Role for integrin-linked kinase in mediating tubular epithelial to mesenchymal transition and renal interstitial fibrogenesis

Under pathologic conditions, renal tubular epithelial cells can undergo epithelial to mesenchymal transition (EMT), a phenotypic conversion that is believed to play a critical role in renal interstitial fibrogenesis. However, the underlying mechanism that governs this process remains largely unknown. Here we demonstrate that integrin-linked kinase (ILK) plays an important role in mediating tubular EMT induced by TGF-beta1. TGF-beta1 induced ILK expression in renal tubular epithelial cells in a time- and dose-dependent manner, which was dependent on intracellular Smad signaling. Forced expression of ILK in human kidney proximal tubular epithelial cells suppressed E-cadherin expression and induced fibronectin expression and its extracellular assembly. ILK also induced MMP-2 expression and promoted cell migration and invasion in Matrigel. Conversely, ectopic expression of a dominant-negative, kinase-dead form of ILK largely abrogated TGF-beta1-initiated tubular cell phenotypic conversion. In vivo, ILK was markedly induced in renal tubular epithelia in mouse models of chronic renal diseases, and such induction was spatially and temporally correlated with tubular EMT. Moreover, inhibition of ILK expression by HGF was associated with blockade of tubular EMT and attenuation of renal fibrosis. These findings suggest that ILK is a critical mediator for tubular EMT and likely plays a crucial role in the pathogenesis of chronic renal fibrosis.     

Angiotensin II-induced hypertrophy of cultured murine proximal tubular cells is mediated by endogenous transforming growth factor-beta.

Previous studies by our group have demonstrated that angiotensin II (ANG II), as a single factor in serum-free medium, induces cellular hypertrophy of a cultured murine proximal tubular cell line (MCT). The present study was performed to test the hypothesis that this growth effect was mediated by activation of endogenous transforming growth factor-beta (TGF-beta). Exogenous TGF-beta 1 (1 ng/ml) mimicked the growth effects observed with 10(-8) M ANG II (inhibition of DNA synthesis and induction of cellular hypertrophy). A neutralizing anti-TGF-beta antibody attenuated the ANG II-induced increase in de novo protein and total RNA synthesis as well as total protein content. This antibody also abolished the ANG II-mediated inhibition of [3H]thymidine incorporation into quiescent MCT cells. Control IgG or an unrelated antibody had no effect. A bioassay for TGF-beta using mink lung epithelial cells revealed that MCT cells treated with ANG II released active TGF-beta into the cell culture supernatant. Northern blot analysis and semi-quantitative cDNA amplification demonstrated increases in steady-state levels for TGF-beta 1 mRNA after ANG II stimulation of MCT cells, but not in a syngeneic murine mesangial cell line. Our data indicate that the ANG II-induced hypertrophy in MCT cells is mediated by synthesis and activation of endogenous TGF-beta. It is intriguing to speculate that TGF-beta may play a role in the early tubular cell hypertrophy and the subsequent interstitial scarring observed in several models of chronic renal injury that are characterized by increased activity of intrarenal ANG II.     

Characterization of vascular endothelial growth factor's effect on the activation of protein kinase C, its isoforms, and endothelial cell growth.

Vascular endothelial growth factor (VEGF) is a potent endothelial cell mitogen which mediates its effects by binding to tyrosine kinase receptors. We have characterized the VEGF-activated intracellular signal transduction pathway in bovine aortic endothelial cells and correlated this to its mitogenic effects. VEGF induced concentration- and time-dependent increases in protein kinase C (PKC) activation with a maximum of 2.2-fold above the basal level at 5 x 10(-10) M within 10 min as measured both by in situ and translocation assays. Immunoblotting analysis of PKC isoforms in cytosolic and membrane fractions indicated that after VEGF stimulation the content of Ca(2+)-sensitive PKC isoforms (alpha and betaII) was increased in the membrane fractions, whereas no changes were observed for PKC isoforms delta and epsilon. The stimulation of PKC activity by VEGF was preceded by the activation of phospholipase Cgamma (PLCgamma). This was demonstrated by parallel increases in PLCgamma tyrosine phosphorylation, [3H]inositol phosphate production, and [3H]arachidonic acid-labeled diacylglycerol formation in bovine aortic endothelial cells. In addition, VEGF increased phosphatidylinositol 3-kinase activity 2.1-fold which was inhibited by wortmannin, a phosphatidylinositol 3-kinase inhibitor, without decreasing the VEGF-induced increase in PKC activity or endothelial cell growth. Interestingly, genistein, a tyrosine kinase inhibitor, and GFX or H-7, PKC inhibitors, abolished both VEGF-induced PKC activation and endothelial cell proliferation. VEGF's mitogenic effect was inhibited by a PKC isoform beta-selective inhibitor, LY333531, in a concentration-dependent manner. In contrast, antisense PKC-alpha oligonucleotides enhanced VEGF-stimulated cell growth with a simultaneous decrease of 70% in PKC-alpha protein content. Thus, VEGF appears to mediate its mitogenic effects partly through the activation of the PLCgamma and PKC pathway, involving predominately PKC-beta isoform activation in endothelial cells.     

Cytokine-induced expression of a nitric oxide synthase in rat renal tubule cells.

Nitric oxide (NO.) has been implicated in the regulation of renal vascular tone and tubular sodium transport. While the endothelial cell is a well known source of NO(.), recent studies suggest that tubular epithelial cells may constitutively generate NO(.). An inducible isoform of nitric oxide synthase which produces far greater quantities of NO. exists in some cell types. We sought to determine whether kidney epithelial cells exposed to cytokines could express an inducible nitric oxide synthase. Primary cultures of rat proximal tubule and inner medullary collecting duct cells generated NO. on exposure to TNF-alpha and IFN-gamma. NO. production by both cell types was inhibited by NG-monomethyl-L-arginine; this inhibition was partially reversed by the addition of excess L-arginine. Stimulation of kidney epithelial cells with TNF-alpha and IFN-gamma dramatically increased the level of inducible nitric oxide synthase mRNA. In summary, renal proximal tubule and inner medullary collecting duct cells can produce NO. via expression of an inducible isoform of nitric oxide synthase.     

Parathyroid hormone stimulates the endothelial expression of vascular endothelial growth factor

Background We showed previously that parathyroid hormone (PTH) may stimulate the endothelial expression of pro‐atherosclerotic and pro‐inflammatory markers. Considering the impact of PTH on vasculature, we decided to evaluate its effect on mRNA and intra‐cellular protein expressions of endothelial vascular endothelial growth factor (VEGF) taking into account that VEGF may play a role in the pathogenesis of endothelial dysfunctions. Materials and methods Human umbilical vein cords endothelial cells (HUVEC) were stimulated for 24 h with 10^?12–10^?10 mol L^?1 PTH. The VEGF‐165 mRNA expression (critical in stimulating endothelial cell proliferation) was evaluated by RT/PCR and the intra‐cellular VEGF protein expression by flow cytometry. The pathways by which PTH may have an effect on VEGF expression were also evaluated. Results PTH (10^?10 mol L^?1) significantly increased VEGF‐165 mRNA expression (P < 0·05). The addition of 50 nmol L^?1 protein kinase C (PKC) and 10 µmol L^?1 protein kinase A (PKA) inhibitors significantly reduced the VEGF‐165 mRNA expression (P = 0·01). We also examined whether nitric oxide (NO) may be involved in the PTH‐induced stimulation of VEGF‐165 expression. Pre‐treatment of the cells with 200 µmol L‐nitro arginine methyl ester (L‐NAME, NO synthase inhibitor) was found to inhibit VEGF‐165 mRNA expression (P = 0·006). VEGF protein could not be detected in the medium of HUVEC but it was present in the cell cytoplasm. PTH had no significant effect on cytoplasmatic VEGF protein expression. Conclusion The stimulatory effect of PTH on endothelial VEGF‐165 mRNA expression is partly through PKC and PKA pathways and is also NO dependent.     

血管内皮生长因子与单侧输尿管梗阻大鼠肾间质纤维化程度的相关性研究

目的观察单侧输尿管梗阻大鼠肾组织中血管内皮细胞生长因子(VEGF)的表达水平,并探讨VEGF与肾间质纤维化的相关性。方法将42只雄性SD大鼠按照随机原则分为假手术组和单侧输尿管梗阻模型组(UUO组),每组21只大鼠。术后第5、15、25天2组各处死7只大鼠,采集血清和24 h尿液,检测血肌酐、尿素氮、24 h尿蛋白定量,留取梗阻侧肾脏进行病理学检查,使用免疫组织化学方法检测VEGF在肾组织的表达水平,观察VEGF表达水平与肾间质纤维化程度及肾功能的相关性。结果术后第5、15、25天,UUO组血肌酐水平与同期假手术组相比明显升高,差异均有统计学意义(P<0.05);术后第5、15天,UUO组尿素氮水平高于同期假手术组,差异有统计学意义(P<0.05)。术后第5天UUO组24 h尿蛋白定量与假手术组比较,差异无统计学意义(P>0.05),但术后第15、25天24 h尿蛋白定量均高于假手术组,差异有统计学意义(P<0.05)。病理学检查结果显示,假手术组大鼠在术后第5、15、25天,肾小管上皮细胞可见较多VEGF蛋白表达;UUO组大鼠术后第5天肾小管间质开始出现少量炎性细胞浸润,少数肾小管出现扩张,部分肾小管可见VEGF蛋白表达,第15、25天肾小管间质见较多炎性细胞浸润,VEFG蛋白表达量呈逐渐降低趋势,术后第25天大量炎性细胞浸润,仅见少许肾小管VEGF呈弱表达,肾间质纤维化区域无VEGF表达。在UUO组中,术后第5天VEGF表达与24 h尿蛋白定量呈正相关(P<0.05);在术后第5、15、25天,VEGF的表达与血肌酐及尿素氮水平均无明显相关性(P>0.05)。结论在单侧输尿管梗阻大鼠肾间质纤维化模型中,VEGF表达量随肾间质纤维化程度加重逐渐减低,肾间质弥散性纤维化时,肾组织的VEGF几乎无表达,提示VEGF在肾间质纤维化发生发展中可能起重要作用。     

西罗莫司对慢性移植肾肾病肾组织转化生长因子β1和血管内皮生长因子表达的影响(英文)

背景:西罗莫司对肾移植术后急性排斥反应的防治产生重要作用,同时,有研究发现它可抑制血管平滑肌细胞的增殖和迁徙,对慢性排斥反应以及慢性移植肾肾病产生防治作用,但具体的机制尚不清楚.目的:探讨西罗莫司对慢性移植肾肾病肾组织转化生长因子和血管内皮生长因子表达的影响.方法:选择原发性肾病首次尸肾移植者60例,随机分为两组:西罗莫司组和硫唑嘌呤组各30例,分别采用西罗莫司+环孢素A+激素,硫唑嘌呤+环孢素A+激素治疗,西罗莫司首次负荷剂量为6mg,2周内2mg/d,2周后改为1.0～2.0 mg/d,环孢素A为5.0～7.0 mg/d,硫唑嘌呤为50～100 mg/d,激素为15～0 mg/d.术后2年时,对移植肾进行活检.观察移植肾组织转化生长因子β1和血管内皮生长因子表达情况,并观察肝功能、血肌酐浓度、急性排斥反应发生率、人/肾存活率.结果与结论:随访2年,西罗莫司组于术后1,3,12个月的环孢素剂量明显低于硫唑嘌呤组,但是两组之间的血环孢素A的谷值浓度没有明显差异.硫唑嘌呤组中,转化生长因子β1表达主要分布于近曲小管,部分可见肾小球以及间质血管;大部分移植肾组织近曲小管呈阳性表达,线型分布于刷状缘,部分呈阳性表达.部分患者肾小球脏层上皮细胞呈节段性阳性表达.内皮细胞及系膜偶见阳性表达.西罗莫司组中,转化生长因子β1在近曲小管的表达则明显减弱,肾小球和间质血管无明显改变.硫唑嘌呤组中血管内皮生长因子表达主要见于肾小球脏层上皮细胞,部分病例也可见于内皮细胞及系膜细胞,间质血管呈阳性表达,主要分布于内皮层.西罗莫司组,肾小球、间质血管染色均明显减少.与硫唑嘌呤组比较,西罗莫司组人/肾存活率高、移植肾组织转化生长因子β1和血管内皮生长因子表达明显降低.结果表明,西罗莫司可降低移植肾组织转化生长因子β1和血管内皮生长因子表达,减缓慢性移植肾肾病的进展,延长移植肾存活时间.     

Retracted Article: TMEM88 inhibits fibrosis in renal proximal tubular epithelial cells by suppressing the transforming growth factor-β1/Smad signaling pathway

Transmembrane protein 88 (TMEM88) belongs to a member of the TMEM family, and was reported to be involved in fibrogenesis. However, the biological role of TMEM88 in renal fibrosis has not been elucidated. Therefore, the objective of this study was to investigate the effect of TMEM88 on cell proliferation and extracellular matrix (ECM) accumulation in a TGF-β1-induced human renal proximal tubular epithelial cell line (HK2). Our results showed that TMEM88 was downregulated in renal fibrotic tissues and TGF-β1-treated HK2 cells. In addition, TMEM88 overexpression inhibited TGF-β1-induced cell proliferation and migration in HK2 cells. Furthermore, TMEM88 overexpression reduced the production of α-SMA, collagen I, and collagen III in TGF-β1-stimulated HK2 cells. Mechanistically, TMEM88 overexpression suppressed the phosphorylation status of Smad2 and Smad3 in TGF-β1-stimulated HK2 cells. In conclusion, data from our experiments demonstrate that TMEM88 plays a pivotal role in the pathological process of renal fibrosis. TMEM88 inhibited fibrosis in renal proximal tubular epithelial cells by suppressing the TGF-β1/Smad signaling pathway.

Transmembrane protein 88 (TMEM88) belongs to a member of the TMEM family, and was reported to be involved in fibrogenesis.     

灯盏花乙素干预缺血再灌注损伤人脐静脉内皮细胞血管内皮生长因子与蛋白激酶Cε的表达

背景:有关灯盏花乙素的研究多集中在神经细胞、神经元及平滑肌细胞上,但对血管内皮细胞的作用研究尚少。目的:观察灯盏花乙素预处理后对人脐静脉内皮细胞缺血再灌注损伤后血管内皮生长因子与蛋白激酶Cε表达的影响。方法:体外培养的人脐静脉内皮细胞,分别设立对照组,模型组和及灯盏花乙素高、中、低剂量组。将人脐静脉内皮细胞予缺氧缺糖3h/复氧糖5或24h;灯盏花乙素高、中、低剂量组分别加1×10-5,1×10-6,1×10-7mol/L灯盏花乙素孵育30min,然后予缺血再灌注处理。实验结束后取细胞裂解液用Westernblot检测血管内皮生长因子、蛋白激酶Cε的蛋白表达。结果与结论:缺血3h再灌注5及24h,较对照组,模型组血管内皮生长因子的表达降低,细胞颗粒部分蛋白激酶Cε的表达明显增加。灯盏花乙素能促进缺血3h再灌注5h人脐静脉内皮细胞血管内皮生长因子的表达,尤其以灯盏花乙素高剂量和中剂量组明显,但对蛋白激酶Cε的表达没有影响。     

The role of vascular endothelial growth factor in the kidney in health and disease

Vascular endothelial growth factor (VEGF) is a potent endothelial cell mitogen, angiogenic factor and enhancer of vascular permeability. Expressed in the epithelial cells of the developing glomerulus and tubular epithelium, VEGF plays an important role in the development and maintenance of the early vasculature of the kidney. Here, we review the available literature regarding the expression and function of VEGF both in the developing and healthy adult kidney. Furthermore, we highlight how VEGF expression is altered in the diseased kidney and how this modulated expression may impact on and reflect underlying functional changes occurring during the disease process. As discussed, many controversial issues remain, particularly concerning the role of VEGF in the diseased kidney. That VEGF has been proposed as a potential future therapeutic target for the management of some renal diseases requires first that the precise role of VEGF in the normal kidney and various renal pathologies be further and more clearly defined.     

灯盏花乙素干预缺血再灌注损伤人脐静脉内皮细胞血管内皮生长因子与蛋白激酶Cε的表达

背景：有关灯盏花乙素的研究多集中在神经细胞、神经元及平滑肌细胞上,但对血管内皮细胞的作用研究尚少。目的：观察灯盏花乙素预处理后对人脐静脉内皮细胞缺血再灌注损伤后血管内皮生长因子与蛋白激酶Cε表达的影响。方法：体外培养的人脐静脉内皮细胞,分别设立对照组,模型组和及灯盏花乙素高、中、低剂量组。将人脐静脉内皮细胞予缺氧缺糖3h/复氧糖5或24h;灯盏花乙素高、中、低剂量组分别加1×10^-5,1×10^-6,1×10^-7mol/L灯盏花乙素孵育30min,然后予缺血再灌注处理。实验结束后取细胞裂解液用Westernblot检测血管内皮生长因子、蛋白激酶Cε的蛋白表达。结果与结论：缺血3h再灌注5及24h,较对照组,模型组血管内皮生长因子的表达降低,细胞颗粒部分蛋白激酶Cε的表达明显增加。灯盏花乙素能促进缺血3h再灌注5h人脐静脉内皮细胞血管内皮生长因子的表达,尤其以灯盏花乙素高剂量和中剂量组明显,但对蛋白激酶Cε的表达没有影响。     

Regulation of dedifferentiation and redifferentiation in renal proximal tubular cells by the epidermal growth factor receptor

Repair of injured renal epithelium is thought to be mediated by surviving renal proximal tubular cells (RPTC) that must dedifferentiate to allow the proliferation and migration necessary for epithelial regeneration. RPTC then redifferentiate to restore tubular structure and function. Current models suggest that epidermal growth factor receptor (EGFR) activation is required for dedifferentiation characterized by enhanced vimentin expression, decreased N-cadherin expression, spindle morphology, and loss of apical-basal polarity after injury. Because an in vitro model of RPTC redifferentiation has not been reported, and the mechanism(s) of redifferentiation has not been determined, we used rabbit RPTC in primary cultures to address these issues. H2O2 induced the dedifferentiated phenotype that persisted >48 h; redifferentiation occurred spontaneously in the absence of exogenous growth factors after 72 to 120 h. Phosphorylation of two tyrosine residues of EGFR increased 12 to 24 h, peaked at 24 h, and declined to basal levels by 48 h after injury. EGFR inhibition during dedifferentiation restored epithelial morphology and apical-basal polarity, and it decreased vimentin expression to control levels 24 h later. In contrast, exogenous epidermal growth factor addition increased vimentin expression and potentiated spindle morphology. p38 mitogen-activated protein kinase (MAPK) and transforming growth factor (TGF)-beta receptor inhibitors did not affect redifferentiation after H2O2 injury. Similar results were observed in a mechanical injury model. These experiments represent a new model for the investigation of RPTC redifferentiation after acute injury and identify a key regulator of redifferentiation: EGFR, independent of p38 MAPK and the TGF-beta receptor.     

Quantitative analysis of gene expressions of vascular endothelial growth factor-related factors and their receptors in renal cell carcinoma

Vascular endothelial growth factor (VEGF)-related factors are believed to regulate angiogenesis, an essential event in the growth of solid tumors. In this study, we investigated the expression of VEGF-related factor genes (VEGF, VEGF-B, and VEGF-C) and their receptor genes (VEGFR-1 and VEGFR-2) in renal cell carcinoma (RCC). There were significant differences in the expression level of VEGF, VEGFR-1 and VEGFR-2 between RCC and the corresponding normal renal tissue. The expression level of VEGF in the tumor tissue significantly correlated with those of VEGFR-1 and VEGFR-2. Expression levels VEGF-B and VEGF-C genes were not significantly different between RCC and normal renal tissue. A moderate to high protein expression for VEGF, VEGFR-1, and VEGFR-2 was observed in both the tumor cells and the endothelial cells, whereas the protein expression was low for VEGF-B and VEGF-C. The present results suggested that VEGF and its receptors VEGFR-1 and VEGFR-2 cooperates to play a crucial role in the angiogenesis of RCC, while VEGF-B and VEGFR-C may not. Furthermore, since VEGFR-1 and VEGFR-2 proteins were expressed in the tumor cells as well as in the endothelial cells, these receptors may also be responsible for the progression of RCC.     

高糖上调肾小管上皮细胞Toll样受体2的表达

目的探讨葡萄糖对大鼠肾小管上皮细胞Toll样受体2(TLR2)表达的影响。方法大鼠近端肾小管上皮细胞(NRK52E细胞)用含10%胎牛血清(FBS)的DMEM培养液传代培养。根据培养液葡萄糖浓度分组。培养24小时后用Western blot及RT-PCR方法检测各组肾小管上皮细胞TLR2蛋白及单核细胞趋化蛋白-1(MCP-1)mRNA的表达。结果肾小管上皮细胞(NRK52E细胞)表达TLR2,高浓度葡萄糖可增加肾小管上皮细胞TLR2的表达。高浓度葡萄糖刺激肾小管上皮细胞表达MCP-1 mRNA显著上调。结论高浓度葡萄糖上调肾小管上皮细胞TLR2的表达,诱导炎症趋化因子增加。     

Interleukin-1beta-induced transdifferentiation of renal proximal tubular cells is mediated by activation of JNK and p38 MAPK

Interleukin (IL)-1beta induces renal tubular epithelial cells to transdifferentiate to myofibroblasts, which express alpha-smooth muscle actin (alpha-SMA). To understand the signal transduction mechanisms involved in transdifferentiation, we examined the roles of mitogen-activated protein kinases (MAPKs) in IL-1beta-stimulated alpha-SMA expression and cell migration in the HK-2 human renal proximal tubular cell line. IL-1beta induced the transdifferentiation of renal proximal tubular cells, which was characterized by upregulated expression of alpha-SMA and increased cell migration. In addition, IL-1beta increased the activity of the three members of the MAPK family, ERK, JNK and p38 MAPK, in these cells. Both SP600125, a specific inhibitor of JNK, and SB203580, a specific inhibitor of p38 MAPK, suppressed the IL-1beta-induced expression of alpha-SMA and cell migration, but these effects were not observed with PD98059, a specific inhibitor of ERK. These results suggest that IL-1beta-induced HK-2 cell transdifferentiation is mediated, at least in part, through the activation of the JNK and p38 MAPK signaling pathways.     

白细胞介素-1β在人肾小管上皮细胞转分化中的作用及Janus激酶2抑制剂AG490的影响

目的 探讨Janus激酶2抑制剂AG490对白细胞介素-1β(IL-1β)诱导人肾小管上皮细胞转分化的影响. 方法 将体外培养人肾近曲小管上皮细胞株(HKCs)分为空白对照组、IL-1β(5 ng/ml)刺激组及AG490干预组(IL-1β 5 ng/ml+AG490 10 μmol/L).分别于处理后24、48、72 h收集细胞,采用免疫细胞化学染色和蛋白质免疫印迹法(Western blotting)检测细胞角蛋白-18(CK-18)、α-平滑肌肌动蛋白(α-SMA)蛋白表达. 结果 正常肾小管上皮细胞内其自身标志物CK-18高表达(1.25±0.08),而α-SMA表达很少(0.17±0.01).IL-1β刺激组随刺激时间延长CK-18表达逐渐减少(24 h:0.69±0.04,48 h:0.52±0.03,72 h:0.30±0.01),而α-SMA蛋白合成逐渐增加(24 h:0.56±0.04,48 h:1.05±0.07,72 h:1.43±0.07),与空白对照组比较差异均有统计学意义(均P＜0.05).AG490干预能使CK-18的表达逐渐恢复(24 h:1.07±0.07,48 h:0.93±0.06,72 h:0.83±0.06),并减弱IL-1β对肾小管上皮细胞α-SMA蛋白的诱导作用(24 h:0.33±0.01,48 h:0.52±0.01,72 h:0.61±0.04),且作用显著(均P＜0.05).免疫细胞化学染色观察结果与其一致. 结论 炎症因子IL-1β通过降低肾小管上皮细胞CK-18表达,上调α-SMA表达,促使肾小管上皮细胞转分化为肌成纤维细胞;Janus激酶2抑制剂AG490能部分阻断IL-1β对肾小管上皮细胞的促转分化作用.     

Inhibition of murine nephritogenic effector T cells by a clone-specific suppressor factor.

We have used a murine model of organ-specific autoimmunity to characterize therapeutic modalities capable of down-regulating the cellular limb of the autoimmune response. Murine interstitial nephritis is an autoimmune disease mediated by tubular antigen-specific CD8+ nephritogenic effector T cells which are delayed-type hypersensitivity (DTH) reactive and cytotoxic to renal epithelial cells. Previous studies have demonstrated that disease can be suppressed with experimentally induced populations of T cells (Ts1 and Ts2 cells) obtained after injection of tubular antigen-coupled splenocytes into syngeneic mice. As the target of Ts2 is the CD8+ effector T cell, we have evaluated its effects on nephritogenic effector T cell clones isolated from diseased animals. Our studies demonstrate that soluble proteins expressed by Ts2 cells (TsF2) specifically abrogate the DTH, cytotoxic, and nephritogenic potential of M52 cells, although T cell receptor and IL-2 receptor expression are unchanged in these unresponsive M52 clones. TsF2-induced inhibition is dependent on new mRNA and protein synthesis. In a cytotoxic clone, M52.26, exposure to TsF2 induces expression of TGF-beta 1 which is, in turn, required for inhibition of cytotoxicity and nephritogenicity. Our studies are consistent with TGF-beta 1 behaving, at least in some T cells, as a nonspecific final effector of clone-specific suppression.     

低氧诱导因子1α基因修饰脂肪干细胞修复小鼠急性肾损伤

背景：干细胞移植为肾损伤的治疗提供了一个新的途径,治疗基因转染干细胞可增强对疾病的治疗效果。目的：探讨低氧诱导因子1α基因修饰的脂肪源性干细胞移植对急性肾损伤小鼠肾脏结构和功能的影响。方法：连续2d向BALB/C裸鼠腹腔注射10mg/kg顺铂诱导急性肾损伤小鼠模型。造模24h后经小鼠尾静脉注射含1×105个脂肪源性干细胞或转染低氧诱导因子1α的脂肪源性干细胞的细胞悬液,3d后留取小鼠血液及肾组织标本进行实验。以注射200μL生理盐水的急性肾损伤小鼠作为模型对照,以正常小鼠作为正常对照。结果与结论：脂肪源性干细胞干预后急性肾损伤小鼠血清肌酐、尿素氮水平降低,肾组织病理改变及肾小管上皮细胞的凋亡病变减轻,肾组织炎症因子RANTES、肿瘤坏死因子α表达降低,白细胞介素10表达升高;其中低氧诱导因子1α基因修饰的脂肪源性干细胞对肾组织细胞凋亡及炎症因子表达作用更明显。免疫荧光染色可见移植的脂肪源性干细胞的存活,但未见其向肾小管上皮细胞转化。结果表明脂肪源性干细胞移植可改善急性肾损伤小鼠的肾脏结构和功能,经低氧诱导因子1α基因修饰后的脂肪源性干细胞作用更显著。