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

V Besnard, Y Matsuzaki, J Clark, Y Xu… - … of Physiology-Lung …, 2010 - journals.physiology.org
V Besnard, Y Matsuzaki, J Clark, Y Xu, SE Wert, M Ikegami, MT Stahlman, TE Weaver…
American Journal of Physiology-Lung Cellular and Molecular …, 2010journals.physiology.org
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 …
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 (Abca3Δ/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 Abca3Δ/Δ mice survived after birth. Surviving Abca3Δ/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 Abca3Δ/Δ mice. In adult Abca3Δ/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.
American Physiological Society