contact-free-co-culture-model-for-study-innate-immune-cell-activation

Contact-Free Co-Culture Model for the Study of Innate Immune Cell Activation During Respiratory Virus Infection

The early interactions between the nasal epithelial layer and the innate immune cells during viral infections remains an under-explored area. The ...

National University of Singapore

National University Health System

In this study, we evaluated the effects of targeted sinonasal surgery on nasal and maxillary sinus airflow patterns. A patient, who underwent right balloon sinuplasty and left uncinectomy for recurrent maxillary sinus barometric pressure, and concomitant septoplasty and bilateral inferior turbinate reduction for deviated nasal septum and inferior turbinate hypertrophy, was selected. Two 3D models representing both pre- and post-operative sinonasal morphology were constructed. The models were then used to evaluate nasal and maxillary sinus airflow patterns during respiration at ventilation rates of 7.5 L/min, 15 L/min and 30 L/min using computational fluid dynamics. The results showed that septoplasty and inferior turbinate reduction increased the nasal volume by 13.6%. The airflow patterns in the nasal cavity showed reasonably decreased resistance and slightly more even flow partitioning after the operation. Maxillary sinus ventilation significantly increased during inspiration in the left sinus after uncinectomy, and during expiration in right sinus after balloon sinuplasty. This study demonstrates computational fluid dynamics simulation is a tool in the investigation of outcomes after targeted, minimally invasive sinonasal surgery.

Assessment of airflow ventilation in human nasal cavity and maxillary sinus before and after targeted sinonasal surgery: a numerical case study.

Concomitant maxillofacial, laryngeal and cervical spine injuries may occur after high-energy accidents. Although this presentation is uncommon, the multiple injuries may compromise airway, breathing, circulation, and neurologic function. We identified 8 adult trauma patients admitted to the National University Hospital with the concomitant injuries. We reviewed the patient data and existing literature to identify the important factors that must be considered for management. Seven resulted from high velocity accidents, whereas 1 was assaulted. An algorithm that prioritizes in-tandem diagnosis and acute management of the adult trauma patient with maxillofacial, laryngeal, and cervical spine trauma was developed. The first priority is to assess airway, breathing, and circulation with cervical spine immobilization. Early diagnosis of patients with severe laryngeal injury, confirmation by video endoscopy, and establishing a surgical airway prevents airway obstruction or even a laryngotracheal dissociation. Urgent computed tomography scans of the head and neck are essential for definitive diagnosis and surgical planning for the 3 injuries. Prudent sequencing of surgery is important to avoid complications and to achieve better functional outcomes. 

An Algorithm for the Management of Concomitant Maxillofacial, Laryngeal, and Cervical Spine Trauma.

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.

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

Upper airway inflammatory diseases are associated with abnormal expression of nasal epithelial forkhead-box J1 (FOXJ1) which regulates motile cilia formation. We sought to investigate whether aberrant FOXJ1 localizations correlate with the disease severity and the co-existence of allergic rhinitis (AR) or asthma in patients with nasal polyps (NPs).

Aberrant localization of FOXJ1 correlates with the disease severity and comorbidities in patients with nasal polyps.

The human nasal epithelium is the primary site of exposure to influenza virus, the initiator of host responses to influenza and the resultant pathologies. Influenza virus may cause serious respiratory infection resulting in major complications, as well as severe impairment of the airways. Here, we elucidated the global transcriptomic changes during H3N2 infection of human nasal epithelial cells from multiple individuals. Using RNA sequencing, we characterized the differentially-expressed genes and pathways associated with changes occurring at the nasal epithelium following infection. We used in vitro differentiated human nasal epithelial cell culture model derived from seven different donors who had no concurrent history of viral infections. Statistical analysis highlighted strong transcriptomic signatures significantly associated with 24 and 48 h after infection, but not at the earlier 8-h time point. In particular, we found that the influenza infection induced in the nasal epithelium early and altered responses in interferon gamma signaling, B-cell signaling, apoptosis, necrosis, smooth muscle proliferation, and metabolic alterations. These molecular events initiated at the infected nasal epithelium may potentially adversely impact the airway, and thus the genes we identified could serve as potential diagnostic biomarkers or therapeutic targets for influenza infection and associated disease management.

RNA Sequencing of H3N2 Influenza Virus-Infected Human Nasal Epithelial Cells from Multiple Subjects Reveals Molecular Pathways Associated with Tissue Injury and Complications.

 Nasal polyp (NP) is a chronic upper airway inflammatory disease that is frequently triggered by defective host-defense. However, the mechanisms underlying the impaired barrier function such as cilia-mediated mucociliary clearance remain poorly understood.  To assess ciliary ultrastructural and ciliogenesis marker expression and the phenotypes of ciliated cells in NP.  NP biopsy samples were obtained from 97 NP patients and inferior turbinate from 32 healthy controls. Immunofluorescence staining, quantitative polymerase chain reaction, and single-cell cytospin staining were performed. We classified the patterns of radial spoke head protein () 1, 4A (), 9 (), and dynein axonemal heavy chain 5 () localization. A semi-quantitative scoring system was developed to assess their expression patterns and associations with ciliogenesis markers [centrosomal protein 110 () and forkhead box j1 ()].  Median scores of , ,  and  were significantly higher in NP than in healthy controls, particularly in eosinophilic NPs. Expression pattern scores of , ,  and  correlated positively with each other in both groups. In primary-cell specimens, abnormal expression patterns were significantly more common in NP. The total fluorescence intensity of  and  was significantly higher in NPs and correlated positively with expression pattern scores of , ,  and . A trend towards lengthened cilia was observed in NP.  In the chronic airway inflammatory milieu, the up-regulated ciliogenesis correlates with the abnormal expression of ciliary ultrastructural markers (i.e., ) in NP (particularly eosinophilic NP).

An Integrated Analysis of Radial Spoke Head and Outer Dynein Arm Protein Defects and Ciliogenesis Abnormality in Nasal Polyps.

Obstructive sleep apnea is a prevalent sleep disorder characterized by partial or complete obstruction of the upper airway. Continuous positive airway pressure is the first-line therapy for most patients, but compliance is often poor. Alternative treatment options such as mandibular advancement devices, positional therapy and surgical interventions including upper airway stimulation target different levels and patterns of obstruction with varying degrees of success. Drug-induced sleep endoscopy enables visualization of upper airway obstruction under conditions mimicking sleep. In an era of precision medicine, this additional information may facilitate better decision-making when prescribing alternative treatment modalities, with the hope of achieving better compliance and/or success rates. This review discusses the current knowledge and evidence on the role of drug-induced sleep endoscopy in the non-positive airway pressure management of obstructive sleep apnea.

The Emerging Role of Drug-Induced Sleep Endoscopy in the Management of Obstructive Sleep Apnea.

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.

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.

Respiratory viral infections are one of the main drivers of development and exacerbation for chronic airway inflammatory diseases. Increased viral susceptibility and impaired mucociliary clearance are often associated with chronic airway inflammatory diseases and served as risk factors of exacerbations. However, the links between viral susceptibility, viral clearance, and impaired mucociliary functions are unclear. Therefore, the objective of this study is to provide the insights into the effects of improper clearance of respiratory viruses from the epithelium following infection, and their resulting persistent activation of antiviral response, on mucociliary functions.

Article	Year
Assessment of airflow ventilation in human nasal cavity and maxillary sinus before and after targeted sinonasal surgery: a numerical case study. Respiratory physiology & neurobiology\| PubMed ID: 24418355	2014
An Algorithm for the Management of Concomitant Maxillofacial, Laryngeal, and Cervical Spine Trauma. Annals of plastic surgery\| PubMed ID: 27070668	2016
Downregulation and Aberrant Localization of Forkhead Box J1 in Allergic Nasal Mucosa. International archives of allergy and immunology\| PubMed ID: 29635245	2018
Aberrant localization of FOXJ1 correlates with the disease severity and comorbidities in patients with nasal polyps. Allergy, asthma, and clinical immunology : official journal of the Canadian Society of Allergy and Clinical Immunology\| PubMed ID: 30459817	2018
RNA Sequencing of H3N2 Influenza Virus-Infected Human Nasal Epithelial Cells from Multiple Subjects Reveals Molecular Pathways Associated with Tissue Injury and Complications. Cells\| PubMed ID: 31461941	2019
An Integrated Analysis of Radial Spoke Head and Outer Dynein Arm Protein Defects and Ciliogenesis Abnormality in Nasal Polyps. Frontiers in genetics\| PubMed ID: 31798623	2019
The Emerging Role of Drug-Induced Sleep Endoscopy in the Management of Obstructive Sleep Apnea. Clinical and experimental otorhinolaryngology\| PubMed ID: 33092317	2020
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. PLoS pathogens\| PubMed ID: 33284849	2020
Host Antiviral Response Suppresses Ciliogenesis and Motile Ciliary Functions in the Nasal Epithelium. Frontiers in cell and developmental biology\| PubMed ID: 33409274	2020

Mark Thong

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