Effects of angiotensin Ⅱ on protein kinase Cε and Cα expression in hepatic stellate cells / 中国医师杂志

Objective To investigate the effect of angiotensin Ⅱ on protein kinase Cε (PKCε) and protein kinase Cα (PKCα) expression in hepatic stellate cells.Methods Hepatic stellate cell (HSC)-T6 cells were treated with different concentrations of angiotensin Ⅱ and the proliferation of HSC-T6 cells was detected by methyl thiazolyl tetrazolium (MTT) assay.The expression of PKCε and PKCα was detected by immunofluorescence staining.PKCε and PKCα mRNA levels was detected by real time polymerase chain reaction (PCR).Results Angiotensin Ⅱ concentrated the proliferation of HSC-T6 cells and the level of hydroxyproline (F =25.321,13.283,P ＜ 0.001) and showed a dose-dependent effect.With the increase of angiotensin Ⅱ concentration,PKCε significantly increased and translocated in the cell membrane;PKCα increased significantly,especially in transplanted membrane and cytoplasm (F =21.387,19.431,P ＜0.01),and showed obvious dose effect.Meanwhile,Angiotensin Ⅱ increased the expression of PKCε and PKCα,and induced cell proliferation by up-regulating PKCε and PKCα mRNA levels (F =13.279,15.174,P ＜ 0.05).Conclusions Angiotensin Ⅱ can up-regulate the expression of collagen in hepatic stellate cells in a dose-dependent manner,increase the expression of protein kinase Cε and Cα,and promote the proliferation of hepatic stellate cells.

Atorvastatin Attenuates Myocardial Hypertrophy Induced by Chronic Intermittent Hypoxia In Vitro Partly through miR-31/PKCε Pathway / 华中科技大学学报（医学）（英德文版）

Atorvastatin is proven to ameliorate cardiac hypertrophy induced by chronic intermittent hypoxia (CIH).However,little is known about the mechanism by which atorvastatin modulates CIH-induced cardiac hypertrophy,and whether specific hypertrophyrelated microRNAs are involved in the modulation.MiR-31 plays key roles in the development of cardiac hypertrophy induced by ischemia/hypoxia.This study examined whether miR-31 was involved in the protective role of atorvastatin against CIH-induced myocardial hypertrophy.H9c2 cells were subjected to 8-h intermittent hypoxia per day in the presence or absence of atorvastatin for 5 days.The size of cardiomyocytes,and the expression of caspase 3 and miR-31 were determined by Western blotting and RT-PCR,respectively.MiR-31 mimic or Ro 31-8220,a specific inhibitor of protein kinase C epsilon (PKCε),was used to determine the role of miR-31 in the anti-hypertrophic effect of atorvastatin on cardiomyocytes.PKCε in the cardiomyocytes with miR-31 upregulation or downregulation was detected using RT-PCR and Western blotting.The results showed that CIH induced obvious enlargement of cardiomyocytes,which was paralleled with increased atrial natriuretic peptide (ANP),brain natriuretic peptide (BNP),and slow/beta cardiac myosin heavy-chain (MYH7) mRNA levels.All these changes were reversed by the treatment with atorvastatin.Meanwhile,miR-31 was increased by CIH in vitro.Of note,the atorvastatin pretreatment significantly increased the mRNA and protein expression of PKCε and decreased that of miR-31.Moreover,overexpression of miR-31 abolished the anti-hypertrophic effect of atorvastatin on cardiomyocytes.Upregulation and downregulation of miR-31 respectively decreased and increased the mRNA and protein expression of PKCε.These results suggest that atorvastatin provides the cardioprotective effects against CIH probably via up-regulating PKCε and down-regulating miR-31.

Atorvastatin Attenuates Myocardial Hypertrophy Induced by Chronic Intermittent Hypoxia In Vitro Partly through miR-31/PKCε Pathway / 华中科技大学学报（医学）（英德文版）

Atorvastatin is proven to ameliorate cardiac hypertrophy induced by chronic intermittent hypoxia (CIH).However,little is known about the mechanism by which atorvastatin modulates CIH-induced cardiac hypertrophy,and whether specific hypertrophyrelated microRNAs are involved in the modulation.MiR-31 plays key roles in the development of cardiac hypertrophy induced by ischemia/hypoxia.This study examined whether miR-31 was involved in the protective role of atorvastatin against CIH-induced myocardial hypertrophy.H9c2 cells were subjected to 8-h intermittent hypoxia per day in the presence or absence of atorvastatin for 5 days.The size of cardiomyocytes,and the expression of caspase 3 and miR-31 were determined by Western blotting and RT-PCR,respectively.MiR-31 mimic or Ro 31-8220,a specific inhibitor of protein kinase C epsilon (PKCε),was used to determine the role of miR-31 in the anti-hypertrophic effect of atorvastatin on cardiomyocytes.PKCε in the cardiomyocytes with miR-31 upregulation or downregulation was detected using RT-PCR and Western blotting.The results showed that CIH induced obvious enlargement of cardiomyocytes,which was paralleled with increased atrial natriuretic peptide (ANP),brain natriuretic peptide (BNP),and slow/beta cardiac myosin heavy-chain (MYH7) mRNA levels.All these changes were reversed by the treatment with atorvastatin.Meanwhile,miR-31 was increased by CIH in vitro.Of note,the atorvastatin pretreatment significantly increased the mRNA and protein expression of PKCε and decreased that of miR-31.Moreover,overexpression of miR-31 abolished the anti-hypertrophic effect of atorvastatin on cardiomyocytes.Upregulation and downregulation of miR-31 respectively decreased and increased the mRNA and protein expression of PKCε.These results suggest that atorvastatin provides the cardioprotective effects against CIH probably via up-regulating PKCε and down-regulating miR-31.

Role of mitochondrial ATP-sensitive potassium channel in sevoflurane preconditioning-induced delayed cardioprotection against ischemia-reperfusion injury in isolated rat hearts / 中华麻醉学杂志

Objective To evaluate the role of the mitochondrial ATP-sensitive potassium (mito-KATP)channel in sevoflurane preconditioning-induced delayed cardioprotection against ischemia-reperfusion (I/R) injury in isolated rat hearts.Methods Seventy-two adult male Sprague-Dawley rats were randomly divided into 6 groups (n =12 each):control group (group CON),I/R group,sevoflurane control group (group SEVO),sevoflurane preconditioning group (group SWO P),5-hydroxydeconoate (5-HD) + sevoflurane preconditioning group (group 5-HD+ SWOP) and 5-HD control group (group 5-HD).The rats were exposed to 33％ pure oxygen for 1 h in groups CON and I/R.The rats were exposed to 2.5％ sevoflurane for 1 h in groups SEVO and SWOP.5-HD (a mito-KATP channel inhibitor) 10 mg/kg was injected intraperitoneally 30 min before sevoflurane preconditioning in group 5-HD + SWOP.5-HD 10 mg/kg was injected intraperitoneally in group 5-HD.The hearts were immediately removed and perfused in a Langendorff apparatus.The hearts were made globally ischemic for 30 min followed by 120 min reperfusion in groups I/R,SWOP,5-HD + SWOP and 5-HD.The expression of phosphorylated protein kinase C-epsilon (p-PKC-ε) and caspase-8 was measured by Western blot immediately before ischemia (T0) and at 120 min of reperfusion (T1).The myocardial infarct volume was measured by TTC staining.Results Compared with group CON,the myocardial infarct volume was significantly increased at T1 in groups I/R,SWOP,5-HD +SWOP and 5-HD,p-PKC-ε expression was up-regulated at T0 in groups SEVO and SWOP and at T1 in groups I/R,SWOP,5-HD + SWOP and 5-HD,and caspase-8 expression was down-regulated at T1 in group SEVO (P ＜0.05).Compared with group I/R,the myocardial infarct volume was significantly decreased at T1 in groups SWOP and 5-HD + SWOP,p-PKC-ε expression was up-regulated at T0 in groups SEVO and SWOP,and caspase-8 expression was down-regulated at T1 in group SWOP (P ＜ 0.05).Compared with group SWOP,the myocardial infarct volume was significantly increased,p-PKC-ε expression was down-regulated at T0,and caspase-8 expression was up-regulated at T1 in group 5-HD + SWOP (P ＜ 0.05).Conclusion The mito-KATP channel is involved in sevoflurane preconditioning-induced delayed cardioprotection against I/R injury in isolated rat hearts through upregulation of p-PKC-ε expression before ischemia and inhibition of cell apoptosis during reperfusion.

Inhibition of PKC Epsilon Attenuates Cigarette Smoke Extract-Induced Apoptosis in Human Lung Fibroblasts (MRC-5 Cells) / 결핵및호흡기질환

BACKGROUND: It is known that cigarette smoke (CS) causes cell death. Apoptotic cell death is involved in the pathogenesis of CS-related lung diseases. Some members of the protein kinase C (PKC) family have roles in cigarette smoke extract (CSE)-induced apoptosis. This study was conducted to investigate the role of PKC epsilon in CSE-induced apoptosis in human lung fibroblast cell line, MRC-5. METHODS: Lactate dehydrogenase release was measured using a cytotoxicity detection kit. The MTT assay was used to measure cell viability. Western immunoblot, Hoechst 33342 staining and flow cytometry were used to demonstrate the effect of PKCepsilon. Caspase-3 and caspase-8 activities were determined using a colorimetric assay. To examine PKCepsilon activation, Western blotting was performed using both fractions of membrane and cytosol. RESULTS: We showed that CSE activated PKCepsilon by demonstrating increased expression of PKCepsilon in the plasma membrane fraction. Pre-treatment of PKCepsilon peptide inhibitor attenuated CSE-induced apoptotic cell death, as demonstrated by the MTT assay (13.03% of control, 85.66% of CSE-treatment, and 53.73% of PKCepsilon peptide inhibitor-pre-treatment, respectively), Hoechst 33342 staining, and flow cytometry (85.64% of CSE-treatment, 53.73% of PKCepsilon peptide inhibitor-pre-treatment). Pre-treatment of PKCepsilon peptide inhibitor reduced caspase-3 expression and attenuated caspase-3, caspase-8 activity compared with CSE treatment alone. CONCLUSION: PKCepsilon seem to have pro-apoptotic function and exerts its function through the extrinsic apoptotic pathway in CSE-exposed MRC-5 cells. This study suggests that PKCepsilon inhibition may be a therapeutic strategy in CS-related lung disease such as chronic obstructive pulmonary disease.

Protection of Cardiomyocytes from Acute Ischemic Injury by Protein Kinase Cepsilon Expression

BACKGROUND AND OBJECTIVES: Ischemic injury is the most common and important cause of myocardial damage. Over past decades, a number of studies have identified a protective mechanism known as ischemic preconditioning, which can block or delay cell death from ischemic injury. Protein kinase C (PKC), especially theepsilonisoform has been proposed as a key factor in the signaling pathway of ischemic preconditioning. However, whether PKCepsilon expression in cardiomyocytes can offer such protection from acute ischemia has not been explored. MATERIALS AND METHODS: To demonstrate a direct effect of PKCepsilon expression, a lentiviral vector system was established. Using the lentiviral vector, PKCepsilon was introduced to neonatal rat ventricular myocytes (NRVM) cultured under ischemic conditions, and also to adult rat myocardium subject to left coronary artery ligation. RESULTS: Compared to control, PKCepsilon expression in cultured NRVM under ischemia resulted in preserved cell density and morphology, and a reduction in cell death (77.6+/-12.8% vs 58.1+/-7.2%, p<0.05). In adult rats, the infarcted area after coronary artery ligation was markedly reduced in myocardium injected with PKCepsilon vector compared to control (11.4+/-5.3% vs 20.5+/-11.3%, p<0.01). CONCLUSION: These results provide direct evidence that PKCepsilon is a central player in protection against cell death from acute ischemia.