Project description:Recent studies suggest that chronic inflammation and immune dysregulation in the local tissues and systemically play a critical role in the pathophysiology of long COVID. Here, we report a role for nasal epithelium in mediating inflammation in a subset of long COVID patients. We demonstrate impaired barrier function of nasal epithelial cells, inadequate wound healing potential, and nasal cell hypersensitivity along with a persistent inflammatory state in long COVID. These inflamed structural cells activate type 1 innate lymphoid cells in the blood of long COVID patients and propagate systemic inflammation. We demonstrated the importance of understanding the immunological mechanisms driving long COVID to develop effective treatments. We highlight the critical role of the nasal epithelial barrier and the interplay between epithelial cells and ILCs in maintaining mucosal homeostasis and contributing to chronic inflammation in long COVID.
Project description:The nasal epithelium is the primary initial site of SARS-CoV-2 entry in the human body. Since much of the molecular detail defining coronavirus entry and replication was derived from non-nasal cell lines, it remains unclear how SARS-CoV-2 overcomes the physical nasal mucus and periciliary mucin layers to infect and spread through the nasal epithelium. Using air-liquid interface cultured primary nasal epithelial cells, we observed that SARS-CoV-2 attaches to motile cilia during the initial stage of infection. Depletion of cilia inhibited SARS-CoV-2, as well as respiratory syncytial virus and parainfluenza virus infection, suggesting a widely-used ciliary mechanism for respiratory viral entry. Using electron and immunofluorescence microscopy, we further observed that SARS-CoV-2 progeny virions attached to airway microvilli 24 hours post infection and triggered the formation of apically extended and highly branched microvilli that organize viral egress from the microvillar base back into the mucus layer, supporting a model of virus dispersion throughout airway tissue via mucociliary transport. Chemical perturbation of microvillus formation severely impaired viral egress and subsequent spread. Phosphoproteomic analyses indicate that virally-triggered microvillar branching is linked to the p21-activated kinase 1 and 4 (PAK1/4) signaling pathway and viral infection is impaired by PAK1/4 kinase inhibitors. Our work provides insight into the mechanisms by which SARS-CoV-2 and potentially many respiratory viruses penetrate the physical nasal epithelium barrier, a first line of defense against pathogens, thus revealing a new view of the motile cilia and microvilli as critical host factors required for viral entry and egress.
Project description:The nasal epithelium is an important target site for chemically-induced toxicity and carcinogenicity. Human epidemiological investigations and experimental laboratory animal studies show that the nasal olfactory epithelium is selectively damaged by inhalation exposure to several chemicals, including vinyl acetate and hydrogen sulfide. The reason for the relative sensitivity of the nasal olfactory epithelium is not known. To better understand and predict the response of the nasal epithelium to inhaled xenobiotics, gene expression profiles from naÑve male and female Sprague-Dawley rats were constructed. Epithelial cells were manually collected from the nasal septum, naso- and maxillo-turbinates, and ethmoid turbinates of 9 male and 9 female rats. Gene expression analysis was performed using the Affymetrix Rat Genome 430 2.0 microarray. Gene ontology enrichment analysis identified several functional categories including xenobiotic metabolism, cell cycle, apoptosis, and ion channel/transport with significantly different expression between tissue types. Surprisingly, there were few gender differences in gene expression. This baseline data will contribute to our understanding of the normal physiology and selectivity of the nasal epithelial cellsâ response to inhaled environmental toxicants. Experiment Overall Design: To better understand and predict the response of the nasal epithelium to inhaled xenobiotics, gene expression profiles from naÑve male and female Sprague-Dawley rats were constructed. Epithelial cells were manually collected from the nasal septum, naso- and maxillo-turbinates, and ethmoid turbinates of 9 male and 9 female rats. Gene expression analysis was performed using the Affymetrix Rat Genome 430 2.0 microarray.
Project description:COVID-19 symptoms range from mild to severe illness; the cause for this differential response to infection remains unknown. Unraveling the immune mechanisms acting at different levels of the colonization process might be key to understand these differences. We carried out a multi-tissue (nasal, buccal and blood) gene expression analysis of immune-related genes from patients affected by different COVID-19 severities, and healthy controls.
Project description:Understanding on pathogenesis of COVID-19 is rapidly growing, but primary target cells of SARS-CoV-2 infection is still not known. Here, we performed single cell RNA sequencing on human nasal swab from COVID-19 patient to investigate the expression patterns of host cell entry factors of SARS-CoV-2.
Project description:Post-acute sequelae of COVID-19 (PASC) represent an emerging global crisis. However, quantifiable risk-factors for PASC and their biological associations are poorly resolved. We executed a deep multi-omic, longitudinal investigation of 309 COVID-19 patients from initial diagnosis to convalescence (2-3 months later), integrated with clinical data, and patient-reported symptoms. We resolved four PASC-anticipating risk factors at the time of initial COVID-19 diagnosis: type 2 diabetes, SARS-CoV-2 RNAemia, Epstein-Barr virus viremia, and specific autoantibodies. In patients with gastrointestinal PASC, SARS-CoV-2-specific and CMV-specific CD8+ T cells exhibited unique dynamics during recovery from COVID-19. Analysis of symptom-associated immunological signatures revealed coordinated immunity polarization into four endotypes exhibiting divergent acute severity and PASC. We find that immunological associations between PASC factors diminish over time leading to distinct convalescent immune states. Detectability of most PASC factors at COVID-19 diagnosis emphasizes the importance of early disease measurements for understanding emergent chronic conditions and suggests PASC treatment strategies.
Project description:The nasal epithelium is an important target site for chemically-induced toxicity and carcinogenicity. Human epidemiological investigations and experimental laboratory animal studies show that the nasal olfactory epithelium is selectively damaged by inhalation exposure to several chemicals, including vinyl acetate and hydrogen sulfide. The reason for the relative sensitivity of the nasal olfactory epithelium is not known. To better understand and predict the response of the nasal epithelium to inhaled xenobiotics, gene expression profiles from naїve male and female Sprague-Dawley rats were constructed. Epithelial cells were manually collected from the nasal septum, naso- and maxillo-turbinates, and ethmoid turbinates of 9 male and 9 female rats. Gene expression analysis was performed using the Affymetrix Rat Genome 430 2.0 microarray. Gene ontology enrichment analysis identified several functional categories including xenobiotic metabolism, cell cycle, apoptosis, and ion channel/transport with significantly different expression between tissue types. Surprisingly, there were few gender differences in gene expression. This baseline data will contribute to our understanding of the normal physiology and selectivity of the nasal epithelial cells’ response to inhaled environmental toxicants. Keywords: Comparative
Project description:Hydrogen sulfide (H2S) is a naturally occurring gas that is also associated with several industries. The potential for widespread human inhalation exposure to this toxic gas is recognized as a public health concern. The nasal epithelium is particularly susceptible to H2S-induced pathology. Injury to and regeneration of the nasal respiratory mucosa occurred in animals with ongoing H2S exposure suggesting that the regenerated respiratory epithelium undergoes an adaptive response and becomes resistant to further H2S induced toxicity. To better understand this adaptive response, twenty-four naive 10-week old male Sprague-Dawley rats were exposed to air or 200 ppm H2S in a nose-only exposure system for 3h/d for 1 or 5 consecutive days. Nasal respiratory epithelial cells at the site of injury and regeneration were laser capture microdissected and gene expression profiles were generated at time 3h, 6h, 24h, and 144h post initial exposure using the Affymetrix Rat Genome 430 2.0 microarray. Gene ontology enrichment analysis identified early gene changes in such functional categories as signal transduction, inflammatory/defense response, cell cycle, and response to oxidative stress. Later gene changes occurred in categories involved in cell cycle, DNA repair, transport, and micro-tubule-based movement. These data contribute to our understanding of the nasal epithelial cells? response to inhaled environmental toxicants. A better understanding of the H2S cytotoxicity mechanism will improve human risk assessment. Experiment Overall Design: Twenty-four naive 10-week old male Sprague-Dawley rats were exposed to air or 200 ppm H2S in a nose-only exposure system for 3h/d for 1 or 5 consecutive days. Nasal respiratory epithelial cells at the site of injury and regeneration were laser capture microdissected and gene expression profiles were generated at time 3h, 6h, 24h, and 144h post initial exposure using the Affymetrix Rat Genome 430 2.0 microarray.
Project description:Smoking is the leading cause of lung cancer death, although only a small percentage of smokers develop the disease. Cigarette smoke exposure is known to cause a field of injury in cells throughout the respiratory tract, and while these airway epithelial cells are morphologically normal, they can undergo genetic alterations in response to cigarette smoke exposure. We used microarrays to analyze the gene expression of epithelial cells in the extrathoracic epithelium, specifically nasal and buccal epithelium, to see if these cells underwent similar genetic alterations in response to tobacco exposure as seen in bronchial epithelial cells as has been previously reported. Experiment Overall Design: Buccal and nasal epithelial cell samples were collected from healthy current and never smokers. RNA was isolated from these samples and hybridized to Affymetrix microarrays. Gene expression from never smokers was compared to never smoker gene expression from bronchial epithelium as well as expression data from other tissues to determine commonalities in expression patterns in normal extra- and intra-thoracic samples. In addition, gene expression from smokers and nonsmokers was compared in bronchial, nasal, and buccal epithelium to determine similarities in gene expression in these tissues in response to cigarette smoker exposure.
Project description:Background: In asthma, airway epithelium remodeling can already be detected during childhood, and epithelial cells are more susceptible to virus and oxidative stress. Their exact role in natural history and severity of children allergic respiratory disease remains however surprisingly unexplored. Aim: To analyze dysfunctions of epithelium in dust mite allergic respiratory disease (rhinitis ± asthma) in children. Methods: Expression profilings of nasal epithelial cells collected by brushing were performed on Affymetrix Hugene 1.0 ST arrays. All allergic patients were sensitized to dust mite. 19 patients had an isolated allergic rhinitis (AR). 14 patients had AR associated with asthma. Patients were compared to 12 controls, their severity and control being assessed according to NAEPP and ARIA criteria. Infections by respiratory viruses were excluded by real-time PCR measurements. Results: 61 probes were able to distinguish allergic rhinitis children from healthy controls. A majority of these probes was under the control of Th2 cytokines, as evidenced by parallel experiments performed on primary cultures of nasal epithelial cells. In uncontrolled asthmatic patients, we observed not only an enhanced expression of these Th2-responsive transcripts, but also a down-regulation of interferon-responsive genes. Conclusion: Our study identifies a Th2 driven epithelial phenotype common to all dust mite allergic children. Besides, it suggests that epithelium is involved in the severity of the disease. Expression profiles observed in uncontrolled asthmatic patients suggest that severity of asthma is linked at the same time to atopy and to impaired viral response. Nasal epithelium gene expression profiling of dust mite allergic children with isolated rhinitis, rhinitis associated with asthma and controls. 38 samples classified in 4 categories : 14 isolated rhinitis (R), 6 rhinitis with uncontrolled asthma (UA), 7 rhinitis with controlled asthma (CA) and 11 healthy subjects (C )