Gene expression signatures, pathways and networks in carotid atherosclerosis

L Perisic, S Aldi, Y Sun, L Folkersen… - Journal of internal …, 2016 - Wiley Online Library
L Perisic, S Aldi, Y Sun, L Folkersen, A Razuvaev, J Roy, M Lengquist, S Åkesson…
Journal of internal medicine, 2016Wiley Online Library
Background Embolism from unstable atheromas in the carotid bifurcation is a major cause of
stroke. Here, we analysed gene expression in endarterectomies from patients with
symptomatic (S) and asymptomatic (AS) carotid stenosis to identify pathways linked to
plaque instability. Methods Microarrays were prepared from plaques (n= 127) and
peripheral blood samples (n= 96) of S and AS patients. Gene set enrichment, pathway
mapping and network analyses of differentially expressed genes were performed. Results …
Background
Embolism from unstable atheromas in the carotid bifurcation is a major cause of stroke. Here, we analysed gene expression in endarterectomies from patients with symptomatic (S) and asymptomatic (AS) carotid stenosis to identify pathways linked to plaque instability.
Methods
Microarrays were prepared from plaques (n = 127) and peripheral blood samples (n = 96) of S and AS patients. Gene set enrichment, pathway mapping and network analyses of differentially expressed genes were performed.
Results
These studies revealed upregulation of haemoglobin metabolism (P = 2.20E‐05) and bone resorption (P = 9.63E‐04) in S patients. Analysis of subgroups of patients indicated enrichment of calcification and osteoblast differentiation in S patients on statins, as well as inflammation and apoptosis in plaques removed >1 month compared to <2 weeks after symptom. By prediction profiling, a panel of 30 genes, mostly transcription factors, discriminated between plaques from S versus AS patients with 78% accuracy. By meta‐analysis, common gene networks associated with atherosclerosis mapped to hypoxia, chemokines, calcification, actin cytoskeleton and extracellular matrix. A set of dysregulated genes (LMOD1, SYNPO2, PLIN2 and PPBP) previously not described in atherosclerosis were identified from microarrays and validated by quantitative PCR and immunohistochemistry.
Conclusions
Our findings confirmed a central role for inflammation and proteases in plaque instability, and highlighted haemoglobin metabolism and bone resorption as important pathways. Subgroup analysis suggested prolonged inflammation following the symptoms of plaque instability and calcification as a possible stabilizing mechanism by statins. In addition, transcriptional regulation may play an important role in the determination of plaque phenotype. The results from this study will serve as a basis for further exploration of molecular signatures in carotid atherosclerosis.
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