Department of Internal Medicine II, Regensburg University Medical Center, Regensburg, Germany.
Atherosclerosis. 2013 Apr;227(2):244-9. doi: 10.1016/j.atherosclerosis.2012.12.030. Epub 2013 Jan 17.
Genome-wide association studies identified a risk haplotype on chromosome 9p21.3 to be associated with coronary artery disease (CAD) and myocardial infarction (MI). Since this region does not contain a clear candidate gene with known pathophysiology, we performed a haplotype-specific expression study in human macrophages during pro-inflammatory stimulation to investigate the locus-dependent expression patterns in a model of atherosclerosis, the underlying cause for CAD and MI.
Blood samples were taken from 40 male stable MI patients either homozygous for 9p21.3 risk (n = 20) or non-risk haplotype (n = 20) as well as from 28 healthy male individuals (n = 14 for each haplotype). Monocytes were isolated by density gradient centrifugation followed by differentiation into macrophages via M-CSF. Macrophages were either incubated with a pro-inflammatory IFNγ-LPS cocktail or kept untreated as controls. After 24 h, RNA was isolated and applied to Affymetrix Human Exon 1.0 ST Arrays.
Macrophages from MI patients and controls stratified for 9p21.3 haplotypes, exhibited marked differences in gene expression. Most pronounced differences were found in inflammatory mediators, like the chemokines CCL8 and CCL2 and the lectines CLEC4E and CLEC5A. Differences in expression changes could be seen most obviously during inflammatory stimulation for both, the interleukins IL12B and IL1B, and members of metallothionein gene family.
These findings show that gene expression is different in 9p21.3 haplotype-stratified macrophages. While these effects are relatively small in our in vitro model of atherosclerosis, these biological effects may contribute to a long term effect in risk haplotype carriers increasing susceptibility to CAD and MI.
全基因组关联研究鉴定出染色体 9p21.3 上的风险单倍型与冠状动脉疾病 (CAD) 和心肌梗死 (MI) 相关。由于该区域不包含具有已知病理生理学的明确候选基因，因此我们在炎症刺激期间对人类巨噬细胞进行了特定于单倍型的表达研究，以调查动脉粥样硬化模型中基因座依赖性表达模式，这是 CAD 和 MI 的根本原因。
从 40 名男性稳定 MI 患者中采集血液样本，这些患者要么为 9p21.3 风险单倍型 (n = 20) 纯合子，要么为非风险单倍型 (n = 20)，并从 28 名健康男性个体中采集血液样本 (n = 14 个风险单倍型) 。通过密度梯度离心分离单核细胞，然后通过 M-CSF 将其分化为巨噬细胞。巨噬细胞要么用促炎 IFNγ-LPS 鸡尾酒孵育，要么作为对照保持未处理状态。孵育 24 小时后，分离 RNA 并应用于 Affymetrix Human Exon 1.0 ST Arrays。
按 9p21.3 单倍型分层的 MI 患者和对照者的巨噬细胞表现出明显的基因表达差异。最明显的差异是在炎症介质中发现的，如趋化因子 CCL8 和 CCL2 以及凝集素 CLEC4E 和 CLEC5A。在炎症刺激期间，白细胞介素 IL12B 和 IL1B 以及金属硫蛋白基因家族成员的表达变化差异最为明显。
这些发现表明，9p21.3 单倍型分层的巨噬细胞的基因表达不同。虽然在我们的动脉粥样硬化体外模型中这些影响相对较小，但这些生物学效应可能会导致风险单倍型携带者长期易感性增加，从而增加 CAD 和 MI 的易感性。
