RNA interference for alpha-ENaC inhibits rat lung fluid absorption in vivo.
Absorption/drug effects; Adrenergic beta-Agonists/pharmacology; Amiloride/pharmacology; Animals; Body Fluids/*metabolism; Capillary Permeability; Dose-Response Relationship; Drug; Endothelium; Epithelial Cells/metabolism; Epithelial Sodium Channels; Epithelium/metabolism; Inhibitory Concentration 50; Lung/enzymology/*metabolism; Male; Messenger/antagonists & inhibitors/metabolism; Permeability; Plasmids/administration & dosage/pharmacology; Rats; RNA; Small Interfering/genetics/pharmacology; Sodium Channels/drug effects/genetics/metabolism/*physiology; Sprague-Dawley; Terbutaline/pharmacology; Tissue Distribution; Vascular/metabolism
We used siRNA against the alpha-ENaC (epithelial Na channel) subunit to investigate ENaC involvement in lung fluid absorption in rats by the impermeable tracer technique during baseline and after beta-adrenoceptor stimulation by terbutaline. Terbutaline stimulation of lung fluid absorption increased fluid absorption by 165% in pSi-0-pretreated rat lungs (irrelevant siRNA-generating plasmid). Terbutaline failed to increase lung fluid absorption in rats given the specific alpha-ENaC siRNA-generating plasmid (pSi-4). pSi-4 pretreatment reduced baseline lung fluid absorption by approximately 30%. alpha-ENaC was undetectable in pSi-4-pretreated lungs, regardless of condition but was normal in pSi-0-pretreated lungs. We carried out a dose-response analysis where rats were given 0-200 microg/kg body wt pSi-4, and alpha-ENaC mRNA and protein expressions were analyzed. To reach IC(50) for alpha-ENaC mRNA expression, 32 microg/kg body wt pSi-4 was needed, and to reach IC(50) for alpha-ENaC protein expression, 59 microg/kg body wt pSi-4 was needed. We tested for lung tissue specificity and found no changes in beta-ENaC expression, at either mRNA or protein level, as well as no changes in alpha(1)-Na-K-ATPase protein expression. We isolated alveolar epithelial type II cells 24 h after in vivo pSi-4 pretreatment. In these cells, alpha-ENaC mRNA was undetectable, demonstrating that alveolar epithelial ENaC expression was attenuated after intratracheal alpha-ENaC siRNA-generating plasmid DNA instillation. We tested for organ specificity and found no changes in kidney alpha- and beta-ENaC mRNA and protein expression. Thus we provide conclusive evidence that beta-adrenoceptor stimulation of lung fluid absorption is critically ENaC dependent, whereas baseline lung fluid absorption seemed less ENaC dependent.
Li Tianbo; Folkesson Hans G
American journal of physiology. Lung cellular and molecular physiology
2006
2006-04
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajplung.00205.2005" target="_blank" rel="noreferrer noopener">10.1152/ajplung.00205.2005</a>
Oxytocin-induced labor augments IL-1beta-stimulated lung fluid absorption in fetal guinea pig lungs.
*Labor; Absorption/drug effects; Amiloride/administration & dosage; Animals; Enzyme Activation/drug effects; Enzyme Inhibitors/administration & dosage; Epinephrine/metabolism; Extravascular Lung Water/*metabolism; Female; Fetal Organ Maturity/drug effects; Fetus/metabolism; Guinea Pigs; Hydrocortisone/metabolism; Induced; Interleukin-1/*administration & dosage/metabolism; Ion Transport/drug effects; Lung/*embryology; Maternal-Fetal Exchange/drug effects; Metyrapone/administration & dosage; Oxytocics/*administration & dosage; Oxytocin/*administration & dosage; Pregnancy; Propranolol/administration & dosage; Sodium Channel Blockers/administration & dosage; Sodium-Potassium-Chloride Symporters/metabolism; Vasodilator Agents/administration & dosage
We tested the hypothesis that oxytocin-induced labor augmented
Nair Prem K; Li Tianbo; Bhattacharjee Reshma; Ye Xin; Folkesson Hans G
American journal of physiology. Lung cellular and molecular physiology
2005
2005-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajplung.00256.2004" target="_blank" rel="noreferrer noopener">10.1152/ajplung.00256.2004</a>
IL-1beta-induced cortisol stimulates lung fluid absorption in fetal guinea pigs via SGK-mediated Nedd4-2 inhibition.
Absorption/drug effects; Animals; Base Sequence; Body Fluids/metabolism; DNA/genetics; Endosomal Sorting Complexes Required for Transport; Epithelial Sodium Channels/metabolism; Female; Guinea Pigs; Hydrocortisone/*biosynthesis/blood/physiology; Immediate-Early Proteins/genetics/*metabolism; Interleukin-1beta/*pharmacology; Lung/*drug effects/*physiology; Molecular Sequence Data; Nedd4 Ubiquitin Protein Ligases; Pregnancy; Protein-Serine-Threonine Kinases/genetics/*metabolism; Recombinant Proteins/pharmacology; Ubiquitin-Protein Ligases/*antagonists & inhibitors/genetics
We tested the hypothesis that interleukin (IL)-1beta-induced cortisol synthesis stimulates distal lung fluid absorption in fetal guinea pigs via induction of serum- and glucocorticoid-regulated kinase (SGK) and inhibition of neural precursor cell expressed, developmentally downregulated protein 4-2 (Nedd4-2).
Li Tianbo; Koshy Shyny; Folkesson Hans G
American journal of physiology. Lung cellular and molecular physiology
2009
2009-03
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajplung.90506.2008" target="_blank" rel="noreferrer noopener">10.1152/ajplung.90506.2008</a>
Stimulation of MAP kinase pathways after maternal IL-1beta exposure induces fetal lung fluid absorption in guinea pigs.
Absorption/drug effects; Animal/*metabolism; Animals; Body Fluids/*metabolism; Extracellular Signal-Regulated MAP Kinases/metabolism; Female; Fetus/metabolism; Gestational Age; Guinea Pigs; Hydrocortisone/*metabolism; Injections; Interleukin-1beta/administration & dosage/*pharmacology; Lung/*embryology; Mitogen-Activated Protein Kinase Kinases/metabolism; Mitogen-Activated Protein Kinases/*metabolism; Pregnancy; Rats; Recombinant Proteins/administration & dosage/pharmacology; Subcutaneous
BACKGROUND: We tested the hypothesis that maternal interleukin-1beta (IL-1beta) pretreatment and induction of fetal cortisol synthesis activates MAP kinases and thereby affects lung fluid absorption in preterm guinea pigs. METHODS: IL-1beta was administered subcutaneously daily to timed-pregnant guinea pigs for three days. Fetuses were obtained by abdominal hysterotomy and instilled with isosmolar 5% albumin into the lungs and lung fluid movement was measured over 1 h by mass balance. MAP kinase expression was measured by western blot. RESULTS: Lung fluid absorption was induced at 61 days (D) gestation and stimulated at 68D gestation by IL-1beta. Maternal IL-1beta pretreatment upregulated ERK and upstream MEK expression at both 61 and 68D gestation, albeit being much more pronounced at 61D gestation. U0126 instillation completely blocked IL-1beta-induced lung fluid absorption as well as IL-1beta-induced/stimulated ERK expression. Cortisol synthesis inhibition by metyrapone attenuated ERK expression and lung fluid absorption in IL-1beta-pretreated fetal lungs. JNK expression after maternal
Bhattacharjee Reshma; Li Tianbo; Koshy Shyny; Beard LaMonta L; Sharma Kapil; Carter Ethan P; Garat Chrystelle; Folkesson Hans G
Respiratory research
2007
2007-03
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1186/1465-9921-8-27" target="_blank" rel="noreferrer noopener">10.1186/1465-9921-8-27</a>