51
|
Bin NR, Ma K, Tien CW, Wang S, Zhu D, Park S, Turlova E, Sugita K, Shirakawa R, van der Sluijs P, Horiuchi H, Sun HS, Monnier PP, Gaisano HY, Sugita S. C2 Domains of Munc13-4 Are Crucial for Ca 2+-Dependent Degranulation and Cytotoxicity in NK Cells. THE JOURNAL OF IMMUNOLOGY 2018; 201:700-713. [PMID: 29884704 DOI: 10.4049/jimmunol.1800426] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/18/2018] [Indexed: 11/19/2022]
Abstract
In the immune system, degranulation/exocytosis from lymphocytes is crucial for life through facilitating eradication of infected and malignant cells. Dysfunction of the NK cell exocytosis process has been implicated with devastating immune diseases, such as familial hemophagocytic lymphohistiocytosis, yet the underlying molecular mechanisms of such processes have remained elusive. In particular, although the lytic granule exocytosis from NK cells is strictly Ca2+-dependent, the molecular identity of the Ca2+ sensor has yet to be identified. In this article, we show multiple lines of evidence in which point mutations in aspartic acid residues in both C2 domains of human Munc13-4, whose mutation underlies familial hemophagocytic lymphohistiocytosis type 3, diminished exocytosis with dramatically altered Ca2+ sensitivity in both mouse primary NK cells as well as rat mast cell lines. Furthermore, these mutations within the C2 domains severely impaired NK cell cytotoxicity against malignant cells. Total internal reflection fluorescence microscopy analysis revealed that the mutations strikingly altered Ca2+ dependence of fusion pore opening of each single granule and frequency of fusion events. Our results demonstrate that both C2 domains of Munc13-4 play critical roles in Ca2+-dependent exocytosis and cytotoxicity by regulating single-granule membrane fusion dynamics in immune cells.
Collapse
Affiliation(s)
- Na-Ryum Bin
- Division of Fundamental Neurobiology, Krembil Research Institute, University Health Network, Toronto, Ontario M5T 2S8, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Ke Ma
- Division of Fundamental Neurobiology, Krembil Research Institute, University Health Network, Toronto, Ontario M5T 2S8, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Chi-Wei Tien
- Division of Fundamental Neurobiology, Krembil Research Institute, University Health Network, Toronto, Ontario M5T 2S8, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Siyan Wang
- Division of Fundamental Neurobiology, Krembil Research Institute, University Health Network, Toronto, Ontario M5T 2S8, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Dan Zhu
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Department of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Seungmee Park
- Division of Fundamental Neurobiology, Krembil Research Institute, University Health Network, Toronto, Ontario M5T 2S8, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Ekaterina Turlova
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Department of Surgery, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Kyoko Sugita
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, Ontario M5T 2S8, Canada
| | - Ryutaro Shirakawa
- Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan; and
| | - Peter van der Sluijs
- Department of Cell Biology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Hisanori Horiuchi
- Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan; and
| | - Hong-Shuo Sun
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Department of Surgery, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Philippe P Monnier
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, Ontario M5T 2S8, Canada
| | - Herbert Y Gaisano
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Department of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Shuzo Sugita
- Division of Fundamental Neurobiology, Krembil Research Institute, University Health Network, Toronto, Ontario M5T 2S8, Canada; .,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| |
Collapse
|
52
|
MacDougall DD, Lin Z, Chon NL, Jackman SL, Lin H, Knight JD, Anantharam A. The high-affinity calcium sensor synaptotagmin-7 serves multiple roles in regulated exocytosis. J Gen Physiol 2018; 150:783-807. [PMID: 29794152 PMCID: PMC5987875 DOI: 10.1085/jgp.201711944] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 05/07/2018] [Indexed: 12/19/2022] Open
Abstract
MacDougall et al. review the structure and function of the calcium sensor synaptotagmin-7 in exocytosis. Synaptotagmin (Syt) proteins comprise a 17-member family, many of which trigger exocytosis in response to calcium. Historically, most studies have focused on the isoform Syt-1, which serves as the primary calcium sensor in synchronous neurotransmitter release. Recently, Syt-7 has become a topic of broad interest because of its extreme calcium sensitivity and diversity of roles in a wide range of cell types. Here, we review the known and emerging roles of Syt-7 in various contexts and stress the importance of its actions. Unique functions of Syt-7 are discussed in light of recent imaging, electrophysiological, and computational studies. Particular emphasis is placed on Syt-7–dependent regulation of synaptic transmission and neuroendocrine cell secretion. Finally, based on biochemical and structural data, we propose a mechanism to link Syt-7’s role in membrane fusion with its role in subsequent fusion pore expansion via strong calcium-dependent phospholipid binding.
Collapse
Affiliation(s)
| | - Zesen Lin
- Department of Pharmacology, University of Michigan, Ann Arbor, MI
| | - Nara L Chon
- Department of Chemistry, University of Colorado, Denver, CO
| | - Skyler L Jackman
- Vollum Institute, Oregon Health & Science University, Portland, OR
| | - Hai Lin
- Department of Chemistry, University of Colorado, Denver, CO
| | | | - Arun Anantharam
- Department of Pharmacology, University of Michigan, Ann Arbor, MI
| |
Collapse
|
53
|
Michelet X, Tuli A, Gan H, Geadas C, Sharma M, Remold HG, Brenner MB. Lysosome-Mediated Plasma Membrane Repair Is Dependent on the Small GTPase Arl8b and Determines Cell Death Type in Mycobacterium tuberculosis Infection. THE JOURNAL OF IMMUNOLOGY 2018; 200:3160-3169. [PMID: 29592961 DOI: 10.4049/jimmunol.1700829] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 02/23/2018] [Indexed: 01/06/2023]
Abstract
Mycobacterium tuberculosis is an extremely successful pathogen, and its success is widely attributed to its ability to manipulate the intracellular environment of macrophages. A central phenomenon of tuberculosis pathology enabling immune evasion is the capacity of virulent M. tuberculosis (H37Rv) to induce macrophage necrosis, which facilitates the escape of the mycobacteria from the macrophage and spread of infection. In contrast, avirulent M. tuberculosis (H37Ra) induces macrophage apoptosis, which permits Ag presentation and activation of adaptive immunity. Previously, we found that H37Rv induces plasma membrane microdisruptions, leading to necrosis in the absence of plasma membrane repair. In contrast, H37Ra permits plasma membrane repair, which changes the host cell death modality to apoptosis, suggesting that membrane repair is critical for sequestering the pathogen in apoptotic vesicles. However, mechanisms of plasma membrane repair induced in response to M. tuberculosis infection remain unknown. Plasma membrane repair is known to induce a Ca2+-mediated signaling, which recruits lysosomes to the area of damaged plasma membrane sites for its resealing. In this study, we found that the small GTPase Arl8b is required for plasma membrane repair by controlling the exocytosis of lysosomes in cell lines and in human primary macrophages. Importantly, we found that the Arl8b secretion pathway is crucial to control the type of cell death of the M. tuberculosis-infected macrophages. Indeed, Arl8b-depleted macrophages infected with avirulent H37Ra undergo necrotic instead of apoptotic cell death. These findings suggest that membrane repair mediated by Arl8b may be an important mechanism distinguishing avirulent from virulent M. tuberculosis-induced necrotic cell death.
Collapse
Affiliation(s)
- Xavier Michelet
- Division of Rheumatology, Immunology and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115;
| | - Amit Tuli
- Division of Rheumatology, Immunology and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115; .,Division of Cell Biology and Immunology, Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh 160036, India; and
| | - Huixian Gan
- Division of Rheumatology, Immunology and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Carolina Geadas
- Division of Rheumatology, Immunology and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Mahak Sharma
- Division of Rheumatology, Immunology and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115.,Department of Biological Sciences, Indian Institute of Science Education and Research, Mohali, Punjab 140306, India
| | - Heinz G Remold
- Division of Rheumatology, Immunology and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Michael B Brenner
- Division of Rheumatology, Immunology and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115;
| |
Collapse
|
54
|
Maxson ME, Naj X, O'Meara TR, Plumb JD, Cowen LE, Grinstein S. Integrin-based diffusion barrier separates membrane domains enabling the formation of microbiostatic frustrated phagosomes. eLife 2018; 7:34798. [PMID: 29553370 PMCID: PMC5897098 DOI: 10.7554/elife.34798] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 03/16/2018] [Indexed: 12/25/2022] Open
Abstract
Candida albicans hyphae can reach enormous lengths, precluding their internalization by phagocytes. Nevertheless, macrophages engulf a portion of the hypha, generating incompletely sealed tubular phagosomes. These frustrated phagosomes are stabilized by a thick cuff of F-actin that polymerizes in response to non-canonical activation of integrins by fungal glycan. Despite their continuity, the surface and invaginating phagosomal membranes retain a strikingly distinct lipid composition. PtdIns(4,5)P2 is present at the plasmalemma but is not detectable in the phagosomal membrane, while PtdIns(3)P and PtdIns(3,4,5)P3 co-exist in the phagosomes yet are absent from the surface membrane. Moreover, endo-lysosomal proteins are present only in the phagosomal membrane. Fluorescence recovery after photobleaching revealed the presence of a diffusion barrier that maintains the identity of the open tubular phagosome separate from the plasmalemma. Formation of this barrier depends on Syk, Pyk2/Fak and formin-dependent actin assembly. Antimicrobial mechanisms can thereby be deployed, limiting the growth of the hyphae.
Collapse
Affiliation(s)
- Michelle E Maxson
- Program in Cell Biology, Hospital for Sick Children, Toronto, Canada
| | - Xenia Naj
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Teresa R O'Meara
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Jonathan D Plumb
- Program in Cell Biology, Hospital for Sick Children, Toronto, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, Canada.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
| |
Collapse
|
55
|
Sun X, Yang Y, Zhong XZ, Cao Q, Zhu XH, Zhu X, Dong XP. A negative feedback regulation of MTORC1 activity by the lysosomal Ca 2+ channel MCOLN1 (mucolipin 1) using a CALM (calmodulin)-dependent mechanism. Autophagy 2018; 14:38-52. [PMID: 29460684 DOI: 10.1080/15548627.2017.1389822] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Macroautophagy/autophagy is an evolutionarily conserved pathway that is required for cellular homeostasis, growth and survival. The lysosome plays an essential role in autophagy regulation. For example, the activity of MTORC1, a master regulator of autophagy, is regulated by nutrients within the lysosome. Starvation inhibits MTORC1 causing autophagy induction. Given that MTORC1 is critical for protein synthesis and cellular homeostasis, a feedback regulatory mechanism must exist to restore MTORC1 during starvation. However, the molecular mechanism underlying this feedback regulation is unclear. In this study, we report that starvation activates the lysosomal Ca2+ release channel MCOLN1 (mucolipin 1) by relieving MTORC1's inhibition of the channel. Activated MCOLN1 in turn facilitates MTORC1 activity that requires CALM (calmodulin). Moreover, both MCOLN1 and CALM are necessary for MTORC1 reactivation during prolonged starvation. Our data suggest that lysosomal Ca2+ signaling is an essential component of the canonical MTORC1-dependent autophagy pathway and MCOLN1 provides a negative feedback regulation of MTORC1 to prevent excessive loss of MTORC1 function during starvation. The feedback regulation may be important for maintaining cellular homeostasis during starvation, as well as many other stressful or disease conditions.
Collapse
Affiliation(s)
- Xue Sun
- a Department of Physiology and Biophysics , Dalhousie University, Sir Charles Tupper Medical Building , Halifax , Nova Scotia, Canada.,d Key Laboratory of Molecular Epigenetics of Ministry of Education , Institute of Cytology and Genetics, Northeast Normal University , Changchun , Jilin , China
| | - Yiming Yang
- a Department of Physiology and Biophysics , Dalhousie University, Sir Charles Tupper Medical Building , Halifax , Nova Scotia, Canada
| | - Xi Zoë Zhong
- a Department of Physiology and Biophysics , Dalhousie University, Sir Charles Tupper Medical Building , Halifax , Nova Scotia, Canada
| | - Qi Cao
- a Department of Physiology and Biophysics , Dalhousie University, Sir Charles Tupper Medical Building , Halifax , Nova Scotia, Canada
| | - Xin-Hong Zhu
- b Institute of Mental Health, Southern Medical University , Guangzhou , China.,c Key Laboratory of Psychiatric Disorders of Guangdong Province , Guangzhou , China
| | - Xiaojuan Zhu
- d Key Laboratory of Molecular Epigenetics of Ministry of Education , Institute of Cytology and Genetics, Northeast Normal University , Changchun , Jilin , China
| | - Xian-Ping Dong
- a Department of Physiology and Biophysics , Dalhousie University, Sir Charles Tupper Medical Building , Halifax , Nova Scotia, Canada
| |
Collapse
|
56
|
Villeneuve J, Bassaganyas L, Lepreux S, Chiritoiu M, Costet P, Ripoche J, Malhotra V, Schekman R. Unconventional secretion of FABP4 by endosomes and secretory lysosomes. J Cell Biol 2017; 217:649-665. [PMID: 29212659 PMCID: PMC5800802 DOI: 10.1083/jcb.201705047] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 10/09/2017] [Accepted: 11/14/2017] [Indexed: 01/30/2023] Open
Abstract
Adipocytes secrete fatty acid binding protein 4, which influences glucose production in hepatocytes and insulin secretion in pancreatic β-cells, but the mechanisms of its secretion are unclear. Villeneuve et al. show that FABP4 is secreted unconventionally through enclosure within endosomes and secretory lysosomes. An appreciation of the functional properties of the cytoplasmic fatty acid binding protein 4 (FABP4) has advanced with the recent demonstration that an extracellular form secreted by adipocytes regulates a wide range of physiological functions. Little, however, is known about the mechanisms that mediate the unconventional secretion of FABP4. Here, we demonstrate that FABP4 secretion is mediated by a membrane-bounded compartment, independent of the conventional endoplasmic reticulum–Golgi secretory pathway. We show that FABP4 secretion is also independent of GRASP proteins, autophagy, and multivesicular bodies but involves enclosure within endosomes and secretory lysosomes. We highlight the physiological significance of this pathway with the demonstration that an increase in plasma levels of FABP4 is inhibited by chloroquine treatment of mice. These findings chart the pathway of FABP4 secretion and provide a potential therapeutic means to control metabolic disorders associated with its dysregulated secretion.
Collapse
Affiliation(s)
- Julien Villeneuve
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA
| | - Laia Bassaganyas
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA.,Institute for Human Genetics, University of California, San Francisco, San Francisco, CA
| | - Sebastien Lepreux
- Institut National de la Santé et de la Recherche Médicale U1026, Université de Bordeaux, Bordeaux, France
| | - Marioara Chiritoiu
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Pierre Costet
- Service des Animaleries, Université de Bordeaux, Bordeaux, France
| | - Jean Ripoche
- Institut National de la Santé et de la Recherche Médicale U1026, Université de Bordeaux, Bordeaux, France
| | - Vivek Malhotra
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain .,Universitat Pompeu Fabra, Barcelona, Spain.,Institutio Catalana de Recerca i Estudis Avancats, Barcelona, Spain
| | - Randy Schekman
- Department of Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA
| |
Collapse
|
57
|
Hatori Y, Inouye S, Akagi R, Seyama T. Local redox environment beneath biological membranes probed by palmitoylated-roGFP. Redox Biol 2017; 14:679-685. [PMID: 29179107 PMCID: PMC5704182 DOI: 10.1016/j.redox.2017.11.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 11/15/2017] [Accepted: 11/16/2017] [Indexed: 12/31/2022] Open
Abstract
Production of reactive oxygen species (ROS) and consequent glutathione oxidation are associated with various physiological processes and diseases, including cell differentiation, senescence, and inflammation. GFP-based redox sensors provide a straight-forward approach to monitor ROS levels and glutathione oxidation within a living cell at the subcellular resolution. We utilized palmitoylated versions of cytosolic glutathione and hydrogen peroxide sensors (Grx1-roGFP2 and roGFP2-Orp1, respectively) and demonstrated a unique redox environment near biological membranes. In HeLa cells, cytosolic glutathione was practically completely reduced (EGSH/GSSG = − 333 mV) and hydrogen peroxide level was under the detectable range. In contrast, the cytoplasmic milieu near membranes of intracellular vesicles exhibited significant glutathione oxidation (EGSH/GSSG > − 256 mV) and relatively high H2O2 production, which was not observed for the plasma membrane. These vesicles colocalized with internalized EGFR, suggesting that H2O2 production and glutathione oxidation are characteristics of cytoplasmic surfaces of the endocytosed vesicles. The results visually illustrate local redox heterogeneity within the cytosol for the first time. Palmitoylated versions of redox sensors were constructed. The sensors successfully visualized local redox environment near membranes. The cytosol is oxidative near endocytosed vesicles containing EGFR.
Collapse
Affiliation(s)
- Yuta Hatori
- Department of Pharmacy, Yasuda Women's University, Hiroshima, Japan.
| | - Sachiye Inouye
- Department of Pharmacy, Yasuda Women's University, Hiroshima, Japan
| | - Reiko Akagi
- Department of Pharmacy, Yasuda Women's University, Hiroshima, Japan
| | - Toshio Seyama
- Department of Pharmacy, Yasuda Women's University, Hiroshima, Japan
| |
Collapse
|
58
|
Daniotti JL, Pedro MP, Valdez Taubas J. The role of S-acylation in protein trafficking. Traffic 2017; 18:699-710. [DOI: 10.1111/tra.12510] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 08/16/2017] [Accepted: 08/20/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Jose L. Daniotti
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET; Universidad Nacional de Córdoba; Córdoba Argentina
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas; Universidad Nacional de Córdoba; Córdoba Argentina
| | - Maria P. Pedro
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET; Universidad Nacional de Córdoba; Córdoba Argentina
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas; Universidad Nacional de Córdoba; Córdoba Argentina
| | - Javier Valdez Taubas
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET; Universidad Nacional de Córdoba; Córdoba Argentina
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas; Universidad Nacional de Córdoba; Córdoba Argentina
| |
Collapse
|
59
|
Mutant Huntingtin Is Secreted via a Late Endosomal/Lysosomal Unconventional Secretory Pathway. J Neurosci 2017; 37:9000-9012. [PMID: 28821645 DOI: 10.1523/jneurosci.0118-17.2017] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 06/26/2017] [Accepted: 08/09/2017] [Indexed: 12/22/2022] Open
Abstract
Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder caused by the expansion of a CAG triplet in the gene encoding for huntingtin (Htt). The resulting mutant protein (mHtt) with extended polyglutamine (polyQ) sequence at the N terminus leads to neuronal degeneration both in a cell-autonomous and a non-cell-autonomous manner. Recent studies identified mHtt in the extracellular environment and suggested that its spreading contributes to toxicity, but the mechanism of mHtt release from the cell of origin remains unknown. In this study, we performed a comprehensive, unbiased analysis of secretory pathways and identified an unconventional lysosomal pathway as an important mechanism for mHtt secretion in mouse neuroblastoma and striatal cell lines, as well as in primary neurons. mHtt secretion was dependent on synaptotagmin 7, a regulator of lysosomal secretion, and inhibited by chemical ablation of late endosomes/lysosomes, suggesting a lysosomal secretory pattern. mHtt was targeted preferentially to the late endosomes/lysosomes compared with wild-type Htt. Importantly, we found that late endosomal/lysosomal targeting and secretion of mHtt could be inhibited efficiently by the phosphatidylinositol 3-kinase and neutral sphingomyelinase chemical inhibitors, Ly294002 and GW4869, respectively. Together, our data suggest a lysosomal mechanism of mHtt secretion and offer potential strategies for pharmacological modulation of its neuronal secretion.SIGNIFICANCE STATEMENT This is the first study examining the mechanism of mutant huntingtin (mHTT) secretion in an unbiased manner. We found that the protein is secreted via a late endosomal/lysosomal unconventional secretory pathway. Moreover, mHtt secretion can be reduced significantly by phosphatidylinositol 3-kinase and neutral sphingomyelinase inhibitors. Understanding and manipulating the secretion of mHtt is important because of its potentially harmful propagation in the brain.
Collapse
|
60
|
Jackman SL, Regehr WG. The Mechanisms and Functions of Synaptic Facilitation. Neuron 2017; 94:447-464. [PMID: 28472650 DOI: 10.1016/j.neuron.2017.02.047] [Citation(s) in RCA: 238] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 02/23/2017] [Accepted: 02/28/2017] [Indexed: 12/22/2022]
Abstract
The ability of the brain to store and process information relies on changing the strength of connections between neurons. Synaptic facilitation is a form of short-term plasticity that enhances synaptic transmission for less than a second. Facilitation is a ubiquitous phenomenon thought to play critical roles in information transfer and neural processing. Yet our understanding of the function of facilitation remains largely theoretical. Here we review proposed roles for facilitation and discuss how recent progress in uncovering the underlying molecular mechanisms could enable experiments that elucidate how facilitation, and short-term plasticity in general, contributes to circuit function and animal behavior.
Collapse
Affiliation(s)
- Skyler L Jackman
- Department of Neurobiology, Harvard Medical School, Boston, MA 02118, USA
| | - Wade G Regehr
- Department of Neurobiology, Harvard Medical School, Boston, MA 02118, USA.
| |
Collapse
|
61
|
Ramadass M, Catz SD. Molecular mechanisms regulating secretory organelles and endosomes in neutrophils and their implications for inflammation. Immunol Rev 2017; 273:249-65. [PMID: 27558339 DOI: 10.1111/imr.12452] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Neutrophils constitute the first line of cellular defense against invading microorganisms and modulate the subsequent innate and adaptive immune responses. In order to execute a rapid and precise response to infections, neutrophils rely on preformed effector molecules stored in a variety of intracellular granules. Neutrophil granules contain microbicidal factors, the membrane-bound components of the respiratory burst oxidase, membrane-bound adhesion molecules, and receptors that facilitate the execution of all neutrophil functions including adhesion, transmigration, phagocytosis, degranulation, and neutrophil extracellular trap formation. The rapid mobilization of intracellular organelles is regulated by vesicular trafficking mechanisms controlled by effector molecules that include small GTPases and their interacting proteins. In this review, we focus on recent discoveries of mechanistic processes that are at center stage of the regulation of neutrophil function, highlighting the discrete and selective pathways controlled by trafficking modulators. In particular, we describe novel pathways controlled by the Rab27a effectors JFC1 and Munc13-4 in the regulation of degranulation, reactive oxygen species and neutrophil extracellular trap production, and endolysosomal signaling. Finally, we discuss the importance of understanding these molecular mechanisms in order to design novel approaches to modulate neutrophil-mediated inflammatory processes in a targeted fashion.
Collapse
Affiliation(s)
- Mahalakshmi Ramadass
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Sergio D Catz
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| |
Collapse
|
62
|
Di Paola S, Scotto-Rosato A, Medina DL. TRPML1: The Ca (2+)retaker of the lysosome. Cell Calcium 2017; 69:112-121. [PMID: 28689729 DOI: 10.1016/j.ceca.2017.06.006] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/16/2017] [Accepted: 06/16/2017] [Indexed: 12/27/2022]
Abstract
Efficient functioning of lysosome is necessary to ensure the correct performance of a variety of intracellular processes such as degradation of cargoes coming from the endocytic and autophagic pathways, recycling of organelles, and signaling mechanisms involved in cellular adaptation to nutrient availability. Mutations in lysosomal genes lead to more than 50 lysosomal storage disorders (LSDs). Among them, mutations in the gene encoding TRPML1 (MCOLN1) cause Mucolipidosis type IV (MLIV), a recessive LSD characterized by neurodegeneration, psychomotor retardation, ophthalmologic defects and achlorhydria. At the cellular level, MLIV patient fibroblasts show enlargement and engulfment of the late endo-lysosomal compartment, autophagy impairment, and accumulation of lipids and glycosaminoglycans. TRPML1 is the most extensively studied member of a small family of genes that also includes TRPML2 and TRPML3, and it has been found to participate in vesicular trafficking, lipid and ion homeostasis, and autophagy. In this review we will provide an update on the latest and more novel findings related to the functions of TRPMLs, with particular focus on the emerging role of TRPML1 and lysosomal calcium signaling in autophagy. Moreover, we will also discuss new potential therapeutic approaches for MLIV and LSDs based on the modulation of TRPML1-mediated signaling.
Collapse
Affiliation(s)
- Simone Di Paola
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli ,NA, Italy
| | - Anna Scotto-Rosato
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli ,NA, Italy
| | - Diego Luis Medina
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli ,NA, Italy.
| |
Collapse
|
63
|
Methods for monitoring Ca 2+ and ion channels in the lysosome. Cell Calcium 2017; 64:20-28. [DOI: 10.1016/j.ceca.2016.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 12/07/2016] [Accepted: 12/07/2016] [Indexed: 12/22/2022]
|
64
|
Encarnação M, Espada L, Escrevente C, Mateus D, Ramalho J, Michelet X, Santarino I, Hsu VW, Brenner MB, Barral DC, Vieira OV. A Rab3a-dependent complex essential for lysosome positioning and plasma membrane repair. J Cell Biol 2017; 213:631-40. [PMID: 27325790 PMCID: PMC4915190 DOI: 10.1083/jcb.201511093] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 05/27/2016] [Indexed: 11/22/2022] Open
Abstract
Encarnação et al. show that Rab3a, together with its newly identified effector NMHC IIA, mediates the positioning of peripheral lysosomes in nonsecretory cells, thereby promoting lysosome exocytosis and plasma membrane repair. Lysosome exocytosis plays a major role in resealing plasma membrane (PM) disruptions. This process involves two sequential steps. First, lysosomes are recruited to the periphery of the cell and then fuse with the damaged PM. However, the trafficking molecular machinery involved in lysosome exocytosis and PM repair (PMR) is poorly understood. We performed a systematic screen of the human Rab family to identify Rabs required for lysosome exocytosis and PMR. Rab3a, which partially localizes to peripheral lysosomes, was one of the most robust hits. Silencing of Rab3a or its effector, synaptotagmin-like protein 4a (Slp4-a), leads to the collapse of lysosomes to the perinuclear region and inhibition of PMR. Importantly, we have also identified a new Rab3 effector, nonmuscle myosin heavy chain IIA, as part of the complex formed by Rab3a and Slp4-a that is responsible for lysosome positioning at the cell periphery and lysosome exocytosis.
Collapse
Affiliation(s)
- Marisa Encarnação
- Centro de Estudos de Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, 1169-056 Lisboa, Portugal
| | - Lília Espada
- Centro de Estudos de Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, 1169-056 Lisboa, Portugal
| | - Cristina Escrevente
- Centro de Estudos de Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, 1169-056 Lisboa, Portugal
| | - Denisa Mateus
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - José Ramalho
- Centro de Estudos de Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, 1169-056 Lisboa, Portugal
| | - Xavier Michelet
- Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Inês Santarino
- Centro de Estudos de Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, 1169-056 Lisboa, Portugal
| | - Victor W Hsu
- Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Michael B Brenner
- Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Duarte C Barral
- Centro de Estudos de Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, 1169-056 Lisboa, Portugal
| | - Otília V Vieira
- Centro de Estudos de Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, 1169-056 Lisboa, Portugal
| |
Collapse
|
65
|
Lv L, Wang Y, Feng W, Hernandez JA, Huang W, Zheng Y, Zhou X, Lv S, Chen Y, Yuan ZG. iTRAQ-based differential proteomic analysis in Mongolian gerbil brains chronically infected with Toxoplasma gondii. J Proteomics 2017; 160:74-83. [DOI: 10.1016/j.jprot.2017.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 02/13/2017] [Accepted: 03/13/2017] [Indexed: 12/12/2022]
|
66
|
Cao Q, Yang Y, Zhong XZ, Dong XP. The lysosomal Ca 2+ release channel TRPML1 regulates lysosome size by activating calmodulin. J Biol Chem 2017; 292:8424-8435. [PMID: 28360104 DOI: 10.1074/jbc.m116.772160] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/29/2017] [Indexed: 01/01/2023] Open
Abstract
Intracellular lysosomal membrane trafficking, including fusion and fission, is crucial for cellular homeostasis and normal cell function. Both fusion and fission of lysosomal membrane are accompanied by lysosomal Ca2+ release. We recently have demonstrated that the lysosomal Ca2+ release channel P2X4 regulates lysosome fusion through a calmodulin (CaM)-dependent mechanism. However, the molecular mechanism underlying lysosome fission remains uncertain. In this study, we report that enlarged lysosomes/vacuoles induced by either vacuolin-1 or P2X4 activation are suppressed by up-regulating the lysosomal Ca2+ release channel transient receptor potential mucolipin 1 (TRPML1) but not the lysosomal Na+ release channel two-pore channel 2 (TPC2). Activation of TRPML1 facilitated the recovery of enlarged lysosomes/vacuoles. Moreover, the effects of TRPML1 on lysosome/vacuole size regulation were eliminated by Ca2+ chelation, suggesting a requirement for TRPML1-mediated Ca2+ release. We further demonstrate that the prototypical Ca2+ sensor CaM is required for the regulation of lysosome/vacuole size by TRPML1, suggesting that TRPML1 may promote lysosome fission by activating CaM. Given that lysosome fission is implicated in both lysosome biogenesis and reformation, our findings suggest that TRPML1 may function as a key lysosomal Ca2+ channel controlling both lysosome biogenesis and reformation.
Collapse
Affiliation(s)
- Qi Cao
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Yiming Yang
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Xi Zoë Zhong
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Xian-Ping Dong
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
| |
Collapse
|
67
|
Borland H, Vilhardt F. Prelysosomal Compartments in the Unconventional Secretion of Amyloidogenic Seeds. Int J Mol Sci 2017; 18:ijms18010227. [PMID: 28124989 PMCID: PMC5297856 DOI: 10.3390/ijms18010227] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/09/2017] [Accepted: 01/16/2017] [Indexed: 12/18/2022] Open
Abstract
A mechanistic link between neuron-to-neuron transmission of secreted amyloid and propagation of protein malconformation cytopathology and disease has recently been uncovered in animal models. An enormous interest in the unconventional secretion of amyloids from neurons has followed. Amphisomes and late endosomes are the penultimate maturation products of the autophagosomal and endosomal pathways, respectively, and normally fuse with lysosomes for degradation. However, under conditions of perturbed membrane trafficking and/or lysosomal deficiency, prelysosomal compartments may instead fuse with the plasma membrane to release any contained amyloid. After a brief introduction to the endosomal and autophagosomal pathways, we discuss the evidence for autophagosomal secretion (exophagy) of amyloids, with a comparative emphasis on Aβ1-42 and α-synuclein, as luminal and cytosolic amyloids, respectively. The ESCRT-mediated import of cytosolic amyloid into late endosomal exosomes, a known vehicle of transmission of macromolecules between cells, is also reviewed. Finally, mechanisms of lysosomal dysfunction, deficiency, and exocytosis are exemplified in the context of genetically identified risk factors, mainly for Parkinson's disease. Exocytosis of prelysosomal or lysosomal organelles is a last resort for clearance of cytotoxic material and alleviates cytopathy. However, they also represent a vehicle for the concentration, posttranslational modification, and secretion of amyloid seeds.
Collapse
Affiliation(s)
- Helena Borland
- Department of Neurodegeneration In Vitro, H. Lundbeck A/S, 2500 Valby, Denmark.
| | - Frederik Vilhardt
- Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, 2200N Copenhagen, Denmark.
| |
Collapse
|
68
|
Bohmbach K, Schwarz MK, Schoch S, Henneberger C. The structural and functional evidence for vesicular release from astrocytes in situ. Brain Res Bull 2017; 136:65-75. [PMID: 28122264 DOI: 10.1016/j.brainresbull.2017.01.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/17/2017] [Accepted: 01/19/2017] [Indexed: 12/31/2022]
Abstract
The concept of the tripartite synapse states that bi-directional signalling between perisynaptic astrocyte processes, presynaptic axonal boutons and postsynaptic neuronal structures defines the properties of synaptic information processing. Ca2+-dependent vesicular release from astrocytes, as one of the mechanisms of astrocyte-neuron communication, has attracted particular attention but has also been the subject of intense debate. In neurons, regulated vesicular release is a strongly coordinated process. It requires a complex release machinery comprised of many individual components ranging from vesicular neurotransmitter transporters and soluble NSF attachment protein receptors (SNARE) proteins to Ca2+-sensors and the proteins that spatially and temporally control exocytosis of synaptic vesicles. If astrocytes employ similar mechanisms to release neurotransmitters is less well understood. The aim of this review is therefore to discuss recent experimental evidence that sheds light on the central structural components responsible for vesicular release from astrocytes in situ.
Collapse
Affiliation(s)
- Kirsten Bohmbach
- Institute of Cellular Neurosciences, University of Bonn Medical School, Bonn, Germany.
| | - Martin K Schwarz
- Department of Epileptology, University of Bonn Medical School, Bonn, Germany
| | - Susanne Schoch
- Institute of Neuropathology, University of Bonn Medical School, Bonn, Germany
| | - Christian Henneberger
- Institute of Cellular Neurosciences, University of Bonn Medical School, Bonn, Germany; German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany; Institute of Neurology, University College London, London, United Kingdom.
| |
Collapse
|
69
|
ER-endosome contact sites in endosome positioning and protrusion outgrowth. Biochem Soc Trans 2016; 44:441-6. [PMID: 27068952 DOI: 10.1042/bst20150246] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Indexed: 01/09/2023]
Abstract
The endoplasmic reticulum (ER) makes abundant contacts with endosomes, and the numbers of contact sites increase as endosomes mature. It is already clear that such contact sites have diverse compositions and functions, but in this mini-review we will focus on two particular types of ER-endosome contact sites that regulate endosome positioning. Formation of ER-endosome contact sites that contain the cholesterol-binding protein oxysterol-binding protein-related protein 1L (ORP1L) is coordinated with loss of the minus-end-directed microtubule motor Dynein from endosomes. Conversely, formation of ER-endosome contact sites that contain the Kinesin-1-binding protein Protrudin results in transfer of the plus-end-directed microtubule motor Kinesin-1 from ER to endosomes. We discuss the possibility that formation of these two types of contact sites is coordinated as a 'gear-shift' mechanism for endosome motility, and we review evidence that Kinesin-1-mediated motility of late endosomes (LEs) to the cell periphery promotes outgrowth of neurites and other protrusions.
Collapse
|
70
|
Padamsey Z, McGuinness L, Bardo SJ, Reinhart M, Tong R, Hedegaard A, Hart ML, Emptage NJ. Activity-Dependent Exocytosis of Lysosomes Regulates the Structural Plasticity of Dendritic Spines. Neuron 2016; 93:132-146. [PMID: 27989455 PMCID: PMC5222721 DOI: 10.1016/j.neuron.2016.11.013] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 09/02/2016] [Accepted: 10/31/2016] [Indexed: 11/28/2022]
Abstract
Lysosomes have traditionally been viewed as degradative organelles, although a growing body of evidence suggests that they can function as Ca2+ stores. Here we examined the function of these stores in hippocampal pyramidal neurons. We found that back-propagating action potentials (bpAPs) could elicit Ca2+ release from lysosomes in the dendrites. This Ca2+ release triggered the fusion of lysosomes with the plasma membrane, resulting in the release of Cathepsin B. Cathepsin B increased the activity of matrix metalloproteinase 9 (MMP-9), an enzyme involved in extracellular matrix (ECM) remodelling and synaptic plasticity. Inhibition of either lysosomal Ca2+ signaling or Cathepsin B release prevented the maintenance of dendritic spine growth induced by Hebbian activity. This impairment could be rescued by exogenous application of active MMP-9. Our findings suggest that activity-dependent exocytosis of Cathepsin B from lysosomes regulates the long-term structural plasticity of dendritic spines by triggering MMP-9 activation and ECM remodelling. Back-propagating action potentials induce Ca2+ release from lysosomes in neurons Lysosomal Ca2+ release triggers exocytosis of the lysosomal protease Cathepsin B Cathepsin B maintains activity-dependent dendritic spine growth by activating MMP-9
Collapse
Affiliation(s)
- Zahid Padamsey
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Lindsay McGuinness
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Scott J Bardo
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Marcia Reinhart
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Rudi Tong
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Anne Hedegaard
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Michael L Hart
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Nigel J Emptage
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
| |
Collapse
|
71
|
Wolfes AC, Ahmed S, Awasthi A, Stahlberg MA, Rajput A, Magruder DS, Bonn S, Dean C. A novel method for culturing stellate astrocytes reveals spatially distinct Ca2+ signaling and vesicle recycling in astrocytic processes. J Gen Physiol 2016; 149:149-170. [PMID: 27908976 PMCID: PMC5217085 DOI: 10.1085/jgp.201611607] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 11/09/2016] [Accepted: 11/11/2016] [Indexed: 12/20/2022] Open
Abstract
Communication between astrocytes and neurons has been difficult to study because cultured astrocytes do not resemble those in vivo. Wolfes et al. develop a stellate astrocyte monoculture with physiological characteristics and find that VAMP2 and SYT7 mark distinct vesicle populations in astrocytes. Interactions between astrocytes and neurons rely on the release and uptake of glial and neuronal molecules. But whether astrocytic vesicles exist and exocytose in a regulated or constitutive fashion is under debate. The majority of studies have relied on indirect methods or on astrocyte cultures that do not resemble stellate astrocytes found in vivo. Here, to investigate vesicle-associated proteins and exocytosis in stellate astrocytes specifically, we developed a simple, fast, and economical method for growing stellate astrocyte monocultures. This method is superior to other monocultures in terms of astrocyte morphology, mRNA expression profile, protein expression of cell maturity markers, and Ca2+ fluctuations: In astrocytes transduced with GFAP promoter–driven Lck-GCaMP3, spontaneous Ca2+ events in distinct domains (somata, branchlets, and microdomains) are similar to those in astrocytes co-cultured with other glia and neurons but unlike Ca2+ events in astrocytes prepared using the McCarthy and de Vellis (MD) method and immunopanned (IP) astrocytes. We identify two distinct populations of constitutively recycling vesicles (harboring either VAMP2 or SYT7) specifically in branchlets of cultured stellate astrocytes. SYT7 is developmentally regulated in these astrocytes, and we observe significantly fewer synapses in wild-type mouse neurons grown on Syt7−/− astrocytes. SYT7 may thus be involved in trafficking or releasing synaptogenic factors. In summary, our novel method yields stellate astrocyte monocultures that can be used to study Ca2+ signaling and vesicle recycling and dynamics in astrocytic processes.
Collapse
Affiliation(s)
- Anne C Wolfes
- Trans-Synaptic Signaling Group, European Neuroscience Institute Göttingen, 37077 Göttingen, Germany
| | - Saheeb Ahmed
- Trans-Synaptic Signaling Group, European Neuroscience Institute Göttingen, 37077 Göttingen, Germany
| | - Ankit Awasthi
- Trans-Synaptic Signaling Group, European Neuroscience Institute Göttingen, 37077 Göttingen, Germany
| | - Markus A Stahlberg
- Trans-Synaptic Signaling Group, European Neuroscience Institute Göttingen, 37077 Göttingen, Germany
| | - Ashish Rajput
- Research Group for Computational Systems Biology, German Center for Neurodegenerative Disease (DZNE), 37075 Göttingen, Germany
| | - Daniel S Magruder
- Research Group for Computational Systems Biology, German Center for Neurodegenerative Disease (DZNE), 37075 Göttingen, Germany
| | - Stefan Bonn
- Research Group for Computational Systems Biology, German Center for Neurodegenerative Disease (DZNE), 37075 Göttingen, Germany
| | - Camin Dean
- Trans-Synaptic Signaling Group, European Neuroscience Institute Göttingen, 37077 Göttingen, Germany
| |
Collapse
|
72
|
Pinheiro PS, Houy S, Sørensen JB. C2-domain containing calcium sensors in neuroendocrine secretion. J Neurochem 2016; 139:943-958. [DOI: 10.1111/jnc.13865] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/17/2016] [Accepted: 10/05/2016] [Indexed: 12/11/2022]
Affiliation(s)
- Paulo S. Pinheiro
- Center for Neuroscience and Cell Biology; University of Coimbra; Coimbra Portugal
| | - Sébastien Houy
- Department of Neuroscience and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Jakob B. Sørensen
- Department of Neuroscience and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| |
Collapse
|
73
|
Boye TL, Nylandsted J. Annexins in plasma membrane repair. Biol Chem 2016; 397:961-9. [DOI: 10.1515/hsz-2016-0171] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/14/2016] [Indexed: 01/01/2023]
Abstract
Abstract
Disruption of the plasma membrane poses deadly threat to eukaryotic cells and survival requires a rapid membrane repair system. Recent evidence reveal various plasma membrane repair mechanisms, which are required for cells to cope with membrane lesions including membrane fusion and replacement strategies, remodeling of cortical actin cytoskeleton and vesicle wound patching. Members of the annexin protein family, which are Ca2+-triggered phospholipid-binding proteins emerge as important components of the plasma membrane repair system. Here, we discuss the mechanisms of plasma membrane repair involving annexins spanning from yeast to human cancer cells.
Collapse
|
74
|
ABC Transporter Subfamily D: Distinct Differences in Behavior between ABCD1-3 and ABCD4 in Subcellular Localization, Function, and Human Disease. BIOMED RESEARCH INTERNATIONAL 2016; 2016:6786245. [PMID: 27766264 PMCID: PMC5059523 DOI: 10.1155/2016/6786245] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/29/2016] [Indexed: 12/15/2022]
Abstract
ATP-binding cassette (ABC) transporters are one of the largest families of membrane-bound proteins and transport a wide variety of substrates across both extra- and intracellular membranes. They play a critical role in maintaining cellular homeostasis. To date, four ABC transporters belonging to subfamily D have been identified. ABCD1-3 and ABCD4 are localized to peroxisomes and lysosomes, respectively. ABCD1 and ABCD2 are involved in the transport of long and very long chain fatty acids (VLCFA) or their CoA-derivatives into peroxisomes with different substrate specificities, while ABCD3 is involved in the transport of branched chain acyl-CoA into peroxisomes. On the other hand, ABCD4 is deduced to take part in the transport of vitamin B12 from lysosomes into the cytosol. It is well known that the dysfunction of ABCD1 results in X-linked adrenoleukodystrophy, a severe neurodegenerative disease. Recently, it is reported that ABCD3 and ABCD4 are responsible for hepatosplenomegaly and vitamin B12 deficiency, respectively. In this review, the targeting mechanism and physiological functions of the ABCD transporters are summarized along with the related disease.
Collapse
|
75
|
Castro-Gomes T, Corrotte M, Tam C, Andrews NW. Plasma Membrane Repair Is Regulated Extracellularly by Proteases Released from Lysosomes. PLoS One 2016; 11:e0152583. [PMID: 27028538 PMCID: PMC4814109 DOI: 10.1371/journal.pone.0152583] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/16/2016] [Indexed: 12/28/2022] Open
Abstract
Eukaryotic cells rapidly repair wounds on their plasma membrane. Resealing is Ca2+-dependent, and involves exocytosis of lysosomes followed by massive endocytosis. Extracellular activity of the lysosomal enzyme acid sphingomyelinase was previously shown to promote endocytosis and wound removal. However, whether lysosomal proteases released during cell injury participate in resealing is unknown. Here we show that lysosomal proteases regulate plasma membrane repair. Extracellular proteolysis is detected shortly after cell wounding, and inhibition of this process blocks repair. Conversely, surface protein degradation facilitates plasma membrane resealing. The abundant lysosomal cysteine proteases cathepsin B and L, known to proteolytically remodel the extracellular matrix, are rapidly released upon cell injury and are required for efficient plasma membrane repair. In contrast, inhibition of aspartyl proteases or RNAi-mediated silencing of the lysosomal aspartyl protease cathepsin D enhances resealing, an effect associated with the accumulation of active acid sphingomyelinase on the cell surface. Thus, secreted lysosomal cysteine proteases may promote repair by facilitating membrane access of lysosomal acid sphingomyelinase, which promotes wound removal and is subsequently downregulated extracellularly by a process involving cathepsin D.
Collapse
Affiliation(s)
- Thiago Castro-Gomes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, 20742, United States of America
| | - Matthias Corrotte
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, 20742, United States of America
| | - Christina Tam
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, 20742, United States of America
| | - Norma W. Andrews
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, 20742, United States of America
- * E-mail:
| |
Collapse
|
76
|
The calcium sensor synaptotagmin 7 is required for synaptic facilitation. Nature 2016; 529:88-91. [PMID: 26738595 PMCID: PMC4729191 DOI: 10.1038/nature16507] [Citation(s) in RCA: 214] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 12/03/2015] [Indexed: 11/22/2022]
Abstract
It has been known for over 70 years that synaptic strength is dynamically regulated in a use-dependent manner1. At synapses with a low initial release probability, closely spaced presynaptic action potentials can result in facilitation, a short-term form of enhancement where each subsequent action potential evokes greater neurotransmitter release2. Facilitation can enhance neurotransmitter release manyfold and profoundly influence information transfer across synapses3, but the underlying mechanism remains a mystery. Among the proposed mechanisms is that a specialized calcium sensor for facilitation transiently increases the probability of release2,4 and is distinct from the fast sensors that mediate rapid neurotransmitter release. Yet such a sensor has never been identified, and its very existence has been disputed5,6. Here we show that synaptotagmin 7 (syt7) is a calcium sensor that is required for facilitation at multiple central synapses. In syt7 knockout mice, facilitation is eliminated even though the initial probability of release and presynaptic residual calcium signals are unaltered. Expression of wild-type syt7 in presynaptic neurons restored facilitation, whereas expression of a mutated syt7 with a calcium-insensitive C2A domain did not. By revealing the role of syt7 in synaptic facilitation, these results resolve a longstanding debate about a widespread form of short-term plasticity, and will enable future studies that may lead to a deeper understanding of the functional importance of facilitation.
Collapse
|
77
|
Wang H, Han S, Siao W, Song C, Xiang Y, Wu X, Cheng P, Li H, Jásik J, Mičieta K, Turňa J, Voigt B, Baluška F, Liu J, Wang Y, Zhao H. Arabidopsis Synaptotagmin 2 Participates in Pollen Germination and Tube Growth and Is Delivered to Plasma Membrane via Conventional Secretion. MOLECULAR PLANT 2015; 8:1737-50. [PMID: 26384245 DOI: 10.1016/j.molp.2015.09.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 08/18/2015] [Accepted: 09/05/2015] [Indexed: 05/15/2023]
Abstract
Arabidopsis synaptotagmin 2 (SYT2) has been reported to participate in an unconventional secretory pathway in somatic cells. Our results showed that SYT2 was expressed mainly in the pollen of Arabidopsis thaliana. The pollen of syt2 T-DNA and RNA interference mutant lines exhibited reduced total germination and impeded pollen tube growth. Analysis of the expression of SYT2-GFP fusion protein in the pollen tube indicates that SYT2 was localized to distinct, patchy compartments but could co-localize with the Golgi markers, BODIPY TR C5 ceramide and GmMan1-mCherry. However, SYT2-DsRed-E5 was localized to the plasma membrane in Arabidopsis suspension cells, in addition to the Golgi apparatus. The localization of SYT2 at the plasma membrane was further supported by immunofluorescence staining in pollen tubes. Moreover, brefeldin A treatment inhibited the transport of SYT2 to the plasma membrane and caused SYT2 to aggregate and form enlarged compartments. Truncation of the SYT2-C2AB domains also resulted in retention of SYT2 in the Golgi apparatus. An in vitro phospholipid-binding assay showed that SYT2-C2AB domains bind to the phospholipid membrane in a calcium-dependent manner. Take together, our results indicated that SYT2 was required for pollen germination and pollen tube growth, and was involved in conventional exocytosis.
Collapse
Affiliation(s)
- Hui Wang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China
| | - Shengcheng Han
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China
| | - Wei Siao
- Department of Plant Cell Biology, IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
| | - Chunqing Song
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China
| | - Yun Xiang
- School of Life Science, Lanzhou University, Lanzhou 730000, China
| | - Xiaorong Wu
- School of Life Science, Lanzhou University, Lanzhou 730000, China
| | - Pengyu Cheng
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China
| | - Hongjuan Li
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China
| | - Ján Jásik
- Comenius University Science Park, Comenius University, Bratislava, Mlynská dolina, 842 15 Bratislava 4, Slovakia
| | - Karol Mičieta
- Department of Botany, Faculty of Natural Sciences, Comenius University, Révová 39, 811 02 Bratislava 1, Slovakia
| | - Ján Turňa
- Department of Molecular Biology, Comenius University, Faculty of Natural Sciences, Mlynská dolina, pavilion B-2, 842 15 Bratislava 4, Slovakia
| | - Boris Voigt
- Department of Plant Cell Biology, IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
| | - František Baluška
- Department of Plant Cell Biology, IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany; Institute of Botany, Slovak Academy of Sciences, Dubravska cesta 9, SK-84523 Bratislava, Slovak Republic.
| | - Jin Liu
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China
| | - Yingdian Wang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China
| | - Heping Zhao
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China.
| |
Collapse
|
78
|
Mahmoodzadeh Hosseini H, Halabian R, Amin M, Imani Fooladi AA. Texosome-based drug delivery system for cancer therapy: from past to present. Cancer Biol Med 2015; 12:150-62. [PMID: 26487960 PMCID: PMC4607826 DOI: 10.7497/j.issn.2095-3941.2015.0045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Rising worldwide cancer incidence and resistance to current anti-cancer drugs necessitate the need for new pharmaceutical compounds and drug delivery system. Malfunction of the immune system, particularly in the tumor microenvironment, causes tumor growth and enhances tumor progression. Thus, cancer immunotherapy can be an appropriate approach to provoke the systemic immune system to combat tumor expansion. Texosomes, which are endogenous nanovesicles released by all tumor cells, contribute to cell-cell communication and modify the phenotypic features of recipient cells due to the texosomes' ability to transport biological components. For this reason, texosome-based delivery system can be a valuable strategy for therapeutic purposes. To improve the pharmaceutical behavior of this system and to facilitate its use in medical applications, biotechnology approaches and mimetic techniques have been utilized. In this review, we present the development history of texosome-based delivery systems and discuss the advantages and disadvantages of each system.
Collapse
Affiliation(s)
- Hamideh Mahmoodzadeh Hosseini
- 1 Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran 1435916471, Iran ; 2 Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 1417653861, Iran
| | - Raheleh Halabian
- 1 Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran 1435916471, Iran ; 2 Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 1417653861, Iran
| | - Mohsen Amin
- 1 Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran 1435916471, Iran ; 2 Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 1417653861, Iran
| | - Abbas Ali Imani Fooladi
- 1 Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran 1435916471, Iran ; 2 Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 1417653861, Iran
| |
Collapse
|
79
|
Sreetama SC, Takano T, Nedergaard M, Simon SM, Jaiswal JK. Injured astrocytes are repaired by Synaptotagmin XI-regulated lysosome exocytosis. Cell Death Differ 2015; 23:596-607. [PMID: 26450452 DOI: 10.1038/cdd.2015.124] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 08/03/2015] [Accepted: 08/17/2015] [Indexed: 12/21/2022] Open
Abstract
Astrocytes are known to facilitate repair following brain injury; however, little is known about how injured astrocytes repair themselves. Repair of cell membrane injury requires Ca(2+)-triggered vesicle exocytosis. In astrocytes, lysosomes are the main Ca(2+)-regulated exocytic vesicles. Here we show that astrocyte cell membrane injury results in a large and rapid calcium increase. This triggers robust lysosome exocytosis where the fusing lysosomes release all luminal contents and merge fully with the plasma membrane. In contrast to this, receptor stimulation produces a small sustained calcium increase, which is associated with partial release of the lysosomal luminal content, and the lysosome membrane does not merge into the plasma membrane. In most cells, lysosomes express the synaptotagmin (Syt) isoform Syt VII; however, this isoform is not present on astrocyte lysosomes and exogenous expression of Syt VII on lysosome inhibits their exocytosis. Deletion of one of the most abundant Syt isoform in astrocyte--Syt XI--suppresses astrocyte lysosome exocytosis. This identifies lysosome as Syt XI-regulated exocytic vesicle in astrocytes. Further, inhibition of lysosome exocytosis (by Syt XI depletion or Syt VII expression) prevents repair of injured astrocytes. These results identify the lysosomes and Syt XI as the sub-cellular and molecular regulators, respectively of astrocyte cell membrane repair.
Collapse
Affiliation(s)
- S C Sreetama
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA
| | - T Takano
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY, USA
| | - M Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY, USA
| | - S M Simon
- Laboratory of Cellular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY, USA
| | - J K Jaiswal
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA.,Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, 111 Michigan Avenue NW, Washington, DC, USA
| |
Collapse
|
80
|
Plasma membrane and cytoskeleton dynamics during single-cell wound healing. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015. [DOI: 10.1016/j.bbamcr.2015.07.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
81
|
Andrews NW, Corrotte M, Castro-Gomes T. Above the fray: Surface remodeling by secreted lysosomal enzymes leads to endocytosis-mediated plasma membrane repair. Semin Cell Dev Biol 2015; 45:10-7. [PMID: 26433178 DOI: 10.1016/j.semcdb.2015.09.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 09/28/2015] [Indexed: 11/16/2022]
Abstract
The study of plasma membrane repair is coming of age. Mirroring human adolescence, the field shows at the same time signs of maturity and significant uncertainty, confusion and skepticism. Here we discuss concepts that emerged from experimental data over the years, some of which are solidly established while others are still subject to different interpretations. The firmly established concepts include the critical requirement for Ca(2+) in wound repair, and the role of rapid exocytosis of intracellular vesicles. Lysosomes are being increasingly recognized as the major vesicles involved in injury-induced exocytosis in many cell types, as a growing number of laboratories detect markers for these organelles on the cell surface and lysosomal hydrolases in the supernatant of wounded cells. The more recent observation of massive endocytosis following Ca(2+)-triggered exocytosis initially came as a surprise, but this finding is also being increasingly reported by different groups, shifting the discussion to the mechanisms by which endocytosis promotes repair, and whether it operates or not in parallel with the shedding of membrane blebs. We discuss how the abundant intracellular vesicles that undergo homotypic fusion close to wound sites, previously interpreted as exocytic membrane patches, actually acquire extracellular tracers demonstrating their endocytic origin. We also suggest that an initial, temporary patch that prevents cytosol loss until the bilayer is restored might result not from vesicular fusion, but from rapid Ca(2+)-dependent crosslinking and aggregation of cytosolic proteins. Finally, we propose that cell surface remodeling, orchestrated by the extracellular release of lysosomal hydrolases and perhaps also cytosolic molecules, may represent a key aspect of the plasma membrane repair mechanism that has received little attention so far.
Collapse
Affiliation(s)
- N W Andrews
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA.
| | - M Corrotte
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - T Castro-Gomes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| |
Collapse
|
82
|
Cao Q, Zhong XZ, Zou Y, Murrell-Lagnado R, Zhu MX, Dong XP. Calcium release through P2X4 activates calmodulin to promote endolysosomal membrane fusion. J Cell Biol 2015; 209:879-94. [PMID: 26101220 PMCID: PMC4477861 DOI: 10.1083/jcb.201409071] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
P2X4 and calmodulin form a signaling complex in late endosomes and lysosomes that promotes fusion and vacuolation in a Ca2+-dependent fashion. Intra-endolysosomal Ca2+ release is required for endolysosomal membrane fusion with intracellular organelles. However, the molecular mechanisms for intra-endolysosomal Ca2+ release and the downstream Ca2+ targets involved in the fusion remain elusive. Previously, we demonstrated that endolysosomal P2X4 forms channels activated by luminal adenosine triphosphate in a pH-dependent manner. In this paper, we show that overexpression of P2X4, as well as increasing endolysosomal P2X4 activity by alkalinization of endolysosome lumen, promoted vacuole enlargement in cells and endolysosome fusion in a cell-free assay. These effects were prevented by inhibiting P2X4, expressing a dominant-negative P2X4 mutant, and disrupting the P2X4 gene. We further show that P2X4 and calmodulin (CaM) form a complex at endolysosomal membrane where P2X4 activation recruits CaM to promote fusion and vacuolation in a Ca2+-dependent fashion. Moreover, P2X4 activation-triggered fusion and vacuolation were suppressed by inhibiting CaM. Our data thus suggest a new molecular mechanism for endolysosomal membrane fusion involving P2X4-mediated endolysosomal Ca2+ release and subsequent CaM activation.
Collapse
Affiliation(s)
- Qi Cao
- Department of Physiology and Biophysics, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
| | - Xi Zoë Zhong
- Department of Physiology and Biophysics, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
| | - Yuanjie Zou
- Department of Physiology and Biophysics, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
| | - Ruth Murrell-Lagnado
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, England, UK
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030
| | - Xian-Ping Dong
- Department of Physiology and Biophysics, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
| |
Collapse
|
83
|
de Morais CGV, Castro Lima AK, Terra R, dos Santos RF, Da-Silva SAG, Dutra PML. The Dialogue of the Host-Parasite Relationship: Leishmania spp. and Trypanosoma cruzi Infection. BIOMED RESEARCH INTERNATIONAL 2015; 2015:324915. [PMID: 26090399 PMCID: PMC4450238 DOI: 10.1155/2015/324915] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/01/2014] [Accepted: 09/02/2014] [Indexed: 01/11/2023]
Abstract
The intracellular protozoa Leishmania spp. and Trypanosoma cruzi and the causative agents of Leishmaniasis and Chagas disease, respectively, belong to the Trypanosomatidae family. Together, these two neglected tropical diseases affect approximately 25 million people worldwide. Whether the host can control the infection or develops disease depends on the complex interaction between parasite and host. Parasite surface and secreted molecules are involved in triggering specific signaling pathways essential for parasite entry and intracellular survival. The recognition of the parasite antigens by host immune cells generates a specific immune response. Leishmania spp. and T. cruzi have a multifaceted repertoire of strategies to evade or subvert the immune system by interfering with a range of signal transduction pathways in host cells, which causes the inhibition of the protective response and contributes to their persistence in the host. The current therapeutic strategies in leishmaniasis and trypanosomiasis are very limited. Efficacy is variable, toxicity is high, and the emergence of resistance is increasingly common. In this review, we discuss the molecular basis of the host-parasite interaction of Leishmania and Trypanosoma cruzi infection and their mechanisms of subverting the immune response and how this knowledge can be used as a tool for the development of new drugs.
Collapse
Affiliation(s)
- Carlos Gustavo Vieira de Morais
- Laboratório de Bioquímica de Protozoários e Imunofisiologia do Exercício, Disciplina de Parasitologia, DMIP, FCM, Universidade do Estado do Rio de Janeiro, Avenida Professor Manuel de Abreu 444, Pavilhão Américo Piquet Carneiro, 5° andar, Vila Isabel, 20550-170 Rio de Janeiro, RJ, Brazil
- Programa de Pós Graduação em Microbiologia/FCM/UERJ, Avenida Professor Manuel de Abreu 444, Pavilhão Américo Piquet Carneiro, 3° andar, Vila Isabel, 20550-170 Rio de Janeiro, RJ, Brazil
| | - Ana Karina Castro Lima
- Laboratório de Bioquímica de Protozoários e Imunofisiologia do Exercício, Disciplina de Parasitologia, DMIP, FCM, Universidade do Estado do Rio de Janeiro, Avenida Professor Manuel de Abreu 444, Pavilhão Américo Piquet Carneiro, 5° andar, Vila Isabel, 20550-170 Rio de Janeiro, RJ, Brazil
| | - Rodrigo Terra
- Laboratório de Bioquímica de Protozoários e Imunofisiologia do Exercício, Disciplina de Parasitologia, DMIP, FCM, Universidade do Estado do Rio de Janeiro, Avenida Professor Manuel de Abreu 444, Pavilhão Américo Piquet Carneiro, 5° andar, Vila Isabel, 20550-170 Rio de Janeiro, RJ, Brazil
- Programa de Pós Graduação em Fisiopatologia Clínica e Experimental/FCM/UERJ, Avenida Professor Manuel de Abreu 444, Pavilhão Américo Piquet Carneiro, 5° andar, Vila Isabel, 20550-170 Rio de Janeiro, RJ, Brazil
| | - Rosiane Freire dos Santos
- Programa de Pós Graduação em Microbiologia/FCM/UERJ, Avenida Professor Manuel de Abreu 444, Pavilhão Américo Piquet Carneiro, 3° andar, Vila Isabel, 20550-170 Rio de Janeiro, RJ, Brazil
- Laboratório de Imunofarmacologia Parasitária, Disciplina de Parasitologia, DMIP, FCM, Universidade do Estado do Rio de Janeiro, Avenida Professor Manuel de Abreu 444, Pavilhão Américo Piquet Carneiro, 5° andar, Vila Isabel, 20550-170 Rio de Janeiro, RJ, Brazil
| | - Silvia Amaral Gonçalves Da-Silva
- Laboratório de Imunofarmacologia Parasitária, Disciplina de Parasitologia, DMIP, FCM, Universidade do Estado do Rio de Janeiro, Avenida Professor Manuel de Abreu 444, Pavilhão Américo Piquet Carneiro, 5° andar, Vila Isabel, 20550-170 Rio de Janeiro, RJ, Brazil
| | - Patrícia Maria Lourenço Dutra
- Laboratório de Bioquímica de Protozoários e Imunofisiologia do Exercício, Disciplina de Parasitologia, DMIP, FCM, Universidade do Estado do Rio de Janeiro, Avenida Professor Manuel de Abreu 444, Pavilhão Américo Piquet Carneiro, 5° andar, Vila Isabel, 20550-170 Rio de Janeiro, RJ, Brazil
| |
Collapse
|
84
|
Sung BH, Ketova T, Hoshino D, Zijlstra A, Weaver AM. Directional cell movement through tissues is controlled by exosome secretion. Nat Commun 2015; 6:7164. [PMID: 25968605 PMCID: PMC4435734 DOI: 10.1038/ncomms8164] [Citation(s) in RCA: 422] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 04/10/2015] [Indexed: 02/06/2023] Open
Abstract
Directional cell movement through tissues is critical for multiple biological processes and requires maintenance of polarity in the face of complex environmental cues. Here we use intravital imaging to demonstrate that secretion of exosomes from late endosomes is required for directionally persistent and efficient in vivo movement of cancer cells. Inhibiting exosome secretion or biogenesis leads to defective tumour cell migration associated with increased formation of unstable protrusions and excessive directional switching. In vitro rescue experiments with purified exosomes and matrix coating identify adhesion assembly as a critical exosome function that promotes efficient cell motility. Live-cell imaging reveals that exosome secretion directly precedes and promotes adhesion assembly. Fibronectin is found to be a critical motility-promoting cargo whose sorting into exosomes depends on binding to integrins. We propose that autocrine secretion of exosomes powerfully promotes directionally persistent and effective cell motility by reinforcing otherwise transient polarization states and promoting adhesion assembly.
Collapse
Affiliation(s)
- Bong Hwan Sung
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Tatiana Ketova
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Daisuke Hoshino
- Division of Cancer Cell Research, Kanagawa Cancer Center, Yokohama 241-8515, Japan
| | - Andries Zijlstra
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Alissa M. Weaver
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| |
Collapse
|
85
|
Neuland K, Frick M. Vesicular control of fusion pore expansion. Commun Integr Biol 2015; 8:e1018496. [PMID: 26479858 PMCID: PMC4594593 DOI: 10.1080/19420889.2015.1018496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 02/02/2015] [Accepted: 02/07/2015] [Indexed: 11/16/2022] Open
Abstract
Exocytic post-fusion events play an important role determining the composition and quantity of cellular secretion. In particular, Ca2+-dependent regulation of fusion pore dilation/closure is a key regulator for fine-tuning vesicle content secretion. This requires a tight temporal and spatial integration of vesicle fusion with the PM, Ca2+ signals and translation of the Ca2+ signal into fusion pore dilation via auxiliary factors. Yet, it is still mostly elusive how this is achieved in slow and non-excitable secretory cells, where initial Ca2+ signals triggering fusions will abate before onset of the post-fusion phase. New results suggest, that the vesicles themselves provide the necessary itinerary to sense and link vesicle fusion to generation of local Ca2+ signals and fusion pore expansion.
Collapse
Affiliation(s)
- Kathrin Neuland
- Institute of General Physiology; University of Ulm ; Ulm, Germany
| | - Manfred Frick
- Institute of General Physiology; University of Ulm ; Ulm, Germany
| |
Collapse
|
86
|
Differential fates of biomolecules delivered to target cells via extracellular vesicles. Proc Natl Acad Sci U S A 2015; 112:E1433-42. [PMID: 25713383 DOI: 10.1073/pnas.1418401112] [Citation(s) in RCA: 351] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Extracellular vesicles (EVs), specifically exosomes and microvesicles (MVs), are presumed to play key roles in cell-cell communication via transfer of biomolecules between cells. The biogenesis of these two types of EVs differs as they originate from either the endosomal (exosomes) or plasma (MVs) membranes. To elucidate the primary means through which EVs mediate intercellular communication, we characterized their ability to encapsulate and deliver different types of macromolecules from transiently transfected cells. Both EV types encapsulated reporter proteins and mRNA but only MVs transferred the reporter function to recipient cells. De novo reporter protein expression in recipient cells resulted only from plasmid DNA (pDNA) after delivery via MVs. Reporter mRNA was delivered to recipient cells by both EV types, but was rapidly degraded without being translated. MVs also mediated delivery of functional pDNA encoding Cre recombinase in vivo to tissues in transgenic Cre-lox reporter mice. Within the parameters of this study, MVs delivered functional pDNA, but not RNA, whereas exosomes from the same source did not deliver functional nucleic acids. These results have significant implications for understanding the role of EVs in cellular communication and for development of EVs as delivery tools. Moreover, studies using EVs from transiently transfected cells may be confounded by a predominance of pDNA transfer.
Collapse
|
87
|
Aryani A, Denecke B. Exosomes as a Nanodelivery System: a Key to the Future of Neuromedicine? Mol Neurobiol 2014; 53:818-834. [PMID: 25502465 PMCID: PMC4752585 DOI: 10.1007/s12035-014-9054-5] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 12/05/2014] [Indexed: 01/04/2023]
Abstract
Since the beginning of the last decade, exosomes have been of increased interest in the science community. Exosomes represent a new kind of long distance transfer of biological molecules among cells. This review provides a comprehensive overview about the construction of exosomes, their targeting and their fusion mechanisms to the recipient cells. Complementarily, the current state of research regarding the cargo of exosomes is discussed. A particular focus was placed on the role of exosomes in the central nervous system. An increasing number of physiological processes in the brain could be associated with exosomes. In this context, it is becoming more apparent that exosomes are involved in several neurological and specifically neurodegenerative diseases. The treatment of these kinds of diseases is often difficult not least because of the blood-brain barrier. Exosomes are very stable, can pass the blood-brain barrier and, therefore, reveal bright perspectives towards diagnosis and therapeutic treatments. A prerequisite for clinical applications is a standardised approach. Features necessary for a standardised diagnosis using exosomes are discussed. In therapeutic terms, exosomes represent a promising drug delivery system able to pass the blood-brain barrier. One option to overcome the disadvantages potentially associated with the use of endogenous exosomes is the design of artificial exosomes. The artificial exosomes with a clearly defined therapeutic active cargo and surface marker ensuring the specific targeting to the recipient cells is proposed as a promising approach.
Collapse
Affiliation(s)
- Arian Aryani
- Interdisciplinary Center for Clinical Research Aachen (IZKF Aachen), RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Bernd Denecke
- Interdisciplinary Center for Clinical Research Aachen (IZKF Aachen), RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany.
| |
Collapse
|
88
|
Weber JP, Toft-Bertelsen TL, Mohrmann R, Delgado-Martinez I, Sørensen JB. Synaptotagmin-7 is an asynchronous calcium sensor for synaptic transmission in neurons expressing SNAP-23. PLoS One 2014; 9:e114033. [PMID: 25422940 PMCID: PMC4244210 DOI: 10.1371/journal.pone.0114033] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 11/03/2014] [Indexed: 12/25/2022] Open
Abstract
Synchronization of neurotransmitter release with the presynaptic action potential is essential for maintaining fidelity of information transfer in the central nervous system. However, synchronous release is frequently accompanied by an asynchronous release component that builds up during repetitive stimulation, and can even play a dominant role in some synapses. Here, we show that substitution of SNAP-23 for SNAP-25 in mouse autaptic glutamatergic hippocampal neurons results in asynchronous release and a higher frequency of spontaneous release events (mEPSCs). Use of neurons from double-knock-out (SNAP-25, synaptotagmin-7) mice in combination with viral transduction showed that SNAP-23-driven release is triggered by endogenous synaptotagmin-7. In the absence of synaptotagmin-7 release became even more asynchronous, and the spontaneous release rate increased even more, indicating that synaptotagmin-7 acts to synchronize release and suppress spontaneous release. However, compared to synaptotagmin-1, synaptotagmin-7 is a both leaky and asynchronous calcium sensor. In the presence of SNAP-25, consequences of the elimination of synaptotagmin-7 were small or absent, indicating that the protein pairs SNAP-25/synaptotagmin-1 and SNAP-23/synaptotagmin-7 might act as mutually exclusive calcium sensors. Expression of fusion proteins between pHluorin (pH-sensitive GFP) and synaptotagmin-1 or -7 showed that vesicles that fuse using the SNAP-23/synaptotagmin-7 combination contained synaptotagmin-1, while synaptotagmin-7 barely displayed activity-dependent trafficking between vesicle and plasma membrane, implying that it acts as a plasma membrane calcium sensor. Overall, these findings support the idea of alternative syt∶SNARE combinations driving release with different kinetics and fidelity.
Collapse
Affiliation(s)
- Jens P. Weber
- Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, The Netherlands
| | - Trine L. Toft-Bertelsen
- Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ralf Mohrmann
- Department of Physiology, University of Saarland, Homburg, Germany
| | | | - Jakob B. Sørensen
- Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- Lundbeck Foundation Center for Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
89
|
Neuland K, Sharma N, Frick M. Synaptotagmin-7 links fusion-activated Ca²⁺ entry and fusion pore dilation. J Cell Sci 2014; 127:5218-27. [PMID: 25344253 PMCID: PMC4265738 DOI: 10.1242/jcs.153742] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Ca(2+)-dependent regulation of fusion pore dilation and closure is a key mechanism determining the output of cellular secretion. We have recently described 'fusion-activated' Ca(2+) entry (FACE) following exocytosis of lamellar bodies in alveolar type II cells. FACE regulates fusion pore expansion and facilitates secretion. However, the mechanisms linking this locally restricted Ca(2+) signal and fusion pore expansion were still elusive. Here, we demonstrate that synaptotagmin-7 (Syt7) is expressed on lamellar bodies and links FACE and fusion pore dilation. We directly assessed dynamic changes in fusion pore diameters by analysing diffusion of fluorophores across fusion pores. Expressing wild-type Syt7 or a mutant Syt7 with impaired Ca(2+)-binding to the C2 domains revealed that binding of Ca(2+) to the C2A domain facilitates FACE-induced pore dilation, probably by inhibiting translocation of complexin-2 to fused vesicles. However, the C2A domain hampered Ca(2+)-dependent exocytosis of lamellar bodies. These findings support the hypothesis that Syt7 modulates fusion pore expansion in large secretory organelles and extend our picture that lamellar bodies contain the necessary molecular inventory to facilitate secretion during the exocytic post-fusion phase. Moreover, regulating Syt7 levels on lamellar bodies appears to be essential in order that exocytosis is not impeded during the pre-fusion phase.
Collapse
Affiliation(s)
- Kathrin Neuland
- Institute of General Physiology, University of Ulm, Albert-Einstein Allee 11, 89081 Ulm, Germany
| | - Neeti Sharma
- Institute of General Physiology, University of Ulm, Albert-Einstein Allee 11, 89081 Ulm, Germany
| | - Manfred Frick
- Institute of General Physiology, University of Ulm, Albert-Einstein Allee 11, 89081 Ulm, Germany
| |
Collapse
|
90
|
Wäster P, Eriksson I, Vainikka L, Ollinger K. Sunbathing: What've lysosomes got to do with it? Commun Integr Biol 2014; 7:e28723. [PMID: 25346791 PMCID: PMC4201597 DOI: 10.4161/cib.28723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/31/2014] [Accepted: 03/31/2014] [Indexed: 12/27/2022] Open
Abstract
Solar radiation is an important risk factor for skin cancer, the incidence of which is increasing, especially in the fair-skinned populations of the world. While the ultraviolet (UV)B component has direct DNA damaging ability, UVA-induced effects are currently mainly attributed to the production of reactive oxygen species. In our recent study, we compared the effects of UVA and UVB radiation on human keratinocytes and found that UVA-induced plasma membrane damage was rapidly repaired by lysosomal exocytosis, which was detected based on the expression of lysosomal membrane associated protein-1 (LAMP-1) on the plasma membrane of non-permeabilized cells. Later, the keratinocytes died through caspase-8 mediated apoptosis. In contrast, the plasma membranes of keratinocytes exposed to UVB showed no LAMP-1 expression, and, although the cells died by apoptosis, no initial caspase-8 activity was detected. We have also demonstrated the occurrence of UVA-induced lysosomal exocytosis in reconstructed skin and shown the relocation of lysosomes from the center of cells to the vicinity of the plasma membrane. Thus, we suggest that lysosomal exocytosis also occurs in keratinocytes covered by the stratum corneum following exposure to UVA. Our findings provide new insight into the mechanism of UVA-induced skin damage.
Collapse
Affiliation(s)
- Petra Wäster
- Division of Experimental Pathology; Department of Clinical and Experimental Medicine; Faculty of Health Science; Linköping University; Linköping, Sweden
| | - Ida Eriksson
- Division of Experimental Pathology; Department of Clinical and Experimental Medicine; Faculty of Health Science; Linköping University; Linköping, Sweden
| | - Linda Vainikka
- Division of Experimental Pathology; Department of Clinical and Experimental Medicine; Faculty of Health Science; Linköping University; Linköping, Sweden
| | - Karin Ollinger
- Division of Experimental Pathology; Department of Clinical and Experimental Medicine; Faculty of Health Science; Linköping University; Linköping, Sweden
| |
Collapse
|
91
|
Appelqvist H, Wäster P, Kågedal K, Öllinger K. The lysosome: from waste bag to potential therapeutic target. J Mol Cell Biol 2014; 5:214-26. [PMID: 23918283 DOI: 10.1093/jmcb/mjt022] [Citation(s) in RCA: 530] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Lysosomes are ubiquitous membrane-bound intracellular organelles with an acidic interior. They are central for degradation and recycling of macromolecules delivered by endocytosis, phagocytosis, and autophagy. In contrast to the rather simplified view of lysosomes as waste bags, nowadays lysosomes are recognized as advanced organelles involved in many cellular processes and are considered crucial regulators of cell homeostasis. The function of lysosomes is critically dependent on soluble lysosomal hydrolases (e.g. cathepsins) as well as lysosomal membrane proteins (e.g. lysosome-associated membrane proteins). This review focuses on lysosomal involvement in digestion of intra- and extracellular material, plasma membrane repair, cholesterol homeostasis, and cell death. Regulation of lysosomal biogenesis and function via the transcription factor EB (TFEB) will also be discussed. In addition, lysosomal contribution to diseases, including lysosomal storage disorders, neurodegenerative disorders, cancer, and cardiovascular diseases, is presented.
Collapse
Affiliation(s)
- Hanna Appelqvist
- Experimental Pathology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden
| | | | | | | |
Collapse
|
92
|
Hissa B, Pontes B, Roma PMS, Alves AP, Rocha CD, Valverde TM, Aguiar PHN, Almeida FP, Guimarães AJ, Guatimosim C, Silva AM, Fernandes MC, Andrews NW, Viana NB, Mesquita ON, Agero U, Andrade LO. Membrane cholesterol removal changes mechanical properties of cells and induces secretion of a specific pool of lysosomes. PLoS One 2013; 8:e82988. [PMID: 24376622 PMCID: PMC3869752 DOI: 10.1371/journal.pone.0082988] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/29/2013] [Indexed: 11/18/2022] Open
Abstract
In a previous study we had shown that membrane cholesterol removal induced unregulated lysosomal exocytosis events leading to the depletion of lysosomes located at cell periphery. However, the mechanism by which cholesterol triggered these exocytic events had not been uncovered. In this study we investigated the importance of cholesterol in controlling mechanical properties of cells and its connection with lysosomal exocytosis. Tether extraction with optical tweezers and defocusing microscopy were used to assess cell dynamics in mouse fibroblasts. These assays showed that bending modulus and surface tension increased when cholesterol was extracted from fibroblasts plasma membrane upon incubation with MβCD, and that the membrane-cytoskeleton relaxation time increased at the beginning of MβCD treatment and decreased at the end. We also showed for the first time that the amplitude of membrane-cytoskeleton fluctuation decreased during cholesterol sequestration, showing that these cells become stiffer. These changes in membrane dynamics involved not only rearrangement of the actin cytoskeleton, but also de novo actin polymerization and stress fiber formation through Rho activation. We found that these mechanical changes observed after cholesterol sequestration were involved in triggering lysosomal exocytosis. Exocytosis occurred even in the absence of the lysosomal calcium sensor synaptotagmin VII, and was associated with actin polymerization induced by MβCD. Notably, exocytosis triggered by cholesterol removal led to the secretion of a unique population of lysosomes, different from the pool mobilized by actin depolymerizing drugs such as Latrunculin-A. These data support the existence of at least two different pools of lysosomes with different exocytosis dynamics, one of which is directly mobilized for plasma membrane fusion after cholesterol removal.
Collapse
Affiliation(s)
- Barbara Hissa
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Bruno Pontes
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Paula Magda S. Roma
- Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ana Paula Alves
- Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Carolina D. Rocha
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Thalita M. Valverde
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Pedro Henrique N. Aguiar
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Fernando P. Almeida
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Allan J. Guimarães
- Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Rio de Janeiro, RJ, Brazil
| | - Cristina Guatimosim
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Aristóbolo M. Silva
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Maria C. Fernandes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
| | - Norma W. Andrews
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
| | - Nathan B. Viana
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Oscar N. Mesquita
- Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ubirajara Agero
- Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Luciana O. Andrade
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
- * E-mail:
| |
Collapse
|
93
|
Exocytosis of nanoparticles from cells: role in cellular retention and toxicity. Adv Colloid Interface Sci 2013; 201-202:18-29. [PMID: 24200091 DOI: 10.1016/j.cis.2013.10.013] [Citation(s) in RCA: 185] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 10/11/2013] [Accepted: 10/13/2013] [Indexed: 01/06/2023]
Abstract
Over the past decade, nanoparticles (NPs) have been increasingly developed in various biomedical applications such as cell tracking, biosensing, contrast imaging, targeted drug delivery, and tissue engineering. Their versatility in design and function has made them an attractive, alternative choice in many biological and biomedical applications. Cellular responses to NPs, their uptake, and adverse biological effects caused by NPs are rapidly-growing research niches. However, NP excretion and its underlying mechanisms and cell signaling pathways are yet elusive. In this review, we present an overview of how NPs are handled intracellularly and how they are excreted from cells following the uptake. We also discuss how exocytosis of nanomaterials impacts both the therapeutic delivery of nanoscale objects and their nanotoxicology.
Collapse
|
94
|
Upregulation of the Rab27a-dependent trafficking and secretory mechanisms improves lysosomal transport, alleviates endoplasmic reticulum stress, and reduces lysosome overload in cystinosis. Mol Cell Biol 2013; 33:2950-62. [PMID: 23716592 DOI: 10.1128/mcb.00417-13] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cystinosis is a lysosomal storage disorder caused by the accumulation of the amino acid cystine due to genetic defects in the CTNS gene, which encodes cystinosin, the lysosomal cystine transporter. Although many cellular dysfunctions have been described in cystinosis, the mechanisms leading to these defects are not well understood. Here, we show that increased lysosomal overload induced by accumulated cystine leads to cellular abnormalities, including vesicular transport defects and increased endoplasmic reticulum (ER) stress, and that correction of lysosomal transport improves cellular function in cystinosis. We found that Rab27a was expressed in proximal tubular cells (PTCs) and partially colocalized with the lysosomal marker LAMP-1. The expression of Rab27a but not other small GTPases, including Rab3 and Rab7, was downregulated in kidneys from Ctns-/- mice and in human PTCs from cystinotic patients. Using total internal reflection fluorescence microscopy, we found that lysosomal transport is impaired in Ctns-/- cells. Ctns-/- cells showed significant ER expansion and a marked increase in the unfolded protein response-induced chaperones Grp78 and Grp94. Upregulation of the Rab27a-dependent vesicular trafficking mechanisms rescued the defective lysosomal transport phenotype and reduced ER stress in cystinotic cells. Importantly, reconstitution of lysosomal transport mediated by Rab27a led to decreased lysosomal overload, manifested as reduced cystine cellular content. Our data suggest that upregulation of the Rab27a-dependent lysosomal trafficking and secretory pathways contributes to the correction of some of the cellular defects induced by lysosomal overload in cystinosis, including ER stress.
Collapse
|
95
|
Yanes RE, Tarn D, Hwang AA, Ferris DP, Sherman SP, Thomas CR, Lu J, Pyle AD, Zink JI, Tamanoi F. Involvement of lysosomal exocytosis in the excretion of mesoporous silica nanoparticles and enhancement of the drug delivery effect by exocytosis inhibition. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2013; 9:697-704. [PMID: 23152124 PMCID: PMC3767416 DOI: 10.1002/smll.201201811] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Indexed: 05/22/2023]
Abstract
The exocytosis of phosphonate modified mesoporous silica nanoparticles (P-MSNs) is demonstrated and lysosomal exocytosis is identified as the mechanism responsible for this event. Regulation of P-MSN exocytosis can be achieved by inhibiting or accelerating lysosomal exocytosis. Slowing down P-MSN exocytosis enhances the drug delivery effect of CPT-loaded P-MSNs by improving cell killing.
Collapse
Affiliation(s)
- Rolando E Yanes
- Department of Microbiology, California NanoSystems Institute, Jonsson Comprehensive Cancer Center, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, CA 90095, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
96
|
Campoy EM, Mansilla ME, Colombo MI. Endocytic SNAREs are involved in optimal Coxiella burnetii vacuole development. Cell Microbiol 2013; 15:922-41. [PMID: 23217169 DOI: 10.1111/cmi.12087] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Revised: 11/19/2012] [Accepted: 11/22/2012] [Indexed: 11/29/2022]
Abstract
Coxiella burnetii is a Gram-negative intracellular bacterium. As previously described, both the endocytic and the autophagic pathways contribute to the maturation of Coxiella replicative vacuoles (CRVs). The large CRVs share the properties of both phagolysosomal and autophagolysosomal compartments. Vamp3, Vamp7 and Vamp8 are v-SNAREs involved in the endocytic pathway which participate mainly in the fusion between endosomes and lysosomes. In the present study we observed that Vamp7 interacts with C. burnetii at different infection times (1 h-48 h p.i.). We have determined that a truncated mutant of Vamp7 (Vamp7 NT) and a siRNA against this SNARE protein affects the optimal development of CRVs, suggesting that Vamp7 mediates fusion events that are required for the biogenesis of CRVs. Indeed, we have observed that overexpression of Vamp7 NT inhibited the heterotypic fusion with lysosomes and the homotypic fusion between individual Coxiella phagosomes and CRVs. Moreover, we have detected in the vacuole membrane, at different infection times, the Vamp7 partners (Vti1a and Vti1b). Interestingly, treatment with chloramphenicol reduced the colocalization between C. burnetii and Vamp7, Vti1a or Vti1b, indicating that the recruitment of these SNAREs proteins is a bacteria-driven process that favours the CRV biogenesis, likely by facilitating the interaction with the endolysosomal compartment.
Collapse
Affiliation(s)
- Emanuel Martín Campoy
- Laboratorio de Biología Celular y Molecular- Instituto de Histología y Embriología IHEM, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo-CONICET, Mendoza, Argentina
| | | | | |
Collapse
|
97
|
Divangahi M, Behar SM, Remold H. Dying to live: how the death modality of the infected macrophage affects immunity to tuberculosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 783:103-20. [PMID: 23468106 DOI: 10.1007/978-1-4614-6111-1_6] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Virulent Mycobacterium tuberculosis (Mtb) inhibits apoptosis and triggers necrosis of host macrophages to evade innate delay in the initiation of adaptive immunity. Necrosis is a mechanism used by bacteria to exit macrophage, evade the host defenses, and disseminate while apoptosis is associated with diminished pathogen viability. We have recently demonstrated that eicosanoids regulate cell death program of either human or murine macrophages infected with Mtb. We have defined prostaglandin E2 (PGE2) as a pro-apoptotic host lipid mediator which protects against necrosis. In contrast, lipoxin A4 (LXA4) is a pro-necrotic lipid mediator which suppresses PGE2 synthesis, resulting in mitochondrial damage and inhibition of plasma membrane repair mechanisms; this ultimately leads to the induction of necrosis. Thus, the balance between PGE2 and LXA4 determines whether Mtb-infected macrophages undergo apoptosis or necrosis and this balance determines the outcome of infection.
Collapse
Affiliation(s)
- Maziar Divangahi
- Department of Microbiology and Immunology, McGill University Health Centre, Montreal, Canada.
| | | | | |
Collapse
|
98
|
Shin YH, Lee SJ, Jung J. Secretion of ATP from Schwann cells through lysosomal exocytosis during Wallerian degeneration. Biochem Biophys Res Commun 2012; 429:163-7. [PMID: 23142593 DOI: 10.1016/j.bbrc.2012.10.121] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 10/29/2012] [Indexed: 12/18/2022]
Abstract
The present study demonstrates that adenosine triphosphate (ATP) is released from Schwann cells through lysosomal exocytosis during Wallerian degeneration and in response to stimulation. In primary Schwann cell cultures, ATP was stored in lysosomal vesicles. ATP could then induce Ca(2+)-dependent lysosomal exocytosis. Among three stimulants of lysosomal exocytosis (glutamate, NH(4)Cl and zymosan), only NH(4)Cl was sufficient to induce ATP release from ex vivo sciatic nerve explants at 3 days in vitro. Lysosomal exocytosis inhibitors (metformin, chlorpromazine and vacuolin-1) reversed the effect of NH(4)Cl-enhanced ATP release, replicating the state of explants treated with NH(4)Cl in the absence of lysosomal exocytosis inhibitors. Furthermore, we observed ATP release through lysosomal exocytosis during Wallerian degeneration in sciatic explant cultures using the recently identified vesicular nucleotide transporter (VNUT). From these experiments, we conclude that the exocytosis of lysosomes in Schwann cells during Wallerian degeneration is Ca(2+)-dependent, and that it induces ATP release from Schwann cells.
Collapse
Affiliation(s)
- Youn Ho Shin
- Department of Anatomy, College of Medicine, Kyung Hee University, Heogi-Dong 1, Dongdaemun-Gu, Seoul 130-701, Republic of Korea
| | | | | |
Collapse
|
99
|
Becherer U, Medart MR, Schirra C, Krause E, Stevens D, Rettig J. Regulated exocytosis in chromaffin cells and cytotoxic T lymphocytes: How similar are they? Cell Calcium 2012; 52:303-12. [DOI: 10.1016/j.ceca.2012.04.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 03/27/2012] [Accepted: 04/09/2012] [Indexed: 10/28/2022]
|
100
|
Li X, Gulbins E, Zhang Y. Oxidative stress triggers Ca-dependent lysosome trafficking and activation of acid sphingomyelinase. Cell Physiol Biochem 2012; 30:815-26. [PMID: 22890197 PMCID: PMC3777434 DOI: 10.1159/000341460] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2012] [Indexed: 12/27/2022] Open
Abstract
Recent studies demonstrate that rapid translocation of the acid sphingomyelinase (ASM), a lysosomal hydrolase, to the outer leaflet of the cell membrane and concomitant release of ceramide constitute a common cellular signaling cascade to various stimuli including CD95 ligation, UV-irradiation, bacterial and viral infections. Reactive oxygen species (ROS) were shown to play a crucial role in regulating this signaling cascade at least for some bacterial infections and UV-irradiation. However, the precise role of ROS for regulation of ASM is unknown. Here, by confocal microscopy and flow cytometry analysis, we demonstrate that hydrogen peroxide (H(2)O(2)), a primary form of ROS in mammalian cells, induces very rapid translocation of ASM and formation of ceramide-enriched membrane platforms in the plasma membrane of Jurkat T cells. In parallel, H(2)O(2) triggers lysosome trafficking and fusion with the plasma membrane, i.e. lysosome exocytosis, as detected by exposure of a lysosome-associated protein, LAMP1. Depletion of intracellular Ca(2+) by cell permeable EGTA-AM inhibits H(2)O(2)-induced lysosome exocytosis, ASM translocation and formation of ceramide-enriched platforms. Pharmacological inhibition or genetic deficiency of ASM did not affect H(2)O(2)-induced lysosome exocytosis. These results indicate that ROS-induced membrane translocation of ASM is mediated by exocytosis of lysosomes, which is dependent on intracellular Ca(2+) release.
Collapse
Affiliation(s)
- Xiang Li
- Department of Pharmacology & Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, U.S.A
| | - Erich Gulbins
- Institute of Molecular Biology, University of Duisburg-Essen, Hufelandstr. 55, Essen, Germany
| | - Yang Zhang
- Department of Pharmacology & Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, U.S.A
| |
Collapse
|