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O'Neill RS, Stoita A. Biomarkers in the diagnosis of pancreatic cancer: Are we closer to finding the golden ticket? World J Gastroenterol 2021; 27:4045-4087. [PMID: 34326612 PMCID: PMC8311531 DOI: 10.3748/wjg.v27.i26.4045] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/24/2021] [Accepted: 06/15/2021] [Indexed: 02/06/2023] Open
Abstract
Pancreatic cancer (PC) is a leading cause of cancer related mortality on a global scale. The disease itself is associated with a dismal prognosis, partly due to its silent nature resulting in patients presenting with advanced disease at the time of diagnosis. To combat this, there has been an explosion in the last decade of potential candidate biomarkers in the research setting in the hope that a diagnostic biomarker may provide a glimmer of hope in what is otherwise quite a substantial clinical dilemma. Currently, serum carbohydrate antigen 19-9 is utilized in the diagnostic work-up of patients diagnosed with PC however this biomarker lacks the sensitivity and specificity associated with a gold-standard marker. In the search for a biomarker that is both sensitive and specific for the diagnosis of PC, there has been a paradigm shift towards a focus on liquid biopsy and the use of diagnostic panels which has subsequently proved to have efficacy in the diagnosis of PC. Currently, promising developments in the field of early detection on PC using diagnostic biomarkers include the detection of microRNA (miRNA) in serum and circulating tumour cells. Both these modalities, although in their infancy and yet to be widely accepted into routine clinical practice, possess merit in the early detection of PC. We reviewed over 300 biomarkers with the aim to provide an in-depth summary of the current state-of-play regarding diagnostic biomarkers in PC (serum, urinary, salivary, faecal, pancreatic juice and biliary fluid).
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Affiliation(s)
- Robert S O'Neill
- Department of Gastroenterology, St Vincent's Hospital Sydney, Sydney 2010, Australia
- St George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney 2010, Australia
| | - Alina Stoita
- Department of Gastroenterology, St Vincent's Hospital Sydney, Sydney 2010, Australia
- St Vincent’s Clinical School, Faculty of Medicine, University of New South Wales, Sydney 2010, Australia
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2
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Nagabhyru P, Dinkins RD, Schardl CL. Transcriptomics of Epichloë-Grass Symbioses in Host Vegetative and Reproductive Stages. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:194-207. [PMID: 30145935 DOI: 10.1094/mpmi-10-17-0251-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Epichloë species are fungal symbionts (endophytes) of cool-season grasses that transmit vertically via inflorescence primordia (IP), ovaries (OV), and ultimately, embryos. Epichloë coenophiala, an endophyte of tall fescue (Schedonorus arundinaceus), provides multiple protective benefits to the grass. We conducted transcriptome analysis of the tall fescue-E. coenophiala symbiosis, comparing IP, OV, vegetative pseudostems (PS), and the lemma and palea (LP) (bracts) of the young floret. Transcriptomes of host OV and PS exhibited almost no significant differences attributable to endophyte presence or absence. Comparison of endophyte gene expression in different plant parts revealed numerous differentially expressed genes (DEGs). The 150 endophyte DEGs significantly higher in PS over OV included genes for alkaloid biosynthesis and sugar or amino acid transport. The 277 endophyte DEGs significantly higher in OV over PS included genes for protein chaperones (including most heat-shock proteins), trehalose synthesis complex, a bax inhibitor-1 protein homolog, the CLC chloride ion channel, catalase, and superoxide dismutase. Similar trends were apparent in the Brachypodium sylvaticum-Epichloë sylvatica symbiosis. Gene expression profiles in tall fescue IP and LP indicated that the endophyte transcriptome shift began early in host floral development. We discuss possible roles of the endophyte DEGs in colonization of reproductive grass tissues.
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Affiliation(s)
- Padmaja Nagabhyru
- 1 Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, U.S.A.; and
| | - Randy D Dinkins
- 2 USDA-ARS, Forage-Animal Production Research Unit, Lexington, KY 40546, U.S.A
| | - Christopher L Schardl
- 1 Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, U.S.A.; and
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3
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Boggs K, Wang T, Orabi AI, Mukherjee A, Eisses JF, Sun T, Wen L, Javed TA, Esni F, Chen W, Husain SZ. Pancreatic gene expression during recovery after pancreatitis reveals unique transcriptome profiles. Sci Rep 2018; 8:1406. [PMID: 29362419 PMCID: PMC5780441 DOI: 10.1038/s41598-018-19392-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 12/29/2017] [Indexed: 02/07/2023] Open
Abstract
It is well known that pancreatic recovery after a single episode of injury such as an isolated bout of pancreatitis occurs rapidly. It is unclear, however, what changes are inflicted in such conditions to the molecular landscape of the pancreas. In the caerulein hyperstimulation model of pancreatitis, the murine pancreas has the ability to recover within one week based on histological appearance. In this study, we sought to characterize by RNA-sequencing (RNA-seq) the transcriptional profile of the recovering pancreas up to two weeks post-injury. We found that one week after injury there were 319 differentially expressed genes (DEGs) compared with baseline and that after two weeks there were 53 DEGs. Forty (12.5%) of the DEGs persisted from week one to week two, and another 13 DEGs newly emerged in the second week. Amongst the top up-regulated DEGs were several trypsinogen genes (trypsinogen 4, 5, 12, 15, and 16). To our knowledge, this is the first characterization of the transcriptome during pancreatic recovery by deep sequencing, and it reveals on a molecular basis that there is an ongoing recovery of the pancreas even after apparent histological resolution. The findings also raise the possibility of an emerging novel transcriptome upon pancreatic recovery.
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Affiliation(s)
- Kristy Boggs
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15224, USA
| | - Ting Wang
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15224, USA
- Department of Biostatistics, School of Public Health, University of Pittsburgh, Pittsburgh, PA, 15224, USA
| | - Abrahim I Orabi
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15224, USA
| | - Amitava Mukherjee
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15224, USA
| | - John F Eisses
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15224, USA
| | - Tao Sun
- Department of Biostatistics, School of Public Health, University of Pittsburgh, Pittsburgh, PA, 15224, USA
| | - Li Wen
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15224, USA
| | - Tanveer A Javed
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15224, USA
| | - Farzad Esni
- Department of Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15224, USA
| | - Wei Chen
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15224, USA
- Department of Biostatistics, School of Public Health, University of Pittsburgh, Pittsburgh, PA, 15224, USA
| | - Sohail Z Husain
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15224, USA.
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Oxidative stress and NO generation in the rat pancreatitis induced by pancreatic duct ligation. Acta Histochem 2017; 119:252-256. [PMID: 28168994 DOI: 10.1016/j.acthis.2017.01.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/23/2017] [Accepted: 01/27/2017] [Indexed: 12/28/2022]
Abstract
The interaction between nitric oxide (NO) and superoxides is critical in the development of an acute pancreatitis. Previously, we reported that the expression of superoxides and of the NO-generating enzyme (NO synthase, NOS) was up-regulated in the human pancreatitis, especially within the exocrine compartment indicating an exceptional susceptibility of the exocrine parenchyma to oxidative stress. The aim of the present study was to compare the regulation of NO signalling pathways in the human pancreatitis and in an animal model of an acute pancreatitis induced by pancreatic duct ligation (PDL) in rats. In the PDL-induced rat pancreatitis, we revealed a similar pattern of oxidative stress and NOS up-regulation in acinar and in ductal compartments, like in the human pancreatitis. This demonstrates that the PDL-induced rat pancreatitis is a proper model for further studies of acute pancreatitis development in humans.
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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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Buchwalow I, Schnekenburger J, Tiemann K, Samoilova V, Bankfalvi A, Poremba C, Schleicher C, Neumann J, Boecker W. L-arginine-NO-cGMP signalling pathway in pancreatitis. Sci Rep 2013; 3:1899. [PMID: 23712581 PMCID: PMC3664897 DOI: 10.1038/srep01899] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 05/10/2013] [Indexed: 01/25/2023] Open
Abstract
The role of nitric oxide (NO) in the human pancreas and in pancreatitis still remains controversial. Furthermore, conflicting conclusions have been reached by different laboratories about the localization of the NO-generating enzyme (NO synthase, NOS) in the pancreas. Here, we investigated the co-expression of NOS with enzymes involved in regulation of NO signalling in the normal human pancreas and in pancreatitis. We found that the whole NO signalling machinery was up-regulated in pancreatitis, especially within the exocrine compartment. Furthermore, the exocrine parenchymal cells revealed higher levels of oxidative stress markers, nitrotyrosine and 8-hydroxyguanosine, in pancreatitis, which reflects the exceptional susceptibility of the exocrine parenchyma to oxidative stress. This study provides a direct link between oxidative stress and the enzymatic control of the NO bioavailability at the cellular level and endows with further insight into fundamental mechanisms underlying pancreatic disorders associated with disruptions in the L-arginine-NO-cGMP signalling enzyme cascade.
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Makawita S, Dimitromanolakis A, Soosaipillai A, Soleas I, Chan A, Gallinger S, Haun RS, Blasutig IM, Diamandis EP. Validation of four candidate pancreatic cancer serological biomarkers that improve the performance of CA19.9. BMC Cancer 2013; 13:404. [PMID: 24007603 PMCID: PMC3847832 DOI: 10.1186/1471-2407-13-404] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 08/29/2013] [Indexed: 12/11/2022] Open
Abstract
Background The identification of new serum biomarkers with high sensitivity and specificity is an important priority in pancreatic cancer research. Through an extensive proteomics analysis of pancreatic cancer cell lines and pancreatic juice, we previously generated a list of candidate pancreatic cancer biomarkers. The present study details further validation of four of our previously identified candidates: regenerating islet-derived 1 beta (REG1B), syncollin (SYCN), anterior gradient homolog 2 protein (AGR2), and lysyl oxidase-like 2 (LOXL2). Methods The candidate biomarkers were validated using enzyme-linked immunosorbent assays in two sample sets of serum/plasma comprising a total of 432 samples (Sample Set A: pancreatic ductal adenocarcinoma (PDAC, n = 100), healthy (n = 92); Sample Set B: PDAC (n = 82), benign (n = 41), disease-free (n = 47), other cancers (n = 70)). Biomarker performance in distinguishing PDAC from each control group was assessed individually in the two sample sets. Subsequently, multiparametric modeling was applied to assess the ability of all possible two and three marker panels in distinguishing PDAC from disease-free controls. The models were generated using sample set B, and then validated in Sample Set A. Results Individually, all markers were significantly elevated in PDAC compared to healthy controls in at least one sample set (p ≤ 0.01). SYCN, REG1B and AGR2 were also significantly elevated in PDAC compared to benign controls (p ≤ 0.01), and AGR2 was significantly elevated in PDAC compared to other cancers (p < 0.01). CA19.9 was also assessed. Individually, CA19.9 showed the greatest area under the curve (AUC) in receiver operating characteristic (ROC) analysis when compared to the tested candidates; however when analyzed in combination, three panels (CA19.9 + REG1B (AUC of 0.88), CA19.9 + SYCN + REG1B (AUC of 0.87) and CA19.9 + AGR2 + REG1B (AUC of 0.87)) showed an AUC that was significantly greater (p < 0.05) than that of CA19.9 alone (AUC of 0.82). In a comparison of early-stage (Stage I-II) PDAC to disease free controls, the combination of SYCN + REG1B + CA19.9 showed the greatest AUC in both sample sets, (AUC of 0.87 and 0.92 in Sets A and B, respectively). Conclusions Additional serum biomarkers, particularly SYCN and REG1B, when combined with CA19.9, show promise as improved diagnostic indicators of pancreatic cancer, which therefore warrants further validation.
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Affiliation(s)
- Shalini Makawita
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
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Makawita S, Smith C, Batruch I, Zheng Y, Rückert F, Grützmann R, Pilarsky C, Gallinger S, Diamandis EP. Integrated proteomic profiling of cell line conditioned media and pancreatic juice for the identification of pancreatic cancer biomarkers. Mol Cell Proteomics 2011; 10:M111.008599. [PMID: 21653254 PMCID: PMC3205865 DOI: 10.1074/mcp.m111.008599] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Revised: 05/19/2011] [Indexed: 12/13/2022] Open
Abstract
Pancreatic cancer is one of the leading causes of cancer-related deaths, for which serological biomarkers are urgently needed. Most discovery-phase studies focus on the use of one biological source for analysis. The present study details the combined mining of pancreatic cancer-related cell line conditioned media and pancreatic juice for identification of putative diagnostic leads. Using strong cation exchange chromatography, followed by LC-MS/MS on an LTQ-Orbitrap mass spectrometer, we extensively characterized the proteomes of conditioned media from six pancreatic cancer cell lines (BxPc3, MIA-PaCa2, PANC1, CAPAN1, CFPAC1, and SU.86.86), the normal human pancreatic ductal epithelial cell line HPDE, and two pools of six pancreatic juice samples from ductal adenocarcinoma patients. All samples were analyzed in triplicate. Between 1261 and 2171 proteins were identified with two or more peptides in each of the cell lines, and an average of 521 proteins were identified in the pancreatic juice pools. In total, 3479 nonredundant proteins were identified with high confidence, of which ∼ 40% were extracellular or cell membrane-bound based on Genome Ontology classifications. Three strategies were employed for identification of candidate biomarkers: (1) examination of differential protein expression between the cancer and normal cell lines using label-free protein quantification, (2) integrative analysis, focusing on the overlap of proteins among the multiple biological fluids, and (3) tissue specificity analysis through mining of publically available databases. Preliminary verification of anterior gradient homolog 2, syncollin, olfactomedin-4, polymeric immunoglobulin receptor, and collagen alpha-1(VI) chain in plasma samples from pancreatic cancer patients and healthy controls using ELISA, showed a significant increase (p < 0.01) of these proteins in plasma from pancreatic cancer patients. The combination of these five proteins showed an improved area under the receiver operating characteristic curve to CA19.9 alone. Further validation of these proteins is warranted, as is the investigation of the remaining group of candidates.
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Affiliation(s)
- Shalini Makawita
- From the ‡Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- §Department of Clinical Biochemistry, University Health Network, Toronto, ON, Canada
| | - Chris Smith
- §Department of Clinical Biochemistry, University Health Network, Toronto, ON, Canada
| | - Ihor Batruch
- ¶Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, Canada
| | - Yingye Zheng
- ‖The Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Felix Rückert
- **Visceral, Thoracic and Vascular Surgery, University Hospital Carl Gustav Carus, Technical University of Dresden, Germany
| | - Robert Grützmann
- **Visceral, Thoracic and Vascular Surgery, University Hospital Carl Gustav Carus, Technical University of Dresden, Germany
| | - Christian Pilarsky
- **Visceral, Thoracic and Vascular Surgery, University Hospital Carl Gustav Carus, Technical University of Dresden, Germany
| | - Steven Gallinger
- ‡‡Zane Cohen Familial Gastrointestinal Cancer Registry and Department of Surgery, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Eleftherios P. Diamandis
- From the ‡Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- §Department of Clinical Biochemistry, University Health Network, Toronto, ON, Canada
- ¶Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, Canada
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Fletcher PL, Fletcher MD, Weninger K, Anderson TE, Martin BM. Vesicle-associated membrane protein (VAMP) cleavage by a new metalloprotease from the Brazilian scorpion Tityus serrulatus. J Biol Chem 2009; 285:7405-16. [PMID: 20026600 DOI: 10.1074/jbc.m109.028365] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We present evidence that venom from the Brazilian scorpion Tityus serrulatus and a purified fraction selectively cleave essential SNARE proteins within exocrine pancreatic tissue. Western blotting for vesicle-associated membrane protein type v-SNARE proteins (or synaptobrevins) reveals characteristic alterations to venom-treated excised pancreatic lobules in vitro. Immunocytochemistry by electron microscopy confirms both the SNARE identity as VAMP2 and the proteolysis of VAMP2 as a marked decrease in secondary antibody-conjugated colloidal gold particles that are predominantly associated with mature zymogen granules. Studies with recombinant SNARE proteins were used to determine the specific cleavage site in VAMP2 and the susceptibility of VAMP8 (endobrevin). The VAMP2 cleavage site is between the transmembrane anchor and the SNARE motif that assembles into the ternary SNARE complex. Inclusion of divalent chelating agents (EDTA) with fraction nu, an otherwise active purified component from venom, eliminates SNARE proteolysis, suggesting the active protein is a metalloprotease. The unique cleavages of VAMP2 and VAMP8 may be linked to pancreatitis that develops following scorpion envenomation as both of these v-SNARE proteins are associated with zymogen granule membranes in pancreatic acinar cells. We have isolated antarease, a metalloprotease from fraction nu that cleaves VAMP2, and report its amino acid sequence.
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Affiliation(s)
- Paul L Fletcher
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina 27834, USA
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Ohta E, Itoh T, Nemoto T, Kumagai J, Ko SBH, Ishibashi K, Ohno M, Uchida K, Ohta A, Sohara E, Uchida S, Sasaki S, Rai T. Pancreas-specific aquaporin 12 null mice showed increased susceptibility to caerulein-induced acute pancreatitis. Am J Physiol Cell Physiol 2009; 297:C1368-78. [DOI: 10.1152/ajpcell.00117.2009] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Aquaporin 12 (AQP12) is the most recently identified member of the mammalian AQP family and is specifically expressed in pancreatic acinar cells. In vitro expression studies have revealed that AQP12 is localized at intracellular sites. To determine the physiological roles of AQP12 in the pancreas, we generated knockout mice for this gene (AQP12-KO). No obvious differences were observed under normal conditions between wild-type (WT) and AQP12-KO mice in terms of growth, blood chemistry, pancreatic fluid content, or histology. However, when we induced pancreatitis through the administration of a cholecystokinin-8 (CCK-8) analog, the AQP12-KO mice showed more severe pathological damage to this organ than WT mice. Furthermore, when we analyzed exocytosis in the pancreatic acini using a two-photon excitation imaging method, the results revealed larger exocytotic vesicles (vacuoles) in the acini of AQP12-KO mice at a high CCK-8 dose (100 nM). From these results, we conclude that AQP12 may function in the mechanisms that control the proper secretion of pancreatic fluid following rapid and intense stimulation.
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Affiliation(s)
| | | | - Tomomi Nemoto
- Supportive Center for Brain Research, National Institute for Physiological Sciences and
- Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Okazaki
| | - Jiro Kumagai
- Department of Pathology, Tokyo Medical and Dental University, Tokyo
| | - Shigeru B. H. Ko
- Division of Gastroenterology, Department of Medicine, Nagoya University Graduate School of Medicine, Nagoya
| | - Kenichi Ishibashi
- Department of Medical Physiology, Meiji Pharmaceutical University, Tokyo
| | - Mayuko Ohno
- Department of Medicine, Kidney Center, Tokyo Women's Medical University, Tokyo, Japan
| | - Keiko Uchida
- Department of Medicine, Kidney Center, Tokyo Women's Medical University, Tokyo, Japan
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Niemann CU, Cowland JB, Ralfkiaer E, Åbrink M, Pejler G, Borregaard N. Serglycin proteoglycan is not implicated in localizing exocrine pancreas enzymes to zymogen granules. Eur J Cell Biol 2009; 88:473-9. [DOI: 10.1016/j.ejcb.2009.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 03/19/2009] [Accepted: 03/23/2009] [Indexed: 10/20/2022] Open
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Biogenesis of Dense-Core Secretory Granules. TRAFFICKING INSIDE CELLS 2009. [PMCID: PMC7122546 DOI: 10.1007/978-0-387-93877-6_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dense core granules (DCGs) are vesicular organelles derived from outbound traffic through the eukaryotic secretory pathway. As DCGs are formed, the secretory pathway can also give rise to other types of vesicles, such as those bound for endosomes, lysosomes, and the cell surface. DCGs differ from these other vesicular carriers in both content and function, storing highly concentrated cores’ of condensed cargo in vesicles that are stably maintained within the cell until a specific extracellular stimulus causes their fusion with the plasma membrane. These unique features are imparted by the activities of membrane and lumenal proteins that are specifically delivered to the vesicles during synthesis. This chapter will describe the DCG biogenesis pathway, beginning with the sorting of DCG proteins from proteins that are destined for other types of vesicle carriers. In the trans-Golgi network (TGN), sorting occurs as DCG proteins aggregate, causing physical separation from non-DCG proteins. Recent work addresses the nature of interactions that produce these aggregates, as well as potentially important interactions with membranes and membrane proteins. DCG proteins are released from the TGN in vesicles called immature secretory granules (ISGs). The mechanism of ISG formation is largely unclear but is not believed to rely on the assembly of vesicle coats like those observed in other secretory pathways. The required cytosolic factors are now beginning to be identified using in vitro systems with purified cellular components. ISG transformation into a mature fusion-competent, stimulus-dependent DCG occurs as endoproteolytic processing of many DCG proteins causes continued condensation of the lumenal contents. At the same time, proteins that fail to be incorporated into the condensing core are removed by a coat-mediated budding mechanism, which also serves to remove excess membrane and membrane proteins from the maturing vesicle. This chapter will summarize the work leading to our current view of granule synthesis, and will discuss questions that need to be addressed in order to gain a more complete understanding of the pathway.
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Chen X, Ulintz PJ, Simon ES, Williams JA, Andrews PC. Global topology analysis of pancreatic zymogen granule membrane proteins. Mol Cell Proteomics 2008; 7:2323-36. [PMID: 18682380 DOI: 10.1074/mcp.m700575-mcp200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The zymogen granule is the specialized organelle in pancreatic acinar cells for digestive enzyme storage and regulated secretion and is a classic model for studying secretory granule function. Our long term goal is to develop a comprehensive architectural model for zymogen granule membrane (ZGM) proteins that would direct new hypotheses for subsequent functional studies. Our initial proteomics analysis focused on identification of proteins from purified ZGM (Chen, X., Walker, A. K., Strahler, J. R., Simon, E. S., Tomanicek-Volk, S. L., Nelson, B. B., Hurley, M. C., Ernst, S. A., Williams, J. A., and Andrews, P. C. (2006) Organellar proteomics: analysis of pancreatic zymogen granule membranes. Mol. Cell. Proteomics 5, 306-312). In the current study, a new global topology analysis of ZGM proteins is described that applies isotope enrichment methods to a protease protection protocol. Our results showed that tryptic peptides of ZGM proteins were separated into two distinct clusters according to their isobaric tag for relative and absolute quantification (iTRAQ) ratios for proteinase K-treated versus control zymogen granules. The low iTRAQ ratio cluster included cytoplasm-orientated membrane and membrane-associated proteins including myosin V, vesicle-associated membrane proteins, syntaxins, and all the Rab proteins. The second cluster having unchanged ratios included predominantly luminal proteins. Because quantification is at the peptide level, this technique is also capable of mapping both cytoplasm- and lumen-orientated domains from the same transmembrane protein. To more accurately assign the topology, we developed a statistical mixture model to provide probabilities for identified peptides to be cytoplasmic or luminal based on their iTRAQ ratios. By implementing this approach to global topology analysis of ZGM proteins, we report here an experimentally constrained, comprehensive topology model of identified zymogen granule membrane proteins. This model contributes to a firm foundation for developing a higher order architecture model of the ZGM and for future functional studies of individual ZGM proteins.
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Affiliation(s)
- Xuequn Chen
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
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Rindler MJ, Xu CF, Gumper I, Smith NN, Neubert TA. Proteomic analysis of pancreatic zymogen granules: identification of new granule proteins. J Proteome Res 2007; 6:2978-92. [PMID: 17583932 PMCID: PMC2582026 DOI: 10.1021/pr0607029] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The composition of zymogen granules from rat pancreas was determined by LC-MS/MS. Enriched intragranular content, peripheral membrane, and integral membrane protein fractions were analyzed after one-dimensional SDS-PAGE and tryptic digestion of gel slices. A total of 371 proteins was identified with high confidence, including 84 previously identified granule proteins. The 287 remaining proteins included 37 GTP-binding proteins and effectors, 8 tetraspan membrane proteins, and 22 channels and transporters. Seven proteins, pantophysin, cyclic nucleotide phosphodiesterase, carboxypeptidase D, ecto-nucleotide phosphodiesterase 3, aminopeptidase N, ral, and the potassium channel TWIK-2, were confirmed by immunofluorescence microscopy or by immunoblotting to be new zymogen granule membrane proteins.
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Affiliation(s)
- Michael J Rindler
- Department of Cell Biology, New York University School of Medicine, New York, New York 10016, USA.
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Sherry DM, Mitchell R, Standifer KM, du Plessis B. Distribution of plasma membrane-associated syntaxins 1 through 4 indicates distinct trafficking functions in the synaptic layers of the mouse retina. BMC Neurosci 2006; 7:54. [PMID: 16839421 PMCID: PMC1555595 DOI: 10.1186/1471-2202-7-54] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Accepted: 07/13/2006] [Indexed: 01/02/2023] Open
Abstract
Background Syntaxins 1 through 4 are SNAP receptor (SNARE) proteins that mediate vesicular trafficking to the plasma membrane. In retina, syntaxins 1 and 3 are expressed at conventional and ribbon synapses, respectively, suggesting that synaptic trafficking functions differ among syntaxin isoforms. To better understand syntaxins in synaptic signaling and trafficking, we further examined the cell- and synapse-specific expression of syntaxins 1 through 4 in the mouse retina by immunolabeling and confocal microscopy. Results Each isoform was expressed in the retina and showed a unique distribution in the synaptic layers of the retina, with little or no colocalization of isoforms. Syntaxin 1 was present in amacrine cell bodies and processes and conventional presynaptic terminals in the inner plexiform layer (IPL). Syntaxin 2 was present in amacrine cells and their processes in the IPL, but showed little colocalization with syntaxin 1 or other presynaptic markers. Syntaxin 3 was found in glutamatergic photoreceptor and bipolar cell ribbon synapses, but was absent from putative conventional glutamatergic amacrine cell synapses. Syntaxin 4 was localized to horizontal cell processes in the ribbon synaptic complexes of photoreceptor terminals and in puncta in the IPL that contacted dopaminergic and CD15-positive amacrine cells. Syntaxins 2 and 4 often were apposed to synaptic active zones labeled for bassoon. Conclusion These results indicate that each syntaxin isoform has unique, non-redundant functions in synaptic signaling and trafficking. Syntaxins 1 and 3 mediate presynaptic transmitter release from conventional and ribbon synapses, respectively. Syntaxins 2 and 4 are not presynaptic and likely mediate post-synaptic trafficking.
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Affiliation(s)
- David M Sherry
- University of Houston, College of Optometry, Houston, TX 77204, USA
- College of Pharmacy, Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77204, USA
| | - Robert Mitchell
- University of Houston, College of Optometry, Houston, TX 77204, USA
| | - Kelly M Standifer
- College of Pharmacy, Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77204, USA
| | - Brad du Plessis
- University of Houston, College of Optometry, Houston, TX 77204, USA
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16
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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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17
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Dahan S, Anderson KL, Weller S, Krueger E, McNiven MA. Agonist-induced vesiculation of the Golgi apparatus in pancreatic acinar cells. Gastroenterology 2005; 129:2032-46. [PMID: 16344069 DOI: 10.1053/j.gastro.2005.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2002] [Accepted: 08/31/2005] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS The pancreatic acinar cell is known to regulate exocytosis, total protein synthesis, and secretory protein transport in response to a secretory stimulus. Whether secretory vesicle formation also is regulated is unclear. In this study, we determined whether agonist stimulation induces morphologic alterations in the acinar cell Golgi apparatus, and we evaluated the role of the vesicle severing protein dynamin. METHODS Changes in Golgi structural integrity by examining the distribution of various Golgi and TGN lipid and protein markers in live and fixed cells on stimulation with cholecystokinin were noted in a primary pancreatic acinar cell model. Multiple dynamin reagents were used to examine the distribution and function of this molecular pinchase in resting and stimulated cells. RESULTS Regulated secretion in acinar cells induced (1) marked fragmentation of the trans-Golgi network (TGN) that corresponded temporally with an increase in cytoplasmic calcium whereas pre-TGN compartments of the Golgi and regions of the TGN involved in the generation of constitutively trafficking vesicles were unaffected by agonist, and (2) significant recruitment of dynamin to the acinar cell Golgi apparatus that appeared to potentiate fragmentation of the TGN. CONCLUSIONS These results suggest that the TGN is a dynamic organelle that fragments in response to cholecystokinin stimulation, a process that may contribute to zymogen granule formation.
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Affiliation(s)
- Sophie Dahan
- Center for Basic Research in Digestive Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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18
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Wäsle B, Turvey M, Larina O, Thorn P, Skepper J, Morton A, Edwardson J. Syncollin is required for efficient zymogen granule exocytosis. Biochem J 2005; 385:721-7. [PMID: 15462671 PMCID: PMC1134747 DOI: 10.1042/bj20041064] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Syncollin is a 13 kDa protein that is present in the exocrine pancreas, where the majority of the protein is tightly attached to the luminal surface of the zymogen granule membrane. We have addressed the physiological role of syncollin by studying the phenotype of syncollin KO (knockout) mice. These mice show pancreatic hypertrophy and elevated pancreatic amylase levels. Further, secretagogue-stimulated amylase release from pancreatic lobules of syncollin KO mice was found to be reduced by about 45% compared with wild-type lobules, and the delivery of newly synthesized protein to zymogen granules was delayed, indicating that the mice have a pancreatic secretory defect. As determined by two-photon imaging, the number of secretagogue-stimulated exocytotic events in acini from syncollin KO mice was reduced by 50%. This reduction was accounted for predominantly by a loss of later, 'secondary' fusion events between zymogen granules and other granules that had already fused with the plasma membrane. We conclude that syncollin is required for efficient exocytosis in the pancreatic acinar cell, and that it plays a particularly important role in compound exocytosis.
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Affiliation(s)
- Barbara Wäsle
- *Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Matthew Turvey
- *Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Olga Larina
- *Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Peter Thorn
- *Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Jeremy Skepper
- †Multi-Imaging Centre, Department of Anatomy, University of Cambridge, Downing Street, Cambridge CB2 3DY, U.K
| | - A. Jennifer Morton
- *Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - J. Michael Edwardson
- *Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
- To whom correspondence should be addressed (email )
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19
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Grønborg M, Bunkenborg J, Kristiansen TZ, Jensen ON, Yeo CJ, Hruban RH, Maitra A, Goggins MG, Pandey A. Comprehensive proteomic analysis of human pancreatic juice. J Proteome Res 2005; 3:1042-55. [PMID: 15473694 DOI: 10.1021/pr0499085] [Citation(s) in RCA: 173] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Proteomic technologies provide an excellent means for analysis of body fluids for cataloging protein constituents and identifying biomarkers for early detection of cancers. The biomarkers currently available for pancreatic cancer, such as CA19-9, lack adequate sensitivity and specificity contributing to late diagnosis of this deadly disease. In this study, we carried out a comprehensive characterization of the "pancreatic juice proteome" in patients with pancreatic adenocarcinoma. Pancreatic juice was first fractionated by 1-dimensional gel electrophoresis and subsequently analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). A total of 170 unique proteins were identified including known pancreatic cancer tumor markers (e.g., CEA, MUC1) and proteins overexpressed in pancreatic cancers (e.g., hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein (HIP/PAP) and lipocalin 2). In addition, we identified a number of proteins that have not been previously described in pancreatic juice (e.g., tumor rejection antigen (pg96) and azurocidin). Interestingly, a novel protein that is 85% identical to HIP/PAP was identified, which we have designated as PAP-2. The proteins identified in this study could be directly assessed for their potential as biomarkers for pancreatic cancer by quantitative proteomics methods or immunoassays.
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MESH Headings
- Agglutinins/analysis
- Agglutinins/genetics
- Agglutinins/metabolism
- Amino Acid Sequence
- Antigens, Neoplasm/analysis
- Antigens, Neoplasm/genetics
- Antigens, Neoplasm/metabolism
- Antimicrobial Cationic Peptides
- Biomarkers, Tumor/analysis
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Blood Proteins/analysis
- Blood Proteins/metabolism
- Calcium-Binding Proteins/genetics
- Carrier Proteins/analysis
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cell Adhesion Molecules/analysis
- Cell Adhesion Molecules/genetics
- Cell Adhesion Molecules/metabolism
- Chromatography, Liquid
- DNA-Binding Proteins
- Electrophoresis, Polyacrylamide Gel
- Gene Expression/genetics
- Glycoproteins/genetics
- Humans
- Lectins, C-Type/analysis
- Lectins, C-Type/genetics
- Lectins, C-Type/metabolism
- Lithostathine
- Mass Spectrometry
- Membrane Proteins/analysis
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Molecular Sequence Data
- Pancreatic Juice/chemistry
- Pancreatic Juice/metabolism
- Pancreatic Neoplasms/metabolism
- Pancreatitis-Associated Proteins
- Peptide Fragments/analysis
- Phylogeny
- Proteome/analysis
- Proteome/classification
- Proteome/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cell Surface/analysis
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Sequence Alignment
- Sequence Homology, Amino Acid
- Trypsin/metabolism
- Tumor Suppressor Proteins
- alpha-Defensins/analysis
- alpha-Defensins/genetics
- alpha-Defensins/metabolism
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Affiliation(s)
- Mads Grønborg
- McKusick-Nathans Institute of Genetic Medicine and Department of Biological Chemistry, Johns Hopkins University, Baltimore, Maryland 21205, USA
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20
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Wäsle B, Hays LB, Rhodes CJ, Edwardson JM. Syncollin inhibits regulated corticotropin secretion from AtT-20 cells through a reduction in the secretory vesicle population. Biochem J 2004; 380:897-905. [PMID: 15040787 PMCID: PMC1224234 DOI: 10.1042/bj20031726] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2003] [Revised: 03/23/2004] [Accepted: 03/24/2004] [Indexed: 11/17/2022]
Abstract
Syncollin is a 13 kDa protein that is highly expressed in the exocrine pancreas. Syncollin normally exists as a doughnut-shaped homo-oligomer (quite probably a hexamer) in close association with the luminal surface of the zymogen granule membrane. In the present study, we examine the effect of expression of syncollin in AtT-20 neuroendocrine cells, which do not normally express this protein. Efficient expression was achieved by infection of the cells with adenoviral constructs encoding either untagged or GFP (green fluorescent protein)-tagged syncollin. Both forms of the protein were sorted into corticotropin (ACTH)-positive secretory vesicles present mainly at the tips of cell processes. Neither form affected basal corticotropin secretion or the constitutive secretion of exogenously expressed secreted alkaline phosphatase. In contrast, regulated secretion of corticotropin was inhibited (by 49%) by untagged but not by GFP-tagged syncollin. In parallel, untagged syncollin caused a 46% reduction in the number of secretory vesicles present at the tips of the cell processes. Syncollin-GFP was without effect. We could also show that native syncollin purified from rat pancreas was capable of permeabilizing erythrocytes. We suggest that syncollin may induce uncontrolled permeabilization of corticotropin-containing vesicles and subsequently destabilize them. Both forms of syncollin were tightly membrane-associated and appeared to exist as homooligomers. Hence, the lack of effect of syncollin-GFP on regulated exocytosis suggests that the GFP tag interferes in a subtler manner with the properties of the assembled protein.
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Affiliation(s)
- Barbara Wäsle
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
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21
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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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22
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Abstract
PURPOSE OF REVIEW Secretagogue receptors and their intracellular signaling pathways regulate pancreatic physiology and may be altered in pathophysiology. Therefore, understanding of the continued progress into their nature and function is relevant to both biology and disease. RECENT FINDINGS The major secretagogue receptors on acinar cells include those binding cholecystokinin and acetylcholine, whereas secretin receptors regulate duct cells. Two physical models of the cholecystokinin receptor and ligand binding have been proposed through extensive structure-activity studies. Receptor oligomerization has been described for both cholecystokinin and secretin receptors. Ca plays a central role in the control of digestive enzyme secretion and is largely mobilized from intracellular stores. Inositol trisphosphate has been joined by two other Ca-releasing messengers, cyclic ADP ribose and nicotinic acid adenine dinucleotide phosphate, in initiating and coordinating Ca signaling. Progress has also been made in determining the roles of specific organelles in Ca release. Ca triggers secretion, and knowledge of the function and regulation of the proteins involved in exocytosis is accumulating. Continuing advances have also been made in understanding the signaling pathways regulating protein synthesis and growth in adult pancreas. The protein kinase mammalian target of rapamycin and its downstream targets play a central role in protein synthesis, whereas the protein phosphatase calcineurin was recently reported to regulate pancreatic growth. Other signaling molecules include the MAP kinases, PKCs, cytoplasmic tyrosine kinases, and nitric oxide. SUMMARY The current findings reviewed here are illuminating the structure and function of receptors on pancreatic acinar and duct cells and the multiple intracellular signaling pathways that they initiate. Understanding of these mechanisms is contributing to knowledge of normal pancreatic functions and alterations in disease such as pancreatitis and pancreatic cancer.
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Affiliation(s)
- Yan Bi
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109-0622, USA
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23
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Abstract
Regulated secretion and exocytosis require the selective packaging of regulated secretory proteins in secretory storage organelles and the controlled docking and fusion of these organelles with the plasma membrane. Secretory granule biogenesis involves sorting of secretory proteins and membrane components both at the level of the trans-Golgi network and the immature secretory granule. Sorting is thought to be mediated by selective protein aggregation and the interaction of these proteins with specific membrane domains. There is now considerable interest in the understanding of the complex lipid-protein and protein-protein interactions at the trans-Golgi network and the granule membrane. A role for lipid microdomains and associated sorting receptors in membrane targeting and granule formation is vividly discussed for (neuro)endocrine cells. In exocrine cells, however, little has been known of granule membrane composition and membrane protein function. With the cloning and characterization of granule membrane proteins and their interactions at the inner leaflet of zymogen granules of pancreatic acinar cells, it is now possible to elucidate their function in membrane targeting and sorting of zymogens at the molecular level.
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Affiliation(s)
- Michael Schrader
- Department of Cell Biology and Cell Pathology, University of Marburg, Robert Koch Str 6, 35037 Marburg, Germany
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24
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Shimada O, Hara-Kuge S, Yamashita K, Tosaka-Shimada H, Yanchao L, Einan L, Atsumi S, Ishikawa H. Localization of VIP36 in the post-Golgi secretory pathway also of rat parotid acinar cells. J Histochem Cytochem 2003; 51:1057-63. [PMID: 12871987 DOI: 10.1177/002215540305100809] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
VIP36 (36-kD vesicular integral membrane protein), originally purified from Madin-Darby canine kidney (MDCK) epithelial cells, belongs to a family of animal lectins and may act as a cargo receptor. To understand its role in secretory processes, we performed morphological analysis of the rat parotid gland. Immunoelectron microscopy provided evidence that endogenous VIP36 is localized in the trans-Golgi network, on immature granules, and on mature secretory granules in acinar cells. Double-staining immunofluorescence experiments confirmed that VIP36 and amylase co-localized in the apical regions of the acinar cells. This is the first study to demonstrate that endogenous VIP36 is involved in the post-Golgi secretory pathway, suggesting that VIP36 plays a role in trafficking and sorting of secretory and/or membrane proteins during granule formation.
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Affiliation(s)
- Osamu Shimada
- Department of Anatomy, Yamanashi University School of Medicine, Yamanashi, Japan.
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25
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Riedel D, Antonin W, Fernandez-Chacon R, Alvarez de Toledo G, Jo T, Geppert M, Valentijn JA, Valentijn K, Jamieson JD, Südhof TC, Jahn R. Rab3D is not required for exocrine exocytosis but for maintenance of normally sized secretory granules. Mol Cell Biol 2002; 22:6487-97. [PMID: 12192047 PMCID: PMC135623 DOI: 10.1128/mcb.22.18.6487-6497.2002] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rab3D, a member of the Rab3 subfamily of the Rab/ypt GTPases, is expressed on zymogen granules in the pancreas as well as on secretory vesicles in mast cells and in the parotid gland. To shed light on the function of Rab3D, we have generated Rab3D-deficient mice. These mice are viable and have no obvious phenotypic changes. Secretion of mast cells is normal as revealed by capacitance patch clamping. Furthermore, enzyme content and overall morphology are unchanged in pancreatic and parotid acinar cells of knockout mice. Both the exocrine pancreas and the parotid gland show normal release kinetics in response to secretagogue stimulation, suggesting that Rab3D is not involved in exocytosis. However, the size of secretory granules in both the exocrine pancreas and the parotid gland is significantly increased, with the volume being doubled. We conclude that Rab3D exerts its function during granule maturation, possibly by preventing homotypic fusion of secretory granules.
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Affiliation(s)
- Dietmar Riedel
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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