Retrograde transport of Shiga toxin 1 in human renal tubular epithelial cells

To displays its cytotoxicity by initiating RNA cleavage, Stx1 is required to be transported from endosomes to the endoplasmic reticulum, where the translocation of the A-subunit to the cytosol occurs. In the case of established cell lines, it is reported that a large proportion of the internalized Stx is transported to lysosomes for degradation and only a fraction of the toxin molecules can reach to the cytosol. By using primary culture cells, however, we observed that Stx1 is effectively delivered to the cytosol in normal human renal tubular epithelial cells. Investigation of retrograde transport mechanism of Stx should provide insights into the analysis of Stx-mediated cell damage and lead to improvements in therapeutic approaches for diseases caused by Stx.     

miR-204-3p靶向CYP2E1介导脂多糖诱导的肾小管上皮细胞损伤

目的探讨miR-204-3p靶向细胞色素P450家族2亚家族E成员1(CYP2E1)介导脂多糖(LPS)诱导的肾小管上皮细胞炎症反应及细胞凋亡的分子机制。方法体外培养人肾小管上皮细胞HK-2,qRT-PCR与Western blot分别检测miR-204-3p、CYP2E1的表达量;实验分组:Con组、LPS组、LPS+miR-NC组、LPS+miR-204-3p组、LPS+si-NC组、LPS+si-CYP2E1组、LPS+miR-204-3p+pcDNA组、LPS+miR-204-3p+pcDNA-CYP2E1组;ELISA检测IL-6、TNF-α的水平;流式细胞术检测细胞凋亡率;双荧光素酶报告实验验证miR-204-3p与CYP2E1的靶向结合关系;Western blot检测Bcl-2、Bax的表达量。结果与Con组比较,LPS组细胞中miR-204-3p的表达水平降低,CYP2E1的表达量升高,IL-6、TNF-α的水平升高,凋亡率和Bax蛋白水平升高,Bcl-2蛋白水平降低,差异有统计学意义(P<0.05);与LPS+miR-NC组比较,LPS+miR-204-3p组IL-6、TNF-α水平降低,凋亡率和Bax蛋白水平降低,Bcl-2蛋白水平升高,差异有统计学意义(P<0.05);与LPS+si-NC组比较,LPS+si-CYP2E1组IL-6、TNF-α的水平降低,凋亡率和Bax蛋白水平降低,Bcl-2蛋白水平升高,差异有统计学意义(P<0.05);双荧光素酶报告实验证实miR-204-3p能够靶向结合CYP2E1;与LPS+miR-204-3p+pcDNA组比较,LPS+miR-204-3p+pcDNA-CYP2E1组IL-6、TNF-α的水平升高,凋亡率和Bax蛋白水平升高,Bcl-2蛋白水平降低,差异有统计学意义(P<0.05)。结论 miR-204-3p过表达可靶向调控CYP2E1的表达从而抑制LPS诱导的肾小管上皮细胞炎症反应及细胞凋亡。     

转化生长因子β1抑制人肾小管上皮细胞的增殖

背景：慢性肾衰竭进展过程中的一个重要病理改变是炎症和纤维化,主要包括肾小球和肾小管的炎症和纤维化。目前大多数研究主要集中于肾小球,对于肾小管病变的研究相对较少。但实际上部分疾病的肾小管病变出现在肾小球病变之前,其对于疾病预后更具有指导意义。目的：观察转化生长因子β1对人类肾小管上皮细胞HK-2增殖的影响,探索转化生长因子β1在肾小管炎症和纤维化方面的作用。方法：将传代培养的HK-2细胞分成空白对照组和转化生长因子β1作用组,分别使用DMEM／F12培养液,以及含转化生长因子β1（2,5,10#g／L）的DMEM／F12培养液培养,在倒置显微镜下观察各组细胞形态的改变,并使用MTT法检测细胞增殖情况。结果与结论：转化生长因子β1能显著抑制人。肾小管上皮细胞的增殖,并促使细胞向纤维样改变,与空白对照组相比差异有显著性意义（P〈0．05）,其抑制增殖作用并不随转化生长因子β1质量浓度的增大而显著增强,作用时间可持续至72h。结果可见转化生长因子β1能够抑制人肾小管上皮细胞的增殖,并具有促进肾间质纤维化的作用。     

转化生长因子β1对大鼠肾小管上皮细胞中基质细胞衍生因子1表达的影响

目的:已知转化生长因子β1与肾脏组织纤维化形成有密切关系.拟进一步探讨转化生长因子β1对大鼠近端肾小管上皮细胞(NRK52E)中基质细胞衍生因子1表达的影响.方法:实验于2006-03/2007-05在四川大学生物治疗国家重点实验室神经分子生物实验室完成.①实验材料:大鼠近端肾小管上皮细胞株NRK52E,由澳大利亚Monash医学中心肾内科实验室提供;转化生长因子β 1由cytolab公司提供.②实验分组:将大鼠近端肾小管上皮细胞分为正常对照组:无转化生长因子β1干预;实验组:又分为在同一转化生长因子β1浓度(2μ g/L)下,培养6,12,24 h;在不同的转化生长因子β1浓度(2,5,10 μ g/L)下,培养24 h.③利用免疫细胞化学技术对同一转化生长因子β1浓度(2 μ g/L)干预不同时间后的大鼠近端肾小管上皮细胞中基质细胞衍生因子1的蛋白表达进行半定量分析,选择出最佳的作用时间点;通过反转录-聚合酶链反应、Western-Blotting以检测大鼠近端肾小管上皮细胞中基质细胞衍生因子1在不同转化生长冈子β1浓度干预下培养24 h后的mRNA、蛋白表达变化情况.结果:①培养12,24h时,大鼠近端肾小管上皮细胞中基质细胞衍生因子1的蛋白表达比0h增高(P＜0.05);24h时表达略高于12h(P＞0.05).提示,基质细胞衍生因子1的表达到达一_甲台期,24h为最佳的作用时间点.②从mRNA水平和蛋白水平均证实,2 μ g/L转化生长因子β 1干预24 h后的大鼠近端肾小管上皮细胞中基质细胞衍生因子1的表达高于正常对照组(P＜0.05):随着转化生长因子β1的浓度增大,表达呈下降趋势,10 μ g/L时表达低于2 μ g/L时的表达(P＜0.05).结论:基质细胞衍生因子1在正常的大鼠近端肾小管上皮细胞中呈低表达状态,对转化生长因子β1的干预表现出一定的时间、剂量依赖性,基质细胞衍生因子1可能参与了肾问质纤维化的发生、发展.     

Endonuclease-induced DNA damage and cell death in oxidant injury to renal tubular epithelial cells.

Hydrogen peroxide (H2O2)-induced DNA damage and cell death have been attributed to the direct cytotoxicity of H2O2 and other oxidant species generated from H2O2. We examined the possibility that oxidants activate endonucleases leading to DNA damage and cell death in renal tubular epithelial cells, similar to that described for apoptosis. Within minutes, H2O2 caused DNA strand breaks in a dose-dependent manner, followed by cell death. DNA fragmentation was demonstrated both by the release of [3H]thymidine in 27,000-g supernatant as well as the occurrence of low molecular weight DNA fragments on agarose gel electrophoresis, characteristic of endonuclease cleavage. Endonuclease inhibitors, aurintricarboxylic acid, Evans blue, and zinc ion prevented H2O2-induced DNA strand breaks, fragmentation, and cell death. Inhibitors of protein or mRNA synthesis had only minor protection against H2O2-induced DNA damage in contrast to complete protection reported in apoptotic thymocytes. Micrococcal endonuclease induced similar DNA strand breaks in LLC-PK1 cells, and the endonuclease inhibitors prevented the events confirming the ability of endonucleases to induce DNA damage. The protective effect of aurintricarboxylic acid was not due to the prevention of the rise in intracellular free calcium. We conclude that endonuclease activation occurs as an early event leading to DNA damage and cell death in renal tubular epithelial cells exposed to oxidant stress and, in contrast to apoptotic thymocytes, does not require macromolecular synthesis.     

体外诱导骨髓间充质干细胞向肾小管上皮细胞的分化

目的:探讨体外诱导骨髓间充质干细胞向肾小管上皮细胞分化的可行性。方法:实验于2004-10/2005-12在苏州大学儿科研究所和苏州大学附属儿童医院骨科实验室完成。骨髓间充质干细胞特性实验:①将2只4周龄SD大鼠断颈处死,无菌条件下取股骨、胫骨,去除其干骺端,暴露骨髓腔,DMEM培养液冲洗,混匀后用密度为1.077g/L淋巴细胞分离液分离。取单个核细胞层接种50mL细胞培养瓶进行培养,3d后首次换液,待10～14d细胞生长到80%～90%融合时以胰蛋白酶-乙二胺四乙酸消化传代。②采用免疫荧光法测定骨髓间充质干细胞表面CD44与Vimentin的表达情况;应用二苯基四氮唑溴盐法检测细胞生长情况。损伤肾脏组织匀浆诱导骨髓间充质干细胞实验:①取1只成年SD大鼠麻醉后,表皮消毒,取腹部正中切口,寻及双侧肾蒂,用无损伤动脉夹夹闭双侧肾蒂,缺血60min后松开动脉夹,再灌注60min后,无菌取肾制备匀浆。②将肾脏匀浆置于插入式嵌合培养皿中对第3代骨髓间充质干细胞进行诱导,并加入含有5μmol/L全反式维甲酸的最低必须培养基。③诱导第0,3,5,7天,倒置显微镜下观察细胞大体形态变化;以上各时间点取活细胞制成活细胞悬液,经流式细胞仪测定第18型角蛋白的阳性表达率;取诱导分化第7天的细胞,电镜观察其超微结构变化;钙钴法碱性磷酸酶细胞化学染色,与未经损伤肾脏组织匀浆诱导的骨髓间充质干细胞进行比较。结果:①骨髓间充质干细胞的特性检测:免疫荧光法鉴定分离培养的第3代细胞表面CD44和Vimentin表达阳性。二苯基四氮唑溴盐法测得的细胞生长曲线呈倒“S”型。②损伤肾脏组织匀浆诱导后骨髓间充质干细胞情况:骨髓间充质干细胞经诱导后大体形态变圆,由梭形细胞逐渐转变为鹅卵石样细胞,细胞碱性磷酸酶染色呈强阳性。诱导第7天细胞出现微绒毛和紧密连接,经诱导后的骨髓间充质干细胞第18型角蛋白表达阳性率升至79.5%。结论:在缺血再灌注损伤大鼠肾脏匀浆及全反式维甲酸的联合诱导下,骨髓间充质干细胞可向肾小管上皮样细胞分化,具有成为种子细胞应用于急性肾脏损伤治疗的潜在价值。     

Possible reason for preferential damage to renal tubular epithelial cells evoked by amphotericin B.

An important determinant of nephrotoxicity, which is the major complication of long-term amphotericin B treatment, is dysfunction of distal tubular epithelial cells. The underlying cause for this rather selective damage to the cells is unknown. In the present investigation, it was shown that kidney epithelial cells were initially damaged by amphotericin B at concentrations of 2.5 to 10 micrograms/ml, as demonstrable by a dramatic drop in cellular K+ levels. Cells could recover from the initial toxic action of the polyene if they were kept in medium of neutral pH, and cellular K+ levels returned to normal after 6 h. However, the recovery mechanisms failed at lower pHs of 5.6 to 6.0. At low pHs, cells became progressively depleted of ATP; they leaked lactate dehydrogenase and became irreversibly damaged after approximately 6 h. The possibility that the low pH characteristic of the distal tubulus lumen renders the renal epithelial cells particularly vulnerable to the toxic action of amphotericin B is raised. The concept is in line with an earlier report that alkalization ameliorates amphotericin B nephrotoxicity in rats.     

缺血-再灌注急性肾损伤后原位成人干/祖细胞参与肾小管上皮细胞再生

目的对急性肾损伤(AKI)模型大鼠肾小管损伤部位肾原位成人干/祖细胞(ARPC)的动态改变进行观察,探讨ARPC对AKI肾小管再生修复的影响。方法雄性SD大鼠右侧肾切除同时左侧肾动脉夹闭45 min建立缺血-再灌注肾损伤模型(AKI组),设假手术组为对照组(Sham组)。AKI组分别于设定时间处死动物,采集血及肾脏标本,检测血肌酐(Scr)、尿素氮(BUN),行HE染色观察肾脏病理改变,观察肾小管损伤和修复。免疫荧光染色及激光共聚焦显微镜观察ARPC标记蛋白CD24+CD133+在肾组织的表达。结果 AKI组术后短时间内Scr、BUN即迅速升高[Scr:(124.74±6.93)μmol/L;BUN:(18.27±2.38)mmol/L],第3天达高峰[Scr:(228.32±24.76)μmol/L;BUN:(26.32±3.93)mmol/L],随后缓慢降低,Sham组保持在正常水平。第7天后逐渐下降至正常,第14天肾功能基本恢复正常。光镜下可见AKI早期(第1天)肾小管上皮细胞呈灶性坏死、小管浊肿,管腔面微绒毛消失,部分刷状缘脱落,肾间质水肿使小管间隙扩大;第3~7天病变范围扩大,程度加重,部分小管空泡变性,脱落、坏死,形成蛋白管型,部分基底膜裸露。1周后在肾小管损伤部位出现再生的上皮细胞,细胞呈扁平样,细胞核大小不等,排列紊乱。免疫荧光结果显示,AKI早期仅见少许CD24+CD133+细胞,3~5 d后损伤肾小管处出现较多CD24+CD133+细胞[(7.5±2.1)个/视野,(8.3±1.7)个/视野],持续至第14天仍可见较多阳性细胞[(2.2±1.3)个/视野],与Sham组(d0)比较,差异具有统计学意义(P<0.05,P<0.01)。结论肾缺血-再灌注可引起急性肾小管坏死损伤,但肾小管上皮细胞可通过再生而迅速修复,肾脏结构和功能再建;此过程中ARPC激活并持续表达,可能参与肾小管再生。     

骨髓干细胞移植对急性缺血性肾损伤大鼠肾小管细胞活性的影响

目的观察和分析骨髓干细胞(BMSCs)移植对大鼠急性缺血性肾损伤后肾小管上皮细胞坏死、变性及增殖的影响。方法 Percoll密度梯度离心法分离获取BMSCs。制作大鼠急性缺血性肾损伤模型,通过下腔静脉进行BMSCs移植。分别于缺血再灌注后24h、48h、7d、14d获取肾脏标本,HE染色作肾组织学观察,免疫组织化学染色检测增殖细胞核抗原(PCNA)的表达。结果缺血再灌注后24h、48h,BMSCs移植组肾小管上皮细胞未见坏死及明显变性,而对照组细胞坏死及变性明显;缺血再灌注后7d、14d,BMSCs移植组和对照组肾小管上皮均无细胞坏死,但对照组可见部分细胞胞浆肿胀及间质内少许红细胞;BMSCs移植组较对照组肾小管上皮PCNA阳性细胞数增多,组间差异具统计学意义。结论 BMSCs移植可减少急性缺血性肾损伤的肾小管上皮细胞变性、坏死,而促进肾小管上皮细胞的增殖。     

不同方式透析前、后尿毒症血清对肾小管上皮细胞TGF-β1表达的影响

目的探讨不同方式透析前、后尿毒血清对肾小管上皮细胞TGF-β1表达的影响。方法24例尿毒症透析患者随机分为血液透析（HD）、高通量血液透析（HFHD）、血液透析滤过（HDF）三组,分别于透析前后取患者血清,二乙酰一肟法测定透析前后尿素比值,评价三种透析方式的充分性;用透析前后患者血清刺激体外培养的肾小管上皮细胞株（HK-2细胞）,然后用RT-PCR法检测HK-2细胞TGF-β1 mRNA表达,ELISA法检测HK-2细胞培养上清TGF-β1水平。结果三种透析方式的Kt/V值均大于1.2,达到充分透析的要求;HDF组透析后尿毒血清较透析前血清促HK-2细胞表达和分泌TGF-β1的作用减弱（P〈0.05）;而HD和HFHD组透析后与透析前比较,差异无统计学意义（P〉0.05）。结论HDF能更有效地清除尿毒血清中致前纤维化细胞因子表达的毒素,由此推测HDF可能更有效地延缓尿毒症患者肾间质纤维化的进展。     

骨髓间充质干细胞体内分化为肾小管上皮细胞的实验研究

目的探讨骨髓间充质干细胞(mesenchymal stem cells,MSCs)能否在体内分化为肾小管上皮细胞。方法取SD雄性大鼠胫、股骨骨髓,密度梯度离心法分离MSCs,采用4,6-联脒-2-苯基吲哚(4,6-diamidino-2-phenylindole,DAPI)进行标记。32只雌性SD大鼠复制缺血再灌注肾损伤模型后随机分为移植组和对照组,移植组于缺血45min后经下腔静脉注入用DAPI标记的MSCs,对照组注入等量的生理盐水。分别于术后1d、2d、3d、4d处死大鼠,留取肾组织,荧光显微镜观察移植的MSCs在肾组织中的分布,采用能与肾小管内腔壁特异结合的蓖麻血凝素(Ricinus communis agglurinin,RCA)对迁移入肾脏的MSCs分化状况进行鉴定。结果移植组术后第三天肾组织内可见DAPI标记细胞,第四天DAPI标记细胞明显增多(P<0.05),且多数DAPI标记细胞能结合RCA。对照组没有发现DAPI标记细胞。结论移植的外源性MSCs能够迁移、定居于肾组织中并分化为肾小管上皮细胞。     

移植肾间质纤维化和小管萎缩与肾小管上皮间充质转化的关系

目的:观察移植肾间质纤维化和小管萎缩病变与肾小管上皮间充质转化的关系.方法:选择38例同种异体肾移植术后9个月的患者,检测肾功能,移植肾行穿刺活检,按照Banff 1997慢性评分标准分为2组:第1组和第2组.然后取病理切片进行各项免疫组化检测,观察间质内细胞角蛋白、波形蛋白、α-平滑肌肌动蛋白的表达情况,并行比较分析.结果:第1组有22例患者,第2组有16例.两组的一般临床资料差异无显著性;第2组血肌酐高于第1组,但差异无显著性(P＞0.05).第1组中细胞角蛋白阳性表达率高于第2组;而第2组中波形蛋白、α-平滑肌肌动蛋白表达率高于第1组,差异均有显著性(P＜0.05).结论:在移植肾间质纤维化和小管萎缩过程中,上皮间充质转化与其有明显的相关性;同时出现较高表达的波形蛋白和α-平滑肌肌动蛋白,提示纤维化程度较重.     

骨髓间充质干细胞体内分化为肾小管上皮细胞的实验研究

目的 探讨骨髓间充质干细胞(mesenchymal stem cells,MSCs)能否在体内分化为肾小管上皮细胞.方法 取SD雄性大鼠胫、股骨骨髓,密度梯度离心法分离MSCs,采用4,6-联脒-2-苯基吲哚(4,6-diamidino-2-phenylindole,DAPI)进行标记.32只雌性SD大鼠复制缺血再灌注肾损伤模型后随机分为移植组和对照组,移植组于缺血45min后经下腔静脉注入用DAPI标记的MSCs,对照组注入等量的生理盐水.分别于术后1 d、2 d、3 d、4 d处死大鼠,留取肾组织,荧光显微镜观察移植的MSCs在肾组织中的分布,采用能与肾小管内腔壁特异结合的蓖麻血凝素(Ricinus communis agglurinin,RCA)对迁移入肾脏的MSCs分化状况进行鉴定.结果 移植组术后第三天肾组织内可见DAPI标记细胞,第四天DAPI标记细胞明显增多(P＜0.05),且多数DAPI标记细胞能结合RCA.对照组没有发现DAPI标记细胞.结论 移植的外源性MSCs能够迁移、定居于肾组织中并分化为肾小管上皮细胞.     

Pkd1 regulates immortalized proliferation of renal tubular epithelial cells through p53 induction and JNK activation

Autosomal dominant polycystic kidney disease (ADPKD) is the most common human monogenic genetic disorder and is characterized by progressive bilateral renal cysts and the development of renal insufficiency. The cystogenesis of ADPKD is believed to be a monoclonal proliferation of PKD-deficient (PKD(-/-)) renal tubular epithelial cells. To define the function of Pkd1, we generated chimeric mice by aggregation of Pkd1(-/-) ES cells and Pkd1(+/+) morulae from ROSA26 mice. As occurs in humans with ADPKD, these mice developed cysts in the kidney, liver, and pancreas. Surprisingly, the cyst epithelia of the kidney were composed of both Pkd1(-/-) and Pkd1(+/+) renal tubular epithelial cells in the early stages of cystogenesis. Pkd1(-/-) cyst epithelial cells changed in shape from cuboidal to flat and replaced Pkd1(+/+) cyst epithelial cells lost by JNK-mediated apoptosis in intermediate stages. In late-stage cysts, Pkd1(-/-) cells continued immortalized proliferation with downregulation of p53. These results provide a novel understanding of the cystogenesis of ADPKD patients. Furthermore, immortalized proliferation without induction of p53 was frequently observed in 3T3-type culture of mouse embryonic fibroblasts from Pkd1(-/-) mice. Thus, Pkd1 plays a role in preventing immortalized proliferation of renal tubular epithelial cells through the induction of p53 and activation of JNK.     

草酸钙晶体对大鼠肾小管上皮细胞骨桥蛋白表达的影响

目的探讨一水草酸钙(calcium oxalate monohydrate,COM)晶体对大鼠肾小管上皮细胞中骨桥蛋白(osteopontin,OPN)表达的影响。方法选用SD大鼠的肾皮质原代培养出肾小管上皮细胞并制成爬片,将爬片的肾小管上皮细胞随机分为A、B、C、D、E5组。A组不加COM(11例);B组1 mmol/L浓度COM(17例);C组3 mmol/L浓度COM(18例);D组5 mmol/L浓度COM(18例);E组10 mmol/L浓度COM(17例)。采用免疫组织化学法(SABC)检测各组肾小管上皮细胞中OPN的表达,并进行阳性细胞计数和各组间比较。结果 OPN的表达主要定位于细胞质,呈棕褐色。各组OPN阳性表达率:A组54.5%;B组64.7%;C组77.8%;D组88.9%;E组76.5%。随着COM浓度增加,OPN表达逐渐增强,到5 mmol/L浓度COM时OPN表达最强(P0.01),而10 mmol/L浓度COM时OPN表达反而下降,接近3 mmol/L浓度COM水平(P0.05)。结论大鼠肾小管上皮细胞受COM刺激后OPN表达增强,但高浓度COM使OPN表达减弱,提示高浓度COM通过损伤肾小管上皮细胞使OPN表达下降,进而形成结石。