Abrogation of mesenchyme-specific TGF-β signaling results in lung malformation with prenatal pulmonary cysts in mice

The TGF-β signaling pathway plays a pivotal role in controlling organogenesis during fetal development. Although the role of TGF-β signaling in promoting lung alveolar epithelial growth has been determined, mesenchymal TGF-β signaling in regulating lung development has not been studied in vivo due to a lack of genetic tools for specifically manipulating gene expression in lung mesenchymal cells. Therefore, the integral roles of TGF-β signaling in regulating lung development and congenital lung diseases are not completely understood. Using a Tbx4 lung enhancer-driven Tet-On inducible Cre transgenic mouse system, we have developed a mouse model in which lung mesenchyme-specific deletion of TGF-β receptor 2 gene (Tgfbr2) is achieved. Reduced airway branching accompanied by defective airway smooth muscle growth and later peripheral cystic lesions occurred when lung mesenchymal Tgfbr2 was deleted from embryonic day 13.5 to 15.5, resulting in postnatal death due to respiratory insufficiency. Although cell proliferation in both lung epithelium and mesenchyme was reduced, epithelial differentiation was not significantly affected. Tgfbr2 downstream Smad-independent ERK1/2 may mediate these mesenchymal effects of TGF-β signaling through the GSK3β--β-catenin--Wnt canonical pathway in fetal mouse lung. Our study suggests that Tgfbr2-mediated TGF-β signaling in prenatal lung mesenchyme is essential for lung development and maturation, and defective TGF-β signaling in lung mesenchyme may be related to abnormal airway branching morphogenesis and congenital airway cystic lesions.

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The Lung Vasculature: A Driver or Passenger in Lung Branching Morphogenesis?

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2020.623868 ◽

2021 ◽

Vol 8 ◽

Author(s):

Yelda Pakize Kina ◽

Ali Khadim ◽

Werner Seeger ◽

Elie El Agha

Keyword(s):

Lung Development ◽

Branching Morphogenesis ◽

Mouse Lung ◽

Physical Factors ◽

Airway Epithelial ◽

Leading Role ◽

Rate Limiting Step ◽

Airway Tree ◽

Rate Limiting ◽

Airway Branching

Multiple cellular, biochemical, and physical factors converge to coordinate organogenesis. During embryonic development, several organs such as the lung, salivary glands, mammary glands, and kidneys undergo rapid, but intricate, iterative branching. This biological process not only determines the overall architecture, size and shape of such organs but is also a pre-requisite for optimal organ function. The lung, in particular, relies on a vast surface area to carry out efficient gas exchange, and it is logical to suggest that airway branching during lung development represents a rate-limiting step in this context. Against this background, the vascular network develops in parallel to the airway tree and reciprocal interaction between these two compartments is critical for their patterning, branching, and co-alignment. In this mini review, we present an overview of the branching process in the developing mouse lung and discuss whether the vasculature plays a leading role in the process of airway epithelial branching.

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The kinome of lung branching morphogenesis — A systems approach to identify phosphoregulators of mouse lung development

Developmental Biology ◽

10.1016/j.ydbio.2008.05.134 ◽

2008 ◽

Vol 319 (2) ◽

pp. 505

Author(s):

Carsten Schnatwinkel ◽

Angela Minic ◽

Lee Niswander

Keyword(s):

Lung Development ◽

Systems Approach ◽

Branching Morphogenesis ◽

Mouse Lung ◽

Lung Branching

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Regulation of retinoic acid signaling during lung morphogenesis

Development ◽

10.1242/dev.127.14.3057 ◽

2000 ◽

Vol 127 (14) ◽

pp. 3057-3067 ◽

Cited By ~ 1

Author(s):

S. Malpel ◽

C. Mendelsohn ◽

W.V. Cardoso

Keyword(s):

Retinoic Acid ◽

Lung Development ◽

Branching Morphogenesis ◽

Initial Stage ◽

Signaling Center ◽

Distal Lung ◽

Immature Lung ◽

Airway Branching ◽

Correct Expression

Little is known about how retinoic acid (RA) synthesis, utilization and metabolism are regulated in the embryonic lung and how these activities relate to lung pattern formation. Here we report that early lung bud formation and subsequent branching morphogenesis are characterized by distinct stages of RA signaling. At the onset of lung development RA signaling is ubiquitously activated in primary buds, as shown by expression of the major RA-synthesizing enzyme, RALDH-2 and activation of a RARE-lacZ transgene. Nevertheless, further airway branching appears to require downregulation of RA pathways by decreased synthesis, increased RA degradation in the epithelium via P450RAI-mediated metabolism, and inhibition of RA signaling in the mesenchyme by COUPTF-II expression. These mechanisms controlling local RA signaling may be critical for normal branching, since we show that manipulating RA levels in vitro to maintain RA signaling activated as in the initial stage, leads to an immature lung phenotype characterized by failure to form typical distal buds. We show that this phenotype likely results from RA interfering with the establishment of a distal signaling center, altering levels and distribution of Fgf10 and Bmp4, genes that are essential for distal lung formation. Furthermore, RA upregulates P450RAI expression, suggesting the presence of feedback mechanisms controlling RA availability. Our study illustrates the importance of regional mechanisms that control RA availability and utilization for correct expression of pattern regulators and normal morphogenesis during lung development.

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Mouse Lung Organoid Responses to Reduced, Increased, and Cyclic Stretch

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00310.2020 ◽

2021 ◽

Author(s):

Rashika Joshi ◽

Matthew R. Batie ◽

Qiang Fan ◽

Brian Michael Varisco

Keyword(s):

Lung Development ◽

Histone Deacetylases ◽

Cyclic Strain ◽

Cyclic Stretch ◽

Mouse Lung ◽

Proliferating Cells ◽

Double Positive ◽

Cross Sectional ◽

Static Stretch

Most lung development occurs in the context of cyclic stretch. Alteration of the mechanical microenvironment is a common feature of many pulmonary diseases with congenital diaphragmatic hernia (CDH) and fetal tracheal occlusion (FETO, a therapy for CDH) being extreme examples with changes in lung structure, cell differentiation and function. To address limitations in cell culture and in vivo mechanotransductive models we developed two mouse lung organoid (mLO) mechanotransductive models using postnatal day 5 (PND5) mouse lung CD326-positive cells and fibroblasts subjected to increased, decreased, and cyclic strain. In the first model, mLOs were exposed to forskolin (FSK) and/or disrupted (DIS) and evaluated at 20 hours. mLO cross-sectional area changed by +59%, +24% and -68% in FSK, control, and DIS mLOs respectively. FSK-treated organoids had twice as many proliferating cells as other organoids. In the second model, 20 hours of 10.25% biaxial cyclic strain increased the mRNAs of lung mesenchymal cell lineages compared to static stretch and no stretch. Cyclic stretch increased TGF-β and integrin-mediated signaling with upstream analysis indicating roles for histone deacetylases, microRNAs, and long non-coding RNAs. Cyclic stretch mLOs increased αSMA- and αSMA-PDGFRα-double positive cells compared to no stretch and static stretch mLOs. In this PND5 mLO mechanotransductive model, cell proliferation is increased by static stretch, and cyclic stretch induces mesenchymal gene expression changes important in postnatal lung development.

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Fibroblast growth factor 10 (FGF10) and branching morphogenesis in the embryonic mouse lung

Development ◽

10.1242/dev.124.23.4867 ◽

1997 ◽

Vol 124 (23) ◽

pp. 4867-4878 ◽

Cited By ~ 74

Author(s):

S. Bellusci ◽

J. Grindley ◽

H. Emoto ◽

N. Itoh ◽

B.L. Hogan

Keyword(s):

Growth Factor ◽

Fibroblast Growth Factor ◽

Lung Development ◽

Expression Patterns ◽

Branching Morphogenesis ◽

Mouse Lung ◽

Fibroblast Growth ◽

Embryonic Mouse ◽

Fibroblast Growth Factor 10

During mouse lung morphogenesis, the distal mesenchyme regulates the growth and branching of adjacent endoderm. We report here that fibroblast growth factor 10 (Fgf10) is expressed dynamically in the mesenchyme adjacent to the distal buds from the earliest stages of lung development. The temporal and spatial pattern of gene expression suggests that Fgf10 plays a role in directional outgrowth and possibly induction of epithelial buds, and that positive and negative regulators of Fgf10 are produced by the endoderm. In transgenic lungs overexpressing Shh in the endoderm, Fgf10 transcription is reduced, suggesting that high levels of SHH downregulate Fgf10. Addition of FGF10 to embryonic day 11.5 lung tissue (endoderm plus mesenchyme) in Matrigel or collagen gel culture elicits a cyst-like expansion of the endoderm after 24 hours. In Matrigel, but not collagen, this is followed by extensive budding after 48–60 hours. This response involves an increase in the rate of endodermal cell proliferation. The activity of FGF1, FGF7 and FGF10 was also tested directly on isolated endoderm in Matrigel culture. Under these conditions, FGF1 elicits immediate endodermal budding, while FGF7 and FGF10 initially induce expansion of the endoderm. However, within 24 hours, samples treated with FGF10 give rise to multiple buds, while FGF7-treated endoderm never progresses to bud formation, at all concentrations of factor tested. Although exogenous FGF1, FGF7 and FGF10 have overlapping activities in vitro, their in vivo expression patterns are quite distinct in relation to early branching events. We conclude that, during early lung development, localized sources of FGF10 in the mesoderm regulate endoderm proliferation and bud outgrowth.

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A critical role for miR-142 in alveolar epithelial lineage formation in mouse lung development

Cellular and Molecular Life Sciences ◽

10.1007/s00018-019-03067-8 ◽

2019 ◽

Vol 76 (14) ◽

pp. 2817-2832 ◽

Cited By ~ 2

Author(s):

Amit Shrestha ◽

Gianni Carraro ◽

Nicolas Nottet ◽

Ana Ivonne Vazquez-Armendariz ◽

Susanne Herold ◽

...

Keyword(s):

Lung Development ◽

Critical Role ◽

Mouse Lung ◽

Alveolar Epithelial

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

International Journal of Molecular Sciences ◽

10.3390/ijms21218223 ◽

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.

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LSC Abstract – Alpha8 integrin deficiency alters branching morphogenesis and alveolarization during mouse lung development

10.1183/13993003.congress-2016.op8 ◽

2016 ◽

Author(s):

Tiziana Patrizia Cremona ◽

Johannes Schittny

Keyword(s):

Lung Development ◽

Branching Morphogenesis ◽

Mouse Lung

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Increased alveolar soluble annexin V promotes lung inflammation and fibrosis

European Respiratory Journal ◽

10.1183/09031936.00002115 ◽

2015 ◽

Vol 46 (5) ◽

pp. 1417-1429 ◽

Cited By ~ 9

Author(s):

Susan Buckley ◽

Wei Shi ◽

Wei Xu ◽

Mark R. Frey ◽

Rex Moats ◽

...

Keyword(s):

Conditioned Medium ◽

Transforming Growth Factor ◽

Human Fibroblasts ◽

Annexin V ◽

Transforming Growth Factor Β ◽

Lavage Fluid ◽

Mitogen Activated Protein Kinase ◽

Mouse Lung ◽

Alveolar Epithelial

The causes underlying the self-perpetuating nature of idiopathic pulmonary fibrosis (IPF), a progressive and usually lethal disease, remain unknown. We hypothesised that alveolar soluble annexin V contributes to lung fibrosis, based on the observation that human IPF bronchoalveolar lavage fluid (BALF) containing high annexin V levels promoted fibroblast involvement in alveolar epithelial wound healing that was reduced when annexin V was depleted from the BALF.Conditioned medium from annexin V-treated alveolar epithelial type 2 cells (AEC2), but not annexin V per se, induced proliferation of human fibroblasts and contained pro-fibrotic, IPF-associated proteins, as well as pro-inflammatory cytokines that were found to correlate tightly (r>0.95) with annexin V levels in human BALF. ErbB2 receptor tyrosine kinase in AECs was activated by annexin V, and blockade reduced the fibrotic potential of annexin V-treated AEC-conditioned medium. In vivo, aerosol delivery of annexin V to mouse lung induced inflammation, fibrosis and increased hydroxyproline, with activation of Wnt, transforming growth factor-β, mitogen-activated protein kinase and nuclear factor-κB signalling pathways, as seen in IPF.Chronically increased alveolar annexin V levels, as reflected in increased IPF BALF levels, may contribute to the progression of IPF by inducing the release of pro-fibrotic mediators.

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