Involvement of 90-kuD ribosomal S6 kinase in collagen type Ⅰ expression in rat hepatic fibrosis

AIM: To investigate the relationship between 90-kuD ribosomal S6 kinase (p90RSK) and collagen type Ⅰ expression during the development of hepatic fibrosis in vivo and in vitro. METHODS: Rat hepatic fibrosis was induced by intraperitoneal injection of dimethylnitrosamine. The protein expression and cell location of p90RSK and their relationship with collagen type Ⅰ were determined by co-immunofluoresence and confocal microscopy. Subsequently, RNAi strategy was employed to silence p90RSK mRNA expression in HSC-T6, an activated hepatic stellate cell (HSC) line. The expression of collagen type Ⅰ in HSC-T6 cells was assessed by Western blotting and real-time polymerase chain reaction. Furthermore, HSCs were transfected with expression vectors or RNAi constructs of p90RSK to increase or decrease the p90RSK expression, then collagen type Ⅰ promoter activity in the transfected HSCs was examined by reporter assay. Lastly HSC-T6 cells transfected with p90RSK siRNA was treated with or without platelet-derived growth factor (PDGF)-BB at a final concentration of 20 μg/L and the cell growth was determined by MTS conversion. RESULTS: In fibrotic liver tissues, p90RSK was overexpressed in activated HSCs and had a significant positive correlation with collagen type Ⅰ levels. In HSC-T6 cells transfected with RNAi targeted to p90RSK, the expression of collagen type Ⅰ was downregulated (61.8% in mRNA, P < 0.01, 89.1% in protein, P < 0.01). However, collagen type Ⅰ promoter activity was not increased with over-expression of p90RSK and not decreased with low expression either, compared with controls in the same cell line ( P = 0.076). Furthermore, p90RSK siRNA exerted the inhibition of HSC proliferation, and also abolished the effect of PDGF on the HSC proliferation. CONCLUSION: p90RSK is over-expressed in activated HSCs and involved in regulating the abnormal expression of collagen type Ⅰ through initiating the proliferation of HSCs.     

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.     

Notch3 regulates the activation of hepatic stellate cells

AIM: To investigate whether Notch signaling is involved in liver fibrosis by regulating the activation of hepatic stellate cells (HSCs).METHODS: Immunohistochemistry was used to detect the expression of Notch3 in fibrotic liver tissues of patients with chronic active hepatitis. The expression of Notch3 in HSC-T6 cells treated or not with transforming growth factor (TGF)-β1 was analyzed by immunofluorescence staining. The expression of Notch3 and myofibroblastic marker α-smooth muscle actin (α-SMA) and collagen I in HSC-T6 cells transfected with pcDNA3.1-N3ICD or control vector were detected by Western blotting and immunofluorescence staining. Moreover, effects of Notch3 knockdown in HSC-T6 by Notch3 siRNA were investigated by Western blotting and immunofluorescence staining.RESULTS: The expression of Notch3 was significantly up-regulated in fibrotic liver tissues of patients with chronic active hepatitis, but not detected in normal liver tissues. Active Notch signaling was found in HSC-T6 cells. TGF-β1 treatment led to up-regulation of Notch3 expression in HSC-T6 cells, and over-expression of Notch3 increased the expression of α-SMA and collagen I in HSC-T6 without TGF-β1 treatment. Interestingly, transient knockdown of Notch3 decreased the expression of myofibroblastic marker and antagonized TGF-β1-induced expression of α-SMA and collagen I in HSC-T6.CONCLUSION: Notch3 may regulate the activation of HSCs, and the selective interruption of Notch3 may provide an anti-fibrotic strategy in hepatic fibrosis.     

Hepatocyte nuclear factor 4α induces a tendency of differentiation and activation of rat hepatic stellate cells

AIM: To investigate the effect of hepatocyte nuclear factor 4α(HNF4α) on the differentiation and transformation of hepatic stellate cells(HSCs).METHODS: By constructing the recombinant adenovirus vector expressing HNF4α and HNF4αshRNA vector, and manipulating HNF4α expression in HSC-T6 cells, we explored the influence of HNF4α and its induction capacity in the differentiation of rat HSCs into hepatocytes.RESULTS: With increased expression of HNF4αmediated by AdHNF4α, the relative expression of Nanog was downregulated in HSC-T6 cells(98.33 ±12.33 vs 41.33 ± 5.67, P 0.001). Consequently, the expression of G-P-6 and PEPCK was upregulated(G-P-6:14.34 ± 3.33 vs 42.53 ± 5.87, P 0.01; PEPCK: 10.10± 4.67 vs 56.56 ± 5.25, P 0.001), the expression of AFP and ALB was positive, and the expression of Nanog, Type Ⅰ collagen, α-SMA, and TIMP-1 was significantly decreased. HNF4α also downregulated vimentin expression and enhanced E-cadherin expression. The ultrastructure of HNF4α-induced cells had more mitochondria and ribosomes compared with the parental cells. After silencing HNF4α expression,EPCK, E-cadherin, AFP, and ALB were downregulated and α-SMA and vimentin were upregulated.CONCLUSION: HNF4α can induce a tendency of differentiation of HSCs into hepatocyte-like cells. These findings may provide an effective way for the treatmentof liver diseases.     

Glycyrrhizic acid inhibits apoptosis and fibrosis in carbontetrachloride-induced rat liver injury

AIM:To investigate anti-apoptotic effects of glycyrrhizic acid(GA) against fibrosis in carbon tetrachloride(CCl4)-induced liver injury and its contributing factors.METHODS:Liver fibrosis was induced by administration of CCl4 for 8 wk.Pathological changes in the liver of rats were examined by hematoxylin-eosin staining.Collagen fibers were detected by Sirius red staining.Hepatocyte apoptosis was determined by TUNEL assay and the expression levels of cleaved caspase-3,Bax,α-SMA,connective tissue growth factor(CTGF),matrix metalloproteinase(MMP) 2 and MMP9 proteins were evaluated by western blot analysis,and α-SMA m RNA,collagen type Ⅰ and Ⅲ m RNA were estimated by real-time PCR.RESULTS:Treatment with GA significantly improved the pathological changes in the liver and markedly decreased the positive area of Sirius red compared with rats in the CCl4-treated group.TUNEL assay showed that GA significantly reduced the number of TUNEL-positive cells compared with the CCl4-treated group.The expression levels of cleaved caspase-3,Bax,α-SMA,CTGF,MMP2 and MMP9 proteins,and α-SMA m RNA,collagen type Ⅰ and Ⅲ m RNA were also significantly reduced by GA compared with the CCl4-treated group(P 0.05).CONCLUSION:GA treatment can ameliorate CCl4-induced liver fibrosis by inhibiting hepatocyte apoptosis and hepatic stellate cell activation.     

Targeting collagen expression in alcoholic liver disease

Alcoholic liver disease(ALD)is a leading cause of liver disease and liver-related deaths globally,particularly in developed nations.Liver fibrosis is a consequence of ALD and other chronic liver insults,which can progress to cirrhosis and hepatocellular carcinoma if left un-treated.Liver fibrosis is characterized by accumulation of excess extracellular matrix components,including typeⅠcollagen,which disrupts liver microcirculation and leads to injury.To date,there is no therapy for the treatment of liver fi...     

siRNA沉默β-Catenin对肝星状细胞增殖和凋亡的影响

目的研究siRNA干扰β-Catenin表达,阻断Wnt/β-Catenin信号通路对肝星状细胞（HSC）增殖和凋亡的影响。方法将化学合成的siRNAβ-Catenin以Lipofectamine包裹,转染HSC-T6细胞,设阴性对照和空白对照;采用逆转录-聚合酶链反应和Western blotting检测细胞β-Catenin表达;采用Western blotting法检测细胞Ⅰ、Ⅲ型胶原表达;采用MTT法和流式细胞仪检测细胞增殖和细胞凋亡。结果以不同浓度的β-Catenin SiRNA转染HSC-T6细胞后,β-Catenin mRNA水平比阴性对照组分别下调了51.3±3.6%、85.7±6.8%和94.5±7.5%（P均〈0.01）,比空白对照组分别下调了50.5±3.4%、86.1±6.2%和93.7±7.2%（P均〈0.01）;β-Catenin蛋白表达被抑制了56.43±2.88%（P〈0.01）;Ⅰ和Ⅲ型胶原表达分别被抑制了46.58±3.46%（P〈0.01）和50.48±3.72%（P〈0.01）;细胞增殖明显被抑制,最大抑制率达到44.8±2.8%（P〈0.01）;细胞凋亡增加达28.6%（P〈0.05）。结论 siRNAβ-Catenin能高效抑制HSC-T6细胞β-Catenin表达,阻断Wnt/β-Catenin信号通路,从而抑制HSC-T6细胞增殖,促进凋亡,显著减少Ⅰ、Ⅲ型胶原的合成和分泌,具有预防及治疗肝纤维化的潜力。     

抗血小板衍生生长因子受体的核酶对肝星状细胞生物学特性的影响

目的 研究抗血小板衍生生长因子受体β亚单位(PDGFR-β)核酶在肝星状细胞(HSC)内的切割活性及其对HSC生物学特性的影响。 方法 构建抗PDGFR-β核酶的真核表达载体,将其转染入HSC-T6细胞,G418筛选出阳性细胞克隆;分别用northern blot、western blot和免疫细胞化学检测PDGFR-β表达,用MTT法检测细胞增殖,免疫细胞化学检测α-F滑肌肌动蛋白(α-sMA)和Ⅰ、Ⅲ型胶原表达,用流式细胞仪、吖啶噔荧光染色和电镜分析细胞凋亡。 结果 转染核酶的HSC的PDGFR-β在mRNA和蛋白水平的表达量均显著降低,仅为对照组的43％～51％(t≥3.95 7,P<0.05);增殖活性显著低于对照组(t≥3.858,P<0.0 5),且对血小板衍生生长因子(PDGF)促增殖效应的敏感性显著减弱;Ⅰ、Ⅲ型胶原和α-SMA的表达显著减少(t≥6.790,P<0.01);凋亡发生率显著高于对照组(x2≥14.157,P<0.01),电镜下可见典型凋亡细胞。 结论 抗PDGFR-β核酶的真核表达载体可在细胞内稳定表达,能有效切割靶RNA,抑制HSC增殖及胶原合成,并诱导其凋亡。为抗肝纤维化治疗提供了新的靶点和手段。     

Specific shRNA targeting of FAK influenced collagen metabolism in rat hepatic stellate cells

AIM:To investigate the effects and mechanism of disruption of focal adhesion kinase(FAK) expression on collagen metabolism in rat hepatic stellate cells(HSC).METHODS:The plasmids expressing FAK short hairpin RNA(shRNA) were transfected into HSC-T6 cells,and the level of FAK expression was determined by both real-time quantitative polymerase chain reaction(QPCR) and Western blotting analysis.The production of type collagen and type collagen in FAK-disrupted cells was analyzed by real-time Q-PCR.The level of ...     

氧化苯砷体外对大鼠原代肝星状细胞活化的阻抑作用研究*

目的 探讨氧化苯砷(PAO)对肝星状细胞（HSC）活化的影响。方法 采用密度梯度离心法提取SD大鼠原代HSC,在倒置显微镜下观察HSC形态的改变;以25、50、100、150和200 nmol/L浓度PAO处理活化的HSC-T6细胞,以四甲基偶氮唑盐（MTT）法评估PAO的细胞毒性;分别以25、50、100 nmol/L浓度的PAO处理离体培养4 d的HSC 72 h,并设对照组,采用Western blot和Real-time PCR法检测各组细胞α-SMA和I型胶原mRNA和蛋白表达。结果 原代HSC离体培养过程中α-SMA表达量逐渐升高,与培养1 d时（0.762±0.062）比,培养4 d时其α-SMA蛋白表达【(1.51±0.045),P<0.05】 显著升高;PAO在25~100 nmo/L浓度范围内对活化的HSC无明显的细胞毒性,但能浓度依赖性抑制活化的HSC α-SMA 和I型胶原mRNA水平和蛋白表达。结论 离体培养4 d时,HSC呈初始活化状态。PAO在25~100 nmol/L范围可浓度依赖性地阻抑离体培养的HSC的自发激活,提示PAO有潜力成为一类新型的抗肝纤维化药物。     

小分子干扰RNA沉默高迁移率族蛋白B1抑制肝星状细胞Ⅰ型和Ⅲ型胶原合成*

目的 研究小分子干扰RNA（siRNA）干扰高迁移率族蛋白B1（HMGB 1）表达对肝星状细胞（HSC） Ⅰ型和Ⅲ型胶原表达的影响。方法 将化学合成的HMGB 1基因特异性siRNA以脂质体包裹,转染HSC-T6细胞,设阴性对照和空白对照,抽提细胞总RNA和蛋白质,采用Western blot法检测细胞Ⅰ型和Ⅲ型胶原表达情况;采用细胞免疫荧光法检测Ⅰ型和Ⅲ型胶原表达与定位;采用酶联免疫吸附法检测培养上清液中Ⅰ型和Ⅲ型胶原水平。结果 转染HMGB 1基因特异性siRNA的HSC-T6细胞Ⅰ型和Ⅲ型胶原蛋白水平显著下调,免疫细胞化学检测也提示转染siRNA 后细胞内Ⅰ型和Ⅲ型胶原水平较对照组明显降低;在培养72 h时,上清液Ⅰ型胶原和Ⅲ型胶原水平分别较对照组下降了（46.36±3.82） %和（41.92±3.58） %（F=33.14,P<0.01;F=27.56,P<0.01）。结论 HMGB 1特异性siRNA能高效抑制HSC-T6细胞胶原的合成和分泌,因而可能具有预防和治疗肝纤维化的潜力。     

BMP-7过表达抑制大鼠肝星状细胞上皮-间叶转化

目的观察慢病毒介导的BMP-7高表达是否能抑制大鼠HSC-T6细胞发生上皮-间叶转化（epithelial to mesenchymal tran-sition,EMT）,并能拮抗TGF-β1的促EMT作用。方法构建大鼠BMP-7慢病毒表达载体,体外感染HSC-T6细胞株,将成功感染BMP-7重组慢病毒的细胞给予TGF-β1（5 ng/mL）或溶酶体处理。Real-time PCR检测α-SMA、S100A4、E-cadherin mRNA转录水平。Western blotting检测α-SMA、S100A4、E-cadherin、Ⅰ型胶原蛋白表达水平。结果 BMP-7慢病毒感染HSC-T6后,无论TGF-β1存在与否,real-time PCR检测到α-SMA、S100A4 mRNA转录下调,E-cadherin转录上调。Western blotting显示α-SMA、S100A4及Ⅰ型胶原蛋白表达下调,E-cadherin蛋白表达上调。实验组与空病毒对照组比较,差异有统计学意义（P〈0.05）,空病毒对照组与空白组比较,差异无统计学意义。结论 BMP-7能有效拮抗TGF-β1对HSC-T6的促EMT作用,可能成为肝纤维化治疗的新途径。     

Seroepidemiology of Helicobacter pylori infection in elderly people in the Beijing region,China

AIM:To investigate seroepidemiology of cagA+and vacA+strains of Helicobacter pylori(H.pylori)in an elderly population in Beijing and to determine risk factors for seropositivity.METHODS:A total of 2006 elderly persons(>60years)were selected using a random cluster sampling method in different parts of the Beijing area(urban,suburban and mountainous districts).Structured questionnaires were completed during home visits,including history of H.pylori infection,history of gastrointestinal diseases,diet types,hygiene habits,occupation and economic status.Blood samples(2 mL)were collected from each participant,and serum IgG antibodies to cagA,vacA and H.pylori urease antigens were measured by immunodetection.RESULTS:The prevalence of H.pylori infection in elderly subjects was 83.4%and the typeⅠH.pylori strain infection rate was 56%.The seroprevalence for typeⅠH.pylori strain infection in urban and suburbandistricts was higher than that in the mountainous areas(P<0.001).Elderly subjects who had previously performed manual labor or were in the young-old age group(age<75 years)had a higher seroprevalence of H.pylori infection than those who had previously performed mental labor or were in the oldest-old age group(age≥75 year)(P<0.05).The typeⅠH.pylori strain infection rate in the elderly with vegetarian diets was higher than in those eating high-protein foods(P<0.001).There was no significant difference in the prevalence of H.pylori strains between male and female elderly participants(P>0.05).CONCLUSION:TypeⅠH.pylori seroprevalence is higher in elderly people.The distribution of strains of H.pylori is significantly affected by age,area and dietary habits.     

siRNA沉默β-Catenin对肝星状细胞工、Ⅲ型胶原表达的影响

目的 研究siRNA干扰β-Catenin表达、阻断Wnt/β-Catenin信号通路对肝星状细胞(HSC)Ⅰ、Ⅲ型胶原表达的影响.方法 将化学合成siRNA β-Catenin以Lipofectamine包裹,转染HSC-T6细胞,设阴性对照和空白对照,抽提细胞总RNA及蛋白质,收集培养上清液,应用反转录-聚合酶链反...     

RNA干扰bcl-2基因的筛选及对肝星状细胞生物活性的影响

目的研究小干扰RNA（shRNA）重组载体介导抑制大鼠肝星状细胞（hepaticstellatecell，HSC）bcl-2基因的表达，初步观察其对HSC生物活性的影响。方法设计有小发夹结构的3条DNA序列构建重组质粒载体pGPU6-GFP，脂质体转染HSC—T6细胞株以荧光定量PCR和Westernblot筛选鉴定，通过CCK-8法及AnnexinV／PI双标记流式细胞术检测、观察其对HSC生长的影响。结果pGPU6-GFP—shRNA1、shRNA2均能抑制bcl-2mRNA和蛋白表达（P〈0．05），pGPU6-GFP—shRNAl转染HSC．T6株72h后对bcl-2基因抑制达80％，且HSC—T6体外生长明碌受到抑制，早期凋亡率为33．34％～44．12％。结论bel-2小发夹RNA重组载体shRNA1能最有效抑制HSC—T6中bcl-2的表达与细胞生长，促进凋亡，为下一步探索肝纤维化基因治疗提供实验依据。