七氟烷通过P~(70S6K)/Nrf2信号通路诱导神经元HO-1mRNA表达

目的探讨七氟烷(Sevoflurane)诱导神经元血红素氧合酶-1(HO-1)基因表达的信号转导通路。方法将培养7d的新生大鼠海马神经元随机分为4组:正常培养组(C组)、2%七氟烷组(S1组)、4%七氟烷组(S2组)和4%七氟烷+Rapamycin组(R组)。C组神经元按正常培养方法培养。S1组和S2组神经元分别给予2%或4%七氟烷处理60min后继续培养24h。R组在神经元给予4%七氟烷处理同时在培养液中加入Rapamycin使其终浓度为10nmol.L-1后同S2组处理。收集神经元进行HO-1mRNA和P70S6K、Nrf2、AP-1和HO-1蛋白表达的检测。结果S1组P70S6K和Nrf2蛋白表达增加(vsC组,P<0.01),HO-1mRNA和HO-1蛋白表达增加(vsC组,P<0.01),AP-1蛋白表达变化不明显(vsC组,P>0.05)。S2组P70S6K和Nrf2蛋白表达增加(vsS1组,P<0.05),HO-1mRNA和HO-1蛋白表达增加(vsS1组,P<0.05),AP-1蛋白表达变化不明显(vsS1组,P>0.05)。R组P70S6K和Nrf2蛋白表达减少(vsS2组,P<0.01),HO-1mRNA和HO-1蛋白表达减少(vsS2组,P<0.01),AP-1蛋白表达变化不明显(vsS2组,P>0.05)。结论Sevoflurane通过P70S6K/Nrf2信号通路诱导神经元HO-1mRNA表达。     

脱氟烷通过ERK/P~(90RSK)信号通路诱导HO-1-mRNA表达抑制缺血/再灌注损伤神经元的凋亡

目的探讨脱氟烷(desflurane)的脑保护作用及其与神经元缺血/再灌注损伤后血红素氧合酶-1(HO-1)表达的信号转导通路的关系。方法将96孔和6孔培养板上培养7d的海马神经元随机分为7组:正常培养组(C组)、缺血/再灌注组(I/R组)、缺血/再灌注+6%desflurane组(D6组)、缺血/再灌注+12%desflurane组(D12组)、缺血/再灌注+12% desflurane+tin-protoporphyrin(HO-1抑制剂)组(T组)、缺血/再灌注+12% desflurane+U-0126(ERK抑制剂)组(U组)、缺血/再灌注+12% desflurane+rapamycin(RS6K抑制剂)组(R组)。C组神经元按正常培养方法培养。I/R组神经元进行缺糖缺氧后复糖复氧处理。D6组和D12组在神经元缺糖缺氧的同时接受6%或12%desflurane麻醉。T组、U组和R组在神经元进行缺糖同时分别加入tin-protoporphyrin、U-0126或Rapamycin使其终浓度均为10μmol·L-1后同D12组处理。96孔培养板的神经元进行细胞存活力的检测。6孔培养板的神经元进行神经元纯度鉴定、神经元凋亡、HO-1-mRNA表达、磷酸化ERK1/2和P90RSK蛋白表达的检测。结果缺血/再灌注后神经元存活率降低,凋亡率增加,HO-1-mRNA的表达增加,PERK1/2和PP90RSK蛋白表达增加(vsC组,P<0.01)。D6组PERK1/2和PP90RSK蛋白表达增加,HO-1-mRNA表达增加,神经元存活率增加、神经元凋亡率降低(vsI/R组,P<0.01)。D12组PERK1/2和PP90RSK蛋白表达增加,HO-1-mRNA表达增加,神经元存活率增加、神经元凋亡率降低(vsI/R组或D6组,P<0.01或P<0.05)。T组PERK1/2和PP90RSK蛋白表达变化不明显(vsD12组,P>0.05),HO-1-mRNA表达降低,神经元存活率降低、神经元凋亡率增加(vsD12组,P<0.01)。U组PERK1/2和PP90RSK表达降低,HO-1-mRNA表达降低,神经元存活率降低、神经元凋亡率增加(vsD12组,P<0.05或P<0.01)。R组PERK1/2蛋白表达变化不明显(vsD12组,P>0.05),PP90RSK表达降低,HO-1-mRNA表达降低,神经元存活率降低,神经元凋亡率增加(vsD12组,P<0.05或P<0.01)。结论Desflurane通过ERK1/2/P90RSK信号转导通路激活HO-1,在海马神经元缺血/再灌注时抑制了神经元凋亡,保护了神经元。     

氢吗啡酮预处理对大鼠肾缺血再灌注损伤时PI3 K/Akt的影响

目的 观察氢吗啡酮预处理对大鼠肾缺血再灌注损伤时PI3K/Akt的影响.方法 36只SD大鼠随机分为3组:假手术组(S组)、缺血再灌注组(IRI组)和氢吗啡酮预处理组(H组),每组12只.H组大鼠于造模前25 min腹腔注射氢吗啡酮30μg/kg,S组和IRI组注射等量生理盐水,采用夹闭双侧肾动脉制备缺血再灌注模型.H...     

七氟烷对肝脏缺血再灌注损伤的保护作用

肝脏缺血再灌注损伤(Hepatic ischemia reperfusion injury,HIRI)是许多病理过程以及肝脏外科手术中常见的病理生理过程,如出血性休克、肝叶切除术、肝脏移植等过程都可能发生肝脏缺血再灌注损伤.肝脏缺血再灌注损伤直接影响术后患者肝功能和肝脏再生能力,是术后肝功能异常、原发性移植肝无功能、多器官功能衰竭的重要原因,与术后肝功能衰竭的发生和患者死亡率的上升直接相关[1].因此,如何预防和减轻肝脏缺血再灌注损伤具有重要的临床意义.     

1-磷酸鞘氨醇对心肌缺血再灌注损伤所致细胞凋亡的影响及其与PI3K/Akt/GSK3β通路的相关性研究

目的 研究1-磷酸鞘氨醇（sphingosine 1-phosphate,S1P）对心肌缺血再灌注损伤（myocardial ischemia/reperfusioninjury,MIRI）所致细胞凋亡的影响及其与PI3K/Akt/GSK3β信号通路的相关性。方法 缺血30 min后,进行再灌注损伤120 min,建立大鼠MIRI模型。采用TTC染色方法测定心肌梗死面积,采用TUNEL染色方法观察心肌凋亡指数,采用酶联免疫方法测定血浆CK-MB活性。采用Western blot方法测定Akt、GSK3β磷酸化情况以及cleaved caspase-3水平,并测定细胞色素C释放情况。结果 S1P可明显减少心肌梗死面积、降低细胞凋亡指数。同时增加Akt、GSK3β磷酸化程度,降低cleaved caspase-3水平,减少胞浆细胞色素C易位。S1P的保护作用可被PI3K抑制剂LY294002所阻断。结论 S1P可通过抑制线粒体蛋白细胞色素C释放、减少caspase激活,减弱MIRI所致心肌细胞凋亡以及心肌梗死,该作用与PI3K/Akt/GSK3β信号通路活化有关。     

栀子苷对肝脏缺血再灌注损伤大鼠炎症反应、氧化应激和PI3K/Akt信号通路的影响

目的 探讨栀子苷对肝脏缺血再灌注损伤大鼠炎症反应、氧化应激和PI3K/Akt信号通路的影响。方法 将SD大鼠分为对照组、模型组和栀子苷5、10 mg/kg组,每组各10只。对照组、模型组大鼠ip溶剂橄榄油10 mg/kg,栀子苷5、10 mg/kg组大鼠ip栀子苷5、10 mg/kg,连续7 d,最后一次注射药物后进行肝缺血再灌注损伤建模处理。检测血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)、总胆红素、直接胆红素以及肿瘤坏死因子-α(TNF-α)、转化生长因子-β(TGF-β)、白细胞介素(IL)-6、IL-1β水平;测定肝组织丙二醛(MDA)、谷胱甘肽(GSH)、诱导型一氧化氮合酶(iNOS)、超氧化物歧化酶(SOD)水平;观察肝组织病理学变化和细胞凋亡;检测肝组织凋亡相关因子Bcl-2、Bax mRNA表达及p-PI3K、PI3K、p-Akt、Akt、Bcl-2、Bax、cleaved Caspase-3、Caspase-3蛋白表达。结果 与模型组相比,栀子苷5、10 mg/kg组血清ALT、AST、总胆红素、直接胆红素水平、TNF-α、TGF-β、IL-6、IL-1β、MDA和iNOS水平、肝组织凋亡细胞比例、Bax mRNA、蛋白表达和cleaved Caspase-3/Caspase-3显著降低(P<0.05),GSH、SOD水平、Bcl-2 mRNA和蛋白表达、p-PI3K/PI3K和p-Akt/Akt显著升高(P<0.05),且栀子苷10 mg/kg组作用效果更明显(P<0.05)。结论 栀子苷能够改善大鼠肝功能,减轻氧化应激、炎症反应和细胞凋亡,其作用机制可能是通过激活PI3K/Akt信号通路实现的。     

七氟烷后处理对大鼠缺血/再灌注损伤心功能和ERK1/2表达的影响

目的研究七氟烷后处理对细胞外信号调节激酶(ERK1/2)活性的影响,探讨其对大鼠离体心脏缺血/再灌注保护作用的机制。方法 (1)64只SD大鼠,随机分为8组(n=8):假手术组(Sham),缺血/再灌注组(Control),缺血后处理组(Post),七氟烷后处理组(Sevo),二甲基亚砜(PD98059溶剂)后处理组(DMSO),PD98059(ERK1/2抑制剂)后处理组(PD),缺血+PD98059后处理组(Post+PD),七氟烷+PD98059后处理组(Sevo+PD)。采用Langendorff离体心脏灌注模型,记录平衡灌注末,再灌注30、60、90 min心功能指标,灌注结束时,TTC法计算心肌梗死面积百分比。(2)48只SD大鼠,分组同上(n=6),复灌15 min,Westernblot法半定量测定心室胞质磷酸化ERK1/2(p-ERK1/2)及其下游靶点70 000核糖体S6蛋白激酶磷酸化(p-p70S6K)表达水平。结果平衡灌注末各组间心功能指标(基础值)差异无统计学意义(P>0.05)。Sevo组和Post组可改善缺血/再灌注心脏的各项心功能指标和减少心肌梗死面积(与Control组比较,P均<0.05)。复灌15 min时,Sevo组和Post组p-ERK1/2、p-p70S6K的表达高于Control组(P<0.05)。PD98059完全拮抗了七氟烷诱导的p-ERK1/2的表达同时抵消了其心肌保护效果。结论七氟烷后处理对大鼠离体心脏缺血/再灌注损伤有明显的保护作用,其保护强度与缺血后处理相当,机制可能与心肌细胞p-ERK1/2活性的增加有关。     

亚砷酸钠抑制PI3K/Akt 信号通路促进乳腺癌细胞凋亡的实验研究

目的　探讨亚砷酸钠促进乳腺癌细胞凋亡的作用及机制。方法　用不同浓度的亚砷酸钠分别作用于乳腺癌细胞（MCF-1/MDA-MB-231）48 h,MTT 法检测细胞增殖情况;用4 μg/mL的亚砷酸钠作用于乳腺癌细胞6 h、12 h、24 h、48 h 和72 h 后,MTT 法检测细胞增殖情况;同时采用流式细胞术检测细胞凋亡情况,Western blot 检测PI3K、p-PI3K、Akt 及p-Akt 的表达水平。结果　0.5 μg/mL、1 μg/mL、2 μg/mL、4 μg/mL、8 μg/mL亚砷酸钠作用48 h 后,MCF-1、MDAMB-231 细胞存活率均明显低于对照组（P<0.05）。MCF-1、MDA-MB-231 细胞经亚砷酸钠作用后细胞凋亡率明显高于对照组（P<0.01）。亚砷酸钠作用后的乳腺癌细胞中PI3K、Akt 的表达水平与对照组比较无显著差异（P>0.05）,而p-PI3K、p-Akt的表达水平明显低于对照组（P<0.01）。结论　亚砷酸钠可抑制乳腺癌细胞增殖,且其效应随作用时间的增加而增强;亚砷酸钠可促进乳腺癌细胞凋亡,其作用机制可能与抑制PI3K/Akt 信号通路的激活有关。     

七氟烷通过p38/Nrf2信号通路诱导HO-1基因表达抑制神经元凋亡

目的研究七氟烷诱导神经元血红素加氧酶1(HO-1)基因表达的信号转导通路,探讨七氟烷脑保护机制。方法将培养7d的新生Wistar大鼠海马神经元随机分为5组:正常培养组(C组)、氧糖剥夺组(D组)、2%七氟烷+氧糖剥夺组(S1组)、4%七氟烷+氧糖剥夺组(S2组)和4%七氟烷+SB203580+氧糖剥夺组(SB组)。C组神经元按正常培养方法培养。D组神经元进行缺糖、缺氧60min后复糖复氧后继续培养24h。S1组和S2组神经元分别给予2%或4%七氟烷预处理60min后同D组处理。SB组在神经元给予4%七氟烷处理同时在培养液中加入SB203580使其终浓度为10μmol/L后同S2组处理。收集神经元进行HO-1mRNA和p38、Nrf2、AP-1和HO-1蛋白表达的检测,检测神经元的存活率和凋亡率。结果与C组比较,D组神经元HO-1mRNA和HO-1蛋白表达增加(P<0.05),p38和Nrf2蛋白表达增加(P<0.05),AP-1蛋白表达表达增加(P<0.05),神经元存活率降低、凋亡率增加(P<0.01)。与D组比较,S1组神经元HO-1mRNA和HO-1蛋白表达增加(P<0.01),p38和Nrf2蛋白表达增加(P<0.01),AP-1蛋白表达表达变化不明显(P>0.05),神经元存活率升高、凋亡率降低(P<0.01)。与S1组比较,S2组神经元HO-1mRNA和HO-1蛋白表达增加(P<0.05),p38和Nrf2蛋白表达增加(P<0.05),AP-1蛋白表达表达变化不明显(P>0.05),神经元存活率升高、凋亡率降低(P<0.01)。与S2组比较,SB组神经元HO-1mRNA和HO-1蛋白表达降低(P<0.01),p38和Nrf2蛋白表达降低(P<0.01),AP-1蛋白表达表达变化不明显(P>0.05),神经元存活率降低、凋亡率升高(P<0.01)。结论七氟烷通过p38/Nrf2信号通路诱导神经元HO-1mRNA表达,抑制氧糖剥夺神经元的凋亡。     

玉郎伞查尔酮调控PI3K/Akt信号通路抗心肌缺血/再灌注损伤的作用及机制研究

目的探讨玉郎伞查尔酮(YLSC)调控PI3K/Akt信号通路抗心肌缺血/再灌注损伤的作用及机制。方法 40只♂SD大鼠随机分为5组:假手术组、模型组、YLSC组、YLSC+PI3K抑制剂wortmannin组(YLSC+WM组)、PI3K抑制剂wortmannin组(WM组),每组8只。除假手术组外,其它各组大鼠均结扎冠状动脉左前降支制备心肌缺血模型,缺血30 min,再灌注120 min。实验结束后,采用比色法测定大鼠血清中肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH)及一氧化氮(NO)水平,ELISA法测定血清肿瘤坏死因子(TNF-α)的含量,Western blot法检测心肌组织中总Akt(t-Akt)、磷酸化Akt(p-Akt)及自噬相关蛋白LC3-Ⅱ的表达,FQ-PCR法分析内皮型一氧化氮合酶(eN OS)、凋亡因子caspase-3及自噬相关基因Beclin1的表达量变化。结果与I/R组比较,YLSC组CK-MB、LDH以及TNF-α血清含量明显降低,NO水平升高,Beclin1、caspase-3及LC3-Ⅱ的表达量均明显下降,同时Akt的磷酸化水平与eN OS mR NA表达增加,上述各项指标差异具有统计学意义(P<0.05),而上述变化能够被PI3K/Akt信号通路的特异性阻断剂wortmannin所阻断,且其差异具有统计学意义(P<0.05)。结论 YLSC通过激活PI3K/Akt信号通路抑制缺血/再灌注所致的心肌细胞凋亡和过度自噬,从而发挥对心肌缺血/再灌注损伤的保护作用。     

淀粉样β蛋白片段25~35下调大鼠海马PI3K/Akt/p70S6K信号传导通路(英文)

目的探讨阿尔茨海默病(AD)的淀粉样β蛋白(Aβ)的沉积是否损害神经细胞存活的信号传导通路。方法实验分为生理盐水对照组;Aβ25-35组;Aβ25-35+布洛芬组;Aβ25-35+布洛芬+LY294002组;Aβ25-35+LY294002组。大鼠分别灌胃给予布洛芬7.5或15 mg.kg-1,每日1次,连续3周后,左侧脑室内注射Aβ25-35(10 μL, 1 mmol.L-1),之后继续灌胃给予布洛芬1周。PI3K特异性阻断剂LY294002 (5 μL, 4 mmol.L-1)在注射Aβ25 -35前1 h左侧脑室内注射。注射Aβ25-35后1周,取海马CA1区,Western免疫印迹法观察P53,Bax, FasL, Bcl-2, Akt和p70S6K的蛋白表达水平。应用半胱氨酸天冬氨酸蛋白酶(caspase)3活性测定试剂盒分析caspase 3活性变化,RT-PCR方法观察p70s6k mRNA表达水平。结果脑室内注射Aβ25-35可引起大鼠海马CA1区磷酸化Akt/PKB和磷酸化p70S6K表达明显降低,分别从对照组1.32±0.14和0.769±0.028下降到0.69±0.08和0.479±0.032。同时,海马CA1区促凋亡蛋白P53, Bax和FasL表达及caspase 3活性明显增加,抗凋亡蛋白Bcl-2表达明显降低。预先注射LY294002可使caspase 3活性较单独注射Aβ25-35组进一步增加。给Aβ25-35前后连续给予布洛芬4周可明显对抗Aβ25-35引起的上述变化。LY294002可明显减弱布洛芬上调磷酸化Akt/PKB和磷酸化p70S6K表达的作用。结论 Aβ25-35引起抗凋亡通路PI3K/Akt/p70S6K下调可能参与AD的神经元损伤。布洛芬具有较好的对抗作用,这可能与上调PI3K/Akt/p70S6K通路中的一些蛋白有关。     

淀粉样β蛋白片段25～35下调大鼠海马PI3K/Akt/p70S6K信号传导通路

目的 探讨阿尔茨海默病（AD）的淀粉样β蛋白(Aβ)的沉积是否损害神经细胞存活的信号传导通路。方法 实验分为生理盐水对照组；Aβ_25-35组；Aβ_25-35 +布洛芬组；Aβ_25-35+布洛芬+LY294002组；Aβ_25-35+LY294002组。大鼠分别灌胃给予布洛芬7.5或15 mg·kg^-1，每日1次，连续3周后，左侧脑室内注射Aβ_25-35（10 μL, 1 mmol·L^-1，之后继续灌胃给予布洛芬1周。PI3K特异性阻断剂LY294002（5 μL, 4 mmol·L^-1在注射Aβ_25-35前1 h左侧脑室内注射。注射Aβ_25-35后1周，取海马CA1区，Western免疫印迹法观察P53, Bax, FasL, Bcl-2, Akt和p70S6K的蛋白表达水平。应用半胱氨酸天冬氨酸蛋白酶(caspase)3活性测定试剂盒分析caspase 3活性变化，RT-PCR方法观察p70s6k mRNA表达水平。结果 脑室内注射Aβ_25-35可引起大鼠海马CA1区磷酸化Akt/PKB和磷酸化p70S6K表达明显降低，分别从对照组1.32±0.14和0.769±0.028下降到0.69±0.08和0.479±0.032。同时,海马CA1区促凋亡蛋白P53, Bax和FasL表达及caspase 3活性明显增加，抗凋亡蛋白Bcl-2表达明显降低。预先注射LY294002可使caspase 3活性较单独注射Aβ_25-35组进一步增加。给Aβ_25-35前后连续给予布洛芬4周可明显对抗Aβ_25-35引起的上述变化。LY294002可明显减弱布洛芬上调磷酸化Akt/PKB和磷酸化p70S6K表达的作用。结论 Aβ_25-35引起抗凋亡通路PI3K/Akt/p70S6K下调可能参与AD的神经元损伤。布洛芬具有较好的对抗作用，这可能与上调PI3K/Akt/p70S6K通路中的一些蛋白有关。     

Overexpressed Hsp70 alleviated formaldehyde‐induced apoptosis partly via PI3K/Akt signaling pathway in human bronchial epithelial cells

Formaldehyde (FA) is a ubiquitous environmental pollutant, which can induce apoptosis in lung cell and is related to the pathogenesis of asthma, pneumonia, and chronic obstructive pulmonary disease. Heat shock protein 70 (Hsp70) is an ATP‐dependent molecular chaperone and exhibits an anti‐apoptosis ability in a variety of cells. Previous studies reported that the expression of Hsp70 was induced when organisms were exposed to FA. Whether Hsp70 plays a role in the FA‐induced apoptosis and the involved cell signaling pathway remain largely unknown. In this study, human bronchial epithelial cells with overexpressed Hsp70 and the control were exposed to different concentrations of FA (0, 40, 80, and 160 μmol/L) for 24 hours. Apoptosis and the expression levels of PI3K, Akt, p‐Akt, MEK, p‐MEK, and GLI2 were detected by Annexin‐APC/7AAD double‐labeled flow cytometry and western blot. The results showed that overexpression of Hsp70 decreased the apoptosis induced by FA and alleviated the decline of PI3k and p‐Akt significantly. Inhibitor (LY 294002, a specific inhibitor of PI3K‐Akt) test result indicated that PI3K‐Akt signaling pathway was involved in the inhibition of FA‐induced apoptosis by Hsp70 overexpression and also active in the maintenance of GLI2 level. However, it also suggested that other signaling pathways activated by overexpressed Hsp70 participated in this process, which was needed to be elucidated in further research.     

Sodium tanshinone IIA sulfonate protects rat myocardium against ischemia-reperfusion injury via activation of PI3K/Akt/FOXO3A/Bim pathway

Aim： To investigate the mechanisms underlying the protective effects of sodium tanshinone IIA sulfonate （STS） in an ischemia- reperfusion （I/R）-induced rat myocardial injury model. Methods： Male SD rats were iv injected with STS, STS＋LY294002, or saline （NS） for 15 d. Then the hearts were subjected to 30 min of global ischemia followed by 2 h of reperfusion. Cardiac function, infarction size and area at risk were assessed. Cell apoptosis was evaluated with TUNEL staining, DNA laddering and measuring caspase-3 activity. In addition, isolated cardiomyocytes of neonatal rats were pretreated with the above drugs, then exposed to H202 （200 μmol/L） for I h. Cell apoptosis was detected using flow cytometric assay. The levels of p-Akt, p-FOXO3A and Bim were examined with immunoblotting. Results： Compared to NS group, administration of STS （20 mg/kg） significantly reduced myocardial infarct size （40.28%＋5.36% in STS group vs 59.52%±7.28% in NS group）, and improved the myocardial function as demonstrated by the increased values of dp/dt LVDP and coronary flow at different reperfusion time stages. Furthermore, STS significantly decreased the rate of apoptotic cells （15.11%±3.71% in STS group vs 38.21%±7.83% in NS group）, and reduced caspase-3 activity to nearly a quarter of that in NS group. Moreover, STS significantly increased the phosphorylation of Akt and its downstream target FOXO3A, and decreased the expression of pro-apoptotic gene Bim. Co-treatment with the PI3K inhibitor LY294002 （40 mg/kg） partially countered the protective effects induced by STS treatment. In isolated cardiomyocytes, STS exerted similar protective effects as shown in the ex vivo I/R model. Conclusion： STS pretreatment reduces infarct size and improves cardiac function in an I/R-induced rat myocardial injury model via activation of Akt/FOXO3A/Bim-mediated signal pathway.     

Targeting MAPK (Ras/ERK) and PI3K/Akt pathways in pituitary tumorigenesis

Background: Pituitary adenomas are common intracranial neoplasms, comprising 10 – 15% of all brain tumors. Data from autopsy studies suggest that pituitary adenomas develop in 17 – 25% of the population. Nevertheless, the pathogenesis of sporadic pituitary tumors still remains obscure. Objective: In this review, the roles of MAPK (mainly Ras/extracellular signal-regulated protein kinase (ERK)) and PI3K/Akt signaling pathways in pituitary tumorigenesis are summarised. Methods: A full data search was performed through PubMed over the years 2000 – 2009 with key words ‘pituitary, pituitary tumor, molecular biology, Akt, MAPK, PI3K, ERK’, and all relevant publications have been included, together with selected publications prior to that date. Growth factor receptor mutations and overexpression, G protein mutations, other signaling pathway abnormalities or genetic syndromes associated with pituitary tumors are not discussed as these topics are behind the scope of this review. Conclusions: There are preclinical data and human pituitary tumor studies that are compatible with increased Ras/ERK and/or PI3K/Akt pathway activity in pituitary tumors. Future research focusing on scaffold proteins and signaling modulators regulating these pathways may help identify the initiating transforming events and accordingly new strategies may be developed targeting these pathways in pituitary tumors.     

Salidroside exerts angiogenic and cytoprotective effects on human bone marrowderived endothelial progenitor cells via Akt/mTOR/p70S6K and MAPK signalling pathways

Background and Purpose

With the increase of age, increased susceptibility to apoptosis and senescence may contribute to proliferative and functional impairment of endothelial progenitor cells (EPCs). The aim of this study was to investigate whether salidroside (SAL) can induce angiogenic differentiation and inhibit oxidative stress-induced apoptosis in bone marrow-derived EPCs (BM-EPCs), and if so, through what mechanism.

Experimental Approach

BM-EPCs were isolated and treated with different concentrations of SAL for up to 4 days. Cell proliferation, migration and tube formation ability were detected by DNA content quantification, transwell assay and Matrigel-based angiogenesis assay. Gene and protein expression were assessed by qRT-PCR and Western blot respectively.

Key Results

Treatment with SAL promoted cellular proliferation and angiogenic differentiation of BM-EPCs, and increased VEGF and NO secretion, which in turn mediated the enhanced angiogenic differentiation of BM-EPCs. Furthermore, SAL significantly attenuated hydrogen peroxide (H₂O₂)-induced cell apoptosis, reduced the intracellular level of reactive oxygen species and restored the mitochondrial membrane potential of BM-EPCs. Moreover, SAL stimulated the phosphorylation of Akt, mammalian target of rapamycin and p70 S6 kinase, as well as ERK1/2, which is associated with cell migration and capillary tube formation. Additionally, SAL reversed the phosphorylation of JNK and p38 MAPK induced by H₂O₂ and suppressed the changes in the Bax/Bcl-xL ratio observed after stimulation with H₂O₂.

Conclusions and Implications

These findings identify novel mechanisms that regulate EPC function and suggest that SAL has therapeutic potential as a new agent to enhance vasculogenesis as well as protect against oxidative endothelial injury.     

Resveratrol attenuates intestinal injury in irradiated rats via PI3K/Akt/mTOR signaling pathway

Radiation‐induced enteritis is one of the greatest challenges in radiotherapy. The current study was designed to evaluate the ameliorative effect of resveratrol, which exhibits anti‐inflammatory property, against radiation‐induced intestinal injury in rats and to explore the underlying mechanism. Rats were exposed to a single dose of 5 Gy. Resveratrol (20 mg/kg/day) was orally administered to irradiated rats over 3 weeks. Results showed that resveratrol ameliorated the intestinal oxidative stress parameters; malondialdehyde (MDA) content, glutathione (GSH) level, and catalase (CAT) activity compared to irradiated group. Furthermore, resveratrol reduced the contents of inflammatory cytokines; tumor necrosis factor α (TNF‐α), nuclear factor‐kappa (NF‐κB), and interleukin 1β (IL‐1β) in intestine. Western blotting analysis revealed that resveratrol down‐regulated the proteins expression of phosphoinositide 3‐kinases (PI3K), protein kinase B (Akt) as well as the mammalian target of rapamycin (mTOR) in intestinal tissues of irradiated rats and thus reduced the inflammatory mediator production. These results were confirmed by histopathological investigation. In conclusion, resveratrol attenuated intestinal inflammation following irradiation via modulating PI3K/Akt/mTOR pathway and thereby could be a promising adjuvant in radiotherapy.     

PI3K/Akt/mTOR信号传导通路与前列腺癌关系的研究进展

前列腺癌是威胁中老年男性健康的常见肿瘤,成为男性癌症死因的第二位。 PI3K/Akt/mTOR信号通路能够通过维持细胞生存、抑制细胞凋亡、促进细胞周期运行及血管生成等促进前列腺癌病程发展。本文综合国内外文献,阐述PI3K/Akt/mTOR信号通路在前列腺癌发生发展中的作用以及和通路相关的药物治疗进展。     

Dexmedetomidine protects mice against myocardium ischaemic/reperfusion injury by activating an AMPK/PI3K/Akt/eNOS pathway

Acute myocardial ischaemia/reperfusion (MIR) injury leads to severe arrhythmias and has a high rate of lethality. In the present study, we aim to determine the effect of dexmedetomidine (Dex) on heart injury parameters following MIR surgery. We examined the effects of Dex on heart function parameters and infarct size following MIR surgery. Proinflammatory cytokines, oxidative products and anti‐oxidative enzymes in the myocardium were measured to evaluate the anti‐inflammatory and anti‐oxidative effects of Dex. The role of the adenosine 5′‐monophosphate (AMP)‐activated protein kinase (AMPK)/phosphatidylino‐sitol 3‐kinase (PI3k)/Akt/endothelial nitric oxide synthase (eNOS) pathway was investigated using their inhibitors. The alteration of haemodynamic parameters, histopathological results, and infarct size caused by MIR was attenuated by Dex. The interleukine‐1 beta (IL‐1β), IL‐6, tumour necrosis factor‐a (TNF‐α) and myeloperoxidase (MPO) were all significantly decreased. Anti‐oxidative enzymes superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) were restored by Dex. Oxidative products8‐OHdG, MDA and protein carbonyl were all decreased by Dex (P<.05). Dex activated AMPK expression, eNOS and Akt phosphorylation. The influence of Dex on cardiac function was reversed by the inhibitors of the eNOS, AMPK and PI3K/Akt pathways. These results indicate that Dex protected the cardiac functional, histological changes, inflammation and oxidative stress induced by MIR. Our results present a novel signalling mechanism that Dex protects MIR injury by activating an AMPK/PI3K/Akt/eNOS pathway.