ABSTRACT
Aim To explore the regulatory effect and mechanism of Regulators of G-protein Signaling 6 (RGS6) in Ang H-induced hypertrophy. Methods RGS6 expression was up-and down-regulated respectively by AdRGS6 and AdshRGSó lentivirus. Each group was treated with Ang II /PBS. Cell size and changes of hypertrophic markers(ANP and BNP) were evaluated. Then ROS levels and the total protein and phosphorylated protein of E R K 1 / 2, p38, JNK1/2 in each group were detected. When the altered signaling was clarified, a reversal experiment of hypertrophic cardiomyocytes was conducted to further verify the signaling pathway. The RGS6 up-regulated cardiomyocytes of hypertrophy treated with ROS inhibitor (DPI) were experimental group. Results (Î) After stimulated with Ang II for 48 h, the size of AdRGS6-infected cell increased compared with AdGFP infection group. In addition, the mRNA levels of ANP and BNP also i n - creased. After stimulated with Ang II , the ROS levels and p - J N K l / 2 proteins of AdRGS6-infected cells all increased compared with AdGFP infection group. (2) After stimulated with Ang II for 48 h, the size of A d - shRGS6-infected cell decreased compared with AdshRNA infection group and the mRNA levels of ANP and BNP also decreased. The ROS levels and p - J N K l / 2 proteins of AdshRGS6-infected cell all decreased compared with AdshRNA infection group. (3) In the reversal experiments, compared with AdRGS6 + Ang 1 1 / DMSO group, the size of AdRGS6 + Ang H / D P I cardiomyocytes significantly decreased, and the downstream signaling of p - J N K l / 2 was improved. Conclusions RGS6 may be a key factor to cardiac hypertrophy. RGS6 aggravates Ang II -induced cardiomyocyte hypertrophy via activating R 0 S - K N K 1 / 2 signaling pathway.
ABSTRACT
Objective To investigate the effect of Hsp22 on phenylephrine-induced cardiomyocytes hypertrophy.Methods Primary rat myocardial cells were isolated and cultured in Department of Cardiology,the First Affiliated Hospital of Zhengzhou University.Cells were divided into four groups randomly:Control group,model group,treatment group with 1 μg/mL Hsp22,and treatment group with 10 μg/mL Hsp22.Phenylephrine stimuli was used to induce cardiomyocytes hypertrophy model.Cell viability was measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.Cardiomyocytes surface area was evaluated by α-actin immunofluorescence staining.Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the transcription level of hypertrophic markers.Reactive oxygen species level was detected by 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescent probe.Apoptosis was detected by TUNEL staining.Signal pathway protein expression was detected by Western blot.SPSS 13.0 was used for statistical analysis.Data were expressed as mean + standard deviation.All data were analyzed by one-way ANOVA between groups.Comparisons between two groups were performed using LSD-t test.A P＜0.05 was considered statistically significant.Results Different concentrations of Hsp22 had no effect on cardiomyocytes viability (F=6.622;P＞0.05).Phenylephrine stimulation significantly increased cardiomyocytes area (t=10.80;P＜0.05),increased the transcription level of hypertrophy markers atrial natriuretic peptide (t=37.72;P＜0.05),type B natriuretic peptide (t=16.85;P＜0.05),and myosin heavy chain beta (t=41.53;P＜0.05).Different concentrations of Hsp22 significantly reduced cardiomyocytes area (PE+ 1 μg/mL Hsp22 t=4.018;P＜0.05;PE+10 μg/mL Hsp22 t=10.80;P＜0.05),reduced the transcription level of hypertrophic markers atrial natriuretic peptide (PE+1 μg/mL Hsp22 t=27.12,P＜0.05;PE+10 μg/mL Hsp22 t=37.72,P＜0.05),type B natriuretic peptide (PE+1 μg/mL Hsp22 t=4.82,P＜0.05;PE+10 μg/mL Hsp22 t=12.74,P＜0.05),and myosin heavy chain beta (PE+1 μg/mL Hsp22 t=23.68,P＜0.05;PE+10 μg/mL Hsp22 t=30.54,P＜0.05).Westem blot showed that Hsp22 increased the activation of AMP-activated protein kinase α (PE+1 μg/mL Hsp22 t=5.89,P＜0.05;PE+10 μg/mL Hsp22 t=5.88,P＜0.05),reduced mTOR phosphorylation level (PE+1 μg/mL Hsp22 t=16.80,P＜0.05;PE+10.μg/mL Hsp22 t=20.46,P＜0.05).Conclusions Hsp22 inhibits cardiomyocytes hypertrophy by activating AMP-activated protein kinase α.Hsp22 may become a potential anti-hypertrophic drug.
ABSTRACT
AIM: To study the effects of κ-opioid receptor activation on the cardiac hypertrophy, cultured cardiomyocytes were to used study the inhibitory effects of U58,488H on cellular volume and norepinephrine(NE)-induced hypertrophy in the presence or absence of norbinaltorphimine(nor-BNI). METHODS: The protein content was assayed with Lowry's method. The cardiomyocytes' volumes was measured by an eyepiece graticule of inverted microscope. The contracting frequency of cultured myocytes was counted by the inverted microscope. RESULTS: A κ-opioid receptor agonist U50, 488H at (0.1 ∼ 10 μmol·L-1) inhibited the protein content of cultured myocardial cells in normal serum medium in a dose-dependent manner. The inhibitory effects of U50,488H were completely blocked by pretreatment with nor-BNI, a specific κ-opioid receptor antagonist at 1 μmol·L-1. U50,488H (0.1 ∼ 10 μmol·L-1) also inhibited NE-induced cellular hypertrophy in low serum medium, which also were abolished by nor-BNI (1 μmol· L-1). CONCLUSIONS: U50,488H inhibited NE-induced hypertrophy. The inhibitory effects of U50,488H are involved in mediating the action of NE-induced cardiac hypertrophy.
ABSTRACT
AIM : To investigate the effects of Ca 2+ /CaM dependent calcineurin(CaN) signaling pathway on cardiomyocytes hypertrophy of rat induced by neuropeptide Y(NPY). METHODS : Cardiomyocytes of neonatal Wistar rats were cultured with NPY of various concentrations (10,100 nmol?L -1 ). Cyclosporine A (CsA) was used to inhibit the activity of CaN. The methods of 3H Leu incorporation was used to assess protein synthesis rate in cardiomyocytes. Western blot and histochemistry were used to measure CaN protein expression and CaN activity in cardiomyocytes. RESULTS : 3 H Leu incorporation of cardiomyocytes were increased significantly by 100 nmol?L -1 NPY ( P
ABSTRACT
AIM To study the effects of ?-opioid receptor activation on the cardiac hypertrophy, cultured cardiomyocytes were to used study the inhibitory effects of U58,488H on cellular volume and norepinephrine(NE)-induced hypertrophy in the presence or absence of norbinaltorphimine(nor-BNI). METHODS The protein content was assayed with Lowry's method. The cardiomyocytes'volumes was measured by an eyepiece graticule of inverted microscope. The contracting frequency of cultured myocytes was counted by the inverted microscope. RESULTS A ?-opioid receptor agonist U50,488H at (0.1～10 ?mol?L -1 ) inhibited the protein content of cultured myocardial cells in normal serum medium in a dose-dependent manner. The inhibitory effects of U50,488H were completely blocked by pretreatment with nor-BNI, a specific ?-opioid receptor antagonist at 1 ?mol?L -1 . U50,488H (0.1～10 ?mol?L -1 ) also inhibited NE-induced cellular hypertrophy in low serum medium, which also were abolished by nor-BNI(1 ?mol?L -1 ). CONCLUSIONS U50,488H inhibited NE-induced hypertrophy. The inhibitory effects of U50,488H are involved in mediating the action of NE-induced cardiac hypertrophy.
ABSTRACT
Aim To investigate the effect of iptakalim on neonatal cardiomyocytes hypertrophy induced by isoprenaline(ISO).Methods Hypertrophy in neonatal rat cardiac myocytes was established via culture with ISO.Total protein content was measured by Lowrys method.The fluorescence intensity of intracellular Ca2+ was detected respectively with Fluo-3/AM loading by the laser confocal microscopy.Results ① 1?10-5mol?L-1 ISO can activated ?-AR completely;② the total protein of cardiomyocytes and intracellular i was markedly decreased by treatment with IPT and represented a dose-dependent manner.Conclusion IPT could inhibit the increase of protein content of cardiomyocytes induced by ISO,which may be contributed to the decease of intracellular Ca2+ concentration.