白细胞介素6刺激人近端肾小管上皮细胞α-平滑肌肌动蛋白的表达

目的观察重组人白细胞介素6（rIL-6）在体外对人近端肾小管上皮细胞（HK-2）α-平滑肌肌动蛋白（α—SMA）表达的影响。方法浓度为25ng／mL的IL-6刺激HK-2细胞,在0h、24h、48h、72h不同时间点,分别应用逆转录-聚合酶链反应（RT—PCR）、免疫荧光技术检测HK-2细胞中α—SMA mRNA及蛋白的表达。结果与刺激前比较,IL-6以时间依赖方式上调HK-2细胞α—SMA mRNA的表达、α—SMA蛋白表达逐渐增强。结论IL-6可诱导体外培养的肾小管上皮细胞表达α—SMA。     

不同病理类型肾综患者尿蛋白对肾小管上皮细胞增殖和凋亡相关蛋白Fas表达的影响

目的：观察不同病理类型肾病综合征（NS）患者尿蛋白对肾小管上皮细胞（RTECs）增殖和凋亡的影响,以进一步明确尿蛋白所致肾小管-间质损害的机制.方法：（1）从局灶-节段性肾小球硬化症（FSGS）、膜性肾病（MN）、微小病变肾病（MCN）三种不同病理类型的NS患者尿液中提取尿蛋白,经成份分析、灭菌等处理后以0.5 mg/ml、1.0 mg/ml、2 mg/ml、4 mg/ml、8 mg/ml浓度分别刺激体外培养的HK-2细胞,另设空白对照组.（2）MTT法检测不同病理类型NS患者尿蛋白刺激后细胞的增殖情况.（3）乳酸脱氢酶（LDH）释放实验检测不同病理类型NS患者尿蛋白的细胞毒作用.（4）Western Blotting法检测Fas蛋白表达.结果：各病理类型所提取的尿蛋白成分相同,主要为白蛋白、转铁蛋白、IgG等,但各病理类型组成比例不同;肾小管上皮细胞MTT值低浓度有明显增殖作用,高浓度时细胞过度增殖则导致凋亡;肾小管上皮细胞LDH释放率和Fas蛋白的表达水平随尿蛋白浓度的升高而升高;以上各项检测指标中FSGS患者尿蛋白对HK-2细胞的作用最强,MN次之,MCD最弱.结论：在体外条件下,尿蛋白对RTECs呈剂量依赖性的细胞毒作用,低剂量尿蛋白诱导RTECs异常增殖,较高剂量尿蛋白可诱导RTECs凋亡;除尿蛋白的量决定了损伤严重程度外,尿蛋白的性质也决定了损伤的严重程度.     

汉防己甲素对马兜铃酸A诱导的人近端肾小管上皮细胞转分化的干预作用

目的：探讨汉防己甲素（tetrandrine,rret）对马兜铃酸A（aristoloehic acid Ⅰ,AAⅠ）诱导的人近端肾小管上皮细胞（HK-2）转分化的拮抗效应。方法：将正常培养的HK-2随机分组：正常组、模型组、汉防己甲素高浓度组、汉防己甲素中浓度组、汉防己甲素低浓度组、泼尼松龙对照组（糖皮质激素组）。48h后观察各组细胞形态的变化,逆转录-聚合酶链式反应方法检测各组E—cadherin、TGF-β1、α-SMA mRNA表达水平,双抗体夹心酶联免疫吸附法测定各组细胞培养液中TGF-β1浓度,流式细胞技术测定各组E—cadherin阳性表达细胞的百分率。结果：汉防己甲素干预组及泼尼松龙对照组E—cadherin mRNA表达水平明显高于模型组（P〈0．05）,相反,其TGF-β1、α-SMA mRNA表达水平明显低于模型组（P〈0．05）;汉防己甲素干预组及泼尼松龙对照组TGF-β1浓度亦明显低于模型组（P〈0．05）;汉防己甲素干预组（中、低浓度）E—cadherin阳性表达细胞的百分率明显高于模型组（P〈0．05）,但汉防己甲素高浓度组和泼尼松龙对照组E—cadherin阳性表达细胞的百分率较之模型组增高不明显（P〉0．05）。结论：一定浓度（10μg／ml）的AAⅠ能诱导体外培养的HK-2转分化,适当浓度的Tet对AAi诱导的HK-2转分化具有明显的拮抗作用;AAI亦能上调TGF-β1的表达,而适当浓度的Tet能拮抗AAI引起的TGF-β1的高表达。     

氟伐他汀对晚期糖基化终产物诱导的人近端肾小管上皮细胞转分化的影响

目的：研究氟伐他汀对晚期糖基化终产物（AGE）诱导的人近端肾小管上皮细胞（HK-2）转分化的影响及核因子（NF）-κB在其中所起的作用。方法：将培养细胞分为5组：（1）BAS组;（2）AGE-BAS组;（3）AGE-BAS＋NF-κB特异性阻断剂（PDTC）组;（4）AGE-BAS＋氟伐他汀组;（5）AGE-BAS＋氟伐他汀＋PDTC组。应用EMSA法测定NF-κB活性变化。Westernblot法检测α-平滑肌肌动蛋白（α-SMA）、E-钙黏着糖蛋白（E-cadherin）表达。结果：氟伐他汀在一定浓度范围内,呈剂量依赖性抑制AGE-BSA诱导的HK-2细胞NF-κB活化。AGE-BSA刺激后随浓度增加,时间延长,α-SMA蛋白表达明显升高、E-adherin蛋白表达明显降低。NF-κB特异性阻断剂PDTC及氟伐他汀均能部分阻断AGE-BSA诱导的α-SMA蛋白表达升高及E-adherin蛋白表达降低。氟伐他汀＋PDTC进一步抑制AGE-BSA诱导的α-SMA蛋白表达升高及E-adherin蛋白表达降低。结论：NF-κB参与了AGE-BSA诱导的HK-2细胞转分化。氟伐他汀抑制HK-2细胞转分化除通过抑制NF-κB活化,可能还有其他机制。     

黏着斑激酶在转化生长因子β1诱导的人肾小管上皮细胞转分化中的作用

目的 观察转化生长因子（TGF）β1诱导的正常人近端肾小管上皮细胞（HK-2）转分化（EMT）过程中黏着斑激酶（FAK）的表达及下调FAK的表达后对TGF-β1诱导的HK-2细胞转分化进程的影响。 方法 应用TGF-β1（10 μg/L）刺激HK-2细胞,采用RT-PCR、Western印迹和免疫荧光方法分别检测E钙黏蛋白（E-cadherin）、α平滑肌肌动蛋白（α-SMA）、FAK mRNA和蛋白的表达及磷酸化（p）-FAK（Tyr397）的蛋白表达。应用Lipofectmine2000将FAK siRNA转染HK-2细胞,采用Western印迹观察下调表达FAK对上述指标的影响。 结果 TGF-β1刺激后,HK-2细胞α-SMA蛋白和mRNA水平上调,E-cadherin蛋白和mRNA表达下调。FAK蛋白和mRNA随时间的延长表达逐渐增多,48 h达到高峰。p-FAK（Tyr397）蛋白表达趋势与FAK相同。脂质体转染siRNA后FAK的mRNA和蛋白分别下调了50%和41%,下调表达FAK后可以显著抑制TGF-β1诱导的HK-2细胞α-SMA蛋白的上调表达,逆转 E-cadherin蛋白的下调表达。 结论 在TGF-β1诱导的HK-2细胞转分化进程FAK蛋白表达上调,敲低FAK蛋白表达后可以部分减轻EMT的程度,提示FAK在TGF-β1诱导的肾小管上皮细胞转分化和肾脏纤维化中发挥一定的作用。     

两种不同病理类型肾病患者尿蛋白诱导肾小管上皮细胞上调表达趋化因子及其分子信号机制研究

目的 观察不同病理类型肾病患者尿蛋白对人近端肾小管上皮细胞（HK-2）分泌趋化因子的影响并探讨其分子信号机制。 方法 所有患者均经临床和肾穿刺活检确诊为原发性局灶节段性肾小球硬化（FSGS）或微小病变性肾病（MCD）。以超滤法浓缩提取患者尿中总蛋白，分别刺激体外培养的HK-2细胞。RT-PCR检测调节正常T细胞表达和分泌的细胞因子（RANTES）及巨噬细胞移动抑制因子（MIF）的mRNA水平。免疫荧光、ELISA及流式细胞仪检测蛋白水平的表达。Western 印迹法检测p38 MAPK和胞外信号调节激酶（ERK）水平。特异性抑制剂SB203580抑制p38磷酸化；PD98059则用于抑制ERK磷酸化。 结果 两种尿蛋白成分有差异，FSGS患者尿蛋白中含有更多的大分子量蛋白。两种尿蛋白均刺激HK-2细胞RANTES及MIF表达上调，而FSGS患者尿蛋白刺激作用更强。两种尿蛋白均显著激活HK-2细胞内ERK和p38 MAPK信号通路。特异性抑制剂分别抑制ERK或p38 MAPK的活化后，FSGS患者尿蛋白介导的RANTES和MIF的上调表达作用可被SB203580或PD98059抑制，而MCD患者尿蛋白的刺激作用却仅能被SB203580所阻断。 结论 FSGS肾病患者的尿蛋白比MCD患者的尿蛋白有更强的上调HK-2细胞RANTES及MIF表达的作用。两种尿蛋白介导趋化因子上调表达的分子信号机制存在差异。     

非经典型蛋白激酶C在尿蛋白诱导肾小管上皮细胞转分化中的作用

目的:探讨非经典型PKC同工酶(PKC-ζ和PKC-ι)在尿蛋白诱导的肾小管上皮细胞(RTECs)转分化中的作用。方法:首先免疫组化法检测PKC-ζ和PKC-ι在人正常及不同类型肾小球疾病患者肾组织的表达并分析其表达量的变化。接着应用不同浓度的尿蛋白(0 mg/ml、0.5 mg/ml、1.0 mg/ml、2.0 mg/ml、4.0 mg/ml及8.0 mg/ml)处理体外培养的HK-2细胞,应用免疫细胞化学法检测HK-2细胞E-cadherin和α-SMA的表达以观察HK-2细胞转分化情况,选择诱导HK-2细胞转分化适宜的尿蛋白浓度进行后续试验。将HK-2细胞分对照组和尿蛋白组,分别给予无血清培养基和尿蛋白(4.0 mg/ml)刺激,分别用免疫荧光及Western Blot法检测各组细胞内PKC-ζ和PKC-ι在细胞膜及细胞浆的活化易位情况。结果:(1)两种非经典型PKC同工酶PKC-ζ和PKC-ι在正常和肾小球疾病肾组织肾小球和RTECs均有表达,在肾间质均无表达,表达量不尽相同。PKC-ζ在肾小球疾病肾组织肾小球中的表达量均较正常肾组织显著减少(P<0.05),在MCD和FSGS的RTECs中的表达量较正常肾组织显著减少(P<0.05)。PKC-ι在FSGS的肾小球和RTECs中的表达量均显著减少(P<0.05),在Ig AN肾组织RTECs中表达显著增高(P<0.05),在肾小球表达无明显差别。(2)不同浓度的尿蛋白刺激HK-2细胞48 h后,当尿蛋白的浓度逐渐升高时,HK-2细胞随之转变为类似成纤维细胞形态,细胞E-cadherin表达下调及α-SMA表达上调。尿蛋白浓度为4.0 mg/ml诱导HK-2细胞转分化最明显。(3)尿蛋白诱导HK-2细胞转分化时,PKC-ζ和PKC-ι无明显活化易位。结论:两种非经典型PKC同工酶均在人类肾组织表达,提示PKC-ζ和PKC-ι均参与肾脏的生理过程,但PKC-ζ和PKC-ι在尿蛋白诱导的肾小管上皮细胞转分化中并未发挥相关作用。     

JAK2／STAT3信号通路在IL-6介导肾小管上皮细胞转分化中的作用

目的：研究Janus激酶（JAK2）和信号转导因子和转录活化因子（STAT3）途径的激活在IL-6介导人近端肾小管上皮细胞转分化中的作用。方法：（1）细胞培养及分组：待生长状况良好的HK-2细胞株60%-80%细胞贴壁后,无血清培养基同步24 h,然后根据分组给予相应的刺激。（2）指标检测：采用荧光定量PCR技术检测0 h、24 h、48 h7、2 h不同时间点α-SMA mRNA、E-cadherin mRNA的表达。采用Western blot方法检测25 ng/ml浓度的IL-6刺激24 h、48 h、72 h后α-SMA、E-cadherin蛋白的表达;检测0、5、10、25、50 ng/ml浓度的IL-6刺激30 min,以及IL-6（25 ng/ml）刺激0、15 min、30 min、60 min、120 min后P-STAT3蛋白的表达水平;检测AG490预处理细胞4 h,IL-6（25 ng/ml）分别刺激30 min后及48 h后P-STAT3、P-JAK2和α-SMA、E-cadherin蛋白的表达水平。结果：与刺激前比较,IL-6以时间依赖方式上调HK-2细胞α-SMA mRNA、蛋白的表达,下调E-cadherin mRNA、蛋白的表达;IL-6以时间和剂量依赖方式上调HK-2细胞P-STAT3的表达,高峰发生在30 min;AG490部分抑制STAT3、JAK2的磷酸化,部分抑制IL-6诱导的α-SMA蛋白表达的上调、部分抑制IL-6诱导的E-cadherin蛋白表达的下调。结论：HK-2细胞中,JAK2/STAT3信号通路的激活可能参与了IL-6介导的肾小管上皮细胞转分化的发生。     

MG-132对TGF-β1诱导的人肾小管上皮细胞转分化与凋亡的影响

目的：探讨蛋白酶体抑制剂MG-132对体外培养的人近端肾小管上皮细胞（HK-2）转分化和凋亡的影响及其机制。方法：体外培养HK-2细胞,随机分组：对照组,TGF-β1刺激组（5ug／L）,MG-132组（2．5μmol／L）,MG-132＋TGF-融组（MG-132 2.5μmol／L孵育30min后再加TGF-β1 5μg／L）。培养24h后收集细胞,RT-PCR法检测Smurf1、Smurf2和Smad7 mRNA的表达;Western免疫印迹检测Smurf1、Smurf2、Smad7和P-IκB-α和IκB-α蛋白表达;免疫组织化学检测胞浆中Fn和α-SMA的表达;Hoechst 33258染色免疫荧光检测细胞凋亡形态变化,流式细胞术检测细胞凋亡率。结果：TGF-β1刺激组HK-2 Smurf1、Smurf2 mRNA及蛋白表达水平较对照组高（P〈0．05）,但Smad7 mRNA及蛋白表达水平较对照组低（P〈0．05）,且胞浆中FN和α-SMA水平较对照组高（P〈0．05）。MG-132＋TGF-β1组与TGF-β1刺激组比较,Smurf1、Smurf2 mRNA表达降低（P〈0．05）,Smad7 mRNA略升高（P〉0．05）,而Srnad7蛋白明显升高（P〈0．05）,胞浆中Fn和α-SMA表达减少。MG-132组、MG-132＋TGF-β1组分别与对照组及TGF-β1组比较,P-IκB-α和IκB-α蛋白浓度升高,细胞凋亡率增加,差异有统计学意义（P〈0．05）。结论：MG-132可抑制TGF-132诱导的HK-2 Smurf1、Smurf2的表达,促进Smad7表达,抑制其降解,减轻FN和α-SMA的表达,从而抑制HK-2转分化;另-方面,MG132可能通过抑制TGF-β1诱导的HK-2细胞NF-κB活化促进HK-2细胞凋亡。     

终末期糖基化终产物通过转化生长因子依赖和非依赖途径介导NRK52E细胞转分化和胶原Ⅰ的合成

目的探讨终末期糖基化终产物（AGEs）介导肾小管上皮细胞转分化和胶原（Col）Ⅰ合成的分子机制。方法体外培养正常大鼠近端肾小管上皮细胞系（NRK52E），应用自制的AGE-牛血清白蛋白（BSA）刺激NRK52E细胞。免疫细胞化学方法检测不同时间磷酸化（P）Smad2／3核转位情况。ELISA方法检测细胞培养上清TGF-β1的水平。RT-PCR方法检测α-平滑肌肌动蛋白（SMA）、E-钙黏着糖蛋白（cadherin）和ColⅠmRNA表达。Western印迹检测α-SMA、E-cadherin和ColⅠ蛋白的表达。同时观察TGF-β1中和抗体对AGE-BSA上述效应的阻断作用。结果基础状态下，NRK52E细胞存在低水平p-Smad2／3核表达（16％）。与BSA对照组比较，AGE—BSA以时间依赖方式上调NRK52E细胞p-Smad2／3核转位，其高峰出现在30min（68％比30.5％，P〈0．01）和24h（76％比31．3％，P〈0．01）。AGE—BSA显著上调α-SMA和ColⅠmRNA和蛋白表达；下调E-cadherin mRNA和蛋白的表达；并能促进NRK52E细胞合成和分泌TGF-β1。TGF-β1中和抗体能明显抑制AGE—BSA介导的24hp-Smad2／3核转位（25．2％，P〈0．01），但不能阻抑30min活化高峰；能明显抑制AGE-BSA介导的α-SMA和ColⅠmRNA和蛋白表达．以及显著地上调E-cadherin mRNA和蛋白的表达。结论AGEs通过TGF-β依赖和非依赖途径诱导肾小管上皮细胞Smads信号通路活化，促进其向肌成纤维母细胞转分化和ColⅠ的合成。     

Urinary proteins from patients with nephrotic syndrome alters the signalling proteins regulating epithelial–mesenchymal transition

Aim:   Proteinuria plays an important role in the progression of tubulointerstitial fibrosis, but the mechanism for the differential renal damage induced by proteinuria is unknown. This study examined the effects of urinary proteins from patients with idiopathic minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) on several epithelial–mesenchymal transition (EMT)-related marker proteins in cultured proximal tubular HK-2 cells.
Methods:   Urinary proteins from MCD and FSGS patients were extracted by ultrafiltration and incubated with HK-2 cells; the expression of the cytokeratin-18, α-smooth muscle actin (α-SMA) and vimentin were assessed. p38 and extracellular regulated kinase (ERK) activation were measured by western blotting, and SB203580 (a p38 inhibitor) and PD98059 (an ERK1/2 inhibitor) were used to inhibit their activation.
Results:   It was observed that urinary proteins from FSGS patients more significantly induced the expression of α-SMA and vimentin and reduced cytokeratin-18 expression than those from MCD patients in HK-2 cells. Both ERK1/2 and p38 were activated by urinary proteins from MCD or FSGS patients. Pretreatment of the cells with SB203580 or PD98059 abolished the effect of urinary proteins from FSGS patients on the expression of α-SMA, vimentin and cytokeratin-18, while only SB203580 elicited this effect when cells were treated with urinary proteins from MCD patients.
Conclusion:   The urinary proteins from MCD and FSGS patients induced significant changes of EMT-related proteins through activation of distinct mitogen-activated protein kinase-related signalling pathways. Quality of proteinuria may play an important role in determining the severity and progression of tubular injury associated with different kidney diseases.     

肾病综合征患者尿白蛋白诱导HK-2细胞上调内皮素1的表达

目的 探讨肾病综合征(NS)患者尿白蛋白对人近端肾小管上皮细胞(HK-2)合成内皮素1(ET-1)的调节作用。 方法 从NS患者尿中提取纯化白蛋白， 分析鉴定并用以刺激HK-2细胞。 通过逆转录多聚酶链反应(RT-PCR)法和间接免疫荧光法观察不同时间及不同浓度的白蛋白对HK-2细胞表达ET-1 mRNA及蛋白质的影响，并以正常人血清白蛋白(HSA)作对照。 结果 尿白蛋白及HSA均能上调HK-2细胞ET-1 mRNA及蛋白质表达，随着刺激时间延长表达逐渐增强，到达峰值后又逐渐下降至基线水平。随着尿白蛋白及HSA浓度的增加，HK-2细胞表达ET-1 mRNA也不断增强。 血清白蛋白需达2.5 mg/ml才具有显著上调HK-2细胞ET-1 mRNA表达效应，而0.5 mg/ml尿白蛋白即可明显上调(P < 0.05)。结论 NS患者尿白蛋白与正常人血清白蛋白均可上调HK-2细胞表达ET-1，而NS患者尿白蛋白的作用强于正常人血清白蛋白。     

狼疮肾炎患者尿蛋白通过p38丝裂素活化蛋白激酶信号途径刺激近端肾小管上皮细胞上调表达骨调素

目的探讨p38丝裂素活化蛋白激酶(MAPK)信号通路在狼疮肾炎(LN)尿蛋白介导近端肾小管上皮细胞(HK-2)表达骨调素(DPN)中的作用。方法收集狼疮肾炎患者24h的尿液提纯总蛋白，体外刺激HK-2细胞，分别用逆转录-聚合酶链式反应(RT-PCR)和Western印迹法观察应用p38MAPK特异性阻断剂SB203580对。HK-2细胞表达OPN mRNA及蛋白的影响：免疫荧光法检测OPN及其受体CD44在细胞中的表达。结果狼疮肾炎患者尿蛋白可刺激HK-2细胞OPN mRNA及蛋白上调表达，并呈时间和浓度依赖性，而SB203580可明显抑制这一作用。结论狼疮肾炎尿蛋白可通过p38MAPK途径刺激HK-2细胞OPN mRNA和蛋白上调表达。     

Podocalyxin-positive glomerular epithelial cells in urine correlate with a positive outcome in FSGS

Background: Parietal epithelial cells (PECs) and podocytes are the 2 epithelial cell types in the glomerulus. In contrast to podocytes, PECs have the ability to proliferate lifelong, and they can transdifferentiate into other cell types. We previously published that excretion of podocalyxin (PDX)-positive PECs in the urine correlates with disease activity in different glomerular diseases. Methods: In this analysis we investigated whether excretion of PDX-positive cells in the urine might have a prognostic value for proteinuria development and kidney function in focal segmental glomerulosclerosis (FSGS). Results: We found that patients diagnosed with FSGS and with significant excretion of PDX-positive cells in the urine had a negative change in serum creatinine in the follow-up analysis. In contrast to that, FSGS-patients without excretion of PDX-positive cells showed a positive change in serum creatinine. There was a significant negative correlation between PDX-positive cells in the urine and change in serum creatinine. Mean change in urine protein in FSGS patients with excretion of PDX-positive cells in the urine did not differ significantly from patients with no cell excretion, but we could demonstrate a negative correlation between PDX-positive cells and change in total urine protein. Conclusions: Our data suggest that FSGS patients excreting large amounts of PDX-positive cells in their urine have a better outcome regarding kidney function and proteinuria compared with patients without excretion of PDX-positive cells. These data imply that PDX-positive cells have a positive effect on podocyte regeneration in FSGS patients.     

表面活性蛋白A在脂多糖诱导的人肾小管上皮细胞中的表达

目的 研究表面活性蛋白A（SP-A）及其亚型在人肾组织和人肾小管上皮细胞（HK-2）的表达和分布,同时分析脂多糖（LPS）对HK-2细胞中SP-A亚型的 mRNA和蛋白表达的影响。 方法 收集10例人的肾组织,以5例人的肺组织作为对照,同时培养HK-2细胞。免疫组化法检测SP-A在人肾组织的表达部位;RT-PCR法检测SP-A mRNA在人肾组织和HK-2细胞中的表达;限制性内切酶片段长度多态性（RFLP）和测序的方法分析SP-A亚型在HK-2细胞的表达;实时定量PCR法比较SP-A mRNA在人肾组织和在人肺组织中的相对含量;Western印迹法检测人肾组织和HK-2细胞中SP-A蛋白的表达;Western印迹和ELISA法检测人的尿液和HK-2细胞培养上清液中SP-A的分泌量。RT-PCR和Western印迹检测LPS在不同浓度（0、0.1、1、2、5、10 mg/L）作用8 h及5 mg/L LPS在不同时间（0、2、4、8、16、24 h）作用HK-2细胞后,SP-A mRNA和蛋白表达的变化情况。 结果 免疫组化结果显示SP-A主要表达在肾皮质的远曲和近曲小管的肾小管上皮细胞。RFLP和测序的方法均证实HK-2细胞可同时表达SP-A1和SP-A2亚型。实时定量PCR证实SP-A mRNA在人肾组织的表达量仅为肺组织的30%（n = 5）。Western印迹检测到人肾组织和HK-2细胞可表达SP-A蛋白。同时在人的尿液和HK-2细胞培养上清液中也检测到SP-A的分泌,其分泌量分别为（106.614±72.772） nmol/L（n = 30）和（85.533± 58.622） nmol/L（n = 10）。应用1、2、5、10 mg/L的 LPS刺激HK-2细胞8 h后,SP-A1和SP-A2 mRNA及SP-A蛋白表达较0、0.1 mg/L显著升高（P < 0.05）;同时,应用5 mg/L的LPS作用HK-2细胞4、8、16、24 h后, SP-A1和SP-A2 mRNA及SP-A蛋白表达较LPS作用0、2 h显著升高（P < 0.05）。 结论 HK-2细胞能同时表达SP-A1和SP-A2亚型,能产生和分泌SP-A蛋白。SP-A1和SP-A2可能在肾脏的天然免疫和炎性反应调节方面起重要作用。     

两种病理类型肾病患者尿IgG对人肾小管上皮细胞表达巨噬细胞移动抑制因子的影响

目的 分离纯化表现为肾病综合征(NS)的微小病变型(MCD)及膜性肾病(MN)患者尿IgG，比较它们对人近端小管上皮细胞(HK-2)表达巨噬细胞移动抑制因子(MIF)的影响。方法 采用硫酸铵沉淀&#65380;蛋白G亲和层析纯化尿中IgG，并经SDS-PAGE、Western印迹分析鉴定&#65377;用不同浓度(0&#65380;0.5&#65380;1.0&#65380;2.5&#65380;5.0&#65380;10.0 mg/ml)的上述两种患者的尿IgG分别刺激HK-2细胞6 h，应用RT-PCR检测细胞表达MIF mRNA的变化;应用Western印迹检测细胞中MIF的蛋白水平&#65377; 结果 纯化的尿IgG经SDS-PAGE分析显示其分解为4个片段,以兔抗人IgG抗体进行免疫印迹鉴定，证实这些蛋白条带均为IgG成分&#65377; 两种不同病理类型NS患者的尿IgG均可上调HK-2细胞MIF 的基因及蛋白表达，并呈剂量依赖性&#65377;MN患者的尿IgG 0.1 mg/ml即可明显上调HK-2细胞MIF mRNA和蛋白表达(P < 0.01);而MCD患者的尿IgG需达到2.5 mg/ml才具有显著上调效应&#65377; 结论 呈NS的MCD和MN患者尿IgG可上调HK-2细胞表达MIF&#65377;MN患者尿IgG的作用强于MCD患者,提示这两种不同病理类型患者尿IgG可能存在结构或功能上的差异&#65377;     

Role of C3a and C5a in focal segmental glomerulosclerosis

Objective To study the role of C3a and C5a in focal segmental glomerulosclerosis (FSGS) patients. Methods (1) A total of 66 patients with FSGS confirmed by renal biopsy were selected, including 18 cases of tip lesion, 11 cases of perihilar, 22 cases of not otherwise specified (NOS), 10 cases of cellular, and 5 cases of collapsing FSGS. The normal renal tissue resected from patients with kidney tumor was taken as a negative control. The expression of C3a and C5a in renal tissues was detected by immunohistochemistry. (2) Serum and urine samples from these 66 FSGS patients were collected, and serum and urine samples from 10 healthy adult selected from the same physical examination center in the same term were used as normal controls. The levels of C3a and C5a in serum and urine were detected by enzyme-linked immunosorbent assay (ELISA). Results (1) Immunohistochemical results showed that C3a and C5a were deposited in glomerulus of FSGS patients, and no deposition in normal renal tissues. The semi-quantitative score showed that kidney C3a score was significantly correlated with serum creatinine (r=0.547, P＜0.001) and 24 h urine protein (r=0.329, P=0.007) in FSGS patients, and kidney C5a score was also significantly correlated with serum creatinine (r=0.415, P＜0.001) and 24 h urine protein (r=0.414, P＜0.001) in FSGS patients. (2) The levels of serum C3a and C5a in FSGS patients were higher than those in healthy adults (both P＜0.05), but there was no significant difference among the five pathological types (P＞0.05). The levels of urinary C3a/urinary creatinine, urinary C5a/urinary creatinine were higher in FSGS patients than those in healthy adults (all P＜0.05). The levels of urine C3a/urinary creatinine and urinary C5a/urinary creatinine in collapsing FSGS were higher than other FSGS types (all P＜0.01), but there was no significant difference among the tip lesion, the perihilar, the not otherwise specified and the cellular (P＞0.05). (3) Urinary C3a/urinary creatinine levels were significantly correlated with serum creatinine (r=0.774, P＜0.001) and 24 h urine protein (r=0.430, P＜0.001) in FSGS patients, and urinary C5a/urinary creatinine levels were also significantly correlated with serum creatinine (r=0.677, P＜0.001) and 24 h urine protein (r=0.333, P=0.007) in FSGS patients. Conclusion Complement C3a and C5a may be involved in the pathogenesis of FSGS and may be related to the severity of FSGS.     

Urinary podocytes in primary focal segmental glomerulosclerosis

BACKGROUND/AIM: Focal segmental glomerulosclerosis (FSGS) is a common cause of nephrotic syndrome. Although the pathogenesis is not known, recent studies suggest that FSGS may be a podocyte disease. The aim of this study was to look for podocyte injury in this disease, using measurements of urinary podocytes. METHODS: We examined the first morning urine of the day collected from 71 patients (45 men and 26 women, median age and range 11.2 and 3-29 years) diagnosed as having nephrotic syndrome. Freshly voided urine samples were examined by immunofluorescence labeling using monoclonal antibodies against human podocalyxin. Renal histological examinations were performed in 58 of the 71 patients: 28 had minimal-change disease, 20 had FSGS, and 10 had membranous nephropathy. RESULTS: Median and range of urinary podocytes measured were 0.2 and 0-40.8 cells/ml for 71 patients with nephrotic syndrome and 0 and 0-0.8 cells/ml for normal healthy control subjects (n = 200). Patients with FSGS had significantly higher levels of urinary podocytes (median and range 1.3 and 0-40.8 cells/ml) than those with minimal-change disease (median and range 0 and 0-6.9 cells/m; p = 0.003) or membranous nephropathy (median and range 0 and 0-1.4 cells/ml; p = 0.02). CONCLUSIONS: The urinary excretion of podocytes is significantly higher in patients with FSGS as compared with those having membranous nephropathy or minimal-change disease. These findings suggest that podocyte injury and loss in the urine may have an important role in the pathogenesis of FSGS.     

The effect of pH and nucleophiles on complement activation by human proximal tubular epithelial cells.

BACKGROUND: Activation of urinary complement proteins in situ by proximal tubular epithelial cells (PTEC) may contribute to the mediation of tubulointerstitial injury in patients with significant proteinuria. However, the mechanism involved is unclear, and the role of changes in urinary pH and in the concentrations of urea or ammonia requires further clarification. METHODS: The protein fraction of urine samples from nine patients with proteinuria >1.5 g/day was purified. A cell ELISA involving cultured HK-2 PTEC was used to investigate the capacity of urinary protein to promote the deposition of both C3 and C9 on the cell surface. The effect of variations in pH (5.5-8.0) and in the concentration of urea and ammonia was also examined. C3 was purified and used to further investigate the mechanism of complement deposition. RESULTS: Urine samples from the majority of patients induced deposition of C3 and C9 on the surface of HK-2 cells via the alternative pathway. This process was maximal at acidic pH values. Preincubation of urinary complement or serum with urea or ammonia inhibited C3 deposition. Purified C3 incubated with HK-2 cells showed no evidence of activation in the absence of other complement components. CONCLUSIONS: These data suggest that bicarbonate protects against complement-mediated damage in the lumen by increasing the local pH, rather than by inhibiting the generation of ammonia. PTEC appear to activate complement through provision of a 'protected site' on their surface, rather than by the activation of C3 by convertase-like protease(s).