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Yin L, Gao M, Xu L, Qi Y, Han L, Peng J. Single-cell analysis of cellular heterogeneity and interactions in the ischemia-reperfusion injured mouse intestine. J Pharm Anal 2023; 13:760-775. [PMID: 37577387 PMCID: PMC10422115 DOI: 10.1016/j.jpha.2023.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 01/12/2023] [Accepted: 02/01/2023] [Indexed: 02/10/2023] Open
Abstract
Nine major cell populations among 46,716 cells were identified in mouse intestinal ischemia‒reperfusion (II/R) injury by single-cell RNA sequencing. For enterocyte cells, 11 subclusters were found, in which enterocyte cluster 1 (EC1), enterocyte cluster 3 (EC3), and enterocyte cluster 8 (EC8) were newly discovered cells in ischemia 45 min/reperfusion 720 min (I 45 min/R 720 min) group. EC1 and EC3 played roles in digestion and absorption, and EC8 played a role in cell junctions. For TA cells, after ischemia 45 min/reperfusion 90 min (I 45 min/R 90 min), many TA cells at the stage of proliferation were identified. For Paneth cells, Paneth cluster 3 was observed in the resting state of normal jejunum. After I 45 min/R 90 min, three new subsets were found, in which Paneth cluster 1 had good antigen presentation activity. The main functions of goblet cells were to synthesize and secrete mucus, and a novel subcluster (goblet cluster 5) with highly proliferative ability was discovered in I 45 min/R 90 min group. As a major part of immune system, the changes in T cells with important roles were clarified. Notably, enterocyte cells secreted Guca2b to interact with Gucy2c receptor on the membranes of stem cells, TA cells, Paneth cells, and goblet cells to elicit intercellular communication. One marker known as glutathione S-transferase mu 3 (GSTM3) affected intestinal mucosal barrier function by adjusting mitogen-activated protein kinases (MAPK) signaling during II/R injury. The data on the heterogeneity of intestinal cells, cellular communication and the mechanism of GSTM3 provide a cellular basis for treating II/R injury.
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Affiliation(s)
- Lianhong Yin
- College of Pharmacy, Dalian Medical University, Dalian, Liaoning, 116044, China
| | - Meng Gao
- College of Pharmacy, Dalian Medical University, Dalian, Liaoning, 116044, China
| | - Lina Xu
- College of Pharmacy, Dalian Medical University, Dalian, Liaoning, 116044, China
| | - Yan Qi
- College of Pharmacy, Dalian Medical University, Dalian, Liaoning, 116044, China
| | - Lan Han
- School of Pharmacy, Anhui University of Chinese Medicine, Hefei, 230012, China
| | - Jinyong Peng
- College of Pharmacy, Dalian Medical University, Dalian, Liaoning, 116044, China
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2
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Zeng C, Xia T, Zheng S, Liang L, Chen Y. Synergistic Effect of Uroguanylin and D 1 Dopamine Receptors on Sodium Excretion in Hypertension. J Am Heart Assoc 2022; 11:e022827. [PMID: 35229618 PMCID: PMC9075328 DOI: 10.1161/jaha.121.022827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Background Oral NaCl produces a greater natriuresis and diuresis than the intravenous infusion of the same amount of NaCl, indicating the existence of a gastro‐renal axis. As one of the major natriuretic hormones secreted by both the intestines and the kidney, we hypothesized that renal uroguanylin interacts with dopamine receptors to increase sodium excretion synergistically, an impaired interaction of which may be involved in the pathogenesis of hypertension. Methods and Results In Wistar‐Kyoto rats, the infusion of uroguanylin or fenoldopam (a D1‐like receptor agonist) induced natriuresis and diuresis. Although subthreshold dosages of uroguanylin or fenoldopam had no effect, the coinfusion of subthreshold dosages of those reagents significantly increased sodium excretion. The coinfusion of an antagonist against D1‐like receptors, SCH23390, or an antagonist against uroguanylin, 2‐methylthioadenosine triphosphate, prevented the fenoldopam‐ or uroguanylin‐mediated natriuresis and diuresis in Wistar‐Kyoto rats. However, the natriuretic effects of uroguanylin and fenoldopam were not observed in spontaneously hypertensive rats. The uroguanylin/D1‐like receptor interaction was also confirmed in renal proximal tubule cells. In renal proximal tubule cells from Wistar‐Kyoto rats but not spontaneously hypertensive rats, stimulation of either D1‐like receptors or uroguanylin inhibited Na+‐K+‐ATPase activity, an effect that was blocked in the presence of SCH23390 or 2‐methylthioadenosine triphosphate. In renal proximal tubule cells from Wistar‐Kyoto rats, guanylyl cyclase C receptor (uroguanylin receptor) and D1 receptor coimmunoprecipitated, which was increased after stimulation by either uroguanylin or fenoldopam; stimulation of one receptor increased renal proximal tubule cell membrane expression of the other. Conclusions These data suggest that there is synergism between uroguanylin and D1‐like receptors to increase sodium excretion. An aberrant interaction between the renal uroguanylin and D1‐like receptors may play a role in the pathogenesis of hypertension.
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Affiliation(s)
- Cindy Zeng
- Department of Cardiology of Chongqing General Hospital Cardiovascular Research Center of Chongqing CollegeUniversity of Chinese Academy of Sciences Chongqing P. R. China
| | - Tianyang Xia
- Department of Cardiology, Daping Hospital The Third Military Medical University Chongqing P. R. China.,Chongqing Key Laboratory for Hypertension Research Chongqing Cardiovascular Clinical Research Center Chongqing Institute of Cardiology Chongqing P. R. China
| | - Shuo Zheng
- Department of Cardiology, Daping Hospital The Third Military Medical University Chongqing P. R. China.,Chongqing Key Laboratory for Hypertension Research Chongqing Cardiovascular Clinical Research Center Chongqing Institute of Cardiology Chongqing P. R. China
| | - Lijia Liang
- Department of Cardiology of Chongqing General Hospital Cardiovascular Research Center of Chongqing CollegeUniversity of Chinese Academy of Sciences Chongqing P. R. China
| | - Yue Chen
- Department of Cardiology, Daping Hospital The Third Military Medical University Chongqing P. R. China.,Chongqing Key Laboratory for Hypertension Research Chongqing Cardiovascular Clinical Research Center Chongqing Institute of Cardiology Chongqing P. R. China
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3
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Takei Y. Evolution of the membrane/particulate guanylyl cyclase: From physicochemical sensors to hormone receptors. Gen Comp Endocrinol 2022; 315:113797. [PMID: 33957096 DOI: 10.1016/j.ygcen.2021.113797] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/19/2021] [Accepted: 04/28/2021] [Indexed: 12/26/2022]
Abstract
Guanylyl cyclase (GC) is an enzyme that produces 3',5'-cyclic guanosine monophosphate (cGMP), one of the two canonical cyclic nucleotides used as a second messenger for intracellular signal transduction. The GCs are classified into two groups, particulate/membrane GCs (pGC) and soluble/cytosolic GCs (sGC). In relation to the endocrine system, pGCs include hormone receptors for natriuretic peptides (GC-A and GC-B) and guanylin peptides (GC-C), while sGC is a receptor for nitric oxide and carbon monoxide. Comparing the functions of pGCs in eukaryotes, it is apparent that pGCs perceive various environmental factors such as light, temperature, and various external chemical signals in addition to endocrine hormones, and transmit the information into the cell using the intracellular signaling cascade initiated by cGMP, e.g., cGMP-dependent protein kinases, cGMP-sensitive cyclic nucleotide-gated ion channels and cGMP-regulated phosphodiesterases. Among vertebrate pGCs, GC-E and GC-F are localized on retinal epithelia and are involved in modifying signal transduction from the photoreceptor, rhodopsin. GC-D and GC-G are localized in olfactory epithelia and serve as sensors at the extracellular domain for external chemical signals such as odorants and pheromones. GC-G also responds to guanylin peptides in the urine, which alters sensitivity to other chemicals. In addition, guanylin peptides that are secreted into the intestinal lumen, a pseudo-external environment, act on the GC-C on the apical membrane for regulation of epithelial transport. In this context, GC-C and GC-G appear to be in transition from exocrine pheromone receptor to endocrine hormone receptor. The pGCs also exist in various deuterostome and protostome invertebrates, and act as receptors for environmental, exocrine and endocrine factors including hormones. Tracing the evolutionary history of pGCs, it appears that pGCs first appeared as a sensor for physicochemical signals in the environment, and then evolved to function as hormone receptors. In this review, the author proposes an evolutionary history of pGCs that highlights the emerging role of the GC/cGMP system for signal transduction in hormone action.
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Affiliation(s)
- Yoshio Takei
- Laboratory of Physiology, Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan.
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4
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Prasad H, Mathew JKK, Visweswariah SS. Receptor Guanylyl Cyclase C and Cyclic GMP in Health and Disease: Perspectives and Therapeutic Opportunities. Front Endocrinol (Lausanne) 2022; 13:911459. [PMID: 35846281 PMCID: PMC9276936 DOI: 10.3389/fendo.2022.911459] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 05/26/2022] [Indexed: 11/13/2022] Open
Abstract
Receptor Guanylyl Cyclase C (GC-C) was initially characterized as an important regulator of intestinal fluid and ion homeostasis. Recent findings demonstrate that GC-C is also causally linked to intestinal inflammation, dysbiosis, and tumorigenesis. These advances have been fueled in part by identifying mutations or changes in gene expression in GC-C or its ligands, that disrupt the delicate balance of intracellular cGMP levels and are associated with a wide range of clinical phenotypes. In this review, we highlight aspects of the current knowledge of the GC-C signaling pathway in homeostasis and disease, emphasizing recent advances in the field. The review summarizes extra gastrointestinal functions for GC-C signaling, such as appetite control, energy expenditure, visceral nociception, and behavioral processes. Recent research has expanded the homeostatic role of GC-C and implicated it in regulating the ion-microbiome-immune axis, which acts as a mechanistic driver in inflammatory bowel disease. The development of transgenic and knockout mouse models allowed for in-depth studies of GC-C and its relationship to whole-animal physiology. A deeper understanding of the various aspects of GC-C biology and their relationships with pathologies such as inflammatory bowel disease, colorectal cancer, and obesity can be leveraged to devise novel therapeutics.
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Affiliation(s)
- Hari Prasad
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India
| | | | - Sandhya S. Visweswariah
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bengaluru, India
- *Correspondence: Sandhya S. Visweswariah,
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5
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Grześk G, Nowaczyk A. Current Modulation of Guanylate Cyclase Pathway Activity-Mechanism and Clinical Implications. Molecules 2021; 26:molecules26113418. [PMID: 34200064 PMCID: PMC8200204 DOI: 10.3390/molecules26113418] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/25/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023] Open
Abstract
For years, guanylate cyclase seemed to be homogenic and tissue nonspecific enzyme; however, in the last few years, in light of preclinical and clinical trials, it became an interesting target for pharmacological intervention. There are several possible options leading to an increase in cyclic guanosine monophosphate concentrations. The first one is related to the uses of analogues of natriuretic peptides. The second is related to increasing levels of natriuretic peptides by the inhibition of degradation. The third leads to an increase in cyclic guanosine monophosphate concentration by the inhibition of its degradation by the inhibition of phosphodiesterase type 5. The last option involves increasing the concentration of cyclic guanosine monophosphate by the additional direct activation of soluble guanylate cyclase. Treatment based on the modulation of guanylate cyclase function is one of the most promising technologies in pharmacology. Pharmacological intervention is stable, effective and safe. Especially interesting is the role of stimulators and activators of soluble guanylate cyclase, which are able to increase the enzymatic activity to generate cyclic guanosine monophosphate independently of nitric oxide. Moreover, most of these agents are effective in chronic treatment in heart failure patients and pulmonary hypertension, and have potential to be a first line option.
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Affiliation(s)
- Grzegorz Grześk
- Department of Cardiology and Clinical Pharmacology, Faculty of Health Sciences, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, 75 Ujejskiego St., 85-168 Bydgoszcz, Poland;
| | - Alicja Nowaczyk
- Department of Organic Chemistry, Faculty of Pharmacy, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, 2 dr. A. Jurasza St., 85-094 Bydgoszcz, Poland
- Correspondence: ; Tel.: +48-52-585-3904
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6
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Zabana Y, Lorén V, Domènech E, Aterido A, Garcia-Jaraquemada A, Julià A, Vicario M, Pedrosa E, Ferreiro M, Troya J, Lozano JJ, Sarrias MR, Cabré E, Mañosa M, Manyé J. Transcriptomic identification of TMIGD1 and its relationship with the ileal epithelial cell differentiation in Crohn's disease. Am J Physiol Gastrointest Liver Physiol 2020; 319:G109-G120. [PMID: 32508154 DOI: 10.1152/ajpgi.00027.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Crohn's disease (CD) is a complex and multifactorial illness. There are still considerable gaps in our knowledge regarding its pathophysiology. A transcriptomic approach could shed some light on little-known biological alterations of the disease. We therefore aimed to explore the ileal transcriptome to gain knowledge about CD. We performed whole transcriptome gene expression analysis on ileocecal resections from CD patients and inflammatory bowel disease-free controls, as well as on a CD-independent cohort to replicate selected results. Normalized data were hierarchically clustered, and gene ontology and the molecular network were studied. Cell cultures and molecular methods were used for further evaluations. Genome-wide expression data analysis identified a robust transmembrane immunoglobulin domain-containing 1 (TMIGD1) gene underexpression in CD tissue, which was even more marked in inflamed ileum, and which was replicated in the validation cohort. Immunofluorescence showed TMIGD1 to be located in the apical microvilli of well-differentiated enterocytes but not in intestinal crypt. This apical TMIGD1 was lower in the noninflamed tissue and almost disappeared in the inflamed mucosa of surgical resections. In vitro studies showed hypoxic-dependent TMIGD1 decreased its expression in enterocyte-like cells. The gene enrichment analysis linked TMIGD1 with cell recovery and tissue remodeling in CD settings, involving guanylate cyclase activities. Transcriptomics may be useful for finding new targets that facilitate studies of the CD pathology. This is how TMIGD1 was identified in CD patients, which was related to multiciliate ileal epithelial cell differentiation.NEW & NOTEWORTHY This is a single-center translational research study that aimed to look for key targets involved in Crohn's disease and define molecular pathways through different functional analysis strategies. With this approach, we have identified and described a novel target, the almost unknown TMIGD1 gene, which may be key in the recovery of injured mucosa involving intestinal epithelial cell differentiation.
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Affiliation(s)
- Yamile Zabana
- IBD Research Group, Germans Trias i Pujol Research Institute (IGTP), Badalona, Catalonia, Spain.,Centro de Investigación Biomédica en Red (CIBER), Madrid, Spain
| | - Violeta Lorén
- IBD Research Group, Germans Trias i Pujol Research Institute (IGTP), Badalona, Catalonia, Spain.,Centro de Investigación Biomédica en Red (CIBER), Madrid, Spain
| | - Eugeni Domènech
- IBD Research Group, Germans Trias i Pujol Research Institute (IGTP), Badalona, Catalonia, Spain.,Centro de Investigación Biomédica en Red (CIBER), Madrid, Spain.,Gastroenterology Department, Germans Trias i Pujol University Hospital, Badalona, Catalonia, Spain
| | - Adrià Aterido
- Rheumatology Research Group, Vall d'Hebron Research Institute, Barcelona, Catalonia, Spain.,Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Catalonia, Spain
| | - Arce Garcia-Jaraquemada
- IBD Research Group, Germans Trias i Pujol Research Institute (IGTP), Badalona, Catalonia, Spain
| | - Antonio Julià
- Rheumatology Research Group, Vall d'Hebron Research Institute, Barcelona, Catalonia, Spain
| | - Maria Vicario
- Centro de Investigación Biomédica en Red (CIBER), Madrid, Spain.,Laboratory of Translational Mucosal Immunology & Department of Gastroenterology, Digestive Diseases Research Unit, Vall d'Hebron Research University Hospital, Badalona, Catalonia, Spain
| | - Elisabet Pedrosa
- IBD Research Group, Germans Trias i Pujol Research Institute (IGTP), Badalona, Catalonia, Spain
| | - Miriam Ferreiro
- IBD Research Group, Germans Trias i Pujol Research Institute (IGTP), Badalona, Catalonia, Spain
| | - José Troya
- Colorectal Surgery Unit, General and Digestive Surgery Department, Germans Trias i Pujol University Hospital, Badalona, Catalonia, Spain
| | - Juan J Lozano
- Centro de Investigación Biomédica en Red (CIBER), Madrid, Spain
| | - Maria R Sarrias
- Centro de Investigación Biomédica en Red (CIBER), Madrid, Spain.,Innate Immunity Group, IGTP (AGAUR 2017-SGR-490 group), Badalona, Catalonia, Spain
| | - Eduard Cabré
- IBD Research Group, Germans Trias i Pujol Research Institute (IGTP), Badalona, Catalonia, Spain.,Centro de Investigación Biomédica en Red (CIBER), Madrid, Spain.,Gastroenterology Department, Germans Trias i Pujol University Hospital, Badalona, Catalonia, Spain
| | - Miriam Mañosa
- IBD Research Group, Germans Trias i Pujol Research Institute (IGTP), Badalona, Catalonia, Spain.,Centro de Investigación Biomédica en Red (CIBER), Madrid, Spain.,Gastroenterology Department, Germans Trias i Pujol University Hospital, Badalona, Catalonia, Spain
| | - Josep Manyé
- IBD Research Group, Germans Trias i Pujol Research Institute (IGTP), Badalona, Catalonia, Spain.,Centro de Investigación Biomédica en Red (CIBER), Madrid, Spain
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7
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Asmar A, Cramon PK, Asmar M, Simonsen L, Sorensen CM, Madsbad S, Moro C, Hartmann B, Rehfeld JF, Holst JJ, Hovind P, Jensen BL, Bülow J. Increased oral sodium chloride intake in humans amplifies selectively postprandial GLP-1 but not GIP, CCK, and gastrin in plasma. Physiol Rep 2020; 8:e14519. [PMID: 32770661 PMCID: PMC7413881 DOI: 10.14814/phy2.14519] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/03/2020] [Accepted: 07/03/2020] [Indexed: 12/24/2022] Open
Abstract
Human studies have demonstrated that physiologically relevant changes in circulating glucagon-like peptide-1 (GLP-1) elicit a rapid increase in renal sodium excretion when combined with expansion of the extracellular fluid volume. Other studies support the involvement of various gastrointestinal hormones, e.g., gastrin and cholecystokinin (CCK) in a gut-kidney axis, responsible for a rapid-acting feed-forward natriuretic mechanism. This study was designed to investigate the hypothesis that the postprandial GLP-1 plasma concentration is sensitive to the sodium content in the meal. Under fixed sodium intake for 4 days prior to each experimental day, 10 lean healthy male participants were examined twice in random order after a 12-hr fasting period. Arterial blood samples were collected at 10-20-min intervals for 140 min after 75 grams of oral glucose + 6 grams of oral sodium chloride (NaCl) load versus 75 grams of glucose alone. Twenty-four-hour baseline urinary sodium excretions were similar between study days. Arterial GLP-1 levels increased during both oral glucose loads and were significantly higher at the 40-80 min period during glucose + NaCl compared to glucose alone. The postprandial arterial responses of CCK, gastrin, and glucose-dependent insulinotropic polypeptide as well as glucose, insulin, and C-peptide did not differ between the two study days. Arterial renin, aldosterone, and natriuretic peptides levels did not change within subjects or between study days. Angiotensin II levels were significantly lower at the time GLP-1 was higher (60-80 min) during glucose + NaCl. Sodium intake in addition to a glucose load selectively amplifies the postprandial GLP-1 plasma concentration. Thus, GLP-1 may be part of an acute feed-forward mechanism for natriuresis.
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Affiliation(s)
- Ali Asmar
- Department of Clinical Physiology, Nuclear Medicine and PET, RigshospitaletUniversity of CopenhagenCopenhagenDenmark
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | - Per K. Cramon
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | - Meena Asmar
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
- Department of EndocrinologyOdense University HospitalOdenseDenmark
| | - Lene Simonsen
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | | | - Sten Madsbad
- Department of EndocrinologyHvidovre HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | - Cedric Moro
- Institut National de la Santé et de la Recherche Médicale (Inserm) UMR 1048Institute of Metabolic and Cardiovascular DiseasesPaul Sabatier UniversityToulouseFrance
| | - Bolette Hartmann
- Department of Biomedical SciencesUniversity of CopenhagenCopenhagenDenmark
- Novo Nordisk Foundation Center for Basic Metabolic ResearchUniversity of CopenhagenCopenhagenDenmark
| | - Jens F. Rehfeld
- Department of Clinical Biochemistry, RigshospitaletUniversity of CopenhagenCopenhagenDenmark
| | - Jens J. Holst
- Department of Biomedical SciencesUniversity of CopenhagenCopenhagenDenmark
- Novo Nordisk Foundation Center for Basic Metabolic ResearchUniversity of CopenhagenCopenhagenDenmark
| | - Peter Hovind
- Department of Clinical Physiology, Nuclear Medicine and PET, RigshospitaletUniversity of CopenhagenCopenhagenDenmark
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | - Boye L. Jensen
- Department of Cardiovascular and Renal ResearchUniversity of Southern DenmarkOdenseDenmark
| | - Jens Bülow
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
- Department of Biomedical SciencesUniversity of CopenhagenCopenhagenDenmark
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8
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Deciphering ion transporters, kinases and PDZ-adaptor molecules that mediate guanylate cyclase C agonist-dependent intestinal fluid loss in vivo. Biochem Pharmacol 2020; 178:114040. [DOI: 10.1016/j.bcp.2020.114040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 05/13/2020] [Indexed: 01/12/2023]
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9
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Cuevas S, Asico LD, Jose PA, Konkalmatt P. Renal Hydrogen Peroxide Production Prevents Salt-Sensitive Hypertension. J Am Heart Assoc 2020; 9:e013818. [PMID: 31902320 PMCID: PMC6988155 DOI: 10.1161/jaha.119.013818] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/05/2019] [Indexed: 02/07/2023]
Abstract
Background The regulation of sodium excretion is important in the pathogenesis of hypertension and salt sensitivity is predictive of cardiovascular events and mortality. C57Bl/6 and BALB/c mice have different blood pressure sensitivities to salt intake. High salt intake increases blood pressure in some C57Bl/6J mouse strains but not in any BALB/c mouse strain. Methods and Results We determined the cause of the difference in salt sensitivity between C57Bl/6 and BALB/c mice. Basal levels of superoxide and H2O2 were higher in renal proximal tubule cells (RPTCs) from BALB/c than C57Bl/6J mice. High salt diet increased H2O2 production in kidneys from BALB/c but C57Bl/6J mice. High sodium concentration (170 mmol/L) in the incubation medium increased H2O2 levels in BALB/c-RPTCs but not in C57Bl/6J-RPTCs. H2O2 (10 μmol/L) treatment decreased sodium transport in RPTCs from BALB/c but not C57Bl/6J mice. Overexpression of catalase in the mouse kidney predisposed BALB/c mice to salt-sensitive hypertension. Conclusions Our data show that the level of salt-induced H2O2 production negatively regulates RPTC sodium transport and determines the state of salt sensitivity in 2 strains of mice. High concentrations of antioxidants could prevent H2O2 production in renal proximal tubules, which would result in sodium retention and increased blood pressure.
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Affiliation(s)
- Santiago Cuevas
- Division of Renal Diseases & HypertensionDepartment of MedicineThe George Washington University School of Medicine and Health SciencesWashingtonDC
| | - Laureano D. Asico
- Division of Renal Diseases & HypertensionDepartment of MedicineThe George Washington University School of Medicine and Health SciencesWashingtonDC
| | - Pedro A. Jose
- Division of Renal Diseases & HypertensionDepartment of MedicineThe George Washington University School of Medicine and Health SciencesWashingtonDC
| | - Prasad Konkalmatt
- Division of Renal Diseases & HypertensionDepartment of MedicineThe George Washington University School of Medicine and Health SciencesWashingtonDC
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10
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Dugandzic A, Ratko M, Habek N. Anxiety‐like behavior in female mice changes by feeding, possible effect of guanylate cyclase C. Eur J Neurosci 2019; 52:2781-2790. [DOI: 10.1111/ejn.14607] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 10/14/2019] [Accepted: 10/22/2019] [Indexed: 01/08/2023]
Affiliation(s)
- Aleksandra Dugandzic
- Laboratory of cellular neurophysiology Croatian Institute for Brain Research School of Medicine University of Zagreb Zagreb Croatia
- Centre of Excellence for Basic, Clinical and Translational Neuroscience School of Medicine University of Zagreb Zagreb Croatia
- Department of Physiology School of Medicine University of Zagreb Zagreb Croatia
| | - Martina Ratko
- Laboratory of cellular neurophysiology Croatian Institute for Brain Research School of Medicine University of Zagreb Zagreb Croatia
- Centre of Excellence for Basic, Clinical and Translational Neuroscience School of Medicine University of Zagreb Zagreb Croatia
| | - Nikola Habek
- Laboratory of cellular neurophysiology Croatian Institute for Brain Research School of Medicine University of Zagreb Zagreb Croatia
- Centre of Excellence for Basic, Clinical and Translational Neuroscience School of Medicine University of Zagreb Zagreb Croatia
- Department of Physiology School of Medicine University of Zagreb Zagreb Croatia
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11
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Amarachintha S, Harmel-Laws E, Steinbrecher KA. Guanylate cyclase C reduces invasion of intestinal epithelial cells by bacterial pathogens. Sci Rep 2018; 8:1521. [PMID: 29367634 PMCID: PMC5784150 DOI: 10.1038/s41598-018-19868-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 12/20/2017] [Indexed: 12/24/2022] Open
Abstract
The guanylate cyclase C (GC-C) receptor regulates electrolyte and water secretion into the gut following activation by the E. coli enterotoxin STa, or by weaker endogenous agonists guanylin and uroguanylin. Our previous work has demonstrated that GC-C plays an important role in controlling initial infection as well as carrying load of non-invasive bacterial pathogens in the gut. Here, we use Salmonella enterica serovar Typhimurium to determine whether GC-C signaling is important in host defense against pathogens that actively invade enterocytes. In vitro studies indicated that GC-C signaling significantly reduces Salmonella invasion into Caco2-BBE monolayers. Relative to controls, GC-C knockout mice develop severe systemic illness following oral Salmonella infection, characterized by disrupted intestinal mucus layer, elevated cytokines and organ CFUs, and reduced animal survival. In Salmonella-infected wildtype mice, oral gavage of GC-C agonist peptide reduced host/pathogen physical interaction and diminished bacterial translocation to mesenteric lymph nodes. These studies suggest that early life susceptibility to STa-secreting enterotoxigenic E. coli may be counter-balanced by a critical role of GC-C in protecting the mucosa from non-STa producing, invasive bacterial pathogens.
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Affiliation(s)
- Surya Amarachintha
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229, USA
| | - Eleana Harmel-Laws
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229, USA
| | - Kris A Steinbrecher
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229, USA. .,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45229, USA.
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12
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Alifieris CE, Trafalis DT, Efstratopoulos AD, Alifieris EK. Evidence of the role of the vagal nerves as a monitor in the gastrointestinal-renal axis of natriuresis in human: Effects of vagotomy. Auton Neurosci 2017; 205:99-109. [PMID: 28511917 DOI: 10.1016/j.autneu.2017.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 03/27/2017] [Accepted: 05/09/2017] [Indexed: 11/30/2022]
Abstract
This study aimed to investigate the mechanism of gastrointestinal regulation of natriuresis. Sixteen subjects without (group I) and sixteen subjects with a truncal vagotomy (group II), were given a daily diet of 18mmol of sodium for 5days (D1-D5). The sodium deficit for this period was calculated for each subject and on the morning of day-6 (D6), their cumulative deficit (E) was given as 3% NaCl. In both groups the subjects were divided to receive the hypertonic saline either orally (Ior, IIor) or intravenously (Iiv, IIiv). During the period of low sodium diet when compared to group II subjects of group I (1) had a greater weight loss (p<0.005), (2) demonstrated a larger drop in pulse pressure (p<0.005), (3) achieved a positive sodium equilibrium later (D5 vs D4) and (4) developed a greater sodium deficit (p<0.005). During the two 12h periods of D6, both Ior and Iiv exhibited greater natriuresis during the first 12h period (p<0.0001) whereas both IIor and IIiv did so during the second 12h period (p<0.0001). On D6 Ior excreted the greatest percentage of E (E%; 35.63%±3.12%, p<0.0001) compared to Iiv (17.06%±1.78%), IIor (16.03%±3.54%) and IIiv (15.39%±2.77%) whereas E% was not different between the other subgroups. These results indicate that the differential natriuresis between oral and intravenous sodium loading in previously sodium deprived subjects, is due to a mechanism in which the vagal nerves play a significant role as part of neural reflex or via a natriuretic hormone.
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Affiliation(s)
- Constantinos E Alifieris
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece; Department of Surgery, Agia Olga Hospital, Athens, Greece.
| | - Dimitrios T Trafalis
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Aris D Efstratopoulos
- Third Internal Medicine and Hypertension Unit, General Hospital of Athens, National and Kapodistrian University of Athens, Athens, Greece
| | - Emmanuel K Alifieris
- Medical School, National and Kapodistrian University of Athens, Athens, Greece; Second Surgery Department, General Hospital of Chania "Agios Georgios", Chania, Greece; Second Surgery Department, Piraeus General Hospital "Agios Pandeleimon", Piraeus, Greece
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13
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The Effect of Salt Intake and Potassium Supplementation on Serum Gastrin Levels in Chinese Adults: A Randomized Trial. Nutrients 2017; 9:nu9040389. [PMID: 28420122 PMCID: PMC5409728 DOI: 10.3390/nu9040389] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/31/2017] [Accepted: 04/13/2017] [Indexed: 01/01/2023] Open
Abstract
Excess dietary salt is strongly correlated with cardiovascular disease, morbidity, and mortality. Conversely, potassium likely elicits favorable effects against cardiovascular disorders. Gastrin, which is produced by the G-cells of the stomach and duodenum, can increase renal sodium excretion and regulate blood pressure by acting on the cholecystokinin B receptor. The aim of our study was to assess the effects of altered salt and potassium supplementation on serum gastrin levels in humans. A total of 44 subjects (38–65 years old) were selected from a rural community in northern China. All subjects were sequentially maintained on a relatively low-salt diet for 7 days (3.0 g/day of NaCl), a high-salt diet for 7 days (18.0 g/day of NaCl), and then a high-salt diet supplemented with potassium for another 7 days (18.0 g/day of NaCl + 4.5 g/day of KCl). The high-salt intake significantly increased serum gastrin levels (15.3 ± 0.3 vs. 17.6 ± 0.3 pmol/L). This phenomenon was alleviated through potassium supplementation (17.6 ± 0.3 vs. 16.5 ± 0.4 pmol/L). Further analyses revealed that serum gastrin was positively correlated with 24 h urinary sodium excretion (r = 0.476, p < 0.001). By contrast, gastrin level was negatively correlated with blood pressure in all dietary interventions (r = −0.188, p = 0.031). The present study indicated that variations in dietary salt and potassium supplementation affected the serum gastrin concentrations in the Chinese subjects.
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14
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Marcolino ACS, Porto WF, Pires ÁS, Franco OL, Alencar SA. Structural impact analysis of missense SNPs present in the uroguanylin gene by long-term molecular dynamics simulations. J Theor Biol 2016; 410:9-17. [PMID: 27620667 DOI: 10.1016/j.jtbi.2016.09.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/19/2016] [Accepted: 09/08/2016] [Indexed: 12/31/2022]
Abstract
The guanylate cyclase activator 2B, also known as uroguanylin, is part of the guanylin peptide family, which includes peptides such as guanylin and lymphoguanylin. The guanylin peptides could be related to sodium absorption inhibition and water secretion induction and their dysfunction may be related to various pathologies such as chronic renal failure, congestive heart failure and nephrotic syndrome. Besides, uroguanylin point mutations have been associated with essential hypertension. However, currently there are no studies on the impact of missense SNPs on uroguanylin structure. This study applied in silico SNP impact prediction tools to evaluate the impact of uroguanylin missense SNPs and to filter those considered as convergent deleterious, which were then further analyzed through long-term molecular dynamics simulations of 1μs of duration. The simulations suggested that all missense SNPs considered as convergent deleterious caused some kind of structural change to the uroguanylin peptide. Additionally, four of these SNPs were also shown to cause modifications in peptide flexibility, possibly resulting in functional changes.
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Affiliation(s)
- Antonio C S Marcolino
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil
| | - William F Porto
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil; Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil
| | - Állan S Pires
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil; Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil
| | - Octavio L Franco
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil; Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil; S-Inova Biotech, Pós-graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil
| | - Sérgio A Alencar
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil.
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15
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Abstract
cGMP controls many cellular functions ranging from growth, viability, and differentiation to contractility, secretion, and ion transport. The mammalian genome encodes seven transmembrane guanylyl cyclases (GCs), GC-A to GC-G, which mainly modulate submembrane cGMP microdomains. These GCs share a unique topology comprising an extracellular domain, a short transmembrane region, and an intracellular COOH-terminal catalytic (cGMP synthesizing) region. GC-A mediates the endocrine effects of atrial and B-type natriuretic peptides regulating arterial blood pressure/volume and energy balance. GC-B is activated by C-type natriuretic peptide, stimulating endochondral ossification in autocrine way. GC-C mediates the paracrine effects of guanylins on intestinal ion transport and epithelial turnover. GC-E and GC-F are expressed in photoreceptor cells of the retina, and their activation by intracellular Ca(2+)-regulated proteins is essential for vision. Finally, in the rodent system two olfactorial GCs, GC-D and GC-G, are activated by low concentrations of CO2and by peptidergic (guanylins) and nonpeptidergic odorants as well as by coolness, which has implications for social behaviors. In the past years advances in human and mouse genetics as well as the development of sensitive biosensors monitoring the spatiotemporal dynamics of cGMP in living cells have provided novel relevant information about this receptor family. This increased our understanding of the mechanisms of signal transduction, regulation, and (dys)function of the membrane GCs, clarified their relevance for genetic and acquired diseases and, importantly, has revealed novel targets for therapies. The present review aims to illustrate these different features of membrane GCs and the main open questions in this field.
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Affiliation(s)
- Michaela Kuhn
- Institute of Physiology, University of Würzburg, Würzburg, Germany
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16
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Affiliation(s)
- Pedro A Jose
- From the Departments of Medicine and Physiology, The George Washington University School of Medicine and Health Sciences, Washington, DC (P.A.J.); Department of Pathology, The University of Virginia, Charlottesville (R.A.F.); Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medicine Centre, Peking Union Medical College, Beijing, P.R. China (Z.Y.); Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing Institute of Cardiology, Chongqing, P.R. China (C.Z.); and Department of Medicine, Georgetown University Medical Center, Washington, DC (G.M.E.).
| | - Robin A Felder
- From the Departments of Medicine and Physiology, The George Washington University School of Medicine and Health Sciences, Washington, DC (P.A.J.); Department of Pathology, The University of Virginia, Charlottesville (R.A.F.); Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medicine Centre, Peking Union Medical College, Beijing, P.R. China (Z.Y.); Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing Institute of Cardiology, Chongqing, P.R. China (C.Z.); and Department of Medicine, Georgetown University Medical Center, Washington, DC (G.M.E.)
| | - Zhiwei Yang
- From the Departments of Medicine and Physiology, The George Washington University School of Medicine and Health Sciences, Washington, DC (P.A.J.); Department of Pathology, The University of Virginia, Charlottesville (R.A.F.); Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medicine Centre, Peking Union Medical College, Beijing, P.R. China (Z.Y.); Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing Institute of Cardiology, Chongqing, P.R. China (C.Z.); and Department of Medicine, Georgetown University Medical Center, Washington, DC (G.M.E.)
| | - Chunyu Zeng
- From the Departments of Medicine and Physiology, The George Washington University School of Medicine and Health Sciences, Washington, DC (P.A.J.); Department of Pathology, The University of Virginia, Charlottesville (R.A.F.); Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medicine Centre, Peking Union Medical College, Beijing, P.R. China (Z.Y.); Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing Institute of Cardiology, Chongqing, P.R. China (C.Z.); and Department of Medicine, Georgetown University Medical Center, Washington, DC (G.M.E.)
| | - Gilbert M Eisner
- From the Departments of Medicine and Physiology, The George Washington University School of Medicine and Health Sciences, Washington, DC (P.A.J.); Department of Pathology, The University of Virginia, Charlottesville (R.A.F.); Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medicine Centre, Peking Union Medical College, Beijing, P.R. China (Z.Y.); Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing Institute of Cardiology, Chongqing, P.R. China (C.Z.); and Department of Medicine, Georgetown University Medical Center, Washington, DC (G.M.E.)
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17
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Ikpa PT, Sleddens HFBM, Steinbrecher KA, Peppelenbosch MP, de Jonge HR, Smits R, Bijvelds MJC. Guanylin and uroguanylin are produced by mouse intestinal epithelial cells of columnar and secretory lineage. Histochem Cell Biol 2016; 146:445-55. [PMID: 27246004 PMCID: PMC5037145 DOI: 10.1007/s00418-016-1453-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2016] [Indexed: 01/12/2023]
Abstract
Guanylin (GN) and uroguanylin (UGN), through activation of guanylyl cyclase C (GCC), serve to control intestinal fluid homeostasis. Both peptides are produced in the intestinal epithelium, but their cellular origin has not been fully charted. Using quantitative PCR and an improved in situ hybridization technique (RNAscope), we have assessed the expression of GN (Guca2a), UGN (Guca2b), and GCC (Gucy2c) in mouse intestine. In the crypts of Lieberkühn, expression of Guca2a and Guca2b was restricted to cells of secretory lineage, at the crypt's base, and to a region above, previously identified as a common origin of cellular differentiation. In this compartment, comparatively uniform levels of Guca2a and Guca2b expression were observed throughout the length of the gut. In contrast, Guca2a and Guca2b expression in the villus-surface region was more variable, and reflected the distinct, but overlapping expression pattern observed previously. Accordingly, in jejunum and ileum, Guca2a and Guca2b were abundantly expressed by enterocytes, whereas in colon only Guca2a transcript was found in the surface region. In duodenum, only low levels of Guca2b transcript were observed in columnar cells, and Guca2a expression was restricted entirely to cells of the secretory lineage. Gucy2c was shown to be expressed relatively uniformly along the rostrocaudal and crypt-villus axes and was also found in the duodenal glands. Our study reveals novel aspects of the cellular localization of the GCC signaling axis that, apart from its role in the regulation of fluid balance, link it to pH regulation, cell cycle control, and host defense.
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Affiliation(s)
- Pauline T Ikpa
- Department of Gastroenterology and Hepatology, Erasmus MC University Medical Center, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Hein F B M Sleddens
- Department of Pathology, Erasmus MC University Medical Center, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Kris A Steinbrecher
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Maikel P Peppelenbosch
- Department of Gastroenterology and Hepatology, Erasmus MC University Medical Center, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Hugo R de Jonge
- Department of Gastroenterology and Hepatology, Erasmus MC University Medical Center, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Ron Smits
- Department of Gastroenterology and Hepatology, Erasmus MC University Medical Center, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Marcel J C Bijvelds
- Department of Gastroenterology and Hepatology, Erasmus MC University Medical Center, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
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18
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Fellner RC, Moss NG, Goy MF. Dietary salt regulates uroguanylin expression and signaling activity in the kidney, but not in the intestine. Physiol Rep 2016; 4:4/9/e12782. [PMID: 27185905 PMCID: PMC4873633 DOI: 10.14814/phy2.12782] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 03/29/2016] [Indexed: 12/28/2022] Open
Abstract
The peptide uroguanylin (Ugn) is expressed at significant levels only in intestine and kidney, and is stored in both tissues primarily (perhaps exclusively) as intact prouroguanylin (proUgn). Intravascular infusion of either Ugn or proUgn evokes well-characterized natriuretic responses in rodents. Furthermore, Ugn knockout mice display hypertension and salt handling deficits, indicating that the Na(+) excretory mechanisms triggered when the peptides are infused into anesthetized animals are likely to operate under normal physiological conditions, and contribute to electrolyte homeostasis in conscious animals. Here, we provide strong corroborative evidence for this hypothesis, by demonstrating that UU gnV (the rate of urinary Ugn excretion) approximately doubled in conscious, unrestrained rats consuming a high-salt diet, and decreased by ~15% after salt restriction. These changes in UU gnV were not associated with altered plasma proUgn levels (shown here to be an accurate index of intestinal proUgn secretion). Furthermore, enteric Ugn mRNA levels were unaffected by salt intake, whereas renal Ugn mRNA levels increased sharply during periods of increased dietary salt consumption. Together, these data suggest that diet-evoked Ugn signals originate within the kidney, rather than the intestine, thus strengthening a growing body of evidence against a widely cited hypothesis that Ugn serves as the mediator of an entero-renal natriuretic signaling axis, while underscoring a likely intrarenal natriuretic role for the peptide. The data further suggest that intrarenal Ugn signaling is preferentially engaged when salt intake is elevated, and plays only a minor role when salt intake is restricted.
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Affiliation(s)
- Robert C Fellner
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Nicholas G Moss
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Michael F Goy
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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19
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Jose PA, Yang Z, Zeng C, Felder RA. The importance of the gastrorenal axis in the control of body sodium homeostasis. Exp Physiol 2016; 101:465-70. [PMID: 26854262 DOI: 10.1113/ep085286] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 02/01/2016] [Indexed: 12/27/2022]
Abstract
NEW FINDINGS What is the topic of this review? Sensing the amount of ingested sodium is one mechanism by which sodium balance is regulated. This review describes the role of gastrin in the cross-talk between the stomach and the kidney following the ingestion of sodium. What advances does it highlight? Neural mechanisms and several gut hormones, including cholecystokinin and uroguanylin, have been suggested to mediate the natriuresis after an oral sodium load. It is proposed that gastrin produced by G-cells via its receptor, cholecystokinin B receptor, interacts with renal D1 -like dopamine receptors to increase renal sodium excretion. Hypertension develops with chronically increased sodium intake when sodium that accumulates in the body can no longer be sequestered, extracellular fluid volume is expanded, and compensatory neural, hormonal and pressure-natriuresis mechanisms fail. Sensing the amount of ingested sodium, by the stomach, is one mechanism by which sodium balance is regulated. The natriuresis following the ingestion of a certain amount of sodium may be due to an enterokine, gastrin, secreted by G-cells in the stomach and duodenum and released into the circulation. Circulating gastrin levels are 10- to 20-fold higher than those for cholecystokinin. Of all the gut hormones circulating in the plasma, gastrin is the one that is reabsorbed to the greatest extent by renal tubules. Gastrin, via its receptor, the cholecystokinin type B receptor (CCKBR), is natriuretic in mammals, including humans, by inhibition of renal sodium transport. Germline deletion of gastrin (Gast) or Cckbr gene in mice causes salt-sensitive hypertension. Selective silencing of Gast in the stomach and duodenum impairs the ability to excrete an oral sodium load and also increases blood pressure. Thus, the gastrorenal axis, mediated by gastrin, can complement pronatriuretic hormones, such as dopamine, to increase sodium excretion after an oral sodium load. These studies in mice may be translatable to humans because the chromosomal loci of CCKBR and GAST are linked to human essential hypertension. Understanding the role of genes in the regulation of renal function and blood pressure may lead to the tailoring of antihypertensive treatment based on genetic make-up.
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Affiliation(s)
- Pedro A Jose
- Department of Medicine, The George Washington University School of Medicine, Washington, DC, USA.,Department of Physiology, The George Washington University School of Medicine, Washington, DC, USA
| | - Zhiwei Yang
- Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences & Comparative Medicine Centre, Peking Union Medical College, Beijing, PR China
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing Institute of Cardiology, Chongqing 400042, PR China
| | - Robin A Felder
- Department of Pathology, The University of Virginia, Charlottesville, VA, USA
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20
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Fedoseeva LA, Ryazanova MA, Ershov NI, Markel AL, Redina OE. Comparative transcriptional profiling of renal cortex in rats with inherited stress-induced arterial hypertension and normotensive Wistar Albino Glaxo rats. BMC Genet 2016; 17 Suppl 1:12. [PMID: 26821914 PMCID: PMC4895253 DOI: 10.1186/s12863-015-0306-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Background The renal function plays a leading role in long-term control of arterial pressure. The comparative analysis of renal cortex transcriptome in ISIAH rats with inherited stress-induced arterial hypertension and normotensive WAG rats was performed using RNA-Seq approach. The goal of the study was to identify the differentially expressed genes (DEGs) related to hypertension and to detect the pathways contributing to the differences in renal functions in ISIAH and WAG rats. Results The analysis revealed 716 genes differentially expressed in renal cortex of ISIAH and WAG rats, 42 of them were associated with arterial hypertension and regulation of blood pressure (BP). Several Gene Ontology (GO) terms significantly enriched with DEGs suggested the existence of the hormone dependent interstrain differences in renal cortex function. Multiple DEGs were associated with regulation of blood pressure and blood circulation, with the response to stress (including oxidative stress, hypoxia, and fluid shear stress) and its regulation. Several other processes which may contribute to hypertension development in ISIAH rats were: ion transport, regulation of calcium ion transport, homeostatic process, tissue remodeling, immune system process and regulation of immune response. KEGG analysis marked out several pathways significantly enriched with DEGs related to immune system function, to steroid hormone biosynthesis, tryptophan, glutathione, nitrogen, and drug metabolism. Conclusions The results of the study provide a basis for identification of potential biomarkers of stress-sensitive hypertension and for further investigation of the mechanisms that affect renal cortex function and hypertension development. Electronic supplementary material The online version of this article (doi:10.1186/s12863-015-0306-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Larisa A Fedoseeva
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russian Federation.
| | - Marina A Ryazanova
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russian Federation.
| | - Nikita I Ershov
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russian Federation.
| | - Arcady L Markel
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russian Federation. .,Novosibirsk State University, Novosibirsk, Russian Federation.
| | - Olga E Redina
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russian Federation.
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21
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Saraiva LR, Ahuja G, Ivandic I, Syed AS, Marioni JC, Korsching SI, Logan DW. Molecular and neuronal homology between the olfactory systems of zebrafish and mouse. Sci Rep 2015; 5:11487. [PMID: 26108469 PMCID: PMC4480006 DOI: 10.1038/srep11487] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/27/2015] [Indexed: 11/09/2022] Open
Abstract
Studies of the two major olfactory organs of rodents, the olfactory mucosa (OM) and the vomeronasal organ (VNO), unraveled the molecular basis of smell in vertebrates. However, some vertebrates lack a VNO. Here we generated and analyzed the olfactory transcriptome of the zebrafish and compared it to the olfactory transcriptomes of mouse to investigate the evolutionary and molecular relationship between single and dual olfactory systems. Our analyses revealed a high degree of molecular conservation, with orthologs of mouse olfactory cell-specific markers and all but one of their chemosensory receptor classes expressed in the single zebrafish olfactory organ. Zebrafish chemosensory receptor genes are expressed across a large dynamic range and their RNA abundance correlates positively with the number of neurons expressing that RNA. Thus we estimate the relative proportions of neuronal sub-types expressing different chemosensory receptors. Receptor repertoire size drives the absolute abundance of different classes of neurons, but we find similar underlying patterns in both species. Finally, we identified novel marker genes that characterize rare neuronal populations in both mouse and zebrafish. In sum, we find that the molecular and cellular mechanisms underpinning olfaction in teleosts and mammals are similar despite 430 million years of evolutionary divergence.
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Affiliation(s)
- Luis R Saraiva
- 1] Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton-Cambridge, CB10 1SA, United Kingdom [2] European Bioinformatics Institute (EMBL-EBI), European Molecular Biology Laboratory, Wellcome Trust Genome Campus, Hinxton-Cambridge, CB10 1SD, United Kingdom
| | - Gaurav Ahuja
- Institut für Genetik, Universität zu Köln, Cologne, 50674, Germany
| | - Ivan Ivandic
- Institut für Genetik, Universität zu Köln, Cologne, 50674, Germany
| | - Adnan S Syed
- Institut für Genetik, Universität zu Köln, Cologne, 50674, Germany
| | - John C Marioni
- European Bioinformatics Institute (EMBL-EBI), European Molecular Biology Laboratory, Wellcome Trust Genome Campus, Hinxton-Cambridge, CB10 1SD, United Kingdom
| | | | - Darren W Logan
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton-Cambridge, CB10 1SA, United Kingdom
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22
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Kang SB, Marchelletta RR, Penrose H, Docherty MJ, McCole DF. A comparison of linaclotide and lubiprostone dosing regimens on ion transport responses in human colonic mucosa. Pharmacol Res Perspect 2015; 3:e00128. [PMID: 26038704 PMCID: PMC4448989 DOI: 10.1002/prp2.128] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 01/19/2015] [Indexed: 12/17/2022] Open
Abstract
Linaclotide, a synthetic guanylyl cyclase C (GC-C) agonist, and the prostone analog, Lubiprostone, are approved to manage chronic idiopathic constipation and constipation-predominant irritable bowel syndrome. Lubiprostone also protects intestinal mucosal barrier function in ischemia. GC-C signaling regulates local fluid balance and other components of intestinal mucosal homeostasis including epithelial barrier function. The aim of this study was to compare if select dosing regimens differentially affect linaclotide and lubiprostone modulation of ion transport and barrier properties of normal human colonic mucosa. Normal sigmoid colon biopsies from healthy subjects were mounted in Ussing chambers. Tissues were treated with linaclotide, lubiprostone, or vehicle to determine effects on short-circuit current (Isc). Subsequent Isc responses to the cAMP agonist, forskolin, and the calcium agonist, carbachol, were also measured to assess if either drug caused desensitization. Barrier properties were assessed by measuring transepithelial electrical resistance. Isc responses to linaclotide and lubiprostone were significantly higher than vehicle control when administered bilaterally or to the mucosal side only. Single versus cumulative concentrations of linaclotide showed differences in efficacy while cumulative but not single dosing caused desensitization to forskolin. Lubiprostone reduced forskolin responses under all conditions. Linaclotide and lubiprostone exerted a positive effect on TER that was dependent on the dosing regimen. Linaclotide and lubiprostone increase ion transport responses across normal human colon but linaclotide displays increased sensitivity to the dosing regimen used. These findings may have implications for dosing protocols of these agents in patients with constipation.
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Affiliation(s)
- Sang Bum Kang
- Division of Gastroenterology, Department of Internal Medicine, St. Mary's Hospital, Catholic University of Korea Seoul, Korea ; Division of Gastroenterology, School of Medicine, University of California, San Diego La Jolla, California
| | - Ronald R Marchelletta
- Division of Gastroenterology, School of Medicine, University of California, San Diego La Jolla, California
| | - Harrison Penrose
- Division of Gastroenterology, School of Medicine, University of California, San Diego La Jolla, California
| | - Michael J Docherty
- Division of Gastroenterology, School of Medicine, University of California, San Diego La Jolla, California
| | - Declan F McCole
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside Riverside, California
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Begg DP, Steinbrecher KA, Mul JD, Chambers AP, Kohli R, Haller A, Cohen MB, Woods SC, Seeley RJ. Effect of guanylate cyclase-C activity on energy and glucose homeostasis. Diabetes 2014; 63:3798-804. [PMID: 24898144 PMCID: PMC4207398 DOI: 10.2337/db14-0160] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Uroguanylin is a gastrointestinal hormone primarily involved in fluid and electrolyte handling. It has recently been reported that prouroguanylin, secreted postprandially, is converted to uroguanylin in the brain and activates the receptor guanylate cyclase-C (GC-C) to reduce food intake and prevent obesity. We tested central nervous system administration of two GC-C agonists and found no significant reduction of food intake. We also carefully phenotyped mice lacking the GC-C receptor and found them to have normal body weight, adiposity, and glucose tolerance. Interestingly, uroguanylin knockout mice had a small but significant increase in body weight and adiposity that was accompanied by glucose intolerance. Our data indicate that the modest effects of uroguanylin on energy and glucose homeostasis are not mediated by central GC-C receptors.
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Affiliation(s)
- Denovan P Begg
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH School of Psychology, University of New South Wales, Sydney, New South Wales, Australia
| | - Kris A Steinbrecher
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Joram D Mul
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH
| | - Adam P Chambers
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH
| | - Rohit Kohli
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - April Haller
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH
| | - Mitchell B Cohen
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Stephen C Woods
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH
| | - Randy J Seeley
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH
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Chen Y, Asico LD, Zheng S, Villar VAM, He D, Zhou L, Zeng C, Jose PA. Gastrin and D1 dopamine receptor interact to induce natriuresis and diuresis. Hypertension 2013; 62:927-33. [PMID: 24019399 DOI: 10.1161/hypertensionaha.113.01094] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Oral NaCl produces a greater natriuresis and diuresis than the intravenous infusion of the same amount of NaCl. Gastrin is the major gastrointestinal hormone taken up by renal proximal tubule (RPT) cells. We hypothesized that renal gastrin and dopamine receptors interact to synergistically increase sodium excretion, an impaired interaction of which may be involved in the pathogenesis of hypertension. In Wistar-Kyoto rats, infusion of gastrin induced natriuresis and diuresis, which was abrogated in the presence of a gastrin (cholecystokinin B receptor [CCKBR]; CI-988) or a D1-like receptor antagonist (SCH23390). Similarly, the natriuretic and diuretic effects of fenoldopam, a D1-like receptor agonist, were blocked by SCH23390, as well as by CI-988. However, the natriuretic effects of gastrin and fenoldopam were not observed in spontaneously hypertensive rats. The gastrin/D1-like receptor interaction was also confirmed in RPT cells. In RPT cells from Wistar-Kyoto but not spontaneously hypertensive rats, stimulation of either D1-like receptor or gastrin receptor inhibited Na(+)-K(+)-ATPase activity, an effect that was blocked in the presence of SCH23390 or CI-988. In RPT cells from Wistar-Kyoto and spontaneously hypertensive rats, CCKBR and D1 receptor coimmunoprecipitated, which was increased after stimulation of either D1 receptor or CCKBR in RPT cells from Wistar-Kyoto rats; stimulation of one receptor increased the RPT cell membrane expression of the other receptor, effects that were not observed in spontaneously hypertensive rats. These data suggest that there is a synergism between CCKBR and D1-like receptors to increase sodium excretion. An aberrant interaction between the renal CCK BR and D1-like receptors (eg, D1 receptor) may play a role in the pathogenesis of hypertension.
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Affiliation(s)
- Yue Chen
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, China.
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25
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Simões-Silva L, Moreira-Rodrigues M, Quelhas-Santos J, Fernandes-Cerqueira C, Pestana M, Soares-Silva I, Sampaio-Maia B. Intestinal and renal guanylin peptides system in hypertensive obese mice. Exp Biol Med (Maywood) 2013; 238:90-7. [PMID: 23479768 DOI: 10.1258/ebm.2012.012232] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Guanylin (GN), uroguanylin (UGN) and the GC-C receptor have been associated with two endocrine axes: the salt and water homeostasis regulating enterorenal axis and the recently described appetite-regulating UGN/GC-C extraintestinal axis. The present work assessed the mRNA expression levels of GN peptides system (GPS) in a model of diet-induced obesity. Male C57BL/6J mice were submitted to either a high-fat high-simple carbohydrate diet (obese) or a normal diet (control). The renal and intestinal GN, UGN and GC-C receptor mRNA expression were evaluated by reverse transcriptase quantitative polymerase chain reaction in both groups, during normo-saline (NS) and high-saline (HS) diet. The diet-induced obesity was accompanied by glucose intolerance and insulin resistance as well as by a significant increase in blood pressure. During NS diet, obese mice presented reduced mRNA expression of GN in ileum and colon, UGN in duodenum, ileum and colon and GC-C in duodenum, jejunum, ileum and colon. This was accompanied by increased UGN mRNA expression in renal cortex. During HS diet, obese mice presented reduced mRNA expression of GN in jejunum as well as reduced mRNA expression of UGN and GC-C in duodenum, jejunum and colon. The data obtained suggest that, in a mouse model of diet-induced obesity, a down-regulation of intestinal mRNA expression of GN, UGN and its GC-C receptor is accompanied by a compensatory increase of renal UGN mRNA expression. We hypothesize that the decrease in gene expression levels of intestinal GPS may contribute to the development of hypertension and obesity during hypercaloric diet intake.
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Affiliation(s)
- Liliana Simões-Silva
- Nephrology Research and Development Unit, Faculty of Medicine, University of Porto, Alameda Prof. Hernaˆ ni Monteiro, 4200–319 Porto, Portugal
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26
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Sindic A. Current understanding of guanylin peptides actions. ISRN NEPHROLOGY 2013; 2013:813648. [PMID: 24967239 PMCID: PMC4045495 DOI: 10.5402/2013/813648] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 02/26/2013] [Indexed: 01/12/2023]
Abstract
Guanylin peptides (GPs) family includes guanylin (GN), uroguanylin (UGN), lymphoguanylin, and recently discovered renoguanylin. This growing family is proposed to be intestinal natriuretic peptides. After ingestion of a salty meal, GN and UGN are secreted into the intestinal lumen, where they inhibit sodium absorption and induce anion and water secretion. At the same conditions, those hormones stimulate renal electrolyte excretion by inducing natriuresis, kaliuresis, and diuresis and therefore prevent hypernatremia and hypervolemia after salty meals.
In the intestine, a well-known receptor for GPs is guanylate cyclase C (GC-C) whose activation increases intracellular concentration of cGMP. However, in the kidney of GC-C-deficient mice, effects of GPs are unaltered, which could be by new cGMP-independent signaling pathway (G-protein-coupled receptor). This is not unusual as atrial natriuretic peptide also activates two different types of receptors: guanylate cylcase A and clearance receptor which is also G-protein coupled receptor. Physiological role of GPs in other organs (liver, pancreas, lung, sweat glands, and male reproductive system) needs to be discovered. However, it is known that they are involved in pathological conditions like cystic fibrosis, asthma, intestinal tumors, kidney and heart failure, obesity, and metabolic syndrome.
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Affiliation(s)
- Aleksandra Sindic
- Department of Physiology, School of Medicine, University of Zagreb, Salata 3, 10000 Zagreb, Croatia
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27
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Liu T, Jose PA. Gastrin induces sodium-hydrogen exchanger 3 phosphorylation and mTOR activation via a phosphoinositide 3-kinase-/protein kinase C-dependent but AKT-independent pathway in renal proximal tubule cells derived from a normotensive male human. Endocrinology 2013; 154:865-75. [PMID: 23275470 PMCID: PMC3548178 DOI: 10.1210/en.2012-1813] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Gastrin is natriuretic, but its renal molecular targets and signal transduction pathways are not fully known. In this study, we confirmed the existence of CCKBR (a gastrin receptor) in male human renal proximal tubule cells and discovered that gastrin induced S6 phosphorylation, a downstream component of the phosphatidylinositol 3 kinase (PI3 kinase)-mammalian target of rapamycin pathway. Gastrin also increased the phosphorylation of sodium-hydrogen exchanger 3 (NHE3) at serine 552, caused its internalization, and decreased its expression at the cell surface and NHE activity. The phosphorylation of NHE3 and S6 was dependent on PI3 kinases because it was blocked by 2 different PI3-kinase inhibitors, wortmannin and LY294,002. The phosphorylation of NHE3 and S6 was not affected by the protein kinase A inhibitor H-89 but was blocked by a pan-PKC (chelerythrine) and a conventional PKC (cPKC) inhibitor (Gö6976) (10 μM) and an intracellular calcium chelator, 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, tetra(acetoxymethyl)-ester, suggesting the importance of cPKC and intracellular calcium in the gastrin signaling pathway. The cPKC involved was probably PKCα because it was phosphorylated by gastrin. The gastrin-mediated phosphorylation of NHE3, S6, and PKCα was via phospholipase C because it was blocked by a phospholipase C inhibitor, U73122 (10 μM). The phosphorylation (activation) of AKT, which is usually upstream of mammalian target of rapamycin in the classic PI3 kinase-AKT-p70S6K signaling pathway, was not affected, suggesting that the gastrin-induced phosphorylation of NHE3 and S6 is dependent on both PI3 kinase and PKCα but not AKT.
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Affiliation(s)
- Tianbing Liu
- Center for Molecular Physiology Research, Children's Research Institute, Children's National Medical Center, 111 Michigan Avenue, Washington, DC 20010, USA.
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28
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Sodium challenge does not support an acute gastrointestinal–renal natriuretic signaling axis in humans. Kidney Int 2012; 82:1313-20. [DOI: 10.1038/ki.2012.269] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Abstract
The uroguanylin system is a newly discovered endocrine/paracrine system that may have a role in the regulation of salt balance, appetite and gut health. The precursor pro-uroguanylin is predominantly synthesized in the gut, although there may be other sites of synthesis, including the kidney tubules. Products from pro-uroguanylin may mediate natriuresis following oral consumption of a salt load through both GC-C (guanylate cyclase C)-dependent and -independent mechanisms, and recent evidence suggests a role in appetite regulation. Local paracrine effects in the gut through GC-C stimulation may have tumour-suppressing actions through the regulation of cell proliferation and metabolism. Although most information on this system has been derived from knockout models, recent human studies have indicated possible roles in heart failure and renal failure. An improved understanding of the nature of its natriuretic, appetite and tumour-suppressing actions may facilitate the discovery of new therapies for heart failure, obesity and cancer prophylaxis.
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30
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Lessa LMA, Carraro-Lacroix LR, Crajoinas RO, Bezerra CN, Dariolli R, Girardi ACC, Fonteles MC, Malnic G. Mechanisms underlying the inhibitory effects of uroguanylin on NHE3 transport activity in renal proximal tubule. Am J Physiol Renal Physiol 2012; 303:F1399-408. [PMID: 22952280 DOI: 10.1152/ajprenal.00385.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We previously demonstrated that uroguanylin (UGN) significantly inhibits Na(+)/H(+) exchanger (NHE)3-mediated bicarbonate reabsorption. In the present study, we aimed to elucidate the molecular mechanisms underlying the action of UGN on NHE3 in rat renal proximal tubules and in a proximal tubule cell line (LLC-PK(1)). The in vivo studies were performed by the stationary microperfusion technique, in which we measured H(+) secretion in rat renal proximal segments, through a H(+)-sensitive microelectrode. UGN (1 μM) significantly inhibited the net of proximal bicarbonate reabsorption. The inhibitory effect of UGN was completely abolished by either the protein kinase G (PKG) inhibitor KT5823 or by the protein kinase A (PKA) inhibitor H-89. The effects of UGN in vitro were found to be similar to those obtained by microperfusion. Indeed, we observed that incubation of LLC-PK(1) cells with UGN induced an increase in the intracellular levels of cAMP and cGMP, as well as activation of both PKA and PKG. Furthermore, we found that UGN can increase the levels of NHE3 phosphorylation at the PKA consensus sites 552 and 605 in LLC-PK(1) cells. Finally, treatment of LLC-PK(1) cells with UGN reduced the amount of NHE3 at the cell surface. Overall, our data suggest that the inhibitory effect of UGN on NHE3 transport activity in proximal tubule is mediated by activation of both cGMP/PKG and cAMP/PKA signaling pathways which in turn leads to NHE3 phosphorylation and reduced NHE3 surface expression. Moreover, this study sheds light on mechanisms by which guanylin peptides are intricately involved in the maintenance of salt and water homeostasis.
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Affiliation(s)
- Lucília M A Lessa
- Department of Physiology and Biophysics, Biomedical Sciences Institute, University of São Paulo, São Paulo/SP, Brazil.
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31
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Pathological changes in tight junctions and potential applications into therapies. Drug Discov Today 2012; 17:727-32. [DOI: 10.1016/j.drudis.2012.02.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 01/15/2012] [Accepted: 02/27/2012] [Indexed: 12/30/2022]
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32
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DOCA-salt hypertension does not require the ouabain-sensitive binding site of the α2 Na,K-ATPase. Am J Hypertens 2012; 25:421-9. [PMID: 22258333 DOI: 10.1038/ajh.2011.255] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND We have shown that the ouabain-sensitive α2 Na,K-ATPase is required for adrenocorticotropic hormone (ACTH)-induced hypertension and gestational blood pressure regulation. It is therefore of interest to explore whether this binding site participates in the development of other forms of hypertension, such as deoxycorticosterone acetate (DOCA)-salt using mutant mice with altered sensitivity to ouabain. METHODS Wild-type (α1 ouabain-resistant, α2 ouabain-sensitive: α(R/R)α2(S/S)), α1-resistant, α2-resistant (α1(R/R)α2(R/R)) and α1-sensitive, α2-resistant (α1(S/S)α2(R/R)) mice were uninephrectomized and implanted with DOCA pellets. The animals were given either tap water or 1% NaCl, and blood pressure was measured before and after DOCA. RESULTS DOCA-salt-treated α1(R/R)α2(R/R) mice developed hypertension to the same extent as α1(R/R)α2(S/S) mice (wild type), and the α1(S/S)α2(R/R) mice given DOCA-salt also showed no difference from the other two genotypes. The expression of the α1 isoform was not changed by DOCA-salt treatment in either α1(R/R)α2(S/S) or α1(R/R)α2(R/R) mice. However, the α2 subunit was expressed at substantially higher levels in the hearts of α1(R/R)α2(R/R) than α1(R/R)α2(S/S) mice, regardless of treatment. Plasma levels of ouabain did not change consistently, but those of marinobufagenin were modestly higher in DOCA-salt treated mice relatively to those without salt. CONCLUSIONS The ouabain-binding site of either the α1 or α2 Na,K-ATPase subunit does not play an essential role in the development of DOCA-salt hypertension in this mouse model. These findings indicate that the underlying mechanisms of hypertension induced by DOCA-salt treatment are different from those of ACTH-induced hypertension.
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33
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Megakaryocyte development is normal in mice with targeted disruption of Tescalcin. Exp Cell Res 2012; 318:662-9. [PMID: 22285131 DOI: 10.1016/j.yexcr.2012.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 12/30/2011] [Accepted: 01/05/2012] [Indexed: 11/23/2022]
Abstract
BACKGROUND Tescalcin is an EF-hand calcium-binding protein that interacts with the Na+/H+ exchanger 1 (NHE1). Levay and Slepak recently proposed a role for tescalcin in megakaryopoiesis that was independent of NHE1 activity. Their studies using K562 and HEL cell lines, and human CD34+ hematopoietic stem cells suggested an essential role for tescalcin in megakaryocyte differentiation. OBJECTIVE To study the role of tescalcin in megakaryocyte development using a murine model of megakaryopoiesis. METHODS We generated a mouse with targeted disruption of tescalcin and investigated megakaryocyte development. RESULTS Tescalcin-deficient mice had a normal number of megakaryocytes and platelets. The morphology, polyploidization profile, and expression of Fli-1 in bone marrow-derived megakaryocytes were also normal. CONCLUSION Tescalcin does not appear to be necessary for normal megakaryocyte development.
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34
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Rozenfeld J, Tal O, Kladnitsky O, Adler L, Efrati E, Carrithers SL, Alper SL, Zelikovic I. The pendrin anion exchanger gene is transcriptionally regulated by uroguanylin: a novel enterorenal link. Am J Physiol Renal Physiol 2011; 302:F614-24. [PMID: 22129966 DOI: 10.1152/ajprenal.00189.2011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The pendrin/SLC26A4 Cl(-)/HCO(3)(-) exchanger, encoded by the PDS gene, is expressed in cortical collecting duct (CCD) non-A intercalated cells. Pendrin is essential for CCD bicarbonate secretion and is also involved in NaCl balance and blood pressure regulation. The intestinal peptide uroguanylin (UGN) is produced in response to oral salt load and can function as an "intestinal natriuretic hormone." We aimed to investigate whether UGN modulates pendrin activity and to explore the molecular mechanisms responsible for this modulation. Injection of UGN into mice resulted in decreased pendrin mRNA and protein expression in the kidney. UGN decreased endogenous pendrin mRNA levels in HEK293 cells. A 4.2-kb human PDS (hPDS) promoter sequence and consecutive 5' deletion products were cloned into luciferase reporter vectors and transiently transfected into HEK293 cells. Exposure of transfected cells to UGN decreased hPDS promoter activity. This UGN-induced effect on the hPDS promoter occurred within a 52-bp region encompassing a single heat shock element (HSE). The effect of UGN on the promoter was abolished when the HSE located between nt -1119 and -1115 was absent or was mutated. Furthermore, treatment of HEK293 cells with heat shock factor 1 (HSF1) small interfering RNA (siRNA) reversed the UGN-induced decrease in endogenous PDS mRNA level. In conclusion, pendrin-mediated Cl(-)/HCO(3)(-) exchange in the renal tubule may be regulated transcriptionally by the peptide hormone UGN. UGN exerts its inhibitory activity on the hPDS promoter likely via HSF1 action at a defined HSE site. These data define a novel signaling pathway involved in the enterorenal axis controlling electrolyte and water homeostasis.
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Affiliation(s)
- Julia Rozenfeld
- Laboratory of Developmental Nephrology, Department of Physiology and Biophysics, Haifa, Israel
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35
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Abstract
A recent report has identified uroguanylin as an endocrine signal that exerts a physiological role in energy homeostasis, adding another factor to the gut–brain axis. From a clinical point of view, several observations highlight the uroguanylin–guanylyl cyclase C pathway as a potential therapeutic target for the development of antiobesity drugs.
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36
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Potter LR. Guanylyl cyclase structure, function and regulation. Cell Signal 2011; 23:1921-6. [PMID: 21914472 DOI: 10.1016/j.cellsig.2011.09.001] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 09/02/2011] [Indexed: 02/08/2023]
Abstract
Nitric oxide, bicarbonate, natriuretic peptides (ANP, BNP and CNP), guanylins, uroguanylins and guanylyl cyclase activating proteins (GCAPs) activate a family of enzymes variously called guanyl, guanylyl or guanylate cyclases that catalyze the conversion of guanosine triphosphate to cyclic guanosine monophosphate (cGMP) and pyrophosphate. Intracellular cyclic GMP is a second messenger that modulates: platelet aggregation, neurotransmission, sexual arousal, gut peristalsis, blood pressure, long bone growth, intestinal fluid secretion, lipolysis, phototransduction, cardiac hypertrophy and oocyte maturation. This review briefly discusses the discovery of cGMP and guanylyl cyclases, then nitric oxide, nitric oxide synthase and soluble guanylyl cyclase are described in slightly greater detail. Finally, the structure, function, and regulation of the individual mammalian single membrane-spanning guanylyl cyclases GC-A, GC-B, GC-C, GC-D, GC-E, GC-F and GC-G are described in greatest detail as determined by biochemical, cell biological and gene-deletion studies.
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Affiliation(s)
- Lincoln R Potter
- Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
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37
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Valentino MA, Lin JE, Snook AE, Li P, Kim GW, Marszalowicz G, Magee MS, Hyslop T, Schulz S, Waldman SA. A uroguanylin-GUCY2C endocrine axis regulates feeding in mice. J Clin Invest 2011; 121:3578-88. [PMID: 21865642 DOI: 10.1172/jci57925] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 06/29/2011] [Indexed: 12/16/2022] Open
Abstract
Intestinal enteroendocrine cells are critical to central regulation of caloric consumption, since they activate hypothalamic circuits that decrease appetite and thereby restrict meal size by secreting hormones in response to nutrients in the gut. Although guanylyl cyclase and downstream cGMP are essential regulators of centrally regulated feeding behavior in invertebrates, the role of this primordial signaling mechanism in mammalian appetite regulation has eluded definition. In intestinal epithelial cells, guanylyl cyclase 2C (GUCY2C) is a transmembrane receptor that makes cGMP in response to the paracrine hormones guanylin and uroguanylin, which regulate epithelial cell dynamics along the crypt-villus axis. Here, we show that silencing of GUCY2C in mice disrupts satiation, resulting in hyperphagia and subsequent obesity and metabolic syndrome. This defined an appetite-regulating uroguanylin-GUCY2C endocrine axis, which we confirmed by showing that nutrient intake induces intestinal prouroguanylin secretion into the circulation. The prohormone signal is selectively decoded in the hypothalamus by proteolytic liberation of uroguanylin, inducing GUCY2C signaling and consequent activation of downstream anorexigenic pathways. Thus, evolutionary diversification of primitive guanylyl cyclase signaling pathways allows GUCY2C to coordinate endocrine regulation of central food acquisition pathways with paracrine control of intestinal homeostasis. Moreover, the uroguanylin-GUCY2C endocrine axis may provide a therapeutic target to control appetite, obesity, and metabolic syndrome.
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Affiliation(s)
- Michael A Valentino
- Department of Pharmacology and Experimental Therapeutics, Division of Clinical Pharmacology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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Fonteles MC, do Nascimento NRF. Guanylin peptide family: history, interactions with ANP, and new pharmacological perspectives. Can J Physiol Pharmacol 2011; 89:575-85. [PMID: 21815750 DOI: 10.1139/y11-050] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The guanylin family of peptides has 3 subclasses of peptides containing either 3 intramolecular disulfide bonds found in bacterial heat-stable enterotoxins (ST), or 2 disulfides observed in guanylin and uroguanylin, or a single disulfide exemplified by lymphoguanylin. These peptides bind to and activate cell-surface receptors that have intrinsic guanylate cyclase (GC) activity. These hormones are synthesized in the intestine and released both luminally and into the circulation, and are also produced within the kidney. Stimulation of renal target cells by guanylin peptides in vivo or ex vivo elicits a long-lived diuresis, natriuresis, and kaliuresis by both cGMP-dependent and independent mechanisms. Uroguanylin may act as a hormone in a novel endocrine axis linking the digestive system and kidney as well as a paracrine system intrarenally to increase sodium excretion in the postprandial period. This highly integrated and redundant mechanism allows the organism to maintain sodium balance by eliminating excess sodium in the urine. In addition, small concentrations of the atrial natriuretic peptide (ANP) can synergize with low concentrations of both guanylin or uroguanylin, which do not induce natriuresis per se, to promote significant natriuresis. Interestingly, the activation of the particulate guanylate cyclase receptors by natriuretic peptides can promote relaxation of animal and human penile erectile tissue and increase intracavernosal pressure to induce penile erection. These peptides can be prototypes for new drugs to treat erectile dysfunction, especially in patients with endothelial and nitrergic dysfunction, such as in diabetes.
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Affiliation(s)
- Manassés Claudino Fonteles
- Instituto Superior de Ciências Biomédicas (ISCB), Laboratório de Farmacologia - Universidade Estadual do Ceará (UECE), Avenida Paranjana 1700, Campus do Itaperi, CEP 60740-000, Fortaleza-CE, Brazil.
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39
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Steinbrecher KA, Harmel-Laws E, Garin-Laflam MP, Mann EA, Bezerra LD, Hogan SP, Cohen MB. Murine guanylate cyclase C regulates colonic injury and inflammation. THE JOURNAL OF IMMUNOLOGY 2011; 186:7205-14. [PMID: 21555532 DOI: 10.4049/jimmunol.1002469] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Guanylate cyclase C (GUCY2C or GC-C) and its ligands, guanylin (GUCA2A or Gn) and uroguanylin (GUCA2B or Ugn), are expressed in intestinal epithelial cells and regulate ion secretion, intestinal barrier function, and epithelial monolayer homeostasis via cGMP-dependent signaling pathways. The aim of this study was to determine whether GC-C and its ligands direct the course of intestinal inflammation. In this article, we show that dextran sodium sulfate (DSS)-induced clinical disease and histological damage to the colonic mucosa were significantly less severe in GC-C(-/-) mice and moderately reduced in Gn(-/-) animals. Relative to wild-type controls, GC-C(-/-) and Gn(-/-) mice had reduced apoptosis and increased proliferation of intestinal epithelial cells during DSS colitis. Basal and DSS-induced production of resistin-like molecule β (RELMβ) was substantially diminished in GC-C(-/-) mice. RELMβ is thought to stimulate cytokine production in macrophages in this disease model and, consistent with this, TNF-α and IFN-γ production was minimal in GC-C(-/-) animals. RELMβ and cytokine levels were similar to wild-type in Gn(-/-) mice, however. Colonic instillation of recombinant RELMβ by enema into GC-C(-/-) mice restores sensitivity to DSS-mediated mucosal injury. These findings demonstrate a novel role for GC-C signaling in facilitating mucosal wounding and inflammation, and further suggest that this may be mediated, in part, through control of RELMβ production.
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Affiliation(s)
- Kris A Steinbrecher
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA.
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Acosta RD, Cash BD. Existing and emerging therapies for irritable bowel syndrome. Expert Opin Emerg Drugs 2011; 16:389-402. [PMID: 21438740 DOI: 10.1517/14728214.2011.566214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Irritable bowel syndrome is a common disorder that is associated with a significant impact on both affected individuals and society. While the pathophysiology of irritable bowel syndrome remains unknown, knowledge regarding the normal and abnormal functions of the gut and its complex interaction with the body's nervous systems continues to shed light on the multifactorial origins of irritable bowel syndrome symptoms. This article provides an overview of the current knowledge of the therapeutic approaches to irritable bowel syndrome. AREAS COVERED A search of the online bibliographic databases MEDLINE and EMBASE was performed in order to identify all relevant articles published between 1980 and 2010. The search was enhanced with the use of a medical librarian. Bibliographies from potentially relevant articles were manually searched. EXPERT OPINION The therapeutic options for irritable bowel syndrome are rapidly evolving beyond traditional symptom-based therapies, such as fiber, antispasmodics, antidiarrheals and laxatives, and are moving toward agents with organ-specific receptor selectivity directed, in many cases, at specific gastrointestinal functions.
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Affiliation(s)
- Ruben D Acosta
- National Naval Medical Center and Walter Reed Army Medical Center, Division of Gastroenterology, 8901 Wisconsin Avenue, Bethesda, MD 20889-5000, USA
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Abstract
PURPOSE OF REVIEW Production of cyclic guanosine monophosphate (cGMP) by guanylate cyclase is of critical importance to gastrointestinal physiology. Tight regulation of cGMP concentration is necessary for proper intestinal secretion and intestinal epithelial cell proliferative and apoptotic homeostasis. This review focuses on recent work detailing the role of a subset of transmembrane guanylate cyclases in the pathophysiology of intestinal secretory and motility disorders and intestinal epithelial cell transformation. Also considered is the potential for therapeutic manipulation of intestinal guanylate cyclase/cGMP signaling for the correction of chronic constipation and gastrointestinal cancer. RECENT FINDINGS Recent work in mice and humans suggests a role for transmembrane guanylate cyclases in intestinal fluid secretion as well as hormonal enteric-renal signaling which mediates postprandial natriuresis. Transmembrane guanylate cyclases are also important in gastrointestinal transit rate and motility. Ongoing clinical trials have found that guanylate cyclase activating peptides are safe and effective in the treatment of constipation-predominant irritable bowel syndrome and chronic constipation. In addition, accumulating evidence indicates that membrane-associated guanylate cyclase receptors regulate intestinal epithelial cell homeostatic proliferation and apoptosis as well as gastrointestinal malignancy. The anticancer activity of cGMP signaling in animal studies suggests additional therapeutic applications for guanylate cyclase agonists. SUMMARY Progress toward understanding gastrointestinal transmembrane guanylate cyclase/cGMP physiology has recently accelerated due to definitive in-vitro studies and work using gene-targeted animal models and has facilitated the development of safe and effective drugs designed to regulate cGMP production in the intestine. Current work should be directed toward a detailed understanding of cGMP effector pathways and the manner in which subcellular concentrations of cGMP regulate them to influence intestinal health and disease.
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Qian X, Moss NG, Fellner RC, Taylor-Blake B, Goy MF. The rat kidney contains high levels of prouroguanylin (the uroguanylin precursor) but does not express GC-C (the enteric uroguanylin receptor). Am J Physiol Renal Physiol 2011; 300:F561-73. [PMID: 21106860 PMCID: PMC3280727 DOI: 10.1152/ajprenal.00282.2010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 11/18/2010] [Indexed: 01/13/2023] Open
Abstract
The peptide uroguanylin (Ugn) regulates enteric and renal electrolyte transport. Previous studies have shown that Ugn and its receptor GC-C (a ligand-activated guanylate cyclase) are abundant in the intestine. Less is known about Ugn and GC-C expression in the kidney. Here, we identify a 9.4-kDa polypeptide in rat kidney extracts that appears, based on its biochemical and immunological properties, to be authentic prouroguanylin (proUgn). This propeptide is relatively plentiful in the kidney (~16% of intestinal levels), whereas its mRNA is marginally present (<1% of intestinal levels), and free Ugn peptide levels are below detection limits (<0.4% of renal proUgn levels). The paucity of preproUgn-encoding mRNA and free Ugn peptide raises the possibility that the kidney might absorb intact proUgn from plasma, where the concentration of propeptide greatly exceeds that of Ugn. However, immunocytochemical analysis reveals that renal proUgn is found exclusively in distal tubular segments, sites previously shown not to accumulate radiolabeled proUgn after intravascular infusions. Thus proUgn appears to be synthesized within the kidney, but the factors that determine its abundance (rates of transcription, translation, processing, and secretion) must be balanced quite differently than in the gut. Surprisingly, we also find negligible expression of GC-C in the rat kidney, a result confirmed both by RT-PCR and by functional assays that measure Ugn-activated cGMP synthesis. Taken together, these data provide evidence for an intrarenal Ugn system that differs from the well-described intestinal system in its regulatory mechanisms and in the receptor targeted by the peptide.
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Affiliation(s)
- Xun Qian
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, NC 27599-7545, USA
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Han X, Mann E, Gilbert S, Guan Y, Steinbrecher KA, Montrose MH, Cohen MB. Loss of guanylyl cyclase C (GCC) signaling leads to dysfunctional intestinal barrier. PLoS One 2011; 6:e16139. [PMID: 21305056 PMCID: PMC3031533 DOI: 10.1371/journal.pone.0016139] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 12/11/2010] [Indexed: 12/12/2022] Open
Abstract
Background Guanylyl Cyclase C (GCC) signaling via uroguanylin (UGN) and guanylin activation is a critical mediator of intestinal fluid homeostasis, intestinal cell proliferation/apoptosis, and tumorigenesis. As a mechanism for some of these effects, we hypothesized that GCC signaling mediates regulation of intestinal barrier function. Methodology/Principal Findings Paracellular permeability of intestinal segments was assessed in wild type (WT) and GCC deficient (GCC−/−) mice with and without lipopolysaccharide (LPS) challenge, as well as in UGN deficient (UGN−/−) mice. IFNγ and myosin light chain kinase (MLCK) levels were determined by real time PCR. Expression of tight junction proteins (TJPs), phosphorylation of myosin II regulatory light chain (MLC), and STAT1 activation were examined in intestinal epithelial cells (IECs) and intestinal mucosa. The permeability of Caco-2 and HT-29 IEC monolayers, grown on Transwell filters was determined in the absence and presence of GCC RNA interference (RNAi). We found that intestinal permeability was increased in GCC−/− and UGN−/− mice compared to WT, accompanied by increased IFNγ levels, MLCK and STAT1 activation in IECs. LPS challenge promotes greater IFNγ and STAT1 activation in IECs of GCC−/− mice compared to WT mice. Claudin-2 and JAM-A expression were reduced in GCC deficient intestine; the level of phosphorylated MLC in IECs was significantly increased in GCC−/− and UGN−/− mice compared to WT. GCC knockdown induced MLC phosphorylation, increased permeability in IEC monolayers under basal conditions, and enhanced TNFα and IFNγ-induced monolayer hyperpermeability. Conclusions/Significance GCC signaling plays a protective role in the integrity of the intestinal mucosal barrier by regulating MLCK activation and TJ disassembly. GCC signaling activation may therefore represent a novel mechanism in maintaining the small bowel barrier in response to injury.
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Affiliation(s)
- Xiaonan Han
- Division of Gastroenterology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America.
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Infectious Diarrhea. PEDIATRIC GASTROINTESTINAL AND LIVER DISEASE 2011. [PMCID: PMC7151906 DOI: 10.1016/b978-1-4377-0774-8.10039-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Moss NG, Riguera DA, Fellner RC, Cazzolla C, Goy MF. Natriuretic and antikaliuretic effects of uroguanylin and prouroguanylin in the rat. Am J Physiol Renal Physiol 2010; 299:F1433-42. [PMID: 20861080 DOI: 10.1152/ajprenal.00281.2010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The peptide uroguanylin (Ugn) is stored and released as a propeptide (proUgn) by enterochromaffin cells in the intestine, and converted to Ugn and other metabolites in the renal tubules. Both proUgn and Ugn are natriuretic, although the response to proUgn is thought to depend on its conversion to Ugn within nephrons. To assess the efficiency of intrarenal conversion of proUgn to Ugn, we measured urinary Ugn excretion in rats following intravenous infusions of proUgn or Ugn. Infusion of 2 and 10 nmol proUgn/kg body wt increased plasma proUgn concentration from 2.2 ± 0.3 to 5.6 ± 1.3 pmol/ml and to 37 ± 9.6 pmol/ml, respectively. No proUgn was detected in urine before, during, or after proUgn infusions. These two proUgn infusion doses resulted in total Ugn recovery in urine of 162 ± 64 and 206 ± 39 pmol/kg body wt (9 and 2% of the infused amount, respectively). By contrast, the same molar amounts of Ugn resulted in 1,009 ± 477 and 5,352 ± 2,133 pmol/kg body wt of Ugn in urine (recoveries of ∼50%). Unexpectedly, comparisons of natriuretic dose-response curves for each peptide showed proUgn to be about five times more potent than Ugn, despite the relatively modest amount of Ugn generated from infused proUgn. In addition, both peptides were antikaliuretic at low doses, but in this case Ugn showed greater potency than proUgn. These data do not support Ugn as the primary active principle of proUgn for regulation of renal sodium excretion. Instead, an alternative peptide fragment produced from proUgn may be responsible for natriuretic activity in the kidney, whereas Ugn itself may play an antikaliuretic role.
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Affiliation(s)
- Nicholas G Moss
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Toxin mediated diarrhea in the 21 century: the pathophysiology of intestinal ion transport in the course of ETEC, V. cholerae and rotavirus infection. Toxins (Basel) 2010; 2:2132-57. [PMID: 22069677 PMCID: PMC3153279 DOI: 10.3390/toxins2082132] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 08/09/2010] [Indexed: 12/31/2022] Open
Abstract
An estimated 4 billion episodes of diarrhea occur each year. As a result, 2–3 million children and 0.5–1 million adults succumb to the consequences of this major healthcare concern. The majority of these deaths can be attributed to toxin mediated diarrhea by infectious agents, such as E. coli, V. cholerae or Rotavirus. Our understanding of the pathophysiological processes underlying these infectious diseases has notably improved over the last years. This review will focus on the cellular mechanism of action of the most common enterotoxins and the latest specific therapeutic approaches that have been developed to contain their lethal effects.
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Fonteles MC, Havt A, Prata RB, Prata PHB, Monteiro HSA, Lima AAM, Jorge ARC, Santos CF, Greenberg RN, Nascimento NRF. High-salt intake primes the rat kidney to respond to a subthreshold uroguanylin dose during ex vivo renal perfusion. ACTA ACUST UNITED AC 2009; 158:6-13. [PMID: 19632278 DOI: 10.1016/j.regpep.2009.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 07/11/2009] [Accepted: 07/17/2009] [Indexed: 01/25/2023]
Abstract
In a variety of animal models, uroguanylin causes diuresis, natriuresis and kaliuresis and is found in larger concentrations in the urine compared to controls after oral salt intake or in conditions of excess salt and fluid retention. It has been proposed that uroguanylin functions as an intestinal natriuretic hormone following intake of meals high in salt content. In the present work, we examined if 10 days of salt ingestion resulted in an enhanced response to uroguanylin in the isolated perfused rat kidney. Rats were given normal water, 1% NaCl (HS1%), or 2% NaCl (HS2%) for 10 days, at which time the right kidneys were surgically removed and perfused with a modified Krebs-Henseleit solution for 30 min. After a 30-min control period, the kidneys were perfused with a modified Krebs-Henseleit solution containing 0.06 microM uroguanylin for an additional 90 min. Compared to vehicle-matched time controls, 0.06 microM uroguanylin perfusion of kidneys from rats maintained on HS2% resulted in a significantly increased urine flow (UF; from 0.17+/-0.01 to 0.23+/-0.01, after 60 min, n=6, P<0.05), fractional Na(+) excretion (%E(Na+); from 16.6+/-0.7 to 30+/-2, after 60 min, n=6, P<0.05), fractional K(+) excretion (%E(K+); from 20.5+/-0.58 to 37.4+/-2.1, after 60 min, n=6, P<0.05), and fractional Cl(-) excretion increased from 18.16+/-0.52 to 35.2+/-2.0 at 60 min, n=6, P<0.05. With the exception of a significant increase in the %E(K)(+), no other effect was observed in the kidneys from the rats maintained on HS1%, and no significant effects were seen in those that were maintained on normal water. The effect of a higher dose (0.6 microM) of uroguanylin on urinary flow, sodium or potassium excretion was also significantly increased by 2% NaCl (HS2%) treatment (P<0.05). We also observed an expressive upregulation of the GC-C and a slight downregulation of the GC-A receptor in high-salt treated rats. These data demonstrate that prolonged salt ingestion primes the kidney to enhanced renal responses to uroguanylin.
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Affiliation(s)
- Manassés C Fonteles
- INCT-Institute of Biomedicine & Clinical Research Unit/Center for Global Health, Federal University of Ceará, Fortaleza, Ceará, Brazil.
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Garin-Laflam MP, Steinbrecher KA, Rudolph JA, Mao J, Cohen MB. Activation of guanylate cyclase C signaling pathway protects intestinal epithelial cells from acute radiation-induced apoptosis. Am J Physiol Gastrointest Liver Physiol 2009; 296:G740-9. [PMID: 19221018 PMCID: PMC2670662 DOI: 10.1152/ajpgi.90268.2008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Uroguanylin (UGN) is a peptide hormone that binds to and activates the intestinal epithelial cell (IEC) transmembrane receptor guanylate cyclase C (GC-C), which in turn increases intracellular cGMP. Gene targeting of murine UGN or GC-C results in significantly lower levels of cGMP in IECs. On the basis of effects of cGMP in nonintestinal systems, we hypothesized that loss of GC-C activation would increase intestinal epithelial apoptosis following radiation-induced injury. We first compared apoptosis from the proximal jejunum of C57BL/6 wild-type (WT) and GC-C knockout (KO) mice 3 h after they received 5 Gy of gamma-irradiation. We then investigated whether supplementation via intraperitoneal injection of 1 mM 8BrcGMP would mitigate radiation-induced apoptosis in these experimental animals. Identical experiments were performed in BALB/c UGN WT and KO mice. Apoptosis was assessed by quantitating morphological indications of cell death, terminal dUTP nick-end labeling, and cleaved caspase 3 immunohistochemistry. Both UGN KO and GC-C KO mice were more susceptible than their WT littermates in this in vivo model of apoptotic injury. Furthermore, cGMP supplementation in both GC-C and UGN KO animals ameliorated radiation-induced apoptosis. Neither WT strain demonstrated significant alteration in apoptotic susceptibility as a result of cGMP supplementation before radiation injury. These in vivo findings demonstrate increased radiosensitivity of IECs in UGN and GC-C KO mice and a role for cGMP as a primary downstream mediator of GC-C activation in the protection of these IECs from radiation-induced apoptosis.
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Affiliation(s)
- M. P. Garin-Laflam
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, and the University of Cincinnati, Cincinnati, Ohio
| | - K. A. Steinbrecher
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, and the University of Cincinnati, Cincinnati, Ohio
| | - J. A. Rudolph
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, and the University of Cincinnati, Cincinnati, Ohio
| | - J. Mao
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, and the University of Cincinnati, Cincinnati, Ohio
| | - M. B. Cohen
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, and the University of Cincinnati, Cincinnati, Ohio
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Moss NG, Riguera DA, Solinga RM, Kessler MM, Zimmer DP, Arendshorst WJ, Currie MG, Goy MF. The natriuretic peptide uroguanylin elicits physiologic actions through 2 distinct topoisomers. Hypertension 2009; 53:867-76. [PMID: 19289652 DOI: 10.1161/hypertensionaha.108.128264] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The peptide uroguanylin regulates electrolyte transport in the intestine and kidney. Human uroguanylin has 2 conformations that can be stably isolated because of their slow interconversion rate. The A isomer potently activates the guanylate cyclase C receptor found primarily in the intestine. The B isomer, by contrast, is a very weak agonist of this receptor, leading to a widely held assumption that it is physiologically irrelevant. We show here, however, that human uroguanylin B has potent natriuretic activity in the kidney. Interestingly, uroguanylin A and B both induce saluretic responses, but the activity profiles for the 2 peptides differ markedly. The uroguanylin B dose-response curve is sigmoidal with a threshold dose of approximately 10 nmol/kg of body weight, whereas uroguanylin A has a comparable threshold but a bell-shaped dose-response curve. In addition, our study indicates a unique interplay between the A and B isoforms, such that the A form at high concentrations antagonizes the natriuretic action of the B form. These data show that the kidney contains a uroguanylin receptor of which the pharmacological profile does not match that of the well-defined intestinal uroguanylin receptor (guanylate cyclase C), an observation consistent with previous studies showing that the kidney of the guanylate cyclase C knockout mouse remains responsive to uroguanylin. The results presented here also support the unconventional notion that distinct conformations of a single endocrine peptide can elicit different responses in different tissues.
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Affiliation(s)
- Nicholas G Moss
- University of North Carolina at Chapel Hill, Department of Cell and Molecular Physiology, 111 Mason Farm Rd, Chapel Hill, NC 27599, USA
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Kuhn M. Function and dysfunction of mammalian membrane guanylyl cyclase receptors: lessons from genetic mouse models and implications for human diseases. Handb Exp Pharmacol 2009:47-69. [PMID: 19089325 DOI: 10.1007/978-3-540-68964-5_4] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Besides soluble guanylyl cyclase (GC), the receptor for NO, there are seven plasma membrane forms of guanylyl cyclase (GC) receptors, enzymes that synthesize the second-messenger cyclic GMP (cGMP). All membrane GCs (GC-A to GC-G) share a basic topology, which consists of an extracellular ligand binding domain, a short transmembrane region, and an intracellular domain that contains the catalytic (GC) region. Although the presence of the extracellular domain suggests that all these enzymes function as receptors, specific ligands have been identified for only four of them (GC-A through GC-D). GC-A mediates the endocrine effects of atrial and B-type natriuretic peptides regulating arterial blood pressure and volume homeostasis and also local antihypertrophic and antifibrotic actions in the heart. GC-B, the specific receptor for C-type natriuretic peptide, has a critical role in endochondral ossification. GC-C mediates the effects of guanylin and uroguanylin on intestinal electrolyte and water transport and epithelial cell growth and differentiation. GC-E and GC-F are colocalized within the same photoreceptor cells of the retina and have an important role in phototransduction. Finally, GC-D and GC-G appear to be pseudogenes in the human. In rodents, GC-D is exclusively expressed in the olfactory neuroepithelium, with chemosensory functions. GC-G is the last member of the membrane GC form to be identified. No other mammalian transmembrane GCs are predicted on the basis of gene sequence repositories. In contrast to the other orphan receptor GCs, GC-G has a broad tissue distribution in rodents, including the lung, intestine, kidney, skeletal muscle, and sperm, raising the possibility that there is another yet to be discovered family of cGMP-generating ligands. This chapter reviews the structure and functions of membrane GCs, with special focus on the insights gained to date from genetically modified mice and the role of alterations of these ligand/receptor systems in human diseases.
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Affiliation(s)
- Michaela Kuhn
- Institut für Physiologie, Universität Würzburg, Röntgenring 9, Würzburg, 97070, Germany.
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