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Zhang Y, Bock F, Ferdaus M, Arroyo JP, L Rose K, Patel P, Denton JS, Delpire E, Weinstein AM, Zhang MZ, Harris RC, Terker AS. Low potassium activation of proximal mTOR/AKT signaling is mediated by Kir4.2. Nat Commun 2024; 15:5144. [PMID: 38886379 PMCID: PMC11183202 DOI: 10.1038/s41467-024-49562-w] [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: 08/31/2023] [Accepted: 06/07/2024] [Indexed: 06/20/2024] Open
Abstract
The renal epithelium is sensitive to changes in blood potassium (K+). We identify the basolateral K+ channel, Kir4.2, as a mediator of the proximal tubule response to K+ deficiency. Mice lacking Kir4.2 have a compensated baseline phenotype whereby they increase their distal transport burden to maintain homeostasis. Upon dietary K+ depletion, knockout animals decompensate as evidenced by increased urinary K+ excretion and development of a proximal renal tubular acidosis. Potassium wasting is not proximal in origin but is caused by higher ENaC activity and depends upon increased distal sodium delivery. Three-dimensional imaging reveals Kir4.2 knockouts fail to undergo proximal tubule expansion, while the distal convoluted tubule response is exaggerated. AKT signaling mediates the dietary K+ response, which is blunted in Kir4.2 knockouts. Lastly, we demonstrate in isolated tubules that AKT phosphorylation in response to low K+ depends upon mTORC2 activation by secondary changes in Cl- transport. Data support a proximal role for cell Cl- which, as it does along the distal nephron, responds to K+ changes to activate kinase signaling.
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Affiliation(s)
- Yahua Zhang
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
| | - Fabian Bock
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
| | - Mohammed Ferdaus
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Juan Pablo Arroyo
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
| | - Kristie L Rose
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
- Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Purvi Patel
- Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jerod S Denton
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alan M Weinstein
- Department of Physiology and Biophysics, Weil Medical College, New York, NY, USA
| | - Ming-Zhi Zhang
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
| | - Raymond C Harris
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA
| | - Andrew S Terker
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA.
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2
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Martino MR, Habibi M, Ferguson D, Brookheart RT, Thyfault JP, Meyer GA, Lantier L, Hughey CC, Finck BN. Disruption of hepatic mitochondrial pyruvate and amino acid metabolism impairs gluconeogenesis and endurance exercise capacity in mice. Am J Physiol Endocrinol Metab 2024; 326:E515-E527. [PMID: 38353639 PMCID: PMC11193532 DOI: 10.1152/ajpendo.00258.2023] [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: 08/16/2023] [Revised: 01/25/2024] [Accepted: 02/08/2024] [Indexed: 02/23/2024]
Abstract
Exercise robustly increases the glucose demands of skeletal muscle. This demand is met by not only muscle glycogenolysis but also accelerated liver glucose production from hepatic glycogenolysis and gluconeogenesis to fuel mechanical work and prevent hypoglycemia during exercise. Hepatic gluconeogenesis during exercise is dependent on highly coordinated responses within and between muscle and liver. Specifically, exercise increases the rate at which gluconeogenic precursors such as pyruvate/lactate or amino acids are delivered from muscle to the liver, extracted by the liver, and channeled into glucose. Herein, we examined the effects of interrupting hepatic gluconeogenic efficiency and capacity on exercise performance by deleting mitochondrial pyruvate carrier 2 (MPC2) and/or alanine transaminase 2 (ALT2) in the liver of mice. We found that deletion of MPC2 or ALT2 alone did not significantly affect time to exhaustion or postexercise glucose concentrations in treadmill exercise tests, but mice lacking both MPC2 and ALT2 in hepatocytes (double knockout, DKO) reached exhaustion faster and exhibited lower circulating glucose during and after exercise. Use of 2H/1³C metabolic flux analyses demonstrated that DKO mice exhibited lower endogenous glucose production owing to decreased glycogenolysis and gluconeogenesis at rest and during exercise. Decreased gluconeogenesis was accompanied by lower anaplerotic, cataplerotic, and TCA cycle fluxes. Collectively, these findings demonstrate that the transition of the liver to the gluconeogenic mode is critical for preventing hypoglycemia and sustaining performance during exercise. The results also illustrate the need for interorgan cross talk during exercise as described by the Cahill and Cori cycles.NEW & NOTEWORTHY Martino and colleagues examined the effects of inhibiting hepatic gluconeogenesis on exercise performance and systemic metabolism during treadmill exercise in mice. Combined inhibition of gluconeogenesis from lactate/pyruvate and alanine impaired exercise endurance and led to hypoglycemia during and after exercise. In contrast, suppressing either pyruvate-mediated or alanine-mediated gluconeogenesis alone had no effect on these parameters. These findings provide new insight into the molecular nodes that coordinate the metabolic responses of muscle and liver during exercise.
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Affiliation(s)
- Michael R Martino
- Division of Nutritional Sciences and Obesity Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Mohammad Habibi
- Division of Nutritional Sciences and Obesity Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Daniel Ferguson
- Division of Nutritional Sciences and Obesity Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Rita T Brookheart
- Division of Nutritional Sciences and Obesity Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
| | - John P Thyfault
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, Missouri, United States
| | - Gretchen A Meyer
- Department of Medicine, Program in Physical Therapy, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Louise Lantier
- Department of Molecular Physiology and Biophysics, Vanderbilt Mouse Metabolic Phenotyping Center, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Curtis C Hughey
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States
| | - Brian N Finck
- Division of Nutritional Sciences and Obesity Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
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3
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Shibao C, Peche VS, Williams IM, Samovski D, Pietka TA, Abumrad NN, Gamazon E, Goldberg IJ, Wasserman D, Abumrad NA. Microvascular insulin resistance associates with enhanced muscle glucose disposal in CD36 deficiency. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.02.16.24302950. [PMID: 38405702 PMCID: PMC10889024 DOI: 10.1101/2024.02.16.24302950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Dysfunction of endothelial insulin delivery to muscle associates with insulin resistance. CD36, a fatty acid transporter and modulator of insulin signaling is abundant in endothelial cells, especially in capillaries. Humans with inherited 50% reduction in CD36 expression have endothelial dysfunction but whether it is associated with insulin resistance is unclear. Using hyperinsulinemic/euglycemic clamps in Cd36-/- and wildtype mice, and in 50% CD36 deficient humans and matched controls we found that Cd36-/- mice have enhanced systemic glucose disposal despite unaltered transendothelial insulin transfer and reductions in microvascular perfusion and blood vessel compliance. Partially CD36 deficient humans also have better glucose disposal than controls with no capillary recruitment by insulin. CD36 knockdown in primary human-derived microvascular cells impairs insulin action on AKT, endothelial nitric oxide synthase, and nitric oxide release. Thus, insulin resistance of microvascular function in CD36 deficiency paradoxically associates with increased glucose utilization, likely through a remodeling of muscle gene expression.
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Affiliation(s)
- Cyndya Shibao
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville TN
| | - Vivek S. Peche
- Department of Medicine, Division of Nutritional Sciences and Obesity Research, Washington University School of Medicine, St. Louis, MO
| | - Ian M. Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville TN
| | - Dmitri Samovski
- Department of Medicine, Division of Nutritional Sciences and Obesity Research, Washington University School of Medicine, St. Louis, MO
| | - Terri A. Pietka
- Department of Medicine, Division of Nutritional Sciences and Obesity Research, Washington University School of Medicine, St. Louis, MO
| | - Naji N. Abumrad
- Department of Surgery, Vanderbilt University Medical Center, Nashville TN
| | - Eric Gamazon
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University, Nashville, TN
| | - Ira J. Goldberg
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, New York University Grossman School of Medicine, New York, NY
| | - David Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville TN
| | - Nada A. Abumrad
- Department of Medicine, Division of Nutritional Sciences and Obesity Research, Washington University School of Medicine, St. Louis, MO
- Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, MO
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4
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Ceddia RP, Zurawski Z, Thompson Gray A, Adegboye F, McDonald-Boyer A, Shi F, Liu D, Maldonado J, Feng J, Li Y, Alford S, Ayala JE, McGuinness OP, Collins S, Hamm HE. Gβγ-SNAP25 exocytotic brake removal enhances insulin action, promotes adipocyte browning, and protects against diet-induced obesity. J Clin Invest 2023; 133:e160617. [PMID: 37561580 PMCID: PMC10541194 DOI: 10.1172/jci160617] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 08/08/2023] [Indexed: 08/12/2023] Open
Abstract
Negative regulation of exocytosis from secretory cells is accomplished through inhibitory signals from Gi/o GPCRs by Gβγ subunit inhibition of 2 mechanisms: decreased calcium entry and direct interaction of Gβγ with soluble N-ethylmaleimide-sensitive factor attachment protein (SNAP) receptor (SNARE) plasma membrane fusion machinery. Previously, we disabled the second mechanism with a SNAP25 truncation (SNAP25Δ3) that decreased Gβγ affinity for the SNARE complex, leaving exocytotic fusion and modulation of calcium entry intact and removing GPCR-Gβγ inhibition of SNARE-mediated exocytosis. Here, we report substantial metabolic benefit in mice carrying this mutation. Snap25Δ3/Δ3 mice exhibited enhanced insulin sensitivity and beiging of white fat. Metabolic protection was amplified in Snap25Δ3/Δ3 mice challenged with a high-fat diet. Glucose homeostasis, whole-body insulin action, and insulin-mediated glucose uptake into white adipose tissue were improved along with resistance to diet-induced obesity. Metabolic protection in Snap25Δ3/Δ3 mice occurred without compromising the physiological response to fasting or cold. All metabolic phenotypes were reversed at thermoneutrality, suggesting that basal autonomic activity was required. Direct electrode stimulation of sympathetic neuron exocytosis from Snap25Δ3/Δ3 inguinal adipose depots resulted in enhanced and prolonged norepinephrine release. Thus, the Gβγ-SNARE interaction represents a cellular mechanism that deserves further exploration as an additional avenue for combating metabolic disease.
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Affiliation(s)
- Ryan P. Ceddia
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Zack Zurawski
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois, USA
| | | | - Feyisayo Adegboye
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Fubiao Shi
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Dianxin Liu
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jose Maldonado
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Jiesi Feng
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Chinese Institute for Brain Research, Beijing, China
| | - Simon Alford
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Julio E. Ayala
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Owen P. McGuinness
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Sheila Collins
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Heidi E. Hamm
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
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5
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Tixi W, Maldonado M, Chang YT, Chiu A, Yeung W, Parveen N, Nelson MS, Hart R, Wang S, Hsu WJ, Fueger P, Kopp JL, Huising MO, Dhawan S, Shih HP. Coordination between ECM and cell-cell adhesion regulates the development of islet aggregation, architecture, and functional maturation. eLife 2023; 12:e90006. [PMID: 37610090 PMCID: PMC10482429 DOI: 10.7554/elife.90006] [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: 06/07/2023] [Accepted: 07/12/2023] [Indexed: 08/24/2023] Open
Abstract
Pancreatic islets are three-dimensional cell aggregates consisting of unique cellular composition, cell-to-cell contacts, and interactions with blood vessels. Cell aggregation is essential for islet endocrine function; however, it remains unclear how developing islets establish aggregation. By combining genetic animal models, imaging tools, and gene expression profiling, we demonstrate that islet aggregation is regulated by extracellular matrix signaling and cell-cell adhesion. Islet endocrine cell-specific inactivation of extracellular matrix receptor integrin β1 disrupted blood vessel interactions but promoted cell-cell adhesion and the formation of larger islets. In contrast, ablation of cell-cell adhesion molecule α-catenin promoted blood vessel interactions yet compromised islet clustering. Simultaneous removal of integrin β1 and α-catenin disrupts islet aggregation and the endocrine cell maturation process, demonstrating that establishment of islet aggregates is essential for functional maturation. Our study provides new insights into understanding the fundamental self-organizing mechanism for islet aggregation, architecture, and functional maturation.
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Affiliation(s)
- Wilma Tixi
- Department of Translational Research and Cellular Therapeutics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of HopeDuarteUnited States
| | - Maricela Maldonado
- Department of Translational Research and Cellular Therapeutics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of HopeDuarteUnited States
- Department of Biomedical Engineering, College of Engineering, California State University, Long BeachLong BeachUnited States
| | - Ya-Ting Chang
- Department of Translational Research and Cellular Therapeutics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of HopeDuarteUnited States
| | - Amy Chiu
- Department of Translational Research and Cellular Therapeutics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of HopeDuarteUnited States
| | - Wilson Yeung
- Department of Translational Research and Cellular Therapeutics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of HopeDuarteUnited States
| | - Nazia Parveen
- Department of Translational Research and Cellular Therapeutics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of HopeDuarteUnited States
| | - Michael S Nelson
- Light Microscopy Core, Beckman Research Institute, City of HopeDuarteUnited States
| | - Ryan Hart
- Department of Neurobiology, Physiology and Behavior, University of California, DavisDavisUnited States
| | - Shihao Wang
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British ColumbiaVancouverCanada
| | - Wu Jih Hsu
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British ColumbiaVancouverCanada
| | - Patrick Fueger
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of HopeDuarteUnited States
| | - Janel L Kopp
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British ColumbiaVancouverCanada
| | - Mark O Huising
- Department of Neurobiology, Physiology and Behavior, University of California, DavisDavisUnited States
- Department of Physiology and Membrane Biology, School of Medicine, University of California, DavisDavisUnited States
| | - Sangeeta Dhawan
- Department of Translational Research and Cellular Therapeutics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of HopeDuarteUnited States
| | - Hung Ping Shih
- Department of Translational Research and Cellular Therapeutics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of HopeDuarteUnited States
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6
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Adams MT, Waters BJ, Nimkulrat SD, Blum B. Disrupted glucose homeostasis and glucagon and insulin secretion defects in Robo βKO mice. FASEB J 2023; 37:e23106. [PMID: 37498234 PMCID: PMC10436995 DOI: 10.1096/fj.202200705rr] [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: 05/17/2022] [Revised: 07/05/2023] [Accepted: 07/10/2023] [Indexed: 07/28/2023]
Abstract
The axon guidance proteins, Roundabout (Robo) receptors play a critical role in morphogenesis of the islets of Langerhans. Mice with a β cell-selective deletion of Robo (Robo βKO), show severely disrupted spatial architecture of their islets, without defects in β cell differentiation or maturity. We have recently shown that Robo βKO mice have reduced synchronous glucose-stimulated β cell calcium oscillations in their islets in vivo, likely disrupting their pulsatile insulin secretion. Here, we analyze whole-body metabolic regulation in Robo βKO mice. We show that Robo βKO mice have mild defects in glucose homeostasis, and altered glucagon and insulin secretion. However, we did not observe any severe whole-body glucoregulatory phenotype following the disruption of islet architecture in Robo βKO. Our data suggest that islet architecture plays only a mild role in overall glucoregulation.
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Affiliation(s)
- Melissa T. Adams
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Bayley J. Waters
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Sutichot D. Nimkulrat
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Barak Blum
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA
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7
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Rome FI, Shobert GL, Voigt WC, Stagg DB, Puchalska P, Burgess SC, Crawford PA, Hughey CC. Loss of hepatic phosphoenolpyruvate carboxykinase 1 dysregulates metabolic responses to acute exercise but enhances adaptations to exercise training in mice. Am J Physiol Endocrinol Metab 2023; 324:E9-E23. [PMID: 36351254 PMCID: PMC9799143 DOI: 10.1152/ajpendo.00222.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 11/10/2022]
Abstract
Acute exercise increases liver gluconeogenesis to supply glucose to working muscles. Concurrently, elevated liver lipid breakdown fuels the high energetic cost of gluconeogenesis. This functional coupling between liver gluconeogenesis and lipid oxidation has been proposed to underlie the ability of regular exercise to enhance liver mitochondrial oxidative metabolism and decrease liver steatosis in individuals with nonalcoholic fatty liver disease. Herein we tested whether repeated bouts of increased hepatic gluconeogenesis are necessary for exercise training to lower liver lipids. Experiments used diet-induced obese mice lacking hepatic phosphoenolpyruvate carboxykinase 1 (KO) to inhibit gluconeogenesis and wild-type (WT) littermates. 2H/13C metabolic flux analysis quantified glucose and mitochondrial oxidative fluxes in untrained mice at rest and during acute exercise. Circulating and tissue metabolite levels were determined during sedentary conditions, acute exercise, and refeeding postexercise. Mice also underwent 6 wk of treadmill running protocols to define hepatic and extrahepatic adaptations to exercise training. Untrained KO mice were unable to maintain euglycemia during acute exercise resulting from an inability to increase gluconeogenesis. Liver triacylglycerides were elevated after acute exercise and circulating β-hydroxybutyrate was higher during postexercise refeeding in untrained KO mice. In contrast, exercise training prevented liver triacylglyceride accumulation in KO mice. This was accompanied by pronounced increases in indices of skeletal muscle mitochondrial oxidative metabolism in KO mice. Together, these results show that hepatic gluconeogenesis is dispensable for exercise training to reduce liver lipids. This may be due to responses in ketone body metabolism and/or metabolic adaptations in skeletal muscle to exercise.NEW & NOTEWORTHY Exercise training reduces hepatic steatosis partly through enhanced hepatic terminal oxidation. During acute exercise, hepatic gluconeogenesis is elevated to match the heightened rate of muscle glucose uptake and maintain glucose homeostasis. It has been postulated that the hepatic energetic stress induced by elevating gluconeogenesis during acute exercise is a key stimulus underlying the beneficial metabolic responses to exercise training. This study shows that hepatic gluconeogenesis is not necessary for exercise training to lower liver lipids.
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Affiliation(s)
- Ferrol I Rome
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Gregory L Shobert
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - William C Voigt
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - David B Stagg
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota
| | - Patrycja Puchalska
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Shawn C Burgess
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, Texas
| | - Peter A Crawford
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota
| | - Curtis C Hughey
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
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8
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Liu X, Chen L, Hu X. Hyperinsulinemic-Euglycemic Clamp in Conscious Rats Based on the Tail Artery and Vein Catheterization. Methods Mol Biol 2022; 2592:155-161. [PMID: 36507991 DOI: 10.1007/978-1-0716-2807-2_10] [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: 12/14/2022]
Abstract
Insulin sensitivity evaluation is very important in the management and investigation of type 1 diabetes. Hyperinsulinemic-euglycemic clamp (HEC) is considered to be the "gold standard" method for the assessment of insulin sensitivity in vivo. Here, we describe the method of performing the hyperinsulinemic-glycemic clamp based on the tail artery and vein catheterization after administration of local anesthesia to the tail root in conscious rats. Insulin and glucose were infused via the tail vein, and blood samples for further determination were collected from the tail artery. This procedure makes the hyperinsulinemic-euglycemic clamp easier and more convenient to perform.
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Affiliation(s)
- Xiaohuan Liu
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China
| | - LuLu Chen
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
- Hubei provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China.
| | - Xiang Hu
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
- Hubei provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China.
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9
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Tadinada SM, Grzesik WJ, Kutschke W, Weiss RM, Abel ED. Acute effects of euglycemic-hyperinsulinemia on myocardial contractility in male mice. Physiol Rep 2022; 10:e15388. [PMID: 36073057 PMCID: PMC9453172 DOI: 10.14814/phy2.15388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 06/19/2022] [Accepted: 06/24/2022] [Indexed: 06/15/2023] Open
Abstract
Type 2 diabetes and obesity are associated with increased risk of cardiovascular disease, including heart failure. A hallmark of these dysmetabolic states is hyperinsulinemia and decreased cardiac reserve. However, the direct effects of hyperinsulinemia on myocardial function are incompletely understood. In this study, using invasive hemodynamics in mice, we studied the effects of short-term euglycemic hyperinsulinemia on basal myocardial function and subsequent responses of the myocardium to β-adrenergic stimulation. We found that cardiac function as measured by left ventricular (LV) invasive hemodynamics is not influenced by acute exposure to hyperinsulinemia, induced by an intravenous insulin injection with concurrent inotropic stimulation induced by β-adrenergic stimulation secondary to isoproterenol administration. When animals were exposed to 120-min of hyperinsulinemia by euglycemic-hyperinsulinemic clamps, there was a significant decrease in LV developed pressure, perhaps secondary to the systemic vasodilatory effects of insulin. Despite the baseline reduction, the contractile response to β-adrenergic stimulation remained intact in animals subject to euglycemic hyperinsulinemic clamps. β-adrenergic activation of phospholamban phosphorylation was not impaired by hyperinsulinemia. These results suggest that short-term hyperinsulinemia does not impair cardiac inotropic response to β-adrenergic stimulation in vivo.
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Affiliation(s)
- Satya Murthy Tadinada
- Department of Neuroscience and Pharmacology, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
- Fraternal Order of Eagles Diabetes Research Center, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
| | - Wojciech J. Grzesik
- Fraternal Order of Eagles Diabetes Research Center, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
| | - William Kutschke
- Abboud Cardiovascular Research Center, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
| | - Robert M. Weiss
- Abboud Cardiovascular Research Center, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
- Division of Cardiology, Department of Internal Medicine, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
| | - E. Dale Abel
- Department of Neuroscience and Pharmacology, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
- Fraternal Order of Eagles Diabetes Research Center, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
- Abboud Cardiovascular Research Center, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
- Department of MedicineUniversity of California Los AngelesLos AngelesCaliforniaUSA
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10
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Cao S, Pan Y, Tang J, Terker AS, Arroyo Ornelas JP, Jin GN, Wang Y, Niu A, Fan X, Wang S, Harris RC, Zhang MZ. EGFR-mediated activation of adipose tissue macrophages promotes obesity and insulin resistance. Nat Commun 2022; 13:4684. [PMID: 35948530 PMCID: PMC9365849 DOI: 10.1038/s41467-022-32348-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 07/26/2022] [Indexed: 12/20/2022] Open
Abstract
Obesity and obesity-related health complications are increasing in prevalence. Adipose tissue from obese subjects has low-grade, chronic inflammation, leading to insulin resistance. Adipose tissue macrophages (ATMs) are a source of proinflammatory cytokines that further aggravate adipocyte dysfunction. In response to a high fat diet (HFD), ATM numbers initially increase by proliferation of resident macrophages, but subsequent increases also result from infiltration in response to chemotactic signals from inflamed adipose tissue. To elucidate the underlying mechanisms regulating the increases in ATMs and their proinflammatory phenotype, we investigated the role of activation of ATM epidermal growth factor receptor (EGFR). A high fat diet increased expression of EGFR and its ligand amphiregulin in ATMs. Selective deletion of EGFR in ATMs inhibited both resident ATM proliferation and monocyte infiltration into adipose tissue and decreased obesity and development of insulin resistance. Therefore, ATM EGFR activation plays an important role in adipose tissue dysfunction.
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Affiliation(s)
- Shirong Cao
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yu Pan
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
- Division of Nephrology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jiaqi Tang
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Andrew S Terker
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Juan Pablo Arroyo Ornelas
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Guan-Nan Jin
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yinqiu Wang
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Aolei Niu
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Xiaofeng Fan
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Suwan Wang
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Raymond C Harris
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA.
- Veterans Affairs, Nashville, TN, USA.
| | - Ming-Zhi Zhang
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA.
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11
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Pan Y, Cao S, Tang J, Arroyo JP, Terker AS, Wang Y, Niu A, Fan X, Wang S, Zhang Y, Jiang M, Wasserman DH, Zhang MZ, Harris RC. Cyclooxygenase-2 in adipose tissue macrophages limits adipose tissue dysfunction in obese mice. J Clin Invest 2022; 132:152391. [PMID: 35499079 PMCID: PMC9057601 DOI: 10.1172/jci152391] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 03/08/2022] [Indexed: 12/25/2022] Open
Affiliation(s)
- Yu Pan
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Division of Nephrology, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shirong Cao
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jiaqi Tang
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Juan P. Arroyo
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Andrew S. Terker
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Yinqiu Wang
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Aolei Niu
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Xiaofeng Fan
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Suwan Wang
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Yahua Zhang
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Ming Jiang
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | | | - Ming-Zhi Zhang
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Raymond C. Harris
- Division of Nephrology and Hypertension, Department of Medicine and
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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12
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Gunasekar SK, Xie L, Kumar A, Hong J, Chheda PR, Kang C, Kern DM, My-Ta C, Maurer J, Heebink J, Gerber EE, Grzesik WJ, Elliot-Hudson M, Zhang Y, Key P, Kulkarni CA, Beals JW, Smith GI, Samuel I, Smith JK, Nau P, Imai Y, Sheldon RD, Taylor EB, Lerner DJ, Norris AW, Klein S, Brohawn SG, Kerns R, Sah R. Small molecule SWELL1 complex induction improves glycemic control and nonalcoholic fatty liver disease in murine Type 2 diabetes. Nat Commun 2022; 13:784. [PMID: 35145074 PMCID: PMC8831520 DOI: 10.1038/s41467-022-28435-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 01/24/2022] [Indexed: 02/06/2023] Open
Abstract
Type 2 diabetes is associated with insulin resistance, impaired pancreatic β-cell insulin secretion, and nonalcoholic fatty liver disease. Tissue-specific SWELL1 ablation impairs insulin signaling in adipose, skeletal muscle, and endothelium, and impairs β-cell insulin secretion and glycemic control. Here, we show that ICl,SWELL and SWELL1 protein are reduced in adipose and β-cells in murine and human diabetes. Combining cryo-electron microscopy, molecular docking, medicinal chemistry, and functional studies, we define a structure activity relationship to rationally-design active derivatives of a SWELL1 channel inhibitor (DCPIB/SN-401), that bind the SWELL1 hexameric complex, restore SWELL1 protein, plasma membrane trafficking, signaling, glycemic control and islet insulin secretion via SWELL1-dependent mechanisms. In vivo, SN-401 restores glycemic control, reduces hepatic steatosis/injury, improves insulin-sensitivity and insulin secretion in murine diabetes. These findings demonstrate that SWELL1 channel modulators improve SWELL1-dependent systemic metabolism in Type 2 diabetes, representing a first-in-class therapeutic approach for diabetes and nonalcoholic fatty liver disease. Type 2 diabetes is associated with insulin resistance, impaired insulin secretion and liver steatosis. Here the authors report a proof-of-concept study for small molecule SWELL1 modulators as a therapeutic approach to treat diabetes and associated liver steatosis by enhancing systemic insulin-sensitivity and insulin secretion in mice.
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Affiliation(s)
- Susheel K Gunasekar
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
| | - Litao Xie
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
| | - Ashutosh Kumar
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
| | - Juan Hong
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
| | - Pratik R Chheda
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, College of Pharmacy, Iowa City, IA, USA
| | - Chen Kang
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
| | - David M Kern
- Department of Molecular & Cell Biology, University of California Berkeley, Berkeley, CA, USA.,Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, USA
| | - Chau My-Ta
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Joshua Maurer
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
| | - John Heebink
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
| | - Eva E Gerber
- Department of Molecular & Cell Biology, University of California Berkeley, Berkeley, CA, USA.,Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, USA
| | - Wojciech J Grzesik
- Stead Family Department of Pediatrics, Endocrinology and Diabetes Division, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, USA
| | - Macaulay Elliot-Hudson
- Department of Internal Medicine, Cardiovascular Division, University of Iowa, Iowa City, IA, USA
| | - Yanhui Zhang
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, China
| | - Phillip Key
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
| | - Chaitanya A Kulkarni
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, College of Pharmacy, Iowa City, IA, USA
| | - Joseph W Beals
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, USA
| | - Gordon I Smith
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, USA
| | - Isaac Samuel
- Department of Surgery, University of Iowa, Carver College of Medicine, Iowa City, IA, USA
| | - Jessica K Smith
- Department of Surgery, University of Iowa, Carver College of Medicine, Iowa City, IA, USA
| | - Peter Nau
- Department of Surgery, University of Iowa, Carver College of Medicine, Iowa City, IA, USA
| | - Yumi Imai
- Department of Internal Medicine, Cardiovascular Division, University of Iowa, Iowa City, IA, USA
| | - Ryan D Sheldon
- Department of Biochemistry, University of Iowa, Iowa City, IA, USA
| | - Eric B Taylor
- Department of Biochemistry, University of Iowa, Iowa City, IA, USA
| | - Daniel J Lerner
- Senseion Therapeutics Inc, BioGenerator Labs, St Louis, MO, USA
| | - Andrew W Norris
- Stead Family Department of Pediatrics, Endocrinology and Diabetes Division, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, USA
| | - Samuel Klein
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, USA
| | - Stephen G Brohawn
- Department of Molecular & Cell Biology, University of California Berkeley, Berkeley, CA, USA.,Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, USA
| | - Robert Kerns
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, College of Pharmacy, Iowa City, IA, USA
| | - Rajan Sah
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA.
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13
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Guo F, Seldin M, Péterfy M, Charugundla S, Zhou Z, Lee SD, Mouton A, Rajbhandari P, Zhang W, Pellegrini M, Tontonoz P, Lusis AJ, Shih DM. NOTUM promotes thermogenic capacity and protects against diet-induced obesity in male mice. Sci Rep 2021; 11:16409. [PMID: 34385484 PMCID: PMC8361163 DOI: 10.1038/s41598-021-95720-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/28/2021] [Indexed: 11/29/2022] Open
Abstract
We recently showed that NOTUM, a liver-secreted Wnt inhibitor, can acutely promote browning of white adipose. We now report studies of chronic overexpression of NOTUM in liver indicating that it protects against diet-induced obesity and improves glucose homeostasis in mice. Adeno-associated virus (AAV) vectors were used to overexpress GFP or mouse Notum in the livers of male C57BL/6J mice and the mice were fed an obesifying diet. After 14 weeks of high fat, high sucrose diet feeding, the AAV-Notum mice exhibited decreased obesity and improved glucose tolerance compared to the AAV-GFP mice. Gene expression and immunoblotting analysis of the inguinal fat and brown fat revealed increased expression of beige/brown adipocyte markers in the AAV-Notum group, suggesting enhanced thermogenic capacity by NOTUM. A β3 adrenergic receptor agonist-stimulated lipolysis test suggested increased lipolysis capacity by NOTUM. The levels of collagen and C–C motif chemokine ligand 2 (CCL2) in the epididymal white adipose tissue of the AAV-Notum mice were significantly reduced, suggesting decreased fibrosis and inflammation, respectively. RNA sequencing analysis of inguinal white adipose of 4-week chow diet-fed mice revealed a highly significant enrichment of extracellular matrix (ECM) functional cluster among the down-regulated genes in the AAV-Notum group, suggesting a potential mechanism contributing to improved glucose homeostasis. Our in vitro studies demonstrated that recombinant human NOTUM protein blocked the inhibitory effects of WNT3A on brown adipocyte differentiation. Furthermore, NOTUM attenuated WNT3A’s effects on upregulation of TGF-β signaling and its downstream targets. Overall, our data suggest that NOTUM modulates adipose tissue function by promoting thermogenic capacity and inhibiting fibrosis through inhibition of Wnt signaling.
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Affiliation(s)
- Fangfei Guo
- Department of Microbiology, Immunology, and Molecular Genetics, Division of Cardiology, Department of Medicine, Department of Human Genetics, University of California, 10833 Le Conte Avenue, A2-237 CHS, Los Angeles, CA, 90095-1679, USA
| | - Marcus Seldin
- Department of Biological Chemistry and Center for Epigenetics and Metabolism, University of California, Irvine, CA, 92697, USA
| | - Miklós Péterfy
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA, 91766, USA
| | - Sarada Charugundla
- Department of Microbiology, Immunology, and Molecular Genetics, Division of Cardiology, Department of Medicine, Department of Human Genetics, University of California, 10833 Le Conte Avenue, A2-237 CHS, Los Angeles, CA, 90095-1679, USA
| | - Zhiqiang Zhou
- Department of Microbiology, Immunology, and Molecular Genetics, Division of Cardiology, Department of Medicine, Department of Human Genetics, University of California, 10833 Le Conte Avenue, A2-237 CHS, Los Angeles, CA, 90095-1679, USA
| | - Stephen D Lee
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Alice Mouton
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, 90095, USA
| | - Prashant Rajbhandari
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine Mount Sinai, New York, NY, 10029, USA
| | - Wenchao Zhang
- Department of Microbiology, Immunology, and Molecular Genetics, Division of Cardiology, Department of Medicine, Department of Human Genetics, University of California, 10833 Le Conte Avenue, A2-237 CHS, Los Angeles, CA, 90095-1679, USA.,The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Department of Cardiology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China.,Department of Critical Care Medicine, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Matteo Pellegrini
- Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA, 90095, USA
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Aldons J Lusis
- Department of Microbiology, Immunology, and Molecular Genetics, Division of Cardiology, Department of Medicine, Department of Human Genetics, University of California, 10833 Le Conte Avenue, A2-237 CHS, Los Angeles, CA, 90095-1679, USA
| | - Diana M Shih
- Department of Microbiology, Immunology, and Molecular Genetics, Division of Cardiology, Department of Medicine, Department of Human Genetics, University of California, 10833 Le Conte Avenue, A2-237 CHS, Los Angeles, CA, 90095-1679, USA.
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14
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Worley BL, Auen T, Arnold AC, Monia BP, Hempel N, Czyzyk TA. Antisense oligonucleotide-mediated knockdown of Mpzl3 attenuates the negative metabolic effects of diet-induced obesity in mice. Physiol Rep 2021; 9:e14853. [PMID: 33991450 PMCID: PMC8123547 DOI: 10.14814/phy2.14853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 04/05/2021] [Indexed: 02/06/2023] Open
Abstract
Previously, we demonstrated that global knockout (KO) of the gene encoding myelin protein zero‐like 3 (Mpzl3) results in reduced body weight and adiposity, increased energy expenditure, and reduced hepatic lipid synthesis in mice. These mice also exhibit cyclic and progressive alopecia which may contribute to the observed hypermetabolic phenotype. The goal of the current study was to determine if acute and peripherally restricted knockdown of Mpzl3 could ameliorate the negative metabolic effects of exposure to a high‐fat and sucrose, energy‐dense (HED) diet similar to what was observed in global Mpzl3 KO mice in the absence of a skin phenotype. Mpzl3 antisense oligonucleotide (ASO) administration dose‐dependently decreased fat mass and circulating lipids in HED‐fed C57BL/6N mice. These changes were accompanied by a decrease in respiratory exchange ratio, a reduction in energy expenditure and food intake, a decrease in expression of genes regulating de novo lipogenesis in white adipose tissue, and an upregulation of genes associated with steroid hormone biosynthesis in liver, thermogenesis in brown adipose tissue and fatty acid transport in skeletal muscle. These data demonstrate that resistance to the negative metabolic effects of HED is a direct effect of Mpzl3 knockdown, rather than compensatory changes that could be associated with deletion of Mpzl3 during development in global KO mice. Inhibiting MPZL3 could be a potential therapeutic approach for the treatment of obesity and associated dyslipidemia.
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Affiliation(s)
- Beth L Worley
- Department of Anesthesiology & Perioperative Medicine, Penn State University College of Medicine, Hershey, PA, USA.,Department of Pharmacology, Penn State University College of Medicine, Hershey, PA, USA.,Biomedical Sciences Program, Penn State University College of Medicine, Hershey, PA, USA
| | - Thomas Auen
- Department of Anesthesiology & Perioperative Medicine, Penn State University College of Medicine, Hershey, PA, USA
| | - Amy C Arnold
- Department of Neural & Behavioral Sciences, Penn State University College of Medicine, Hershey, PA, USA
| | | | - Nadine Hempel
- Department of Pharmacology, Penn State University College of Medicine, Hershey, PA, USA
| | - Traci A Czyzyk
- Department of Anesthesiology & Perioperative Medicine, Penn State University College of Medicine, Hershey, PA, USA.,Department of Neural & Behavioral Sciences, Penn State University College of Medicine, Hershey, PA, USA
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15
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ARC GHR Neurons Regulate Muscle Glucose Uptake. Cells 2021; 10:cells10051093. [PMID: 34063647 PMCID: PMC8147615 DOI: 10.3390/cells10051093] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/27/2021] [Accepted: 04/29/2021] [Indexed: 12/31/2022] Open
Abstract
The growth hormone receptor (GHR) is expressed in brain regions that are known to participate in the regulation of energy homeostasis and glucose metabolism. We generated a novel transgenic mouse line (GHRcre) to characterize GHR-expressing neurons specifically in the arcuate nucleus of the hypothalamus (ARC). Here, we demonstrate that ARCGHR+ neurons are co-localized with agouti-related peptide (AgRP), growth hormone releasing hormone (GHRH), and somatostatin neurons, which are activated by GH stimulation. Using the designer receptors exclusively activated by designer drugs (DREADD) technique to control the ARCGHR+ neuronal activity, we demonstrate that the activation of ARCGHR+ neurons elevates a respiratory exchange ratio (RER) under both fed and fasted conditions. However, while the activation of ARCGHR+ promotes feeding, under fasting conditions, the activation of ARCGHR+ neurons promotes glucose over fat utilization in the body. This effect was accompanied by significant improvements in glucose tolerance, and was specific to GHR+ versus GHRH+ neurons. The activation of ARCGHR+ neurons increased glucose turnover and whole-body glycolysis, as revealed by hyperinsulinemic-euglycemic clamp studies. Remarkably, the increased insulin sensitivity upon the activation of ARCGHR+ neurons was tissue-specific, as the insulin-stimulated glucose uptake was specifically elevated in the skeletal muscle, in parallel with the increased expression of muscle glycolytic genes. Overall, our results identify the GHR-expressing neuronal population in the ARC as a major regulator of glycolysis and muscle insulin sensitivity in vivo.
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16
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TeSlaa T, Bartman CR, Jankowski CSR, Zhang Z, Xu X, Xing X, Wang L, Lu W, Hui S, Rabinowitz JD. The Source of Glycolytic Intermediates in Mammalian Tissues. Cell Metab 2021; 33:367-378.e5. [PMID: 33472024 PMCID: PMC8088818 DOI: 10.1016/j.cmet.2020.12.020] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 10/05/2020] [Accepted: 12/29/2020] [Indexed: 12/17/2022]
Abstract
Glycolysis plays a central role in organismal metabolism, but its quantitative inputs across mammalian tissues remain unclear. Here we use 13C-tracing in mice to quantify glycolytic intermediate sources: circulating glucose, intra-tissue glycogen, and circulating gluconeogenic precursors. Circulating glucose is the main source of circulating lactate, the primary end product of tissue glycolysis. Yet circulating glucose highly labels glycolytic intermediates in only a few tissues: blood, spleen, diaphragm, and soleus muscle. Most glycolytic intermediates in the bulk of body tissue, including liver and quadriceps muscle, come instead from glycogen. Gluconeogenesis contributes less but also broadly to glycolytic intermediates, and its flux persists with physiologic feeding (but not hyperinsulinemic clamp). Instead of suppressing gluconeogenesis, feeding activates oxidation of circulating glucose and lactate to maintain glucose homeostasis. Thus, the bulk of the body slowly breaks down internally stored glycogen while select tissues rapidly catabolize circulating glucose to lactate for oxidation throughout the body.
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Affiliation(s)
- Tara TeSlaa
- Lewis Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Caroline R Bartman
- Lewis Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Connor S R Jankowski
- Lewis Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Zhaoyue Zhang
- Lewis Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Xincheng Xu
- Lewis Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Xi Xing
- Lewis Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Lin Wang
- Lewis Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Wenyun Lu
- Lewis Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Sheng Hui
- Lewis Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Washington Road, Princeton, NJ 08544, USA; Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, 655 Huntington Avenue, Boston, MA 02115, USA
| | - Joshua D Rabinowitz
- Lewis Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Washington Road, Princeton, NJ 08544, USA.
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17
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MacDonald AJ, Yang YHC, Cruz AM, Beall C, Ellacott KLJ. Brain-Body Control of Glucose Homeostasis-Insights From Model Organisms. Front Endocrinol (Lausanne) 2021; 12:662769. [PMID: 33868184 PMCID: PMC8044781 DOI: 10.3389/fendo.2021.662769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/12/2021] [Indexed: 12/15/2022] Open
Abstract
Tight regulation of blood glucose is essential for long term health. Blood glucose levels are defended by the correct function of, and communication between, internal organs including the gastrointestinal tract, pancreas, liver, and brain. Critically, the brain is sensitive to acute changes in blood glucose level and can modulate peripheral processes to defend against these deviations. In this mini-review we highlight select key findings showcasing the utility, strengths, and limitations of model organisms to study brain-body interactions that sense and control blood glucose levels. First, we discuss the large platform of genetic tools available to investigators studying mice and how this field may yet reveal new modes of communication between peripheral organs and the brain. Second, we discuss how rats, by virtue of their size, have unique advantages for the study of CNS control of glucose homeostasis and note that they may more closely model some aspects of human (patho)physiology. Third, we discuss the nascent field of studying the CNS control of blood glucose in the zebrafish which permits ease of genetic modification, large-scale measurements of neural activity and live imaging in addition to high-throughput screening. Finally, we briefly discuss glucose homeostasis in drosophila, which have a distinct physiology and glucoregulatory systems to vertebrates.
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18
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Carter CS, Richardson A, Huffman DM, Austad S. Bring Back the Rat! J Gerontol A Biol Sci Med Sci 2020; 75:405-415. [PMID: 31894235 DOI: 10.1093/gerona/glz298] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Indexed: 12/12/2022] Open
Abstract
As 2020 is "The Year of the Rat" in the Chinese astrological calendar, it seems an appropriate time to consider whether we should bring back the laboratory rat to front-and-center in research on the basic biology of mammalian aging. Beginning in the 1970s, aging research with rats became common, peaking in 1992 but then declined dramatically by 2018 as the mouse became preeminent. The purpose of this review is to highlight some of the historical contributions as well as current advantages of the rat as a mammalian model of human aging, because we suspect at least a generation of researchers is no longer aware of this history or these advantages. Herein, we compare and contrast the mouse and rat in the context of several biological domains relevant to their use as appropriate models of aging: phylogeny/domestication, longevity interventions, pathology/physiology, and behavior/cognition. It is not the goal of this review to give a complete characterization of the differences between mice and rats, but to provide important examples of why using rats as well as mice is important to advance our understanding of the biology of aging.
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Affiliation(s)
- Christy S Carter
- Department of Medicine, Division of Gerontology, Geriatrics and Palliative Care, School of Medicine, University of Alabama at Birmingham
| | - Arlan Richardson
- Department of Biochemistry and Molecular Biology, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Science Center, and the Oklahoma City VA Medical Center
| | - Derek M Huffman
- Department of Molecular Pharmacology, Department of Medicine, and Institute for Aging Research, Albert Einstein College of Medicine, Bronx, New York
| | - Steven Austad
- Department of Biology, College of Arts and Sciences, University of Alabama at Birmingham
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19
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Raje V, Ahern KW, Martinez BA, Howell NL, Oenarto V, Granade ME, Kim JW, Tundup S, Bottermann K, Gödecke A, Keller SR, Kadl A, Bland ML, Harris TE. Adipocyte lipolysis drives acute stress-induced insulin resistance. Sci Rep 2020; 10:18166. [PMID: 33097799 PMCID: PMC7584576 DOI: 10.1038/s41598-020-75321-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 10/09/2020] [Indexed: 12/12/2022] Open
Abstract
Stress hyperglycemia and insulin resistance are evolutionarily conserved metabolic adaptations to severe injury including major trauma, burns, or hemorrhagic shock (HS). In response to injury, the neuroendocrine system increases secretion of counterregulatory hormones that promote rapid mobilization of nutrient stores, impair insulin action, and ultimately cause hyperglycemia, a condition known to impair recovery from injury in the clinical setting. We investigated the contributions of adipocyte lipolysis to the metabolic response to acute stress. Both surgical injury with HS and counterregulatory hormone (epinephrine) infusion profoundly stimulated adipocyte lipolysis and simultaneously triggered insulin resistance and hyperglycemia. When lipolysis was inhibited, the stress-induced insulin resistance and hyperglycemia were largely abolished demonstrating an essential requirement for adipocyte lipolysis in promoting stress-induced insulin resistance. Interestingly, circulating non-esterified fatty acid levels did not increase with lipolysis or correlate with insulin resistance during acute stress. Instead, we show that impaired insulin sensitivity correlated with circulating levels of the adipokine resistin in a lipolysis-dependent manner. Our findings demonstrate the central importance of adipocyte lipolysis in the metabolic response to injury. This insight suggests new approaches to prevent insulin resistance and stress hyperglycemia in trauma and surgery patients and thereby improve outcomes.
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Affiliation(s)
- Vidisha Raje
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Katelyn W Ahern
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Brittany A Martinez
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Nancy L Howell
- Department of Medicine, Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, USA
| | - Vici Oenarto
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.,Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Mitchell E Granade
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Jae Woo Kim
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Smanla Tundup
- Department of Medicine, Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville, VA, USA
| | | | - Axel Gödecke
- Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Susanna R Keller
- Department of Medicine, Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, USA
| | - Alexandra Kadl
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.,Department of Medicine, Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville, VA, USA
| | - Michelle L Bland
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.
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20
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Carter CS, Huang SC, Searby CC, Cassaidy B, Miller MJ, Grzesik WJ, Piorczynski TB, Pak TK, Walsh SA, Acevedo M, Zhang Q, Mapuskar KA, Milne GL, Hinton AO, Guo DF, Weiss R, Bradberry K, Taylor EB, Rauckhorst AJ, Dick DW, Akurathi V, Falls-Hubert KC, Wagner BA, Carter WA, Wang K, Norris AW, Rahmouni K, Buettner GR, Hansen JM, Spitz DR, Abel ED, Sheffield VC. Exposure to Static Magnetic and Electric Fields Treats Type 2 Diabetes. Cell Metab 2020; 32:561-574.e7. [PMID: 33027675 PMCID: PMC7819711 DOI: 10.1016/j.cmet.2020.09.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/29/2020] [Accepted: 09/11/2020] [Indexed: 12/17/2022]
Abstract
Aberrant redox signaling underlies the pathophysiology of many chronic metabolic diseases, including type 2 diabetes (T2D). Methodologies aimed at rebalancing systemic redox homeostasis have had limited success. A noninvasive, sustained approach would enable the long-term control of redox signaling for the treatment of T2D. We report that static magnetic and electric fields (sBE) noninvasively modulate the systemic GSH-to-GSSG redox couple to promote a healthier systemic redox environment that is reducing. Strikingly, when applied to mouse models of T2D, sBE rapidly ameliorates insulin resistance and glucose intolerance in as few as 3 days with no observed adverse effects. Scavenging paramagnetic byproducts of oxygen metabolism with SOD2 in hepatic mitochondria fully abolishes these insulin sensitizing effects, demonstrating that mitochondrial superoxide mediates induction of these therapeutic changes. Our findings introduce a remarkable redox-modulating phenomenon that exploits endogenous electromagneto-receptive mechanisms for the noninvasive treatment of T2D, and potentially other redox-related diseases.
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Affiliation(s)
- Calvin S Carter
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA.
| | - Sunny C Huang
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA; Medical Scientist Training Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Charles C Searby
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Benjamin Cassaidy
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Michael J Miller
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
| | - Wojciech J Grzesik
- Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Ted B Piorczynski
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, USA
| | - Thomas K Pak
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA; Medical Scientist Training Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Susan A Walsh
- Department of Radiology, Division of Nuclear Medicine, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Michael Acevedo
- Department of Radiology, Division of Nuclear Medicine, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Qihong Zhang
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Kranti A Mapuskar
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Ginger L Milne
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Antentor O Hinton
- Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Deng-Fu Guo
- Department of Neuroscience and Pharmacology, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Robert Weiss
- Department of Internal Medicine, Division of Cardiology, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Kyle Bradberry
- Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Eric B Taylor
- Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Department of Molecular Physiology and Biophysics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Adam J Rauckhorst
- Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Department of Molecular Physiology and Biophysics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - David W Dick
- Department of Radiology, Division of Nuclear Medicine, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Vamsidhar Akurathi
- Department of Radiology, Division of Nuclear Medicine, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Kelly C Falls-Hubert
- Medical Scientist Training Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Brett A Wagner
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Walter A Carter
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Kai Wang
- College of Public Health, Department of Biostatistics, University of Iowa, Iowa City, IA, USA
| | - Andrew W Norris
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA; Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Kamal Rahmouni
- Department of Neuroscience and Pharmacology, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Garry R Buettner
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Jason M Hansen
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, USA
| | - Douglas R Spitz
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - E Dale Abel
- Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Val C Sheffield
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA.
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21
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Lomax TM, Ashraf S, Yilmaz G, Harmancey R. Loss of Uncoupling Protein 3 Attenuates Western Diet-Induced Obesity, Systemic Inflammation, and Insulin Resistance in Rats. Obesity (Silver Spring) 2020; 28:1687-1697. [PMID: 32716607 PMCID: PMC7483834 DOI: 10.1002/oby.22879] [Citation(s) in RCA: 5] [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: 01/03/2020] [Revised: 04/09/2020] [Accepted: 04/29/2020] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Uncoupling protein 3 (UCP3) is a mitochondrial carrier related to fatty acid metabolism. Although gene variants of UCP3 are associated with human obesity, their contribution to increased adiposity remains unclear. This study investigated the impact that loss of UCP3 has on diet-induced obesity in rats. METHODS Male UCP3 knockout rats (ucp3-/- ) and wild-type littermates (ucp3+/+ ) were fed a high-fat, high-carbohydrate Western diet for 21 weeks. Body composition was analyzed by EchoMRI. Whole-body insulin sensitivity and rates of tissue glucose uptake were determined by using hyperinsulinemic-euglycemic clamp. Changes in tissue physiology were interrogated by microscopy and RNA sequencing. RESULTS Loss of UCP3 decreased fat mass gain, white adipocytes size, and systemic inflammation. The ucp3-/- rats also exhibited preserved insulin sensitivity and increased glucose uptake in interscapular brown adipose tissue (iBAT). Brown adipocytes from ucp3-/- rats were protected from cellular degeneration caused by lipid accumulation and from reactive oxygen species-induced protein sulfonation. Increased glutathione levels in iBAT from ucp3-/- rats were linked to upregulation of genes encoding enzymes from the transsulfuration pathway in that tissue. CONCLUSIONS Loss of UCP3 partially protects rats from diet-induced obesity. This phenotype is related to induction of a compensatory antioxidant mechanism and prevention of iBAT whitening.
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Affiliation(s)
- Tyler M. Lomax
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
- Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA
- Mississippi Center for Heart Research, University of Mississippi Medical Center, Jackson, MS, USA
| | - Sadia Ashraf
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
- Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA
- Mississippi Center for Heart Research, University of Mississippi Medical Center, Jackson, MS, USA
| | - Gizem Yilmaz
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
- Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA
- Mississippi Center for Heart Research, University of Mississippi Medical Center, Jackson, MS, USA
| | - Romain Harmancey
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
- Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA
- Mississippi Center for Heart Research, University of Mississippi Medical Center, Jackson, MS, USA
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22
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Adipocyte G i signaling is essential for maintaining whole-body glucose homeostasis and insulin sensitivity. Nat Commun 2020; 11:2995. [PMID: 32532984 PMCID: PMC7293267 DOI: 10.1038/s41467-020-16756-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 05/18/2020] [Indexed: 12/13/2022] Open
Abstract
Adipocyte dysfunction links obesity to insulin resistance and type 2 diabetes. Adipocyte function is regulated by receptor-mediated activation of heterotrimeric G proteins. Little is known about the potential in vivo metabolic roles of Gi-type G proteins expressed by adipocytes, primarily due to the lack of suitable animal models. To address this question, we generated mice lacking functional Gi proteins selectively in adipocytes. Here we report that these mutant mice displayed significantly impaired glucose tolerance and reduced insulin sensitivity when maintained on an obesogenic diet. In contrast, using a chemogenetic strategy, we demonstrated that activation of Gi signaling selectively in adipocytes greatly improved glucose homeostasis and insulin signaling. We also elucidated the cellular mechanisms underlying the observed metabolic phenotypes. Our data support the concept that adipocyte Gi signaling is essential for maintaining euglycemia. Drug-mediated activation of adipocyte Gi signaling may prove beneficial for restoring proper glucose homeostasis in type 2 diabetes. Gs-coupled receptor signaling is well known to modulate adipocyte metabolism, but the role of Gi-coupled receptors in adipose tissue is less well understood. Here the authors show that signaling via Gi-type G proteins expressed by adipocytes is essential for maintaining proper blood glucose homeostasis.
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23
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Hull RL, Hackney DJ, Giering EL, Zraika S. Acclimation Prior to an Intraperitoneal Insulin Tolerance Test to Mitigate Stress-Induced Hyperglycemia in Conscious Mice. J Vis Exp 2020:10.3791/61179. [PMID: 32510516 PMCID: PMC10499336 DOI: 10.3791/61179] [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] [Indexed: 10/31/2022] Open
Abstract
The insulin tolerance test is commonly used in metabolic studies to assess whole body insulin sensitivity in rodents. It is a relatively simple test that involves measurement of blood glucose levels over time following a single intraperitoneal injection of insulin. Given that it is performed in the conscious state and blood is often collected via a tail snip, it has the potential to elicit a stress response from animals due to anxiety associated with handling and blood collection. As such, a stress-induced rise in blood glucose can occur, making it difficult to detect and interpret the primary endpoint measure, namely an insulin-mediated reduction in blood glucose. This has been seen in many mouse strains, and is quite common in diabetic db/db mice, where glucose levels can increase, rather than decrease, after insulin administration. Here, we describe a method of acclimating mice to handling, injections and blood sampling prior to performing the insulin tolerance test. We find that this lowers stress-induced hyperglycemia and results in data that more accurately reflects whole body insulin sensitivity.
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Affiliation(s)
- Rebecca L Hull
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System; Department of Medicine, University of Washington
| | - Daryl J Hackney
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System
| | - Elizabeth L Giering
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System; Department of Medicine, University of Washington
| | - Sakeneh Zraika
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System; Department of Medicine, University of Washington;
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24
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Correnti J, Lin C, Brettschneider J, Kuriakose A, Jeon S, Scorletti E, Oranu A, McIver-Jenkins D, Kaneza I, Buyco D, Saiman Y, Furth EE, Argemi J, Bataller R, Holland WL, Carr RM. Liver-specific ceramide reduction alleviates steatosis and insulin resistance in alcohol-fed mice. J Lipid Res 2020; 61:983-994. [PMID: 32398264 PMCID: PMC7328039 DOI: 10.1194/jlr.ra119000446] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 04/29/2020] [Indexed: 12/20/2022] Open
Abstract
Alcohol's impairment of both hepatic lipid metabolism and insulin resistance (IR) are key drivers of alcoholic steatosis, the initial stage of alcoholic liver disease (ALD). Pharmacologic reduction of lipotoxic ceramide prevents alcoholic steatosis and glucose intolerance in mice, but potential off-target effects limit its strategic utility. Here, we employed a hepatic-specific acid ceramidase (ASAH) overexpression model to reduce hepatic ceramides in a Lieber-DeCarli model of experimental alcoholic steatosis. We examined effects of alcohol on hepatic lipid metabolism, body composition, energy homeostasis, and insulin sensitivity as measured by hyperinsulinemic-euglycemic clamp. Our results demonstrate that hepatic ceramide reduction ameliorates the effects of alcohol on hepatic lipid droplet (LD) accumulation by promoting VLDL secretion and lipophagy, the latter of which involves ceramide cross-talk between the lysosomal and LD compartments. We additionally demonstrate that hepatic ceramide reduction prevents alcohol's inhibition of hepatic insulin signaling. These effects on the liver are associated with a reduction in oxidative stress markers and are relevant to humans, as we observe peri- LD ASAH expression in human ALD. Together, our results suggest a potential role for hepatic ceramide inhibition in preventing ALD.
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Affiliation(s)
- Jason Correnti
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA
| | - Chelsea Lin
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA
| | | | - Amy Kuriakose
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA
| | - Sookyoung Jeon
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA
| | - Eleonora Scorletti
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA
| | - Amanke Oranu
- Division of Gastroenterology, United Health Services, Binghamton, NY
| | - Dru McIver-Jenkins
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA
| | - Isabelle Kaneza
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA
| | - Delfin Buyco
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA
| | - Yedidya Saiman
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA
| | - Emma E Furth
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA
| | - Josepmaria Argemi
- Center for Liver Diseases, Pittsburgh Research Center, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Ramon Bataller
- Center for Liver Diseases, Pittsburgh Research Center, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - William L Holland
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT
| | - Rotonya M Carr
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA. mailto:
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25
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Boland ML, Laker RC, Mather K, Nawrocki A, Oldham S, Boland BB, Lewis H, Conway J, Naylor J, Guionaud S, Feigh M, Veidal SS, Lantier L, McGuinness OP, Grimsby J, Rondinone CM, Jermutus L, Larsen MR, Trevaskis JL, Rhodes CJ. Resolution of NASH and hepatic fibrosis by the GLP-1R/GcgR dual-agonist Cotadutide via modulating mitochondrial function and lipogenesis. Nat Metab 2020; 2:413-431. [PMID: 32478287 PMCID: PMC7258337 DOI: 10.1038/s42255-020-0209-6] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Non-alcoholic fatty liver disease and steatohepatitis are highly associated with obesity and type 2 diabetes mellitus. Cotadutide, a GLP-1R/GcgR agonist, was shown to reduce blood glycemia, body weight and hepatic steatosis in patients with T2DM. Here, we demonstrate that the effects of Cotadutide to reduce body weight, food intake and improve glucose control are predominantly mediated through the GLP-1 signaling, while, its action on the liver to reduce lipid content, drive glycogen flux and improve mitochondrial turnover and function are directly mediated through Gcg signaling. This was confirmed by the identification of phosphorylation sites on key lipogenic and glucose metabolism enzymes in liver of mice treated with Cotadutide. Complementary metabolomic and transcriptomic analyses implicated lipogenic, fibrotic and inflammatory pathways, which are consistent with a unique therapeutic contribution of GcgR agonism by Cotadutide in vivo. Significantly, Cotadutide also alleviated fibrosis to a greater extent than Liraglutide or Obeticholic acid (OCA), despite adjusting dose to achieve similar weight loss in 2 preclinical mouse models of NASH. Thus Cotadutide, via direct hepatic (GcgR) and extra-hepatic (GLP-1R) effects, exerts multi-factorial improvement in liver function and is a promising therapeutic option for the treatment of steatohepatitis.
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Affiliation(s)
- Michelle L Boland
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Rhianna C Laker
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Karly Mather
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Arkadiusz Nawrocki
- Department of Biochemistry and Molecular Biology, PR group, University of Southern Denmark, Odense, Denmark
| | - Stephanie Oldham
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Brandon B Boland
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Hilary Lewis
- Research and Early Development, Oncology, AstraZeneca, Cambridge, UK
| | - James Conway
- Translational Sciences, AstraZeneca, Gaithersburg, MD, USA
| | - Jacqueline Naylor
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | | | | | | | - Louise Lantier
- Vanderbilt University Mouse Metabolic Phenotyping Center, Nashville, TN, USA
| | - Owen P McGuinness
- Vanderbilt University Mouse Metabolic Phenotyping Center, Nashville, TN, USA
| | - Joseph Grimsby
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Cristina M Rondinone
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Lutz Jermutus
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Martin R Larsen
- Department of Biochemistry and Molecular Biology, PR group, University of Southern Denmark, Odense, Denmark
| | - James L Trevaskis
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
- Gilead Sciences, Foster City, CA, USA
| | - Christopher J Rhodes
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA.
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26
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Esmaeili Mohsen Abadi S, Balouchzadeh R, Uzun G, Ko HS, Lee HF, Park S, Kwon G. Tracking changes of the parameters of glucose-insulin homeostasis during the course of obesity in B6D2F1 mice. Heliyon 2020; 6:e03251. [PMID: 32042976 PMCID: PMC7002827 DOI: 10.1016/j.heliyon.2020.e03251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/25/2019] [Accepted: 01/14/2020] [Indexed: 12/12/2022] Open
Abstract
Obesity is one of the primary causes of type 2 diabetes mellitus (T2DM). To better understand how obesity impairs glucose-insulin homeostasis, we tracked fasting blood glucose and insulin levels and the key components of glucose-insulin homeostasis for 7 months in high fat diet (HFD; 45% fat) fed mice (n = 8). Every 2 weeks we measured body weight, fasting blood glucose and insulin levels, and estimated 5 key rate constants of glucose-insulin homeostasis using the methods established previously (Heliyon 3: e00310, 2017). Mice gained weight steadily, more than doubling their weights after 7 months (23.6 ± 0.5 to 52.3 ± 1.4 g). Fasting (basal) insulin levels were elevated (221.3 ± 16.7 to 1043.1 ± 90.5 pmol l-1) but fasting blood glucose levels unexpectedly returned to the baseline levels (152.8 ± 7.0 to 152.0 ± 7.2 mg/dl) despite significantly elevated levels (216.8 ± 44.9 mg/dl, average of 3 highest values for 8 mice) during the experimental period. After 7 months of HFD feeding, the rate constants for insulin secretion (k1), insulin-independent glucose uptake (k3), and insulin concentration where liver switches from glucose uptake to release (Ipi) were significantly elevated. Insulin-dependent glucose uptake (k2) and rate constant of liver glucose transfer (k4) were lowered but no statistical significance was reached. The novel and key finding of this study is the wide range of fluctuations of the rate constants during the course of obesity, reflecting the body's compensatory responses against metabolic alterations caused by obesity.
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Affiliation(s)
| | - Ramin Balouchzadeh
- School of Engineering, Southern Illinois University Edwardsville, Edwardsville, IL, 62026, United States
| | - Guney Uzun
- School of Engineering, Southern Illinois University Edwardsville, Edwardsville, IL, 62026, United States
| | - Hoo Sang Ko
- School of Engineering, Southern Illinois University Edwardsville, Edwardsville, IL, 62026, United States
| | - H Felix Lee
- School of Engineering, Southern Illinois University Edwardsville, Edwardsville, IL, 62026, United States
| | - Sarah Park
- Library and Information Services, Southern Illinois University Edwardsville, Edwardsville, IL, 62026, United States
| | - Guim Kwon
- School of Pharmacy, Southern Illinois University Edwardsville, Edwardsville, IL, 62026, United States
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27
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Watanabe M, Singhal G, Fisher FM, Beck TC, Morgan DA, Socciarelli F, Mather ML, Risi R, Bourke J, Rahmouni K, McGuinness OP, Flier JS, Maratos-Flier E. Liver-derived FGF21 is essential for full adaptation to ketogenic diet but does not regulate glucose homeostasis. Endocrine 2020; 67:95-108. [PMID: 31728756 PMCID: PMC7948212 DOI: 10.1007/s12020-019-02124-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 10/22/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND Fibroblast growth factor 21 (FGF21) is expressed in several metabolically active tissues, including liver, fat, and acinar pancreas, and has pleiotropic effects on metabolic homeostasis. The dominant source of FGF21 in the circulation is the liver. OBJECTIVE AND METHODS To analyze the physiological functions of hepatic FGF21, we generated a hepatocyte-specific knockout model (LKO) by mating albumin-Cre mice with FGF21 flox/flox (fl/fl) mice and challenged it with different nutritional models. RESULTS Mice fed a ketogenic diet typically show increased energy expenditure; this effect was attenuated in LKO mice. LKO on KD also developed hepatic pathology and altered hepatic lipid homeostasis. When evaluated using hyperinsulinemic-euglycemic clamps, glucose infusion rates, hepatic glucose production, and glucose uptake were similar between fl/fl and LKO DIO mice. CONCLUSIONS We conclude that liver-derived FGF21 is important for complete adaptation to ketosis but has a more limited role in the regulation of glycemic homeostasis.
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Affiliation(s)
- Mikiko Watanabe
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161, Rome, Italy
| | - Garima Singhal
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Ffolliott M Fisher
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Thomas C Beck
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Donald A Morgan
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Fabio Socciarelli
- Department of Oncology-Pathology, Karolinska Institutet, 171 76, Stockholm, Sweden
| | - Marie L Mather
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Renata Risi
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161, Rome, Italy
| | - Jared Bourke
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Kamal Rahmouni
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Owen P McGuinness
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Jeffrey S Flier
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02215, USA
| | - Eleftheria Maratos-Flier
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA.
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28
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Zhao Y, Zhao X, Chen V, Feng Y, Wang L, Croniger C, Conlon RA, Markowitz S, Fearon E, Puchowicz M, Brunengraber H, Hao Y, Wang Z. Colorectal cancers utilize glutamine as an anaplerotic substrate of the TCA cycle in vivo. Sci Rep 2019; 9:19180. [PMID: 31844152 PMCID: PMC6915720 DOI: 10.1038/s41598-019-55718-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 11/28/2019] [Indexed: 12/13/2022] Open
Abstract
Cancer cells in culture rely on glutamine as an anaplerotic substrate to replenish tricarboxylic acid (TCA) cycle intermediates that have been consumed. but it is uncertain whether cancers in vivo depend on glutamine for anaplerosis. Here, following in vivo infusions of [13C5]-glutamine in mice bearing subcutaneous colon cancer xenografts, we showed substantial amounts of infused [13C5]-glutamine enters the TCA cycle in the tumors. Consistent with our prior observation that colorectal cancers (CRCs) with oncogenic mutations in the phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic (PIK3CA) subunit are more dependent on glutamine than CRCs with wild type PIK3CA, labeling from glutamine to most TCA cycle intermediates was higher in PIK3CA-mutant subcutaneous xenograft tumors than in wild type PIK3CA tumors. Moreover, using orthotopic mouse colon tumors estalished from human CRC cells or patient-derived xenografts, we demonstrated substantial amounts of infused [13C5]-glutamine enters the TCA cycle in the tumors and tumors utilize anaplerotic glutamine to a greater extent than adjacent normal colon tissues. Similar results were seen in spontaneous colon tumors arising in genetically engineered mice. Our studies provide compelling evidence CRCs utilizes glutamine to replenish the TCA cycle in vivo, suggesting that targeting glutamine metabolism could be a therapeutic approach for CRCs, especially for PIK3CA-mutant CRCs.
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Affiliation(s)
- Yiqing Zhao
- Department of Genetics and Genome Sciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA.,Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA
| | - Xuan Zhao
- Department of Genetics and Genome Sciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA.,Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA
| | - Vanessa Chen
- Department of Genetics and Genome Sciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA.,Department of Nutrition, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA
| | - Ying Feng
- Departments of Internal Medicine, Human Genetics, and Pathology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Lan Wang
- Department of Nutrition, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA
| | - Colleen Croniger
- Department of Nutrition, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA
| | - Ronald A Conlon
- Department of Genetics and Genome Sciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA.,Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA
| | - Sanford Markowitz
- Department of Genetics and Genome Sciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA.,Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA.,Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA.,Seidman Cancer Center, University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
| | - Eric Fearon
- Departments of Internal Medicine, Human Genetics, and Pathology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Michelle Puchowicz
- Department of Nutrition, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA
| | - Henri Brunengraber
- Department of Nutrition, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA
| | - Yujun Hao
- Department of Genetics and Genome Sciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA. .,Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA. .,Shanghai Cancer Institute, Shanghai Jiao-Tong University School of Medicine Renji Hospital, 25/Ln 2200 Xietu Road, Shanghai, 200032, P.R. China.
| | - Zhenghe Wang
- Department of Genetics and Genome Sciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA. .,Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA.
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29
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Sarcolipin Signaling Promotes Mitochondrial Biogenesis and Oxidative Metabolism in Skeletal Muscle. Cell Rep 2019; 24:2919-2931. [PMID: 30208317 PMCID: PMC6481681 DOI: 10.1016/j.celrep.2018.08.036] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/30/2018] [Accepted: 08/13/2018] [Indexed: 12/19/2022] Open
Abstract
The major objective of this study was to understand the molecular basis of how sarcolipin uncoupling of SERCA regulates muscle oxidative metabolism. Using genetically engineered sarcolipin (SLN) mouse models and primary muscle cells, we demonstrate that SLN plays a crucial role in mitochondrial biogenesis and oxidative metabolism in muscle. Loss of SLN severely compromised muscle oxidative capacity without affecting fiber-type composition. Mice overexpressing SLN in fast-twitch glycolytic muscle reprogrammed mitochondrial phenotype, increasing fat utilization and protecting against high-fat dietinduced lipotoxicity. We show that SLN affects cytosolic Ca2+ transients and activates the Ca2+/ calmodulin-dependent protein kinase II (CamKII) and PGC1α axis to increase mitochondrial biogenesis and oxidative metabolism. These studies provide a fundamental framework for understanding the role of sarcoplasmic reticulum (SR)-Ca2+ cycling as an important factor in mitochondrial health and muscle metabolism. We propose that SLN can be targeted to enhance energy expenditure in muscle and prevent metabolic disease. Maurya et al. report that sarcolipin, a regulator of the SERCA pump, promotes mitochondrial biogenesis and oxidative phenotype in muscle. Loss of SLN decreases fat oxidation, whereas overexpression of SLN in muscle provides resistance against diet-induced lipotoxicity. By increasing cytosolic Ca2+ transients, SLN activates the CamKII-PGC1α signaling pathway to promote mitochondrial biogenesis.
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30
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Chen L, Chen XW, Huang X, Song BL, Wang Y, Wang Y. Regulation of glucose and lipid metabolism in health and disease. SCIENCE CHINA-LIFE SCIENCES 2019; 62:1420-1458. [PMID: 31686320 DOI: 10.1007/s11427-019-1563-3] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 10/15/2019] [Indexed: 02/08/2023]
Abstract
Glucose and fatty acids are the major sources of energy for human body. Cholesterol, the most abundant sterol in mammals, is a key component of cell membranes although it does not generate ATP. The metabolisms of glucose, fatty acids and cholesterol are often intertwined and regulated. For example, glucose can be converted to fatty acids and cholesterol through de novo lipid biosynthesis pathways. Excessive lipids are secreted in lipoproteins or stored in lipid droplets. The metabolites of glucose and lipids are dynamically transported intercellularly and intracellularly, and then converted to other molecules in specific compartments. The disorders of glucose and lipid metabolism result in severe diseases including cardiovascular disease, diabetes and fatty liver. This review summarizes the major metabolic aspects of glucose and lipid, and their regulations in the context of physiology and diseases.
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Affiliation(s)
- Ligong Chen
- School of Pharmaceutical Sciences, Beijing Advanced Innovation Center for Structural Biology, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Tsinghua University, Beijing, 100084, China.
| | - Xiao-Wei Chen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
| | - Yan Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
| | - Yiguo Wang
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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31
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Meister J, Bone DBJ, Godlewski G, Liu Z, Lee RJ, Vishnivetskiy SA, Gurevich VV, Springer D, Kunos G, Wess J. Metabolic effects of skeletal muscle-specific deletion of beta-arrestin-1 and -2 in mice. PLoS Genet 2019; 15:e1008424. [PMID: 31622341 PMCID: PMC6818801 DOI: 10.1371/journal.pgen.1008424] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/29/2019] [Accepted: 09/16/2019] [Indexed: 01/01/2023] Open
Abstract
Type 2 diabetes (T2D) has become a major health problem worldwide. Skeletal muscle (SKM) is the key tissue for whole-body glucose disposal and utilization. New drugs aimed at improving insulin sensitivity of SKM would greatly expand available therapeutic options. β-arrestin-1 and -2 (Barr1 and Barr2, respectively) are two intracellular proteins best known for their ability to mediate the desensitization and internalization of G protein-coupled receptors (GPCRs). Recent studies suggest that Barr1 and Barr2 regulate several important metabolic functions including insulin release and hepatic glucose production. Since SKM expresses many GPCRs, including the metabolically important β2-adrenergic receptor, the goal of this study was to examine the potential roles of Barr1 and Barr2 in regulating SKM and whole-body glucose metabolism. Using SKM-specific knockout (KO) mouse lines, we showed that the loss of SKM Barr2, but not of SKM Barr1, resulted in mild improvements in glucose tolerance in diet-induced obese mice. SKM-specific Barr1- and Barr2-KO mice did not show any significant differences in exercise performance. However, lack of SKM Barr2 led to increased glycogen breakdown following a treadmill exercise challenge. Interestingly, mice that lacked both Barr1 and Barr2 in SKM showed no significant metabolic phenotypes. Thus, somewhat surprisingly, our data indicate that SKM β-arrestins play only rather subtle roles (SKM Barr2) in regulating whole-body glucose homeostasis and SKM insulin sensitivity.
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Affiliation(s)
- Jaroslawna Meister
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States of America
- * E-mail: (JM); (JW)
| | - Derek B. J. Bone
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States of America
| | - Grzegorz Godlewski
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, United States of America
| | - Ziyi Liu
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, United States of America
| | - Regina J. Lee
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States of America
| | | | - Vsevolod V. Gurevich
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States of America
| | - Danielle Springer
- Murine Phenotyping Core, National Heart, Lung, and Blood Institute, Bethesda, MD, United States of America
| | - George Kunos
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, United States of America
| | - Jürgen Wess
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States of America
- * E-mail: (JM); (JW)
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32
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Peterson KR, Gutierrez DA, Kikuchi T, Anderson-Baucum EK, Winn NC, Shuey MM, Bolus WR, McGuinness OP, Hasty AH. Impaired insulin signaling in the B10.D2- Hc0 H2d H2- T18c/oSnJ mouse model of complement factor 5 deficiency. Am J Physiol Endocrinol Metab 2019; 317:E200-E211. [PMID: 31084499 PMCID: PMC6732470 DOI: 10.1152/ajpendo.00042.2019] [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: 02/05/2019] [Revised: 04/16/2019] [Accepted: 04/30/2019] [Indexed: 11/22/2022]
Abstract
Given the chemoattractant potential of complement factor 5 (C5) and its increased expression in adipose tissue (AT) of obese mice, we determined whether this protein of the innate immune system impacts insulin action. C5 control (C5cont) and spontaneously C5-deficient (C5def, B10.D2-Hc0 H2d H2-T18c/oSnJ) mice were placed on low- and high-fat diets to investigate their inflammatory and metabolic phenotypes. Adenoviral delivery was used to evaluate the effects of exogenous C5 on systemic metabolism. C5def mice gained less weight than controls while fed a high-fat diet, accompanied by reduced AT inflammation, liver mass, and liver triglyceride content. Despite these beneficial metabolic effects, C5def mice demonstrated severe glucose intolerance and systemic insulin resistance, as well as impaired insulin signaling in liver and AT. C5def mice also exhibited decreased expression of insulin receptor (INSR) gene and protein, as well as improper processing of pro-INSR. These changes were not due to the C5 deficiency alone as other C5-deficient models did not recapitulate the INSR processing defect; rather, in addition to the mutation in the C5 gene, whole genome sequencing revealed an intronic 31-bp deletion in the Insr gene in the B10.D2-Hc0 H2d H2-T18c/oSnJ model. Irrespective of the genetic defect, adenoviral delivery of C5 improved insulin sensitivity in both C5cont and C5def mice, indicating an insulin-sensitizing function of C5.
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Affiliation(s)
- Kristin R Peterson
- Department of Pharmacology, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Dario A Gutierrez
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
- Investigational Biology, Merck Exploratory Science Center , Cambridge, Massachusetts
| | - Takuya Kikuchi
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Emily K Anderson-Baucum
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Nathan C Winn
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Megan M Shuey
- Department of Genetic Medicine, Vanderbilt University Medical Center , Nashville, Tennessee
| | - William R Bolus
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Owen P McGuinness
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Alyssa H Hasty
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee
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33
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Yam M, Engel AL, Wang Y, Zhu S, Hauer A, Zhang R, Lohner D, Huang J, Dinterman M, Zhao C, Chao JR, Du J. Proline mediates metabolic communication between retinal pigment epithelial cells and the retina. J Biol Chem 2019; 294:10278-10289. [PMID: 31110046 PMCID: PMC6664195 DOI: 10.1074/jbc.ra119.007983] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/16/2019] [Indexed: 01/16/2023] Open
Abstract
The retinal pigment epithelium (RPE) is a monolayer of pigmented cells between the choroid and the retina. RPE dysfunction underlies many retinal degenerative diseases, including age-related macular degeneration, the leading cause of age-related blindness. To perform its various functions in nutrient transport, phagocytosis of the outer segment, and cytokine secretion, the RPE relies on an active energy metabolism. We previously reported that human RPE cells prefer proline as a nutrient and transport proline-derived metabolites to the apical, or retinal, side. In this study, we investigated how RPE utilizes proline in vivo and why proline is a preferred substrate. By using [13C]proline labeling both ex vivo and in vivo, we found that the retina rarely uses proline directly, whereas the RPE utilizes it at a high rate, exporting proline-derived mitochondrial intermediates for use by the retina. We observed that in primary human RPE cell culture, proline is the only amino acid whose uptake increases with cellular maturity. In human RPE, proline was sufficient to stimulate de novo serine synthesis, increase reductive carboxylation, and protect against oxidative damage. Blocking proline catabolism in RPE impaired glucose metabolism and GSH production. Notably, in an acute model of RPE-induced retinal degeneration, dietary proline improved visual function. In conclusion, proline is an important nutrient that supports RPE metabolism and the metabolic demand of the retina.
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Affiliation(s)
- Michelle Yam
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Abbi L Engel
- the Department of Ophthalmology, University of Washington, Seattle, Washington 98109
| | - Yekai Wang
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Siyan Zhu
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Allison Hauer
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Rui Zhang
- From the Departments of Ophthalmology and
- the Save Sight Institute, University of Sydney, 8 Macquarie Street, Sydney, New South Wales 2000, Australia
| | - Daniel Lohner
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Jiancheng Huang
- From the Departments of Ophthalmology and
- the Eye Institute, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China, and
- the Department of Ophthalmology, State Key Laboratory of Reproductive Medicine, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Marlee Dinterman
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Chen Zhao
- the Eye Institute, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China, and
| | - Jennifer R Chao
- the Department of Ophthalmology, University of Washington, Seattle, Washington 98109,
| | - Jianhai Du
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
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34
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Trefts E, Hughey CC, Lantier L, Lark DS, Boyd KL, Pozzi A, Zent R, Wasserman DH. Energy metabolism couples hepatocyte integrin-linked kinase to liver glucoregulation and postabsorptive responses of mice in an age-dependent manner. Am J Physiol Endocrinol Metab 2019; 316:E1118-E1135. [PMID: 30835508 PMCID: PMC6732653 DOI: 10.1152/ajpendo.00496.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Integrin-linked kinase (ILK) is a critical intracellular signaling node for integrin receptors. Its role in liver development is complex, as ILK deletion at E10.5 (before hepatocyte differentiation) results in biochemical and morphological differences that resolve as mice age. Nevertheless, mice with ILK depleted specifically in hepatocytes are protected from the hepatic insulin resistance during obesity. Despite the potential importance of hepatocyte ILK to metabolic health, it is unknown how ILK controls hepatic metabolism or glucoregulation. The present study tested the role of ILK in hepatic metabolism and glucoregulation by deleting it specifically in hepatocytes, using a cre-lox system that begins expression at E15.5 (after initiation of hepatocyte differentiation). These mice develop the most severe morphological and glucoregulatory abnormalities at 6 wk, but these gradually resolve with age. After identifying when the deletion of ILK caused a severe metabolic phenotype, in depth studies were performed at this time point to define the metabolic programs that coordinate control of glucoregulation that are regulated by ILK. We show that 6-wk-old ILK-deficient mice have higher glucose tolerance and decreased net glycogen synthesis. Additionally, ILK was shown to be necessary for transcription of mitochondrial-related genes, oxidative metabolism, and maintenance of cellular energy status. Thus, ILK is required for maintaining hepatic transcriptional and metabolic programs that sustain oxidative metabolism, which are required for hepatic maintenance of glucose homeostasis.
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Affiliation(s)
- Elijah Trefts
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Curtis C Hughey
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Louise Lantier
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
- Mouse Metabolic Phenotyping Center, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Dan S Lark
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Kelli L Boyd
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Ambra Pozzi
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
- Department of Medicine, Vanderbilt University School of Medicine , Nashville, Tennessee
- Veterans Affairs Medical Center , Nashville, Tennessee
| | - Roy Zent
- Department of Medicine, Vanderbilt University School of Medicine , Nashville, Tennessee
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine , Nashville, Tennessee
- Veterans Affairs Medical Center , Nashville, Tennessee
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
- Mouse Metabolic Phenotyping Center, Vanderbilt University School of Medicine , Nashville, Tennessee
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35
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Mignemi NA, McClatchey PM, Kilchrist KV, Williams IM, Millis BA, Syring KE, Duvall CL, Wasserman DH, McGuinness OP. Rapid changes in the microvascular circulation of skeletal muscle impair insulin delivery during sepsis. Am J Physiol Endocrinol Metab 2019; 316:E1012-E1023. [PMID: 30860883 PMCID: PMC6620574 DOI: 10.1152/ajpendo.00501.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 02/21/2019] [Accepted: 03/07/2019] [Indexed: 01/07/2023]
Abstract
Sepsis costs the healthcare system $23 billion annually and has a mortality rate between 10 and 40%. An early indication of sepsis is the onset of hyperglycemia, which is the result of sepsis-induced insulin resistance in skeletal muscle. Previous investigations have focused on events in the myocyte (e.g., insulin signaling and glucose transport and subsequent metabolism) as the causes for this insulin-resistant state. However, the delivery of insulin to the skeletal muscle is also an important determinant of insulin action. Skeletal muscle microvascular blood flow, which delivers the insulin to the muscle, is known to be decreased during sepsis. Here we test whether the reduced capillary blood flow to skeletal muscle belies the sepsis-induced insulin resistance by reducing insulin delivery to the myocyte. We hypothesize that decreased capillary flow and consequent decrease in insulin delivery is an early event that precedes gross cardiovascular alterations seen with sepsis. This hypothesis was examined in mice treated with either lipopolysaccharide (LPS) or polymicrobial sepsis followed by intravital microscopy of the skeletal muscle microcirculation. We calculated insulin delivery to the myocyte using two independent methods and found that LPS and sepsis rapidly reduce insulin delivery to the skeletal muscle by ~50%; this was driven by decreases in capillary flow velocity and the number of perfused capillaries. Furthermore, the changes in skeletal muscle microcirculation occur before changes in both cardiac output and arterial blood pressure. These data suggest that a rapid reduction in skeletal muscle insulin delivery contributes to the induction of insulin resistance during sepsis.
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Affiliation(s)
- Nicholas A Mignemi
- Department of Molecular Physiology and Biophysics, Vanderbilt University , Nashville, Tennessee
| | - P Mason McClatchey
- Department of Molecular Physiology and Biophysics, Vanderbilt University , Nashville, Tennessee
| | - Kameron V Kilchrist
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee
| | - Ian M Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University , Nashville, Tennessee
| | - Bryan A Millis
- Department of Cell and Developmental Biology, Vanderbilt University , Nashville, Tennessee
- Vanderbilt Biophotonics Center, Vanderbilt University , Nashville, Tennessee
| | - Kristen E Syring
- Department of Molecular Physiology and Biophysics, Vanderbilt University , Nashville, Tennessee
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University , Nashville, Tennessee
- Vanderbilt Mouse Metabolic Phenotyping Center , Nashville, Tennessee
| | - Owen P McGuinness
- Department of Molecular Physiology and Biophysics, Vanderbilt University , Nashville, Tennessee
- Vanderbilt Mouse Metabolic Phenotyping Center , Nashville, Tennessee
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36
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E4orf1 protein reduces the need for endogenous insulin. Nutr Diabetes 2019; 9:17. [PMID: 31127081 PMCID: PMC6534626 DOI: 10.1038/s41387-019-0085-x] [Citation(s) in RCA: 5] [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: 01/30/2019] [Revised: 04/30/2019] [Accepted: 05/08/2019] [Indexed: 11/11/2022] Open
Abstract
Background E4orf1 protein derived from adenovirus-36 reduces glucose excursion in mice, and lowers endogenous insulin response, suggesting a reduced need for insulin. We tested if the E4orf1-mediated lowering of insulin response is due to increased tissue sensitivity to insulin, reduced ability to produce or release insulin, or a reduced need for insulin release. Methods Experiment 1: hyperinsulinemic–euglycemic clamps (HEC) and glucose tolerance test (GTT) were performed in high fat fed transgenic mice expressing E4orf1 or non-transgenic littermates (n = 12 each), for 4 weeks. Experiments 2, 3, and 4: E4orf1 or null vectors were expressed in rat-pancreatic β-cell line (INS-1) for 72 h, and cells were exposed to varying levels of glucose. Cell lysates and media were collected. Experiment 5: 3T3L1-preadipocytes that express E4orf1 upon doxycycline induction, or null vector were induced with doxycycline and then exposed to protein transport inhibitor. Supernatant and cell lysate were collected. Experiment 6: 3T3L1-preadipocytes that express E4orf1 upon doxycycline induction, or null vector were co-cultured with INS-1 cells for 24 h. Media was collected. Results Experiment 1: E4orf1 transgenic mice cleared glucose faster compared to non-transgenic mice during GTT. HEC showed that E4orf1 did not alter tissue sensitivity to exogenous insulin in mice. Experiments 2, 3, and 4: in INS1 cells, E4orf1 did not alter Glut2 abundance or Akt activation, suggesting no reduction in glucose sensing or insulin synthesis, respectively. E4orf1 did not influence glucose-stimulated insulin secretion in media by INS1 cells. Experiment 5: E4orf1 was present in cell lysate, but not in media, indicating it is not a secretory protein. Experiment 6: INS1 cells released less insulin in media when co-cultured in the presence of E4orf1-expressing 3T3-L1 cells. Conclusions Our studies support the working hypothesis that the E4orf1-mediated lowering of insulin response is not due to increased tissue sensitivity to insulin, or reduced ability to produce or release insulin, but likely to be due to a reduced need for insulin release.
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Syring KE, Cyphert TJ, Beck TC, Flynn CR, Mignemi NA, McGuinness OP. Systemic bile acids induce insulin resistance in a TGR5-independent manner. Am J Physiol Endocrinol Metab 2019; 316:E782-E793. [PMID: 30779633 PMCID: PMC6732652 DOI: 10.1152/ajpendo.00362.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 02/04/2019] [Accepted: 02/18/2019] [Indexed: 02/07/2023]
Abstract
Bile acids are involved in the emulsification and absorption of dietary fats, as well as acting as signaling molecules. Recently, bile acid signaling through farnesoid X receptor and G protein-coupled bile acid receptor (TGR5) has been reported to elicit changes in not only bile acid synthesis but also metabolic processes, including the alteration of gluconeogenic gene expression and energy expenditure. A role for bile acids in glucose metabolism is also supported by a correlation between changes in the metabolic state of patients (i.e., obesity or postbariatric surgery) and altered serum bile acid levels. However, despite evidence for a role for bile acids during metabolically challenging settings, the direct effect of elevated bile acids on insulin action in the absence of metabolic disease has yet to be investigated. The present study examines the impact of acutely elevated plasma bile acid levels on insulin sensitivity using hyperinsulinemic-euglycemic clamps. In wild-type mice, elevated bile acids impair hepatic insulin sensitivity by blunting the insulin suppression of hepatic glucose production. The impaired hepatic insulin sensitivity could not be attributed to TGR5 signaling, as TGR5 knockout mice exhibited a similar inhibition of insulin suppression of hepatic glucose production. Canonical insulin signaling pathways, such as hepatic PKB (or Akt) activation, were not perturbed in these animals. Interestingly, bile acid infusion directly into the portal vein did not result in an impairment in hepatic insulin sensitivity. Overall, the data indicate that acute increases in circulating bile acids in lean mice impair hepatic insulin sensitivity via an indirect mechanism.
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Affiliation(s)
- Kristen E Syring
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Travis J Cyphert
- Department of Biological Sciences, Marshall University College of Science, Huntington, West Virginia
| | - Thomas C Beck
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Charles R Flynn
- Department of Surgery, Vanderbilt University Medical Center , Nashville, Tennessee
| | - Nicholas A Mignemi
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Owen P McGuinness
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine , Nashville, Tennessee
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Hughey CC, James FD, Wang Z, Goelzer M, Wasserman DH. Dysregulated transmethylation leading to hepatocellular carcinoma compromises redox homeostasis and glucose formation. Mol Metab 2019; 23:1-13. [PMID: 30850319 PMCID: PMC6479583 DOI: 10.1016/j.molmet.2019.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 02/18/2019] [Accepted: 02/20/2019] [Indexed: 12/24/2022] Open
Abstract
Objective The loss of liver glycine N-methyltransferase (GNMT) promotes liver steatosis and the transition to hepatocellular carcinoma (HCC). Previous work showed endogenous glucose production is reduced in GNMT-null mice with gluconeogenic precursors being used in alternative biosynthetic pathways that utilize methyl donors and are linked to tumorigenesis. This metabolic programming occurs before the appearance of HCC in GNMT-null mice. The metabolic physiology that sustains liver tumor formation in GNMT-null mice is unknown. The studies presented here tested the hypothesis that nutrient flux pivots from glucose production to pathways that incorporate and metabolize methyl groups in GNMT-null mice with HCC. Methods 2H/13C metabolic flux analysis was performed in conscious, unrestrained mice lacking GNMT to quantify glucose formation and associated nutrient fluxes. Molecular analyses of livers from mice lacking GNMT including metabolomic, immunoblotting, and immunochemistry were completed to fully interpret the nutrient fluxes. Results GNMT knockout (KO) mice showed lower blood glucose that was accompanied by a reduction in liver glycogenolysis and gluconeogenesis. NAD+ was lower and the NAD(P)H-to-NAD(P)+ ratio was higher in livers of KO mice. Indices of NAD+ synthesis and catabolism, pentose phosphate pathway flux, and glutathione synthesis were dysregulated in KO mice. Conclusion Glucose precursor flux away from glucose formation towards pathways that regulate redox status increase in the liver. Moreover, synthesis and scavenging of NAD+ are both impaired resulting in reduced concentrations. This metabolic program blunts an increase in methyl donor availability, however, biosynthetic pathways underlying HCC are activated. Loss of glycine N-methyltransferase results in hepatocellular carcinoma. Metabolic reprogramming ensues to attenuate the increased S-adenosylmethionine. The metabolic changes include dysregulated liver NAD+ homeostasis and redox state. Liver glucose formation is reduced and precursors directed to biosynthetic pathways.
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Affiliation(s)
- Curtis C Hughey
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN, USA.
| | - Freyja D James
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN, USA; Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN, USA
| | - Zhizhang Wang
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN, USA
| | - Mickael Goelzer
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN, USA
| | - David H Wasserman
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN, USA; Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN, USA
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Tooke BP, Yu H, Adams JM, Jones GL, Sutton-Kennedy T, Mundada L, Qi NR, Low MJ, Chhabra KH. Hypothalamic POMC or MC4R deficiency impairs counterregulatory responses to hypoglycemia in mice. Mol Metab 2018; 20:194-204. [PMID: 30503832 PMCID: PMC6358536 DOI: 10.1016/j.molmet.2018.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/09/2018] [Accepted: 11/14/2018] [Indexed: 11/15/2022] Open
Abstract
Objective Life-threatening hypoglycemia is a major limiting factor in the management of diabetes. While it is known that counterregulatory responses to hypoglycemia are impaired in diabetes, molecular mechanisms underlying the reduced responses remain unclear. Given the established roles of the hypothalamic proopiomelanocortin (POMC)/melanocortin 4 receptor (MC4R) circuit in regulating sympathetic nervous system (SNS) activity and the SNS in stimulating counterregulatory responses to hypoglycemia, we hypothesized that hypothalamic POMC as well as MC4R, a receptor for POMC derived melanocyte stimulating hormones, is required for normal hypoglycemia counterregulation. Methods To test the hypothesis, we induced hypoglycemia or glucopenia in separate cohorts of mice deficient in either POMC or MC4R in the arcuate nucleus (ARC) or the paraventricular nucleus of the hypothalamus (PVH), respectively, and measured their circulating counterregulatory hormones. In addition, we performed a hyperinsulinemic-hypoglycemic clamp study to further validate the function of MC4R in hypoglycemia counterregulation. We also measured Pomc and Mc4r mRNA levels in the ARC and PVH, respectively, in the streptozotocin-induced type 1 diabetes mouse model and non-obese diabetic (NOD) mice to delineate molecular mechanisms by which diabetes deteriorates the defense systems against hypoglycemia. Finally, we treated diabetic mice with the MC4R agonist MTII, administered stereotaxically into the PVH, to determine its potential for restoring the counterregulatory response to hypoglycemia in diabetes. Results Stimulation of epinephrine and glucagon release in response to hypoglycemia or glucopenia was diminished in both POMC- and MC4R-deficient mice, relative to their littermate controls. Similarly, the counterregulatory response was impaired in association with decreased hypothalamic Pomc and Mc4r expression in the diabetic mice, a phenotype that was not reversed by insulin treatment which normalized glycemia. In contrast, infusion of an MC4R agonist in the PVH restored the counterregulatory response in diabetic mice. Conclusion In conclusion, hypothalamic Pomc as well as Mc4r, both of which are reduced in type 1 diabetic mice, are required for normal counterregulatory responses to hypoglycemia. Therefore, enhancing MC4R function may improve hypoglycemia counterregulation in diabetes. Hypothalamic POMC as well as MC4R is necessary to counteract hypoglycemia. Type 1 diabetic mice exhibit a reduced Pomc and Mc4r expression in the hypothalamus. Insulin treatment does not restore Pomc and Mc4r expression in diabetic mice. MC4R agonist improves hypoglycemia counterregulation in diabetic mice.
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Affiliation(s)
- Benjamin P Tooke
- Case Western Reserve University, Cleveland, OH, USA; Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Hui Yu
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jessica M Adams
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Graham L Jones
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Talisha Sutton-Kennedy
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Lakshmi Mundada
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Nathan R Qi
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Malcolm J Low
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Kavaljit H Chhabra
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
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Williams IM, McClatchey PM, Bracy DP, Valenzuela FA, Wasserman DH. Acute Nitric Oxide Synthase Inhibition Accelerates Transendothelial Insulin Efflux In Vivo. Diabetes 2018; 67:1962-1975. [PMID: 30002132 PMCID: PMC6152344 DOI: 10.2337/db18-0288] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 07/03/2018] [Indexed: 12/22/2022]
Abstract
Before insulin can stimulate glucose uptake in muscle, it must be delivered to skeletal muscle (SkM) through the microvasculature. Insulin delivery is determined by SkM perfusion and the rate of movement of insulin across the capillary endothelium. The endothelium therefore plays a central role in regulating insulin access to SkM. Nitric oxide (NO) is a key regulator of endothelial function and stimulates arterial vasodilation, which increases SkM perfusion and the capillary surface area available for insulin exchange. The effects of NO on transendothelial insulin efflux (TIE), however, are unknown. We hypothesized that acute reduction of endothelial NO would reduce TIE. However, intravital imaging of TIE in mice revealed that reduction of NO by l-NG-nitro-l-arginine methyl ester (l-NAME) enhanced the rate of TIE by ∼30% and increased total extravascular insulin delivery. This accelerated TIE was associated with more rapid insulin-stimulated glucose lowering. Sodium nitroprusside, an NO donor, had no effect on TIE in mice. The effects of l-NAME on TIE were not due to changes in blood pressure alone, as a direct-acting vasoconstrictor (phenylephrine) did not affect TIE. These results demonstrate that acute NO synthase inhibition increases the permeability of capillaries to insulin, leading to an increase in delivery of insulin to SkM.
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Affiliation(s)
- Ian M Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - P Mason McClatchey
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Deanna P Bracy
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN
| | | | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN
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Hunter RW, Hughey CC, Lantier L, Sundelin EI, Peggie M, Zeqiraj E, Sicheri F, Jessen N, Wasserman DH, Sakamoto K. Metformin reduces liver glucose production by inhibition of fructose-1-6-bisphosphatase. Nat Med 2018; 24:1395-1406. [PMID: 30150719 PMCID: PMC6207338 DOI: 10.1038/s41591-018-0159-7] [Citation(s) in RCA: 184] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 07/24/2018] [Indexed: 01/03/2023]
Abstract
Metformin is a first-line drug for the treatment of individuals with type 2 diabetes, yet its precise mechanism of action remains unclear. Metformin exerts its antihyperglycemic action primarily through lowering hepatic glucose production (HGP). This suppression is thought to be mediated through inhibition of mitochondrial respiratory complex I, and thus elevation of 5'-adenosine monophosphate (AMP) levels and the activation of AMP-activated protein kinase (AMPK), though this proposition has been challenged given results in mice lacking hepatic AMPK. Here we report that the AMP-inhibited enzyme fructose-1,6-bisphosphatase-1 (FBP1), a rate-controlling enzyme in gluconeogenesis, functions as a major contributor to the therapeutic action of metformin. We identified a point mutation in FBP1 that renders it insensitive to AMP while sparing regulation by fructose-2,6-bisphosphate (F-2,6-P2), and knock-in (KI) of this mutant in mice significantly reduces their response to metformin treatment. We observe this during a metformin tolerance test and in a metformin-euglycemic clamp that we have developed. The antihyperglycemic effect of metformin in high-fat diet-fed diabetic FBP1-KI mice was also significantly blunted compared to wild-type controls. Collectively, we show a new mechanism of action for metformin and provide further evidence that molecular targeting of FBP1 can have antihyperglycemic effects.
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Affiliation(s)
- Roger W Hunter
- Nestlé Institute of Health Sciences SA, Lausanne, Switzerland
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK
| | - Curtis C Hughey
- Department of Molecular Physiology and Biophysics and the Vanderbilt Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN, USA
| | - Louise Lantier
- Department of Molecular Physiology and Biophysics and the Vanderbilt Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN, USA
| | - Elias I Sundelin
- Departments of Clinical Medicine and Biomedicine, Aarhus University, Aarhus, Denmark
| | - Mark Peggie
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK
| | - Elton Zeqiraj
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Frank Sicheri
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
- Departments of Biochemistry and Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Niels Jessen
- Departments of Clinical Medicine and Biomedicine, Aarhus University, Aarhus, Denmark
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics and the Vanderbilt Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN, USA
| | - Kei Sakamoto
- Nestlé Institute of Health Sciences SA, Lausanne, Switzerland.
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Hollenbach M, Klöting N, Sommerer I, Lorenz J, Heindl M, Kern M, Mössner J, Blüher M, Hoffmeister A. p8 deficiency leads to elevated pancreatic beta cell mass but does not contribute to insulin resistance in mice fed with high-fat diet. PLoS One 2018; 13:e0201159. [PMID: 30040846 PMCID: PMC6057664 DOI: 10.1371/journal.pone.0201159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 07/10/2018] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND p8 was initially described as being overexpressed in acute pancreatitis and encoding a ubiquitous stress protein. Analysis of insulin sensitivity and glucose tolerance in p8-knockout and haplodeficient mice revealed counterintuitive results. Thus, we determined glycemic control of p8 in mice fed with standard (SD) and high-fat diet (HFD). METHODS p8-/- and wild type (p8+/+) mice were used for analysis of glucagon (immunohistochemistry), insulin levels (ELISA) and beta cell mass. Hyperinsulinemic- euglycemic glucose clamp technique, i.p. glucose tolerance test (ipGTT), i.p. insulin tolerance test (ipITT) and metabolic chamber analysis were performed in SD (4% fat) and HFD (55% fat) groups. RESULTS p8-/- mice showed no differences in glucagon or insulin content but higher insulin secretion from pancreatic islets upon glucose stimulation. p8 deficiency resulted in elevated beta cell mass but was not associated with increased insulin resistance in ipGTT or ipITT. Glucose clamp tests also revealed no evidence of association of p8 deficiency with insulin resistance. Metabolic chamber analysis showed equal energy expenditure in p8-/- mice and wild type animals. CONCLUSION p8 depletion may contribute to glucose metabolism via stress-induced insulin production and elevated beta cell mass. Nevertheless, p8 knockout showed no impact on insulin resistance in SD and HFD-fed mice.
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Affiliation(s)
- Marcus Hollenbach
- Department of Medicine, Neurology and Dermatology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany
- * E-mail:
| | - Nora Klöting
- IFB Adiposity Disease, University of Leipzig, Leipzig, Germany
| | - Ines Sommerer
- Department of Medicine, Neurology and Dermatology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany
| | - Jana Lorenz
- Department of Medicine, Neurology and Dermatology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany
| | - Mario Heindl
- Department of Medicine, Neurology and Dermatology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany
| | - Matthias Kern
- German Diabetes Center Leipzig, University of Leipzig, Leipzig, Germany
| | - Joachim Mössner
- Department of Medicine, Neurology and Dermatology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany
| | - Matthias Blüher
- Department of Medicine, Neurology and Dermatology, Division of Endocrinology and Nephrology, University of Leipzig, Leipzig, Germany
| | - Albrecht Hoffmeister
- Department of Medicine, Neurology and Dermatology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany
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McClatchey PM, Mignemi NA, Xu Z, Williams IM, Reusch JEB, McGuinness OP, Wasserman DH. Automated quantification of microvascular perfusion. Microcirculation 2018; 25:e12482. [PMID: 29908041 DOI: 10.1111/micc.12482] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 06/11/2018] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Changes in microvascular perfusion have been reported in many diseases, yet the functional significance of altered perfusion is often difficult to determine. This is partly because commonly used techniques for perfusion measurement often rely on either indirect or by-hand approaches. METHODS We developed and validated a fully automated software technique to measure microvascular perfusion in videos acquired by fluorescence microscopy in the mouse gastrocnemius. Acute perfusion responses were recorded following intravenous injections with phenylephrine, SNP, or saline. RESULTS Software-measured capillary flow velocity closely correlated with by-hand measured flow velocity (R2 = 0.91, P < 0.0001). Software estimates of capillary hematocrit also generally agreed with by-hand measurements (R2 = 0.64, P < 0.0001). Detection limits range from 0 to 2000 μm/s, as compared to an average flow velocity of 326 ± 102 μm/s (mean ± SD) at rest. SNP injection transiently increased capillary flow velocity and hematocrit and made capillary perfusion more steady and homogenous. Phenylephrine injection had the opposite effect in all metrics. Saline injection transiently decreased capillary flow velocity and hematocrit without influencing flow distribution or stability. All perfusion metrics were temporally stable without intervention. CONCLUSIONS These results demonstrate a novel and sensitive technique for reproducible, user-independent quantification of microvascular perfusion.
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Affiliation(s)
- Penn Mason McClatchey
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Nicholas A Mignemi
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Zhengang Xu
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Ian M Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Jane E B Reusch
- Division of Endocrinology, University of Colorado Medical School, Aurora, Colorado.,Department of Bioengineering, University of Colorado Denver, Denver, Colorado.,Department of Veterans Affairs, Aurora, Colorado
| | - Owen P McGuinness
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee.,Mouse Metabolic Phenotyping Center, Nashville, Tennessee
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee.,Mouse Metabolic Phenotyping Center, Nashville, Tennessee
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Hughey CC, Trefts E, Bracy DP, James FD, Donahue EP, Wasserman DH. Glycine N-methyltransferase deletion in mice diverts carbon flux from gluconeogenesis to pathways that utilize excess methionine cycle intermediates. J Biol Chem 2018; 293:11944-11954. [PMID: 29891549 DOI: 10.1074/jbc.ra118.002568] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/17/2018] [Indexed: 12/19/2022] Open
Abstract
Glycine N-methyltransferase (GNMT) is the most abundant liver methyltransferase regulating the availability of the biological methyl donor, S-adenosylmethionine (SAM). Moreover, GNMT has been identified to be down-regulated in hepatocellular carcinoma (HCC). Despite its role in regulating SAM levels and association of its down-regulation with liver tumorigenesis, the impact of reduced GNMT on metabolic reprogramming before the manifestation of HCC has not been investigated in detail. Herein, we used 2H/13C metabolic flux analysis in conscious, unrestrained mice to test the hypothesis that the absence of GNMT causes metabolic reprogramming. GNMT-null (KO) mice displayed a reduction in blood glucose that was associated with a decline in both hepatic glycogenolysis and gluconeogenesis. The reduced gluconeogenesis was due to a decrease in liver gluconeogenic precursors, citric acid cycle fluxes, and anaplerosis and cataplerosis. A concurrent elevation in both hepatic SAM and metabolites of SAM utilization pathways was observed in the KO mice. Specifically, the increase in metabolites of SAM utilization pathways indicated that hepatic polyamine synthesis and catabolism, transsulfuration, and de novo lipogenesis pathways were increased in the KO mice. Of note, these pathways utilize substrates that could otherwise be used for gluconeogenesis. Also, this metabolic reprogramming occurs before the well-documented appearance of HCC in GNMT-null mice. Together, these results indicate that GNMT deletion promotes a metabolic shift whereby nutrients are channeled away from glucose formation toward pathways that utilize the elevated SAM.
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Affiliation(s)
- Curtis C Hughey
- From the Department of Molecular Physiology and Biophysics and
| | - Elijah Trefts
- From the Department of Molecular Physiology and Biophysics and
| | - Deanna P Bracy
- From the Department of Molecular Physiology and Biophysics and.,the Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, Tennessee 37232
| | - Freyja D James
- From the Department of Molecular Physiology and Biophysics and.,the Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, Tennessee 37232
| | | | - David H Wasserman
- From the Department of Molecular Physiology and Biophysics and.,the Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, Tennessee 37232
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Schönke M, Massart J, Zierath JR. Effects of high-fat diet and AMP-activated protein kinase modulation on the regulation of whole-body lipid metabolism. J Lipid Res 2018; 59:1276-1282. [PMID: 29739863 DOI: 10.1194/jlr.d082370] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 04/06/2018] [Indexed: 12/17/2022] Open
Abstract
Metabolic flexibility, the capacity to adapt to fuel availability for energy production, is crucial for maintaining whole-body energy homeostasis. An inability to adequately promote FA utilization is associated with lipid accumulation in peripheral tissues and contributes to the development of insulin resistance. In vivo assays to quantify whole-body lipid oxidation in mouse models of insulin resistance are lacking. We describe a method for assessing whole-body FA oxidation in vivo, as well as tissue-specific lipid uptake in conscious mice. The method relies on intravenous administration of [9,10-3H(N)]palmitic acid combined with a non-β-oxidizable palmitate analog, [1-14C]2-bromopalmitic acid. Pretreatment with etomoxir, a CPT1 inhibitor that prevents the shuttling of FAs into mitochondria, markedly reduced the appearance of the β-oxidation product 3H2O in circulation and reduced lipid uptake by oxidative tissues including heart and soleus muscle. Whole-body fatty oxidation was unaltered between chow- or high-fat-fed WT and transgenic mice expressing a mutant form of the AMPK γ3 subunit (AMPKγ3R225Q) in skeletal muscle. High-fat feeding increased lipid oxidation in WT and AMPKγ3R225Q transgenic mice. In conclusion, this technique allows for the assessment of the effect of pharmaceutical agents, as well as gene mutations, on whole-body FA oxidation in mice.
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Affiliation(s)
- Milena Schönke
- Department of Molecular Medicine and Surgery Karolinska Institutet, Stockholm, Sweden
| | - Julie Massart
- Department of Molecular Medicine and Surgery Karolinska Institutet, Stockholm, Sweden
| | - Juleen R Zierath
- Department of Molecular Medicine and Surgery Karolinska Institutet, Stockholm, Sweden .,Department of Physiology and Pharmacology, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
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Zhang Y, Xu L, Liu X, Wang Y. Evaluation of insulin sensitivity by hyperinsulinemic-euglycemic clamps using stable isotope-labeled glucose. Cell Discov 2018; 4:17. [PMID: 29675266 PMCID: PMC5902507 DOI: 10.1038/s41421-018-0016-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 01/24/2018] [Indexed: 01/01/2023] Open
Affiliation(s)
- Yuanyuan Zhang
- 1MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Lina Xu
- 2National Protein Science Technology Center, Tsinghua University, Beijing, 100084 China
| | - Xiaohui Liu
- 2National Protein Science Technology Center, Tsinghua University, Beijing, 100084 China
| | - Yiguo Wang
- 1MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084 China
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47
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Membrane Trafficking Protein CDP138 Regulates Fat Browning and Insulin Sensitivity through Controlling Catecholamine Release. Mol Cell Biol 2018; 38:MCB.00153-17. [PMID: 29378832 DOI: 10.1128/mcb.00153-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 01/15/2018] [Indexed: 01/22/2023] Open
Abstract
CDP138 is a calcium- and lipid-binding protein that is involved in membrane trafficking. Here, we report that mice without CDP138 develop obesity under normal chow diet (NCD) or high-fat diet (HFD) conditions. CDP138-/- mice have lower energy expenditure, oxygen consumption, and body temperature than wild-type (WT) mice. CDP138 is exclusively expressed in adrenal medulla and is colocalized with tyrosine hydroxylase (TH), a marker of sympathetic nervous terminals, in the inguinal fat. Compared with WT controls, CDP138-/- mice had altered catecholamine levels in circulation, adrenal gland, and inguinal fat. Adrenergic signaling on cyclic AMP (cAMP) formation and hormone-sensitive lipase (HSL) phosphorylation induced by cold challenge but not by an exogenous β3 adrenoceptor against CL316243 were decreased in adipose tissues of CDP138-/- mice. Cold-induced beige fat browning, fatty acid oxidation, thermogenesis, and related gene expression were reduced in CDP138-/- mice. CDP138-/- mice are also prone to HFD-induced insulin resistance, as assessed by Akt phosphorylation and glucose transport in skeletal muscles. Our data indicate that CDP138 is a regulator of stress response and plays a significant role in adipose tissue browning, energy balance, and insulin sensitivity through regulating catecholamine secretion from the sympathetic nervous terminals and adrenal gland.
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48
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Rossi M, Zhu L, McMillin SM, Pydi SP, Jain S, Wang L, Cui Y, Lee RJ, Cohen AH, Kaneto H, Birnbaum MJ, Ma Y, Rotman Y, Liu J, Cyphert TJ, Finkel T, McGuinness OP, Wess J. Hepatic Gi signaling regulates whole-body glucose homeostasis. J Clin Invest 2018; 128:746-759. [PMID: 29337301 PMCID: PMC5785257 DOI: 10.1172/jci94505] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 11/17/2017] [Indexed: 01/12/2023] Open
Abstract
An increase in hepatic glucose production (HGP) is a key feature of type 2 diabetes. Excessive signaling through hepatic Gs-linked glucagon receptors critically contributes to pathologically elevated HGP. Here, we tested the hypothesis that this metabolic impairment can be counteracted by enhancing hepatic Gi signaling. Specifically, we used a chemogenetic approach to selectively activate Gi-type G proteins in mouse hepatocytes in vivo. Unexpectedly, activation of hepatic Gi signaling triggered a pronounced increase in HGP and severely impaired glucose homeostasis. Moreover, increased Gi signaling stimulated glucose release in human hepatocytes. A lack of functional Gi-type G proteins in hepatocytes reduced blood glucose levels and protected mice against the metabolic deficits caused by the consumption of a high-fat diet. Additionally, we delineated a signaling cascade that links hepatic Gi signaling to ROS production, JNK activation, and a subsequent increase in HGP. Taken together, our data support the concept that drugs able to block hepatic Gi-coupled GPCRs may prove beneficial as antidiabetic drugs.
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Affiliation(s)
- Mario Rossi
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
| | - Lu Zhu
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
| | - Sara M. McMillin
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
| | - Sai Prasad Pydi
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
| | - Shanu Jain
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
| | - Lei Wang
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
| | - Yinghong Cui
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
| | - Regina J. Lee
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
| | - Amanda H. Cohen
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
| | - Hideaki Kaneto
- Osaka University Graduate School of Medicine, Osaka, Japan
| | - Morris J. Birnbaum
- Cardiovascular and Metabolic Diseases (CVMED), Pfizer Inc., Cambridge, Massachusetts, USA
| | - Yanling Ma
- Liver and Energy Metabolism Unit, Liver Diseases Branch, NIDDK, Bethesda, Maryland, USA
| | - Yaron Rotman
- Liver and Energy Metabolism Unit, Liver Diseases Branch, NIDDK, Bethesda, Maryland, USA
| | - Jie Liu
- Center for Molecular Medicine, National Heart, Lung, and Blood Institute (NHLBI), Bethesda, Maryland, USA
| | - Travis J. Cyphert
- Departments of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Toren Finkel
- Center for Molecular Medicine, National Heart, Lung, and Blood Institute (NHLBI), Bethesda, Maryland, USA
| | - Owen P. McGuinness
- Departments of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jürgen Wess
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
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49
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Williams IM, Valenzuela FA, Kahl SD, Ramkrishna D, Mezo AR, Young JD, Wells KS, Wasserman DH. Insulin exits skeletal muscle capillaries by fluid-phase transport. J Clin Invest 2018; 128:699-714. [PMID: 29309051 DOI: 10.1172/jci94053] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 11/14/2017] [Indexed: 12/12/2022] Open
Abstract
Before insulin can stimulate myocytes to take up glucose, it must first move from the circulation to the interstitial space. The continuous endothelium of skeletal muscle (SkM) capillaries restricts insulin's access to myocytes. The mechanism by which insulin crosses this continuous endothelium is critical to understand insulin action and insulin resistance; however, methodological obstacles have limited understanding of endothelial insulin transport in vivo. Here, we present an intravital microscopy technique to measure the rate of insulin efflux across the endothelium of SkM capillaries. This method involves development of a fully bioactive, fluorescent insulin probe, a gastrocnemius preparation for intravital microscopy, an automated vascular segmentation algorithm, and the use of mathematical models to estimate endothelial transport parameters. We combined direct visualization of insulin efflux from SkM capillaries with modeling of insulin efflux kinetics to identify fluid-phase transport as the major mode of transendothelial insulin efflux in mice. Model-independent experiments demonstrating that insulin movement is neither saturable nor affected by insulin receptor antagonism supported this result. Our finding that insulin enters the SkM interstitium by fluid-phase transport may have implications in the pathophysiology of SkM insulin resistance as well as in the treatment of diabetes with various insulin analogs.
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Affiliation(s)
- Ian M Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Steven D Kahl
- Lilly Research Laboratories, Indianapolis, Indiana, USA
| | | | - Adam R Mezo
- Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Jamey D Young
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA.,Department of Chemical and Biomolecular Engineering, and.,Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, Tennessee, USA
| | - K Sam Wells
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA.,Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, Tennessee, USA
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA.,Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, Tennessee, USA
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50
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Valitsky M, Hoffman A, Unterman T, Bar-Tana J. Insulin sensitizer prevents and ameliorates experimental type 1 diabetes. Am J Physiol Endocrinol Metab 2017; 313:E672-E680. [PMID: 28270441 DOI: 10.1152/ajpendo.00329.2016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 02/27/2017] [Accepted: 03/01/2017] [Indexed: 01/12/2023]
Abstract
Insulin-dependent type-1 diabetes (T1D) is driven by autoimmune β-cell failure, whereas systemic resistance to insulin is considered the hallmark of insulin-independent type-2 diabetes (T2D). In contrast to this canonical dichotomy, insulin resistance appears to precede the overt diabetic stage of T1D and predict its progression, implying that insulin sensitizers may change the course of T1D. However, previous attempts to ameliorate T1D in animal models or patients by insulin sensitizers have largely failed. Sensitization to insulin by MEthyl-substituted long-chain DICArboxylic acid (MEDICA) analogs in T2D animal models surpasses that of current insulin sensitizers, thus prompting our interest in probing MEDICA in the T1D context. MEDICA efficacy in modulating the course of T1D was verified in streptozotocin (STZ) diabetic rats and autoimmune nonobese diabetic (NOD) mice. MEDICA treatment normalizes overt diabetes in STZ diabetic rats when added on to subtherapeutic insulin, and prevents/delays autoimmune T1D in NOD mice. MEDICA treatment does not improve β-cell insulin content or insulitis score, but its efficacy is accounted for by pronounced total body sensitization to insulin. In conclusion, potent insulin sensitizers may counteract genetic predisposition to autoimmune T1D and amplify subtherapeutic insulin into an effective therapeutic measure for the treatment of overt T1D.
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Affiliation(s)
- Michael Valitsky
- Department of Human Nutrition and Metabolism, Hebrew University Medical School, Jerusalem, Israel
| | - Amnon Hoffman
- Institute for Drug Research, Hebrew University Faculty of Medicine, Jerusalem, Israel; and
| | - Terry Unterman
- Section of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois
| | - Jacob Bar-Tana
- Department of Human Nutrition and Metabolism, Hebrew University Medical School, Jerusalem, Israel;
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