Regulation of retinoic acid signaling during lung morphogenesis

Development ◽  
2000 ◽  
Vol 127 (14) ◽  
pp. 3057-3067 ◽  
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.

scholarly journals In vitro models of fetal lung development to enhance research into congenital lung diseases

2021 ◽  
Author(s):  
Soichi Shibuya ◽  
Jessica Allen-Hyttinen ◽  
Paolo De Coppi ◽  
Federica Michielin
Keyword(s):  
Lung Development ◽  
Lung Diseases ◽  
Ex Vivo ◽  
Fetal Lung ◽  
Branching Morphogenesis ◽  
In Vitro Models ◽  
Normal Lung ◽  
Novel Therapeutic Strategies ◽  
Pseudoglandular Stage

Abstract Purpose This paper aims to build upon previous work to definitively establish in vitro models of murine pseudoglandular stage lung development. These can be easily translated to human fetal lung samples to allow the investigation of lung development in physiologic and pathologic conditions. Methods Lungs were harvested from mouse embryos at E12.5 and cultured in three different settings, i.e., whole lung culture, mesenchyme-free epithelium culture, and organoid culture. For the whole lung culture, extracted lungs were embedded in Matrigel and incubated on permeable filters. Separately, distal epithelial tips were isolated by firstly removing mesothelial and mesenchymal cells, and then severing the tips from the airway tubes. These were then cultured either in branch-promoting or self-renewing conditions. Results Cultured whole lungs underwent branching morphogenesis similarly to native lungs. Real-time qPCR analysis demonstrated expression of key genes essential for lung bud formation. The culture condition for epithelial tips was optimized by testing different concentrations of FGF10 and CHIR99021 and evaluating branching formation. The epithelial rudiments in self-renewing conditions formed spherical 3D structures with homogeneous Sox9 expression. Conclusion We report efficient protocols for ex vivo culture systems of pseudoglandular stage mouse embryonic lungs. These models can be applied to human samples and could be useful to paediatric surgeons to investigate normal lung development, understand the pathogenesis of congenital lung diseases, and explore novel therapeutic strategies.

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

2021 ◽  
Author(s):  
Qing Miao ◽  
Hui Chen ◽  
Yongfeng Luo ◽  
Joanne Chiu ◽  
Ling Chu ◽  
...  
Keyword(s):  
Lung Development ◽  
Muscle Growth ◽  
Branching Morphogenesis ◽  
Mouse Lung ◽  
Cystic Lesions ◽  
Alveolar Epithelial ◽  
Pulmonary Cysts ◽  
Β Receptor ◽  
Airway Branching

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.

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

Development ◽  
1997 ◽  
Vol 124 (23) ◽  
pp. 4867-4878 ◽  
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.

scholarly journals Chondroitin sulfate proteoglycans are required for lung growth and morphogenesis in vitro

2003 ◽  
Vol 285 (6) ◽  
pp. L1323-L1336 ◽  
Author(s):  
John M. Shannon ◽  
Kathleen McCormick-Shannon ◽  
Michael S. Burhans ◽  
Xiaofei Shangguan ◽  
Kalpana Srivastava ◽  
...  
Keyword(s):  
Chondroitin Sulfate ◽  
Lung Development ◽  
Sodium Chlorate ◽  
Surfactant Protein ◽  
Branching Morphogenesis ◽  
Clara Cell ◽  
Normal Lung ◽  
Lung Growth ◽  
Isolated Lung

Proteoglycans (PGs) have been shown to play a key role in the development of many tissues. We have investigated the role of sulfated PGs in early rat lung development by treating cultured tissues with 30 mM sodium chlorate, a global inhibitor of PG sulfation. Chlorate treatment disrupted growth and branching of embryonic day 13 lung explants. Isolated lung epithelium (LgE) migrated toward and invaded lung mesenchyme (LgM), and chlorate irreversibly suppressed this response. Chlorate also inhibited migration of LgE toward beads soaked in FGF10. Chlorate severely decreased branching morphogenesis in tissue recombinants consisting of LgM plus either LgE or tracheal epithelium (TrE) and decreased expression of surfactant protein C gene ( SP-C). Chlorate also reduced bone morphogenetic protein-4 expression in cultured tips and recombinants but had no effect on the expression of clara cell 10-kDa protein ( CC10), sonic hedgehog ( Shh), FGF10, and FGF receptor 2IIIb. Chlorate reduced the growth of LgE in mesenchyme-free culture but did not affect SP-C expression. In contrast, chlorate inhibited both rudiment growth and the induction of SP-C in mesenchyme-free cultured TrE. Treatment of lung tips and tissue recombinants with chondroitinase ABC abolished branching morphogenesis. Chondroitinase also suppressed growth of TrE in mesenchyme-free culture. Chondroitinase treatment, however, had no effect on the induction of SP-C expression in any of these cultures. These results demonstrate the overall importance of sulfated PGs to normal lung development and demonstrate a dynamic role for chondroitin sulfate PGs in embryonic lung growth and morphogenesis.

Iroquoisgenes influence proximo-distal morphogenesis during rat lung development

2006 ◽  
Vol 290 (4) ◽  
pp. L777-L789 ◽  
Author(s):  
Minke van Tuyl ◽  
Jason Liu ◽  
Freek Groenman ◽  
Ross Ridsdale ◽  
Robin N. N. Han ◽  
...  
Keyword(s):  
Lung Development ◽  
Cell Formation ◽  
Surfactant Protein ◽  
Branching Morphogenesis ◽  
Secretory Protein ◽  
Clara Cell ◽  
Fgf Receptor ◽  
Clara Cell Secretory Protein ◽  
Morphogenetic Protein

Lung development is a highly regulated process directed by mesenchymal-epithelial interactions, which coordinate the temporal and spatial expression of multiple regulatory factors required for proper lung formation. The Iroquois homeobox ( Irx) genes have been implicated in the patterning and specification of several Drosophila and vertebrate organs, including the heart. Herein, we investigated whether the Irx genes play a role in lung morphogenesis. We found that Irx1– 3 and Irx5 expression was confined to the branching lung epithelium, whereas Irx4 was not expressed in the developing lung. Antisense knockdown of all pulmonary Irx genes together dramatically decreased distal branching morphogenesis and increased distention of the proximal tubules in vitro, which was accompanied by a reduction in surfactant protein C-positive epithelial cells and an increase in β-tubulin IV and Clara cell secretory protein positive epithelial structures. Transmission electron microscopy confirmed the proximal phenotype of the epithelial structures. Furthermore, antisense Irx knockdown resulted in loss of lung mesenchyme and abnormal smooth muscle cell formation. Expression of fibroblast growth factors (FGF) 1, 7, and 10, FGF receptor 2, bone morphogenetic protein 4, and Sonic hedgehog (Shh) were not altered in lung explants treated with antisense Irx oligonucleotides. All four Irx genes were expressed in Shh- and Gli2-deficient murine lungs. Collectively, these results suggest that Irx genes are involved in the regulation of proximo-distal morphogenesis of the developing lung but are likely not linked to the FGF, BMP, or Shh signaling pathways.

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

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.

Effect of chemical stabilizers of hypoxia-inducible factors on early lung development

2007 ◽  
Vol 293 (3) ◽  
pp. L557-L567 ◽  
Author(s):  
Freek A. Groenman ◽  
Martin Rutter ◽  
Jinxia Wang ◽  
Isabella Caniggia ◽  
Dick Tibboel ◽  
...  
Keyword(s):  
Lung Development ◽  
Hypoxia Inducible Factor ◽  
Iron Chelator ◽  
Branching Morphogenesis ◽  
Vegf Receptor ◽  
Low Oxygen ◽  
Prolyl Hydroxylases ◽  
Protein Levels ◽  
Terminal Buds ◽  
Airway Branching

Low oxygen stimulates pulmonary vascular development and airway branching and involves hypoxia-inducible factor (HIF). HIF is stable and initiates expression of angiogenic factors under hypoxia, whereas normoxia triggers hydroxylation of the HIF-1α subunit by prolyl hydroxylases (PHDs) and subsequent degradation. Herein, we investigated whether chemical stabilization of HIF-1α under normoxic (20% O2) conditions would stimulate vascular growth and branching morphogenesis in early lung explants. Tie2-LacZ (endothelial LacZ marker) mice were used for visualization of the vasculature. Embryonic day 11.5 (E11.5) lung buds were dissected and cultured in 20% O2 in the absence or presence of cobalt chloride (CoCl2, a hypoxia mimetic), dimethyloxalylglycine (DMOG; a nonspecific inhibitor of PHDs), or desferrioxamine (DFO; an iron chelator). Vascularization was assessed by X-gal staining, and terminal buds were counted. The fine vascular network surrounding the developing lung buds seen in control explants disappeared in CoCl2- and DFO-treated explants. Also, epithelial branching was reduced in the explants treated with CoCl2 and DFO. In contrast, DMOG inhibited branching but stimulated vascularization. Both DFO and DMOG increased nuclear HIF-1α protein levels, whereas CoCl2 had no effect. Since HIF-1α induces VEGF expression, the effect of SU-5416, a potent VEGF receptor (VEGFR) blocker, on early lung development was also investigated. Inhibition of VEGFR2 signaling in explants maintained under hypoxic (2% O2) conditions completely abolished vascularization and slightly decreased epithelial branching. Taken together, the data suggest that DMOG stabilization of HIF-1α during early development leads to a hypervascular lung and that airway branching proceeds without the vasculature, albeit at a slower rate.

Glucuronyl C5-epimerase is crucial for epithelial cell maturation during embryonic lung development

Glycobiology ◽  
2020 ◽  
Author(s):  
Hao Cui ◽  
Xiaowen Cheng ◽  
Tahira Batool ◽  
Xiao Zhang ◽  
Jin-Ping Li
Keyword(s):  
Lung Development ◽  
Surfactant Protein ◽  
Branching Morphogenesis ◽  
Sulfated Polysaccharide ◽  
Alveolar Epithelial Cells ◽  
Type I ◽  
Alveolar Epithelial ◽  
Neonatal Lethality ◽  
Key Enzyme ◽  
Distal Lung

Abstract Glucuronyl C5-epimerase (Hsepi) is a key enzyme in the biosynthesis of heparan sulfate that is a sulfated polysaccharide expressed on the cell surface and in the extracellular matrix of alveolar walls and blood vessels. Targeted interruption of the Hsepi gene, Glce, in mice resulted in neonatal lethality, which is most likely due to lung atelectasis. In this study, we examined the potential mechanisms behind the defect in lung development. Histological analysis of the lungs from embryos revealed no difference in the morphology between wild-type and mutant animals up to E16.5. This suggests that the initial events leading to formation of the lung primordium and branching morphogenesis are not disturbed. However, the distal lung of E17.5–18.5 mutants is still populated by epithelial tubules, lacking the typical saccular structural characteristic of a normal E17.5 lung. Immunostaining revealed strong signals of surfactant protein-C, but a weaker signal of T1α in the mutant lungs in comparison to WT littermates, suggesting differentiation of type I alveolar epithelial cells (AT1) is impaired. One of the parameters contributed to the failure of AT1 maturation is reduced vascularization in the developing lungs.

scholarly journals Retinoic Acid: A Key Regulator of Lung Development

Biomolecules ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 152 ◽  
Author(s):  
Hugo Fernandes-Silva ◽  
Henrique Araújo-Silva ◽  
Jorge Correia-Pinto ◽  
Rute S Moura
Keyword(s):  
Retinoic Acid ◽  
Lung Development ◽  
Target Genes ◽  
Branching Morphogenesis ◽  
Developmental Pathways ◽  
Adult Tissue ◽  
Spatiotemporal Regulation ◽  
Organ Systems ◽  
Developmental Phases ◽  
Pulmonary Vascular Development

Retinoic acid (RA) is a key molecular player in embryogenesis and adult tissue homeostasis. In embryo development, RA plays a crucial role in the formation of different organ systems, namely, the respiratory system. During lung development, there is a spatiotemporal regulation of RA levels that assures the formation of a fully functional organ. RA signaling influences lung specification, branching morphogenesis, and alveolarization by regulating the expression of particular target genes. Moreover, cooperation with other developmental pathways is essential to shape lung organogenesis. This review focuses on the events regulated by retinoic acid during lung developmental phases and pulmonary vascular development; also, it aims to provide a snapshot of RA interplay with other well-known regulators of lung development.

scholarly journals Midkine Is Involved in Kidney Development and in Its Regulation by Retinoids

2002 ◽  
Vol 13 (3) ◽  
pp. 668-676
Author(s):  
José Vilar ◽  
Claude Lalou ◽  
Jean-Paul Duong Van Huyen ◽  
Stéphanie Charrin ◽  
Sylvie Hardouin ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Neutralizing Antibodies ◽  
Kidney Development ◽  
Vitamin A Deficiency ◽  
Branching Morphogenesis ◽  
Defined Medium ◽  
Dependent Manner ◽  
Heparin Binding

ABSTRACT. In the kidney, in which development depends on epithelial-mesenchymal interactions, it has been shown that retinoids modulate nephrogenesis in a dose-dependent manner in vivo and in vitro. Midkine (MK) is a retinoic acid responsive gene for a heparin-binding growth factor. The aim of the present study was therefore to quantify the expression of MK mRNA during renal development in the rat, to analyze the regulation of MK expression by retinoids in vivo and in vitro, and, finally, to study the role of MK in rat metanephric organ cultures. The spatiotemporal expression of MK in fetal kidney was studied. In control rats, MK expression is ubiquitous at gestational day 14, i.e., at the onset of nephrogenesis. On day 16, MK is expressed in the condensed mesenchyme and in early epithelialized mesenchymal derivatives. On gestational day 21, MK is rather localized in the nonmature glomeruli of the renal cortex. In utero exposure to vitamin A deficiency did not modify the specific spatial and temporal expression pattern of MK gene in the metanephros, although a decrease in mRNA expression occurred. In metanephroi explanted from 14-d-old fetuses and cultured in a defined medium, expression of MK mRNA was found to be stimulated when retinoic acid (100 nM) was added in the culture medium. Finally, in vitro nephrogenesis was strongly inhibited in the presence of neutralizing antibodies for MK: the number of nephrons formed in vitro was reduced by ∼50% without changes in ureteric bud branching morphogenesis. These results indicated that MK is implicated in the regulation of kidney development by retinoids. These results also suggested that MK plays an important role in the molecular cascade of the epithelial conversion of the metanephric blastema.

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