Expression profiling of macrophages from subjects with atherosclerosis to identify novel susceptibility genes.
Although a number of environmental risk factors for atherosclerosis have been identified, heredity seems to be a significant independent risk factor. The aim of our study was to identify novel susceptibility genes for atherosclerosis. The screening process consisted of three steps. First, expression profiles of macrophages from subjects with atherosclerosis were compared to macrophages from control subjects. Secondly, the subjects were genotyped for promoter region polymorphisms in genes with altered gene expression. Thirdly, a population of subjects with coronary heart disease and control subjects were genotyped to test for an association with identified polymorphisms that affected gene expression. Twenty-seven genes were differentially expressed in both macrophages and foam cells from subjects with atherosclerosis. Three of these genes, IRS2, CD86 and SLC11A1 were selected for further analysis. Foam cells from subjects homozygous for the C allele at the -765C-->T SNP located in the promoter region of IRS2 had increased gene expression compared to foam cells from subjects with the nonCC genotype. Also, macrophages and foam cells from subjects homozygous for allele 2 at a repeat element in the promoter region of SLC11A1 had increased gene expression compared to macrophages and foam cells from subjects with the non22 genotype. Genotyping of 512 pairs of subjects with coronary heart disease (CHD) and matched controls revealed that subjects homozygous for C of the IRS2 SNP had an increased risk for CHD; odds ratio 1.43, p=0.010. Immunohistochemical staining of human carotid plaques showed that IRS2 expression was localised to macrophages and endothelial cells in vivo. Our method provides a reliable approach for identifying susceptibility genes for atherosclerosis, and we conclude that elevated IRS2 gene expression in macrophages may be associated with an increased risk of CHD.
Hägg
Daniel A
DA
Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Göteborg, Göteborg, Sweden. daniel.hagg@medic.gu.se
Jernås
Margareta
M
Wiklund
Olle
O
Thelle
Dag S
DS
Fagerberg
Björn
B
Eriksson
Per
P
Hamsten
Anders
A
Olsson
Bob
B
Carlsson
Björn
B
Carlsson
Lena M S
LM
Svensson
Per-Arne
PA
D000483:Alleles; D050197:Atherosclerosis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D051940:B7-2 Antigen / Q000235:genetics / Q000378:metabolism; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D005487:Foam Cells / Q000166:cytology / Q000378:metabolism; D020869:Gene Expression Profiling; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000378:metabolism*; D016017:Odds Ratio; D020411:Oligonucleotide Array Sequence Analysis; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D000099173:Natural Resistance-associated Macrophage Protein 1
D051940:B7-2 Antigen; D027682:Cation Transport Proteins; D018960:Hyaluronan Receptors; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D000099173:Natural Resistance-associated Macrophage Protein 1; C497483:CD44 protein, human; C497964:CD86 protein, human; C526297:IRS2 protein, human