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Chen X, Chen Y, Zhang Y, Zhang Y, Wang Y, Li Y, Sun Y, Meng G, Yang G, Li H. ZG16 impacts gut microbiota-associated intestinal inflammation and pulmonary mucosal function through bacterial metabolites. Int Immunopharmacol 2024; 141:112995. [PMID: 39191121 DOI: 10.1016/j.intimp.2024.112995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 07/04/2024] [Accepted: 08/19/2024] [Indexed: 08/29/2024]
Abstract
Zymogen granule 16 (ZG16) is a secretory glycoprotein found in zymogen granules, which also plays an important role in colorectal inflammation and cancer. Herein, a ZG16 gene knock-out (ZG16-/-) mouse line was established and we found that ZG16 deletion damaged the intestinal mucosal barrier and gut microbiota, which resulted in low-level inflammation and further promoted the development of ulcerative colitis and inflammation-related colorectal cancer. Meanwhile, a metabolomics analysis on mouse feces showed that the metabolites significantly differed between ZG16-/- and WT mice, which were important mediators of host-microbiota communication and may impact the pulmonary inflammation of mice. Indeed, ZG16-/- mice showed more severe inflammation in a bronchial asthma model. Taken together, the results demonstrate that ZG16 plays a pivotal role in inhibiting inflammation and regulating immune responses in colorectum and lung of experimental animals, which may provide a better understanding of the underlying mechanism of human inflammatory diseases associated with ZG16.
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Affiliation(s)
- Xinping Chen
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, PR China
| | - Yixin Chen
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, PR China
| | - Ying Zhang
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, PR China
| | - Yonghuan Zhang
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, PR China
| | - Yao Wang
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, PR China
| | - Yingjia Li
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, PR China
| | - Yaqi Sun
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, PR China
| | - Guangxun Meng
- The Center for Microbes, Development, and Health, CAS Key Laboratory of Molecular Virology & Immunology, Shanghai Institute of Immunity and Infection, University of Chinese Academy of Sciences, Shanghai 200031, PR China.
| | - Guiwen Yang
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, PR China.
| | - Hua Li
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, PR China; The Center for Microbes, Development, and Health, CAS Key Laboratory of Molecular Virology & Immunology, Shanghai Institute of Immunity and Infection, University of Chinese Academy of Sciences, Shanghai 200031, PR China.
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2
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Mareninova OA, Vegh ET, Shalbueva N, Wightman CJ, Dillon DL, Malla S, Xie Y, Takahashi T, Rakonczay Z, French SW, Gaisano HY, Gorelick FS, Pandol SJ, Bensinger SJ, Davidson NO, Dawson DW, Gukovsky I, Gukovskaya AS. Dysregulation of mannose-6-phosphate-dependent cholesterol homeostasis in acinar cells mediates pancreatitis. J Clin Invest 2021; 131:146870. [PMID: 34128834 PMCID: PMC8321573 DOI: 10.1172/jci146870] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 06/11/2021] [Indexed: 01/18/2023] Open
Abstract
Disordered lysosomal/autophagy pathways initiate and drive pancreatitis, but the underlying mechanisms and links to disease pathology are poorly understood. Here, we show that the mannose-6-phosphate (M6P) pathway of hydrolase delivery to lysosomes critically regulates pancreatic acinar cell cholesterol metabolism. Ablation of the Gnptab gene encoding a key enzyme in the M6P pathway disrupted acinar cell cholesterol turnover, causing accumulation of nonesterified cholesterol in lysosomes/autolysosomes, its depletion in the plasma membrane, and upregulation of cholesterol synthesis and uptake. We found similar dysregulation of acinar cell cholesterol, and a decrease in GNPTAB levels, in both WT experimental pancreatitis and human disease. The mechanisms mediating pancreatic cholesterol dyshomeostasis in Gnptab-/- and experimental models involve a disordered endolysosomal system, resulting in impaired cholesterol transport through lysosomes and blockage of autophagic flux. By contrast, in Gnptab-/- liver the endolysosomal system and cholesterol homeostasis were largely unaffected. Gnptab-/- mice developed spontaneous pancreatitis. Normalization of cholesterol metabolism by pharmacologic means alleviated responses of experimental pancreatitis, particularly trypsinogen activation, the disease hallmark. The results reveal the essential role of the M6P pathway in maintaining exocrine pancreas homeostasis and function, and implicate cholesterol disordering in the pathogenesis of pancreatitis.
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Affiliation(s)
- Olga A. Mareninova
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Eszter T. Vegh
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Department of Pathophysiology, University of Szeged, Szeged, Hungary
| | - Natalia Shalbueva
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Carli J.M. Wightman
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Dustin L. Dillon
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Sudarshan Malla
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Yan Xie
- Division of Gastroenterology, Washington University School of Medicine, St. Louis, Missouri, USA
| | | | - Zoltan Rakonczay
- Department of Pathophysiology, University of Szeged, Szeged, Hungary
| | - Samuel W. French
- Department of Pathology, Harbor-UCLA Medical Center, Torrance, California, USA
| | | | - Fred S. Gorelick
- Departments of Cell Biology and Internal Medicine, Yale University School of Medicine and VA West Haven, West Haven, Connecticut, USA
| | - Stephen J. Pandol
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | | | - Nicholas O. Davidson
- Division of Gastroenterology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - David W. Dawson
- Department of Pathology and Laboratory Medicine and Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Ilya Gukovsky
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Anna S. Gukovskaya
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
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3
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Yasuno K, Igura S, Yamaguchi Y, Imaoka M, Kai K, Mori K. Pathological examination of spontaneous vacuolation of pancreatic acinar cells in mice. J Toxicol Pathol 2019; 32:105-109. [PMID: 31092977 PMCID: PMC6511541 DOI: 10.1293/tox.2018-0065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 01/15/2019] [Indexed: 12/18/2022] Open
Abstract
Pancreatic acinar cell vacuolation is spontaneously observed in mice; however, the lesion is rare and has not been well documented. Herein, we present a detailed pathological examination of this lesion. Vacuoles in pancreatic acinar cells were present in 2/15 X gene knockout mice with a C57BL/6J mouse background, 4/298 ICR(CD-1) mice, 1/110 B6C3F1 mice, and 3/399 CByB6F1-Tg(HRAS)2Jic mice. The vacuoles were usually observed in a unit of the acinus, and the lesions were spread throughout the pancreas. These vacuoles contained weakly basophilic material that was positive for the periodic acid-Schiff reaction. Immunohistochemically, the vacuoles were positive for calreticulin antibody. Electron microscopy revealed globular dilatation of the rough endoplasmic reticulum (rER). According to these findings, vacuolation of pancreatic acinar cells is caused by the accumulation of misfolded proteins and enlargement of the rER.
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Affiliation(s)
- Kyohei Yasuno
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
| | - Saori Igura
- Pathology Department, BoZo Research Center Inc, Gotemba-shi, Shizuoka 412-0039, Japan
| | - Yuko Yamaguchi
- Pathology Department, BoZo Research Center Inc, Gotemba-shi, Shizuoka 412-0039, Japan
| | - Masako Imaoka
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
| | - Kiyonori Kai
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
| | - Kazuhiko Mori
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
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4
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Mito A, Nakano Y, Saitoh T, Gouraud SSS, Yamaguchi Y, Sato T, Sasaki N, Kojima-Aikawa K. Lectin ZG16p inhibits proliferation of human colorectal cancer cells via its carbohydrate-binding sites. Glycobiology 2018; 28:21-31. [PMID: 29069492 DOI: 10.1093/glycob/cwx088] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 10/19/2017] [Indexed: 12/19/2022] Open
Abstract
Zymogen granule protein 16 (ZG16p) is a soluble lectin that binds to both mannose and heparin/heparan sulfate. It is highly expressed in the human digestive tract and is secreted into the mucus. In this study, we investigated the effect of ZG16p on the proliferation of human colorectal cancer cells. Overexpression of ZG16p in Caco-2 cells decreased cell growth. Recombinant ZG16p markedly inhibited proliferation of Caco-2, LS174T, HCT116 and HCT15 cells. Caco-2 cell growth was not inhibited by two mutated ZG16p proteins, D151A and M5 (K36A, R37A, R53A, R55A and R79A) lacking mannose- and heparin-binding activities, respectively. Immunofluorescent cell staining revealed that ZG16p-D151A maintained its binding to the Caco-2 cell surface, whereas ZG16p-M5 failed to bind to the cells. These results suggest that ZG16p interacts with the cell surface via basic amino acids substituted in ZG16p-M5 and inhibits Caco-2 cell proliferation via Asp151. In addition, growth of patient-derived colorectal tumor organoids in a 3D intestinal stem cell system was suppressed by ZG16p but not by ZG16p-M5. Taken together, our findings indicate that ZG16p inhibits the growth of colorectal cancer cells via its carbohydrate-binding sites in vitro and ex vivo. In this study, a novel pathway in cancer cell growth regulation through cell surface carbohydrate chains is suggested.
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Affiliation(s)
- Akiko Mito
- Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan.,Program for Leading Graduate Schools, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Yukiko Nakano
- Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Takako Saitoh
- Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Sabine S S Gouraud
- Leading Graduate School Promotion Center, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Yoshiki Yamaguchi
- Structure Glycobiology Team, Systems Glycobiology Research Group, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Toshiro Sato
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Nobuo Sasaki
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Kyoko Kojima-Aikawa
- Natural Science Division, Faculty of Core Research, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan.,Institute for Human Life Innovation, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
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5
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Possible Role of Phosphatidylcholine and Sphingomyelin on Fumonisin B1-mediated Toxicity. Food Saf (Tokyo) 2017; 5:75-97. [PMID: 32231933 DOI: 10.14252/foodsafetyfscj.2017004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/29/2017] [Indexed: 12/21/2022] Open
Abstract
A major corn-related mycotoxin, fumonisin B1 (FB1), continues to attract attention of researchers as well as risk-assessors due to the diverse toxicological characteristics, including distinct target tissues in different animal species and opposite susceptibility in males and females in mice and rats. More than thirty years passed since the structure identification as a sphingoid-like chemical, but the causal mechanism of the toxicity remains obscure in spites of extensive studies. Considerable amounts of knowledge have been accumulated on the biochemical/toxicological actions of FB1, but the influence on lipid dynamics and mobilization in the body has not been focused well in relation to the FB1-mediated toxicity. Considerable influences of this toxin on mobilization of sphingolipids and phospholipids and also on adaptive changes in their compositions in tissues are implicated from recent studies on FB1-interacting ceramide synthases. Accumulated patho-physiological data also suggest a possible role of hepatic phospholipid on FB1-mediated toxicity. Thus, a mechanism of FB1-mediated toxicity is discussed in relation to the mobilization of phospholipids and sphingolipids in the body in this context.
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6
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Satoh K, Narita T, Katsumata-Kato O, Sugiya H, Seo Y. Involvement of myristoylated alanine-rich C kinase substrate phosphorylation and translocation in cholecystokinin-induced amylase release in rat pancreatic acini. Am J Physiol Gastrointest Liver Physiol 2016; 310:G399-409. [PMID: 26744470 DOI: 10.1152/ajpgi.00198.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 01/05/2016] [Indexed: 01/31/2023]
Abstract
Cholecystokinin (CCK) is a gastrointestinal hormone that induces exocytotic amylase release in pancreatic acinar cells. The activation of protein kinase C (PKC) is involved in the CCK-induced pancreatic amylase release. Myristoylated alanine-rich C kinase substrate (MARCKS) is a ubiquitously expressed substrate of PKC. MARCKS has been implicated in membrane trafficking in several cell types. The phosphorylation of MARCKS by PKC results in the translocation of MARCKS from the membrane to the cytosol. Here, we studied the involvement of MARCKS in the CCK-induced amylase release in rat pancreatic acini. Employing Western blotting, we detected MARCKS protein in the rat pancreatic acini. CCK induced MARCKS phosphorylation. A PKC-δ inhibitor, rottlerin, inhibited the CCK-induced MARCKS phosphorylation and amylase release. In the translocation assay, we also observed CCK-induced PKC-δ activation. An immunohistochemistry study showed that CCK induced MARCKS translocation from the membrane to the cytosol. When acini were lysed by a detergent, Triton X-100, CCK partially induced displacement of the MARCKS from the GM1a-rich detergent-resistant membrane fractions (DRMs) in which Syntaxin2 is distributed. A MARCKS-related peptide inhibited the CCK-induced amylase release. These findings suggest that MARCKS phosphorylation by PKC-δ and then MARCKS translocation from the GM1a-rich DRMs to the cytosol are involved in the CCK-induced amylase release in pancreatic acinar cells.
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Affiliation(s)
- Keitaro Satoh
- Department of Regulatory Physiology, Dokkyo Medical University School of Medicine, Tochigi, Japan;
| | - Takanori Narita
- Laboratory of Veterinary Biochemistry, Nihon University College of Bioresource Sciences, Kanagawa, Japan
| | - Osamu Katsumata-Kato
- Department of Physiology, Nihon University School of Dentistry at Matsudo, Chiba, Japan
| | - Hiroshi Sugiya
- Laboratory of Veterinary Biochemistry, Nihon University College of Bioresource Sciences, Kanagawa, Japan
| | - Yoshiteru Seo
- Department of Regulatory Physiology, Dokkyo Medical University School of Medicine, Tochigi, Japan
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7
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Hanashima S, Götze S, Liu Y, Ikeda A, Kojima-Aikawa K, Taniguchi N, Varón Silva D, Feizi T, Seeberger PH, Yamaguchi Y. Defining the Interaction of Human Soluble Lectin ZG16p and Mycobacterial Phosphatidylinositol Mannosides. Chembiochem 2015; 16:1502-11. [PMID: 25919894 PMCID: PMC5896728 DOI: 10.1002/cbic.201500103] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Indexed: 11/11/2022]
Abstract
ZG16p is a soluble mammalian lectin that interacts with mannose and heparan sulfate. Here we describe detailed analysis of the interaction of human ZG16p with mycobacterial phosphatidylinositol mannosides (PIMs) by glycan microarray and NMR. Pathogen-related glycan microarray analysis identified phosphatidylinositol mono- and di-mannosides (PIM1 and PIM2) as novel ligand candidates of ZG16p. Saturation transfer difference (STD) NMR and transferred NOE experiments with chemically synthesized PIM glycans indicate that PIMs preferentially interact with ZG16p by using the mannose residues. The binding site of PIM was identified by chemical-shift perturbation experiments with uniformly (15)N-labeled ZG16p. NMR results with docking simulations suggest a binding mode of ZG16p and PIM glycan; this will help to elucidate the physiological role of ZG16p.
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Affiliation(s)
- Shinya Hanashima
- Structural Glycobiology Team, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, RIKEN Global Research Cluster, Wako, Saitama 351-0198 (Japan)
| | - Sebastian Götze
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam (Germany)
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195 Berlin (Germany)
| | - Yan Liu
- Glycosciences Laboratory, Department of Medicine, Imperial College London, Du Cane Road, London W12 0NN (UK)
| | - Akemi Ikeda
- Structural Glycobiology Team, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, RIKEN Global Research Cluster, Wako, Saitama 351-0198 (Japan)
| | - Kyoko Kojima-Aikawa
- The Glycoscience Institute, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo 112-8610 (Japan)
| | - Naoyuki Taniguchi
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, RIKEN Global Research Cluster, Wako, Saitama 351-0198 (Japan)
| | - Daniel Varón Silva
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam (Germany)
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195 Berlin (Germany)
| | - Ten Feizi
- Glycosciences Laboratory, Department of Medicine, Imperial College London, Du Cane Road, London W12 0NN (UK)
| | - Peter H Seeberger
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam (Germany)
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195 Berlin (Germany)
| | - Yoshiki Yamaguchi
- Structural Glycobiology Team, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, RIKEN Global Research Cluster, Wako, Saitama 351-0198 (Japan).
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8
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Aroso M, Agricola B, Hacker C, Schrader M. Proteoglycans support proper granule formation in pancreatic acinar cells. Histochem Cell Biol 2015; 144:331-46. [PMID: 26105026 DOI: 10.1007/s00418-015-1339-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2015] [Indexed: 12/31/2022]
Abstract
Zymogen granules (ZG) are specialized organelles in the exocrine pancreas which allow digestive enzyme storage and regulated secretion. The molecular mechanisms of their biogenesis and the sorting of zymogens are still incompletely understood. Here, we investigated the role of proteoglycans in granule formation and secretion of zymogens in pancreatic AR42J cells, an acinar model system. Cupromeronic Blue cytochemistry and biochemical studies revealed an association of proteoglycans primarily with the granule membrane. Removal of proteoglycans by carbonate treatment led to a loss of membrane curvature indicating a supportive role in the maintenance of membrane shape and stability. Chemical inhibition of proteoglycan synthesis impaired the formation of normal electron-dense granules in AR42J cells and resulted in the formation of unusually small granule structures. These structures still contained the zymogen carboxypeptidase, a cargo molecule of secretory granules, but migrated to lighter fractions after density gradient centrifugation. Furthermore, the basal secretion of amylase was increased in AR42J cells after inhibitor treatment. In addition, irregular-shaped granules appeared in pancreatic lobules. We conclude that the assembly of a proteoglycan scaffold at the ZG membrane is supporting efficient packaging of zymogens and the proper formation of stimulus-competent storage granules in acinar cells of the pancreas.
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Affiliation(s)
- Miguel Aroso
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Brigitte Agricola
- Department of Cell Biology and Cell Pathology, University of Marburg, 35037, Marburg, Germany
| | - Christian Hacker
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Michael Schrader
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal. .,College of Life and Environmental Sciences, Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
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9
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Fox RM, Andrew DJ. Changes in organelle position and epithelial architecture associated with loss of CrebA. Biol Open 2015; 4:317-30. [PMID: 25681391 PMCID: PMC4359738 DOI: 10.1242/bio.201411205] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Drosophila CrebA facilitates high-level secretion by transcriptional upregulation of the protein components of the core secretory machinery. In CrebA mutant embryos, both salivary gland (SG) morphology and epidermal cuticle secretion are abnormal, phenotypes similar to those observed with mutations in core secretory pathway component genes. Here, we examine the cellular defects associated with CrebA loss in the SG epithelium. Apically localized secretory vesicles are smaller and less abundant, consistent with overall reductions in secretion. Unexpectedly, global mislocalization of cellular organelles and excess membrane accumulation in the septate junctions (SJs) are also observed. Whereas mutations in core secretory pathway genes lead to organelle localization defects similar to those of CrebA mutants, they have no effect on SJ-associated membrane. Mutations in tetraspanin genes, which are normally repressed by CrebA, have mild defects in SJ morphology that are rescued by simultaneous CrebA loss. Correspondingly, removal of several tetraspanins gives partial rescue of the CrebA SJ phenotype, supporting a role for tetraspanins in SJ organization.
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Affiliation(s)
- Rebecca M Fox
- The Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Deborah J Andrew
- The Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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10
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Xu C, Wang BC, Yu Z, Sun M. Structural insights into Bacillus thuringiensis Cry, Cyt and parasporin toxins. Toxins (Basel) 2014; 6:2732-70. [PMID: 25229189 PMCID: PMC4179158 DOI: 10.3390/toxins6092732] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/26/2014] [Accepted: 08/28/2014] [Indexed: 11/30/2022] Open
Abstract
Since the first X-ray structure of Cry3Aa was revealed in 1991, numerous structures of B. thuringiensis toxins have been determined and published. In recent years, functional studies on the mode of action and resistance mechanism have been proposed, which notably promoted the developments of biological insecticides and insect-resistant transgenic crops. With the exploration of known pore-forming toxins (PFTs) structures, similarities between PFTs and B. thuringiensis toxins have provided great insights into receptor binding interactions and conformational changes from water-soluble to membrane pore-forming state of B. thuringiensis toxins. This review mainly focuses on the latest discoveries of the toxin working mechanism, with the emphasis on structural related progress. Based on the structural features, B. thuringiensis Cry, Cyt and parasporin toxins could be divided into three categories: three-domain type α-PFTs, Cyt toxin type β-PFTs and aerolysin type β-PFTs. Structures from each group are elucidated and discussed in relation to the latest data, respectively.
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Affiliation(s)
- Chengchen Xu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Bi-Cheng Wang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
| | - Ziniu Yu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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11
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Craciun C. Porosome in the Exocrine Pancreas: A Detailed EM Study suppressor. Discoveries (Craiova) 2014; 2:e23. [PMID: 32309552 PMCID: PMC6941546 DOI: 10.15190/d.2014.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A major question in cell biology that accumulation of partially empty vesicles in cells following secretion is seen, while it is believed that secretion occurs via the complete merger of secretory vesicles with the cell plasma membrane. This important question was solved nearly two decades ago, with the discovery of the Porosome. Porosomes are cup-shaped lipoprotein structures found at the plasma membrane of all cells. Secretory vesicles dock and transiently fuse at the porosome base to form a continuous channel or fusion pore to release the pressurized vesicle contents to the outside. In a decade-long study by our group, we carefully examined using electron microscopy, the detailed structure of the porosome complex in acinar cells of the exocrine pancreas. Besides conformation of earlier findings, our study provides in much greater detail, the in situ morphology of the porosome complex in the exocrine pancreas. The discovery of the detailed morphology of the exocrine pancreas porosome complex in my laboratory is one of the major highlights of my academic career spanning nearly 50 years. Results from our EM studies, reveal for the first time the presence of tethers or cables, which are likely t-SNAREs, present at the porosome base. These EM studies further demonstrate for the first time the docking of a single secretory vesicle or zymogen granule at the base of more than one porosome complex. Detailed spoke-like elements lining the porosome cup were also observed for the first time in these studies, greatly advancing our understanding of the molecular architecture and physiology of the porosome in the exocrine pancreas.
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Kanagawa M, Liu Y, Hanashima S, Ikeda A, Chai W, Nakano Y, Kojima-Aikawa K, Feizi T, Yamaguchi Y. Structural basis for multiple sugar recognition of Jacalin-related human ZG16p lectin. J Biol Chem 2014; 289:16954-65. [PMID: 24790092 PMCID: PMC4059138 DOI: 10.1074/jbc.m113.539114] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
ZG16p is a soluble mammalian lectin, the first to be described with a Jacalin-related β-prism-fold. ZG16p has been reported to bind both to glycosaminoglycans and mannose. To determine the structural basis of the multiple sugar-binding properties, we conducted glycan microarray analyses of human ZG16p. We observed that ZG16p preferentially binds to α-mannose-terminating short glycans such as Ser/Thr-linked O-mannose, but not to high mannose-type N-glycans. Among sulfated glycosaminoglycan oligomers examined, chondroitin sulfate B and heparin oligosaccharides showed significant binding. Crystallographic studies of human ZG16p lectin in the presence of selected ligands revealed the mechanism of multiple sugar recognition. Manα1–3Man and Glcβ1–3Glc bound in different orientations: the nonreducing end of the former and the reducing end of the latter fitted in the canonical shallow mannose binding pocket. Solution NMR analysis using 15N-labeled ZG16p defined the heparin-binding region, which is on an adjacent flat surface of the protein. On-array competitive binding assays suggest that it is possible for ZG16p to bind simultaneously to both types of ligands. Recognition of a broad spectrum of ligands by ZG16p may account for the multiple functions of this lectin in the formation of zymogen granules via glycosaminoglycan binding, and in the recognition of pathogens in the digestive system through α-mannose-related recognition.
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Affiliation(s)
- Mayumi Kanagawa
- From the Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yan Liu
- the Department of Medicine, Glycosciences Laboratory, Imperial College London, Burlington Danes Building, Du Cane Road, London W12 0NN, United Kingdom,
| | - Shinya Hanashima
- From the Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Akemi Ikeda
- From the Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Wengang Chai
- the Department of Medicine, Glycosciences Laboratory, Imperial College London, Burlington Danes Building, Du Cane Road, London W12 0NN, United Kingdom
| | - Yukiko Nakano
- the Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan, and the The Glycoscience Institute, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Kyoko Kojima-Aikawa
- the Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan, and the The Glycoscience Institute, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Ten Feizi
- the Department of Medicine, Glycosciences Laboratory, Imperial College London, Burlington Danes Building, Du Cane Road, London W12 0NN, United Kingdom
| | - Yoshiki Yamaguchi
- From the Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan,
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Gómez-Lázaro M, Rinn C, Aroso M, Amado F, Schrader M. Proteomic analysis of zymogen granules. Expert Rev Proteomics 2014; 7:735-47. [DOI: 10.1586/epr.10.31] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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14
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Modulating zymogen granule formation in pancreatic AR42J cells. Exp Cell Res 2012; 318:1855-66. [PMID: 22683857 DOI: 10.1016/j.yexcr.2012.05.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 05/11/2012] [Accepted: 05/24/2012] [Indexed: 01/07/2023]
Abstract
Zymogen granules (ZG) are specialized organelles in the exocrine pancreas which allow digestive enzyme storage and regulated secretion. To investigate ZG biogenesis, cargo sorting and packaging, suitable cellular model systems are required. Here, we demonstrate that granule formation in pancreatic AR42J cells, an acinar model system, can be modulated by altering the growth conditions in cell culture. We find that cultivation of AR42J cells in Panserin™ 401, a serum-free medium, enhances the induction of granule formation in the presence or absence of dexamethasone when compared to standard conditions including serum. Biochemical and morphological studies revealed an increase in ZG markers on the mRNA and protein level, as well as in granule size compared to standard conditions. Our data indicate that this effect is related to pronounced differentiation of AR42J cells. To address if enhanced expression of ZG proteins promotes granule formation, we expressed several zymogens and ZG membrane proteins in unstimulated AR42J cells and in constitutively secreting COS-7 cells. Neither single expression nor co-expression was sufficient to initiate granule formation in AR42J cells or the formation of granule-like structures in COS-7 cells as described for neuroendocrine cargo proteins. The importance of our findings for granule formation in exocrine cells is discussed.
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Inder KL, Zheng YZ, Davis MJ, Moon H, Loo D, Nguyen H, Clements JA, Parton RG, Foster LJ, Hill MM. Expression of PTRF in PC-3 Cells modulates cholesterol dynamics and the actin cytoskeleton impacting secretion pathways. Mol Cell Proteomics 2012; 11:M111.012245. [PMID: 22030351 PMCID: PMC3277761 DOI: 10.1074/mcp.m111.012245] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 10/23/2011] [Indexed: 01/08/2023] Open
Abstract
Expression of caveolin-1 is up-regulated in prostate cancer metastasis and is associated with aggressive recurrence of the disease. Intriguingly, caveolin-1 is also secreted from prostate cancer cell lines and has been identified in secreted prostasomes. Caveolin-1 is the major structural component of the plasma membrane invaginations called caveolae. Co-expression of the coat protein Polymerase I and transcript release factor (PTRF) is required for caveolae formation. We recently found that expression of caveolin-1 in the aggressive prostate cancer cell line PC-3 is not accompanied by PTRF, leading to noncaveolar caveolin-1 lipid rafts. Moreover, ectopic expression of PTRF in PC-3 cells sequesters caveolin-1 into caveolae. Here we quantitatively analyzed the effect of PTRF expression on the PC-3 proteome using stable isotope labeling by amino acids in culture and subcellular proteomics. We show that PTRF reduced the secretion of a subset of proteins including secreted proteases, cytokines, and growth regulatory proteins, partly via a reduction in prostasome secretion. To determine the cellular mechanism accounting for the observed reduction in secreted proteins we analyzed total membrane and the detergent-resistant membrane fractions. Our data show that PTRF expression selectively impaired the recruitment of actin cytoskeletal proteins to the detergent-resistant membrane, which correlated with altered cholesterol distribution in PC-3 cells expressing PTRF. Consistent with this, modulating cellular cholesterol altered the actin cytoskeleton and protein secretion in PC-3 cells. Intriguingly, several proteins that function in ER to Golgi trafficking were reduced by PTRF expression. Taken together, these results suggest that the noncaveolar caveolin-1 found in prostate cancer cells generates a lipid raft microenvironment that accentuates secretion pathways, possibly at the step of ER sorting/exit. Importantly, these effects could be modulated by PTRF expression.
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Affiliation(s)
- Kerry L. Inder
- From the ‡The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Queensland 4102, Australia
| | - Yu Zi Zheng
- From the ‡The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Queensland 4102, Australia
- §Centre for High-Throughput Biology and Department of Biochemistry and Molecular Biology, 2125 East Mall, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Melissa J. Davis
- ¶Queensland Facility for Advanced Bioinformatics, Brisbane, Queensland 4072, Australia
- **The University of Queensland Institute for Molecular Bioscience, Brisbane, Queensland 4072, Australia
| | - Hyeongsun Moon
- From the ‡The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Queensland 4102, Australia
| | - Dorothy Loo
- From the ‡The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Queensland 4102, Australia
| | - Hien Nguyen
- From the ‡The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Queensland 4102, Australia
| | - Judith A. Clements
- ‖Australian Prostate Cancer Research Centre –Queensland, Institute for Molecular Bioscience, The University of Queensland, University of Technology, Brisbane, Queensland 4059, Australia
| | - Robert G. Parton
- **The University of Queensland Institute for Molecular Bioscience, Brisbane, Queensland 4072, Australia
| | - Leonard J. Foster
- §Centre for High-Throughput Biology and Department of Biochemistry and Molecular Biology, 2125 East Mall, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Michelle M. Hill
- From the ‡The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Queensland 4102, Australia
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Kumazawa-Inoue K, Mimura T, Hosokawa-Tamiya S, Nakano Y, Dohmae N, Kinoshita-Toyoda A, Toyoda H, Kojima-Aikawa K. ZG16p, an animal homolog of β-prism fold plant lectins, interacts with heparan sulfate proteoglycans in pancreatic zymogen granules. Glycobiology 2011; 22:258-66. [DOI: 10.1093/glycob/cwr145] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Role of Gangliosides and Plasma Membrane-Associated Sialidase in the Process of Cell Membrane Organization. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 705:297-316. [DOI: 10.1007/978-1-4419-7877-6_14] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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The zymogen granule protein 2 (GP2) binds to scavenger receptor expressed on endothelial cells I (SREC-I). Cell Immunol 2010; 267:88-93. [PMID: 21190681 PMCID: PMC3040788 DOI: 10.1016/j.cellimm.2010.12.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 11/29/2010] [Accepted: 12/02/2010] [Indexed: 12/11/2022]
Abstract
The pancreatic zymogen granule membrane protein (GP2) is expressed by pancreatic acinar cells and M cells of the ileum. GP2 is the closest related homologue of the urine resident Tamm-Horsfall protein (THP). Recently, it was shown that THP is a ligand of various scavenger receptors (SRs). Therefore, we were interested, if GP2 has similar properties. cDNA of different SRs was stably transfected into a murine thymoma cell line. GP2 was recombinantly expressed, purified and biotinylated. Binding or uptake of GP2 by transfected cells or monocyte-derived dendritic cells (moDCs) was analyzed by flow-cytometry. GP2 is a binding partner of the scavenger receptor expressed on endothelial cells I (SREC-I) but not of SR-AI and SR-BI. The dissociation constant (K(d)) of GP2 binding to SREC-I is 41.3nM. SREC transfected cells are able to internalize GP2. moDCs express SREC-I and also bind and internalize GP2. Inhibition of SREC-I on moDCs with anti-SREC-I antibodies does not result in a decreased GP2 binding. Interaction of GP2 with SREC-I and uptake might have profound effects in antigen clearance and mediation of the immune response. In addition to SREC-I other presently unknown receptors for GP2 on DCs might be involved in this process.
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Bonekamp NA, Vormund K, Jacob R, Schrader M. Dynamin-like protein 1 at the Golgi complex: A novel component of the sorting/targeting machinery en route to the plasma membrane. Exp Cell Res 2010; 316:3454-67. [DOI: 10.1016/j.yexcr.2010.07.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2010] [Revised: 07/25/2010] [Accepted: 07/29/2010] [Indexed: 12/23/2022]
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Crystal structures of human secretory proteins ZG16p and ZG16b reveal a Jacalin-related β-prism fold. Biochem Biophys Res Commun 2010; 404:201-5. [PMID: 21110947 DOI: 10.1016/j.bbrc.2010.11.093] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2010] [Accepted: 11/22/2010] [Indexed: 11/24/2022]
Abstract
ZG16p is a secretory protein that mediates condensation-sorting of pancreatic enzymes to the zymogen granule membrane in pancreatic acinar cells. ZG16p interacts with glycosaminoglycans and the binding is considered to be important for condensation-sorting of pancreatic enzymes. ZG16b/PAUF, a paralog of ZG16p, has recently been found to play a role in gene regulation and cancer metastasis. However, the detailed functions of ZG16p and ZG16b remain to be clarified. Here, in order to obtain insights into structure-function relationships, we conducted crystallographic studies of human ZG16p lectin as well as its paralog, ZG16b, and determined their crystal structures at 1.65 and 2.75 Å resolution, respectively. ZG16p has a Jacalin-related β-prism fold, the first to be reported among mammalian lectins. The putative sugar-binding site of ZG16p is occupied by a glycerol molecule, mimicking the mannose bound to Jacalin-related mannose-binding-type plant lectins such as Banlec. ZG16b also has a β-prism fold, but some amino acid residues of the putative sugar-binding site differ from those of the mannose-type binding site suggesting altered preference. A positively charged patch, which may bind sulfated groups of the glycosaminoglycans, is located around the putative sugar-binding site of ZG16p and ZG16b. Taken together, we suggest that the sugar-binding site and the adjacent basic patch of ZG16p and ZG16b cooperatively form a functional glycosaminoglycan-binding site.
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21
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Borta H, Aroso M, Rinn C, Gomez-Lazaro M, Vitorino R, Zeuschner D, Grabenbauer M, Amado F, Schrader M. Analysis of low abundance membrane-associated proteins from rat pancreatic zymogen granules. J Proteome Res 2010; 9:4927-39. [PMID: 20707389 DOI: 10.1021/pr100052q] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Zymogen granules (ZG) are specialized storage organelles in the exocrine pancreas that allow the sorting, packaging, and regulated apical secretion of digestive enzymes. As there is a critical need for further understanding of the key processes in regulated secretion to develop new therapeutic options in medicine, we applied a suborganellar proteomics approach to identify peripheral membrane-associated ZG proteins. We focused on the analysis of a "basic" group (pH range 6.2-11) with about 46 spots among which 44 were identified by tandem mass spectrometry. These spots corresponded to 16 unique proteins, including rat mast cell chymase (RMCP-1) and peptidyl-prolyl cis-trans isomerase B (PpiB; cyclophilin B), an ER-resident protein. To confirm that these proteins were specific to zymogen granules and not contaminants of the preparation, we conducted a series of validation experiments. Immunoblotting of ZG subfractions revealed that chymase and PpiB behaved like bona fide peripheral membrane proteins. Their expression in rat pancreas was regulated by feeding behavior. Ultrastructural and immunofluorescence studies confirmed their ZG localization. Furthermore, a chymase-YFP fusion protein was properly targeted to ZG in pancreatic AR42J cells. Interestingly, for both proteins, proteoglycan-binding properties have been reported. The importance of our findings for sorting and packaging during ZG formation is discussed.
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Affiliation(s)
- Heike Borta
- Department of Cell Biology and Cell Pathology, Philipps University of Marburg, Robert Koch Strasse 6, Marburg, Germany
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Witt H, Rosendahl J, te Morsche RHM, Santhosh S, Chacko A, Schulz HU, Landt O, Teich N, Keim V, Mössner J, Gress TM, Ockenga J, Schmidt H, Kovacs P, Blüher M, Stumvoll M, Kage A, Groneberg DA, Jansen JBMJ, Nickel R, Drenth JPH. Mutational analysis of the gene encoding the zymogen granule membrane glycoprotein 2 (GP2) in patients with chronic pancreatitis. Pancreas 2010; 39:188-92. [PMID: 19959969 DOI: 10.1097/mpa.0b013e3181bd94ae] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVES Premature activation of pancreatic digestive enzymes is considered as a major factor in the pathogenesis of pancreatitis. Genetic alterations of different pancreatic zymogens or their inhibitors have been associated with chronic pancreatitis (CP). METHODS We sequenced all 12 GP2 exons in 380 German CP patients and in 182 German control subjects. In addition, we analyzed exon 3 of GP2 in 803 further CP patients and 1780 controls originating from Germany, the Netherlands, and India by targeted DNA sequencing. RESULTS We detected 12 nonsynonymous and 6 synonymous exonic variants. All nonsynonymous changes with exception of c.220C>T (p.R74X) and c.502_503delG (p.G168fsX174) in exon 3 and c.541C>T (p.R181X) in exon 4 were missense mutations and predominantly located in exon 3. All nonsynonymous variants were found in single cases only, with exception of 2 alterations, c.355A>G (p.M119V) and c.409G>A (p. A137T), both located in exon 3. To elucidate the role of these 2 exon 3 variants, we investigated additional patients and controls. The frequency of these variants was similar between patients and controls regardless of ethnic background or cause of CP. CONCLUSIONS Our data suggest that GP2 alterations do not alter the risk for the development of CP.
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Affiliation(s)
- Heiko Witt
- Department of Hepatology and Gastroenterology, Charité, Campus Virchow-Klinikum, Universitätsmedizin Berlin, Berlin, Germany.
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Faust F, Gomez-Lazaro M, Borta H, Agricola B, Schrader M. Rab8 is Involved in Zymogen Granule Formation in Pancreatic Acinar AR42J Cells. Traffic 2008; 9:964-79. [DOI: 10.1111/j.1600-0854.2008.00739.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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24
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Prinetti A, Chigorno V, Mauri L, Loberto N, Sonnino S. Modulation of cell functions by glycosphingolipid metabolic remodeling in the plasma membrane. J Neurochem 2007; 103 Suppl 1:113-25. [DOI: 10.1111/j.1471-4159.2007.04714.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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25
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Katsumata O, Fujita-Yoshigaki J, Hara-Yokoyama M, Yanagishita M, Furuyama S, Sugiya H. Syntaxin6 separates from GM1a-rich membrane microdomain during granule maturation. Biochem Biophys Res Commun 2007; 357:1071-7. [PMID: 17459336 DOI: 10.1016/j.bbrc.2007.04.053] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2007] [Accepted: 04/10/2007] [Indexed: 01/01/2023]
Abstract
Since it was reported that components of immature secretory granules (ISGs) are different from those of mature secretory granules (MSGs) in rat parotid acinar cells, we have been considering that components of secretory granules (SGs) change dynamically during granule maturation. As the first step to understand the mechanism of granule maturation, we separated low-density detergent-resistant membrane fractions (DRMs) from purified SGs of rat parotid gland. When SGs were lysed by the detergent Brij-58, syntaxin6 and VAMP4 were found in DRMs that were different from the GM1a-rich DRMs containing VAMP2. Because syntaxin6 and VAMP4 are known to be related to granule formation, we attempted to separate DRMs from ISGs. To enrich for ISGs, glands were removed from rats 5h after intraperitoneal injection of isoproterenol and used to purify the newly synthesized granules. Compared to mature granules prepared without injection, these newly formed granules were lower in density and contained higher concentrations of syntaxin6, VAMP4, and gamma-adaptin. This composition is consistent with the characterizations of ISGs. DRMs isolated from the newly formed granules were GM1a-rich and contained syntaxin6, VAMP4, and VAMP2 together. Thus, our findings suggest that syntaxin6 and VAMP4 associate with a GM1a-rich membrane microdomain during granule formation but enter a separate membrane microdomain before transport from granules during maturation.
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Affiliation(s)
- Osamu Katsumata
- Department of Physiology and Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho-Nishi, Matsudo, Chiba 271-8587, Japan
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Berkane AA, Nguyen HTT, Tranchida F, Waheed AA, Deyris V, Tchiakpe L, Fasano C, Nicoletti C, Desseaux V, Ajandouz EH, Comeau D, Comeau L, Hiol A. Proteomic of lipid rafts in the exocrine pancreas from diet-induced obese rats. Biochem Biophys Res Commun 2007; 355:813-9. [PMID: 17320817 DOI: 10.1016/j.bbrc.2007.02.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Accepted: 02/08/2007] [Indexed: 01/18/2023]
Abstract
In the present work, we induced obesity in rats with high-energy-starch diet and studied exocrine pancreas response. The zymogen granule (ZG) or purified plasma membrane (PM) from the exocrine pancreas was used for the isolation of the detergent-resistant membranes (DRMs). Based on high content of cholesterol, GM1, the bile salt dependent lipase (BSDL), and GP2 enrichment, the low-density fractions were defined as lipid rafts. Additionally, the rafts vesicles were determined by immunogold labeling with anti BSDL. By combining MALDI-TOF/MS and nano-LC ESI Q-TOF MS/MS proteomic identification we have selected 33 proteins from the lipid rafts which were classified into at least four functional families. Our data suggest that the acinar PM from the diet-induced obesity rats may be organized into lipid rafts, and characterization of rafts proteome can contribute to improve our understanding of food digestion under obesity.
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Affiliation(s)
- Amine Adda Berkane
- Université Paul Cézanne, FST-Institut Méditerranéen de Recherche en Nutrition IMRN, UMR INRA 1111/PNV UMR 6153 1147, Marseille, France
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27
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Coudreuse D, Korswagen HC. The making of Wnt: new insights into Wnt maturation, sorting and secretion. Development 2007; 134:3-12. [PMID: 17138665 DOI: 10.1242/dev.02699] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Damien Coudreuse
- Hubrecht Laboratory and Center for Biomedical Genetics, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
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Welker P, Geist B, Frühauf JH, Salanova M, Groneberg DA, Krause E, Bachmann S. Role of lipid rafts in membrane delivery of renal epithelial Na+-K+-ATPase, thick ascending limb. Am J Physiol Regul Integr Comp Physiol 2006; 292:R1328-37. [PMID: 17082358 DOI: 10.1152/ajpregu.00166.2006] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Lipid rafts are cholesterol- and shingolipid-enriched membrane microdomains implicated in membrane signaling and trafficking. To assess renal epithelial raft functions through the characterization of their associated membrane proteins, we have isolated lipid rafts from rat kidney by sucrose gradient fractionation after detergent treatment. The low-density fraction was enriched in cholesterol, sphingolipid, and flotillin-1 known as lipid raft markers. Based on proteomic analysis of the low-density fraction, the protein with the highest significance score was the alpha-subunit of Na(+)-K(+)-ATPase (NKA), whose raft association was validated by simultaneous immunoblotting. The beta-subunit of NKA was copurified from the low-density fraction. To test the role of lipid rafts in sorting and membrane delivery of renal-transporting epithelia, we have chosen to study thick ascending limb (TAL) epithelium for its high NKA activity and the property to be stimulated by antidiuretic hormone (ADH). Cultured rabbit TAL cells were studied. Cholesterol depletion and detergent extraction at warmth caused a shift of NKA to the higher-density fractions. Comparative preparations from blood monocytes revealed the absence of NKA from rafts in these nonpolarized cells. Short-term exposure of rabbit TAL cells to ADH (1 h) caused translocation and enhanced raft association of NKA via cAMP activation. Preceding cholesterol depletion prevented this effect. TAL-specific, glycosylphosphatidylinositol-anchored Tamm Horsfall protein was copurified with NKA in the same raft fraction, suggesting functional interference between these products. These results may have functional implications regarding the turnover, trafficking, and regulated surface expression of NKA as the major basolateral ion transporter of TAL.
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Affiliation(s)
- Pia Welker
- Center of Anatomy, Cardio-Renal-Unit, Charité Universitätsmedizin Berlin, Philippstrasse 12, 10115 Berlin, Germany.
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Chmelar RS, Nathanson NM. Identification of a novel apical sorting motif and mechanism of targeting of the M2 muscarinic acetylcholine receptor. J Biol Chem 2006; 281:35381-96. [PMID: 16968700 DOI: 10.1074/jbc.m605954200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Previous studies have shown that the M2 receptor is localized at steady state to the apical domain in Madin-Darby canine kidney (MDCK) epithelial cells. In this study, we identify the molecular determinants governing the localization and the route of apical delivery of the M2 receptor. First, by confocal analysis of a transiently transfected glycosylation mutant in which the three putative glycosylation sites were mutated, we determined that N-glycans are not necessary for the apical targeting of the M2 receptor. Next, using a chimeric receptor strategy, we found that two independent sequences within the M2 third intracellular loop can confer apical targeting to the basolaterally targeted M4 receptor, Val270-Lys280 and Lys280-Ser350. Experiments using Triton X-100 extraction followed by OptiPrep density gradient centrifugation and cholera toxin beta-subunit-induced patching demonstrate that apical targeting is not because of association with lipid rafts. 35S-Metabolic labeling experiments with domain-specific surface biotinylation as well as immunocytochemical analysis of the time course of surface appearance of newly transfected confluent MDCK cells expressing FLAG-M2-GFP demonstrate that the M2 receptor achieves its apical localization after first appearing on the basolateral domain. Domain-specific application of tannic acid of newly transfected cells indicates that initial basolateral plasma membrane expression is required for subsequent apical localization. This is the first demonstration that a G-protein-coupled receptor achieves its apical localization in MDCK cells via transcytosis.
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Affiliation(s)
- Renée S Chmelar
- Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195-7750, USA
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Bach JP, Borta H, Ackermann W, Faust F, Borchers O, Schrader M. The secretory granule protein syncollin localizes to HL-60 cells and neutrophils. J Histochem Cytochem 2006; 54:877-88. [PMID: 16517980 DOI: 10.1369/jhc.5a6792.2006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The secretory granule protein syncollin was first identified in the exocrine pancreas where a population of the protein is associated with the luminal surface of the zymogen granule membrane. In this study we provide first morphological and biochemical evidence that, in addition to its pancreatic localization, syncollin is also present in neutrophilic granulocytes of rat and human origin. By immunohistological studies, syncollin was detected in neutrophilic granulocytes of the spleen. Furthermore, syncollin is expressed by the promyelocytic HL-60 cells, where it is stored in azurophilic granules and in a vesicular compartment. These findings were confirmed by fractionation experiments and immunoelectron microscopy. Treatment with a phorbol ester triggered the release of syncollin indicating that in HL-60 cells it is a secretory protein that can be mobilized upon stimulation. A putative role for syncollin in host defense is discussed.
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Affiliation(s)
- Jan-Philipp Bach
- Department of Cell Biology and Cell Pathology, University of Marburg, Robert-Koch Str. 6, D-35037 Marburg, Germany
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31
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Nguyen HTT, Amine AB, Lafitte D, Waheed AA, Nicoletti C, Villard C, Létisse M, Deyris V, Rozière M, Tchiakpe L, Danielle CD, Comeau L, Hiol A. Proteomic characterization of lipid rafts markers from the rat intestinal brush border. Biochem Biophys Res Commun 2006; 342:236-44. [PMID: 16480947 DOI: 10.1016/j.bbrc.2006.01.141] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Accepted: 01/26/2006] [Indexed: 11/22/2022]
Abstract
To assess intestinal lipid rafts functions through the characterization of their protein markers, we have isolated lipid rafts of rat mucosa either from the total membrane or purified brush-border membrane (BBM) by sucrose gradient fractionation after detergent treatment. In both membrane preparations, the floating fractions (4-5) were enriched in cholesterol, ganglioside GM1, and N aminopeptidase (NAP) known as intestinal lipid rafts markers. Based on MALDI-TOF/MS identification and simultaneous detection by immunoblotting, 12 proteins from BBM cleared from contaminants were selected as rafts markers. These proteins include several signaling/trafficking proteins belonging to the G protein family and the annexins as well as GPI-anchored proteins. Remarkably GP2, previously described as the pancreatic granule GPI-anchored protein, was found in intestinal lipid rafts. The proteomic strategy assayed on the intestine leads to the characterization of known (NAP, alkaline phosphatase, dipeptidyl aminopeptidase, annexin II, and galectin-4) and new (GP2, annexin IV, XIIIb, Galpha(q), Galpha(11), glutamate receptor, and GPCR 7) lipid rafts markers. Together our results indicate that some digestive enzymes, trafficking and signaling proteins may be functionally distributed in the intestine lipid rafts.
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Affiliation(s)
- Hang Thi Thu Nguyen
- Université Paul Cézanne, Aix-Marseille III, Faculté des Sciences et Techniques de St Jérôme, Institut Méditerranéen de Recherche en Nutrition IMRN, UMR-INRA 1111, LCBA-LBBN, 13397 Marseille Cedex 20, France
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32
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Marzesco AM, Janich P, Wilsch-Bräuninger M, Dubreuil V, Langenfeld K, Corbeil D, Huttner WB, Corbeil D. Release of extracellular membrane particles carrying the stem cell marker prominin-1 (CD133) from neural progenitors and other epithelial cells. J Cell Sci 2005; 583:897-902. [PMID: 15976444 DOI: 10.1016/j.febslet.2009.01.048] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Revised: 01/24/2009] [Accepted: 01/27/2009] [Indexed: 01/11/2023] Open
Abstract
Apical plasma membrane constituents of mammalian neural stem/progenitor cells have recently been implicated in maintaining their stem/progenitor cell state. Here, we report that in the developing embryonic mouse brain, the fluid in the lumen of the neural tube contains membrane particles carrying the stem cell marker prominin-1 (CD133), a pentaspan membrane protein found on membrane protrusions of the apical surface of neuroepithelial cells. Two size classes of prominin-1-containing membrane particles were observed in the ventricular fluid: approximately 600-nm particles, referred to as P2 particles, and 50-80-nm vesicles, referred to as P4 particles. The P2 and P4 particles appeared in the ventricular fluid at the very onset and during the early phase of neurogenesis, respectively. Concomitant with their appearance, the nature of the prominin-1-containing apical plasma membrane protrusions of neuroepithelial cells changed, in that microvilli were lost and large pleiomorphic protuberances appeared. P4 particles were found in various body fluids of adult humans, including saliva, seminal fluid and urine, and were released by the epithelial model cell line Caco-2 upon differentiation. Importantly, P4 particles were distinct from exosomes. Our results demonstrate the widespread occurrence of a novel class of extracellular membrane particles containing proteins characteristic of stem cells, and raise the possibility that the release of the corresponding membrane subdomains from the apical surface of neural progenitors and other epithelial cells may have a role in tissue development and maintenance. Moreover, the presence of prominin-1-containing membrane particles in human body fluids may provide the basis for a protein-based diagnosis of certain diseases.
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Affiliation(s)
- Anne-Marie Marzesco
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
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33
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Huang YP, Cheng J, Zhang SL, Wang L, Guo J, Liu Y, Yang Y, Zhang LY, Bai GQ, Gao XS, Ji D, Lin SM, Shao Q. Screening of hepatocyte proteins binding to F protein of hepatitis C virus by yeast two-hybrid system. World J Gastroenterol 2005; 11:5659-65. [PMID: 16237761 PMCID: PMC4481484 DOI: 10.3748/wjg.v11.i36.5659] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the biological function of F protein by yeast two-hybrid system.
METHODS: We constructed F protein bait plasmid by cloning the gene of F protein into pGBKT7, then recombinant plasmid DNA was transformed into yeast AH109 (a type). The transformed yeast AH109 was mated with yeast Y187 (α type) containing liver cDNA library plasmid in 2×YPDA medium. Diploid yeast was plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing X-α-gal for selection and screening. After extracting and sequencing plasmids from positive (blue) colonies, we underwent sequence analysis by bioinformatics.
RESULTS: Thirty-six colonies were selected and sequenced. Among them, 11 colonies were zymogen granule protein, 5 colonies were zinc finger protein, 4 colonies were zinc-α-2-glycoprotein, 1 colony was sialyltransferase, 1 colony was complement control protein factor I, 1 colony was vitronectin, and 2 colonies were new genes with unknown function.
CONCLUSION: The yeast two-hybrid system is an effective method for identifying hepatocyte proteins interacting with F protein of hepatitis C virus. F protein may bind to different proteins.
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Affiliation(s)
- Yan-Ping Huang
- Department of Pediatrics, the First Hospital of Xi'an Jiaotong University, Shaanxi Province, China.
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Pickett JA, Thorn P, Edwardson JM. The Plasma Membrane Q-SNARE Syntaxin 2 Enters the Zymogen Granule Membrane during Exocytosis in the Pancreatic Acinar Cell. J Biol Chem 2005; 280:1506-11. [PMID: 15536072 DOI: 10.1074/jbc.m411967200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During exocytosis in the pancreatic acinar cell, zymogen granules fuse directly with the apical plasma membrane and also with granules that have themselves fused with the plasma membrane. Together, these primary and secondary fusion events constitute the process of compound exocytosis. It has been suggested that the sequential nature of primary and secondary fusion is a consequence of the requirement for plasma membrane soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptors, such as syntaxin 2, to enter the membrane of the primary fused granule. We have tested this possibility by determining the location of syntaxin 2 in unstimulated and stimulated pancreatic acini. Syntaxin 2 was imaged by confocal immunofluorescence microscopy. Fused granules were detected both through their filling with the aqueous dye lysine-fixable Texas Red-dextran and through the decoration of their cytoplasmic surfaces with filamentous actin. In unstimulated cells, syntaxin 2 was exclusively present on the apical plasma membrane. In contrast, after stimulation, syntaxin 2 had moved into the membranes of fused granules, as judged by its location around dye-filled structures of 1-mum diameter that were coated with filamentous actin. At long times of stimulation (5 min), the majority (85%) of dye-filled granules were also positive for syntaxin 2. In contrast, at shorter times (1 min), more dye-filled granules (29%) were syntaxin 2-negative. We conclude that syntaxin 2 enters the membrane of a fused zymogen granule after the opening of the fusion pore, and we suggest that this movement might permit the onset of secondary fusion.
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Affiliation(s)
- James A Pickett
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
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35
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Schuck S, Simons K. Polarized sorting in epithelial cells: raft clustering and the biogenesis of the apical membrane. J Cell Sci 2004; 117:5955-64. [PMID: 15564373 DOI: 10.1242/jcs.01596] [Citation(s) in RCA: 241] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Polarized cells establish and maintain functionally distinct surface domains by an elaborate sorting process, which ensures accurate delivery of biosynthetic cargo to different parts of the plasma membrane. This is particularly evident in polarized epithelial cells, which have been used as a model system for studies of sorting mechanisms. The clustering of lipid rafts through the oligomerization of raft components could be utilized for segregating apical from basolateral cargo and for the generation of intracellular transport carriers. Besides functioning in polarized sorting in differentiated cells, raft clustering might also play an important role in the biogenesis of apical membrane domains during development.
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Affiliation(s)
- Sebastian Schuck
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
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36
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Hinz B, Ramer R, Eichele K, Weinzierl U, Brune K. R(+)-methanandamide-induced cyclooxygenase-2 expression in H4 human neuroglioma cells: possible involvement of membrane lipid rafts. Biochem Biophys Res Commun 2004; 324:621-6. [PMID: 15474472 DOI: 10.1016/j.bbrc.2004.09.095] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Indexed: 11/20/2022]
Abstract
Cannabinoids induce the expression of the cyclooxygenase-2 (COX-2) isoenzyme in H4 human neuroglioma cells via a pathway independent of cannabinoid- or vanilloid receptor activation. The underlying mechanism was recently shown to involve increased synthesis of ceramide, which in turn leads to activation of p38 and p42/44 mitogen-activated protein kinases (MAPKs). The present study investigates a possible contribution of membrane lipid rafts to cannabinoid-induced COX-2 expression. To address this issue, we tested the influence of methyl-beta-cyclodextrin (MCD), a membrane cholesterol depletor, on COX-2 expression by the endocannabinoid analogue R(+)-methanandamide (R(+)-MA). Incubation of H4 cells with MCD was associated with a loss of lipid raft integrity and a substantial inhibition of R(+)-MA-induced COX-2 expression and subsequent formation of prostaglandin E2. Moreover, MCD was shown to suppress signal transduction steps upstream to COX-2 induction by R(+)-MA. Accordingly, the cholesterol depletor suppressed R(+)-MA-induced formation of ceramide as well as phosphorylation of p38 and p42/44 MAPKs. Together, our results suggest that R(+)-MA induces COX-2 expression in human neuroglioma cells via a pathway linked to lipid raft microdomains.
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Affiliation(s)
- Burkhard Hinz
- Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich Alexander University Erlangen-Nürnberg, Fahrstrasse 17, D-91054 Erlangen, Germany.
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37
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Yu S, Michie SA, Lowe AW. Absence of the Major Zymogen Granule Membrane Protein, GP2, Does Not Affect Pancreatic Morphology or Secretion. J Biol Chem 2004; 279:50274-9. [PMID: 15385539 DOI: 10.1074/jbc.m410599200] [Citation(s) in RCA: 38] [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
The majority of digestive enzymes in humans are produced in the pancreas where they are stored in zymogen granules before secretion into the intestine. GP2 is the major membrane protein present in zymogen granules of the exocrine pancreas. Numerous studies have shown that GP2 binds digestive enzymes such as amylase, thereby supporting a role in protein sorting to the zymogen granule. Other studies have suggested that GP2 is important in the formation of zymogen granules. A knock-out mouse was generated for GP2 to study the impact of the protein on pancreatic function. GP2-deficient mice displayed no gross signs of nutrient malab-sorption such as weight loss, growth retardation, or diarrhea. Zymogen granules in the GP2 knock-out mice appeared normal on electron microscopy and contained the normal complement of proteins excluding GP2. Primary cultures of pancreatic acini appropriately responded to secretagogue stimulation with the secretion of digestive enzymes. The course of experimentally induced pancreatitis was also examined in the knock-out mice because proteins known to associate with GP2 have been found to possess a protective role. When GP2 knock-out mice were subjected to two different models of pancreatitis, no major differences were detected. In conclusion, GP2 is not essential for pancreatic exocrine secretion or zymogen granule formation. It is unlikely that GP2 serves a major intracellular role within the pancreatic acinar cell and may be functionally active after it is secreted from the pancreas.
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Affiliation(s)
- Su Yu
- Department of Medicine, Satnford University, Stanford, CA 94305, USA
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38
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Laughlin RC, McGugan GC, Powell RR, Welter BH, Temesvari LA. Involvement of raft-like plasma membrane domains of Entamoeba histolytica in pinocytosis and adhesion. Infect Immun 2004; 72:5349-57. [PMID: 15322032 PMCID: PMC517461 DOI: 10.1128/iai.72.9.5349-5357.2004] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Accepted: 05/22/2004] [Indexed: 01/11/2023] Open
Abstract
Lipid rafts are highly ordered, cholesterol-rich, and detergent-resistant microdomains found in the plasma membrane of many eukaryotic cells. These domains play important roles in endocytosis, secretion, and adhesion in a variety of cell types. The parasitic protozoan Entamoeba histolytica, the causative agent of amoebic dysentery, was determined to have raft-like plasma membrane domains by use of fluorescent lipid analogs that specifically partition into raft and nonraft regions of the membrane. Disruption of raft-like membrane domains in Entamoeba with the cholesterol-binding agents filipin and methyl-beta-cyclodextrin resulted in the inhibition of several important virulence functions, fluid-phase pinocytosis, and adhesion to host cell monolayers. However, disruption of raft-like domains did not inhibit constitutive secretion of cysteine proteases, another important virulence function of Entamoeba. Flotation of the cold Triton X-100-insoluble portion of membranes on sucrose gradients revealed that the heavy, intermediate, and light subunits of the galactose-N-acetylgalactosamine-inhibitible lectin, an important cell surface adhesion molecule of Entamoeba, were enriched in cholesterol-rich (raft-like) fractions, whereas EhCP5, another cell surface molecule, was not enriched in these fractions. The subunits of the lectin were also observed in high-density, actin-rich fractions of the sucrose gradient. Together, these data suggest that pinocytosis and adhesion are raft-dependent functions in this pathogen. This is the first report describing the existence and physiological relevance of raft-like membrane domains in E. histolytica.
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Affiliation(s)
- Richard C Laughlin
- Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC 29634, USA
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39
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Yu S, Hao Y, Lowe AW. Effects of GP2 expression on secretion and endocytosis in pancreatic AR4-2J cells. Biochem Biophys Res Commun 2004; 322:320-5. [PMID: 15313209 DOI: 10.1016/j.bbrc.2004.07.120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Indexed: 10/26/2022]
Abstract
GP2 is the major membrane protein present in secretory granules of the exocrine pancreas. GP2's function is unknown, but a role in digestive enzyme packaging or secretion from secretory granules has been proposed. In addition, GP2 has been proposed to influence endocytosis and membrane recycling following stimulated secretion. Adenovirus-mediated GP2 overexpression in the rat pancreatic cell line AR4-2J was used to study its impact on digestive enzyme secretion and membrane recycling. Immunoelectron microscopy showed that GP2 and amylase co-localized in secretory granules in infected AR4-2J cells. CCK-8 stimulation resulted in a fourfold increase in amylase secretion with or without GP2 expression. GP2 expression also did not influence endocytosis following CCK-8 stimulation. Thus, GP2 expression in AR4-2J cells does not affect amylase packaging in secretory granules or stimulated secretion. GP2 expression also does not influence membrane recycling in response to stimulated stimulation in AR4-2J cells.
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Affiliation(s)
- Su Yu
- Department of Medicine and the Digestive Disease Center, Stanford University, Stanford, CA, USA
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40
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N/A. N/A. Shijie Huaren Xiaohua Zazhi 2004; 12:1701-1704. [DOI: 10.11569/wcjd.v12.i7.1701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
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41
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Neuschwander-Tetri BA, Fimmel CJ, Kladney RD, Wells LD, Talkad V. Differential expression of the trypsin inhibitor SPINK3 mRNA and the mouse ortholog of secretory granule protein ZG-16p mRNA in the mouse pancreas after repetitive injury. Pancreas 2004; 28:e104-11. [PMID: 15097871 DOI: 10.1097/00006676-200405000-00022] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A mouse model using repetitive acinar cell injury caused by supraphysiologic doses of cerulein to induce the characteristic fibrosis and loss of acinar cell mass found in human chronic pancreatitis was employed to identify early changes in gene expression. A gene array was used to detect changes in 18,000 expressed sequence tags; changes in specific transcripts were confirmed by RNase protection assays. These methods identified SPINK3, the mouse homologue of human and rat protease inhibitor genes, as being highly expressed in the pancreas and induced after pancreatic injury. Because SPINK3 may be an important serine protease inhibitor, its up-regulation may reflect an important endogenous cytoprotective mechanism in preventing further injury. The up-regulation of SPINK3 was specific; the mouse homologue of the zymogen-processing protein ZG-16p was also highly expressed in the pancreas but sharply down-regulated early in the course of injury. These findings suggest that the pancreatic acinar cell may respond to injury with a program of self-preservation and loss of normal function.
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42
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Thorn P, Fogarty KE, Parker I. Zymogen granule exocytosis is characterized by long fusion pore openings and preservation of vesicle lipid identity. Proc Natl Acad Sci U S A 2004; 101:6774-9. [PMID: 15090649 PMCID: PMC404121 DOI: 10.1073/pnas.0400336101] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The dynamics of the fusion pore that forms between a secretory vesicle and the plasma membrane are important in the regulation of both exocytosis and endocytosis. Here, we describe characteristics of fusion during zymogen granule exocytosis in exocrine pancreatic acinar cells. By using fluorescence recovery after photobleaching techniques, we show that the fusion pore remains open to allow free aqueous exchange with the vesicle lumen. There is no lipid interchange between the plasma and granule membranes during this time, and at the end of its life, the intact granule shrinks in situ, probably by a gradual pinching off of membrane patches. We propose that the protracted fusion pore lifetime is adapted to permit compound exocytosis, whereby the lingering primary granule acts as a conduit through which the contents of a secondary granule can be released. The lack of lipid intermixing may then facilitate selective recycling of granule membrane and preservation of apical membrane integrity.
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Affiliation(s)
- Peter Thorn
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom.
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43
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Burgos PV, Klattenhoff C, de la Fuente E, Rigotti A, González A. Cholesterol depletion induces PKA-mediated basolateral-to-apical transcytosis of the scavenger receptor class B type I in MDCK cells. Proc Natl Acad Sci U S A 2004; 101:3845-50. [PMID: 15007173 PMCID: PMC374332 DOI: 10.1073/pnas.0400295101] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cholesterol-based membrane microdomains, or lipid rafts, are believed to play important, yet poorly defined, roles in protein trafficking and signal transduction. In polarized epithelial cells, the current view is that rafts are involved in apical but not in basolateral protein transport from the trans-Golgi network (TGN). We report here that cholesterol is required in a post-TGN mechanism of basolateral regionalization. Permanently transfected Madin-Darby canine kidney cells segregated the caveolae/raft-associated high-density lipoprotein scavenger receptor class B type I (SR-BI) predominantly to the basolateral domain where it was constitutively internalized and recycled basolaterally. Acute cholesterol depletion did not significantly alter SR-BI internalization, implying a cholesterol depletion-insensitive endocytic process but instead induced its transcytosis through a protein kinase A (PKA)- and microtubule-dependent mechanism. Forskolin also elicited SR-BI transcytosis. The basolateral distribution of endogenous epidermal growth factor receptor remained unaffected. Strikingly, cholesterol depletion induced PKA activity without increasing the cAMP levels. Thus, our results are consistent with a scenario in which cholesterol-based rafts promote internalization and basolateral recycling of internalized SR-BI whereas a PKA pool sensitive to cholesterol depletion mediates SR-BI transcytosis. Regulated transcytosis of SR-BI may provide an additional mechanism to control cholesterol homeostasis. These results disclose relationships between cholesterol-based rafts and PKA activity operating in a post-TGN mechanism of regulated apical-to-basolateral cell surface protein distribution.
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Affiliation(s)
- Patricia V Burgos
- Centro de Regulación Celular y Patología, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica, Santiago 6510260, Chile
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44
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Wadehra M, Goodglick L, Braun J. The tetraspan protein EMP2 modulates the surface expression of caveolins and glycosylphosphatidyl inositol-linked proteins. Mol Biol Cell 2004; 15:2073-83. [PMID: 14978215 PMCID: PMC404005 DOI: 10.1091/mbc.e03-07-0488] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Caveolae are a subset of lipid rafts enriched in glycosphingolipids and cholesterol-rich domains, but selectively lacking glycosylphosphatidyl inositol-anchored proteins (GPI-APs). Caveolin proteins are the organizing component of caveolae, but the corresponding proteins for other classes of lipid rafts are poorly defined. Epithelial membrane protein-2 (EMP2), a member of the four-transmembrane superfamily, facilitates plasma membrane delivery of certain integrins. In this study, we found by laser confocal microscopy that EMP2 was associated with GPI-APs (detected by the GPI-AP binding bacterial toxin proaerolysin). Biochemical membrane fractionation and methyl-beta-cyclodextrin treatment demonstrated that this association occurred within lipid rafts. EMP2 did not associate with caveolin-bearing membrane structures, and recombinant overexpression of EMP2 in NIH3T3 cells decreased caveolin-1 and caveolin-2 protein levels while increasing the surface expression of GPI-APs. Conversely, a ribozyme construct that specifically cleaves the EMP2 transcript reduced surface GPI-APs and increased caveolin protein expression. These findings suggest that EMP2 facilitates the formation and surface trafficking of lipid rafts bearing GPI-APs, and reduces caveolin expression, resulting in impaired formation of caveolae.
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Affiliation(s)
- Madhuri Wadehra
- Molecular Biology Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA
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45
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Abstract
There has been considerable recent interest in the possibility that the plasma membrane contains lipid "rafts," microdomains enriched in cholesterol and sphingolipids. It has been suggested that such rafts could play an important role in many cellular processes including signal transduction, membrane trafficking, cytoskeletal organization, and pathogen entry. However, rafts have proven difficult to visualize in living cells. Most of the evidence for their existence and function relies on indirect methods such as detergent extraction, and a number of recent studies have revealed possible problems with these methods. Direct studies of the distribution of raft components in living cells have not yet reached a consensus on the size or even the presence of these microdomains, and hence it seems that a definitive proof of raft existence has yet to be obtained.
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Affiliation(s)
- Sean Munro
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, United Kingdom.
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46
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Lisman Q, Pomorski T, Vogelzangs C, Urli-Stam D, de Cocq van Delwijnen W, Holthuis JCM. Protein sorting in the late Golgi of Saccharomyces cerevisiae does not require mannosylated sphingolipids. J Biol Chem 2003; 279:1020-9. [PMID: 14583628 DOI: 10.1074/jbc.m306119200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Glycosphingolipids are widely viewed as integral components of the Golgi-based machinery by which membrane proteins are targeted to compartments of the endosomal/lysosomal system and to the surface domains of polarized cells. The yeast Saccharomyces cerevisiae creates glycosphingolipids by transferring mannose to the head group of inositol phosphorylceramide (IPC), yielding mannosyl-IPC (MIPC). Addition of an extra phosphoinositol group onto MIPC generates mannosyldi-IPC (M(IP)2C), the final and most abundant sphingolipid in yeast. Mannosylation of IPC is partially dependent on CSG1, a gene encoding a putative sphingolipidmannosyltransferase. Here we show that open reading frame YBR161w, renamed CSH1, is functionally homologous to CSG1 and that deletion of both genes abolishes MIPC and M(IP)2C synthesis without affecting protein mannosylation. Csg1p and Csh1p are closely related polytopic membrane proteins that co-localize with IPC synthase in the medial-Golgi. Loss of Csg1p and Csh1p has no effect on clathrin- or AP-3 adaptor-mediated protein transport from the Golgi to the vacuole. Moreover, segregation of the periplasmic enzyme invertase, the plasma membrane ATPase Pma1p and the glycosylphosphatidylinositol-anchored protein Gas1p into distinct classes of secretory vesicles occurs independently of Csg1p and Csh1p. Our results indicate that protein sorting in the late Golgi of yeast does not require production of mannosylated sphingolipids.
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Affiliation(s)
- Quirine Lisman
- Department of Membrane Enzymology, Utrecht University Faculty of Chemistry, 3584 CH Utrecht, The Netherlands
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47
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Pombo I, Rivera J, Blank U. Munc18-2/syntaxin3 complexes are spatially separated from syntaxin3-containing SNARE complexes. FEBS Lett 2003; 550:144-8. [PMID: 12935901 DOI: 10.1016/s0014-5793(03)00864-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Exocytosis of mast cell granules requires a vesicular- and plasma membrane-associated fusion machinery. We examined the distribution of SNARE membrane fusion and Munc18 accessory proteins in lipid rafts of RBL mast cells. SNAREs were found either excluded (syntaxin2), equally distributed between raft and non-raft fractions (syntaxin4, VAMP-8, VAMP-2), or selectively enriched in rafts (syntaxin3, SNAP-23). Syntaxin4-binding Munc18-3 was absent, whereas small amounts of the syntaxin3-interacting partner Munc18-2 consistently distributed into rafts. Cognate SNARE complexes of syntaxin3 with SNAP-23 and VAMP-8 were enriched in rafts, whereas Munc18-2/syntaxin3 complexes were excluded. This demonstrates a spatial separation between these two types of complexes and suggests that Munc18-2 acts in a step different from SNARE complex formation and fusion.
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Affiliation(s)
- Isabel Pombo
- Unité d'Immuno-Allergie, Institut Pasteur, Paris, France
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Herr C, Clemen CS, Lehnert G, Kutschkow R, Picker SM, Gathof BS, Zamparelli C, Schleicher M, Noegel AA. Function, expression and localization of annexin A7 in platelets and red blood cells: insights derived from an annexin A7 mutant mouse. BMC BIOCHEMISTRY 2003; 4:8. [PMID: 12925238 PMCID: PMC194730 DOI: 10.1186/1471-2091-4-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2003] [Accepted: 08/19/2003] [Indexed: 11/13/2022]
Abstract
BACKGROUND Annexin A7 is a Ca2+- and phospholipid-binding protein expressed as a 47 and 51 kDa isoform, which is thought to be involved in membrane fusion processes. Recently the 47 kDa isoform has been identified in erythrocytes where it was proposed to be a key component in the process of the Ca2+-dependent vesicle release, a process with which red blood cells might protect themselves against an attack by for example complement components. RESULTS The role of annexin A7 in red blood cells was addressed in erythrocytes from anxA7-/- mice. Interestingly, the Ca2+-mediated vesiculation process was not impaired. Also, the membrane organization appeared not to be disturbed as assessed using gradient fractionation studies. Instead, lack of annexin A7 led to an altered cell shape and increased osmotic resistance of red blood cells. Annexin A7 was also identified in platelets. In these cells its loss led to a slightly slower aggregation velocity which seems to be compensated by an increased number of platelets. The results appear to rule out an important role of annexin A7 in membrane fusion processes occurring in red blood cells. Instead the protein might be involved in the organization of the membrane cytoskeleton. Red blood cells may represent an appropriate model to study the role of annexin A7 in cellular processes. CONCLUSION We have demonstrated the presence of both annexin A7 isoforms in red blood cells and the presence of the small isoform in platelets. In both cell types the loss of annexin A7 impairs cellular functions. The defects observed are however not compatible with a crucial role for annexin A7 in membrane fusion processes in these cell types.
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Affiliation(s)
- Claudia Herr
- Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany
| | - Christoph S Clemen
- Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany
| | - Gisela Lehnert
- Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany
| | - Rüdiger Kutschkow
- Institute for Clinical Chemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 9, 50924 Cologne, Germany
| | - Susanne M Picker
- Transfusion Medicine, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 9, 50924 Cologne, Germany
| | - Birgit S Gathof
- Transfusion Medicine, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 9, 50924 Cologne, Germany
| | - Carlotta Zamparelli
- Centro Biologia Molecolare CNR, Dipartimento di Scienze Biochimiche, Universita La Sapienza, P.le A. Moro, 5, 00185 Roma, Italy
| | - Michael Schleicher
- Institut für Zellbiologie, Ludwig-Maximilians-Universität München, Germany
| | - Angelika A Noegel
- Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, Germany
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Meacham CA, Johnson AD. An embryonic chick pancreas organ culture model: characterization and neural control of exocrine release. Auton Neurosci 2003; 105:118-30. [PMID: 12798208 DOI: 10.1016/s1566-0702(03)00046-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
An embryonic chick (Gallus domesticus) whole-organ pancreas culture system was developed for use as an in vitro model to study cholinergic regulation of exocrine pancreatic function. The culture system was examined for characteristic exocrine function and viability by measuring enzyme release, and noting histological, morphological, and anti-amylase immuno-fluorescence staining changes over a series of incubation times. This embryonic culture system exhibits loss of viability and morphological degeneration after 12 h of incubation time. Characterization and development of this exocrine model system was an important aspect of this study. Assessment of the 18-day-old embryonic chick pancreas model clearly indicated biochemical and cholinergic functionality, and morphological integrity, of the tissue after 4-h incubation. This embryonic age and incubation period were utilized for all subsequent cholinergic studies. The in vitro model was used to study parasympathetic regulation of exocrine function via the muscarinc receptors present in the embryonic chick pancreas. The effects of synthetic muscarinic agonists (bethanechol and carbachol) and subtype-specific antagonists affected amylase release to varying degrees suggesting heterogeneity of receptors. The effects of the muscarinic receptor antagonists atropine (non-specific), pirenzepine (M(1)-selective) and 4-DAMP [4-diphenylacetoxy-N-methyl-piperidine methiodide] (M(3)-selective) on bethanechol-stimulated amylase release were examined. Atropine and 4-DAMP at concentrations of 2 microM and higher significantly inhibited (p<0.05) agonist-stimulated amylase release, while pirenzipine did not at 2 microM, but did at 200 microM. The M(3) subtype selective antagonist 4-DAMP (2 pM-2 mM) significantly inhibited (p<0.05) 5 mM bethanechol-stimulated amylase release at concentrations of 2 microM and greater (amylase activity decreased from 100.61 to 49.41 U/l/mg). The data suggest the existence of a muscarinic receptor subtype for the embryonic chick pancreas exocrine cells characteristic to the mammalian M(3) glandular subtype.
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Affiliation(s)
- Connie A Meacham
- U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Neurotoxicology Division, Neurophysiology Branch, MD B105-05, Research Triangle Park, NC 27711, USA
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Thomas DDH, Kaspar KM, Taft WB, Weng N, Rodenkirch LA, Groblewski GE. Identification of annexin VI as a Ca2+-sensitive CRHSP-28-binding protein in pancreatic acinar cells. J Biol Chem 2002; 277:35496-502. [PMID: 12105190 DOI: 10.1074/jbc.m110917200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CRHSP-28 is a member of the tumor protein D52 protein family that was recently shown to regulate Ca(2+)-stimulated secretory activity in streptolysin-O-permeabilized acinar cells (Thomas, D. H., Taft, W. B., Kaspar, K. M., and Groblewski, G. E. (2001) J. Biol. Chem. 276, 28866-28872). In the present study, the Ca(2+)-sensitive phospholipid-binding protein annexin VI was purified from rat pancreas as a CRHSP-28-binding protein. The interaction between CRHSP-28 and annexin VI was demonstrated by coimmunoprecipitation and gel-overlay assays and was shown to require low micromolar levels of free Ca(2+), indicating these molecules likely interact under physiological conditions. Immunofluorescence microscopy confirmed a dual localization of CRHSP-28 and annexin VI, which appeared in a punctate pattern in the supranuclear and apical cytoplasm of acini. Stimulation of cells for 5 min with the secretagogue cholecystokinin enhanced the colocalization of CRHSP-28 and annexin VI within regions of acini immediately below the apical plasma membrane. Tissue fractionation revealed that CRHSP-28 is a peripheral membrane protein that is highly enriched in smooth microsomal fractions of pancreas. Further, the content of CRHSP-28 in microsomes was significantly reduced in pancreatic tissue obtained from rats that had been infused with a secretory dose of cholecystokinin for 40 min, demonstrating that secretagogue stimulation transiently alters the association of CRHSP-28 with membranes in cells. Collectively, the Ca(2+)-dependent binding of CRHSP-28 and annexin VI, together with their colocalization in the apical cytoplasm, is consistent with a role for these molecules in acinar cell membrane trafficking events that are essential for digestive enzyme secretion.
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Affiliation(s)
- Diana D H Thomas
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA
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