Publications by authors named "Christiane E Wobus"

95 Publications

Macrophage inflammatory state influences susceptibility to lysosomal damage.

J Leukoc Biol 2021 Jul 14. Epub 2021 Jul 14.

Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA.

Macrophages possess mechanisms for reinforcing the integrity of their endolysosomes against damage. This property, termed inducible renitence, was previously observed in murine macrophages stimulated with LPS, peptidoglycan, IFNγ, or TNFα, which suggested roles for renitence in macrophage resistance to infection by membrane-damaging pathogens. This study analyzed additional inducers of macrophage differentiation for their ability to increase resistance to lysosomal damage by membrane-damaging particles. Renitence was evident in macrophages activated with LPS plus IFNγ, PGE , or adenosine, and in macrophages stimulated with IFN-β, but not in macrophages activated with IL-4 or IL-10. These responses indicated roles for macrophage subtypes specialized in host defense and suppression of immune responses, but not those involved in wound healing. Consistent with this pattern, renitence could be induced by stimulation with agonists for TLR, which required the signaling adaptors MyD88 and/or TRIF, and by infection with murine norovirus-1. Renitence induced by LPS was dependent on cytokine secretion by macrophages. However, no single secreted factor could explain all the induced responses. Renitence induced by the TLR3 agonist Poly(I:C) was mediated in part by the type I IFN response, but renitence induced by Pam3CSK4 (TLR2/1), LPS (TLR4), IFNγ, or TNFα was independent of type 1 IFN signaling. Thus, multiple pathways for inducing macrophage resistance to membrane damage exist and depend on the particular microbial stimulus sensed.
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http://dx.doi.org/10.1002/JLB.3A0520-325RRDOI Listing
July 2021

Comparative Analysis of Public RNA-Sequencing Data from Human Intestinal Enteroid (HIEs) Infected with Enteric RNA Viruses Identifies Universal and Virus-Specific Epithelial Responses.

Viruses 2021 Jun 3;13(6). Epub 2021 Jun 3.

Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA.

Acute gastroenteritis (AGE) has a significant disease burden on society. Noroviruses, rotaviruses, and astroviruses are important viral causes of AGE but are relatively understudied enteric pathogens. Recent developments in novel biomimetic human models of enteric disease are opening new possibilities for studying human-specific host-microbe interactions. Human intestinal enteroids (HIE), which are epithelium-only intestinal organoids derived from stem cells isolated from human intestinal biopsy tissues, have been successfully used to culture representative norovirus, rotavirus, and astrovirus strains. Previous studies investigated host-virus interactions at the intestinal epithelial interface by individually profiling the epithelial transcriptional response to a member of each virus family by RNA sequencing (RNA-seq). Despite differences in the tissue origin, enteric virus used, and hours post infection at which RNA was collected in each data set, the uniform analysis of publicly available datasets identified a conserved epithelial response to virus infection focused around "type I interferon production" and interferon-stimulated genes. Additionally, transcriptional changes specific to only one or two of the enteric viruses were also identified. This study can guide future explorations into common and unique aspects of the host response to virus infections in the human intestinal epithelium and demonstrates the promise of comparative RNA-seq analysis, even if performed under different experimental conditions, to discover universal and virus-specific genes and pathways responsible for antiviral host defense.
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http://dx.doi.org/10.3390/v13061059DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8227290PMC
June 2021

Identification of ACE2 modifiers by CRISPR screening.

bioRxiv 2021 Jun 10. Epub 2021 Jun 10.

SARS-CoV-2 infection is initiated by binding of the viral spike protein to its receptor, ACE2, on the surface of host cells. ACE2 expression is heterogeneous both and in immortalized cell lines, but the molecular pathways that govern ACE2 expression remain unclear. We now report high-throughput CRISPR screens for functional modifiers of ACE2 surface abundance. We identified 35 genes whose disruption was associated with a change in the surface abundance of ACE2 in HuH7 cells. Enriched among these ACE2 regulators were established transcription factors, epigenetic regulators, and functional networks. We further characterized individual cell lines with disruption of , or and found these genes to regulate ACE2 at the mRNA level and to influence cellular susceptibility to SARS-CoV-2 infection. Collectively, our findings clarify the host factors involved in SARS-CoV-2 entry and suggest potential targets for therapeutic development.
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http://dx.doi.org/10.1101/2021.06.10.447768DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8202422PMC
June 2021

Salmonella enterica Serovar Typhimurium SPI-1 and SPI-2 Shape the Global Transcriptional Landscape in a Human Intestinal Organoid Model System.

mBio 2021 05 18;12(3). Epub 2021 May 18.

Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA

The intestinal epithelium is a primary interface for engagement of the host response by foodborne pathogens, like Typhimurium. While the interaction of Typhimurium with the mammalian host has been well studied in transformed epithelial cell lines or in the complex intestinal environment , few tractable models recapitulate key features of the intestine. Human intestinal organoids (HIOs) contain a polarized epithelium with functionally differentiated cell subtypes, including enterocytes and goblet cells and a supporting mesenchymal cell layer. HIOs contain luminal space that supports bacterial replication, are more amenable to experimental manipulation than animals and are more reflective of physiological host responses. Here, we use the HIO model to define host transcriptional responses to Typhimurium infection, also determining host pathways dependent on pathogenicity island-1 (SPI-1)- and -2 (SPI-2)-encoded type 3 secretion systems (T3SS). Consistent with prior findings, we find that Typhimurium strongly stimulates proinflammatory gene expression. Infection-induced cytokine gene expression was rapid, transient, and largely independent of SPI-1 T3SS-mediated invasion, likely due to continued luminal stimulation. Notably, Typhimurium infection led to significant downregulation of host genes associated with cell cycle and DNA repair, leading to a reduction in cellular proliferation, dependent on SPI-1 and SPI-2 T3SS. The transcriptional profile of cell cycle-associated target genes implicates multiple miRNAs as mediators of Typhimurium-dependent cell cycle suppression. These findings from -infected HIOs delineate common and distinct contributions of SPI-1 and SPI-2 T3SSs in inducing early host responses during enteric infection and reinforce host cell proliferation as a process targeted by serovar Typhimurium ( Typhimurium) causes a significant health burden worldwide, yet host responses to initial stages of intestinal infection remain poorly understood. Due to differences in infection outcome between mice and humans, physiological human host responses driven by major virulence determinants of have been more challenging to evaluate. Here, we use the three-dimensional human intestinal organoid model to define early responses to infection with wild-type Typhimurium and mutants defective in the SPI-1 or SPI-2 type-3 secretion systems. While both secretion system mutants show defects in mouse models of oral infection, the specific contributions of each secretion system are less well understood. We show that Typhimurium upregulates proinflammatory pathways independently of either secretion system, while the downregulation of the host cell cycle pathways relies on both SPI-1 and SPI-2. These findings lay the groundwork for future studies investigating how SPI-1- and SPI-2-driven host responses affect infection outcome and show the potential of this model to study host-pathogen interactions with other serovars to understand how initial interactions with the intestinal epithelium may affect pathogenesis.
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http://dx.doi.org/10.1128/mBio.00399-21DOI Listing
May 2021

Host-Virus Chimeric Events in SARS-CoV-2-Infected Cells Are Infrequent and Artifactual.

J Virol 2021 07 12;95(15):e0029421. Epub 2021 Jul 12.

Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA.

The pathogenic mechanisms underlying severe SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection remain largely unelucidated. High-throughput sequencing technologies that capture genome and transcriptome information are key approaches to gain detailed mechanistic insights from infected cells. These techniques readily detect both pathogen- and host-derived sequences, providing a means of studying host-pathogen interactions. Recent studies have reported the presence of host-virus chimeric (HVC) RNA in transcriptome sequencing (RNA-seq) data from SARS-CoV-2-infected cells and interpreted these findings as evidence of viral integration in the human genome as a potential pathogenic mechanism. Since SARS-CoV-2 is a positive-sense RNA virus that replicates in the cytoplasm, it does not have a nuclear phase in its life cycle. Thus, it is biologically unlikely to be in a location where splicing events could result in genome integration. Therefore, we investigated the biological authenticity of HVC events. In contrast to true biological events like mRNA splicing and genome rearrangement events, which generate reproducible chimeric sequencing fragments across different biological isolates, we found that HVC events across >100 RNA-seq libraries from patients with coronavirus disease 2019 (COVID-19) and infected cell lines were highly irreproducible. RNA-seq library preparation is inherently error prone due to random template switching during reverse transcription of RNA to cDNA. By counting chimeric events observed when constructing an RNA-seq library from human RNA and spiked-in RNA from an unrelated species, such as the fruit fly, we estimated that ∼1% of RNA-seq reads are artifactually chimeric. In SARS-CoV-2 RNA-seq, we found that the frequency of HVC events was, in fact, not greater than this background "noise." Finally, we developed a novel experimental approach to enrich SARS-CoV-2 sequences from bulk RNA of infected cells. This method enriched viral sequences but did not enrich HVC events, suggesting that the majority of HVC events are, in all likelihood, artifacts of library construction. In conclusion, our findings indicate that HVC events observed in RNA-sequencing libraries from SARS-CoV-2-infected cells are extremely rare and are likely artifacts arising from random template switching of reverse transcriptase and/or sequence alignment errors. Therefore, the observed HVC events do not support SARS-CoV-2 fusion to cellular genes and/or integration into human genomes. The pathogenic mechanisms underlying SARS-CoV-2, the virus responsible for COVID-19, are not fully understood. In particular, relatively little is known about the reasons some individuals develop life-threatening or persistent COVID-19. Recent studies identified host-virus chimeric (HVC) reads in RNA-sequencing data from SARS-CoV-2-infected cells and suggested that HVC events support potential "human genome invasion" and "integration" by SARS-CoV-2. This suggestion has fueled concerns about the long-term effects of current mRNA vaccines that incorporate elements of the viral genome. SARS-CoV-2 is a positive-sense, single-stranded RNA virus that does not encode a reverse transcriptase and does not include a nuclear phase in its life cycle, so some doubts have rightfully been expressed regarding the authenticity of HVCs and the role played by endogenous retrotransposons in this phenomenon. Thus, it is important to independently authenticate these HVC events. Here, we provide several lines of evidence suggesting that the observed HVC events are likely artifactual.
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http://dx.doi.org/10.1128/JVI.00294-21DOI Listing
July 2021

A Norovirus Uses Bile Salts To Escape Antibody Recognition While Enhancing Receptor Binding.

J Virol 2021 Jun 10;95(13):e0017621. Epub 2021 Jun 10.

University of Texas Medical Branch at Galveston, Department of Biochemistry and Molecular Biology, Galveston, Texas, USA.

Noroviruses, members of the family, are the major cause of epidemic gastroenteritis in humans, causing ∼20 million cases annually. These plus-strand RNA viruses have T=3 icosahedral protein capsids with 90 pronounced protruding (P) domain dimers to which antibodies and cellular receptors bind. In the case of mouse norovirus (MNV), bile salts have been shown to enhance receptor (CD300lf) binding to the P domain. We demonstrated previously that the P domains of several genotypes are markedly flexible and "float" over the shell, but the role of this flexibility was unclear. Recently, we demonstrated that bile causes a 90° rotation and collapse of the P domain onto the shell surface. Since bile binds distally to the P-shell interface, it was not at all clear how it could cause such dramatic changes. Here, we present the near-atomic resolution cryo-electron microscopy (cryo-EM) structure of the MNV protruding domain complexed with a neutralizing Fab. On the basis of previous results, we show here that bile salts cause allosteric conformational changes in the P domain that block antibody recognition of the top of the P domain. In addition, bile causes a major rearrangement of the P domain dimers that is likely responsible for the bile-induced collapse of the P domain onto the shell. In the contracted shell conformation, antibodies to the P1 and shell domains are not expected to bind. Therefore, at the site of infection in the gut, the host's own bile allows the virus to escape antibody-mediated neutralization while enhancing cell attachment. The major feature of calicivirus capsids is the 90 protruding domains (P domains) that are the site of cell receptor attachment and antibody epitopes. We demonstrated previously that these P domains are highly mobile and that bile causes these "floating" P domains in mouse norovirus (MNV) to contract onto the shell surface. Here, we present the near-atomic cryo-EM structure of the isolated MNV P domain complexed with a neutralizing Fab fragment. Our data show that bile causes two sets of changes. First, bile causes allosteric conformational changes in the epitopes at the top of the P domain that block antibody binding. Second, bile causes the P domain dimer subunits to rotate relative to each other, causing a contraction of the P domain that buries epitopes at the base of the P and shell domains. Taken together, the results show that MNV uses the host's own metabolites to enhance cell receptor binding while simultaneously blocking antibody recognition.
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http://dx.doi.org/10.1128/JVI.00176-21DOI Listing
June 2021

SARS-CoV-2 drives JAK1/2-dependent local complement hyperactivation.

Sci Immunol 2021 04;6(58)

Department of Biochemistry, Purdue University, West Lafayette, IN, USA.

Patients with coronavirus disease 2019 (COVID-19) present a wide range of acute clinical manifestations affecting the lungs, liver, kidneys and gut. Angiotensin converting enzyme (ACE) 2, the best-characterized entry receptor for the disease-causing virus SARS-CoV-2, is highly expressed in the aforementioned tissues. However, the pathways that underlie the disease are still poorly understood. Here, we unexpectedly found that the complement system was one of the intracellular pathways most highly induced by SARS-CoV-2 infection in lung epithelial cells. Infection of respiratory epithelial cells with SARS-CoV-2 generated activated complement component C3a and could be blocked by a cell-permeable inhibitor of complement factor B (CFBi), indicating the presence of an inducible cell-intrinsic C3 convertase in respiratory epithelial cells. Within cells of the bronchoalveolar lavage of patients, distinct signatures of complement activation in myeloid, lymphoid and epithelial cells tracked with disease severity. Genes induced by SARS-CoV-2 and the drugs that could normalize these genes both implicated the interferon-JAK1/2-STAT1 signaling system and NF-κB as the main drivers of their expression. Ruxolitinib, a JAK1/2 inhibitor, normalized interferon signature genes and all complement gene transcripts induced by SARS-CoV-2 in lung epithelial cell lines, but did not affect NF-κB-regulated genes. Ruxolitinib, alone or in combination with the antiviral remdesivir, inhibited C3a protein produced by infected cells. Together, we postulate that combination therapy with JAK inhibitors and drugs that normalize NF-κB-signaling could potentially have clinical application for severe COVID-19.
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http://dx.doi.org/10.1126/sciimmunol.abg0833DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8139422PMC
April 2021

Host-virus chimeric events in SARS-CoV2 infected cells are infrequent and artifactual.

bioRxiv 2021 Feb 17. Epub 2021 Feb 17.

Department of Biochemistry, Purdue University, West Lafayette, IN, USA.

Pathogenic mechanisms underlying severe SARS-CoV2 infection remain largely unelucidated. High throughput sequencing technologies that capture genome and transcriptome information are key approaches to gain detailed mechanistic insights from infected cells. These techniques readily detect both pathogen and host-derived sequences, providing a means of studying host-pathogen interactions. Recent studies have reported the presence of host-virus chimeric (HVC) RNA in RNA-seq data from SARS-CoV2 infected cells and interpreted these findings as evidence of viral integration in the human genome as a potential pathogenic mechanism. Since SARS-CoV2 is a positive sense RNA virus that replicates in the cytoplasm it does not have a nuclear phase in its life cycle, it is biologically unlikely to be in a location where splicing events could result in genome integration. Here, we investigated the biological authenticity of HVC events. In contrast to true biological events such as mRNA splicing and genome rearrangement events, which generate reproducible chimeric sequencing fragments across different biological isolates, we found that HVC events across >100 RNA-seq libraries from patients with COVID-19 and infected cell lines, were highly irreproducible. RNA-seq library preparation is inherently error-prone due to random template switching during reverse transcription of RNA to cDNA. By counting chimeric events observed when constructing an RNA-seq library from human RNA and spike-in RNA from an unrelated species, such as fruit-fly, we estimated that ~1% of RNA-seq reads are artifactually chimeric. In SARS-CoV2 RNA-seq we found that the frequency of HVC events was, in fact, not greater than this background "noise". Finally, we developed a novel experimental approach to enrich SARS-CoV2 sequences from bulk RNA of infected cells. This method enriched viral sequences but did not enrich for HVC events, suggesting that the majority of HVC events are, in all likelihood, artifacts of library construction. In conclusion, our findings indicate that HVC events observed in RNA-sequencing libraries from SARS-CoV2 infected cells are extremely rare and are likely artifacts arising from either random template switching of reverse-transcriptase and/or sequence alignment errors. Therefore, the observed HVC events do not support SARS-CoV2 fusion to cellular genes and/or integration into human genomes.
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http://dx.doi.org/10.1101/2021.02.17.431704DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7899447PMC
February 2021

Egress of non-enveloped enteric RNA viruses.

J Gen Virol 2021 03 9;102(3). Epub 2021 Feb 9.

Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620, USA.

A long-standing paradigm in virology was that non-enveloped viruses induce cell lysis to release progeny virions. However, emerging evidence indicates that some non-enveloped viruses exit cells without inducing cell lysis, while others engage both lytic and non-lytic egress mechanisms. Enteric viruses are transmitted via the faecal-oral route and are important causes of a wide range of human infections, both gastrointestinal and extra-intestinal. Virus cellular egress, when fully understood, may be a relevant target for antiviral therapies, which could minimize the public health impact of these infections. In this review, we outline lytic and non-lytic cell egress mechanisms of non-enveloped enteric RNA viruses belonging to five families: , , , and . We discuss factors that contribute to egress mechanisms and the relevance of these mechanisms to virion stability, infectivity and transmission. Since most data were obtained in traditional two-dimensional cell cultures, we will further attempt to place them into the context of polarized cultures and pathogenesis. Throughout the review, we highlight numerous knowledge gaps to stimulate future research into the egress mechanisms of these highly prevalent but largely understudied viruses.
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http://dx.doi.org/10.1099/jgv.0.001557DOI Listing
March 2021

Prolonged Severe Acute Respiratory Syndrome Coronavirus 2 Replication in an Immunocompromised Patient.

J Infect Dis 2021 01;223(1):23-27

Division of Infectious Diseases, University of Michigan, Ann Arbor, Michigan, USA.

We describe a case of chronic coronavirus disease 2019 (COVID-19) in a patient with lymphoma and associated B-cell immunodeficiency. Viral cultures and sequence analysis demonstrate ongoing replication of infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for at least 119 days. The patient had 3 admissions related to COVID-19 over a 4-month period and was treated twice with remdesivir and convalescent plasma with resolution of symptoms. The patient's lack of seroconversion and prolonged course illustrate the importance of humoral immunity in resolving SARS-CoV-2 infection. This case highlights challenges in managing immunocompromised hosts, who may act as persistent shedders and sources of transmission.
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http://dx.doi.org/10.1093/infdis/jiaa666DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7797758PMC
January 2021

SARS-CoV-2 receptor networks in diabetic and COVID-19-associated kidney disease.

Kidney Int 2020 12 8;98(6):1502-1518. Epub 2020 Oct 8.

Chronic Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona, USA.

COVID-19 morbidity and mortality are increased via unknown mechanisms in patients with diabetes and kidney disease. SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE2) for entry into host cells. Because ACE2 is a susceptibility factor for infection, we investigated how diabetic kidney disease and medications alter ACE2 receptor expression in kidneys. Single cell RNA profiling of kidney biopsies from healthy living donors and patients with diabetic kidney disease revealed ACE2 expression primarily in proximal tubular epithelial cells. This cell-specific localization was confirmed by in situ hybridization. ACE2 expression levels were unaltered by exposures to renin-angiotensin-aldosterone system inhibitors in diabetic kidney disease. Bayesian integrative analysis of a large compendium of public -omics datasets identified molecular network modules induced in ACE2-expressing proximal tubular epithelial cells in diabetic kidney disease (searchable at hb.flatironinstitute.org/covid-kidney) that were linked to viral entry, immune activation, endomembrane reorganization, and RNA processing. The diabetic kidney disease ACE2-positive proximal tubular epithelial cell module overlapped with expression patterns seen in SARS-CoV-2-infected cells. Similar cellular programs were seen in ACE2-positive proximal tubular epithelial cells obtained from urine samples of 13 hospitalized patients with COVID-19, suggesting a consistent ACE2-coregulated proximal tubular epithelial cell expression program that may interact with the SARS-CoV-2 infection processes. Thus SARS-CoV-2 receptor networks can seed further research into risk stratification and therapeutic strategies for COVID-19-related kidney damage.
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http://dx.doi.org/10.1016/j.kint.2020.09.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7543950PMC
December 2020

Performic Acid Disinfection of Municipal Secondary Effluent Wastewater: Inactivation of Murine Norovirus, Fecal Coliforms, and Enterococci.

Environ Sci Technol 2020 10 8;54(19):12761-12770. Epub 2020 Sep 8.

Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario N6A 5B9, Canada.

Performic acid (PFA) is an emerging disinfectant to inactivate bacterial and viral microorganisms in wastewater. In this study, the inactivation kinetics of murine norovirus (MNV) by PFA, in phosphate buffer and municipal secondary effluent wastewater, are reported for the first time. PFA decay followed first-order kinetics and the inactivation of MNV was governed by the exposure of microorganisms to PFA, i.e., the integral of the PFA concentration over time (integral CT or ICT). The extension of the Chick-Watson model, in the ICT domain, described well the reduction of MNV by PFA, with determined ICT-based inactivation rate constants, , of 1.024 ± 0.038 L/(mg·min) and 0.482 ± 0.022 L/(mg·min) in phosphate buffer and wastewater, respectively, at pH 7.2. Furthermore, the simultaneous PFA inactivation of MNV and fecal indicators indigenously present in wastewater such as fecal coliforms and enterococci showed that 1-log reduction could be achieved with ICT of 2, 1.5, and 3.5 mg·min/L, respectively. When compared with the most commonly used peracid disinfectant of municipal wastewater, peracetic acid (PAA), the ICT requirements determined using the fitted ICT-based kinetic models were ∼20 times higher for PAA than PFA, indicating a much stronger inactivation power of the PFA molecule.
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http://dx.doi.org/10.1021/acs.est.0c05144DOI Listing
October 2020

CD300LF Polymorphisms of Inbred Mouse Strains Confer Resistance to Murine Norovirus Infection in a Cell Type-Dependent Manner.

J Virol 2020 08 17;94(17). Epub 2020 Aug 17.

Committee on Microbiology, The University of Chicago, Chicago, Illinois, USA

Human norovirus is the leading cause of gastroenteritis worldwide, yet basic questions about its life cycle remain unanswered due to an historical lack of robust experimental systems. Recent studies on the closely related murine norovirus (MNV) have identified CD300LF as an indispensable entry factor for MNV. We compared the MNV susceptibilities of cells from different mouse strains and identified polymorphisms in murine CD300LF which are critical for its function as an MNV receptor. Bone marrow-derived macrophages (BMDMs) from I/LnJ mice were resistant to infection from multiple MNV strains which readily infect BMDMs from C57BL/6J mice. The resistance of I/LnJ BMDMs was specific to MNV, since the cells supported infection of other viruses comparably to C57BL/6J BMDMs. Transduction of I/LnJ BMDMs with C57BL/6J CD300LF made the cells permissible to MNV infection, suggesting that the cause of resistance lies in the entry step of MNV infection. In fact, we mapped this phenotype to a 4-amino-acid difference at the CC' loop of CD300LF; swapping of these amino acids between C57BL/6J and I/LnJ CD300LF proteins made the mutant C57BL/6J CD300LF functionally impaired and the corresponding mutant of I/LnJ CD300LF functional as an MNV entry factor. Surprisingly, expression of the I/LnJ CD300LF in other cell types made the cells infectible by MNV, even though the I/LnJ allele did not function as an MNV receptor in macrophage-like cells. Correspondingly, I/LnJ CD300LF bound MNV virions in permissive cells but not in nonpermissive cells. Collectively, our data suggest the existence of a cell type-specific modifier of MNV entry. MNV is a prevalent model system for studying human norovirus, which is the leading cause of gastroenteritis worldwide and thus a sizeable public health burden. Elucidating mechanisms underlying susceptibility of host cells to MNV infection can lead to insights on the roles that specific cell types play during norovirus pathogenesis. Here, we show that different alleles of the proteinaceous receptor for MNV, CD300LF, function in a cell type-dependent manner. In contrast to the C57BL/6J allele, which functions as an MNV entry factor in all tested cell types, including human cells, I/LnJ CD300LF does not function as an MNV entry factor in macrophage-like cells but does allow MNV entry in other cell types. Together, these observations indicate the existence of cell type-specific modifiers of CD300LF-dependent MNV entry.
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http://dx.doi.org/10.1128/JVI.00837-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7431780PMC
August 2020

Morphological Cell Profiling of SARS-CoV-2 Infection Identifies Drug Repurposing Candidates for COVID-19.

bioRxiv 2020 Jun 10. Epub 2020 Jun 10.

Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109, USA.

The global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the associated disease COVID-19, requires therapeutic interventions that can be rapidly translated to clinical care. Unfortunately, traditional drug discovery methods have a >90% failure rate and can take 10-15 years from target identification to clinical use. In contrast, drug repurposing can significantly accelerate translation. We developed a quantitative high-throughput screen to identify efficacious single agents and combination therapies against SARS-CoV-2. Quantitative high-content morphological profiling was coupled with an AI-based machine learning strategy to classify features of cells for infection and stress. This assay detected multiple antiviral mechanisms of action (MOA), including inhibition of viral entry, propagation, and modulation of host cellular responses. From a library of 1,425 FDA-approved compounds and clinical candidates, we identified 16 dose-responsive compounds with antiviral effects. In particular, we discovered that lactoferrin is an effective inhibitor of SARS-CoV-2 infection with an IC of 308 nM and that it potentiates the efficacy of both remdesivir and hydroxychloroquine. Lactoferrin also stimulates an antiviral host cell response and retains inhibitory activity in iPSC-derived alveolar epithelial cells, a model for the primary site of infection. Given its safety profile in humans, these data suggest that lactoferrin is a readily translatable therapeutic adjunct for COVID-19. Additionally, several commonly prescribed drugs were found to exacerbate viral infection and warrant clinical investigation. We conclude that morphological profiling for drug repurposing is an effective strategy for the selection and optimization of drugs and drug combinations as viable therapeutic options for COVID-19 pandemic and other emerging infectious diseases.
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http://dx.doi.org/10.1101/2020.05.27.117184DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7302203PMC
June 2020

Norovirus infection causes acute self-resolving diarrhea in wild-type neonatal mice.

Nat Commun 2020 06 11;11(1):2968. Epub 2020 Jun 11.

Department of Molecular Genetics & Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA.

Human noroviruses are the leading cause of severe childhood diarrhea worldwide, yet we know little about their pathogenic mechanisms. Murine noroviruses cause diarrhea in interferon-deficient adult mice but these hosts also develop systemic pathology and lethality, reducing confidence in the translatability of findings to human norovirus disease. Herein we report that a murine norovirus causes self-resolving diarrhea in the absence of systemic disease in wild-type neonatal mice, thus mirroring the key features of human norovirus disease and representing a norovirus small animal disease model in wild-type mice. Intriguingly, lymphocytes are critical for controlling acute norovirus replication while simultaneously contributing to disease severity, likely reflecting their dual role as targets of viral infection and key components of the host response.
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http://dx.doi.org/10.1038/s41467-020-16798-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7289885PMC
June 2020

Infectious Norovirus Is Chronically Shed by Immunocompromised Pediatric Hosts.

Viruses 2020 06 5;12(6). Epub 2020 Jun 5.

Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.

Noroviruses are a leading cause of gastroenteritis worldwide. Although infections in healthy individuals are self-resolving, immunocompromised individuals are at risk for chronic disease and severe complications. Chronic norovirus infections in immunocompromised hosts are often characterized by long-term virus shedding, but it is unclear whether this shed virus remains infectious. We investigated the prevalence, genetic heterogeneity, and temporal aspects of norovirus infections in 1140 patients treated during a 6-year period at a pediatric research hospital. Additionally, we identified 20 patients with chronic infections lasting 37 to >418 days. Using a new human norovirus in vitro assay, we confirmed the continuous shedding of infectious virus for the first time. Shedding lasted longer in male patients and those with diarrheal symptoms. Prolonged shedding of infectious norovirus in immunocompromised hosts can potentially increase the likelihood of transmission, highlighting the importance of isolation precautions to prevent nosocomial infections.
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http://dx.doi.org/10.3390/v12060619DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7354526PMC
June 2020

SARS-CoV-2 receptor networks in diabetic kidney disease, BK-Virus nephropathy and COVID-19 associated acute kidney injury.

medRxiv 2020 May 13. Epub 2020 May 13.

COVID-19 morbidity and mortality is significantly increased in patients with diabetes and kidney disease via unknown mechanisms. SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE2) for entry into human host cells, and ACE2 levels in target cells may influence SARS-CoV-2 susceptibility. We investigated how pre-existing conditions and drug treatments alter receptor expression in kidney tissue. Using single cell RNA profiling (scRNAseq) to assess ACE2 and associated SARS-CoV-2 proteases in healthy living donors (LD) kidneys, diabetic kidney disease (DKD), and in kidney injury during viral infection, ACE2 expression was primarily associated with proximal tubular epithelial cells (PTEC). ACE2 mRNA expression levels were significantly upregulated in DKD versus LD, however, ACE2 levels were not altered by exposures to renin angiotensin aldosterone system (RAAS) inhibitors. ACE2+ expression signatures were defined by differential expression analysis and characterized by Bayesian integrative analysis of a large compendium of public -omics datasets, resulting in the identification of network modules induced in ACE2 positive PTEC in DKD and BK virus nephropathy. These ACE2 upregulated cell programs were linked to viral entry, immune activation, endomembrane reorganization, and RNA processing and overlapped significantly with the cellular responses induced by SARS-CoV-2 infection. Similar cellular programs were activated in ACE2-positive PTEC isolated in a urine sample from a COVID19 patient with acute kidney injury, suggesting a consistent ACE2-coregulated expression program that may interact with SARS-Cov-2 infection processes. The SARS-CoV-2 receptor associated gene signatures could seed further research into therapeutic strategies for COVID-19. Functional networks of gene expression signatures are available for further exploration to researchers at HumanBase (hb.flatironinstitute.org/covid-kidney).
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http://dx.doi.org/10.1101/2020.05.09.20096511DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7241118PMC
May 2020

Antiviral effects of bovine lactoferrin on human norovirus.

Biochem Cell Biol 2021 02 29;99(1):166-172. Epub 2020 Apr 29.

Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48130, USA.

Human noroviruses cause significant morbidity and mortality worldwide, but lack approved antivirals or vaccines to treat or prevent infections. The recent development of two cell culture systems in human transformed B cells (BJABs) and non-transformed human intestinal enteroid cultures overcomes a main limitation in identifying molecules with anti-norovirus activities. Lactoferrin is an iron-binding glycoprotein found in the milk of most mammals, with broad spectrum antimicrobial activities, including against the related murine norovirus in cell culture. In a Japanese clinical trial, ingestion of lactoferrin reduced the incidence of infectious gastroenteritis in the participants. Because human noroviruses were the most common cause of gastroenteritis in Japan during the clinical trial period, we sought to determine whether lactoferrin could inhibit infection with human norovirus. Our study, using a B cell culture model, demonstrates that lactoferrin reduces human norovirus infection. The mechanism of antiviral action is likely indirect and may involve the induction of innate interferon responses. Therefore, future studies are warranted to test the antiviral efficacy of lactoferrin against human norovirus infection in patients.
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http://dx.doi.org/10.1139/bcb-2020-0035DOI Listing
February 2021

CD300lf is the primary physiologic receptor of murine norovirus but not human norovirus.

PLoS Pathog 2020 04 6;16(4):e1008242. Epub 2020 Apr 6.

Departments of Laboratory Medicine and Immunobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America.

Murine norovirus (MNoV) is an important model of human norovirus (HNoV) and mucosal virus infection more broadly. Viral receptor utilization is a major determinant of cell tropism, host range, and pathogenesis. The bona fide receptor for HNoV is unknown. Recently, we identified CD300lf as a proteinaceous receptor for MNoV. Interestingly, its paralogue CD300ld was also sufficient for MNoV infection in vitro. Here we explored whether CD300lf is the sole physiologic receptor in vivo and whether HNoV can use a CD300 ortholog as an entry receptor. We report that both CD300ld and CD300lf are sufficient for infection by diverse MNoV strains in vitro. We further demonstrate that CD300lf is essential for both oral and parenteral MNoV infection and to elicit anti-MNoV humoral responses in vivo. In mice deficient in STAT1 signaling, CD300lf is required for MNoV-induced lethality. Finally, we demonstrate that human CD300lf (huCD300lf) is not essential for HNoV infection, nor does huCD300lf inhibit binding of HNoV virus-like particles to glycans. Thus, we report huCD300lf is not a receptor for HNoV.
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http://dx.doi.org/10.1371/journal.ppat.1008242DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7162533PMC
April 2020

Epidemiological and Microbiome Associations Between and Vancomycin-Resistant Colonization in Intensive Care Unit Patients.

Open Forum Infect Dis 2020 Jan 12;7(1):ofaa012. Epub 2020 Jan 12.

Department of Pathology, University of Michigan, Ann Arbor, Michigan, USA.

Background: Prior colonization by and vancomycin-resistant (VRE) is associated with subsequent infection, particularly in intensive care unit (ICU) populations. Screening for VRE colonization, but not , is routinely performed in some health care systems. Identification of patient factors associated with colonization could enable infection prevention.

Methods: ICU patients were screened for VRE and by rectal swab culture over 2 time periods: July-October 2014 (n = 1209) and January-May 2016 (n = 1243). Patient demographics, baseline laboratory data, comorbidities, and outcomes were analyzed. 16S rRNA gene-based analysis was performed on a subset of patients (n = 248) to identify microbiota characteristics associated with VRE and colonization.

Results: colonization (17.3% of patients in the 2014 cohort, 7.3% in 2016) was significantly associated with VRE colonization in multivariable analysis ( = .03 in 2016;  = .08 in 2014). VRE colonization was associated with poor underlying health, whereas colonization was associated with advanced age. The most prevalent operational taxonomic units were spp., and , consistent with high rates of detectable and VRE by culture. Microbial community structure in noncolonized patients was significantly different from those with VRE, or both, attributable to differences in the relative abundance of and .

Conclusions: co-colonizes with VRE and is a predominant taxon in ICU patients, but colonization was not associated with significant comorbidities. Screening for and VRE simultaneously could be an efficient approach for novel infection prevention strategies.
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http://dx.doi.org/10.1093/ofid/ofaa012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6984673PMC
January 2020

Gastrointestinal organoid technology advances studies of enteric virus biology.

PLoS Pathog 2020 01 30;16(1):e1008212. Epub 2020 Jan 30.

Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, United States of America.

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http://dx.doi.org/10.1371/journal.ppat.1008212DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6991956PMC
January 2020

UV Disinfection of Human Norovirus: Evaluating Infectivity Using a Genome-Wide PCR-Based Approach.

Environ Sci Technol 2020 03 10;54(5):2851-2858. Epub 2020 Feb 10.

Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor 48109, Michigan, United States.

The removal and inactivation of infectious human norovirus (HuNoV) is a major focus in water purification, but the effectiveness of disinfection processes on norovirus is largely unknown owing to the lack of a readily available infectivity assay. In particular, norovirus behavior through unit processes may be over- or underestimated using current approaches for assessing HuNoV infectivity (e.g., surrogates, molecular methods). Here, we fill a critical knowledge gap by estimating inactivation data for HuNoV after exposure to UV, a commonly used disinfection process in the water industry. Specifically, we used a PCR-based approach that accurately tracks positive-sense single-stranded RNA virus inactivation without relying on culturing methods. We first confirmed that the approach is valid with a culturable positive-sense single-stranded RNA human virus, coxsackievirus B5, by applying both qPCR- and culture-based methods to measure inactivation kinetics with UV treatment. We then applied the qPCR-based method to establish a UV inactivation curve for HuNoV (inactivation rate constant = 0.27 cm mJ). Based on a comparison with previously published data, HuNoV exhibited similar UV susceptibility compared with other enteric single-stranded RNA viruses (e.g., Echovirus 12, feline calicivirus) but degraded much faster than MS2 (inactivation rate constant = 0.14 cm mJ). In addition to establishing a HuNoV inactivation rate constant, we developed an approach using a single qPCR assay that can be applied to estimate HuNoV inactivation in UV disinfection systems.
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http://dx.doi.org/10.1021/acs.est.9b05747DOI Listing
March 2020

Inactivation of Murine Norovirus and Fecal Coliforms by Ferrate(VI) in Secondary Effluent Wastewater.

Environ Sci Technol 2020 02 13;54(3):1878-1888. Epub 2020 Jan 13.

Department of Chemical and Biochemical Engineering , University of Western Ontario , London , Ontario N6A5B9 , Canada.

Ferrate(VI) (FeO, Fe(VI)) is an emerging oxidant/disinfectant to treat a wide range of contaminants and microbial pollutants in wastewater. This study describes the inactivation of murine norovirus (MNV) by Fe(VI) in phosphate buffer (PB) and secondary effluent wastewater (SEW). The decay of Fe(VI) had second-order kinetics in PB while Fe(VI) underwent an initial demand followed by first-order decay kinetics in SEW. The Chick-Watson inactivation kinetic model, based on integral CT (ICT) dose, well fitted the inactivation of MNV in both PB and SEW. In PB, the values of the inactivation rate constant () decreased with an increase in pH, which was related to the reaction of protonated Fe(VI) species (HFeO) with MNV. Higher was observed in SEW than in PB. The inactivation of indigenous fecal coliforms (FC) in SEW was also measured. A two-population double-exponential model that accounted for both dispersed and particle-associated FC well fitted the inactivation data with determined and particle-associated inactivation rate constant (). Results show that Fe(VI) was more effective in inactivating dispersed FC than MNV. The MNV inactivation results obtained herein, coupled with the detailed modeling, provide important information in designing an Fe(VI) wastewater disinfection process.
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http://dx.doi.org/10.1021/acs.est.9b05489DOI Listing
February 2020

The intestinal regionalization of acute norovirus infection is regulated by the microbiota via bile acid-mediated priming of type III interferon.

Nat Microbiol 2020 01 25;5(1):84-92. Epub 2019 Nov 25.

Department of Molecular Genetics & Microbiology, Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.

Evidence has accumulated to demonstrate that the intestinal microbiota enhances mammalian enteric virus infections. For example, we and others previously reported that commensal bacteria stimulate acute and persistent murine norovirus infections. However, in apparent contradiction of these results, the virulence of murine norovirus infection was unaffected by antibiotic treatment. This prompted us to perform a detailed investigation of murine norovirus infection in microbially deplete mice, revealing a more complex picture in which commensal bacteria inhibit viral infection of the proximal small intestine while simultaneously stimulating the infection of distal regions of the gut. Thus, commensal bacteria can regulate viral regionalization along the intestinal tract. We further show that the mechanism underlying bacteria-dependent inhibition of norovirus infection in the proximal gut involves bile acid priming of type III interferon. Finally, the regional effects of the microbiota on norovirus infection may result from distinct regional expression profiles of key bile acid receptors that regulate the type III interferon response. Overall, these findings reveal that the biotransformation of host metabolites by the intestinal microbiota directly and regionally impacts infection by a pathogenic enteric virus.
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http://dx.doi.org/10.1038/s41564-019-0602-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6925324PMC
January 2020

Astrovirus replication in human intestinal enteroids reveals multi-cellular tropism and an intricate host innate immune landscape.

PLoS Pathog 2019 10 31;15(10):e1008057. Epub 2019 Oct 31.

Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, United States of America.

Human astroviruses (HAstV) are understudied positive-strand RNA viruses that cause gastroenteritis mostly in children and the elderly. Three clades of astroviruses, classic, MLB-type and VA-type have been reported in humans. One limitation towards a better understanding of these viruses has been the lack of a physiologically relevant cell culture model that supports growth of all clades of HAstV. Herein, we demonstrate infection of HAstV strains belonging to all three clades in epithelium-only human intestinal enteroids (HIE) isolated from biopsy-derived intestinal crypts. A detailed investigation of infection of VA1, a member of the non-canonical HAstV-VA/HMO clade, showed robust replication in HIE derived from different patients and from different intestinal regions independent of the cellular differentiation status. Flow cytometry and immunofluorescence analysis revealed that VA1 infects several cell types, including intestinal progenitor cells and mature enterocytes, in HIE cultures. RNA profiling of VA1-infected HIE uncovered that the host response to infection is dominated by interferon (IFN)-mediated innate immune responses. A comparison of the antiviral host response in non-transformed HIE and transformed human colon carcinoma Caco-2 cells highlighted significant differences between these cells, including an increased magnitude of the response in HIE. Additional studies confirmed the sensitivity of VA1 to exogenous IFNs, and indicated that the endogenous IFN response of HIE to curtail the growth of strains from all three clades. Genotypic variation in the permissiveness of different HIE lines to HAstV could be overcome by pharmacologic inhibition of JAK/STAT signaling. Collectively, our data identify HIE as a universal infection model for HAstV and an improved model of the intestinal epithelium to investigate enteric virus-host interactions.
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http://dx.doi.org/10.1371/journal.ppat.1008057DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6957189PMC
October 2019

The inert meets the living: The expanding view of metabolic alterations during viral pathogenesis.

PLoS Pathog 2019 07 25;15(7):e1007830. Epub 2019 Jul 25.

Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, United States of America.

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http://dx.doi.org/10.1371/journal.ppat.1007830DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6657903PMC
July 2019

Editorial overview: Viruses and the microbiome.

Curr Opin Virol 2019 08 20;37:iii-vi. Epub 2019 Jul 20.

Department of Microbiology and Immunology, University of Michigan, United States.

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http://dx.doi.org/10.1016/j.coviro.2019.06.012DOI Listing
August 2019

Perturbation of ubiquitin homeostasis promotes macrophage oxidative defenses.

Sci Rep 2019 07 15;9(1):10245. Epub 2019 Jul 15.

Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, 48109, United States of America.

The innate immune system senses microbial ligands through pattern recognition and triggers downstream signaling cascades to promote inflammation and immune defense mechanisms. Emerging evidence suggests that cells also recognize alterations in host processes induced by infection as triggers. Protein ubiquitination and deubiquitination are post-translational modification processes essential for signaling and maintenance of cellular homeostasis, and infections can cause global alterations in the host ubiquitin proteome. Here we used a chemical biology approach to perturb the cellular ubiquitin proteome as a simplified model to study the impact of ubiquitin homeostasis alteration on macrophage function. Perturbation of ubiquitin homeostasis led to a rapid and transient burst of reactive oxygen species (ROS) that promoted macrophage inflammatory and anti-infective capacity. Moreover, we found that ROS production was dependent on the NOX2 phagocyte NADPH oxidase. Global alteration of the ubiquitin proteome also enhanced proinflammatory cytokine production in mice stimulated with a sub-lethal dose of LPS. Collectively, our findings suggest that major changes in the host ubiquitin landscape may be a potent signal to rapidly deploy innate immune defenses.
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http://dx.doi.org/10.1038/s41598-019-46526-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6629656PMC
July 2019

Glycolysis Is an Intrinsic Factor for Optimal Replication of a Norovirus.

mBio 2019 03 12;10(2). Epub 2019 Mar 12.

Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA

The metabolic pathways of central carbon metabolism, glycolysis and oxidative phosphorylation (OXPHOS), are important host factors that determine the outcome of viral infections and can be manipulated by some viruses to favor infection. However, mechanisms of metabolic modulation and their effects on viral replication vary widely. Herein, we present the first metabolomics and energetic profiling of norovirus-infected cells, which revealed increases in glycolysis, OXPHOS, and the pentose phosphate pathway (PPP) during murine norovirus (MNV) infection. Inhibiting glycolysis with 2-deoxyglucose (2DG) in macrophages revealed that glycolysis is an important factor for optimal MNV infection, while inhibiting the PPP and OXPHOS showed a relatively minor impact of these pathways on MNV infection. 2DG affected an early stage in the viral life cycle after viral uptake and capsid uncoating, leading to decreased viral protein production and viral RNA. The requirement of glycolysis was specific for MNV (but not astrovirus) infection, independent of the type I interferon antiviral response, and unlikely to be due to a lack of host cell nucleotide synthesis. MNV infection increased activation of the protein kinase Akt, but not AMP-activated protein kinase (AMPK), two master regulators of cellular metabolism, implicating Akt signaling in upregulating host metabolism during norovirus infection. In conclusion, our findings suggest that the metabolic state of target cells is an intrinsic host factor that determines the extent of norovirus replication and implicates glycolysis as a virulence determinant. They further point to cellular metabolism as a novel therapeutic target for norovirus infections and improvements in current human norovirus culture systems. Viruses depend on the host cells they infect to provide the machinery and substrates for replication. Host cells are highly dynamic systems that can alter their intracellular environment and metabolic behavior, which may be helpful or inhibitory for an infecting virus. In this study, we show that macrophages, a target cell of murine norovirus (MNV), increase glycolysis upon viral infection, which is important for early steps in MNV infection. Human noroviruses (hNoV) are a major cause of gastroenteritis globally, causing enormous morbidity and economic burden. Currently, no effective antivirals or vaccines exist for hNoV, mainly due to the lack of high-efficiency culture models for their study. Thus, insights gained from the MNV model may reveal aspects of host cell metabolism that can be targeted for improving hNoV cell culture systems and for developing effective antiviral therapies.
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http://dx.doi.org/10.1128/mBio.02175-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414699PMC
March 2019

Intestinal non-canonical NFκB signaling shapes the local and systemic immune response.

Nat Commun 2019 02 8;10(1):660. Epub 2019 Feb 8.

Department of Molecular & Integrative Physiology, University of Michigan, Michigan, MI, 48109, USA.

Microfold cells (M-cells) are specialized cells of the intestine that sample luminal microbiota and dietary antigens to educate the immune cells of the intestinal lymphoid follicles. The function of M-cells in systemic inflammatory responses are still unclear. Here we show that epithelial non-canonical NFkB signaling mediated by NFkB-inducing kinase (NIK) is highly active in intestinal lymphoid follicles, and is required for M-cell maintenance. Intestinal NIK signaling modulates M-cell differentiation and elicits both local and systemic IL-17A and IgA production. Importantly, intestinal NIK signaling is active in mouse models of colitis and patients with inflammatory bowel diseases; meanwhile, constitutive NIK signaling increases the susceptibility to inflammatory injury by inducing ectopic M-cell differentiation and a chronic increase of IL-17A. Our work thus defines an important function of non-canonical NFkB and M-cells in immune homeostasis, inflammation and polymicrobial sepsis.
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http://dx.doi.org/10.1038/s41467-019-08581-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6368617PMC
February 2019