Smad4 and ERK2 stimulated by transforming growth factor beta1 in rhabdomyosarcoma

Background Transforming growth factor beta (TGF-beta) plays an essential role in the regulation of normal physiologic processes of cells. TGF-beta has been shown to regulate several mitogen-a ctivated protein kinases (MAPK) pathways in several epithelial cells. However, the effects of TGF-beta on soft tissue sarcoma are seldom reported. Our previous studies suggested that there should be some other signal transduction pathways besides Smads, which are important to regulate the growth of human embryonal rhabdomyosarcoma (RMS) cells. In the present study, we examined the expression and functional relations of extracellular signal-regulated kinase 2 (ERK2) and Smad4 in human RMS tissue and a RMS cell line, RD.Methods RD cells and normal human primary skeletal myoblasts (Mb) were treated with TGF-beta1 to establish the expression profile of ERK2 at the mRNA and protein levels detected by RT-PCR and immunofluorescence.Immunohistochemistry was used to detect the expression of ERK2 and Smad4 in 50 tissue specimens of human RMS and 23 specimens of normal skeletal muscles. Follow-up of specimens was performed 6 months to 70 months later.Results RD cells and human RMS tissues showed the higher expression of ERK2 and Smad4 than the normal control,either the protein level or the mRNA level. And, exogenous TGF-beta1 stimulation can lead to higher expression of ERK2and its nuclear translocation, so TGF-beta1 can also activated MAPK (ERK2) pathway, resulting in a sustained activation of ERK2 for at least 2 hours. Immunohistochemistry analysis, however, showed that there was no correlation between ERK2 and Smad4 protein. The overexpression of ERK2 and Smad4 had no indicative effects on histological subtypes,histological grading, gender, age, and prognosis.Conclusions In RMS, signaling of TGF-beta1 from cell surface to nucleus can also be directed through the MAPK (ERK2) pathway besides the TGF-beta1/Smads pathway. The activation of ERK2 by TGF-beta1 may be Smad4independent. Moreover, there may be some other tanglesome relationships between the TGF-beta1/Smads pathway and the MAPK pathway which takes part in the development, invasion and metastasis of tumor cells.     

The role of connective tissue growth factor, transforming growth factor β1 and Smad signaling pathway in cornea wound healing

The cornea is a highly specialized and unique organ in the human body. Its main function is to project light from the external environment onto the retina, and it has a specific transparency to perform its function properly. The transparency and integrity of the cornea is of vital importance. The corneal wound, especially laceration deep to Bowman＇s membrane and stroma, which will inevitably cause scar formation, may cause the degeneration or even loss of sight.     

转化生长因子β1与骨生化指标和腰椎骨密度间的关系

目的 探讨转化生长因子（TGF-β1）与骨形成和骨吸收指标之间的关系；它与腰椎正位骨密度间是否有联系。方法 用ELISA法测定TGF-β1，血清骨特异性碱性磷酸酶（sBAP）和血清Ⅰ型胶原羧基末端肽（sCTX）的值，同时用双能X线骨密度仪测定腰椎正位的骨密度。结果 TGF-β1与sBAP和sCTX呈反向变化，而与腰椎正位骨密度的变化相一致；校正体重指数的影响后，TGF-β1与sBAP和sCTX存在负相关，相关系数分别为-0．2946和-0．1104；与腰椎正位的骨密度间存在良好的正相关；TGF-β1在第1和第2四分位数之间、第3和第4四分位数之间时腰椎正位的骨密度差异无显著性（P〉0．05）。结论 TGF-β1能动态的反映骨转换的变化情况，但在反映骨转换变化的敏感性方面低于经典的骨转换指标。TGF-β1受绝经因素的影响较大，与雌激素缺乏所导致的绝经后骨质疏松有关。     

氟伐他汀对放射性肺损伤TGF-β1的影响

目的探讨氟伐他汀(fluvastatin)对放射性肺损伤TGF-β1表达的影响. 方法将SD大鼠随机分为对照组、单纯照射组和氟伐他汀防治组,防治组于照射前1 wk以氟伐他汀20 mg*kg-1灌胃,1次*d-1, 直至实验结束.其他组灌服生理盐水.直线加速器全胸部照射,单次剂量为20 Gy,照后5,15,30和60 d剪开胸腔, 取肺组织做病理切片,并作TGF-β1免疫组化染色, 光镜下观察染色结果. 结果放疗组显示随着照射后时间延长, TGF-β1在肺组织表达逐渐增强, 氟伐他汀防治组显示TGF-β1的表达不随病情发展而增强. 与各时间点放射组相比明显减弱. 结论氟伐他汀能明显减弱TGF-β1表达,为防治放射性肺损伤提供了实验依据.     

Influence of Exogenous TGFβ1 on the Expression of Smad2 and Smad3 in Rat Bone Marrow-derived Mesenchymal Stem Cells

The expression of Smad2 and Smad3 and the influence of exogenous transforming growth factorβ1 (TGFβ1) on them in rat bone marrow-derived mesenchymal stem cells (MSCs) cultured in vitro were investigated. The effects of different concentrations of TGFβ1 on cell proliferation and ALP activity were detected by MTT and PNPP in MSCs respectively. The expression of Smad2 and Smad3 and the influence of exogenous TGFβ1 on them were also examined by immunocytochemistry and Western blot assays. The exogenous TGFβ1 induced a dose-dependent decrease in cell proliferation and a dose-dependent increase in ALP activity, which plateaued at 5 ng/ml. Smad2 and Smad3 proteins were detected only in the cytoplasm in the absence of TGFβ1 and TGFβ1 could stimulate the translocation of them from the cytoplasm to the nucleus. The total amount of Smad2 protein remained unchanged before and after TGFβ1 treatment (P＞0.05). The expression levels of Smad3 remained unchanged after 3 h and 6 h treatment (P＞0. 05), but decreased markedly after 24 h treatment (P＜0.05). It was concluded that TGFβ1 is a latent osteoinductive factor involved in osteoblastic differentiation. Both Samd2 and Smad3 mediate TGFβ1 signaling as downstream mediators in MSCs. The biological output of TGFβ1 triggering the osteoblastic differentiation could be entirely determined by Smad3 in MSCs.     

过氧化物酶增殖物激活受体γ抑制大鼠肝星状细胞中转化生长因子-β1诱导的结缔组织生长因子表达

目的 探讨过氧化物酶增殖物激活受体γ(PPARγ)对大鼠肝星状细胞(HSC)中转化生长因子-β1(TGF-β1)诱导的结缔组织生长因子(CTGF)表达的抑制作用.方法 常规培养大鼠HSC,预先给予或不给予PPARγ特异性拮抗剂GW9662处理,再经系列浓度的PPARγ天然配体(15-d-PGJ2)或合成配体(GW7845)及TGF-β1序贯作用后,通过半定量RT-PCR及Western-blotting分析CTGF表达状况,透射电镜观察HSC形态学变化.结果 15-d-PGJ2和GW7845可显著抑制HSC中TGF-β1诱导的CTGF表达(同时在转录和转录后水平),且PPARγ配体对CTGF表达的抑制作用可被GW9662部分或完全逆转,说明此种抑制效应确由PPARγ所介导;电镜观察亦显示HSC由活化态向静息态的形态学转变.结论 PPARγ活化可显著抑制HSC中TGF-β1诱导的CTGF表达,提示PPARγ可作为逆转肝纤维化治疗的新的有效靶点.

Abstract：

Objective To investigate the effect of peroxisome proliferator-activated receptor gamma(PPARγ)activation on transforming growth factor betal(TGF-β1)-induced connective tissue growth factor(CTGF)expression in rat hepatic stellate cells(HSCs).Methods Cultured HSCs with or without PPARγ-specific antagonist GW9662 treatment prior to the addition of an increasing amount of PPARγ natural ligand(15-d-PGJ2)or synthetic ligand(GW7845)were stimulated with TGF-β1.The mRNA and protein levels of CTGF expression were detected by semi-quantitative RT-PCR and Western blotting,respectively.The morphological changes of the HSC were obgerved by electron microscope.Results 15-d-PGJ2 and GW7845 significantly inhibited TGF-β1-induced CTGF expression at both mRNA and protein levels in HSCs, and the inhibitory effect was dramatically,if not completely,abolished by pretreatment with GW9662,suggesting that the inhibition was mediated by PPARγ. Morphological observation revealed that PPARγactivation caused obvious changes of HSCs from activated to quiescent phenotypes.Conclusion PPARγ ligand shows potent inhibitory effect on TGF-β1-induced CTGF expression in rat HSCs,suggesting its potential as a candidate agent for treatment and prevention of hepatic fibrosis.     

转化生长因子β1/结缔组织生长因子通路在强直性脊柱炎中的表达

目的:了解强直性脊柱炎(ankylosing spondylitis,AS)骶髂关节中转化生长因子β1(transforming growthfactor beta 1,TGF-β1)/结缔组织生长因子(connective tissue growth factor,CTGF)通路的主要分子表达情况,探讨TGF-β1/CTGF通路与AS关节纤维化的关系。方法:30例AS患者均通过酶联免疫吸附(enzyme-linked immunosor-bent assay,ELISA)法检测血清TGF-β1、CTGF水平,通过免疫组织化学方法检测TGF-β1、p-smad3、smad7、CTGF、Ⅰ型胶原和Ⅲ型胶原的表达。结果:与正常对照相比,AS骶髂关节组织可见TGF-β1、CTGF高表达,主要在骨髓及血管翳中炎症细胞的胞浆中表达;smad7明显低表达,p-smad3则主要表达于骨髓及血管翳中炎症细胞的细胞核中,提示smad3已被激活;Ⅰ型胶原和Ⅲ型胶原大量沉积,但血清中的TGF-β1和CTGF的水平与正常对照组间差异无统计学意义。结论:AS骶髂关节存在TGF-β1的过高表达,smad信号通路的激活,samd7的低表达,导致CTGF高表达,Ⅰ型胶原和Ⅲ型胶原大量沉积。     

Expression of ectonucleotide pyrophosphatase-1 in end-plate chondrocytes with transforming growth factor beta 1 siRNA interference by cyclic mechanical tension

Background Ectonucleotide pyrophosphatase/phosphodiesterase （ENPP）-I is a membrane-bound protein that catalyzes the hydrolysis of extracellular nucleoside triphosphates to monophosphate and extracellular inorganic pyrophosphate （ePPi）. Mechanical stimulation regulates ENPP-1 expression. This study sought to investigate the changes in ENPP-1 expression after stimulation using cyclic mechanical tension （CMT）.     

大鼠肝纤维化中PDGF和TGF-β1的动态改变

目的　探讨肝纤维化过程中血小板衍生生长因子(PDGF)和转化生长因子 (TGF β1)表达的动态变化。方法　采用CCl4诱导的大鼠肝纤维化模型 ,分别于造模的第 3、7、10周末处死动物 ,取肝组织石蜡包埋 ,制作组织芯片 ,免疫组织化学SP法检测PDGF、TGF β1的改变。结果　正常肝组织不表达或微弱表达PDGF、TGF β1,纤维化的肝组织PDGF、TGF β1表达明显增强 ,并随肝纤维化时间的延长而增强 (P <0 0 5 ) ,第 7、10周间表达差异无显著性。两者的表达呈正相关。结论　PDGF和TGF β1是参与肝纤维化发生发展的重要生长因子     

Flagellin of Pseudomonas aeruginosa induces transforming growth factor beta 1 expression in normal bronchial epithelial cells through mitogen activated protein kinase cascades

Background  Acute lung infection due to Pseudomonas aeruginosa (P. aeruginosa) is a serious problem, especially in patients with structural lung conditions or immune compromised hosts, leading to an overwhelming threat with a high risk of morbidity and mortality. As an outcome of infection, fibrosis can be linked with chronic lung diseases. But some fibrotic manifestations, such as an irreversible decrease of lung function and fibrous bands seen on chest imaging, have been found after an acute infection with P. aeruginosa. Fibrogenesis/remodeling resulting from acute lung infection by P. aeruginosa is rarely reported. This study was designed to explore the relation between fibrogenesis/remodeling and acute infection by P. aeruginosa in vitro. We used flagellin protein from P. aeruginosa, a key initiator of acute P. aeruginosa lung infection, to elucidate mechanisms by which acute lung infection with P. aeruginosa can cause fibrogenesis/remodeling.

Methods  We studied the effect of flagellin from P. aeruginosa (flagellin for short) on the transforming growth factor beta 1 (TGF-β1) and interleukin-8 (IL-8) expression, and the possible involvement of the signaling pathway, tumor necrosis factor receptor-associated factor 6 (TRAF6)/mitogen activated protein kinase (MAPK) pathway. Flagellin was purified from the P. aeruginosa standard strain, PAO1. Normal bronchial epithelial cells BEAS-2B were challenged with different concentrations of flagellin, and cell viability assessment was performed by cell counting kit-8. BEAS-2B cells were incubated with flagellin with the specific MAPK inhibitors or TRAF6 siRNA. Cell lysates and the cultured supernatant were collected. The level of TGF-β1 and IL-8 were detected by enzyme-linked immunosorbant assay (ELISA). Western blotting was used to detect the protein levels of MAPK signal proteins p38, c-Jun NH₂-terminal kinase (JNK) and extracellular regulated kinase (ERK).

Results  Expression of TGF-β1 in BEAS-2B cells was elevated by flagellin vs. control groups ((104.3±20.8) vs. (44.6±4.4) pg/ml (P <0.01)) and was ablated by either p38 or JNK inhibitors compared with flagellin treatment ((45.1±18.8) vs. (104.3±20.8) pg/ml and (48.1±20.8) vs. (104.3±20.8) pg/ml, respectively (P <0.05)). Flagellin also elevated the expression of IL-8 in BEAS-2B cells vs. the control groups ((554.9±57.7) vs. (51.4±22.9) pg/ml (P <0.01)), and p38 MAPK inhibitors weaken the expression by flagellin ((301.1±155.1) vs. (554.9±57.7) pg/ml (P <0.05)). Western blotting revealed that all three MAPK proteins, p38, JNK and ERK were activated by flagellin challenge in an early phase, respectively in 15 minutes (P <0.01), 30 minutes (P <0.01) and 15 minutes (P <0.01). TRAF6 siRNA which decreased expression of TRAF6, altered the activation of JNK, p38, and ERK following flagellin treatment, but its influence on the expression of TGF-β1 and IL-8 has no statistical significance.

Conclusions  Flagellin from P.aeruginosa PAO1 induces TGF-β1 expression in normal bronchial epithelial cells, BEAS-2B, through the MAPK signal cascade in vitro. It suggests that the fibrogenesis/remodeling process may be initiated from an early stage of acute lung infection due to P. aeruginosa.

     

Role of interleukin-10 and transforming growth factor beta 1 in otitis media with effusion

Background Otitis media with effusion （OME） is a disease with complicated pathogeneses which are not clearly known Increasing interest has been focused on immunological cells, cytokines and their roles in chronic inflammatory states. This study was designed to disclose the existence and roles of interleukin-10 （IL-10） and transforming growth factor beta1 （TGF-β1） in the cause of OME in adults, and to investigate the probable role of Foxp3^＋CD4^＋CD25^＋ T cells in OME. Methods The concentrations of IL-10 and TGF-β1 in the middle ear effusions （MEEs） and plasmas of 36 adults （45 ears） with OME were measured by means of enzyme linked immunosorbent assay （ELISA）. As contrast, the concentrations of IL-10 and TGF-131 in the plasma of 30 normal volunteers were measured using the same method. Furthermore, the proportion of Foxp3^＋CD4^＋CD25^＋ T cells in CD4^＋ T cells of blood was tested by flow cytometry. Results （1） The concentrations of IL-10 in all MEEs and plasmas of the chronic OME patients were higher than those in patients with acute OME （both P 〈0.05）, so was TGF-131 （both P 〈0.01）. The concentration of IL-10 in MEEs was significantly higher than that in plasmas, not only in acute OME （P〈0.01）, but also in chronic OME （P〈0.01）. In chronic OME, the concentration of TGF-β1 in MEEs had no statistical difference with those in plasmas of the same patients. However, the concentration of TGF-β1 in plasmas of patients with chronic OME was significantly higher than that in plasmas of normal volunteers （P 〈0.01）. （2） The concentrations of IL-10 and TGF-β1 in MEEs of the patients who had been treated more than once were higher than those MEEs of the patients who were treated for the first time, respectively （P〈0.05, P〈0.01）. The level of TGF-β1 in plasmas of the patients who had been treated more than once was higher than in those of the patients who were treated firstly （P 〈0.05）, while the level of IL-10 in plasmas had no difference. The concentration of IL-10 in mucoid MEEs was higher than those in serous ones （P〈0.05）, while TGF-β1 had no statistical difference between mucoid and serous MEEs （P〉0.05）. The concentration of IL-10 in MEEs had a strong correlation with the duration of the illness （r=0.547, P〈0.01）. The same correlation was also found between the concentration of TGF-β1 in MEEs and the times patients being treated （r=0.579, P 〈0.01）. （3） The proportion of Foxp3^＋CD4^＋CD25^＋T/CD4^＋ T cells in the blood of chronic OME was not only significantly higher than that in the acute OME （P〈0.01）, but also higher than that in normal volunteers （P 〈0.01）. In chronic OME, there was a correlation between the proportion of Foxp3^＋CD4^＋CD25^＋ T/CD4^＋ T cells in the blood and the concentration of IL-10 in the plasmas （r=0.602, P 〈0.05）. Conclusions IL-10 and TGF-β1, as two important immunoregulatory mediators, participate in middle ear inflammatory response, especially in chronic course of OME in adults. Foxp3^＋CD4^＋CD25^＋ T cells may play some immunoregulatory roles in the course of this disease.     

乳腺癌α转化生长因子及表皮生长因子受体免疫组化双重标记研究

目的：研究α转化生长因子（TGFα）及其受体表皮生长因子受体（EGFR）在乳腺癌中的表达特点，以及两者间的相互作用。并通过与已知预后因素的相关分析，研究它们各自在肿瘤发展中的作用。方法：对84例导管浸润型乳腺癌标本进行TGFα－EGFR免疫组织化学双重标记，同时观察两者在非肿瘤及肿瘤组织的表达，并对结果进行单变量和多变量统计学分析。结果：TGFα和EGFR在癌旁组织上皮细胞中均有表达，分别在76．2％和17．8％浸润癌细胞中表达，在16．7％浸润癌细胞中同时表达。χ^2分析显示TGFα在浸润癌细胞中的表达只与ER阴性相关联，而EGFR的表达则与大体积肿瘤、炎性乳癌、腋窝淋巴结受累、不良肿瘤组织学分级（SBRⅢ级）以及雌孕激素受体阴性相关联。多变量统计分析显示，浸润癌细胞中TGFα的表达与炎性乳癌相关联（P＝0．048），而EGFR的表达则与雌激素受体阴性相关联（P＝0．002）。结论：TGFα和EGFR在乳腺癌组织中的表达与在非肿瘤组织中明显不同，并与乳腺癌不良愈后因素相关联，提示他们在乳腺癌的发展中起着重要作用。     

Smad泛素化调节因子2在转化生长因子β1诱导人肺成纤维细胞活化中的作用及其分子机制

目的:观察Smad泛素化调节因子2(Smurf2)在转化生长因子β1(TGF-β1)诱导人肺成纤维细胞活化中的作用,并探讨其可能的分子机制。方法:体外培养人胚肺成纤维细胞MRC-5,10 μg·L^-1 TGF-β1作用1、2和6 h(分别为TGF-β1 1 h组、TGF-β1 2 h组和TGF-β1 6 h组),并设对照组(不加TGF-β1), RT-PCR和Western blotting法分别检测各组细胞中Smurf1和Smurf2 mRNA和蛋白的表达水平。MRC-5细胞随机分为对照组(未加入TGF-β1或siRNA)、TGF-β1组 (10 μg·L^-1 TGF-β1)、Control siRNA转染组(10 μg·L^-1TG F-β1+Control siRNA)和Smurf2 siRNA转染组(10 μg·L^-1 TGF-β1+Smurf2 siRNA)。Western blotting法检测各组细胞中α-平滑肌肌动蛋白(α-SMA)和Ⅰ型胶原α1(COL1A1)的表达水平;RT-PCR和Western blotting法分别检测各组细胞中Smad7、核转录共抑制因子SnoN、TGF-β Ⅰ型受体(TβRⅠ)、Smad2和Smad3 mRNA和蛋白的表达水平。结果:与对照组比较,各TGF-β1组细胞中Smurf2 mRNA和蛋白表达水平均明显升高(P<0.05),且随着TGF-β1作用时间的延长,其表达水平呈逐渐增加的趋势;与对照组比较,各TGF-β1组细胞中Smurf1表达水平无明显变化(P>0.05)。与TGF-β1组比较,Smurf2 siRNA组细胞中Smurf2蛋白表达水平下降(P<0.05)。与对照组比较,TGF-β1组细胞中α-SMA和COL1A1蛋白表达水平均明显升高(P<0.05);与TGF-β1组比较,Smurf2 siRNA组细胞中α-SMA和COL1A1蛋白表达水平均下降(P<0.05)。与对照组比较,TGF-β1组和Smurf2 siRNA组细胞中Smad7和SnoN mRNA表达水平均升高(P<0.05),而Smurf2 siRNA组和TGF-β1组细胞中Smad7和SnoN mRNA表达水平无明显变化(P>0.05)。与对照组比较,TGF-β1组细胞中Smad7和SnoN蛋白表达水平均明显下降(P<0.05);与TGF-β1组比较,Smurf2 siRNA组细胞中Smad7和SnoN蛋白表达水平明显升高(P<0.05)。与对照组比较,TGF-β1组和Smurf2 siRNA组细胞中TβRⅠ mRNA和蛋白表达水平均明显升高(P<0.05),而Smurf2 siRNA组和TGF-β1组细胞中TβRⅠ mRNA和蛋白表达水平比较差异无统计学意义(P>0.05)。各组细胞中Smad2和Smad3 mRNA和蛋白表达水平比较差异无统计学意义(P>0.05)。 结论: Smurf2可能通过泛素化降解Smad7和SnoN,参与调控TGF-β1/Smads信号通路,从而发挥其促进TGF-β1活化肺成纤维细胞的作用。     

转化生长因子β1通过Smad2途径调节足细胞结缔组织生长因子表达

目的　研究肾脏足细胞是否表达结缔组织生长因子 (CTGF)以及TGFβ1对CTGF表达调控的信号途径。方法　以肾小球足细胞为对象 ,应用Western印迹分析技术 ,观察了 3种促进肾脏纤维化的蛋白因子 ,转化生长因子 β1(TGFβ1)、血小板源生长因子 (PDGF)和血管紧张素Ⅱ (AngⅡ )对体外培养的足细胞CTGF蛋白表达的影响 ,以及ERK、Smad两条信号途径在TGFβ1调节CTGF蛋白表达中的影响 ;逆转录 聚合酶链反应 (RT PCR)检测CTGFmRNA的变化。结果　体外培养的足细胞表达基础水平CTGF蛋白 ,2 0ng/mlPDGF和 10 -6mol/LAngII刺激 2 4小时后细胞内CTGF蛋白水平与对照相比差异无显著意义 (P >0 0 5 ) ,而 1ng/mlTGFβ1刺激 2 4h足细胞CTGF蛋白水平显著高于对照 (P <0 0 5 ) ,且增加呈TGFβ1剂量依赖趋势 ;1ng/mlTGFβ1刺激 12h可以使细胞CTGFmRNA表达增加。1ng/mlTGFβ1使足细胞Smad2 和细胞外信号调节激酶 (ERK1/ 2 )磷酸化 ,在刺激 30min达高峰 ;应用丝 /苏氨酸激酶抑制剂Staurosporine抑制Smad2 磷酸化可以消减TGFβ1刺激的CTGF蛋白增加 ,但ERK1/ 2 活化抑制剂PD 980 5 9阻断ERK1/ 2 磷酸化不能减弱TGFβ1刺激CTGF蛋白表达的效应。结论　在足细胞上 ,TGFβ1刺激CTGF表达依赖于Smad2 信号通路的活化 ,而不依赖于ERK1/     

转化生长因子β1(TGF-β1)诱导人肝癌细胞系的凋亡与p53及Smad4活化相关

目的:明确转化生长因子β1(TGF-β1)诱导人肝肿瘤细胞系凋亡及其与Smad的关系.方法:选用3种含有不同p53基因状态的人肝肿瘤细胞系,应用脱氧核糖核苷酸末端转移酶介导的dUTP缺口末端标记技术(TUNEL)对TGF-β1诱导的肝肿瘤细胞的凋亡进行了定量检测.为明确凋亡机制,还应用LF2000把含有Smad结合元件和荧光素酶基因的TGF-β1可诱导的荧光素酶报告质粒对细胞进行了转染,后经TGF-β1作用,分别检测其相对荧光素酶活性.结果:在应用TUNEL检测的3个细胞系中,TGF-β1仅能诱导HepG2细胞(野生型p53)凋亡,而Huh-7(突变型p53)和Hep3B细胞(缺失型p53)则凋亡较少.荧光素酶检测显示,HepG2细胞对TGF-β1反应较强,而Huh-7和Hep3B细胞其荧光素酶的表达较低.结论:HepG2细胞系比Huh-7和Hep3B细胞系更易发生TGF-β1诱导的凋亡,Smad4也许是TGF-β1信号转导途径的主要调控因子之一.     

低氧激活ERK／JNK通路促进Smad2／3蛋白磷酸化诱导小鼠心脏成纤维细胞表型转换的实验研究

目的研究体外低氧诱导小鼠心脏成纤维细胞（cardiac fibroblasts,CFs）向心脏肌成纤维细胞（cardiac myofibroblasts,CMFs）表型转换过程中,促分裂素原活化蛋白激酶（mitogen-activated protein kinases,MAPK）信号通路与Smad2／3蛋白磷酸化的关系。方法新生小鼠第1代CFs低氧（37℃、3％O2）无血清培养48h,免疫荧光检测α-SMA蛋白;新生小鼠CFs给予3种MAPK（ERK、JNK和p38）特异性抑制剂常氧培养1h,进行低氧培养30min,免疫印迹检测ERK、JNK、p38和Smad2／3蛋白磷酸化水平。结果①低氧显著上调新生小鼠CFs中α-SMA蛋白的表达;②低氧能显著地促进ERK、JNK和P38蛋白磷酸化,PD98059（ERK特异性抑制剂）、SP600125（JNK特异性抑制剂）和SB203580（P38特异性抑制剂）能抑制低氧诱导的ERK、JNK和P38蛋白的磷酸化;③PD98059（ERK特异性抑制剂）和SP600125（JNK特异性抑制剂）能抑制低氧诱导的Smad2／3蛋白的磷酸化,SB203580（P38特异性抑制剂）无此作用。结论①低氧可诱导小鼠CFs细胞发生表型转化为CMFs;②ERK和JNK信号通路能调控Smad2／3蛋白的磷酸化表达;③MAPK和Smad信号通路可能参与低氧诱导的小鼠CFs细胞的表型转化。     

转化生长因子β1(TGF-β1)诱导人肝癌细胞系的凋亡与p53及Smad4活化相关

目的:明确转化生长因子β1(TGF-β1)诱导人肝肿瘤细胞系凋亡及其与Smad的关系.方法:选用3种含有不同p53基因状态的人肝肿瘤细胞系,应用脱氧核糖核苷酸末端转移酶介导的dUTP缺口末端标记技术(TUNEL)对TGF-β1诱导的肝肿瘤细胞的凋亡进行了定量检测.为明确凋亡机制,还应用LF2000把含有Smad结合元件和荧光素酶基因的TGF-β1可诱导的荧光素酶报告质粒对细胞进行了转染,后经TGF-β1作用,分别检测其相对荧光素酶活性.结果:在应用TUNEL检测的3个细胞系中,TGF-β1仅能诱导HepG2细胞(野生型p53)凋亡,而Huh-7(突变型p53)和Hep3B细胞(缺失型p53)则凋亡较少.荧光素酶检测显示,HepG2细胞对TGF-β1反应较强,而Huh-7和Hep3B细胞其荧光素酶的表达较低.结论:HepG2细胞系比Huh-7和Hep3B细胞系更易发生TGF-β1诱导的凋亡,Smad4也许是TGF-β1信号转导途径的主要调控因子之一.     

瘦素对骨关节炎大鼠关节软骨转移生长因子β表达的影响

目的观察瘦素在外周对骨关节炎模型大鼠关节软骨中转移生长因子β表达的影响。方法将60只7周龄雄性Sprague-Dawley大鼠随机分为对照组、骨关节炎对照组(模型组)、骨关节炎实验组(观察组),每组20只,观察组大鼠膝关节中注射100μg瘦素后,取胫骨平台,用反转录-聚合酶链式反应法及免疫组织化学法检测胫骨平台关节软骨中瘦素及转移生长因子β(TGF-β)的变化。结果观察组大鼠胫骨平台关节软骨瘦素、TGF-βmRNA水平与模型组比较差异无统计学意义(P>0.05),模型组、观察组大鼠胫骨平台关节软骨瘦素、TGF-βmRNA水平均较对照组增高(P<0.05)。模型组和观察组大鼠胫骨平台关节软骨瘦素、TGF-β免疫组织化学灰度均低于对照组,差异有统计学意义(P<0.05),而模型组与观察组大鼠比较差异无统计学意义(P>0.05)。结论瘦素在外周对关节具有保护作用,在骨关节炎的病理生理过程中起重要作用。