Damage to alveoli, the gas-exchanging region of the lungs, is a component of many chronic and acute lung diseases. In addition, insufficient generation of alveoli results in bronchopulmonary ...dysplasia, a disease of prematurity. Therefore visualising the process of alveolar development (alveologenesis) is critical for our understanding of lung homeostasis and for the development of treatments to repair and regenerate lung tissue. Here we show live alveologenesis, using long-term, time-lapse imaging of precision-cut lung slices. We reveal that during this process, epithelial cells are highly mobile and we identify specific cell behaviours that contribute to alveologenesis: cell clustering, hollowing and cell extension. Using the cytoskeleton inhibitors blebbistatin and cytochalasin D, we show that cell migration is a key driver of alveologenesis. This study reveals important novel information about lung biology and provides a new system in which to manipulate alveologenesis genetically and pharmacologically.
Planar cell polarity in organ formation Henderson, Deborah J; Long, David A; Dean, Charlotte H
Current opinion in cell biology,
December 2018, 2018-12-00, 20181201, Letnik:
55
Journal Article
Recenzirano
Odprti dostop
The planar cell polarity (PCP) pathway controls a variety of morphological events across many species. During embryonic development, the PCP pathway regulates coordinated behaviour of groups of cells ...to direct morphogenetic processes such as convergent extension and collective cell migration. In this review we discuss the increasingly prominent role of the PCP pathway in organogenesis, focusing on the lungs, kidneys and heart. We also highlight emerging evidence that PCP gene mutations are associated with adult diseases.
Simple Models of Lung Development Dean, Charlotte H; Cheong, Sek-Shir
Advances in experimental medicine and biology,
2023, Letnik:
1413
Journal Article
Recenzirano
Models are essential to further our understanding of lung development and regeneration and to facilitate identification and testing of potential treatments for lung diseases. A wide variety of rodent ...and human models are available that recapitulate one or more stages of lung development. This chapter describes the existing 'simple' in vitro, in silico and ex vivo models of lung development. We define which stage(s) of development each model recapitulates and highlight their pros and cons.
Abstract Background Genome-wide association studies have identified the ORMDL3 (ORM (yeast)-like protein isoform 3) gene locus on human chromosome 17q to be a highly significant risk factor for ...childhood-onset asthma. Objective We sought to investigate in vivo the functional role of ORMDL3 in disease inception. Methods An Ormdl3 deficient mouse was generated and the role of ORMDL3 in the generation of allergic airways disease to the fungal aeroallergen Alternaria alternata determined. An adeno-associated viral vector was also utilized to reconstitute ORMDL3 expression in airway epithelial cells of Ormdl3 KO mice. Results Ormdl3 knock-out mice were found to be protected from developing allergic airways disease and showed a marked decrease in pathophysiology, including lung function and airway eosinophilia induced by Alternaria. Alternaria is a potent inducer of cellular stress and the unfolded protein response and ORMDL3 was found to play a critical role in driving the ATF6 mediated arm of this response through Xbp1 and downstream activation of the endoplasmic reticulum-associated degradation pathway. Additionally ORMDL3 mediated uric acid release, another marker of cellular stress. In the knockout mice, reconstitution of Ormdl3 transcript levels specifically in the bronchial epithelium resulted in reinstatement of susceptibility to fungal allergen-induced allergic airways disease. Conclusions This study demonstrates that ORMDL3 , an asthma susceptibility gene identified by genome-wide association studies, contributes to key pathways that promote changes in airway physiology during allergic immune responses.
Precision-cut lung slices (PCLS) are used for a variety of applications. However, methods to manipulate genes in PCLS are currently limited. We developed a new method, TAT-Cre recombinase-mediated ...floxed allele modification in tissue slices (TReATS), to induce highly effective and temporally controlled gene deletion or activation in ex vivo PCLS. Treatment of PCLS from Rosa26-flox-stop-flox-EYFP mice with cell-permeant TAT-Cre recombinase induced ubiquitous EYFP protein expression, indicating successful Cre-mediated excision of the upstream loxP-flanked stop sequence. Quantitative real-time PCR confirmed induction of EYFP. We successfully replicated the TReATS method in PCLS from Vangl2flox/flox mice, leading to the deletion of loxP-flanked exon 4 of the Vangl2 gene. Cre-treated Vangl2flox/flox PCLS exhibited cytoskeletal abnormalities, a known phenotype caused by VANGL2 dysfunction. We report a new method that bypasses conventional Cre-Lox breeding, allowing rapid and highly effective gene manipulation in ex vivo tissue models.
Congenital pulmonary airway malformations (CPAMs) are rare lung abnormalities that result in cyst formation and are associated with respiratory distress in infants and malignant potential in adults. ...The pathogenesis of CPAMs remains unknown but data suggest disruption of the normal proximo-distal programme of airway branching and differentiation. Here, we demonstrate that adult human CPAM are lined with epithelium that retains SOX-2 and thyroid transcription factor-1 immunohistochemical markers, characteristic of the developing lung. However, RALDH-1, another key marker, is absent. This suggests a more complex aetiology for CPAM than complete focal arrest of lung development and may provide insight to the associated risk of malignancy.
The extracellular matrix (ECM) is not just a three-dimensional scaffold that provides stable support for all cells in the lungs, but also an important component of chronic fibrotic airway, vascular, ...and interstitial diseases. It is a bioactive entity that is dynamically modulated during tissue homeostasis and disease, that controls structural and immune cell functions and drug responses, and that can release fragments that have biological activity and that can be used to monitor disease activity. There is a growing recognition of the importance of considering ECM changes in chronic airway, vascular, and interstitial diseases, including
) compositional changes,
) structural and organizational changes, and
) mechanical changes and how these affect disease pathogenesis. As altered ECM biology is an important component of many lung diseases, disease models must incorporate this factor to fully recapitulate disease-driver pathways and to study potential novel therapeutic interventions. Although novel models are evolving that capture some or all of the elements of the altered ECM microenvironment in lung diseases, opportunities exist to more fully understand cell-ECM interactions that will help devise future therapeutic targets to restore function in chronic lung diseases. In this perspective article, we review evolving knowledge about the ECM's role in homeostasis and disease in the lung.
During development, intestinal epithelia undergo dramatic morphogenesis mediated by mesenchymal signaling to form villi, which are required for efficient nutrient absorption and host defense. ...Although both smooth-muscle-induced physical forces and mesenchymal cell clustering beneath emerging villi are implicated in epithelial folding, the underlying cellular mechanisms are unclear. Hedgehog (Hh) signaling can mediate both processes. We therefore analyzed its direct targetome and revealed GLI2 transcriptional activation of atypical cadherin and planar cell polarity (PCP) genes. By examining Fat4 and Dchs1 knockout mice, we demonstrate their critical roles in villus formation. Analyses of PCP-mutant mice and genetic interaction studies show that the Fat4-Dchs1 axis acts in parallel to the core-Vangl2 PCP axis to control mesenchymal cell clustering. Moreover, live light-sheet fluorescence microscopy and cultured PDGFRα+ cells reveal a requirement for PCP in their oriented cell migration guided by WNT5A. Therefore, mesenchymal PCP induced by Hh signaling drives cell clustering and subsequent epithelial remodeling.
Display omitted
•Hh activates planar cell polarity genes in the developing intestinal mesenchyme•Fat4 pathway is required for proper mesenchymal clustering in villus formation•Planar cell polarity mechanisms ensure organized stromal cell behavior•Stromal clustering through planar polarity is required for villus demarcation
Rao-Bhatia et al. investigate the signaling mechanisms of cell behavior during mammalian villus morphogenesis. They demonstrate that Hh signaling in the intestinal mesenchyme directly activates planar cell polarity genes, thereby regulating the stromal cell clustering behavior required for epithelial remodeling in villus formation.
PDF
