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Long non-coding RNA (LncRNA) has been reported to be involved in the coronary artery disease (CAD). However, the knowledge on the association of LncRNAs is still lacking. The study is to investigate the implication of lncRNA NONHSAT112178 (lncRNAPPARσ) in the modulation of gene sets directly involved in CAD.
A microarray was performed to discovery lncRNAPPARσ. Then, a real-time fluorescence quantitative PCR (RT-qPCR) was used to verify the results. Race and Northern blot were explored to obtain the full length, and the distribution was investigated by RNA FISH. And RNA pull down and RIP were performed to study the direct binding site for lncRNA and beta-catenin.
RT-qPCR was performed to validate the microarray results, which indicated the expression of lncRNAPPARσ, neighboring protein-coding gene PPARσ, in circulating EC increased more than 4 times compared with the control group. Then, we designed and tested siRNA sequences to specifically target the transcript and successfully knocked down the expression of lncRNAPPARσ in HUVECs. Unexpectedly, we found an enhancer-like function for the lncRNAPPARσ in HUVECs, depletion of the lncRNA led to decreased activity of the neighboring protein-coding gene PPARσ, implying the expression of its target gene ADRP and ANGPTL4 reducing, moreover, due to PPARσ's trans-suppression, increasing matrix metalloproteinase-9 (MMP-9), LEF1, ICAM-1 and IL-6 production. What's more, affecting the PPARσ's pathway, the upstream was also investigated, the abundance of TCF4 was decreased significantly. The observed transcriptional enhancement by lncRNAPPARσ was mediated through the physical association with beta-catenin. This interaction is required for proper genomic localization of lncRNAPPARσ in activation of gene expression and regulation of PPARσ mediates inflammation and extra-cellular matrix remodeling in CAD.
These results reveal an unanticipated role for lncRNAPPARσ in activation of critical genes involved in extra-cellular matrix remodeling and inflammatory response to finally impact in the risk of CAD.