1
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Hughson BN. PKG acts in the adult corpora cardiaca to regulate nutrient stress-responsivity through adipokinetic hormone. JOURNAL OF INSECT PHYSIOLOGY 2022; 136:104339. [PMID: 34856210 DOI: 10.1016/j.jinsphys.2021.104339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 11/22/2021] [Accepted: 11/22/2021] [Indexed: 06/13/2023]
Abstract
In Drosophila melanogaster, the adipokinetic hormone (AKH) is a glucagon-like peptide that acts antagonistically with insulin-like peptides to maintain metabolic homeostasis. AKH is biosynthesized in and secreted from the corpora cardiaca (CC). This report describes a CC-specific role for dg2 - which encodes a cGMP-dependent protein kinase (PKG) - as a regulator of AKH during adulthood. Transcriptional silencing of dg2 during adulthood decreased starvation resistance, increased sucrose responsiveness, and decreased whole body lipid content. PKG protein was localized to CC cell membranes, and starvation caused a significant decrease in CC intracellular AKH content. Strikingly, reduced CC-dg2 expression caused a significant decrease in intracellular AKH content in adults fed ad libitum. This work demonstrated that dysregulation of CC-specific dg2 expression during adult life impaired metabolic homeostasis, and that dg2 acted in the CC to regulate systemic AKH activity.
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Affiliation(s)
- Bryon N Hughson
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada; University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 3B2, Canada.
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2
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Hughson BN. The Glucagon-Like Adipokinetic Hormone in Drosophila melanogaster - Biosynthesis and Secretion. Front Physiol 2021; 12:710652. [PMID: 35002748 PMCID: PMC8733639 DOI: 10.3389/fphys.2021.710652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 09/16/2021] [Indexed: 11/13/2022] Open
Abstract
Metabolic homeostasis requires the precise regulation of circulating sugar titers. In mammals, homeostatic control of circulating sugar titers requires the coordinated secretion and systemic activities of glucagon and insulin. Metabolic homeostasis is similarly regulated in Drosophila melanogaster through the glucagon-like adipokinetic hormone (AKH) and the Drosophila insulin-like peptides (DILPs). In flies and mammals, glucagon and AKH are biosynthesized in and secreted from specialized endocrine cells. KATP channels borne on these cells respond to fluctuations in circulating glucose titers and thereby regulate glucagon secretion. The influence of glucagon in the pathogenesis of type 2 diabetes mellitus is now recognized, and a crucial mechanism that regulates glucagon secretion was reported nearly a decade ago. Ongoing efforts to develop D. melanogaster models for metabolic syndrome must build upon this seminal work. These efforts make a critical review of AKH physiology timely. This review focuses on AKH biosynthesis and the regulation of glucose-responsive AKH secretion through changes in CC cell electrical activity. Future directions for AKH research in flies are discussed, including the development of models for hyperglucagonemia and epigenetic inheritance of acquired metabolic traits. Many avenues of AKH physiology remain to be explored and thus present great potential for improving the utility of D. melanogaster in metabolic research.
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Affiliation(s)
- Bryon N. Hughson
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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3
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Längst N, Adler J, Schweigert O, Kleusberg F, Cruz Santos M, Knauer A, Sausbier M, Zeller T, Ruth P, Lukowski R. Cyclic GMP-Dependent Regulation of Vascular Tone and Blood Pressure Involves Cysteine-Rich LIM-Only Protein 4 (CRP4). Int J Mol Sci 2021; 22:9925. [PMID: 34576086 PMCID: PMC8466836 DOI: 10.3390/ijms22189925] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/09/2021] [Accepted: 08/25/2021] [Indexed: 01/14/2023] Open
Abstract
The cysteine-rich LIM-only protein 4 (CRP4), a LIM-domain and zinc finger containing adapter protein, has been implicated as a downstream effector of the second messenger 3',5'-cyclic guanosine monophosphate (cGMP) pathway in multiple cell types, including vascular smooth muscle cells (VSMCs). VSMCs and nitric oxide (NO)-induced cGMP signaling through cGMP-dependent protein kinase type I (cGKI) play fundamental roles in the physiological regulation of vascular tone and arterial blood pressure (BP). However, it remains unclear whether the vasorelaxant actions attributed to the NO/cGMP axis require CRP4. This study uses mice with a targeted deletion of the CRP4 gene (CRP4 KO) to elucidate whether cGMP-elevating agents, which are well known for their vasorelaxant properties, affect vessel tone, and thus, BP through CRP4. Cinaciguat, a NO- and heme-independent activator of the NO-sensitive (soluble) guanylyl cyclase (NO-GC) and NO-releasing agents, relaxed both CRP4-proficient and -deficient aortic ring segments pre-contracted with prostaglandin F2α. However, the magnitude of relaxation was slightly, but significantly, increased in vessels lacking CRP4. Accordingly, CRP4 KO mice presented with hypotonia at baseline, as well as a greater drop in systolic BP in response to the acute administration of cinaciguat, sodium nitroprusside, and carbachol. Mechanistically, loss of CRP4 in VSMCs reduced the Ca2+-sensitivity of the contractile apparatus, possibly involving regulatory proteins, such as myosin phosphatase targeting subunit 1 (MYPT1) and the regulatory light chain of myosin (RLC). In conclusion, the present findings confirm that the adapter protein CRP4 interacts with the NO-GC/cGMP/cGKI pathway in the vasculature. CRP4 seems to be part of a negative feedback loop that eventually fine-tunes the NO-GC/cGMP axis in VSMCs to increase myofilament Ca2+ desensitization and thereby the maximal vasorelaxant effects attained by (selected) cGMP-elevating agents.
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Affiliation(s)
- Natalie Längst
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, 72076 Tuebingen, Germany; (N.L.); (J.A.); (F.K.); (M.C.S.); (A.K.); (M.S.)
| | - Julia Adler
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, 72076 Tuebingen, Germany; (N.L.); (J.A.); (F.K.); (M.C.S.); (A.K.); (M.S.)
| | - Olga Schweigert
- Cardiovascular Systems Medicine and Molecular Translation, University Center of Cardiovascular Science, University Heart & Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany; (O.S.); (T.Z.)
- DZHK, German Center for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, 20251 Hamburg, Germany
| | - Felicia Kleusberg
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, 72076 Tuebingen, Germany; (N.L.); (J.A.); (F.K.); (M.C.S.); (A.K.); (M.S.)
| | - Melanie Cruz Santos
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, 72076 Tuebingen, Germany; (N.L.); (J.A.); (F.K.); (M.C.S.); (A.K.); (M.S.)
| | - Amelie Knauer
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, 72076 Tuebingen, Germany; (N.L.); (J.A.); (F.K.); (M.C.S.); (A.K.); (M.S.)
| | - Matthias Sausbier
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, 72076 Tuebingen, Germany; (N.L.); (J.A.); (F.K.); (M.C.S.); (A.K.); (M.S.)
| | - Tanja Zeller
- Cardiovascular Systems Medicine and Molecular Translation, University Center of Cardiovascular Science, University Heart & Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany; (O.S.); (T.Z.)
- DZHK, German Center for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, 20251 Hamburg, Germany
| | - Peter Ruth
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, 72076 Tuebingen, Germany; (N.L.); (J.A.); (F.K.); (M.C.S.); (A.K.); (M.S.)
| | - Robert Lukowski
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, 72076 Tuebingen, Germany; (N.L.); (J.A.); (F.K.); (M.C.S.); (A.K.); (M.S.)
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4
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Hughson BN, Shimell M, O'Connor MB. AKH Signaling in D. melanogaster Alters Larval Development in a Nutrient-Dependent Manner That Influences Adult Metabolism. Front Physiol 2021; 12:619219. [PMID: 33708137 PMCID: PMC7940354 DOI: 10.3389/fphys.2021.619219] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 01/11/2021] [Indexed: 12/21/2022] Open
Abstract
Metabolism, growth, and development are intrinsically linked, and their coordination is dependent upon inter-organ communication mediated by anabolic, catabolic, and steroid hormones. In Drosophila melanogaster, the corpora cardiaca (CC) influences metabolic homeostasis through adipokinetic hormone (AKH) signaling. AKH has glucagon-like properties and is evolutionarily conserved in mammals as the gonadotropin-releasing hormone, but its role in insect development is unknown. Here we report that AKH signaling alters larval development in a nutrient stress-dependent manner. This activity is regulated by the locus dg2, which encodes a cGMP-dependent protein kinase (PKG). CC-specific downregulation of dg2 expression delayed the developmental transition from larval to pupal life, and altered adult metabolism and behavior. These developmental effects were AKH-dependent, and were observed only in flies that experienced low nutrient stress during larval development. Calcium-mediated vesicle exocytosis regulates ecdysteroid secretion from the prothoracic gland (PG), and we found that AKH signaling increased cytosolic free calcium levels in the PG. We identified a novel pathway through which PKG acts in the CC to communicate metabolic information to the PG via AKH signaling. AKH signaling provides a means whereby larval nutrient stress can alter developmental trajectories into adulthood.
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Affiliation(s)
- Bryon N Hughson
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - MaryJane Shimell
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, United States
| | - Michael B O'Connor
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, United States
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5
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Abstract
The 3',5'-cyclic guanosine monophosphate (cGMP)-dependent protein kinase type I (cGKI aka PKGI) is a major cardiac effector acting downstream of nitric oxide (NO)-sensitive soluble guanylyl cyclase and natriuretic peptides (NPs), which signal through transmembrane guanylyl cyclases. Consistent with the wide distribution of the cGMP-generating guanylyl cyclases, cGKI, which usually elicits its cellular effects by direct phosphorylation of its targets, is present in multiple cardiac cell types including cardiomyocytes (CMs). Although numerous targets of cGMP/cGKI in heart were identified in the past, neither their exact patho-/physiological functions nor cell-type specific roles are clear. Herein, we inform about the current knowledge on the signal transduction downstream of CM cGKI. We believe that better insights into the specific actions of cGMP and cGKI in these cells will help to guide future studies in the search for predictive biomarkers for the response to pharmacological cGMP pathway modulation. In addition, targets downstream of cGMP/cGKI may be exploited for refined and optimized diagnostic and therapeutic strategies in different types of heart disease and their causes. Importantly, key functions of these proteins and particularly sites of regulatory phosphorylation by cGKI should, at least in principle, remain intact, although upstream signaling through the second messenger cGMP is impaired or dysregulated in a stressed or diseased heart state.
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Liu G, Shea CM, Jones JE, Price GM, Warren W, Lonie E, Yan S, Currie MG, Profy AT, Masferrer JL, Zimmer DP. Praliciguat inhibits progression of diabetic nephropathy in ZSF1 rats and suppresses inflammation and apoptosis in human renal proximal tubular cells. Am J Physiol Renal Physiol 2020; 319:F697-F711. [PMID: 32865013 DOI: 10.1152/ajprenal.00003.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Praliciguat, a clinical-stage soluble guanylate cyclase (sGC) stimulator, increases cGMP via the nitric oxide-sGC pathway. Praliciguat has been shown to be renoprotective in rodent models of hypertensive nephropathy and renal fibrosis. In the present study, praliciguat alone and in combination with enalapril attenuated proteinuria in the obese ZSF1 rat model of diabetic nephropathy. Praliciguat monotherapy did not affect hemodynamics. In contrast, enalapril monotherapy lowered blood pressure but did not attenuate proteinuria. Renal expression of genes in pathways involved in inflammation, fibrosis, oxidative stress, and kidney injury was lower in praliciguat-treated obese ZSF1 rats than in obese control rats; fasting glucose and cholesterol were also lower with praliciguat treatment. To gain insight into how tubular mechanisms might contribute to its pharmacological effects on the kidneys, we studied the effects of praliciguat on pathological processes and signaling pathways in cultured human primary renal proximal tubular epithelial cells (RPTCs). Praliciguat inhibited the expression of proinflammatory cytokines and secretion of monocyte chemoattractant protein-1 in tumor necrosis factor-α-challenged RPTCs. Praliciguat treatment also attenuated transforming growth factor-β-mediated apoptosis, changes to a mesenchyme-like cellular phenotype, and phosphorylation of SMAD3 in RPTCs. In conclusion, praliciguat improved proteinuria in the ZSF1 rat model of diabetic nephropathy, and its actions in human RPTCs suggest that tubular effects may contribute to its renal benefits, building upon strong evidence for the role of cGMP signaling in renal health.
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Affiliation(s)
- Guang Liu
- Department of Pharmacology, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Courtney M Shea
- Department of Pharmacology, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Juli E Jones
- Department of Pharmacology, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Gavrielle M Price
- Department of Medical Writing, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - William Warren
- Department of Analytical Pharmacology, Ironwood Pharmaceuticals, Cambridge, Massachusetts
| | - Elisabeth Lonie
- Department of Analytical Pharmacology, Ironwood Pharmaceuticals, Cambridge, Massachusetts
| | - Shu Yan
- Department of Discovery Informatics, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Mark G Currie
- Department of Research Management, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Albert T Profy
- Department of Development Management, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Jaime L Masferrer
- Department of Pharmacology, Cyclerion Therapeutics, Cambridge, Massachusetts
| | - Daniel P Zimmer
- Department of Pharmacology, Cyclerion Therapeutics, Cambridge, Massachusetts
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7
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Vega SC, Leiss V, Piekorz R, Calaminus C, Pexa K, Vuozzo M, Schmid AM, Devanathan V, Kesenheimer C, Pichler BJ, Beer-Hammer S, Nürnberg B. Selective protection of murine cerebral G i/o-proteins from inactivation by parenterally injected pertussis toxin. J Mol Med (Berl) 2019; 98:97-110. [PMID: 31811326 DOI: 10.1007/s00109-019-01854-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 10/30/2019] [Accepted: 11/12/2019] [Indexed: 12/18/2022]
Abstract
Pertussis toxin (PTX) is a potent virulence factor in patients suffering from whooping cough, but in its detoxified version, it is applied for vaccination. It is thought to contribute to the pathology of the disease including various CNS malfunctions. Based on its enzymatic activity, PTX disrupts GPCR-dependent signaling by modifying the α-subunit of heterotrimeric Gi/o-proteins. It is also extensively used as a research tool to study neuronal functions in vivo and in vitro. However, data demonstrating the penetration of PTX from the blood into the brain are missing. Here, we examined the Gαi/o-modifying activity of PTX in murine brains after its parenteral application. Ex vivo biodistribution analysis of [124I]-PTX displayed poor distribution to the brain while relatively high concentrations were visible in the pancreas. PTX affected CNS and endocrine functions of the pancreas as shown by open-field and glucose tolerance tests, respectively. However, while pancreatic islet Gαi/o-proteins were modified, their neuronal counterparts in brain tissue were resistant towards PTX as indicated by different autoradiographic and immunoblot SDS-PAGE analyses. In contrast, PTX easily modified brain Gαi/o-proteins ex vivo. An attempt to increase BBB permeability by application of hypertonic mannitol did not show PTX activity on neuronal G proteins. Consistent with these findings, in vivo MRI analysis did not point to an increased blood-brain barrier (BBB) permeability following PTX treatment. Our data demonstrate that the CNS is protected from PTX. Thus, we hypothesize that the BBB hinders PTX to penetrate into the CNS and to deliver its enzymatic activity to brain Gαi/o-proteins. KEY MESSAGES: i.p. applied PTX is poorly retained in the brain while reaches high concentration in the pancreas. Pancreatic islet Gαi/o- but not cerebral Gαi/o-proteins are modified by i.p. administered PTX. Gαi/o-proteins from isolated cerebral cell membranes were easily modified by PTX ex vivo. CNS is protected from i.p. administered PTX. PTX does not permeabilize the BBB.
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Affiliation(s)
- Salvador Castaneda Vega
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen and University Medical Center, Tübingen, Germany
- Department of Nuclear Medicine and Clinical Molecular Imaging, Eberhard Karls University, Tübingen, Germany
| | - Veronika Leiss
- Department of Pharmacology and Experimental Therapy, Institute for Experimental and Clinical Pharmacology and Toxicology, Interfaculty Center for Pharmacogenomics and Drug Research, Eberhard Karls University Tübingen, 72074, Tübingen, Germany
| | - Roland Piekorz
- Institute for Biochemistry and Molecular Biology II, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Carsten Calaminus
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen and University Medical Center, Tübingen, Germany
| | - Katja Pexa
- Institute for Biochemistry and Molecular Biology II, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Marta Vuozzo
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen and University Medical Center, Tübingen, Germany
| | - Andreas M Schmid
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen and University Medical Center, Tübingen, Germany
| | - Vasudharani Devanathan
- Department of Pharmacology and Experimental Therapy, Institute for Experimental and Clinical Pharmacology and Toxicology, Interfaculty Center for Pharmacogenomics and Drug Research, Eberhard Karls University Tübingen, 72074, Tübingen, Germany
- Neuroscience Lab, Department of Biology, Indian Institute of Science Education and Research (IISER), Tirupati, India
| | - Christian Kesenheimer
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen and University Medical Center, Tübingen, Germany
| | - Bernd J Pichler
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen and University Medical Center, Tübingen, Germany
- Department of Nuclear Medicine and Clinical Molecular Imaging, Eberhard Karls University, Tübingen, Germany
| | - Sandra Beer-Hammer
- Department of Pharmacology and Experimental Therapy, Institute for Experimental and Clinical Pharmacology and Toxicology, Interfaculty Center for Pharmacogenomics and Drug Research, Eberhard Karls University Tübingen, 72074, Tübingen, Germany
| | - Bernd Nürnberg
- Department of Pharmacology and Experimental Therapy, Institute for Experimental and Clinical Pharmacology and Toxicology, Interfaculty Center for Pharmacogenomics and Drug Research, Eberhard Karls University Tübingen, 72074, Tübingen, Germany.
- Department of Toxicology, Institute for Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Tübingen, and University Medical Center, Tübingen, Germany.
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8
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Undank S, Kaiser J, Sikimic J, Düfer M, Krippeit-Drews P, Drews G. Atrial Natriuretic Peptide Affects Stimulus-Secretion Coupling of Pancreatic β-Cells. Diabetes 2017; 66:2840-2848. [PMID: 28864549 DOI: 10.2337/db17-0392] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 08/24/2017] [Indexed: 11/13/2022]
Abstract
Atrial natriuretic peptide (ANP) influences glucose homeostasis and possibly acts as a link between the cardiovascular system and metabolism, especially in metabolic disorders like diabetes. The current study evaluated effects of ANP on β-cell function by the use of a β-cell-specific knockout of the ANP receptor with guanylate cyclase activity (βGC-A-KO). ANP augmented insulin secretion at the threshold glucose concentration of 6 mmol/L and decreased KATP single-channel activity in β-cells of control mice but not of βGC-A-KO mice. In wild-type β-cells but not β-cells lacking functional KATP channels (SUR1-KO), ANP increased electrical activity, suggesting no involvement of other ion channels. At 6 mmol/L glucose, ANP readily elicited Ca2+ influx in control β-cells. This effect was blunted in β-cells of βGC-A-KO mice, and the maximal cytosolic Ca2+ concentration was lower. Experiments with inhibitors of protein kinase G (PKG), protein kinase A (PKA), phosphodiesterase 3B (PDE3B), and a membrane-permeable cyclic guanosine monophosphate (cGMP) analog on KATP channel activity and insulin secretion point to participation of the cGMP/PKG and cAMP/PKA/Epac (exchange protein directly activated by cAMP) directly activated by cAMP Epac pathways in the effects of ANP on β-cell function; the latter seems to prevail. Moreover, ANP potentiated the effect of glucagon-like peptide 1 (GLP-1) on glucose-induced insulin secretion, which could be caused by a cGMP-mediated inhibition of PDE3B, which in turn reduces cAMP degradation.
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Affiliation(s)
- Sabrina Undank
- Institute of Pharmacy, Department of Pharmacology, University of Tübingen, Tübingen, Germany
| | - Julia Kaiser
- Institute of Pharmacy, Department of Pharmacology, University of Tübingen, Tübingen, Germany
| | - Jelena Sikimic
- Institute of Pharmacy, Department of Pharmacology, University of Tübingen, Tübingen, Germany
| | - Martina Düfer
- Department of Pharmaceutical and Medical Chemistry, University of Münster, Münster, Germany
| | - Peter Krippeit-Drews
- Institute of Pharmacy, Department of Pharmacology, University of Tübingen, Tübingen, Germany
| | - Gisela Drews
- Institute of Pharmacy, Department of Pharmacology, University of Tübingen, Tübingen, Germany
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Steudel FA, Mohr CJ, Stegen B, Nguyen HY, Barnert A, Steinle M, Beer‐Hammer S, Koch P, Lo W, Schroth W, Hoppe R, Brauch H, Ruth P, Huber SM, Lukowski R. SK4 channels modulate Ca 2+ signalling and cell cycle progression in murine breast cancer. Mol Oncol 2017; 11:1172-1188. [PMID: 28557306 PMCID: PMC5579333 DOI: 10.1002/1878-0261.12087] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 04/27/2017] [Accepted: 05/16/2017] [Indexed: 01/08/2023] Open
Abstract
Oncogenic signalling via Ca2+ -activated K+ channels of intermediate conductance (SK4, also known as KCa 3.1 or IK) has been implicated in different cancer entities including breast cancer. Yet, the role of endogenous SK4 channels for tumorigenesis is unclear. Herein, we generated SK4-negative tumours by crossing SK4-deficient (SK4 KO) mice to the polyoma middle T-antigen (PyMT) and epidermal growth factor receptor 2 (cNeu) breast cancer models in which oncogene expression is driven by the retroviral promoter MMTV. Survival parameters and tumour progression were studied in cancer-prone SK4 KO in comparison with wild-type (WT) mice and in a syngeneic orthotopic mouse model following transplantation of SK4-negative or WT tumour cells. SK4 activity was modulated by genetic or pharmacological means using the SK4 inhibitor TRAM-34 in order to establish the role of breast tumour SK4 for cell growth, electrophysiological signalling, and [Ca2+ ]i oscillations. Ablation of SK4 and TRAM-34 treatment reduced the SK4-generated current fraction, growth factor-dependent Ca2+ entry, cell cycle progression and the proliferation rate of MMTV-PyMT tumour cells. In vivo, PyMT oncogene-driven tumorigenesis was only marginally affected by the global lack of SK4, whereas tumour progression was significantly delayed after orthotopic implantation of MMTV-PyMT SK4 KO breast tumour cells. However, overall survival and progression-free survival time in the MMTV-cNeu mouse model were significantly extended in the absence of SK4. Collectively, our data from murine breast cancer models indicate that SK4 activity is crucial for cell cycle control. Thus, the modulation of this channel should be further investigated towards a potential improvement of existing antitumour strategies in human breast cancer.
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Affiliation(s)
- Friederike A. Steudel
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
| | - Corinna J. Mohr
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
- Dr. Margarete Fischer‐Bosch‐Institute of Clinical PharmacologyStuttgart and University of TuebingenGermany
| | - Benjamin Stegen
- Department of Radiation OncologyUniversity of TuebingenGermany
| | - Hoang Y. Nguyen
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
| | - Andrea Barnert
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
| | - Marc Steinle
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
| | - Sandra Beer‐Hammer
- Department of Pharmacology and Experimental TherapyInstitute of Experimental and Clinical Pharmacology and ToxicologyUniversity Hospital TuebingenGermany
| | - Pierre Koch
- Pharmaceutical and Medicinal ChemistryInstitute of PharmacyUniversity of TuebingenGermany
| | - Wing‐Yee Lo
- Dr. Margarete Fischer‐Bosch‐Institute of Clinical PharmacologyStuttgart and University of TuebingenGermany
| | - Werner Schroth
- Dr. Margarete Fischer‐Bosch‐Institute of Clinical PharmacologyStuttgart and University of TuebingenGermany
| | - Reiner Hoppe
- Dr. Margarete Fischer‐Bosch‐Institute of Clinical PharmacologyStuttgart and University of TuebingenGermany
| | - Hiltrud Brauch
- Dr. Margarete Fischer‐Bosch‐Institute of Clinical PharmacologyStuttgart and University of TuebingenGermany
- German Cancer Consortium (DKTK)German Cancer Research Center (DKFZ)HeidelbergGermany
| | - Peter Ruth
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
| | | | - Robert Lukowski
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
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10
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Wong JC, Vo V, Gorjala P, Fiscus RR. Pancreatic-β-cell survival and proliferation are promoted by protein kinase G type Iα and downstream regulation of AKT/FOXO1. Diab Vasc Dis Res 2017. [PMID: 28631500 DOI: 10.1177/1479164117713947] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Early studies showed nitric oxide as a pro-inflammatory-cytokine-induced toxin involved in pancreatic β-cell destruction during pathogenesis of type-1 diabetes. However, nitric oxide has both cytotoxic and cytoprotective effects on mammalian cells, depending on concentration and micro-environmental surroundings. Our studies have shown that low/physiological-level nitric oxide selectively activates protein kinase G type Iα isoform, promoting cytoprotective/pro-cell-survival effects in many cell types. In bone marrow-derived stromal/mesenchymal stem cells, protein kinase G type Iα mediates autocrine effects of nitric oxide and atrial natriuretic peptide, promoting DNA-synthesis/proliferation and cell survival. In this study, endothelial nitric oxide synthase/neuronal nitric oxide synthase inhibitor L-NIO (L-N(5)-(1-iminoethyl)ornithine), soluble guanylyl cyclase inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3,-a] quinoxalin-1-one), atrial natriuretic peptide-receptor inhibitor A71915 and protein kinase G type Iα kinase activity inhibitor DT-2 all increased apoptosis and decreased insulin secretion in RINm5F pancreatic β-cells, suggesting autocrine regulatory role for endogenous nitric oxide- and atrial natriuretic peptide-induced activation of protein kinase G type Iα. In four pancreatic β-cell lines, Beta-TC-6, RINm5F, INS-1 and 1.1B4, protein kinase G type Iα small-interfering RNA decreased phospho-serine-239-VASP (indicator of endogenous protein kinase G type Iα kinase activity), increased apoptosis and decreased proliferation. In protein kinase G type Iα-knockdown β-cell lines, expressions of phospho-protein kinase B (PKB/AKT) (AKT), phospho-Forkhead box protein O1 (FOXO1) (transcriptional repressor of pancreas duodenum homobox-1) and pancreas duodenum homobox-1 were decreased, suppressing proliferation and survival in pancreatic β-cells. The data suggest autocrine nitric oxide/atrial natriuretic peptide-induced activation of protein kinase G type Iα/p-AKT/p-FOXO1 promotes survival and proliferation in pancreatic β-cells, providing therapeutic implications for development of new therapeutic agents for diabetes.
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Affiliation(s)
- Janica C Wong
- 1 Department of Biomedical Sciences, College of Medicine, Roseman University of Health Sciences, Las Vegas, NV, USA
- 2 Pharmaceutical Sciences, College of Pharmacy, Roseman University of Health Sciences, Henderson, NV, USA
| | - Van Vo
- 1 Department of Biomedical Sciences, College of Medicine, Roseman University of Health Sciences, Las Vegas, NV, USA
- 2 Pharmaceutical Sciences, College of Pharmacy, Roseman University of Health Sciences, Henderson, NV, USA
| | - Priyatham Gorjala
- 1 Department of Biomedical Sciences, College of Medicine, Roseman University of Health Sciences, Las Vegas, NV, USA
- 2 Pharmaceutical Sciences, College of Pharmacy, Roseman University of Health Sciences, Henderson, NV, USA
| | - Ronald R Fiscus
- 1 Department of Biomedical Sciences, College of Medicine, Roseman University of Health Sciences, Las Vegas, NV, USA
- 2 Pharmaceutical Sciences, College of Pharmacy, Roseman University of Health Sciences, Henderson, NV, USA
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11
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Illison J, Tian L, McClafferty H, Werno M, Chamberlain LH, Leiss V, Sassmann A, Offermanns S, Ruth P, Shipston MJ, Lukowski R. Obesogenic and Diabetogenic Effects of High-Calorie Nutrition Require Adipocyte BK Channels. Diabetes 2016; 65:3621-3635. [PMID: 27605626 DOI: 10.2337/db16-0245] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 08/16/2016] [Indexed: 11/13/2022]
Abstract
Elevated adipose tissue expression of the Ca2+- and voltage-activated K+ (BK) channel was identified in morbidly obese men carrying a BK gene variant, supporting the hypothesis that K+ channels affect the metabolic responses of fat cells to nutrients. To establish the role of endogenous BKs in fat cell maturation, storage of excess dietary fat, and body weight (BW) gain, we studied a gene-targeted mouse model with global ablation of the BK channel (BKL1/L1) and adipocyte-specific BK-deficient (adipoqBKL1/L2) mice. Global BK deficiency afforded protection from BW gain and excessive fat accumulation induced by a high-fat diet (HFD). Expansion of white adipose tissue-derived epididymal BKL1/L1 preadipocytes and their differentiation to lipid-filled mature adipocytes in vitro, however, were improved. Moreover, BW gain and total fat masses of usually superobese ob/ob mice were significantly attenuated in the absence of BK, together supporting a central or peripheral role for BKs in the regulatory system that controls adipose tissue and weight. Accordingly, HFD-fed adipoqBKL1/L2 mutant mice presented with a reduced total BW and overall body fat mass, smaller adipocytes, and reduced leptin levels. Protection from pathological weight gain in the absence of adipocyte BKs was beneficial for glucose handling and related to an increase in body core temperature as a result of higher levels of uncoupling protein 1 and a low abundance of the proinflammatory interleukin-6, a common risk factor for diabetes and metabolic abnormalities. This suggests that adipocyte BK activity is at least partially responsible for excessive BW gain under high-calorie conditions, suggesting that BK channels are promising drug targets for pharmacotherapy of metabolic disorders and obesity.
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Affiliation(s)
- Julia Illison
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, Tübingen, Germany
| | - Lijun Tian
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, U.K
| | - Heather McClafferty
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, U.K
| | - Martin Werno
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Strathclyde University, Glasgow, U.K
| | - Luke H Chamberlain
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Strathclyde University, Glasgow, U.K
| | - Veronika Leiss
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, University Hospital Tübingen, Tübingen, Germany
| | - Antonia Sassmann
- Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Stefan Offermanns
- Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Peter Ruth
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, Tübingen, Germany
| | - Michael J Shipston
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, U.K
| | - Robert Lukowski
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, Tübingen, Germany
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12
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Brennenstuhl C, Tanimoto N, Burkard M, Wagner R, Bolz S, Trifunovic D, Kabagema-Bilan C, Paquet-Durand F, Beck SC, Huber G, Seeliger MW, Ruth P, Wissinger B, Lukowski R. Targeted ablation of the Pde6h gene in mice reveals cross-species differences in cone and rod phototransduction protein isoform inventory. J Biol Chem 2015; 290:10242-55. [PMID: 25739440 DOI: 10.1074/jbc.m114.611921] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Indexed: 11/06/2022] Open
Abstract
Phosphodiesterase-6 (PDE6) is a multisubunit enzyme that plays a key role in the visual transduction cascade in rod and cone photoreceptors. Each type of photoreceptor utilizes discrete catalytic and inhibitory PDE6 subunits to fulfill its physiological tasks, i.e. the degradation of cyclic guanosine-3',5'-monophosphate at specifically tuned rates and kinetics. Recently, the human PDE6H gene was identified as a novel locus for autosomal recessive (incomplete) color blindness. However, the three different classes of cones were not affected to the same extent. Short wave cone function was more preserved than middle and long wave cone function indicating that some basic regulation of the PDE6 multisubunit enzyme was maintained albeit by a unknown mechanism. To study normal and disease-related functions of cone Pde6h in vivo, we generated Pde6h knock-out (Pde6h(-/-)) mice. Expression of PDE6H in murine eyes was restricted to both outer segments and synaptic terminals of short and long/middle cone photoreceptors, whereas Pde6h(-/-) retinae remained PDE6H-negative. Combined in vivo assessment of retinal morphology with histomorphological analyses revealed a normal overall integrity of the retinal organization and an unaltered distribution of the different cone photoreceptor subtypes upon Pde6h ablation. In contrast to human patients, our electroretinographic examinations of Pde6h(-/-) mice suggest no defects in cone/rod-driven retinal signaling and therefore preserved visual functions. To this end, we were able to demonstrate the presence of rod PDE6G in cones indicating functional substitution of PDE6. The disparities between human and murine phenotypes caused by mutant Pde6h/PDE6H suggest species-to-species differences in the vulnerability of biochemical and neurosensory pathways of the visual signal transduction system.
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Affiliation(s)
- Christina Brennenstuhl
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | | | - Markus Burkard
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | - Rebecca Wagner
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | | | | | - Clement Kabagema-Bilan
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | | | | | | | | | - Peter Ruth
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | - Bernd Wissinger
- the Molecular Genetics Laboratory, Centre for Ophthalmology, University of Tuebingen, 72076 Tuebingen, Germany
| | - Robert Lukowski
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy,
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13
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Leiss V, Flockerzie K, Novakovic A, Rath M, Schönsiegel A, Birnbaumer L, Schürmann A, Harteneck C, Nürnberg B. Insulin secretion stimulated by L-arginine and its metabolite L-ornithine depends on Gα(i2). Am J Physiol Endocrinol Metab 2014; 307:E800-12. [PMID: 25205820 PMCID: PMC4216945 DOI: 10.1152/ajpendo.00337.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bordetella pertussis toxin (PTx), also known as islet-activating protein, induces insulin secretion by ADP-ribosylation of inhibitory G proteins. PTx-induced insulin secretion may result either from inactivation of Gα(o) proteins or from combined inactivation of Gα(o), Gα(i1), Gα(i2), and Gα(i3) isoforms. However, the specific role of Gα(i2) in pancreatic β-cells still remains unknown. In global (Gα(i2)(-/-)) and β-cell-specific (Gα(i2)(βcko)) gene-targeted Gα(i2) mouse models, we studied glucose homeostasis and islet functions. Insulin secretion experiments and intracellular Ca²⁺ measurements were used to characterize Gα(i2) function in vitro. Gα(i2)(-/-) and Gα(i2)(βcko) mice showed an unexpected metabolic phenotype, i.e., significantly lower plasma insulin levels upon intraperitoneal glucose challenge in Gα(i2)(-/-) and Gα(i2)(βcko) mice, whereas plasma glucose concentrations were unchanged in Gα(i2)(-/-) but significantly increased in Gα(i2)(βcko) mice. These findings indicate a novel albeit unexpected role for Gα(i2) in the expression, turnover, and/or release of insulin from islets. Detection of insulin secretion in isolated islets did not show differences in response to high (16 mM) glucose concentrations between control and β-cell-specific Gα(i2)-deficient mice. In contrast, the two- to threefold increase in insulin secretion evoked by L-arginine or L-ornithine (in the presence of 16 mM glucose) was significantly reduced in islets lacking Gα(i2). In accord with a reduced level of insulin secretion, intracellular calcium concentrations induced by the agonistic amino acid L-arginine did not reach control levels in β-cells. The presented analysis of gene-targeted mice provides novel insights in the role of β-cell Gα(i2) showing that amino acid-induced insulin-release depends on Gα(i2).
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MESH Headings
- Animals
- Arginine/metabolism
- Blood Glucose/analysis
- Calcium Signaling
- Crosses, Genetic
- Down-Regulation
- Fluorescent Antibody Technique
- GTP-Binding Protein alpha Subunit, Gi2/agonists
- GTP-Binding Protein alpha Subunit, Gi2/genetics
- GTP-Binding Protein alpha Subunit, Gi2/metabolism
- GTP-Binding Protein alpha Subunits, Gi-Go/agonists
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Hyperglycemia/blood
- Hyperglycemia/metabolism
- Hyperglycemia/prevention & control
- Hypoglycemia/blood
- Hypoglycemia/metabolism
- Hypoglycemia/prevention & control
- Insulin/blood
- Insulin/metabolism
- Insulin Secretion
- Islets of Langerhans/cytology
- Islets of Langerhans/metabolism
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Ornithine/blood
- Ornithine/metabolism
- Specific Pathogen-Free Organisms
- Tissue Culture Techniques
- Up-Regulation
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Affiliation(s)
- Veronika Leiss
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany
| | - Katarina Flockerzie
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany
| | - Ana Novakovic
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany
| | - Michaela Rath
- Department of Experimental Diabetology, German Institute of Human Nutrition, Potsdam-Rehbrücke, Nuthetal, Germany
| | - Annika Schönsiegel
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany
| | - Lutz Birnbaumer
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health/Department of Health and Human Services, Durham, North Carolina
| | - Annette Schürmann
- Department of Experimental Diabetology, German Institute of Human Nutrition, Potsdam-Rehbrücke, Nuthetal, Germany
| | - Christian Harteneck
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany
| | - Bernd Nürnberg
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany;
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14
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Leiss V, Illison J, Domes K, Hofmann F, Lukowski R. Expression of cGMP-dependent protein kinase type I in mature white adipocytes. Biochem Biophys Res Commun 2014; 452:151-6. [DOI: 10.1016/j.bbrc.2014.08.071] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 08/15/2014] [Indexed: 01/01/2023]
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15
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Roles of cGMP-dependent protein kinase I (cGKI) and PDE5 in the regulation of Ang II-induced cardiac hypertrophy and fibrosis. Proc Natl Acad Sci U S A 2014; 111:12925-9. [PMID: 25139994 DOI: 10.1073/pnas.1414364111] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Conflicting results have been reported for the roles of cGMP and cGMP-dependent protein kinase I (cGKI) in various pathological conditions leading to cardiac hypertrophy and fibrosis. A cardioprotective effect of cGMP/cGKI has been reported in whole animals and isolated cardiomyocytes, but recent evidence from a mouse model expressing cGKIβ only in smooth muscle (βRM) but not in cardiomyocytes, endothelial cells, or fibroblasts has forced a reevaluation of the requirement for cGKI activity in the cardiomyocyte antihypertrophic effects of cGMP. In particular, βRM mice developed the same hypertrophy as WT controls when subjected to thoracic aortic constriction or isoproterenol infusion. Here, we challenged βRM and WT (Ctr) littermate control mice with angiotensin II (AII) infusion (7 d; 2 mg ⋅ kg(-1) ⋅ d(-1)) to induce hypertrophy. Both genotypes developed cardiac hypertrophy, which was more pronounced in Ctr animals. Cardiomyocyte size and interstitial fibrosis were increased equally in both genotypes. Addition of sildenafil, a phosphodiesterase 5 (PDE5) inhibitor, in the drinking water had a small effect in reducing myocyte hypertrophy in WT mice and no effect in βRM mice. However, sildenafil substantially blocked the increase in collagen I, fibronectin 1, TGFβ, and CTGF mRNA in Ctr but not in βRM hearts. These data indicate that, for the initial phase of AII-induced cardiac hypertrophy, lack of cardiomyocyte cGKI activity does not worsen hypertrophic growth. However, expression of cGKI in one or more cell types other than smooth muscle is necessary to allow the antifibrotic effect of sildenafil.
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16
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Turning on cGMP-dependent pathways to treat cardiac dysfunctions: boom, bust, and beyond. Trends Pharmacol Sci 2014; 35:404-13. [PMID: 24948380 DOI: 10.1016/j.tips.2014.05.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 05/08/2014] [Accepted: 05/14/2014] [Indexed: 12/16/2022]
Abstract
cGMP inhibits hypertrophy, decreases fibrosis, and protects against cardiac ischemia-reperfusion (I/R) injury. Gene-targeting studies have not defined a clear role for its major downstream effector, cGMP-dependent protein kinase I (cGKI), in cardiac hypertrophy, but do implicate cGMP-cGKI signaling in fibrosis and I/R injury. No direct cGKI activators have advanced to clinical trials, whereas cardiac trials of agents that modulate cGMP via particulate or soluble guanylyl cyclases (GCs) and phosphodiesterase 5 (PDE5) are ongoing. Here we review concerns arising from preclinical and clinical studies that question whether targeting the cGMP pathway remains an encouraging concept for management of heart dysfunction. So far, trial results for GC modulators are inconclusive, and sildenafil, a PDE5 inhibitor, although cardioprotective in mouse models, has not shown positive clinical results. Preclinical cardioprotection observed for sildenafil may result from inhibition of PDE5 in non-cardiomyocytes or off-target effects, possibly on PDE1C. On the basis of such mechanistic considerations, re-evaluation of the cellular localization of drug target(s) and intervention protocols for cGMP-elevating agents may be needed.
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17
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Zhang L, Lukowski R, Gaertner F, Lorenz M, Legate KR, Domes K, Angermeier E, Hofmann F, Massberg S. Anti-interleukin-6 therapy for treatment of high platelet counts in cGMP-dependent protein kinase I gene-targeted mice. BMC Pharmacol Toxicol 2013. [PMCID: PMC3765637 DOI: 10.1186/2050-6511-14-s1-p80] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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18
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Pfeifer A, Kilić A, Hoffmann LS. Regulation of metabolism by cGMP. Pharmacol Ther 2013; 140:81-91. [PMID: 23756133 DOI: 10.1016/j.pharmthera.2013.06.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 05/24/2013] [Indexed: 01/16/2023]
Abstract
The second messenger cyclic guanosine monophosphate (cGMP) mediates the physiological effects of nitric oxide and natriuretic peptides in a broad spectrum of tissues and cells. So far, the major focus of research on cGMP lay on the cardiovascular system. Recent evidence suggests that cGMP also plays a major role in the regulation of cellular and whole-body metabolism. Here, we focus on the role of cGMP in adipose tissue. In addition, other organs important for the regulation of metabolism and their regulation by cGMP are discussed. Targeting the cGMP signaling pathway could be an exciting approach for the regulation of energy expenditure and the treatment of obesity.
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Affiliation(s)
- Alexander Pfeifer
- Institute of Pharmacology and Toxicology, Biomedical Center, University of Bonn, Germany.
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19
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Mitschke MM, Hoffmann LS, Gnad T, Scholz D, Kruithoff K, Mayer P, Haas B, Sassmann A, Pfeifer A, Kilic A. Increased cGMP promotes healthy expansion and browning of white adipose tissue. FASEB J 2013; 27:1621-30. [PMID: 23303211 DOI: 10.1096/fj.12-221580] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
With more than half a billion individuals affected worldwide, obesity has reached pandemic proportions. Development of "brown-like" or "brite" adipocytes within white adipose tissue (WAT) has potential antiobesity and insulin-sensitizing effects. We investigated the role of cyclic GMP (cGMP) signaling, focusing on cGMP-dependent protein kinase I (PKGI) in WAT. PKGI is expressed in murine WAT, primary adipocytes, and 3T3-L1. Treatment of adipocytes with cGMP resulted in increased adipogenesis, with a 54% increase in expression of peroxisome proliferator-activated receptor-γ. Lentiviral overexpression of PKGI further increased adipogenesis, whereas loss of PKGI significantly reduced adipogenic differentiation. In addition to adipogenic effects, PKGI had an antihypertrophic and anti-inflammatory effect via RhoA phosphorylation and reduction of proinflammatory adipokine expression. Moreover, PKGI induced a 4.3-fold increase in abundance of UCP-1 and the development of a brown-like thermogenic program in primary adipocytes. Notably, treatment of C57BL/6 mice with phosphodiesterase inhibitor sildenafil (12 mg/kg/d) for 7 d caused 4.6-fold increase in uncoupling protein-1 expression and promoted establishment of a brown fat cell-like phenotype ("browning") of WAT in vivo. Taken together, PKGI is a key regulator of cell size, adipokine secretion and browning of white fat depots and thus could be a valuable target in developing novel treatments for obesity.
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20
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Abstract
cGMP-dependent protein kinases (cGK) are serine/threonine kinases that are widely distributed in eukaryotes. Two genes-prkg1 and prkg2-code for cGKs, namely, cGKI and cGKII. In mammals, two isozymes, cGKIα and cGKIβ, are generated from the prkg1 gene. The cGKI isozymes are prominent in all types of smooth muscle, platelets, and specific neuronal areas such as cerebellar Purkinje cells, hippocampal neurons, and the lateral amygdala. The cGKII prevails in the secretory epithelium of the small intestine, the juxtaglomerular cells, the adrenal cortex, the chondrocytes, and in the nucleus suprachiasmaticus. Both cGKs are major downstream effectors of many, but not all, signalling events of the NO/cGMP and the ANP/cGMP pathways. cGKI relaxes smooth muscle tone and prevents platelet aggregation, whereas cGKII inhibits renin secretion, chloride/water secretion in the small intestine, the resetting of the clock during early night, and endochondral bone growth. This chapter focuses on the involvement of cGKs in cardiovascular and non-cardiovascular processes including cell growth and metabolism.
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Affiliation(s)
- Franz Hofmann
- FOR 923, Institut für Pharmakologie und Toxikologie, der Technischen Universität München, Munich, Germany
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21
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Lutz SZ, Hennige AM, Feil S, Peter A, Gerling A, Machann J, Kröber SM, Rath M, Schürmann A, Weigert C, Häring HU, Feil R. Genetic ablation of cGMP-dependent protein kinase type I causes liver inflammation and fasting hyperglycemia. Diabetes 2011; 60:1566-76. [PMID: 21464444 PMCID: PMC3292332 DOI: 10.2337/db10-0760] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE The nitric oxide/cGMP/cGMP-dependent protein kinase type I (cGKI) signaling pathway regulates cell functions that play a pivotal role in the pathogenesis of type 2 diabetes. However, the impact of a dysfunction of this pathway for glucose metabolism in vivo is unknown. RESEARCH DESIGN AND METHODS The expression of cGKI in tissues relevant to insulin action was analyzed by immunohistochemistry. The metabolic consequences of a genetic deletion of cGKI were studied in mice that express cGKI selectively in smooth muscle but not in other cell types (cGKI-SM mice). RESULTS In wild-type mice, cGKI protein was detected in hepatic stellate cells, but not in hepatocytes, skeletal muscle, fat cells, or pancreatic β-cells. Compared with control animals, cGKI-SM mice had higher energy expenditure in the light phase associated with lower body weight and fat mass and increased insulin sensitivity. Mutant mice also showed higher fasting glucose levels, whereas insulin levels and intraperitoneal glucose tolerance test results were similar to those in control animals. Interleukin (IL)-6 signaling was strongly activated in the liver of cGKI-SM mice as demonstrated by increased levels of IL-6, phospho-signal transducer and activator of transcription 3 (Tyr 705), suppressor of cytokine signaling-3, and serum amyloid A2. Insulin-stimulated tyrosine phosphorylation of the insulin receptor in the liver was impaired in cGKI-SM mice. The fraction of Mac-2–positive macrophages in the liver was significantly higher in cGKI-SM mice than in control mice. In contrast with cGKI-SM mice, conditional knockout mice lacking cGKI only in the nervous system were normal with respect to body weight, energy expenditure, fasting glucose, IL-6, and insulin action in the liver. CONCLUSIONS Genetic deletion of cGKI in non-neuronal cells results in a complex metabolic phenotype, including liver inflammation and fasting hyperglycemia. Loss of cGKI in hepatic stellate cells may affect liver metabolism via a paracrine mechanism that involves enhanced macrophage infiltration and IL-6 signaling.
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Affiliation(s)
- Stefan Z Lutz
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, University of Tübingen, Tübingen, Germany
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