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Groeger M, Matsuo K, Heidary Arash E, Pereira A, Le Guillou D, Pino C, Telles-Silva KA, Maher JJ, Hsiao EC, Willenbring H. Modeling and therapeutic targeting of inflammation-induced hepatic insulin resistance using human iPSC-derived hepatocytes and macrophages. Nat Commun 2023; 14:3902. [PMID: 37400454 PMCID: PMC10318012 DOI: 10.1038/s41467-023-39311-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 06/07/2023] [Indexed: 07/05/2023] Open
Abstract
Hepatic insulin resistance is recognized as a driver of type 2 diabetes and fatty liver disease but specific therapies are lacking. Here we explore the potential of human induced pluripotent stem cells (iPSCs) for modeling hepatic insulin resistance in vitro, with a focus on resolving the controversy about the impact of inflammation in the absence of steatosis. For this, we establish the complex insulin signaling cascade and the multiple inter-dependent functions constituting hepatic glucose metabolism in iPSC-derived hepatocytes (iPSC-Heps). Co-culture of these insulin-sensitive iPSC-Heps with isogenic iPSC-derived pro-inflammatory macrophages induces glucose output by preventing insulin from inhibiting gluconeogenesis and glycogenolysis and activating glycolysis. Screening identifies TNFα and IL1β as the mediators of insulin resistance in iPSC-Heps. Neutralizing these cytokines together restores insulin sensitivity in iPSC-Heps more effectively than individual inhibition, reflecting specific effects on insulin signaling and glucose metabolism mediated by NF-κB or JNK. These results show that inflammation is sufficient to induce hepatic insulin resistance and establish a human iPSC-based in vitro model to mechanistically dissect and therapeutically target this metabolic disease driver.
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Affiliation(s)
- Marko Groeger
- Division of Transplant Surgery, Department of Surgery, University of California San Francisco, San Francisco, CA, 94143, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Koji Matsuo
- Division of Endocrinology and Metabolism, Department of Medicine, University of California San Francisco, San Francisco, CA, 94143, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Emad Heidary Arash
- Division of Transplant Surgery, Department of Surgery, University of California San Francisco, San Francisco, CA, 94143, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Ashley Pereira
- Division of Endocrinology and Metabolism, Department of Medicine, University of California San Francisco, San Francisco, CA, 94143, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Dounia Le Guillou
- Division of Gastroenterology, Department of Medicine, University of California San Francisco, San Francisco, CA, 94143, USA
- Liver Center, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Cindy Pino
- Liver Center, University of California San Francisco, San Francisco, CA, 94143, USA
- Genomics CoLab, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Kayque A Telles-Silva
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA, 94143, USA
- Human Genome and Stem Cell Research Center, University of Sao Paulo, 05508-090, Sao Paulo, Brazil
| | - Jacquelyn J Maher
- Division of Gastroenterology, Department of Medicine, University of California San Francisco, San Francisco, CA, 94143, USA
- Liver Center, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Edward C Hsiao
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA, 94143, USA
- Division of Endocrinology and Metabolism, Department of Medicine, University of California San Francisco, San Francisco, CA, 94143, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Holger Willenbring
- Division of Transplant Surgery, Department of Surgery, University of California San Francisco, San Francisco, CA, 94143, USA.
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA, 94143, USA.
- Liver Center, University of California San Francisco, San Francisco, CA, 94143, USA.
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Miller CO, Cao J. Probing Hepatic Glucose Metabolism via 13C NMR Spectroscopy in Perfused Livers-Applications to Drug Development. Metabolites 2021; 11:metabo11110712. [PMID: 34822370 PMCID: PMC8622237 DOI: 10.3390/metabo11110712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 11/23/2022] Open
Abstract
Despite being first published over 40 years ago, the combination of 13C nuclear magnetic resonance spectroscopy (NMR) and the isolated perfused liver preparation remains a unique and relevant approach in investigating the effects of pharmacological interventions on hepatic metabolism. The use of intact, perfused livers maintains many metabolic reactions at their respective rates in vivo, while the use of 13C-labelled substrates in combination with 13C NMR allows for a detailed study of specific pathways, as well as the design of robust assays which can be used to evaluate novel pharmacological agents. In this review article, we share some of the methods used to probe glucose metabolism, and highlight key findings and successes derived from the application of this specialized technique to the area of drug development for diabetes and related metabolic disorders.
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Warner SO, Wadian AM, Smith M, Farmer B, Dai Y, Sheanon N, Edgerton DS, Winnick JJ. Liver glycogen-induced enhancements in hypoglycemic counterregulation require neuroglucopenia. Am J Physiol Endocrinol Metab 2021; 320:E914-E924. [PMID: 33779306 PMCID: PMC8424545 DOI: 10.1152/ajpendo.00501.2020] [Citation(s) in RCA: 3] [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: 10/13/2020] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 01/24/2023]
Abstract
Iatrogenic hypoglycemia is a prominent barrier to achieving optimal glycemic control in patients with diabetes, in part due to dampened counterregulatory hormone responses. It has been demonstrated that elevated liver glycogen content can enhance these hormonal responses through signaling to the brain via afferent nerves, but the role that hypoglycemia in the brain plays in this liver glycogen effect remains unclear. During the first 4 h of each study, the liver glycogen content of dogs was increased by using an intraportal infusion of fructose to stimulate hepatic glucose uptake (HG; n = 13), or glycogen was maintained near fasting levels with a saline infusion (NG; n = 6). After a 2-h control period, during which the fructose/saline infusion was discontinued, insulin was infused intravenously for an additional 2 h to bring about systemic hypoglycemia in all animals, whereas brain euglycemia was maintained in a subset of the HG group by infusing glucose bilaterally into the carotid and vertebral arteries (HG-HeadEu; n = 7). Liver glycogen content was markedly elevated in the two HG groups (43 ± 4, 73 ± 3, and 75 ± 7 mg/g in NG, HG, and HG-HeadEu, respectively). During the hypoglycemic period, arterial plasma glucose levels were indistinguishable between groups (53 ± 2, 52 ± 1, and 51 ± 1 mg/dL, respectively), but jugular vein glucose levels were kept euglycemic (88 ± 5 mg/dL) only in the HG-HeadEu group. Glucagon and epinephrine responses to hypoglycemia were higher in HG compared with NG, whereas despite the increase in liver glycogen, neither increased above basal in HG-HeadEu. These data demonstrate that the enhanced counterregulatory hormone secretion that accompanies increased liver glycogen content requires hypoglycemia in the brain.NEW & NOTEWORTHY It is well known that iatrogenic hypoglycemia is a barrier to optimal glycemic regulation in patients with diabetes. Our data confirm that increasing liver glycogen content 75% above fasting levels enhances hormonal responses to insulin-induced hypoglycemia and demonstrate that this enhanced hormonal response does not occur in the absence of hypoglycemia in the brain. These data demonstrate that information from the liver regarding glycogen availability is integrated in the brain to optimize the counterregulatory response.
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Affiliation(s)
- Shana O Warner
- Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Abby M Wadian
- Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Marta Smith
- Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Ben Farmer
- Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Yufei Dai
- Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Nicole Sheanon
- Department of Endocrinology, University of Cincinnati College of Medicine and Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Dale S Edgerton
- Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Jason J Winnick
- Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
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Sun HJ, Wu ZY, Nie XW, Bian JS. The Role of H 2S in the Metabolism of Glucose and Lipids. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1315:51-66. [PMID: 34302688 DOI: 10.1007/978-981-16-0991-6_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Glucose and lipids are essential elements for maintaining the body's homeostasis, and their dysfunction may participate in the pathologies of various diseases, particularly diabetes, obesity, metabolic syndrome, cardiovascular ailments, and cancers. Among numerous endogenous mediators, the gasotransmitter hydrogen sulfide (H2S) plays a central role in the maintenance of glucose and lipid homeostasis. Current evidence from both pharmacological studies and transgenic animal models suggest a complex relationship between H2S and metabolic dysregulation, especially in diabetes and obesity. This notion is achieved through tissue-specific expressions and actions of H2S on target metabolic and hormone organs including the pancreas, skeletal muscle, livers, and adipose. In this chapter, we will summarize the roles and mechanisms of H2S in several metabolic organs/tissues that are necessary for glucose and lipid metabolic homeostasis. In addition, future research directions and valuable therapeutic avenues around the pharmacological regulation of H2S in glycolipid metabolism disorder will be also discussed.
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Affiliation(s)
- Hai-Jian Sun
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Zhi-Yuan Wu
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Xiao-Wei Nie
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Center of Clinical Research, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China
| | - Jin-Song Bian
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. .,National University of Singapore (Suzhou) Research Institute, Suzhou, China.
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Warner SO, Yao MV, Cason RL, Winnick JJ. Exercise-Induced Improvements to Whole Body Glucose Metabolism in Type 2 Diabetes: The Essential Role of the Liver. Front Endocrinol (Lausanne) 2020; 11:567. [PMID: 32982968 PMCID: PMC7484211 DOI: 10.3389/fendo.2020.00567] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/13/2020] [Indexed: 01/22/2023] Open
Abstract
Type 2 diabetes (T2D) is a metabolic disease characterized by obesity, insulin resistance, and the dysfunction of several key glucoregulatory organs. Among these organs, impaired liver function is recognized as one of the earliest contributors to impaired whole-body glucose homeostasis, with well-characterized hepatic insulin resistance resulting in elevated rates of hepatic glucose production (HGP) and fasting hyperglycemia. One portion of this review will provide an overview of how HGP is regulated during the fasted state in healthy humans and how this process becomes dysregulated in patients with T2D. Less well-appreciated is the liver's role in post-prandial glucose metabolism, where it takes up and metabolizes one-third of orally ingested glucose. An abundance of literature has shown that the process of hepatic glucose uptake is impaired in patients with T2D, thereby contributing to glucose intolerance. A second portion of this review will outline how hepatic glucose uptake is regulated during the post-prandial state, and how it becomes dysfunctional in patients with T2D. Finally, it is well-known that exercise training has an insulin-sensitizing effect on the liver, which contributes to improved whole-body glucose metabolism in patients with T2D, thereby making it a cornerstone in the management of the disease. To this end, the impact of exercise on hepatic glucose metabolism will be thoroughly discussed, referencing key findings in the literature. At the same time, sources of heterogeneity that contribute to inconsistent findings in the field will be pointed out, as will important topics for future investigation.
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Affiliation(s)
- Shana O. Warner
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Michael V. Yao
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Rebecca L. Cason
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Jason J. Winnick
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- *Correspondence: Jason J. Winnick
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Gregory JM, Muldowney JA, Engelhardt BG, Tyree R, Marks-Shulman P, Silver HJ, Donahue EP, Edgerton DS, Winnick JJ. Aerobic exercise training improves hepatic and muscle insulin sensitivity, but reduces splanchnic glucose uptake in obese humans with type 2 diabetes. Nutr Diabetes 2019; 9:25. [PMID: 31474750 PMCID: PMC6717736 DOI: 10.1038/s41387-019-0090-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 07/30/2019] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Aerobic exercise training is known to have beneficial effects on whole-body glucose metabolism in people with type 2 diabetes (T2D). The responses of the liver to such training are less well understood. The purpose of this study was to determine the effect of aerobic exercise training on splanchnic glucose uptake (SGU) and insulin-mediated suppression of endogenous glucose production (EGP) in obese subjects with T2D. METHODS Participants included 11 obese humans with T2D, who underwent 15 ± 2 weeks of aerobic exercise training (AEX; n = 6) or remained sedentary for 15 ± 1 weeks (SED; n = 5). After an initial screening visit, each subject underwent an oral glucose load clamp and an isoglycemic/two-step (20 and 40 mU/m2/min) hyperinsulinemic clamp (ISO-clamp) to assess SGU and insulin-mediated suppression of EGP, respectively. After the intervention period, both tests were repeated. RESULTS In AEX, the ability of insulin to suppress EGP was improved during both the low (69 ± 9 and 80 ± 6% suppression; pre-post, respectively; p < 0.05) and high (67 ± 6 and 82 ± 4% suppression, respectively; p < 0.05) insulin infusion periods. Despite markedly improved muscle insulin sensitivity, SGU was reduced in AEX after training (22.9 ± 3.3 and 9.1 ± 6.0 g pre-post in AEX, respectively; p < 0.05). CONCLUSIONS In obese T2D subjects, exercise training improves whole-body glucose metabolism, in part, by improving insulin-mediated suppression of EGP and enhancing muscle glucose uptake, which occur despite reduced SGU during an oral glucose challenge.
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Affiliation(s)
- Justin M Gregory
- Ian M. Burr Division of Pediatric Endocrinology and Diabetes, Vanderbilt University School of Medicine, 1500 21st Ave, Suite 1514, Nashville, TN, 37212, USA
| | - James A Muldowney
- Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, 2215 Garland Avenue, Nashville, TN, 37232-6015, USA
| | - Brian G Engelhardt
- Division of Hematology and Oncology, Vanderbilt University School of Medicine, 2215 Garland Avenue, Nashville, TN, 37232-6015, USA
| | - Regina Tyree
- Center for Human Nutrition, Vanderbilt University School of Medicine, 2215 Garland Avenue, Nashville, TN, 37232-6015, USA
| | - Pam Marks-Shulman
- Section of Surgical Sciences, Vanderbilt University School of Medicine, 2215 Garland Avenue, Nashville, TN, 37232-6015, USA
| | - Heidi J Silver
- Center for Human Nutrition, Vanderbilt University School of Medicine, 2215 Garland Avenue, Nashville, TN, 37232-6015, USA
| | - E Patrick Donahue
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 2215 Garland Avenue, Nashville, TN, 37232-6015, USA
| | - Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 2215 Garland Avenue, Nashville, TN, 37232-6015, USA
| | - Jason J Winnick
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0547, USA.
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Kraft G, Vrba A, Scott M, Allen E, Edgerton DS, Williams PE, Vafai SB, Azamian BR, Cherrington AD. Sympathetic Denervation of the Common Hepatic Artery Lessens Glucose Intolerance in the Fat- and Fructose-Fed Dog. Diabetes 2019; 68:1143-1155. [PMID: 30936143 PMCID: PMC6610023 DOI: 10.2337/db18-1209] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 03/17/2019] [Indexed: 12/20/2022]
Abstract
This study assessed the effectiveness of surgical sympathetic denervation of the common hepatic artery (CHADN) in improving glucose tolerance. CHADN eliminated norepinephrine content in the liver and partially decreased it in the pancreas and the upper gut. We assessed oral glucose tolerance at baseline and after 4 weeks of high-fat high-fructose (HFHF) feeding. Dogs were then randomized to sham surgery (SHAM) (n = 9) or CHADN surgery (n = 11) and retested 2.5 or 3.5 weeks later while still on the HFHF diet. CHADN improved glucose tolerance by ∼60% in part because of enhanced insulin secretion, as indicated by an increase in the insulinogenic index. In a subset of dogs (SHAM, n = 5; CHADN, n = 6), a hyperinsulinemic-hyperglycemic clamp was used to assess whether CHADN could improve hepatic glucose metabolism independent of a change in insulin release. CHADN reduced the diet-induced defect in net hepatic glucose balance by 37%. In another subset of dogs (SHAM, n = 4; CHADN, n = 5) the HFHF diet was continued for 3 months postsurgery and the improvement in glucose tolerance caused by CHADN continued. In conclusion, CHADN has the potential to enhance postprandial glucose clearance in states of diet-induced glucose intolerance.
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Affiliation(s)
- Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | | | - Melanie Scott
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Eric Allen
- Hormone Assay and Analytical Services Core, Vanderbilt University Medical Center, Nashville, TN
| | - Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Hormone Assay and Analytical Services Core, Vanderbilt University Medical Center, Nashville, TN
| | - Phil E Williams
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN
| | | | | | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
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Moore MC, Smith MS, Farmer B, Coate KC, Kraft G, Shiota M, Williams PE, Cherrington AD. Morning Hyperinsulinemia Primes the Liver for Glucose Uptake and Glycogen Storage Later in the Day. Diabetes 2018; 67:1237-1245. [PMID: 29666062 PMCID: PMC6014555 DOI: 10.2337/db17-0979] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 04/10/2018] [Indexed: 12/13/2022]
Abstract
We observed that a 4-h morning (AM) duodenal infusion of glucose versus saline doubled hepatic glucose uptake (HGU) and storage during a hyperinsulinemic-hyperglycemic (HIHG) clamp that afternoon (PM). To separate the effects of AM hyperglycemia versus AM hyperinsulinemia on the PM response, we used hepatic balance and tracer ([3-3H]glucose) techniques in conscious dogs. From 0 to 240 min, dogs underwent a euinsulinemic-hyperglycemic (GLC; n = 7) or hyperinsulinemic-euglycemic (INS; n = 8) clamp. Tracer equilibration and basal sampling occurred from 240 to 360 min, followed by an HIHG clamp (360-600 min; four times basal insulin, two times basal glycemia) with portal glucose infusion (4 mg ⋅ kg-1 ⋅ min-1). In the HIHG clamp, HGU (5.8 ± 0.9 vs. 3.3 ± 0.3 mg ⋅ kg-1 ⋅ min-1) and net glycogen storage (6.0 ± 0.8 vs. 2.9 ± 0.5 mg ⋅ kg-1 ⋅ min-1) were approximately twofold greater in INS than in GLC. PM hepatic glycogen content (1.9 ± 0.2 vs. 1.3 ± 0.2 g/kg body weight) and glycogen synthase (GS) activity were also greater in INS versus GLC, whereas glycogen phosphorylase (GP) activity was reduced. Thus AM hyperinsulinemia, but not AM hyperglycemia, enhanced the HGU response to a PM HIHG clamp by augmenting GS and reducing GP activity. AM hyperinsulinemia can prime the liver to extract and store glucose more effectively during subsequent same-day meals, potentially providing a tool to improve glucose control.
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Affiliation(s)
- Mary Courtney Moore
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Marta S Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Katie C Coate
- Department of Nutrition and Dietetics, Samford University, Birmingham, AL
| | - Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Masakazu Shiota
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Phillip E Williams
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN
| | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
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Abstract
SIGNIFICANCE Among many endogenous mediators, the gasotransmitter hydrogen sulfide (H2S) plays an important role in the regulation of glucose homeostasis. In this article we discuss different functional roles of H2S in several metabolic organs/tissues required in the maintenance of glucose homeostasis. Recent Advances: New evidence has emerged revealing the insulin sensitizing role of H2S in adipose tissue and skeletal muscle biology. In addition, H2S was demonstrated to be a potent stimulator of gluconeogenesis via the induction and stimulation of various glucose-producing pathways in the liver. CRITICAL ISSUES Similar to its other physiological effects, H2S exhibits paradoxical characteristics in the regulation of glucose homeostasis: (1) H2S stimulates glucose production via activation of gluconeogenesis and glycogenolysis in hepatocytes, yet inhibits lipolysis in adipocytes; (2) H2S stimulates glucose uptake into adipocytes and skeletal muscle but inhibits glucose uptake into hepatocytes; (3) H2S inhibits insulin secretion from pancreatic β cells, yet sensitizes insulin signaling and insulin-triggered response in adipose tissues and skeletal muscle. It is also unclear the impact H2S may have on glucose metabolism and utilization by other vital organs, such as the brain. FUTURE DIRECTIONS Recent reports and ongoing studies lay the foundation for a general, although highly incomplete, understanding of the effect of H2S on regulating glucose homeostasis. In this review, we describe the molecular mechanisms and physiological outcomes of the gasotransmitter H2S on organs and tissues required for homeostatic maintenance of blood glucose. Future directions highlighting the H2S-mediated homeostatic control of glucose metabolism under physiological and insulin-resistant conditions are also discussed. Antioxid. Redox Signal. 28, 1463-1482.
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Affiliation(s)
- Ashley Untereiner
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| | - Lingyun Wu
- 2 Cardiovascular & Metabolic Research Unit and School of Human Kinetics, Laurentian University , Sudbury, Canada .,3 Health Sciences North Research Institute , Sudbury, Canada
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Moore MC, Smith MS, Farmer B, Kraft G, Shiota M, Williams PE, Cherrington AD. Priming Effect of a Morning Meal on Hepatic Glucose Disposition Later in the Day. Diabetes 2017; 66:1136-1145. [PMID: 28174290 PMCID: PMC5399607 DOI: 10.2337/db16-1308] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 01/28/2017] [Indexed: 01/15/2023]
Abstract
We used hepatic balance and tracer ([3H]glucose) techniques to examine the impact of "breakfast" on hepatic glucose metabolism later in the same day. From 0-240 min, 2 groups of conscious dogs (n = 9 dogs/group) received a duodenal infusion of glucose (GLC) or saline (SAL), then were fasted from 240-360 min. Three dogs from each group were euthanized and tissue collected at 360 min. From 360-600 min, the remaining dogs underwent a hyperinsulinemic (4× basal) hyperglycemic clamp (arterial blood glucose 146 ± 2 mg/dL) with portal GLC infusion. The total GLC infusion rate was 14% greater in dogs infused with GLC than in those receiving SAL (AUC360-600min 2,979 ± 296 vs. 2,597 ± 277 mg/kg, respectively). The rates of hepatic glucose uptake (5.8 ± 0.8 vs. 3.2 ± 0.3 mg ⋅ kg-1 ⋅ min-1) and glycogen storage (4.7 ± 0.6 vs. 2.9 ± 0.3 mg ⋅ kg-1 ⋅ min-1) during the clamp were markedly greater in dogs receiving GLC compared with those receiving SAL. Hepatic glycogen content was ∼50% greater, glycogen synthase activity was ∼50% greater, glycogen phosphorylase activity was ∼50% lower, and the amount of phosphorylated glycogen synthase was 34% lower, indicating activation of the enzyme, in dogs receiving GLC compared with those receiving SAL. Thus, morning GLC primed the liver to extract and store more glucose in the presence of hyperinsulinemic hyperglycemia later in the same day, indicating that breakfast enhances the liver's role in glucose disposal in subsequent same-day meals.
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Affiliation(s)
- Mary Courtney Moore
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Marta S Smith
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Ben Farmer
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Guillaume Kraft
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Masakazu Shiota
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Phillip E Williams
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN
| | - Alan D Cherrington
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
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Winnick JJ, Kraft G, Gregory JM, Edgerton DS, Williams P, Hajizadeh IA, Kamal MZ, Smith M, Farmer B, Scott M, Neal D, Donahue EP, Allen E, Cherrington AD. Hepatic glycogen can regulate hypoglycemic counterregulation via a liver-brain axis. J Clin Invest 2016; 126:2236-48. [PMID: 27140398 DOI: 10.1172/jci79895] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 03/10/2016] [Indexed: 11/17/2022] Open
Abstract
Liver glycogen is important for the counterregulation of hypoglycemia and is reduced in individuals with type 1 diabetes (T1D). Here, we examined the effect of varying hepatic glycogen content on the counterregulatory response to low blood sugar in dogs. During the first 4 hours of each study, hepatic glycogen was increased by augmenting hepatic glucose uptake using hyperglycemia and a low-dose intraportal fructose infusion. After hepatic glycogen levels were increased, animals underwent a 2-hour control period with no fructose infusion followed by a 2-hour hyperinsulinemic/hypoglycemic clamp. Compared with control treatment, fructose infusion caused a large increase in liver glycogen that markedly elevated the response of epinephrine and glucagon to a given hypoglycemia and increased net hepatic glucose output (NHGO). Moreover, prior denervation of the liver abolished the improved counterregulatory responses that resulted from increased liver glycogen content. When hepatic glycogen content was lowered, glucagon and NHGO responses to insulin-induced hypoglycemia were reduced. We conclude that there is a liver-brain counterregulatory axis that is responsive to liver glycogen content. It remains to be determined whether the risk of iatrogenic hypoglycemia in T1D humans could be lessened by targeting metabolic pathway(s) associated with hepatic glycogen repletion.
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Hempel M, Schmitz A, Winkler S, Kucukoglu O, Brückner S, Niessen C, Christ B. Pathological implications of cadherin zonation in mouse liver. Cell Mol Life Sci 2015; 72:2599-612. [PMID: 25687506 PMCID: PMC11113307 DOI: 10.1007/s00018-015-1861-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 02/10/2015] [Accepted: 02/11/2015] [Indexed: 02/07/2023]
Abstract
Both acute and chronic liver diseases are associated with ample re-modeling of the liver parenchyma leading to functional impairment, which is thus obviously the cause or the consequence of the disruption of the epithelial integrity. It was, therefore, the aim of this study to investigate the distribution of the adherens junction components E- and N-cadherin, which are important determinants of tissue cohesion. E-cadherin was expressed in periportal but not in perivenous hepatocytes. In contrast, N-cadherin was more enriched towards the perivenous hepatocytes. In agreement, β-catenin, which links both cadherins via α-catenin to the actin cytoskeleton, was expressed ubiquitously. This zonal expression of cadherins was preserved in acute liver injury after treatment with acetaminophen or partial hepatectomy, but disrupted in chronic liver damage like in non-alcoholic steatohepatitis (NASH) or α1-antitrypsin deficiency. Hepatocyte proliferation during acetaminophen-induced liver damage was predominant at the boundary between the damaged perivenous and the intact periportal parenchyma indicating a minor contribution of periportal hepatocytes to liver regeneration. In NASH livers, an oval cell reaction was observed pointing to massive tissue damage coinciding with the gross impairment of hepatocyte proliferation. In the liver parenchyma, metabolic functions are distributed heterogeneously. For example, the expression of phosphoenolpyruvate carboxykinase and E-cadherin overlapped in periportal hepatocytes. Thus, during liver regeneration after acute damage, the intact periportal parenchyma might sustain essential metabolic support like glucose supply or ammonia detoxification. However, disruption of epithelial integrity during chronic challenges may increase susceptibility to metabolic liver diseases such as NASH or vice versa. This might suggest the regulatory integration of tissue cohesion and metabolic functions in the liver.
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Affiliation(s)
- Madlen Hempel
- Applied Molecular Hepatology Lab, Department of Visceral, Transplantation, Thoracic and Vascular Surgery, University of Leipzig, Liebigstraße 21, 04103 Leipzig, Germany
| | - Annika Schmitz
- Department of Dermatology, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Sandra Winkler
- Applied Molecular Hepatology Lab, Department of Visceral, Transplantation, Thoracic and Vascular Surgery, University of Leipzig, Liebigstraße 21, 04103 Leipzig, Germany
| | - Ozlem Kucukoglu
- Applied Molecular Hepatology Lab, Department of Visceral, Transplantation, Thoracic and Vascular Surgery, University of Leipzig, Liebigstraße 21, 04103 Leipzig, Germany
- Translational Centre for Regenerative Medicine (TRM), Universität Leipzig, Leipzig, Germany
| | - Sandra Brückner
- Applied Molecular Hepatology Lab, Department of Visceral, Transplantation, Thoracic and Vascular Surgery, University of Leipzig, Liebigstraße 21, 04103 Leipzig, Germany
| | - Carien Niessen
- Department of Dermatology, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Bruno Christ
- Applied Molecular Hepatology Lab, Department of Visceral, Transplantation, Thoracic and Vascular Surgery, University of Leipzig, Liebigstraße 21, 04103 Leipzig, Germany
- Translational Centre for Regenerative Medicine (TRM), Universität Leipzig, Leipzig, Germany
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Chen SS, Otero YF, Mulligan KX, Lundblad TM, Williams PE, McGuinness OP. Liver, but not muscle, has an entrainable metabolic memory. PLoS One 2014; 9:e86164. [PMID: 24465939 PMCID: PMC3900485 DOI: 10.1371/journal.pone.0086164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 12/06/2013] [Indexed: 02/05/2023] Open
Abstract
Hyperglycemia in the hospitalized setting is common, especially in patients that receive nutritional support either continuously or intermittently. As the liver and muscle are the major sites of glucose disposal, we hypothesized their metabolic adaptations are sensitive to the pattern of nutrient delivery. Chronically catheterized, well-controlled depancreatized dogs were placed on one of three isocaloric diets: regular chow diet once daily (Chow) or a simple nutrient diet (ND) that was given either once daily (ND-4) or infused continuously (ND-C). Intraportal insulin was infused to maintain euglycemia. After 5 days net hepatic (NHGU) and muscle (MGU) glucose uptake and oxidation were assessed at euglycemia (120 mg/dl) and hyperglycemia (200 mg/dl) in the presence of basal insulin. While hyperglycemia increased both NHGU and MGU in Chow, NHGU was amplified in both groups receiving ND. The increase was associated with enhanced activation of glycogen synthase, glucose oxidation and suppression of pyruvate dehydrogenase kinase-4 (PDK-4). Accelerated glucose-dependent muscle glucose uptake was only evident with ND-C. This was associated with a decrease in PDK-4 expression and an increase in AMP-activated protein kinase (AMPK) phosphorylation. Interestingly, ND-C markedly increased hepatic FGF-21 expression. Thus, augmentation of carbohydrate disposal in the liver, as opposed to the muscle, is not dependent on the pattern of nutrient delivery.
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Affiliation(s)
- Sheng-Song Chen
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Yolanda F. Otero
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Kimberly X. Mulligan
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Tammy M. Lundblad
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Phillip E. Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Owen P. McGuinness
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail:
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Winnick JJ, An Z, Kraft G, Ramnanan CJ, Irimia JM, Smith M, Lautz M, Roach PJ, Cherrington AD. Liver glycogen loading dampens glycogen synthesis seen in response to either hyperinsulinemia or intraportal glucose infusion. Diabetes 2013; 62:96-101. [PMID: 22923473 PMCID: PMC3526057 DOI: 10.2337/db11-1773] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The purpose of this study was to determine the effect of liver glycogen loading on net hepatic glycogen synthesis during hyperinsulinemia or hepatic portal vein glucose infusion in vivo. Liver glycogen levels were supercompensated (SCGly) in two groups (using intraportal fructose infusion) but not in two others (Gly) during hyperglycemic-normoinsulinemia. Following a 2-h control period during which fructose infusion was stopped, there was a 2-h experimental period in which the response to hyperglycemia plus either 4× basal insulin (INS) or portal vein glucose infusion (PoG) was measured. Increased hepatic glycogen reduced the percent of glucose taken up by the liver that was deposited in glycogen (74 ± 3 vs. 53 ± 5% in Gly+INS and SCGly+INS, respectively, and 72 ± 3 vs. 50 ± 6% in Gly+PoG and SCGly+PoG, respectively). The reduction in liver glycogen synthesis in SCGly+INS was accompanied by a decrease in both insulin signaling and an increase in AMPK activation, whereas only the latter was observed in SCGly+PoG. These data indicate that liver glycogen loading impairs glycogen synthesis regardless of the signal used to stimulate it.
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Affiliation(s)
- Jason J Winnick
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
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15
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Soares AF, Carvalho RA, Veiga FJ, Alves MG, Martins FO, Viegas I, González JD, Metón I, Baanante IV, Jones JG. Restoration of direct pathway glycogen synthesis flux in the STZ-diabetes rat model by insulin administration. Am J Physiol Endocrinol Metab 2012; 303:E875-85. [PMID: 22850684 DOI: 10.1152/ajpendo.00161.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Type 1 diabetes subjects are characterized by impaired direct pathway synthesis of hepatic glycogen that is unresponsive to insulin therapy. Since it is not known whether this is an irreversible defect of insulin-dependent diabetes, direct and indirect pathway glycogen fluxes were quantified in streptozotocin (STZ)-induced diabetic rats and compared with STZ rats that received subcutaneous or intraperitoneal insulin (I-SC or I-IP). Three groups of STZ rats were studied at 18 days post-STZ treatment. One group was administered I-SC and another I-IP as two daily injections of short-acting insulin at the start of each light and dark period for days 9-18. A third group did not receive any insulin, and a fourth group of nondiabetic rats was used as control. Glycogen synthesis via direct and indirect pathways, de novo lipogenesis, and gluconeogenesis were determined over the nocturnal feeding period using deuterated water. Direct pathway was residual in STZ rats, and glucokinase activity was also reduced significantly from control levels. Insulin administration restored both net glycogen synthesis via the direct pathway and glucokinase activity to nondiabetic control levels and improved the lipogenic pathway despite an inefficient normalization of the gluconeogenic pathway. We conclude that the reduced direct pathway flux is not an irreversible defect of insulin-dependent diabetes.
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Affiliation(s)
- Ana F Soares
- Center for Neuroscience and Cell Biology, Dept. of Life Sciences, Univ. of Coimbra, Largo Marquês de Pombal, 3004 - 517, Coimbra, Portugal
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16
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An Z, Winnick JJ, Moore MC, Farmer B, Smith M, Irimia JM, Roach PJ, Cherrington AD. A cyclic guanosine monophosphate-dependent pathway can regulate net hepatic glucose uptake in vivo. Diabetes 2012; 61:2433-41. [PMID: 22688328 PMCID: PMC3447895 DOI: 10.2337/db11-1816] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We previously showed that hepatic nitric oxide regulates net hepatic glucose uptake (NHGU), an effect that can be eliminated by inhibiting hepatic soluble guanylate cyclase (sGC), suggesting that the sGC pathway is involved in the regulation of NHGU. The aim of the current study was to determine whether hepatic cyclic guanosine monophosphate (cGMP) reduces NHGU. Studies were performed on conscious dogs with transhepatic catheters. A hyperglycemic-hyperinsulinemic clamp was established in the presence of portal vein glucose infusion. 8-Br-cGMP (50 µg/kg/min) was delivered intraportally, and either the glucose load to the liver (CGMP/GLC; n = 5) or the glucose concentration entering the liver (CGMP/GCC; n = 5) was clamped at 2× basal. In the control group, saline was given intraportally (SAL; n = 10), and the hepatic glucose concentration and load were doubled. 8-Br-cGMP increased portal blood flow, necessitating the two approaches to glucose clamping in the cGMP groups. NHGU (mg/kg/min) was 5.8 ± 0.5, 2.7 ± 0.5, and 4.8 ± 0.3, whereas the fractional extraction of glucose was 11.0 ± 1, 5.5 ± 1, and 8.5 ± 1% during the last hour of the study in SAL, CGMP/GLC, and CGMP/GCC, respectively. The reduction of NHGU in response to 8-Br-cGMP was associated with increased AMP-activated protein kinase phosphorylation. These data indicate that changes in liver cGMP can regulate NHGU under postprandial conditions.
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Affiliation(s)
- Zhibo An
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
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17
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Moore MC, Coate KC, Winnick JJ, An Z, Cherrington AD. Regulation of hepatic glucose uptake and storage in vivo. Adv Nutr 2012; 3:286-94. [PMID: 22585902 PMCID: PMC3649460 DOI: 10.3945/an.112.002089] [Citation(s) in RCA: 229] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
In the postprandial state, the liver takes up and stores glucose to minimize the fluctuation of glycemia. Elevated insulin concentrations, an increase in the load of glucose reaching the liver, and the oral/enteral/portal vein route of glucose delivery (compared with the peripheral intravenous route) are factors that increase the rate of net hepatic glucose uptake (NHGU). The entry of glucose into the portal vein stimulates a portal glucose signal that not only enhances NHGU but concomitantly reduces muscle glucose uptake to ensure appropriate partitioning of a glucose load. This coordinated regulation of glucose uptake is likely neurally mediated, at least in part, because it is not observed after total hepatic denervation. Moreover, there is evidence that both the sympathetic and the nitrergic innervation of the liver exert a tonic repression of NHGU that is relieved under feeding conditions. Further, the energy sensor 5'AMP-activated protein kinase appears to be involved in regulation of NHGU and glycogen storage. Consumption of a high-fat and high-fructose diet impairs NHGU and glycogen storage in association with a reduction in glucokinase protein and activity. An understanding of the impact of nutrients themselves and the route of nutrient delivery on liver carbohydrate metabolism is fundamental to the development of therapies for impaired postprandial glucoregulation.
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Affiliation(s)
- Mary Courtney Moore
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Katie C. Coate
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN,current address: Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jason J. Winnick
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Zhibo An
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN,current address: Department of Medicine, Division of Endocrinology, University of Cincinnati Medical Center, Cincinnati, OH
| | - Alan D. Cherrington
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
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Ros S, García-Rocha M, Calbó J, Guinovart JJ. Restoration of hepatic glycogen deposition reduces hyperglycaemia, hyperphagia and gluconeogenic enzymes in a streptozotocin-induced model of diabetes in rats. Diabetologia 2011; 54:2639-48. [PMID: 21811873 DOI: 10.1007/s00125-011-2238-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 06/10/2011] [Indexed: 01/28/2023]
Abstract
AIMS/HYPOTHESIS Glycogen deposition is impaired in diabetes, thus contributing to the development of hyperglycaemia. Several glucose-lowering strategies have attempted to increase liver glycogen deposition by modulating targets, which eventually trigger the activation of liver glycogen synthase (LGS). However, these targets also alter several other biological processes, and therefore their therapeutic use may be limited. Here we tested the approach of directly activating LGS and evaluated the potential of this strategy as a possible treatment for diabetes. METHODS In this study, we examined the efficacy of directly overproducing a constitutively active form of LGS in the liver to ameliorate streptozotocin-induced diabetes in rats. RESULTS Activated mutant LGS overproduction in the liver of streptozotocin-induced diabetic rats normalised liver glycogen content, despite low levels of glucokinase and circulating insulin. Moreover, this overproduction led to a decrease in food intake and in the production of the main gluconeogenic enzymes, glucose-6-phosphatase, fructose-1,6-bisphosphatase and phosphoenolpyruvate carboxykinase. The resulting combined effect was a reduction in hyperglycaemia. CONCLUSIONS/INTERPRETATION The restoration of liver glycogen ameliorated diabetes and therefore is considered a potential strategy for the treatment of this disease.
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Affiliation(s)
- S Ros
- Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, 08028 Barcelona, Spain
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