85-kDa cytosolic phospholipase A2 group IValpha gene promoter polymorphisms in patients with severe asthma: a gene expression and case-control study.
Cytosolic phospholipase A(2) (cPLA(2)) group IValpha is a critical enzyme involved in the liberation of arachidonic acid from cellular membranes. cPLA(2)(-/-) mice have reduced allergen-induced bronchoconstriction and bronchial hyperresponsiveness. The goal of this study was to investigate polymorphisms of the (CA)(n) and (T)(n) microsatellites and surrounding regions in the cPLA(2)alpha gene promoter. We analysed the cPLA(2) promoter regions containing (CA)(n) and (T)(n) repeats in 87 patients with severe asthma and in 48 control subjects by bidirectional sequencing. Functional studies were performed utilizing reporter genes derived from subjects with varying numbers of these repeats, and on constructs with a series of deletions. We found that the (CA)(n) and (T)(n) regions are polymorphic and that constructs with CA or T repeats or CA and T repeats deleted revealed, respectively, a 41.8 +/- 7%, 22.3 +/- 5% and 100 +/- 20% increase in reporter gene activity. A lower number of CA or T repeats caused higher cPLA(2) promoter luciferase activity. The group of shorter alleles of the (CA)(n) microsatellite region (n = 12-18) (P(cor) = 0.00006), and the group of shorter alleles of (T)(n) repeats region (n = 17-38) (P(cor) = 0.0039) occurred significantly more often in patients with severe asthma. We also found novel SNPs in positions -292 C > G, -185 A > C, -180 T > C and -165 A > C. Two of them were associated with the severe asthma phenotype: -180T allele (P(cor) = 0.03996) and -185 A allele (P(cor) = 0.03966). These results demonstrate that (CA)(n) and (T)(n) repeats may have an influence on cPLA(2) transcription which might play a role in severe asthma pathogenesis.
Department of Immunopathology, Medical University of Lodz, Poland.
M
M
Sokolowska
M
M
Borowiec
A
A
Ptasinska
M
M
Cieslak
J H
JH
Shelhamer
M L
ML
Kowalski
R
R
Pawliczak
D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D005786:Gene Expression Regulation; D005787:Gene Frequency; D017930:Genes, Reporter; D020022:Genetic Predisposition to Disease; D005838:Genotype; D054513:Group IV Phospholipases A2; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D010741:Phospholipases A / Q000235:genetics*; D054467:Phospholipases A2; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic / Q000235:genetics; D014407:Tumor Cells, Cultured
D010741:Phospholipases A; D054513:Group IV Phospholipases A2; C516389:PLA2G4A protein, human; D054467:Phospholipases A2