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Zhan B, Zhou T, Tong D, Xu Z, Liang X, Ma A, Lü S. Expression of the non-neuronal cholinergic system components in Malpighian tubules of Mythimna separata and evidence for non-neuronal acetylcholine synthesis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 164:104047. [PMID: 38072082 DOI: 10.1016/j.ibmb.2023.104047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/28/2023] [Accepted: 11/28/2023] [Indexed: 12/17/2023]
Abstract
The non-neuronal cholinergic system, widely distributed in nature, is an ancient system that has not been well studied in insects. This study aims to investigate the key components of the cholinergic system and to identify the non-neuronal acetylcholine (ACh)-producing cells and the acting sites of ACh in the Malpighian tubules (MTs) of Mythimna separata. We found that non-neuronal ACh in MTs is synthesized by carnitine acetyltransferase (CarAT), rather than choline acetyltransferase (ChAT), as confirmed by using enzyme inhibitors and high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS). Fluorescence in situ hybridization revealed the presence of CarAT mRNA within MTs, specifically localized in the principal cells. Immunohistochemistry showed strong staining for A-mAChR, a muscarinic acetylcholine receptor, in the principal cells. Pharmacological analysis further demonstrated that ACh acts through A-mAChR in the principal cells to increase the intracellular Ca2+ concentration. These findings provide compelling evidence for the existence of a non-neuronal cholinergic system in the MTs of M. separata, and the principal cells play a crucial role in ACh synthesis via CarAT.
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Affiliation(s)
- Baolei Zhan
- Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, Entomological Museum, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Ting Zhou
- Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, Entomological Museum, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Di Tong
- Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, Entomological Museum, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Zile Xu
- Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, Entomological Museum, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Xiaoyu Liang
- Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, Entomological Museum, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Anqi Ma
- Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, Entomological Museum, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Shumin Lü
- Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, Entomological Museum, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China.
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Rose SC, Larsen M, Xie Y, Sharfstein ST. Salivary Gland Bioengineering. Bioengineering (Basel) 2023; 11:28. [PMID: 38247905 PMCID: PMC10813147 DOI: 10.3390/bioengineering11010028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/19/2023] [Accepted: 11/30/2023] [Indexed: 01/23/2024] Open
Abstract
Salivary gland dysfunction affects millions globally, and tissue engineering may provide a promising therapeutic avenue. This review delves into the current state of salivary gland tissue engineering research, starting with a study of normal salivary gland development and function. It discusses the impact of fibrosis and cellular senescence on salivary gland pathologies. A diverse range of cells suitable for tissue engineering including cell lines, primary salivary gland cells, and stem cells are examined. Moreover, the paper explores various supportive biomaterials and scaffold fabrication methodologies that enhance salivary gland cell survival, differentiation, and engraftment. Innovative engineering strategies for the improvement of vascularization, innervation, and engraftment of engineered salivary gland tissue, including bioprinting, microfluidic hydrogels, mesh electronics, and nanoparticles, are also evaluated. This review underscores the promising potential of this research field for the treatment of salivary gland dysfunction and suggests directions for future exploration.
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Affiliation(s)
- Stephen C. Rose
- Department of Nanoscale Science and Engineering, College of Nanotechnology, Science, and Engineering, University at Albany, SUNY, 257 Fuller Road, Albany, NY 12203, USA (Y.X.)
| | - Melinda Larsen
- Department of Biological Sciences and The RNA Institute, University at Albany, SUNY, 1400 Washington Ave., Albany, NY 12222, USA;
| | - Yubing Xie
- Department of Nanoscale Science and Engineering, College of Nanotechnology, Science, and Engineering, University at Albany, SUNY, 257 Fuller Road, Albany, NY 12203, USA (Y.X.)
| | - Susan T. Sharfstein
- Department of Nanoscale Science and Engineering, College of Nanotechnology, Science, and Engineering, University at Albany, SUNY, 257 Fuller Road, Albany, NY 12203, USA (Y.X.)
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3
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Dos Santos HT, Nam K, Brown CT, Dean SM, Lewis S, Pfeifer CS, Lei P, Petris MJ, Andreadis ST, Baker OJ. Trimers Conjugated to Fibrin Hydrogels Promote Salivary Gland Function. J Dent Res 2020; 100:268-275. [PMID: 33043768 DOI: 10.1177/0022034520964784] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
New strategies for tissue engineering have great potential for restoring and revitalizing impaired tissues and organs, including the use of smart hydrogels that can be modified to enhance organization and functionality of the salivary glands. For instance, monomers of laminin-111 peptides chemically conjugated to fibrin hydrogel (L1pM-FH) promote cell cluster formation in vitro and salivary gland regeneration in vivo when compared with fibrin hydrogel (FH) alone; however, L1pM-FH produce only weak expression of acinar differentiation markers in vivo (e.g., aquaporin-5 and transmembrane protein 16). Since previous studies demonstrated that a greater impact can be achieved when trimeric forms were used as compared with monomeric or dimeric forms, we investigated the extent to which trimers of laminin-111 chemically conjugated to FH (L1pT-FH) can increase the expression of acinar differentiation markers and elevate saliva secretion. In vitro studies using Par-C10 acinar cells demonstrated that when compared with L1pM-FH, L1pT-FH induced similar levels of acinar-like cell clustering, polarization, lumen formation, and calcium signaling. To assess the performance of the trimeric complex in vivo, we compared the ability of L1pM-FH and L1pT-FH to increase acinar differentiation markers and restore saliva flow rate in a salivary gland wound model of C57BL/6 mice. Our results show that L1pT-FH applied to wounded mice significantly improved the expression of the acinar differentiation markers and saliva secretion when compared with the monomeric form. Together, these positive effects of L1pT-FH warrant its future testing in additional models of hyposalivation with the ultimate goal of applying this technology in humans.
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Affiliation(s)
- H T Dos Santos
- Christopher S. Bond Life Sciences Center, University of Missouri-Columbia, Columbia, MO, USA.,Department of Otolaryngology-Head and Neck Surgery, School of Medicine, University of Missouri-Columbia, Columbia, MO, USA
| | - K Nam
- Christopher S. Bond Life Sciences Center, University of Missouri-Columbia, Columbia, MO, USA.,Department of Otolaryngology-Head and Neck Surgery, School of Medicine, University of Missouri-Columbia, Columbia, MO, USA
| | - C T Brown
- School of Dentistry, The University of Utah, Salt Lake City, UT, USA
| | - S M Dean
- School of Dentistry, The University of Utah, Salt Lake City, UT, USA
| | - S Lewis
- Division of Biomaterials and Biomechanics, Department of Restorative Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - C S Pfeifer
- Division of Biomaterials and Biomechanics, Department of Restorative Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - P Lei
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - M J Petris
- Christopher S. Bond Life Sciences Center, University of Missouri-Columbia, Columbia, MO, USA.,Department of Ophthalmology, School of Medicine, University of Missouri-Columbia, Columbia, MO, USA.,Department of Biochemistry, School of Medicine, University of Missouri-Columbia, Columbia, MO, USA
| | - S T Andreadis
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA.,Department of Biomedical Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA.,Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - O J Baker
- Christopher S. Bond Life Sciences Center, University of Missouri-Columbia, Columbia, MO, USA.,Department of Otolaryngology-Head and Neck Surgery, School of Medicine, University of Missouri-Columbia, Columbia, MO, USA.,Department of Biochemistry, School of Medicine, University of Missouri-Columbia, Columbia, MO, USA
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4
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Khalafalla MG, Woods LT, Jasmer KJ, Forti KM, Camden JM, Jensen JL, Limesand KH, Galtung HK, Weisman GA. P2 Receptors as Therapeutic Targets in the Salivary Gland: From Physiology to Dysfunction. Front Pharmacol 2020; 11:222. [PMID: 32231563 PMCID: PMC7082426 DOI: 10.3389/fphar.2020.00222] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 02/18/2020] [Indexed: 12/12/2022] Open
Abstract
Although often overlooked in our daily lives, saliva performs a host of necessary physiological functions, including lubricating and protecting the oral cavity, facilitating taste sensation and digestion and maintaining tooth enamel. Therefore, salivary gland dysfunction and hyposalivation, often resulting from pathogenesis of the autoimmune disease Sjögren's syndrome or from radiotherapy of the head and neck region during cancer treatment, severely reduce the quality of life of afflicted patients and can lead to dental caries, periodontitis, digestive disorders, loss of taste and difficulty speaking. Since their initial discovery in the 1970s, P2 purinergic receptors for extracellular nucleotides, including ATP-gated ion channel P2X and G protein-coupled P2Y receptors, have been shown to mediate physiological processes in numerous tissues, including the salivary glands where P2 receptors represent a link between canonical and non-canonical saliva secretion. Additionally, extracellular nucleotides released during periods of cellular stress and inflammation act as a tissue alarmin to coordinate immunological and tissue repair responses through P2 receptor activation. Accordingly, P2 receptors have gained widespread clinical interest with agonists and antagonists either currently undergoing clinical trials or already approved for human use. Here, we review the contributions of P2 receptors to salivary gland function and describe their role in salivary gland dysfunction. We further consider their potential as therapeutic targets to promote physiological saliva flow, prevent salivary gland inflammation and enhance tissue regeneration.
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Affiliation(s)
- Mahmoud G. Khalafalla
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Lucas T. Woods
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Kimberly J. Jasmer
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Kevin Muñoz Forti
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Jean M. Camden
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Janicke L. Jensen
- Institute of Clinical Dentistry, Section of Oral Surgery and Oral Medicine, University of Oslo, Oslo, Norway
| | - Kirsten H. Limesand
- Department of Nutritional Sciences, University of Arizona, Tucson, AZ, United States
| | - Hilde K. Galtung
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - Gary A. Weisman
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
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5
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Rawangwong A, Pidsaya A, Thoungseabyoun W, Tachow A, Sawatpanich T, Sakaew W, Yamasaki M, Watanabe M, Kondo H, Hipkaeo W. Localization of phospholipase C β3 in the major salivary glands of adult mice. Acta Histochem 2019; 121:484-490. [PMID: 31003695 DOI: 10.1016/j.acthis.2019.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 03/28/2019] [Accepted: 04/12/2019] [Indexed: 01/24/2023]
Abstract
Phospholipase C (PLC)β has a role in saliva secretion by controlling intracellular Ca2+via its product, IP3. The present study was attempted to localize PLCβ isoforms in mouse salivary glands in situ. A single major band was detected for PLCβ3 in immunoblots of the parotid and sublingual glands (PG, SLG), while no such band was seen in the submandibular gland (SMG). No bands were detected for PLCβ1 or 4 in the three glands. In immuno-light microscopy of PG and SLG, substantial immunoreactivity for PLCβ3 was seen in the cytoplasm including the plasmalemma of almost all ductal cells, while no distinct immunoreactivity was discerned in most acinar cells except for sublingual demilune cells. Numerous ductal cells exhibited higher immunoreactivity for PLCβ3 in their apical/supranuclear cell domain including the plasmalemma than in the basal/infranuclear domain, indicating an apico-basal polarity. In immuno-gold electron microscopy of PG ducts and SLG ducts and demilunes, most gold particles were found in association with plasma membranes as well as various intracellular membranes, most of which formed small oblong or flattened vesicles and vacuoles. A few particles were seen without association with any membranous structures. The present finding supports the previous physio-pharmacological result that Ca2+-signaling proteins as well as initial intracellular Ca2+ changes occur in the apical cell domain including the plasma membranes of the exocrine cells.
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6
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Rawangwong A, Khrongyut S, Chomphoo S, Konno K, Yamasaki M, Watanabe M, Kondo H, Hipkaeo W. Heterogeneous localization of muscarinic cholinoceptor M 1 in the salivary ducts of adult mice. Arch Oral Biol 2019; 100:14-22. [PMID: 30743058 DOI: 10.1016/j.archoralbio.2019.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/31/2019] [Accepted: 02/03/2019] [Indexed: 11/24/2022]
Abstract
We hypothesize variation in expression and localization, along the course of the glandular tubule, of muscarinic cholinergic receptor M1 which plays as a distinct contribution, though minor in comparison with M3 receptor, in saliva secretion. Localization of the M1 receptor was examined using immunohistochemistry in three major salivary glands. Although all glandular cells were more or less M1-immunoreactive, acinar cells were weakly immunoreactive, while ductal cells exhibited substantial M1-immunoreactivity. Many ductal cells exhibited clear polarity with higher immunoreactivity in their apical/supra-nuclear domain. However, some exhibited indistinct polarity because of additional higher immunoreactivity in their basal/infra-nuclear domain. A small group of cells with intense immunoreactivity was found, mostly located in the intercalated ducts or in portions of the striated ducts close to the intercalated ducts. In immuno-electron microscopy, the immunoreactive materials were mainly in the cytoplasm including various vesicles and vacuoles. Unexpectedly, distinct immunoreactivity on apical and basal plasma membranes was infrequent in most ductal cells. The heterogeneous localization of M1-immunoreactivity along the gland tubular system is discussed in view of possible modulatory roles of the M1 receptor in saliva secretion.
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Affiliation(s)
- Atsara Rawangwong
- Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Suthankamon Khrongyut
- Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Surang Chomphoo
- Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Kohtaro Konno
- Department of Anatomy and Embryology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Miwako Yamasaki
- Department of Anatomy and Embryology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Masahiko Watanabe
- Department of Anatomy and Embryology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hisatake Kondo
- Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Department of Organ Anatomy, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Wiphawi Hipkaeo
- Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
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7
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Contribution of HIV Infection, AIDS, and Antiretroviral Therapy to Exocrine Pathogenesis in Salivary and Lacrimal Glands. Int J Mol Sci 2018; 19:ijms19092747. [PMID: 30217034 PMCID: PMC6164028 DOI: 10.3390/ijms19092747] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/04/2018] [Accepted: 09/07/2018] [Indexed: 02/07/2023] Open
Abstract
The structure and function of exocrine glands are negatively affected by human immunodeficiency virus (HIV) infection and its co-morbidities, including innate and adaptive immune responses. At the same time, exocrine function may also be influenced by pharmacotherapies directed at the infectious agents. Here, we briefly review the role of the salivary glands and lacrimal glands in normal physiology and exocrine pathogenesis within the context of HIV infection and acquired immune deficiency syndrome (AIDS), including the contribution of antiretroviral therapies on both. Subsequently, we discuss the impact of HIV infection and the types of antiretroviral therapy on disease management and therapy development efforts.
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8
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Nam K, Jones JP, Lei P, Andreadis ST, Baker OJ. Laminin-111 Peptides Conjugated to Fibrin Hydrogels Promote Formation of Lumen Containing Parotid Gland Cell Clusters. Biomacromolecules 2016; 17:2293-301. [PMID: 27151393 PMCID: PMC5029268 DOI: 10.1021/acs.biomac.6b00588] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Previous studies showed that mouse submandibular gland cells form three-dimensional structures when grown on Laminin-111 gels. The use of Laminin-111 for tissue bioengineering is complicated due to its lack of purity. By contrast, the use of synthetic peptides derived from Laminin-111 is beneficial due to their high purity and easy manipulation. Two Laminin-111 peptides have been identified for salivary cells: the A99 peptide corresponding to the α1 chain from Laminin-111 and the YIGSR peptide corresponding to the β1 chain from Laminin-111, which are important for cell adhesion and migration. We created three-dimensional salivary cell clusters using a modified fibrin hydrogel matrix containing immobilized Laminin-111 peptides. Results indicate that the YIGSR peptide improved morphology and lumen formation in rat parotid Par-C10 cells as compared to cells grown on unmodified fibrin hydrogel. Moreover, a combination of both peptides not only allowed the formation of functional three-dimensional salivary cell clusters but also increased attachment and number of cell clusters. In summary, we demonstrated that fibrin hydrogel decorated with Laminin-111 peptides supports attachment and differentiation of salivary gland cell clusters with mature lumens.
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Affiliation(s)
- Kihoon Nam
- School of Dentistry, The University of Utah, Salt Lake City, Utah 84108, United States
| | - Joshua P. Jones
- Department of Bioengineering, The University of Utah, Salt Lake City, Utah 84108, United States
| | - Pedro Lei
- Department of Chemical and Biological Engineering, School of Engineering and Applied Sciences, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Stelios T. Andreadis
- Department of Chemical and Biological Engineering, School of Engineering and Applied Sciences, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
- Department of Biomedical Engineering, School of Engineering and Applied Sciences, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
- Center of Bioinformatics and Life Sciences, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Olga J. Baker
- School of Dentistry, The University of Utah, Salt Lake City, Utah 84108, United States
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9
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Abstract
Salivary gland bioengineering requires understanding the interaction between salivary epithelium and surrounding tissues. An important component of salivary glands is the presence of neurons. No previous studies have investigated how neurons and salivary epithelial cells interact in an in vitro co-culture model. In this study, we describe the self-organization of neurons around salivary epithelial cells in co-culture, in a similar fashion to what occurs in native tissue. We cultured primary mouse cortical neurons (m-CN) with a salivary epithelial cell line (Par-C10) on growth factor-reduced Matrigel (GFR-MG) for 4 days. After this time, co-cultures were compared with native salivary glands using confocal microscopy. Our findings indicate that m-CN were able to self-organize basolaterally to salivary epithelial cell clusters in a similar manner to what occurs in native tissue. These results indicate that this model can be developed as a potential platform for studying neuron-salivary epithelial cell interactions for bioengineering purposes.
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Affiliation(s)
- Salah Sommakia
- School of Dentistry, the University of Utah, Salt Lake City, UT, USA
| | - Olga J Baker
- School of Dentistry, the University of Utah, Salt Lake City, UT, USA
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10
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El-Sayed FG, Camden JM, Woods LT, Khalafalla MG, Petris MJ, Erb L, Weisman GA. P2Y2 nucleotide receptor activation enhances the aggregation and self-organization of dispersed salivary epithelial cells. Am J Physiol Cell Physiol 2014; 307:C83-96. [PMID: 24760984 DOI: 10.1152/ajpcell.00380.2013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Hyposalivation resulting from salivary gland dysfunction leads to poor oral health and greatly reduces the quality of life of patients. Current treatments for hyposalivation are limited. However, regenerative medicine to replace dysfunctional salivary glands represents a revolutionary approach. The ability of dispersed salivary epithelial cells or salivary gland-derived progenitor cells to self-organize into acinar-like spheres or branching structures that mimic the native tissue holds promise for cell-based reconstitution of a functional salivary gland. However, the mechanisms involved in salivary epithelial cell aggregation and tissue reconstitution are not fully understood. This study investigated the role of the P2Y2 nucleotide receptor (P2Y2R), a G protein-coupled receptor that is upregulated following salivary gland damage and disease, in salivary gland reconstitution. In vitro results with the rat parotid acinar Par-C10 cell line indicate that P2Y2R activation with the selective agonist UTP enhances the self-organization of dispersed salivary epithelial cells into acinar-like spheres. Other results indicate that the P2Y2R-mediated response is dependent on epidermal growth factor receptor activation via the metalloproteases ADAM10/ADAM17 or the α5β1 integrin/Cdc42 signaling pathway, which leads to activation of the MAPKs JNK and ERK1/2. Ex vivo data using primary submandibular gland cells from wild-type and P2Y2R(-/-) mice confirmed that UTP-induced migratory responses required for acinar cell self-organization are mediated by the P2Y2R. Overall, this study suggests that the P2Y2R is a promising target for salivary gland reconstitution and identifies the involvement of two novel components of the P2Y2R signaling cascade in salivary epithelial cells, the α5β1 integrin and the Rho GTPase Cdc42.
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Affiliation(s)
- Farid G El-Sayed
- Department of Biochemistry, University of Missouri, Columbia, Missouri; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri
| | - Jean M Camden
- Department of Biochemistry, University of Missouri, Columbia, Missouri; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri
| | - Lucas T Woods
- Department of Biochemistry, University of Missouri, Columbia, Missouri; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri
| | - Mahmoud G Khalafalla
- Department of Biochemistry, University of Missouri, Columbia, Missouri; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri
| | - Michael J Petris
- Department of Biochemistry, University of Missouri, Columbia, Missouri; Department of Nutritional Sciences and Exercise Physiology, University of Missouri, Columbia, Missouri; and Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri
| | - Laurie Erb
- Department of Biochemistry, University of Missouri, Columbia, Missouri; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri
| | - Gary A Weisman
- Department of Biochemistry, University of Missouri, Columbia, Missouri; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri
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11
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Fu JL, Zhang HM, Zhang H, Kamat A, Yeh CK, Zhang BX. A melatonin-based fluorescence method for the measurement of mitochondrial complex III function in intact cells. J Pineal Res 2013; 55:364-70. [PMID: 23952718 PMCID: PMC4450748 DOI: 10.1111/jpi.12079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 07/19/2013] [Indexed: 01/22/2023]
Abstract
Mitochondrial complex III (MC-3) plays a pivotal role in electron transfer and oxidative phosphorylation. Impaired MC-3 functions may contribute to a variety of diseases by interrupting normal bioenergetics and increasing reactive oxygen production and oxidative stress. Currently, MC-3 function is assessed by measuring the cytochrome c reductase activity spectrophotometrically in isolated mitochondria or MC-3. The cytoplasmic microenvironment critical for mitochondrial complex functions may be depleted during these isolation processes. The development of a reliable method to measure MC-3 activities in intact cells or tissues is highly desirable. This report describes a novel fluorescence-based method to assess MC-3 functions, i.e., Qi site electron transfer, in the intact cells. Human mesangial and teratocarcinoma NT2 cells were used to demonstrate that melatonin-induced oxidation of 2',7'-dichlorodihydrofluorescein (H2 DCF) was inhibited by antimycin A, the MC-3 Qi site-specific inhibitor, but not by myxothiazol, the MC-3 Qo site-specific inhibitor, nor rotenone, the mitochondrial complex I inhibitor. These results indicate that melatonin-induced oxidation of H2 DCF is reflecting MC-3 Qi site electron transfer activities. Modifying structures of the side groups at the R3 and R5 positions of the indole ring of melatonin diminished its efficacy for inducing H2 DCF oxidation, suggesting a specific interaction of melatonin with the MC-3 Qi site. These results suggest that the fluorogenic property of melatonin-induced H2 DCF oxidation provides a MC-3 Qi site electron transfer-specific measurement in intact cells. Interestingly, using this method, the Qi site electron transfer activity in transformed or immortalized cells was found to be significantly higher than the nontransformed cells.
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Affiliation(s)
- Jian-Liang Fu
- Department of Neurology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
- Geriatric Research, Education and Clinical Center, Audie L Murphy Division, South Texas Veterans Health Care System
| | - Hong-Mei Zhang
- Geriatric Research, Education and Clinical Center, Audie L Murphy Division, South Texas Veterans Health Care System
| | - Hua Zhang
- Geriatric Research, Education and Clinical Center, Audie L Murphy Division, South Texas Veterans Health Care System
| | - Amrita Kamat
- Geriatric Research, Education and Clinical Center, Audie L Murphy Division, South Texas Veterans Health Care System
| | - Chih-Ko Yeh
- Geriatric Research, Education and Clinical Center, Audie L Murphy Division, South Texas Veterans Health Care System
- Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Bin-Xian Zhang
- Geriatric Research, Education and Clinical Center, Audie L Murphy Division, South Texas Veterans Health Care System
- Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- To whom correspondence should be addressed. Tel.: 210-617-5197; Fax: 210-617-5312;
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12
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Soscia DA, Sequeira SJ, Schramm RA, Jayarathanam K, Cantara SI, Larsen M, Castracane J. Salivary gland cell differentiation and organization on micropatterned PLGA nanofiber craters. Biomaterials 2013; 34:6773-84. [PMID: 23777914 PMCID: PMC3755621 DOI: 10.1016/j.biomaterials.2013.05.061] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 05/24/2013] [Indexed: 12/20/2022]
Abstract
There is a need for an artificial salivary gland as a long-term remedy for patients suffering from salivary hypofunction, a leading cause of chronic xerostomia (dry mouth). Current salivary gland tissue engineering approaches are limited in that they either lack sufficient physical cues and surface area needed to facilitate epithelial cell differentiation, or they fail to provide a mechanism for assembling an interconnected branched network of cells. We have developed highly-ordered arrays of curved hemispherical "craters" in polydimethylsiloxane (PDMS) using wafer-level integrated circuit (IC) fabrication processes, and lined them with electrospun poly-lactic-co-glycolic acid (PLGA) nanofibers, designed to mimic the three-dimensional (3-D) in vivo architecture of the basement membrane surrounding spherical acini of salivary gland epithelial cells. These micropatterned scaffolds provide a method for engineering increased surface area and were additionally investigated for their ability to promote cell polarization. Two immortalized salivary gland cell lines (SIMS, ductal and Par-C10, acinar) were cultured on fibrous crater arrays of various radii and compared with those grown on flat PLGA nanofiber substrates, and in 3-D Matrigel. It was found that by increasing crater curvature, the average height of the cell monolayer of SIMS cells and to a lesser extent, Par-C10 cells, increased to a maximum similar to that seen in cells grown in 3-D Matrigel. Increasing curvature resulted in higher expression levels of tight junction protein occludin in both cell lines, but did not induce a change in expression of adherens junction protein E-cadherin. Additionally, increasing curvature promoted polarity of both cell lines, as a greater apical localization of occludin was seen in cells on substrates of higher curvature. Lastly, substrate curvature increased expression of the water channel protein aquaporin-5 (Aqp-5) in Par-C10 cells, suggesting that curved nanofiber substrates are more suitable for promoting differentiation of salivary gland cells.
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Affiliation(s)
- David A. Soscia
- College of Nanoscale Science and Engineering, University at Albany, State University of New York, 257 Fuller Road, Albany, NY 12203, USA
| | - Sharon J. Sequeira
- Dept. of Biological Sciences, University at Albany, State University of New York, 1400 Washington Avenue, Life Sciences Bldg., Albany, NY 12222, USA
| | - Robert A. Schramm
- College of Nanoscale Science and Engineering, University at Albany, State University of New York, 257 Fuller Road, Albany, NY 12203, USA
| | - Kavitha Jayarathanam
- College of Nanoscale Science and Engineering, University at Albany, State University of New York, 257 Fuller Road, Albany, NY 12203, USA
| | - Shraddha I. Cantara
- Dept. of Biological Sciences, University at Albany, State University of New York, 1400 Washington Avenue, Life Sciences Bldg., Albany, NY 12222, USA
| | - Melinda Larsen
- Dept. of Biological Sciences, University at Albany, State University of New York, 1400 Washington Avenue, Life Sciences Bldg., Albany, NY 12222, USA
| | - James Castracane
- College of Nanoscale Science and Engineering, University at Albany, State University of New York, 257 Fuller Road, Albany, NY 12203, USA
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Soltoff SP, Lannon WA. Activation of ERK1/2 by store-operated calcium entry in rat parotid acinar cells. PLoS One 2013; 8:e72881. [PMID: 24009711 PMCID: PMC3756958 DOI: 10.1371/journal.pone.0072881] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 07/15/2013] [Indexed: 12/23/2022] Open
Abstract
The regulation of intracellular Ca2+ concentration ([Ca2+]i) plays a critical role in a variety of cellular processes, including transcription, protein activation, vesicle trafficking, and ion movement across epithelial cells. In many cells, the activation of phospholipase C-coupled receptors hydrolyzes membrane phosphoinositides and produces the depletion of endoplasmic reticulum Ca2+ stores, followed by the sustained elevation of [Ca2+]i from Ca2+ entry across the plasma membrane via store-operated Ca2+ entry (SOCE). Ca2+ entry is also increased in a store-independent manner by arachidonate-regulated Ca2+ (ARC) channels. Using rat parotid salivary gland cells, we examined multiple pathways of Ca2+ entry/elevation to determine if they activated cell signaling proteins and whether this occurred in a pathway-dependent manner. We observed that SOCE activates extracellular signal-related kinases 1 and 2 (ERK1/2) to ∼3-times basal levels via a receptor-independent mechanism when SOCE was initiated by depleting Ca2+ stores using the endoplasmic reticulum Ca2+-ATPase inhibitor thapsigargin (TG). TG-initiated ERK1/2 phosphorylation increased as rapidly as that initiated by the muscarinic receptor agonist carbachol, which promoted an increase to ∼5-times basal levels. Notably, ERK1/2 phosphorylation was not increased by the global elevation of [Ca2+]i by Ca2+ ionophore or by Ca2+ entry via ARC channels in native cells, although ERK1/2 phosphorylation was increased by Ca2+ ionophore in Par-C10 and HSY salivary cell lines. Agents and conditions that blocked SOCE in native cells, including 2-aminoethyldiphenyl borate (2-APB), SKF96363, and removal of extracellular Ca2+, also reduced TG- and carbachol-stimulated ERK1/2 phosphorylation. TG-promoted ERK1/2 phosphorylation was blocked when SRC and Protein Kinases C (PKC) were inhibited, and it was blocked in cells pretreated with β-adrenergic agonist isoproterenol. These observations demonstrate that ERK1/2 is activated by a selective mechanism of Ca2+ entry (SOCE) in these cells, and suggest that ERK1/2 may contribute to events downstream of SOCE.
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Affiliation(s)
- Stephen P Soltoff
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Signal Transduction, Harvard Medical School, Boston, Massachussetts, USA.
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McCall AD, Nelson JW, Leigh NJ, Duffey ME, Lei P, Andreadis ST, Baker OJ. Growth factors polymerized within fibrin hydrogel promote amylase production in parotid cells. Tissue Eng Part A 2013; 19:2215-25. [PMID: 23594102 DOI: 10.1089/ten.tea.2012.0674] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Salivary gland cell differentiation has been a recurring challenge for researchers as primary salivary cells show a loss of phenotype in culture. Particularly, parotid cells show a marked decrease in amylase expression, the loss of tight junction organization and proper cell function. Previously, Matrigel has been used successfully as an extracellular matrix; however, it is not practical for in vivo applications as it is tumorigenic. An alternative method could rely on the use of fibrin hydrogel (FH), which has been used extensively in biomedical engineering applications ranging from cardiovascular tissue engineering to wound-healing experiments. Although several groups have examined the effects of a three-dimensional (3D) environment on salivary cell cultures, little is known about the effects of FH on salivary cell cultures. The current study developed a 3D cell culture model to support parotid gland cell differentiation using a combination of FH and growth factor-reduced Matrigel (GFR-MG). Furthermore, FH polymerized with a combination of EGF and IGF-1 induced formation of 3D spheroids capable of amylase expression and an agonist-induced increase in the intracellular Ca(2+) concentration ([Ca(2+)]i) in salivary cells. These studies represent an initial step toward the construction of an artificial salivary gland to restore salivary gland dysfunction. This is necessary to reduce xerostomia in patients with compromised salivary function.
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Affiliation(s)
- Andrew D McCall
- Department of Oral Biology, School of Dental Medicine, University at Buffalo-The State University of New York, Buffalo, NY 14214, 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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Nelson J, Manzella K, Baker OJ. Current cell models for bioengineering a salivary gland: a mini-review of emerging technologies. Oral Dis 2012; 19:236-44. [PMID: 22805753 PMCID: PMC3477256 DOI: 10.1111/j.1601-0825.2012.01958.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Saliva plays a major role in maintaining oral health. Patients afflicted with a decrease in saliva secretion (symptomatically, xerostomia) exhibit difficulty in chewing and swallowing foods, tooth decay, periodontal disease, and microbial infections. Despite recent improvements in treating xerostomia (e.g., saliva stimulants, saliva substitutes, and gene therapy), there is a need of more scientific advancements that can be clinically applied toward restoration of compromised salivary gland function. Here we provide a summary of the current salivary cell models that have been used to advance restorative treatments via development of an artificial salivary gland. These models represent initial steps toward clinical and translational research, to facilitate creation of clinically safe salivary glands. Further studies in salivary cell lines and primary cells are necessary to improve survival rates, cell differentiation, and secretory function. Additionally, the characterization of salivary progenitor and stem cell markers are necessary. Although these models are not fully characterized, their improvement may lead to the construction of an artificial salivary gland that is in high demand for improving the quality of life of many patients suffering from salivary secretory dysfunction.
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Affiliation(s)
- J Nelson
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, The State University of New York, Buffalo, NY, 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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Sequeira SJ, Soscia DA, Oztan B, Mosier AP, Jean-Gilles R, Gadre A, Cady NC, Yener B, Castracane J, Larsen M. The regulation of focal adhesion complex formation and salivary gland epithelial cell organization by nanofibrous PLGA scaffolds. Biomaterials 2012; 33:3175-86. [PMID: 22285464 DOI: 10.1016/j.biomaterials.2012.01.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 01/04/2012] [Indexed: 12/31/2022]
Abstract
Nanofiber scaffolds have been useful for engineering tissues derived from mesenchymal cells, but few studies have investigated their applicability for epithelial cell-derived tissues. In this study, we generated nanofiber (250 nm) or microfiber (1200 nm) scaffolds via electrospinning from the polymer, poly-l-lactic-co-glycolic acid (PLGA). Cell-scaffold contacts were visualized using fluorescent immunocytochemistry and laser scanning confocal microscopy. Focal adhesion (FA) proteins, such as phosphorylated FAK (Tyr397), paxillin (Tyr118), talin and vinculin were localized to FA complexes in adult cells grown on planar surfaces but were reduced and diffusely localized in cells grown on nanofiber surfaces, similar to the pattern observed in adult mouse salivary gland tissues. Significant differences in epithelial cell morphology and cell clustering were also observed and quantified, using image segmentation and computational cell-graph analyses. No statistically significant differences in scaffold stiffness between planar PLGA film controls compared to nanofibers scaffolds were detected using nanoindentation with atomic force microscopy, indicating that scaffold topography rather than mechanical properties accounts for changes in cell attachments and cell structure. Finally, PLGA nanofiber scaffolds could support the spontaneous self-organization and branching of dissociated embryonic salivary gland cells. Nanofiber scaffolds may therefore have applicability in the future for engineering an artificial salivary gland.
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Affiliation(s)
- Sharon J Sequeira
- Department of Biological Sciences, University at Albany, State University of New York, 1400 Washington Ave, LSRB 1086, Albany, NY 12222, 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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20
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Hedden L, Benes CH, Soltoff SP. P2X(7) receptor antagonists display agonist-like effects on cell signaling proteins. Biochim Biophys Acta Gen Subj 2011; 1810:532-42. [PMID: 21397667 DOI: 10.1016/j.bbagen.2011.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 02/14/2011] [Accepted: 03/07/2011] [Indexed: 11/17/2022]
Abstract
BACKGROUND The activation of various P2 receptors (P2R) by extracellular nucleotides promotes diverse cellular events, including the stimulation of cell signaling protein and increases in [Ca(2+)](i). We report that some agents that can block P2X(7)R receptors also promote diverse P2X(7)R-independent effects on cell signaling. METHODS We exposed native rat parotid acinar cells, salivary gland cell lines (Par-C10, HSY, HSG), and PC12 cells to suramin, DIDS (4,4'-diisothiocyano stilbene-2,2'-disulfonic acid), Cibacron Blue 3GA, Brilliant Blue G, and the P2X(7)R-selective antagonist A438079, and examined the activation/phosphorylation of ERK1/2, PKCδ, Src, CDCP1, and other signaling proteins. RESULTS With the exception of suramin, these agents blocked the phosphorylation of ERK1/2 by BzATP in rat parotid acinar cells; but higher concentrations of suramin blocked ATP-stimulated (45)Ca(2+) entry. Aside from A438079, these agents increased the phosphorylation of ERK1/2, Src, PKCδ, and other proteins (including Dok-1) within minutes in an agent- and cell type-specific manner in the absence of a P2X(7)R ligand. The stimulatory effect of these compounds on the tyrosine phosphorylation of CDCP1 and its Src-dependent association with PKCδ was blocked by knockdown of CDCP1, which also blocked Src and PKCδ phosphorylation. CONCLUSIONS Several agents used as P2X(7)R blockers promote the activation of various signaling proteins and thereby act more like receptor agonists than antagonists. GENERAL SIGNIFICANCE Some compounds used to block P2 receptors have complicated effects that may confound their use in blocking receptor activation and other biological processes for which they are employed, including their use as blockers of various ion transport proteins.
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Affiliation(s)
- Lee Hedden
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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21
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Baker OJ, Schulz DJ, Camden JM, Liao Z, Peterson TS, Seye CI, Petris MJ, Weisman GA. Rat parotid gland cell differentiation in three-dimensional culture. Tissue Eng Part C Methods 2011; 16:1135-44. [PMID: 20121592 DOI: 10.1089/ten.tec.2009.0438] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The use of polarized salivary gland cell monolayers has contributed to our understanding of salivary gland physiology. However, these cell models are not representative of glandular epithelium in vivo, and, therefore, are not ideal for investigating salivary epithelial functions. The current study has developed a three-dimensional (3D) cell culture model for rat Par-C10 parotid gland cells that forms differentiated acinar-like spheres on Matrigel. These 3D Par-C10 acinar-like spheres display characteristics similar to differentiated acini in salivary glands, including cell polarization, tight junction (TJ) formation required to maintain transepithelial potential difference, basolateral expression of aquaporin-3 and Na+/K+/2Cl- cotransporter-1, and responsiveness to the muscarinic receptor agonist carbachol that is decreased by the anion channel blocker diphenylamine-2-carboxylic acid or chloride replacement with gluconate. Incubation of the spheres in the hypertonic medium increased the expression level of the water channel aquaporin-5. Further, the proinflammatory cytokines tumor necrosis factor-alpha and interferon-gamma induced alterations in TJ integrity in the acinar-like spheres without affecting individual cell viability, suggesting that cytokines may affect salivary gland function by altering TJ integrity. Thus, 3D Par-C10 acinar-like spheres represent a novel in vitro model to study physiological and pathophysiological functions of differentiated acini.
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Affiliation(s)
- Olga J Baker
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, The State University of New York, Buffalo, New York 14214-3092, USA.
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22
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Soltoff SP, Asara JM, Hedden L. Regulation and identification of Na,K-ATPase alpha1 subunit phosphorylation in rat parotid acinar cells. J Biol Chem 2010; 285:36330-8. [PMID: 20841356 DOI: 10.1074/jbc.m110.136465] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The stimulation of fluid and electrolyte secretion in salivary cells results in ionic changes that promote rapid increases in the activity of the Na,K-ATPase. In many cell systems, there are conflicting findings concerning the regulation of the phosphorylation of the Na,K-ATPase α subunit, which is the catalytic moiety. Initially, we investigated the phosphorylation sites on the α1 subunit in native rat parotid acinar cells using tandem mass spectrometry and identified two new phosphorylation sites (Ser(222), Ser(407)), three sites (Ser(217), Tyr(260), Ser(47)) previously found from large scale proteomic screens, and two sites (Ser(23), Ser(16)) known to be phosphorylated by PKC. Subsequently, we used phospho-specific antibodies to examine the regulation of phosphorylation on Ser(23) and Ser(16) and measured changes in ERK phosphorylation in parallel. The G-protein-coupled muscarinic receptor mimetic carbachol, the phorbol ester phorbol 12-myristate 13-acetate, the Ca(2+) ionophore ionomycin, and the serine/threonine phosphatase inhibitor calyculin A increased Ser(23) α1 phosphorylation. Inhibition of classical PKC proteins blocked carbachol-stimulated Ser(23) α1 subunit phosphorylation but not ERK phosphorylation, which was blocked by an inhibitor of novel PKC proteins. The carbachol-initiated phosphorylation of Ser(23) α1 subunit was not modified by ERK or PKA activity. The Na,K-ATPase inhibitor ouabain reduced and enhanced the carbachol-promoted phosphorylation of Ser(23) and Ser(16), respectively, the latter because ouabain itself increased Ser(16) phosphorylation; thus, both sites display conformational-dependent phosphorylation changes. Ouabain-initiated phosphorylation of Ser(16) α1 was not blocked by PKC inhibitors, unlike carbachol- or phorbol 12-myristate 13-acetate-initiated phosphorylations, suggesting that this site was also a substrate for a kinase other than PKC.
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Affiliation(s)
- Stephen P Soltoff
- Division of Signal Transduction, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, USA.
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23
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Soltoff SP, Hedden L. Isoproterenol and cAMP block ERK phosphorylation and enhance [Ca2+]i increases and oxygen consumption by muscarinic receptor stimulation in rat parotid and submandibular acinar cells. J Biol Chem 2010; 285:13337-48. [PMID: 20207737 DOI: 10.1074/jbc.m110.112094] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Salivary glands are innervated by sympathetic and parasympathetic neurons, which release neurotransmitters that promote fluid secretion and exocytosis when they bind to muscarinic and beta-adrenergic receptors, respectively. Signaling pathways downstream of these receptors are mainly distinct, but there is cross-talk that affects receptor-dependent events. Here we report that the beta-adrenergic ligand isoproterenol blocks increases in extracellular signal-related kinase (ERK) phosphorylation, a protein kinase C-dependent event promoted by the muscarinic receptor ligand carbachol in freshly dispersed rat parotid acinar cells. The inhibitory action of isoproterenol was reproduced by cAMP stimuli (forskolin) and mimetics (dibutyryl-cAMP, 8-(4-chlorophenylthio)-cAMP), including one highly selective for protein kinase A (N(6)-benzoyl-cAMP). In contrast, Epac (exchange proteins directly activated by cAMP)-selective activators did not mimic the blockade of ERK by isoproterenol, suggesting that inhibition involved protein kinase A. Isoproterenol also blocked ERK downstream of phorbol 12-myristate 13-acetate and the P2X(7) and epidermal growth factor receptors. Isoproterenol and forskolin blocked MEK phosphorylation, reduced RAF phosphorylation on a stimulatory site (Ser-338), and increased RAF phosphorylation on an inhibitory site (Ser-259). Inhibitory effects on ERK were also observed in freshly dispersed rat submandibular acinar cells but not in three immortalized/cancer salivary cell lines (Par-C10, HSY, HSG), indicating significant differences between native cells and cell lines. Notably, in native parotid cells isoproterenol enhanced the carbachol-promoted increases in [Ca(2+)](i) and oxygen consumption, events that initiate and accompany, respectively, the stimulation of fluid secretion by muscarinic ligands. Thus, isoproterenol produces opposite effects on prominent events downstream of the muscarinic receptor second messengers diacylglycerol (decrease in ERK phosphorylation) and inositol trisphosphate (increase in [Ca(2+)](i) and fluid secretion).
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Affiliation(s)
- Stephen P Soltoff
- Division of Signal Transduction, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, USA.
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24
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Ratchford AM, Baker OJ, Camden JM, Rikka S, Petris MJ, Seye CI, Erb L, Weisman GA. P2Y2 nucleotide receptors mediate metalloprotease-dependent phosphorylation of epidermal growth factor receptor and ErbB3 in human salivary gland cells. J Biol Chem 2010; 285:7545-55. [PMID: 20064929 DOI: 10.1074/jbc.m109.078170] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The G protein-coupled receptor P2Y(2) nucleotide receptor (P2Y(2)R) has been shown to be up-regulated in a variety of tissues in response to stress or injury. Recent studies have suggested that P2Y(2)Rs may play a role in immune responses, wound healing, and tissue regeneration via their ability to activate multiple signaling pathways, including activation of growth factor receptors. Here, we demonstrate that in human salivary gland (HSG) cells, activation of the P2Y(2)R by its agonist induces phosphorylation of ERK1/2 via two distinct mechanisms, a rapid, protein kinase C-dependent pathway and a slower and prolonged, epidermal growth factor receptor (EGFR)-dependent pathway. The EGFR-dependent stimulation of UTP-induced ERK1/2 phosphorylation in HSG cells is inhibited by the adamalysin inhibitor tumor necrosis factor-alpha protease inhibitor or by small interfering RNA that selectively silences ADAM10 and ADAM17 expression, suggesting that ADAM metalloproteases are required for P2Y(2)R-mediated activation of the EGFR. G protein-coupled receptors have been shown to promote proteolytic release of EGFR ligands; however, neutralizing antibodies to known ligands of the EGFR did not inhibit UTP-induced EGFR phosphorylation. Immunoprecipitation experiments indicated that UTP causes association of the EGFR with another member of the EGF receptor family, ErbB3. Furthermore, stimulation of HSG cells with UTP induced phosphorylation of ErbB3, and silencing of ErbB3 expression inhibited UTP-induced phosphorylation of both ErbB3 and EGFR. UTP-induced phosphorylation of ErbB3 and EGFR was also inhibited by silencing the expression of the ErbB3 ligand neuregulin 1 (NRG1). These results suggest that P2Y(2)R activation in salivary gland cells promotes the formation of EGFR/ErbB3 heterodimers and metalloprotease-dependent neuregulin 1 release, resulting in the activation of both EGFR and ErbB3.
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Affiliation(s)
- Ann M Ratchford
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, Missouri 65211, USA
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Perry C, Baker OJ, Reyland ME, Grichtchenko II. PKC{alpha}{beta}{gamma}- and PKC{delta}-dependent endocytosis of NBCe1-A and NBCe1-B in salivary parotid acinar cells. Am J Physiol Cell Physiol 2009; 297:C1409-23. [PMID: 19783762 DOI: 10.1152/ajpcell.00028.2009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We examined membrane trafficking of NBCe1-A and NBCe1-B variants of the electrogenic Na(+)-HCO(3)(-) cotransporter (NBCe1) encoded by the SLC4A4 gene, using confocal fluorescent microscopy in rat parotid acinar cells (ParC5 and ParC10). We showed that yellow fluorescent protein (YFP)-tagged NBCe1-A and green fluorescent protein (GFP)-tagged NBCe1-B are colocalized with E-cadherin in the basolateral membrane (BLM) but not with the apical membrane marker zona occludens 1 (ZO-1). We inhibited constitutive recycling with monensin and W13 and detected that NBCe1-A and NBCe1-B accumulated in vesicles marked with the early endosomal marker early endosome antigen-1 (EEA1), with a parallel loss from the BLM. We observed that NBCe1-A and NBCe1-B undergo massive carbachol (CCh)-stimulated redistribution from the BLM into early endosomes. We showed that internalization of NBCe1-A and NBCe1-B was prevented by the general PKC inhibitor GF-109203X, the PKCalphabetagamma-specific inhibitor Gö-6976, and the PKCdelta-specific inhibitor rottlerin. We verified the involvement of PKCdelta by blocking CCh-induced internalization of NBCe1-A-cyan fluorescent protein (CFP) in cells transfected with dominant-negative kinase-dead (Lys376Arg) PKCdelta-GFP. Our data suggest that NBCe1-A and NBCe1-B undergo constitutive and CCh-stimulated endocytosis regulated by conventional PKCs (PKCalphabetagamma) and by novel PKCdelta in rat epithelial cells. To help develop a more complete model of the role of NBCe1 in parotid acinar cells we also investigated the initial phase of the secretory response to cholinergic agonist. In an Ussing chamber study we showed that inhibition of basolateral NBCe1 with 5-chloro-2,3-dihydro-3-(hydroxy-2-thienylmethylene)-2-oxo-1H-indole-1-carboxamide (tenidap) significantly decreases an initial phase of luminal anion secretion measured as a transient short-circuit current (I(sc)) across ParC10 cell monolayers. Using trafficking and functional data we propose a model that describes a physiological role of NBC in salivary acinar cell secretion.
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Affiliation(s)
- Clint Perry
- Department of Physiology and Biophysics, University of Colorado Denver, Aurora, 80045, USA
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Perry C, Quissell DO, Reyland ME, Grichtchenko II. Electrogenic NBCe1 (SLC4A4), but not electroneutral NBCn1 (SLC4A7), cotransporter undergoes cholinergic-stimulated endocytosis in salivary ParC5 cells. Am J Physiol Cell Physiol 2008; 295:C1385-98. [PMID: 18815229 DOI: 10.1152/ajpcell.00153.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cholinergic agonists are major stimuli for fluid secretion in parotid acinar cells. Saliva bicarbonate is essential for maintaining oral health. Electrogenic and electroneutral Na(+)-HCO(3)(-) cotransporters (NBCe1 and NBCn1) are abundant in parotid glands. We previously reported that angiotensin regulates NBCe1 by endocytosis in Xenopus oocytes. Here, we studied cholinergic regulation of NBCe1 and NBCn1 membrane trafficking by confocal fluorescent microscopy and surface biotinylation in parotid epithelial cells. NBCe1 and NBCn1 colocalized with E-cadherin monoclonal antibody at the basolateral membrane (BLM) in polarized ParC5 cells. Inhibition of constitutive recycling with the carboxylic ionophore monensin or the calmodulin antagonist W-13 caused NBCe1 to accumulate in early endosomes with a parallel loss from the BLM, suggesting that NBCe1 is constitutively endocytosed. Carbachol and PMA likewise caused redistribution of NBCe1 from BLM to early endosomes. The PKC inhibitor, GF-109203X, blocked this redistribution, indicating a role for PKC. In contrast, BLM NBCn1 was not downregulated in parotid acinar cells treated with constitutive recycling inhibitors, cholinergic stimulators, or PMA. We likewise demonstrate striking differences in regulation of membrane trafficking of NBCe1 vs. NBCn1 in resting and stimulated cells. We speculate that endocytosis of NBCe1, which coincides with the transition to a steady-state phase of stimulated fluid secretion, could be a part of acinar cell adjustment to a continuous secretory response. Stable association of NBCn1 at the membrane may facilitate constitutive uptake of HCO(3)(-) across the BLM, thus supporting HCO(3)(-) luminal secretion and/or maintaining acid-base homeostasis in stimulated cells.
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Affiliation(s)
- Clint Perry
- Univ. of Colorado and Denver Health Sciences Center, Dept. of Physiology and Biophysics, Mail Stop 8307, P.O. Box 6511, Aurora, CO 80045, USA
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Baker OJ, Camden JM, Redman RS, Jones JE, Seye CI, Erb L, Weisman GA. Proinflammatory cytokines tumor necrosis factor-alpha and interferon-gamma alter tight junction structure and function in the rat parotid gland Par-C10 cell line. Am J Physiol Cell Physiol 2008; 295:C1191-201. [PMID: 18768927 DOI: 10.1152/ajpcell.00144.2008] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Sjögren's syndrome (SS) is an autoimmune disorder characterized by inflammation and dysfunction of salivary glands, resulting in impaired secretory function. The production of the proinflammatory cytokines tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) is elevated in exocrine glands of patients with SS, although little is known about the effects of these cytokines on salivary epithelial cell functions necessary for saliva secretion, including tight junction (TJ) integrity and the establishment of transepithelial ion gradients. The present study demonstrates that chronic exposure of polarized rat parotid gland (Par-C10) epithelial cell monolayers to TNF-alpha and IFN-gamma decreases transepithelial resistance (TER) and anion secretion, as measured by changes in short-circuit current (I(sc)) induced by carbachol, a muscarinic cholinergic receptor agonist, or UTP, a P2Y(2) nucleotide receptor agonist. In contrast, TNF-alpha and IFN-gamma had no effect on agonist-induced increases in the intracellular calcium concentration [Ca(2+)](i) in Par-C10 cells. Furthermore, treatment of Par-C10 cell monolayers with TNF-alpha and IFN-gamma increased paracellular permeability to normally impermeant proteins, altered cell and TJ morphology, and downregulated the expression of the TJ protein, claudin-1, but not other TJ proteins expressed in Par-C10 cells. The decreases in TER, agonist-induced transepithelial anion secretion, and claudin-1 expression caused by TNF-alpha, but not IFN-gamma, were reversible by incubation of Par-C10 cell monolayers with cytokine-free medium for 24 h, indicating that IFN-gamma causes irreversible inhibition of cellular activities associated with fluid secretion in salivary glands. Our results suggest that cytokine production is an important contributor to secretory dysfunction in SS by disrupting TJ integrity of salivary epithelium.
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Affiliation(s)
- Olga J Baker
- Dept. of Biochemistry, Univ. of Missouri-Columbia, 540A Christopher S. Bond Life Sciences Center, Columbia, MO 65211, USA.
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Soltoff SP, Hedden L. Regulation of ERK1/2 by ouabain and Na-K-ATPase-dependent energy utilization and AMPK activation in parotid acinar cells. Am J Physiol Cell Physiol 2008; 295:C590-9. [PMID: 18632735 DOI: 10.1152/ajpcell.00140.2008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We previously found that the phosphorylation of ERK1/2 by submaximal concentrations of the muscarinic receptor ligand carbachol was potentiated in rat parotid acinar cells exposed to ouabain, a cardiac glycoside that inhibits the Na-K-ATPase. We now report that this signaling phenomenon involves the prevention of negative regulation of extracellular signal-regulated kinase-1/2 (ERK1/2) that is normally mediated by AMP-activated protein kinase (AMPK). Carbachol increases the turnover of the ATP-consuming Na-K-ATPase, reducing intracellular ATP and promoting the phosphorylation/activation of the energy sensor AMPK. Ouabain blocks the reduction in ATP and subsequent AMPK phosphorylation, which is regulated by the AMP-to-ATP ratio. The ouabain-promoted enhancement of ERK1/2 phosphorylation was not reproduced in Par-C10 cells, an immortalized rat parotid cell line that did not respond to carbachol with an ATP reduction and that employs an upstream AMPK kinase (Ca(2+)/calmodulin-dependent protein kinase kinase, CaMKK) different from that (LKB1) in native cells. In native parotid cells, inhibitory effects of AMPK on ERK1/2 signaling were examined by activating AMPK with 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR), which is converted to an AMP mimetic but does not alter parotid ATP levels. AICAR-treated cells display increases in AMPK phosphorylation and a reduced phosphorylation of ERK1/2 subsequent to activation of muscarinic and P2X(7) receptors, which promote increases in Na-K-ATPase turnover, but not upon epidermal growth factor receptor activation. These results suggest that carbachol-initiated AMPK activation can produce a negative feedback on ERK1/2 signaling in response to submaximal muscarinic receptor activation and that increases in fluid secretion can modulate receptor-initiated signaling events indirectly by producing ion transport-dependent decreases in ATP.
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Affiliation(s)
- Stephen P Soltoff
- Division of Signal Transduction, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02111, USA.
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Nathanson NM. Synthesis, trafficking, and localization of muscarinic acetylcholine receptors. Pharmacol Ther 2008; 119:33-43. [PMID: 18558434 DOI: 10.1016/j.pharmthera.2008.04.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 04/28/2008] [Indexed: 12/27/2022]
Abstract
Muscarinic acetylcholine receptors are members of the G-protein coupled receptor superfamily that are expressed in and regulate the function of neurons, cardiac and smooth muscle, glands, and many other cell types and tissues. The correct trafficking of membrane proteins to the cell surface and their subsequent localization at appropriate sites in polarized cells are required for normal cellular signaling and physiological responses. This review will summarize work on the synthesis and trafficking of muscarinic receptors to the plasma membrane and their localization at the cell surface.
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Affiliation(s)
- Neil M Nathanson
- Department of Pharmacology, School of Medicine, University of Washington, Box 357750, Seattle, WA 98195-7750, USA.
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Baggaley E, McLarnon S, Demeter I, Varga G, Bruce JIE. Differential regulation of the apical plasma membrane Ca(2+) -ATPase by protein kinase A in parotid acinar cells. J Biol Chem 2007; 282:37678-93. [PMID: 17938178 DOI: 10.1074/jbc.m703416200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cross-talk between intracellular calcium ([Ca(2+)](i)) signaling and cAMP defines the specificity of stimulus-response coupling in a variety of cells. Previous studies showed that protein kinase A (PKA) potentiates and phosphorylates the plasma membrane Ca(2+)-ATPase (PMCA) in a Ca(2+)-dependent manner in parotid acinar cells (Bruce, J. I. E., Yule, D. I., and Shuttleworth, T. J. (2002) J. Biol. Chem. 277, 48172-48181). The aim of this study was to further investigate the spatial regulation of [Ca(2+)](i) clearance in parotid acinar cells. Par-C10 cells were used to functionally isolate the apical and basolateral PMCA activity by applying La(3+) to the opposite side to inhibit the PMCA. Activation of PKA (using forskolin) differentially potentiated apical [Ca(2+)](i) clearance in mouse parotid acinar cells and apical PMCA activity in Par-C10 cells. Immunofluorescence of parotid tissue slices revealed that PMCA1 was distributed throughout the plasma membrane, PMCA2 was localized to the basolateral membrane, and PMCA4 was localized to the apical membrane of parotid acinar cells. However, in situ phosphorylation assays demonstrated that PMCA1 was the only isoform phosphorylated by PKA following stimulation. Similarly, immunofluorescence of acutely isolated parotid acinar cells showed that the regulatory subunit of PKA (RIIbeta) translocated to the apical region following stimulation. These data suggest that PKA-mediated phosphorylation of PMCA1 differentially regulates [Ca(2+)](i) clearance in the apical region of parotid acinar cells because of a dynamic translocation of PKA. Such tight spatial regulation of Ca(2+) efflux is likely important for the fine-tuning of Ca(2+)-dependent effectors close to the apical membrane important for the regulation of fluid secretion and exocytosis.
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Affiliation(s)
- Erin Baggaley
- Faculty of Life Sciences, the University of Manchester, Manchester, UK
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31
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Baker OJ, Camden JM, Rome DE, Seye CI, Weisman GA. P2Y2 nucleotide receptor activation up-regulates vascular cell adhesion molecule-1 [corrected] expression and enhances lymphocyte adherence to a human submandibular gland cell line. Mol Immunol 2007; 45:65-75. [PMID: 17599409 PMCID: PMC2064040 DOI: 10.1016/j.molimm.2007.05.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Accepted: 05/13/2007] [Indexed: 12/13/2022]
Abstract
Sjögren's syndrome (SS) is a chronic inflammatory autoimmune disease that causes salivary and lacrimal gland tissue destruction resulting in impaired secretory function. Although lymphocytic infiltration of salivary epithelium is associated with SS, the mechanisms involved have not been adequately elucidated. Our previous studies have shown that the G protein-coupled P2Y2 nucleotide receptor (P2Y2R) is up-regulated in response to damage or stress of salivary gland epithelium, and in salivary glands of the NOD.B10 mouse model of SS-like autoimmune exocrinopathy. Additionally, we have shown that P2Y2R activation up-regulates vascular cell adhesion molecule-1 (VCAM-1) expression in endothelial cells leading to the binding of monocytes. The present study demonstrates that activation of the P2Y2R in dispersed cell aggregates from rat submandibular gland (SMG) and in human submandibular gland ductal cells (HSG) up-regulates the expression of VCAM-1. Furthermore, P2Y2R activation mediated the up-regulation of VCAM-1 expression in HSG cells leading to increased adherence of lymphocytic cells. Inhibitors of EGFR phosphorylation and metalloprotease activity abolished P2Y2R-mediated VCAM-1 expression and decreased lymphocyte binding to HSG cells. Moreover, silencing of EGFR expression abolished UTP-induced VCAM-1 up-regulation in HSG cells. These results suggest that P2Y2R activation in salivary gland cells increases the EGFR-dependent expression of VCAM-1 and the binding of lymphocytes, a pathway relevant to inflammation associated with SS.
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Affiliation(s)
- Olga J Baker
- Department of Biochemistry, University of Missouri-Columbia, 540E Christopher S. Bond Life Sciences Center, 1201 Rollins Road, Columbia, MO 65211-0001, USA
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Camden JM, Schrader AM, Camden RE, González FA, Erb L, Seye CI, Weisman GA. P2Y2 nucleotide receptors enhance alpha-secretase-dependent amyloid precursor protein processing. J Biol Chem 2005; 280:18696-702. [PMID: 15778502 DOI: 10.1074/jbc.m500219200] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The amyloid precursor protein (APP) is proteolytically processed by beta- and gamma-secretases to release amyloid beta, the main component in senile plaques found in the brains of patients with Alzheimer disease. Alternatively, APP can be cleaved within the amyloid beta domain by alpha-secretase releasing the non-amyloidogenic product sAPP alpha, which has been shown to have neuroprotective properties. Several G protein-coupled receptors are known to activate alpha-secretase-dependent processing of APP; however, the role of G protein-coupled nucleotide receptors in APP processing has not been investigated. Here it is demonstrated that activation of the G protein-coupled P2Y2 receptor (P2Y2R) subtype expressed in human 1321N1 astrocytoma cells enhanced the release of sAPP alpha in a time- and dose-dependent manner. P2Y2 R-mediated sAPP alpha release was dependent on extracellular calcium but was not affected by 1,2-bis(2-aminophenoxy)ethane-N,N,N,-trimethylammonium salt, an intracellular calcium chelator, indicating that P2Y2R-stimulated intracellular calcium mobilization was not involved. Inhibition of protein kinase C (PKC) with GF109203 or by PKC down-regulation with phorbol ester pre-treatment had no effect on UTP-stimulated sAPP alpha release, indicating a PKC-independent mechanism. U0126, an inhibitor of the mitogen-activated protein kinase pathway, partially inhibited sAPPalpha release by UTP, whereas inhibitors of Src-dependent epidermal growth factor receptor transactivation by P2Y2Rs had no effect. The metalloprotease inhibitors phenanthroline and TAPI-2 and the furin inhibitor decanoyl-Arg-Val-Lys-Arg-chloromethylketone also diminished UTP-induced sAPP alpha release. Furthermore, small interfering RNA silencing of an endogenous adamalysin, ADAM10 or ADAM17/TACE, partially suppressed P2Y2R-activated sAPP alpha release, whereas treatment of cells with both ADAM10 and ADAM17/TACE small interfering RNAs completely abolished UTP-activated sAPP alpha release. These results may contribute to an understanding of the non-amyloidogenic processing of APP.
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Affiliation(s)
- Jean M Camden
- Department of Biochemistry, University of Missouri-Columbia, Columbia, Missouri 65211-7310, USA
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Burnstock G, Knight GE. Cellular Distribution and Functions of P2 Receptor Subtypes in Different Systems. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 240:31-304. [PMID: 15548415 DOI: 10.1016/s0074-7696(04)40002-3] [Citation(s) in RCA: 573] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review is aimed at providing readers with a comprehensive reference article about the distribution and function of P2 receptors in all the organs, tissues, and cells in the body. Each section provides an account of the early history of purinergic signaling in the organ?cell up to 1994, then summarizes subsequent evidence for the presence of P2X and P2Y receptor subtype mRNA and proteins as well as functional data, all fully referenced. A section is included describing the plasticity of expression of P2 receptors during development and aging as well as in various pathophysiological conditions. Finally, there is some discussion of possible future developments in the purinergic signaling field.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Institute, Royal Free and University College Medical School, London NW3 2PF, United Kingdom
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Liu X, Mörk AC, Sun X, Castro R, Martinez JR, Zhang GH. Regulation of Ca(2+) signals in a parotid cell line Par-C5. Arch Oral Biol 2001; 46:1141-9. [PMID: 11684033 DOI: 10.1016/s0003-9969(01)00074-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Ca(2+) signaling system in an established immortalized rat parotid acinar cell line, Par-C5, was examined using the Ca(2+)-sensitive fluorescent indicator fura-2 and by measuring inositol 1,4,5-trisphosphate (IP(3)) formation. Agonist-induced increase in intracellular Ca(2+) ([Ca(2+)](i)) by mobilization of intracellular stores and influx across the cell membrane was stimulated by acetylcholine (ACh) and ATP, whereas noradrenaline-(NA)-induced a small [Ca(2+)](i) increase mediated primarily by release from intracellular Ca(2+) stores. [Ca(2+)](i) increase by ACh and ATP was mediated through the phosphoinositide signal pathway since both agonists significantly increased 1,4,5-IP(3) formation and Ca(2+) mobilization was abolished by the phospholipase C inhibitor U73122. In Ca(2+)-free medium, ACh or ATP discharged the IP(3)-sensitive Ca(2+) store and essentially abolished subsequent [Ca(2+)](i) response to thapsigargin (TG). Exposure to ionomycin and monensin after TG induced a further mobilization of Ca(2+), suggesting IP(3)-insensitive stores are present. Furthermore, depletion of IP(3)-sensitive Ca(2+) stores by TG, ACh and ATP enhanced plasmalemmal Ca(2+)-entry pathways. Exposure to tumor necrosis factor-alpha (TNF-alpha), a cytokine associated with lymphocyte invasion of salivary epithelial cells in autoimmune disorders, significantly reduced ACh-stimulated Ca(2+) mobilization. TNF-alpha inhibitory effect on Ca(2+) mobilization was not directly due to an interaction on muscarinic receptors since ACh-induced 1,4,5-IP(3) formation was not altered. These results in the Par-C5 cell line indicate 1) [Ca(2+)](i) is regulated by muscarinic and P2Y-nucleotide receptors and partly by alpha(1)-adrenergic receptors; 2) IP(3)-sensitive and -insensitive Ca(2+) stores exist; 3) Ca(2+) influx activated by ACh, ATP or TG is mediated by the store-operated Ca(2+) entry pathway; and 4) muscarinic agonist-stimulated Ca(2+) mobilization is altered by the cytokine TNF-alpha.
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Affiliation(s)
- X Liu
- Secretory Cell Physiology Laboratory, Department of Pediatrics, University of Texas Health Center, Mail Code 7827, 7703 Floyd Curl Dr., San Antonio, TX 78229-3900, USA
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Liu XB, Sun X, Mörk AC, Dodds MW, Martinez JR, Zhang GH. Characterization of the calcium signaling system in the submandibular cell line SMG-C6. PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE. SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE (NEW YORK, N.Y.) 2000. [PMID: 11082216 DOI: 10.1046/j.1525-1373.2000.22527.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Establishment of salivary cell lines retaining normal morphological and physiological characteristics is important in the investigation of salivary cell function. A submandibular gland cell line, SMG-C6, has recently been established. In the present study, we characterized the phosphoinositide (PI)-Ca2+ signaling system in this cell line. Inositol 1,4,5-trisphosphate(1,4,5-IP3) formation, as well as Ca2+ storage, release, and influx in response to muscarinic, alpha1-adrenergic, P2Y-nucleotide, and cytokine receptor agonists were determined. Ca2+ release from intracellular stores was strongly stimulated by acetylcholine (ACh) and ATP, but not by norepinephrine (NA), epidermal growth factor (EGF), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNFalpha). Consistently, 1, 4,5-IP3 formation was dramatically stimulated by ACh and ATP. ACh-stimulated cytosolic free Ca2+ concentration [Ca2+]i increase was inhibited by ryanodine, suggesting that the Ca2+-induced Ca2+ release mechanism is involved in the ACh-elicited Ca2+ release process. Furthermore, ACh and ATP partially discharged the IP3-sensitive Ca2+ store, and a subsequent exposure to thapsigargin (TG) induced further [Ca2+]i increase. However, exposure to TG depleted the store and a subsequent stimulation with ACh or ATP did not induce further [Ca2+]i increase, suggesting that ACh and ATP discharge the same storage site sensitive to TG. As in freshly isolated submandibular acinar cells, exposure to ionomycin and monensin following ACh or TG induced further [Ca2+]i increase, suggesting that IP3-insensitive stores exist in SMG-C6 cells. Ca2+ influx was activated by ACh, ATP, or TG, and was significantly inhibited by La3+, suggesting the involvement of store-operated Ca2+ entry (SOCE) pathway. These results indicate that in SMG-C6 cells: (i) Ca2+ release is triggered by muscarinic and P2Y-nucleotide receptor agonists through formation of IP3; (ii) both the IP3-sensitive and -insensitive Ca2+ stores are present; and (iii) Ca2+ influx is mediated by the store-operated Ca2+ entry pathway. We conclude that Ca2+ regulation in SMG-C6 cells is similar to that in freshly isolated SMG acinar cells; therefore, this cell line represents an excellent SMG cell model in terms of intracellular Ca2+ signaling.
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Affiliation(s)
- X B Liu
- Secretory Cell Physiology Laboratory, Department of Pediatrics, University of Texas Health Science Center, San Antonio, Texas 78229-3900, USA
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Castro R, Barlow-Walden L, Woodson T, Kerecman JD, Zhang GH, Martinez JR. Ion transport in an immortalized rat submandibular cell line SMG-C6. PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE. SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE (NEW YORK, N.Y.) 2000. [PMID: 10998197 DOI: 10.1046/j.1525-1373.2000.22505.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The immortalized rat submandibular epithelial cell line, SMG-C6, cultured on porous tissue culture supports, forms polarized, tight-junction epithelia facilitating bioelectric characterization in Ussing chambers. The SMG-C6 epithelia generated transepithelial resistances of 956+/-84Omega.cm2 and potential differences (PD) of -16.9 +/- 1.5mV (apical surface negative) with a basal short-circuit current (Isc) of 23.9 +/- 1.7 microA/cm2 (n = 69). P2 nucleotide receptor agonists, ATP or UTP, applied apically or basolaterally induced a transient increase in Isc, followed by a sustained decreased below baseline value. The peak DeltaIsc increase was partly sensitive to Cl- and K+ channel inhibitors, DPC, glibenclamide, and tetraethylammonium (TEA) and was completely abolished following Ca2+ chelation with BAPTA or bilateral substitution of gluconate for Cl-. The major component of basal Isc was sensitive to apical Na+ replacement or amiloride (half-maximal inhibitory concentration 392 nM). Following pretreatment with amiloride, ATP induced a significantly greater Isc; however, the poststimulatory decline was abolished, suggesting an ATP-induced inhibition of amiloride-sensitive Na+ transport. Consistent with the ion transport properties found in Ussing chambers, SMG-C6 cells express the rat epithelial Na+ channel alpha-subunit (alpha-rENaC). Thus, cultured SMG-C6 cells produce tight polarized epithelia on permeable support with stimulated Cl- secretory conductance and an inward Isc accounted for by amiloride-sensitive Na+ absorption.
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Affiliation(s)
- R Castro
- Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78284-7812, USA.
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Ahn JS, Camden JM, Schrader AM, Redman RS, Turner JT. Reversible regulation of P2Y(2) nucleotide receptor expression in the duct-ligated rat submandibular gland. Am J Physiol Cell Physiol 2000; 279:C286-94. [PMID: 10912994 DOI: 10.1152/ajpcell.2000.279.2.c286] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ligation of the main excretory duct of the rat submandibular gland (SMG) produces a pronounced atrophy that is reversed upon ligature removal. Based on previous studies by our group and others suggesting that P2Y(2) nucleotide receptors are upregulated in response to tissue damage, we hypothesized that P2Y(2) receptor activity and mRNA levels would increase after duct ligation and return to control levels after ligature removal. Our results support this hypothesis. Intracellular Ca(2+) mobilization in response to the P2Y(2) receptor agonist UTP in SMG cells was increased significantly after ligation periods of 1.5 to 7 days, whereas no significant response was observed in the contralateral, nonligated gland. P2Y(2) receptor mRNA, as measured by semiquantitative RT-PCR, increased about 15-fold after 3 days of ligation. These increases reverted to control levels by 14 days after ligature removal. In situ hybridization revealed that the changes in P2Y(2) receptor mRNA abundance occurred mostly in acinar cells, which also were more adversely affected by ligation, including an increase in the appearance of apoptotic bodies. These findings support the idea that P2Y(2) receptor upregulation may be an important component of the response to injury in SMG and that recovery of normal physiological function may signal a decreased requirement for P2Y(2) receptors.
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Affiliation(s)
- J S Ahn
- Department of Pharmacology, School of Medicine, University of Missouri, Columbia 65212, USA
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Turner JT, Landon LA, Gibbons SJ, Talamo BR. Salivary gland P2 nucleotide receptors. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 2000; 10:210-24. [PMID: 10759423 DOI: 10.1177/10454411990100020701] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effects of ATP on salivary glands have been recognized since 1982. Functional and pharmacological studies of the P2 nucleotide receptors that mediate the effects of ATP and other extracellular nucleotides have been supported by the cloning of receptor cDNAs, by the expression of the receptor proteins, and by the identification in salivary gland cells of multiple P2 receptor subtypes. Currently, there is evidence obtained from pharmacological and molecular biology approaches for the expression in salivary gland of two P2X ligand-gated ion channels, P2Z/P2X7 and P2X4, and two P2Y G protein-coupled receptors, P2Y1 and P2Y2. Activation of each of these receptor subtypes increases intracellular Ca2+, a second messenger with a key role in the regulation of salivary gland secretion. Through Ca2+ regulation and other mechanisms, P2 receptors appear to regulate salivary cell volume, ion and protein secretion, and increased permeability to small molecules that may be involved in cytotoxicity. Some localization of the various salivary P2 receptor subtypes to specific cells and membrane subdomains has been reported, along with evidence for the co-expression of multiple P2 receptor subtypes within specific salivary acinar or duct cells. However, additional studies in vivo and with intact organ preparations are required to define clearly the roles the various P2 receptor subtypes play in salivary gland physiology and pathology. Opportunities for eventual utilization of these receptors as pharmacotherapeutic targets in diseases involving salivary gland dysfunction appear promising.
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Affiliation(s)
- J T Turner
- Department of Pharmacology, University of Missouri-Columbia School of Medicine, 65212, USA
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Abstract
The inhibitory profile of several known and suspected ecto-ATPase inhibitors was compared on ecto-ATPase activity in rat parotid plasma membranes. Those chemicals with high IC50 (above 130 microM) were the nucleotides alpha,beta-methylene ATP, beta,gamma-methylene ATP, 2-methylthio ATP, inosine triphosphate, 5'-p-fluorosulphonylbenzoyladenosine, the sulphonates, 1-amino-2-naphthol-4-sulphonic acid, Coomassie brilliant blue G, and the stilbene disulphonates, DIDS and SITS. Those agents with low IC50 were: Coomassie brilliant blue R (114 microM), ATPgammaS (49 microM), suramin (72 microM) and Reactive blue 2 (28 microM). The last three inhibitors have similar potencies as inhibitors of ATP hydrolysis by whole parotid acinar cells. ARL67156, a selective inhibitor of ecto-ATPase, had an IC50 of approx. 120 microM. Suramin displayed non-competitive inhibition of ecto-ATPase whereas the inhibitory effects of ATPgammaS and Reactive blue 2 were curvilinear on Dixon plots. These results define the effects of various agents on ecto-ATPase in an exocrine tissue that has been shown to respond to extracellular ATP.
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Affiliation(s)
- F J Dowd
- Department of Pharmacology, Creighton University Medical School, Omaha, NE 68178, USA.
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Clarke LL, Harline MC, Otero MA, Glover GG, Garrad RC, Krugh B, Walker NM, González FA, Turner JT, Weisman GA. Desensitization of P2Y2 receptor-activated transepithelial anion secretion. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:C777-87. [PMID: 10199807 DOI: 10.1152/ajpcell.1999.276.4.c777] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Desensitization of P2Y2 receptor-activated anion secretion may limit the usefulness of extracellular nucleotides in secretagogue therapy of epithelial diseases, e.g., cystic fibrosis (CF). To investigate the desensitization process for endogenous P2Y2 receptors, freshly excised or cultured murine gallbladder epithelia (MGEP) were mounted in Ussing chambers to measure short-circuit current (Isc), an index of electrogenic anion secretion. Luminal treatment with nucleotide receptor agonists increased the Isc with a potency profile of ATP = UTP > 2-methylthioATP >> alpha,beta-methylene-ATP. RT-PCR revealed the expression of P2Y2 receptor mRNA in the MGEP cells. The desensitization of anion secretion required a 10-min preincubation with the P2Y2 receptor agonist UTP and increased in a concentration-dependent manner (IC50 approximately 10(-6) M). Approximately 40% of the anion secretory response was unaffected by maximal desensitizing concentrations of UTP. Recovery from UTP-induced desensitization was rapid (<10 min) at preincubation concentrations less than the EC50 (1.9 x 10(-6) M) but required progressively longer time periods at greater concentrations. UTP-induced total inositol phosphate production and intracellular Ca2+ mobilization desensitized with a concentration dependence similar to that of anion secretion. In contrast, maximal anion secretion induced by Ca2+ ionophore ionomycin was unaffected by preincubation with a desensitizing concentration of UTP. It was concluded that 1) desensitization of transepithelial anion secretion stimulated by the P2Y2 receptor agonist UTP is time and concentration dependent; 2) recovery from desensitization is prolonged (>90 min) at UTP concentrations >10(-5) M; and 3) UTP-induced desensitization occurs before the operation of the anion secretory mechanism.
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Affiliation(s)
- L L Clarke
- Dalton Cardiovascular Research Center and Department of Veterinary Biomedical Sciences, University of Missouri-Columbia, Columbia, Missouri 65211, USA.
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