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Blanchard A, Aminot M, Gould N, Léger A, Pichaud N. Flies on the rise: acclimation effect on mitochondrial oxidation capacity at normal and high temperatures in Drosophila melanogaster. J Exp Biol 2024; 227:jeb247706. [PMID: 38841909 DOI: 10.1242/jeb.247706] [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: 03/07/2024] [Accepted: 05/28/2024] [Indexed: 06/07/2024]
Abstract
Increased average temperatures and extreme thermal events (such as heatwaves) brought forth by climate change impose important constraints on aerobic metabolism. Notably, mitochondrial metabolism, which is affected by both long- and short-term temperature changes, has been put forward as an important determinant for thermal tolerance of organisms. This study examined the influence of phenotypic plasticity on metabolic and physiological parameters in Drosophila melanogaster and the link between mitochondrial function and their upper thermal limits. We showed that D. melanogaster acclimated to 15°C have a 0.65°C lower critical thermal maximum (CTmax) compared with those acclimated to 24°C. Drosophila melanogaster acclimated to 15°C exhibited a higher proportion of shorter saturated and monounsaturated fatty acids, concomitant with lower proportions of polyunsaturated fatty acids. No mitochondrial quantitative changes (fractional area and number) were detected between acclimation groups, but changes of mitochondrial oxidation capacities were observed. Specifically, in both 15°C- and 24°C-acclimated flies, complex I-induced respiration was increased when measured between 15 and 24°C, but drastically declined when measured at 40°C. When succinate and glycerol-3-phosphate were added, this decrease was however compensated for in flies acclimated to 24°C, suggesting an important impact of acclimation on mitochondrial function related to thermal tolerance. Our study reveals that the use of oxidative substrates at high temperatures is influenced by acclimation temperature and strongly related to upper thermal tolerance as a difference of 0.65°C in CTmax translates into significant mitochondrial changes.
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Affiliation(s)
- Arianne Blanchard
- New Brunswick Centre for Precision Medicine, Moncton, NB E1C8X3, Canada
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB E1A 3E9, Canada
| | - Mélanie Aminot
- New Brunswick Centre for Precision Medicine, Moncton, NB E1C8X3, Canada
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB E1A 3E9, Canada
| | - Nathalie Gould
- New Brunswick Centre for Precision Medicine, Moncton, NB E1C8X3, Canada
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB E1A 3E9, Canada
| | - Adèle Léger
- New Brunswick Centre for Precision Medicine, Moncton, NB E1C8X3, Canada
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB E1A 3E9, Canada
| | - Nicolas Pichaud
- New Brunswick Centre for Precision Medicine, Moncton, NB E1C8X3, Canada
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB E1A 3E9, Canada
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Flensted-Jensen M, Kleis-Olsen AS, Hassø RK, Lindtofte S, Corral Pérez J, Ortega-Gómez S, Larsen S. Combined changes in temperature and pH mimicking exercise result in decreased efficiency in muscle mitochondria. J Appl Physiol (1985) 2024; 136:79-88. [PMID: 37969081 DOI: 10.1152/japplphysiol.00293.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 11/07/2023] [Accepted: 11/10/2023] [Indexed: 11/17/2023] Open
Abstract
It is well known that exercise efficiency declines at intensities above the lactate threshold, yet the underlying mechanisms are poorly understood. Some have suggested it is due to a decline in mitochondrial efficiency, but this is difficult to examine in vivo. Therefore, the aim of the current study was to examine how changes in temperature and pH, mimicking those that occur during exercise, affect mitochondrial efficiency in skeletal muscle mitochondria. This study was performed on quadriceps muscle of 20 wild-type mice. Muscle tissue was dissected and either permeabilized (n = 10) or homogenized for isolation of mitochondria (n = 10), and oxidative phosphorylation capacity and P/O ratio were assessed using high-resolution respirometry. Samples from each muscle were analyzed in both normal physiological conditions (37°C, pH 7.4), decreased pH (6.8), increased temperature (40°C), and a combination of both. The combination of increased temperature and decreased pH resulted in a significantly lower P/O ratio, mirrored by an increase in leak respiration and a decrease in respiratory control ratio (RCR), in isolated mitochondria. In permeabilized fibers, RCR and leak were relatively unaffected, though a main effect of temperature was observed. Oxidative phosphorylation capacity was unaffected by changes in pH and temperature in both isolated mitochondria and permeabilized fibers. These results indicate that exercise-like changes in temperature and pH lead to impaired mitochondrial efficiency. These findings offer some degree of support to the concept of decreased mitochondrial efficiency during exercise, and may have implications for the assessment of mitochondrial function related to exercise.NEW & NOTEWORTHY To the best of our knowledge, this is the first study to examine the effects of combined changes in temperature and pH, mimicking intramuscular alterations during exercise. Our findings suggest that mitochondrial efficiency is impaired during exercise of moderate to high intensity, which could be a possible mechanism contributing to the decline in exercise efficiency at intensities above the lactate threshold.
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Affiliation(s)
- Mathias Flensted-Jensen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ann-Sofie Kleis-Olsen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rasmus Kinimond Hassø
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Søren Lindtofte
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Juan Corral Pérez
- MOVE-IT Research Group, Department of Physical Education, Faculty of Education Sciences, University of Cádiz, Cádiz, Spain
- ExPhy Research Group, Department of Physical Education, Instituto de Investigación e Innovación Biomédica de Cádiz (INiBICA), Universidad de Cádiz, Cádiz, Spain
| | - Sonia Ortega-Gómez
- MOVE-IT Research Group, Department of Physical Education, Faculty of Education Sciences, University of Cádiz, Cádiz, Spain
- Biomedical Research and Innovation Institute of Cádiz (INiBICA) Research Unit, Puerta del Mar University Hospital, Cádiz, Spain
| | - Steen Larsen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- Clinical Research Centre, Medical University of Bialystok, Bialystok, Poland
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3
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Roussel D, Janillon S, Teulier L, Pichaud N. Succinate oxidation rescues mitochondrial ATP synthesis at high temperature in Drosophila melanogaster. FEBS Lett 2023; 597:2221-2229. [PMID: 37463836 DOI: 10.1002/1873-3468.14701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/05/2023] [Accepted: 07/03/2023] [Indexed: 07/20/2023]
Abstract
Decreased NADH-induced and increased reduced FADH2 -induced respiration rates at high temperatures are associated with thermal tolerance in Drosophila. Here, we determined whether this change was associated with adjustments of adenosine triphosphate (ATP) production rate and coupling efficiency (ATP/O) in Drosophila melanogaster. We show that decreased pyruvate + malate oxidation at 35°C is associated with a collapse of ATP synthesis and a drop in ATP/O ratio. However, adding succinate triggered a full compensation of both oxygen consumption and ATP synthesis rates at this high temperature. Addition of glycerol-3-phosphate (G3P) led to a huge increase in respiration with no further advantage in terms of ATP production. We conclude that succinate is the only alternative substrate able to compensate both oxygen consumption and ATP production rates during oxidative phosphorylation at high temperature, which has important implications for thermal adaptation.
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Affiliation(s)
- Damien Roussel
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, Villeurbanne, France
| | - Sonia Janillon
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, UMR 5558 LBBE, Villeurbanne, France
| | - Loïc Teulier
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, Villeurbanne, France
| | - Nicolas Pichaud
- Department of Chemistry and Biochemistry, Université de Moncton, New Brunswick, Canada
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Singh AK, Jhalani M, Shahi SK, Christopher R, Kumar B, Das MK. Acute Encephalopathy in Children From Muzaffarpur, Bihar, India, and the Potential Role of Ambient Heat Stress-Induced Mitochondrial Dysfunction. Cureus 2023; 15:e37073. [PMID: 37153288 PMCID: PMC10156069 DOI: 10.7759/cureus.37073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2023] [Indexed: 04/05/2023] Open
Abstract
BACKGROUND Periodic outbreaks of acute encephalopathy in children have been reported from Muzaffarpur, Bihar, India. No infectious cause has been identified for this. This study presents the clinical and metabolic profile of children hospitalized with acute encephalopathy and the potential role of ambient heat stress. METHODS This cross-sectional study included children (<15 years) with acute encephalopathy admitted from April 4, 2019, to July 4, 2019. The clinical and laboratory investigations included infections, metabolic abnormalities, and muscle tissue analysis. The children who had metabolic derangements but no infectious cause were labeled as acute metabolic encephalopathy. The descriptive analysis summarized the clinical, laboratory, and histopathology findings, and their association with the ambient heat parameters was explored. RESULTS Out of the 450 children hospitalized (median age, four years), 94 (20.9%) died. Children had early morning onset (89%), seizures (99%), fever (82%), hypoglycemia at admission (64%), raised aminotransferases (60%), and high blood urea (66%). Blood lactate (50%), lactate dehydrogenase (84%), pyruvate (100%), ammonia (32%), and creatinine phosphokinase (69%) were raised. Viral marker tests were negative. The patients had abnormal metabolic markers like decreased blood-free carnitine, elevated blood acylcarnitines, and elevated urinary lactate, oxalate, maleate, adipate, and fatty acid metabolites. Blood carnitine and acylcarnitine levels normalized in 75% of the patients treated with carnitine and coenzyme-Q. Muscle tissues showed megamitochondria on electron microscopy and reduced respiratory enzyme complex-I activity. A significant correlation between the number of admissions and ambient heat indices was observed. CONCLUSIONS The findings suggest secondary mitochondrial dysfunction as a possible mechanism for acute encephalopathy in children from Muzaffarpur, Bihar, and ambient heat stress as a possible risk factor.
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Horne LM, DeVries DR, Wright R, Irwin E, Staton BA, Abdelrahman HA, Stoeckel JA. Thermal performance of the electron transport system Complex III in seven Alabama fishes. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:153-162. [PMID: 36285344 DOI: 10.1002/jez.2667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 07/13/2022] [Accepted: 09/23/2022] [Indexed: 11/06/2022]
Abstract
Management of fish populations for conservation in thermally variable systems requires an understanding of the fish's underlying physiology and responses to thermal stress. Physiological research at the organismal level provides information on the overall effects of stressors such as extreme temperature fluctuations. While experiments with whole organisms provide information as to the overall effects of temperature fluctuations, biochemical assays of thermal stress provide direct results of exposure that are both sensitive and specific. Electron transport system (ETS; Complex III) assays quantify a rate-limiting step of respiratory enzymes. Parameters that can be estimated via this approach include optimum thermal temperature (Topt ) and optimal breadth of thermal performance (Tbreadth ), which can both be related to organismal-level temperature thresholds. We exposed enzymes of seven fish species (native fish chosen to represent a typical community in Alabama streams) to temperatures in the range 11-44°C. The resultant enzymatic thermal performance curves showed that Topt , the lower temperature for enzyme optimal thermal performance (Tlow ), the upper temperature for enzyme optimal thermal performance (Tup ), and Tbreadth differed among species. Relationships between enzymatic activity and temperature for all fish followed a pattern of steadily increasing enzyme activity to Topt before gradually decreasing with increasing temperature. A comparison of our enzyme optimum and upper-temperature limit results versus published critical thermal maxima values supports that ETS Complex III assays may be useful for assessing organismal-level thermal tolerance.
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Affiliation(s)
- Lindsay M Horne
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, Alabama, USA.,Department of Biology, School of Mathematics and Sciences, Lincoln Memorial University, Tennessee, Harrogate, USA
| | - Dennis R DeVries
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, Alabama, USA
| | - Russell Wright
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, Alabama, USA
| | - Elise Irwin
- U.S. Geological Survey, Cooperative Fish and Wildlife Research Units, Auburn, Alabama, USA
| | | | - Hisham A Abdelrahman
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, Alabama, USA.,Department of Veterinary Hygiene and Management, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
| | - James A Stoeckel
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, Alabama, USA
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6
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Increased Mitochondrial Calcium Fluxes in Hypertrophic Right Ventricular Cardiomyocytes from a Rat Model of Pulmonary Artery Hypertension. Life (Basel) 2023; 13:life13020540. [PMID: 36836897 PMCID: PMC9967871 DOI: 10.3390/life13020540] [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: 12/21/2022] [Revised: 02/08/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
Pulmonary artery hypertension causes right ventricular hypertrophy which rapidly progresses to heart failure with underlying cardiac mitochondrial dysfunction. Prior to failure, there are alterations in cytosolic Ca2+ handling that might impact mitochondrial function in the compensatory phase of RV hypertrophy. Our aims, therefore, were (i) to measure beat-to-beat mitochondrial Ca2+ fluxes, and (ii) to determine mitochondrial abundance and function in non-failing, hypertrophic cardiomyocytes. Male Wistar rats were injected with either saline (CON) or monocrotaline (MCT) to induce pulmonary artery hypertension and RV hypertrophy after four weeks. Cytosolic Ca2+ ([Ca2+]cyto) transients were obtained in isolated right ventricular (RV) cardiomyocytes, and mitochondrial Ca2+ ([Ca2+]mito) was recorded in separate RV cardiomyocytes. The distribution and abundance of key proteins was determined using confocal and stimulated emission depletion (STED) microscopy. The RV mitochondrial function was also assessed in RV homogenates using oxygraphy. The MCT cardiomyocytes had increased area, larger [Ca2+]cyto transients, increased Ca2+ store content, and faster trans-sarcolemmal Ca2+ extrusion relative to CON. The MCT cardiomyocytes also had larger [Ca2+]mito transients. STED images detected increased mitochondrial protein abundance (TOM20 clusters per μm2) in MCT, yet no difference was found when comparing mitochondrial respiration and membrane potential between the groups. We suggest that the larger [Ca2+]mito transients compensate to match ATP supply to the increased energy demands of hypertrophic cardiomyocytes.
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7
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Meyer LF, Rajadhyaksha PM, Shah DK. Physiologically-based pharmacokinetic model for 2,4-dinitrophenol. J Pharmacokinet Pharmacodyn 2022; 49:325-336. [PMID: 35089483 DOI: 10.1007/s10928-022-09806-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/10/2022] [Indexed: 11/29/2022]
Abstract
New approaches in drug development are needed to address the growing epidemic of obesity as the prevalence of obesity increases worldwide. 2,4-Dinitrophenol (DNP) is an oxidative phosphorylation uncoupling agent that was widely used in the early 1930s for weight loss but was quickly banned by the FDA due to the severe toxicities associated with the compound. One of the limitations leading to the demise of DNP as a pharmaceutical was a lack of understanding about the pharmacokinetic-pharmacodynamic relationship. The purpose of this study was to investigate whole body disposition of DNP in order to understand the relationship between the pharmacokinetics, efficacy and toxicity in the C57BL/6J diet induced obese mouse model. Following intravenous administration of 1 mg/kg, and intraperitoneal administration of 5 mg/kg and 15 mg/kg of DNP, we found limited DNP distribution to tissues. Experimentally measured partition coefficients were found to be less than 1 for all analyzed tissues. In addition, DNP exhibits significant nonlinear pharmacokinetics, which we have attributed to nonlinear plasma protein binding and nonlinear partitioning into liver and kidney. By enhancing our understanding of the PK-PD relationship, we can develop new approaches to leverage oxidative phosphorylation uncoupling as a weight loss strategy.
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Affiliation(s)
- Lyndsey F Meyer
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, The State University of New York at Buffalo, 455 Pharmacy Building, Buffalo, NY, 14214-8033, USA
| | - Pooja M Rajadhyaksha
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, The State University of New York at Buffalo, 455 Pharmacy Building, Buffalo, NY, 14214-8033, USA
| | - Dhaval K Shah
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, The State University of New York at Buffalo, 455 Pharmacy Building, Buffalo, NY, 14214-8033, USA.
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8
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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.
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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
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9
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Thermally tolerant intertidal triplefin fish (Tripterygiidae) sustain ATP dynamics better than subtidal species under acute heat stress. Sci Rep 2021; 11:11074. [PMID: 34040122 PMCID: PMC8155050 DOI: 10.1038/s41598-021-90575-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 04/30/2021] [Indexed: 11/18/2022] Open
Abstract
Temperature is a key factor that affects all levels of organization. Minute shifts away from thermal optima result in detrimental effects that impact growth, reproduction and survival. Metabolic rates of ectotherms are especially sensitive to temperature and for organisms exposed to high acute temperature changes, in particular intertidal species, energetic processes are often negatively impacted. Previous investigations exploring acute heat stress have implicated cardiac mitochondrial function in determining thermal tolerance. The brain, however, is by weight, one of the most metabolically active and arguably the most temperature sensitive organ. It is essentially aerobic and entirely reliant on oxidative phosphorylation to meet energetic demands, and as temperatures rise, mitochondria become less efficient at synthesising the amount of ATP required to meet the increasing demands. This leads to an energetic crisis. Here we used brain homogenate of three closely related triplefin fish species (Bellapiscis medius, Forsterygion lapillum, and Forsterygion varium) and measured respiration and ATP dynamics at three temperatures (15, 25 and 30 °C). We found that the intertidal B. medius and F. lapillum were able to maintain rates of ATP production above rates of ATP hydrolysis at high temperatures, compared to the subtidal F. varium, which showed no difference in rates at 30 °C. These results showed that brain mitochondria became less efficient at temperatures below their respective species thermal limits, and that energetic surplus of ATP synthesis over hydrolysis narrows. In subtidal species synthesis matches hydrolysis, leaving no scope to elevate ATP supply.
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Zou R, Tao J, Qiu J, Shi W, Zou M, Chen W, Li W, Zhou N, Wang S, Ma L, Chen X. Ndufs1 Deficiency Aggravates the Mitochondrial Membrane Potential Dysfunction in Pressure Overload-Induced Myocardial Hypertrophy. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:5545261. [PMID: 33763166 PMCID: PMC7952157 DOI: 10.1155/2021/5545261] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 02/03/2021] [Accepted: 02/18/2021] [Indexed: 12/11/2022]
Abstract
Mitochondrial dysfunction has been suggested to be the key factor in the development and progression of cardiac hypertrophy. The onset of mitochondrial dysfunction and the mechanisms underlying the development of cardiac hypertrophy (CH) are incompletely understood. The present study is based on the use of multiple bioinformatics analyses for the organization and analysis of scRNA-seq and microarray datasets from a transverse aortic constriction (TAC) model to examine the potential role of mitochondrial dysfunction in the pathophysiology of CH. The results showed that NADH:ubiquinone oxidoreductase core subunit S1- (Ndufs1-) dependent mitochondrial dysfunction plays a key role in pressure overload-induced CH. Furthermore, in vivo animal studies using a TAC mouse model of CH showed that Ndufs1 expression was significantly downregulated in hypertrophic heart tissue compared to that in normal controls. In an in vitro model of angiotensin II- (Ang II-) induced cardiomyocyte hypertrophy, Ang II treatment significantly downregulated the expression of Ndufs1 in cardiomyocytes. In vitro mechanistic studies showed that Ndufs1 knockdown induced CH; decreased the mitochondrial DNA content, mitochondrial membrane potential (MMP), and mitochondrial mass; and increased the production of mitochondrial reactive oxygen species (ROS) in cardiomyocytes. On the other hand, Ang II treatment upregulated the expression levels of atrial natriuretic peptide, brain natriuretic peptide, and myosin heavy chain beta; decreased the mitochondrial DNA content, MMP, and mitochondrial mass; and increased mitochondrial ROS production in cardiomyocytes. The Ang II-mediated effects were significantly attenuated by overexpression of Ndufs1 in rat cardiomyocytes. In conclusion, our results demonstrate downregulation of Ndufs1 in hypertrophic heart tissue, and the results of mechanistic studies suggest that Ndufs1 deficiency may cause mitochondrial dysfunction in cardiomyocytes, which may be associated with the development and progression of CH.
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Affiliation(s)
- Rongjun Zou
- Heart Center, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Jun Tao
- Department of Cardiovascular Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, China
| | - Junxiong Qiu
- Department of Cardiovascular Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, China
| | - Wanting Shi
- Department of Paediatrics, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Minghui Zou
- Heart Center, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Weidan Chen
- Heart Center, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Wenlei Li
- Heart Center, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Na Zhou
- Heart Center, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Shaoli Wang
- Department of Surgical Nursing, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Li Ma
- Heart Center, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Xinxin Chen
- Heart Center, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
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11
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Roussel D, Voituron Y. Mitochondrial Costs of Being Hot: Effects of Acute Thermal Change on Liver Bioenergetics in Toads ( Bufo bufo). Front Physiol 2020; 11:153. [PMID: 32218742 PMCID: PMC7078649 DOI: 10.3389/fphys.2020.00153] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 02/12/2020] [Indexed: 01/21/2023] Open
Abstract
Global climatic warming is predicted to drive extreme thermal events, especially in temperate terrestrial environments. Hence, describing how physiological parameters are affected by acute temperature changes would allow us to understand the energy management of organisms facing such non-predictable and constraining events. As mitochondria play a key role in the conversion of energy from food into ATP but also produce harmful reactive oxygen species, the understanding of its functioning is crucial to determine the proximal causes of potential decline in an animal's performance. Here we studied the effects of acute temperature changes (between 20 and 30°C) on mitochondrial respiration, ATP synthesis rate, oxidative phosphorylation efficiency (ATP/O), and H2O2 generation in isolated liver mitochondria of a terrestrial ectotherm, the common toad (Bufo bufo). Using succinate as the respiratory substrate, we found that the mitochondrial rates of oxygen consumption, ATP synthesis, and H2O2 generation increased as the temperature increased, being 65, 52, and 66% higher at 30°C than at 20°C, respectively. We also found that the mitochondrial coupling efficiency (ATP/O) decreased, while the oxidative cost of ATP production (H2O2/ATP ratio) increased. The present results further indicate that between 40 and 60% of temperature effects on mitochondrial ATP production and H2O2 generation was at minima driven by an action on the oxidative capacity of the mitochondria. These results suggest that B. bufo may need to allocate extra energy to maintain ATP production and protect cells from oxidative stress, reducing the energy allocable performances.
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Affiliation(s)
- Damien Roussel
- CNRS, UMR 5023, Laboratoire d’Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Claude Bernard Lyon 1, Lyon, France
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12
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Fiorenza M, Lemminger AK, Marker M, Eibye K, Iaia FM, Bangsbo J, Hostrup M. High-intensity exercise training enhances mitochondrial oxidative phosphorylation efficiency in a temperature-dependent manner in human skeletal muscle: implications for exercise performance. FASEB J 2019; 33:8976-8989. [PMID: 31136218 DOI: 10.1096/fj.201900106rrr] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The purpose of the present study was to investigate whether exercise training-induced adaptations in human skeletal muscle mitochondrial bioenergetics are magnified under thermal conditions resembling sustained intense contractile activity and whether training-induced changes in mitochondrial oxidative phosphorylation (OXPHOS) efficiency influence exercise efficiency. Twenty healthy men performed 6 wk of high-intensity exercise training [i.e., speed endurance training (SET; n = 10)], or maintained their usual lifestyle (n = 10). Before and after the intervention, mitochondrial respiratory function was determined ex vivo in permeabilized muscle fibers under experimentally-induced normothermia (35°C) and hyperthermia (40°C) mimicking in vivo muscle temperature at rest and during intense exercise, respectively. In addition, activity and content of muscle mitochondrial enzymes and proteins were quantified. Exercising muscle efficiency was determined in vivo by measurements of leg hemodynamics and blood parameters during one-legged knee-extensor exercise. SET enhanced maximal OXPHOS capacity and OXPHOS efficiency at 40°C, but not at 35°C, and attenuated hyperthermia-induced decline in OXPHOS efficiency. Furthermore, SET increased expression of markers of mitochondrial content and up-regulated content of MFN2, DRP1, and ANT1. Also, SET improved exercise efficiency and capacity. These findings indicate that muscle mitochondrial bioenergetics adapts to high-intensity exercise training in a temperature-dependent manner and that enhancements in mitochondrial OXPHOS efficiency may contribute to improving exercise performance.-Fiorenza, M., Lemminger, A. K., Marker, M., Eibye, K., Iaia, F. M., Bangsbo, J., Hostrup, M. High-intensity exercise training enhances mitochondrial oxidative phosphorylation efficiency in a temperature-dependent manner in human skeletal muscle: implications for exercise performance.
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Affiliation(s)
- Matteo Fiorenza
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark.,Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Anders K Lemminger
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Mathias Marker
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Kasper Eibye
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - F Marcello Iaia
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
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13
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Obata K, Takeshita D, Morita H, Takaki M. Left ventricular mechanoenergetics in excised, cross-circulated rat hearts under hypo-, normo-, and hyperthermic conditions. Sci Rep 2018; 8:16246. [PMID: 30390094 PMCID: PMC6214925 DOI: 10.1038/s41598-018-34666-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 10/22/2018] [Indexed: 11/27/2022] Open
Abstract
We investigated the effects of altering cardiac temperature on left ventricular (LV) myocardial mechanical work and energetics using the excised, cross-circulated rat heart model. We analyzed the LV end-systolic pressure-volume relationship (ESPVR) and linear relationship between myocardial oxygen consumption per beat (VO2) and systolic pressure-volume area (PVA; total mechanical energy per beat) in isovolumically contracting rat hearts during hypo- (32 °C), normo- (37 °C), and hyperthermia (42 °C) under a 300-beats per minute pacing. LV ESPVR shifted downward with increasing cardiac temperature. The VO2-PVA relationship was superimposable in these different thermal conditions; however, each data point of VO2-PVA shifted left-downward during increasing cardiac temperature on the superimposable VO2-PVA relationship line. VO2 for Ca2+ handling in excitation-contraction coupling decreased, which was associated with increasing cardiac temperature, during which sarcoplasmic reticulum Ca2+-ATPase (SERCA) activity was suppressed, due to phospholamban phosphorylation inhibition, and instead, O2 consumption for basal metabolism was increased. The O2 cost of LV contractility for Ca2+ also increased with increasing cardiac temperature. Logistic time constants evaluating LV relaxation time were significantly shortened with increasing cardiac temperature related to the acceleration of the detachment in cross-bridge (CB) cycling, indicating increased myosin ATPase activity. The results suggested that increasing cardiac temperature induced a negative inotropic action related to SERCA activity suppression in Ca2+ handling and increased myosin ATPase activity in CB cycling. We concluded that thermal intervention could modulate cardiac inotropism by changing CB cycling, Ca2+ handling, and basal metabolism in rat hearts.
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Affiliation(s)
- Koji Obata
- Department of Physiology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan.
| | - Daisuke Takeshita
- Department of Artificial Organs, National Cerebral and Cardiovascular Center Research Institute, Suita, 565-8565, Japan
| | - Hironobu Morita
- Department of Physiology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan
| | - Miyako Takaki
- Department of Physiology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan
- Department of Orthopaedic Surgery, Nara Medical University, School of Medicine, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
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14
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Treberg JR, Braun K, Zacharias P, Kroeker K. Multidimensional mitochondrial energetics: Application to the study of electron leak and hydrogen peroxide metabolism. Comp Biochem Physiol B Biochem Mol Biol 2018; 224:121-128. [DOI: 10.1016/j.cbpb.2017.12.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 12/11/2017] [Accepted: 12/13/2017] [Indexed: 10/18/2022]
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15
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Loiselle DS, Han JC, Goo E, Chapman B, Barclay CJ, Hickey AJR, Taberner AJ. Thermodynamic analysis questions claims of improved cardiac efficiency by dietary fish oil. J Gen Physiol 2017; 148:183-93. [PMID: 27574288 PMCID: PMC5004337 DOI: 10.1085/jgp.201611620] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 08/09/2016] [Indexed: 11/25/2022] Open
Abstract
Studies in the literature describe the ability of dietary supplementation by omega-3 fish oil to increase the pumping efficiency of the left ventricle. Here we attempt to reconcile such studies with our own null results. We undertake a quantitative analysis of the improvement that could be expected theoretically, subject to physiological constraints, by posing the following question: By how much could efficiency be expected to increase if inefficiencies could be eliminated? Our approach utilizes thermodynamic analyses to investigate the contributions, both singly and collectively, of the major components of cardiac energetics to total cardiac efficiency. We conclude that it is unlikely that fish oils could achieve the required diminution of inefficiencies without greatly compromising cardiac performance.
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Affiliation(s)
- Denis S Loiselle
- Department of Physiology, The University of Auckland, Auckland 1142, New Zealand Auckland Bioengineering Institute, The University of Auckland, Auckland 1142, New Zealand
| | - June-Chiew Han
- Auckland Bioengineering Institute, The University of Auckland, Auckland 1142, New Zealand
| | - Eden Goo
- Doctor of Medicine Programme, The University of Western Australia, Crawley, Perth, Western Australia 6009, Australia
| | - Brian Chapman
- School of Applied and Biomedical Science, Faculty of Science and Technology, Federation University Australia, Churchill, Victoria 3842, Australia
| | - Christopher J Barclay
- School of Physiotherapy and Exercise Science, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Anthony J R Hickey
- School of Biological Sciences, The University of Auckland, Auckland 1142, New Zealand
| | - Andrew J Taberner
- Auckland Bioengineering Institute, The University of Auckland, Auckland 1142, New Zealand Department of Engineering Science, The University of Auckland, Auckland 1142, New Zealand
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16
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Masson SWC, Hedges CP, Devaux JBL, James CS, Hickey AJR. Mitochondrial glycerol 3-phosphate facilitates bumblebee pre-flight thermogenesis. Sci Rep 2017; 7:13107. [PMID: 29026172 PMCID: PMC5638826 DOI: 10.1038/s41598-017-13454-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 09/22/2017] [Indexed: 11/27/2022] Open
Abstract
Bumblebees (Bombus terrestris) fly at low ambient temperatures where other insects cannot, and to do so they must pre-warm their flight muscles. While some have proposed mechanisms, none fully explain how pre-flight thermogenesis occurs. Here, we present a novel hypothesis based on the less studied mitochondrial glycerol 3-phosphate dehydrogenase pathway (mGPDH). Using calorimetry, and high resolution respirometry coupled with fluorimetry, we report substrate oxidation by mGPDH in permeabilised flight muscles operates, in vitro, at a high flux, even in the absence of ADP. This may be facilitated by an endogenous, mGPDH-mediated uncoupling of mitochondria. This uncoupling increases ETS activity, which results in increased heat release. Furthermore, passive regulation of this mechanism is achieved via dampened temperature sensitivity of mGPDH relative to other respiratory pathways, and subsequent consumption of its substrate, glycerol 3-phosphate (G3P), at low temperatures. Mitochondrial GPDH may therefore facilitate pre-flight thermogenesis through poor mitochondrial coupling. We calculate this can occur at a sufficient rate to warm flight muscles until shivering commences, and until flight muscle function is adequate for bumblebees to fly in the cold.
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Affiliation(s)
- Stewart W C Masson
- School of Biological Sciences, University of Auckland, 3a Symonds St, Auckland, 1010, New Zealand
| | - Christopher P Hedges
- School of Biological Sciences, University of Auckland, 3a Symonds St, Auckland, 1010, New Zealand
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, VIC, Australia
| | - Jules B L Devaux
- School of Biological Sciences, University of Auckland, 3a Symonds St, Auckland, 1010, New Zealand
| | - Crystal S James
- School of Biological Sciences, University of Auckland, 3a Symonds St, Auckland, 1010, New Zealand
| | - Anthony J R Hickey
- School of Biological Sciences, University of Auckland, 3a Symonds St, Auckland, 1010, New Zealand.
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17
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Sampson M, Lathen DR, Dallon BW, Draney C, Ray JD, Kener KB, Parker BA, Gibbs JL, Gropp JS, Tessem JS, Bikman BT. β-Hydroxybutyrate improves β-cell mitochondrial function and survival. JOURNAL OF INSULIN RESISTANCE 2017. [DOI: 10.4102/jir.v2i1.25] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Pharmacological interventions aimed at improving outcomes in type 2 diabetes and achieving normoglycaemia, including insulin therapy, are increasingly common, despite the potential for substantial side effects. Carbohydrate-restricted diets that result in increased ketogenesis have effectively been used to improve insulin resistance, a fundamental feature of type 2 diabetes. In addition, limited evidence suggests that states of ketogenesis may also improve β-cell function in type 2 diabetics. Considering how little is known regarding the effects of ketones on β-cell function, we sought to determine the specific effects of β-Hydroxybutyrate (βHB) on pancreatic β-cell physiology and mitochondrial function. βHB treatment increased β-cell survival and proliferation, while also increasing mitochondrial mass, respiration and adenosine triphosphate (ATP) production. Despite these improvements, were unable to detect an increase in β-cell or islet insulin production and secretion. Collectively, these findings have two implications. Firstly, they indicate that β-cells have improved survival and proliferation in the midst of βHB, the circulating form of ketones. Secondly, insulin secretion does not appear to be directly related to apparent improvements in mitochondrial function and cellular proliferation.
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18
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A Model of Exposure to Extreme Environmental Heat Uncovers the Human Transcriptome to Heat Stress. Sci Rep 2017; 7:9429. [PMID: 28842615 PMCID: PMC5573409 DOI: 10.1038/s41598-017-09819-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 07/31/2017] [Indexed: 12/20/2022] Open
Abstract
The molecular mechanisms by which individuals subjected to environmental heat stress either recover or develop heat-related complications are not well understood. We analysed the changes in blood mononuclear gene expression patterns in human volunteers exposed to extreme heat in a sauna (temperature of 75.7 ± 0.86 °C). Our analysis reveals that expression changes occur rapidly with no significant increase in core temperature and continue to amplify one hour after the end of heat stress. The reprogramed transcriptome was predominantly inhibitory, as more than two-thirds of the expressed genes were suppressed. The differentially expressed genes encoded proteins that function in stress-associated pathways; including proteostasis, energy metabolism, cell growth and proliferation, and cell death, and survival. The transcriptome also included mitochondrial dysfunction, altered protein synthesis, and reduced expression of genes -related to immune function. The findings reveal the human transcriptomic response to heat and highlight changes that might underlie the health outcomes observed during heat waves.
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Napa K, Baeder AC, Witt JE, Rayburn ST, Miller MG, Dallon BW, Gibbs JL, Wilcox SH, Winden DR, Smith JH, Reynolds PR, Bikman BT. LPS from P. gingivalis Negatively Alters Gingival Cell Mitochondrial Bioenergetics. Int J Dent 2017; 2017:2697210. [PMID: 28592970 PMCID: PMC5448046 DOI: 10.1155/2017/2697210] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 02/13/2017] [Accepted: 03/20/2017] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE Oral inflammatory pathologies are linked to increased oxidative stress, thereby partly explaining their relevance in the etiology of systemic disorders. The purpose of this work was to determine the degree to which LPS from Porphyromonas gingivalis, the primary pathogen related to oral inflammation, altered gingival mitochondrial function and reactive oxygen species generation. METHODS Human gingival fibroblast (HGF-1) cells were treated with lipopolysaccharide of P. gingivalis. Mitochondrial function was determined via high-resolution respirometry. P GINGIVALIS Mitochondrial function was determined via high-resolution respirometry. RESULTS LPS-treated HGF-1 cells had significantly higher mitochondrial complex IV and higher rates of mitochondrial respiration. However, this failed to translate into greater ATP production, as ATP production was paradoxically diminished with LPS treatment. Nevertheless, production of the reactive H2O2 was elevated with LPS treatment. CONCLUSIONS LPS elicits an increase in gingival cell mitochondria content, with a subsequent increase in reactive oxygen species production (i.e., H2O2), despite a paradoxical reduction in ATP generation. These findings provide an insight into the nature of oxidative stress in oral inflammatory pathologies.
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Affiliation(s)
- Kiran Napa
- College of Dental Medicine, Roseman University of Health Sciences, South Jordan, UT, USA
| | - Andrea C. Baeder
- College of Dental Medicine, Roseman University of Health Sciences, South Jordan, UT, USA
| | - Jeffrey E. Witt
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA
| | - Sarah T. Rayburn
- College of Dental Medicine, Roseman University of Health Sciences, South Jordan, UT, USA
| | - Madison G. Miller
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA
| | - Blake W. Dallon
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA
| | - Jonathan L. Gibbs
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA
| | - Shalene H. Wilcox
- College of Dental Medicine, Roseman University of Health Sciences, South Jordan, UT, USA
| | - Duane R. Winden
- College of Dental Medicine, Roseman University of Health Sciences, South Jordan, UT, USA
| | - Jared H. Smith
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA
| | - Paul R. Reynolds
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA
| | - Benjamin T. Bikman
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA
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20
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Žūkienė R, Naučienė Z, Šilkūnienė G, Vanagas T, Gulbinas A, Zimkus A, Mildažienė V. Contribution of mitochondria to injury of hepatocytes and liver tissue by hyperthermia. MEDICINA-LITHUANIA 2017; 53:40-49. [PMID: 28256298 DOI: 10.1016/j.medici.2017.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/15/2016] [Accepted: 01/02/2017] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The aim of this study was to investigate functional changes of liver mitochondria within the experimentally modeled transition zone of radiofrequency ablation and to estimate possible contribution of these changes to the energy status of liver cells and the whole tissue. MATERIALS AND METHODS Experiments were carried out on mitochondria isolated from the perfused liver and isolated hepatocytes of male Wistar rats. Hyperthermia was induced by changing the temperature of perfusion medium in the range characteristic for the transition zone (38-52°C). After 15-min perfusion, mitochondria were isolated to investigate changes in the respiration rates and the membrane potential. Adenine nucleotides extracted from isolated hepatocytes and perfused liver subjected to hyperthermic treatment were analyzed by HPLC. RESULTS Hyperthermic liver perfusion at 42-52°C progressively impaired oxidative phosphorylation in isolated mitochondria. Significant inhibition of the respiratory chain components was observed after perfusion at 42°C, irreversible uncoupling became evident after liver perfusion at higher temperatures (46°C and above). After perfusion at 50-52°C energy supplying function of mitochondria was entirely compromised, and mitochondria turned to energy consumers. Hyperthermia-induced changes in mitochondrial function correlated well with changes in the energy status and viability of isolated hepatocytes, but not with the changes in the energy status of the whole liver tissue. CONCLUSIONS In this study the pattern of the adverse changes in mitochondrial functions that are progressing with increase in liver perfusion temperature was established. Results of experiments on isolated mitochondria and isolated hepatocytes indicate that hyperthermic treatment significantly and irreversibly inhibits energy-supplying function of mitochondria under conditions similar to those existing in the radiofrequency ablation transition zone and these changes can lead to death of hepatocytes. However, it was not possible to estimate contribution of mitochondrial injury to liver tissue energy status by estimating only hyperthermia-induced changes in adenine nucleotide amounts on the whole tissue level.
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Affiliation(s)
- Rasa Žūkienė
- Faculty of Natural Sciences, Vytautas Magnus University, Kaunas, Lithuania
| | - Zita Naučienė
- Faculty of Natural Sciences, Vytautas Magnus University, Kaunas, Lithuania
| | - Giedrė Šilkūnienė
- Faculty of Natural Sciences, Vytautas Magnus University, Kaunas, Lithuania
| | - Tomas Vanagas
- Department of Surgery, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Antanas Gulbinas
- Institute for Digestive Research, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Aurelijus Zimkus
- Institute of Biosciences, Vilnius University Life Sciences Center, Vilnius, Lithuania
| | - Vida Mildažienė
- Faculty of Natural Sciences, Vytautas Magnus University, Kaunas, Lithuania.
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21
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Deoxycholic Acid Could Induce Apoptosis and Trigger Gastric Carcinogenesis on Gastric Epithelial Cells by Quantitative Proteomic Analysis. Gastroenterol Res Pract 2016; 2016:9638963. [PMID: 28070185 PMCID: PMC5192292 DOI: 10.1155/2016/9638963] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/10/2016] [Accepted: 10/23/2016] [Indexed: 01/26/2023] Open
Abstract
Background. Pathologic duodenogastric reflux can induce or aggravate gastritis because of the presence of bile acids. Bile reflux has been generally considered to be associated with intestinal metaplasia and gastric cancer. However, the pathogenic mechanisms of the effects of bile acids on gastric mucosa are still unknown. Methods. To explore the mechanisms by which bile acids induce gastric mucosal lesions, we examined cell apoptosis in the gastric epithelial cell line GES-1 and investigated the changes in protein profiles of GES-1 cells in response to a bile acid deoxycholic acid using a proteomics approach. Changes in the profiles of the differently expressed proteins were analyzed using the DAVID and STRING programs. Results. We found apoptosis was significantly induced in GES-1 cells by deoxycholic acid. Using liquid chromatographic/tandem mass spectrometric (LC-MS/MS) methods, 134 upregulated proteins and 214 downregulated proteins were identified in the bile acid treated GES-1 cells. Bioinformatics analysis revealed the interactions and signaling networks of these differentially expressed proteins. Conclusion. These findings may improve the understanding of the molecular mechanisms underlying the pathogenicity of bile acids on gastric mucosa.
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Vostarek F, Svatunkova J, Sedmera D. Acute temperature effects on function of the chick embryonic heart. Acta Physiol (Oxf) 2016; 217:276-86. [PMID: 27083765 DOI: 10.1111/apha.12691] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 01/22/2016] [Accepted: 04/12/2016] [Indexed: 12/01/2022]
Abstract
AIM We analysed the effects of acute temperature change on the beating rate, conduction properties and calcium transients in the chick embryonic heart in vitro and in ovo. METHODS The effects of temperature change (34, 37 and 40 °C) on calcium dynamics in isolated ED4 chick hearts in vitro were investigated by high-speed calcium optical imaging. For comparison and validation of in vitro measurements, experiments were also performed in ovo using videomicroscopy. Artificial stimulation experiments were performed in vitro and in ovo to uncover conduction limits of heart segments. RESULTS Decrease in temperature from 37 to 34 °C in vitro led to a 22% drop in heart rate and unchanged amplitude of Ca(2+) transients, compared to a 25% heart rate decrease in ovo. Increase in temperature from 37 to 40 °C in vitro and in ovo led to 20 and 23% increases in heart rate, respectively, and a significant decrease in amplitude of Ca(2+) transients (atrium -35%, ventricle -38%). We observed a wide spectrum of arrhythmias in vitro, of which the most common was atrioventricular (AV) block (57%). There was variability of AV block locations. Pacing experiments in vitro and in ovo suggested that the AV blocks were likely caused by relative tissue hypoxia and not by the tachycardia itself. CONCLUSION The pacemaker and AV canal are the most temperature-sensitive segments of the embryonic heart. We suggest that the critical point for conduction is the connection of the ventricular trabecular network to the AV canal.
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Affiliation(s)
- F. Vostarek
- Czech Academy of Sciences; Institute of Physiology; Prague Czech Republic
- Faculty of Science; Charles University; Prague Czech Republic
| | - J. Svatunkova
- Czech Academy of Sciences; Institute of Physiology; Prague Czech Republic
| | - D. Sedmera
- Czech Academy of Sciences; Institute of Physiology; Prague Czech Republic
- First Faculty of Medicine; Institute of Anatomy; Charles University; Prague Czech Republic
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Power ASC, Pham T, Loiselle DS, Crossman DH, Ward ML, Hickey AJ. Impaired ADP channeling to mitochondria and elevated reactive oxygen species in hypertensive hearts. Am J Physiol Heart Circ Physiol 2016; 310:H1649-57. [DOI: 10.1152/ajpheart.00050.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 04/12/2016] [Indexed: 01/20/2023]
Abstract
Systemic hypertension initially promotes a compensatory cardiac hypertrophy, yet it progresses to heart failure (HF), and energetic deficits appear to be central to this failure. However, the transfer of energy between the mitochondria and the myofibrils is not often considered as part of the energetic equation. We compared hearts from old spontaneously hypertensive rats (SHRs) and normotensive Wistar controls. SHR hearts showed a 35% depression in mitochondrial function, yet produced at least double the amount of reactive oxygen species (ROS) in all respiration states in left ventricular (LV) homogenates. To test the connectivity between mitochondria and myofibrils, respiration was further tested in situ with LV permeabilized fibers by addition of multiple substrates and ATP, which requires hydrolysis to mediate oxidative phosphorylation. By trapping ADP using a pyruvate kinase enzyme system, we tested ADP channeling towards mitochondria, and this suppressed respiration and elevated ROS production more in the SHR fibers. The ADP-trapped state was also less relieved on creatine addition, likely reflecting the 30% depression in total CK activity in the SHR heart fibers. Confocal imaging identified a 34% longer distance between the centers of myofibril to mitochondria in the SHR hearts, which increases transverse metabolite diffusion distances (e.g., for ATP, ADP, and creatine phosphate). We propose that impaired connectivity between mitochondria and myofibrils may contribute to elevated ROS production. Impaired energy exchange could be the result of ultrastructural changes that occur with hypertrophy in this model of hypertension.
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Affiliation(s)
- Amelia S. C. Power
- School of Biological Sciences, Faculty of Science, The University of Auckland, Auckland, New Zealand; and
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Toan Pham
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Denis S. Loiselle
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand; and
| | - David H. Crossman
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Marie-Louise Ward
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Anthony J. Hickey
- School of Biological Sciences, Faculty of Science, The University of Auckland, Auckland, New Zealand; and
- Maurice Wilkins Centre, The University of Auckland, Auckland, New Zealand
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Baldi S, Pinna GD, Bruschi C, Caldara F, Maestri R, Dacosto E, Rezzani A, Popovich E, Bellinzona E, Crotti P, Montemartini S, Fracchia C. Medicinal clays improve the endurance of loaded inspiratory muscles in COPD: a randomized clinical trial of nonpharmacological treatment. Int J Chron Obstruct Pulmon Dis 2015; 10:2235-48. [PMID: 26604728 PMCID: PMC4629956 DOI: 10.2147/copd.s87999] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Inspiratory resistive breathing (IRB) challenges affect respiratory muscle endurance in healthy individuals, which is considered to be an interleukin 6 (IL-6)-dependent mechanism. Whether nonpharmacological thermal therapies promote the endurance of loaded inspiratory muscles in chronic obstructive pulmonary disease (COPD) is unclear. The objectives of this study were to compare the effects of two thermal interventions on endurance time (ET) and plasma IL-6 concentration following an IRB challenge. METHODS This study was a randomized, parallel-group, unblinded clinical trial in a single-center setting. Forty-two patients (aged 42-76 years) suffering from mild to severe COPD participated in this study. Both groups completed 12 sessions of the mud bath therapy (MBT) (n=22) or leisure thermal activity (LTA) (n=19) in a thermal spa center in Italy. Pre- and postintervention spirometry, maximum inspiratory pressure, and plasma mediators were obtained and ET and endurance oxygen expenditure (VO2Endur) were measured following IRB challenge at 40% of maximum inspiratory pressure. RESULTS There was no difference in ΔIL-6 between the intervention groups. But, IRB challenge increased cytokine IL-6 plasma levels systematically. The effect size was small. A statistically significant treatment by IRB challenge effect existed in ET, which significantly increased in the MBT group (P=0.003). In analysis of covariance treatment by IRB challenge analysis with LnVO2Endur as the dependent variable, ΔIL-6 after intervention predicted LnVO2Endur in the MBT group, but not in the LTA group. Adverse events occurred in two individuals in the MBT group, but they were mainly transient. One patient in the LTA group dropped out. CONCLUSION MBT model improves ET upon a moderate IRB challenge, indicating the occurrence of a training effect. The LnVO2Endur/ΔIL-6 suggests a physiologic adaptive mechanism in respiratory muscles of COPD patients allocated to treatment. Both thermal interventions are safe.
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Affiliation(s)
- Simonetta Baldi
- Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia)
| | - Gian Domenico Pinna
- Department of Biomedical Engineering, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia), AbanoTerme, Padua, Italy
| | - Claudio Bruschi
- Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia)
| | - Fabrizio Caldara
- Center of Thermal Studies Pietro d’Abano, AbanoTerme, Padua, Italy
| | - Roberto Maestri
- Department of Biomedical Engineering, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia), AbanoTerme, Padua, Italy
| | - Elena Dacosto
- Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia)
| | - Antonella Rezzani
- Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia)
| | - Ermanno Popovich
- Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia)
| | - Ezio Bellinzona
- Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia)
| | - Paola Crotti
- Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia)
| | - Silvia Montemartini
- Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia)
| | - Claudio Fracchia
- Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia)
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