DJ-1 alleviates anoxia and hypoglycemia injury in cardiac microvascular via AKT and GSH.

Cardiac microvascular damage, which is often caused by anoxia and hypoglycemia, is associated with the development of cardiac injury. DJ-1 encodes a peptidase C56 protein family related protein, is has been linked to oxidative stress in various cells such as neurons, COPD epithelial cells, and macrophages. However, the effect of DJ-1 towards oxidative stress caused by anoxia and hypoglycemia of cardiac microvascular endothelial cells (CMEC) remains unclear. In this study, we investigated the role and underlying molecular mechanism of DJ-1 in CMEC with anoxia/hypoglycemic (A/H) injury. We found that the mRNA and the protein expression of DJ-1 in CMEC with A/H injury were significantly downregulated. DJ-1 overexpression by pcDNA.3.1-DJ-1 transfection elevated cell viability while it inhibited LDH leakage, cell apoptosis, caspase-3 activity, ROS level, and MDA contents, while knockdown of DJ-1 has the opposite results. In addition, tube formation was increased in DJ-1 overexpression, while it was decreased in DJ-1 knockdown CMEC with A/H injury. In addition, our results indicated that DJ-1 can regulate glutathione (GSH) levels by modulating AKT activity in CMEC with A/H injury. The downregulation of AKT and GSH may remove the protective role of DJ-1 against A/H injury in CMEC. Taken together, this study showed that DJ-1 upregulation protected CMEC against A/H injury via the AKT/GSH signaling pathway.

MiR-599 regulates LPS-mediated apoptosis and inflammatory responses through the JAK2/STAT3 signalling pathway via targeting ROCK1 in human umbilical vein endothelial cells.

MicroRNA plays an integral role in the development of atherosclerosis. Our study aimed to investigate the roles of miR-599 in lipopolysaccharide (LPS)-induced endothelial damage in human umbilical vein endothelial cells (HUVECs). HUVECs were transfected with a miR-599 mimic and negative control, and then exposed to LPS. The expression of miR-599 was detected by quantitative real time-polymerase chain reaction (RT-qPCR). Cell viability was analyzed by CCK-8 assay and trypan blue exclusion assay; the formation of DNA fragments was tested by Cell Death Detection ELISA Plus kit; the incidence of apoptosis was detected by flow cytometry; the expression of p53 and cleaved-caspase 3 (c-caspase 3) was evaluated by western blot. Moreover, the mRNA levels and concentrations of tumour necrosis factor (TNF)-α, interleukin (IL)-6, ICAM-1 and VCAM-1 were assayed by RT-qPCR and ELISA. The results showed that overexpression of miR-599 increased cell viability, reduced DNA fragments, the incidence of apoptosis, as well as the protein levels of p53 and c-caspase 3 in the presence of LPS. TNF-α, IL-6, ICAM-1 and VCAM-1 mRNA levels and concentrations were also decreased upon miR-599 upregulation. In addition, the dual luciferase reporter assay demonstrated that ROCK1 is a direct target of miR-599. MiR-599 overexpression inhibited ROCK1 expression. Induced expression of ROCK1 reversed the roles of miR-599 in apoptosis and inflammation. The gain function of miR-599 function inhibited activation of the JAK2/STAT3 signalling pathway, which was abrogated by overexpression of ROCK1. Taken together, our results indicate that miR-599 attenuates LPS-caused cell apoptosis and inflammatory responses through the JAK2/STAT3 signalling pathway via targeting ROCK1.

miR-203 accelerates apoptosis and inflammation induced by LPS via targeting NFIL3 in cardiomyocytes.

Myocarditis is an inflammatory disease of the myocardium. MicroRNA-203 (miR-203) is involved in various physiological and pathological processes. In this work, we aimed to explore the roles and potential mechanisms of miR-203 in myocarditis in vitro. Cardiomyocyte H9c2 was subjected to 10 µg/mL lipopolysaccharide (LPS) for 24 hours. Real-time polymerase chain reaction analysis revealed that LPS upregulated miR-203 expression in H9c2 cells. Cell counting kit-8 (CCK-8) and lactate dehydrogenase (LDH) assays demonstrated that inhibition of miR-203 reduced cell injury induced by LPS. The cell apoptosis rate, caspase 3 activity, caspase 3/7 activities, and the expression of cleaved-caspase 3 (c-caspase 3) were declined upon miR-203 depletion. In addition, miR-203 silencing attenuated the expression and production of inflammatory cytokines (tumor necrosis factor-α, interleukin [IL]-6, and IL-8). On the contrary, overexpression of miR-203 showed the opposite trend in cell apoptosis and inflammation. Luciferase reporter assay confirmed that miR-203 could bind with the nuclear factor interleukin-3 (NFIL3) 3'-untranslated regions (3'-UTR), and miR-203 regulated the expression of NFIL3 negatively. Moreover, NFIL3 silencing partly abolished the myocardial protective functions of miR-203 inhibitor. Herein, we suggest that miR-203 promoted cell apoptosis and inflammation induced by LPS via targeting NFIL3.

miR-200a mediates protection of thymosin ß-4 in cardiac microvascular endothelial cells as a novel mechanism under hypoxia-reoxygenation injury.

Thymosin ß-4 (Tß4) is a ubiquitous protein, which has been suggested to regulate multiple cell signal pathways and a variety of cellular functions. However, the role Tß4 plays in the cardiac microvascular endothelial cells (CMECs) under myocardial ischemia/reperfusion injury is currently unknown. Here we investigated the effects of Tß4 on hypoxia/reoxygenation (H/R) induced CMECs injury and its potential molecular mechanism. Cultured CMECs were positively identified by flow cytometry using antibody against CD31 and VWF/Factor VIII, which are constitutively expressed on the surface of CMECs. Then the reduced level of Tß4 was detected in H/R-CMECs by a real-time quantitative polymerase chain reaction. To determine the effects of Tß4 on H/R-CMECs, we transfected the overexpression or silence vector of Tß4 into CMECs under H/R condition. Our results indicated that H/R treatment could reduce proliferation, increased apoptosis, adhesion, and reactive oxygen species (ROS) production in CMECs, which were attenuated by Tß4 overexpression or aggravated by Tß4 silencing, implying Tß4 is able to promote CMECs against H/R-induced cell injury. Furthermore, the microRNA-200a (miR-200a) level was also increased by Tß4 in H/R-CMECs or reduced by Tß4 small interfering RNA. To investigated the mechanism of protective effects of Tß4 on CMECs injury, the miR-200a inhibitor was transfected into H/R-CMECs. The results indicated that inhibition of miR-200a inversed the protection of Tß4 on H/R-CMECs, specifically including cell proliferation, cell adhesion, cell apoptosis, and ROS production, as well as nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation. In conclusion, our results determined that Tß4 attenuated H/R-induced CMECs injury by miR-200a-Nrf2 signaling.

NDRG1 Downregulates ATF3 and Inhibits Cisplatin-Induced Cytotoxicity in Lung Cancer A549 Cells.

N-myc downstream regulated gene 1 (NDRG1) plays a variety of roles in human cancers. Our previous studies showed that NDRG1 expression is elevated in non-small cell lung cancer and contributes to cancer growth. However, its function in apoptosis and chemoresistance in malignant tumors, including lung cancer, is not yet fully understood. In this study, we investigated the roles of NDRG1 in chemoresistance to cisplatin in lung cancer cells. We found that overexpression of NDRG1 significantly reduced cisplatin-induced cytotoxicity in lung cancer A549 cells, while overexpression of activating transcription factor 3 (ATF3), a stress-inducible gene found to be associated with apoptosis in some human cancers, significantly promoted cytotoxicity (P < 0.05). Further investigation showed that overexpression of NDRG1 significantly downregulated ATF3 and P53 expression in A549 cells, while overexpression of ATF3 significantly upregulated P53 expression (P < 0.05). In addition, cisplatin significantly upregulated ATF3, phospho-P53(ser46), and cleaved caspase 3 expression in lung cancer cells, but overexpression of NDRG1 in the presence of cisplatin reduced the level of these proteins elevated by cisplatin (P < 0.05). While, overexpression of ATF3 significantly promoted the cytoxicity induced by cisplatin in 1299 cells (p<0.05) (Figure 4), but overexpression of NDRG1 didn't regulate the cytoxicity induced by cisplatin (p>0.05). These results indicate that NDRG1 may contribute to cisplatin-resistance in lung cancer, possibly due to its function in the regulation of ATF3 expression.

MiR-200a mediates protection of thymosin beta 4 in cardiac microvascular endothelial cells as a novel mechanism under hypoxia-reoxygenation injury.

Thymosin beta-4 (Tß4) is a ubiquitous protein, which has been suggested to regulate multiple cell signal pathways and a variety of cellular functions. However, the role Tß4 plays in the cardiac microvascular endothelial cells (CMECs) under myocardial ischemia/reperfusion injury (MIRI) is currently unknown. Here we investigated the effects of Tß4 on hypoxia/reoxygenation (H/R) induced CMECs injury and its potential molecular mechanism. Cultured CMECs were positively identified by flow cytometry using antibody against CD31 and VWF/Factor VIII, which are constitutively expressed on the surface of CMECs. Then the reduced level of Tß4 was detected in H/R-CMECs by RT-qPCR. In order to determine the effects of Tß4 on H/R-CMECs, we transfected the overexpression or silence vector of Tß4 into CMECs under H/R condition. Our results indicated that H/R treatment could reduce proliferation, increased apoptosis, adhesion and ROS production in CMECs, which were attenuated by Tß4 overexpression or aggravated by Tß4 silence, implying Tß4 is able to promote CMECs against H/R-induced cell injury. Furthermore, the microRNA 200a (miR-200a) level was also increased by Tß4 in H/R-CMECs or reduced by Tß4 siRNA. To investigated the mechanism of protective effects of Tß4 on CMECs injury, the miR-200a inhibitor was transfected into H/R-CMECs. The results indicated that inhibition of miR-200a inversed the protection of Tß4 on H/R-CMECs, specifically including cell proliferation, cell adhesion, cell apoptosis and ROS production, as well as nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation. In conclusion, our results determined that Tß4 attenuated H/R induced CMECs injury by miR-200a-Nrf2 signaling. This article is protected by copyright. All rights reserved.

Knockdown of Mmu-circ-0001380 Attenuates Myocardial Ischemia/Reperfusion Injury via Modulating miR-106b-5p/Phlpp2 Axis.

Myocardial ischemia/reperfusion (MI/R) injury induces myocardial damage and dysfunction. Increasing evidence has confirmed that circular RNAs (circRNAs) play crucial roles in regulating MI/R. Mmu-circ-0001380 has identified to be highly expressed in myocardium of MI/R mouse model. However, its biological function and molecular mechanism in MI/R injury are still unclear. Here, we demonstrated that knockdown of cric-0001380 attenuated myocardial injury of MI/R mice. In vitro, silence of circ-0001380 significantly enhanced viability, and inhibited apoptosis and oxidative stress in HL-1 cells under oxygen-glucose deprivation/reoxygenation (OGD/R). Mmu-miR-106b-5p interacted with circ-0001380, and suppressed the expression of pleckstrin homology domain and leucine rich repeat protein phosphatase 2 (Phlpp2). The miR-106b-5p/Phlpp2 axis mediated the effect of circ-0001380 on OGD/R-induced apoptosis through regulating the phosphorylation of p38, and further involved in regulating the viability and oxidative stress of HL-1 cells. In conclusion, circ-0001380 downregulation relieves MI/R injury via regulating the miR-106b-5p/Phlpp2 axis. The present study indicates that mmu-circ-0001380 exacerbates the myocardial ischemia/reperfusion injury through modulating the miR-106b-5p/Phlpp2 axis in vitro and in vivo.

MiR-483-3p inhibition ameliorates myocardial ischemia/reperfusion injury by targeting the MDM4/p53 pathway.

MiR-483-3p is involved in the pathogenesis of acute myocardial infarctions, but its association with myocardial ischemia reperfusion (IR) remains mostly unknown. In this study, an in vitro model of myocardial IR injury was established by putting H9c2 cells into hypoxia reoxygenation (HR) treatment to explore the effects and possible mechanisms of miR-483-3p in myocardial IR injury. HR exposure resulted in increased miR-483-3p levels in H9c2 cells. MiR-483-3p was overexpressed or downregulated in H9c2 cells by transfection of miR-483-3p mimic or miR-483-3p inhibitor. In HR-treated H9c2 cells, MiR-483-3p mimics inhibited cell viability, promoted lactate dehydrogenase release, and increased apoptosis, but miR-483-3p inhibitors caused the opposite effects. MDM4 was verified to be the target mRNA of miR-483-3p and negatively modulated by miR-483-3p. MiR-483-3p inhibitor upregulated MDM4 and Bcl-2, but downregulated p53 and Bax in HR-treated H9c2 cells, whereas miR-483-3p overexpression produced the opposite effects.. Moreover, MDM4 siRNA transfection partially reversed the role of miR-483-3p inhibition in HR injury and p53 pathway inactivation of H9c2 cells. In summary, by targeting the MDM4/p53 pathway, miR-483-3p inhibition may alleviate myocardial HR injury. MiR-483-3p may be a potential therapeutic target of myocardial IR injury.