1
|
Lygate CA. Maintaining energy provision in the heart: the creatine kinase system in ischaemia-reperfusion injury and chronic heart failure. Clin Sci (Lond) 2024; 138:491-514. [PMID: 38639724 DOI: 10.1042/cs20230616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/25/2024] [Accepted: 04/11/2024] [Indexed: 04/20/2024]
Abstract
The non-stop provision of chemical energy is of critical importance to normal cardiac function, requiring the rapid turnover of ATP to power both relaxation and contraction. Central to this is the creatine kinase (CK) phosphagen system, which buffers local ATP levels to optimise the energy available from ATP hydrolysis, to stimulate energy production via the mitochondria and to smooth out mismatches between energy supply and demand. In this review, we discuss the changes that occur in high-energy phosphate metabolism (i.e., in ATP and phosphocreatine) during ischaemia and reperfusion, which represents an acute crisis of energy provision. Evidence is presented from preclinical models that augmentation of the CK system can reduce ischaemia-reperfusion injury and improve functional recovery. Energetic impairment is also a hallmark of chronic heart failure, in particular, down-regulation of the CK system and loss of adenine nucleotides, which may contribute to pathophysiology by limiting ATP supply. Herein, we discuss the evidence for this hypothesis based on preclinical studies and in patients using magnetic resonance spectroscopy. We conclude that the correlative evidence linking impaired energetics to cardiac dysfunction is compelling; however, causal evidence from loss-of-function models remains equivocal. Nevertheless, proof-of-principle studies suggest that augmentation of CK activity is a therapeutic target to improve cardiac function and remodelling in the failing heart. Further work is necessary to translate these findings to the clinic, in particular, a better understanding of the mechanisms by which the CK system is regulated in disease.
Collapse
Affiliation(s)
- Craig A Lygate
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom
| |
Collapse
|
2
|
Liu M, Li M, Ruan J, Jia J, Ge C, Cao W. Analysis of microRNA Expression Profiles in Broiler Muscle Tissues by Feeding Different Levels of Guanidinoacetic Acid. Curr Issues Mol Biol 2024; 46:3713-3728. [PMID: 38666961 PMCID: PMC11048799 DOI: 10.3390/cimb46040231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/13/2024] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
The aim of this study was to explore the molecular mechanisms through which different levels of GAA affect chicken muscle development by influencing miRNA expression, to lay a theoretical foundation for the identification of key functional small RNAs related to poultry muscle development, and to provide new insights into the regulatory mechanisms of GAA on muscle development and meat quality in broilers. It provides a new theoretical basis for using GAA as a feed additive to improve feed performance. Small RNA sequencing technology was utilized to obtain the expression profiles of miRNA in the broiler pectoral muscle fed with different levels of GAA (0 g/kg, 1.2 g/kg and 3.6 g/kg). An analysis of differentially expressed miRNAs revealed 90 such miRNAs in the three combination comparisons, with gga-miR-130b-5p exhibiting significant differences across all three combinations. Furthermore, three of the differentially expressed miRNAs were performed by RT-qPCR verification, yielding results consistent with those obtained from small RNA sequencing. Target gene prediction, as well as the GO and KEGG enrichment analysis of differentially expressed miRNAs, indicated their involvement in muscle cell differentiation and other processes, particularly those associated with the MAPK signaling pathway. This study has, thus, provided valuable insights and resources for the further exploration of the miRNA molecular mechanism underlying the influence of guanidine acetic acid on broiler muscle development. Combined with previous studies and small RNA sequencing, adding 1.2 g/kg GAA to the diet can better promote the muscle development of broilers.
Collapse
Affiliation(s)
- Mengqian Liu
- College of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China; (M.L.); (M.L.); (J.R.)
| | - Mengyuan Li
- College of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China; (M.L.); (M.L.); (J.R.)
| | - Jinrui Ruan
- College of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China; (M.L.); (M.L.); (J.R.)
| | - Junjing Jia
- College of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China; (M.L.); (M.L.); (J.R.)
- Yunnan Provincial Key Laboratory of Animal Nutrition and Feed, Yunnan Agricultural University, Kunming 650201, China
| | - Changrong Ge
- College of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China; (M.L.); (M.L.); (J.R.)
- Yunnan Provincial Key Laboratory of Animal Nutrition and Feed, Yunnan Agricultural University, Kunming 650201, China
| | - Weina Cao
- College of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China; (M.L.); (M.L.); (J.R.)
- Yunnan Provincial Key Laboratory of Animal Nutrition and Feed, Yunnan Agricultural University, Kunming 650201, China
| |
Collapse
|
3
|
Branovets J, Soodla K, Vendelin M, Birkedal R. Rat and mouse cardiomyocytes show subtle differences in creatine kinase expression and compartmentalization. PLoS One 2023; 18:e0294718. [PMID: 38011179 PMCID: PMC10681188 DOI: 10.1371/journal.pone.0294718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 11/06/2023] [Indexed: 11/29/2023] Open
Abstract
Creatine kinase (CK) and adenylate kinase (AK) are energy transfer systems. Different studies on permeabilized cardiomyocytes suggest that ADP-channelling from mitochondrial CK alone stimulates respiration to its maximum, VO2_max, in rat but not mouse cardiomyocytes. Results are ambiguous on ADP-channelling from AK to mitochondria. This study was undertaken to directly compare the CK and AK systems in rat and mouse hearts. In homogenates, we assessed CK- and AK-activities, and the CK isoform distribution. In permeabilized cardiomyocytes, we assessed mitochondrial respiration stimulated by ADP from CK and AK, VO2_CK and VO2_AK, respectively. The ADP-channelling from CK or AK to mitochondria was assessed by adding PEP and PK to competitively inhibit the respiration rate. We found that rat compared to mouse hearts had a lower aerobic capacity, higher VO2_CK/VO2_max, and different CK-isoform distribution. Although rat hearts had a larger fraction of mitochondrial CK, less ADP was channeled from CK to the mitochondria. This suggests different intracellular compartmentalization in rat and mouse cardiomyocytes. VO2_AK/VO2_max was similar in mouse and rat cardiomyocytes, and AK did not channel ADP to the mitochondria. In the absence of intracellular compartmentalization, the AK- and CK-activities in homogenate should have been similar to the ADP-phosphorylation rates estimated from VO2_AK and VO2_CK in permeabilized cardiomyocytes. Instead, we found that the ADP-phosphorylation rates estimated from permeabilized cardiomyocytes were 2 and 9 times lower than the activities recorded in homogenate for CK and AK, respectively. Our results highlight the importance of energetic compartmentalization in cardiac metabolic regulation and signalling.
Collapse
Affiliation(s)
- Jelena Branovets
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Kärol Soodla
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Marko Vendelin
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Rikke Birkedal
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| |
Collapse
|
4
|
Keidar N, Peretz NK, Yaniv Y. Ca 2+ pushes and pulls energetics to maintain ATP balance in atrial cells: computational insights. Front Physiol 2023; 14:1231259. [PMID: 37528893 PMCID: PMC10387757 DOI: 10.3389/fphys.2023.1231259] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 07/03/2023] [Indexed: 08/03/2023] Open
Abstract
To maintain atrial function, ATP supply-to-demand matching must be tightly controlled. Ca2+ can modulate both energy consumption and production. In light of evidence suggesting that Ca2+ affects energetics through "push" (activating metabolite flux and enzymes in the Krebs cycle to push the redox flux) and "pull" (acting directly on ATP synthase and driving the redox flux through the electron transport chain and increasing ATP production) pathways, we investigated whether both pathways are necessary to maintain atrial ATP supply-to-demand matching. Rabbit right atrial cells were electrically stimulated at different rates, and oxygen consumption and flavoprotein fluorescence were measured. To gain mechanistic insight into the regulators of ATP supply-to-demand matching in atrial cells, models of atrial electrophysiology, Ca2+ cycling and force were integrated with a model of mitochondrial Ca2+ and a modified model of mitochondrial energy metabolism. The experimental results showed that oxygen consumption increased in response to increases in the electrical stimulation rate. The model reproduced these findings and predicted that the increase in oxygen consumption is associated with metabolic homeostasis. The model predicted that Ca2+ must act both in "push" and "pull" pathways to increase oxygen consumption. In contrast to ventricular trabeculae, no rapid time-dependent changes in mitochondrial flavoprotein fluorescence were measured upon an abrupt change in workload. The model reproduced these findings and predicted that the maintenance of metabolic homeostasis is due to the effects of Ca2+ on ATP production. Taken together, this work provides evidence of Ca2+ "push" and "pull" activity to maintain metabolic homeostasis in atrial cells.
Collapse
|
5
|
Wang J, Tian Y, Wei J, Lyu C, Yu H, Song Y. Impacts of dibutyl phthalate on bacterial community composition and carbon and nitrogen metabolic pathways in a municipal wastewater treatment system. ENVIRONMENTAL RESEARCH 2023; 223:115378. [PMID: 36709875 DOI: 10.1016/j.envres.2023.115378] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/13/2023] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
Dibutyl phthalate (DBP) is a typical toxic and hazardous pollutant in pharmaceutical wastewater, affecting the metabolism of microbial flora, leading to decreased treatment efficiency, and deteriorated effluent quality in municipal wastewater treatment plants (WWTPs). This study conducted a long-term experiment with 6 operational stages in a pilot-scale A2O-MBR system, analyzing the effect of DBP on the bacterial community and their carbon and nitrogen metabolic pathways. 16S rRNA gene amplicon sequencing analysis and principal components analysis (PCA) showed that DBP at 8 mg/L significantly influenced the structure of bacterial community (P < 0.05), resulting in reduced bacterial community diversity. Metagenomic analysis was used to explore the embedded carbon and nitrogen metabolic pathways. At the presence of DBP, the metabolism of saccharides, lipids, and aromatic compounds were blocked owing to the vanishment of key enzyme (such as acetylaminohexosyltransferase (EC 2.4.1.92) and UDP-sugar pyro phosphorylase (EC 2.7.7.64)) encoding genes, resulting in weakened carbon metabolism, and thus reduced COD removal performance. The resultant deficiency of the genes such as those encoding hydroxyproline dehydrogenase (EC 1.5.5.3) gave rise to interrupted metabolic pathways of amino acid (arginine, proline, tyrosine, and tryptophan), resulting in declined function of nitrogen metabolism and thus reduced TN removal efficiency. The uncovery of the mechanisms by which DBP affects wastewater treatment system efficiency and microbial metabolism is of theoretical importance for the efficient operation of municipal and pharmaceutical wastewater treatment systems.
Collapse
Affiliation(s)
- Jian Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China
| | - Yucheng Tian
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China; School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China
| | - Jian Wei
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
| | - Chunjian Lyu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Huibin Yu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Yonghui Song
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
| |
Collapse
|
6
|
Gupta A. Cardiac 31P MR spectroscopy: development of the past five decades and future vision-will it be of diagnostic use in clinics? Heart Fail Rev 2023; 28:485-532. [PMID: 36427161 DOI: 10.1007/s10741-022-10287-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/16/2022] [Indexed: 11/27/2022]
Abstract
In the past five decades, the use of the magnetic resonance (MR) technique for cardiovascular diseases has engendered much attention and raised the opportunity that the technique could be useful for clinical applications. MR has two arrows in its quiver: One is magnetic resonance imaging (MRI), and the other is magnetic resonance spectroscopy (MRS). Non-invasively, highly advanced MRI provides unique and profound information about the anatomical changes of the heart. Excellently developed MRS provides irreplaceable and insightful evidence of the real-time biochemistry of cardiac metabolism of underpinning diseases. Compared to MRI, which has already been successfully applied in routine clinical practice, MRS still has a long way to travel to be incorporated into routine diagnostics. Considering the exceptional potential of 31P MRS to measure the real-time metabolic changes of energetic molecules qualitatively and quantitatively, how far its powerful technique should be waited before a successful transition from "bench-to-bedside" is enticing. The present review highlights the seminal studies on the chronological development of cardiac 31P MRS in the past five decades and the future vision and challenges to incorporating it for routine diagnostics of cardiovascular disease.
Collapse
Affiliation(s)
- Ashish Gupta
- Centre of Biomedical Research, SGPGIMS Campus, Lucknow, 226014, India.
| |
Collapse
|
7
|
Abstract
PURPOSE OF REVIEW Myocardial metabolism is intricately linked to cardiac function. Perturbations of cardiac energy metabolism result in an energy-starved heart and the development of contractile dysfunction. In this review, we discuss alterations in myocardial energy supply, transcriptional changes in response to different energy demands, and mitochondrial function in the development of heart failure. RECENT FINDINGS Recent studies on substrate modulation through modifying energy substrate supply have shown cardioprotective properties. In addition, large cardiovascular outcome trials of anti-diabetic agents have demonstrated prognostic benefit, suggesting the importance of myocardial metabolism in cardiac function. Understanding molecular and transcriptional controls of cardiac metabolism promises new research avenues for metabolic treatment targets. Future studies assessing the impact of substrate modulation on cardiac energetic status and function will better inform development of metabolic therapies.
Collapse
Affiliation(s)
- Sher May Ng
- Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK
| | - Stefan Neubauer
- Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK
- Department of Cardiology, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Oliver J Rider
- Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK.
- Department of Cardiology, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
| |
Collapse
|
8
|
Meera P, Uusi-Oukari M, Wallner M, Lipshutz GS. Guanidinoacetate (GAA) is a potent GABA A receptor GABA mimetic: Implications for neurological disease pathology. J Neurochem 2023; 165:445-454. [PMID: 36726215 DOI: 10.1111/jnc.15774] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/24/2023] [Accepted: 01/28/2023] [Indexed: 02/03/2023]
Abstract
Impairment of excretion and enzymatic processing of nitrogen, for example, because of liver or kidney failure, or with urea cycle and creatine synthesis enzyme defects, surprisingly leads to primarily neurologic symptoms, yet the exact mechanisms remain largely mysterious. In guanidinoacetate N-methyltransferase (GAMT) deficiency, the guanidino compound guanidinoacetate (GAA) increases dramatically, including in the cerebrospinal fluid (CSF), and has been implicated in mediating the neurological symptoms in GAMT-deficient patients. GAA is synthesized by arginine-glycine amidinotransferase (AGAT), a promiscuous enzyme that not only transfers the amidino group from arginine to glycine, but also to primary amines in, for example, GABA and taurine to generate γ-guanidinobutyric acid (γ-GBA) and guanidinoethanesulfonic acid (GES), respectively. We show that GAA, γ-GBA, and GES share structural similarities with GABA, evoke GABAA receptor (GABAA R) mediated currents (whereas creatine [methylated GAA] and arginine failed to evoke discernible currents) in cerebellar granule cells in mouse brain slices and displace the high-affinity GABA-site radioligand [3 H]muscimol in total brain homogenate GABAA Rs. While γ-GBA and GES are GABA agonists and displace [3 H]muscimol (EC50 /IC50 between 10 and 40 μM), GAA stands out as particularly potent in both activating GABAA Rs (EC50 ~6 μM) and also displacing the GABAA R ligand [3 H]muscimol (IC50 ~3 μM) at pathophysiologically relevant concentrations. These findings stress the role of substantially elevated GAA as a primary neurotoxic agent in GAMT deficiency and we discuss the potential role of GAA in arginase (and creatine transporter) deficiency which show a much more modest increase in GAA concentrations yet share the unique hyperexcitability neuropathology with GAMT deficiency. We conclude that orthosteric activation of GABAA Rs by GAA, and potentially other GABAA R mimetic guanidino compounds (GCs) like γ-GBA and GES, interferes with normal inhibitory GABAergic neurotransmission which could mediate, and contribute to, neurotoxicity.
Collapse
Affiliation(s)
- Pratap Meera
- Department of Neurobiology, University of California, Los Angeles, California, USA
| | - Mikko Uusi-Oukari
- Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Turku, Finland
| | - Martin Wallner
- Departments of Surgery, University of California, Los Angeles, California, USA
| | - Gerald S Lipshutz
- Departments of Surgery, University of California, Los Angeles, California, USA.,Molecular & Medical Pharmacology, University of California, Los Angeles, California, USA.,Intellectual and Developmental Disabilities Research Center, University of California, Los Angeles, California, USA.,Semel Institute for Neuroscience, University of California, Los Angeles, California, USA
| |
Collapse
|
9
|
Birkedal R, Laasmaa M, Branovets J, Vendelin M. Ontogeny of cardiomyocytes: ultrastructure optimization to meet the demand for tight communication in excitation-contraction coupling and energy transfer. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210321. [PMID: 36189816 PMCID: PMC9527910 DOI: 10.1098/rstb.2021.0321] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The ontogeny of the heart describes its development from the fetal to the adult stage. In newborn mammals, blood pressure and thus cardiac performance are relatively low. The cardiomyocytes are thin, and with a central core of mitochondria surrounded by a ring of myofilaments, while the sarcoplasmic reticulum (SR) is sparse. During development, as blood pressure and performance increase, the cardiomyocytes become more packed with structures involved in excitation–contraction (e-c) coupling (SR and myofilaments) and the generation of ATP (mitochondria) to fuel the contraction. In parallel, the e-c coupling relies increasingly on calcium fluxes through the SR, while metabolism relies increasingly on fatty acid oxidation. The development of transverse tubules and SR brings channels and transporters interacting via calcium closer to each other and is crucial for e-c coupling. However, for energy transfer, it may seem counterintuitive that the increased structural density restricts the overall ATP/ADP diffusion. In this review, we discuss how this is because of the organization of all these structures forming modules. Although the overall diffusion across modules is more restricted, the energy transfer within modules is fast. A few studies suggest that in failing hearts this modular design is disrupted, and this may compromise intracellular energy transfer. This article is part of the theme issue ‘The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease’.
Collapse
Affiliation(s)
- Rikke Birkedal
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Akadeemia 15, room SCI-218, 12618 Tallinn, Estonia
| | - Martin Laasmaa
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Akadeemia 15, room SCI-218, 12618 Tallinn, Estonia
| | - Jelena Branovets
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Akadeemia 15, room SCI-218, 12618 Tallinn, Estonia
| | - Marko Vendelin
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Akadeemia 15, room SCI-218, 12618 Tallinn, Estonia
| |
Collapse
|
10
|
McAndrew DJ, Lake HA, Zervou S, Schwedhelm E, Schneider JE, Neubauer S, Lygate CA. Homoarginine and creatine deficiency do not exacerbate murine ischaemic heart failure. ESC Heart Fail 2022; 10:189-199. [PMID: 36178450 PMCID: PMC9871656 DOI: 10.1002/ehf2.14183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/23/2022] [Accepted: 09/15/2022] [Indexed: 01/27/2023] Open
Abstract
AIMS Low levels of homoarginine and creatine are associated with heart failure severity in humans, but it is unclear to what extent they contribute to pathophysiology. Both are synthesized via L-arginine:glycine amidinotransferase (AGAT), such that AGAT-/- mice have a combined creatine and homoarginine deficiency. We hypothesized that this would be detrimental in the setting of chronic heart failure. METHODS AND RESULTS Study 1: homoarginine deficiency-female AGAT-/- and wild-type mice were given creatine-supplemented diet so that both had normal myocardial creatine levels, but only AGAT-/- had low plasma homoarginine. Myocardial infarction (MI) was surgically induced and left ventricular (LV) structure and function assessed at 6-7 weeks by in vivo imaging and haemodynamics. Study 2: homoarginine and creatine-deficiency-as before, but AGAT-/- mice were given creatine-supplemented diet until 1 week post-MI, when 50% were changed to a creatine-free diet. Both groups therefore had low homoarginine levels, but one group also developed lower myocardial creatine levels. In both studies, all groups had LV remodelling and dysfunction commensurate with the development of chronic heart failure, for example, LV dilatation and mean ejection fraction <20%. However, neither homoarginine deficiency alone or in combination with creatine deficiency had a significant effect on mortality, LV remodelling, or on any indices of contractile and lusitropic function. CONCLUSIONS Low levels of homoarginine and creatine do not worsen chronic heart failure arguing against a major causative role in disease progression. This suggests that it is unnecessary to correct hArg deficiency in patients with heart failure, although supra-physiological levels may still be beneficial.
Collapse
Affiliation(s)
- Debra J. McAndrew
- Division of Cardiovascular Medicine, Radcliffe Department of MedicineUniversity of OxfordOxfordUK,British Heart Foundation Centre for Research ExcellenceUniversity of OxfordOxfordUK,Wellcome Centre for Human GeneticsRoosevelt DriveOxfordOX3 7BNUK
| | - Hannah A. Lake
- Division of Cardiovascular Medicine, Radcliffe Department of MedicineUniversity of OxfordOxfordUK,British Heart Foundation Centre for Research ExcellenceUniversity of OxfordOxfordUK,Wellcome Centre for Human GeneticsRoosevelt DriveOxfordOX3 7BNUK
| | - Sevasti Zervou
- Division of Cardiovascular Medicine, Radcliffe Department of MedicineUniversity of OxfordOxfordUK,British Heart Foundation Centre for Research ExcellenceUniversity of OxfordOxfordUK,Wellcome Centre for Human GeneticsRoosevelt DriveOxfordOX3 7BNUK
| | - Edzard Schwedhelm
- Institute of Clinical Pharmacology and ToxicologyUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Jurgen E. Schneider
- Division of Cardiovascular Medicine, Radcliffe Department of MedicineUniversity of OxfordOxfordUK,Experimental and Preclinical Imaging Centre (ePIC), Leeds Institute of Cardiovascular and Metabolic MedicineUniversity of LeedsLeedsUK
| | - Stefan Neubauer
- Division of Cardiovascular Medicine, Radcliffe Department of MedicineUniversity of OxfordOxfordUK,British Heart Foundation Centre for Research ExcellenceUniversity of OxfordOxfordUK
| | - Craig A. Lygate
- Division of Cardiovascular Medicine, Radcliffe Department of MedicineUniversity of OxfordOxfordUK,British Heart Foundation Centre for Research ExcellenceUniversity of OxfordOxfordUK,Wellcome Centre for Human GeneticsRoosevelt DriveOxfordOX3 7BNUK
| |
Collapse
|
11
|
Keceli G, Gupta A, Sourdon J, Gabr R, Schär M, Dey S, Tocchetti CG, Stuber A, Agrimi J, Zhang Y, Leppo M, Steenbergen C, Lai S, Yanek LR, O’Rourke B, Gerstenblith G, Bottomley PA, Wang Y, Paolocci N, Weiss RG. Mitochondrial Creatine Kinase Attenuates Pathologic Remodeling in Heart Failure. Circ Res 2022; 130:741-759. [PMID: 35109669 PMCID: PMC8897235 DOI: 10.1161/circresaha.121.319648] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Abnormalities in cardiac energy metabolism occur in heart failure (HF) and contribute to contractile dysfunction, but their role, if any, in HF-related pathologic remodeling is much less established. CK (creatine kinase), the primary muscle energy reserve reaction which rapidly provides ATP at the myofibrils and regenerates mitochondrial ADP, is down-regulated in experimental and human HF. We tested the hypotheses that pathologic remodeling in human HF is related to impaired cardiac CK energy metabolism and that rescuing CK attenuates maladaptive hypertrophy in experimental HF. METHODS First, in 27 HF patients and 14 healthy subjects, we measured cardiac energetics and left ventricular remodeling using noninvasive magnetic resonance 31P spectroscopy and magnetic resonance imaging, respectively. Second, we tested the impact of metabolic rescue with cardiac-specific overexpression of either Ckmyofib (myofibrillar CK) or Ckmito (mitochondrial CK) on HF-related maladaptive hypertrophy in mice. RESULTS In people, pathologic left ventricular hypertrophy and dilatation correlate closely with reduced myocardial ATP levels and rates of ATP synthesis through CK. In mice, transverse aortic constriction-induced left ventricular hypertrophy and dilatation are attenuated by overexpression of CKmito, but not by overexpression of CKmyofib. CKmito overexpression also attenuates hypertrophy after chronic isoproterenol stimulation. CKmito lowers mitochondrial reactive oxygen species, tissue reactive oxygen species levels, and upregulates antioxidants and their promoters. When the CK capacity of CKmito-overexpressing mice is limited by creatine substrate depletion, the protection against pathologic remodeling is lost, suggesting the ADP regenerating capacity of the CKmito reaction rather than CK protein per se is critical in limiting adverse HF remodeling. CONCLUSIONS In the failing human heart, pathologic hypertrophy and adverse remodeling are closely related to deficits in ATP levels and in the CK energy reserve reaction. CKmito, sitting at the intersection of cardiac energetics and redox balance, plays a crucial role in attenuating pathologic remodeling in HF. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00181259.
Collapse
Affiliation(s)
- Gizem Keceli
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Ashish Gupta
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Joevin Sourdon
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Refaat Gabr
- Department of Diagnostic and Interventional Imaging, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, US
| | - Michael Schär
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Swati Dey
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, US
| | - Carlo G. Tocchetti
- Department of Translational Medical Sciences, Interdepartmental Center for Clinical and Translational Research (CIRCET), Interdepartmental Hypertension Research Center (CIRIAPA), Federico II University, Naples, Italy
| | - Annina Stuber
- École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Jacopo Agrimi
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Yi Zhang
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Michelle Leppo
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Charles Steenbergen
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD US
| | - Shenghan Lai
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, US
| | - Lisa R. Yanek
- Division of General Internal Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Brian O’Rourke
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Gary Gerstenblith
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Paul A. Bottomley
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Yibin Wang
- Departments of Anesthesiology and Medicine, University of California at Los Angeles, Los Angeles, CA, US
| | - Nazareno Paolocci
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Robert G. Weiss
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, US
| |
Collapse
|
12
|
Koch V, Weber C, Riffel JH, Buchner K, Buss SJ, Hein S, Mereles D, Hagenmueller M, Erbel C, März W, Booz C, Albrecht MH, Vogl TJ, Frey N, Hardt SE, Ochs M. Impact of Homoarginine on Myocardial Function and Remodeling in a Rat Model of Chronic Renal Failure. J Cardiovasc Pharmacol Ther 2022; 27:10742484211054620. [PMID: 34994208 DOI: 10.1177/10742484211054620] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE Low plasma concentrations of the amino acid homoarginine (HA) have been shown to correlate with adverse cardiovascular outcome, particularly in patients with chronic kidney disease. The present study sought to investigate the effect of HA treatment on cardiac remodeling in rats undergoing artificially induced renal insufficiency by 5/6 nephrectomy (5/6 Nx). METHODS A total of 33 male Wistar rats were randomly divided into sham and 5/6 Nx groups, receiving either placebo treatment or 400 mg·kg-1·day-1 HA over a 4-week period. RESULTS 5/6 Nx per se resulted in adverse myocardial remodeling with aggravated cardiac function and associated cardiac overload as the most obvious alteration (-23% ejection fraction, P < 0.0001), as well as increased myocardial fibrosis (+80%, P = 0.0005) compared to placebo treated sham animals. HA treatment of 5/6 Nx rats has led to an improvement of ejection fraction (+24%, P = 0.0003) and fractional shortening (+21%, P = 0.0126), as well as a decrease of collagen deposition (-32%, P = 0.0041), left ventricular weight (-14%, P = 0.0468), and myocyte cross-sectional area (-12%, P < 0.0001). These changes were accompanied by a downregulation of atrial natriuretic factor (-65% P < 0.0001) and collagen type V alpha 1 chain (-44%, P = 0.0006). Sham animals revealed no significant changes in cardiac function, myocardial fibrosis, or any of the aforementioned molecular changes after drug treatment. CONCLUSION Dietary HA supplementation appears to have the potential of preventing cardiac remodeling and improving heart function in the setting of chronic kidney disease. Our findings shed new light on HA as a possible new therapeutic agent for patients at high cardiovascular risk.
Collapse
Affiliation(s)
- Vitali Koch
- Department of Cardiology, Angiology and Pulmonology, 27178Heidelberg University Hospital, Heidelberg, Germany
| | - Christophe Weber
- Department of Cardiology, Angiology and Pulmonology, 27178Heidelberg University Hospital, Heidelberg, Germany
| | - Johannes H Riffel
- Department of Cardiology, Angiology and Pulmonology, 27178Heidelberg University Hospital, Heidelberg, Germany
| | - Kristina Buchner
- Institute of Human Genetics, Section for Developmental Genetics, 27178University of Heidelberg, Heidelberg, Germany
| | - Sebastian J Buss
- Department of Cardiology, Angiology and Pulmonology, 27178Heidelberg University Hospital, Heidelberg, Germany
| | - Selina Hein
- Department of Cardiology, Angiology and Pulmonology, 27178Heidelberg University Hospital, Heidelberg, Germany
| | - Derliz Mereles
- Department of Cardiology, Angiology and Pulmonology, 27178Heidelberg University Hospital, Heidelberg, Germany
| | - Marco Hagenmueller
- Department of Cardiology, Angiology and Pulmonology, 27178Heidelberg University Hospital, Heidelberg, Germany
| | - Christian Erbel
- Department of Cardiology, Angiology and Pulmonology, 27178Heidelberg University Hospital, Heidelberg, Germany
| | - Winfried März
- Synlab Academy, Synlab Holding Deutschland GmbH, Augsburg, Germany
| | - Christian Booz
- 9173Goethe University Frankfurt, Frankfurt am Main, Germany
| | | | - Thomas J Vogl
- 9173Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Norbert Frey
- Department of Cardiology, Angiology and Pulmonology, 27178Heidelberg University Hospital, Heidelberg, Germany
| | - Stefan E Hardt
- Department of Cardiology, Angiology and Pulmonology, 27178Heidelberg University Hospital, Heidelberg, Germany
| | - Marco Ochs
- Department of Cardiology, Angiology and Pulmonology, 27178Heidelberg University Hospital, Heidelberg, Germany
| |
Collapse
|
13
|
Li DK, Smith LE, Rookyard AW, Lingam SJ, Koay YC, McEwen HP, Twigg SM, Don AS, O'Sullivan JF, Cordwell SJ, White MY. Multi-omics of a pre-clinical model of diabetic cardiomyopathy reveals increased fatty acid supply impacts mitochondrial metabolic selectivity. J Mol Cell Cardiol 2021; 164:92-109. [PMID: 34826416 DOI: 10.1016/j.yjmcc.2021.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 11/05/2021] [Accepted: 11/09/2021] [Indexed: 02/07/2023]
Abstract
The incidence of type 2 diabetes (T2D) is increasing globally, with long-term implications for human health and longevity. Heart disease is the leading cause of death in T2D patients, who display an elevated risk of an acute cardiovascular event and worse outcomes following such an insult. The underlying mechanisms that predispose the diabetic heart to this poor prognosis remain to be defined. This study developed a pre-clinical model (Rattus norvegicus) that complemented caloric excess from a high-fat diet (HFD) and pancreatic β-cell dysfunction from streptozotocin (STZ) to produce hyperglycaemia, peripheral insulin resistance, hyperlipidaemia and elevated fat mass to mimic the clinical features of T2D. Ex vivo cardiac function was assessed using Langendorff perfusion with systolic and diastolic contractile depression observed in T2D hearts. Cohorts representing untreated, individual HFD- or STZ-treatments and the combined HFD + STZ approach were used to generate ventricular samples (n = 9 per cohort) for sequential and integrated analysis of the proteome, lipidome and metabolome by liquid chromatography-tandem mass spectrometry. This study found that in T2D hearts, HFD treatment primed the metabolome, while STZ treatment was the major driver for changes in the proteome. Both treatments equally impacted the lipidome. Our data suggest that increases in β-oxidation and early TCA cycle intermediates promoted rerouting via 2-oxaloacetate to glutamate, γ-aminobutyric acid and glutathione. Furthermore, we suggest that the T2D heart activates networks to redistribute excess acetyl-CoA towards ketogenesis and incomplete β-oxidation through the formation of short-chain acylcarnitine species. Multi-omics provided a global and comprehensive molecular view of the diabetic heart, which distributes substrates and products from excess β-oxidation, reduces metabolic flexibility and impairs capacity to restore high energy reservoirs needed to respond to and prevent subsequent acute cardiovascular events.
Collapse
Affiliation(s)
- Desmond K Li
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia; School of Medical Sciences, The University of Sydney, Camperdown, Australia
| | - Lauren E Smith
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia; School of Medical Sciences, The University of Sydney, Camperdown, Australia
| | - Alexander W Rookyard
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia; School of Life and Environmental Sciences, Camperdown, The University of Sydney, Australia
| | - Shivanjali J Lingam
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia; School of Medical Sciences, The University of Sydney, Camperdown, Australia
| | - Yen C Koay
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia; Sydney Medical School, The University of Sydney, Camperdown, Australia; Heart Research Institute, Newtown, Australia
| | - Holly P McEwen
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia; Centenary Institute, The University of Sydney, Camperdown, Australia
| | - Stephen M Twigg
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia; Sydney Medical School, The University of Sydney, Camperdown, Australia; Department of Endocrinology, Royal Prince Alfred Hospital, Camperdown, Australia
| | - Anthony S Don
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia; School of Medical Sciences, The University of Sydney, Camperdown, Australia; Centenary Institute, The University of Sydney, Camperdown, Australia
| | - John F O'Sullivan
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia; Sydney Medical School, The University of Sydney, Camperdown, Australia; Heart Research Institute, Newtown, Australia; Department of Cardiology, Royal Prince Alfred Hospital, Camperdown, Australia
| | - Stuart J Cordwell
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia; School of Medical Sciences, The University of Sydney, Camperdown, Australia; School of Life and Environmental Sciences, Camperdown, The University of Sydney, Australia; Sydney Mass Spectrometry, The University of Sydney, Camperdown, Australia
| | - Melanie Y White
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia; School of Medical Sciences, The University of Sydney, Camperdown, Australia.
| |
Collapse
|
14
|
Willingham TB, Ajayi PT, Glancy B. Subcellular Specialization of Mitochondrial Form and Function in Skeletal Muscle Cells. Front Cell Dev Biol 2021; 9:757305. [PMID: 34722542 PMCID: PMC8554132 DOI: 10.3389/fcell.2021.757305] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/27/2021] [Indexed: 11/22/2022] Open
Abstract
Across different cell types and within single cells, mitochondria are heterogeneous in form and function. In skeletal muscle cells, morphologically and functionally distinct subpopulations of mitochondria have been identified, but the mechanisms by which the subcellular specialization of mitochondria contributes to energy homeostasis in working muscles remains unclear. Here, we discuss the current data regarding mitochondrial heterogeneity in skeletal muscle cells and highlight potential new lines of inquiry that have emerged due to advancements in cellular imaging technologies.
Collapse
Affiliation(s)
- T. Bradley Willingham
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Peter T. Ajayi
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Brian Glancy
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, United States
| |
Collapse
|
15
|
Abstract
Impaired cardiac energy metabolism has been proposed as a mechanism common to different heart failure aetiologies. The energy-depletion hypothesis was pursued by several researchers, and is still a topic of considerable interest. Unlike most organs, in the heart, the creatine kinase system represents a major component of the metabolic machinery, as it functions as an energy shuttle between mitochondria and cytosol. In heart failure, the decrease in creatine level anticipates the reduction in adenosine triphosphate, and the degree of myocardial phosphocreatine/adenosine triphosphate ratio reduction correlates with disease severity, contractile dysfunction, and myocardial structural remodelling. However, it remains to be elucidated whether an impairment of phosphocreatine buffer activity contributes to the pathophysiology of heart failure and whether correcting this energy deficit might prove beneficial. The effects of creatine deficiency and the potential utility of creatine supplementation have been investigated in experimental and clinical models, showing controversial findings. The goal of this article is to provide a comprehensive overview on the role of creatine in cardiac energy metabolism, the assessment and clinical value of creatine deficiency in heart failure, and the possible options for the specific metabolic therapy.
Collapse
|
16
|
Abstract
The design of the energy metabolism system in striated muscle remains a major area of investigation. Here, we review our current understanding and emerging hypotheses regarding the metabolic support of muscle contraction. Maintenance of ATP free energy, so called energy homeostasis, via mitochondrial oxidative phosphorylation is critical to sustained contractile activity, and this major design criterion is the focus of this review. Cell volume invested in mitochondria reduces the space available for generating contractile force, and this spatial balance between mitochondria acontractile elements to meet the varying sustained power demands across muscle types is another important design criterion. This is accomplished with remarkably similar mass-specific mitochondrial protein composition across muscle types, implying that it is the organization of mitochondria within the muscle cell that is critical to supporting sustained muscle function. Beyond the production of ATP, ubiquitous distribution of ATPases throughout the muscle requires rapid distribution of potential energy across these large cells. Distribution of potential energy has long been thought to occur primarily through facilitated metabolite diffusion, but recent analysis has questioned the importance of this process under normal physiological conditions. Recent structural and functional studies have supported the hypothesis that the mitochondrial reticulum provides a rapid energy distribution system via the conduction of the mitochondrial membrane potential to maintain metabolic homeostasis during contractile activity. We extensively review this aspect of the energy metabolism design contrasting it with metabolite diffusion models and how mitochondrial structure can play a role in the delivery of energy in the striated muscle.
Collapse
Affiliation(s)
- Brian Glancy
- Muscle Energetics Laboratory, National Heart, Lung, and Blood Insititute and National Institute of Arthritis and Musculoskeletal and Skin Disease, Bethesda, Maryland
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Insititute, Bethesda, Maryland
| | - Robert S Balaban
- Muscle Energetics Laboratory, National Heart, Lung, and Blood Insititute and National Institute of Arthritis and Musculoskeletal and Skin Disease, Bethesda, Maryland
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Insititute, Bethesda, Maryland
| |
Collapse
|
17
|
Hannemann J, Cordts K, Seniuk A, Choe CU, Schmidt-Hutten L, Duque Escobar J, Weinberger F, Böger R, Schwedhelm E. Arginine:Glycine Amidinotransferase Is Essential for Creatine Supply in Mice During Chronic Hypoxia. Front Physiol 2021; 12:703069. [PMID: 34483959 PMCID: PMC8416470 DOI: 10.3389/fphys.2021.703069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/20/2021] [Indexed: 11/18/2022] Open
Abstract
Objective: Chronic hypoxia induces pulmonary and cardiovascular pathologies, including pulmonary hypertension (PH). L-arginine:glycine amidinotransferase (AGAT) is essential for homoarginine (hArg) and guanidinoacetate synthesis, the latter being converted to creatine by guanidinoacetate methyltransferase. Low hArg concentrations are associated with cardiovascular morbidity and predict mortality in patients with PH. We therefore aimed to investigate the survival and cardiac outcome of AGAT knockout (Agat−/−) mice under hypoxia and a possible rescue of the phenotype. Methods:Agat−/− mice and wild-type (WT) littermates were subjected to normoxia or normobaric hypoxia (10% oxygen) for 4 weeks. A subgroup of Agat−/− mice was supplemented with 1% creatine from weaning. Survival, hematocrit, blood lactate and glucose, heart weight-to-tibia length (HW/TL) ratio, hArg plasma concentration, and Agat and Gamt expression in lung, liver, and kidneys were evaluated. Results: After 6 h of hypoxia, blood lactate was lower in Agat−/−-mice as compared to normoxia (p < 0.001). Agat−/− mice died within 2 days of hypoxia, whereas Agat−/− mice supplemented with creatine and WT mice survived until the end of the study. In WT mice, hematocrit (74 ± 4 vs. 55 ± 2%, mean ± SD, p < 0.001) and HW/TL (9.9 ± 1.3 vs. 7.3 ± 0.7 mg/mm, p < 0.01) were higher in hypoxia, while hArg plasma concentration (0.25 ± 0.06 vs. 0.38 ± 0.12 μmol/L, p < 0.01) was lower. Agat and Gamt expressions were differentially downregulated by hypoxia in lung, liver, and kidneys. Conclusion:Agat and Gamt are downregulated in hypoxia. Agat−/− mice are nonviable in hypoxia. Creatine rescues the lethal phenotype, but it does not reduce right ventricular hypertrophy of Agat−/− mice in hypoxia.
Collapse
Affiliation(s)
- Juliane Hannemann
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and Its Health Sequelae, Hamburg, Germany
| | - Kathrin Cordts
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anika Seniuk
- German Centre for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Institute of Cellular and Integrative Physiology, University Medical Center Hamburg, Hamburg, Germany
| | - Chi-Un Choe
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Lena Schmidt-Hutten
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jorge Duque Escobar
- German Centre for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Cardiology, University Heart and Vascular Center, Hamburg, Germany
| | - Florian Weinberger
- Insitute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rainer Böger
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and Its Health Sequelae, Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Edzard Schwedhelm
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| |
Collapse
|
18
|
Yan Z, Yan Z, Liu S, Yin Y, Yang T, Chen Q. Regulative Mechanism of Guanidinoacetic Acid on Skeletal Muscle Development and Its Application Prospects in Animal Husbandry: A Review. Front Nutr 2021; 8:714567. [PMID: 34458310 PMCID: PMC8387576 DOI: 10.3389/fnut.2021.714567] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/22/2021] [Indexed: 12/12/2022] Open
Abstract
Guanidinoacetic acid is the direct precursor of creatine and its phosphorylated derivative phosphocreatine in the body. It is a safe nutritional supplement that can be used to promote muscle growth and development. Improving the growth performance of livestock and poultry and meat quality is the eternal goal of the animal husbandry, and it is also the common demand of today's society and consumers. A large number of experimental studies have shown that guanidinoacetic acid could improve the growth performance of animals, promote muscle development and improve the health of animals. However, the mechanism of how it affects muscle development needs to be further elucidated. This article discusses the physical and chemical properties of guanidinoacetic acid and its synthesis pathway, explores its mechanism of how it promotes muscle development and growth, and also classifies and summarizes the impact of its application in animal husbandry, providing a scientific basis for this application. In addition, this article also proposes future directions for the development of this substance.
Collapse
Affiliation(s)
- Zhaoming Yan
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
| | - Zhaoyue Yan
- Chemistry Department, University of Liverpool, Liverpool, United Kingdom
| | - Shuangli Liu
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
| | - Yunju Yin
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
| | - Tai Yang
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
| | - Qinghua Chen
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
| |
Collapse
|
19
|
Intellectual Disability and Brain Creatine Deficit: Phenotyping of the Genetic Mouse Model for GAMT Deficiency. Genes (Basel) 2021; 12:genes12081201. [PMID: 34440375 PMCID: PMC8391262 DOI: 10.3390/genes12081201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/23/2021] [Accepted: 07/25/2021] [Indexed: 11/17/2022] Open
Abstract
Guanidinoacetate methyltransferase deficiency (GAMT-D) is one of three cerebral creatine (Cr) deficiency syndromes due to pathogenic variants in the GAMT gene (19p13.3). GAMT-D is characterized by the accumulation of guanidinoacetic acid (GAA) and the depletion of Cr, which result in severe global developmental delay (and intellectual disability), movement disorder, and epilepsy. The GAMT knockout (KO) mouse model presents biochemical alterations in bodily fluids, the brain, and muscles, including increased GAA and decreased Cr and creatinine (Crn) levels, which are similar to those observed in humans. At the behavioral level, only limited and mild alterations have been reported, with a large part of analyzed behaviors being unaffected in GAMT KO as compared with wild-type mice. At the cerebral level, decreased Cr and Crn and increased GAA and other guanidine compound levels have been observed. Nevertheless, the effects of Cr deficiency and GAA accumulation on many neurochemical, morphological, and molecular processes have not yet been explored. In this review, we summarize data regarding behavioral and cerebral GAMT KO phenotypes, and focus on uncharted behavioral alterations that are comparable with the clinical symptoms reported in GAMT-D patients, including intellectual disability, poor speech, and autistic-like behaviors, as well as unexplored Cr-induced cerebral alterations.
Collapse
|
20
|
Gherardi G, De Mario A, Mammucari C. The mitochondrial calcium homeostasis orchestra plays its symphony: Skeletal muscle is the guest of honor. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:209-259. [PMID: 34253296 DOI: 10.1016/bs.ircmb.2021.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
Skeletal muscle mitochondria are placed in close proximity of the sarcoplasmic reticulum (SR), the main intracellular Ca2+ store. During muscle activity, excitation of sarcolemma and of T-tubule triggers the release of Ca2+ from the SR initiating myofiber contraction. The rise in cytosolic Ca2+ determines the opening of the mitochondrial calcium uniporter (MCU), the highly selective channel of the inner mitochondrial membrane (IMM), causing a robust increase in mitochondrial Ca2+ uptake. The Ca2+-dependent activation of TCA cycle enzymes increases the synthesis of ATP required for SERCA activity. Thus, Ca2+ is transported back into the SR and cytosolic [Ca2+] returns to resting levels eventually leading to muscle relaxation. In recent years, thanks to the molecular identification of MCU complex components, the role of mitochondrial Ca2+ uptake in the pathophysiology of skeletal muscle has been uncovered. In this chapter, we will introduce the reader to a general overview of mitochondrial Ca2+ accumulation. We will tackle the key molecular players and the cellular and pathophysiological consequences of mitochondrial Ca2+ dyshomeostasis. In the second part of the chapter, we will discuss novel findings on the physiological role of mitochondrial Ca2+ uptake in skeletal muscle. Finally, we will examine the involvement of mitochondrial Ca2+ signaling in muscle diseases.
Collapse
Affiliation(s)
- Gaia Gherardi
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Agnese De Mario
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | | |
Collapse
|
21
|
Lygate CA. The Pitfalls of in vivo Cardiac Physiology in Genetically Modified Mice - Lessons Learnt the Hard Way in the Creatine Kinase System. Front Physiol 2021; 12:685064. [PMID: 34054587 PMCID: PMC8160301 DOI: 10.3389/fphys.2021.685064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 04/22/2021] [Indexed: 12/30/2022] Open
Abstract
In order to fully understand gene function, at some point, it is necessary to study the effects in an intact organism. The creation of the first knockout mouse in the late 1980's gave rise to a revolution in the field of integrative physiology that continues to this day. There are many complex choices when selecting a strategy for genetic modification, some of which will be touched on in this review, but the principal focus is to highlight the potential problems and pitfalls arising from the interpretation of in vivo cardiac phenotypes. As an exemplar, we will scrutinize the field of cardiac energetics and the attempts to understand the role of the creatine kinase (CK) energy buffering and transport system in the intact organism. This story highlights the confounding effects of genetic background, sex, and age, as well as the difficulties in interpreting knockout models in light of promiscuous proteins and metabolic redundancy. It will consider the dose-dependent effects and unintended consequences of transgene overexpression, and the need for experimental rigour in the context of in vivo phenotyping techniques. It is intended that this review will not only bring clarity to the field of cardiac energetics, but also aid the non-expert in evaluating and critically assessing data arising from in vivo genetic modification.
Collapse
Affiliation(s)
- Craig A Lygate
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
22
|
Role of Creatine in the Heart: Health and Disease. Nutrients 2021; 13:nu13041215. [PMID: 33917009 PMCID: PMC8067763 DOI: 10.3390/nu13041215] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/02/2021] [Accepted: 04/03/2021] [Indexed: 12/26/2022] Open
Abstract
Creatine is a key player in heart contraction and energy metabolism. Creatine supplementation (throughout the paper, only supplementation with creatine monohydrate will be reviewed, as this is by far the most used and best-known way of supplementing creatine) increases creatine content even in the normal heart, and it is generally safe. In heart failure, creatine and phosphocreatine decrease because of decreased expression of the creatine transporter, and because phosphocreatine degrades to prevent adenosine triphosphate (ATP) exhaustion. This causes decreased contractility reserve of the myocardium and correlates with left ventricular ejection fraction, and it is a predictor of mortality. Thus, there is a strong rationale to supplement with creatine the failing heart. Pending additional trials, creatine supplementation in heart failure may be useful given data showing its effectiveness (1) against specific parameters of heart failure, and (2) against the decrease in muscle strength and endurance of heart failure patients. In heart ischemia, the majority of trials used phosphocreatine, whose mechanism of action is mostly unrelated to changes in the ergogenic creatine-phosphocreatine system. Nevertheless, preliminary data with creatine supplementation are encouraging, and warrant additional studies. Prevention of cardiac toxicity of the chemotherapy compounds anthracyclines is a novel field where creatine supplementation may also be useful. Creatine effectiveness in this case may be because anthracyclines reduce expression of the creatine transporter, and because of the pleiotropic antioxidant properties of creatine. Moreover, creatine may also reduce concomitant muscle damage by anthracyclines.
Collapse
|
23
|
Branovets J, Karro N, Barsunova K, Laasmaa M, Lygate CA, Vendelin M, Birkedal R. Cardiac expression and location of hexokinase changes in a mouse model of pure creatine deficiency. Am J Physiol Heart Circ Physiol 2021; 320:H613-H629. [PMID: 33337958 DOI: 10.1152/ajpheart.00188.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 11/10/2020] [Accepted: 12/03/2020] [Indexed: 02/06/2023]
Abstract
Creatine kinase (CK) is considered the main phosphotransfer system in the heart, important for overcoming diffusion restrictions and regulating mitochondrial respiration. It is substrate limited in creatine-deficient mice lacking l-arginine:glycine amidinotransferase (AGAT) or guanidinoacetate N-methyltranferase (GAMT). Our aim was to determine the expression, activity, and mitochondrial coupling of hexokinase (HK) and adenylate kinase (AK), as these represent alternative energy transfer systems. In permeabilized cardiomyocytes, we assessed how much endogenous ADP generated by HK, AK, or CK stimulated mitochondrial respiration and how much was channeled to mitochondria. In whole heart homogenates, and cytosolic and mitochondrial fractions, we measured the activities of AK, CK, and HK. Lastly, we assessed the expression of the major HK, AK, and CK isoforms. Overall, respiration stimulated by HK, AK, and CK was ∼25, 90, and 80%, respectively, of the maximal respiration rate, and ∼20, 0, and 25%, respectively, was channeled to the mitochondria. The activity, distribution, and expression of HK, AK, and CK did not change in GAMT knockout (KO) mice. In AGAT KO mice, we found no changes in AK, but we found a higher HK activity in the mitochondrial fraction, greater expression of HK I, but a lower stimulation of respiration by HK. Our findings suggest that mouse hearts depend less on phosphotransfer systems to facilitate ADP flux across the mitochondrial membrane. In AGAT KO mice, which are a model of pure creatine deficiency, the changes in HK may reflect changes in metabolism as well as influence mitochondrial regulation and reactive oxygen species production.NEW & NOTEWORTHY In creatine-deficient AGAT-/- and GAMT-/- mice, the myocardial creatine kinase system is substrate limited. It is unknown whether subcellular localization and mitochondrial ADP channeling by hexokinase and adenylate kinase may compensate as alternative phosphotransfer systems. Our results show no changes in adenylate kinase, which is the main alternative to creatine kinase in heart. However, we found increased expression and activity of hexokinase I in AGAT-/- cardiomyocytes. This could affect mitochondrial regulation and reactive oxygen species production.
Collapse
Affiliation(s)
- Jelena Branovets
- Laboratory of Systems Biology, Institute of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Niina Karro
- Laboratory of Systems Biology, Institute of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Karina Barsunova
- Laboratory of Systems Biology, Institute of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Martin Laasmaa
- Laboratory of Systems Biology, Institute of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Craig A Lygate
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Marko Vendelin
- Laboratory of Systems Biology, Institute of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Rikke Birkedal
- Laboratory of Systems Biology, Institute of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| |
Collapse
|
24
|
Laasmaa M, Branovets J, Barsunova K, Karro N, Lygate CA, Birkedal R, Vendelin M. Altered calcium handling in cardiomyocytes from arginine-glycine amidinotransferase-knockout mice is rescued by creatine. Am J Physiol Heart Circ Physiol 2021; 320:H805-H825. [PMID: 33275525 DOI: 10.1152/ajpheart.00300.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 10/30/2020] [Accepted: 11/23/2020] [Indexed: 01/14/2023]
Abstract
The creatine kinase system facilitates energy transfer between mitochondria and the major ATPases in the heart. Creatine-deficient mice, which lack arginine-glycine amidinotransferase (AGAT) to synthesize creatine and homoarginine, exhibit reduced cardiac contractility. We studied how the absence of a functional CK system influences calcium handling in isolated cardiomyocytes from AGAT-knockouts and wild-type littermates as well as in AGAT-knockout mice receiving lifelong creatine supplementation via the food. Using a combination of whole cell patch clamp and fluorescence microscopy, we demonstrate that the L-type calcium channel (LTCC) current amplitude and voltage range of activation were significantly lower in AGAT-knockout compared with wild-type littermates. Additionally, the inactivation of LTCC and the calcium transient decay were significantly slower. According to our modeling results, these changes can be reproduced by reducing three parameters in knockout mice when compared with wild-type: LTCC conductance, the exchange constant of Ca2+ transfer between subspace and cytosol, and SERCA activity. Because tissue expression of LTCC and SERCA protein were not significantly different between genotypes, this suggests the involvement of posttranslational regulatory mechanisms or structural reorganization. The AGAT-knockout phenotype of calcium handling was fully reversed by dietary creatine supplementation throughout life. Our results indicate reduced calcium cycling in cardiomyocytes from AGAT-knockouts and suggest that the creatine kinase system is important for the development of calcium handling in the heart.NEW & NOTEWORTHY Creatine-deficient mice lacking arginine-glycine amidinotransferase exhibit compromised cardiac function. Here, we show that this is at least partially due to an overall slowing of calcium dynamics. Calcium influx into the cytosol via the L-type calcium current (LTCC) is diminished, and the rate of the sarcoendoplasmic reticulum calcium ATPase (SERCA) pumping calcium back into the sarcoplasmic reticulum is slower. The expression of LTCC and SERCA did not change, suggesting that the changes are regulatory.
Collapse
Affiliation(s)
- Martin Laasmaa
- Laboratory of Systems Biology, Department of Cybernetics, School of Science, Tallinn University of Technology, Tallinn, Estonia
| | - Jelena Branovets
- Laboratory of Systems Biology, Department of Cybernetics, School of Science, Tallinn University of Technology, Tallinn, Estonia
| | - Karina Barsunova
- Laboratory of Systems Biology, Department of Cybernetics, School of Science, Tallinn University of Technology, Tallinn, Estonia
| | - Niina Karro
- Laboratory of Systems Biology, Department of Cybernetics, School of Science, Tallinn University of Technology, Tallinn, Estonia
| | - Craig A Lygate
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, and the British Heart Foundation Centre of Research Excellence, University of Oxford, Tallinn, United Kingdom
| | - Rikke Birkedal
- Laboratory of Systems Biology, Department of Cybernetics, School of Science, Tallinn University of Technology, Tallinn, Estonia
| | - Marko Vendelin
- Laboratory of Systems Biology, Department of Cybernetics, School of Science, Tallinn University of Technology, Tallinn, Estonia
| |
Collapse
|
25
|
Skeletal muscle healing by M1-like macrophages produced by transient expression of exogenous GM-CSF. Stem Cell Res Ther 2020; 11:473. [PMID: 33158459 PMCID: PMC7648431 DOI: 10.1186/s13287-020-01992-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/22/2020] [Indexed: 12/23/2022] Open
Abstract
Background After traumatic skeletal muscle injury, muscle healing is often incomplete and produces extensive fibrosis. The sequence of M1 and M2 macrophage accumulation and the duration of each subtype in the injured area may help to direct the relative extent of fibrogenesis and myogenesis during healing. We hypothesized that increasing the number of M1 macrophages early after traumatic muscle injury would produce more cellular and molecular substrates for myogenesis and fewer substrates for fibrosis, leading to better muscle healing. Methods To test this hypothesis, we transfected skeletal muscle with a plasmid vector to transiently express GM-CSF shortly after injury to drive the polarization of macrophages towards the M1 subset. C57BL/6 mouse tibialis anterior (TA) muscles were injured by contusion and electroporated with uP-mGM, which is a plasmid vector that transiently expresses GM-CSF. Myogenesis, angiogenesis, and fibrosis were evaluated by histology, immunohistochemistry, and RT-qPCR; subpopulations of macrophages by flow cytometry; and muscle functioning by the maximum running speed on the treadmill and the recovery of muscle mass. Results Muscle injury increased the number of local M1-like macrophages and decreased the number of M2-like macrophages on day 4, and uP-mGM treatment enhanced this variation. uP-mGM treatment decreased TGF-β1 protein expression on day 4, and the Sirius Red-positive area decreased from 35.93 ± 15.45% (no treatment) to 2.9% ± 6.5% (p < 0.01) on day 30. uP-mGM electroporation also increased Hgf, Hif1α, and Mtor gene expression; arteriole density; and muscle fiber number during regeneration. The improvement in the quality of the muscle tissue after treatment with uP-mGM affected the increase in the TA muscle mass and the maximum running speed on a treadmill. Conclusion Collectively, our data show that increasing the number of M1-like macrophages immediately after traumatic muscle injury promotes muscle recovery with less fibrosis, and this can be achieved by the transient expression of GM-CSF.
Collapse
|
26
|
Takeuchi A, Matsuoka S. Integration of mitochondrial energetics in heart with mathematical modelling. J Physiol 2020; 598:1443-1457. [DOI: 10.1113/jp276817] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 01/23/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Ayako Takeuchi
- Department of Integrative and Systems PhysiologyFaculty of Medical Sciencesand Life Science Innovation CenterUniversity of Fukui Fukui 910‐1193 Japan
| | - Satoshi Matsuoka
- Department of Integrative and Systems PhysiologyFaculty of Medical Sciencesand Life Science Innovation CenterUniversity of Fukui Fukui 910‐1193 Japan
| |
Collapse
|
27
|
Aksentijević D, Zervou S, Eykyn TR, McAndrew DJ, Wallis J, Schneider JE, Neubauer S, Lygate CA. Age-Dependent Decline in Cardiac Function in Guanidinoacetate- N-Methyltransferase Knockout Mice. Front Physiol 2020; 10:1535. [PMID: 32038270 PMCID: PMC6985570 DOI: 10.3389/fphys.2019.01535] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/05/2019] [Indexed: 01/15/2023] Open
Abstract
Aim Guanidinoacetate N-methyltransferase (GAMT) is the second essential enzyme in creatine (Cr) biosynthesis. Short-term Cr deficiency is metabolically well tolerated as GAMT–/– mice exhibit normal exercise capacity and response to ischemic heart failure. However, we hypothesized long-term consequences of Cr deficiency and/or accumulation of the Cr precursor guanidinoacetate (GA). Methods Cardiac function and metabolic profile were studied in GAMT–/– mice >1 year. Results In vivo LV catheterization revealed lower heart rate and developed pressure in aging GAMT–/– but normal lung weight and survival versus age-matched controls. Electron microscopy indicated reduced mitochondrial volume density in GAMT–/– hearts (P < 0.001), corroborated by lower mtDNA copy number (P < 0.004), and citrate synthase activity (P < 0.05), however, without impaired mitochondrial respiration. Furthermore, myocardial energy stores and key ATP homeostatic enzymes were barely altered, while pathology was unrelated to oxidative stress since superoxide production and protein carbonylation were unaffected. Gene expression of PGC-1α was 2.5-fold higher in GAMT–/– hearts while downstream genes were not activated, implicating a dysfunction in mitochondrial biogenesis signaling. This was normalized by 10 days of dietary Cr supplementation, as were all in vivo functional parameters, however, it was not possible to differentiate whether relief from Cr deficiency or GA toxicity was causative. Conclusion Long-term Cr deficiency in GAMT–/– mice reduces mitochondrial volume without affecting respiratory function, most likely due to impaired biogenesis. This is associated with hemodynamic changes without evidence of heart failure, which may represent an acceptable functional compromise in return for reduced energy demand in aging mice.
Collapse
Affiliation(s)
- Dunja Aksentijević
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine and Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Sevasti Zervou
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine and Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Thomas R Eykyn
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, London, United Kingdom
| | - Debra J McAndrew
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine and Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Julie Wallis
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine and Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Jurgen E Schneider
- Experimental and Preclinical Imaging Centre, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Stefan Neubauer
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine and Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Craig A Lygate
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine and Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
28
|
Overexpression of mitochondrial creatine kinase preserves cardiac energetics without ameliorating murine chronic heart failure. Basic Res Cardiol 2020; 115:12. [PMID: 31925563 PMCID: PMC6954138 DOI: 10.1007/s00395-020-0777-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/02/2020] [Indexed: 01/24/2023]
Abstract
Mitochondrial creatine kinase (Mt-CK) is a major determinant of cardiac energetic status and is down-regulated in chronic heart failure, which may contribute to disease progression. We hypothesised that cardiomyocyte-specific overexpression of Mt-CK would mitigate against these changes and thereby preserve cardiac function. Male Mt-CK overexpressing mice (OE) and WT littermates were subjected to transverse aortic constriction (TAC) or sham surgery and assessed by echocardiography at 0, 3 and 6 weeks alongside a final LV haemodynamic assessment. Regardless of genotype, TAC mice developed progressive LV hypertrophy, dilatation and contractile dysfunction commensurate with pressure overload-induced chronic heart failure. There was a trend for improved survival in OE-TAC mice (90% vs 73%, P = 0.08), however, OE-TAC mice exhibited greater LV dilatation compared to WT and no functional parameters were significantly different under baseline conditions or during dobutamine stress test. CK activity was 37% higher in OE-sham versus WT-sham hearts and reduced in both TAC groups, but was maintained above normal values in the OE-TAC hearts. A separate cohort of mice received in vivo cardiac 31P-MRS to measure high-energy phosphates. There was no difference in the ratio of phosphocreatine-to-ATP in the sham mice, however, PCr/ATP was reduced in WT-TAC but preserved in OE-TAC (1.04 ± 0.10 vs 2.04 ± 0.22; P = 0.007). In conclusion, overexpression of Mt-CK activity prevented the changes in cardiac energetics that are considered hallmarks of a failing heart. This had a positive effect on early survival but was not associated with improved LV remodelling or function during the development of chronic heart failure.
Collapse
|
29
|
Abstract
The heart consumes large amounts of energy in the form of ATP that is continuously replenished by oxidative phosphorylation in mitochondria and, to a lesser extent, by glycolysis. To adapt the ATP supply efficiently to the constantly varying demand of cardiac myocytes, a complex network of enzymatic and signalling pathways controls the metabolic flux of substrates towards their oxidation in mitochondria. In patients with heart failure, derangements of substrate utilization and intermediate metabolism, an energetic deficit, and oxidative stress are thought to underlie contractile dysfunction and the progression of the disease. In this Review, we give an overview of the physiological processes of cardiac energy metabolism and their pathological alterations in heart failure and diabetes mellitus. Although the energetic deficit in failing hearts - discovered >2 decades ago - might account for contractile dysfunction during maximal exertion, we suggest that the alterations of intermediate substrate metabolism and oxidative stress rather than an ATP deficit per se account for maladaptive cardiac remodelling and dysfunction under resting conditions. Treatments targeting substrate utilization and/or oxidative stress in mitochondria are currently being tested in patients with heart failure and might be promising tools to improve cardiac function beyond that achieved with neuroendocrine inhibition.
Collapse
|
30
|
Faller KME, Atzler D, McAndrew DJ, Zervou S, Whittington HJ, Simon JN, Aksentijevic D, Ten Hove M, Choe CU, Isbrandt D, Casadei B, Schneider JE, Neubauer S, Lygate CA. Impaired cardiac contractile function in arginine:glycine amidinotransferase knockout mice devoid of creatine is rescued by homoarginine but not creatine. Cardiovasc Res 2019; 114:417-430. [PMID: 29236952 PMCID: PMC5982714 DOI: 10.1093/cvr/cvx242] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 12/08/2017] [Indexed: 01/09/2023] Open
Abstract
Aims Creatine buffers cellular adenosine triphosphate (ATP) via the creatine kinase reaction. Creatine levels are reduced in heart failure, but their contribution to pathophysiology is unclear. Arginine:glycine amidinotransferase (AGAT) in the kidney catalyses both the first step in creatine biosynthesis as well as homoarginine (HA) synthesis. AGAT-/- mice fed a creatine-free diet have a whole body creatine-deficiency. We hypothesized that AGAT-/- mice would develop cardiac dysfunction and rescue by dietary creatine would imply causality. Methods and results Withdrawal of dietary creatine in AGAT-/- mice provided an estimate of myocardial creatine efflux of ∼2.7%/day; however, in vivo cardiac function was maintained despite low levels of myocardial creatine. Using AGAT-/- mice naïve to dietary creatine we confirmed absence of phosphocreatine in the heart, but crucially, ATP levels were unchanged. Potential compensatory adaptations were absent, AMPK was not activated and respiration in isolated mitochondria was normal. AGAT-/- mice had rescuable changes in body water and organ weights suggesting a role for creatine as a compatible osmolyte. Creatine-naïve AGAT-/- mice had haemodynamic impairment with low LV systolic pressure and reduced inotropy, lusitropy, and contractile reserve. Creatine supplementation only corrected systolic pressure despite normalization of myocardial creatine. AGAT-/- mice had low plasma HA and supplementation completely rescued all other haemodynamic parameters. Contractile dysfunction in AGAT-/- was confirmed in Langendorff perfused hearts and in creatine-replete isolated cardiomyocytes, indicating that HA is necessary for normal cardiac function. Conclusions Our findings argue against low myocardial creatine per se as a major contributor to cardiac dysfunction. Conversely, we show that HA deficiency can impair cardiac function, which may explain why low HA is an independent risk factor for multiple cardiovascular diseases.
Collapse
Affiliation(s)
- Kiterie M E Faller
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence at the University of Oxford and the Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Dorothee Atzler
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence at the University of Oxford and the Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK.,German Centre for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Institute for Cardiovascular Prevention (IPEK), Pettenkoferstraße 8a & 9, 80336 Munich, Germany.,Walther-Straub Institute of Pharmacology and Toxicology, Ludwig Maximilians University, Goethestrasse 33, 80336 Munich, Germany
| | - Debra J McAndrew
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence at the University of Oxford and the Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Sevasti Zervou
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence at the University of Oxford and the Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Hannah J Whittington
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence at the University of Oxford and the Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Jillian N Simon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence at the University of Oxford and the Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Dunja Aksentijevic
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence at the University of Oxford and the Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Michiel Ten Hove
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence at the University of Oxford and the Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Chi-Un Choe
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Dirk Isbrandt
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany.,The Institute for Molecular and Behavioral Neuroscience, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - Barbara Casadei
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence at the University of Oxford and the Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Jurgen E Schneider
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence at the University of Oxford and the Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK.,Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, LS2 9JT, UK
| | - Stefan Neubauer
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence at the University of Oxford and the Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Craig A Lygate
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence at the University of Oxford and the Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| |
Collapse
|
31
|
Affiliation(s)
- Craig A Lygate
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, UK
| |
Collapse
|
32
|
Abstract
Inflammatory processes underlie many diseases associated with injury of the heart muscle, including conditions without an obvious inflammatory pathogenic component such as hypertensive and diabetic cardiomyopathy. Persistence of cardiac inflammation can cause irreversible structural and functional deficits. Some are induced by direct damage of the heart muscle by cellular and soluble mediators but also by metabolic adaptations sustained by the inflammatory microenvironment. It is well established that both cardiomyocytes and immune cells undergo metabolic reprogramming in the site of inflammation, which allow them to deal with decreased availability of nutrients and oxygen. However, like in cancer, competition for nutrients and increased production of signalling metabolites such as lactate initiate a metabolic cross-talk between immune cells and cardiomyocytes which, we propose, might tip the balance between resolution of the inflammation versus adverse cardiac remodeling. Here we review our current understanding of the metabolic reprogramming of both heart tissue and immune cells during inflammation, and we discuss potential key mechanisms by which these metabolic responses intersect and influence each other and ultimately define the prognosis of the inflammatory process in the heart.
Collapse
Affiliation(s)
- Federica M Marelli-Berg
- William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, United Kingdom.,Centre for Inflammation and Therapeutic Innovation, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, United Kingdom
| | - Dunja Aksentijevic
- School of Biological and Chemical Sciences, Queen Mary University of London, G.E. Fogg Building, Mile End Road, London E1 4NS, United Kingdom.,Centre for Inflammation and Therapeutic Innovation, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, United Kingdom
| |
Collapse
|
33
|
Skeletal muscle excitation-metabolism coupling. Arch Biochem Biophys 2019; 664:89-94. [DOI: 10.1016/j.abb.2019.01.037] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/30/2019] [Accepted: 01/31/2019] [Indexed: 01/17/2023]
|
34
|
The creatine kinase system as a therapeutic target for myocardial ischaemia-reperfusion injury. Biochem Soc Trans 2018; 46:1119-1127. [PMID: 30242115 PMCID: PMC6195634 DOI: 10.1042/bst20170504] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 08/18/2018] [Accepted: 08/22/2018] [Indexed: 12/13/2022]
Abstract
Restoring blood flow following an acute myocardial infarction saves lives, but results in tissue damage due to ischaemia–reperfusion injury (I/R). Ameliorating this damage is a major research goal to improve recovery and reduce subsequent morbidity due to heart failure. Both the ischaemic and reperfusion phases represent crises of cellular energy provision in which the mitochondria play a central role. This mini-review will explore the rationale and therapeutic potential of augmenting the creatine kinase (CK) energy shuttle, which constitutes the primary short-term energy buffer and transport system in the cardiomyocyte. Proof-of-principle data from several transgenic mouse models have demonstrated robust cardioprotection by either raising myocardial creatine levels or by overexpressing specific CK isoforms. The effect on cardiac function, high-energy phosphates and myocardial injury will be discussed and possible directions for future research highlighted. We conclude that the CK system represents a viable target for therapeutic intervention in I/R injury; however, much needed translational studies will require the development of new pharmacological tools.
Collapse
|
35
|
Abstract
Isoforms of creatine kinase (CK) generate and use phosphocreatine, a concentrated and highly diffusible cellular "high energy" intermediate, for the main purpose of energy buffering and transfer in order to maintain cellular energy homeostasis. The mitochondrial CK isoform (mtCK) localizes to the mitochondrial intermembrane and cristae space, where it assembles into peripherally membrane-bound, large cuboidal homooctamers. These are part of proteolipid complexes wherein mtCK directly interacts with cardiolipin and other anionic phospholipids, as well as with the VDAC channel in the outer membrane. This leads to a stabilization and cross-linking of inner and outer mitochondrial membrane, forming so-called contact sites. Also the adenine nucleotide translocator of the inner membrane can be recruited into these proteolipid complexes, probably mediated by cardiolipin. The complexes have functions mainly in energy transfer to the cytosol and stimulation of oxidative phosphorylation, but also in restraining formation of reactive oxygen species and apoptosis. In vitro evidence indicates a putative role of mtCK in mitochondrial phospholipid distribution, and most recently a role in thermogenesis has been proposed. This review summarizes the essential structural and functional data of these mtCK complexes and describes in more detail the more recent advances in phospholipid interaction, thermogenesis, cancer and evolution of mtCK.
Collapse
|
36
|
Brewster LM. Creatine kinase, energy reserve, and hypertension: from bench to bedside. ANNALS OF TRANSLATIONAL MEDICINE 2018; 6:292. [PMID: 30211180 PMCID: PMC6123196 DOI: 10.21037/atm.2018.07.15] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 07/11/2018] [Indexed: 12/17/2022]
Abstract
We hypothesized that human variation in the activity of the ATP regenerating enzyme creatine kinase (CK) activity affects hypertension and cardiovascular disease risk. CK is tightly bound close to ATP-utilizing enzymes including Ca2+-ATPase, myosin ATPase, and Na+/K+-ATPase, where it rapidly regenerates ATP from ADP, H+, and phosphocreatine. Thus, relatively high CK was thought to enhance ATP-demanding processes including resistance artery contractility and sodium retention, and reduce ADP-dependent functions. In a series of studies of our group and others, CK was linked to hypertension and bleeding risk. Plasma CK after rest, used as a surrogate measure for tissue CK, was associated with high blood pressure and failure of antihypertensive therapy in case-control and population studies. Importantly, high tissue CK preceded hypertension in animal models and in humans, and human vascular tissue CK gene expression was strongly associated with clinical blood pressure. In line with this, CK inhibition substantially reduced the contractility of human resistance arteries ex vivo. We also presented evidence that plasma CK reduced ADP-dependent platelet aggregation. In subsequent intervention studies, the oral competitive CK inhibitor beta-guanidinopropionic acid (GPA) reduced blood pressure in spontaneously hypertensive rats (SHRs), and a 1-week trial of sub-therapeutic dose GPA in healthy men was uneventful. Thus, based on theoretical concepts, evidence was gathered in laboratory, case-control, and population studies that high CK is associated with hypertension and with bleeding risk, potentially leading to a new mode of cardiovascular risk reduction with CK inhibition.
Collapse
Affiliation(s)
- Lizzy M Brewster
- Department of Cardiovascular Disease, Creatine Kinase Foundation, Amsterdam, The Netherlands
| |
Collapse
|
37
|
Díaz-Vegas AR, Cordova A, Valladares D, Llanos P, Hidalgo C, Gherardi G, De Stefani D, Mammucari C, Rizzuto R, Contreras-Ferrat A, Jaimovich E. Mitochondrial Calcium Increase Induced by RyR1 and IP3R Channel Activation After Membrane Depolarization Regulates Skeletal Muscle Metabolism. Front Physiol 2018; 9:791. [PMID: 29988564 PMCID: PMC6026899 DOI: 10.3389/fphys.2018.00791] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 06/06/2018] [Indexed: 11/13/2022] Open
Abstract
Aim: We hypothesize that both type-1 ryanodine receptor (RyR1) and IP3-receptor (IP3R) calcium channels are necessary for the mitochondrial Ca2+ increase caused by membrane depolarization induced by potassium (or by electrical stimulation) of single skeletal muscle fibers; this calcium increase would couple muscle fiber excitation to an increase in metabolic output from mitochondria (excitation-metabolism coupling). Methods: Mitochondria matrix and cytoplasmic Ca2+ levels were evaluated in fibers isolated from flexor digitorium brevis muscle using plasmids for the expression of a mitochondrial Ca2+ sensor (CEPIA3mt) or a cytoplasmic Ca2+ sensor (RCaMP). The role of intracellular Ca2+ channels was evaluated using both specific pharmacological inhibitors (xestospongin B for IP3R and Dantrolene for RyR1) and a genetic approach (shIP3R1-RFP). O2 consumption was detected using Seahorse Extracellular Flux Analyzer. Results: In isolated muscle fibers cell membrane depolarization increased both cytoplasmic and mitochondrial Ca2+ levels. Mitochondrial Ca2+ uptake required functional inositol IP3R and RyR1 channels. Inhibition of either channel decreased basal O2 consumption rate but only RyR1 inhibition decreased ATP-linked O2 consumption. Cell membrane depolarization-induced Ca2+ signals in sub-sarcolemmal mitochondria were accompanied by a reduction in mitochondrial membrane potential; Ca2+ signals propagated toward intermyofibrillar mitochondria, which displayed increased membrane potential. These results are compatible with slow, Ca2+-dependent propagation of mitochondrial membrane potential from the surface toward the center of the fiber. Conclusion: Ca2+-dependent changes in mitochondrial membrane potential have different kinetics in the surface vs. the center of the fiber; these differences are likely to play a critical role in the control of mitochondrial metabolism, both at rest and after membrane depolarization as part of an “excitation-metabolism” coupling process in skeletal muscle fibers.
Collapse
Affiliation(s)
- Alexis R Díaz-Vegas
- Muscle Physiology Laboratory, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile
| | - Alex Cordova
- Biomedical Neuroscience Institute, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile
| | - Denisse Valladares
- Muscle Physiology Laboratory, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Exercise and Movement Science Laboratory, Universidad Finis Terrae, Santiago, Chile
| | - Paola Llanos
- Muscle Physiology Laboratory, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Institute for Research in Dental Science, Universidad de Chile, Santiago, Chile
| | - Cecilia Hidalgo
- Biomedical Neuroscience Institute, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile
| | - Gaia Gherardi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Ariel Contreras-Ferrat
- Muscle Physiology Laboratory, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile
| | - Enrique Jaimovich
- Muscle Physiology Laboratory, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile
| |
Collapse
|
38
|
Affiliation(s)
| | - Roger Harris
- Formerly University of Chichester, Chichester, UK.
| |
Collapse
|
39
|
Luptak I, Sverdlov AL, Panagia M, Qin F, Pimentel DR, Croteau D, Siwik DA, Ingwall JS, Bachschmid MM, Balschi JA, Colucci WS. Decreased ATP production and myocardial contractile reserve in metabolic heart disease. J Mol Cell Cardiol 2018; 116:106-114. [PMID: 29409987 PMCID: PMC5871926 DOI: 10.1016/j.yjmcc.2018.01.017] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 01/25/2018] [Accepted: 01/30/2018] [Indexed: 01/08/2023]
Abstract
Metabolic syndrome is a cluster of obesity-related metabolic abnormalities that lead to metabolic heart disease (MHD) with left ventricular pump dysfunction. Although MHD is thought to be associated with myocardial energetic deficiency, two key questions have not been answered. First, it is not known whether there is a sufficient energy deficit to contribute to pump dysfunction. Second, the basis for the energy deficit is not clear. To address these questions, mice were fed a high fat, high sucrose (HFHS) 'Western' diet to recapitulate the MHD phenotype. In isolated beating hearts, we used 31P NMR spectroscopy with magnetization transfer to determine a) the concentrations of high energy phosphates ([ATP], [ADP], [PCr]), b) the free energy of ATP hydrolysis (∆G~ATP), c) the rate of ATP production and d) flux through the creatine kinase (CK) reaction. At the lowest workload, the diastolic pressure-volume relationship was shifted upward in HFHS hearts, indicative of diastolic dysfunction, whereas systolic function was preserved. At this workload, the rate of ATP synthesis was decreased in HFHS hearts, and was associated with decreases in both [PCr] and ∆G~ATP. Higher work demands unmasked the inability of HFHS hearts to increase systolic function and led to a further decrease in ∆G~ATP to a level that is not sufficient to maintain normal function of sarcoplasmic Ca2+-ATPase (SERCA). While [ATP] was preserved at all work demands in HFHS hearts, the progressive increase in [ADP] led to a decrease in ∆G~ATP with increased work demands. Surprisingly, CK flux, CK activity and total creatine were normal in HFHS hearts. These findings differ from dilated cardiomyopathy, in which the energetic deficiency is associated with decreases in CK flux, CK activity and total creatine. Thus, in HFHS-fed mice with MHD there is a distinct metabolic phenotype of the heart characterized by a decrease in ATP production that leads to a functionally-important energetic deficiency and an elevation of [ADP], with preservation of CK flux.
Collapse
Affiliation(s)
- Ivan Luptak
- Myocardial Biology Unit, Boston University School of Medicine, Boston, MA, United States
| | - Aaron L Sverdlov
- Myocardial Biology Unit, Boston University School of Medicine, Boston, MA, United States; Heart Failure Unit, School of Medicine and Public Health, University of Newcastle, NSW 2300, Australia
| | - Marcello Panagia
- Myocardial Biology Unit, Boston University School of Medicine, Boston, MA, United States
| | - Fuzhong Qin
- Myocardial Biology Unit, Boston University School of Medicine, Boston, MA, United States
| | - David R Pimentel
- Myocardial Biology Unit, Boston University School of Medicine, Boston, MA, United States
| | - Dominique Croteau
- Myocardial Biology Unit, Boston University School of Medicine, Boston, MA, United States
| | - Deborah A Siwik
- Myocardial Biology Unit, Boston University School of Medicine, Boston, MA, United States
| | - Joanne S Ingwall
- Physiological NMR Core Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Markus M Bachschmid
- Vascular Biology Unit, Boston University School of Medicine, Boston, MA, United States
| | - James A Balschi
- Physiological NMR Core Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Wilson S Colucci
- Myocardial Biology Unit, Boston University School of Medicine, Boston, MA, United States.
| |
Collapse
|
40
|
Abdurrachim D, Prompers JJ. Evaluation of cardiac energetics by non-invasive 31P magnetic resonance spectroscopy. Biochim Biophys Acta Mol Basis Dis 2017; 1864:1939-1948. [PMID: 29175056 DOI: 10.1016/j.bbadis.2017.11.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 11/17/2017] [Accepted: 11/18/2017] [Indexed: 01/10/2023]
Abstract
Alterations in myocardial energy metabolism have been implicated in the pathophysiology of cardiac diseases such as heart failure and diabetic cardiomyopathy. 31P magnetic resonance spectroscopy (MRS) is a powerful tool to investigate cardiac energetics non-invasively in vivo, by detecting phosphorus (31P)-containing metabolites involved in energy supply and buffering. In this article, we review the historical development of cardiac 31P MRS, the readouts used to assess cardiac energetics from 31P MRS, and how 31P MRS studies have contributed to the understanding of cardiac energy metabolism in heart failure and diabetes. This article is part of a Special issue entitled Cardiac adaptations to obesity, diabetes and insulin resistance, edited by Professors Jan F.C. Glatz, Jason R.B. Dyck and Christine Des Rosiers.
Collapse
Affiliation(s)
- Desiree Abdurrachim
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Functional Metabolism Group, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore
| | - Jeanine J Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
| |
Collapse
|
41
|
Karamat FA, Horjus DL, Haan YC, van der Woude L, Schaap MC, Oudman I, van Montfrans GA, Nieuwland R, Salomons GS, Clark JF, Brewster LM. The acute effect of beta-guanidinopropionic acid versus creatine or placebo in healthy men (ABC-Trial): A randomized controlled first-in-human trial. Br J Clin Pharmacol 2017; 83:2626-2635. [PMID: 28795416 PMCID: PMC5698587 DOI: 10.1111/bcp.13390] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 05/13/2017] [Accepted: 06/14/2017] [Indexed: 12/11/2022] Open
Abstract
Aims Increasing evidence indicates that the ATP‐generating enzyme creatine kinase (CK) is involved in hypertension. CK rapidly regenerates ATP from creatine phosphate and ADP. Recently, it has been shown that beta‐guanidinopropionic acid (GPA), a kidney‐synthesized creatine analogue and competitive CK inhibitor, reduced blood pressure in spontaneously hypertensive rats. To further develop the substance as a potential blood pressure‐lowering agent, we assessed the tolerability of a sub‐therapeutic GPA dose in healthy men. Methods In this active and placebo‐controlled, triple‐blind, single‐centre trial, we recruited 24 healthy men (18–50 years old, BMI 18.5–29.9 kg m−2) in the Netherlands. Participants were randomized (1:1:1) to one week daily oral administration of GPA 100 mg, creatine 5 g, or matching placebo. The primary outcome was the tolerability of GPA, in an intent‐to‐treat analysis. Results Twenty‐four randomized participants received the allocated intervention and 23 completed the study. One participant in the placebo arm dropped out for personal reasons. GPA was well tolerated, without serious or severe adverse events. No abnormalities were reported with GPA use in clinical safety parameters, including physical examination, laboratory studies, or 12‐Lead ECG. At day 8, mean plasma GPA was 213.88 (SE 0.07) in the GPA arm vs. 32.75 (0.00) nmol l−1 in the placebo arm, a mean difference of 181.13 (95% CI 26.53–335.72). Conclusion In this first‐in‐human trial, low‐dose GPA was safe and well‐tolerated when used during 1 week in healthy men. Subsequent studies should focus on human pharmacokinetic and pharmacodynamic assessments with different doses.
Collapse
Affiliation(s)
- Fares A Karamat
- Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Deborah L Horjus
- Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Yentl C Haan
- Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Lisa van der Woude
- Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Marianne C Schaap
- Department of Laboratory Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Inge Oudman
- Department of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Gert A van Montfrans
- Department of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Rienk Nieuwland
- Department of Laboratory Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Gajja S Salomons
- Metabolic Unit, Department of Clinical Chemistry, VU University Medical Center, Neuroscience Amsterdam, Amsterdam, The Netherlands
| | - Joseph F Clark
- Department of Social Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Lizzy M Brewster
- Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Department of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Department of Neurology, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
| |
Collapse
|
42
|
Bertero E, Prates Roma L, Ameri P, Maack C. Cardiac effects of SGLT2 inhibitors: the sodium hypothesis. Cardiovasc Res 2017; 114:12-18. [DOI: 10.1093/cvr/cvx149] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 08/02/2017] [Indexed: 12/17/2022] Open
Abstract
Abstract
The effects of intense glycaemic control on macrovascular complications in patients with type 2 diabetes are incompletely resolved, and many glucose-lowering medications negatively affect cardiovascular outcomes. Recently, the EMPA-REG OUTCOME trial revealed that empagliflozin, an inhibitor of the sodium-glucose cotransporter 2 (SGLT2), substantially reduced the risk of hospitalization for heart failure, death from cardiovascular causes, and all-cause mortality in patients with type 2 diabetes mellitus at high cardiovascular risk. Although several mechanisms may explain this benefit, plasma volume contraction and a metabolic switch favouring cardiac ketone bodies oxidation have recently been proposed as the major drivers. Recent experimental work has prompted a novel and intriguing hypothesis, according to which empagliflozin may reduce intracellular sodium (Na+) load observed in failing cardiac myocytes by inhibiting the sarcolemmal Na+/H+ exchanger. Since elevated intracellular Na+ hampers mitochondrial Ca2+ handling and thereby, deteriorates energy supply and demand matching and the mitochondrial antioxidative defence systems, empagliflozin may positively affect cardiac function by restoring mitochondrial function, and redox state in the failing heart. Here, we review the current evidence for such a third mechanistic hypothesis, which may foster heart failure and diabetes research into a new direction which harbours several potential targets for therapeutic intervention.
Collapse
Affiliation(s)
- Edoardo Bertero
- Clinic for Internal Medicine III, University of the Saarland, Homburg, Germany
- Cardiology Unit, IRCCS Policlinic Hospital San Martino & Department of Internal Medicine, University of Genova, Genova, Italy
| | - Leticia Prates Roma
- Clinic for Internal Medicine III, University of the Saarland, Homburg, Germany
| | - Pietro Ameri
- Cardiology Unit, IRCCS Policlinic Hospital San Martino & Department of Internal Medicine, University of Genova, Genova, Italy
| | - Christoph Maack
- Clinic for Internal Medicine III, University of the Saarland, Homburg, Germany
| |
Collapse
|
43
|
Peterzan MA, Lygate CA, Neubauer S, Rider OJ. Metabolic remodeling in hypertrophied and failing myocardium: a review. Am J Physiol Heart Circ Physiol 2017. [PMID: 28646030 DOI: 10.1152/ajpheart.00731.2016] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The energy starvation hypothesis proposes that maladaptive metabolic remodeling antedates, initiates, and maintains adverse contractile dysfunction in heart failure (HF). Better understanding of the cardiac metabolic phenotype and metabolic signaling could help identify the role metabolic remodeling plays within HF and the conditions known to transition toward HF, including "pathological" hypertrophy. In this review, we discuss metabolic phenotype and metabolic signaling in the contexts of pathological hypertrophy and HF. We discuss the significance of alterations in energy supply (substrate utilization, oxidative capacity, and phosphotransfer) and energy sensing using observations from human and animal disease models and models of manipulated energy supply/sensing. We aim to provide ways of thinking about metabolic remodeling that center around metabolic flexibility, capacity (reserve), and efficiency rather than around particular substrate preferences or transcriptomic profiles. We show that maladaptive metabolic remodeling takes multiple forms across multiple energy-handling domains. We suggest that lack of metabolic flexibility and reserve (substrate, oxidative, and phosphotransfer) represents a final common denominator ultimately compromising efficiency and contractile reserve in stressful contexts.
Collapse
Affiliation(s)
- Mark A Peterzan
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Craig A Lygate
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Stefan Neubauer
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Oliver J Rider
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| |
Collapse
|
44
|
Kohlhaas M, Nickel AG, Maack C. Mitochondrial energetics and calcium coupling in the heart. J Physiol 2017; 595:3753-3763. [PMID: 28105746 DOI: 10.1113/jp273609] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 12/22/2016] [Indexed: 12/21/2022] Open
Abstract
Contraction and relaxation of the heart consume large amounts of energy that need to be replenished by oxidative phosphorylation in mitochondria, and matching energy supply to demand involves the complimentary control of respiration through ADP and Ca2+ . In heart failure, an imbalance between ADP and Ca2+ leads to oxidation of mitochondrial pyridine nucleotides, where NADH oxidation may limit ATP production and contractile function, while NADPH oxidation can induce oxidative stress with consecutive maladaptive remodelling. Understanding the complex mechanisms that disturb this finely tuned equilibrium may aid the development of drugs that could ameliorate the progression of heart failure beyond the classical neuroendocrine inhibition.
Collapse
Affiliation(s)
- Michael Kohlhaas
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - Alexander G Nickel
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - Christoph Maack
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| |
Collapse
|
45
|
Booij HG, Koning AM, van Goor H, de Boer RA, Westenbrink BD. Selecting heart failure patients for metabolic interventions. Expert Rev Mol Diagn 2016; 17:141-152. [DOI: 10.1080/14737159.2017.1266939] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Harmen G. Booij
- University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Anne M. Koning
- University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Harry van Goor
- University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Rudolf A. de Boer
- University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - B. Daan Westenbrink
- University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| |
Collapse
|
46
|
Pasqualini FS, Nesmith AP, Horton RE, Sheehy SP, Parker KK. Mechanotransduction and Metabolism in Cardiomyocyte Microdomains. BIOMED RESEARCH INTERNATIONAL 2016; 2016:4081638. [PMID: 28044126 PMCID: PMC5164897 DOI: 10.1155/2016/4081638] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 11/03/2016] [Accepted: 11/07/2016] [Indexed: 01/11/2023]
Abstract
Efficient contractions of the left ventricle are ensured by the continuous transfer of adenosine triphosphate (ATP) from energy production sites, the mitochondria, to energy utilization sites, such as ionic pumps and the force-generating sarcomeres. To minimize the impact of intracellular ATP trafficking, sarcomeres and mitochondria are closely packed together and in proximity with other ultrastructures involved in excitation-contraction coupling, such as t-tubules and sarcoplasmic reticulum junctions. This complex microdomain has been referred to as the intracellular energetic unit. Here, we review the literature in support of the notion that cardiac homeostasis and disease are emergent properties of the hierarchical organization of these units. Specifically, we will focus on pathological alterations of this microdomain that result in cardiac diseases through energy imbalance and posttranslational modifications of the cytoskeletal proteins involved in mechanosensing and transduction.
Collapse
Affiliation(s)
- Francesco S. Pasqualini
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Sciences, Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA
- Institute for Regenerative Medicine (IREM), Wyss Translational Center, University and ETH Zurich, Zurich, Switzerland
| | - Alexander P. Nesmith
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Sciences, Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA
| | - Renita E. Horton
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Sciences, Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA
- James Worth Bagley College of Engineering and College of Agriculture and Life Sciences, Mississippi State University, Starkville, MS, USA
| | - Sean P. Sheehy
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Sciences, Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA
| | - Kevin Kit Parker
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Sciences, Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA
| |
Collapse
|
47
|
Creatine kinase inhibition lowers systemic arterial blood pressure in spontaneously hypertensive rats. J Hypertens 2016; 34:2418-2426. [DOI: 10.1097/hjh.0000000000001090] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
48
|
Ostojic SM, Ostojic J, Drid P, Vranes M. Guanidinoacetic acid versus creatine for improved brain and muscle creatine levels: a superiority pilot trial in healthy men. Appl Physiol Nutr Metab 2016; 41:1005-7. [DOI: 10.1139/apnm-2016-0178] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this randomized, double-blind, crossover trial, we evaluated whether 4-week supplementation with guanidinoacetic acid (GAA) is superior to creatine in facilitating creatine levels in healthy men (n = 5). GAA (3.0 g/day) resulted in a more powerful rise (up to 16.2%) in tissue creatine levels in vastus medialis muscle, middle-cerebellar peduncle, and paracentral grey matter, as compared with creatine (P < 0.05). These results indicate that GAA as a preferred alternative to creatine for improved bioenergetics in energy-demanding tissues.
Collapse
Affiliation(s)
- Sergej M. Ostojic
- Applied Bioenergetics Lab, Biomedical Sciences Department, Faculty of Sport and Physical Education, University of Novi Sad, Lovcenska 16, Novi Sad 21000, Serbia
- University of Belgrade School of Medicine, Belgrade, Serbia
| | - Jelena Ostojic
- University Clinical Center of Vojvodina, Novi Sad, Serbia
| | - Patrik Drid
- Applied Bioenergetics Lab, Biomedical Sciences Department, Faculty of Sport and Physical Education, University of Novi Sad, Lovcenska 16, Novi Sad 21000, Serbia
| | - Milan Vranes
- Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
| |
Collapse
|
49
|
Abstract
Creatine is a principle component of the creatine kinase (CK) phosphagen system common to all vertebrates. It is found in excitable cells, such as cardiomyocytes, where it plays an important role in the buffering and transport of chemical energy to ensure that supply meets the dynamic demands of the heart. Multiple components of the CK system, including intracellular creatine levels, are reduced in heart failure, while ischaemia and hypoxia represent acute crises of energy provision. Elevation of myocardial creatine levels has therefore been suggested as potentially beneficial, however, achieving this goal is not trivial. This mini-review outlines the evidence in support of creatine elevation and critically examines the pharmacological approaches that are currently available. In particular, dietary creatine-supplementation does not sufficiently elevate creatine levels in the heart due to subsequent down-regulation of the plasma membrane creatine transporter (CrT). Attempts to increase passive diffusion and bypass the CrT, e.g. via creatine esters, have yet to be tested in the heart. However, studies in mice with genetic overexpression of the CrT demonstrate proof-of-principle that elevated creatine protects the heart from ischaemia-reperfusion injury. This suggests activation of the CrT as a major unmet pharmacological target. However, translation of this finding to the clinic will require a greater understanding of CrT regulation in health and disease and the development of small molecule activators.
Collapse
Affiliation(s)
| | | | | | - Craig A Lygate
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Headington OX3 7BN, UK.
| |
Collapse
|
50
|
Metabolic compartmentation in rainbow trout cardiomyocytes: coupling of hexokinase but not creatine kinase to mitochondrial respiration. J Comp Physiol B 2016; 187:103-116. [PMID: 27522222 DOI: 10.1007/s00360-016-1025-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 07/22/2016] [Accepted: 07/29/2016] [Indexed: 01/12/2023]
Abstract
Rainbow trout (Oncorhynchus mykiss) cardiomyocytes have a simple morphology with fewer membrane structures such as sarcoplasmic reticulum and t-tubules penetrating the cytosol. Despite this, intracellular ADP diffusion is restricted. Intriguingly, although diffusion is restricted, trout cardiomyocytes seem to lack the coupling between mitochondrial creatine kinase (CK) and respiration. Our aim was to study the distribution of diffusion restrictions in permeabilized trout cardiomyocytes and verify the role of CK. We found a high activity of hexokinase (HK), which led us to reassess the situation in trout cardiomyocytes. We show that diffusion restrictions are more prominent than previously thought. In the presence of a competitive ADP-trapping system, ADP produced by HK, but not CK, was channeled to the mitochondria. In agreement with this, we found no positively charged mitochondrial CK in trout heart homogenate. The results were best fit by a simple mathematical model suggesting that trout cardiomyocytes lack a functional coupling between ATPases and pyruvate kinase. The model simulations show that diffusion is restricted to almost the same extent in the cytosol and by the outer mitochondrial membrane. Furthermore, they confirm that HK, but not CK, is functionally coupled to respiration. In perspective, our results suggest that across a range of species, cardiomyocyte morphology and metabolism go hand in hand with cardiac performance, which is adapted to the circumstances. Mitochondrial CK is coupled to respiration in adult mammalian hearts, which are specialized to high, sustained performance. HK associates with mitochondria in hearts of trout and neonatal mammals, which are more hypoxia-tolerant.
Collapse
|