Biology subjects

Sucre, J. M. S.

Publications and source records attributed to Sucre, J. M. S..

4 recordsLinked to original sources

bioRxiv2022

Epithelial Outgrowth Through Mesenchymal Rings Drives Alveologenesis

Determining how alveoli are formed and maintained is critical to understanding lung organogenesis and regeneration after injury. While technological barriers have heretofore limited real-time observation of alveologenesis, we have now used scanned oblique plane illumination microscopy of living lung slices to observe specific cellular behaviors at high resolution over several days. Contrary to the prevailing paradigm that alveoli form by airspace subdivision via ingrowing septa, we find that alveoli form by ballooning epithelial outgrowth supported by stable mesenchymal ring structures. Our systematic analysis allowed creation of a computational model of finely-timed cellular structural changes that drive alveologenesis under normal conditions or with perturbed intercellular Wnt signaling. This new paradigm and platform can be leveraged for mechanistic studies and screening for therapies to promote lung regeneration. One-Sentence SummaryLong-term live analysis of neonatal lungs supports a dynamic epithelial outgrowth model for alveologenesis.

developmental biology↗

bioRxiv2022

β1 integrin regulates alveolar epithelial cell differentiation following injury

During alveolar repair, alveolar type 2 (AT2) epithelial cell progenitors rapidly proliferate and differentiate into flat type 1 alveolar epithelial cells. Failure of normal alveolar repair mechanisms can lead to loss of alveolar structure (emphysema) or development of fibrosis, depending on the type and severity of injury. To test if {beta}1-containing integrins are required during repair following acute injury, we administered E. coli lipopolysaccharide (LPS) by intratracheal injection to mice with a post-developmental deletion of {beta}1 integrin in AT2 cells. While control mice recovered from LPS injury without structural abnormalities, {beta}1-deficient mice had more severe inflammation and developed emphysema. In addition, recovering alveoli were repopulated with an abundance of rounded epithelial cells co-expressing type 2, type 1, and mixed intermediate cell state markers, with few mature type 1 cells. {beta}1-deficient AT2 cells showed persistently increased proliferation after injury, which was blocked by inhibiting NF-{kappa}B activation in these cells. Lineage tracing experiments revealed that {beta}1-deficient AT2 cells failed to differentiate into mature type 1 alveolar epithelial cells. Together, these findings demonstrate that functional alveolar repair after injury with terminal alveolar epithelial differentiation requires {beta}1-containing integrins.

cell biology↗

bioRxiv2022

A CXCL12 morphogen gradient uncovers lung endothelial heterogeneity and promotes distal vascular growth

In adults, there is a growing amount of data uncovering the cellular diversity of the pulmonary circulation and mechanisms governing vascular repair after injury, however, molecular and cellular mechanisms contributing to the morphogenesis and growth of the pulmonary vasculature during embryonic development are less clear. Importantly, deficits in vascular development lead to a large number of lung diseases in children, indicating a need to uncover fetal programs that promote pulmonary vascular growth. To address this, we used a transgenic mouse reporter for expression of Cxcl12, an arterial hallmark gene, and performed single-cell RNA sequencing on isolated Cxcl12-DsRed+ endothelium to assess cellular heterogeneity within pulmonary endothelium. Combining cell annotation, gene ontology analysis, and spatial transcriptomics allowed us to segregate the developing artery into spatially and functionally distinct novel subpopulations. In addition, expression of Cxcl12 suggests a morphogen gradient from arteries to capillaries, suggesting directed cell migration for pulmonary vascular development. Disruption of this gradient led to abnormal branching and pulmonary vascular hypoplasia. These data provide evidence for arterial endothelial functional heterogeneity and reveal conserved signaling mechanisms essential for pulmonary vascular development.

developmental biology↗

bioRxiv2021

Single-cell transcriptomic assessment of cellular phenotype stability in human precision-cut lung slices

Precision-cut lung slices (PCLS) are increasingly utilized for ex vivo disease modeling, but a high-resolution characterization of cellular phenotype stability in PCLS has not been reported. Comparing the single-cell transcriptomic profile of human PCLS after five days of culture to freshly isolated human lung tissue, we found striking changes in endothelial cell and alveolar epithelial cell programs, reflecting both injury and pathways activated in static culture, while immune cell frequencies and programs remained largely intact and similar to the native lung. These cellular dynamics should be considered when utilizing PCLS as a model of the human lung.

cell biology↗