Identification of a novel regulatory pathway for PPARα by RNA-seq characterization of the endothelial cell lipid peroxidative injury transcriptome

Abstract

Endothelial dysfunction caused by endothelial cell injuries is the initiating factor for atherosclerosis (AS), and lipid peroxidative injury is one of a dominant factor for AS pathogenesis. Using RNA-seq, we compared changes in transcriptome expression before and after endothelial cell injury, and found 311 differentially expressed genes (DEGs), of which 258 genes were upregulated and 53 genes were downregulated. The protein–protein interactions (PPIs) between the genes were analysed using the STRING database, and a PPI network of DEGs was constructed. The relationship distributions among these PPIs were analysed by performing network node statistics. We found that in the top 20 DEGs with high connected protein nodes in the PPI network, 16 were upregulated and 4 were downregulated. Gene ontology (GO) functional enrichment analysis and KEGG pathway enrichment analysis on the DEGs were also performed. By comparing the upregulated expressed genes with high connected protein nodes in the PPI network to those related to endothelial cell lipid damage and repair in the GO analysis, we identified seven genes (NOX4, PPARA, CCL2, PDGFB, IL8, VWF, CD36) and verified their expression levels by real-time polymerase chain reaction. The protein interactions between the seven genes were then analysed using the STRING database. The results predicted that CCL2 interacts with NOX4, PPARα, PDGFβ and VWF individually. Thus, we examined the protein expression levels of CCL2, NOX4, PPARα, PDGFβ and VWF, and found that the expression levels of all proteins were significantly upregulated after the lipid peroxidative injury, with CCL2 and PPARα exhibiting the highest expression levels. Therefore, we investigated the interregulatory relationship between CCL2 and PPARα and their roles in the repair of endothelial cell injury. With the help of gene overexpression and knockdown techniques, we discovered that PPARα promotes the repair of endothelial cell injury by upregulating CCL2 expression in human umbilical vein endothelial cells but that CCL2 cannot regulate PPARα expression. Therefore, we believe that PPARα participates in the repair of endothelial cell lipid peroxidative injury through regulating the expression of CCL2.

PPARα Targeting GDF11 Inhibits Vascular Endothelial Cell Senescence in an Atherosclerosis Model

“…Clinical experiments have found significantly reduced levels of plasma interleukin-6 (IL-6), interferon- α (IFN- α ), and C-reactive protein (CRP) after taking the PPAR α agonist (fibrate) in patients with coronary heart disease confirmed by angiography [ 14 ]. Our previous research confirmed that PPAR α promotes the repair of endothelial cell injury by upregulating CCL2 expression in human umbilical vein endothelial cells [ 15 ]. Some research reported that Tongxinluo protects diabetic hearts against ischemia/reperfusion injury by activating Angptl4-mediated restoration of endothelial barrier integrity via the PPAR α pathway [ 16 ].…”

“…Some research reported that PPAR γ protects against vascular aging [ 27 ], but there were few studies on the correlation between PPAR α and aging. Our previous RNA sequence research found that PPAR α was involved in the regulation of damaged vascular endothelial cell repair [ 15 ]. The causes of endothelial cell aging mainly include cell replication aging and stress-induced cell premature senility.…”

Molecular mechanisms and therapeutic perspectives of peroxisome proliferator‐activated receptor α agonists in cardiovascular health and disease

“…In addition, lipid peroxidation mediated by endogenous factors, such as NADPH oxidases, reactive oxygen species, lipoxygenases and xanthine oxidase, and exogenous reagents, such as cigarette smoking, UV‐light, and air pollution, results in more oxidized lipids (e.g., oxidized LDL) to produce pro‐inflammatory effects on endothelium and macrophages 59 . PPARα overexpression accelerates endothelial repair after lipid peroxidative‐induced injury in a C─C motif chemokine ligand 2‐dependent mechanism 60 …”

“…59 PPARα overexpression accelerates endothelial repair after lipid peroxidative-induced injury in a C─C motif chemokine ligand 2-dependent mechanism. 60 Insulin resistance is an important risk factor of endothelial activation, which is defined as a lack of sensitivity or responsiveness to insulin-mediated actions such as glucose disposal and vascular tone regulation. 61 Insulin resistance is a prominent element of obesity and type 2 diabetes, where both are associated with endothelial dysfunction.…”

Transcriptome analyses profiles of dietary l‐alanyl‐l‐glutamine supplementation in Amur sturgeon, Acipenser schrenckii, liver

“…A transcriptome is all the transcripts produced in cells under specific physiological conditions and reveals the molecular mechanism of specific biological processes (Dou et al, 2019). High-throughput mRNA sequencing (RNA-Seq), an ultrahigh-throughput sequencing technology for transcriptomic analysis, has been widely used to reveal the gene expression changes of non-model organisms that lack reference genome information (Grabherr et al, 2011).…”