Severity-associated transcriptional signatures in the respiratory mucosa during human paediatric RSV infection
File(s)
Author(s)
Barnes, Megan
Type
Thesis
Abstract
Bronchiolitis driven by respiratory syncytial virus (RSV), and other respiratory viruses, is a major cause of hospitalisation in infants. Despite this burden, we lack specific therapeutics in part due to an incomplete understanding of the mechanisms of severe disease. In the upper respiratory tract of infants under the age of two, the primary mechanism of RSV-induced disease severity is thought to be a deficient antiviral response via diminished production of interferons (IFNs). Using a NanoString transcriptomic array, 785 genes were analysed across innate and adaptive immune responses to identify dysregulated pathways between moderate (n=30) and severe (n=27) all-cause bronchiolitis, as well as moderate (n=14) and severe (n=13) severe RSV-induced bronchiolitis. A deficient IFN response was measured in more severe infection in both all-cause and RSV-bronchiolitis cohorts, as well as a significant upregulation of IL36A. Production of mucosal IL-36α and -γ was also evident at the protein level. IL-36α and -γ are members of the IL-1 family of cytokines, which are associated with neutrophilic inflammation in respiratory morbidities such as chronic obstructive pulmonary disorder. Using a 3D human nasal epithelial cell culture, representing a healthy, fully differentiated nasal epithelium, RSV-infection induced IL36 expression, but the mucosal proteins could not be detected until neutrophils were added to the culture. Neutrophils cleave and activate IL-36 proteins, and their presence in co-culture with an RSV-infected epithelium caused the mucosal production of IL-36α. Performing single cell RNA-sequencing on nasal brushings from healthy (n=2) and RSV-infected (n=5) infants did not reveal which cell types were responsible for IL-36 production but did reveal strong IFN-associated induction by neutrophils, but not the nasal epithelium, in severe RSV-induced bronchiolitis.
Version
Open Access
Date Issued
2024-06-10
Date Awarded
01/10/2024
License URL
Advisor
Thwaites, Ryan
Openshaw, Peter
Nadel, Simon
Strickson, Sam
Romero-Ros, Xavier
Cohen, Suzanne
Sponsor
Biotechnology and Biological Sciences Research Council (Great Britain)
AstraZeneca (Firm)
Grant Number
G01134
Publisher Department
National Heart & Lung Institute
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)