Conditional deletion of Abca3 in alveolar type II cells alters surfactant homeostasis in newborn and adult mice

Am J Physiol Lung Cell Mol Physiol. 2010 May;298(5):L646-59. doi: 10.1152/ajplung.00409.2009. Epub 2010 Feb 26.

Abstract

ATP-binding cassette A3 (ABCA3) is a lipid transport protein required for synthesis and storage of pulmonary surfactant in type II cells in the alveoli. Abca3 was conditionally deleted in respiratory epithelial cells (Abca3(Δ/Δ)) in vivo. The majority of mice in which Abca3 was deleted in alveolar type II cells died shortly after birth from respiratory distress related to surfactant deficiency. Approximately 30% of the Abca3(Δ/Δ) mice survived after birth. Surviving Abca3(Δ/Δ) mice developed emphysema in the absence of significant pulmonary inflammation. Staining of lung tissue and mRNA isolated from alveolar type II cells demonstrated that ∼50% of alveolar type II cells lacked ABCA3. Phospholipid content and composition were altered in lung tissue, lamellar bodies, and bronchoalveolar lavage fluid from adult Abca3(Δ/Δ) mice. In adult Abca3(Δ/Δ) mice, cells lacking ABCA3 had decreased expression of mRNAs associated with lipid synthesis and transport. FOXA2 and CCAAT enhancer-binding protein-α, transcription factors known to regulate genes regulating lung lipid metabolism, were markedly decreased in cells lacking ABCA3. Deletion of Abca3 disrupted surfactant lipid synthesis in a cell-autonomous manner. Compensatory surfactant synthesis was initiated in ABCA3-sufficient type II cells, indicating that surfactant homeostasis is a highly regulated process that includes sensing and coregulation among alveolar type II cells.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • ATP-Binding Cassette Transporters / antagonists & inhibitors*
  • ATP-Binding Cassette Transporters / genetics*
  • ATP-Binding Cassette Transporters / metabolism
  • Alveolar Epithelial Cells / metabolism*
  • Alveolar Epithelial Cells / ultrastructure
  • Animals
  • Animals, Newborn
  • Base Sequence
  • Disease Models, Animal
  • Female
  • Gene Expression
  • Homeostasis
  • Humans
  • Infant, Newborn
  • Lipid Metabolism
  • Mice
  • Microscopy, Electron, Transmission
  • Pregnancy
  • Pulmonary Emphysema / etiology
  • Pulmonary Emphysema / genetics
  • Pulmonary Emphysema / metabolism
  • Pulmonary Emphysema / pathology
  • Pulmonary Surfactant-Associated Proteins / deficiency
  • Pulmonary Surfactant-Associated Proteins / metabolism*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Respiratory Distress Syndrome, Newborn / etiology

Substances

  • ATP-Binding Cassette Transporters
  • Abca3 protein, mouse
  • Pulmonary Surfactant-Associated Proteins
  • RNA, Messenger