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Dudka W, Salo VT, Mahamid J. Zooming into lipid droplet biology through the lens of electron microscopy. FEBS Lett 2024; 598:1127-1142. [PMID: 38726814 DOI: 10.1002/1873-3468.14899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/08/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024]
Abstract
Electron microscopy (EM), in its various flavors, has significantly contributed to our understanding of lipid droplets (LD) as central organelles in cellular metabolism. For example, EM has illuminated that LDs, in contrast to all other cellular organelles, are uniquely enclosed by a single phospholipid monolayer, revealed the architecture of LD contact sites with different organelles, and provided near-atomic resolution maps of key enzymes that regulate neutral lipid biosynthesis and LD biogenesis. In this review, we first provide a brief history of pivotal findings in LD biology unveiled through the lens of an electron microscope. We describe the main EM techniques used in the context of LD research and discuss their current capabilities and limitations, thereby providing a foundation for utilizing suitable EM methodology to address LD-related questions with sufficient level of structural preservation, detail, and resolution. Finally, we highlight examples where EM has recently been and is expected to be instrumental in expanding the frontiers of LD biology.
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Affiliation(s)
- Wioleta Dudka
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Veijo T Salo
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Cell Biology and Biophysics Unit, EMBL, Heidelberg, Germany
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2
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Bonjour K, Palazzi C, Silva TP, Malta KK, Neves VH, Oliveira-Barros EG, Neves I, Kersten VA, Fortuna BT, Samarasinghe AE, Weller PF, Bandeira-Melo C, Melo RCN. Mitochondrial Population in Mouse Eosinophils: Ultrastructural Dynamics in Cell Differentiation and Inflammatory Diseases. Front Cell Dev Biol 2022; 10:836755. [PMID: 35386204 PMCID: PMC8979069 DOI: 10.3389/fcell.2022.836755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/25/2022] [Indexed: 12/20/2022] Open
Abstract
Mitochondria are multifunctional organelles of which ultrastructure is tightly linked to cell physiology. Accumulating evidence shows that mitochondrial remodeling has an impact on immune responses, but our current understanding of the mitochondrial architecture, interactions, and morphological changes in immune cells, mainly in eosinophils, is still poorly known. Here, we applied transmission electron microscopy (TEM), single-cell imaging analysis, and electron tomography, a technique that provides three-dimensional (3D) views at high resolution, to investigate mitochondrial dynamics in mouse eosinophils developing in cultures as well as in the context of inflammatory diseases characterized by recruitment and activation of these cells (mouse models of asthma, H1N1 influenza A virus (IAV) infection, and schistosomiasis mansoni). First, quantitative analyses showed that the mitochondrial area decrease 70% during eosinophil development (from undifferentiated precursor cells to mature eosinophils). Mitophagy, a consistent process revealed by TEM in immature but not in mature eosinophils, is likely operating in mitochondrial clearance during eosinophilopoiesis. Events of mitochondria interaction (inter-organelle membrane contacts) were also detected and quantitated within developing eosinophils and included mitochondria-endoplasmic reticulum, mitochondria-mitochondria, and mitochondria-secretory granules, all of them significantly higher in numbers in immature compared to mature cells. Moreover, single-mitochondrion analyses revealed that as the eosinophil matures, mitochondria cristae significantly increase in number and reshape to lamellar morphology. Eosinophils did not change (asthma) or reduced (IAV and Schistosoma infections) their mitochondrial mass in response to inflammatory diseases. However, asthma and schistosomiasis, but not IAV infection, induced amplification of both cristae numbers and volume in individual mitochondria. Mitochondrial cristae remodeling occurred in all inflammatory conditions with the proportions of mitochondria containing only lamellar or tubular, or mixed cristae (an ultrastructural aspect seen just in tissue eosinophils) depending on the tissue/disease microenvironment. The ability of mitochondria to interact with granules, mainly mobilized ones, was remarkably captured by TEM in eosinophils participating in all inflammatory diseases. Altogether, we demonstrate that the processes of eosinophilopoiesis and inflammation-induced activation interfere with the mitochondrial dynamics within mouse eosinophils leading to cristae remodeling and inter-organelle contacts. The understanding of how mitochondrial dynamics contribute to eosinophil immune functions is an open interesting field to be explored.
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Affiliation(s)
- Kennedy Bonjour
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, Rua José Lourenço Kelmer, Juiz de Fora, Brazil
| | - Cinthia Palazzi
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, Rua José Lourenço Kelmer, Juiz de Fora, Brazil
| | - Thiago P Silva
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, Rua José Lourenço Kelmer, Juiz de Fora, Brazil
| | - Kássia K Malta
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, Rua José Lourenço Kelmer, Juiz de Fora, Brazil
| | - Vitor H Neves
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, Rua José Lourenço Kelmer, Juiz de Fora, Brazil
| | - Eliane G Oliveira-Barros
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, Rua José Lourenço Kelmer, Juiz de Fora, Brazil
| | - Igor Neves
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, Rua José Lourenço Kelmer, Juiz de Fora, Brazil
| | - Victor A Kersten
- Laboratory of Inflammation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bruno T Fortuna
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, Rua José Lourenço Kelmer, Juiz de Fora, Brazil
| | - Amali E Samarasinghe
- Division of Pulmonology, Allergy-Immunology and Sleep, Department of Pediatrics, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Peter F Weller
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Christianne Bandeira-Melo
- Laboratory of Inflammation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rossana C N Melo
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, Rua José Lourenço Kelmer, Juiz de Fora, Brazil.,Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
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Pereira-Dutra FS, Bozza PT. Lipid droplets diversity and functions in inflammation and immune response. Expert Rev Proteomics 2021; 18:809-825. [PMID: 34668810 DOI: 10.1080/14789450.2021.1995356] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Lipid droplets (LDs) are dynamic and evolutionary conserved lipid-enriched organelles composed of a core of neutral lipids surrounded by a monolayer of phospholipids associated with a diverse array of proteins that are cell- and stimulus-regulated. Far beyond being simply a deposit of neutral lipids, accumulating evidence demonstrate that LDs act as spatial and temporal local for lipid and protein compartmentalization and signaling organization. AREAS COVERED This review focuses on the progress in our understanding of LD protein diversity and LD functions in the context of cell signaling and immune responses, highlighting the relationship between LD composition with the multiple roles of this organelle in immunometabolism, inflammation and host-response to infection. EXPERT OPINION LDs are essential platforms for various cellular processes, including metabolic regulation, cell signaling, and immune responses. The functions of LD in infection and inflammatory disease are associated with the dynamic and complexity of their proteome. Our contemporary view place LDs as critical regulators of different inflammatory and infectious diseases and key markers of leukocyte activation.
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Affiliation(s)
- Filipe S Pereira-Dutra
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Patrícia T Bozza
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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Pereira-Dutra FS, Teixeira L, de Souza Costa MF, Bozza PT. Fat, fight, and beyond: The multiple roles of lipid droplets in infections and inflammation. J Leukoc Biol 2019; 106:563-580. [PMID: 31121077 DOI: 10.1002/jlb.4mr0119-035r] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 04/16/2019] [Accepted: 04/26/2019] [Indexed: 12/12/2022] Open
Abstract
Increased accumulation of cytoplasmic lipid droplets (LDs) in host nonadipose cells is commonly observed in response to numerous infectious diseases, including bacterial, parasite, and fungal infections. LDs are lipid-enriched, dynamic organelles composed of a core of neutral lipids surrounded by a monolayer of phospholipids associated with a diverse array of proteins that are cell and stimulus regulated. Far beyond being simply a deposit of neutral lipids, LDs have come to be seen as an essential platform for various cellular processes, including metabolic regulation, cell signaling, and the immune response. LD participation in the immune response occurs as sites for compartmentalization of several immunometabolic signaling pathways, production of inflammatory lipid mediators, and regulation of antigen presentation. Infection-driven LD biogenesis is a complexly regulated process that involves innate immune receptors, transcriptional and posttranscriptional regulation, increased lipid uptake, and new lipid synthesis. Accumulating evidence demonstrates that intracellular pathogens are able to exploit LDs as an energy source, a replication site, and/or a mechanism of immune response evasion. Nevertheless, LDs can also act in favor of the host as part of the immune and inflammatory response to pathogens. Here, we review recent findings that explored the new roles of LDs in the context of host-pathogen interactions.
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Affiliation(s)
- Filipe S Pereira-Dutra
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Livia Teixeira
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | | | - Patrícia T Bozza
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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Vallochi AL, Teixeira L, Oliveira KDS, Maya-Monteiro CM, Bozza PT. Lipid Droplet, a Key Player in Host-Parasite Interactions. Front Immunol 2018; 9:1022. [PMID: 29875768 PMCID: PMC5974170 DOI: 10.3389/fimmu.2018.01022] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/24/2018] [Indexed: 12/18/2022] Open
Abstract
Lipid droplets (lipid bodies, LDs) are dynamic organelles that have important roles in regulating lipid metabolism, energy homeostasis, cell signaling, membrane trafficking, and inflammation. LD biogenesis, composition, and functions are highly regulated and may vary according to the stimuli, cell type, activation state, and inflammatory environment. Increased cytoplasmic LDs are frequently observed in leukocytes and other cells in a number of infectious diseases. Accumulating evidence reveals LDs participation in fundamental mechanisms of host-pathogen interactions, including cell signaling and immunity. LDs are sources of eicosanoid production, and may participate in different aspects of innate signaling and antigen presentation. In addition, intracellular pathogens evolved mechanisms to subvert host metabolism and may use host LDs, as ways of immune evasion and nutrients source. Here, we review mechanisms of LDs biogenesis and their contributions to the infection progress, and discuss the latest discoveries on mechanisms and pathways involving LDs roles as regulators of the immune response to protozoan infection.
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Affiliation(s)
- Adriana Lima Vallochi
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| | | | | | | | - Patricia T. Bozza
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
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Amaral KB, Silva TP, Malta KK, Carmo LAS, Dias FF, Almeida MR, Andrade GFS, Martins JS, Pinho RR, Costa-Neto SF, Gentile R, Melo RCN. Natural Schistosoma mansoni Infection in the Wild Reservoir Nectomys squamipes Leads to Excessive Lipid Droplet Accumulation in Hepatocytes in the Absence of Liver Functional Impairment. PLoS One 2016; 11:e0166979. [PMID: 27880808 PMCID: PMC5120838 DOI: 10.1371/journal.pone.0166979] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 11/07/2016] [Indexed: 01/06/2023] Open
Abstract
Schistosomiasis is a neglected tropical disease of a significant public health impact. The water rat Nectomys squamipes is one of the most important non-human hosts in the schistosomiasis mansoni transmission in Brazil, being considered a wild reservoir. Cellular mechanisms that contribute to the physiological adaptation of this rodent to the Schistosoma mansoni parasite are poorly understood. Here we identified, for the first time, that a hepatic steatosis, a condition characterized by excessive lipid accumulation with formation of lipid droplets (LDs) within hepatocytes, occurs in response to the natural S. mansoni infection of N. squamipes, captured in an endemic region. Significant increases of LD area in the hepatic tissue and LD numbers/hepatocyte, detected by quantitative histopathological and ultrastructural analyses, were paralleled by increased serum profile (total cholesterol and triglycerides) in infected compared to uninfected animals. Raman spectroscopy showed high content of polyunsaturated fatty acids (PUFAs) in the liver of both groups. MALDI-TOFF mass spectroscopy revealed an amplified pool of omega-6 PUFA arachidonic acid in the liver of infected animals. Assessment of liver functional activity by the levels of hepatic transaminases (ALT and AST) did not detect any alteration during the natural infection. In summary, this work demonstrates that the natural infection of the wild reservoir N. squamipes with S. mansoni elicits hepatic steatosis in the absence of liver functional harm and that accumulation of lipids, markedly PUFAs, coexists with low occurrence of inflammatory granulomatous processes, suggesting that lipid stores may be acting as a protective mechanism for dealing with the infection.
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Affiliation(s)
- Kátia B. Amaral
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036–900
| | - Thiago P. Silva
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036–900
| | - Kássia K. Malta
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036–900
| | - Lívia A. S. Carmo
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036–900
| | - Felipe F. Dias
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036–900
| | - Mariana R. Almeida
- Laboratory of Plasmonic Nanostructures, Molecular Spectroscopy and Structure Group, Department of Chemistry, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036–900
| | - Gustavo F. S. Andrade
- Laboratory of Plasmonic Nanostructures, Molecular Spectroscopy and Structure Group, Department of Chemistry, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036–900
| | - Jefferson S. Martins
- Department of Physics, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036–900
| | - Roberto R. Pinho
- Department of Physics, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036–900
| | - Sócrates F. Costa-Neto
- Laboratory of Biology and Parasitology of Wild Reservoir Mammals, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Rosana Gentile
- Laboratory of Biology and Parasitology of Wild Reservoir Mammals, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Rossana C. N. Melo
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, 36036–900
- * E-mail:
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7
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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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Chen HY, Chiang DML, Lin ZJ, Hsieh CC, Yin GC, Weng IC, Guttmann P, Werner S, Henzler K, Schneider G, Lai LJ, Liu FT. Nanoimaging granule dynamics and subcellular structures in activated mast cells using soft X-ray tomography. Sci Rep 2016; 6:34879. [PMID: 27748356 PMCID: PMC5066221 DOI: 10.1038/srep34879] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 09/19/2016] [Indexed: 12/31/2022] Open
Abstract
Mast cells play an important role in allergic responses. During activation, these cells undergo degranulation, a process by which various kinds of mediators stored in the granules are released. Granule homeostasis in mast cells has mainly been studied by electron microscopy (EM), where the fine structures of subcellular organelles are partially destroyed during sample preparation. Migration and fusion of granules have not been studied in detail in three dimensions (3D) in unmodified samples. Here, we utilized soft X-ray tomography (SXT) coupled with fluorescence microscopy to study the detailed structures of organelles during mast cell activation. We observed granule fission, granule fusion to plasma membranes, and small vesicles budding from granules. We also detected lipid droplets, which became larger and more numerous as mast cells were activated. We observed dramatic morphological changes of mitochondria in activated mast cells and 3D-reconstruction revealed the highly folded cristae inner membrane, features of functionally active mitochondria. We also observed giant vesicles containing granules, mitochondria, and lipid droplets, which we designated as granule-containing vesicles (GCVs) and verified their presence by EM in samples prepared by cryo-substitution, albeit with a less clear morphology. Thus, our studies using SXT provide significant insights into mast cell activation at the organelle level.
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Affiliation(s)
- Huan-Yuan Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, ROC
| | | | - Zi-Jing Lin
- National Synchrotron Radiation Research Center, Taiwan, ROC
| | | | - Gung-Chian Yin
- National Synchrotron Radiation Research Center, Taiwan, ROC
| | - I-Chun Weng
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, ROC
| | - Peter Guttmann
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, D-12489 Berlin, Germany
| | - Stephan Werner
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, D-12489 Berlin, Germany
| | - Katja Henzler
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, D-12489 Berlin, Germany
| | - Gerd Schneider
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, D-12489 Berlin, Germany.,Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin, Germany
| | - Lee-Jene Lai
- National Synchrotron Radiation Research Center, Taiwan, ROC
| | - Fu-Tong Liu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, ROC.,Department of Dermatology, UC Davis School of Medicine, Sacramento, CA, USA
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Khanthusaeng V, Thammasiri J, Bass CS, Navanukraw C, Borowicz P, Redmer DA, Grazul-Bilska AT. Lipid droplets in cultured luteal cells in non-pregnant sheep fed different planes of nutrition. Acta Histochem 2016; 118:553-559. [PMID: 27388430 DOI: 10.1016/j.acthis.2016.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/04/2016] [Accepted: 05/23/2016] [Indexed: 12/31/2022]
Abstract
Accumulation of lipid droplets (LD) in luteal cells likely is important for energy storage and steroidogenesis in the highly metabolically active corpus luteum (CL). The objective of this study was to determine the effect of plane of nutrition on progesterone (P4) secretion, and lipid droplet number and size in cultured ovine luteal cells. Ewes were randomly assigned to one of three nutritional groups: control (C; 100% NRC requirements, n=9), overfed (O; 2×C, n=12), or underfed (U; 0.6×C, n=10). Superovulation was induced by follicle stimulating hormone injections. At the early and mid-luteal phases of the estrous cycle, CL were dissected from ovaries, and luteal cells isolated enzymatically. Luteal cells were incubated overnight in medium containing serum in chamber slides. Media were then changed to serum-free and after 24h incubation, media were collected for P4 analysis, and cells were fixed in formalin and stained with BODIPY followed by DAPI staining. Z-stacks of optical sections of large and small luteal cells (LLC and SLC, respectively) were obtained using a laser-scanning microscope. Rendered 3D images of individual LLC and SLC were analyzed for cell volume, and total and individual LD volume, number and percentage of cellular volume occupied by LD by using Imaris software. Concentrations of P4 in serum and media were greater (P<0.05) at the mid than early-luteal phase, and were not affected by nutritional plane. LD total volume and number were greater (P<0.001) in LLC than SLC; however, mean volume of individual LD was greater (P<0.02) in SLC than LLC. In LLC, total LD volume was greater (P<0.02) in O than C and U ewes. In SLC, total LD volume and number was greater (P<0.003) at the mid than early-luteal phase, and percentage of cell volume occupied by LD was greater (P<0.002) in U than C and O ewes. These data demonstrate that both stage of luteal development and nutritional plane affect selected LD measurements and thus may affect luteal functions. Furthermore, these data confirm that LD dynamics differ among parenchymal steroidogenic luteal cell types.
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Majzner K, Chlopicki S, Baranska M. Lipid droplets formation in human endothelial cells in response to polyunsaturated fatty acids and 1-methyl-nicotinamide (MNA); confocal Raman imaging and fluorescence microscopy studies. JOURNAL OF BIOPHOTONICS 2016; 9:396-405. [PMID: 25966299 DOI: 10.1002/jbio.201500134] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 03/06/2015] [Accepted: 04/07/2015] [Indexed: 06/04/2023]
Abstract
In this work the formation of lipid droplets (LDs) in human endothelial cells culture in response to the uptake of polyunsaturated fatty acids (PUFAs) was studied. Additionally, an effect of 1-methylnicotinamide (MNA) on the process of LDs formation was investigated. LDs have been previously described structurally and to some degree biochemically, however neither the precise function of LDs nor the factors responsible for LD induction have been clarified. Lipid droplets, sometimes referred in the literature as lipid bodies are organelles known to regulate neutrophil, eosinophil, or tumor cell functions but their presence and function in the endothelium is largely unexplored. 3D linear Raman spectroscopy was used to study LDs formation in vitro in a single endothelial cell. The method provides information about distribution and size of LDs as well as their composition. The incubation of endothelial cells with various PUFAs resulted in formation of LDs. As a complementary method for LDs identification a fluorescence microscopy was applied. Fluorescence measurements confirmed the Raman results suggesting endothelial cells uptake of PUFAs and subsequent LDs formation in the cytoplasm of the endothelium. Furthermore, MNA seem to potentiate intracellular uptake of PUFAs to the endothelium that may bear physiological and pharmacological significance. Confocal Raman imaging of HAoEC cell with LDs.
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Affiliation(s)
- Katarzyna Majzner
- Jagiellonian Centre for Experimental Therapeutics (JCET), Jagiellonian University, Bobrzynskiego 14, 30-348, Krakow, Poland
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060, Krakow, Poland
| | - Stefan Chlopicki
- Jagiellonian Centre for Experimental Therapeutics (JCET), Jagiellonian University, Bobrzynskiego 14, 30-348, Krakow, Poland.
- Department of Experimental Pharmacology, Chair of Pharmacology, Jagiellonian University, Grzegorzecka 16, 31-531, Krakow, Poland.
| | - Malgorzata Baranska
- Jagiellonian Centre for Experimental Therapeutics (JCET), Jagiellonian University, Bobrzynskiego 14, 30-348, Krakow, Poland.
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060, Krakow, Poland.
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11
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Melo RCN, Weller PF. Lipid droplets in leukocytes: Organelles linked to inflammatory responses. Exp Cell Res 2015; 340:193-7. [PMID: 26515551 DOI: 10.1016/j.yexcr.2015.10.028] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/23/2015] [Indexed: 01/21/2023]
Abstract
Studies on lipid droplets (LDs) in leukocytes have attracted attention due to their association with human diseases. In these cells, LDs are rapidly formed in response to inflammatory stimuli or allergic/inflammatory diseases including infections with parasites and bacteria. Leukocyte LDs 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). In this mini review, we summarize current knowledge on the composition, structure and function of leukocyte LDs, organelles now considered as structural markers of inflammation.
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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, MG 36036-900, Brazil; Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, CLS 943, Boston, MA 02215, USA.
| | - Peter F Weller
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, CLS 943, Boston, MA 02215, USA.
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12
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Greineisen WE, Maaetoft-Udsen K, Speck M, Balajadia J, Shimoda LMN, Sung C, Turner H. Chronic Insulin Exposure Induces ER Stress and Lipid Body Accumulation in Mast Cells at the Expense of Their Secretory Degranulation Response. PLoS One 2015; 10:e0130198. [PMID: 26263026 PMCID: PMC4532411 DOI: 10.1371/journal.pone.0130198] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 05/17/2015] [Indexed: 12/11/2022] Open
Abstract
Lipid bodies (LB) are reservoirs of precursors to inflammatory lipid mediators in immunocytes, including mast cells. LB numbers are dynamic, increasing dramatically under conditions of immunological challenge. We have previously shown in vitro that insulin-influenced lipogenic pathways induce LB biogenesis in mast cells, with their numbers attaining steatosis-like levels. Here, we demonstrate that in vivo hyperinsulinemia resulting from high fat diet is associated with LB accumulation in murine mast cells and basophils. We characterize the lipidome of purified insulin-induced LB, and the shifts in the whole cell lipid landscape in LB that are associated with their accumulation, in both model (RBL2H3) and primary mast cells. Lipidomic analysis suggests a gain of function associated with LB accumulation, in terms of elevated levels of eicosanoid precursors that translate to enhanced antigen-induced LTC4 release. Loss-of-function in terms of a suppressed degranulation response was also associated with LB accumulation, as were ER reprogramming and ER stress, analogous to observations in the obese hepatocyte and adipocyte. Taken together, these data suggest that chronic insulin elevation drives mast cell LB enrichment in vitro and in vivo, with associated effects on the cellular lipidome, ER status and pro-inflammatory responses.
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Affiliation(s)
- William E. Greineisen
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, Hawaii, United States of America
| | - Kristina Maaetoft-Udsen
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, Hawaii, United States of America
| | - Mark Speck
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, Hawaii, United States of America
| | - Januaria Balajadia
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, Hawaii, United States of America
| | - Lori M. N. Shimoda
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, Hawaii, United States of America
| | - Carl Sung
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, Hawaii, United States of America
| | - Helen Turner
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, Hawaii, United States of America
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, United States of America
- * E-mail:
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13
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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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14
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Maaetoft-Udsen K, Greineisen WE, Aldan JT, Magaoay H, Ligohr C, Shimoda LMN, Sung C, Turner H. Comparative analysis of lipotoxicity induced by endocrine, pharmacological, and innate immune stimuli in rat basophilic leukemia cells. J Immunotoxicol 2014; 12:385-94. [PMID: 25539471 DOI: 10.3109/1547691x.2014.990655] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cellular lipotoxicity manifests as the steatotic accumulation of lipid droplets or lipid bodies, and/or induction of phospholipidosis. Lipotoxicity can be induced by hyperinsulinemia/nutrient overload, cationic amphiphilic drugs (CAD), and innate immunological stimuli, all of which are stimuli relevant to mast cell physiology. Hyper-accumulation of mast cell lipid bodies in response to hyperinsulinemia has been documented, but lipotoxicity in response to CAD or innate immunologic stimuli has not been analysed comparatively. Moreover, gaps in our understanding of this steatosis remain, specifically as to whether hyperinsulinemia-driven steatosis in these cells attains lipotoxic levels or is accompanied by phospholipidosis. To compare endocrine, pharmacological, and innate immunological stimuli for their ability to induce steatosis and phospholipidosis in a rat basophilic leukemia mast cell model (RBL2H3), differential fluorescence microscopy staining and quantitation of phospholipidosis and steatosis in the RBL2H3 cell line was examined. The three classes of stimuli differentially induced phospholipidosis and steatosis. PPARγ up-regulation was not uniformly associated with the expansion of the lipid body population. Fluorescence imaging of lipid-enriched structures generated in response to lipotoxic cationic amphiphilic drugs, chronic insulin exposure, and TLR2/4 ligands revealed differential staining patterns when visualized using lipophilic dyes. It is concluded that lipotoxicity-inducing pathways in this model mast cell system are diverse, and include steatotic responses to an endocrine stimulus, as well as phospholipidosis responses to cationic lipophilic drugs not previously described in this cell type.
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15
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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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16
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Abstract
Eosinophils are multifunctional granular leukocytes that are implicated in the pathogenesis of a wide variety of disorders, including asthma, helminth infection, and rare hypereosinophilic syndromes. Although peripheral and tissue eosinophilia can be a feature of many types of small-vessel and medium-vessel vasculitis, the role of eosinophils has been best studied in eosinophilic granulomatosis with polyangiitis (EGPA), where eosinophils are a characteristic finding in all three clinical stages of the disorder. Whereas numerous studies have demonstrated an association between the presence of eosinophils and markers of eosinophil activation in the blood and tissues of patients with EGPA, the precise role of eosinophils in disease pathogenesis has been difficult to ascertain owing to the complexity of the disease process. In this regard, results of clinical trials using novel agents that specifically target eosinophils are providing the first direct evidence of a central role of eosinophils in EGPA. This Review focuses on the aspects of eosinophil biology most relevant to the pathogenesis of vasculitis and provides an update of current knowledge regarding the role of eosinophils in EGPA and other vasculitides.
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17
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Greineisen WE, Speck M, Shimoda LMN, Sung C, Phan N, Maaetoft-Udsen K, Stokes AJ, Turner H. Lipid body accumulation alters calcium signaling dynamics in immune cells. Cell Calcium 2014; 56:169-80. [PMID: 25016314 DOI: 10.1016/j.ceca.2014.06.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 06/17/2014] [Accepted: 06/18/2014] [Indexed: 10/25/2022]
Abstract
There is well-established variability in the numbers of lipid bodies (LB) in macrophages, eosinophils, and neutrophils. Similarly to the steatosis observed in adipocytes and hepatocytes during hyperinsulinemia and nutrient overload, immune cell LB hyper-accumulate in response to bacterial and parasitic infection and inflammatory presentations. Recently we described that hyperinsulinemia, both in vitro and in vivo, drives steatosis and phenotypic changes in primary and transformed mast cells and basophils. LB reach high numbers in these steatotic cytosols, and here we propose that they could dramatically impact the transcytoplasmic signaling pathways. We compared calcium release and influx responses at the population and single cell level in normal and steatotic model mast cells. At the population level, all aspects of FcɛRI-dependent calcium mobilization, as well as activation of calcium-dependent downstream signaling targets such as NFATC1 phosphorylation are suppressed. At the single cell level, we demonstrate that LB are both sources and sinks of calcium following FcɛRI cross-linking. Unbiased analysis of the impact of the presence of LB on the rate of trans-cytoplasmic calcium signals suggest that LB enrichment accelerates calcium propagation, which may reflect a Bernoulli effect. LB abundance thus impacts this fundamental signaling pathway and its downstream targets.
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Affiliation(s)
- William E Greineisen
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, HI, United States
| | - Mark Speck
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, HI, United States
| | - Lori M N Shimoda
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, HI, United States
| | - Carl Sung
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, HI, United States
| | - Nolwenn Phan
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, HI, United States
| | - Kristina Maaetoft-Udsen
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, HI, United States
| | - Alexander J Stokes
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, United States
| | - Helen Turner
- Laboratory of Immunology and Signal Transduction, Chaminade University, Honolulu, HI, United States; Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, United States.
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18
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Majzner K, Kochan K, Kachamakova-Trojanowska N, Maslak E, Chlopicki S, Baranska M. Raman Imaging Providing Insights into Chemical Composition of Lipid Droplets of Different Size and Origin: In Hepatocytes and Endothelium. Anal Chem 2014; 86:6666-74. [DOI: 10.1021/ac501395g] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Katarzyna Majzner
- Jagiellonian
Centre for Experimental Therapeutics (JCET), Jagiellonian University, Bobrzynskiego 14, Krakow, 30-348, Poland
- Faculty
of Chemistry, Jagiellonian University, Ingardena 3, Krakow, 30-060, Poland
| | - Kamila Kochan
- Jagiellonian
Centre for Experimental Therapeutics (JCET), Jagiellonian University, Bobrzynskiego 14, Krakow, 30-348, Poland
- Faculty
of Chemistry, Jagiellonian University, Ingardena 3, Krakow, 30-060, Poland
| | - Neli Kachamakova-Trojanowska
- Jagiellonian
Centre for Experimental Therapeutics (JCET), Jagiellonian University, Bobrzynskiego 14, Krakow, 30-348, Poland
| | - Edyta Maslak
- Jagiellonian
Centre for Experimental Therapeutics (JCET), Jagiellonian University, Bobrzynskiego 14, Krakow, 30-348, Poland
| | - Stefan Chlopicki
- Jagiellonian
Centre for Experimental Therapeutics (JCET), Jagiellonian University, Bobrzynskiego 14, Krakow, 30-348, Poland
- Department
of Experimental Pharmacology, Chair of Pharmacology, Jagiellonian University, Grzegorzecka 16, Krakow, 31-531, Poland
| | - Malgorzata Baranska
- Jagiellonian
Centre for Experimental Therapeutics (JCET), Jagiellonian University, Bobrzynskiego 14, Krakow, 30-348, Poland
- Faculty
of Chemistry, Jagiellonian University, Ingardena 3, Krakow, 30-060, Poland
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19
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Dias FF, Zarantonello VC, Parreira GG, Chiarini-Garcia H, Melo RCN. The intriguing ultrastructure of lipid body organelles within activated macrophages. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:869-878. [PMID: 24786359 DOI: 10.1017/s143192761400066x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Macrophages are widely distributed immune system cells with essential functions in tissue homeostasis, apoptotic cell clearance, and first defense in infections. A distinguishing feature of activated macrophages participating in different situations such as inflammatory and metabolic diseases is the presence of increased numbers of lipid-rich organelles, termed lipid bodies (LBs) or lipid droplets, in their cytoplasm. LBs are considered structural markers of activated macrophages and are involved in different functions such as lipid metabolism, intracellular trafficking, and synthesis of inflammatory mediators. In this review, we revisit the distinct morphology of LB organelles actively formed within macrophages in response to infections and cell clearance, taking into account new insights provided by ultrastructural studies. We also discuss the LB interactions within macrophages, revealed by transmission electron microscopy, with a focus on the remarkable LB-phagosome association and discuss potential links between structural aspects and function.
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Affiliation(s)
- Felipe F Dias
- 1Laboratory of Cellular Biology,Department of Biology,Federal University of Juiz de Fora (UFJF),Juiz de Fora,MG 36036-900,Brazil
| | - Victor C Zarantonello
- 1Laboratory of Cellular Biology,Department of Biology,Federal University of Juiz de Fora (UFJF),Juiz de Fora,MG 36036-900,Brazil
| | - Gleydes G Parreira
- 2Laboratory of Structural Biology and Reproduction,Federal University of Minas Gerais (UFMG),Belo Horizonte,MG 31270-901,Brazil
| | - Hélio Chiarini-Garcia
- 2Laboratory of Structural Biology and Reproduction,Federal University of Minas Gerais (UFMG),Belo Horizonte,MG 31270-901,Brazil
| | - Rossana C N Melo
- 1Laboratory of Cellular Biology,Department of Biology,Federal University of Juiz de Fora (UFJF),Juiz de Fora,MG 36036-900,Brazil
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