Y-27632预处理对心肌缺血再灌注损伤过程中d凋亡的影响研究

目的：探讨Rho激酶抑制剂Y-27623对心肌缺血再灌注损伤(MIRI)中细胞凋亡的影响,以及对丝裂原活化蛋白激酶（Mitogen-activated protein kinase,MAPK）和凋亡相关蛋白表达水平的变化和意义。方法：成年雄性SD大鼠60只, 随机分为4组（n=15）:正常对照组(Sham组) 、缺血再灌注组(ischemia-reperfusion即I/R组) 、Dil组( diltiazem即地尔硫卓组)、Y-27632组。Dil组每日给予地尔硫卓(10mg/kg)灌胃, Y-27632组每日给予Y-27632（5mg/kg）,其余两组给予等体积清水。给药五天后Sham组只穿线,不结扎冠状动脉左前降支,I/R组、Dil组和Y-27632组建立MIRI模型。TUNEL法检测各组心肌凋亡,计算心肌细胞凋亡指数(AI),western blotting 法检测心肌组织中MAPK信号传导途径相关蛋白（p-JNK/ERK/P38）和凋亡相关蛋白（Bcl-2、Bax、Caspase-3和Caspase-9）的表达。结果：相对于Sham组,I/R组AI明显增加（P<0.01）,MAPK信号传导途径和心肌促凋亡相关蛋白（Bax、Caspase-3和Caspase-9）表达显著增加（均为P<0.05）,心肌抗凋亡蛋白Bcl-2表达显著减少（P<0.05）;相对于I/R组,Y-27632治疗组AI明显下降（P<0.01）,与Dil治疗组没有显著差异(P>0.05),Y-27632治疗组MAPK信号传导途径相关蛋白和Bax、Caspase-3和Caspase-9表达均显著降低（P<0.05）,Bcl-2表达显著增加（P<0.05）,与Dil治疗组没有显著差异(P>0.05)。结论：Y-27632通过抑制JNK/ERK/P38的磷酸化,抑制Bax、Caspase-3和Caspase-9的表达,加强Bcl-2的表达,来减少心肌细胞的凋亡,从而减轻心肌缺血再灌注损伤。     

Inhibitory effect of Y-27632, a ROCK inhibitor, on progression of rat liver fibrosis in association with inactivation of hepatic stellate cells.

BACKGROUND/AIMS: Activation of hepatic stellate cells (HSCs) is a final common pathway of liver fibrosis. Recently, it has been demonstrated that the small GTPase Rho is involved in HSCs activation, and that Y-27632, an inhibitor of Rho-kinase which is an effector that acts downstream of Rho, inhibits Rho-associated effects. The objective of the current study was to investigate the inhibitory effects of Y-27632 on the activation of HSCs and the progression of liver fibrosis. METHODS: Y-27632 (1, 10, 100 microM) was added to HSCs isolated from normal rat liver. RESULTS: HSCs maintained the 'star-like' configuration of the quiescent stage in the presence of Y-27632, as well as inhibition of the expression of Na+/Ca2+ exchanger mRNA which was reported to be an indicator of HSCs activation. In addition, when Y-27632 (30 mg/kg body weight) was administered to rats with carbon tetrachloride-induced liver fibrosis, collagen deposition was inhibited, the hepatic hydroxyproline content was decreased, and the serum hyaluronic acid level was reduced. Moreover, Y-27632 reduced the number of smooth muscle alpha-actin-positive cells and transforming growth factor-beta1-positive cells, and inhibited the expression of Na/Ca2+ exchanger mRNA. CONCLUSIONS: These findings indicate that Y-27632 may be useful for the clinical management of liver fibrosis.     

Connective tissue growth factor hammerhead ribozyme attenuates human hepatic stellate cell function

AIM: To determine the effect of hammerhead ribozyme targeting connective tissue growth factor (CCN2) on human hepatic stellate cell (HSC) function. METHODS: CCN2 hammerhead ribozyme cDNA plus two self-cleaving sequences were inserted into pTriEx2 to produce pTriCCN2-Rz. Each vector was individually transfected into cultured LX-2 human HSCs, which were then stimulated by addition of transforming growth factor (TGF)-b1 to the culture medium. Semiquantitative RT-PCR was used to determine mRNA levels for CCN2 or collagen Ⅰ, while protein levels of each molecule in cell lysates and conditioned medium were measured by ELISA. Cell-cycle progression of the transfected cells was assessed by flow cytometry. RESULTS: In pTriEx2-transfected LX-2 cells, TGF-β1 treatment caused an increase in the mRNA level for CCN2 or collagen Ⅰ, and an increase in produced and secreted CCN2 or extracellular collagen Ⅰ protein levels. pTriCCN2-Rz-transfected LX-2 cells showed decreased basal CCN2 or collagen mRNA levels, as well as produced and secreted CCN2 or collagen Ⅰ protein. Furthermore, the TGF-b1-induced increase in mRNA or protein for CCN2 or collagen Ⅰ was inhibited partially in pTriCCN2-Rz-transfected LX-2 cells. Inhibition of CCN2 using hammerhead ribozyme cDNA resulted in fewer of the cells transitioning into S phase. CONCLUSION: Endogenous CCN2 is a mediator of basal or TGF-b1-induced collagen Ⅰ production in human HSCs and regulates entry of the cells into Sphase.     

Connective tissue growth factor hammerhead ribozyme attenuates human hepatic stellate cell function

AIM： To determine the effect of hammerhead ribozyme targeting connective tissue growth factor （CCN2） on human hepatic stellate cell （HSC） function.
METHODS： CCN2 hammerhead ribozyme cDNA plus two self-cleaving sequences were inserted into pTriEx2 to produce pTriCCN2-Rz. Each vector was individually transfected into cultured LX-2 human HSCs, which were then stimulated by addition of transforming growth factor （TGF）-β1 to the culture medium. Semiquantitative RT-PCR was used to determine mRNA levels for CCN2 or collagen I, while protein levels of each molecule in cell /ysates and conditioned medium were measured by ELISA. Cell-cycle progression of the transfected cells was assessed by flow cytometry.
RESULTS： In pTriEx2-transfected LX-2 cells, TGF-β1 treatment caused an increase in the mRNA level for CCN2 or collagen I, and an increase in produced and secreted CCN2 or extracellular collagen I protein levels, pTriCCN2-Rz-transfected LX-2 cells showed decreased basal CCN2 or collagen mRNA levels, as well as produced and secreted CCN2 or collagen I protein. Furthermore, the TGF-β1-induced increase in mRNA or protein for CCN2 or collagen I was inhibited partially in pTriCCN2-Rz-transfected LX-2 cells. Inhibition of CCN2 using hammerhead ribozyme cDNA resulted in fewer of the cells transitioning into S phase.
CONCLUSION： Endogenous CCN2 is a mediator of basal or TGF-β1-induced collagen I production in human HSCs and regulates entry of the cells into S phase.     

Dipeptidyl peptidase-4 inhibitor attenuates hepatic fibrosis via suppression of activated hepatic stellate cell in rats

Background

Dipeptidyl peptidase-4 inhibitor (DPP4-I) is clinically used as a new oral antidiabetic agent. Although DPP4 is reportedly associated with the progression of chronic liver diseases, the effect of DPP4-I on liver fibrosis development is still obscure. This study was designed to elucidate the effect of DPP4-I on liver fibrosis development in conjunction with the activated hepatic stellate cells (Ac-HSCs).

Methods

The antifibrotic effect of DPP4-I was assessed in vivo and in vitro using porcine serum-induced experimental liver fibrosis model. DPP4-I, sitagliptin, at a clinically comparable low dose was administered by gavage daily.

Results

DPP4-I significantly attenuated liver fibrosis development along with the suppression of hepatic transforming growth factor (TGF)-β1, total collagen, and tissue inhibitor of metalloproteinases-1 in a dose-dependent manner. These suppressive effects occurred almost concurrently with the attenuation of HSCs activation. Our in vitro studies showed that DPP4-I inhibited platelet-derived growth factor-BB-mediated proliferation of the Ac-HSCs as well as upregulation of TGF-β1 and α1(I)-procollagen at magnitudes similar to those of the in vivo studies. The inhibitory effects of DPP4-I against HSCs proliferation and fibrogenic gene expression are mediated through the inhibition of the phosphorylation of ERK1/2, p38 and Smad2/3, respectively.

Conclusions

DPP4-I markedly inhibits liver fibrosis development in rats via suppression of HSCs proliferation and collagen synthesis. These suppressive effects are associated with dephosphorylation of ERK1/2, p38 and Smad2/3 in the HSCs. Since DPP4-I is widely used in clinical practice, this drug may represent a potential new therapeutic strategy against liver fibrosis in the near future.     

A rho kinase inhibitor, Y-27632 inhibits pulmonary eosinophilia, bronchoconstriction and airways hyperresponsiveness in allergic mice

Asthma is a complex inflammatory disorder involving obstruction, constriction, oedema, remodelling and hyperresponsiveness of the airways. These effects are induced by a raft of mediators, many of which exert their actions by stimulating specific G-protein-coupled receptors linked to a signal transduction pathway involving the monomeric GTPase; rho, and a downstream effector; rho kinase. The aim of this study was to determine whether administration of a selective inhibitor of rho kinase, Y-27632, attenuates airway inflammation, bronchoconstriction and hyperresponsiveness in a murine model of acute allergic inflammation. Intranasal administration of Y-27632 caused a dose-dependent inhibition in the number of eosinophils recovered from bronchoalveolar lavage fluid of ovalbumin-sensitised and challenged (allergic) mice. These inhibitory effects of intranasal Y-27632 on pulmonary eosinophilia were accompanied by a significant inhibition of the development of airways hyperresponsiveness in allergic mice. In additional studies, intranasal Y-27632 inhibited methacholine-induced increases in airways resistance in a time-dependent manner. In conclusion, these findings indicate that activation of rho kinase contributes to bronchoconstriction and eosinophil trafficking in murine models of acute allergic airway inflammation and to the development of airway hyperresponsiveness.     

A selective ROCK inhibitor, Y27632, prevents dimethylnitrosamine-induced hepatic fibrosis in rats

BACKGROUND: p160ROCK is a direct Rho target which mediates Rho-induced assembly of focal adhesions and stress fibers. We previously reported that Rho signaling pathways are involved in the activation of hepatic stellate cells (HSC) in vitro. The aim of the present study was to test the hypothesis that an inhibitor specific for p160ROCK (Y27632) could prevent experimental hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats. METHODS: Y27632 was given orally at 30 mg/kg daily for 4 weeks after the first injection of DMN. The degree of fibrosis was evaluated by image analysis and also by measurements of collagen and hydroxyproline content in the liver. The expression of alpha-smooth muscle actin (alpha-SMA) in the liver and in the primary cultured HSC was also evaluated. Semi-quantitative RT-PCR was performed to evaluate the expression of type I collagen mRNA in the liver. RESULTS: Y27632 treatment significantly decreased the occurrence of DMN-induced hepatic fibrosis and reduced the collagen and hydroxyproline content and alpha-SMA expression in the liver. The expression of alpha-SMA in HSC was also suppressed in vitro. CONCLUSIONS: These findings indicate that inhibitors of the Rho-ROCK pathway might be useful therapeutically in hepatic fibrosis.     

Raf kinase inhibitor protein inhibits cell proliferation but promotes cell migration in rat hepatic stellate cells

Aim: Hepatic stellate cells (HSCs) play an important role in the pathogenesis of liver fibrosis and cirrhosis. Raf kinase inhibitor protein (RKIP), an inhibitor of extracellular signal‐regulated kinases (ERK)/mitogen‐activated protein kinase (MAPK) signalling pathway, has been proved to suppress tumor metastasis. Interestingly, RKIP promotes cell migration in Madin–Darby canine kidney epithelial cells. However, the effects of RKIP on HSC behaviours are unknown. The purpose of the present study is to investigate the role of RKIP in HSC proliferation, apoptosis and migration. Methods: Two types of cells, freshly isolated HSC and HSC‐T6 cell line, were used in this study. The amount of RKIP, the phosphorylation of RKIP, Raf and ERK (pRKIP, pRaf and pERK) were analysed in quiescent and activated HSCs by Western blots. HSC‐T6 cells were transfected with RKIP‐expressing plasmid or treated with locostatin, a RKIP inhibitor. HSC proliferation, apoptosis and migration were evaluated with 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay, terminal deoxynucleotidyl transferase‐mediated deoxyuridine triphosphate nick‐end labelling (TUNEL) staining and Transwell cell migration assay respectively. Results: In activated HSCs, RKIP protein expression was downregulated whereas pRKIP, pRaf and pERK were upregulated. RKIP overexpression significantly mitigated the phosphorylation of RKIP, Raf and ERK. This in turn inhibited HSC proliferation. Locostatin not only inhibited RKIP protein expression but also, to some extent, reversed the RKIP‐inhibited phosphorylation of RKIP, Raf and ERK. RKIP augmented HSC migration and enhanced wound closure. Locostatin reversed the effects of RKIP. Conclusion: Raf kinase inhibitor protein inhibits ERK/MAPK signalling and this inhibition impedes HSC proliferation. RKIP promotes HSC migration and wound closure.     

Rho激酶抑制剂Y-27632对人气道平滑肌细胞增殖和细胞周期的影响

目的观察Rho激酶抑制剂Y-27632对人气道平滑肌细胞（ASMCs）增殖的影响,为哮喘防治提供新思路。方法组织块贴壁法培养人ASMCs,对数传代后随机分为4组,A组加入含10％FBS的DMEM培养基,B、C、D组分别加入浓度为0．4、2．0、10．0μmol／L的Y-27632＋含10％FBS的DMEM培养基,非放射性细胞增殖（MTS）／吩嗪甲酯硫酸盐（PMS）法检测各组细胞增殖情况（490nm处A值）,流式细胞仪分析细胞周期。结果C、D组A值均显著低于A组（P〈0．05、0．01）;C、D组G0／G1期细胞比例显著高于A组,S、G2／M期细胞比例显著低于A组（P〈0．05、0．01）。结论Rho激酶抑制剂Y-27632可抑制人ASMCs增殖,阻滞细胞周期于G0／G1期;本研究为哮喘防治提供了新的选择。     

Oxymatrine liposome attenuates hepatic fibrosis via targeting hepatic stellate cells

AIM: To investigate the potential mechanism of Arg-Gly-Asp (RGD) peptide-labeled liposome loading oxymatrine (OM) therapy in CCl₄-induced hepatic fibrosis in rats.METHODS: We constructed a rat model of CCl₄-induced hepatic fibrosis and treated the rats with different formulations of OM. To evaluate the antifibrotic effect of OM, we detected levels of alkaline phosphatase, hepatic histopathology (hematoxylin and eosin stain and Masson staining) and fibrosis-related gene expression of matrix metallopeptidase (MMP)-2, tissue inhibitor of metalloproteinase (TIMP)-1 as well as type I procollagen via quantitative real-time polymerase chain reaction. To detect cell viability and apoptosis of hepatic stellate cells (HSCs), we performed 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-diphenytetrazoliumromide assay and flow cytometry. To reinforce the combination of oxymatrine with HSCs, we constructed fluorescein-isothiocyanate-conjugated Arg-Gly-Asp peptide-labeled liposomes loading OM, and its targeting of HSCs was examined by fluorescent microscopy.RESULTS: OM attenuated CCl₄-induced hepatic fibrosis, as defined by reducing serum alkaline phosphatase (344.47 ± 27.52 U/L vs 550.69 ± 43.78 U/L, P < 0.05), attenuating liver injury and improving collagen deposits (2.36% ± 0.09% vs 7.70% ± 0.60%, P < 0.05) and downregulating fibrosis-related gene expression, that is, MMP-2, TIMP-1 and type I procollagen (P < 0.05). OM inhibited cell viability and induced apoptosis of HSCs in vitro. RGD promoted OM targeting of HSCs and enhanced the therapeutic effect of OM in terms of serum alkaline phosphatase (272.51 ± 19.55 U/L vs 344.47 ± 27.52 U/L, P < 0.05), liver injury, collagen deposits (0.26% ± 0.09% vs 2.36% ± 0.09%, P < 0.05) and downregulating fibrosis-related gene expression, that is, MMP-2, TIMP-1 and type I procollagen (P < 0.05). Moreover, in vitro assay demonstrated that RGD enhanced the effect of OM on HSC viability and apoptosis.CONCLUSION: OM attenuated hepatic fibrosis by inhibiting viability and inducing apoptosis of HSCs. The RGD-labeled formulation enhanced the targeting efficiency for HSCs and the therapeutic effect.     

大鼠肝纤维化自发逆转过程中肝星状细胞凋亡与p75的表达

肝星状细胞（HSC）凋亡是肝纤维化逆转的主要机制之一。人和大鼠的HSC表达低亲和力神经生长因子受体p75，当p75与神经生长因子（NGF）结合时可引起细胞凋亡。本研究通过建立四氯化碳（CCl4）肝纤维化大鼠模型，对肝纤维化自发逆转过程中HSC凋亡和p75表达进行了研究。     

硫化氢在p38MAPK信号通路对大鼠肝星状细胞凋亡中的作用

目的探讨硫化氢(H2S)在p38MAPK信号通路对大鼠肝星状细胞(hepatic stellate cell,HSC)凋亡中的作用及磷酸化P38、Caspase-3蛋白表达的变化。方法实验设对照组(HSC加含10%胎牛血清的DMEM培养液)、二甲基亚砜(DMSO)组(对照组基础上加DMSO,使其终浓度为0.1%)、NaHS组(对照组基础上加NaHS,使其终浓度为50μmol/L)、SB组(DMSO组基础上加SB203580,使其终浓度为75μmol/L)、SB加NaHS(SB+NaHS)组;采用Hoechst荧光染色检测细胞凋亡;Western blotting法检测磷酸化p38MAPK表达及Caspase-3蛋白表达水平。结果与对照组比较,SB组和SB+NaHS组HSC-T6的凋亡率增加(P0.05),NaHS组p38MAPK磷酸化水平及Caspase-3表达均明显增高(P0.01);与NaHS组比较,SB组和SB+NaHS组细胞凋亡率增加明显(P0.01),p38MAPK磷酸化水平表达降低(P0.01);SB+NaHS组较SB组Caspase-3蛋白表达升高(P0.05)。结论 p38MAPK及Caspase-3在H2S刺激的HSC-T6中表达增强,H2S能促使SB203580诱导的HSC-T6细胞凋亡,其作用机制可能与活化p38MAPK的磷酸化途径,进而激活Caspase-3的表达有关。     

奥曲肽对肝星状细胞收缩的影响

目的:探讨奥曲肽(OCT)对内皮素-1(ET-1)刺激的肝星状细胞(HSC)收缩的影响,以及此过程中胞质游离钙([Ca2 ]i)的变化.方法:应用体外HSC培养技术,借助激光共聚焦显微镜(LSCM),采用第三代钙荧光探针Fluo-3/AM观察OCT、ET-1介导的HSC[Ca2 ]i荧光强度、细胞面积及最大长径的变化.结果:2.5mg/LOCT对HSC内Ca2 浓度及收缩无显著影响;5.0mg/L、10.0mg/L组OCT能够即刻引起HSC内Ca2 浓度显著下降,10min时下降率分别为36.59%、39.13%(P<0.05),但对HSC收缩无显著影响.ET-1引起HSC内Ca2 浓度短暂而明显的升高以及HSC显著的收缩.5.0mg/L、10.0mg/L组OCT能够抑制ET-1引起的HSC内Ca2 浓度升高及收缩作用(P<0.05).结论:OCT可即刻引起HSC内Ca2 浓度下降,但对HSC收缩影响不大.OCT能够抑制ET-1引起的HSC收缩.     

蛋白酶体抑制剂诱导肝星状细胞凋亡的研究进展

泛素-蛋白酶体通路（ubiquitin proteasome pathway，UPP）是一种高效蛋白降解途径，主要负责真核细胞内蛋白质的选择性降解。其中，蛋白酶体是一种广泛存在的酶复合体，它参与细胞周期调控、凋亡、血管发生过程中多种蛋白质的降解等过程，从而在细胞存活、纤维化、肿瘤发生发展过程中起着重要作用。目前包括硼替佐米（bortezomib）在内的多种蛋白酶体抑制剂已经开始应用于临床多种恶性肿瘤的治疗，在肝纤维化方面的研究也开始进入萌芽阶段，现就近年来其与HSC凋亡关系的研究进展作一综述。[第一段]     

抗纤软肝颗粒对大鼠肝星状细胞增殖的影响

目的:探讨抗纤软肝颗粒(KXRG)对大鼠肝星状细胞(HSC)增殖的影响。方法:传代培养的HSC-T6(肝星状细胞系)与KXRG(1.25mg/ml、2.5mg/ml、5mg/ml)及其药物血清(5%、10%、20%)共同培养72小时后,应用MTT法测定细胞增殖、流式细胞仪测定HSC细胞周期各时相的DNA含量。结果:KXRG及药物血清均能显著抑制HSC的增殖,使细胞周期阻滞于S期,且2.5mg/ml药物和10%药物血清作用最强(P0.01)。结论:KXRG通过抑制HSC的活化,阻滞其细胞周期的正常进行,进而抑制HSC增殖,从而起到抗肝纤维化的作用。     

抗血管生成药苏拉明对大鼠肝星状细胞的影响

目的 探讨抗血管生成药苏拉明(Suramin)对体外培养肝星状细胞(HSC)的影响及其抗纤维化的作用.方法 将大鼠HSC-T6体外培养,用MTT法初测细胞增殖趋势、流式细胞仪定性及定量检测HSC的细胞周期和增殖指数;免疫组织化学检测α-平滑肌肌动蛋白(α-SMA);ELISA法测定细胞上清液中Ⅲ型胶原含量.结果 与对照组相比,不同浓度Suramin组的HSC增殖均受抑制,阻抑在细胞周期G1期,呈时间和剂量依赖性(P＜0.05).各浓度组α-SMA灰度值亦低于对照组(P＜0.05).不同浓度Suramin组的上清液中Ⅲ型胶原均低于对照组,TGF-β1,+Suramin组的含量介于TGF-β1组和Suramin组之间.结论 抗血管生成药Suramin抑制HSC增殖和活化,从而减轻Ⅲ型胶原沉积,起到抗肝纤维化作用,即Suramin在临床应用上有多靶点抗肝纤维化的优势,但其具体机制有待进一步研究.     

The tumor suppressor protein PTEN inhibits rat hepatic stellate cell activation

Background  Following a fibrogenic stimulus, the hepatic stellate cell (HSC) transforms from a quiescent to an activated cell type associated with increased proliferation, collagen and smooth muscle α-actin (αSMA) expression. Phosphatase and Tensin Homolog Deleted on Chromosome Ten (PTEN), a tumor suppressor phosphatase, has been shown to play a role in several nonmalignant diseases. Here, we investigated the role of PTEN during HSC activation. Methods  Rat HSCs 2 days after isolation were transduced with adenoviruses expressing either the wild-type (WT) or a dominant negative form of PTEN, and culture-associated activation of HSCs, including morphological changes, expression of αSMA and α1(I) collagen, and cell proliferation, were evaluated. Apoptosis of HSCs was detected by measuring activity of caspase 3/7. Phosphorylation status of Akt, p70^S6K, and Erk was detected by Western blotting. Results  Overexpression of WT-PTEN inhibited phenotypic changes were associated with HSC activation, including morphological changes, expression of αSMA and α1(I) collagen, and HSC proliferation, including cyclin D1 expression. WT-PTEN expression also induced apoptosis in HSCs with increased caspase 3/7 activity. Expression of WT-PTEN also caused decreased activation of Akt, p70^S6K, and Erk signaling pathways. Conclusions  Taken together, these findings show that PTEN represents an important negative regulator for transactivation of HSCs. This may have important implications for the design of therapeutic strategies to prevent the progression of liver fibrosis.