scholarly journals Failure to Down-Regulate miR-154 Expression in Early Postnatal Mouse Lung Epithelium Suppresses Alveologenesis, with Changes in Tgf-β Signaling Similar to those Induced by Exposure to Hyperoxia

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 859 ◽  
Author(s):  
Cho-Ming Chao ◽  
Gianni Carraro ◽  
Zvonimir A. Rako ◽  
Johannes Kolck ◽  
Jamschid Sedighi ◽  
...  
Keyword(s):  
Lung Development ◽  
Mouse Lung ◽  
Alveolar Type ◽  
Lung Epithelium ◽  
Downstream Target ◽  
Developmental Program ◽  
The Common ◽  
Distal Lung ◽  
Preterm Born

Background: Bronchopulmonary dysplasia (BPD) is a lung disease of preterm born infants, characterized by alveolar simplification. MicroRNA (miR) are known to be involved in many biological and pathological processes in the lung. Although a changed expression has been described for several miR in BPD, a causal role remains to be established. Results: Our results showed that the expression level of miR-154 increases during lung development and decreases postnatally. Further, hyperoxia treatment maintains high levels of miR-154 in alveolar type 2 cells (AT2). We hypothesized that the decrease in miR-154 expression in AT2 cells is required for normal alveologenesis. To test this hypothesis, we generated a novel transgenic mouse allowing doxycycline-based miR-154 overexpression. Maintenance of miR-154 expression in the postnatal distal lung epithelium under normoxia conditions is sufficient to reproduce the hypoalveologenesis phenotype triggered by hyperoxia. Using a pull-down assay, we identified Caveolin1 as a key downstream target of miR-154. Caveolin1 protein is downregulated in response to overexpression of miR-154. This is associated with increased phosphorylation of Smad3 and Tgf-ß signaling. We found that AT2 cells overexpressing miR-154 display decreased expression of AT2 markers and increased expression of AT1 markers. Conclusion: Our results suggest that down-regulation of miR-154 in postnatal lung may function as an important physiological switch that permits the induction of the correct alveolar developmental program, while conversely, failure to down-regulate miR-154 suppresses alveolarization, leading to the common clinically observed phenotype of alveolar simplification.

scholarly journals Lung injury induces alveolar type 2 cell hypertrophy and polyploidy with implications for repair and regeneration

2021 ◽  
Author(s):  
Anthea Weng ◽  
Mariana Maciel-Herrerias ◽  
Satoshi J Watanabe ◽  
Annette S. Flozak ◽  
Lynn Welch ◽  
...  
Keyword(s):  
Lung Injury ◽  
Ex Vivo ◽  
Alveolar Type ◽  
Lung Epithelium ◽  
Post Injury ◽  
Alveolar Epithelial ◽  
Cell Hypertrophy ◽  
Alveolar Epithelial Injury ◽  
Distal Lung

Epithelial polyploidization post-injury is a conserved phenomenon, recently shown to improve barrier restoration during wound healing. Whether lung injury can induce alveolar epithelial polyploidy is not known. We show that bleomycin injury induces AT2 cell hypertrophy and polyploidy. AT2 polyploidization is also seen in short term ex vivo cultures, where AT2-to-AT1 trans-differentiation is associated with substantial binucleation due to failed cytokinesis. Both hypertrophic and polyploid features of AT2 cells can be attenuated by inhibiting the integrated stress response (ISR) using the small molecule ISRIB. These data suggest that AT2 polyploidization may be a feature of alveolar epithelial injury. As AT2 cells serve as facultative progenitors for the distal lung epithelium, a propensity for injury-induced binucleation has implications for AT2 self-renewal and regenerative potential upon re-injury, which may benefit from targeting the ISR.

scholarly journals Human embryonic lung epithelial tips are multipotent progenitors that can be expanded in vitro as long-term self-renewing organoids

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Marko Z Nikolić ◽  
Oriol Caritg ◽  
Quitz Jeng ◽  
Jo-Anne Johnson ◽  
Dawei Sun ◽  
...  
Keyword(s):  
Lung Development ◽  
Mouse Lung ◽  
Lung Epithelium ◽  
Human Embryonic Lung ◽  
Self Renewal ◽  
Embryonic Mouse ◽  
Multipotent Progenitors ◽  
Lung Epithelial

The embryonic mouse lung is a widely used substitute for human lung development. For example, attempts to differentiate human pluripotent stem cells to lung epithelium rely on passing through progenitor states that have only been described in mouse. The tip epithelium of the branching mouse lung is a multipotent progenitor pool that self-renews and produces differentiating descendants. We hypothesized that the human distal tip epithelium is an analogous progenitor population and tested this by examining morphology, gene expression and in vitro self-renewal and differentiation capacity of human tips. These experiments confirm that human and mouse tips are analogous and identify signalling pathways that are sufficient for long-term self-renewal of human tips as differentiation-competent organoids. Moreover, we identify mouse-human differences, including markers that define progenitor states and signalling requirements for long-term self-renewal. Our organoid system provides a genetically-tractable tool that will allow these human-specific features of lung development to be investigated.

GATA6 regulates differentiation of distal lung epithelium

Development ◽  
2002 ◽  
Vol 129 (9) ◽  
pp. 2233-2246 ◽  
Author(s):  
Honghua Yang ◽  
Min Min Lu ◽  
Lili Zhang ◽  
Jeffrey A. Whitsett ◽  
Edward E. Morrisey
Keyword(s):  
Gene Expression ◽  
Epithelial Cell ◽  
Surfactant Protein ◽  
Gata Factor ◽  
Lung Epithelium ◽  
Alveolar Epithelial ◽  
Distal Lung ◽  
Transgenic Embryos

GATA6 is a member of the GATA family of zinc-finger transcriptional regulators and is the only known GATA factor expressed in the distal epithelium of the lung during development. To define the role that GATA6 plays during lung epithelial cell development, we expressed a GATA6-Engrailed dominant-negative fusion protein in the distal lung epithelium of transgenic mice. Transgenic embryos lacked detectable alveolar epithelial type 1 cells in the distal airway epithelium. These embryos also exhibited increased Foxp2 gene expression, suggesting a disruption in late alveolar epithelial differentiation. Alveolar epithelial type 2 cells, which are progenitors of alveolar epithelial type 1 cells, were correctly specified as shown by normal thyroid transcription factor 1 and surfactant protein A gene expression. However, attenuated endogenous surfactant protein C expression indicated that alveolar epithelial type 2 cell differentiation was perturbed in transgenic embryos. The number of proximal airway tubules is also reduced in these embryos, suggesting a role for GATA6 in regulating distal-proximal airway development. Finally, a functional role for GATA factor function in alveolar epithelial type 1 cell gene regulation is supported by the ability of GATA6 to trans-activate the mouse aquaporin-5 promoter. Together, these data implicate GATA6 as an important regulator of distal epithelial cell differentiation and proximal airway development in the mouse.

scholarly journals Targeted Disruption of Mouse Dip2B Leads to Abnormal Lung Development and Prenatal Lethality

2020 ◽  
Vol 21 (21) ◽  
pp. 8223
Author(s):  
Rajiv Kumar Sah ◽  
Jun Ma ◽  
Fatoumata Binta Bah ◽  
Zhenkai Xing ◽  
Salah Adlat ◽  
...  
Keyword(s):  
Lung Development ◽  
Cell Types ◽  
Branching Morphogenesis ◽  
Brdu Incorporation ◽  
Mouse Lung ◽  
Alveolar Type ◽  
Type I ◽  
Lung Maturation ◽  
M Phase

Molecular and anatomical functions of mammalian Dip2 family members (Dip2A, Dip2B and Dip2C) during organogenesis are largely unknown. Here, we explored the indispensable role of Dip2B in mouse lung development. Using a LacZ reporter, we explored Dip2B expression during embryogenesis. This study shows that Dip2B expression is widely distributed in various neuronal, myocardial, endothelial, and epithelial cell types during embryogenesis. Target disruption of Dip2b leads to intrauterine growth restriction, defective lung formation and perinatal mortality. Dip2B is crucial for late lung maturation rather than early-branching morphogenesis. The morphological analysis shows that Dip2b loss leads to disrupted air sac formation, interstitium septation and increased cellularity. In BrdU incorporation assay, it is shown that Dip2b loss results in increased cell proliferation at the saccular stage of lung development. RNA-seq analysis reveals that 1431 genes are affected in Dip2b deficient lungs at E18.5 gestation age. Gene ontology analysis indicates cell cycle-related genes are upregulated and immune system related genes are downregulated. KEGG analysis identifies oxidative phosphorylation as the most overrepresented pathways along with the G2/M phase transition pathway. Loss of Dip2b de-represses the expression of alveolar type I and type II molecular markers. Altogether, the study demonstrates an important role of Dip2B in lung maturation and survival.

scholarly journals Fraction of MHCII and EpCAM expression characterizes distal lung epithelial cells for alveolar type 2 cell isolation

2017 ◽  
Vol 18 (1) ◽  
Author(s):  
Koichi Hasegawa ◽  
Atsuyasu Sato ◽  
Kazuya Tanimura ◽  
Kiyoshi Uemasu ◽  
Yoko Hamakawa ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cell Isolation ◽  
Lung Epithelial Cells ◽  
Alveolar Type ◽  
Epcam Expression ◽  
Lung Epithelial ◽  
Distal Lung

scholarly journals Fgf10-CRISPR mosaic mutants demonstrate the gene dose-related loss of the accessory lobe and decrease in the number of alveolar type 2 epithelial cells in mouse lung

PLoS ONE ◽  
2020 ◽  
Vol 15 (10) ◽  
pp. e0240333
Author(s):  
Munenori Habuta ◽  
Akihiro Yasue ◽  
Ken-ichi T. Suzuki ◽  
Hirofumi Fujita ◽  
Keita Sato ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Mouse Lung ◽  
Alveolar Type ◽  
Gene Dose ◽  
Accessory Lobe

Angiogenesis and morphogenesis of murine fetal distal lung in an allograft model

2000 ◽  
Vol 278 (5) ◽  
pp. L1000-L1007 ◽  
Author(s):  
Margaret A. Schwarz ◽  
Fangrong Zhang ◽  
John E. Lane ◽  
Susan Schachtner ◽  
Yangsun Jin ◽  
...  
Keyword(s):  
Gestational Age ◽  
Lung Development ◽  
Surfactant Protein ◽  
Structural Features ◽  
Mouse Lung ◽  
Pharmacological Agents ◽  
Embryonic Mouse ◽  
Lung Morphogenesis ◽  
Distal Lung ◽  
Immunohistochemical Techniques

Neovascularization is crucial to lung morphogenesis; however, factors determining vessel growth and formation are poorly understood. The goal of our study was to develop an allograft model that would include maturation of the distal lung, thereby ultimately allowing us to study alveolar development, including microvascular formation. We transplanted 14-day gestational age embryonic mouse lung primordia subcutaneously into the back of nude mice for 3.5–14 days. Lung morphogenesis and neovascularization were evaluated by light microscopy, in situ hybridization, and immunohistochemical techniques. Embryonic 14-day gestational age control lungs had immature structural features consistent with pseudoglandular stage of lung development. In contrast, 14 days after subcutaneous transplantation of a 14-day gestational age lung, the allograft underwent significant structural morphogenesis and neovascularization. This was demonstrated by continued neovascularization and cellular differentiation, resulting in mature alveoli similar to those noted in the 2-day postnatal neonatal lung. Confirmation of maturation of the allograft was provided by progressive type II epithelial cell differentiation as evidenced by enhanced local expression of mRNA for surfactant protein C and a threefold ( P < 0.008) increase in vessel formation as determined by immunocytochemical detection of platelet endothelial cell adhesion molecule-1 expression. Using the tyrosine kinase Flk-1 receptor ( flk-1) LacZ transgene embryos, we determined that the neovascularization within the allograft was from the committed embryonic lung endothelium. Therefore, we have developed a defined murine allograft model that can be used to study distal lung development, including neovascularization. The model may be useful when used in conjunction with an altered genetic background (knockout or knock in) of the allograft and has the further decided advantage of bypassing placental barriers for introduction of pharmacological agents or DNA directly into the lung itself.

scholarly journals SARS-CoV-2 Infection of Pluripotent Stem Cell-derived Human Lung Alveolar Type 2 Cells Elicits a Rapid Epithelial-Intrinsic Inflammatory Response

2020 ◽  
Author(s):  
Jessie Huang ◽  
Adam J. Hume ◽  
Kristine M. Abo ◽  
Rhiannon B. Werder ◽  
Carlos Villacorta-Martin ◽  
...  
Keyword(s):  
Target Genes ◽  
Human Lung ◽  
Human Model ◽  
Alveolar Type ◽  
Alveolar Cells ◽  
Protease Inhibition ◽  
Alveolar Epithelial ◽  
Distal Lung

ABSTRACTThe most severe and fatal infections with SARS-CoV-2 result in the acute respiratory distress syndrome, a clinical phenotype of coronavirus disease 2019 (COVID-19) that is associated with virions targeting the epithelium of the distal lung, particularly the facultative progenitors of this tissue, alveolar epithelial type 2 cells (AT2s). Little is known about the initial responses of human lung alveoli to SARS-CoV-2 infection due in part to inability to access these cells from patients, particularly at early stages of disease. Here we present an in vitro human model that simulates the initial apical infection of the distal lung epithelium with SARS-CoV-2, using AT2s that have been adapted to air-liquid interface culture after their derivation from induced pluripotent stem cells (iAT2s). We find that SARS-CoV-2 induces a rapid global transcriptomic change in infected iAT2s characterized by a shift to an inflammatory phenotype predominated by the secretion of cytokines encoded by NF-kB target genes, delayed epithelial interferon responses, and rapid loss of the mature lung alveolar epithelial program. Over time, infected iAT2s exhibit cellular toxicity that can result in the death of these key alveolar facultative progenitors, as is observed in vivo in COVID-19 lung autopsies. Importantly, drug testing using iAT2s confirmed an antiviral dose-response to remdesivir and demonstrated the efficacy of TMPRSS2 protease inhibition, validating a putative mechanism used for viral entry in human alveolar cells. Our model system reveals the cell-intrinsic responses of a key lung target cell to infection, providing a physiologically relevant platform for further drug development and facilitating a deeper understanding of COVID-19 pathogenesis.

scholarly journals SENP1 has an important role in lung development and influences the differentiation of alveolar type 2 cells

2018 ◽  
Author(s):  
Xue‑Qing Wan ◽  
Jia‑Yu Cai ◽  
Yue Zhu ◽  
Qiu‑Xia Wang ◽  
Hai‑Tao Zhu ◽  
...  
Keyword(s):  
Lung Development ◽  
Alveolar Type
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