Tissue factor pathway inhibitor-2 gene methylation is associated with low expression in carotid atherosclerotic plaques.
BACKGROUND
The tissue factor pathway inhibitor-2 (TFPI-2) is a Kunitz-type serine-protease inhibitor which is expressed in atherosclerotic plaques. Epigenetic regulation of the TFPI-2 gene, through methylation of CpG islands, has been advocated in cancer. We hypothesized that TFPI-2 gene methylation could regulate TFPI-2 expression in atherosclerosis.


METHODS
We used Methylation Specific PCR (MSP) and pyrosequencing in order to identify 18 CpG of the TFPI-2 promoter, in 59 carotid atherosclerotic plaques and 26 control mammary arteries.


RESULTS
MSP showed methylation of the TFPI-2 gene (MSP+) in 16 plaques (27%), while no methylation (MSP-) was found in control arteries. Pyrosequencing confirmed that MSP+ plaques presented higher methylation levels than MSP- ones and arteries (p=0.03 and 0.01). Moreover, the TFPI-2 mRNA levels were lower in methylated plaques than in unmethylated ones and than in arteries (p=0.04 and <0.0001). The methylated plaques contained less lipids and macrophage infiltration than unmethylated ones. Their TFPI-2 immunoreactivity was mainly detected in the macrophages located in the media on the adventitial side, rather than in the lipid-rich core.


CONCLUSIONS
Methylation of the TFPI-2 gene takes place in atherosclerotic plaques and is associated with decreased TFPI-2 expression. The place of this process in atherosclerosis progression remains to be investigated.
Zawadzki
Christophe
C
Université de Lille 2, EA-2693, F-59045 Lille, France. c-zawadzki@chru-lille.fr
Chatelain
Nicolas
N
Delestre
Marianne
M
Susen
Sophie
S
Quesnel
Bruno
B
Juthier
Francis
F
Jeanpierre
Emmanuelle
E
Azzaoui
Richard
R
Corseaux
Delphine
D
Breyne
Joke
J
Torpier
Gérard
G
Staels
Bart
B
Van Belle
Eric
E
Jude
Brigitte
B
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D002339:Carotid Arteries / Q000737:chemistry* / Q000473:pathology / Q000601:surgery; D002340:Carotid Artery Diseases / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D016022:Case-Control Studies; D018899:CpG Islands; D019175:DNA Methylation; D015536:Down-Regulation; D016894:Endarterectomy, Carotid; D005260:Female; D005838:Genotype; D006023:Glycoproteins / Q000032:analysis / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010641:Phenotype; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis
D006023:Glycoproteins; D012333:RNA, Messenger; C021240:tissue-factor-pathway inhibitor 2