Biology subjects

Plosa, E. J.

Publications and source records attributed to Plosa, E. J..

5 recordsLinked to original sources

bioRxiv2024

Endothelial β1 Integrins are Necessary for Microvascular Function and Glucose Uptake

Microvascular insulin delivery to myocytes is rate limiting for the onset of insulin-stimulated muscle glucose uptake. The structural integrity of capillaries of the microvasculature is regulated, in part, by a family of transmembrane adhesion receptors known as integrins, which are composed of an and {beta} subunit. The integrin {beta}1 (itg{beta}1) subunit is highly expressed in endothelial cells (EC). EC itg{beta}1 is necessary for the formation of capillary networks during embryonic during development and its knockdown in adult mice blunts the reactive hyperemia that manifests during ischemia reperfusion. In this study we investigated the contribution of skeletal muscle EC itg{beta}1 in microcirculatory function and glucose uptake. We hypothesized that loss of EC itg{beta}1 would impair microvascular hemodynamics and glucose uptake during insulin stimulation, creating delivery-mediated insulin resistance. An itg{beta}1 knockdown mouse model was developed to avoid lethality of embryonic gene knockout and the deteriorating health resulting from early post-natal inducible gene deletion. We found that mice with (itg{beta}1fl/flSCLcre) and without (itg{beta}1fl/fl) inducible stem cell leukemia cre recombinase (SLCcre) expression at 10 days post cre induction have comparable exercise tolerance and pulmonary and cardiac functions. We quantified microcirculatory hemodynamics using intravital microscopy and the ability of mice to respond to the high metabolic demands of insulin-stimulated muscle using a hyperinsulinemic-euglycemia clamp. We show that itg{beta}1fl/flSCLcre mice compared to itg{beta}1fl/fl littermates have, i) deficits in capillary flow rate, flow heterogeneity, and capillary density; ii) impaired insulin-stimulated glucose uptake despite sufficient transcapillary insulin efflux; and iii) reduced insulin-stimulated glucose uptake due to perfusion-limited glucose delivery. Thus, EC itg{beta}1 is necessary for microcirculatory function and to meet the metabolic challenge of insulin stimulation.

physiology↗

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↗

bioRxiv2021

A Single Cell Atlas of Lung Development

Lung organogenesis requires precisely timed shifts in the spatial organization and function of parenchymal cells, especially during the later stages of lung development. To investigate the mechanisms governing lung parenchymal dynamics during development, we performed a single cell RNA sequencing (scRNA-seq) time-series yielding 92,238 epithelial, endothelial, and mesenchymal cells across 8 time points from embryonic day 12 (E12) to postnatal day 14 (P14) in mice. We combined new computational analyses with RNA in situ hybridization to explore transcriptional velocity, fate likelihood prediction, and spatiotemporal localization of cell populations during the transition between the saccular and alveolar stages. We interrogated this atlas to illustrate the complexity of type 1 pneumocyte function during the saccular and alveolar stages, and we demonstrate an integrated view of the cellular dynamics during lung development.

developmental biology↗

bioRxiv2020

Age-related expression of SARS-CoV-2 priming protease TMPRSS2 in the developing lung

The SARS-CoV-2 novel coronavirus global pandemic (COVID-19) has led to millions of cases and hundreds of thousands of deaths around the globe. While the elderly appear at high risk for severe disease, hospitalizations and deaths due to SARS-CoV-2 among children have been relatively rare. Integrating single-cell RNA sequencing (scRNA-seq) of the developing mouse lung with temporally-resolved RNA-in-situ hybridization (ISH) in mouse and human lung tissue, we found that expression of SARS-CoV-2 Spike protein primer TMPRSS2 was highest in ciliated cells and type I alveolar epithelial cells (AT1), and TMPRSS2 expression was increased with aging in mice and humans. Analysis of autopsy tissue from fatal COVID-19 cases revealed SARS-CoV-2 RNA was detected most frequently in ciliated and secretory cells in the airway epithelium and AT1 cells in the peripheral lung. SARS-CoV-2 RNA was highly colocalized in cells expressing TMPRSS2. Together, these data demonstrate the cellular spectrum infected by SARS-CoV-2 in the lung epithelium, and suggest that developmental regulation of TMPRSS2 may underlie the relative protection of infants and children from severe respiratory illness.

developmental biology↗