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Yang W, Xia F, Mei F, Shi S, Robichaux WG, Lin W, Zhang W, Liu H, Cheng X. Upregulation of Epac1 Promotes Pericyte Loss by Inducing Mitochondrial Fission, Reactive Oxygen Species Production, and Apoptosis. Invest Ophthalmol Vis Sci 2023; 64:34. [PMID: 37651112 PMCID: PMC10476449 DOI: 10.1167/iovs.64.11.34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 08/09/2023] [Indexed: 09/01/2023] Open
Abstract
Purpose The pathogenic mechanisms behind the development of ischemic retinopathy are complex and poorly understood. This study investigates the involvement of exchange protein directly activated by cAMP (Epac)1 signaling in pericyte injury during ischemic retinopathy, including diabetic retinopathy, a disease that threatens vision. Methods Mouse models of retinal ischemia-reperfusion injury and type 1 diabetes induced by streptozotocin were used to investigate the pathogenesis of these diseases. The roles of Epac1 signaling in the pathogenesis of ischemic retinopathy were determined by an Epac1 knockout mouse model. The cellular and molecular mechanisms of Epac1-mediated pericyte dysfunction in response to high glucose were investigated by specific modulation of Epac1 activity in primary human retinal pericytes using Epac1-specific RNA interference and a pharmacological inhibitor. Results Ischemic injury or diabetes-induced retinal capillary degeneration were associated with an increased expression of Epac1 in the mouse retinal vasculature, including both endothelial cells and pericytes. Genetic deletion of Epac1 protected ischemic injury-induced pericyte loss and capillary degeneration in the mouse retina. Furthermore, high glucose-induced Epac1 expression in retinal pericytes was accompanied by increased Drp1 phosphorylation, mitochondrial fission, reactive oxygen species production, and caspase 3 activation. Inhibition of Epac1 via RNA interference or pharmacological approaches blocked high glucose-mediated mitochondrial dysfunction and caspase 3 activation. Conclusions Our study reveals an important role of Epac1 signaling in mitochondrial dynamics, reactive oxygen species production, and apoptosis in retinal pericytes and identifies Epac1 as a therapeutic target for treating ischemic retinopathy.
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Affiliation(s)
- Wenli Yang
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas, United States
- Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, United States
| | - Fan Xia
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
| | - Fang Mei
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas, United States
- Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, United States
| | - Shuizhen Shi
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
| | - William G. Robichaux
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas, United States
- Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, United States
| | - Wei Lin
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas, United States
- Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, United States
| | - Wenbo Zhang
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
- Department of Neurobiology, University of Texas Medical Branch, Galveston, Texas, United States
| | - Hua Liu
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas, United States
- Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, United States
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Walker LM, Haycocks JRJ, Van Kessel JC, Dalia TN, Dalia AB, Grainger DC. A simple mechanism for integration of quorum sensing and cAMP signalling in Vibrio cholerae. eLife 2023; 12:RP86699. [PMID: 37410076 DOI: 10.7554/elife.86699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023] Open
Abstract
Many bacteria use quorum sensing to control changes in lifestyle. The process is regulated by microbially derived 'autoinducer' signalling molecules, that accumulate in the local environment. Individual cells sense autoinducer abundance, to infer population density, and alter their behaviour accordingly. In Vibrio cholerae, quorum-sensing signals are transduced by phosphorelay to the transcription factor LuxO. Unphosphorylated LuxO permits expression of HapR, which alters global gene expression patterns. In this work, we have mapped the genome-wide distribution of LuxO and HapR in V. cholerae. Whilst LuxO has a small regulon, HapR targets 32 loci. Many HapR targets coincide with sites for the cAMP receptor protein (CRP) that regulates the transcriptional response to carbon starvation. This overlap, also evident in other Vibrio species, results from similarities in the DNA sequence bound by each factor. At shared sites, HapR and CRP simultaneously contact the double helix and binding is stabilised by direct interaction of the two factors. Importantly, this involves a CRP surface that usually contacts RNA polymerase to stimulate transcription. As a result, HapR can block transcription activation by CRP. Thus, by interacting at shared sites, HapR and CRP integrate information from quorum sensing and cAMP signalling to control gene expression. This likely allows V. cholerae to regulate subsets of genes during the transition between aquatic environments and the human host.
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Affiliation(s)
- Lucas M Walker
- School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - James R J Haycocks
- School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | | | - Triana N Dalia
- Department of Biology, Indiana University, Bloomington, United States
| | - Ankur B Dalia
- Department of Biology, Indiana University, Bloomington, United States
| | - David C Grainger
- School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
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3
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Targum SD, Schappi J, Koutsouris A, Bhaumik R, Rapaport MH, Rasgon N, Rasenick MM. A novel peripheral biomarker for depression and antidepressant response. Mol Psychiatry 2022; 27:1640-6. [PMID: 34969978 DOI: 10.1038/s41380-021-01399-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/13/2021] [Accepted: 11/23/2021] [Indexed: 12/20/2022]
Abstract
In contrast to healthy controls, the heterotrimeric G protein, Gsalpha (Gsα) is ensconced predominantly in lipid rafts in subjects with major depressive disorder (MDD) resulting in impaired stimulation of adenylyl cyclase. In this small proof-of-concept study, we examined the hypothesis that translocation of Gsα from lipid rafts toward a more facile activation of adenylyl cyclase is a biomarker for clinical response to antidepressants. There were 49 subjects with MDD (HamD17 score ≥15) and 59 healthy controls at the screen visit. The AlphaScreen (PerkinElmer) assay measured both basal activity and prostaglandin E1 (PGE1) stimulation of Gsα-adenylyl cyclase to assess the extent of coupling of Gsα with adenylyl cyclase. At screen, platelet samples obtained from MDD subjects revealed significantly lower PGE1 activation of adenylyl cyclase activity than controls (p = 0.02). Subsequently, 19 consenting MDD subjects completed a 6-week open label antidepressant treatment trial. The 11 antidepressant responders (HamD17 improvement ≥50% from screen) revealed significant increase in PGE1-stimulated adenylyl cyclase compared to non-responders (p = 0.05) with an effect size of 0.83 for the PGE1/Gsα lipid-raft biomarker. PGE1 stimulation increased by ≥30% from screen assessment in eight responders (72.7%) and two non-responders (25.0%) [Fisher exact = 0.07] with a positive predictive value for response of 80.0%. In this small, pilot study, increased PGE1 stimulated adenylyl cyclase was associated with antidepressant response in MDD subjects. These data suggest that a simple, high-throughput-capable assay for depression and antidepressant response can be developed. Future studies are needed to evaluate the utility of this biomarker for the treatment of MDD.
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Hansen JN, Kaiser F, Klausen C, Stüven B, Chong R, Bönigk W, Mick DU, Möglich A, Jurisch-Yaksi N, Schmidt FI, Wachten D. Nanobody-directed targeting of optogenetic tools to study signaling in the primary cilium. eLife 2020; 9:e57907. [PMID: 32579112 PMCID: PMC7338050 DOI: 10.7554/elife.57907] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 06/24/2020] [Indexed: 12/17/2022] Open
Abstract
Compartmentalization of cellular signaling forms the molecular basis of cellular behavior. The primary cilium constitutes a subcellular compartment that orchestrates signal transduction independent from the cell body. Ciliary dysfunction causes severe diseases, termed ciliopathies. Analyzing ciliary signaling has been challenging due to the lack of tools to investigate ciliary signaling. Here, we describe a nanobody-based targeting approach for optogenetic tools in mammalian cells and in vivo in zebrafish to specifically analyze ciliary signaling and function. Thereby, we overcome the loss of protein function observed after fusion to ciliary targeting sequences. We functionally localized modifiers of cAMP signaling, the photo-activated adenylyl cyclase bPAC and the light-activated phosphodiesterase LAPD, and the cAMP biosensor mlCNBD-FRET to the cilium. Using this approach, we studied the contribution of spatial cAMP signaling in controlling cilia length. Combining optogenetics with nanobody-based targeting will pave the way to the molecular understanding of ciliary function in health and disease.
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Affiliation(s)
- Jan N Hansen
- Institute of Innate Immunity, Biophysical Imaging, Medical Faculty, University of BonnBonnGermany
| | - Fabian Kaiser
- Institute of Innate Immunity, Biophysical Imaging, Medical Faculty, University of BonnBonnGermany
| | - Christina Klausen
- Institute of Innate Immunity, Biophysical Imaging, Medical Faculty, University of BonnBonnGermany
| | - Birthe Stüven
- Institute of Innate Immunity, Biophysical Imaging, Medical Faculty, University of BonnBonnGermany
| | - Raymond Chong
- Institute of Innate Immunity, Biophysical Imaging, Medical Faculty, University of BonnBonnGermany
| | - Wolfgang Bönigk
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar)BonnGermany
| | - David U Mick
- Center for Molecular Signaling (PZMS), Center of Human and Molecular Biology (ZHMB), Saarland University, School of MedicineHomburgGermany
| | - Andreas Möglich
- Lehrstuhl für Biochemie, Universität BayreuthBayreuthGermany
- Research Center for Bio-Macromolecules, Universität BayreuthBayreuthGermany
- Bayreuth Center for Biochemistry & Molecular Biology, Universität BayreuthBayreuthGermany
| | - Nathalie Jurisch-Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, The Faculty of Medicine, Norwegian University of Science and TechnologyTrondheimNorway
- Department of Neurology and Clinical Neurophysiology, St. Olavs University HospitalTrondheimNorway
| | - Florian I Schmidt
- Institute of Innate Immunity, Emmy Noether research group, Medical Faculty, University of BonnBonnGermany
- Core Facility Nanobodies, University of BonnBonnGermany
| | - Dagmar Wachten
- Institute of Innate Immunity, Biophysical Imaging, Medical Faculty, University of BonnBonnGermany
- Research Group Molecular Physiology, Center of Advanced European Studies and Research (caesar)BonnGermany
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Kamide T, Okumura S, Ghosh S, Shinoda Y, Mototani Y, Ohnuki Y, Jin H, Cai W, Suita K, Sato I, Umemura M, Fujita T, Yokoyama U, Sato M, Furutani K, Kitano H, Ishikawa Y. Oscillation of cAMP and Ca(2+) in cardiac myocytes: a systems biology approach. J Physiol Sci 2015; 65:195-200. [PMID: 25585963 PMCID: PMC10717207 DOI: 10.1007/s12576-014-0354-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 12/18/2014] [Indexed: 12/19/2022]
Abstract
Cyclic adenosine monophosphate (cAMP) and Ca(2+) levels may oscillate in harmony within excitable cells; a mathematical oscillation loop model, the Cooper model, of these oscillations was developed two decades ago. However, in that model all adenylyl cyclase (AC) isoforms were assumed to be inhibited by Ca(2+), and it is now known that the heart expresses multiple AC isoforms, among which the type 5/6 isoforms are Ca(2+)-inhibitable whereas the other five (AC2, 3, 4, 7, and 9) are not. We used a computational systems biology approach with CellDesigner simulation software to develop a comprehensive graphical map and oscillation loop model for cAMP and Ca(2+). This model indicated that Ca(2+)-mediated inhibition of AC is essential to create oscillations of Ca(2+) and cAMP, and the oscillations were not altered by incorporation of phosphodiesterase-mediated cAMP hydrolysis or PKA-mediated inhibition of AC into the model. More importantly, they were created but faded out immediately in the co-presence of Ca(2+)-noninhibitable AC isoforms. Because the subcellular locations of AC isoforms are different, spontaneous cAMP and Ca(2+) oscillations may occur within microdomains containing only Ca(2+)-inhibitable isoforms in cardiac myocytes, which might be necessary for fine tuning of excitation-contraction coupling.
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Affiliation(s)
- Takehisa Kamide
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Satoshi Okumura
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-2 Tsurumi, Tsurumi-ku, Yokohama, 230-8501 Japan
| | - Samik Ghosh
- The Systems Biology Institute, Minato, Tokyo, 108-0071 Japan
| | - Yoko Shinoda
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-2 Tsurumi, Tsurumi-ku, Yokohama, 230-8501 Japan
| | - Yasumasa Mototani
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-2 Tsurumi, Tsurumi-ku, Yokohama, 230-8501 Japan
| | - Yoshiki Ohnuki
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-2 Tsurumi, Tsurumi-ku, Yokohama, 230-8501 Japan
| | - Huiling Jin
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Wenqian Cai
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Kenji Suita
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Itaru Sato
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Masanari Umemura
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Takayuki Fujita
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Utako Yokoyama
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Motohiko Sato
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
- Department of Physiology, Aichi Medical University, Nagakute, Aichi 480-1195 Japan
| | - Kazuharu Furutani
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, 565-0871 Japan
- Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, 565-0871 Japan
| | - Hiroaki Kitano
- The Systems Biology Institute, Minato, Tokyo, 108-0071 Japan
- Okinawa Institute of Science and Technology Graduate School, Onna-Son, Okinawa, 904-0412 Japan
- Laboratory for Disease Systems Modeling, Riken Center for Integrative Medical Sciences, Yokohama, 230-0045 Japan
| | - Yoshihiro Ishikawa
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
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Pomianowska E, Sandnes D, Grzyb K, Schjølberg AR, Aasrum M, Tveteraas IH, Tjomsland V, Christoffersen T, Gladhaug IP. Inhibitory effects of prostaglandin E2 on collagen synthesis and cell proliferation in human stellate cells from pancreatic head adenocarcinoma. BMC Cancer 2014; 14:413. [PMID: 24912820 PMCID: PMC4084579 DOI: 10.1186/1471-2407-14-413] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 05/20/2014] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Several studies have described an increased cyclooxygenase-2 (COX-2) expression in pancreatic cancer, but the role of COX-2 in tumour development and progression is not clear. The aim of the present study was to examine expression of COX-2 in cancer cells and stromal cells in pancreatic cancer specimens, and to explore the role of PGE2 in pancreatic stellate cell proliferation and collagen synthesis. METHODS Immunohistochemistry and immunofluorescence was performed on slides from whole sections of tissue blocks using antibodies against COX-2 and α-smooth muscle actin (αSMA). Pancreatic stellate cells (PSC) were isolated from surgically resected tumour tissue by the outgrowth method. Cells were used between passages 4 and 8. Collagen synthesis was determined by [(3)H]-proline incorporation, or by enzyme immunoassay measurement of collagen C-peptide. DNA synthesis was measured by incorporation of [(3)H]-thymidine in DNA. Cyclic AMP (cAMP) was determined by radioimmunoassay. Collagen 1A1 mRNA was determined by RT-qPCR. RESULTS Immunohistochemistry staining showed COX-2 in pancreatic carcinoma cells, but not in stromal cells. All tumours showed positive staining for αSMA in the fibrotic stroma. Cultured PSC expressed COX-2, which could be further induced by interleukin-1β (IL-1β), epidermal growth factor (EGF), thrombin, and PGE2, but not by transforming growth factor-β1 (TGFβ). Indirect coculture with the adenocarcinoma cell line BxPC-3, but not HPAFII or Panc-1, induced COX-2 expression in PSC. Treatment of PSC with PGE2 strongly stimulated cAMP accumulation, mediated by EP2 receptors, and also stimulated phosphorylation of extracellular signal-regulated kinase (ERK). Treatment of PSC with PGE2 or forskolin suppressed both TGFβ-stimulated collagen synthesis and PDGF-stimulated DNA synthesis. CONCLUSIONS The present results show that COX-2 is mainly produced in carcinoma cells and suggest that the cancer cells are the main source of PGE2 in pancreatic tumours. PGE2 exerts a suppressive effect on proliferation and fibrogenesis in pancreatic stellate cells. These effects of PGE2 are mediated by the cAMP pathway and suggest a role of EP2 receptors.
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Affiliation(s)
- Ewa Pomianowska
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Hepato-pancreato-biliary Surgery, Oslo University Hospital, Rikshospitalet, PO Box 4956, Nydalen 0424 Oslo, Norway
| | - Dagny Sandnes
- Department of Pharmacology, Faculty of Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Krzysztof Grzyb
- Department of Pathology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Aasa R Schjølberg
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Monica Aasrum
- Department of Pharmacology, Faculty of Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Ingun H Tveteraas
- Department of Pharmacology, Faculty of Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Vegard Tjomsland
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Hepato-pancreato-biliary Surgery, Oslo University Hospital, Rikshospitalet, PO Box 4956, Nydalen 0424 Oslo, Norway
| | - Thoralf Christoffersen
- Department of Pharmacology, Faculty of Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Ivar P Gladhaug
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Hepato-pancreato-biliary Surgery, Oslo University Hospital, Rikshospitalet, PO Box 4956, Nydalen 0424 Oslo, Norway
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Gomez RA, Belyea B, Medrano S, Pentz ES, Sequeira-Lopez MLS. Fate and plasticity of renin precursors in development and disease. Pediatr Nephrol 2014; 29:721-6. [PMID: 24337407 PMCID: PMC3999616 DOI: 10.1007/s00467-013-2688-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 10/04/2013] [Accepted: 10/28/2013] [Indexed: 01/04/2023]
Abstract
Renin-expressing cells appear early in the embryo and are distributed broadly throughout the body as organogenesis ensues. Their appearance in the metanephric kidney is a relatively late event in comparison with other organs such as the fetal adrenal gland. The functions of renin cells in extra renal tissues remain to be investigated. In the kidney, they participate locally in the assembly and branching of the renal arterial tree and later in the endocrine control of blood pressure and fluid-electrolyte homeostasis. Interestingly, this endocrine function is accomplished by the remarkable plasticity of renin cell descendants along the kidney arterioles and glomeruli which are capable of reacquiring the renin phenotype in response to physiological demands, increasing circulating renin and maintaining homeostasis. Given that renin cells are sensors of the status of the extracellular fluid and perfusion pressure, several signaling mechanisms (β-adrenergic receptors, Notch pathway, gap junctions and the renal baroreceptor) must be coordinated to ensure the maintenance of renin phenotype--and ultimately the availability of renin--during basal conditions and in response to homeostatic threats. Notably, key transcriptional (Creb/CBP/p300, RBP-J) and posttranscriptional (miR-330, miR125b-5p) effectors of those signaling pathways are prominent in the regulation of renin cell identity. The next challenge, it seems, would be to understand how those factors coordinate their efforts to control the endocrine and contractile phenotypes of the myoepithelioid granulated renin-expressing cell.
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Affiliation(s)
- R Ariel Gomez
- Department of Pediatrics, University of Virginia School of Medicine, 409 Lane Road, Room 2001, Charlottesville, VA, 22908, USA,
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Murata S, Maruyama T, Nowatari T, Takahashi K, Ohkohchi N. Signal transduction of platelet-induced liver regeneration and decrease of liver fibrosis. Int J Mol Sci 2014; 15:5412-25. [PMID: 24686514 PMCID: PMC4013572 DOI: 10.3390/ijms15045412] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 03/16/2014] [Accepted: 03/20/2014] [Indexed: 12/16/2022] Open
Abstract
Platelets contain three types of granules: alpha granules, dense granules, and lysosomal granules. Each granule contains various growth factors, cytokines, and other physiological substances. Platelets trigger many kinds of biological responses, such as hemostasis, wound healing, and tissue regeneration. This review presents experimental evidence of platelets in accelerating liver regeneration and improving liver fibrosis. The regenerative effect of liver by platelets consists of three mechanisms; i.e., the direct effect on hepatocytes, the cooperative effect with liver sinusoidal endothelial cells, and the collaborative effect with Kupffer cells. Many signal transduction pathways are involved in hepatocyte proliferation. One is activation of Akt and extracellular signal-regulated kinase (ERK)1/2, which are derived from direct stimulation from growth factors in platelets. The other is signal transducer and activator of transcription-3 (STAT3) activation by interleukin (IL)-6 derived from liver sinusoidal endothelial cells and Kupffer cells, which are stimulated by contact with platelets during liver regeneration. Platelets also improve liver fibrosis in rodent models by inactivating hepatic stellate cells to decrease collagen production. The level of intracellular cyclic adenosine monophosphate (cyclic AMP) is increased by adenosine through its receptors on hepatic stellate cells, resulting in inactivation of these cells. Adenosine is produced by the degradation of adenine nucleotides such as adenosine diphosphate (ADP) and adenosine tri-phosphate (ATP), which are stored in abundance within the dense granules of platelets.
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Affiliation(s)
- Soichiro Murata
- Department of Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
| | - Takehito Maruyama
- Department of Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
| | - Takeshi Nowatari
- Department of Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
| | - Kazuhiro Takahashi
- Department of Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
| | - Nobuhiro Ohkohchi
- Department of Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
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Cope JL, Regev L, Chen Y, Korosi A, Rice CJ, Ji S, Rogge GA, Wood MA, Baram TZ. Differential contribution of CBP:CREB binding to corticotropin-releasing hormone expression in the infant and adult hypothalamus. Stress 2014; 17:39-50. [PMID: 23768074 PMCID: PMC3869921 DOI: 10.3109/10253890.2013.806907] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Corticotropin-releasing hormone (CRH) contributes crucially to the regulation of central and peripheral responses to stress. Because of the importance of a finely tuned stress system, CRH expression is tightly regulated in an organ- and brain region-specific manner. Thus, in the hypothalamus, CRH is constitutively expressed and this expression is further enhanced by stress; however, the underlying regulatory mechanisms are not fully understood. The regulatory region of the crh gene contains several elements, including the cyclic-AMP response element (CRE), and the role of the CRE interaction with the cyclic-AMP response element binding protein (CREB) in CRH expression has been a focus of intensive research. Notably, whereas thousands of genes contain a CRE, the functional regulation of gene expression by the CRE:CREB system is limited to ∼100 genes, and likely requires additional proteins. Here, we investigated the role of a member of the CREB complex, CREB binding protein (CBP), in basal and stress-induced CRH expression during development and in the adult. Using mice with a deficient CREB-binding site on CBP, we found that CBP:CREB interaction is necessary for normal basal CRH expression at the mRNA and protein level in the nine-day-old mouse, prior to onset of functional regulation of hypothalamic CRH expression by glucocorticoids. This interaction, which functions directly on crh or indirectly via regulation of other genes, was no longer required for maintenance of basal CRH expression levels in the adult. However, CBP:CREB binding contributed to stress-induced CRH expression in the adult, enabling rapid CRH synthesis in hypothalamus. CBP:CREB binding deficiency did not disrupt basal corticosterone plasma levels or acute stress-evoked corticosterone release. Because dysregulation of CRH expression occurs in stress-related disorders including depression, a full understanding of the complex regulation of this gene is important in both health and disease.
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Affiliation(s)
- Jessica L. Cope
- Department of Anatomy and Neurobiology, University of California-Irvine, Irvine, CA 92697, USA
| | - Limor Regev
- Department of Anatomy and Neurobiology, University of California-Irvine, Irvine, CA 92697, USA
| | - Yuncai Chen
- Department of Pediatrics, University of California-Irvine, Irvine, CA 92697, USA
| | - Aniko Korosi
- Department of Anatomy and Neurobiology, University of California-Irvine, Irvine, CA 92697, USA
| | - Courtney J. Rice
- Department of Anatomy and Neurobiology, University of California-Irvine, Irvine, CA 92697, USA
| | - Sung Ji
- Department of Anatomy and Neurobiology, University of California-Irvine, Irvine, CA 92697, USA
| | - George A. Rogge
- Department of Neurobiology and Behavior, University of California-Irvine, Irvine, CA 92697, USA
| | - Marcelo A. Wood
- Department of Neurobiology and Behavior, University of California-Irvine, Irvine, CA 92697, USA
| | - Tallie Z. Baram
- Department of Anatomy and Neurobiology, University of California-Irvine, Irvine, CA 92697, USA
- Department of Pediatrics, University of California-Irvine, Irvine, CA 92697, USA
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10
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Wheeler JI, Freihat L, Irving HR. A cyclic nucleotide sensitive promoter reporter system suitable for bacteria and plant cells. BMC Biotechnol 2013; 13:97. [PMID: 24206622 PMCID: PMC3829209 DOI: 10.1186/1472-6750-13-97] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 10/30/2013] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Cyclic AMP (cAMP) and cyclic GMP (cGMP) have roles in relaying external signals and modifying gene expression within cells in all phyla. Currently there are no reporter systems suitable for bacteria and plant cells that measure alterations in downstream gene expression following changes in intracellular levels of cyclic nucleotides. As the plant protein OLIGOPEPTIDE TRANSPORTER X (OPTX) is upregulated by cGMP, we fused the OPTX promoter to a luciferase reporter gene (OPTX:LUC) to develop a plant cell reporter of cGMP-induced gene expression. We prepared a second construct augmented with three mammalian cGMP response elements (OPTXcGMPRE:LUC) and a third construct containing five gibberellic acid response elements (OPTXGARE:LUC). All three constructs were tested in bacteria and isolated plant protoplasts. RESULTS Membrane permeable cGMP enhanced luciferase activity of OPTX:LUC and OPTXGARE:LUC in protoplasts. Treatment with the plant hormone gibberellic acid which acts via cGMP also generated downstream luciferase activity. However, membrane permeable cAMP induced similar responses to cGMP in protoplasts. Significantly increased luciferase activity occurred in bacteria transformed with either OPTXcGMPRE:LUC or OPTXGARE:LUC in response to membrane permeable cAMP and cGMP. Bacteria co-transformed with OPTXcGMPRE:LUC or OPTXGARE:LUC and the soluble cytoplasmic domain of phytosulfokine receptor1 (PSKR1; a novel guanylate cyclase) had enhanced luciferase activity following induction of PSKR1 expression. CONCLUSIONS We have developed promoter reporter systems based on the plant OPTX promoter that can be employed in bacteria and isolated plant cells. We have shown that it can be used in bacteria to screen recombinant proteins for guanylate cyclase activity as increases in intracellular cGMP levels result in altered gene transcription and luciferase activity.
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Affiliation(s)
- Janet I Wheeler
- Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Lubna Freihat
- Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Helen R Irving
- Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 381 Royal Parade, Parkville, VIC 3052, Australia
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11
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Kao RS, Abbott MJ, Louie A, O’Carroll D, Lu W, Nissenson R. Constitutive protein kinase A activity in osteocytes and late osteoblasts produces an anabolic effect on bone. Bone 2013; 55:277-87. [PMID: 23583750 PMCID: PMC3690773 DOI: 10.1016/j.bone.2013.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 03/30/2013] [Accepted: 04/02/2013] [Indexed: 11/19/2022]
Abstract
Osteocytes have been implicated in the control of bone formation. However, the signal transduction pathways that regulate the biological function of osteocytes are poorly defined. Limited evidence suggests an important role for the Gs/cAMP pathway in osteocyte function. In the present study, we explored the hypothesis that cAMP-dependent kinase A (PKA) activation in osteocytes plays a key role in controlling skeletal homeostasis. To test this hypothesis, we mated mice harboring a Cre-conditional, mutated PKA catalytic subunit allele that encodes a constitutively active form of PKA (CαR) with mice expressing Cre under the control of the osteocyte-specific promoter, DMP1. This allowed us to direct the expression of CαR to osteocytes in double transgenic progeny. Examination of Cre expression indicated that CαR was also expressed in late osteoblasts. Cortical and trabecular bone parameters from 12-week old mice were determined by μCT. Expression of CαR in osteocytes and late osteoblasts altered the shape of cortical bone proximal to the tibia-fibular junction (TFJ) and produced a significant increase in its size. In trabecular bone of the distal femur, fractional bone volume, trabecular number, and trabecular thickness were increased. These increases were partially the results of increased bone formation rates (BFRs) on the endosteal surface of the cortical bone proximal to the TFJ as well as increased BFR on the trabecular bone surface of the distal femur. Mice expressing CαR displayed a marked increase in the expression of osteoblast markers such as osterix, runx2, collagen 1α1, and alkaline phosphatase (ALP). Interestingly, expression of osteocyte marker gene, DMP1, was significantly up-regulated but the osteocyte number per bone area was not altered. Expression of SOST, a presumed target for PKA signaling in osteocytes, was significantly down-regulated in females. Importantly, no changes in bone resorption were detected. In summary, constitutive PKA signaling in osteocytes and late osteoblasts led to a small expansion of the size of the cortical bone proximal to the TFJ and an increase in trabecular bone in female mice. This was associated with down-regulation of SOST and up-regulation of several osteoblast marker genes. Activation of the PKA pathway in osteocytes and late osteoblasts is sufficient for the initiation of an anabolic skeletal response.
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Affiliation(s)
| | | | | | | | | | - Robert Nissenson
- Corresponding author at: University of California San Francisco, San Francisco, CA, USA. Fax: 415-750-6929.
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12
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Samal B, Ait-Ali D, Bunn S, Mustafa T, Eiden LE. Discrete signal transduction pathway utilization by a neuropeptide (PACAP) and a cytokine (TNF-alpha) first messenger in chromaffin cells, inferred from coupled transcriptome-promoter analysis of regulated gene cohorts. Peptides 2013; 45:48-60. [PMID: 23608709 PMCID: PMC3807697 DOI: 10.1016/j.peptides.2013.03.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Revised: 03/14/2013] [Accepted: 03/14/2013] [Indexed: 12/22/2022]
Abstract
Cultured bovine adrenal chromaffin cells (BCCs) are employed to study first messenger-specific signaling by cytokines and neurotransmitters occurring in the adrenal medulla following immune-related stress responses. Here, we show that the cytokine TNF-alpha, and the neuropeptide transmitter PACAP, acting through the TNFR2 and PAC1 receptors, activate distinct signaling pathways, with correspondingly distinct transcriptomic signatures in chromaffin cells. We have carried out a comprehensive integrated transcriptome analysis of TNF-alpha and PACAP gene regulation in BCCs using two microarray platforms to maximize transcript identification. Microarray data were validated using qRT-PCR. More than 90% of the transcripts up-regulated either by TNF-alpha or PACAP were specific to a single first messenger. The final list of transcripts induced by each first messenger was subjected to multiple algorithms to identify promoter/enhancer response elements for trans-acting factors whose activation could account for gene expression by either TNF-alpha or PACAP. Distinct groups of transcription factors potentially controlling the expression of TNF-alpha or PACAP-responsive genes were found: most of the genes up-regulated by TNF-alpha contained transcription factor binding sites for members of the Rel transcription factor family, suggesting TNF-alpha-TNFR2 signaling occurs mainly through the NF-KB signaling pathway. Surprisingly, EGR1 was predicted to be the primary transcription factor controlling PACAP-modulated genes, suggesting PACAP signaling to the nucleus occurs predominantly through ERK, rather than CREB activation. Comparison of TNFR2-dependent versus TNFR1-dependent gene induction, and EGR1-mediated transcriptional activation, may provide a pharmacological avenue to the unique pathways activated by the first messengers TNF-alpha and PACAP in neuronal and endocrine cells.
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MESH Headings
- Adrenal Glands/cytology
- Adrenal Glands/drug effects
- Adrenal Glands/immunology
- Animals
- Cattle
- Chromaffin Cells/cytology
- Chromaffin Cells/drug effects
- Chromaffin Cells/immunology
- Enhancer Elements, Genetic/drug effects
- Extracellular Signal-Regulated MAP Kinases/genetics
- Extracellular Signal-Regulated MAP Kinases/immunology
- Gene Expression Profiling
- Gene Expression Regulation
- NF-kappa B/genetics
- NF-kappa B/immunology
- Pituitary Adenylate Cyclase-Activating Polypeptide/pharmacology
- Primary Cell Culture
- Promoter Regions, Genetic/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/immunology
- Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I/genetics
- Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I/immunology
- Receptors, Tumor Necrosis Factor, Type II/genetics
- Receptors, Tumor Necrosis Factor, Type II/immunology
- Signal Transduction
- Stress, Physiological
- Transcriptome/drug effects
- Transcriptome/immunology
- Tumor Necrosis Factor-alpha/pharmacology
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Affiliation(s)
- Babru Samal
- Section on Molecular Neuroscience, Laboratory of Cellular and
Molecular Regulation, National Institute of Mental Health, Bethesda, MD 20892,
USA
| | - Djida Ait-Ali
- Section on Molecular Neuroscience, Laboratory of Cellular and
Molecular Regulation, National Institute of Mental Health, Bethesda, MD 20892,
USA
| | - Stephen Bunn
- Centre for Neuroendocrinology, Department of Anatomy, School of
Medical Sciences, University of Otego, PO Box 913, Dunedin, New Zealand
| | - Tomris Mustafa
- Section on Molecular Neuroscience, Laboratory of Cellular and
Molecular Regulation, National Institute of Mental Health, Bethesda, MD 20892,
USA
| | - Lee E. Eiden
- Section on Molecular Neuroscience, Laboratory of Cellular and
Molecular Regulation, National Institute of Mental Health, Bethesda, MD 20892,
USA
- Corresponding author at: Section on Molecular
Neuroscience, Building 49, Room 5A-38,9000 Rockville Pike, Bethesda, MD 20892,
USA. Tel.: +1 301 496 4110; fax: +1 301 402 1748
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13
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Shin SH, Lee YM. Glyceollins, a novel class of soybean phytoalexins, inhibit SCF-induced melanogenesis through attenuation of SCF/c-kit downstream signaling pathways. Exp Mol Med 2013; 45:e17. [PMID: 23559126 PMCID: PMC3641398 DOI: 10.1038/emm.2013.20] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 12/11/2012] [Accepted: 12/26/2012] [Indexed: 12/17/2022] Open
Abstract
The anti-melanogenesis effect of glyceollins was examined by melanin synthesis, tyrosinase activity assay in zebrafish embryos and in B16F10 melanoma cells. When developing zebrafish embryos were treated with glyceollins, pigmentation of the embryos, melanin synthesis and tyrosinase activity were all decreased compared with control zebrafish embryos. In situ expression of a pigment cell-specific gene, Sox10, was dramatically decreased by glyceollin treatment in the neural tubes of the trunk region of the embryos. Stem cell factor (SCF)/c-kit signaling pathways as well as expression of microphthalmia-associated transcription factor (MITF) were determined by western blot analysis. Glyceollins inhibited melanin synthesis, as well as the expression and activity of tyrosinase induced by SCF, in a dose-dependent manner in B16F10 melanoma cells. Pretreatment of B16F10 cells with glyceollins dose-dependently inhibited SCF-induced c-kit and Akt phosphorylation. Glyceollins significantly impaired the expression and activity of MITF. An additional inhibitory function of glyceollins was to effectively downregulate intracellular cyclic AMP levels stimulated by SCF in B16F10 cells. Glyceollins have a depigmentation/whitening activity in vitro and in vivo, and that this effect may be due to the inhibition of SCF-induced c-kit and tyrosinase activity through the blockade of downstream signaling pathway.
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Affiliation(s)
- Sun-Hye Shin
- School of Life Sciences and Biotechnology, College of Natural Sciences, Daegu, Republic of Korea
| | - You-Mie Lee
- School of Life Sciences and Biotechnology, College of Natural Sciences, Daegu, Republic of Korea
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Kyungpook National University, Daegu, Republic of Korea
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14
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Kim HE, Ishihara A, Lee SG. The effects of Caffeoylserotonin on inhibition of melanogenesis through the downregulation of MITF via the reduction of intracellular cAMP and acceleration of ERK activation in B16 murine melanoma cells. BMB Rep 2012; 45:724-9. [PMID: 23261059 PMCID: PMC4133815 DOI: 10.5483/bmbrep.2012.45.12.039] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 04/25/2012] [Accepted: 05/23/2012] [Indexed: 11/20/2022] Open
Abstract
In this study, we evaluated the anti-melanogenesis effects of Caffeoylserotonin (CaS) in B16 melanoma cells. Treatment with CaS reduced the melanin content and tyrosinase (TYR) activity in B16 melanoma cells in a dose-dependent manner. CaS inhibited the expression of melanogenesis-related proteins, including microphthalmia- associated transcription factor (MITF), TYR, and tyrosinase-related protein-1 (TRP-1), but not TRP-2. α-MSH is known to interact with melanocortin 1 receptor (MC1R) thus activating adenylyl cyclase and increasing intracellular cyclic AMP (cAMP) levels. Furthermore, cAMP activates extracellular signal-regulated kinase 2 (ERK2) via phosphorylation, which phosphorylates MITF, thereby targeting the transcription factor to proteasomes for degradation. The CaS reduced intracellular cAMP levels to unstimulated levels and activated ERK phosphorylation within 30 min. The ERK inhibitor PD98059 abrogated the suppressive effect of CaS on α-MSH-induced melanogenesis. Based on this study, the inhibitory effects of CaS on melanogenesis are derived from the downregulation of MITF signaling via the inhibition of intracellular cAMP levels, as well as acceleration of ERK activation.
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Affiliation(s)
- Hye-Eun Kim
- Department of Biotechnology, Bioenergy Research Center, Chonnam National University, Gwangju 500-757, Korea
| | - Atsushi Ishihara
- Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan
| | - Seong-Gene Lee
- Department of Biotechnology, Bioenergy Research Center, Chonnam National University, Gwangju 500-757, Korea
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15
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Borthakur A, Priyamvada S, Kumar A, Natarajan AA, Gill RK, Alrefai WA, Dudeja PK. A novel nutrient sensing mechanism underlies substrate-induced regulation of monocarboxylate transporter-1. Am J Physiol Gastrointest Liver Physiol 2012; 303:G1126-33. [PMID: 22982338 PMCID: PMC3517653 DOI: 10.1152/ajpgi.00308.2012] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Monocarboxylate transporter isoform-1 (MCT1) plays an important role in the absorption of short-chain fatty acids (SCFAs) in the colon. Butyrate, a major SCFA, serves as the primary energy source for the colonic mucosa, maintains epithelial integrity, and ameliorates intestinal inflammation. Previous studies have shown substrate (butyrate)-induced upregulation of MCT1 expression and function via transcriptional mechanisms. The present studies provide evidence that short-term MCT1 regulation by substrates could be mediated via a novel nutrient sensing mechanism. Short-term regulation of MCT1 by butyrate was examined in vitro in human intestinal C2BBe1 and rat intestinal IEC-6 cells and ex vivo in rat intestinal mucosa. Effects of pectin feeding on MCT1, in vivo, were determined in rat model. Butyrate treatment (30-120 min) of C2BBe1 cells increased MCT1 function {p-(chloromercuri) benzene sulfonate (PCMBS)-sensitive [(14)C]butyrate uptake} in a pertussis toxin-sensitive manner. The effects were associated with decreased intracellular cAMP levels, increased V(max) of butyrate uptake, and GPR109A-dependent increase in apical membrane MCT1 level. Nicotinic acid, an agonist for the SCFA receptor GPR109A, also increased MCT1 function and decreased intracellular cAMP. Pectin feeding increased apical membrane MCT1 levels and nicotinate-induced transepithelial butyrate flux in rat colon. Our data provide strong evidence for substrate-induced enhancement of MCT1 surface expression and function via a novel nutrient sensing mechanism involving GPR109A as a SCFA sensor.
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Affiliation(s)
- Alip Borthakur
- Section of Digestive Diseases & Nutrition, Dept. of Medicine, Univ. of Illinois at Chicago, Chicago, IL 60612, USA.
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16
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Cukkemane A, Nand D, Gradmann S, Weingarth M, Kaupp UB, Baldus M. Solid-state NMR [13C,15N] resonance assignments of the nucleotide-binding domain of a bacterial cyclic nucleotide-gated channel. Biomol NMR Assign 2012; 6:225-9. [PMID: 22302441 PMCID: PMC3438399 DOI: 10.1007/s12104-012-9363-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 01/17/2012] [Indexed: 05/21/2023]
Abstract
Channels regulated by cyclic nucleotides are key signalling proteins in several biological pathways. The regulatory aspect is conferred by a C-terminal cyclic nucleotide-binding domain (CNBD). We report resonance assignments of the CNBD of a bacterial mlCNG channel obtained using 2D and 3D solid-state NMR under Magic-angle Spinning conditions. A secondary chemical shift analysis of the 141 residue protein suggests a three-dimensional fold seen in earlier X-ray and solution-state NMR work and points to spectroscopic polymorphism for a selected set of resonances.
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Affiliation(s)
- Abhishek Cukkemane
- Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Deepak Nand
- Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Sabine Gradmann
- Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Markus Weingarth
- Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - U. Benjamin Kaupp
- Center of Advanced European Studies and Research (Caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Marc Baldus
- Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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17
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Abstract
Among organ systems, skeletal muscle is perhaps the most structurally specialized. The remarkable subcellular architecture of this tissue allows it to empower movement with instructions from motor neurons. Despite this high degree of specialization, skeletal muscle also has intrinsic signaling mechanisms that allow adaptation to long-term changes in demand and regeneration after acute damage. The second messenger adenosine 3',5'-monophosphate (cAMP) not only elicits acute changes within myofibers during exercise but also contributes to myofiber size and metabolic phenotype in the long term. Strikingly, sustained activation of cAMP signaling leads to pronounced hypertrophic responses in skeletal myofibers through largely elusive molecular mechanisms. These pathways can promote hypertrophy and combat atrophy in animal models of disorders including muscular dystrophy, age-related atrophy, denervation injury, disuse atrophy, cancer cachexia, and sepsis. cAMP also participates in muscle development and regeneration mediated by muscle precursor cells; thus, downstream signaling pathways may potentially be harnessed to promote muscle regeneration in patients with acute damage or muscular dystrophy. In this review, we summarize studies implicating cAMP signaling in skeletal muscle adaptation. We also highlight ligands that induce cAMP signaling and downstream effectors that are promising pharmacological targets.
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Affiliation(s)
- Rebecca Berdeaux
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA.
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18
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Qiao-bing H. Barrier stabilizing mediators in regulation of microvascular endothelial permeability. Chin J Traumatol 2012; 15. [PMID: 22480675 PMCID: PMC7129994 DOI: 10.3760/cma.j.issn.1008-1275.2012.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Increase of microvascular permeability is one of the most important pathological events in the pathogenesis of trauma and burn injury. Massive leakage of fluid from vascular space leads to lose of blood plasma and decrease of effective circulatory blood volume, resulting in formation of severe tissue edema, hypotension or even shock, especially in severe burn injury. Fluid resuscitation has been the only valid approach to sustain patient's blood volume for a long time, due to the lack of overall and profound understanding of the mechanisms of vascular hyperpermeability response. There is an emerging concept in recent years that some so-called barrier stabilizing mediators play a positive role in preventing the increase of vascular permeability. These mediators may be released in response to proinflammatory mediators and serve to restore endothelial barrier function. Some of these stabilizing mediators are important even in quiescent state because they preserve basal vascular permeability at low levels. This review introduces some of these mediators and reveals their underlying signaling mechanisms during endothelial barrier enhancing process.
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19
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Brown JA, Diggs-Andrews KA, Gianino SM, Gutmann DH. Neurofibromatosis-1 heterozygosity impairs CNS neuronal morphology in a cAMP/PKA/ROCK-dependent manner. Mol Cell Neurosci 2012; 49:13-22. [PMID: 21903164 PMCID: PMC3237958 DOI: 10.1016/j.mcn.2011.08.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 08/17/2011] [Accepted: 08/19/2011] [Indexed: 11/19/2022] Open
Abstract
Children with the neurofibromatosis-1 (NF1) cancer predisposition syndrome exhibit numerous clinical problems that reflect defective central nervous system (CNS) neuronal function, including learning disabilities, attention deficit disorder, and seizures. These clinical features result from reduced NF1 protein (neurofibromin) expression in NF1+/- (NF1 heterozygosity) brain neurons. Previous studies have shown that mouse CNS neurons are sensitive to the effects of reduced Nf1 expression and exhibit shorter neurite lengths, smaller growth cone areas, and attenuated survival, reflecting attenuated neurofibromin cAMP regulation. In striking contrast, Nf1+/- peripheral nervous system (PNS) neurons are nearly indistinguishable from their wild-type counterparts, and complete neurofibromin loss leads to increased neurite lengths and survival in a RAS/Akt-dependent fashion. To gain insights into the differential responses of CNS and PNS neurons to reduced neurofibromin function, we designed a series of experiments to define the molecular mechanism(s) underlying the unique CNS neuronal sensitivity to Nf1 heterozygosity. First, Nf1 heterozygosity decreases cAMP levels in CNS, but not in PNS, neurons. Second, CNS neurons exhibit Nf1 gene-dependent increases in RAS pathway signaling, but no further decreases in cAMP levels were observed in Nf1-/- CNS neurons relative to their Nf1+/- counterparts. Third, neurofibromin regulates CNS neurite length and growth cone areas in a cAMP/PKA/Rho/ROCK-dependent manner in vitro and in vivo. Collectively, these findings establish cAMP/PKA/Rho/ROCK signaling as the responsible axis underlying abnormal Nf1+/- CNS neuronal morphology with important implications for future preclinical and clinical studies aimed at improving cognitive and behavioral deficits in mice and children with reduced brain neuronal NF1 gene expression.
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Affiliation(s)
- Jacquelyn A Brown
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Kelly A Diggs-Andrews
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Scott M Gianino
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - David H Gutmann
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA.
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20
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Hu W, Lu T, Chen A, Huang Y, Hansen R, Chandler LJ, Zhang HT. Inhibition of phosphodiesterase-4 decreases ethanol intake in mice. Psychopharmacology (Berl) 2011; 218:331-9. [PMID: 21509503 PMCID: PMC4210373 DOI: 10.1007/s00213-011-2290-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2010] [Accepted: 03/29/2011] [Indexed: 01/29/2023]
Abstract
RATIONALE Cyclic AMP (cAMP)-protein kinase A signaling has been implicated in the regulation of ethanol consumption. Phosphodiesterase-4 (PDE4) specifically hydrolyzes cAMP and plays a critical role in controlling intracellular cAMP levels in the brain. However, the role of PDE4 in ethanol consumption remains unknown. OBJECTIVE The objective of this study is to examine whether PDE4 was involved in regulating ethanol intake. METHODS The two-bottle choice paradigm was used to assess intake of ethanol, sucrose, and quinine in C57BL/6J mice treated with the selective PDE4 inhibitor rolipram or Ro 20-1724; locomotor activity was also monitored using the open-field test in mice treated with rolipram. RESULTS Administration (i.p.) of either rolipram (0.25 and 0.5 mg/kg) or Ro 20-1724 (10 mg/kg) reduced ethanol intake and preference by 60-80%, but did not alter total fluid intake. In contrast, rolipram even at the higher dose of 0.5 mg/kg was not able to affect intake of sucrose or quinine, alcohol-induced sedation, or blood ethanol elimination. At 0.5 mg/kg, rolipram did decrease locomotor activity, but the effect only lasted for approximately 40 min, which did not likely affect behavior of ethanol drinking. CONCLUSIONS These results suggest that PDE4 is a novel target for drugs that reduce ethanol intake; PDE4 inhibitors may be used for treatment of alcohol dependence.
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Affiliation(s)
- Wei Hu
- Departments of Behavioral Medicine & Psychiatry and Physiology & Pharmacology, West Virginia University Health Sciences Center, Morgantown, WV26506, USA
| | - Tina Lu
- Departments of Behavioral Medicine & Psychiatry and Physiology & Pharmacology, West Virginia University Health Sciences Center, Morgantown, WV26506, USA
| | - Alan Chen
- Departments of Behavioral Medicine & Psychiatry and Physiology & Pharmacology, West Virginia University Health Sciences Center, Morgantown, WV26506, USA
| | - Ying Huang
- Departments of Behavioral Medicine & Psychiatry and Physiology & Pharmacology, West Virginia University Health Sciences Center, Morgantown, WV26506, USA
| | - Rolf Hansen
- Departments of Behavioral Medicine & Psychiatry and Physiology & Pharmacology, West Virginia University Health Sciences Center, Morgantown, WV26506, USA
| | - L. Judson Chandler
- Department of Neurosciences and Center for Drug and Alcohol Programs, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Han-Ting Zhang
- Departments of Behavioral Medicine & Psychiatry and Physiology & Pharmacology, West Virginia University Health Sciences Center, Morgantown, WV26506, USA
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21
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Puzhko S, Goodyer CG, Kerachian MA, Canaff L, Misra M, Jüppner H, Bastepe M, Hendy GN. Parathyroid hormone signaling via Gαs is selectively inhibited by an NH(2)-terminally truncated Gαs: implications for pseudohypoparathyroidism. J Bone Miner Res 2011; 26:2473-85. [PMID: 21713996 PMCID: PMC3916968 DOI: 10.1002/jbmr.461] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Pseudohypoparathyroid patients have resistance predominantly to parathyroid hormone (PTH), and here we have examined the ability of an alternative Gαs-related protein to inhibit Gαs activity in a hormone-selective manner. We tested whether the GNAS exon A/B-derived NH(2)-terminally truncated (Tr) αs protein alters stimulation of adenylate cyclase by the PTH receptor (PTHR1), the thyroid-stimulating hormone (TSH) receptor (TSHR), the β(2)-adrenergic receptor (β(2)AR), or the AVP receptor (V2R). HEK293 cells cotransfected with receptor and full-length (FL) Gαs ± Tr αs protein expression vectors were stimulated with agonists (PTH [10(-7) to 10(-9) M], TSH [1 to 100 mU], isoproterenol [10(-6) to 10(-8) M], or AVP [10(-6) to 10(-8) M]). Following PTH stimulation, HEK293 cells cotransfected with PTHR1 + FL Gαs + Tr αs had a significantly lower cAMP response than those transfected with only PTHR1 + FL Gαs. Tr αs also exerted an inhibitory effect on the cAMP levels stimulated by TSH via the TSHR but had little or no effect on isoproterenol or AVP acting via β(2)AR or V2R, respectively. These differences mimic the spectrum of hormone resistance in pseudohypoparathyroidism type 1a (PHP-1a) and type 1b (PHP-1b) patients. In opossum kidney (OK) cells, endogenously expressing the PTHR1 and β(2)AR, the exogenous expression of Tr αs at a level similar to endogenous FL Gαs resulted in blunting of the cAMP response to PTH, whereas that to isoproterenol was unaltered. A pseudopseudohypoparathyroid patient with Albright hereditary osteodystrophy harbored a de novo paternally inherited M1I Gαs mutation. Similar maternally inherited mutations at the initiation codon have been identified previously in PHP-1a patients. The M1I αs mutant (lacking the first 59 amino acids of Gαs) blunted the increase in cAMP levels stimulated via the PTHR1 in both HEK293 and OK cells similar to the Tr αs protein. Thus NH(2)-terminally truncated forms of Gαs may contribute to the pathogenesis of pseudohypoparathyroidism by inhibiting the activity of Gαs itself in a GPCR selective manner.
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Affiliation(s)
- Svetlana Puzhko
- Endocrine Research Laboratory, McGill University, Montreal, Quebec, Canada
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22
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Abstract
The role of Gβγ in adenylyl cyclase (AC) signaling is complicated due to its role as a conditional activator (AC2, AC4 and AC7) and an inhibitor (AC1, AC3 and AC8). AC2 is stimulated by Gα(s) and if Gβγ is present the stimulation is synergistic. The precise mechanism of this synergistic activation is still not known. In order to further elucidate the role of Gβγ in AC2 activation by Gα(s), peptides derived from the C1 domains of AC2 were synthesized and the ability of the various peptides to regulate AC2 function was tested. Our results identify two new Gβγ-binding sites in the AC2 C1 domain, AC2 C1a 339-360 and AC2 C1b 578-602 that are involved with stimulation of AC2 by Gβγ. These two regions are different from the previously described QEHA motif in the C2 domain of AC2. Further, the recently discovered PFAHL motif was confirmed to bind and to be involved with stimulation of AC2 by Gβγ. These functional studies indicate that multiple regions of AC2 are involved in the interaction with Gβγ.
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Affiliation(s)
- Aislyn D.W. Boran
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029 USA
| | - Yibang Chen
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029 USA
| | - Ravi Iyengar
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029 USA
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Nelson CP, Rainbow RD, Brignell JL, Perry MD, Willets JM, Davies NW, Standen NB, Challiss RJ. Principal role of adenylyl cyclase 6 in K⁺ channel regulation and vasodilator signalling in vascular smooth muscle cells. Cardiovasc Res 2011; 91:694-702. [PMID: 21606183 PMCID: PMC3156907 DOI: 10.1093/cvr/cvr137] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 05/06/2011] [Accepted: 05/12/2011] [Indexed: 02/07/2023] Open
Abstract
AIMS Membrane potential is a key determinant of vascular tone and many vasodilators act through the modulation of ion channel currents [e.g. the ATP-sensitive potassium channel (K(ATP))] involved in setting the membrane potential. Adenylyl cyclase (AC) isoenzymes are potentially important intermediaries in such vasodilator signalling pathways. Vascular smooth muscle cells (VSMCs) express multiple AC isoenzymes, but the reason for such redundancy is unknown. We investigated which of these isoenzymes are involved in vasodilator signalling and regulation of vascular ion channels important in modulating membrane potential. METHODS AND RESULTS AC isoenzymes were selectively depleted (by >75%) by transfection of cultured VSMCs with selective short interfering RNA sequences. AC6 was the predominant isoenzyme involved in vasodilator-mediated cAMP accumulation in VSMCs, accounting for ∼60% of the total response to β-adrenoceptor (β-AR) stimulation. AC3 played a minor role in β-AR signalling, whereas AC5 made no significant contribution. AC6 was also the principal isoenzyme involved in β-AR-mediated protein kinase A (PKA) signalling (determined using the fluorescent biosensor for PKA activity, AKAR3) and the substantial β-AR/PKA-dependent enhancement of K(ATP) current. K(ATP) current was shown to play a vital role in setting the resting membrane potential and in mediating the hyperpolarization observed upon β-AR stimulation. CONCLUSION AC6, but not the closely related AC5, plays a principal role in vasodilator signalling and regulation of the membrane potential in VSMCs. These findings identify AC6 as a vital component in the vasodilatory apparatus central to the control of blood pressure.
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Affiliation(s)
- Carl P. Nelson
- Department of Cell Physiology and Pharmacology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Richard D. Rainbow
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester LE2 7LX, UK
| | - Jennifer L. Brignell
- Department of Cell Physiology and Pharmacology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Matthew D. Perry
- Department of Cell Physiology and Pharmacology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Jonathon M. Willets
- Department of Cell Physiology and Pharmacology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, UK
- Department of Cancer Studies and Molecular Medicine, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester LE2 7LX, UK
| | - Noel W. Davies
- Department of Cell Physiology and Pharmacology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Nicholas B. Standen
- Department of Cell Physiology and Pharmacology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, UK
| | - R.A. John Challiss
- Department of Cell Physiology and Pharmacology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, UK
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Braunewell KH, Dwary AD, Richter F, Trappe K, Zhao C, Giegling I, Schönrath K, Rujescu D. Association of VSNL1 with schizophrenia, frontal cortical function, and biological significance for its gene product as a modulator of cAMP levels and neuronal morphology. Transl Psychiatry 2011; 1:e22. [PMID: 22832524 DOI: 10.1038/tp.2011.20] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
We report an association of single-nucleotide polymorphisms (SNPs) for the VSNL1 gene (visinin-like 1) with schizophrenia and frontal cortical function in a sample of patients with Diagnostic and Statistical Manual of Mental Disorder-IV (DSM-IV) diagnoses of schizophrenia, compared with healthy controls. Moreover, VSNL1 SNPs were associated with performance in the Wisconsin Card Sorting Test, a measure for the assessment of frontal cortical function. The VSNL1 gene product, Visinin-like-protein-1 (VILIP-1), is a member of the neuronal EF-hand Ca(2+)-sensor protein family. Previously, VILIP-1 mRNA and protein expression were shown to be altered in animal models and in schizophrenia patients. VILIP-1 influences cytosolic cyclic adenosine mono phosphate (cAMP) levels, cell migration, exocytotic processes and differentiation in the periphery. This raises the question, whether, similar to other potential schizophrenia susceptibility genes such as Disc1, PDE4B and Akt, VSNL1 may affect cAMP signaling and neurite outgrowth in neurons. In dissociated rat hippocampal neurons, VILIP-1 small interfering RNA knockdown decreased cAMP levels and reduced dendrite branching, compared with control-transfected cells. In contrast, VILIP-1 overexpression had the opposite effect. Similar results have been obtained in the human dopaminergic neuronal cell line SH-SY5Y, where the effect on neurite branching and length was attenuated by the adenylyl cyclase inhibitor 2',5'-dideoxyadenosine and the protein kinase A inhibitor KT5720. These results show that the association of VSNL1 SNPs with the disease and cognitive impairments, together with previously observed pathological changes in VILIP-1 protein expression, possibly occurring during brain development, may contribute to the morphological and functional deficits observed in schizophrenia.
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Abstract
Spiral ganglion neurons (SGNs) extend processes that interact with Schwann cells (SCs) and with oligodendrocytes (OLs) and astrocytes (ACs). We investigated the ability of these glial cells to support SGN neurite growth. In the presence of cultured ACs, OLs and SCs, SGN neurites tended to follow SCs and OLs and cross-over ACs. Most neurites initially followed the type of glial cell on which the neuronal cell body was found. To determine the influence of homogeneous populations of glia on neurite growth, SG explants were plated on cultured SCs, ACs or OLs. The number of neurites/explant extending onto SCs (463.89±16.25) was significantly greater than the number extending onto ACs (111.38±38.73) or OLs (6.75±2.21), indicating that populations of central glia inhibit SGN neurite growth. Treatment with cell-permeant cpt-cAMP or forskolin (FSK) each significantly increased the number of neurites on OLs (133.54±25.59 and 292.25±83.57, respectively). cpt-cAMP and FSK each also increased the number of neurites on ACs (213.19±36.06 and 208.64±59.25, respectively), however the difference was not significant compared with control. The neurites on ACs and OLs failed to grow radially in a well-fasciculated pattern as on SCs. In explants plated on the borders of cultured OL-SC or AC-SC groups, more neurites extended onto SCs compared with OLs and ACs. Conditioned media (CM) from OL or AC cultures did not reduce neurite length, implying that the inhibition of neurite growth by central glia is not due to soluble factors. Taken together, these results demonstrate that homogeneous populations of central glia inhibit SGN neurite growth.
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Affiliation(s)
- Eun-Ju Jeon
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa
- Department of Otolaryngology, Incheon St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea
| | - Ningyong Xu
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa
| | - Lingjing Xu
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa
| | - Marlan R. Hansen
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa
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Vilardaga JP, Romero G, Friedman PA, Gardella TJ. Molecular basis of parathyroid hormone receptor signaling and trafficking: a family B GPCR paradigm. Cell Mol Life Sci 2011; 68:1-13. [PMID: 20703892 PMCID: PMC3568769 DOI: 10.1007/s00018-010-0465-9] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 07/06/2010] [Accepted: 07/09/2010] [Indexed: 12/14/2022]
Abstract
The parathyroid hormone (PTH) receptor type 1 (PTHR), a G protein-coupled receptor (GPCR), transmits signals to two hormone systems-PTH, endocrine and homeostatic, and PTH-related peptide (PTHrP), paracrine-to regulate different biological processes. PTHR responds to these hormonal stimuli by activating heterotrimeric G proteins, such as G(S) that stimulates cAMP production. It was thought that the PTHR, as for all other GPCRs, is only active and signals through G proteins on the cell membrane, and internalizes into a cell to be desensitized and eventually degraded or recycled. Recent studies with cultured cell and animal models reveal a new pathway that involves sustained cAMP signaling from intracellular domains. Not only do these studies challenge the paradigm that cAMP production triggered by activated GPCRs originates exclusively at the cell membrane but they also advance a comprehensive model to account for the functional differences between PTH and PTHrP acting through the same receptor.
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Affiliation(s)
- Jean-Pierre Vilardaga
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Ozawa E. Regulation of phosphorylase kinase by low concentrations of Ca ions upon muscle contraction: the connection between metabolism and muscle contraction and the connection between muscle physiology and Ca-dependent signal transduction. Proc Jpn Acad Ser B Phys Biol Sci 2011; 87:486-508. [PMID: 21986313 PMCID: PMC3309122 DOI: 10.2183/pjab.87.486] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 08/25/2011] [Indexed: 05/31/2023]
Abstract
It had long been one of the crucial questions in muscle physiology how glycogenolysis is regulated in connection with muscle contraction, when we found the answer to this question in the last half of the 1960s. By that time, the two principal currents of muscle physiology, namely, the metabolic flow starting from glycogen and the mechanisms of muscle contraction, had already been clarified at the molecular level thanks to our senior researchers. Thus, the final question we had to answer was how to connect these two currents. We found that low concentrations of Ca ions (10(-7)-10(-4) M) released from the sarcoplasmic reticulum for the regulation of muscle contraction simultaneously reversibly activate phosphorylase kinase, the enzyme regulating glycogenolysis. Moreover, we found that adenosine 3',5'-monophosphate (cyclic AMP), which is already known to activate muscle phosphorylase kinase, is not effective in the absence of such concentrations of Ca ions. Thus, cyclic AMP is not effective by itself alone and only modifies the activation process in the presence of Ca ions (at that time, cyclic AMP-dependent protein kinase had not yet been identified). After a while, it turned out that our works have not only provided the solution to the above problem on muscle physiology, but have also been considered as the first report of Ca-dependent protein phosphorylation, which is one of the central problems in current cell biology. Phosphorylase kinase is the first protein kinase to phosphorylate a protein resulting in the change in the function of the phosphorylated protein, as shown by Krebs and Fischer. Our works further showed that this protein kinase is regulated in a Ca-dependent manner. Accordingly, our works introduced the concept of low concentrations of Ca ions, which were first identified as the regulatory substance of muscle contraction, to the vast field of Ca biology including signal transduction.
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Affiliation(s)
- Eijiro Ozawa
- National Center of Neuroscience, NCNP, Tokyo, Japan.
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28
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Adigun AA, Wrench N, Seidler FJ, Slotkin TA. Neonatal organophosphorus pesticide exposure alters the developmental trajectory of cell-signaling cascades controlling metabolism: differential effects of diazinon and parathion. Environ Health Perspect 2010; 118:210-5. [PMID: 20123610 PMCID: PMC2831919 DOI: 10.1289/ehp.0901237] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 09/24/2009] [Indexed: 05/17/2023]
Abstract
BACKGROUND Organophosphorus pesticides (OPs) are developmental neurotoxicants but also produce lasting effects on metabolism. OBJECTIVES/METHODS We administered diazinon (DZN) or parathion (PRT) to rats on postnatal days 14 at doses straddling the threshold for systemic signs of exposure and assessed the effects on hepatic and cardiac cell signaling mediated through the adenylyl cyclase (AC) cascade. RESULTS In the liver, DZN elicited global sensitization, characterized by parallel up-regulation of AC activity itself and of the responses to stimulants acting at beta-adrenergic receptors, glucagon receptors, or G-proteins. The effects intensified over the course from adolescence to adulthood. In contrast, PRT elicited up-regulation in adolescence that waned by adulthood. Superimposed on these general patterns were effects on glucagon receptor coupling to AC and on responses mediated through the Gi inhibitory protein. The effects on the liver were more substantial than those in the heart, which displayed only transient effects of DZN on AC function in adolescence and no significant effects of PRT. Furthermore, the hepatic effects were greater in magnitude than those in a brain region (cerebellum) that shares similar AC cascade elements. CONCLUSIONS These findings indicate that OPs alter the trajectory of hepatic cell signaling in a manner consistent with the observed emergence of prediabetes-like metabolic dysfunction. Notably, the various OPs differ in their net impact on peripheral AC signaling, making it unlikely that the effects on signaling reflect their shared property as cholinesterase inhibitors.
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Affiliation(s)
| | | | | | - Theodore A. Slotkin
- Address correspondence to T.A. Slotkin, Box 3813 DUMC, Duke University Medical Center, Durham, NC 27710 USA. Telephone: (919) 681-8015. Fax: (919) 684-8922. E-mail:
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Besschetnova TY, Kolpakova-Hart E, Guan Y, Zhou J, Olsen BR, Shah JV. Identification of signaling pathways regulating primary cilium length and flow-mediated adaptation. Curr Biol 2010; 20:182-7. [PMID: 20096584 PMCID: PMC2990526 DOI: 10.1016/j.cub.2009.11.072] [Citation(s) in RCA: 233] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2009] [Revised: 11/20/2009] [Accepted: 11/20/2009] [Indexed: 01/02/2023]
Abstract
The primary cilium acts as a transducer of extracellular stimuli into intracellular signaling [1, 2]. Its regulation, particularly with respect to length, has been defined primarily by genetic experiments and human disease states in which molecular components that are necessary for its proper construction have been mutated or deleted [1]. However, dynamic modulation of cilium length, a phenomenon observed in ciliated protists [3, 4], has not been well-characterized in vertebrates. Here we demonstrate that decreased intracellular calcium (Ca(2+)) or increased cyclic AMP (cAMP), and subsequent protein kinase A activation, increases primary cilium length in mammalian epithelial and mesenchymal cells. Anterograde intraflagellar transport is sped up in lengthened cilia, potentially increasing delivery flux of cilium components. The cilium length response creates a negative feedback loop whereby fluid shear-mediated deflection of the primary cilium, which decreases intracellular cAMP, leads to cilium shortening and thus decreases mechanotransductive signaling. This adaptive response is blocked when the autosomal-dominant polycystic kidney disease (ADPKD) gene products, polycystin-1 or -2, are reduced. Dynamic regulation of cilium length is thus intertwined with cilium-mediated signaling and provides a natural braking mechanism in response to external stimuli that may be compromised in PKD.
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Affiliation(s)
- Tatiana Y. Besschetnova
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - Elona Kolpakova-Hart
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Department of Oral and Developmental Biology, Harvard School of Dental Medicine, Boston, MA, USA
| | - Yinghua Guan
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - Jing Zhou
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - Bjorn R. Olsen
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Department of Oral and Developmental Biology, Harvard School of Dental Medicine, Boston, MA, USA
| | - Jagesh V. Shah
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
- Harvard-MIT Division of Health Sciences and Technology, Boston, MA, USA
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van der Plas MJA, Baldry M, van Dissel JT, Jukema GN, Nibbering PH. Maggot secretions suppress pro-inflammatory responses of human monocytes through elevation of cyclic AMP. Diabetologia 2009; 52:1962-70. [PMID: 19575178 PMCID: PMC2723663 DOI: 10.1007/s00125-009-1432-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Accepted: 06/02/2009] [Indexed: 12/26/2022]
Abstract
AIMS/HYPOTHESIS Maggots of the blowfly Lucilia sericata are used for the treatment of chronic wounds. As monocytes may contribute to the excessive inflammatory responses in such wounds, this study focussed on the effects of maggot secretions on the pro-inflammatory activities of these cells. METHODS Freshly isolated monocytes were incubated with a range of secretions for 1 h and then stimulated with lipopolysaccharides (range 0-100 ng/ml) or lipoteichoic acid (range 0-5 microg/ml) for 18 h. The expression of cell surface molecules, cytokine and chemokine levels in culture supernatants, cell viability, chemotaxis, and phagocytosis and killing of Staphylococcus aureus were measured. RESULTS Maggot secretions dose-dependently inhibited production of the pro-inflammatory cytokines TNF-alpha, IL-12p40 and macrophage migration inhibitory factor by lipopolysaccharides- and lipoteichoic acid-stimulated monocytes, while enhancing production of the anti-inflammatory cytokine IL-10. Expression of cell surface receptors involved in pathogen recognition remained unaffected by secretions. In addition, maggot secretions altered the chemokine profile of monocytes by downregulating macrophage inflammatory protein-1beta and upregulating monocyte chemoattractant protein-1 and IL-8. Nevertheless, chemotactic responses of monocytes were inhibited by secretions. Furthermore, maggot secretions did not affect phagocytosis and intracellular killing of S. aureus by human monocytes. Finally, secretions induced a transient rise in the intracellular cyclic AMP concentration in monocytes and Rp-cyclic AMPS inhibited the effects of secretions. CONCLUSIONS/INTERPRETATION Maggot secretions inhibit the pro-inflammatory responses of human monocytes through a cyclic AMP-dependent mechanism. Regulation of the inflammatory processes by maggots contributes to their beneficial effects on chronic wounds.
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Affiliation(s)
- M. J. A. van der Plas
- Department of Infectious Diseases, C5-P, Leiden University Medical Center (LUMC), Albinusdreef 2, PO Box 9600, 2300 RC Leiden, the Netherlands
- Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands
| | - M. Baldry
- Department of Infectious Diseases, C5-P, Leiden University Medical Center (LUMC), Albinusdreef 2, PO Box 9600, 2300 RC Leiden, the Netherlands
| | - J. T. van Dissel
- Department of Infectious Diseases, C5-P, Leiden University Medical Center (LUMC), Albinusdreef 2, PO Box 9600, 2300 RC Leiden, the Netherlands
| | - G. N. Jukema
- Department of Trauma Surgery, Free University Medical Center, Amsterdam, the Netherlands
| | - P. H. Nibbering
- Department of Infectious Diseases, C5-P, Leiden University Medical Center (LUMC), Albinusdreef 2, PO Box 9600, 2300 RC Leiden, the Netherlands
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Lakshminrusimha S, Porta NF, Farrow KN, Chen B, Gugino SF, Kumar VH, Russell JA, Steinhorn RH. Milrinone enhances relaxation to prostacyclin and iloprost in pulmonary arteries isolated from lambs with persistent pulmonary hypertension of the newborn. Pediatr Crit Care Med 2009; 10:106-12. [PMID: 19057444 DOI: 10.1097/PCC.0b013e3181936aee] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
UNLABELLED Prostacyclin is a pulmonary vasodilator and is produced by prostacyclin synthase and stimulates adenylate cyclase (AC) via the prostacyclin receptor (IP) to produce cAMP. Forskolin is a direct stimulant of AC. Phosphodiesterase 3 hydrolyzes cAMP and is inhibited by milrinone. OBJECTIVE To characterize the prostacyclin-AC-cAMP pathway in the ovine ductal ligation model of persistent pulmonary hypertension of the newborn (PPHN). SETTING University-based laboratory animal facility. SUBJECTS Lambs delivered to time-dated pregnant ewes. INTERVENTIONS Fifth generation pulmonary arteries (PA) and lung parenchyma were isolated from control fetal lambs (n = 8) and fetal lambs with PPHN induced by antenatal ductal ligation (n = 9). We studied relaxation responses to various agonists (milrinone, forskolin, prostacyclin, and iloprost, a prostacyclin analog) that increase cAMP in PA after half-maximal constriction with norepinephrine and pretreatment with propranolol +/- indomethacin. Lung protein levels of prostacyclin synthase, IP, AC2, and phosphodiesterase 3A were analyzed by Western blot and cAMP by enzyme-linked immunoassay. MAIN RESULTS Milrinone relaxed control and PPHN PA and pretreatment with indomethacin significantly impaired this response. Relaxation to milrinone, prostacyclin, and iloprost were significantly impaired in PA from PPHN lambs. Pretreatment with milrinone markedly enhanced relaxation to prostacyclin and iloprost in PPHN PA, similar to relaxation in control PA. Relaxation to forskolin was similar in control and PPHN PAs indicating normal AC activity. Protein levels of prostacyclin synthase and IP were decreased in PPHN lungs compared with control, but AC2, cAMP, and phosphodiesterase 3A remained unchanged. CONCLUSIONS Prostacyclin and iloprost are dilators of PAs from PPHN lambs and their effect is enhanced by milrinone. This combination therapy may be an effective strategy in the management of patients with PPHN.
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Abstract
A patent ductus arteriosus is due in large part to increased sensitivity of the premature ductus to PGE2. After PGE2 stimulation, cAMP concentrations are higher in the immature than in the mature ductus. cAMP concentrations depend on the rates of adenyl cyclase production and phosphodiesterase (PDE)-mediated degradation. We used ductus from immature (n = 25) and mature (n = 21) fetal sheep to investigate whether a developmental increase in PDE activity could explain the diminished cAMP accumulation that follows PGE2 stimulation in the mature ductus. With advancing gestation, mRNA expression of the smooth muscle PDE isoforms (PDE1A, 1B, 1C, 3A, 3B, 4D, and 5A) increased in the ductus as did their hydrolytic activities. Selective inhibitors of PDE1, PDE3, and PDE4 relaxed the mature and immature ductus in the presence of inhibitors of prostaglandin and nitric oxide production. The mature ductus required higher concentrations of each of the PDE inhibitors to inhibit its tension to the same extent as in the immature ductus. There were no developmental changes in PDE expression in the fetal aorta. In conclusion, we observed a developmental increase in cAMP and cGMP PDE activity that contributes to the decreased sensitivity of the late-gestation ductus arteriosus to vasodilators like PGE2.
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Affiliation(s)
- Hanguan Liu
- Laboratory of Cellular Metabolism, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892, USA
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Abstract
cAMP-mediated signaling pathways regulate a multitude of important biological processes under both physiological and pathological conditions, including diabetes, heart failure and cancer. In eukaryotic cells, the effects of cAMP are mediated by two ubiquitously expressed intracellular cAMP receptors, the classic protein kinase A (PKA)/cAMP-dependent protein kinase and the recently discovered exchange protein directly activated by camp (Epac)/cAMP-regulated guanine nucleotide exchange factors. Like PKA, Epac contains an evolutionally conserved cAMP binding domain that acts as a molecular switch for sensing intracellular second messenger cAMP levels to control diverse biological functions. The existence of two families of cAMP effectors provides a mechanism for a more precise and integrated control of the cAMP signaling pathways in a spatial and temporal manner. Depending upon the specific cellular environments as well as their relative abundance, distribution and localization, Epac and PKA may act independently, converge synergistically or oppose each other in regulating a specific cellular function.
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Affiliation(s)
- Xiaodong Cheng
- Department of Pharmacology and Toxicology, Sealy Center for Cancer Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555-1031, USA.
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Boikos SA, Horvath A, Heyerdahl S, Stein E, Robinson-White A, Bossis I, Bertherat J, Carney JA, Stratakis CA. Phosphodiesterase 11A expression in the adrenal cortex, primary pigmented nodular adrenocortical disease, and other corticotropin-independent lesions. Horm Metab Res 2008; 40:347-53. [PMID: 18491255 PMCID: PMC2713062 DOI: 10.1055/s-2008-1076694] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A variety of adrenal tumors and bilateral adrenocortical hyperplasias (BAH) leading to Cushing syndrome (CS) may be caused by aberrant cAMP signaling. We recently identified patients with a micronodular form of BAH that we have called "isolated micronodular adrenocortical disease" (iMAD) in whom CS was associated with inactivating mutations in phosphodiesterase (PDE) 11A ( PDE11A). In the present study, we examined PDE11A expression in normal adrenocortical tissue, sporadic tumors, and hyperplasias without PDE11A mutations, and primary pigmented nodular adrenocortical disease (PPNAD) and adenomas from patients with PRKAR1A and a single tumor with a GNAS mutation. The total number of the tumor samples that we studied was 22. Normal human tissues showed consistent PDE11A expression. There was variable expression of PDE11A in sporadic adrenocortical hyperplasia or adenomas; PPNAD tissues from patients with PRKAR1A mutations expressed consistently high levels of PDE11A in contrast to adenomas caused by GNAS mutations. Phosphorylated CREB was the highest in tissues from patients with iMAD compared to all other forms of BAH and normal adrenal tissue. We conclude that PDE11A is expressed widely in adrenal cortex. Its expression appears to be increased in PPNAD but varies widely among other adrenocortical tumors. PRKAR1A expression appears to be higher in tissues with PDE11A defects. Finally, sequencing defects in PDE11A are associated with a high state of CREB phosphorylation, just like PRKAR1A mutations. These preliminary data suggest that these two molecules are perhaps regulated in a reverse manner in their control of cAMP signaling in adrenocortical tissues.
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Affiliation(s)
- S. A. Boikos
- Section on Endocrinology & Genetics, Program on Developmental Endocrinology & Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - A. Horvath
- Section on Endocrinology & Genetics, Program on Developmental Endocrinology & Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - S. Heyerdahl
- Section on Endocrinology & Genetics, Program on Developmental Endocrinology & Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - E. Stein
- Section on Endocrinology & Genetics, Program on Developmental Endocrinology & Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - A. Robinson-White
- Section on Endocrinology & Genetics, Program on Developmental Endocrinology & Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - I. Bossis
- Section on Endocrinology & Genetics, Program on Developmental Endocrinology & Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - J. Bertherat
- INSERM U567 and Institut Cochin, Assistance Publique H ôpitaux de Paris, Hô pital Cochin, Department of Endocrinology, Reference Center for Rare Adrenal Diseases, Paris, France
| | - J. A. Carney
- Laboratory of Pathology, Mayo Clinic, Rochester, MN, USA
| | - C. A. Stratakis
- Section on Endocrinology & Genetics, Program on Developmental Endocrinology & Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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Rutten K, Basile JL, Prickaerts J, Blokland A, Vivian JA. Selective PDE inhibitors rolipram and sildenafil improve object retrieval performance in adult cynomolgus macaques. Psychopharmacology (Berl) 2008; 196:643-8. [PMID: 18034336 PMCID: PMC2244695 DOI: 10.1007/s00213-007-0999-1] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Accepted: 10/23/2007] [Indexed: 11/29/2022]
Abstract
RATIONALE Selective phosphodiesterase (PDE) inhibitors improve the formation of hippocampus-dependent memories in several rodent models of cognition. However, studies evaluating the effects of PDE inhibition on prefrontal cortex-dependent cognition and in monkeys are rare. OBJECTIVES The present study investigates the effect of the PDE4 inhibitor rolipram and the PDE5 inhibitor sildenafil on object retrieval performance. Object retrieval is a prefrontal cortical-mediated task, which is likely to capture attention and response inhibition. MATERIALS AND METHODS The ability to retrieve a food reward from a clear box with an open side positioned in various orientations was assessed in adult male cynomolgus monkeys (Macaca fascicularis). RESULTS Rolipram (0.003-0.03 mg/kg, intramuscular [i.m.]) and sildenafil (0.3-3 mg/kg, i.m.) dose-dependently increased correct first reaches during difficult trials, reaching significance at 0.01 and 1 mg/kg, respectively. For both drugs, correct reaches were increased approximately 20%; that is, performance was improved from approximately 50 to approximately 70% correct. CONCLUSIONS Both rolipram and sildenafil improved object retrieval performance, thus demonstrating the cognition-enhancing effects of PDE inhibition on a prefrontal task of executive function in monkeys.
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Affiliation(s)
- K. Rutten
- Department of Neuroscience, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands ,Department of Neuroscience, Roche Pharmaceuticals Palo Alto, Palo Alto, CA USA
| | - J. L. Basile
- Department of Neuroscience, Roche Pharmaceuticals Palo Alto, Palo Alto, CA USA
| | - J. Prickaerts
- Department of Neuroscience, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands ,Department of Neuropsychology and Psychopharmacology, Maastricht University, Maastricht, The Netherlands
| | - A. Blokland
- Department of Neuropsychology and Psychopharmacology, Maastricht University, Maastricht, The Netherlands
| | - J. A. Vivian
- Department of Neuroscience, Roche Pharmaceuticals Palo Alto, Palo Alto, CA USA
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Carlson AE, Hille B, Babcock DF. External Ca2+ acts upstream of adenylyl cyclase SACY in the bicarbonate signaled activation of sperm motility. Dev Biol 2007; 312:183-92. [PMID: 17950270 PMCID: PMC2259292 DOI: 10.1016/j.ydbio.2007.09.017] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 09/06/2007] [Accepted: 09/10/2007] [Indexed: 12/18/2022]
Abstract
The HCO3(-) anion activates sperm motility, an important early step in capacitation, by increasing flagellar beat frequency through a pathway that requires the atypical adenylyl cyclase SACY and the sperm-specific C alpha2 catalytic subunit of PKA. Here we show that the accelerating action of HCO3(-) also requires the continued presence of external Ca2+ (EC50 approximately 0.5 mM), and find that Ca2+ can be replaced by Sr2+ but not by Mn2+. Ca2+ is required for HCO3(-) to elevate cAMP, but not for cAMP-AM to increase beat frequency, indicating that external Ca2+ acts before rather than after stimulation of SACY by HCO3(-). With external Ca2+ present, HCO3(-) does not alter cytosolic or near-membrane [Ca2+]. Removal of external Ca2+ initiates a slow decline in intracellular [Ca2+] and rapid block of the HCO3(-)-evoked acceleration that is not relieved upon increasing internal [Ca2+] by rapid photolysis of caged Ca2+. We also find that the rapid (t(1/2) approximately 10 s) accelerating action of HCO3(-) is slowed more than three-fold by the carbonic anhydrase inhibitor acetazolamide. It is unaltered by the broad spectrum anion transport inhibitor SITS, and is not accompanied by detectable changes in intracellular pH. We propose that external Ca2+ binds an unidentified extracellular protein that is required for HCO3(-) to engage cAMP-mediated activation of motility.
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Affiliation(s)
- Anne E. Carlson
- Department of Physiology and Biophysics, Box 357290, University of Washington, Seattle, WA 98195 USA
| | - Bertil Hille
- Department of Physiology and Biophysics, Box 357290, University of Washington, Seattle, WA 98195 USA
| | - Donner F. Babcock
- Department of Physiology and Biophysics, Box 357290, University of Washington, Seattle, WA 98195 USA
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Rutten K, Lieben C, Smits L, Blokland A. The PDE4 inhibitor rolipram reverses object memory impairment induced by acute tryptophan depletion in the rat. Psychopharmacology (Berl) 2007; 192:275-82. [PMID: 17265077 PMCID: PMC1915617 DOI: 10.1007/s00213-006-0697-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Accepted: 12/28/2006] [Indexed: 10/27/2022]
Abstract
RATIONALE The selective type IV phosphodiesterase inhibitor, rolipram, has been shown to improve long-term memory and can reverse the cholinergic deficit caused by scopolamine. However, the underlying mechanisms of action of rolipram remain obscure. OBJECTIVES The present study investigates the effect of rolipram in a serotonergic-deficit model of acute tryptophan depletion (ATD). In addition, the levels of plasma tryptophan (TRP) were compared to object recognition performance. MATERIALS AND METHODS The experiments were conducted using male Wistar rats. The time-dependent effect of ATD treatment (a gelatin-based protein mixture) on plasma TRP levels (0, 1, 3, and 6 h after injection) and object recognition task (ORT) performance (0.5, 1, 3, and 6 h after ATD treatment) was examined. The effect of rolipram (0, 0.01, 0.03, and 0.1 mg/kg, i.p.) was tested in the condition in which ATD induced a clear memory deficit. RESULTS ATD significantly lowered the plasma TRP ratio (TRP/Sigmalarge neutral amino acid) with a maximum of 48%, approximately 1 h after administration. Furthermore, ATD impairs ORT performance when administered 3 h before testing. Rolipram (0.1 mg/kg) reversed the memory deficit induced by ATD in a dose-dependent manner. CONCLUSIONS On the basis of previous studies and the ability to reverse a serotonergic deficit, we suggest that rolipram may act through elevation of cyclic adenosine monophosphate levels and subsequent increase in neurotransmitter release.
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Affiliation(s)
- K Rutten
- Department of Psychiatry and Neuropsychology, Brain and Behavior Institute, Maastricht University, Universiteitssingel 50, 6200 MD, Maastricht, The Netherlands.
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Kolla V, Gonzales LW, Gonzales J, Wang P, Angampalli S, Feinstein SI, Ballard PL. Thyroid transcription factor in differentiating type II cells: regulation, isoforms, and target genes. Am J Respir Cell Mol Biol 2007; 36:213-25. [PMID: 16960125 PMCID: PMC1899316 DOI: 10.1165/rcmb.2006-0207oc] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Accepted: 08/18/2006] [Indexed: 11/24/2022] Open
Abstract
Thyroid transcription factor-1 (TTF-1, product of the Nkx2.1 gene) is essential for branching morphogenesis of the lung and enhances expression of surfactant proteins by alveolar type II cells. We investigated expression of two TTF-1 mRNA transcripts, generated by alternative start sites and coding for 42- and 46-kD protein isoforms in the mouse, during hormone-induced differentiation of human fetal lung type II cells in culture. Transcript for 42-kD TTF-1 was 20-fold more abundant than TTF-1(46) mRNA by RT-PCR. Only 42-kD protein was detected in lung cells, and its content increased during in vivo development and in response to in vitro glucocorticoid plus cAMP treatment. To examine TTF-1 target proteins, recombinant, phosphorylated TTF-1(42) was expressed in nuclei of cells by adenovirus transduction. By microarray analysis, 14 genes were comparably induced by recombinant TTF-1 (rTTF-1) and hormone treatment, and 9 additional hormone-responsive genes, including surfactant proteins-A/B/C, were partially induced by rTTF-1. The most highly (approximately 10-fold) TTF-1-induced genes were DC-LAMP (LAMP3) and CEACAM6 with induction confirmed by Western analysis and immunostaining. Treatment of cells with hormones plus small inhibitory RNA directed toward TTF-1 reduced TTF-1 content by approximately 50% and inhibited hormone induction of the 23 genes induced by rTTF-1. In addition, knockdown of TTF-1 inhibited 72 of 274 other genes induced by hormones. We conclude that 42-kD TTF-1 is required for induction of a subset of regulated genes during type II cell differentiation.
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Affiliation(s)
- Venkatadri Kolla
- Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, USA
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Devaki R, Shankar Rao S, Nadgir SM. The effect of lithium on the adrenoceptor-mediated second messenger system in the rat brain. J Psychiatry Neurosci 2006; 31:246-52. [PMID: 16862242 PMCID: PMC1488903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
OBJECTIVE Lithium remains the most widely used treatment for bipolar disorder; however, the molecular mechanisms underlying its therapeutic actions have not been fully elucidated. We studied the in-vivo effect of lithium on the density of alpha-adrenoceptor (alpha-AR) and beta-AR subtypes and linked second messenger systems in the rat brain. METHODS The densities of alpha(1)-ARs, alpha(2)-ARs, and beta(1)-ARs and beta(2)-ARs in the cortex and cerebellum of rats treated with lithium (0.4%), orally, for 30 days were measured using [(3)H]prazosin, [(3)H]clonidine and [(3)H]CGP-12177, respectively. The activity of adenylyl cyclase (AC) and levels of inositol trisphosphate (IP3), both second messengers linked to these receptors, were estimated using [(3)H]ATP and [(3)H]myoinositol, respectively. RESULTS A significant decrease in the densities of cortical alpha(1)-ARs (85%, p < 0.0001), alpha(2)-ARs (50%, p < 0.0001), beta(1)-ARs (26%, p < 0.0001) and beta(2)-ARs (25%, p < 0.0001) was observed after lithium treatment. However, only the density of alpha(1)-ARs was significantly decreased (25%, p < 0.0001) in the cerebellum. The affinity of [(3)H]prazosin for cerebellar alpha(1)-ARs was increased. A small, but statistically significant, increase (19%, p < 0.0001) in the density of total beta-ARs was seen in the cerebellum, without altering the affinity of the radioligand for these receptors. Basal AC activity was not altered in the lithium-treated rat cortex. However, the norepinephrine-stimulated AC activity, which represents alpha(2)-AR-linked and beta-AR-linked AC, was significantly increased (66%, p < 0.0001). Both basal IP3 formation and norepinephrine-stimulated IP3, which represents alpha(1)-AR-linked phospholipase C activity, were significantly decreased (50%, p < 0.0001) in the lithium-treated rat cortex. CONCLUSION Our results suggest that long-term administration of lithium treatment downregulates the cortical, but not cerebellar, alpha(1)-ARs, alpha(2)-ARs, beta(1)-ARs and beta(2)-ARs. Thus, it may be concluded that lithium induces region-specific and differential functional downregulation of alpha-AR and beta-AR subtypes in the rat brain.
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Affiliation(s)
- Ramakrishna Devaki
- Department of Neurochemistry, National Institute of Mental Health and Neurosciences, Bangalore-560 029, India
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Wade KC, Guttentag SH, Gonzales LW, Maschhoff KL, Gonzales J, Kolla V, Singhal S, Ballard PL. Gene induction during differentiation of human pulmonary type II cells in vitro. Am J Respir Cell Mol Biol 2006; 34:727-37. [PMID: 16474099 PMCID: PMC2644235 DOI: 10.1165/rcmb.2004-0389oc] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Accepted: 01/27/2006] [Indexed: 11/24/2022] Open
Abstract
Mature alveolar type II cells that produce pulmonary surfactant are essential for adaptation to extrauterine life. We profiled gene expression in human fetal lung epithelial cells cultured in serum-free medium containing dexamethasone and cyclic AMP, a treatment that induces differentiation of type II cells. Microarray analysis identified 388 genes that were induced > 1.5-fold by 72 h of hormone treatment. Induced genes represented all categories of molecular function and subcellular location, with increased frequency in the categories of ionic channel, cell adhesion, surface film, lysosome, extracellular matrix, and basement membrane. In time-course experiments, self-organizing map analysis identified a cluster of 17 genes that were slowly but highly induced (5- to approximately 190-fold) and represented four functional categories: surfactant-related (SFTPC, SFTPA, PGC, SFTPB, LAMP3, LPL), regulatory (WIF2, IGF2, IL1RL1, NR4A2, HIF3A), metabolic (MAOA, ADH1B, SEPP1), and transport (SCNN1A, CLDN18, AQP4). Induction of both mRNA and protein for these genes, which included nine newly identified regulated genes, was confirmed, and cellular localization was determined in both fetal and postnatal tissue. Induction of lysosomal-associated membrane protein 3 required both hormones, and expression was localized to limiting membranes of lamellar bodies. Hormone-induced differentiation of human type II cells is associated with genome-wide increased expression of genes with diverse functions.
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Affiliation(s)
- Kelly C Wade
- Department of Pediatrics, Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
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Li XC, Carretero OA, Shao Y, Zhuo JL. Glucagon receptor-mediated extracellular signal-regulated kinase 1/2 phosphorylation in rat mesangial cells: role of protein kinase A and phospholipase C. Hypertension 2006; 47:580-5. [PMID: 16391176 PMCID: PMC2367309 DOI: 10.1161/01.hyp.0000197946.81754.0a] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Glucagon, a major insulin counterregulatory hormone, binds to specific Gs protein-coupled receptors to activate glycogenolytic and gluconeogenic pathways, causing blood glucose levels to increase. Inappropriate increases in serum glucagon play a critical role in the development of insulin resistance and target organ damage in type 2 diabetes. We tested the hypotheses that: (1) glucagon induces proliferation of rat glomerular mesangial cells through glucagon receptor-activated phosphorylation of mitogen-activated protein kinase extracellular signal-regulated kinase 1/2 (p-ERK 1/2); and (2) this phosphorylation involves activation of cAMP-dependent protein kinase A (PKA) and phospholipase C (PLC)/[Ca2+]i signaling pathways. In rat mesangial cells, glucagon (1 nM) stimulated [3H]-thymidine incorporation by 96% (P<0.01). This proliferative effect was blocked by the specific glucagon receptor antagonist [Des-His1-Glu9] glucagon (1 micromol/L; P<0.01), a mitogen-activated protein kinase/ERK kinase inhibitor PD98059 (10 micromol/L; P<0.01), a PLC inhibitor U73122 (1 micromol/L; P<0.01), or a PKA inhibitor H-89 (1 micromol/L; P<0.01). The proliferation was associated with a 2-fold increase in p-ERK 1/2 that peaked 5 minutes after glucagon stimulation (P<0.01) and also was blocked by [Des-His1-Glu9] glucagon. Total ERK 1/2 was not affected by glucagon. Pretreating of mesangial cells with U73122 or H89 significantly attenuated ERK 1/2 phosphorylation induced by glucagon. We believe that these are the first data showing that glucagon activates specific receptors to induce ERK 1/2 phosphorylation and thereby increase mesangial cell proliferation and that this effect of glucagon involves both PLC/[Ca2+]i- and cAMP-dependent PKA-activated signaling cascades.
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Affiliation(s)
- Xiao C Li
- Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI 48202, USA
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Abstract
This article provides a brief and somewhat personalized review of the dramatic developments that have occurred over the last 45 years in our understanding of intracellular signalling pathways associated with G-protein-coupled receptor activation. Signalling via cyclic AMP, the phosphoinositides and Ca(2+) is emphasized and these systems have already been revealed as new pharmacological targets. The therapeutic benefits of most of such targets are, however, yet to be realized, but it is certain that the discipline of pharmacology needs to widen its boundaries to meet these challenges in the future.
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Affiliation(s)
- Stefan R Nahorski
- Department of Cell Physiology and Pharmacology, University of Leicester, Medical Sciences Building, University Road, Leicester LE1 9HN.
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Abstract
Phosphodiesterase (PDE) 4 inhibitors have been shown to induce the cAMP-mediated signaling pathway by inhibiting cAMP hydrolysis. This study investigated the effect of a PDE4 inhibitor on the expression of the inducible cAMP early repressor (ICER), which is an endogenous inhibitor of CRE- mediated transcription, in osteoblastic cells. RT-PCR analysis revealed that rolipram, a PDE4 inhibitor, stimulates the ICER mRNA in a dose dependent manner. The induction of ICER mRNA expression by rolipram was suppressed by the inhibitors of protein kinase A (PKA) and p38 MAPK, suggesting the involvement of PKA and p38 MAPK activation in ICER expression by rolipram. It was previously shown that rolipram induced the expression of TNF-related activation-induced cytokine (TRANCE, also known as RANKL, ODF, or OPGL) in osteoblasts. This paper provides evidences that a transcriptional repressor like ICER might modulate TRANCE mRNA expression by rolipram in osteoblasts.
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Affiliation(s)
- Eun Sook Cho
- College of Pharmacy, Sookmyung Women's University, Seoul, Korea
| | - Ja Heon Yu
- College of Pharmacy, Sookmyung Women's University, Seoul, Korea
| | - Mi Sun Kim
- College of Pharmacy, Sookmyung Women's University, Seoul, Korea
| | - Mijung Yim
- College of Pharmacy, Sookmyung Women's University, Seoul, Korea
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Lee JM, Caturegli P, Ladenson PW. Theophylline increases the uptake of radioiodine by mouse thyroid. J Korean Med Sci 2004; 19:704-9. [PMID: 15483348 PMCID: PMC2816335 DOI: 10.3346/jkms.2004.19.5.704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Diagnostic and therapeutic use of radioiodine in the management of thyroid disorders depends on the ability of thyroid cells to concentrate radioiodine, a process that is regulated by the intracellular increase in cAMP. We hypothesized that theophylline, a drug known to increase intracellular cAMP via inhibition of phosphodiesterase, could increase thyroidal radioiodine uptake. We tested this effect in vivo, using C57BL/6j mice, and in vitro, using Fisher rat thyroid (FRTL-5) cells. One mouse received 2.5mg theophylline i.p., whereas a control mouse received only saline. Twenty-hours after theophylline, mice were injected with 10 microCi Na125I in 0.1 mL saline through the tail vein. Mean thyroidal 125I activity was 3.3-fold higher in theophylline-treated mice than in their respective controls. Radioiodine uptake and intracellular cAMP production of FRTL-5 cells were increased by a relatively low concentration of theophylline (1 microM). Intracellular cAMP increased up to 30 min and then declined in response to 1 microM theophylline. Sera from theophylline-treated mice stimulated 125I uptake and intracellular cAMP production by FRTL-5 cells. These findings show that theophylline can enhance radioiodine uptake by thyrocytes in vivo and in vitro. The in vitro effects of theophylline on both radioiodine uptake and cAMP production in a dose-dependent manner are consistent with an action mediated by phosphodiesterase inhibition.
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Affiliation(s)
- Jong Min Lee
- Department of Internal Medicine, The Catholic University of Korea, Medical College, Seoul, Korea.
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Ohno M, Gao ZG, Van Rompaey P, Tchilibon S, Kim SK, Harris BA, Gross AS, Duong HT, Van Calenbergh S, Jacobson KA. Modulation of adenosine receptor affinity and intrinsic efficacy in adenine nucleosides substituted at the 2-position. Bioorg Med Chem 2004; 12:2995-3007. [PMID: 15142558 PMCID: PMC3463103 DOI: 10.1016/j.bmc.2004.03.031] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Revised: 03/01/2004] [Accepted: 03/14/2004] [Indexed: 11/18/2022]
Abstract
We studied the structural determinants of binding affinity and efficacy of adenosine receptor (AR) agonists. Substituents at the 2-position of adenosine were combined with N(6)-substitutions known to enhance human A(3)AR affinity. Selectivity of binding of the analogues and their functional effects on cAMP production were studied using recombinant human A(1), A(2A), A(2B), and A(3)ARs. Mainly sterically small substituents at the 2-position modulated both the affinity and intrinsic efficacy at all subtypes. The 2-cyano group decreased hA(3)AR affinity and efficacy in the cases of N(6)-(3-iodobenzyl) and N(6)-(trans-2-phenyl-1-cyclopropyl), for which a full A(3)AR agonist was converted into a selective antagonist; the 2-cyano-N(6)-methyl analogue was a full A(3)AR agonist. The combination of N(6)-benzyl and various 2-substitutions (chloro, trifluoromethyl, and cyano) resulted in reduced efficacy at the A(1)AR. The environment surrounding the 2-position within the putative A(3)AR binding site was explored using rhodopsin-based homology modeling and ligand docking.
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Affiliation(s)
- Michihiro Ohno
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), DHHS, Bldg. 8A, Rm. B1A-19, NIH, NIDDK, LBC, Bethesda, MD 20892-0810, USA
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Abstract
The parasympathetic component of the autonomic nervous system plays an important role in the physiological regulation of cardiac function by exerting significant influence over the initiation as well as propagation of electrical impulses, in addition to being able to regulate contractile force. These effects are mediated in whole or in part through changes in ion channel activity that occur in response to activation of M(2) muscarinic cholinergic receptors following release of the neurotransmitter acetylcholine. The coupling of M(2) receptor activation to most changes in cardiac ion channel function can be explained by one of two general paradigms. The first involves direct G protein-dependent regulation of ion channel activity. The second involves indirect regulation of ion channel activity through modulation of cAMP-dependent responses. This review focuses on recent advances in our understanding of the mechanisms by which M(2) muscarinic receptor activation both inhibits and facilitates cAMP-dependent ion channel responses in the heart.
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Affiliation(s)
- Robert D Harvey
- Department of Physiology and Biophysics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-4970, U.S.A.
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Gao ZG, Blaustein JB, Gross AS, Melman N, Jacobson KA. N6-Substituted adenosine derivatives: selectivity, efficacy, and species differences at A3 adenosine receptors. Biochem Pharmacol 2003; 65:1675-84. [PMID: 12754103 PMCID: PMC3142561 DOI: 10.1016/s0006-2952(03)00153-9] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The activation of the human A(3) adenosine receptor (AR) by a wide range of N(6)-substituted adenosine derivatives was studied in intact CHO cells stably expressing this receptor. Selectivity of binding at rat and human ARs was also determined. Among N(6)-alkyl substitutions, small N(6)-alkyl groups were associated with selectivity for human A(3)ARs vs. rat A(3)ARs, and multiple points of branching were associated with decreased hA(3)AR efficacy. N(6)-Cycloalkyl-substituted adenosines were full (</=5 carbons) or partial (>/=6 carbons) hA(3)AR agonists. N(6)-(endo-Norbornyl)adenosine 13 was the most selective for both rat and human A(1)ARs. Numerous N(6)-arylmethyl analogues, including substituted benzyl, tended to be more potent in binding to A(1) and A(3) vs. A(2A)ARs (with variable degrees of partial to full A(3)AR agonisms). A chloro substituent decreased the efficacy depending on its position on the benzyl ring. The A(3)AR affinity and efficacy of N(6)-arylethyl adenosines depended highly on stereochemistry, steric bulk, and ring constraints. Stereoselectivity of binding was demonstrated for N(6)-(R-1-phenylethyl)adenosine vs. N(6)-(S-1-phenylethyl)adenosine, as well as for the N(6)-(1-phenyl-2-pentyl)adenosine, at the rat, but not human A(3)AR. Interestingly, DPMA, a potent agonist for the A(2A)AR (K(i)=4nM), was demonstrated to be a moderately potent antagonist for the human A(3)AR (K(i)=106nM). N(6)-[(1S,2R)-2-Phenyl-1-cyclopropyl]adenosine 48 was 1100-fold more potent in binding to human (K(i)=0.63nM) than rat A(3)ARs. Dual acting A(1)/A(3) agonists (N(6)-3-chlorobenzyl- 29, N(6)-(S-1-phenylethyl)- 39, and 2-chloro-N(6)-(R-phenylisopropyl)adenosine 53) might be useful for cardioprotection.
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Affiliation(s)
| | | | | | | | - Kenneth A. Jacobson
- Corresponding author. Tel.: +1-301-496-9024; fax: +1-301-480-8422. (K.A. Jacobson)
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Rembold CM, Kaufman E. Heat induced HSP20 phosphorylation without increased cyclic nucleotide levels in swine carotid media. BMC Physiol 2003; 3:3. [PMID: 12716456 PMCID: PMC155685 DOI: 10.1186/1472-6793-3-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2003] [Accepted: 04/25/2003] [Indexed: 11/10/2022]
Abstract
BACKGROUND Heat pretreatment of swine carotid artery has been shown to increase ser16-heat shock protein 20 (HSP20) phosphorylation and suppress force, i.e., reduce force with only minimal reduction in ser19-myosin regulatory light chain (MRLC) phosphorylation. RESULTS We further investigated this response in intact histamine stimulated swine carotid artery rings. There was a heat threshold such that increased ser16-HSP20 phosphorylation and force suppression were observed between 43 degrees C and 46 degrees C. The increased ser16-HSP20 phosphorylation persisted up to 16 hours after 44.5 degrees C heat treatment. Pretreatment of swine carotid media at 44.5 degrees C increased ser16-HSP20 phosphorylation without increases in [cAMP] or [cGMP], suggesting an alternate mechanism, perhaps phosphatase inhibition, for the increase in ser16-HSP20 phosphorylation. Heat pretreatment at 47.5 degrees C reduced force by decreasing MRLC phosphorylation rather than by large increases in ser16-HSP20 phosphorylation. HSP20 phosphorylation at the putative PKC site did not change with any treatment. CONCLUSION These results demonstrate that multiple mechanisms can induce force suppression that is correlated with ser16-HSP20 phosphorylation: 1) nitrovasodilators via cGMP, 2) forskolin via cAMP, and 2) thermal stress in a cyclic nucleotide independent manner.
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Affiliation(s)
- Christopher M Rembold
- Cardiovascular Division, Departments of Internal Medicine and Physiology, University of Virginia Health System, Charlottesville, Virginia 22908 USA
| | - Elizabeth Kaufman
- Cardiovascular Division, Departments of Internal Medicine and Physiology, University of Virginia Health System, Charlottesville, Virginia 22908 USA
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Hornigold DC, Mistry R, Raymond PD, Blank JL, John Challiss RA. Evidence for cross-talk between M2 and M3 muscarinic acetylcholine receptors in the regulation of second messenger and extracellular signal-regulated kinase signalling pathways in Chinese hamster ovary cells. Br J Pharmacol 2003; 138:1340-50. [PMID: 12711635 PMCID: PMC1573780 DOI: 10.1038/sj.bjp.0705178] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. We have examined possible mechanisms of cross-talk between the G(q/11)-linked M(3) muscarinic acetylcholine (mACh) receptor and the G(i/o)-linked M(2) mACh receptor by stable receptor coexpression in Chinese hamster ovary (CHO) cells. A number of second messenger (cyclic AMP, Ins(1,4,5)P(3)) and mitogen-activated protein kinase (ERK and JNK) responses stimulated by the mACh receptor agonist methacholine were examined in CHO-m2m3 cells and compared to those stimulated in CHO-m2 and CHO-m3 cell-lines, expressing comparable levels of M(2) or M(3) mACh receptors. 2. Based on comparisons between cell-lines and pertussis toxin (PTx) pretreatment to eliminate receptor-G(i/o) coupling, evidence was obtained for (i) an M(2) mACh receptor-mediated contribution to the predominantly M(3) mACh receptor-mediated Ins(1,4,5)P(3) response and (ii) a facilitation of the inhibitory effect of M(2) mACh receptor on forskolin-stimulated cyclic AMP accumulation by M(3) mACh receptor coactivation at low agonist concentrations (MCh 10(-9)-10(-6) M). 3. The most profound cross-talk effects were observed with respect to ERK activation. Thus, while MCh stimulated ERK activation in both CHO-m2 and CHO-m3 cells (pEC(50) values: 5.64+/-0.09 and 5.57+/-0.16, respectively), the concentration-effect relation was approx 50-fold left-shifted in CHO-m2m3 cells (pEC(50): 7.17+/-0.07). In addition, the ERK response was greater and more sustained in CHO-m2m3 cells. In contrast, only minor differences were seen in the time-courses and concentration-dependencies of JNK activation in CHO-m3 and CHO-m2m3 cells. 4. Costimulation of endogenous P2Y(2) purinoceptors also caused an approx 10-fold left-shift in the MCh-stimulated ERK response in CHO-m2 cells, suggesting that the G(q/11)/G(i/o) interaction to affect ERK activation is not specific to muscarinic receptors. 5. PTx pretreatment of cells had unexpected effects on ERK activation by MCh in both CHO-m2m3 and CHO-m3 cells. Thus, in CHO-m3 cells PTx pretreatment caused a marked left-shift in the MCh concentration-effect curve, while in PTx-treated CHO-m2m3 cells the maximal responsiveness was decreased, but the potency of MCh was only slightly affected. 6. The data presented here strongly suggest that cross-talk between M(2) and M(3) mACh receptors occurs at the level of both second messenger and ERK regulation. Further, these data provide novel insights into the involvement of G(i/o) proteins in both positive and negative modulation of ERK responses evoked by G protein-coupled receptors.
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Affiliation(s)
- David C Hornigold
- Department of Cell Physiology and Pharmacology, Maurice Shock Medical Sciences Building, University of Leicester, University Road, Leicester LE1 9HN
| | - Rajendra Mistry
- Department of Cell Physiology and Pharmacology, Maurice Shock Medical Sciences Building, University of Leicester, University Road, Leicester LE1 9HN
| | - Pamela D Raymond
- Department of Cell Physiology and Pharmacology, Maurice Shock Medical Sciences Building, University of Leicester, University Road, Leicester LE1 9HN
| | - Jonathan L Blank
- Department of Cell Physiology and Pharmacology, Maurice Shock Medical Sciences Building, University of Leicester, University Road, Leicester LE1 9HN
| | - R A John Challiss
- Department of Cell Physiology and Pharmacology, Maurice Shock Medical Sciences Building, University of Leicester, University Road, Leicester LE1 9HN
- Author for correspondence:
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Abstract
(1) This study examined the effects of dopamine D(1)- and D(2)-like receptor activation upon basolateral K(+) (I(K)) currents and changes in membrane potential in opossum kidney (OK) cells. (2) The addition of amphotericin B (3 micro g ml(-1)) to the apical side resulted in a rapid increase in I(K), this effect being markedly inhibited by the addition of the K(+) channel blockers barium chloride (1 mM) or glibenclamide (10 micro M), but not apamin (1 micro M). The K(+) channel opener pinacidil increased the amphotericin B-induced I(K). The selective D(2)-like receptor agonist quinerolane increased, in a concentration dependent manner (EC(50)=136 nM), I(K) across the basolateral membrane, this effect being abolished by pre-treatment with pertussis toxin (PTX), S-sulpiride (selective D(2)-like receptor antagonist) and glibenclamide. The selective D(1)-like receptor agonist SKF 38393 did not change I(K). Both H-89 (PKA inhibitor) and chelerythrine (PKC inhibitor) failed to prevent the stimulatory effect of quinerolane upon I(K). (3) Quinerolane did not change basal levels of cyclic AMP and also failed to affect the forskolin-induced increase in cyclic AMP levels. (4) The stimulation of D(2)-like receptor was associated with a rapid hyperpolarizing effect, whereas D(1)-like receptor activation was accompanied by increases in cell membrane potential. The hyperpolarizing effect of quinerolane (EC(50)=129 nM) was prevented by pre-treatment with PTX, S-sulpiride and glibenclamide. (5) It is concluded that stimulation of dopamine D(2)-like, but not D(1)-like, receptors coupled to PTX-sensitive G proteins of the G(i/o) class produce membrane hyperpolarization through opening of K(ATP) channels.
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Affiliation(s)
- Pedro Gomes
- Institute of Pharmacology & Therapeutics, Faculty of Medicine, 4200 Porto, Portugal
| | - Patrício Soares-da-Silva
- Institute of Pharmacology & Therapeutics, Faculty of Medicine, 4200 Porto, Portugal
- Author for correspondence:
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