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Su S, Wahl A, Rugis J, Suresh V, Yule DI, Sneyd J. A mathematical model of ENaC and Slc26a6 regulation by CFTR in salivary gland ducts. Am J Physiol Gastrointest Liver Physiol 2024; 326:G555-G566. [PMID: 38349781 DOI: 10.1152/ajpgi.00168.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 01/17/2024] [Accepted: 02/06/2024] [Indexed: 02/15/2024]
Abstract
Cystic fibrosis (CF) is a genetic disease caused by the mutations of cystic fibrosis transmembrane conductance regulator (CFTR), the cystic fibrosis transmembrane conductance regulator gene. Cftr is a critical ion channel expressed in the apical membrane of mouse salivary gland striated duct cells. Although Cftr is primarily a Cl- channel, its knockout leads to higher salivary Cl- and Na+ concentrations and lower pH. Mouse experiments show that the activation of Cftr upregulates epithelial Na+ channel (ENaC) protein expression level and Slc26a6 (a 1Cl-:2[Formula: see text] exchanger of the solute carrier family) activity. Experimentally, it is difficult to predict how much the coregulation effects of CFTR contribute to the abnormal Na+, Cl-, and [Formula: see text] concentrations and pH in CF saliva. To address this question, we construct a wild-type mouse salivary gland model and simulate CFTR knockout by altering the expression levels of CFTR, ENaC, and Slc26a6. By reproducing the in vivo and ex vivo final saliva measurements from wild-type and CFTR knockout animals, we obtain computational evidence that ENaC and Slc26a6 activities are downregulated in CFTR knockout in salivary glands.NEW & NOTEWORTHY This paper describes a salivary gland mathematical model simulating the ion exchange between saliva and the salivary gland duct epithelium. The novelty lies in the implementation of CFTR regulating ENaC and Slc26a6 in a CFTR knockout gland. By reproducing the experimental saliva measurements in wild-type and CFTR knockout glands, the model shows that CFTR regulates ENaC and Slc26a6 anion exchanger in salivary glands. The method could be used to understand the various cystic fibrosis phenotypes.
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Affiliation(s)
- Shan Su
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - Amanda Wahl
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York, United States
| | - John Rugis
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - Vinod Suresh
- Auckland Biomedical Engineering Institute, University of Auckland, Auckland, New Zealand
- Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York, United States
| | - James Sneyd
- Department of Mathematics, University of Auckland, Auckland, New Zealand
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Muñoz M, Acevedo A, Ovitt CE, Luitje ME, Maruyama EO, Catalán MA. CFTR expression in human salivary gland acinar cells. Am J Physiol Cell Physiol 2024; 326:C742-C748. [PMID: 38284125 PMCID: PMC11193460 DOI: 10.1152/ajpcell.00549.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/08/2024] [Accepted: 01/20/2024] [Indexed: 01/30/2024]
Abstract
The key role of CFTR in secretory epithelia has been extensively documented. Additionally, CFTR plays a significant role in ion absorption in exocrine glands, including salivary and sweat glands. Most of the knowledge about CFTR expression comes from animal models such as the mouse or the rat, but there is limited information about CFTR expression in human tissues. In the present study, we assessed the expression of CFTR in human submandibular and parotid glands. Consistent with findings in rodent salivary glands, our immunolocalization studies show that CFTR is expressed in duct cells. However, CFTR expression in human salivary glands differs from that in rodents, as immunolocalization and single-cell RNA sequencing analysis from a previous study performed in the human parotid gland revealed the presence of CFTR protein and transcripts within a distinct cell cluster. Based on cell marker expression, this cluster corresponds to acinar cells. To obtain functional evidence supporting CFTR expression, we isolated human parotid acinar cells through collagenase digestion. Acinar cells displayed an anion conductance that was activated in response to cAMP-increasing agents and was effectively blocked by CFTRInh172, a known CFTR blocker. This study provides novel evidence of CFTR expression within acinar cells of human salivary glands. This finding challenges the established model positioning CFTR exclusively in duct cells from exocrine glands.NEW & NOTEWORTHY This study addresses the uncertainty about the impact of CFTR on human salivary gland function. We found CFTR transcripts in a subset of duct cells known as ionocytes, as well as in acinar cells. Isolated human parotid acinar cells exhibited Cl- conductance consistent with CFTR activity. This marks the first documented evidence of functional CFTR expression in human salivary gland acinar cells.
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Affiliation(s)
- Manuel Muñoz
- Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile
| | - Alejandro Acevedo
- Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile
| | - Catherine E Ovitt
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, United States
| | - Martha E Luitje
- Department of Otolaryngology, University of Rochester Medical Center, Rochester, New York, United States
| | - Eri O Maruyama
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, United States
| | - Marcelo A Catalán
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
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Wahl AM, Takano T, Su S, Warner BM, Perez P, Sneyd J, Yule DI. Structural and functional analysis of salivary intercalated duct cells reveals a secretory phenotype. J Physiol 2023; 601:4539-4556. [PMID: 37724716 PMCID: PMC10591963 DOI: 10.1113/jp285104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/30/2023] [Indexed: 09/21/2023] Open
Abstract
Currently, all salivary ducts (intercalated, striated and collecting) are assumed to function broadly in a similar manner, reclaiming ions that were secreted by the secretory acinar cells while preserving fluid volume and delivering saliva to the oral cavity. Nevertheless, there has been minimal investigation into the structural and functional differences between distinct types of salivary duct cells. Therefore, in this study, the expression profile of proteins involved in stimulus-secretion coupling, as well as the function of the intercalated duct (ID) and striated duct cells, was examined. Particular focus was placed on defining differences between distinct duct cell populations. To accomplish this, immunohistochemistry and in situ hybridization were utilized to examine the localization and expression of proteins involved in reabsorption and secretion of ions and fluid. Further, in vivo calcium imaging was employed to investigate cellular function. Based on the protein expression profile and functional data, marked differences between the IDs and striated ducts were observed. Specifically, the ID cells express proteins native to the secretory acinar cells while lacking proteins specifically expressed in the striated ducts. Further, the ID and striated duct cells display different calcium signalling characteristics, with the IDs responding to a neural stimulus in a manner similar to the acinar cells. Overall, our data suggest that the IDs have a distinct role in the secretory process, separate from the reabsorptive striated ducts. Instead, based on our evidence, the IDs express proteins found in secretory cells, generate calcium signals in a manner similar to acinar cells, and, therefore, are likely secretory cells. KEY POINTS: Current studies examining salivary intercalated duct cells are limited, with minimal documentation of the ion transport machinery and the overall role of the cells in fluid generation. Salivary intercalated duct cells are presumed to function in the same manner as other duct cells, reclaiming ions, maintaining fluid volume and delivering the final saliva to the oral cavity. Here we systematically examine the structure and function of the salivary intercalated duct cells using immunohistochemistry, in situ hybridization and by monitoring in vivo Ca2+ dynamics. Structural data revealed that the intercalated duct cells lack proteins vital for reabsorption and express proteins necessary for secretion. Ca2+ dynamics in the intercalated duct cells were consistent with those observed in secretory cells and resulted from GPCR-mediated IP3 production.
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Affiliation(s)
- Amanda M Wahl
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA
| | - Takahiro Takano
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA
| | - Shan Su
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | | | - Paola Perez
- Salivary Disorders Unit, NIDCR, Bethesda, MD, USA
| | - James Sneyd
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA
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Purushothaman AK, Nelson EJR. Role of innate immunity and systemic inflammation in cystic fibrosis disease progression. Heliyon 2023; 9:e17553. [PMID: 37449112 PMCID: PMC10336457 DOI: 10.1016/j.heliyon.2023.e17553] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 06/14/2023] [Accepted: 06/20/2023] [Indexed: 07/18/2023] Open
Abstract
Pathophysiological manifestations of cystic fibrosis (CF) result from a functional defect in the cystic fibrosis transmembrane conductance regulator (CFTR) paving way for mucus obstruction and pathogen colonization. The role of CFTR in modulating immune cell function and vascular integrity, irrespective of mucus thickening, in determining the host cell response to pathogens/allergens and causing systemic inflammation is least appreciated. Since CFTR plays a key role in the conductance of anions like Cl-, loss of CFTR function could affect various basic cellular processes, such as cellular homeostasis, lysosome acidification, and redox balance. CFTR aids in endotoxin tolerance by regulating Toll-like receptor-mediated signaling resulting in uncontrolled activation of innate immune cells. Although leukocytes of CF patients are hyperactivated, they exhibit compromised phagosome activity thus favouring the orchestration of sepsis from defective pathogen clearance. This review will emphasize the importance of innate immunity and systemic inflammatory response in the development of CF and other CFTR-associated pathologies.
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Gao J, Li A, Fujii S, Huang F, Nakatomi C, Nakamura I, Honda H, Kiyoshima T, Jimi E. p130Cas is required for androgen-dependent postnatal development regulation of submandibular glands. Sci Rep 2023; 13:5144. [PMID: 36991029 PMCID: PMC10060253 DOI: 10.1038/s41598-023-32390-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/27/2023] [Indexed: 03/31/2023] Open
Abstract
Salivary glands develop through epithelial-mesenchymal interactions and are formed through repeated branching. The Crk-associated substrate protein (p130Cas) serves as an adapter that forms a complex with various proteins via integrin and growth factor signaling, with important regulatory roles in several essential cellular processes. We found that p130Cas is expressed in ductal epithelial cells of the submandibular gland (SMG). We generated epithelial tissue-specific p130Cas-deficient (p130CasΔepi-) mice and aimed to investigate the physiological role of p130Cas in the postnatal development of salivary glands. Histological analysis showed immature development of granular convoluted tubules (GCT) of the SMG in male p130CasΔepi- mice. Immunofluorescence staining showed that nuclear-localized androgen receptors (AR) were specifically decreased in GCT cells in p130CasΔepi- mice. Furthermore, epidermal growth factor-positive secretory granules contained in GCT cells were significantly reduced in p130CasΔepi- mice with downregulated AR signaling. GCTs lacking p130Cas showed reduced numbers and size of secretory granules, disrupted subcellular localization of the cis-Golgi matrix protein GM130, and sparse endoplasmic reticulum membranes in GCT cells. These results suggest that p130Cas plays a crucial role in androgen-dependent GCT development accompanied with ER-Golgi network formation in SMG by regulating the AR signaling.
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Affiliation(s)
- Jing Gao
- Laboratory of Molecular and Cellular Biochemistry, Division of Oral Biological Sciences, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Aonan Li
- Laboratory of Molecular and Cellular Biochemistry, Division of Oral Biological Sciences, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Shinsuke Fujii
- Laboratory of Oral Pathology, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
- Dento-Craniofacial Development and Regeneration Research Center Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Fei Huang
- Laboratory of Molecular and Cellular Biochemistry, Division of Oral Biological Sciences, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Chihiro Nakatomi
- Division of Physiology, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, 803-8580, Japan
| | - Ichiro Nakamura
- Department of Rehabilitation, Yugawara Hospital, Japan Community Health Care Organization, 2-21-6 Chuo, Yugawara, Ashigara-shimo, Kanagawa, 259-0396, Japan
| | - Hiroaki Honda
- Field of Human Disease Models, Major in Advanced Life Sciences and Medicine, Institute of Laboratory Animals, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
| | - Tamotsu Kiyoshima
- Laboratory of Oral Pathology, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Eijiro Jimi
- Laboratory of Molecular and Cellular Biochemistry, Division of Oral Biological Sciences, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
- Oral Health/Brain Health/Total Health Research Center, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
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Kim YJ. Xerostomia and Its Cellular Targets. Int J Mol Sci 2023; 24:ijms24065358. [PMID: 36982432 PMCID: PMC10049126 DOI: 10.3390/ijms24065358] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/26/2023] [Accepted: 03/02/2023] [Indexed: 03/14/2023] Open
Abstract
Xerostomia, the subjective feeling of a dry mouth associated with dysfunction of the salivary glands, is mainly caused by radiation and chemotherapy, various systemic and autoimmune diseases, and drugs. As saliva plays numerous essential roles in oral and systemic health, xerostomia significantly reduces quality of life, but its prevalence is increasing. Salivation mainly depends on parasympathetic and sympathetic nerves, and the salivary glands responsible for this secretion move fluid unidirectionally through structural features such as the polarity of acinar cells. Saliva secretion is initiated by the binding of released neurotransmitters from nerves to specific G-protein-coupled receptors (GPCRs) on acinar cells. This signal induces two intracellular calcium (Ca2+) pathways (Ca2+ release from the endoplasmic reticulum and Ca2+ influx across the plasma membrane), and this increased intracellular Ca2+ concentration ([Ca2+]i) causes the translocation of the water channel aquaporin 5 (AQP5) to the apical membrane. Consequently, the GPCR-mediated increased [Ca2+]i in acinar cells promotes saliva secretion, and this saliva moves into the oral cavity through the ducts. In this review, we seek to elucidate the potential of GPCRs, the inositol 1,4,5-trisphosphate receptor (IP3R), store-operated Ca2+ entry (SOCE), and AQP5, which are essential for salivation, as cellular targets in the etiology of xerostomia.
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Affiliation(s)
- Yoon-Jung Kim
- Department of Physiology and Neuroscience, Dental Research Institute, Seoul National University School of Dentistry, Seoul 03080, Republic of Korea
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A Mathematical Model of Salivary Gland Duct Cells. Bull Math Biol 2022; 84:84. [PMID: 35799078 PMCID: PMC9262821 DOI: 10.1007/s11538-022-01041-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 06/14/2022] [Indexed: 11/18/2022]
Abstract
Saliva is produced in two stages in the salivary glands: the secretion of primary saliva by the acinus and the modification of saliva composition to final saliva by the intercalated and striated ducts. In order to understand the saliva modification process, we develop a mathematical model for the salivary gland duct. The model utilises the realistic 3D structure of the duct reconstructed from an image stack of gland tissue. Immunostaining results show that TMEM16A and aquaporin are expressed in the intercalated duct cells and that ENaC is not. Based on this, the model predicts that the intercalated duct does not absorb Na\documentclass[12pt]{minimal}
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\begin{document}$$^-$$\end{document}- like the striated duct but secretes a small amount of water instead. The input to the duct model is the time-dependent primary saliva generated by an acinar cell model. Our duct model produces final saliva output that agrees with the experimental measurements at various stimulation levels. It also shows realistic biological features such as duct cell volume, cellular concentrations and membrane potentials. Simplification of the model by omission of all detailed 3D structures of the duct makes a negligible difference to the final saliva output. This shows that saliva production is not sensitive to structural variation of the duct.
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Chibly AM, Aure MH, Patel VN, Hoffman MP. Salivary gland function, development, and regeneration. Physiol Rev 2022; 102:1495-1552. [PMID: 35343828 PMCID: PMC9126227 DOI: 10.1152/physrev.00015.2021] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 11/27/2021] [Accepted: 03/17/2022] [Indexed: 02/08/2023] Open
Abstract
Salivary glands produce and secrete saliva, which is essential for maintaining oral health and overall health. Understanding both the unique structure and physiological function of salivary glands, as well as how they are affected by disease and injury, will direct the development of therapy to repair and regenerate them. Significant recent advances, particularly in the OMICS field, increase our understanding of how salivary glands develop at the cellular, molecular, and genetic levels: the signaling pathways involved, the dynamics of progenitor cell lineages in development, homeostasis, and regeneration, and the role of the extracellular matrix microenvironment. These provide a template for cell and gene therapies as well as bioengineering approaches to repair or regenerate salivary function.
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Affiliation(s)
- Alejandro M Chibly
- Matrix and Morphogenesis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Marit H Aure
- Matrix and Morphogenesis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Vaishali N Patel
- Matrix and Morphogenesis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Matthew P Hoffman
- Matrix and Morphogenesis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
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Hayashi T, Eto K, Kadoya Y. Downregulation of ten-eleven translocation-2 triggers epithelial differentiation during organogenesis. Differentiation 2022; 125:45-53. [DOI: 10.1016/j.diff.2022.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/25/2022] [Accepted: 05/02/2022] [Indexed: 11/26/2022]
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Role of Salivary Biomarkers in Cystic Fibrosis: A Systematic Review. BIOMED RESEARCH INTERNATIONAL 2022; 2022:5818840. [PMID: 35097122 PMCID: PMC8791744 DOI: 10.1155/2022/5818840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 11/18/2022]
Abstract
Background Saliva biomarkers could be easily used as a noninvasive alternative tool for diagnosing cystic fibrosis (CF) disease. In this study, the significance of changes in salivary compositions in patients with CF was systematically reviewed. Methods An electronic search was utilized to include studies published in English, with case-control, cohort, or cross-sectional design. The evaluated salivary components were extracted and summarized. The included studies were assessed using the Strengthening the Reporting of Observational Studies in Epidemiology checklist. Results Out of 498 identified studies, nine met the eligibility criteria. Salivary electrolytes showed a substantial alteration in the CF group, especially with chloride and sodium. Total protein concentration was higher in patients with CF. However, SCN– concentration was lower in patients with CF. In addition, a reduction in the salivary flow rate and amylase levels was found in patients with CF. Conclusion Alterations in salivary biomarkers among patients with CF could be used as a promising diagnostic tool for cystic fibrosis.
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Abstract
Fluid secretion by exocrine glandular organs is essential to the survival of mammals. Each glandular unit within the body is uniquely organized to carry out its own specific functions, with failure to establish these specialized structures resulting in impaired organ function. Here, we review glandular organs in terms of shared and divergent architecture. We first describe the structural organization of the diverse glandular secretory units (the end-pieces) and their fluid transporting systems (the ducts) within the mammalian system, focusing on how tissue architecture corresponds to functional output. We then highlight how defects in development of end-piece and ductal architecture impacts secretory function. Finally, we discuss how knowledge of exocrine gland structure-function relationships can be applied to the development of new diagnostics, regenerative approaches and tissue regeneration.
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Affiliation(s)
- Sameed Khan
- Department of Obstetrics Gynecology and Reproductive Biology, Michigan State University, East Lansing, MI 48824, USA
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Sarah Fitch
- Department of Obstetrics Gynecology and Reproductive Biology, Michigan State University, East Lansing, MI 48824, USA
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Sarah Knox
- Department of Cell and Tissue Biology, University of California, San Francisco, CA 94143, USA
| | - Ripla Arora
- Department of Obstetrics Gynecology and Reproductive Biology, Michigan State University, East Lansing, MI 48824, USA
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
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Yang N, Mukaibo T, Gao X, Kurtz I, Melvin JE. Slc4a11 disruption causes duct cell loss and impairs NaCl reabsorption in female mouse submandibular glands. Physiol Rep 2019; 7:e14232. [PMID: 31833218 PMCID: PMC6908739 DOI: 10.14814/phy2.14232] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/19/2019] [Accepted: 08/20/2019] [Indexed: 12/11/2022] Open
Abstract
Slc4a11, a member of the Slc4 HCO3- transporter family, has a wide tissue distribution. In mouse salivary glands, the expression of Slc4a11 mRNA was more than eightfold greater than the other nine members of the Slc4 gene family. The Slc4a11 protein displayed a diffuse subcellular distribution in both the acinar and duct cells of mouse submandibular glands (SMG). Slc4a11 disruption induced a significant increase in the Na+ and Cl- concentrations of stimulated SMG saliva, whereas it did not affect the fluid secretion rate in response to either β-adrenergic or cholinergic receptor stimulation. Heterologous expressed mouse Slc4a11 acted as a H+ /OH- transporter that was uncoupled of Na+ or Cl- movement, and this activity was blocked by ethyl-isopropyl amiloride (EIPA) but not 4,4'-Diisothiocyanato-2,2'-stilbenedisulfonic acid (DIDS). Slc4a11 disruption revealed that Slc4a11 does not play a major role in intracellular pH regulation in mouse salivary gland cells. In contrast, NaCl reabsorption was impaired in the SMG saliva of female compared to male Slc4a11 null mice, which correlated with the loss of duct cells and a decrease in expression of the duct-cell-specific transcription factor Ascl3. Together, our results suggest that Slc4a11 expression regulates the number of ducts cells in the mouse SMG and consequently NaCl reabsorption.
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Affiliation(s)
- Ning‐Yan Yang
- Secretory Mechanisms and Dysfunctions SectionNational Institute of Dental and Craniofacial ResearchNational Institutes of HealthBethesdaMaryland
- Department of Pediatric DentistryBeijing Stomatological Hospital & School of StomatologyCapital Medical UniversityBeijingChina
| | - Taro Mukaibo
- Secretory Mechanisms and Dysfunctions SectionNational Institute of Dental and Craniofacial ResearchNational Institutes of HealthBethesdaMaryland
- Division of Oral Reconstruction and RehabilitationKyushu Dental UniversityKitakyushuFukuokaJapan
| | - Xin Gao
- Secretory Mechanisms and Dysfunctions SectionNational Institute of Dental and Craniofacial ResearchNational Institutes of HealthBethesdaMaryland
| | - Ira Kurtz
- Department of MedicineDivision of NephrologyDavid Geffen School of Medicine, and the Brain Research InstituteUniversity of CaliforniaLos AngelesCalifornia
| | - James E. Melvin
- Secretory Mechanisms and Dysfunctions SectionNational Institute of Dental and Craniofacial ResearchNational Institutes of HealthBethesdaMaryland
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Racz R, Nagy A, Rakonczay Z, Dunavari EK, Gerber G, Varga G. Defense Mechanisms Against Acid Exposure by Dental Enamel Formation, Saliva and Pancreatic Juice Production. Curr Pharm Des 2019; 24:2012-2022. [PMID: 29769002 PMCID: PMC6225347 DOI: 10.2174/1381612824666180515125654] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 04/30/2018] [Accepted: 05/08/2018] [Indexed: 12/16/2022]
Abstract
The pancreas, the salivary glands and the dental enamel producing ameloblasts have marked developmental, structural and functional similarities. One of the most striking similarities is their bicarbonate-rich secretory product, serving acid neutralization. An important difference between them is that while pancreatic juice and saliva are delivered into a lumen where they can be collected and analyzed, ameloblasts produce locally precipitating hydroxyapatite which cannot be easily studied. Interestingly, the ion and protein secretion by the pancreas, the salivary glands, and maturation ameloblasts are all two-step processes, of course with significant differences too. As they all have to defend against acid exposure by producing extremely large quantities of bicarbonate, the failure of this function leads to deteriorating consequences. The aim of the present review is to describe and characterize the defense mechanisms of the pancreas, the salivary glands and enamel-producing ameloblasts against acid exposure and to compare their functional capabilities to do this by producing bicarbonate.
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Affiliation(s)
- Robert Racz
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - Akos Nagy
- Department of Dentistry, Oral and Maxillofacial Surgery, University of Pecs, Pecs, Hungary
| | - Zoltan Rakonczay
- Department of Pathophysiology, University of Szeged, Szeged, Hungary
| | - Erika Katalin Dunavari
- Department of Dentistry, Oral and Maxillofacial Surgery, University of Pecs, Pecs, Hungary
| | - Gabor Gerber
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Gabor Varga
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
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Mukaibo T, Gao X, Yang NY, Oei MS, Nakamoto T, Melvin JE. Sexual dimorphisms in the transcriptomes of murine salivary glands. FEBS Open Bio 2019; 9:947-958. [PMID: 30998297 PMCID: PMC6487692 DOI: 10.1002/2211-5463.12625] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/05/2019] [Accepted: 03/17/2019] [Indexed: 12/25/2022] Open
Abstract
Transcriptional profiling identified 933 sexually dimorphic genes out of the 14 371 protein‐coding genes expressed in the three major murine salivary glands: parotid, sublingual, and submandibular. Most (89%) sex‐specific genes were enriched in a single gland, while only 0.5% of the sexually dimorphic genes were enriched in all glands. The sublingual gland displayed a strong male sex bias (94% of sex‐enriched genes), while a sex preference was not obvious in the parotid or submandibular glands. A subset of transcription factor genes was correlated with the expression of gland‐specific, sex‐enriched genes. Higher expression of Cftr chloride and Scnn1 sodium channels in the male submandibular correlated with greater NaCl reabsorption. In conclusion, adult salivary glands display sex‐ and gland‐specific differences in gene expression that reflect their unique functional properties.
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Affiliation(s)
- Taro Mukaibo
- Secretory Mechanisms and Dysfunctions Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.,Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Kitakyushu, Fukuoka, Japan
| | - Xin Gao
- Secretory Mechanisms and Dysfunctions Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.,Joint Institute for Food Safety and Applied Nutrition, University of Maryland, College Park, MD, USA
| | - Ning-Yan Yang
- Secretory Mechanisms and Dysfunctions Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.,Department of Pediatric Dentistry, Beijing Stomatological Hospital & School of Stomatology, Capital Medical University, Beijing, China
| | - Maria S Oei
- Secretory Mechanisms and Dysfunctions Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Tetsuji Nakamoto
- Department of Prosthodontics, Matsumoto Dental University, Shiojiri, Japan
| | - James E Melvin
- Secretory Mechanisms and Dysfunctions Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
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15
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Kondo Y, Melvin JE, Catalan MA. Physiological cAMP-elevating secretagogues differentially regulate fluid and protein secretions in mouse submandibular and sublingual glands. Am J Physiol Cell Physiol 2019; 316:C690-C697. [PMID: 30840492 DOI: 10.1152/ajpcell.00421.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The mechanisms underlying the functional differences in sympathetic and parasympathetic regulation of the major salivary glands have received little attention. The acute effects of parasympathetic muscarinic (carbachol)-dependent and combined parasympathetic-dependent plus cAMP-dependent pathways on fluid secretion rates, ion composition, and protein content were assessed using a newly developed ex vivo preparation that allows the simultaneous perfusion of the mouse submandibular (SMGs) and sublingual glands (SLGs). Our results confirm that the muscarinic-dependent pathway accounts for the bulk of salivation in SMGs and SLGs, whereas costimulation with a cAMP-increasing agent (forskolin, isoproterenol, or vasoactive intestinal peptide) did not increase the flow rate. Costimulation with carbachol plus the β-adrenergic agonist isoproterenol decreased the concentration of NaCl and produced a substantial increase in the protein and Ca2+ content of SMG but not SLG saliva, consistent with a sparse sympathetic innervation of the SLGs. On the other hand, forskolin, which bypasses receptors to increase intracellular cAMP by directly activating the enzyme adenylate cyclase, enhanced the secretion of protein and Ca2+ by both the SMGs and SLGs. In contrast, isoproterenol and vasoactive intestinal peptide specifically stimulated protein secretion in SMG and SLG salivas, respectively. In summary, cAMP-dependent signaling does not play a major role in the stimulation of fluid secretion in SMGs and SLGs, whereas each cAMP-increasing agonist behaves differently in a gland-specific manner suggesting differential expression of G protein-coupled receptors in the epithelial cells of SMGs and SLGs.
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Affiliation(s)
- Yusuke Kondo
- Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, National Institute of Dental and Craniofacial Research, National Institutes of Health , Bethesda, Maryland.,Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University , Fukuoka , Japan
| | - James E Melvin
- Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, National Institute of Dental and Craniofacial Research, National Institutes of Health , Bethesda, Maryland
| | - Marcelo A Catalan
- Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, National Institute of Dental and Craniofacial Research, National Institutes of Health , Bethesda, Maryland.,Facultad de Ciencias de la Salud, Universidad Arturo Prat , Iquique , Chile
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16
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Yokoyama T, Takemoto M, Hirakawa M, Saino T. Different immunohistochemical localization for TMEM16A and CFTR in acinar and ductal cells of rat major salivary glands and exocrine pancreas. Acta Histochem 2019; 121:50-55. [PMID: 30389171 DOI: 10.1016/j.acthis.2018.10.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/10/2018] [Accepted: 10/24/2018] [Indexed: 12/27/2022]
Abstract
We investigated the mRNA expression and immunohistochemical localization of Cl- channels, transmembrane member 16A (TMEM16A or anoctamin 1), and cystic fibrosis transmembrane conductance regulator (CFTR) in rat major salivary glands and exocrine pancreas. RT-PCR detected mRNA expression of TMEM16A and CFTR in the extracts of the parotid gland (PG), submandibular gland (SMG), sublingual gland (SLG), and pancreas. Immunoreactivity for TMEM16A was localized in the apical membrane of serous acinar and intercalated ductal cells in the PG and SMG as well as mucous acinar cells in the SLG; however, it was not detected in striated ductal cells of these tissues. Although striated ductal cells in the PG, SMG and SLG, and granular ductal cells in the SMG, were immunoreactive for CFTR in the luminal side, serous, mucous acinar, and intercalated ductal cells were not immunoreactive for CFTR in any of the major salivary glands. In the exocrine pancreas, immunoreactivity for TMEM16A was localized in the apical membrane of acinar cells, while immunoreactivity for CFTR was localized in the luminal side of intercalated ductal cells. These results suggest that different localization of TMEM16A and CFTR immunoreactivities reflects the respective functions of acinar and ductal cells in major salivary glands and exocrine pancreas.
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17
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Mukaibo T, Munemasa T, Masaki C, Cui C, Melvin J. Defective NaCl Reabsorption in Salivary Glands of Eda-Null X-LHED Mice. J Dent Res 2018; 97:1244-1251. [PMID: 29913094 PMCID: PMC6151911 DOI: 10.1177/0022034518782461] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mutations in the ectodysplasin A gene ( EDA) cause X-LHED (X-linked hypohidrotic ectodermal dysplasia), the most common human form of ectodermal dysplasia. Defective EDA signaling is linked to hypoplastic development of epithelial tissues, resulting in hypotrichosis, hypodontia, hypohidrosis, and xerostomia. The primary objective of the present study was to better understand the salivary gland dysfunction associated with ectodermal dysplasia using the analogous murine disorder. The salivary flow rate and ion composition of the 3 major salivary glands were determined in adult Eda-deficient Tabby hemizygous male (Ta/Y) and heterozygous female (Ta/X) mice. Submandibular and sublingual glands of Eda-mutant mice were smaller than wild-type littermates, while parotid gland weight was not significantly altered. Fluid secretion by the 3 major salivary glands was essentially unchanged, but the decrease in submandibular gland size was associated with a dramatic loss of ducts in Ta/Y and Ta/X mice. Reabsorption of Na+ and Cl-, previously linked in salivary glands to Scnn1 Na+ channels and Cftr Cl- channels, respectively, was markedly reduced at high flow rates in the ex vivo submandibular glands of Ta/Y mice (~60%) and, to a lesser extent, Ta/X mice (Na+ by 14%). Consistent with decreased Na+ reabsorption in Ta/Y mice, quantitative polymerase chain reaction analysis detected decreased mRNA expression for Scnn1b and Scnn1g, genes encoding the β and γ subunits, respectively. Moreover, the Na+ channel blocker amiloride significantly inhibited Na+ and Cl- reabsorption by wild-type male submandibular glands to levels comparable to those observed in Ta/Y mice. In summary, fluid secretion was intact in the salivary glands of Eda-deficient mice but displayed marked Na+ and Cl- reabsorption defects that correlated with the loss of duct cells and decreased Scnn1 Na+ channel expression. These results provide a likely mechanism for the elevated NaCl concentration observed in the saliva of affected male and female patients with X-LHED.
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Affiliation(s)
- T. Mukaibo
- Secretory Mechanisms and Dysfunctions Section,
National Institute of Dental and Craniofacial Research, National Institutes of Health,
Bethesda, MD, USA
- Department of Oral Reconstruction and
Rehabilitation, Kyushu Dental University, Kitakyushu, Japan
| | - T. Munemasa
- Secretory Mechanisms and Dysfunctions Section,
National Institute of Dental and Craniofacial Research, National Institutes of Health,
Bethesda, MD, USA
- Department of Oral Reconstruction and
Rehabilitation, Kyushu Dental University, Kitakyushu, Japan
| | - C. Masaki
- Department of Oral Reconstruction and
Rehabilitation, Kyushu Dental University, Kitakyushu, Japan
| | - C.Y. Cui
- Laboratory of Genetics and Genomics, National
Institute of Aging, National Institutes of Health, Baltimore, MD, USA
| | - J.E. Melvin
- Secretory Mechanisms and Dysfunctions Section,
National Institute of Dental and Craniofacial Research, National Institutes of Health,
Bethesda, MD, USA
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18
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Pedersen AML, Sørensen CE, Proctor GB, Carpenter GH, Ekström J. Salivary secretion in health and disease. J Oral Rehabil 2018; 45:730-746. [PMID: 29878444 DOI: 10.1111/joor.12664] [Citation(s) in RCA: 217] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2018] [Indexed: 12/16/2022]
Abstract
Saliva is a complex fluid produced by 3 pairs of major salivary glands and by hundreds of minor salivary glands. It comprises a large variety of constituents and physicochemical properties, which are important for the maintenance of oral health. Saliva not only protects the teeth and the oropharyngeal mucosa, it also facilitates articulation of speech, and is imperative for mastication and swallowing. Furthermore, saliva plays an important role in maintaining a balanced microbiota. Thus, the multiple functions provided by saliva are essential for proper protection and functioning of the body as a whole and for the general health. A large number of diseases and medications can affect salivary secretion through different mechanisms, leading to salivary gland dysfunction and associated oral problems, including xerostomia, dental caries and fungal infections. The first part of this review article provides an updated insight into our understanding of salivary gland structure, the neural regulation of salivary gland secretion, the mechanisms underlying the formation of saliva, the various functions of saliva and factors that influence salivary secretion under normal physiological conditions. The second part focuses on how various diseases and medical treatment including commonly prescribed medications and cancer therapies can affect salivary gland structure and function. We also provide a brief insight into how to diagnose salivary gland dysfunction.
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Affiliation(s)
- A M L Pedersen
- Oral Medicine, Oral Pathology & Clinical Oral Physiology, University of Copenhagen, Copenhagen, Denmark
| | - C E Sørensen
- Oral Biochemistry, Cariology & Endodontics, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - G B Proctor
- Mucosal & Salivary Biology Division, King's College London Dental Institute, London, UK
| | - G H Carpenter
- Mucosal & Salivary Biology Division, King's College London Dental Institute, London, UK
| | - J Ekström
- Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
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19
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Xu H, Ghishan FK, Kiela PR. SLC9 Gene Family: Function, Expression, and Regulation. Compr Physiol 2018; 8:555-583. [PMID: 29687889 DOI: 10.1002/cphy.c170027] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Slc9 family of Na+ /H+ exchangers (NHEs) plays a critical role in electroneutral exchange of Na+ and H+ in the mammalian intestine as well as other absorptive and secretory epithelia of digestive organs. These transport proteins contribute to the transepithelial Na+ and water absorption, intracellular pH and cellular volume regulation as well as the electrolyte, acid-base, and fluid volume homeostasis at the systemic level. They also influence the function of other membrane transport mechanisms, affect cellular proliferation and apoptosis as well as cell migration, adherence to the extracellular matrix, and tissue repair. Additionally, they modulate the extracellular milieu to facilitate other nutrient absorption and to regulate the intestinal microbial microenvironment. Na+ /H+ exchange is inhibited in selected gastrointestinal diseases, either by intrinsic factors (e.g., bile acids, inflammatory mediators) or infectious agents and associated bacterial toxins. Disrupted NHE activity may contribute not only to local and systemic electrolyte imbalance but also to the disease severity via multiple mechanisms. In this review, we describe the cation proton antiporter superfamily of Na+ /H+ exchangers with a particular emphasis on the eight SLC9A isoforms found in the digestive tract, followed by a more integrative description in their roles in each of the digestive organs. We discuss regulatory mechanisms that determine the function of Na+ /H+ exchangers as pertinent to the digestive tract, their regulation in pathological states of the digestive organs, and reciprocally, the contribution of dysregulated Na+ /H+ exchange to the disease pathogenesis and progression. © 2018 American Physiological Society. Compr Physiol 8:555-583, 2018.
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Affiliation(s)
- Hua Xu
- Department of Pediatrics, Steele Children's Research Center, University of Arizona, Tucson, Arizona, USA
| | - Fayez K Ghishan
- Department of Pediatrics, Steele Children's Research Center, University of Arizona, Tucson, Arizona, USA
| | - Pawel R Kiela
- Department of Pediatrics, Steele Children's Research Center, University of Arizona, Tucson, Arizona, USA.,Department of Immunobiology, University of Arizona, Tucson, Arizona, USA
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20
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Adthapanyawanich K, Nakata H, Iseki S. Expression and localization of phosphodiesterase 2A in the submandibular gland of mice. Arch Oral Biol 2018; 90:91-99. [PMID: 29597062 DOI: 10.1016/j.archoralbio.2018.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/16/2018] [Accepted: 03/18/2018] [Indexed: 01/04/2023]
Abstract
OBJECTIVES Phosphodiesterases comprise a superfamily of enzymes that hydrolyze and inactivate cyclic AMP (cAMP) and/or cyclic GMP (cGMP), thereby regulating cellular signaling mechanisms. We herein investigated the production of phosphodiesterase 2A (PDE2A) in the mouse submandibular gland. DESIGN The expression and localization of the mRNA and protein of PDE2A were examined in the submandibular gland of male and female mice using the reverse transcription-polymerase chain reaction, in situ hybridization, Western blotting, and immunohistochemistry. RESULTS Among the different species of phosphodiesterases examined in the mouse submandibular gland, PDE2A, which hydrolyzes cAMP and cGMP, exhibited a marked sexual difference; it was more abundantly expressed in females. The mRNA and protein signals for PDE2A were intense in all acinar and duct portions, including the striated duct, in females, whereas in males, these signals were markedly weaker in the granular convoluted duct, the counterpart of the female striated duct, than in acini and other duct portions. Furthermore, the signals for protein kinases A and G1, which are intracellular effectors of cAMP and cGMP, respectively, were markedly weaker in the male granular convoluted duct. CONCLUSIONS These results suggest that cyclic nucleotide-dependent signaling mechanisms function poorly in granular convoluted duct cells in the mouse submandibular gland.
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Affiliation(s)
- Kannika Adthapanyawanich
- Department of Histology and Cell Biology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan; Department of Anatomy, School of Medicine, Naresuan University, Pitsanulok, Thailand
| | - Hiroki Nakata
- Department of Histology and Cell Biology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Shoichi Iseki
- Department of Histology and Cell Biology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan.
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21
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Munemasa T, Mukaibo T, Kondo Y, Masaki C, Kusuda Y, Miyagi Y, Tsuka S, Hosokawa R, Nakamoto T. Salivary gland hypofunction in KK-A y type 2 diabetic mice. J Diabetes 2018; 10:18-27. [PMID: 28299899 DOI: 10.1111/1753-0407.12548] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/27/2017] [Accepted: 03/12/2017] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Hypofunction of different organs in the body is associated with diabetes, including in the oral cavity. Diabetes is often associated with xerostomia, but the underlying mechanism is not well characterized. Thus, the mechanisms underlying diabetes-induced xerostomia were investigated in this study in KK-A y mice as an experimental model of type 2 diabetes. METHODS The mechanisms involved in diabetes-induced xerostomia were investigated using the ex vivo glandular perfusion technique, histological analysis, and immunohistochemical and intracellular signaling analyses. RESULTS Ex vivo submandibular gland secretions from KK-Ay mice decreased by 30% following stimulation with 0.3 μmol/L carbachol (CCh), a cholinergic agonist. Acinar cell weight was comparable between KK-Ay and control mice, whereas duct cell weight was significantly greater in KK-Ay mice. Concentrations of Na+ and Cl- in the secreted saliva decreased significantly in KK-Ay mice, supporting the finding of increased ductal tissue in KK-Ay mice. Immunohistochemistry revealed no significant differences between KK-Ay and control mice in terms of the expression of Cl- and water channels, Na+ -K+ -2Cl- cotransporters, and membrane proteins critical for fluid secretion. Cellular signaling analysis revealed that the increase in [Ca2+ ]i in response to 0.3 μmol/L CCh was reduced by 30% in KK-Ay mice, although there was no significant difference in the thapsigargin (1.0 μmol/L)-induced increase in store-depleted calcium between KK-Ay and control mice. CONCLUSIONS These results demonstrate that submandibular fluid secretion is diminished in KK-Ay mice because of a diminished increase in [Ca2+ ]i . Duct cell weight increased in KK-Ay mice, possibly leading to increased ion reabsorption and thus decreased Na+ and Cl- concentrations in the secreted saliva.
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Affiliation(s)
- Takashi Munemasa
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Fukuoka, Japan
| | - Taro Mukaibo
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Fukuoka, Japan
| | - Yusuke Kondo
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Fukuoka, Japan
| | - Chihiro Masaki
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Fukuoka, Japan
| | - Yuichiro Kusuda
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Fukuoka, Japan
| | - Yuta Miyagi
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Fukuoka, Japan
| | - Shintaro Tsuka
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Fukuoka, Japan
| | - Ryuji Hosokawa
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Fukuoka, Japan
| | - Tetsuji Nakamoto
- Department of Prosthodontics, Matsumoto Dental University, Nagano, Japan
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22
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Fong S, Chiorini JA, Sneyd J, Suresh V. Computational modeling of epithelial fluid and ion transport in the parotid duct after transfection of human aquaporin-1. Am J Physiol Gastrointest Liver Physiol 2017; 312:G153-G163. [PMID: 27932503 PMCID: PMC5341129 DOI: 10.1152/ajpgi.00374.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/05/2016] [Accepted: 12/05/2016] [Indexed: 01/31/2023]
Abstract
UNLABELLED Previous studies have shown that localized delivery of the aquaporin-1 (AQP1) gene to the parotid duct can restore saliva flow in minipigs following irradiation-induced salivary hypofunction. The resulting flow rate and electrochemistry of secreted saliva contradicts current understanding of ductal fluid transport. We hypothesized that changes in expression of ion transport proteins have occurred following AQP1 transfection. We use a mathematical model of ion and fluid transport across the parotid duct epithelial cells to predict the expression profile of ion transporters that are consistent with the experimental measurements of saliva composition and secretion rates. Using a baseline set of parameters, the model reproduces the data for the irradiated, non-AQP1-transfected case. We propose three scenarios which may have occurred after transfection, which differ in the location of the AQP1 gene. The first scenario places AQP1 within nonsecretory cells, and requires that epithelial sodium channel (ENaC) expression is greatly reduced (1.3% of baseline), and ductal bicarbonate concentration is increased from 40.6 to 137.0 mM, to drive water secretion into the duct. The second scenario introduces the AQP1 gene into all ductal cells. The final scenario has AQP1 primarily in the proximal duct cells which secrete water under baseline conditions. We find the change in the remaining cells includes a 95.8% reduction in ENaC expression, enabling us to reproduce all experimental ionic concentrations within 9 mM. These findings provide a mechanistic basis for the observations and will guide the further development of gene transfer therapy for salivary hypofunction. NEW & NOTEWORTHY Following transfection of aquaporin into the parotid ducts of minipigs with salivary hypofunction, the resulting increase in salivary flow rates contradicts current understanding of ductal fluid transport. We show that the change in saliva electrochemistry and flow rate can be explained by changes in expression of ion transporters in the ductal cell membranes, using a mathematical model replicating a single parotid duct.
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Affiliation(s)
- Shelley Fong
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand;
| | - John A Chiorini
- 2Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland;
| | - James Sneyd
- 3Department of Mathematics, University of Auckland, Auckland, New Zealand; and
| | - Vinod Suresh
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand; ,4Department of Engineering Science, University of Auckland, Auckland, New Zealand
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23
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Shin YH, Lee SW, Kim M, Choi SY, Cong X, Yu GY, Park K. Epigenetic regulation of CFTR in salivary gland. Biochem Biophys Res Commun 2016; 481:31-37. [DOI: 10.1016/j.bbrc.2016.11.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 11/05/2016] [Indexed: 01/19/2023]
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24
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Hegyesi O, Földes A, Bori E, Németh Z, Barabás J, Steward MC, Varga G. Evidence for Active Electrolyte Transport by Two-Dimensional Monolayers of Human Salivary Epithelial Cells. Tissue Eng Part C Methods 2015. [PMID: 26200762 DOI: 10.1089/ten.tec.2014.0614] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Functional reconstruction of lost tissue by regenerative therapy of salivary glands would be of immense benefit following radiotherapy or in the treatment of Sjogren's syndrome. The purpose of this study was to develop primary cultures of human salivary gland cells as potential regenerative resources and to characterize their acinar/ductal phenotype using electrophysiological measurements of ion transport. Human salivary gland cultures were prepared either from adherent submandibular gland cells (huSMG) or from mixed adherent and nonadherent cells (PTHSG) and were cultivated in Hepato-STIM or minimum essential medium (MEM). Expression of key epithelial marker proteins was determined by quantitative reverse transcription polymerase chain reaction (RT-PCR). Transepithelial electrical resistance (TER) was monitored following seeding the cells on Transwell membranes. Transepithelial ion transport was estimated by short-circuit current (Isc) measurements in an Ussing chamber. Both huSMG and PTHSG cells showed epithelial characteristics when cultivated in Hepato-STIM, while fibroblast-like elements dominated in MEM. Compared to intact tissue, cultivation of the cells resulted in substantial decreases in AQP5 and NKCC1 expression and moderate increases in claudin-1 and ENaC expression. Both cultures achieved high TER and transepithelial electrolyte movement in Hepato-STIM, but not in MEM. The Isc was substantially reduced by basolateral Cl(-) and bicarbonate withdrawal, indicating the involvement of basolateral-to-apical anion transport, and by the blockade of apical ENaC by amiloride, indicating the involvement of apical-to-basolateral Na(+) transport. An almost complete inhibition was observed following simultaneous ENaC block and withdrawal of the two anions. Isc was enhanced by either apical adenosine triphosphate (ATP) or basolateral carbachol application, but not by forskolin, confirming the expected role of Ca(2+)-activated regulatory pathways in electrolyte secretion. Inhibition of basolateral NKCC1 by bumetanide reduced the response to ATP, indicating the active involvement of this transporter in Cl(-) secretion. In conclusion, we have demonstrated that both PTHSG and huSMG primary cultures cultivated in Hepato-STIM form two-dimensional monolayers in vitro on permeable supports and achieve active vectorial transepithelial electrolyte transport. The presence of both basolateral-to-apical anion fluxes and an apical-to-basolateral Na(+) flux indicates both acinar and ductal characteristics. With further refinement, this model should provide a firm basis for new interventions to correct salivary gland dysfunction.
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Affiliation(s)
- Orsolya Hegyesi
- 1 Department of Oral Biology, Semmelweis University , Budapest, Hungary
| | - Anna Földes
- 1 Department of Oral Biology, Semmelweis University , Budapest, Hungary
| | - Erzsébet Bori
- 1 Department of Oral Biology, Semmelweis University , Budapest, Hungary
| | - Zsolt Németh
- 2 Department of Oro-Maxillofacial Surgery and Stomatology, Semmelweis University , Budapest, Hungary
| | - József Barabás
- 2 Department of Oro-Maxillofacial Surgery and Stomatology, Semmelweis University , Budapest, Hungary
| | - Martin C Steward
- 3 Faculty of Life Sciences, University of Manchester , Manchester, United Kingdom
| | - Gábor Varga
- 1 Department of Oral Biology, Semmelweis University , Budapest, Hungary
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25
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Zinn VZ, Khatri A, Mednieks MI, Hand AR. Localization of cystic fibrosis transmembrane conductance regulator signaling complexes in human salivary gland striated duct cells. Eur J Oral Sci 2015; 123:140-8. [PMID: 25903037 DOI: 10.1111/eos.12184] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2015] [Indexed: 02/03/2023]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP-dependent protein kinase (PKA)-regulated Cl(-) channel, crucial for epithelial cell regulation of salt and water transport. Previous studies showed that ezrin, an actin binding and A-kinase anchoring protein (AKAP), facilitates association of PKA with CFTR. We used immunohistochemistry and immunogold transmission electron microscopy to localize CFTR, ezrin, and PKA type II regulatory (RII) and catalytic (C) subunits in striated duct cells of human parotid and submandibular glands. Immunohistochemistry localized the four proteins mainly to the apical membrane and the apical cytoplasm of striated duct cells. In acinar cells, ezrin localized to the luminal membrane, and PKA RII subunits were present in secretory granules, as previously described. Immunogold labeling showed that CFTR and PKA RII and C subunits were localized to the luminal membrane and associated with apical granules and vesicles of striated duct cells. Ezrin was present along the luminal membrane, on microvilli and along the junctional complexes between cells. Double labeling showed specific protein associations with apical granules and vesicles and along the luminal membrane. Ezrin, CFTR, and PKA RII and C subunits are co-localized in striated duct cells, suggesting the presence of signaling complexes that serve to regulate CFTR activity.
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Affiliation(s)
- Vina Z Zinn
- University of Connecticut School of Dental Medicine, Farmington, CT, USA
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26
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ENaC in the Rabbit Lacrimal Gland and its Changes During Sjögren Syndrome and Pregnancy. Eye Contact Lens 2015; 41:297-303. [PMID: 25828511 DOI: 10.1097/icl.0000000000000123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Epithelial sodium channel (ENaC) plays a critical role in the control of Na(+) balance and the development and progression of exocrine gland pathologic condition. The aim of the present study was to investigate the presence of ENaC in the rabbit lacrimal gland (LG) and its potential changes during induced autoimmune dacryoadenitis (IAD) and pregnancy. METHODS Total messenger RNA (mRNA) of α, β, and γ subunits was extracted from whole LG, acinar cells, and ductal cells by laser capture microdissection (LCM) for real-time reverse-transcriptase polymerase chain reaction. Lacrimal glands were processed for Western blot and immunofluorescence. RESULTS Messenger RNA for both α and γ was expressed in whole LG lysates, whereas β was undetectable. In rabbits with IAD, the levels of mRNA for α and γ were 20.9% and 58.9% lower (P<0.05), whereas no significant changes were observed in term-pregnant rabbits (P=0.152). However, we were unable to detect mRNA of any subunit in LCM specimens of ductal cells because of their low levels. Western blot demonstrated bands for both α (90 kDa) and γ (85 kDa) but β was undetectable. In rabbits with IAD, densitometry analysis showed that expression of α decreased 22%, whereas γ decreased 26% (P<0.05). In pregnant rabbits, however, α expression was 31% lower, whereas γ expression was 34% lower (P<0.05). From immunofluorescence studies, all subunits were present in ductal cells, whereas virtually no immunoreactivity was detected in acini. No noticeable changes of their distribution pattern and intensity were found in rabbits with IAD or during pregnancy. CONCLUSIONS The present study demonstrated the presence of ENaC in the rabbit LG and its alterations in IAD and pregnancy, suggesting that ENaC may contribute to the pathogenesis of altered LG secretion and ocular surface symptoms in these animals.
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Peña-Münzenmayer G, Catalán MA, Kondo Y, Jaramillo Y, Liu F, Shull GE, Melvin JE. Ae4 (Slc4a9) Anion Exchanger Drives Cl- Uptake-dependent Fluid Secretion by Mouse Submandibular Gland Acinar Cells. J Biol Chem 2015; 290:10677-88. [PMID: 25745107 DOI: 10.1074/jbc.m114.612895] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Indexed: 12/22/2022] Open
Abstract
Transcellular Cl(-) movement across acinar cells is the rate-limiting step for salivary gland fluid secretion. Basolateral Nkcc1 Na(+)-K(+)-2Cl(-) cotransporters play a critical role in fluid secretion by promoting the intracellular accumulation of Cl(-) above its equilibrium potential. However, salivation is only partially abolished in the absence of Nkcc1 cotransporter activity, suggesting that another Cl(-) uptake pathway concentrates Cl(-) ions in acinar cells. To identify alternative molecular mechanisms, we studied mice lacking Ae2 and Ae4 Cl(-)/HCO3 (-) exchangers. We found that salivation stimulated by muscarinic and β-adrenergic receptor agonists was normal in the submandibular glands of Ae2(-/-) mice. In contrast, saliva secretion was reduced by 35% in Ae4(-/-) mice. The decrease in salivation was not related to loss of Na(+)-K(+)-2Cl(-) cotransporter or Na(+)/H(+) exchanger activity in Ae4(-/-) mice but correlated with reduced Cl(-) uptake during β-adrenergic receptor activation of cAMP signaling. Direct measurements of Cl(-)/HCO3 (-) exchanger activity revealed that HCO3 (-)-dependent Cl(-) uptake was reduced in the acinar cells of Ae2(-/-) and Ae4(-/-) mice. Moreover, Cl(-)/HCO3 (-) exchanger activity was nearly abolished in double Ae4/Ae2 knock-out mice, suggesting that most of the Cl(-)/HCO3 (-) exchanger activity in submandibular acinar cells depends on Ae2 and Ae4 expression. In conclusion, both Ae2 and Ae4 anion exchangers are functionally expressed in submandibular acinar cells; however, only Ae4 expression appears to be important for cAMP-dependent regulation of fluid secretion.
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Affiliation(s)
- Gaspar Peña-Münzenmayer
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Marcelo A Catalán
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Yusuke Kondo
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, the Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Kitakyushu, Fukuoka, Japan
| | - Yasna Jaramillo
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Frances Liu
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Gary E Shull
- the Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, and
| | - James E Melvin
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892,
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Hand AR, Elder KO, Norris RP. Redistribution of Gαs in mouse salivary glands following β-adrenergic stimulation. Arch Oral Biol 2015; 60:715-23. [PMID: 25748393 DOI: 10.1016/j.archoralbio.2015.01.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 10/15/2014] [Accepted: 01/20/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Signalling via β-adrenergic receptors activates heterotrimeric G-proteins, which dissociate into α and βγ subunits. In salivary glands, the α subunit of Gs stimulates adenylate cyclase, increasing cyclic AMP levels and promoting exocytosis. The goals of this study were to determine Gαs localization in salivary glands and whether it undergoes redistribution upon activation. METHODS Mouse parotid and submandibular (SMG) glands were fixed with paraformaldehyde and prepared for immunofluorescence labelling with anti-Gαs. RESULTS In unstimulated parotid and SMG acinar cells, Gαs was localized mainly to basolateral membranes. Some parotid acinar cells also exhibited cytoplasmic fluorescence. Isoproterenol (IPR) stimulation resulted in decreased membrane fluorescence and increased cytoplasmic fluorescence, which appeared relatively uniform by 30 min. Beginning about 2 h after IPR, cytoplasmic fluorescence decreased and membrane fluorescence increased, approaching unstimulated levels in SMG acini by 4 h. Some parotid acini exhibited cytoplasmic fluorescence up to 8 h after IPR. The IPR-induced redistribution of Gαs was prevented (SMG) or reduced (parotid) by prior injection of propranolol. Striated duct cells of unstimulated mice exhibited general cytoplasmic fluorescence, which was unchanged after IPR. CONCLUSIONS Gαs is localized to basolateral membranes of unstimulated salivary acinar cells. Activation of Gαs causes its release from the cell membrane and movement into the cytoplasm. Reassociation of Gαs with the membrane begins about 2 h after stimulation in the SMG, but complete reassociation takes several hours in the parotid gland. The presence of Gαs in striated duct cells suggests a role in signal transduction of secretion and/or electrolyte transport processes.
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Affiliation(s)
- Arthur R Hand
- Department of Craniofacial Sciences, University of Connecticut Health Center, Farmington, CT, USA; Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA.
| | - Kareen O Elder
- Department of Craniofacial Sciences, University of Connecticut Health Center, Farmington, CT, USA
| | - Rachael P Norris
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
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A fluid secretion pathway unmasked by acinar-specific Tmem16A gene ablation in the adult mouse salivary gland. Proc Natl Acad Sci U S A 2015; 112:2263-8. [PMID: 25646474 DOI: 10.1073/pnas.1415739112] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Activation of an apical Ca(2+)-activated Cl(-) channel (CaCC) triggers the secretion of saliva. It was previously demonstrated that CaCC-mediated Cl(-) current and Cl(-) efflux are absent in the acinar cells of systemic Tmem16A (Tmem16A Cl(-) channel) null mice, but salivation was not assessed in fully developed glands because Tmem16A null mice die within a few days after birth. To test the role of Tmem16A in adult salivary glands, we generated conditional knockout mice lacking Tmem16A in acinar cells (Tmem16A(-/-)). Ca(2+)-dependent salivation was abolished in Tmem16A(-/-) mice, demonstrating that Tmem16A is obligatory for Ca(2+)-mediated fluid secretion. However, the amount of saliva secreted by Tmem16A(-/-) mice in response to the β-adrenergic receptor agonist isoproterenol (IPR) was comparable to that seen in controls, indicating that Tmem16A does not significantly contribute to cAMP-induced secretion. Furthermore, IPR-stimulated secretion was unaffected in mice lacking Cftr (Cftr(∆F508/∆F508)) or ClC-2 (Clcn2(-/-)) Cl(-) channels. The time course for activation of IPR-stimulated fluid secretion closely correlated with that of the IPR-induced cell volume increase, suggesting that acinar swelling may activate a volume-sensitive Cl(-) channel. Indeed, Cl(-) channel blockers abolished fluid secretion, indicating that Cl(-) channel activity is critical for IPR-stimulated secretion. These data suggest that β-adrenergic-induced, cAMP-dependent fluid secretion involves a volume-regulated anion channel. In summary, our results using acinar-specific Tmem16A(-/-) mice identify Tmem16A as the Cl(-) channel essential for muscarinic, Ca(2+)-dependent fluid secretion in adult mouse salivary glands.
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Bronckers ALJJ, Lyaruu DM, Guo J, Bijvelds MJC, Bervoets TJM, Zandieh-Doulabi B, Medina JF, Li Z, Zhang Y, DenBesten PK. Composition of mineralizing incisor enamel in cystic fibrosis transmembrane conductance regulator-deficient mice. Eur J Oral Sci 2014; 123:9-16. [PMID: 25557910 DOI: 10.1111/eos.12163] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2014] [Indexed: 12/25/2022]
Abstract
Formation of crystals in the enamel space releases protons that need to be buffered to sustain mineral accretion. We hypothesized that apical cystic fibrosis transmembrane conductance regulator (CFTR) in maturation ameloblasts transduces chloride into forming enamel as a critical step to secrete bicarbonates. We tested this by determining the calcium, chloride, and fluoride levels in developing enamel of Cftr-null mice by quantitative electron probe microanalysis. Maturation-stage enamel from Cftr-null mice contained less chloride and calcium than did wild-type enamel, was more acidic when stained with pH dyes ex vivo, and formed no fluorescent modulation bands after in vivo injection of the mice with calcein. To acidify the enamel further we exposed Cftr-null mice to fluoride in drinking water to stimulate proton release during formation of hypermineralized lines. In Cftr-deficient mice, fluoride further lowered enamel calcium without further reducing chloride levels. The data support the view that apical CFTR in maturation ameloblasts tranduces chloride into developing enamel as part of the machinery to buffer protons released during mineral accretion.
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Affiliation(s)
- Antonius L J J Bronckers
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute, University of Amsterdam and VU University Amsterdam, Amsterdam, the Netherlands
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Multiscale modelling of saliva secretion. Math Biosci 2014; 257:69-79. [PMID: 25014770 DOI: 10.1016/j.mbs.2014.06.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 06/18/2014] [Accepted: 06/26/2014] [Indexed: 01/28/2023]
Abstract
We review a multiscale model of saliva secretion, describing in brief how the model is constructed and what we have so far learned from it. The model begins at the level of inositol trisphosphate receptors (IPR), and proceeds through the cellular level (with a model of acinar cell calcium dynamics) to the multicellular level (with a model of the acinus), finally to a model of a saliva production unit that includes an acinus and associated duct. The model at the level of the entire salivary gland is not yet completed. Particular results from the model so far include (i) the importance of modal behaviour of IPR, (ii) the relative unimportance of Ca(2+) oscillation frequency as a controller of saliva secretion, (iii) the need for the periodic Ca(2+) waves to be as fast as possible in order to maximise water transport, (iv) the presence of functional K(+) channels in the apical membrane increases saliva secretion, (v) the relative unimportance of acinar spatial structure for isotonic water transport, (vi) the prediction that duct cells are highly depolarised, (vii) the prediction that the secondary saliva takes at least 1mm (from the acinus) to reach ionic equilibrium. We end with a brief discussion of future directions for the model, both in construction and in the study of scientific questions.
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Sengar AS, Agarwal A, Singh MK. Cystic fibrosis: need for mass deployable screening methods. Appl Biochem Biotechnol 2014; 174:1127-36. [PMID: 24880895 DOI: 10.1007/s12010-014-0991-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 05/19/2014] [Indexed: 11/26/2022]
Abstract
Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CFTR is a member of the adenosine triphosphate (ATP)-binding cassette superfamily of proteins and it functions as a chloride channel. CFTR largely controls the working of epithelial cells of the airways, the gastrointestinal tract, exocrine glands, and genitourinary system. Cystic fibrosis is responsible for severe chronic pulmonary disorders in children. Other maladies in the spectrum of this life-limiting disorder include nasal polyposis, pansinusitis, rectal prolapse, pancreatitis, cholelithiasis, insulin-dependent hyperglycemia, and cirrhosis. This review summarizes the recent state of art in the field of cystic fibrosis diagnostic methods with the help of CF literature published so far and proposes new research domains in the field of cystic fibrosis diagnosis.
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Affiliation(s)
- Aditya Singh Sengar
- Department of Electronics and Communication, The LNM Institute of Information Technology, Jaipur, 302031, India,
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Korbmacher JP, Michel C, Neubauer D, Thompson K, Mizaikoff B, Frick M, Dietl P, Wittekindt OH. Amiloride-sensitive fluid resorption in NCI-H441 lung epithelia depends on an apical Cl(-) conductance. Physiol Rep 2014; 2:e00201. [PMID: 24744880 PMCID: PMC3967684 DOI: 10.1002/phy2.201] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 12/12/2013] [Accepted: 12/21/2013] [Indexed: 01/12/2023] Open
Abstract
Proper apical airway surface hydration is essential to maintain lung function. This hydration depends on well‐balanced water resorption and secretion. The mechanisms involved in resorption are still a matter of debate, especially as the measurement of transepithelial water transport remains challenging. In this study, we combined classical short circuit current (ISC) measurements with a novel D2O dilution method to correlate ion and water transport in order to reveal basic transport mechanisms in lung epithelia. D2O dilution method enabled precise analysis of water resorption with an unprecedented resolution. NCI‐H441 cells cultured at an air–liquid interface resorbed water at a rate of 1.5 ± 0.4 μL/(h cm2). Water resorption and ISC were reduced by almost 80% in the presence of the bulk Cl− channel inhibitor 5‐nitro‐2‐(3‐phenylpropylamino)benzoic acid (NPPB) or amiloride, a specific inhibitor of epithelial sodium channel (ENaC). However, water resorption and ISC were only moderately affected by forskolin or cystic fibrosis transmembrane regulator (CFTR) channel inhibitors (CFTRinh‐172 and glybenclamide). In line with previous studies, we demonstrate that water resorption depends on ENaC, and CFTR channels have only a minor but probably modulating effect on water resorption. However, the major ENaC‐mediated water resorption depends on an apical non‐CFTR Cl− conductance. We investigated water transport across lung epithelia, using a novel D2O dilution method in combination with Ussing chamber experiments. Our results revealed that CFTR channels have a minor modulating effect on water resorption. The major ENaC‐mediated resorption depends on non‐CFTR channels.
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Affiliation(s)
- Jonas P Korbmacher
- Institute of General Physiology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Christiane Michel
- Institute of General Physiology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Daniel Neubauer
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Kristin Thompson
- Institute of General Physiology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Boris Mizaikoff
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Manfred Frick
- Institute of General Physiology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Paul Dietl
- Institute of General Physiology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Oliver H Wittekindt
- Institute of General Physiology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
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Li Y, Liu C, Hou W, Li Y, Ma J, Lin K, Situ Z, Xiong L, Li S, Yao L. Retrograde ductal administration of the adenovirus-mediated NDRG2 gene leads to improved sialaden hypofunction in estrogen-deficient rats. Mol Ther 2013; 22:908-18. [PMID: 24343104 DOI: 10.1038/mt.2013.286] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 12/09/2013] [Indexed: 01/27/2023] Open
Abstract
One of the most common oral manifestations of menopause is xerostomia. Oral dryness can profoundly affect quality of life and interfere with basic daily functions, such as chewing, deglutition, and speaking. Although the feeling of oral dryness can be ameliorated after estrogen supplementation, the side effects of estrogen greatly restrict its application. We previously found that N-myc downstream-regulated gene 2 (NDRG2) is involved in estrogen-mediated ion and fluid transport in a cell-based model. In the present study, we used an ovariectomized rat model to mimic xerostomia in menopausal women and constructed two adenovirus vectors bearing NDRG2 to validate their therapeutic potential. Ovariectomized rats exhibited severe sialaden hypofunction, including decreased saliva secretion and ion reabsorption as well as increased water intake. Immunohistochemistry revealed that the expression of NDRG2 and Na(+) reabsorption-related Na(+)/K(+)-ATPase and epithelial sodium channels (EnaC) decreased in ovariectomized rat salivary glands. We further showed that the localized delivery of NDRG2 improved the dysfunction of Na(+) and Cl(-) reabsorption. In addition, the saliva flow rate and water drinking recovered to normal. This study elucidates the mechanism of estrogen deficiency-mediated xerostomia or sialaden hypofunction and provides a promising strategy for therapeutic intervention.
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Affiliation(s)
- Yan Li
- 1] Department of Biochemistry and Molecular Biology, The State Key Laboratory of Cancer Biology, The Fourth Military Medical University, Xi'an, China [2] Department of Oral Biology, Stomatology School, The Fourth Military Medical University, Xi'an, China [3] Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Changhao Liu
- Department of Biochemistry and Molecular Biology, The State Key Laboratory of Cancer Biology, The Fourth Military Medical University, Xi'an, China
| | - Wugang Hou
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Yang Li
- Institute of Medical Information, China Academy of Medical Sciences, Beijing, China
| | - Ji Ma
- Department of Biochemistry and Molecular Biology, The State Key Laboratory of Cancer Biology, The Fourth Military Medical University, Xi'an, China
| | - Kaifeng Lin
- Department of Biochemistry and Molecular Biology, The State Key Laboratory of Cancer Biology, The Fourth Military Medical University, Xi'an, China
| | - Zhenqiang Situ
- Department of Oral Biology, Stomatology School, The Fourth Military Medical University, Xi'an, China
| | - Lize Xiong
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Shaoqing Li
- Department of Oral Biology, Stomatology School, The Fourth Military Medical University, Xi'an, China
| | - Libo Yao
- Department of Biochemistry and Molecular Biology, The State Key Laboratory of Cancer Biology, The Fourth Military Medical University, Xi'an, China
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Hong JH, Park S, Shcheynikov N, Muallem S. Mechanism and synergism in epithelial fluid and electrolyte secretion. Pflugers Arch 2013; 466:1487-99. [PMID: 24240699 DOI: 10.1007/s00424-013-1390-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 10/16/2013] [Accepted: 10/17/2013] [Indexed: 01/04/2023]
Abstract
A central function of epithelia is the control of the volume and electrolyte composition of bodily fluids through vectorial transport of electrolytes and the obligatory H2O. In exocrine glands, fluid and electrolyte secretion is carried out by both acinar and duct cells, with the portion of fluid secreted by each cell type varying among glands. All acinar cells secrete isotonic, plasma-like fluid, while the duct determines the final electrolyte composition of the fluid by absorbing most of the Cl(-) and secreting HCO3 (-). The key transporters mediating acinar fluid and electrolyte secretion are the basolateral Na(+)/K(+) /2Cl(-) cotransporter, the luminal Ca(2+)-activated Cl(-) channel ANO1 and basolateral and luminal Ca(2+)-activated K(+) channels. Ductal fluid and HCO3 (-) secretion are mediated by the basolateral membrane Na(+)-HCO3 (-) cotransporter NBCe1-B and the luminal membrane Cl(-)/HCO3 (-) exchanger slc26a6 and the Cl(-) channel CFTR. The function of the transporters is regulated by multiple inputs, which in the duct include major regulation by the WNK/SPAK pathway that inhibit secretion and the IRBIT/PP1 pathway that antagonize the effects of the WNK/SPAK pathway to both stimulate and coordinate the secretion. The function of these regulatory pathways in secretory glands acinar cells is yet to be examined. An important concept in biology is synergism among signaling pathways to generate the final physiological response that ensures regulation with high fidelity and guards against cell toxicity. While synergism is observed in all epithelial functions, the molecular mechanism mediating the synergism is not known. Recent work reveals a central role for IRBIT as a third messenger that integrates and synergizes the function of the Ca(2+) and cAMP signaling pathways in activation of epithelial fluid and electrolyte secretion. These concepts are discussed in this review using secretion by the pancreatic and salivary gland ducts as model systems.
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Affiliation(s)
- Jeong Hee Hong
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD, 20892, USA
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Modification of the salivary secretion assay in F508del mice--the murine equivalent of the human sweat test. J Cyst Fibros 2013; 12:630-7. [PMID: 23768658 DOI: 10.1016/j.jcf.2013.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 05/06/2013] [Accepted: 05/13/2013] [Indexed: 11/24/2022]
Abstract
BACKGROUND In 2005 Best and Quinton established the salivary secretion assay in mice for the in vivo characterization of new drugs against cystic fibrosis (CF). However, limited data are available and the predictive value of this in vivo assay for treatment effects in CF patients is not fully understood. METHODS Therefore, we revisited the salivary secretion assay and systematically investigated the salivary secretion rates in different murine backgrounds and sexes, as well as in different CF mouse models. Moreover, we established quantification of salivary chloride content. RESULTS We found a strain- and sex-dependency of salivary secretion rates and were able to confirm the decreased β-adrenergic salivary secretion response in CFTR knockout mice (CFTR(tm1Unc)) as well as in the F508del CFTR mice of different origins (CFTR(tm1Kth) and CFTR(tm1Eur)). In heterozygous Cftr+/- and Cftr+/F508del mice, the isoprenaline-stimulated salivary secretion rate and the Cl(-) content were intermediate between values measured in WT and CF mice, indicating that this assay is also able to detect CF carriership. Pilocarpine-induced abnormalities in saliva chloride content in CF mice resembled the changes observed in the human sweat test. CONCLUSIONS Determination of murine salivary chloride content in combination with salivary secretion rate in CF mice may render the salivary secretion assay as a powerful tool for validation of new CF treatments.
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Gonçalves AC, Marson FADL, Mendonça RMDH, Ribeiro JD, Ribeiro AF, Paschoal IA, Levy CE. Saliva as a potential tool for cystic fibrosis diagnosis. Diagn Pathol 2013; 8:46. [PMID: 23510227 PMCID: PMC3621375 DOI: 10.1186/1746-1596-8-46] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 03/10/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Saliva and sweat are modified by cystic fibrosis (CF). In both cases the chloride and sodium ion concentrations for healthy subjects and CF patients differ, this representing a possible alternative tool for CF diagnosis. In this context, the aim of this study was to compare the concentrations of these ions in saliva samples taken from CF patients and healthy subjects. METHODS A case-control study was carried out at a university CF center, in which the saliva samples were analyzed on an ABL 835 Radiometer® to determine the ion concentration. RESULTS For the CF patients (n = 80) the values for the biochemical parameters of chloride, potassium and sodium ion concentration were higher (p < 0.009) and the volume and pH of the saliva were lower than in the case of healthy subjects (p < 0.009). For the healthy subjects group (n = 84) versus CF patients, according to the ROC curve, the values for sodium were: cutoff: 13.5 mmol/L, sensitivity: 73.4%, specificity: 70.6%; and for chloride: cutoff: 20 mmol/L, sensitivity: 68.1%, specificity: 72.9%. CONCLUSIONS The chloride and sodium concentrations in the saliva samples were higher for CF patients in comparison with healthy subjects. Thus, saliva as a tool for CF diagnosis can be considered a new challenge, and a population study including patients in all age classes needs to be performed, in different countries over the world, to extend the database to include a broad spectrum of information in order to identify normal ion concentration ranges for CF patients according to age, genotype and environment. VIRTUAL SLIDES The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2614233148750145.
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Affiliation(s)
- Aline Cristina Gonçalves
- Department of Pediatrics, Faculty of Medical Sciences, University of Campinas, Campinas, SP, Brazil.
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Reddy MM, Stutts MJ. Status of fluid and electrolyte absorption in cystic fibrosis. Cold Spring Harb Perspect Med 2013; 3:a009555. [PMID: 23284077 DOI: 10.1101/cshperspect.a009555] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Salt and fluid absorption is a shared function of many of the body's epithelia, but its use is highly adapted to the varied physiological roles of epithelia-lined organs. These functions vary from control of hydration of outward-facing epithelial surfaces to conservation and regulation of total body volume. In the most general context, salt and fluid absorption is driven by active Na(+) absorption. Cl(-) is absorbed passively through various available paths in response to the electrical driving force that results from active Na(+) absorption. Absorption of salt creates a concentration gradient that causes water to be absorbed passively, provided the epithelium is water permeable. Key differences notwithstanding, the transport elements used for salt and fluid absorption are broadly similar in diverse epithelia, but the regulation of these elements enables salt absorption to be tailored to very different physiological needs. Here we focus on salt absorption by exocrine glands and airway epithelia. In cystic fibrosis, salt and fluid absorption by gland duct epithelia is effectively prevented by the loss of cystic fibrosis transmembrane conductance regulator (CFTR). In airway epithelia, salt and fluid absorption persists, in the absence of CFTR-mediated Cl(-) secretion. The contrast of these tissue-specific changes in CF tissues is illustrative of how salt and fluid absorption is differentially regulated to accomplish tissue-specific physiological objectives.
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Affiliation(s)
- M M Reddy
- Department of Pediatrics, UCSD School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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Patterson K, Catalán MA, Melvin JE, Yule DI, Crampin EJ, Sneyd J. A quantitative analysis of electrolyte exchange in the salivary duct. Am J Physiol Gastrointest Liver Physiol 2012; 303:G1153-63. [PMID: 22899825 PMCID: PMC3517652 DOI: 10.1152/ajpgi.00364.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A healthy salivary gland secretes saliva in two stages. First, acinar cells generate primary saliva, a plasma-like, isotonic fluid high in Na(+) and Cl(-). In the second stage, the ducts exchange Na(+) and Cl(-) for K(+) and HCO(3)(-), producing a hypotonic final saliva with no apparent loss in volume. We have developed a tool that aims to understand how the ducts achieve this electrolyte exchange while maintaining the same volume. This tool is part of a larger multiscale model of the salivary gland and can be used at the duct or gland level to investigate the effects of genetic and chemical alterations. In this study, we construct a radially symmetric mathematical model of the mouse salivary gland duct, representing the lumen, the cell, and the interstitium. For a given flow and primary saliva composition, we predict the potential differences and the luminal and cytosolic concentrations along a duct. Our model accounts well for experimental data obtained in wild-type animals as well as knockouts and chemical inhibitors. Additionally, the luminal membrane potential of the duct cells is predicted to be very depolarized compared with acinar cells. We investigate the effects of an electrogenic vs. electroneutral anion exchanger in the luminal membrane on concentration and the potential difference across the luminal membrane as well as how impairing the cystic fibrosis transmembrane conductance regulator channel affects other ion transporting mechanisms. Our model suggests the electrogenicity of the anion exchanger has little effect in the submandibular duct.
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Affiliation(s)
- Kate Patterson
- Dept. of Mathematics, Univ. of Auckland, Auckland, New Zealand.
| | - Marcelo A. Catalán
- 2Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland;
| | - James E. Melvin
- 2Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland;
| | - David I. Yule
- 3Department of Pharmacology and Physiology and the Center for Oral Biology, University of Rochester Medical Center, Rochester, New York; and
| | - Edmund J. Crampin
- 4Auckland Bioengineering Institute and Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - James Sneyd
- 1Department of Mathematics, University of Auckland, Auckland, New Zealand;
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Park HW, Lee MG. Transepithelial bicarbonate secretion: lessons from the pancreas. Cold Spring Harb Perspect Med 2012; 2:2/10/a009571. [PMID: 23028131 DOI: 10.1101/cshperspect.a009571] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Many cystic fibrosis transmembrane conductance regulator (CFTR)-expressing epithelia secrete bicarbonate (HCO(3)(-))-containing fluids. Recent evidence suggests that defects in epithelial bicarbonate secretion are directly involved in the pathogenesis of cystic fibrosis, in particular by building up hyperviscous mucus in the ductal structures of the lung and pancreas. Pancreatic juice is one of the representative fluids that contain a very high concentration of bicarbonate among bodily fluids that are secreted from CFTR-expressing epithelia. We introduce up-to-date knowledge on the basic principles of transepithelial bicarbonate transport by showing the mechanisms involved in pancreatic bicarbonate secretion. The model of pancreatic bicarbonate secretion described herein may also apply to other exocrine epithelia. As a central regulator of bicarbonate transport at the apical membrane, CFTR plays an essential role in both direct and indirect bicarbonate secretion. The major role of CFTR in bicarbonate secretion would be variable depending on the tissue and cell type. For example, in epithelial cells that produce a low concentration of bicarbonate-containing fluid (up to 80 mm), either CFTR-dependent Cl(-)/HCO(3)(-) exchange or CFTR anion channel with low bicarbonate permeability would be sufficient to generate such fluid. However, in cells that secrete high-bicarbonate-containing fluids, a highly selective CFTR bicarbonate channel activity is required. Therefore, understanding the molecular mechanism of transepithelial bicarbonate transport and the role of CFTR in each specific epithelium will provide therapeutic strategies to recover from epithelial defects induced by hyposecretion of bicarbonate in cystic fibrosis.
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Affiliation(s)
- Hyun Woo Park
- Department of Pharmacology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Korea
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Butterworth MB, Zhang L, Heidrich EM, Myerburg MM, Thibodeau PH. Activation of the epithelial sodium channel (ENaC) by the alkaline protease from Pseudomonas aeruginosa. J Biol Chem 2012; 287:32556-65. [PMID: 22859302 DOI: 10.1074/jbc.m112.369520] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that significantly contributes to the mortality of patients with cystic fibrosis. Chronic infection by Pseudomonas induces sustained immune and inflammatory responses and damage to the airway. The ability of Pseudomonas to resist host defenses is aided, in part, by secreted proteases, which act as virulence factors in multiple modes of infection. Recent studies suggest that misregulation of protease activity in the cystic fibrosis lung may alter fluid secretion and pathogen clearance by proteolytic activation of the epithelial sodium channel (ENaC). To evaluate the possibility that proteolytic activation of ENaC may contribute to the virulence of Pseudomonas, primary human bronchial epithelial cells were exposed to P. aeruginosa and ENaC function was assessed by short circuit current measurements. Apical treatment with a strain known to express high levels of alkaline protease (AP) resulted in an increase in basal ENaC current and a loss of trypsin-inducible ENaC current, consistent with sustained activation of ENaC. To further characterize this AP-induced ENaC activation, AP was purified, and its folding, activity, and ability to activate ENaC were assessed. AP folding was efficient under pH and calcium conditions thought to exist in the airway surface liquid of normal and cystic fibrosis (CF) lungs. Short circuit measurements of ENaC in polarized monolayers indicated that AP activated ENaC in immortalized cell lines as well as post-transplant, primary human bronchial epithelial cells from both CF and non-CF patients. This activation was mapped to the γ-subunit of ENaC. Based on these data, patho-mechanisms associated with AP in the CF lung are proposed wherein secretion of AP leads to decreased airway surface liquid volume and a corresponding decrease in mucocilliary clearance of pulmonary pathogens.
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Affiliation(s)
- Michael B Butterworth
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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Abstract
PURPOSE We investigated the role that the cystic fibrosis transmembrane conductance regulator (CFTR) may play in Cl(-) transport in the acinar and ductal epithelial cells of rabbit lacrimal gland (LG). METHODS Primary cultured LG acinar cells were processed for whole-cell patch-clamp electrophysiological recording of Cl(-) currents by using perfusion media with high and low [Cl(-)], 10 µM forskolin and 100 µM 3-isobutyl-1-methylxanthine (IBMX), the non-specific Cl(-) channel blocker 4,4'-disothiocyanostilbene-2, 2' sulphonic acid (DIDS; 100 µM) and CFTRinh-172 (10 µM), a specific blocker for CFTR. Ex vivo live cell imaging of [Cl(-)] changes in duct cells was performed on freshly dissected LG duct with a multiphoton confocal laser scanning microscope using a Cl(-) sensitive fluorescence dye, N-[ethoxycarbonylmethyl]-6-methoxy-quinolinium bromide. RESULTS Whole-cell patch-clamp studies demonstrated the presence of Cl(-) current in isolated acinar cells and revealed that this Cl(-) current was mediated by CFTR channel. Live cell imaging also showed the presence of CFTR-mediated Cl(-) transport across the plasma membrane of duct cells. CONCLUSIONS Our previous data showed the presence of CFTR in all acinar and duct cells within the rabbit LG, with expression most prominent in the apical membranes of duct cells. The present study demonstrates that CFTR is actively involved in Cl(-) transport in both acinar cells and epithelial cells from duct segments, suggesting that CFTR may play a significant role in LG secretion.
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Affiliation(s)
- Michael Lu
- Department of Cell and Neurobiology, Doheny Eye Institute, University of Southern California, Los Angeles, CA, USA
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Chuanqing Ding
- Department of Cell and Neurobiology, Doheny Eye Institute, University of Southern California, Los Angeles, CA, USA
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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Abstract
PURPOSE To test the hypothesis that expressions of Na-K-2Cl cotransporter-1 (NKCC1), cystic fibrosis transmembrane conductance regulator (CFTR), and chloride channel 2 γ subunit (ClC2γ) in the lacrimal glands (LGs) of rabbits with induced autoimmune dacryoadenitis (IAD) are changed. METHODS LGs were obtained from adult female rabbits with IAD and age-matched female control rabbits. LGs were processed for laser capture microdissection, real-time reverse transcription-polymerase chain reaction, Western blot, and immunofluorescence. RESULTS In rabbits with IAD, messenger RNA (mRNA) abundance and protein expressions of NKCC1 and CFTR from whole LGs were significantly lower than those in controls. mRNA abundance of NKCC1, CFTR, and ClC2γ from rabbits with IAD was significantly different from that in acinar and ductal cells from controls. NKCC1 was localized to the basolateral membranes of all acinar and ductal cells, with weaker staining intensity in ductal cells, and the staining pattern from rabbits with IAD appeared similar to that from controls. CFTR was found as punctate aggregates in the apical cytoplasm of all acinar and ductal cells, with the intensity in ductal cells much stronger and no significant difference between controls and rabbits with IAD. ClC2γ was also localized to the apical cytoplasm as punctate aggregates of all acinar cells but not in ductal cells, and a similar staining pattern was observed in rabbits with IAD compared with control rabbits. CONCLUSIONS Our data demonstrated significant changes of mRNA and protein expressions of NKCC1, CFTR, and ClC2γ in rabbits with IAD, suggesting that these changes may contribute to the altered lacrimal secretion, particularly Cl transport, in rabbits with IAD.
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Lee MG, Ohana E, Park HW, Yang D, Muallem S. Molecular mechanism of pancreatic and salivary gland fluid and HCO3 secretion. Physiol Rev 2012; 92:39-74. [PMID: 22298651 DOI: 10.1152/physrev.00011.2011] [Citation(s) in RCA: 275] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Fluid and HCO(3)(-) secretion is a vital function of all epithelia and is required for the survival of the tissue. Aberrant fluid and HCO(3)(-) secretion is associated with many epithelial diseases, such as cystic fibrosis, pancreatitis, Sjögren's syndrome, and other epithelial inflammatory and autoimmune diseases. Significant progress has been made over the last 20 years in our understanding of epithelial fluid and HCO(3)(-) secretion, in particular by secretory glands. Fluid and HCO(3)(-) secretion by secretory glands is a two-step process. Acinar cells secrete isotonic fluid in which the major salt is NaCl. Subsequently, the duct modifies the volume and electrolyte composition of the fluid to absorb the Cl(-) and secrete HCO(3)(-). The relative volume secreted by acinar and duct cells and modification of electrolyte composition of the secreted fluids varies among secretory glands to meet their physiological functions. In the pancreas, acinar cells secrete a small amount of NaCl-rich fluid, while the duct absorbs the Cl(-) and secretes HCO(3)(-) and the bulk of the fluid in the pancreatic juice. Fluid secretion appears to be driven by active HCO(3)(-) secretion. In the salivary glands, acinar cells secrete the bulk of the fluid in the saliva that is driven by active Cl(-) secretion and contains high concentrations of Na(+) and Cl(-). The salivary glands duct absorbs both the Na(+) and Cl(-) and secretes K(+) and HCO(3)(-). In this review, we focus on the molecular mechanism of fluid and HCO(3)(-) secretion by the pancreas and salivary glands, to highlight the similarities of the fundamental mechanisms of acinar and duct cell functions, and to point out the differences to meet gland-specific secretions.
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Affiliation(s)
- Min Goo Lee
- Department of Pharmacology, Yonsei University College of Medicine, Seoul, Korea
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Jia YH, Cui ZJ. Tri-phasic modulation of ACh- and NA-maintained calcium plateau by high potassium in isolated mouse submandibular granular convoluted tubular cells. Arch Oral Biol 2011; 56:1347-55. [PMID: 21704303 DOI: 10.1016/j.archoralbio.2011.05.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 04/20/2011] [Accepted: 05/29/2011] [Indexed: 02/07/2023]
Abstract
OBJECTIVES The fact that submandibular glands secrete a large amount of potassium ion upon nerve stimulation has long been recognized, but a physiological role for such high potassium in the saliva has never been systematically investigated. In the present work, high potassium effect has been investigated in the freshly isolated mouse submandibular granular convoluted tubules. DESIGN Isolated intact mouse submandibular granular convoluted tubules were loaded with Fura-2, and cytosolic calcium concentration in individual tubular cells was measured by microscopic fluorospectrometry. RESULTS It was found that high potassium had no effect on basal cytosolic calcium concentration, but had a tri-phasic modulation of the calcium plateau maintained by continued stimulation by acetylcholine (ACh) or noradrenaline (NA): a minor initial transient depression, followed by steady increase, completed by a robust calcium rebound spike upon removal of high potassium. The phase of steady increase was blocked without major effect on the plateau by KB-R 7943, a sodium/calcium exchange (NCX) inhibitor. CONCLUSION These data together suggest that high potassium in saliva bathing the mouse submandibular granular convoluted tubular cells has a potent feedback effect on ACh and NA stimulation, and sodium/calcium exchange is likely to play a major role in this process. Such positive feedback actions of high potassium may suggest a role for enhancing ACh- or NA-stimulated protein factor secretion from the granulated convoluted tubular cells.
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Affiliation(s)
- Yan Hong Jia
- Institute of Cell Biology, Beijing Normal University, Beijing 100875, China
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Roescher N, Lodde BM, Vosters JL, Tak PP, Catalan MA, Illei GG, Chiorini JA. Temporal changes in salivary glands of non-obese diabetic mice as a model for Sjögren's syndrome. Oral Dis 2011; 18:96-106. [PMID: 21914088 DOI: 10.1111/j.1601-0825.2011.01852.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Non-obese diabetic (NOD) mice develop an autoimmune exocrinopathy that shows similarities with Sjögren's syndrome. They provide an experimental model to study the pathoetiogenesis of this disease. MATERIALS AND METHODS Salivary gland (SG) function and salivary sodium content were measured in 8-, 12-, 16- and 20-week-old NOD and age-matched CB6 mice. In NOD mice, SG expression of phenotypic cell markers, B cell-stimulating and costimulatory molecules were evaluated. Cytokine levels were measured in serum and SG homogenates. RESULTS Microscopically evident SG inflammation in NOD mice was preceded by expression of intercellular adhesion molecule 1 on epithelial cells in the presence of macrophages and relatively high levels of cytokines. Next, an influx consisting of mainly T, B, natural killer, plasma and dendritic cells was seen. Most cytokines, except for interleukin (IL)12/IL23p40 and B cell-activating factor, decreased or remained stable over time, while glandular function deteriorated from 16 weeks of age onward compared with CB6 mice. CONCLUSION Sjögren's syndrome-like disease in NOD mice occurs in multiple stages; immunological and physiological abnormalities can be detected before focal inflammation appears and salivary output declines. Extrapolating this knowledge to human subjects could help in understanding the pathogenesis and aid the identification of potential therapeutic targets.
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Affiliation(s)
- N Roescher
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.
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Novak I. Purinergic signalling in epithelial ion transport: regulation of secretion and absorption. Acta Physiol (Oxf) 2011; 202:501-22. [PMID: 21073662 DOI: 10.1111/j.1748-1716.2010.02225.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Intracellular ATP, the energy source for many reactions, is crucial for the activity of plasma membrane pumps and, thus, for the maintenance of transmembrane ion gradients. Nevertheless, ATP and other nucleotides/nucleosides are also extracellular molecules that regulate diverse cellular functions, including ion transport. In this review, I will first introduce the main components of the extracellular ATP signalling, which have become known as the purinergic signalling system. With more than 50 components or processes, just at cell membranes, it ranks as one of the most versatile signalling systems. This multitude of system components may enable differentiated regulation of diverse epithelial functions. As epithelia probably face the widest variety of potential ATP-releasing stimuli, a special attention will be given to stimuli and mechanisms of ATP release with a focus on exocytosis. Subsequently, I will consider membrane transport of major ions (Cl(-) , HCO(3)(-) , K(+) and Na(+) ) and integrate possible regulatory functions of P2Y2, P2Y4, P2Y6, P2Y11, P2X4, P2X7 and adenosine receptors in some selected epithelia at the cellular level. Some purinergic receptors have noteworthy roles. For example, many studies to date indicate that the P2Y2 receptor is one common denominator in regulating ion channels on both the luminal and basolateral membranes of both secretory and absorptive epithelia. In exocrine glands though, P2X4 and P2X7 receptors act as cation channels and, possibly, as co-regulators of secretion. On an organ level, both receptor types can exert physiological functions and together with other partners in the purinergic signalling, integrated models for epithelial secretion and absorption are emerging.
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Affiliation(s)
- I Novak
- Department of Biology, August Krogh Building, University of Copenhagen, Denmark.
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Mouse models of cystic fibrosis: Phenotypic analysis and research applications. J Cyst Fibros 2011; 10 Suppl 2:S152-71. [DOI: 10.1016/s1569-1993(11)60020-9] [Citation(s) in RCA: 167] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Catalán MA, Scott-Anne K, Klein MI, Koo H, Bowen WH, Melvin JE. Elevated incidence of dental caries in a mouse model of cystic fibrosis. PLoS One 2011; 6:e16549. [PMID: 21304986 PMCID: PMC3031584 DOI: 10.1371/journal.pone.0016549] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 12/23/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Dental caries is the single most prevalent and costly infectious disease worldwide, affecting more than 90% of the population in the U.S. The development of dental cavities requires the colonization of the tooth surface by acid-producing bacteria, such as Streptococcus mutans. Saliva bicarbonate constitutes the main buffering system which neutralizes the pH fall generated by the plaque bacteria during sugar metabolism. We found that the saliva pH is severely decreased in a mouse model of cystic fibrosis disease (CF). Given the close relationship between pH and caries development, we hypothesized that caries incidence might be elevated in the mouse CF model. METHODOLOGY/PRINCIPAL FINDINGS We induced carious lesions in CF and wildtype mice by infecting their oral cavity with S. mutans, a well-studied cariogenic bacterium. After infection, the mice were fed a high-sucrose diet for 5 weeks (diet 2000). The mice were then euthanized and their jaws removed for caries scoring and bacterial counting. A dramatic increase in caries and severity of lesions scores were apparent in CF mice compared to their wildtype littermates. The elevated incidence of carious lesions correlated with a striking increase in the S. mutans viable population in dental plaque (20-fold increase in CF vs. wildtype mice; p value < 0.003; t test). We also found that the pilocarpine-stimulated saliva bicarbonate concentration was significantly reduced in CF mice (16 ± 2 mM vs. 31 ± 2 mM, CF and wildtype mice, respectively; p value < 0.01; t test). CONCLUSIONS/SIGNIFICANCE Considering that bicarbonate is the most important pH buffering system in saliva, and the adherence and survival of aciduric bacteria such as S. mutans are enhanced at low pH values, we speculate that the decrease in the bicarbonate content and pH buffering of the saliva is at least partially responsible for the increased severity of lesions observed in the CF mouse.
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Affiliation(s)
- Marcelo A. Catalán
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Kathleen Scott-Anne
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Marlise I. Klein
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Hyun Koo
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - William H. Bowen
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - James E. Melvin
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, United States of America
- * E-mail:
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Kondo Y, Nakamoto T, Mukaibo T, Kidokoro M, Masaki C, Hosokawa R. Cevimeline-induced monophasic salivation from the mouse submandibular gland: decreased Na+ content in saliva results from specific and early activation of Na+/H+ exchange. J Pharmacol Exp Ther 2011; 337:267-74. [PMID: 21239510 DOI: 10.1124/jpet.110.174946] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cevimeline and pilocarpine are muscarinic agonists used clinically to treat dry mouth. In this study, we explored fluid secretion from mouse submandibular glands to determine the mechanism of cevimeline, pilocarpine, and an experimentally used agent carbachol. Cevimeline evoked almost the same amount of secretion at concentrations from 30 μM to 1 mM. Pilocarpine also induced secretion at a concentration as low as 1 μM and was the most powerful secretagogue at 10 μM. Secretion was induced by carbachol at 0.1 μM, with maximum secretion at 1.0 μM. Cevimeline induced monophasic secretion at all concentrations tested, whereas higher concentrations of pilocarpine and carbachol induced secretion with variable kinetics, i.e., an initial transient high flow rate, followed by decreased secretion after 2 to 3 min. In the presence of an epithelial Na(+) channel blocker, amiloride, neither carbachol nor pilocarpine affected the Na(+) level of secreted saliva; however, it significantly increased the Na(+) content of cevimeline-induced saliva. The intracellular Ca(2+) response of acinar cells was almost identical among all three agents, although recovery after drug removal was slower for cevimeline and pilocarpine. A profound decrease in intracellular pH was observed during pilocarpine and carbachol treatment, whereas intracellular acidification induced by cevimeline was only seen in the presence of a Na(+)/H(+) exchange inhibitor. When external HCO(3)(-) was removed, cevimeline-induced saliva significantly decreased. These findings suggest that cevimeline specifically activates Na(+)/H(+) exchange and may promote Na(+) reabsorption by stabilizing epithelial sodium channel activity.
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Affiliation(s)
- Yusuke Kondo
- Department of Oral Reconstruction and Rehabilitation, Kyushu Dental College, Kitakyushu City, Japan
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