucose and glyburide, suggesting an insulin secretion defect either at the level or upstream of the ATP-sensitive K+ channel. Intracellular ATP levels after incubation with 10 mmol/l glucose were about 2.5 times lower in Foxa1-/- islets compared with controls. This diminished ATP synthesis could be explained by increased expression of the mitochondrial uncoupling protein uncoupling protein 2 (UCP2) in Foxa1-deficient islets, resulting in partially uncoupled mitochondria. Chromatin immunoprecipitation assays indicate that UCP2 is a direct transcriptional target of Foxa1 in vivo. Thus, we have identified a novel function for Foxa1 in the regulation of oxidative phosphorylation in pancreatic beta-cells.
Collapse
Affiliation(s)
- Marko Z Vatamaniuk
- Department of Genetics and Institute of Diabetes, Obesity and Metabolism, University of Pennsylvania School of Medicine, 415 Curie Blvd., Philadelphia, PA 19104-6145, USA
| | | | | | | | | | | |
Collapse
|
45
|
Thermal sensitivity of uncoupling protein expression in polar and temperate fish. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2006; 1:365-74. [PMID: 20483268 DOI: 10.1016/j.cbd.2006.08.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Revised: 08/06/2006] [Accepted: 08/07/2006] [Indexed: 11/21/2022]
Abstract
Uncoupling proteins (UCP), capable of increasing proton leakage across the inner mitochondrial membrane, may play a role in the temperature-dependent setting of energy turnover in animals (and their mitochondria). Therefore, the genes and expression of fish UCP were investigated in the Antarctic eelpout Pachycara brachycephalum and a temperate confamilial species, the common eelpout Zoarces viviparus. UCP full-length cDNA was amplified from liver and muscle using RT-PCR and rapid amplification of cDNA ends (RACE). The fish UCP mRNA consists of 1906 bp in P. brachycephalum and of 1876 bp in Z. viviparus. Both zoarcid sequences contain open reading frames of 939 bp, encoding 313 amino acids, with 98% and 99% identity, respectively. Protein sequences of zoarcid UCP are closest related to fish and mammalian UCP2. For analysis of temperature-dependent expression common eelpouts were cold-acclimated from 10 degrees C to 2 degrees C and Antarctic eelpouts were warm-acclimated from 0 degrees C to 5 degrees C. Identical cDNA probes for both species were developed to investigate fish UCP mRNA expression, and protein expression levels were detected by Western Blot in the enriched membrane fraction. During cold-acclimation in Z. viviparus, mRNA levels increased by a factor up to 2.0, protein levels increased up to 1.5, in line with mitochondrial proliferation during cold-acclimation. Despite decreased mitochondrial protein content, in Antarctic eelpout UCP levels rose upon warm acclimation by a factor up to 2.0 (mRNA) and 1.6 (protein), respectively. Besides the ongoing discussion of UCP function in vertebrates, the data are indicative of a significant role of fish UCP in thermal adaptation of fish mitochondria.
Collapse
|
46
|
Borniquel S, Valle I, Cadenas S, Lamas S, Monsalve M. Nitric oxide regulates mitochondrial oxidative stress protection via the transcriptional coactivator PGC-1alpha. FASEB J 2006; 20:1889-91. [PMID: 16891621 DOI: 10.1096/fj.05-5189fje] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nitric oxide (NO) has both prooxidant and antioxidant activities in the endothelium; however, the molecular mechanisms involved are still a matter of controversy. PGC-1alpha [peroxisome proliferators-activated receptor (PPAR) gamma coactivator 1-alpha] induces the expression of several members of the mitochondrial reactive oxygen species (ROS) detoxification system. Here, we show that NO regulates this system through the modulation of PGC-1alpha expression. Short-term (<12 h) treatment of endothelial cells with NO donors down-regulates PGC-1alpha expression, whereas long-term (>24 h) treatment up-regulates it. Treatment with the NOS inhibitor l-NAME has the opposite effect. Down-regulation of PGC-1alpha by NO is mediated by protein kinase G (PKG). It is blocked by the soluble guanylate cyclase (sGC) inhibitor ODQ and the PKG inhibitor KT5823, and mimicked by the cGMP analog 8-Br-cGMP. Changes in PGC-1alpha expression are in all cases paralleled by corresponding variations in the mitochondrial ROS detoxification system. Cells that transiently overexpress PGC-1alpha from the cytomeglovirus (CMV) promoter respond poorly to NO donors. Analysis of tissues from eNOS(-/-) mice showed reduced levels of PGC-1alpha and the mitochondrial ROS detoxification system. These data suggest that NO can regulate the mitochondrial ROS detoxification system both positively and negatively through PGC-1alpha.
Collapse
Affiliation(s)
- Sara Borniquel
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernandez Almagro 3, Madrid 28029, Spain
| | | | | | | | | |
Collapse
|
47
|
Abstract
The uncoupling proteins (UCPs) are attracting an increased interest as potential therapeutic targets in a number of important diseases. UCP2 is expressed in several tissues, but its physiological functions as well as potential therapeutic applications are still unclear. Unlike UCP1, UCP2 does not seem to be important to thermogenesis or weight control, but appears to have an important role in the regulation of production of reactive oxygen species, inhibition of inflammation, and inhibition of cell death. These are central features in, for example, neurodegenerative and cardiovascular disease, and experimental evidence suggests that an increased expression and activity of UCP2 in models of these diseases has a beneficial effect on disease progression, implicating a potential therapeutic role for UCP2. UCP2 has an important role in the pathogenesis of type 2 diabetes by inhibiting insulin secretion in islet beta cells. At the same time, type 2 diabetes is associated with increased risk of cardiovascular disease and atherosclerosis where an increased expression of UCP2 appears to be beneficial. This illustrates that therapeutic applications involving UCP2 likely will have to regulate expression and activity in a tissue-specific manner.
Collapse
Affiliation(s)
- Gustav Mattiasson
- Laboratory for Experimental Brain Research, Wallenberg Neuroscience Center, Lund, Sweden.
| | | |
Collapse
|
48
|
Bordone L, Motta MC, Picard F, Robinson A, Jhala US, Apfeld J, McDonagh T, Lemieux M, McBurney M, Szilvasi A, Easlon EJ, Lin SJ, Guarente L. Sirt1 regulates insulin secretion by repressing UCP2 in pancreatic beta cells. PLoS Biol 2005; 4:e31. [PMID: 16366736 PMCID: PMC1318478 DOI: 10.1371/journal.pbio.0040031] [Citation(s) in RCA: 522] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Accepted: 11/22/2005] [Indexed: 02/06/2023] Open
Abstract
Sir2 and insulin/IGF-1 are the major pathways that impinge upon aging in lower organisms. In Caenorhabditis elegans a possible genetic link between Sir2 and the insulin/IGF-1 pathway has been reported. Here we investigate such a link in mammals. We show that Sirt1 positively regulates insulin secretion in pancreatic β cells. Sirt1 represses the uncoupling protein (UCP) gene UCP2 by binding directly to the UCP2 promoter. In β cell lines in which Sirt1 is reduced by SiRNA, UCP2 levels are elevated and insulin secretion is blunted. The up-regulation of UCP2 is associated with a failure of cells to increase ATP levels after glucose stimulation. Knockdown of UCP2 restores the ability to secrete insulin in cells with reduced Sirt1, showing that UCP2 causes the defect in glucose-stimulated insulin secretion. Food deprivation induces UCP2 in mouse pancreas, which may occur via a reduction in NAD (a derivative of niacin) levels in the pancreas and down-regulation of Sirt1. Sirt1 knockout mice display constitutively high UCP2 expression. Our findings show that Sirt1 regulates UCP2 in β cells to affect insulin secretion. Sirt1 is shown to regulate the expression of the metabolic decoupling gene UCP2 in pancreatic β cells, highlighting a possible role for Sirt1 in coordinating insulin release in response to changing dietary conditions.
Collapse
Affiliation(s)
- Laura Bordone
- 1Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail: (LB); E-mail: (LG)
| | - Maria Carla Motta
- 1Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Frederic Picard
- 2Laval Hospital Research Center, Québec City, Québec, Canada
| | - Ashley Robinson
- 1Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Ulupi S Jhala
- 3The Whittier Institute for Diabetes, University of California San Diego, La Jolla, California, United States of America
| | - Javier Apfeld
- 4Elixir Pharmaceuticals, Cambridge, Massachusetts, United States of America
| | - Thomas McDonagh
- 4Elixir Pharmaceuticals, Cambridge, Massachusetts, United States of America
| | - Madeleine Lemieux
- 5Department of Medicine and Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, and the Ottawa Regional Cancer Centre, Ottawa, Ontario, Canada
| | - Michael McBurney
- 5Department of Medicine and Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, and the Ottawa Regional Cancer Centre, Ottawa, Ontario, Canada
| | - Akos Szilvasi
- 6Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
| | - Erin J Easlon
- 7Center for Genetics and Development, and Section of Microbiology, University of California Davis, Davis, California, United States of America
| | - Su-Ju Lin
- 7Center for Genetics and Development, and Section of Microbiology, University of California Davis, Davis, California, United States of America
| | - Leonard Guarente
- 1Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail: (LB); E-mail: (LG)
| |
Collapse
|
49
|
Cao W, Collins QF, Becker TC, Robidoux J, Lupo EG, Xiong Y, Daniel KW, Floering L, Collins S. p38 Mitogen-activated protein kinase plays a stimulatory role in hepatic gluconeogenesis. J Biol Chem 2005; 280:42731-7. [PMID: 16272151 DOI: 10.1074/jbc.m506223200] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Hepatic gluconeogenesis is essential for maintaining blood glucose levels during fasting and is the major contributor to postprandial and fasting hyperglycemia in diabetes. Gluconeogenesis is a classic cAMP/protein kinase A-dependent process initiated by glucagon, which is elevated in the blood during fasting and in diabetes. In this study, we have shown that p38 mitogen-activated protein kinase (p38) was activated in liver by fasting and in primary hepatocytes by glucagon or forskolin. Fasting plasma glucose levels were reduced upon blockade of p38 with either a chemical inhibitor or small interference RNA in mice. In examining the mechanism, inhibition of p38 suppressed gluconeogenesis in liver, along with expression of key gluconeogenic genes, including phosphoenolpyruvate carboxykinase and glucose-6-phosphatase. Peroxisome proliferator-activated receptor gamma coactivator 1alpha and cAMP-response element-binding protein have been shown to be important mediators of hepatic gluconeogenesis. We have shown that inhibition of p38 prevented transcription of the PPARgamma coactivator 1alpha gene as well as phosphorylation of cAMP-response element-binding protein. Together, our results from in vitro and in vivo studies define a model in which cAMP-dependent activation of genes involved in gluconeogenesis is dependent upon the p38 pathway, thus adding a new player to our evolving understanding of this physiology.
Collapse
Affiliation(s)
- Wenhong Cao
- Endocrine Biology Program, CIIT Centers for Health Research, Research Triangle Park, North Carolina 27709, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Bispham J, Gardner DS, Gnanalingham MG, Stephenson T, Symonds ME, Budge H. Maternal nutritional programming of fetal adipose tissue development: differential effects on messenger ribonucleic acid abundance for uncoupling proteins and peroxisome proliferator-activated and prolactin receptors. Endocrinology 2005; 146:3943-9. [PMID: 15961559 DOI: 10.1210/en.2005-0246] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Maternal nutrient restriction at specific stages of gestation has differential effects on fetal development such that the offspring are programmed to be at increased risk of a range of adult diseases, including obesity. We investigated the effect of maternal nutritional manipulation through gestation on fetal adipose tissue deposition in conjunction with mRNA abundance for uncoupling protein (UCP)1 and 2, peroxisome proliferator-activated receptors (PPAR)alpha and gamma, together with long and short forms of the prolactin receptor (PRLR). Singleton-bearing ewes were either nutrient restricted (3.2-3.8 MJ day(-1) metabolizable energy) or fed to appetite (8.7-9.9 MJ day(-1)) over the period of maximal placental growth, i.e. between 28 and 80 d gestation. After 80 d gestation, ewes were either fed to calculated requirements, (6.7-7.5 MJ day(-1)), or to appetite (8.0-10.9 MJ day(-1)). At term, offspring of nutrient-restricted ewes possessed more adipose tissue, an adaptation that was greatest in those born to mothers that fed to requirements in late gestation. This was accompanied by an increased mRNA abundance for UCP2 and PPARalpha, an adaptation not seen in mothers re-fed to appetite. Maternal nutrition had no effect on mRNA abundance for UCP1, PPARgamma, or PRLR. Irrespective of maternal nutrition, mRNA abundance for UCP1 was positively correlated with PPARgamma and the long and short forms of PRLR, indicating that these factors may act together to ensure that UCP1 abundance is maximized in the newborn. In conclusion, we have shown, for the first time, differential effects of maternal nutrition on key regulatory components of fetal fat metabolism.
Collapse
Affiliation(s)
- J Bispham
- Centre for Reproduction and Early Life, Institute of Clinical Research, University of Nottingham, United Kingdom
| | | | | | | | | | | |
Collapse
|