Liquiritin Attenuates Lipopolysaccharides-Induced Cardiomyocyte Injury via an AMP-Activated Protein Kinase-Dependent Signaling Pathway.

Background: Liquiritin (LIQ) is a traditional Chinese medicine that has been reported to regulate inflammation, oxidative stress and cell apoptosis. However, the beneficial effects of LIQ in lipopolysaccharides (LPS)-induced septic cardiomyopathy (SCM) has not been reported. The primary goal of this study was to investigate the effects of LIQ in LPS-induced SCM model. Methods: Mice were pre-treated with LIQ for 7 days before they were injected with LPS (10 mg/kg) for inducing SCM model. Echocardiographic analysis was used to evaluate cardiac function after 12 h of LPS injection. Thereafter, mice were sacrificed to collect hearts for molecular and histopathologic assays by RT-PCR, western-blots, immunohistochemical and terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) staining analysis respectively. AMPKα2 knockout (AMPKα2-/-) mice were used to elucidate the mechanism of LIQ Neonatal rat cardiomyocytes (NRCMs) treated with or without LPS were used to further investigate the roles and mechanisms of LIQ in vitro experiments. Results: LIQ administration attenuated LPS-induced mouse cardiac dysfunction and reduced mortality, based upon the restoration of EF, FS, LVEDs, heart rate, dp/dt max and dp/dt min deteriorated by LPS treatment. LIQ treatment also reduced mRNA expression of TNFα, IL-6 and IL-1ß, inhibited inflammatory cell migration, suppressed cardiac oxidative stress and apoptosis, and improved metabolism. Mechanistically, LIQ enhanced the phosphorylation of AMP-activated protein kinase α2 (AMPKα2) and decreased the phosphorylation of mTORC1, IκBα and NFκB/p65. Importantly, the beneficial roles of LIQ were not observed in AMPKα2 knockout model, nor were they observed in vitro model after inhibiting AMPK activity with an AMPK inhibitor. Conclusion: We have demonstrated that LIQ exerts its protective effects in an SCM model induced by LPS administration. LIQ reduced inflammation, oxidative stress, apoptosis and metabolic alterations via regulating AMPKα2 dependent signaling pathway. Thus, LIQ might be a potential treatment or adjuvant for SCM treatment.

Resveratrol Inhibits Ischemia-Induced Myocardial Senescence Signals and NLRP3 Inflammasome Activation.

AIMS: The aim of this study was to investigate whether resveratrol (RSV) could ameliorate ischemia- and hypoxia-associated cardiomyocyte apoptosis and injury via inhibiting senescence signaling and inflammasome activation. MATERIALS AND METHODS: Mice were treated with RSV by gastric tube (320 mg/kg/day) or vehicle one week before left coronary artery ligation or sham surgery until the end of the experiments. After pressure-volume loop analysis, mouse hearts were harvested for histopathological (including PSR, TTC, TUNEL staining, immunohistochemistry, and immunofluorescence) and molecular analysis by western blotting and RT-PCR. In addition, neonatal rat cardiomyocytes (NRCMs), cardiac fibroblasts (CFs), and macrophages were isolated for in vitro experiments. Key Findings. RSV treatment decreased mortality and improved cardiac hemodynamics. RSV inhibited the expression of senescence markers (p53, p16, and p19), inflammasome markers (NLRP3 and Cas1 p20), and nuclear translocation of NF-κB, hence alleviating infarction area, fibrosis, and cell apoptosis. RSV also inhibited expression of interleukin- (IL-) 1ß, IL-6, tumor necrosis factor-α, and IL-18 in vivo. In in vitro experiment, RSV prevented hypoxia-induced NRCM senescence and apoptosis. After inhibition of sirtuin 1 (Sirt1) by EX27, RSV failed to inhibit p53 acetylation and expression. Moreover, RSV could inhibit expression of NLRP3 and caspase 1 p20 in NRCMs, CFs, and macrophages, respectively, in in vitro experiments. Significance. Our findings revealed that RSV protected against ischemia-induced mouse heart injury in vivo and hypoxia-induced NRCM injury in vitro via regulating Sirt1/p53-mediated cell senescence and inhibiting NLRP3-mediated inflammasome activation.

Leukocyte immunoglobulin-like receptor B4 protects against cardiac hypertrophy via SHP-2-dependent inhibition of the NF-κB pathway.

Cardiac hypertrophy is a complex pathological process, and the molecular mechanisms underlying hypertrophic remodeling have not been clearly elucidated. Leukocyte immunoglobulin-like receptor B4 (lilrb4) is an inhibitory transmembrane protein that is necessary for the regulation of various cellular signaling pathways. To investigate whether lilrb4 plays a role in cardiac hypertrophy, we performed aortic banding in lilrb4 knockout mice, lilrb4 cardiac-specific transgenic mice, and their wild-type littermates. Cardiac hypertrophy was evaluated by echocardiographic, hemodynamic, pathological, and molecular analyses. We found that lilrb4 was expressed both in myocardial tissue and on cultured cardiomyocytes under basal conditions, but the expression was obviously decreased in mouse hearts following aortic banding and in cardiomyocytes treated with angiotensin II. Lilrb4 disruption aggravated cardiac hypertrophy, fibrosis, and dysfunction in response to pressure overload. Conversely, the cardiac overexpression of lilrb4 led to the opposite effects. Moreover, lilrb4 overexpression inhibited angiotensin II-induced cardiomyocyte hypertrophy in vitro. Mechanistically, we determined that the cardioprotective effect of lilrb4 was mediated through an interaction with SHP-2, the preservation of phosphorylated SHP-2, and the inhibition of the NF-κB pathway. In addition, SHP-2 knockdown in cardiomyocytes eliminated the inhibitory effects of lilrb4 on angiotensin II-induced hypertrophy and NF-κB activation. Our results suggest that lilrb4 protects against pathological cardiac hypertrophy via the SHP-2-dependent inhibition of the NF-κB pathway and may act as a potential therapeutic target for cardiac hypertrophy. KEY MESSAGES: Lilrb4 expression is decreased by hypertrophic stimuli. Lilrb4 protects against pathological cardiac hypertrophy. Lilrb4 interacts with SHP-2 and inhibits NF-κB pathway.

Piperine Alleviates Doxorubicin-Induced Cardiotoxicity via Activating PPAR-γ in Mice.

BACKGROUND: Oxidative stress, inflammation and cardiac apoptosis were closely involved in doxorubicin (DOX)-induced cardiac injury. Piperine has been reported to suppress inflammatory response and pyroptosis in macrophages. However, whether piperine could protect the mice against DOX-related cardiac injury remain unclear. This study aimed to investigate whether piperine inhibited DOX-related cardiac injury in mice. METHODS: To induce DOX-related acute cardiac injury, mice in DOX group were intraperitoneally injected with a single dose of DOX (15 mg/kg). To investigate the protective effects of piperine, mice were orally treated for 3 weeks with piperine (50 mg/kg, 18:00 every day) beginning two weeks before DOX injection. RESULTS: Piperine treatment significantly alleviated DOX-induced cardiac injury, and improved cardiac function. Piperine also reduced myocardial oxidative stress, inflammation and apoptosis in mice with DOX injection. Piperine also improved cell viability, and reduced oxidative damage and inflammatory factors in cardiomyocytes. We also found that piperine activated peroxisome proliferator-activated receptor-γ (PPAR-γ), and the protective effects of piperine were abolished by the treatment of the PPAR-γ antagonist in vivo and in vitro. CONCLUSIONS: Piperine could suppress DOX-related cardiac injury via activation of PPAR-γ in mice.

T-bet deficiency attenuates cardiac remodelling in rats.

Previous studies have suggested the involvement of CD4 + T lymphocytes in cardiac remodelling. T-bet can direct Th1 lineage commitment. This study aimed to investigate the functional significance of T-bet in cardiac remodelling induced by pressure overload using T-bet global knockout rats. Increased T-bet levels were observed in rodent and human hypertrophied hearts. T-bet deficiency resulted in a less severe hypertrophic phenotype in rats. CD4 + T-lymphocyte reconstitution in T-bet-/- rats resulted in aggravated cardiac remodelling. T-cell homing molecule expression and cytokine secretion were altered in T-bet-deficient rat hearts. Administration of exogenous interferon-γ (IFN-γ) offset T-bet deficiency-mediated cardioprotection. Cardiomyocytes cultured in T-bet-/- CD4 + T-cell-conditioned media showed a reduced hypertrophic response after hypertrophic stimuli, which was abolished by an IFN-γ-neutralizing antibody. Taken together, our findings show that T-bet deficiency attenuates pressure overload-induced cardiac remodelling in rats. Specifically, targeting T-bet in T cells may be of great importance for the treatment of pathological cardiac remodelling and heart failure.

Cucurbitacin B Protects Against Pressure Overload Induced Cardiac Hypertrophy.

Lack of effective anti-cardiac hypertrophy drugs creates a major cause for the increasing prevalence of heart failure. In the present study, we determined the anti-hypertrophy and anti-fibrosis potential of a natural plant triterpenoid, Cucurbitacin B both in vitro and in vivo. Aortic banding (AB) was performed to induce cardiac hypertrophy. After 1 week of surgery, mice were receive cucurbitacin B treatment (Gavage, 0.2 mg/kg body weight/2 day). After 4 weeks of AB, cucurbitacin B demonstrated a strong anti-hypertrophy and -fibrosis ability as evidenced by decreased of heart weight, myocardial cell cross-sectional area and interstitial fibrosis, ameliorated of systolic and diastolic abnormalities, normalized in gene expression of hypertrophic and fibrotic markers, reserved microvascular density in pressure overload induced hypertrophic mice. Cucurbitacin B also showed significant hypertrophy inhibitory effect in phenylephrine stimulated cardiomyocytes. The Cucurbitacin B-mediated mitigated cardiac hypertrophy was attributable to the increasing level of autophagy, which was associated with the blockade of Akt/mTOR/FoxO3a signal pathway, validated by SC79, MK2206, and 3-MA, the Akt agonist, inhibitor and autophagy inhibitor in vitro. The overexpression of constitutively active Akt completely abolished the Cucurbitacin B-mediated protection of cardiac hypertrophy in human cardiomyocytes AC16. Collectively, our findings suggest that cucurbitacin B protects against cardiac hypertrophy through increasing the autophagy level in cardiomyocytes, which is associated with the inhibition of Akt/mTOR/FoxO3a signal axis. J. Cell. Biochem. 118: 3899-3910, 2017. © 2017 Wiley Periodicals, Inc.

Evodiamine attenuates TGF-ß1-induced fibroblast activation and endothelial to mesenchymal transition.

The aim of this study is to investigate the effect of evodiamine on fibroblast activation in cardiac fibroblasts and endothelial to mesenchymal transition (EndMT) in human umbilical vein endothelial cells (HUVECs). Neonatal rat cardiac fibroblasts were stimulated with transforming growth factor beta 1 (TGF-ß1) to induce fibroblast activation. After co-cultured with evodiamine (5, 10 µM), the proliferation and pro-fibrotic proteins expression of cardiac fibroblasts were evaluated. HUVECs were also stimulated with TGF-ß1 to induce EndMT and treated with evodiamine (5, 10 µM) at the same time. The EndMT response in the HUVECs was evaluated as well as the capacity of the transitioned endothelial cells migrating to surrounding tissue. As a result, Evodiamine-blunted TGF-ß1 induced activation of cardiac fibroblast into myofibroblast as assessed by the decreased expressions of α-SMA. Furthermore, evodiamine reduced the increased protein expression of fibrosis markers in neonatal and adult rat cardiac fibroblasts induced by TGF-ß1. HUVECs stimulated with TGF-ß1 exhibited lower expression levels of CD31, CD34, and higher levels of α-SMA, vimentin than the control cells. This phenotype was eliminated in the HUVECs treated with both 5 and 10 µM evodiamine. Evodiamine significantly reduced the increase in migration ability that occurred in response to TGF-ß1 in HUVECs. In addition, the activation of Smad2, Smad3, ERK1/2, and Akt, and the nuclear translocation of Smad4 in both cardiac fibroblasts and HUVEC were blocked by evodiamine treatment. Thus, evodiamine could prevent cardiac fibroblasts from activation into myofibroblast and protect HUVEC against EndMT. These effects may be mediated by inhibition of the TGFß pathway in both cardiac fibroblasts and HUVECs.

Evodiamine Prevents Isoproterenol-Induced Cardiac Fibrosis by Regulating Endothelial-to-Mesenchymal Transition.

Evodiamine, a major component of Evodia rutaecarpa, can protect the myocardium against injury induced by atherosclerosis and ischemia-reperfusion. However, the effect of evodiamine against cardiac fibrosis remains unclear. This study aims to investigate the possible effect and mechanism involved in the function of evodiamine on isoproterenol-induced cardiac fibrosis and endothelial-to-mesenchymal transition. Isoproterenol was used to induce cardiac fibrosis in mice, and evodiamine was gavaged simultaneously. After 14 days, cardiac function was accessed by echocardiography. The extent of cardiac fibrosis and hypertrophy was evaluated by pathological and molecular analyses. The extent of endothelial-to-mesenchymal transition was evaluated by the expression levels of CD31, CD34, α-smooth muscle actin, and vimentin by immunofluorescence staining and Western blot analysis. After 14 days, the heart weight/body weight ratio and heart weight/tibia length ratio revealed no significant difference between the isoproterenol group and the isoproterenol/evodiamine-treated groups, whereas the increased heart weight was reduced in the isoproterenol/evodiamine-treated groups. Echocardiography revealed that interventricular septal thickness and left ventricular posterior wall thickness at the end diastole decreased in the evodiamine-treated groups. Evodiamine reduced isoproterenol-induced cardiac fibrosis as accessed by normalization in collagen deposition and gene expression of hypertrophic and fibrotic markers. Evodiamine also prevented endothelial-to-mesenchymal transition as evidenced by the increased expression levels of CD31 and CD34, decreased expression levels of α-smooth muscle actin and vimentin, and increased microvascular density in the isoproterenol/evodiamine-treated mice hearts. Furthermore, isoproterenol-induced activation of transforming growth factor-ß1/Smad signal was also blunted by evodiamine. Therefore, evodiamine may prevent isoproterenol-induced cardiac fibrosis by regulating endothelial-to-mesenchymal transition, which is probably mediated by the blockage of the transforming growth factor-ß1/Smad pathway.

Mnk1 (Mitogen-Activated Protein Kinase-Interacting Kinase 1) Deficiency Aggravates Cardiac Remodeling in Mice.

Identifying the key factor involved in cardiac remodeling is critically important for developing novel strategies to protect against heart failure. Here, the role of Mnk1 (mitogen-activated protein kinase-interacting kinase 1) in cardiac remodeling was clarified. Cardiac remodeling was induced by transverse aortic constriction in Mnk1-knockout mice and their wild-type control mice. After 4 weeks of transverse aortic constriction, Mnk1-knockout mice developed exaggerated cardiac hypertrophy, fibrosis, dysfunction, and cardiomyocyte apoptosis and showed increased ERK1/2 (extracellular signal-regulated kinase 1/2) activation along with reduced sprouty2 expression. In line with the in vivo studies, Mnk1 knockdown by Mnk1 siRNA transfection induced exaggerated angiotensin II-induced cardiomyocyte hypertrophy in neonatal rat ventricular myocytes (NRVMs). Moreover, adenovirus-mediated overexpression of Mnk1 in NRVMs protected cardiomyocytes from angiotensin II-induced hypertrophy. In addition, overexpression of sprouty2 rescued NRVMs with Mnk1 knockdown from angiotensin II-induced hypertrophy. In accordance with the in vivo studies, as compared with the control group, Mnk1 knockdown led to hyperphosphorylation of ERK1/2 and suppression of the sprouty2 expression in angiotensin II-treated NRVMs; furthermore, Mnk1 overexpression led to hypophosphorylation of ERK1/2 in angiotensin II-treated NRVMs. In addition, sprouty2 overexpression suppressed the activation of ERK1/2 in angiotensin II-treated NRVMs with Mnk1 knockdown. Impressively, MnK1-knockout mice with overexpression of sprouty2 exhibited signs of a blunted cardiac hypertrophic response. Mnk1 likely carries out a suppressive function in cardiac hypertrophy via regulating the sprouty2/ERK1/2 pathway. It implicates Mnk1 in the development of cardiac remodeling.

OX40 regulates pressure overload-induced cardiac hypertrophy and remodelling via CD4+ T-cells.

OX40, which belongs to the tumour necrosis factor (TNF)-receptor family, is a costimulatory receptor that can potentiate T-cell receptor signalling on the surface of T-lymphocytes. The role of OX40 in non-immune systems, particularly the cardiovascular system, has not been defined. In the present study, we observed a noticeable increase in OX40 expression during cardiac remodelling in rodent heart. In the present study, cardiac hypertrophy was induced by aortic banding (AB) in OX40 knockout (KO) mice and wild-type (WT) mice. After 8 weeks, the OX40 KO mice showed significantly attenuated cardiac hypertrophy, fibrosis and inflammation as well as preserved cardiac function compared with the WT mice. Follow-up in vitro studies suggested that CD4+ T-lymphocyte proliferation and pro-inflammatory cytokine release were significantly decreased, whereas anti-inflammatory cytokine release was considerably increased in OX40 KO mice compared with WT mice as assessed by Cell Counting Kit-8 (CCK-8) assay and ELISA. Co-culturing neonatal rat cardiomyocytes with the activated supernatant of CD4+ T-lymphocytes from OX40 KO mice reduced the hypertrophy response. Interestingly, OX40 KO mice with reconstituted CD4+ T-lymphocytes presented deteriorated cardiac remodelling. Collectively, our data indicate that OX40 regulates cardiac remodelling via the modulation of CD4+ T-lymphocytes.

Nobiletin attenuates cardiac dysfunction, oxidative stress, and inflammatory in streptozotocin: induced diabetic cardiomyopathy.

Diabetic cardiomyopathy, characterized by the presence of diastolic and/or systolic myocardial dysfunction, is one of the major causes of heart failure. Nobiletin, which is extracted from the fruit peel of citrus, is reported to possess anti-inflammatory, anti-oxidative, and hypolipidemic properties. The purpose of this study was to investigate whether nobiletin exerts the therapeutic effect on streptozotocin-induced diabetic cardiomyopathy (DCM) in mice. 80 experimental male C57BL mice were randomly assigned into four groups: sham + vehicle (VEH/SH), sham + nobiletin (NOB/SH), DCM + vehicle (VEH/DM), and DCM + nobiletin (NOB/DM). Nobiletin treatment ameliorated cardiac dysfunction in the DCM group, as shown by the result of echocardiography and hemodynamic measurements. Nobiletin treatment also blunted the mRNA expression of NADPH oxidase isoforms p67(phox), p22(phox), and p91(phox), and abated oxidative stress. Although administration of diabetic mice with nobiletin did not significantly effect the level of blood glucose, it decreased the TGF-ß1, CTGF, fibronectin, and collagen Iα expressions and blunted cardiac fibrosis. In addition, nobiletin inhibited the activation of c-Jun NH2-terminal kinase (JNK), P38, and NF-κB in the cardiac tissue of diabetic mice. Collectively, our study indicates that treatment with nobiletin mitigates cardiac dysfunction and interstitial fibrosis, and these beneficial of nobiletin may belong to the suppression of JNK, P38, and NF-κB signaling pathways.

Protection against cardiac hypertrophy by geniposide involves the GLP-1 receptor / AMPKα signalling pathway.

BACKGROUND AND PURPOSE: Activation of glucagon-like peptide-1 (GLP-1) receptor exerts a range of cardioprotective effects. Geniposide is an agonist of GLP-1 receptor, but its role in cardiac hypertrophy remains completely unknown. Here, we have investigated its protective effects and clarified the underlying molecular mechanisms. EXPERIMENTAL APPROACH: The transverse aorta was constricted in C57/B6 mice and then geniposide was given orally for 7 weeks. Morphological changes, echocardiographic parameters, histological analyses and hypertrophic markers were used to evaluate hypertrophy. KEY RESULTS: Geniposide inhibited the hypertrophic response induced by constriction of the transverse aorta or by isoprenaline. Activation of 5'-AMP-activated protein kinase-α (AMPKα) and inhibition of mammalian target of rapamycin, ERK and endoplasmic reticulum stress were observed in hypertrophic hearts that were treated with geniposide. Furthermore, Compound C (CpC) or knock-down of AMPKα restricted protection of geniposide against cell hypertrophy and activation of mammalian target of rapamycin and ERK induced by hypertrophic stimuli. CpC or shAMPKα also abolished the protection of geniposide against endoplasmic reticulum stress induced by thapsigargin or dihtiothreitol. The cardio-protective effects of geniposide were ablated in mice subjected to CpC. GLP-1receptor blockade counteracted the anti-hypertrophic response and activation of AMPKα by geniposide. Knock-down of GLP-1 receptor also offset the inhibitory effects of geniposide on cardiac hypertrophy in vivo. CONCLUSIONS AND IMPLICATIONS: Geniposide protected against cardiac hypertrophy via activation of the GLP-1 receptor/AMPKα pathway. Geniposide is a potential therapeutic drug for cardiac hypertrophy.

Puerarin attenuates the inflammatory response and apoptosis in LPS-stimulated cardiomyocytes.

Patients with septic shock suffer from high mortality rates, particularly when complicated by severe myocardial depression which is characterized by hypotension and a reduction in cardiac output. Inflammation is an important factor involved in the early stages of sepsis. The aim of the present study was to investigate the effect of the Chinese herbal compound puerarin (1, 5, 10, 20 and 40 µM) on cardiomyocyte inflammatory response in a sepsis model using H9c2 cardiomyocytes stimulated with 1 µg/ml lipopolysaccharide (LPS). The mRNA expression levels of tumor necrosis factor (TNF)-α and interleukin (IL)-ß were evaluated using reverse transcription-quantitative polymerase chain reaction. In addition, the protein expression levels of various factors were determined using western blot analysis. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling was used to evaluate the apoptosis rates in the various groups, and immunocytochemical analysis was employed to determine the effect of puerarin on the nuclear translocation of p65 protein. The present study demonstrated that LPS stimulation increased IL-1ß and TNF-α mRNA expression levels, as compared with the controls (P<0.05). Following treatment with various concentrations of puerarin, the expression levels of IL-1ß and TNF-α were markedly blunted, particularly in the LPS + 40 µM puerarin group (P<0.05 vs. the LPS group). Furthermore, puerarin administration significantly inhibited LPS-induced apoptosis in H9c2 cardiomyocytes, as determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining (TUNEL positive cells: LPS + 40 µM puerarin group, 5.5% vs. LPS group, 10.5%; P<0.01). In addition, puerarin significantly decreased LPS-induced phosphorylated nuclear factor (p-NF)-κB p65 and Bax expression levels, and increased the expression levels of Bcl-2, as compared with the LPS group (P<0.05). These data indicated that puerarin may serve as a valuable protective agent against cardiovascular inflammatory diseases.

Shensongyangxin protects against pressure overload­induced cardiac hypertrophy.

Shensongyangxin (SSYX) is a medicinal herb, which has long been used in traditional Chinese medicine. Various pharmacological activities of SSYX have been identified. However, the role of SSYX in cardiac hypertrophy remains to be fully elucidated. In present study, aortic banding (AB) was performed to induce cardiac hypertrophy in mice. SSYX (520 mg/kg) was administered by daily gavage between 1 and 8 weeks following surgery. The extent of cardiac hypertrophy was then evaluated by pathological and molecular analyses of heart tissue samples. In addition, in vitro experiments were performed to confirm the in vivo results. The data of the present study demonstrated that SSYX prevented the cardiac hypertrophy and fibrosis induced by AB, as assessed by measurements of heart weight and gross heart size, hematoxylin and eosin staining, cross­sectional cardiomyocyte area and the mRNA expression levels of hypertrophic markers. SSYX also inhibited collagen deposition and suppressed the expression of transforming growth factor ß (TGFß), connective tissue growth factor, fibronectin, collagen Ⅰα and collagen Ⅲα, which was mediated by the inhibition of the TGFß/small mothers against decapentaplegic (Smad) signaling pathway. The inhibitory action of SSYX on cardiac hypertrophy was mediated by the inhibition of Akt signaling. In vitro investigations in the rat H9c2 cardiac cells also demonstrated that SSYX attenuated angiotensin II­induced cardiomyocyte hypertrophy. These findings suggested that SSYX attenuated cardiac hypertrophy and fibrosis in the pressure overloaded mouse heart. Therefore, the cardioprotective effect of SSYX is associated with inhibition of the Akt and TGFß/Smad signaling pathways.

Toll-like receptor 5 deficiency attenuates interstitial cardiac fibrosis and dysfunction induced by pressure overload by inhibiting inflammation and the endothelial-mesenchymal transition.

Vascular dysfunction, characterized by the endothelial-to-mesenchymal transition (EndMT), contributes to the development of cardiac fibrosis induced by pressure overload. Toll-like receptor (TLR)5 is a member of the TLR family that is expressed on not only immune cells but also nonimmune cells including cardiomyocytes and vascular endothelial cells. The level of TLR5 expression on endothelial cells is low under normal circumstances but is increased in response to stimuli such as pressure overload. The aim of this study was to investigate the importance of TLR5 in cardiac endothelial dysfunction during the development of cardiac fibrosis induced by pressure overload. Global TLR5-deficient mice and wild-type littermates underwent aortic banding (AB) for 8weeks to induce cardiac fibrosis, hypertrophy and dysfunction. The deficiency of TLR5 in this model exerted no basal effects but attenuated the cardiac fibrosis, hypertrophy and dysfunction induced by pressure overload. AB-induced endothelial TLR5 activation enhanced the development of cardiac fibrosis independent of cardiomyocyte hypertrophy and triggered left ventricular dysfunction. TLR5-deficient mice also exhibited ameliorated myocardial pro-inflammatory cytokine expression and macrophage infiltration and inhibited the EndMT, all of which contribute to the development of cardiac fibrosis. These findings suggest that TLR5 triggers inflammatory responses and promotes the EndMT, which may be an important mechanism underlying the promotion of cardiac fibrosis and left ventricular dysfunction during pressure overload.

Oleanolic acid alleviated pressure overload-induced cardiac remodeling.

Previous study has demonstrated that oleanolic acid (OA) possessing the anti-inflammatory and anti-oxidant properties blunted high-glucose-induced diabetic cardiomyopathy and ameliorated experimental autoimmune myocarditis in mice. However, little is known about its effects on pressure overload-induced cardiac remodeling. Herein, we investigated the effect of OA on cardiac remodeling and underlying mechanism. Mice, subjected to aortic banding (AB), were randomly assigned into control group and experimental group. OA premixed in diets was administered to mice after 3 days of AB. Echocardiography and catheter-based measurements of hemodynamic parameters were performed after 8 weeks' treatment of OA. Histologic examination and molecular analyses were used to assess cardiac hypertrophy and tissue fibrosis. In addition, the inhibitory effects of OA on H9c2 cardiomyocytes and cardiac primary fibroblast responded to the stimulation of AngII were also investigated. OA ameliorated the systolic and diastolic dysfunction induced by pressure overload evidenced by echocardiography and catheter-based measurements. OA also decreased the mRNA expression of cardiac hypertrophy and fibrosis markers evidenced by RT-PCR. It has been shown in our study that pressure overload activated the phosphorylations of Akt, mTOR, p70s6k, S6, GSK3ß, and FoxO3a, and treatment of OA attenuated the phosphorylation of these proteins. In addition, hypertrophy of cardiomyocytes and fibrosis markers induced by AngII was inhibited by OA in vitro. Our findings uncover that OA suppressed AB-induced cardiac hypertrophy, partly by inhibiting the activity of Akt/mTOR pathway, and suggest that treatment of OA may have a benefit on retarding the progress of cardiac remodeling under long terms of pressure overload.

Sanguinarine inhibits angiotensin II-induced apoptosis in H9c2 cardiac cells via restoring reactive oxygen species-mediated decreases in the mitochondrial membrane potential.

Cell apoptosis induced by Angiotensin II (Ang II) has a critical role in the development of cardiovascular diseases. The aim of the present study was to investigate whether sanguinarine (SAN), a drug which was proved to have anti­oxidant, anti­proliferative and immune enhancing effects, can abolish cell apoptosis induced by Ang II. In the present study, H9c2 cardiac cells were stimulated with 10 µM Ang II with or without SAN. The level of intracellular reactive oxygen species (ROS) generation was assessed using dichlorodihydrofluorescein diacetate, and changes of the mitochondrial membrane potential (MMP) were assessed using JC­1 staining. Furthermore, mRNA expression of NOX2 was determined by reverse transcription quantitative polymerase chain reaction, and apoptosis was detected by Annexin V/propidium iodide staining and flow cytometry. The expression of B­cell lymphoma 2 (Bcl­2), Bcl­2­associated X protein (Bax) as well as cleaved (c)­caspase 3 and ­9 were detected by western blot analysis, and the activity of caspase 3 and ­9 was detected using an ELISA. The results of the present study showed that NOX2 expression and ROS generation induced by Ang II were inhibited by SAN, and the Ang 2­induced MMP loss was also ameliorated. Furthermore, Ang II­induced H9c2 cardiac cell apoptosis as well as c­caspase 3 and ­9 levels were significantly reduced by SAN. Investigation of the possible pathway involved in the anti­apoptotic effect of SAN showed that the expression of Bcl­2 was decreased, while that of Bax was increased following stimulation with Ang II, which was reversed following treatment with SAN. In addition, Ang II enhanced the activity of caspase 9 and cleaved downstream caspases such as caspase­3, initiating the caspase cascade, while pre­treatment of H9c2 cardiac cells with SAN blocked these effects. In conclusion, the findings of the present study indicated that SAN inhibits the apoptosis of H9c2 cardiac cells induced by Ang II, most likely via restoring ROS­mediated decreases of the MMP.

3,3'-Diindolylmethane attenuates cardiac H9c2 cell hypertrophy through 5'-adenosine monophosphate-activated protein kinase-α.

3,3'-Diindolylmethane (DIM) is the major product of the acid-catalyzed condensation of indole-3-carbinol (I3C), a component of extracts of Brassica food plants. Numerous studies have suggested that DIM has several beneficial biological activities, including elimination of free radicals, antioxidant and anti-angiogenic effects and activation of apoptosis of various tumor cells. In the present study, an in vitro model was established, using 1 µM angiotensin II (Ang II) in cultured rat cardiac H9c2 cells, to observe the effects of DIM on cardiac hypertrophy. Following 24 h stimulation with DIM (1, 5, and 10 µM) with or without Ang II, cells were characterized by immunofluorescence to analyze cardiac α-actinin expression. Cardiomyocyte hypertrophy and molecular markers of cardiac hypertrophy were assessed by quantitative polymerase chain reaction. Atrial natriuretic peptide, brain natriuretic peptide and myosin heavy chain ß mRNA expression were induced by Ang II in H9c2 cells treated with the optimal concentration of DIM for 6, 12, and 24 h. The levels of phosphorylated and total proteins of the 5' AMP-activated protein kinase α (AMPKα)/mitogen-activated protein kinase (MAPK)/mechanistic target of rapamycin (mTOR) signaling pathways in H9c2 cells treated with DIM for 0, 15, 30, and 60 min induced by Ang II were determined by western blot analysis. The results showed that DIM attenuated cellular hypertrophy in vitro, enhanced the phosphorylation of AMPKα and inhibited the MAPK­mTOR signaling pathway in response to hypertrophic stimuli.