肝星状细胞SSeCKS的表达及其在肝纤维化中的作用

目的 了解src抑制的蛋白激酶C底物(SSeCKS)在肝星状细胞(HSC)活化中的变化和作用.方法 (1)分离正常大鼠的HSC,以实时定量PCR检测其在体外培养过程中SSeCKS mRNA的表达变化,以蛋白质印迹法和细胞免疫荧光法检测HSC中SSeCKS蛋白的表达变化.(2)制作肝纤维化的大鼠模型,以免疫荧光法检测肝组织内SSeCKS和α-平滑肌肌动蛋白(α-SMA)的表达变化及定位.结果 初分离的HSC表达低水平的SSeCKS mRNA,经培养活化后SSeCKS的表达增强.在纤维化肝组织中,SSeCKS阳性细胞增多,阳性细胞多分布于肝窦周围,与α-SMA阳性细胞的分布一致.结论 在体外活化过程中HSC中SSeCKS表达增强.SSeCKS可能参与HSC在肝脏炎症和纤维化中的作用.     

Extracellular matrix degradation and the role of hepatic stellate cells

Following liver injury, hepatic stellate cells (HSCs) become activated and express a combination of matrix metalloproteinases (MMPs) and their specific tissue inhibitors (TIMPs). In the early phases of liver injury (and primary cell culture), HSCs transiently express MMP-3, MMP-13, and uroplasminogen activator (uPA) and exhibit a matrix-degrading phenotype. In the later stages of liver injury and HSC activation, the pattern changes and the cells express a combination of MMPs that have the ability to degrade normal liver matrix, while inhibiting degradation of the fibrillar collagens that accumulate in liver fibrosis. This pattern is characterized by the combination of pro-MMP-2 and membrane type 1 (MT1)-MMP expression, which drive pericellular generation of active MMP-2 and local degradation of normal liver matrix. In addition there is a marked increase in expression of TIMP-1 leading to a more global inhibition of degradation of fibrillar liver collagens by interstitial collagenases (MMP-1/MMP-13). These pathways play a significant role in the progression of liver fibrosis. Following cessation of liver injury, the pattern reverses and TIMP-1 in particular is rapidly downregulated. This phase is characterized by increasing activity of collagenases, degradation of liver matrix, and regression of liver fibrosis.     

Signal transduction in hepatic stellate cells

ABSTRACT— Hepatic stellate cells (HSC) are presently regarded as one of the key cell types involved in the progression of liver fibrosis and in the related pathophysiological and clinical complications. Following acute or chronic liver tissue damage, HSC undergo a process of activation towards a phenotype characterised by increased proliferation, motility, contractility and synthesis of extracellular matrix (ECM) components. Several factors have been shown to play a key role in the promotion of the full-blown picture of activated HSC. These include extensive changes in the composition and organisation of the ECM, the secretion of several growth factors, cytokines, chemokines, products of oxidative stress and other soluble factors. It is evident that each cellular response to extracellular stimuli must be framed in a scenario where different forces modulate one another and result in a prevalent biological effect. Along these lines, the identification and characterisation of intracellular signalling pathways activated by different stimuli in HSC represent a mandatory step. In this review article we have made an attempt to summarise recent acquisitions to our knowledge of the involvement of different intracellular signalling pathways in key aspects of HSC biology.     

肝星状细胞在肝细胞癌形成和发展中的作用

肿瘤的发生、侵袭及转移是长久以来备受关注的问题,肿瘤细胞与其周围基质物质的关系作为其中的关键因素愈加收到重视,肝星状细胞(HSC)作为肝癌微环境中的重要组成部分,在"炎症-肝纤维化/肝硬化-肿瘤"这一发生发展过程中充当了重要的介质。介绍了HSC的来源及其活化过程,并进一步阐述HSC自身与其分泌的多种细胞因子在肝细胞癌增殖、迁移、侵袭过程中对机体免疫反应发挥的作用。认为HSC不仅是肿瘤生长的"温床",也为肿瘤抵御了免疫系统的追踪和清除。因此在单一抗肿瘤治疗无法取得明显效果时,对于肝癌微环境的多方位治疗成为值得探讨的方案。     

Curcumin downregulates Smad pathways and reduces hepatic stellate cells activation in experimental fibrosis

Introduction and ObjectivesCurcumin, a polyphenol, is a natural compound that has been widely studied as a hepatoprotector; however, only a few studies have examined its ability to reduce fibrosis in previously established cirrhosis. The objective of this study was to investigate whether curcumin could reduce carbon tetrachloride (CCl₄)-induced fibrosis and if so, to determine the action mechanisms involved in the reduction process.Materials and MethodsCCl₄ was administered to male Wistar rats (400 mg/kg, three times a week, i. p.) for 12 weeks; curcumin (100 mg/kg body weight twice per day, p. o.) was administered from week 9–12 of CCl₄ treatment. Biochemical markers of hepatic injury and oxidative stress were evaluated. Hematoxylin and eosin, Masson’s trichrome stains, transmission electron microscopy; immunohistochemistry, and zymography assays were carried out. Moreover, Smad3 and α-SMA mRNA and protein levels were studied. Western blotting by TGF-β, CTGF, Col-I, MMP-13, NF-κB, IL-1, IL-10, Smad7, pSmad3, and pJNK proteins was developed.Results and ConclusionsCurcumin reduced liver damage, oxidative stress, fibrosis, and restored normal activity of MMP-9 and MMP-2. Besides, curcumin restored NF-κB, IL-1, IL-10, TGF-β, CTGF, Col-I, MMP-13, and Smad7 protein levels. On the other hand, curcumin decreased JNK and Smad3 phosphorylation. Furthermore, curcumin treatment decreased α-SMA and Smad3 protein and mRNA levels. Curcumin normalized GSH, and NF-κB, JNK-Smad3, and TGF-β-Smad3 pathways, leading to a decrement in activated hepatic stellate cells, thereby producing its antifibrotic effects.     

转化生长因子β1活化肝星状细胞反式激活新基因剪切体的功能

目的 探讨反式激活新基因剪切体TTG 1 A的生物学功能和参与肝纤维化的致病机制.方法 应用酵母双杂交系统3,将PCR扩增的TTG1A基因与酵母表达载体pGBKT7连接,转化酵母细胞AH109,并在其内表达,而后与转化了人白细胞文库的质粒pACT2的单倍体酵母细胞Y187进行配合,在涂有X-α-gal营养缺陷型培养基上进行双重筛选,提取阳性酵母克隆的质粒转化大肠杆菌经Bgl Ⅱ酶切后测序,进行生物信息学分析. 结果成功构建了重组酵母表达载体pGBKT7-TTGlA.应用酵母双杂交系统3从人白细胞文库中筛选出19个与TTGlA相互作用的蛋白,其中包括人类主要组织相容性复合物Ⅱ型DP D(HLA-DP β),人类核糖体蛋白L30、人类核磷蛋白B23、人类核组蛋白2、人类ash2、人类变异的家族性睥性贫血和变异的异染性脑白质营养不良相关蛋白,人类死亡因子4(MORF4L1)、人类遍在蛋白偶连酶E2L3、人类载脂蛋白A-1(APOA1)、人类半乳凝素1以及5个未知功能蛋白. 结论 成功构建了重组酵母表达载体pGBKT7-TTGlA,初步揭示了新基因TTGlA的生物学功能,为进一步研究TGF β1介导的肝纤维化分子发病机制中的作用提供基础.     

活化肝星状细胞的信号传导

肝纤维化是肝脏对各种急慢性肝损伤的疤痕修复反应的结果,是各种慢性肝病向肝硬化进展的共同环节,其最主要的特征是以胶原为主的细胞外基质(ECM)的生成与降解失衡,在肝脏中的过度沉积.活化的肝星状细胞(HSC)是肝纤维化发生时ECM的主要来源.HSC持续激活后增殖、迁移和表型转化,成为肌成纤维样细胞,是肝纤维化发生和发展的核心环节.活化HSC具有如下特点:(1)合成和分泌间质胶原等各种ECM;(2)自分泌产生致纤维化细胞因子如转化生长因子(TGF)β I;(3)释放胶原酶抑制物组织金属蛋白酶抑制剂(TIMP);(4)分泌趋化因子及其他炎症性细胞因子;(5)具有细胞收缩特性;(6)合成基质金属蛋白酶(MMP),使ECM降解异常;(7)对凋亡刺激的耐受性等.     

贮脂细胞内的信号传导分子

近年来对贮脂细胞(hepatic stellate cell,HSC)的激活过程已有了广泛的研究,特别是对HSC活化中的级联变化,包括形态上的显著变化,细胞外基质(extracellular matrix,ECM)合成,生长因子和细胞因子受体表达,收缩结构和金属蛋白酶上调等方面的研究,现对这些基因的调节和相应细胞内信号传导机制综述如下。     

Rho蛋白与肝星状细胞

小G蛋白Rho家族是一类能结合GTP的蛋白质, 在细胞信号传导通路中发挥着"分子开关"的作用, 能通过下游蛋白产生多种生物学效应.肌动蛋白细胞骨架是维持细胞形态, 介导真核细胞必需的生物学功能的重要结构, 参与细胞收缩、迁移和生存等多个过程.肝星状细胞(hepatic stellate cells, HSCs)是肝纤维化形成过程和调节门脉血流的关键细胞, 其肌动蛋白细胞骨架的变化反映了HSCs的活化状态.故本文重点介绍Rho家族在对HSCs的肌动蛋白细胞骨架重构、细胞收缩、迁移及生存方面的调控机制, 进而探讨对Rho家族及其信号途径的调控是否能成为抗门脉高压和肝纤维化治疗的新靶点.     

干扰素α对实验大鼠肝内纤维组织及肝星状细胞的影响

目的 探讨干扰素(IFN)α防治肝纤维化作用机制。方法 雄性SD大鼠54只分成A组(正常对照组)6只、B组(模型对照组)12只、C组(IFNα预防组)12只、D组(IFNα治疗组)12只和E组(生理盐水对照组)12只。分别于实验6～12周末处死,取肝组织行病理组织学与电镜下同步观察。结果 B组大鼠肝内纤维组织广泛增生,假小叶形成,活化的肝星状细胞(HSC)明显增多,C组和D组肝内纤维组织明显减轻,活化HSC数量减少,凋亡数目明显增多。结论 IFNα通过抑制HSC活化并诱导其凋亡防治肝纤维化形成。     

整合素与肝星状细胞活化

整合素(integrin)参与细胞和细胞外基质(ECM)、细胞和细胞间的黏附,介导与细胞活化、增殖、运动和凋亡等有关的信号,在免疫调节、肿瘤浸润、损伤修复中起重要作用。慢性肝损伤中静止的肝星状细胞(HSC)活化、增殖、表型转变,ECM异常沉积,星状细胞整合素表达水平和受体亲和力改变,并与生长因子协同作用参与肝纤维化的分子机制。一、整合素家族(一)整合素分子结构整合素(或整合素受体)是由α、β两个亚基非共价结合成的异源二聚体细胞表面糖蛋白。目前已发现8种类型的β亚基和18种α亚基,装配成至少24种不同的亚型受体,分布有选择性和时序…