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Liu B, Zhong Y, Huang D, Yang L, Wang P, Yang L, Zhang F, Li X, Liang M, Huang K, Du M. LncRNA Nron deficiency protects mice from diet-induced adiposity and hepatic steatosis. Metabolism 2023; 148:155609. [PMID: 37277059 DOI: 10.1016/j.metabol.2023.155609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 04/27/2023] [Accepted: 05/30/2023] [Indexed: 06/07/2023]
Abstract
Obesity, as a worldwide healthcare problem, has attracted more and more attention. Here we identify a long non-coding RNA NRON, which is highly conserved across species, as an important regulator of glucose/lipid metabolism and whole-body energy expenditure. Depletion of Nron leads to metabolic benefits in DIO (diet-induced obesity) mice, including reduced body weight and fat mass, improved insulin sensitivity and serum lipid parameters, attenuated hepatic steatosis and enhanced adipose function. Mechanistically, Nron deletion improves hepatic lipid homeostasis via PER2/Rev-Erbα/FGF21 axis coupled with AMPK activation, and enhances adipose function via activating the process of triacylglycerol hydrolysis and fatty acid re-esterification (TAG/FA cycling) and coupled metabolic network. These interactive and integrative effects cooperatively account for a healthier metabolic phenotype in NKO (Nron knockout) mice. Genetic or pharmacological inhibition of Nron may have potential for future therapy of obesity.
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Affiliation(s)
- Bing Liu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Yi Zhong
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dandan Huang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Liuye Yang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Pengchao Wang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Liu Yang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Metabolic Abnormalities and Vascular Aging, Huazhong University of Science and Technology, Wuhan, China; Hubei Clinical Research Center of Metabolic and Cardiovascular Disease, Huazhong University of Science and Technology, Wuhan, China
| | - Fengxiao Zhang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Metabolic Abnormalities and Vascular Aging, Huazhong University of Science and Technology, Wuhan, China; Hubei Clinical Research Center of Metabolic and Cardiovascular Disease, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoguang Li
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Metabolic Abnormalities and Vascular Aging, Huazhong University of Science and Technology, Wuhan, China; Hubei Clinical Research Center of Metabolic and Cardiovascular Disease, Huazhong University of Science and Technology, Wuhan, China
| | - Minglu Liang
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Metabolic Abnormalities and Vascular Aging, Huazhong University of Science and Technology, Wuhan, China; Hubei Clinical Research Center of Metabolic and Cardiovascular Disease, Huazhong University of Science and Technology, Wuhan, China
| | - Kai Huang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Metabolic Abnormalities and Vascular Aging, Huazhong University of Science and Technology, Wuhan, China; Hubei Clinical Research Center of Metabolic and Cardiovascular Disease, Huazhong University of Science and Technology, Wuhan, China.
| | - Meng Du
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Metabolic Abnormalities and Vascular Aging, Huazhong University of Science and Technology, Wuhan, China; Hubei Clinical Research Center of Metabolic and Cardiovascular Disease, Huazhong University of Science and Technology, Wuhan, China.
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Talarico GGM, Thoral E, Farhat E, Teulier L, Mennigen JA, Weber JM. Lactate signaling and fuel selection in rainbow trout: mobilization of energy reserves. Am J Physiol Regul Integr Comp Physiol 2023; 325:R556-R567. [PMID: 37694336 DOI: 10.1152/ajpregu.00033.2023] [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: 02/06/2023] [Revised: 08/15/2023] [Accepted: 09/06/2023] [Indexed: 09/12/2023]
Abstract
Lactate is now recognized as a regulator of fuel selection in mammals because it inhibits lipolysis by binding to the hydroxycarboxylic acid receptor 1 (HCAR1). The goals of this study were to quantify the effects of exogenous lactate on: 1) lipolytic rate or rate of appearance of glycerol in the circulation (Ra glycerol) and hepatic glucose production (Ra glucose), and 2) key tissue proteins involved in lactate signaling, glucose transport, glycolysis, gluconeogenesis, lipolysis, and β-oxidation in rainbow trout. Measurements of fuel mobilization kinetics show that lactate does not affect lipolysis as it does in mammals (Ra glycerol remains at 7.3 ± 0.5 µmol·kg-1·min-1), but strongly reduces hepatic glucose production (16.4 ± 2.0 to 8.9 ± 1.2 µmol·kg-1·min-1). This reduction is likely induced by decreasing gluconeogenic flux through the inhibition of cytosolic phosphoenolpyruvate carboxykinase (Pck1, alternatively called Pepck1; 60% and 24% declines in gene expression and protein level, respectively). It is also caused by lactate substituting for glucose as a fuel in all tissues except white muscle that increases glut4a expression and has limited capacity for monocarboxylate transporter (Mct)-mediated lactate import. We conclude that lipolysis is not affected by hyperlactatemia because trout show no activation of autocrine Hcar1 signaling (gene expression of the receptor is unchanged or even repressed in red muscle). Lactate regulates fuel mobilization via Pck1-mediated suppression of gluconeogenesis and by replacing glucose as a fuel. This study highlights important functional differences in the Hcar1 signaling system between fish and mammals for the regulation of fuel selection.
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Affiliation(s)
| | - Elisa Thoral
- Biology Department, University of Ottawa, Ottawa, Ontario, Canada
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique, École Nationale des Travaux Publics de l'État, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés, Villeurbanne, France
| | - Elie Farhat
- Biology Department, University of Ottawa, Ottawa, Ontario, Canada
| | - Loïc Teulier
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique, École Nationale des Travaux Publics de l'État, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés, Villeurbanne, France
| | - Jan A Mennigen
- Biology Department, University of Ottawa, Ottawa, Ontario, Canada
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Turenne ED, Weber JM. Lean, mean, lipolytic machines: lipid mobilization in rainbow trout during graded swimming. ACTA ACUST UNITED AC 2018; 221:jeb.171553. [PMID: 29212842 DOI: 10.1242/jeb.171553] [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: 10/03/2017] [Accepted: 11/28/2017] [Indexed: 11/20/2022]
Abstract
The mobilization of mammalian lipid reserves is strongly stimulated during exercise to reach a maximum at moderate intensities, but the effects of swimming speed on fish lipolysis have never been quantified. Continuous infusion of 2-[3H]glycerol was used to measure the rate of appearance of glycerol or lipolytic rate (Ra glycerol) in rainbow trout kept at rest, or during graded exercise in a swim tunnel up to critical swimming speed (Ucrit). Results show that Ra glycerol is 1.67±0.18 µmol kg-1 min-1 in control animals, and remains at a steady level of 1.24±0.10 µmol kg-1 min-1 in exercising fish at all swimming intensities. Baseline lipolytic rate provides more than enough fatty acids from lipid reserves to accommodate all the oxidative fuel requirements for swimming at up to 2 body lengths per second (BL s-1), and more than 50% of the energy needed at Ucrit (3.4±0.1 BL s-1). Such 'excess lipolysis' also means that trout sustain high rates of fatty acid reesterification. Maintaining steady lipolysis at rest and throughout graded swimming is strikingly different from mammals that stimulate Ra glycerol by twofold to fivefold to support exercise. Instead, trout act like 'lipolytic machines' that do not modulate Ra glycerol even when their metabolic rate triples - a strategy that eliminates the need to increase lipolytic rate during exercise. This study also supports the notion that maintaining a high rate of reesterification (or triacylglycerol/fatty acid cycling) may be a mechanism widely used by ectotherms to achieve rapid membrane remodelling in variable environments.
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Affiliation(s)
- Eric D Turenne
- Biology Department, University of Ottawa, Ottawa, Ontario, Canada, K1N 6N5
| | - Jean-Michel Weber
- Biology Department, University of Ottawa, Ottawa, Ontario, Canada, K1N 6N5
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Fowler MA, Costa DP, Crocker DE, Shen WJ, Kraemer FB. Adipose Triglyceride Lipase, Not Hormone-Sensitive Lipase, Is the Primary Lipolytic Enzyme in Fasting Elephant Seals (Mirounga angustirostris). Physiol Biochem Zool 2015; 88:284-94. [PMID: 25860827 DOI: 10.1086/680079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Little is known about the mechanisms that allow capital breeders to rapidly mobilize large amounts of body reserves. Northern elephant seals (Mirounga angustirostris) utilize fat reserves for maternal metabolism and to create high fat milk for the pup. Hormone-sensitive lipase (HSL) has been hypothesized to be an important lipolytic enzyme in fasting seals, but the activity of HSL and adipose triglyceride lipase (ATGL) has not been quantified in fasting adult seals, nor has their relationship to milk lipid content been assessed. Blubber and milk samples were obtained from 18 early lactation and 19 late lactation females, as well as blubber from five early and five late molting female seals. Blubber lipolytic activity was assessed with radiometric assays. HSL activity was negligible in seal blubber at all fasting stages. Total triglyceride lipase activity was stable among early and late lactation and early molt but increased in late molting seals. Relative abundance of ATGL protein increased across fasting, but neither activity nor relative protein levels were related to circulating nonesterified fatty acids or milk lipid content, suggesting the possibility of other regulatory pathways between lipolytic activity and milk lipid content. These results demonstrate that HSL is not the primary lipolytic enzyme in fasting adult female seals and that ATGL contributes more to lipolysis than HSL.
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Affiliation(s)
- Melinda A Fowler
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California; 2Department of Biology, Sonoma State University, Rohnert Park, California; 3Division of Endocrinology, Gerontology, and Metabolism, Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, California
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Hanssen MJW, Wierts R, Hoeks J, Gemmink A, Brans B, Mottaghy FM, Schrauwen P, van Marken Lichtenbelt WD. Glucose uptake in human brown adipose tissue is impaired upon fasting-induced insulin resistance. Diabetologia 2015; 58:586-95. [PMID: 25500952 DOI: 10.1007/s00125-014-3465-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 11/17/2014] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Human brown adipose tissue (BAT) has recently emerged as a potential target in the treatment of type 2 diabetes, owing to its capacity to actively clear glucose from the circulation—at least upon cold exposure. The effects of insulin resistance on the capacity of human BAT to take up glucose are unknown. Prolonged fasting is known to induce insulin resistance in peripheral tissues in order to spare glucose for the brain. METHODS We studied the effect of fasting-induced insulin resistance on the capacity of BAT to take up glucose during cold exposure as well as on cold-stimulated thermogenesis. BAT glucose uptake was assessed by means of cold-stimulated dynamic 2-deoxy-2-[(18)F]fluoro-D-glucose positron emission tomography/computed tomography ([(18)F]FDG-PET/CT) imaging. RESULTS We show that a 54 h fasting period markedly decreases both cold-induced BAT glucose uptake and nonshivering thermogenesis (NST) during cold stimulation. In vivo molecular imaging and modelling revealed that the reduction of glucose uptake in BAT was due to impaired cellular glucose uptake and not due to decreased supply. Interestingly, decreased BAT glucose uptake upon fasting was related to a decrease in core temperature during cold exposure, pointing towards a role for BAT in maintaining normothermia in humans. CONCLUSIONS/INTERPRETATION Cold-stimulated glucose uptake in BAT is strongly reduced upon prolonged fasting. When cold-stimulated glucose uptake in BAT is also reduced under other insulin-resistant states, such as diabetes, cold-induced activation of BAT may not be a valid way to improve glucose clearance by BAT under such conditions. TRIAL REGISTRATION www.trialregister.nl NTR3523 FUNDING: This work was supported by the EU FP7 project DIABAT (HEALTH-F2-2011-278373 to WDvML) and by the Netherlands Organization for Scientific Research (TOP 91209037 to WDvML).
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Affiliation(s)
- Mark J W Hanssen
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre+ (MUMC+), P.O. Box 616, 6200 MD, Maastricht, the Netherlands
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Sherwani SI, Aldana C, Usmani S, Adin C, Kotha S, Khan M, Eubank T, Scherer PE, Parinandi N, Magalang UJ. Intermittent hypoxia exacerbates pancreatic β-cell dysfunction in a mouse model of diabetes mellitus. Sleep 2013; 36:1849-58. [PMID: 24293759 DOI: 10.5665/sleep.3214] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
STUDY OBJECTIVES The effects of intermittent hypoxia (IH) on pancreatic function in the presence of diabetes and the underlying mechanisms are unclear. We hypothesized that IH would exacerbate pancreatic β-cell dysfunction and alter the fatty acids in the male Tallyho/JngJ (TH) mouse, a rodent model of type 2 diabetes. DESIGN TH mice were exposed for 14 d to either 8 h of IH or intermittent air (IA), followed by an intraperitoneal glucose tolerance test (IPGTT) and tissue harvest. The effect of IH on insulin release was determined by using a β3-adrenergic receptor (AR) agonist. MEASUREMENTS AND RESULTS During IH, pancreatic tissue pO2 decreased from 20.4 ± 0.9 to 5.7 ± 2.6 mm Hg, as determined by electron paramagnetic resonance oximetry. TH mice exposed to IH exhibited higher plasma glucose levels during the IPGTT (P < 0.001) while the insulin levels tended to be lower (P = 0.06). Pancreatic islets of the IH group showed an enhancement of the caspase-3 staining (P = 0.002). IH impaired the β-AR agonist-mediated insulin release (P < 0.001). IH increased the levels of the total free fatty acids and saturated fatty acids (palmitic and stearic acids), and decreased levels of the monounsaturated fatty acids in the pancreas and plasma. Ex vivo exposure of pancreatic islets to palmitic acid suppressed insulin secretion and decreased islet cell viability. CONCLUSIONS Intermittent hypoxia increases pancreatic apoptosis and exacerbates dysfunction in a polygenic rodent model of diabetes. An increase in free fatty acids and a shift in composition towards long chain saturated fatty acid species appear to mediate these effects.
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Affiliation(s)
- Shariq I Sherwani
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Wexner Medical Center, The Ohio State University, Columbus, OH ; Dorothy M. Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH
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