Redox regulation of MAPK pathways and cardiac hypertrophy in adult rat cardiac myocyte

Mapping cardiac remodeling in chronic kidney disease

Patients with advanced chronic kidney disease (CKD) mostly die from sudden cardiac death and recurrent heart failure. The mechanisms of cardiac remodeling are largely unclear. To dissect molecular and cellular mechanisms of cardiac remodeling in CKD in an unbiased fashion, we performed left ventricular single-nuclear RNA sequencing in two mouse models of CKD. Our data showed a hypertrophic response trajectory of cardiomyocytes with stress signaling and metabolic changes driven by soluble uremia-related factors. We mapped fibroblast to myofibroblast differentiation in this process and identified notable changes in the cardiac vasculature, suggesting inflammation and dysfunction. An integrated analysis of cardiac cellular responses to uremic toxins pointed toward endothelin-1 and methylglyoxal being involved in capillary dysfunction and TNFα driving cardiomyocyte hypertrophy in CKD, which was validated in vitro and in vivo. TNFα inhibition in vivo ameliorated the cardiac phenotype in CKD. Thus, interventional approaches directed against uremic toxins, such as TNFα, hold promise to ameliorate cardiac remodeling in CKD.

Sesamin suppresses angiotensin-II-enhanced oxidative stress and hypertrophic markers in H9c2 cells

Myocardial hypertrophy plays a crucial role in cardiovascular disease (CVD) development. Myocardial hypertrophy is an adaptive response by myocardial cells to stress after cardiac injury to maintain cardiac output and function. Angiotensin II (Ang-II) regulates CVD through the renin-angiotensin-aldosterone system, and its signaling in cardiac myocytes leads to excessive reactive oxygen species (ROS) production, oxidative stress, and inflammation. Sesamin (SA), a natural compound in sesame seeds, has anti-inflammatory and anti-apoptotic effects. This study investigated whether SA could attenuate hypertrophic damage and oxidative injuries in H9c2 cells under Ang-II stimulation. We found that SA decreased the cell surface area. Furthermore, Ang-II treatment reduced Ang-II-increased ANP, BNP, and β-MHC expression. Ang-II enhanced NADPH oxidase activity, ROS formation, and decreased Superoxide Dismutase (SOD) activity. SA treatment reduces Ang-II-caused oxidative injuries. We also found that SA mitigates Ang-II-induced apoptosis and pro-inflammatory responses. In conclusion, SA could attenuate Ang-II-induced cardiac hypertrophic injuries by inhibiting oxidative stress, apoptosis, and inflammation in H9c2 cells. Therefore, SA might be a potential supplement for CVD management.

Promising Therapeutic Treatments for Cardiac Fibrosis: Herbal Plants and Their Extracts

Cardiac fibrosis is closely associated with multiple heart diseases, which are a prominent health issue in the global world. Neurohormones and cytokines play indispensable roles in cardiac fibrosis. Many signaling pathways participate in cardiac fibrosis as well. Cardiac fibrosis is due to impaired degradation of collagen and impaired fibroblast activation, and collagen accumulation results in increasing heart stiffness and inharmonious activity, leading to structure alterations and finally cardiac function decline. Herbal plants have been applied in traditional medicines for thousands of years. Because of their naturality, they have attracted much attention for use in resisting cardiac fibrosis in recent years. This review sheds light on several extracts from herbal plants, which are promising therapeutics for reversing cardiac fibrosis.

The Impact of Pharmacotherapy for Heart Failure on Oxidative Stress-Role of New Drugs, Flozins

Heart failure (HF) is a multifactorial clinical syndrome involving many complex processes. The causes may be related to abnormal heart structure and/or function. Changes in the renin-angiotensin-aldosterone system, the sympathetic nervous system, and the natriuretic peptide system are important in the pathophysiology of HF. Dysregulation or overexpression of these processes leads to changes in cardiac preload and afterload, changes in the vascular system, peripheral vascular dysfunction and remodeling, and endothelial dysfunction. One of the important factors responsible for the development of heart failure at the cellular level is oxidative stress. This condition leads to deleterious cellular effects as increased levels of free radicals gradually disrupt the state of equilibrium, and, as a consequence, the internal antioxidant defense system is damaged. This review focuses on pharmacotherapy for chronic heart failure with regard to oxidation-reduction metabolism, with special attention paid to the latest group of drugs, SGLT2 inhibitors-an integral part of HF treatment. These drugs have been shown to have beneficial effects by protecting the antioxidant system at the cellular level.

Secretoneurin as a Novel Biomarker of Cardiovascular Episodes: Are We There Yet? A Narrative Review

Secretoneurin (SN) is a 33 amino-acid evolutionary conserved neuropeptide from the chromogranin peptide family. SN's main effects may be cardioprotective and are believed to be mediated through its inhibition of calmodulin-dependent kinase II (CaMKII), which influences intracellular calcium handling. SN inhibition of CaMKII suppresses calcium leakage from the sarcoplasmic reticulum through the ryanodine receptor. This action may reduce the risk of ventricular arrhythmias and calcium-dependent remodelling in heart failure. SN is also involved in reducing the intracellular reactive oxygen species concentration, modulating the immune response, and regulating the cell cycle, including apoptosis. SN can predict mortality in different disease states, beyond the classical risk factors and markers of myocardial injury. Plasma SN levels are elevated soon after an arrhythmogenic episode. In summary, SN is a novel biomarker with potential in cardiovascular medicine, and probably beyond.

Prediction of Major Adverse Cardiovascular Events in Patients With Hypertrophic Cardiomyopathy Using Proteomics Profiling

BACKGROUND

Hypertrophic cardiomyopathy often causes major adverse cardiovascular events (MACE), for example, arrhythmias, stroke, heart failure, and sudden cardiac death. Currently, there are no models available to predict MACE. Furthermore, it remains unclear which signaling pathways mediate MACE. Therefore, we aimed to prospectively determine protein biomarkers that predict MACE in hypertrophic cardiomyopathy and to identify signaling pathways differentially regulated in patients who subsequently develop MACE.

METHODS

In this multi-centre prospective cohort study of patients with hypertrophic cardiomyopathy, we conducted plasma proteomics profiling of 4979 proteins upon enrollment. We developed a proteomics-based model to predict MACE using data from one institution (training set). We tested the predictive ability in independent samples from the other institution (test set) and performed time-to-event analysis. Additionally, we executed pathway analysis of predictive proteins using a false discovery rate threshold of <0.001.

RESULTS

The study included 245 patients (n=174 in the training set and n=71 in the test set). Using the proteomics-based model to predict MACE derived from the training set, the area under the receiver-operating-characteristic curve was 0.81 (95% CI, 0.68-0.93) in the test set. In the test set, the high-risk group determined by the proteomics-based predictive model had a significantly higher rate of developing MACE (hazard ratio, 13.6 [95% CI, 1.7-107]; P=0.01). The Ras-MAPK (mitogen-activated protein kinase) pathway was upregulated in patients who subsequently developed MACE (false discovery rate<1.0×10-7). Pathways involved in inflammation and fibrosis-for example, the TGF (transforming growth factor)-β pathway-were also upregulated.

CONCLUSIONS

This study serves as the first to demonstrate the ability of proteomics profiling to predict MACE in hypertrophic cardiomyopathy, exhibiting both novel (eg, Ras-MAPK) and known (eg, TGF-β) pathways differentially regulated in patients who subsequently experience MACE.

Characterization and Validation of ceRNA-Mediated Pathway–Pathway Crosstalk Networks Across Eight Major Cardiovascular Diseases

Pathway analysis is considered as an important strategy to reveal the underlying mechanisms of diseases. Pathways that are involved in crosstalk can regulate each other and co-regulate downstream biological processes. Furthermore, some genes in the pathways can function with other genes via the relationship of the competing endogenous RNA (ceRNA) mechanism, which has also been demonstrated to play key roles in cellular biology. However, the comprehensive analysis of ceRNA-mediated pathway crosstalk is lacking. Here, we constructed the landscape of the ceRNA-mediated pathway–pathway crosstalk of eight major cardiovascular diseases (CVDs) based on sequencing data from ∼2,800 samples. Some common features shared by numerous CVDs were uncovered. A fraction of the pathway–pathway crosstalk was conserved in multiple CVDs and a core pathway–pathway crosstalk network was identified, suggesting the similarity of pathway–pathway crosstalk among CVDs. Experimental evidence also demonstrated that the pathway crosstalk was functioned in CVDs. We split all hub pathways of each pathway–pathway crosstalk network into three categories, namely, common hubs, differential hubs, and specific hubs, which could highlight the common or specific biological mechanisms. Importantly, after a comparison analysis of the hub pathways of networks, ∼480 hub pathway-induced common modules were identified to exert functions in CVDs broadly. Moreover, we performed a random walk algorithm on the hub pathway-induced sub-network and identified 23 potentially novel CVD-related pathways. In summary, our study revealed the potential molecular regulatory mechanisms of ceRNA crosstalk in pathway–pathway crosstalk levels and provided a novel routine to investigate the pathway–pathway crosstalk in cardiology. All CVD pathway–pathway crosstalks are provided in http://www.licpathway.net/cepathway/index.html.

RNA-binding protein CELF1 promotes cardiac hypertrophy via interaction with PEBP1 in cardiomyocytes

Cardiac hypertrophy is considered as a common pathophysiological process in various cardiovascular diseases. CUG triplet repeat-binding protein 1 (CELF1) is an RNA-binding protein that has been shown to be an important post-transcription regulator and involved in several types of cancer, whereas its role in cardiac remodeling remains unclear. Herein, we found that the expression of CELF1 was significantly increased in pressure overload-induced hypertrophic hearts and angiotensin II (Ang II)-induced neonatal cardiomyocytes. Based on transverse aortic constriction-induced cardiac hypertrophy model, CELF1 deficiency markedly ameliorated cardiac hypertrophy, cardiac fibrosis, oxidative stress, and apoptosis. Accordingly, CELF1 deficiency alleviated the production of reactive oxygen species (ROS) and apoptosis of neonatal cardiomyocytes via inhibition of Raf1, TAK1, ERK1/2, and p38 phosphorylation. Mechanistically, depletion or overexpression of CELF1 negatively regulated the protein expression of phosphatidylethanolamine-binding protein 1 (PEBP1), while the mRNA expression of PEBP1 remained unchanged. RNA immunoprecipitation revealed that CELF1 directly interacted with PEBP1 mRNA. Biotin pull-down analysis and dual-luciferase assay showed that CELF1 directly bound to the fragment 1 within 3'UTR of PEBP1. Moreover, knockdown of PEBP1 partially enhanced the production of ROS and apoptosis of neonatal cardiomyocytes inhibited by CELF1 deficiency. In conclusion, CELF1 binds to the 3'UTR of PEBP1 and acts as an endogenous activator of MAPK signaling pathway. Inhibition of CELF1 attenuates pathological cardiac hypertrophy, oxidative stress, and apoptosis, thus could be a potential therapeutic strategy of pathological cardiac hypertrophy.

UCP3 (Uncoupling Protein 3) Insufficiency Exacerbates Left Ventricular Diastolic Dysfunction During Angiotensin II-Induced Hypertension

Background

Left ventricular diastolic dysfunction, an early stage in the pathogenesis of heart failure with preserved ejection fraction, is exacerbated by joint exposure to hypertension and obesity; however, the molecular mechanisms involved remain uncertain. The mitochondrial UCP3 (uncoupling protein 3) is downregulated in the heart with obesity. Here, we used a rat model of UCP3 haploinsufficiency (ucp3^+/‐) to test the hypothesis that decreased UCP3 promotes left ventricular diastolic dysfunction during hypertension.

Methods and Results

Ucp3^+/‐ rats and ucp3^+/+ littermates fed a high‐salt diet (HS; 2% NaCl) and treated with angiotensin II (190 ng/kg per min for 28 days) experienced a similar rise in blood pressure (158±4 versus 155±7 mm Hg). However, UCP3 insufficiency worsened diastolic dysfunction according to echocardiographic assessment of left ventricular filling pressures (E/e’; 18.8±1.0 versus 14.9±0.6; P<0.05) and the isovolumic relaxation time (24.7±0.6 versus 21.3±0.5 ms; P<0.05), as well as invasive monitoring of the diastolic time constant (Tau; 15.5±0.8 versus 12.7±0.2 ms; P<0.05). Exercise tolerance on a treadmill also decreased for HS/angiotensin II‐treated ucp3^+/‐ rats. Histological and molecular analyses further revealed that UCP3 insufficiency accelerated left ventricular concentric remodeling, detrimental interstitial matrix remodeling, and fetal gene reprogramming during hypertension. Moreover, UCP3 insufficiency increased oxidative stress and led to greater impairment of protein kinase G signaling.

Conclusions

Our findings identified UCP3 insufficiency as a cause for increased incidence of left ventricular diastolic dysfunction during hypertension. The results add further support to the use of antioxidants targeting mitochondrial reactive oxygen species as an adjuvant therapy for preventing heart failure with preserved ejection fraction in individuals with obesity.

β-Hydroxybutyrate, a Ketone Body, Potentiates the Antioxidant Defense via Thioredoxin 1 Upregulation in Cardiomyocytes

Thioredoxin 1 (Trx1) is a major antioxidant that acts adaptively to protect the heart during the development of diabetic cardiomyopathy. The molecular mechanism(s) responsible for regulating the Trx1 level and/or activity during diabetic cardiomyopathy is unknown. β-hydroxybutyrate (βHB), a major ketone body in mammals, acts as an alternative energy source in cardiomyocytes under stress, but it also appears to be involved in additional mechanisms that protect the heart against stress. βHB upregulated Trx1 in primary cultured cardiomyocytes in a dose- and a time-dependent manner and a ketogenic diet upregulated Trx1 in the heart. βHB protected cardiomyocytes against H₂O₂-induced death, an effect that was abolished in the presence of Trx1 knockdown. βHB also alleviated the H₂O₂-induced inhibition of mTOR and AMPK, known targets of Trx1, in a Trx1-dependent manner, suggesting that βHB potentiates Trx1 function. It has been shown that βHB is a natural inhibitor of HDAC1 and knockdown of HDAC1 upregulated Trx1 in cardiomyocytes, suggesting that βHB may upregulate Trx1 through HDAC inhibition. βHB induced Trx1 acetylation and inhibited Trx1 degradation, suggesting that βHB-induced inhibition of HDAC1 may stabilize Trx1 through protein acetylation. These results suggest that βHB potentiates the antioxidant defense in cardiomyocytes through the inhibition of HDAC1 and the increased acetylation and consequent stabilization of Trx1. Thus, modest upregulation of ketone bodies in diabetic hearts may protect the heart through the upregulation of Trx1.

PEX5 prevents cardiomyocyte hypertrophy via suppressing the redox-sensitive signaling pathways MAPKs and STAT3

Peroxisomal biogenesis factor 5 (PEX5) is a member of peroxisome biogenesis protein family which serves as a shuttle receptor for the import of peroxisome matrix protein. The function of PEX5 on cardiomyocyte hypertrophy remained to be elucidated. Our study demonstrated that the protein expression level of PEX5 was declined in primary neonatal rat cardiomyocytes treated with phenylephrine (PE) and hearts from cardiac hypertrophic rats induced by abdominal aortic constriction (AAC). Overexpression of PEX5 alleviated cardiomyocyte hypertrophy induced by PE, while silencing of PEX5 exacerbated cardiomyocyte hypertrophy. PEX5 improved redox imbalance by decreasing cellular reactive oxygen species level and preserving peroxisomal catalase. Moreover, PEX5 knockdown aggravated PE-induced activation of redox-sensitive signaling pathways, including mitogen-activated protein kinase (MAPK) pathway and signal transducer and activator of transcription 3 (STAT3); whereas PEX5 overexpression suppressed activation of MAPK and STAT3. But PEX5 did not affect PE-induced phosphorylation of mammalian target of rapamycin (mTOR). In conclusion, the present study suggests that PEX5 protects cardiomyocyte against hypertrophy via regulating redox homeostasis and inhibiting redox-sensitive signaling pathways MAPK and STAT3.

Borneol in cardio-cerebrovascular diseases: Pharmacological actions, mechanisms, and therapeutics

With the coming acceleration of global population aging, the incidence rate of cardio-cerebrovascular diseases (CVDs) is increasing. It has become the leading cause of human mortality. As a natural drug, borneol (BO) not only has anti-inflammatory, anti-oxidant, anti-apoptotic, anti-coagulant activities and improves energy metabolism but can also promote drugs to enter the target organs or tissues through various physiological barriers, such as the blood-brain barrier (BBB), mucous membrane, skin. Thus, it has a significant therapeutic effect on various CVDs, which has been confirmed in a large number of studies. However, the pharmacological actions and mechanisms of BO on CVDs have not been fully investigated. Hence, this review summarizes the pharmacological actions and possible mechanisms of BO, which provides novel ideas for the treatment of CVDs.

Role of the ROS-JNK Signaling Pathway in Hypoxia-Induced Atrial Fibrotic Responses in HL-1 Cardiomyocytes

By promoting atrial structural remodeling, atrial hypoxia contributes to the development of the atrial fibrillation substrate. Our study aimed to investigate the modulatory effect of hypoxia on profibrotic activity in cultured HL-1 cardiomyocytes and explore the possible signaling transduction mechanisms of profibrotic activity in vitro. Hypoxia (1% O₂) significantly and time-dependently increased the expression of hypoxia-inducible factor (HIF)-1α and fibrotic marker proteins collagen I and III (COL1A and COL3A), transforming growth factor (TGF)-β1 and α-smooth muscle actin (SMA). Western blot or immunohistochemistry analysis showed that hypoxia-induced increase in COL1A and COL3A was significantly attenuated by the addition of SP600125 (a specific c-Jun N-terminal kinase [JNK] inhibitor) or expression of dominant-negative JNK before hypoxia treatment. The inhibition of hypoxia-activated phosphorylation of JNK signal components (JNK, MKK4, nuclear c-Jun and ATF-2) by pre-treatment with SP600125 could suppress hypoxia-stimulated HIF-1α upregulation and fibrotic marker proteins expression. Hypoxia significantly increased reactive oxygen species (ROS) production in cultured HL-1 atrial cells. Pre-treatment with N-acetylcysteine significantly abrogated the expression of nuclear HIF-1α, JNK transduction components and fibrotic marker proteins. Taken together, these findings indicated that the hypoxia-induced atrial profibrotic response occurs mainly via the ROS/JNK pathway, its downstream upregulation of HIF-1α and c-Jun/ATF2 phosphorylation and nuclear translocation to up-regulate the expression of fibrosis-related proteins (COL1A, COL3A, TGF-β1 and α-SMA). Our result suggests that suppression of ROS/JNK signaling pathway is a critical mechanism for developing a novel therapeutic strategy against atrial fibrillation.

Sunitinib-induced cardiac hypertrophy and the endothelin axis

Anti-angiogenics drugs in clinical use for cancer treatment induce cardiotoxic side effects. The endothelin axis is involved in hypertension and cardiac remodelling, and addition of an endothelin receptor antagonist to the anti-angiogenic sunitinib was shown to reduce cardiotoxicity of sunitinib in mice. Here, we explored further the antidote effect of the endothelin receptor antagonist macitentan in sunitinib-treated animals on cardiac remodeling.

Methods: Tumor-bearing mice treated per os daily by sunitinib or vehicle were imaged before and after 1, 3 and 6 weeks of treatment by positron emission tomography using [¹⁸F]fluorodeoxyglucose and by echocardiography. Non-tumor-bearing animals were randomly assigned to be treated per os daily by vehicle or sunitinib or macitentan or sunitinib+macitentan, and imaged by echocardiography after 5 weeks. Hearts were harvested for histology and molecular analysis at the end of in vivo exploration.

Results: Sunitinib treatment increases left ventricular mass and ejection fraction and induces cardiac fibrosis. Sunitinib also induces an early increase in cardiac uptake of [¹⁸F]fluorodeoxyglucose, which is significantly correlated with increased left ventricular mass at the end of treatment. Co-administration of macitentan prevents sunitinib-induced hypertension, increase in ejection fraction and cardiac fibrosis, but fails to prevent increase of the left ventricular mass.

Conclusion: Early metabolic changes predict sunitinib-induced cardiac remodeling. Endothelin blockade can prevent some but not all cardiotoxic side-effects of sunitinib, in particular left ventricle hypertrophy that appears to be induced by sunitinib through an endothelin-independent mechanism.

Betulinic Acid Protects DOX-Triggered Cardiomyocyte Hypertrophy Response through the GATA-4/Calcineurin/NFAT Pathway

Cardiac hypertrophy is a major risk factor for heart failure and leads to cardiovascular morbidity and mortality. Doxorubicin (DOX) is regarded as one of the most potent anthracycline antibiotic agents; however, its clinical usage has some limitations because it has serious cardiotoxic side effects such as dilated cardiomyopathy and congestive heart failure. Betulinic acid (BA) is a pentacyclic-cyclic lupane-type triterpene that has been reported to have anti-bacterial, anti-inflammatory, anti-vascular neogenesis, and anti-fibrotic effects. However, there is no study about its direct effect on DOX induced cardiac hypertrophy and apoptosis. The present study aims to investigate the effect of BA on DOX-induced cardiomyocyte hypertrophy and apoptosis in vitro in H9c2 cells. The H9c2 cells were stimulated with DOX (1 µM) in the presence or absence of BA (0.1-1 μM) and incubated for 24 h. The results of the present study indicated that DOX induces the increase cell surface area and the upregulation of hypertrophy markers including atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), beta-myosin heavy chain (β-MHC), and Myosin Light Chain-2 (MLC2) in H9c2 cells. However, the pathological hypertrophic responses were downregulated after BA treatment. Moreover, phosphorylation of JNK, ERK, and p38 in DOX treated H9c2 cells was blocked by BA. As a result of measuring the change in ROS generation using DCF-DA, BA significantly inhibited DOX-induced the production of intracellular reactive oxygen species (ROS) when BA was treated at a concentration of over 0.1 µM. DOX-induced activation of GATA-4 and calcineurin/NFAT-3 signaling pathway were remarkably improved by pre-treating of BA to H9c2 cells. In addition, BA treatment significantly reduced DOX-induced cell apoptosis and protein expression levels of Bax and cleaved caspase-3/-9, while the expression of Bcl-2 was increased by BA. Therefore, BA can be a potential treatment for cardiomyocyte hypertrophy and apoptosis that lead to sudden heart failure.

The Role of microRNAs in Heart Failure: A Systematic Review

MicroRNAs are highly investigated for their role in the pathogenesis of cardiovascular diseases. Nevertheless, evidence for clinical implementation is still lacking. In our systematic review, we evaluated the potential of microRNAs as pathophysiological and diagnostic biomarkers of heart failure. We identified 72 differentially expressed microRNA molecules among groups of heart failure patients and control groups by searching the PubMed database. We did not identify a substantial overlap of differentially expressed microRNAs among different studies; only five microRNAs (miR-1228, miR-122, miR-423-5p, miR-142-3p, and exosomal miR-92b-5p) were differentially expressed in more than one included study. Gene set enrichment analysis, based on the gene targets of microRNAs presented in the included studies, showed that gene targets of differentially expressed microRNAs were enriched in the MAPK, TGFβ, PI3K-Akt, and IL-2 signaling pathways, as well as apoptosis pathway, p53 activity regulation, and angiogenesis pathway. Results of our systematic review show that there is currently insufficient support for the use of any of the presented microRNAs as pathophysiological or prognostic biomarkers in the clinical setting.

Targeting cardiac fibrosis in heart failure with preserved ejection fraction: mirage or miracle?

Cardiac fibrosis is central to the pathology of heart failure, particularly heart failure with preserved ejection fraction (HFpEF). Irrespective of the underlying profibrotic condition (e.g. ageing, diabetes, hypertension), maladaptive cardiac fibrosis is defined by the transformation of resident fibroblasts to matrix-secreting myofibroblasts. Numerous profibrotic factors have been identified at the molecular level (e.g. TGFβ, IL11, AngII), which activate gene expression programs for myofibroblast activation. A number of existing HF therapies indirectly target fibrotic pathways; however, despite multiple clinical trials in HFpEF, a specific clinically effective antifibrotic therapy remains elusive. Therapeutic inhibition of TGFβ, the master-regulator of fibrosis, has unfortunately proven toxic and ineffective in clinical trials to date, and new approaches are needed. In this review, we discuss the pathophysiology and clinical implications of interstitial fibrosis in HFpEF. We provide an overview of trials targeting fibrosis in HFpEF to date and discuss the promise of potential new therapeutic approaches and targets in the context of underlying molecular mechanisms.

STEAP3 (Six-Transmembrane Epithelial Antigen of Prostate 3) Inhibits Pathological Cardiac Hypertrophy

Pathological cardiac hypertrophy is one of the major predictors and inducers of heart failure, the end stage of various cardiovascular diseases. However, the molecular mechanisms underlying pathogenesis of pathological cardiac hypertrophy remain largely unknown. Here, we provided the first evidence that STEAP3 (Six-Transmembrane Epithelial Antigen of Prostate 3) is a key negative regulator of this disease. We found that the expression of STEAP3 was reduced in pressure overload-induced hypertrophic hearts and phenylephrine-induced hypertrophic cardiomyocytes. In a transverse aortic constriction-triggered mouse cardiac hypertrophy model, STEAP3 deficiency remarkably deteriorated cardiac hypertrophy and fibrosis, whereas the opposite phenotype was observed in the cardiomyocyte-specific STEAP3 overexpressing mice. Accordingly, STEAP3 significantly mitigated phenylephrine-induced cell enlargement in primary neonatal rat cardiomyocytes. Mechanistically, via RNA-seq and immunoprecipitation-mass screening, we demonstrated that STEAP3 directly bond to Rho family small GTPase 1 and suppressed the activation of downstream mitogen-activated protein kinase-extracellular signal-regulated kinase signaling cascade. Remarkably, the antihypertrophic effect of STEAP3 was largely blocked by overexpression of constitutively active mutant Rac1 (G12V). Our study indicates that STEAP3 serves as a novel negative regulator of pathological cardiac hypertrophy by blocking the activation of the Rac1-dependent signaling cascade and may contribute to exploring effective therapeutic strategies of pathological cardiac hypertrophy treatment.

C1q-tumour necrosis factor-related protein-3 exacerbates cardiac hypertrophy in mice

AIMS

C1q-tumour necrosis factor-related protein-3 (CTRP3) is an adipokine and a paralog of adiponectin. Our previous study showed that CTRP3 attenuated diabetes-related cardiomyopathy. However, the precise role of CTRP3 in cardiac hypertrophy remains unclear. This study was aimed to clarify the role of CTRP3 involved in cardiac hypertrophy.

METHODS AND RESULTS

Cardiomyocyte-specific CTRP3 overexpression was achieved using an adeno-associated virus system, and cardiac CTRP3 expression was knocked down using gene delivery of specific short hairpin RNAs in vivo. CTRP3 expression was upregulated in murine hypertrophic hearts and failing human hearts. Increased CTRP3 was mainly derived from cardiomyocytes and induced by the production of reactive oxygen species (ROS) during the hypertrophic response. CTRP3-overexpressing mice exhibited exacerbated cardiac hypertrophy and cardiac dysfunction in response to pressure overload. Conversely, Ctrp3 deficiency in the heart resulted in an alleviated hypertrophic phenotype. CTRP3 induced hypertrophy in cardiomyocytes, which could be blocked by the addition of CTRP3 antibody in the media. Detection of signalling pathways showed that pressure overload-induced activation of the transforming growth factor β-activated kinase 1 (TAK1)-c-Jun N-terminal kinase (JNK) pathway was enhanced by CTRP3 overexpression and inhibited by CTRP3 disruption. Furthermore, we found that CTRP3 lost its pro-hypertrophic effects in cardiomyocyte-specific Tak1 knockout mice. Protein kinase A (PKA) was involved in the activation of TAK1 by CTRP3.

CONCLUSION

In conclusion, our results suggest that CTRP3 promotes pressure overload-induced cardiac hypertrophy via activation of the TAK1-JNK axis.

LncRNA SNHG1 regulates vascular endothelial cell proliferation and angiogenesis via miR-196a

Inflammatory cytokines are important protagonists in the formation of atherosclerotic plaques, triggering effects throughout the atherosclerotic vessels due to the destruction in proliferation, migration and angiogenesis of endothelial cells. In this study, we found SNHG1 is upregulated in TNF-α-treated HUVECs. We silenced SNHG1 and found it inhibited vascular endothelial cell proliferation and angiogenesis. In the other hand, exogenetic overexpression of SNHG1 promotes proliferation, migration and angiogenesis. Then we demonstrated that SNHG1 may interact directly with miR-196a to act as a miR-196a sponge. Further, MAPK6 were predicted to be the target of miR-196a. So we blocked miR-196a, which increased expression level of MAPK6, enhanced cell proliferation, migration and angiogenesis. These data indicated that SNHG1/miR-196a/MAPK6 axis may take a part in autophagy regulation in TNF-α-treated HUVECs. The subsequent rescue experiments come to the results ascertained the specificity of SNHG1/miR-196a/MAPK6 axis in regulating MAPK6. Overall, our findings demonstrate a novel mechanism by which SNHG1 overexpression protects the function of HUVECs, which may delay the progression of AS. SNHG1/miR-196a/MAPK6 axis may be of therapeutic significance in AS.

Delphinidin attenuates pathological cardiac hypertrophy via the AMPK/NOX/MAPK signaling pathway

Reactive oxygen species (ROS) play a pivotal role in the development of pathological cardiac hypertrophy. Delphinidin, a natural flavonoid, was reported to exert marked antioxidative effects. Therefore, we investigated whether delphinidin ameliorates pathological cardiac hypertrophy via inhibiting oxidative stress. In this study, male C57BL/6 mice were treated with DMSO or delphinidin after surgery. Neonatal rat cardiomyocytes (NRCMs) were treated with angiotensin II (Ang II) and delphinidin in vitro. Eighteen-month-old mice were administered delphinidin to investigate the effect of delphinidin on aging-related cardiac hypertrophy. Through analyses of hypertrophic cardiomyocyte growth, fibrosis and cardiac function, delphinidin was demonstrated to confer resistance to aging- and transverse aortic constriction (TAC)-induced cardiac hypertrophy in vivo and attenuate Ang II-induced cardiomyocyte hypertrophy in vitro by significantly suppressing hypertrophic growth and the deposition of fibrosis. Mechanistically, delphinidin reduced ROS accumulation upon Ang II stimulation through the direct activation of AMP-activated protein kinase (AMPK) and subsequent inhibition of the activity of Rac1 and expression of p47^phox. In addition, excessive levels of ERK1/2, P38 and JNK1/2 phosphorylation induced by oxidative stress were abrogated by delphinidin. Delphinidin was conclusively shown to repress pathological cardiac hypertrophy by modulating oxidative stress through the AMPK/NADPH oxidase (NOX)/mitogen-activated protein kinase (MAPK) signaling pathway.

Use of a Systematic Pharmacological Methodology to Explore the Mechanism of Shengmai Powder in Treating Diabetic Cardiomyopathy

BACKGROUND Cardiovascular complications, such as diabetic cardiomyopathy (DCM), are the leading cause of death in diabetic patients. Shengmai Powder (SMP) was found to have cardioprotective effects. MATERIAL AND METHODS Based on the systematic pharmacological methodology, this research determined the genes of DCM and the known targets of SMP, predicted potential compounds and targets of SMP, constructed networks for DCM and SMP, and performed network analysis. RESULTS Five network were constructed: (1) the DCM gene PPI network; (2) the Compound-compound target network of SMP; (3) the SMP-DCM PPI network; (4) the Compound-known target network of SMP; (5) and the SMP known target-DCM PPI network. Several DCM and treatment related targets, clusters, signaling pathways, and biological processes were found. CONCLUSIONS SMP is able to regulate glycometabolism-related, lipid metabolism-related, inflammatory response-related, oxidative stress-related signaling pathways, and biological processes and targets, which suggests that SMP may have a therapeutic effect on DCM.

Differences in microRNA-29 and Pro-fibrotic Gene Expression in Mouse and Human Hypertrophic Cardiomyopathy

Background: Hypertrophic cardiomyopathy (HCM) is characterized by myocyte hypertrophy and fibrosis. Studies in two mouse models (R92W-TnT/R403Q-MyHC) at early HCM stage revealed upregulation of endothelin (ET1) signaling in both mutants, but TGFβ signaling only in TnT mutants. Dysregulation of miR-29 expression has been implicated in cardiac fibrosis. But it is unknown whether expression of miR-29a/b/c and profibrotic genes is commonly regulated in mouse and human HCM.

Methods: In order to understand mechanisms underlying fibrosis in HCM, and examine similarities/differences in expression of miR-29a/b/c and several profibrotic genes in mouse and human HCM, we performed parallel studies in rat cardiac myocyte/fibroblast cultures, examined gene expression in two mouse models of (non-obstructive) HCM (R92W-TnT, R403Q-MyHC)/controls at early (5 weeks) and established (24 weeks) disease stage, and analyzed publicly available mRNA/miRNA expression data from obstructive-HCM patients undergoing septal myectomy/controls (unused donor hearts).

Results: Myocyte cultures: ET1 increased superoxide/H₂O₂, stimulated TGFβ expression/secretion, and suppressed miR-29a expression in myocytes. The effect of ET1 on miR-29 and TGFβ expression/secretion was antagonized by N-acetyl-cysteine, a reactive oxygen species scavenger. Fibroblast cultures: ET1 had no effect on pro-fibrotic gene expression in fibroblasts. TGFβ1/TGFβ2 suppressed miR-29a and increased collagen expression, which was abolished by miR-29a overexpression. Mouse and human HCM: Expression of miR-29a/b/c was lower, and TGFB1/collagen gene expression was higher in TnT mutant-LV at 5 and 24 weeks; no difference was observed in expression of these genes in MyHC mutant-LV and in human myectomy tissue. TGFB2 expression was higher in LV of both mutant mice and human myectomy tissue. ACE2, a negative regulator of the renin-angiotensin-aldosterone system, was the most upregulated transcript in human myectomy tissue. Pathway analysis predicted upregulation of the anti-hypertrophic/anti-fibrotic liver X receptor/retinoid X receptor (LXR/RXR) pathway only in human myectomy tissue.

Conclusions: Our in vitro studies suggest that activation of ET1 signaling in cardiac myocytes increases reactive oxygen species and stimulates TGFβ secretion, which downregulates miR-29a and increases collagen in fibroblasts, thus contributing to fibrosis. Our gene expression studies in mouse and human HCM reveal allele-specific differences in miR-29 family/profibrotic gene expression in mouse HCM, and activation of anti-hypertrophic/anti-fibrotic genes and pathways in human HCM.

The cytoprotective impact of yes-associated protein 1 after ischemia-reperfusion injury in AC16 human cardiomyocytes

The Hippo-signaling pathway is a mechanism implicated in cardiomyocyte cytoprotection and regeneration after a myocardial infarction. Yes-associated protein 1, the main effector protein of this pathway, acts as a co-transcriptional activator to promote cardiomyocyte proliferation and survival. However, the biological mechanisms by which yes-associated protein 1 protects the heart post-MI are currently unknown. Here, we propose that yes-associated protein 1 plays a critical role in cardiomyocyte cytoprotection after simulated ischemia-reperfusion injury. AC16 human cardiomyocytes were infected with lentiviral plasmids containing normal human yes-associated protein 1 and a constitutively active form of YAP, YAP1S127A. Cells were exposed to ischemia-reperfusion injury using a hypoxic chamber. Hippo-signaling characterization after ischemia-reperfusion injury was performed via Western blotting and reverse transcriptase polymerase chain reaction. Cell viability, apoptosis, and cellular hypertrophy were assessed as a measure of cytoprotection. The GSK3β inhibitor CHIR99021 was used to investigate cross-talk between Hippo and Wnt-signaling and their role in cytoprotection after ischemia-reperfusion-injury. Ischemia-reperfusion injury resulted in significant decreased expression of the non-phosphorylated Hippo signaling kinases MST1 and LATS1, along with decreased expression of YAP/TAZ. Overexpression of yes-associated protein 1 improved cellular viability, while reducing hypertrophy and apoptosis via the ATM/ATR DNA damage response pathway. Activation of β-catenin in YAP-infected cardiomyocytes synergistically reduced cellular hypertrophy after ischemia-reperfusion-injury. Our findings indicate that yes-associated protein 1 is cytoprotective in AC16 human cardiomyocytes after ischemia-reperfusion injury, which may be mediated by co-activation of the canonical Wnt/β-catenin pathway. Thus, activation of yes-associated protein 1 may be a novel therapeutic to repair the infarcted myocardium.

Impact statement

Genetically engineering the cells of the heart after myocardial infarction to display a more regenerative phenotype is a promising therapy for heart failure patients. Here, we support a regenerative role for yes-associated protein 1, the main effector protein of the Hippo signaling pathway, in AC16 human cardiomyocytes as a potential therapeutic gene target for cardiac repair after myocardial infarction.

The Effects of Bradykinin B1 Receptor Antagonism on the Myocardial and Vascular Consequences of Hypertension in SHR Rats

It is known that non-steroidal anti-inflammatory drugs increase cardiovascular (CV) morbidity and mortality. In this study, we examined whether a novel anti-inflammatory drug, bradykinin B1 receptor antagonist (FGY-1153) treatment could influence the development of hypertensive organ damages in spontaneously hypertensive rats (SHR). SHRs were treated with low (FGY-120) or high dose FGY-1153 (FGY-400) and with placebo (Control) for 26 weeks. Wistar–Kyoto rats were used as aged-matched, normotensive controls (WKY). Body weight, food consumption and blood pressure were measured regularly. Echocardiography was performed at the beginning and at the end of the study. Light and electron microscopic analysis of heart and great vessels were performed, and the extent of fibrotic areas was measured. The phosphorylation state of prosurvival Akt-1/glycogen synthase kinase (GSK)-3β pathway and the activation of signaling factors playing part in the fibrotic processes – mitogen activated protein kinases (MAPKs), and TGF-β/Smad2 – were monitored using Western-blot. Body weight and food consumption as well as the elevated blood pressure in SHRs was not influenced by FGY-1153 treatment. However, both doses of FGY-1153 treatment decreased left ventricular (LV) hypertrophy and diastolic dysfunction in hypertensive animals. Moreover systolic LV function was also preserved in FGY-120 group. Increased intima-media thickness and interstitial fibrosis were not significantly diminished in great vessels. FGY-1153 treatment inhibited the expression of TGFβ and the phosphorylation of SMAD2 in the heart. Our results suggest that the tested novel anti-inflammatory compound has no deleterious effect on CV system, moreover it exerts moderate protective effect against the development of hypertensive cardiopathy.

Hydroxysafflor yellow A protects against angiotensin II‑induced hypertrophy

Myocardial infarction (MI) is life-threatening and is generally accompanied by myocardial hypertrophy. Notably, Hydroxysafflor yellow A (HSYA) can prevent tissue injuries. The objective of this study was to investigate the effect of HSYA on hypertrophy after MI. Hematoxylin and eosin (H&E) staining assays were performed to measure cell area. The protein synthesis rate was assessed using the ³H Leucine incorporation assay. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blot analysis and the immunohistochemical assay were used to detect the expression of target genes. The activity of superoxide dismutase (SOD), malondialdehyde (MDA) and the reactive oxygen species (ROS) generation were examined using commercial kits. Decreased myocardial hypertrophy was observed in animals treated with HSYA. Furthermore, the expression of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) was higher in HSYA administration groups compared with that in the MI model group. In H9c2 cardiomyocytes, the pretreatment with HSYA increased the cell viability, however, it reduced protein synthesis rate, mitigated cell surface area and decreased the expression of Brain natriuretic factor (BNP) and β-myosin heavy chain (β-MHC). By contrast, the downregulation of Nrf2 deteriorated and reversed the effect of Ang II and HSYA. Furthermore, oxidative stress was alleviated by HSYA via inhibiting ROS generation, modulating the activities of SOD and MDA. In addition, the expression of NAD(P)H:quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1) were recovered by the pretreatment of HSYA that was combated by siNrf2. In conclusion, HSYA exerted anti-hypertrophic effects, which was pertinent with the activation of Nrf2/NQO-1/HO-1 signaling pathway. The findings of this study may inspire a novel strategy to combat MI.

Secretoneurin suppresses cardiac hypertrophy through suppression of oxidant stress

The neuropeptide secretoneurin (SN) plays protective roles in myocardial ischemia. In the present study, the effect of SN in cardiac hypertrophy was investigated. We observed that, in isoproterenol (ISO) treatment induced cardiac or cardiomyocytes hypertrophy, a marked increase in the expression of endogenous SN in mouse plasma, myocardium and primary-cultured cardiomyocytes occurs. In hypertrophic mice, the heart size, heart weight/body weight (HW/BW) ratio, cardiomyocyte size, and atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) expression were significantly higher than those in controls but were effectively suppressed by SN gene therapy. Similarly, the protective effects of SN were also observed in cultured cardiomyocytes following ISO treatment. SN significantly increased the activity of catalase and superoxide dismutase (SOD) in parallel with the decrease in reactive oxygen species levels in cardiomyocytes. We observed that SN evoked the activation of all of the AMPK, P38/MAPK and ERK/MAPK pathways in cardiomyocytes, but pretreatment with only AMPK inhibitor (compound C) and ERK1/2/MAPK inhibitor (PD98059) counteracted the protective effects of SN against cardiomyocyte hypertrophy and the suppressive effects of SN on oxidant stress in cardiomyocytes. These results indicated that endogenous SN is induced in hypertrophic cardiomyocytes, and may play a protective role in the pathogenesis of cardiac hypertrophy. These results suggest that exogenous SN supplementation protects the cardiac hypertrophy induced by ISO treatment through the activation of AMPK and ERK/MAPK pathways, thus upregulating antioxidants and suppressing oxidative stress.

Pin1 facilitates isoproterenol‑induced cardiac fibrosis and collagen deposition by promoting oxidative stress and activating the MEK1/2‑ERK1/2 signal transduction pathway in rats

Peptidyl-prolyl cis/trans isomerase, NIMA-interacting 1 (Pin1) is a member of a large superfamily of phosphorylation-dependent peptidyl-prolyl cis/trans isomerases, which not only regulates multiple targets at various stages of cellular processes, but is also involved in the pathogenesis of several diseases, including microbial infection, cancer, asthma and Alzheimer's disease. However, the role of Pin1 in cardiac fibrosis remains to be fully elucidated. The present study investigated the potential mechanism of Pin1 in isoprenaline (ISO)-induced myocardial fibrosis in rats. The rats were randomly divided into three groups. Echocardiography was used to evaluate changes in the size, shape and function of the heart, and histological staining was performed to visualize inflammatory cell infiltration and fibrosis. Reverse transcription-quantitative polymerase chain reaction analysis, immunohistochemistry and Picrosirius red staining were used to differentiate collagen subtypes. Additionally, cardiac-specific phosphorylation of mitogen-activated protein kinase kinase 1/2 (MEK1/2) and extracellular-signal regulated protein kinase 1/2 (ERK1/2), and the activities of Pin1 and α-smooth muscle actin (α-SMA) and other oxidative stress parameters were estimated in the heart. The administration of ISO resulted in an increase in cardiac parameters and elevated the heart-to-body weight ratio. Histopathological examination of heart tissues revealed interstitial inflammatory cellular infiltrate and disorganized collagen fiber deposition. In addition, lipid peroxidation products and oxidative stress marker activity in plasma and tissues were significantly increased in the ISO-treated rats. Western blot analysis showed significantly elevated protein levels of phosphorylated Pin1, MEK1/2, ERK1/2 and α-SMA in remodeling hearts. Treatment with juglone following intraperitoneal injection of ISO significantly prevented inflammatory cell infiltration, improved cardiac function, and suppressed oxidative stresses and fibrotic alterations. In conclusion, the results of the present study suggested that the activation of Pin1 promoted cardiac extracellular matrix deposition and oxidative stress damage by regulating the phosphorylation of the MEK1/2-ERK1/2 signaling pathway and the expression of α-SMA. By contrast, the inhibition of Pin1 alleviated cardiac damage and fibrosis in the experimental models, suggesting that Pin1 contributed to the development of cardiac remodeling in ISO-administered rats, and that the inactivation of Pin1 may be a novel therapeutic candidate for the treatment of cardiovascular disease and heart failure.

2-aminoethoxydiphenyl borate provides an anti-oxidative effect and mediates cardioprotection during ischemia reperfusion in mice

Excessive levels of reactive oxygen species (ROS) and impaired Ca2+ homeostasis play central roles in the development of multiple cardiac pathologies, including cell death during ischemia-reperfusion (I/R) injury. In several organs, treatment with 2-aminoethoxydiphenyl borate (2-APB) was shown to have protective effects, generally believed to be due to Ca2+ channel inhibition. However, the mechanism of 2-APB-induced cardioprotection has not been fully investigated. Herein we investigated the protective effects of 2-APB treatment against cardiac pathogenesis and deciphered the underlying mechanisms. In neonatal rat cardiomyocytes, treatment with 2-APB was shown to prevent hydrogen peroxide (H2O2) -induced cell death by inhibiting the increase in intracellular Ca2+ levels. However, no 2-APB-sensitive channel blocker inhibited H2O2-induced cell death and a direct reaction between 2-APB and H2O2 was detected by 1H-NMR, suggesting that 2-APB chemically scavenges extracellular ROS and provides cytoprotection. In a mouse I/R model, treatment with 2-APB led to a considerable reduction in the infarct size after I/R, which was accompanied by the reduction in ROS levels and neutrophil infiltration, indicating that the anti-oxidative properties of 2-APB plays an important role in the prevention of I/R injury in vivo as well. Taken together, present results indicate that 2-APB treatment induces cardioprotection and prevents ROS-induced cardiomyocyte death, at least partially, by the direct scavenging of extracellular ROS. Therefore, administration of 2-APB may represent a promising therapeutic strategy for the treatment of ROS-related cardiac pathology including I/R injury.

Roles and Mechanisms of Herbal Medicine for Diabetic Cardiomyopathy: Current Status and Perspective

Diabetic cardiomyopathy is one of the major complications among patients with diabetes mellitus. Diabetic cardiomyopathy (DCM) is featured by left ventricular hypertrophy, myocardial fibrosis, and damaged left ventricular systolic and diastolic functions. The pathophysiological mechanisms include metabolic-altered substrate metabolism, dysfunction of microvascular, renin-angiotensin-aldosterone system (RAAS) activation, oxidative stress, cardiomyocyte apoptosis, mitochondrial dysfunction, and impaired Ca²⁺ handling. An array of molecules and signaling pathways such as p38 mitogen-activated protein kinase (p38 MAPK), c-Jun N-terminal kinase (JNK), and extracellular-regulated protein kinases (ERK) take roles in the pathogenesis of DCM. Currently, there was no remarkable effect in the treatment of DCM with application of single Western medicine. The myocardial protection actions of herbs have been gearing much attention. We present a review of the progress research of herbal medicine as a potential therapy for diabetic cardiomyopathy and the underlying mechanisms.

Redox modification of caveolar proteins in the cardiovascular system- role in cellular signalling and disease

Rapid and coordinated release of a variety of reactive oxygen species (ROS) such as superoxide (O₂^.-), hydrogen peroxide (H₂O₂) and peroxynitrite, in specific microdomains, play a crucial role in cell signalling in the cardiovascular system. These reactions are mediated by reversible and functional modifications of a wide variety of key proteins. Dysregulation of this oxidative signalling occurs in almost all forms of cardiovascular disease (CVD), including at the very early phases. Despite the heavily publicized failure of "antioxidants" to improve CVD progression, pharmacotherapies such as those targeting the renin-angiotensin system, or statins, exert at least part of their large clinical benefit via modulating cellular redox signalling. Over 250 proteins, including receptors, ion channels and pumps, and signalling proteins are found in the caveolae. An increasing proportion of these are being recognized as redox regulated-proteins, that reside in the immediate vicinity of the two major cellular sources of ROS, nicotinamide adenine dinucleotide phosphate oxidase (Nox) and uncoupled endothelial nitric oxide synthase (eNOS). This review focuses on what is known about redox signalling within the caveolae, as well as endogenous protective mechanisms utilized by the cell, and new approaches to targeting dysregulated redox signalling in the caveolae as a therapeutic strategy in CVD.

Physiological role of reactive oxygen species as promoters of natural defenses

It has been 60 yr since the discovery of reactive oxygen species (ROS) in biology and the beginning of the scientific community's attempt to understand the impact of the unpaired electron of ROS molecules in biological pathways, which was eventually noted to be toxic. Several studies have shown that the presence of ROS is essential in triggering or acting as a secondary factor for numerous pathologies, including metabolic and genetic diseases; however, it was demonstrated that chronic treatment with antioxidants failed to show efficacy and positive effects in the prevention of diseases or health complications that result from oxidative stress. On the contrary, such treatment has been shown to sometimes even worsen the disease. Because of the permanent presence of ROS in organisms, elaborate mechanisms to adapt with these reactive molecules and to use them without necessarily blocking or preventing their actions have been studied. There is now a large body of evidence that shows that living organisms have conformed to the presence of ROS and, in retrospect, have adapted to the bioactive molecules that are generated by ROS on proteins, lipids, and DNA. In addition, ROS have undergone a shift from being molecules that invoked oxidative damage in regulating signaling pathways that impinged on normal physiological and redox responses. Working in this direction, this review unlocks a new conception about the involvement of cellular oxidants in the maintenance of redox homeostasis in redox regulation of normal physiological functions, and an explanation for its essential role in numerous pathophysiological states is noted.-Roy, J., Galano, J.-M., Durand, T., Le Guennec, J.-Y., Lee, J. C.-Y. Physiological role of reactive oxygen species as promoters of natural defenses.

Stachydrine ameliorates isoproterenol-induced cardiac hypertrophy and fibrosis by suppressing inflammation and oxidative stress through inhibiting NF-κB and JAK/STAT signaling pathways in rats

Cardiac hypertrophy (CH), as one of the major causes of morbidity and mortality in the world, has become an independent and predictive risk factor for adverse cardiovascular events. However, progress in treatment remains sluggish in recent years. Therefore, compounds derived from non-toxic nature plants are urgently needed. Stachydrine (STA), which is isolated from Leonurus, has various activities, including resistance to cardiovascular disease, but little is known about its effect on CH or the mechanisms. We herein investigated the effect of STA on isoproterenol-induced CH and the underlying mechanisms. Treatment with STA significantly increased the ratios of heart weight/body weight, left ventricle weight/body weight and the cross-sectional areas of cardiomyocytes. In addition, STA significantly decreased the mRNA levels of atrial natriuretic peptide, B-type natriuretic peptide and β-myosin heavy chain. Furthermore, isoproterenol-induced fibrosis in rats receiving STA was significant attenuated, as evidenced by decreased ratio of fibrotic area/total area and decreased mRNA levels of collagens I and III. Given down-regulation of interleukin-6, tumor necrosis factor-α, interferon-γ (IFN-γ) and IFN-1β, treatment with STA significantly reversed the expressions of pro-inflammatory induced by isoproterenol. Moreover, STA attenuated the oxidative stress level in serum of isoproterenol-induced CH rats, as shown by increased activity of superoxide dismutase and decreased malondialdehyde level. STA inhibited the expressions of phosphorylated IκBα, NF-κB p65, JAK2 and STAT3 in vivo. Thus, both NF-κB and JAK/STAT signalings played essential roles in mediating the anti-CH effect of STA. Collectively, STA has a potent protective effect on isoproterenol-induced CH, with therapeutic implication for CH.

The Pathophysiological Role of NOX2 in Hypertension and Organ Damage

NADPH oxidases (NOXs) represent one of the major sources of reactive oxygen species in the vascular district. Reactive oxygen species are responsible for vascular damage that leads to several cardiovascular pathological conditions. Among NOX isoforms, NOX2 is widely expressed in many cells types, such as cardiomyocytes, endothelial cells, and vascular smooth muscle cells, confirming its pivotal role in vascular pathophysiology. Studies in mice models with systemic deletion of NOX2, as well as in transgenic mice overexpressing NOX2, have demonstrated the undeniable involvement of NOX2 in the development of hypertension, atherosclerosis, diabetes mellitus, cardiac hypertrophy, platelet aggregation, and aging. Of note, the inhibition of NOX2 has been found to be protective for cardiovascular homeostasis. Here, we review the evidence demonstrating that the modulation of NOX2 activity is able to improve vascular physiology, suggesting that NOX2 may be a potential target for therapeutic applications.

The ET-1-mediated carbonylation and degradation of ANXA1 induce inflammatory phenotype and proliferation of pulmonary artery smooth muscle cells in HPS

Hepatopulmonary syndrome (HPS) is a serious complication of advanced liver disease, which markedly increases mortality. Pulmonary vascular remodelling (PVR) induced by circulating mediators plays an important role in the pathogenesis of HPS, while the underlying mechanism remains undefined. In the present study, we reported that endothelin-1 (ET-1) is up-regulated and annexin A1(ANXA1) is down-regulated in HPS rat, and ET-1 decreases the ANXA1 expression in a dose-dependent manner in rat pulmonary arterial smooth muscle cells (PASMCs). Then, we showed that ANXA1 can decrease nuclear p-ERK1/2 accumulation and decrease the cyclin D1 expression, thus resulting in the subsequent inhibition of PASMCs proliferation. As previously reported, we confirmed that ET-1 decreases the ANXA1 protein levels by the carbonylation and degradation of ANXA1. In conclusion, our research links the signaling cascade of ET1-ANXA1-cell proliferation to a potential therapeutic strategy for blocking IPS-associated PVR.

Inhibition of Cardiac Hypertrophy Effects in D-Galactose-Induced Senescent Hearts by Alpinate Oxyphyllae Fructus Treatment

Aging is a complex physiological phenomenon accelerated by ROS accumulation, with multisystem decline and increasing vulnerability to degenerative diseases and death. Cardiac hypertrophy is a key pathophysiological component that accompanies the aging process. Alpinate Oxyphyllae Fructus (Alpinia oxyphylla MIQ, AOF) is a traditional Chinese medicine, which provides cardioprotective activity against aging, hypertension, and cerebrovascular disorders. In this study, we found the protective effect of AOF against cardiac hypertrophy in D-galactose-induced aging rat model. The results showed that treating rats with D-galactose resulted in pathological hypertrophy as evident from the morphology change, increased left ventricular weight/whole heart weight, and expression of hypertrophy-related markers (MYH7 and BNP). Both concentric and eccentric cardiac hypertrophy signaling proteins were upregulated in aging rat model. However, these pathological changes were significantly improved in AOF treated group (AM and AH) in a dose-dependent manner. AOF negatively modulated D-galactose-induced cardiac hypertrophy signaling mechanism to attenuate ventricular hypertrophy. These enhanced cardioprotective activities following oral administration of AOF reflect the potential use of AOF for antiaging treatments.

Sulfiredoxin involved in the protection of peroxiredoxins against hyperoxidation in the early hyperglycaemia

As a direct consequence of hyperglycaemia, the excessive generation of ROS is central to the pathogenesis of diabetic cardiomyopathy. We hypothesize that stimulation of high glucose (HG) results in an increased sulfiredoxin (Srx) expression, which regulates ROS signaling through reducing the hyperoxidized peroxiredoxins (Prxs). We show that hyperoxidized Prxs were initially reduced in the preliminary stage but then dramatically increased in advanced stage and these changes corresponded to a significant increase of Srx expression in the heart of diabetic rats. These time-dependent changes were also confirmed in neonatal cardiomyocytes and H9c2 cells treated with HG. Moreover, the reduction rate of hyperoxidized Prxs was greatly improved in the HG 24h group, which had an elevated expression of Srx. Our data also show that HG-induced AP1 activation and Srx expression were almost abolished by JNK inhibitor and N-acetylcysteine (NAC). In addition, siRNA-Srx suppressed HG-induced ANP and β-MHC gene expression. These observations suggest that activation of AP1 induced by HG is important for the expression of Srx and the reduction of hyperoxidized Prxs in cardiomyocytes. This Srx induction maybe is the pivotal compensatory protection mechanism against oxidative stress in diabetes or hyperglycaemia. Most interestingly, hyperoxidized Prxs/Srx pathway may be involved in the cardiac hypertrophy signaling of diabetes.

Melatonin attenuates postmyocardial infarction injury via increasing Tom70 expression

Mitochondrial dysfunction leads to reactive oxygen species (ROS) overload, exacerbating injury in myocardial infarction (MI). As a receptor for translocases in the outer mitochondrial membrane (Tom) complex, Tom70 has an unknown function in MI, including melatonin-induced protection against MI injury. We delivered specific small interfering RNAs against Tom70 or lentivirus vectors carrying Tom70a sequences into the left ventricles of mice or to cultured neonatal murine ventricular myocytes (NMVMs). At 48 h post-transfection, the left anterior descending coronary arteries of mice were permanently ligated, while the NMVMs underwent continuous hypoxia. At 24 h after ischemia/hypoxia, oxidative stress was assessed by dihydroethidium and lucigenin-enhanced luminescence, mitochondrial damage by transmission electron microscopy and ATP content, and cell apoptosis by terminal deoxynucleotidyl transferase dUTP nick-end labeling and caspase-3 assay. At 4 weeks after ischemia, cardiac function and fibrosis were evaluated in mice by echocardiography and Masson's trichrome staining, respectively. Ischemic/hypoxic insult reduced Tom70 expression in cardiomyocytes. Tom70 downregulation aggravated post-MI injury, with increased mitochondrial fragmentation and ROS overload. In contrast, Tom70 upregulation alleviated post-MI injury, with improved mitochondrial integrity and decreased ROS production. PGC-1α/Tom70 expression in ischemic myocardium was increased with melatonin alone, but not when combined with luzindole. Melatonin attenuated post-MI injury in control but not in Tom70-deficient mice. N-acetylcysteine (NAC) reversed the adverse effects of Tom70 deficiency in mitochondria and cardiomyocytes, but at a much higher concentration than melatonin. Our findings showed that Tom70 is essential for melatonin-induced protection against post-MI injury, by breaking the cycle of mitochondrial impairment and ROS generation.

Mitochondria in Structural and Functional Cardiac Remodeling

The heart must function continuously as it is responsible for both supplying oxygen and nutrients throughout the entire body, as well as for the transport of waste products to excretory organs. When facing either a physiological or pathological increase in cardiac demand, the heart undergoes structural and functional remodeling as a means of adapting to increased workload. These adaptive responses can include changes in gene expression, protein composition, and structure of sub-cellular organelles involved in energy production and metabolism. Mitochondria are essential for cardiac function, as they supply the ATP necessary to support continuous cycles of contraction and relaxation. In addition, mitochondria carry out other important processes, including synthesis of essential cellular components, calcium buffering, and initiation of cell death signals. Not surprisingly, mitochondrial dysfunction has been linked to several cardiovascular disorders, including hypertension, cardiac hypertrophy, ischemia/reperfusion and heart failure. The present chapter will discuss how changes in mitochondrial cristae structure, fusion/fission dynamics, fatty acid oxidation, ATP production, and the generation of reactive oxygen species might impact cardiac structure and function, particularly in the context of pathological hypertrophy and fibrotic response. In addition, the mechanistic role of mitochondria in autophagy and programmed cell death of cardiomyocytes will be addressed. Here we will also review strategies to improve mitochondrial function and discuss their cardioprotective potential.

The Role of ERK1/2 in the Development of Diabetic Cardiomyopathy

Diabetes mellitus is a chronic metabolic condition that affects carbohydrate, lipid and protein metabolism and may impair numerous organs and functions of the organism. Cardiac dysfunction afflicts many patients who experience the oxidative stress of the heart. Diabetic cardiomyopathy (DCM) is one of the major complications that accounts for more than half of diabetes-related morbidity and mortality cases. Chronic hyperglycemia and hyperlipidemia from diabetes mellitus cause cardiac oxidative stress, endothelial dysfunction, impaired cellular calcium handling, mitochondrial dysfunction, metabolic disturbances, and remodeling of the extracellular matrix, which ultimately lead to DCM. Although many studies have explored the mechanisms leading to DCM, the pathophysiology of DCM has not yet been fully clarified. In fact, as a potential mechanism, the associations between DCM development and mitogen-activated protein kinase (MAPK) activation have been the subjects of tremendous interest. Nonetheless, much remains to be investigated, such as tissue- and cell-specific processes of selection of MAPK activation between pro-apoptotic vs. pro-survival fate, as well as their relation with the pathogenesis of diabetes and associated complications. In general, it turns out that MAPK signaling pathways, such as extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal protein kinase (JNK) and p38 MAP kinase, are demonstrated to be actively involved in myocardial dysfunction, hypertrophy, fibrosis and heart failure. As one of MAPK family members, the activation of ERK1/2 has also been known to be involved in cardiac hypertrophy and dysfunction. However, many recent studies have demonstrated that ERK1/2 signaling activation also plays a crucial role in FGF21 signaling and exerts a protective environment of glucose and lipid metabolism, therefore preventing abnormal healing and cardiac dysfunction. The duration, extent, and subcellular compartment of ERK1/2 activation are vital to differential biological effects of ERK1/2. Moreover, many intracellular events, including mitochondrial signaling and protein kinases, manipulate signaling upstream and downstream of MAPK, to influence myocardial survival or death. In this review, we will summarize the roles of ERK1/2 pathways in DCM development by the evidence from current studies and will present novel opinions on "differential influence of ERK1/2 action in cardiac dysfunction, and protection against myocardial ischemia-reperfusion injury".

Cardiac Hypertrophy: An Introduction to Molecular and Cellular Basis

Ventricular hypertrophy is an ominous escalation of hemodynamically stressful conditions such as hypertension and valve disease. The pathophysiology of hypertrophy is complex and multifactorial, as it touches on several cellular and molecular systems. Understanding the molecular background of cardiac hypertrophy is essential in order to protect the myocardium from pathological remodeling, or slow down the destined progression to heart failure. In this review we highlight the most important molecular aspects of cardiac hypertrophic growth in light of the currently available published research data.

Diosmetin prevents TGF-β1-induced epithelial-mesenchymal transition via ROS/MAPK signaling pathways

AIMS

Epithelial-mesenchymal transition (EMT) plays a critical role in airway repair and remodeling in many respiratory diseases such as asthma and pulmonary fibrosis. The flavone aglycone, diosmetin, possesses anti-remodeling activity in a murine model of chronic asthma, but little is known about its effects on EMT. Herein, we investigated whether diosmetin inhibits transforming growth factor-β1 (TGF-β1)-induced EMT with underlying mechanisms in human bronchial epithelial (HBE) cells.

MAIN METHODS

HBE cells were incubated with TGF-β1 (10ng/ml), either alone or in combination with diosmetin for indicated times. We measured reactive oxygen species (ROS) levels using FACScan and immunofluorescent assays. We assessed protein expression of NADPH oxidase 4 (NOX4), superoxide dismutase (SOD), catalase, Akt, Erk, p38, and phosphorylation levels of Akt, Erk and p38 by Western blot analysis.

KEY FINDINGS

TGF-β1 promoted EMT and ROS generation in HBE cells. Diosmetin significantly suppressed TGF-β1-induced increases in cell migration and altered N-cadherin, E-cadherin, and α-smooth muscle actin expression. In addition, diosmetin prevented TGF-β1-induced intracellular ROS generation, down-regulated NOX4, and up-regulated SOD and catalase expression. Furthermore, diosmetin remarkably inhibited TGF-β1-induced phosphorylation of phosphoinositide 3-kinase (PI3K)/Akt and mitogen activated protein kinase (MAPK) pathways in HBE cells.

SIGNIFICANCE

Our results demonstrate for the first time that diosmetin alleviates TGF-β1-induced EMT by inhibiting ROS generation and inactivating PI3K/Akt and MAPK pathways. Our findings revealed a new role for diosmetin in reducing airway remodeling and fibrogenesis.

Dual-specificity phosphatase 14 protects the heart from aortic banding-induced cardiac hypertrophy and dysfunction through inactivation of TAK1-P38MAPK/-JNK1/2 signaling pathway

Dual-specificity phosphatase 14 (Dusp14), an important negative modulator of mitogen-activated protein kinase (MAPK) signaling pathways, has been implicated in inflammatory immune response, cancers, cell differentiation and proliferation. The role of Dusp14 in chronic pressure overload-induced cardiac hypertrophy has not been explored. Here we have shown that Dusp14-/- knockout mice and cardiac-specific Dusp14 transgenic mice were generated and subjected to aortic banding (AB) for 4 weeks. Our results demonstrated that genetic loss of Dusp14 significantly aggravated cardiac hypertrophy, fibrosis, ventricular dilation and dysfunction, whereas transgenic cardiac-specific Dusp14 overexpression significantly attenuated AB-induced cardiac dysfunction and remodeling. In vitro, adenoviral overexpression of constitutive Dusp14 blocked angiotensin II-induced hypertrophic growth of cardiomyocytes, while Dusp14 knockdown led to opposite effects. Mechanistically, excessive phosphorylation of TAK1, P38MAPK and JNK1/2 was evidenced in Dusp14-/- knockout mice post-AB and inactivation of TAK1-P38MAPK and -JNK1/2 signaling using TAK1 inhibitor 5Z-7-ox shares similar antihypertrophic effect as Dusp14 overexpression. Moreover, we show that Dusp14 directly interacted with TAK1. Results from present experiments indicate that Dusp14 protects the heart from AB-induced cardiac hypertrophy and dysfunction possibly through inactivation of TAK1-P38MAPK/-JNK1/2 signaling pathway. Future studies are warranted to test the feasibility of overexpressing Dusp14 as a therapeutic strategy to attenuate cardiac hypertrophy and failure.

Novel Perspectives in Redox Biology and Pathophysiology of Failing Myocytes: Modulation of the Intramyocardial Redox Milieu for Therapeutic Interventions-A Review Article from the Working Group of Cardiac Cell Biology, Italian Society of Cardiology

The prevalence of heart failure (HF) is still increasing worldwide, with enormous human, social, and economic costs, in spite of huge efforts in understanding pathogenetic mechanisms and in developing effective therapies that have transformed this syndrome into a chronic disease. Myocardial redox imbalance is a hallmark of this syndrome, since excessive reactive oxygen and nitrogen species can behave as signaling molecules in the pathogenesis of hypertrophy and heart failure, leading to dysregulation of cellular calcium handling, of the contractile machinery, of myocardial energetics and metabolism, and of extracellular matrix deposition. Recently, following new interesting advances in understanding myocardial ROS and RNS signaling pathways, new promising therapeutical approaches with antioxidant properties are being developed, keeping in mind that scavenging ROS and RNS tout court is detrimental as well, since these molecules also play a role in physiological myocardial homeostasis.

Rapid effects of aldosterone in primary cultures of cardiomyocytes - do they suggest the existence of a membrane-bound receptor?

Aldosterone acts on its target tissue through a classical mechanism or through the rapid pathway through a putative membrane-bound receptor. Our goal here was to better understand the molecular and biochemical rapid mechanisms responsible for aldosterone-induced cardiomyocyte hypertrophy. We have evaluated the hypertrophic process through the levels of ANP, which was confirmed by the analysis of the superficial area of cardiomyocytes. Aldosterone increased the levels of ANP and the cellular area of the cardiomyocytes; spironolactone reduced the aldosterone-increased ANP level and cellular area of cardiomyocytes. Aldosterone or spironolactone alone did not increase the level of cyclic 3',5'-adenosine monophosphate (cAMP), but aldosterone plus spironolactone led to increased cAMP level; the treatment with aldosterone + spironolactone + BAPTA-AM reduced the levels of cAMP. These data suggest that aldosterone-induced cAMP increase is independent of mineralocorticoid receptor (MR) and dependent on Ca(2+). Next, we have evaluated the role of A-kinase anchor proteins (AKAP) in the aldosterone-induced hypertrophic response. We have found that St-Ht31 (AKAP inhibitor) reduced the increased level of ANP which was induced by aldosterone; in addition, we have found an increase on protein kinase C (PKC) and extracellular signal-regulated kinase 5 (ERK5) activity when cells were treated with aldosterone alone, spironolactone alone and with a combination of both. Our data suggest that PKC could be responsible for ERK5 aldosterone-induced phosphorylation. Our study suggests that the aldosterone through its rapid effects promotes a hypertrophic response in cardiomyocytes that is controlled by an AKAP, being dependent on ERK5 and PKC, but not on cAMP/cAMP-dependent protein kinase signaling pathways. Lastly, we provide evidence that the targeting of AKAPs could be relevant in patients with aldosterone-induced cardiac hypertrophy and heart failure.

N-Acetyl Cysteine improves the diabetic cardiac function: possible role of fibrosis inhibition

Background

Diabetic cardiomyopathy is one of the leading causes of death in diabetes mellitus (DM) patients. This study aimed to explore the therapeutic implication of N-acetyl-L-cysteine (NAC, an antioxidant and glutathione precursor) and the possible underlying mechanism.

Methods

Thirty five 12-week-old male C57BL/6 mice were included. Twenty-five diabetic mice were induced by intraperitoneal injection of streptozocin (STZ, 150 mg/kg, Sigma-Aldrich) dissolved in a mix of citrate buffer after overnight fast. Mice with a blood glucose level above 13.5 mmol/L were considered diabetic. As a non-DM (diabetic) control, mice were injected with equal volume of citrate buffer. The 25 diabetic mice were divided into 5 groups with 5 animals in each group: including DM (diabetes without NAC treatment), and 4 different NAC treatment groups, namely NAC1, NAC3, NAC5 and NAC7, with the number defining the start time point of NAC treatment. In the 10 non-DM mice, mice were either untreated (Ctrl) or treated with NAC for 5 weeks (NAC only). Echocardiography was performed 12 weeks after STZ injection. Heart tissue were collected after echocardiography for Hematoxylin Eosin (HE) and Trichrome staining and ROS staining. Cardiac fibroblast cells were isolated, cultured and treated with high glucose plus NAC or the vehicle. qPCR analysis and CCK-8 assay were performed to observe fibrotic gene expression and cell proliferation.

Results

We found that both cardiac systolic function and diastolic function were impaired, coupled with excessive reactive oxygen stress and cardiac fibrosis 12 weeks after STZ induction. NAC significantly reduced ROS generation and fibrosis, together with improved cardiac systolic function and diastolic function. Strikingly, NAC1 treatment, which had the earlier and longer treatment, produced significant improvement of cardiac function and less fibrosis. In the cardiac fibroblasts, NAC blocked cardiac fibroblast proliferation and collagen synthesis induced by hyperglycemia.

Conclusions

Our study indicates that NAC treatment in diabetes effectively protects from diabetic cardiomyopathy, possibly through inhibiting the ROS production and fibrosis, which warrants further clarification.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-015-0076-3) contains supplementary material, which is available to authorized users.