Norovirus Infection: Replication, Manipulation of Host, and Interaction with the Host Immune Response

Sarvestani, Soroush T.; Cotton, Ben T; Fritzlar, Svenja; O'Donnell, Tanya B; Mackenzie, Jason M.

doi:10.1089/jir.2015.0124

Cited by 15 publications

(17 citation statements)

References 92 publications

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“…Despite the fact that human noroviruses (HuNVs) are now the leading cause of acute nonbacterial gastroenteritis ( 1 , 7 ), multiple aspects regarding the mechanisms of viral genome replication or viral pathogenesis are still poorly understood. The poor understanding of HuNV replication and pathogenicity is due to the lack of an efficient and reliable cell culture system or an animal system for multicycle replication of HuNV.…”

Section: Introductionmentioning

confidence: 99%

Subcellular Localization and Functional Characterization of GII.4 Norovirus-Encoded NTPase

Yen

Wei

Chen

et al. 2018

J Virol

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The genotype II.4 (GII.4) variants of human noroviruses (HuNVs) are recognized as the major agent of global gastroenteritis outbreaks. Due to the lack of an efficient cell culture system for HuNV propagation, the exact roles of HuNV-encoded nonstructural proteins (including Nterm, NTPase, P22, VPg, Pro, and RdRp) in viral replication or pathogenesis have not yet been fully understood. Here, we report the molecular characterization of the GII.4 HuNV-encoded NTPase (designated GII-NTPase). Results from our studies showed that GII-NTPase forms vesicular or nonvesicular textures in the cell cytoplasm, and the nonvesicular fraction of GII-NTPase significantly localizes to the endoplasmic reticulum (ER) or mitochondria. Deletion analysis revealed that the N-terminal 179-amino-acid (aa) region of GII-NTPase is required for vesicle formation and for ER colocalization, whereas the C-terminal region is involved in mitochondrial colocalization. In particular, two mitochondrion-targeting domains were identified in the C-terminal region of GII-NTPase which perfectly colocalized with mitochondria when the N-terminal region of GII-NTPase was deleted. However, the corresponding C-terminal portions of NTPase derived from the GI HuNV did not show mitochondrial colocalization. We also found that GII-NTPase physically interacts with itself as well as with Nterm and P22, but not VPg, Pro, and RdRp, in cells. The Nterm- and P22-interacting region was mapped to the N-terminal 179-aa region of GII-NTPase, whereas the self-assembly of GII-NTPase could be achieved via a head-to-head, tail-to-tail, or head-to-tail configuration. More importantly, we demonstrate that GII-NTPase possesses a proapoptotic activity, which can be further enhanced by coexpression with Nterm or P22.IMPORTANCE Despite the importance of human norovirus GII.4 variants in global gastroenteritis outbreaks, the basic biological functions of the viral nonstructural proteins in cells remain rarely investigated. In this report, we focus our studies on characteristics of the GII.4 norovirus-encoded NTPase (GII-NTPase). We unexpectedly find that GII-NTPase can perfectly colocalize with mitochondria after its N-terminal region is deleted. However, such a phenomenon is not observed for NTPase encoded by a GI strain. We further reveal that the N-terminal 179-aa region of GII-NTPase is sufficient to mediate (i) vesicle formation, (ii) ER colocalization, (iii) the interaction with two other nonstructural proteins, including Nterm and P22, (iv) the formation of homodimers or homo-oligomers, and (v) the induction of cell apoptosis. Taken together, our findings emphasize that the virus-encoded NTPase must have multiple activities during viral replication or pathogenesis; however, these activities may vary somewhat among different genogroups.

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Section: Introductionmentioning

confidence: 99%

Subcellular Localization and Functional Characterization of GII.4 Norovirus-Encoded NTPase

Yen

Wei

Chen

et al. 2018

J Virol

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“…The clinical symptoms of humans infected with NoV include vomiting, abdominal cramps, and nonbloody loose or watery diarrhea that can lead to severe dehydration (4,5). NoV infections result in an estimated 230,000 deaths per year, particularly in developing nations (6).…”

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confidence: 99%

“…Subsequently, multiple human NoV strains have been more robustly cultivated in stem cell-derived enterocytes forming human intestinal enteroid monolayer cultures (15). Consequently, the molecular mechanisms of human NoV pathogenesis and immunity remain poorly defined (5). In 2003, murine norovirus (MNV) was discovered and has been used to study the immunity and pathogenesis of NoV infection in a mouse model (16).…”

mentioning

confidence: 99%

The Norovirus NS3 Protein Is a Dynamic Lipid- and Microtubule-Associated Protein Involved in Viral RNA Replication

Cotton

Hyde

Sarvestani

et al. 2017

J Virol

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Norovirus (NoV) infections are a significant health burden to society, yet the lack of reliable tissue culture systems has hampered the development of appropriate antiviral therapies. Here we show that the NoV NS3 protein, derived from murine NoV (MNV), is intimately associated with the MNV replication complex and the viral replication intermediate double-stranded RNA (dsRNA). We observed that when expressed individually, MNV NS3 and NS3 encoded by human Norwalk virus (NV) induced the formation of distinct vesicle-like structures that did not colocalize with any particular protein markers to cellular organelles but localized to cellular membranes, in particular those with a high cholesterol content. Both proteins also showed some degree of colocalization with the cytoskeleton marker ␤-tubulin. Although the distribution of MNV and NV NS3s were similar, NV NS3 displayed a higher level of colocalization with the Golgi apparatus and the endoplasmic reticulum (ER). However, we observed that although both proteins colocalized in membranes counterstained with filipin, an indicator of cholesterol content, MNV NS3 displayed a greater association with flotillin and stomatin, proteins known to associate with sphingolipid-and cholesterol-rich microdomains. Utilizing time-lapse epifluorescence microscopy, we observed that the membrane-derived vesicular structures induced by MNV NS3 were highly motile and dynamic in nature, and their movement was dependent on intact microtubules. These results begin to interrogate the functions of NoV proteins during virus replication and highlight the conserved properties of the NoV NS3 proteins among the seven Norovirus genogroups. IMPORTANCE Many mechanisms involved in the replication of norovirus still remain unclear, including the role for the NS3 protein, one of seven nonstructural viral proteins, which remains to be elucidated. This study reveals that murine norovirus (MNV) NS3 is intimately associated with the viral replication complex and dsRNA. We observed that the NS3 proteins of both MNV and Norwalk virus (NV) induce prominent vesicular structures and that this formation is dependent on microtubules and cellular cholesterol. Thus, this study contributes to our understanding of protein function within different Norovirus genogroups and expands a growing knowledge base on the interaction between positive-strand RNA [(ϩ)RNA] viruses and cellular membranes that contribute to the biogenesis of virus-induced membrane organelles. This study contributes to our understanding of viral protein function and the ability of a viral protein to recruit specific cellular organelles and lipids that enable replication.KEYWORDS norovirus, cytoskeleton, virus replication, cellular lipids

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“…The replication of noroviruses has been exhaustively reviewed elsewhere [ 7 , 8 , 16 ], and will be discussed briefly here, as many of the approaches to designing anti-norovirus molecules target various stages of the virus replication process. Noroviruses attach to host cells through the interactions between the VP1 and the host HBGA oligosaccharide receptors [ 10 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

Therapeutics and Immunoprophylaxis Against Noroviruses and Rotaviruses: The Past, Present, and Future

Ghosh

Malik

Kobayashi

2018

CDM

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Background: Noroviruses and rotaviruses are important viral etiologies of severe gastroenteritis. Noroviruses are the primary cause of nonbacterial diarrheal outbreaks in humans, whilst rotaviruses are a major cause of childhood diarrhea. Although both enteric pathogens substantially impact human health and economies, there are no approved drugs against noroviruses and rotaviruses so far. On the other hand, whilst the currently licensed rotavirus vaccines have been successfully implemented in over 100 countries, the most advanced norovirus vaccine has recently completed phase-I and II trials.Methods: We performed a structured search of bibliographic databases for peer-reviewed research litera-ture on advances in the fields of norovirus and rotavirus therapeutics and immunoprophylaxis.Results: Technological advances coupled with a proper understanding of viral morphology and replication over the past decade has facilitated pioneering research on therapeutics and immunoprophylaxis against noroviruses and rotaviruses, with promising outcomes in human clinical trials of some of the drugs and vaccines. This review focuses on the various developments in the fields of norovirus and rotavirus thera-peutics and immunoprophylaxis, such as potential antiviral drug molecules, passive immunotherapies (oral human immunoglobulins, egg yolk and bovine colostral antibodies, llama-derived nanobodies, and anti-bodies expressed in probiotics, plants, rice grains and insect larvae), immune system modulators, probiot-ics, phytochemicals and other biological substances such as bovine milk proteins, therapeutic nanoparti-cles, hydrogels and viscogens, conventional viral vaccines (live and inactivated whole virus vaccines), and genetically engineered viral vaccines (reassortant viral particles, virus-like particles (VLPs) and other sub-unit recombinant vaccines including multi-valent viral vaccines, edible plant vaccines, and encapsulated viral particles).Conclusions: This review provides important insights into the various approaches to therapeutics and im-munoprophylaxis against noroviruses and rotaviruses..

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Norovirus Infection: Replication, Manipulation of Host, and Interaction with the Host Immune Response

Cited by 15 publications

References 92 publications

Subcellular Localization and Functional Characterization of GII.4 Norovirus-Encoded NTPase

Subcellular Localization and Functional Characterization of GII.4 Norovirus-Encoded NTPase

The Norovirus NS3 Protein Is a Dynamic Lipid- and Microtubule-Associated Protein Involved in Viral RNA Replication

Therapeutics and Immunoprophylaxis Against Noroviruses and Rotaviruses: The Past, Present, and Future

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