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。     

表面活性蛋白-A对脂多糖诱导的人肾小管近曲上皮细胞白介素-6表达的影响

目的：探讨表面活性蛋白-A（SP-A）的表达改变对脂多糖（LPS）诱导的人肾小管近曲上皮细胞（HK-2细胞）白介素-6（IL-6）表达的影响及机制。方法培养HK-2细胞,ELISA方法检测不同浓度的LPS（0、0．1、1、2、5、10 mg／L）作用8 h及5 mg／L的LPS于不同时间（0、2、4、8、16、24 h）作用HK-2细胞后IL-6蛋白表达的变化;应用脂质体转染法将SP-A SiRNA转染入HK-2细胞,筛选稳定转染细胞株,采用5 mg／L的LPS刺激SP-A SiRNA稳定转染的HK-2细胞8 h,ELISA方法检测细胞上清中IL-6的分泌量,Western印迹检测细胞NF-κB p65蛋白的表达。结果应用1、2、5、10 mg／L的LPS刺激HK-2细胞8 h后,IL-6蛋白表达水平较0、0．1 mg／L的LPS刺激后显著升高（P＜0．05）;同时,应用5 mg／L的LPS作用HK-2细胞4、8、16、24 h后,IL-6蛋白的表达水平较5 mg／L的LPS作用0、2 h显著升高（P＜0．05）。SP-A SiRNA转染的HK-2细胞经LPS刺激后,其NF-κBP65和IL-6蛋白表达较未转染经LPS刺激细胞明显升高（P＜0．05）。结论 SP-A可能通过抑制NF-κB p65的表达进而下调LPS诱导的HK-2细胞IL-6的表达,在脓毒症急性肾损伤时发挥保护作用。     

PPARγ活化对TGF-β1诱导肾小管上皮细胞趋化因子表达的干预作用

目的：观察PPARγ活化对转化生长因子-β1（TGF-β1）诱导的肾小管上皮细胞炎症相关趋化因子表达的影响,探讨其在肾脏纤维化中的干预作用。方法：体外培养肾小管上皮细胞HK-2,LDH法检测15d-PGJ2和TGL对HK-2的细胞毒性,应用不同浓度的15d-PGJ2和TGL作用于TGF-β1诱导下的HK-2细胞,应用实时荧光定量PCR技术和ELISA方法检测趋化因子单核细胞趋化蛋白-1（MCP-1）、白细胞介素-8（IL-8）表达的变化。结果：5μmol/L15d-PGJ2和2.5μmol/LTGL不影响HK-2细胞MCP-1和IL-8mRNA基础表达和蛋白分泌。TGF-β1作用24h时,2.5μmol/L和5μmol/L15d-PGJ2及2.5μmol/LTGL均能有效干预TGF-β1诱导的MCP-1mRNA表达和蛋白的分泌（P〈0.05）。IL-8的表达与MCP-1相似,2.5μmol/L和5μmol/L15d-PGJ2能显著抑制TGF-β1诱导的IL-8表达,TGF-β1诱导24h时2.5μmol/LTGL能显著抑制IL-8mRNA表达（P〈0.05）。结论：PPARγ激动剂15d-PGJ2和TGL作用均能有效干预TGF-β1诱导的肾小管上皮细胞趋化因子MCP-1和IL-8的表达,可能具有有效干预肾间质炎症作用。     

罗格列酮对脂多糖诱导肾小管上皮细胞趋化因子分泌的影响及可能机制

目的 探讨罗格列酮（RGL）对脂多糖（LPS）诱导人近端肾小管上皮细胞（HK-2）趋化因子分泌的影响及可能机制。 方法 用RGL（10 μmol/L）预处理HK-2细胞2 h后加入LPS（1 mg/L）,与单纯LPS组、单纯RGL组及未加任何刺激（CON）组进行比较。用实时定量PCR方法检测细胞中白细胞介素8（IL-8）和单核细胞趋化蛋白1（MCP-1） mRNA表达水平;用ELISA法检测细胞培养上清中IL-8和MCP-1蛋白水平。通过RNAi技术沉默肾小管上皮细胞过氧化物酶体增殖蛋白激活性受体γ（PPARγ）,观察RGL的作用是否依赖于PPARγ。用Western印迹法检测细胞核中NF-κB蛋白水平;用EMSA方法检测NF-κB DNA结合活性。 结果 在HK-2细胞中,与CON组相比,单纯LPS刺激使IL-8、MCP-1 mRNA分别升高（4.30±0.45）倍和（4.80±1.29）倍（均P < 0.05）,使培养上清中IL-8、MCP-1分别升高（1.39±0.18）和（2.11±0.47）倍（均P < 0.05）;与LPS组相比,RGL预处理组IL-8和MCP-1在mRNA水平分别下降66.37%和71.88%（均P < 0.05）,在蛋白水平分别下降41.68%和47.87%（均P < 0.05）。在PPARγ沉默的HK-2细胞中,RGL预处理2 h后再加LPS刺激,IL-8和MCP-1 mRNA仅分别下降18.16%、16.83%,培养上清中IL-8和MCP-1仅分别下降11.39%、11.86%,与单纯LPS组相比差异无统计学意义。RGL预处理2 h不能抑制LPS诱导的NF-κB核易位,但可显著降低NF-κB DNA结合活性。 结论 RGL以PPARγ依赖的方式抑制LPS诱导HK-2细胞分泌IL-8和MCP-1,其机制可能与降低NF-κB DNA结合活性有关。     

白蛋白对肾小管上皮细胞血管紧张素转换酶表达的影响

目的 观察白蛋白对肾小管上皮细胞血管紧张素转换酶（ACE） mRNA和蛋白水平表达的影响，并探讨尿蛋白激活肾脏局部肾素-血管紧张素系统（RAS）的机制。 方法 分别采用2.5、5、10 g/L的牛血清白蛋白（BSA）刺激人近端肾小管上皮细胞株（HK-2） 6 h和12 h。并分别采用实时定量PCR和Western印迹检测ACE mRNA和蛋白水平的表达。 结果 与对照组相比，随着BSA刺激浓度的增加，HK-2细胞ACE mRNA表达均显著增加（均P <0.05)。同时，Western印迹显示ACE蛋白表达也均显著增加(均P < 0.05)。另外，BSA 10 g/L作用于HK-2细胞6 h和12 h后，ACE mRNA表达显著增加(均P < 0.05)；Western印迹显示ACE蛋白也显著增加（均P < 0.05）。 结论 BSA可显著增加HK-2细胞ACE表达，此作用可能是导致肾间质局部AngⅡ蓄积从而启动肾小管间质纤维化的重要机制之一。     

Smad锚着蛋白在糖尿病肾病肾小管上皮细胞转分化中的作用及机制研究

目的 研究Smad锚着蛋白(SARA)在高葡萄糖诱导的HK-2细胞转分化中的作用及相关机制.方法 用高浓度葡萄糖(30 mmol/L D-葡萄糖)刺激HK-2细胞,分别采用细胞免疫荧光、Western印迹及实时定量PCR等方法检测HK-2细胞波形蛋白(vimentin)、紧密连接蛋白(ZO-1)、SARA、转化生长因子β1(TGF-β1)、Smad2及Smad3的表达.分别转染全长SARA质粒[SARA (WT)]及敲除SBD结构域的SARA质粒[SARA(dSBD)],检测转染后高糖诱导的HK-2细胞Vimentin、ZO-1、Smad2、Smad3、p-Smad2、p-Smad3表达的变化.结果 高糖刺激时,HK-2细胞出现转分化 ;ZO-1蛋白和mRNA表达呈时间依赖性下调 ;vimentin蛋白和mRNA表达呈时间依赖性上调,而SARA蛋白和mRNA表达呈时间依赖性下调 ;TGF-β1、Smad3蛋白和mRNA表达呈时间依赖性上调 ;Smad2 mRNA表达呈时间依赖性上调,而其蛋白表达呈时间依赖性下调 ;Smad2和Smad3磷酸化,Smad3活化时间更长.与高糖刺激组相比,转染全长SARA质粒[SARA (WT)]过表达SARA使HK-2细胞ZO-1表达上调(P＜0.05) ;vimentin表达下调(P＜0.05) ;Smad2蛋白表达上调,但mRNA表达无明显变化 ;Smad2活化时间延长.转染SARA(dSBD)质粒对高糖诱导的HK-2细胞ZO-1、vimentin、Smad2的表达无影响,对Smad2和Smad3的磷酸化亦无明显影响.结论 高糖诱导的HK-2细胞转分化过程中,TGF-β1信号通路活化,SARA的表达下调.过表达SARA可能通过上调Smad2的蛋白表达,延长Smad2活化时间,从而抑制TGF-β1信号传导,进而抑制高糖诱导的HK-2细胞转分化进程.     

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。     

大黄酸对转化生长因子β1诱导的人肾小管上皮细胞血小板反应蛋白1表达的影响

目的探讨大黄酸对转化生长因子β1（transforming growth factor β1,TGF-β1）诱导的人肾小管上皮细胞（HK-2）血小板反应蛋白1（thrombospondin-1,TSP1）表达的影响。方法体外培养细胞,观察TGF-β1（4ng／ml）诱导下低、中、高浓度的大黄酸（10μg／ml、20μg／ml和40μg／ml）对HK-2细胞TSP1 mRNA和蛋白表达的影响。Real Time PCR检测TSP1 mRNA表达,Western Blot检测TSPI蛋白表达。结果与空白对照组比较,TGF-β1（4ng／ml）明显上调HK-2细胞TSP1 mRNA和蛋白表达。与TGF-β1（4ng／ml）阳性对照组比较,中浓度和高浓度大黄酸明显抑制了TSP1 mRNA和蛋白表达。结论大黄酸能抑制TGF-β1诱导的HK-2TSP1 mRNA和蛋白表达。     

普伐他汀抑制羧甲赖氨酸修饰白蛋白诱导足细胞表达单核细胞趋化蛋白1

目的研究普伐他汀对羧甲基赖氨酸修饰白蛋白（CML-BSA）诱导的小鼠足细胞单核细胞趋化蛋白1（MCP-1）表达的干预作用。方法使用RT-PCR和ELISA方法检测MCP-1的表达水平及细胞上清液MCP-1含量。共聚焦显微镜测量对二氯荧光黄敏感的细胞内活性氧（ROS）的产量。Western印迹法和免疫组化技术检测活化的细胞外信号调节蛋白激酶（ERK）、核因子κB（NF-κB）和转录因子Sp1的表达。结果CML-BSA呈时间和浓度依赖的方式诱导MCP-1的表达。0.1或1.0 mmol/L普伐他汀可抑制CML-BSA诱导的MCP-1 mRNA和蛋白的表达。CML-BSA可迅速诱导足细胞内ROS的生成。普伐他汀不影响细胞ROS生成。CML-BSA诱导足细胞磷酸化ERK（p-ERK）表达升高,而普伐他汀可以浓度依赖方式对此加以阻断。Western印迹法和免疫组化实验结果均提示普伐他汀预处理足细胞可以阻断CML-BSA诱导的NF-κB和Sp1的易位。结论普伐他汀能够通过调节足细胞内ERK、NF-κB和Sp1信号途径,阻断CML-BSA诱导MCP-1的表达。     

系膜细胞源性肿瘤坏死因子α上调IgA肾病肾小管肝型脂肪酸结合蛋白的表达及其肾脏保护作用

目的 探讨体外近曲小管肝型脂肪酸结合蛋白（L-FABP）在IgA肾病（IgAN）中的上调机制及其对肾脏的保护作用。 方法 原代培养的小鼠系膜细胞（MC）与不同浓度的多聚IgA（AIgA）（10～250 mg/L）共孵育48 h,取上清作为AIgA-MC介质。分别应用不同浓度的AIgA、AIgA-MC介质、中和性抗肿瘤坏死因子α（TNF-α）抗体及重组鼠TNF-α刺激小鼠近曲小管上皮细胞系mProx和通过转染稳定表达人L-FABP （hL-FABP）基因的mProx (mProx-L)细胞。实时荧光定量PCR方法检测细胞中的hL-FABP和单核细胞趋化蛋白1（MCP-1）的mRNA表达。Western印迹方法检测细胞中的hL-FABP蛋白和4-羟壬烯醛 （4-HNE）修饰蛋白的表达。 结果 （1）AIgA-MC介质显著上调mProx-L细胞的hL-FABP mRNA和蛋白的表达（P < 0.01）,而AIgA刺激不能上调hL-FABP的表达。（2）中和性抗TNF-α抗体（终质量浓度为1和5 mg/L）的预孵育可以显著抑制AIgA-MC介质对hL-FABP蛋白表达的上调效应（P < 0.05和P < 0.01）。（3）重组鼠TNF-α（终质量浓度为50 和250 ng/L）呈剂量依赖性显著上调hL-FABP蛋白的表达（P < 0.01）。（4）AIgA-MC介质刺激后, mProx-L细胞4-HNE修饰蛋白和MCP-1 mRNA的表达水平显著低于mProx细胞（P < 0.05和P < 0.01）。 结论 IgAN中系膜细胞源性TNF-α可以诱导肾小管L-FABP表达的上调。肾小管高表达的L-FABP抑制了氧化应激和炎性反应,发挥了肾脏保护作用。     

Effect of heat shock protein 47 on epithelial-mesenchymal transdifferentiation induced by transforming growth factor β1 in the renal tubular epithelial cells

Objective To detect the expression of heat shock protein 47(HSP47) in renal proximal epithelial cell lines (HK-2) and to investigate the role of HSP47 in the progress of transforming growth factor β1 (TGF-β1) induced epithelial-mesenchymal transdifferentiation (EMT) in HK-2 cells. Methods HK-2 cells were exposed to TGF-β1 (0, 2.5, 5, 10 μg/L) for different time (0, 12, 24, 48 h). The expression of HSP47 was examined by Western blotting. Then HK-2 cells were exposed to 10 μg/L TGF-β1, the expressions of vimentin, zona occludens-1 (ZO-1) were examined by Western blotting and real-time PCR. Furthermore, the expressions of p-Smad3 and Smad3 were examined by Western blotting. HK-2 cells were transfected with HSP47 siRNA and siRNA negative control before exposing to TGF-β1. Then the expressions of vimentin, ZO-1 were detected by Western blotting and real-time PCR, meanwhile Western blotting for HSP47, p-Smad3 and Smad3. Results Stimulating HK-2 with TGF-β1resulted in a significant increased expression of HSP47 in time-and concentration-dependent manner (P＜0.05). Meanwhile, TGF-β1up-regulated the protein and mRNA expression of vimentin (P＜0.05), and down-regulated the protein and mRNA expression of ZO-1 (P＜0.05), all in time-dependent manner. Stimulating HK-2 with TGF-β1 resulted in phosphorylation of Smad3, which was peaked at 30 min, slightly decreased at 1 h, and then increased again between 24 and 48 h (P＜0.05). Compared to the TGF-β1group, inhibition of HSP47 expression in HK-2 up-regulated the protein and mRNA expression of ZO-1, down-regulated the protein and mRNA expression ofvimentin (P＜0.05) and down-regulated the ratio of p-Smad3/Smad3. HSP47 siRNA negative control had no significant effect on the expressions of ZO-1, vimentin and p-Smad3/Smad3 (P＞0.05). Conclusion HSP47 can promote the EMT of renal tubular epithelial cell which is possibly via the TGF-β1-Smad3 pathway.     

ERK1/2信号通路在甲状旁腺激素致人近曲小管上皮细胞分泌纤溶酶原激活物抑制剂1中的作用

目的 从体外观察ERK信号通路在甲状旁腺激素（PTH）致人近曲小管上皮细胞（HK-2）合成纤溶酶原激活物抑制物1（PAI-1）中的作用。 方法 以HK-2细胞株为研究对象,用不同浓度PTH（10-8、10-9、10-10、10-11、10-12 mol/L）作用细胞48 h,以及10-10 mol/L PTH作用细胞不同时间（12、24、36、48、72 h）,分别用RT-PCR法检测PAI-1 mRNA表达,Western印迹法检测PAI-1蛋白表达。以10-10 mol/L PTH作用细胞48 h,分别观察细胞ERK1/2抑制剂预处理前后磷酸化（p）ERK1/2、PAI-1mRNA及蛋白的变化情况。 结果 10-12 mol/L PTH可促进细胞在基因及蛋白水平合成PAI-1,随着PTH浓度逐渐上升,PAI-1mRNA及蛋白浓度均相应增加,以10-10 mol/L PTH组刺激作用最显著,分别为对照组的4.01倍和3.81倍（均P < 0.01）。但随着PTH浓度进一步增加,PAI-1mRNA及蛋白浓度却随之下降。10-10 mol/L PTH作用细胞,12 h时有少量PAI-1表达,72 h时达峰值,并呈时间依赖性,分别为0 h组的4.06倍和4.03倍（均P < 0.01）。10-10 mol/L PTH作用细胞48 h,有大量的p-ERK1/2合成（P < 0.01）,经ERK1/2抑制剂预处理后,PAI-1及ERK均显著下降（均P < 0.01）,但仍高于对照组（均P < 0.05）。 结论 ERK信号通路部分参与PTH致HK-2细胞合成PAI-1的作用。     

Role of Wnt signaling pathway on the epithelial to mesenchymal transition induced by parathyroid hormone in renal tubular epithelial cells

Objective To observe the effect of parathyroid hormone on transdifferentiation of human renal proximal tubular epithelial cell (HK-2), and to investigate the role of Wnt signaling pathway in this process. Methods The expression of α-SMA, E-cadherin mRNA and protein was detected by real-time PCR and Western blotting. After the induction of 10-10 mol/L PTH for 48 h, the Wnt pathway associated gene expression profiling was detected by quantitative PCR-microarray. The expression of Wnt4 mRNA and protein under various concentrations of PTH or after exposed to 10-10 mol/L PTH for different time was detected by real-time PCR and Western blotting. The overexpression and knock-down plasmids of Wnt4 were constructed and the expression of α-SMA, E-cadherin, Wnt4 mRNA and protein was detected by real-time PCR and western blotting after overexpression and knockdown of Wnt4. Results Compared with PTH group, the expression of α-SMA mRNA and protein in PTH+DKK1 group was significantly down-regulated, while E-cadherin mRNA and protein expression was significantly up-regulated (all P＜0.01). PTH treatment resulted in the up-regulation of 18 genes and down-regulation of 9 genes associated with Wnt pathway. Compared with control group, the expression of Wnt4 mRNA and protein increased markedly in PTH group (all P＜0.01). The expression of α-SMA mRNA and protein was significantly up-regulated and E-cadherin mRNA and protein expression was significantly down-regulated after overexpression of Wnt4 and PTH treatment (all P＜0.05), while the expression of α-SMA mRNA and protein was significantly down-regulted and E-cadherin mRNA and protein expression was significantly down-regulated after knockdown of Wnt4 and PTH treatment (all P＜0.05). Conclusions PTH-induced EMT in HK-2 cells is mediated by Wnt signal pathway, and Wnt4 might be a key gene during PTH-induced EMT.     

Inhibitory effects of rosiglitazone on lipopolysaccharide-induced inflammation in a murine model and HK-2 cells

Background: Inflammation may play an important role in the pathogenesis of kidney disease. Agonists of the peroxisome proliferator-activated receptor-γ (PPAR-γ), such as rosiglitazone, have been recently demonstrated to regulate inflammation by modulating the production of inflammatory mediators. The purpose of this study was to examine the effects of rosiglitazone on lipopolysaccharide (LPS)-induced kidney inflammation and to explore the mechanism of its renoprotection. Methods: Mice were treated with LPS with or without pretreatment with rosiglitazone. Blood urea nitrogen (BUN), creatinine levels, the urinary albumin-to-creatinine ratio, macrophage infiltration, monocyte chemoattractant protein-1 (MCP-1) expression, PPAR-γ expression, and NF-κB and PPAR-γ activity were investigated. HK-2 cells were maintained under defined in vitro conditions, treated with either rosiglitazone and/or the PPAR-γ antagonist GW9662, and then stimulated with LPS. MCP-1, IL-8, IL-6, NF-κB activity and PPAR-γ expression were investigated. Results: Compared to the LPS only group, pretreatment with rosiglitazone in vivo significantly attenuated the BUN levels macrophage infiltration, MCP-1 overexpression and NF-κB activity (p < 0.05). Rosiglitazone also restored PPAR-γ expression and protein activity, which were reduced significantly in the LPS only group (p < 0.05). Furthermore, in the LPS-stimulated HK-2 cells, rosiglitazone downregulated MCP-1, IL-8 and IL-6 expression as well as NF-κB activation and increased PPAR-γ expression (p < 0.05). These effects were diminished by GW9662. Conclusion: These results showed that pretreatment with rosiglitazone could attenuate kidney inflammation through the activation of PPAR-γ, suppression of MCP-1 overproduction and NF-κB activation. Rosiglitazone had a protective effect via a PPAR-γ-dependent pathway in LPS-treated HK-2 cells.     

miR-34b-5p promotes renal cell inflammation and apoptosis by inhibiting aquaporin-2 in sepsis-induced acute kidney injury

ObjectiveThis study was designed to uncover the mechanism of miR-34b-5p-mediated aquaporin-2 (AQP2) in sepsis-induced injury using human renal tubular epithelial cells (HK-2).MethodsSerum levels of miR-34b-5p, TNF-α, IL-1β, IL-6, serum creatinine (SCr), and blood urea nitrogen (BUN) in septic patients with acute kidney injury (AKI) and healthy controls were detected. Lipopolysaccharide (LPS) was used to induce sepsis in HK-2 cells. LPS-induced HK-2 cells were transfected with miR-34b-5p inhibitor, miR-34b-5p mimic, pcDNA3.1-AQP2, si-AQP2, miR-34b-5p inhibitor + si-NC, or miR-34b-5p inhibitor + si-AQP2. The expressions of miR-34b-5p, AQP2, Bax, Bcl-2, cleaved caspase-3, TNF-α, IL-1β, and IL-6 in HK-2 cells were detected. TUNEL staining revealed the apoptosis of HK-2 cells. Dual-luciferase reporter assay verified the binding between miR-34b-5p and AQP2.ResultsThe expression of miR-34b-5p and the inflammatory responses were augmented in septic AKI patients. miR-34b-5p was up-regulated and AQP2 was down-regulated in LPS-induced HK-2 cells. miR-34b-5p inhibition or AQP2 overexpression ameliorated apoptosis and inflammation in LPS-induced HK-2 cells. In contrast, overexpressing miR-34b-5p deteriorated LPS-induced injury in HK-2 cells. AQP2 was a downstream target of miR-34b-5p. AQP2 silencing abolished the suppressive effects of miR-34b-5p inhibition on LPS-induced apoptosis and inflammatory response in HK-2 cells.ConclusionmiR-34b-5p inhibits AQP2 to promote LPS-induced injury in HK-2 cells.     

血管紧张素1-7对高糖诱导人肾小管上皮细胞转分化的影响及其机制

目的 研究血管紧张素1-7（Ang 1-7）对高糖诱导人肾小管上皮细胞（HK-2）转分化的影响及其可能机制。 方法 培养HK-2细胞分组如下：对照组（N组）、高糖组（H组）、高糖+Ang 1-7组（A组）、高糖+Ang 1-7+A779组（D组）、高糖+吡格列酮组（P组）。Western印迹检测各组HK-2细胞过氧化物酶体增殖物激活受体γ（PPAR-γ）及α平滑肌肌动蛋白（α-SMA）的蛋白表达;实时定量PCR检测HK-2细胞PPAR-γ及α-SMA的mRNA表达;免疫荧光检测α-SMA表达。 结果 Ang 1-7可上调高糖刺激下HK-2细胞PPAR-γ蛋白及mRNA表达（P < 0.05）;抑制高糖刺激的α-SMA蛋白及mRNA表达（P < 0.05）。这种作用与PPAR-γ激动剂吡格列酮类似。给予Mas受体抑制剂A779后,Ang 1-7的上述作用可被部分抑制。 结论 Ang 1-7在体外可通过上调PPAR-γ表达,从而部分抑制高糖诱导的α-SMA表达,实现其抑制转分化的作用,而这种作用部分通过Mas受体所介导。