Prostaglandin E(2) protects human lung fibroblasts from cigarette smoke extract-induced apoptosis via EP(2) receptor activation.
Prostaglandin E(2) (PGE(2)) has been shown to have a strong cytoprotective effect, inhibiting apoptosis. In the present study, we evaluated whether PGE(2) has a protective effect on cigarette smoke extract (CSE)-induced apoptosis in human lung fibroblasts. Apoptosis was assessed by various methods, including DNA content analysis. CSE (15%-20%) led to apoptosis and induced imbalance in favor of pro- over anti-apoptotic protein expression and activated caspases. PGE(2) blocked CSE-induced apoptosis and modulated the balance of pro- and anti-apoptotic proteins and decreased the activation of caspases. This anti-apoptotic effect was mediated via EP(2) receptor activation as the EP(2) agonist butaprost mimicked PGE(2) activity and siRNA for the EP(2) receptor blocked it. An adenylyl cyclase inhibitor was found to abolish the PGE(2)-mediated cytoprotective effect. Correspondingly, c-AMP analogs blocked CSE-induced apoptosis. Consistently, the protein kinase A (PKA) inhibitor KT-5720 abolished PGE(2)-mediated protection. PGE(2) and butaprost phosphorylated Bad and KT-5720 blocked phosphorylation. These results suggest that PGE(2) inhibits CSE-induced apoptosis via EP(2) receptor activation and activation of PKA, which leads to an alteration in the balance between pro- and anti-apoptotic factors. Through such a mechanism, PGE(2) may alter survival of cells in the smoke-exposed lungs, thus affecting the pathogenesis of cigarette smoke-induced disease.
Sugiura
Hisatoshi
H
University of Nebraska Medical Center, Nebraska Medical Center, Omaha, Nebraska 68198, USA.
Liu
Xiangde
X
Togo
Shinsaku
S
Kobayashi
Tetsu
T
Shen
Lei
L
Kawasaki
Shin
S
Kamio
Koichiro
K
Wang
Xing Qi
XQ
Mao
Li Jun
LJ
Rennard
Stephen I
SI
D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000378:metabolism; D000527:Alprostadil / Q000031:analogs & derivatives / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D002227:Carbazoles / Q000494:pharmacology; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D016048:Dideoxyadenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D015232:Dinoprostone / Q000031:analogs & derivatives / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D008168:Lung / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D011758:Pyrroles / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D018078:Receptors, Prostaglandin E / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D058307:Receptors, Prostaglandin E, EP2 Subtype; D015398:Signal Transduction / Q000187:drug effects; D012906:Smoke / Q000009:adverse effects*; D013876:Thiophenes / Q000494:pharmacology; D014026:Nicotiana; D014230:Triazoles / Q000494:pharmacology
C092396:17-phenyltrinorprostaglandin E2; D000067956:Adenylyl Cyclase Inhibitors; D002227:Carbazoles; D004791:Enzyme Inhibitors; D007211:Indoles; C508711:L-161982; C545644:PTGER2 protein, human; D011758:Pyrroles; D034741:RNA, Small Interfering; D018078:Receptors, Prostaglandin E; D058307:Receptors, Prostaglandin E, EP2 Subtype; D012906:Smoke; D013876:Thiophenes; D014230:Triazoles; D016048:Dideoxyadenosine; C016767:sulprostone; C057416:KT 5720; C021008:2',5'-dideoxyadenosine; D017868:Cyclic AMP-Dependent Protein Kinases; D020169:Caspases; D000262:Adenylyl Cyclases; D000527:Alprostadil; C048491:butaprost; D015232:Dinoprostone