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Gao ZG, Haddad M, Jacobson KA. A 2B adenosine receptor signaling and regulation. Purinergic Signal 2024:10.1007/s11302-024-10025-y. [PMID: 38833181 DOI: 10.1007/s11302-024-10025-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 05/20/2024] [Indexed: 06/06/2024] Open
Abstract
The A2B adenosine receptor (A2BR) is one of the four adenosine-activated G protein-coupled receptors. In addition to adenosine, protein kinase C (PKC) was recently found to activate the A2BR. The A2BR is coupled to both Gs and Gi, as well as Gq proteins in some cell types. Many primary cells and cell lines, such as bladder and breast cancer, bronchial smooth muscle, skeletal muscle, and fat cells, express the A2BR endogenously at high levels, suggesting its potentially important role in asthma, cancer, diabetes, and other conditions. The A2BR has been characterized as both pro- and anti-inflammatory, inducing cell type-dependent secretion of IL-6, IL-8, and IL-10. Theophylline and enprofylline have long been used for asthma treatment, although it is still not entirely clear if their A2BR antagonism contributes to their therapeutic effects or side effects. The A2BR is required in ischemic cardiac preconditioning by adenosine. Both A2BR and protein kinase C (PKC) contribute to cardioprotection, and both modes of A2BR signaling can be blocked by A2BR antagonists. Inhibitors of PKC and A2BR are in clinical cancer trials. Sulforaphane and other isothiocyanates from cruciferous vegetables such as broccoli and cauliflower have been reported to inhibit A2BR signaling via reaction with an intracellular A2BR cysteine residue (C210). A full, A2BR-selective agonist, critical to elucidate many controversial roles of the A2BR, is still not available, although agonist-bound A2BR structures have recently been reported.
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA.
| | - Mansour Haddad
- Faculty of Pharmacy, Yarmouk University, Irbid, 21163, Jordan
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA.
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2
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Cassavaugh J, Qureshi N, Csizmadia E, Longhi MS, Matyal R, Robson SC. Regulation of Hypoxic-Adenosinergic Signaling by Estrogen: Implications for Microvascular Injury. Pharmaceuticals (Basel) 2023; 16:422. [PMID: 36986520 PMCID: PMC10059944 DOI: 10.3390/ph16030422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/02/2023] [Accepted: 03/07/2023] [Indexed: 03/14/2023] Open
Abstract
Loss of estrogen, as occurs with normal aging, leads to increased inflammation, pathologic angiogenesis, impaired mitochondrial function, and microvascular disease. While the influence of estrogens on purinergic pathways is largely unknown, extracellular adenosine, generated at high levels by CD39 and CD73, is known to be anti-inflammatory in the vasculature. To further define the cellular mechanisms necessary for vascular protection, we investigated how estrogen modulates hypoxic-adenosinergic vascular signaling responses and angiogenesis. Expression of estrogen receptors, purinergic mediators inclusive of adenosine, adenosine deaminase (ADA), and ATP were measured in human endothelial cells. Standard tube formation and wound healing assays were performed to assess angiogenesis in vitro. The impacts on purinergic responses in vivo were modeled using cardiac tissue from ovariectomized mice. CD39 and estrogen receptor alpha (ERα) levels were markedly increased in presence of estradiol (E2). Suppression of ERα resulted in decreased CD39 expression. Expression of ENT1 was decreased in an ER-dependent manner. Extracellular ATP and ADA activity levels decreased following E2 exposure while levels of adenosine increased. Phosphorylation of ERK1/2 increased following E2 treatment and was attenuated by blocking adenosine receptor (AR) and ER activity. Estradiol boosted angiogenesis, while inhibition of estrogen decreased tube formation in vitro. Expression of CD39 and phospho-ERK1/2 decreased in cardiac tissues from ovariectomized mice, whereas ENT1 expression increased with expected decreases in blood adenosine levels. Estradiol-induced upregulation of CD39 substantially increases adenosine availability, while augmenting vascular protective signaling responses. Control of CD39 by ERα follows on transcriptional regulation. These data suggest novel therapeutic avenues to explore in the amelioration of post-menopausal cardiovascular disease, by modulation of adenosinergic mechanisms.
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Affiliation(s)
- Jessica Cassavaugh
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
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3
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Pak ES, Cha JJ, Cha DR, Kanasaki K, Ha H. Adenosine receptors as emerging therapeutic targets for diabetic kidney disease. Kidney Res Clin Pract 2022; 41:S74-S88. [PMID: 36239063 PMCID: PMC9590297 DOI: 10.23876/j.krcp.22.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/27/2022] [Accepted: 05/05/2022] [Indexed: 08/07/2023] Open
Abstract
Diabetic kidney disease (DKD) is now a pandemic worldwide, and novel therapeutic options are urgently required. Adenosine, an adenosine triphosphate metabolite, plays a role in kidney homeostasis through interacting with four types of adenosine receptors (ARs): A1AR, A2AAR, A2BAR, and A3AR. Increasing evidence highlights the role of adenosine and ARs in the development and progression of DKD: 1) increased adenosine in the plasma and urine of diabetics with kidney injury, 2) increased expression of each of the ARs in diabetic kidneys, 3) the protective effect of coffee, a commonly ingested nonselective AR antagonist, on DKD, and 4) the protective effect of AR modulators in experimental DKD models. We propose AR modulators as a new therapeutic option to treat DKD. Detailed mechanistic studies on the pharmacology of AR modulators will help us to develop effective first-in-class AR modulators against DKD.
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Affiliation(s)
- Eun Seon Pak
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, Republic of Korea
| | - Jin Joo Cha
- Department of Nephrology, Korea University Ansan Hospital, Ansan, Republic of Korea
| | - Dae Ryong Cha
- Department of Nephrology, Korea University Ansan Hospital, Ansan, Republic of Korea
| | - Keizo Kanasaki
- Department of Internal Medical 1, Shimane University Faculty of Medicine, Izumo, Japan
| | - Hunjoo Ha
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, Republic of Korea
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4
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Yang W, Robichaux WG, Mei FC, Lin W, Li L, Pan S, White MA, Chen Y, Cheng X. Epac1 activation by cAMP regulates cellular SUMOylation and promotes the formation of biomolecular condensates. SCIENCE ADVANCES 2022; 8:eabm2960. [PMID: 35442725 PMCID: PMC9020664 DOI: 10.1126/sciadv.abm2960] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Protein SUMOylation plays an essential role in maintaining cellular homeostasis when cells are under stress. However, precisely how SUMOylation is regulated, and a molecular mechanism linking cellular stress to SUMOylation, remains elusive. Here, we report that cAMP, a major stress-response second messenger, acts through Epac1 as a regulator of cellular SUMOylation. The Epac1-associated proteome is highly enriched with components of the SUMOylation pathway. Activation of Epac1 by intracellular cAMP triggers phase separation and the formation of nuclear condensates containing Epac1 and general components of the SUMOylation machinery to promote cellular SUMOylation. Furthermore, genetic knockout of Epac1 obliterates oxidized low-density lipoprotein-induced cellular SUMOylation in macrophages, leading to suppression of foam cell formation. These results provide a direct nexus connecting two major cellular stress responses to define a molecular mechanism in which cAMP regulates the dynamics of cellular condensates to modulate protein SUMOylation.
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Affiliation(s)
- Wenli Yang
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, TX, USA
- Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, TX, USA
| | - William G. Robichaux
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, TX, USA
- Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, TX, USA
| | - Fang C. Mei
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, TX, USA
- Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, TX, USA
| | - Wei Lin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, TX, USA
- Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, TX, USA
| | - Li Li
- Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, TX, USA
| | - Sheng Pan
- Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, TX, USA
| | - Mark A. White
- Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX, USA
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Yuan Chen
- Department of Surgery and Moores Cancer Center, UC San Diego Health, La Jolla, CA, USA
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, TX, USA
- Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, TX, USA
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5
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Liu L, Jiang Y, Steinle J. Epac1 regulates TLR4 signaling in the diabetic retinal vasculature. Cytokine 2021; 144:155576. [PMID: 34020266 DOI: 10.1016/j.cyto.2021.155576] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/09/2021] [Accepted: 05/04/2021] [Indexed: 01/08/2023]
Abstract
Toll-like receptor 4 (TLR4) polymorphisms occur in diabetic patients. Previous work showed that TLR4 is in the retina of diabetic mice, as well as in retinal endothelial cells (REC) and Müller cells. Since we have shown that exchange protein activated by cAMP 1 (Epac1) can reduce inflammatory mediators, we hypothesized that Epac1 would inhibit TLR4 signaling. We also hypothesized that direct TLR4 inhibition would protect the diabetic retina. Human REC in normal and high glucose were treated with an Epac1 agonist to explore the actions of Epac1 on TLR4 signaling in vitro. Subsequently, 2-month diabetic endothelial cell specific knockout mice for Epac1 (Cdh5Cre-Epac1) and Epac1 floxed mice retinas were used for Western blotting for TLR4 signaling pathways. We also used direct inhibition of TLR4 via Tak242 to investigate diabetes-induced changes in retinal permeability and neuronal loss in the mice. The Epac1 agonist reduced TLR4 signaling in REC grown in high glucose. TLR4 levels and both MyD88-dependent and -independent signaling pathways are increased in Cdh5Cre-Epac1 mice compared to Epac1 floxed mice. Tak242 reduced TLR4 signaling in diabetic mice and reduced diabetes-induced increases in permeability and cell loss in the ganglion cell layer in the Epac1 floxed and Cdh5Cre-Epac1 mice. In conclusion, Epac1 reduced TLR4 signaling in the retina and in REC. Direct inhibition of TLR4 was able to protect the retina against diabetes-induced changes in permeability and cell numbers in the ganglion cell layer.
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Affiliation(s)
- Li Liu
- Department of Ophthalmology, Visual, and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Youde Jiang
- Department of Ophthalmology, Visual, and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Jena Steinle
- Department of Ophthalmology, Visual, and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48201, United States.
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Wilkat M, Bast H, Drees R, Dünser J, Mahr A, Azoitei N, Marienfeld R, Frank F, Brhel M, Ushmorov A, Greve J, Goldberg-Bockhorn E, Theodoraki MN, Doescher J, Laban S, Schuler PJ, Hoffmann TK, Brunner C. Adenosine receptor 2B activity promotes autonomous growth, migration as well as vascularization of head and neck squamous cell carcinoma cells. Int J Cancer 2020; 147:202-217. [PMID: 31846065 DOI: 10.1002/ijc.32835] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 11/21/2019] [Accepted: 12/05/2019] [Indexed: 12/18/2022]
Abstract
Adenosine is a signaling molecule that exerts dual effects on tumor growth: while it inhibits immune cell function and thereby prevents surveillance by the immune system, it influences tumorigenesis directly via activation of adenosine receptors on tumor cells at the same time. However, the adenosine-mediated mechanisms affecting oncogenic processes particularly in head and neck squamous cell carcinomas (HNSCC) are not fully understood. Here, we investigated the role of adenosine receptor activity on HNSCC-derived cell lines. Targeting the adenosine receptor A2B (ADORA2B) on these cells with the inverse agonist/antagonist PSB-603 leads to inhibition of cell proliferation, transmigration as well as VEGFA secretion in vitro. At the molecular level, these effects were associated with cell cycle arrest as well as the induction of the apoptotic pathway. In addition, shRNA-mediated downmodulation of ADORA2B expression caused decreased proliferation. Moreover, in in vivo xenograft experiments, chemical and genetic abrogation of ADORA2B activity impaired tumor growth associated with decreased tumor vascularization. Together, our findings characterize ADORA2B as a crucial player in the maintenance of HNSCC and, therefore, as a potential therapeutic target for HNSCC treatment.
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Affiliation(s)
- Max Wilkat
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Hanna Bast
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Robert Drees
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Johannes Dünser
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Amelie Mahr
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Ninel Azoitei
- Department of Internal Medicine I, Ulm University Medical Center, Ulm, Germany
| | | | - Felicia Frank
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Magnus Brhel
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Alexey Ushmorov
- Department of Physiological Chemistry, Ulm University, Ulm, Germany
| | - Jens Greve
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Eva Goldberg-Bockhorn
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Marie-Nicole Theodoraki
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Johannes Doescher
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Simon Laban
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Patrick J Schuler
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Thomas K Hoffmann
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Cornelia Brunner
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
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7
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A 2B Adenosine Receptor and Cancer. Int J Mol Sci 2019; 20:ijms20205139. [PMID: 31627281 PMCID: PMC6829478 DOI: 10.3390/ijms20205139] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/11/2019] [Accepted: 10/12/2019] [Indexed: 12/28/2022] Open
Abstract
There are four subtypes of adenosine receptors (ARs), named A1, A2A, A2B and A3, all of which are G protein-coupled receptors (GPCRs). Locally produced adenosine is a suppressant in anti-tumor immune surveillance. The A2BAR, coupled to both Gαs and Gαi G proteins, is one of the several GPCRs that are expressed in a significantly higher level in certain cancer tissues, in comparison to adjacent normal tissues. There is growing evidence that the A2BAR plays an important role in tumor cell proliferation, angiogenesis, metastasis, and immune suppression. Thus, A2BAR antagonists are novel, potentially attractive anticancer agents. Several antagonists targeting A2BAR are currently in clinical trials for various types of cancers. In this review, we first describe the signaling, agonists, and antagonists of the A2BAR. We further discuss the role of the A2BAR in the progression of various cancers, and the rationale of using A2BAR antagonists in cancer therapy.
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8
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Gonçalves DA, Silveira WA, Manfredi LH, Graça FA, Armani A, Bertaggia E, O Neill BT, Lautherbach N, Machado J, Nogara L, Pereira MG, Arcidiacono D, Realdon S, Kahn CR, Sandri M, Kettelhut IC, Navegantes LCC. Insulin/IGF1 signalling mediates the effects of β 2 -adrenergic agonist on muscle proteostasis and growth. J Cachexia Sarcopenia Muscle 2019; 10:455-475. [PMID: 30932373 PMCID: PMC6463755 DOI: 10.1002/jcsm.12395] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 12/18/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Stimulation of β2 -adrenoceptors can promote muscle hypertrophy and fibre type shift, and it can counteract atrophy and weakness. The underlying mechanisms remain elusive. METHODS Fed wild type (WT), 2-day fasted WT, muscle-specific insulin (INS) receptor (IR) knockout (M-IR-/- ), and MKR mice were studied with regard to acute effects of the β2 -agonist formoterol (FOR) on protein metabolism and signalling events. MKR mice express a dominant negative IGF1 receptor, which blocks both INS/IGF1 signalling. All received one injection of FOR (300 μg kg-1 subcutaneously) or saline. Skeletal muscles and serum samples were analysed from 30 to 240 min. For the study of chronic effects of FOR on muscle plasticity and function as well as intracellular signalling pathways, fed WT and MKR mice were treated with formoterol (300 μg kg-1 day-1 ) for 30 days. RESULTS In fed and fasted mice, one injection of FOR inhibited autophagosome formation (LC3-II content, 65%, P ≤ 0.05) that was paralleled by an increase in serum INS levels (4-fold to 25-fold, P ≤ 0.05) and the phosphorylation of Akt (4.4-fold to 6.5-fold, P ≤ 0.05) and ERK1/2 (50% to two-fold, P ≤ 0.05). This led to the suppression (40-70%, P ≤ 0.05) of the master regulators of atrophy, FoxOs, and the mRNA levels of their target genes. FOR enhanced (41%, P ≤ 0.05) protein synthesis only in fed condition and stimulated (4.4-fold to 35-fold, P ≤ 0.05) the prosynthetic Akt/mTOR/p70S6K pathway in both fed and fasted states. FOR effects on Akt signalling during fasting were blunted in both M-IR-/- and MKR mice. Inhibition of proteolysis markers by FOR was prevented only in MKR mice. Blockade of PI3K/Akt axis and mTORC1, but not ERK1/2, in fasted mice also suppressed the acute FOR effects on proteolysis and autophagy. Chronic stimulation of β2 -adrenoceptors in fed WT mice increased body (11%, P ≤ 0.05) and muscle (15%, P ≤ 0.05) growth and downregulated atrophy-related genes (30-40%, P ≤ 0.05), but these effects were abolished in MKR mice. Increases in muscle force caused by FOR (WT, 24%, P ≤ 0.05) were only partially impaired in MKR mice (12%, P ≤ 0.05), and FOR-induced slow-to-fast fibre type shift was not blocked at all in these animals. In MKR mice, FOR also restored the lower levels of muscle SDH activity to basal WT values and caused a marked reduction (57%, P ≤ 0.05) in the number of centrally nucleated fibers. CONCLUSIONS NS/IGF1 signalling is necessary for the anti-proteolytic and hypertrophic effects of in vivo β2 -adrenergic stimulation and appears to mediate FOR-induced enhancement of protein synthesis. INS/IGF1 signalling only partially contributes to gain in strength and does not mediate fibre type transition induced by FOR.
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Affiliation(s)
- Dawit A Gonçalves
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil.,Department of Biochemistry/Immunology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Wilian A Silveira
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Leandro H Manfredi
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Flávia A Graça
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Andrea Armani
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Venetian Institute of Molecular Medicine, Padova, Italy
| | - Enrico Bertaggia
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Venetian Institute of Molecular Medicine, Padova, Italy
| | - Brian T O Neill
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Natalia Lautherbach
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Juliano Machado
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Leonardo Nogara
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Venetian Institute of Molecular Medicine, Padova, Italy
| | - Marcelo G Pereira
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Diletta Arcidiacono
- Digestive Endoscopy Unit, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy
| | - Stefano Realdon
- Digestive Endoscopy Unit, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy
| | - C Ronald Kahn
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Marco Sandri
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Venetian Institute of Molecular Medicine, Padova, Italy.,Myology Center, University of Padova, Padova, Italy
| | - Isis C Kettelhut
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil.,Department of Biochemistry/Immunology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Luiz Carlos C Navegantes
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
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9
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Vecchio EA, White PJ, May LT. The adenosine A 2B G protein-coupled receptor: Recent advances and therapeutic implications. Pharmacol Ther 2019; 198:20-33. [PMID: 30677476 DOI: 10.1016/j.pharmthera.2019.01.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The adenosine A2B receptor (A2BAR) is one of four adenosine receptor subtypes belonging to the Class A family of G protein-coupled receptors (GPCRs). Until recently, the A2BAR remained poorly characterised, in part due to its relatively low affinity for the endogenous agonist adenosine and therefore presumed minor physiological significance. However, the substantial increase in extracellular adenosine concentration, the sensitisation of the receptor and the upregulation of A2BAR expression under conditions of hypoxia and inflammation, suggest the A2BAR as an exciting therapeutic target in a variety of pathological disease states. Here we discuss the pharmacology of the A2BAR and outline its role in pathophysiology including ischaemia-reperfusion injury, fibrosis, inflammation and cancer.
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Affiliation(s)
- Elizabeth A Vecchio
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia; Heart Failure Pharmacology, Baker Heart & Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Paul J White
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Lauren T May
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
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10
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Gao ZG, Inoue A, Jacobson KA. On the G protein-coupling selectivity of the native A 2B adenosine receptor. Biochem Pharmacol 2018; 151:201-213. [PMID: 29225130 PMCID: PMC5899946 DOI: 10.1016/j.bcp.2017.12.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 12/05/2017] [Indexed: 12/14/2022]
Abstract
A2B adenosine receptor (A2BAR) activation induces Gs-dependent cyclic AMP accumulation. However, A2BAR G protein-coupling to other signaling events, e.g. ERK1/2 and calcium, is not well documented. We explored Gi, Gq/11 and Gs coupling in 1321 N1 astrocytoma, HEK293, and T24 bladder cancer cells endogenously expressing human A2BAR, using NECA or nonnucleoside BAY60-6583 as agonist, selective Gi, Gs and Gq/11 blockers, and CRISPR/Cas9-based Gq- and Gs-null HEK293 cells. In HEK293 cells, A2BAR-mediated ERK1/2 activity occurred via both Gi and Gs, but not Gq/11. However, HEK293 cell calcium mobilization was completely blocked by Gq/11 inhibitor UBO-QIC and by Gq/11 knockout. In T24 cells, Gi was solely responsible for A2BAR-mediated ERK1/2 stimulation, and Gs suppressed ERK1/2 activity. A2BAR-mediated intracellular calcium mobilization in T24 cells was mainly via Gi, although Gs may also play a role, but Gq/11 is not involved. In 1321 N1 astrocytoma cells A2BAR activation suppressed rather than stimulated ERK1/2 activity. The ERK1/2 activity decrease was reversed by Gs downregulation using cholera toxin, but potentiated by Gi inhibitor pertussis toxin, and UBO-QIC had no effect. EPACs played an important role in A2BAR-mediated ERK1/2 signaling in all three cells. Thus, A2BAR may: couple to the same downstream pathway via different G proteins in different cell types; activate different downstream events via different G proteins in the same cell type; activate Gi and Gs, which have opposing or synergistic roles in different cell types/signaling pathways. The findings, relevant to drug discovery, address some reported controversial roles of A2BAR and could apply to signaling mechanisms in other GPCRs.
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.
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11
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Li Q, Teng Y, Wang J, Yu M, Li Y, Zheng H. Rap1 promotes proliferation and migration of vascular smooth muscle cell via the ERK pathway. Pathol Res Pract 2018; 214:1045-1050. [PMID: 29789158 DOI: 10.1016/j.prp.2018.04.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/29/2018] [Accepted: 04/13/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND Rap1 is involved in a multitude of cellular signal transduction pathways, which has extensively been linked to cell proliferation and migration. It has been shown to be important in the regulation of physiological and pathological processes. The present study aims to elucidate its detailed mechanistic in proliferation and migration. MATERIAL/METHODS Vascular smooth muscle cells (VSMCs) were transfected with pcDNA3.1(empty vector), pcDNA3.1 containing Myc-Tagged-Rap1V12 (Rap1V12) or pcDNA3.1 containing Flag-Tagged-Rap1GAP (Rap1GAP).The cells were presence or absence with 8CPT-2'OMe-cAMP or SDF-1 before transfection. The proliferation and migration were examined by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) and transwell analysis, respectively. Afterwards, western blot was performed to detect the expression of ERK, phosphorylated-ERK, Rap1, Rap1GAP and Rap1GTP. RESULTS The results showed that proliferation, migration and the expression of Rap1, Rap1GAP, p-EKR were boosted in treatment of Rap1V12-transfection. However, Rap1GAP presented the opposite effects. Subsequently, VSMCs were pretreatment with stimulators Rap1 guanine exchange factor (Rap1GEF), 8CPT-2'OMe-cAMP and stromal cell-derived factor 1 (SDF-1), then transfected with different vectors and the expression of Rap1, Rap1GAP and p-EKR were obviously decreased. CONCLUSIONS Taken together, these findings indicated for the first time that Rap1 was essential for the VSMCs in proliferation and migration by ERK signaling pathway.
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Affiliation(s)
- Qin Li
- Department of Vascular Surgery, Union Hospital Affiliated with Tongji Medical College of Huazhong University of Science and Technology, China
| | - Yunfei Teng
- Department of Vascular Surgery, Union Hospital Affiliated with Tongji Medical College of Huazhong University of Science and Technology, China
| | - Jian Wang
- Department of Vascular Surgery, Union Hospital Affiliated with Tongji Medical College of Huazhong University of Science and Technology, China
| | - Miao Yu
- Department of Vascular Surgery, Union Hospital Affiliated with Tongji Medical College of Huazhong University of Science and Technology, China
| | - Yiqing Li
- Department of Vascular Surgery, Union Hospital Affiliated with Tongji Medical College of Huazhong University of Science and Technology, China
| | - Hong Zheng
- Department of Vascular Surgery, Union Hospital Affiliated with Tongji Medical College of Huazhong University of Science and Technology, China.
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12
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Robichaux WG, Cheng X. Intracellular cAMP Sensor EPAC: Physiology, Pathophysiology, and Therapeutics Development. Physiol Rev 2018; 98:919-1053. [PMID: 29537337 PMCID: PMC6050347 DOI: 10.1152/physrev.00025.2017] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 12/13/2022] Open
Abstract
This review focuses on one family of the known cAMP receptors, the exchange proteins directly activated by cAMP (EPACs), also known as the cAMP-regulated guanine nucleotide exchange factors (cAMP-GEFs). Although EPAC proteins are fairly new additions to the growing list of cAMP effectors, and relatively "young" in the cAMP discovery timeline, the significance of an EPAC presence in different cell systems is extraordinary. The study of EPACs has considerably expanded the diversity and adaptive nature of cAMP signaling associated with numerous physiological and pathophysiological responses. This review comprehensively covers EPAC protein functions at the molecular, cellular, physiological, and pathophysiological levels; and in turn, the applications of employing EPAC-based biosensors as detection tools for dissecting cAMP signaling and the implications for targeting EPAC proteins for therapeutic development are also discussed.
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Affiliation(s)
- William G Robichaux
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center , Houston, Texas
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center , Houston, Texas
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13
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Giacomelli C, Daniele S, Romei C, Tavanti L, Neri T, Piano I, Celi A, Martini C, Trincavelli ML. The A 2B Adenosine Receptor Modulates the Epithelial- Mesenchymal Transition through the Balance of cAMP/PKA and MAPK/ERK Pathway Activation in Human Epithelial Lung Cells. Front Pharmacol 2018; 9:54. [PMID: 29445342 PMCID: PMC5797802 DOI: 10.3389/fphar.2018.00054] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/15/2018] [Indexed: 12/12/2022] Open
Abstract
The epithelial-mesenchymal transition (EMT) is a complex process in which cell phenotype switches from the epithelial to mesenchymal one. The deregulations of this process have been related with the occurrence of different diseases such as lung cancer and fibrosis. In the last decade, several efforts have been devoted in understanding the mechanisms that trigger and sustain this transition process. Adenosine is a purinergic signaling molecule that has been involved in the onset and progression of chronic lung diseases and cancer through the A2B adenosine receptor subtype activation, too. However, the relationship between A2BAR and EMT has not been investigated, yet. Herein, the A2BAR characterization was carried out in human epithelial lung cells. Moreover, the effects of receptor activation on EMT were investigated in the absence and presence of transforming growth factor-beta (TGF-β1), which has been known to promote the transition. The A2BAR activation alone decreased and increased the expression of epithelial markers (E-cadherin) and the mesenchymal one (Vimentin, N-cadherin), respectively, nevertheless a complete EMT was not observed. Surprisingly, the receptor activation counteracted the EMT induced by TGF-β1. Several intracellular pathways regulate the EMT: high levels of cAMP and ERK1/2 phosphorylation has been demonstrated to counteract and promote the transition, respectively. The A2BAR stimulation was able to modulated these two pathways, cAMP/PKA and MAPK/ERK, shifting the fine balance toward activation or inhibition of EMT. In fact, using a selective PKA inhibitor, which blocks the cAMP pathway, the A2BAR-mediated EMT promotion were exacerbated, and conversely the selective inhibition of MAPK/ERK counteracted the receptor-induced transition. These results highlighted the A2BAR as one of the receptors involved in the modulation of EMT process. Nevertheless, its activation is not enough to trigger a complete transition, its ability to affect different intracellular pathways could represent a mechanism at the basis of EMT maintenance/inhibition based on the extracellular microenvironment. Despite further investigations are needed, herein for the first time the A2BAR has been related to the EMT process, and therefore to the different EMT-related pathologies.
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Affiliation(s)
| | | | - Chiara Romei
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy.,Radiology Unit, University Hospital of Pisa, Pisa, Italy
| | - Laura Tavanti
- Pneumology Unit, Cardio-Thoracic Department, University Hospital of Pisa, Pisa, Italy
| | - Tommaso Neri
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy
| | - Ilaria Piano
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | - Alessandro Celi
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy
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14
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Phosri S, Bunrukchai K, Parichatikanond W, Sato VH, Mangmool S. Epac is required for exogenous and endogenous stimulation of adenosine A 2B receptor for inhibition of angiotensin II-induced collagen synthesis and myofibroblast differentiation. Purinergic Signal 2018; 14:141-156. [PMID: 29322373 DOI: 10.1007/s11302-017-9600-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/25/2017] [Indexed: 12/31/2022] Open
Abstract
Angiotensin II (Ang II) plays an important role on the pathogenesis of cardiac fibrosis. Prolong and overstimulation of angiotensin II type 1 receptor with Ang II-induced collagen synthesis and myofibroblast differentiation in cardiac fibroblasts, leading to cardiac fibrosis. Although adenosine and its analogues are known to have cardioprotective effects, the mechanistic by which adenosine A2 receptors (A2Rs) inhibit Ang II-induced cardiac fibrosis is not clearly understood. In the present study, we examined the effects of exogenous adenosine and endogenous adenosine on Ang II-induced collagen and myofibroblast differentiation determined by α-smooth muscle action (α-SMA) overexpression and their underlying signal transduction. Elevation of endogenous adenosine levels resulted in the inhibition of Ang II-induced collagen type I and III and α-SMA synthesis in cardiac fibroblasts. Moreover, treatment with exogenous adenosine which selectively stimulated A2Rs also suppressed Ang II-induced collagen synthesis and α-SMA production. These antifibrotic effects of both endogenous and exogenous adenosines are mediated through the A2B receptor (A2BR) subtype. Stimulation of A2BR exhibited antifibrotic effects via the cAMP-dependent and Epac-dependent pathways. Our results provide new mechanistic insights regarding the role for cAMP and Epac on A2BR-mediated antifibrotic effects. Thus, A2BR is one of the potential therapeutic targets against cardiac fibrosis.
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Affiliation(s)
- Sarawuth Phosri
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand
| | - Kwanchai Bunrukchai
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand
| | | | - Vilasinee H Sato
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand
| | - Supachoke Mangmool
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand.
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15
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Yang W, Mei FC, Cheng X. EPAC1 regulates endothelial annexin A2 cell surface translocation and plasminogen activation. FASEB J 2018; 32:2212-2222. [PMID: 29217666 DOI: 10.1096/fj.201701027r] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Annexins, a family of highly conserved calcium- and phospholipid-binding proteins, play important roles in a wide range of physiologic functions. Among the 12 known annexins in humans, annexin A2 (AnxA2) is one of the most extensively studied and has been implicated in various human diseases. AnxA2 can exist as a monomer or a heterotetrameric complex with S100A10 (P11) and plays a critical role in many cellular processes, including exocytosis, endocytosis, and membrane organization. At the endothelial cell surface, the (AnxA2⋅P11)2 tetramer-acting as a coreceptor for plasminogen and tissue plasminogen activator (tPA)-accelerates tPA-dependent activation of the fibrinolytic protease, plasmin, the enzyme that is responsible for thrombus dissolution and the degradation of fibrin. This study demonstrates that EPAC1 (exchange proteins directly activated by cAMP isoform 1) interacts with AnxA2 and regulates its biologic functions by modulating its membrane translocation in endothelial cells. By using genetic and pharmacologic approaches, we demonstrate that EPAC1-acting via the PLCε-PKC pathway-inhibits AnxA2 surface translocation and plasminogen activation. These results suggest that EPAC1 plays a role in the regulation of fibrinolysis in endothelial cells and may represent a novel therapeutic target for disorders of fibrinolysis.-Yang, W., Mei, F. C., Cheng, X. EPAC1 regulates endothelial annexin A2 cell surface translocation and plasminogen activation.
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Affiliation(s)
- Wenli Yang
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, USA
| | - Fang C Mei
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, USA
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, USA
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16
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Phosri S, Arieyawong A, Bunrukchai K, Parichatikanond W, Nishimura A, Nishida M, Mangmool S. Stimulation of Adenosine A 2B Receptor Inhibits Endothelin-1-Induced Cardiac Fibroblast Proliferation and α-Smooth Muscle Actin Synthesis Through the cAMP/Epac/PI3K/Akt-Signaling Pathway. Front Pharmacol 2017; 8:428. [PMID: 28713274 PMCID: PMC5492828 DOI: 10.3389/fphar.2017.00428] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 06/15/2017] [Indexed: 12/19/2022] Open
Abstract
Background and Purpose: Cardiac fibrosis is characterized by an increase in fibroblast proliferation, overproduction of extracellular matrix proteins, and the formation of myofibroblast that express α-smooth muscle actin (α-SMA). Endothelin-1 (ET-1) is involved in the pathogenesis of cardiac fibrosis. Overstimulation of endothelin receptors induced cell proliferation, collagen synthesis, and α-SMA expression in cardiac fibroblasts. Although adenosine was shown to have cardioprotective effects, the molecular mechanisms by which adenosine A2 receptor inhibit ET-1-induced fibroblast proliferation and α-SMA expression in cardiac fibroblasts are not clearly identified. Experimental Approach: This study aimed at evaluating the mechanisms of cardioprotective effects of adenosine receptor agonist in rat cardiac fibroblast by measurement of cell proliferation, and mRNA and protein levels of α-SMA. Key results: Stimulation of adenosine subtype 2B (A2B) receptor resulted in the inhibition of ET-1-induced fibroblast proliferation, and a reduction of ET-1-induced α-SMA expression that is dependent on cAMP/Epac/PI3K/Akt signaling pathways in cardiac fibroblasts. The data in this study confirm a critical role for Epac signaling on A2B receptor-mediated inhibition of ET-1-induced cardiac fibrosis via PI3K and Akt activation. Conclusion and Implications: This is the first work reporting a novel signaling pathway for the inhibition of ET-1-induced cardiac fibrosis mediated through the A2B receptor. Thus, A2B receptor agonists represent a promising perspective as therapeutic targets for the prevention of cardiac fibrosis.
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Affiliation(s)
- Sarawuth Phosri
- Department of Pharmacology, Faculty of Pharmacy, Mahidol UniversityBangkok, Thailand
| | - Ajaree Arieyawong
- Department of Pharmacology, Faculty of Pharmacy, Mahidol UniversityBangkok, Thailand
| | - Kwanchai Bunrukchai
- Department of Pharmacology, Faculty of Pharmacy, Mahidol UniversityBangkok, Thailand
| | | | - Akiyuki Nishimura
- Division of Cardiocirculatory Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural SciencesAichi, Japan
| | - Motohiro Nishida
- Division of Cardiocirculatory Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural SciencesAichi, Japan.,Department of Translational Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Kyushu UniversityFukuoka, Japan.,Precursory Research for Embryonic Science and Technology, Japan Science and Technology AgencyKawaguchi, Japan
| | - Supachoke Mangmool
- Department of Pharmacology, Faculty of Pharmacy, Mahidol UniversityBangkok, Thailand
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17
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Guinzberg R, Díaz-Cruz A, Acosta-Trujillo C, Vilchis-Landeros MM, Vázquez-Meza H, Lozano-Flores C, Chiquete-Felix N, Varela-Echavarría A, Uribe-Carvajal S, Riveros-Rosas H, Piña E. Newly synthesized cAMP is integrated at a membrane protein complex signalosome to ensure receptor response specificity. FEBS J 2016; 284:258-276. [PMID: 27865066 DOI: 10.1111/febs.13969] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 10/11/2016] [Accepted: 11/17/2016] [Indexed: 01/21/2023]
Abstract
Spatiotemporal regulation of cAMP within the cell is required to achieve receptor-specific responses. The mechanism through which the cell selects a specific response to newly synthesized cAMP is not fully understood. In hepatocyte plasma membranes, we identified two functional and independent cAMP-responsive signaling protein macrocomplexes that produce, use, degrade, and regulate their own nondiffusible (sequestered) cAMP pool to achieve their specific responses. Each complex responds to the stimulation of an adenosine G protein-coupled receptor (Ado-GPCR), bound to either A2A or A2B , but not simultaneously to both. Each isoprotein involved in each signaling cascade was identified by measuring changes in cAMP levels after receptor activation, and its participation was confirmed by antibody-mediated inactivation. A2A -Ado-GPCR selective stimulation activates adenylyl cyclase 6 (AC6), which is bound to AKAP79/150, to synthesize cAMP which is used by two other AKAP79/150-tethered proteins: protein kinase A (PKA) and phosphodiesterase 3A (PDE3A). In contrast, A2B -Ado-GPCR stimulation activates D-AKAP2-attached AC5 to generate cAMP, which is channeled to two other D-AKAP2-tethered proteins: guanine-nucleotide exchange factor 2 (Epac2) and PDE3B. In both cases, prior activation of PKA or Epac2 with selective cAMP analogs prevents de novo cAMP synthesis. In addition, we show that cAMP does not diffuse between these protein macrocomplexes or 'signalosomes'. Evidence of coimmunoprecipitation and colocalization of some proteins belonging to each signalosome is presented. Each signalosome constitutes a minimal functional signaling unit with its own machinery to synthesize and regulate a sequestered cAMP pool. Thus, each signalosome is devoted to ensure the transmission of a unique and unequivocal message through the cell.
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Affiliation(s)
- Raquel Guinzberg
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
| | - Antonio Díaz-Cruz
- Departamento de Nutrición Animal y Bioquímica, Facultad de Medicina Veterinaria y Zootécnia, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
| | - Carlos Acosta-Trujillo
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
| | | | - Héctor Vázquez-Meza
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
| | - Carlos Lozano-Flores
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, Mexico
| | - Natalia Chiquete-Felix
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
| | | | - Salvador Uribe-Carvajal
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
| | - Héctor Riveros-Rosas
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
| | - Enrique Piña
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
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18
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Sepúlveda C, Palomo I, Fuentes E. Role of adenosine A2b receptor overexpression in tumor progression. Life Sci 2016; 166:92-99. [DOI: 10.1016/j.lfs.2016.10.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 10/01/2016] [Accepted: 10/07/2016] [Indexed: 02/07/2023]
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19
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Sun Y, Huang P. Adenosine A2B Receptor: From Cell Biology to Human Diseases. Front Chem 2016; 4:37. [PMID: 27606311 PMCID: PMC4995213 DOI: 10.3389/fchem.2016.00037] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 08/11/2016] [Indexed: 12/26/2022] Open
Abstract
Extracellular adenosine is a ubiquitous signaling molecule that modulates a wide array of biological processes. Recently, significant advances have been made in our understanding of A2B adenosine receptor (A2BAR). In this review, we first summarize some of the general characteristics of A2BAR, and then we describe the multiple binding partners of the receptor, such as newly identified α-actinin-1 and p105, and discuss how these associated proteins could modulate A2BAR's functions, including certain seemingly paradoxical functions of the receptor. Growing evidence indicates a critical role of A2BAR in cancer, renal disease, and diabetes, in addition to its importance in the regulation of vascular diseases, and lung disease. Here, we also discuss the role of A2BAR in cancer, renal disease, and diabetes and the potential of the receptor as a target for treating these three diseases.
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Affiliation(s)
- Ying Sun
- Department of Biology, South University of Science and Technology of ChinaShenzhen, China; Shenzhen Key Laboratory of Cell Microenvironment, South University of Science and Technology of ChinaShenzhen, China
| | - Pingbo Huang
- Division of Life Science, Hong Kong University of Science and TechnologyHong Kong, China; Division of Biomedical Engineering, Hong Kong University of Science and TechnologyHong Kong, China; State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and TechnologyHong Kong, China
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20
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Abstract
The small G-protein Rap1 plays an important role in the regulation of endothelial barrier function, a process controlled largely by cell–cell adhesions and their connection to the actin cytoskeleton. During the various stages of barrier dynamics, different guanine nucleotide exchange factors (GEFs) control Rap1 activity, indicating that Rap1 integrates multiple input signals. Once activated, Rap1 induces numerous signaling cascades, together responsible for the increased endothelial barrier function. Most notably, Rap1 activation results in the inhibition of Rho to decrease radial stress fibers and the activation of Cdc42 to increase junctional actin. This implies that Rap regulates endothelial barrier function by dual control of cytoskeletal tension. The molecular details of the signaling pathways are becoming to be elucidated.
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Affiliation(s)
- Willem-Jan Pannekoek
- Molecular Cancer Research and Cancer Genomics Netherlands; University Medical Center Utrecht; Utrecht, The Netherlands
| | - Anneke Post
- Molecular Cancer Research and Cancer Genomics Netherlands; University Medical Center Utrecht; Utrecht, The Netherlands
| | - Johannes L Bos
- Molecular Cancer Research and Cancer Genomics Netherlands; University Medical Center Utrecht; Utrecht, The Netherlands
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21
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cAMP signalling in the vasculature: the role of Epac (exchange protein directly activated by cAMP). Biochem Soc Trans 2014; 42:89-97. [PMID: 24450633 DOI: 10.1042/bst20130253] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The second messenger cAMP plays a central role in mediating vascular smooth muscle relaxation in response to vasoactive transmitters and in strengthening endothelial cell-cell junctions that regulate the movement of solutes, cells and macromolecules between the blood and the surrounding tissue. The vasculature expresses three cAMP effector proteins: PKA (protein kinase A), CNG (cyclic-nucleotide-gated) ion channels, and the most recently discovered Epacs (exchange proteins directly activated by cAMP). Epacs are a family of GEFs (guanine-nucleotide-exchange factors) for the small Ras-related GTPases Rap1 and Rap2, and are being increasingly implicated as important mediators of cAMP signalling, both in their own right and in parallel with the prototypical cAMP target PKA. In the present paper, we review what is currently known about the role of Epac within blood vessels, particularly with regard to the regulation of vascular tone, endothelial barrier function and inflammation.
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22
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Escudero C, Roberts JM, Myatt L, Feoktistov I. Impaired adenosine-mediated angiogenesis in preeclampsia: potential implications for fetal programming. Front Pharmacol 2014; 5:134. [PMID: 24926270 PMCID: PMC4046493 DOI: 10.3389/fphar.2014.00134] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 05/16/2014] [Indexed: 01/24/2023] Open
Abstract
Preeclampsia is a pregnancy-specific syndrome, defined by such clinical hallmarks as the onset of maternal hypertension and proteinuria after 20 weeks of gestation. The syndrome is also characterized by impaired blood flow through the utero-placental circulation and relative placental ischemia, which in turn, may generate feto-placental endothelial dysfunction. Endothelial dysfunction in offspring born from preeclamptic pregnancies has been associated with an increased risk of cardiovascular disease, including hypertension, later in life. Interestingly, diminished endothelial function, manifested by low angiogenic capacity, leads to hypertension in animal studies. Recently, we have shown that the adenosine receptor A2A/nitric oxide/vascular endothelial growth factor axis is reduced in human umbilical vein endothelial cells derived from preeclamptic pregnancies, an effect correlated with gestational age at onset of preeclampsia. We and others suggested that impaired vascular function might be associated with high cardiovascular risk in offspring exposed to pregnancy diseases. However, we are not aware of any studies that examine impaired adenosine-mediated angiogenesis as a possible link to hypertension in offspring born from preeclamptic pregnancies. In this review, we present evidence supporting the hypothesis that reduced adenosine-mediated angiogenesis during preeclamptic pregnancies might be associated with development of hypertension in the offspring.
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Affiliation(s)
- Carlos Escudero
- Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis, Group of Research and Innovation in Vascular Health, Department of Basic Sciences, Faculty of Sciences, Universidad del Bío-Bío Chillán, Chile
| | - James M Roberts
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Sciences, Department of Epidemiology and Clinical and Translational Science Institute, University of Pittsburgh Pittsburgh, PA, USA
| | - Leslie Myatt
- Center for Pregnancy and Newborn Research, University of Texas Health Science Center San Antonio, TX, USA
| | - Igor Feoktistov
- Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Nashville, TN, USA ; Department of Pharmacology, School of Medicine, Vanderbilt University Nashville, TN, USA
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23
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Acurio J, Troncoso F, Bertoglia P, Salomon C, Aguayo C, Sobrevia L, Escudero C. Potential role of A2B adenosine receptors on proliferation/migration of fetal endothelium derived from preeclamptic pregnancies. BIOMED RESEARCH INTERNATIONAL 2014; 2014:274507. [PMID: 24877077 PMCID: PMC4024414 DOI: 10.1155/2014/274507] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 04/01/2014] [Indexed: 01/10/2023]
Abstract
To investigate the functionality of A2B adenosine receptor (A2BAR) and the nitric oxide (NO) and vascular endothelial growth factor (VEGF) signaling pathway in the endothelial cell proliferation/migration during preeclampsia, we used human umbilical vein endothelial cells (HUVECs) isolated from normal pregnancies (n = 15) or pregnancies with preeclampsia (n = 15). Experiments were performed in presence or absence of the nonselective adenosine receptor agonist NECA, the A2BAR selective antagonist MRS-1754, and the nitric oxide synthase (NOS) inhibitor L-NAME. Results indicated that cells from preeclampsia exhibited a significant higher protein level of A2BAR and logEC50 for NECA-mediated proliferation than normotensive pregnancies. The stimulatory effect of NECA (10 μM, 24 h) on cell proliferation was prevented by MRS-1754 (5 nM) coincubation only in cells from normotensive pregnancies. Nevertheless, L-NAME (100 μM, 24 h) reduced the NECA-induced cell proliferation/migration in HUVEC from normal pregnancy; however in preeclampsia only NECA-induced cell proliferation was reduced by L-NAME. Moreover, NECA increased protein nitration and abundance of VEGF in cells from normal pregnancy and effect prevented by MRS-1754 coincubation. Nevertheless, in preeclampsia NECA did not affect the protein level of VEGF. In conclusion HUVECs from preeclampsia exhibit elevated protein level of A2BAR and impairment of A2BAR-mediated NO/VEGF signaling pathway.
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Affiliation(s)
- Jesenia Acurio
- Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (GIANT), Group of Research and Innovation in Vascular Health (GRIVAS Health), Department of Basic Sciences, Faculty of Sciences, Universidad del Bío-Bío, Chillán, Chile
| | - Felipe Troncoso
- Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (GIANT), Group of Research and Innovation in Vascular Health (GRIVAS Health), Department of Basic Sciences, Faculty of Sciences, Universidad del Bío-Bío, Chillán, Chile
| | - Patricio Bertoglia
- Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (GIANT), Group of Research and Innovation in Vascular Health (GRIVAS Health), Department of Basic Sciences, Faculty of Sciences, Universidad del Bío-Bío, Chillán, Chile
- Obstetrics and Gynecology Department, Herminda Martin Clinical Hospital, Chillan, Chile
| | - Carlos Salomon
- University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, QLD 4006, Australia
| | - Claudio Aguayo
- Department of Clinical Biochemistry and Immunology, Faculty of Pharmacy, University of Concepción, Chile
| | - Luis Sobrevia
- University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, QLD 4006, Australia
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carlos Escudero
- Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (GIANT), Group of Research and Innovation in Vascular Health (GRIVAS Health), Department of Basic Sciences, Faculty of Sciences, Universidad del Bío-Bío, Chillán, Chile
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García-Morales V, Cuíñas A, Elíes J, Campos-Toimil M. PKA and Epac activation mediates cAMP-induced vasorelaxation by increasing endothelial NO production. Vascul Pharmacol 2014; 60:95-101. [PMID: 24469067 DOI: 10.1016/j.vph.2014.01.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 01/13/2014] [Accepted: 01/17/2014] [Indexed: 12/15/2022]
Abstract
Vascular relaxation induced by 3',5'-cyclic adenosine monophosphate (cAMP) is both endothelium-dependent and endothelium-independent, although the underlying signaling pathways are not fully understood. Aiming to uncover potential mechanisms, we performed contraction-relaxation experiments on endothelium-denuded and intact rat aorta rings and measured NO levels in isolated human endothelial cells using single cell fluorescence imaging. The vasorelaxant effect of forskolin, an adenylyl cyclase activator, was decreased after selective inhibitor of protein kinase A (PKA), a cAMP-activated kinase, or L-NAME, an endothelial nitric oxide synthase (eNOS) inhibitor, only in intact aortic rings. Both selective activation of PKA with 6-Bnz-cAMP and exchange protein directly activated by cAMP (Epac) with 8-pCPT-2'-O-Me-cAMP significantly relaxed phenylephrine-induced contractions. The vasorelaxant effect of the Epac activator, but not that of the PKA activator, was reduced by endothelium removal. Forskolin, dibutyryl cAMP (a cAMP analogue), 6-Bnz-cAMP and 8-pCPT-2'-O-Me-cAMP increased NO levels in endothelial cells and the forskolin effect was significantly inhibited by inactivation of both Epac and PKA, and eNOS inhibition. Our results indicate that the endothelium-dependent component of forskolin/cAMP-induced vasorelaxation is partially mediated by an increase in endothelial NO release due to an enhanced eNOS activity through PKA and Epac activation in endothelial cells.
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Affiliation(s)
- Verónica García-Morales
- Farmacología Cardiovascular y Plaquetaria, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Andrea Cuíñas
- Farmacología Cardiovascular y Plaquetaria, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Jacobo Elíes
- Farmacología Cardiovascular y Plaquetaria, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Manuel Campos-Toimil
- Farmacología Cardiovascular y Plaquetaria, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
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25
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Burnstock G, Ralevic V. Purinergic signaling and blood vessels in health and disease. Pharmacol Rev 2013; 66:102-92. [PMID: 24335194 DOI: 10.1124/pr.113.008029] [Citation(s) in RCA: 219] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purinergic signaling plays important roles in control of vascular tone and remodeling. There is dual control of vascular tone by ATP released as a cotransmitter with noradrenaline from perivascular sympathetic nerves to cause vasoconstriction via P2X1 receptors, whereas ATP released from endothelial cells in response to changes in blood flow (producing shear stress) or hypoxia acts on P2X and P2Y receptors on endothelial cells to produce nitric oxide and endothelium-derived hyperpolarizing factor, which dilates vessels. ATP is also released from sensory-motor nerves during antidromic reflex activity to produce relaxation of some blood vessels. In this review, we stress the differences in neural and endothelial factors in purinergic control of different blood vessels. The long-term (trophic) actions of purine and pyrimidine nucleosides and nucleotides in promoting migration and proliferation of both vascular smooth muscle and endothelial cells via P1 and P2Y receptors during angiogenesis and vessel remodeling during restenosis after angioplasty are described. The pathophysiology of blood vessels and therapeutic potential of purinergic agents in diseases, including hypertension, atherosclerosis, ischemia, thrombosis and stroke, diabetes, and migraine, is discussed.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London NW3 2PF, UK; and Department of Pharmacology, The University of Melbourne, Australia.
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26
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Ryzhov S, Biktasova A, Goldstein AE, Zhang Q, Biaggioni I, Dikov MM, Feoktistov I. Role of JunB in adenosine A2B receptor-mediated vascular endothelial growth factor production. Mol Pharmacol 2013; 85:62-73. [PMID: 24136993 DOI: 10.1124/mol.113.088567] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Interstitial adenosine stimulates neovascularization in part through A2B adenosine receptor-dependent upregulation of vascular endothelial growth factor (VEGF). In the current study, we tested the hypothesis that A2B receptors upregulate JunB, which can contribute to stimulation of VEGF production. Using the human microvascular endothelial cell line, human mast cell line, mouse cardiac Sca1-positive stromal cells, and mouse Lewis lung carcinoma (LLC) cells, we found that adenosine receptor-dependent upregulation of VEGF production was associated with an increase in VEGF transcription, activator protein-1 (AP-1) activity, and JunB accumulation in all cells investigated. Furthermore, the expression of JunB, but not the expression of other genes encoding transcription factors from the Jun family, was specifically upregulated. In LLC cells expressing A2A and A2B receptor transcripts, only the nonselective adenosine agonist NECA (5'-N-ethylcarboxamidoadenosine), but not the selective A2A receptor agonist CGS21680 [2-p-(2-carboxyethyl) phenylethylamino-5'-N-ethylcarboxamidoadenosine], significantly increased JunB reporter activity and JunB nuclear accumulation, which were inhibited by the A2B receptor antagonist PSB603 [(8-[4-[4-((4-chlorophenzyl)piperazide-1-sulfonyl)phenyl]]-1-propylxanthine]. Using activators and inhibitors of intracellular signaling, we demonstrated that A2B receptor-dependent accumulation of JunB protein and VEGF secretion share common intracellular pathways. NECA enhanced JunB binding to the murine VEGF promoter, whereas mutation of the high-affinity AP-1 site (-1093 to -1086) resulted in a loss of NECA-dependent VEGF reporter activity. Finally, NECA-dependent VEGF secretion and reporter activity were inhibited by the expression of a dominant negative JunB or by JunB knockdown. Thus, our data suggest an important role of the A2B receptor-dependent upregulation of JunB in VEGF production and possibly other AP-1-regulated events.
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Affiliation(s)
- Sergey Ryzhov
- Divisions of Cardiovascular Medicine (S.R., Q.Z., I.F.) and Clinical Pharmacology (A.E.G., I.B.), and Departments of Cancer Biology (A.B., M.M.D.), Medicine (S.R., A.E.G., Q.Z., I.B., I.F.), and Pharmacology (I.B., I.F.), Vanderbilt University, Nashville, Tennessee
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27
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Hennenberg M, Strittmatter F, Schmetkamp H, Rutz B, Walther S, Stief CG, Gratzke C. The cAMP effector EPAC activates Elk1 transcription factor in prostate smooth muscle, and is a minor regulator of α1-adrenergic contraction. J Biomed Sci 2013; 20:46. [PMID: 23815815 PMCID: PMC3712007 DOI: 10.1186/1423-0127-20-46] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 06/19/2013] [Indexed: 11/22/2022] Open
Abstract
Background Prostate smooth muscle tone is regulated by α1-adrenoceptor-induced contraction and cAMP-mediated relaxation. EPAC is an effector of cAMP, being involved in smooth muscle relaxation and cell cycle control outside the lower urinary tract. Here, we investigated the expression and function of EPAC in human prostate tissues from patients undergoing radical prostatectomy. Results mRNA and protein expression of EPAC was detected in all prostate tissues by RT-PCR and Western blot analysis. Immunoreactivity was observed in stromal cells, and colocalized with immunofluorescence for α-smooth muscle actin and calponin. Under normal conditions, noradrenaline- or phenylephrine-induced contraction of prostate strips in the organ bath was not affected by the EPAC activator pCPT (SP-8-pCPT-2′-O-Me-cAMPS.NA) (30 μM). However, when the cyclooxygenase inhibitor indomethacin (50 μM) was added, EPAC activators pCPT and OME (8-CPT-2′-O-Me-cAMP.Na) (30 μM) significantly reduced contractions by low concentrations of phenylephrine. These effects were not observed on noradrenaline-induced contraction. OME and pCPT caused phosphorylation of the transcription factor Elk1 in prostate tissues. Elk1 activation was confirmed by EMSA (electrophoretic mobility shift assay), where OME and pCPT incresed Elk1 binding to a specific DNA probe. Conclusions EPAC activation may reduce α1-adrenergic prostate contraction in the human prostate, although this effect is masked by cyclooxygenases and β-adrenoceptors. A main EPAC function in the human prostate may be the regulation of the transcription factor Elk1.
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Affiliation(s)
- Martin Hennenberg
- Department of Urology, Ludwig-Maximilians University, Munich, Germany
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28
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Evidence for a pro-proliferative feedback loop in prostate cancer: the role of Epac1 and COX-2-dependent pathways. PLoS One 2013; 8:e63150. [PMID: 23646189 PMCID: PMC3640024 DOI: 10.1371/journal.pone.0063150] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 03/29/2013] [Indexed: 12/15/2022] Open
Abstract
Objective In human prostate cancer cells, a selective Epac agonist, 8-CPT-2Me-cAMP, upregulates cell proliferation and survival via activation of Ras-MAPK and PI- 3-kinase-Akt-mTOR signaling cascades. Here we examine the role of inflammatory mediators in Epac1-induced cellular proliferation by determining the expression of the pro-inflammatory markers p-cPLA2, COX-2, and PGE2 in prostate cancer cells treated with 8-CPT-2Me-cAMP. Methods We employed inhibitors of COX-2, mTORC1, and mTORC2 to probe cyclic AMP-dependent pathways in human prostate cancer cells. RNAi targeting Epac1, Raptor, and Rictor was also employed in these studies. Results 8-CPT-2Me-cAMP treatment caused a 2–2.5-fold increase of p-cPLA2S505, COX-2, and PGE2 levels in human prostate cancer cell lines. Pretreatment of cells with the COX-2 inhibitor SC-58125 or the EP4 antagonist AH-23848, or with an inhibitor of mTORC1 and mTORC2, Torin1, significantly reduced the Epac1-dependent increase of p-cPLA2 and COX-2, p-S6-kinaseT389, and p-AKTS473. In addition, Epac1-induced protein and DNA synthesis were greatly reduced upon pretreatment of cells with either COX-2, EP4, or mTOR inhibitors. Transfection of prostate cancer cells with Epac1 dsRNA, Raptor dsRNA, or Rictor dsRNA profoundly reduced Epac1-dependent increases in p-cPLA2 and COX-2. Conclusion We show that Epac1, a downstream effector of cAMP, functions as a pro-inflammatory modulator in prostate cancer cells and promotes cell proliferation and survival by upregulating Ras-MAPK, and PI 3-kinase-Akt-mTOR signaling.
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Grandoch M, Hoffmann J, Röck K, Wenzel F, Oberhuber A, Schelzig H, Fischer JW. Novel effects of adenosine receptors on pericellular hyaluronan matrix: implications for human smooth muscle cell phenotype and interactions with monocytes during atherosclerosis. Basic Res Cardiol 2013; 108:340. [PMID: 23440385 DOI: 10.1007/s00395-013-0340-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 02/13/2013] [Accepted: 02/13/2013] [Indexed: 12/31/2022]
Abstract
Hyaluronan (HA) is responsive to pro-atherosclerotic growth factors and cytokines and is thought to contribute to neointimal hyperplasia and atherosclerosis. However, the specific function of the pericellular HA matrix is likely depend on the respective stimuli. Adenosine plays an important role in the phenotypic regulation of vascular smooth muscle cells (VSMC) and is thought to inhibit inflammatory responses during atherosclerosis. The aim of this study was to examine the regulation and function of HA matrix in response to adenosine in human coronary artery SMC (HCASMC). The adenosine receptor agonist NECA (10 μM) caused a strong induction of HA synthase (HAS)1 at 6 h and a weaker induction again after 24 h. Use of selective adenosine receptor antagonists revealed that adenosine A2(B) receptors (A2(B)R) mediate the early HAS1 induction, whereas late HAS1 induction was mediated via A2(A)R and A3R. The strong response after 6 h was mediated in part via phosphoinositide-3 kinase- and mitogen-activated protein kinase pathways and was inhibited by Epac. Functionally, NECA increased cell migration, which was abolished by shRNA-mediated knock down of HAS1. In addition to HA secretion, NECA also stimulated the formation of pronounced pericellular HA matrix in HCASMC and increased the adhesion of monocytes. The adenosine-induced monocyte adhesion was sensitive to hyaluronidase. In conclusion, the current data suggest that adenosine via adenosine A2(B)R and A2(A)R/A3R induces HAS1. In turn a HA-rich matrix is formed by HCASMC which likely supports the migratory HCASMC phenotype and traps monocytes/macrophages in the interstitial matrix.
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Affiliation(s)
- M Grandoch
- Institut für Pharmakologie u. Klinische Pharmakologie, Universitätsklinikum der Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany.
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30
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Zhang X, Szeto C, Gao E, Tang M, Jin J, Fu Q, Makarewich C, Ai X, Li Y, Tang A, Wang J, Gao H, Wang F, Ge XJ, Kunapuli SP, Zhou L, Zeng C, Xiang KY, Chen X. Cardiotoxic and cardioprotective features of chronic β-adrenergic signaling. Circ Res 2012; 112:498-509. [PMID: 23104882 DOI: 10.1161/circresaha.112.273896] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE In the failing heart, persistent β-adrenergic receptor activation is thought to induce myocyte death by protein kinase A (PKA)-dependent and PKA-independent activation of calcium/calmodulin-dependent kinase II. β-adrenergic signaling pathways also are capable of activating cardioprotective mechanisms. OBJECTIVE This study used a novel PKA inhibitor peptide to inhibit PKA activity to test the hypothesis that β-adrenergic receptor signaling causes cell death through PKA-dependent pathways and cardioprotection through PKA-independent pathways. METHODS AND RESULTS In PKA inhibitor peptide transgenic mice, chronic isoproterenol failed to induce cardiac hypertrophy, fibrosis, and myocyte apoptosis, and decreased cardiac function. In cultured adult feline ventricular myocytes, PKA inhibition protected myocytes from death induced by β1-adrenergic receptor agonists by preventing cytosolic and sarcoplasmic reticulum Ca(2+) overload and calcium/calmodulin-dependent kinase II activation. PKA inhibition revealed a cardioprotective role of β-adrenergic signaling via cAMP/exchange protein directly activated by cAMP/Rap1/Rac/extracellular signal-regulated kinase pathway. Selective PKA inhibition causes protection in the heart after myocardial infarction that was superior to β-blocker therapy. CONCLUSIONS These results suggest that selective block of PKA could be a novel heart failure therapy.
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Affiliation(s)
- Xiaoying Zhang
- Cardiovascular Research Center, Department of Physiology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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31
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Abstract
Chronic inflammatory diseases, such as atherosclerosis, are a major cause of death and disability in the developed world. In this respect, although cholesterol obviously plays a predominant role in atherosclerosis, targeting inflammation at lesion sites may be just as important. Indeed, elevated IL-6 (interleukin 6) levels are as strongly associated with coronary heart disease as increased cholesterol. We have been investigating novel cAMP-regulated pathways that combat the action of pro-inflammatory cytokines, such as IL-6 and leptin, in the VECs (vascular endothelial cells) of the circulatory system. In this respect, we have begun to unravel new molecular mechanisms by which the cAMP/Epac1 (exchange protein directly activated by cAMP 1)/Rap1 pathway can initiate a rigorous programme of protective anti-inflammatory responses in VECs. Central to this is the coupling of cAMP elevation to the mobilization of two C/EBP (CCAAT/enhancer-binding protein) family transcription factors, resulting in the induction of the SOCS3 (suppressor of cytokine signalling 3) gene, which attenuates pro-inflammatory cytokine signalling in VECs. These novel 'protective' mechanisms of cAMP action will inform the development of the next generation of pharmaceuticals specifically designed to combat endothelial inflammation associated with cardiovascular disease.
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Inhibitory effects of Rap1GAP overexpression on proliferation and migration of endothelial cells via ERK and Akt pathways. ACTA ACUST UNITED AC 2011; 31:721-727. [DOI: 10.1007/s11596-011-0667-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Indexed: 01/28/2023]
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Chen A, Dong L, Leffler NR, Asch AS, Witte ON, Yang LV. Activation of GPR4 by acidosis increases endothelial cell adhesion through the cAMP/Epac pathway. PLoS One 2011; 6:e27586. [PMID: 22110680 PMCID: PMC3217975 DOI: 10.1371/journal.pone.0027586] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 10/20/2011] [Indexed: 01/11/2023] Open
Abstract
Endothelium-leukocyte interaction is critical for inflammatory responses. Whereas the tissue microenvironments are often acidic at inflammatory sites, the mechanisms by which cells respond to acidosis are not well understood. Using molecular, cellular and biochemical approaches, we demonstrate that activation of GPR4, a proton-sensing G protein-coupled receptor, by isocapnic acidosis increases the adhesiveness of human umbilical vein endothelial cells (HUVECs) that express GPR4 endogenously. Acidosis in combination with GPR4 overexpression further augments HUVEC adhesion with U937 monocytes. In contrast, overexpression of a G protein signaling-defective DRY motif mutant (R115A) of GPR4 does not elicit any increase of HUVEC adhesion, indicating the requirement of G protein signaling. Downregulation of GPR4 expression by RNA interference reduces the acidosis-induced HUVEC adhesion. To delineate downstream pathways, we show that inhibition of adenylate cyclase by inhibitors, 2',5'-dideoxyadenosine (DDA) or SQ 22536, attenuates acidosis/GPR4-induced HUVEC adhesion. Consistently, treatment with a cAMP analog or a G(i) signaling inhibitor increases HUVEC adhesiveness, suggesting a role of the G(s)/cAMP signaling in this process. We further show that the cAMP downstream effector Epac is important for acidosis/GPR4-induced cell adhesion. Moreover, activation of GPR4 by acidosis increases the expression of vascular adhesion molecules E-selectin, VCAM-1 and ICAM-1, which are functionally involved in acidosis/GPR4-mediated HUVEC adhesion. Similarly, hypercapnic acidosis can also activate GPR4 to stimulate HUVEC adhesion molecule expression and adhesiveness. These results suggest that acidosis/GPR4 signaling regulates endothelial cell adhesion mainly through the G(s)/cAMP/Epac pathway and may play a role in the inflammatory response of vascular endothelial cells.
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Affiliation(s)
- Aishe Chen
- Department of Internal Medicine, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Lixue Dong
- Department of Internal Medicine, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Nancy R. Leffler
- Department of Internal Medicine, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Adam S. Asch
- Department of Internal Medicine, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
- UNC Lineberger Comprehensive Cancer Center, Chapel Hill, North Carolina, United States of America
| | - Owen N. Witte
- Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Li V. Yang
- Department of Internal Medicine, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
- Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
- UNC Lineberger Comprehensive Cancer Center, Chapel Hill, North Carolina, United States of America
- * E-mail:
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Zemskov E, Lucas R, Verin AD, Umapathy NS. P2Y receptors as regulators of lung endothelial barrier integrity. J Cardiovasc Dis Res 2011; 2:14-22. [PMID: 21716747 PMCID: PMC3120267 DOI: 10.4103/0975-3583.78582] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Endothelial cells (ECs), forming a semi-permeable barrier between the interior space of blood vessels and underlying tissues, control such diverse processes as vascular tone, homeostasis, adhesion of platelets, and leukocytes to the vascular wall and permeability of vascular wall for cells and fluids. Mechanisms which govern the highly clinically relevant process of increased EC permeability are under intense investigation. It is well known that loss of this barrier (permeability increase) results in tissue inflammation, the hall mark of inflammatory diseases such as acute lung injury and its severe form, acute respiratory distress syndrome. Little is known about processes which determine the endothelial barrier enhancement or protection against permeability increase. It is now well accepted that extracellular purines and pyrimidines are promising and physiologically relevant barrier-protective agents and their effects are mediated by interaction with cell surface P2Y receptors which belong to the superfamily of G-protein-coupled receptors. The therapeutic potential of P2Y receptors is rapidly expanding field in pharmacology and some selective agonists became recently available. Here, we present an overview of recently identified P2Y receptor agonists that enhance the pulmonary endothelial barrier and inhibit and/or reverse endothelial barrier disruption.
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Affiliation(s)
- Evgeny Zemskov
- Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA
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Verzijl D, IJzerman AP. Functional selectivity of adenosine receptor ligands. Purinergic Signal 2011; 7:171-92. [PMID: 21544511 PMCID: PMC3146648 DOI: 10.1007/s11302-011-9232-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 04/05/2011] [Indexed: 12/11/2022] Open
Abstract
Adenosine receptors are plasma membrane proteins that transduce an extracellular signal into the interior of the cell. Basically every mammalian cell expresses at least one of the four adenosine receptor subtypes. Recent insight in signal transduction cascades teaches us that the current classification of receptor ligands into agonists, antagonists, and inverse agonists relies very much on the experimental setup that was used. Upon activation of the receptors by the ubiquitous endogenous ligand adenosine they engage classical G protein-mediated pathways, resulting in production of second messengers and activation of kinases. Besides this well-described G protein-mediated signaling pathway, adenosine receptors activate scaffold proteins such as β-arrestins. Using innovative and sensitive experimental tools, it has been possible to detect ligands that preferentially stimulate the β-arrestin pathway over the G protein-mediated signal transduction route, or vice versa. This phenomenon is referred to as functional selectivity or biased signaling and implies that an antagonist for one pathway may be a full agonist for the other signaling route. Functional selectivity makes it necessary to redefine the functional properties of currently used adenosine receptor ligands and opens possibilities for new and more selective ligands. This review focuses on the current knowledge of functionally selective adenosine receptor ligands and on G protein-independent signaling of adenosine receptors through scaffold proteins.
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Affiliation(s)
- Dennis Verzijl
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Ad P. IJzerman
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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da Conceição AO, Rossi MH, de Oliveira FF, Takser L, Lafond J. Genipa americana (Rubiaceae) fruit extract affects mitogen-activated protein kinase cell pathways in human trophoblast-derived BeWo cells: implications for placental development. J Med Food 2011; 14:483-94. [PMID: 21480798 DOI: 10.1089/jmf.2009.0279] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Genipa americana L. (Rubiaceae) is a fruit tree and a traditional medicine used to treat anemia, icterus, asthma, and liver and spleen problems. The aim of the present study was to verify the effect of G. americana fruit ethanolic extract on the mechanism for proliferation and differentiation of trophoblast-like cells. Qualitative analysis of G. americana fruit extract was performed, and BeWo cells, a well-established placental choriocarcinoma cell line that can undergo differentiation, were used to analyze cell viability and proliferation. Methods consisted of cytotoxic and proliferation measurement, detection of release of human chorionic gonadotrophins, cell fusion observation, and evaluation of cell-signaling pathways (production of cyclic adenosine monophosphate and phosphorylation of mitogen-activated protein kinases [MAPKs]). A stock solution of the extract was diluted in Ham's F-12 medium with 10% fetal bovine serum at concentrations ranging from 50 to 1000 μg/mL. Cells treated with dimethylsulfoxide, forskoline, and MAPK inhibitors (PD98059 or SB203580) were used as a control. Forskoline was used to induce the differentiation state in BeWo cells. Phytoanalysis indicated the presence of steroids only. Results showed that the G. americana fruit extract did not cause any cytotoxicity or interference in cell differentiation. However, a significant antiproliferative state related to inhibition and reactivation of ERK1/2 and p38 MAPK in BeWo cells was seen. These results suggest that steroids from G. americana may affect placental cell regulation.
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Affiliation(s)
- Aline Oliveira da Conceição
- Laboratory of Maternal-Fetal Physiology, Department of Biological Sciences, University of Quebec at Montreal, Montreal, Quebec, Canada
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Mayer P, Hinze AV, Harst A, von Kügelgen I. A₂B receptors mediate the induction of early genes and inhibition of arterial smooth muscle cell proliferation via Epac. Cardiovasc Res 2010; 90:148-56. [PMID: 21109603 DOI: 10.1093/cvr/cvq371] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
AIMS Extracellular adenosine and adenine nucleotides play important roles in the regulation of the blood vessel tonus and platelet aggregation. Less is known about the effects of these extracellular signalling molecules on gene expression in vascular smooth muscle cells involved in long-term vascular effects. In the present study, we therefore searched for adenosine-induced changes in the expression of early genes in cultured human coronary artery smooth muscle cells (HCASMCs). METHODS AND RESULTS Whole-genome DNA array hybridization revealed that adenosine induced a set of early genes including the nuclear receptor subfamily 4, group A, member 1 (NR4A1/Nur77/TR3). The pattern of the effects of adenosine on gene expression resembles the change in expression induced by the direct activator of adenylate cyclase forskolin. Real-time reverse-transcriptase PCR confirmed that adenosine and its analogue N-ethyl-carboxamidoadenosine elicited a strong induction of NR4A1. These effects were markedly attenuated by A(2B) receptor antagonists including 8-[4-(4-benzylpiperazide-1-sulfonyl)phenyl]-1-propylxanthine (PSB-601) and were mimicked by a cyclic AMP (cAMP) analogue [8-(4-chlorophenylthio)-2'-O-methyl-cAMP, 8CPT] acting on the exchange protein activated by cAMP (Epac). Long-term experiments over 5 days showed that 2-chloroadenosine decreased cell proliferation in the presence of platelet-derived growth factor. This effect of 2-chloroadenosine was also attenuated by PSB-601 and mimicked by 8CPT. Treatment with small interfering RNA directed against NR4A1 attenuated the inhibitory effect of 8CPT on proliferation. CONCLUSIONS In summary, our results demonstrate the operation of adenosine A₂(B) receptors mediating an early induction of NR4A1 and a decrease in cell proliferation via the cAMP/Epac pathway in HCASMCs.
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Affiliation(s)
- Peter Mayer
- Federal Institute for Drugs and Medical Devices, Bonn, Germany.
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Ye Y, Perez-Polo JR, Birnbaum Y. Protecting against ischemia-reperfusion injury: antiplatelet drugs, statins, and their potential interactions. Ann N Y Acad Sci 2010; 1207:76-82. [PMID: 20955429 DOI: 10.1111/j.1749-6632.2010.05725.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Statins and antiplatelet agents are currently used as therapeutic agents for patients with acute myocardial infarction. Statins limit myocardial infarct size by activating phosphatidylinositol-3-kinase (PI3K), ecto-5'-nucleotidase, Akt/endothelial nitric oxide synthase (eNOS), and the downstream effectors inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Inhibition of PI3K, adenosine receptors, eNOS, iNOS, or COX-2 abrogates the protective effects of statins. At >5 mg/kg, aspirin attenuates the myocardial infarct-size-limiting effect of statins. In contrast, the combination of low-dose atoravastatin with either the phosphodiesterase-III inhibitor cilostazol or the adenosine reuptake inhibitor dipyridamole synergistically limits infarct size. Low-dose aspirin with dipyridamole started during ischemia augmented the infarct-size-limiting effects of simvastatin. In contrast, high-dose aspirin blocked the protective effect of simvastatin. The combination of dipyridamole with low-dose aspirin and simvastatin resulted in the smallest infarct size. According to the most current data available, we believe that antiplatelet regimens may require modification for patients who are receiving statins.
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Affiliation(s)
- Yumei Ye
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, USA
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Yoo AR, Koh SH, Cho GW, Kim SH. Inhibitory effects of cilostazol on proliferation of vascular smooth muscle cells (VSMCs) through suppression of the ERK1/2 pathway. J Atheroscler Thromb 2010; 17:1009-18. [PMID: 20720374 DOI: 10.5551/jat.4309] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
AIM The abnormal proliferation of vascular smooth muscle cells (VSMCs) in arterial walls is an important pathogenic factor of vascular disorders such as atherosclerosis and restenosis after angioplasty. During atherogenesis or in response to vessel injury, VSMC proliferation is induced by a number of peptide growth factors released from platelets and VSMCs. Cilostazol is a phosphodiesterase (PDE) 3 inhibitor that increases intracellular cAMP levels and decreases intracellular Ca(2+) levels, inhibiting platelet aggregation and inducing vasodilatation. Cilostazol is also known to have an inhibitory effect on the proliferation of VSMCs, but the anti-proliferative mechanism of cilostazol in VSMCs has not yet been established. In the present study, we investigated whether the anti-proliferative mechanism of cilostazol is associated with the suppression of extracellular signal-regulated kinases (ERK) and phosphatidylinositol 3 kinase (PI3K) signaling pathways. METHODS To confirm the anti-proliferative effects of cilostazol on VSMCs, VSMCs were induced to proliferate by serum-induced mitogenesis and then were treated with cilostazol for 24 h. And, to investigate whether the anti-proliferative mechanism of cilostazol in VSMCs involves the suppression of the ERK and PI3K pathways, expression of the phosphorylated forms of ERK1/2, Raf, Akt, and glycogen synthase kinase (GSK)-3 were evaluated by western blot. RESULTS Cilostazol inhibited VSMC proliferation in a dose-dependent manner. Phosphorylated ERK1/2 and Raf were significantly reduced in a dose-dependent manner, whereas phosphorylated Akt and GSK-3 were not changed. CONCLUSION These results suggest that suppression of the ERK pathway but not the PI3K pathway is an important mechanism in the anti-proliferative effect of cilostazol on VSMCs.
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Affiliation(s)
- A Rum Yoo
- Department of Neurology, Hanyang University College of Medicine, 17 Haengdang-dong-dong, Seoul, Korea
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Funaki C, Hodges RR, Dartt DA. Identification of the Raf-1 signaling pathway used by cAMP to inhibit p42/p44 MAPK in rat lacrimal gland acini: role in potentiation of protein secretion. Invest Ophthalmol Vis Sci 2010; 51:6321-8. [PMID: 20671279 DOI: 10.1167/iovs.10-5690] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
PURPOSE The lacrimal gland is primarily responsible for the aqueous portion of the tear film. Simultaneous addition of cholinergic agonists or growth factors with cAMP-dependent agonists potentiates secretion. Recent investigations revealed that cAMP decreases p44/p42 mitogen-activated protein kinase (MAPK) activity stimulated by cholinergic agonists and growth factors that could account for this potentiation. In this study the authors identify the signal transduction pathway used by cAMP to inhibit MAPK activity. METHODS Rat lacrimal gland acini were incubated with H89, an inhibitor of protein kinase A, before the addition of dibutyryl cAMP (dbcAMP, 10(-3) M) for 30 minutes. Basal MAPK and CREB activity and MAPK activity after stimulation with the cholinergic agonist carbachol (Cch) or epidermal growth factor (EGF) for 5 minutes was determined. The effect of dbcAMP on EGF receptor activity and basal and stimulated Ras, Raf-1, mitogen-activated protein kinase kinase (MEK), and MAPK activity was determined. The effect of a Rap-1 inhibitor, GGTI-298, on MAPK activity after the addition of dbcAMP was also determined. RESULTS H89 relieved the inhibition of cAMP on MAPK activity and inhibited CREB activity. Incubation with dbcAMP did not have any effect either on the EGF receptor or on Ras but significantly inhibited both basal and Raf-1 and MEK activity stimulated with Cch or EGF. GGTI-298 did not have any effect on cAMP-dependent decrease in MAPK activity. CONCLUSIONS The authors conclude that cAMP mediates the inhibition of MAPK by PKA in a Raf-1-dependent manner.
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Affiliation(s)
- Chika Funaki
- Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
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Misra UK, Pizzo SV. Epac1-induced cellular proliferation in prostate cancer cells is mediated by B-Raf/ERK and mTOR signaling cascades. J Cell Biochem 2010; 108:998-1011. [PMID: 19725049 DOI: 10.1002/jcb.22333] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
cAMP-dependent, PKA-independent effects on cell proliferation are mediated by cAMP binding to EPAC and activation of Rap signaling. In this report, we employed the analogue 8-CPT-2-O-Me-cAMP to study binding to EPAC and subsequent activation of B-Raf/ERK and mTOR signaling in human cancer cells. This compound significantly stimulated DNA synthesis, protein synthesis, and cellular proliferation of human 1-LN prostate cancer cells. By study of phosphorylation-dependent activation, we demonstrate that EPAC-mediated cellular effects require activation of the B-Raf/ERK and mTOR signaling cascades. RNAi directed against EPAC gene expression as well as inhibitors of ERK, PI 3-kinase, and mTOR were employed to further demonstrate the role of these pathways in regulating prostate cancer cell proliferation. These studies were then extended to several other human prostate cancer cell lines and melanoma cells with comparable results. We conclude that B-Raf/ERK and mTOR signaling play an essential role in cAMP-dependent, but PKA-independent, proliferation of cancer cells.
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Affiliation(s)
- Uma Kant Misra
- Department of Pathology, Duke University Medical Center, Durham, North Carolina 27710, USA
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Pettengill MA, Lam VW, Ojcius DM. The danger signal adenosine induces persistence of chlamydial infection through stimulation of A2b receptors. PLoS One 2009; 4:e8299. [PMID: 20011598 PMCID: PMC2788228 DOI: 10.1371/journal.pone.0008299] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 11/08/2009] [Indexed: 11/18/2022] Open
Abstract
Infections with intracellular bacteria such as chlamydiae affect the majority of the world population. Infected tissue inflammation and granuloma formation help contain the short-term expansion of the invading pathogen, leading also to local tissue damage and hypoxia. However, the effects of key aspects of damaged inflamed tissues and hypoxia on continued infection with intracellular bacteria remain unknown. We find that development of Chlamydia trachomatis is reversibly retarded by prolonged exposure of infected cells to extracellular adenosine, a hallmark of hypoxia and advanced inflammation. In epithelial cells, this effect was mediated by the A2b adenosine receptor, unique in the adenosine receptor family for having a hypoxia-inducible factor (HIF1-α) binding site at its promoter region, and was dependent on an increase in the intracellular cAMP levels, but was independent of cAMP-dependent protein kinase (PKA). Further study of adenosine receptor signaling during intracellular bacterial infection could lead to breakthroughs in our understanding of persistent infections with these ubiquitous pathogens.
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Affiliation(s)
- Matthew A Pettengill
- Health Sciences Research Institute and School of Natural Sciences, University of California Merced, Merced, California, United States of America
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Kanda N, Ishikawa T, Watanabe S. Prostaglandin D2 induces the production of human beta-defensin-3 in human keratinocytes. Biochem Pharmacol 2009; 79:982-9. [PMID: 19925780 DOI: 10.1016/j.bcp.2009.11.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 11/09/2009] [Accepted: 11/10/2009] [Indexed: 01/01/2023]
Abstract
The antimicrobial peptide human beta-defensin-3 (hBD-3) is produced by epidermal keratinocytes and protects the skin from infections. This peptide induces the release of a lipid mediator, prostaglandin D(2) from dermal mast cells. Prostaglandin D(2) binds to cell-surface G protein-coupled receptors, D prostanoid receptor, and chemoattractant receptor-homologous molecule expressed on T helper cell type 2 (CRTH2). Both receptors are detected on epidermal keratinocytes. It is reported that prostaglandin D(2) is involved in cutaneous allergy, however, its role in antimicrobial defense is unknown. We examined the in vitro effects of prostaglandin D(2) on hBD-3 production in normal human keratinocytes. Prostaglandin D(2) enhanced hBD-3 secretion and mRNA expression in human keratinocytes. Prostaglandin D(2)-induced hBD-3 production was suppressed by the CRTH2 antagonist ramatroban and by antisense oligonucleotides against c-Jun and c-Fos, components of a transcription factor, activator protein-1 (AP-1). Prostaglandin D(2) enhanced the transcriptional activity and DNA binding of AP-1, expression, phosphorylation, and DNA binding of c-Fos proteins in keratinocytes. Prostaglandin D(2)-induced hBD-3 production, AP-1 activity, and c-Fos expression and phosphorylation were suppressed by U0126, PP2, and pertussis toxin, which are inhibitors of mitogen-activated protein kinase kinase (MEK), src, and G(i) proteins, respectively. The phosphorylation of extracellular signal-regulated kinase (ERK), downstream kinase of MEK, was induced by prostaglandin D(2), and suppressed by ramatroban, pertussis toxin, PP2, and U0126. These results suggest that prostaglandin D(2) induces hBD-3 production in human keratinocytes by activating AP-1 through the expression and phosphorylation of c-Fos via the CRTH2/G(i)/src/MEK/ERK pathway. Prostaglandin D(2) may promote cutaneous antimicrobial activity via hBD-3.
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Affiliation(s)
- Naoko Kanda
- Department of Dermatology, Teikyo University School of Medicine, 11-1, Kaga-2, Itabashi-Ku, Tokyo 173-8605, Japan.
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Grandoch M, Rose A, ter Braak M, Jendrossek V, Rübben H, Fischer JW, Schmidt M, Weber AA. Epac inhibits migration and proliferation of human prostate carcinoma cells. Br J Cancer 2009; 101:2038-42. [PMID: 19920825 PMCID: PMC2795436 DOI: 10.1038/sj.bjc.6605439] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Background: It was recently found that cAMP mediates protein kinase A-independent effects through Epac proteins. The aim of this study was to investigate the role of Epac in migration and proliferation of prostate carcinoma cells. Methods: The effect of Epac activation was determined by [3H]thymidine incorporation and scratch assays in PC-3 and DU 145 cells. Furthermore, cytoskeletal integrity was analysed by phalloidin staining. The participation of intracellular Epac effectors such as mitogen-activated protein (MAP) kinases, Rap1- and Rho-GTPases was determined by immunoblotting and pull-down assay. Results: The specific Epac activator 8-pCPT-2′-O-Me-cAMP (8-pCPT) interfered with cytoskeletal integrity, reduced DNA synthesis, and migration. Although 8-pCPT activated Rap1, it inhibited MAP kinase signalling and RhoA activation. These findings were translated into functional effects such as inhibition of mitogenesis, cytoskeletal integrity, and migration. Conclusion: In human prostate carcinoma cells, Epac inhibits proliferative and migratory responses likely because of inhibition of MAP kinase and RhoA signalling pathways. Therefore, Epac might represent an attractive therapeutic target in the treatment of prostate cancer.
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Affiliation(s)
- M Grandoch
- Department of Pharmacology, University of Essen Medical School, Essen, Germany.
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Grandoch M, Roscioni SS, Schmidt M. The role of Epac proteins, novel cAMP mediators, in the regulation of immune, lung and neuronal function. Br J Pharmacol 2009; 159:265-84. [PMID: 19912228 DOI: 10.1111/j.1476-5381.2009.00458.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chronic degenerative inflammatory diseases, such as chronic obstructive pulmonary disease and Alzheimer's dementia, afflict millions of people around the world, causing death and debilitation. Despite the global impact of these diseases, there have been few innovative breakthroughs into their cause, treatment or cure. As with many debilitating disorders, chronic degenerative inflammatory diseases may be associated with defective or dysfunctional responses to second messengers, such as cyclic adenosinemonophosphate (cAMP). The identification of the cAMP-activated guanine nucleotide exchange factors for Ras-like GTPases, Epac1 (also known as cAMP-GEF-I) and Epac2 (also known as cAMP-GEF-II), profoundly altered the prevailing assumptions concerning cAMP signalling, which until then had been solely associated with protein kinase A (PKA). Studies of the molecular mechanisms of Epac-related signalling have demonstrated that these novel cAMP sensors regulate many physiological processes either alone and/or in concert with PKA. These include calcium handling, cardiac and smooth muscle contraction, learning and memory, cell proliferation and differentiation, apoptosis, and inflammation. The diverse signalling properties of cAMP might be explained by spatio-temporal compartmentalization, as well as A-kinase anchoring proteins, which seem to coordinate Epac signalling networks. Future research should focus on the Epac-regulated dynamics of cAMP, and, hopefully, the development of compounds that specifically interfere with the Epac signalling system in order to determine the precise significance of Epac proteins in chronic degenerative inflammatory disorders.
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Affiliation(s)
- Maria Grandoch
- Institut für Pharmakologie, Universitätsklinikum Essen, Essen, Germany
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Roscioni SS, Kistemaker LEM, Menzen MH, Elzinga CRS, Gosens R, Halayko AJ, Meurs H, Schmidt M. PKA and Epac cooperate to augment bradykinin-induced interleukin-8 release from human airway smooth muscle cells. Respir Res 2009; 10:88. [PMID: 19788733 PMCID: PMC2764632 DOI: 10.1186/1465-9921-10-88] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2009] [Accepted: 09/29/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Airway smooth muscle contributes to the pathogenesis of pulmonary diseases by secreting inflammatory mediators such as interleukin-8 (IL-8). IL-8 production is in part regulated via activation of Gq-and Gs-coupled receptors. Here we study the role of the cyclic AMP (cAMP) effectors protein kinase A (PKA) and exchange proteins directly activated by cAMP (Epac1 and Epac2) in the bradykinin-induced IL-8 release from a human airway smooth muscle cell line and the underlying molecular mechanisms of this response. METHODS IL-8 release was assessed via ELISA under basal condition and after stimulation with bradykinin alone or in combination with fenoterol, the Epac activators 8-pCPT-2'-O-Me-cAMP and Sp-8-pCPT-2'-O-Me-cAMPS, the PKA activator 6-Bnz-cAMP and the cGMP analog 8-pCPT-2'-O-Me-cGMP. Where indicated, cells were pre-incubated with the pharmacological inhibitors Clostridium difficile toxin B-1470 (GTPases), U0126 (extracellular signal-regulated kinases ERK1/2) and Rp-8-CPT-cAMPS (PKA). The specificity of the cyclic nucleotide analogs was confirmed by measuring phosphorylation of the PKA substrate vasodilator-stimulated phosphoprotein. GTP-loading of Rap1 and Rap2 was evaluated via pull-down technique. Expression of Rap1, Rap2, Epac1 and Epac2 was assessed via western blot. Downregulation of Epac protein expression was achieved by siRNA. Unpaired or paired two-tailed Student's t test was used. RESULTS The beta2-agonist fenoterol augmented release of IL-8 by bradykinin. The PKA activator 6-Bnz-cAMP and the Epac activator 8-pCPT-2'-O-Me-cAMP significantly increased bradykinin-induced IL-8 release. The hydrolysis-resistant Epac activator Sp-8-pCPT-2'-O-Me-cAMPS mimicked the effects of 8-pCPT-2'-O-Me-cAMP, whereas the negative control 8-pCPT-2'-O-Me-cGMP did not. Fenoterol, forskolin and 6-Bnz-cAMP induced VASP phosphorylation, which was diminished by the PKA inhibitor Rp-8-CPT-cAMPS. 6-Bnz-cAMP and 8-pCPT-2'-O-Me-cAMP induced GTP-loading of Rap1, but not of Rap2. Treatment of the cells with toxin B-1470 and U0126 significantly reduced bradykinin-induced IL-8 release alone or in combination with the activators of PKA and Epac. Interestingly, inhibition of PKA by Rp-8-CPT-cAMPS and silencing of Epac1 and Epac2 expression by specific siRNAs largely decreased activation of Rap1 and the augmentation of bradykinin-induced IL-8 release by both PKA and Epac. CONCLUSION Collectively, our data suggest that PKA, Epac1 and Epac2 act in concert to modulate inflammatory properties of airway smooth muscle via signaling to the Ras-like GTPase Rap1 and to ERK1/2.
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Affiliation(s)
- Sara S Roscioni
- Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands.
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Wang Y, Klein JD, Blount MA, Martin CF, Kent KJ, Pech V, Wall SM, Sands JM. Epac regulates UT-A1 to increase urea transport in inner medullary collecting ducts. J Am Soc Nephrol 2009; 20:2018-24. [PMID: 19661162 PMCID: PMC2736771 DOI: 10.1681/asn.2008121225] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Accepted: 06/20/2009] [Indexed: 11/03/2022] Open
Abstract
Urea plays a critical role in the concentration of urine, thereby regulating water balance. Vasopressin, acting through cAMP, stimulates urea transport across rat terminal inner medullary collecting ducts (IMCD) by increasing the phosphorylation and accumulation at the apical plasma membrane of UT-A1. In addition to acting through protein kinase A (PKA), cAMP also activates Epac (exchange protein activated by cAMP). In this study, we tested whether the regulation of urea transport and UT-A1 transporter activity involve Epac in rat IMCD. Functional analysis showed that an Epac activator significantly increased urea permeability in isolated, perfused rat terminal IMCD. Similarly, stimulating Epac by adding forskolin and an inhibitor of PKA significantly increased urea permeability. Incubation of rat IMCD suspensions with the Epac activator significantly increased UT-A1 phosphorylation and its accumulation in the plasma membrane. Furthermore, forskolin-stimulated cAMP significantly increased ERK 1/2 phosphorylation, which was not prevented by inhibiting PKA, indicating that Epac mediated this phosphorylation of ERK 1/2. Inhibition of MEK 1/2 phosphorylation decreased the forskolin-stimulated UT-A1 phosphorylation. Taken together, activation of Epac increases urea transport, accumulation of UT-A1 at the plasma membrane, and UT-A1 phosphorylation, the latter of which is mediated by the MEK-ERK pathway.
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Affiliation(s)
- Yanhua Wang
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Janet D. Klein
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Mitsi A. Blount
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Christopher F. Martin
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Kimilia J. Kent
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Vladimir Pech
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Susan M. Wall
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Jeff M. Sands
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
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A novel interplay between Epac/Rap1 and mitogen-activated protein kinase kinase 5/extracellular signal-regulated kinase 5 (MEK5/ERK5) regulates thrombospondin to control angiogenesis. Blood 2009; 114:4592-600. [PMID: 19710505 DOI: 10.1182/blood-2009-04-217042] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tumors depend upon angiogenesis for growth and metastasis. It is therefore critical to understand the inhibitory signaling mechanisms in endothelial cells that control angiogenesis. Epac is a cyclic adenosine 5'-monophosphate-activated guanine nucleotide exchange factor for Rap1. In this study, we show that activation of Epac or Rap1 leads to potent inhibition of angiogenesis in vivo. Epac/Rap1 activation down-regulates inhibitor of differentiation 1 (Id1), which negatively regulates thrombospondin-1 (TSP1), an inhibitor of angiogenesis. Consistent with this mechanism, activation of Epac/Rap 1 induces expression of TSP1; conversely, depletion of Epac reduces TSP1 levels in endothelial cells. Blockade of TSP1 binding to its receptor, CD36, rescues inhibition of chemotaxis or angiogenesis by activated Epac/Rap1. Mitogen-activated protein kinase kinase 5, a downstream mediator of vascular endothelial growth factor, antagonizes the effects of Epac/Rap1 by inducing Id1 and suppressing TSP1 expression. Finally, TSP1 is also secreted by fibroblasts in response to Epac/Rap1 activation. These results identify Epac and Rap1 as inhibitory regulators of the angiogenic process, implicate Id1 and TSP1 as downstream mediators of Epac/Rap1, and highlight a novel interplay between pro- and antiangiogenic signaling cascades involving multiple cell types within the angiogenic microenvironment.
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Selective inhibition of cytokine-activated extracellular signal-regulated kinase by cyclic AMP via Epac1-dependent induction of suppressor of cytokine signalling-3. Cell Signal 2009; 21:1706-15. [PMID: 19632320 DOI: 10.1016/j.cellsig.2009.07.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Revised: 07/10/2009] [Accepted: 07/16/2009] [Indexed: 11/21/2022]
Abstract
Here we demonstrate that elevation of cyclic AMP (cAMP) levels in human umbilical vein endothelial cells (HUVECs) specifically attenuates ERK1,2 activation in response to either leptin or a soluble interleukin IL-6 receptor-alpha/IL-6 (sIL-6R alpha/IL-6) trans-signalling complex but not protein kinase C activator phorbol 12-myristate 13-acetate. The inhibitory effects of cAMP on sIL-6R alpha/IL-6-stimulated phosphorylation of ERK1,2 and STAT3 were abolished by either short interfering (si) RNA-mediated knockdown or genetic ablation of suppressor of cytokine signalling-3 (SOCS-3). The inhibitory effect of cAMP could not be reversed by inhibition of cAMP-dependent protein kinase (PKA) but was blocked by depletion of the alternative intracellular cAMP sensor exchange protein activated by cAMP 1 (Epac1), which is also required to observe SOCS-3 accumulation in response to cAMP. Interestingly, the ability of cAMP elevation to inhibit IL-6 signalling was blocked by ERK inhibition. Consistent with this observation, cAMP elevation in HUVECs produced a transient yet robust activation of ERK, and subsequent phosphorylation of transcription factor C/EBP beta, both of which were resistant to PKA inhibition. However, siRNA depletion and immunoblotting experiments revealed that neither Epac1 nor Epac2 contributed to the PKA-independent activation of ERK1,2 observed following cAMP elevation. Together, these observations suggest that while SOCS-3 induction and subsequent inhibition of cytokine-mediated phosphorylation of ERK1,2 and STAT3 in response to cAMP require Epac1 and a transient PKA-independent activation of the ERK pathway, these two events are controlled by distinct mechanisms. In addition, it reveals a novel Epac-dependent mechanism by which cAMP can specifically inhibit ERK in response to cytokine receptor activation.
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Van Kolen K, Dautzenberg FM, Verstraeten K, Royaux I, De Hoogt R, Gutknecht E, Peeters PJ. Corticotropin releasing factor-induced ERK phosphorylation in AtT20 cells occurs via a cAMP-dependent mechanism requiring EPAC2. Neuropharmacology 2009; 58:135-44. [PMID: 19573542 DOI: 10.1016/j.neuropharm.2009.06.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 06/15/2009] [Accepted: 06/22/2009] [Indexed: 11/24/2022]
Abstract
CRF-induced ERK phosphorylation has been shown to be an important mechanism underlying expression of pro-opiomelanocortin, a key precursor molecule in the hypothalamic pituitary adrenal axis. In AtT20 cells, CRF signalling has been investigated but the mechanism behind CRF-induced ERK activity is not fully understood. This paper elucidates the signalling cascade involved in this phenomenon. Involvement of CRF(1) receptor on ERK phosphorylation was shown by using CRF and urocortin 1. The lack of inhibitory effect of pertussis toxin and BAPTA-AM excluded involvement of G(i)-coupling and calcium mobilization respectively. In contrast, the process is suggested to be driven by cAMP since treatment of AtT20 cells with forskolin triggered strong ERK phosphorylation. Treatment with PKA inhibitors had a minor effect on CRF-induced ERK signalling while phosphorylation of CREB was completely abolished. This ruled out involvement of PKA and suggested a role for exchange protein directly activated by cAMP (EPAC). Moreover, an activator of EPACs 8-(4-methoxyphenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate mimicked CRF-induced ERK phosphorylation. Gene expression analysis showed high levels of EPAC2 mRNA and protein but low levels of EPAC1. Knockdown of EPAC2 expression by the use of specific siRNAs abolished CRF- and forskolin-induced ERK phosphorylation. The current study demonstrates a clear cAMP-dependent but PKA-independent mechanism underlying CRF-induced ERK activity that proceeds via EPAC2 signalling. Further research will provide more insight in the role of EPAC2 in CRF signalling.
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Affiliation(s)
- Kristof Van Kolen
- CNS Discovery Research, Johnson & Johnson Pharmaceutical Research and Development, Division of Janssen Pharmaceutica N.V., Turnhoutseweg 30, B-2340 Beerse, Belgium.
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