Biology subjects

Sharkey, A. L.

Publications and source records attributed to Sharkey, A. L..

3 recordsLinked to original sources

bioRxiv2026

Integrin α3β1 is required for alveolar-capillary barrier formation through regulation of epithelial differentiation

Laminin-binding integrins regulate critical morphogenic processes, but their specific roles in lung development are unknown. In this study, we combined an in vivo model of epithelial 3 subunit deletion in the murine lung with a multiomics approach to investigate the role of the epithelial 3{beta}1 integrin during murine lung development. We demonstrate that 3{beta}1 integrin is dispensable for airway branching morphogenesis due to delayed epithelial expression. Instead, in vivo deletion of 3{beta}1 integrin impaired alveolar epithelial cell differentiation and disrupted alveolar-capillary barrier formation, functionally limiting gas exchange. A discontinuous alveolar BM contained abnormal collagen IV and laminin networks and widened the gap between epithelial and endothelial cells in the alveolar-capillary barrier niche. Mechanistically, mice deficient in epithelial 3{beta}1 integrin possessed an intracellular trafficking and secretion defect for BM components. Thus, integrin 3{beta}1 orchestrates the temporal maturation of alveolar epithelial cells required for organization of the alveolar-capillary barrier.

developmental biology↗

bioRxiv2025

AlveolEye: Rapid and precise lung morphometry guided by computer vision

Rigorous and reproducible evaluation of lung tissue under different conditions is necessary to interpret development, injury, and pharmacologic interventions. Common histological measurements in the distal lung include mean linear intercept (MLI) as a metric of alveolarization and airspace volume density (ASVD) as a metric of airspaces relative to tissue. Historically, these have been performed manually in a time-intensive process, with reproducible trends, but a high degree of variability between individuals. To improve the reproducibility and throughput of lung morphometry, we developed AlveolEye, an open source, semi-automated, computer vision-assisted tool that rapidly and reproducibly calculates MLI and ASVD from images of standard hematoxylin and eosin (H&E) stained tissue sections. AlveolEye-assisted MLI calculation closely aligns with manually-derived measurements for corresponding images, with preservation of trends in measurements between non-injured controls and neonatal mice subjected to two different injury models. Analyzing human tissue of varying ages suggests that the approach developed in AlveolEye is generalizable across species. Notably, AlveolEye markedly reduced the average variation across individual analyzers, with the greatest improvement in precision among individuals with the least experience in performing lung morphometry. The design of AlveolEye is intentionally semi-automated, preserving the investigators ability to assess and adjust parameters based on sample characteristics. AlveolEye facilitates efficient lung morphological measurements on larger sample sizes, allowing for greater statistical power for preclinical studies, and improves precision across individual observers, allowing for improved rigor in experimental design and execution.

developmental biology↗

bioRxiv2024

Bronchopulmonary Dysplasia with Pulmonary Hypertension Associates with Loss of Semaphorin Signaling and Functional Decrease in FOXF1 Expression

Lung injury in preterm infants leads to structural and functional respiratory deficits, with a risk for bronchopulmonary dysplasia (BPD) that in its most severe form is accompanied by pulmonary hypertension (PH). To examine cellular and molecular dynamics driving evolving BPD in humans, we performed single-cell RNA sequencing of preterm infant lungs in early stages of BPD and BPD+PH compared to term infants. Analysis of the endothelium revealed a unique aberrant capillary cell-state primarily in BPD+PH marked by ANKRD1 expression. Predictive signaling analysis identified deficits in the semaphorin guidance-cue signaling pathway and decreased expression of pro-angiogenic transcription factor FOXF1 within the alveolar parenchyma in neonatal lung samples with BPD/BPD+PH. Loss of semaphorin signaling was replicated in a murine BPD model and in humans with alveolar capillary dysplasia (ACDMPV), suggesting a mechanistic link between the developmental programs underlying BPD and ACDMPV and a critical role for semaphorin signaling in normal lung development.

genomics↗