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Hypermethylation of PTGER2 confers prostaglandin E2 resistance in fibrotic fibroblasts from humans and mice.
- Source :
-
The American journal of pathology [Am J Pathol] 2010 Nov; Vol. 177 (5), pp. 2245-55. Date of Electronic Publication: 2010 Oct 01. - Publication Year :
- 2010
-
Abstract
- Idiopathic pulmonary fibrosis (IPF) is a devastating lung disease that is characterized by excessive proliferation of fibroblasts. The lipid mediator prostaglandin E2 (PGE2) has the capacity to limit fibrosis through its inhibition of numerous functions of these fibroblasts; however, in the setting of fibrosis, fibroblasts have been shown to be resistant to PGE2. We have linked such resistance to decreased expression levels of the E prostanoid 2 (EP2) receptor. In this study, in fibroblasts from both mice and humans with pulmonary fibrosis, we show that DNA hypermethylation is responsible for diminished EP2 expression levels and PGE2 resistance. Bisulfite sequencing of the prostaglandin E receptor 2 gene (PTGER2) promoter revealed that fibrotic fibroblasts exhibit greater PTGER2 methylation than nonfibrotic control cells. Treatment with the DNA methylation inhibitors 5-aza-2'-deoxycytidine and zebularine as well as DNA methyltransferase-specific siRNA decreased PTGER2 methylation, increased EP2 mRNA and protein expression levels, and restored PGE2 responsiveness in fibrotic fibroblasts but not in nonfibrotic controls. PTGER2 promoter hypermethylation was driven by an increase in Akt signal transduction. In addition to results described for the PTGER2 promoter, fibrotic fibroblasts also exhibited increased global DNA methylation. These findings demonstrate that the down-regulation of PTGER2 and consequent PGE2 resistance are both mediated by DNA hypermethylation; we identified increased Akt signal transduction as a novel mechanism that promotes DNA hypermethylation during fibrogenesis.
- Subjects :
- Animals
Cells, Cultured
DNA Methylation
DNA Modification Methylases genetics
DNA Modification Methylases metabolism
Fibroblasts cytology
Fibrosis pathology
Humans
Mice
Mice, Inbred C57BL
PTEN Phosphohydrolase metabolism
Promoter Regions, Genetic
Proto-Oncogene Proteins c-akt metabolism
RNA, Small Interfering genetics
RNA, Small Interfering metabolism
Receptors, Prostaglandin E, EP2 Subtype genetics
Signal Transduction genetics
Dinoprostone pharmacology
Fibroblasts metabolism
Fibroblasts pathology
Receptors, Prostaglandin E, EP2 Subtype metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1525-2191
- Volume :
- 177
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- The American journal of pathology
- Publication Type :
- Academic Journal
- Accession number :
- 20889571
- Full Text :
- https://doi.org/10.2353/ajpath.2010.100446