Expression profiling identifies smooth muscle cell diversity within human intima and plaque fibrous cap: loss of RGS5 distinguishes the cap.
BACKGROUND
The fibrous cap of the atherosclerotic lesion is believed to be critical to stability because disruption of the cap is the final event leading to plaque rupture. We have, therefore, used expression arrays to define the phenotype of the cap and other plaque components.


RESULTS
To identify unique expression programs able to distinguish the smooth muscle of the cap from other plaque smooth muscle cells, RNA profiles were determined in human carotid artery media, nonatherosclerotic adjacent intima, fibrous cap of advanced atherosclerotic plaques, and whole advanced plaque with cDNA arrays covering 21,000 or 26,000 Unigene clusters. The molecular signature of each tissue was dominated by a core gene-set with differential expression of <1% of clusters assayed.


CONCLUSIONS
Both intima and cap expressed novel genes not previously associated with SMC pathology. If the cap is derived from a unique subpopulation, this pattern is the signature of that particular set of cells. The loss of RGS5 in the fibrous cap is of particular interest because of its role in vessel development and physiology.
Adams
Lawrence D
LD
Department of Pathology, Center for Cardiovascular Biology and Regenerative Medicine, University of Washington School of Medicine, Seattle, USA. ladams@u.washington.edu
Geary
Randolph L
RL
Li
Jing
J
Rossini
Anthony
A
Schwartz
Stephen M
SM
D002339:Carotid Arteries / Q000473:pathology / Q000502:physiology; D002340:Carotid Artery Diseases / Q000235:genetics* / Q000473:pathology*; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D009131:Muscle, Smooth, Vascular / Q000473:pathology / Q000502:physiology*; D010641:Phenotype; D020710:RGS Proteins / Q000235:genetics* / Q000378:metabolism; D017539:Tunica Intima / Q000473:pathology / Q000502:physiology; D017540:Tunica Media / Q000473:pathology / Q000502:physiology
D020710:RGS Proteins; C491349:RGS5 protein, human