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Xu J, Song Y, Ding S, Duan W, Xiang G, Wang Z. Myeloid-derived growth factor and its effects on cardiovascular and metabolic diseases. Cytokine Growth Factor Rev 2024; 76:77-85. [PMID: 38185568 DOI: 10.1016/j.cytogfr.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 12/28/2023] [Indexed: 01/09/2024]
Abstract
Myeloid-derived growth factor (MYDGF) is a paracrine protein produced by bone marrow-derived monocytes and macrophages. Current research shows that it has protective effects on the cardiovascular system, such as repairing heart tissue after myocardial infarction, enhancing cardiomyocyte proliferation, improving cardiac regeneration after myocardial injury, regulating proliferation and survival of endothelial cells, reducing endothelial cell damage, resisting pressure overload-induced heart failure, as well as protecting against atherosclerosis. Furthermore, regarding the metabolic diseases, MYDGF has effects of improving type 2 diabetes mellitus, relieving non-alcoholic fatty liver disease, alleviating glomerular diseases, and resisting osteoporosis. Herein, we will discuss the biology of MYDGF and its effects on cardiovascular and metabolic diseases.
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Affiliation(s)
- Jinling Xu
- Department of Endocrinology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, China
| | - Yanzhuo Song
- Nanchang University, Nanchang, Jiangxi 330031, China
| | - Sheng Ding
- Department of Endocrinology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, China
| | - Weizhe Duan
- Department of Endocrinology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, China
| | - Guangda Xiang
- Department of Endocrinology, General Hospital of Central Theater Command, Wuluo Road 627, Wuhan, Hubei 430070, China.
| | - Zhongjing Wang
- Department of Endocrinology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, China.
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2
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Chamberlain N, Anathy V. Pathological consequences of the unfolded protein response and downstream protein disulphide isomerases in pulmonary viral infection and disease. J Biochem 2020; 167:173-184. [PMID: 31790139 PMCID: PMC6988748 DOI: 10.1093/jb/mvz101] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 11/08/2019] [Indexed: 12/15/2022] Open
Abstract
Protein folding within the endoplasmic reticulum (ER) exists in a delicate balance; perturbations of this balance can overload the folding capacity of the ER and disruptions of ER homoeostasis is implicated in numerous diseases. The unfolded protein response (UPR), a complex adaptive stress response, attempts to restore normal proteostasis, in part, through the up-regulation of various foldases and chaperone proteins including redox-active protein disulphide isomerases (PDIs). There are currently over 20 members of the PDI family each consisting of varying numbers of thioredoxin-like domains which, generally, assist in oxidative folding and disulphide bond rearrangement of peptides. While there is a large amount of redundancy in client proteins of the various PDIs, the size of the family would indicate more nuanced roles for the individual PDIs. However, the role of individual PDIs in disease pathogenesis remains uncertain. The following review briefly discusses recent findings of ER stress, the UPR and the role of individual PDIs in various respiratory disease states.
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Affiliation(s)
- Nicolas Chamberlain
- Department of Pathology and Laboratory Medicine, University of Vermont Larner College of Medicine, 149 Beaumont Ave, Burlington, VT 05405, USA
| | - Vikas Anathy
- Department of Pathology and Laboratory Medicine, University of Vermont Larner College of Medicine, 149 Beaumont Ave, Burlington, VT 05405, USA
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3
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Chamberlain N, Korwin-Mihavics BR, Nakada EM, Bruno SR, Heppner DE, Chapman DG, Hoffman SM, van der Vliet A, Suratt BT, Dienz O, Alcorn JF, Anathy V. Lung epithelial protein disulfide isomerase A3 (PDIA3) plays an important role in influenza infection, inflammation, and airway mechanics. Redox Biol 2019; 22:101129. [PMID: 30735910 PMCID: PMC6365984 DOI: 10.1016/j.redox.2019.101129] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/24/2019] [Accepted: 01/28/2019] [Indexed: 11/18/2022] Open
Abstract
Protein disulfide isomerases (PDI) are a family of redox chaperones that catalyze formation or isomerization of disulfide bonds in proteins. Previous studies have shown that one member, PDIA3, interacts with influenza A virus (IAV) hemagglutinin (HA), and this interaction is required for efficient oxidative folding of HA in vitro. However, it is unknown whether these host-viral protein interactions occur during active infection and whether such interactions represent a putative target for the treatment of influenza infection. Here we show that PDIA3 is specifically upregulated in IAV-infected mouse or human lung epithelial cells and PDIA3 directly interacts with IAV-HA. Treatment with a PDI inhibitor, LOC14 inhibited PDIA3 activity in lung epithelial cells, decreased intramolecular disulfide bonds and subsequent oligomerization (maturation) of HA in both H1N1 (A/PR8/34) and H3N2 (X31, A/Aichi/68) infected lung epithelial cells. These reduced disulfide bond formation significantly decreased viral burden, and also pro-inflammatory responses from lung epithelial cells. Lung epithelial-specific deletion of PDIA3 in mice resulted in a significant decrease in viral burden and lung inflammatory-immune markers upon IAV infection, as well as significantly improved airway mechanics. Taken together, these results indicate that PDIA3 is required for effective influenza pathogenesis in vivo, and pharmacological inhibition of PDIs represents a promising new anti-influenza therapeutic strategy during pandemic and severe influenza seasons.
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Affiliation(s)
- Nicolas Chamberlain
- Department of Pathology and Laboratory Medicine, University of Vermont College of Medicine, Burlington, VT, United States
| | - Bethany R Korwin-Mihavics
- Department of Pathology and Laboratory Medicine, University of Vermont College of Medicine, Burlington, VT, United States
| | - Emily M Nakada
- Department of Pathology and Laboratory Medicine, University of Vermont College of Medicine, Burlington, VT, United States
| | - Sierra R Bruno
- Department of Pathology and Laboratory Medicine, University of Vermont College of Medicine, Burlington, VT, United States
| | - David E Heppner
- Department of Pathology and Laboratory Medicine, University of Vermont College of Medicine, Burlington, VT, United States
| | - David G Chapman
- Department of Medicine, University of Vermont College of Medicine, Burlington, VT, United States; Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia; Sydney Medical School, University of Sydney, Sydney, Australia; Translational Airways Group, School of Life Sciences, University of Technology, Sydney, Australia
| | - Sidra M Hoffman
- Department of Pathology and Laboratory Medicine, University of Vermont College of Medicine, Burlington, VT, United States
| | - Albert van der Vliet
- Department of Pathology and Laboratory Medicine, University of Vermont College of Medicine, Burlington, VT, United States
| | - Benjamin T Suratt
- Department of Medicine, University of Vermont College of Medicine, Burlington, VT, United States
| | - Oliver Dienz
- Department of Surgery, University of Vermont College of Medicine, Burlington, VT, United States
| | - John F Alcorn
- Division of Pulmonary Medicine, Allergy, and Immunology, Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh, Pittsburgh, PA, United States
| | - Vikas Anathy
- Department of Pathology and Laboratory Medicine, University of Vermont College of Medicine, Burlington, VT, United States.
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Bortnov V, Annis DS, Fogerty FJ, Barretto KT, Turton KB, Mosher DF. Myeloid-derived growth factor is a resident endoplasmic reticulum protein. J Biol Chem 2018; 293:13166-13175. [PMID: 29954947 DOI: 10.1074/jbc.ac118.002052] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 06/25/2018] [Indexed: 12/22/2022] Open
Abstract
Human myeloid-derived growth factor (MYDGF; also known as C19orf10) is named based on its identification as a secreted monocyte/macrophage-derived mediator of cardiac repair following myocardial infarction in mice. Homologs of MYDGF, however, are present in organisms throughout and outside of the animal kingdom, some of which lack hematopoietic and circulatory systems. Moreover, the UPF0556 protein domain, which defines these homologs, lacks a known structure. As a result, the functions and properties of MYDGF are unclear. Our current work was initiated to test whether MYDGF is present in secretory vesicles of eosinophils as it was recently reported to be abundant in these cells. However, we could not demonstrate secretion and unexpectedly discovered that MYDGF colocalizes with P4HB in the nuclear envelope, which comprises the bulk of endoplasmic reticulum (ER) in eosinophils, and with P4HB and RCAS1 in Golgi. We noted a ubiquitous C-terminal sequence, BXEL (B, basic; X, variable residue; E, Glu; L, Leu), that has the potential to retain human MYDGF and its homologs in the ER. To test the functionality of this sequence, we expressed full-length human MYDGF or MYDGF lacking the C-terminal Glu-Leu residues in monolayers of human embryonic kidney 293 (HEK293) cells. Full-length MYDGF accumulated in cells, whereas truncated MYDGF appeared in the medium. These observations reveal that MYDGF resides in the ER and Golgi and provide a new framework for investigating and understanding this intriguing protein.
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Affiliation(s)
| | | | | | | | | | - Deane F Mosher
- From the Departments of Biomolecular Chemistry and .,Medicine, University of Wisconsin, Madison, Wisconsin 53706
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5
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Melo RCN, Weller PF. Contemporary understanding of the secretory granules in human eosinophils. J Leukoc Biol 2018; 104:85-93. [PMID: 29749658 DOI: 10.1002/jlb.3mr1217-476r] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 02/14/2018] [Accepted: 02/16/2018] [Indexed: 12/12/2022] Open
Abstract
Eosinophil secretory (specific) granules have a unique morphology and are both a morphologic hallmark of eosinophils and fundamental to eosinophil-mediated responses. Eosinophil mediators with multiple functional activities are presynthesized and stored within these granules, poised for very rapid, stimulus-induced secretion. The structural organization and changes of eosinophil specific granules are revealing in demonstrating the complex and diverse secretory activities of this cell. Here, we review our current knowledge on the architecture, composition, and function of eosinophil specific granules as highly elaborated organelles able to produce vesiculotubular carriers and to interplay with the intracellular vesicular trafficking. We reconsider prior identifications of eosinophil cytoplasmic granules, including "primary," "secondary," "microgranules," and "small granules"; and consonant with advances, we provide a contemporary recognition that human eosinophils contain a single population of specific granules and their developmental precursors and derived secretory vesicles.
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Affiliation(s)
- Rossana C N Melo
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, UFJF, Rua José Lourenço Kelmer, Juiz de Fora, Brazil.,Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Peter F Weller
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, UFJF, Rua José Lourenço Kelmer, Juiz de Fora, Brazil
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Soares Moretti AI, Martins Laurindo FR. Protein disulfide isomerases: Redox connections in and out of the endoplasmic reticulum. Arch Biochem Biophys 2016; 617:106-119. [PMID: 27889386 DOI: 10.1016/j.abb.2016.11.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/08/2016] [Accepted: 11/21/2016] [Indexed: 12/13/2022]
Abstract
Protein disulfide isomerases are thiol oxidoreductase chaperones from thioredoxin superfamily. As redox folding catalysts from the endoplasmic reticulum (ER), their roles in ER-related redox homeostasis and signaling are well-studied. PDIA1 exerts thiol oxidation/reduction and isomerization, plus chaperone effects. Also, substantial evidence indicates that PDIs regulate thiol-disulfide switches in other cell locations such as cell surface and possibly cytosol. Subcellular PDI translocation routes remain unclear and seem Golgi-independent. The list of signaling and structural proteins reportedly regulated by PDIs keeps growing, via thiol switches involving oxidation, reduction and isomerization, S-(de)nytrosylation, (de)glutathyonylation and protein oligomerization. PDIA1 is required for agonist-triggered Nox NADPH oxidase activation and cell migration in vascular cells and macrophages, while PDIA1-dependent cytoskeletal regulation appears a converging pathway. Extracellularly, PDIs crucially regulate thiol redox signaling of thrombosis/platelet activation, e.g., integrins, and PDIA1 supports expansive caliber remodeling during injury repair via matrix/cytoskeletal organization. Some proteins display regulatory PDI-like motifs. PDI effects are orchestrated by expression levels or post-translational modifications. PDI is redox-sensitive, although probably not a mass-effect redox sensor due to kinetic constraints. Rather, the "all-in-one" organization of its peculiar redox/chaperone properties likely provide PDIs with precision and versatility in redox signaling, making them promising therapeutic targets.
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Affiliation(s)
- Ana Iochabel Soares Moretti
- Vascular Biology Laboratory, Heart Institute (InCor), University of São Paulo, School of Medicine, São Paulo, Brazil
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Akuthota P, Carmo LAS, Bonjour K, Murphy RO, Silva TP, Gamalier JP, Capron KL, Tigges J, Toxavidis V, Camacho V, Ghiran I, Ueki S, Weller PF, Melo RCN. Extracellular Microvesicle Production by Human Eosinophils Activated by "Inflammatory" Stimuli. Front Cell Dev Biol 2016; 4:117. [PMID: 27833910 PMCID: PMC5081571 DOI: 10.3389/fcell.2016.00117] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 10/07/2016] [Indexed: 01/08/2023] Open
Abstract
A key function of human eosinophils is to secrete cytokines, chemokines and cationic proteins, trafficking, and releasing these mediators for roles in inflammation and other immune responses. Eosinophil activation leads to secretion of pre-synthesized granule-stored mediators through different mechanisms, but the ability of eosinophils to secrete extracellular vesicles (EVs), very small vesicles with preserved membrane topology, is still poorly understood. In the present work, we sought to identify and characterize EVs released from human eosinophils during different conditions: after a culturing period or after isolation and stimulation with inflammatory stimuli, which are known to induce eosinophil activation and secretion: CCL11 (eotaxin-1) and tumor necrosis factor alpha (TNF-α). EV production was investigated by nanoscale flow cytometry, conventional transmission electron microscopy (TEM) and pre-embedding immunonanogold EM. The tetraspanins CD63 and CD9 were used as EV biomarkers for both flow cytometry and ultrastructural immunolabeling. Nanoscale flow cytometry showed that human eosinophils produce EVs in culture and that a population of EVs expressed detectable CD9, while CD63 was not consistently detected. When eosinophils were stimulated immediately after isolation and analyzed by TEM, EVs were clearly identified as microvesicles (MVs) outwardly budding off the plasma membrane. Both CCL11 and TNF-α induced significant increases of MVs compared to unstimulated cells. TNF-α induced amplified release of MVs more than CCL11. Eosinophil MV diameters varied from 20 to 1000 nm. Immunonanogold EM revealed clear immunolabeling for CD63 and CD9 on eosinophil MVs, although not all MVs were labeled. Altogether, we identified, for the first time, that human eosinophils secrete MVs and that this production increases in response to inflammatory stimuli. This is important to understand the complex secretory activities of eosinophils underlying immune responses. The contribution of the eosinophil-derived MVs to the regulation of immune responses awaits further investigation.
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Affiliation(s)
- Praveen Akuthota
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical SchoolBoston, MA, USA; Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California San DiegoLa Jolla, CA, USA
| | - Lívia A S Carmo
- Laboratory of Cellular Biology, Department of Biology, Institute of Biological Sciences (ICB), Federal University of Juiz de Fora Juiz de Fora, Brazil
| | - Kennedy Bonjour
- Laboratory of Cellular Biology, Department of Biology, Institute of Biological Sciences (ICB), Federal University of Juiz de Fora Juiz de Fora, Brazil
| | - Ryann O Murphy
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, USA
| | - Thiago P Silva
- Laboratory of Cellular Biology, Department of Biology, Institute of Biological Sciences (ICB), Federal University of Juiz de Fora Juiz de Fora, Brazil
| | - Juliana P Gamalier
- Laboratory of Cellular Biology, Department of Biology, Institute of Biological Sciences (ICB), Federal University of Juiz de Fora Juiz de Fora, Brazil
| | - Kelsey L Capron
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, USA
| | - John Tigges
- Flow Cytometry Core, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, USA
| | - Vasilis Toxavidis
- Flow Cytometry Core, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, USA
| | - Virginia Camacho
- Flow Cytometry Core, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, USA
| | - Ionita Ghiran
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, USA
| | - Shigeharu Ueki
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine Akita, Japan
| | - Peter F Weller
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, USA
| | - Rossana C N Melo
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical SchoolBoston, MA, USA; Laboratory of Cellular Biology, Department of Biology, Institute of Biological Sciences (ICB), Federal University of Juiz de ForaJuiz de Fora, Brazil
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Carmo LAS, Bonjour K, Ueki S, Neves JS, Liu L, Spencer LA, Dvorak AM, Weller PF, Melo RCN. CD63 is tightly associated with intracellular, secretory events chaperoning piecemeal degranulation and compound exocytosis in human eosinophils. J Leukoc Biol 2016; 100:391-401. [PMID: 26965633 PMCID: PMC6608091 DOI: 10.1189/jlb.3a1015-480r] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 01/18/2016] [Accepted: 02/02/2016] [Indexed: 12/26/2022] Open
Abstract
Eosinophil activation leads to secretion of presynthesized, granule-stored mediators that determine the course of allergic, inflammatory, and immunoregulatory responses. CD63, a member of the transmembrane-4 glycoprotein superfamily (tetraspanins) and present on the limiting membranes of eosinophil-specific (secretory) granules, is considered a potential surface marker for eosinophil degranulation. However, the intracellular secretory trafficking of CD63 in eosinophils and other leukocytes is not understood. Here, we provide a comprehensive investigation of CD63 trafficking at high resolution within human eosinophils stimulated with inflammatory stimuli, CCL11 and tumor necrosis factor α, which induce distinctly differing secretory processes in eosinophils: piecemeal degranulation and compound exocytosis, respectively. By using different transmission electron microscopy approaches, including an immunonanogold technique, for enhanced detection of CD63 at subcellular compartments, we identified a major intracellular pool of CD63 that is directly linked to eosinophil degranulation events. Transmission electron microscopy quantitative analyses demonstrated that, in response to stimulation, CD63 is concentrated within granules undergoing secretion by piecemeal degranulation or compound exocytosis and that CD63 tracks with the movements of vesicles and granules in the cytoplasm. Although CD63 was observed at the cell surface after stimulation, immunonanogold electron microscopy revealed that a strong CD63 pool remains in the cytoplasm. It is remarkable that CCL11 and tumor necrosis factor α triggered increased formation of CD63(+) large vesiculotubular carriers (eosinophil sombrero vesicles), which fused with granules in the process of secretion, likely acting in the intracellular translocation of CD63. Altogether, we identified active, intracellular CD63 trafficking connected to eosinophil granule-derived secretory pathways. This is important for understanding the complex secretory activities of eosinophils underlying immune responses.
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Affiliation(s)
- Lívia A S Carmo
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, UFJF, Juiz de Fora, Brazil
| | - Kennedy Bonjour
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, UFJF, Juiz de Fora, Brazil
| | - Shigeharu Ueki
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
| | - Josiane S Neves
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Linying Liu
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; and
| | - Lisa A Spencer
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; and
| | - Ann M Dvorak
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Peter F Weller
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; and
| | - Rossana C N Melo
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, UFJF, Juiz de Fora, Brazil; Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; and
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Expression and subcellular localization of the Qa-SNARE syntaxin17 in human eosinophils. Exp Cell Res 2015; 337:129-135. [PMID: 26254897 DOI: 10.1016/j.yexcr.2015.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 06/29/2015] [Accepted: 07/06/2015] [Indexed: 01/21/2023]
Abstract
BACKGROUND SNARE members mediate membrane fusion during intracellular trafficking underlying innate and adaptive immune responses by different cells. However, little is known about the expression and function of these proteins in human eosinophils, cells involved in allergic, inflammatory and immunoregulatory responses. Here, we investigate the expression and distribution of the Qa-SNARE syntaxin17 (STX17) within human eosinophils isolated from the peripheral blood. METHODS Flow cytometry and a pre-embedding immunonanogold electron microscopy (EM) technique that combines optimal epitope preservation and secondary Fab-fragments of antibodies linked to 1.4 nm gold particles for optimal access to microdomains, were used to investigate STX17. RESULTS STX17 was detected within unstimulated eosinophils. Immunogold EM revealed STX17 on secretory granules and on granule-derived vesiculotubular transport carriers (Eosinophil Sombrero Vesicles-EoSVs). Quantitative EM analyses showed that 77.7% of the granules were positive for STX17 with a mean±SEM of 3.9±0.2 gold particles/granule. Labeling was present on both granule outer membranes and matrices while EoSVs showed clear membrane-associated labeling. STX17 was also present in secretory granules in eosinophils stimulated with the cytokine tumor necrosis factor alpha (TNF-α) or the CC-chemokine ligand 11 CCL11 (eotaxin-1), stimuli that induce eosinophil degranulation. The number of secretory granules labeled for STX17 was significantly higher in CCL11 compared with the unstimulated group. The level of cell labeling did not change when unstimulated cells were compared with TNF-α-stimulated eosinophils. CONCLUSIONS The present study clearly shows by immunanonogold EM that STX17 is localized in eosinophil secretory granules and transport vesicles and might be involved in the transport of granule-derived cargos.
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Melo RCN, Morgan E, Monahan-Earley R, Dvorak AM, Weller PF. Pre-embedding immunogold labeling to optimize protein localization at subcellular compartments and membrane microdomains of leukocytes. Nat Protoc 2014; 9:2382-94. [PMID: 25211515 DOI: 10.1038/nprot.2014.163] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Precise immunolocalization of proteins within a cell is central to understanding cell processes and functions such as intracellular trafficking and secretion of molecules during immune responses. Here we describe a protocol for ultrastructural detection of proteins in leukocytes. The method uses a pre-embedding approach (immunolabeling before standard processing for transmission electron microscopy (TEM)). This protocol combines several strategies for ultrastructure and antigen preservation, robust blocking of nonspecific binding sites, as well as superior antibody penetration for detecting molecules at subcellular compartments and membrane microdomains. A further advantage of this technique is that electron microscopy (EM) processing is quick. This method has been used to study leukocyte biology, and it has helped demonstrate how activated leukocytes deliver specific cargos. It may also potentially be applied to a variety of different cell types. Excluding the initial time required for sample preparation (15 h) and the final resin polymerization step (16 h), the protocol (immunolabeling and EM procedures) can be completed in 8 h.
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Affiliation(s)
- Rossana C N Melo
- 1] Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil. [2] Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Ellen Morgan
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Rita Monahan-Earley
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Ann M Dvorak
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Peter F Weller
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
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Melo RCN, Weller PF. Unraveling the complexity of lipid body organelles in human eosinophils. J Leukoc Biol 2014; 96:703-12. [PMID: 25210147 DOI: 10.1189/jlb.3ru0214-110r] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Lipid-rich organelles are common in many cell types. In cells, such as adipocytes, these organelles are termed LDs, whereas in other cells, such as leukocytes, they are called LBs. The study of leukocyte LBs has attracted attention as a result of their association with human diseases. In leukocytes, such as eosinophils, LB accumulation has been documented extensively during inflammatory conditions. In these cells, LBs are linked to the regulation of immune responses by compartmentalization of several proteins and lipids involved in the control and biosynthesis of inflammatory mediators (eicosanoids). However, it has been unclear how diverse proteins, including membrane-associated enzymes involved in eicosanoid formation, incorporate into LBs, especially if the internal content of LBs is assumed to consist solely of stores of neutral lipids, as present within adipocyte LDs. Studies of the formation, function, and ultrastructure of LBs in eosinophils have been providing insights pertinent to LBs in other leukocytes. Here, we review current knowledge of the composition and function of leukocyte LBs as provided by studies of human eosinophil LBs, including recognitions of the internal architecture of eosinophil LBs based on 3D electron tomographic analyses.
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Affiliation(s)
- Rossana C N Melo
- Laboratory of Cellular Biology, Department of Biology, Institute of Biological Sciences, Federal University of Juiz de Fora, Brazil; and Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Peter F Weller
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
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