The Role of Ephrins-B1 and -B2 During Fetal Rat Lung Development

Abstract

Background/ Aims: The knowledge of the molecular network that governs fetal lung branching is an essential step towards the discovery of novel therapeutic targets against pulmonary pathologies. Lung consists of two highly branched systems: airways and vasculature. Ephrins and its receptors, Eph, have been implicated in cardiovascular development, angiogenesis and vascular remodeling. This study aims to clarify the role of these factors during lung morphogenesis. Methods: Ephrins-B1, -B2 and receptor EphB4 expression pattern was assessed in fetal rat lungs between 15.5 and 21.5 days post-conception, by immunohistochemistry. Fetal rat lungs were harvested at 13.5 dpc, cultured during 4 days and treated with increasing doses of ephrins-B1 and -B2 and the activity of key signaling pathways was assessed. Results: Ephrin-B1 presents mesenchymal expression, whereas ephrin-B2 and its receptor EphB4 were expressed by the epithelium. Both ephrins stimulated pulmonary branching. Moreover, while ephrin-B1 did not affect the pathways studied, ephrin-B2 supplementation decreased activity of JNK, ERK and STAT. This study characterizes the expression pattern of ephrins-B1, -B2 and EphB4 receptor throughout rat lung development. Conclusion: Our data highlight a possible role of ephrins as molecular stimulators of lung morphogenesis. Moreover, it supports the idea that classical vascular factors might play a role as airway growth promoters.

STATs in Lung Development: Distinct Early and Late Expression, Growth Modulation and Signaling Dysregulation in Congenital Diaphragmatic Hernia

“…Immunostaining was performed on paraformaldehyde-fixed and paraffin-embedded excised lungs and embryos of different gestational ages (15.5 -21.5 dpc) as previously described [26][27][28]. Primary antibodies for STAT1 (1:200, Abcam Inc., UK), STAT2 (1:50, Abcam Inc.), STAT3 (1:50, Cell Signaling Technology Inc., USA), STAT4 (1:50, Cell Signaling Technology Inc.), STAT5 (1:50, Santa Cruz Biotechnology Inc., USA), and STAT6 (1:50, Abcam Inc.) were used.…”

“…Proteins were obtained according to Kling et al [29]., and the protocol was performed as previously described [28]. , and the quantitative analysis was performed with Quantity One 4.6.5 1-D Analysis Software (Bio-Rad).…”

“…Then, the lungs were transferred to porous membranes (Isopore™ membrane filters, Merck Millipore, Germany) and cultured for 4 days as previously described [28,30]. The culture medium was replaced every 48 hours.…”

EphB4 Regulates Self-Renewal, Proliferation and Neuronal Differentiation of Human Embryonic Neural Stem Cells in Vitro

“…In mammals, there are nine EphA receptors (EphA1–8 and EphA10) and five EphB receptors (EphB1-4 and EphB6) [10]. Their ligands, the ephrins, are also subdivided into an A-subclass (ephrinA1–ephrinA5), which are tethered to the exoplasmic leaflet of the cell membrane by a glycosylphosphatidylinositol (GPI) anchor, and the B-subclass (ephrinB1–ephrinB3), which contain transmembrane and cytoplasmic regions [11, 12]. Ephrins and Eph receptors have been implicated in the control of neural stem cell proliferation, survival and differentiation.…”

Developmental Origins of Disease - Crisis Precipitates Change

“…There is an increasing body of evidence that prematurity is associated with an increased risk for various disease in adult life [53,87,[89][90][91]. It is known that preterm birth causes an interruption of normal organogenesis, especially in organ systems that display a branching morphogenesis like kidney, lung, pancreas, and the vascular system [87,[92][93][94]. The developing kidney is particularly vulnerable to preterm birth which causes considerable deficits in organ structure and function [93].…”