Yingli Yu

Ginsenoside RK3 Prevents Hypoxia-Reoxygenation Induced Apoptosis in H9c2 Cardiomyocytes via AKT and MAPK Pathway

Reperfusion therapy is widely utilized for acute myocardial infarction (AMI), but further injury induced by rapidly initiating reperfusion of the heart is often encountered in clinical practice. Ginsenoside RK3 (RK3) is reportedly present in the processed Radix notoginseng that is often used as a major ingredient of the compound preparation for ischemic heart diseases. This study aimed to investigate the possible protective effect of RK3 against hypoxia-reoxygenation (H/R) induced H9c2 cardiomyocytes damage and its underlying mechanisms. Our results showed that RK3 pretreatment caused increased cell viability and decreased levels of LDH leakage compared with the H/R group. Moreover, RK3 pretreatment inhibited cell apoptosis, as evidenced by decreased caspase-3 activity, TUNEL-positive cells, and Bax expression, as well as increased Bcl-2 level. Further mechanism investigation revealed that RK3 prevented H9c2 cardiomyocytes injury and apoptosis induced by H/R via AKT/Nrf-2/HO-1 and MAPK pathways. These observations indicate that RK3 has the potential to exert cardioprotective effects against H/R injury, which might be of great importance to clinical efficacy for AMI treatment.

Cardioprotective effects of Notoginsenoside R1 against ischemia/reperfusion injuries by regulating oxidative stress- and endoplasmic reticulum stress- related signaling pathways

Background: Recent reports suggested the involvement of oxidative stress- and endoplasmic reticulum stress (ERS)-associated pathways in the progression of ischemia/reperfusion (I/R) injury. Notoginsenoside R1 (NGR1) is a novel saponin isolated from P. notoginseng, which has a history of prevention and treatment of cardiovascular diseases. Objective: We aimed to examine the cardioprotective effects of NGR1 on I/R-induced heart dysfunction ex vivo and in vitro. Methods: H9c2 cadiomyocytes were incubated with NGR1 for 24 h and exposed to hypoxia/reoxygenation. Isolated rat hearts were perfused by NGR1 for 15 min and then subjected to global ischemia/reperfusion. Hemodynamic parameters were monitored as left ventricular systolic pressure (LVSP), heart rate, and maximal rate of increase and decrease of left ventricular pressure (±dP/dt max/min). Results: NGR1 pretreatment prevents cell apoptosis and delays the onset of ERS by decreasing the protein expression levels of ERS-responsive proteins GRP78, P-PERK, ATF6, IRE, and inhibiting the expression of pro-apoptosis proteins CHOP, Caspase-12, and P-JNK. Besides, NGR1 scavenges free radical, and increases the activity of antioxidase. NGR1 inhibits Tunicamycin-induced cell death and cardic dysfunction. Conclusion: We elucidated the significant cardioprotective effects of NGR1 against I/R injuries, and demonstrated the involvement of oxidative stress and ERS in the protective effects of NGR1.

Isorhamnetin Attenuates Atherosclerosis by Inhibiting Macrophage Apoptosis via PI3K/AKT Activation and HO-1 Induction

Background and Purpose Isorhamnetin (Iso) is a flavonoid compound extracted from the Chinese herb Hippophae rhamnoides L. Previous studies have revealed its anti-cancer, anti-inflammatory, and anti-oxidant activities. This study investigated the ability of Iso to inhibit oxidized low-density lipoprotein (ox-LDL)-induced cell apoptosis in THP-1-derived macrophages. The effects of Iso on atherosclerosis in vivo were also evaluated in apolipoprotein E knockout (ApoE-/-) mice fed a high fat diet. Methods and Results Iso showed significant inhibitory effects on ox-LDL-induced THP-1-derived macrophage injuries via decreasing reactive oxygen species levels, lipid deposition, and caspase-3 activation, restoring mitochondrial membrane potential, reducing the number of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive cells, and regulating apoptosis-related proteins. We also determined the protective effects of Iso by PI3K/AKT activation and HO-1 induction. Iso reduced the atherosclerotic plaque size in vivo in ApoE-/- mice as assessed by oil red O, Sudan IV staining, and CD68-positive cells, and reduced macrophage apoptosis as assessed by caspase-3 and TUNEL assays in lesions. Conclusion In conclusion, our results show that Iso inhibited atherosclerotic plaque development in ApoE-/- mice by PI3K/AKT activation and HO-1 induction.

Elatoside C protects the heart from ischaemia/reperfusion injury through the modulation of oxidative stress and intracellular Ca2 + homeostasis

BACKGROUND We have previously shown that Elatoside C reduces cardiomyocyte apoptosis during ischaemia/reperfusion (I/R). Here, we investigated whether Elatoside C improves heart function in isolated rat hearts subjected to I/R and elucidated the potential mechanisms involved in Elatoside C-induced protection. METHODS AND RESULTS Isolated rat hearts were subjected to global ischaemia followed by reperfusion in the absence or presence of Elatoside C. We found that Elatoside C significantly attenuated cardiac dysfunction and depressed oxidative stress induced by I/R. Consistently, Elatoside C prevented I/R-induced mitochondrial dysfunction, which was evident by the inhibition of mitochondrial ROS production, mitochondrial permeability transition pore (mPTP) opening, cytochrome c release from the mitochondria and Bax translocation. Moreover, Elatoside C improved abnormal calcium handling during I/R, including increasing sarcoplasmic reticulum Ca(2+) ATPase (SERCA2) activity, alleviating [Ca(2+)]ER depletion, and reducing the expression levels of ER stress protein markers. All of these protective effects of Elatoside C were partially abolished by the PI3K/Akt inhibitor LY294002, ERK1/2 inhibitor PD98059, and JAK2/STAT3 inhibitor AG490. Further assessment in isolated cardiomyocytes showed that Elatoside C maintained the Ca(2+) transients and cell shortening against I/R. CONCLUSIONS Elatoside C protects against cardiac injury during I/R by attenuating oxidative stress and [Ca(2+)]i overload through the activation of both the reperfusion injury salvage kinase (RISK) pathway (including PI3K/Akt and ERK1/2) and the survivor activating factor enhancement (SAFE) pathway (including JAK2/STAT3) and, subsequently, inhibiting the opening of mPTPs.

Total aralosides of aralia elata (Miq) seem (TASAES) ameliorate nonalcoholic steatohepatitis by modulating IRE1α-mediated JNK and NF-κB pathways in ApoE–/– mice

ETHNOPHARMACOLOGICAL RELEVANCE Total saponins of Aralia elata (Miq) Seem (TASAES) from the Chinese traditional herb Long ya Aralia chinensis L. is popularly used as a folk medicine to treat rheumatism, neurasthenia, diabetes, hepatitis and antivirus in Asian countries. However, there was poor study of TASAES on Non-alcoholic steatohepatitis (NASH), which is characterized by inflammatory responses and hepatocellular apoptosis exacerbating liver injury. This study aimed to clarify whether or not the anti-inflammatory and anti-apoptotic activities and protective mechanisms of the total aralosides of Aralia elata (Miq) Seem (TASAES) ameliorate NASH in a high-fat diet (HFD)-induced ApoE-/- mouse model. MATERIAL AND METHODS C57/BL6N and ApoE-/- mice were fed with HFD containing 0.3% cholesterol and 20% fat to induce NASH and then treated with TASAES (75,150mg/kg/day, i.g.) for 12 weeks. Liver tissue was procured for histological examination, real-time RT-PCR and Western blot analysis. RESULTS ASAES treatment groups exhibited lower serum alanine and aspartate aminotransferases than the NASH group. TASAES could also reduce hepatic steatosis, as revealed by histological changes. In addition, TASAES treatment groups showed lower protein and mRNA expression levels of pro-inflammatory cytokines, such as IL-6, MCP-1, and TNF-α than NASH group. Reduced TUNEL-positive cells were also found in TASAES treatment groups. Western blot and immunohistochemical results indicated that TASAES regulated apoptosis and inflammation-related protein expression. Furthermore, TASAES treatment significantly reduced the phosphorylation of IRE1α, JNK and IκB and the downstream activation of NF-κB p65 was also reduced. CONCLUSION These findings suggested that the ameliorative effects of TASASE in HFD-induced NASH were associated with the regulation of IRE1α-mediated JNK and NF-κB signal pathways, thereby protecting the liver against NASH.

Tin Compensation for the SnS Based Optoelectronic Devices

In this paper we report the growth of high quality SnS thin films with good crystallinity deposited on two-dimensional (2D) mica substrates. It is believed that the 2D nature of SnS, with strong intra-layer covalent bonds and weak inter-layer van der Waals interactions, is responsible for its relative insensitivity to lattice mismatch. We also investigated the reduction of Sn vacancies in the material using Sn-compensation technique during the material growth process. The experimental results clearly demonstrated substantial enhancements in the electrical and structural properties for films deposited using Sn-compensation technique. A mobility of 51 cm2  V−1 s−1 and an XRD rocking curve full width at half maximum of 0.07° were obtained. Sn-compensated SnS/GaN:Si heterojunctions were fabricated and significant improvement in both the I-V characteristics and the spectral responsivities of the devices were characterized.

Salvianolic Acid A Protects H9c2 Cells from Arsenic Trioxide-Induced Injury via Inhibition of the MAPK Signaling Pathway

Background/Aims: This study aimed to investigate whether Salvianolic acid A (Sal A) conferred cardiac protection against Arsenic trioxide (ATO)-induced cardiotoxicity in H9c2 cells by inhibiting MAPK pathways activation. Methods: H9c2 cardiac cells were exposed to 10 µM ATO for 24 h to induce cytotoxicity. The cells were pretreated with Sal A for 4 h before exposure to ATO. Cell viability was determined utilizing the MTT assay. The percentage of apoptosis was measured by a FITC-Annexin V/PI apoptosis kit for flow cytometry. Mitochondrial membrane potential (∆Ψm) was detected by JC-1. The intracellular ROS levels were measured using an Image-iTTM LIVE Green Reactive Oxygen Species Detection Kit. The apoptosis-related proteins and the MAPK signaling pathways proteins expression were quantified by Western blotting. Results: Sal A pretreatment increased cell viability, suppressed ATO-induced mitochondrial membrane depolarization, and significantly altered the apoptotic rate by enhancing endogenous antioxidative enzyme activity and ROS generation. Signal transduction studies indicated that Sal A suppressed the ATO-induced activation of the MAPK pathway. More importantly, JNK, ERK, and p38 inhibitors mimicked the cytoprotective activity of Sal A against ATO-induced injury in H9c2 cells by increasing cell viability, up-regulating Bcl-2 protein expression, and down-regulating both Bax and caspase-3 protein expression. Conclusion: Sal A decreases the ATO-induced apoptosis and necrosis of H9c2 cells, and the underlying mechanisms of this protective effect of Sal A may be connected with the MAPK pathways.

Red clover flavonoids protect against oxidative stress-induced cardiotoxicity in vivo and in vitro

Red clover flavonoids (RCF) which contain significant amounts of polyphenolic substances are known for their potential antioxidant properties. However, little is known about their effect on oxidative stress-induced myocardial injury. The objective of this study was to investigate the potential protective effects and mechanisms of RCF on isoproterenol (ISO)-induced myocardial injury in rats and on H2O2-induced apoptosis of H9c2 cardiomyocytes. An in vivo study revealed that RCF (200, 100 and 50 mg kg−1, i.g., respectively) daily for 15 days can prevent ISO-induced myocardial damage, including a decrease of serum cardiac enzymes and improvement in heart vacuolation. RCF also improved the free radical scavenging and antioxidant potential, suggesting one possible mechanism of RCF-induced cardio-protection is mediated by blocking the oxidative stress. An in vitro investigation demonstrated that RCF pretreatment increased cell viability, decreased levels of LDH leakage and PI-positive cells compared with the H2O2 group. Moreover, RCF pretreatment inhibited cell apoptosis, as evidenced by improved mitochondrial membrane potential disruption, decreased caspase-3 level, as well as increased Bcl-2/Bax ratio. Further mechanism investigation revealed that RCF prevented H9c2 cardiomyocytes injury and apoptosis induced by MAPK pathways. These results suggest that RCF exerted cardioprotective effects against myocardial injury by inhibiting oxidative stress, cardiac myocyte apoptosis, and modulating MAPK pathways, indicating that RCF might be a potential agent in the treatment of heart disease.

Protective effect of total saponins of Aralia elata (Miq) Seem on lipopolysaccharide-induced cardiac dysfunction via down-regulation of inflammatory signaling in mice

Aralia elata (Miq) Seem is widely used in folk medicine for treating various types of diseases, including diabetes, gastric ulcers, hepatitis and rheumatoid arthritis. The present study investigates the therapeutic effects and possible mechanisms of the total saponins of A. elata (Miq) Seem (TAS) against lipopolysaccharide (LPS)-induced septic cardiac dysfunction and inflammation in mice. Mice were intragastrically administrated with TAS (35, 70 and 140 mg kg−1) for one week before LPS challenge (10 mg kg−1, i.p.). Cardiac injury was evaluated 6 h after LPS induction. Six hours of LPS administration deteriorated cardiac function which was attenuated by TAS pretreatment. TAS attenuated LPS-induced the increase of LDH, CK, AST, and cTnI activities in mice. TAS also ameliorated the imbalance between iNOS and eNOS, as well as preventing NF-κB activation and the subsequent myocardial inflammatory responses in endotoxemic mice. TAS could significantly downregulate LPS-mediated NOX2 expression and ROS production, even though TAS had no effect on LPS-activated TLR-4. The effects of TAS were closely associated with PI3K/AKT and MAPK signaling pathways, as characterized by TAS-induced activation in phospho-Akt and inhibition in phospho-ERK1/2, phospho-JNK, and phospho-P38. Besides, TAS also extended the lifespan of the toxemic mice. These results showed that TAS significantly attenuated LPS-induced cardiac dysfunction and production of inflammatory mediators by inhibiting NF-κB activation, indicating TAS as a potential therapeutic agent for septic cardiac dysfunction.

Tournefolic acid B, derived from Clinopodium chinense (Benth.) Kuntze, protects against myocardial ischemia/reperfusion injury by inhibiting endoplasmic reticulum stress-regulated apoptosis via PI3K/AKT pathways

BACKGROUND Protection the heart from ischemia/reperfusion (I/R) injury is an area of intense research, as myocardial infarction is a major cause of mortality and morbidity all around the world. Tournefolic acid B (TAB) is a relative new compound derived from Clinopodium chinense (Benth.) Kuntze (Chinese name: Feng Lun Cai). This traditional Chinese herbal medicine has been used for its activities on anti-inflammatory, lowering blood glucose, antitumor and antiradiation. However, the pharmacological effects of TAB were rarely studied. PURPOSE Pathways involving phosphoinositide 3-kinase (PI3K) and protein kinase b (Akt) are crucial in regulating the ER stress and associated apoptosis in the process of I/R injury. In the present study, we aim to investigate the cardioprotective effects of tournefolic acid B (TAB) against myocardial I/R injury and explore the molecular mechanisms involved. STUDY DESIGN H9c2 cadiomyocyte were incubated with TAB for 24 h and then exposed to hypoxia/reoxygenation. Isolated rat hearts were subjected to global ischemia and reperfusion in the absence or presence of TAB. METHODS The possible mechanisms were investigated in vitro and ex vivo by multiple detection methods including JC-1 staining, ROS detection, activities of caspases detection, TUNEL staining, and Western-blot analysis. RESULTS We found that TAB significantly improved the hemodynamic parameters (LVeDP, LVSP, + dP/dtmax, - dP/dtmin, and HR) of isolated rat hearts, and depressed the cardiomyocyte apoptosis. Besides, TAB inhibited the oxidative stress by adjusting the activities of antioxidant enzymes (SOD, CAT, and GSH-Px). The I/R injury triggered the endoplasmic reticulum (ER) stress by activating the ER proteins, such as Grp78, ATF6, PERK, and eIf2α. which are all refrained by TAB. TAB also enhanced the phosphorylation of PI3K and AKT, inhibited the expression of CHOP and Caspase-12, reduced the phosphorylation of JNK, and increased Bcl-2/Bax ratio. CONCLUSION TAB protects against myocardial I/R injury by suppressing PI3K/AKT-mediated ER stress, oxidative stress, and apoptosis, revealing a promising therapeutic agent against ischemic cardiovascular diseases.