27 research outputs found
Steroid and Oxygen Effects on eIF4F Complex, mTOR, and ENaC Translation in Fetal Lung Epithelia
Oxygen and Glucocorticoids Modulate αENaC mRNA Translation in Fetal Distal Lung Epithelium
Expression of epithelial sodium channel α-subunit mRNAs with alternative 5′-untranslated regions in the developing human lung
The role of α-, β-, and γ-ENaC subunits in distal lung epithelial fluid absorption induced by pulmonary edema fluid
Bradykinin Production and Increased Pulmonary Endothelial Permeability during Acute Respiratory Failure in Unanesthetized Sheep
Pulmonary oedema fluid induces non-α-ENaC-dependent Na+ transport and fluid absorption in the distal lung
To determine if pulmonary oedema fluid (EF) alters ion and fluid transport of distal lung epithelium (DLE), EF was collected from rats in acute heart failure. EF, but not plasma, increased amiloride-insensitive short circuit current (Isc) and Na+–K+ ATPase protein content and pump activity of DLE grown in primary culture. Inhibitors of Cl− transport or cGMP-gated cation channels had a significant (P < 0.05), but limited ability to block the increased Isc. EF increased amiloride-insensitive, but not amiloride-sensitive, DLE apical membrane Na+ conductance. The level of mRNA encoding epithelial sodium channel (ENaC) subunits was unchanged (α, β), or decreased (γ, P < 0.05) in EF-exposed DLE. EF also induced an amiloride-insensitive increase in the potential difference across murine tracheal cysts. Distal lung explants from late gestation wild-type and α-ENaC-deficient fetal mice, which normally expand due to liquid secretion, decreased in size due to liquid absorption when exposed to EF. Trypsin digestion or heat treatment of EF abrogated the ability of EF to increase amiloride-insensitive Isc in DLE and liquid absorption by distal lung explants. Thus proteins or protein-dependent factors within cardiogenic EF induce an α-ENaC-independent and amiloride-insensitive apical membrane Na+ conductance and liquid absorption in the distal lung