Abstract 87: Loss of Mir-155 Attenuates Sepsis Induced Cardiac Dysfunction

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Hui Wang ◽  
Yihua Bei ◽  
Jing Shi ◽  
Wei Sun ◽  
Peipei Huang ◽  
...  

Objective: Sepsis induced cardiac dysfunction is featured by inflammation and metabolic repression. miR-155 is a typical multifunctional miRNA and loss of miR-155 has been shown to protect the heart from pathological cardiac hypertrophy while increased miR-155 could promote the formation of foam cell in atherogenesis. However, the role of miR-155 in sepsis induced cardiac dysfunction is unclear. Methods: E.coli lipopolysaccharide (LPS) (5mg/kg) was administered to C57BL/6 mice to create a sepsis-induced cardiac dysfunction model. Cardiac function was assessed by echocardiography 5-6 h post-LPS administration. Heart tissues were collected within 7-9 h after LPS treatment for the analysis of gene expressions. Tail vein injection of miR-155 antagomir (80mg/kg/d) or miR-155 agomirs (30mg/kg/d) for 3 consecutive days were used to decrease or increase miR-155 expressions in heart. Results: LPS induced a reduction of 15% in fractional shortening (%FS) and 25% in ejection fraction (%EF). Expression of miR-155 was increased by 2 fold in sepsis-induced cardiac dysfunction mouse model. Over-expression of miR-155 agomirs led to a decrease of 5% in FS and 10% in EF as compared to scramble controls. Aggravation of LPS induced cardiac dysfunction by miR-155 agomir was not associated with alteration in inflammation or cardiac metabolism. However, miR-155 agomir increased LPS- induced myocardium apoptosis and also elevated the ratio of Bax/Bcl-2 at the protein level. Intravenous injection of cholesterol-modified antisense oligonucleorides antagomirs of miR-155 markedly rescued the LPS induced heart failure and apoptosis. Western bloting indicated that miR-155 overexpression in vivo led to a significant inhibition of Pea15a while miR-155 knock-down caused a significant upregulation of Pea15a, indicating that Pea15a was a potential target gene of miR-155. Interestingly, plasma miR-155 levels were also found to be significantly increased in critically ill patients with sepsis compared to healthy controls. Conclusion: This study demonstrates that miR-155 regulates sepsis induced cardiac dysfunction and Pea15a is a potential targer gene of miR-155. Loss of miR-155 represents a novel therapeutic method for sepsis induced cardiac dysfunction

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Hui Wang ◽  
Yihua Bei ◽  
Jing Shi ◽  
Wei Sun ◽  
Hui Liu ◽  
...  

Background: Sepsis-induced cardiac dysfunction is charactered by cardiac contractility dysfunction, myocardial inflammation and cardiac metabolism abnormal. Dysfunction of microRNAs (miRNAs, miRs) contributes to a variety of human diseases. However, their roles in sepsis-induced cardiac dysfunction are unclear. Methods and Results: Cardiac dysfunction was induced by E.coli lipopolysaccharide (LPS) administration in mice and 8 dysregulated miRNAs were identified by miRNA arrays. Among them, miR-21* was found to be increased most obviously as determined by quantitative reverse transcription polymerase chain reactions. Inhibition of miR-21* in vivo by antagomir attenuated the reduction of factional shortening (FS) and ejection fraction (EF) induced by LPS administration while forced over-expression of miR-21* in vivo by agomir accelerated LPS-induced cardiac dysfunction. Besides that, S100A8 and S100A9, two genes related to cardiac contractility were also found to be regulated in vivo by injection of miR-21* agomirs and antagomirs. Interestingly, cardiac inflammation indictors such as TNF-α and IL-6 and cardiac metabolism regulators including PPAR family, CD36, FATP, GLUT1, GLUT4, PDK4 were not changed by miR-21* in vivo. These data indicate that miR-21* controls sepsis-induced cardiac dysfunction by direct affecting cardiac contractility instead of cardiac inflammation and metabolism. SORBS2 was identified as a target gene of miR-21* and it was decreased by miR-21* agomir and increased by miR-21* antagomir in vivo. In consist with this, circulating levels of miR-21* were also increased in patients with sepsis compared with healthy controls. Conclusion: miR-21* controls sepsis-induced cardiac dysfunction by regulating SORBS2. Inhibition of miR-21* represents a novel therapeutic strategy for sepsis-induced cardiac dysfunction.


Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Hongliang Li ◽  
Peng Zhang

TRAF associated NF-κB activator (TANK) is adaptor protein which was identified as a negative regulator of TRAF-, TBK1- and IKKi-mediated signal transduction through its interaction with them. Besides its important roles in the regulation of immune response, it has been reported that TANK contributes to the development of autoimmune nephritis and osteoclastogenesis. However, its functions in cardiovascular diseases especially cardiac hypertrophy is largely unknown. In the present study, we interestingly observed that TNAK expression is increased by 240% in human hypertrophic cardiomyopathy(HCM)tissue and 320% in mouse hypertrophic heart after aortic banding (AB), indicating that TANK may be involved in the pathogenesis of this diseases. Subsequently, cardiac-specific TANK knockout (TANK-KO) and transgenic(TANK-TG)mice were generated and subjected to AB for 4 to 8 weeks. Our results demonstrated that TANK deficiency prevented against cardiac hypertrophy and fibrosis induced by pressure overload,as evidenced by that the cardiomyocytes enlargement and fibrosis formation was reduced by about 34% and 43% compared with WT mice, respectively. Conversely, TANK-TG mice showed an aggravated effect on cardiac hypertrophy in response to pressure overload with 36% and 47% increase of cardiomyocytes enlargement and fibrosis formation compared with non-transgenic mice. More importantly, in vitro experiments further revealed that TANK overexpression which was mediated by adenovirus in the cardiomyocytes dramatically increased the cell size and the expression of hypertrophic markers, whereas TANK knockdown had an opposite function. Mechanistically, we discovered that AKT signaling was activated (230%) in the hearts of TANK-TG mice, while being greatly reduced in TNAK-KO hearts after aortic banding. Moreover, blocking AKT/GSK3β signaling with a pharmacological AKT inhibitor reversed cardiac dysfunction of TANK-TG mice. Collectively, our data show that TNAK acts as a novel regulator of pathological cardiac hypertrophy and may be a promising therapeutic targets.


2019 ◽  
Author(s):  
Kerui Huang ◽  
Ting Miao ◽  
Kai Chang ◽  
Ping Kang ◽  
Qiuhan Jiang ◽  
...  

AbstractAge is a major risk factor for cardiovascular diseases. Currently, the non-autonomous regulation of age-related cardiac dysfunction is poorly understood. In the present study, we discover that age-dependent induction of cytokine unpaired 3 (Upd3) in Drosophila oenocytes (hepatocyte-like cells), due to a dampened peroxisomal import function, is the primary non-autonomous mechanism for elevated arrhythmicity in old hearts. We show that Upd3 is significantly up-regulated (52-fold) in aged oenocytes. Oenocyte-specific knockdown of Upd3 is sufficient to block aging-induced cardiac arrhythmia. We further show that the age-dependent induction of Upd3 is triggered by impaired peroxisomal import and elevated JNK signaling in aged oenocytes. Intriguingly, oenocyte-specific over-expression of Pex5, the key peroxisomal import receptor, restores peroxisomal import, blocks age-related Upd3 induction, and alleviates aging- and paraquat-induced cardiac arrhythmicity. Thus, our studies identify an important role of the evolutionarily conserved pro-inflammatory cytokine signaling and hepatocyte-specific peroxisomal import in mediating non-autonomous regulation of cardiac aging.


Hearts ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 117-125
Author(s):  
I. Tong Mak ◽  
Jay H. Kramer ◽  
Micaela Iantorno ◽  
Joanna J. Chmielinska ◽  
William B. Weglicki ◽  
...  

The role of NADPH oxidase subunit, gp91phox (NOX2) in development of oxidative stress and cardiac dysfunction due to iron (Fe)-overload was assessed. Control (C57BL/6J) and gp91phox knockout (KO) mice were treated for up to 8 weeks with Fe (2.5 mg/g/wk, i.p.) or Na-dextran; echocardiography, plasma 8-isoprostane (lipid peroxidation marker), cardiac Fe accumulation (Perl’s staining), and CD11b+ (WBCs) infiltrates were assessed. Fe caused no adverse effects on cardiac function at 3 weeks. At 6 weeks, significant declines in left ventricular (LV) ejection fraction (14.6% lower), and fractional shortening (19.6% lower) occurred in the Fe-treated control, but not in KO. Prolonging Fe treatment (8 weeks) maintained the depressed LV systolic function with a trend towards diastolic dysfunction (15.2% lower mitral valve E/A ratio) in controls but produced no impact on the KO. Fe-treatment (8 weeks) caused comparable cardiac Fe accumulation in both strains, but a 3.3-fold elevated plasma 8-isoprostane, and heightened CD11b+ staining in controls. In KO mice, lipid peroxidation and CD11b+ infiltration were 50% and 68% lower, respectively. Thus, gp91phox KO mice were significantly protected against oxidative stress, and systolic and diastolic dysfunction, supporting an important role of NOX2-mediated oxidative stress in causing cardiac dysfunction during Fe overload.


Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Hongliang Li ◽  
Xiao-Jing Zhang ◽  
Ke-Qiong Deng

Pathological cardiac hypertrophy, which is always accompanied by cardiac fibrosis and the resultant cardiac dysfunction, leads to hear failure and even sudden death. The TNF-receptor ubiquitous signaling and scaffolding protein (TRUSS) that is enriched in the heart has been identified as a negative regulator of cancer. However, the role of TRUSS in cardiac remodeling is unknown. Here, we aimed to investigate the potential participation of TRUSS in cardiac hypertrophy and the molecular events by which TRUSS regulates this pathological condition. The pathological cardiac hypertrophy model was established by pressure overload in vivo and Ang II stimulation in vitro . We observed that the expression level of TRUSS was dramatically increased in the heart and in primary cardiomyocytes upon pro-hypertrophic stimuli. To illustrate the functional role of TRUSS in cardiac remodeling, the cardiac specific knockout (KO) or transgenic (TG) mice were employed. After aortic binding (AB) for 4 weeks, TRUSS deficiency conferred significant resistance to pressure overload via significantly inhibiting cardiomyocytes enlargement and fibrosis formation by about 37% and 46%, respectively, whereas dramatically exacerbated hypertrophy, fibrosis, and cardiac dysfunction were shown in TRUSS-TG mice compared to their littermate controls. Mechanistically, TRUSS can directly bind to JNK, a well-known pro-hypertrophic factor, and activate its downstream pathway. Further investigations indicated that the aggravated effect of TRUSS on cardiac hypertrophy can be almost completely reversed by a specific JNK inhibitor, SP600125, indicating a JNK-dependent manner of TRUSS-regulated cardiac hypertrophy. The directly exacerbated function of TRUSS in cardiomyocytes and the JNK-dependent mechanisms were further validated in primary cardiomyocytes that treated with Ang II after infection with AdshTRUSS or AdTRUSS. Notably, the increased protein and mRNA expression of TRUSS was also observed in heart samples from patients with hypertrophic cardiac myopathy. In conclusion, TRUSS functions as a positive regulator of pathological cardiac hypertrophy, suggesting a promising therapeutic approach for the hypertrophy related heart diseases by balancing TRUSS expression.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Xia Zhang ◽  
Xiaohui Wang ◽  
Tuanzhu Ha ◽  
Li Liu ◽  
He Ma ◽  
...  

We have previously shown that increased expression of endothelial heat shock protein A12B (HSPA12B) attenuates LPS-induced cardiac dysfunction. MicroRNA-126 (miR-126) specifically targets adhesion molecules in endothelial cells. This study examined the role of miR-126 in HSPA12B-induced cardioprotection in sepsis. Endothelial HSPA12B-/- (n=6) and wild type (WT, n=6) mice were subjected to cecal ligation and puncture (CLP)-induced sepsis. Sham surgery served as sham control (n=6). Cardiac function was examined by echocardiography before and 6 h after CLP. CLP sepsis significantly decreased ejection fraction (EF%) by 34.8% and fractional shortening (%FS) by 43.1% in WT mice. EF% and FS% values in HSPA12B-/- septic mice showed further decreases of 19.9% and 22.5% compared with WT septic mice. The levels of ICAM1 and VCAM1 and the infiltration of immune cells (macrophages and neutrophils) into the myocardium of HSPA12B-/- septic mice were markedly greater than WT septic mice. The vascular permeability in HSPA12B-/- septic mice was much more severe than in WT septic mice. Importantly, the levels of circulating miR-126 in HSPA12B-/- septic mice were much lower than in WT septic mice. To examine whether decreased miR-126 is responsible for cardiac dysfunction in HSPA12B-/- septic mice, we loaded exosomes with miR-126 by transfection of bone marrow stromal cells with miR-126 mimics followed by isolation of exosomes 24 hours after transfection. Scrambled miR served as the miR control (miR-control). Exosomes loaded with miR-126 or miR-control were delivered into the myocardium through the right carotid artery immediately after induction of CLP (n=5-6/group). Cardiac function was significantly improved by delivery of miR-126 into the myocardium as evidenced by increased the values of EF% (51%) and FS% (59%), when compared with HSPA12B-/- septic mice. MiR-126 delivery significantly suppressed the expression of adhesion molecules, reduced immune cell infiltration in the myocardium, and improved vascular permeability in HSPA12B-/- septic mice. Delivery of miR-control did not alter cardiac dysfunction in HSPA12B-/- septic mice. We conclude that miR-126 plays a critical protective role in endothelial HSAP12B in preservation of cardiac function in sepsis.


Endocrinology ◽  
2013 ◽  
Vol 154 (10) ◽  
pp. 3937-3946 ◽  
Author(s):  
Eun-Gyoung Hong ◽  
Brian W. Kim ◽  
Dae Young Jung ◽  
Jong Hun Kim ◽  
Tim Yu ◽  
...  

Altered glucose metabolism in the heart is an important characteristic of cardiovascular and metabolic disease. Because thyroid hormones have major effects on peripheral metabolism, we examined the metabolic effects of heart-selective increase in T3 using transgenic mice expressing human type 2 iodothyronine deiodinase (D2) under the control of the α-myosin heavy chain promoter (MHC-D2). Hyperinsulinemic-euglycemic clamps showed normal whole-body glucose disposal but increased hepatic insulin action in MHC-D2 mice as compared to wild-type (WT) littermates. Insulin-stimulated glucose uptake in heart was not altered, but basal myocardial glucose metabolism was increased by more than two-fold in MHC-D2 mice. Myocardial lipid levels were also elevated in MHC-D2 mice, suggesting an overall up-regulation of cardiac metabolism in these mice. The effects of doxorubicin (DOX) treatment on cardiac function and structure were examined using M-mode echocardiography. DOX treatment caused a significant reduction in ventricular fractional shortening and resulted in more than 50% death in WT mice. In contrast, MHC-D2 mice showed increased survival rate after DOX treatment, and this was associated with a six-fold increase in myocardial glucose metabolism and improved cardiac function. Myocardial activity and expression of AMPK, GLUT1, and Akt were also elevated in MHC-D2 and WT mice following DOX treatment. Thus, our findings indicate an important role of thyroid hormone in cardiac metabolism and further suggest a protective role of glucose utilization in DOX-mediated cardiac dysfunction.


2011 ◽  
Vol 300 (4) ◽  
pp. H1274-H1281 ◽  
Author(s):  
Jean-François Jasmin ◽  
Giuseppe Rengo ◽  
Anastasios Lymperopoulos ◽  
Ratika Gupta ◽  
Gregory J. Eaton ◽  
...  

Caveolin (Cav)-1 has been involved in the pathogenesis of ischemic injuries. For instance, modulations of Cav-1 expression have been reported in animal models of myocardial infarction and cerebral ischemia-reperfusion. Furthermore, ablation of the Cav-1 gene in mice has been shown to increase the extent of ischemic injury in models of cerebral and hindlimb ischemia. Cav-1 has also been suggested to play a role in myocardial ischemic preconditioning. However, the role of Cav-1 in myocardial ischemia (MI)-induced cardiac dysfunction still remains to be determined. We determined the outcome of a permanent left anterior descending coronary artery (LAD) ligation in Cav-1 knockout (KO) mice. Wild-type (WT) and Cav-1 KO mice were subjected to permanent LAD ligation for 24 h. The progression of ischemic injury was monitored by echocardiography, hemodynamic measurements, 2,3,5-triphenyltetrazolium chloride staining, β-binding analysis, cAMP level measurements, and Western blot analyses. Cav-1 KO mice subjected to LAD ligation display reduced survival compared with WT mice. Despite similar infarct sizes, Cav-1 KO mice subjected to MI showed reduced left ventricular (LV) ejection fraction and fractional shortening as well as increased LV end-diastolic pressures compared with their WT counterparts. Mechanistically, Cav-1 KO mice subjected to MI exhibit reduced β-adrenergic receptor density at the plasma membrane as well as decreased cAMP levels and PKA phosphorylation. In conclusion, ablation of the Cav-1 gene exacerbates cardiac dysfunction and reduces survival in mice subjected to MI. Mechanistically, Cav-1 KO mice subjected to LAD ligation display abnormalities in β-adrenergic signaling.


Physiology ◽  
2006 ◽  
Vol 21 (4) ◽  
pp. 250-258 ◽  
Author(s):  
Sihem Boudina ◽  
E. Dale Abel

Cardiovascular disease is the primary cause of death in individuals with obesity and diabetes. However, the underlying mechanisms for cardiac dysfunction are partially understood. Studies have suggested that altered cardiac metabolism may play a role. The diabetic heart is characterized by increased fatty acid oxidation, increased myocardial oxygen consumption, and reduced cardiac efficiency. Here, we review possible mechanisms for reduced cardiac efficiency in obesity and diabetes by focusing on the potential role of mitochondrial uncoupling.


2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Vengadeshprabhu Karuppagounder ◽  
Somasundaram Arumugam ◽  
Remya Sreedhar ◽  
Vijayasree V Giridharan ◽  
Rejina Afrin ◽  
...  

Background: 14-3-3η family members are dimeric phosphoserine-binding proteins that participate in signal transduction and checkpoint control pathways. Anthracycline anticancer drug doxorubicin (Dox) can induce cardiotoxicity, which is believed to be based on inflammatory or oxidative injury. However, the role of 14-3-3η is not clear in Dox induced cardiac injury. We examined the role of 14-3-3η protein and apoptosis signal-regulating kinase-1 (Ask1) and inflammatory signaling by using transgenic mice with cardiac-specific expression of a dominant-negative 14-3-3η protein mutant (DN 14-3-3) in Dox induced cardiac injury. Methods: Cardiac dysfunction was induced by a single injection of Dox into wild-type (WT) and DN 14-3-3η mice. By the end of the study, echocardiography was performed to assess the cardiac function. The heart tissues were used for histopathology and western blotting. Results: Left ventricular (LV) fractional shortening and ejection fraction were dramatically decreased in DN 14-3-3η mice, when compared to WT mice after Dox injection. Inactivation of 14-3-3η protein significantly increased Dox induced mortality. Significant Ask1 activation in DN 14-3-3η after Dox injection was evidenced by pronounced de-phosphorylation at Ser-967 and intense immunofluorescence observed LV sections. Marked increase in myocardial apoptosis, cardiac hypertrophy, and fibrosis were observed with a corresponding up-regulation of proinflammatory factors and cytokine expression in DN 14-3-3η mice after Dox injection. Furthermore cardiac expression of high mobility group box (HMGB)1 and its cascade protein expressions were significantly up-regulated in DN 14-3-3η mice compared to WT mice after Dox injection. Conclusion: Taken together, these findings suggest that depletion of 14-3-3η protein causes reduce survival rate in mice with cardiac dysfunction, presumably via activation of downstream Ask1 signaling pathways. This may provide a novel therapeutic strategy against Dox-induced cardiac injury by regulating Ask1 signaling.


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