Innate immunity gene expression by epithelial cells of upper respiratory tract in children with adenoid hypertrophy

AbstractKey elements for viral pathogenesis include viral strains, viral load, co-infection, and host responses. Several studies analyzing these factors in the function of disease severity of have been published; however, no studies have shown how all of these factors interplay within a defined cohort. To address this important question, we sought to understand how these four key components interplay in a cohort of COVID-19 patients. We determined the viral loads and gene expression using high throughput sequencing and various virological methods. We found that viral loads in the upper respiratory tract in COVID-19 patients at an early phase of infection vary widely. While the majority of nasopharyngeal (NP) samples have a viral load lower than the limit of detection of infectious viruses, there are samples with an extraordinary amount of SARS-CoV-2 RNA and a high viral titer. No specific viral factors were identified that are associated with high viral loads. Host gene expression analysis showed that viral loads were strongly correlated with cellular antiviral responses. Interestingly, however, COVID-19 patients who experience mild symptoms have a higher viral load than those with severe complications, indicating that naso-pharyngeal viral load may not be a key factor of the clinical outcomes of COVID-19. The metagenomics analysis revealed that the microflora in the upper respiratory tract of COVID-19 patients with high viral loads were dominated by SARS-CoV-2, with a high degree of dysbiosis. Finally, we found a strong inverse correlation between upregulation of interferon responses and disease severity. Overall our study suggests that a high viral load in the upper respiratory tract may not be a critical factor for severe symptoms; rather, dampened antiviral responses may be a critical factor for a severe outcome from the infection.

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Innate Immune Responses to Influenza Virus Infections in the Upper Respiratory Tract

Viruses ◽

10.3390/v13102090 ◽

2021 ◽

Vol 13 (10) ◽

pp. 2090

Author(s):

Edin J. Mifsud ◽

Miku Kuba ◽

Ian G. Barr

Keyword(s):

Influenza Virus ◽

Immune System ◽

Epithelial Cells ◽

Immune Responses ◽

Respiratory Tract ◽

Innate Immune System ◽

Innate Immune ◽

Upper Respiratory Tract ◽

Adaptive Immune ◽

Upper Respiratory

The innate immune system is the host’s first line of immune defence against any invading pathogen. To establish an infection in a human host the influenza virus must replicate in epithelial cells of the upper respiratory tract. However, there are several innate immune mechanisms in place to stop the virus from reaching epithelial cells. In addition to limiting viral replication and dissemination, the innate immune system also activates the adaptive immune system leading to viral clearance, enabling the respiratory system to return to normal homeostasis. However, an overzealous innate immune system or adaptive immune response can be associated with immunopathology and aid secondary bacterial infections of the lower respiratory tract leading to pneumonia. In this review, we discuss the mechanisms utilised by the innate immune system to limit influenza virus replication and the damage caused by influenza viruses on the respiratory tissues and how these very same protective immune responses can cause immunopathology.

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The histone demethylase KDM6B fine-tunes the host response to Streptococcus pneumoniae

10.1101/757906 ◽

2019 ◽

Author(s):

Michael G. Connor ◽

Tiphaine Marie-Noelle Camarasa ◽

Emma Patey ◽

Orhan Rasid ◽

Laura Barrio ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Epithelial Cells ◽

Respiratory Tract ◽

Chromatin Remodeling ◽

Host Response ◽

Histone Demethylase ◽

Infection Model ◽

Dependent Manner ◽

Upper Respiratory Tract ◽

Upper Respiratory

AbstractStreptococcus pneumoniae is a natural colonizer of the human upper respiratory tract and an opportunistic pathogen. After colonization, bacteria either remain in the human upper respiratory tract, or may progress to cause pneumococcal disease. Although epithelial cells are among the first to encounter pneumococci, the cellular processes and contribution of epithelial cells to the host response are poorly understood. Here, we show a S. pneumoniae serotype 6B ST90 strain, which does not cause disease in a murine infection model, induces a unique NF-κB signature response distinct from an invasive disease causing isolate of serotype 4 (TIGR4). This signature is characterized by activation of p65 (RelA) and requires a histone demethylase, KDM6B. At the molecular level, we show that interaction of the 6B strain with epithelial cells leads to chromatin remodeling within the IL-11 promoter in a KDM6B dependent manner, where KDM6B specifically demethylates histone H3 lysine 27 di-methyl. Chromatin remodeling of the IL-11 locus facilitates p65 access to three NF-κB sites, which are otherwise inaccessible when stimulated by IL-1β or TIGR4. Finally, we demonstrate through chemical inhibition of KDM6B, with GSK-J4 inhibitor, and through exogenous addition of IL-11 that the host responses to 6B ST90 and TIGR4 strains can be interchanged both in vitro and in a murine model of infection in vivo. Our studies hereby reveal how a chromatin modifier governs cellular responses during infection.

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Infection of lymphoid tissues in the macaque upper respiratory tract contributes to the emergence of transmissible measles virus

Journal of General Virology ◽

10.1099/vir.0.054650-0 ◽

2013 ◽

Vol 94 (9) ◽

pp. 1933-1944 ◽

Cited By ~ 25

Author(s):

Martin Ludlow ◽

Rory D. de Vries ◽

Ken Lemon ◽

Stephen McQuaid ◽

Emma Millar ◽

...

Keyword(s):

Epithelial Cells ◽

Respiratory Tract ◽

Immune Cells ◽

Measles Virus ◽

Upper Respiratory Tract ◽

Free Virus ◽

Cell Debris ◽

Cell Layers ◽

Infected Cells ◽

Upper Respiratory

Measles virus (MV), a member of the family Paramyxoviridae, remains a major cause of morbidity and mortality in the developing world. MV is spread by aerosols but the mechanism(s) responsible for the high transmissibility of MV are largely unknown. We previously infected macaques with enhanced green fluorescent protein-expressing recombinant MV and euthanized them at a range of time points. In this study a comprehensive pathological analysis has been performed of tissues from the respiratory tract around the peak of virus replication. Isolation of virus from nose and throat swab samples showed that high levels of both cell-associated and cell-free virus were present in the upper respiratory tract. Analysis of tissue sections from lung and primary bronchus revealed localized infection of epithelial cells, concomitant infiltration of MV-infected immune cells into the epithelium and localized shedding of cells or cell debris into the lumen. While high numbers of MV-infected cells were present in the tongue, these were largely encapsulated by intact keratinocyte cell layers that likely limit virus transmission. In contrast, the integrity of tonsillar and adenoidal epithelia was disrupted with high numbers of MV-infected epithelial cells and infiltrating immune cells present throughout epithelial cell layers. Disruption was associated with large numbers of MV-infected cells or cell debris ‘spilling’ from epithelia into the respiratory tract. The coughing and sneezing response induced by disruption of the ciliated epithelium, leading to the expulsion of MV-infected cells, cell debris and cell-free virus, contributes to the highly infectious nature of MV.

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Cigarette smoke suppresses innate immunity of the upper-respiratory tract leading to enhanced colonization of the lung

Pneumologie ◽

10.1055/s-0032-1329809 ◽

2012 ◽

Vol 66 (11) ◽

Author(s):

M Voss ◽

M Bischoff ◽

C Herr ◽

R Bals ◽

C Beisswenger

Keyword(s):

Innate Immunity ◽

Respiratory Tract ◽

Cigarette Smoke ◽

Upper Respiratory Tract ◽

Upper Respiratory

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Cigarette smoke suppresses innate immunity of the upper-respiratory tract leading to enhanced colonization of the lung

Pneumologie ◽

10.1055/s-0033-1334527 ◽

2013 ◽

Vol 67 (S 01) ◽

Author(s):

M Voss ◽

J Hellberg ◽

M Bischoff ◽

C Herr ◽

R Bals ◽

...

Keyword(s):

Innate Immunity ◽

Respiratory Tract ◽

Cigarette Smoke ◽

Upper Respiratory Tract ◽

Upper Respiratory

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Dual and Triple Epithelial Coculture Model Systems with Donor-Derived Microbiota and THP-1 Macrophages To Mimic Host-Microbe Interactions in the Human Sinonasal Cavities

mSphere ◽

10.1128/msphere.00916-19 ◽

2020 ◽

Vol 5 (1) ◽

Cited By ~ 1

Author(s):

Charlotte De Rudder ◽

Marta Calatayud Arroyo ◽

Sarah Lebeer ◽

Tom Van de Wiele

Keyword(s):

Microbial Community ◽

Epithelial Cells ◽

Respiratory Tract ◽

Model Systems ◽

Upper Respiratory Tract ◽

Microbe Interactions ◽

Upper Respiratory ◽

Host Microbe Interactions ◽

Nasal Microbiota

ABSTRACT The epithelium of the human sinonasal cavities is colonized by a diverse microbial community, modulating epithelial development and immune priming and playing a role in respiratory disease. Here, we present a novel in vitro approach enabling a 3-day coculture of differentiated Calu-3 respiratory epithelial cells with a donor-derived bacterial community, a commensal species (Lactobacillus sakei), or a pathobiont (Staphylococcus aureus). We also assessed how the incorporation of macrophage-like cells could have a steering effect on both epithelial cells and the microbial community. Inoculation of donor-derived microbiota in our experimental setup did not pose cytotoxic stress on the epithelial cell layers, as demonstrated by unaltered cytokine and lactate dehydrogenase release compared to a sterile control. Epithelial integrity of the differentiated Calu-3 cells was maintained as well, with no differences in transepithelial electrical resistance observed between coculture with donor-derived microbiota and a sterile control. Transition of nasal microbiota from in vivo to in vitro conditions maintained phylogenetic richness, and yet a decrease in phylogenetic and phenotypic diversity was noted. Additional inclusion and coculture of THP-1-derived macrophages did not alter phylogenetic diversity, and yet donor-independent shifts toward higher Moraxella and Mycoplasma abundance were observed, while phenotypic diversity was also increased. Our results demonstrate that coculture of differentiated airway epithelial cells with a healthy donor-derived nasal community is a viable strategy to mimic host-microbe interactions in the human upper respiratory tract. Importantly, including an immune component allowed us to study host-microbe interactions in the upper respiratory tract more in depth. IMPORTANCE Despite the relevance of the resident microbiota in sinonasal health and disease and the need for cross talk between immune and epithelial cells in the upper respiratory tract, these parameters have not been combined in a single in vitro model system. We have developed a coculture system of differentiated respiratory epithelium and natural nasal microbiota and incorporated an immune component. As indicated by absence of cytotoxicity and stable cytokine profiles and epithelial integrity, nasal microbiota from human origin appeared to be well tolerated by host cells, while microbial community composition remained representative for that of the human (sino)nasal cavity. Importantly, the introduction of macrophage-like cells enabled us to obtain a differential readout from the epithelial cells dependent on the donor microbial background to which the cells were exposed. We conclude that both model systems offer the means to investigate host-microbe interactions in the upper respiratory tract in a more representative way.

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