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Keely SJ, Barrett KE. Intestinal secretory mechanisms and diarrhea. Am J Physiol Gastrointest Liver Physiol 2022; 322:G405-G420. [PMID: 35170355 PMCID: PMC8917926 DOI: 10.1152/ajpgi.00316.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 01/31/2023]
Abstract
One of the primary functions of the intestinal epithelium is to transport fluid and electrolytes to and from the luminal contents. Under normal circumstances, absorptive and secretory processes are tightly regulated such that absorption predominates, thereby enabling conservation of the large volumes of water that pass through the intestine each day. However, in conditions of secretory diarrhea, this balance becomes dysregulated, so that fluid secretion, driven primarily by Cl- secretion, overwhelms absorptive capacity, leading to increased loss of water in the stool. Secretory diarrheas are common and include those induced by pathogenic bacteria and viruses, allergens, and disruptions to bile acid homeostasis, or as a side effect of many drugs. Here, we review the cellular and molecular mechanisms by which Cl- and fluid secretion in the intestine are regulated, how these mechanisms become dysregulated in conditions of secretory diarrhea, currently available and emerging therapeutic approaches, and how new strategies to exploit intestinal secretory mechanisms are successfully being used in the treatment of constipation.
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Affiliation(s)
- Stephen J Keely
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
| | - Kim E Barrett
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, California
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, California
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2
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de Pins B, Mendes T, Giralt A, Girault JA. The Non-receptor Tyrosine Kinase Pyk2 in Brain Function and Neurological and Psychiatric Diseases. Front Synaptic Neurosci 2021; 13:749001. [PMID: 34690733 PMCID: PMC8527176 DOI: 10.3389/fnsyn.2021.749001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/14/2021] [Indexed: 12/28/2022] Open
Abstract
Pyk2 is a non-receptor tyrosine kinase highly enriched in forebrain neurons. Pyk2 is closely related to focal adhesion kinase (FAK), which plays an important role in sensing cell contacts with extracellular matrix and other extracellular signals controlling adhesion and survival. Pyk2 shares some of FAK’s characteristics including recruitment of Src-family kinases after autophosphorylation, scaffolding by interacting with multiple partners, and activation of downstream signaling pathways. Pyk2, however, has the unique property to respond to increases in intracellular free Ca2+, which triggers its autophosphorylation following stimulation of various receptors including glutamate NMDA receptors. Pyk2 is dephosphorylated by the striatal-enriched phosphatase (STEP) that is highly expressed in the same neuronal populations. Pyk2 localization in neurons is dynamic, and altered following stimulation, with post-synaptic and nuclear enrichment. As a signaling protein Pyk2 is involved in multiple pathways resulting in sometimes opposing functions depending on experimental models. Thus Pyk2 has a dual role on neurites and dendritic spines. With Src family kinases Pyk2 participates in postsynaptic regulations including of NMDA receptors and is necessary for specific types of synaptic plasticity and spatial memory tasks. The diverse functions of Pyk2 are also illustrated by its role in pathology. Pyk2 is activated following epileptic seizures or ischemia-reperfusion and may contribute to the consequences of these insults whereas Pyk2 deficit may contribute to the hippocampal phenotype of Huntington’s disease. Pyk2 gene, PTK2B, is associated with the risk for late-onset Alzheimer’s disease. Studies of underlying mechanisms indicate a complex contribution with involvement in amyloid toxicity and tauopathy, combined with possible functional deficits in neurons and contribution in microglia. A role of Pyk2 has also been proposed in stress-induced depression and cocaine addiction. Pyk2 is also important for the mobility of astrocytes and glioblastoma cells. The implication of Pyk2 in various pathological conditions supports its potential interest for therapeutic interventions. This is possible through molecules inhibiting its activity or increasing it through inhibition of STEP or other means, depending on a precise evaluation of the balance between positive and negative consequences of Pyk2 actions.
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Affiliation(s)
- Benoit de Pins
- Institut du Fer à Moulin, Paris, France.,Inserm UMR-S 1270, Paris, France.,Faculté des Sciences et Ingénierie, Sorbonne Université, Paris, France
| | - Tiago Mendes
- Institut du Fer à Moulin, Paris, France.,Inserm UMR-S 1270, Paris, France.,Faculté des Sciences et Ingénierie, Sorbonne Université, Paris, France
| | - Albert Giralt
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Production and Validation Center of Advanced Therapies (Creatio), Faculty of Medicine and Health Science, University of Barcelona, Barcelona, Spain
| | - Jean-Antoine Girault
- Institut du Fer à Moulin, Paris, France.,Inserm UMR-S 1270, Paris, France.,Faculté des Sciences et Ingénierie, Sorbonne Université, Paris, France
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3
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Kim Y, Quach A, Das S, Barrett KE. Potentiation of calcium-activated chloride secretion and barrier dysfunction may underlie EGF receptor tyrosine kinase inhibitor-induced diarrhea. Physiol Rep 2021; 8:e14490. [PMID: 32652816 PMCID: PMC7354088 DOI: 10.14814/phy2.14490] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 05/23/2020] [Indexed: 12/13/2022] Open
Abstract
Epidermal growth factor receptor tyrosine kinase inhibitors (EGFr TKIs) are first‐line therapies for various cancers, and cause dose‐limiting severe diarrhea in many patients. We hypothesized that diarrhea caused by EGFr TKIs might reflect actions on epithelial transport, barrier function, or both, which we tested using cell cultures including murine and human enteroid‐derived monolayers (EDMs), analyzed using electrophysiological and other relevant methods. EGFr TKIs (such as afatinib, erlotinib, and osimertinib) reversed the acute inhibitory effect of EGF on chloride secretion induced by carbachol (CCh) across T84 human colonic epithelial cells, which correlated with the diarrhea‐inducing effect of each agent clinically. EGFr TKIs also reduced transepithelial electrical resistance (TEER), whereas co‐treatment with CCh delayed the decrease in TEER compared with that of cells co‐treated with EGF. Furthermore, afatinib and erlotinib prevented EGF‐ or CCh‐induced EGFr phosphorylation. EGFr TKIs also suppressed phosphorylation of extracellular signal‐regulated kinase (Erk)1/2 in response to EGF, whereas they had weaker effects on CCh‐induced Erk1/2 phosphorylation. In human EDMs, EGF potentiated ion transport induced by CCh, whereas afatinib reversed this effect. The ability of EGFr TKIs to reverse the effects of EGF on calcium‐dependent chloride secretion could contribute to the diarrheal side effects of these agents, and their disruption of epithelial barrier dysfunction is likely also pathophysiologically significant. CCh‐activated Erk1/2 phosphorylation was relatively insensitive to EGFr TKIs and delayed the deleterious effects of EGFr TKIs on barrier function. These findings confirm and extend those of other authors, and may be relevant to designing strategies to overcome the diarrheal side effects of EGFr TKIs.
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Affiliation(s)
- Younjoo Kim
- Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, CA, USA.,Division of Gastroenterology, Department of Internal Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea
| | - Andrew Quach
- Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Soumita Das
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Kim E Barrett
- Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, CA, USA
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4
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Tao G, Chityala PK. Epidermal growth factor receptor inhibitor-induced diarrhea: clinical incidence, toxicological mechanism, and management. Toxicol Res (Camb) 2021; 10:476-486. [PMID: 34141161 PMCID: PMC8201561 DOI: 10.1093/toxres/tfab026] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 12/18/2022] Open
Abstract
The epidermal growth factor receptor (EGFR) family is a class of receptor tyrosine kinase playing a central role in carcinogenesis and cancer progression. The members of this family, particularly EGFR and human epidermal growth factor receptor 2 (HER2), are the most extensively studied drug targets for malignancy. Today, numerous tyrosine kinase inhibitors targeting EGFR family have been developed to combat non-small-cell lung cancer and breast cancer. However, severe gastrointestinal (GI) toxicity leading to dose reduction and treatment discontinuation hampers the therapeutic outcome of EGFR inhibitors. Diarrhea is one of the most frequent GI side effects, especially when it comes to second-generation EGFR inhibitors. Enterocytes apoptosis and increased inflammation accompany with many oral EGFR inhibitors. Loperamide and budesonide are the first-line treatment to manage such adverse effects. However, current prophylaxis and management are all empirical interventions to relieve the symptom. They do not specifically target the toxicological mechanism of EGFR inhibitors. Hereby, those anti-diarrhea agents do not work well when used in cancer patients experiencing EGFR inhibitor-induced diarrhea. On the other hand, the toxicological mechanism of EGFR inhibitor-induced diarrhea is poorly understood. Thus, determining the mechanism behind such diarrhea is urgently in need for developing genuinely effective anti-diarrhea agents. This review aims to call attention to EGFR inhibitor-induced diarrhea, a highly occurring and devastating cancer drug toxicity.
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Affiliation(s)
- Gabriel Tao
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204, USA
| | - Pavan Kumar Chityala
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204, USA
- Division of Pharmacotherapy and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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5
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Barrett KE. Epithelial transport in digestive diseases: mice, monolayers, and mechanisms. Am J Physiol Cell Physiol 2020; 318:C1136-C1143. [PMID: 32293934 DOI: 10.1152/ajpcell.00015.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The transport of electrolytes and fluid by the intestinal epithelium is critical in health to maintain appropriate levels of fluidity of the intestinal contents. The transport mechanisms that underlie this physiological process are also subject to derangement in various digestive disease states, such as diarrheal illnesses. This article summarizes the 2019 Hans Ussing Lecture of the Epithelial Transport Group of the American Physiological Society and discusses some pathways by which intestinal transport is dysregulated, particularly in the setting of infection with the diarrheal pathogen, Salmonella, and in patients treated with small-molecule inhibitors of the tyrosine kinase activity of the epidermal growth factor receptor (EGFr-TKI). The burdensome diarrhea in patients infected with Salmonella may be attributable to decreased expression of the chloride-bicarbonate exchanger downregulated in adenoma (DRA) that participates in electroneutral NaCl absorption. This outcome is possibly secondary to increased epithelial proliferation and/or decreased epithelial differentiation that occurs following infection. Conversely, the diarrheal side effects of cancer treatment with EGFr-TKI may be related to the known ability of EGFr-associated signaling to reduce calcium-dependent chloride secretion. Overall, the findings described may suggest targets for therapeutic intervention in a variety of diarrheal disease states.
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Affiliation(s)
- Kim E Barrett
- Department of Medicine, University of California San Diego School of Medicine, La Jolla, California
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6
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Thompson BJ. YAP/TAZ: Drivers of Tumor Growth, Metastasis, and Resistance to Therapy. Bioessays 2020; 42:e1900162. [DOI: 10.1002/bies.201900162] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 02/11/2020] [Indexed: 01/17/2023]
Affiliation(s)
- Barry J. Thompson
- EMBL AustraliaJohn Curtin School of Medical ResearchThe Australian National University 131 Garran Rd, Acton 2602 Canberra ACT Australia
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7
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King SJ, Bunz M, Chappell A, Scharl M, Docherty M, Jung B, Lytle C, McCole DF. AMPK mediates inhibition of electrolyte transport and NKCC1 activity by reactive oxygen species. Am J Physiol Gastrointest Liver Physiol 2019; 317:G171-G181. [PMID: 31070932 PMCID: PMC6734373 DOI: 10.1152/ajpgi.00317.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Reactive oxygen species such as H2O2 are believed to play a prominent role in the injury and loss of transport function that affect the intestinal epithelium in inflammatory conditions such as inflammatory bowel diseases. Defects in intestinal epithelial ion transport regulation contribute to dysbiosis and inflammatory phenotypes. We previously showed that H2O2 inhibits Ca2+-dependent Cl- secretion across intestinal epithelial cells (IECs) via a phosphatidylinositol 3-kinase (PI3K)- and extracellular signal-regulated kinase (ERK)-dependent mechanism that occurs, at least in part, through inhibition of the basolateral Na+-K+-2Cl- cotransporter NKCC1. NKCC1 governs Cl- entry into crypt IECs and thus plays a critical role in maintaining the driving force for Cl- secretion. Electrolyte transport consumes large amounts of cellular energy, and direct pharmacological activation of the cellular energy sensor AMP-activated protein kinase (AMPK) has been shown to inhibit a number of ion transport proteins. Here, we show that H2O2 activates AMPK in human IEC lines and ex vivo human colon. Moreover, we demonstrate that the inhibitory effect of H2O2 on Ca2+-dependent Cl- secretion and NKCC1 activity is AMPK-dependent. This inhibitory effect is associated with a physical interaction between AMPK and NKCC1, as well as increased phosphorylation (Thr212,217) of NKCC1, without causing NKCC1 internalization. These data identify a key role for AMPK-NKCC1 interaction as a point of convergence for suppression of colonic epithelial ion transport by inflammatory reactive oxygen species.NEW & NOTEWORTHY H2O2 inhibition of intestinal epithelial Ca2+-dependent Cl- secretion involves recruitment of AMP-activated protein kinase (AMPK) downstream of ERK and phosphatidylinositol 3-kinase signaling pathways, physical interaction of AMPK with the Na+-K+-2Cl- cotransporter NKCC1, and AMPK-dependent suppression of NKCC1-mediated electrolyte influx without causing NKCC1 internalization. It is intriguing that, in human intestinal epithelial cell lines and human colon, H2O2 activation of AMPK increased phosphorylation of NKCC1 residues required for promoting, not inhibiting, NKCC1 activity. These data identify an elevated complexity of AMPK regulation of NKCC1 in the setting of an inflammatory stimulus.
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Affiliation(s)
- Stephanie J. King
- 1Division of Biomedical Sciences, University of California, Riverside, Riverside, California
| | - Michael Bunz
- 2Division of Gastroenterology, School of Medicine, University of California, San Diego, La Jolla, California,3Kreisklinik Woert an der Donau, Department of Anaesthesiology and Intensive Care Medicine, Woerth an der Donau, Germany
| | - Alfred Chappell
- 2Division of Gastroenterology, School of Medicine, University of California, San Diego, La Jolla, California
| | - Michael Scharl
- 2Division of Gastroenterology, School of Medicine, University of California, San Diego, La Jolla, California,4Division of Gastroenterology and Hepatology, Zurich Center for Integrative Human Physiology, University Hospital and University of Zurich, Zurich, Switzerland
| | - Michael Docherty
- 2Division of Gastroenterology, School of Medicine, University of California, San Diego, La Jolla, California
| | - Barbara Jung
- 2Division of Gastroenterology, School of Medicine, University of California, San Diego, La Jolla, California
| | - Christian Lytle
- 1Division of Biomedical Sciences, University of California, Riverside, Riverside, California
| | - Declan F. McCole
- 1Division of Biomedical Sciences, University of California, Riverside, Riverside, California
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8
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Cao Z, Singh B, Li C, Markham NO, Carrington LJ, Franklin JL, Graves‐Deal R, Kennedy EJ, Goldenring JR, Coffey RJ. Protein kinase A-mediated phosphorylation of naked cuticle homolog 2 stimulates cell-surface delivery of transforming growth factor-α for epidermal growth factor receptor transactivation. Traffic 2019; 20:357-368. [PMID: 30941853 PMCID: PMC6618044 DOI: 10.1111/tra.12642] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/22/2019] [Accepted: 03/25/2019] [Indexed: 12/20/2022]
Abstract
The classic mode of G protein-coupled receptor (GPCR)-mediated transactivation of the receptor tyrosine kinase epidermal growth factor receptor (EGFR) transactivation occurs via matrix metalloprotease (MMP)-mediated cleavage of plasma membrane-anchored EGFR ligands. Herein, we show that the Gαs-activating GPCR ligands vasoactive intestinal peptide (VIP) and prostaglandin E2 (PGE2 ) transactivate EGFR through increased cell-surface delivery of the EGFR ligand transforming growth factor-α (TGFα) in polarizing madin-darby canine kidney (MDCK) and Caco-2 cells. This is achieved by PKA-mediated phosphorylation of naked cuticle homolog 2 (NKD2), previously shown to bind TGFα and direct delivery of TGFα-containing vesicles to the basolateral surface of polarized epithelial cells. VIP and PGE2 rapidly activate protein kinase A (PKA) that then phosphorylates NKD2 at Ser-223, a process that is facilitated by the molecular scaffold A-kinase anchoring protein 12 (AKAP12). This phosphorylation stabilized NKD2, ensuring efficient cell-surface delivery of TGFα and increased EGFR activation. Thus, GPCR-triggered, PKA/AKAP12/NKD2-regulated targeting of TGFα to the cell surface represents a new mode of EGFR transactivation that occurs proximal to ligand cleavage by MMPs.
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Affiliation(s)
- Zheng Cao
- Department of MedicineVanderbilt University Medical CenterNashvilleTennessee
- Epithelial Biology CenterVanderbilt University School of MedicineNashvilleTennessee
| | - Bhuminder Singh
- Department of MedicineVanderbilt University Medical CenterNashvilleTennessee
- Epithelial Biology CenterVanderbilt University School of MedicineNashvilleTennessee
- Department of Cell and Developmental BiologyVanderbilt UniversityNashvilleTennessee
| | - Cunxi Li
- Jiaen Genetics LaboratoryBeijing Jiaen HospitalBeijingChina
- Genetics CenterShenzhen IVF Gynecology HospitalShenzhenChina
| | - Nicholas O. Markham
- Department of MedicineVanderbilt University Medical CenterNashvilleTennessee
- Epithelial Biology CenterVanderbilt University School of MedicineNashvilleTennessee
| | | | - Jeffrey L. Franklin
- Department of MedicineVanderbilt University Medical CenterNashvilleTennessee
- Epithelial Biology CenterVanderbilt University School of MedicineNashvilleTennessee
- Department of Cell and Developmental BiologyVanderbilt UniversityNashvilleTennessee
- Department of MedicineVeterans Affairs Medical CenterNashvilleTennessee
| | - Ramona Graves‐Deal
- Department of MedicineVanderbilt University Medical CenterNashvilleTennessee
- Epithelial Biology CenterVanderbilt University School of MedicineNashvilleTennessee
| | - Eileen J. Kennedy
- Department of Pharmaceutical and Biomedical Sciences, College of PharmacyUniversity of GeorgiaAthensGeorgia
| | - James R. Goldenring
- Epithelial Biology CenterVanderbilt University School of MedicineNashvilleTennessee
- Department of Cell and Developmental BiologyVanderbilt UniversityNashvilleTennessee
- Department of MedicineVeterans Affairs Medical CenterNashvilleTennessee
- Department of SurgeryVanderbilt University School of MedicineNashvilleTennessee
| | - Robert J. Coffey
- Department of MedicineVanderbilt University Medical CenterNashvilleTennessee
- Epithelial Biology CenterVanderbilt University School of MedicineNashvilleTennessee
- Department of Cell and Developmental BiologyVanderbilt UniversityNashvilleTennessee
- Department of MedicineVeterans Affairs Medical CenterNashvilleTennessee
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9
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Dodmane PR, Schulte NA, Heires AJ, Band H, Romberger DJ, Toews ML. Biphasic changes in airway epithelial cell EGF receptor binding and phosphorylation induced by components of hogbarn dust. Exp Lung Res 2019; 44:443-454. [PMID: 30862200 DOI: 10.1080/01902148.2019.1575931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE OF THE STUDY Workers in enclosed hogbarns experience an increased incidence of airway inflammation and obstructive lung disease, and an aqueous hogbarn dust extract (HDE) induces multiple inflammation-related responses in cultured airway epithelial cells. Epidermal growth factor receptor (EGFR) phosphorylation and activation has been identified as one important mediator of inflammatory cytokine release from these cells. The studies here investigated both early and late phase adaptive changes in EGFR binding properties and subcellular localization induced by exposure of cells to HDE. MATERIALS AND METHODS Cell surface EGFRs were quantified as binding to intact cells on ice. EGFR phosphorylation, expression, and localization were assessed with anti-EGFR antibodies and either blotting or confocal microscopy. RESULTS In BEAS-2B and primary human bronchial epithelial cells, HDE induced decreases in cell surface EGFR binding following both 15-min and 18-h exposures. In contrast, H292 cells exhibited only the 15-min decrease, with binding near the control level at 18 hr. Confocal microscopy showed that the 15-min decrease in binding is due to EGFR endocytosis. Although total EGFR immunoreactivity decreased markedly at 18 hr in confocal microscopy with BEAS-2B cells, immunoblots showed no loss of EGFR protein. HDE stimulated EGFR phosphorylation at both 15 min and 18 hr in BEAS-2B cells and primary cells, but only at 15 min in H292 cells, indicating that the different EGFR binding changes among these cell types is likely related to their different time-dependent changes in phosphorylation. CONCLUSIONS These studies extend the evidence for EGFRs as important cellular targets for components of HDE and they reveal novel patterns of EGFR phosphorylation and binding changes that vary among airway epithelial cell types. The results provide both impetus and convenient assays for identifying the EGFR-activating components and pathways that likely contribute to hogbarn dust-induced lung disease in agricultural workers.
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Affiliation(s)
- Puttappa R Dodmane
- a Department of Pharmacology and Experimental Neuroscience , University of Nebraska Medical Center , Omaha , NE , USA
| | - Nancy A Schulte
- a Department of Pharmacology and Experimental Neuroscience , University of Nebraska Medical Center , Omaha , NE , USA
| | - Art J Heires
- b Veterans Affairs Nebraska-Western Iowa Health Care System , Research Service , Omaha , NE , USA.,c Pulmonary, Critical Care, Sleep & Allergy Division, Department of Internal Medicine , University of Nebraska Medical Center , Omaha , NE , USA
| | - Hamid Band
- d Eppley Institute for Research in Cancer and Allied Diseases , University of Nebraska Medical Center , Omaha , NE , USA
| | - Debra J Romberger
- b Veterans Affairs Nebraska-Western Iowa Health Care System , Research Service , Omaha , NE , USA.,c Pulmonary, Critical Care, Sleep & Allergy Division, Department of Internal Medicine , University of Nebraska Medical Center , Omaha , NE , USA
| | - Myron L Toews
- a Department of Pharmacology and Experimental Neuroscience , University of Nebraska Medical Center , Omaha , NE , USA
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10
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Pelissier-Rota M, Chartier NT, Bonaz B, Jacquier-Sarlin MR. A crosstalk between muscarinic and CRF2 receptors regulates cellular adhesion properties of human colon cancer cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1246-1259. [PMID: 28432022 DOI: 10.1016/j.bbamcr.2017.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 04/04/2017] [Accepted: 04/14/2017] [Indexed: 12/24/2022]
Abstract
Patients with inflammatory bowel disease often suffer from chronic and relapsing intestinal inflammation that favor the development of colitis associated cancer. An alteration of the epithelial intestinal barrier function observed in IBD is supposed to be a consequence of stress. It has been proposed that corticotrophin-releasing factor receptor (CRF2), one of the two receptors of CRF, the principal neuromediator of stress, acts on cholinergic nerves to induce stress-mediated epithelial barrier dysfunction. Non-neuronal acetylcholine (Ach) and muscarinic receptors (mAchR) also contribute to alterations of epithelial cell functions. In this study, we investigated the mechanisms through which stress and Ach modulate epithelial cell adhesive properties. We show that Ach-induced activation of mAchR in HT-29 cells results in cell dissociation together with changes in cell-matrix contacts, which correlates with the acquisition of invasive potential consistent with a matrix metalloproteinase (MMP) mode of invasion. These processes result from mAchR subsequent stimulation of the cascade of src/Erk and FAK activation. Ach-induced secretion of laminin 332 leads to α3β1 integrin activation and RhoA-dependent reorganization of the actin cytoskeleton. We show that Ach-mediated effects on cell adhesion are blocked by astressin 2b, a CRF2 antagonist, suggesting that Ach action depends partly on CRF2 signaling. This is reinforced by the fact that Ach-mediated activation of mAchR stimulates both the synthesis and the release of CRF2 ligands in HT-29 cells (effects blocked by atropine). In summary, our data provides evidence for a novel intracellular circuit involving mAchR acting on CRF2-signaling that could mediate colonic mucosal barrier dysfunction and exacerbate mucosal inflammation.
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Affiliation(s)
- M Pelissier-Rota
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France; INSERM U1216, F-38000 Grenoble, France
| | - N T Chartier
- Biotechnology Center, Technical University Dresden, 01307 Dresden, Germany
| | - B Bonaz
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France; INSERM U1216, F-38000 Grenoble, France; CHU, Grenoble, F-38000 Grenoble, France
| | - M R Jacquier-Sarlin
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France; INSERM U1216, F-38000 Grenoble, France.
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11
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Anguita E, Villalobo A. Src-family tyrosine kinases and the Ca 2+ signal. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:915-932. [PMID: 27818271 DOI: 10.1016/j.bbamcr.2016.10.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/25/2016] [Accepted: 10/30/2016] [Indexed: 01/08/2023]
Abstract
In this review, we shall describe the rich crosstalk between non-receptor Src-family kinases (SFKs) and the Ca2+ transient generated in activated cells by a variety of extracellular and intracellular stimuli, resulting in diverse signaling events. The exchange of information between SFKs and Ca2+ is reciprocal, as it flows in both directions. These kinases are main actors in pathways leading to the generation of the Ca2+ signal, and reciprocally, the Ca2+ signal modulates SFKs activity and functions. We will cover how SFKs participate in the generation of the cytosolic Ca2+ rise upon activation of a series of receptors and the mechanism of clearance of this Ca2+ signal. The role of SFKs modulating Ca2+-translocating channels participating in these events will be amply discussed. Finally, the role of the Ca2+ sensor protein calmodulin on the activity of c-Src, and potentially on other SFKs, will be outlined as well. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Estefanía Anguita
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/ Arturo Duperier 4, E-28029 Madrid, Spain
| | - Antonio Villalobo
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/ Arturo Duperier 4, E-28029 Madrid, Spain.
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12
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Di Liberto V, Borroto-Escuela DO, Frinchi M, Verdi V, Fuxe K, Belluardo N, Mudò G. Existence of muscarinic acetylcholine receptor (mAChR) and fibroblast growth factor receptor (FGFR) heteroreceptor complexes and their enhancement of neurite outgrowth in neural hippocampal cultures. Biochim Biophys Acta Gen Subj 2016; 1861:235-245. [PMID: 27815219 DOI: 10.1016/j.bbagen.2016.10.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 10/15/2016] [Accepted: 10/31/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Recently, it was demonstrated that G-protein-coupled receptors (GPCRs) can transactivate tyrosine kinase receptors in absence of their ligands. In this work, driven by the observation that mAChRs and fibroblast growth factor receptors (FGFRs) share signalling pathways and regulation of brain functions, it was decided to explore whether mAChRs activation may transactivate FGFRs and, if so, to characterize the related trophic effects in cultured hippocampal neurons. METHODS Oxotremorine-M transactivation of FGFRs and related trophic effects were tested in primary hippocampal neurons. Western blotting and in situ proximity ligation assay (PLA) were used to detect FGFR phosphorylation (pFGFR) levels and M1R-FGFR1 heteroreceptor complexes, respectively. RESULTS Oxotremorine-M, a non-selective mAChRs agonist, was able to transactivate FGFR and this transactivation was blocked by Src inhibitors. Oxotremorine-M treatment produced a significant increase in the primary neurite outgrowth that was blocked by pre-treatment with the pFGFR inhibitor SU5402 and Src inhibitors. This trophic effect was almost similar to that induced by fibroblast growth factor-2 (FGF-2). By using atropine as nonselective mAChRs or pirenzepine as selective antagonist for M1 receptor (M1R) we could show that mAChRs are involved in modulating the pFGFRs. Using PLA, M1R-FGFR1 heteroreceptor complexes were identified in the hippocampus and cerebral cortex. CONCLUSION The current findings, by showing functional mAChR-FGFR interactions, will contribute to advance the understanding of the mechanisms involved in the actions of cholinergic drugs on neuronal plasticity. GENERAL SIGNIFICANT Data may help to develop novel therapeutic strategies not only for neurodegenerative diseases but also for depression-induced atrophy of hippocampal neurons.
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Affiliation(s)
- V Di Liberto
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Corso Tukory 129, 90134 Palermo, Italy.
| | - D O Borroto-Escuela
- Karolinska Instituet, Department of Neuroscience, Retzius väg 8, 17177 Stockholm, Sweden; Department of Biomolecular Science, Section of Physiology, University of Urbino, Campus Scientifico Enrico Mattei, via Ca' le Suore 2, I-61029 Urbino, Italy; Observatorio Cubano de Neurociencias, Grupo Bohío-Estudio, Zayas 50, 62100 Yaguajay, Cuba.
| | - M Frinchi
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Corso Tukory 129, 90134 Palermo, Italy.
| | - V Verdi
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Corso Tukory 129, 90134 Palermo, Italy.
| | - K Fuxe
- Karolinska Instituet, Department of Neuroscience, Retzius väg 8, 17177 Stockholm, Sweden.
| | - N Belluardo
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Corso Tukory 129, 90134 Palermo, Italy.
| | - G Mudò
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Corso Tukory 129, 90134 Palermo, Italy.
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Chien PTY, Lin CC, Hsiao LD, Yang CM. c-Src/Pyk2/EGFR/PI3K/Akt/CREB-activated pathway contributes to human cardiomyocyte hypertrophy: Role of COX-2 induction. Mol Cell Endocrinol 2015; 409:59-72. [PMID: 25869400 DOI: 10.1016/j.mce.2015.04.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 03/23/2015] [Accepted: 04/07/2015] [Indexed: 12/27/2022]
Abstract
Thrombin and COX-2 regulating cardiac hypertrophy are via various signaling cascades. Several transcriptional factors including CREB involve in COX-2 expression. However, the interplay among thrombin, CREB, and COX-2 in primary human neonatal ventricular cardiomyocytes remains unclear. In this study, thrombin-induced COX-2 promoter activity, mRNA and protein expression, and PGE2 synthesis were attenuated by pretreatment with the inhibitors of c-Src (PP1), Pyk2 (PF431396), EGFR (AG1478), PI3K/Akt (LY294002/SH-5), and p300 (GR343), or transfection with siRNAs of c-Src, Pyk2, EGFR, p110, Akt, CREB, and p300. Moreover, thrombin-stimulated phosphorylation of c-Src, Pyk2, EGFR, Akt, CREB and p300 was attenuated by their respective inhibitors. These results indicate that thrombin-induced COX-2 expression is mediated through PAR-1/c-Src/Pyk2/EGFR/PI3K/Akt linking to CREB and p300 cascades. Functionally, thrombin-induced hypertrophy and ANF/BNP release were, at least in part, mediated through a PAR-1/COX-2-dependent pathway. We uncover the importance of COX-2 regarding human cardiomyocyte hypertrophy that will provide a therapeutic intervention in cardiovascular diseases.
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Affiliation(s)
- Peter Tzu-Yu Chien
- Graduate Institute of Biomedical Sciences, Health Ageing Research Center, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan; Department of Physiology and Pharmacology, Health Ageing Research Center, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan
| | - Chih-Chung Lin
- Department of Anesthetics, Chang Gung Memorial Hospital at Lin-Kou and College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan
| | - Li-Der Hsiao
- Department of Anesthetics, Chang Gung Memorial Hospital at Lin-Kou and College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan
| | - Chuen-Mao Yang
- Graduate Institute of Biomedical Sciences, Health Ageing Research Center, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan; Department of Physiology and Pharmacology, Health Ageing Research Center, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan.
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Cholinergic transactivation of the EGFR in HaCaT keratinocytes stimulates a flotillin-1 dependent MAPK-mediated transcriptional response. Int J Mol Sci 2015; 16:6447-63. [PMID: 25803106 PMCID: PMC4394542 DOI: 10.3390/ijms16036447] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 03/06/2015] [Accepted: 03/17/2015] [Indexed: 12/13/2022] Open
Abstract
Acetylcholine and its receptors regulate numerous cellular processes in keratinocytes and other non-neuronal cells. Muscarinic acetylcholine receptors are capable of transactivating the epidermal growth factor receptor (EGFR) and, downstream thereof, the mitogen-activated protein kinase (MAPK) cascade, which in turn regulates transcription of genes involved in cell proliferation and migration. We here show that cholinergic stimulation of human HaCaT keratinocytes results in increased transcription of matrix metalloproteinase MMP-3 as well as several ligands of the epidermal growth factor family. Since both metalloproteinases and the said ligands are involved in the transactivation of the EGFR, this transcriptional upregulation may provide a positive feed-forward loop for EGFR/MAPK activation. We here also show that the cholinergic EGFR and MAPK activation and the upregulation of MMP-3 and EGF-like ligands are dependent on the expression of flotillin-1 which we have previously shown to be a regulator of MAPK signaling.
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15
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Microbial sensing by goblet cells controls immune surveillance of luminal antigens in the colon. Mucosal Immunol 2015; 8:198-210. [PMID: 25005358 PMCID: PMC4268115 DOI: 10.1038/mi.2014.58] [Citation(s) in RCA: 184] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 06/03/2014] [Indexed: 02/07/2023]
Abstract
The delivery of luminal substances across the intestinal epithelium to the immune system is a critical event in immune surveillance, resulting in tolerance to dietary antigens and immunity to pathogens. How this process is regulated is largely unknown. Recently goblet cell-associated antigen passages (GAPs) were identified as a pathway delivering luminal antigens to underlying lamina propria (LP) dendritic cells in the steady state. Here, we demonstrate that goblet cells (GCs) form GAPs in response to acetylcholine (ACh) acting on muscarinic ACh receptor 4. GAP formation in the small intestine was regulated at the level of ACh production, as GCs rapidly formed GAPs in response to ACh analogs. In contrast, colonic GAP formation was regulated at the level of GC responsiveness to ACh. Myd88-dependent microbial sensing by colonic GCs inhibited the ability of colonic GCs to respond to Ach to form GAPs and deliver luminal antigens to colonic LP-antigen-presenting cells (APCs). Disruption of GC microbial sensing in the setting of an intact gut microbiota opened colonic GAPs, and resulted in recruitment of neutrophils and APCs and production of inflammatory cytokines. Thus GC intrinsic sensing of the microbiota has a critical role regulating the exposure of the colonic immune system to luminal substances.
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Ockenga W, Kühne S, Bocksberger S, Banning A, Tikkanen R. Epidermal growth factor receptor transactivation is required for mitogen-activated protein kinase activation by muscarinic acetylcholine receptors in HaCaT keratinocytes. Int J Mol Sci 2014; 15:21433-54. [PMID: 25421240 PMCID: PMC4264234 DOI: 10.3390/ijms151121433] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 11/13/2014] [Accepted: 11/17/2014] [Indexed: 01/03/2023] Open
Abstract
Non-neuronal acetylcholine plays a substantial role in the human skin by influencing adhesion, migration, proliferation and differentiation of keratinocytes. These processes are regulated by the Mitogen-Activated Protein (MAP) kinase cascade. Here we show that in HaCaT keratinocytes all five muscarinic receptor subtypes are expressed, but M1 and M3 are the subtypes involved in mitogenic signaling. Stimulation with the cholinergic agonist carbachol leads to activation of the MAP kinase extracellular signal regulated kinase, together with the protein kinase Akt. The activation is fully dependent on the transactivation of the epidermal growth factor receptor (EGFR), which even appears to be the sole pathway for the muscarinic receptors to facilitate MAP kinase activation in HaCaT cells. The transactivation pathway involves a triple-membrane-passing process, based on activation of matrix metalloproteases, and extracellular ligand release; whereas phosphatidylinositol 3-kinase, Src family kinases or protein kinase C do not appear to be involved in MAP kinase activation. Furthermore, phosphorylation, ubiquitination and endocytosis of the EGF receptor after cholinergic transactivation are different from that induced by a direct stimulation with EGF, suggesting that ligands other than EGF itself mediate the cholinergic transactivation.
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Affiliation(s)
- Wymke Ockenga
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany.
| | - Sina Kühne
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany.
| | - Simone Bocksberger
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany.
| | - Antje Banning
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany.
| | - Ritva Tikkanen
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany.
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Aydın B, Kan B, Cabadak H. The role of intracellular pathways in the proliferation of human K562 cells mediated by muscarinic receptors. Leuk Res 2013; 37:1144-9. [PMID: 23800797 DOI: 10.1016/j.leukres.2013.05.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 05/04/2013] [Accepted: 05/26/2013] [Indexed: 10/26/2022]
Abstract
Muscarinic acetylcholine receptors (mAChRs) are members of the superfamily of G protein coupled receptors (GPCRs). Muscarinic receptors are relatively abundant in the central nervous system and in the peripheral parasympathetic nervous system. Several studies have suggested that muscarinic receptors also mediate some cellular events in hematopoietic cells. K562 erythroleukemia cells contain muscarinic receptors M2, M3 and M4, and activation of muscarinic receptors changes cell proliferation. We examined the effects of several compounds on cell proliferation in K562 erythroleukemia cells. These included a muscarinic receptor agonist carbachol (CCh), a protein kinase inhibitor staurosporine; the phospholipase C inhibitor U73122, the MEK 1-2 inhibitor UO126, the PI3-kinase inhibitor wortmannin, the Ca(2+) chelators BAPTA/AM and 2-aminoethoxy-diphenylborate (2APB). In addition, we also investigated muscarinic receptor mediated protein kinase C (PKC) expression in K562 cells. CCh caused a decrease in DNA synthesis in K562 cells supplemented with 1% fetal bovine serum after starvation. Pre-treatment of K562 cells with U73122 and BAPTA/AM antagonized the inhibitory effect of CCh, suggesting that phospholipase C and intracellular calcium are involved in CCh-mediated inhibition of proliferation in K562 cells. Our data also suggest that the regulatory roles of protein kinase C and the MAPK/ERK pathways in K562 cell proliferation are independent of cholinergic activation.
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Affiliation(s)
- Banu Aydın
- Department of Biophysics, Marmara University School of Medicine, Istanbul, Turkey
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18
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Cho-Clark M, Larco DO, Semsarzadeh NN, Vasta F, Mani SK, Wu TJ. GnRH-(1-5) transactivates EGFR in Ishikawa human endometrial cells via an orphan G protein-coupled receptor. Mol Endocrinol 2013; 28:80-98. [PMID: 24264576 DOI: 10.1210/me.2013-1203] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The decapeptide GnRH is known for its central role in the regulation of the hypothalamo-pituitary-gonadal axis. In addition, it is also known to have local effects within peripheral tissues. The zinc metalloendopeptidase, EC 3.4.24.15 (EP24.15), can cleave GnRH at the Tyr(5)-Gly(6) bond to form the pentapeptide, GnRH-(1-5). The central and peripheral effect of GnRH-(1-5) is different from its parent peptide, GnRH. In the current study, we examined the effect of GnRH-(1-5) on epidermal growth factor receptor (EGFR) phosphorylation and cellular migration. Using the Ishikawa cell line as a model of endometrial cancer, we demonstrate that GnRH-(1-5) stimulates epidermal growth factor release, increases the phosphorylation of EGFR (P < .05) at three tyrosine sites (992, 1045, 1068), and promotes cellular migration. In addition, we also demonstrate that these actions of GnRH-(1-5) are mediated by the orphan G protein-coupled receptor 101 (GPR101). Down-regulation of GPR101 expression blocked the GnRH-(1-5)-mediated release of epidermal growth factor and the subsequent phosphorylation of EGFR and cellular migration. These results suggest that GPR101 is a critical requirement for GnRH-(1-5) transactivation of EGFR in Ishikawa cells.
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Affiliation(s)
- Madelaine Cho-Clark
- Department of Obstetrics and Gynecology (T.J.W., M.C., F.V.) and the Program in Molecular and Cellular Biology (D.O.L., T.J.W.), Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814; and Departments of Molecular and Cellular Biology and Neuroscience (S.K.M.), Baylor College of Medicine, Houston, Texas 77030
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The EGF receptor and HER2 participate in TNF-α-dependent MAPK activation and IL-8 secretion in intestinal epithelial cells. Mediators Inflamm 2012; 2012:207398. [PMID: 22988345 PMCID: PMC3440955 DOI: 10.1155/2012/207398] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Accepted: 07/24/2012] [Indexed: 12/29/2022] Open
Abstract
TNF-α activates multiple mitogen-activated protein kinase (MAPK) cascades in intestinal epithelial cells (IECs) leading to the secretion of interleukin 8 (IL-8), a neutrophil chemoattractant and an angiogenic factor with tumor promoting properties. As the epidermal growth factor receptor (EGFR) is a known transducer of proliferative signals and a potent activator of MAPKs, we hypothesized that the EGFR participates in TNF-dependent MAPK activation and IL-8 secretion by intestinal epithelial cells (IECs).
We show that the EGFR is tyrosine-phosphorylated following treatment of IECs (HT-29 and IEC-6) with TNF-α. This requires EGFR autophosphorylation as it was blocked by the EGFR kinase inhibitor AG1478. Autophosphorylation was also inhibited by both a Src-kinase inhibitor and the metalloproteinase inhibitor batimastat. TNF treatment of IECs resulted in the accumulation of soluble TGF-α; treatment of IECs with batimastat suppressed TGF-α release and immunoneutralization of TGF-α resulted in decreased EGFR and ERK phosphorylations. TNF-α treatment of IECs resulted in an association between EGFR and HER2 and inhibition of HER2 using a specific inhibitor AG879 in combination with AG1478-suppressed TNF-α-dependent ERK phosphorylation and IL-8 release. Downregulation of HER2 via siRNA resulted in a significant decrease in ERK phosphorylation and a 50% reduction in IL-8 secretion.
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Kajiya M, Ichimonji I, Min C, Zhu T, Jin JO, Yu Q, Almazrooa SA, Cha S, Kawai T. Muscarinic type 3 receptor induces cytoprotective signaling in salivary gland cells through epidermal growth factor receptor transactivation. Mol Pharmacol 2012; 82:115-24. [PMID: 22511543 DOI: 10.1124/mol.111.077354] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Muscarinic type 3 receptor (M3R) plays a pivotal role in the induction of glandular fluid secretions. Although M3R is often the target of autoantibodies in Sjögren's syndrome (SjS), chemical agonists for M3R are clinically used to stimulate saliva secretion in patients with SjS. Aside from its activity in promoting glandular fluid secretion, however, it is unclear whether activation of M3R is related to other biological events in SjS. This study aimed to investigate the cytoprotective effect of chemical agonist-mediated M3R activation on apoptosis induced in human salivary gland (HSG) cells. Carbachol (CCh), a muscarinic receptor-specific agonist, abrogated tumor necrosis factor α/interferon γ-induced apoptosis through pathways involving caspase 3/7, but its cytoprotective effect was decreased by a M3R antagonist, a mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (ERK) inhibitor, a phosphatidylinositol 3-kinase/Akt inhibitor, or an epidermal growth factor receptor (EGFR) inhibitor. Ligation of M3R with CCh transactivated EGFR and phosphorylated ERK and Akt, the downstream targets of EGFR. Inhibition of intracellular calcium release or protein kinase C δ, both of which are involved in the cell signaling of M3R-mediated fluid secretion, did not affect CCh-induced ERK or Akt phosphorylation. CCh stimulated Src phosphorylation and binding to EGFR. A Src inhibitor attenuated the CCh/M3R-induced cytoprotective effect and EGFR transactivation cascades. Overall, these results indicated that CCh/M3R induced transactivation of EGFR through Src activation leading to ERK and Akt phosphorylation, which in turn suppressed caspase 3/7-mediated apoptotic signals in HSG cells. This study, for the first time, proposes that CCh-mediated M3R activation can promote not only fluid secretion but also survival of salivary gland cells in the inflammatory context of SjS.
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Affiliation(s)
- Mikihito Kajiya
- Department of Immunology, Forsyth Institute, Cambridge, Massachusetts 02142, USA
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21
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Engagement of β-arrestin by transactivated insulin-like growth factor receptor is needed for V2 vasopressin receptor-stimulated ERK1/2 activation. Proc Natl Acad Sci U S A 2012; 109:E1028-37. [PMID: 22493236 DOI: 10.1073/pnas.1112422109] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
G protein-coupled receptors (GPCRs) have been shown to activate the mitogen-activated protein kinases, ERK1/2, through both G protein-dependent and -independent mechanisms. Here, we describe a G protein-independent mechanism that unravels an unanticipated role for β-arrestins. Stimulation of the V2 vasopressin receptor (V2R) in cultured cells or in vivo in rat kidney medullar collecting ducts led to the activation of ERK1/2 through the metalloproteinase-mediated shedding of a factor activating the insulin-like growth factor receptor (IGFR). This process was found to be both Src- and β-arrestin-dependent. Whereas Src was found to act upstream of the metalloproteinase activation and be required for the release of the IGFR-activating factor, β-arrestins were found to act downstream of the IGFR transactivation. Unexpectedly, the engagement of β-arrestins by the IGFR but not by the V2R was needed to promote the vasopressin-stimulated ERK1/2 activation, indicating that a pool of β-arrestins distinct from those β-arrestins recruited to the V2R acts downstream of the receptor tyrosine kinase to activate ERK1/2. Such a dual site of action for β-arrestins helps explain the pleiotropic actions of this scaffolding protein. Given the role that V2R-stimulated ERK1/2 plays in kidney cell proliferation, this transactivation mechanism may have important implications for renal pathophysiology. Still, the role of β-arrestins downstream of a transactivation event is not limited to the V2R, because we observed a similar involvement for an unrelated GPCR (the platelet-activating factor receptor), indicating that it may be a general mechanism shared among GPCRs.
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Lanzafame AA, Christopoulos A, Mitchelson F. Cellular Signaling Mechanisms for Muscarinic Acetylcholine Receptors. ACTA ACUST UNITED AC 2011. [DOI: 10.3109/10606820308263] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Paul G, Marchelletta RR, McCole DF, Barrett KE. Interferon-γ alters downstream signaling originating from epidermal growth factor receptor in intestinal epithelial cells: functional consequences for ion transport. J Biol Chem 2011; 287:2144-55. [PMID: 22069319 DOI: 10.1074/jbc.m111.318139] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The epidermal growth factor receptor (EGFr) regulates many cellular functions, such as proliferation, apoptosis, and ion transport. Our aim was to investigate whether long term treatment with interferon-γ (IFN-γ) modulates EGF activation of downstream signaling pathways in intestinal epithelial cells and if this contributes to dysregulation of epithelial ion transport in inflammation. Polarized monolayers of T(84) and HT29/cl.19A colonocytes were preincubated with IFN-γ prior to stimulation with EGF. Basolateral potassium transport was studied in Ussing chambers. We also studied inflamed colonic mucosae from C57BL/6 mice treated with dextran sulfate sodium or mdr1a knock-out mice and controls. IFN-γ increased intestinal epithelial EGFr expression without increasing its phosphorylation. Conversely, IFN-γ caused a significant decrease in EGF-stimulated phosphorylation of specific EGFr tyrosine residues and activation of ERK but not Akt-1. In IFNγ-pretreated cells, the inhibitory effect of EGF on carbachol-stimulated K(+) channel activity was lost. In inflamed colonic tissues, EGFr expression was significantly increased, whereas ERK phosphorylation was reduced. Thus, although it up-regulates EGFr expression, IFN-γ causes defective EGFr activation in colonic epithelial cells via reduced phosphorylation of specific EGFr tyrosine residues. This probably accounts for altered downstream signaling consequences. These observations were corroborated in the setting of colitis. IFN-γ also abrogates the ability of EGF to inhibit carbachol-stimulated basolateral K(+) currents. Our data suggest that, in the setting of inflammation, the biological effect of EGF, including the inhibitory effect of EGF on Ca(2+)-dependent ion transport, is altered, perhaps contributing to diarrheal and other symptoms in vivo.
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Affiliation(s)
- Gisela Paul
- Division of Gastroenterology, University of California, San Diego, School of Medicine, La Jolla, California 92093, USA
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24
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Müller KM, Tveteraas IH, Aasrum M, Ødegård J, Dawood M, Dajani O, Christoffersen T, Sandnes DL. Role of protein kinase C and epidermal growth factor receptor signalling in growth stimulation by neurotensin in colon carcinoma cells. BMC Cancer 2011; 11:421. [PMID: 21961726 PMCID: PMC3196723 DOI: 10.1186/1471-2407-11-421] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 10/02/2011] [Indexed: 12/19/2022] Open
Abstract
Background Neurotensin has been found to promote colon carcinogenesis in rats and mice, and proliferation of human colon carcinoma cell lines, but the mechanisms involved are not clear. We have examined signalling pathways activated by neurotensin in colorectal and pancreatic carcinoma cells. Methods Colon carcinoma cell lines HCT116 and HT29 and pancreatic adenocarcinoma cell line Panc-1 were cultured and stimulated with neurotensin or epidermal growth factor (EGF). DNA synthesis was determined by incorporation of radiolabelled thymidine into DNA. Levels and phosphorylation of proteins in signalling pathways were assessed by Western blotting. Results Neurotensin stimulated the phosphorylation of both extracellular signal-regulated kinase (ERK) and Akt in all three cell lines, but apparently did so through different pathways. In Panc-1 cells, neurotensin-induced phosphorylation of ERK, but not Akt, was dependent on protein kinase C (PKC), whereas an inhibitor of the β-isoform of phosphoinositide 3-kinase (PI3K), TGX221, abolished neurotensin-induced Akt phosphorylation in these cells, and there was no evidence of EGF receptor (EGFR) transactivation. In HT29 cells, in contrast, the EGFR tyrosine kinase inhibitor gefitinib blocked neurotensin-stimulated phosphorylation of both ERK and Akt, indicating transactivation of EGFR, independently of PKC. In HCT116 cells, neurotensin induced both a PKC-dependent phosphorylation of ERK and a metalloproteinase-mediated transactivation of EGFR that was associated with a gefitinib-sensitive phosphorylation of the downstream adaptor protein Shc. The activation of Akt was also inhibited by gefitinib, but only partly, suggesting a mechanism in addition to EGFR transactivation. Inhibition of PKC blocked neurotensin-induced DNA synthesis in HCT116 cells. Conclusions While acting predominantly through PKC in Panc-1 cells and via EGFR transactivation in HT29 cells, neurotensin used both these pathways in HCT116 cells. In these cells, neurotensin-induced activation of ERK and stimulation of DNA synthesis was PKC-dependent, whereas activation of the PI3K/Akt pathway was mediated by stimulation of metalloproteinases and subsequent transactivation of the EGFR. Thus, the data show that the signalling mechanisms mediating the effects of neurotensin involve multiple pathways and are cell-dependent.
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Affiliation(s)
- Kristin M Müller
- Department of Pharmacology, Institute of Clinical Medicine, Faculty of Medicine and Oslo University Hospital, University of Oslo, Oslo, Norway.
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25
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Pyne NJ, Pyne S. Receptor tyrosine kinase-G-protein-coupled receptor signalling platforms: out of the shadow? Trends Pharmacol Sci 2011; 32:443-50. [PMID: 21612832 DOI: 10.1016/j.tips.2011.04.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 04/20/2011] [Accepted: 04/26/2011] [Indexed: 12/29/2022]
Abstract
Receptor tyrosine kinases (RTKs) and G-protein-coupled receptors (GPCRs) can form platforms in which protein signalling components specific for each receptor are shared (owing to close proximity) to produce an integrated response upon engagement of ligands. RTK-GPCR signalling platforms respond to growth factors and GPCR agonists to increase gain over and above that which is normally produced by separate receptors. They can also function to change the spatial context of signalling in response to growth factor activation. The function of RTK-GPCR signalling platforms can be modulated with conformational-specific inhibitors that stabilise defined GPCR states to abrogate both GPCR agonist- and growth factor-stimulated cell responses. In this paper, we provide an opinion of the biology and unusual pharmacology of RTK-GPCR signalling platforms and make comparisons with a more traditional model of crosstalk between RTKs and GPCRs.
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Affiliation(s)
- Nigel J Pyne
- Cell Biology Group, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow, G4 0RE, UK.
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Toumi F, Frankson M, Ward JB, Kelly OB, Mroz MS, Bertelsen LS, Keely SJ. Chronic regulation of colonic epithelial secretory function by activation of G protein-coupled receptors. Neurogastroenterol Motil 2011; 23:178-86, e43. [PMID: 20939850 DOI: 10.1111/j.1365-2982.2010.01610.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Enteric neurotransmitters that act at G protein-coupled receptors (GPCRs) are well known to acutely promote epithelial Cl(-) and fluid secretion. Here we examined if acute GPCR activation might have more long-term consequences for epithelial secretory function. METHODS Cl(-) secretion was measured as changes in short-circuit current across voltage-clamped T(84) colonic epithelial cells. Protein expression was measured by western blotting and intracellular Ca(2+) levels by Fura-2 fluorescence. KEY RESULTS While acute (15 min) treatment of T(84) cells with a cholinergic G(q) PCR agonist, carbachol (CCh), rapidly stimulated Cl(-) secretion, subsequent CCh-induced responses were attenuated in a biphasic manner. The first phase was transient and resolved within 6 h but this was followed by a chronic phase of attenuated responsiveness that was sustained up to 48 h. CCh-pretreatment did not chronically alter responses to another G(q)PCR agonist, histamine, or to thapsigargin or forskolin which elevate intracellular Ca(2+) and cAMP, respectively. This chronically acting antisecretory mechanism is not shared by neurotransmitters that activate G(s)PCRs. Conditioned medium from CCh-pretreated cells mimicked its chronic antisecretory actions, suggesting involvement of an epithelial-derived soluble factor but further experimentation ruled out the involvement of epidermal growth factor receptor ligands. Acute CCh exposure did not chronically alter surface expression of muscarinic M(3) receptors but inhibited intracellular Ca(2+) mobilization upon subsequent agonist challenge. CONCLUSIONS & INFERENCES These data reveal a novel, chronically acting, antisecretory mechanism that downregulates epithelial secretory capacity upon repeated G(q)PCR agonist exposure. This mechanism involves release of a soluble factor that uncouples receptor activation from downstream prosecretory signals.
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Affiliation(s)
- F Toumi
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
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McArt DG, Zhang SD. Identification of candidate small-molecule therapeutics to cancer by gene-signature perturbation in connectivity mapping. PLoS One 2011; 6:e16382. [PMID: 21305029 PMCID: PMC3031567 DOI: 10.1371/journal.pone.0016382] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Accepted: 12/14/2010] [Indexed: 01/16/2023] Open
Abstract
Connectivity mapping is a recently developed technique for discovering the underlying connections between different biological states based on gene-expression similarities. The sscMap method has been shown to provide enhanced sensitivity in mapping meaningful connections leading to testable biological hypotheses and in identifying drug candidates with particular pharmacological and/or toxicological properties. Challenges remain, however, as to how to prioritise the large number of discovered connections in an unbiased manner such that the success rate of any following-up investigation can be maximised. We introduce a new concept, gene-signature perturbation, which aims to test whether an identified connection is stable enough against systematic minor changes (perturbation) to the gene-signature. We applied the perturbation method to three independent datasets obtained from the GEO database: acute myeloid leukemia (AML), cervical cancer, and breast cancer treated with letrozole. We demonstrate that the perturbation approach helps to identify meaningful biological connections which suggest the most relevant candidate drugs. In the case of AML, we found that the prevalent compounds were retinoic acids and PPAR activators. For cervical cancer, our results suggested that potential drugs are likely to involve the EGFR pathway; and with the breast cancer dataset, we identified candidates that are involved in prostaglandin inhibition. Thus the gene-signature perturbation approach added real values to the whole connectivity mapping process, allowing for increased specificity in the identification of possible therapeutic candidates.
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Affiliation(s)
- Darragh G. McArt
- Centre for Cancer Research and Cell Biology (CCRCB), Queen's University Belfast, Belfast, United Kingdom
| | - Shu-Dong Zhang
- Centre for Cancer Research and Cell Biology (CCRCB), Queen's University Belfast, Belfast, United Kingdom
- * E-mail:
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Phospholipase C-η1 is activated by intracellular Ca(2+) mobilization and enhances GPCRs/PLC/Ca(2+) signaling. Cell Signal 2011; 23:1022-9. [PMID: 21262355 DOI: 10.1016/j.cellsig.2011.01.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 01/14/2011] [Indexed: 11/20/2022]
Abstract
Phospholipase C-η1 (PLC-η1) is the most recently identified PLC isotype and is primarily expressed in nerve tissue. However, its functional role is unclear. In the present study, we report for the first time that PLC-η1 acts as a signal amplifier in G protein-coupled receptor (GPCR)-mediated PLC and Ca(2+) signaling. Short-hairpin RNA (shRNA)-mediated knockdown of endogenous PLC-η1 reduced lysophosphatidic acid (LPA)-, bradykinin (BK)-, and PACAP-induced PLC activity in mouse neuroblastoma Neuro2A (N2A) cells, indicating that PLC-η1 participates in GPCR-mediated PLC activation. Interestingly, ionomycin-induced PLC activity was significantly decreased by PLC-η1, but not PLC-η2, knockdown. In addition, we found that intracellular Ca(2+) source is enough for PLC-η1 activation. Furthermore, the IP(3) receptor inhibitor, 2-APB, inhibited LPA-induced PLC activity in control N2A cells, whereas this effect was not observed in PLC-η1 knockdown N2A cells, suggesting a pivotal role of intracellular Ca(2+) mobilization in PLC-η1 activation. Finally, we found that LPA-induced ERK1/2 phosphorylation and expression of the downstream target gene, krox-24, were significantly decreased by PLC-η1 knockdown, and these knockdown effects were abolished by 2-APB. Taken together, our results strongly suggest that PLC-η1 is activated via intracellular Ca(2+) mobilization from the ER, and therefore amplifies GPCR-mediated signaling.
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29
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Edelstein J, Hao T, Cao Q, Morales L, Rockwell P. Crosstalk between VEGFR2 and muscarinic receptors regulates the mTOR pathway in serum starved SK-N-SH human neuroblastoma cells. Cell Signal 2010; 23:239-48. [PMID: 20851763 DOI: 10.1016/j.cellsig.2010.09.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 09/06/2010] [Indexed: 12/20/2022]
Abstract
Muscarinic acetylcholine receptors (mAchRs) are guanosine nucleotide-binding protein (G protein) coupled receptors that crosstalk with receptor tyrosine kinases (RTKs) to signal mitogenic pathways. In particular, mAchRs are known to couple with RTKs for several growth factors to activate the mammalian target of rapamycin (mTOR)/Akt pathway, a regulator of protein synthesis. The RTK for the vascular endothelial growth factor (VEGF), VEGFR2, can signal protein synthesis but whether it cooperates with mAchRs to mediate mTOR activation has not been demonstrated. Using serum starved SK-N-SH neuroblastoma cells, we show that the muscarinic receptor agonists carbachol and pilocarpine enhance the activation of the mTOR substrate p70 S6 Kinase (S6K) and its target ribosomal protein S6 (S6) in a VEGFR2 dependent manner. Treatments with carbachol increased VEGFR2 phosphorylation, suggesting that mAchRs stimulate VEGFR2 transactivation to enhance mTOR signaling. Inhibitor studies revealed that phosphatidylinositol 3 kinase resides upstream from S6K, S6 and Akt phosphorylation while protein kinase C (PKC) functions in an opposing fashion by positively regulating S6K and S6 phosphorylation and suppressing Akt activation. Treatments with the phosphatase inhibitors sodium orthovanadate and okadaic acid increase S6, Akt and to a lesser extent S6K phosphorylation, indicating that tyrosine and serine/threonine dephosphorylation also regulates their activity. However, okadaic acid elicited a far greater increase in phosphorylation, implicating phosphatase 2A as a critical determinant of their function. Finally, pilocarpine but not carbachol induced a time and dose dependent cell death that was associated with caspase activation and oxidative stress but independent of S6K and S6 activation through VEGFR2. Accordingly, our findings suggest that mAchRs crosstalk with VEGFR2 to enhance mTOR activity but signal divergent effects on survival through alternate mechanisms.
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Affiliation(s)
- Jacob Edelstein
- Department of Biological Sciences, Hunter College of The City University of New York, New York, NY 10065, USA
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30
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Ratchford AM, Baker OJ, Camden JM, Rikka S, Petris MJ, Seye CI, Erb L, Weisman GA. P2Y2 nucleotide receptors mediate metalloprotease-dependent phosphorylation of epidermal growth factor receptor and ErbB3 in human salivary gland cells. J Biol Chem 2010; 285:7545-55. [PMID: 20064929 DOI: 10.1074/jbc.m109.078170] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The G protein-coupled receptor P2Y(2) nucleotide receptor (P2Y(2)R) has been shown to be up-regulated in a variety of tissues in response to stress or injury. Recent studies have suggested that P2Y(2)Rs may play a role in immune responses, wound healing, and tissue regeneration via their ability to activate multiple signaling pathways, including activation of growth factor receptors. Here, we demonstrate that in human salivary gland (HSG) cells, activation of the P2Y(2)R by its agonist induces phosphorylation of ERK1/2 via two distinct mechanisms, a rapid, protein kinase C-dependent pathway and a slower and prolonged, epidermal growth factor receptor (EGFR)-dependent pathway. The EGFR-dependent stimulation of UTP-induced ERK1/2 phosphorylation in HSG cells is inhibited by the adamalysin inhibitor tumor necrosis factor-alpha protease inhibitor or by small interfering RNA that selectively silences ADAM10 and ADAM17 expression, suggesting that ADAM metalloproteases are required for P2Y(2)R-mediated activation of the EGFR. G protein-coupled receptors have been shown to promote proteolytic release of EGFR ligands; however, neutralizing antibodies to known ligands of the EGFR did not inhibit UTP-induced EGFR phosphorylation. Immunoprecipitation experiments indicated that UTP causes association of the EGFR with another member of the EGF receptor family, ErbB3. Furthermore, stimulation of HSG cells with UTP induced phosphorylation of ErbB3, and silencing of ErbB3 expression inhibited UTP-induced phosphorylation of both ErbB3 and EGFR. UTP-induced phosphorylation of ErbB3 and EGFR was also inhibited by silencing the expression of the ErbB3 ligand neuregulin 1 (NRG1). These results suggest that P2Y(2)R activation in salivary gland cells promotes the formation of EGFR/ErbB3 heterodimers and metalloprotease-dependent neuregulin 1 release, resulting in the activation of both EGFR and ErbB3.
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Affiliation(s)
- Ann M Ratchford
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, Missouri 65211, USA
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Sánchez-González P, Jellali K, Villalobo A. Calmodulin-mediated regulation of the epidermal growth factor receptor. FEBS J 2009; 277:327-42. [PMID: 19951361 DOI: 10.1111/j.1742-4658.2009.07469.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this review, we first describe the mechanisms by which the epidermal growth factor receptor generates a Ca(2+) signal and, subsequently, we compile the available experimental evidence regarding the role that the Ca(2+)/calmodulin complex, formed after the rise in cytosolic free Ca(2+) concentration, exerts on the receptor. We focus not only on the indirect action that Ca(2+)/calmodulin exerts on the epidermal growth factor receptor, as a result of the activation of distinct calmodulin-dependent kinases, but also, and more extensively, on the direct interaction of Ca(2+)/calmodulin with the receptor. We also describe several mechanistic models that could account for the Ca(2+)/calmodulin-mediated regulation of epidermal growth factor receptor activity. The control exerted by calmodulin on distinct epidermal growth factor receptor-mediated cellular functions is also discussed. Finally, the phosphorylation of this Ca(2+) sensor by the epidermal growth factor receptor is highlighted.
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Affiliation(s)
- Pablo Sánchez-González
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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Resende RR, Adhikari A. Cholinergic receptor pathways involved in apoptosis, cell proliferation and neuronal differentiation. Cell Commun Signal 2009; 7:20. [PMID: 19712465 PMCID: PMC2744676 DOI: 10.1186/1478-811x-7-20] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 08/27/2009] [Indexed: 11/14/2022] Open
Abstract
Acetylcholine (ACh) has been shown to modulate neuronal differentiation during early development. Both muscarinic and nicotinic acetylcholine receptors (AChRs) regulate a wide variety of physiological responses, including apoptosis, cellular proliferation and neuronal differentiation. However, the intracellular mechanisms underlying these effects of AChR signaling are not fully understood. It is known that activation of AChRs increase cellular proliferation and neurogenesis and that regulation of intracellular calcium through AChRs may underlie the many functions of ACh. Intriguingly, activation of diverse signaling molecules such as Ras-mitogen-activated protein kinase, phosphatidylinositol 3-kinase-Akt, protein kinase C and c-Src is modulated by AChRs. Here we discuss the roles of ACh in neuronal differentiation, cell proliferation and apoptosis. We also discuss the pathways involved in these processes, as well as the effects of novel endogenous AChRs agonists and strategies to enhance neuronal-differentiation of stem and neural progenitor cells. Further understanding of the intracellular mechanisms underlying AChR signaling may provide insights for novel therapeutic strategies, as abnormal AChR activity is present in many diseases.
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Affiliation(s)
- Rodrigo R Resende
- Department of Physics, Institute of Exact Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil.
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Cross talk between receptor guanylyl cyclase C and c-src tyrosine kinase regulates colon cancer cell cytostasis. Mol Cell Biol 2009; 29:5277-89. [PMID: 19620276 DOI: 10.1128/mcb.00001-09] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Increased activation of c-src seen in colorectal cancer is an indicator of a poor clinical prognosis, suggesting that identification of downstream effectors of c-src may lead to new avenues of therapy. Guanylyl cyclase C (GC-C) is a receptor for the gastrointestinal hormones guanylin and uroguanylin and the bacterial heat-stable enterotoxin. Though activation of GC-C by its ligands elevates intracellular cyclic GMP (cGMP) levels and inhibits cell proliferation, its persistent expression in colorectal carcinomas and occult metastases makes it a marker for malignancy. We show here that GC-C is a substrate for inhibitory phosphorylation by c-src, resulting in reduced ligand-mediated cGMP production. Consequently, active c-src in colonic cells can overcome GC-C-mediated control of the cell cycle. Furthermore, docking of the c-src SH2 domain to phosphorylated GC-C results in colocalization and further activation of c-src. We therefore propose a novel feed-forward mechanism of activation of c-src that is induced by cross talk between a receptor GC and a tyrosine kinase. Our findings have important implications in understanding the molecular mechanisms involved in the progression and treatment of colorectal cancer.
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Jiang X, Sinnett-Smith J, Rozengurt E. Carbachol induces p70S6K1 activation through an ERK-dependent but Akt-independent pathway in human colonic epithelial cells. Biochem Biophys Res Commun 2009; 387:521-4. [PMID: 19615971 DOI: 10.1016/j.bbrc.2009.07.060] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 07/13/2009] [Indexed: 01/10/2023]
Abstract
Stimulation of human colonic epithelial T84 cells with the muscarinic receptor agonist carbachol, a stable analog of acetylcholine, induced Akt, p70S6K1 and ERK activation. Treatment of T84 cells with the selective inhibitor of EGF receptor (EGFR) tyrosine kinase AG1478 abrogated Akt phosphorylation on Ser(473) induced by either carbachol or EGF, indicating that carbachol-induced Akt activation is mediated through EGFR transactivation. Surprisingly, AG1478 did not suppress p70S6K1 phosphorylation on Thr(389) in response to carbachol, indicating the G protein-coupled receptor (GPCR) stimulation induces p70S6K1 activation, at least in part, via an Akt-independent pathway. In contrast, treatment with the selective MEK inhibitor U0126 (but not with the inactive analog U0124) inhibited carbachol-induced p70S6K1 activation, indicating that the MEK/ERK/RSK pathway plays a critical role in p70S6K1 activation in GPCR-stimulated T84 cells. These findings imply that GPCR activation induces p70S6K1 via ERK rather than through the canonical PI 3-kinase/Akt/TSC/mTORC1 pathway in T84 colon carcinoma cells.
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Affiliation(s)
- Xiaohua Jiang
- Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, David Geffen School of Medicine and Molecular Biology Institute, University of California at Los Angeles, CA 90095, USA
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35
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McCole DF, Barrett KE. Decoding epithelial signals: critical role for the epidermal growth factor receptor in controlling intestinal transport function. Acta Physiol (Oxf) 2009; 195:149-59. [PMID: 18983445 DOI: 10.1111/j.1748-1716.2008.01929.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The intestinal epithelium engages in bidirectional transport of fluid and electrolytes to subserve the physiological processes of nutrient digestion and absorption, as well as the elimination of wastes, without excessive losses of bodily fluids that would lead to dehydration. The overall processes of intestinal ion transport, which in turn drive the secretion or absorption of water, are accordingly carefully regulated. We and others have identified the epidermal growth factor receptor (EGFr) as a critical regulator of mammalian intestinal ion transport. In this article, we focus on our studies that have uncovered the intricate signalling mechanisms downstream of EGFr that regulate both chloride secretion and sodium absorption by colonocytes. Emphasis will be placed on the EGFr-associated regulatory pathways that dictate the precise outcome to receptor activation in response to signals that may seem, on their face, to be quite similar if not identical. The concepts to be discussed underlie the ability of the intestinal epithelium to utilize a limited set of signalling effectors to produce a variety of outcomes suitable for varying physiological and pathophysiological demands. Our findings therefore are relevant not only to basic biological principles, but also may ultimately point to new therapeutic targets in intestinal diseases where ion transport is abnormal.
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Affiliation(s)
- D F McCole
- Department of Medicine, Division of Gastroenterology, University of California, San Diego, La Jolla, CA, USA
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36
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Krimi RB, Kotelevets L, Dubuquoy L, Plaisancié P, Walker F, Lehy T, Desreumaux P, Van Seuningen I, Chastre E, Forgue-Lafitte ME, Marie JC. Resistin-like molecule beta regulates intestinal mucous secretion and curtails TNBS-induced colitis in mice. Inflamm Bowel Dis 2008; 14:931-41. [PMID: 18300276 DOI: 10.1002/ibd.20420] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND Resistin and resistin-like molecule (RELM)beta comprise a novel class of cysteine-rich proteins secreted into the circulation implicated in hepatic insulin resistance and inflammation. RELMbeta is specifically produced by intestinal goblet cells but regulation of its expression and much of its local function are not elucidated. RELMbeta has been suggested to regulate colonic inflammation susceptibility, which is dependent on the mucosal barrier integrity. METHODS In this work we explored the physiopathological role of RELMbeta in the colon. Among agents tested, carbachol and gastrin were strong inhibitors of RELMbeta mRNA accumulation. We examined the effect of recombinant RELMbeta on mucin secretion by human mucus-secreting HT29-Cl.16E cells in culture and by mouse colonic goblet cells in vivo. RESULTS RELMbeta upregulated MUC2 and M1/MUC5AC gene expression in HT29-Cl.16E cells. RELMbeta enhanced M1/MUC5AC secretion by human colonic HT29-Cl.16E cells and MUC2 secretion by murine intestinal goblet cells. RELMbeta exerted its action exclusively on the apical side of HT29-Cl.16E cells, in agreement with its luminal mucosecretagogue effect in mice. Its action required calcium, protein kinase C, tyrosine kinases, and extracellular-regulated protein kinase activities and was synergized by carbachol. An intracolonic RELMbeta challenge was performed in the trinitrobenzene sulfonic acid (TNBS)-murine model of colitis and macroscopic and histological scores were monitored. The macroscopic and histopathological severity of TNBS-induced colitis was significantly attenuated by RELMbeta pretreatment. CONCLUSIONS A direct participation in maintaining the mucosal defense barrier can be ascribed to RELMbeta in line with a regulatory role in intestinal inflammation.
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Affiliation(s)
- Rim Belharbi Krimi
- INSERM, U773, Centre de Recherche Biomédicale Bichat Beaujon CRB3, Paris, France
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Nathanson NM. Synthesis, trafficking, and localization of muscarinic acetylcholine receptors. Pharmacol Ther 2008; 119:33-43. [PMID: 18558434 DOI: 10.1016/j.pharmthera.2008.04.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 04/28/2008] [Indexed: 12/27/2022]
Abstract
Muscarinic acetylcholine receptors are members of the G-protein coupled receptor superfamily that are expressed in and regulate the function of neurons, cardiac and smooth muscle, glands, and many other cell types and tissues. The correct trafficking of membrane proteins to the cell surface and their subsequent localization at appropriate sites in polarized cells are required for normal cellular signaling and physiological responses. This review will summarize work on the synthesis and trafficking of muscarinic receptors to the plasma membrane and their localization at the cell surface.
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Affiliation(s)
- Neil M Nathanson
- Department of Pharmacology, School of Medicine, University of Washington, Box 357750, Seattle, WA 98195-7750, USA.
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Lin AL, Zhu B, Zhang W, Dang H, Zhang BX, Katz MS, Yeh CK. Distinct pathways of ERK activation by the muscarinic agonists pilocarpine and carbachol in a human salivary cell line. Am J Physiol Cell Physiol 2008; 294:C1454-64. [PMID: 18385290 DOI: 10.1152/ajpcell.00151.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cholinergic-muscarinic receptor agonists are used to alleviate mouth dryness, although the cellular signals mediating the actions of these agents on salivary glands have not been identified. We examined the activation of ERK1/2 by two muscarinic agonists, pilocarpine and carbachol, in a human salivary cell line (HSY). Immunoblot analysis revealed that both agonists induced transient activation of ERK1/2. Whereas pilocarpine induced phosphorylation of the epidermal growth factor (EGF) receptor, carbachol did not. Moreover, ERK activation by pilocarpine, but not carbachol, was abolished by the EGF receptor inhibitor AG-1478. Downregulation of PKC by prolonged treatment of cells with the phorbol ester PMA diminished carbachol-induced ERK phosphorylation but had no effect on pilocarpine responsiveness. Depletion of intracellular Ca2+ ([Ca2+]i by EGTA did not affect ERK activation by either agent. In contrast to carbachol, pilocarpine did not elicit [Ca2+]i mobilization in HSY cells. Treatment of cells with the muscarinic receptor subtype 3 (M3) antagonist N-(3-chloropropyl)-4-piperidnyl diphenylacetate decreased ERK responsiveness to both agents, whereas the subtype 1 (M1) antagonist pirenzepine reduced only the carbachol response. Stimulation of ERKs by pilocarpine was also decreased by M3, but not M1, receptor small interfering RNA. The Src inhibitor PP2 blocked pilocarpine-induced ERK activation and EGF receptor phosphorylation, without affecting ERK activation by carbachol. Our results demonstrate that the actions of pilocarpine and carbachol in salivary cells are mediated through two distinct signaling mechanisms-pilocarpine acting via M3 receptors and Src-dependent transactivation of EGF receptors, and carbachol via M1/M3 receptors and PKC-converging on the ERK pathway.
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Affiliation(s)
- Alan L Lin
- Department of Dental Diagnostic Science, University of Texas Health Science Center, San Antonio, TX, USA
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van der Merwe JQ, Hollenberg MD, MacNaughton WK. EGF receptor transactivation and MAP kinase mediate proteinase-activated receptor-2-induced chloride secretion in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2008; 294:G441-51. [PMID: 18032480 DOI: 10.1152/ajpgi.00303.2007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We examined the stimulus-secretion pathways whereby proteinase-activated receptor 2 (PAR-2) stimulates Cl(-) secretion in intestinal epithelial cells. SCBN and T84 epithelial monolayers grown on Snapwell supports and mounted in modified Ussing chambers were activated by the PAR-2-activating peptides SLIGRL-NH(2) and 2-furoyl-LIGRLO-NH(2). Short-circuit current (I(sc)) was used as a measure of net electrogenic ion transport. Basolateral, but not apical, application of SLIGRL-NH(2) or 2-furoyl-LIGRLO-NH(2) caused a concentration-dependent change in I(sc) that was significantly reduced in Cl(-)-free buffer and by the intracellular Ca(2+) blockers thapsigargin and BAPTA-AM, but not by the Ca(2+) channel blocker verapamil. Inhibitors of PKA (H-89) and CFTR (glibenclamide) also significantly reduced PAR-2-stimulated Cl(-) transport. PAR-2 activation was associated with increases in cAMP and intracellular Ca(2+). Immunoblot analysis revealed increases in phosphorylation of epidermal growth factor (EGF) receptor (EGFR) tyrosine kinase, Src, Pyk2, cRaf, and ERK1/2 in response to PAR-2 activation. Pretreatment with inhibitors of cyclooxygenases (indomethacin), tyrosine kinases (genistein), EGFR (PD-153035), MEK (PD-98059 or U-0126), and Src (PP1) inhibited SLIGRL-NH(2)-induced increases in I(sc). Inhibition of Src, but not matrix metalloproteinases, reduced EGFR phosphorylation. Reduced EGFR phosphorylation paralleled the reduction in PAR-2-stimulated I(sc). We conclude that activation of basolateral, but not apical, PAR-2 induces epithelial Cl(-) secretion via cAMP- and Ca(2+)-dependent mechanisms. The secretory effect involves EGFR transactivation by Src, leading to subsequent ERK1/2 activation and increased cyclooxygenase activity.
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Affiliation(s)
- Jacques Q van der Merwe
- Inflammation Research Network, Department of Physiology, University of Calgary, Calgary, AB, Canada T2N 4N1
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40
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Chappell AE, Bunz M, Smoll E, Dong H, Lytle C, Barrett KE, McCole DF. Hydrogen peroxide inhibits Ca2+-dependent chloride secretion across colonic epithelial cells via distinct kinase signaling pathways and ion transport proteins. FASEB J 2008; 22:2023-36. [PMID: 18211955 DOI: 10.1096/fj.07-099697] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Reactive oxygen species (ROS) are key mediators in a number of inflammatory conditions, including inflammatory bowel disease (IBD). ROS, including hydrogen peroxide (H(2)O(2)), modulate intestinal epithelial ion transport and are believed to contribute to IBD-associated diarrhea. Intestinal crypt fluid secretion, driven by electrogenic Cl(-) secretion, hydrates and sterilizes the crypt, thus reducing bacterial adherence. Here, we show that pathophysiological concentrations of H(2)O(2) inhibit Ca(2+)-dependent Cl(-) secretion across T(84) colonic epithelial cells by elevating cytosolic Ca(2+), which contributes to activation of two distinct signaling pathways. One involves recruitment of the Ca(2+)-responsive kinases, Src and Pyk-2, as well as extracellular signal-regulated kinase (ERK). A separate pathway recruits p38 MAP kinase and phosphoinositide 3-kinase (PI3-K) signaling. The ion transport response to Ca(2+)-dependent stimuli is mediated in part by K(+) efflux through basolateral K(+) channels and Cl(-) uptake by the Na(+)-K(+)-2Cl(-) cotransporter, NKCC1. We demonstrate that H(2)O(2) inhibits Ca(2+)-dependent basolateral K(+) efflux and also inhibits NKCC1 activity independently of inhibitory effects on apical Cl(-) conductance. Thus, we have demonstrated that H(2)O(2) inhibits Ca(2+)-dependent Cl(-) secretion through multiple negative regulatory signaling pathways and inhibition of specific ion transporters. These findings increase our understanding of mechanisms by which inflammation disturbs intestinal epithelial function and contributes to intestinal pathophysiology.
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Affiliation(s)
- Alfred E Chappell
- Division of Gastroenterology, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0063, USA
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Hodges RR, Horikawa Y, Rios JD, Shatos MA, Dartt DA. Effect of protein kinase C and Ca(2+) on p42/p44 MAPK, Pyk2, and Src activation in rat conjunctival goblet cells. Exp Eye Res 2007; 85:836-44. [PMID: 17919561 DOI: 10.1016/j.exer.2007.08.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Revised: 03/21/2007] [Accepted: 08/23/2007] [Indexed: 11/29/2022]
Abstract
Conjunctival goblet cells synthesize and secrete mucins onto the ocular surface to lubricate it and protect it from bacterial infections. Mucin secretion is under neural control, and cholinergic agonists released from parasympathetic nerves are major stimuli of this secretion. The signal transduction pathways these agonists use to stimulate secretion involve activating protein kinase C (PKC) and increasing intracellular [Ca(2+)] to activate the non-receptor kinases Pyk2 and p60Src (Src) to transactivate the EGF receptor. Transactivation of the EGF receptor activates a kinase cascade culminating in the activation of p42/p44 MAPK (MAPK) and ultimately that leads to secretion of high molecular weight glycocongujates (HMWGC), including mucins. To further examine the roles of PKC and Ca(2+) in the activation of MAPK, Pyk2, and Src in mucin secretion, rat conjunctival pieces and cultured goblet cells were incubated with the PKC activator phorbol myristate acid (PMA), the cholinergic agonist carbachol, or the calcium ionophore, ionomycin for varying times. Conjunctival pieces were preincubated with PKC inhibitors 10min prior to addition of carbachol (10(-4)M) for 10min. The amount of phosphorylated (activated) MAPK, Pyk2 and Src was determined by Western blotting techniques using antibodies specific to the phosphorylated forms of each kinase. PMA significantly increased the activation of MAPK, Pyk2, and Src in a time and concentration-dependent manner. PMA-stimulated MAPK activity was completely inhibited by the EGF receptor inhibitor AG1478 (10(-7)M). Carbachol-stimulated MAPK activity was inhibited by three PKC inhibitors, calphostin C, chelethyrine, and staurosporine. Ionomycin (10(-6)M)-stimulated MAPK activity was inhibited 66% by AG1478 (10(-7)M). Ionomycin also significantly increased Pyk2 and Src in time dependent manner. PKC and ionomycin also activated p42/p44 MAPK, Pyk2, and Src in cultured conjunctival goblet cells. We conclude that PKC and intracellular Ca(2+) activate Pyk2 and Src and phosphorylate the EGF receptor leading to stimulation of MAPK in conjunctival goblet cells.
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Affiliation(s)
- Robin R Hodges
- Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA.
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Buffin-Meyer B, Crassous PA, Delage C, Denis C, Schaak S, Paris H. EGF receptor transactivation and PI3-kinase mediate stimulation of ERK by alpha(2A)-adrenoreceptor in intestinal epithelial cells: a role in wound healing. Eur J Pharmacol 2007; 574:85-93. [PMID: 17655843 DOI: 10.1016/j.ejphar.2007.07.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2007] [Revised: 07/02/2007] [Accepted: 07/05/2007] [Indexed: 12/11/2022]
Abstract
Intestinal cells express alpha(2A)-adrenoreceptors that stimulate sodium and peptide absorption and promote cell proliferation. Involved mechanisms are poorly understood and are not fully related to inhibition of cAMP production. Previous study using a clone of CaCo2 cells expressing the human alpha(2A)-adrenoreceptor (CaCo2-3B) showed that alpha(2)-adrenoreceptor agonists cause extracellular signal-regulated kinase (ERK) phosphorylation. Present work examines the signaling pathway triggering ERK activation and investigates the consequence of alpha(2A)-adrenoreceptor stimulation on cell migration. Treatment of CaCo2-3B with the alpha(2)-adrenoreceptor agonist 5-bromo-6-(2-imidazolin-2-ylamino) quinoxaline (UK14304) induces not only ERK, but also Akt phosphorylation. Both effects are strongly attenuated by inhibition or desensitization of epidermal growth factor (EGF) receptor, matrix metalloproteinase (MMP) blockade, heparin-binding-EGF neutralization or phosphatidylinositol 3-kinase (PI3-kinase) inhibitors. Conditioned medium from UK14304-treated CaCo2-3B stimulates ERK in parental CaCo2 by a mechanism sensitive to EGF receptor and PI3-kinase inhibitors. Exposure of CaCo2-3B to UK14304 accelerates the wound healing. This effect is abolished by heparin-binding-EGF neutralization but not by mitomycin C, indicating that it results probably from increased cell spreading and/or migration. In conclusion, alpha(2A)-adrenoreceptor activates ERK and Akt in intestinal cells by a common pathway which depends on PI3-kinase activation and results from EGF receptor transactivation, via an autocrine/paracrine pathway implying MMP activation and heparin-binding-EGF shedding. Therefore, alpha(2A)-adrenoreceptor could have a positive role in intestinal regeneration in vivo.
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Affiliation(s)
- Bénédicte Buffin-Meyer
- INSERM, U858/I2MR, Department of Renal and Cardiac remodelling, team #5, 1 avenue Jean Poulhès, BP 84225, 31432 Toulouse Cedex 4, France.
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43
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Zandi R, Larsen AB, Andersen P, Stockhausen MT, Poulsen HS. Mechanisms for oncogenic activation of the epidermal growth factor receptor. Cell Signal 2007; 19:2013-23. [PMID: 17681753 DOI: 10.1016/j.cellsig.2007.06.023] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 06/14/2007] [Indexed: 10/23/2022]
Abstract
The Epidermal growth factor receptor (EGFR) is a membrane spanning glycoprotein, which frequently has been implicated in various cancer types. The mechanisms by which EGFR becomes oncogenic are numerous and are often specific for each cancer type. In some tumors, EGFR is activated by autocrine/paracrine growth factor loops, whereas in others activating mutations promote EGFR signaling. Overexpression and/or amplification of the EGFR gene are prevalent in many cancer types leading to aberrant EGFR signaling. In addition, failure to attenuate receptor signaling by receptor downregulation can also lead to cellular transformation. Heterodimerization of EGFR with ErbB2 inhibits downregulation of EGFR and thereby prolongs growth factor signaling. This also indicates that cross-talk between EGFR and heterologous receptor systems serves as another mechanism for oncogenic activation of EGFR. Because of its role in tumor promotion, the EGFR has been intensely studied as a therapeutic target. There are currently two major mechanisms by which the EGFR is targeted: antibodies binding to the extracellular domain of EGFR and small-molecule tyrosine-kinase inhibitors. However, tumorigenesis is a multi-step process involving several mutations, which might explain why EGFR therapeutics has only been partially successful. This highlights the importance of pinpointing the mechanisms by which EGFR becomes oncogenic in a particular cancer. In this review, each of the above mentioned mechanisms will be discussed, as a detailed molecular and genetic understanding of how EGFR contributes to the malignant phenotype might offer new promise for the design, development and clinical evaluation of future tumor-specific anticancer approaches.
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Affiliation(s)
- Roza Zandi
- Department of Radiation Biology, The Finnsen Centre, Copenhagen University Hospital, 9 Blegdamsvej, DK-2100 Copenhagen, Denmark
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44
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Azar ZM, Mehdi MZ, Srivastava AK. Insulin-like growth factor type-1 receptor transactivation in vasoactive peptide and oxidant-induced signaling pathways in vascular smooth muscle cells. Can J Physiol Pharmacol 2007; 85:105-11. [PMID: 17487250 DOI: 10.1139/y06-101] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Transactivation of epidermal growth factor receptor (EGFR) is a well-documented mechanism by which vasoactive peptides and H2O2 elicit their cellular responses. However, a role for the insulin-like growth factor type-1 receptor (IGF-1R) transactivation in mediating the effects of angiotensin II (Ang II) and H2O2 in vascular smooth muscle cells from different artery types have also been recently recognized. By using a series of pharmacological inhibitors of various growth factor receptor tyrosine kinases and a direct analysis of the phosphorylation status of the beta-subunit of IGF-1R, a requirement of this growth factor receptor in Ang II and H2O2 response has been demonstrated. This review discusses some of the studies that highlight the importance of IGF-1R transactivation in mediating Ang II- and H2O2-induced mitogen-activated protein kinase and protein kinase B signaling pathways.
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MESH Headings
- Angiotensin II/metabolism
- Animals
- Arteries/metabolism
- Humans
- Hydrogen Peroxide/pharmacology
- Mitogen-Activated Protein Kinases/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Oxidants/pharmacology
- Oxidative Stress/drug effects
- Phosphorylation
- Protein Kinase Inhibitors/pharmacology
- Proto-Oncogene Proteins c-akt/metabolism
- Reactive Oxygen Species/metabolism
- Receptor, IGF Type 1/antagonists & inhibitors
- Receptor, IGF Type 1/metabolism
- Receptors, G-Protein-Coupled/metabolism
- Signal Transduction/drug effects
- Vasoconstrictor Agents/metabolism
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Affiliation(s)
- Zeina M Azar
- Montreal Diabetes Research Centre, Centre hospitalier de l'Université de Montréal (CHUM)- Angus Campus and Department of Medicine, Université de Montréal, 2901, Rachel East, Montreal, QC H1W 4A4, Canada
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Huang J, Hu J, Bian X, Chen K, Gong W, Dunlop NM, Howard OMZ, Wang JM. Transactivation of the epidermal growth factor receptor by formylpeptide receptor exacerbates the malignant behavior of human glioblastoma cells. Cancer Res 2007; 67:5906-13. [PMID: 17575160 DOI: 10.1158/0008-5472.can-07-0691] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The G protein-coupled formylpeptide receptor (FPR), which mediates leukocyte migration in response to bacterial and host-derived chemotactic peptides, promotes the chemotaxis, survival, and tumorigenesis of highly malignant human glioblastoma cells. Because glioblastoma cells may also express other receptors for growth signals, such as the epidermal growth factor (EGF) receptor (EGFR), we investigated the role of EGFR in the signaling cascade of FPR and how two receptors cross-talk to exacerbate tumor growth. We found that N-formyl-methionyl-leucyl-phenylalanine, an FPR agonist peptide, rapidly induced EGFR phosphorylation at tyrosine residue (Tyr) 992, but not residues 846, 1068, or 1173, in glioblastoma cells, whereas all these residues were phosphorylated after only EGF treatment. The FPR agonist-induced EGFR phosphorylation in tumor cells was dependent on the presence of FPR as well as Galphai proteins, and was controlled by Src tyrosine kinase. The transactivation of EGFR contributes to the biological function of FPR in glioblastoma cells because inhibition of EGFR phosphorylation significantly reduced FPR agonist-induced tumor cell chemotaxis and proliferation. Furthermore, depletion of both FPR and EGFR by short interference RNA abolished the tumorigenesis of the glioblastoma cells. Our study indicates that the glioblastoma-promoting activity of FPR is mediated in part by transactivation of EGFR and the cross-talk between two receptors exacerbates the malignant phenotype of tumor cells. Thus, targeting both receptors may yield antiglioblastoma agents superior to those targeting one of them.
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Affiliation(s)
- Jian Huang
- Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Science Applications International Corporation-Frederick, National Cancer Institute at Frederick, Frederick, Maryland 21702-1201, USA
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46
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Reynolds A, Parris A, Evans LA, Lindqvist S, Sharp P, Lewis M, Tighe R, Williams MR. Dynamic and differential regulation of NKCC1 by calcium and cAMP in the native human colonic epithelium. J Physiol 2007; 582:507-24. [PMID: 17478539 PMCID: PMC2075325 DOI: 10.1113/jphysiol.2007.129718] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The capacity of the intestine to secrete fluid is dependent on the basolateral Na(+)-K(+)-2Cl(-) co-transporter (NKCC1). Given that cAMP and Ca(2+) signals promote sustained and transient episodes of fluid secretion, respectively, this study investigated the differential regulation of functional NKCC1 membrane expression in the native human colonic epithelium. Tissue sections and colonic crypts were obtained from sigmoid rectal biopsy tissue samples. Cellular location of NKCC1, Na(+)-K(+)-ATPase, M3 muscarinic acetylcholine receptor (M(3)AChR) and lysosomes was examined by immunolabelling techniques. NKCC1 activity (i.e. bumetanide-sensitive uptake), intracellular Ca(2+) and cell volume were assessed by 2',7'-bis(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF), Fura-2 and differential interference contrast/calcein imaging. Unstimulated NKCC1 was expressed on basolateral membranes and exhibited a topological expression gradient, predominant at the crypt base. Cholinergic Ca(2+) signals initiated at the crypt base and spread along the crypt axis. In response, NKCC1 underwent a Ca(2+)-dependent 4 h cycle of recruitment to basolateral membranes, activation, internalization, degradation and re-expression. Internalization was prevented by the epidermal growth factor receptor kinase inhibitor tyrphostin-AG1478, and re-expression was prohibited by the protein synthesis inhibitor cylcoheximide; the lysosome inhibitor chloroquine promoted accumulation of NKCC1 vesicles. NKCC1 internalization and re-expression were accompanied by secretory volume decrease and bumetanide-sensitive regulatory volume increase, respectively. In contrast, forskolin (i.e. cAMP elevation)-stimulated NKCC1 activity was sustained, and membrane expression and cell volume remained constant. Co-stimulation with forskolin and acetylcholine promoted dramatic recruitment of NKCC1 to basolateral membranes and prolonged the cycle of co-transporter activation, internalization and re-expression. In conclusion, persistent NKCC1 activation by cAMP is constrained by a Ca(2+)-dependent cycle of co-transporter internalization, degradation and re-expression; this is a novel mechanism to limit intestinal fluid loss.
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Affiliation(s)
- Amy Reynolds
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk NR4 7TJ, UK
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47
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Santiskulvong C, Rozengurt E. Protein kinase Calpha mediates feedback inhibition of EGF receptor transactivation induced by Gq-coupled receptor agonists. Cell Signal 2007; 19:1348-57. [PMID: 17307332 DOI: 10.1016/j.cellsig.2007.01.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 01/11/2007] [Accepted: 01/11/2007] [Indexed: 11/28/2022]
Abstract
While a great deal of attention has been focused on G-protein-coupled receptor (GPCR)-induced epidermal growth factor receptor (EGFR) transactivation, it has been known for many years that the tyrosine kinase activity of the EGFR is inhibited in cells treated with tumor-promoting phorbol esters, a process termed EGFR transmodulation. Because many GPCR agonists that elicit EGFR transactivation also stimulate the Gq/phospholipase C (PLC)/protein kinase C (PKC) pathway, we hypothesized that PKC-mediated inhibition of EGFR transactivation operates physiologically as a feedback loop that regulates the intensity and/or duration of GPCR-elicited EGFR transactivation. In support of this hypothesis, we found that treatment of intestinal epithelial IEC-18 cells with the PKC inhibitors GF 109203X or Ro 31-8220 or chronic exposure of these cells to phorbol-12,13-dibutyrate (PDB) to downregulate PKCs, markedly enhanced the increase in EGFR tyrosine phosphorylation induced by angiotensin II or vasopressin in these cells. Similarly, PKC inhibition enhanced EGFR transactivation in human colonic epithelial T84 cells stimulated with carbachol, as well as in bombesin-stimulated Rat-1 fibroblasts stably transfected with the bombesin receptor. Furthermore, cell treatment with inhibitors with greater specificity towards PKCalpha, including Gö6976, Ro 31-7549 or Ro 32-0432, also increased GPCR-induced EGFR transactivation in IEC-18, T84 and Rat-1 cells. Transfection of siRNAs targeting PKCalpha also enhanced bombesin-induced EGFR tyrosine phosphorylation in Rat-1 cells. Thus, multiple lines of evidence support the hypothesis that conventional PKC isoforms, especially PKCalpha, mediate feedback inhibition of GPCR-induced EGFR transactivation.
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Affiliation(s)
- Chintda Santiskulvong
- Department of Medicine, School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, CA 90095-1786, United States
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48
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Mehdi MZ, Azar ZM, Srivastava AK. Role of receptor and nonreceptor protein tyrosine kinases in H2O2-induced PKB and ERK1/2 signaling. Cell Biochem Biophys 2007; 47:1-10. [PMID: 17406055 DOI: 10.1385/cbb:47:1:1] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
Excessive generation of reactive oxygen species (ROS) has been implicated in the pathogenesis of many diseases, including atherosclerosis, hypertension, and vascular complications of diabetes. However, the precise mechanisms by which ROS contribute to the development of these diseases are not fully characterized. Hydrogen peroxide (H2O2), a ROS, has been shown to activate several signaling protein kinases, such as extracellular signal-regulated kinase (ERK)1/2 and protein kinase B (PKB) in different cell types, notably in vascular smooth muscle cells. Because these pathways regulate cellular mitogenesis, migration, proliferation, survival, and death responses, their aberrant activation has been suggested to be a potential mechanism of ROS-induced pathologies. The upstream elements responsible for H2O2-induced ERK1/2 and PKB activation remain poorly characterized, but a potential role of receptor and nonreceptor protein tyrosine kinases (PTKs) as triggers that initiate such events has been postulated. Therefore, the aim of this review is to highlight the involvement of receptor and nonreceptor PTKs in modulating H2O2-induced ERK1/2 and PKB signaling.
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Affiliation(s)
- Mohamad Z Mehdi
- Laboratory of Cell Signaling, Research Centre, Centre hospitalier de l'Université de Montréal-Technopole Angus, Université de Montréal, Montreal (Quebec) Canada
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49
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Korosec B, Glavac D, Rott T, Ravnik-Glavac M. Alterations in the ATP2A2 gene in correlation with colon and lung cancer. ACTA ACUST UNITED AC 2006; 171:105-11. [PMID: 17116488 DOI: 10.1016/j.cancergencyto.2006.06.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Revised: 06/23/2006] [Accepted: 06/27/2006] [Indexed: 11/22/2022]
Abstract
Sarcoendoplasmic reticulum calcium transport ATPases (SERCA-type calcium pumps), proteins that accumulate calcium in the endoplasmic reticulum, play an important role in numerous signaling pathways controlling tumor growth, differentiation, and cell death. Reports that Atp2a2 (Serca2) haploinsufficient mice often developed cancer prompted us to study the involvement of the ATP2A2 gene in human cancer development. We found 13 different novel alterations of the ATP2A2 gene in 27 of 416 alleles of patients with two different types of cancer. Changes in ATP2A2 were significantly more common in patients with colon cancer (P < 0.0001, odds ratio OR = 25.3) or lung cancer (P = 0.046, OR = 8.05). The 13 alterations were missense mutations (2), intronic deletions (2), intronic insertions (1), and single-nucleotide alterations (8: two in the coding region, three in the intronic region, and three in the promoter region). We detected lost or reduced expression of ATP2A2 in all patients with alterations in the promoter region, as well as in patients with a combination of gene alterations. Our results suggest that germline alterations of ATP2A2 may predispose to lung and colon cancer and that an impaired ATP2A2 gene might be involved, directly or indirectly, as an early event in carcinogenesis.
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Affiliation(s)
- Branka Korosec
- Department of Molecular Genetics, Institute of Pathology, Faculty of Medicine, University of Ljubljana, Korytkova 2, Ljubljana, Slovenia
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50
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Mojsilovic-Petrovic J, Jeong GB, Crocker A, Arneja A, David S, Russell D, Kalb RG. Protecting motor neurons from toxic insult by antagonism of adenosine A2a and Trk receptors. J Neurosci 2006; 26:9250-63. [PMID: 16957081 PMCID: PMC6674510 DOI: 10.1523/jneurosci.1856-06.2006] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The death of motor neurons in amyotrophic lateral sclerosis (ALS) is thought to result from the interaction of a variety of factors including excitotoxicity, accumulation of toxic proteins, and abnormal axonal transport. Previously, we found that the susceptibility of motor neurons to excitotoxic insults can be limited by inhibiting signals evoked by brain-derived neurotrophic factor (BDNF) activation of the receptor tyrosine kinase B (TrkB). Here we show that this can be achieved by direct kinase inhibition or by blockade of a transactivation pathway that uses adenosine A2a receptors and src-family kinases (SFKs). Downstream signaling cascades (such as mitogen-activated protein kinase and phosphatidylinositol-3 kinase) are inhibited by these blockers. In addition to protecting motor neurons from excitotoxic insult, these agents also prevent toxicity that follows from the expression of mutant proteins (G85R superoxide dismutase 1; G59S p150(glued)) that cause familial motor neuron disease. TrkB, adenosine A2a receptors, and SFKs associate into complexes in lipid raft and nonlipid raft membranes and the signaling from lipids rafts may be particularly important because their disruption by cholesterol depletion blocks the ability of BDNF to render motor neurons vulnerable to insult. The neuroprotective versatility of Trk antagonism suggests that it may have broad utility in the treatment of ALS patients.
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Affiliation(s)
- Jelena Mojsilovic-Petrovic
- Department of Neurology, Children’s Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104
| | - Goo-Bo Jeong
- Department of Neurology, Children’s Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104
- Department of Anatomy, College of Medicine, Chungbuk National University, Cheong-ju 361-763, Republic of Korea, and
| | - Amanda Crocker
- Department of Neurology, Children’s Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104
| | - Amrita Arneja
- Department of Neurology, Children’s Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104
| | - Samuel David
- Department of Neurology, Children’s Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104
| | - David Russell
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut 06519
| | - Robert G. Kalb
- Department of Neurology, Children’s Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104
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