Developmental Expression and Glucocorticoid Control of the Leptin Receptor in Fetal Ovine Lung

PLoS One. 2015 Aug 19;10(8):e0136115. doi: 10.1371/journal.pone.0136115. eCollection 2015.

Abstract

The effects of endogenous and synthetic glucocorticoids on fetal lung maturation are well-established, although the role of leptin in lung development before birth is unclear. This study examined mRNA and protein levels of the signalling long-form leptin receptor (Ob-Rb) in fetal ovine lungs towards term, and after experimental manipulation of glucocorticoid levels in utero by fetal cortisol infusion or maternal dexamethasone treatment. In fetal ovine lungs, Ob-Rb protein was localised to bronchiolar epithelium, bronchial cartilage, vascular endothelium, alveolar macrophages and type II pneumocytes. Pulmonary Ob-Rb mRNA abundance increased between 100 (0.69 fractional gestational age) and 144 days (0.99) of gestation, and by 2-4-fold in response to fetal cortisol infusion and maternal dexamethasone treatment. In contrast, pulmonary Ob-Rb protein levels decreased near term and were halved by glucocorticoid treatment, without any significant change in phosphorylated signal transducer and activator of transcription-3 (pSTAT3) at Ser727, total STAT3 or the pulmonary pSTAT3:STAT3 ratio. Leptin mRNA was undetectable in fetal ovine lungs at the gestational ages studied. These findings demonstrate differential control of pulmonary Ob-Rb transcript abundance and protein translation, and/or post-translational processing, by glucocorticoids in utero. Localisation of Ob-Rb in the fetal ovine lungs, including alveolar type II pneumocytes, suggests a role for leptin signalling in the control of lung growth and maturation before birth.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alveolar Epithelial Cells / metabolism
  • Animals
  • Dexamethasone / pharmacology
  • Female
  • Fetus / metabolism
  • Gene Expression Regulation, Developmental / drug effects
  • Glucocorticoids / pharmacology
  • Hydrocortisone / blood
  • Hydrocortisone / pharmacology
  • Lung / drug effects
  • Lung / embryology*
  • Lung / metabolism*
  • Phosphorylation
  • Pregnancy
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptors, Leptin / genetics*
  • Receptors, Leptin / metabolism*
  • STAT3 Transcription Factor / chemistry
  • STAT3 Transcription Factor / metabolism
  • Sheep, Domestic
  • Signal Transduction

Substances

  • Glucocorticoids
  • RNA, Messenger
  • Receptors, Leptin
  • STAT3 Transcription Factor
  • Dexamethasone
  • Hydrocortisone