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Comprehensive gene expression profiling reveals synergistic functional networks in cerebral vessels after
Wei-Yi Ong1, Mary Pei-Ern Ng, Sau-Yeen Loke
1Department of Anatomy, National University of Singapore, Singapore. wei_yi_ong@nuhs.edu.sg
Insights
Hypertension and hypercholesterolemia, major stroke risk factors, induce similar gene expression changes in cerebral arteries. These overlapping molecular pathways in intracranial large artery disease may explain how combined risks worsen stroke.
Area of Science:
- Vascular biology
- Genomics
- Stroke research
Background:
- Intracranial large artery disease (ICLAD) is a significant cause of stroke, particularly in certain ethnic groups.
- Gene expression changes in cerebral arteries affected by stroke risk factors like hypertension and hypercholesterolemia are not well understood.
Purpose of the Study:
- To compare comprehensive gene expression profiles in the middle cerebral artery (MCA) of rabbits under hypertensive and/or hypercholesterolemic conditions.
- To identify common and distinct molecular pathways affected by these two major stroke risk factors.
Main Methods:
- Utilized the 2-Kidney-1-Clip method for hypertension and dietary cholesterol for hypercholesterolemia in New Zealand White rabbits.
- Performed microarray analysis and Ingenuity Pathway Analysis on MCA tissues.
- Verified increased hepatocyte nuclear factor 4A (HNF4A) expression in aortic tissue.
Main Results:
- Hypertension induced up-regulation of genes in networks involving UBC, P38 MAPK, ERK, NFkB, SERPINB2, MMP1, and APP.
- Hypercholesterolemia affected similar nodal molecules, with up-regulated common genes including UBC, SERPINB2, TNF, HNF4A, and APP.
- Despite low gene overlap, both conditions impacted related molecular pathways, suggesting a shared mechanism in cerebral artery disease.
Conclusions:
- Hypertension and hypercholesterolemia trigger overlapping gene expression patterns in cerebral arteries.
- These shared molecular pathways may contribute to the synergistic effect of risk factors in the pathogenesis of ICLAD.
- Understanding these pathways offers potential targets for stroke prevention and treatment.
Abstract:
Atherosclerotic stenosis of cerebral arteries or intracranial large artery disease (ICLAD) is a major cause of stroke especially in Asians, Hispanics and Africans, but relatively little is known about gene expression changes in vessels at risk. This study compares comprehensive gene expression profiles in the middle cerebral artery (MCA) of New Zealand White rabbits exposed to two stroke risk factors i.e. hypertension and/or hypercholesterolemia, by the 2-Kidney-1-Clip method, or dietary supplementation with cholesterol. Microarray and Ingenuity Pathway Analyses of the MCA of the hypertensive rabbits showed up-regulated genes in networks containing the node molecules: UBC (ubiquitin), P38 MAPK, ERK, NFkB, SERPINB2, MMP1 and APP (amyloid precursor protein); and down-regulated genes related to MAPK, ERK 1/2, Akt, 26 s proteasome, histone H3 and UBC. The MCA of hypercholesterolemic rabbits showed differentially expressed genes that are surprisingly, linked to almost the same node molecules as the hypertensive rabbits, despite a relatively low percentage of 'common genes' (21 and 7%) between the two conditions. Up-regulated common genes were related to: UBC, SERPINB2, TNF, HNF4A (hepatocyte nuclear factor 4A) and APP, and down-regulated genes, related to UBC. Increased HNF4A message and protein were verified in the aorta. Together, these findings reveal similar nodal molecules and gene pathways in cerebral vessels affected by hypertension or hypercholesterolemia, which could be a basis for synergistic action of risk factors in the pathogenesis of ICLAD.
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