Identifying Bacterial Airways Infection in Stable Severe Asthma Using Oxford Nanopore Sequencing Technologies

Jabeen, Maisha; Sanderson, Nicholas; Foster, Dona; Crook, Derrick W.; Cane, Jennifer; Borg, Catherine; Connolly, Clare; Thulborn, Samantha; Pavord, Ian; Klenerman, Paul; Street, Teresa L; Hinks, Timothy S. C.

doi:10.1128/spectrum.02279-21

Cited by 12 publications

(13 citation statements)

References 39 publications

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“…Although NTHi is often considered rather innocuous, our data support the growing body of data that this pathogen has a relatively unique ability to persist within the airways and drive ongoing and recurrent neutrophilic inflammation in type-2 low asthma, and therefore is likely to merit more attention by clinicians. This is a common clinical scenario and indeed using Nanopore long-read sequencing we have recently identified NTHi in the lower airways in 35% of a pilot cohort of patients with severe asthma ( Jabeen et al., 2022 ). Further larger cohorts are required to define the prevalence of this and other specific potentially pathogenic bacteria in well-defined cohorts with airways disease.…”

Section: Discussionmentioning

confidence: 94%

Epithelial immune activation and intracellular invasion by non-typeable Haemophilus influenzae

Brown

Morgan

Donachie

et al. 2023

Front. Cell. Infect. Microbiol.

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Type-2 low asthma affects 30-50% of people with severe asthma and includes a phenotype characterized by sputum neutrophilia and resistance to corticosteroids. Airways inflammation in type-2 low asthma or COPD is potentially driven by persistent bacterial colonization of the lower airways by bacteria such as non-encapsulated Haemophilus influenzae (NTHi). Although pathogenic in the lower airways, NTHi is a commensal of the upper airways. It is not known to what extent these strains can invade airway epithelial cells, persist intracellularly and activate epithelial cell production of proinflammatory cytokines, and how this differs between the upper and lower airways. We studied NTHi infection of primary human bronchial epithelial cells (PBECs), primary nasal epithelial cells (NECs) and epithelial cell lines from upper and lower airways. NTHi strains differed in propensity for intracellular and paracellular invasion. We found NTHi was internalized within PBECs at 6 h, but live intracellular infection did not persist at 24 h. Confocal microscopy and flow cytometry showed NTHi infected secretory, ciliated and basal PBECs. Infection of PBECs led to induction of CXCL8, interleukin (IL)-1β, IL-6 and TNF. The magnitude of cytokine induction was independent of the degree of intracellular invasion, either by differing strains or by cytochalasin D inhibition of endocytosis, with the exception of the inflammasome-induced mediator IL-1β. NTHi-induced activation of TLR2/4, NOD1/2 and NLR inflammasome pathways was significantly stronger in NECs than in PBECs. These data suggest that NTHi is internalized transiently by airway epithelial cells and has capacity to drive inflammation in airway epithelial cells.

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Section: Discussionmentioning

confidence: 94%

Epithelial immune activation and intracellular invasion by non-typeable Haemophilus influenzae

Brown

Morgan

Donachie

et al. 2023

Front. Cell. Infect. Microbiol.

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“…In pediatric asthma, small studies have reported increased frequency of IL-17 + MAIT cells in bronchoalveolar lavage (142) and blood (143) of patients presenting with severe exacerbations, however no comparisons were made with health when sampling the lower airway (142). In adult disease Haemophilus influenzae has emerged as the commonest potentially pathogenic organism in the airway, associated with sputum neutrophilia and altered microbial diversity, namely reduction in Streptococcus, Gemella and Porphyromonas taxa (135,136,144,145). In a large bronchoscopy study no evidence of increased IL-17A in serum, sputum or BAL was found in asthma nor was there an increase in IL-17 + T cell populations (Th17 or gdT cells).…”

Section: The Lower Airwaymentioning

confidence: 99%

MAIT cells and the microbiome

Jabeen

Hinks

2023

Front. Immunol.

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Mucosal associated invariant T (MAIT) cells are innate-like T lymphocytes, strikingly enriched at mucosal surfaces and characterized by a semi-invariant αβ T cell receptor (TCR) recognizing microbial derived intermediates of riboflavin synthesis presented by the MHC-Ib molecule MR1. At barrier sites MAIT cells occupy a prime position for interaction with commensal microorganisms, comprising the microbiota. The microbiota is a rich source of riboflavin derived antigens required in early life to promote intra-thymic MAIT cell development and sustain a life-long population of tissue resident cells. A symbiotic relationship is thought to be maintained in health whereby microbes promote maturation and homeostasis, and in turn MAIT cells can engage a TCR-dependent “tissue repair” program in the presence of commensal organisms conducive to sustaining barrier function and integrity of the microbial community. MAIT cell activation can be induced in a MR1-TCR dependent manner or through MR1-TCR independent mechanisms via pro-inflammatory cytokines interleukin (IL)-12/-15/-18 and type I interferon. MAIT cells provide immunity against bacterial, fungal and viral pathogens. However, MAIT cells may have deleterious effects through insufficient or exacerbated effector activity and have been implicated in autoimmune, inflammatory and allergic conditions in which microbial dysbiosis is a shared feature. In this review we summarize the current knowledge on the role of the microbiota in the development and maintenance of circulating and tissue resident MAIT cells. We also explore how microbial dysbiosis, alongside changes in intestinal permeability and imbalance between pro- and anti-inflammatory components of the immune response are together involved in the potential pathogenicity of MAIT cells. Whilst there have been significant improvements in our understanding of how the microbiota shapes MAIT cell function, human data are relatively lacking, and it remains unknown if MAIT cells can conversely influence the composition of the microbiota. We speculate whether, in a human population, differences in microbiomes might account for the heterogeneity observed in MAIT cell frequency across mucosal sites or between individuals, and response to therapies targeting T cells. Moreover, we speculate whether manipulation of the microbiota, or harnessing MAIT cell ligands within the gut or disease-specific sites could offer novel therapeutic strategies.

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“…Moreover, it is unclear how common this trait is, or to what extent heterogeneity of the microbiome matters to predicting treatment response. In a pilot study of metagenomic analysis using quantitative PCR and Oxford nanopore sequencing, we identified H. influenzae as the dominant airway pathogen in eight out of 23 people with severe asthma [ 158 ]. The presence of Haemophilus at high abundance was significantly and invariably associated with sputum neutrophilia, as was the presence of M. catarrhalis , in two out of 23 samples.…”

Section: Clinical Application: Efficacy Of Macrolides In Asthmamentioning

confidence: 99%

Non-typeableHaemophilus influenzaeairways infection: the next treatable trait in asthma?

et al. 2022

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Asthma is a complex, heterogeneous condition that affects over 350 million people globally. It is characterised by bronchial hyperreactivity and airways inflammation. A subset display marked airway neutrophilia, associated with worse lung function, higher morbidity and poor response to treatment. In these individuals, recent metagenomic studies have identified persistent bacterial infection, particularly with non-encapsulated strains of the Gram-negative bacterium Haemophilus influenzae. Here we review knowledge of non-typeable H. influenzae (NTHi) in the microbiology of asthma, the immune consequences of mucosal NTHi infection, various immune evasion mechanisms, and the clinical implications of NTHi infection for phenotyping and targeted therapies in neutrophilic asthma. Airway neutrophilia is associated with production of neutrophil chemokines and proinflammatory cytokines in the airways, including interleukin (IL)-1β, IL-6, IL-8, IL-12, IL-17A and tumour necrosis factor. NTHi adheres to and invades the lower respiratory tract epithelium, inducing the NLR family pyrin domain containing 3 (NLRP3) and absent in melanoma 2 (AIM2) inflammasomes. NTHi reduces expression of tight-junction proteins, impairing epithelial integrity, and can persist intracellularly. NTHi interacts with rhinoviruses synergistically via upregulation of intracellular cell adhesion molecule 1 and promotion of a neutrophilic environment, to which NTHi is adapted. We highlight the clinical relevance of this emerging pathogen and its relevance for the efficacy of long-term macrolide therapy in airways diseases, we identify important unanswered questions and we propose future directions for research.

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Identifying Bacterial Airways Infection in Stable Severe Asthma Using Oxford Nanopore Sequencing Technologies

Abstract: The human airways were once thought sterile in health. Now metagenomic techniques suggest bacteria may be present, but their role in asthma is not understood.

Cited by 12 publications

References 39 publications

Epithelial immune activation and intracellular invasion by non-typeable Haemophilus influenzae

Epithelial immune activation and intracellular invasion by non-typeable Haemophilus influenzae

MAIT cells and the microbiome

Non-typeableHaemophilus influenzaeairways infection: the next treatable trait in asthma?

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