黄芪多糖通过PI3K/AKT/mTOR促进激素性骨质疏松症大鼠成骨细胞增殖

目的 探讨黄芪多糖在体内外通过PI3K/AKT/mTOR信号通路对糖皮质激素诱导的骨质疏松症（glucocorticoid-induced osteoporosis,GIOP）的保护作用。方法 从分化的骨髓间充质干细胞（bone marrow mesenchymal stem cells,BM-MSCs）中培养成骨细胞,分为PBS组、模型组、LY294002组、黄芪多糖组和LY294002+黄芪多糖干预组。通过CCK-8法和碱性磷酸酶（alkaline phosphatase,ALP）染色检测细胞增殖和分化。MDC染色观察自噬体的形成。Western blot检测Beclin-1、p62等信号通路及自噬相关因子的蛋白表达。大鼠分为对照组、模型组、LY294002组、黄芪多糖组和LY294002+黄芪多糖组。比较各组大鼠的骨密度、骨组织形态学参数、组织中通路和自噬相关因子的表达。结果 黄芪多糖促进成骨细胞的增殖和分化能力（P＜0.05）。与模型组相比,黄芪多糖组PI3K/AKT/mTOR通路相关磷酸化蛋白的表达、成骨细胞的增殖分化能力、自噬体及自噬相关因子的表达均升高,但在LY294002组中发现了相反的结果（P＜0.05）。在体内实验中,与模型组相比,GIOP大鼠通过黄芪多糖干预改善了骨密度和骨形态参数,并提高了软骨组织中自噬相关因子的表达,而LY294002干预则表现出相反的结果（P＜0.05）。LY294002部分逆转了黄芪多糖对GIOP中成骨分化和骨形态参数的影响。结论 黄芪多糖通过PI3K/AKT/mTOR通路对GIOP发挥保护作用,可能与诱导自噬和促进成骨细胞增殖有关。     

PI3K/AKT通路和S1PR2在急性梗阻性胆管炎诱导大鼠全身炎症反应中的作用

目的研究急性梗阻性胆管炎(AOC)大鼠模型中外周血单个核细胞(PBMCs)中磷脂酰肌醇-3-羟激酶(PI3K)/AKT通路和鞘氨醇-1-磷酸受体2(S1PR2)的激活情况以及其对大鼠全身炎症反应的影响。方法①体外实验:分离和培养清洁级大鼠PBMCs,然后将其分为磷酸盐缓冲溶液对照组、单独PI3K抑制剂LY294002处理组、脂多糖处理组和脂多糖+LY294002处理组4组,收集各组细胞的上清液和总蛋白,检测细胞上清液中炎性因子肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)水平以及细胞中PI3K、AKT磷酸化水平和S1PR2蛋白的变化。②体内实验:60只清洁级SD大鼠被随机分为假手术组、单独PI3K抑制剂LY294002处理组、AOC模型组及AOC模型+LY294002处理组4组,记录大鼠存活情况,检测大鼠血清中肝功能丙氨酸转氨酶(ALT)、门冬氨酸氨基转移酶(AST)和总胆红素(TBIL)水平及血清中TNF-α和IL-6的水平以及大鼠PBMCs中PI3K、AKT磷酸化水平和S1PR2蛋白的变化。结果①体外实验结果:脂多糖+LY294002处理组细胞上清液中TNF-α和IL-6水平均明显低于脂多糖处理组(P0.050),PI3K、AKT磷酸化水平和S1PR2的蛋白水平亦明显低于脂多糖处理组(P0.050)。②体内实验结果:AOC模型+LY294002处理组大鼠的生存率高于AOC模型组,血清中肝功能ALT、AST、TBIL和炎性因子TNF-α和IL-6水平均明显低于AOC模型组(P0.050),PI3K和AKT磷酸化水平及S1PR2蛋白表达水平也明显低于AOC模型组(P0.050)。结论抑制AOC模型大鼠中PBMCs中PI3K/AKT通路的活化,可降低S1PR2的表达,且能抑制AOC诱导的大鼠全身炎症反应。     

红景天苷激活PI3K/AKT通路改善绝经后骨质疏松症实验研究

目的探讨红景天苷激活PI3K/AKT通路改善绝经后骨质疏松症的作用。方法建立绝经后骨质疏松症大鼠模型,随机分为模型组、LY294002(PI3K/Akt通路抑制剂)组、红景天苷组、红景天苷+LY294002组,每组12只,另取12只设为假手术组。分组处理后,通过骨科生物力学测试仪测定大鼠股骨生物力学指标弹性模量、最大载荷、屈服载荷;测定大鼠股骨骨矿盐含量;运用苏木精-伊红(HE)染色检测各组大鼠骨组织病理变化;通过酶联免疫吸附法(ELISA)检测血清白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)水平;运用蛋白免疫印迹法检测脑组织PI3K/Akt通路相关蛋白表达情况。结果与假手术组相比,模型组大鼠骨组织呈现骨小梁稀疏断裂、数目明显减少,有较多空隙、不能连接成网等病理损伤,血清IL-6及TNF-α水平均显著升高(P0.05),股骨弹性模量、最大载荷、屈服载荷、骨矿盐含量、骨组织p-PI3K/PI3K、p-Akt/Akt水平均显著降低(P0.05);与模型组相比,红景天苷组大鼠骨组织病理损伤减轻,血清IL-6及TNF-α水平降低(P0.05),股骨弹性模量、最大载荷、屈服载荷、骨矿盐含量、骨组织p-PI3K/PI3K、p-Akt/Akt水平升高(P0.05); LY294002组大鼠骨组织病理损伤加重,血清IL-6及TNF-α水平升高(P0.05),股骨弹性模量、最大载荷、屈服载荷、骨矿盐含量、骨组织p-PI3K/PI3K、p-Akt/Akt水平降低(P0.05)。与LY294002组相比,红景天苷+LY294002组大鼠骨组织病理损伤减轻,血清IL-6及TNF-α水平降低(P0.05),股骨弹性模量、最大载荷、屈服载荷、骨矿盐含量、骨组织p-PI3K/PI3K、p-Akt/Akt水平升高(P0.05)。与红景天苷组相比,红景天苷+LY294002组大鼠骨组织病理损伤加重,血清IL-6及TNF-α水平升高(P0.05),股骨弹性模量、最大载荷、屈服载荷、骨矿盐含量、骨组织p-PI3K/PI3K、p-Akt/Akt水平降低(P0.05)。结论红景天苷可能通过激活PI3K/Akt通路改善绝经后骨质疏松症。     

阻断PI3K/AKT/mTOR通路增强顺铂诱导的人皮肤黑素瘤细胞株A375凋亡的机制研究

目的:本实验探讨抑制PI3K/AKT/mTOR通路对顺铂诱导人皮肤黑素瘤细胞株A375细胞凋亡作用及其机制。方法:用顺铂处理人皮肤黑素瘤细胞株A375细胞后Western blot检测细胞凋亡、PI3K/AKT/mTOR通路的活化情况以及细胞增殖-毒性检测试剂盒(Cell Counting Kit-8,CCK-8)。用PI3K的抑制剂LY294002(LY)和mTOR的抑制剂雷帕霉素(Rapamycin,Rap)分别预处理以研究其对顺铂处理后人皮肤黑素瘤细胞株A375细胞凋亡的协同作用。为进一步探索阻断PI3K/AKT/mTOR通路对顺铂处理后人皮肤黑素瘤细胞株A375细胞凋亡的协同作用机制,采用Western blot检测阻断PI3K/AKT/mTOR后联用顺铂处理人皮肤黑素瘤细胞株A375细胞中Bcl-2、Bcl-xl蛋白表达。结果:顺铂处理后的A375黑素瘤细胞中PARP的活化剪切体表达量水平呈浓度和时间依赖性增加,细胞活力呈浓度和时间依赖性降低(P0.05)。顺铂处理A375黑素瘤细胞后PI3K/AKT/mTOR通路的活化。阻断PI3K/AKT/mTOR通路再用顺铂联合处理A375黑素瘤细胞后PARP的活化剪切体表达量明显上调以及细胞活力明显降低(P0.05)。阻断PI3K/AKT/mTOR通路后再用顺铂联合处理A375黑素瘤细胞发现Bcl-2蛋白和Bcl-xl表达水平下调。结论:阻断PI3K/AKT/mTOR通路对顺铂诱导的细胞凋亡具有协同作用,该协同作用可能与Bcl-2和Bcl-xl蛋白下调有关。     

PI3K/AKT抑制剂对前列腺增生的影响及机制研究

目的:探讨磷脂酰肌醇3激酶/蛋白激酶B(PI3K/PKB或PI3K/AKT)信号通路抑制剂对前列腺增生的影响及机制。方法:选用鼠龄12周的雄性SD大鼠48只,随机分为4组:假手术对照组;BPH模型组;LY294002 50 mg组和LY294002 100 mg组,每组12只。大鼠去势后肌注丙酸睾酮10 mg/(kg.d)连续30 d建模,LY294002 50 mg组和100 mg组同时肌注LY294002 50 mg/kg和100 mg/kg,隔日1次。给药30 d后,切除各组大鼠前列腺组织,称取前列腺重量,切片观察前列腺组织细胞结构变化。免疫组化法检测K i-67、凋亡相关蛋白Bc l-2与Bax的表达情况;核酸末端原位标记法(TUNEL)检测细胞凋亡情况。结果:各组大鼠前列腺湿重(mg)和前列腺指数:假手术对照组:551±10.8,1.61±0.05;模型组:687±13.8,2.15±0.12;LY294002 50 mg组:623±23.5,1.95±0.11,与模型组相比,差异有显著性(P<0.05);LY294002 100 mg组:561±12.6,1.71±0.18,与模型组相比,差异具有极显著性(P<0.01)。凋亡相关蛋白Bax与Bc l-2的表达:假手术对照组:16.7%,16.7%;模型组:16.7%,58.3%;LY294002 50 mg组:33.3%,33.3%,与模型组相比,差异有显著性(P<0.05);LY294002 100 mg组:50.0%,25.0%,与模型组相比,差异极有显著性(P<0.01)。增殖和凋亡指数(%):假手术对照组:上皮组织14.2±6.4,6.5±1.8,间质组织7.6±2.6,2.5±0.3;模型组:上皮组织50.9±12.8,2.7±1.4,间质组织16.5±5.7,1.3±0.8;LY294002 50 mg组:上皮组织32.0±13.8,6.2±2.5,间质组织12.1±3.8,1.6±1.1;与模型组相比,差异有显著性(P<0.05);LY294002 100 mg组:上皮组织17.8±14.7,7.4±3.6,间质组织9.5±3.4,2.2±1.3;与模型组相比,差异有显著性(P<0.05)或极显著性(P<0.01)。结论:前列腺增生动物模型前列腺细胞增殖增加和凋亡的相对减少参与了BPH的发生发展过程。PI3K/AKT介导的信号通路在前列腺增生的发生发展过程中起重要作用,阻断PI3K/AKT信号通路具有抑制前列腺增生的作用。     

PI3K/Akt/mTOR信号通路在依达拉奉减轻老龄大鼠术后认知功能障碍中的作用

目的评价磷脂酰肌醇3-激酶(PI3K)/丝氨酸-苏氨酸蛋白激酶(Akt)/哺乳动物雷帕霉素靶蛋白(mTOR)信号通路在依达拉奉减轻老龄大鼠术后认知功能障碍中的作用。方法健康雄性SD大鼠60只, 20月龄, 体质量600～700 g, 采用随机数字表法分为4组(n=15):对照组(C组)、手术组(O组)、依达拉奉组(E组)和PI3K抑制剂LY294002组(LY组)。O组、E组和LY组于3%七氟烷麻醉下行剖腹探查术。E组和LY组术前30 min时腹腔注射依达拉奉3 mg/kg, 同时LY组尾静脉注射LY294002 0.3 mg/kg。术后3 d时行旷场实验评估大鼠自发活动能力, 然后行Morris水迷宫实验评估大鼠认知功能。行为学实验结束后处死大鼠分离海马组织, 采用Western blot法测定磷酸化PI3K(p-PI3K)、磷酸化Akt(p-Akt)、磷酸化mTOR(p-mTOR)、突触素(SYP)和突触后致密蛋白95(PSD-95)的表达水平, 行高尔基染色记录海马CA1区神经元树突长度, 计算树突棘密度。结果 4组运动速度、路程及旷场中心停留时间比较差异无统计学意义(P>...     

肝癌细胞VEGF转录调控的信号传导通路

目的研究磷脂酰肌醇3-激酶(PI3K)和p42／p44丝裂源激活的蛋白激酶(MAPK)在肝癌细胞血管内皮生长因子(VEGF)转录调控中的作用。方法应用缺氧诱导剂氯化钴或重组人表皮生长因子(EGF)刺激HepG2细胞中VEGF的转录，在此过程中应用PI3K特异性阻断剂LY294002或p42／p44 MAPK特异性阻断剂PD98059干预，采用半定量逆转录PCR检测VEGF mRNA表达的变化。结果氯化钴或EGF可以诱导HepG2细胞中VEGF的表达。PI3K阻断剂LY294002可以在一定范围内浓度依赖性地抑制VEGF mRNA的表达，而p42／p44 MAPK阻断剂PD98059对VEGF mRNA的表达无抑制作用。结论肝癌细胞VEGF的转录调控受PI3K通路调控，而不受p42／p44 MAPK调控。     

高糖通过PI3K-AKT-mTOR信号通路增加足细胞自噬

目的 研究高糖引起足细胞自噬变化及其相关的信号机制.方法 培养的足细胞被分为6组,正常浓度葡萄糖(NG)组、高浓度葡萄糖(HG)组、NG+雷帕霉素(Rap)组、HG+Rap组、NG+LY294002组和HG+LY294002组.观察自噬增强剂Rap和PI3K抑制剂LY294002对高糖条件下培养的足细胞自噬和凋亡的影响.电镜和吖啶橙染色观察细胞内自噬体的形成;Western印迹检测自噬标志蛋白微管相关蛋白1轻链3(LC3)和自噬血管基因Beclin-1的表达;通过阻断自噬的信号通路观察磷脂酰肌醇3激酶-蛋白激酶B-哺乳动物雷帕霉素靶蛋白(PI3K-AKT-mTOR)相关蛋白AKT和mTOR的磷酸化水平的改变.结果 高糖可导致足细胞凋亡增加,促进足细胞内自噬体和自噬相关蛋白表达增加(均P＜ 0.05).与高糖组相比,HG+ Rap组LC3-Ⅱ和Beclin-1的表达增加(均P＜0.05);LY294002部分抑制高糖导致的LC3-Ⅱ和Beclin-1表达增加(均P＜0.05).与高糖组相比,HG+ LY294002组足细胞内AKT磷酸化的水平增加(P＜0.05),mTOR的磷酸化水平降低(P＜0.01);HG+ LY294002组足细胞的AKT和mTOR磷酸化水平较高糖组均降低(均P＜0.05).结论 高糖可促进足细胞的自噬和凋亡,推测高糖诱导的足细胞自噬作用部分通过PI3K-AKT-mTOR信号通路调节实现的.     

基于PI3K/Akt通路研究利拉鲁肽对2型糖尿病骨质疏松大鼠的作用

目的基于磷脂酰肌醇-3-激酶/丝苏氨酸蛋白激酶(phosphateidylinositol-3 kinase/serine-threonine kinase,PI3K/Akt)通路研究利拉鲁肽对2型糖尿病性骨质疏松(type 2 diabetic osteoporosis,T2DOP)大鼠的影响。方法高脂高糖、腹腔注射30mg/kg链脲佐菌素(STZ)并摘除卵巢建立T2DOP大鼠模型,将大鼠随机分为模型组、利拉鲁肽组、利拉鲁肽+LY294002组;正常饲养大鼠作为正常组,每组10只。大鼠体重,空腹血糖,股骨组织形态,血清中骨保护素(OPG)、细胞核因子KB受体活化因子配基(RANKL)水平,骨密度,股骨组织中磷酸化-PI3K(p-PI3K)、PI3K、磷酸化-Akt(p-Akt)、Akt蛋白水平进行比较。结果模型组大鼠体重、FBG,血清中RANKL水平升高(P0.05),血清中OPG水平、股骨组织骨密度,p-PI3K/PI3K、p-Akt/Akt蛋白水平降低(P0.05);而利拉鲁肽组大鼠体重、FBG,血清中RANKL水平降低(P0.05),血清中OPG水平、股骨组织骨密度,pPI3K/PI3K、p-Akt/Akt蛋白水平升高(P0.05);利拉鲁肽添加PI3K抑制剂LY294002后逆转利拉鲁肽症状。结论利拉鲁肽激活PI3K/Akt通路实现对T2DOP大鼠骨质疏松的保护。     

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...     

抗疏健骨颗粒对去卵巢骨质疏松大鼠血清骨代谢及骨组织自噬水平的影响

目的研究抗疏健骨颗粒对去卵巢骨质疏松(osteoporosis,OP)大鼠骨稳态及自噬相关因子的影响,探讨抗疏健骨颗粒干预OP的作用机制。方法将60只SD大鼠随机分为5组:假手术组、模型组、抗疏健骨颗粒低、中、高剂量组。除假手术组外,其余4组建立去卵巢大鼠OP模型。正常喂养12周检测模型建成后,给予抗疏健骨颗粒干预12周,采用ELLSA法测定血清ALP、BGP和TRACP水平和股骨GPR48、ATF4含量;蛋白印迹法(Western blotting)检测股骨中AMPK、LC3、Beclin1和P62蛋白表达。结果抗疏健骨颗粒可显著降低OP大鼠血清ALP、BGP和TRACP水平,升高股骨GPR48、ATF4含量,上调AMPK磷酸化水平及LC3、Beclin1蛋白表达,降低P62水平,差异有统计学意义(P0.05)。抗疏健骨颗粒各剂量组中,中剂量组效果显著,与其他两组相比,差异有统计学意义(P0.05)。结论抗疏健骨颗粒可调节血清、骨组织中骨代谢指标,减轻去卵巢大鼠OP的发生,其机制可能与通过骨组织中AMPK调节自噬通路有关,通过恢复自噬水平,促进骨生成,进而维持骨平衡。     

PI3K/AKT pathway promotes keloid fibroblasts proliferation by enhancing glycolysis under hypoxia

Our previous study demonstrated altered glucose metabolism and enhanced phosphorylation of the PI3K/AKT pathway in keloid fibroblasts (KFb) under hypoxic conditions. However, whether the PI3K/AKT pathway influences KFb cell function by regulating glucose metabolism under hypoxic conditions remains unclear. Here, we show that when PI3K/AKT pathway was inactivated with LY294002, the protein expression of glycolytic enzymes decreased, while the amount of mitochondria and mitochondrial membrane potential increased. The key parameters of extracellular acidification rate markedly diminished, and those of oxygen consumption rate significantly increased after inhibition of the PI3K/AKT pathway. When the PI3K/AKT pathway was suppressed, the levels of reactive oxygen species (ROS) and mitochondrial ROS (mitoROS) were significantly increased. Meanwhile, cell proliferation, migration and invasion were inhibited, and apoptosis was increased when the PI3K/AKT pathway was blocked. Additionally, cell proliferation was compromised when KFb were treated with both SC79 (an activator of the PI3K/AKT pathway) and 2-deoxy-d-glucose (an inhibitor of glycolysis), compared with the SC79 group. Moreover, a positive feedback mechanism was demonstrated between the PI3K/AKT pathway and hypoxia-inducible factor-1α (HIF-1α). Our data collectively demonstrated that the PI3K/AKT pathway promotes proliferation and inhibits apoptosis in KFb under hypoxia by regulating glycolysis, indicating that the PI3K/AKT signalling pathway could be a therapeutic target for keloids.     

Inhibition of the PI3K/AKT Pathway Reduces Tumor Necrosis Factor‐Alpha Production in the Cellular Response to Wear Particles In Vitro

Joint replacement is the most effective treatment for end‐stage osteoarticular disease. However, macrophage‐mediated aseptic loosening of joint prosthesis severely hampers the clinical effects of joint replacement. Until now, the mechanism by which macrophages regulate the secretion of inflammatory cytokines after particle stimulation is not clear. It is well known that the PI3K/AKT pathway participates in multiple cellular processes, including cell growth, survival, and inflammation. However, whether the PI3K/AKT pathway participates in the proinflammatory response of macrophages after particle stimulation and secondary aseptic loosening is still unknown. In this study, ceramic and titanium particles of different sizes were prepared to stimulate macrophages. LY294002, a specific inhibitor of PI3K, was pretreated prior to particle stimulation. The expression of tumor necrosis factor‐alpha (TNF‐α) and all the subunits of PI3K and AKT were detected by real‐time polymerase chain reaction, enzyme‐linked immunosorbent assay, and Western blot. The result showed that LY294002 could suppress the RNA and protein expression of TNF‐α in RAW264.7 cells after stimulation of different particles. The subunits of PI3K (p110β and p85β), followed by activation of phosphor‐AKT (Ser473), participated in the regulation of activating macrophages by wear particles, ultimately resulting in the secretion of TNF‐α.     

Attenuation of high glucose induced podocyte injury by ursolic acid up-regulating autophagy level

Objective To investigate the effects of ursolic acid (UA) on autophagy and podocyte injury induced by high glucose. Methods Conditionally immortalized murine podocyte were cultured in high glucose, the effect of PI3K inhibitor LY294002 and ursolic acid treatment were observed. The miR-21 expression was detected using RT-qPCR. The activation of PTEN-PI3K/Akt/mTOR pathway, expression of autophagy-related protein and podocyte marker protein were determined by Western blot. Immunofluorescence staining showed the expression of podocyte marker protein and endogenous accumulation of LC3. Autophagosomes were observed using electron microscopy. Results Compared with normal control group,the cells exposed to high glucose condition showed down-regulated synaptopodin, podocin and nephrin expression (P＜0.01), up-regulated miR-21 expression (P＜0.01), down-regulated PTEN expression (P＜0.01), up-regulated p85-P13K, phospho(p)-Akt, p-mTOR,p62/SQSTMI, expression and down-regulated LC3II and Beclin1 expression (all P＜0.01). Ursolic acid and LY294002 promoted synaptopodin, podocin and nephrin expression (all P＜0.01), up-regulated LC3II, Beclin1 expression and down-regulated p62/SQSTM1 expression (all P＜0.01), down-regulated p85-PI3K, p-Akt, p-mTOR expression (all P＜0.01). However, LY294002 did not affect the expression of miR-21 and PTEN. Ursolic acid inhibited miR-21 expression and upregulated PTEN level. Conclusions The podocyte injury is associated with defective autophagy level under high glucose condition. Ursolic acid could reduce podocyte injury by increasing autophagy level via inhibition of miR-21 expression and PTEN/Akt/mTOR pathway.     

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。