Abstract
BackgroundProstaglandin E2(PGE2) increases pulmonary vascular permeability by activation of the PGE2receptor 3 (EP3) which may explain adverse pulmonary effects of the EP1/EP3receptor agonist sulprostone in patients. PGE2also contributes to pulmonary edema in response to platelet-activating factor (PAF). PAF increases endothelial permeability by recruiting the cation channel transient receptor potential canonical 6 (TRPC6) to endothelial caveolaeviaacid sphingomyelinase (ASMase). Yet, the roles of PGE2and EP3in this pathway are unknown. We hypothesized that EP3receptor activation may increase pulmonary vascular permeability by activation of TRPC6, and thus, synergize with ASMase-mediated TRPC6 recruitment in PAF-induced lung edema.
MethodsIn isolated lungs, we measured increases in endothelial Ca2+(ΔCa2+) or lung weight (Δweight), and endothelial caveolar TRPC6 abundance as well as phosphorylation.
ResultsPAF-induced ΔCa2+和wΔeight were attenuated in EP3-deficient mice. Sulprostone replicated PAF-induced ΔCa2+和wΔeight which were blocked by pharmacologic/genetic inhibition of TRPC6, ASMase, or Src-family kinases (SrcFK). PAF, yet not sulprostone, increased TRPC6 abundance in endothelial caveolae. Immunoprecipitation revealed PAF- and sulprostone-induced tyrosine-phosphorylation of TRPC6 that was prevented by inhibition of phospholipase C (PLC) or SrcFK. PLC inhibition also blocked sulprostone-induced ΔCa2+和wΔeight, as did inhibition of SrcFK or Gisignaling.
ConclusionsEP3activation triggers pulmonary edemaviaGi-dependent activation of PLC and subsequent SrcFK-dependent tyrosine phosphorylation of TRPC6. In PAF-induced lung edema this TRPC6 activation coincides with ASMase-dependent caveolar recruitment of TRPC6, resulting in rapid endothelial Ca2+influx and barrier failure.
Footnotes
This manuscript has recently been accepted for publication in theEuropean Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of theERJonline. Please open or download the PDF to view this article.
Conflict of interest: Tian Jiang has nothing to disclose.
Conflict of interest: Rudi Samapati has nothing to disclose.
Conflict of interest: Sergej Klassen has nothing to disclose.
Conflict of interest: Disi Lei has nothing to disclose.
Conflict of interest: Vera Jankowski has nothing to disclose.
Conflict of interest: Szandor Simmons has nothing to disclose.
Conflict of interest: Jun Yin has nothing to disclose.
Conflict of interest: Christoph Arenz has nothing to disclose.
Conflict of interest: Alexander Dietrich has nothing to disclose.
Conflict of interest: Thomas Gudermann has nothing to disclose.
Conflict of interest: Dieter Adam has nothing to disclose.
Conflict of interest: Michael Schaefer has nothing to disclose.
Conflict of interest: Joachim Jankowski has nothing to disclose.
Conflict of interest: Veit Flockerzi has nothing to disclose.
Conflict of interest: Rolf Nüsing has nothing to disclose.
Conflict of interest: Stefan Uhlig has nothing to disclose.
Conflict of interest: Wolfgang M. Kuebler has nothing to disclose.
- ReceivedOctober 4, 2021.
- AcceptedFebruary 17, 2022.
- Copyright ©The authors 2022. For reproduction rights and permissions contactpermissions{at}ersnet.org