scholarly journals Naked mole-rats suppress energy metabolism and modulate membrane cholesterol in chronic hypoxia

2020 ◽  
Vol 319 (2) ◽  
pp. R148-R155
Author(s):  
Elie Farhat ◽  
Maiah E. M. Devereaux ◽  
Matthew E. Pamenter ◽  
Jean-Michel Weber
Keyword(s):  
Energy Metabolism ◽  
Metabolic Rate ◽  
Chronic Hypoxia ◽  
Membrane Lipids ◽  
Tca Cycle ◽  
Hypoxia Tolerance ◽  
Membrane Cholesterol ◽  
Functional Link ◽  
Sodium Potassium ◽  
Potassium Atpase

Naked mole-rats (NMRs) are mammalian champions of hypoxia tolerance that enter metabolic suppression to survive in low oxygen environments. Common physiological mechanisms used by animals to suppress metabolic rate include downregulating energy metabolism (ATP supply) as well as ion pumps (primary cellular ATP consumers). A recent goldfish study demonstrated that remodeling of membrane lipids may mediate these responses, but it is unknown if NMR employs the same strategies; therefore, we aimed to test the hypotheses that these fossorial mammals 1) downregulate the activity of key enzymes of glycolysis, tricarboxylic acid (TCA) cycle, and β-oxidation, 2) inhibit sodium-potassium-ATPase, and 3) alter membrane lipids in response to chronic hypoxia. We found that NMRs exposed to 11% oxygen for 4 wk had a lower metabolic rate by 34%. This suppression occurs concurrently with tissue-specific 25–99% decreases in metabolic enzymes activities, a 77% decrease in brain sodium/potassium-ATPase activity, and widespread changes in membrane cholesterol abundance. By reducing glycolytic and β-oxidation fluxes, NMRs decrease the supply of acetyl-CoA to the TCA cycle. By contrast, there is a 94% upregulation of citrate synthase in the heart, possibly to support circulation and thus oxygen supply to other organs. Taken together, these responses may reflect a coordinated physiological response to hypoxia, but a clear functional link between changes in membrane composition and enzyme activities could not be established. Nevertheless, this is the first demonstration that hypometabolic NMRs alter the lipid composition of their membranes in response to chronic in vivo exposure to hypoxia.

scholarly journals Chronic hypoxia increases rat diaphragm muscle endurance and sodium-potassium ATPase pump content

2010 ◽  
Vol 37 (6) ◽  
pp. 1474-1481 ◽  
Author(s):  
C. McMorrow ◽  
A. Fredsted ◽  
J. Carberry ◽  
R. A. O'Connell ◽  
A. Bradford ◽  
...  
Keyword(s):  
Chronic Hypoxia ◽  
Diaphragm Muscle ◽  
Muscle Endurance ◽  
Rat Diaphragm ◽  
Sodium Potassium ◽  
Potassium Atpase

scholarly journals Hypometabolic Responses to Chronic Hypoxia: A Potential Role for Membrane Lipids

Metabolites ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 503
Author(s):  
Elie Farhat ◽  
Jean-Michel Weber
Keyword(s):  
Chronic Hypoxia ◽  
Membrane Lipids ◽  
Supply And Demand ◽  
Hypoxia Tolerance ◽  
Ion Pumps ◽  
Low Oxygen ◽  
Homeoviscous Adaptation ◽  
Metabolic Suppression ◽  
Atp Supply

Metabolic suppression is an essential strategy to cope with chronic hypoxia. This review examines the physiological processes used to survive in low oxygen environments. It proposes a novel mechanism–the remodeling of membrane lipids–to suppress ATP use and production. Temperature (homeoviscous adaptation), diet (natural doping in migrant birds) and body mass (membrane pacemaker of metabolism) have an impact on the lipid composition of membranes, which, in turn, modulates metabolic capacity. Vertebrate champions of hypoxia tolerance show extensive changes in membrane lipids upon in vivo exposure to low oxygen. These changes and those observed in hibernating mammals can promote the downregulation of ion pumps (major ATP consumers), ion channels, mitochondrial respiration capacity (state 3, proton leak, cytochrome c oxidase), and energy metabolism (β-oxidation and glycolysis). A common membrane signal regulating the joint inhibition of ion pumps and channels could be an exquisite way to preserve the balance between ATP supply and demand in hypometabolic states. Membrane remodeling together with more traditional mechanisms could work in concert to cause metabolic suppression.

Adenosine Receptor Modulation of Hypoxic-ischemic Injury in Striatum of Newborn Piglets

2020 ◽  
Vol 17 (4) ◽  
pp. 510-517
Author(s):  
Santiago Ortega-Gutierrez ◽  
Brandy Jones ◽  
Alan Mendez-Ruiz ◽  
Pankhil Shah ◽  
Michel T. Torbey
Keyword(s):  
Oxidative Stress ◽  
Atpase Activity ◽  
Neuronal Injury ◽  
Receptor Activation ◽  
Adult Mortality ◽  
Vehicle Group ◽  
Sodium Potassium ◽  
Receptor Modulation ◽  
A2a Receptor ◽  
Potassium Atpase

Background: Hypoxic-ischemic encephalopathy (HIE) is a major cause of pediatric and adult mortality and morbidity. Unfortunately, to date, no effective treatment has been identified. In the striatum, neuronal injury is analogous to the cellular mechanism of necrosis observed during NMethyl- D-Aspartate (NMDA) excitotoxicity. Adenosine acts as a neuromodulator in the central nervous system, the role of which relies mostly on controlling excitatory glutamatergic synapses. Objective: To examine the effect of pretreatment of SCH58261, an adenosine 2A (A2A) receptor antagonist and modulator of NMDA receptor function, following hypoxic-ischemia (HI) on sodium- potassium ATPase (Na+, K+-ATPase) activity and oxidative stress. Methods: Piglets (4-7 days old) were subjected to 30 min hypoxia and 7 min of airway occlusion producing asphyxic cardiac arrest. Groups were divided into four categories: HI samples were divided into HI-vehicle group (n = 5) and HI-A2A group (n = 5). Sham controls were divided into Sham vehicle (n = 5) and Sham A2A (n = 5) groups. Vehicle groups were pretreated with 0.9% saline, whereas A2A animals were pretreated with SCH58261 10 min prior to intervention. Striatum samples were collected 3 h post-arrest. Sodium-potassium ATPase (Na+, K+-ATPase) activity, malondialdehyde (MDA) + 4-hydroxyalkenals (4-HDA) and glutathione (GSH) levels were compared. Results: Pretreatment with SCH58261 significantly attenuated the decrease in Na+, K+-ATPase, decreased MDA+4-HDA levels and increased GSH in the HI-A2A group when compared to HIvehicle. Conclusion: A2A receptor activation may contribute to neuronal injury in newborn striatum after HI in association with decreased Na+, K+-ATPase activity and increased oxidative stress.

scholarly journals Characterization and partial purification of the sodium-potassium-ATPase inhibitor released from cultured rat hypothalamic cells.

1985 ◽  
Vol 260 (25) ◽  
pp. 13595-13600 ◽  
Author(s):  
K Morgan ◽  
M D Lewis ◽  
G Spurlock ◽  
P A Collins ◽  
S M Foord ◽  
...  
Keyword(s):  
Partial Purification ◽  
Atpase Inhibitor ◽  
Sodium Potassium ◽  
Hypothalamic Cells ◽  
Potassium Atpase

scholarly journals Butyrate Prevents TGF-β1-Induced Alveolar Myofibroblast Differentiation and Modulates Energy Metabolism

Metabolites ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 258
Author(s):  
Hyo Yeong Lee ◽  
Somi Nam ◽  
Mi Jeong Kim ◽  
Su Jung Kim ◽  
Sung Hoon Back ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Pulmonary Fibrosis ◽  
Transforming Growth Factor ◽  
Mitochondrial Dynamics ◽  
Tca Cycle ◽  
Lung Fibroblasts ◽  
Myofibroblast Differentiation ◽  
Pulmonary Fibroblasts ◽  
Matrix Deposition ◽  
Tgf Β1

Idiopathic pulmonary fibrosis (IPF) is a serious lung disease characterized by excessive collagen matrix deposition and extracellular remodeling. Signaling pathways mediated by fibrotic cytokine transforming growth factor β1 (TGF-β1) make important contributions to pulmonary fibrosis, but it remains unclear how TGF-β1 alters metabolism and modulates the activation and differentiation of pulmonary fibroblasts. We found that TGF-β1 lowers NADH and NADH/NAD levels, possibly due to changes in the TCA cycle, resulting in reductions in the ATP level and oxidative phosphorylation in pulmonary fibroblasts. In addition, we showed that butyrate (C4), a short chain fatty acid (SCFA), exhibits potent antifibrotic activity by inhibiting expression of fibrosis markers. Butyrate treatment inhibited mitochondrial elongation in TGF-β1-treated lung fibroblasts and increased the mitochondrial membrane potential (MMP). Consistent with the mitochondrial observations, butyrate significantly increased ADP, ATP, NADH, and NADH/NAD levels in TGF-β1-treated pulmonary fibroblasts. Collectively, our findings indicate that TGF-β1 induces changes in mitochondrial dynamics and energy metabolism during myofibroblast differentiation, and that these changes can be modulated by butyrate, which enhances mitochondrial function.

scholarly journals Metabolomic Analysis to Elucidate Mechanisms of Sunitinib Resistance in Renal Cell Carcinoma

Metabolites ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 1
Author(s):  
Tomonori Sato ◽  
Yoshihide Kawasaki ◽  
Masamitsu Maekawa ◽  
Shinya Takasaki ◽  
Kento Morozumi ◽  
...  
Keyword(s):  
Renal Cell Carcinoma ◽  
Energy Metabolism ◽  
Cell Carcinoma ◽  
Cell Line ◽  
Cell Lines ◽  
Cancer Progression ◽  
Renal Cell ◽  
Treatment Resistance ◽  
Tca Cycle ◽  
Glutamine Uptake

Metabolomics analysis possibly identifies new therapeutic targets in treatment resistance by measuring changes in metabolites accompanying cancer progression. We previously conducted a global metabolomics (G-Met) study of renal cell carcinoma (RCC) and identified metabolites that may be involved in sunitinib resistance in RCC. Here, we aimed to elucidate possible mechanisms of sunitinib resistance in RCC through intracellular metabolites. We established sunitinib-resistant and control RCC cell lines from tumor tissues of RCC cell (786-O)-injected mice. We also quantified characteristic metabolites identified in our G-Met study to compare intracellular metabolism between the two cell lines using liquid chromatography-mass spectrometry. The established sunitinib-resistant RCC cell line demonstrated significantly desuppressed protein kinase B (Akt) and mesenchymal-to-epithelial transition (MET) phosphorylation compared with the control RCC cell line under sunitinib exposure. Among identified metabolites, glutamine, glutamic acid, and α-KG (involved in glutamine uptake into the tricarboxylic acid (TCA) cycle for energy metabolism); fructose 6-phosphate, D-sedoheptulose 7-phosphate, and glucose 1-phosphate (involved in increased glycolysis and its intermediate metabolites); and glutathione and myoinositol (antioxidant effects) were significantly increased in the sunitinib-resistant RCC cell line. Particularly, glutamine transporter (SLC1A5) expression was significantly increased in sunitinib-resistant RCC cells compared with control cells. In this study, we demonstrated energy metabolism with glutamine uptake and glycolysis upregulation, as well as antioxidant activity, was also associated with sunitinib resistance in RCC cells.

Fatty acid, tricarboxylic acid cycle metabolites, and energy metabolism in vascular smooth muscle

1994 ◽  
Vol 267 (2) ◽  
pp. H764-H769 ◽  
Author(s):  
J. T. Barron ◽  
S. J. Kopp ◽  
J. Tow ◽  
J. E. Parrillo
Keyword(s):  
Smooth Muscle ◽  
Fatty Acid ◽  
Energy Metabolism ◽  
Carotid Artery ◽  
Vascular Smooth Muscle ◽  
Lactate Production ◽  
Tca Cycle ◽  
High Energy ◽  
Tricarboxylic Acid ◽  
O2 Consumption

The influence of octanoate on O2 consumption, tricarboxylic acid (TCA) cycle intermediates, and high-energy phosphates was examined in intact resting porcine carotid artery to investigate the role of fatty acid in energy metabolism and its integration with glucose metabolism in vascular smooth muscle. Incubation of resting arteries with octanoate (0.5 mM), which was previously shown to inhibit aerobic glycolysis (6), inhibited lactate production by 64% and increased O2 consumption by 30%. The increase in O2 consumption with octanoate was approximately equal to that calculated to account for the ATP production lost by inhibition of aerobic lactate production by octanoate. In glucose-free medium, the level of high-energy phosphate was reduced but was restored when octanoate was included in the incubation medium. This was associated with an increase in O2 consumption. These results suggest that the energy requirements of resting carotid artery can be largely met by the oxidative metabolism of fatty acid. Octanoate induced anaplerosis of the TCA cycle, as indicated by a 70% increase in the level of citrate. Extracellular glucose was necessary for octanoate-induced anaplerosis, probably by providing the extra carbon via pyruvate carboxylation, whereas a coupled transamination involving aspartate was a less important anaplerotic mechanism.

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