Mechanism of action of novel lung edema therapeutic AP301 by activation of the epithelial sodium channel

Waheed Shabbir, Parastoo Scherbaum-Hazemi, Susan Tzotzos, Bernhard Fischer, Hendrik Fischer, Helmut Pietschmann, Rudolf Lucas, Rosa Lemmens-Gruber

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

AP301 [Cyclo(CGQRETPEGAEAKPWYC)], a cyclic peptide comprising the human tumor necrosis factor lectin-like domain (TIP domain) sequence, is currently being developed as a treatment for lung edema and has been shown to reduce extravascular lung water and improve lung function in mouse, rat, and pig models. The current paradigm for liquid homeostasis in the adult mammalian lung is that passive apical uptake of sodium via the amiloride-sensitive epithelial Na+ channel (ENaC) and nonselective cyclic-nucleotide-gated cation channels creates the major driving force for reabsorption of water through the alveolar epithelium in addition to other ion channels such as potassium and chloride channels. AP301 can increase amiloride-sensitive current in A549 cells as well as in freshly isolated type II alveolar epithelial cells from different species. ENaC is expressed endogenously in all of these cell types. Consequently, this study was undertaken to determine whether ENaC is the specific target of AP301. The effect of AP301 in A549 cells as well as in human embryonic kidney cells and Chinese hamster ovary cells heterologously expressing human ENaC subunits (α, β, γ, and δ) was measured in patch clamp experiments. The congener TIP peptide AP318 [Cyclo(4-aminobutanoic acid-GQRETPEGAEAKPWYD)] activated ENaC by increasing single-channel open probability. AP301 increased current in proteolytically activated (cleaved) but not near-silent (uncleaved) ENaC in a reversible manner. αβγ- or δβγ-ENaC coexpression was required for maximal activity. No increase in current was observed after deglycosylation of extracellular domains of ENaC. Thus, our data suggest that the specific interaction of AP301 with both endogenously and heterologously expressed ENaC requires precedent binding to glycosylated extracellular loop(s).

Original languageEnglish (US)
Pages (from-to)899-910
Number of pages12
JournalMolecular Pharmacology
Volume84
Issue number6
DOIs
StatePublished - Dec 1 2013

Fingerprint

Epithelial Sodium Channels
Edema
Lung
Therapeutics
Amiloride
Cyclic Nucleotide-Gated Cation Channels
Extravascular Lung Water
Alveolar Epithelial Cells
Cyclic Peptides
Chloride Channels
Potassium Chloride
Potassium Channels
Cricetulus
Ion Channels
Lectins
Ovary
Homeostasis
Swine
Epithelium
Sodium

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology

Cite this

Shabbir, W., Scherbaum-Hazemi, P., Tzotzos, S., Fischer, B., Fischer, H., Pietschmann, H., ... Lemmens-Gruber, R. (2013). Mechanism of action of novel lung edema therapeutic AP301 by activation of the epithelial sodium channel. Molecular Pharmacology, 84(6), 899-910. https://doi.org/10.1124/mol.113.089409

Mechanism of action of novel lung edema therapeutic AP301 by activation of the epithelial sodium channel. / Shabbir, Waheed; Scherbaum-Hazemi, Parastoo; Tzotzos, Susan; Fischer, Bernhard; Fischer, Hendrik; Pietschmann, Helmut; Lucas, Rudolf; Lemmens-Gruber, Rosa.

In: Molecular Pharmacology, Vol. 84, No. 6, 01.12.2013, p. 899-910.

Research output: Contribution to journalArticle

Shabbir, W, Scherbaum-Hazemi, P, Tzotzos, S, Fischer, B, Fischer, H, Pietschmann, H, Lucas, R & Lemmens-Gruber, R 2013, 'Mechanism of action of novel lung edema therapeutic AP301 by activation of the epithelial sodium channel', Molecular Pharmacology, vol. 84, no. 6, pp. 899-910. https://doi.org/10.1124/mol.113.089409
Shabbir W, Scherbaum-Hazemi P, Tzotzos S, Fischer B, Fischer H, Pietschmann H et al. Mechanism of action of novel lung edema therapeutic AP301 by activation of the epithelial sodium channel. Molecular Pharmacology. 2013 Dec 1;84(6):899-910. https://doi.org/10.1124/mol.113.089409
Shabbir, Waheed ; Scherbaum-Hazemi, Parastoo ; Tzotzos, Susan ; Fischer, Bernhard ; Fischer, Hendrik ; Pietschmann, Helmut ; Lucas, Rudolf ; Lemmens-Gruber, Rosa. / Mechanism of action of novel lung edema therapeutic AP301 by activation of the epithelial sodium channel. In: Molecular Pharmacology. 2013 ; Vol. 84, No. 6. pp. 899-910.
@article{029bfda108cb4a39803e0f6b0e69b018,
title = "Mechanism of action of novel lung edema therapeutic AP301 by activation of the epithelial sodium channel",
abstract = "AP301 [Cyclo(CGQRETPEGAEAKPWYC)], a cyclic peptide comprising the human tumor necrosis factor lectin-like domain (TIP domain) sequence, is currently being developed as a treatment for lung edema and has been shown to reduce extravascular lung water and improve lung function in mouse, rat, and pig models. The current paradigm for liquid homeostasis in the adult mammalian lung is that passive apical uptake of sodium via the amiloride-sensitive epithelial Na+ channel (ENaC) and nonselective cyclic-nucleotide-gated cation channels creates the major driving force for reabsorption of water through the alveolar epithelium in addition to other ion channels such as potassium and chloride channels. AP301 can increase amiloride-sensitive current in A549 cells as well as in freshly isolated type II alveolar epithelial cells from different species. ENaC is expressed endogenously in all of these cell types. Consequently, this study was undertaken to determine whether ENaC is the specific target of AP301. The effect of AP301 in A549 cells as well as in human embryonic kidney cells and Chinese hamster ovary cells heterologously expressing human ENaC subunits (α, β, γ, and δ) was measured in patch clamp experiments. The congener TIP peptide AP318 [Cyclo(4-aminobutanoic acid-GQRETPEGAEAKPWYD)] activated ENaC by increasing single-channel open probability. AP301 increased current in proteolytically activated (cleaved) but not near-silent (uncleaved) ENaC in a reversible manner. αβγ- or δβγ-ENaC coexpression was required for maximal activity. No increase in current was observed after deglycosylation of extracellular domains of ENaC. Thus, our data suggest that the specific interaction of AP301 with both endogenously and heterologously expressed ENaC requires precedent binding to glycosylated extracellular loop(s).",
author = "Waheed Shabbir and Parastoo Scherbaum-Hazemi and Susan Tzotzos and Bernhard Fischer and Hendrik Fischer and Helmut Pietschmann and Rudolf Lucas and Rosa Lemmens-Gruber",
year = "2013",
month = "12",
day = "1",
doi = "10.1124/mol.113.089409",
language = "English (US)",
volume = "84",
pages = "899--910",
journal = "Molecular Pharmacology",
issn = "0026-895X",
publisher = "American Society for Pharmacology and Experimental Therapeutics",
number = "6",

}

TY - JOUR

T1 - Mechanism of action of novel lung edema therapeutic AP301 by activation of the epithelial sodium channel

AU - Shabbir, Waheed

AU - Scherbaum-Hazemi, Parastoo

AU - Tzotzos, Susan

AU - Fischer, Bernhard

AU - Fischer, Hendrik

AU - Pietschmann, Helmut

AU - Lucas, Rudolf

AU - Lemmens-Gruber, Rosa

PY - 2013/12/1

Y1 - 2013/12/1

N2 - AP301 [Cyclo(CGQRETPEGAEAKPWYC)], a cyclic peptide comprising the human tumor necrosis factor lectin-like domain (TIP domain) sequence, is currently being developed as a treatment for lung edema and has been shown to reduce extravascular lung water and improve lung function in mouse, rat, and pig models. The current paradigm for liquid homeostasis in the adult mammalian lung is that passive apical uptake of sodium via the amiloride-sensitive epithelial Na+ channel (ENaC) and nonselective cyclic-nucleotide-gated cation channels creates the major driving force for reabsorption of water through the alveolar epithelium in addition to other ion channels such as potassium and chloride channels. AP301 can increase amiloride-sensitive current in A549 cells as well as in freshly isolated type II alveolar epithelial cells from different species. ENaC is expressed endogenously in all of these cell types. Consequently, this study was undertaken to determine whether ENaC is the specific target of AP301. The effect of AP301 in A549 cells as well as in human embryonic kidney cells and Chinese hamster ovary cells heterologously expressing human ENaC subunits (α, β, γ, and δ) was measured in patch clamp experiments. The congener TIP peptide AP318 [Cyclo(4-aminobutanoic acid-GQRETPEGAEAKPWYD)] activated ENaC by increasing single-channel open probability. AP301 increased current in proteolytically activated (cleaved) but not near-silent (uncleaved) ENaC in a reversible manner. αβγ- or δβγ-ENaC coexpression was required for maximal activity. No increase in current was observed after deglycosylation of extracellular domains of ENaC. Thus, our data suggest that the specific interaction of AP301 with both endogenously and heterologously expressed ENaC requires precedent binding to glycosylated extracellular loop(s).

AB - AP301 [Cyclo(CGQRETPEGAEAKPWYC)], a cyclic peptide comprising the human tumor necrosis factor lectin-like domain (TIP domain) sequence, is currently being developed as a treatment for lung edema and has been shown to reduce extravascular lung water and improve lung function in mouse, rat, and pig models. The current paradigm for liquid homeostasis in the adult mammalian lung is that passive apical uptake of sodium via the amiloride-sensitive epithelial Na+ channel (ENaC) and nonselective cyclic-nucleotide-gated cation channels creates the major driving force for reabsorption of water through the alveolar epithelium in addition to other ion channels such as potassium and chloride channels. AP301 can increase amiloride-sensitive current in A549 cells as well as in freshly isolated type II alveolar epithelial cells from different species. ENaC is expressed endogenously in all of these cell types. Consequently, this study was undertaken to determine whether ENaC is the specific target of AP301. The effect of AP301 in A549 cells as well as in human embryonic kidney cells and Chinese hamster ovary cells heterologously expressing human ENaC subunits (α, β, γ, and δ) was measured in patch clamp experiments. The congener TIP peptide AP318 [Cyclo(4-aminobutanoic acid-GQRETPEGAEAKPWYD)] activated ENaC by increasing single-channel open probability. AP301 increased current in proteolytically activated (cleaved) but not near-silent (uncleaved) ENaC in a reversible manner. αβγ- or δβγ-ENaC coexpression was required for maximal activity. No increase in current was observed after deglycosylation of extracellular domains of ENaC. Thus, our data suggest that the specific interaction of AP301 with both endogenously and heterologously expressed ENaC requires precedent binding to glycosylated extracellular loop(s).

UR - http://www.scopus.com/inward/record.url?scp=84888873571&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84888873571&partnerID=8YFLogxK

U2 - 10.1124/mol.113.089409

DO - 10.1124/mol.113.089409

M3 - Article

C2 - 24077967

AN - SCOPUS:84888873571

VL - 84

SP - 899

EP - 910

JO - Molecular Pharmacology

JF - Molecular Pharmacology

SN - 0026-895X

IS - 6

ER -