Mast cell activation disrupts interactions between endothelial cells and pericytes during early life allergic asthma
Régis Joulia, Franz Puttur, Helen Stölting, William J. Traves, Lewis J. Entwistle, Anastasia Voitovich, Minerva Garcia Martín, May Al-Sahaf, Katie Bonner, Elizabeth Scotney, Philip L. Molyneaux, Richard J. Hewitt, Simone A. Walker, Laura Yates, Sejal Saglani, Clare M. Lloyd
Régis Joulia, Franz Puttur, Helen Stölting, William J. Traves, Lewis J. Entwistle, Anastasia Voitovich, Minerva Garcia Martín, May Al-Sahaf, Katie Bonner, Elizabeth Scotney, Philip L. Molyneaux, Richard J. Hewitt, Simone A. Walker, Laura Yates, Sejal Saglani, Clare M. Lloyd
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Research Article Inflammation Vascular biology

Mast cell activation disrupts interactions between endothelial cells and pericytes during early life allergic asthma

Abstract

Allergic asthma generally starts during early life and is linked to substantial tissue remodeling and lung dysfunction. Although angiogenesis is a feature of the disrupted airway, the impact of allergic asthma on the pulmonary microcirculation during early life is unknown. Here, using quantitative imaging in precision-cut lung slices (PCLSs), we report that exposure of neonatal mice to house dust mite (HDM) extract disrupts endothelial cell/pericyte interactions in adventitial areas. Central to the blood vessel structure, the loss of pericyte coverage was driven by mast cell (MC) proteases, such as tryptase, that can induce pericyte retraction and loss of the critical adhesion molecule N-cadherin. Furthermore, spatial transcriptomics of pediatric asthmatic endobronchial biopsies suggests intense vascular stress and remodeling linked with increased expression of MC activation pathways in regions enriched in blood vessels. These data provide previously unappreciated insights into the pathophysiology of allergic asthma with potential long-term vascular defects.

Authors

Régis Joulia, Franz Puttur, Helen Stölting, William J. Traves, Lewis J. Entwistle, Anastasia Voitovich, Minerva Garcia Martín, May Al-Sahaf, Katie Bonner, Elizabeth Scotney, Philip L. Molyneaux, Richard J. Hewitt, Simone A. Walker, Laura Yates, Sejal Saglani, Clare M. Lloyd

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Figure 4

MC granules induce pericyte retraction and cleavage of surface N-cadherin.

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MC granules induce pericyte retraction and cleavage of surface N-cadheri...
MCs were sensitized overnight with anti-DNP IgE then placed on a layer of pericytes (stained with CMTMR) and stimulated with increasing concentrations of DNP-BSA for 24 hours. (A) Schematic depicting the coculture experiment between primary mouse lung MCs and pericytes. (B) Images of unstimulated or stimulated (100 ng/ml DNP-BSA) pericyte/MC cocultures stained for DAPI (yellow), CMTMR (purple), PDGFRβ (blue), and avidin (green, MC granules). White boxes indicate the areas zoomed in showing examples of resting or degranulated MCs. Scale bars: 15 μm. Representative of 3 independent experiments. (C) Frequency of degranulated MCs. n = 6–8 images from 3 independent experiments. (D) Number of pericytes per field of view. n = 15 images from 3 independent experiments. (E) Pericyte volume determined using the cell tracer CMTMR. n = 253–299 pericytes from 3 independent experiments. (F) Avidin signal on small pericytes (<17,000 μm3) and large pericytes (>45,000 μm3) showing that small pericytes exhibit more MC granule staining on their surfaces. n = 18–46 from 3 independent experiments. (G) Representative images of F-actin (green) and N-cadherin (magenta) pericyte expression in the presence of degranulated MCs or control. Scale bars: 50 μm. Representative of 3 independent experiments. (H–I) F-actin (H, n = 98–144) and surface N-cadherin (I, n = 98–144) MFI on pericytes. Three independent experiments. Data are represented as means ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001, 1-way ANOVA followed by Tukey’s post hoc test (C, D, E, H, and I); 2-tailed Student’s t test (F).