Zhixing Fan

MicroRNA-24 inhibits high glucose-induced vascular smooth muscle cell proliferation and migration by targeting HMGB1.

Dysfunction of vascular smooth muscle cells (VSMCs) performs a key role in the pathogenesis of diabetic vascular disease. Recent studies have reported that microRNA-24 (miR-24) may be implicated in diabetes and atherosclerotic vascular diseases. This study was designed to explore the role of miR-24 on VSMC proliferation and migration under high glucose conditions mimicking diabetes, and reveal the underlying mechanism. VSMCs were isolated from rat thoracic aortas, treated with normal glucose (NG, 5.5mM) or high glucose (HG, 30mM) during an incubation period. Cell viability, proliferation and migration were detected by trypan blue staining, BrdU incorporation assay and transwell chamber assay. Gene and protein expression were analyzed by qRT-PCR and Western blot respectively. We also used electrophoretic mobility shift assay (EMSA) to detect nuclear factor kappaB (NF-κB) DNA binding. TNF-α and IL-6 levels were determined by enzyme-linked immunosorbent assay. The results showed that adenovirus-mediated miR-24 overexpression significantly inhibited HG-stimulated VSMC proliferation and migration. Meanwhile, high mobility group box-1 (HMGB1) as a target of miR-24, was also markedly suppressed after miR-24 transfection. Additionally, NF-κB nuclear translocation and DNA binding, TNF-α and IL-6 production were all decreased associated with the down-regulation of HMGB1. The above data indicated that miR-24 is a crucial regulator of high glucose-induced proliferation and migration in VSMCs, and suggests that elevation of miR-24 in vascular system may be a novel therapeutic strategy to prevent the development of diabetic atherosclerosis.

Cardioprotective effect of miRNA-22 on hypoxia/reoxygenation induced cardiomyocyte injury in neonatal rats

MicroRNAs (miRNAs) are implicated in the regulation of pathological and physiological processes in myocardial ischemia/reperfusion (MI/R). Recent studies have revealed that miR-22 might provide a potential cardioprotective effect on ischemic heart disease. However, the mechanism by which miR-22 prevents MI/R is still not fully clear. Here, we investigated the role of miR-22 in hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury. MI/R was simulated in neonatal rat cardiomyocytes with 2h hypoxia followed by 4h reoxygenation. Prior to H/R, cells were transfected by Ad-miR-22 or Ad-scramble. It was revealed that H/R dramatically increased the release of CK and LDH, accompanied by a downregulation of miR-22 expression. Overexpression of miR-22 attenuated cardiomyocyte apoptosis and miR-22 target gene CREB binding protein (CBP) protein level, as determined by flow cytometry analysis and Western blot respectively. We further identified that miR-22 significantly inhibited CBP-related transcriptional factor AP-1 DNA binding activity under H/R. In addition, miR-22 could efficiently change Bcl-2/Bax ratio, and suppress the production of pro-inflammatory cytokines (TNF-α and IL-6) induced by H/R. In conclusion, these results suggest that miR-22 plays an important cardioprotective role partly via regulating CBP/AP-1 pathway to reduce cell apoptosis and inflammatory damage during MI/R injury.

microRNA‑22 attenuates myocardial ischemia‑reperfusion injury via an anti‑inflammatory mechanism in rats

Previous studies have reported that microRNA-22 (miR-22) may be implicated in ischemia-reperfusion (I/R)-induced myocardial injury. Our previously published data also demonstrated that miR-22 may protect against myocardial I/R injury via anti-apoptosis in rats by targeting cAMP response element-binding protein binding protein (CBP). However, the specific function of miR-22 in myocardial I/R injury is far from fully elucidated. The present study was designed to investigate another cardioprotective signaling mechanism of miR-22 in myocardial I/R injury. A total of 40 adult male Sprague-Dawley rats were randomly divided into four equal groups (n=10): Sham, myocardial I/R, myocardial I/R with adenovirus expressing scramble miRNA (Ad-Scramble) and myocardial I/R with adenovirus expressing miR-22 (Ad-miR-22) groups. Besides the Sham operation group, the remaining three groups were artificially afflicted with coronary occlusion for 30 min and subsequently reperfused for 4 h. A light microscope was used to observe structural changes in the myocardium; reverse transcription polymerase chain reaction was used to measure the miR-22 mRNA expression level; the myocardial infarct size was analyzed by the Evans Blue/triphenyltetrazolium chloride double-staining; and p38 mitogen-activated protein kinase (MAPK), CBP, c-Jun-activator protein (AP)-1 and phospho (p)-c-Jun-AP-1 expression protein levels were detected by a western blot. Furthermore, ELISA was used to measure the levels of TNF-α and IL-6 in the myocardium. The results demonstrated that adenovirus-mediated miR-22 overexpression markedly reduced p38 MAPK, CBP, c-Jun-AP-1, p-c-Jun-AP-1 expression levels concomitant with an improvement in myocardial injury, including smaller infarct size, reduced release of creatine kinase, lactate dehydrogenase and proinflammation mediators (tumor necrosis factor-α and interleukin-6). These findings suggest that miR-22 has a protective effect on myocardial I/R injury. This protection mechanism, at least in part, is due to its anti-inflammatory function via the suppression of the p38 MAPK/CBP/c-Jun-AP-1 signaling pathway.

MicroRNA-24 Attenuates Neointimal Hyperplasia in the Diabetic Rat Carotid Artery Injury Model by Inhibiting Wnt4 Signaling Pathway

The long-term stimulation of hyperglycemia greatly increases the incidence of vascular restenosis (RS) after angioplasty. Neointimal hyperplasia after vascular injury is the pathological cause of RS, but its mechanism has not been elucidated. MicroRNA-24 (miR-24) has low expression in the injured carotid arteries of diabetic rats. However, the role of miR-24 in the vascular system is unknown. In this study, we explore whether over-expression of miR-24 could attenuate neointimal formation in streptozotocin (STZ)-induced diabetic rats. Adenovirus (Ad-miR-24-GFP) was used to deliver the miR-24 gene to injured carotid arteries in diabetic rats. The level of neointimal hyperplasia was examined by hematoxylin-eosin (HE) staining. Vascular smooth muscle cell (VSMC) proliferation in the neointima was evaluated by immunostaining for proliferating cell nuclear antigen (PCNA). The mRNA levels of miR-24, PCNA, wingless-type MMTV integration site family member 4 (Wnt4), disheveled-1 (Dvl-1), β-catenin and cell cycle-associated molecules (Cyclin D1, p21) were determined by Quantitative Real-Time PCR (qRT-PCR). PCNA, Wnt4, Dvl-1, β-catenin, Cyclin D1 and p21 protein levels were measured by Western blotting analysis. STZ administration decreased plasma insulin and increased fasting blood glucose in Sprague-Dawley (SD) rats. The expression of miR-24 was decreased in the carotid artery after a balloon injury in diabetic rats, and adenoviral transfection (Ad-miR-24-GFP) increased the expression of miR-24. Over-expression of miR-24 suppressed VSMC proliferation and neointimal hyperplasia in diabetic rats at 14 days. Furthermore, compared with Sham group, the mRNA and protein levels of PCNA, Wnt4, Dvl-1, β-catenin, and Cyclin D1 were strikingly up-regulated in the carotid arteries of diabetic rats after a balloon injury. Interestingly, up-regulation of miR-24 significantly reduced the mRNA and protein levels of these above molecules. In contrast, the change trend in p21 mRNA and protein levels was opposite after a balloon injury. However, over-expression of miR-24 after gene delivery increased the mRNA and protein levels of p21. We conclude that over-expression of miR-24 could attenuate VSMC proliferation and neointimal hyperplasia after vascular injuries in diabetic rats. This result is possibly related to the regulation of the expression of Cyclin D1 and p21 through the Wnt4/Dvl-1/β-catenin signaling pathway.

Circular RNAs: Novel rising stars in cardiovascular disease research

Article history: Received 23 September 2015 Accepted 4 October 2015 Available online 9 October 2015 specific target messenger RNAs at the post-transcriptional level [7]. miRNAs play a significant role in regulating fundamental cellular processes (such as cell proliferation, differentiation, apoptosis, migration) and play critical roles in disease initiation and progression [8]. Numerous studies have confirmed that miRNAs are closely related to cardiovascular disease, which are potential emerging biomarkers with extreme sensitivity for early diagnosis and novel

IL-17: A promising therapeutic target for atherosclerosis.

Article history: Received 25 August 2015 Accepted 26 August 2015 Available online xxxx sclerosis, atheroprotective roles of IL-17 have also been reported [6,7]. IL-17 canmaintain the stability of plaque by increasing the proliferation of SMC and collagen content in thefibrous cap [6,7]. In addition, IL-17 also can reduce the expression of VCAM-1 on endothelial cells, which could inhibit inflammatory cell infiltration [7]. Similarly, some animal models and clinical researches also could demonstrate the atheroprotective role of IL-17. In a genetic invalidation model, IL-17A/Apoe DKO mice fed

A Meta-Analysis of Randomized Clinical Trials Comparing Shorter (Less or Equal Than 6 Months) and Longer (More or Equal Than 12 Months) Dual Anti-Platelet Therapy Following Drug-Eluting Coronary Stents.

Context: The optimal duration of dual anti-platelet therapy (DAPT) after the implantation of drug-eluting coronary stents (DES) is still the subject of ongoing debate. This meta-analysis was performed to investigate the optimal duration between ≤ 6 months and ≥ 12 months for DAPT after implantation of DES. Evidence Acquisition: This study was conducted at the department of cardiology, the first college of clinical medical sciences, institute of cardiovascular diseases of Three Gorges university during December 2014. Pub-med, Cochrane, Scopus and clinicaltrials.gov databases were searched for papers published until December 2014. Searches of the above databases included terms “dual anti-platelet therapy” and “myocardial infarction (MI)” and “drug-eluting stents (DES)”. All the searched literatures were limited to Randomized Controlled Trials (RCTs). Quality assessments were evaluated with the Jadad quality scale. Data were extracted by two independent observers (FZ and YC). For all analyses, the 95% confidence interval (CI) was calculated and heterogeneity of the studies was analyzed using I2 statistics. Results: Five RCTs with 9979 participants satisfying the inclusion criteria were finally analyzed. Overall, there were 4993 patients with shorter duration of DAPT and 4986 patients with a longer treatment. Clopidogrel was the used P2Y12 receptor inhibitor in all five RCTs. On one hand compared to shorter duration (≤ 12 months) DAPT, longer duration (≥ 12 months) did not reduce risk of mortality, cardiac death, cerebrovascular accidents, myocardial infarction and stent thrombosis (pooled OR 1.03, 95% Confidence Interval (CI) 0.80 - 1.32, P = 0.85, I2 = 0%; pooled OR 0.91, 95% CI 0.64 - 1.29, P = 0.60, I2 = 0%; pooled OR 0.84, 95% CI 0.50 - 1.42, P = 0.51, I2 = 0%; pooled OR 1.17, 95% CI 0.87 - 1.58, P = 0.29, I2 = 0%; pooled OR 1.36, 95% CI 0.81 - 2.29, P = 0.24, I2 = 0%). On the other hand, longer duration (≥ 12 months) could also increase the risk of thrombolysis in myocardial infarction (TIMI) major bleeding (pooled OR 0.50, 95% CI 0.29 - 0.85, P = 0.01, I2 = 0%). Conclusions: Regarding the efficacy outcomes of the patients after DES implantation, no differences were found between shorter (≤ 6 months) and longer (≥ 12 months) duration of DAPT. What is worse is that longer duration (≥ 12 months) was associated with increased risk of bleeding complications.

HDAC inhibition: A novel therapeutic approach for atherosclerosis

Article history: Received 4 September 2015 Accepted 24 September 2015 Available online 28 September 2015 early lesion of atherosclerosis [11]. Thirdly, HDACs regulatemacrophage foam cell and smooth muscle cell (SMC) foam cell formation [7]. There were two possible mechanisms for this role, regulating macrophage cholesterol reverse transport and increasing the up-taking of LDL and cholesterol. Fourthly, HDACs contribute to VSMC phenotype switch to a proliferation, migration and synthetic state and fibrous cap formation [7]. Fifthly, HDACs also play a role in plaque disruption and thrombosis

HMGB1: A promising therapeutic approach for atherosclerosis.

Article history: Received 3 September 2015 Accepted 24 September 2015 Available online 28 September 2015 the release of pro-inflammatory cytokines and induce harmful inflammatory responses by binding to its receptors (RAGE, TLR2, and TLR4) [6]. In a word, vascular inflammation plays a predominant role in the initiation, progression, and the final steps of atherosclerosis. So, the pro-inflammatory features of HMGB1might contribute to the formation of thrombus and progression of atherosclerosis. In recent years, HMGB1 has been increasingly studied for its roles in

DPP-4 inhibitors: A potential promising therapeutic target in prevention of atherosclerosis

Article history: Received 29 July 2015 Accepted 1 August 2015 Available online 5 August 2015 atherosclerosis. The underlying mechanisms of DPP-4 inhibitors protective roles in atherosclerosis are complicated and several reasons may contribute to it (Fig. 1). First of all, suppression of vascular smooth muscles cell (VSMC) has been considered to be the fundamental reason for DPP-4 inhibitors-mediated attenuation of atherosclerosis. Chois findings indicate that gemigliptin efficiently stimulated