Down-Regulation of miR-327 Alleviates Ischemia/Reperfusion-Induced Myocardial Damage by Targeting RP105.

BACKGROUND/AIMS: Micro RNAs (miRNAs) play a very important role in myocardial ischemia/ reperfusion injury (MIRI), including in inflammation, apoptosis, and angiogenesis. Previous studies have demonstrated up-regulation of miR-327 in renal ischemia/reperfusion injury and MIRI. Via TargetScan, we found RP105 is a possible target gene of miR-327; our previous studies have also confirmed that RP105 acted as a cardioprotective protein in MIRI by reducing inflammation. However, the regulatory effect of miR-327 on RP105 has not previously been proposed. In our study, we aimed to identify the regulatory effect of miR-327 on RP105 protein in MIRI rats. METHODS: Sixty male Sprague-Dawley rats were randomly divided into five groups, which were pre-treated with saline (sham and ischemia/reperfusion group), adenovirus-expressing miR-327-RNAi (Ad-miR-327-i group), control (Ad-NC group), or pri-miR-327 (Ad-miR-327 group) treatments. Three days later, the rat MIRI model was established by ischemia for 30 min, followed by reperfusion for 3 h. Myocardium and plasma were harvested and assessed. RESULTS: miR-327 was increased by nearly 3-fold both in myocardium and plasma, which down-regulated RP105 in a 3'-untranslated region-dependent manner, and down-regulation of miR-327 via adenovirus transfection indirectly suppressed the TLR4/ TLR2-MyD88-NF-κB signaling axis activation via up-regulation of RP105, which subsequently resulted in reduced myocardial infarct size, attenuated cardiomyocyte destruction, and alleviated inflammation. In contrast, up-regulation of miR-327 induced the opposite effect. CONCLUSION: Down-regulation of miR-327 exerts a cardioprotective effect against MIRI by reducing inflammation, which may constitute a promising molecular therapeutic target for treating MIRI.

RNAi-Mediated Down-Regulation of CD47 Protects against Ischemia/Reperfusion-Induced Myocardial Damage via Activation of eNOS in a Rat Model.

BACKGROUND/AIMS: Oxidative stress is strongly implicated in the pathogenesis of myocardial damage caused by ischemia reperfusion (I/R). Previous studies have confirmed that cardiac CD47 drives left ventricular heart failure. However, the role for CD47 in myocardial I/R injury (MIRI) has not previously been proposed. This study was designed to investigate whether down-regulation of CD47 using RNA interference (RNAi) technology can relieve inhibition of nitric oxide signaling and attenuate myocardial damage in a rat model of I/R. METHODS: Male Sprague-Dawley rats (n = 40) were randomly allocated to four groups and pre-treated either with saline (Sham and I/R groups), or adenovirus expressing either control (Ad-EGFP-N) or CD47-targeting (Ad-EGFP-CD47) RNAi. After four days, the rat MIRI model was established by occluding the left anterior descending coronary artery for 30 min, followed by reperfusion for 3 h. Heart tissue was harvested and assessed by immunohistochemistry, western blot, and quantitative RT-PCR. Outcome measures included infarct size, myocardial enzyme (creatine kinase, creatine kinase-MB, and lactate dehydrogenase) levels in serum, markers of oxidative stress, and morphological changes to the myocardium. RESULTS: Delivery of Ad-EGFP-CD47 RNAi into the myocardium remarkably decreased CD47 expression levels. Down-regulation of CD47 was significantly associated with reduced infarct size and serum levels of myocardial enzymes, increased activity of endothelial nitric oxide synthase, increased levels of nitric oxide, and decreased levels of oxidative stress. CONCLUSION: These data indicate that down-regulation of CD47 exerts a protective effect against MIRI, which may be attributable to attenuation of oxidative stress via activation of the eNOS/NO signaling pathway.

The short- and medium-term results of transcatheter closure of atrial septal defect with severe pulmonary arterial hypertension.

We investigated the short-term and medium-term results in patients with pulmonary arterial hypertension (PAH) associated with atrial septal defect (ASD) undergoing transcatheter closure. Fifteen patients with severe PAH associated with ASD who underwent successful occluder implantation from 2007 to 2010 were included. Clinical, echocardiographic, and hemodynamic data were reviewed. Severe PAH was defined as pulmonary arterial systolic pressure measured by catheterization was ≥60 mmHg and pulmonary vascular resistance (PVR) ≥6 Wood Units (WU). Compared with baseline, the 6-minwalking distance significantly increased by 29.7 ± 26.3 m (P < 0.001) at 3 months (short-term) and 65.4 ± 63.6 m (P < 0.001) at 23.4 ± 9.7 months (medium-term), World Health Organization function class considerably improved after postclosure short-term and medium-term. Repeat cardiac catheterization (n = 7) showed that mean pulmonary arterial pressure decreased from 51.6 ± 9.4 mmHg at baseline to 21.0 ± 3.8 mmHg (P < 0.001) at follow-up of 12 months. The PVR decreased by 5.6 ± 1.1 WU (P < 0.001). Through carefully selected patients with severe PAH associated with ASD, transcatheter closure can be safely performed with a promising short-term and medium-term outcome. Trial occlusion is an effective way for deciding the reversibility of severe PAH in ASD patients. The role of aerosolized iloprost for pulmonary vasoreactivity testing in patients with severe PAH secondary to ASD requires further investigation.

The effects of atorvastatin on pulmonary arterial hypertension and expression of p38, p27, and Jab1 in rats.

Statins have recently come under evaluation for the treatment of pulmonary arterial hypertension (PAH). The aim of this study was to examine the effects of atorvastatin on the clinical manifestations and expression of p38, p27 and Jab1 using a rat PAH model. Ninety-six male Wistar rats were divided into control (receiving no surgical treatment), vehicle and treatment groups, among which the last two groups underwent left pneumonectomy and were then treated with monocrotaline (MCT, 60 mg/kg). Both control and vehicle groups subsequently received saline, and the treatment group received atorvastatin (20 mg/kg) by stomach catheter. Rats were sacrificed, and mean pulmonary arterial pressure (mPAP) and right ventricle hypertrophy index (RVHI) were measured. The expression of p38, p27, and Jab1 was evaluated by immunohistochemistry and Western blotting. At 28 days, mPAP and RVHI and expression levels of Jab1 and p38 in the vehicle group were significantly higher than those in the treatment and control groups. However, the expression of p27 was lowest in the vehicle group among the three groups. Atorvastatin reduced PAP and RVHI in the rat PAH model, decreased expression of p38 and Jab1 but increased expression of p27.