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Coate KC, Ramnanan CJ, Smith M, Winnick JJ, Kraft G, Irimia-Dominguez J, Farmer B, Donahue EP, Roach PJ, Cherrington AD, Edgerton DS. Integration of metabolic flux with hepatic glucagon signaling and gene expression profiles in the conscious dog. Am J Physiol Endocrinol Metab 2024; 326:E428-E442. [PMID: 38324258 PMCID: PMC11193521 DOI: 10.1152/ajpendo.00316.2023] [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: 09/25/2023] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/08/2024]
Abstract
Glucagon rapidly and profoundly stimulates hepatic glucose production (HGP), but for reasons that are unclear, this effect normally wanes after a few hours, despite sustained plasma glucagon levels. This study characterized the time course of glucagon-mediated molecular events and their relevance to metabolic flux in the livers of conscious dogs. Glucagon was either infused into the hepato-portal vein at a sixfold basal rate in the presence of somatostatin and basal insulin, or it was maintained at a basal level in control studies. In one control group, glucose remained at basal, whereas in the other, glucose was infused to match the hyperglycemia that occurred in the hyperglucagonemic group. Elevated glucagon caused a rapid (30 min) and largely sustained increase in hepatic cAMP over 4 h, a continued elevation in glucose-6-phosphate (G6P), and activation and deactivation of glycogen phosphorylase and synthase activities, respectively. Net hepatic glycogenolysis increased rapidly, peaking at 15 min due to activation of the cAMP/PKA pathway, then slowly returned to baseline over the next 3 h in line with allosteric inhibition by glucose and G6P. Glucagon's stimulatory effect on HGP was sustained relative to the hyperglycemic control group due to continued PKA activation. Hepatic gluconeogenic flux did not increase due to the lack of glucagon's effect on substrate supply to the liver. Global gene expression profiling highlighted glucagon-regulated activation of genes involved in cellular respiration, metabolic processes, and signaling, as well as downregulation of genes involved in extracellular matrix assembly and development.NEW & NOTEWORTHY Glucagon rapidly stimulates hepatic glucose production, but these effects are transient. This study links the molecular and metabolic flux changes that occur in the liver over time in response to a rise in glucagon, demonstrating the strength of the dog as a translational model to couple findings in small animals and humans. In addition, this study clarifies why the rapid effects of glucagon on liver glycogen metabolism are not sustained.
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Affiliation(s)
- Katie C Coate
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Christopher J Ramnanan
- Department of Innovation in Medical Education, University of Ottawa Faculty of Medicine, Ottawa, Ontario, Canada
| | - Marta Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Jason J Winnick
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
| | - Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Jose Irimia-Dominguez
- Department of Molecular and Cellular Endocrinology, Beckman Research Institute, Duarte, California, United States
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - E Patrick Donahue
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Peter J Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
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Yen CL, Petrie MA, Suneja M, Shields RK. Neuromuscular and gene signaling responses to passive whole-body heat stress in young adults. J Therm Biol 2023; 118:103730. [PMID: 37890230 DOI: 10.1016/j.jtherbio.2023.103730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 09/13/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023]
Abstract
This study aimed to investigate whether acute passive heat stress 1) decreases muscle Maximal Voluntary Contraction (MVC); 2) increases peripheral muscle fatigue; 3) increases spinal cord excitability, and 4) increases key skeletal muscle gene signaling pathways in skeletal muscle. Examining the biological and physiological markers underlying passive heat stress will assist us in understanding the potential therapeutic benefits. MVCs, muscle fatigue, spinal cord excitability, and gene signaling were examined after control or whole body heat stress in an environmental chamber (heat; 82 °C, 10% humidity for 30 min). Heart Rate (HR), an indicator of stress response, was correlated to muscle fatigue in the heat group (R = 0.59; p < 0.05) but was not correlated to MVC, twitch potentiation, and H reflex suppression. Sixty-one genes were differentially expressed after heat (41 genes >1.5-fold induced; 20 < 0.667 fold repressed). A strong correlation emerged between the session type (control or heat) and principal components (PC1) (R = 0.82; p < 0.005). Cell Signal Transduction, Metabolism, Gene Expression and Transcription, Immune System, DNA Repair, and Metabolism of Proteins were pathway domains with the largest number of genes regulated after acute whole body heat stress. Acute whole-body heat stress may offer a physiological stimulus for people with a limited capacity to exercise.
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Affiliation(s)
- Chu-Ling Yen
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Chang Gung Memorial Hospital, Neuroscience Research Center, Linkou, Taoyuan, Taiwan
| | - Michael A Petrie
- Department of Physical Therapy and Rehabilitation Science, Roy and Lucille Carver College of Medicine, The University of Iowa, Medical Education Building, Iowa City, IA, USA
| | - Manish Suneja
- Department of Internal Medicine, Roy and Lucille Carver College of Medicine, The University of Iowa, Iowa City, IA, USA
| | - Richard K Shields
- Department of Physical Therapy and Rehabilitation Science, Roy and Lucille Carver College of Medicine, The University of Iowa, Medical Education Building, Iowa City, IA, USA.
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Coate KC, Ramnanan CJ, Smith M, Winnick JJ, Kraft G, Irimia JM, Farmer B, Donahue P, Roach PJ, Cherrington AD, Edgerton DS. Integration of metabolic flux with hepatic glucagon signaling and gene expression profiles in the conscious dog. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.28.559999. [PMID: 37808670 PMCID: PMC10557670 DOI: 10.1101/2023.09.28.559999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Glucagon rapidly and profoundly simulates hepatic glucose production (HGP), but for reasons which are unclear, this effect normally wanes after a few hours, despite sustained plasma glucagon levels. This study characterized the time course and relevance (to metabolic flux) of glucagon mediated molecular events in the livers of conscious dogs. Glucagon was either infused into the hepato-portal vein at a 6-fold basal rate in the presence of somatostatin and basal insulin, or it was maintained at a basal level in control studies. In one control group glucose remained at basal while in the other glucose was infused to match the hyperglycemia that occurred in the hyperglucagonemic group. Elevated glucagon caused a rapid (30 min) but only partially sustained increase in hepatic cAMP over 4h, a continued elevation in G6P, and activation and deactivation of glycogen phosphorylase and synthase activities, respectively. Net hepatic glycogenolysis and HGP increased rapidly, peaking at 30 min, then returned to baseline over the next 3h (although glucagons stimulatory effect on HGP was sustained relative to the hyperglycemic control group). Hepatic gluconeogenic flux did not increase due to lack of glucagon effect on substrate supply to the liver. Global gene expression profiling highlighted glucagon-regulated activation of genes involved in cellular respiration, metabolic processes, and signaling, and downregulation of genes involved in extracellular matrix assembly and development.
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Nyberg M, Terzic D, Ludvigsen TP, Mark PD, Michaelsen NB, Abildstrøm SZ, Engelmann M, Richards AM, Goetze JP. Review A State of Natriuretic Peptide Deficiency. Endocr Rev 2022; 44:379-392. [PMID: 36346821 PMCID: PMC10166265 DOI: 10.1210/endrev/bnac029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/13/2022] [Accepted: 11/04/2022] [Indexed: 11/10/2022]
Abstract
Measurement of natriuretic peptides (NPs) has proven its clinical value as biomarker, especially in the context of heart failure (HF). In contrast, a state partial NP deficiency appears integral to several conditions in which lower NP concentrations in plasma presage overt cardiometabolic disease. Here, obesity and type 2 diabetes have attracted considerable attention. Other factors - including age, sex, race, genetics, and diurnal regulation - affect the NP "armory" and may leave some individuals more prone to development of cardiovascular disease. The molecular maturation of NPs has also proven complex with highly variable O-glycosylation within the biosynthetic precursors. The relevance of this regulatory step in post-translational propeptide maturation has recently become recognized in biomarker measurement/interpretation and cardiovascular pathophysiology. An important proportion of people appear to have reduced effective net NP bioactivity in terms of receptor activation and physiological effects. The state of NP deficiency, then, both entails a potential for further biomarker development and could also offer novel pharmacological possibilities. Alleviating the state of NP deficiency before development of overt cardiometabolic disease in selected patients could be a future path for improving precision medicine.
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Affiliation(s)
| | - Dijana Terzic
- Department of Clinical Biochemistry, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | | | - Peter D Mark
- Department of Clinical Biochemistry, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | | | | | | | - A Mark Richards
- Division of Cardiology, National University Heart Centre, National University Hospital, Singapore
| | - Jens P Goetze
- Department of Clinical Biochemistry, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health, Copenhagen University, Copenhagen, Denmark
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Gregory JM, Kraft G, Farmer B, Smith MS, LaNeve DC, Williams PE, Tomasek K, Su YR, Wilson CS, Thompson MD, Cherrington AD, Coate KC. Insulin Infusion Is Linked to Increased NPPC Expression in Muscle and Plasma C-type Natriuretic Peptide in Male Dogs. J Endocr Soc 2021; 5:bvab088. [PMID: 34131611 PMCID: PMC8195255 DOI: 10.1210/jendso/bvab088] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Indexed: 11/19/2022] Open
Abstract
The purpose of this study was to assess insulin-stimulated gene expression in canine skeletal muscle with a particular focus on NPPC, the gene that encodes C-type natriuretic peptide, a key hormonal regulator of cardiometabolic function. Four conscious canines underwent hyperinsulinemic, euglycemic clamp studies. Skeletal muscle biopsy and arterial plasma samples were collected under basal and insulin-stimulated conditions. Bulk RNA sequencing of muscle tissue was performed to identify differentially expressed genes between these 2 steady-state conditions. Our results showed that NPPC was the most highly expressed gene in skeletal muscle in response to insulin infusion, rising 4-fold between basal and insulin-stimulated conditions. In support of our RNA sequencing data, we found that raising the plasma insulin concentration 15-fold above basal elicited a 2-fold (P = 0.0001) increase in arterial plasma concentrations of N-terminal prohormone C-type natriuretic peptide. Our data suggest that insulin may play a role in stimulating secretion of C-type natriuretic peptide by skeletal muscle. In this context, C-type natriuretic peptide may act in a paracrine manner to facilitate muscle–vascular bed crosstalk and potentiate insulin-mediated vasodilation. This could serve to enhance insulin and glucose delivery, particularly in the postprandial absorptive state.
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Affiliation(s)
- Justin M Gregory
- Ian M. Burr Division of Pediatric Endocrinology and Diabetes, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Marta S Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - David C LaNeve
- Section of Surgical Sciences, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Phillip E Williams
- Section of Surgical Sciences, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kelsey Tomasek
- Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Yan Ru Su
- Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Christopher S Wilson
- Ian M. Burr Division of Pediatric Endocrinology and Diabetes, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | | | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Katie C Coate
- Division of Diabetes, Endocrinology, & Metabolism, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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