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Meliopoulos VA, Marvin SA, Freiden P, Moser LA, Nighot P, Ali R, Blikslager A, Reddivari M, Heath RJ, Koci MD, Schultz-Cherry S. Oral Administration of Astrovirus Capsid Protein Is Sufficient To Induce Acute Diarrhea In Vivo. mBio 2016; 7:e01494-16. [PMID: 27803180 PMCID: PMC5090040 DOI: 10.1128/mbio.01494-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 10/03/2016] [Indexed: 12/27/2022] Open
Abstract
The disease mechanisms associated with the onset of astrovirus diarrhea are unknown. Unlike other enteric virus infections, astrovirus infection is not associated with an inflammatory response or cellular damage. In vitro studies in differentiated Caco-2 cells demonstrated that human astrovirus serotype 1 (HAstV-1) capsid protein alone disrupts the actin cytoskeleton and tight junction complex, leading to increased epithelial barrier permeability. In this study, we show that oral administration of purified recombinant turkey astrovirus 2 (TAstV-2) capsid protein results in acute diarrhea in a dose- and time-dependent manner in turkey poults. Similarly to that induced by infectious virus, TAstV-2 capsid-induced diarrhea was independent of inflammation or histological changes but was associated with increased intestinal barrier permeability, as well as redistribution of sodium hydrogen exchanger 3 (NHE3) from the membrane to the cytoplasm of the intestinal epithelium. Unlike other viral enterotoxins that have been identified, astrovirus capsid induces diarrhea after oral administration, reproducing the natural route of infection and demonstrating that ingestion of intact noninfectious capsid protein may be sufficient to provoke acute diarrhea. Based on these data, we hypothesize that the astrovirus capsid acts like an enterotoxin and induces intestinal epithelial barrier dysfunction. IMPORTANCE Acute gastroenteritis, with its sequela diarrhea, is one of the most important causes of childhood morbidity and mortality worldwide. A variety of infectious agents cause gastroenteritis, and in many cases, an enterotoxin produced by the agent is involved in disease manifestations. Although we commonly think of bacteria as a source of toxins, at least one enteric virus, rotavirus, produces a protein with enterotoxigenic activity during viral replication. In these studies, we demonstrate that oral administration of the turkey astrovirus 2 (TAstV-2) structural (capsid) protein induces acute diarrhea, increases barrier permeability, and causes relocalization of NHE3 in the small intestine, suggesting that rotavirus may not be alone in possessing enterotoxigenic activity.
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Affiliation(s)
- Victoria A Meliopoulos
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Shauna A Marvin
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Pamela Freiden
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Lindsey A Moser
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Prashant Nighot
- Department of Clinical Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Rizwana Ali
- Department of Poultry Science, North Carolina State University, Raleigh, North Carolina, USA
| | - Anthony Blikslager
- Department of Clinical Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Muralidhar Reddivari
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Richard J Heath
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Matthew D Koci
- Department of Poultry Science, North Carolina State University, Raleigh, North Carolina, USA
| | - Stacey Schultz-Cherry
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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Ball JM, Swaggerty CL, Pei X, Lim WS, Xu X, Cox VC, Payne SL. SU proteins from virulent and avirulent EIAV demonstrate distinct biological properties. Virology 2005; 333:132-44. [PMID: 15708599 DOI: 10.1016/j.virol.2004.12.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2004] [Revised: 10/11/2004] [Accepted: 12/17/2004] [Indexed: 10/25/2022]
Abstract
Biologic activity of equine infectious anemia virus (EIAV) surface (SU) glycoprotein was assayed in a mouse model. Recombinant SU from virulent EIAV17 (SU17), administered intraperitoneally to mouse pups, induced dose-dependent diarrheal responses similar to those reported for SIV SU (Virology 277 (2000) 250). SU17 caused fluid accumulation without histological lesions in mouse intestinal loops, induced chloride secretory currents in Ussing chambers and increased inositol 1,4,5 triphosphate (IP3) levels in HT29 cells. An SU17 peptide, SU17(299-330), provoked a dose-dependent diarrheal response akin to enterotoxic peptides from SIV. In contrast, SU from an avirulent EIAV strain failed to induce a dose response in mouse pups and produced lower levels of activity than SU17 in Ussing chambers and IP3 assays. These results demonstrate that a mouse pup model is useful to monitor EIAV SU biologic activity, showing clear differences between the activities of SU derived from virulent and avirulent viruses, and may provide a useful screen of EIAV virulence.
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Affiliation(s)
- J M Ball
- Department of Pathobiology, Texas A&M University, Texas Veterinary Medical Center, MS4467, College Station, TX 77843, USA
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Huang H, Schroeder F, Estes MK, McPherson T, Ball JM. Interaction(s) of rotavirus non-structural protein 4 (NSP4) C-terminal peptides with model membranes. Biochem J 2004; 380:723-33. [PMID: 15012630 PMCID: PMC1224213 DOI: 10.1042/bj20031789] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2003] [Revised: 03/09/2004] [Accepted: 03/10/2004] [Indexed: 01/18/2023]
Abstract
Rotavirus is the major cause of dehydrating gastroenteritis in children and young animals. NSP4 (non-structural protein 4), a rotaviral non-structural glycoprotein and a peptide NSP4(114-135) (DKLTTREIEQVELLKRIYDKLT), corresponding to NSP4 amino acids 114-135, induce diarrhoeal disease in a neonatal mouse model and interact with model membranes that mimic caveolae. Correlation of the mechanisms of diarrhoea induction and membrane interactions by NSP4 protein and peptide remain unclear. Several additional NSP4 peptides were synthesized and their interactions with membranes studied by (i) CD, (ii) a filtration-binding assay and (iii) a fluorescent molecule leakage assay. Model membranes that varied in lipid compositions and radius of curvature were utilized to determine the compositional and structural requirements for optimal interaction with the peptides of NSP4. Similar to the intact protein and NSP4(114-135), peptides overlapping residues 114-135 had significantly higher affinities to membranes rich in negatively charged lipids, rich in cholesterol and with a high radius of curvature. In the leakage assay, small and large unilamellar vesicles loaded with the fluorophore/quencher pair 8-aminonaphthalene-1,3,6-trisulphonic acid disodium salt/p -xylene-bis-pyridinium bromide were incubated with the NSP4 peptides and monitored for membrane disruption by lipid reorganization or by pore formation. At a peptide concentration of 15 microM, none of the NSP4 peptides caused leakage. These results confirm that NSP4 interacts with caveolae-like membranes and the alpha-helical region of NSP4(114-135) comprises a membrane interaction domain that does not induce membrane disruption at physiological concentrations.
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Affiliation(s)
- Huan Huang
- Department of Pharmacology and Physiology, Texas A&M University, TVMC, College Station, TX 77843-4466, USA
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Swaggerty CL, Huang H, Lim WS, Schroeder F, Ball JM. Comparison of SIVmac239(352-382) and SIVsmmPBj41(360-390) enterotoxic synthetic peptides. Virology 2004; 320:243-57. [PMID: 15016547 DOI: 10.1016/j.virol.2003.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2003] [Revised: 11/20/2003] [Accepted: 11/20/2003] [Indexed: 10/26/2022]
Abstract
To characterize the active domain of the simian immunodeficiency virus (SIV) surface unit (SU) enterotoxin, peptides corresponding to the V3 loop of SIVmac239 (SIVmac) and SIVsmmPBj41 (SIVpbj) were synthesized and examined for enterotoxic activity, alpha-helical structure, and interaction(s) with model membranes. SIVmac and SIVpbj induced a dose-dependent diarrhea in 6-8-day-old mouse pups similar to full-length SU. The peptides mobilized [Ca(2+)](i) in HT-29 cells with distinct oscillations and elevated inositol triphosphate levels. Circular dichroism analyses showed the peptides were predominantly random coil in buffer, but increased in alpha-helical content when placed in a hydrophobic environment or with cholesterol-containing membrane vesicles that are rich in anionic phospholipids. None of the peptides underwent significant secondary structural changes in the presence of neutral vesicles indicating ionic interactions were important. These data show that the SIV SU enterotoxic domain localizes in part to the V3 loop region and interacts with anionic membrane domains on the host cell surface.
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Affiliation(s)
- C L Swaggerty
- Department of Pathobiology, College of Veterinary Medicine, Texas A&M University, TAMU 4467, College Station, TX 77843-4467, USA
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Maresca M, Mahfoud R, Garmy N, Kotler DP, Fantini J, Clayton F. The virotoxin model of HIV-1 enteropathy: involvement of GPR15/Bob and galactosylceramide in the cytopathic effects induced by HIV-1 gp120 in the HT-29-D4 intestinal cell line. J Biomed Sci 2003; 10:156-66. [PMID: 12566994 DOI: 10.1007/bf02256007] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2002] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Malabsorption and diarrhea are common, serious problems in AIDS patients, and are in part due to the incompletely understood entity HIV enteropathy. Our prior in vitro work has shown that increased transepithelial permeability and glucose malabsorption, similar to HIV enteropathy, are caused by HIV surface protein gp120, although the mechanism remains unclear. RESULTS We studied the effects of HIV surface protein gp120 on the differentiated intestinal cell line HT-29-D4, specifically the effects on microtubules, transepithelial resistance, and sodium glucose cotransport. gp120 induced extensive microtubule depolymerization, an 80% decrease in transepithelial resistance, and a 70% decrease in sodium-dependent glucose transport, changes closely paralleling those of HIV enteropathy. The effects on transepithelial resistance were used to study potential inhibitors. Neutralizing antibodies to GPR15/Bob but not to CXCR4 (the coreceptor allowing infection with these HIV strains) inhibited these effects. Antibodies to galactosylceramide (GalCer) and a synthetic analog of GalCer also inhibited the gp120-induced changes, suggesting the involvement of GalCer-enriched lipid rafts in gp120 binding to intestinal epithelial cells. CONCLUSION We conclude that direct HIV infection and gp120-induced cytopathic effects are distinct phenomena. While in vivo confirmation is needed to prove this, gp120 could be a virotoxin significantly contributing to HIV enteropathy.
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Affiliation(s)
- Marc Maresca
- Institut Méditerranéen de Recherche en Nutrition, UMR-INRA 1111, Faculté des Sciences de St-Jérôme, Marseille, France
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