生长抑素受体-2基因逆转上皮-间充质转化抑制肝癌细胞侵袭转移机制的研究

目的 观察生长抑素受体-2(SSTR2)基因对肝癌细胞株MHCC-97H侵袭转移及上皮-间充质转化(EMT)特性的影响.方法 构建慢病毒3FLAG-puromycin-LV及SSTR2-LV,转染肝癌细胞株MHCC-97H,噻唑蓝(MTT)、免疫荧光检测转染效率.采用Transwell侵袭实验和迁移实验分别检测未转染细胞(空白对照组)、转染3FLAG-puromycin-LV细胞(阴性对照组)和转染SSTR2-LV细胞(实验组)侵袭转移能力的强弱.镜下观察转染前后细胞形态的变化,免疫荧光检测转染前后细胞上皮表型蛋白和间质表型蛋白的定位和表达,实时定量聚合酶链反应(Real-time PCR)检测转染后细胞SSTR2的表达,Westem blot检测E-钙黏蛋白(E-cadherin)、N-钙黏蛋白(N-cadherin)、波形蛋白(Vimentin)蛋白的表达.结果 SSTR2-LV可以有效转染肝癌细胞株MHCC-97H,稳定表达SSTtR2的mRNA和蛋白.转染SSTR2-LV的肝癌细胞株MHCC-97H较空白对照组和阴性对照组侵袭迁移能力明显受到抑制(P＜0.05).镜下观察肝癌细胞株MHCC-97H转染SSTR2-LV后,由成纤维细胞样、排列分散,转变为细胞排列紧密如铺路石.免疫荧光染色结果可见肝癌细胞株MHCC-97H转染后细胞膜表达的E-cadherin荧光由胞质转移至细胞周边浓聚,而Vimentin的荧光强度较前下降.采用Western blot进行蛋白定量分析,转染后MHCC-97H细胞上皮表型标志性蛋白E-cadherin、β-连环蛋白(β-catenin)表达量增高,间质表型标志性蛋白N-cadherin、Vimentin表达量减少,差异具有统计学意义(P＜0.05).结论 转染再表达SSTR2MHCC-97H细胞可以增加上皮表型蛋白表达,减少间质表型蛋白,从而逆转肝癌细胞EMT,导致肿瘤细胞侵袭能力减弱.     

草酸钙结晶肾损伤模型小鼠肾小管上皮细胞转分化的实验研究

目的:研究乙醛酸盐诱导所致草酸钙结晶肾损伤模型小鼠中肾小管上皮细胞转分化的发生情况。方法:选择C57BL/6J小鼠连续腹腔注射乙醛酸盐建立草酸钙结晶肾损伤模型,应用HE染色及冯库萨染色分别观察肾组织结构变化及钙盐沉积情况,并应用免疫荧光双染、Western-blot观察肾小管上皮细胞间充质转分化(epithelial mesenchymal transtion,EMT)的情况。结果:随着连续腹腔注射乙醛酸盐时间的延长,小鼠肾组织HE染色结果显示,近端肾小管管腔逐渐扩张,且肾小管上皮细胞逐渐出现肿胀及变形,基底膜逐渐裸露;冯库萨染色结果显示近端小管腔内黑色钙盐沉积逐渐增加;免疫荧光双染、Western blot结果均显示肾小管上皮标志E-cadherin及Pan-ck逐渐丢失,而间质标志α-SMA及Vimentin的表达则逐渐增加,Western blot检测结果显示随着乙醛酸盐干预的增强,Rho相关卷曲螺旋形成蛋白激酶(rho associated coiled coil forming protein kinase,ROCKI)表达也逐渐增加,且在干预第3天即达高峰。结论:乙醛酸盐诱导所致草酸钙结晶肾损伤模型早期即出现EMT,启动了肾间质纤维化的进程。     

氯沙坦对肾间质纤维化的抑制作用

目的:肾小管间质纤维化(tubulointerstitial fibrosis,TIF)是慢性肾脏病进展为终末期肾病(end-stage renaldisease,ESRD)的重要共同通路。血管紧张素ⅡAT1受体阻断剂--氯沙坦对慢性肾脏病具有保护作用,但其能否抑制肾小管间质纤维化及其可能的机制尚不清楚。本实验通过在体内构建单侧输尿管梗阻(unilateral ureteral obstruction,UUO)大鼠模型,观察氯沙坦对肾小管间质纤维化的抑制作用及其可能机制。方法:50只SD大鼠分为3组:假手术组(n=10),UUO组(n=20),UUO氯沙坦治疗组(n=20)。术后氯沙坦治疗组予以氯沙坦灌胃,剂量20mg·kg-1·d-1。分别在术后第7天、第14天处死大鼠。冰冻组织行E-cadherin,Vimentin,α-SMA,β-catenin和ZEB1免疫荧光染色及Western blot分析。结果:UUO组大鼠第7天组织病理学改变为肾小管管腔扩大,小管萎缩,间质增宽及炎细胞浸润,部分小管间质纤维化;第14天间质纤维化表现更为严重。与对照组相比,UUO模型组大鼠第7天、第14天肾间质上皮标志物E-cadherin表达显著下降,而Vimentin,α-SMA,β-catenin和ZEB1表达增加。与UUO模型组比较,UUO氯沙坦治疗组大鼠肾小管间质纤维化改变明显减轻,肾组织E-cadherin表达增加,Vimentin,α-SMA,β-catenin和ZEB1的表达减少。结论:氯沙坦可抑制大鼠体内的肾小管间质纤维化,其机制可能与氯沙坦抑制小管上皮间充质转化相关因子β-catenin/ZEB1的表达有关。     

婴幼儿血管瘤间充质干细胞的分离鉴定及其在血管瘤组织中的定位观察

目的 探索周细胞是否是血管瘤间充质干细胞的来源,及间充质干细胞与婴幼儿血管瘤消退过程中的脂肪组织增生的关系.方法 采用贴壁筛选法从增生期血管瘤中分离间充质干细胞,应用流式细胞仪和免疫荧光染色检测细胞抗原表型.免疫组化染色观察CD133和PPAR-γ在增生期血管瘤组织中的表达,并以CD31和α-SMA行共染色.结果 血管瘤间充质干细胞为成纤维细胞样,表达CD133、PPAR-γ、CD105、CD90、CD29和Vimentin,不表达CD45、CD34、CD31和flt-1.部分细胞表达α-SMA.大部分细胞表达PDGFR-β.NG2、Desmin和RGS-5无表达.免疫组化染色证实CD133、PPAR-γ和α-SMA共表达于血管瘤组织的微血管周围.结论 细胞形态和抗原表型初步证实,本研究分离的细胞为间充质干细胞,免疫组化染色证实间充质干细胞存在于血管瘤组织的微血管周围.研究结果提示,周细胞是血管瘤间充质干细胞的来源.     

氯沙坦含药血清对肾小管上皮-间充质转分化的抑制作用

目的:肾小管上皮细胞-间充质转分化(epithelial-to-mesenchymal transition,EMT)是肾小管间质纤维化(tubulointerstitial fibrosis,TIF)的关键发病机制,而肾小管间质纤维化是慢性肾脏病进展为终末期肾病(end-stage renal dis-ease,ESRD)的重要共同通路。血管紧张素ⅡAT1受体阻断剂氯沙坦对于延缓慢性肾脏病进展有一定的作用,但其能否抑制肾小管上皮细胞-间充质转分化继而抑制肾间质纤维化尚不清楚。本实验通过体外TGF-β1诱导HK-2细胞向间充质细胞转分化,观察氯沙坦对肾小管上皮细胞-间充质转分化的抑制作用及其可能机制。方法:在体外使用TGF-β1诱导HK-2细胞表型改变并给予氯沙坦大鼠含药血清干预。氯沙坦大鼠含药血清按照既定的操作程序获取。HK-2细胞行E-cadher-in,Vimentin,β-catenin和ZEB1免疫荧光染色及Western blot分析。结果:TGF-β1诱导肾小管上皮细胞HK-2转化为间充质细胞,细胞形态由卵圆形变为长梭形,上皮标志物E-cadherin表达下调,间充质标志物Vimentin表达上调,上皮细胞-间充质转分化相关分子β-catenin在胞浆、胞核的积聚增多以及ZEB1表达增强;氯沙坦大鼠含药血清能够部分抑制TGF-β1诱导的HK-2转化为间充质表型,并维持HK-2细胞的上皮表型,抑制E-cadherin的表达下调和Vimentin的表达上调;同时抑制β-catenin在胞浆、胞核的积聚以及ZEB1的表达。结论:研究结果提示氯沙坦可抑制体外的肾小管上皮细胞-间充质转分化,其机制可能与氯沙坦抑制β-catenin/ZEB1通路有关。     

人类肾小球肾炎中肾小管及间质细胞表型转化的研究

目的观察人类肾小球肾炎时肾小管-间质细胞发生的表型转化现象.方法对34例肾小球肾炎患者肾穿刺标本进行免疫组织化学染色,观察α-平滑肌肌动蛋白(α-SMA)、波形蛋白(vimentin,Vim)、角蛋白(cytokeratin,CK)、增殖细胞核抗原(PCNA)及Ⅳ型胶原(ColⅣ)表达,并进行透射电镜观察.结果在人类肾小球肾炎中,肾小管上皮细胞可出现间质细胞标志物波形蛋白及α-SMA表达,并可游离至肾间质中;肾间质中α-SMA阳性的肌纤维母细胞(myofibroblast,Myo-FB)增多,与波形蛋白阳性的间质细胞分布区域近似,并伴有Ⅳ型胶原的聚积增多.α-SMA阳性的肾小管-间质细胞均有增殖现象.结论人类肾小球肾炎时,肾小管上皮细胞和间质成纤维细胞可发生向肾间质肌纤维母细胞的表型转化,参与肾间质纤维化的发展.     

转染丙型肝炎病毒核心基因对胆管癌细胞上皮-间叶样表型转化的影响

目的 观察丙型肝炎病毒核心蛋白(HCVc)在诱导胆管癌细胞上皮-间叶样表型转化中的作用.方法 将转染的胆管癌细胞(QBC939)分成空载体对照组和HCVc基因实验组,通过半定量逆转录-聚合酶链反应(RT-PCR)和免疫细胞化学的方法 分别检测两组细胞中HCVc、上皮性标志物上皮性钙黏附素(E-cadherin)、间叶性标志物波形蛋白(Vimentin)、纤维连接蛋白(Fibronectin)的mRNA及蛋白的表达.结果 转染HCVc基因的实验组细胞能够较好地表达该基因,而空载体对照组未见其表达,实验组细胞E-cadherin的mRNA表达水平(0.44±0.03)较对照组(0.56±0.03)明显下降(P＜0.05),而其Vimentin(0.61±0.01)、Fibronectin(0.58±0.05)表达水平较对照组(0.38±0.02)、(0.42±0.03)明显增加(P＜0.05).两组细胞各标志物蛋白表达差异明显,转染HCVc基因的实验组细胞较空载体对照组细胞E-cadherin表达明显缺失,Vimentin、Fibronectin明显增高.结论 丙型肝炎病毒核心蛋白可能诱导胆管癌细胞发生了上皮-间叶样表型转化.     

MARCH5通过诱导上皮间质转化促进肝癌细胞转移

目的 探讨线粒体E3泛素蛋白连接酶MARCH5[membrane-associated ring finger（C3HC4）5]在肝癌转移中的调控作用。方法 （1）采用生物信息学方法分析TCGA库中肝癌细胞中MARCH5表达是否发生了异常改变,并进一步分析MARCH5表达与肝癌患者预后相关性。（2）采用细胞生物学方法下调人肝癌细胞HLE中MARCH5表达后,利用划痕实验与Transwell侵袭实验分析对细胞迁移与侵袭能力的影响;下调人肝癌细胞HLE中MARCH5表达后,利用qRT-PCR实验分析对上皮间质转化标志分子（上皮标志E-cadherin与ZO-1;间质标志N-cadherin与Vimentin）表达的影响。结果 （1）与正常肝组织相比,肝癌组织中MARCH5表达显著上调（P＜0.001）,尤其在转移性肝癌组织中（P＜0.001）;MARCH5高表达与患者不良预后显著相关（P=0.027）。（2）下调MARCH5表达可显著抑制人肝癌细胞HLE的迁移与侵袭能力;下调MARCH5表达后HLE细胞中上皮细胞标志分子E-cadherin与ZO-1表达显著上调,而间质细胞标志分子N-cadherin与Vimentin表达显著下调（P＜0.05）。结论 MARCH5表达上调可能通过诱导上皮间质转化促进肝癌细胞的迁移与侵袭。     

大鼠胰腺星状细胞分离培养与鉴定

目的：分离培养大鼠胰腺星状细胞,为体外研究胰腺纤维化提供细胞模型。方法：采用酶消化结合Nycodenz密度梯度离心法分离胰腺星状细胞,通过倒置显微镜观察细胞形态,油红O染色和免疫细胞化学染色desmin,α-SMA进行细胞鉴定,并绘制传代后细胞生长曲线。结果：原代培养的大鼠胰腺星状细胞呈星形或梭形生长;原代胰腺星状细胞油红O染色胞浆均可见红色密集脂滴,直至传代后消失;原代胰腺星状细胞培养48 h后,desmin表达开始减弱,α-SMA表达开始增强;传代后desmin基本不表达,α-SMA阳性表达100%;传代后第3 d-5 d的胰腺星状细胞处于快速增殖阶段。结论：酶消化结合Nycodenz密度梯度离心法分离培养大鼠胰腺星状细胞纯度高,重复性好,可以满足体外研究的需要。     

上皮间质转化与肝细胞癌肺转移的相关性研究

目的 研究上皮间质转化和肝细胞癌肺转移的关系.方法 2000年1月至2004年3月于中山医院肝外科手术病理诊断为肝细胞癌的患者中,根据术后随访期内有无肺转移分为有肺转移组和无远处转移组,每组随机选择50例患者的原位肝癌组织制成组织芯片.用免疫组织化学染色(二步法)方法检测组织芯片上肺转移组和无远处转移组患者的肝痛组织的上皮间质转化的标志(E-cadherin、Vimentin、Fibronectin),单因素和多因素分析这些标志和肝细胞癌肺转移的关系.结果 单因素分析了性别、年龄、HbsAg、甲胎蛋白(AFP)、肿瘤大小、数目、癌栓、包膜、肝门淋巴结、肿瘤分化程度、E-钙黏蛋白(E-cadherin)、波形蛋白(Vimentin)、纤维连接蛋白(Fibroneetin)的表达与肺转移的相关性,结果显示:患者AFP水平>400 ng/ml、肿瘤直径>10 cm、门静脉癌栓、分化程度低、E-cadherin的低表达、Fibronectin的高表达、Vimentin的高表达与肝细胞癌肺转移相关;多因素分析显示肿瘤直径>10 cm、门静脉癌栓、分化程度低、Fibronectin高表达是肝细胞癌肺转移的危险因素.结论 肝细胞癌患者肝癌组织的上皮间质转化与其发生肺转移有密切关系.     

肾小管上皮间充质转化细胞模型中WT1和Pax2重新表达的研究

目的:探讨肾小管上皮间充质转化(EMT)细胞模型中胚胎发育基因WT1和Pax2的重新表达及其规律,并研究上调表达外源性WT1对肾小管上皮细胞株(NRK52E)的影响。方法:采用10 ng/ml IL-1α刺激体外培养的NRK52E细胞,建立EMT细胞模型。采用脂质体转染技术,将pRc/CMV-D-WT1质粒瞬时转染NEK52E细胞。分别提取EMT细胞模型和质粒转染组不同时间点细胞的RNA和蛋白质,采用RT-PCR和Western blot检测NEK52E细胞WT1、Pax2、上皮细胞标志E-cadherin和间充质标志α-SMA的表达,研究基因表达的时效性变化规律,并观察细胞的形态。结果:成功建立EMT细胞模型,该模型中E-cadherin的表达显著减少,α-SMA的表达显著增多,细胞发生明显的成纤维化样改变。在EMT细胞模型中,出生后关闭的WT1和Pax2获得重新表达,且Pax2的表达早于α-SMA和WT1。在NEK52E细胞中上调表达WT1,细胞表达α-SMA,不表达Pax2,同时E-cadherin的表达显著减少,细胞出现成纤维化样改变。结论:Pax2和WT1基因是EMT中的关键基因,在EMT发生时呈序列启动,Pax2在EMT中处于WT1上游。胚胎发育基因WT1和Pax2的重新表达可能是EMT的重要机制。     

Role of β-catenin signaling pathway in the epithelial to mesenchymal transition induced by parathyroid hormone in renal tubular epithelial cells

Objective To investigate the effect of parathyroid hormone (PTH) on the epithelial to mesenchymal transition (EMT) in human renal proximal tubular epithelial cells (HK-2 cells), and determine the role of β-catenin signaling pathway. Method The expression of α-smooth muscle actin (α-SMA), E-cadherin and β-catenin in HK-2 cells was measured by real-time PCR, Western blotting and immunofluorescence technique. The signaling pathway by which PTH activated EMT in HK-2 cells was identified by using synthetic β-catenin siRNA. Results Parathyroid hormone (10-10 mol/L) increased α-SMA expression and decreased E-cadherin expression in HK-2 cells (P＜0.01, respectively). Untreated cells showed the expression of E-cadherin, whereas α-SMA staining was noticeably increased in cells treated with PTH. β-catenin activity was significantly increased after exposed to PTH. Theα-SMA expression was decreased strongly and E-cadherin expression was increased after β-catenin siRNA transfection (all P＜0.05). Conclusion PTH significantly induces epithelial to mesenchymal transition in HK-2 cells throughβ-catenin signaling pathway.     

LeftyA真核表达载体的构建及其对转化生长因子-β1诱导人肾小管上皮细胞转分化的影响

目的 构建pcDNA3.1-LeftyA真核表达载体,观察其对转化生长因子-β1(TGF-β1)诱导人肾小管上皮细胞(HK-2)转分化(EMT)的影响.方法 基因克隆技术构建pcDNA3.1-LeftyA真核表达载体,将其瞬时转染HK-2细胞,TGF-β1(10μg/L)刺激后,观察细胞形态变化,检测E-钙黏蛋白(E-cadherin)、α-平滑肌肌动蛋白(α-SMA)基因及蛋白的表达.结果 TGF-β1刺激后HK-2细胞内E-cadherin mRNA和蛋白时间依赖性表达下调,α-SMA mRNA和蛋白时间依赖性表达上调,同时E-cadherin表达变化早于α-SMA;LeftyA蛋白可以显著抑制E-cadherin蛋白的下调表达(P＜0.05),其表达比同时间点单纯刺激组高17.6%;同时可逆转α-SMA蛋白的上调表达(P＜0.05),其蛋白表达比单纯刺激组低14.0%.结论 LeftyA蛋白可以抑制TGF-β1所致的EMT.

Abstract：

Objective To construct the eukaryotic expression vector for LeftyA and study the effects of LeftyA on epithelial to mesenchymal transition of human proximal tubular epithelial cells induced by transforming growth factor-β1 ( TGF-β1 ). Methods The pcDNA3. 1-LeftyA was constructed by recombinant DNA technique. After transfection with pcDNA3. 1-LeftyA HK-2 cells were stimulated by TGF-β1( 10 μg/L). The morphological changes, and the expression of E-cadherin, α-SMA and LeftyA mRNA and protein were observed and detected, respectively. Results TGF-β1 could markedly decrease the expression of E-cadherin mRNA and protein in HK-2 cells induced, and dramatically increase the expression of α-SMA mRNA and protein in a time-dependent manner. Forced expression of exogenous LeftyA led to a blockage of TGF-β1 -induced E-cadherin ( 17.6% ) suppression and α-SMA induction ( 14. 0% ). Conclusion Disruption of cell adherence is the beginning stage of EMT, and overexpression of LeftyA can suppress EMT induced by TGF-β1, which suggests a alprostadil role for LeftyA in TGF-β1-induced tubular EMT and renal fibrosis.     

CIP4对转化生长因子β1诱导的人肾小管上皮细胞-间充质转分化的影响

目的 观察骨架调节蛋白CIP4（Cdc42 interacting protein 4）对转化生长因子β1（TGF-β1）诱导的人肾小管上皮细胞-间充质转分化（EMT）的影响,并探讨其产生的机制。 方法 10 ?滋g/L TGF-β1刺激72 h诱导人近端肾小管上皮细胞（HK-2细胞）向间充质转分化。Western印迹法检测各组细胞内E-cadherin和α-SMA蛋白的表达。倒置显微镜观察细胞形态的变化。根据GenBank人CIP4的完全cDNA序列,设计1条特异性干扰CIP4表达的RNA片段（CIP4-siRNA）和含野生型CIP4的重组真核表达质粒（pcDNA3.1-hCIP4）,利用lipofactamine 2000将其转染HK-2细胞。Western 印迹法检测对照组、TGF-β1刺激组、CIP4-siRNA转染组、pcDNA3.1-CIP4转染组细胞内CIP4、E-cadherin和α-SMA蛋白的表达,共聚焦显微镜观察 E-cadherin和α-SMA蛋白的分布改变;用PI3K-Akt特异性抑制剂渥曼青霉素（wortmannin） 1 μmol/L干预TGF-β1刺激的HK-2细胞48 h,Western 印迹法检测对照组和干预组CIP4表达的变化。 结果 TGF-β1干预后HK-2细胞E-cadherin蛋白表达显著减少（P ＜ 0.05）,α-SMA蛋白表达显著增多（P ＜ 0.05）,细胞形态由典型的上皮细胞向肌成纤维细胞转变,表明TGF-β1诱导肾小管上皮细胞EMT模型成功。CIP4-siRNA抑制TGF-β1诱导的HK-2细胞表达CIP4后,E-cadherin蛋白表达显著增多（P ＜ 0.05）,α-SMA蛋白表达显著减少（P ＜ 0.05）,部分逆转了上述TGF-β1诱导的肾小管上皮细胞EMT。pcDNA3.1-hCIP4转染使CIP4高表达后,HK-2细胞E-cadherin蛋白表达显著减少（P ＜ 0.05）,α-SMA蛋白表达显著增多（P ＜ 0.05）,诱导了肾小管上皮细胞EMT。用渥曼青霉素干预TGF-β1刺激的HK-2细胞48 h,CIP4可能蛋白表达显著减少（P ＜ 0.05）。 结论 TGF-β1通过PI3K-Akt途径上调CIP4表达,CIP4可能进一步参与TGF-β1诱导的肾小管上皮细胞EMT过程。     

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.     

Albumin-induced epithelial mesenchymal transformation

Background: Progressive chronic kidney disease is often associated with albuminuria and renal fibrosis linked to the accumulation of myofibroblasts producing extracellular matrix. Renal myofibroblasts are derived from a number of cells including tubular epithelial cells (TECs) through epithelial mesenchymal transformation (EMT). This study explores the hypothesis that exposure of TECs to albumin induces EMT. Methods: Normal rat TECs (NRK52E) were exposed in culture to de-lipidated bovine serum albumin (dBSA; 10 mg/ml) for 2, 4 and 6 days. Binding/uptake of fluoresceined albumin by PTCs was evaluated. Transformation into myofibroblasts was assessed by light and electron microscopy, immunofluorescence and Western blotting for α-smooth muscle actin (α-SMA), E-cadherin and transforming growth factor-β1 (TGF-β1). We also investigated the expression of fibroblast-specific protein-1 (FSP-1) and collagens I, III and IV. TGF-β1 biological activity, mRNA and protein were measured. A neutralising anti-TGF-β1 antibody was used to analyse the role of TGF-β1 in albumin-induced EMT. Results: Exposure of TECs to dBSA led to binding/uptake of albumin as well as fibroblastic morphological changes. Incubation of TECs with dBSA caused a reduction of TEC marker E-cadherin (ANOVA p = 0.0002) and de novo expression of fibroblast markers α-SMA and FSP-1 (ANOVA p = 0.0001) in a time-dependent manner. It also increased expression and activity of TGF-β1. Neutralisation of TGF-β1 significantly reduced EMT (p < 0.01). Conclusion: This study demonstrates that in vitro, albumin induces the transformation of TECs into cells with myofibroblast characteristics; a process that may be TGF-β1 dependent.     

Role of JLP on the epithelial to mesenchymal transition in renal tubular epithelial cells

Objective To observe the effect of JLP on transdifferentiation of human renal proximal tubular epithelial cells (HK-2), and to investigate the role of p38 MAPK signaling pathway in this process. Methods The knock-down plasmids of JLP were constructed. HK-2 cells were randomly divided into four groups: negative control cells (Ctrl-shRNA group), knock-down jlp cells (jlp-shRNA group), negative control cells with FGF-2 treatment (FGF-2 group) and knock-down jlp cells with FGF-2 treatment(jlp-shRNA+FGF-2 group). The expressions of JLP, E-cadherin, TGF-β1, α-SMA, p-p38 MAPK protein were detected by Western blotting．After the induction of FGF-2 for 24 hours, the expressions of α-SMA, COL-I, FN were detected by immunocytochemistry. Results Compared with Ctrl-shRNA group, the expression of JLP protein was significantly down-regulated in FGF-2 group. Compared with FGF-2 group, the expressions of TGF-β1, α-SMA, p-p38 MAPK protein were significantly up-regulated, while E-cadherin protein was significantly down-regulated (P＜0.05). Compared with FGF-2 group, the expressions of α-SMA, COL-I, FN immunostaining increased markedly in jlp-shRNA+FGF-2 group. Conclusion Scaffolding protein JLP is critical in preventing EMT in the course of fibrosis through the inhibition of p-p38 activation in HK-2 cells.     

热休克蛋白72肽结合区对肾小管上皮间质转分化的影响

目的 探讨热休克蛋白72肽结合区在肾小管上皮间质转分化(EMT)过程中的作用和可能机制.方法 应用质粒转染方法分别诱导热休克蛋白72(HSP72)野生型、肽结合区缺失型(HSP72-△PBD)和肽结合区(PBD)的表达.用转化生长因子β1(TGF-β1)刺激大鼠肾小管上皮细胞(NRK-52E)48 h,Western印迹和免疫荧光染色检测细胞E-钙黏蛋白(cadherin),α-平滑肌肌动蛋白(SMA),HSP72和Smad3/磷酸化(p)-Smad3蛋白表达.结果 TGF-β1(10 μg/L)刺激NRK-52E细胞48 h后上调α-SMA和下调E-cadherin蛋白表达水平.Western印迹及细胞免疫荧光显示,过表达HSP72和PBD能明显减轻TGF-β1诱导的NRK-52E细胞E-cadherin蛋白表达下调和α-SMA蛋白表达上调,而过表达HSP72-△PBD不能改变上述蛋白的表达.此外,过表达HSP72和PBD显著抑制Smad3的磷酸化.结论 HSP72抑制Smad3活化和EMT的发生可能与PBD的功能有关.     

NF-κB通路在单核细胞诱导肾小管上皮细胞转分化中的作用

目的 观察单核细胞（U937细胞）对人近端肾小管上皮细胞（HK-2细胞）转分化的影响及其分子机制。 方法 将HK-2细胞与人单核细胞系U937细胞共培养;倒置相差显微镜观察HK-2细胞形态;Western印迹、实时荧光定量PCR法检测α平滑肌肌动蛋白（α-SMA）、纤连蛋白（FN）、E钙黏蛋白（E-cadherin）和胞间黏附分子1（ICAM-1）表达;BCECF-AM荧光染色法测定单核细胞黏附;流式细胞仪法检测HK-2细胞表面分子ICAM-1表达;基因芯片筛选HK-2细胞基因变化;利用信号阻断剂阻断基因芯片筛选出的信号通路,进一步验证单核细胞诱导肾小管上皮细胞转分化的分子机制。 结果 单核细胞可直接诱导HK-2细胞发生形态变化,减少HK-2细胞E-cadherin表达（均P < 0.05）,并上调α-SMA、FN表达（均P < 0.05）。应用CD18抗体阻断CD18-ICAM-1可抑制单核细胞黏附及其诱导的HK-2细胞形态变化。基因芯片结果显示,NF-κB信号通路分子CC亚族趋化因子配体20（CCL20）、白细胞介素（IL）2、IL-8、脂磷壁酸（LTA）及血小板内皮细胞黏附分子1（PECAM1）表达明显增加（均P < 0.05）。NF-κB信号阻断剂吡咯烷二硫氨基甲酸（PDTC）能显著抑制HK-2细胞形态变化及表面ICAM-1表达,抑制单核细胞诱导的肾小管上皮细胞转分化。 结论 单核细胞通过CD18分子与HK-2细胞表面ICAM-1结合,从而启动NF-κB信号通路介导的特定基因转录,最终导致肾小管上皮细胞发生转分化。     

囊泡型H+-ATP酶B亚基在转化生长因子β1致肾小管上皮细胞转分化中的变化及其意义

目的 探讨在转化生长因子（TGF）β1致大鼠肾小管上皮细胞（NRK52E）发生上皮细胞向间质细胞转分化（EMT）过程中囊泡型H+-ATP酶（V-ATPase）B亚基的变化及其可能意义。 方法 NRK52E细胞无血清培养后予TGF-β1（10 μg/L）刺激不同时间（0、6、12、24、48、72 h）,应用实时定量PCR、Western印迹、免疫荧光技术检测?琢平滑肌肌动蛋白（?琢-SMA）、E钙黏素（E-cadherin）、V-ATPase B亚基（B1、B2）mRNA、蛋白表达及分布的变化。 结果 TGF-β1刺激NRK52E细胞48 h后?琢-SMA mRNA及蛋白表达显著上调,E-cadherin mRNA及蛋白表达显著下调,同时V-ATPase B2亚基mRNA及蛋白表达也显著增加（均P < 0.05）。但是B1亚基在细胞内表达很低,刺激后也未见显著变化。免疫荧光也显示V-ATPase B2亚基在细胞内的分布明显增加并向胞膜聚集。 结论 在NRK52E内主要分布的是V-ATPase B2亚基。TGF-β1刺激NRK52E EMT过程中V-ATPase B2亚基表达显著增加,这提示B2亚基可能参与肾小管EMT过程。