Transcriptome-Wide N6-Methyladenosine Alternations in Pulmonary Arteries of Monocrotaline-Induced Pulmonary Arterial Hypertension in Rats and Novel Therapeutic Targets

N6-methyladenosine (m6A) is a post-transcriptional epigenetic change with transcriptional stability and functionality regulated by specific m6A-modifying enzymes. However, the significance of genes modified by m6A and enzymes specific to m6A regulation in the context of pulmonary arterial hypertension (PAH) remains largely unexplored. MeRIP-seq and RNA-seq were applied to explore variances in m6A and RNA expression within the pulmonary artery tissues of control and monocrotaline-induced PAH rats. Functional enrichments were analyzed using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. To screen candidate m6A-related genes, the STRING and Metascape databases were used to construct a protein-protein interaction network followed by a real-time PCR validation of their expression. The expression level of an m6A regulator was further investigated using immunohistochemical staining, immunofluorescence, and Western blot techniques. Additionally, proliferation assays were conducted on primary rat pulmonary artery smooth muscle cells (PASMCs). We identified forty-two differentially expressed genes that exhibited either hypermethylated or hypomethylated m6A. These genes are predominantly related to the extracellular matrix structure, MAPK, and PI3K/AKT pathways. A candidate gene, centromere protein F (CENPF), was detected with increased expression in the PAH group. Additionally, we first identified an m6A reader, leucine rich pentatricopeptide repeat containing (LRPPRC), which was downregulated in the PAH rat model. The in vitro downregulation of Lrpprc mediated by siRNA resulted in the enhanced proliferation and elevated expression of Cenpf mRNA in primary rat PASMCs. Our study revealed a modified transcriptome-wide m6A landscape and associated regulatory mechanisms in the pulmonary arteries of PAH rats, potentially offering a novel target for therapeutic strategies in the future.

lncRNA ZEB1-AS1 Mediates Oxidative Low-Density Lipoprotein-Mediated Endothelial Cells Injury by Post-transcriptional Stabilization of NOD2

Oxidized-low density lipoprotein (ox-LDL) can induce injury of endothelial cells, causing atherosclerosis, which is an important initial event in several cardiovascular diseases. Long non-coding RNAs (lncRNAs) have emerged as regulators of diverse biological processes, but their specific biological functions and biochemical mechanisms in ox-LDL-induced endothelial cell injury have not been well investigated. Here, we describe the initial functional analysis of a poorly characterized human lncRNA ZEB1 antisense 1 (ZEB1-AS1). We found that ox-LDL treatment could induce a decreased cell viability and an increased cell apoptosis in endothelial cells, and knockdown of ZEB1-AS1 significantly reversed this effect. Mechanistically, ox-LDL treatment could sequester p53 from binding to ZEB1-AS1 promoter region, causing transcriptional activation and upregulation of ZEB1-AS1. Moreover, enhanced ZEB1-AS1 could upregulate Nucleotide-Binding Oligomerization Domain 2 (NOD2) expression through recruiting leucine-rich pentatricopeptide repeat motif-containing protein (LRPPRC) to stabilize NOD2 mRNA. Experimental data showed that knockdown of NOD2 or LRPPRC dramatically abrogated the functional role of ZEB1-AS1 in ox-LDL-induced endothelial cell injury. In summary, we demonstrated that lncRNA ZEB1-AS1 regulates the ox-LDL-induced endothelial cell injury via an LRPPRC-dependent mRNA stabilization mechanism. Therefore, ZEB1-AS1 may serve as a multi-potency target to overcome endothelial cell injury, atherosclerosis and other cardiovascular diseases.