title: Follistatin-like 1 expression is decreased in the alveolar epithelium of hypoplastic rat lungs with nitrofen-induced congenital diaphragmatic hernia.
abstract: OBJECTIVE
  Pulmonary hypoplasia (PH), characterized by incomplete alveolar development, remains a major therapeutic challenge associated with congenital diaphragmatic hernia (CDH). Follistatin-like 1 (Fstl1) is a crucial regulator of alveolar formation and maturation, which is strongly expressed in distal airway epithelium. Fstl1-deficient mice exhibit reduced airspaces, impaired alveolar epithelial cell differentiation, and insufficient production of surfactant proteins similar to PH in human CDH. We hypothesized that pulmonary Fstl1 expression is decreased during alveolarization in the nitrofen-induced CDH model.
  
  
  METHODS
  Timed-pregnant rats received nitrofen or vehicle on gestational day 9 (D9). Fetal lungs were harvested on D18 and D21 and divided into control-/nitrofen-exposed specimens. Alveolarization was assessed using morphometric analysis techniques. Pulmonary gene expression of Fstl1 was determined by qRT-PCR. Immunofluorescence-double-staining for Fstl1 and alveolar epithelial marker surfactant protein C (SP-C) was performed to evaluate protein expression/localization.
  
  
  RESULTS
  Radial alveolar count was significantly reduced in hypoplastic lungs of nitrofen-exposed fetuses with significant down regulation of Fstl1 mRNA expression on D18 and D21 compared to controls. Confocal-laser-scanning-microscopy revealed strikingly diminished Fstl1 immunofluorescence and SP-C expression in distal alveolar epithelium of nitrofen-exposed fetuses with CDH-associated PH on D18 and D21 compared to controls.
  
  
  CONCLUSIONS
  Decreased expression of Fstl1 in alveolar epithelium may disrupt alveolarization and pulmonary surfactant production, thus contributing to the development of PH in the nitrofen-induced CDH model.
  
  
  METHODS
  2b (Centre for Evidence-Based Medicine, Oxford).
authors.affiliation: National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Gate 5, Dublin 12, Dublin, Ireland.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Gate 5, Dublin 12, Dublin, Ireland.
authors.forename: Julia
authors.initials: J
authors.lastname: Zimmer
authors.affiliation: National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Gate 5, Dublin 12, Dublin, Ireland.
authors.forename: Florian
authors.initials: F
authors.lastname: Friedmacher
authors.affiliation: National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Gate 5, Dublin 12, Dublin, Ireland; Conway Institute of Biomolecular and Biomedical Research, School of Medicine & Medical Science, University College Dublin, Belfield, Dublin, 4, Dublin, Ireland. Electronic address: prem.puri@ncrc.ie.
authors.forename: Prem
authors.initials: P
authors.lastname: Puri
mesh_terms: D000015:Abnormalities, Multiple / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D015536:Down-Regulation; D005455:Fluorescent Antibody Technique; D038702:Follistatin-Related Proteins / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D065630:Hernias, Diaphragmatic, Congenital / Q000139:chemically induced / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D008168:Lung / Q000002:abnormalities* / Q000196:embryology / Q000378:metabolism; D008171:Lung Diseases / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D010647:Phenyl Ethers; D011650:Pulmonary Alveoli / Q000196:embryology / Q000378:metabolism*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D020545:Respiratory Mucosa / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D038702:Follistatin-Related Proteins; D010647:Phenyl Ethers; C448719:Fstl1 protein, rat; C007350:nitrofen
keywords: Congenital diaphragmatic hernia; Follistatin-like 1; Lung alveolarization; Nitrofen; Pulmonary hypoplasia; Pulmonary surfactant protein