Gene Expression in Macrophage-Rich Inflammatory Cell Infiltrates in Human Atherosclerotic Lesions as Studied by Laser Microdissection and DNA Array

Abstract

Objective-Inflammatory cells play an important role in atherogenesis. However, more information is needed about their gene expression profiles in human lesions. Methods and Results-We used laser microdissection (LMD) to isolate macrophage-rich shoulder areas from human lesions. Gene expression profiles in isolated cells were analyzed by cDNA array and compared with expression patterns in normal intima and THP-1 macrophages. Upregulation of 72 genes was detected with LMD and included 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, interferon regulatory factor-5 (IRF-5), colony stimulating factor (CSF) receptors, CD11a/CD18 integrins, interleukin receptors, CD43, calmodulin, nitric oxide synthase (NOS), and extracellular superoxide dismutase (SOD). Several of these changes were also present in PMA-stimulated THP-1 macrophages in vitro. On the other hand, expression of several genes, such as VEGF, tissue factor pathway inhibitor 2, and apolipoproteins C-I and C-II, decreased. Conclusions-Overexpression of HMG-CoA reductase in macrophage-rich lesion areas may explain some beneficial effects of statins, which can also modulate increased expression of CD11a/CD18 and CD43 found in microdissected cells. We also found increased expression of CSF receptors, IRF-5, and interleukin receptors, which could become useful therapeutic targets for the treatment of atherosclerotic diseases.

Genome-Wide Expression Studies of Atherosclerosis

“…16,22 However, a detailed microscopic characterization of human samples has only been given in 2 studies. 18,28 Consequently, this lack of transparency in the morphology of analyzed samples hinders extrapolation and comparison of gene expression results. In only a minority of studies, 10,[25][26][27][28] the expression profiles of samples with a uniform cell content have been compared.…”

“…18,28 Consequently, this lack of transparency in the morphology of analyzed samples hinders extrapolation and comparison of gene expression results. In only a minority of studies, 10,[25][26][27][28] the expression profiles of samples with a uniform cell content have been compared. However, one of these studies compares the transcriptome of SMC-enriched and macrophage-enriched cell populations 28 and does not exploit the advantage of isolating relatively pure cell populations.…”

“…In only a minority of studies, 10,[25][26][27][28] the expression profiles of samples with a uniform cell content have been compared. However, one of these studies compares the transcriptome of SMC-enriched and macrophage-enriched cell populations 28 and does not exploit the advantage of isolating relatively pure cell populations. Last, but not least, we observed an evolution from analyzing pools of samples toward individual samples, which has a positive effect on the possibilities for downstream statistical analysis.…”

“…To compare gene expression patterns from different parts of the atherosclerotic vessel wall, laser capture microdissection 10,28 and macrodissection 26,27 have been used to isolate relatively pure cell populations from whole mount specimen (Table 3). As mentioned, these techniques help to overcome one of the shortcomings of the whole mount approach as it corrects for the cellular composition of a sample.…”

Distinctive Expression of Chemokines and Transforming Growth Factor-β Signaling in Human Arterial Endothelium during Atherosclerosis

“…14 In addition, T7 RNA polymerase-mediated mRNA amplification has enabled reliable microarray gene expression profiling from small quantities of input mRNA, both in vitro and ex vivo. [15][16][17][18][19][20] To identify only the genes that are potentially functionally involved in lesion formation, irrespective of arterial location and individual differences, we used a diverse set of human large arteries of which the types as well as the locations were randomly selected. To minimize the individual or local confounders, we envisioned a paired comparative approach thereby enabling us to study gene expression differences in a limited set of arteries.…”