大鼠肝纤维化过程中肝组织黏着斑激酶表达增加

本研究采用胆总管结扎 (BDL)方法建立大鼠肝纤维化模型 ,应用免疫组织化学、Westernblotting技术及逆转录聚合酶链式反应 (RT PCR)方法 ,研究了FAK及其mRNA在肝纤维化不同时期肝组织中的分布及含量的动态变化 ;用免疫组织化学方法测定α 平滑肌肌动蛋白 (α SMA)表达。结果显示 :正常肝组织有少量α SMA、FAK分布 ,随着肝纤维化发展 ,α SMA、FAK阳性细胞明显增多 ;正常大鼠肝组织中亦有FAK蛋白、FAKmRNA表达 ,造模 4周表达最多。FAK与α SMA呈显著正相关 (r=0.96 3,P <0.0 5 )。提示肝纤维化形成过程中FAK及其mRNA表达明显增加 ,FAK在HSCs增殖及肝纤维化形成过程中发挥作用     

黏着斑激酶相关非激酶质粒转染对肝星状细胞凋亡的影响

目的：应用黏着斑激酶相关非激酶（FRNK）表达质粒瞬时转染肝星状细胞（HSCs），探讨FRNK选择性抑制黏着斑激酶(FAK)磷酸化对FN刺激的HSCs凋亡的影响。方法:在体外培养HSCs，以FN刺激HSCs增殖，采用脂质体介导的方法进行FRNK表达质粒转染。应用膜联蛋白（Annexin-V）/碘化丙啶（PI）双标记流式细胞术、DNA凝胶电泳技术和透射电镜技术检测细胞的凋亡，Western blotting及RT-PCR方法检测FRNK、FAK、p-FAK（Tyr397）、caspase-3蛋白及其mRNA表达。结果:FRNK表达质粒成功转染HSCs，在翻译后水平抑制FAK磷酸化；FRNK表达质粒转染HSCs 48 h后，细胞凋亡率增加，与空质粒组之间有显著差异［（25.37±1.92）% vs（9.28±1.05）%］，P<0.01，伴随caspase-3在翻译和转录水平的增高［（264.17±12.60 vs 185.82±9.69），P<0.01；（4.19±0.48 vs 1.07±0.27），P<0.01］。结论:在脂质体介导下瞬时转染FRNK表达质粒，可使外源性的FRNK在HSCs内大量表达，在翻译后水平抑制FAK磷酸化；可以诱导FN刺激的HSCs发生凋亡。     

黏着斑激酶酪氨酸磷酸化促大鼠肝纤维化形成及其可能机制

目的探讨在肝纤维化发生中,黏着斑激酶(FAK)酪氨酸磷酸化与肝星状细胞(HSC)增殖的关系,并从细胞周期角度探讨其促HSC增殖的机制。方法采用胆总管结扎(BDL)方法建立大鼠肝纤维化模型;免疫组织化学方法测定α-平滑肌肌动蛋白(α-SMA)表达;Western blot检测p-FAK(Tyr397)、细胞周期蛋白D1(cyclin D1)和细胞周期蛋白依赖激酶4(CDK4)在肝组织中的含量。结果正常大鼠肝组织有少量α-SMA分布,随着肝纤维化发展,α-SMA阳性细胞明显增多;肝组织中p-FAK(Tyr397)、cyclin D1及CDK4蛋白表达逐渐增加,造模4周时达峰值。多元相关分析示α-SMA与p-FAK(Tyr397)正相关(r=0.964,P<0.01);α-SMA与cyclin D1、CDK4正相关(r=0.953,0.906;P<0.01);p-FAK(Tyr397)与cyclin D1、CDK4亦明显正相关(r=0.969,0.893;P<0.01)。结论FAK磷酸化促HSC增殖及肝纤维化形成机制可能与调控细胞周期相关蛋白有关。     

PTEN表达下调促进体外活化大鼠肝星状细胞黏附

目的探讨腺病毒介导的短发夹RNA(shRNA)下调第10号染色体缺失的磷酸酶张力蛋白同源物PTEN基因的表达对体外培养的活化肝星状细胞(HSC)黏附的影响及其信号传导机制。方法体外培养活化大鼠肝星状细胞系HSC-T6,以腺病毒为载体将靶向PTEN的RNA干扰(shRNA)瞬时转染HSC;实验分为3组:1)对照组,在腺病毒转染时以DMEM代替病毒液;2)Ad-GFP组,转染仅表达绿色荧光蛋白(GFP)的空病毒Ad-GFP;3)Ad-shRNA/PTEN组,转染携带靶向PTEN的shRNA并表达GFP的重组腺病毒Ad-shRNA/PTEN。用实时荧光定量PCR法检测HSC的PTEN mRNA表达;Western blot检测HSC的PTEN、黏着斑激酶(FAK)、磷酸化FAK[p-FAK(Tyr397)]蛋白表达;甲苯胺蓝染色法及四甲基偶氮唑盐(MTT)法测定HSC黏附能力。结果腺病毒感染HSC 48 h,Ad-shRNA/PTEN组PTEN蛋白及mRNA表达明显低于对照组及Ad-GFP组(P0.05);Ad-shRNA/PTEN组HSC的p-FAK(Tyr397)表达较对照组及Ad-GFP组显著升高(P0.05);Ad-shRNA/PTEN组HSC黏附细胞数及黏附率较对照组及Ad-GFP组明显增加(P0.05)。结论 PTEN表达下调可通过上调FAK信号传导活性促进体外活化HSC的黏附。     

膜型基质金属蛋白酶-1在黏着斑激酶相关非激酶调控肝星状细胞胶原代谢中的作用

目的： 探讨黏着斑激酶相关非激酶（FRNK）对纤维连接蛋白（FN）刺激的肝星状细胞（HSC）膜型基质金属蛋白酶-1（MT1-MMP）表达的影响并探讨MT1-MMP在FRNK调控HSC胶原代谢中的作用。方法：应用体外细胞培养技术,脂质体介导法进行FRNK质粒瞬时转染;采用Western blotting法测定FRNK蛋白在瞬时转染时相应的表达,鉴定转染效果;分别应用Western blotting和RT-PCR方法测定MT1-MMP在HSC中的相应表达。结果：FRNK质粒成功转染HSC,于转染48 h时,FRNK蛋白表达最强,P<0.05;FRNK转染后在基因水平上：MT1-MMP mRNA表达明显增加;翻译蛋白水平上：FRNK质粒转染HSC 48 h后,MT1-MMP蛋白表达量显著升高。结论：脂质体介导下FRNK质粒转染,可使外源性FRNK在HSC内大量表达,FRNK可能通过上调MT1-MMP值来抑制HSC胶原合成。     

FRNK抑制体外肝星状细胞增殖

目的用FRNK表达质粒瞬时转染FN诱导的HSCs,探讨FRNK对HSCs增殖的影响。方法在脂质体介导下用FRNK表达质粒瞬时转染HSCs,用改良的MTT技术测定细胞增殖,用Western blot及RT-PCR技术检测各指标蛋白及mRNA表达。结果与nFRNK组相比,FRNK在FN诱导的HSCs中大量表达后,于12、24和48h的增殖抑制率分别为20.07%、26.16%和29.77%（P〈0.01）;FRNK抑制FAK磷酸化和ERK1、p-ERK的表达,而FN则促进FAK、ERK1和p-ERK表达。结论在脂质体介导下瞬时转染FRNK表达质粒,可时间依赖性的抑制HSCs增殖;FAK-ERK信号传导通路可能参与了该过程。     

FAK基因的RNA干扰对肝星状细胞生物活性的影响

目的 探讨靶向黏着斑激酶（FAK）基因的短发卡状RNA（shRNA）对大鼠肝星状细胞系HSC-T6活化与增殖的影响。方法 分别设计2对有小发卡结构的DNA序列及1对非特异对照序列,构建重组质粒载体,经阳离子聚合物介导转染HSC-T6细胞。通过real-time PCR与Western blot进行筛选鉴定,改良MTT法观察细胞增殖,Western blot检测HSC活化的标志物α-SMA的表达。结果 shRNA1、shRNA2均能抑制FAK mRNA和蛋白表达（P＜0.05）,其中shRNA2对FAK基因抑制率达76.82%,且可明显抑制HSC-T6细胞α-SMA的表达及细胞增殖。结论 靶向FAK基因的shRNA可以抑制HSC-T6细胞的活化与增殖。     

黏着斑激酶反义寡核苷酸对肝星状细胞增殖及活化的影响

黏着斑激酶(Focal adhesion kinase,FAK)在肝星状细胞(Hepatic stellate cells,HSC)的激活过程中起重要作用.本文旨在研究FAK反义寡核苷酸(FAK antisense oligonucleotides,FAK-ASON)能否抑制体外培养的大鼠肝星状细胞的增殖及活化.用链霉蛋白酶-胶原酶原位灌注、Nycodenz密度梯度离心法分离大鼠HSC,并在体外培养使其激活后,将FAK-ASON转染至活化的HSC.应用MTT法观察HSC细胞增殖的变化,并用RT-PCR、Western blot观察HSC活化的标志物α-平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)表达的变化.MTT结果显示FAK-ASON可明显抑制活化HSC的增殖;FAK-ASON处理48 h后,HSC α-SMA mRNA及蛋白的表达亦明显下降.结果进一步提示FAK在HSC激活过程中的作用,而FAK-ASON有可能成为潜在的抗肝纤维化治疗药物.     

黏着斑激酶促进人肺动脉平滑纲细胞增生

目的探讨黏着斑激酶(focal adhesion kinase,FAK)是否参与人肺血管平滑肌细胞增殖。方法将纤黏连蛋白(fibronectin,FN)预处理的培养人肺血管平滑肌细胞进行分组,采用不同浓度的FAK正义寡核苷酸转染,应用免疫沉淀及免疫印迹方法测定FAK的活性及蛋白质表达,并利用MTT比色法及3H-TdR掺入法测定细胞增殖情况。结果FAK正义寡核苷酸转染后,FAK的活性及蛋白质表达量均随着剂量增加而增加,呈浓度和时间依赖性地促进细胞增殖及3H-TdR掺入。结论FAK促进人肺动脉平滑肌细胞增殖。     

FRNK质粒转染抑制肝星状细胞胶原合成

目的：探讨黏着斑激酶相关非激酶（FRNK）对纤维连接蛋白（FN）刺激的肝星状细胞（HSCs）胶原合成的影响。方法:应用体外细胞培养技术,脂质体介导法进行FRNK质粒瞬时转染;采用Western blotting方法测定FRNK蛋白在HSCs的表达,鉴定转染效果;［3H］-Pro掺入法检测HSCs总胶原和Ⅰ型胶原的合成能力。结果:FRNK质粒成功转染HSCs,于转染48 h时FRNK蛋白表达最强（P<0.05）;在FRNK转染HSCs 48 h后总胶原合成能力（498.17±73.20）较空质粒组（748.33±61.30）显著下降（P<0.01）;在FRNK转染HSCs 48 h后 Ⅰ型 胶原合成能力（163.17±23.80）较空质粒组（371.58±15.44）亦显著下降（P<0.01）。结论:FRNK可以使HSCs总胶原和Ⅰ型胶原合成能力降低,提示其对肝星状细胞胶原合成功能具有负调控作用。     

Down-regulation of focal adhesion kinase by short hairpin RNA increased apoptosis of rat hepatic stellate cells

Focal adhesion kinase (FAK) plays an essential role in the activation of hepatic stellate cells (HSC). The role of FAK on proliferation and apoptosis of fibronectin (FN)-stimulated HSC was investigated using short hairpin RNA (shRNA)-mediated gene silencing technology. FAK shRNA decreased the expressions of FAK, p-FAK (Tyr(397)), ERK(1), and p-ERK(1). FAK gene silencing also inhibited HSC proliferation by 11.08% at 12-h, 15.12% at 24-h, and 28.62% at 48-h post-transfection. Flow cytometric analysis (FACS) revealed that the apoptotic rate at 24 h was increased in the FAK shRNA plasmid group compared with the HK group (8.29 ± 0.79% vs 2.70 ± 0.31%, p < 0.01). TUNEL also confirmed the increase in the rate of apoptosis (19.00 ± 0.92% vs 7.63 ± 0.70%, p < 0.01), and studies showed that the caspase-3 expression was increased while the ratio of Bcl-2 to Bax was decreased. Together, these data show that FAK regulates HSC proliferation and induces the apoptosis of HSC via the caspase-3 and Bcl-2/Bax pathway.     

The biphasic nature of hypoxia-induced directional migration of activated human hepatic stellate cells

Liver fibrogenesis is sustained by pro-fibrogenic myofibroblast-like cells (MFs), mainly originating from activated hepatic stellate cells (HSC/MFs) or portal (myo)fibroblasts, and is favoured by hypoxia-dependent angiogenesis. Human HSC/MFs were reported to express vascular-endothelial growth factor (VEGF) and VEGF-receptor type 2 and to migrate under hypoxic conditions. This study was designed to investigate early and delayed signalling mechanisms involved in hypoxia-induced migration of human HSC/MFs. Signal transduction pathways and intracellular generation of reactive oxygen species (ROS) were evaluated by integrating morphological, cell, and molecular biology techniques. Non-oriented and oriented migration were evaluated by using wound healing assay and the modified Boyden's chamber assay, respectively. The data indicate that hypoxia-induced migration of HSC/MFs is a biphasic process characterized by the following sequence of events: (a) an early (15 min) and mitochondria-related increased generation of intracellular ROS which (b) was sufficient to switch on activation of ERK1/2 and JNK1/2 that were responsible for the early phase of oriented migration; (c) a delayed and HIF-1α-dependent increase in VEGF expression (facilitated by ROS) and its progressive, time-dependent release in the extracellular medium that (d) was mainly responsible for sustained migration of HSC/MFs. Finally, immunohistochemistry performed on HCV-related fibrotic/cirrhotic livers revealed HIF-2α and haem-oxygenase-1 positivity in hepatocytes and α-SMA-positive MFs, indicating that MFs were likely to be exposed in vivo to both hypoxia and oxidative stress. In conclusion, hypoxia-induced migration of HSC/MFs involves an early, mitochondrial-dependent ROS-mediated activation of ERK and JNK, followed by a delayed- and HIF-1α-dependent up-regulation and release of VEGF.     

辛二酰苯胺异羟肟酸对人肝星状细胞增殖和凋亡的影响

目的研究组蛋白去乙酰化酶抑制剂辛二酰苯胺异羟肟酸(SAHA)对人肝星状细胞系LX-2增殖及凋亡的影响及其可能机制。方法体外应用SAHA作用于LX-2细胞,倒置显微镜观察LX-2细胞形态,MTT法检测细胞增殖;荧光显微镜及流式细胞仪Annexin V-FITC/PI法检测细胞凋亡率;Western blot检测α-SMA、Ⅰ型胶原、ac H3K9、ac H3K14和ac H3K18蛋白表达。结果 SAHA呈剂量依赖性显著抑制LX-2细胞增殖(P0.05);SAHA对LX-2细胞凋亡具有呈时间依赖性的促进作用(P0.05);SAHA处理LX-2细胞后,α-SMA和Ⅰ型胶原蛋白表达水平明显降低(P0.05),而ac H3K9、ac H3K14和ac H3K18乙酰化修饰水平明显升高(P0.01)。结论 SAHA抗肝纤维化的机制可能与下调α-SMA及Ⅰ型胶原蛋白表达,上调组蛋白ac H3K9、ac H3K14和ac H3K18乙酰化修饰水平有关。     

Pentoxifylline inhibits hepatic stellate cells proliferation via the Raf/ERK pathway

Pentoxifylline (PTX), which is a xanthine derivative, is a well-known suppressor of tumor necrosis factor-alpha (TNF-alpha) production in inflammatory cells and has also been shown to inhibit collagen synthesis in hepatic stellate cells (HSCs) in vitro. The present study aimed to evaluate the effects of PTX on proliferation in HSCs as mediated by the Raf/MEK/extracellular-signal-regulated kinase (ERK) signaling pathway. The rat hepatic stellate cell line T6 and activated primary rat HSCs were used in this study. The proliferation rate of the cells treated with 1 mM PTX significantly decreased compared with that of the control in T6 cells (78.3 ± 6.03% at 12 h, 61.0 ± 7.55% at 24 h, and 44.7 ± 2.08% at 48 h, p < 0.05). PTX (1 mM) also decreased the fraction of the HSC population in the S and G2/M-phases of the cell cycle in primary activated rat HSCs. The Raf-1 inhibitor GW5074 and the ERK inhibitor U0126 had inhibitory effects that were similar to those of PTX on HSC proliferation. In addition, PTX inhibited the phosphorylation of Raf-1 (p-Raf-1) and ERK (p-ERK) in a dose- and time-dependent manner in HSCs. These data provide evidence that PTX suppresses HSC proliferation via the Raf/MEK/ERK pathway.     

RGDyK环肽对肝星状细胞增殖和迁移的影响

目的：探讨RGDyK环肽对活化肝星状细胞中整合素αvβ3表达和细胞迁移的影响。方法分离SD大鼠肝星状细胞,体外传代培养诱导细胞活化,用人工合成的整合素αvβ3特异配基RGDyK环肽处理肝星状细胞,MTT法计算其生长抑制率,通过免疫化学和荧光染色,RT-PCR和Western Blot分析,与对照组比较肝星状细胞中整合素αvβ3和α-SMA的表达变化,划痕实验观察RGDyK环肽对活化肝星状细胞迁移的影响。结果与对照组相比,RGDyK环肽抑制肝星状细胞增殖并有明显的量效关系, RGDyK环肽下调肝星状细胞中整合素αvβ3和α-SMA的在mRNA和蛋白质水平的表达（P<0.05）,降低肝星状细胞的迁移率（P<0.01）。结论 RGDyK环肽抑制肝星状细胞增殖、收缩和迁移等生物行为与下调活化肝星状细胞整合素αvβ3表达有关。