A novel circ_0018553 protects against angiotensin-induced cardiac hypertrophy in cardiomyocytes by modulating the miR-4731/SIRT2 signaling pathway.

Due to the complicated pathophysiology of cardiac hypertrophy, there are no effective therapies for the treatment of pathological cardiac hypertrophy. Accumulating evidence has demonstrated that circRNAs participate in the pathophysiology of cardiac hypertrophy. In this study, we investigated the regulatory mechanisms of the novel circ_0018553 in angiotensin II (Ang II)-induced cardiac hypertrophy. Circ_0018553 was enriched in endothelial progenitor cell (EPC)-derived exosomes, and circ_0018553 expression was downregulated in a cellular model of Ang II-induced cardiac hypertrophy. Silencing circ_0018553 promoted cardiac hypertrophy in the Ang II-induced cardiac hypertrophy cellular model, while overexpression of circ_0018553 significantly attenuated Ang II-induced cardiac hypertrophy in cardiomyocytes. Moreover, mechanistic studies revealed that circ_0018553 acted as a sponge for miR-4731 and that miR-4731 repressed sirtuin 2 (SIRT2) expression by targeting the 3'UTR of SIRT2. MiR-4731 overexpression promoted cardiac hypertrophy in the Ang II-induced cardiac hypertrophy cellular model, while inhibition of miR-4731 significantly attenuated Ang II-induced cardiac hypertrophy in cardiomyocytes. The rescue experiments showed that miR-4731 overexpression attenuated the protective effects of circ_0018553 overexpression on the cardiac hypertrophy induced by Ang II; SIRT2 silencing also attenuated the protective effects of miR-4731 inhibition on the Ang II-induced cardiac hypertrophy. In conclusion, our results indicated that EPC-derived exosomal circ_0018553 protected against Ang II-induced cardiac hypertrophy by modulating the miR-4731/SIRT2 signaling pathway.

The potential role of circulating exosomes in protecting myocardial injury in acute myocardial infarction via regulating miR-190a-3p/CXCR4/CXCL12 pathway.

Exosomes of different origins have been found to be protective against ischemic-induced myocardial injury. This study examined the protective effects of circulating exosomes in the mice model of acute myocardial infarction (AMI) and explored the underlying molecular mechanisms. The effects of exosomes on myocardial injury were assessed in the AMI mice model. The in vivo studies showed that circulating exosomes reduced the infarcted size, improved the morphology of heart tissues and also reduced apoptosis of the heart tissues. In addition, the model mice showed an increase in the CD34 + /VEGFR2 + cell population and CD31, CXCR4 and CXCL12 expression after exosomes treatment. MiR-190a-3p was significantly down-regulated in the exosomes derived from the culture medium of hypoxia-treated human cardiomyocytes (HCMs). Further analysis revealed that miR-190a-3p could physically interact with CXCR4/CXCL12 by targeting the respective 3'UTRs. These exosomes could up-regulated CXCR4 and CXCL12 expression in the EPCs; in addition, miR-190a-3p mimics repressed CXCR4/CXCL12 expression in EPCs, while its inhibitor had opposite effects. The in vitro functional assays showed that miR-190a-3p overexpression suppressed the cell viability, proliferation, migration, adhesion and tube formation of EPCs; while miR-190a-3p inhibitor had the opposite effects; exosomes derived from the culture medium of hypoxia-treated HCMs exhibited similar actions of miR-190a-3p inhibitor. Moreover, miR-190a-3p was down-regulated in exosomes from serum in the AMI group when compared to that from sham group. Treatment with exosomes from serum in the AMI group promoted cell proliferation, migration, adhesion and tube formation of EPCs when compared to that in the sham group. More importantly, IT1t attenuated the enhanced effects of miR-190a-3p inhibition on EPC proliferation, migration, adhesion and tube formation. In conclusion, circulating exosomes exerted protective effects on myocardial injury in the AMI mice model, and down-regulation of miR-190a-3p in the circulating exosomes may exert protective effects against myocardial injury. Hypoxia induced the downregulation of miR-190a-3p in the culture medium of HCMs, and the mechanistic investigations indicated that exosomes of hypoxia-conditioned HCM culture medium promoted the cell viability, proliferation, migration, adhesion and tube formation of EPCs via regulating miR-190a-3p/CXCR4/CXCL12 pathway.

Exogenous H2S reverses high glucose-induced endothelial progenitor cells dysfunction via regulating autophagy.

This study aims to determine the effect of exogenous hydrogen sulfide (H2S) under high glucose (HG)-induced injury in endothelial progenitor cells (EPCs), and to explore the possible underlying mechanisms. Mononuclear cells were isolated from the peripheral blood of healthy volunteers by density-gradient centrifugation and identified as late EPCs by immunofluorescence and flow cytometry. EPCs were treated with high concentrations of glucose, H2S, Baf-A1, 3-MA or rapamycin. Cell proliferation, cell migration and tube formation were measured using cell counting kit-8, Transwell migration and tube formation assays, respectively. Cellular autophagy flux was detected by RFP-GFP-LC3, and Western blotting was used to examine the protein expression levels of LC3B, P62, and phosphorylated endothelial nitric oxide synthase (eNOS) at Thr495 (p-eNOSThr495). Reactive oxygen species (ROS) levels were measured using a DHE probe. H2S and rapamycin significantly reversed the inhibitory effects of HG on the proliferation, migration, and tube formation of EPCs. Moreover, H2S and rapamycin led to an increase in the number of autophagosomes accompanied by a failure in lysosomal turnover of LC3-II or p62 and p-eNOSThr495 expression and ROS production under the HG condition. However, Baf-A1 and 3-MA reversed the effects of H2S on cell behavior. Collectively, exogenous H2S ameliorated HG-induced EPC dysfunction by promoting autophagic flux and decreasing ROS production by phosphorylating eNOSThr495.

Development of a multi-arm polyrotaxanes modified mesoporous silica-coated gold nanoplatform for protecting endothelial progenitor cells against high glucose environment.

Recent study reported that endothelial progenitor cells (EPCs) have potential to treat diabetic macroangiopathy. High glucose environment of diabetes can affect the adhesion of EPCs by decreasing the expression of CXC chemokine receptor 4 (CXCR4) and affect the proliferation of EPCs by decreasing the expression of miR-126. The results showed that the cytotoxicity of GNR@MSNs@PEI to EPCs was significantly lower than PEI; the temperature of GNR@MSNs@PEI solution can be controlled between 38-40°C under 808 nm laser irradiation. 25.67 µg of pcDNA3.1-GFP-CXCR4 and 5.36 µg of FITC-miR-126 could be loaded in 1 mg of GNR@MSNs@PEI; GNR@MSNs@PEI has gene transfection almost the same as Lipofectamine 3000. Subsequent in vitro studies showed that pcDNA3.1-GFP-CXCR4 and miR-126 loaded GNR@MSNs@PEI can significantly increase the adhesion and proliferation and decrease the apoptosis of EPCs treated with high glucose under 808 nm laser irradiation. In conclusion, nano-carriers (GNR@MSNs@PEI) with high pcDNA3.1-CXCR4 and miR-126 loading capacity, high biocompatibility, well cell internalization, and controllable release ability were constructed to transfer CXCR4 expression plasmid (pcDNA3.1-CXCR4) and miR-126 into EPCs efficiently. Further in vitro studies indicated that pcDNA3.1-CXCR4 and miR-126-loaded GNR@MSNs@PEI could protect EPCs against high glucose-induced injury.

Emodin inhibits viability, proliferation and promotes apoptosis of hypoxic human pulmonary artery smooth muscle cells via targeting miR-244-5p/DEGS1 axis.

OBJECTIVE: This study aimed to determine the effects of emodin on the viability, proliferation and apoptosis of human pulmonary artery smooth muscle cells (PASMCs) under hypoxia and to explore the underling molecular mechanisms. METHODS: PASMCs were cultured in a hypoxic environment (1% oxygen) and then treated with emodin. Cell viability, proliferation and apoptosis were evaluated using CCK-8 assay, EdU staining assay, western blot and Mito-tracker red CMXRos and Annexin V-FITC apoptosis detection assay. The microRNA (miRNA)/mRNA and protein expression levels were assessed by quantitative real-time PCR and western blotting, respectively. Based on transcriptomics and proteomics were used to identify potential signaling pathways. Luciferase reporter assay was utilized to examine the interaction between miR-244-5p and DEGS1. RESULTS: Emodin at 40 and 160 µM concentration-dependently suppressed cell viability, proliferation and migration, but enhanced cell apoptosis of PASMCs under hypoxia. Transcriptomic and proteomic analysis revealed that emodin could attenuate the activity of PI3K/Akt signaling in PASMCs under hypoxia. In addition, delta 4-desaturase, sphingolipid 1 (DEGS1) was found to be a direct target of miR-244-5p. Emodin could significantly up-regulated miR-244-5p expression and down-regulated DEGS1 expression in PASMCs under hypoxia. Furthermore, emodin-mediated effects on cell viability, migration, apoptosis and PI3K/Akt signaling activity of PASMCs under hypoxia were significantly attenuated by miR-244-5p knockdown. CONCLUSIONS: Our results indicated that emodin suppressed cell viability, proliferation and migration, promoted cell apoptosis of PASMCs under hypoxia via modulating miR-244-5p-mediated DEGS1/PI3K/Akt signaling pathway. MiR-244-5p/DEGS1 axis was initially investigated in this current study, which is expected to further the understanding of the etiology of pulmonary arterial hypertension.

[Outcomes of percutaneous coronary intervention for intermediate coronary artery disease guided by intravascular ultrasound or fractional flow reserve].

OBJECTIVE: To evaluate the long-term clinical outcomes of fractional flow reserve (FFR)-guided versus intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) for intermediate coronary lesions. METHODS: A total of 226 patients with 293 intermediate coronary artery lesions (stenosis of 40%-70%) confirmed by coronary angiography were randomized into 3 groups to undergo PCI for a minimal lumen cross sectional area (MLA)<4 mm(2) (IVUS group, 98 lesions) or for a FFR<0.80 (FFR group, 101 lesions), or to receive standard medical treatment (medication group, 94 lesions). The primary outcome was major adverse cardiac events including death, myocardial infarction, and ischemia-driven target vessel revascularization at 1 year after the index procedure. RESULTS: The baseline percent diameter stenosis and lesion length were similar between the 3 groups, but more patients in IVUS group than in FFR group received PCI (P<0.001). No significant difference was found in the incidence of major adverse cardiac events between the 3 groups (P=0.182). CONCLUSION: Both FFR- and IVUS-guided PCI strategy for intermediate coronary artery disease are associated with favorable outcomes, but IVUS-guided PCI based on the single index of MLA can increase the rate of revascularization therapy.

[Urotensin II induces hypertrophy of in vitro cultured neonatal rat cardiac myocytes].

OBJECTIVE: To examine whether urotensinII (UII) induces hypertrophy of neonatal rat cardiomyocytes cultured in vitro. METHODS: The primary cardiac myocytes cultured for 40 h followed by further culture in serum-free media for another 24 h were subjected to exposure to UII of varied concentrations for 24 h, after which the changes in the size of the cells were analyzed by flow cytometry with (3)H-leucine incorporation also measured. RESULTS: At the concentration of 1x10(-7) mol/L, UIIcould increase the size of the cultured cardiac myocardial cells (P=0.021) and 3H-Leucine incorporation (P=0.015). CONCLUSION: UII may induce hypertrophy of neonatal rat cardiac myocytes cultured in vitro.

[Effects of urotensin II on cultured cardiac fibroblast proliferation and collagen type I mRNA expression].

OBJECTIVE: To observe the effect of urotensin II on cultured cardiac fibroblast collagen type I mRNA expression and proliferation, thereby to explore the role of urotensin II in myocardial remodeling in the event of cardiac failure. METHODS: Cardiac fibroblasts of neonatal Sprague-Dawley rats isolated by trypsin digestion method were stimulated by urotensin II at varied concentrations when the cells reached growth arrest. MTT assay was employed to measure the proliferation and determine the number of the cells, and reverse transcriptional (RT)-PCR used to detect the collagen mRNA expression. RESULTS: With the increase of urotensin II concentration, the optical density at 570 nm of the fibroblasts as shown by MTT assay first increased but then decreased, and remained at a significantly higher level in the cells treated with 1x10(-8) or 1x10(-9) mol/L urotensin II as compared with the control (P<0.05). The collagen type I mRNA levels of the cells treated with 1x10(-7), 1x10(-8) or 1x10(-9) mol/L urotensin II were significantly higher than that of the control cells (P<0.01). CONCLUSION: Urotensin II can directly induce cardiac fibroblast proliferation and significantly increase collagen type I mRNA expression, suggesting the crucial role of urotensin II in myocardial remodeling.