Rosiglitazone reduces diabetes angiopathy by inhibiting mitochondrial dysfunction dependent on regulating HSP22 expression.

The effects of rosiglitazone (RSG) in patients with type 2 diabetes mellitus (T2DM) remain controversial. Here, we first used network pharmacology to identify the common targets of RSG in the treatment of diabetes angiopathy (DA). Enrichment analysis found that the common genes were involved in the inflammatory response, leukocyte cell-cell adhesion, mitochondrion organization and oxidative stress. Our previous research confirmed that heat shock protein 22 (HSP22) suppresses diabetes-induced endothelial activation and injury by inhibiting mitochondrial reactive oxygen species (mtROS) formation and dysfunction. We then constructed HSP22 knockout mice with T2DM to investigate whether RSG protected the vascular endothelium by upregulating HSP22. Our study suggested that RSG reduced vascular endothelial cell activation and injury by decreasing monocyte adhesion and cytokine secretion and simultaneously upregulating HSP22 expression. Mechanistically, RSG inhibited mitochondrial oxidative stress and dysfunction by regulating PPAR-γ in a manner partially dependent on expression of HSP22, resulting in reduced DA.

Plasma exosomes induce inflammatory immune response in patients with acute myocardial infarction.

Exosomes are a kind of nanoscale extracellular vesicles with diameters of 30-100 nm and act as intracellular communication vehicles to influence cellular activities. Emerging pieces of evidence have indicated that exosomes play important roles in inflammation. However, the biological roles of plasma exosomes in acute myocardial infarction (AMI) patients have remained largely unexplored. In the current study, we found the plasma exosome levels were notably increased in patients with AMI in comparison with healthy controls (HCs), and AMI exosomes could induce endothelial cell injury. Furthermore, our data demonstrated that AMI exosomes triggered a pro-inflammatory immune response, at least partly depending on the activation of the NF-ĸB signalling. Together, AMI exosomes have pro-inflammatory properties and play a significant role in inflammation in AMI patients.

HIF-1α mediates the protective effect of plasma extracellular particles induced by remote ischaemic preconditioning on oxidative stress injury in human umbilical vein endothelial cells.

Remote ischaemic preconditioning (RIPC) is considered to alleviate myocardial ischaemia/reperfusion (I/R) injury. The present study explored whether blood plasma particulate matter, which is termed extracellular particles (EPs), and is released from cells during RIPC, could reduce H2O2-induced damage in human umbilical vein endothelial cells (HUVECs). Firstly, EPs were derived from volunteers who did or did not undergo RIPC. To induce RIPC in volunteers, a blood pressure cuff was alternatively inflated for 5 min and deflated for the same duration for four successive cycles. HUVECs were assigned to two groups: i) Group 1 was preincubated for 24 h with EPs from volunteers after sham-RIPC, then treated with H2O2 (1 mM; 6 h) to mimic the in vivo conditions of I/R-induced oxidative stress; and ii) group 2 was preincubated for 24 h with EPs from volunteers after RIPC, then treated with H2O2. Subsequently, EPs were derived from rats received sham-RIPC or RIPC and/or cadmium (Cd) pre-treatment. To induce RIPC in rats, a remote hind limb preconditioning stimulus was delivered using a blood pressure cuff attached at the inguinal level of the rat. The blood pressure cuff was alternatively inflated for 5 min and deflated for the same time period for four successive cycles. HUVECs were assigned to six groups: i) Group 1 was untreated; ii) group 2 received only H2O2 treatment (1 mM; 6 h); iii) group 3 was preincubated for 24 h with EPs from rats exposed to sham-RIPC, then treated with H2O2; iv) group 4 was preincubated for 24 h with EPs from rats that received an intraperitoneal injection of 1 mg/kg Cd [a pharmacological inhibitor of hypoxia-inducible factor 1-α (HIF-1α) in vivo] 180 min before sham-RIPC, then treated with H2O2; v) group 5 was preincubated for 24 h with EPs from rats exposed to RIPC, then treated with H2O2; and vi) group 6 was preincubated for 24 h with EPs from rats that received an intraperitoneal injection of 1 mg/kg Cd 180 min before RIPC, then treated with H2O2. Cell viability and cytotoxicity were monitored using Cell Counting Kit-8 and lactate dehydrogenase assays. Cell apoptosis and necrosis were assessed via flow cytometry and western blot analysis. A notable increase in EP concentration in the plasma of volunteers after RIPC compared with that in the plasma of volunteers after sham-RIPC was observed. RIPC-associated EPs (RIPC-EPs) from volunteers could improve cell viability and reduce cytotoxicity, cell apoptosis and necrosis in HUVECs treated with H2O2 in vitro. Furthermore, RIPC caused a significant increase in HIF-1α expression in the rat limb musculature. The apoptosis-reducing effect of RIPC-EPs was demonstrated to be counteracted by an intraperitoneal injection of Cd before RIPC in rats. A significant decrease in the EP levels precipitated from the plasma of rats that received Cd treatment before RIPC was observed compared with rats that did not receive Cd treatment. The present study suggested that HIF-1α mediated at least partly the protective effect of plasma RIPC-EPs on oxidative stress injury in HUVECs.

Pim-2 kinase inhibits inflammation by suppressing the mTORC1 pathway in atherosclerosis.

BACKGROUND: Inflammatory immunity theory has raised considerable concern in the pathogenesis of atherosclerosis. Proviral integration site of murine 2 (Pim-2) kinases functions in apoptosis pathways and the anti-inflammatory response. Here, we investigated whether Pim-2 kinase inhibits atherosclerotic inflammation by suppressing the mTORC1 pathway. METHODS: An atherosclerosis animal model was established by feeding ApoE -/- mice a high-fat diet. THP-1-derived macrophages were subjected to ox-LDL (50 µg/ml, 24h) conditions in vitro to mimic the in vivo conditions. RESULT: The protein expression of Pim-2 was upregulated in ox-LDL-treated THP-1-derived macrophages and an atherosclerotic mouse model. Additionally, ox-LDL upregulated the protein expression of p-mTOR, p-S6K1 and p-4EBP1, intracellular lipid droplets, free cholesterol and cholesterylester and the mRNA expression of inflammatory cytokines, including IL-6, MCP-1, TLR-4 and TNF-α, in THP-1-derived macrophages. Functionally, overexpressed Pim-2 (Pim-2 OE) attenuated atherosclerotic inflammation associated with the mTORC1 signaling pathway in vitro and in vivo, whereas knocked down Pim-2 (Pim-2 KD) markedly promoted atherosclerotic inflammation associated with upregulation of the mTORC1 signaling pathway. The plaque areas and lesions in the whole aorta and aortic root sections were alleviated in ApoE -/- mice with Pim-2 OE, but aggravated by Pim-2 KD. Additionally, an mTOR agonist (MHY1485) counteracted the anti-inflammatory effect of Pim-2 in ox-LDL-treated THP-1-derived macrophages after Pim-2 OE, whereas rapamycin rescued atherosclerotic inflammation in ox-LDL-treated THP-1-derived macrophages after Pim-2 KD. Furthermore, si-mTOR and si-Raptor alleviated the atherosclerotic proinflammatory effect in ox-LDL-treated THP-1-derived macrophages in a the background of Pim-2 KD. CONCLUSIONS: These results indicated that Pim-2 kinase inhibits atherosclerotic inflammation by suppressing the mTORC1 pathway.

LncRNA GAS5 inhibits NLRP3 inflammasome activation-mediated pyroptosis in diabetic cardiomyopathy by targeting miR-34b-3p/AHR.

Long noncoding RNA GAS5 is down-regulated in cardiomyocytes in diabetic cardiomyopathy (DCM). Here, we studied the involvement of GAS5 in DCM by analyzing its expression in DCM mouse model and cardiac muscle cell line (HL-1 cells). Compared with normal mice, GAS5 was severely down-regulated in heart tissues of DCM mice. GAS5 overexpression improved cardiac function and myocardial hypertrophy in DCM mice. In addition, the expression of NLRP3, caspase-1, Pro-caspase-1, IL-1ß and IL-18 were increased in heart tissues of DCM mice and high glucose-treated HL-1 cells, which was repressed by GAS5 up-regulation. GAS5 overexpression suppressed caspase-1 activity, LDH release and the levels of IL-1ß, IL-18 in the high glucose-treated HL-1 cells. Moreover, GAS5 regulated AHR expression by sponging miR-34b-3p. Furthermore, GAS5 overexpression suppressed NLRP3 inflammasome activation-mediated pyroptosis by regulating miR-34b-3p/AHR axis. In summary, our study demonstrates that GAS5 acts as a competing endogenous RNA to enhance AHR expression by sponging miR-34b-3p, which consequently represses NLRP3 inflammasome activation-mediated pyroptosis to improve DCM. Thus, our data provide a novel lncRNA GAS5 that could be a valuable target for DCM treatment.

NSD2 silencing alleviates pulmonary arterial hypertension by inhibiting trehalose metabolism and autophagy.

Nuclear receptor binding SET domain 2 (NSD2)-mediated metabolic reprogramming has been demonstrated to regulate oncogenesis via catalyzing the methylation of histones. The present study aimed to investigate the role of NSD2-mediated metabolic abnormality in pulmonary arterial hypertension (PAH). Monocrotaline (MCT)-induced PAH rat model was established and infected with adeno-associated virus carrying short hairpin RNA (shRNA) targeting NSD2. Hemodynamic parameters, ventricular function, and pathology were evaluated by microcatheter, echocardiography, and histological analysis. Metabolomics changes in lung tissue were analyzed by LC-MS. The results showed that silencing of NSD2 effectively ameliorated MCT-induced PAH and right ventricle dysfunction, and partially reversed pathological remodeling of pulmonary artery and right ventricular hypertrophy. In addition, the silencing of NSD2 markedly reduced the di-methylation level of H3K36 (H3K36me2 level) and inhibited autophagy in pulmonary artery. Non-targeted LC-MS based metabolomics analysis indicated that trehalose showed the most significant change in lung tissue. NSD2-regulated trehalose mainly affected ABC transporters, mineral absorption, protein digestion and absorption, metabolic pathways, and aminoacyl-tRNA biosynthesis. In conclusion, we reveal a new role of NSD2 in the pathogenesis of PAH related to the regulation of trehalose metabolism and autophagy via increasing the H3K36me2 level. NSD2 is a promising target for PAH therapy.

FoxO4 promotes myocardial ischemia-reperfusion injury: the role of oxidative stress-induced apoptosis.

Myocardial cell apoptosis is the main pathophysiological process underlying ischemia-reperfusion (I/R) injury. FoxO4, which was initially identified as a tumor suppressor that limits cell proliferation and induces apoptosis, plays diverse roles in cardiovascular diseases. However, its contribution to myocardial I/R injury remains unclear. The present study was undertaken to explore the role of FoxO4 in apoptosis during myocardial I/R injury and its underlying mechanisms in vivo. Rats were subjected to ligation/restoration of the left anterior descending branch of the coronary artery and 30 min of ischemia, followed by 4 h of reperfusion. Then, triphenyltetrazolium chloride (TTC) staining was performed to evaluate the infarct size. Transthoracic echocardiography was performed to evaluate cardiac function. Terminal deoxynucleotide transferase-mediated dUTP nick end-labeling (TUNEL) staining was performed to assess cell death in the myocardium. Real-time PCR was performed to measure FoxO4 mRNA expression. Western blots were performed to assess expression levels of the FoxO4 and cleaved caspase 3 proteins. Immunofluorescence staining was performed to measure cleaved caspase 3 expression levels. The hydroxylamine and TBA methods were performed to evaluate malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity, respectively. Dihydroethidium (DHE) staining was performed to measure reactive oxygen species (ROS) generation. We successfully established a rat model of myocardial I/R injury and observed an increase in FoxO4 expression in the myocardium. FoxO4 knockdown significantly protected rats from myocardial I/R injury, as indicated by a marked decrease in infarct sizes and improvements in cardiac function. Mechanistically, I/R induced excessive oxidative stress in rat hearts, most likely as a result of increased FoxO4 levels, and these effects contributed to inducing apoptosis. In conclusion, the FoxO4/ROS pathway represents a potentially novel mechanism underlying apoptosis during myocardial I/R injury. Therapeutic strategies targeting FoxO4 might represent new treatments for myocardial I/R injury.

A novel fibroblast growth factor-1 ligand with reduced heparin binding protects the heart against ischemia-reperfusion injury in the presence of heparin co-administration.

AIMS: Fibroblast growth factor 1 (FGF1), a heparin/heparan sulfate-binding growth factor, is a potent cardioprotective agent against myocardial infarction (MI). The impact of heparin, the standard of care for MI patients entering the emergency room, on cardioprotective effects of FGF1 is unknown, however. METHODS AND RESULTS: To address this, a rat model of MI was employed to compare cardioprotective potentials (lower infarct size and improve post-ischemic function) of native FGF1 and an engineered FGF1 (FGF1ΔHBS) with reduced heparin-binding affinity when given at the onset of reperfusion in the absence or presence of heparin. FGF1 and FGF1ΔHBS did not alter heparin's anticoagulant properties. Treatment with heparin alone or native FGF1 significantly reduced infarct size compared to saline (P < 0.05). Surprisingly, treatment with FGF1ΔHBS markedly lowered infarct size compared to FGF1 (P < 0.05). Both native and modified FGF1 restored contractile and relaxation function (P < 0.05 versus saline or heparin). Furthermore, FGF1ΔHBS had greater improvement in cardiac function compared to FGF1 (P < 0.05). Heparin negatively impacted the cardioprotective effects (infarct size, post-ischemic recovery of function) of FGF1 (P < 0.05) but not of FGF1ΔHBS. Heparin also reduced the biodistribution of FGF1, but not FGF1ΔHBS, to the left ventricle. FGF1 and FGF1ΔHBS bound and triggered FGFR1-induced downstream activation of ERK1/2 (P < 0.05); yet, heparin co-treatment decreased FGF1-produced ERK1/2 activation, but not that activated by FGF1ΔHBS. CONCLUSION: These findings demonstrate that modification of the heparin-binding region of FGF1 significantly improves the cardioprotective efficacy, even in the presence of heparin, identifying a novel FGF ligand available for therapeutic use in ischemic heart disease.

Pim-2 protects H9c2 cardiomyocytes from hypoxia/reoxygenation-induced apoptosis via downregulation of Bim expression.

We know that silencing Bim, a pro-apoptosis protein, significantly attenuates glucose and oxygen-deprived induced apoptosis in cardiomyocytes. However, the mechanisms underlying the regulation of the Bim activation in the heart have remained unknown. Pim-2 is one of three Pim serine/threonine kinase family members thought to be involved in cell survival and proliferation. H9c2 cardiomyocytes were subjected to a hypoxia/reoxygenation (H/R) condition in vitro, mimicking ischemic/reperfusion injury in vivo. H/R augmented the expression of Bim, Cyt C, and Pim-2 and induced H9c2 cell apoptosis. Overexpression of Pim-2 attenuated apoptosis which induced by H/R in H9c2 cells, via downregulation of Bim and Cyt C expression. Silencing of Pim-2 promoted H/R-induced apoptosis via upregulation of Bim and Cyt C expression. Co-IP revealed the interaction between Pim-2 and Bim protein, with Bim Ser65 phosphorylated by Pim-2. Furthermore, blocking proteasome activity by MG132 prevented Bim degradation, and Bim S65A mutation could reverse the anti-apoptotic role of Pim-2 which induced by H/R. These data demonstrated that Pim-2 is a novel Bim-interacting protein, which negatively regulates Bim degradation and protects H9c2 cardiomyocytes from H/R-induced apoptosis.

Pathogenesis, diagnosis and treatment of cerebral fat embolism.

In this study, we analyzed two cases of pure cerebral fat embolism and reviewed related literatures to explore the pathogenesis, clinical manifestations, diagnosis and treatment of cerebral fat embolism, improve the treatment efficiency and reduce the misdiagnosis rate. In our cases, patients fully returned to consciousness at the different times with good prognosis, normal vital signs and without obvious sequelae. For patients with the limb fractures, who developed coma without chest distress, dyspnea or other pulmonary symptoms 12 or 24 h post injury, cerebral fat embolism should be highly suspected, except for those with intracranial lesions, such as delayed traumatic intracerebral hemorrhage, etc. The early diagnosis and comprehensive treatment can improve prognosis.

Rapamycin protects cardiomyocytes against anoxia/reoxygenation injury by inducing autophagy through the PI3k/Akt pathway.

The purpose of this study was to investigate the potential cardioprotection roles of Rapamycin in anoxia/reoxygenation (A/R) injury of cardiomyocytes through inducing autophagy, and the involvement of PI3k/Akt pathway. We employed simulated A/R of neonatal rat ventricular myocytes (NRVM) as an in vitro model of ischemial/reperfusion (I/R) injury to the heart. NRVM were pretreated with four different concentrations of Rapamycin (20, 50, 100, 150 µmol/L), and pretreated with 10 mmol/L 3-methyladenine (3MA) for inhibiting autophagy during A/R. Then, Western blot analysis was used to examine variation in the expression of LC3-II, LC3-I, Bim, caspase-3, p-PI3KI, PI3KI, p-Akt and Akt. In our model, Rapamycin had a preferential action on autophagy, increasing the expression of LC3-II/LC3-I, whereas decreasing the expression of Bim and caspase-3. Moreover, our results also demonstrated that Rapamycin inhibited the activation of p-PI3KI and enhanced the activation of p-Akt. It is concluded that Rapamycin has a cardioprotection effect by inducing autophagy in a concentration-dependent manner against apopotosis through PI3K/Akt signaling pathway during A/R in NRVM.

BH3-only protein Bim is upregulated and mediates the apoptosis of cardiomyocytes under glucose and oxygen-deprivation conditions.

Bim is a potent pro-apoptotic BH3-only Bcl-2 member. However, the expression of Bim and its role in cardiac injury induced by ischemia remain unclear. H9c2 cells were subjected to a glucose and oxygen-deprived (GOD) condition in vitro, mimicking ischemia environment in vivo. GOD treatment augmented the expression of Bim and induced the apoptosis of H9c2 cells. Silencing of Bim by RNAi significantly attenuated GOD-induced cytotoxicity, suppressed mitochondrial membrane potential △Ψm loss, inhibited caspase 3 activation and reduced apoptosis. The data demonstrate that Bim is upregulated by GOD in a time-dependent manner in H9c2 cells, and enhances mitochondrial apoptosis dependent on the activation of caspase 3. Silencing of Bim may be a promising therapeutic strategy in ischemia related heart diseases.

How to interpret epicardial adipose tissue as a cause of coronary artery disease: a meta-analysis.

BACKGROUND: Experimental and clinical studies have suggested that epicardial adipose tissue (EAT) may cause coronary artery disease (CAD). A meta-analysis was conducted to investigate the relationship between EAT and CAD. METHODS: A systematic literature search of Cochrane, Medline, Pubmed, Elsevier, Springerlink, Ovid, and Embase from their respective inceptions to August 2011 was conducted using specific search terms such as 'epicardial adipose tissue' and 'epicardial fat'. Data were extracted from applicable articles and mean differences or risk ratio, including 95% confidence intervals (CI), were calculated using RevMan 5.1 software. RESULTS: A total of 15 case-control studies and one case-sectional study (N=2872 patients) were identified. Compared with the non-CAD group, EAT thickness and volume were significantly higher in the CAD group (mean difference 1.57 mm, 95% CI: 0.74, 2.40, P<0.00001; mean difference 15.22 ml, 95% CI: 7.58, 22.87, P<0.0001). Patients in the higher EAT tertile (≥ 100 ml) were more likely to have CAD compared with those in the lower EAT tertile (<100 ml) (risk ratio 0.69, 95% CI: 0.52, 0.92, P=0.01). Patients with coronary plaque also had increased EAT volume compared with patients without coronary plaque (mean difference 24.90 ml, 95% CI: 9.99, 39.81 P=0.001). EAT volume was not different in patients whose coronary artery calcium scores were less than or equal to 10 or greater than 10 (mean difference -17.28 ml, 95% CI: -52.01, 17.44, P=0.33). CONCLUSION: On the basis of the current evidence, EAT seems to be an effective marker in the prediction of CAD.