Functional analyses of coronary artery disease associated variation on chromosome 9p21 in vascular smooth muscle cells

Abstract

Variation on chromosome 9p21 is associated with risk of coronary artery disease (CAD). This genomic region contains the CDKN2A and CDKN2B genes which encode the cell cycle regulators p16(INK4a), p14(ARF) and p15(INK4b) and the ANRIL gene which encodes a non-coding RNA. Vascular smooth muscle cell (VSMC) proliferation plays an important role in the pathogenesis of atherosclerosis which causes CAD. We ascertained whether 9p21 genotype had an influence on CDKN2A/CDKN2B/ANRIL expression levels in VSMCs, VSMC proliferation and VSMC content in atherosclerotic plaques. Immunohistochemical examination showed that VSMCs in atherosclerotic lesions expressed p16(INK4a), p14(ARF) and p15(INK4b). Analyses of primary cultures of VSMCs showed that the 9p21 risk genotype was associated with reduced expression of p16(INK4a), p15(INK4b) and ANRIL (P = 1.2 × 10(-5), 1.4 × 10(-2) and 3.1 × 10(-9)) and with increased VSMC proliferation (P = 1.6 × 10(-2)). Immunohistochemical analyses of atherosclerotic plaques revealed an association of the risk genotype with reduced p15(INK4b) levels in VSMCs (P = 3.7 × 10(-2)) and higher VSMC content (P = 5.6 × 10(-4)) in plaques. The results of this study indicate that the 9p21 variation has an impact on CDKN2A and CDKN2B expression in VSMCs and influences VMSC proliferation, which likely represents an important mechanism for the association between this genetic locus and susceptibility to CAD.

Intracranial aneurysm risk factor genes: relationship with intracranial aneurysm risk in a Chinese Han population

“…CDKN2A/B has not only been demonstrated to be associated with T2DM (Cauchi et al, 2008;Scott et al, 2007), but also with atherosclerosis (Motterle et al, 2012). None of these, however, was associated with IA in our study.…”

“…CDKN2A/B has not only been associated with T2DM (Scott et al, 2007;Cauchi et al, 2008), but also with atherosclerosis (Motterle et al, 2012). TCF7L2, the transcription factor 7-like 2 gene, has been associated with T2DM, and its variants have been shown to confer T2DM risk (Scott et al, 2007;Sladek et al, 2007).…”

Association of ANRIL Gene Polymorphisms with Acute Myeloid Leukemia in an Iranian Population

“…These identified variants could be considered as predisposing factors for cancers through creating a disabled form of mentioned tumor suppressor genes. Also SNPs located in the ANRIL locus have been reported to be strongly associated with increased susceptibility to various human diseases (18)(19)(20). It is indicated that SNPs located in the 9p21 region can change the expression level of the 3 adjacent genes CDKN2A, CDKN2B, and ANRIL up to 2-fold but the expression level of CDKN2B, and ANRIL were changed in an opposite way that referred to the antisense regulating role of ANRIL on the expression of the CDKN2B gene that pointed at the consequence of modulations in ANRIL expression that increase the risk of developing human disease (20).…”

Role of noncoding RNA in vascular remodelling

“…Early studies identified antisense noncoding RNA in the INK4 locus (ANRIL), a lncRNA expressed in VSMC, which was able to regulate CDKN2A/B expression in aortic VSMC and attenuate proliferation in atherosclerosis [64][65][66] as well as modulate inflammatory responses in coronary artery disease [67].…”