1
|
Mironov AA, Beznoussenko GV. The Regulated Secretion and Models of Intracellular Transport: The Goblet Cell as an Example. Int J Mol Sci 2023; 24:ijms24119560. [PMID: 37298509 DOI: 10.3390/ijms24119560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/24/2023] [Accepted: 05/27/2023] [Indexed: 06/12/2023] Open
Abstract
Transport models are extremely important to map thousands of proteins and their interactions inside a cell. The transport pathways of luminal and at least initially soluble secretory proteins synthesized in the endoplasmic reticulum can be divided into two groups: the so-called constitutive secretory pathway and regulated secretion (RS) pathway, in which the RS proteins pass through the Golgi complex and are accumulated into storage/secretion granules (SGs). Their contents are released when stimuli trigger the fusion of SGs with the plasma membrane (PM). In specialized exocrine, endocrine, and nerve cells, the RS proteins pass through the baso-lateral plasmalemma. In polarized cells, the RS proteins secrete through the apical PM. This exocytosis of the RS proteins increases in response to external stimuli. Here, we analyze RS in goblet cells to try to understand the transport model that can be used for the explanation of the literature data related to the intracellular transport of their mucins.
Collapse
Affiliation(s)
- Alexander A Mironov
- Department of Cell Biology, IFOM ETS-The AIRC Institute of Molecular Oncology, Via Adamello, 16, 20139 Milan, Italy
| | - Galina V Beznoussenko
- Department of Cell Biology, IFOM ETS-The AIRC Institute of Molecular Oncology, Via Adamello, 16, 20139 Milan, Italy
| |
Collapse
|
2
|
Isola M, Ekström J, Isola R, Loy F. Melatonin release by exocytosis in the rat parotid gland. J Anat 2019; 234:338-345. [PMID: 30536666 PMCID: PMC6365479 DOI: 10.1111/joa.12921] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2018] [Indexed: 12/23/2022] Open
Abstract
Several beneficial effects on oral health are ascribed to melatonin. Due to its lipophilic nature, non-protein-bound circulating melatonin is usually thought to enter the saliva by passive diffusion through salivary acinar gland cells. Recently, however, using transmission electron microscopy (TEM), melatonin was found in acinar secretory granules of human salivary glands. To test the hypothesis that granular located melatonin is actively discharged into the saliva by exocytosis, i.e. contrary to the general belief, the β-adrenergic receptor agonist isoprenaline, which causes the degranulation of acinar parotid serous cells, was administered to anaesthetised rats. Sixty minutes after an intravenous bolus injection of isoprenaline (5 mg kg-1 ), the right parotid gland was removed; pre-administration, the left control gland had been removed. Samples were processed to demonstrate melatonin reactivity using the immunogold staining method. Morphometric assessment was made using TEM. Gold particles labelling melatonin appeared to be preferentially associated with secretory granules, occurring in their matrix and at membrane level but, notably, it was also associated with vesicles, mitochondria and nuclei. Twenty-six per cent of the total granular population (per 100 μm2 per cell area) displayed melatonin labelling in the matrix; three-quarters of this fraction disappeared (P < 0.01) in response to isoprenaline, and melatonin reactivity appeared in dilated lumina. Thus, evidence is provided of an alternative route for melatonin to reach the gland lumen and the oral cavity by active release through exocytosis, a process which is under the influence of parasympathetic and sympathetic nervous activity and is the final event along the so-called regulated secretory pathway. During its stay in granules, anti-oxidant melatonin may protect their protein/peptide constituents from damage.
Collapse
Affiliation(s)
- Michela Isola
- Department of Biomedical SciencesDivision of CytomorphologyUniversity of CagliariCagliariItaly
| | - Jörgen Ekström
- Department of Biomedical SciencesDivision of CytomorphologyUniversity of CagliariCagliariItaly
- Institute of Neuroscience and PhysiologyDepartment of PharmacologyThe Sahlgrenska Academy at the University of GothenburgGothenburgSweden
| | - Raffaella Isola
- Department of Biomedical SciencesDivision of CytomorphologyUniversity of CagliariCagliariItaly
| | - Francesco Loy
- Department of Biomedical SciencesDivision of CytomorphologyUniversity of CagliariCagliariItaly
| |
Collapse
|
3
|
Dufurrena Q, Bäck N, Mains R, Hodgson L, Tanowitz H, Mandela P, Eipper B, Kuliawat R. Kalirin/Trio Rho GDP/GTP exchange factors regulate proinsulin and insulin secretion. J Mol Endocrinol 2018; 62:JME-18-0048.R2. [PMID: 30407917 PMCID: PMC6494717 DOI: 10.1530/jme-18-0048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 11/05/2018] [Indexed: 12/31/2022]
Abstract
Key features for progression to pancreatic β-cell failure and disease are loss of glucose responsiveness and an increased ratio of secreted proinsulin to insulin. Proinsulin and insulin are stored in secretory granules (SGs) and the fine-tuning of hormone output requires signal mediated recruitment of select SG populations according to intracellular location and age. The GTPase Rac1 coordinates multiple signaling pathways that specify SG release and Rac1 activity is controlled in part by GDP/GTP exchange factors (GEFs). To explore the function of two large multidomain GEFs, Kalirin and Trio in β-cells, we manipulated their Rac1-specific GEF1 domain activity by using small molecule inhibitors and by genetically ablating Kalirin. We examined age related secretory granule behavior employing radiolabeling protocols. Loss of Kalirin/Trio function attenuated radioactive proinsulin release by reducing constitutive-like secretion and exocytosis of 2-hour old granules. At later chase times or at steady state, Kalirin/Trio manipulations decreased glucose stimulated insulin output. Finally, use of a Rac1 FRET biosensor with cultured β-cell lines, demonstrated that Kalirin/Trio GEF1 activity was required for normal rearrangement of Rac1 to the plasma membrane in response to glucose. Rac1 activation can be evoked by both glucose metabolism and signaling through the incretin glucagon-like peptide 1 (GLP-1) receptor. GLP-1 addition restored Rac1 localization/activity and insulin secretion in the absence of Kalirin, thereby assigning Kalirin's participation to stimulatory glucose signaling.
Collapse
Affiliation(s)
- Quinn Dufurrena
- Department of Medicine, Stony Brook University School of Medicine, Stony Brook, NY
| | - Nils Bäck
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Richard Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT
| | - Louis Hodgson
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY
| | - Herbert Tanowitz
- Departments of Pathology, Medicine, Albert Einstein College of Medicine, Bronx, NY
| | | | - Betty Eipper
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT
| | - Regina Kuliawat
- Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY
| |
Collapse
|
4
|
Isola M, Lilliu MA, Loy F, Isola R. Diabetic Status Influences the Storage of Melatonin in Human Salivary Glands. Anat Rec (Hoboken) 2017; 301:711-716. [PMID: 29236363 DOI: 10.1002/ar.23750] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/18/2017] [Accepted: 11/07/2017] [Indexed: 01/29/2023]
Abstract
Recently we reported on the detailed localization of melatonin (and its receptors) in human salivary glands, revealing that serous cells are able to store and secrete melatonin into saliva. Since we found that type 2 diabetic patients display reduced melatonin content in saliva, our next step was to examine the presence of melatonin in salivary glands removed from type 2 diabetic subjects. The resulting data were compared with those previously obtained by identical procedures in non-diabetics, to establish if the diabetic status may affect melatonin distribution. Bioptic samples of diabetic parotid and submandibular glands were fixed, dehydrated, embedded in Epon Resin and processed to demonstrate melatonin reactivity by the immunogold staining method. The labeling density (expressed as the number of gold particles per μm2 /granule) and the percentage of melatonin-positive granules were assessed in diabetic samples. These values were compared with those in non-diabetic samples and differences were evaluated. In parotid and submandibular diabetic glands the reactivity for melatonin was specifically associated with secretory granules and small vesicles in serous cells. Melatonin reactivity was higher in parotid than in submandibular glands. Our data were in line with those obtained in our previous study on non-diabetic glands. Diabetic salivary glands showed a higher labeling density and a lower number of melatonin-positive granules compared to non-diabetic glands. Taken together, these data might explain the decreased salivary melatonin content and the associated oral problems observed in diabetics. Anat Rec, 301:711-716, 2018. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Michela Isola
- Department of Biomedical Sciences, University of Cagliari, Italy
| | | | - Francesco Loy
- Department of Biomedical Sciences, University of Cagliari, Italy
| | - Raffaella Isola
- Department of Biomedical Sciences, University of Cagliari, Italy
| |
Collapse
|
5
|
The small GTPase, Rab27, and its effectors and regulators participate in granule exocytosis by parotid acinar cells. J Oral Biosci 2017. [DOI: 10.1016/j.job.2016.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
6
|
Xiang B, Zhang Y, Li YM, Zhang K, Zhang YY, Wu LL, Yu GY. Effects of Phenylephrine on Transplanted Submandibular Gland. J Dent Res 2016; 85:1106-11. [PMID: 17122163 DOI: 10.1177/154405910608501208] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Autotransplantation of the submandibular gland is a potential treatment for severe kerato-conjunctivitis sicca. However, one of the major barriers to this procedure is that secretions from the transplanted gland decrease shortly after the operation, which may lead to obstruction of Wharton’s duct, or even to transplantation failure. Using a rabbit model, we investigated whether phenylephrine could improve the secretion from the transplanted gland. We found that phenylephrine treatment significantly reversed the decrease in salivary secretion after transplantation, enhanced the expressions of α1A-, α1B-, and α1D-adrenoceptor mRNA, and ameliorated atrophy of acinar cells. Furthermore, phenylephrine also induced translocation of aquaporin-5 from the cytoplasm to the apical membrane, and increased the levels of phospho-ERK1/2, ERK1/2, phospho-PKCζ, and PKCζ in the transplanted gland. These results indicate that phenylephrine treatment moderates structural injury and improves secretory function in the transplanted submandibular gland through promoting α1-adrenoceptor expression and post-receptor signal transduction.
Collapse
Affiliation(s)
- B Xiang
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Zhong Guan Cun South St. 22, 100081, Beijing, PRC
| | | | | | | | | | | | | |
Collapse
|
7
|
Isola M, Lilliu MA. Melatonin localization in human salivary glands. J Oral Pathol Med 2015; 45:510-5. [PMID: 26694219 DOI: 10.1111/jop.12409] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND Circulating melatonin is believed to reach body fluids by crossing passively the cell membranes, but alternative ways for melatonin transport also are hypothesized. This investigation was carried out to furnish ultrastructural evidences for melatonin transport by salivary gland cells in order to indicate plausible routes by which circulating melatonin can reach saliva. METHODS Bioptic samples of parotid, submandibular and labial glands were processed for the electron microscopy and treated to demonstrate melatonin reactivity by the immunogold staining method. RESULTS AND CONCLUSIONS The preferential sites of melatonin reactivity were the granules and vesicles of serous cells. Our results suggested that the acinar cells are able to store melatonin and that the hormone can be released into saliva through granule and vesicle exocytosis. The quantitative evaluation of labelling showed that the parotid gland is the most involved in the release of melatonin in saliva.
Collapse
Affiliation(s)
- Michela Isola
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | | |
Collapse
|
8
|
Park S, Ahuja M, Kim MS, Brailoiu GC, Jha A, Zeng M, Baydyuk M, Wu LG, Wassif CA, Porter FD, Zerfas PM, Eckhaus MA, Brailoiu E, Shin DM, Muallem S. Fusion of lysosomes with secretory organelles leads to uncontrolled exocytosis in the lysosomal storage disease mucolipidosis type IV. EMBO Rep 2015; 17:266-78. [PMID: 26682800 DOI: 10.15252/embr.201541542] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 11/04/2015] [Indexed: 01/29/2023] Open
Abstract
Mutations in TRPML1 cause the lysosomal storage disease mucolipidosis type IV (MLIV). The role of TRPML1 in cell function and how the mutations cause the disease are not well understood. Most studies focus on the role of TRPML1 in constitutive membrane trafficking to and from the lysosomes. However, this cannot explain impaired neuromuscular and secretory cells' functions that mediate regulated exocytosis. Here, we analyzed several forms of regulated exocytosis in a mouse model of MLIV and, opposite to expectations, we found enhanced exocytosis in secretory glands due to enlargement of secretory granules in part due to fusion with lysosomes. Preliminary exploration of synaptic vesicle size, spontaneous mEPSCs, and glutamate secretion in neurons provided further evidence for enhanced exocytosis that was rescued by re-expression of TRPML1 in neurons. These features were not observed in Niemann-Pick type C1. These findings suggest that TRPML1 may guard against pathological fusion of lysosomes with secretory organelles and suggest a new approach toward developing treatment for MLIV.
Collapse
Affiliation(s)
- Soonhong Park
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - Malini Ahuja
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Min Seuk Kim
- Department of Oral Physiology, School of Dentistry, Wonkwang University, Iksan City, Korea
| | - G Cristina Brailoiu
- Department of Pharmaceutical Sciences, Jefferson School of Pharmacy, Thomas Jefferson University, Philadelphia, PA, USA
| | - Archana Jha
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Mei Zeng
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Maryna Baydyuk
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Christopher A Wassif
- Program on Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Forbes D Porter
- Program on Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Patricia M Zerfas
- Diagnostic and Research Services Branch, Division of Veterinary Resources, Office of Research Services, National Institutes of Health, Bethesda, MD, USA
| | - Michael A Eckhaus
- Diagnostic and Research Services Branch, Division of Veterinary Resources, Office of Research Services, National Institutes of Health, Bethesda, MD, USA
| | - Eugen Brailoiu
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA, USA
| | - Dong Min Shin
- Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| |
Collapse
|
9
|
Messenger SW, Thomas DD, Cooley MM, Jones EK, Falkowski MA, August BK, Fernandez LA, Gorelick FS, Groblewski GE. Early to Late Endosome Trafficking Controls Secretion and Zymogen Activation in Rodent and Human Pancreatic Acinar Cells. Cell Mol Gastroenterol Hepatol 2015; 1:695-709. [PMID: 26618189 PMCID: PMC4657148 DOI: 10.1016/j.jcmgh.2015.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND & AIMS Pancreatic acinar cells have an expanded apical endosomal system, the physiological and pathophysiological significance of which is still emerging. Phosphatidylinositol-3,5-bisphosphate (PI(3,5)P2) is an essential phospholipid generated by PIKfyve, which phosphorylates phosphatidylinositol-3-phosphate (PI(3)P). PI(3,5)P2 is necessary for maturation of early endosomes (EE) to late endosomes (LE). Inhibition of EE to LE trafficking enhances anterograde endosomal trafficking and secretion at the plasma membrane by default through a recycling endosome (RE) intermediate. We assessed the effects of modulating PIKfyve activity on apical trafficking and pancreatitis responses in pancreatic acinar cells. METHODS Inhibition of EE to LE trafficking was achieved using pharmacological inhibitors of PIKfyve, expression of dominant negative PIKfyve K1877E, or constitutively active Rab5-GTP Q79L. Anterograde endosomal trafficking was manipulated by expression of constitutively active and dominant negative Rab11a mutants. The effects of these agents on secretion, endolysosomal exocytosis of lysosome associated membrane protein (LAMP1), and trypsinogen activation in response to high-dose CCK-8, bile acids and cigarette toxin was determined. RESULTS PIKfyve inhibition increased basal and stimulated secretion. Adenoviral overexpression of PIKfyve decreased secretion leading to cellular death. Expression of Rab5-GTP Q79L or Rab11a-GTP Q70L enhanced secretion. Conversely, dominant-negative Rab11a-GDP S25N reduced secretion. High-dose CCK inhibited endolysosomal exocytosis that was reversed by PIKfyve inhibition. PIKfyve inhibition blocked intracellular trypsin accumulation and cellular damage responses to high CCK-8, tobacco toxin, and bile salts in both rodent and human acini. CONCLUSIONS These data demonstrate that EE-LE trafficking acutely controls acinar secretion and the intracellular activation of zymogens leading to the pathogenicity of acute pancreatitis.
Collapse
Affiliation(s)
- Scott W. Messenger
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin
| | - Diana D.H. Thomas
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin
| | - Michelle M. Cooley
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin
| | - Elaina K. Jones
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin
| | | | - Benjamin K. August
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin
| | | | - Fred S. Gorelick
- Department of Internal Medicine, School of Medicine, Yale University, New Haven, Connecticut,Department of Cell Biology, School of Medicine, Yale University, New Haven, Connecticut,Veterans Administration Connecticut Healthcare, West Haven, Connecticut
| | - Guy E. Groblewski
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin,Correspondence Address correspondence to: Guy E. Groblewski, PhD, University of Wisconsin–Madison, Department of Nutritional Sciences, 1415 Linden Drive, Madison, Wisconsin 53706. fax: (608) 262-5860.University of Wisconsin–MadisonDepartment of Nutritional Sciences1415 Linden DriveMadisonWisconsin 53706
| |
Collapse
|
10
|
Rab27A Is Present in Mouse Pancreatic Acinar Cells and Is Required for Digestive Enzyme Secretion. PLoS One 2015; 10:e0125596. [PMID: 25951179 PMCID: PMC4423933 DOI: 10.1371/journal.pone.0125596] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 03/16/2015] [Indexed: 01/24/2023] Open
Abstract
The small G-protein Rab27A has been shown to regulate the intracellular trafficking of secretory granules in various cell types. However, the presence, subcellular localization and functional impact of Rab27A on digestive enzyme secretion by mouse pancreatic acinar cells are poorly understood. Ashen mice, which lack the expression of Rab27A due to a spontaneous mutation, were used to investigate the function of Rab27A in pancreatic acinar cells. Isolated pancreatic acini were prepared from wild-type or ashen mouse pancreas by collagenase digestion, and CCK- or carbachol-induced amylase secretion was measured. Secretion occurring through the major-regulated secretory pathway, which is characterized by zymogen granules secretion, was visualized by Dextran-Texas Red labeling of exocytotic granules. The minor-regulated secretory pathway, which operates through the endosomal/lysosomal pathway, was characterized by luminal cell surface labeling of lysosomal associated membrane protein 1 (LAMP1). Compared to wild-type, expression of Rab27B was slightly increased in ashen mouse acini, while Rab3D and digestive enzymes (amylase, lipase, chymotrypsin and elastase) were not affected. Localization of Rab27B, Rab3D and amylase by immunofluorescence was similar in both wild-type and ashen acinar cells. The GTP-bound states of Rab27B and Rab3D in wild-type and ashen mouse acini also remained similar in amount. In contrast, acini from ashen mice showed decreased amylase release induced by CCK- or carbachol. Rab27A deficiency reduced the apical cell surface labeling of LAMP1, but did not affect that of Dextran-Texas Red incorporation into the fusion pockets at luminal surface. These results show that Rab27A is present in mouse pancreatic acinar cells and mainly regulates secretion through the minor-regulated pathway.
Collapse
|
11
|
Imai A, Tsujimura M, Yoshie S, Fukuda M. The small GTPase Rab33A participates in regulation of amylase release from parotid acinar cells. Biochem Biophys Res Commun 2015; 461:469-74. [PMID: 25871792 DOI: 10.1016/j.bbrc.2015.04.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 04/03/2015] [Indexed: 01/20/2023]
Abstract
Amylase is released from exocrine parotid acinar cells via typical exocytosis. Exocytosis of amylase-containing granules occurs through several steps, including formation, maturation, and transport of granules. These steps are thought to be regulated by members of the small GTPase Rab family. We previously demonstrated that Rab27 and its effectors mediate amylase release from parotid acinar cells, but the functional involvement of other Rab proteins in exocrine granule exocytosis remains largely unknown. Here, we studied isoproterenol (IPR)-induced amylase release from parotid acinar cells to investigate the possible involvement of Rab33A, which was recently suggested to regulate exocytosis in hippocampal neurons and PC12 cells. Rab33A was endogenously expressed in parotid acinar cells and present in secretory granules and the Golgi body. Functional ablation of Rab33A with anti-Rab33A antibody or a dominant-negative Rab33A-T50N mutant significantly reduced IPR-induced amylase release. Our results indicated that Rab33A is a novel component of IPR-stimulated amylase secretion from parotid acinar cells.
Collapse
Affiliation(s)
- Akane Imai
- Department of Dental Hygiene, College at Niigata, The Nippon Dental University, 1-8 Hamaura-cho, Chuo-ku, Niigata 951-8580, Japan; Department of Biochemistry, School of Life Dentistry at Niigata, The Nippon Dental University, 1-8 Hamaura-cho, Chuo-ku, Niigata 951-8580, Japan.
| | - Maiko Tsujimura
- Department of Histology, School of Life Dentistry at Niigata, The Nippon Dental University, 1-8 Hamaura-cho, Chuo-ku, Niigata 951-8580, Japan; Advanced Research Center, School of Life Dentistry at Niigata, The Nippon Dental University, 1-8 Hamaura-cho, Chuo-ku, Niigata 951-8580, Japan
| | - Sumio Yoshie
- Department of Histology, School of Life Dentistry at Niigata, The Nippon Dental University, 1-8 Hamaura-cho, Chuo-ku, Niigata 951-8580, Japan
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| |
Collapse
|
12
|
Messenger SW, Falkowski MA, Thomas DDH, Jones EK, Hong W, Gaisano HY, Giasano HY, Boulis NM, Groblewski GE. Vesicle associated membrane protein 8 (VAMP8)-mediated zymogen granule exocytosis is dependent on endosomal trafficking via the constitutive-like secretory pathway. J Biol Chem 2014; 289:28040-53. [PMID: 25138214 DOI: 10.1074/jbc.m114.593913] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Acinar cell zymogen granules (ZG) express 2 isoforms of the vesicle-associated membrane protein family (VAMP2 and -8) thought to regulate exocytosis. Expression of tetanus toxin to cleave VAMP2 in VAMP8 knock-out (-/-) acini confirmed that VAMP2 and -8 are the primary VAMPs for regulated exocytosis, each contributing ∼50% of the response. Analysis of VAMP8(-/-) acini indicated that although stimulated secretion was significantly reduced, a compensatory increase in constitutive secretion maintained total secretion equivalent to wild type (WT). Using a perifusion system to follow secretion over time revealed VAMP2 mediates an early rapid phase peaking and falling within 2-3 min, whereas VAMP8 controls a second prolonged phase that peaks at 4 min and slowly declines over 20 min to support the protracted secretory response. VAMP8(-/-) acini show increased expression of the endosomal proteins Ti-VAMP7 (2-fold) and Rab11a (4-fold) and their redistribution from endosomes to ZGs. Expression of GDP-trapped Rab11a-S25N inhibited secretion exclusively from the VAMP8 but not the VAMP2 pathway. VAMP8(-/-) acini also showed a >90% decrease in the early endosomal proteins Rab5/D52/EEA1, which control anterograde trafficking in the constitutive-like secretory pathway. In WT acini, short term (14-16 h) culture also results in a >90% decrease in Rab5/D52/EEA1 and a complete loss of the VAMP8 pathway, whereas VAMP2-secretion remains intact. Remarkably, rescue of Rab5/D52/EEA1 expression restored the VAMP8 pathway. Expressed D52 shows extensive colocalization with Rab11a and VAMP8 and partially copurifies with ZG fractions. These results indicate that robust trafficking within the constitutive-like secretory pathway is required for VAMP8- but not VAMP2-mediated ZG exocytosis.
Collapse
Affiliation(s)
- Scott W Messenger
- From the Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin 53706
| | - Michelle A Falkowski
- From the Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin 53706
| | - Diana D H Thomas
- From the Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin 53706
| | - Elaina K Jones
- From the Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin 53706
| | - Wanjin Hong
- Institute of Molecular and Cellular Biology, National University of Singapore, Singapore 138673
| | | | - Herbert Y Giasano
- Departments of Medicine and Physiology, University of Toronto, Ontario M5S 1A8, Canada, and
| | - Nicholas M Boulis
- Department of Neurosurgery, Georgia Institute of Technology, Atlanta, Georgia 30322
| | - Guy E Groblewski
- From the Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin 53706,
| |
Collapse
|
13
|
Bonnemaison M, Bäck N, Lin Y, Bonifacino JS, Mains R, Eipper B. AP-1A controls secretory granule biogenesis and trafficking of membrane secretory granule proteins. Traffic 2014; 15:1099-121. [PMID: 25040637 DOI: 10.1111/tra.12194] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 07/07/2014] [Accepted: 07/07/2014] [Indexed: 02/06/2023]
Abstract
The adaptor protein 1A complex (AP-1A) transports cargo between the trans-Golgi network (TGN) and endosomes. In professional secretory cells, AP-1A also retrieves material from immature secretory granules (SGs). The role of AP-1A in SG biogenesis was explored using AtT-20 corticotrope tumor cells expressing reduced levels of the AP-1A μ1A subunit. A twofold reduction in μ1A resulted in a decrease in TGN cisternae and immature SGs and the appearance of regulated secretory pathway components in non-condensing SGs. Although basal secretion of endogenous SG proteins was unaffected, secretagogue-stimulated release was halved. The reduced μ1A levels interfered with the normal trafficking of carboxypeptidase D (CPD) and peptidylglycine α-amidating monooxygenase-1 (PAM-1), integral membrane enzymes that enter immature SGs. The non-condensing SGs contained POMC products and PAM-1, but not CPD. Based on metabolic labeling and secretion experiments, the cleavage of newly synthesized PAM-1 into PHM was unaltered, but PHM basal secretion was increased in sh-μ1A PAM-1 cells. Despite lacking a canonical AP-1A binding motif, yeast two-hybrid studies demonstrated an interaction between the PAM-1 cytosolic domain and AP-1A. Coimmunoprecipitation experiments with PAM-1 mutants revealed an influence of the luminal domains of PAM-1 on this interaction. Thus, AP-1A is crucial for normal SG biogenesis, function and composition.
Collapse
Affiliation(s)
- Mathilde Bonnemaison
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, 06030, USA
| | | | | | | | | | | |
Collapse
|
14
|
Racz GZ, Zheng C, Goldsmith CM, Baum BJ, Cawley NX. Toward gene therapy for growth hormone deficiency via salivary gland expression of growth hormone. Oral Dis 2014; 21:149-55. [PMID: 24320050 DOI: 10.1111/odi.12217] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 11/11/2013] [Accepted: 11/18/2013] [Indexed: 12/14/2022]
Abstract
OBJECTIVES Salivary glands are useful targets for gene therapeutics. After gene transfer into salivary glands, regulated secretory pathway proteins, such as human growth hormone, are secreted into saliva, whereas constitutive secretory pathway proteins, such as erythropoietin, are secreted into the bloodstream. Secretion of human growth hormone (hGH) into the saliva is not therapeutically useful. In this study, we attempted to redirect the secretion of transgenic hGH from the saliva to the serum by site-directed mutagenesis. MATERIALS AND METHODS We tested hGH mutants first in vitro with AtT20 cells, a model endocrine cell line that exhibits polarized secretion of regulated secretory pathway proteins. Selected mutants were further studied in vivo using adenoviral-mediated gene transfer to rat submandibular glands. RESULTS We identified two mutants with differences in secretion behavior compared to wild-type hGH. One mutant, ΔN1-6 , was detected in the serum of transduced rats, demonstrating that expression of this mutant in the salivary gland resulted in its secretion through the constitutive secretory pathway. CONCLUSION This study demonstrates that mutagenesis of therapeutic proteins normally destined for the regulated secretory pathway may result in their secretion via the constitutive secretory pathway into the circulation for potential therapeutic benefit.
Collapse
Affiliation(s)
- G Z Racz
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | | | | | | | | |
Collapse
|
15
|
Fujita-Yoshigaki J, Matsuki-Fukushima M, Yokoyama M, Katsumata-Kato O. Sorting of a HaloTag protein that has only a signal peptide sequence into exocrine secretory granules without protein aggregation. Am J Physiol Gastrointest Liver Physiol 2013; 305:G685-96. [PMID: 24029466 DOI: 10.1152/ajpgi.00093.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The mechanism involved in the sorting and accumulation of secretory cargo proteins, such as amylase, into secretory granules of exocrine cells remains to be solved. To clarify that sorting mechanism, we expressed a reporter protein HaloTag fused with partial sequences of salivary amylase protein in primary cultured parotid acinar cells. We found that a HaloTag protein fused with only the signal peptide sequence (Met(1)-Ala(25)) of amylase, termed SS25H, colocalized well with endogenous amylase, which was confirmed by immunofluorescence microscopy. Percoll-density gradient centrifugation of secretory granule fractions shows that the distributions of amylase and SS25H were similar. These results suggest that SS25H is transported to secretory granules and is not discriminated from endogenous amylase by the machinery that functions to remove proteins other than granule cargo from immature granules. Another reporter protein, DsRed2, that has the same signal peptide sequence also colocalized with amylase, suggesting that the sorting to secretory granules is not dependent on a characteristic of the HaloTag protein. Whereas Blue Native PAGE demonstrates that endogenous amylase forms a high-molecular-weight complex, SS25H does not participate in the complex and does not form self-aggregates. Nevertheless, SS25H was released from cells by the addition of a β-adrenergic agonist, isoproterenol, which also induces amylase secretion. These results indicate that addition of the signal peptide sequence, which is necessary for the translocation in the endoplasmic reticulum, is sufficient for the transportation and storage of cargo proteins in secretory granules of exocrine cells.
Collapse
Affiliation(s)
- Junko Fujita-Yoshigaki
- Dept. of Physiology, Nihon Univ., School of Dentistry at Matsudo, 2-870-1 Sakaecho-nishi, Matsudo, Chiba, 271-8587, Japan.
| | | | | | | |
Collapse
|
16
|
Messenger SW, Thomas DDH, Falkowski MA, Byrne JA, Gorelick FS, Groblewski GE. Tumor protein D52 controls trafficking of an apical endolysosomal secretory pathway in pancreatic acinar cells. Am J Physiol Gastrointest Liver Physiol 2013; 305:G439-52. [PMID: 23868405 PMCID: PMC3761242 DOI: 10.1152/ajpgi.00143.2013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 07/12/2013] [Indexed: 01/31/2023]
Abstract
Zymogen granule (ZG) formation in acinar cells involves zymogen cargo sorting from trans-Golgi into immature secretory granules (ISGs). ISG maturation progresses by removal of lysosomal membrane and select content proteins, which enter endosomal intermediates prior to their apical exocytosis. Constitutive and stimulated secretion through this mechanism is termed the constitutive-like and minor-regulated pathways, respectively. However, the molecular components that control membrane trafficking within these endosomal compartments are largely unknown. We show that tumor protein D52 is highly expressed in endosomal compartments following pancreatic acinar cell stimulation and regulates apical exocytosis of an apically directed endolysosomal compartment. Secretion from the endolysosomal compartment was detected by cell-surface antigen labeling of lysosome-associated membrane protein LAMP1, which is absent from ZGs, and had incomplete overlap with surface labeling of synaptotagmin 1, a marker of ZG exocytosis. Although culturing (16-18 h) of isolated acinar cells is accompanied by a loss of secretory responsiveness, the levels of SNARE proteins necessary for ZG exocytosis were preserved. However, levels of endolysosomal proteins D52, EEA1, Rab5, and LAMP1 markedly decreased with culture. When D52 levels were restored by adenoviral delivery, the levels of these regulatory proteins and secretion of both LAMP1 (endolysosomal) and amylase was strongly enhanced. These secretory effects were absent in alanine and aspartate substitutions of serine 136, the major D52 phosphorylation site, and were inhibited by brefeldin A, which does not directly affect the ZG compartment. Our results indicate that D52 directly regulates apical endolysosomal secretion and are consistent with previous studies, suggesting that this pathway indirectly regulates ZG secretion of digestive enzymes.
Collapse
Affiliation(s)
- Scott W Messenger
- Univ. of Wisconsin, Dept. of Nutritional Sciences, 1415 Linden Dr., Madison, WI 53706.
| | | | | | | | | | | |
Collapse
|
17
|
Isola M, Ekström J, Diana M, Solinas P, Cossu M, Lilliu MA, Loy F, Isola R. Subcellular distribution of melatonin receptors in human parotid glands. J Anat 2013; 223:519-24. [PMID: 23998562 DOI: 10.1111/joa.12105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2013] [Indexed: 12/29/2022] Open
Abstract
The hormone melatonin influences oral health through a variety of actions, such as anti-inflammatory, anti-oxidant, immunomodulatory and antitumour. Many of these melatonin functions are mediated by a family of membrane receptors expressed in the oral epithelium and salivary glands. Using immunoblotting and immunohistochemistry, recent studies have shown that the melatonin membrane receptors, MT1 and MT2, are present in rat and human salivary glands. To date, no investigation has dealt with the ultrastructural distribution of the melatonin receptors. This was the aim of the present study, using the immunogold method applied to the human parotid gland. Reactivity to MT1 and, with less intensity, to MT2 appeared in the secretory granules of acinar cells and in the cytoplasmic vesicles of both acinar and ductal cells. Plasma membranes were also stained, albeit slightly. The peculiar intracytoplasmic distribution of these receptors may indicate that there is an uptake/transport system for melatonin from the circulation into the saliva.
Collapse
Affiliation(s)
- M Isola
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Loy F, Diana M, Isola R, Solinas P, Isola M, Conti G, Lantini MS, Cossu M, Riva A, Ekström J. Morphological evidence that pentagastrin regulates secretion in the human parotid gland. J Anat 2012; 220:447-53. [PMID: 22414238 DOI: 10.1111/j.1469-7580.2012.01489.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Salivary secretion is principally regulated by autonomic nerves. However, recent evidence from in vivo animal experiments suggests that gastrointestinal peptide hormones can also influence saliva production. The aim of the present study was to define the secretagogue activity of the gastrin-analogue pentagastrin in human salivary glands. For this purpose, parotid tissues were exposed to pentagastrin in vitro. Morphological techniques were used to evaluate modifications to serous acinar cells associated with secretion. Using a variant of the osmium maceration method, high resolution scanning electron microscopy allowed assessment of the morphology of the cytoplasmic aspect of the plasmalemma to demonstrate secretory activity. To quantify responses to pentagastrin, we recorded morphometric data on microvilli, microbuds, and protrusions. Dose-dependent morphological changes were observed, whereas protein concentration increased in the incubate. The use of selective receptor antagonists showed pentagastrin to act principally via cholecystokinin-A receptors. The morphological responses observed following exposure to pentagastrin differed from those elicited following exposure to the pan-muscarinic agonist carbachol. This study provides the first demonstration of a direct secretory action of gastrointestinal peptides on salivary glands in humans.
Collapse
Affiliation(s)
- Francesco Loy
- Department of Cytomorphology, University of Cagliari, Cagliari, Italy.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Miozza V, Sánchez G, Sterin-Borda L, Busch L. Enhancement of carbachol-induced amylase secretion in parotid glands from rats with experimental periodontitis. Arch Oral Biol 2011; 56:1514-20. [PMID: 21741619 DOI: 10.1016/j.archoralbio.2011.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 05/23/2011] [Accepted: 06/16/2011] [Indexed: 11/26/2022]
Abstract
OBJECTIVE In a previous study we observed that parotid glands from rats with experimental periodontitis showed an increase in basal amylase release as a result of an increase in cAMP accumulation induced by PGE(2) production. The aim of this work was to study whether this change in amylase release influences the secretory effect of carbachol. DESIGN Experimental periodontitis was induced through placing a black thread around the cervix of the two lower first molars. Experiments were done 22 days after ligature induced periodontitis. Amylase release was evaluated in vitro and determined using a colorimetric method which uses starch as substrate. RESULTS The effect of carbachol was increased in parotid glands from periodontitis rats. The effect of 10(-6)M carbachol was inhibited by 4-DAMP (10(-6)M), U-73122 (5 × 10(-6)M) and trifluoperazine (5 × 10(-6)M) in both groups. No changes were observed in the binding sites and affinity in parotid membranes from rats with experimental periodontitis. The inhibition of the adenylyl cyclase and the cyclooxygenase induced a right shift of the carbachol concentration-response curve in periodontitis group whilst the opposite effect was observed in control group in the presence of db-cAMP and PGE(2). CONCLUSIONS Parotid glands from rats with experimental periodontitis release more amylase in response to carbachol suggesting an interaction between Ca(2+) and cAMP in the fusion/exocytosis step of secretory vesicles.
Collapse
Affiliation(s)
- Valeria Miozza
- Pharmacology Unit, School of Dentistry, University of Buenos Aires, Marcelo T. de Alvear 2142 (1122AAH), Buenos Aires, Argentina
| | | | | | | |
Collapse
|
20
|
Miozza V, Borda E, Sterin-Borda L, Busch L. Experimental periodontitis induces a cAMP-dependent increase in amylase activity in parotid glands from male rats. Inflammation 2010; 32:357-63. [PMID: 19669869 DOI: 10.1007/s10753-009-9142-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
It is known that subjects with periodontitis show enhanced amylase concentration in saliva. Our purpose was to analyze the release of amylase in parotid glands from rats with experimental periodontitis and controls. We present evidence that periodontitis induces an increase in resting amylase activity and release without changes in isoproterenol-induced amylase secretion. Changes in amylase were reverted by the inhibition of the adenylyl cyclase by SQ 22536, the cyclooxygenase type 1 by FR 122047 and by blocking the vasoactive intestinal peptide (VIP) receptor with VIP 6-28. Parotid glands from rats with periodontitis showed an increase in cAMP levels that was also reverted in the presence of SQ 22536, FR 122047 and VIP 6-28. We concluded that both PGE(2) and VIP are produced in parotid glands from rats with periodontitis and, by activating their own receptors in acinar cells, induce cAMP accumulation leading to an increase in amylase basal secretion.
Collapse
Affiliation(s)
- Valeria Miozza
- Cátedra de Farmacología, Facultad de Odontología, Universidad de Buenos Aires, Marcelo T de Alvear 2142 (1122AAH), Buenos Aires, Argentina
| | | | | | | |
Collapse
|
21
|
Racz GZ, Perez-Riveros P, Adriaansen J, Zheng C, Baum BJ. In vivo secretion of the mouse immunoglobulin G Fc fragment from rat submandibular glands. J Gene Med 2009; 11:580-7. [PMID: 19424985 DOI: 10.1002/jgm.1340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Salivary glands have been proposed as target organs for gene therapy. They secrete endogenous, as well as transgenic proteins, in a polarized manner. Transgene-encoded regulated pathway proteins primarily follow the regulated pathway in rat salivary glands and are secreted into saliva in an exocrine manner. Conversely, constitutive pathway proteins generally are secreted more basolaterally and thus follow the endocrine route. In the present study, we studied in vivo the sorting of the mouse immunoglobulin G2b Fc fragment, which is physiologically secreted via the constitutive pathway. METHODS Adenoviral vectors encoding the Fc fragment and human growth hormone were delivered into rat and mouse submandibular glands in vivo to compare their serum-to-saliva distribution. We also compared the intracellular localization of the Fc fragment and growth hormone by confocal microscopy. RESULTS We found that the Fc fragment was secreted almost entirely into the bloodstream from rat and mouse submandibular glands via a constitutive or constitutive-like pathway. This sorting behaviour is clearly different from that of transgenic human growth hormone, which is secreted in a regulated pathway, both in neuroendocrine cells and as a transgenic protein from salivary gland cells. We also found that simultaneously expressed human growth hormone and the mouse Fc fragment do not appear to influence each other's sorting behaviour. The Fc fragment showed a primarily basal localization, whereas growth hormone showed an apical localization, in rat submandibular gland acinar cells. CONCLUSIONS The results obtained in the present study indicate that the mouse Fc fragment is a useful model protein for examining the basolateral versus apical secretory pathways employed by transgenic secretory proteins in salivary glands.
Collapse
Affiliation(s)
- Gabor Z Racz
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA.
| | | | | | | | | |
Collapse
|
22
|
Adriaansen J, Perez P, Goldsmith CM, Zheng C, Baum BJ. Differential sorting of human parathyroid hormone after transduction of mouse and rat salivary glands. Hum Gene Ther 2009; 19:1021-8. [PMID: 18694295 DOI: 10.1089/hum.2008.079] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Gene transfer to salivary glands leads to abundant secretion of transgenic protein into either saliva or the bloodstream. This indicates significant clinical potential, depending on the route of sorting. The aim of this study was to probe the sorting characteristics of human parathyroid hormone (hPTH) in two animal models for salivary gland gene transfer. PTH is a key hormone regulating calcium levels in the blood. A recombinant serotype 5 adenoviral vector carrying the hPTH cDNA was administered to the submandibular glands of mice and rats. Two days after delivery, high levels of hPTH were found in the serum of mice, leading to elevated serum calcium levels. Only low amounts of hPTH were found in the saliva. Two days after vector infusion into rats, a massive secretion of hPTH was measured in saliva, with little secretion into serum. Confocal microscopy showed hPTH in the glands, localized basolaterally in mice and apically in rats. Submandibular gland transduction was effective and the produced hPTH was biologically active in vivo. Whereas hPTH sorted toward the basolateral side in mice, in rats hPTH was secreted mainly at the apical side. These results indicate that the interaction between hPTH and the cell sorting machinery is different between mouse and rat salivary glands. Detailed studies in these two species should result in a better understanding of cellular control of transgenic secretory protein sorting in this tissue.
Collapse
Affiliation(s)
- J Adriaansen
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-1190, USA.
| | | | | | | | | |
Collapse
|
23
|
Saegusa C, Kanno E, Itohara S, Fukuda M. Expression of Rab27B-binding protein Slp1 in pancreatic acinar cells and its involvement in amylase secretion. Arch Biochem Biophys 2008; 475:87-92. [PMID: 18477466 DOI: 10.1016/j.abb.2008.04.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Accepted: 04/18/2008] [Indexed: 12/16/2022]
Abstract
Slp1 is a putative Rab27 effector protein and implicated in intracellular membrane transport; however, the precise tissue distribution and function of Slp1 protein remain largely unknown. In this study we investigated the tissue distribution of Slp1 in mice and found that Slp1 is abundantly expressed in the pancreas, especially in the apical region of pancreatic acinar cells. Slp1 interacted with Rab27B in vivo and both proteins were co-localized on zymogen granules. Morphological analysis of fasted Slp1 knockout mice showed an increased number of zymogen granules in the pancreatic acinar cells, indicating that Slp1 is part of the machinery of amylase secretion by the exocrine pancreas.
Collapse
Affiliation(s)
- Chika Saegusa
- Fukuda Initiative Research Unit, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | | | | | | |
Collapse
|
24
|
Origins of the regulated secretory pathway. THE GOLGI APPARATUS 2008. [PMCID: PMC7121582 DOI: 10.1007/978-3-211-76310-0_30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Modes of transport of soluble (or luminal) secretory proteins synthesized in the endoplasmic reticulum (ER) could be divided into two groups. The socalled constitutive secretory pathway (CSP) is common to all eukaryotic cells, constantly delivering constitutive soluble secretory proteins (CSSPs) linked to the rate of protein synthesis but largely independent of external stimuli. In regulated secretion, protein is sorted from the Golgi into storage/secretory granules (SGs) whose contents are released when stimuli trigger their final fusion with the plasma membrane (Hannah et al. 1999).
Collapse
|
25
|
Aframian DJ, Amit D, David R, Shai E, Deutsch D, Honigman A, Panet A, Palmon A. Reengineering salivary gland cells to enhance protein secretion for use in developing artificial salivary gland device. ACTA ACUST UNITED AC 2007; 13:995-1001. [PMID: 17346100 DOI: 10.1089/ten.2006.0300] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Salivary glands (SGs) are considered exocrine glands, which mainly secrete water into the oral cavity. Nevertheless, they also exhibit a smaller endocrine secretory pathway toward the bloodstream. The concept of an artificial SG device for exocrine fluid secretion into the oral region in xerostomic patients has been previously studied. The purpose of the current study was to examine the potential of such a device for enhancing bioactive protein secretion. We engineered a plasmid encoding a SG-specific signal peptide sequence adjacent to a normally nonsecreted encoded reporter gene creating a chimera protein, and examined if this construct can enhance secretion from salivary epithelial cells. An N-terminal encoding epidermal growth factor (EGF) sequence was synthesized and inserted into a pGL3 control vector 5' of a firefly luciferase gene, creating a pGL3-EGF signal peptide (pGL3-EGFSP) fused vector. This vector was cotransfected with a pRL-CMV vector containing a Renilla luciferase gene, in 293 cells (serving as controls), and human submandibular gland ductal epithelial (HSG), rat submandibular gland acinar epithelial (SMIE), and rat submandibular gland ductal epithelial (A5) salivary cell lines. The transfected 293, SMIE, and HSG cells showed 8-, 18-, and 40-fold higher luciferase activity, respectively. These observations lead to the concept of an envisioned secretory device, which can serve as a potential biological pump for bioactive proteins.
Collapse
Affiliation(s)
- Doron J Aframian
- Salivary Gland Clinic, Department of Oral Medicine, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Proctor GB, Carpenter GH. Regulation of salivary gland function by autonomic nerves. Auton Neurosci 2006; 133:3-18. [PMID: 17157080 DOI: 10.1016/j.autneu.2006.10.006] [Citation(s) in RCA: 458] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 10/06/2006] [Accepted: 10/20/2006] [Indexed: 11/24/2022]
Abstract
Oral homeostasis is dependent upon saliva and its content of proteins. Reflex salivary flow occurs at a low 'resting' rate and for short periods of the day more intense taste or chewing stimuli evoke up to ten fold increases in salivation. The secretion of salivary fluid and proteins is controlled by autonomic nerves. All salivary glands are supplied by cholinergic parasympathetic nerves which release acetylcholine that binds to M3 and (to a lesser extent) M1 muscarinic receptors, evoking the secretion of saliva by acinar cells in the endpieces of the salivary gland ductal tree. Most salivary glands also receive a variable innervation from sympathetic nerves which released noradrenaline from which tends to evoke greater release of stored proteins, mostly from acinar cells but also ductal cells. There is some 'cross-talk' between the calcium and cyclic AMP intracellular pathways coupling autonomic stimulation to secretion and salivary protein secretion is augmented during combined stimulation. Other non-adrenergic, non-cholinergic neuropeptides released from autonomic nerves evoke salivary gland secretion and parasympathetically derived vasointestinal peptide, acting through endothelial cell derived nitric oxide, plays a role in the reflex vasodilatation that accompanies secretion. Neuronal type, calcium-activated, soluble nitric oxide within salivary cells appears to play a role in mediating salivary protein secretion in response to autonomimetics. Fluid secretion by salivary glands involves aquaporin 5 and the extent to which the expression of aquaporin 5 on apical acinar cell membranes is upregulated by cholinomimetics remains uncertain. Extended periods of autonomic denervation, liquid diet feeding (reduced reflex stimulation) or duct ligation cause salivary gland atrophy. The latter two are reversible, demonstrating that glands can regenerate provided that the autonomic innervation remains intact. The mechanisms by which nerves integrate with salivary cells during regeneration or during salivary gland development remain to be elucidated.
Collapse
Affiliation(s)
- Gordon B Proctor
- Salivary Research Unit, King's College London Dental Institute, Floor 17 Guy's Tower, London SE1 9RT, UK.
| | | |
Collapse
|
27
|
Imai A, Yoshie S, Nashida T, Shimomura H, Fukuda M. Functional involvement of Noc2, a Rab27 effector, in rat parotid acinar cells. Arch Biochem Biophys 2006; 455:127-35. [PMID: 17067543 DOI: 10.1016/j.abb.2006.09.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Revised: 09/17/2006] [Accepted: 09/18/2006] [Indexed: 11/23/2022]
Abstract
Noc2 has recently been proposed to regulate exocytosis in both endocrine and exocrine cells; however, protein expression, subcellular localization and function of Noc2 in exocrine cells have never been elucidated. In this study, we investigated whether Noc2, a Rab27 effector, is involved in isoproterenol (IPR)-stimulated amylase release from acinar cells. Rab27 was detected in the apical plasma membrane (APM) and secretory granule membrane (SGM) fractions, and was translocated to the APM after IPR stimulation for 5 min, but was detected at lower levels in the APM after 30 min. In contrast, although Noc2 was expressed in SGM bound to Rab27, Noc2 was not translocated to APM and the Noc2/Rab27 complex was disrupted after stimulation with IPR for short time. In addition, the anti-Noc2-Rab-binding-domain antibody inhibited IPR-stimulated amylase release from streptolysin O-permeabilized parotid acinar cells. Our results suggest that the Noc2/Rab27 complex is an important constituent of the early stages of IPR-stimulated amylase release.
Collapse
Affiliation(s)
- Akane Imai
- Department of Biochemistry, The Nippon Dental University, School of Life Dentistry at Niigata, 1-8 Hamaura-cho, Niigata 951-8580, Japan.
| | | | | | | | | |
Collapse
|
28
|
Chen Y, Warner JD, Yule DI, Giovannucci DR. Spatiotemporal analysis of exocytosis in mouse parotid acinar cells. Am J Physiol Cell Physiol 2005; 289:C1209-19. [PMID: 16000640 DOI: 10.1152/ajpcell.00159.2005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Exocrine cells of the digestive system are specialized to secrete protein and fluid in response to neuronal and/or hormonal input. Although morphologically similar, parotid and pancreatic acinar cells exhibit important functional divergence in Ca(2+) signaling properties. To address whether there are fundamental differences in exocytotic release of digestive enzyme from exocrine cells of salivary gland versus pancreas, we applied electrophysiological and optical methods to investigate spatial and temporal characteristics of zymogen-containing secretory granule fusion at the single-acinar cell level by direct or agonist-induced Ca(2+) and cAMP elevation. Temporally resolved membrane capacitance measurements revealed that two apparent phases of exocytosis were induced by Ca(2+) elevation: a rapidly activated initial phase that could not be resolved as individual fusion events and a second phase that was activated after a delay, increased in a staircaselike fashion, was augmented by cAMP elevation, and likely reflected both sequential compound and multivesicular fusion of zymogen-containing granules. Optical measurements of exocytosis with time-differential imaging analysis revealed that zymogen granule fusion was induced after a minimum delay of approximately 200 ms, occurred initially at apical and basolateral borders of acinar cells, and under strong stimulation proceeded from apical pole to deeper regions of the cell interior. Zymogen granule fusions appeared to coordinate subsequent fusions and produced persistent structures that generally lasted several minutes. In addition, parotid gland slices were used to assess secretory dynamics in a more physiological context. Parotid acinar cells were shown to exhibit both similar and divergent properties compared with the better-studied pancreatic acinar cell regarding spatial organization and kinetics of exocytotic fusion of zymogen granules.
Collapse
Affiliation(s)
- Ying Chen
- Department of Neurosciences, Medical College of Ohio, Toledo, OH 43614, USA
| | | | | | | |
Collapse
|
29
|
Gorr SU, Venkatesh S, Darling D. Parotid secretory granules: crossroads of secretory pathways and protein storage. J Dent Res 2005; 84:500-9. [PMID: 15914585 PMCID: PMC1939692 DOI: 10.1177/154405910508400604] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Saliva plays an important role in digestion, host defense, and lubrication. The parotid gland contributes a variety of secretory proteins-including amylase, proline-rich proteins, and parotid secretory protein (PSP)-to these functions. The regulated secretion of salivary proteins ensures the availability of the correct mix of salivary proteins when needed. In addition, the major salivary glands are targets for gene therapy protocols aimed at targeting therapeutic proteins either to the oral cavity or to circulation. To be successful, such protocols must be based on a solid understanding of protein trafficking in salivary gland cells. In this paper, model systems available to study the secretion of salivary proteins are reviewed. Parotid secretory proteins are stored in large dense-core secretory granules that undergo stimulated secretion in response to extracellular stimulation. Secretory proteins that are not stored in large secretory granules are secreted by either the minor regulated secretory pathway, constitutive secretory pathways (apical or basolateral), or the constitutive-like secretory pathway. It is proposed that the maturing secretory granules act as a distribution center for secretory proteins in salivary acinar cells. Protein distribution or sorting is thought to involve their selective retention during secretory granule maturation. Unlike regulated secretory proteins in other cell types, salivary proteins do not exhibit calcium-induced aggregation. Instead, sulfated proteoglycans play a role in the storage of secretory proteins in parotid acinar cells. This work suggests that unique sorting and retention mechanisms are responsible for the distribution of secretory proteins to different secretory pathways from the maturing secretory granules in parotid acinar cells.
Collapse
Affiliation(s)
- S.-U. Gorr
- Department of Periodontics, Endodontics and Dental Hygiene and Center for Oral Health and Systemic Disease, University of Louisville School of Dentistry, Louisville, KY 40292, USA
| | - S.G. Venkatesh
- Department of Periodontics, Endodontics and Dental Hygiene and Center for Oral Health and Systemic Disease, University of Louisville School of Dentistry, Louisville, KY 40292, USA
| | - D.S. Darling
- Department of Periodontics, Endodontics and Dental Hygiene and Center for Oral Health and Systemic Disease, University of Louisville School of Dentistry, Louisville, KY 40292, USA
| |
Collapse
|
30
|
Bauer RA, Overlease RL, Lieber JL, Angleson JK. Retention and stimulus-dependent recycling of dense core vesicle content in neuroendocrine cells. J Cell Sci 2004; 117:2193-202. [PMID: 15126621 DOI: 10.1242/jcs.01093] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We have used fluorescence imaging of individual exocytic events in combination with immunogold electron microscopy and FM1-43 photoconversion to study the stimulus-dependent recycling of dense core vesicle content in isolated rat pituitary lactotrophs. Secretory stimulation with high external [K+] resulted in 100 exocytic sites per cell that were labeled by extracellular antibodies against the peptide hormone prolactin. Morphological analysis demonstrated that the prolactin was retained and internalized in intact dense cores. Vesicles containing non-secreted, internalized prolactin did not colocalize with DiI-LDL that had been chased into lysosomes but did transiently colocalize with internalized transferrin. The recycling vesicles also trafficked through a syntaxin 6-positive compartment but not the TGN38-positive trans-Golgi. Recycling vesicles, which returned to the cell surface in a slow basal manner, could also be stimulated to undergo exocytosis with a high release probability during subsequent exocytic stimulation with external K+. These studies suggest a functional role for recycling vesicles that retain prolactin.
Collapse
Affiliation(s)
- Roslyn A Bauer
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | | | | | | |
Collapse
|
31
|
Venkatesh SG, Cowley DJ, Gorr SU. Differential aggregation properties of secretory proteins that are stored in exocrine secretory granules of the pancreas and parotid glands. Am J Physiol Cell Physiol 2003; 286:C365-71. [PMID: 14576088 DOI: 10.1152/ajpcell.00338.2003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Low-pH- and calcium-induced aggregation of regulated secretory proteins has been proposed to play a role in their retention and storage in secretory granules. However, this has not been tested for secretory proteins that are stored in the exocrine parotid secretory granules. Parotid granule matrix proteins were analyzed for aggregation in the presence or absence of calcium and in the pH range of 5.5 to 7.5. Amylase did not aggregate under these conditions, although <10% of parotid secretory protein (PSP) aggregated below pH 6.0. To test aggregation directly in isolated granules, rat parotid secretory granules were permeabilized with 0.1% saponin in the presence or absence of calcium and in the pH range of 5.0 to 8.4. In contrast to the low-pH-dependent retention of amylase in exocrine pancreatic granules, amylase was quantitatively released and most PSP was released from parotid granules under all conditions. Both proteins were completely released upon granule membrane solubilization. Thus neither amylase nor PSP show low-pH- or calcium-induced aggregation under physiological conditions in the exocrine parotid secretory granules.
Collapse
Affiliation(s)
- S G Venkatesh
- Department of Periodontics, Endodontics, and Dental Hygiene, University of Louisville Health Sciences Center, Louisville, KY 40292, USA
| | | | | |
Collapse
|
32
|
Feng L, Arvan P. The trafficking of alpha 1-antitrypsin, a post-Golgi secretory pathway marker, in INS-1 pancreatic beta cells. J Biol Chem 2003; 278:31486-94. [PMID: 12796484 DOI: 10.1074/jbc.m305690200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A sulfated alpha1-antitrypsin (AAT), thought to be a default secretory pathway marker, is not stored in secretory granules when expressed in neuroendocrine PC12 cells. In search of a constitutive secretory pathway marker for pancreatic beta cells, we produced INS-1 cells stably expressing wild-type AAT. Because newly synthesized AAT arrives very rapidly in the Golgi complex, kinetics alone cannot resolve AAT release via distinct secretory pathways, although most AAT is secreted within a few hours and virtually none is stored in mature granules. Nevertheless, from pulse-chase analyses, a major fraction of newly synthesized AAT transiently exhibits secretogogue-stimulated exocytosis and localizes within immature secretory granules (ISGs). This trafficking occurs without detectable AAT polymerization or binding to lipid rafts. Remarkably, in a manner not requiring its glycans, all of the newly synthesized AAT is then removed from granules during their maturation, leading mostly to constitutive-like AAT secretion, whereas a smaller fraction (approximately 10%) goes on to lysosomes. Secretogogue-stimulated ISG exocytosis reroutes newly synthesized AAT directly into the medium and prevents its arrival in lysosomes. These data are most consistent with the idea that soluble AAT abundantly enters ISGs and then is efficiently relocated to the endosomal system, from which many molecules undergo constitutive-like secretion while a smaller fraction advances to lysosomes.
Collapse
Affiliation(s)
- Lijun Feng
- Division of Endocrinology and Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | |
Collapse
|
33
|
Abstract
Regulated exocytosis of secretory granules or dense-core granules has been examined in many well-characterized cell types including neurons, neuroendocrine, endocrine, exocrine, and hemopoietic cells and also in other less well-studied cell types. Secretory granule exocytosis occurs through mechanisms with many aspects in common with synaptic vesicle exocytosis and most likely uses the same basic protein components. Despite the widespread expression and conservation of a core exocytotic machinery, many variations occur in the control of secretory granule exocytosis that are related to the specialized physiological role of particular cell types. In this review we describe the wide range of cell types in which regulated secretory granule exocytosis occurs and assess the evidence for the expression of the conserved fusion machinery in these cells. The signals that trigger and regulate exocytosis are reviewed. Aspects of the control of exocytosis that are specific for secretory granules compared with synaptic vesicles or for particular cell types are described and compared to define the range of accessory control mechanisms that exert their effects on the core exocytotic machinery.
Collapse
Affiliation(s)
- Robert D Burgoyne
- The Physiological Laboratory, University of Liverpool, United Kingdom.
| | | |
Collapse
|
34
|
Castle AM, Huang AY, Castle JD. The minor regulated pathway, a rapid component of salivary secretion, may provide docking/fusion sites for granule exocytosis at the apical surface of acinar cells. J Cell Sci 2002; 115:2963-73. [PMID: 12082156 DOI: 10.1242/jcs.115.14.2963] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recently, we reported that the minor regulated and constitutive-like pathways are the main source of resting secretion by parotid acinar cells. Using tissue lobules biosynthetically labeled with [35S]amino acids, we now show that discharge of the minor regulated pathway precedes granule exocytosis stimulated by isoproterenol (≥1 μM) or carbachol (2μM). Stimulation of the minor regulated pathway by 40 nM carbachol as well as altering its trafficking, either by adding brefeldin A or by incubating in K+-free medium, cause potentiation of amylase secretion stimulated by isoproterenol, suggesting that the minor regulated pathway contributes to the mechanism of potentiation. Both exocytosis of the minor regulated pathway and the potentiation-inducing treatments induce relocation of immunostained subapical puncta of the SNARE protein syntaxin 3 into the apical plasma membrane. Rab11 and possibly VAMP2 may be concentrated in the same relocating foci. These results suggest that the minor regulated pathway and granule exocytosis are functionally linked and that the minor regulated pathway has a second role beyond contributing to resting secretion — providing surface docking/fusion sites for granule exocytosis. In the current model of salivary protein export, discharge of the minor regulated pathway by eitherβ-adrenergic or cholinergic stimulation is an obligatory first step. Ensuing granule exocytosis is controlled mainly by β-adrenergic stimulation whereas cholinergic stimulation mainly regulates the number of surface sites where release occurs.
Collapse
Affiliation(s)
- Anna M Castle
- Department of Cell Biology, University of Virginia Health System, School of Medicine, Charlottesville 22908-0732, USA
| | | | | |
Collapse
|
35
|
Huang AY, Castle AM, Hinton BT, Castle JD. Resting (basal) secretion of proteins is provided by the minor regulated and constitutive-like pathways and not granule exocytosis in parotid acinar cells. J Biol Chem 2001; 276:22296-306. [PMID: 11301325 DOI: 10.1074/jbc.m100211200] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Resting secretion of salivary proteins by the parotid gland is sustained in situ between periods of eating by parasympathetic stimulation and has been assumed to involve low level granule exocytosis. By using parotid lobules from ad libitum fed rats stimulated with low doses of carbachol as an in vitro analog of resting secretion, we deduce from the composition of discharged proteins that secretion does not involve granule exocytosis. Rather, it derives from two other acinar export routes, the constitutive-like (stimulus-independent) pathway and the minor regulated pathway, which responds to low doses of cholinergic or beta-adrenergic agonists (Castle, J. D., and Castle, A. M. (1996) J. Cell Sci. 109, 2591-2599). The protein composition collected in vitro mimics that collected from cannulated ducts of glands given low level stimulation in situ. Analysis of secretory trafficking along the two pathways of resting secretion has indicated that the constitutive-like pathway may pass through endosomes after diverging from the minor regulated pathway at a brefeldin A-sensitive branch point. The branch point is deduced to be distal to a common vesicular budding event by which both pathways originate from immature granules. Detectable perturbation of neither pathway in lobules was observed by wortmannin addition, and neither serves as a significant export route for lysosomal procathepsin B. These findings show that parotid acinar cells use low capacity, high sensitivity secretory pathways for resting secretion and reserve granule exocytosis, a high capacity, low sensitivity pathway, for massive salivary protein export during meals. An analogous strategy may be employed in other secretory cell types.
Collapse
Affiliation(s)
- A Y Huang
- Department of Cell Biology, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908, USA
| | | | | | | |
Collapse
|
36
|
Baum BJ, Berkman ME, Marmary Y, Goldsmith CM, Baccaglini L, Wang S, Wellner RB, Hoque AT, Atkinson JC, Yamagishi H, Kagami H, Parlow AF, Chao J. Polarized secretion of transgene products from salivary glands in vivo. Hum Gene Ther 1999; 10:2789-97. [PMID: 10584925 DOI: 10.1089/10430349950016528] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Previously (Kagami et al. Hum. Gene Ther. 1996;7:2177-2184) we have shown that salivary glands are able to secrete a transgene-encoded protein into serum as well as saliva. This result and other published data suggest that salivary glands may be a useful target site for vectors encoding therapeutic proteins for systemic delivery. The aim of the present study was to assess in vivo if transgene-encoded secretory proteins follow distinct, polarized sorting pathways as has been shown to occur "classically" in cell biological studies in vitro. Four first-generation, E1-, type 5 recombinant adenoviruses were used to deliver different transgenes to a rat submandibular cell line in vitro or to rat submandibular glands in vivo. Subsequently, the secretory distribution of the encoded proteins was determined. Luciferase, which has no signal peptide, served as a cell-associated, negative control and was used to correct for any nonspecific secretory protein release from cells. The three remaining transgene products tested, human tissue kallikrein (hK1), human growth hormone (hGH), and human alpha1-antitrypsin (halpha1AT), were predominantly secreted (>96%) in vitro. Most importantly, in vivo, after a parasympathomimetic secretory stimulus, both hK1 and hGH were secreted primarily in an exocrine manner into saliva. Conversely, halpha1AT was predominantly secreted into the bloodstream, i.e., in an endocrine manner. The aggregate results are consistent with the recognition of signals encoded within the transgenes that result in specific patterns of polarized protein secretion from rat submandibular gland cells in vivo.
Collapse
Affiliation(s)
- B J Baum
- Gene Therapy and Therapeutics Branch, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD 20892, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Nowroozi N, Kim S, Segawa A, Warita H, Rice DH, Denny PC, Zernik JH. High levels of GM(1)-ganglioside and GM(1)-ganglioside beta-galactosidase in the parotid gland: a new model for secretory mechanisms of the parotid gland. Otolaryngol Clin North Am 1999; 32:779-91. [PMID: 10477786 DOI: 10.1016/s0030-6665(05)70172-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new model for the subcellular basis of parotid secretion is presented in this article. GM(1)-ganglioside, typically found in neural tissues, is shown to be abundant in the parotid gland. This ganglioside may play a central role in membrane turnover mechanisms underlying exocytosis/endocytosis in its role as a promoter of membrane fusion or a fusogen. The lysosome and lysosomal hydrolases also play a central role in this model in catabolism of GM(1)-ganglioside. Consequently, high levels of the lysosomal hydrolase acidic beta-galactosidase are demonstrated in the salivary gland. GM(1)-gangliosidosis of the parotid glands, as described in mice, appears to be the first single-gene heritable disease found so far in the salivary glands.
Collapse
Affiliation(s)
- N Nowroozi
- Departments of Orthodontics and Basic Sciences, University of Southern California School of Dentistry, Los Angeles, California, USA
| | | | | | | | | | | | | |
Collapse
|
38
|
Otani T, Chepilko SM, Grendell JH, Gorelick FS. Codistribution of TAP and the granule membrane protein GRAMP-92 in rat caerulein-induced pancreatitis. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:G999-G1009. [PMID: 9815030 DOI: 10.1152/ajpgi.1998.275.5.g999] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The pathological activation of zymogens within the pancreatic acinar cell plays a role in acute pancreatitis. To identify the processing site where activation occurs, antibodies to the trypsinogen activation peptide (TAP) were used in immunofluorescence studies using frozen sections from rat pancreas. Saline controls or animals receiving caerulein in amounts producing physiological levels of pancreatic stimulation demonstrated little or no TAP immunoreactivity. However, after caerulein hyperstimulation (5 micrograms. kg-1. h-1) for 30 min and the induction of pancreatitis, TAP immunoreactivity appeared in a vesicular, supranuclear compartment that demonstrated no overlap with zymogen granules. The number of vesicles and their size increased with time. After 60 min of hyperstimulation with caerulein, most of the TAP reactivity was localized within vacuoles >/=1 micrometer that demonstrated immunoreactivity for the granule membrane protein GRAMP-92, a marker for lysosomes and recycling endosomes. Pretreatment with the protease inhibitor FUT-175 blocked the appearance of TAP after hyperstimulation. These studies provide evidence that caerulein hyperstimulation stimulates trypsinogen processing to trypsin in distinct acinar cell compartments in a time-dependent manner.
Collapse
Affiliation(s)
- T Otani
- Department of Medicine and Cell Biology, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516, USA
| | | | | | | |
Collapse
|
39
|
Kalil AN, Sperb D, Lichtenfels E. EFEITO DA PILOCARPINA NA REGENERAÇÃO HEPÁTICA PÓS HEPATECTOMIA PARCIAL EM RATOS. Acta Cir Bras 1998. [DOI: 10.1590/s0102-86501998000400004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Com o objetivo de verificar se o uso da pilocarpina produz diferença na velocidade da regeneração hepática empreendemos um estudo experimental. Sabe-se que em ratos salivectomizados a regeneração do fígado fica diminuída. Sabe-se também que a pilocarpina aumenta a salivação destes animais. Na primeira etapa determinamos a dose de pilocarpina a ser utilizada. Na segunda etapa do projeto foram realizadas as hepatectomias ressecando em média 52,8% do fígado. Nossos resultados demonstraram que a pilocarpina diminui a perda de peso corporal total ao final de 48 horas pós hepatectomia parcial ( p=0,55 ) e também diminui o edema hepático durante sua regeneração (p= 0,11 ), mas observamos um peso maior do fígado em regeneração no grupo controle no primeiro dia (p= 0,016).
Collapse
|
40
|
Abstract
Protein secretion from rat parotid acinar cells occurs in both the absence and presence of secretory agonists. Release takes place by four pathways that are distinguished by combined examination of their timing following biosynthetic labeling, their relative composition of salivary proteins, and their sensitivity to secretagogue stimulation. Following pulse-labeling with a radioactive amino acid, two unstimulated export pathways are detected--a constitutive-like pathway that is coupled to maturation of secretory granules and the later unstimulated exocytosis of secretory granules. In both cases, protein release is insensitive to secretory antagonists. Two regulated secretory pathways are also detected. The major regulated pathway comprises stimulated exocytosis of secretory granules and requires application of beta-adrenergic agonists (> or = 1 microM). A newly discovered minor regulated pathway resembles the constitutive-like pathway in secretory composition but requires low-dose stimulation by either beta-adrenergic or cholinergic agonists. The latter pathway may provide a significant component of basal secretion by the parotid gland during periods between meals.
Collapse
Affiliation(s)
- J D Castle
- Department of Cell Biology, University of Virginia Health Sciences Center, Charlottesville 22908, USA.
| |
Collapse
|