Netrin-1对高糖诱导的肾小管上皮细胞损伤的影响

目的:研究netrin-1对高糖诱导的肾小管上皮细胞损伤的影响。方法:用高糖培养人肾小管上皮HK-2细胞,real-time PCR和Western blot测定细胞中netrin-1的表达水平。用过表达netrin-1慢病毒感染HK-2细胞,检测其对高糖环境下HK-2细胞中netrin-1表达的影响。流式细胞术测定细胞凋亡,Western blot测定cleavedcaspase-3蛋白水平,2,4-二硝基苯肼法检测培养液中乳酸脱氢酶(LDH)活性,硫代巴比妥酸法检测培养液中丙二醛(MDA)含量,ELISA法测定培养液中白细胞介素1β(IL-1β)和肿瘤坏死因子α(TNF-α)含量。结果:高糖处理后的HK-2细胞中netrin-1的mRNA和蛋白水平均明显下调(P 0.05)。过表达netrin-1慢病毒能够上调高糖环境下HK-2细胞中netrin-1的表达水平(P 0.05)。高糖可促进肾小管上皮细胞分泌IL-1β和TNF-α,提高细胞培养液中LDH和MDA的水平(P 0.05),使肾小管上皮细胞的caspase-3活化并诱导细胞凋亡;上调netrin-1的HK-2细胞经高糖诱导后,细胞分泌的IL-1β和TNF-α减少,细胞中活化的caspase-3蛋白水平降低,培养液中LDH和MDA水平降低,细胞凋亡减少(P 0.05)。结论:上调netrin-1减轻高糖诱导的肾小管上皮细胞氧化损伤和炎性损伤,减少细胞凋亡。     

C-反应蛋白诱导人肾小管上皮细胞凋亡

目的:探讨与微炎症状态相应的C-反应蛋白(CRP)水平是否诱导肾小管上皮细胞凋亡。方法:以微炎症状态相应的CRP浓度刺激HK-2细胞。采用AnnexinⅤ-FITC、PI染色和流式细胞术检测凋亡细胞的百分率。采用Hoechst 33258染色观察肾小管上皮细胞凋亡的形态学改变。比色法检测细胞caspase-3活性。Real-time PCR检测促凋亡基因bax、抗凋亡基因bcl-2的mRNA表达。结果:CRP呈剂量和时间依赖性地诱导HK-2细胞凋亡,细胞凋亡在CRP浓度为10 mg/L时达高峰,在20 mg/L时则以晚期凋亡和坏死为主。Hoechst 33258细胞核染色显示CRP作用的HK-2细胞呈现染色质浓缩、碎裂或染色质边集等细胞凋亡的特点。CRP增高细胞caspase-3的酶活性、上调促凋亡基因bax的表达和下调抗凋亡基因bcl-2的表达。结论:CRP轻度增高可诱导肾小管上皮细胞凋亡。     

干扰维生素D3上调蛋白1通过调控Shh影响高糖诱导的肾小管上皮细胞凋亡

目的:探讨维生素D3上调蛋白1(VDUP-1)对高糖诱导的肾小管上皮细胞凋亡的影响及机制。方法:人近端肾小管上皮HK-2细胞用高糖处理后,real-time PCR和Western blot检测细胞中VDUP-1的水平。HK-2细胞转染VDUP-1小干扰RNA,real-time PCR和Western blot检测抑制效果。高糖条件培养VDUP-1表达下调的HK-2细胞,流式细胞术检测细胞凋亡,试剂盒检测细胞中caspase-3和caspase-9的活性,ELISA法测定培养上清液中肿瘤坏死因子α(TNF-α)含量,Western blot检测细胞中音猬因子(Shh)信号通路关键蛋白Patched 1 (Ptch1)、Smoothened (Smo)、锌指蛋白Gli2和Shh的水平。用外源性Shh处理HK-2细胞,Western blot检测Ptch1、Smo和Gli2的水平。用外源性Shh处理VDUP-1表达下调的HK-2细胞,高糖处理后,流式细胞术检测细胞凋亡,试剂盒检测细胞中caspase-3和caspase-9的活性,ELISA法测定培养液上清中TNF-α含量。结果:高糖处理后,HK-2细胞中VDUP-1的mRNA和蛋白水平升高(P 0. 05)。转染VDUP-1小干扰RNA后,HK-2细胞中VDUP-1的mRNA和蛋白水平下降(P 0. 05)。与正常培养的细胞相比,高糖处理后HK-2细胞凋亡率显著升高,细胞中caspase-3和caspase-9活性明显升高,TNF-α含量亦明显升高(P 0. 05);下调VDUP-1表达后的HK-2细胞经高糖处理后细胞凋亡率显著降低,细胞中caspase-3和caspase-9活性也明显降低(P 0. 05)。高糖培养后细胞中Ptch1、Smo、Gli2和Shh的蛋白水平下降,而下调VDUP-1表达部分拮抗高糖对HK-2细胞中Ptch1、Smo、Gli2和Shh表达的影响。外源性Shh可以促进细胞中Ptch1、Smo和Gli2的表达,抑制高糖诱导的HK-2细胞凋亡和分泌TNF-α,与下调VDUP-1共同抑制高糖诱导的肾小管上皮细胞凋亡。结论:干扰VDUP-1表达可能通过激活Shh信号通路抑制高糖诱导的肾小管上皮细胞凋亡和分泌TNF-α。     

氧化应激和P53参与波动高糖诱导的肾小管上皮细胞凋亡

目的: 探讨波动性高糖引起的肾小管上皮细胞凋亡的机制。方法: 体外培养人肾小管上皮细胞 (HK-2),给予稳定高糖或波动高糖干预,并使用抗氧化剂和P53特异性抑制剂验证氧化应激和P53在波动高糖诱导的肾小管上皮细胞凋亡中的作用;此外,SD大鼠随机分为正常对照组(A)、糖尿病稳定高血糖组(B)和糖尿病波动高血糖组(C)。采用链脲佐菌素(STZ)65 mg/kg腹腔注射诱发糖尿病,血糖波动组每天定时腹腔注射速效胰岛素,并错时给予葡萄糖,造成一天中血糖浓度大幅波动模型。采用比色法检测超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量,免疫组化法和Western blotting检测NADPH氧化酶4(Nox4)和P53蛋白表达,流式细胞术和原位缺口末端标记法(TUNEL)检测肾脏细胞凋亡。结果: (1)与稳定高糖比较,波动高糖引起更加明显的HK-2细胞凋亡,P53蛋白表达明显上调,同时培养上清液中MDA含量增加和SOD活性下降,抗氧化剂和P53抑制剂可明显抑制磷酸化P53蛋白表达和细胞凋亡。(2)在体动物实验制模12周后,与B组比较,C组肾组织Nox4表达明显增加,肾小管磷酸化P53蛋白表达上调,细胞凋亡数增加。结论: 氧化应激和P53参与波动性高糖诱导的肾小管上皮细胞凋亡。     

肾损伤分子-1参与碘对比剂致人肾小管上皮细胞体系HK-2凋亡

目的探讨肾损伤分子-1(KIM-1)在对比剂所致肾小管上皮细胞凋亡中的作用及其可能机制。方法培养人肾小管上皮细胞系HK-2,给予75 mg/mL的碘海醇(对比剂)处理不同时间,用Western blot检测KIM-1蛋白表达。设计siRNA靶向干扰KIM-1基因表达,将细胞分为对照组(A)、对比剂组(B)、对比剂+空载组(C)、对比剂+KIM-1-siRNA组(D);除对照组,每组给予75 mg/mL碘海醇处理2 h,通过流式细胞计量术以及检测Bax和Bcl-2的表达评估细胞凋亡;观察各组丙二醛(MDA)、活性氧(ROS)、超氧化物歧化酶(SOD)和单核细胞趋化蛋白1(MCP-1)水平;评估KIM-1在对比剂导致HK-2细胞损伤中的可能机制。结果 75 mg/mL碘海醇处理HK-2细胞后,KIM-1表达增多,2 h时最明显。当给予碘海醇处理HK-2细胞2 h后,细胞发生明显凋亡,同时ROS和MCP-1水平上升(P0.05),而SOD和MDA水平下降(P0.05);转染siRNA靶向干扰KIM-1基因表达后,相比较对比剂组,细胞凋亡程度明显减轻,同时伴随ROS和MCP-1水平下降,SOD和MDA水平上升(P0.05)。结论碘对比剂可导致HK-2细胞的KIM-1表达增加,而KIM-1可能通过促进氧化应激及炎性反应参与碘对比剂所致HK-2细胞凋亡。     

JAK/STAT信号途径参与高糖诱导的肾小管上皮细胞转分化

目的：观察Janus激酶/信号转导和转录活化因子(JAK/STAT) 信号的激活对高糖诱导肾小管上皮细胞转分化的影响。方法:体外培养人肾近曲小管上皮细胞株（HKCs）,分别给予高糖和JAK拮抗剂AG490干预,采用免疫沉淀和Western印迹检测JAK2的磷酸化;Western印迹检测平滑肌肌动蛋白(α-SMA)、E-钙黏素(E-cadherin)及信号蛋白STAT1、STAT3、磷酸化STAT1 (phospho-STAT1, p-STAT1) 和p-STAT3的水平; 酶联免疫吸附法(ELISA)测定细胞上清液中转化生长因子β₁(TGF-β₁)和I型胶原的分泌,逆转录聚合酶链反应(RT-PCR)检测TGF-β₁mRNA表达。结果:与低糖对照组比较,高糖培养的HKCs中α-SMA 的水平及p-JAK2 、p-STAT1 和p-STAT3 比例明显上调；E-cadherin表达明显下调；TGF-β₁ mRNA 表达增加；细胞培养上清液中TGF-β₁、Ⅰ型胶原分泌增加。AG490明显抑制JAK2磷酸化、下调p－STAT1 和p-STAT3的同时,明显抑制高糖刺激HKCs中α-SMA表达的升高，减轻E-cadherin表达下降程度；降低TGF-β₁ mRNA 表达及TGF-β₁、Ⅰ型胶原的分泌。结论:JAK/STAT信号途径参与高糖诱导的HKCs转分化，并刺激TGF-β₁和细胞外基质的分泌。     

淫羊藿苷通过抑制PI3K/AKT信号通路抑制高糖诱导的人肾小管上皮细胞上皮-间充质转化

目的：探讨淫羊藿苷（ICA）对高糖（HG）诱导的人肾小管上皮细胞上皮-间充质转化（EMT）的影响及机制。方法：将人肾小管上皮HK-2细胞分为正常对照（NC）组（5.5 mmol/L D-葡萄糖）、高渗（OSM）组（5.5mmol/L D-葡萄糖+24.5 mmol/L甘露醇）、HG组（30 mmol/L D-葡萄糖）、低剂量ICA(L-ICA)组（30 mmol/L D-葡萄糖+10μmol/L ICA）、高剂量ICA(H-ICA)组（30 mmol/L D-葡萄糖+40μmol/L ICA）、H-ICA+SC79[蛋白激酶B(PKB/AKT)激活剂]组（30 mmol/L D-葡萄糖+40μmol/L ICA+10μmol/L SC79）和LY294002[磷脂酰肌醇3-激酶（PI3K）抑制剂]组（30 mmol/L D-葡萄糖+10μmol/L LY294002）。CCK-8法检测细胞活力;倒置显微镜观察细胞形态;RT-qPCR检测细胞α-平滑肌肌动蛋白（α-SMA）和上皮钙黏素（E-cadherin）的mRNA表达水平;Western blot检测细胞中α-SMA、Ecadher...     

辛伐他汀抑制高糖诱导人脐静脉内皮细胞的凋亡

背景：他汀类药物对血管内皮细胞的凋亡是否有影响目前尚不明确。 目的：探讨辛伐他汀对高糖诱导的人脐静脉内皮细胞凋亡的影响。 方法：用DMEM细胞培养液培养人脐静脉内皮细胞,将细胞分成空白对照组、高糖组和高糖+辛伐他汀组,用四甲基偶氮唑蓝比色法测定人脐静脉内皮细胞的存活率,流式细胞仪和Western blot分别检测细胞早期凋亡率及P53蛋白表达。 结果与结论：高糖组及高糖+辛伐他汀组细胞增殖率较空白对照组明显降低(P < 0.01),而高糖组细胞增殖率较高糖+辛伐他汀组亦降低(P < 0.01);高糖组P53蛋白表达量及凋亡率较空白对照组及高糖+辛伐他汀组明显增加(P < 0.01),高糖+辛伐他汀组P53蛋白表达及凋亡率亦明显高于空白对照组(P< 0.01)。表明高糖可通过促进促凋亡蛋白P53的表达进而促进人脐静脉内皮细胞的凋亡,而辛伐他汀可抑制此作用。     

circITCH靶向miR-106b-5p对高糖诱导的肾小管上皮细胞IL-6、TNF-α表达和细胞凋亡的影响

目的探讨cirITCH对高糖(HG)诱导的人肾小管上皮细胞炎症因子IL-6、TNF-α表达和凋亡的影响和可能机制。方法体外培养人肾小管上皮细胞HK-2,用25 mmol/L葡萄糖诱导24 h,RT-qPCR法检测细胞中cirITCH和miR-106b-5p表达。分别转染cirITCH过表达载体、miR-106b-5p抑制剂或共转染cirITCH过表达载体与miR-106b-5p模拟物至HK-2细胞后,用25 mmol/L葡萄糖诱导24 h,酶联免疫吸附法检测细胞培养上清中IL-6和TNF-α水平,流式细胞术检测细胞凋亡,Western blot检测细胞中Bcl-2和Bax蛋白表达。双荧光素酶报告基因实验验证cirITCH和miR-106b-5p调控关系。结果 HK-2细胞经高糖诱导后,细胞中circITCH表达降低,而miR-106b-5p表达升高。上调cirITCH或下调miR-106b-5p可减少高糖诱导的HK-2细胞分泌IL-6和TNF-α,并降低细胞凋亡率和Bax蛋白表达,而增加Bcl-2蛋白表达。circITCH靶向负调控miR-106b-5p表达,上调miR-106b-5p...     

黄芪多糖对糖尿病肾病肾小管上皮细胞凋亡、转分化及ROS 含量的影响研究

目的:探讨黄芪多糖对糖尿病肾病肾小管上皮细胞凋亡、转分化及ROS 含量的影响。方法:HK-2 细胞分为低糖组、高糖组和黄芪多糖+高糖组,处理细胞48 h 后,CCK-8 实验检测细胞增殖;流式细胞仪检测细胞凋亡及ROS 含量;Western blot 检测E-cadherin、α-SMA、STAT1、STAT3、p-STAT1、p-STAT3 蛋白表达。结果:高糖组细胞存活率显著低于低糖组(P<0.01),细胞凋亡率、ROS 含量及E-cadherin、α-SMA、p-STAT1、p-STAT3 蛋白表达均显著高于低糖组(P<0.01),高糖+黄芪多糖组细胞存活率显著高于高糖组,细胞凋亡率、ROS 含量及E-cadherin、α-SMA、p-STAT1、p-STAT3 蛋白表达均显著低于高糖组(P<0.01)。结论:黄芪多糖可促进高糖诱导的肾小管上皮细胞增殖,抑制细胞凋亡及转分化,其机制与下调JAK/ STAT 信号通路有关。     

EGFR在高糖诱导下人肾小管上皮细胞凋亡中的作用

目的观察EGFR信号通路对高糖诱导下人肾小管上皮细胞(HK-2)凋亡的影响和机制。方法体外培养HK-2细胞,将细胞分为4组:对照组、渗透压对照组、高糖组和高糖加EGFR抑制剂AG1478组。用Western blot检测p-EGFR、total EGFR、cleaved caspase-3、BAX、BCL-2及β-actin的蛋白表达,四唑盐比色法(MTT)检测细胞活性,流式细胞术检测细胞凋亡。结果与对照组和渗透压对照组相比,高糖组HK-2细胞EGFR活性、cleaved caspase-3表达、BAX/BCL-2比值和内质网应激(ERS)明显升高,细胞活性降低(P0.01)。EGFR抑制剂AG1478能够明显抑制高糖诱导的HK-2细胞EGFR活化和细胞凋亡(P0.05),提高细胞活性(P0.05),同时抑制内质网应激(P0.05)。结论抑制EGFR活性能够减少高糖诱导的HK-2细胞凋亡,这可能是通过减少内质网应激实现的。     

尿本周蛋白促进肾小管上皮细胞凋亡的体外研究

多发性骨髓瘤(MM)患者尿本周蛋白(BJP)对肾近端小管上皮细胞(PTC)具有直接毒性,本研究通过体外观察BJP对PTC的凋亡作用以探讨BJP对PTC的部分毒性机制。将自MM患者尿中提取并经免疫固定法琼脂糖凝胶电泳进行鉴定的4例κ和λ型BJP以不同浓度与大鼠NRK52E株PTC共同培养12～48h,用原位末端标记法、流式细胞仪及透射电镜检测凋亡。结果显示:①BJPκ组与BJPλ组BJP为10mg/ml与20mg/ml时诱导PTC凋亡的比例明显高于对照组及5mg/ml,两组诱导PTC凋亡的比例随着培养时间的延长而显著增加且明显高于空白对照组;②BJPκ组与BJPλ组之间诱导PTC凋亡的比例无明显差异。结果表明,κ与λ型BJP均可诱导PTC凋亡,且随着BJP浓度及培养时间增加而增强。     

中毒性急性肾衰早期肾近曲小管上皮细胞细胞骨架的改变

目的 :了解中毒性急性肾衰 (ARF)早期肾近曲小管上皮细胞 (PTC)细胞骨架微丝和微管的改变 ,并探讨其改变的机制。方法 :采用皮下注射氯化汞建立中毒性ARF模型 ,用免疫组化和电镜法观察中毒 6h和 12hPTC细胞骨架微丝和微管的改变 ,并用高效液相色谱法测试细胞内ATP水平。结果 :免疫组化显示微丝随着中毒时间的延长 ,PTC刷状缘损伤逐渐加重 ,胞浆内有片状肌动蛋白分布 ;电镜示中毒 6h微绒毛变成球形小体 ,中毒 12h微绒毛部分缺失 ;免疫组化微管示中毒 6hPTC严重受损 ,着色变浅、不规则 ,中毒 12h着色部分恢复 ;细胞内ATP水平随着中毒时间延长而逐渐下降。结论 :中毒性ARF时 ,PTC细胞骨架微丝和微管发生变化 ,微丝的改变可能与细胞内ATP水平相关。     

内质网应激诱导人乳腺癌MDA-MB-231细胞系凋亡

目的探讨内质网应激(ERS)致雌激素受体阴性(ER-)人乳腺癌MDA-MB-231细胞系凋亡及钙激活中性蛋白酶2(calpain2)在凋亡效应中的作用。方法实验设空白对照组(DMEM)、对照组(DMEM+DMSO)和实验组,用不同浓度衣霉素(TM)诱导乳腺癌细胞不同时间,MTT法和流式细胞术检测细胞增殖抑制率及凋亡率;Western blot法检测葡萄糖调节蛋白78(GRP78)表达量,以GRP78表达最高点确定ERS模型建立,检测凋亡相关蛋白caspase4和CHOP表达以及calpain及其内源性抑制酶calpastatin的表达,用ERS抑制剂(4-PBA)和calpain抑制剂(calpeptin)分别预处理细胞2 h,观察对上述效应的影响。结果 9、12和18μmol/L TM诱导ERS对该细胞增殖有明显抑制效应,抑制率分别为33.88%±1.32%、51.51%±8.85%和55.77%±2.61%,细胞凋亡率分别为9μmol/L TM组16.70%±0.46%和12μmol/L TM组28.1%±1.09%,与对照组相比有明显差异(P0.05);9μmol/L TM诱导细胞24 h的GRP78表达上调最高(P0.01);ERS还可明显上调caspase4、CHOP和calpain表达,下调calpastatin表达(P0.01或P0.05),上述效应均能被4-PBA和calpeptin减弱或阻断(P0.05)。结论 ERS可诱导MDA-MB-231细胞凋亡,calpain2参与调控凋亡发生。     

Induction of apoptosis in human renal proximal tubular epithelial cells by Escherichia coli verocytotoxin 1 in vitro

Verocytotoxin 1 and 2 (VT1 and 2) produced by verocytotoxin-producing Escherichia coli have been considered to play an important role in the pathogenesis of glomerular and tubular damage in the epidemic form of hemolytic uremic syndrome (HUS). VTs are known to be cytotoxic to culture cells by inhibiting cellular protein synthesis. In this in vitro study, the mechanism(s) of tubular damage in HUS and the ability of VT1 to induce apoptosis in normal human renal proximal tubular epithelial cells (HRPTEC) were examined. VT1 markedly reduced cell viability of HRPTEC and rapidly inhibited overall protein synthesis. VT1 directly induced apoptotic cell death in HRPTEC in a dose- and time-dependent fashion, and co-incubation with tumor necrosis factor-α enhanced the VT1-induced apoptosis. These results suggest that apoptosis induced by VT1, possibly in concert with host cytokines, in renal tubular cells may contribute to the tubular damage in HUS. Received: 15 December 1998     

促红细胞生成素对急性肾损伤大鼠肾小管细胞凋亡和p-MAPKAPK-2表达的影响

目的:探讨促红细胞生成素(EPO)对急性肾损伤大鼠肾小管细胞凋亡和MAPKAPK-2水平的影响.方法:30只SD雄性大鼠分为假手术组、模型组、EPO治疗组,假手术组仅分离肾被膜后逐层关闭腹腔;模型组采用缺血再灌注法建立急性肾损伤模型;EPO治疗组为急性肾损伤大鼠腹腔注射EPO 50 U/kg,每周3次,共6周,其余大鼠...     

Effect of isotonic volume expansion on proximal tubular reabsorption of Na and fluid in the developing rat kidney1

Young rats (aged 22–24 days) and adult rats (aged 40–42 days) were studied during hydropenia (HP) and during volume expansion (VE) in order to clarify the role of the proximal tubule of the immature kidney in the blunted natriuretic response seen in young mammals during VE. The position of the last accessible site for micropuncture of the proximal tubular segment was determined. The disadvantages of using lissamine green as a marker of different tubular segments were investigated. Tubular function was ascertained by micropuncture of superficial proximal nephrons. Measurements of tubular length were made from latex casts of the proximal tubule. No side-effects of lissamine green were detected, when small quantities were used (20–30 μl) and at least 20 min elapsed between the infusions of the dye and tubular samplings. The last accessible proximal tubule available for micropunction was found to be similarly located in young and adult rats. Fractional reabsorption during HP remained constant during development. An equivalent degree of VE induced an increase in tubular load in both age groups, but it was more marked among younger rats. Absolute proximal reabsorption in both young and old rats in HP paralleled that of the tubular load. Fractional reabsorption, however, decreased slightly during VE but to the same extent in both age groups. This indicates a great flexibility in the immature proximal tubule under various tubular loads although it had been thought that this part of the nephron was in the later stages of development. The results imply that the proximal tubule does not create the blunted sodium response in the immature kidney during VE.     

肾脏黏液性管状和梭形细胞癌临床病理学观察

目的 探讨肾脏黏液性管状和梭形细胞癌的临床病理学特征、免疫表型及鉴别诊断。方法 应用常规病理、免疫组化方法观察1例肾脏黏液性管状和梭形细胞癌并复习相关文献。结果 肿物与周围肾组织分界清楚，组织学特点是排列呈管状的上皮样细胞，片状的梭形细胞和黏液性间质，无明显核的异型性，缺乏坏死。免疫组化：CK、EMA、vimentin阳性，SMA、desmin、S-100蛋白、HMB45等阴性。结论 肾脏黏液性管状和梭形细胞癌是WHO新确定的一类罕见的低度恶性肾上皮性肿瘤，预后较好，要与后肾腺瘤、肉瘤样癌和集合管癌等疾病相鉴别。     

Mucinous tubular and spindle cell carcinoma of the kidney: cytopathologic findings

A 54-year-old woman was hospitalized for flank pain and acute renal failure when imaging studies revealed a 5.2 cm mass in the left kidney. She was referred for fine needle aspiration of the lesion, which showed an epithelial tumor with round to oval nuclei associated with strands of metachromatic stromal tissue. Cytopathologic diagnosis was consistent with renal cell carcinoma. Subsequent nephrectomy was performed and the surgical pathology specimen showed a mucinous tubular and spindle cell carcinoma of the kidney. The patient has done well post-operatively with 10 months of benign follow-up.     

Proximal tubular cells contain a phenotypically distinct,scattered cell population involved in tubular regeneration

Regeneration of injured tubular cells occurs after acute tubular necrosis primarily from intrinsic renal cells. This may occur from a pre‐existing intratubular stem/progenitor cell population or from any surviving proximal tubular cell. In this study, we characterize a CD24‐, CD133‐, and vimentin‐positive subpopulation of cells scattered throughout the proximal tubule in normal human kidney. Compared to adjacent ‘normal’ proximal tubular cells, these CD24‐positive cells contained less cytoplasm, fewer mitochondria, and no brush border. In addition, 49 marker proteins are described that are expressed within the proximal tubules in a similar scattered pattern. For eight of these markers, we confirmed co‐localization with CD24. In human biopsies of patients with acute tubular necrosis (ATN), the number of CD24‐positive tubular cells was increased. In both normal human kidneys and the ATN biopsies, around 85% of proliferating cells were CD24‐positive – indicating that this cell population participates in tubular regeneration. In healthy rat kidneys, the novel cell subpopulation was absent. However, upon unilateral ureteral obstruction (UUO), the novel cell population was detected in significant amounts in the injured kidney. In summary, in human renal biopsies, the CD24‐positive cells represent tubular cells with a deviant phenotype, characterized by a distinct morphology and marker expression. After acute tubular injury, these cells become more numerous. In healthy rat kidneys, these cells are not detectable, whereas after UUO, they appeared de novo – arguing against the notion that these cells represent a pre‐existing progenitor cell population. Our data indicate rather that these cells represent transiently dedifferentiated tubular cells involved in regeneration. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.