Role of Nucleotide-binding and Oligomerization Domain 2 Protein (NOD2) in the Development of Atherosclerosis

Circular RNA circ_0008896 contributes to oxidized low-density lipoprotein-induced aortic endothelial cell injury via targeting miR-188-3p/NOD2 axis

We aimed to investigate the role and mechanism of circ_0008896 in Atherosclerosis (AS) by using oxidized low-density lipoprotein (ox-LDL)-induced human aortic endothelial cell (HAECs). Levels of genes and proteins were measured by quantitative real-time PCR and Western blot. Functional experiments, including enzyme-linked immunosorbent assay analysis, cell counting kit-8, 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, tube formation assays and the detection of reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) generation, were performed to investigate the role of circ_0008896 on ox-LDL-induced HAEC damage. Circ_0008896 was increased in AS patients and ox-LDL-stimulated HAECs. Functionally, circ_0008896 knockdown reversed ox-LDL-induced inflammatory response, oxidative stress, apoptosis as well as arrest of proliferation and angiogenesis in HAECs in vitro. Mechanistically, circ_0008896 functioned as a sponge for miR-188-3p to relieve the repression of miR-188-3p on its target NOD2. A series of rescue experiments showed that miR-188-3p inhibition attenuated the protective effects of circ_0008896 knockdown on ox-LDL-stimulated HAECs, and NOD2 overexpression abolished the beneficial action of miR-188-3p in the suppression of inflammatory response and oxidative stress, and the promotion of cell growth and angiogenesis in HAECs under ox-LDL treatment. Circ_0008896 silencing attenuates ox-LDL-induced inflammatory response, oxidative stress, and growth arrest in HAECs in vitro, adding further understanding for the pathogenesis of AS.

Blood-Brain Barrier Integrity Damage in Bacterial Meningitis: The Underlying Link, Mechanisms, and Therapeutic Targets

Despite advances in supportive care and antimicrobial treatment, bacterial meningitis remains the most serious infection of the central nervous system (CNS) that poses a serious risk to life. This clinical dilemma is largely due to our insufficient knowledge of the pathology behind this disease. By controlling the entry of molecules into the CNS microenvironment, the blood-brain barrier (BBB), a highly selective cellular monolayer that is specific to the CNS's microvasculature, regulates communication between the CNS and the rest of the body. A defining feature of the pathogenesis of bacterial meningitis is the increase in BBB permeability. So far, several contributing factors for BBB disruption have been reported, including direct cellular damage brought on by bacterial virulence factors, as well as host-specific proteins or inflammatory pathways being activated. Recent studies have demonstrated that targeting pathological factors contributing to enhanced BBB permeability is an effective therapeutic complement to antimicrobial therapy for treating bacterial meningitis. Hence, understanding how these meningitis-causing pathogens affect the BBB permeability will provide novel perspectives for investigating bacterial meningitis's pathogenesis, prevention, and therapies. Here, we summarized the recent research progress on meningitis-causing pathogens disrupting the barrier function of BBB. This review provides handy information on BBB disruption by meningitis-causing pathogens, and helps design future research as well as develop potential combination therapies.

Atherosclerosis prediction by microarray-based DNA methylation analysis

Using a series of DNA methylation analysis, pathogenesis was investigated to identify the specific DNA methylation markers for diagnosing atherosclerosis. Firstly, with the chip platform of Illumina Human Methylation 450 BeadChip, a total of 1,458 CpGs, covering 971 differential methylated genes were extracted with stringent filtering criteria. Secondly, hierarchical clustering as a heat map was used to check on the dependability of differential methylated genes. Thirdly, the related GO terms and pathways were enriched by up- and down-methylated genes, respectively, after verifying the capacity of these differential methylated genes to distinguish between atherosclerosis and healthy controls. In total, 971 differential DNA methylated genes were identified (1,458 CpGs). Several important function regions were also identified, including cell adhesion, PI3K-Akt signaling pathway and transcription from RNA polymerase II promoter. This study indicates that patients with atherosclerosis have high levels of DNA methylation, which is promising for early diagnosis and treatment of atherosclerosis.

Research Progress of Mechanisms and Drug Therapy For Atherosclerosis on Toll-Like Receptor Pathway

Recent reports have established atherosclerosis (AS) as a major factor in the pathogenetic process of cardiovascular diseases such as ischemic stroke and coronary heart disease. Although the possible pathogenesis of AS remains to be elucidated, a large number of investigations strongly suggest that the inhibition of toll-like receptors (TLRs) alleviates the severity of AS to some extent by suppressing vascular inflammation and the formation of atherosclerotic plaques. As pattern recognition receptors, TLRs occupy a vital position in innate immunity, mediating various signaling pathways in infective and sterile inflammation. This review summarizes the available data on the research progress of AS and the latest antiatherosclerotic drugs associated with TLR pathway.

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.

Adipose differentiation‑related protein knockdown inhibits vascular smooth muscle cell proliferation and migration and attenuates neointima formation

Vascular smooth muscle cells (VSMCs) have an important role in atherosclerosis development. Evidence has demonstrated that adipose differentiation-related protein (ADRP) is associated with foam cell formation and atherosclerosis progression. However, to the best of our knowledge, no previous studies have investigated the role of ADRP knockdown in platelet-derived growth factor (PDGF)-stimulated proliferation and migration of VSMCs in vitro. Furthermore, the effect of ADRP knockdown on neointima formation in vivo remains unclear. In the present study, primary human aortic VSMCs were incubated with PDGF following ADRP small interfering (si)RNA transfection. Cell viability, migration and cell cycle distribution were analyzed by MTT, wound healing and Transwell assays and flow cytometry, respectively. Extracellular signal-regulated kinase (ERK), phosphorylated (p)-ERK, Akt, p-Akt, proliferating cell nuclear antigen (PCNA), matrix metalloproteinase (MMP)-2 and MMP-9 protein levels were determined by western blotting. Apolipoprotein E^−/− mice fed an atherogenic diet were injected with siADRP or control siRNA twice a week. After 3 weeks of therapy, aortas were excised and ADRP mRNA and protein expression was determined. Neointima formation was assessed by hematoxylin and eosin staining. The results of the current study demonstrated that ADRP knockdown significantly inhibited PDGF-induced increases in VSMC viability, caused G1 phase cell cycle arrest and decreased PCNA expression. Knockdown of ADRP inhibited PDGF-induced migration of VSMCs by reducing MMP protein expression and activity. In addition, the present study also demonstrated that ADRP knockdown inhibited ERK and Akt signaling pathways in response to PDGF. Furthermore, siADRP administration suppressed neointima formation in the mouse model. The results of the present study indicate that ADRP may be a potential target for the treatment of atherosclerosis.