姜黄素对TGF-β1诱导人肾小管上皮细胞转分化及分泌细胞外基质成分的影响

目的：通过研究姜黄素（curcumin,Cur）对转化生长因子-β1（TGF-β1）诱导人肾小管上皮细胞（HK-2）转分化及分泌细胞外基质（ECM）成分的影响,探讨姜黄素在防治肾小管-间质纤维化方面可能的作用机制。方法：应用不同浓度Cur处理经TGF-β1诱导活化的HK-2细胞,通过显微镜观察细胞形态改变,免疫组化技术检测α-平滑肌肌动蛋白（α-SMA）和E-钙黏蛋白（E-cadherin）的表达;应用酶联免疫吸附法（ELISA）检测细胞培养上清Ⅰ型胶原（ColⅠ）、Ⅲ型胶原（ColⅢ）和纤连蛋白（FN）的分泌。结果：（1）正常HK-2细胞表达E-cadherin,不表达α-SMA,经TGF-β1刺激后细胞表型发生转变,E-cadherin的表达明显减弱,α-SMA表达明显增强;（2）不同浓度Cur组与单纯TGF-β1刺激组相比α-SMA的表达有所减弱,而E-cadherin的表达增强;（3）不同浓度Cur抑制了ColⅠ、ColⅢ和FN的分泌,与单纯TGF-β1刺激组相比有统计学差异（P〈0.05）。结论：姜黄素能抑制TGF-β1诱导人肾小管上皮细胞转分化及细胞外基质成分ColⅠ、ColⅢ和FN的合成,在一定程度上具有防治肾小管-间质纤维化的作用。     

肝细胞生长因子对人肾小管上皮细胞转分化抑制作用初步研究

目的：晚近研究提示肝细胞生长因子（hepatocyte growth factor,HGF)具有减轻实验性肾间质纤维化的作用，但其机制尚不十分清楚；本研究目的在于探讨HGF对人肾小管上皮细胞（HKC）转分化的作用。方法：将体外培养的HKC细胞分为：（1）无血清培养对照组；（2）阳性对照组（MCP－1＋AAⅠ）；（3）HGF组（HGF浓度为0.01,0.1,1.0,10.0ng/ml);(4)MCP-1 AAⅠ HGF组（HGF浓度0.1,1.0,10.0ng/ml)。应用间接免疫荧光法检测HKC细胞内α-平滑肌肌动蛋白（α-SMA）、波形蛋白、角蛋白表达的变化。应用流式细胞技术检测α-SMA（＋）的HKC细胞百分数。结果：不同浓度HGF分别作用于HKC细胞48h后，经间接免疫荧光法测定该组HKC细胞角蛋白、波形蛋白及α－SMA抗原表达,与无血清对照组均无显著差异；流式细胞术测得HGF组α-SMA表达阳性HKC细胞百分数，与无血清对照组（平均为3.1%)也无显著差异（P＞0.05)。MCP－1＋AAⅠ培养HKC48h后α－SMA（＋）的HKC细胞平均百分数为85.6%。MCP－1＋AAⅠ＋HGF（0.1,1.0,10.0ng/ml)培养HKC48h后，α－SMA（＋）的HKC细胞百分数分别为26.7%，2.0%,13.6%，比阳性对照组明显下降（P＜0.05)。结论：（1）HGF对正常HKC细胞分化无明显影响；（2）HGF对某些因素诱导下发生的增强的HKC细胞转化可能具有显著抑制作用。     

Transdifferentiation of pancreatic α-cells into insulinsecreting cells: From experimental models to underlying mechanisms

Pancreatic insulin-secreting β-cells are essential regulators of glucose metabolism. New strategies are cur-rently being investigated to create insulin-producing β cells to replace deficient β cells, including the differentiation of either stem or progenitor cells, and the newly uncovered transdifferentiation of mature non-β islet cell types. However, in order to correctly drive any cell to adopt a new β-cell fate, a better understanding of the in vivo mechanisms involved in the plasticity and biology of islet cells is urgently required. Here, we review the recent studies reporting the phenomenon of transdifferentiation of α cells into β cells by focusing on the major candidates and contexts revealed to be involved in adult β-cell regeneration through this process. The possible underlying mechanisms of transdifferentiation and the interactions between several key factors involved in the process are also addressed. We propose that it is of importance to further study the molecular and cellular mechanisms underlying α- to β-cell transdifferentiation, in order to make β-cell regeneration from α cells a relevant and realizable strategy for developing cell-replacement therapy.     

白细胞介素1β诱导肾小管上皮细胞转分化及其对细胞骨架的影响

目的:观察白细胞介素1β(IL-1β)诱导肾小管上皮细胞转分化及其对细胞骨架的调节作用。方法:选择永生化的大鼠肾小管上皮细胞株NRK52E,经体外培养后以IL-1β(30μg/L)分别诱导3天及6天,观察细胞形态;RT-PCR半定量检测细胞α-平滑肌动蛋白(α-SMA)和细胞骨架成分β-actin、α-tubulin的mRNA表达;免疫荧光染色观察α-SMA蛋白表达及骨架蛋白β-actin、α-tubulin在细胞内的分布及排列。结果:培养的NRK52E细胞经IL-1β体外诱导3天及6天后,细胞中α-SMA mRNA及蛋白表达水平与相应的对照组细胞比较明显增多(P0.001),提示NRK52E上皮细胞出现了表型转化,此时培养细胞的形态也发生了改变,由典型的多边铺路石样变为成纤维细胞样,并有多个突起,细胞骨架蛋白β-actin mRNA的表达也稍有增多(P0.05);其蛋白的分布排列也发生了改变,由胞膜转移至核周及胞浆,形成束状纤维样结构。但IL-1β诱导组细胞的另一个骨架蛋白α-tubulin mRNA表达和分布与对照组比较无明显不同。结论:IL-1β能够诱导体外培养的NRK52E细胞转分化,此过程中细胞形态变为成纤维细胞样,多突起;骨架蛋白β-actin也表达增加,并出现了骨架重建;而α-tubulin在此过程中则没有明显变化。     

Systematic neuronal and muscle induction systems in bone marrow stromal cells: the potential for tissue reconstruction in neurodegenerative and muscle degenerative diseases

Because bone marrow stromal cells (MSCs) are easily accessible from both healthy donors and patients and can be expanded on a therapeutic scale, they have attracted attention for cell-based therapy. Benefits of MSCs have been discussed mainly from two aspects: one is their tissue protective and immunomodulatory effects, and the other is their capability under specific manipulations to differentiate into various cell types. In this review, their differentiation into functional neural and muscle cell lineages is the focus, and their potential to the application for tissue reconstruction in neurodegenerative and muscle degenerative diseases is discussed.     

Hepatogenic differentiation of human mesenchymal stem cells from adipose tissue in comparison with bone marrow mesenchymal stem cells

INTRODUCTIONMost liver diseases lead to hepatocyte dysfunction with the possibility of eventual organ failure. The replacement of diseased hepatocytes and the stimulation of endogenous or exogenous regeneration by stem cells are the main aims of liver-dir…     

外源性结缔组织生长因子对肾小管上皮细胞的转分化和胶原合成效应

目的：大量研究表明内源性结缔组织生长因子(CTGF)在肾小管间质纤维化(TIF)进程中发挥了重要作用,为进一步阐明外源性CTGF的作用机制,该实验探讨了重组人结缔组织生长因子(rhCTGF)刺激对人肾小管上皮细胞(HK2)转分化和胶原合成的作用。方法：rhCTGF 5 ng/mL刺激HK2细胞,用倒置显微镜观察细胞形态学变化,同时在刺激后0,3,6,12,24,48 h各点收集细胞,RT-PCR检测上皮细胞钙粘蛋白(E-cadherin)、α-平滑肌肌动蛋白(α-SMA)、胶原Iα1(Col Iα1)和胶原IVα1(Col IVα1)mRNA表达变化。结果：rhCTGF 5 ng/mL刺激使HK2细胞形态由椭圆形转为梭形,下调E-cadherin mRNA表达,上调-αSMA mRNA表达,但对Col Iα1和Col IVα1mRNA表达没有影响。结论：外源性CTGF能导致HK2细胞转分化,但不能促进其胶原合成。     

Bone marrow-derived stem cells and "plasticity"

Studies describing plasticity of somatic stem cells have become a focus of interest because clinical applications in the treatment of degenerative diseases would be at hand. In particular, bone marrow-derived cells and their potential to contribute to skeletal and cardiac muscle, liver, neurons and epithelium have recently been studied extensively. Nevertheless, results of these studies have not always been consistent with each other, and yet it remains to be resolved whether plasticity of adult stem cells truly exists. This review will discuss the role of bone marrow-derived stem cells in the field of experimental and clinical plasticity studies. Observations compatible with the concept of stem cell plasticity will be weighed against limitations of the experimental systems employed.     

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。