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Takemura A, Matsunaga Y, Shinya T, Matta H. Differential Mitochondrial Adaptation of the Slow and Fast Skeletal Muscles by Endurance Running Exercise in Streptozotocin-Induced Diabetic Mice. Physiol Res 2024; 73:369-379. [PMID: 39027954 PMCID: PMC11299777 DOI: 10.33549/physiolres.935183] [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: 07/03/2023] [Accepted: 02/01/2024] [Indexed: 07/27/2024] Open
Abstract
The skeletal muscle is the main organ responsible for insulin action, and glucose disposal and metabolism. Endurance and/or resistance training raises the number of mitochondria in diabetic muscles. The details of these adaptations, including mitochondrial adaptations of the slow and fast muscles in diabetes, are unclear. This study aimed to determine whether exercise training in streptozotocin (STZ)-induced mice leads to differential adaptations in the slow and fast muscles, and improving glucose clearance. Eight-week-old mice were randomly distributed into normal control (CON), diabetes (DM), and diabetes and exercise (DM+Ex) groups. In the DM and DM+Ex groups, mice received a freshly prepared STZ (100 mg/kg) intraperitoneal injection on two consecutive days. Two weeks after the injection, the mice in the groups ran on a treadmill for 60 min at 20 m/min for a week and subsequently at 25 m/min for 5 weeks (5 days/week). The analyses indicated that running training at low speed (25 m/min) enhanced mitochondrial enzyme activity and expression of lactate and glucose transporters in the plantaris (low-oxidative) muscle that improved whole-body glucose metabolism in STZ-induced diabetic mice. There were no differences in glucose transporter expression levels in the soleus (high-oxidative) muscle. The endurance running exercise at 20-25 m/min was sufficient to induce mitochondrial adaptation in the low-oxidative muscles, but not in the high-oxidative muscles, of diabetic mice. In conclusion, the present study indicated that running training at 25 m/min improved glucose metabolism by increasing the mitochondrial enzyme activity and glucose transporter 4 and monocarboxylate transporter 4 protein contents in the low-oxidative muscles in STZ-induced diabetic mice.
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Affiliation(s)
- A Takemura
- Department of Sports Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan.
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Takahashi K, Kitaoka Y, Hatta H. Effects of endurance training under calorie restriction on energy substrate metabolism in mouse skeletal muscle and liver. J Physiol Sci 2024; 74:32. [PMID: 38849720 PMCID: PMC11157813 DOI: 10.1186/s12576-024-00924-5] [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: 01/07/2024] [Accepted: 05/24/2024] [Indexed: 06/09/2024]
Abstract
We investigated whether calorie restriction (CR) enhances metabolic adaptations to endurance training (ET). Ten-week-old male Institute of Cancer Research (ICR) mice were fed ad libitum or subjected to 30% CR. The mice were subdivided into sedentary and ET groups. The ET group performed treadmill running (20-25 m/min, 30 min, 5 days/week) for 5 weeks. We found that CR decreased glycolytic enzyme activity and monocarboxylate transporter (MCT) 4 protein content, while enhancing glucose transporter 4 protein content in the plantaris and soleus muscles. Although ET and CR individually increased citrate synthase activity in the plantaris muscle, the ET-induced increase in respiratory chain complex I protein content was counteracted by CR. In the soleus muscle, mitochondrial enzyme activity and protein levels were increased by ET, but decreased by CR. It has been suggested that CR partially interferes with skeletal muscle adaptation to ET.
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Affiliation(s)
- Kenya Takahashi
- Department of Sports Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
| | - Yu Kitaoka
- Department of Human Sciences, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama, Kanagawa, 221-8686, Japan
| | - Hideo Hatta
- Department of Sports Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, Tokyo, 153-8902, Japan
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Pinho ACO, Santos D, Oliveira PJ, Leal EC, Carvalho E. Real-time OXPHOS capacity analysis in wounded skin from diabetic mice: A pilot study. Eur J Clin Invest 2024; 54:e14128. [PMID: 37975307 DOI: 10.1111/eci.14128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/25/2023] [Accepted: 11/05/2023] [Indexed: 11/19/2023]
Abstract
INTRODUCTION Diabetes mellitus (DM) impairs wound healing. The aim was to determine whether DM influences mitochondrial respiration in wounded skin (WS) and non-wounded skin (NWS), in a pre-clinical wound healing model of streptozotocin (STZ)-induced diabetes. METHODS Six weeks after diabetes induction, two wounds were created in the back of C57BL/J6 mice. Using high-resolution respirometry (HRR), oxygen flux was measured, in WS and NWS, using two substrate-uncoupler-inhibitor titration protocols, at baseline (day 0), day 3 and 10 post-wounding, in STZ-DM and non-diabetic (NDM) mice. Flux control ratios for the oxidative phosphorylation (OXPHOS) capacity were calculated. RESULTS A significant increase in mitochondrial respiration was observed in STZ-DM skin compared to control skin at baseline. The OXPHOS capacity was decreased in WS under diabetes at day 3 post-wounding (inflammation phase). However, at day 10 post-wounding (remodeling phase), the OXPHOS capacity was higher in WS from STZ-DM compared to NDM mice, and compared to NWS from STZ-DM mice. A significant relative contribution of pyruvate, malate and glutamate (PMG) oxidation to the OXPHOS capacity was observed in WS compared to NWS from STZ-DM mice, at day 10, while the relative contribution of fatty acid oxidation to the OXPHOS capacity was higher in NWS. The OXPHOS capacity is altered in WS from STZ-DM compared to NDM mice across the healing process, and so is the substrate contribution in WS and NWS from STZ-DM mice, at each time point. CONCLUSION HRR may be a sensitive tool to evaluate the underlying mechanisms of tissue repair during wound healing.
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Grants
- DL57/2016/CP1448/ CT0024 Fundação para a Ciência e a Tecnologia (FCT), I. P, Portugal
- POCI-01-0145-FEDER-007440 Fundação para a Ciência e a Tecnologia (FCT), I. P, Portugal
- SFRH/BD/144199/2019 Fundação para a Ciência e a Tecnologia (FCT), I. P, Portugal
- SFRH/BD/145054/2019 Fundação para a Ciência e a Tecnologia (FCT), I. P, Portugal
- UIDB/04539/2020 Fundação para a Ciência e a Tecnologia (FCT), I. P, Portugal
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Affiliation(s)
- Aryane Cruz Oliveira Pinho
- CNC-UC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- CIBB - Center for Inovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal
- Department of Life Sciences, Faculty of Science and Technology, PhD Programme in Biosciences, University of Coimbra, Coimbra, Portugal
| | - Diana Santos
- CNC-UC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- CIBB - Center for Inovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal
- Institute for Interdisciplinary Research, Doctoral Programme in Experimental Biology and Biomedicine (PDBEB), University of Coimbra, Coimbra, Portugal
| | - Paulo J Oliveira
- CNC-UC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- CIBB - Center for Inovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal
| | - Ermelindo Carreira Leal
- CNC-UC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- CIBB - Center for Inovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal
- Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Eugenia Carvalho
- CNC-UC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- CIBB - Center for Inovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal
- Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
- APDP-Portuguese Diabetes Association, Lisbon, Portugal
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Sammut MJ, McBey DP, Sayal AP, Melling CWJ. The Effects of Resistance Exercise Training on Skeletal Muscle Metabolism and Insulin Resistance Development in Female Rodents with Type 1 Diabetes. J Diabetes Res 2024; 2024:5549762. [PMID: 38435452 PMCID: PMC10904684 DOI: 10.1155/2024/5549762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 03/05/2024] Open
Abstract
The etiology of insulin resistance (IR) development in type 1 diabetes mellitus (T1DM) remains unclear; however, impaired skeletal muscle metabolism may play a role. While IR development has been established in male T1DM rodents, female rodents have yet to be examined in this context. Resistance exercise training (RT) has been shown to improve IR and is associated with a lower risk of hypoglycemia onset in T1DM compared to aerobic exercise. The purpose of this study was to investigate the effects of RT on IR development in female T1DM rodents. Forty Sprague Dawley eight-week-old female rats were divided into four groups: control sedentary (CS; n = 10), control trained (CT; n = 10), T1DM sedentary (DS; n = 10), and T1DM trained (DT; n = 10). Multiple low-dose streptozotocin injections were used to induce T1DM. Blood glucose levels were maintained in the 4-9 mmol/l range with intensive insulin therapy. CT and DT underwent weighted ladder climbing 5 days/week for six weeks. Intravenous glucose tolerance tests (IVGTT) were conducted on all animals following the six-week period. Results demonstrate that DS animals exhibited significantly increased weekly blood glucose measures compared to all groups including DT (p < 0.0001), despite similar insulin dosage levels. This was concomitant with a significant increase in insulin-adjusted area under the curve following IVGTT in DS (p < 0.05), indicative of a reduction in insulin sensitivity. Both DT and DS exhibited greater serum insulin concentrations compared to CT and CS (p < 0.05). DS animals also exhibited significantly greater glycogen content in white gastrocnemius muscle compared to CS and DT (p < 0.05), whereas DT and DS animals exhibited greater p-Akt: Akt ratio in the white vastus lateralis muscle and citrate synthase activity in the red vastus lateralis muscle compared to CS and CT (p < 0.05). These results indicate that female rodents with T1DM develop poor glycemic control and IR which can be attenuated with RT, possibly related to differences in intramyocellular glycogen content.
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Affiliation(s)
- Mitchell J. Sammut
- School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada
| | - David P. McBey
- School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada
| | - Amit P. Sayal
- School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada
| | - C. W. James Melling
- School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada
- Department of Physiology & Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
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Kosik B, Larsen S, Bergdahl A. Actovegin improves skeletal muscle mitochondrial respiration and functional aerobic capacity in a type 1 diabetic male murine model. Appl Physiol Nutr Metab 2024; 49:265-272. [PMID: 37913525 DOI: 10.1139/apnm-2023-0004] [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] [Indexed: 11/03/2023]
Abstract
Insulin deficiency in type 1 diabetes (T1D) leads to an impairment of glucose metabolism and mitochondrial function. Actovegin is a hemodialysate of calf blood, which has been shown to enhance glucose uptake and cell metabolism in healthy human skeletal muscle. The objectives of this study were to determine the effects of Actovegin on skeletal muscle mitochondrial respiration and functional aerobic capacity in a T1D mouse model. Effects on the expression of mitochondrial proteins, body mass, and food and water consumption were also investigated. Streptozotocin-induced T1D male C57B1/6 mice (aged 3-4 months) were randomized to an Actovegin group and a control group. Every third day, the Actovegin and control groups were injected intraperitoneally with (0.1 mL) Actovegin and (0.1 mL) physiological salt solution, respectively. Oxidative phosphorylation (OXPHOS) capacity of the vastus lateralis muscle was measured by high resolution respirometry in addition to the expression levels of the mitochondrial complexes as well as voltage-dependent anion channel. Functional aerobic capacity was measured using a rodent treadmill protocol. Body mass and food and water consumption were also measured. After 13 days, in comparison to the control group, the Actovegin group demonstrated a significantly higher skeletal muscle mitochondrial respiratory capacity in an ADP-restricted and ADP-stimulated environment. The Actovegin group displayed a significantly lesser decline in functional aerobic capacity and baseline body mass after 13 days. There were no significant differences in food or water consumption between groups. Actovegin could act as an effective agent for facilitating glucose metabolism and improving OXPHOS capacity and functional aerobic capacity in T1D. Further investigation is warranted to establish Actovegin's potential as an alternative therapeutic drug for T1D.
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Affiliation(s)
- Brandon Kosik
- Department of Health, Kinesiology and Applied Physiology, Concordia University, Montreal, Canada
| | - Steen Larsen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Clinical Research Centre, Medical University of Bialystok, Bialystok, Poland
| | - Andreas Bergdahl
- Department of Health, Kinesiology and Applied Physiology, Concordia University, Montreal, Canada
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Bosso M, Haddad D, Al Madhoun A, Al-Mulla F. Targeting the Metabolic Paradigms in Cancer and Diabetes. Biomedicines 2024; 12:211. [PMID: 38255314 PMCID: PMC10813379 DOI: 10.3390/biomedicines12010211] [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: 11/29/2023] [Revised: 01/09/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Dysregulated metabolic dynamics are evident in both cancer and diabetes, with metabolic alterations representing a facet of the myriad changes observed in these conditions. This review delves into the commonalities in metabolism between cancer and type 2 diabetes (T2D), focusing specifically on the contrasting roles of oxidative phosphorylation (OXPHOS) and glycolysis as primary energy-generating pathways within cells. Building on earlier research, we explore how a shift towards one pathway over the other serves as a foundational aspect in the development of cancer and T2D. Unlike previous reviews, we posit that this shift may occur in seemingly opposing yet complementary directions, akin to the Yin and Yang concept. These metabolic fluctuations reveal an intricate network of underlying defective signaling pathways, orchestrating the pathogenesis and progression of each disease. The Warburg phenomenon, characterized by the prevalence of aerobic glycolysis over minimal to no OXPHOS, emerges as the predominant metabolic phenotype in cancer. Conversely, in T2D, the prevailing metabolic paradigm has traditionally been perceived in terms of discrete irregularities rather than an OXPHOS-to-glycolysis shift. Throughout T2D pathogenesis, OXPHOS remains consistently heightened due to chronic hyperglycemia or hyperinsulinemia. In advanced insulin resistance and T2D, the metabolic landscape becomes more complex, featuring differential tissue-specific alterations that affect OXPHOS. Recent findings suggest that addressing the metabolic imbalance in both cancer and diabetes could offer an effective treatment strategy. Numerous pharmaceutical and nutritional modalities exhibiting therapeutic effects in both conditions ultimately modulate the OXPHOS-glycolysis axis. Noteworthy nutritional adjuncts, such as alpha-lipoic acid, flavonoids, and glutamine, demonstrate the ability to reprogram metabolism, exerting anti-tumor and anti-diabetic effects. Similarly, pharmacological agents like metformin exhibit therapeutic efficacy in both T2D and cancer. This review discusses the molecular mechanisms underlying these metabolic shifts and explores promising therapeutic strategies aimed at reversing the metabolic imbalance in both disease scenarios.
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Affiliation(s)
- Mira Bosso
- Department of Pathology, Faculty of Medicine, Health Science Center, Kuwait University, Safat 13110, Kuwait
| | - Dania Haddad
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Dasman 15462, Kuwait; (D.H.); (A.A.M.)
| | - Ashraf Al Madhoun
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Dasman 15462, Kuwait; (D.H.); (A.A.M.)
- Department of Animal and Imaging Core Facilities, Dasman Diabetes Institute, Dasman 15462, Kuwait
| | - Fahd Al-Mulla
- Department of Pathology, Faculty of Medicine, Health Science Center, Kuwait University, Safat 13110, Kuwait
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Dasman 15462, Kuwait; (D.H.); (A.A.M.)
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7
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Christensen IB, Blom I, Dohlmann TL, Finger F, Helge JW, Gerhart-Hines Z, Dela F, Larsen S. Effect of Simvastatin Treatment on Mitochondrial Function and Inflammatory Status of Human White Adipose Tissue. J Clin Endocrinol Metab 2023; 108:e916-e922. [PMID: 37161534 DOI: 10.1210/clinem/dgad259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 02/20/2023] [Accepted: 05/08/2023] [Indexed: 05/11/2023]
Abstract
BACKGROUND Statin therapy has shown pleiotropic effects affecting both mitochondrial function and inflammatory status. However, few studies have investigated the concurrent effects of statin exposure on mitochondrial function and inflammatory status in human subcutaneous white adipose tissue. OBJECTIVES In a cross-sectional study, we investigated the effects of simvastatin on mitochondrial function and inflammatory status in subcutaneous white adipose tissue of 55 human participants: 38 patients (19 females/19 males) in primary prevention with simvastatin (> 40 mg/d, > 3 mo) and 17 controls (9 females/8 males) with elevated plasma cholesterol. The 2 groups were matched on age, body mass index, and maximal oxygen consumption. METHODS Anthropometrics and fasting biochemical characteristics were measured. Mitochondrial respiratory capacity was assessed in white adipose tissue by high-resolution respirometry. Subcutaneous white adipose tissue expression of the inflammatory markers IL-6, chemokine (C-C motif) ligand 2 (CCL2), CCL-5, tumor necrosis factor-α, IL-10, and IL-4 was analyzed by quantitative PCR. RESULTS Simvastatin-treated patients showed lower plasma cholesterol (P < .0001), low-density lipoprotein (P < .0001), and triglyceride levels (P = .0116) than controls. Simvastatin-treated patients had a lower oxidative phosphorylation capacity of mitochondrial complex II (P = .0001 when normalized to wet weight, P < .0001 when normalized to citrate synthase activity [intrinsic]), and a lower intrinsic mitochondrial electron transport system capacity (P = .0004). Simvastatin-treated patients showed higher IL-6 expression than controls (P = .0202). CONCLUSION Simvastatin treatment was linked to mitochondrial respiratory capacity in human subcutaneous white adipose tissue, but no clear link was found between statin exposure, respiratory changes, and inflammatory status of adipose tissue.
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Affiliation(s)
- Ida Bager Christensen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Ida Blom
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Tine Lovsø Dohlmann
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
- Department of Epidemiology Research, Statens Serum Institut, 2300 Copenhagen S, Denmark
| | - Fabian Finger
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Jørn W Helge
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Zachary Gerhart-Hines
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Flemming Dela
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
- Department of Geriatrics, Bispebjerg-Frederiksberg University Hospital, 2400 Copenhagen NV, Denmark
| | - Steen Larsen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
- Clinical Research Centre, Medical University of Bialystok, 15-089 Białystok, Poland
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Galambo D, Bergdahl A. Physiological levels of cardiolipin acutely affect mitochondrial respiration in vascular smooth muscle cells. Curr Res Physiol 2022; 6:100097. [PMID: 36594049 PMCID: PMC9803913 DOI: 10.1016/j.crphys.2022.100097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 12/03/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022] Open
Abstract
Cardiolipin (CL) is a phospholipid molecule found in the inner mitochondrial membrane, where it normally associates with and activates the respiratory complexes. Following myocardial infarction, CL gets released from necrotic cells, consequently affecting neighboring tissues. We have previously demonstrated that physiological concentrations of up to 100 μM CL diminish endothelial cell migration and angiogenic sprouting. Since CL is vital to cellular life, we hypothesized that this molecule may have considerable implications on vascular smooth muscle cells bioenergetics, a key phase in atherogenesis. We examined the acute effects of physiological concentrations of CL on oxidative phosphorylation in permeabilized mice aorta using high-resolution respirometry and a substrate-inhibitor titration protocol. We found that CL significantly lowers LEAK and maximal State 3 respiration. In addition, we found that the acceptor control ratio, representing the coupling between oxidation and phosphorylation, was significantly upregulated by CL. Our findings demonstrate that in situ mitochondrial respiration in permeabilized smooth muscle cells is attenuated when physiological concentrations of CL are applied acutely. This could provide a novel therapy to reduce their dedifferentiation and consequently atherogenesis.
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Affiliation(s)
- Deema Galambo
- Department of Biology, Concordia, Montreal, QC, Canada
| | - Andreas Bergdahl
- Department of Health, Kinesiology & Applied Physiology, Concordia University, Montreal, QC, Canada
- Corresponding author.
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9
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Takahashi K, Tamura Y, Kitaoka Y, Matsunaga Y, Hatta H. Effects of Lactate Administration on Mitochondrial Respiratory Function in Mouse Skeletal Muscle. Front Physiol 2022; 13:920034. [PMID: 35845998 PMCID: PMC9280083 DOI: 10.3389/fphys.2022.920034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/09/2022] [Indexed: 11/27/2022] Open
Abstract
Recent evidence has shown that mitochondrial respiratory function contributes to exercise performance and metabolic health. Given that lactate is considered a potential signaling molecule that induces mitochondrial adaptations, we tested the hypothesis that lactate would change mitochondrial respiratory function in skeletal muscle. Male ICR mice (8 weeks old) received intraperitoneal injection of PBS or sodium lactate (1 g/kg BW) 5 days a week for 4 weeks. Mitochondria were isolated from freshly excised gastrocnemius muscle using differential centrifugation and were used for all analyses. Lactate administration significantly enhanced pyruvate + malate- and glutamate + malate-induced (complex I-driven) state 3 (maximal/ATP synthesis-coupled) respiration, but not state 2 (basal/proton conductance) respiration. In contrast, lactate administration significantly decreased succinate + rotenone-induced (complex II-driven) state 3 and 2 respiration. No significant differences were observed in malate + octanoyl-l-carnitine-induced state 3 or 2 respiration. The enzymatic activity of complex I was tended to increase and those of complexes I + III and IV were significantly increased after lactate administration. No differences were observed in the activities of complexes II or II + III. Moreover, lactate administration increased the protein content of NDUFS4, a subunit of complex I, but not those of the other components. The present findings suggest that lactate alters mitochondrial respiratory function in skeletal muscle.
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Affiliation(s)
- Kenya Takahashi
- Department of Sports Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuki Tamura
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Yu Kitaoka
- Department of Human Sciences, Kanagawa University, Yokohama, Japan
| | - Yutaka Matsunaga
- Department of Sports Sciences, The University of Tokyo, Tokyo, Japan
| | - Hideo Hatta
- Department of Sports Sciences, The University of Tokyo, Tokyo, Japan
- *Correspondence: Hideo Hatta,
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10
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Shang R, Lal N, Lee CS, Zhai Y, Puri K, Seira O, Boushel RC, Sultan I, Räsänen M, Alitalo K, Hussein B, Rodrigues B. Cardiac-specific VEGFB overexpression reduces lipoprotein lipase activity and improves insulin action in rat heart. Am J Physiol Endocrinol Metab 2021; 321:E753-E765. [PMID: 34747201 DOI: 10.1152/ajpendo.00219.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac muscle uses multiple sources of energy including glucose and fatty acid (FA). The heart cannot synthesize FA and relies on obtaining it from other sources, with lipoprotein lipase (LPL) breakdown of lipoproteins suggested to be a key source of FA for cardiac use. Recent work has indicated that cardiac vascular endothelial growth factor B (VEGFB) overexpression expands the coronary vasculature and facilitates metabolic reprogramming that favors glucose utilization. We wanted to explore whether this influence of VEGFB on cardiac metabolism involves regulation of LPL activity with consequent effects on lipotoxicity and insulin signaling. The transcriptomes of rats with and without cardiomyocyte-specific overexpression of human VEGFB were compared by using RNA sequencing. Isolated perfused hearts or cardiomyocytes incubated with heparin were used to enable measurement of LPL activity. Untargeted metabolomic analysis was performed for quantification of cardiac lipid metabolites. Cardiac insulin sensitivity was evaluated using fast-acting insulin. Isolated heart and cardiomyocytes were used to determine transgene-encoded VEGFB isoform secretion patterns and mitochondrial oxidative capacity using high-resolution respirometry and extracellular flux analysis. In vitro, transgenic cardiomyocytes incubated overnight and thus exposed to abundantly secreted VEGFB isoforms, in the absence of any in vivo confounding regulators of cardiac metabolism, demonstrated higher basal oxygen consumption. In the whole heart, VEGFB overexpression induced an angiogenic response that was accompanied by limited cardiac LPL activity through multiple mechanisms. This was associated with a lowered accumulation of lipid intermediates, diacylglycerols and lysophosphatidylcholine, that are known to influence insulin action. In response to exogenous insulin, transgenic hearts demonstrated increased insulin sensitivity. In conclusion, the interrogation of VEGFB function on cardiac metabolism uncovered an intriguing and previously unappreciated effect to lower LPL activity and prevent lipid metabolite accumulation to improve insulin action. VEGFB could be a potential cardioprotective therapy to treat metabolic disorders, for example, diabetes.NEW & NOTEWORTHY In hearts overexpressing vascular endothelial growth factor B (VEGFB), besides its known angiogenic response, multiple regulatory mechanisms lowered coronary LPL. This was accompanied by limited cardiac lipid metabolite accumulation with an augmentation of cardiac insulin action. Our data for the first time links VEGFB to coronary LPL in regulation of cardiac metabolism. VEGFB may be cardioprotective in metabolic disorders like diabetes.
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Affiliation(s)
- Rui Shang
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nathaniel Lal
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chae Syng Lee
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yajie Zhai
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Karanjit Puri
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Oscar Seira
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Robert C Boushel
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ibrahim Sultan
- Wihuri Research Institute and Translational Cancer Medicine Program, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Markus Räsänen
- Wihuri Research Institute and Translational Cancer Medicine Program, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Kari Alitalo
- Wihuri Research Institute and Translational Cancer Medicine Program, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Bahira Hussein
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian Rodrigues
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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Monaco CMF, Tarnopolsky MA, Dial AG, Nederveen JP, Rebalka IA, Nguyen M, Turner LV, Perry CGR, Ljubicic V, Hawke TJ. Normal to enhanced intrinsic mitochondrial respiration in skeletal muscle of middle- to older-aged women and men with uncomplicated type 1 diabetes. Diabetologia 2021; 64:2517-2533. [PMID: 34392397 DOI: 10.1007/s00125-021-05540-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 05/20/2021] [Indexed: 12/26/2022]
Abstract
AIMS/HYPOTHESIS This study interrogated mitochondrial respiratory function and content in skeletal muscle biopsies of healthy adults between 30 and 72 years old with and without uncomplicated type 1 diabetes. METHODS Participants (12 women/nine men) with type 1 diabetes (48 ± 11 years of age), without overt complications, were matched for age, sex, BMI and level of physical activity to participants without diabetes (control participants) (49 ± 12 years of age). Participants underwent a Bergström biopsy of the vastus lateralis to assess mitochondrial respiratory function using high-resolution respirometry and citrate synthase activity. Electron microscopy was used to quantify mitochondrial content and cristae (pixel) density. RESULTS Mean mitochondrial area density was 27% lower (p = 0.006) in participants with type 1 diabetes compared with control participants. This was largely due to smaller mitochondrial fragments in women with type 1 diabetes (-18%, p = 0.057), as opposed to a decrease in the total number of mitochondrial fragments in men with diabetes (-28%, p = 0.130). Mitochondrial respiratory measures, whether estimated per milligram of tissue (i.e. mass-specific) or normalised to area density (i.e. intrinsic mitochondrial function), differed between cohorts, and demonstrated sexual dimorphism. Mass-specific mitochondrial oxidative phosphorylation (OXPHOS) capacity with the substrates for complex I and complex II (CI + II) was significantly lower (-24%, p = 0.033) in women with type 1 diabetes compared with control participants, whereas mass-specific OXPHOS capacities with substrates for complex I only (pyruvate [CI pyr] or glutamate [CI glu]) or complex II only (succinate [CII succ]) were not different (p > 0.404). No statistical differences (p > 0.397) were found in mass-specific OXPHOS capacity in men with type 1 diabetes compared with control participants despite a 42% non-significant increase in CI glu OXPHOS capacity (p = 0.218). In contrast, intrinsic CI + II OXPHOS capacity was not different in women with type 1 diabetes (+5%, p = 0.378), whereas in men with type 1 diabetes it was 25% higher (p = 0.163) compared with control participants. Men with type 1 diabetes also demonstrated higher intrinsic OXPHOS capacity for CI pyr (+50%, p = 0.159), CI glu (+88%, p = 0.033) and CII succ (+28%, p = 0.123), as well as higher intrinsic respiratory rates with low (more physiological) concentrations of either ADP, pyruvate, glutamate or succinate (p < 0.012). Women with type 1 diabetes had higher (p < 0.003) intrinsic respiratory rates with low concentrations of succinate only. Calculated aerobic fitness (Physical Working Capacity Test [PWC130]) showed a strong relationship with mitochondrial respiratory function and content in the type 1 diabetes cohort. CONCLUSIONS/INTERPRETATION In middle- to older-aged adults with uncomplicated type 1 diabetes, we conclude that skeletal muscle mitochondria differentially adapt to type 1 diabetes and demonstrate sexual dimorphism. Importantly, these cellular alterations were significantly associated with our metric of aerobic fitness (PWC130) and preceded notable impairments in skeletal mass and strength.
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Affiliation(s)
- Cynthia M F Monaco
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | | | - Athan G Dial
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | | | - Irena A Rebalka
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Maria Nguyen
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Lauren V Turner
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Christopher G R Perry
- School of Kinesiology and Health Sciences, Muscle Health Research Centre, York University, Toronto, ON, Canada
| | - Vladimir Ljubicic
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - Thomas J Hawke
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada.
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12
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Hansen C, Olsen K, Pilegaard H, Bangsbo J, Gliemann L, Hellsten Y. High metabolic substrate load induces mitochondrial dysfunction in rat skeletal muscle microvascular endothelial cells. Physiol Rep 2021; 9:e14855. [PMID: 34288561 PMCID: PMC8290479 DOI: 10.14814/phy2.14855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/01/2021] [Accepted: 03/03/2021] [Indexed: 12/21/2022] Open
Abstract
The influence of glucose and palmitic acid (PA) on mitochondrial respiration and emission of hydrogen peroxide (H2 O2 ) was determined in skeletal muscle-derived microvascular endothelial cells. Measurements were assessed in intact and permeabilized (cells treated with 0.025% saponin) low passage endothelial cells with acute-or prolonged (3 days) incubation with regular (1.7 mM) or elevated (2.2 mM) PA concentrations and regular (5 mM) or elevated (11 mM) glucose concentrations. In intact cells, acute incubation with 1.7 mM PA alone or with 1.7 mM PA + 5 mM glucose (p < .001) led to a lower mitochondrial respiration (p < 0.01) and markedly higher H2 O2 /O2 emission (p < 0.05) than with 5 mM glucose alone. Prolonged incubation of intact cells with 1.7 mM PA +5 mM glucose led to 34% (p < 0.05) lower respiration and 2.5-fold higher H2 O2 /O2 emission (p < 0.01) than incubation with 5 mM glucose alone. Prolonged incubation of intact cells with elevated glucose led to 60% lower (p < 0.05) mitochondrial respiration and 4.6-fold higher H2 O2 /O2 production than incubation with 5 mM glucose in intact cells (p < 0.001). All effects observed in intact cells were present also in permeabilized cells (State 2). In conclusion, our results show that acute and prolonged lipid availability, as well as prolonged hyperglycemia, induces mitochondrial dysfunction as evidenced by lower mitochondrial respiration and enhanced H2 O2/ O2 emission. Elevated plasma substrate availability may lead to microvascular dysfunction in skeletal muscle by impairing endothelial mitochondrial function.
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Affiliation(s)
- Camilla Hansen
- Department of Nutrition, Exercise and SportsCardiovascular Physiology GroupSection of Integrative PhysiologyUniversity of CopenhagenCopenhagenDenmark
| | - Karina Olsen
- Department of Nutrition, Exercise and SportsCardiovascular Physiology GroupSection of Integrative PhysiologyUniversity of CopenhagenCopenhagenDenmark
| | - Henriette Pilegaard
- Department of BiologySection of Cell Biology and PhysiologyUniversity of CopenhagenCopenhagenDenmark
| | - Jens Bangsbo
- Department of Nutrition, Exercise and SportsSection of Integrative PhysiologyUniversity of CopenhagenCopenhagenDenmark
| | - Lasse Gliemann
- Department of Nutrition, Exercise and SportsCardiovascular Physiology GroupSection of Integrative PhysiologyUniversity of CopenhagenCopenhagenDenmark
| | - Ylva Hellsten
- Department of Nutrition, Exercise and SportsCardiovascular Physiology GroupSection of Integrative PhysiologyUniversity of CopenhagenCopenhagenDenmark
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13
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Genders AJ, Holloway GP, Bishop DJ. Are Alterations in Skeletal Muscle Mitochondria a Cause or Consequence of Insulin Resistance? Int J Mol Sci 2020; 21:ijms21186948. [PMID: 32971810 PMCID: PMC7554894 DOI: 10.3390/ijms21186948] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 09/18/2020] [Accepted: 09/18/2020] [Indexed: 12/14/2022] Open
Abstract
As a major site of glucose uptake following a meal, skeletal muscle has an important role in whole-body glucose metabolism. Evidence in humans and animal models of insulin resistance and type 2 diabetes suggests that alterations in mitochondrial characteristics accompany the development of skeletal muscle insulin resistance. However, it is unclear whether changes in mitochondrial content, respiratory function, or substrate oxidation are central to the development of insulin resistance or occur in response to insulin resistance. Thus, this review will aim to evaluate the apparent conflicting information placing mitochondria as a key organelle in the development of insulin resistance in skeletal muscle.
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Affiliation(s)
- Amanda J. Genders
- Institute for Health and Sport (iHeS), Victoria University, Melbourne 8001, Australia;
- Correspondence: ; Tel.: +61-3-9919-9556
| | - Graham P. Holloway
- Dept. Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada;
| | - David J. Bishop
- Institute for Health and Sport (iHeS), Victoria University, Melbourne 8001, Australia;
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14
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Miotto PM, Petrick HL, Holloway GP. Acute insulin deprivation results in altered mitochondrial substrate sensitivity conducive to greater fatty acid transport. Am J Physiol Endocrinol Metab 2020; 319:E345-E353. [PMID: 32543943 PMCID: PMC7473910 DOI: 10.1152/ajpendo.00495.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Type 1 and type 2 diabetes are both tightly associated with impaired glucose control. Although both pathologies stem from different mechanisms, a reduction in insulin action coincides with drastic metabolic dysfunction in skeletal muscle and metabolic inflexibility. However, the underlying explanation for this response remains poorly understood, particularly since it is difficult to distinguish the role of attenuated insulin action from the detrimental effects of reactive lipid accumulation, which impairs mitochondrial function and promotes reactive oxygen species (ROS) emission. We therefore utilized streptozotocin to examine the effects of acute insulin deprivation, in the absence of a high-lipid/nutrient excess environment, on the regulation of mitochondrial substrate sensitivity and ROS emission. The ablation of insulin resulted in reductions in absolute mitochondrial oxidative capacity and ADP-supported respiration and reduced the ability for malonyl-CoA to inhibit carnitine palmitoyltransferase I (CPT-I) and suppress fatty acid-supported respiration. These bioenergetic responses coincided with increased mitochondrial-derived H2O2 emission and lipid transporter content, independent of major mitochondrial substrate transporter proteins and enzymes involved in fatty acid oxidation. Together, these data suggest that attenuated/ablated insulin signaling does not affect mitochondrial ADP sensitivity, whereas the increased reliance on fatty acid oxidation in situations where insulin action is reduced may occur as a result of altered regulation of mitochondrial fatty acid transport through CPT-I.
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Affiliation(s)
- Paula M Miotto
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Heather L Petrick
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Graham P Holloway
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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15
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Ko E, Kim D, Kim K, Choi M, Shin S. The action of low doses of persistent organic pollutants (POPs) on mitochondrial function in zebrafish eyes and comparison with hyperglycemia to identify a link between POPs and diabetes. Toxicol Mech Methods 2020; 30:275-283. [DOI: 10.1080/15376516.2020.1717704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Eun Ko
- Interdisciplinary Program of Bioenergy and Biomaterials Graduate School, College of Engineering, Chonnam National University, Gwangju, Republic of Korea
| | - Dayoung Kim
- Interdisciplinary Program of Bioenergy and Biomaterials Graduate School, College of Engineering, Chonnam National University, Gwangju, Republic of Korea
| | - Kitae Kim
- Department of Environmental Engineering, College of Energy and Biotechnology, Seoul National University of Science and Technology, Seoul, Republic of Korea
| | - Moonsung Choi
- Department of Optometry, College of Energy and Biotechnology, Seoul National University of Science and Technology, Seoul, Republic of Korea
| | - Sooim Shin
- Interdisciplinary Program of Bioenergy and Biomaterials Graduate School, College of Engineering, Chonnam National University, Gwangju, Republic of Korea
- Department of Biotechnology and Bioengineering, College of Engineering, Chonnam National University, Gwangju, Republic of Korea
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16
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Cardiac mitochondrial respiration following a low-carbohydrate, high-fat diet in apolipoprotein E-deficient mice. J Physiol Biochem 2018; 75:65-72. [PMID: 30362048 DOI: 10.1007/s13105-018-0653-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 10/10/2018] [Indexed: 01/13/2023]
Abstract
Low-carbohydrate diets are considered to be an effective approach to weight loss and have, subsequently, grown in popularity. Despite the apparent health benefits that these diets may provide for insulin resistance, hypertension, and dyslipidemia, their implications on cardiomyocyte oxidative capacity have yet to be investigated. To evaluate the adaptations induced by a 6-week low-carbohydrate, high-fat (LCHF) diet on mitochondrial respiration, two groups of male mice were investigated: Apolipoprotein E-deficient mice on a LCHF diet (L-DIET) and apolipoprotein E-deficient mice on a regular rodent diet (CON). Heart tissue was extracted and used for high-resolution respirometry (HRR), while immunoblotting was performed to quantify mitochondrial density and complexes. The results demonstrate increased expression of all five mitochondrial subunits in the L-DIET group compared to control condition. Furthermore, HRR revealed increased efficiency of substrate consumption, implying augmented oxidative capacity in the L-DIET group. These findings further support the notion that cardiomyocytes prefer lipids as a primary fuel source, by demonstrating that the shift in metabolism caused by a LCHF diet facilitates such an environment. This provides important information regarding the effects of a LCHF on cardiomyocytes, especially when considering free radical production and heart dysfunction.
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17
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Mondragon P, Bergdahl A. Metallothionein expression in slow- vs. fast-twitch muscle fibers following 4 weeks of streptozotocin-induced type 1 diabetes. Facets (Ott) 2018. [DOI: 10.1139/facets-2017-0058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Type 1 diabetes (T1DM) is known to cause an increase in reactive oxygen species (ROS) and elevated intracellular glucose levels. We investigated the metallothionein I and II (MT I+II) antioxidants expression in soleus (mainly slow-twitch) and plantaris (predominantly fast-twitch) skeletal muscle using a rodent model of streptozotocin-induced diabetes. The presence of oxidative stress was confirmed by the detection of increased levels of protein carbonyl formation in the diabetic tissues. DAB (3,3′-diaminobenzidine) immunostaining and Western blotting analyses demonstrated that MT I+II expression was significantly upregulated in the diabetic soleus and plantaris muscle tissues compared with their respective controls. Moreover, no significant difference was detected between the plantaris and soleus controls or between the plantaris and soleus diabetic tissues. These findings suggest that there is an increase in MT protein expression in the soleus and plantaris muscles associated with the induction of T1DM. A better understanding of the molecular mechanisms that allow MT to prevent the oxidative stress associated with diabetes could lead to a novel therapeutic strategy for this chronic disease and its associated complications.
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Affiliation(s)
- Pamela Mondragon
- Department of Exercise Science, Concordia University, 7141 Sherbrooke West, Montreal, QC H4B 1R6, Canada
| | - Andreas Bergdahl
- Department of Exercise Science, Concordia University, 7141 Sherbrooke West, Montreal, QC H4B 1R6, Canada
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18
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Scheede-Bergdahl C, Bergdahl A. Adaptation of mitochondrial expression and ATP production in dedifferentiating vascular smooth muscle cells. Can J Physiol Pharmacol 2017; 95:1473-1479. [PMID: 28846852 DOI: 10.1139/cjpp-2017-0227] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Atherosclerosis is one of the leading causes of morbidity and mortality in the Western world. Although the clinical manifestations of this disease are well documented, the etiology and progression remain to be fully understood. Recently, the mitochondria have been implicated in important cellular processes involved in development of atherosclerosis. Despite the link between mitochondria and atherosclerosis, early-phase mechanisms of the disease have yet to be elucidated. The aim of this project was to explore the role of mitochondria in vascular smooth muscle (VSMC) dedifferentiation. A murine in vitro model, involving organ culture of aortic tissue in serum-free media, was used. Mitochondrial function was measured by high-resolution respirometry. Proteins associated with the VSMC phenotype switch, as well as mitochondrial density, were assessed by immunoblotting. The findings show that intrinsic mitochondrial Complex I activity is significantly upregulated during VSMC dedifferentiation. Diminished coupling between phosphorylation and oxidation was also found, indicating a greater ADP:ATP ratio. This data suggests increased leak in the electron transport chain and altered mitochondrial function specifically at Complex I. This project provides important information regarding the role of mitochondria in the early atherosclerotic process and that detectable changes in mitochondrial function and expression are related to VSMC dedifferentiation.
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Affiliation(s)
- Celena Scheede-Bergdahl
- a Department of Kinesiology & Physical Education, McGill University, Montreal, QC H2W 1S4, Canada.,b McGill Research Centre for Physical Activity & Health, McGill University, Montreal, QC H2W 1S4, Canada
| | - Andreas Bergdahl
- c Department of Exercise Science, Concordia University, Montreal, QC H4B 1R6, Canada
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19
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Snook LA, Wright DC, Holloway GP. Postprandial control of fatty acid transport proteins' subcellular location is not dependent on insulin. FEBS Lett 2016; 590:2661-70. [PMID: 27311759 DOI: 10.1002/1873-3468.12260] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 04/28/2016] [Accepted: 06/14/2016] [Indexed: 01/09/2023]
Abstract
Fatty acid transport proteins rapidly translocate to the plasma membrane in response to various stimuli, including insulin, influencing lipid uptake into muscle. However, our understanding of the mechanisms regulating postprandial fatty acid transporter subcellular location remains limited. We demonstrate that the response of fatty acid transporters to insulin stimulation is extremely brief and not temporally matched in the postprandial state. We further show that high-fat diet-induced accumulation of fatty acid transporters on the plasma membrane can occur in the absence of insulin. Altogether, these data suggest that insulin is not the primary signal regulating fatty acid transporter relocation in vivo.
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Affiliation(s)
- Laelie A Snook
- Department of Human Health and Nutritional Sciences, University of Guelph, Canada
| | - David C Wright
- Department of Human Health and Nutritional Sciences, University of Guelph, Canada
| | - Graham P Holloway
- Department of Human Health and Nutritional Sciences, University of Guelph, Canada
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