Biology subjects

Hume, P. S.

Publications and source records attributed to Hume, P. S..

4 recordsLinked to original sources

bioRxiv2025

Spatial Heterogeneity of Macrophages in the Human Lung

RationaleTranscriptionally-defined populations of interstitial macrophages (IMs) and airspace macrophages (AMs) have recently been identified in the human lung. However, the anatomic locations occupied by these populations (i.e. alveoli, pleura, airways, or arteries) have not been fully defined. ObjectivesTo determine the distribution of transcriptionally-defined human macrophages in the major anatomical lung structures and to identify alterations in their distribution and programming induced by cigarette smoking. MethodsSingle-cell RNA sequencing was performed on lung tissue from eight human donors without pulmonary disease (four smokers and four nonsmokers). Microdissection was used to isolate distinct pulmonary anatomical structures from each lung: alveoli, pleura, airways, and arteries. Transcriptional profiles of subpopulations of interstitial macrophages (IMs) and alveolar macrophages (AMs) were analyzed based on their anatomical structure of origin and smoking status. Measurements and Main ResultsFive major IM and five AM subpopulations in human lungs are identified. We demonstrate significant differences in the accumulation patterns of each macrophage subset within anatomical structures, though each subset was detected in each. Immunofluorescent microscopy confirmed anatomical structure-specific accumulation patterns of IMs. ConclusionsIn this study, we highlight key differences in the accumulation of lung macrophage subpopulations in anatomical structures but find programming within macrophage subpopulations is largely conserved, regardless of structure of origin or smoking status. We also detect populations of inflammatory AMs and IMs which accumulate within the airways, but not the alveolar parenchyma, of human cigarette smokers. We introduce a novel three-tiered hierarchy nomenclature to distinguish transcriptionally defined human lung IM subsets as 1{degrees}) Monocyte-like vs Antigen Presenting, 2{degrees}) Quiescent vs Inflammatory, and 3{degrees}) FOLR2high vs FOLR2low. This study is the first to report the fractional accumulation of human lung macrophage subsets by lung anatomical structure. SummaryLung anatomical structure-specific single cell RNA sequencing is introduced to identify and determine the local composition of human lung leukocytes, including 5 populations of human interstitial macrophages.

immunology↗

bioRxiv2024

Requirement for Fucosyltransferase 2 in Allergic Airway Hyperreactivity and Mucus Obstruction

Mucus hypersecretion is an important pathological problem in respiratory diseases. Mucus accumulates in the airways of people with asthma, and it contributes to airflow limitation by forming plugs that occlude airways. Current treatments have minimal effects on mucus or its chief components, the polymeric mucin glycoproteins MUC5AC and MUC5B. This treatment gap reflects a poor molecular understanding of mucins that could be used to determine how they contribute to airway obstruction. Due to the prominence of glycosylation as a defining characteristic of mucins, we investigated characteristics of mucin glycans in asthma and in a mouse model of allergic asthma. Mucin fucosylation was observed in asthma, and in healthy mice it was induced as part of a mucous metaplastic response to allergic inflammation. In allergically inflamed mouse airways, mucin fucosylation was dependent on the enzyme fucosyltransferase 2 (Fut2). Fut2 gene deficient mice were protected from asthma-like airway hyperreactivity and mucus plugging. These findings provide mechanistic and translational links between observations in human asthma and a mouse model that may help improve therapeutic targeting of airway mucus.

physiology↗

bioRxiv2023

Tissue-engineered models of lung cancer premalignancy

Lung cancer is the leading global cause of cancer-related deaths. Although smoking cessation is the best preventive action, nearly 50% of all lung cancer diagnoses occur in people who have already quit smoking. Research into treatment options for these high-risk patients has been constrained to rodent models of chemical carcinogenesis, which are time-consuming, expensive, and require large numbers of animals. Here we show that embedding precision-cut lung slices within an engineered hydrogel and exposing this tissue to a carcinogen from cigarette smoke creates an in vitro model of lung cancer premalignancy. Hydrogel formulations were selected to promote early lung cancer cellular phenotypes and extend PCLS viability up to six weeks. In this study, hydrogel-embedded lung slices were exposed to the cigarette smoke derived carcinogen vinyl carbamate, which induces adenocarcinoma in mice. At six weeks, analysis of proliferation, gene expression, histology, tissue stiffness, and cellular content revealed that vinyl carbamate induced the formation of premalignant lesions with a mixed adenoma/squamous phenotype. Two putative chemoprevention agents were able to freely diffuse through the hydrogel and induce tissue-level changes. The design parameters selected using murine tissue were validated with hydrogel-embedded human PCLS and results showed increased proliferation and premalignant lesion gene expression patterns. This tissue-engineered model of human lung cancer premalignancy is the starting point for more sophisticated ex vivo models and a foundation for the study of carcinogenesis and chemoprevention strategies.

bioengineering↗

bioRxiv2022

Polymorphic KIR3DL3 expression modulates tissue-resident and innate-like T cells.

Most human killer cell immunoglobulin-like receptors (KIR) are expressed by Natural Killer (NK) cells and recognize HLA class I molecules as ligands. Uniquely, KIR3DL3 is a conserved but polymorphic inhibitory KIR recognizing a B7 family ligand, HHLA2, and is implicated for immune checkpoint targeting. Because the expression profile and biological function of KIR3DL3 remained elusive, we searched extensively for KIR3DL3 transcripts, revealing expression is highly enriched in {gamma}{delta} and CD8+ T cells rather than NK cells. These KIR3DL3 expressing cells are rare in the blood and thymus, but more common in the lungs and digestive tract. High resolution flow cytometry and single cell transcriptomics showed that peripheral blood KIR3DL3+ T cells have an activated transitional memory phenotype and are hypofunctional. The TCR usage is biased towards genes from early rearranged TCR- variable segments or V{delta}1 chains. Whereas we detected no impact of KIR3DL3 polymorphism on ligand binding, variants in the proximal promoter and at residue 86 can reduce expression. Together, we demonstrate that KIR3DL3 is upregulated in response to unconventional T cell stimulation and that individuals may vary in their ability to express KIR3DL3. These results have implications for the personalized targeting of KIR3DL3/HHLA2 checkpoint inhibition.

immunology↗