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Grubišić V, Gulbransen BD. Astrocyte Cell Surface Antigen 2 and Other Potential Cell Surface Markers of Enteric glia in the Mouse Colon. ASN Neuro 2022; 14:17590914221083203. [PMID: 35593118 PMCID: PMC9125112 DOI: 10.1177/17590914221083203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Enteric glia regulate gut functions in health and disease through diverse interactions with neurons and immune cells. Intracellular localization of traditional markers of enteric glia such as GFAP, s100b, and Sox10 makes them incompatible for studies that require antigen localization at the cell surface. Thus, new tools are needed for probing the heterogeneous roles of enteric glia at the protein, cell, and functional levels. Here we selected several cell surface antigens including Astrocyte Cell Surface Marker 2 (ACSA2), Cluster of differentiation 9 (CD9), lysophosphatidic acid receptor 1 (LPAR1), and Proteolipid protein 1 (PLP1) as potential markers of enteric glia. We tested their specificity for enteric glia using published single-cell/-nuclei and glia-specific translating mRNA enriched transcriptome datasets, immunolabeling, and flow cytometry. The data show that ACSA2 is a specific marker of mucosal and myenteric glia while other markers are suitable for identifying all subpopulations of enteric glia (LPAR1), glia and immune cells (CD9), or are not suitable for cell-surface labeling (PLP1). These new tools will be useful for future work focused on understanding specific glial functions in health and disease.Summary StatementThis study identifies astrocyte cell surface antigen 2 as a novel marker of myenteric glia in the intestine. This, in combination with other markers identified in this study, could be used for selective targeting of enteric glia.
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Affiliation(s)
- Vladimir Grubišić
- Department of Physiology and Neuroscience program, Michigan State University, East Lansing, MI, USA
| | - Brian D. Gulbransen
- Department of Physiology and Neuroscience program, Michigan State University, East Lansing, MI, USA,Brian D. Gulbransen, Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA.
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Grubišić V, Bali V, Fried DE, Eltzschig HK, Robson SC, Mazei-Robison MS, Gulbransen BD. Enteric glial adenosine 2B receptor signaling mediates persistent epithelial barrier dysfunction following acute DSS colitis. Mucosal Immunol 2022; 15:964-976. [PMID: 35869148 PMCID: PMC9385475 DOI: 10.1038/s41385-022-00550-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 06/15/2022] [Accepted: 07/01/2022] [Indexed: 02/04/2023]
Abstract
Intestinal epithelial barrier function is compromised in inflammatory bowel disease and barrier dysfunction contributes to disease progression. Extracellular nucleotides/nucleosides generated in gut inflammation may regulate barrier function through actions on diverse cell types. Enteric glia modulate extracellular purinergic signaling and exert pathophysiological effects on mucosal permeability. These glia may regulate inflammation with paracrine responses, theoretically mediated via adenosine 2B receptor (A2BR) signaling. As the cell-specific roles of A2BRs in models of colitis and barrier dysfunction are unclear, we studied glial A2BRs in acute dextran sodium sulfate (DSS) colitis. We performed and validated conditional ablation of glial A2BRs in Sox10CreERT2+/-;Adora2bf/f mice. Overt intestinal disease activity indices in DSS-colitis were comparable between Sox10CreERT2+/-;Adora2bf/f mice and littermate controls. However, ablating glial A2BRs protected against barrier dysfunction following acute DSS-colitis. These benefits were associated with the normalization of tight junction protein expression and localization including claudin-1, claudin-8, and occludin. Glial A2BR signaling increased levels of proinflammatory mediators in the colon and cell-intrinsic regulation of genes including Csf3, Cxcl1, Cxcl10, and Il6. Our studies show that glial A2BR signaling exacerbates immune responses during DSS-colitis and that this adenosinergic cell-specific mechanism contributes to persistent gut epithelial barrier dysfunction.
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Affiliation(s)
- Vladimir Grubišić
- Department of Physiology and Neuroscience program, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biomedical Sciences and Center for Biomedical Innovation, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, 11568, USA
| | - Vedrana Bali
- Department of Physiology and Neuroscience program, Michigan State University, East Lansing, MI, 48824, USA
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, 48824, USA
| | - David E Fried
- Department of Physiology and Neuroscience program, Michigan State University, East Lansing, MI, 48824, USA
| | - Holger K Eltzschig
- McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Simon C Robson
- Division of Gastroenterology, Departments of Medicine and Anesthesia, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Michelle S Mazei-Robison
- Department of Physiology and Neuroscience program, Michigan State University, East Lansing, MI, 48824, USA
| | - Brian D Gulbransen
- Department of Physiology and Neuroscience program, Michigan State University, East Lansing, MI, 48824, USA.
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Chow AK, Grubišić V, Gulbransen BD. Enteric Glia Regulate Lymphocyte Activation via Autophagy-Mediated MHC-II Expression. Cell Mol Gastroenterol Hepatol 2021; 12:1215-1237. [PMID: 34166814 PMCID: PMC8449089 DOI: 10.1016/j.jcmgh.2021.06.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 06/09/2021] [Accepted: 06/10/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Enteric glial cells express type II major histocompatibility complex (MHC-II) molecules in Crohn's disease and Chagas disease, but it is unclear whether the expressed molecules are functional. We examined the capabilities of enteric glia to act as an antigen-presenting cell in vivo and whether glial MHC-II has immunomodulatory effects. METHODS We generated Sox10CreERT2;IABfl/fl mice to ablate MHC-II in enteric glia after exposure to tamoxifen. We measured phagocytic activity and autophagy activation to assess potential peptide sources loaded onto glial MHC-II and measured T- and B-lymphocyte activation and serum and colonic tissue cytokine levels to study enteric glial immunomodulatory capabilities. RESULTS Enteric glia express MHC-II molecules in response to a subclinical dose of interferon-γ and lipopolysaccharide in vivo. Glial MHC-II expression contributes to effective B-lymphocyte and T-lymphocyte activation with marked effects on T-helper cell (Th)17 and regulatory T cell subtypes. No effect on Th1 or Th2 subtypes was observed. Enteric glial MHC-II does not have a major effect on serum or colonic tissue cytokine levels but may influence local cytokine levels. Glial MHC-II expression requires the activation of autophagy pathways, but activating autophagy alone is not sufficient to drive glial MHC-II expression. CONCLUSIONS Enteric glia express MHC-II as a mechanism to tune intestinal immune responses. Glial autophagy is triggered in response to proinflammatory stimuli and induces glial antigen presentation, which functions to modulate the activation of T-lymphocyte subsets involved in tolerance. These observations suggest that enteric glia may express MHC-II to maintain immune homeostasis during inflammatory conditions such as Crohn's disease.
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Affiliation(s)
| | | | - Brian D. Gulbransen
- Department of Physiology, East Lansing, Michigan,Neuroscience Program, Michigan State University, East Lansing, Michigan,Correspondence Address correspondence to: Brian Gulbransen, PhD, Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, Michigan 48824. fax: (517) 355-5125.
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Hernandez S, Morales-Soto W, Grubišić V, Fried D, Gulbransen BD. Pyridostigmine bromide exposure creates chronic, underlying neuroimmune disruption in the gastrointestinal tract and brain that alters responses to palmitoylethanolamide in a mouse model of Gulf War Illness. Neuropharmacology 2020; 179:108264. [PMID: 32758565 DOI: 10.1016/j.neuropharm.2020.108264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/08/2020] [Accepted: 07/27/2020] [Indexed: 12/13/2022]
Abstract
Gulf War Illness (GWI) is a chronic multisymptom illness that includes gastrointestinal disorders. Although the exact etiology of GWI is unknown, exposure to the drug pyridostigmine bromide (PB) is considered a major factor. Exposure to PB drives enteric neuroinflammation, promotes immunosuppression, and alters physiological functions of the colon in the short term but whether exposure to PB is sufficient to promote long term dysfunction is not known. Here, we tested whether exposure to PB is sufficient to drive long term changes that reflect GWI, and whether the endogenous anti-inflammatory mediator palmitoylethanolamide (PEA) is sufficient to reduce the detrimental effects of PB in the gut and brain of mice. Exposure to PB alone was not sufficient to cause major changes in neuromuscular transmission but did drive major changes by altering the effects of PEA. Calcium imaging data show that the mechanisms responsible include a shift in receptor signaling mediated by TRPV1, endocannabinoids, and peroxisome proliferator-activated receptors alpha (PPARα). Additional mechanisms include the development of glial reactivity and changes in enteric neurochemical coding and survival. PB and PEA caused major shifts in pro-inflammatory cytokines/chemokines in the brain and colon that persisted up to 5 months following exposure. Many of the effects of PB and PEA exhibit significant sex differences. Together, these results highlight novel mechanisms whereby PB promotes long-lasting changes in nervous system and immune function by inducing occult neuroplasticity that is revealed by subsequent exposure to unrelated drugs in a sex dependent manner.
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Affiliation(s)
- Siomara Hernandez
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA
| | - Wilmarie Morales-Soto
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA
| | - Vladimir Grubišić
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA
| | - David Fried
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA
| | - Brian D Gulbransen
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA.
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Grubišić V, McClain JL, Fried DE, Grants I, Rajasekhar P, Csizmadia E, Ajijola OA, Watson RE, Poole DP, Robson SC, Christofi FL, Gulbransen BD. Enteric Glia Modulate Macrophage Phenotype and Visceral Sensitivity following Inflammation. Cell Rep 2020; 32:108100. [PMID: 32905782 PMCID: PMC7518300 DOI: 10.1016/j.celrep.2020.108100] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 07/02/2020] [Accepted: 08/11/2020] [Indexed: 12/20/2022] Open
Abstract
Mechanisms resulting in abdominal pain include altered neuro-immune interactions in the gastrointestinal tract, but the signaling processes that link immune activation with visceral hypersensitivity are unresolved. We hypothesized that enteric glia link the neural and immune systems of the gut and that communication between enteric glia and immune cells modulates the development of visceral hypersensitivity. To this end, we manipulated a major mechanism of glial intercellular communication that requires connexin-43 and assessed the effects on acute and chronic inflammation, visceral hypersensitivity, and immune responses. Deleting connexin-43 in glia protected against the development of visceral hypersensitivity following chronic colitis. Mechanistically, the protective effects of glial manipulation were mediated by disrupting the glial-mediated activation of macrophages through the macrophage colony-stimulating factor. Collectively, our data identified enteric glia as a critical link between gastrointestinal neural and immune systems that could be harnessed by therapies to ameliorate abdominal pain.
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Affiliation(s)
- Vladimir Grubišić
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI 48824, USA
| | - Jonathon L McClain
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI 48824, USA
| | - David E Fried
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI 48824, USA
| | - Iveta Grants
- Department of Anesthesiology, The Wexner Medical Center, The Ohio State University, 420 West 12th Avenue, Room 216, Columbus, OH 43210, USA
| | - Pradeep Rajasekhar
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science & Technology, Melbourne, VIC, Australia
| | - Eva Csizmadia
- Division of Gastroenterology, Department of Medicine and of Anesthesia, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Olujimi A Ajijola
- Cardiac Arrhythmia Center, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, USA
| | - Ralph E Watson
- Department of Medicine, Michigan State University, East Lansing, MI 48824, USA
| | - Daniel P Poole
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science & Technology, Melbourne, VIC, Australia
| | - Simon C Robson
- Division of Gastroenterology, Department of Medicine and of Anesthesia, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Fievos L Christofi
- Department of Anesthesiology, The Wexner Medical Center, The Ohio State University, 420 West 12th Avenue, Room 216, Columbus, OH 43210, USA
| | - Brian D Gulbransen
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI 48824, USA.
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Hernandez-Rivera S, Grubišić V, Fried D, Isufi K, Gulbransen BD. Long‐term gastrointestinal motility disruption in a mouse Gulf War Illness model treated with palmitoylethanolamide. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.03966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Grubišić V, Perez-Medina AL, Fried DE, Sévigny J, Robson SC, Galligan JJ, Gulbransen BD. NTPDase1 and -2 are expressed by distinct cellular compartments in the mouse colon and differentially impact colonic physiology and function after DSS colitis. Am J Physiol Gastrointest Liver Physiol 2019; 317:G314-G332. [PMID: 31188623 PMCID: PMC6774087 DOI: 10.1152/ajpgi.00104.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
ATP is both an important mediator of physiological gut functions such as motility and epithelial function, and a key danger signal that mediates cell death and tissue damage. The actions of extracellular ATP are regulated through the catalytic functions extracellular nucleoside triphosphate diphosphohydrolase-1 (NTPDase1), -2, -3, and -8, which ultimately generate nucleosides. Ectonucleotidases have distinct cellular associations, but the specific locations and functional roles of individual NTPDases in the intestine are still poorly understood. Here, we tested the hypothesis that differential and cell-selective regulation of purine hydrolysis by NTPDase1 and -2 plays important roles in gut physiology and disease. We studied Entpd1 and Entpd2 null mice in health and following colitis driven by 2% dextran sulfate sodium (DSS) administration using functional readouts of gut motility, epithelial barrier function, and neuromuscular communication. NTPDase1 is expressed by immune cells, and the ablation of Entpd1 altered glial numbers in the myenteric plexus. NTPDase2 is expressed by enteric glia, and the ablation of Entpd2 altered myenteric neuron numbers. Mice lacking either NTPDase1 or -2 exhibited decreased inhibitory neuromuscular transmission and altered components of inhibitory junction potentials. Ablation of Entpd2 increased gut permeability following inflammation. In conclusion, the location- and context-dependent extracellular nucleotide phosphohydrolysis by NTPDase1 and -2 substantially impacts gut function in health and disease.NEW & NOTEWORTHY Purines are important mediators of gastrointestinal physiology and pathophysiology. Nucleoside triphosphate diphosphohydrolases (NTPDases) regulate extracellular purines, but the roles of specific NTPDases in gut functions are poorly understood. Here, we used Entpd1- and Entpd2-deficient mice to show that the differential and cell-selective regulation of purine hydrolysis by NTPDase1 and -2 plays important roles in barrier function, gut motility, and neuromuscular communication in health and disease.
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Affiliation(s)
- Vladimir Grubišić
- 1Department of Physiology and Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - Alberto L. Perez-Medina
- 2Department of Pharmacology and Toxicology and Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - David E. Fried
- 1Department of Physiology and Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - Jean Sévigny
- 3Centre de recherche du CHU de Québec–Université Laval, Québec City, Quebec, Canada,4Département de Microbiologie-Infectiologie et d'Immunologie, Faculté de Médecine, Université Laval, Québec City, Quebec, Canada
| | - Simon C. Robson
- 5Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - James J. Galligan
- 2Department of Pharmacology and Toxicology and Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - Brian D. Gulbransen
- 1Department of Physiology and Neuroscience Program, Michigan State University, East Lansing, Michigan
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Hernandez‐Rivera S, Grubišić V, Fried D, Gulbransen BD. Gastrointestinal neuroimmune disruption in a mouse Gulf War Illness model. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.763.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - David Fried
- PhysiologyMichigan State UniversityEast LansingMI
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Abstract
Gulf War illness (GWI) is a chronic multisymptom disorder that is prominent in Gulf War veterans. Major unexplained symptoms of GWI include functional gastrointestinal disorders and undiagnosed illnesses, including neurologic disorders. Exposure to the antinerve gas drug pyridostigmine bromide (PB) is linked to the development of GWI, but the exact mechanisms remain unclear. Here, we tested the hypothesis that PB alters gut function by disrupting the neural and immune systems of the intestine. We exposed male and female mice to physiologically comparable amounts of PB that match the dose, route, and time frame of exposure experienced by Gulf War veterans and assessed the acute and chronic impacts on gastrointestinal functions, the functional architecture of the enteric nervous system, and immune responses in the gut and brain. Exposure to PB drove acute alterations to colonic motility and structure in both male and female mice that transitioned to chronic changes in gut functions. PB drove acute alterations to enteric neural and glial activity, glial reactivity, and neuron survival with glial reactivity persisting into the chronic phase in male mice. Despite having no effect on colonic permeability, exposure to PB caused major shifts in the expression of proinflammatory cytokines and chemokines in the colon and brain that suggest immunosuppressive effects. Interestingly, immune disruption was still evident in the colon and brain in female animals at 1 mo following exposure to PB. Together, our results show that the paradigm of PB exposure experienced by veterans of the Persian Gulf War contributes to long-lasting pathophysiology by driving enteric neuroinflammation, promoting immunosuppression, and altering functional anatomy of the colon in a sex-dependent manner.-Hernandez, S., Fried, D. E., Grubišić, V., McClain, J. L., Gulbransen, B. D. Gastrointestinal neuroimmune disruption in a mouse model of Gulf War illness.
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Affiliation(s)
- Siomara Hernandez
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA
| | - David E Fried
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA
| | - Vladimir Grubišić
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA
| | - Jonathon L McClain
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA
| | - Brian D Gulbransen
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA.,Neuroscience Program, Michigan State University, East Lansing, Michigan, USA
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Grubišić V, Verkhratsky A, Zorec R, Parpura V. Enteric glia regulate gut motility in health and disease. Brain Res Bull 2018; 136:109-117. [PMID: 28363846 PMCID: PMC5620110 DOI: 10.1016/j.brainresbull.2017.03.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/20/2017] [Accepted: 03/28/2017] [Indexed: 12/16/2022]
Abstract
The enteric nervous system, often referred to as the second brain, is the largest assembly of neurons and glia outside the central nervous system. The enteric nervous system resides within the wall of the digestive tract and regulates local gut reflexes involved in gastrointestinal motility and fluid transport; these functions can be accomplished in the absence of the extrinsic innervation from the central nervous system. It is neurons and their circuitry within the enteric nervous system that govern the gut reflexes. However, it is becoming clear that enteric glial cells are also actively involved in this process through the bidirectional signaling with neurons and other cells in the gut wall. We synthesize the recently discovered modulatory roles of enteric gliotransmission in gut motility and provide our perspective for future lines of research.
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Affiliation(s)
- Vladimir Grubišić
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA; Neuroscience Program, Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA
| | - Alexei Verkhratsky
- The University of Manchester, Manchester, UK; Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology University of Ljubljana, Ljubljana, Slovenia; Celica BIOMEDICAL, Ljubljana, Slovenia
| | - Vladimir Parpura
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.
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Buscemi L, Ginet V, Lopatar J, Montana V, Pucci L, Spagnuolo P, Zehnder T, Grubišić V, Truttman A, Sala C, Hirt L, Parpura V, Puyal J, Bezzi P. Homer1 Scaffold Proteins Govern Ca2+ Dynamics in Normal and Reactive Astrocytes. Cereb Cortex 2017; 27:2365-2384. [PMID: 27075036 PMCID: PMC5963825 DOI: 10.1093/cercor/bhw078] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In astrocytes, the intracellular calcium (Ca2+) signaling mediated by activation of metabotropic glutamate receptor 5 (mGlu5) is crucially involved in the modulation of many aspects of brain physiology, including gliotransmission. Here, we find that the mGlu5-mediated Ca2+ signaling leading to release of glutamate is governed by mGlu5 interaction with Homer1 scaffolding proteins. We show that the long splice variants Homer1b/c are expressed in astrocytic processes, where they cluster with mGlu5 at sites displaying intense local Ca2+ activity. We show that the structural and functional significance of the Homer1b/c-mGlu5 interaction is to relocate endoplasmic reticulum (ER) to the proximity of the plasma membrane and to optimize Ca2+ signaling and glutamate release. We also show that in reactive astrocytes the short dominant-negative splice variant Homer1a is upregulated. Homer1a, by precluding the mGlu5-ER interaction decreases the intensity of Ca2+ signaling thus limiting the intensity and the duration of glutamate release by astrocytes. Hindering upregulation of Homer1a with a local injection of short interfering RNA in vivo restores mGlu5-mediated Ca2+ signaling and glutamate release and sensitizes astrocytes to apoptosis. We propose that Homer1a may represent one of the cellular mechanisms by which inflammatory astrocytic reactions are beneficial for limiting brain injury.
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Affiliation(s)
- Lara Buscemi
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
- Stroke Laboratory, Neurology Service, Department of Clinical Neurosciences, University Hospital Centre and University of Lausanne, CH-1011 Lausanne, Switzerland
| | - Vanessa Ginet
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
- Division of Neonatology, Department of Paediatrics and Paediatric Surgery, University Hospital Centre and University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Jan Lopatar
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
| | - Vedrana Montana
- Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy and Nanotechnology Laboratories, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Luca Pucci
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
| | - Paola Spagnuolo
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Tamara Zehnder
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
| | - Vladimir Grubišić
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy and Nanotechnology Laboratories, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Anita Truttman
- Division of Neonatology, Department of Paediatrics and Paediatric Surgery, University Hospital Centre and University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Carlo Sala
- CNR Institute of Neuroscience and Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Lorenz Hirt
- Stroke Laboratory, Neurology Service, Department of Clinical Neurosciences, University Hospital Centre and University of Lausanne, CH-1011 Lausanne, Switzerland
| | - Vladimir Parpura
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy and Nanotechnology Laboratories, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Julien Puyal
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
- Division of Neonatology, Department of Paediatrics and Paediatric Surgery, University Hospital Centre and University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Paola Bezzi
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
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Grubišić V, Gulbransen BD. Enteric glial activity regulates secretomotor function in the mouse colon but does not acutely affect gut permeability. J Physiol 2017; 595:3409-3424. [PMID: 28066889 DOI: 10.1113/jp273492] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 11/30/2016] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS The role of enteric glial cell activity in the acute regulation of epithelial barrier and secretomotor functions of the intestines under physiological conditions is not clear. We used transgenic mice to modify glial activity and found that enteric glia significantly contribute to the neurogenic ion transport while glial activity does not appear to play a major role in the acute regulation of barrier function. The selective activation of glial activity evoked electrogenic ion transport primarily through neural pathways and was sufficient to drive electrogenic ion transport to an extent equal to the direct activation of neurogenic ion transport. These findings provide novel insight into the cellular mechanisms that control fluid transport homeostasis in the intestine and might provide novel therapeutic avenues for functional diarrheal diseases. ABSTRACT Enteric glial cells are often implicated in the regulation of epithelial barrier and secretomotor functions of the intestines. But whether glial cell activity regulates these functions acutely under physiological conditions is not clear. We addressed this issue by using transgenic animal models to modify the activity of enteric glia, either reducing glial expression of connexin 43 in Sox10::CreERT2+/- /Cx43f/f mice or activating glial calcium responses in GFAP::hM3Dq mice, and tested the effects on colonic barrier function and electrogenic ion transport in Ussing chambers. We assessed neuronal-dependent and -independent contributions by activating or inhibiting neurogenic activity with veratridine and tetrodotoxin, respectively. Our results show that the reduction of glial Cx43 expression in Sox10::CreERT2+/- /Cx43f/f mice significantly reduced neurogenic ion transport. The selective glial activation in tissues from GFAP::hM3Dq mice evoked electrogenic ion transport to an extent equal to the direct activation of neurogenic ion transport with veratridine and glial driven responses consisted of both tetrodotoxin-sensitive and -insensitive components. The selective glial stimulation did not affect transmural ion conductance or cell-impermeant dye flux but the baseline ion conductance was more variable in Sox10::CreERT2+/- /Cx43f/f tissues. Together, our findings show that glial activity contributes to the regulation of electrogenic ion transport in the intestine through effects on neurons and possibly direct effects on epithelial cells. However, glial activity does not appear to play a major role in the acute regulation of barrier function. These findings provide novel insight into the cellular mechanisms that control fluid transport homeostasis in the intestine.
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Affiliation(s)
- Vladimir Grubišić
- Neuroscience Program, Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA
| | - Brian D Gulbransen
- Neuroscience Program, Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA
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Grubišić V, Parpura V. Two modes of enteric gliotransmission differentially affect gut physiology. Glia 2017; 65:699-711. [PMID: 28168732 DOI: 10.1002/glia.23121] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 01/07/2017] [Accepted: 01/10/2017] [Indexed: 11/08/2022]
Abstract
Enteric glia (EG) in the enteric nervous system can modulate neuronally regulated gut functions. Using molecular genetics, we assessed the effects that molecular entities expressed in EG and otherwise mediating two distinct mechanisms of gliotransmitter release, connexin 43 (Cx43) hemichannel vs. Ca2+ -dependent exocytosis, have on gut function. The expression of mutated Cx43G138R (which favors hemichannel, as opposed to gap-junctional activity) in EG increased gut motility in vivo, while a knock-down of Cx43 in EG resulted in the reduction of gut motility. However, inhibition of Ca2+ -dependent exocytosis in EG did not affect gut motility in vivo; rather, it increased the fecal pellet fluid content. Hampering either Cx43 expression or Ca2+ -dependent exocytosis in EG had an effect on colonic migrating motor complexes, mainly decreasing frequency and velocity of contractions ex vivo. Thus, EG can differentially modulate gut reflexes using the above two distinct mechanisms of gliotransmission.
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Affiliation(s)
- Vladimir Grubišić
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama.,Department of Physiology, Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - Vladimir Parpura
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama
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Abstract
Glia (from Greek γλοία meaning 'glue') pertains to non-neuronal cells in the central (CNS) and peripheral nervous system (PNS) that nourish neurons and maintain homeostasis. In addition, glia are now increasingly appreciated as active regulators of numerous physiological processes initially considered exclusively under neuronal regulation. For instance, enteric glia, a collection of glial cells residing within the walls of the intestinal tract, regulate intestinal motility, a well-characterized reflex controlled by enteric neurons. Enteric glia also interact with various non-neuronal cell types in the gut wall such as enterocytes, enteroendocrine and immune cells and are therefore emerging as important local regulators of diverse gut functions. The intricate molecular mechanisms that govern glia-mediated regulation are beginning to be discovered, but much remains unknown about the functions of enteric glia in health and disease. Here we present a current view of the enteric glia and their regulatory roles in gastrointestinal (GI) (patho)physiology; from GI motility and epithelial barrier function to enteric neuroinflammation.
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Affiliation(s)
- Vladimir Grubišić
- Neuroscience Program, Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA
| | - Brian D Gulbransen
- Neuroscience Program, Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA
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15
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Stenovec M, Lasič E, Božić M, Bobnar ST, Stout RF, Grubišić V, Parpura V, Zorec R. Ketamine Inhibits ATP-Evoked Exocytotic Release of Brain-Derived Neurotrophic Factor from Vesicles in Cultured Rat Astrocytes. Mol Neurobiol 2015; 53:6882-6896. [PMID: 26660497 DOI: 10.1007/s12035-015-9562-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 11/29/2015] [Indexed: 02/07/2023]
Abstract
In the brain, astrocytes signal to neighboring cells via regulated exocytotic release of gliosignaling molecules, such as brain-derived neurotrophic factor (BDNF). Recent studies uncovered a role of ketamine, an anesthetic and antidepressant, in the regulation of BDNF expression and in the disruption of astrocytic Ca2+ signaling, but it is unclear whether it affects astroglial BDNF release. We investigated whether ketamine affects ATP-evoked Ca2+ signaling and exocytotic release of BDNF at the single-vesicle level in cultured rat astrocytes. Cells were transfected with a plasmid encoding preproBDNF tagged with the pH-sensitive fluorescent protein superecliptic pHluorin, (BDNF-pHse) to load vesicles and measure the release of BDNF-pHse when the exocytotic fusion pore opens and alkalinizes the luminal pH. In addition, cell-attached membrane capacitance changes were recorded to monitor unitary vesicle interaction with the plasma membrane. Intracellular Ca2+ activity was monitored with Fluo-4 and confocal microscopy, which was also used to immunocytochemically characterize BDNF-pHse-laden vesicles. As revealed by double-fluorescent micrographs, BDNF-pHse localized to vesicles positive for the soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) proteins, vesicle-associated membrane protein 2 (VAMP2), VAMP3, and synaptotagmin IV. Ketamine treatment decreased the number of ATP-evoked BDNF-pHse fusion/secretion events (P < 0.05), the frequency of ATP-evoked transient (P < 0.001) and full-fusion exocytotic (P < 0.05) events, along with a reduction in the ATP-evoked increase in intracellular Ca2+ activity in astrocytes by ~70 % (P < 0.001). The results show that ketamine treatment suppresses ATP-triggered vesicle fusion and BDNF secretion by increasing the probability of a narrow fusion pore open state and/or by reducing astrocytic Ca2+ excitability.
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Affiliation(s)
- Matjaž Stenovec
- Celica Biomedical, Tehnološki park 24, 1000, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000, Ljubljana, Slovenia
| | - Eva Lasič
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000, Ljubljana, Slovenia
| | - Mićo Božić
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000, Ljubljana, Slovenia
| | - Saša Trkov Bobnar
- Celica Biomedical, Tehnološki park 24, 1000, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000, Ljubljana, Slovenia
| | - Randy F Stout
- Department of Neurobiology, Civitan International Research Center and Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, Atomic Force Microscopy and Nanotechnology Laboratories, University of Alabama at Birmingham, 1719 6th Avenue South, CIRC 429, Birmingham, AL, 35294, USA
- The Dominick P. Purpura Department of Neuroscience, Rose F. Kennedy Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Vladimir Grubišić
- Department of Neurobiology, Civitan International Research Center and Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, Atomic Force Microscopy and Nanotechnology Laboratories, University of Alabama at Birmingham, 1719 6th Avenue South, CIRC 429, Birmingham, AL, 35294, USA
- Department of Physiology, Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | - Vladimir Parpura
- Department of Neurobiology, Civitan International Research Center and Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, Atomic Force Microscopy and Nanotechnology Laboratories, University of Alabama at Birmingham, 1719 6th Avenue South, CIRC 429, Birmingham, AL, 35294, USA
| | - Robert Zorec
- Celica Biomedical, Tehnološki park 24, 1000, Ljubljana, Slovenia.
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000, Ljubljana, Slovenia.
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16
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Grubišić V, Parpura V. The second brain in autism spectrum disorder: could connexin 43 expressed in enteric glial cells play a role? Front Cell Neurosci 2015; 9:242. [PMID: 26190971 PMCID: PMC4490256 DOI: 10.3389/fncel.2015.00242] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 06/15/2015] [Indexed: 12/28/2022] Open
Affiliation(s)
- Vladimir Grubišić
- Department of Neurobiology, University of Alabama at Birmingham Birmingham, AL, USA ; Neuroscience Program, Department of Physiology, Michigan State University East Lansing, MI, USA
| | - Vladimir Parpura
- Department of Neurobiology, University of Alabama at Birmingham Birmingham, AL, USA
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17
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Grubišić V, Kennedy AJ, Sweatt JD, Parpura V. Pitt-Hopkins Mouse Model has Altered Particular Gastrointestinal Transits In Vivo. Autism Res 2015; 8:629-33. [PMID: 25728630 DOI: 10.1002/aur.1467] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 02/04/2015] [Indexed: 12/31/2022]
Abstract
Pitt-Hopkins syndrome (PTHS) is a neurodevelopmental disorder, classified as an autism spectrum disorder that is caused by the haploinsufficiency of Transcription Factor 4 (TCF4). The most common non-neurological symptoms in PTHS patients are gastrointestinal (GI) disturbances, mainly gastroesophageal reflux and severe constipation (in about 30 and 75% of PTHS patients, respectively). We hypothesized that the recently recognized mouse model of PTHS will exhibit problems with their gut function. We conducted series of in vivo tests on 15- to 19- week old male mice, heterozygous for the TCF4 functional deletion, mimicking the TCF4 haploinsufficiency in PTHS patients, and their wild type littermates. Data collection and initial analysis were performed blindly, that is, the genotyping key was received after the mean values were calculated for each individual animal, and then mean/median of each group was subsequently calculated. Body weight, fecal pellet output, and fluid content were similar between the groups, indicating normal gross growth of PTHS mice and their overall physiological GI motility and intestinal secretion/absorption. There were no significant differences in gut length and gross appearance pointing out that PTHS mice have normal gut in gross anatomical terms. However, the assessment of gut transit indicates that, while whole-gut transit velocity was similar between the groups, the upper GI and distal colon transit velocities were significantly reduced in the PTHS mice. This is the first evidence of specific gut related problems in the PTHS mice. Our study also validates the TCF4 functional knockout mice as an animal model to study PTHS-associated GI disturbances.
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Affiliation(s)
- Vladimir Grubišić
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Andrew J Kennedy
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - J David Sweatt
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Vladimir Parpura
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama.,Department of Biotechnology, University of Rijeka, Rijeka, Croatia
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18
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Wang Y, Montana V, Grubišić V, Stout RF, Parpura V, Gu LQ. Nanopore sensing of botulinum toxin type B by discriminating an enzymatically cleaved Peptide from a synaptic protein synaptobrevin 2 derivative. ACS Appl Mater Interfaces 2015; 7:184-92. [PMID: 25511125 PMCID: PMC4296922 DOI: 10.1021/am5056596] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Botulinum neurotoxins (BoNTs) are the most lethal toxin known to human. Biodefense requires early and rapid detection of BoNTs. Traditionally, BoNTs can be detected by looking for signs of botulism in mice that receive an injection of human material, serum or stool. While the living animal assay remains the most sensitive approach, it is costly, slow and associated with legal and ethical constrains. Various biochemical, optical and mechanical methods have been developed for BoNTs detection with improved speed, but with lesser sensitivity. Here, we report a novel nanopore-based BoNT type B (BoNT-B) sensor that monitors the toxin's enzymatic activity on its substrate, a recombinant synaptic protein synaptobrevin 2 derivative. By analyzing the modulation of the pore current caused by the specific BoNT-B-digested peptide as a marker, the presence of BoNT-B at a subnanomolar concentration was identified within minutes. The nanopore detector would fill the niche for a much needed rapid and highly sensitive detection of neurotoxins, and provide an excellent system to explore biophysical mechanisms for biopolymer transportation.
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Affiliation(s)
- Yong Wang
- Department
of Bioengineering and Dalton Cardiovascular Research
Center, University of Missouri, Columbia, Missouri 65211, United States
- Dr. Yong Wang. E-mail:
| | - Vedrana Montana
- Department
of Neurobiology, Center for Glial Biology in Medicine,
Atomic Force Microscopy & Nanotechnology Laboratories, Civitan
International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
- Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
| | - Vladimir Grubišić
- Department
of Neurobiology, Center for Glial Biology in Medicine,
Atomic Force Microscopy & Nanotechnology Laboratories, Civitan
International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Randy F. Stout
- Department
of Neurobiology, Center for Glial Biology in Medicine,
Atomic Force Microscopy & Nanotechnology Laboratories, Civitan
International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
- Department of Neuroscience, Albert Einstein
College of Medicine, Bronx, New
York, New York 10461, United States
| | - Vladimir Parpura
- Department
of Neurobiology, Center for Glial Biology in Medicine,
Atomic Force Microscopy & Nanotechnology Laboratories, Civitan
International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
- Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
- Dr. Vladimir Parpura.
E-mail:
| | - Li-Qun Gu
- Department
of Bioengineering and Dalton Cardiovascular Research
Center, University of Missouri, Columbia, Missouri 65211, United States
- Dr. Li-Qun Gu. E-mail:
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Grubišić V, Parpura V. Diversity in the utilization of glucose and lactate in synthetic mammalian myotubes generated by engineered configurations of MyoD and E12 in otherwise non-differentiation growth conditions. Biomaterials 2014; 43:50-60. [PMID: 25591961 DOI: 10.1016/j.biomaterials.2014.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 12/03/2014] [Indexed: 12/21/2022]
Abstract
We previously used the expression of various combinations and configurations of MyoD and E12, two basic helix-loop-helix transcription factors (TF), to produce populations of myotubes assuming distinct morphology, myofibrillar development and Ca2+ dynamics, from mammalian C2C12 myoblasts in non-differentiation growth conditions. Here, we assessed the synthetically generated myotubes in terms of energetics, otherwise necessary to sustain their mechanical output as bio-actuators. We found that the myotubes exhibit changed expression of key regulators for the uptake and utilization of two major cellular fuels, glucose and lactate. Furthermore, while lactate transport was uniformly slowed in all the populations of myotubes, glucose uptake and utilization were modified by particular TF configuration. Our approach allows the production of a class of biomaterials with predetermined energetics that could be applied in biorobotics, where fuel of choice could be used, and also in reparative medicine where, for example, particular population of myotubes could be additionally employed as glucose sinks to mitigate effects of secondary metabolic syndrome.
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Affiliation(s)
- Vladimir Grubišić
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Vladimir Parpura
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia.
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20
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McClain J, Grubišić V, Fried D, Gomez-Suarez RA, Leinninger GM, Sévigny J, Parpura V, Gulbransen BD. Ca2+ responses in enteric glia are mediated by connexin-43 hemichannels and modulate colonic transit in mice. Gastroenterology 2014; 146:497-507.e1. [PMID: 24211490 PMCID: PMC3935238 DOI: 10.1053/j.gastro.2013.10.061] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 10/18/2013] [Accepted: 10/30/2013] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS In the enteric nervous system, neurotransmitters initiate changes in calcium (Ca(2+) responses) in glia, but it is not clear how this process affects intestinal function. We investigated whether Ca(2+)-mediated responses in enteric glia are required to maintain gastrointestinal function. METHODS We used in situ Ca(2+) imaging to monitor glial Ca(2+) responses, which were manipulated with pharmacologic agents or via glia-specific disruption of the gene encoding connexin-43 (Cx43) (hGFAP::CreER(T2+/-)/Cx43(f/f) mice). Gastrointestinal function was assessed based on pellet output, total gut transit, colonic bead expulsion, and muscle tension recordings. Proteins were localized and quantified by immunohistochemistry, immunoblot, and reverse transcription polymerase chain reaction analyses. RESULTS Ca(2+) responses in enteric glia of mice were mediated by Cx43 hemichannels. Cx43 immunoreactivity was confined to enteric glia within the myenteric plexus of the mouse colon; the Cx43 inhibitors carbenoxolone and 43Gap26 inhibited the ability of enteric glia to propagate Ca(2+) responses. In vivo attenuation of Ca(2+) responses in the enteric glial network slowed gut transit overall and delayed colonic transit--these changes are also observed during normal aging. Altered motility with increasing age was associated with reduced glial Ca(2+)-mediated responses and changes in glial expression of Cx43 messenger RNA and protein. CONCLUSIONS Ca(2+)-mediated responses in enteric glia regulate gastrointestinal function in mice. Altered intercellular signaling between enteric glia and neurons might contribute to motility disorders.
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Affiliation(s)
- Jonathon McClain
- Neuroscience Program and Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA
| | - Vladimir Grubišić
- Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy and Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL 35294, USA
| | - David Fried
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824
| | - Roberto A Gomez-Suarez
- Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy and Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL 35294, USA.,Department of Pediatrics Division of Pediatric Gastroenterology Hepatology And Nutrition at Nemours Chlidren's Hospital. Orlando, FL 32827, USA
| | - Gina M Leinninger
- Neuroscience Program and Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA
| | - Jean Sévigny
- Département de microbiologie-infectiologie et d'immunologie, Faculté de Médecine, Université Laval, Québec, QC, Canada.,Centre de recherche du CHU de Québec, Québec, QC, G1V 4G2 Canada
| | - Vladimir Parpura
- Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy and Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL 35294, USA.,Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
| | - Brian D Gulbransen
- Neuroscience Program and Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA
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Grubišić V, Gottipati MK, Stout RF, Grammer JR, Parpura V. Heterogeneity of myotubes generated by the MyoD and E12 basic helix-loop-helix transcription factors in otherwise non-differentiation growth conditions. Biomaterials 2013; 35:2188-98. [PMID: 24360578 DOI: 10.1016/j.biomaterials.2013.11.059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 11/21/2013] [Indexed: 01/06/2023]
Abstract
We used a synthetic biology approach to produce myotubes from mammalian C2C12 myoblasts in non-differentiation growth conditions using the expression of basic helix-loop-helix transcription factors, MyoD and E12, in various combinations and configurations. Our approach not only recapitulated the basics of muscle development and physiology, as the obtained myotubes showed qualities similar to those seen in striated muscle fibers in vivo, but also allowed for the synthesis of populations of myotubes which assumed distinct morphology, myofibrillar development and Ca(2+) dynamics. This fashioned class of biomaterials is suitable for the building blocks of soft actuators in micro-scale biomimetic robotics. This production line strategy can be embraced in reparative medicine as synthetic human myotubes with predetermined morphological/functional properties could be obtained using this very approach. This methodology can be adopted beyond striated muscle for the engineering of other tissue components/cells whose differentiation is governed by the principles of basic helix-loop-helix transcription factors, as in the case, for example, of neural or immune cell types.
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Affiliation(s)
- Vladimir Grubišić
- Department of Neurobiology, University of Alabama, Birmingham, AL 35294, USA
| | - Manoj K Gottipati
- Department of Neurobiology, University of Alabama, Birmingham, AL 35294, USA
| | - Randy F Stout
- Department of Neurobiology, University of Alabama, Birmingham, AL 35294, USA; The Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - J Robert Grammer
- Department of Neurobiology, University of Alabama, Birmingham, AL 35294, USA
| | - Vladimir Parpura
- Department of Neurobiology, University of Alabama, Birmingham, AL 35294, USA; Department of Biotechnology, University or Rijeka, Rijeka 51000, Croatia.
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Stout Jr RF, Grubišić V, Parpura V. A Caenorhabditis elegans locomotion phenotype caused by transgenic repeats of the hlh-17 promoter sequence. PLoS One 2013; 8:e81771. [PMID: 24312354 PMCID: PMC3842965 DOI: 10.1371/journal.pone.0081771] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 10/16/2013] [Indexed: 01/17/2023] Open
Abstract
Transgene technology is one of the most heavily relied upon tools in modern biological research. Expression of an exogenous gene within cells, for research and therapeutic applications, nearly always includes promoters and other regulatory sequences. We found that repeats of a non-protein coding transgenic sequence produced profound changes to the behavior of the nematode Caenorhabditis elegans. These changes were produced by a glial promoter sequence but, unexpectedly, major deficits were observed specifically in backward locomotion, a neuron-driven behavior. We also present evidence that this behavioral phenotype is transpromoter copy number-dependent and manifests early in development and is maintained into adulthood of the worm.
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Affiliation(s)
- Randy F. Stout Jr
- Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy & Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, Alabama, United States of America
| | - Vladimir Grubišić
- Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy & Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, Alabama, United States of America
| | - Vladimir Parpura
- Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy & Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, Alabama, United States of America
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia
- * E-mail:
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Parpura V, Grubišić V, Verkhratsky A. Ca(2+) sources for the exocytotic release of glutamate from astrocytes. Biochim Biophys Acta 2010; 1813:984-91. [PMID: 21118669 DOI: 10.1016/j.bbamcr.2010.11.006] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 11/07/2010] [Accepted: 11/10/2010] [Indexed: 01/26/2023]
Abstract
Astrocytes can exocytotically release the gliotransmitter glutamate from vesicular compartments. Increased cytosolic Ca(2+) concentration is necessary and sufficient for this process. The predominant source of Ca(2+) for exocytosis in astrocytes resides within the endoplasmic reticulum (ER). Inositol 1,4,5-trisphosphate and ryanodine receptors of the ER provide a conduit for the release of Ca(2+) to the cytosol. The ER store is (re)filled by the store-specific Ca(2+)-ATPase. Ultimately, the depleted ER is replenished by Ca(2+) which enters from the extracellular space to the cytosol via store-operated Ca(2+) entry; the TRPC1 protein has been implicated in this part of the astrocytic exocytotic process. Voltage-gated Ca(2+) channels and plasma membrane Na(+)/Ca(2+) exchangers are additional means for cytosolic Ca(2+) entry. Cytosolic Ca(2+) levels can be modulated by mitochondria, which can take up cytosolic Ca(2+) via the Ca(2+) uniporter and release Ca(2+) into cytosol via the mitochondrial Na(+)/Ca(2+) exchanger, as well as by the formation of the mitochondrial permeability transition pore. The interplay between various Ca(2+) sources generates cytosolic Ca(2+) dynamics that can drive Ca(2+)-dependent exocytotic release of glutamate from astrocytes. An understanding of this process in vivo will reveal some of the astrocytic functions in health and disease of the brain. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
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Affiliation(s)
- Vladimir Parpura
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy and Nanotechnology Laboratories, and Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham 35294-0021, USA.
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