Abstract 51: Aldosterone Induces Cardiac Deleterious Effects Through A Grk2 And Grk5 Dependent Pathway

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Alessandro Cannavo ◽  
Daniela Liccardo ◽  
Sarah M Bass ◽  
Benjamin Woodall ◽  
Christopher J Traynham ◽  
...  

High Aldosterone (Aldo) plasma levels are present in heart failure patients and are associated with increased cardiac fibrosis and hypertrophy. These effects have been shown to be, in part, related to the transactivation of the angiotensin II receptor (AT1R), a G-protein coupled receptor (GPCR). In this regard, the GPCR kinase 2 (GRK2) and 5 (GRK5) are both critical regulators of cardiac function through GPCR regulation. Since these GRKs have also been shown to play a role in cardiac hypertrophy and HF development we investigated whether these kinases may play a role in myocardial Aldo signaling. To test this, we first treated neonatal rat ventricular cardiomyocytes (NRVMs) with Aldo (1 μM) and looked for GRK regulation. Following 12 hrs of Aldo-stimulation we observed a significant increase in both GRK2 and GRK5 protein levels. We also found that Aldo induced the localization of GRK2 to mitochondria, which the lab has previously found to occur following ischemic injury leading to increased cell death and mitochondrial dysfuntion. Indeed, high Aldo on NRVMs led to a significant increase in ROS generation and cell death, as observed by Mitosox Red and TUNEL staining, respectively. Notably, all these effects were abolished respectively by Spironolactone (Spiro, an Aldo receptor blocker) or Losartan (Los, an AT1R antagonist) pre-treatment. Next, in nuclear fractions, purified from Aldo-treated NRVMs, we observed a consistent increase in GRK5 nuclear localization that consequently induced a significant activation of hypertrophic genes, which is consistent with previous studies showing GRK5 being a key regulator of maladaptive cardiac hypertrophy after pressure-overload. Importantly, Spiro pre-treatment efficiently abolished these effects of GRK5. Finally, we treated wild-type mice in vivo with Aldo for two and four weeks and not only found that this induced significant cardiac hypertrophy and fibrosis compared to saline-treated mice, we also found significant increases in levels of GRK2 and GRK5. Therefore, our study provide, for the first time, data demonstrating that GRK2 and GRK5 are potential regulators of Aldo-mediated cardiac pathology acting either down-stream of mineralocorticoid receptor or transactivated AT1Rs.

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Yanfei Yang ◽  
Noritsugu Nakano ◽  
Junichi Sadoshima

Mst1 and Lats2, components of the mammalian Hippo pathway, stimulate apoptosis and inhibit hypertrophy of cardiomyocytes (CMs), thereby mediating reperfusion injury and heart failure. YAP, a transcription factor co-factor, is negatively regulated by the Hippo pathway, and controls cell survival, proliferation and tissue regeneration. The role of YAP in regulating growth and death of CMs is poorly understood. YAP overexpression in CMs induced cardiac hypertrophy, as indicated by increases in cell size (+1.2 fold, p<0.01), protein content (+1.1 fold, p<0.01) and ANF (luciferase reporter activity +1.7 fold, mRNA +2.2 fold, and staining +2.7 fold, p<0.01). Lats2 phosphorylates YAP at Serine 127, which induces cytoplasmic translocation of YAP, whereas YAP(S127A) is localized constitutively in the nucleus. Expression of YAP(S127A) enhanced hypertrophy in cultured CMs compared to that of wild type YAP (+1.87 fold ANF staining, p<0.05), suggesting that the Mst1/Hippo pathway negatively regulates cardiac hypertrophy through YAP. YAP inhibited cell death induced by H2O2 treatment, as evaluated with TUNEL staining (-65%, p<0.05) and CellTiter Blue assays (+34.9%, p<0.01), indicating that YAP plays an essential role in mediating CM survival. Interestingly, YAP also significantly increased Ki67 positive cells in cultured CMs compared to LacZ (+2.65 fold, p<0.05). We used a mouse model of chronic myocardial infarction (MI) to evaluate the function of YAP in the heart in vivo. Although YAP is diffusely localized both in the nucleus and cytosol in CMs in control hearts, CMs in the border zone of MI exhibited nuclear localization of YAP whereas YAP was excluded from the nucleus in CMs in the remodeling area four days after MI (+6.52 fold and +1.28 fold). Some of the YAP positive CMs in the border zone exhibited positive co-staining with Ki67, suggesting that YAP potentially induces CM proliferation. A significant increase in nuclear YAP and Ki67 positive CMs (+2.95 fold, p<0.01 and +2.18 fold, p<0.05) was also observed in neonatal rat hearts whose apex was surgically resected three days before euthanasia. These results suggest that YAP plays an important role in mediating not only hypertrophy and survival, but also proliferation of CMs in response to myocardial injury.


2008 ◽  
Vol 295 (1) ◽  
pp. H314-H326 ◽  
Author(s):  
Santhosh K. Mani ◽  
Hirokazu Shiraishi ◽  
Sundaravadivel Balasubramanian ◽  
Kentaro Yamane ◽  
Meenakshi Chellaiah ◽  
...  

Calpain activation is linked to the cleavage of several cytoskeletal proteins and could be an important contributor to the loss of cardiomyocytes and contractile dysfunction during cardiac pressure overload (PO). Using a feline right ventricular (RV) PO model, we analyzed calpain activation during the early compensatory period of cardiac hypertrophy. Calpain enrichment and its increased activity with a reduced calpastatin level were observed in 24- to 48-h-PO myocardium, and these changes returned to basal level by 1 wk of PO. Histochemical studies in 24-h-PO myocardium revealed the presence of TdT-mediated dUTP nick-end label (TUNEL)-positive cardiomyocytes, which exhibited enrichment of calpain and gelsolin. Biochemical studies showed an increase in histone H2B phosphorylation and cytoskeletal binding and cleavage of gelsolin, which indicate programmed cardiomyocyte cell death. To test whether calpain inhibition could prevent these changes, we administered calpeptin (0.6 mg/kg iv) by bolus injections twice, 15 min before and 6 h after induction of 24-h PO. Calpeptin blocked the following PO-induced changes: calpain enrichment and activation, decreased calpastatin level, caspase-3 activation, enrichment and cleavage of gelsolin, TUNEL staining, and histone H2B phosphorylation. Although similar administration of a caspase inhibitor, N-benzoylcarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VD-fmk), blocked caspase-3 activation, it did not alleviate other aforementioned changes. These results indicate that biochemical markers of cardiomyocyte cell death, such as sarcomeric disarray, gelsolin cleavage, and TUNEL-positive nuclei, are mediated, at least in part, by calpain and that calpeptin may serve as a potential therapeutic agent to prevent cardiomyocyte loss and preserve myocardial structure and function during cardiac hypertrophy.


2017 ◽  
Vol 43 (6) ◽  
pp. 2253-2263 ◽  
Author(s):  
Yuan Liu ◽  
Lu Gao ◽  
Sen Guo ◽  
Yuzhou Liu ◽  
Xiaoyan Zhao ◽  
...  

Background/Aims: Endothelial-to-mesenchymal transition (EndMT) is a mechanism that promotes cardiac fibrosis induced by Angiotensin II (AngII). Kaempferol (KAE) is a monomer component mainly derived from the rhizome of Kaempferia galanga L. It shows anti-inflammatory, anti-oxidative, anti-microbial and anti-cancer properties, which can be used in the treatment of cancer, cardiovascular diseases, infection, etc. But, its effects on the development of cardiac remodelling remain completely unknown. The aim of the present study was to determine whether KAE attenuates cardiac hypertrophy induced by angiotensin II (Ang II) in cultured neonatal rat cardiac myocytes in vitro and cardiac hypertrophy induced by AngII infusion in mice in vivo. Methods: Male wild-type mice aged 8-10 weeks with or without KAE were subjected to AngII or saline, to induce fibrosis or as a control, respectively. Morphological changes, echocardiographic parameters, histological analyses, and hypertrophic markers were also used to evaluate hypertrophy. Results: KAE prevented and reversed cardiac remodelling induced by AngII. The KAE in this model exerted no basal effects but attenuated cardiac fibrosis, hypertrophy and dysfunction induced by AngII. Both in vivo and in vitro experiments demonstrated that Ang II infusion or TGF-β induced EndMT can be reduced by KAE and the proliferation and activation of cardiac fibroblasts (CFs) can be inhibited by KAE. Conclusions: The results suggest that KAE prevents and reverses ventricular fibrosis and cardiac dysfunction, providing an experimental basis for clinical treatment on ventricular fibrosis.


2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Yasuhide Kuwabara ◽  
Takahiro Horie ◽  
Osamu Baba ◽  
Toru Kita ◽  
Takeshi Kimura ◽  
...  

Rationale: In some type 2 diabetes mellitus (T2D) patients without hypertension, cardiac hypertrophy and attenuated cardiac function are observed, and this insult is termed “diabetic cardiomyopathy.” Tons of evidence suggests that microRNAs are involved in cardiac diseases. However, the functions of microRNAs in the diabetic cardiomyopathy induced by T2D and obesity are not fully understood. Methods and Results: C57BL/6 mice were fed a high-fat diet (HFD) for 20 weeks, which induced obesity and T2D. MicroRNA microarray and real-time PCR revealed that miR-451 levels were significantly increased in the T2D mouse hearts (n=4-5, p<0.05). Because excess supply of saturated fatty acids is a cause of diabetic cardiomyopathy, we stimulated neonatal rat cardiac myocytes (NRCMs) with palmitate in physiological albumin concentration and confirmed that miR-451 expression was increased in a dose-dependent manner (n=6-12, p<0.01). Loss of miR-451 function ameliorated palmitate-induced lipotoxicity in NRCMs (n=4, p<0.05). Calcium-binding protein 39 (Cab39) is a scaffold protein of liver kinase B1 (LKB1), an upstream kinase of AMP-activated protein kinase (AMPK). Cab39 was a direct target of miR-451 in NRCMs and Cab39 overexpression rescued the palmitate-induced lipotoxicity in NRCMs (n=4, p<0.01). To clarify miR-451 functions in vivo, we generated cardiomyocyte-specific miR-451 knockout (cKO) mice. HFD-induced cardiac hypertrophy and contractile reserves were ameliorated in cKO mice compared with HFD-fed control mice. Protein levels of Cab39 and phosphorylated AMPK were increased and phosphorylated mammalian target of rapamycin (mTOR) was reduced in HFD-fed cKO mouse hearts compared with HFD-fed control mouse hearts (n=10-12, p<0.05). We also measured the lipotoxic intermediates, triglyceride and ceramide, in these mouse hearts using HPLC-evaporative light scattering detector (ELSD). Although there was no difference in triglyceride levels (n=3-5), ceramide level was decreased in HFD-fed cKO mice compared with HFD-fed control mice (n=3-5, p<0.05). Conclusions: Our results indicate that miR-451 exacerbates diabetic cardiomyopathy. miR-451 is a potential therapeutic target for cardiac disease caused by T2D and obesity.


2018 ◽  
Author(s):  
Hongying Fan ◽  
Ruqin Lin ◽  
Zhenhui Chen ◽  
Xingyu Leng ◽  
Xianbo Wu ◽  
...  

AbstractCronobacter sakazakii (CS), an important pathogen, is associated with the development of necrotizing enterocolitis (NEC), infant sepsis, and meningitis. Several randomized prospective clinical trials demonstrated that oral probiotics could decrease the incidence of NEC. Previously, we isolated and characterized a novel probiotic, B. fragilis strain ZY-312. However, it remains unclear how ZY-312 protects the host from the effects of CS infection. To understand the underlying mechanisms triggering the probiotic effects, we tested the hypothesis that there was a cross-talk between probiotics/probiotics-modulated microbiota and the local immune system, governed by the permeability of the intestinal mucosa using in vitro and in vivo models for the intestinal permeability. The probiotic effects of ZY-312 on intestinal epithelial cells were first examined, which revealed that ZY-312 inhibited CS invasion, CS-induced dual cell death (pyroptosis and apoptosis), and epithelial barrier dysfunction in vitro and in vivo. ZY-312 also decreased the expression of an inflammasome (NOD-like receptor family member pyrin domain-containing protein 3 (NLRP3), caspase-3, and serine protease caspase-1 in a neonatal rat model. Furthermore, ZY-312 significantly modulated the compositions of the intestinal bacterial communities, and decreased the relative abundances of Proteobacteria, Gamma proteobacteria, but increased the relative abundance of Bacteroides and Bacillus in neonatal rats. In conclusion, our findings have shown for the first time that the probiotic, B. fragilis ZY-312, suppresses CS-induced NEC by modulating the pro-inflammatory response and dual cell death (apoptosis and pyroptosis).Author summaryCronobacter sakazakii, a major necrotizing enterocolitis pathogen, is used as a model microorganism for the study of opportunistic bacteria in the pathogenesis of necrotizing enterocolitis. Here, we have now unequivocally demonstrated that both apoptotic and pyroptotic stimuli contribute to the pathogenesis of Cronobacter sakazakii -induced necrotizing enterocolitis. Previously, we isolated and characterized a novel probiotic, B. fragilis strain ZY-312. We found that the ZY-312 defense against Cronobacter sakazakii-induced necrotizing enterocolitis by inhibiting Cronobacter sakazakii invasion, epithelial barrier dysfunction, the expression of inflammatory cytokines and dual cell death (pyroptosis and apoptosis). This study demonstrates the utility of ZY-312 as a promising probiotic agent for the prevention and treatment of various intestinal diseases, including NEC.


2018 ◽  
Vol 132 (6) ◽  
pp. 685-699 ◽  
Author(s):  
Zhen-Guo Ma ◽  
Xin Zhang ◽  
Yu-Pei Yuan ◽  
Ya-Ge Jin ◽  
Ning Li ◽  
...  

T-cell infiltration and the subsequent increased intracardial chronic inflammation play crucial roles in the development of cardiac hypertrophy and heart failure (HF). A77 1726, the active metabolite of leflunomide, has been reported to have powerful anti-inflammatory and T cell-inhibiting properties. However, the effect of A77 1726 on cardiac hypertrophy remains completely unknown. Herein, we found that A77 1726 treatment attenuated pressure overload or angiotensin II (Ang II)-induced cardiac hypertrophy in vivo, as well as agonist-induced hypertrophic response of cardiomyocytes in vitro. In addition, we showed that A77 1726 administration prevented induction of cardiac fibrosis by inhibiting cardiac fibroblast (CF) transformation into myofibroblast. Surprisingly, we found that the protective effect of A77 1726 was not dependent on its T lymphocyte-inhibiting property. A77 1726 suppressed the activation of protein kinase B (AKT) signaling pathway, and overexpression of constitutively active AKT completely abolished A77 1726-mediated cardioprotective effects in vivo and in vitro. Pretreatment with siRNA targetting Fyn (si Fyn) blunted the protective effect elicited by A77 1726 in vitro. More importantly, A77 1726 was capable of blocking pre-established cardiac hypertrophy in mice. In conclusion, A77 1726 attenuated cardiac hypertrophy and cardiac fibrosis via inhibiting FYN/AKT signaling pathway.


2016 ◽  
Vol 38 (4) ◽  
pp. 1553-1562 ◽  
Author(s):  
Yan Lin ◽  
Xiaojie Zhang ◽  
Wei Xiao ◽  
Bo Li ◽  
Jun Wang ◽  
...  

Background/Aims: Studies performed in experimental animals have shown that polyamines contribute to several physiological and pathological processes, including cardiac hypertrophy. This involves an increase in ornithine decarboxylase (ODC) activity and intracellular polyamines associated with regulation of gene expression. Difluoromethylornithine (DFMO), an irreversible inhibitor of ODC, has attracted considerable interest for its antiproliferative role, which it exerts through inhibition of the polyamine pathway and cell turnover. Whether DFMO attenuates cardiac hypertrophy through endoplasmic reticulum stress (ERS) is unclear. Methods: Myocardial hypertrophy was simulated by isoproterenol (ISO). Polyamine depletion was achieved using DFMO. Hypertrophy was estimated using the heart/body index and atrial natriuretic peptide (ANP) gene expression. Cardiac fibrosis and apoptosis were measured by Masson and TUNEL staining. Expression of ODC and spermidine/spermine N1-acetyltransferase (SSAT) were analyzed via real-time PCR and Western blot analysis. Protein expression of ERS and apoptosis factors were analyzed using Western blot analysis. Results: DFMO treatments significantly attenuated hypertrophy and apoptosis induced by ISO in cardiomyocytes. DFMO down-regulated the expression of ODC, glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), cleaved caspase-12, and Bax and up-regulated the expression of SSAT and Bcl-2. Finally, these changes were partially reversed by the addition of exogenous putrescine. Conclusion: The data presented here suggest that polyamine depletion could inhibit cardiac hypertrophy and apoptosis, which is closely related to the ERS pathway.


2017 ◽  
Vol 44 (3) ◽  
pp. 1011-1023 ◽  
Author(s):  
Hui Liu ◽  
Xibo Jing ◽  
Aiqiao Dong ◽  
Baobao Bai ◽  
Haiyan Wang

Background/Aims: Myocardial ischemia/reperfusion (I/R) injury remains a great challenge in clinical therapy. Tissue inhibitor of metalloproteinases 3 (TIMP3) plays a crucial role in heart physiological and pathophysiological processes. However, the effects of TIMP3 on I/R injury remain unknown. Methods: C57BL/6 mice were infected with TIMP3 adenovirus by local delivery in myocardium followed by I/R operation or doxorubicin treatment. Neonatal rat cardiomyocytes were pretreated with TIMP3 adenovirus prior to anoxia/reoxygenation (A/R) treatment in vitro. Histology, echocardiography, in vivo phenotypical analysis, flow cytometry and western blotting were used to investigate the altered cardiac function and underlying mechanisms. Results: The results showed that upregulation of TIMP3 in myocardium markedly inhibited myocardial infarct areas and the cardiac dysfunction induced by I/R or by doxorubicin treatment. TUNEL staining revealed that TIMP3 overexpression attenuated I/R-induced myocardial apoptosis, accompanied by decreased Bax/Bcl-2 ratio, Cleaved Caspase-3 and Cleaved Caspase-9 expression. In vitro, A/R-induced cardiomyocyte apoptosis was abrogated by pharmacological inhibition of reactive oxygen species (ROS) production or MAPKs signaling. Attenuation of ROS production reversed A/R-induced MAPKs activation, whereas MAPKs inhibitors showed on effect on ROS production. Furthermore, in vivo or in vitro overexpression of TIMP3 significantly inhibited I/R- or A/R-induced ROS production and MAPKs activation. Conclusion: Our findings demonstrate that TIMP3 upregulation protects against cardiac I/R injury through inhibiting myocardial apoptosis. The mechanism may be related to inhibition of ROS-initiated MAPKs pathway. This study suggests that TIMP3 may be a potential therapeutic target for the treatment of I/R injury.


2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
M. Gokila Vani ◽  
K. J. Senthil Kumar ◽  
Jiunn-Wang Liao ◽  
Shih-Chang Chien ◽  
Jeng-Leun Mau ◽  
...  

In this study, we investigated the cytoprotective effects of antcin C, a steroid-like compound isolated from Antrodia cinnamaomea against AAPH-induced oxidative stress and apoptosis in human hepatic HepG2 cells. Pretreatment with antcin C significantly protects hepatic cells from AAPH-induced cell death through the inhibition of ROS generation. Furthermore, AAPH-induced lipid peroxidation, ALT/AST secretion and GSH depletion was significantly inhibited by antcin C. The antioxidant potential of antcin C was correlated with induction of antioxidant genes including, HO-1, NQO-1,γ-GCLC, and SODviatranscriptional activation of Nrf2. The Nrf2 activation by antcin C is mediated by JNK1/2 and PI3K activation, whereas pharmacologic inhibition of JNK1/2 and PI3K abolished antcin C-induced Nrf2 activity. In addition, AAPH-induced apoptosis was significantly inhibited by antcin C through the down-regulation of pro-apoptotic factors including, Bax, cytochrome c, capase 9, -4, -12, -3, and PARP.In vivostudies also show that antcin C significantly protected mice liver from AAPH-induced hepatic injury as evidenced by reduction in hepatic enzymes in circulation. Further, immunocytochemistry analyses showed that antcin C significantly increased HO-1 and Nrf2 expression in mice liver tissues. These results strongly suggest that antcin C could protect liver cells from oxidative stress and cell deathviaNrf2/ARE activation.


2020 ◽  
Vol 40 (11) ◽  
Author(s):  
Maomao Gao ◽  
Fengjiao Hu ◽  
Manli Hu ◽  
Yufeng Hu ◽  
Hongjie Shi ◽  
...  

Abstract Aim: The study aims to evaluate protective effects of sophoricoside (Sop) on cardiac hypertrophy. Meanwhile, the potential and significance of Sop should be broadened and it should be considered as an attractive drug for the treatment of pathological cardiac hypertrophy and heart failure. Methods: Using the phenylephrine (PE)-induced neonatal rat cardiomyocytes (NRCMs) enlargement model, the potent protection of Sop against cardiomyocytes enlargement was evaluated. The function of Sop was validated in mice received transverse aortic coarctation (TAC) or sham surgery. At 1 week after TAC surgery, mice were treated with Sop for the following 4 weeks, the hearts were harvested after echocardiography examination. Results: Our study revealed that Sop significantly mitigated TAC-induced heart dysfunction, cardiomyocyte hypertrophy and cardiac fibrosis. Mechanistically, Sop treatment induced a remarkable activation of AMPK/mTORC1-autophagy cascade following sustained hypertrophic stimulation. Importantly, the protective effect of Sop was largely abolished by the AMPKα inhibitor Compound C, suggesting an AMPK activation-dependent manner of Sop function on suppressing pathological cardiac hypertrophy. Conclusion: Sop ameliorates cardiac hypertrophy by activating AMPK/mTORC1-mediated autophagy. Hence, Sop might be an attractive candidate for the treatment of pathological cardiac hypertrophy and heart failure.


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