白藜芦醇通过调节 SIRT1/AMPK 信号通路保护氧-葡萄糖剥夺大鼠皮质神经元

目的：探讨白藜芦醇对单次和双次氧-葡萄糖剥夺(oxygen-glucose deprivation, OGD)原代皮质神经元沉默信息调节因子1(silent information regulator 1, SIRT1)、AMP 活化的蛋白激酶(AMP-activated protein kinase, AMPK)活性和 ATP 含量的影响及其可能的神经保护机制。方法皮质神经元取自18 d Wistar 大鼠胚胎,原代培养成功后通过2次OGD 制作体外反复缺血模型。采用台盼蓝染色法检测细胞存活率,蛋白质印迹法检测 SIRT1和磷酸化 AMPK 表达,去乙酰化酶荧光检测法检测 SIRT1活性,生物发光测定法检测 ATP 含量。结果与对照组比较,白藜芦醇(0．5μmol/L)预处理能显著增高单次和双次 OGD 后存活率(P 均<0．001)、ATP 含量(P 均=0．004)、SIRT1活性(单次：P =0．001;双次：P =0．002)以及 SIRT1(单次：P =0．029;双次：P =0．023)和磷酸化 AMPK (P 均=0．001)表达水平。结论白藜芦醇对单次和双次 OGD 皮质神经元均具有神经保护作用,其机制可能与上调 SIRT1/AMPK 通路和降低能量需求有关。     

五味子乙素通过半胱天冬酶凋亡途径对抗高糖诱导的心肌细胞氧化应激损伤

目的 研究五味子乙素(Sch.B)是否可通过降低活性氧(ROS)的生成保护糖尿病状态下心肌细胞;是否通过抑制细胞凋亡减轻高糖诱导的心肌细胞损伤.方法 链脲佐菌素诱导Wistar大鼠制备1型糖尿病模型.口服药物Sch.B 4周后进行取材和检测.心肌细胞分为低糖组和高糖组,高糖+Sch.B组和高糖+氧自由基清除剂组.DHE...     

N-乙酰半胱氨酸通过AMPK/SIRT1途径抑制缺氧诱导的大鼠脑血管内皮细胞损伤

目的研究N-乙酰半胱氨酸(NAC)对缺氧诱导脑血管内皮细胞损伤的调节作用及分子机制。方法选择SD大鼠分离培养脑血管内皮细胞,分为常氧组、缺氧组、0. 5 NAC组(缺氧+0. 5 mol/L NAC)、1. 0 NAC组(缺氧+1. 0 mol/L NAC)、NAC+8-bAMP组(缺氧+1. 0 mol/L NAC+1. 0 mol/L 8-bAMP)。采用MTS法检测细胞增殖活力,采用TUNEL染色检测凋亡率,采用试剂盒检测氧化应激指标,采用Western blot检测凋亡基因、AMPK/SIRT1通路分子的表达量。结果缺氧组细胞OD490值、T-AOC含量及B淋巴细胞瘤2(Bcl-2)、p-AMP活化蛋白激酶(pAMPK)、去乙酰化酶Sirtuin1(SIRT1)表达量均明显低于常氧组;缺氧组细胞凋亡率、细胞中活性氧(ROS)、丙二醛(MDA)、8-羟基脱氧鸟苷(8-OHDG)含量及bcl-2相关X蛋白(bax)、细胞色素C(Cyt-C)、含半胱氨酸的天冬氨酸蛋白水解酶3(Caspase-3)的表达量均明显高于常氧组。0. 5 NAC组、1. 0 NAC组细胞OD490值、T-AOC量及Bcl-2、pAMPK、SIRT1表达量均明显高于缺氧组; 0. 5 NAC组、1. 0 NAC组细胞凋亡率、ROS、MDA、8-OHDG含量及Caspase-3、Cyt-C、Bax的表达量均明显低于缺氧组。NAC+8-bAMP组细胞OD490值、T-AOC及Bcl-2、p-AMPK、SIRT1表达量均明显低于1. 0 NAC组; NAC+8-bAMP组凋亡率、ROS、MDA、8-OHDG含量及Caspase-3、Cyt-C、Bax的表达量均明显高于1. 0 NAC组。结论 NAC能够通过激活AMPK/SIRT1通路来减轻氧化应激及线粒体凋亡介导的脑血管内皮细胞损伤。     

Ligustilide ameliorates cognitive impairment via AMPK/SIRT1 pathway in vascular dementia rat

Metabolic Brain Disease - Vascular dementia (VaD) is the second cause of dementia after Alzheimer’s disease. Ligustilide (LIG) is one of the main active ingredients of traditional Chinese...     

Pterostilbene Decreases Cardiac Oxidative Stress and Inflammation via Activation of AMPK/Nrf2/HO-1 Pathway in Fructose-Fed Diabetic Rats

Purpose

Oxidative stress has a pivotal role in the pathogenesis of diabetes-associated cardiovascular problems, which has remained a primary cause of the increased morbidity and mortality in diabetic patients. It is of paramount importance to prevent the diabetes-associated cardiac complications by reducing oxidative stress with the help of nutritional or pharmacological agents. Pterostilbene (PT), the primary antioxidant in blueberries, has recently gained attention for its promising health benefits in metabolic and cardiac diseases. However, the mechanism whereby PT reduces diabetic cardiac complications is currently unknown.

Methods

Sprague-Dawley rats were fed with 65% fructose diet with or without PT (20 mg kg^?1 day^?1) for 8 weeks. Heart rate and blood pressure were measured by tail-cuff apparatus. Real-time PCR and western blot experiments were executed to quantify the expression levels of mRNA and protein, respectively.

Results

Fructose-fed rats demonstrated cardiac hypertrophy, hypertension, enhanced myocardial oxidative stress, inflammation and increased NF-κB expression. Administration of PT significantly decreased cardiac hypertrophy, hypertension, oxidative stress, inflammation, NF-κB expression and NLRP3 inflammasome. We demonstrated that PT improved mitochondrial biogenesis as evidenced by increased protein expression of PGC-1α, complex III and complex V in fructose-fed diabetic rats. Further, PT increased protein expressions of AMPK, Nrf2, HO-1 in cardiac tissues, which may account for the prevention of cardiac oxidative stress and inflammation in fructose-fed rats.

Conclusions

Collectively, PT reduced cardiac oxidative stress and inflammation in diabetic rats through stimulation of AMPK/Nrf2/HO-1 signalling.

     

The Protective Role of Bmal1-Regulated Autophagy Mediated by HDAC3/SIRT1 Pathway in Myocardial Ischemia/Reperfusion Injury of Diabetic Rats

Cardiovascular Drugs and Therapy - Histone deacetylase 3 (HDAC3) and silent information regulator 1 (SIRT1) are histone deacetylases that regulate important metabolic pathways and play important...     

Ischaemic Preconditioning Protects Cardiomyocytes from Anthracycline-Induced Toxicity via the PI3K Pathway

Purpose

Anthracyclines cause chronic irreversible cardiac failure, but the mechanism remains poorly understood. Emerging data indicate that cardiac damage begins early, suggesting protective modalities delivered in the acute stage may confer prolonged benefit. Ischaemic preconditioning (IPC) activates the pro-survival reperfusion injury salvage kinase (RISK) pathway which involves PI3-kinase and MAPK/ERK1/2.

Methods

We investigated whether simulated IPC (sIPC), in the form of a sublethal exposure to a hypoxic buffer simulating ischaemic conditions followed by reoxygenation, protects primary adult rat cardiomyocytes against anthracycline-induced injury. PI3-kinase and MAPK/ERK1/2 were inhibited using LY294002, and PD98059. The role of reactive oxygen species (ROS), mitochondrial membrane potential (Δψ_m) and mitochondrial permeability transition pore (mPTP) were also investigated in doxorubicin-treated cells. We further examined whether sIPC protected HeLa cancer cells from doxorubicin-induced death.

Results

sIPC protected cardiomyocytes against doxorubicin-induced death (35.4?±?1.7% doxorubicin vs 14.7?±?1.5% doxorubicin + sIPC; p?<?0.01). This protection was abrogated by the PI3-kinase inhibitor, LY294002, but not the MAPK/ERK1/2 inhibitor, PD98059. A ROS scavenger failed to rescue cardiomyocytes from doxorubicin toxicity, and no significant influence on Δψ_m or mPTP opening was identified after subjecting cells to a doxorubicin insult. Importantly, sIPC did not protect HeLa cancer cells from doxorubicin-induced death.

Conclusion

sIPC is able to protect cardiomyocytes against anthracycline injury via a pathway involving PI3-kinase. This mechanism appears to be independent of ROS, changes to Δψ_m, and mPTP. Further investigation of the mechanism of sIPC-induced protection against anthracycline-injury is warranted.

     

The Caspase 1 Inhibitor VX-765 Protects the Isolated Rat Heart via the RISK Pathway

Purpose

Protecting the heart from ischaemia-reperfusion (IR) injury is a major goal in patients presenting with an acute myocardial infarction. Pyroptosis is a novel form of cell death in which caspase 1 is activated and cleaves interleukin 1β. VX-785 is a highly selective, prodrug caspase 1 inhibitor that is also clinically available. It has been shown to be protective against acute IR in vivo rat model, and therefore might be a promising possibility for future cardioprotective therapy. However, it is not known whether protection by VX-765 involves the reperfusion injury salvage kinase (RISK) pathway. We therefore investigated whether VX-765 protects the isolated, perfused rat heart via the PI3K/Akt pathway and whether protection was additive with ischaemic preconditioning (IPC).

Methods

Langendorff-perfused rat hearts were subject to ischaemia and reperfusion injury in the presence of 30 μM VX-765, with precedent IPC, or the combination of VX-765 and IPC.

Results

VX-765 reduced infarct size (28 vs 48% control; P?<?0.05) to a similar extent as IPC (30%; P?<?0.05). The PI3 kinase inhibitor, wortmannin, abolished the protective effect of VX-765. Importantly in the model used, we were unable to show additive protection with VX-765 + IPC.

Conclusions

The caspase 1 inhibitor, VX-765, was able to reduce myocardial infarction in a model of IR injury. However, the addition of IPC did not demonstrate any further protection.

     

心肌营养素-1诱导心肌细胞肥大及辛伐他汀的干预作用

目的观察细胞因子心肌营养素1(CT-1)诱导大鼠心肌细胞的肥大效应,探讨辛伐他汀(Sim)对这一过程的干预作用及其信号转导机制。方法以培养的新生Sprague-Dawley(SD)大鼠心肌细胞为实验模型,分为对照组,CT-1诱导组,CT-1 Sim组,CT-1 Sim 甲羟戊酸(MVA)组,CT-1 AG490(JAK2拮抗剂)组。应用图像分析系统测定心肌细胞表面积,3H-亮氨酸掺入法测定心肌细胞蛋白合成速率,逆转录聚合酶链式反应(RT-PCR)检测心钠素(ANP)mRNA表达,RT-PCR检测细胞因子信号通路JAK/STAT的mRNA表达水平。结果(1)与对照组相比,CT-1组心肌细胞表面积,3H-亮氨酸掺入率,ANPmRNA表达水平均明显增高(P<0.01),JAK2拮抗剂AG490可显著的抑制CT-1的作用(P<0.01)。(2)与CT-1组相比,辛伐他汀共培养后心肌细胞表面积,3H-亮氨酸掺入率,ANPmRNA表达水平明显减小(P<0.01),外源性甲羟戊酸可显著的抑制辛伐他汀的作用(P<0.01);(3)CT-1可使心肌细胞JAK-STAT的mRNA表达水平显著增强,辛伐他汀显著抑制CT-1诱导心肌细胞JAK-STATmR-NA表达水平增高(P<0.01),而MVA和AG490可部分阻断辛伐他汀的效应(P<0.01)。结论心肌营养素1能够诱导心肌细胞肥大,辛伐他汀可抑制其这一过程并可能与细胞因子信号通路JAK-STAT活化有关。     

心肌营养素-1诱导心肌细胞肥大及辛伐他汀的干预作用

目的 观察细胞因子心肌营养素-1(CT-1)诱导大鼠心肌细胞的肥大效应,探讨辛伐他汀(Sim)对这一过程的干预作用及其信号转导机制.方法 以培养的新生Sprague-Dawley(SD)大鼠心肌细胞为实验模型,分为对照组,CT-1诱导组,CT-1 Sim组,CT-1 Sim 甲羟戊酸(MVA)组,CT-1 AG490(JAK2拮抗剂)组.应用图像分析系统测定心肌细胞表面积,3H-亮氨酸掺入法测定心肌细胞蛋白合成速率,逆转录聚合酶链式反应(RT-PCR)检测心钠素(ANP)mRNA表达,RT-PCR检测细胞因子信号通路JAK/STAT的mRNA表达水平.结果 (1)与对照组相比,CT-1组心肌细胞表面积,3H-亮氨酸掺入率,ANP mRNA表达水平均明显增高(P＜0.01),JAK2拮抗剂AG490可显著的抑制CT-1的作用(P＜0.01).(2)与CT-1组相比,辛伐他汀共培养后心肌细胞表面积,3H-亮氨酸掺入率,ANP mRNA表达水平明显减小(P＜0.01),外源性甲羟戊酸可显著的抑制辛伐他汀的作用(P＜0.01);(3)CT-1可使心肌细胞JAK-STAT的mRNA表达水平显著增强,辛伐他汀显著抑制CT-1诱导心肌细胞JAK-STAT mRNA表达水平增高(P＜0.01),而MVA和AG490可部分阻断辛伐他汀的效应(P＜0.01).结论 心肌营养素-1能够诱导心肌细胞肥大,辛伐他汀可抑制其这一过程并可能与细胞因子信号通路JAK-STAT活化有关.     

Sphingosine-1-Phosphate Protects Intestinal Epithelial Cells from Apoptosis Through the Akt Signaling Pathway

Objective The regulation of apoptosis of intestinal mucosal cells is important in maintenance of normal intestinal physiology. Summary Sphingosine-1-phosphate (S1P) has been shown to play a critical role in cellular protection to otherwise lethal stimuli in several nonintestinal tissues. Methods The current study determines whether S1P protected normal intestinal epithelial cells (IECs) from apoptosis and whether Akt activation was the central pathway for this effect. Results S1P demonstrated significantly reduced levels of apoptosis induced by tumor necrosis factor-alpha (TNF-α)/cycloheximide (CHX). S1P induced increased levels of phosphorylated Akt and increased Akt activity, but did not affect total amounts of Akt. This activation of Akt was associated with decreased levels of both caspase-3 protein levels and of caspase-3 activity. Inactivation of Akt by treatment with the PI3K chemical inhibitor LY294002 or by overexpression of the dominant negative mutant of Akt (DNMAkt) prevented the protective effect of S1P on apoptosis. Additionally, silencing of the S1P-1 receptor by specific siRNA demonstrated a lesser decrease in apoptosis to S1P exposure. Conclusion These results indicate that S1P protects intestinal epithelial cells from apoptosis via an Akt-dependent pathway.     

Resveratrol Attenuates Intermittent Hypoxia-Induced Lung Injury by Activating the Nrf2/ARE Pathway

Lung - Obstructive sleep apnea (OSA) is associated with lung injury. As a novel pathophysiological hallmark of OSA, chronic intermittent hypoxia (CIH) enhances apoptosis. The present study aims to...     

Fish oil alleviates liver injury induced by intestinal ischemia/reperfusion via AMPK/SIRT-1/autophagy pathway

AIM To evaluate whether fish oil(FO) can protect liver injury induced by intestinal ischemia/reperfusion(I/R) via the AMPK/SIRT-1/autophagy pathway.METHODS Ischemia in wistar rats was induced by superior mesenteric artery occlusion for 60 min and reperfusion for 240 min. One milliliter per day of FO emulsion or normal saline was administered by intraperitoneal injection for 5 consecutive days to each animal. Animals were sacrificed at the end of reperfusion. Blood andtissue samples were collected for analyses. AMPK, SIRT-1, and Beclin-1 expression was determined in lipopolysaccharide(LPS)-stimulated HepG2 cells with or without FO emulsion treatment.RESULTS Intestinal I/R induced significant liver morphological changes and increased serum alanine aminotransferase and aspartate aminotransferase levels. Expression of p-AMPK/AMPK, SIRT-1, and autophagy markers was decreased whereas tumor necrosis factor-α(TNF-α) and malonaldehyde(MDA) were increased. FO emulsion blocked the changes of the above indicators effectively. Besides, in LPS-stimulated HepG2 cells, small interfering RNA(siRNA) targeting AMPK impaired the FO induced increase of p-AMPK, SIRT-1, and Beclin-1 and decrease of TNF-α and MDA. SIRT-1 siRNA impaired the increase of SIRT-1 and Beclin-1 and the decrease of TNF-α and MDA.CONCLUSION Our study indicates that FO may protect the liver against intestinal I/R induced injury through the AMPK/SIRT-1/autophagy pathway.     

LB100 ameliorates nonalcoholic fatty liver disease via the AMPK/Sirt1 pathway

BACKGROUND It is well known that nonalcoholic fatty liver disease(NAFLD) is associated with insulin resistance(IR).LB100,a serine/threonine protein phosphatase 2 A(PP2 A)inhibitor,is closely related to IR.However,there is little data regarding its direct influence on NAFLD.AIM To elucidate the effect and underlying mechanism of LB100 in NAFLD.METHODS After 10 wk of high fat diet(HFD) feeding,male C57 BL/6 mice were injected intraperitoneally with vehicle or LB100 for an additional 6 wk(three times a week).The L02 cell line was treated with LB100 and free fatty acids(FFAs) for 24 h.Hematoxylin and eosin and oil red O staining were performed for histological examination.Western blot analysis was used to detect the protein expression of Sirtuin 1(Sirt1),total and phosphorylated AMP-activated protein kinase α(AMPKα),and the proteins involved in lipogenesis and fatty acid oxidation.The m RNA levels were determined by q PCR.Pharmacological inhibition of AMPK was performed to further examine the exact mechanism of LB100 in NAFLD.RESULTS LB100 significantly ameliorated HFD-induced obesity,hepatic lipid accumulation and hepatic injury in mice.In addition,LB100 significantly downregulated the protein levels of acetyl-Co A carboxylase,sterol regulatory element-binding protein 1 and its lipogenesis target genes,including stearoyl-Co A desaturase-1 and fatty acid synthase,and upregulated the levels of proteins involved in fatty acid β-oxidation,such as peroxisome proliferator-activated receptor α(PPARα),peroxisome proliferator-activated receptor gamma coactivator-1α(PGC-1α),carnitine palmitoyltransferase 1α,acyl-Co A oxidase 1 and uncoupling protein 2,as well as the upstream mediators Sirt1 and AMPKα in the livers of HFD-fed mice.In vitro,LB100 alleviated FFA-induced lipid accumulation in L02 cells through the AMPK/Sirt1 signaling pathway.Further studies showed that the curative effect of LB100 on lipid accumulation was abolished by inhibiting AMPKα in L02 cells.CONCLUSION PP2 A inhibition by LB100 significantly ameliorates hepatic steatosis by regulating hepatic lipogenesis and fatty acid oxidation via the AMPK/Sirt1 pathway.LB100 may be a potential therapeutic agent for NAFLD.     

Resveratrol enhanced FOXO3 phosphorylation via synergetic activation of SIRT1 and PI3K/Akt signaling to improve the effects of exercise in elderly rat hearts

Exercise training is considered a benefit to heart function, but the benefit in aging hearts remains unknown. Activation of the PI3K-Akt survival pathway and suppression of Fas/FADD/caspase-8 apoptotic signaling by exercise training in hearts from young subjects have been described in our previous studies. However, the mechanisms are still unclear and need to be explored in aging hearts. Thus, 18-month-old rats were used as a model and underwent swimming exercise training, resveratrol treatment (15 mg/kg/day), or exercise training with resveratrol treatment for 1 month. The results showed that heart function in each group improved. However, the 18-month-old rats in the exercise-only group experienced the slightly inevitable impact of increased TNF-α, cell apoptosis, and fibrosis. In the protein analysis, the PI3K-Akt pathway was slightly increased with exercise training and resveratrol treatment, but Sirtuin 1 (SIRT1) was only highly activated with resveratrol treatment in the aged rat hearts. Moreover, the exercise training plus resveratrol group benefited from SIRT1 and PI3K-Akt dual pathways and blocked FOXO3 accumulation. Our experimental results strongly suggest that resveratrol treatment improves the beneficial effects of exercise training in aging rat hearts.     

Remote Postconditioning Induced by Trauma Protects the Mouse Heart against Ischemia Reperfusion Injury. Involvement of the Neural Pathway and Molecular Mechanisms

Purpose

Abdominal superficial surgical incision elicits cardioprotection against myocardial ischemia reperfusion (I/R) injury in mice. This cardioprotective phenomenon, termed remote preconditioning of trauma (RPCT), results in an 80 to 85 % reduction in cardiac infarct size. We evaluated cardioprotection and the molecular mechanisms of remote postconditioning of trauma (RPostCT) in a murine I/R injury model.

Methods

Mice were analyzed using a previously established I/R injury model. An abdominal superficial surgical incision was made 45 min after myocardial ischemia at the end of coronary occlusion, and infarct size was determined 24 h after reperfusion.

Results

The results indicated that a strong cardioprotective effect occurred during RPostCT (56.94 ± 2.71 % sham vs. 15.58 ± 2.16 % RPostCT; the mean area of the infarct divided by the mean area of the region at risk; p ≤ 0.05; n = 10). Furthermore, pharmacological intervention revealed neurogenic signaling involvement in the beneficial effects of RPostCT via sensory and sympathetic thoracic nerves. Pharmacological experiments in transgenic mice demonstrated that bradykinin receptors, β-adrenergic receptors (AR), and protein kinase C were implicated in the cardioprotective effects of RPostCT.

Conclusions

RPostCT significantly decreased myocardial infarction size via neurogenic transmission and various signaling pathways. This study describes a new cardiac I/R injury prevention method that might lead to the development of therapies that are more clinically relevant for myocardial I/R injury.

     

Bezold-Jarisch-Like Phenomenon Induced by Radiofrequency Ablation of a Left Posteroseptal Accessory Pathway via the Coronary Sinus

RF Ablation-Induced Bezold-Jarisch Phenomenon. We report a case of asystole induced by radiofrequency (RF) ablation via the coronary sinus in a 35-year-old man suffering from symptomatic left posteroseptal accessory pathway. RF application provoked progressive slowing of the sinus rhythm, disappearance of the preexcitation, and an 8-second period of asystole followed by atrial fibrillation. The causal mechanism proposed is a strong stimulation of va-gal afferent pathways linked with sensory endings of the inferoposterior myocardial wall leading to a Bezold-Jarisch-like phenomenon.