牛膝活性成分β-蜕皮甾酮通过Akt信号干预地塞米松诱导的骨细胞凋亡

目的探讨牛膝活性成分β-蜕皮甾酮对地塞米松诱导MLO-Y4骨样细胞凋亡的抑制作用及其可能的作用机制。方法 10μmol/L地塞米松(dexamethasone,Dex)作用于MLO-Y4骨样细胞,以PI3K/Akt抑制剂LY294002为对照,β-蜕皮甾酮(β-Ecdysone,β-Ecd)干预,分为6组:①正常组;②10μmol/L Dex模型组;③10μmol/L Dex+10μmol/Lβ-Ecd组;④10μmol/L Dex+10μmol/Lβ-Ecd+50μmol/L LY294002组;⑤10μmol/L Dex+0.1μmol/Lβ-Ecd组;⑥10μmol/L Dex+0.1μmol/Lβ-Ecd+50μmol/L LY294002组。作用48 h后,Annexin V-FITC/PI法检测细胞早期凋亡率,Western-Blot检测Akt1、Phospho-Akt(Thr308)、Connexin43(CX43)、Caspase9、Bad、Phospho-Bad蛋白表达。结果与正常组比较,Dex组细胞凋亡率升高,Caspase9、Bad蛋白表达升高,Akt1、CX43蛋白表达降低;与造模组比较,β-Ecd减弱Caspase9蛋白表达,使Akt1、CX43蛋白表达增强;LY294002使Akt1、CX43蛋白表达明显减弱,而β-Ecd并不能使LY294002降低的Akt1蛋白表达升高。结论 0.1μmol/L、10μmol/Lβ-蜕皮甾酮可能通过Akt信号途径干预地塞米松诱导的骨细胞凋亡。     

柚苷对髓核间充质干细胞生物学性能的影响及其相关机制

目的:探讨柚苷对人退变腰椎间盘来源髓核间充质干细胞(human nucleus pulposus-derived mesenchymal stem cell,h NPMSC)生物学性能的影响及其可能机制。方法:收集腰椎间盘突出症患者的退变髓核组织,分离培养h NPMSC并进行体外扩增。通过细胞形态学观察、细胞免疫表型检测及三系分化进行间充质干细胞的鉴定。取P3代hNPMSC分为对照组(正常培养基培养)、柚苷组(以含20μg/mL柚苷的培养基培养)和LY294002组(用含20μg/mL柚苷及PI3K/Akt信号通路抑制剂LY294002的培养基培养),培养6d后通过流式细胞仪检测细胞凋亡率,TUNEL荧光检测TUNEL染色阳性细胞率,Western Blot检测凋亡相关蛋白Caspase-3、Bcl-2和Bax及PI3K/Akt信号通路相关蛋白p-Akt、Akt和p53的表达,RT-PCR检测Ⅱ型胶原及蛋白多糖的m RNA表达。结果:来自人退变腰椎间盘髓核的原代细胞贴壁生长,呈不规则多边形,传代后以梭形为主;高表达干细胞相关阳性表面抗原分子CD73、CD90及CD105,低表达CD45及CD34;茜素红染色、油红O染色及甲苯胺蓝染色证实经诱导后可向骨、脂肪及软骨细胞分化,符合间充质干细胞的表型。与对照组比较,柚苷组细胞凋亡率、TUNEL染色阳性细胞率、p53、Caspase-3和Bax蛋白表达显著性下降,p-Akt及抗凋亡蛋白Bcl-2表达显著性增加(P0.05);LY294002干预后可以逆转这种改变(P0.05)。与对照组比较,柚苷组hNPMSC中Ⅱ型胶原及蛋白多糖的m RNA表达显著性增加;LY294002组中Ⅱ型胶原及蛋白多糖的m RNA表达较柚苷组显著性减少(P0.05)。结论:柚苷可通过激活PI3K/Akt信号通路减少细胞凋亡,促进hNPMSC向髓核细胞分化。     

MEK/ERK信号通路在吡咯喹啉醌促雪旺细胞增殖中的作用

目的 探讨MEK/ERK信号通路在吡咯喹啉醌促雪旺细胞增殖过程中的作用. 方法 体外培养雪旺细胞,S-100免疫荧光鉴定;Western blot检测MEK下游因子ERK1/2磷酸化激活形式(p-ERK1/2)的表达;MEK抑制剂(PD98059)阻断该通路后检测p-ERK1/2的表达;MTT法检测经PD98059阻断MEK通路后雪旺细胞的增殖情况. 结果 吡咯喹啉醌可激活雪旺细胞内MEK/ERK信号通路,在加入吡咯喹啉醌1 h后p-ERK1/2表达最高;吡咯喹啉醌在1～500 nmol/L范围内可使p-ERK1/2表达增加,1 000 nmol/L时与对照组比较差异无统计学意义,10 000 nmol/L时则表现为抑制作用(P＜0.05);经PD98059阻断MEK通路后p-ERK1/2的上调效应消失(P＜0.05).而且加入PD98059阻断MEK通路后吡咯喹啉醌对雪旺细胞的促增殖效果减弱. 结论 吡咯喹啉醌可激活雪旺细胞MEK/ERK信号通路,且该通路在吡咯喹啉醌促雪旺细胞增殖过程中发挥作用.     

LY294002对胆管癌细胞凋亡的影响

目的：观察PI3-Kinase抑制剂LY294002对人胆管癌细胞QBC939的作用。
方法：MTT法检测LY294002对QBC939细胞的生长抑制作用;流式细胞术检测LY294002诱导的细胞凋亡;免疫印迹法分析LY294002对于PI3-K/Akt信号通路中Akt磷酸化及caspase9的表达作用。
结果：LY294002可抑制胆管癌细胞QBC939的增殖,促进其凋亡。Western-blotting显示,LY2940022可抑制Akt磷酸化水平,促进caspase3,9的蛋白表达。
结论：LY294002可通过抑制Akt信号通路的活性,上调促凋亡分子caspase3,9的表达,抑制胆管癌细胞QBC939的增殖,诱导其凋亡。

     

乳化异氟醚预处理对大鼠局灶性脑缺血再灌注时海马CA1区神经元凋亡的影响

目的 评价乳化异氟醚预处理对大鼠局灶性脑缺血再灌注时海马CA1区神经元凋亡的影响.方法 健康成年雄性SD大鼠48只,体重250～300 g,月龄4～6月,采用随机数字表法,将大鼠随机分为6组(n=8),假手术组(S组)腹腔注射生理盐水10.5 ml/kg,24 h后只分离血管,不置入线栓;缺血再灌注组(I/R组)和乳化异氟醚预处理组(EI组)分别腹腔注射生理盐水或8%乳化异氟醚10.5 ml/kg(120 mg/ml);LY294002+乳化异氟醚预处理组(L+EI组)缺血侧侧脑室注射LY294002(磷脂酰肌醇-3激酶特异性抑制剂)25 mmol/L 5 μl,30 min后腹腔注射8%乳化异氟醚10.5 ml/kg;LY294002组(L组)和DMSO(LY294002溶剂)组缺血侧侧脑室注射LY294002 25 mmol/L(5 μl)或DMSO 5 μl.于给 药后24 h采用大脑中动脉缺血2 h恢复再灌注的方法制备局灶性脑缺血再灌注模型.于再灌注24 h时行神经功能缺陷评分,检测海马CA1区神经元凋亡情况和磷酸化丝氨酸-苏氨酸蛋白激酶(p-Akt)表达,观察海马CA1区病理学改变.结果 与S组比较,其余各组神经功能缺陷评分、凋亡细胞计数升高.p-Akt表达上调(P＜0.05);与I/R组比较,EI组神经功能缺陷评分、凋亡细胞计数降低,p-Akt表达上调(P＜0.05),L+EI组、L组、DMSO组上述各指标差异无统计学意义(P＞0.05);与EI组比较,L+EI组神经功能缺陷评分、凋亡细胞计数升高,p-Akt表达下调(P＜0.05).EI组病理学损伤程度明显轻于I/R组,L+EI组、L组、DMSO组与I/R组相似.结论 乳化异氟醚预处理可减少大鼠局灶性脑缺血再灌注时海马CA1区神经元凋亡,其神经元保护作用与PI3K/Akt通路激活有关.

Abstract：

Objective To investigate the effect of preconditioning with emulsified isoflurane (eISO) on neuronal apoptosis in hippocampal CA1 region induced by focal cerebral ischemia-reperfusion (I/R) injury in rats. Methods Forty-eight healthy adult male SD rats weighing 250-300 g were randomly divided into 6 groups (n = 8 each): sham operation group (group S); I/R group; eISO + I/R group (group EI); LY294002 (a specific PI3K inhibitor) + eISO + I/R group (group L+ EI); LY294002 + I/R group (group L) and DMSO (solvent for LY294002) + I/R group (group DMSO). Focal cerebral I/R was induced by 2 h middle cerebral artery occlusion ( MCAO). A nylon thread (0.26 mm in diameter) with rounded tip was inserted into internal carotid artery and advanced cranially until resistance was met (depth of insertion about 18-20 mm) . eISO 10.5 ml/kg (120 mg/ml) was injected intraperitoneally (IP) in groups EI and L+ EI. LY294002 (25 mmol/L) 5 pi was injected into cerebral ventricle on the ischemic side in group L + EI ( at 30 min before eISO) and group L. DMSO 5 μl was injected into the cerebral ventricle on ischemic side before MCAO in group DMSO. Neurologic deficit was assessed and scored (0 = normal, 4 = unconscious) at 24 h of reperfusion. The animals were then killed and their brains were removed for detection of neuronal apoptosis (by TUNEL) and p-Akt expression (by immuno-histochemistry) in hippocampal CA1 region. Results Cerebral I/R significantly increased the neurologic deficit scores, the number of apoptotic cells and p-Akt expression in group I/R as compared with group S. Preconditioning with elSO attenuated the I/R-induced increase in neurologic deficit scores and number of apoptotic cells but further increased p-Akt expression. The neuroprotective effect of eISO preconditioning against I/R-induced changes was counteracted by LY294002. Conclusion eISO preconditioning can attenuate focal cerebral I/R-induced neuronal apoptosis in rats by activating PI3K/Akt pathway.     

热损伤诱导的丝裂原活化蛋白激酶对活化蛋白-1的影响及其意义

目的 观察成纤维细胞热烫伤后丝裂原活化蛋白激酶以及活化蛋白-1的表达。方法 将培养的人成纤维细胞分成4组：(1)单纯热损伤刺激组；(2)热损伤刺激 碱性成纤维细胞生长因子处理组(10μg／L)；(3)预先加入PD98059(10μmoL/L)，再行热损伤 碱性成纤维细胞生长因子(bFGF)刺激；(4)预先加入PD98059 SB203580(各10μmol／L)阻断剂30min，再行热损伤 碱性成纤维细胞生长因子刺激。伤后0、30、60和180min检测细胞外信号调节激酶(ERK)和原癌基因c-fos蛋白。结果单纯热刺激的成纤维细胞ERK表达增加，随后消失。碱性成纤维细胞生长因子刺激ERK表达增加显著，时间延长。加入PD98059拮抗剂，ERK的表达受抑制。原癌基因c-fos的表达开始增加，随后减弱。同时阻断ERK和p38MAPK两条通路，c-fos弱阳性表达。结论 碱性成纤维细胞生长因子引起热损伤成纤维细胞ERK表达增加，原癌基因c-fos是MAPK信号通路下游重要的靶蛋白。     

紫草素调控PI3K/Akt/mTOR通路对人胃癌MGC803细胞自噬和凋亡的影响

目的：研究紫草素对人胃癌MGC803细胞自噬和凋亡的影响及作用机制。方法 ：取对数生长期MGC803细胞,设空白对照组、紫草素组、紫草素+IGF-1(PI3K激活剂)组、紫草素+LY294002(PI3K抑制剂)组。药物干预24 h后,CCK-8法检测细胞增殖抑制率,流式细胞术检测细胞凋亡,GFP-LC3质粒转染法观察细胞自噬小体,Western blot法检测磷脂酰肌醇3激酶（PI3K）、p-PI3K、蛋白激酶B(Akt)、p-Akt、哺乳动物雷帕霉素靶蛋白（mTOR）、p-mTOR、Caspase-3、cleaved Caspase-3、LC3、Beclin-1的表达。结果：与空白对照组比较,紫草素组细胞增殖抑制率、凋亡率升高（P<0.05）,自噬小体数量明显增多,PI3K、Akt、mTOR磷酸化水平降低（P<0.05）,cleaved Caspase-3/Caspase-3、LC3-Ⅱ/LC3-Ⅰ及Beclin-1表达量升高（P<0.05）。IGF-1可明显逆转紫草素对MGC803细胞增殖抑制、凋亡、自噬,PI3K、Akt、mTOR磷酸化和cleaved Cas...     

姜黄素与LY294002联合应用对前列腺癌PC-3细胞体外生长的影响

【摘要】 目的〓探讨姜黄素与PI3K/Akt抑制剂LY294002联合应用对前列腺癌PC-3细胞体外生长的影响。方法〓根据给药不同将实验分为对照组、姜黄素组、LY294002组和姜黄素组+LY294002联合组,分别加入等量的培养基、25 μmoL/L姜黄素、25 μmoL/L的LY294002和两种混合液。采用MTS法检测各组细胞的增殖情况、流式细胞仪术检测各组细胞凋亡情况、q-PCR测定各组细胞中NF-κB、P53及caspase-9的表达情况。结果〓姜黄素组、LY组和联合组的细胞增值率均较对照组明显降低,且联合组明显低于两个单独用药组(P<0.05)。姜黄素与LY294002联合作用前列腺癌PC-3细胞后,细胞总凋亡率较姜黄素及LY294002单独使用后明显增加(P值均<0.05)。联合用药组的NF-κB表达量明显低于两单独用药组(P<0.05),而P53和caspase-9的表达量均明显高于两单独用药组(P<0.05)。结论〓姜黄素与LY294002联合使用较两种药物单独使用更能有效抑制前列腺癌PC-3细胞的体外生长,作用机制可能是通过抑制NF-κB的表达从而抑制细胞增殖,并增加P53和caspase-9的表达从而促进细胞凋亡来实现的。     

胰岛素样生长因子1对结肠癌细胞凋亡的影响及其机制研究

目的研究胰岛素样生长因子1(IGF-I)通过磷酯酰肌醇3-激酶/蛋白激酶B(PI-3K/Akt)信号通路对结肠癌细胞株SW480凋亡率的影响及凋亡抑制蛋白survivin表达水平的变化。方法在培养结肠癌SW480细胞株时,采用不同浓度的IGF-I不同时间作用于SW480细胞,然后采用Western blot检测凋亡抑制蛋白survivin表达变化。100 ng/mL IGF-I作用于SW480细胞2 h内,Westernblot检测Akt的磷酸化表达变化;Akt特异性抑制剂LY294002处理前后,利用Western blot检测Akt磷酸化表达的变化,Western blot及细胞免疫荧光检测survivin表达的变化,流式细胞术检测细胞凋亡率的改变。结果IGF-I能上调SW480细胞的survivin表达,且其表达水平与IGF-I的作用时间、浓度呈依赖性(IGF-I作用SW480细胞不同时间后,survivin蛋白表达显著升高,并在12 h时达到峰值,所有实验组survivin蛋白的表达均显著高于对照组;IGF-I浓度为100 ng/mL时,survivin蛋白的表达达到顶峰);IGF-I快速激活SW480细胞中PI-3K/Akt信号通路(IGF-I作用SW480细胞15,30 min后,p-Akt蛋白的表达达到高峰);IGF-I能通过PI-3K/Akt信号通路上调SW480细胞survivin的表达;IGF-I能通过PI-3K/Akt信号通路抑制SW480细胞凋亡[利用流式细胞术检测空白组、刺激组、阻断组各组SW480细胞的凋亡率,分别为(5.18±0.415)%,(0.85±0.052)%,(3.15±0.411)%,各组之间差异有统计学意义(P0.05)]。结论IGF-I可通过PI-3K/Akt通路诱导survivin表达,从而抑制结肠癌细胞SW480的凋亡。     

毛蕊异黄酮对PI3K/Akt信号通路与PC-3细胞凋亡的作用

目的 探究毛蕊异黄酮促进前列腺癌细胞PC-3凋亡的机制.方法 选取0、25、50、100、200μmol/L的毛蕊异黄酮(Calycosin)处理PC-3细胞,并设置溶剂对照(DMSO,二甲基亚砜)组,采用MTT法检测48h后细胞增殖情况;流式细胞术检测0、25、50、100、200 μmol/L48h后细胞凋亡率;Western Blot法检测0μmoL/L组、200μmol/L毛蕊异黄酮组、200μmol/L毛蕊异黄酮+ PI3K特异性抑制剂(Wortmannin)共处理组细胞的Akt、磷酸化的Akt(p-Akt)、Bax、Bcl-2和Caspase-3蛋白的表达水平.结果 MTT实验显示毛蕊异黄酮能够抑制PC-3细胞的增殖,且呈现剂量依赖性(P＜0.05);流式细胞实验显示,0、25、50、100、200μmol/L浓度水平的毛蕊异黄酮处理PC-3细胞48h后的凋亡率分别为(0.1±0.04)％、(6.8±0.6)％、(9.2±0.2)％、(11.5±0.27)％、(59.2±0.36)％(P ＜0.05);Western blot法显示,与0μmol/L组相比,200μmol/L毛蕊异黄酮组p-Akt、Bcl-2表达水平下降(P＜0.05),加入Wortmannin后,二者水平再次下降;与0μmol/L组相比,200μmol/L毛蕊异黄酮组Bax、Caspsse-3表达水平增加(P＜0.05),加入Wortmannin后,二者水平再次增加.结论 毛蕊异黄酮可抑制PC-3细胞的增殖并诱导其凋亡,其机制是下调PI3K/Akt信号通路,启动线粒体诱导的凋亡途径.     

Extracellular matrix protects pancreatic beta-cells against apoptosis: role of short- and long-term signaling pathways

We have shown previously that culture of beta-cells on matrix derived from 804G cells and rich in laminin-5 improves their function. The purpose of this study was to investigate whether this matrix protects beta-cells against apoptosis and to elucidate signaling pathways involved. Matrix protected sorted rat beta-cells against apoptosis under standard conditions (11.2 mmol/l glucose, 10% serum), after serum deprivation (1% serum), and in response to interleukin-1beta (IL-1beta; 2 ng/ml), compared with control (poly-L-lysine [pLL]). Caspase-8 activity was reduced in cells cultured on matrix, whereas focal adhesion kinase (FAK), protein kinase B (PKB, or Akt), and extracellular signal-regulated kinase (ERK) phosphorylation was augmented. Treatment (4 h) with an anti-beta1 integrin antibody, with the ERK pathway inhibitor PD98059, and/or with the phosphatidylinositol 3-kinase inhibitor LY294002 augmented cell death on 804G matrix but not on pLL. In long-term assays (48 h), PD98059 but not LY294002 drastically augmented cell death on 804G matrix but did so to a lesser extent on pLL. The protein inhibitor of nuclear factor-kappaB (IkappaBalpha) was overexpressed in cells cultured 18 h on matrix with partial blockade by PD98059. In summary, this study provides evidence for activation of signaling pathways and gene expression by extracellular matrix leading to improved beta-cell survival.     

结缔组织生长因子诱导人近端肾小管上皮细胞整合素连接激酶的表达及与激酶信号途径的关系

目的探讨结缔组织生长因子（CTGF）对人近端肾小管上皮细胞系HK-2整合素连接激酶（ILK）表达的影响，以及丝裂原激活蛋白激酶（MAPK）和磷脂酰肌醇3激酶（P13-K）途径对该因子表达的影响。方法用不同浓度的CTGF作用HK-2细胞24h及50μg／L的CTGF作用HK-2细胞不同时间，以实时PCR和Western印迹方法检测ILKmRNA及蛋白的表达。用信号通路特异性抑制剂预处理，观察其对CTGF的干预作用。结果CTGF呈时间及浓度依赖性诱导人近端肾小管上皮细胞ILK蛋白表达。5、20、50μg／L的CTGF可使ILK表达量分别增加为对照组的3．284、5．103、5．638倍。50μg／LCTGF使ILK的表达在6h开始升高，高峰在48h（为对照组5．740倍），MEK抑制剂PD98059和P13．K抑制剂LY294002显著降低CTGF诱导的HK-2细胞ILK基因和蛋白的表达（P均〈0．05）。p38MAPK抑制剂SB203580对CTGF诱导的ILK表达无显著影响。结论CTGF能诱导HK-2细胞ILK蛋白的表达，该作用可能与ERK1／2和P13-K信号途径激活有关。     

1,25(OH)2D3 ameliorates high glucose-induced podocyte injury via PI3K/p-Akt signalling pathway

Objective To investigate the effect of 1,25(OH)2D3 on high glucose induced podocyte injury and its signal transduction mechanism. Methods Differentiated mouse podocytes were exposed to normal glucose, high glucose, and different concentrations of 1,25(OH)2D3 or LY294002 (a selective PI3K inhibitor) for 24 h. PCR and immunofluorescent staining were used to detect nephrin, podocin, and desmin. Western blotting was used to detect protein expression of nephrin, podocin, desmin, PI3K, Akt and p-Akt. Results Compared with high glucose group, 1,25(OH)2D3 (100 nmol/L and 1000 nmol/L) significantly up-regulated the expression of podocin and nephrin in podocytes induced by high glucose (P＜0.05). Meanwhile, 1,25(OH)2D3 (100 nmol/L) significantly reduced the expression of desmin (P＜0.05). PI3K and p-Akt were obviously reduced in high glucose group. In the presence of 1,25(OH)2D3, the trends were reversed. However the above effects of 1,25(OH)2D3 were abolished when p-Akt was blocked by the PI3K inhibitor LY294002. Conclusions 1,25 (OH)2D3 can inhibit high glucose-induced podocyte injury through PI3K/p-Akt signaling pathway.     

Pancreatic cancer cell proliferation is phosphatidylinositol 3-kinase dependent

BACKGROUND: Genetic mutations found in pancreatic cancer (K-ras, p16, p53) lead to inappropriate cellular proliferation. Mitogens stimulate proliferation via the phosphatidylinositol 3-kinase (PI3K)- and/or the p44/42-mitogen-activated protein kinase [p44/42-MAPK or extracellular signal-regulated kinase (ERK)] signaling pathways. We examined whether inhibition of either PI3K or ERK could limit proliferation in human pancreatic cancer. METHODS: Proliferation was stimulated in quiescent human pancreatic cancer cell lines (BxPC3 and Panc-1) by 10% fetal calf serum (FCS). In certain samples, PD98059 (an ERK inhibitor) or LY294002 (a PI3K inhibitor) was also added. AKT phosphorylation (indicating PI3K activity) and ERK phosphorylation (ERK activation) were determined by Western blot. Cell viability was determined by MTT assay. Cell cycle progression and apoptosis were determined by flow cytometry. A two-tailed t test was used for statistical analysis of the data (significance P < 0.05). RESULTS: LY294002 inhibited the PI3K pathway without affecting ERK activation in response to serum. PD98059 inhibited the ERK pathway specifically. In both BxPC-3 and Panc-1 cell lines, LY294002 inhibited serum-induced proliferation. This was associated with G(1) cell cycle arrest and with an increase in the rate of apoptosis. PD98059 inhibited proliferation only in BxPC3 cells, and to a lesser degree than did LY294002. CONCLUSIONS: PI3K signaling appears to be necessary for G(1)-to-S phase progression and proliferation in pancreatic cancer cells. ERK plays a lesser role in mitogen-induced proliferation. Pharmacological inhibition of PI3K may decrease proliferation, increase apoptosis, and potentially confer therapeutic benefit in pancreatic cancer.     

High uric acid induces phenotypic transition of renal tubular cells via PI3K/Akt signaling pathway

Objective To investigate the effect and the mechanism of epithelial-mesenchymal transition (EMT) in renal tubular cells induced by uric acid. Methods Normal rat kidney tubular cell line (NRK-52E) were exposed to different concentrations of uric acid (100, 200, 400, 600, 800 μmol/L UA) for 48 hours to induce EMT. Morphological changes of the NRK-52E cells were examined under an inverted phase contrast microscope. The protein expression of E-cadherin, α-SMA, p-Akt and Akt were detected by Western blotting. The distribution of E-cadherin and α-SMA were detected by immunofluorescence. NRK-52E cells were pretreated by different concentrations of LY294002(0, 2.5, 5, 10, 15 μmol/L), the inhibitor of PI3K/p-Akt signaling pathway, and then processed by uric acid (400 μmol/L) for 48 hours. Western blotting was used to detect the protein expression of p-Akt and Akt. NRK-52E cells were then divided into four groups: normal group (N), uric acid group (UA), LY294002 group (LY), uric acid with LY294002 group (UA+LY). The protein expression of E-cadherin and α-SMA were detected by Western blotting, the distribution of E-cadherin, α-SMA and p-Akt were detected by immunofluorescence. Results There was abundant cellular expression of E-cadherin in unstimulated renal tubular cells whereas its expression was significantly decreased in uric acid-stimulated cells (P＜0.05). In addition, uric acid induced de novo expression of α-SMA in contrast to almost negative staining in untreated cells (P＜0.05). p-Akt were obviously increased in high uric acid group (P＜0.05) and Akt changed not significantly (P＞0.05). NRK-52E cells transformed into elongated fibroblast-like cells from cuboidal clustered epithelial cells. These indicated that uric acid has induced EMT and activated PI3K/p-Akt signaling pathway in NRK-52E cells. However, the above effects of uric acid were abolished when p-Akt was blocked by the PI3K inhibitor (10, 15 μmol/L LY294002), indicated that LY294002 has reversed the trend of EMT. Conclusions High uric acid induces phenotypic transition of renal tubular cells probably via activating PI3K/Akt signaling pathway.     

PI3K/AKT信号通路及AKR1C3在人瘢痕疙瘩形成中的作用机制研究

目的探讨磷脂酰肌醇-3-激酶(PI3K)/蛋白激酶B(AKT)信号通路、活性氧簇(ROS)、醛酮还原酶家族1成员C3(AKR1C3)在瘢痕疙瘩形成中的可能作用及机制。方法从昆明医科大学第一附属医院皮肤科收集9例瘢痕疙瘩组织标本(男6例,女3例,年龄24~40岁),以及6例进行其他手术的志愿者正常皮肤组织标本(男4例,女2例,年龄20~45岁),部分行组织包埋,部分行成纤维细胞原代培养。(1)免疫组织化学检测瘢痕疙瘩和正常皮肤组织中AKT(丝氨酸磷酸化位点473)[p-AKT(S473)]、AKT(苏氨酸磷酸化位点308)[p-AKT(T308)]和AKR1C3的蛋白相对表达量。(2)CCK-8法检测不同浓度(0、5、10、15、20、25、30、35、40、45、50 mmol/L)PI3K特异性抑制剂2-吗啉代-8-苯基色酮(LY294002)对瘢痕疙瘩成纤维细胞增殖的抑制作用,并筛选出LY294002最佳的实验浓度。(3)以ROS检测试剂盒分别检测不同浓度(0、4、6、8、10、12 mmol/L)ROS抑制剂N-乙酰半胱氨酸(NAC)和15 mmol/L LY294002对瘢痕疙瘩成纤维细胞内ROS水平的影响。(4)将瘢痕疙瘩或正常皮肤成纤维细胞分为对照组(正常培养不进行任何处理)、二甲基亚砜(DMSO)组(0.002%DMSO处理)、LY294002组(15 mmol/L LY294002处理)和NAC组(6 mmol/L NAC处理),定量PCR(qPCR)和蛋白质印迹法分别检测成纤维细胞中AKT mRNA、AKR1C3 mRNA及p-AKT(S473)、p-AKT(T308)和AKR1C3蛋白的表达水平。采用SPSS 20.0软件进行统计学分析,数据以±s表示,两组间比较采用独立样本t检验,多组间比较采用单因素方差分析,两两多重比较采用SNK-q检验,P<0.05表示差异有统计学意义。结果(1)免疫组织化学检测结果显示,瘢痕疙瘩组织中p-AKT(S473)、p-AKT(T308)和AKR1C3的蛋白表达水平分别为16.75±3.30、16.20±1.56、26.69±2.50,均显著高于正常皮肤组织的4.02±1.50、1.82±0.50、1.47±1.07(P<0.01)。(2)瘢痕疙瘩成纤维细胞经不同浓度LY294002干预24 h后,15~50 mmol/L LY294002组成纤维细胞增殖抑制率显著高于对照组(0 mmol/L组)(P<0.01)。LY294002最佳实验浓度为15 mmol/L。(3)不同浓度NAC作用于瘢痕疙瘩成纤维细胞1 h后,各组间ROS水平差异有统计学意义(P<0.01),且6 mmol/L NAC组ROS水平(0.72±0.03)最低。15 mmol/L LY294002组ROS水平显著低于对照组(0 mmol/L组)(0.80±0.01 vs.0.86±0.01,P<0.01)。(4)qPCR检测结果表明,瘢痕疙瘩成纤维细胞对照组中AKT、AKR1C3 mRNA表达量分别为1.38±0.09、1.40±0.05,明显高于正常皮肤成纤维细胞的0.97±0.10、0.98±0.03(P<0.01);经15 mmol/L LY294002处理后,瘢痕疙瘩成纤维细胞AKT mRNA表达量明显低于正常皮肤(0.73±0.05 vs.0.89±0.06,P<0.01);经6 mmol/L NAC处理后,瘢痕疙瘩成纤维细胞AKR1C3 mRNA低于正常皮肤(0.43±0.05 vs.0.86±0.03,P<0.01)。蛋白质印迹法检测结果显示,瘢痕疙瘩成纤维细胞中p-AKT(S473)、p-AKT(T308)、AKR1C3蛋白表达量分别为1.19±0.21、0.92±0.04、0.73±0.08,明显高于正常皮肤的0.24±0.06、0.33±0.05、0.31±0.05(P<0.01);经15 mmol/L LY294002和6 mmol/L NAC处理后,瘢痕疙瘩成纤维细胞中p-AKT(S473)蛋白表达量分别为0.92±0.04、0.80±0.20,p-AKT(T308)蛋白表达量分别为0.42±0.04、0.81±0.05,均明显高于正常皮肤(0.23±0.03、0.22±0.05,0.30±0.06、0.32±0.05),但瘢痕疙瘩成纤维细胞AKR1C3蛋白表达量(0.23±0.05)在15 mmol/L LY294002处理后低于正常皮肤(0.30±0.07),在6 mmol/L NAC处理后(0.33±0.07)高于正常皮肤(0.28±0.06)(P>0.05)。结论活化的PI3K/AKT信号通路和AKR1C3促进了瘢痕疙瘩成纤维细胞增殖及瘢痕疙瘩形成。同时,瘢痕疙瘩成纤维细胞内AKR1C3的升高可加速ROS升高。     

Effects of hyperparathyroidism patients’ serum and klotho protein on the apoptosis of human umbilical vein endothelial cells

Objective To investigate the effects and underlying mechanism of secondary hyperparathyroidism (SHPT) patients’serum and klotho protein on the apoptosis of human umbilical vein endothelial cells (HUVECs). Methods Three types of mixed serum from 15 patients with SHPT (serum S), 10 CKD stage 5 patients without SHPT (serum C) and 15 healthy volunteers (serum H) were collected. HUVECs were incubated with 10% serum H,10% serum C, 10% serum S and 10% serum S plus klotho respectively. The apoptosis rate of endothelial cells was evaluated by flow cytometry. The activity of Caspase-3 was measured by spectrophotometry. The levels of AKT and phosphorylated forms of AKT (p- AKT) were detected by Western blotting (with or without PI3K/AKT inhibitor LY294002). Results The apoptosis of HUVECs was both induced by the serum S and serum C. The apoptosis rate was greater in serum S group than that in serum C group (P＜0.05). The apoptosis was partly inhibited when klotho protein (50-100 μg/L) was added (P＜0.05), accompanying the up-regulation of p-AKT. The above effects could be blocked by LY294002. The activity of Caspase-3 was up-regulated in SHPT group compared to healthy control group (P＜0.05) and the up-regulation could also be inhibited by klotho protein (P＜0.05). Conclusions The apoptosis of HUVECs is induced by the serum from CKD stage 5 patients without SHPT and SHPT patients. Klotho protein can protect the HUVECs from apoptosis by up-regulating p-AKT and inhibiting Caspase-3.     

Sphingosine-1-phosphate-induced smooth muscle cell migration involves the mammalian target of rapamycin

BACKGROUND: Vascular smooth muscle cell (SMC) migration is an important component of the development of intimal hyperplasia. Sphingosine-1-phosphate (S-1-P) is a lipid released from activated platelets with numerous cellular effects including the stimulation of SMC migration in vitro. We examined the role of the mammalian target of rapamycin and ribosomal p70S6 kinase (p70S6K) in S-1-P-induced SMC migration . METHODS: Rat arterial SMCs were cultured in vitro. Linear wound and Boyden microchemotaxis assays of migration were performed in the presence of S-1-P (0.01 to 100 micromol/L) with and without rapamycin (10 nmol/L). Western blotting was performed for phosphorylated and total p70S6K, ERK1/2, and p38(MAPK) after stimulation with S-1-P (0.1 micromol/L), with and without rapamycin pretreatment. Phosphorylation of p70S6K was also assayed after S-1-P treatment in the presence and absence of inhibitors of PI3 kinase (wortmannin, WN, and LY294002, LY), Akt (AktI), p38(MAPK) (SB203580), and MEK1 (PD98059). RESULTS: S-1-P stimulated migration of SMCs in both linear wound and Boyden chamber assays compared to control (P < .05); these responses were inhibited by rapamycin to below the level of control (P < .05 vs S-1-P alone for both assays) in a dose-dependent manner (inhibitory concentration of 50%, 10 nmol/L). S-1-P stimulated phosphorylation of ERK1/2, p38(MAPK), and p70S6K, which peaked at 5 minutes for ERK1/2 and p38(MAPK) and10 minutes for p70S6K (2-fold increase over control for each, P < .05). Rapamycin prevented the phosphorylation of p70S6K at the Thr 389 site (which correlates with enzyme activity), reduced ERK1/2 phosphorylation, but had no effect on the Thr 421/Ser 424 site or on p38(MAPK) phosphorylation. Wortmannin and LY294002 inhibited phosphorylation of the Thr 389 site of p70S6K. AktI and SB203580 had no effect on p70S6K, whereas PD98059 had a marginal effect. CONCLUSIONS: S-1-P-induced SMC migration was completely inhibited by rapamycin, indicating that the p70S6K pathway is involved. This mechanism likely involves modulation of the ERK1/2 pathway. S-1-P stimulates phosphorylation of p70S6K in a MEK1-dependent, PI3 kinase-dependent, but Akt-independent manner.