The microRNA-dependent cell fate of multipotent stromal cells differentiating to endothelial cells.

In the endothelial recovery process, bone marrow-derived MSCs are a potential source of cells for both research and therapy, and their capacities to self-renew and to differentiate into all the cell types in the human body make them a promising therapeutic agent for remodeling cellular differentiation and a valuable resource for the treatment of many diseases. Based on the results provided in a miRNA database, we selected miRNAs with unique targets in cell fate-related signaling pathways. The tested miRNAs targeting GSK-3ß (miR-26a), platelet-derived growth factor receptor, and CD133 (miR-26a and miR-29b) induced MSC differentiation into functional ECs, whereas miRNAs targeting VEGF receptor (miR-15, miR-144, miR-145, and miR-329) inhibited MSC differentiation into ECs through VEGF stimulation. In addition, the expression levels of these miRNAs were correlated with in vivo physiological endothelial recovery processes. These findings indicate that the miRNA expression profile is distinct for cells in different stages of differentiation from MSCs to ECs and that specific miRNAs can function as regulators of endothelialization.

MicroRNA-17-mediated down-regulation of apoptotic protease activating factor 1 attenuates apoptosome formation and subsequent apoptosis of cardiomyocytes.

Heart diseases such as myocardial infarction (MI) can damage individual cardiomyocytes, leading to the activation of cell death programs. The most scrutinized type of cell death in the heart is apoptosis, and one of the key events during the propagation of apoptotic signaling is the formation of apoptosomes, which relay apoptotic signals by activating caspase-9. As one of the major components of apoptosomes, apoptotic protease activating factor 1 (Apaf-1) facilitates the formation of apoptosomes containing cytochrome c (Cyto-c) and deoxyadenosine triphosphate (dATP). Thus, it may be possible to suppress the activation of the apoptotic program by down-regulating the expression of Apaf-1 using miRNAs. To validate this hypothesis, we selected a number of candidate miRNAs that were expected to target Apaf-1 based on miRNA target prediction databases. Among these candidate miRNAs, we empirically identified miR-17 as a novel Apaf-1-targeting miRNA. The delivery of exogenous miR-17 suppressed Apaf-1 expression and consequently attenuated formation of the apoptosome complex containing caspase-9, as demonstrated by co-immunoprecipitation and immunocytochemistry. Furthermore, miR-17 suppressed the cleavage of procaspase-9 and the subsequent activation of caspase-3, which is downstream of activated caspase-9. Cell viability tests also indicated that miR-17 pretreatment significantly prevented the norepinephrine-induced apoptosis of cardiomyocytes, suggesting that down-regulation of apoptosome formation may be an effective strategy to prevent cellular apoptosis. These results demonstrate the potential of miR-17 as an effective anti-apoptotic agent.

Video-assisted thoracoscopic diaphragm oblique resection simplified with an endostapler for diaphragm eventration.

Diaphragm plication has recently become a standard operation for diaphragm eventration. The surgical experience for the patient has improved with the development of minimally invasive operations, but the operator's convenience has not improved significantly. We performed video-assisted thoracoscopic surgery for a diaphragm oblique resection using endostaplers in 10 patients. The total operation time was 39.5 minutes; all patients' symptoms disappeared postoperatively. This presentation will help more thoracic surgeons simplify this operation on the diaphragm.

Up-regulation of miR-26a promotes apoptosis of hypoxic rat neonatal cardiomyocytes by repressing GSK-3ß protein expression.

Myocardial ischemia is the major cause of morbidity and mortality due to cardiovascular diseases. This disease is a severe stress condition that causes extensive biochemical changes which trigger cardiac cell death. Stress conditions such as deprivation of glucose and oxygen activate the endoplasmic reticulum in the cytoplasm of cells, including cardiomyocytes, to generate and propagate apoptotic signals in response to these conditions. microRNAs (miRNAs) are a class of small non-coding RNAs that mediate posttranscriptional gene silencing. The miRNAs play important roles in regulating cardiac physiological and pathological events such as hypertrophy, apoptosis, and heart failure. However, the roles of miRNAs in reactive oxygen species (ROS)-mediated injury on cardiomyocytes are uncertain. In this study, we identified at the apoptotic concentration of H(2)O(2), miR-26a expression was increased. To determine the potential roles of miR-26a in H(2)O(2)-mediated cardiac apoptosis, miR-26a expression was regulated by a miR-26a or an anti-miR-26a. Overexpression of miR-26a increased apoptosis as determined by upregulation of Annexin V/PI positive cell population, caspase-3 activity and expression of pro-apoptotic signal molecules, whereas inhibition of miR-26a reduced apoptosis. We identified GSK3B as a direct downstream target of miR-26a. Furthermore, miR-26a attenuated viability and increased caspase-3 activity in normal cardiomyocytes. This study demonstrates that miR-26a promotes ROS-induced apoptosis in cardiomyocytes. Thus, miR-26a affects ROS-mediated gene regulation and cellular injury response.

Phorbol myristate acetate differentiates human adipose-derived mesenchymal stem cells into functional cardiogenic cells.

To achieve effective regeneration of injured myocardium, it is important to find physiological way of improving the cardiogenic differentiation of stem cells. Previous studies demonstrated that cardiomyocytes from bone marrow-derived mesenchymal stem cells (BMSCs) activated with phorbolmyristate acetate (PMA), a protein kinase C (PKC) activator, restore electromechanical function in infarcted rat hearts. In this study, we investigated the effect of PMA on cardiogenic differentiation of adipose-derived MSCs (ASCs) for clinical applications. To confirm the effect of PMA, ASCs treated with 1µM PMA were grown for nine days. The expression of cardiac-specific markers (cardiac troponin T, myosin light chain, myosin heavy chain) in PMA-treated MSCs was demonstrated by immunocytochemistry. Alhough few α(1A) receptors exist in ASCs, α(1)-adrenergic receptor subtypes were preferentially expressed in PMA-treated ASCs. Moreover, expression of the ß-adrenergic and muscarinic receptors increased in PMA-treated ASCs compared to normal cells. The mRNA levels of Ca(2+)-related factors (SERCA 2a; sarcoplasmic reticulum Ca(2+)-ATPase, LTCC; L-type Ca(2+) channel) in treated ASCs were similar to the levels in cardiomyocytes. Following the transplantation of chemically activated cardiogenic ASCs into infarcted myocardium, histological analysis showed that infarct size, interstitial fibrosis, and apoptotic index were markedly decreased and cardiac function was restored. In conclusion, PMA might induce the cardiogenic differentiation of human ASCs as well as BMSCs. This result suggests successful use of human ASCs in cardiac regeneration therapy.

Corrigendum: Small molecule-mediated up-regulation of microRNA targeting a key cell death modulator BNIP3 improves cardiac function following ischemic injury.

This corrects the article DOI: 10.1038/srep23472.

Small molecule-mediated up-regulation of microRNA targeting a key cell death modulator BNIP3 improves cardiac function following ischemic injury.

Genetic ablation of BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3), an essential regulator of cardiac cell death, is an effective way to prevent cardiac cell death triggered by pathologic conditions. However, currently there exists no known means, such as inhibitors, to down-regulate BNIP3 in mature heart. Here, we report that a small molecule inducer of microRNA-182 (miR-182) suppressed ischemia/reperfusion (I/R)-induced cardiac cell death by down-regulating BNIP3. We first selected miR-182 as a potent BNIP3-targeting miRNA based on miRNA-target prediction databases and empirical data. The subsequent screening of small molecules for inducing miR-182 expression identified Kenpaullone as a hit compound. Both exogenous miR-182 and Kenpaullone significantly suppressed hypoxia-induced cardiomyocyte death in vitro. To investigate the effect of changing substituents of Kenpaullone on miR-182 expression, we synthesized 9 derivatives of Kenpaullone. Among these derivatives, compound 5 showed significantly improved ability to induce miR-182 expression. The results of the in vivo study showed that compound 5 significantly improved heart function following I/R-injury in rats. Our study provides strong evidence that the small molecule-mediated up-regulation of miRNAs is a viable strategy to down-regulate target proteins with no known chemical inhibitor and that compound 5 may have potential to prevent I/R-inflicted cardiac cell death.

Impact of miRNAs on cardiovascular aging.

Aging is a multidimensional process that leads to an increased risk of developing severe diseases, such as cancer and cardiovascular, neurodegenerative, and immunological diseases. Recently, small non-coding RNAs known as microRNAs (miRNAs) have been shown to regulate gene expression, which contributes to many physiological and pathophysiological processes in humans. Increasing evidence suggests that changes in miRNA expression profiles contribute to cellular senescence, aging and aging-related diseases. However, only a few miRNAs whose functions have been elucidated have been associated with aging and/or aging-related diseases. This article reviews the currently available findings regarding the roles of aging-related miRNAs, with a focus on cardiac and cardiovascular aging.

1H-pyrrole-2,5-dione-based small molecule-induced generation of mesenchymal stem cell-derived functional endothelial cells that facilitate rapid endothelialization after vascular injury.

INTRODUCTION: Despite the success of interventional processes such as drug-eluting stents, complete prevention of restenosis is still hindered by impaired or delayed endothelialization or both. Here, we report that 1H-pyrrole-2,5-dione-based small molecule-generated mesenchymal stem cell-derived functional endothelial cells (MDFECs) facilitated rapid transmural coverage of injured blood vessels. METHODS: Small molecules that induced CD31 expression were screened by principal component analysis (PCA). Rat mesenchymal stem cells (MSCs) were treated with selected small molecules for up to 16 days, and the expression levels of CD90 and CD31 were examined by immunocytochemistry. In vitro functional assays of MDFECs, including tube formation assays and nitric oxide production assays, were performed. After MDFECs (intravenous, 3×10(6) cells per animal) were injected into balloon-injured rats, neointima formation was monitored for up to 21 days. The endothelial coverage of denuded blood vessels was evaluated by Evans Blue staining. The functionality of repaired blood vessels was evaluated by measuring vasorelaxation and hemodynamic changes. Additionally, derivatives of the selected small molecules were examined for their ability to induce endothelial markers. RESULTS: PCA indicated that 3-(2,4-dichlorophenyl)-4-(1-methyl-1H-indol-3-yl)-1H-pyrrole-2,5-dione effectively induced MDFECs. MDFECs inhibited the neointima formation of denuded blood vessels by facilitating more rapid endothelialization. Further examination indicated that derivatives with a 1H-pyrrole-2,5-dione moiety are important for initiating the endothelial cell differentiation of MSCs. CONCLUSIONS: Small molecules with 1H-pyrrole-2,5-dione as a core structure have great potential to improve the efficacy of MSC-based cell therapy for vascular diseases, such as atherosclerosis and restenosis.

Surgical treatment of thoracic menigocele associated with neurofibromatosis and kyphoscoliosis.

A 46-year-old man presented with a lateral thoracic meningocele associated with cutaneous neurofibromatosis type I and kyphoscoliosis of the thoracic spine upon medical examination. In the majority of such cases, these meningoceles remain asymptomatic, but surgery is indicated when giant or symptomatic cysts are present. The large thoracic meningocele was successfully extirpated through the transthoracic approach in combination with lumbar puncture and cerebrospinal drainage for decompression of the cyst.