1
|
Ketema EB, Lopaschuk GD. Post-translational Acetylation Control of Cardiac Energy Metabolism. Front Cardiovasc Med 2021; 8:723996. [PMID: 34409084 PMCID: PMC8365027 DOI: 10.3389/fcvm.2021.723996] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 06/30/2021] [Indexed: 12/17/2022] Open
Abstract
Perturbations in myocardial energy substrate metabolism are key contributors to the pathogenesis of heart diseases. However, the underlying causes of these metabolic alterations remain poorly understood. Recently, post-translational acetylation-mediated modification of metabolic enzymes has emerged as one of the important regulatory mechanisms for these metabolic changes. Nevertheless, despite the growing reports of a large number of acetylated cardiac mitochondrial proteins involved in energy metabolism, the functional consequences of these acetylation changes and how they correlate to metabolic alterations and myocardial dysfunction are not clearly defined. This review summarizes the evidence for a role of cardiac mitochondrial protein acetylation in altering the function of major metabolic enzymes and myocardial energy metabolism in various cardiovascular disease conditions.
Collapse
Affiliation(s)
- Ezra B Ketema
- Department of Pediatrics, Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada
| | - Gary D Lopaschuk
- Department of Pediatrics, Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
2
|
Rubio B, Mora C, Pintado C, Mazuecos L, Fernández A, López V, Andrés A, Gallardo N. The nutrient sensing pathways FoxO1/3 and mTOR in the heart are coordinately regulated by central leptin through PPARβ/δ. Implications in cardiac remodeling. Metabolism 2021; 115:154453. [PMID: 33249043 DOI: 10.1016/j.metabol.2020.154453] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/11/2020] [Accepted: 11/23/2020] [Indexed: 10/22/2022]
Abstract
BACKGROUND Cardiovascular disease in obese individuals with type 2 diabetes is often associated with hyperleptinemia and leptin resistance, while other studies support that leptin has cardioprotective effects. Besides, the role of leptin in regulating cardiac atrophy or hypertrophy remains to be clearly defined. In fact, in rats with normal leptin sensitivity, the molecular underpinnings of the effects of central leptin regulating cardiac structural pathways remain poorly understood. OBJECTIVE Hence, we assessed the effects of intracerebroventricular (icv) leptin infusion on cardiac remodeling analyzing FOXO1/3 and mTORC1 pathways, focusing special attention to PPARβ/δ as mediator of central leptin's effects on cardiac metabolism. METHODS Male 3-months-old Wistar rats, infused with icv leptin (0.2 μg/day) for 7 days, were daily co-treated intraperitoneally with the specific PPARβ/δ antagonist GSK0660, at 1 mg/kg per day along leptin treatment. RESULTS Central leptin regulated dynamically, in an opposite manner, the network between FOXOs and mTORC1 and induced an atrophy-related gene program in cardiac tissue. Leptin activated the anti-hypertrophic kinase GSK3β and increased the protein levels of muscle-specific ubiquitin ligases, muscle RING finger 1 (MuRF1) and muscle atrophy F-box (MAFbx)/Atrogin-1 involved in limiting cardiac hypertrophy. FOXO1 activity and the expression of their target genes, Sod2 and Lpl, were also increased in the heart upon central leptin infusion. Besides, Beclin-1 and LC3B-II, gene products of the autophagic pathway response, were upregulated, while the content and expression levels of phenotypic markers of cardiac hypertrophy as ANP and β-myosin heavy chain, gene product of Myh7 were significantly decreased. On the other hand, mTORC1 activity and OXPHOS protein levels were decreased suggesting a key role of central leptin preventing cardiac oxidative stress. In fact, the content of carbonylated proteins, TBARS and ROS/RSN were not increased in cardiac tissue in response to central leptin infusion. Finally, the pharmacological inhibition of PPARβ/δ, via in vivo administration of the selective antagonist GSK0660, blunted the induction of FOXO1/3, Atrogin-1, MuRF1 and GSK3β in the heart mediated by icv leptin infusion. CONCLUSIONS Our results demonstrate that, in lean rats with normal leptin sensitivity, central leptin regulates nutrient sensing pathways in heart contributing to balance cardiac remodeling through the anti- and pro-hypertrophic programs, and in this process is involved PPARβ/δ.
Collapse
Affiliation(s)
- Blanca Rubio
- Universidad de Castilla-La Mancha, Regional Centre for Biomedical Research, Spain; Universidad de Castilla-La Mancha, Biochemistry Section, Faculty of Science and Chemical Technologies, Avda Camilo José Cela 10, 13071 Ciudad Real, Spain
| | - Cristina Mora
- Universidad de Castilla-La Mancha, Regional Centre for Biomedical Research, Spain; Universidad de Castilla-La Mancha, Biochemistry Section, Faculty of Science and Chemical Technologies, Avda Camilo José Cela 10, 13071 Ciudad Real, Spain
| | - Cristina Pintado
- Universidad de Castilla-La Mancha, Regional Centre for Biomedical Research, Spain; Universidad de Castilla-La Mancha, Biochemistry Section, Faculty of Environmental Sciences and Biochemistry, Avda. Carlos III s/n, 45071 Toledo, Spain
| | - Lorena Mazuecos
- Universidad de Castilla-La Mancha, Regional Centre for Biomedical Research, Spain; Universidad de Castilla-La Mancha, Biochemistry Section, Faculty of Science and Chemical Technologies, Avda Camilo José Cela 10, 13071 Ciudad Real, Spain
| | - Alejandro Fernández
- Universidad de Castilla-La Mancha, Regional Centre for Biomedical Research, Spain; Universidad de Castilla-La Mancha, Biochemistry Section, Faculty of Science and Chemical Technologies, Avda Camilo José Cela 10, 13071 Ciudad Real, Spain
| | - Virginia López
- Universidad de Castilla-La Mancha, Regional Centre for Biomedical Research, Spain; Universidad de Castilla-La Mancha, Biochemistry Section, Faculty of Science and Chemical Technologies, Avda Camilo José Cela 10, 13071 Ciudad Real, Spain
| | - Antonio Andrés
- Universidad de Castilla-La Mancha, Regional Centre for Biomedical Research, Spain; Universidad de Castilla-La Mancha, Biochemistry Section, Faculty of Science and Chemical Technologies, Avda Camilo José Cela 10, 13071 Ciudad Real, Spain.
| | - Nilda Gallardo
- Universidad de Castilla-La Mancha, Regional Centre for Biomedical Research, Spain; Universidad de Castilla-La Mancha, Biochemistry Section, Faculty of Science and Chemical Technologies, Avda Camilo José Cela 10, 13071 Ciudad Real, Spain.
| |
Collapse
|
3
|
Pereira S, Cline DL, Glavas MM, Covey SD, Kieffer TJ. Tissue-Specific Effects of Leptin on Glucose and Lipid Metabolism. Endocr Rev 2021; 42:1-28. [PMID: 33150398 PMCID: PMC7846142 DOI: 10.1210/endrev/bnaa027] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Indexed: 12/18/2022]
Abstract
The discovery of leptin was intrinsically associated with its ability to regulate body weight. However, the effects of leptin are more far-reaching and include profound glucose-lowering and anti-lipogenic effects, independent of leptin's regulation of body weight. Regulation of glucose metabolism by leptin is mediated both centrally and via peripheral tissues and is influenced by the activation status of insulin signaling pathways. Ectopic fat accumulation is diminished by both central and peripheral leptin, an effect that is beneficial in obesity-associated disorders. The magnitude of leptin action depends upon the tissue, sex, and context being examined. Peripheral tissues that are of particular relevance include the endocrine pancreas, liver, skeletal muscle, adipose tissues, immune cells, and the cardiovascular system. As a result of its potent metabolic activity, leptin is used to control hyperglycemia in patients with lipodystrophy and is being explored as an adjunct to insulin in patients with type 1 diabetes. To fully understand the role of leptin in physiology and to maximize its therapeutic potential, the mechanisms of leptin action in these tissues needs to be further explored.
Collapse
Affiliation(s)
- Sandra Pereira
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Daemon L Cline
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Maria M Glavas
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Scott D Covey
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Timothy J Kieffer
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.,Department of Surgery, University of British Columbia, Vancouver, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, Canada
| |
Collapse
|
4
|
Gava FN, da Silva AA, Dai X, Harmancey R, Ashraf S, Omoto ACM, Salgado MC, Moak SP, Li X, Hall JE, do Carmo JM. Restoration of Cardiac Function After Myocardial Infarction by Long-Term Activation of the CNS Leptin-Melanocortin System. JACC Basic Transl Sci 2021; 6:55-70. [PMID: 33532666 PMCID: PMC7838051 DOI: 10.1016/j.jacbts.2020.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 11/12/2020] [Accepted: 11/12/2020] [Indexed: 12/17/2022]
Abstract
Leptin protects against progression to heart failure after myocardial infarction. This beneficial effect requires activation of the brain melanocortin system. Stimulation of brain MC4R recapitulates the cardiac protective effects of leptin. Leptin-MC4R activation improves cardiac substrate oxidation and mitochondrial function. It also improves Ca2+ coupling and contractile function in viable cardiomyocytes after MI.
Heart failure has a high mortality rate, and current therapies offer limited benefits. The authors demonstrate that activation of the central nervous system leptin-melanocortin pathway confers remarkable protection against progressive heart failure following severe myocardial infarction. The beneficial cardiac-protective actions of leptin require activation of brain melanocortin-4 receptors and elicit improvements in cardiac substrate oxidation, cardiomyocyte contractility, Ca2+ coupling, and mitochondrial efficiency. These findings highlight a potentially novel therapeutic approach for myocardial infarction and heart failure.
Collapse
Key Words
- AMPK, adenosine monophosphate–activated protein kinase
- BP, blood pressure
- CNS, central nervous system
- HF, heart failure
- HR, heart rate
- ICV, intracerebroventricular
- LV, left ventricular
- MC4R
- MC4R, melanocortin-4 receptor
- MI, myocardial infarction
- MTII, melanotan II
- appetite
- blood pressure
- cardiac metabolism
- heart failure
- mTOR, mechanistic target of rapamycin
Collapse
Affiliation(s)
- Fabio N Gava
- Department of Physiology and Biophysics and Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA.,Department of Veterinary Clinics, Londrina State University, Parana, Brazil
| | - Alexandre A da Silva
- Department of Physiology and Biophysics and Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Xuemei Dai
- Department of Physiology and Biophysics and Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Romain Harmancey
- Department of Physiology and Biophysics and Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Sadia Ashraf
- Department of Physiology and Biophysics and Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Ana C M Omoto
- Department of Physiology and Biophysics and Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA.,Department of Physiology, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Mateus C Salgado
- Department of Physiology and Biophysics and Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA.,Centro Universitário Barão de Mauá, Ribeirão Preto, São Paulo, Brazil
| | - Sydney P Moak
- Department of Physiology and Biophysics and Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Xuan Li
- Department of Physiology and Biophysics and Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - John E Hall
- Department of Physiology and Biophysics and Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Jussara M do Carmo
- Department of Physiology and Biophysics and Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA
| |
Collapse
|
5
|
Mora C, Pintado C, Rubio B, Mazuecos L, López V, Fernández A, Salamanca A, Bárcena B, Fernández-Agulló T, Arribas C, Gallardo N, Andrés A. Central leptin regulates heart lipid content by selectively increasing PPAR β/δ expression. J Endocrinol 2018; 236:43-56. [PMID: 29109080 DOI: 10.1530/joe-17-0554] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 11/06/2017] [Indexed: 01/03/2023]
Abstract
The role of central leptin in regulating the heart from lipid accumulation in lean leptin-sensitive animals has not been fully elucidated. Herein, we investigated the effects of central leptin infusion on the expression of genes involved in cardiac metabolism and its role in the control of myocardial triacylglyceride (TAG) accumulation in adult Wistar rats. Intracerebroventricular (icv) leptin infusion (0.2 µg/day) for 7 days markedly decreased TAG levels in cardiac tissue. Remarkably, the cardiac anti-steatotic effects of central leptin were associated with the selective upregulation of gene and protein expression of peroxisome proliferator-activated receptor β/δ (PPARβ/δ, encoded by Pparb/d) and their target genes, adipose triglyceride lipase (encoded by Pnpla2, herefater referred to as Atgl), hormone sensitive lipase (encoded by Lipe, herefater referred to as Hsl), pyruvate dehydrogenase kinase 4 (Pdk4) and acyl CoA oxidase 1 (Acox1), involved in myocardial intracellular lipolysis and mitochondrial/peroxisomal fatty acid utilization. Besides, central leptin decreased the expression of stearoyl-CoA deaturase 1 (Scd1) and diacylglycerol acyltransferase 1 (Dgat1) involved in TAG synthesis and increased the CPT-1 independent palmitate oxidation, as an index of peroxisomal β-oxidation. Finally, the pharmacological inhibition of PPARβ/δ decreased the effects on gene expression and cardiac TAG content induced by leptin. These results indicate that leptin, acting at central level, regulates selectively the cardiac expression of PPARβ/δ, contributing in this way to regulate the cardiac TAG accumulation in rats, independently of its effects on body weight.
Collapse
Affiliation(s)
- Cristina Mora
- BiochemistryFaculty of Science and Technological Chemistry, and Regional Centre for Biomedical Research (CRIB), University of Castilla-La Mancha (UCLM), Ciudad Real, Spain
| | - Cristina Pintado
- BiochemistryFaculty of Environmental Sciences and and CRIB, UCLM, Toledo, Spain
| | - Blanca Rubio
- BiochemistryFaculty of Science and Technological Chemistry, and Regional Centre for Biomedical Research (CRIB), University of Castilla-La Mancha (UCLM), Ciudad Real, Spain
| | - Lorena Mazuecos
- BiochemistryFaculty of Science and Technological Chemistry, and Regional Centre for Biomedical Research (CRIB), University of Castilla-La Mancha (UCLM), Ciudad Real, Spain
| | - Virginia López
- BiochemistryFaculty of Science and Technological Chemistry, and Regional Centre for Biomedical Research (CRIB), University of Castilla-La Mancha (UCLM), Ciudad Real, Spain
| | - Alejandro Fernández
- BiochemistryFaculty of Science and Technological Chemistry, and Regional Centre for Biomedical Research (CRIB), University of Castilla-La Mancha (UCLM), Ciudad Real, Spain
| | - Aurora Salamanca
- BiochemistryFaculty of Science and Technological Chemistry, and Regional Centre for Biomedical Research (CRIB), University of Castilla-La Mancha (UCLM), Ciudad Real, Spain
| | - Brenda Bárcena
- BiochemistryFaculty of Science and Technological Chemistry, and Regional Centre for Biomedical Research (CRIB), University of Castilla-La Mancha (UCLM), Ciudad Real, Spain
| | | | - Carmen Arribas
- BiochemistryFaculty of Environmental Sciences and and CRIB, UCLM, Toledo, Spain
| | - Nilda Gallardo
- BiochemistryFaculty of Science and Technological Chemistry, and Regional Centre for Biomedical Research (CRIB), University of Castilla-La Mancha (UCLM), Ciudad Real, Spain
| | - Antonio Andrés
- BiochemistryFaculty of Science and Technological Chemistry, and Regional Centre for Biomedical Research (CRIB), University of Castilla-La Mancha (UCLM), Ciudad Real, Spain
| |
Collapse
|
6
|
Hall ME, Harmancey R, Stec DE. Lean heart: Role of leptin in cardiac hypertrophy and metabolism. World J Cardiol 2015; 7:511-524. [PMID: 26413228 PMCID: PMC4577678 DOI: 10.4330/wjc.v7.i9.511] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/16/2015] [Accepted: 07/23/2015] [Indexed: 02/06/2023] Open
Abstract
Leptin is an adipokine that has been linked with the cardiovascular complications resulting from obesity such as hypertension and heart disease. Obese patients have high levels of circulating leptin due to increased fat mass. Clinical and population studies have correlated high levels of circulating leptin with the development of cardiac hypertrophy in obesity. Leptin has also been demonstrated to increase the growth of cultured cardiomyocytes. However, several animal studies of obese leptin deficient mice have not supported a role for leptin in promoting cardiac hypertrophy so the role of leptin in this pathological process remains unclear. Leptin is also an important hormone in the regulation of cardiac metabolism where it supports oxidation of glucose and fatty acids. In addition, leptin plays a critical role in protecting the heart from excess lipid accumulation and the formation of toxic lipids in obesity a condition known as cardiac lipotoxicity. This paper focuses on the data supporting and refuting leptin’s role in promoting cardiac hypertrophy as well as its important role in the regulation of cardiac metabolism and protection against cardiac lipotoxicity.
Collapse
|
7
|
Fillmore N, Lopaschuk GD. Malonyl CoA: A promising target for the treatment of cardiac disease. IUBMB Life 2014; 66:139-146. [DOI: 10.1002/iub.1253] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 02/14/2014] [Indexed: 12/18/2022]
Affiliation(s)
- Natasha Fillmore
- Cardiovascular Research Centre; Mazankowski Alberta Heart Institute; University of Alberta; Edmonton AB Canada
| | - Gary D. Lopaschuk
- Cardiovascular Research Centre; Mazankowski Alberta Heart Institute; University of Alberta; Edmonton AB Canada
| |
Collapse
|
8
|
Wende AR, Symons JD, Abel ED. Mechanisms of lipotoxicity in the cardiovascular system. Curr Hypertens Rep 2013; 14:517-31. [PMID: 23054891 DOI: 10.1007/s11906-012-0307-2] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cardiovascular diseases account for approximately one third of all deaths globally. Obese and diabetic patients have a high likelihood of dying from complications associated with cardiovascular dysfunction. Obesity and diabetes increase circulating lipids that upon tissue uptake, may be stored as triglyceride, or may be metabolized in other pathways, leading to the generation of toxic intermediates. Excess lipid utilization or activation of signaling pathways by lipid metabolites may disrupt cellular homeostasis and contribute to cell death, defining the concept of lipotoxicity. Lipotoxicity occurs in multiple organs, including cardiac and vascular tissues, and a number of specific mechanisms have been proposed to explain lipotoxic tissue injury. In addition, recent data suggests that increased tissue lipids may also be protective in certain contexts. This review will highlight recent progress toward elucidating the relationship between nutrient oversupply, lipotoxicity, and cardiovascular dysfunction. The review will focus in two sections on the vasculature and cardiomyocytes respectively.
Collapse
Affiliation(s)
- Adam R Wende
- Program in Molecular Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Utah School of Medicine, Salt Lake City, 84112, USA
| | | | | |
Collapse
|
9
|
Lewandowski ED, Fischer SK, Fasano M, Banke NH, Walker LA, Huqi A, Wang X, Lopaschuk GD, O'Donnell JM. Acute liver carnitine palmitoyltransferase I overexpression recapitulates reduced palmitate oxidation of cardiac hypertrophy. Circ Res 2012; 112:57-65. [PMID: 22982985 DOI: 10.1161/circresaha.112.274456] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
RATIONALE Muscle carnitine palmitoyltransferase I is predominant in the heart, but the liver isoform (liver carnitine palmitoyltransferase I [L-CPT1]) is elevated in hearts with low long chain fatty acid oxidation, such as fetal and hypertrophied hearts. OBJECTIVE This work examined the effect of acute L-CPT1 expression on the regulation of palmitate oxidation and energy metabolism in intact functioning rat hearts for comparison with findings in hypertrophied hearts. METHODS AND RESULTS L-CPT1 was expressed in vivo in rat hearts by coronary perfusion of Adv.cmv.L-CPT1 (L-CPT1, n=15) vs. phosphate-buffered saline (PBS) infusion (PBS, n=7) or empty virus (empty, n=5). L-CPT1 was elevated 5-fold at 72 hours after Adv.cmv.L-CPT1 infusion (P<0.05), but muscle carnitine palmitoyltransferase I was unaffected. Despite similar tricarboxylic acid cycle rates, palmitate oxidation rates were reduced with L-CPT1 (1.12 ± 0.29 μmol/min per gram of dry weight, mean±SE) vs. PBS (1.6 ± 0.34). Acetyl CoA production from palmitate was reduced with L-CPT1 (69 ± 0.02%; P<0.05; PBS=79 ± 0.01%; empty=81 ± 0.02%), similar to what occurs in hypertrophied hearts, and with no difference in malonyl CoA content. Glucose oxidation was elevated with L-CPT1 (by 60%). Surprisingly, L-CPT1 hearts contained elevated atrial natriuretic peptide, indicating induction of hypertrophic signaling. CONCLUSIONS The results link L-CPT1 expression to reduced palmitate oxidation in a nondiseased adult heart, recapitulating the phenotype of reduced long chain fatty acid oxidation in cardiac hypertrophy. The implications are that L-CPT1 expression induces metabolic remodeling hypertrophic signaling and that regulatory factors beyond malonyl CoA in the heart regulate long chain fatty acid oxidation via L-CPT1.
Collapse
Affiliation(s)
- E Douglas Lewandowski
- Center for Cardiovascular Research, UIC College of Medicine, 909 South Wolcott Ave, MC 801, Chicago, IL 60612, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
The Canadian Diabetes Association Invests More than $7 Million in Research. Can J Diabetes 2012. [DOI: 10.1016/j.jcjd.2012.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
11
|
Witham W, Yester K, O'Donnell CP, McGaffin KR. Restoration of glucose metabolism in leptin-resistant mouse hearts after acute myocardial infarction through the activation of survival kinase pathways. J Mol Cell Cardiol 2012; 53:91-100. [PMID: 22507542 DOI: 10.1016/j.yjmcc.2012.03.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 03/26/2012] [Accepted: 03/28/2012] [Indexed: 02/07/2023]
Abstract
In the normal heart, leptin modulates cardiac metabolism. It is unknown, however, what effect leptin has on cardiac metabolism and outcomes in acute myocardial infarction (MI). This study was performed to test the hypothesis that leptin signaling increases glucose metabolism and attenuates injury in the acutely infarcted heart. Mice with (ObR(+/+)) and without (ObR(-/-)) cardiomyocyte specific expression of leptin receptor (ObR) were randomly assigned to experimental MI or sham procedure, and studied 3 days later. ObR(+/+) and ObR(-/-) sham mice were not significantly different in any measured outcome. However, after MI, ObR(-/-) mice had greater cardiac dysfunction, left ventricular dilation, and levels of oxidative stress. These worse indices of cardiac injury in ObR(-/-) mice were associated with attenuated signal transducer and activator of transcription (STAT) 3, phosphatidylinositol-3-kinase (PI3K), and Akt signaling, decreased malonyl CoA content, and reduced mitochondrial pyruvate dehydrogenase and electron transport Complex I, II and IV activities. Furthermore, ObR(-/-) mice maintained high rates of cardiac fatty acid oxidation after MI, whereas ObR(+/+) mice demonstrated a switch away from fatty acid oxidation to glucose metabolism. Restoration of cardiac STAT3, PI3K and Akt activity and mitochondrial function in ObR(-/-) mice post-MI was accomplished by ciliary neurotrophic factor (CNTF), an established STAT3 activator, administered immediately after MI. Moreover, CNTF therapy resulted in mitigation of cardiac structural and functional injury, attenuated levels of oxidative stress, and rescued glucose metabolism in the infarcted ObR(-/-) heart. These data demonstrate that impaired cardiac leptin signaling results in metabolic inflexibility for glucose utilization in the face of cardiac stress, and greater morbidity after MI. Further, these studies show that cardiac glucose metabolism can be restored in leptin-resistant hearts by CNTF-mediated activation of survival kinases, resulting in multiple improved structural and functional outcomes post-MI.
Collapse
Affiliation(s)
- William Witham
- Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | | | | | | |
Collapse
|
12
|
Abel ED, Sweeney G. Modulation of the cardiovascular system by leptin. Biochimie 2012; 94:2097-103. [PMID: 22490727 DOI: 10.1016/j.biochi.2012.03.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 03/26/2012] [Indexed: 01/20/2023]
Abstract
It is well established that individuals with the metabolic syndrome have a significantly increased risk of cardiovascular disease and much effort has been expended to elicit the underlying mechanisms. Various studies have proposed that excessive or deficient physiological effects mediated by leptin make an important contribution, yet many paradoxical observations often preclude a clear definition of the role of leptin. This review article will briefly discuss principal and most recent evidence on direct and indirect regulation of the cardiovascular system by leptin, focusing on cardiac structural and functional as well as vascular effects.
Collapse
Affiliation(s)
- E Dale Abel
- Division of Endocrinology, Metabolism and Diabetes and Program in Molecular Medicine, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | | |
Collapse
|
13
|
Keung W, Palaniyappan A, Lopaschuk GD. Chronic central leptin decreases food intake and improves glucose tolerance in diet-induced obese mice independent of hypothalamic malonyl CoA levels and skeletal muscle insulin sensitivity. Endocrinology 2011; 152:4127-37. [PMID: 21914780 DOI: 10.1210/en.2011-1254] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although acute leptin administration in the hypothalamus decreases food intake and increases peripheral energy metabolism, the peripheral actions of central chronic leptin administration are less understood. In this study, we investigated what effects chronic (7 d) intracerebroventricular (ICV) administration of leptin has on energy metabolism and insulin sensitivity in diet-induced obese mice. C57/BL mice were fed a low-fat diet (LFD; 10% total calories) or high-fat diet (HFD; 60% total calories) for 8 wk after which leptin was administered ICV for 7 consecutive days. Mice fed a HFD showed signs of insulin resistance, as evidenced by an impaired glucose tolerance test. Chronic leptin treatment resulted in a decrease in food intake and body weight and normalization of glucose clearance but no improvement in insulin sensitivity. Chronic ICV leptin increased hypothalamic signal transducer and activator of transcription-3 and AMP-activated protein kinase phosphorylation but did not change hypothalamic malonyl CoA levels in HFD fed and LFD-fed mice. In the gastrocnemius muscles, the levels of malonyl CoA in both leptin-treated groups were lower than their respective control groups, suggesting an increase in fatty acid oxidation. However, only in the muscles of ICV leptin-treated LFD mice was there a decrease in lipid metabolites including diacylglycerol, triacylglycerol, and ceramide. Our results suggest that chronic ICV leptin decreases food consumption and body weight via a mechanism different from acute ICV leptin administration. Although chronic ICV leptin treatment in HFD mice improves glucose tolerance, this occurs independent of changes in insulin sensitivity in the muscles of HFD mice.
Collapse
Affiliation(s)
- Wendy Keung
- Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
| | | | | |
Collapse
|