Background/Aims: Endothelial-to-mesenchymal transition (EndMT) plays significant roles under various pathological conditions including cardiovascular diseases, fibrosis, and cancer. EndMT of endothelial progenitor cells (EPCs) contributes to neointimal hyperplasia following cell therapy Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA (lncRNA) that promotes metastasis and cancer. MicroRNA-145 (miR-145) is a tumor suppressor that has been reported to inhibit SMAD3-mediated epithelial-to-mesenchymal transition (EMT) of cancer cells. In the present study, we investigated the role of MALAT1 and miR-145 in EndMT of human circulating EPCs induced by transforming growth factor beta1 (TGF-β1). Methods: Human circulating EPCs were isolated and characterized by fluorescence-activated cell sorting (FACS). Expression levels of EndMT markers were assessed by qRT-PCR and western blotting. Alpha-smooth muscle actin (α-SMA) expression was measured by cell immunofluorescence staining. The regulatory relationship between MALAT1 and miR-145 and its target genes, TGFBR2 (TGFβ receptortype II) and SMAD3 (mothers against decapentaplegic homolog 3) was analyzed using the luciferase reporter assay. Results: We found that EndMT of EPCs induced by TGF-β1 is accompanied by increased MALAT1 expression and decreased miR-145 expression, and MALAT1 and miR-145 directly bind and reciprocally repress each other in these cells. Dual-Luciferase Reporter assay indicated that miR-145 inhibits TGF-β1-induced EndMT by directly targeting TGFBR2 and SMAD3. Conclusions: MALAT1 modulates TGF-β1-induced EndMT of EPCs through regulation of TGFBR2 and SMAD3 via miR-145. Thus, the MALAT1-miR-145-TGFBR2/SMAD3 signaling pathway plays a key role in TGF-β1-induced EndMT.

Edited by Tamas DalmayKeywords: CXCR2 miRNA-22-3p MALAT1 Endothelial cells ox-LDL a b s t r a c t CXCR2 plays a key role in protecting the integrity of the endothelium. Emerging evidence has demonstrated that the long ncRNAs (lncRNA) Human metastasis associated lung adenocarcinoma transcript 1 (MALAT1) participates in the regulation of the pathophysiological processes. However, whether there is crosstalk between CXCR2 and MALAT1 remains unknown. In this study, we demonstrated that MALAT1 was upregulated in patients with unstable angina. MALAT1 silencing significantly downregulated the expression of the miR-22-3p target gene CXCR2 via reversing the effect of the miR-22-3p, resulting in the aggravation of Oxidized low-density lipoprotein (ox-LDL)-induced endothelial injury; this process was associated with the AKT pathway. Thus, MALAT1 protects the endothelium from ox-LDL-induced endothelial dysfunction partly through competing with miR-22-3p for endogenous RNA.

The biological effects of microRNAs (miRNAs) and TNF-α in atherosclerosis have been widely studied. The circulating miR-17-92 cluster has been recently shown to be significantly downregulated in patients with injured vascular endothelium. However, it remains unclear whether the miR-17-92 cluster plays a significant role in vascular endothelial repair. The aim of this study was to investigate the relationship between the miR-17-92 cluster and TNF-α-induced endothelial cell apoptosis. We determined that the down-regulation of miR-19b level among patients with coronary artery disease was consistent with miRNA expression changes in endothelial cells following 24 h of TNF-α treatment. In vitro, the overexpression of miR-19b significantly alleviated the endothelial cells apoptosis, whereas the inhibition of miR-19b significantly enhanced apoptosis. The increased levels of Afap1 and caspase7 observed in our apoptosis model could be reduced by miR-19b, and this effect could be due to miR-19b binding 3′-UTRs of Afap1 and caspase7 mRNA. Therefore our results indicate that miR-19b plays a key role in the attenuation of TNF-α-induced endothelial cell apoptosis and that this function is closely linked to the Apaf1/caspase-dependent pathway.

Background/Aims: Excessive reactive oxygen species (ROS) disturb the physiology of H9c2 cells, which is regarded as a major cause of H9c2 cardiomyocyte apoptosis. Ginsenoside Rg1 is the main active extract of ginseng, which has important antioxidant properties in various cell models. This project investigated the role of ginsenoside Rg1 in hypoxia/reoxygenation (H/R)-induced oxidative stress injury in cultured H9c2 cells to reveal the underlying signaling pathways. Methods: H9c2 cells were pretreated with ginsenoside Rg1 for 12 h before exposure to H/R. In the absence or presence of Nrf2siRNA, HO-1 inhibitor (ZnPP-IX), and inhibitors of the MAPK pathway (SB203580, PD98059, SP600125), H9c2 cells were subjected to H/R with Rg1 treatment. The effects and mechanisms of H/R-induced cardiomyocyte injury were measured. Results: Ginsenoside Rg1 treatment suppressed H/R-induced apoptosis and caspase-3 activation. Ginsenoside Rg1 treatment decreased ROS production and mitochondrial membrane depolarization by elevating the intracellular antioxidant capacity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and reduced glutathione (GSH). Furthermore, ginsenoside Rg1 stimulation appeared to result in nuclear translocation of NF-E2-related factor 2 (Nrf2), along with enhanced expression of the downstream target gene heme oxygenase-1 (HO-1) in a dose-dependent manner. However, ginsenoside Rg1-mediated cardioprotection was abolished by Nrf2-siRNA and HO-1 inhibitor. H/R treatment increased the levels of phosphorylated c-Jun N-terminal kinases (p-JNK), which was dramatically attenuated by ginsenoside Rg1 and SP600125 (a specific JNK inhibitor). Conclusion: These observations indicate that ginsenoside Rg1 activates the Nrf2/HO-1 axis and inhibits the JNK pathway in H9c2 cells to protect against oxidative stress.

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The relationship between oxidized low-density lipoprotein (Ox-LDL) and C-reactive protein (CRP) in patients with acute coronary syndrome (ACS) is unknown. We, therefore, measured serum levels of Ox-LDL and high-sensitivity (hs)-CRP in 90 ACS patients, 45 stable angina pectoris (SAP) patients, and 66 healthy controls using sandwich ELISA. ACS patients were subdivided into: (1) acute myocardial infarction (AMI; n = 45); (2) unstable angina pectoris (UAP; n = 45) groups. In AMI patients, Ox-LDL (177.5 mmol/l) and hs-CRP (25.40 mg/l) levels were significantly higher (P < 0.01) than in UAP (Ox-LDL:107.5 mmol/l, hs-CRP:10.7 mg/l) and SAP (Ox-LDL:82.3 mmol/l, hs-CRP:2.10 mg/l) patients as well as controls (Ox-LDL:41.4 mmol/l, hs-CRP:1.76 mg/l). Ox-LDL/hs-CRP levels in UAP patients were significantly higher (P < 0.01) than in SAP patients and controls. Importantly, a positive correlation was found between Ox-LDL and CRP (r = 0.622; P < 0.01) levels. Serum levels of total, HDL, and LDL cholesterol did not differ among these patient groups. In conclusion, our data show that Ox-LDL and hs-CRP levels correlate positively in ACS patients, supporting the hypothesis that Ox-LDL and CRP may play a direct role in promoting the inflammatory component of atherosclerosis in these individuals. We suggest that Ox-LDL/CRP elevated levels may serve as markers of the severity of the disease in evaluation and management of ACS patients.

Coronary artery disease is a major cause of morbidity and mortality worldwide. Impaired endothelial function and integrity are major contributory factors to coronary artery disease. MicroRNAs have been proposed to play an important role in coronary artery disease pathogenesis. In the present study, the expression of miR‐206 was found to be significantly upregulated in peripheral blood endothelial progenitor cells from patients with coronary artery disease compared to healthy donors. MiR‐206 was found to regulate endothelial progenitor cell activities by targeting the protein kinase PIK3C2α, which showed decreased expression in coronary artery disease endothelial progenitor cells. Knockdown of miR‐206 in coronary artery disease endothelial progenitor cells rescued their angiogenic and vasculogenic abilities both in vitro and in vivo in a mouse ischemic hindlimb model. Furthermore, knockdown of miR‐206 activated not only PIK3C2α, but also the angiogenic signal modulators Akt and endothelial nitric oxide synthase. It is therefore proposed that repression of the phosphoinositide 3‐kinase/Akt/endothelial nitric oxide synthase signal transduction pathway by miR‐206 downregulates angiogenesis contributing to the pathophysiology of coronary artery disease.

SMI can improve not only the endothelial function in CHD-DM patients, but also heart contraction significantly.