Clare Lloyd

Primary human basal bronchial epithelial cells (HBECs) are an important population of progenitor cells capable of self-renewal and differentiation to maintain airway homeostasis. In air-liquid interface (ALI) culture, HBECs undergo mucociliary differentiation, providing a robust physiologic model to evaluate novel therapeutics such as in vitro-transcribed messenger RNA (IVT-mRNA). However, the impact of IVT-mRNA delivery on the differentiation potential of basal HBECs remains poorly characterised. Poly(beta amino) ester (PBAE) nanoparticles have demonstrated effective airway delivery of IVT-mRNA in various preclinical studies. Here, we aimed to understand the impact of PBAE-mediated mRNA transfection on basal HBEC differentiation at the ALI. We investigated IVT-mRNA encoding the ciliogenesis transcription factor Forkhead box J1 (FOXJ1) as a model tool for transient overexpression in primary basal HBECs and characterised its subsequent impact on epithelial integrity and differentiation at the ALI. PBAE-mediated delivery of FOXJ1 mRNA to submerged primary HBECs resulted in approximately 50% FOXJ1-positive cells and transient upregulation of key ciliogenesis-related genes, including DNALI1 and RSPH9. Following 28 days of differentiation at the ALI, FOXJ1- or reporter mRNA-transfected cultures displayed normal epithelial morphology, with tight junction and differentiation markers, proportions of secretory and ciliated cells, and ciliary ultrastructure comparable to those of non-transfected controls. These data indicate that PBAE-mediated IVT-mRNA delivery can transiently increase encoded protein expression in basal primary HBECs without impeding mucociliary differentiation.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was a global pandemic where infected individuals experienced mild or severe disease. Unfortunately, some patients who experienced severe disease also had lasting abnormalities. The lung microbiome of 38 adult coronavirus disease 2019 (COVID-19) patients with persistent respiratory symptoms and/or radiological abnormalities was analysed. The aim was to investigate whether the lasting radiological abnormalities reported in this cohort were associated with an altered airway. Thirty-six bronchoalveolar lavage fluid samples from patients underwent 16S rRNA gene amplicon sequencing and were compared to 28 non-fibrotic control samples from a previously published study. COVID-19 patients had statistically significantly greater number of genera but at uneven abundances, though not statistically significant compared to non-fibrotic controls. Permutational ANOVA (PERMANOVA) suggested that COVID-19 can influence the lung microbiome composition after accounting for multivariate dispersion. Further analysis showed differences in the relative abundances of Actinomyces , Neisseria , Haemophilus , Rothia and Gemella . Indicator species analysis showed that a COVID-19 lung microbiome profile could be driven in part by differences in Fusobacterium , Actinomyces , Catonella , Oribacterium and Mycobacterium . Associations with clinical parameters were lacking apart from CT lung opacification, which revealed a significant negative association with the number of genera. Differential abundance analysis with MaAsLin2 pointed towards Porphyromonas as a potential explaining genus, though this was not significant after post hoc corrections. DESeq2 revealed enriched oral taxa in the BAL samples, suggesting potential oral-translocation reflective of a disease state. Our findings suggest that individuals with persistent radiological abnormalities following SARS-CoV-2 infection have experienced subtle shifts in their microbiome profile, but these are not strongly associated with clinical phenotypes and, therefore, unlikely of significance.

Biological sex has a significant impact on how the immune system develops and responds to foreign and self‐antigens. Sex differences exist in innate and adaptive immune cells, both at homeostasis and in the context of infection and inflammatory diseases such as asthma, cancer, and autoimmune disorders. Women generate stronger immune responses and are more susceptible to developing autoimmune conditions, while males are more prone to acute viral infections and developing certain cancers. Some immunological differences persist throughout life, while others emerge only after puberty and before reproductive senescence. Additionally, environmental exposures can affect the influence of biological sex in regulating immune function. This is particularly pertinent at mucosal surfaces such as the lungs, where lung immune defenses are constantly exposed to foreign material during respiration. Consequently, environmental factors together with genetics, age and sex hormones play a vital role in governing lung tissue immune responses between the sexes. In this context, we highlight studies that support the need for considering sex as an important biological variable in lung immunological research. This knowledge will provide a benchmark for understanding sex‐driven immunological mechanisms that underpin disease development and may inform new avenues targeted for generating sex‐specific therapies in lung disease.

Hormonal disruptions are associated with poor asthma control in females, yet how these phenomena are linked remains unknown. Here, we investigated distinct allergen-induced immune responses between the sexes during maturation. By 6 weeks of life, female mice exposed to the aeroallergen house dust mite (HDM) from postnatal day 7 exhibited stronger type 2 (T2) immune responses and higher lung interleukin-33 (IL-33) than males. IL-33 administration to HDM-sensitized males was sufficient to augment T2 immunity and up-regulated epidermal growth factor receptor (EGFR) on T helper 2 (T _H 2) cells. EGFR inhibition abrogated T2 cytokine production in vitro. In vivo, EGFR inhibition reduced T2 immunity in females only, thereby abolishing any sex differences. 17β-estradiol (E ₂ ) heightened lung Il33 expression and T2 responses of HDM-sensitized males, akin to levels in females. EGFR’s ability to drive sex differences in lung T2 responses downstream of E ₂ and IL-33 may link hormonal disruptions to poor asthma control.

Background: Epithelial-immune cell interactions are crucial in the regulation of pulmonary immune responses. Emerging evidence suggests that cell populations lining the airways may play a pivotal role in the pathogenesis of idiopathic pulmonary fibrosis (IPF), a disease characterised by progressive scarring of the lung parenchyma. We profiled the cellular landscape of the airway mucosal niche in incident cases of IPF to understand early-stage events contributing to disease development. Methods: Single-cell RNA-sequencing was used to explore cellular heterogeneity in proximal airway brushings from seven healthy controls and nine patients with newly diagnosed IPF. In-depth bioinformatics analysis was used to interrogate changes in cell populations and cell-cell communication in IPF patients compared to controls. Results: We show a relative increase in the abundance of airway macrophage subsets in IPF compared to healthy controls, and disease-specific changes in their transcriptional profile. Increased frequency of airway macrophages and proliferating macrophages was associated with more extensive disease at baseline quantified by the composite physiological index and radiological severity of traction bronchiectasis. Monocyte-derived macrophages were significantly enriched at baseline in IPF patients who had disease progression at 12 months. Using CellChat we exposed differences in cell-cell communication between airway epithelial cells, airway macrophages and T cells in IPF. We identified dysregulation in signalling pathways such as SEMA3, ANXA1 and DESMOSOME which modulate airway epithelial-macrophage interactions, potentially driving disease pathology. Conclusions: Airway epithelial cells and macrophages may play a key role in orchestrating the early immunopathology of IPF, and these data support further exploration of novel, airway-focused therapeutic targets in IPF.

Early microbial colonization influences respiratory disease risk, yet mechanisms remain unclear. In a prospective birth cohort of 256 infants, we profiled bacterial, fungal, and viral communities in the upper airway and assessed local immune gene expression longitudinally and systemic gene expression at 1 year. Bacterial populations, not fungal or viral, correlated most strongly with immune development during the first 3 months, coinciding with composition shifts and immune-related gene expression changes, including interferon and adaptive immunity pathways. In contrast, the mycobiome and resident viruses showed no significant coevolution with host immunity. By 1 year, infants who previously wheezed displayed an upper airway microbiota enriched in Haemophilus influenzae and Moraxella , accompanied by a distinct local and systemic immune gene signature featuring elevated classical monocyte-related genes. These findings reveal a specific link between early-life bacterial dysbiosis, monocyte-related immunity, and wheezing onset, suggesting potential targets for early intervention in respiratory disease.

Innate lymphoid cells (ILCs) fulfill critical roles in maintenance of tissue-specific homeostasis but have also been implicated in disease pathology when dysregulated. Although they are broadly classified into three core subsets, it is increasingly apparent that ILCs exhibit plasticity in response to microenvironmental factors. Accurate and holistic evaluation of the ILC landscape is critical to understanding the contribution of ILCs to disease pathology. Using high-parameter flow cytometry, we comprehensively interrogated the phenotypic and functional diversity of ILCs in healthy volunteers and patients with severe asthma (SA), assessing the reciprocity between peripheral blood and airway compartments and dissecting the impact of anti–IL-5/5Rα biologics on these responses. We identified substantial heterogeneity and putative plasticity in human ILC responses, highlighting inherent limitations of conventional enumeration strategies. Deep phenotypic and functional profiling demonstrated a distinct sexual dimorphism in ILC responses in patients with SA. Females displayed an elevated abundance of circulating ILC progenitors, ILC1s, and ILC3s, whereas males presented with diminished ILC2s compared with respective healthy controls. Circulating ILC progenitors inversely correlated with testosterone concentrations. Moreover, we identified a reciprocal influx of all core ILC subsets into the airways of patients with SA, with unbiased multisource clustering identifying a relationship between elevated airway ILC2s and reduced lung function. Last, we showed that anti–IL-5/5Rα biologics largely ablated airway ILC type 2 cytokine production without affecting core ILC subset abundance in the peripheral blood or airways, identifying a potential mechanism whereby anti–IL-5/5Rα biologics alleviate clinical disease in patients with SA.

This paper investigates the persistent underrepresentation of Black heritage researchers and academics at UK Higher Education Institutions in Science, Technology, Engineering, Maths, and Medicine (STEMM), with a focus on Biomedical Research where possible. Despite decades of policy development, research, and advocacy, 0.6% of STEMM professors are Black, falling to zero in certain disciplines. Are the structural barriers that exclude Black researchers at every stage of the STEMM pipeline? Research culture influences how research is conducted, communicated, and how researchers are supported. Academic progression depends on research, funding, publications, teaching, and leadership, and the criteria are often unequally applied. Evidence highlights Black researchers’ experiences of exclusion, racial harassment, and opaque advancement processes; moreover, funding disparities further entrench inequality. Data reveal that Black researchers account for less than 1% of fellowship holders and Principal Investigators. Additionally, without institutional support, Black researchers and academics are routinely excluded from the research culture and economy. Black professors’ underrepresentation is not simply a pipeline issue but a result of intersecting failures in recruitment, funding, and academic culture. Grassroots initiatives offer community support but come at a cost, the “Minority Tax”, which is unpaid labour that diverts time from career-building activities. Representation matters for students, knowledge production, and institutional legitimacy. Therefore, systemic reforms are urgently required. Research funders and institutions must implement transparent, equitable policies that enable Black researchers to not only enter but also thrive and lead within the UK research ecosystem.