1
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Hu L, Liu H, Ma H, Zeng X, Cao Y, Liu B, Li H, Zhang X. TRAF6-mediated ubiquitination of AKT1 in the nucleus occurs in a β-arrestin2-dependent manner upon insulin stimulation. Biochem Pharmacol 2024; 226:116362. [PMID: 38871335 DOI: 10.1016/j.bcp.2024.116362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 05/25/2024] [Accepted: 06/10/2024] [Indexed: 06/15/2024]
Abstract
AKT, also known as protein kinase B (PKB), serves as a crucial regulator of numerous biological functions, including cell growth, metabolism, and tumorigenesis. Increasing evidence suggests that the kinase activity of AKT is regulated via ubiquitination by various E3 ligase enzymes in response to different stimuli. However, the molecular mechanisms underlying insulin-induced AKT ubiquitination are not yet fully understood. Here, we show that activation of the insulin receptor (IR) leads to enhanced ubiquitination of AKT1 at K8 and K14 residues, facilitated by the cytosolic E3 ubiquitin ligase enzyme, TRAF6. Further investigation using AKT1 mutants with modified nucleocytoplasmic shuttling properties reveals that TRAF6-mediated AKT1 ubiquitination occurs within the nucleus in a β-Arr2-dependent manner. The nuclear entry of TRAF6 depends on importin β1, while β-Arr2 regulates this process by facilitating the interaction between TRAF6 and importin β1. Additionally, the ubiquitination of AKT1 is essential for its translocation to the activated IR on the plasma membrane, where it plays a functional role in recruiting Glut4 and facilitating glucose uptake. This study uncovers the cellular components and processes involved in insulin-induced ubiquitination and activation of AKT1, providing insights and detailed strategies for manipulating AKT1.
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Affiliation(s)
- Li Hu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang 550025, China
| | - Haiping Liu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang 550025, China
| | - Haixiang Ma
- School of Pharmaceutical Sciences, Guizhou University, Guiyang 550025, China
| | - Xingyue Zeng
- School of Pharmaceutical Sciences, Guizhou University, Guiyang 550025, China
| | - Yongkai Cao
- Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen 518035, China
| | - Bing Liu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang 550025, China
| | - Huijun Li
- Department of Pharmaceuticals, People's Hospital of Zunyi City Bo Zhou District, Zunyi 563000, China
| | - Xiaohan Zhang
- School of Pharmaceutical Sciences, Guizhou University, Guiyang 550025, China.
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2
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Anthofer L, Gmach P, Uretmen Kagiali ZC, Kleinau G, Rotter J, Opitz R, Scheerer P, Beck-Sickinger AG, Wolf P, Biebermann H, Bechmann I, Kühnen P, Krude H, Paisdzior S. Melanocortin-4 Receptor PLC Activation Is Modulated by an Interaction with the Monocarboxylate Transporter 8. Int J Mol Sci 2024; 25:7565. [PMID: 39062808 PMCID: PMC11277258 DOI: 10.3390/ijms25147565] [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: 06/14/2024] [Revised: 07/05/2024] [Accepted: 07/06/2024] [Indexed: 07/28/2024] Open
Abstract
The melanocortin-4 receptor (MC4R) is a key player in the hypothalamic leptin-melanocortin pathway that regulates satiety and hunger. MC4R belongs to the G protein-coupled receptors (GPCRs), which are known to form heterodimers with other membrane proteins, potentially modulating receptor function or characteristics. Like MC4R, thyroid hormones (TH) are also essential for energy homeostasis control. TH transport across membranes is facilitated by the monocarboxylate transporter 8 (MCT8), which is also known to form heterodimers with GPCRs. Based on the finding in single-cell RNA-sequencing data that both proteins are simultaneously expressed in hypothalamic neurons, we investigated a putative interplay between MC4R and MCT8. We developed a novel staining protocol utilizing a fluorophore-labeled MC4R ligand and demonstrated a co-localization of MC4R and MCT8 in human brain tissue. Using in vitro assays such as BRET, IP1, and cAMP determination, we found that MCT8 modulates MC4R-mediated phospholipase C activation but not cAMP formation via a direct interaction, an effect that does not require a functional MCT8 as it was not altered by a specific MCT8 inhibitor. This suggests an extended functional spectrum of MCT8 as a GPCR signaling modulator and argues for the investigation of further GPCR-protein interactions with hitherto underrepresented physiological functions.
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Affiliation(s)
- Larissa Anthofer
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
- Institute of Anatomy, Leipzig University, D-04103 Leipzig, Germany
| | - Philipp Gmach
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Zeynep Cansu Uretmen Kagiali
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Gunnar Kleinau
- Group Structural Biology of Cellular Signaling, Institute of Medical Physics and Biophysics, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Jonas Rotter
- Institute of Anatomy, Leipzig University, D-04103 Leipzig, Germany
| | - Robert Opitz
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Patrick Scheerer
- Group Structural Biology of Cellular Signaling, Institute of Medical Physics and Biophysics, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | | | - Philipp Wolf
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, D-04103 Leipzig, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Ingo Bechmann
- Institute of Anatomy, Leipzig University, D-04103 Leipzig, Germany
| | - Peter Kühnen
- Department for Pediatric Endocrinology and Diabetology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Heiko Krude
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Sarah Paisdzior
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
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3
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Jaykumar AB, Binns D, Taylor CA, Anselmo A, Birnbaum SG, Huber KM, Cobb MH. WNKs regulate mouse behavior and alter central nervous system glucose uptake and insulin signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.09.598125. [PMID: 38915673 PMCID: PMC11195145 DOI: 10.1101/2024.06.09.598125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Certain areas of the brain involved in episodic memory and behavior, such as the hippocampus, express high levels of insulin receptors and glucose transporter-4 (GLUT4) and are responsive to insulin. Insulin and neuronal glucose metabolism improve cognitive functions and regulate mood in humans. Insulin-dependent GLUT4 trafficking has been extensively studied in muscle and adipose tissue, but little work has demonstrated either how it is controlled in insulin-responsive brain regions or its mechanistic connection to cognitive functions. In this study, we demonstrate that inhibition of WNK (With-No-lysine (K)) kinases improves learning and memory in mice. Neuronal inhibition of WNK enhances in vivo hippocampal glucose uptake. Inhibition of WNK enhances insulin signaling output and insulin-dependent GLUT4 trafficking to the plasma membrane in mice primary neuronal cultures and hippocampal slices. Therefore, we propose that the extent of neuronal WNK kinase activity has an important influence on learning, memory and anxiety-related behaviors, in part, by modulation of neuronal insulin signaling.
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Affiliation(s)
- Ankita B. Jaykumar
- Departments of Pharmacology, UT Southwestern Medical Center, Dallas, USA
| | - Derk Binns
- Departments of Pharmacology, UT Southwestern Medical Center, Dallas, USA
| | - Clinton A. Taylor
- Departments of Pharmacology, UT Southwestern Medical Center, Dallas, USA
| | - Anthony Anselmo
- Departments of Pharmacology, UT Southwestern Medical Center, Dallas, USA
| | - Shari G. Birnbaum
- Departments of Peter O’Donnell Jr. Brain Institute and Psychiatry, UT Southwestern Medical Center, Dallas, USA
| | | | - Melanie H. Cobb
- Departments of Pharmacology, UT Southwestern Medical Center, Dallas, USA
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4
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Ham S, Mukaida S, Sato M, Keov P, Bengtsson T, Furness S, Holliday ND, Evans BA, Summers RJ, Hutchinson DS. Role of G protein-coupled receptor kinases (GRKs) in β 2 -adrenoceptor-mediated glucose uptake. Pharmacol Res Perspect 2024; 12:e1176. [PMID: 38332691 PMCID: PMC10853676 DOI: 10.1002/prp2.1176] [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: 09/12/2023] [Revised: 12/17/2023] [Accepted: 01/22/2024] [Indexed: 02/10/2024] Open
Abstract
Truncation of the C-terminal tail of the β2 -AR, transfection of βARKct or over-expression of a kinase-dead GRK mutant reduces isoprenaline-stimulated glucose uptake, indicating that GRK is important for this response. We explored whether phosphorylation of the β2 -AR by GRK2 has a role in glucose uptake or if this response is related to the role of GRK2 as a scaffolding protein. CHO-GLUT4myc cells expressing wild-type and mutant β2 -ARs were generated and receptor affinity for [3 H]-CGP12177A and density of binding sites determined together with the affinity of isoprenaline and BRL37344. Following receptor activation by β2 -AR agonists, cAMP accumulation, GLUT4 translocation, [3 H]-2-deoxyglucose uptake, and β2 -AR internalization were measured. Bioluminescence resonance energy transfer was used to investigate interactions between β2 -AR and β-arrestin2 or between β2 -AR and GRK2. Glucose uptake after siRNA knockdown or GRK inhibitors was measured in response to β2 -AR agonists. BRL37344 was a poor partial agonist for cAMP generation but displayed similar potency and efficacy to isoprenaline for glucose uptake and GLUT4 translocation. These responses to β2 -AR agonists occurred in CHO-GLUT4myc cells expressing β2 -ARs lacking GRK or GRK/PKA phosphorylation sites as well as in cells expressing the wild-type β2 -AR. However, β2 -ARs lacking phosphorylation sites failed to recruit β-arrestin2 and did not internalize. GRK2 knock-down or GRK2 inhibitors decreased isoprenaline-stimulated glucose uptake in rat L6 skeletal muscle cells. Thus, GRK phosphorylation of the β2 -AR is not associated with isoprenaline- or BRL37344-stimulated glucose uptake. However, GRKs acting as scaffold proteins are important for glucose uptake as GRK2 knock-down or GRK2 inhibition reduces isoprenaline-stimulated glucose uptake.
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Affiliation(s)
- Seungmin Ham
- Drug Discovery BiologyMonash Institute of Pharmaceutical Sciences, Monash UniversityParkvilleVictoriaAustralia
| | - Saori Mukaida
- Drug Discovery BiologyMonash Institute of Pharmaceutical Sciences, Monash UniversityParkvilleVictoriaAustralia
| | - Masaaki Sato
- Drug Discovery BiologyMonash Institute of Pharmaceutical Sciences, Monash UniversityParkvilleVictoriaAustralia
| | - Peter Keov
- Drug Discovery BiologyMonash Institute of Pharmaceutical Sciences, Monash UniversityParkvilleVictoriaAustralia
| | - Tore Bengtsson
- Atrogi ABStockholmSweden
- Department of Molecular BiosciencesThe Wenner‐Gren Institute, Stockholm UniversityStockholmSweden
| | - Sebastian Furness
- Drug Discovery BiologyMonash Institute of Pharmaceutical Sciences, Monash UniversityParkvilleVictoriaAustralia
| | - Nicholas D. Holliday
- School of Life Sciences, The Medical School, Queen's Medical CentreUniversity of NottinghamNottinghamUK
- Excellerate Bioscience, BiocityNottinghamUK
| | - Bronwyn A. Evans
- Drug Discovery BiologyMonash Institute of Pharmaceutical Sciences, Monash UniversityParkvilleVictoriaAustralia
| | - Roger J. Summers
- Drug Discovery BiologyMonash Institute of Pharmaceutical Sciences, Monash UniversityParkvilleVictoriaAustralia
| | - Dana S. Hutchinson
- Drug Discovery BiologyMonash Institute of Pharmaceutical Sciences, Monash UniversityParkvilleVictoriaAustralia
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5
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Matt RA, Martin RS, Evans AK, Gever JR, Vargas GA, Shamloo M, Ford AP. Locus Coeruleus and Noradrenergic Pharmacology in Neurodegenerative Disease. Handb Exp Pharmacol 2024; 285:555-616. [PMID: 37495851 DOI: 10.1007/164_2023_677] [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: 07/28/2023]
Abstract
Adrenoceptors (ARs) throughout the brain are stimulated by noradrenaline originating mostly from neurons of the locus coeruleus, a brainstem nucleus that is ostensibly the earliest to show detectable pathology in neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. The α1-AR, α2-AR, and β-AR subtypes expressed in target brain regions and on a range of cell populations define the physiological responses to noradrenaline, which includes activation of cognitive function in addition to modulation of neurometabolism, cerebral blood flow, and neuroinflammation. As these heterocellular functions are critical for maintaining brain homeostasis and neuronal health, combating the loss of noradrenergic tone from locus coeruleus degeneration may therefore be an effective treatment for both cognitive symptoms and disease modification in neurodegenerative indications. Two pharmacologic approaches are receiving attention in recent clinical studies: preserving noradrenaline levels (e.g., via reuptake inhibition) and direct activation of target adrenoceptors. Here, we review the expression and role of adrenoceptors in the brain, the preclinical studies which demonstrate that adrenergic stimulation can support cognitive function and cerebral health by reversing the effects of noradrenaline depletion, and the human data provided by pharmacoepidemiologic analyses and clinical trials which together identify adrenoceptors as promising targets for the treatment of neurodegenerative disease.
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Affiliation(s)
| | | | - Andrew K Evans
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA, USA
| | | | | | - Mehrdad Shamloo
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA, USA
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6
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Paulussen F, Kulkarni CP, Stolz F, Lescrinier E, De Graeve S, Lambin S, Marchand A, Chaltin P, In't Veld P, Mebis J, Tavernier J, Van Dijck P, Luyten W, Thevelein JM. The β2-adrenergic receptor in the apical membrane of intestinal enterocytes senses sugars to stimulate glucose uptake from the gut. Front Cell Dev Biol 2023; 10:1041930. [PMID: 36699012 PMCID: PMC9869975 DOI: 10.3389/fcell.2022.1041930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 12/14/2022] [Indexed: 01/12/2023] Open
Abstract
The presence of sugar in the gut causes induction of SGLT1, the sodium/glucose cotransporter in intestinal epithelial cells (enterocytes), and this is accompanied by stimulation of sugar absorption. Sugar sensing was suggested to involve a G-protein coupled receptor and cAMP - protein kinase A signalling, but the sugar receptor has remained unknown. We show strong expression and co-localization with SGLT1 of the β2-adrenergic receptor (β 2-AR) at the enterocyte apical membrane and reveal its role in stimulating glucose uptake from the gut by the sodium/glucose-linked transporter, SGLT1. Upon heterologous expression in different reporter systems, the β 2-AR responds to multiple sugars in the mM range, consistent with estimated gut sugar levels after a meal. Most adrenergic receptor antagonists inhibit sugar signaling, while some differentially inhibit epinephrine and sugar responses. However, sugars did not inhibit binding of I125-cyanopindolol, a β 2-AR antagonist, to the ligand-binding site in cell-free membrane preparations. This suggests different but interdependent binding sites. Glucose uptake into everted sacs from rat intestine was stimulated by epinephrine and sugars in a β 2-AR-dependent manner. STD-NMR confirmed direct physical binding of glucose to the β 2-AR. Oral administration of glucose with a non-bioavailable β 2-AR antagonist lowered the subsequent increase in blood glucose levels, confirming a role for enterocyte apical β 2-ARs in stimulating gut glucose uptake, and suggesting enterocyte β 2-AR as novel drug target in diabetic and obese patients. Future work will have to reveal how glucose sensing by enterocytes and neuroendocrine cells is connected, and whether β 2-ARs mediate glucose sensing also in other tissues.
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Affiliation(s)
- Frederik Paulussen
- 1Center for Microbiology, VIB, Leuven-Heverlee, Belgium,2Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
| | - Chetan P. Kulkarni
- 1Center for Microbiology, VIB, Leuven-Heverlee, Belgium,3Functional Genomics and Proteomics Research Unit, Department of Biology, KU Leuven, Leuven, Belgium
| | - Frank Stolz
- 1Center for Microbiology, VIB, Leuven-Heverlee, Belgium,2Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
| | - Eveline Lescrinier
- 4Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Stijn De Graeve
- 1Center for Microbiology, VIB, Leuven-Heverlee, Belgium,2Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
| | - Suzan Lambin
- 1Center for Microbiology, VIB, Leuven-Heverlee, Belgium,2Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
| | | | | | - Peter In't Veld
- 6Department of Pathology, Free University of Brussels, Brussels, Belgium
| | - Joseph Mebis
- 7Department of Pathology, KU Leuven, Flanders, Belgium
| | - Jan Tavernier
- 8Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium,9Center for Medical Biotechnology, VIB, Ghent, Belgium
| | - Patrick Van Dijck
- 1Center for Microbiology, VIB, Leuven-Heverlee, Belgium,2Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
| | - Walter Luyten
- 3Functional Genomics and Proteomics Research Unit, Department of Biology, KU Leuven, Leuven, Belgium
| | - Johan M. Thevelein
- 1Center for Microbiology, VIB, Leuven-Heverlee, Belgium,2Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium,10NovelYeast bv, Bio-Incubator BIO4, Gaston Geenslaan 3, Leuven-Heverlee,, Belgium,*Correspondence: Johan M. Thevelein,
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7
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Gao Z, Min X, Kim KM, Liu H, Hu L, Wu C, Zhang X. The tyrosine phosphorylation of GRK2 is responsible for activated D2R-mediated insulin resistance. Biochem Biophys Res Commun 2022; 628:40-48. [DOI: 10.1016/j.bbrc.2022.08.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 08/16/2022] [Accepted: 08/19/2022] [Indexed: 11/02/2022]
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8
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Murray J, Ehsani A, Najjar L, Zhang G, Itakura K. Muscle-specific deletion of Arid5b causes metabolic changes in skeletal muscle that affect adipose tissue and liver. Front Endocrinol (Lausanne) 2022; 13:1083311. [PMID: 36743919 PMCID: PMC9891308 DOI: 10.3389/fendo.2022.1083311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 12/30/2022] [Indexed: 01/20/2023] Open
Abstract
Emerging evidence suggests that AT-Rich Interaction Domain 5b (Arid5b) may play a role in energy metabolism in various tissues. To study the metabolic function of Arid5b in skeletal muscle, we generated skeletal muscle-specific Arid5b knockout (Arid5b MKO) mice. We found that Arid5b MKO skeletal muscles preferentially utilized fatty acids for energy generation with a corresponding increase in FABP4 expression. Interestingly, in Arid5b MKO mice, the adipose tissue weight decreased significantly. One possible mechanism for the decrease in adipose tissue weight could be the increase in phospho-HSL and HSL expression in white adipose tissue. While glucose uptake increased in an insulin-independent manner in Arid5b MKO skeletal muscle, glucose oxidation was reduced in conjunction with downregulation of the mitochondrial pyruvate carrier (MPC). We found that glucose was diverted into the pentose phosphate pathway as well as converted into lactate through glycolysis for export to the bloodstream, fueling the Cori cycle. Our data show that muscle-specific deletion of Arid5b leads to changes in fuel utilization in skeletal muscle that influences metabolism in other tissues. These results suggest that Arid5b regulates systemic metabolism by modulating fuel selection.
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9
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Kolodziej F, O’Halloran KD. Re-Evaluating the Oxidative Phenotype: Can Endurance Exercise Save the Western World? Antioxidants (Basel) 2021; 10:609. [PMID: 33921022 PMCID: PMC8071436 DOI: 10.3390/antiox10040609] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/06/2021] [Accepted: 04/10/2021] [Indexed: 01/16/2023] Open
Abstract
Mitochondria are popularly called the "powerhouses" of the cell. They promote energy metabolism through the tricarboxylic acid (TCA) cycle and oxidative phosphorylation, which in contrast to cytosolic glycolysis are oxygen-dependent and significantly more substrate efficient. That is, mitochondrial metabolism provides substantially more cellular energy currency (ATP) per macronutrient metabolised. Enhancement of mitochondrial density and metabolism are associated with endurance training, which allows for the attainment of high relative VO2 max values. However, the sedentary lifestyle and diet currently predominant in the Western world lead to mitochondrial dysfunction. Underdeveloped mitochondrial metabolism leads to nutrient-induced reducing pressure caused by energy surplus, as reduced nicotinamide adenine dinucleotide (NADH)-mediated high electron flow at rest leads to "electron leak" and a chronic generation of superoxide radicals (O2-). Chronic overload of these reactive oxygen species (ROS) damages cell components such as DNA, cell membranes, and proteins. Counterintuitively, transiently generated ROS during exercise contributes to adaptive reduction-oxidation (REDOX) signalling through the process of cellular hormesis or "oxidative eustress" defined by Helmut Sies. However, the unaccustomed, chronic oxidative stress is central to the leading causes of mortality in the 21st century-metabolic syndrome and the associated cardiovascular comorbidities. The endurance exercise training that improves mitochondrial capacity and the protective antioxidant cellular system emerges as a universal intervention for mitochondrial dysfunction and resultant comorbidities. Furthermore, exercise might also be a solution to prevent ageing-related degenerative diseases, which are caused by impaired mitochondrial recycling. This review aims to break down the metabolic components of exercise and how they translate to athletic versus metabolically diseased phenotypes. We outline a reciprocal relationship between oxidative metabolism and inflammation, as well as hypoxia. We highlight the importance of oxidative stress for metabolic and antioxidant adaptation. We discuss the relevance of lactate as an indicator of critical exercise intensity, and inferring from its relationship with hypoxia, we suggest the most appropriate mode of exercise for the case of a lost oxidative identity in metabolically inflexible patients. Finally, we propose a reciprocal signalling model that establishes a healthy balance between the glycolytic/proliferative and oxidative/prolonged-ageing phenotypes. This model is malleable to adaptation with oxidative stress in exercise but is also susceptible to maladaptation associated with chronic oxidative stress in disease. Furthermore, mutations of components involved in the transcriptional regulatory mechanisms of mitochondrial metabolism may lead to the development of a cancerous phenotype, which progressively presents as one of the main causes of death, alongside the metabolic syndrome.
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Affiliation(s)
- Filip Kolodziej
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, T12 XF62 Cork, Ireland;
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10
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McNay EC, Pearson-Leary J. GluT4: A central player in hippocampal memory and brain insulin resistance. Exp Neurol 2020; 323:113076. [PMID: 31614121 PMCID: PMC6936336 DOI: 10.1016/j.expneurol.2019.113076] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/19/2019] [Accepted: 10/01/2019] [Indexed: 12/24/2022]
Abstract
Insulin is now well-established as playing multiple roles within the brain, and specifically as regulating hippocampal cognitive processes and metabolism. Impairments to insulin signaling, such as those seen in type 2 diabetes and Alzheimer's disease, are associated with brain hypometabolism and cognitive impairment, but the mechanisms of insulin's central effects are not determined. Several lines of research converge to suggest that the insulin-responsive glucose transporter GluT4 plays a central role in hippocampal memory processes, and that reduced activation of this transporter may underpin the cognitive impairments seen as a consequence of insulin resistance.
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Affiliation(s)
- Ewan C McNay
- Behavioral Neuroscience, University at Albany, Albany, NY, USA.
| | - Jiah Pearson-Leary
- Department of Anesthesiology, Abramson Research Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA
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11
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Chia LY, Evans BA, Mukaida S, Bengtsson T, Hutchinson DS, Sato M. Adrenoceptor regulation of the mechanistic target of rapamycin in muscle and adipose tissue. Br J Pharmacol 2019; 176:2433-2448. [PMID: 30740664 PMCID: PMC6592864 DOI: 10.1111/bph.14616] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/08/2019] [Accepted: 01/21/2019] [Indexed: 12/16/2022] Open
Abstract
A vital role of adrenoceptors in metabolism and energy balance has been well documented in the heart, skeletal muscle, and adipose tissue. It has been only recently demonstrated, however, that activation of the mechanistic target of rapamycin (mTOR) makes a significant contribution to various metabolic and physiological responses to adrenoceptor agonists. mTOR exists as two distinct complexes named mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2) and has been shown to play a critical role in protein synthesis, cell proliferation, hypertrophy, mitochondrial function, and glucose uptake. This review will describe the physiological significance of mTORC1 and 2 as a novel paradigm of adrenoceptor signalling in the heart, skeletal muscle, and adipose tissue. Understanding the detailed signalling cascades of adrenoceptors and how they regulate physiological responses is important for identifying new therapeutic targets and identifying novel therapeutic interventions. LINKED ARTICLES: This article is part of a themed section on Adrenoceptors-New Roles for Old Players. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.14/issuetoc.
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Affiliation(s)
- Ling Yeong Chia
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Bronwyn A. Evans
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Saori Mukaida
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Tore Bengtsson
- Department of Molecular Biosciences, The Wenner‐Gren InstituteStockholm UniversityStockholmSweden
| | - Dana S. Hutchinson
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Masaaki Sato
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
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12
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Civciristov S, Ellisdon AM, Suderman R, Pon CK, Evans BA, Kleifeld O, Charlton SJ, Hlavacek WS, Canals M, Halls ML. Preassembled GPCR signaling complexes mediate distinct cellular responses to ultralow ligand concentrations. Sci Signal 2018; 11:eaan1188. [PMID: 30301787 PMCID: PMC7416780 DOI: 10.1126/scisignal.aan1188] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
G protein-coupled receptors (GPCRs) are the largest class of cell surface signaling proteins, participate in nearly all physiological processes, and are the targets of 30% of marketed drugs. Typically, nanomolar to micromolar concentrations of ligand are used to activate GPCRs in experimental systems. We detected GPCR responses to a wide range of ligand concentrations, from attomolar to millimolar, by measuring GPCR-stimulated production of cyclic adenosine monophosphate (cAMP) with high spatial and temporal resolution. Mathematical modeling showed that femtomolar concentrations of ligand activated, on average, 40% of the cells in a population provided that a cell was activated by one to two binding events. Furthermore, activation of the endogenous β2-adrenergic receptor (β2AR) and muscarinic acetylcholine M3 receptor (M3R) by femtomolar concentrations of ligand in cell lines and human cardiac fibroblasts caused sustained increases in nuclear translocation of extracellular signal-regulated kinase (ERK) and cytosolic protein kinase C (PKC) activity, respectively. These responses were spatially and temporally distinct from those that occurred in response to higher concentrations of ligand and resulted in a distinct cellular proteomic profile. This highly sensitive signaling depended on the GPCRs forming preassembled, higher-order signaling complexes at the plasma membrane. Recognizing that GPCRs respond to ultralow concentrations of neurotransmitters and hormones challenges established paradigms of drug action and provides a previously unappreciated aspect of GPCR activation that is quite distinct from that typically observed with higher ligand concentrations.
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Affiliation(s)
- Srgjan Civciristov
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Andrew M Ellisdon
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Ryan Suderman
- Theoretical Biology and Biophysics Group, Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Cindy K Pon
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Bronwyn A Evans
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Oded Kleifeld
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, Haifa 3200003, Israel
| | - Steven J Charlton
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
- Excellerate Bioscience Ltd, MediCity, Nottingham NG90 6BH, UK
| | - William S Hlavacek
- Theoretical Biology and Biophysics Group, Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Meritxell Canals
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Michelle L Halls
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
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Fischer J, Kleinau G, Rutz C, Zwanziger D, Khajavi N, Müller A, Rehders M, Brix K, Worth CL, Führer D, Krude H, Wiesner B, Schülein R, Biebermann H. Evidence of G-protein-coupled receptor and substrate transporter heteromerization at a single molecule level. Cell Mol Life Sci 2018; 75:2227-2239. [PMID: 29290039 PMCID: PMC11105501 DOI: 10.1007/s00018-017-2728-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 11/17/2017] [Accepted: 12/11/2017] [Indexed: 10/18/2022]
Abstract
G-protein-coupled receptors (GPCRs) can constitute complexes with non-GPCR integral membrane proteins, while such interaction has not been demonstrated at a single molecule level so far. We here investigated the potential interaction between the thyrotropin receptor (TSHR) and the monocarboxylate transporter 8 (MCT8), a member of the major facilitator superfamily (MFS), using fluorescence cross-correlation spectroscopy (FCCS). Both the proteins are expressed endogenously on the basolateral plasma membrane of the thyrocytes and are involved in stimulation of thyroid hormone production and release. Indeed, we demonstrate strong interaction between both the proteins which causes a suppressed activation of Gq/11 by TSH-stimulated TSHR. Thus, we provide not only evidence for a novel interaction between the TSHR and MCT8, but could also prove this interaction on a single molecule level. Moreover, this interaction forces biased signaling at the TSHR. These results are of general interest for both the GPCR and the MFS research fields.
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Affiliation(s)
- Jana Fischer
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Gunnar Kleinau
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Charité - Universitätsmedizin Berlin, 10117, Berlin, Germany
| | - Claudia Rutz
- Protein Trafficking Group, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Denise Zwanziger
- Division of Laboratory Research, Department of Endocrinology, Diabetology and Metabolism, University Hospital Essen, University Duisburg-Essen, 45147, Essen, Germany
| | - Noushafarin Khajavi
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Anne Müller
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Maren Rehders
- Department of Life Sciences and Chemistry, Jacobs University Bremen, 28759, Bremen, Germany
| | - Klaudia Brix
- Department of Life Sciences and Chemistry, Jacobs University Bremen, 28759, Bremen, Germany
| | - Catherine L Worth
- Structural Bioinformatics and Protein Design Group, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125, Berlin, Germany
| | - Dagmar Führer
- Division of Laboratory Research, Department of Endocrinology, Diabetology and Metabolism, University Hospital Essen, University Duisburg-Essen, 45147, Essen, Germany
| | - Heiko Krude
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Burkhard Wiesner
- Protein Trafficking Group, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany
- Cellular Imaging Group, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125, Berlin, Germany
| | - Ralf Schülein
- Protein Trafficking Group, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany.
| | - Heike Biebermann
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany.
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14
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Yu S, Sun L, Jiao Y, Lee LTO. The Role of G Protein-coupled Receptor Kinases in Cancer. Int J Biol Sci 2018; 14:189-203. [PMID: 29483837 PMCID: PMC5821040 DOI: 10.7150/ijbs.22896] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 11/17/2017] [Indexed: 01/14/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are the largest family of plasma membrane receptors. Emerging evidence demonstrates that signaling through GPCRs affects numerous aspects of cancer biology such as vascular remolding, invasion, and migration. Therefore, development of GPCR-targeted drugs could provide a new therapeutic strategy to treating a variety of cancers. G protein-coupled receptor kinases (GRKs) modulate GPCR signaling by interacting with the ligand-activated GPCR and phosphorylating its intracellular domain. This phosphorylation initiates receptor desensitization and internalization, which inhibits downstream signaling pathways related to cancer progression. GRKs can also regulate non-GPCR substrates, resulting in the modulation of a different set of pathophysiological pathways. In this review, we will discuss the role of GRKs in modulating cell signaling and cancer progression, as well as the therapeutic potential of targeting GRKs.
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Affiliation(s)
- Shan Yu
- Centre of Reproduction Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau
| | - Litao Sun
- Department of Ultrasound, The Secondary Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yufei Jiao
- Department of Pathology, The Secondary Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Leo Tsz On Lee
- Centre of Reproduction Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau
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15
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Riddy DM, Delerive P, Summers RJ, Sexton PM, Langmead CJ. G Protein–Coupled Receptors Targeting Insulin Resistance, Obesity, and Type 2 Diabetes Mellitus. Pharmacol Rev 2017; 70:39-67. [DOI: 10.1124/pr.117.014373] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 09/13/2017] [Indexed: 12/18/2022] Open
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16
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Novel Roles for the Insulin-Regulated Glucose Transporter-4 in Hippocampally Dependent Memory. J Neurosci 2017; 36:11851-11864. [PMID: 27881773 DOI: 10.1523/jneurosci.1700-16.2016] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 09/15/2016] [Accepted: 09/20/2016] [Indexed: 11/21/2022] Open
Abstract
The insulin-regulated glucose transporter-4 (GluT4) is critical for insulin- and contractile-mediated glucose uptake in skeletal muscle. GluT4 is also expressed in some hippocampal neurons, but its functional role in the brain is unclear. Several established molecular modulators of memory processing regulate hippocampal GluT4 trafficking and hippocampal memory formation is limited by both glucose metabolism and insulin signaling. Therefore, we hypothesized that hippocampal GluT4 might be involved in memory processes. Here, we show that, in male rats, hippocampal GluT4 translocates to the plasma membrane after memory training and that acute, selective intrahippocampal inhibition of GluT4-mediated glucose transport impaired memory acquisition, but not memory retrieval. Other studies have shown that prolonged systemic GluT4 blockade causes insulin resistance. Unexpectedly, we found that prolonged hippocampal blockade of glucose transport through GluT4-upregulated markers of hippocampal insulin signaling prevented task-associated depletion of hippocampal glucose and enhanced both working and short-term memory while also impairing long-term memory. These effects were accompanied by increased expression of hippocampal AMPA GluR1 subunits and the neuronal GluT3, but decreased expression of hippocampal brain-derived neurotrophic factor, consistent with impaired ability to form long-term memories. Our findings are the first to show the cognitive impact of brain GluT4 modulation. They identify GluT4 as a key regulator of hippocampal memory processing and also suggest differential regulation of GluT4 in the hippocampus from that in peripheral tissues. SIGNIFICANCE STATEMENT The role of insulin-regulated glucose transporter-4 (GluT4) in the brain is unclear. In the current study, we demonstrate that GluT4 is a critical component of hippocampal memory processes. Memory training increased hippocampal GluT4 translocation and memory acquisition was impaired by GluT4 blockade. Unexpectedly, whereas long-term inhibition of GluT4 impaired long-term memory, short-term memory was enhanced. These data further our understanding of the molecular mechanisms of memory and have particular significance for type 2 diabetes (in which GluT4 activity in the periphery is impaired) and Alzheimer's disease (which is linked to impaired brain insulin signaling and for which type 2 diabetes is a key risk factor). Both diseases cause marked impairment of hippocampal memory linked to hippocampal hypometabolism, suggesting the possibility that brain GluT4 dysregulation may be one cause of cognitive impairment in these disease states.
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Seeling T, Čikoš Š, Grybel KJ, Janštová Ž, Pendzialek SM, Schindler M, Špirková A, Santos AN. A Diabetic Pregnancy Alters the Expression of Stress-Related Receptors in Gastrulating Rabbit Blastocyst and in the Reproductive Tract. Reprod Sci 2017; 25:174-184. [DOI: 10.1177/1933719117707055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Tom Seeling
- Department of Anatomy and Cell Biology, Faculty of Medicine, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Štefan Čikoš
- Institute of Animal Physiology, Slovak Academy of Science, Kosice, Slovakia
| | - Katarzyna J. Grybel
- Department of Anatomy and Cell Biology, Faculty of Medicine, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Žofia Janštová
- Institute of Animal Physiology, Slovak Academy of Science, Kosice, Slovakia
| | - S. Mareike Pendzialek
- Department of Anatomy and Cell Biology, Faculty of Medicine, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Maria Schindler
- Department of Anatomy and Cell Biology, Faculty of Medicine, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Alexandra Špirková
- Institute of Animal Physiology, Slovak Academy of Science, Kosice, Slovakia
| | - Anne Navarrete Santos
- Department of Anatomy and Cell Biology, Faculty of Medicine, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
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18
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Benrick A, Kokosar M, Hu M, Larsson M, Maliqueo M, Marcondes RR, Soligo M, Protto V, Jerlhag E, Sazonova A, Behre CJ, Højlund K, Thorén P, Stener-Victorin E. Autonomic nervous system activation mediates the increase in whole-body glucose uptake in response to electroacupuncture. FASEB J 2017; 31:3288-3297. [PMID: 28404742 DOI: 10.1096/fj.201601381r] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 03/27/2017] [Indexed: 12/15/2022]
Abstract
A single bout of low-frequency electroacupuncture (EA) causing muscle contractions increases whole-body glucose uptake in insulin-resistant rats. We explored the underlying mechanism of this finding and whether it can be translated into clinical settings. Changes in glucose infusion rate (GIR) were measured by euglycemic-hyperinsulinemic clamp during and after 45 min of low-frequency EA in 21 overweight/obese women with polycystic ovary syndrome (PCOS) and 21 controls matched for age, weight, and body mass index (experiment 1) and in rats receiving autonomic receptor blockers (experiment 2). GIR was higher after EA in controls and women with PCOS. Plasma serotonin levels and homovanillic acid, markers of vagal activity, decreased in both controls and patients with PCOS. Adipose tissue expression of pro-nerve growth factor (proNGF) decreased, and the mature NGF/proNGF ratio increased after EA in PCOS, but not in controls, suggesting increased sympathetic-driven adipose tissue metabolism. Administration of α-/β-adrenergic receptor blockers in rats blocked the increase in GIR in response to EA. Muscarinic and dopamine receptor antagonist also blocked the response but with slower onset. In conclusion, a single bout of EA increases whole-body glucose uptake by activation of the sympathetic and partly the parasympathetic nervous systems, which could have important clinical implications for the treatment of insulin resistance.-Benrick, A., Kokosar, M., Hu, M., Larsson, M., Maliqueo, M., Marcondes, R. R., Soligo, M., Protto, V., Jerlhag, E., Sazonova, A., Behre, C. J., Højlund, K., Thorén, P., Stener-Victorin, E. Autonomic nervous system activation mediates the increase in whole-body glucose uptake in response to electroacupuncture.
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Affiliation(s)
- Anna Benrick
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,School of Health and Education, University of Skövde, Skövde, Sweden
| | - Milana Kokosar
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Min Hu
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Martin Larsson
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Manuel Maliqueo
- Endocrinology and Metabolism Laboratory, West Division, School of Medicine, University of Chile, Santiago, Chile
| | - Rodrigo Rodrigues Marcondes
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Disciplina de Ginecologia, Laboratório de Ginecologia Estrutural e Molecular (LIM 58), Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Marzia Soligo
- Institute of Translational Pharmacology, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Virginia Protto
- Institute of Translational Pharmacology, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Elisabet Jerlhag
- Department of Pharmacology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Antonina Sazonova
- Department of Obstetrics and Gynecology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Carl Johan Behre
- Department of Cardiology, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Kurt Højlund
- Department of Endocrinology, Odense University Hospital, Odense, Denmark
| | - Peter Thorén
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Kleinau G, Müller A, Biebermann H. Oligomerization of GPCRs involved in endocrine regulation. J Mol Endocrinol 2016; 57:R59-80. [PMID: 27151573 DOI: 10.1530/jme-16-0049] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 05/04/2016] [Indexed: 12/27/2022]
Abstract
More than 800 different human membrane-spanning G-protein-coupled receptors (GPCRs) serve as signal transducers at biological barriers. These receptors are activated by a wide variety of ligands such as peptides, ions and hormones, and are able to activate a diverse set of intracellular signaling pathways. GPCRs are of central importance in endocrine regulation, which underpins the significance of comprehensively studying these receptors and interrelated systems. During the last decade, the capacity for multimerization of GPCRs was found to be a common and functionally relevant property. The interaction between GPCR monomers results in higher order complexes such as homomers (identical receptor subtype) or heteromers (different receptor subtypes), which may be present in a specific and dynamic monomer/oligomer equilibrium. It is widely accepted that the oligomerization of GPCRs is a mechanism for determining the fine-tuning and expansion of cellular processes by modification of ligand action, expression levels, and related signaling outcome. Accordingly, oligomerization provides exciting opportunities to optimize pharmacological treatment with respect to receptor target and tissue selectivity or for the development of diagnostic tools. On the other hand, GPCR heteromerization may be a potential reason for the undesired side effects of pharmacological interventions, faced with numerous and common mutual signaling modifications in heteromeric constellations. Finally, detailed deciphering of the physiological occurrence and relevance of specific GPCR/GPCR-ligand interactions poses a future challenge. This review will tackle the aspects of GPCR oligomerization with specific emphasis on family A GPCRs involved in endocrine regulation, whereby only a subset of these receptors will be discussed in detail.
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Affiliation(s)
- Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
| | - Anne Müller
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
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20
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“Barcode” and Differential Effects of GPCR Phosphorylation by Different GRKs. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2016. [DOI: 10.1007/978-1-4939-3798-1_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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21
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Hodge BA, Wen Y, Riley LA, Zhang X, England JH, Harfmann BD, Schroder EA, Esser KA. The endogenous molecular clock orchestrates the temporal separation of substrate metabolism in skeletal muscle. Skelet Muscle 2015; 5:17. [PMID: 26000164 PMCID: PMC4440511 DOI: 10.1186/s13395-015-0039-5] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/13/2015] [Indexed: 01/04/2023] Open
Abstract
Background Skeletal muscle is a major contributor to whole-body metabolism as it serves as a depot for both glucose and amino acids, and is a highly metabolically active tissue. Within skeletal muscle exists an intrinsic molecular clock mechanism that regulates the timing of physiological processes. A key function of the clock is to regulate the timing of metabolic processes to anticipate time of day changes in environmental conditions. The purpose of this study was to identify metabolic genes that are expressed in a circadian manner and determine if these genes are regulated downstream of the intrinsic molecular clock by assaying gene expression in an inducible skeletal muscle-specific Bmal1 knockout mouse model (iMS-Bmal1−/−). Methods We used circadian statistics to analyze a publicly available, high-resolution time-course skeletal muscle expression dataset. Gene ontology analysis was utilized to identify enriched biological processes in the skeletal muscle circadian transcriptome. We generated a tamoxifen-inducible skeletal muscle-specific Bmal1 knockout mouse model and performed a time-course microarray experiment to identify gene expression changes downstream of the molecular clock. Wheel activity monitoring was used to assess circadian behavioral rhythms in iMS-Bmal1−/− and control iMS-Bmal1+/+ mice. Results The skeletal muscle circadian transcriptome was highly enriched for metabolic processes. Acrophase analysis of circadian metabolic genes revealed a temporal separation of genes involved in substrate utilization and storage over a 24-h period. A number of circadian metabolic genes were differentially expressed in the skeletal muscle of the iMS-Bmal1−/− mice. The iMS-Bmal1−/− mice displayed circadian behavioral rhythms indistinguishable from iMS-Bmal1+/+ mice. We also observed a gene signature indicative of a fast to slow fiber-type shift and a more oxidative skeletal muscle in the iMS-Bmal1−/− model. Conclusions These data provide evidence that the intrinsic molecular clock in skeletal muscle temporally regulates genes involved in the utilization and storage of substrates independent of circadian activity. Disruption of this mechanism caused by phase shifts (that is, social jetlag) or night eating may ultimately diminish skeletal muscle’s ability to efficiently maintain metabolic homeostasis over a 24-h period. Electronic supplementary material The online version of this article (doi:10.1186/s13395-015-0039-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Brian A Hodge
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Yuan Wen
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Lance A Riley
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Xiping Zhang
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Jonathan H England
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Brianna D Harfmann
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Elizabeth A Schroder
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Karyn A Esser
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
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22
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Osborne DM, Pearson-Leary J, McNay EC. The neuroenergetics of stress hormones in the hippocampus and implications for memory. Front Neurosci 2015; 9:164. [PMID: 25999811 PMCID: PMC4422005 DOI: 10.3389/fnins.2015.00164] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 04/21/2015] [Indexed: 12/16/2022] Open
Abstract
Acute stress causes rapid release of norepinephrine (NE) and glucocorticoids (GCs), both of which bind to hippocampal receptors. This release continues, at varying concentrations, for several hours following the stressful event, and has powerful effects on hippocampally-dependent memory that generally promote acquisition and consolidation while impairing retrieval. Several studies have characterized the brain's energy usage both at baseline and during memory processing, but there are few data on energy requirements of memory processes under stressful conditions. Because memory is enhanced by emotional arousal such as during stress, it is likely that molecular memory processes under these conditions differ from those under non-stressful conditions that do not activate the hypothalamic-pituitary-adrenal (HPA) axis. Mobilization of peripheral and central energy stores during stress may increase hippocampal glucose metabolism that enhances salience and detail to facilitate memory enhancement. Several pathways activated by the HPA axis affect neural energy supply and metabolism, and may also prevent detrimental damage associated with chronic stress. We hypothesize that alterations in hippocampal metabolism during stress are key to understanding the effects of stress hormones on hippocampally-dependent memory formation. Second, we suggest that the effects of stress on hippocampal metabolism are bi-directional: within minutes, NE promotes glucose metabolism, while hours into the stress response GCs act to suppress metabolism. These bi-directional effects of NE and GCs on glucose metabolism may occur at least in part through direct modulation of glucose transporter-4. In contrast, chronic stress and prolonged elevation of hippocampal GCs cause chronically suppressed glucose metabolism, excitotoxicity and subsequent memory deficits.
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Affiliation(s)
| | - Jiah Pearson-Leary
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia Philadelphia, PA, USA
| | - Ewan C McNay
- Behavioral Neuroscience, University at Albany Albany, NY, USA ; Biology, University at Albany Albany, NY, USA
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Hsiao WC, Shia KS, Wang YT, Yeh YN, Chang CP, Lin Y, Chen PH, Wu CH, Chao YS, Hung MS. A novel peripheral cannabinoid receptor 1 antagonist, BPR0912, reduces weight independently of food intake and modulates thermogenesis. Diabetes Obes Metab 2015; 17:495-504. [PMID: 25656402 DOI: 10.1111/dom.12447] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 01/09/2015] [Accepted: 01/31/2015] [Indexed: 12/29/2022]
Abstract
AIM To investigate the in vivo metabolic effects of treatment with BPR0912, a novel and potent peripheral cannabinoid receptor 1 (CB1R) antagonist, on both normal mice and diet-induced obese (DIO) mice. METHODS The acute peripheral effects of BPR0912 administration on gastrointestinal transit and energy metabolism in normal mice were investigated. The effects of chronic BPR0912 treatment were compared with those of rimonabant using DIO mice. Alterations to body weight and biochemical and metabolic variables were determined. RESULTS Acute treatment with BPR0912 did not alter food intake or energy metabolism, but efficiently reversed CB1R-mediated gastrointestinal delay. Chronic treatment of DIO mice with BPR0912 showed that BPR0912 exerts a food intake-independent mechanism, which contributes to weight loss. Genes involved in β-oxidation and thermogenesis were upregulated in white adipose tissue (WAT) in addition to increased lipolytic activity, whereas Ucp1 expression was induced in brown adipose tissue (BAT) and body temperature was elevated. Expression of the β2-adrenoceptor was specifically elevated in both WAT and BAT in a manner dependent on the BPR0912 dose. Lastly, chronic BPR0912 treatment was more efficacious than rimonabant in reducing hepatic triglycerides in DIO mice. CONCLUSION BPR0912 exhibits significant in vivo efficacy in inducing food intake-independent weight loss in DIO mice, while tending to reduce their hepatic steatosis. The thermogenic effects of BPR0912, as well as its modulation of protein and gene expression patterns in WAT and BAT, may enhance its efficacy as an anti-obesity agent. The results of the present study support the benefits of the use of peripheral CB1R antagonists to combat metabolic disorders.
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Affiliation(s)
- W-C Hsiao
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli, Taiwan
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24
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Sato M, Dehvari N, Oberg AI, Dallner OS, Sandström AL, Olsen JM, Csikasz RI, Summers RJ, Hutchinson DS, Bengtsson T. Improving type 2 diabetes through a distinct adrenergic signaling pathway involving mTORC2 that mediates glucose uptake in skeletal muscle. Diabetes 2014; 63:4115-29. [PMID: 25008179 DOI: 10.2337/db13-1860] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
There is an increasing worldwide epidemic of type 2 diabetes that poses major health problems. We have identified a novel physiological system that increases glucose uptake in skeletal muscle but not in white adipocytes. Activation of this system improves glucose tolerance in Goto-Kakizaki rats or mice fed a high-fat diet, which are established models for type 2 diabetes. The pathway involves activation of β2-adrenoceptors that increase cAMP levels and activate cAMP-dependent protein kinase, which phosphorylates mammalian target of rapamycin complex 2 (mTORC2) at S2481. The active mTORC2 causes translocation of GLUT4 to the plasma membrane and glucose uptake without the involvement of Akt or AS160. Stimulation of glucose uptake into skeletal muscle after activation of the sympathetic nervous system is likely to be of high physiological relevance because mTORC2 activation was observed at the cellular, tissue, and whole-animal level in rodent and human systems. This signaling pathway provides new opportunities for the treatment of type 2 diabetes.
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MESH Headings
- Animals
- Blood Glucose/metabolism
- Cells, Cultured
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Diabetes Mellitus, Experimental/etiology
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Type 2/etiology
- Diabetes Mellitus, Type 2/metabolism
- Diet, High-Fat/adverse effects
- Glucose Tolerance Test
- Glucose Transporter Type 4/metabolism
- Mechanistic Target of Rapamycin Complex 2
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Multiprotein Complexes/metabolism
- Muscle, Skeletal/metabolism
- Phosphorylation
- Proto-Oncogene Proteins c-akt/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Adrenergic, beta-2/metabolism
- Signal Transduction
- TOR Serine-Threonine Kinases/metabolism
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Affiliation(s)
- Masaaki Sato
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden Department of Pharmacology, Monash University, Clayton, Victoria, Australia Drug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Nodi Dehvari
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Anette I Oberg
- Department of Pharmacology, Monash University, Clayton, Victoria, Australia Drug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Olof S Dallner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden Laboratory of Molecular Genetics, Howard Hughes Medical Institute, The Rockefeller University, New York, NY
| | - Anna L Sandström
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Jessica M Olsen
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Robert I Csikasz
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Roger J Summers
- Department of Pharmacology, Monash University, Clayton, Victoria, Australia Drug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Dana S Hutchinson
- Department of Pharmacology, Monash University, Clayton, Victoria, Australia Drug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Tore Bengtsson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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25
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Rafacho A, Gonçalves-Neto LM, Ferreira FBD, Protzek AOP, Boschero AC, Nunes EA, Zoccal DB. Glucose homoeostasis in rats exposed to acute intermittent hypoxia. Acta Physiol (Oxf) 2013; 209:77-89. [PMID: 23692825 DOI: 10.1111/apha.12118] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Revised: 01/15/2013] [Accepted: 05/15/2013] [Indexed: 11/29/2022]
Abstract
AIM Chronic exposure to intermittent hypoxia commonly induces the activation of sympathetic tonus and the disruption of glucose homoeostasis. However, the effects of exposure to acute intermittent hypoxia (AIH) on glucose homoeostasis are not yet fully elucidated. Herein, we evaluated parameters related to glucose metabolism in rats exposed to AIH. METHODS Male adult rats were submitted to 10 episodes of hypoxia (6% O2 , for 45 s) interspersed with 5-min intervals of normoxia (21%), while the control (CTL) group was kept in normoxia. RESULTS Acute intermittent hypoxia rats presented higher fasting glycaemia, normal insulinaemia, increased lactataemia and similar serum lipid levels, compared to controls (n = 10, P < 0.05). Additionally, AIH rats exhibited increased glucose tolerance (GT) (n = 10, P < 0.05) and augmented insulin sensitivity (IS) (n = 10, P < 0.05). The p-Akt/Akt protein ratio was increased in the muscle, but not in the liver and adipose tissue of AIH rats (n = 6, P < 0.05). The elevated glycaemia in AIH rats was associated with a reduction in the hepatic glycogen content (n = 10, P < 0.05). Moreover, the AIH-induced increase in blood glucose concentration, as well as reduced hepatic glycogen content, was prevented by prior systemic administration of the β-adrenergic antagonist (P < 0.05). The effects of AIH on glycaemia and Akt phosphorylation were transient and not observed after 60 min. CONCLUSIONS We suggest that AIH induces an increase in blood glucose concentration as a result of hepatic glycogenolysis recruitment through sympathetic activation. The augmentation of GT and IS might be attributed, at least in part, to increased β-adrenergic sympathetic stimulation and Akt protein activation in skeletal muscles, leading to a higher glucose availability and utilization.
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Affiliation(s)
- A. Rafacho
- Department of Physiological Sciences; Centre of Biological Sciences; UFSC - Federal University of de Santa Catarina; Florianópolis; Santa Catarina; Brazil
| | - L. M. Gonçalves-Neto
- Department of Physiological Sciences; Centre of Biological Sciences; UFSC - Federal University of de Santa Catarina; Florianópolis; Santa Catarina; Brazil
| | - F. B. D. Ferreira
- Department of Physiological Sciences; Centre of Biological Sciences; UFSC - Federal University of de Santa Catarina; Florianópolis; Santa Catarina; Brazil
| | - A. O. P. Protzek
- Department of Structural and Functional Biology; Institute of Biology; UNICAMP - State University of Campinas; Campinas; São Paulo; Brazil
| | - A. C. Boschero
- Department of Structural and Functional Biology; Institute of Biology; UNICAMP - State University of Campinas; Campinas; São Paulo; Brazil
| | - E. A. Nunes
- Department of Physiological Sciences; Centre of Biological Sciences; UFSC - Federal University of de Santa Catarina; Florianópolis; Santa Catarina; Brazil
| | - D. B. Zoccal
- Department of Physiological Sciences; Centre of Biological Sciences; UFSC - Federal University of de Santa Catarina; Florianópolis; Santa Catarina; Brazil
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26
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β2-adrenoceptor agonists can both stimulate and inhibit glucose uptake in mouse soleus muscle through ligand-directed signalling. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2013; 386:761-73. [PMID: 23564017 DOI: 10.1007/s00210-013-0860-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 03/22/2013] [Indexed: 10/27/2022]
Abstract
The β-adrenoceptor agonists BRL37344 and clenbuterol have opposite effects on glucose uptake in mouse soleus muscle, even though the β2-adrenoceptor mediates both effects. Different agonists may direct the soleus muscle β2-adrenoceptor to different signalling mechanisms. Soleus muscles were incubated with 2-deoxy[1-(14)C]-glucose, β-adrenoceptor agonists, other modulators of cyclic AMP, and inhibitors of intracellular signalling. The adenylyl cyclase activator forskolin (1 μM), the phosphodiesterase inhibitor rolipram (10 μM) and BRL37344 (10, but not 100 or 1,000, nM) increased, whereas clenbuterol (100 nM) decreased, glucose uptake. Forskolin increased, whereas clenbuterol decreased, muscle cyclic AMP content. BRL37344 (10 nM) did not increase cyclic AMP. Nevertheless, protein kinase A (PKA) inhibitors prevented the stimulatory effect of BRL37344. Nanomolar but not micromolar concentrations of adrenaline stimulated glucose uptake. After preincubation of muscles with pertussis toxin (100 ng/ml), 100 nM clenbuterol, 0.1-10 μM adrenaline and 100 nM BRL37344 stimulated glucose uptake. Clenbuterol increased the proportion of phosphorylated to total β2-adrenoceptor. Inhibitors of phosphatidylinositol 3-kinase (PI3K) and the stress-activated mitogen-activated protein kinase (MAPK), but not of the classical MAPK pathway, prevented stimulation of glucose uptake by BRL37344. Elevation of the cyclic AMP content of soleus muscle stimulates glucose uptake. Clenbuterol, and high concentrations of adrenaline and BRL37344 direct the β2-adrenoceptor partly to Gαi, possibly mediated by β2-adrenoceptor phosphorylation. The stimulatory effect of 10 nM BRL37344 requires the activity of PKA, PI3K and p38 MAPK, consistent with BRL37344 directing the β2-adrenoceptor to Gαs. Ligand-directed signalling may explain why β2-adrenoceptor agonists have differing effects on glucose uptake in soleus muscle.
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27
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Boyda HN, Procyshyn RM, Pang CCY, Barr AM. Peripheral adrenoceptors: the impetus behind glucose dysregulation and insulin resistance. J Neuroendocrinol 2013; 25:217-28. [PMID: 23140239 DOI: 10.1111/jne.12002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 10/10/2012] [Accepted: 11/04/2012] [Indexed: 12/20/2022]
Abstract
It is now accepted that several pharmacological drug treatments trigger clinical manifestations of glucose dysregulation, such as hyperglycaemia, glucose intolerance and insulin resistance, in part through poorly understood mechanisms. Persistent sympathoadrenal activation is linked to glucose dysregulation and insulin resistance, both of which significantly increase the risk of emergent endocrinological disorders, including metabolic syndrome and type 2 diabetes mellitus. Through the use of targeted mutagenesis and pharmacological methods, preclinical and clinical research has confirmed physiological glucoregulatory roles for several peripheral α- and β-adrenoceptor subtypes. Adrenoceptor isoforms in the pancreas (α(2A) and β(2) ), skeletal muscle (α(1A) and β(2) ), liver (α(1A & B) and β(2) ) and adipose tissue (α(1A) and β(1 & 3) ) are convincing aetiological targets that account for both immediate and long-lasting alterations in blood glucose homeostasis. Because significant overlap exists between the therapeutic applications of numerous classes of drugs and their associated adverse side-effects, a better understanding of peripheral adrenoceptor-mediated glucose metabolism is thus warranted. Therefore, at the same time as providing a brief review of glucose homeostasis in the periphery, the present review addresses both functional and pathophysiological roles of the mammalian α(1) , α(2) , and β-adrenoceptor isoforms in whole-body glucose turnover. We highlight evidence relating to the clinical use of common adrenergic drugs and their impacts on glucose metabolism.
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Affiliation(s)
- H N Boyda
- Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Vancouver, Canada.
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