Influence of glycan structure on the colonization of Streptococcus pneumoniae on human respiratory epithelial cells.

Virtually all living cells are encased in glycans. They perform key cellular functions such as immunomodulation and cell-cell recognition. Yet, how their composition and configuration affect their functions remains enigmatic. Here, we constructed isogenic capsule-switch mutants harboring 84 types of capsular polysaccharides (CPSs) in Streptococcus pneumoniae. This collection enables us to systematically measure the affinity of structurally related CPSs to primary human nasal and bronchial epithelial cells. Contrary to the paradigm, the surface charge does not appreciably affect epithelial cell binding. Factors that affect adhesion to respiratory cells include the number of rhamnose residues and the presence of human-like glycomotifs in CPS. Besides, pneumococcal colonization stimulated the production of interleukin 6 (IL-6), granulocyte-macrophage colony-stimulating factor (GM-CSF), and monocyte chemoattractantprotein-1 (MCP-1) in nasal epithelial cells, which also appears to be dependent on the serotype. Together, our results reveal glycomotifs of surface polysaccharides that are likely to be important for colonization and survival in the human airway.

Single-shot dendritic cell targeting SARS-CoV-2 vaccine candidate induces broad, durable and protective systemic and mucosal immunity in mice.

Current coronavirus disease 2019 vaccines face limitations including waning immunity, immune escape by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, limited cellular response, and poor mucosal immunity. We engineered a Clec9A-receptor binding domain (RBD) antibody construct that delivers the SARS-CoV-2 RBD to conventional type 1 dendritic cells. Compared with non-targeting approaches, single dose immunization in mice with Clec9A-RBD induced far higher RBD-specific antibody titers that were sustained for up to 21 months after vaccination. Uniquely, increasing neutralizing and antibody-dependent cytotoxicity activities across the sarbecovirus family was observed, suggesting antibody affinity maturation over time. Consistently and remarkably, RBD-specific follicular T helper cells and germinal center B cells persisted up to 12 months after immunization. Furthermore, Clec9A-RBD immunization induced a durable mono- and poly-functional T-helper 1-biased cellular response that was strongly cross-reactive against SARS-CoV-2 variants of concern, including Omicron subvariants, and with a robust CD8+ T cell signature. Uniquely, Clec9A-RBD single-shot systemic immunization effectively primed RBD-specific cellular and humoral immunity in lung and resulted in significant protection against homologous SARS-CoV-2 challenge as evidenced by limited body weight loss and approximately 2 log10 decrease in lung viral loads compared with non-immunized controls. Therefore, Clec9A-RBD immunization has the potential to trigger robust and sustained, systemic and mucosal protective immunity against rapidly evolving SARS-CoV2 variants.

Hypoxia-inducible factor 1α activates the NLRP3 inflammasome to regulate epithelial differentiation in chronic rhinosinusitis.

BACKGROUND: Chronic rhinosinusitis (CRS) is an upper airway inflammation disease associated with hypoxia-mediated inflammation. The effect of hypoxia-inducible factor 1α (HIF-1α) on NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation in the pathogenesis of sinonasal mucosa is unclear. OBJECTIVE: We investigated the effect and mechanism of HIF-1α on NLRP3 inflammasome activation in the primary human nasal epithelial cells (hNECs). METHODS: We measured the expression levels of HIF-1α and the NLRP3 inflammasome in nasal biopsy samples and hNECs derived from negative controls (healthy) and patients with CRS with and without nasal polyps, then further analyzed the specific mechanism of HIF-1α regulation of the NLRP3 inflammasome and its effect on hNEC differentiation. RESULTS: Increased mRNA and protein expression levels of HIF-1α and the NLRP3 inflammasome were found in all CRS biopsy samples. HIF-1α enhanced expression of phosphorylated NLRP3 (S295) in both HEK293T cells and hNECs; it also promoted recruitment of caspase-1 and apoptotic speck-like protein containing caspase recruitment domain (aka ASC) by NLRP3. HIF-1α also improved NLRP3's stability by preventing NLRP3 degradation caused by hypoxia-mediated inflammation. In addition, HIF-1α could also increase expression of Mucin5AC and decrease expression of α-tubulin by promoting activation of the NLRP3 inflammasome in hNECs. In addition, HIF-1α could also directly promote P63 expression in hNECs. CONCLUSION: HIF-1α could potentially induce cilia loss and enhance the proliferation of goblet cells, possibly mediated by the regulation of NLRP3 phosphorylation in CRS inflammation.

Differential effects of microRNAs miR-21, miR-99 and miR-145 on lung regeneration and inflammation during recovery from influenza pneumonia.

In a mouse model of influenza pneumonia, we previously documented that proliferating alveolar type II (AT2) cells are the major stem cells involved in early lung recovery. Profiling of microRNAs revealed significant dysregulation of specific ones, including miR-21 and miR-99a. Moreover, miR-145 is known to exhibit antagonism to miR-21. This follow-up study investigated the roles of microRNAs miR-21, miR-99a, and miR-145 in the murine pulmonary regenerative process and inflammation during influenza pneumonia. Inhibition of miR-21 resulted in severe morbidity, and in significantly decreased proliferating AT2 cells due to impaired transition from innate to adaptive immune responses. Knockdown of miR-99a culminated in moderate morbidity, with a significant increase in proliferating AT2 cells that may be linked to PTEN downregulation. In contrast, miR-145 antagonism did not impact morbidity nor the proliferating AT2 cell population, and was associated with downregulation of TNF-alpha, IL1-beta, YM1, and LY6G. Hence, a complex interplay exists between expression of specific miRNAs, lung regeneration, and inflammation during recovery from influenza pneumonia. Inhibition of miR-21 and miR-99a (but not miR-145) can lead to deleterious cellular and molecular effects on pulmonary repair and inflammatory processes during influenza pneumonia.

Viral Load of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Respiratory Aerosols Emitted by Patients With Coronavirus Disease 2019 (COVID-19) While Breathing, Talking, and Singing.

BACKGROUND: Multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) superspreading events suggest that aerosols play an important role in driving the coronavirus disease 2019 (COVID-19) pandemic. To better understand how airborne SARS-CoV-2 transmission occurs, we sought to determine viral loads within coarse (>5 µm) and fine (≤5 µm) respiratory aerosols produced when breathing, talking, and singing. METHODS: Using a G-II exhaled breath collector, we measured viral RNA in coarse and fine respiratory aerosols emitted by COVID-19 patients during 30 minutes of breathing, 15 minutes of talking, and 15 minutes of singing. RESULTS: Thirteen participants (59%) emitted detectable levels of SARS-CoV-2 RNA in respiratory aerosols, including 3 asymptomatic and 1 presymptomatic patient. Viral loads ranged from 63-5821 N gene copies per expiratory activity per participant, with high person-to-person variation. Patients earlier in illness were more likely to emit detectable RNA. Two participants, sampled on day 3 of illness, accounted for 52% of total viral load. Overall, 94% of SARS-CoV-2 RNA copies were emitted by talking and singing. Interestingly, 7 participants emitted more virus from talking than singing. Overall, fine aerosols constituted 85% of the viral load detected in our study. Virus cultures were negative. CONCLUSIONS: Fine aerosols produced by talking and singing contain more SARS-CoV-2 copies than coarse aerosols and may play a significant role in SARS-CoV-2 transmission. Exposure to fine aerosols, especially indoors, should be mitigated. Isolating viable SARS-CoV-2 from respiratory aerosol samples remains challenging; whether this can be more easily accomplished for emerging SARS-CoV-2 variants is an urgent enquiry necessitating larger-scale studies.

Infection of human Nasal Epithelial Cells with SARS-CoV-2 and a 382-nt deletion isolate lacking ORF8 reveals similar viral kinetics and host transcriptional profiles.

The novel coronavirus SARS-CoV-2 is the causative agent of Coronavirus Disease 2019 (COVID-19), a global healthcare and economic catastrophe. Understanding of the host immune response to SARS-CoV-2 is still in its infancy. A 382-nt deletion strain lacking ORF8 (Δ382 herein) was isolated in Singapore in March 2020. Infection with Δ382 was associated with less severe disease in patients, compared to infection with wild-type SARS-CoV-2. Here, we established Nasal Epithelial cells (NECs) differentiated from healthy nasal-tissue derived stem cells as a suitable model for the ex-vivo study of SARS-CoV-2 mediated pathogenesis. Infection of NECs with either SARS-CoV-2 or Δ382 resulted in virus particles released exclusively from the apical side, with similar replication kinetics. Screening of a panel of 49 cytokines for basolateral secretion from infected NECs identified CXCL10 as the only cytokine significantly induced upon infection, at comparable levels in both wild-type and Δ382 infected cells. Transcriptome analysis revealed the temporal up-regulation of distinct gene subsets during infection, with anti-viral signaling pathways only detected at late time-points (72 hours post-infection, hpi). This immune response to SARS-CoV-2 was significantly attenuated when compared to infection with an influenza strain, H3N2, which elicited an inflammatory response within 8 hpi, and a greater magnitude of anti-viral gene up-regulation at late time-points. Remarkably, Δ382 induced a host transcriptional response nearly identical to that of wild-type SARS-CoV-2 at every post-infection time-point examined. In accordance with previous results, Δ382 infected cells showed an absence of transcripts mapping to ORF8, and conserved expression of other SARS-CoV-2 genes. Our findings shed light on the airway epithelial response to SARS-CoV-2 infection, and demonstrate a non-essential role for ORF8 in modulating host gene expression and cytokine production from infected cells.

Transcriptomics of rhinovirus persistence reveals sustained expression of RIG-I and interferon-stimulated genes in nasal epithelial cells in vitro.

BACKGROUND: Human rhinoviruses (HRVs) are frequently associated with asthma exacerbations, and have been found in the airways of asthmatic patients. While HRV-induced acute infection is well-documented, it is less clear whether the nasal epithelium sustains prolonged HRV infections along with the associated activation of host immune responses. OBJECTIVE: To investigate sustainably regulated host responses of human nasal epithelial cells (hNECs) during HRV persistence. METHODS: Using a time-course study, HRV16 persistence and viral replication dynamics were established using an in vitro infection model of hNECs. RNA sequencing was performed on hNECs in the early and late stages of infection at 3 and 14 days post-infection (dpi), respectively. The functional enrichment of differentially expressed genes (DEGs) was evaluated using gene ontology (GO) and Ingenuity pathway analysis. RESULTS: HRV RNA and protein expression persisted throughout prolonged infections, even after decreased production of infectious virus progeny. GO analysis of unique DEGs indicated altered regulation of pathways related to ciliary function and airway remodeling at 3 dpi and serine-type endopeptidase activity at 14 dpi. The functional enrichment of shared DEGs between the two time-points was related to interferon (IFN) and cytoplasmic pattern recognition receptor (PRR) signaling pathways. Validation of the sustained regulation of candidate genes confirmed the persistent expression of RIG-I and revealed its close co-regulation with interferon-stimulated genes (ISGs) during HRV persistence. CONCLUSIONS: The persistence of HRV RNA does not necessarily indicate an active infection during prolonged infection. The sustained expression of RIG-I and ISGs in response to viral RNA persistence highlights the importance of assessing how immune-activating host factors can change during active HRV infection and the immune regulation that persists thereafter.

Tetraspanins: Host Factors in Viral Infections.

Tetraspanins are transmembrane glycoproteins that have been shown increasing interest as host factors in infectious diseases. In particular, they were implicated in the pathogenesis of both non-enveloped (human papillomavirus (HPV)) and enveloped (human immunodeficiency virus (HIV), Zika, influenza A virus, (IAV), and coronavirus) viruses through multiple stages of infection, from the initial cell membrane attachment to the syncytium formation and viral particle release. However, the mechanisms by which different tetraspanins mediate their effects vary. This review aimed to compare and contrast the role of tetraspanins in the life cycles of HPV, HIV, Zika, IAV, and coronavirus viruses, which cause the most significant health and economic burdens to society. In doing so, a better understanding of the relative contribution of tetraspanins in virus infection will allow for a more targeted approach in the treatment of these diseases.

Whole-transcriptome sequencing reveals heightened inflammation and defective host defence responses in chronic rhinosinusitis with nasal polyps.

INTRODUCTION: The pathways underlying chronic rhinosinusitis with nasal polyps (CRSwNP) are unclear. We conducted genome-wide gene expression analysis to determine pathways and candidate gene sets associated with CRSwNP. METHODS: We performed whole-transcriptome RNA sequencing on 42 polyp (CRSwNP-NP) and 33 paired nonpolyp inferior turbinate (CRSwNP-IT) tissues from patients with CRSwNP and 28 inferior turbinate samples from non-CRS controls (CS-IT). We analysed the differentially expressed genes (DEGs) and the gene sets that were enriched in functional pathways. RESULTS: Principal component-informed analysis revealed cilium function and immune regulation as the two main Gene Ontology (GO) categories differentiating CRSwNP patients from controls. We detected 6182 and 1592 DEGs between CRSwNP-NP versus CS-IT and between CRSwNP-NP versus CRSwNP-IT tissues, respectively. Atopy status did not have a major impact on gene expression in various tissues. GO analysis on these DEGs implicated extracellular matrix (ECM) disassembly, O-glycan processing, angiogenesis and host viral response in CRSwNP pathogenesis. Ingenuity Pathway Analysis identified significant enrichment of type 1 interferon signalling and axonal guidance canonical pathways, angiogenesis, and collagen and fibrotic changes in CRSwNP (CRSwNP-NP and CRSwNP-IT) tissues compared with CS-IT. Finally, gene set enrichment analysis implicated sets of genes co-regulated in processes associated with inflammatory response and aberrant cell differentiation in polyp formation. CONCLUSIONS: Gene signatures involved in defective host defences (including cilia dysfunction and immune dysregulation), inflammation and abnormal metabolism of ECM are implicated in CRSwNP. Functional validation of these gene expression patterns will open opportunities for CRSwNP therapeutic interventions such as biologics and immunomodulators.

Distribution and Determinants of Dermatophagoides Mites Sensitization ofAllergic Rhinitis and Allergic Asthma in China.

BACKGROUND: The implementation of allergen immunotherapy (AIT) requires extensive knowledge of allergen distribution in the region to identify high-risk regions for AIT utilization. However, the geographical distribution patterns of the major Dermatophagoides allergens in China remain unclear despite the increasing prevalence of these allergens. METHODS: We performed comprehensive database searches of articles demonstrating the distribution patterns of Dermatophagoides-sensitized allergic rhinitis (AR) and allergic asthma (AA) in China, published between 1990 and 2017. RESULTS: We retrieved 163 articles encompassing 114,302 allergen-positive cases to generate the distribution maps. The rate of sensitization to Dermatophagoides pteronyssinus(D. pteronyssinus)and Dermatophagoides farinae (D. farinae) was similar in patients with AR (75.1 vs. 75.2%, p > 0.05) but not in those with AA (78.5 vs. 77.7%, p = 0.041). Patients with AR and AA shared similar regional distribution patterns of both D. pteronyssinus and D. farinae sensitization, which were highest in the southern and central parts of China and lowest in the northern regions, especially in the Northwest. The overall rate of sensitization to D. pteronyssinus and D. farinae was significantly higher in patients with AA (p < 0.001). Additionally, the annual mean temperature and humidity were the 2 major determinants of D. pteronyssinus and D. farinae sensitization in AR and of D. pteronyssinus sensitization in AA, whereas the annual mean temperature was the sole determinant for D. farinae sensitization in AA. CONCLUSION: These findings may inform clinicians of the strategies for the prevention of Dermatophagoides sensitization and may be of benefit to the future clinical management of allergic diseasesassociated with sensitization to Dermatophagoides mites.

Upregulation of cell-surface mucin MUC15 in human nasal epithelial cells upon influenza A virus infection.

BACKGROUND: Cell-surface mucins are expressed in apical epithelial cells of the respiratory tract, and contribute a crucial part of the innate immune system. Despite anti-inflammatory or antiviral functions being revealed for certain cell-surface mucins such as MUC1, the roles of other mucins are still poorly understood, especially in viral infections. METHODS: To further identify mucins significant in influenza infection, we screened the expression of mucins in human nasal epithelial cells infected by H3N2 influenza A virus. RESULTS: We found that the expression of MUC15 was significantly upregulated upon infection, and specific only to active infection. While MUC15 did not interact with virus particles or reduce viral replication directly, positive correlations were observed between MUC15 and inflammatory factors in response to viral infection. Given that the upregulation of MUC15 was only triggered late into infection when immune factors (including cytokines, chemokines, EGFR and phosphorylated ERK) started to peak and plateau, MUC15 may potentially serve an immunomodulatory function later during influenza viral infection. CONCLUSIONS: Our study revealed that MUC15 was one of the few cell-surface mucins induced during influenza infection. While MUC15 did not interact directly with influenza virus, we showed that its increase coincides with the peak of immune activation and thus MUC15 may serve an immunomodulatory role during influenza infection.

H3N2 influenza virus infection enhances oncostatin M expression in human nasal epithelium.

Tight junctions (TJs) alteration is commonly seen in airway inflammatory diseases. Oncostatin M (OSM) is an inflammatory mediator associated with chronic rhinosinusitis with nasal polyps (CRSwNP). We have previously shown that human nasal epithelial cells (hNECs) are highly permissive cells for influenza A virus (IAV). However, its role in TJs alteration and the effects of IAV on inducing OSM expression in nasal epithelium remains to be further investigated. In this study, OSM and TJs expression was measured and compared between inferior turbinate from healthy controls and nasal polyps from CRSwNP. Additionally, hNECs cultured at air-liquid interface (ALI) were infected with H3N2 influenza virus to study the role of influenza virus in inducing epithelial OSM expression as a possible means of exacerbation. The expression of ZO-1, claudin-1, and occludin was markedly decreased and correlated negatively with that of OSM in CRSwNP. By using the in vitro hNEC model, H3N2 infection resulted in significantly increased OSM expression (2.2-, 4.7- and 3.9-fold higher at 8, 24, and 48 h post-infection vs. mock infection). Furthermore, OSM is found to co-localize with ciliated and goblet cells in hNECs infected with H3N2 influenza virus. Our findings demonstrated that increased OSM expression is implicated in CRSwNP as a possible mechanism of TJs' impairment, which can be further augmented following influenza infection via epithelial OSM expression, possibly contributing to exacerbations.

CD151, a novel host factor of nuclear export signaling in influenza virus infection.

BACKGROUND: Despite advances in our understanding of the mechanisms of influenza A virus (IAV) infection, the crucial virus-host interactions during the viral replication cycle still remain incomplete. Tetraspanin CD151 is highly expressed in the human respiratory tract, but its pathological role in IAV infection is unknown. OBJECTIVES: We sought to characterize the functional role and mechanisms of action of CD151 in IAV infection of the upper and lower respiratory tracts with H1N1 and H3N2 strains. METHODS: We used CD151-null mice in an in vivo model of IAV infection and clinical donor samples of in vitro-differentiated human nasal epithelial cells cultured at air-liquid interface. RESULTS: As compared with wild-type infected mice, CD151-null infected mice exhibited a significant reduction in virus titer and improvement in survival that is associated with pronounced host antiviral response and inflammasome activation together with accelerated lung repair. Interestingly, we show that CD151 complexes newly synthesized viral proteins with host nuclear export proteins and stabilizes microtubule complexes, which are key processes necessary for the polarized trafficking of viral progeny to the host plasma membrane for assembly. CONCLUSIONS: Our results provide new mechanistic insights into our understanding of IAV infection. We show that CD151 is a critical novel host factor of nuclear export signaling whereby the IAV nuclear export uses it to complement its own nuclear export proteins (a site not targeted by current therapy), making this regulation unique, and holds promise for the development of novel alternative/complementary strategies to reduce IAV severity.

In Vitro Model of Fully Differentiated Human Nasal Epithelial Cells Infected With Rhinovirus Reveals Epithelium-Initiated Immune Responses.

Human rhinoviruses (HRVs) are the commonest cause of the common cold. While HRV is less pathogenic than other respiratory viruses, it is frequently associated with exacerbation of chronic respiratory diseases such as rhinosinusitis and asthma. Nasal epithelial cells are the first sites of viral contact, immune initiation, and airway interconnectivity, but there are limited studies on HRV infection of nasal epithelial cells. Hence, we established a model of HRV infection of in vitro-differentiated human nasal epithelial cells (hNECs) derived from multiple individuals. Through HRV infection of hNECs, we found that HRV mainly targeted ciliated cells and preferentially induced type I and III interferon antiviral pathways. Quantitative polymerase chain reaction analysis of inflammatory genes suggested predominant type 1 immunity signaling and recruitment, with secreted CXCL9, IP-10, CXCL11, and RANTES as likely initiators of airway inflammatory responses. Additionally, we further explored HRV bidirectional release from the hNECs and identified 11 associated genes. Other HRV interactions were also identified through a systematic comparison with influenza A virus infection of hNECs. Overall, this in vitro hNEC HRV infection model provides a platform for repeatable and controlled studies of different individuals, thus providing novel insights into the roles of human nasal epithelium in HRV interaction and immune initiation.

Downregulation and Aberrant Localization of Forkhead Box J1 in Allergic Nasal Mucosa.

BACKGROUND: Forkhead box J1 (FOXJ1) plays pivotal roles in motile cilia formation. However, it remains unclear whether abnormal expression or localization of FOXJ1 in nasal mucosa tissues is associated with allergic rhinitis (AR), in which impaired mucociliary clearance is implicated. OBJECTIVE: We sought to investigate the expression and localization of FOXJ1 in inferior turbinate from patients with AR and controls. METHODS: We assayed mRNA levels of FOXJ1, DNAI1, DNALI1, and DNAH9 by using whole-genome expression array and quantitative real-time polymerase chain reaction. We elucidated the localization of FOXJ1 by using immunofluorescence assays in paraffin sections and primary single cells. Four patterns of FOXJ1 localization (normal, N; intermediate, I; mislocalization, M; absence, A) were defined. We developed a semiquantitative scoring system to elucidate their localization in 5 areas per paraffin section, with individual sections being assigned a score between 0 and 2. RESULTS: The mRNA levels of FOXJ1, DNAI1, DNALI1, and DNAH9 were significantly reduced in patients with AR compared with controls (all p < 0.05). The median (1st and 3rd quartile) of the FOXJ1 score was 0.4 (0.0 and 0.85) in patients with AR, and 0.2 (0.0 and 0.4) in controls (p < 0.05). For primary cytospin samples, the mean percentages of FOXJ1 localization patterns N, I, M, and A were 46.7, 10.0, 30.0, and 26.7% in patients with AR, and 82.5, 5.0, 5.0, and 7.5% in controls, respectively (p < 0.05). CONCLUSION: Downregulation and aberrant localization of FOXJ1 may be crucial characteristics of the allergic nasal mucosa.

Motile Ciliary Disorders in Chronic Airway Inflammatory Diseases: Critical Target for Interventions.

PURPOSE OF REVIEW: Impaired mucociliary clearance has been implicated in chronic upper and lower airway inflammatory diseases (i.e., allergic and non-allergic rhinitis, chronic rhinosinusitis with or without nasal polyps and asthma). How motile ciliary disorders (impaired ciliogenesis, ciliary beating and ultrastructural defects) are implicated in chronic airway inflammatory diseases is not fully understood. Elaboration of the role of motile ciliary disorders may serve as therapeutic targets for improving mucociliary clearance, thereby complementing contemporary disease management. RECENT FINDINGS: We have summarized the manifestations of motile ciliary disorders and addressed the underlying associations with chronic airway inflammatory diseases. A panel of established and novel diagnostic tests and therapeutic interventions are outlined. Physicians should be vigilant in screening for motile ciliary disorders, particularly in patients with co-existing upper and lower airway inflammatory diseases. Proper assessment and treatment of motile ciliary disorders may have added value to the management and prevention of chronic airway inflammatory diseases.

MicroRNA-146a induction during influenza H3N2 virus infection targets and regulates TRAF6 levels in human nasal epithelial cells (hNECs).

We have previously shown that human nasal epithelial cells (hNECs) are highly permissive cells for respiratory viruses including influenza A virus (IAV) and respiratory syncytial virus. Recent studies have indicated that microRNAs (miRNAs) are involved in virus-host relationship, and this led us to investigate its essential roles in the in vitro hNECs model derived from multiple donors. By comparing the differential expression of miRNAs upon IAV infection among animal and cell line studies, candidates were selected with focus on the initial immune response. After infection of influenza H3N2 virus, hNECs showed constant increase virus titer at 24-72h post-infection (hpi); accompanied with a significantly elevated level of miR-146a-5p at 72 hpi. The exponential elevation of progeny virus titer correlated with a key influenza sensing Toll-like receptor (TLR)7 pathway. TLR7 downstream gene transcripts, myeloid differentiation primary response gene 88 (MyD88), interferon regulator factor 7 (IRF7), and interferon-ß (IFN-ß) were significantly upregulated at 48 and 72 hpi, while interleukin-1 receptor-associated kinase 1 (IRAK1) and TNF receptor associated factor-6 (TRAF6) were unchanged. Interestingly, when miR-146a was overexpressed with miRNA mimics prior to H3N2 infection, further decreased transcripts of TRAF6, but not IRAK1, were detected. By using the in vitro hNEC model, we demonstrated that H3N2-induced miR-146a specifically targets and regulates TRAF6 expression; but not IRAK expression in the nasal epithelium. We also found that unlike the cell model studies that lead to our studies, when ran across a heterogeneous model of different individual, miRNA signals were highly varied and the expression of most miRNAs, including miR-146a-5p, was more subdued compared to homogenous cell line model, highlighting a need for a more thorough analysis of miRNA signals and targets in a model more mimicking a clinical influenza infection.

Impact of Respiratory Virus Infections in Exacerbation of Acute and Chronic Rhinosinusitis.

Rhinosinusitis (RS) is a symptomatic disease classification of many causes and is a major economic burden worldwide. It is widely accepted that RS is further classified into acute (ARS) and chronic (CRS) rhinosinusitis based on the duration of the symptoms, and that viral infection plays a large role in initiating or potentiating the disease. In this review, we examine the role of respiratory virus infection in the exacerbation of ARS and CRS. We explore the epidemiology of viral exacerbation of ARS and CRS and highlight key viruses that may cause exacerbation. We also review the current understanding of viral infections in the upper airway to further explain the putative underlying mechanisms of inflammatory events in ARS and CRS exacerbation. Advances in accurate diagnosis of the etiologic respiratory viruses of ARS and CRS symptoms which can lead to better disease management are also surveyed. In addition to the current treatments which provide symptomatic relief, we also explore the potential of harnessing existing antiviral strategies to prevent ARS and CRS exacerbation, especially with improved viral diagnostic tools to guide accurate prescription of antivirals against causative respiratory viruses.