Eur J Pediatr Surg 2018; 28(01): 109-114
DOI: 10.1055/s-0037-1604022
Original Article
Georg Thieme Verlag KG Stuttgart · New York

Decreased Expression of Integrin Subunits α3, α6, and α8 in the Branching Airway Mesenchyme of Nitrofen-Induced Hypoplastic Lungs

Toshiaki Takahashi
1  National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
,
Florian Friedmacher
1  National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
,
Julia Zimmer
1  National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
2  Department of Pediatric Surgery, Medizinische Hochschule Hannover Zentrum Chirurgie, Hannover, Germany
,
Prem Puri
1  National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
› Author Affiliations
Further Information

Publication History

19 April 2017

23 May 2017

Publication Date:
12 July 2017 (eFirst)

Abstract

Introduction Pulmonary hypoplasia (PH), characterized by smaller lung size and reduced airway branching, remains a major cause of neonatal mortality in newborns with congenital diaphragmatic hernia (CDH). Integrin-mediated cell–matrix interactions play an essential role in the fetal lung mesenchyme by stimulating branching morphogenesis. Mice lacking integrin subunits α3 (Itga3) and α6 (Itga6) exhibit severe PH. Furthermore, Itga8-knockout mice show defective airway branching, suggesting that Itga3, Itga6, and Itga8 are crucial for fetal lung development. We hypothesized that expression of Itga3, Itga6, and Itga8 is decreased in the branching airway mesenchyme of hypoplastic rat lungs in the nitrofen-induced CDH model.

Materials and Methods Time-mated rats received nitrofen or vehicle on gestational day 9 (D9). Fetuses were sacrificed on D15, D18, and D21, and dissected lungs were divided into control and nitrofen-exposed specimens (n = 12 per time-point and group, respectively). Pulmonary gene expression of Itga3, Itga6, and Itga8 was analyzed by quantitative real-time polymerase chain reaction. Immunofluorescence double-staining for Itga3, Itga6, and Itga8 was combined with the mesenchymal marker Fgf10 to evaluate protein expression and localization in branching airway tissue.

Results Relative mRNA expression of Itga3, Itga6, and Itga8 was significantly decreased in lungs of nitrofen-exposed fetuses on D15, D18, and D21 compared with controls. Confocal laser scanning microscopy showed markedly diminished immunofluorescence of Itga3, Itga6, and Itga8 mainly in mesenchymal cells surrounding branching airways of nitrofen-exposed fetuses on D15, D18, and D21 compared with controls.

Conclusion Decreased expression of Itga3, Itga6, and Itga8 in the pulmonary mesenchyme may lead to disruptions in airway branching morphogenesis, thus contributing to PH in the nitrofen-induced CDH model.