Differentiation of type II cells of human fetal lung in vitro.
Lung tissue explants from mid-trimester human abortuses were maintained for 8 days in organ culture in medium with or without serum. Before the start of culture the cells lining the pre-alveolar ducts were undifferentiated and contained no lamellar bodies, the intracellular organelle that contains surfactant. After 4 days in organ culture, the epithelium lining the pre-alveolar ducts was composed of differentiated type II cells containing numerous lamellar bodies. During the 8-day culture period there was increased incorporation of [3H]choline into phosphatidylcholine and disaturated phosphatidylcholine. In addition, the specific activity of phosphatidate phosphohydrolase, a regulatory enzyme in lung phospholipid synthesis, increased 4-fold during the culture period. Lamellar bodies isolated by differential centrifugation from explants maintained in culture for 7 days had the characteristic ultrastructure described for this organelle. Lamellar bodies were isolated from explants which had been incubated with [14C]glycerol. When the glycerophospholipid composition of lamellar bodies was analyzed it was found that the majority of the radiolabeled glycerol (74%) was incorporated into phosphatidylcholine and into the anionic phospholipids, phosphatidylglycerol (5%) and phosphatidylinositol (6%). Thus, human fetal lung explants maintained in organ culture contain differentiated type II cells which synthesize surfactant characteristic of human fetal lung at 36 to 38 weeks of gestation.
D002454:Cell Differentiation; D002794:Choline / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D008168:Lung / Q000166:cytology* / Q000196:embryology / Q000378:metabolism; D009924:Organ Culture Techniques; D009940:Organoids / Q000648:ultrastructure; D010711:Phosphatidate Phosphatase / Q000378:metabolism; D010713:Phosphatidylcholines / Q000096:biosynthesis; D010743:Phospholipids / Q000096:biosynthesis
D010713:Phosphatidylcholines; D010743:Phospholipids; D010711:Phosphatidate Phosphatase; D002794:Choline; D005990:Glycerol