Transcriptional regulation of the surfactant protein-A gene in fetal lung

From the pathophysiology of the human lung alveolus to epigenetic editing: Congress 2018 highlights from ERS Assembly 3 "Basic and Translational Science."

The European Respiratory Society (ERS) International Congress is the largest respiratory congress and brings together leading experts in all fields of respiratory medicine and research. ERS Assembly 3 shapes the basic and translational science aspects of this congress, aiming to combine cutting-edge novel developments in basic research with novel clinical findings. In this article, we summarise a selection of the scientific highlights from the perspective of the three groups within Assembly 3. In particular, we discuss new insights into the pathophysiology of the human alveolus, novel tools in organoid development and (epi)genome editing, as well as insights from the presented abstracts on novel therapeutic targets being identified for idiopathic pulmonary fibrosis.

The amount of basic and translational science presented at #ERSCongress is steadily increasing, showing novel cutting-edge technologies and models.http://bit.ly/2GgXIJi

Human lung development: recent progress and new challenges

Recent studies have revealed biologically significant differences between human and mouse lung development, and have reported new in vitro systems that allow experimental manipulation of human lung models. At the same time, emerging clinical data suggest that the origins of some adult lung diseases are found in embryonic development and childhood. The convergence of these research themes has fuelled a resurgence of interest in human lung developmental biology. In this Review, we discuss our current understanding of human lung development, which has been profoundly influenced by studies in mice and, more recently, by experiments using in vitro human lung developmental models and RNA sequencing of human foetal lung tissue. Together, these approaches are helping to shed light on the mechanisms underlying human lung development and disease, and may help pave the way for new therapies.

Summary: This Review describes how recent technological advances have shed light on the mechanisms underlying human lung development and disease, and outlines the future challenges in this field.

Foxp4: a novel member of the Foxp subfamily of winged-helix genes co-expressed with Foxp1 and Foxp2 in pulmonary and gut tissues

In this study, we describe the isolation and characterization of Foxp4, a new member of the Foxp subfamily of winged-helix transcription factors. The full-length mouse Foxp4 cDNA encodes a 685-amino-acid protein that is similar to Foxp1 and Foxp2. Foxp4 gene expression is observed primarily in pulmonary, neural, and gut tissues during embryonic development. To compare the protein expression patterns of Foxp4 to Foxp1 and Foxp2, specific polyclonal antisera to each of these proteins was used in immunohistochemical analysis of mouse embryonic tissues. All three proteins are expressed in lung epithelium with Foxp1 and Foxp4 expressed in both proximal and distal airway epithelium while Foxp2 is expressed primarily in distal epithelium. Foxp1 protein expression is also observed in the mesenchyme and vascular endothelial cells of the lung. At embryonic day 12.5, Foxp1 and Foxp2 are expressed in both the mucosal and epithelial layers of the intestine. However, Foxp2 is expressed only in the outer mucosal layer of the intestine and stomach later in development. Finally, Foxp4 is expressed exclusively in the epithelial cells of the developing intestine, where, in late development, it is expressed in a gradient along the longitudinal axis of the villi.

Glucocorticoids and the Lung

The lung is a major clinical target of glucocorticoid-based therapeutics, and GR signaling has broad effects on respiratory physiology and inflammation. During lung development, expression of GR in the mesenchyme is required for normal terminal alveolar epithelial differentiation. Prenatal administration of exogenous glucocorticoids (GCs) to prevent neonatal respiratory distress syndrome, however, promotes alveolar maturation and accelerates surfactant expression in a manner consistent with direct effects on the developing alveolar epithelium. Likewise, cell autonomous effects of GCs in regulating gene expression and phenotype of the airway epithelium and airway smooth muscle have been demonstrated to control important therapeutic effects of GCs in treating asthma and chronic obstructive pulmonary disease. Here, mechanisms and consequences of GR signaling in the developing lung and in treating obstructive lung disease are reviewed, with a focus on direct effects of GR signaling on alveolar differentiation, surfactant expression, and airway epithelial and smooth muscle pathophysiology.