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Yang S, Zhou P, Zhang L, Xie X, Zhang Y, Bo K, Xue J, Zhang W, Liao F, Xu P, Hu Y, Yan R, Liu D, Chang J, Zhou K. VAMP8 suppresses the metastasis via DDX5/β-catenin signal pathway in osteosarcoma. Cancer Biol Ther 2023; 24:2230641. [PMID: 37405957 DOI: 10.1080/15384047.2023.2230641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 06/16/2023] [Accepted: 06/22/2023] [Indexed: 07/07/2023] Open
Abstract
Osteosarcoma is a highly metastatic malignant bone tumor, necessitating the development of new treatments to target its metastasis. Recent studies have revealed the significance of VAMP8 in regulating various signaling pathways in various types of cancer. However, the specific functional role of VAMP8 in osteosarcoma progression remains unclear. In this study, we observed a significant downregulation of VAMP8 in osteosarcoma cells and tissues. Low levels of VAMP8 in osteosarcoma tissues were associated with patients' poor prognosis. VAMP8 inhibited the migration and invasion capability of osteosarcoma cells. Mechanically, we identified DDX5 as a novel interacting partner of VAMP8, and the conjunction of VAMP8 and DDX5 promoted the degradation of DDX5 via the ubiquitin-proteasome system. Moreover, reduced levels of DDX5 led to the downregulation of β-catenin, thereby suppressing the epithelial-mesenchymal transition (EMT). Additionally, VAMP8 promoted autophagy flux, which may contribute to the suppression of osteosarcoma metastasis. In conclusion, our study anticipated that VAMP8 inhibits osteosarcoma metastasis by promoting the proteasomal degradation of DDX5, consequently inhibiting WNT/β-catenin signaling and EMT. Dysregulation of autophagy by VAMP8 is also implicated as a potential mechanism. These findings provide new insights into the biological nature driving osteosarcoma metastasis and highlight the modulation of VAMP8 as a potential therapeutic strategy for targeting osteosarcoma metastasis.
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Affiliation(s)
- Shuo Yang
- Department of Orthopaedics, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Department of Orthopaedics, Anhui Public Health Clinical Center, Hefei, China
| | - Ping Zhou
- Department of Orthopaedics, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Department of Orthopaedics, Anhui Public Health Clinical Center, Hefei, China
| | - Lelei Zhang
- Department of Orthopaedics, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Department of Orthopaedics, Anhui Public Health Clinical Center, Hefei, China
| | - Xiangpeng Xie
- Department of Orthopaedics, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Department of Orthopaedics, Anhui Public Health Clinical Center, Hefei, China
| | - Yuanyi Zhang
- Department of Orthopaedics, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Department of Orthopaedics, Anhui Public Health Clinical Center, Hefei, China
| | - Kaida Bo
- Department of Orthopaedics, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Department of Orthopaedics, Anhui Public Health Clinical Center, Hefei, China
| | - Jing Xue
- Department of Orthopaedics, Anhui Public Health Clinical Center, Hefei, China
- Clinical Pathology Center, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Wei Zhang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Faxue Liao
- Department of Orthopaedics, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Department of Orthopaedics, Anhui Public Health Clinical Center, Hefei, China
| | - Pengfei Xu
- Department of Orthopaedics, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Department of Orthopaedics, Anhui Public Health Clinical Center, Hefei, China
| | - Yong Hu
- Department of Orthopaedics, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Ruyu Yan
- Cancer Metabolism Laboratory, School of Life Sciences, Anhui Medical University, Hefei, China
| | - Dan Liu
- Cancer Metabolism Laboratory, School of Life Sciences, Anhui Medical University, Hefei, China
| | - Jun Chang
- Department of Orthopaedics, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Department of Orthopaedics, Anhui Public Health Clinical Center, Hefei, China
| | - Kecheng Zhou
- Department of Orthopaedics, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Department of Orthopaedics, Anhui Public Health Clinical Center, Hefei, China
- Cancer Metabolism Laboratory, School of Life Sciences, Anhui Medical University, Hefei, China
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Adhikari P, Ayo TE, Vines JC, Sugita S, Xu H. Exocytic machineries differentially control mediator release from allergen-triggered RBL-2H3 cells. Inflamm Res 2023; 72:639-649. [PMID: 36725743 DOI: 10.1007/s00011-023-01698-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 01/06/2023] [Accepted: 01/23/2023] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Mast cells utilize SNAREs (soluble-N-ethyl-maleimide sensitive factor attachment protein receptors) and SM (Sec1/Munc18) proteins to secrete/exocytose a variety of proinflammatory mediators. However, whether a common SNARE-SM machinery is responsible remains unclear. METHODS Four vesicle/granule-anchored SNAREs (VAMP2, VAMP3, VAMP7, and VAMP8) and two Munc18 homologs (Munc18a and Munc18b) were systematically knocked down or knocked out in RBL-2H3 mast cells and antigen-induced release of β-hexosaminidase, histamine, serotonin, and TNF was examined. Phenotypes were validated by rescue experiments. Immunofluorescence studies were performed to determine the subcellular distribution of key players. RESULTS The reduction of VAMP8 expression inhibited the exocytosis of β-hexosaminidase, histamine, and serotonin but not TNF. Unexpectedly, however, confocal microscopy revealed substantial co-localization between VAMP8 and TNF, and between TNF and serotonin. Meanwhile, the depletion of other VAMPs, including knockout of VAMP3, had no impact on the release of any of the mediators examined. On the other hand, TNF exocytosis was diminished specifically in stable Munc18bknockdown cells, in a fashion that was rescued by exogenous, RNAi-resistant Munc18b. In line with this, TNF was co-localized with Munc18b (47%) to a much greater extent than with Munc18a (13%). CONCLUSION Distinct exocytic pathways exist in mast cells for the release of different mediators.
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Affiliation(s)
- Pratikshya Adhikari
- Center for Molecular and Cellular Biosciences, School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - Tolulope E Ayo
- Center for Molecular and Cellular Biosciences, School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - John C Vines
- Center for Molecular and Cellular Biosciences, School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - Shuzo Sugita
- Division of Fundamental Neurobiology, University Health Network, Toronto, ON, M5T 2S8, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Hao Xu
- Center for Molecular and Cellular Biosciences, School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
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Weimershaus M, Carvalho C, Rignault R, Waeckel-Enee E, Dussiot M, van Endert P, Maciel TT, Hermine O. Mast cell-mediated inflammation relies on insulin-regulated aminopeptidase controlling cytokine export from the Golgi. J Allergy Clin Immunol 2023:S0091-6749(23)00090-8. [PMID: 36708814 DOI: 10.1016/j.jaci.2023.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 12/31/2022] [Accepted: 01/11/2023] [Indexed: 01/26/2023]
Abstract
BACKGROUND On activation, mast cells rapidly release preformed inflammatory mediators from large cytoplasmic granules via regulated exocytosis. This acute degranulation is followed by a late activation phase involving synthesis and secretion of cytokines, growth factors, and other inflammatory molecules via the constitutive pathway that remains ill defined. OBJECTIVE We investigated the role for an insulin-responsive vesicle-like endosomal compartment, marked by insulin-regulated aminopeptidase (IRAP), in the secretion of TNF-α and IL-6 in mast cells and macrophages. METHODS Murine knockout (KO) mouse models (IRAP-KO and kit-Wsh/sh) were used to study inflammatory disease models and to measure and mechanistically investigate cytokine secretion and degranulation in bone marrow-derived mast cells in vitro. RESULTS IRAP-KO mice are protected from TNF-α-dependent kidney injury and inflammatory arthritis. In the absence of IRAP, TNF-α and IL-6 but not IL-10 fail to be efficiently secreted. Moreover, chemical targeting of IRAP endosomes reduced proinflammatory cytokine secretion. Mechanistically, impaired TNF-α export from the Golgi and reduced colocalization of vesicle-associated membrane protein (VAMP) 3-positive TNF-α transport vesicles with syntaxin 4 (aka Stx4) was observed in IRAP-KO mast cells, while VAMP8-dependent exocytosis of secretory granules was facilitated. CONCLUSION IRAP plays a novel role in mast cell-mediated inflammation through the regulation of exocytic trafficking of cytokines.
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Affiliation(s)
- Mirjana Weimershaus
- Imagine Institute, Laboratory of Cellular and Molecular Mechanisms of Hematological Disorders and Therapeutic Implications, INSERM U1163, F-75015, Paris, France.
| | - Caroline Carvalho
- Imagine Institute, Laboratory of Cellular and Molecular Mechanisms of Hematological Disorders and Therapeutic Implications, INSERM U1163, F-75015, Paris, France
| | - Rachel Rignault
- Imagine Institute, Laboratory of Cellular and Molecular Mechanisms of Hematological Disorders and Therapeutic Implications, INSERM U1163, F-75015, Paris, France; Université de Paris Cité, Paris, France
| | | | - Michael Dussiot
- Imagine Institute, Laboratory of Cellular and Molecular Mechanisms of Hematological Disorders and Therapeutic Implications, INSERM U1163, F-75015, Paris, France; Université de Paris Cité, Paris, France; Laboratory of Excellence GR-Ex, Paris, France
| | - Peter van Endert
- INSERM UMR 1151, CNRS UMR 8253, Paris, France; Université de Paris Cité, Paris, France
| | - Thiago Trovati Maciel
- Imagine Institute, Laboratory of Cellular and Molecular Mechanisms of Hematological Disorders and Therapeutic Implications, INSERM U1163, F-75015, Paris, France; Laboratory of Excellence GR-Ex, Paris, France
| | - Olivier Hermine
- Imagine Institute, Laboratory of Cellular and Molecular Mechanisms of Hematological Disorders and Therapeutic Implications, INSERM U1163, F-75015, Paris, France; Université de Paris Cité, Paris, France; Hôpital Necker Enfants Malades, Paris, France; Laboratory of Excellence GR-Ex, Paris, France
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Abstract
The STX17-SNAP29-VAMP8 SNARE complex mediates autophagosome-lysosome fusion. Our recent study showed that MTOR directly phosphorylates VAMP8's T48 residue in nutrient-rich conditions. Phosphorylated VAMP8 inhibits autophagosome-lysosome fusion by blocking STX17-SNAP29-VAMP8 SNARE complex formation. Our study also showed that SCFD1 is a previously unrecognized macroautophagy/autophagy regulatory protein, which can be recruited by VAMP8 (in its non-phosphorylated form) to autolysosomes, where it promotes STX17-SNAP29-VAMP8 complex assembly - and consequently promotes autophagosome-lysosome fusion. Moreover, we observed that mice harboring a phosphomimic VAMP8 variant accumulate aberrantly high lipid levels in their livers. VAMP8 phosphorylation can disrupt autophagosome-lysosome fusion in the liver and thereby dysregulate lipid metabolism. Beyond providing insights into the molecular mechanisms of autophagosome maturation, our study suggests that modulating autophagic SNARE function may help treat liver lipid disorders.
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Affiliation(s)
- Qinqin Ouyang
- College of Food Science and Technology, School of Life Sciences, Nanjing Agricultural University, Nanjing, China,National Center for International Research on Animal Gut Nutrition, Jiangsu Collaborative Innovation Center of Meat Production and Processing Nanjing Agricultural University, Nanjing, China
| | - Rong Liu
- College of Food Science and Technology, School of Life Sciences, Nanjing Agricultural University, Nanjing, China,National Center for International Research on Animal Gut Nutrition, Jiangsu Collaborative Innovation Center of Meat Production and Processing Nanjing Agricultural University, Nanjing, China,CONTACT Rong Liu National Center for International Research on Animal Gut Nutrition, Jiangsu Collaborative Innovation Center of Meat Production and Processing Nanjing Agricultural University, Nanjing210095, China
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Abstract
In the final critical step for autophagic degradation, lysosomes fuse with autophagosomes to form autolysosomes. Although recent research has suggested that soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins are important for lysosome-autophagosome fusion, neither the architecture of the prefusion state nor the regulatory mechanisms have been identified. In our study, using structured illumination microscopy, we observed that lysosomes formed clusters around individual autophagosomes, thereby setting the stage for membrane fusion. Moreover, VAMP8 (vesicle-associated membrane protein 8) assists in forming the prefusion state of these clusters. We also found that VAMP8 phosphorylation reduces spontaneous lysosome-autophagosome fusion, whereas its dephosphorylation promotes fusion events between lysosomes and autophagosomes in both normal and autophagy-induced conditions. Our data thus suggest a key role of VAMP8 phosphorylation in the regulation of lysosome-autophagosome fusion.
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Affiliation(s)
- Lei Wang
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
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Lauzier A, Bossanyi MF, Larcher R, Nassari S, Ugrankar R, Henne WM, Jean S. Snazarus and its human ortholog SNX25 modulate autophagic flux. J Cell Sci 2022; 135:273525. [PMID: 34821359 DOI: 10.1242/jcs.258733] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 11/12/2021] [Indexed: 12/26/2022] Open
Abstract
Macroautophagy, the degradation and recycling of cytosolic components in the lysosome, is an important cellular mechanism. It is a membrane-mediated process that is linked to vesicular trafficking events. The sorting nexin (SNX) protein family controls the sorting of a large array of cargoes, and various SNXs impact autophagy. To improve our understanding of their functions in vivo, we screened all Drosophila SNXs using inducible RNA interference in the fat body. Significantly, depletion of Snazarus (Snz) led to decreased autophagic flux. Interestingly, we observed altered distribution of Vamp7-positive vesicles with Snz depletion, and the roles of Snz were conserved in human cells. SNX25, the closest human ortholog to Snz, regulates both VAMP8 endocytosis and lipid metabolism. Through knockout-rescue experiments, we demonstrate that these activities are dependent on specific SNX25 domains and that the autophagic defects seen upon SNX25 loss can be rescued by ethanolamine addition. We also demonstrate the presence of differentially spliced forms of SNX14 and SNX25 in cancer cells. This work identifies a conserved role for Snz/SNX25 as a regulator of autophagic flux and reveals differential isoform expression between paralogs.
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Affiliation(s)
- Annie Lauzier
- Faculté de Médecine et des Sciences de la Santé, Département d'immunologie et de biologie cellulaire, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, Québec, CanadaJ1E 4K8
| | - Marie-France Bossanyi
- Faculté de Médecine et des Sciences de la Santé, Département d'immunologie et de biologie cellulaire, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, Québec, CanadaJ1E 4K8
| | - Raphaëlle Larcher
- Faculté de Médecine et des Sciences de la Santé, Département d'immunologie et de biologie cellulaire, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, Québec, CanadaJ1E 4K8
| | - Sonya Nassari
- Faculté de Médecine et des Sciences de la Santé, Département d'immunologie et de biologie cellulaire, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, Québec, CanadaJ1E 4K8
| | - Rupali Ugrankar
- Department of Cell Biology, UT Southwestern Medical Center, 6000 Hary Lines Boulevard, Dallas, TX 75390, USA
| | - W Mike Henne
- Department of Cell Biology, UT Southwestern Medical Center, 6000 Hary Lines Boulevard, Dallas, TX 75390, USA
| | - Steve Jean
- Faculté de Médecine et des Sciences de la Santé, Département d'immunologie et de biologie cellulaire, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, Québec, CanadaJ1E 4K8
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Pilliod J, Desjardins A, Pernègre C, Jamann H, Larochelle C, Fon EA, Leclerc N. Clearance of intracellular tau protein from neuronal cells via VAMP8-induced secretion. J Biol Chem 2021; 295:17827-17841. [PMID: 33454017 DOI: 10.1074/jbc.ra120.013553] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 10/03/2020] [Indexed: 11/06/2022] Open
Abstract
In Alzheimer's disease (AD), tau, a microtubule-associated protein (MAP), becomes hyperphosphorylated, aggregates, and accumulates in the somato-dendritic compartment of neurons. In parallel to its intracellular accumulation in AD, tau is also released in the extracellular space, as revealed by its increased presence in cerebrospinal fluid (CSF). Consistent with this, recent studies, including ours, have reported that neurons secrete tau, and several therapeutic strategies aim to prevent the intracellular tau accumulation. Previously, we reported that late endosomes were implicated in tau secretion. Here, we explore the possibility of preventing intracellular tau accumulation by increasing tau secretion. Using neuronal models, we investigated whether overexpression of the vesicle-associated membrane protein 8 (VAMP8), an R-SNARE found on late endosomes, could increase tau secretion. The overexpression of VAMP8 significantly increased tau secretion, decreasing its intracellular levels in the neuroblastoma (N2a) cell line. Increased tau secretion by VAMP8 was also observed in murine hippocampal slices. The intracellular reduction of tau by VAMP8 overexpression correlated to a decrease of acetylated tubulin induced by tau overexpression in N2a cells. VAMP8 staining was preferentially found on late endosomes in N2a cells. Using total internal reflection fluorescence (TIRF) microscopy, the fusion of VAMP8-positive vesicles with the plasma membrane was correlated to the depletion of tau in the cytoplasm. Finally, overexpression of VAMP8 reduced the intracellular accumulation of tau mutants linked to frontotemporal dementia with parkinsonism and α-synuclein by increasing their secretion. Collectively, the present data indicate that VAMP8 could be used to increase tau and α-synuclein clearance to prevent their intracellular accumulation.
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Affiliation(s)
- Julie Pilliod
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, Canada
| | - Alexandre Desjardins
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, Canada
| | - Camille Pernègre
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, Canada; Département de Neurosciences, Faculté de Médecine, Université de Montréal, Montréal, Canada
| | - Hélène Jamann
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, Canada; Département de Neurosciences, Faculté de Médecine, Université de Montréal, Montréal, Canada
| | - Catherine Larochelle
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, Canada; Département de Neurosciences, Faculté de Médecine, Université de Montréal, Montréal, Canada
| | - Edward A Fon
- McGill Parkinson Program, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montréal, Canada
| | - Nicole Leclerc
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, Canada; Département de Neurosciences, Faculté de Médecine, Université de Montréal, Montréal, Canada.
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Cao J, Tang Z, Su Z. Long non-coding RNA LINC01426 facilitates glioblastoma progression via sponging miR-345-3p and upregulation of VAMP8. Cancer Cell Int 2020; 20:327. [PMID: 32699526 PMCID: PMC7372762 DOI: 10.1186/s12935-020-01416-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 07/13/2020] [Indexed: 12/16/2022] Open
Abstract
Background Long non-coding RNAs (lncRNAs) has been extensively reported play important roles in regulating the development and progression of cancers, including Glioblastoma (GBM). LINC01426 is a novel lncRNA that has been identified as an oncogenic gene in GBM. Herein, we attempted to elucidate the detailed functions and underlying mechanisms of LINC01426 in GBM. Methods LINC01426 expression in GBM cell lines and tissues were detected by quantitative real-time PCR (qRT-PCR). Cell Counting Kit-8 (CCK8) assays, colony formation assays, subcutaneous tumor formation assays were utilized to investigate the biological functions of LINC01426 in GBM. Dual-luciferase reporter assays, RNA immunoprecipitation (RIP) and bioinformatic analysis were performed to determine the underlying mechanisms. Results LINC01426 is up-regulated in malignant GBM tissues and cell lines and it is capable to promote GBM cell proliferation and growth. Mechanistically, LINC01426 serves as a molecular sponge to sequester the miR345-3p and thus enhancing the level of VAMP8, an oncogenic coding gene, to promote GBM progression. Conclusions Our results revealed the detailed mechanisms of LINC01426 facilitated cell proliferation and growth in GBM and report the clinical value of LINC01426 for GBM prognosis and treatment.
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Affiliation(s)
- Jingwei Cao
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, No. 23 Youzheng Street, Nangang District, Harbin, 150001 Heilongjiang China
| | - Zhanbin Tang
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, No. 23 Youzheng Street, Nangang District, Harbin, 150001 Heilongjiang China
| | - Zhiqiang Su
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, No. 23 Youzheng Street, Nangang District, Harbin, 150001 Heilongjiang China
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van Tol S, Atkins C, Bharaj P, Johnson KN, Hage A, Freiberg AN, Rajsbaum R. VAMP8 Contributes to the TRIM6-Mediated Type I Interferon Antiviral Response during West Nile Virus Infection. J Virol 2020; 94:e01454-19. [PMID: 31694946 PMCID: PMC6955268 DOI: 10.1128/jvi.01454-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/23/2019] [Indexed: 11/20/2022] Open
Abstract
Several members of the tripartite motif (TRIM) family of E3 ubiquitin ligases regulate immune pathways, including the antiviral type I interferon (IFN-I) system. Previously, we demonstrated that TRIM6 is involved in IFN-I induction and signaling. In the absence of TRIM6, optimal IFN-I signaling is reduced, allowing increased replication of interferon-sensitive viruses. Despite having evolved numerous mechanisms to restrict the vertebrate host's IFN-I response, West Nile virus (WNV) replication is sensitive to pretreatment with IFN-I. However, the regulators and products of the IFN-I pathway that are important in regulating WNV replication are incompletely defined. Consistent with WNV's sensitivity to IFN-I, we found that in TRIM6 knockout (TRIM6-KO) A549 cells, WNV replication is significantly increased and IFN-I induction and signaling are impaired compared to wild-type (wt) cells. IFN-β pretreatment was more effective in protecting against subsequent WNV infection in wt cells than TRIM6-KO, indicating that TRIM6 contributes to the establishment of an IFN-induced antiviral response against WNV. Using next-generation sequencing, we identified VAMP8 as a potential factor involved in this TRIM6-mediated antiviral response. VAMP8 knockdown resulted in reduced JAK1 and STAT1 phosphorylation and impaired induction of several interferon-stimulated genes (ISGs) following WNV infection or IFN-β treatment. Furthermore, VAMP8-mediated STAT1 phosphorylation required the presence of TRIM6. Therefore, the VAMP8 protein is a novel regulator of IFN-I signaling, and its expression and function are dependent on TRIM6 activity. Overall, these results provide evidence that TRIM6 contributes to the antiviral response against WNV and identify VAMP8 as a novel regulator of the IFN-I system.IMPORTANCE WNV is a mosquito-borne flavivirus that poses a threat to human health across large discontinuous areas throughout the world. Infection with WNV results in febrile illness, which can progress to severe neurological disease. Currently, there are no approved treatment options to control WNV infection. Understanding the cellular immune responses that regulate viral replication is important in diversifying the resources available to control WNV. Here, we show that the elimination of TRIM6 in human cells results in an increase in WNV replication and alters the expression and function of other components of the IFN-I pathway through VAMP8. Dissecting the interactions between WNV and host defenses both informs basic molecular virology and promotes the development of host- and virus-targeted antiviral strategies.
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Affiliation(s)
- Sarah van Tol
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Colm Atkins
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Preeti Bharaj
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Kendra N Johnson
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Adam Hage
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Alexander N Freiberg
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, USA
| | - Ricardo Rajsbaum
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
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10
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Corona AK, Saulsbery HM, Corona Velazquez AF, Jackson WT. Enteroviruses Remodel Autophagic Trafficking through Regulation of Host SNARE Proteins to Promote Virus Replication and Cell Exit. Cell Rep 2019; 22:3304-3314. [PMID: 29562185 DOI: 10.1016/j.celrep.2018.03.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 12/15/2017] [Accepted: 02/28/2018] [Indexed: 11/30/2022] Open
Abstract
Enterovirus D68 (EV-D68) is a medically important respiratory plus-strand RNA virus of children that has been linked to acute flaccid myelitis. We have determined that EV-D68 induces autophagic signaling and membrane formation. Autophagy, a homeostatic degradative process that breaks down protein aggregates and damaged organelles, promotes replication of multiple plus-strand viruses. Induction of autophagic signals promotes EV-D68 replication, but the virus inhibits the downstream degradative steps of autophagy in multiple ways. EV-D68 proteases cleave a major autophagic cargo adaptor and the autophagic SNARE SNAP29, which reportedly regulates fusion between autophagosome to amphisome/autolysosome. Although the virus inhibits autophagic degradation, SNAP29 promotes virus replication early in infection. An orphan SNARE, SNAP47, is shown to have a previously unknown role in autophagy, and SNAP47 promotes the replication of EV-D68. Our study illuminates a mechanism for subversion of autophagic flux and redirection of the autophagic membranes to benefit EV-D68 replication.
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Affiliation(s)
- Abigail K Corona
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore Avenue, Baltimore, MD 21201, USA
| | - Holly M Saulsbery
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore Avenue, Baltimore, MD 21201, USA
| | - Angel F Corona Velazquez
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore Avenue, Baltimore, MD 21201, USA
| | - William T Jackson
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore Avenue, Baltimore, MD 21201, USA.
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Röhl J, West ZE, Rudolph M, Zaharia A, Van Lonkhuyzen D, Hickey DK, Semmler ABT, Murray RZ. Invasion by activated macrophages requires delivery of nascent membrane-type-1 matrix metalloproteinase through late endosomes/lysosomes to the cell surface. Traffic 2019; 20:661-673. [PMID: 31297933 DOI: 10.1111/tra.12675] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 07/08/2019] [Accepted: 07/09/2019] [Indexed: 12/17/2022]
Abstract
Macrophage migration into injured or infected tissue is a key aspect in the pathophysiology of many diseases where inflammation is a driving factor. Membrane-type-1 matrix metalloproteinase (MT1-MMP) cleaves extracellular matrix components to facilitate invasion. Here we show that, unlike the constitutive MT1-MMP surface recycling seen in cancer cells, unactivated macrophages express low levels of MT1-MMP. Upon lipopolysaccharide (LPS) activation, MT1-MMP synthesis dramatically increases 10-fold at the surface by 15 hours. MT1-MMP is trafficked from the Golgi complex to the surface via late endosomes/lysosomes in a pathway regulated by the late endosome/lysosome R-SNAREs VAMP7 and VAMP8. These form two separate complexes with the surface Q-SNARE complex Stx4/SNAP23 to regulate MT1-MMP delivery to the plasma membrane. Loss of either one of these SNAREs leads to a reduction in surface MT1-MMP, gelatinase activity and reduced invasion. Thus, inhibiting MT1-MMP transport through this pathway could reduce macrophage migration and the resulting inflammation.
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Affiliation(s)
- Joan Röhl
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Zoe E West
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Maren Rudolph
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Andreea Zaharia
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Derek Van Lonkhuyzen
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Danica K Hickey
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Annalese B T Semmler
- Institute of Health and Biomedical Innovation, School of Clinical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Rachael Z Murray
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
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Llobet D, Vallvé C, Tirado I, Vilalta N, Murillo J, Cuevas B, Román L, Carrasco M, Oliver A, Mateo J, Fontcuberta J, Souto JC. VAMP8 and serotonin transporter levels are associated with venous thrombosis risk in a Spanish female population. Results from the RETROVE Project. Thromb Res 2019; 181:99-105. [PMID: 31382081 DOI: 10.1016/j.thromres.2019.07.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/19/2019] [Accepted: 07/25/2019] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Platelet hyper-reactivity has been associated with thrombosis and high levels of human vesicle-associated membrane protein 8 (VAMP8) and serotonin transporter (SERT). Two polymorphisms (rs1010 of VAMP8 gene and in SERT gene (SLC6A4)) are associated with arterial thrombosis. AIM To determine if levels of serotonin, SERT and/or VAMP8 and these polymorphisms are associated with the risk of venous thrombosis. MATERIAL AND METHODS A total of 324 individuals were included in the RETROVE Study (Riesgo de Enfermedad TROmboembólica VEnosa). VAMP8, SERT and serotonin were determined by ELISA; polymorphisms of SLC6A4 and VAMP8 by polymerase chain reaction (PCR) and real time PCR. The venous thrombotic risk was calculated by a logistic regression method to estimate the crude and adjusted OR (adjusted for sex, age, body mass index and venous thrombosis risk co-factors). RESULTS Statistically significant high levels of VAMP8 and SERT were found in patients, but not in controls. In contrast, serotonin showed lower levels in patients than in controls. When individuals were studied by gender, only women exhibited a statistically significant difference: the OR for VAMP8 was 3.25 (1.61-6.56 95% CI). The adjusted OR did not change. The OR for SERT was 2.76 (1.36-5.60 95% CI), the adjusted OR was maintained also. For serotonin with OR of 2.62 (1.40-4.92 95% CI), the adjusted OR was not significant. In contrast males did not show significant differences. No statistically differences between patients and controls were found for both polymorphisms. CONCLUSIONS VAMP8 and SERT levels are associated with venous thrombosis in a female Spanish population.
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Affiliation(s)
- Dolors Llobet
- Unitat de Hemostàsia i Trombosi, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
| | - Cristina Vallvé
- Unitat de Hemostàsia i Trombosi, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Isabel Tirado
- Unitat de Hemostàsia i Trombosi, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Noèlia Vilalta
- Unitat de Hemostàsia i Trombosi, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Joaquín Murillo
- Unitat de Hemostàsia i Trombosi, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Biel Cuevas
- Unitat de Hemostàsia i Trombosi, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Lidia Román
- Unitat de Hemostàsia i Trombosi, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Marina Carrasco
- Unitat de Hemostàsia i Trombosi, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Artur Oliver
- Haematology Department, Fundació Puigvert, Barcelona, Spain
| | - Jose Mateo
- Unitat de Hemostàsia i Trombosi, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Jordi Fontcuberta
- Unitat de Hemostàsia i Trombosi, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Juan Carlos Souto
- Unitat de Hemostàsia i Trombosi, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
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Lin Y, Wu C, Wang X, Liu S, Kemper T, Li F, Squire A, Zhu Y, Zhang J, Chen X, Lu M. Synaptosomal‐associated protein 29 is required for the autophagic degradation of hepatitis B virus. FASEB J 2019; 33:6023-6034. [PMID: 30742775 DOI: 10.1096/fj.201801995rr] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Yong Lin
- Institute of VirologyUniversity Hospital EssenUniversity of Duisburg‐Essen Essen Germany
| | - Chunchen Wu
- State Key Laboratory of VirologyWuhan Institute of VirologyChinese Academy of Sciences Wuhan China
| | - Xueyu Wang
- Institute of VirologyUniversity Hospital EssenUniversity of Duisburg‐Essen Essen Germany
| | - Shi Liu
- Institute of VirologyUniversity Hospital EssenUniversity of Duisburg‐Essen Essen Germany
- State Key Laboratory of VirologyCollege of Life SciencesWuhan University Wuhan China
| | - Thekla Kemper
- Institute of VirologyUniversity Hospital EssenUniversity of Duisburg‐Essen Essen Germany
| | - Fahong Li
- Institute of VirologyUniversity Hospital EssenUniversity of Duisburg‐Essen Essen Germany
- Department of Infectious DiseasesHuashan HospitalFudan University Shanghai China
| | - Anthony Squire
- Institute for Experimental Immunology and ImagingUniversity Hospital EssenUniversity of Duisburg‐Essen Essen Germany
| | - Ying Zhu
- State Key Laboratory of VirologyCollege of Life SciencesWuhan University Wuhan China
| | - Jiming Zhang
- Department of Infectious DiseasesHuashan HospitalFudan University Shanghai China
| | - Xinwen Chen
- State Key Laboratory of VirologyWuhan Institute of VirologyChinese Academy of Sciences Wuhan China
| | - Mengji Lu
- Institute of VirologyUniversity Hospital EssenUniversity of Duisburg‐Essen Essen Germany
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Wang YS, Tzeng HT, Tsai CH, Cheng HC, Lai WW, Liu HS, Wang YC. VAMP8, a vesicle-SNARE required for RAB37-mediated exocytosis, possesses a tumor metastasis suppressor function. Cancer Lett 2018; 437:79-88. [PMID: 30165196 DOI: 10.1016/j.canlet.2018.08.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 08/20/2018] [Indexed: 12/23/2022]
Abstract
We previously identified a metastasis suppressor RAB37 small GTPase that regulated exocytosis of tissue inhibitor of metalloproteinases 1 (TIMP1) to suppress lung cancer metastasis. Here, we show that vesicle-associated membrane protein 8 (VAMP8), a v-SNARE (vesicle soluble N-ethylmaleimide-sensitive factor activating protein receptor), interacts with RAB37 and drives the secretion of TIMP1 to inhibit tumor metastases. Confocal and total internal reflection fluorescence microscopic images demonstrated that VAMP8 co-localized with RAB37 and facilitated trafficking of RAB37-TIMP1 vesicles. Reconstitution experiments using tail-vein injection and lung-to-lung metastasis in mice showed that VAMP8 was essential for RAB37-regulated vesicle trafficking of TIMP1 to suppress cancer metastasis. Lung cancer patients with low VAMP8 showed distant metastasis, poor overall survival and progression-free survival. Importantly, multivariate Cox regression analysis indicated that patients with low VAMP8/low RAB37 expression profile showed significantly high risk of death (hazard ratio = 3.42, P < 0.001) even after adjusting for tumor metastasis parameter. Our findings reveal that VAMP8 is a novel v-SNARE crucial for RAB37-mediated exocytic transport of TIMP1 to suppress lung tumor metastasis. VAMP8 possesses a tumor metastasis suppressor function with a prognostic value in lung cancer.
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Abstract
Picornaviruses, one of the major causes of human diseases ranging from the common cold to acute flaccid paralysis, have a short cytosolic lifecycle that, in cultured cells, ends in cell lysis. For years, the prevailing model was that these viruses exit from cells exclusively through cell lysis. However, over the last several years it has become apparent that for some picornaviruses, a macroautophagy/autophagy-related pathway can result in release of virus particles wrapped in a membrane containing autophagic markers. It has been proposed that this enveloped release predominates within hosts, allowing cell-to-cell movement of virus while minimizing exposure to the immune system. One reason that picornaviruses induce the autophagy pathway is to provide membrane scaffolds for RNA replication complexes. Perhaps more importantly, acidified autophagosomes (known as amphisomes) provide havens for maturation of new viral particles into infectious viruses. In back-to-back papers recently published in Cell Reports, our labs investigated a basic question: if picornavirus particles are maturing inside amphisomes, then how are they avoiding the typical degradative fate of autophagic cargo and exiting the cell intact?
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Affiliation(s)
- Abigail K Corona
- a Department of Microbiology and Immunology , University of Maryland School of Medicine , Baltimore , MD , USA
| | - Yasir Mohamud
- b Center for Heart Lung Innovation, St. Paul's Hospital and Department of Pathology and Laboratory Medicine , University of British Columbia , Vancouver , BC , Canada
| | - William T Jackson
- a Department of Microbiology and Immunology , University of Maryland School of Medicine , Baltimore , MD , USA
| | - Honglin Luo
- b Center for Heart Lung Innovation, St. Paul's Hospital and Department of Pathology and Laboratory Medicine , University of British Columbia , Vancouver , BC , Canada
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16
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Dodson M, Liu P, Jiang T, Ambrose AJ, Luo G, Rojo de la Vega M, Cholanians AB, Wong PK, Chapman E, Zhang DD. Increased O-GlcNAcylation of SNAP29 Drives Arsenic-Induced Autophagic Dysfunction. Mol Cell Biol 2018; 38. [PMID: 29507186 DOI: 10.1128/MCB.00595-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 02/26/2018] [Indexed: 12/17/2022] Open
Abstract
Environmental exposure to arsenic is linked to adverse health effects, including cancer and diabetes. Pleiotropic cellular effects are observed with arsenic exposure. Previously, we demonstrated that arsenic dysregulated the autophagy pathway at low, environmentally relevant concentrations. Here we show that arsenic blocks autophagy by preventing autophagosome-lysosome fusion. Specifically, arsenic disrupts formation of the STX17-SNAP29-VAMP8 SNARE complex, where SNAP29 mediates vesicle fusion through bridging STX17-containing autophagosomes to VAMP8-bearing lysosomes. Mechanistically, arsenic inhibits SNARE complex formation, at least in part, by enhancing O-GlcNAcylation of SNAP29. Transfection of O-GlcNAcylation-defective, but not wild-type, SNAP29 into clustered regularly interspaced short palindromic repeat (CRISPR)-mediated SNAP29 knockout cells abolishes arsenic-mediated autophagy inhibition. These findings reveal a mechanism by which low levels of arsenic perturb proteostasis through inhibition of SNARE complex formation, providing a possible therapeutic target for disease intervention in the more than 200 million people exposed to unsafe levels of arsenic.
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17
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Dingjan I, Paardekooper LM, Verboogen DRJ, von Mollard GF, Ter Beest M, van den Bogaart G. VAMP8-mediated NOX2 recruitment to endosomes is necessary for antigen release. Eur J Cell Biol 2017; 96:705-714. [PMID: 28688576 PMCID: PMC5641923 DOI: 10.1016/j.ejcb.2017.06.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 06/21/2017] [Accepted: 06/21/2017] [Indexed: 11/24/2022] Open
Abstract
Climbing beans produced more than bush beans for 80% of the farmers. Both bean and maize responded positively to DAP fertilizer in 60% of the farms. Early planting increased fertilizer effects in bean-maize rotations. DAP is more profitable in climbing bean-rotation than in bush bean-maize rotation.
Cross-presentation of foreign antigen in major histocompatibility complex (MHC) class I by dendritic cells (DCs) requires activation of the NADPH-oxidase NOX2 complex. We recently showed that NOX2 is recruited to phagosomes by the SNARE protein VAMP8 where NOX2-produced reactive oxygen species (ROS) cause lipid oxidation and membrane disruption, promoting antigen translocation into the cytosol for cross-presentation. In this study, we extend these findings by showing that VAMP8 is also involved in NOX2 trafficking to endosomes. Moreover, we demonstrate in both human and mouse DCs that absence of VAMP8 leads to decreased ROS production, lipid peroxidation and antigen translocation, and that this impairs cross-presentation. In contrast, knockdown of VAMP8 did not affect recruitment of MHC class I and the transporter associated with antigen processing 1 (TAP1) to phagosomes, although surface levels of MHC class I were reduced. Thus, in addition to a secretory role, VAMP8-mediates trafficking of NOX2 to endosomes and phagosomes and this promotes induction of cytolytic T cell immune responses.
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Affiliation(s)
- Ilse Dingjan
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | - Laurent M Paardekooper
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | - Daniëlle R J Verboogen
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | | | - Martin Ter Beest
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | - Geert van den Bogaart
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands.
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Hubert V, Peschel A, Langer B, Gröger M, Rees A, Kain R. LAMP-2 is required for incorporating syntaxin-17 into autophagosomes and for their fusion with lysosomes. Biol Open 2016; 5:1516-1529. [PMID: 27628032 PMCID: PMC5087675 DOI: 10.1242/bio.018648] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Autophagy is an evolutionarily conserved process used for removing surplus and damaged proteins and organelles from the cytoplasm. The unwanted material is incorporated into autophagosomes that eventually fuse with lysosomes, leading to the degradation of their cargo. The fusion event is mediated by the interaction between the Qa-SNARE syntaxin-17 (STX17) on autophagosomes and the R-SNARE VAMP8 on lysosomes. Cells deficient in lysosome membrane-associated protein-2 (LAMP-2) have increased numbers of autophagosomes but the underlying mechanism is poorly understood. By transfecting LAMP-2-deficient and LAMP-1/2-double-deficient mouse embryonic fibroblasts (MEFs) with a tandem fluorescent-tagged LC3 we observed a failure of fusion between the autophagosomes and the lysosomes that could be rescued by complementation with LAMP-2A. Although we observed no change in expression and localization of VAMP8, its interacting partner STX17 was absent from autophagosomes of LAMP-2-deficient cells. Thus, LAMP-2 is essential for STX17 expression by the autophagosomes and this absence is sufficient to explain their failure to fuse with lysosomes. The results have clear implications for situations associated with a reduction of LAMP-2 expression. Summary: LAMP-2 is required for autophagosome-lysosome fusion. Its absence does not affect the lysosomal SNARE VAMP8 while its interacting partner STX17 is absent from the autophagosomes providing a molecular explanation for this fusion failure.
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Affiliation(s)
- Virginie Hubert
- Clinical Institute of Pathology, Medical University of Vienna, Vienna 1090, Austria
| | - Andrea Peschel
- Clinical Institute of Pathology, Medical University of Vienna, Vienna 1090, Austria
| | - Brigitte Langer
- Clinical Institute of Pathology, Medical University of Vienna, Vienna 1090, Austria
| | - Marion Gröger
- Core Facilities, Medical University of Vienna, Vienna 1090, Austria
| | - Andrew Rees
- Clinical Institute of Pathology, Medical University of Vienna, Vienna 1090, Austria
| | - Renate Kain
- Clinical Institute of Pathology, Medical University of Vienna, Vienna 1090, Austria
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Malmersjö S, Di Palma S, Diao J, Lai Y, Pfuetzner RA, Wang AL, McMahon MA, Hayer A, Porteus M, Bodenmiller B, Brunger AT, Meyer T. Phosphorylation of residues inside the SNARE complex suppresses secretory vesicle fusion. EMBO J 2016; 35:1810-21. [PMID: 27402227 PMCID: PMC5010044 DOI: 10.15252/embj.201694071] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 06/09/2016] [Indexed: 12/22/2022] Open
Abstract
Membrane fusion is essential for eukaryotic life, requiring SNARE proteins to zipper up in an α‐helical bundle to pull two membranes together. Here, we show that vesicle fusion can be suppressed by phosphorylation of core conserved residues inside the SNARE domain. We took a proteomics approach using a PKCB knockout mast cell model and found that the key mast cell secretory protein VAMP8 becomes phosphorylated by PKC at multiple residues in the SNARE domain. Our data suggest that VAMP8 phosphorylation reduces vesicle fusion in vitro and suppresses secretion in living cells, allowing vesicles to dock but preventing fusion with the plasma membrane. Markedly, we show that the phosphorylation motif is absent in all eukaryotic neuronal VAMPs, but present in all other VAMPs. Thus, phosphorylation of SNARE domains is a general mechanism to restrict how much cells secrete, opening the door for new therapeutic strategies for suppression of secretion.
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Affiliation(s)
- Seth Malmersjö
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Serena Di Palma
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland Functional Genomics Center Zurich, ETH Zurich/University of Zurich, Zurich, Switzerland
| | - Jiajie Diao
- Departments of Molecular and Cellular Physiology, Neurology and Neurological Sciences, Photon Science, and Structural Biology, Stanford University, Stanford, CA, USA Howard Hughes Medical Institute, Stanford, CA, USA
| | - Ying Lai
- Departments of Molecular and Cellular Physiology, Neurology and Neurological Sciences, Photon Science, and Structural Biology, Stanford University, Stanford, CA, USA Howard Hughes Medical Institute, Stanford, CA, USA
| | - Richard A Pfuetzner
- Departments of Molecular and Cellular Physiology, Neurology and Neurological Sciences, Photon Science, and Structural Biology, Stanford University, Stanford, CA, USA Howard Hughes Medical Institute, Stanford, CA, USA
| | - Austin L Wang
- Departments of Molecular and Cellular Physiology, Neurology and Neurological Sciences, Photon Science, and Structural Biology, Stanford University, Stanford, CA, USA Howard Hughes Medical Institute, Stanford, CA, USA
| | - Moira A McMahon
- Department of Pediatrics, Stanford University, Stanford, CA, USA
| | - Arnold Hayer
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Matthew Porteus
- Department of Pediatrics, Stanford University, Stanford, CA, USA
| | - Bernd Bodenmiller
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Axel T Brunger
- Departments of Molecular and Cellular Physiology, Neurology and Neurological Sciences, Photon Science, and Structural Biology, Stanford University, Stanford, CA, USA Howard Hughes Medical Institute, Stanford, CA, USA
| | - Tobias Meyer
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
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Wilson JD, Shelby SA, Holowka D, Baird B. Rab11 Regulates the Mast Cell Exocytic Response. Traffic 2016; 17:1027-41. [PMID: 27288050 DOI: 10.1111/tra.12418] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 06/07/2016] [Accepted: 06/07/2016] [Indexed: 01/30/2023]
Abstract
Stimulated exocytic events provide a means for physiological communication and are a hallmark of the mast cell-mediated allergic response. In mast cells these processes are triggered by antigen crosslinking of IgE bound to its high-affinity receptor, FcϵRI, on the cell surface. Here we use the endosomal v-SNARE VAMP8, and the lysosomal hydrolase β-hexosaminidase (β-Hex), each C-terminally fused to super-ecliptic pHluorin, to monitor stimulated exocytosis. Using these pHluorin-tagged constructs, we monitor stimulated exocytosis by fluorimetry and visualize individual exocytic events with total internal reflection (TIRF) microscopy. Similar to constitutive recycling endosome (RE) trafficking, we find that stimulated RE exocytosis, monitored by VAMP8, is attenuated by expression of dominant negative (S25N) Rab11. Stimulated β-Hex exocytosis is also reduced in the presence of S25N Rab11, suggesting that expression of this mutant broadly impacts exocytosis. Interestingly, pretreatment with inhibitors of actin polymerization, cytochalasin D or latrunculin A, substantially restores both RE and lysosome exocytosis in cells expressing S25N Rab11. Conversely, stabilizing F-actin with jasplakinolide inhibits antigen-stimulated exocytosis but is not additive with S25N Rab11-mediated inhibition, suggesting that these reagents inhibit related processes. Together, our results suggest that Rab11 participates in the regulation necessary for depolymerization of the actin cytoskeleton during stimulated exocytosis in mast cells.
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Affiliation(s)
- Joshua D Wilson
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853-1301, USA
| | - Sarah A Shelby
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853-1301, USA
| | - David Holowka
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853-1301, USA
| | - Barbara Baird
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853-1301, USA
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Bhat R, Bhattacharyya PK, Ratech H. An Immunohistochemical Survey of SNARE Proteins Shows Distinct Patterns of Expression in Hematolymphoid Neoplasia. Am J Clin Pathol 2016; 145:604-16. [PMID: 27247366 DOI: 10.1093/ajcp/aqw022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Five proteins from the soluble N-ethylmaleimide-sensitive factor activating protein receptor (SNARE) complex family were studied in normal hematopoietic cells in bone marrow; normal lymphocytes at different stages of maturation and differentiation in bone marrow, thymus, tonsil, and lymph node; malignant lymphomas; and leukemias. METHODS Sixty-eight reactive and 380 hematopoietic and lymphoid neoplasms were immunohistochemically stained for syntaxin 7 (STX7), vesicle-associated membrane proteins (VAMP2, VAMP7, VAMP8), and synaptosomal-associated protein 23 (SNAP23). RESULTS STX7 has potential for being a useful marker for distinguishing between normal B precursors (hematogones) vs B lymphoblasts, as well as between the "popcorn" cells of nodular lymphocyte-predominant Hodgkin lymphoma vs the Reed-Sternberg cells of classic Hodgkin lymphoma or the B cells of T-cell, histiocyte-rich B-cell lymphoma. VAMP2 is uniquely expressed by both reactive and malignant plasma cells, in contrast to B-cell non-Hodgkin lymphoma. There is differential expression of SNARE proteins in normal and neoplastic lymphoid tissue depending on lymphocyte maturation stage. CONCLUSIONS Differential SNARE protein expression in the lymphoid system may have potential use in diagnosis and may offer clues to lymphoma biology. VAMP2 is a promising new plasma cell marker.
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Affiliation(s)
- Rekha Bhat
- From the Department of Pathology, Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY
| | | | - Howard Ratech
- From the Department of Pathology, Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY
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Renard HF, Garcia-Castillo MD, Chambon V, Lamaze C, Johannes L. Shiga toxin stimulates clathrin-independent endocytosis of the VAMP2, VAMP3 and VAMP8 SNARE proteins. J Cell Sci 2015; 128:2891-902. [PMID: 26071526 DOI: 10.1242/jcs.171116] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 06/08/2015] [Indexed: 01/08/2023] Open
Abstract
Endocytosis is an essential cellular process that is often hijacked by pathogens and pathogenic products. Endocytic processes can be classified into two broad categories, those that are dependent on clathrin and those that are not. The SNARE proteins VAMP2, VAMP3 and VAMP8 are internalized in a clathrin-dependent manner. However, the full scope of their endocytic behavior has not yet been elucidated. Here, we found that VAMP2, VAMP3 and VAMP8 are localized on plasma membrane invaginations and very early uptake structures that are induced by the bacterial Shiga toxin, which enters cells by clathrin-independent endocytosis. We show that toxin trafficking into cells and cell intoxication rely on these SNARE proteins. Of note, the cellular uptake of VAMP3 is increased in the presence of Shiga toxin, even when clathrin-dependent endocytosis is blocked. We therefore conclude that VAMP2, VAMP3 and VAMP8 are removed from the plasma membrane by non-clathrin-mediated pathways, in addition to by clathrin-dependent uptake. Moreover, our study identifies these SNARE proteins as the first transmembrane trafficking factors that functionally associate at the plasma membrane with the toxin-driven clathrin-independent invaginations during the uptake process.
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Affiliation(s)
- Henri-François Renard
- Institut Curie - Centre de Recherche, Endocytic Trafficking and Therapeutic Delivery Group, 26 rue d'Ulm, Paris 75248, Cedex 05, France CNRS UMR3666, Paris 75005, France INSERM U1143, Paris 75005, France
| | - Maria Daniela Garcia-Castillo
- Institut Curie - Centre de Recherche, Endocytic Trafficking and Therapeutic Delivery Group, 26 rue d'Ulm, Paris 75248, Cedex 05, France CNRS UMR3666, Paris 75005, France INSERM U1143, Paris 75005, France
| | - Valérie Chambon
- Institut Curie - Centre de Recherche, Endocytic Trafficking and Therapeutic Delivery Group, 26 rue d'Ulm, Paris 75248, Cedex 05, France CNRS UMR3666, Paris 75005, France INSERM U1143, Paris 75005, France
| | - Christophe Lamaze
- CNRS UMR3666, Paris 75005, France INSERM U1143, Paris 75005, France Institut Curie - Centre de Recherche, Membrane Dynamics and Mechanics of Intracellular Signaling Group, 26 rue d'Ulm, Paris 75248, Cedex 05, France
| | - Ludger Johannes
- Institut Curie - Centre de Recherche, Endocytic Trafficking and Therapeutic Delivery Group, 26 rue d'Ulm, Paris 75248, Cedex 05, France CNRS UMR3666, Paris 75005, France INSERM U1143, Paris 75005, France
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Abstract
Autophagy, the process for recycling cytoplasm in the lysosome, depends on membrane trafficking. We previously identified Drosophila Sbf as a Rab21 guanine nucleotide exchange factor (GEF) that acts with Rab21 in endosomal trafficking. Here, we show that Sbf/MTMR13 and Rab21 have conserved functions required for starvation-induced autophagy. Depletion of Sbf/MTMR13 or Rab21 blocked endolysosomal trafficking of VAMP8, a SNARE required for autophagosome-lysosome fusion. We show that starvation induces Sbf/MTMR13 GEF and RAB21 activity, as well as their induced binding to VAMP8 (or closest Drosophila homolog, Vamp7). MTMR13 is required for RAB21 activation, VAMP8 interaction and VAMP8 endolysosomal trafficking, defining a novel GEF-Rab-effector pathway. These results identify starvation-responsive endosomal regulators and trafficking that tunes membrane demands with changing autophagy status.
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Affiliation(s)
- Steve Jean
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Sarah Cox
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Sonya Nassari
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Amy A Kiger
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
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Chen Y, Meng D, Wang H, Sun R, Wang D, Wang S, Fan J, Zhao Y, Wang J, Yang S, Huai C, Song X, Qin R, Xu T, Yun D, Hu L, Yang J, Zhang X, Chen H, Chen J, Chen H, Lu D. VAMP8 facilitates cellular proliferation and temozolomide resistance in human glioma cells. Neuro Oncol 2014; 17:407-18. [PMID: 25209430 DOI: 10.1093/neuonc/nou219] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 07/20/2014] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Malignant glioma is a common and lethal primary brain tumor in adults. Here we identified a novel oncoprotein, vesicle-associated membrane protein 8 (VAMP8), and investigated its roles in tumorigenisis and chemoresistance in glioma. METHODS The expression of gene and protein were determined by quantitative PCR and Western blot, respectively. Histological analysis of 282 glioma samples and 12 normal controls was performed by Pearson's chi-squared test. Survival analysis was performed using the log-rank test and Cox proportional hazards regression. Cell proliferation and cytotoxicity assay were conducted using Cell Counting Kit-8. Autophagy was detected by confocal microscopy and Western blot. RESULTS VAMP8 was significantly overexpressed in human glioma specimens and could become a potential novel prognostic and treatment-predictive marker for glioma patients. Overexpression of VAMP8 promoted cell proliferation in vitro and in vivo, whereas knockdown of VAMP8 attenuated glioma growth by arresting cell cycle in the G0/G1 phase. Moreover, VAMP8 contributed to temozolomide (TMZ) resistance by elevating the expression levels of autophagy proteins and the number of autophagosomes. Further inhibition of autophagy via siRNA-mediated knockdown of autophagy-related gene 5 (ATG5) or syntaxin 17 (STX17) reversed TMZ resistance in VAMP8-overexpressing cells, while silencing of VAMP8 impaired the autophagic flux and alleviated TMZ resistance in glioma cells. CONCLUSION Our findings identified VAMP8 as a novel oncogene by promoting cell proliferation and therapeutic resistance in glioma. Targeting VAMP8 may serve as a potential therapeutic regimen for the treatment of glioma.
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Affiliation(s)
- Yuanyuan Chen
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Delong Meng
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Huibo Wang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Ruochuan Sun
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Dongrui Wang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Shuai Wang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Jiajun Fan
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Yingjie Zhao
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Jingkun Wang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Song Yang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Cong Huai
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Xiao Song
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Rong Qin
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Tao Xu
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Dapeng Yun
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Lingna Hu
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Jingmin Yang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Xiaotian Zhang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Haoming Chen
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Juxiang Chen
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Hongyan Chen
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
| | - Daru Lu
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Shanghai, China (Y.C., D.M., D.W., Y.Z., J.W., C.H., X.S., D.Y., L.H., J.Y., H.C., H.C., D.L.); Department of Biosynthesis, School of Pharmacy, Fudan University, Shanghai, China (J.F.); Department of Neurosurgery, (H.W.); Department of Hematology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China (S.W.); Eighth Department of General Surgery and Department of Pathology, First Affiliated Hospital of Anhui Medical University, Hefei, China (R.S., S.Y.); Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas (X.Z.); Neurosurgery Research Institution of Shanghai, Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai, China (R.Q., T.X., J.C.)
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Jun KR, Ullmann R, Khan S, Layman LC, Kim HG. Interstitial microduplication at 2p11.2 in a patient with syndromic intellectual disability: 30-year follow-up. Mol Cytogenet 2014; 7:52. [PMID: 25295072 PMCID: PMC4188067 DOI: 10.1186/1755-8166-7-52] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 06/20/2014] [Indexed: 12/15/2022] Open
Abstract
Background Copy number variations at 2p11.2 have been rare and to our knowledge, no abnormal phenotype with an interstitial 2p11.2 duplication has yet been reported. Here we report the first case with syndromic intellectual disability associated with microduplication at 2p11.2. Results We revisited a white female subject with a chromosome translocation, t(8;10)(p23;q23)mat and a 10q telomeric deletion suspected by G-banding 30 years ago. This female with severe intellectual disability, no speech, facial dysmorphism, intractable epilepsy, recurrent infection, and skeletal abnormalities has been observed from the birth until her death. The karyotype analysis reconfirmed the previously reported chromosome translocation with a revision as 46,XX,t(8;10)(p23.3;q23.2)mat by adding more detail in chromosomal sub-bands. The array comparative genomic hybridization, however, did not detect the 10q terminal deletion originally reported, but instead, revealed a 390 kb duplication at 2p11.2; 46,XX,t(8;10)(p23.3;q23.2)mat.arr[hg 19] 2p11.2(85469151x2,85474356-85864257x3,85868355x2). This duplication region was confirmed by real-time quantitative PCR and real-time reverse transcriptase quantitative PCR. Conclusions We suggest three positional candidate genes for intellectual disability and recurrent infection based upon gene function and data from real-time reverse transcriptase quantitative PCR—VAMP8 and RNF181 for intellectual disability and CAPG for recurrent infection.
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Affiliation(s)
- Kyung Ran Jun
- Department of Laboratory Medicine, Inje University Haeundae Paik Hospital, Busan, South Korea
| | - Reinhard Ullmann
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Saadullah Khan
- Department of Biotechnology & Genetic engineering, Kohat University of Science & Technology (KUST), Kohat, Khyber Pakhtunkhwa, Pakistan
| | - Lawrence C Layman
- Section of Reproductive Endocrinology, Infertility & Genetics, Department of Obstetrics and Gynecology, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Georgia Regents University, 1120 15th Street, Augusta, Georgia ; Neuroscience Program, Medical College of Georgia, Georgia Regents University, Augusta, Georgia
| | - Hyung-Goo Kim
- Section of Reproductive Endocrinology, Infertility & Genetics, Department of Obstetrics and Gynecology, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Georgia Regents University, 1120 15th Street, Augusta, Georgia
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Wesolowski J, Paumet F. Escherichia coli exposure inhibits exocytic SNARE-mediated membrane fusion in mast cells. Traffic 2014; 15:516-30. [PMID: 24494924 DOI: 10.1111/tra.12159] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 01/24/2014] [Accepted: 02/04/2014] [Indexed: 12/11/2022]
Abstract
Mast cells orchestrate the allergic response through the release of proinflammatory mediators, which is driven by the fusion of cytoplasmic secretory granules with the plasma membrane. During this process, SNARE proteins including Syntaxin4, SNAP23 and VAMP8 play a key role. Following stimulation, the kinase IKKβ interacts with and phosphorylates the t-SNARE SNAP23. Phosphorylated SNAP23 then associates with Syntaxin4 and the v-SNARE VAMP8 to form a ternary SNARE complex, which drives membrane fusion and mediator release. Interestingly, mast cell degranulation is impaired following exposure to bacteria such as Escherichia coli. However, the molecular mechanism(s) by which this occurs is unknown. Here, we show that E. coli exposure rapidly and additively inhibits degranulation in the RBL-2H3 rat mast cell line. Following co-culture with E. coli, the interaction between IKKβ and SNAP23 is disrupted, resulting in the hypophosphorylation of SNAP23. Subsequent formation of the ternary SNARE complex between SNAP23, Syntaxin4 and VAMP8 is strongly reduced. Collectively, these results demonstrate that E. coli exposure inhibits the formation of VAMP8-containing exocytic SNARE complexes and thus the release of VAMP8-dependent granules by interfering with SNAP23 phosphorylation.
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Affiliation(s)
- Jordan Wesolowski
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA, USA
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Hegedűs K, Takáts S, Kovács AL, Juhász G. Evolutionarily conserved role and physiological relevance of a STX17/Syx17 (syntaxin 17)-containing SNARE complex in autophagosome fusion with endosomes and lysosomes. Autophagy 2013; 9:1642-6. [PMID: 24113031 DOI: 10.4161/auto.25684] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Phagophores engulf cytoplasmic material and give rise to autophagosomes, double-membrane vesicles mediating cargo transport to lysosomes for degradation. The regulation of autophagosome fusion with endosomes and lysosomes during autophagy has remained poorly characterized. Two recent papers conclude that STX17/syntaxin 17 (Syx17 in Drosophila) has an evolutionarily conserved role in autophagosome fusion with endosomes and lysosomes, acting in one SNARE complex with SNAP29 (ubisnap in Drosophila) and the endosomal/lysosomal VAMP8 (CG1599/Vamp7 in Drosophila). Surprisingly, a third report suggests that STX17 might also contribute to proper phagophore assembly. Although several experiments presented in the two human cell culture studies yielded controversial results, the essential role of STX17 in autophagic flux is now firmly established, both in cultured cells and in an animal model. Based on these data, we propose that genetic inhibition of STX17/Syx17 may be a more specific tool in autophagic flux experiments than currently used drug treatments, which impair all lysosomal degradation routes and also inactivate MTOR (mechanistic target of rapamycin), a major negative regulator of autophagy. Finally, the neuronal dysfunction and locomotion defects observed in Syx17 mutant animals point to the possible contribution of defective autophagosome clearance to various human diseases.
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Affiliation(s)
- Krisztina Hegedűs
- Department of Anatomy, Cell and Developmental Biology; Eötvös Loránd University; Budapest, Hungary
| | - Szabolcs Takáts
- Department of Anatomy, Cell and Developmental Biology; Eötvös Loránd University; Budapest, Hungary
| | - Attila L Kovács
- Department of Anatomy, Cell and Developmental Biology; Eötvös Loránd University; Budapest, Hungary
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology; Eötvös Loránd University; Budapest, Hungary
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Schmidt EM, Schmid E, Münzer P, Hermann A, Eyrich AK, Russo A, Walker B, Gu S, vom Hagen JM, Faggio C, Schaller M, Föller M, Schöls L, Gawaz M, Borst O, Storch A, Stournaras C, Lang F. Chorein sensitivity of cytoskeletal organization and degranulation of platelets. FASEB J 2013; 27:2799-806. [PMID: 23568775 DOI: 10.1096/fj.13-229286] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Chorea-acanthocytosis (ChAc), a lethal disease caused by defective chorein, is characterized by neurodegeneration and erythrocyte acanthocytosis. The functional significance of chorein in other cell types remained ill-defined. The present study revealed chorein expression in blood platelets. As compared to platelets from healthy volunteers, platelets from patients with ChAc displayed a 47% increased globular/filamentous actin ratio, indicating actin depolymerization. Moreover, phosphoinositide-3-kinase subunit p85 phosphorylation, p21 protein-activated kinase (PAK1) phosphorylation, as well as vesicle-associated membrane protein 8 (VAMP8) expression were significantly reduced in platelets from patients with ChAc (by 17, 22, and 39%, respectively) and in megakaryocytic (MEG-01) cells following chorein silencing (by 16, 54, and 11%, respectively). Activation-induced platelet secretion from dense granules (ATP release) and α granules (P-selectin exposure) were significantly less (by 55% after stimulation with 1 μg/ml CRP and by 33% after stimulation with 5 μM TRAP, respectively) in ChAc platelets than in control platelets. Furthermore, platelet aggregation following stimulation with different platelet agonists was significantly impaired. These observations reveal a completely novel function of chorein, i.e., regulation of secretion and aggregation of blood platelets.
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Affiliation(s)
- Eva-Maria Schmidt
- Department of Physiology, University of Tübingen, Gmelinstrasse 5, 72076 Tübingen, Germany
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Furuta N, Amano A. Cellular machinery to fuse antimicrobial autophagosome with lysosome. Commun Integr Biol 2011; 3:385-7. [PMID: 20798834 DOI: 10.4161/cib.3.4.12030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 04/12/2010] [Indexed: 11/19/2022] Open
Abstract
Autophagy is an intracellular bulk degradation/recycling system that turns over cellular constituents and also functions to degrade intracellular foreign microbial invaders by a process termed xenophagy (antimicrobial autophagy). We previously showed that intracellular group A Streptococcus (GAS) organisms are captured by xenophagosomes, then degraded following fusion with lysosomes. Very recently, we analyzed the molecular mechanism underlying xenophagosome/lysosome fusion and found that endocytic soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) were involved. Knockdown of the combinational SNARE proteins Vti1b and VAMP8 with siRNAs disturbed autophagic fusion with lysosomes, and cellular bactericidal efficiency was significantly diminished. Furthermore, knockdown of those SNAREs inhibited the fusion of canonical autophagosomes with lysosomes. In addition, important findings showed that Vti1b is derived from autophagic compartments, whereas VAMP8 originates from lysosomes. Together, these results strongly suggest that SNARE proteins Vti1b and VAMP8 mediate the fusion of antimicrobial and canonical autophagosomes with lysosomes, an essential event for autophagic degradation.
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Affiliation(s)
- Nobumichi Furuta
- Department of Oral Frontier Biology; Graduate School of Dentistry; Osaka University; Suita-Osaka, Japan
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