Exosomal MALAT1 from macrophages treated with high levels of glucose upregulates LC3B expression via miR-204-5p downregulation.

BACKGROUND: Metastasis-associated lung adenocarcinoma transcript 1 ( MALAT1 ) plays a critical role in the pathophysiology of diabetes-related complications. However, whether macrophage-derived MALAT1 affects autophagic activity under hyperglycemic conditions is unclear. Therefore, we investigated the molecular regulatory mechanisms of macrophage-derived MALAT1 and autophagy under hyperglycemic conditions. METHODS: Hyperglycemia was induced by culturing macrophages in 25 mM glucose for 1 hour. Exosomes were extracted from the culture media. A rat model of carotid artery balloon injury was established to assess the effect of MALAT1 on vascular injury. Reverse transcription, real-time quantitative polymerase chain reaction, western blotting, immunohistochemical staining, and luciferase activity assays were performed. RESULTS: Stimulation with high levels of glucose significantly enhanced MALAT1 expression in macrophage-derived exosomes. MALAT1 inhibited miR-204-5p expression in macrophage-derived exosomes under hyperglycemic conditions. siRNA-induced silencing of MALAT1 significantly reversed macrophage-derived exosome-induced miR-204-5p expression. Hyperglycemic treatment caused a significant, exosome-induced increase in the expression of the autophagy marker LC3B in macrophages. Silencing MALAT1 and overexpression of miR-204-5p significantly decreased LC3B expression induced by macrophage-derived exosomes. Overexpression of miR-204-5p significantly reduced LC3B luciferase activity induced by macrophage-derived exosomes. Balloon injury to the carotid artery in rats significantly enhanced MALAT1 and LC3B expression, and significantly reduced miR-204-5p expression in carotid artery tissue. Silencing MALAT1 significantly reversed miR-204-5p expression in carotid artery tissue after balloon injury. MALAT1 silencing or miR-204-5p overexpression significantly reduced LC3B expression after balloon injury. CONCLUSION: This study demonstrated that hyperglycemia upregulates MALAT1 . MALAT1 suppresses miR-204-5p expression and counteracts the inhibitory effect of miR-204-5p on LC3B expression in macrophages to promote vascular disease.

Exosomal MALAT1 Derived from High Glucose-Treated Macrophages Up-Regulates Resistin Expression via miR-150-5p Downregulation.

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) plays a crucial role in the pathophysiological process associated with diabetes-related complications. The effect of high glucose levels on macrophage-derived exosomal MALAT1 is unknown. Therefore, we investigated the molecular regulatory mechanisms controlling exosomal MALAT1 in macrophages under high glucose treatment and the therapeutic target of macrophage-derived exosomal MALAT1 using a balloon injury model of vascular disease in diabetic rats. High glucose (25 mM) significantly increased MALAT1 expression in macrophage-derived exosomes. MALAT1 suppressed miR-150-5p expression in macrophage-derived exosomes under high-glucose conditions. Silencing MALAT1 using MALAT1 siRNA significantly reversed miR-150-5p expression induced by macrophage-derived exosomes. Macrophage-derived exosomes under high-glucose treatment significantly increased resistin expression in macrophages. Silencing MALAT1 and overexpression of miR-150-5p significantly decreased resistin expression induced by macrophage-derived exosomes. Overexpression of miR-150-5p significantly decreased resistin luciferase activity induced by macrophage-derived exosomes. Macrophage-derived exosome significantly decreased glucose uptake in macrophages and silencing MALAT1, resistin or overexpression of miR-150-5p significantly reversed glucose uptake. Balloon injury to the carotid artery significantly increased MALAT1 and resistin expression and significantly decreased miR-150-5p expression in arterial tissue. Silencing MALAT1 significantly reversed miR-150-5p expression in arterial tissue after balloon injury. Silencing MALAT1 or overexpression of miR-150-5p significantly reduced resistin expression after balloon injury. In conclusion, high glucose up-regulates MALAT1 to suppress miR-150-5p expression and counteracts the inhibitory effect of miR-150-5p on resistin expression in macrophages to promote vascular disease. Macrophage-derived exosomes containing MALAT1 may serve as a novel cell-free approach for the treatment of vascular disease in diabetes mellitus.

Chrysin boosts KLF2 expression through suppression of endothelial cell-derived exosomal microRNA-92a in the model of atheroprotection.

PURPOSE: Atherosclerosis and its related clinical complications are the leading cause of death. MicroRNA (miR)-92a in the inflammatory endothelial dysfunction leads to atherosclerosis. Krüppel-like factor 2 (KLF2) is required for vascular integrity and endothelial function maintenance. Flavonoids possess many biological properties. This study investigated the vascular protective effects of chrysin in balloon-injured carotid arteries. MATERIALS AND METHODS: Exosomes were extracted from human coronary artery endothelial cell (HCAEC) culture media. Herb flavonoids and chrysin were the treatments in these atheroprotective models. Western blotting and real-time PCRs were performed. In situ hybridization, immunohistochemistry, and immunofluorescence analyses were employed. RESULTS: MiR-92a increased after balloon injury and was present in HCAEC culture media. Chrysin was treated, and significantly attenuated the miR-92a levels after balloon injury, and similar results were obtained in HCAEC cultures in vitro. Balloon injury-induced miR-92a expression, and attenuated KLF2 expression. Chrysin increased the KLF2 but reduced exosomal miR-92a secretion. The addition of chrysin and antagomir-92a, neointimal formation was reduced by 44.8 and 49.0% compared with balloon injury after 14 days, respectively. CONCLUSION: Chrysin upregulated KLF2 expression in atheroprotection and attenuated endothelial cell-derived miR-92a-containing exosomes. The suppressive effect of miR-92a suggests that chrysin plays an atheroprotective role. Proposed pathway for human coronary artery endothelial cell (HCAEC)-derived exosomes induced by chrysin to suppress microRNA (miR)-92a expression and counteract the inhibitory effect of miR-92a on KLF2 expression in HCAECs. This provides an outline of the critical role of the herbal flavonoid chrysin, which may serve as a valuable therapeutic supplement for atheroprotection.

Cyclic stretching boosts microRNA-499 to regulate Bcl-2 via microRNA-208a in atrial fibroblasts.

MicroRNAs that modulate transcription can regulate other microRNAs and are also up-regulated under pathological stress. MicroRNA-499 (miR-499), microRNA-208a (miR-208a) and B-cell lymphoma 2 (Bcl-2) play roles in cardiovascular diseases, such as direct reprogramming of cardiac fibroblast into cardiomyocyte and cardiomyocyte apoptosis. Whether miR208a, miR499 and Bcl-2 were critical regulators in cardiac fibroblast apoptosis under mechanical stretching conditions in human cardiac fibroblasts-adult atrial (HCF-aa) was investigated. Using negative pressure, HCF-aa grown on a flexible membrane base were cyclically stretched to 20% of their maximum elongation. In adult rats, an aortocaval shunt was used to create an in vivo model of volume overload. MiR208a was up-regulated early by stretching and returned to normal levels with longer stretching cycles, whereas the expression of miR499 and Bcl-2 was up-regulated by longer stretching times. Pre-treatment with antagomir-499 reversed the miR-208a down-regulation, whereas Bcl-2 expression could be suppressed by miR-208a overexpression. In the HCF-aa under stretching for 1 h, miR-499 overexpression decreased pri-miR-208a luciferase activity; this inhibition of pri-miR-208a luciferase activity with stretching was reversed when the miR-499-5p binding site in pri-miR-208a was mutated. The addition of antagomir-208a reversed the Bcl-2-3'UTR suppression from stretching for 1 h. Flow cytometric analysis revealed that pre-treatment with miR-499 or antagomir-208a inhibited cellular apoptosis in stretched HCF-aa. In hearts with volume overload, miR-499 overexpression inhibited myocardial miR-208a expression, whereas Bcl-2 expression could be suppressed by the addition of miR-208a. In conclusion, miR-208a mediated the regulation of miR-499 on Bcl-2 expression in stretched HCF-aa and hearts with volume overload.

Hyperbaric oxygen-induced long non-coding RNA MALAT1 exosomes suppress MicroRNA-92a expression in a rat model of acute myocardial infarction.

Hyperbaric oxygen (HBO) improves angiogenesis. The effect of HBO on metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a pro-angiogenic long non-coding RNA, in cardiac myocyte-derived exosomes and acute myocardial infarction (AMI) is unknown. We aimed to investigate whether MALAT1 is altered in cardiac myocyte-derived exosomes in response to HBO as well as the molecular regulatory mechanisms of MALAT1 in cardiac myocytes treated with HBO. Cardiac myocytes were cultured, and HBO was applied at 2.5 atmosphere absolute in a hyperbaric chamber. Exosomes were extracted from the culture media. A rat model of AMI generated by the ligation of the left anterior descending artery was used. HBO significantly increased MALAT1 expression in cardiac myocytes and HBO-induced MALAT1 and exosomes attenuated miR-92a expression after myocardial infarction. Expression of krüppel-like factor 2 (KLF2) and CD31 was significantly decreased after infarction and HBO-induced exosomes significantly reversed the expression. Silencing of MALAT1 using MALAT1-locked nucleic acid GapmeR significantly attenuated KLF2 and CD31 protein expression after infarction induced by HBO-induced exosomes. HBO-induced exosomes also decreased infarct size significantly. HBO-induced exosomes from cardiac myocytes up-regulate MALAT1 to suppress miR-92a expression and counteract the inhibitory effect of miR-92a on KLF2 and CD31 expression in left ventricular myocardium after myocardial infarction to enhance neovascularization.

Antithrombotic Strategies in Patients with Atrial Fibrillation Following Percutaneous Coronary Intervention: A Systemic Review and Network Meta-Analysis of Randomized Controlled Trials.

Up to 10% of patients with atrial fibrillation (AF) undergo percutaneous coronary intervention (PCI). A systematic review and network meta-analysis were conducted by searching PubMed, Embase, and the Cochrane database of systematic reviews for randomized control trials that studied the safety and efficacy of different antithrombotic strategies in these patients. Six studies, including 12,158 patients were included. Compared to that in the triple antithrombotic therapy group (vitamin K antagonist (VKA) plus P2Y12 inhibitor and aspirin), thrombolysis in myocardial infarction (TIMI) major bleeding was significantly reduced in the dual antithrombotic therapy (non-vitamin K oral anticoagulants (NOACs) plus P2Y12 inhibitor) group by 47% (Odds ratio (OR), 0.53; 95% credible interval [CrI], 0.35-0.78; I2 = 0%). Besides, NOAC plus a P2Y12 inhibitor was associated with less intracranial hemorrhage compared to VKA plus single antiplatelet therapy (OR: 0.20, 95% CrI: 0.05-0.77). There was no significant difference in the trial-defined major adverse cardiac events or the individual outcomes of all-cause mortality, cardiovascular death, myocardial infarction, stroke or stent thrombosis among all antithrombotic strategies. In conclusion, antithrombotic strategy of NOACs plus P2Y12 inhibitor is safer than, and as effective as, the strategies including aspirin when used in AF patients undergoing PCI.

(-)-Epigallocatechin Gallate Promotes MicroRNA 145 Expression against Myocardial Hypoxic Injury through Dab2/Wnt3a/ß-catenin.

MicroRNA 145 (miR-145) is a critical modulator of cardiovascular diseases. The downregulation of myocardial miR-145 is followed by an increase in disabled-2 (Dab2) expression in cardiomyocytes. (-)-epigallocatechin gallate (EGCG) is a flavonoid that has been evaluated extensively due to its diverse pharmacological properties including anti-inflammatory effects. The aim of this study was to investigate the cardioprotective effects of EGCG under hypoxia-induced stress in vitro and in vivo. The hypoxic insult led to the suppression of miR-145 expression in cultured rat cardiomyocytes in a concentration-dependent manner. Western blotting and real-time PCR were performed. In rat myocardial infarction study, in situ hybridization, and immunofluorescent analyses were adopted. The western blot and real-time PCR data revealed that hypoxic stress with 2.5% O2 suppressed the expression of miR-145 and Wnt3a/ß-catenin in cultured rat cardiomyocytes but augmented Dab2. Treatment with EGCG attenuated Dab2 expression, but increased Wnt3a and ß-catenin in hypoxic cultured cardiomyocytes. Following in vivo myocardial infarction (MI) study, the data revealed the myocardial infarct area reduced by 48.5%, 44.6%, and 48.5% in EGCG (50mg/kg) or miR-145 dominant or Dab2 siRNA groups after myocardial infarction for 28 days, respectively. This study demonstrated that EGCG increased miR-145, Wnt3a, and ß-catenin expression but attenuated Dab2 expression. Moreover, EGCG ameliorated myocardial ischemia in vivo. The novel suppressive effect was mediated through the miR-145 and Dab2/Wnt3a/ß-catenin pathways.

Catalpol Ameliorates Neointimal Hyperplasia in Diabetic Rats.

Catalpol, an iridoid glycoside, is an isolated natural product of Rehmannia glutinosa, which has been reported to have antidiabetic properties. This study investigated the vascular protective effects of catalpol in hyperglycemic rats with balloon-injured carotid arteries. Balloon injury stress led to the upregulation of monocyte chemoattractant protein-1 expression in rats with streptozotocin-induced diabetes. Western blotting and real-time PCR were performed. In situ hybridization, immunohistochemistry, and confocal analyses were employed. Monocyte chemoattractant protein-1 levels were increased through streptozotocin induction or balloon injury. After treatment with catalpol, the neointimal hyperplasia area was reduced 2 weeks after balloon injury in hyperglycemic rats. Real-time PCR and immunohistochemical analysis demonstrated reduced levels of monocyte chemoattractant protein-1 2 weeks after the balloon injury. Monocyte chemoattractant protein-1 expression was significantly increased in balloon-injured rats compared with the control groups. Thus, treatment with catalpol affected monocyte chemoattractant protein-1 expression. This study demonstrated that catalpol downregulated monocyte chemoattractant protein-1 expression in carotid arteries and ameliorated neointimal hyperplasia in hyperglycemic rats. The suppressive effect of monocyte chemoattractant protein-1 suggests that it plays a key role in neointimal hyperplasia. The results imply that catalpol is potentially effective for preventing hyperglycemia-related ischemic cardiac diseases.

Hyperbaric oxygen boosts long noncoding RNA MALAT1 exosome secretion to suppress microRNA-92a expression in therapeutic angiogenesis.

BACKGROUND: Hyperbaric oxygen (HBO) could improve wound healing by enhancement of angiogenesis. The effect of HBO on metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a proangiogenic long noncoding RNA, and on endothelial cell-derived exosome is unknown. We aim to investigate both whether MALAT1 is altered in human coronary artery endothelial cells (HCAECs)-derived exosomes in response to HBO as well as the molecular regulatory mechanisms of MALAT1 in HCAECs under HBO treatment. METHODS AND RESULTS: HCAECs were cultured and HBO was applied at 2.5 atmosphere absolute (ATA) in a hyperbaric chamber. Exosomes were extracted from culture media. A rat model of hind-limb ischemia was performed by ligation of the right femoral artery. HBO at 2.5 ATA significantly increased MALAT1 expression in HCAECs and HCAECs-derived exosomes. MALAT1 suppressed miR-92a expression in HCAEC-derived exosomes under HBO. Silencing MALAT1 by MALAT1 siRNA significantly inhibited KLF2 mRNA expression induced by HBO, as did MiR-92a. MiR-92a significantly decreased KLF2 luciferase activity in HCAECs under HBO. HBO and HBO-induced exosomes significantly increased cell proliferation and the capillary-like network formation of HCAECs. MALAT1 siRNA and miR-92a overexpression significantly attenuated the cell proliferation and tube formation caused by HBO-induced exosome. HBO and HBO-induced exosomes significantly improved neovascularization in a rat model of hind-limb ischemia. CONCLUSIONS: HBO upregulates MALAT1 to suppress miR-92a expression and counteracts the inhibitory effect of miR-92a on KLF2 expression in HCAECs to enhance neovascularization. HBO-induced derivation of exosomes from HCAECs enhances angiogenesis. Exosomes containing MALAT1 might serve as a valuable therapeutic tool for neovascularization by HBO.

Effects of flavonoids on MicroRNA 145 regulation through Klf4 and myocardin in neointimal formation in vitro and in vivo.

MicroRNA 145 (miR-145) is a critical modulator of vascular smooth muscle cell (VSMC) phenotyping and proliferation. Flavonoids have been studied extensively due to their diverse pharmacological properties, including anti-inflammatory effects. The aims of this study is designed to evaluate the atheroprotective effects on angiotensin II (Ang II)-induced miR-145 and Klf4/myocardin expression in vitro and in vivo of flavonoids, including (-)-epigallocatechin gallate (EGCG), chrysin, wogonin, silibinin, and ferulic acid. Ang II significantly reduced the miR-145 compared with the control VSMC groups; all the tested flavonoids increased miR-145 in the 100 nM concentration. Among the test compounds, EGCG showed the strongest augmenting effect on miR-145 and myocardin, however, it also abolished Ang II-induced Klf4. A [3H]-thymidine incorporation proliferation assay demonstrated that EGCG inhibited Ang II-induced VSMC proliferation, and Klf4 siRNA presented with the similar results. Immunohistochemical analysis and confocal microscopy demonstrated increased Klf4 expression and the arterial lumen was narrowed after balloon injury 14 days. With the addition of EGCG (50 mg/kg) and Klf4 siRNA, neointimal formation was reduced by 40.7% and 50.5% compared with balloon injury 14 days; Klf4 expression also was attenuated. This study demonstrated EGCG increased miR-145 and attenuated Klf4, and ameliorated neointimal formation in vitro and in vivo. The novel suppressive effect was mediated through the miR-145 and Klf4/myocardin pathways.

Suppressive effect of epigallocatechin-3-O-gallate on endoglin molecular regulation in myocardial fibrosis in vitro and in vivo.

Epigallocatechin-3-O-gallate (EGCG), derived from green tea, has been studied extensively because of its diverse physiological and pharmacological properties. This study evaluates the protective effect of EGCG on angiotensin II (Ang II)-induced endoglin expression in vitro and in vivo. Cardiac fibroblasts (CFs) from the thoracic aorta of adult Wistar rats were cultured and induced with Ang II. Western blotting, Northern blotting, real-time PCR and promoter activity assay were performed. Ang II increased endoglin expression significantly as compared with control cells. The specific extracellular signal-regulated kinase inhibitor SP600125 (JNK inhibitor), EGCG (100 µM) and c-Jun N-terminal kinase (JNK) siRNA attenuated endoglin proteins following Ang II induction. In addition, pre-treated Ang II-induced endoglin with EGCG diminished the binding activity of AP-1 by electrophoretic mobility shift assay. Moreover, the luciferase assay results revealed that EGCG suppressed the endoglin promoter activity in Ang II-induced CFs by AP-1 binding. Finally, EGCG and the JNK inhibitor (SP600125) were found to have attenuated endoglin expression significantly in Ang II-induced CFs, as determined through confocal microscopy. Following in vivo acute myocardial infarction (AMI)-related myocardial fibrosis study, as well as immunohistochemical and confocal analyses, after treatment with endoglin siRNA and EGCG (50 mg/kg), the area of myocardial fibrosis reduced by 53.4% and 64.5% and attenuated the left ventricular end-diastolic and systolic dimensions, and friction shortening in hemodynamic monitor. In conclusion, epigallocatechin-3-O-gallate (EGCG) attenuated the endoglin expression and myocardial fibrosis by anti-inflammatory effect in vitro and in vivo, the novel suppressive effect was mediated through JNK/AP-1 pathway.

Admission hyperglycemia predicts poorer short- and long-term outcomes after primary percutaneous coronary intervention for ST-elevation myocardial infarction.

AIMS/INTRODUCTION: Admission hyperglycemia is associated with poor outcome in patients with myocardial infarction. The present study evaluated the relationship between admission glucose level and other clinical variables in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). MATERIALS AND METHODS: The 959 consecutive STEMI patients undergoing primary PCI were divided into five groups based on admission glucose levels of <100, 100-139, 140-189, 190-249 and ≥250 mg/dL. Their short- and long-term outcomes were compared. RESULTS: Higher admission glucose levels were associated with significantly higher in-hospital morbidity and mortality, the overall mortality rate at follow up, and the incidence of reinfarction or heart failure requiring admission or leading to mortality at follow up. The odds ratios (95% confidence interval) for in-hospital morbidity, in-hospital mortality, mortality at follow up and re-infarction or heart failure or mortality at follow up of patients with admission glucose levels ≥190 mg/dL, compared with those with admission glucose levels <190 mg/dL, were 2.12 (1.3-3.4, P = 0.001), 2.74 (1.4-5.5, P = 0.004), 2.52 (1.2-5.1, P = 0.01) and 1.70 (1.03-2.8, P = 0.04), respectively. Previously non-diabetic patients with admission glucose levels ≥250 mg/dL had significantly higher in-hospital morbidity or mortality (44 vs 70%, P = 0.03). Known diabetic patients had higher rates of reinfarction, heart failure or mortality at follow up in the 100-139 mg/dL (8 vs 27%, P = 0.04) and 140-189 mg/dL (11 vs 26%, P = 0.02) groups. CONCLUSIONS: Admission hyperglycemia, especially at glucose levels ≥190 mg/dL, is a predictor of poor prognosis in STEMI patients undergoing primary PCI.

Molecular mechanism of (-)-epigallocatechin-3-gallate on balloon injury-induced neointimal formation and leptin expression.

Leptin contributes to the pathogenesis of vascular repair and cardiovascular events. This study evaluated the molecular mechanism of EGCG in balloon injury-induced leptin expression. According to immunohistochemical and confocal analyses, leptin expression was increased and the aortic lumen exhibited narrowing after balloon injury. EGCG treatment attenuated leptin expression and diminished neointimal formation. The in vitro study showed that angiotensin II (Ang II) induced the migration and proliferation of cultured vascular smooth muscle cells (VSMCs), whereas treatment with EGCG, leptin siRNA, and c-Jun siRNA inhibited the migration and proliferation of VSMCs significantly. The EMSA shows that balloon injury increased AP-1-binding activity, and EGCG and c-Jun siRNA inhibited the AP-1-binding activity. Western blot and real-time RT-PCR analyses revealed similar results in intimal tissue samples. In summary, balloon injury induces leptin expression in the carotid artery of rats, and EGCG inhibits leptin expression through the JNK/AP-1 pathway and also attenuates neointimal formation.

Stenotrophomonas maltophilia bloodstream infection: comparison between community-onset and hospital-acquired infections.

BACKGROUND/PURPOSE: Stenotrophomonas maltophilia has been recognized as an important nosocomial pathogen, but few reports have discussed S. maltophilia infection in the community settings. This study aimed to reveal characteristics of patients with community-onset S. maltophilia bloodstream infection (SMBSI), to specify the subgroup of healthcare-associated (HCA) infection in the community-onset group and to compare them with hospital-acquired (HA) SMBSI patients. MATERIALS AND METHODS: Medical charts of adult patients with SMBSI presenting to a medical center in southern Taiwan from May 2008 to October 2011 were reviewed and analyzed retrospectively. RESULTS: Among 153 patients, we observed a high percentage (38.6%) of SMBSI to be community onset. Among community-onset SMBSI, 45.8% were community-acquired (CA) and 54.2% were HCA. The crude mortality rates were 11.1%, 18.8%, and 60.6% in the CA, HCA, and HA groups, respectively. Structural/mechanical abnormalities were observed in 32.7% of all cases, and 60% of those were related to malignancy. Independent risk factors for mortality in community-onset SMBSI were liver cirrhosis, liver metastasis, and a high Pitt bacteremia score, whereas structural/mechanical abnormalities and a high Pitt bacteremia score related to increased mortality in HA SMBSI. CONCLUSION: Community-onset S. maltophilia infection deserves attention. Patients with community-onset SMBSI have reduced disease severity and lower mortality rate when compared to HA SMBSI. Underlying structural/mechanical abnormalities, especially those caused by malignancies, are common in SMBSI cases and should be investigated when bacteremia occurs.

A novel cancer therapeutic using thrombospondin 1 in dendritic cells.

Induction of thrombospondin 1 (TSP-1) is generally assumed to suppress tumor growth through inhibiting angiogenesis; however, it is less clear how TSP-1 in dendritic cells (DCs) influences tumor progression. We investigated tumor growth and immune mechanism by downregulation of TSP-1 in dendritic cells. Administration of TSP-1 small hairpin RNA (shRNA) through the skin produced anticancer therapeutic effects. Tumor-infiltrating CD4(+) and CD8(+) T cells were increased after the administration of TSP-1 shRNA. The expression of interleukin-12 and interferon-γ in the lymph nodes was enhanced by injection of TSP-1 shRNA. Lymphocytes from the mice injected with TSP-1 shRNA selectively killed the tumor cells, and the cytotoxicity of lymphocytes was abolished by depletion of CD8(+) T cells. Injection of CD11c(+) TSP-1-knockout (TSP-1-KO) bone marrow-derived DCs (BMDCs) delayed tumor growth in tumor-bearing mice. Similarly, antitumor activity induced by TSP-1-KO BMDCs was abrogated by depletion of CD8(+) T cells. In contrast, the administration of shRNAs targeting TSP-2, another TSP family member, did not extend the survival of tumor-bearing mice. Finally, TSP-1 shRNA functioned as an immunotherapeutic adjuvant to augment the therapeutic efficacy of Neu DNA vaccination. Collectively, the downregulation of TSP-1 in DCs produces an effective antitumor response that is opposite to the protumor effects by silencing of TSP-1 within tumor cells.

Mechanical stretch via transforming growth factor-ß1 activates microRNA208a to regulate endoglin expression in cultured rat cardiac myoblasts.

AIMS: MicroRNAs (miRNAs) play a role in cardiac remodelling. MiR208a is essential for the expression of the genes involved in cardiac hypertrophy and fibrosis. The mechanism of regulation of miR208a involved in cardiac hypertrophy by mechanical stress is still unclear. We sought to investigate the mechanism of regulation of miR208a and the target gene of miR208a in cardiac cells by mechanical stretch. METHODS AND RESULTS: Rat H9c2 cells (cardiac myoblasts) grown on a flexible membrane base were stretched via vacuum to 20% of maximum elongation at 60 cycles/min. Mechanical stretch significantly enhanced miR208a expression after 4 h of stretch. Exogenous addition of transforming growth factor-ß1 (TGF-ß1) increased miR208a expression, and pre-treatment with TGF-ß1 antibody attenuated the miR208a expression induced by stretch. Mechanical stretch significantly increased endoglin and collagen I expression for 6-24 h. Exogenous addition of TGF-ß1 and overexpression of miR208a up-regulated endoglin and collagen I expression, while antagomir208a and Smad3/4 inhibitor attenuated endoglin and collagen I expression induced by stretch. Mechanical stretch and TGF-ß1 increased Smad3/4-DNA binding activity and miR208a promoter activity, and TGF-ß1 antibody and Smad3/4 inhibitor decreased the Smad3/4-DNA binding activity and miR208a promoter activity induced by stretch. CONCLUSION: Cyclic mechanical stretch enhances miR208a expression in cultured rat cardiac myoblasts. The stretch-induced miR208a is mediated by TGF-ß1. Mir208a activates endoglin expression and may result in cardiac fibrosis.

Silibinin inhibits the invasion of IL-6-stimulated colon cancer cells via selective JNK/AP-1/MMP-2 modulation in vitro.

Silibinin is a flavonoid with antihepatotoxic properties and pleiotropic anticancer capabilities. This study investigated silibinin inhibition of cell invasion by down-regulating matrix metalloproteinase-2 (MMP-2) expression, via attenuation of activator protein-1 (AP-1) in IL-6-stimulated LoVo colon cancer cells. Western blot data showed that the expression of MMP-2 protein was reduced 1.6- or 1.7-fold over the control by treatment with silibinin or JNK inhibitor in the models. Similar results were revealed in zymography and confocal microscopy. Pretreatment with silibinin also abolished the binding activity of AP-1 and MMP-2 promoter activity via AP-1 binding, as observed by EMSA and luciferase assay. Finally, a [(3)H]-thymidine incorporation proliferation assay and cell migration assay demonstrated that silibinin inhibited IL-6-stimulated LoVo cell proliferation and invasion. Taken together, these data indicated that silibinin inhibits LoVo cell invasion with the reduction of MMP-2 presentation by attenuating AP-1 binding activity, suggesting a novel antimetastatic application for silibinin in colon cancer chemoprevention.

Functional role of wogonin in anti-angiogenesis.

Constitutive activation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway occurs commonly in cancer cells and endothelial cells, and contributes to angiogenesis. Wogonin is a compound with many biologically relevant properties. We previously reported that wogonin blocked IL-6-induced angiogenesis through suppression of VEGF expression, an important regulator of angiogenesis. However, the pathway involved in the suppressive effect of wogonin on IL-6-induced VEGF has not been completely clarified. This study aimed to investigate the molecular mechanisms participating in the suppression of wogonin on IL-6-induced VEGF in vitro, focusing on IL-6R/JAK1/STAT3/VEGF pathway. Both STAT3 siRNA and wogonin treatment resulted in an abolition of the expression of VEGF. Moreover, our data revealed that wogonin treatment after STAT3 knock-down did not further suppress VEGF expression. The addition of IL-6R siRNA or wogonin resulted in a decrease in the expression level of the phosphorylated JAK1 protein. Furthermore, wogonin significantly decreased the amount of phosphorylated STAT3. Finally, by EMSA, wogonin suppressed IL-6-induced STAT3 binding activity in a concentration-dependent manner. Taken together, our results show that wogonin suppresses IL-6-induced VEGF by modulating the IL-6R/JAK1/STAT3 signaling pathway. Based on this study, we suggest that wogonin may provide a new potential therapeutic option for treatment of IL-6-related pathological angiogenesis.

Angiotensin II mediates urotensin II expression by hypoxia in cultured cardiac fibroblast.

BACKGROUND: Urotensin II plays a role in myocardial remodelling. Cardiac fibroblasts play a critical role in the development of cardiac fibrosis. The effect of hypoxia on urotensin II expression in cardiac fibroblasts is poorly understood. We sought to investigate the regulation of urotensin II by hypoxia in cardiac fibroblasts and the effect of angiotensin II in the interaction with urotensin II. METHODS AND RESULTS: Rat cardiac fibroblasts were cultured in hypoxic chamber. Hypoxia significantly increased urotensin II expression and reactive oxygen species (ROS) production in cultured cardiac fibroblasts. Hypoxia-induced increase in urotensin II protein and ROS was significantly attenuated after the addition of SP600125, JNK siRNA or N-acetylcysteine before hypoxia treatment. The phosphorylated JNK protein was induced by hypoxia and was abolished by pretreatment with SP600125, losartan (an angiotensin II receptor antagonist) or N-acetylcysteine. The increased urotensin II expression by exogenous addition of angiotensin II was similar to that by hypoxia. Addition of losartan and angiotensin II antibody before hypoxia almost completely inhibited the increase in urotensin II induced by hypoxia. Hypoxia significantly increased the secretion of angiotensin II from cardiac fibroblasts and increased the collagen I protein expression. Hypoxia significantly increased the urotensin II promoter activity by 4·3-fold as compared to normoxic control. Urotensin II siRNA almost completely attenuated the collagen I protein expression induced by hypoxia. CONCLUSIONS: Hypoxia-induced urotensin II expression in cardiac fibroblast is mediated by angiotensin II and through ROS and JNK pathway. Urotensin II is a mediator of angiotensin II-induced cardiac fibrosis under hypoxia.