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Brands J, Bravo S, Jürgenliemke L, Grätz L, Schihada H, Frechen F, Alenfelder J, Pfeil C, Ohse PG, Hiratsuka S, Kawakami K, Schmacke LC, Heycke N, Inoue A, König G, Pfeifer A, Wachten D, Schulte G, Steinmetzer T, Watts VJ, Gomeza J, Simon K, Kostenis E. A molecular mechanism to diversify Ca 2+ signaling downstream of Gs protein-coupled receptors. Nat Commun 2024; 15:7684. [PMID: 39227390 PMCID: PMC11372221 DOI: 10.1038/s41467-024-51991-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 08/20/2024] [Indexed: 09/05/2024] Open
Abstract
A long-held tenet in inositol-lipid signaling is that cleavage of membrane phosphoinositides by phospholipase Cβ (PLCβ) isozymes to increase cytosolic Ca2+ in living cells is exclusive to Gq- and Gi-sensitive G protein-coupled receptors (GPCRs). Here we extend this central tenet and show that Gs-GPCRs also partake in inositol-lipid signaling and thereby increase cytosolic Ca2+. By combining CRISPR/Cas9 genome editing to delete Gαs, the adenylyl cyclase isoforms 3 and 6, or the PLCβ1-4 isozymes, with pharmacological and genetic inhibition of Gq and G11, we pin down Gs-derived Gβγ as driver of a PLCβ2/3-mediated cytosolic Ca2+ release module. This module does not require but crosstalks with Gαs-dependent cAMP, demands Gαq to release PLCβ3 autoinhibition, but becomes Gq-independent with mutational disruption of the PLCβ3 autoinhibited state. Our findings uncover the key steps of a previously unappreciated mechanism utilized by mammalian cells to finetune their calcium signaling regulation through Gs-GPCRs.
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Affiliation(s)
- Julian Brands
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
- Research Training Group 1873, University of Bonn, Bonn, Germany
| | - Sergi Bravo
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Lars Jürgenliemke
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
- Research Training Group 2873, University of Bonn, Bonn, Germany
| | - Lukas Grätz
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Hannes Schihada
- Department of Pharmaceutical Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Fabian Frechen
- Institute of Innate Immunity, Medical Faculty, University of Bonn, Bonn, Germany
| | - Judith Alenfelder
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Cy Pfeil
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
- Research Training Group 1873, University of Bonn, Bonn, Germany
- Amsterdam Institute for Molecular and Life Sciences (AIMMS), Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Paul Georg Ohse
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Suzune Hiratsuka
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Kouki Kawakami
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, 153-8505, Japan
| | - Luna C Schmacke
- Department of Pharmaceutical Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Nina Heycke
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Gabriele König
- Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Alexander Pfeifer
- Institute of Pharmacology and Toxicology, University Hospital, University of Bonn, Bonn, Germany
| | - Dagmar Wachten
- Institute of Innate Immunity, Medical Faculty, University of Bonn, Bonn, Germany
| | - Gunnar Schulte
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Torsten Steinmetzer
- Department of Pharmaceutical Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue Institute of Drug Discovery, Purdue University, West Lafayette, IN, USA
| | - Jesús Gomeza
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Katharina Simon
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131, Padova, Italy
| | - Evi Kostenis
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany.
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Boileve A, Romito O, Hof T, Levallois A, Brard L, d'Hers S, Fouchet A, Simard C, Guinamard R, Brette F, Sallé L. EPAC1 and 2 inhibit K + currents via PLC/PKC and NOS/PKG pathways in rat ventricular cardiomyocytes. Am J Physiol Cell Physiol 2024; 327:C557-C570. [PMID: 38985989 DOI: 10.1152/ajpcell.00582.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 05/29/2024] [Accepted: 06/19/2024] [Indexed: 07/12/2024]
Abstract
The exchange protein directly activated by cAMP (EPAC) has been implicated in cardiac proarrhythmic signaling pathways including spontaneous diastolic Ca2+ leak from sarcoplasmic reticulum and increased action potential duration (APD) in isolated ventricular cardiomyocytes. The action potential (AP) lengthening following acute EPAC activation is mainly due to a decrease of repolarizing steady-state K+ current (IKSS) but the mechanisms involved remain unknown. This study aimed to assess the role of EPAC1 and EPAC2 in the decrease of IKSS and to investigate the underlying signaling pathways. AP and K+ currents were recorded with the whole cell configuration of the patch-clamp technique in freshly isolated rat ventricular myocytes. EPAC1 and EPAC2 were pharmacologically activated with 8-(4-chlorophenylthio)-2'-O-methyl-cAMP acetoxymethyl ester (8-CPTAM, 10 µmol/L) and inhibited with R-Ce3F4 and ESI-05, respectively. Inhibition of EPAC1 and EPAC2 significantly decreased the effect of 8-CPTAM on APD and IKSS showing that both EPAC isoforms are involved in these effects. Unexpectedly, calmodulin-dependent protein kinase II (CaMKII) inhibition by AIP or KN-93, and Ca2+ chelation by intracellular BAPTA, did not impact the response to 8-CPTAM. However, inhibition of PLC/PKC and nitric oxide synthase (NOS)/PKG pathways partially prevents the 8-CPTAM-dependent decrease of IKSS. Finally, the cumulative inhibition of PKC and PKG blocked the 8-CPTAM effect, suggesting that these two actors work along parallel pathways to regulate IKSS upon EPAC activation. On the basis of such findings, we propose that EPAC1 and EPAC2 are involved in APD lengthening by inhibiting a K+ current via both PLC/PKC and NOS/PKG pathways. This may have pathological implications since EPAC is upregulated in diseases such as cardiac hypertrophy.NEW & NOTEWORHTY Exchange protein directly activated by cAMP (EPAC) proteins modulate ventricular electrophysiology at the cellular level. Both EPAC1 and EPAC2 isoforms participate in this effect. Mechanistically, PLC/PKC and nitric oxide synthase (NO)/PKG pathways are involved in regulating K+ repolarizing current whereas the well-known downstream effector of EPAC, calmodulin-dependent protein kinase II (CaMKII), does not participate. This may have pathological implications since EPAC is upregulated in diseases such as cardiac hypertrophy. Thus, EPAC inhibition may be a new approach to prevent arrhythmias under pathological conditions.
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Affiliation(s)
- Arthur Boileve
- UR 4650 PSIR, GIP Cyceron, Caen, France
- Normandie University, Caen, France
- UNICAEN, Caen, France
| | - Olivier Romito
- UR 4650 PSIR, GIP Cyceron, Caen, France
- Normandie University, Caen, France
- UNICAEN, Caen, France
| | - Thomas Hof
- UR 4650 PSIR, GIP Cyceron, Caen, France
- Normandie University, Caen, France
- UNICAEN, Caen, France
| | - Aurélia Levallois
- UR 4650 PSIR, GIP Cyceron, Caen, France
- Normandie University, Caen, France
- UNICAEN, Caen, France
| | - Laura Brard
- UR 4650 PSIR, GIP Cyceron, Caen, France
- Normandie University, Caen, France
- UNICAEN, Caen, France
| | - Sarah d'Hers
- UR 4650 PSIR, GIP Cyceron, Caen, France
- Normandie University, Caen, France
- UNICAEN, Caen, France
| | - Alexandre Fouchet
- UR 4650 PSIR, GIP Cyceron, Caen, France
- Normandie University, Caen, France
- UNICAEN, Caen, France
| | - Christophe Simard
- UR 4650 PSIR, GIP Cyceron, Caen, France
- Normandie University, Caen, France
- UNICAEN, Caen, France
| | - Romain Guinamard
- UR 4650 PSIR, GIP Cyceron, Caen, France
- Normandie University, Caen, France
- UNICAEN, Caen, France
| | - Fabien Brette
- PhyMedExp, INSERM U1046, CNRS 9412, Université de Montpellier, Montpellier, France
| | - Laurent Sallé
- UR 4650 PSIR, GIP Cyceron, Caen, France
- Normandie University, Caen, France
- UNICAEN, Caen, France
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Wei W, Smrcka AV. Internalized β2-Adrenergic Receptors Oppose PLC-Dependent Hypertrophic Signaling. Circ Res 2024; 135:e24-e38. [PMID: 38813686 PMCID: PMC11223973 DOI: 10.1161/circresaha.123.323201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 05/16/2024] [Indexed: 05/31/2024]
Abstract
BACKGROUND Chronically elevated neurohumoral drive, and particularly elevated adrenergic tone leading to β-adrenergic receptor (β-AR) overstimulation in cardiac myocytes, is a key mechanism involved in the progression of heart failure. β1-AR (β1-adrenergic receptor) and β2-ARs (β2-adrenergic receptor) are the 2 major subtypes of β-ARs present in the human heart; however, they elicit different or even opposite effects on cardiac function and hypertrophy. For example, chronic activation of β1-ARs drives detrimental cardiac remodeling while β2-AR signaling is protective. The underlying molecular mechanisms for cardiac protection through β2-ARs remain unclear. METHODS β2-AR signaling mechanisms were studied in isolated neonatal rat ventricular myocytes and adult mouse ventricular myocytes using live cell imaging and Western blotting methods. Isolated myocytes and mice were used to examine the roles of β2-AR signaling mechanisms in the regulation of cardiac hypertrophy. RESULTS Here, we show that β2-AR activation protects against hypertrophy through inhibition of phospholipaseCε signaling at the Golgi apparatus. The mechanism for β2-AR-mediated phospholipase C inhibition requires internalization of β2-AR, activation of Gi and Gβγ subunit signaling at endosome and ERK (extracellular regulated kinase) activation. This pathway inhibits both angiotensin II and Golgi-β1-AR-mediated stimulation of phosphoinositide hydrolysis at the Golgi apparatus ultimately resulting in decreased PKD (protein kinase D) and histone deacetylase 5 phosphorylation and protection against cardiac hypertrophy. CONCLUSIONS This reveals a mechanism for β2-AR antagonism of the phospholipase Cε pathway that may contribute to the known protective effects of β2-AR signaling on the development of heart failure.
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Affiliation(s)
- Wenhui Wei
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Alan V. Smrcka
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, United States
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Roy S, Roy S, Halder S, Jana K, Ukil A. Leishmania exploits host cAMP/EPAC/calcineurin signaling to induce an IL-33-mediated anti-inflammatory environment for the establishment of infection. J Biol Chem 2024; 300:107366. [PMID: 38750790 PMCID: PMC11208913 DOI: 10.1016/j.jbc.2024.107366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 05/03/2024] [Accepted: 05/05/2024] [Indexed: 06/10/2024] Open
Abstract
Host anti-inflammatory responses are critical for the progression of visceral leishmaniasis, and the pleiotropic cytokine interleukin (IL)-33 was found to be upregulated in infection. Here, we documented that IL-33 induction is a consequence of elevated cAMP-mediated exchange protein activated by cAMP (EPAC)/calcineurin-dependent signaling and essential for the sustenance of infection. Leishmania donovani-infected macrophages showed upregulation of IL-33 and its neutralization resulted in decreased parasite survival and increased inflammatory responses. Infection-induced cAMP was involved in IL-33 production and of its downstream effectors PKA and EPAC, only the latter was responsible for elevated IL-33 level. EPAC initiated Rap-dependent phospholipase C activation, which triggered the release of intracellular calcium followed by calcium/calmodulin complex formation. Screening of calmodulin-dependent enzymes affirmed involvement of the phosphatase calcineurin in cAMP/EPAC/calcium/calmodulin signaling-induced IL-33 production and parasite survival. Activated calcineurin ensured nuclear localization of the transcription factors, nuclear factor of activated T cell 1 and hypoxia-inducible factor 1 alpha required for IL-33 transcription, and we further confirmed this by chromatin immunoprecipitation assay. Administering specific inhibitors of nuclear factor of activated T cell 1 and hypoxia-inducible factor 1 alpha in BALB/c mouse model of visceral leishmaniasis decreased liver and spleen parasite burden along with reduction in IL-33 level. Splenocyte supernatants of inhibitor-treated infected mice further documented an increase in tumor necrosis factor alpha and IL-12 level with simultaneous decrease of IL-10, thereby indicating an overall disease-escalating effect of IL-33. Thus, this study demonstrates that cAMP/EPAC/calcineurin signaling is crucial for the activation of IL-33 and in effect creates anti-inflammatory responses, essential for infection.
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Affiliation(s)
- Souravi Roy
- Department of Biochemistry, University of Calcutta, Kolkata, India
| | - Shalini Roy
- Department of Biochemistry, University of Calcutta, Kolkata, India
| | - Satyajit Halder
- Division of Molecular Medicine, Bose Institute, Kolkata, India
| | - Kuladip Jana
- Division of Molecular Medicine, Bose Institute, Kolkata, India
| | - Anindita Ukil
- Department of Biochemistry, University of Calcutta, Kolkata, India.
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Pizzoni A, Zhang X, Altschuler DL. From membrane to nucleus: A three-wave hypothesis of cAMP signaling. J Biol Chem 2024; 300:105497. [PMID: 38016514 PMCID: PMC10788541 DOI: 10.1016/j.jbc.2023.105497] [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: 09/18/2023] [Revised: 11/14/2023] [Accepted: 11/19/2023] [Indexed: 11/30/2023] Open
Abstract
For many decades, our understanding of G protein-coupled receptor (GPCR) activity and cyclic AMP (cAMP) signaling was limited exclusively to the plasma membrane. However, a growing body of evidence has challenged this view by introducing the concept of endocytosis-dependent GPCR signaling. This emerging paradigm emphasizes not only the sustained production of cAMP but also its precise subcellular localization, thus transforming our understanding of the spatiotemporal organization of this process. Starting from this alternative point of view, our recent work sheds light on the role of an endocytosis-dependent calcium release from the endoplasmic reticulum in the control of nuclear cAMP levels. This is achieved through the activation of local soluble adenylyl cyclase, which in turn regulates the activation of local protein kinase A (PKA) and downstream transcriptional events. In this review, we explore the dynamic evolution of research on cyclic AMP signaling, including the findings that led us to formulate the novel three-wave hypothesis. We delve into how we abandoned the paradigm of cAMP generation limited to the plasma membrane and the changing perspectives on the rate-limiting step in nuclear PKA activation.
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Affiliation(s)
- Alejandro Pizzoni
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Xuefeng Zhang
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Daniel L Altschuler
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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Mastos C, Xu X, Keen AC, Halls ML. Signalling of Adrenoceptors: Canonical Pathways and New Paradigms. Handb Exp Pharmacol 2024; 285:147-184. [PMID: 38227198 DOI: 10.1007/164_2023_704] [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: 01/17/2024]
Abstract
The concept of G protein-coupled receptors initially arose from studies of the β-adrenoceptor, adenylyl cyclase, and cAMP signalling pathway. Since then both canonical G protein-coupled receptor signalling pathways and emerging paradigms in receptor signalling have been defined by experiments focused on adrenoceptors. Here, we discuss the evidence for G protein coupling specificity of the nine adrenoceptor subtypes. We summarise the ability of each of the adrenoceptors to activate proximal signalling mediators including cAMP, calcium, mitogen-activated protein kinases, and protein kinase C pathways. Finally, we highlight the importance of precise spatial and temporal control of adrenoceptor signalling that is controlled by the localisation of receptors at intracellular membranes and in larger protein complexes.
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Affiliation(s)
- Chantel Mastos
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Xiaomeng Xu
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Alastair C Keen
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Michelle L Halls
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia.
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Ferri G, Fernández LR, Di Mario G, Musikant D, Palermo JA, Edreira MM. Host cell cAMP-Epac-Rap1b pathway inhibition by hawthorn extract as a potential target against Trypanosoma cruzi infection. Front Microbiol 2023; 14:1301862. [PMID: 38156015 PMCID: PMC10754523 DOI: 10.3389/fmicb.2023.1301862] [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: 09/25/2023] [Accepted: 11/16/2023] [Indexed: 12/30/2023] Open
Abstract
Although the two drugs currently available for the treatment of Chagas disease, Benznidazole and Nifurtimox, have proven to be effective in the acute phase of the disease, the 60-90-day treatment leads to high toxicity and unwanted side effects, presenting, in addition, a low efficacy in the chronic phase of the disease. For this reason, new therapies that are more effective are needed. In this regard, we have recently shown that the inhibition of the Epac-Rap1b pathway suppressed the cAMP-mediated host cell invasion by Trypanosoma cruzi. Interestingly, it has been described that vitexin, a natural flavone that protects against ischemia-reperfusion damage, acts by inhibiting the expression of Epac and Rap1 proteins. Vitexin can be found in plants of the genus Crataegus spp., traditionally known as hawthorn, which are of great interest considering their highly documented use as cardio-protectors. Pre-treating cells with an extract of Crataegus oxyacantha produced levels of T. cruzi invasion comparable to the ones observed for the commercially available Epac1-specific inhibitor, ESI-09. In addition, extract-treated cells exhibited a decrease in the activation of Rap1b, suggesting that the effects of the extract would be mediated by the inhibition of the cAMP-Epac-Rap1 signaling pathway. Using HPLC-HRMS2, we could confirm the presence of vitexin, and other flavones that could act as inhibitors of Epac/Rap1b, in the extracts of C. oxyacantha. Most significantly, when cells were treated with the extract of C. oxyacantha in conjunction with Nifurtimox, an increased modulation of invasion was observed.
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Affiliation(s)
- Gabriel Ferri
- CONICET-Universidad de Buenos Aires, IQUIBICEN, Ciudad de Buenos Aires, Argentina
- Laboratorio de Biología Molecular de Trypanosomas, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos, Ciudad de Buenos Aires, Argentina
| | - Lucía R. Fernández
- Laboratorio de Biología Molecular de Trypanosomas, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos, Ciudad de Buenos Aires, Argentina
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Unidad de Microanálisis y Métodos Físicos Aplicados a la Química Orgánica (UMYMFOR), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Guillermo Di Mario
- CONICET-Universidad de Buenos Aires, IQUIBICEN, Ciudad de Buenos Aires, Argentina
- Laboratorio de Biología Molecular de Trypanosomas, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos, Ciudad de Buenos Aires, Argentina
| | - Daniel Musikant
- CONICET-Universidad de Buenos Aires, IQUIBICEN, Ciudad de Buenos Aires, Argentina
- Laboratorio de Biología Molecular de Trypanosomas, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos, Ciudad de Buenos Aires, Argentina
| | - Jorge A. Palermo
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Unidad de Microanálisis y Métodos Físicos Aplicados a la Química Orgánica (UMYMFOR), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Martin M. Edreira
- CONICET-Universidad de Buenos Aires, IQUIBICEN, Ciudad de Buenos Aires, Argentina
- Laboratorio de Biología Molecular de Trypanosomas, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos, Ciudad de Buenos Aires, Argentina
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
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Gárriz A, Morokuma J, Toribio D, Zoukhri D. Role of the adenylate cyclase/cyclic AMP pathway in oxytocin-induced lacrimal gland myoepithelial cells contraction. Exp Eye Res 2023; 233:109526. [PMID: 37290630 PMCID: PMC10527592 DOI: 10.1016/j.exer.2023.109526] [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: 11/15/2022] [Revised: 05/03/2023] [Accepted: 06/06/2023] [Indexed: 06/10/2023]
Abstract
The aim of these studies was to investigate the involvement of the second messenger 3',5'-cyclic adenosine monophosphate (cAMP) and its downstream effectors in oxytocin (OXT)-mediated lacrimal gland myoepithelial cell (MEC) contraction. Lacrimal gland MEC were isolated and propagated from alpha-smooth muscle actin (SMA)-GFP mice. RNA and protein samples were prepared to analyze G protein expression by RT-PCR and western blotting; respectively. Changes in intracellular cAMP concentration were measured using a competitive ELISA kit. To increase intracellular cAMP concentration, the following agents were used: forskolin (FKN, a direct activator of adenylate cyclase), 3-isobutyl-1-methylxanthine (IBMX, an inhibitor of the phosphodiesterase that hydrolyzes cAMP), or a cell permeant cAMP analog, dibutyryl (db)-cAMP. In addition, inhibitors and selective agonists were used to investigate the role of cAMP effector molecules, protein kinase A (PKA) and exchange protein activated by cAMP (EPAC) in OXT-induced MEC contraction. MEC contraction was monitored in real time and changes in cell size were quantified using ImageJ software. The adenylate cyclase coupling G proteins, Gαs, Gαo, and Gαi, are expressed in lacrimal gland MEC at both the mRNA and protein levels. OXT increased intracellular cAMP in a concentration-dependent manner. FKN, IBMX and db-cAMP significantly stimulated MEC contraction. Preincubation of cells with either Myr-PKI, a specific PKA inhibitor or ESI09, an EPAC inhibitor, resulted in almost complete inhibition of both FKN- as well as OXT-stimulated MEC contraction. Finally, direct activation of PKA or EPAC using selective agonists triggered MEC contraction. We conclude that cAMP agonists modulate lacrimal gland MEC contraction via PKA and EPAC activation which also play a major role in OXT induced MEC contraction.
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Affiliation(s)
- Angela Gárriz
- Department of Comprehensive Care, Tufts University School of Dental Medicine, Boston, MA, USA
| | - Junji Morokuma
- Department of Comprehensive Care, Tufts University School of Dental Medicine, Boston, MA, USA
| | - Danny Toribio
- Department of Comprehensive Care, Tufts University School of Dental Medicine, Boston, MA, USA
| | - Driss Zoukhri
- Department of Comprehensive Care, Tufts University School of Dental Medicine, Boston, MA, USA; Department of Ophthalmology, Tufts University School of Medicine, Boston, MA, USA.
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9
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Liu XJ, Pang H, Long YQ, Wang JQ, Niu Y, Zhang RG. Pro-inflammatory action of formoterol in human bronchial epithelia. Mol Immunol 2023; 160:95-102. [PMID: 37413911 DOI: 10.1016/j.molimm.2023.06.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/19/2023] [Accepted: 06/26/2023] [Indexed: 07/08/2023]
Abstract
Despite the wide usage of β2-adrenoceptor agonists in asthma treatment, they do have side effects such as aggravating inflammation. We previously reported that isoprenaline induced Cl- secretion and IL-6 release via cAMP-dependent pathways in human bronchial epithelia, but the mechanisms underlying the inflammation-aggravation effects of β2-adrenoceptor agonists remain pooly understood. In this study, we investigated formoterol, a more specific β2-adrenoceptor agonist, -mediated signaling pathways involved in the production of IL-6 and IL-8 in 16HBE14o- human bronchial epithelia. The effects of formoterol were detected in the presence of PKA, exchange protein directly activated by cAMP (EPAC), cystic fibrosis transmembrane conductance regulator (CFTR), extracellular signal-regulated protein kinase (ERK)1/2 and Src inhibitors. The involvement of β-arrestin2 was determined using siRNA knockdown. Our results indicate that formoterol can induce IL-6 and IL-8 secretion in concentration-dependent manner. The PKA-specific inhibitor, H89, partially inhibited IL-6 release, but not IL-8. Another intracellular cAMP receptor, EPAC, was not involved in either IL-6 or IL-8 release. PD98059 and U0126, two ERK1/2 inhibitors, blocked IL-8 while attenuated IL-6 secretion induced by formoterol. Furthermore, formoterol-induced IL-6 and IL-8 release was attenuated by Src inhibitors, namely dasatinib and PP1, and CFTRinh172, a CFTR inhibitor. In addition, knockdown of β-arrestin2 by siRNA only suppressed IL-8 release when a high concentration of formoterol (1 μM) was used. Taken together, our results suggest that formoterol stimulates IL-6 and IL-8 release which involves PKA/Src/ERK1/2 and/or β-arrestin2 signaling pathways.
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Affiliation(s)
- Xing-Jian Liu
- Department of Physiology, Basic Medical School, Guangdong Medical University, Zhanjiang, China
| | - Hao Pang
- First Clinical School, Guangdong Medical University, Zhanjiang, China
| | - Yu-Qian Long
- First Clinical School, Guangdong Medical University, Zhanjiang, China
| | - Ji-Qing Wang
- First Clinical School, Guangdong Medical University, Zhanjiang, China
| | - Ya Niu
- School of Biomedical Sciences, The Chinese University of Hong Kong, New Territories, Hong Kong, China
| | - Rui-Gang Zhang
- Department of Physiology, Basic Medical School, Guangdong Medical University, Zhanjiang, China.
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10
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Wei W, Smrcka AV. Internalized β2-Adrenergic Receptors Inhibit Subcellular Phospholipase C-Dependent Cardiac Hypertrophic Signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544153. [PMID: 37333278 PMCID: PMC10274790 DOI: 10.1101/2023.06.07.544153] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Chronically elevated neurohumoral drive, and particularly elevated adrenergic tone leading to β-adrenergic receptor (β-AR) overstimulation in cardiac myocytes, is a key mechanism involved in the progression of heart failure. β1-AR and β2-ARs are the two major subtypes of β-ARs present in the human heart, however, they elicit different or even opposite effects on cardiac function and hypertrophy. For example, chronic activation of β1ARs drives detrimental cardiac remodeling while β2AR signaling is protective. The underlying molecular mechanisms for cardiac protection through β2ARs remain unclear. Here we show that β2-AR protects against hypertrophy through inhibition of PLCε signaling at the Golgi apparatus. The mechanism for β2AR-mediated PLC inhibition requires internalization of β2AR, activation of Gi and Gβγ subunit signaling at endosomes and ERK activation. This pathway inhibits both angiotensin II and Golgi-β1-AR-mediated stimulation of phosphoinositide hydrolysis at the Golgi apparatus ultimately resulting in decreased PKD and HDAC5 phosphorylation and protection against cardiac hypertrophy. This reveals a mechanism for β2-AR antagonism of the PLCε pathway that may contribute to the known protective effects of β2-AR signaling on the development of heart failure.
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Affiliation(s)
- Wenhui Wei
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Alan V. Smrcka
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, United States
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11
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Chaoul V, Hanna R, Hachem P, El Hayek MS, Nour‐Eldine W, Abou‐Khalil P, Abi‐Ramia E, Vandecasteele G, Abi‐Gerges A. Differential changes in cyclic adenosine 3′‐5′ monophosphate (
cAMP
) effectors and major Ca
2+
handling proteins during diabetic cardiomyopathy. J Cell Mol Med 2023; 27:1277-1289. [PMID: 36967707 PMCID: PMC10148055 DOI: 10.1111/jcmm.17733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/23/2023] [Accepted: 03/14/2023] [Indexed: 03/29/2023] Open
Abstract
Diabetic cardiomyopathy (DCM) is associated with differential and time-specific regulation of β-adrenergic receptors and cardiac cyclic nucleotide phosphodiesterases with consequences for total cyclic adenosine 3'-5' monophosphate (cAMP) levels. We aimed to investigate whether these changes are associated with downstream impairments in cAMP and Ca2+ signalling in a type 1 diabetes (T1D)-induced DCM model. T1D was induced in adult male rats by streptozotocin (65 mg/kg) injection. DCM was assessed by cardiac structural and molecular remodelling. We delineated sequential changes affecting the exchange protein (Epac1/2), cAMP-dependent protein kinase A (PKA) and Ca2+ /Calmodulin-dependent kinase II (CaMKII) at 4, 8 and 12 weeks following diabetes, by real-time quantitative PCR and western blot. Expression of Ca2+ ATPase pump (SERCA2a), phospholamban (PLB) and Troponin I (TnI) was also examined. Early upregulation of Epac1 transcripts was noted in diabetic hearts at Week 4, followed by increases in Epac2 mRNA, but not protein levels, at Week 12. Expression of PKA subunits (RI, RIIα and Cα) remained unchanged regardless of the disease stage, whereas CaMKII increased at Week 12 in DCM. Moreover, PLB transcripts were upregulated in diabetic hearts, whereas SERCA2a and TnI gene expression was unchanged irrespective of the disease evolution. PLB phosphorylation at threonine-17 was increased in DCM, whereas phosphorylation of both PLB at serine-16 and TnI at serine-23/24 was unchanged. We show for the first time differential and time-specific regulations in cardiac cAMP effectors and Ca2+ handling proteins, data that may prove useful in proposing new therapeutic approaches in T1D-induced DCM.
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Affiliation(s)
- Victoria Chaoul
- Gilbert and Rose‐Marie Chagoury School of MedicineLebanese American UniversityP.O. Box 36ByblosLebanon
| | - Rita Hanna
- Gilbert and Rose‐Marie Chagoury School of MedicineLebanese American UniversityP.O. Box 36ByblosLebanon
| | - Pia Hachem
- Gilbert and Rose‐Marie Chagoury School of MedicineLebanese American UniversityP.O. Box 36ByblosLebanon
| | - Magali Samia El Hayek
- Signaling and Cardiovascular Pathophysiology, UMR‐S1180Université Paris‐SaclayOrsay91400France
| | - Wared Nour‐Eldine
- Gilbert and Rose‐Marie Chagoury School of MedicineLebanese American UniversityP.O. Box 36ByblosLebanon
| | - Pamela Abou‐Khalil
- Gilbert and Rose‐Marie Chagoury School of MedicineLebanese American UniversityP.O. Box 36ByblosLebanon
| | - Elias Abi‐Ramia
- School of Arts and Sciences, Department of Natural SciencesLebanese American UniversityByblosLebanon
| | - Grégoire Vandecasteele
- Signaling and Cardiovascular Pathophysiology, UMR‐S1180Université Paris‐SaclayOrsay91400France
| | - Aniella Abi‐Gerges
- Gilbert and Rose‐Marie Chagoury School of MedicineLebanese American UniversityP.O. Box 36ByblosLebanon
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12
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Morales A, Mohan R, Chen X, Coffman BL, Bendahmane M, Watch L, West JL, Bakshi S, Traynor JR, Giovannucci DR, Kammermeier PJ, Axelrod D, Currie KP, Smrcka AV, Anantharam A. PACAP and acetylcholine cause distinct Ca2+ signals and secretory responses in chromaffin cells. J Gen Physiol 2023; 155:e202213180. [PMID: 36538657 PMCID: PMC9770323 DOI: 10.1085/jgp.202213180] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 09/22/2022] [Accepted: 11/18/2022] [Indexed: 12/24/2022] Open
Abstract
The adrenomedullary chromaffin cell transduces chemical messages into outputs that regulate end organ function throughout the periphery. At least two important neurotransmitters are released by innervating preganglionic neurons to stimulate exocytosis in the chromaffin cell-acetylcholine (ACh) and pituitary adenylate cyclase activating polypeptide (PACAP). Although PACAP is widely acknowledged as an important secretagogue in this system, the pathway coupling PACAP stimulation to chromaffin cell secretion is poorly understood. The goal of this study is to address this knowledge gap. Here, it is shown that PACAP activates a Gαs-coupled pathway that must signal through phospholipase C ε (PLCε) to drive Ca2+ entry and exocytosis. PACAP stimulation causes a complex pattern of Ca2+ signals in chromaffin cells, leading to a sustained secretory response that is kinetically distinct from the form stimulated by ACh. Exocytosis caused by PACAP is associated with slower release of peptide cargo than exocytosis stimulated by ACh. Importantly, only the secretory response to PACAP, not ACh, is eliminated in cells lacking PLCε expression. The data show that ACh and PACAP, acting through distinct signaling pathways, enable nuanced and variable secretory outputs from chromaffin cells.
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Affiliation(s)
- Alina Morales
- Department of Neurosciences, University of Toledo, Toledo, OH, USA
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Ramkumar Mohan
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Xiaohuan Chen
- Department of Neurosciences, University of Toledo, Toledo, OH, USA
| | | | | | - Lester Watch
- Department of Obstetrics and Gynecology, Duke University School of Medicine, Durham, NC, USA
| | - Joshua L. West
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Shreeya Bakshi
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - John R. Traynor
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | | | - Paul J. Kammermeier
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA
| | - Daniel Axelrod
- Department of Physics and LSA Biophysics, University of Michigan, Ann Arbor, MI, USA
| | - Kevin P.M. Currie
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ, USA
| | - Alan V. Smrcka
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Arun Anantharam
- Department of Neurosciences, University of Toledo, Toledo, OH, USA
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13
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Sakanoue W, Yokoyama T, Hirakawa M, Maesawa S, Sato K, Saino T. 3-Iodothyronamine, a trace amine-associated receptor agonist, regulates intracellular Ca2+ increases via CaMK II through Epac2 in rat cerebral arterioles. Biomed Res 2023; 44:219-232. [PMID: 37779034 DOI: 10.2220/biomedres.44.219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Trace amines (TAs) in the nervous system bind to TA-associated receptors (TAARs) and are involved in the regulation of monoaminergic functions. Among TAAR subtypes, TAAR1 has been implicated in the development of neurological disorders, such as schizophrenia. The present study investigated the effects of the TAAR1 agonist, 3-iodothyronamine (T1AM) on cerebral arterioles using fluctuations in the intracellular concentration of Ca2+ ([Ca2+]i) as an index of contractile responses. In cerebral arterioles, most of the TAAR agonists did not increase [Ca2+]i, while only T1AM elevated [Ca2+]i in vascular smooth muscle cells. This increase involved extracellular Ca2+ influx through T-type Ca2+ channels and inositol trisphosphate- and ryanodine-receptor-mediated Ca2+ release from intracellular stores. The inhibition of the cAMP sensor, exchange protein directly activated by cAMP (Epac) 2, and calmodulin kinase (CaMK) II strongly inhibited Ca2+ elevations. The present study revealed that T1AM acted not only on the TAAR1 receptor as previously suggested, but also on other G-protein coupled receptors and/or signal transduction systems to increase intracellular Ca2+ in cerebral arteriole smooth muscle cells. These results suggest that when using T1AM in clinical practice, attention should be paid to the early rise in blood pressure.
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Affiliation(s)
- Wakana Sakanoue
- Division of Dental Anesthesiology, Department of Reconstructive Oral and Maxillofacial Surgery, School of Dentistry, Iwate Medical University, Yahaba, Japan
| | - Takuya Yokoyama
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Masato Hirakawa
- Department of Anatomy (Cell Biology), Iwate Medical University, Yahaba, Japan
| | - Satsuki Maesawa
- Division of Dental Anesthesiology, Department of Reconstructive Oral and Maxillofacial Surgery, School of Dentistry, Iwate Medical University, Yahaba, Japan
| | - Kenichi Sato
- Division of Dental Anesthesiology, Department of Reconstructive Oral and Maxillofacial Surgery, School of Dentistry, Iwate Medical University, Yahaba, Japan
| | - Tomoyuki Saino
- Department of Anatomy (Cell Biology), Iwate Medical University, Yahaba, Japan
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14
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Functional Insights into Protein Kinase A (PKA) Signaling from C. elegans. LIFE (BASEL, SWITZERLAND) 2022; 12:life12111878. [PMID: 36431013 PMCID: PMC9692727 DOI: 10.3390/life12111878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/04/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022]
Abstract
Protein kinase A (PKA), which regulates a diverse set of biological functions downstream of cyclic AMP (cAMP), is a tetramer consisting of two catalytic subunits (PKA-C) and two regulatory subunits (PKA-R). When cAMP binds the PKA-R subunits, the PKA-C subunits are released and interact with downstream effectors. In Caenorhabditis elegans (C. elegans), PKA-C and PKA-R are encoded by kin-1 and kin-2, respectively. This review focuses on the contributions of work in C. elegans to our understanding of the many roles of PKA, including contractility and oocyte maturation in the reproductive system, lipid metabolism, physiology, mitochondrial function and lifespan, and a wide variety of behaviors. C. elegans provides a powerful genetic platform for understanding how this kinase can regulate an astounding variety of physiological responses.
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15
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Ni Z, Cheng X. Origin and Isoform Specific Functions of Exchange Proteins Directly Activated by cAMP: A Phylogenetic Analysis. Cells 2021; 10:cells10102750. [PMID: 34685730 PMCID: PMC8534922 DOI: 10.3390/cells10102750] [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: 09/24/2021] [Revised: 10/09/2021] [Accepted: 10/09/2021] [Indexed: 12/21/2022] Open
Abstract
Exchange proteins directly activated by cAMP (EPAC1 and EPAC2) are one of the several families of cellular effectors of the prototypical second messenger cAMP. To understand the origin and molecular evolution of EPAC proteins, we performed a comprehensive phylogenetic analysis of EPAC1 and EPAC2. Our study demonstrates that unlike its cousin PKA, EPAC proteins are only present in multicellular Metazoa. Within the EPAC family, EPAC1 is only associated with chordates, while EPAC2 spans the entire animal kingdom. Despite a much more contemporary origin, EPAC1 proteins show much more sequence diversity among species, suggesting that EPAC1 has undergone more selection and evolved faster than EPAC2. Phylogenetic analyses of the individual cAMP binding domain (CBD) and guanine nucleotide exchange (GEF) domain of EPACs, two most conserved regions between the two isoforms, further reveal that EPAC1 and EPAC2 are closely clustered together within both the larger cyclic nucleotide receptor and RAPGEF families. These results support the notion that EPAC1 and EPAC2 share a common ancestor resulting from a fusion between the CBD of PKA and the GEF from RAPGEF1. On the other hand, the two terminal extremities and the RAS-association (RA) domains show the most sequence diversity between the two isoforms. Sequence diversities within these regions contribute significantly to the isoform-specific functions of EPACs. Importantly, unique isoform-specific sequence motifs within the RA domain have been identified.
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Affiliation(s)
- Zhuofu Ni
- Department of Integrative Biology & Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA;
| | - Xiaodong Cheng
- Department of Integrative Biology & Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA;
- Texas Therapeutics Institute, Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Correspondence: ; Tel.: +1-713-500-7487
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16
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On the Mechanism of Cardioprotective Effect of Fabomotizole in Alcoholic Cardiomyopathy. Bull Exp Biol Med 2021; 171:41-44. [PMID: 34050832 DOI: 10.1007/s10517-021-05168-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Indexed: 10/21/2022]
Abstract
The molecular mechanisms underlying the cardioprotective effect of fabomotizole were studied using the translational rat model of alcoholic cardiomyopathy developed by us. It was shown that intraperitoneal administration of fabomotizole (15 mg/kg) for 28 days to animals with alcoholic cardiomyopathy contributes to normalization of the expression of mRNA of genes of regulatory proteins СаМ (p=0.00001), Ерас1 (p=0.021), and Ерас2 (p=0.018) and receptors RyR2 (p=0.0031) and IP3R2 (p=0.006) in the myocardium of the myocardium of the left ventricle that is enhanced in control animals (p<0.05). These changes were accompanied by echocardiographically documented decrease in the degree of left ventricle remodeling and improvement of its inotropic function.
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17
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Kozhevnikova LM, Barchukov VV, Semenova NP, Vititnova MB, Kryzhanovskii SA. Studies of Molecular Mechanisms Underlying Cardioprotective Action of the ALM-802 Compound. Bull Exp Biol Med 2021; 170:312-315. [PMID: 33452980 DOI: 10.1007/s10517-021-05058-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Indexed: 10/22/2022]
Abstract
The mechanisms underlying cardioprotective activity of compound ALM-802 were studied in experiments on rats with chronic post-infarction heart failure. Real-time PCR showed that compound ALM-802 (daily intraperitoneal injections in a dose of 2 mg/kg for 28 days starting from day 91 after myocardial infarction modeling) restored the expression of genes encoding β1- (p=0.00001) and β2-adrenoreceptors (p=0.01) and type 2 ryanodine receptors (p=0.008) in the myocardium that was reduced in control animals. These effects can serve as the basis for the ability of the compound to reduce the intensity of remodeling and increase the inotropic function of the left heart ventricle shown earlier in this model.
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Affiliation(s)
- L M Kozhevnikova
- V. V. Zakusov Research Institute of Pharmacology, Moscow, Russia.,Research Institute of General Pathology and Pathophysiology, Moscow, Russia
| | - V V Barchukov
- V. V. Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - N P Semenova
- Research Institute of General Pathology and Pathophysiology, Moscow, Russia
| | - M B Vititnova
- V. V. Zakusov Research Institute of Pharmacology, Moscow, Russia.
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18
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Muralidharan K, Van Camp MM, Lyon AM. Structure and regulation of phospholipase Cβ and ε at the membrane. Chem Phys Lipids 2021; 235:105050. [PMID: 33422547 DOI: 10.1016/j.chemphyslip.2021.105050] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/28/2020] [Accepted: 01/04/2021] [Indexed: 12/28/2022]
Abstract
Phospholipase C (PLC) β and ε enzymes hydrolyze phosphatidylinositol (PI) lipids in response to direct interactions with heterotrimeric G protein subunits and small GTPases, which are activated downstream of G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs). PI hydrolysis generates second messengers that increase the intracellular Ca2+ concentration and activate protein kinase C (PKC), thereby regulating numerous physiological processes. PLCβ and PLCε share a highly conserved core required for lipase activity, but use different strategies and structural elements to autoinhibit basal activity, bind membranes, and engage G protein activators. In this review, we discuss recent structural insights into these enzymes and the implications for how they engage membranes alone or in complex with their G protein regulators.
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Affiliation(s)
- Kaushik Muralidharan
- Department of Biological Sciences, 560 Oval Drive, Purdue University, West Lafayette, IN, 47907, United States.
| | - Michelle M Van Camp
- Department of Chemistry, 560 Oval Drive, Purdue University, West Lafayette, IN, 47907, United States.
| | - Angeline M Lyon
- Department of Biological Sciences, 560 Oval Drive, Purdue University, West Lafayette, IN, 47907, United States; Department of Chemistry, 560 Oval Drive, Purdue University, West Lafayette, IN, 47907, United States.
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19
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Sieng M, Selvia AF, Garland-Kuntz EE, Hopkins JB, Fisher IJ, Marti AT, Lyon AM. Functional and structural characterization of allosteric activation of phospholipase Cε by Rap1A. J Biol Chem 2020; 295:16562-16571. [PMID: 32948655 PMCID: PMC7864056 DOI: 10.1074/jbc.ra120.015685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/08/2020] [Indexed: 01/16/2023] Open
Abstract
Phospholipase Cε (PLCε) is activated downstream of G protein-coupled receptors and receptor tyrosine kinases through direct interactions with small GTPases, including Rap1A and Ras. Although Ras has been reported to allosterically activate the lipase, it is not known whether Rap1A has the same ability or what its molecular mechanism might be. Rap1A activates PLCε in response to the stimulation of β-adrenergic receptors, translocating the complex to the perinuclear membrane. Because the C-terminal Ras association (RA2) domain of PLCε was proposed to the primary binding site for Rap1A, we first confirmed using purified proteins that the RA2 domain is indeed essential for activation by Rap1A. However, we also showed that the PLCε pleckstrin homology (PH) domain and first two EF hands (EF1/2) are required for Rap1A activation and identified hydrophobic residues on the surface of the RA2 domain that are also necessary. Small-angle X-ray scattering showed that Rap1A binding induces and stabilizes discrete conformational states in PLCε variants that can be activated by the GTPase. These data, together with the recent structure of a catalytically active fragment of PLCε, provide the first evidence that Rap1A, and by extension Ras, allosterically activate the lipase by promoting and stabilizing interactions between the RA2 domain and the PLCε core.
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Affiliation(s)
- Monita Sieng
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Arielle F Selvia
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | | | - Jesse B Hopkins
- Biophysics Collaborative Access Team, Illinois Institute of Technology, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois, USA
| | - Isaac J Fisher
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Andrea T Marti
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Angeline M Lyon
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA; Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA.
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20
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Robichaux WG, Mei FC, Yang W, Wang H, Sun H, Zhou Z, Milewicz DM, Teng BB, Cheng X. Epac1 (Exchange Protein Directly Activated by cAMP 1) Upregulates LOX-1 (Oxidized Low-Density Lipoprotein Receptor 1) to Promote Foam Cell Formation and Atherosclerosis Development. Arterioscler Thromb Vasc Biol 2020; 40:e322-e335. [PMID: 33054390 DOI: 10.1161/atvbaha.119.314238] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE The cAMP second messenger system, a major stress-response pathway, plays essential roles in normal cardiovascular functions and in pathogenesis of heart diseases. Here, we test the hypothesis that the Epac1 (exchange protein directly activated by cAMP 1) acts as a major downstream effector of cAMP signaling to promote atherogenesis and represents a novel therapeutic target. Approach and Results: To ascertain Epac1's function in atherosclerosis development, a triple knockout mouse model (LTe) was generated by crossing Epac1-/- mice with atherosclerosis-prone LDb mice lacking both Ldlr and Apobec1. Deletion of Epac1 led to a significant reduction of atherosclerotic lesion formation as measured by postmortem staining, accompanied by attenuated macrophage/foam cell infiltrations within atherosclerotic plaques as determined by immunofluorescence staining in LTe animals compared with LDb littermates. Primary bone marrow-derived macrophages were isolated from Epac1-null and wild-type mice to investigate the role of Epac1 in lipid uptake and foam cell formation. ox-LDLs (oxidized low-density lipoproteins) stimulation of bone marrow-derived macrophages led to elevated intracellular cAMP and Epac1 levels, whereas an Epac-specific agonist, increased lipid accumulation in wild-type, but not Epac1-null, bone marrow-derived macrophages. Mechanistically, Epac1 acts through PKC (protein kinase C) to upregulate LOX-1 (ox-LDL receptor 1), a major scavenger receptor for ox-LDL uptake, exerting a feedforward mechanism with ox-LDL to increase lipid uptake and propel foam cell formation and atherogenesis. CONCLUSIONS Our study demonstrates a fundamental role of cAMP/Epac1 signaling in vascular remodeling by promoting ox-LDL uptake and foam cell formation during atherosclerosis lesion development. Therefore, Epac1 represents a promising, unexplored therapeutic target for atherosclerosis.
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Affiliation(s)
- William G Robichaux
- Department of Integrative Biology and Pharmacology (W.G.R., F.C.M., W.Y., H.W., X.C.), McGovern Medical School, The University of Texas Health Science Center, Houston.,Texas Therapeutics Institute (W.G.R., F.C.M., W.Y., H.W., X.C.), McGovern Medical School, The University of Texas Health Science Center, Houston.,Brown Foundation Institute of Molecular Medicine (W.G.R., F.C.M., W.Y., H.W., H.S., B.-B.T.), McGovern Medical School, The University of Texas Health Science Center, Houston
| | - Fang C Mei
- Department of Integrative Biology and Pharmacology (W.G.R., F.C.M., W.Y., H.W., X.C.), McGovern Medical School, The University of Texas Health Science Center, Houston.,Texas Therapeutics Institute (W.G.R., F.C.M., W.Y., H.W., X.C.), McGovern Medical School, The University of Texas Health Science Center, Houston.,Brown Foundation Institute of Molecular Medicine (W.G.R., F.C.M., W.Y., H.W., H.S., B.-B.T.), McGovern Medical School, The University of Texas Health Science Center, Houston
| | - Wenli Yang
- Department of Integrative Biology and Pharmacology (W.G.R., F.C.M., W.Y., H.W., X.C.), McGovern Medical School, The University of Texas Health Science Center, Houston.,Texas Therapeutics Institute (W.G.R., F.C.M., W.Y., H.W., X.C.), McGovern Medical School, The University of Texas Health Science Center, Houston.,Brown Foundation Institute of Molecular Medicine (W.G.R., F.C.M., W.Y., H.W., H.S., B.-B.T.), McGovern Medical School, The University of Texas Health Science Center, Houston
| | - Hui Wang
- Department of Integrative Biology and Pharmacology (W.G.R., F.C.M., W.Y., H.W., X.C.), McGovern Medical School, The University of Texas Health Science Center, Houston.,Texas Therapeutics Institute (W.G.R., F.C.M., W.Y., H.W., X.C.), McGovern Medical School, The University of Texas Health Science Center, Houston.,Brown Foundation Institute of Molecular Medicine (W.G.R., F.C.M., W.Y., H.W., H.S., B.-B.T.), McGovern Medical School, The University of Texas Health Science Center, Houston
| | - Hua Sun
- Brown Foundation Institute of Molecular Medicine (W.G.R., F.C.M., W.Y., H.W., H.S., B.-B.T.), McGovern Medical School, The University of Texas Health Science Center, Houston
| | - Zhen Zhou
- Division of Medical Genetics, Department of Internal Medicine (Z.Z., D.M.M.), McGovern Medical School, The University of Texas Health Science Center, Houston
| | - Dianna M Milewicz
- Division of Medical Genetics, Department of Internal Medicine (Z.Z., D.M.M.), McGovern Medical School, The University of Texas Health Science Center, Houston
| | - Ba-Bie Teng
- Brown Foundation Institute of Molecular Medicine (W.G.R., F.C.M., W.Y., H.W., H.S., B.-B.T.), McGovern Medical School, The University of Texas Health Science Center, Houston
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology (W.G.R., F.C.M., W.Y., H.W., X.C.), McGovern Medical School, The University of Texas Health Science Center, Houston.,Texas Therapeutics Institute (W.G.R., F.C.M., W.Y., H.W., X.C.), McGovern Medical School, The University of Texas Health Science Center, Houston
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21
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Formoso K, Lezoualc'h F, Mialet-Perez J. Role of EPAC1 Signalosomes in Cell Fate: Friends or Foes? Cells 2020; 9:E1954. [PMID: 32854274 PMCID: PMC7563956 DOI: 10.3390/cells9091954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/21/2020] [Accepted: 08/22/2020] [Indexed: 02/06/2023] Open
Abstract
The compartmentation of signaling processes is accomplished by the assembly of protein complexes called signalosomes. These signaling platforms colocalize enzymes, substrates, and anchoring proteins into specific subcellular compartments. Exchange protein directly activated by cAMP 1 (EPAC1) is an effector of the second messenger, 3',5'-cyclic adenosine monophosphate (cAMP) that is associated with multiple roles in several pathologies including cardiac diseases. Both EPAC1 intracellular localization and molecular partners are key players in the regulation of cell fate, which may have important therapeutic potential. In this review, we summarize the recent findings on EPAC1 structure, regulation, and pharmacology. We describe the importance of EPAC1 subcellular distribution in its biological action, paying special attention to its nuclear localization and mechanism of action leading to cardiomyocyte hypertrophy. In addition, we discuss the role of mitochondrial EPAC1 in the regulation of cell death. Depending on the cell type and stress condition, we present evidence that supports either a protective or detrimental role of EPAC1 activation.
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Affiliation(s)
- Karina Formoso
- INSERM UMR-1048, Institute of Metabolic and Cardiovascular Diseases, and Université de Toulouse III-Paul Sabatier, 31432 Toulouse, France
| | - Frank Lezoualc'h
- INSERM UMR-1048, Institute of Metabolic and Cardiovascular Diseases, and Université de Toulouse III-Paul Sabatier, 31432 Toulouse, France
| | - Jeanne Mialet-Perez
- INSERM UMR-1048, Institute of Metabolic and Cardiovascular Diseases, and Université de Toulouse III-Paul Sabatier, 31432 Toulouse, France
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22
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Rugema NY, Garland-Kuntz EE, Sieng M, Muralidharan K, Van Camp MM, O'Neill H, Mbongo W, Selvia AF, Marti AT, Everly A, McKenzie E, Lyon AM. Structure of phospholipase Cε reveals an integrated RA1 domain and previously unidentified regulatory elements. Commun Biol 2020; 3:445. [PMID: 32796910 PMCID: PMC7427993 DOI: 10.1038/s42003-020-01178-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/27/2020] [Indexed: 12/15/2022] Open
Abstract
Phospholipase Cε (PLCε) generates lipid-derived second messengers at the plasma and perinuclear membranes in the cardiovascular system. It is activated in response to a wide variety of signals, such as those conveyed by Rap1A and Ras, through a mechanism that involves its C-terminal Ras association (RA) domains (RA1 and RA2). However, the complexity and size of PLCε has hindered its structural and functional analysis. Herein, we report the 2.7 Å crystal structure of the minimal fragment of PLCε that retains basal activity. This structure includes the RA1 domain, which forms extensive interactions with other core domains. A conserved amphipathic helix in the autoregulatory X-Y linker of PLCε is also revealed, which we show modulates activity in vitro and in cells. The studies provide the structural framework for the core of this critical cardiovascular enzyme that will allow for a better understanding of its regulation and roles in disease.
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Affiliation(s)
- Ngango Y Rugema
- Department of Chemistry, Purdue University, West Lafayette, 47907, IN, USA
| | | | - Monita Sieng
- Department of Chemistry, Purdue University, West Lafayette, 47907, IN, USA
| | - Kaushik Muralidharan
- Department of Biological Sciences, Purdue University, West Lafayette, 47907, IN, USA
| | | | - Hannah O'Neill
- Department of Chemistry, Purdue University, West Lafayette, 47907, IN, USA
| | - William Mbongo
- Department of Chemistry, Purdue University, West Lafayette, 47907, IN, USA
| | - Arielle F Selvia
- Department of Chemistry, Purdue University, West Lafayette, 47907, IN, USA
| | - Andrea T Marti
- Department of Biological Sciences, Purdue University, West Lafayette, 47907, IN, USA
| | - Amanda Everly
- Department of Chemistry, Purdue University, West Lafayette, 47907, IN, USA
| | - Emmanda McKenzie
- Department of Chemistry, Purdue University, West Lafayette, 47907, IN, USA
| | - Angeline M Lyon
- Department of Chemistry, Purdue University, West Lafayette, 47907, IN, USA.
- Department of Biological Sciences, Purdue University, West Lafayette, 47907, IN, USA.
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23
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Castaneda PG, Cecchetelli AD, Pettit HN, Cram EJ. Gα/GSA-1 works upstream of PKA/KIN-1 to regulate calcium signaling and contractility in the Caenorhabditis elegans spermatheca. PLoS Genet 2020; 16:e1008644. [PMID: 32776941 PMCID: PMC7444582 DOI: 10.1371/journal.pgen.1008644] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 08/20/2020] [Accepted: 06/29/2020] [Indexed: 11/18/2022] Open
Abstract
Correct regulation of cell contractility is critical for the function of many biological systems. The reproductive system of the hermaphroditic nematode C. elegans contains a contractile tube of myoepithelial cells known as the spermatheca, which stores sperm and is the site of oocyte fertilization. Regulated contraction of the spermatheca pushes the embryo into the uterus. Cell contractility in the spermatheca is dependent on actin and myosin and is regulated, in part, by Ca2+ signaling through the phospholipase PLC-1, which mediates Ca2+ release from the endoplasmic reticulum. Here, we describe a novel role for GSA-1/Gαs, and protein kinase A, composed of the catalytic subunit KIN-1/PKA-C and the regulatory subunit KIN-2/PKA-R, in the regulation of Ca2+ release and contractility in the C. elegans spermatheca. Without GSA-1/Gαs or KIN-1/PKA-C, Ca2+ is not released, and oocytes become trapped in the spermatheca. Conversely, when PKA is activated through either a gain of function allele in GSA-1 (GSA-1(GF)) or by depletion of KIN-2/PKA-R, the transit times and total numbers, although not frequencies, of Ca2+ pulses are increased, and Ca2+ propagates across the spermatheca even in the absence of oocyte entry. In the spermathecal-uterine valve, loss of GSA-1/Gαs or KIN-1/PKA-C results in sustained, high levels of Ca2+ and a loss of coordination between the spermathecal bag and sp-ut valve. Additionally, we show that depleting phosphodiesterase PDE-6 levels alters contractility and Ca2+ dynamics in the spermatheca, and that the GPB-1 and GPB-2 Gβ subunits play a central role in regulating spermathecal contractility and Ca2+ signaling. This work identifies a signaling network in which Ca2+ and cAMP pathways work together to coordinate spermathecal contractions for successful ovulations.
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Affiliation(s)
- Perla G. Castaneda
- Department of Biology, Northeastern University, Boston, MA, United States
| | | | - Hannah N. Pettit
- Department of Biology, Northeastern University, Boston, MA, United States
| | - Erin J. Cram
- Department of Biology, Northeastern University, Boston, MA, United States
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24
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Integration of Rap1 and Calcium Signaling. Int J Mol Sci 2020; 21:ijms21051616. [PMID: 32120817 PMCID: PMC7084553 DOI: 10.3390/ijms21051616] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 02/24/2020] [Accepted: 02/25/2020] [Indexed: 02/07/2023] Open
Abstract
Ca2+ is a universal intracellular signal. The modulation of cytoplasmic Ca2+ concentration regulates a plethora of cellular processes, such as: synaptic plasticity, neuronal survival, chemotaxis of immune cells, platelet aggregation, vasodilation, and cardiac excitation–contraction coupling. Rap1 GTPases are ubiquitously expressed binary switches that alternate between active and inactive states and are regulated by diverse families of guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Active Rap1 couples extracellular stimulation with intracellular signaling through secondary messengers—cyclic adenosine monophosphate (cAMP), Ca2+, and diacylglycerol (DAG). Much evidence indicates that Rap1 signaling intersects with Ca2+ signaling pathways to control the important cellular functions of platelet activation or neuronal plasticity. Rap1 acts as an effector of Ca2+ signaling when activated by mechanisms involving Ca2+ and DAG-activated (CalDAG-) GEFs. Conversely, activated by other GEFs, such as cAMP-dependent GEF Epac, Rap1 controls cytoplasmic Ca2+ levels. It does so by regulating the activity of Ca2+ signaling proteins such as sarcoendoplasmic reticulum Ca2+-ATPase (SERCA). In this review, we focus on the physiological significance of the links between Rap1 and Ca2+ signaling and emphasize the molecular interactions that may offer new targets for the therapy of Alzheimer’s disease, hypertension, and atherosclerosis, among other diseases.
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25
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Silva I, Magalhães-Cardoso MT, Ferreirinha F, Moreira S, Costa AF, Silva D, Vieira C, Silva-Ramos M, Correia-de-Sá P. β 3 Adrenoceptor-induced cholinergic inhibition in human and rat urinary bladders involves the exchange protein directly activated by cyclic AMP 1 favoring adenosine release. Br J Pharmacol 2020; 177:1589-1608. [PMID: 31721163 DOI: 10.1111/bph.14921] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 10/11/2019] [Accepted: 10/21/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND PURPOSE The mechanism by which β3 receptor agonists (e.g. mirabegron) control bladder overactivity may involve adenosine release from human and rat detrusor smooth muscle. Retrograde activation of adenosine A1 receptors reduces ACh release from cholinergic bladder nerves. β3 -Adrenoceptors usually couple to adenylyl cyclase. Here we investigated, which of the cAMP targets, protein kinase A or the exchange protein directly activated by cAMP (EPAC) could be involved in this cholinergic inhibition of the bladder. EXPERIMENTAL APPROACH [3 H]ACh and adenosine release from urothelium-denuded detrusor strips of cadaveric human organ donors and rats were measured by liquid scintillation spectrometry and HPLC, respectively. In vivo cystometry was also performed in urethane-anaesthetized rats. KEY RESULTS The exchange protein directly activated by cAMP (EPAC) inhibitor, ESI-09, prevented mirabegron- and isoprenaline-induced adenosine release from human and rat detrusor strips respectively. ESI-09, but not the PKA inhibitor, H-89, attenuated inhibition of [3 H]ACh release from stimulated (10 Hz) detrusor strips caused by activating β3 -adrenoceptors, AC (forskolin) and EPAC1 (8-CTP-2Me-cAMP). Isoprenaline-induced inhibition of [3 H]ACh release was also prevented by inhibitors of PKC (chelerythrine and Go6976) and of the equilibrative nucleoside transporter 1 (ENT1; dipyridamole and NBTI), but not by PLC inhibition with U73122. Pretreatment with ESI-09, but not with H-89, prevented the reduction of the voiding frequency caused by isoprenaline and forskolin in vivo. CONCLUSION AND IMPLICATIONS Data suggest that β3 -adrenoceptor-induced inhibition of cholinergic neurotransmission in human and rat urinary bladders involves activation of an EPAC1/PKC pathway downstream cAMP production resulting in adenosine outflow via ENT1.
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Affiliation(s)
- Isabel Silva
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - M Teresa Magalhães-Cardoso
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Fátima Ferreirinha
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Sílvia Moreira
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Ana Filipa Costa
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Diogo Silva
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Cátia Vieira
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Miguel Silva-Ramos
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Serviço de Urologia, Centro Hospitalar Universitário do Porto (CHUP), Porto, Portugal
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
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26
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Kaur S, Jones T, Ward M, Kang N, Ruygrok P. 170 Subcellular Distribution of Epac 2 in Relation to Key Excitation-Contraction Coupling Proteins in Human Atrial Tissue. Heart Lung Circ 2020. [DOI: 10.1016/j.hlc.2020.09.177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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27
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Matthews HR, Tan SRX, Shoesmith JA, Ahmad S, Valli H, Jeevaratnam K, Huang CLH. Sodium current inhibition following stimulation of exchange protein directly activated by cyclic-3',5'-adenosine monophosphate (Epac) in murine skeletal muscle. Sci Rep 2019; 9:1927. [PMID: 30760734 PMCID: PMC6374420 DOI: 10.1038/s41598-018-36386-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 11/15/2018] [Indexed: 02/07/2023] Open
Abstract
We investigated effects of pharmacological triggering of exchange protein directly activated by cyclic-3',5'-adenosine monophosphate (Epac) on Nav1.4 currents from intact murine (C67BL6) skeletal muscle fibres for the first time. This employed a loose patch clamp technique which examined ionic currents in response to superimposed 10-ms V1 steps to varying degrees of depolarisation, followed by V2 steps to a fixed, +100 mV depolarisation relative to resting membrane potential following 40 mV hyperpolarising prepulses of 50 ms duration. The activation and inactivation properties of the resulting Na+ membrane current densities revealed reduced maximum currents and steepnesses in their voltage dependences after addition of the Epac activator 8-(4-chlorophenylthio)adenosine-3',5'-cyclic monophosphate (1 µM) to the bathing Krebs-Henseleit solutions. Contrastingly, voltages at half-maximal current and timecourses of currents obtained in response to the V1 depolarising steps were unchanged. These effects were abolished by further addition of the RyR-inhibitor dantrolene (10 µM). In contrast, challenge by dantrolene alone left both currents and their parameters intact. These effects of Epac activation in inhibiting skeletal muscle, Nav1.4, currents, complement similar effects previously reported in the homologous Nav1.5 in murine cardiomyocytes. They are discussed in terms of a hypothesis implicating Epac actions in increasing RyR-mediated SR Ca2+ release resulting in a Ca2+-mediated inhibition of Nav1.4. The latter effect may form the basis for Ca2+-dependent Na+ channel dysregulation in SCN4A channelopathies associated with cold- and K+-aggravated myotonias.
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Affiliation(s)
- Hugh R Matthews
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom
| | - Sapphire R X Tan
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom
| | - Jonathan A Shoesmith
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom
| | - Shiraz Ahmad
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom
| | - Haseeb Valli
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, GU2 7AL, Guildford, Surrey, United Kingdom
| | - Christopher L-H Huang
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom.
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, United Kingdom.
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28
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Jeevaratnam K, Salvage SC, Li M, Huang CLH. Regulatory actions of 3',5'-cyclic adenosine monophosphate on osteoclast function: possible roles of Epac-mediated signaling. Ann N Y Acad Sci 2018; 1433:18-28. [PMID: 29846007 DOI: 10.1111/nyas.13861] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 04/20/2018] [Accepted: 04/26/2018] [Indexed: 02/02/2023]
Abstract
Alterations in cellular levels of the second messenger 3',5'-cyclic adenosine monophosphate ([cAMP]i ) regulate a wide range of physiologically important cellular signaling processes in numerous cell types. Osteoclasts are terminally differentiated, multinucleated cells specialized for bone resorption. Their systemic regulator, calcitonin, triggers morphometrically and pharmacologically distinct retraction (R) and quiescence (Q) effects on cell-spread area and protrusion-retraction motility, respectively, paralleling its inhibition of bone resorption. Q effects were reproduced by cholera toxin-mediated Gs -protein activation known to increase [cAMP]i , unaccompanied by the [Ca2+ ]i changes contrastingly associated with R effects. We explore a hypothesis implicating cAMP signaling involving guanine nucleotide-exchange activation of the small GTPase Ras-proximate-1 (Rap1) by exchange proteins directly activated by cAMP (Epac). Rap1 activates integrin clustering, cell adhesion to bone matrix, associated cytoskeletal modifications and signaling processes, and transmembrane transduction functions. Epac activation enhanced, whereas Epac inhibition or shRNA-mediated knockdown compromised, the appearance of markers for osteoclast differentiation and motility following stimulation by receptor activator of nuclear factor kappa-Β ligand (RANKL). Deficiencies in talin and Rap1 compromised in vivo bone resorption, producing osteopetrotic phenotypes in genetically modified murine models. Translational implications of an Epac-Rap1 signaling hypothesis in relationship to N-bisphosphonate actions on prenylation and membrane localization of small GTPases are discussed.
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Affiliation(s)
- Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK.,School of Medicine, Perdana University - Royal College of Surgeons Ireland, Selangor, Malaysia
| | - Samantha C Salvage
- Department of Biochemistry, University of Cambridge, Cambridge, UK.,Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Mengye Li
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Christopher L-H Huang
- Department of Biochemistry, University of Cambridge, Cambridge, UK.,Physiological Laboratory, University of Cambridge, Cambridge, UK
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29
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Garland-Kuntz EE, Vago FS, Sieng M, Van Camp M, Chakravarthy S, Blaine A, Corpstein C, Jiang W, Lyon AM. Direct observation of conformational dynamics of the PH domain in phospholipases Cϵ and β may contribute to subfamily-specific roles in regulation. J Biol Chem 2018; 293:17477-17490. [PMID: 30242131 PMCID: PMC6231117 DOI: 10.1074/jbc.ra118.003656] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 09/17/2018] [Indexed: 12/19/2022] Open
Abstract
Phospholipase C (PLC) enzymes produce second messengers that increase the intracellular Ca2+ concentration and activate protein kinase C (PKC). These enzymes also share a highly conserved arrangement of core domains. However, the contributions of the individual domains to regulation are poorly understood, particularly in isoforms lacking high-resolution information, such as PLCϵ. Here, we used small-angle X-ray scattering (SAXS), EM, and functional assays to gain insights into the molecular architecture of PLCϵ, revealing that its PH domain is conformationally dynamic and essential for activity. We further demonstrate that the PH domain of PLCβ exhibits similar dynamics in solution that are substantially different from its conformation observed in multiple previously reported crystal structures. We propose that this conformational heterogeneity contributes to subfamily-specific differences in activity and regulation by extracellular signals.
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Affiliation(s)
| | - Frank S Vago
- Biological Sciences, Purdue University, West Lafayette, Indiana 47907 and
| | | | | | - Srinivas Chakravarthy
- the Biophysics Collaborative Access Team, Illinois Institute of Technology, Sector 18ID, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439
| | | | | | - Wen Jiang
- Biological Sciences, Purdue University, West Lafayette, Indiana 47907 and
| | - Angeline M Lyon
- From the Departments of Chemistry and
- Biological Sciences, Purdue University, West Lafayette, Indiana 47907 and
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30
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Ulloa-Aguirre A, Reiter E, Crépieux P. FSH Receptor Signaling: Complexity of Interactions and Signal Diversity. Endocrinology 2018; 159:3020-3035. [PMID: 29982321 DOI: 10.1210/en.2018-00452] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 06/27/2018] [Indexed: 12/20/2022]
Abstract
FSH is synthesized in the pituitary by gonadotrope cells. By binding to and interacting with its cognate receptor [FSH receptor (FSHR)] in the gonads, this gonadotropin plays a key role in the control of gonadal function and reproduction. Upon activation, the FSHR undergoes conformational changes leading to transduction of intracellular signals, including dissociation of G protein complexes into components and activation of several associated interacting partners, which concertedly regulate downstream effectors. The canonical Gs/cAMP/protein kinase A pathway, considered for a long time as the sole effector of FSHR-mediated signaling, is now viewed as one of several mechanisms employed by this receptor to transduce intracellular signals in response to the FSH stimulus. This complex network of signaling pathways allows for a fine-tuning regulation of the gonadotropic stimulus, where activation/inhibition of its multiple components vary depending on the cell context, cell developmental stage, and concentration of associated receptors and corresponding ligands. Activation of these multiple signaling modules eventually converge to the hormone-integrated biological response, including survival, proliferation and differentiation of target cells, synthesis and secretion of paracrine/autocrine regulators, and, at the molecular level, functional selectivity and differential gene expression. In this mini-review, we discuss the complexity of FSHR-mediated intracellular signals activated in response to ligand stimulation. A better understanding of the signaling pathways involved in FSH action might potentially influence the development of new therapeutic strategies for reproductive disorders.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación, Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Eric Reiter
- Biology and Bioinformatics of Signaling Systems Group, Unité Mixtes de Recherche 85, Unité Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, Nouzilly, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7247, Nouzilly, France
- Université François Rabelais, Nouzilly, France
| | - Pascale Crépieux
- Biology and Bioinformatics of Signaling Systems Group, Unité Mixtes de Recherche 85, Unité Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, Nouzilly, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7247, Nouzilly, France
- Université François Rabelais, Nouzilly, France
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31
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Robichaux WG, Cheng X. Intracellular cAMP Sensor EPAC: Physiology, Pathophysiology, and Therapeutics Development. Physiol Rev 2018; 98:919-1053. [PMID: 29537337 PMCID: PMC6050347 DOI: 10.1152/physrev.00025.2017] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 12/13/2022] Open
Abstract
This review focuses on one family of the known cAMP receptors, the exchange proteins directly activated by cAMP (EPACs), also known as the cAMP-regulated guanine nucleotide exchange factors (cAMP-GEFs). Although EPAC proteins are fairly new additions to the growing list of cAMP effectors, and relatively "young" in the cAMP discovery timeline, the significance of an EPAC presence in different cell systems is extraordinary. The study of EPACs has considerably expanded the diversity and adaptive nature of cAMP signaling associated with numerous physiological and pathophysiological responses. This review comprehensively covers EPAC protein functions at the molecular, cellular, physiological, and pathophysiological levels; and in turn, the applications of employing EPAC-based biosensors as detection tools for dissecting cAMP signaling and the implications for targeting EPAC proteins for therapeutic development are also discussed.
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Affiliation(s)
- William G Robichaux
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center , Houston, Texas
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center , Houston, Texas
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32
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Laudette M, Zuo H, Lezoualc'h F, Schmidt M. Epac Function and cAMP Scaffolds in the Heart and Lung. J Cardiovasc Dev Dis 2018; 5:jcdd5010009. [PMID: 29401660 PMCID: PMC5872357 DOI: 10.3390/jcdd5010009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 01/25/2018] [Accepted: 01/29/2018] [Indexed: 12/13/2022] Open
Abstract
Evidence collected over the last ten years indicates that Epac and cAMP scaffold proteins play a critical role in integrating and transducing multiple signaling pathways at the basis of cardiac and lung physiopathology. Some of the deleterious effects of Epac, such as cardiomyocyte hypertrophy and arrhythmia, initially described in vitro, have been confirmed in genetically modified mice for Epac1 and Epac2. Similar recent findings have been collected in the lung. The following sections will describe how Epac and cAMP signalosomes in different subcellular compartments may contribute to cardiac and lung diseases.
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Affiliation(s)
- Marion Laudette
- Inserm UMR-1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université Toulouse III, 31432 Toulouse, France.
| | - Haoxiao Zuo
- Department of Molecular Pharmacology, University of Groningen, 9713AV Groningen, The Netherlands.
- Groningen Research Institute for Asthma and COPD (GRIAC), University Medical Center Groningen, University of Groningen, 9713AV Groningen, The Netherlands.
| | - Frank Lezoualc'h
- Inserm UMR-1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université Toulouse III, 31432 Toulouse, France.
| | - Martina Schmidt
- Department of Molecular Pharmacology, University of Groningen, 9713AV Groningen, The Netherlands.
- Groningen Research Institute for Asthma and COPD (GRIAC), University Medical Center Groningen, University of Groningen, 9713AV Groningen, The Netherlands.
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33
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Leroy J, Vandecasteele G, Fischmeister R. Cyclic AMP signaling in cardiac myocytes. CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2017.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Nussinov R, Tsai CJ, Jang H. Is Nanoclustering essential for all oncogenic KRas pathways? Can it explain why wild-type KRas can inhibit its oncogenic variant? Semin Cancer Biol 2018; 54:114-120. [PMID: 29307569 DOI: 10.1016/j.semcancer.2018.01.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/19/2017] [Accepted: 01/04/2018] [Indexed: 10/18/2022]
Abstract
Membrane-anchored oncogenic KRas can dimerize, form nanoclusters, and signal through the MAPK (Raf/MEK/ERK) and PI3Kα/Akt/mTOR. Both pathways are needed in KRAS-driven proliferation. Here we ask: Is oncogenic KRas nanoclustering (or dimerization) essential for all KRas signaling pathways? Raf kinase domain dimerization, thus MAPK activation, requires KRas nanoclusters. By contrast, the PI3Kα heterodimer acts as a monomeric unit; thus, does PI3Kα activation and PI3Kα/Akt/mTOR signaling require nanoclustering? Further, calmodulin binds only to oncogenic KRas4B. Here we ask: Does calmodulin downregulate KRas4B cancer development as suggested early on, or promote it? We also ask: Why is oncogenic KRas4B the most abundant isoform? Does wild-type Ras indeed inhibit its oncogenic variants as data appeared to suggest? And related to the last question, why is wild-type KRas a more potent inhibitor of its oncogenic form than wild-type NRas of its oncogenic form? Resolving these cardinal questions, and others, such as how exactly does RASSF5 (NORE1A) act as tumor suppressor, and why Ras isoforms tend to occur in distinct cancer types are crucial for effective pharmacology. In this review, we take a nanoclustering/dimerization-centric outlook and show that many questions can be explained by simply considering Ras nanoclustering.
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Affiliation(s)
- Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Chung-Jung Tsai
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
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35
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Li M, Hothi SS, Salvage SC, Jeevaratnam K, Grace AA, Huang CLH. Arrhythmic effects of Epac-mediated ryanodine receptor activation in Langendorff-perfused murine hearts are associated with reduced conduction velocity. Clin Exp Pharmacol Physiol 2018; 44:686-692. [PMID: 28316073 PMCID: PMC5488224 DOI: 10.1111/1440-1681.12751] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/05/2017] [Accepted: 03/07/2017] [Indexed: 12/19/2022]
Abstract
Recent papers have attributed arrhythmic substrate in murine RyR2‐P2328S hearts to reduced action potential (AP) conduction velocities (CV), reflecting acute functional inhibition and/or reduced expression of sodium channels. We explored for acute effects of direct exchange protein directly activated by cAMP (Epac)‐mediated ryanodine receptor‐2 (RyR2) activation on arrhythmic substrate and CV. Monophasic action potential (MAP) recordings demonstrated that initial steady (8 Hz) extrinsic pacing elicited ventricular tachycardia (VT) in 0 of 18 Langendorff‐perfused wild‐type mouse ventricles before pharmacological intervention. The Epac activator 8‐CPT (8‐(4‐chlorophenylthio)‐2′‐O‐methyladenosine‐3′,5′‐cyclic monophosphate) (VT in 1 of 7 hearts), and the RyR2 blocker dantrolene, either alone (0 of 11) or with 8‐CPT (0 of 9) did not then increase VT incidence (P>.05). Both progressively increased pacing rates and programmed extrasystolic (S2) stimuli similarly produced no VT in untreated hearts (n=20 and n=9 respectively). 8‐CPT challenge then increased VT incidences (5 of 7 and 4 of 8 hearts respectively; P<.05). However, dantrolene, whether alone (0 of 10 and 1 of 13) or combined with 8‐CPT (0 of 10 and 0 of 13) did not increase VT incidence relative to those observed in untreated hearts (P>.05). 8‐CPT but not dantrolene, whether alone or combined with 8‐CPT, correspondingly increased AP latencies (1.14±0.04 (n=7), 1.04±0.03 (n=10), 1.09±0.05 (n=8) relative to respective control values). In contrast, AP durations, conditions for 2:1 conduction block and ventricular effective refractory periods remained unchanged throughout. We thus demonstrate for the first time that acute RyR2 activation reversibly induces VT in specific association with reduced CV.
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Affiliation(s)
- Mengye Li
- Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Sandeep S Hothi
- Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Samantha C Salvage
- Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom.,Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, VSM Building, University of Surrey, Guildford, United Kingdom
| | - Andrew A Grace
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Christopher L-H Huang
- Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom.,Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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36
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Lezcano N, Mariángelo JIE, Vittone L, Wehrens XHT, Said M, Mundiña-Weilenmann C. Early effects of Epac depend on the fine-tuning of the sarcoplasmic reticulum Ca 2+ handling in cardiomyocytes. J Mol Cell Cardiol 2018; 114:1-9. [PMID: 29037982 PMCID: PMC5801154 DOI: 10.1016/j.yjmcc.2017.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 09/19/2017] [Accepted: 10/09/2017] [Indexed: 12/30/2022]
Abstract
In cardiac muscle, signaling through cAMP governs many fundamental cellular functions, including contractility, relaxation and automatism. cAMP cascade leads to the activation of the classic protein kinase A but also to the stimulation of the recently discovered exchange protein directly activated by cAMP (Epac). The role of Epac in the regulation of intracellular Ca2+ homeostasis and contractility in cardiac myocytes is still matter of debate. In this study we showed that the selective Epac activator, 8-(4-chloro-phenylthio)-2'-O-methyladenosine-3', 5'-cyclic monophosphate (8-CPT), produced a positive inotropic effect when adult rat cardiac myocytes were stabilized at low [Ca2+]o (0.5mM), no changes at 1mM [Ca2+]o and a negative inotropic effect when [Ca2+]o was increased to 1.8mM. These effects were associated to parallel variations in sarcoplasmic reticulum (SR) Ca2+ content. At all [Ca2+]o studied, 8-CPT induced an increase in Ca2+ spark frequency and enhanced CaMKII autophosphorylation and the CaMKII-dependent phosphorylation of SR proteins: phospholamban (PLN, at Thr17 site) and ryanodine receptor (RyR2, at Ser2814 site). We used transgenic mice lacking PLN CaMKII phosphorylation site (PLN-DM) and knock-in mice with an inactivated CaMKII site S2814 on RyR2 (RyR2-S2814A) to investigate the involvement of these processes in the effects of Epac stimulation. In PLN-DM mice, 8-CPT failed to induce the positive inotropic effect at low [Ca2+]o and RyR2-S2814A mice showed no propensity to arrhythmic events when compared to wild type mice myocytes. We conclude that stimulation of Epac proteins could have either beneficial or deleterious effects depending on the steady-state Ca2+ levels at which the myocyte is functioning, favoring the prevailing mechanism of SR Ca2+ handling (uptake vs. leak) in the different situations.
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Affiliation(s)
- N Lezcano
- Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Argentina
| | - J I E Mariángelo
- Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Argentina
| | - L Vittone
- Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Argentina
| | - X H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, United States
| | - M Said
- Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Argentina
| | - C Mundiña-Weilenmann
- Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Argentina.
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37
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Valli H, Ahmad S, Sriharan S, Dean LD, Grace AA, Jeevaratnam K, Matthews HR, Huang CLH. Epac-induced ryanodine receptor type 2 activation inhibits sodium currents in atrial and ventricular murine cardiomyocytes. Clin Exp Pharmacol Physiol 2017; 45:278-292. [PMID: 29027245 PMCID: PMC5814738 DOI: 10.1111/1440-1681.12870] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/23/2017] [Accepted: 09/27/2017] [Indexed: 12/16/2022]
Abstract
Acute RyR2 activation by exchange protein directly activated by cAMP (Epac) reversibly perturbs myocyte Ca2+ homeostasis, slows myocardial action potential conduction, and exerts pro‐arrhythmic effects. Loose patch‐clamp studies, preserving in vivo extracellular and intracellular conditions, investigated Na+ current in intact cardiomyocytes in murine atrial and ventricular preparations following Epac activation. Depolarising steps to varying test voltages activated typical voltage‐dependent Na+ currents. Plots of peak current against depolarisation from resting potential gave pretreatment maximum atrial and ventricular currents of −20.23 ± 1.48 (17) and −29.8 ± 2.4 (10) pA/μm2 (mean ± SEM [n]). Challenge by 8‐CPT (1 μmol/L) reduced these currents to −11.21 ± 0.91 (12) (P < .004) and −19.3 ± 1.6 (11) pA/μm2 (P < .04) respectively. Currents following further addition of the RyR2 inhibitor dantrolene (10 μmol/L) (−19.91 ± 2.84 (13) and −26.6 ± 1.7 (17)), and dantrolene whether alone (−19.53 ± 1.97 (8) and −27.6 ± 1.9 (14)) or combined with 8‐CPT (−19.93 ± 2.59 (12) and −29.9 ± 2.5(11)), were indistinguishable from pretreatment values (all P >> .05). Assessment of the inactivation that followed by applying subsequent steps to a fixed voltage 100 mV positive to resting potential gave concordant results. Half‐maximal inactivation voltages and steepness factors, and time constants for Na+ current recovery from inactivation in double‐pulse experiments, were similar through all the pharmacological conditions. Intracellular sharp microelectrode membrane potential recordings in intact Langendorff‐perfused preparations demonstrated concordant variations in maximum rates of atrial and ventricular action potential upstroke, (dV/dt)max. We thus demonstrate an acute, reversible, Na+ channel inhibition offering a possible mechanism for previously reported pro‐arrhythmic slowing of AP propagation following modifications of Ca2+ homeostasis, complementing earlier findings from chronic alterations in Ca2+ homeostasis in genetically‐modified RyR2‐P2328S hearts.
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Affiliation(s)
- Haseeb Valli
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Shiraz Ahmad
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Sujan Sriharan
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Lydia D Dean
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Andrew A Grace
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Kamalan Jeevaratnam
- Physiological Laboratory, University of Cambridge, Cambridge, UK.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK.,PU-RCSI School of Medicine, Perdana University, Serdang, Selangor Darul Ehsan, Malaysia
| | - Hugh R Matthews
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Christopher L-H Huang
- Physiological Laboratory, University of Cambridge, Cambridge, UK.,Department of Biochemistry, University of Cambridge, Cambridge, UK
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38
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Rehmann H. Interaction of Epac with Non-canonical Cyclic Nucleotides. Handb Exp Pharmacol 2017; 238:135-147. [PMID: 27900608 DOI: 10.1007/164_2015_37] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Epac1 and Epac2 are cyclic nucleotide-binding (CNB) domain containing proteins, which were originally identified as cAMP-regulated guanine nucleotide exchange factors (GEFs) for the small G-protein Rap. Therefore, Epac proteins founded next to protein kinase A (PKA) and cyclic nucleotide-regulated ion channels the third group of cAMP-responsive proteins in higher organisms. Epac proteins are involved in the regulation of several physiological processes. In particular Epac1 mediates the regulation of molecular processes underlying cell adhesion and mobility. In the pancreas activation of Epac2 potentiates the release of glucose-induced insulin secretion and received attention as a putative target for antidiabetic treatment. While the regulation of Epac by cAMP has been analysed in structural and biochemical detail, less is known on the interaction of Epac with non-canonical cyclic nucleotides. This chapter will discuss to what extent other cyclic purines than cAMP or cyclic pyrimidine could act as Epac agonists or antagonists. The focus will be on the biophysical analysis of the interaction between Epac and these cyclic nucleotides.
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Affiliation(s)
- Holger Rehmann
- Molecular Cancer Research and Cancer Genomics Netherlands, Center for Molecular Medicine, UMC Utrecht, Utrecht, The Netherlands.
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39
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Yang Z, Kirton HM, Al-Owais M, Thireau J, Richard S, Peers C, Steele DS. Epac2-Rap1 Signaling Regulates Reactive Oxygen Species Production and Susceptibility to Cardiac Arrhythmias. Antioxid Redox Signal 2017; 27:117-132. [PMID: 27649969 PMCID: PMC5510674 DOI: 10.1089/ars.2015.6485] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 09/19/2016] [Accepted: 09/19/2016] [Indexed: 12/19/2022]
Abstract
AIMS In the heart, β1-adrenergic signaling involves cyclic adenosine monophosphate (cAMP) acting via both protein kinase-A (PKA) and exchange protein directly activated by cAMP (Epac): a guanine nucleotide exchange factor for the small GTPase Rap1. Inhibition of Epac-Rap1 signaling has been proposed as a therapeutic strategy for both cancer and cardiovascular disease. However, previous work suggests that impaired Rap1 signaling may have detrimental effects on cardiac function. The aim of the present study was to investigate the influence of Epac2-Rap1 signaling on the heart using both in vivo and in vitro approaches. RESULTS Inhibition of Epac2 signaling induced early afterdepolarization arrhythmias in ventricular myocytes. The underlying mechanism involved an increase in mitochondrial reactive oxygen species (ROS) and activation of the late sodium current (INalate). Arrhythmias were blocked by inhibition of INalate or the mitochondria-targeted antioxidant, mitoTEMPO. In vivo, inhibition of Epac2 caused ventricular tachycardia, torsades de pointes, and sudden death. The in vitro and in vivo effects of Epac2 inhibition were mimicked by inhibition of geranylgeranyltransferase-1, which blocks interaction of Rap1 with downstream targets. INNOVATION Our findings show for the first time that Rap1 acts as a negative regulator of mitochondrial ROS production in the heart and that impaired Epac2-Rap1 signaling causes arrhythmias due to ROS-dependent activation of INalate. This has implications for the use of chemotherapeutics that target Epac2-Rap1 signaling. However, selective inhibition of INalate provides a promising strategy to prevent arrhythmias caused by impaired Epac2-Rap1 signaling. CONCLUSION Epac2-Rap1 signaling attenuates mitochondrial ROS production and reduces myocardial arrhythmia susceptibility. Antioxid. Redox Signal. 27, 117-132.
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Affiliation(s)
- Zhaokang Yang
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Hannah M. Kirton
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Moza Al-Owais
- Division of Cardiovascular Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Jérôme Thireau
- PHYMEDEXP, Physiologie et Médecine Expérimentale, Cœur et Muscles, INSERM U1046, CNRS UMR 9214, Université de Montpellier, Montpellier, France
| | - Sylvain Richard
- PHYMEDEXP, Physiologie et Médecine Expérimentale, Cœur et Muscles, INSERM U1046, CNRS UMR 9214, Université de Montpellier, Montpellier, France
| | - Chris Peers
- Division of Cardiovascular Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Derek S. Steele
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
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40
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Shoshan-Barmatz V, Krelin Y, Shteinfer-Kuzmine A. VDAC1 functions in Ca 2+ homeostasis and cell life and death in health and disease. Cell Calcium 2017; 69:81-100. [PMID: 28712506 DOI: 10.1016/j.ceca.2017.06.007] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/21/2017] [Accepted: 06/21/2017] [Indexed: 01/15/2023]
Abstract
In the outer mitochondrial membrane (OMM), the voltage-dependent anion channel 1 (VDAC1) serves as a mitochondrial gatekeeper, controlling the metabolic and energy cross-talk between mitochondria and the rest of the cell. VDAC1 also functions in cellular Ca2+ homeostasis by transporting Ca2+ in and out of mitochondria. VDAC1 has also been recognized as a key protein in mitochondria-mediated apoptosis, contributing to the release of apoptotic proteins located in the inter-membranal space (IMS) and regulating apoptosis via association with pro- and anti-apoptotic members of the Bcl-2 family of proteins and hexokinase. VDAC1 is highly Ca2+-permeable, transporting Ca2+ to the IMS and thus modulating Ca2+ access to Ca2+ transporters in the inner mitochondrial membrane. Intra-mitochondrial Ca2+ controls energy metabolism via modulating critical enzymes in the tricarboxylic acid cycle and in fatty acid oxidation. Ca2+ also determines cell sensitivity to apoptotic stimuli and promotes the release of pro-apoptotic proteins. However, the precise mechanism by which intracellular Ca2+ mediates apoptosis is not known. Here, the roles of VDAC1 in mitochondrial Ca2+ homeostasis are presented while emphasizing a new proposed mechanism for the mode of action of pro-apoptotic drugs. This view, proposing that Ca2+-dependent enhancement of VDAC1 expression levels is a major mechanism by which apoptotic stimuli induce apoptosis, position VDAC1 oligomerization at a molecular focal point in apoptosis regulation. The interactions of VDAC1 with many proteins involved in Ca2+ homeostasis or regulated by Ca2+, as well as VDAC-mediated control of cell life and death and the association of VDAC with disease, are also presented.
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Affiliation(s)
- Varda Shoshan-Barmatz
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
| | - Yakov Krelin
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Anna Shteinfer-Kuzmine
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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41
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Pereira L, Bare DJ, Galice S, Shannon TR, Bers DM. β-Adrenergic induced SR Ca 2+ leak is mediated by an Epac-NOS pathway. J Mol Cell Cardiol 2017; 108:8-16. [PMID: 28476660 DOI: 10.1016/j.yjmcc.2017.04.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 04/26/2017] [Accepted: 04/27/2017] [Indexed: 02/08/2023]
Abstract
Cardiac β-adrenergic receptors (β-AR) and Ca2+-Calmodulin dependent protein kinase (CaMKII) regulate both physiological and pathophysiological Ca2+ signaling. Elevated diastolic Ca2+ leak from the sarcoplasmic reticulum (SR) contributes to contractile dysfunction in heart failure and to arrhythmogenesis. β-AR activation is known to increase SR Ca2+ leak via CaMKII-dependent phosphorylation of the ryanodine receptor. Two independent and reportedly parallel pathways have been implicated in this β-AR-CaMKII cascade, one involving exchange protein directly activated by cAMP (Epac2) and another involving nitric oxide synthase 1 (NOS1). Here we tested whether Epac and NOS function in a single series pathway to increase β-AR induced and CaMKII-dependent SR Ca2+ leak. Leak was measured as both Ca2+ spark frequency and tetracaine-induced shifts in SR Ca2+, in mouse and rabbit ventricular myocytes. Direct Epac activation by 8-CPT (8-(4-chlorophenylthio)-2'-O-methyl-cAMP) mimicked β-AR-induced SR Ca2+ leak, and both were blocked by NOS inhibition. The same was true for myocyte CaMKII activation (assessed via a FRET-based reporter) and ryanodine receptor phosphorylation. Inhibitor and phosphorylation studies also implicated phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt) downstream of Epac and above NOS activation in this pathway. We conclude that these two independently characterized parallel pathways function mainly via a single series arrangement (β-AR-cAMP-Epac-PI3K-Akt-NOS1-CaMKII) to mediate increased SR Ca2+ leak. Thus, for β-AR activation the cAMP-PKA branch effects inotropy and lusitropy (by effects on Ca2+ current and SR Ca2+-ATPase), this cAMP-Epac-NOS pathway increases pathological diastolic SR Ca2+leak. This pathway distinction may allow novel SR Ca2+ leak therapeutic targeting in treatment of arrhythmias in heart failure that spare the inotropic and lusitropic effects of the PKA branch.
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Affiliation(s)
- Laëtitia Pereira
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, United States
| | - Dan J Bare
- Department of Molecular Biophysics and Physiology, Rush University, Chicago, IL 60612, United States
| | - Samuel Galice
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, United States
| | - Thomas R Shannon
- Department of Molecular Biophysics and Physiology, Rush University, Chicago, IL 60612, United States.
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, United States.
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42
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Galaz-Montoya M, Wright SJ, Rodriguez GJ, Lichtarge O, Wensel TG. β 2-Adrenergic receptor activation mobilizes intracellular calcium via a non-canonical cAMP-independent signaling pathway. J Biol Chem 2017; 292:9967-9974. [PMID: 28442571 DOI: 10.1074/jbc.m117.787119] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 04/24/2017] [Indexed: 11/06/2022] Open
Abstract
Beta adrenergic receptors (βARs) are G-protein-coupled receptors essential for physiological responses to the hormones/neurotransmitters epinephrine and norepinephrine which are found in the nervous system and throughout the body. They are the targets of numerous widely used drugs, especially in the case of the most extensively studied βAR, β2AR, whose ligands are used for asthma and cardiovascular disease. βARs signal through Gαs G-proteins and via activation of adenylyl cyclase and cAMP-dependent protein kinase, but some alternative downstream pathways have also been proposed that could be important for understanding normal physiological functioning of βAR signaling and its disruption in disease. Using fluorescence-based Ca2+ flux assays combined with pharmacology and gene knock-out methods, we discovered a previously unrecognized endogenous pathway in HEK-293 cells whereby β2AR activation leads to robust Ca2+ mobilization from intracellular stores via activation of phospholipase C and opening of inositol trisphosphate (InsP3) receptors. This pathway did not involve cAMP, Gαs, or Gαi or the participation of the other members of the canonical β2AR signaling cascade and, therefore, constitutes a novel signaling mechanism for this receptor. This newly uncovered mechanism for Ca2+ mobilization by β2AR has broad implications for adrenergic signaling, cross-talk with other signaling pathways, and the effects of βAR-directed drugs.
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Affiliation(s)
- Monica Galaz-Montoya
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology and
| | - Sara J Wright
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology and
| | - Gustavo J Rodriguez
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology and
| | - Olivier Lichtarge
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology and.,the Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
| | - Theodore G Wensel
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology and
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43
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Wang P, Liu Z, Chen H, Ye N, Cheng X, Zhou J. Exchange proteins directly activated by cAMP (EPACs): Emerging therapeutic targets. Bioorg Med Chem Lett 2017; 27:1633-1639. [PMID: 28283242 PMCID: PMC5397994 DOI: 10.1016/j.bmcl.2017.02.065] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/07/2017] [Accepted: 02/26/2017] [Indexed: 11/22/2022]
Abstract
Exchange proteins directly activated by cAMP (EPACs) are critical cAMP-dependent signaling pathway mediators. The discovery of EPAC proteins has significantly facilitated understanding on cAMP-dependent signaling pathway and efforts along this line open new avenues for developing novel therapeutics for cancer, diabetes, heart failure, inflammation, infections, neurological disorders and other human diseases. Over the past decade, important progress has been made in the identification of EPAC agonists, antagonists and their biological and pharmacological applications. In this review, we briefly summarize recently reported novel functions of EPACs and the discovery of their small molecule modulators. The challenges and future perspectives are also discussed.
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Affiliation(s)
- Pingyuan Wang
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, United States
| | - Zhiqing Liu
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, United States
| | - Haiying Chen
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, United States
| | - Na Ye
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, United States
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, University of Texas Health Science Center, Houston, TX 77030, United States
| | - Jia Zhou
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, United States.
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44
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Khan I, Ali A, Akhter MA, Naeem N, Chotani MA, Iqbal H, Kabir N, Atiq M, Salim A. Epac-Rap1-activated mesenchymal stem cells improve cardiac function in rat model of myocardial infarction. Cardiovasc Ther 2017; 35. [PMID: 28039940 DOI: 10.1111/1755-5922.12248] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
INTRODUCTION Rap1, a member of Ras superfamily of small GTP-binding proteins, is involved in cardiovascular biology in numerous ways. It is an evolutionary conserved regulator of adhesion, polarity, differentiation and growth. AIMS Our aim was to analyze Rap1-activated rat bone marrow mesenchymal stem cells (MSCs) for their potential role in adhesion and cardiac differentiation. METHODS Myocardial infarction (MI) was produced in Sprague Dawley (SD) rats through occlusion of the left anterior descending coronary artery. MSCs were treated with 8-pCPT-2'-O-Me-cAMP (CPT) to activate Rap1. Normal (untreated) and CPT-treated MSCs were transplanted through intramyocardial injection in respective groups. Cardiac function was assessed by echocardiography at 2 and 4 weeks after cell transplantation. Histological analysis was performed to observe changes at tissue level. RESULTS Homing of CPT-treated MSCs was significantly (***P<.001) higher as compared to normal MSCs in the infarcted hearts. This may be due to increase in the gene expression of some of the cell adhesion molecules as evident by qRT-PCR analysis. Significant (***P<.001) improvement in the restoration of heart function in terms of left ventricular diastolic and systolic internal diameters (LVIDd, LVIDs), % ejection fraction, % fraction shortening and end-systolic and end-diastolic volumes were observed in CPT-treated MSCs as compared to the MI model. Histological analyses showed significant (***P<.001) reduction in scar formation in the CPT-treated group. Differentiation of treated MSCs into functional cardiomyocytes was evident through immunohistochemical staining. LV wall thickness was also preserved significantly (***P<.001). Blood vessel formation was more pronounced in CPT-treated group although both cell therapy groups showed significant increase as compared to MI model. CONCLUSION Our findings showed that pharmacological activation of Epac-Rap1 improves cardiac function through better survival, adhesion and differentiation of transplanted cells. Transplantation of these MSCs in the infarct area restored functional myocardium.
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Affiliation(s)
- Irfan Khan
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Anwar Ali
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Muhammad Aleem Akhter
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Nadia Naeem
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Maqsood Ahmed Chotani
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan.,Center for Cardiovascular & Pulmonary Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Hana'a Iqbal
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Nurul Kabir
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Mehnaz Atiq
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Asmat Salim
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
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Park SJ, Ahmad F, Um JH, Brown AL, Xu X, Kang H, Ke H, Feng X, Ryall J, Philp A, Schenk S, Kim MK, Sartorelli V, Chung JH. Specific Sirt1 Activator-mediated Improvement in Glucose Homeostasis Requires Sirt1-Independent Activation of AMPK. EBioMedicine 2017; 18:128-138. [PMID: 28396013 PMCID: PMC5405165 DOI: 10.1016/j.ebiom.2017.03.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 03/10/2017] [Accepted: 03/10/2017] [Indexed: 12/15/2022] Open
Abstract
The specific Sirt1 activator SRT1720 increases mitochondrial function in skeletal muscle, presumably by activating Sirt1. However, Sirt1 gain of function does not increase mitochondrial function, which raises a question about the central role of Sirt1 in SRT1720 action. Moreover, it is believed that the metabolic effects of SRT1720 occur independently of AMP-activated protein kinase (AMPK), an important metabolic regulator that increases mitochondrial function. Here, we show that SRT1720 activates AMPK in a Sirt1-independent manner and SRT1720 activates AMPK by inhibiting a cAMP degrading phosphodiesterase (PDE) in a competitive manner. Inhibiting the cAMP effector protein Epac prevents SRT1720 from activating AMPK or Sirt1 in myotubes. Moreover, SRT1720 does not increase mitochondrial function or improve glucose tolerance in AMPKα2 knockout mice. Interestingly, weight loss induced by SRT1720 is not sufficient to improve glucose tolerance. Therefore, contrary to current belief, the metabolic effects produced by SRT1720 require AMPK, which can be activated independently of Sirt1. SRT1720 activates AMPK in a Sirt1-independent manner. SRT1720 activates AMPK by inhibiting cAMP phosphodiesterase. SRT1720-mediated improvement in glucose homeostasis requires AMPK. Weight loss due to SRT1720 is not sufficient for improved glucose homeostasis.
Obesity has become an epidemic and obesity-related diseases such as type 2 diabetes are on the rise. Therefore, discovering novel therapies for these diseases will have great public health impact. Sirt1 activating compounds such as SRT1720 protect against obesity and glucose intolerance, but the mechanism by which they confer these health benefits has been unclear. We discovered that SRT1720 activates energy sensor AMPK, independent of Sirt1, and increases mitochondrial function and glucose tolerance in an AMPK-dependent manner. SRT1720 activates AMPK by directly inhibiting cAMP phosphodiesterases, suggesting that cAMP phosphodiesterases may be potential drug targets for obesity-related diseases.
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Affiliation(s)
- Sung-Jun Park
- Laboratory of Obesity and Aging Research, Genetics and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Faiyaz Ahmad
- Translational Medicine Branch, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jee-Hyun Um
- Laboratory of Obesity and Aging Research, Genetics and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alexandra L Brown
- Laboratory of Obesity and Aging Research, Genetics and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xihui Xu
- Laboratory of Obesity and Aging Research, Genetics and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hyeog Kang
- Laboratory of Obesity and Aging Research, Genetics and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hengming Ke
- Department of Biochemistry and Biophysics, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Xuesong Feng
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - James Ryall
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andrew Philp
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Simon Schenk
- Department of Orthopedic Surgery, University of California San Diego, La Jolla, CA 92093, USA
| | - Myung K Kim
- Laboratory of Obesity and Aging Research, Genetics and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Vittorio Sartorelli
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jay H Chung
- Laboratory of Obesity and Aging Research, Genetics and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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The Epac-Phospholipase Cε Pathway Regulates Endocannabinoid Signaling and Cocaine-Induced Disinhibition of Ventral Tegmental Area Dopamine Neurons. J Neurosci 2017; 37:3030-3044. [PMID: 28209735 DOI: 10.1523/jneurosci.2810-16.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 01/26/2017] [Accepted: 02/06/2017] [Indexed: 11/21/2022] Open
Abstract
Exchange protein directly activated by cAMP (Epac) is a direct effector for the ubiquitous second messenger cAMP. Epac activates the phospholipase Cε (PLCε) pathway. PLCβ has been linked to the synthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG). Here, we report that Epac facilitates endocannabinoid-mediated retrograde synaptic depression through activation of PLCε. Intracellular loading of a selective Epac agonist 8-CPT-2Me-cAMP into ventral tegmental area (VTA) dopamine neurons enabled previously ineffective stimuli to induce depolarization-induced suppression of inhibition (DSI) and long-term depression of IPSCs (I-LTD) in the VTA. DSI and I-LTD are mediated by 2-AG since they were blocked by a diacylglycerol lipase inhibitor. The effects of 8-CPT-2Me-cAMP on DSI and I-LTD were absent in Epac2 and PLCε knock-out mice, but remained intact in Epac1 knock-out mice. These results identify a novel mechanism for on-demand synthesis of retrograde signaling 2-AG by the Epac2-PLCε pathway. We investigated the functional significance of Epac2-PLCε-2-AG signaling in regulating inhibitory synaptic plasticity in VTA dopamine neurons induced by in vivo cocaine exposure. We showed that cocaine place conditioning led to a decrease in the frequency and amplitude of spontaneous IPSCs and an increase in action potential firing in wild-type mice, but not in Epac2 or PLCε knock-out mice. Together, these results indicate that the Epac2-PLCε-2-AG signaling cascade contributes to cocaine-induced disinhibition of VTA dopamine neurons.SIGNIFICANCE STATEMENT 2-arachidonoylglycerol (2-AG) is an endogenous cannabinoid that depresses synaptic transmission through stimulation of CB1 receptors. Among the six isoforms of phospholipase C (PLC; PLCβ, PLCγ, PLCδ, PLCε, PLCζ, PLCη), only PLCβ has been linked to 2-AG synthesis. Here we demonstrate that 8-CPT-2Me-cAMP, a selective agonist of the cAMP sensor protein Epac, enhances 2-AG-mediated synaptic depression in ventral tegmental area (VTA) dopamine neurons via activation of PLCε. These results identify a novel mechanism for 2-AG synthesis via activation of the Epac-PLCε pathway. Furthermore, we show that cocaine-induced conditioned place preference and disinhibition of VTA dopamine neurons were impaired in mice lacking Epac or PLCε. Thus, the Epac-PLCε signaling pathway contributes to cocaine-induced disinhibition of VTA dopamine neurons and formation of drug-associated memories.
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Fujita T, Umemura M, Yokoyama U, Okumura S, Ishikawa Y. The role of Epac in the heart. Cell Mol Life Sci 2017; 74:591-606. [PMID: 27549789 PMCID: PMC11107744 DOI: 10.1007/s00018-016-2336-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 07/21/2016] [Accepted: 08/09/2016] [Indexed: 02/08/2023]
Abstract
As one of the most important second messengers, 3',5'-cyclic adenosine monophosphate (cAMP) mediates various extracellular signals including hormones and neurotransmitters, and induces appropriate responses in diverse types of cells. Since cAMP was formerly believed to transmit signals through only two direct target molecules, protein kinase A and the cyclic nucleotide-gated channel, the sensational discovery in 1998 of another novel direct effecter of cAMP [exchange proteins directly activated by cAMP (Epac)] attracted a great deal of scientific interest in cAMP signaling. Numerous studies on Epac have since disclosed its important functions in various tissues in the body. Recently, observations of genetically manipulated mice in various pathogenic models have begun to reveal the in vivo significance of previous in vitro or cellular-level findings. Here, we focused on the function of Epac in the heart. Accumulating evidence has revealed that both Epac1 and Epac2 play important roles in the structure and function of the heart under physiological and pathological conditions. Accordingly, developing the ability to regulate cAMP-mediated signaling through Epac may lead to remarkable new therapies for the treatment of cardiac diseases.
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Affiliation(s)
- Takayuki Fujita
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
| | - Masanari Umemura
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Utako Yokoyama
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Satoshi Okumura
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Yoshihiro Ishikawa
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
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Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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49
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Mangmool S, Denkaew T, Parichatikanond W, Kurose H. β-Adrenergic Receptor and Insulin Resistance in the Heart. Biomol Ther (Seoul) 2017; 25:44-56. [PMID: 28035081 PMCID: PMC5207462 DOI: 10.4062/biomolther.2016.128] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/26/2016] [Accepted: 08/02/2016] [Indexed: 12/24/2022] Open
Abstract
Insulin resistance is characterized by the reduced ability of insulin to stimulate tissue uptake and disposal of glucose including cardiac muscle. These conditions accelerate the progression of heart failure and increase cardiovascular morbidity and mortality in patients with cardiovascular diseases. It is noteworthy that some conditions of insulin resistance are characterized by up-regulation of the sympathetic nervous system, resulting in enhanced stimulation of β-adrenergic receptor (βAR). Overstimulation of βARs leads to the development of heart failure and is associated with the pathogenesis of insulin resistance in the heart. However, pathological consequences of the cross-talk between the βAR and the insulin sensitivity and the mechanism by which βAR overstimulation promotes insulin resistance remain unclear. This review article examines the hypothesis that βARs overstimulation leads to induction of insulin resistance in the heart.
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Affiliation(s)
- Supachoke Mangmool
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand.,Center of Excellence for Innovation in Drug Design and Discovery, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand
| | - Tananat Denkaew
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand
| | | | - Hitoshi Kurose
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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50
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Edland F, Wergeland A, Kopperud R, Åsrud KS, Hoivik EA, Witsø SL, Æsøy R, Madsen L, Kristiansen K, Bakke M, Døskeland SO, Jonassen AK. Long-term consumption of an obesogenic high fat diet prior to ischemia-reperfusion mediates cardioprotection via Epac1-dependent signaling. Nutr Metab (Lond) 2016; 13:87. [PMID: 27933093 PMCID: PMC5127093 DOI: 10.1186/s12986-016-0147-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 11/17/2016] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Obesity is still considered a risk factor for cardiovascular disease, although more recent knowledge also suggests obesity to be associated with reduced morbidity and mortality - the "obesity paradox". This study explores if long-term feeding of an obesogenic high fat diet renders the myocardium less susceptible to ischemic-reperfusion induced injury via Epac-dependent signaling. METHODS Wild type (wt), Epac1 (Epac1-/-) and Epac2 (Epac2-/-) deficient mice were fed a high fat (HFD) or normal chow diet (ND) for 33 ± 1 weeks. Six experimental groups were included: (1) control wt ND (wt ND), (2) control wt HFD (wt HFD), (3) Epac1-/- mice on ND (Epac1-/-ND), (4) Epac1-/- mice on HFD (Epac1-/-HFD), (5) Epac2-/- mice on ND (Epac2-/-ND), and (6) Epac2-/- mice on HFD (Epac2-/-HFD). Isolated ex vivo mice hearts were perfused in a constant pressure Langendorff mode, and exposed to 30min of global ischemia (GI) and 60min of reperfusion. Endpoints were infarct size and functional recovery. RESULTS All groups fed a HFD presented with significantly enhanced body weight, visceral fat content and reduced glucose clearance compared to corresponding ND groups. Although the HFD cohorts presented with an overall comparable systemic capability to clear glucose, the Epac1-/- HFD group presented with glucose levels slightly above the human diabetes criteria at the end of the intraperitoneal glucose tolerance test (ipGTT). Moreover, the HFD significantly reduced infarct size in both wild type (wt HFD 41.3 ± 5.5% vs. wt ND 58.0 ± 9.8%, p < 0.05) and Epac2-/- cohorts (Epac2-/-HFD 34.4 ± 7.2% vs. Epac2-/-ND 56.5 ± 3.8%, p < 0.05). Interestingly, however, the HFD did not reduce infarct size in Epac1-/- deficient mice hearts (Epac1-/-HFD 65.1 ± 5.1% vs. Epac1-/-ND 56.1 ± 3.5%, ns.). CONCLUSION Epac1-dependent signaling is involved in mediating the cardioprotection afforded by long-term feeding of an obesogenic high fat diet in mice hearts.
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Affiliation(s)
- F Edland
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
| | - A Wergeland
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
| | - R Kopperud
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
| | - K S Åsrud
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
| | - E A Hoivik
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
| | - S L Witsø
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
| | - R Æsøy
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
| | - L Madsen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark ; National Institute of Nutrition and Seafood Research, Bergen, Norway
| | - K Kristiansen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - M Bakke
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
| | - S O Døskeland
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
| | - A K Jonassen
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway ; Faculty of Health Science and Medicine, Norwegian University of Science and Technology, NTNU, Trondheim, Norway
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