1
|
Root-Bernstein R. T-Cell Receptor Sequences Identify Combined Coxsackievirus- Streptococci Infections as Triggers for Autoimmune Myocarditis and Coxsackievirus- Clostridia Infections for Type 1 Diabetes. Int J Mol Sci 2024; 25:1797. [PMID: 38339075 PMCID: PMC10855694 DOI: 10.3390/ijms25031797] [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: 11/09/2023] [Revised: 01/19/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
Recent research suggests that T-cell receptor (TCR) sequences expanded during human immunodeficiency virus and SARS-CoV-2 infections unexpectedly mimic these viruses. The hypothesis tested here is that TCR sequences expanded in patients with type 1 diabetes mellitus (T1DM) and autoimmune myocarditis (AM) mimic the infectious triggers of these diseases. Indeed, TCR sequences mimicking coxsackieviruses, which are implicated as triggers of both diseases, are statistically significantly increased in both T1DM and AM patients. However, TCRs mimicking Clostridia antigens are significantly expanded in T1DM, whereas TCRs mimicking Streptococcal antigens are expanded in AM. Notably, Clostridia antigens mimic T1DM autoantigens, such as insulin and glutamic acid decarboxylase, whereas Streptococcal antigens mimic cardiac autoantigens, such as myosin and laminins. Thus, T1DM may be triggered by combined infections of coxsackieviruses with Clostridia bacteria, while AM may be triggered by coxsackieviruses with Streptococci. These TCR results are consistent with both epidemiological and clinical data and recent experimental studies of cross-reactivities of coxsackievirus, Clostridial, and Streptococcal antibodies with T1DM and AM antigens. These data provide the basis for developing novel animal models of AM and T1DM and may provide a generalizable method for revealing the etiologies of other autoimmune diseases. Theories to explain these results are explored.
Collapse
|
2
|
Ebrahim S, Weigert R. Intravital microscopy in mammalian multicellular organisms. Curr Opin Cell Biol 2019; 59:97-103. [PMID: 31125832 PMCID: PMC6726551 DOI: 10.1016/j.ceb.2019.03.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/25/2019] [Accepted: 03/29/2019] [Indexed: 12/22/2022]
Abstract
Imaging subcellular processes in live animals is no longer a dream. The development of Intravital Subcellular Microscopy (ISMic) combined with the astounding repertoire of available mouse models makes it possible to investigate processes such as membrane trafficking in mammalian living tissues under native conditions. This has provided the unique opportunity to answer questions that cannot be otherwise addressed in reductionist model systems and to link cell biology to tissue pathophysiology.
Collapse
Affiliation(s)
- Seham Ebrahim
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Dr. Rm 2050B, Bethesda, MD, 20892, USA
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Dr. Rm 2050B, Bethesda, MD, 20892, USA.
| |
Collapse
|
3
|
Porat-Shliom N, Harding OJ, Malec L, Narayan K, Weigert R. Mitochondrial Populations Exhibit Differential Dynamic Responses to Increased Energy Demand during Exocytosis In Vivo. iScience 2019; 11:440-449. [PMID: 30661001 PMCID: PMC6355620 DOI: 10.1016/j.isci.2018.12.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 10/14/2018] [Accepted: 12/28/2018] [Indexed: 12/15/2022] Open
Abstract
Mitochondria are dynamic organelles undergoing fission, fusion, and translocation. These processes have been studied in cultured cells; however, little is known about their regulation in cells within tissues in vivo. We applied four-dimensional intravital microscopy to address this in secretory cells of the salivary gland. We found that mitochondria are organized in two populations: one juxtaposed to the basolateral plasma membrane and the other dispersed in the cytosol. Under basal conditions, central mitochondria exhibit microtubule-dependent motility and low fusion rate, whereas basolateral mitochondria are static and display high fusion rate. Increasing cellular energy demand by β-adrenergic stimulation of regulated exocytosis selectively enhanced motility and fusion of central mitochondria. Inhibition of microtubule polymerization led to inhibition of central mitochondrial motility and fusion and a marked reduction in exocytosis. This study reveals a conserved heterogeneity in mitochondrial positioning and dynamics in exocrine tissues that may have fundamental implications in organ pathophysiology. In the salivary glands, mitochondria exist in two populations: basolateral and central Basolateral mitochondria are static and frequently fuse Central mitochondria are highly motile and rarely fuse Exocytosis elicits selective, microtubule-dependent response in central mitochondria
Collapse
Affiliation(s)
- Natalie Porat-Shliom
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA; Cell Biology and Imaging Section, Thoracic and Gastrointestinal Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Olivia J Harding
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lenka Malec
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kedar Narayan
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 8560 Progress Drive, Frederick, MD 21701, USA; Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.
| |
Collapse
|
4
|
Ebrahim S, Liu J, Weigert R. The Actomyosin Cytoskeleton Drives Micron-Scale Membrane Remodeling In Vivo Via the Generation of Mechanical Forces to Balance Membrane Tension Gradients. Bioessays 2018; 40:e1800032. [PMID: 30080263 DOI: 10.1002/bies.201800032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/29/2018] [Indexed: 12/31/2022]
Abstract
The remodeling of biological membranes is crucial for a vast number of cellular activities and is an inherently multiscale process in both time and space. Seminal work has provided important insights into nanometer-scale membrane deformations, and highlighted the remarkable variation and complexity in the underlying molecular machineries and mechanisms. However, how membranes are remodeled at the micron-scale, particularly in vivo, remains poorly understood. Here, we discuss how using regulated exocytosis of large (1.5-2.0 μm) membrane-bound secretory granules in the salivary gland of live mice as a model system, has provided evidence for the importance of the actomyosin cytoskeleton in micron-scale membrane remodeling in physiological conditions. We highlight some of these advances, and present mechanistic hypotheses for how the various biochemical and biophysical properties of distinct actomyosin networks may drive this process.
Collapse
Affiliation(s)
- Seham Ebrahim
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.,National Institutes of Health, Bethesda, MD 20892, USA
| | - Jian Liu
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| |
Collapse
|
5
|
Milberg O, Shitara A, Ebrahim S, Masedunskas A, Tora M, Tran DT, Chen Y, Conti MA, Adelstein RS, Ten Hagen KG, Weigert R. Concerted actions of distinct nonmuscle myosin II isoforms drive intracellular membrane remodeling in live animals. J Cell Biol 2017; 216:1925-1936. [PMID: 28600434 PMCID: PMC5496622 DOI: 10.1083/jcb.201612126] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/02/2017] [Accepted: 05/02/2017] [Indexed: 12/11/2022] Open
Abstract
Membrane remodeling plays a fundamental role during a variety of biological events. However, the dynamics and the molecular mechanisms regulating this process within cells in mammalian tissues in situ remain largely unknown. In this study, we use intravital subcellular microscopy in live mice to study the role of the actomyosin cytoskeleton in driving the remodeling of membranes of large secretory granules, which are integrated into the plasma membrane during regulated exocytosis. We show that two isoforms of nonmuscle myosin II, NMIIA and NMIIB, control distinct steps of the integration process. Furthermore, we find that F-actin is not essential for the recruitment of NMII to the secretory granules but plays a key role in the assembly and activation of NMII into contractile filaments. Our data support a dual role for the actomyosin cytoskeleton in providing the mechanical forces required to remodel the lipid bilayer and serving as a scaffold to recruit key regulatory molecules.
Collapse
Affiliation(s)
- Oleg Milberg
- Intracellular Membrane Trafficking Section, National Institutes of Health, Bethesda, MD
| | - Akiko Shitara
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD.,Intracellular Membrane Trafficking Section, National Institutes of Health, Bethesda, MD
| | - Seham Ebrahim
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Andrius Masedunskas
- Intracellular Membrane Trafficking Section, National Institutes of Health, Bethesda, MD.,School of Medical Sciences, University of New South Wales, Sidney, Australia
| | - Muhibullah Tora
- Intracellular Membrane Trafficking Section, National Institutes of Health, Bethesda, MD
| | - Duy T Tran
- Developmental Glycobiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD
| | - Yun Chen
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Mary Anne Conti
- Laboratory of Molecular Cardiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Robert S Adelstein
- Laboratory of Molecular Cardiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Kelly G Ten Hagen
- Developmental Glycobiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD .,Intracellular Membrane Trafficking Section, National Institutes of Health, Bethesda, MD
| |
Collapse
|
6
|
Orchestrated content release from Drosophila glue-protein vesicles by a contractile actomyosin network. Nat Cell Biol 2015; 18:181-90. [DOI: 10.1038/ncb3288] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 11/11/2015] [Indexed: 12/22/2022]
|
7
|
Shitara A, Weigert R. Imaging membrane remodeling during regulated exocytosis in live mice. Exp Cell Res 2015; 337:219-25. [PMID: 26160452 DOI: 10.1016/j.yexcr.2015.06.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/28/2015] [Indexed: 10/23/2022]
Abstract
In this mini-review we focus on the use of time-lapse light microscopy to study membrane remodeling during protein secretion in live animals. In particular, we highlight how subcellular intravital microscopy has enabled imaging the dynamics of both individual secretory vesicles and the plasma membrane, during different steps in the exocytic process. This powerful approach has provided us with the unique opportunity to unravel the role of the actin cytoskeleton in regulating this process under physiological conditions, and to overcome the shortcomings of more reductionist model systems.
Collapse
Affiliation(s)
- Akiko Shitara
- Intracellular Membrane Trafficking Section, Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, 30 Convent Dr. 303A, Bethesda, MD 20892-4340, United States
| | - Roberto Weigert
- Intracellular Membrane Trafficking Section, Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, 30 Convent Dr. 303A, Bethesda, MD 20892-4340, United States.
| |
Collapse
|
8
|
Unresolved issues in theories of autoimmune disease using myocarditis as a framework. J Theor Biol 2014; 375:101-123. [PMID: 25484004 DOI: 10.1016/j.jtbi.2014.11.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 11/10/2014] [Accepted: 11/20/2014] [Indexed: 11/20/2022]
Abstract
Many theories of autoimmune disease have been proposed since the discovery that the immune system can attack the body. These theories include the hidden or cryptic antigen theory, modified antigen theory, T cell bypass, T cell-B cell mismatch, epitope spread or drift, the bystander effect, molecular mimicry, anti-idiotype theory, antigenic complementarity, and dual-affinity T cell receptors. We critically review these theories and relevant mathematical models as they apply to autoimmune myocarditis. All theories share the common assumption that autoimmune diseases are triggered by environmental factors such as infections or chemical exposure. Most, but not all, theories and mathematical models are unifactorial assuming single-agent causation of disease. Experimental and clinical evidence and mathematical models exist to support some aspects of most theories, but evidence/models that support one theory almost invariably supports other theories as well. More importantly, every theory (and every model) lacks the ability to account for some key autoimmune disease phenomena such as the fundamental roles of innate immunity, sex differences in disease susceptibility, the necessity for adjuvants in experimental animal models, and the often paradoxical effect of exposure timing and dose on disease induction. We argue that a more comprehensive and integrated theory of autoimmunity associated with new mathematical models is needed and suggest specific experimental and clinical tests for each major theory that might help to clarify how they relate to clinical disease and reveal how theories are related.
Collapse
|
9
|
Masedunskas A, Sramkova M, Weigert R. Homeostasis of the apical plasma membrane during regulated exocytosis in the salivary glands of live rodents. BIOARCHITECTURE 2014; 1:225-229. [PMID: 22754613 PMCID: PMC3384574 DOI: 10.4161/bioa.18405] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In exocrine organs such as the salivary glands, fluids and proteins are secreted into ductal structures by distinct mechanisms that are tightly coupled. In the acinar cells, the major secretory units of the salivary glands, fluids are secreted into the acinar canaliculi through paracellular and intracellular transport, whereas proteins are stored in large granules that undergo exocytosis and fuse with the apical plasma membranes releasing their content into the canaliculi. Both secretory processes elicit a remodeling of the apical plasma membrane that has not been fully addressed in in vitro or ex vivo models. Recently, we have studied regulated exocytosis in the salivary glands of live rodents, focusing on the role that actin and myosin plays in this process. We observed that during exocytosis both secretory granules and canaliculi are subjected to the hydrostatic pressure generated by fluid secretion. Furthermore, the absorption of the membranes of the secretory granules contributes to the expansion and deformation of the canaliculi. Here we suggest that the homeostasis of the apical plasma membranes during exocytosis is maintained by various strategies that include: (1) membrane retrieval via compensatory endocytosis, (2) increase of the surface area via membrane folds and (3) recruitment of a functional actomyosin complex. Our observations underscore the important relationship between tissue architecture and cellular response, and highlight the potential of investigating biological processes in vivo by using intravital microscopy.
Collapse
|
10
|
Masedunskas A, Appaduray M, Hardeman EC, Gunning PW. What makes a model system great? INTRAVITAL 2014. [DOI: 10.4161/intv.26287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
11
|
Weigert R, Porat-Shliom N, Amornphimoltham P. Imaging cell biology in live animals: ready for prime time. ACTA ACUST UNITED AC 2013; 201:969-79. [PMID: 23798727 PMCID: PMC3691462 DOI: 10.1083/jcb.201212130] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Time-lapse fluorescence microscopy is one of the main tools used to image subcellular structures in living cells. Yet for decades it has been applied primarily to in vitro model systems. Thanks to the most recent advancements in intravital microscopy, this approach has finally been extended to live rodents. This represents a major breakthrough that will provide unprecedented new opportunities to study mammalian cell biology in vivo and has already provided new insight in the fields of neurobiology, immunology, and cancer biology.
Collapse
Affiliation(s)
- Roberto Weigert
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | | |
Collapse
|
12
|
Multiple roles for the actin cytoskeleton during regulated exocytosis. Cell Mol Life Sci 2012; 70:2099-121. [PMID: 22986507 DOI: 10.1007/s00018-012-1156-5] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 08/28/2012] [Accepted: 08/30/2012] [Indexed: 01/01/2023]
Abstract
Regulated exocytosis is the main mechanism utilized by specialized secretory cells to deliver molecules to the cell surface by virtue of membranous containers (i.e., secretory vesicles). The process involves a series of highly coordinated and sequential steps, which include the biogenesis of the vesicles, their delivery to the cell periphery, their fusion with the plasma membrane, and the release of their content into the extracellular space. Each of these steps is regulated by the actin cytoskeleton. In this review, we summarize the current knowledge regarding the involvement of actin and its associated molecules during each of the exocytic steps in vertebrates, and suggest that the overall role of the actin cytoskeleton during regulated exocytosis is linked to the architecture and the physiology of the secretory cells under examination. Specifically, in neurons, neuroendocrine, endocrine, and hematopoietic cells, which contain small secretory vesicles that undergo rapid exocytosis (on the order of milliseconds), the actin cytoskeleton plays a role in pre-fusion events, where it acts primarily as a functional barrier and facilitates docking. In exocrine and other secretory cells, which contain large secretory vesicles that undergo slow exocytosis (seconds to minutes), the actin cytoskeleton plays a role in post-fusion events, where it regulates the dynamics of the fusion pore, facilitates the integration of the vesicles into the plasma membrane, provides structural support, and promotes the expulsion of large cargo molecules.
Collapse
|
13
|
Masedunskas A, Milberg O, Porat-Shliom N, Sramkova M, Wigand T, Amornphimoltham P, Weigert R. Intravital microscopy: a practical guide on imaging intracellular structures in live animals. BIOARCHITECTURE 2012; 2:143-57. [PMID: 22992750 PMCID: PMC3696059 DOI: 10.4161/bioa.21758] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2012] [Revised: 08/05/2012] [Accepted: 08/07/2012] [Indexed: 01/05/2023]
Abstract
Intravital microscopy is an extremely powerful tool that enables imaging several biological processes in live animals. Recently, the ability to image subcellular structures in several organs combined with the development of sophisticated genetic tools has made possible extending this approach to investigate several aspects of cell biology. Here we provide a general overview of intravital microscopy with the goal of highlighting its potential and challenges. Specifically, this review is geared toward researchers that are new to intravital microscopy and focuses on practical aspects of carrying out imaging in live animals. Here we share the know-how that comes from first-hand experience, including topics such as choosing the right imaging platform and modality, surgery and stabilization techniques, anesthesia and temperature control. Moreover, we highlight some of the approaches that facilitate subcellular imaging in live animals by providing numerous examples of imaging selected organelles and the actin cytoskeleton in multiple organs.
Collapse
Affiliation(s)
- Andrius Masedunskas
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
- Department of Biology; University of North Carolina at Chapel Hill; Chapel Hill, NC USA
| | - Oleg Milberg
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
- Department of Chemical and Biochemical Engineering; Rutgers University; Piscataway, NJ USA
- Department of Biomedical Engineering; Rutgers University; Piscataway, NJ USA
| | - Natalie Porat-Shliom
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
| | - Monika Sramkova
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
| | - Tim Wigand
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
| | - Panomwat Amornphimoltham
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
| | - Roberto Weigert
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
| |
Collapse
|