Normalisation of surfactant protein -A and -B expression in the lungs of low birth weight lambs by 21 days old

PLoS One. 2017 Sep 26;12(9):e0181185. doi: 10.1371/journal.pone.0181185. eCollection 2017.

Abstract

Intrauterine growth restriction (IUGR) induced by placental restriction (PR) in the sheep negatively impacts lung and pulmonary surfactant development during fetal life. Using a sheep model of low birth weight (LBW), we found that there was an increase in mRNA expression of surfactant protein (SP)-A, -B and -C in the lung of LBW lambs but no difference in the protein expression of SP-A or -B. LBW also resulted in increased lysosome-associated membrane glycoprotein (LAMP)-3 mRNA expression, which may indicate an increase in either the density of type II Alveolar epithelial cells (AEC) or maturity of type II AECs. Although there was an increase in glucocorticoid receptor (GR) and 11β-hydroxysteroid dehydrogenase (11βHSD)-1 mRNA expression in the lung of LBW lambs, we found no change in the protein expression of these factors, suggesting that the increase in SP mRNA expression is not mediated by increased GC signalling in the lung. The increase in SP mRNA expression may, in part, be mediated by persistent alterations in hypoxia signalling as there was an increase in lung HIF-2α mRNA expression in the LBW lamb. The changes in the hypoxia signalling pathway that persist within the lung after birth may be involved in maintaining SP production in the LBW lamb.

MeSH terms

  • 11-beta-Hydroxysteroid Dehydrogenases / genetics
  • 11-beta-Hydroxysteroid Dehydrogenases / metabolism
  • Animals
  • Body Weight
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Infant, Low Birth Weight*
  • Lung / metabolism*
  • Lysosomal Membrane Proteins / genetics
  • Lysosomal Membrane Proteins / metabolism
  • Organ Size
  • Pulmonary Surfactant-Associated Protein A / genetics
  • Pulmonary Surfactant-Associated Protein A / metabolism*
  • Pulmonary Surfactant-Associated Protein B / genetics
  • Pulmonary Surfactant-Associated Protein B / metabolism*
  • RNA, Messenger / genetics
  • Real-Time Polymerase Chain Reaction
  • Sheep

Substances

  • Lysosomal Membrane Proteins
  • Pulmonary Surfactant-Associated Protein A
  • Pulmonary Surfactant-Associated Protein B
  • RNA, Messenger
  • 11-beta-Hydroxysteroid Dehydrogenases

Grants and funding

The animal component of the work was funded by a National Health and Medical Research Council Program Grant (https://www.nhmrc.gov.au/grants-funding/apply-funding/program-grants) (ICM). The molecular component of the work was funded by a South Australian Cardiovascular Research Network Fellowship (https://www.heartfoundation.org.au/research/research-networks/south-australian-cardiovascular-research-network) (CR10A4988; JLM) and a National Health and Medical Research Council Project Grant (https://www.nhmrc.gov.au/grants-funding/apply-funding/program-grants) (APP1030853; JLM and SO). JLM was funded by a South Australian Cardiovascular Research Network Fellowship (https://www.heartfoundation.org.au/research/research-networks/south-australian-cardiovascular-research-network) (CR10A4988) and a National Health and Medical Research Council Career Development Fellowship (https://www.nhmrc.gov.au/grants-funding/apply-funding/career-development-fellowships) (APP1066916). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of this manuscript.