1
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Nakamura N, Honjo M, Yamagishi-Kimura R, Sakata R, Watanabe S, Aihara M. Neuroprotective effect of omidenepag on excitotoxic retinal ganglion cell death regulating COX-2-EP2-cAMP-PKA/Epac pathway via Neuron-Glia interaction. Neuroscience 2024; 553:145-159. [PMID: 38992567 DOI: 10.1016/j.neuroscience.2024.07.006] [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: 10/18/2023] [Revised: 06/03/2024] [Accepted: 07/04/2024] [Indexed: 07/13/2024]
Abstract
Glutamate excitotoxicity is involved in retinal ganglion cell (RGC) death in various retinal degenerative diseases, including ischemia-reperfusion injury and glaucoma. Excitotoxic RGC death is caused by both direct damage to RGCs and indirect damage through neuroinflammation of retinal glial cells. Omidenepag (OMD), a novel E prostanoid receptor 2 (EP2) agonist, is a recently approved intraocular pressure-lowering drug. The second messenger of EP2 is cyclic adenosine monophosphate (cAMP), which activates protein kinase A (PKA) and exchange protein directly activated by cAMP (Epac). In this study, we investigated the neuroprotective effects of OMD on excitotoxic RGC death by focusing on differences in cAMP downstream signaling from the perspective of glia-neuron interactions. We established a glutamate excitotoxicity model in vitro and NMDA intravitreal injection model in vivo. In vitro, rat primary RGCs were used in an RGC survival rate assay. MG5 cells (mouse microglial cell line) and A1 cells (astrocyte cell line) were used for immunocytochemistry and Western blotting to evaluate the expressions of COX-1/2, PKA, Epac1/2, pCREB, cleaved caspase-3, inflammatory cytokines, and neurotrophic factors. Mouse retinal specimens underwent hematoxylin and eosin staining, flat-mounted retina examination, and immunohistochemistry. OMD significantly suppressed excitotoxic RGC death, cleaved caspase-3 expression, and activated glia both in vitro and in vivo. Moreover, it inhibited Epac1 and inflammatory cytokine expression and promoted COX-2, pCREB, and neurotrophic factor expression. OMD may have neuroprotective effects through inhibition of the Epac pathway and promotion of the COX-2-EP2-cAMP-PKA pathway by modulating glia-neuron interaction.
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Affiliation(s)
- Natsuko Nakamura
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Division of Vision Research, National Institute of Sensory Organs, NHO Tokyo Medical Center, Tokyo, Japan; Department of Ophthalmology, Kobe City Eye Hospital, Kobe, Japan
| | - Megumi Honjo
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
| | - Reiko Yamagishi-Kimura
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Rei Sakata
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Sumiko Watanabe
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Makoto Aihara
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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2
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Walker V. The Intricacies of Renal Phosphate Reabsorption-An Overview. Int J Mol Sci 2024; 25:4684. [PMID: 38731904 PMCID: PMC11083860 DOI: 10.3390/ijms25094684] [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: 03/24/2024] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 05/13/2024] Open
Abstract
To maintain an optimal body content of phosphorus throughout postnatal life, variable phosphate absorption from food must be finely matched with urinary excretion. This amazing feat is accomplished through synchronised phosphate transport by myriads of ciliated cells lining the renal proximal tubules. These respond in real time to changes in phosphate and composition of the renal filtrate and to hormonal instructions. How they do this has stimulated decades of research. New analytical techniques, coupled with incredible advances in computer technology, have opened new avenues for investigation at a sub-cellular level. There has been a surge of research into different aspects of the process. These have verified long-held beliefs and are also dramatically extending our vision of the intense, integrated, intracellular activity which mediates phosphate absorption. Already, some have indicated new approaches for pharmacological intervention to regulate phosphate in common conditions, including chronic renal failure and osteoporosis, as well as rare inherited biochemical disorders. It is a rapidly evolving field. The aim here is to provide an overview of our current knowledge, to show where it is leading, and where there are uncertainties. Hopefully, this will raise questions and stimulate new ideas for further research.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton S016 6YD, UK
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3
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Shiozaki‐Takagi Y, Ozaki N, Toyoda Y. Epac2 activation mediates glucagon-induced glucogenesis in primary rat hepatocytes. J Diabetes Investig 2024; 15:429-436. [PMID: 38243676 PMCID: PMC10981141 DOI: 10.1111/jdi.14142] [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: 10/03/2023] [Revised: 12/06/2023] [Accepted: 12/21/2023] [Indexed: 01/21/2024] Open
Abstract
AIMS/INTRODUCTION Glucagon plays an essential role in hepatic glucogenesis by enhancing glycogen breakdown, inducing gluconeogenesis, and suppressing glycogenesis. Moreover, glucagon increases cyclic adenosine monophosphate (cAMP) levels, thereby activating protein kinase A (PKA) and cAMP guanine nucleotide exchange factor (also known as Epac). Although the function of PKA in the liver has been studied extensively, the function of hepatic Epac is poorly understood. The aim of this study was to elucidate the role of Epac in mediating the action of glucagon on the hepatocytes. MATERIALS AND METHODS Epac mRNA and protein expression, localization, and activity in the hepatocytes were analyzed by reverse transcription polymerase chain reaction, western blotting, immunofluorescence staining, and Rap1 activity assay, respectively. Additionally, we investigated the effects of an Epac-specific activator, 8-CPT, and an Epac-specific inhibitor, ESI-05, on glycogen metabolism in isolated rat hepatocytes. Further mechanisms of glycogen metabolism were evaluated by examining glucokinase (GK) translocation and mRNA expression of gluconeogenic enzymes. RESULTS Epac2, but not Epac1, was predominantly expressed in the liver. Moreover, 8-CPT inhibited glycogen accumulation and GK translocation and enhanced the mRNA expression of gluconeogenic enzymes. ESI-05 failed to reverse glucagon-induced suppression of glycogen storage and partially inhibited glucagon-induced GK translocation and the mRNA expression of gluconeogenic enzymes. CONCLUSIONS Epac signaling plays a role in mediating the glucogenic action of glucagon in the hepatocytes.
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Affiliation(s)
- Yusuke Shiozaki‐Takagi
- Research Center of Health, Physical Fitness and SportsNagoya UniversityNagoyaJapan
- Department of Pathobiochemistry, Faculty of PharmacyMeijo UniversityNagoyaJapan
- Present address:
Division of Cell Signaling and Molecular Medicine, Institute of Medical ScienceThe University of TokyoTokyoJapan
| | - Nobuaki Ozaki
- Research Center of Health, Physical Fitness and SportsNagoya UniversityNagoyaJapan
- Division of EndocrinologyJapanese Red Cross Aichi Medical Center Nagoya Daiichi HospitalNagoyaJapan
| | - Yukiyasu Toyoda
- Department of Pathobiochemistry, Faculty of PharmacyMeijo UniversityNagoyaJapan
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4
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Jiang C, Zhao J, Zhang Y, Zhu X. Role of EPAC1 in chronic pain. Biochem Biophys Rep 2024; 37:101645. [PMID: 38304575 PMCID: PMC10832381 DOI: 10.1016/j.bbrep.2024.101645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 01/08/2024] [Accepted: 01/10/2024] [Indexed: 02/03/2024] Open
Abstract
Chronic pain usually lasts over three months and commonly occurs in chronic diseases (cancer, arthritis, and diabetes), injuries (herniated discs, torn ligaments), and many major pain disorders (neuropathic pain, fibromyalgia, chronic headaches). Unfortunately, there is currently a lack of effective treatments to help people with chronic pain to achieve complete relief. Therefore,it is particularly important to understand the mechanism of chronic pain and find new therapeutic targets. The exchange protein directly activated by cyclic adenosine monophosphate(cAMP) (EPAC) has been recognized for its functions in nerve regeneration, stimulating insulin release, controlling vascular pressure, and controlling other metabolic activities. In recent years, many studies have found that the subtype of EPAC, EPAC1 is involved in the regulation of neuroinflammation and plays a crucial role in the regulation of pain, which is expected to become a new therapeutic target for chronic pain. This article reviews the major contributions of EPAC1 in chronic pain.
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Affiliation(s)
- Chenlu Jiang
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, 226001, China
- Medical School of Nantong University, Nantong, 226001, China
| | - Jiacheng Zhao
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, 226001, China
- Medical School of Nantong University, Nantong, 226001, China
| | - Yihang Zhang
- Medical School of Nantong University, Nantong, 226001, China
| | - Xiang Zhu
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, 226001, China
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5
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Cherra SJ, Lamb R. Interactions between Ras and Rap signaling pathways during neurodevelopment in health and disease. Front Mol Neurosci 2024; 17:1352731. [PMID: 38463630 PMCID: PMC10920261 DOI: 10.3389/fnmol.2024.1352731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/08/2024] [Indexed: 03/12/2024] Open
Abstract
The Ras family of small GTPases coordinates tissue development by modulating cell proliferation, cell-cell adhesion, and cellular morphology. Perturbations of any of these key steps alter nervous system development and are associated with neurological disorders. While the underlying causes are not known, genetic mutations in Ras and Rap GTPase signaling pathways have been identified in numerous neurodevelopmental disorders, including autism spectrum, neurofibromatosis, intellectual disability, epilepsy, and schizophrenia. Despite diverse clinical presentations, intersections between these two signaling pathways may provide a better understanding of how deviations in neurodevelopment give rise to neurological disorders. In this review, we focus on presynaptic and postsynaptic functions of Ras and Rap GTPases. We highlight various roles of these small GTPases during synapse formation and plasticity. Based on genomic analyses, we discuss how disease-related mutations in Ras and Rap signaling proteins may underlie human disorders. Finally, we discuss how recent observations have identified molecular interactions between these pathways and how these findings may provide insights into the mechanisms that underlie neurodevelopmental disorders.
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Affiliation(s)
- Salvatore J. Cherra
- Department of Neuroscience, University of Kentucky College of Medicine, Lexington, KY, United States
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6
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Zhang T, Dolga AM, Eisel ULM, Schmidt M. Novel crosstalk mechanisms between GluA3 and Epac2 in synaptic plasticity and memory in Alzheimer's disease. Neurobiol Dis 2024; 191:106389. [PMID: 38142840 DOI: 10.1016/j.nbd.2023.106389] [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: 11/23/2023] [Revised: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease which accounts for the most cases of dementia worldwide. Impaired memory, including acquisition, consolidation, and retrieval, is one of the hallmarks in AD. At the cellular level, dysregulated synaptic plasticity partly due to reduced long-term potentiation (LTP) and enhanced long-term depression (LTD) underlies the memory deficits in AD. GluA3 containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are one of key receptors involved in rapid neurotransmission and synaptic plasticity. Recent studies revealed a novel form of GluA3 involved in neuronal plasticity that is dependent on cyclic adenosine monophosphate (cAMP), rather than N-methyl-d-aspartate (NMDA). However, this cAMP-dependent GluA3 pathway is specifically and significantly impaired by amyloid beta (Aβ), a pathological marker of AD. cAMP is a key second messenger that plays an important role in modulating memory and synaptic plasticity. We previously reported that exchange protein directly activated by cAMP 2 (Epac2), acting as a main cAMP effector, plays a specific and time-limited role in memory retrieval. From electrophysiological perspective, Epac2 facilities the maintenance of LTP, a cellular event closely associated with memory retrieval. Additionally, Epac2 was found to be involved in the GluA3-mediated plasticity. In this review, we comprehensively summarize current knowledge regarding the specific roles of GluA3 and Epac2 in synaptic plasticity and memory, and their potential association with AD.
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Affiliation(s)
- Tong Zhang
- Department of Molecular Pharmacology, University of Groningen, the Netherlands; Department of Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen 9747 AG, Netherlands
| | - Amalia M Dolga
- Department of Molecular Pharmacology, University of Groningen, the Netherlands; Groningen Research Institute for Asthma and COPD, GRIAC, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Ulrich L M Eisel
- Department of Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen 9747 AG, Netherlands
| | - Martina Schmidt
- Department of Molecular Pharmacology, University of Groningen, the Netherlands; Groningen Research Institute for Asthma and COPD, GRIAC, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
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7
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Fardoun M, Nasser SA, El-Yazbi AF, Eid AH. GPER Acts Through the cAMP/Epac/JNK/AP-1 Pathway to Induce Transcription of Alpha 2C Adrenoceptor in Human Microvascular Smooth Muscle Cells. J Cardiovasc Pharmacol 2023; 82:470-479. [PMID: 37773889 DOI: 10.1097/fjc.0000000000001489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 09/17/2023] [Indexed: 10/01/2023]
Abstract
ABSTRACT Raynaud's phenomenon, which results from exaggerated cold-induced vasoconstriction, is more prevalent in females than males. We previously showed that estrogen increases the expression of alpha 2C-adrenoceptors (α 2C -AR), the sole mediator of cold-induced vasoconstriction. This effect of estrogen is reproduced by the cell-impermeable form of the hormone (E 2 :bovine serum albumin [BSA]), suggesting a role of the membrane estrogen receptor, G-protein-coupled estrogen receptor [GPER], in E 2 -induced α 2C -AR expression. We also previously reported that E 2 upregulates α 2C -AR in microvascular smooth muscle cells (VSMCs) via the cAMP/Epac/Rap/JNK/AP-1 pathway, and that E 2 :BSA elevates cAMP levels. We, therefore, hypothesized that E 2 uses GPER to upregulate α 2C -AR through the cAMP/Epac/JNK/AP-1 pathway. Our results show that G15, a selective GPER antagonist, attenuates the E 2 -induced increase in α 2C -AR transcription. G-1, a selective GPER agonist, induced α 2C -AR transcription, which was concomitant with elevated cAMP levels and JNK activation. Pretreatment with ESI09, an Epac inhibitor, abolished G-1-induced α 2C -AR upregulation and JNK activation. Moreover, pretreatment with SP600125, a JNK-specific inhibitor, but not H89, a PKA-specific inhibitor, abolished G-1-induced α 2C -AR upregulation. In addition, transient transfection of an Epac dominant negative mutant (Epac-DN) attenuated G-1-induced activation of the α 2C -AR promoter. This inhibitory effect of Epac-DN on the α 2C -AR promoter was overridden by the cotransfection of constitutively active JNK mutant. Furthermore, mutation of AP-1 site in the α 2C -AR promoter abrogated G1-induced expression. Collectively, these results indicate that GPER upregulates α 2C -AR through the cAMP/EPAC/JNK/AP-1 pathway. These findings unravel GPER as a new mediator of cold-induced vasoconstriction, and present it as a potential target for treating Raynaud's phenomenon in estrogen-replete females.
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Affiliation(s)
- Manal Fardoun
- Department of Pharmacology and Toxicology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | | | - Ahmed F El-Yazbi
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
- Faculty of Pharmacy, Alamein International University, Alamein City, Egypt; and
| | - Ali H Eid
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
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8
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Dall'Olmo L, Papa N, Surdo NC, Marigo I, Mocellin S. Alpha-melanocyte stimulating hormone (α-MSH): biology, clinical relevance and implication in melanoma. J Transl Med 2023; 21:562. [PMID: 37608347 PMCID: PMC10463388 DOI: 10.1186/s12967-023-04405-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 08/01/2023] [Indexed: 08/24/2023] Open
Abstract
Alpha-melanocyte stimulating hormone (α-MSH) and its receptor, melanocortin 1 receptor (MC1R), have been proposed as potential target for anti-cancer strategies in melanoma research, due to their tissue specific expression and involvement in melanocyte homeostasis. However, their role in prevention and treatment of melanoma is still debated and controversial. Although a large body of evidence supports α-MSH in preventing melanoma development, some preclinical findings suggest that the α-MSH downstream signalling may promote immune escape and cancer resistance to therapy. Additionally, in metastatic melanoma both MC1R and α-MSH have been reported to be overexpressed at levels much higher than normal cells. Furthermore, targeted therapy (e.g. BRAF inhibition in BRAFV600E mutant tumours) has been shown to enhance this phenomenon. Collectively, these data suggest that targeting MC1R could serve as an approach in the treatment of metastatic melanoma. In this review, we explore the molecular biology of α-MSH with particular emphasis into its tumor-related properties, whilst elaborating the experimental evidence currently available regarding the interplay between α-MSH/MC1R axis, melanoma and antitumor strategies.
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Affiliation(s)
- Luigi Dall'Olmo
- Department of Surgical Oncological and Gastroenterological Sciences, Padua University, Via Giustiniani 2, 35128, Padua, Italy.
- Istituto Oncologico Veneto IOV-IRCCS, 35128, Padua, Italy.
| | - Nicole Papa
- Istituto Oncologico Veneto IOV-IRCCS, 35128, Padua, Italy
| | - Nicoletta Concetta Surdo
- Neuroscience Institute, National Research Council of Italy (CNR), 35121, Padua, Italy
- Veneto Institute of Molecular Medicine VIMM, Foundation for Advanced Biomedical Research, 35129, Padua, Italy
| | - Ilaria Marigo
- Department of Surgical Oncological and Gastroenterological Sciences, Padua University, Via Giustiniani 2, 35128, Padua, Italy
- Istituto Oncologico Veneto IOV-IRCCS, 35128, Padua, Italy
| | - Simone Mocellin
- Department of Surgical Oncological and Gastroenterological Sciences, Padua University, Via Giustiniani 2, 35128, Padua, Italy
- Istituto Oncologico Veneto IOV-IRCCS, 35128, Padua, Italy
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9
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Veth TS, Francavilla C, Heck AJR, Altelaar M. Elucidating Fibroblast Growth Factor-Induced Kinome Dynamics Using Targeted Mass Spectrometry and Dynamic Modeling. Mol Cell Proteomics 2023; 22:100594. [PMID: 37328066 PMCID: PMC10368922 DOI: 10.1016/j.mcpro.2023.100594] [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: 02/01/2023] [Revised: 05/02/2023] [Accepted: 06/12/2023] [Indexed: 06/18/2023] Open
Abstract
Fibroblast growth factors (FGFs) are paracrine or endocrine signaling proteins that, activated by their ligands, elicit a wide range of health and disease-related processes, such as cell proliferation and the epithelial-to-mesenchymal transition. The detailed molecular pathway dynamics that coordinate these responses have remained to be determined. To elucidate these, we stimulated MCF-7 breast cancer cells with either FGF2, FGF3, FGF4, FGF10, or FGF19. Following activation of the receptor, we quantified the kinase activity dynamics of 44 kinases using a targeted mass spectrometry assay. Our system-wide kinase activity data, supplemented with (phospho)proteomics data, reveal ligand-dependent distinct pathway dynamics, elucidate the involvement of not earlier reported kinases such as MARK, and revise some of the pathway effects on biological outcomes. In addition, logic-based dynamic modeling of the kinome dynamics further verifies the biological goodness-of-fit of the predicted models and reveals BRAF-driven activation upon FGF2 treatment and ARAF-driven activation upon FGF4 treatment.
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Affiliation(s)
- Tim S Veth
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Chiara Francavilla
- Division of Molecular and Cellular Function, School of Biological Science, and Manchester Breast Centre, Manchester Cancer Research Centre, Faculty of Biology Medicine and Health (FBMH), The University of Manchester, Manchester, UK
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands.
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10
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Sartre C, Peurois F, Ley M, Kryszke MH, Zhang W, Courilleau D, Fischmeister R, Ambroise Y, Zeghouf M, Cianferani S, Ferrandez Y, Cherfils J. Membranes prime the RapGEF EPAC1 to transduce cAMP signaling. Nat Commun 2023; 14:4157. [PMID: 37438343 DOI: 10.1038/s41467-023-39894-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 06/30/2023] [Indexed: 07/14/2023] Open
Abstract
EPAC1, a cAMP-activated GEF for Rap GTPases, is a major transducer of cAMP signaling and a therapeutic target in cardiac diseases. The recent discovery that cAMP is compartmentalized in membrane-proximal nanodomains challenged the current model of EPAC1 activation in the cytosol. Here, we discover that anionic membranes are a major component of EPAC1 activation. We find that anionic membranes activate EPAC1 independently of cAMP, increase its affinity for cAMP by two orders of magnitude, and synergize with cAMP to yield maximal GEF activity. In the cell cytosol, where cAMP concentration is low, EPAC1 must thus be primed by membranes to bind cAMP. Examination of the cell-active chemical CE3F4 in this framework further reveals that it targets only fully activated EPAC1. Together, our findings reformulate previous concepts of cAMP signaling through EPAC proteins, with important implications for drug discovery.
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Affiliation(s)
- Candice Sartre
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - François Peurois
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Marie Ley
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, IPHC, CNRS UMR 7178, Infrastructure Nationale de Protéomique ProFI - FR2048, 67087, Strasbourg, France
| | - Marie-Hélène Kryszke
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Wenhua Zhang
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Delphine Courilleau
- Université Paris-Saclay, IPSIT-CIBLOT, Inserm US31, CNRS UAR3679, 91400, Orsay, France
| | | | - Yves Ambroise
- Université Paris-Saclay, CEA, Service de Chimie Bioorganique et de Marquage, 91191, Gif-sur-Yvette, France
| | - Mahel Zeghouf
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Sarah Cianferani
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, IPHC, CNRS UMR 7178, Infrastructure Nationale de Protéomique ProFI - FR2048, 67087, Strasbourg, France
| | - Yann Ferrandez
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Jacqueline Cherfils
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France.
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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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Chuan W, Yuan L, Wen J, Jianwei Z, Caiji W, Zeqi Z, Yalan L, Renlong J, Kang L, Wei L, Houguang L, Wen L, Yuehua Q, Xuanyi L. cAMP-Epac1 signaling is activated in DDAVP-induced endolymphatic hydrops of guinea pigs. Braz J Otorhinolaryngol 2023; 89:469-476. [PMID: 37116375 PMCID: PMC10165185 DOI: 10.1016/j.bjorl.2023.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 02/07/2023] [Accepted: 03/03/2023] [Indexed: 03/16/2023] Open
Abstract
OBJECTIVE To explore whether Cyclic Adenosine Monophosphate (cAMP)-Epac1 signaling is activated in 1-Desamino-8-D-arginine-Vasopressin-induced Endolymphatic Hydrops (DDAVP-induced EH) and to provide new insight for further in-depth study of DDAVP-induced EH. METHODS Eighteen healthy, red-eyed guinea pigs (36 ears) weighing 200-350 g were randomly divided into three groups: the control group, which received intraperitoneal injection of sterile saline (same volume as that in the other two groups) for 7 consecutive days; the DDAVP-7d group, which received intraperitoneal injection of 10 mg/mL/kg DDAVP for 7 consecutive days; and the DDAVP-14d group, which received intraperitoneal injection of 10 μg/mL/kg DDAVP for 14 consecutive days. After successful modeling, all animals were sacrificed, and cochlea tissues were collected to detect the mRNA and protein expression of the exchange protein directly activated by cAMP-1 and 2 (Epac1, Epac2), and Repressor Activator Protein-1 (Rap1) by Reverse Transcription (RT)-PCR and western blotting, respectively. RESULTS Compared to the control group, the relative mRNA expression of Epac1, Epac2, Rap1A, and Rap1B in the cochlea tissue of the DDAVP-7d group was significantly higher (p < 0.05), while no significant difference in Rap1 GTPase activating protein (Rap1gap) mRNA expression was found between the two groups. The relative mRNA expression of Epac1, Rap1A, Rap1B, and Rap1gap in the cochlea tissue of the DDAVP-14d group was significantly higher than that of the control group (p < 0.05), while no significant difference in Epac2 mRNA expression was found between the DDAVP-14d and control groups. Comparison between the DDAVP-14d and DDAVP-7d groups showed that the DDAVP-14d group had significantly lower Epac2 and Rap1A (p < 0.05) and higher Rap1gap (p < 0.05) mRNA expression in the cochlea tissue than that of the DDAVP-7d group, while no significant differences in Epac1 and Rap1B mRNA expression were found between the two groups. Western blotting showed that Epac1 protein expression in the cochlea tissue was the highest in the DDAVP-14d group, followed by that in the DDAVP-7d group, and was the lowest in the control group, showing significant differences between groups (p < 0.05); Rap1 protein expression in the cochlea tissue was the highest in the DDAVP-7d group, followed by the DDAVP-14d group, and was the lowest in the control group, showing significant differences between groups (p < 0.05); no significant differences in Epac2 protein expression in the cochlea tissue were found among the three groups. CONCLUSION DDAVP upregulated Epac1 protein expression in the guinea pig cochlea, leading to activation of the inner ear cAMP-Epac1 signaling pathway. This may be an important mechanism by which DDAVP regulates endolymphatic metabolism to induce EH and affect inner ear function. OXFORD CENTRE FOR EVIDENCE-BASED MEDICINE 2011 LEVELS OF EVIDENCE: Level 5.
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Affiliation(s)
- Wang Chuan
- The Suqian Clinical College of Xuzhou Medical University, Department of Otorhinolaryngology-Head and Neck Surgery, Suqian, China; Affiliated Hospital of Xuzhou Medical University, Department of Otorhinolaryngology-Head and Neck Surgery, Xuzhou, China; Xuzhou Medical University, Institute of Audiology and Balance Science, Xuzhou, China; Xuzhou Medical University, Artificial Auditory Laboratory of Jiangsu Province, Xuzhou, China
| | - Li Yuan
- Affiliated Hospital of Xuzhou Medical University, Department of Radiology, Xuzhou, China
| | - Jiang Wen
- Affiliated Hospital of Xuzhou Medical University, Department of Otorhinolaryngology-Head and Neck Surgery, Xuzhou, China; Xuzhou Medical University, Institute of Audiology and Balance Science, Xuzhou, China; Xuzhou Medical University, Artificial Auditory Laboratory of Jiangsu Province, Xuzhou, China
| | - Zeng Jianwei
- Affiliated Hospital of Xuzhou Medical University, Department of Radiology, Xuzhou, China
| | - Wang Caiji
- Affiliated Hospital of Xuzhou Medical University, Department of Otorhinolaryngology-Head and Neck Surgery, Xuzhou, China; Xuzhou Medical University, Institute of Audiology and Balance Science, Xuzhou, China; Xuzhou Medical University, Artificial Auditory Laboratory of Jiangsu Province, Xuzhou, China
| | - Zhao Zeqi
- Affiliated Hospital of Xuzhou Medical University, Department of Otorhinolaryngology-Head and Neck Surgery, Xuzhou, China; Xuzhou Medical University, Institute of Audiology and Balance Science, Xuzhou, China; Xuzhou Medical University, Artificial Auditory Laboratory of Jiangsu Province, Xuzhou, China
| | - Li Yalan
- Gulou Hospital Affiliated to Medical College of Nanjing University, Department of Otolaryngology Head and Neck Surgery, Nanjing, China
| | - Ji Renlong
- Affiliated Hospital of Xuzhou Medical University, Department of Otorhinolaryngology-Head and Neck Surgery, Xuzhou, China; Xuzhou Medical University, Institute of Audiology and Balance Science, Xuzhou, China; Xuzhou Medical University, Artificial Auditory Laboratory of Jiangsu Province, Xuzhou, China
| | - Li Kang
- Affiliated Hospital of Xuzhou Medical University, Department of Otorhinolaryngology-Head and Neck Surgery, Xuzhou, China; Xuzhou Medical University, Institute of Audiology and Balance Science, Xuzhou, China; Xuzhou Medical University, Artificial Auditory Laboratory of Jiangsu Province, Xuzhou, China
| | - Li Wei
- Fudan University, Hearing Research Key Lab of Health Ministry of China, Eye and Ear Nose and Throat Hospital, Department of Otology and Skull Base Surgery, Shanghai, China
| | - Liu Houguang
- China University of Mining and Technology, School of Mechatronic Engineering, Xuzhou, China
| | - Liu Wen
- Xuzhou Medical University, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou, China; Affiliated Hospital of Xuzhou Medical University, Department of Otorhinolaryngology-Head and Neck Surgery, Xuzhou, China
| | - Qiao Yuehua
- Affiliated Hospital of Xuzhou Medical University, Department of Otorhinolaryngology-Head and Neck Surgery, Xuzhou, China; Xuzhou Medical University, Institute of Audiology and Balance Science, Xuzhou, China; Xuzhou Medical University, Artificial Auditory Laboratory of Jiangsu Province, Xuzhou, China
| | - Li Xuanyi
- Affiliated Hospital of Xuzhou Medical University, Department of Otorhinolaryngology-Head and Neck Surgery, Xuzhou, China; Xuzhou Medical University, Institute of Audiology and Balance Science, Xuzhou, China; Xuzhou Medical University, Artificial Auditory Laboratory of Jiangsu Province, Xuzhou, China.
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Mohamed H, Shao H, Akimoto M, Darveau P, MacKinnon MR, Magolan J, Melacini G. QSAR models reveal new EPAC-selective allosteric modulators. RSC Chem Biol 2022; 3:1230-1239. [PMID: 36320893 PMCID: PMC9533425 DOI: 10.1039/d2cb00106c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/02/2022] [Indexed: 11/23/2022] Open
Abstract
Exchange proteins directly activated by cAMP (EPAC) are guanine nucleotide exchange factors for the small GTPases, Rap1 and Rap2. They regulate several physiological functions and mitigation of their activity has been suggested as a possible treatment for multiple diseases such as cardiomyopathy, diabetes, chronic pain, and cancer. Several EPAC-specific modulators have been developed, however studies that quantify their structure-activity relationships are still lacking. Here we propose a quantitative structure-activity relationship (QSAR) model for a series of EPAC-specific compounds. The model demonstrated high reproducibility and predictivity and the predictive ability of the model was tested against a series of compounds that were unknown to the model. The compound with the highest predicted affinity was validated experimentally through fluorescence-based competition assays and NMR experiments revealed its mode of binding and mechanism of action as a partial agonist. The proposed QSAR model can, therefore, serve as an effective screening tool to identify promising EPAC-selective drug leads with enhanced potency.
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Affiliation(s)
- Hebatallah Mohamed
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton Ontario L8S 4L8 Canada
| | - Hongzhao Shao
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton Ontario L8S 4L8 Canada
| | - Madoka Akimoto
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton Ontario L8S 4L8 Canada
| | - Patrick Darveau
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton Ontario L8S 4L8 Canada
| | - Marc R MacKinnon
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton Ontario L8S 4L8 Canada
| | - Jakob Magolan
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton Ontario L8S 4L8 Canada
| | - Giuseppe Melacini
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton Ontario L8S 4L8 Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton Ontario L8S 4L8 Canada
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14
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NPC transplantation rescues sci-driven cAMP/EPAC2 alterations, leading to neuroprotection and microglial modulation. Cell Mol Life Sci 2022; 79:455. [PMID: 35904607 PMCID: PMC9338125 DOI: 10.1007/s00018-022-04494-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 07/07/2022] [Accepted: 07/17/2022] [Indexed: 11/17/2022]
Abstract
Neural progenitor cell (NPC) transplantation represents a promising treatment strategy for spinal cord injury (SCI); however, the underlying therapeutic mechanisms remain incompletely understood. We demonstrate that severe spinal contusion in adult rats causes transcriptional dysregulation, which persists from early subacute to chronic stages of SCI and affects nearly 20,000 genes in total tissue extracts. Functional analysis of this dysregulated transcriptome reveals the significant downregulation of cAMP signalling components immediately after SCI, involving genes such as EPAC2 (exchange protein directly activated by cAMP), PKA, BDNF, and CAMKK2. The ectopic transplantation of spinal cord-derived NPCs at acute or subacute stages of SCI induces a significant transcriptional impact in spinal tissue, as evidenced by the normalized expression of a large proportion of SCI-affected genes. The transcriptional modulation pattern driven by NPC transplantation includes the rescued expression of cAMP signalling genes, including EPAC2. We also explore how the sustained in vivo inhibition of EPAC2 downstream signalling via the intrathecal administration of ESI-05 for 1 week impacts therapeutic mechanisms involved in the NPC-mediated treatment of SCI. NPC transplantation in SCI rats in the presence and absence of ESI-05 administration prompts increased rostral cAMP levels; however, NPC and ESI-05 treated animals exhibit a significant reduction in EPAC2 mRNA levels compared to animals receiving only NPCs treatment. Compared with transplanted animals, NPCs + ESI-05 treatment increases the scar area (as shown by GFAP staining), polarizes microglia into an inflammatory phenotype, and increases the magnitude of the gap between NeuN + cells across the lesion. Overall, our results indicate that the NPC-associated therapeutic mechanisms in the context of SCI involve the cAMP pathway, which reduces inflammation and provides a more neuropermissive environment through an EPAC2-dependent mechanism.
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15
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Absence of EPAC1 Signaling to Stabilize CFTR in Intestinal Organoids. Cells 2022; 11:cells11152295. [PMID: 35892592 PMCID: PMC9332071 DOI: 10.3390/cells11152295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 11/20/2022] Open
Abstract
The plasma membrane (PM) stability of the cystic fibrosis transmembrane conductance regulator (CFTR), the protein which when mutated causes Cystic Fibrosis (CF), relies on multiple interaction partners that connect CFTR to signaling pathways, including cAMP signaling. It was previously shown that activation of exchange protein directly activated by cAMP 1 (EPAC1) by cAMP promotes an increase in CFTR PM levels in airway epithelial cells. However, the relevance of this pathway in other tissues, particularly the intestinal tissue, remains uncharacterized. Here, we used Western blot and forskolin-induced swelling assay to demonstrate that the EPAC1 protein is not expressed in the intestinal organoid model, and consequently the EPAC1 stabilization pathway is not in place. On the other hand, using cell surface biotinylation, EPAC1-mediated stabilization of PM CFTR is observed in intestinal cell lines. These results indicate that the EPAC1 stabilization pathway also occurs in intestinal cells and is a potential target for the development of novel combinatorial therapies for treatment of CF.
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Identification of Core Allosteric Sites through Temperature- and Nucleus-Invariant Chemical Shift Covariance. Biophys J 2022; 121:2035-2045. [PMID: 35538664 DOI: 10.1016/j.bpj.2022.05.004] [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: 11/16/2021] [Revised: 04/11/2022] [Accepted: 05/04/2022] [Indexed: 11/22/2022] Open
Abstract
Allosteric regulation is essential to control biological function. In addition, allosteric sites offer a promising venue for selective drug targeting. However, accurate mapping of allosteric sites remains challenging since allostery relies on often subtle, yet functionally relevant, structural and dynamical changes. A viable approach proposed to overcome such challenge is the chemical shift covariance analysis (CHESCA). Although CHESCA offers an exhaustive map of allosteric networks, it is critical to define the core allosteric sites to be prioritized in subsequent functional studies or the design of allosteric drugs. Here we propose two new CHESCA-based methodologies, called temperature CHESCA (T-CHESCA) and CLASS-CHESCA, aimed at narrowing down allosteric maps to the core allosteric residues. Both T- and CLASS-CHESCAs rely on the invariance of core inter-residue correlations to changes in the chemical shifts of the active and inactive conformations interconverting in fast exchange. In the T-CHESCA the chemical shifts of such states are modulated through temperature changes, while in the CLASS-CHESCA through variations in the spin-active nuclei involved in pairwise correlations. The T- and CLASS-CHESCAs as well as complete-linkage CHESCA were applied to the cAMP-binding domain of the exchange protein directly activated by cAMP (EPAC), which serves as a prototypical allosteric switch. Residues consistently identified by the three CHESCA methods were found in previously identified EPAC allosteric core sites. Hence, the T-, CLASS- and CL-CHESCA provide a toolset to establish allosteric site hierarchy and triage allosteric sites to be further analyzed by mutations and functional assays. Furthermore, the core allosteric networks selectively revealed through T- and CLASS-CHESCA are expected to facilitate the mechanistic understanding of disease-related mutations and the design of selective allosteric modulators.
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17
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Tan YQ, Li J, Chen HW. Epac, a positive or negative signaling molecule in cardiovascular diseases. Pharmacotherapy 2022; 148:112726. [DOI: 10.1016/j.biopha.2022.112726] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/14/2022] [Accepted: 02/15/2022] [Indexed: 02/08/2023]
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18
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Epac activation ameliorates tubulointerstitial inflammation in diabetic nephropathy. Acta Pharmacol Sin 2022; 43:659-671. [PMID: 34103688 PMCID: PMC8888565 DOI: 10.1038/s41401-021-00689-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 04/26/2021] [Indexed: 02/05/2023] Open
Abstract
Tubulointerstitial inflammation plays an important role in the progression of diabetic nephropathy (DN), and tubular epithelial cells (TECs) are crucial promoters of the inflammatory cascade. Exchange protein activated by cAMP (Epac) has been shown to suppress the angiotensin II (Ang-II)-induced release of inflammatory cytokines in tubular cells. However, the role of Epac in TEC-mediated tubulointerstitial inflammation in DN remains unknown. We found that administering the Epac agonist 8-pCPT-2'-O-Me-cAMP (8-O-cAMP) to db/db mice inhibited tubulointerstitial inflammation characterized by macrophage infiltration and increased inflammatory cytokine release and consequently alleviated tubulointerstitial fibrosis in the kidney. Furthermore, 8-O-cAMP administration restored CCAAT/enhancer binding protein β (C/EBP-β) expression and further upregulated the expression of Suppressor of cytokine signaling 3 (SOCS3), while inhibiting p-STAT3, MCP-1, IL-6, and TNF-α expression in the kidney cortex in db/db mice. And in vitro study showed that macrophage migration and MCP-1 expression induced by high glucose (HG, 30 mM) were notably reduced by 8-O-cAMP in human renal proximal tubule epithelial (HK-2) cells. In addition, 8-O-cAMP treatment restored C/EBP-β expression in HK-2 cells and promoted C/EBP-β translocation to the nucleus, where it transcriptionally upregulated SOCS3 expression, subsequently inhibiting STAT3 phosphorylation. Under HG conditions, siRNA-mediated knockdown of C/EBP-β or SOCS3 in HK-2 cells partially blocked the inhibitory effect of Epac activation on the release of MCP-1. In contrast, SOCS3 overexpression inhibited HG-induced activation of STAT3 and MCP-1 expression in HK-2 cells. These findings indicate that Epac activation via 8-O-cAMP ameliorates tubulointerstitial inflammation in DN through the C/EBP-β/SOCS3/STAT3 pathway.
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The Role of Neuropeptide-Stimulated cAMP-EPACs Signalling in Cancer Cells. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27010311. [PMID: 35011543 PMCID: PMC8746471 DOI: 10.3390/molecules27010311] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/23/2021] [Accepted: 12/27/2021] [Indexed: 02/06/2023]
Abstract
Neuropeptides are autocrine and paracrine signalling factors and mainly bind to G protein-coupled receptors (GPCRs) to trigger intracellular secondary messenger release including adenosine 3′, 5′-cyclic monophosphate (cAMP), thus modulating cancer progress in different kind of tumours. As one of the downstream effectors of cAMP, exchange proteins directly activated by cAMP (EPACs) play dual roles in cancer proliferation and metastasis. More evidence about the relationship between neuropeptides and EPAC pathways have been proposed for their potential role in cancer development; hence, this review focuses on the role of neuropeptide/GPCR system modulation of cAMP/EPACs pathways in cancers. The correlated downstream pathways between neuropeptides and EPACs in cancer cell proliferation, migration, and metastasis is discussed to glimmer the direction of future research.
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Kukk O, Klarenbeek J, Jalink K. Time-Domain Fluorescence Lifetime Imaging of cAMP Levels with EPAC-Based FRET Sensors. Methods Mol Biol 2022; 2483:105-116. [PMID: 35286672 DOI: 10.1007/978-1-0716-2245-2_7] [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: 06/14/2023]
Abstract
Second messenger molecules in eukaryotic cells relay the signals from activated cell surface receptors to intracellular effector proteins. FRET-based sensors are ideal to visualize and measure the often rapid changes of second messenger concentrations in time and place. Fluorescence Lifetime Imaging (FLIM) is an intrinsically quantitative technique for measuring FRET. Given the recent development of commercially available, sensitive and photon-efficient FLIM instrumentation, it is becoming the method of choice for FRET detection in signaling studies. Here, we describe a detailed protocol for time domain FLIM, using the EPAC-based FRET sensor to measure changes in cellular cAMP levels with high spatiotemporal resolution as an example.
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Affiliation(s)
- Olga Kukk
- The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | | | - Kees Jalink
- The Netherlands Cancer Institute, Amsterdam, The Netherlands.
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21
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Tomilin VN, Pyrshev K, Stavniichuk A, Hassanzadeh Khayyat N, Ren G, Zaika O, Khedr S, Staruschenko A, Mei FC, Cheng X, Pochynyuk O. Epac1-/- and Epac2-/- mice exhibit deficient epithelial Na+ channel regulation and impaired urinary Na+ conservation. JCI Insight 2021; 7:145653. [PMID: 34914636 PMCID: PMC8855822 DOI: 10.1172/jci.insight.145653] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/15/2021] [Indexed: 12/03/2022] Open
Abstract
Exchange proteins directly activated by cAMP (Epacs) are abundantly expressed in the renal tubules. We used genetic and pharmacological tools in combination with balance, electrophysiological, and biochemical approaches to examine the role of Epac1 and Epac2 in renal sodium handling. We demonstrate that Epac1–/– and Epac2–/– mice exhibit a delayed anti-natriuresis to dietary sodium restriction despite augmented aldosterone levels. This was associated with a significantly lower response to the epithelial Na+ channel (ENaC) blocker amiloride, reduced ENaC activity in split-opened collecting ducts, and defective posttranslational processing of α and γENaC subunits in the KO mice fed with a Na+-deficient diet. Concomitant deletion of both isoforms led to a marginally greater natriuresis but further increased aldosterone levels. Epac2 blocker ESI-05 and Epac1&2 blocker ESI-09 decreased ENaC activity in Epac WT mice kept on the Na+-deficient diet but not on the regular diet. ESI-09 injections led to natriuresis in Epac WT mice on the Na+-deficient diet, which was caused by ENaC inhibition. In summary, our results demonstrate similar but nonredundant actions of Epac1 and Epac2 in stimulation of ENaC activity during variations in dietary salt intake. We speculate that inhibition of Epac signaling could be instrumental in treatment of hypertensive states associated with ENaC overactivation.
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Affiliation(s)
- Victor N Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Kyrylo Pyrshev
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Anna Stavniichuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Naghmeh Hassanzadeh Khayyat
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Guohui Ren
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Sherif Khedr
- Department of Physiology, Medical College of Wisconsin, Milwuakee, United States of America
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwuakee, United States of America
| | - Fang C Mei
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Xiaodong Cheng
- The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, United States of America
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22
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Duan X, Yang Y, Yang A, Zhao Y, Fan F, Niu L, Hao N. Terbutaline attenuates LPS-induced injury of pulmonary microvascular endothelial cells by cAMP/Epac signaling. Drug Dev Res 2021; 83:699-707. [PMID: 34846077 DOI: 10.1002/ddr.21901] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 11/11/2021] [Accepted: 11/22/2021] [Indexed: 11/08/2022]
Abstract
Acute lung injury (ALI), characterized by an acute onset of severe hypoxemia, is a common and devastating syndrome usually triggered by lipopolysaccharide (LPS) infection from bacteria. This study is intended to explore whether terbutaline can alleviate LPS-induced human pulmonary microvascular endothelial cell (HPMVEC) injury through cAMP/Epac signaling. LPS was utilized to induce ALI in HPMVECs, and after exposure of LPS-induced HPMVECs to terbutaline, the cellular functions including cell viability and apoptosis were measured by cell counting kit-8 and terminal deoxynucleotidyl transferase dUTP nick-end labeling. The protein expression related to cAMP/Epac signaling, apoptosis, and that of tight junction and inflammatory factors were evaluated at the same time. The effects of terbutaline on cellular functions were confirmed again after the addition of antagonists of cAMP and Epac, respectively. The levels of both cAMP and Epac reduced by LPS was concentration-dependently increased by terbutaline. The apoptosis and endothelial cell permeability damage of LPS-induced HPMVECs were enhanced after the addition of KT-5720 and ESI-09. The beneficial effects of terbutaline on alleviating the inflammation and apoptosis in HPMVECs injured by LPS are mediated by cAMP/Epac signaling, and this evidence would demonstrate the potential of terbutaline in the treatment of ALI.
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Affiliation(s)
- Xufeng Duan
- Neonatology Department, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Yingbo Yang
- Neonatology Department, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Aping Yang
- Neonatology Department, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Yan Zhao
- Neonatology Department, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Fengjuan Fan
- Neonatology Department, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Leilei Niu
- Neonatology Department, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Nan Hao
- Oncological Surgery Department, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
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23
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Lammers M. Post-translational Lysine Ac(et)ylation in Bacteria: A Biochemical, Structural, and Synthetic Biological Perspective. Front Microbiol 2021; 12:757179. [PMID: 34721364 PMCID: PMC8556138 DOI: 10.3389/fmicb.2021.757179] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/10/2021] [Indexed: 12/21/2022] Open
Abstract
Ac(et)ylation is a post-translational modification present in all domains of life. First identified in mammals in histones to regulate RNA synthesis, today it is known that is regulates fundamental cellular processes also in bacteria: transcription, translation, metabolism, cell motility. Ac(et)ylation can occur at the ε-amino group of lysine side chains or at the α-amino group of a protein. Furthermore small molecules such as polyamines and antibiotics can be acetylated and deacetylated enzymatically at amino groups. While much research focused on N-(ε)-ac(et)ylation of lysine side chains, much less is known about the occurrence, the regulation and the physiological roles on N-(α)-ac(et)ylation of protein amino termini in bacteria. Lysine ac(et)ylation was shown to affect protein function by various mechanisms ranging from quenching of the positive charge, increasing the lysine side chains’ size affecting the protein surface complementarity, increasing the hydrophobicity and by interfering with other post-translational modifications. While N-(ε)-lysine ac(et)ylation was shown to be reversible, dynamically regulated by lysine acetyltransferases and lysine deacetylases, for N-(α)-ac(et)ylation only N-terminal acetyltransferases were identified and so far no deacetylases were discovered neither in bacteria nor in mammals. To this end, N-terminal ac(et)ylation is regarded as being irreversible. Besides enzymatic ac(et)ylation, recent data showed that ac(et)ylation of lysine side chains and of the proteins N-termini can also occur non-enzymatically by the high-energy molecules acetyl-coenzyme A and acetyl-phosphate. Acetyl-phosphate is supposed to be the key molecule that drives non-enzymatic ac(et)ylation in bacteria. Non-enzymatic ac(et)ylation can occur site-specifically with both, the protein primary sequence and the three dimensional structure affecting its efficiency. Ac(et)ylation is tightly controlled by the cellular metabolic state as acetyltransferases use ac(et)yl-CoA as donor molecule for the ac(et)ylation and sirtuin deacetylases use NAD+ as co-substrate for the deac(et)ylation. Moreover, the accumulation of ac(et)yl-CoA and acetyl-phosphate is dependent on the cellular metabolic state. This constitutes a feedback control mechanism as activities of many metabolic enzymes were shown to be regulated by lysine ac(et)ylation. Our knowledge on lysine ac(et)ylation significantly increased in the last decade predominantly due to the huge methodological advances that were made in fields such as mass-spectrometry, structural biology and synthetic biology. This also includes the identification of additional acylations occurring on lysine side chains with supposedly different regulatory potential. This review highlights recent advances in the research field. Our knowledge on enzymatic regulation of lysine ac(et)ylation will be summarized with a special focus on structural and mechanistic characterization of the enzymes, the mechanisms underlying non-enzymatic/chemical ac(et)ylation are explained, recent technological progress in the field are presented and selected examples highlighting the important physiological roles of lysine ac(et)ylation are summarized.
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Affiliation(s)
- Michael Lammers
- Synthetic and Structural Biochemistry, Institute for Biochemistry, University of Greifswald, Greifswald, Germany
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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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25
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Nashine S. Potential Therapeutic Candidates for Age-Related Macular Degeneration (AMD). Cells 2021; 10:cells10092483. [PMID: 34572131 PMCID: PMC8464988 DOI: 10.3390/cells10092483] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/02/2021] [Accepted: 09/09/2021] [Indexed: 12/27/2022] Open
Abstract
Aging contributes to the risk of development of ocular diseases including, but not limited to, Age-related Macular Degeneration (AMD) that is a leading cause of blindness in the United States as well as worldwide. Retinal aging, that contributes to AMD pathogenesis, is characterized by accumulation of drusen deposits, alteration in the composition of Bruch’s membrane and extracellular matrix, vascular inflammation and dysregulation, mitochondrial dysfunction, and accumulation of reactive oxygen species (ROS), and subsequent retinal pigment epithelium (RPE) cell senescence. Since there are limited options available for the prophylaxis and treatment of AMD, new therapeutic interventions are constantly being looked into to identify new therapeutic targets for AMD. This review article discusses the potential candidates for AMD therapy and their known mechanisms of cytoprotection in AMD. These target therapeutic candidates include APE/REF-1, MRZ-99030, Ciliary NeuroTrophic Factor (CNTF), RAP1 GTPase, Celecoxib, and SS-31/Elamipretide.
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Affiliation(s)
- Sonali Nashine
- Department of Ophthalmology, University of California Irvine, Irvine, CA 92697, USA
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26
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Ruggiero D, Nutile T, Nappo S, Tirozzi A, Bellenguez C, Leutenegger AL, Ciullo M. Genetics of PlGF plasma levels highlights a role of its receptors and supports the link between angiogenesis and immunity. Sci Rep 2021; 11:16821. [PMID: 34413389 PMCID: PMC8376970 DOI: 10.1038/s41598-021-96256-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 07/28/2021] [Indexed: 11/29/2022] Open
Abstract
Placental growth factor (PlGF) is a member of the vascular endothelial growth factor family and is involved in bone marrow-derived cell activation, endothelial stimulation and pathological angiogenesis. High levels of PlGF have been observed in several pathological conditions especially in cancer, cardiovascular, autoimmune and inflammatory diseases. Little is known about the genetics of circulating PlGF levels. Indeed, although the heritability of circulating PlGF levels is around 40%, no studies have assessed the relation between PlGF plasma levels and genetic variants at a genome-wide level. In the current study, PlGF plasma levels were measured in a population-based sample of 2085 adult individuals from three isolated populations of South Italy. A GWAS was performed in a discovery cohort (N = 1600), followed by a de novo replication (N = 468) from the same populations. The meta-analysis of the discovery and replication samples revealed one signal significantly associated with PlGF circulating levels. This signal was mapped to the PlGF co-receptor coding gene NRP1, indicating its important role in modulating the PlGF plasma levels. Two additional signals, at the PlGF receptor coding gene FLT1 and RAPGEF5 gene, were identified at a suggestive level. Pathway and TWAS analyses highlighted genes known to be involved in angiogenesis and immune response, supporting the link between these processes and PlGF regulation. Overall, these data improve our understanding of the genetic variation underlying circulating PlGF levels. This in turn could lead to new preventive and therapeutic strategies for a wide variety of PlGF-related pathologies.
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Affiliation(s)
- Daniela Ruggiero
- Institute of Genetics and Biophysics "A. Buzzati-Traverso", National Research Council of Italy (CNR), Via Pietro Castellino, 111, 80131, Naples, Italy.
- IRCCS Neuromed, Pozzilli, Isernia, Italy.
| | - Teresa Nutile
- Institute of Genetics and Biophysics "A. Buzzati-Traverso", National Research Council of Italy (CNR), Via Pietro Castellino, 111, 80131, Naples, Italy
| | | | | | - Celine Bellenguez
- CHU Lille, U1167 - Labex DISTALZ - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, Inserm, Institut Pasteur de Lille, Univ. Lille, 59000, Lille, France
| | - Anne-Louise Leutenegger
- UMR 946, Genetic Variation and Human Diseases, Inserm, 75010, Paris, France
- UMR946, Université Paris-Diderot, Sorbonne Paris Cité, 75010, Paris, France
| | - Marina Ciullo
- Institute of Genetics and Biophysics "A. Buzzati-Traverso", National Research Council of Italy (CNR), Via Pietro Castellino, 111, 80131, Naples, Italy.
- IRCCS Neuromed, Pozzilli, Isernia, Italy.
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Miningou Zobon NT, Jędrzejewska-Szmek J, Blackwell KT. Temporal pattern and synergy influence activity of ERK signaling pathways during L-LTP induction. eLife 2021; 10:e64644. [PMID: 34374340 PMCID: PMC8363267 DOI: 10.7554/elife.64644] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 08/03/2021] [Indexed: 01/21/2023] Open
Abstract
Long-lasting long-term potentiation (L-LTP) is a cellular mechanism of learning and memory storage. Studies have demonstrated a requirement for extracellular signal-regulated kinase (ERK) activation in L-LTP produced by a diversity of temporal stimulation patterns. Multiple signaling pathways converge to activate ERK, with different pathways being required for different stimulation patterns. To answer whether and how different temporal patterns select different signaling pathways for ERK activation, we developed a computational model of five signaling pathways (including two novel pathways) leading to ERK activation during L-LTP induction. We show that calcium and cAMP work synergistically to activate ERK and that stimuli given with large intertrial intervals activate more ERK than shorter intervals. Furthermore, these pathways contribute to different dynamics of ERK activation. These results suggest that signaling pathways with different temporal sensitivities facilitate ERK activation to diversity of temporal patterns.
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Affiliation(s)
| | - Joanna Jędrzejewska-Szmek
- Laboratory of Neuroinformatic, Nencki Institute of Experimental Biology of Polish Academy of SciencesWarsawPoland
| | - Kim T Blackwell
- Interdisciplinary Program in Neuroscience, Bioengineering Department, George Mason UniversityFairfaxUnited States
- Krasnow Institute for Advanced Study, George Mason UniversityFairfaxUnited States
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28
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Acreman S, Zhang Q. Regulation of α-cell glucagon secretion: The role of second messengers. Chronic Dis Transl Med 2021; 8:7-18. [PMID: 35620162 PMCID: PMC9128566 DOI: 10.1016/j.cdtm.2021.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 06/15/2021] [Indexed: 11/30/2022] Open
Abstract
Glucagon is a potent glucose‐elevating hormone that is secreted by pancreatic α‐cells. While well‐controlled glucagon secretion plays an important role in maintaining systemic glucose homeostasis and preventing hypoglycaemia, it is increasingly apparent that defects in the regulation of glucagon secretion contribute to impaired counter‐regulation and hyperglycaemia in diabetes. It has therefore been proposed that pharmacological interventions targeting glucagon secretion/signalling can have great potential in improving glycaemic control of patients with diabetes. However, despite decades of research, a consensus on the precise mechanisms of glucose regulation of glucagon secretion is yet to be reached. Second messengers are a group of small intracellular molecules that relay extracellular signals to the intracellular signalling cascade, modulating cellular functions. There is a growing body of evidence that second messengers, such as cAMP and Ca2+, play critical roles in α‐cell glucose‐sensing and glucagon secretion. In this review, we discuss the impact of second messengers on α‐cell electrical activity, intracellular Ca2+ dynamics and cell exocytosis. We highlight the possibility that the interaction between different second messengers may play a key role in the glucose‐regulation of glucagon secretion.
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29
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Choi KM, Haak AJ, Diaz Espinosa AM, Cummins KA, Link PA, Aravamudhan A, Wood DK, Tschumperlin DJ. GPCR-mediated YAP/TAZ inactivation in fibroblasts via EPAC1/2, RAP2C, and MAP4K7. J Cell Physiol 2021; 236:7759-7774. [PMID: 34046891 DOI: 10.1002/jcp.30459] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 05/06/2021] [Accepted: 05/19/2021] [Indexed: 12/29/2022]
Abstract
Yes-associated protein (YAP) and PDZ-binding motif (TAZ) have emerged as important regulators of pathologic fibroblast activation in fibrotic diseases. Agonism of Gαs-coupled G protein coupled receptors (GPCRs) provides an attractive approach to inhibit the nuclear localization and function of YAP and TAZ in fibroblasts that inhibits or reverses their pathological activation. Agonism of the dopamine D1 GPCR has proven effective in preclinical models of lung and liver fibrosis. However, the molecular mechanisms coupling GPCR agonism to YAP and TAZ inactivation in fibroblasts remain incompletely understood. Here, using human lung fibroblasts, we identify critical roles for the cAMP effectors EPAC1/2, the small GTPase RAP2c, and the serine/threonine kinase MAP4K7 as the essential elements in the downstream signaling cascade linking GPCR agonism to LATS1/2-mediated YAP and TAZ phosphorylation and nuclear exclusion in fibroblasts. We further show that this EPAC/RAP2c/MAP4K7 signaling cascade is essential to the effects of dopamine D1 receptor agonism on reducing fibroblast proliferation, contraction, and extracellular matrix production. Targeted modulation of this cascade in fibroblasts may prove a useful strategy to regulate YAP and TAZ signaling and fibroblast activities central to tissue repair and fibrosis.
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Affiliation(s)
- Kyoung Moo Choi
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Andrew J Haak
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Ana M Diaz Espinosa
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Katherine A Cummins
- Department of Biomedical Engineering, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA
| | - Patrick A Link
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Aja Aravamudhan
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - David K Wood
- Department of Biomedical Engineering, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA
| | - Daniel J Tschumperlin
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
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30
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Zhang Q, Fan Z, Xue W, Sun F, Zhu H, Huang D, Wang Z, Dong L. Vitexin regulates Epac and NLRP3 and ameliorates chronic cerebral hypoperfusion injury. Can J Physiol Pharmacol 2021; 99:1079-1087. [PMID: 33915055 DOI: 10.1139/cjpp-2021-0034] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Chronic cerebral hypoperfusion (CCH), as a critical factor of chronic cerebrovascular diseases, has greatly influenced the health of patients with vascular dementia. Vitexin, a flavone C-glycoside (apigenin-8-C-β-D-glucopyranoside) that belongs to the flavone subclass of flavonoids, has been shown to possess antioxidant and anti-ischemic properties; however, the putative protective effects of vitexin on the CCH need further investigation. In the current study, the role of vitexin and its underlying mechanism were investigated with permanent bilateral common carotid artery occlusion (2VO) in rats as well as mouse hippocampal neuronal (HT22) cells with oxygen and glucose deprivation/reoxygenation (OGD/R) injury model. The results demonstrated that vitexin improved cognitive dysfunction as well as alleviated pathological neuronal damage in hematoxylin plus eosin (HE) and TUNEL results. The decreased levels of exchange protein directly activated by cAMP 1 (Epac1), Epac2, Ras-associated protein 1 (Rap1), and phospho-extracellular signal-regulated kinase (p-ERK) were reversed by vitexin in rats with CCH. Furthermore, this study indicated that vitexin alleviated CCH-induced inflammation injuries by reducing the expression of NOD-like receptor 3 (NLRP3), caspase-1, interleukin 1β (IL-1β), IL-6, and cleaved caspase-3. In vitro, vitexin increased the expression of Epac1 and Epac2, decreased the activation of the NLRP3-mediated inflammation, and improved cell viability. Taken together, our findings suggest that vitexin can reduce the degree of the progressing pathological damage in the cortex and hippocampus and inhibit further deterioration of cognitive function in rats with CCH. Epac and NLRP3 can be regulated by vitexin in vivo and in vitro, which provides enlightenment for the protection of CCH injury.
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Affiliation(s)
- Qilong Zhang
- Department of Pharmacology, Key Laboratory of Anti-Inflammatory and Immunopharmacology of Ministry of Education, Key Laboratory of Chinese Medicine Research and Development of State Administration of Traditional Chinese Medicine, Anhui Medical University, Hefei, Anhui, China
| | - Zhijia Fan
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Wei Xue
- Department of Pharmacology, Key Laboratory of Anti-Inflammatory and Immunopharmacology of Ministry of Education, Key Laboratory of Chinese Medicine Research and Development of State Administration of Traditional Chinese Medicine, Anhui Medical University, Hefei, Anhui, China
| | - Fanfan Sun
- Department of Pharmacology, Key Laboratory of Anti-Inflammatory and Immunopharmacology of Ministry of Education, Key Laboratory of Chinese Medicine Research and Development of State Administration of Traditional Chinese Medicine, Anhui Medical University, Hefei, Anhui, China
| | - Huaqing Zhu
- Laboratory of Molecular Biology and Department of Biochemistry, Anhui Medical University, Hefei, Anhui, China
| | - Dake Huang
- Synthetic Laboratory of School of Basic Medicine Sciences, Anhui Medical University, Hefei, Anhui, China
| | - Zhicheng Wang
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Liuyi Dong
- Department of Pharmacology, Key Laboratory of Anti-Inflammatory and Immunopharmacology of Ministry of Education, Key Laboratory of Chinese Medicine Research and Development of State Administration of Traditional Chinese Medicine, Anhui Medical University, Hefei, Anhui, China
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31
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Sun F, Zhang J, Chen L, Yuan Y, Guo X, Dong L, Sun J. Epac1 Signaling Pathway Mediates the Damage and Apoptosis of Inner Ear Hair Cells after Noise Exposure in a Rat Model. Neuroscience 2021; 465:116-127. [PMID: 33838290 DOI: 10.1016/j.neuroscience.2021.03.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/12/2021] [Accepted: 03/26/2021] [Indexed: 01/21/2023]
Abstract
To investigate the role of the exchange protein directly activated by cAMP (Epac) signaling pathway in inner ear hair cell damage and apoptosis after noise exposure, we analyzed the expression level of Epac1 in a rat model of noise-induced hearing loss (NIHL), based on rat exposure to a 4-kHz and 106-dB sound pressure level (SPL) for 8 h. Loss of outer hair cells (OHCs), mitochondrial lesions, and hearing loss were examined after treatment with the Epac agonist, 8-CPT, or the Epac inhibitor, ESI-09. The effects of 8-CPT and ESI-09 on cell proliferation and apoptosis were examined by CCK-8 assays, holographic microscopy imaging, and Annexin-V FITC/PI staining in HEI-OC1 cells. The effects of 8-CPT and ESI-09 on Ca2+ entry were evaluated by confocal Ca2+ fluorescence measurement. We found that the expression level of Epac1 was significantly increased in the cochlear tissue after noise exposure. In NIHL rats, 8-CPT increased the loss of OHCs, mitochondrial lesions, and hearing loss compared to control rats, while ESI-09 produced the opposite effects. Oligomycin was used to induce HEI-OC1 cell damage in vitro. In HEI-OC1 cells treated with oligomycin, 8-CPT and ESI-09 increased and reduced cell apoptosis, respectively. Moreover, 8-CPT promoted Ca2+ uptake in HEI-OC1 cells, while ESI-09 inhibited this process. In conclusion, our data provide strong evidence that the Epac1 signaling pathway mediates early pathological damage in NIHL, and that Epac1 inhibition protects from NIHL, identifying Epac1 as a new potential therapeutic target for NIHL.
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Affiliation(s)
- Fanfan Sun
- Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of USTC, Hefei 230001, China; Department of Pharmacology, Key Laboratory of Anti-Inflammatory and Immunopharmacology of Ministry of Education, Key Laboratory of Chinese Medicine Research and Development of State Administration of Traditional Chinese Medicine, Anhui Medical University, Hefei 230032, China
| | - Junge Zhang
- Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of USTC, Hefei 230001, China
| | - Li Chen
- Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of USTC, Hefei 230001, China
| | - Yuhao Yuan
- Department of Pharmacology, Key Laboratory of Anti-Inflammatory and Immunopharmacology of Ministry of Education, Key Laboratory of Chinese Medicine Research and Development of State Administration of Traditional Chinese Medicine, Anhui Medical University, Hefei 230032, China
| | - Xiaotao Guo
- Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of USTC, Hefei 230001, China
| | - Liuyi Dong
- Department of Pharmacology, Key Laboratory of Anti-Inflammatory and Immunopharmacology of Ministry of Education, Key Laboratory of Chinese Medicine Research and Development of State Administration of Traditional Chinese Medicine, Anhui Medical University, Hefei 230032, China.
| | - Jiaqiang Sun
- Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of USTC, Hefei 230001, China.
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32
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Abstract
The well-known second messenger cyclic adenosine monophosphate (cAMP) regulates the morphology and physiology of neurons and thus higher cognitive brain functions. The discovery of exchange protein activated by cAMP (Epac) as a guanine nucleotide exchange factor for Rap GTPases has shed light on protein kinase A (PKA)-independent functions of cAMP signaling in neural tissues. Studies of cAMP-Epac-mediated signaling in neurons under normal and disease conditions also revealed its diverse contributions to neurodevelopment, synaptic remodeling, and neurotransmitter release, as well as learning, memory, and emotion. In this mini-review, the various roles of Epac isoforms, including Epac1 and Epac2, highly expressed in neural tissues are summarized, and controversies or issues are highlighted that need to be resolved to uncover the critical functions of Epac in neural tissues and the potential for a new therapeutic target of mental disorders.
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Affiliation(s)
- Kyungmin Lee
- Laboratory for Behavioral Neural Circuitry and Physiology, Department of Anatomy, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, Daegu 41944, Korea
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Abstract
The field of cAMP signaling is witnessing exciting developments with the recognition that cAMP is compartmentalized and that spatial regulation of cAMP is critical for faithful signal coding. This realization has changed our understanding of cAMP signaling from a model in which cAMP connects a receptor at the plasma membrane to an intracellular effector in a linear pathway to a model in which cAMP signals propagate within a complex network of alternative branches and the specific functional outcome strictly depends on local regulation of cAMP levels and on selective activation of a limited number of branches within the network. In this review, we cover some of the early studies and summarize more recent evidence supporting the model of compartmentalized cAMP signaling, and we discuss how this knowledge is starting to provide original mechanistic insight into cell physiology and a novel framework for the identification of disease mechanisms that potentially opens new avenues for therapeutic interventions. SIGNIFICANCE STATEMENT: cAMP mediates the intracellular response to multiple hormones and neurotransmitters. Signal fidelity and accurate coordination of a plethora of different cellular functions is achieved via organization of multiprotein signalosomes and cAMP compartmentalization in subcellular nanodomains. Defining the organization and regulation of subcellular cAMP nanocompartments is necessary if we want to understand the complex functional ramifications of pharmacological treatments that target G protein-coupled receptors and for generating a blueprint that can be used to develop precision medicine interventions.
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Affiliation(s)
- Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Anna Zerio
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Miguel J Lobo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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Guijarro-Belmar A, Domanski DM, Bo X, Shewan D, Huang W. The therapeutic potential of targeting exchange protein directly activated by cyclic adenosine 3',5'-monophosphate (Epac) for central nervous system trauma. Neural Regen Res 2021; 16:460-469. [PMID: 32985466 PMCID: PMC7996029 DOI: 10.4103/1673-5374.293256] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Millions of people worldwide are affected by traumatic spinal cord injury, which usually results in permanent sensorimotor disability. Damage to the spinal cord leads to a series of detrimental events including ischaemia, haemorrhage and neuroinflammation, which over time result in further neural tissue loss. Eventually, at chronic stages of traumatic spinal cord injury, the formation of a glial scar, cystic cavitation and the presence of numerous inhibitory molecules act as physical and chemical barriers to axonal regrowth. This is further hindered by a lack of intrinsic regrowth ability of adult neurons in the central nervous system. The intracellular signalling molecule, cyclic adenosine 3′,5′-monophosphate (cAMP), is known to play many important roles in the central nervous system, and elevating its levels as shown to improve axonal regeneration outcomes following traumatic spinal cord injury in animal models. However, therapies directly targeting cAMP have not found their way into the clinic, as cAMP is ubiquitously present in all cell types and its manipulation may have additional deleterious effects. A downstream effector of cAMP, exchange protein directly activated by cAMP 2 (Epac2), is mainly expressed in the adult central nervous system, and its activation has been shown to mediate the positive effects of cAMP on axonal guidance and regeneration. Recently, using ex vivo modelling of traumatic spinal cord injury, Epac2 activation was found to profoundly modulate the post-lesion environment, such as decreasing the activation of astrocytes and microglia. Pilot data with Epac2 activation also suggested functional improvement assessed by in vivo models of traumatic spinal cord injury. Therefore, targeting Epac2 in traumatic spinal cord injury could represent a novel strategy in traumatic spinal cord injury repair, and future work is needed to fully establish its therapeutic potential.
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Affiliation(s)
- Alba Guijarro-Belmar
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen; Sainsbury Wellcome Centre, University College London, London, UK
| | - Dominik Mateusz Domanski
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, UK
| | - Xuenong Bo
- Center for Neuroscience, Surgery and Trauma, Queen Mary University of London, London, UK
| | - Derryck Shewan
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, UK
| | - Wenlong Huang
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, UK
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35
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Cuddy SR, Schinlever AR, Dochnal S, Seegren PV, Suzich J, Kundu P, Downs TK, Farah M, Desai BN, Boutell C, Cliffe AR. Neuronal hyperexcitability is a DLK-dependent trigger of herpes simplex virus reactivation that can be induced by IL-1. eLife 2020; 9:e58037. [PMID: 33350386 PMCID: PMC7773336 DOI: 10.7554/elife.58037] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 12/14/2020] [Indexed: 12/12/2022] Open
Abstract
Herpes simplex virus-1 (HSV-1) establishes a latent infection in neurons and periodically reactivates to cause disease. The stimuli that trigger HSV-1 reactivation have not been fully elucidated. We demonstrate HSV-1 reactivation from latently infected mouse neurons induced by forskolin requires neuronal excitation. Stimuli that directly induce neurons to become hyperexcitable also induced HSV-1 reactivation. Forskolin-induced reactivation was dependent on the neuronal pathway of DLK/JNK activation and included an initial wave of viral gene expression that was independent of histone demethylase activity and linked to histone phosphorylation. IL-1β is released under conditions of stress, fever and UV exposure of the epidermis; all known triggers of clinical HSV reactivation. We found that IL-1β induced histone phosphorylation and increased the excitation in sympathetic neurons. Importantly, IL-1β triggered HSV-1 reactivation, which was dependent on DLK and neuronal excitability. Thus, HSV-1 co-opts an innate immune pathway resulting from IL-1 stimulation of neurons to induce reactivation.
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Affiliation(s)
- Sean R Cuddy
- Department of Microbiology, Immunology and Cancer Biology, University of VirginiaCharlottesvilleUnited States
- Neuroscience Graduate Program, University of VirginiaCharlottesvilleUnited States
| | - Austin R Schinlever
- Department of Microbiology, Immunology and Cancer Biology, University of VirginiaCharlottesvilleUnited States
| | - Sara Dochnal
- Department of Microbiology, Immunology and Cancer Biology, University of VirginiaCharlottesvilleUnited States
| | - Philip V Seegren
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
| | - Jon Suzich
- Department of Microbiology, Immunology and Cancer Biology, University of VirginiaCharlottesvilleUnited States
| | - Parijat Kundu
- Department of Microbiology, Immunology and Cancer Biology, University of VirginiaCharlottesvilleUnited States
| | - Taylor K Downs
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
| | - Mina Farah
- Department of Microbiology, Immunology and Cancer Biology, University of VirginiaCharlottesvilleUnited States
| | - Bimal N Desai
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
| | - Chris Boutell
- MRC-University of Glasgow Centre for Virus Research (CVR), Garscube CampusGlasgowUnited Kingdom
| | - Anna R Cliffe
- Department of Microbiology, Immunology and Cancer Biology, University of VirginiaCharlottesvilleUnited States
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Roh M, Lee H, Seo H, Lim CS, Park P, Choi JE, Kwak JH, Lee J, Kaang BK, McHugh TJ, Lee K. Perseverative stereotypic behavior of Epac2 KO mice in a reward-based decision making task. Neurosci Res 2020; 161:8-17. [PMID: 33007326 DOI: 10.1016/j.neures.2020.08.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/14/2020] [Accepted: 08/21/2020] [Indexed: 11/18/2022]
Abstract
Successfully navigating dynamic environments requires balancing the decision to stay at an optimal choice with that to switch to an alternative to acquire new knowledge. However, the genetic factors and cellular activity shaping this "stay or switch" action decision remains largely unidentified. Here we find that mice carrying a deletion of the exchange protein directly activated by cAMP 2 (Epac2) gene, a putative autism locus, exhibit perseverative "stay" behavior in a dynamic foraging task. Anatomical analysis found that the loss of Epac2 resulted in a significant decrease in the density of PV-expressing interneurons in the ventrolateral orbitofrontal cortex (OFC) and dorsal striatum (dSTR). Further, in vitro whole cell patch clamp recordings of PV+ GABAergic interneurons in the dSTR revealed altered neural activity in Epac2 KO mice in response to dopamine. Our findings highlight a potential role of Epac2 in structural changes and neural responses of PV-expressing GABAergic interneurons in the ventrolateral OFC and dSTR during value-based reinforcement learning and link Epac2 function to abnormal decision-making processes and perseverative behaviors seen in autism.
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Affiliation(s)
- Mootaek Roh
- Department of Anatomy, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, South Korea
| | - Hyunjung Lee
- Department of Anatomy, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, South Korea
| | - Hyunhyo Seo
- Department of Anatomy, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, South Korea
| | - Chae-Seok Lim
- School of Biological Sciences, Seoul National University, 1 Gwanangno, Gwanak-gu, Seoul 08826, South Korea; Department of Pharmacology, Wonkwang University School of Medicine, 460 Iksandae-ro, Iksan, Jeonbuk 54538, South Korea
| | - Pojeong Park
- School of Biological Sciences, Seoul National University, 1 Gwanangno, Gwanak-gu, Seoul 08826, South Korea
| | - Ja Eun Choi
- School of Biological Sciences, Seoul National University, 1 Gwanangno, Gwanak-gu, Seoul 08826, South Korea
| | - Ji-Hye Kwak
- Department of Anatomy, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, South Korea
| | - Juhyun Lee
- Department of Anatomy, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, South Korea
| | - Bong-Kiun Kaang
- School of Biological Sciences, Seoul National University, 1 Gwanangno, Gwanak-gu, Seoul 08826, South Korea
| | - Thomas J McHugh
- Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, 2-1, Hirosawa, Wako, Saitama 351-0198, Japan.
| | - Kyungmin Lee
- Department of Anatomy, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, South Korea.
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Wehbe N, Slika H, Mesmar J, Nasser SA, Pintus G, Baydoun S, Badran A, Kobeissy F, Eid AH, Baydoun E. The Role of Epac in Cancer Progression. Int J Mol Sci 2020; 21:ijms21186489. [PMID: 32899451 PMCID: PMC7555121 DOI: 10.3390/ijms21186489] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/14/2022] Open
Abstract
Cancer continues to be a prime contributor to global mortality. Despite tremendous research efforts and major advances in cancer therapy, much remains to be learned about the underlying molecular mechanisms of this debilitating disease. A better understanding of the key signaling events driving the malignant phenotype of cancer cells may help identify new pharmaco-targets. Cyclic adenosine 3',5'-monophosphate (cAMP) modulates a plethora of biological processes, including those that are characteristic of malignant cells. Over the years, most cAMP-mediated actions were attributed to the activity of its effector protein kinase A (PKA). However, studies have revealed an important role for the exchange protein activated by cAMP (Epac) as another effector mediating the actions of cAMP. In cancer, Epac appears to have a dual role in regulating cellular processes that are essential for carcinogenesis. In addition, the development of Epac modulators offered new routes to further explore the role of this cAMP effector and its downstream pathways in cancer. In this review, the potentials of Epac as an attractive target in the fight against cancer are depicted. Additionally, the role of Epac in cancer progression, namely its effect on cancer cell proliferation, migration/metastasis, and apoptosis, with the possible interaction of reactive oxygen species (ROS) in these phenomena, is discussed with emphasis on the underlying mechanisms and pathways.
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Affiliation(s)
- Nadine Wehbe
- Department of Biology, American University of Beirut, P.O. Box 11-0236 Beirut, Lebanon; (N.W.); (J.M.)
| | - Hasan Slika
- Department of Pharmacology and Therapeutics, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236 Beirut, Lebanon;
| | - Joelle Mesmar
- Department of Biology, American University of Beirut, P.O. Box 11-0236 Beirut, Lebanon; (N.W.); (J.M.)
| | - Suzanne A. Nasser
- Department of Pharmacology, Beirut Arab University, P.O. Box 11-5020 Beirut, Lebanon;
| | - Gianfranco Pintus
- Department of Biomedical Sciences, University of Sharjah, P.O. Box 27272 Sharjah, UAE;
- Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43, 07100 Sassari, Italy
| | - Serine Baydoun
- Department of Radiology, American University of Beirut, P.O. Box 11-0236 Beirut, Lebanon;
| | - Adnan Badran
- Department of Basic Sciences, University of Petra, P.O. Box 961343, Amman 11196, Jordan;
| | - Firas Kobeissy
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236, Beirut, Lebanon;
| | - Ali H. Eid
- Department of Pharmacology and Therapeutics, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236 Beirut, Lebanon;
- Department of Pharmacology and Therapeutics, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236, Beirut, Lebanon
- Correspondence: (A.H.E.); (E.B.); Tel.: +961-1-350-000 (ext. 4891) (A.H.E. & E.B.)
| | - Elias Baydoun
- Department of Biology, American University of Beirut, P.O. Box 11-0236 Beirut, Lebanon; (N.W.); (J.M.)
- Correspondence: (A.H.E.); (E.B.); Tel.: +961-1-350-000 (ext. 4891) (A.H.E. & E.B.)
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Bang J, Zippin JH. Cyclic adenosine monophosphate (cAMP) signaling in melanocyte pigmentation and melanomagenesis. Pigment Cell Melanoma Res 2020; 34:28-43. [PMID: 32777162 DOI: 10.1111/pcmr.12920] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/24/2020] [Accepted: 08/07/2020] [Indexed: 12/12/2022]
Abstract
The second messenger cyclic adenosine monophosphate (cAMP) regulates numerous functions in both benign melanocytes and melanoma cells. cAMP is generated from two distinct sources, transmembrane and soluble adenylyl cyclases (tmAC and sAC, respectively), and is degraded by a family of proteins called phosphodiesterases (PDEs). cAMP signaling can be regulated in many different ways and can lead to varied effects in melanocytes. It was recently revealed that distinct cAMP signaling pathways regulate pigmentation by either altering pigment gene expression or the pH of melanosomes. In the context of melanoma, many studies report seemingly contradictory roles for cAMP in tumorigenesis. For example, cAMP signaling has been implicated in both cancer promotion and suppression, as well as both therapy resistance and sensitization. This conundrum in the field may be explained by the fact that cAMP signals in discrete microdomains and each microdomain can mediate differential cellular functions. Here, we review the role of cAMP signaling microdomains in benign melanocyte biology, focusing on pigmentation, and in melanomagenesis.
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Affiliation(s)
- Jakyung Bang
- Department of Dermatology, Joan and Sanford I. Weill Medical College of Cornell University, New York, NY, USA
| | - Jonathan H Zippin
- Department of Dermatology, Joan and Sanford I. Weill Medical College of Cornell University, New York, NY, USA
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Modeling Epac1 interactions with the allosteric inhibitor AM-001 by co-solvent molecular dynamics. J Comput Aided Mol Des 2020; 34:1171-1179. [PMID: 32700175 PMCID: PMC7533256 DOI: 10.1007/s10822-020-00332-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 07/13/2020] [Indexed: 12/13/2022]
Abstract
The exchange proteins activated by cAMP (EPAC) are implicated in a large variety of physiological processes and they are considered as promising targets for a wide range of therapeutic applications. Several recent reports provided evidence for the therapeutic effectiveness of the inhibiting EPAC1 activity cardiac diseases. In that context, we recently characterized a selective EPAC1 antagonist named AM-001. This compound was featured by a non-competitive mechanism of action but the localization of its allosteric site to EPAC1 structure has yet to be investigated. Therefore, we performed cosolvent molecular dynamics with the aim to identify a suitable allosteric binding site. Then, the docking and molecular dynamics were used to determine the binding of the AM-001 to the regions highlighted by cosolvent molecular dynamics for EPAC1. These analyses led us to the identification of a suitable allosteric AM-001 binding pocket at EPAC1. As a model validation, we also evaluated the binding poses of the available AM-001 analogues, with a different biological potency. Finally, the complex EPAC1 with AM-001 bound at the putative allosteric site was further refined by molecular dynamics. The principal component analysis led us to identify the protein motion that resulted in an inactive like conformation upon the allosteric inhibitor binding.
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40
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EPAC in Vascular Smooth Muscle Cells. Int J Mol Sci 2020; 21:ijms21145160. [PMID: 32708284 PMCID: PMC7404248 DOI: 10.3390/ijms21145160] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/09/2020] [Accepted: 07/19/2020] [Indexed: 02/07/2023] Open
Abstract
Vascular smooth muscle cells (VSMCs) are major components of blood vessels. They regulate physiological functions, such as vascular tone and blood flow. Under pathological conditions, VSMCs undergo a remodeling process known as phenotypic switching. During this process, VSMCs lose their contractility and acquire a synthetic phenotype, where they over-proliferate and migrate from the tunica media to the tunica interna, contributing to the occlusion of blood vessels. Since their discovery as effector proteins of cyclic adenosine 3′,5′-monophosphate (cAMP), exchange proteins activated by cAMP (EPACs) have been shown to play vital roles in a plethora of pathways in different cell systems. While extensive research to identify the role of EPAC in the vasculature has been conducted, much remains to be explored to resolve the reported discordance in EPAC’s effects. In this paper, we review the role of EPAC in VSMCs, namely its regulation of the vascular tone and phenotypic switching, with the likely involvement of reactive oxygen species (ROS) in the interplay between EPAC and its targets/effectors.
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41
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Cytoskeleton regulators CAPZA2 and INF2 associate with CFTR to control its plasma membrane levels under EPAC1 activation. Biochem J 2020; 477:2561-2580. [PMID: 32573649 DOI: 10.1042/bcj20200287] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/19/2020] [Accepted: 06/22/2020] [Indexed: 02/06/2023]
Abstract
Cystic Fibrosis (CF), the most common lethal autosomic recessive disorder among Caucasians, is caused by mutations in the gene encoding the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) protein, a cAMP-regulated chloride channel expressed at the apical surface of epithelial cells. Cyclic AMP regulates both CFTR channel gating through a protein kinase A (PKA)-dependent process and plasma membane (PM) stability through activation of the exchange protein directly activated by cAMP1 (EPAC1). This cAMP effector, when activated promotes the NHERF1:CFTR interaction leading to an increase in CFTR at the PM by decreasing its endocytosis. Here, we used protein interaction profiling and bioinformatic analysis to identify proteins that interact with CFTR under EPAC1 activation as possible regulators of this CFTR PM anchoring. We identified an enrichment in cytoskeleton related proteins among which we characterized CAPZA2 and INF2 as regulators of CFTR trafficking to the PM. We found that CAPZA2 promotes wt-CFTR trafficking under EPAC1 activation at the PM whereas reduction of INF2 levels leads to a similar trafficking promotion effect. These results suggest that CAPZA2 is a positive regulator and INF2 a negative one for the increase of CFTR at the PM after an increase of cAMP and concomitant EPAC1 activation. Identifying the specific interactions involving CFTR and elicited by EPAC1 activation provides novel insights into late CFTR trafficking, insertion and/or stabilization at the PM and highlighs new potential therapeutic targets to tackle CF disease.
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Xu B, Li M, Wang Y, Zhao M, Morotti S, Shi Q, Wang Q, Barbagallo F, Teoh JP, Reddy GR, Bayne EF, Liu Y, Shen A, Puglisi JL, Ge Y, Li J, Grandi E, Nieves-Cintron M, Xiang YK. GRK5 Controls SAP97-Dependent Cardiotoxic β 1 Adrenergic Receptor-CaMKII Signaling in Heart Failure. Circ Res 2020; 127:796-810. [PMID: 32507058 DOI: 10.1161/circresaha.119.316319] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RATIONALE Cardiotoxic β1 adrenergic receptor (β1AR)-CaMKII (calmodulin-dependent kinase II) signaling is a major and critical feature associated with development of heart failure. SAP97 (synapse-associated protein 97) is a multifunctional scaffold protein that binds directly to the C-terminus of β1AR and organizes a receptor signalosome. OBJECTIVE We aim to elucidate the dynamics of β1AR-SAP97 signalosome and its potential role in chronic cardiotoxic β1AR-CaMKII signaling that contributes to development of heart failure. METHODS AND RESULTS The integrity of cardiac β1AR-SAP97 complex was examined in heart failure. Cardiac-specific deletion of SAP97 was developed to examine β1AR signaling in aging mice, after chronic adrenergic stimulation, and in pressure overload hypertrophic heart failure. We show that the β1AR-SAP97 signaling complex is reduced in heart failure. Cardiac-specific deletion of SAP97 yields an aging-dependent cardiomyopathy and exacerbates cardiac dysfunction induced by chronic adrenergic stimulation and pressure overload, which are associated with elevated CaMKII activity. Loss of SAP97 promotes PKA (protein kinase A)-dependent association of β1AR with arrestin2 and CaMKII and turns on an Epac (exchange protein directly activated by cAMP)-dependent activation of CaMKII, which drives detrimental functional and structural remodeling in myocardium. Moreover, we have identified that GRK5 (G-protein receptor kinase-5) is necessary to promote agonist-induced dissociation of SAP97 from β1AR. Cardiac deletion of GRK5 prevents adrenergic-induced dissociation of β1AR-SAP97 complex and increases in CaMKII activity in hearts. CONCLUSIONS These data reveal a critical role of SAP97 in maintaining the integrity of cardiac β1AR signaling and a detrimental cardiac GRK5-CaMKII axis that can be potentially targeted in heart failure therapy. Graphical Abstract: A graphical abstract is available for this article.
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Affiliation(s)
- Bing Xu
- From the VA Northern California Health Care System, Mather, CA (B.X., Y.K.X.).,Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.)
| | - Minghui Li
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.).,Nanjing First Hospital, Nanjing Medical University, China (M.L.)
| | - Ying Wang
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.)
| | - Meimi Zhao
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.)
| | - Stefano Morotti
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.)
| | - Qian Shi
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.)
| | - Qingtong Wang
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.).,Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Hefei, China (Q.W.)
| | - Federica Barbagallo
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.)
| | - Jian-Peng Teoh
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.)
| | - Gopireddy R Reddy
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.)
| | - Elizabeth F Bayne
- Department of Chemistry, University of Wisconsin-Madison (E.F.B., Y.G.)
| | - Yongming Liu
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.).,Shuguang Hospital, Shanghai University of Traditional Medicine, China (Y.L.)
| | - Ao Shen
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.).,School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, China (A.S.)
| | - Jose L Puglisi
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.)
| | - Ying Ge
- Department of Chemistry, University of Wisconsin-Madison (E.F.B., Y.G.)
| | - Ji Li
- Department of Surgery, University of South Florida, Tampa (J.L.)
| | - Eleonora Grandi
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.)
| | - Madeline Nieves-Cintron
- Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.)
| | - Yang K Xiang
- From the VA Northern California Health Care System, Mather, CA (B.X., Y.K.X.).,Department of Pharmacology, University of California at Davis (B.X., M.L., Y.W., M.Z., S.M., Q.S., Q.W., F.B., J.-P.T., G.R.R., Y.L., A.S., J.L.P., E.G., M.N.-C., Y.K.X.)
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Itzhakov D, Nitzan Y, Breitbart H. Protein kinase A inhibition induces EPAC-dependent acrosomal exocytosis in human sperm. Asian J Androl 2020; 21:337-344. [PMID: 30632486 PMCID: PMC6628745 DOI: 10.4103/aja.aja_99_18] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
To interact with the egg, the spermatozoon must undergo several biochemical and motility modifications in the female reproductive tract, collectively called capacitation. Only capacitated sperm can undergo acrosomal exocytosis, near or on the egg, a process that allows the sperm to penetrate and fertilize the egg. In the present study, we investigated the involvement of cyclic adenosine monophosphate (cAMP)-dependent processes on acrosomal exocytosis. Inhibition of protein kinase A (PKA) at the end of capacitation induced acrosomal exocytosis. This process is cAMP-dependent; however, the addition of relatively high concentration of the membrane-permeable 8-bromo-cAMP (8Br-cAMP, 0.1 mmol l−1) analog induced significant inhibition of the acrosomal exocytosis. The induction of acrosomal exocytosis by PKA inhibition was significantly inhibited by an exchange protein directly activated by cAMP (EPAC) ESI09 inhibitor. The EPAC selective substrate activated AE at relatively low concentrations (0.02–0.1 μmol l−1), whereas higher concentrations (>5 μmol l−1) were inhibitory to the AE induced by PKA inhibition. Inhibition of PKA revealed about 50% increase in intracellular cAMP levels, conditions under which EPAC can be activated to induce the AE. Induction of AE by activating the actin severing-protein, gelsolin, which causes F-actin dispersion, was inhibited by the EPAC inhibitor. The AE induced by PKA inhibition was mediated by phospholipase C activity but not by the Ca2+-channel, CatSper. Thus, inhibition of PKA at the end of the capacitation process induced EPAC/phospholipase C-dependent acrosomal exocytosis. EPAC mediates F-actin depolymerization and/or activation of effectors downstream to F-actin breakdown that lead to acrosomal exocytosis.
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Affiliation(s)
- Diana Itzhakov
- The Mina and Everard Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Yeshayahu Nitzan
- Department of Clinical Laboratory Science, Zefat Academic College, Zefat 1320611, Israel
| | - Haim Breitbart
- The Mina and Everard Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
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Fardoun MM, Issa K, Maaliki D, Nasser SA, Baydoun E, Eid AH. Estrogen increases expression of vascular alpha 2C adrenoceptor through the cAMP/Epac/JNK/AP-1 pathway and potentiates cold-induced vasoconstriction. Vascul Pharmacol 2020; 131:106690. [PMID: 32407896 DOI: 10.1016/j.vph.2020.106690] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 05/09/2020] [Accepted: 05/10/2020] [Indexed: 11/24/2022]
Abstract
Cutaneous cold-induced vasoconstriction is a normal physiological reaction mediated by alpha 2C-adrenergic receptors (α2C-ARs) expressed in vascular smooth muscle cells (VSMCs). When this reaction is exaggerated, Raynaud's phenomenon (RP) ensues. RP is more prevalent in females compared to age-matched men. We previously established that 17-β estradiol (estrogen) upregulates α2C-ARs in human VSMCs via a cAMP/Epac/Rap pathway. We also showed that cAMP acts through JNK to increase α2C-AR expression. However, whether estrogen employs JNK to regulate α2C-AR is not investigated. Knowing that the α2C-AR promoter harbors an activator protein-1 (AP-1) binding site that can be potentially activated by JNK, we hypothesized that estrogen regulates α2C-AR expression through an Epac/JNK/AP-1 pathway. Our results show that estrogen (10-10 M) activated JNK in human VSMCs extracted from cutaneous arterioles. Pretreatment with ESI09 (10 μM; an Epac inhibitor), abolished estrogen-induced JNK activation. In addition, pre-treatment with SP600125 (3 μM; a JNK specific inhibitor) abolished estrogen-induced expression of α2C-AR. Importantly, estrogen-induced activation of α2C-AR promoter was attenuated with SP600125. Moreover, transient transfection of VSMCs with an Epac dominant negative mutant (Epac-DN) abolished estrogen-induced activation of α2C-AR promoter. However, co-transfection of constitutively active JNK mutant overrode the inhibitory effect of Epac-DN on α2C-AR promoter. Moreover, estrogen caused a concentration-dependent increase in the activity of AP-1-driven reporter construct. Mutation of AP-1 site in the α2C-AR promoter abolished its activation by estrogen. This in vitro estrogen-increased α2C-AR expression was mirrored by an increase in the ex vivo functional responsiveness of arterioles. Indeed, estrogen potentiated α2C-AR-mediated cold-induced vasoconstriction, which was abolished by SP600125. Collectively, these results indicate that estrogen upregulates α2C-AR expression via an EPAC-mediated JNK/AP-1- dependent mechanism. These results provide an insight into the mechanism by which exaggerated cold-induced vasoconstriction occurs in estrogen-replete females and identify Epac and JNK as potential targets for the treatment of RP.
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Affiliation(s)
- Manal M Fardoun
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Khodr Issa
- Department of Pharmacology and Toxicology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Dina Maaliki
- Department of Pharmacology and Toxicology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Suzanne A Nasser
- Department of Pharmacology and Therapeutics, Beirut Arab University, Beirut, Lebanon
| | - Elias Baydoun
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Ali H Eid
- Department of Pharmacology and Toxicology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon; Department of Biomedical Sciences, Qatar University, Doha, Qatar.
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Shao H, Mohamed H, Boulton S, Huang J, Wang P, Chen H, Zhou J, Luchowska-Stańska U, Jentsch NG, Armstrong AL, Magolan J, Yarwood S, Melacini G. Mechanism of Action of an EPAC1-Selective Competitive Partial Agonist. J Med Chem 2020; 63:4762-4775. [PMID: 32297742 DOI: 10.1021/acs.jmedchem.9b02151] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The exchange protein activated by cAMP (EPAC) is a promising drug target for a wide disease range, from neurodegeneration and infections to cancer and cardiovascular conditions. A novel partial agonist of the EPAC isoform 1 (EPAC1), I942, was recently discovered, but its mechanism of action remains poorly understood. Here, we utilize NMR spectroscopy to map the I942-EPAC1 interactions at atomic resolution and propose a mechanism for I942 partial agonism. We found that I942 interacts with the phosphate binding cassette (PBC) and base binding region (BBR) of EPAC1, similar to cyclic adenosine monophosphate (cAMP). These results not only reveal the molecular basis for the I942 vs cAMP mimicry and competition, but also suggest that the partial agonism of I942 arises from its ability to stabilize an inhibition-incompetent activation intermediate distinct from both active and inactive EPAC1 states. The mechanism of action of I942 may facilitate drug design for EPAC-related diseases.
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Affiliation(s)
| | | | | | | | - Pingyuan Wang
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Haiying Chen
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Jia Zhou
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Urszula Luchowska-Stańska
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh Campus, Edinburgh EH14 4AS, United Kingdom
| | | | | | | | - Stephen Yarwood
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh Campus, Edinburgh EH14 4AS, United Kingdom
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Miningou N, Blackwell KT. The road to ERK activation: Do neurons take alternate routes? Cell Signal 2020; 68:109541. [PMID: 31945453 PMCID: PMC7127974 DOI: 10.1016/j.cellsig.2020.109541] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 01/11/2020] [Accepted: 01/12/2020] [Indexed: 01/29/2023]
Abstract
The ERK cascade is a central signaling pathway that regulates a wide variety of cellular processes including proliferation, differentiation, learning and memory, development, and synaptic plasticity. A wide range of inputs travel from the membrane through different signaling pathway routes to reach activation of one set of output kinases, ERK1&2. The classical ERK activation pathway beings with growth factor activation of receptor tyrosine kinases. Numerous G-protein coupled receptors and ionotropic receptors also lead to ERK through increases in the second messengers calcium and cAMP. Though both types of pathways are present in diverse cell types, a key difference is that most stimuli to neurons, e.g. synaptic inputs, are transient, on the order of milliseconds to seconds, whereas many stimuli acting on non-neural tissue, e.g. growth factors, are longer duration. The ability to consolidate these inputs to regulate the activation of ERK in response to diverse signals raises the question of which factors influence the difference in ERK activation pathways. This review presents both experimental studies and computational models aimed at understanding the control of ERK activation and whether there are fundamental differences between neurons and other cells. Our main conclusion is that differences between cell types are quite subtle, often related to differences in expression pattern and quantity of some molecules such as Raf isoforms. In addition, the spatial location of ERK is critical, with regulation by scaffolding proteins producing differences due to colocalization of upstream molecules that may differ between neurons and other cells.
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Affiliation(s)
- Nadiatou Miningou
- Department of Chemistry and Biochemistry, George Mason University, Fairfax, VA 22030, United States of America
| | - Kim T Blackwell
- Interdisciplinary Program in Neuroscience and Bioengineering Department, George Mason University, Fairfax, VA 22030, United States of America.
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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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Richard SA. EPAC2: A new and promising protein for glioma pathogenesis and therapy. Oncol Rev 2020; 14:446. [PMID: 32395202 PMCID: PMC7204831 DOI: 10.4081/oncol.2020.446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 04/16/2020] [Indexed: 01/02/2023] Open
Abstract
Gliomas are prime brain cancers which are initiated by malignant modification of neural stem cells, progenitor cells and differentiated glial cells such as astrocyte, oligodendrocyte as well as ependymal cells. Exchange proteins directly activated by cAMP (EPACs) are crucial cyclic adenosine 3’,5’-monophosphate (cAMP)-determined signaling pathways. Cyclic AMP-intermediated signaling events were utilized to transduce protein kinase A (PKA) leading to the detection of EPACs or cAMP-guanine exchange factors (cAMP-GEFs). EPACs have been detected as crucial proteins associated with the pathogenesis of neurological disorders as well as numerous human diseases. EPAC proteins have two isoforms. These isoforms are EPAC1 and EPAC2. EPAC2 also known as Rap guanine nucleotide exchange factor 4 (RAPGEF4) is generally expression in all neurites. Higher EAPC2 levels was detected in the cortex, hippocampus as well as striatum of adult mouse brain. Activation as well as over-secretion of EPAC2 triggers apoptosis in neurons and EPAC-triggered apoptosis was intermediated via the modulation of Bcl-2 interacting member protein (BIM). EPAC2 secretory levels has proven to be more in low-grade clinical glioma than high-grade clinical glioma. This review therefore explores the effects of EPAC2/RAPGEF4 on the pathogenesis of glioma instead of EPAC1 because EPAC2 and not EPAC1 is predominately expressed in the brain. Therefore, EPAC2 is most likely to modulate glioma pathogenesis rather than EPAC1.
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Affiliation(s)
- Seidu A Richard
- Department of Medicine, Princefield University, Ho, Ghana, West Africa
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Argyrousi EK, Heckman PRA, Prickaerts J. Role of cyclic nucleotides and their downstream signaling cascades in memory function: Being at the right time at the right spot. Neurosci Biobehav Rev 2020; 113:12-38. [PMID: 32044374 DOI: 10.1016/j.neubiorev.2020.02.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 01/23/2020] [Accepted: 02/03/2020] [Indexed: 01/23/2023]
Abstract
A plethora of studies indicate the important role of cAMP and cGMP cascades in neuronal plasticity and memory function. As a result, altered cyclic nucleotide signaling has been implicated in the pathophysiology of mnemonic dysfunction encountered in several diseases. In the present review we provide a wide overview of studies regarding the involvement of cyclic nucleotides, as well as their upstream and downstream molecules, in physiological and pathological mnemonic processes. Next, we discuss the regulation of the intracellular concentration of cyclic nucleotides via phosphodiesterases, the enzymes that degrade cAMP and/or cGMP, and via A-kinase-anchoring proteins that refine signal compartmentalization of cAMP signaling. We also provide an overview of the available data pointing to the existence of specific time windows in cyclic nucleotide signaling during neuroplasticity and memory formation and the significance to target these specific time phases for improving memory formation. Finally, we highlight the importance of emerging imaging tools like Förster resonance energy transfer imaging and optogenetics in detecting, measuring and manipulating the action of cyclic nucleotide signaling cascades.
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Affiliation(s)
- Elentina K Argyrousi
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, 6200 MD, the Netherlands
| | - Pim R A Heckman
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, 6200 MD, the Netherlands
| | - Jos Prickaerts
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, 6200 MD, the Netherlands.
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50
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The Role of Cyclic AMP Signaling in Cardiac Fibrosis. Cells 2019; 9:cells9010069. [PMID: 31888098 PMCID: PMC7016856 DOI: 10.3390/cells9010069] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 12/23/2019] [Accepted: 12/24/2019] [Indexed: 12/18/2022] Open
Abstract
Myocardial stress and injury invariably promote remodeling of the cardiac tissue, which is associated with cardiomyocyte death and development of fibrosis. The fibrotic process is initially triggered by the differentiation of resident cardiac fibroblasts into myofibroblasts. These activated fibroblasts display increased proliferative capacity and secrete large amounts of extracellular matrix. Uncontrolled myofibroblast activation can thus promote heart stiffness, cardiac dysfunction, arrhythmias, and progression to heart failure. Despite the well-established role of myofibroblasts in mediating cardiac disease, our current knowledge on how signaling pathways promoting fibrosis are regulated and coordinated in this cell type is largely incomplete. In this respect, cyclic adenosine monophosphate (cAMP) signaling acts as a major modulator of fibrotic responses activated in fibroblasts of injured or stressed hearts. In particular, accumulating evidence now suggests that upstream cAMP modulators including G protein-coupled receptors, adenylyl cyclases (ACs), and phosphodiesterases (PDEs); downstream cAMP effectors such as protein kinase A (PKA) and the guanine nucleotide exchange factor Epac; and cAMP signaling organizers such as A-kinase anchoring proteins (AKAPs) modulate a variety of fundamental cellular processes involved in myocardial fibrosis including myofibroblast differentiation, proliferation, collagen secretion, and invasiveness. The current review will discuss recent advances highlighting the role of cAMP and AKAP-mediated signaling in regulating pathophysiological responses controlling cardiac fibrosis.
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