Hydrogen sulfide inhibits doxorubicin-induced inflammation and cytotoxicity in rat cardiomyocytes by modulating activation of NF-κB pathway

AIM：To investigate whether hydrogen sulfide (H2S) attenuates doxorubicin (DOX)-induced inflammation and cytotoxicity in rat cardiomyocytes (H9c2 cells) by modulating nuclear factor κB (NF-κB) pathway. METHODS：The expression of NF-κB p65 was measured by western blotting. The secretion levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor α (TNF-α) were tested by enzyme-linked immunosorbent assay (ELISA). Cell viability was detected by Cell Counting Kit-8 (CCK-8) assay. Hoechst 33258 nuclear staining was used to detect the morphological changes and number of apoptotic cells. RESULTS：Treatment of H9c2 cells with 5 μmol/L DOX significantly up-regulated the expression level of phosphorylated NF-κB p65 (p-p65), and induced inflammation and cytotoxicity, as evidenced by increases in secretion levels of IL-1β, IL-6 and TNF-α and number of apoptotic cells as well as a decrease in cell viability. Pretreatment of H9c2 cells with 400 μmol/L NaHS (a donor of H2S) for 30 min markedly depressed the up-regulation of p-p65 expression induced by DOX. In addition, NaHS pretreatment also reduced DOX-induced inflammatory response and injury, leading to decreases in IL-1β, IL-6 and TNF-α secretion and number of apoptotic cells as well as an increase in cell viability. Similar to the effect of NaHS, pretreatment with 100 μmol/L pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, also blocked DOX-induced cardiac inflammation and cytotoxicity. Co-administration of IL-1 receptor antagonist (IL-1Ra) and DOX reduced DOX-induced activation of NF-κB and cytotoxicity in H9c2 cells. CONCLUSION：During the DOX-induced cardiomyocyte inflammation, there is positive interaction between NF-κB pathway and IL-1β. H2S may protect cardiomyocytes against DOX-induced inflammatory response and cytotoxicity by inhibiting NF-κB pathway.     

NRF2 attenuates oxidative stress and lysosomal dysfunction in doxorubicin-induced H9C2 cells

AIM:To study the effect of nuclear factor E2-related factor 2 (NRF2) on oxidative stress injury and lysosomal dysfunction in doxorubicin (DOX)-induced rat myocardial H9C2 cells. METHODS:The H9C2 cells were treated with DOX. The expression of NRF2 at mRNA and protein levels was determined by real-time PCR and Western blot. The H9C2 cells stably over-expressing NRF2 were established by lentiviral infection. Real-time PCR and Western blot were used to identify the efficiency of over-expression. After DOX treatment, the cell viability was measured by CCK-8 assay, the activity of lactate dehydrogenase (LDH), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), and the content of malondialdehyde (MDA) in the cell supernatant were detected. FITC-dextran was used to analyze lysosomal pH, and the protein expression of lysosomal-associated membrane protein 1 (LAMP1) and cathepsin B was determined by Western blot.RESULTS:The expression of NRF2 at mRNA and protein levels in DOX-treated H9C2 cells was significantly decreased (P<0.05). Over-expression of NRF2 significantly up-regulated the mRNA and protein expression of NRF2 in DOX-treated H9C2 cells (P<0.05). After DOX treatment, the cell viability was decreased, and LDH activity was increased. The activity of SOD, GSH-Px and CAT was decreased, and the content of MDA was increased (P<0.05). The lysosomal pH was increased, and the protein expression of LAMP1 and cathepsin B decreased (P<0.05). Over-expression of NRF2 increased the cell viability, decreased LDH activity, increased the activity of SOD, GSH-Px and CAT, and decreased the content of MDA in cell supernatant (P<0.05). Over-expression of NRF2 also decreased the lysosomal pH, and increased the protein expression of LAMP1 and cathepsin B (P<0.05). CONCLUSION:DOX inhibits the expression of NRF2 in the myocardial H9C2 cells. Over-expression of NRF2 attenuates oxidative stress and lysosomal dysfunction in the H9C2 cells induced by DOX.     

Scutellarin affects LPS-induced oxidative stress and apoptosis of glomerular epithelial cells by up-regulating miR-7-5p

AIM To investigate the effect of scutellarin （SCU） on oxidative stress and apoptosis induced by lipopolysaccharide （LPS） in human glomerular epithelial cells and its mechanism. METHODS Human glomerular epithelial cells were cultured in vitro, and were treated with LPS （1.0 mg/L） to establish a cell injury model. The cells were divided into normal control （NC） group, LPS group, NC+SCU group, LPS+SCU group, LPS+miR-NC group, LPS+microRNA-7-5p （miR-7-5p） group, LPS+SCU+anti-miR-NC group and LPS+SCU+anti-miR-7-5p group. Cell viability was detected by CCK-8 assay. Apoptosis was detected by flow cytometry. The intracellular malondialdehyde （MDA） content and superoxide dismutase （SOD） activity, and lactate dehydrogenase （LDH） activity in the cell culture supernatant were determined by kit. RT-qPCR was used to detect the expression level of miR-7-5p. RESULTS Compared with NC group, the cell viability, miR-7-5p expression and SOD activity in LPS group were significantly reduced, and the apoptotic rate, MDA content and LDH activity were significantly increased （P<0.05）. Compared with LPS group, the cell viability, miR-7-5p expression and SOD activity in LPS+SCU group were significantly increased, and the apoptotic rate, MDA content and LDH activity were significantly reduced （P<0.05）. Compared with LPS+miR-NC group, the cell viability and SOD activity in LPS+miR-7-5p group were significantly increased, and the apoptotic rate, MDA content and LDH activity were significantly reduced （P<0.05）. Compared with LPS+SCU+anti-miR-NC group, the cell viability and SOD activity in LPS+SCU+anti-miR-7-5p group were significantly reduced, and the apoptotic rate, MDA content and LDH activity were significantly increased （P<0.05）. CONCLUSION Scutellarin inhibits LPS-induced oxidative stress damage and apoptosis in glomerular epithelial cells via up-regulating miR-7-5p expression.     

Mangiferin attenuates hypoxia/reoxygenation-induced injury of human myocardial cells

AIM To investigate the effect of mangiferin on hypoxia/reoxygenation (H/R)-induced injury of human myocardial cells and its mechanism. METHODS Human myocardial AC16 cells were divided into normal group, H/R group and H/R + mangiferin (50, 100 and 200 μmol/L) treatment groups. The mRNA and protein expression levels of Kelch-like epichlorohydrin-associated protein-1 (Keap-1), Bax, Bcl-2, caspase-3, caspase-9 and superoxide dismutase 2 (SOD2) were detected by RT-qPCR and Western blot, respectively. The protein expression of nuclear factor E2-related factor 2 (Nrf-2) in nucleus was determined by Western blot. The expression of microRNA-432-3p (miR-432-3p) was detected by RT-qPCR. The generation of reactive oxygen speciess (ROS) in the cells was measured by DCFH-DA probing. The cell viability was measured by CCK-8 assay. Apoptosis was analyzed by flow cytometry. RESULTS No significant difference in the expression of miR-432-3p and Keap-1 between normal group and H/R group was observed. Compared with normal group, the nuclear translocation of Nrf-2, the ROS level, and the mRNA and protein expression of Bax, caspase-3 and caspase-9 were significantly increased in H/R group （P<0.05）. The mRNA and protein expression of SOD2 and Bcl-2, and the cell viability significantly decreased in H/R group compared with normal group, while the apoptosis was increased significantly （P<0.05）. Treatment with mangiferin resulted in an increase in the miR-432-3p expression and a decrease in the ROS level, and the expression of Keap-1, Bax, caspase-3 and caspase-9 was also inhibited as compared with H/R group （P<0.05）. The Nrf-2 nuclear translocation, and the protein levels of SOD2 and Bcl-2 in mangiferin treatment groups were significantly increased as compared with H/R group （P<0.05）. The cell viability was increased significantly, and the apoptosis was decreased significantly in mangiferin treatment groups as compared with H/R group （P<0.05）. The effects of mangiferin in middle- and high-dose groups were better than those in low-dose group, and no significant difference between middle- and high-dose groups was found. CONCLUSION Mangiferin inhibits the decrease in myocardial cell viability and the apoptosis induced by H/R injury. The mechanism may be related to the up-regulation of Nrf-2 antioxidant stress effect via enhancing the expression of miR-432-3p.     

Berberine promotes anti-proliferative effects of doxorubicin in T24 bladder cancer cells by enhancing apoptosis

AIM: To observe the effect of berberine (Ber) on doxorubicin (DOX)-induced apoptosis in bladder cancer T24 cells. METHODS: The cells were exposed to DOX in the presence or absence of different concentrations of Ber. The viability of the cells was determined by CCK-8 assay. The apoptosis was measured by Hoechst 33258 staining and the protein levels of cleaved caspase-3, cleaved caspase-9, Bcl-2 and Bax were detected by Western blotting.RESULTS: Ber enhanced the inhibitory effect of DOX on the viability of T24 cells and promoted DOX-induced apoptosis in T24 cells. DOX increased the protein levels of cleaved caspase-3, cleaved caspase-9 and Bax, all of which were enhanced by treatment with Ber. In contrast, Ber exposure further decreased the expression of Bcl-2 in DOX-treated T24 cells.CONCLUSION: Ber enhances the anti-proliferative effects of DOX through promoting apoptosis in bladder cancer cells.     

Effects of PDCD5 on hypoxia/reoxygenation-induced autophagy and apoptosis of cardiomyocytes

AIM: To investigate the influence of programmed cell death 5 (PDCD5) on apoptosis and autophagy in the cardiomyocytes exposed to hypoxia/reoxygenation (H/R) and its potential mechanism.METHODS: H9c2 cells were exposed to H/R. PDCD5 was downregulated by RNA interference. The cell viability was measured by MTT assay. TUNEL assay was used to detect cell apoptosis. The mRNA and protein levels were determined by RT-qPCR and Western blot.RESULTS: The expression of PDCD5 was upregulated in the cardiomyocytes after H/R injury. Furthermore, H/R injury obviously reduced the cell viability and enhanced the apoptosis and autophagy of the cardiomyocytes. However, knockdown of PDCD5 increased the cell viability, and attenuated H/R-induced apoptosis, accompany with reduction of Bax and augment of Bcl-2 expression. Additionally, silencing PDCD5 markedly inhibited H/R-induced autophagy by regulating the expression of LC3-II/LC3-I and beclin-1. Moreover, downregulation of PDCD5 suppressed NF-κB signaling by redu-cing the protein level of p-P65.CONCLUSION: Silencing PDCD5 suppresses H/R-induced H9c2 cells apoptosis and autophagy by blocking NF-κB signaling pathway. The result indicates a new strategy for the prevention and treatment of myocardial I/R injury.     

Effects of endoplasmic reticulum stress induced by increased expression of calcium-sensing receptor in myocardial hypoxia/re-oxygenation injury

AIM: To observe the effects of endoplasmic reticulum stress induced by the increase in expression of calcium-sensing receptor in myocardial hypoxia/re-oxygenation injury. METHODS: The primarily neonatal rat ventricular cardiomyocytes were incubated for 4-5 d, then randomly divided into 5 groups: (1) sham control group; (2) hypoxia/re-oxygenation group; (3) H/Re+ NiCl2, CdCl2-reperfusion group; (4) H/Re+GdCl3, NiCl2, CdCl2-reperfusion group; (5) H/Re+caffeine,GdCl3, NiCl2, CdCl2-reperfusion group. The neonatal cells were in ischemia-mimetic solution for 3 h, and re-incubated cells in normal culture medium for 9 h to establish a model of H/Re. The activity of LDH was determined, the viability and apoptosis of cardiomyocytes were assayed by MTT, the expressions of CaSR and caspase-12 in each group were analyzed using Western blotting, and the concentration of intracellular calcium was measured by laser confocal scanning microscope. RESULTS: The apoptosis index, the activity of LDH, the concentration of intracellular calcium, and quantitative expression of CaSR and caspase-12 in H/Re and activator groups were significantly higher than those in control group, while the viability and apoptosis of cardiomyocytes were lower than those in control group. CONCLUSION: In myocardial hypoxia/re-oxygenation, CaSR induces endoplasmic reticulum stress by altering the intracellular calcium homeostasis. The induction of apoptosis may be due to the increase in the expreesions of caspase-12 and other proapoptotic proteins.     

miR-499 attenuates myocardial injury in rats by targeting PTEN

AIM:To investigate the effect of microRNA-499 (miR-499) on myocardial injury in rats and its mechanism. METHODS:The rat model of ischemia-reperfusion (I/R) injury was established and the myocardial cells were primarily cultured. The expression level of miR-499 was detected by RT-qPCR. After hydrogen peroxide stimulation, CCK-8 assay and LDH kit were used to detect the viability and LDH release of the cells transfected with miR-499 mimic and siR-PTEN. The targeting relationship between miR-499 and PTEN was predicted by TargetScan and confirmed by luciferase test. RT-qPCR and Western blot were used to detect the effect of miR-499 mimic and inhibitor on the mRNA and protein expression levels of PTEN. After miR-499 inhibitor and siR-PTEN were co-transfected into the cells, CCK-8 assay and LDH kit were used to detect the viability and LDH release of the myocardial cells induced by hydrogen peroxide. RESULTS:The expression level of miR-499 in the I/R rats was increased rapidly, and then was decreased gradually in a time-dependent manner (P<0.05). miR-499 mimic and siR-PTEN significantly promoted the viability and decreased the LDH release of cardiomyocytes induced by hydrogen peroxide (P<0.05). miR-499 and PTEN had a targeting relationship. The expression of PTEN was significantly down-regulated by miR-499 mimic, and up-regulated by miR-499 inhibitor (P<0.05). Transfection with siR-PTEN reversed the inhibitory effect of miR-499 inhibitor on the cells. CONCLUSION:miR-499 attenuates the myocardial injury in rats by targeting PTEN.     

Down-regulation of miR-153-3p attenuates H2O2-induced H9C2 cell injury by promoting Nrf2 expression

AIM To study the effect of microRNA-153-3p (miR-153-3p) knock-down on oxidative injury of H9C2 cells induced by H₂O₂ and its specific mechanism. METHODS The oxidative stress injury of H9C2 cell model was induced by H₂O₂, and then the cell viability and the expression of miR-153-3p were detected by MTT assay and RT-qPCR, respectively. The effects of miR-153-3p knock-down on the H9C2 cell injury under oxidative stress were studied by RNA interference technology. The targets of miR-153-3p were identified by Western blot and dual-luciferase reporter assay. RESULTS MTT assay showed that the viability of H9C2 cells was decreased with the increase in H₂O₂ concentration (P<0.05). The results of RT-qPCR showed that the expression of miR-153-3p was increased with the increase in H₂O₂ concentration (P<0.05). Knock-down of miR-153-3p increased the viability of H9C2 cells under oxidative stress, decreased the cell apoptosis and the content of malondialdehyde (MDA), and increased the activity of superoxide dismutase (SOD). The expression of nuclear factor E2-related factor 2（Nrf2） and antioxidant response element（ARE） activity were increased with the increase in H₂O₂ concentration (P<0.01). TargetScan analysis and dual-luciferase reporter assay showed that Nrf2 was one of the potential target genes of miR-153-3p. The results of Western blot further showed that over-expression of miR-153-3p inhibited the expression of Nrf2 (P<0.01), while down-regulation of miR-153-3p increased the expression of Nrf2 (P<0.01). Dual interference with Nrf2 and miR-153-3p significantly reduced H9C2 cell viability, promoted the apoptosis, increased MDA content, and decreased SOD activity in the presence of H₂O₂ (P<0.01). CONCLUSION Inhibition of miR-153-3p expression attenuates the injury of H9C2 cells induced by H₂O₂ through up-regulating Nrf2/ARE signaling pathway.     

miR-153 promotes LPS-induced myocardial H9C2 cell injury by targeting SORBS2

AIM: To study the effects of microRNA-153 (miR-153) on inflammatory factors, cell viability and apoptosis of embryonic rat H9C2 cardiomyocytes induced by lipopolysaccharide (LPS), and to explore its mechanism. METHODS: The injury model of H9C2 cells was established by LPS stimulation. The H9C2 cells were divided into anti-miR-Con group (transfected with anti-miR-Con), anti-miR-153 group (transfected with anti-miR-153), pcDNA group (transfected with pcDNA), pcDNA-SORBS2 group (transfected with pcDNA-SORBS2), anti-miR-153+si-Con group (co-transfected with anti-miR-153 and si-Con) and anti-miR-153+si-SORBS2 group (co-transfected with anti-miR-153 and si-SORBS2), and treated with LPS after transfection. The expression of miR-153 and SORBS2 mRNA in the cells was detected by RT-qPCR. The viability of H9C2 cells was measured by MTT assay. The protein expression of SORBS2 in the H9C2 cells was determined by Western blot. The contents of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were detected by ELISA. The apoptosis of the H9C2 cells was analyzed by flow cytometry. The targeting relationship between miR-153 and SORBS2 was verified by dual-luciferase reporter assay. RESULTS: The LPS-induced H9C2 cell injury model was successfully constructed. Compared with PBS group, the expression of miR-153 was significantly increased and the expression of SORBS2 was significantly decreased in the H9C2 cells treated with LPS. The inhibition of miR-153 and over-expression of SORBS2 decreased the contents of TNF-α and IL-6 and the level of apoptosis, but increased the cell viability. miR-153 inhibited the luciferase activity of the H9C2 cells containing wild-type SORBS2. Inhibition of SORBS2 reversibly inhi-bited the anti-inflammatory effects of miR-153 on LPS-induced H9C2 cells and increased the viability of the cells. CONCLUSION: miR-153 promotes the secretion of inflammatory factors, induces apoptosis, and inhibits the viability of H9C2 cells induced by LPS, thus enhancing the damage. Its mechanism may be related to targeting SORBS2, which will provide new targets for the treatment of myocardial injury.     

Regulatory effect of miR-214-5p on myocardial injury and immune response in ischemia-reperfusion rats by targeting PAK4

AIM: To investigate the effect of microRNA-214-5p (miR-214-5p) on myocardial injury and immune response in rats with ischemia-reperfusion (I/R) by targeting p21-activated protein kinase 4 (PAK4). METHODS: The rats were divided into sham group, I/R group, Ad-Scramble group, and Ad-miR-214 group (n=9). Adenovirus was injected into 6 different sites on the anterior wall of the left ventricle of the rats. Four days later, the I/R model was constructed by suturing the left anterior descending coronary artery. The expression level of miR-214 was detected by RT-qPCR. Myocardial injury was observed by HE staining. The levels of heart damage markers (CK-MB, Mb, and cTnI) and inflammatory factors (IL-6, IL-1β and TNF-α) were measured by ELISA. The rate of cardiomyocyte apoptosis was analyzed by flow cytometry. The content of MDA and the activity of SOD were detected by commercially available kits. Target genes were predicted by genetic software and verified by dual-luciferase reporter assay. The protein levels of caspase-3, caspase-9, Bcl-2, Bax, PAK4, p-Akt and p-mTOR were determined by Western blot. RESULTS: miR-214 was down-regulated in the cardiomyocytes of I/R rats (P<0.01). Over-expression of miR-214-5p attenuated myocardial injury in the I/R rats, down-regulated the expression of CK-MB, Mb and cTnI, decreased the apoptotic rate of cardiomyocytes, up-regulated the expression of Bcl-2, down-regulated Bax, caspase-3 and caspase-9 expression, increased SOD activity, and decreased the content of MDA, IL-6, IL-1β and TNF-α (P<0.01). The binding sites of miR-214-5p and PAK4 were pre-sent in the 3’-UTR, and over-expression of miR-214-5p up-regulated the protein levels of PAK4, p-Akt and p-mTOR (P<0.01). CONCLUSION: miR-214-5p over-expression attenuates myocardial injury in I/R rats by targeting PAK4, inhibits cardiomyocyte apoptosis, oxidative stress and inflammation, and activates the PI3K/Akt/mTOR pathway.     

Xinshuaikang inhibits myocardial autophagy and MAPK/ERK1/2 signaling pathway in rats with chronic heart failure

AIM:To explore the effect of Xinshuaikang on myocardial autophagy in the rats with chronic heart failure and its relationship with the MAPK/ERK1/2 signaling pathway. METHODS:The rats were divided into sham group, model group (rat model of chronic heart failure was established by ligation of anterior descending branch of left coronary artery), low-, middle-, and high-dose Xinshuaikang treatment (TL, TM and TH) groups and captopril group (treated with captopril as positive control), with 12 in each group. Doppler echocardiography was used to evaluate the cardiac function. The morphological changes of the myocardium were observed by HE staining. TUNEL staining was used to detect cardiomyocyte apoptosis. The expression of microtubule-associated protein 1 light chain 3-Ⅱ (LC3-Ⅱ) in the myocardium was detected by immunofluorescence labeling. The protein levels of p-ERK, p-p38 MAPK, LC3-Ⅱ, beclin-1 and p62 in the myocardium were determined by Western blot. RESULTS:Compared with sham group, left ventricular end-diastolic dia-meter (LVEDD) and left ventricular end-systolic diameter (LVESD) in model group were increased, while left ventricular posterior wall thickness at end-diastole (LVPWTd), left ventricular posterior wall thickness at end-systole (LVPWTs), left ventricular ejection fraction (LVEF), cardiac output (CO), left ventricular diastolic pressure (LVDP), left ventricular systolic pressure (LVSP) and maximum rate of rise/decrease of left ventricular pressure (+dp/dt_max/-dp/dt_max) were decreased (P<0.05). The myocardial cells were deformed and necrotic, and the myocardial fibers were broken, with inflammatory cell infiltration. The apoptotic rate, the positive rate of LC3-Ⅱ, and the protein levels of p-ERK, p-p38 MAPK, LC3-Ⅱ/LC3-I and beclin-1 were increased, and the protein expression of p62 was decreased (P<0.05). Compared with model group, the levels of LVEDD and LVESD were decreased, LVPWTd, LVPWTs, LVEF, CO, LVSP, LVDP, +dp/dt_max and -dp/dt_max were increased in Xinshuaikang groups and captopril group (P<0.05). The morphological changes of myocardial cells were gradually returned to normal, and inflammatory cell infiltration, the apoptotic rate and the positive rate of LC3-Ⅱ were decreased. The protein levels of p-ERK, p-p38 MAPK, LC3-Ⅱ/LC3-I and beclin-1 were decreased, and the protein expression of p62 was increased (P<0.05). CONCLUSION:Xinshuaikang inhibits myocardial auto-phagy to play a role of cardiac protection in the rats with chronic heart failure, and its mechanism may be related to inhibition of MAPK/ERK1/2 signaling pathway.     

Endogenous basic fibroblst growth factor is a protective factor against myocardial ischemia/reperfusion injury of rats

AIM: To observe the role of exogenous and endogenous basic fibroblst growth factor (bFGF) on myocardial ischemia/reperfusion(I/R) injury of rats.METHODS:bFGF and bFGF antiserum were applied to rat isolated I/R heart. Myocardial function, coronary effluent volume,protein and myoglobin content as well as LDH activity in coronary effluent fluid, myocardial calcium, MDA and ATP concentration as well as PKC, MAPK activity were measured. RESULTS:Compared with control, myocardial function in I/R group significantly decreased. Protein, myoglobin content and LDH activity in coronary effluent liquid as well as myocardial MDA and calcium content increased, while myocardial ATP concentration decreased(all P＜0.01). Compared with I/R group, ±LV dp/dt_max in bFGF group increased by 43% and 26%, respectively. LVEDP decreased by 40%. HRr/HRi and B/A augmented by 42% and 20%, respectively. Protein and myoglobin content as well as LDH activity lowered by 29%,30％ (all P＜0.01) and 33％ (P＜0.05) respectively. Myocardial MDA and calcium content decreased by 44% and 35%, respectively, while myocardial ATP level as well as PKC and MAPK activity increased by 34%,41％ and 10% (all P＜0.01), respectively. In bFGF antiserum group, ±LV dp/dt_max were 35% and 38% lower than those in I/R group. LVEDP increased by 93%. HRr/HRi and B/A decreased by 36% and 45%, respectively. Protein and myoglobin content as well as LDH activity augmented by 54%,96％ (all P＜0.01) and 34％ (P＜0.05) respectively. Myocardial MDA and calcium content increased by 24% and 50%, respectively, while myocardial ATP level as well as PKC and MAPK activity lowered by 28%,21％ and 8% (all P＜0.01), respectively. CONCLUSION:Endogenous bFGF is a protective factor against myocardial ischemia/reperfusion injury of rats.     

APPL1 reduces injury of H9c2 cardiomyocytes induced by LPS

AIM:To study the effect of APPL1 (adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1) on H9c2 cardiomyocyte injury induced by lipopolysaccharides (LPS). METHODS:The H9c2 cells were treated with LPS. RT-qPCR and Western blot were used to detect the expression of APPL1 in the H9c2 cells. The recombinant APPL1 lentiviral vector was used to transfect into the H9c2 cells. After LPS treatment, the over-expression efficiency was detected by RT-qPCR and Western blot. The viability was measured by MTT assay. The apoptosis was analyzed by flow cytometry. The protein level of activated caspase-3 in the H9c2 cells was determined by Western blot. The content of malonaldehyde (MDA) in the H9c2 cells and the level of lactate dehydrogenase (LDH) in the culture medium were detected. The activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the level of reative oxygen species (ROS) in the H9c2 cells were also examined. RESULTS:The expression of APPL1 at mRNA and protein levels in LPS-treated H9c2 cells was decreased significantly (P<0.05). Over-expression of APPL1 by transfection of recombinant lentiviral vector significantly increased the level of APPL1 at mRNA and protein levels in the H9c2 cells with LPS treatment (P<0.05). LPS treatment reduced the viability, but increased the apoptotic rate of the H9c2 cells, the protein level of activated caspase-3, the content of MDA and the level of LDH in the culture medium. The activity of SOD and GSH-Px was reduced, while the level of ROS was increased as compared with control group (P<0.05). Over-expression of APPL1 elevated the viability of H9c2 cells treated with LPS, and the apoptotic rate and the protein level of activated caspase-3 were decreased. The content of MDA and the level of LDH in the culture medium were reduced, the activity of SOD and GSH-Px was elevated, and the level of ROS was reduced as compared with the H9c2 cells treated with LPS alone (P<0.05). CONCLUSION:Over-expression of APPL1 reduces oxidative damage and apoptosis of the H9c2 cells induced by LPS.     

Tanshinone ⅡA attenuates doxorubicin-induced injury in H9c2 cardiomyocytes via AMPK-mediated autophagy

AIM: To investigate the effect of tanshinone ⅡA on doxorubicin-induced rat H9c2 cardiomyocyte injury. METHODS: The H9c2 cardiomyocytes were treated with tanshinone ⅡA and/or doxorubicin with or without AMPK inhibitor dorsomorphin. The cell viability was measured by CCK-8 assay, the LDH release was examined for evaluating the cell injury, autophagy was analyzed by immunofluorescence staining, and AMPK activation was determined by Western blot. RESULTS: Compared with control group, the viability of H9c2 cells was decreased, the release of LDH was increased, the autophagy degree was increased, and AMPK activation was inhibited after treatment with doxorubicin (P<0.05). Compared with doxorubicin group, the treatment with tanshinone ⅡA restored the cell viability, reduced the release of LDH, further increased autophagy degree, and activated AMPK in the H9c2 cells (P<0.05). AMPK inhibitor dorsomorphin attenuated the abilities of tanshinone ⅡA to restore the cell viability, reduce the release of LDH, and increase autophagy degree in the H9c2 cells (P<0.05). CONCLUSION: Tanshinone ⅡA attenuates doxorubicin-induced injury in H9c2 cardiomyocytes, and its mechanism might be related to AMPK-mediated autophagy, which provides experimental and theoretical basis for the clinical application of tanshinone ⅡA in the prevention and treatment of doxorubicin-induced cardiomyocyte injury.     

Adeno-associated virus type 9-mediated p65 silencing inhibits angiotensin II-induced apoptosis of H9c2 cells

AIM: To study the effect of p65 gene silencing by adeno-associated virus type 9 (AAV9)-mediated RNA interference on angiotensin Ⅱ (Ang Ⅱ; 10^-6 mol/L for 24 h)-induced apoptosis of rat ventricular H9c2 myocytes, and to elucidate the possible mechanism. METHODS: The H9c2 cells were transfected with rAAV9-eGFP and rAAV9-eGFP-NF-κB p65-siRNA at multiplicity of infection (MOI)=4×10⁶ vg/cell. eGFP expression in the cells was observed under an inverted fluorescence microscope, and the percentage of eGFP positive cells was determined by flow cytometry. The expression of p65 was determined by Western blot. CCK-8 assay was used to measured the viability of transfected H9c2 cells. The apoptosis of the cells transfected with the virus and with Ang Ⅱ stimulation was analyzed by flow cytometry. RESULTS: The cells began to exhibit eGFP expression on the 2nd day after transfection. The fluorescence intensity was increased over the time of transfection. eGFP expression reached the maximum on the 5th day, and the transfection efficiency was (52.7±1.9)% at this time point. Compared with blank control group, no significant effect of AAV9 on the viability of H9c2 cells was observed. In resting state, p65 in the H9c2 cells had a certain activity. After Ang Ⅱ stimulation, the activity of p65 was obviously increased, while transfection of rAAV9-eGFP-NF-κB p65-siRNA effectively inhibited the expression of p65. The apoptosis of H9c2 cells in Ang Ⅱ stimulation group was significantly higher than that in blank control group, while transfection of rAAV9-eGFP-NF-κB p65-siRNA effectively inhibited apoptosis of H9c2 cells. CONCLUSION: Transfection of rAAV9-eGFP-NF-κB p65-siRNA effectively inhibits the expression of p65 gene of NF-κB pathway in the H9c2 cells without causing cell growth inhibition, and reduces the apoptosis induced by Ang Ⅱ.     

CaMKII aggravates hypoxia/reoxygenation injury in H9c2 cells by activating apoptosis

AIM: To investigate the effect of Ca²⁺/calmodulin-dependent protein kinase Ⅱ (CaMKⅡ) on hypoxia/reoxygenation (H/R) injury in H9c2 cells. METHODS: H9c2 cells were randomized into 4 groups:control group, KN-93 (an inhibitor of CaMKⅡ; 1 μmol/L) treatment group, H/R group and H/R+KN-93 (1 μmol/L) treatment group. The cells in KN-93 group and KN-93+H/R group were pretreated with KN-93 for 2 h before the other treatment was performed. The viability of H9c2 cells in each group was measured by CCK-8 assay. Lactate dehydrogenase (LDH) activity in the culture medium was detected. The protein levels of phosphorylated CaMKⅡ (p-CaMKⅡ), phosphorylated phospholamban (p-PLN) and cleaved caspase-3 were determined by Western blot. The apoptosis was analyzed by TUNEL staining and the flow cytometry. RESULTS: No significant difference of all indexes tested between control group and KN-93 group was observed. H/R treatment significantly reduced the cell viability, and increased the activity of LDH (P<0.01), the protein levels of p-CaMKⅡ, p-PLN and cleaved caspase-3 (P<0.05), and the apoptotic rate (P<0.01). KN-93 (1 μmol/L) significantly increased the cell viability, and decreased the activity of LDH (P<0.01), the protein levels of p-CaMKⅡ, p-PLN and cleaved caspase-3 (P<0.05), and the apoptotic rate (P<0.01). CONCLUSION: CaMKⅡ aggravates hypoxia/reoxygenation injury in the H9c2 cells by activating apoptosis.     

Role of aloperine on ischemia-reperfusion-induced injury and inflammatory response in H9c2 cardiomyocytes

AIM: To explore the role of aloperine in ischemia-reperfusion (I/R)-induced H9c2 cardiomyocyte injury and inflammation.METHODS: The H9c2 cardiomyocytes were cultured under hypoxia and re-oxygenation conditions to simulate ischemia-reperfusion (SI/R) injury. After treatment with aloperine at various doses, the cell viability was measured by MTT assay. The cell apoptosis was analyzed by flow cytometry. Simultaneously, the levels of lactate dehydrogenase (LDH), malonaldehyde (MDA) and caspase-3 activity were detected by the commercial kits. The levels of inflammatory cytokines were also detected by ELISA. Moreover, the effects of aloperine on the activation of PI3K/AKT signaling pathway were determined by Western blot.RESULTS: Pre-treatment with aloperine remarkably abated the inhibitory effect of SI/R on H9c2 cell viability, and decreased the elevations of LDH and MDA triggered by SI/R (P<0.05). Pre-treatment with aloperine dramatically suppressed the cell apoptosis induced by SI/R treatment (P<0.05), concomitant with the decrease in caspase-3 activity and increase in Bcl-2/Bax ratio (P<0.05). In contrast to SI/R group, aloperine treatment notably restrained the concentrations of pro-inflammatory cytokines, including interleukin-6, tumor necrosis factor-α and interleukin-1β (P<0.05). Furthermore, aloperine remarkably increased the protein levels of p-PI3K and p-AKT. While blocking the PI3K/AKT pathway with its specific inhibitor LY294002, the viability-promoting, anti-apoptotic and anti-inflammatory effects of aloperine on the H9c2 cells were obviously attenuated (P<0.05).CONCLUSION: Alope-rine protects against cardiomyocytes from I/R injury and inhibits inflammatory responses by activating the PI3K/AKT signaling pathway, implying a potential benefic role of aloperine against myocardial I/R injury.     

Effects of PTEN on apoptosis,oxidative damage and immune inflammatory factors in myocardial H9c2 cells with anoxia/reoxygenation

AIM: To investigate the effects of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) on the apoptosis, oxidative damage and immune inflammatory factors in myocardial H9c2 cells with anoxia/reoxygenation (A/R). METHODS: The H9c2 cells were used to establish a model of A/R. The H9c2 cells were transfected with PTEN small interfering RNA (siRNA) and negative control. After A/R, the expression of PTEN at mRNA and protein levels was determined by RT-PCR and Western blot, respectively. The cell viability was measured by MTT assay. The apoptosis was analyzed by flow cytometry. Xanthine oxidase method was used to determine superoxide dismutase (SOD) activity. The content of malondialdehyde (MDA) was detected by thiobarbituric acid method. The lactate dehydrogenase (LDH) activity in the supernatant was evaluated by 4-dinitrophenylhydrazine method. The levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6 in culture supernatant were examined by ELISA. The protein levels of cleaved caspase-3, Bax and FasL in the cells were determined by Western blot. RESULTS: After A/R, the expression of PTEN at mRNA and protein levels was significantly increased in the H9c2 cells (P<0.05). The mRNA and protein levels of PTEN were decreased significantly after transfection with PTEN siRNA (P<0.05). The viability of H9c2 cells was decreased after A/R, while the apoptotic rate was increased. The protein levels of cleaved caspase-3, Bax and FasL were increased in the cells. The MDA level was elevated, the activity of SOD was decreased, and the levels of LDH, TNF-α, IL-1β and IL-6 in the culture supernatant were increased (P<0.05). Down-regulation of PTEN partly antagonized the effects of A/R on the viability, apoptotic rate, MDA content, SOD activity, and the levels of LDH, TNF-α, IL-1β and IL-6 in culture supernatant. CONCLUSION: Down-regulation of PTEN attenuates oxidative damage induced by A/R, reduces apoptosis and secretion levels of TNF-α, IL-1β and IL-6 in the H9c2 cells.