Effect of Circular ANRIL on the Inflammatory Response of Vascular Endothelial Cells in a Rat Model of Coronary Atherosclerosis

Abstract

Background/Aims: This study aims to investigate the role of circular antisense non-coding RNA at the INK4 locus (cANRIL) in the inflammatory response of vascular endothelial cells (ECs) in a rat model of coronary atherosclerosis (AS). A rat model of AS was established with rats that were injected with a large dose of vitamin D₃ and fed a high-fat diet. Methods: Sixty Wistar rats were randomly assigned into control, model, empty vector, over-expressed cANRIL and low-expressed cANRIL groups (12 rats in each group). Sixteen weeks later, the ultrastructure of their coronary arteries was observed via transmission electron microscopy. Rat serum lipid levels were analyzed using an automatic biochemical analyzer, and their atherogenic index (AI) values were calculated. Hematoxylin and eosin staining was used to observe the endothelial morphology of rats. Additionally, rat EC apoptosis was tested via a TUNEL assay. Enzyme-linked immunosorbent assays (ELISAs) were applied to measure serum levels of interleukin-1 (IL-1), IL-6, matrix metalloproteinase-9 (MMP-9) and C-reactive protein (CRP). The cANRIL, Bax, bcl-2 and caspase-3 mRNA expression levels were measured with a quantitative real-time polymerase chain reaction (qRT-PCR). The protein expression levels of Bax, bcl-2 and caspase-3 were detected using immunohistochemistry. Results: In the control group, ECs were closely arranged with normal structures, and there was no proliferation. In the model, empty vector and over-expressed cANRIL groups, some cells were not present, and atherosclerotic plaques and thrombi appeared. However, in the under-expressed cANRIL group, the cells had a normal structure. Compared with the model and empty vector groups, the levels of total cholesterol (CHOL), triglycerides (TGs), low density lipoprotein (LDL), IL-1, IL-6, MMP-9, CRP, cANRIL, Bax, and caspase-3, AI values, and rates of EC apoptosis decreased in the low-expressed cANRIL group, while HDL (high density lipoprotein) levels and mRNA and protein expression levels of bcl-2 were increased. The changes in expression levels in the over-expressed cANRIL group were the opposite of those in the low-expressed cANRIL group. Conclusions: Our study provides evidence that reduced cANRIL expression could prevent coronary AS by reducing vascular EC apoptosis and inflammatory factor expression.

ANRIL and atherosclerosis

“…Song et al found that the overexpression of cANRIL increased the levels of serum inflammatory markers (IL‐1, IL‐6, MMP‐9, CRP and caspase‐3, etc), facilitated apoptosis of VECs and decreased the expression of bcl‐2 in the rat model of AS …”

“…(b) ANRIL regulated the expression of VEGF by activating the NF-κB signal pathway, recruiting PRC2/ p300 and regulating the expression of miR-200b. (c) The expression of ANRIL was positive correlated with the expression of CARD8 Song et al found that the overexpression of cANRIL increased the levels of serum inflammatory markers (IL-1, IL-6, MMP-9, CRP and caspase-3, etc), facilitated apoptosis of VECs and decreased the expression of bcl-2 in the rat model of AS 35,50,51. …”

The Association of Circulating MiR-29b and Interleukin-6 with Subclinical Atherosclerosis

“…Atherosclerosis as a common chronic process and many cytokines such as endothelial cells, smooth muscle cells or macrophages, could affect different stages in its progression [2, 22]. IL-6 is an important pro-inflammatory cytokine that may play a leading role in modulating the hepatic synthesis of CRP and fibrinogen [23].…”

Deep RNA Sequencing Reveals a Repertoire of Human Fibroblast Circular RNAs Associated with Cellular Responses to Herpes Simplex Virus 1 Infection

“…The circRNAs are widely distributed with biological function relatively conserved from humans to Drosophila and Archaea that also present cell typespecific and tissue-specific expression [5][6][7][8]. Moreover, circRNAs exert a variety of regulatory roles in physiological and pathological processes, including transcriptional regulation [9], alternative splicing [10], regulation of parental gene translation [11], cell cycle regulation [12], protein sponge [13], and miRNA sponge [14]. Although diverse biological functions of circRNAs have been revealed widely, little is known about their associations with virus infection and the antiviral immunity of the host.…”