PI3K/Akt信号通路在脓毒症肾脏损伤诱导的自噬中的调节作用*

 目的：研究脓毒症造成肾脏损伤时的自噬情况以及磷脂酰肌醇3-激酶（PI3K）/蛋白激酶B(Akt)信号通路的调节作用。方法：对大鼠盲肠进行结扎与穿刺（CLP）,对肾脏组织切片进行HE染色,并测定血清尿素氮和肌酐。通过Western blotting定量分析CLP大鼠肾脏损伤发生后不同时点自噬相关分子微管相关蛋白轻链3（LC3）Ⅰ/Ⅱ、beclin-1和Akt蛋白磷酸化的表达情况;体外用LPS诱导人近端肾小管上皮细胞株HK-2发生自噬,检测不同浓度LPS和不同刺激时间自噬相关分子LC3Ⅰ/Ⅱ和Akt蛋白磷酸化的表达情况;进一步使用PI3K抑制剂、Akt抑制剂和LPS刺激HK-2细胞观察自噬相关蛋白的表达情况及细胞的凋亡水平。结果：同对照组相比,CLP大鼠显微镜下可见肾损伤的典型病理改变,血清尿素氮和肌酐均有上升。CLP肾脏损伤发生后,自噬相关蛋白LC3Ⅰ/Ⅱ、beclin-1含量及Akt磷酸化水平均有上升。LPS刺激HK-2细胞后,随着刺激浓度的增加,p-Akt(308)表达量逐渐提高,而LC3Ⅰ/Ⅱ及p-Akt(472)的表达量在10 mg/L LPS刺激组最高。随着刺激时间的延长,p-Akt(308)表达量逐渐提高;LC3Ⅰ/Ⅱ表达量同p-Akt(472)在刺激8 h时最高;使用PI3K抑制剂及Akt抑制剂后,LPS诱导的LC3表达显著下调,HK-2细胞凋亡明显增加。结论：CLP肾脏损伤发生时可以诱导自噬发生, PI3K／Akt信号通路在其中发挥重要调节作用。     

PI3K/Akt信号通路上调急性肺损伤大鼠肺泡上皮钠通道表达

目的 探讨PI3K/Akt信号通路对急性肺损伤(ALI)大鼠肺泡上皮钠通道(ENaC)α、β和γ亚基表达的影响.方法 成年SD大鼠随机分为对照组、ALI组(脂多糖)、胰岛素组及渥曼青霉素组,每组5只.观察肺组织病理改变,收集支气管肺泡灌洗液(BALF),测量总肺水含量,RT-PCR和Western blot测定ENaC mRNA和蛋白、p-Akt表达.结果 胰岛素组BALF蛋白含量、髓过氧化物酶(MPO)活性、总肺水含量较ALI组显著减少(P＜0.05),渥曼青霉素组BALF蛋白含量、MPO活性及总肺水含量较胰岛素组显著增加(P＜0.05).ALI组α-、β-和γ-ENaC蛋白表达显著低于对照组(0.33 ±0.06 vs 1.27 ±0.07,0.18±0.04 vs 0.72±0.04,0.37±0.04 vs0.69±0.05)(P＜0.05).胰岛素组蛋白表达α-ENaC(2.19 ±0.04)、β-ENaC(1.18 ±0.07)和γ-ENaC(1.18 ±0.08)显著高于ALI组(P＜0.05).渥曼青霉素组蛋白表达α-ENaC(0.86 ±0.09)、β-ENaC (0.58±0.05)和γ-ENaC (0.59±0.02)显著低于胰岛素组(P＜ 0.05).胰岛素组ENaC mRNA和p-Akt较ALI组显著升高(P＜0.05).渥曼青霉素组ENaC mRNA和p-Akt较胰岛素组显著降低(P＜0.05).结论 激活H3K/Akt通路上调3种ENaC亚基表达,从而清除肺水肿液.     

长春西汀注射液减轻脂多糖诱导的大鼠急性肺损伤

目的:观察长春西汀注射液对脂多糖(lipopolysaccharide,LPS)诱导大鼠急性肺损伤(acute lung injury,ALI)的作用,并研究初步的作用机制。方法:雄性Wistar大鼠50只,随机分为正常对照组(control)、模型组(ALI组)以及长春西汀低剂量组、中剂量组和高剂量组,每组10只。正常对照组股静脉注射0.9%氯化钠注射液(5 m L/kg);模型组股静脉注射LPS 10 mg/kg;长春西汀低、中和高剂量组股静脉注射LPS 10 mg/kg,30 min后分别腹腔注射长春西汀注射液0.2 mg/kg、0.7 mg/kg和1.2 mg/kg。伊红染色观察肺部组织病理学切片,TUNEL法检测肺组织的细胞凋亡,分光光度法检测并计算肺组织髓过氧化物酶(MPO)活性,Western blot法检测肺组织中NF-κB、ICAM-1、VCAM-1、Bax与Bcl-2的蛋白水平。结果:与模型组相比,采用长春西汀给药后,明显减轻急性肺损伤的肺组织结构损伤与炎性细胞浸润,降低肺组织凋亡的细胞数与MPO活性,下调细胞中NF-κB、ICAM-1、VCAM-1与Bax的蛋白表达水平,上调Bcl-2的蛋白表达水平。结论:长春西汀注射液对急性肺损伤大鼠的肺组织具有保护作用,可能与降低肺组织中MPO活性,以及调控NF-κB、ICAM-1、VCAM-1、Bax与Bcl-2蛋白表达水平有关。     

丙泊酚对肝缺血再灌注大鼠肺损伤及PI3K/Akt通路的影响

 目的：通过研究丙泊酚对全肝缺血再灌注大鼠肺组织磷脂酰肌醇3-激酶/蛋白激酶B（PI3K/Akt）信号通路活化的影响,探讨丙泊酚在全肝缺血再灌注肺损伤中的作用机制。方法：SD 大鼠66只,随机分成4组,假手术组(S组,n=6)、肝缺血再灌注组 (IR 组,n=24)、丙泊酚预处理组 (P 组,n=24)和丙泊酚预处理+PI3K阻断剂 wortmannin 组 (P+W组,n=12),IR 组和 P 组按再灌注 1 h、3 h、6 h和12 h 分为 4 个亚组,P+W 组按再灌注 3 h和6 h分为 2 个亚组。S 组仅解剖肝门,不结扎;IR 组采用结扎肝蒂全肝缺血 30 min、再灌注的方法建立大鼠肝缺血再灌注模型;P 组缺血前 10 min 经尾静脉缓慢注射负荷剂量的丙泊酚 20 mg·kg-1,再以 20 mg·kg-1·h-1的速度尾静脉持续泵注直至处死,余同IR 组;P+W组缺血前经尾静脉注射 PI3K 阻断剂 wortmannin 15 μg·kg-1,余同 P 组。各组于再灌注 1 h、3 h、6 h和12 h时处死大鼠取肺组织。采用 Western  blotting 检测大鼠肺组织中总 Akt（t-Akt）、磷酸化 Akt（p-Akt)及 Bcl-2 蛋白表达水平;用 Annexin V-FITC/PI 法检测肺细胞凋亡率。结果：与 S 组比较,IR 组、P 组和 P+W 组肺组织中 p-Akt和 Bcl-2蛋白表达水平和肺细胞凋亡率升高（P<0.05）;与 IR 组比较,P 组 p-Akt 和 Bcl-2 蛋白表达水平升高,肺细胞凋亡率降低（P<0.05）,P+W 组上述指标表达差异无统计学意义（P>0.05）;与 P 组比较,P+W 组 p-Akt 和 Bcl-2蛋白表达水平下降,肺细胞凋亡率升高（P<0.05）;各组中 t-Akt 蛋白表达差异无统计学意义（P>0.05）。结论：丙泊酚可以减轻大鼠肝缺血再灌注诱发的肺损伤,其机制可能与 PI3K/Akt 信号通路的激活进而减轻肺细胞凋亡有关。     

血必净通过激活PI3K/Akt/mTOR信号通路减轻大鼠睾丸缺血再灌注损伤

目的:探究血必净对缺血再灌注(I/R)损伤大鼠睾丸的保护作用及其相关机制。方法:45只雄性SD大鼠随机分为对照组、模型组、血必净低剂量组、血必净高剂量组和地塞米松组(均n=9);除对照组大鼠外,其它各组大鼠构建睾丸扭转复位模型,术后低、高剂量组及地塞米松组大鼠分别腹腔注射0.5和2 mL·kg^-1·d^-1血必净及0.5 mL·kg^-1·d^-1地塞米松。用药第3、7和14天取各组大鼠左侧睾丸,采用HE染色观察各组大鼠睾丸组织病理学改变;生化检测各组大鼠睾丸组织中丙二醛(MDA)、超氧化物歧化酶(SOD)、内皮素1(ET-1)和一氧化氮(NO)水平,Western blot检测各组大鼠睾丸组织中细胞周期相关蛋白、细胞凋亡相关蛋白以及PI3K/Akt/mTOR信号通路相关蛋白的水平。结果:血必净可显著减轻I/R大鼠睾丸损伤,显著升高I/R大鼠睾丸组织中SOD活性,降低MDA、ET-1和NO的含量,抑制I/R损伤组织中的氧化应激,介导细胞周期和细胞凋亡相关因子的表达,并显著升高I/R大鼠睾丸中p-PI3K、...     

Quercetin postconditioning attenuates myocardial ischemia/reperfusion injury in rats through the PI3K/Akt pathway

Quercetin (Que), a plant-derived flavonoid, has multiple benefical actions on the cardiovascular system. The current study investigated whether Que postconditioning has any protective effects on myocardial ischemia/reperfusion (I/R) injury in vivo and its potential cardioprotective mechanisms. Male Sprague-Dawley rats were randomly allocated to 5 groups (20 animals/group): sham, I/R, Que postconditioning, Que+{"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002 [a phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway inhibitor], and {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002+I/R. I/R was produced by 30-min coronary occlusion followed by 2-h reperfusion. At the end of reperfusion, myocardial infarct size and biochemical changes were compared. Apoptosis was evaluated by both TUNEL staining and measurement of activated caspase-3 immunoreactivity. The phosphorylation of Akt and protein expression of Bcl-2 and Bax were determined by Western blotting. Que postconditioning significantly reduced infarct size and serum levels of creatine kinase and lactate dehydrogenase compared with the I/R group (all P<0.05). Apoptotic cardiomyocytes and caspase-3 immunoreactivity were also suppressed in the Que postconditioning group compared with the I/R group (both P<0.05). Akt phosphorylation and Bcl-2 expression increased after Que postconditioning, but Bax expression decreased. These effects were inhibited by {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002. The data indicate that Que postconditioning can induce cardioprotection by activating the PI3K/Akt signaling pathway and modulating the expression of Bcl-2 and Bax proteins.     

H_2S通过抑制TLR4/MyD88/PI3K信号通路减轻尿源性脓毒血症诱导的急性肾损伤

目的:探讨硫化氢(H_2S)减轻尿源性脓毒血症诱导的急性肾损伤的作用机制。方法:40只新西兰白兔随机分为对照组、假手术组、脓毒血症模型组、脓毒血症模型Na HS处理组和脓毒血症模型Na HS联合TAK-242(TLR4抑制剂)处理组,每组8只。各组分别按分组处理72 h后,采用HE染色观察兔肾组织病理学变化;使用全自动生化分析仪检测血尿素氮(BUN)和血清肌酐(SCr)水平;采用ELISA法检测血液中中性粒细胞明胶酶相关脂质运载蛋白(NGAL)、肾损伤分子1(KIM-1)、降钙素原(PCT)以及炎症因子白细胞介素1β(IL-1β)、白细胞介素6(IL-6)和肿瘤坏死因子α(TNF-α)的水平;采用Western blot检测TLR4/MyD88/PI3K信号通路相关蛋白的表达。结果:与对照组相比,脓毒血症兔肾组织呈现明显损伤,Na HS处理后肾脏病理明显改善,且血液中BUN、SCr、NGAL、KIM-1、PCT、IL-1β、IL-6和TNF-α水平显著提高(P 0.05),但Na HS处理或联合TAK-242处理后显著降低;脓毒血症兔肾脏组织中的TLR4、MyD88、p-PI3K和p-Akt蛋白水平显著升高;Na HS处理或抑制TLR4则显著抑制TLR4/MyD88/PI3K信号通路激活。结论:H_2S可能通过抑制TLR4/MyD88/PI3K信号通路减少炎症因子及肾损伤因子的释放,从而有效减轻尿源性脓毒血症诱导的急性肾损伤。     

PI3K/Akt和JAK2/STAT3信号转导通路在SO_2抗大鼠肢体缺血再灌注致急性肺损伤中的作用

目的:探讨PI3K/Akt和JAK2/STAT3信号转导通路在二氧化硫(SO2)抗肢体缺血再灌注(I/R)致急性肺损伤中的作用。方法:应用双大腿根部绑扎止血带复制大鼠双后肢缺血再灌注肺损伤模型。在再灌注前20 min腹腔注射Na2SO3/Na HSO3;在再灌注前1 h静脉注射Stattic或LY294002。应用TUNEL、ELISA、Western blot等方法检测细胞凋亡、细胞因子表达及相关信号通路蛋白表达的情况。结果:与对照组相比,I/R组的MDA及MPO含量、肺系数、细胞凋亡指数、细胞因子表达以及p-STAT3、p-Akt蛋白的水平均显著增高;当应用Na2SO3/Na HSO3后,上述反映肺损伤的各项指标均下降。Western blot检测结果显示I/R后,肺组织中p-STAT3和p-Akt蛋白的水平均明显增加。而应用Na2SO3/Na HSO3后,p-Akt蛋白的水平继续增加,但p-STAT3蛋白的水平却减少(P0.05)。结论:JAK2/STAT3和PI3K/Akt信号通路都参与了SO2抗肢体缺血再灌注致急性肺损伤的作用。JAK2/STAT3通路的活化,能够使I/R损伤加重;相反,PI3K/Akt信号通路的活化,可以使I/R损伤减弱。此外,JAK2/STAT3和PI3K/Akt信号通路之间存在交互作用。     

Galantamine protects against lipopolysaccharide-induced acute lung injury in rats

Lipopolysaccharide (LPS)-induced endotoxemia triggers the secretion of proinflammatory cytokines and can cause acute lung injury (ALI). The high mobility group box 1 (HMGB1) protein plays an important role as a late mediator of sepsis and ALI. Galantamine (GAL) is a central acetylcholinesterase inhibitor that inhibits the expression of HMGB1. This study evaluated the effects of GAL by measuring levels of inflammatory mediators and observing histopathological features associated with LPS-induced ALI. Sixty 8-10 week old male Sprague-Dawley rats (200-240 g) were randomized into three groups as follows: control group, LPS group (7.5 mg/kg LPS), and LPS+GAL group (5 mg/kg GAL before LPS administration). Histopathological examination of lung specimens obtained 12 h after LPS administration was performed to analyze changes in wet-to-dry (W/D) weight ratio, myeloperoxidase (MPO) activity, and HMGB1 expression level. Additionally, plasma concentrations of tumor necrosis factor-α, interleukin-6, and HMGB1 were measured using an enzyme-linked immunosorbent assay at 0 (baseline), 3, 6, 9, and 12 h after LPS administration. Mortality in the three groups was recorded at 72 h. LPS-induced ALI was characterized by distortion of pulmonary architecture and elevation of MPO activity, W/D weight ratio, and levels of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin-6, and HMGB1. Pretreatment with GAL significantly reduced the LPS-induced lung pathological changes, W/D weight ratio, levels of pro-inflammatory cytokines and MPO activity (ANOVA). Moreover, GAL treatment significantly decreased the mortality rate (ANOVA). In conclusion, we demonstrated that GAL exerted a protective effect on LPS-induced ALI in rats.     

EPO通过激活PI3K/Akt途径上调HSP70的表达对低温下心衰大鼠起保护作用

目的:评价红细胞生成素(erythropoietin,EPO)对低温环境下心衰大鼠的影响,探讨其可能的作用机制。方法:80只SD大鼠随机分5组,分别为对照组(CON组)、心衰低温组(HFLT组)、心衰常温组(HFNT组)、心衰低温EPO组(HFLT+EPO组)和心衰低温LY294002组(HFLT+EPO+LY组)。然后将所有大鼠放置于气候箱中(CON、HFLT、HFLT+EPO和HFLT+EPO+LY组为低温环境;HFNT组为常温)。超声心动图检测各组大鼠心功能,然后处死大鼠并留取心脏标本,TUNEL法测心肌细胞凋亡,荧光定量PCR测心肌组织中Fas和PI3K mRNA的表达,Western blot测大鼠心肌组织中热休克蛋白70(HSP70)、Akt和p-Akt的水平。结果:低温下心衰大鼠心功能明显低于常温下心衰大鼠,HFLT+EPO组大鼠心功能较HFLT组明显改善,给予LY294002干预后HFLT+EPO+LY组大鼠心功能明显低于HFLT+EPO组;HFLT组及HFNT组凋亡指数均高于CON组(P0.01),HFLT组凋亡指数又明显高于HFNT组(P0.05),HFLT+EPO组凋亡指数明显低于HFLT组(P0.01)。Fas mRNA在HFLT组心肌组织中的表达明显高于HFNT组,PI3K mRNA在HFLT组和HFNT组心肌组织中的表达差异无统计学显著性,HFLT+EPO组心肌组织中Fas的mRNA表达明显低于HFLT组(P0.01)和HFLT+EPO+LY组(P0.05),而PI3K的mRNA表达则明显高于HFLT组和HFLT+EPO+LY组(P0.05)。HFLT+EPO组大鼠心肌组织中p-Akt和HSP70的水平明显高于HFLT组和HFLT+EPO+LY组(P0.05),CON、HFLT和HFNT组大鼠心肌组织中p-Akt和HSP70的蛋白水平差异无统计学显著性。所有大鼠心肌组织中Akt的水平差异无统计学显著性。结论:EPO活化PI3K/Akt后,上调内源性保护途径中HSP70的表达并抑制细胞凋亡,从而对低温下的心衰大鼠心脏起保护作用。     

Mannose prevents lipopolysaccharide-induced acute lung injury in rats

Objective: To investigate the effect of mannose on lipopolysaccharide (LPS) induced acute lung injury (ALI) in rats. Methods: Ten groups of Sprague–Dawley rats were used: 1) the control group received an intratracheal instillation of saline, 2) the LPS group received an intratracheal instillation of LPS (3 mg/kg), 3–6) the mannose groups were injected i.v. with 15, 45, 135, and 405 mg/kg mannose, 7–9) the glucose, galactose, and fructose groups were injected with different hexoses (135 mg/kg), and 10) the dexamethasone (DXM) group was injected with DXM (2 mg/kg). In groups 2–8, LPS was administered after injection of drugs. Lung wet/dry weight ratio, permeability index (PPI), total leukocytes and polymorphonuclear neutrophils (PMNs) counts in bronchoalveolar lavage fluid (BALF), myeloperoxidase (MPO) and superoxide dismutase (SOD) activity, tumor necrosis factor (TNF)-α and interleukin (IL)-10 in lung and BALF were determined. Results: Pre-treatment with mannose attenuated pulmonary edema and protein exudation in a dose-dependent manner, the maximal effect was similar to or greater than that of DXM. Mannose also prevented the inflammatory cell accumulation, although the maximal effect was weaker than that of DXM. Mannose was more effective than DXM in inhibiting MPO activity and restoring SOD activity. Moreover, it inhibited production of TNF-α and IL-10. Histological changes of the lungs were also ameliorated by mannose. There were no significant improvements observed in rats pre-treated with glucose, galactose or fructose. Conclusions: Mannose is effective in reducing LPS-induced ALI. Project supported by the National Natural Science Foundation of China, No. 30670930 and the Science and Technology Department of Zhejiang Province (No.2004C23011) Received 4 March 2007; returned for revision 13 May 2007; returned for final revision 17 July 2007; accepted by M. Katori 12 September 2007     

磷脂酰肌醇3激酶/蛋白激酶B/雷帕霉素靶蛋白信号通路在肺部疾病中的研究进展

磷脂酰肌醇3激酶/蛋白激酶B/雷帕霉素靶蛋白(phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin,PI3K/Akt/mTOR)是细胞内重要信号通路,在细胞生长、增殖、分化和蛋白合成等过程中起重要作用.肺癌、哮喘、肺动脉高压、肺纤维化、慢性阻塞性肺疾病(chronic pulmonary obstructive disease,CORD)等疾病是呼吸系统常见疾病,其病理机制涉及细胞增殖及凋亡等,与PI3K/Akt/mTOR信号通路关系密切.     

Anti-apoptotic PTD-FNK protein suppresses lipopolysaccharide-induced acute lung injury in rats

The present study was aimed at clarifying the effects of an anti-apoptotic protein for modulating symptoms in acute lung injury (ALI). From Bcl-x(L), a Bcl-2 family member, we constructed an artificial protein (FNK) and fused it with the protein transduction domain (PTD) of the HIV/Tat protein (PTD-FNK) to facilitate its permeation into cells. ALI was induced by intratracheal infusion of lipopolysaccharide (LPS) into Sprague-Dawley male rats. PTD-FNK was injected into the peritoneal cavity of the animals either 2 h before, or 3 h or 6 h after LPS challenge. All rats were sacrificed 24 h after the last treatment. Cell differential ratios and albumin concentration were estimated in bronchoalveolar lavage fluid. We examined histological change, myeloperoxidase activity, TUNEL assay, caspase-3/caspase-3-like activity and immunohistochemical reaction for caspase 3 (active form). In animals with PTD-FNK treatment, the albumin leakage was significantly attenuated with protection of tissue damage. Also, the apoptosis of alveolar wall cells was reduced by PTD-FNK treatment, while a total cell number and the neutrophil ratio were not changed. Human umbilical vein endothelial cells (HUVEC) and cells of an alveolar epithelial cell line (A549) were exposed to LPS or TNF-alpha with or without PTD-FNK treatment in vitro. Cell survival rates examined by trypan-blue exclusion assay were increased by PTD-FNK treatment in a concentration-dependent manner. Thus, PTD-FNK could play a protective role in ALI by suppressing apoptosis of alveolar epithelial cells and capillary endothelial cells despite of some effect on neutrophil activity.     

PI3K/SGK1信号通路上调小鼠肺上皮钠通道表达的研究

目的:探讨磷酯酰肌醇3-激酶(PI3K)/血清-糖皮质激素调节激酶1(SGK1)信号通路对小鼠肺上皮钠通道(ENaC)表达的影响.方法:24只健康成年C3H/HeN小鼠随机分为对照组、急性肺损伤(ALI)组、胰岛素组和PI3K siRNA组,每组6只.收集支气管肺泡灌洗液(BALF),测量肺泡液体清除率(AFC),免疫...     

巨噬细胞PI3K/Akt通路与动脉粥样硬化的研究进展

动脉粥样硬化(AS)是冠心病的主要病理机制,巨噬细胞参与的免疫炎症反应伴随AS发生发展。PI3K/Akt通路可通过影响巨噬细胞极化、脂质代谢、自噬等多种功能参与AS调节进程,是AS治疗潜在靶点。本文将综述PI3K/Akt信号通路对巨噬细胞功能与AS调节作用的研究进展。     

Wortmannin,PI3K/Akt signaling pathway inhibitor,attenuates thyroid injury associated with severe acute pancreatitis in rats

Increasing evidences suggest that PI3K/AKT pathway plays an important role in the pathogenesis of inflammatory diseases such as acute pancreatitis. However, the exact effect of PI3K/AKT on thyroid injury associated with acute pancreatitis has not been investigated. This study aimed to investigate the protective effects of wortmannin, PI3K/AKT inhibitor, on thyroid injury in a rat model of severe acute pancreatitis (SAP). Sixty male SD rats were randomly divided into four groups: sham operating group (SO), SAP group, wortmannin treatment (WOR) group and drug control (WOR-CON) group. Serum amylase (AMY), lipase (LIP) and thyroid hormone levels were evaluated. The morphological change of thyroid tissue was analyzed under the light and transmission electron microscopy. AKT, P38MAPK and NF-κB expression in the thyroid tissue was evaluated by immunohistochemical staining. Oxidative stress and inflammatory cytokines were detected. Results showed that wortmannin attenuated the following: (1) serum AMY, LIP and thyroid hormone (2) pancreatic and thyroid pathological injuries (3) thyroid MDA, (4) thyroid ultrastructural change, (5) serum TNF-α, IL-6 and IL-1β (6) AKT, MAPKP38 and NF-κB expression in thyroid tissues. These results suggested that wortmannin attenuates thyroid injury in SAP rats, presumably because of its role on prevent ROS generation and inhibits the activation of P38MAPK, NF-κB pathway. Our findings provide new therapeutic targets for thyroid injury associated with SAP.     

过表达脑红蛋白通过激活PI3K/Akt信号通路防治AD的体外研究

 目的:探索过表达脑红蛋白（neuroglobin,NGB）对转染了pAPPswe的SH-SY5Y细胞的神经保护作用及机制。方法: 成功构建过表达NGB的质粒pEGFP-NGB并转染入已预先转染了pAPPswe的SH-SY5Y细胞,MTT法检测过表达NGB对该细胞存活率的影响;JC-1法检测其对细胞线粒体膜电位的影响;流式细胞术检测过表达NGB对细胞凋亡的影响;Western blotting法检测其对细胞中p-Akt、 Akt和caspase-3/9表达的影响;ELISA法检测其对细胞内Aβ42生成的影响。结果: MTT结果显示,与对照组和空质粒组比较,转染NGB后,pAPPswe-SH-SY5Y细胞的存活率明显提高,差异有统计学意义（P<0.05）。JC-1染色结果显示过表达NGB能够明显抑制转染pAPPswe对SH-SY5Y细胞线粒体膜电位的降低作用（P<0.05）。流式细胞术结果显示过表达NGB能够抑制早、晚期细胞的凋亡。而Western blotting显示过表达NGB不仅能抑制细胞内caspase-3和caspase-9蛋白水平的表达,而且还能够促进细胞内p-Akt蛋白的表达,而这种促进作用能够被PI3K/Akt的抑制剂LY294002所抑制。ELISA结果显示过表达NGB能够明显抑制细胞内Aβ42的生成。结论: 过表达NGB能够显著抑制pAPPswe诱导的细胞损伤,而且还抑制与细胞凋亡密切相关的caspase-3和caspase-9等蛋白表达。NGB的神经保护作用可能是通过激活PI3K/Akt信号通路来实现的。     

PI3K/Akt/mTOR信号转导通路与肿瘤

近年来,信号转导通路与肿瘤已成为了研究热点,而无论在生理还是病理条件下磷脂酰肌醇3激酶和哺乳动物雷帕霉素靶蛋白(PI3K/Akt/mTOR)信号转导通路在抑制凋亡、促进增殖方面都是一条重要的信号转导通路,并且PI3 K/Akt/mTOR信号传导通路在肿瘤治疗的研究中同样也发挥着重要作用.因而,研究PI3K/Akt/mTOR信号转导通路和主要组成部分以及PI3K、Akt、mTOR抑制剂具有重要意义.     

Differential roles of phosphatidylinositol 3-kinase/akt pathway in retinal ganglion cell survival in rats with or without acute ocular hypertension

Intraocular pressure (IOP) elevation has often been used as an experimental model to study mechanisms underlying retinal ganglion cell (RGC) death associated with ocular ischemic injury and glaucoma. The aim of the present study, using both in vitro and in vivo approaches, was to investigate the role of phosphatidylinositol 3-kinase (PI3K)/akt pathway in RGC viability in normal rats and rats following transient IOP elevation. For in vivo studies, pathway inhibitors were administered intravitreally on days 3, 9, and 15 post-2-h IOP elevation at 110 mm Hg. Toward the end of the 3-week examination period, the fluorescent dye Fluorogold was used to retrogradely label surviving RGCs. In order to examine the role of macrophages that were recruited into the eye following the pathway inhibition, clodronate liposomes were used to deplete phagocytic cells in the eye. PI3K/akt pathway activity and location in the retina were examined using Western blot and immunohistochemistry, respectively. Here we showed that PI3K/akt inhibitors 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002) and KY12420 at low concentrations (2 microM or 20 microM) did not influence RGC survival but caused RGC loss at high concentration (200 muM) in retinal explants derived from intact rats. In contrast, both LY294002 and KY12420 at 20 microM led to RGC loss in retinal explants derived from IOP-elevated eyes. A detrimental action of phagocytic cells on RGC survival was also seen in these retinas. In vivo results confirmed the detrimental actions of PI3K/akt inhibition and macrophages on RGC survival in IOP-elevated, but not intact eyes even with high concentration of LY294002. Low level of PI3K/akt activity was detected in the ganglion cell layer (GCL) in intact retina. Acute IOP elevation activated PI3K/akt pathway in the inner nuclear layer and GCL including RGCs. This study thus demonstrates that PI3K/akt pathway mediates RGC survival after IOP elevation but not under normal condition.