高脂培养抑制LPS诱导的HSC-T6 细胞活化*

摘要目的：鉴定高脂培养对肝星形细胞活化的影响。方法：培养HSC-T6 细胞系,加入含有游离脂肪酸的高脂培养基处理,利用 LPS 处理活化,通过检测α-SMA 的表达分析星形细胞的活化程度,通过Q-PCR分析HSCs 细胞胶原的表达,通过Q-PCR实验分 析LPS相关通路靶基因表达情况情况。结果：高脂培养能够抑制LPS 诱导的HSC-T6 细胞增殖,降低HSC-T6 细胞α-SMA 和胶 原I和TIMP-1 表达的水平,Q-PCR 的分析表明,高脂培养能够抑制HSCs活化后的NF-κB 通路下游靶基因MCP-1 和IL-6 的表 达。结论：在体外培养实验中,高脂培养能够抑制LPS诱导的HSC-T6 细胞活化。     

二氢杨梅素通过抑制铁自噬而抑制铁超载诱导的肝星状细胞活化

目的 肝星状细胞（HSCs）是肝纤维化（HF）过程中细胞外基质（ECM）的主要来源,在HF的发生发展中起着重要作用。二氢杨梅素（DMY）具有保肝作用,但机制不清。本研究观察了DMY对枸橼酸铁铵（FAC）诱导HSC-T6细胞活化的影响,并探讨了可能的机制。方法 采用MTT法检测细胞活力,ELISA法检测培养上清中ECM主要成分的含量,普鲁士蓝染色观察HSC-T6细胞铁沉积,比色法测定HSC-T6细胞总铁含量,钙黄绿素法检测细胞内游离铁水平,透射电镜观察HSC-T6细胞超微结构。蛋白质免疫印迹法检测铁蛋白重链1（FTH1）、α平滑肌肌动蛋白（α-SMA）、核受体辅活化子4（NCOA4）、微管相关蛋白1轻链3（LC3）和p62/SQSTM1的表达。结果 与FAC组比较,DMY+FAC组细胞培养液中ECM主要成分、细胞内总铁和游离铁水平、细胞中α-SMA、NCOA4和LC3-Ⅱ表达以及LC3-Ⅱ/LC3-Ⅰ比值均显著降低,而FTH1和p62蛋白表达显著上调。雷帕霉素部分阻断DMY抑制FAC诱导的HSCs活化的作用。结论 DMY可抑制铁超载诱导的HSCs活化,其机制可能与抑制铁自噬有关。     

FGF-21抑制HSC-T6细胞活化的抗肝纤维化作用及其机制的研究

目的:探索成纤维细胞生长因子21(FGF-21)对肝星形细胞T6(HSC-T6)活化的作用及其作用机制。方法:1640+10%胎牛血清的培养基培养HSC-T6细胞,实验分为5组:正常对照组(Control)、模型组(Model 20 m M乙醇处理细胞12 h)、低剂量FGF-21组(LFGF-21,0.5μmol/L)、中剂量FGF-21组(MFGF-21,1.0μmol/L)和高剂量FGF-21组(HFGF-21,2.0μmol/L)。Real-time PCR检测α-平滑肌肌动蛋白(α-SMA)、胶原蛋白Ⅰ(CollagenⅠ)、基质金属蛋白酶-2(MMP2)、基质金属蛋白酶-9(MMP9)和Notch2的m RNA水平,Western blot检测CollagenⅠ、α-SMA、MMP2、MMP9和Notch2的蛋白水平,ELISA检测IL-1β、TNF-α的蛋白水平。结果:模型组α-SMA、CollagenⅠ、MMP2、MMP9、IL-1β、TNF-α、Notch2的水平高于对照组(P0.05),HFGF-21组α-SMA、CollagenⅠ、MMP2、MMP9、IL-1β、TNF-α、Notch2的水平均低于模型组(P0.05)。结论:FGF-21可抑制Notch2的表达,抑制炎症反应,从而抑制HSC的活化,发挥抗肝纤维化作用。     

剪切应力环境下的内皮祖细胞对肝星状细胞增殖和生物功能的影响

目的：研究流体剪切应力条件下的内皮祖细胞（EPCs）对肝星状细胞（HSCs）增殖、粘附、迁移、凋亡等生物学功能以及成纤维化因子α-平滑肌肌动蛋白（α-SMA）、胶原I （Col-I）、胶原III （Col-III）表达的影响。方法：将HSCs与EPCs分别接种于共培养小室的上层和下层,共培养24 h后,给EPCs细胞施加12 dyne/cm²剪切应力,持续24 h。消化细胞,采用CCK-8法检测HSCs的增殖;流式细胞术检测HSCs的凋亡率;细胞贴壁法检测HSCs的粘附功能;Boyden小室检测HSCs的迁移;荧光定量PCR法及Western blot分别检测HSCs的α-SMA、Col-I、Col-III mRNA和蛋白质的表达情况。结果：在剪切应力条件下,EPCs生态小境能明显抑制HSCs的增殖、粘附和迁移能力,促进HSCs凋亡,下调HSCs中Col-I、Col-III mRNA和蛋白质的表达。结论：在剪切应力条件下,EPCs生态小境对HSCs纤维化的发展具有一定抑制作用。     

间充质干细胞来源的外泌体通过TGF-β1/Smad2/3信号通路抑制高糖诱导的成纤维细胞转分化

心脏纤维化是糖尿病患者心肌功能障碍的主要原因。成纤维细胞转分化为成肌纤维细胞是心脏纤维化过程中的一个关键性事件。该研究的目的是探究高糖诱导成纤维细胞转分化的分子机制,并找寻抑制成纤维细胞转分化的方法。结果显示,经高糖处理的BJ细胞(人皮肤成纤维细胞系)与正常BJ细胞相比,α-平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)的表达明显上调。通过使用SB525334或转化生长因子-β1(transforming growth factor-β1,TGF-β1)si RNA抑制TGF-β1/Smad2/3信号通路的活化,发现α-SMA和胶原I的蛋白质水平及Smad2/3的磷酸化水平均降低。同时,SB525334也抑制了高糖诱导的BJ细胞增殖。大鼠骨髓间充质干细胞来源的外泌体(mesenchymal stem cell-derived exosome,MSC-Exo)通过降低Smad2/3磷酸化水平,抑制高糖诱导的α-SMA表达。综上所述,高糖通过激活TGF-β1信号通路导致BJ细胞的转分化,而MSC-Exo通过抑制该通路防止BJ细胞的转分化。     

小蘖碱抑制游离脂肪酸诱导小鼠肝实质细胞脂肪变性

目的:探讨小蘖碱(Berberine)对游离脂肪酸(free fatty acids,FFAs)诱导的小鼠肝实质细胞脂肪变性的影响。方法:胶原酶灌注分离BALB/c小鼠原代肝实质细胞并体外培养。分对照组,高脂组,高脂加小蘖碱处理组。体外测定细胞内甘油三酯的含量。利用油红染色观察细胞的脂肪样变性。通过Western印迹法检测肝实质细胞内MAPK相关信号通路磷酸化的变化。实时定量PCR检测肝实质细胞中与脂肪化密切相关的mi R-122的表达和相关靶基因的表达改变。结果:与高脂组比较,小蘖碱处理组肝实质细胞内甘油三酯含量降低,脂肪颗粒减少,脂肪变性明显改善,并具有明显的剂量效应,小蘖碱能够抑制FFAs诱导的JNK通路磷酸化。Q-PCR结果表明小蘖碱能够促进肝实质细胞内mi R-122的表达,并降低脂肪化相关基因Dgat2的表达。结论:小蘖碱能够显著改善高脂诱发的肝脂肪变性,抑制JNK通路磷酸化,其机制可能同mi R-122通路相关。     

五味子乙素对大鼠肝星状细胞增殖和胶原基因表达合成的影响

目的观察五味子乙素在大鼠肝星状细胞（HSCs）增殖,胶原表达合成方面的作用。方法经在体灌流消化大鼠肝脏分离HSCs,培养于DMEM培养基中,用^3H-TdR和^3H-pro掺入试验测定五味子乙素对HSCs的增殖和胶原合成影响,并用原位杂交方法探讨了其对HSCⅠ、Ⅲ型前胶原基因的表达作用。结果对于培养活化的HSCs,五味子乙素对HSCs摄取^3H-TdR没有明显影响,但在40μmol/L时,剂量依赖地抑制HSCs摄取^3H-proline,并在80μmol/L降低Ⅰ型前胶原基因表达（P〈0.05）。结论五味子乙素具有降低HSCs胶原基因表达合成作用。     

siRNA对肝纤维化的抑制作用

目的：研究肝星状细胞（use）中smad2特异性小干扰RNA（siRNA）对I型胶原表达的抑制作用,探讨抗肝纤维化的基因治疗新方法。方法：设计合成靶向Smad2基因的siRNA,将筛选成功的siRNA瞬时转染入体外培养的肝星状细胞（HSC）,并给予转化生长因子p（TGF．B）刺激,应用RT—PCR和Westernblot技术检测对照组与实验组I型胶原mRNA水平和蛋白水平表达差异,研究siRNA对I型胶原表达的抑制作用。结果：siRNA能明显降低肝星状细胞中Smad2的RNA和蛋白的表达水平,证实筛选的siRNA有效,能特异性抑制Smad2的基因表达;TGF-β刺激肝星状细胞后,与对照组比较,siRNA转染组细胞外基质（ECM）成分I型胶原的表达水平明显降低（P〈0．05）。结论：siRNA能够抑制TGFβ对肝星状细胞的激活,阻断TGFB—Smads传导通路,使I型胶原分泌下调,有效抑制TGFB诱导的肝纤维化。     

TGF-β1激活肝星状细胞并促进血管内皮细胞新生血管形成

该研究旨在探讨转化生长因子-β1(transforming growth factor-β1,TGF-β1)在肝星状细胞(hepatic stellate cells,HSCs)激活中的机制以及活化HSCs促进内皮细胞血管新生(angiogenesis)的作用效果。运用q RT-PCR检测α-SMA、Smad2/3、VEGFA和TGF-β1-RI的m RNA水平;Western blot检测α-SMA、Smad2/3、p-Smad2/3、VEGFA和TGF-β1-RI的蛋白质水平;基质胶(matrigel)血管形成实验检测活化HSCs的促人脐静脉血内皮细胞(human umbilical vein endothelial cells,HUVECs)血管形成作用。TGF-β1作用后的HSCs高表达α-SMA以及经典的TGF-β1/TGF-β1-RI/Smad2/3信号通路下游相关的TGF-β1-RI和Smad2/3等,具备了活化表型并能促进内皮细胞血管新生。结果表明,TGF-β1信号通过经典的Smad2/3通路激活了HSCs,使激活后的HSCs通过分泌VEGFA具备了促进内皮细胞血管新生的功能。     

奥美沙坦减轻高脂饮食诱导的非酒精性脂肪肝病的机制研究

目的探讨奥美沙坦对于高脂诱导的非酒精性脂肪肝病（NAFLD）的影响及可能机制。方法健康雄性8周龄C57BL／6小鼠24只随机分为高脂组（n=16）和正常饮食组（n=8）,高脂组小鼠高脂饮食（60％的脂肪）12w后再随机分为高脂饮食对照组（n=8）、高脂饮食治疗组（n=8）。高脂饮食治疗组小鼠给予0．75mg／kg／d的奥美沙坦灌胃8w,灌胃结束后处理小鼠,留取空腹血样本检测AST和ALT。肝组织冰冻切片行油红O染色观察脂肪变;石蜡切片行HE和F4／80免疫组化染色观察肝脏炎症变化;实时荧光定量PCR检测肝脏TNF-α和IL-6mRNA的表达水平;WesternBlot检测肝组织中IκB-α、p-IκBa、NF—κB信号通路的活化。结果奥美沙坦显著抑制了高脂诱导的NAFLD脂肪变性,并明显改善肝功能。实时荧光定量PCR结果表明奥美沙坦能显著降低肝脏组织中TNF-α和IL-6mRNA表达水平（P〈0．05）;Western Blot结果显示奥美沙坦显著抑制肝脏NF-κB信号通路活化。结论奥美沙坦显著抑制NAFLD小鼠肝脏炎性病变而保护肝功能,其机制与抑制NF-κB信号通路活化以及降低肝脏TNF-α和IL-6mRNA水平有关。     

红景天苷对LPS诱导的HSC-T6细胞增殖作用及机制研究

目的：观察红景天苷（Salidroside,Sal）对大鼠肝星状细胞（hepaticstellatecell,HSC）一T6增殖的影响,并探讨一氧化氮（NO）在此过程中的作用。方法：选择脂多糖（LPS）活化HSC—T6,采用不同浓度的Sal,作用于经LPS活化的大鼠HSC-T6,24小时后进行如下实验：噻唑兰（MTT）比色法检测HSC—T6增殖;NO荧光探针（DAF-FMDA）检测细胞内NO浓度;Westem-blot检测INOS蛋白水平。结果：在LPS作用于HSC．T6细胞24小时后,与对照组相比,细胞增殖增加（P〈0．01）,在Sal作用下,HSC-T6细胞增殖与LPS组相比受到抑制（P〈0．01）,并呈浓度依赖性;在Sal处理HSC．T6细胞24小时后,细胞内NO水平有所上升,并呈浓度依赖性增加（P〈O．01）;Sal预处理后的HSC—T6细胞,iNOS蛋白表达有所升高（P〈0．01）。结论：Sal对HSC—T6细胞的增殖具有浓度依赖性的抑制作用,NO可能是抑制增殖的因素之一。     

Inhibitory Effect of Tanshinone IIA on Rat Hepatic Stellate Cells

Background

Anti-inflammation via inhibition of NF-κB pathways in hepatic stellate cells (HSCs) is one therapeutic approach to hepatic fibrosis. Tanshinone IIA (C₁₉H₁₈O₃, Tan IIA) is a lipophilic diterpene isolated from Salvia miltiorrhiza Bunge, with reported anti-inflammatory activity. We tested whether Tan IIA could inhibit HSC activation.

Materials and Methods

The cell line of rat hepatic stellate cells (HSC-T6) was stimulated with lipopolysaccharide (LPS) (100 ng/ml). Cytotoxicity was assessed by MTT assay. HSC-T6 cells were pretreated with Tan IIA (1, 3 and 10 µM), then induced by LPS (100 ng/ml). NF-κB activity was evaluated by the luciferase reporter gene assay. Western blotting analysis was performed to measure NF-κB-p65, and phosphorylations of MAPKs (ERK, JNK, p38). Cell chemotaxis was assessed by both wound-healing assay and trans-well invasion assay. Quantitative real-time PCR was used to detect gene expression in HSC-T6 cells.

Results

All concentrations of drugs showed no cytotoxicity against HSC-T6 cells. LPS stimulated NF-κB luciferase activities, nuclear translocation of NF-κB-p65, and phosphorylations of ERK, JNK and p38, all of which were suppressed by Tan IIA. In addition, Tan IIA significantly inhibited LPS-induced HSCs chemotaxis, in both wound-healing and trans-well invasion assays. Moreover, Tan IIA attenuated LPS-induced mRNA expressions of CCL2, CCL3, CCL5, IL-1β, TNF-α, IL-6, ICAM-1, iNOS, and α-SMA in HSC-T6 cells.

Conclusion

Our results demonstrated that Tan IIA decreased LPS-induced HSC activation.     

Ribozymes against TGFbeta1 reverse character of activated hepatic stellate cells in vitro and inhibit liver fibrosis in rats

BACKGROUND/AIMS: Transforming growth factor beta (TGFbeta1) is considered the key mediator in the process of liver fibrosis. The purpose of this investigation was to evaluate the activity of ribozymes against TGFbeta1 in a cell-free system and activated hepatic stellate cells (HSCs), and antifibrotic effect in activated HSCs in vitro and in rats. METHODS: Three ribozymes targeting against TGFbeta1 mRNA were designed, and then cloned into the U1 snRNA expression cassette. The chimeric ribozymes were selected for the analysis of their performances in activated HSCs through the detection of their cleavage activities in a cell-free system. After ribozyme-encoding plasmids had been transfected into HSC-T6 cells, the effects of ribozymes on activated HSCs were evaluated through the analysis of proliferation, activation and collagen deposition of HSC-T6. The adenoviral vector expressing the ribozymes was constructed, and then delivered into rat models of hepatic fibrosis induced by carbon tetrachloride. RESULTS: TGFbeta1 expression was efficiently down-regulated in activated HSCs by U1 snRNA chimeric ribozymes which possessed perfect cleavage activity in a cell-free system. Further studies demonstrated that U1 snRNA chimeric ribozymes inhibited the synthesis of collagen I, reduced deposition of collagen I, suppressed BrdU incorporation, but had no effect on desmin and alpha-SMA expression in transfected HSC-T6 cells. Histological analysis demonstrated that the adenoviral vector expressing ribozyme (Rz803) could alleviate fibrotic pathology in rats treated with carbon tetrachloride. CONCLUSIONS: The anti-TGFbeta1 ribozymes could reverse the character of activated HSCs in vitro and improve fibrotic pathology in vivo. It indicated that TGFbeta1 could be considered as a novel candidate for a therapeutic agent against hepatic fibrosis.     

FBXO31 modulates activation of hepatic stellate cells and liver fibrogenesis by promoting ubiquitination of Smad7

Liver fibrosis is a critical pathological process in the early stage of many liver diseases, including hepatic cirrhosis and liver cancer. However, the molecular mechanism is not fully revealed. In this study, we investigated the role of F-box protein 31 (FBXO31) in liver fibrosis. We found FBXO31 upregulated in carbon tetrachloride (CCl₄) induced liver fibrosis and in activated hepatic stellate cells, induced by transforming growth factor-β (TGF-β). The enforced expression of FBXO31 caused enhanced proliferation and increased expression of α-smooth muscle actin (α-SMA) and Col-1 in HSC-T6 cells. Conversely, suppression of FBXO31 resulted in inhibition of proliferation and decreased accumulation of α-SMA and Col-1 in HSC-T6 cells. In addition, upregulation of FBXO31 in HSC-T6 cells decreased accumulation of Smad7, the negative regulator of the TGF-β/smad signaling pathway, and suppression of the FBXO31 increased accumulation of Smad7. Immunofluorescence staining showed FBXO31 colocalized with Smad7 in HSC-T6 cells and in liver tissues of BALB/c mice treated with CCl₄. Immunoprecipitation demonstrated FBXO31 interacted with Smad7. Moreover, FBXO31 enhanced ubiquitination of Smad7. In conclusion, FBXO31 modulates activation of HSCs and liver fibrogenesis by promoting ubiquitination of Smad7.     

姜黄素诱导Nrf2核转位对脂多糖引起库普弗细胞分泌炎症细胞因子的影响

目的：研究姜黄素诱导大鼠Kupffer细胞Nrf2核转位对脂多糖（LPS）引起的炎症细胞因子分泌的影响。方法：分别用10μM、20μM和30μM干预Kupffer细胞8h,诱导Nrf2核转位水平;将Kupffer细胞随机分为对照组、LPS组和干预组,对照组正常培养未加姜黄素和LPS,LPS组用10μg／mL的LPS加入Kupffer细胞培养液共同培养2h;干预组用30μM姜黄素干预8h后,余处理同LPS组。Western blot检测Nrf2核转位水平,分光光度法检测细胞MDA、GSH水平,ELISA法检测上清液TNF-α和IL-6,放免法检测IL-1β。结果：①姜黄素诱导Kupffer细胞Nrf2核转位,核转位水平随浓度增加而增高。②LPS组MDA水平较对照组显著升高（P〈0．01）,干预组MDA水平较LPS组显著降低（P〈0．01）,仍显著高于对照组（P〈0．01）。LPS组GSH水平较对照组显著降低（P〈0．01）,干预组GSH水平较LPS组显著升高（P〈0．01）,仍显著低于对照组（P〈0．01）。③LPS组上清液TNF-α,IL-1β和IL-6显著高于对照组（P〈0．01）,干预组均显著低于模型组（P〈0．01）,但显著高于对照组（P〈0．01）。结论：姜黄素通过诱导Kupffer细胞Nrf2核转位,降低LPS诱导的氧化应激损伤,抑制Kupffer细胞分泌炎症细胞因子。     

Asiatic acid inhibits liver fibrosis by blocking TGF-beta/Smad signaling in vivo and in vitro

Liver fibrosis is a major cause of liver failure, but treatment remains ineffective. In the present study, we investigated the mechanisms and anti-hepatofibrotic activities of asiatic acid (AA) in a rat model of liver fibrosis induced by carbon tetrachloride (CCl(4)) and in vitro in TGF-beta1-stimulated rat hepatic stellate cell line (HSC-T6). Treatment with AA significantly attenuated CCl(4)-induced liver fibrosis and functional impairment in a dosage-dependent manner, including blockade of the activation of HSC as determined by inhibiting de novo alpha smooth muscle actin (a-SMA) and collagen matrix expression, and an increase in ALT and AST (all p<0.01). The hepatoprotective effects of AA on fibrosis were associated with upregulation of hepatic Smad7, an inhibitor of TGF-beta signaling, thereby blocking upregulation of TGF-beta1 and CTGF and the activation of TGF-beta/Smad signaling. The anti-fibrosis activity and mechanisms of AA were further detected in vitro in HSC-T6. Addition of AA significantly induced Smad7 expression by HSC-T6 cells, thereby inhibiting TGF-beta1-induced Smad2/3 activation, myofibroblast transformation, and collagen matrix expression in a dosage-dependent manner. In contrast, knockdown of Smad7 in HSC-T6 cells prevented AA-induced inhibition of HSC-T6 cell activation and fibrosis in response to TGF-beta1, revealing an essential role for Smad7 in AA-induced anti-fibrotic activities during liver fibrosis in vivo and in vitro. In conclusion, AA may be a novel therapeutic agent for liver fibrosis. Induction of Smad7-dependent inhibition of TGF-beta/Smad-mediated fibrogenesis may be a central mechanism by which AA protects liver from injury.     

结缔组织生长因子基因RNA干扰复制缺陷型腺病毒载体的构建及鉴定

目的：构建能介导结缔组织生长因子（CTGF）基因RNA干扰的复制缺陷型腺病毒表达载体。方法：以大鼠CTGF基因为靶序列,设计并合成含编码短发夹RNA序列的寡核苷酸,构建腺病毒穿梭质粒P-shuttle-CTGF,酶切及测序分析正确后,与腺病毒骨架质粒pAdEasy-1共转染AD-293细胞,进行病毒包装,得到腺病毒载体Ad．H1-CTGF,用该载体感染HSC-T6细胞,观察其对CTGF基因表达抑制的效果。结果：构建的腺病毒穿梭质粒p-shuttle-CTGF经酶切、测序分析证实正确;包装的病毒载体滴度为4×1010PFU／mL,感染HSC-T6细胞后,Western印迹证实CTGF表达显著减少。结论：构建的腺病毒载体Ad．H1-CTGF可有效抑制HSC-T6中CTGF的表达,为抗纤维化研究提供了有力的工具。     

Novel matrine derivative MD-1 attenuates hepatic fibrosis by inhibiting EGFR activation of hepatic stellate cells

Matrine (MT), the effective component of Sophora flavescens Ait, has been shown to have anti-inflammation, immune-suppressive, anti-tumor, and anti-hepatic fibrosis activities. However, the pharmacological effects of MT still need to be strengthened due to its relatively low efficacy and short half-life. In the present study, we report a more effective thio derivative of MT, MD-1, and its inhibitory effects on the activation of hepatic stellate cells (HSCs) in both cell culture and animal models. Cytological experiments showed that MD-1 can inhibit the proliferation of HSC-T6 cells with a half-maximal inhibitory concentration (IC50) of 62 μmol/L. In addition, MD-1 more strongly inhibits the migration of HSC-T6 cells compared to MT and can more effectively induce G0/G1 arrest and apoptosis. Investigating the biological mechanisms underlying anti-hepatic fibrosis in the presence of MD-1, we found that MD-1 can bind the epidermal growth factor receptor (EGFR) on the surface of HSC-T6 cells, which can further inhibit the phosphorylation of EGFR and its downstream protein kinase B (Akt), resulting in decreased expression of cyclin D1 and eventual inhibition of the activation of HSC-T6 cells. Furthermore, in rats with dimethylnitrosamine (DMN)-induced hepatic fibrosis, MD-1 slowed the development and progression of hepatic fibrosis, protecting hepatic parenchymal cells and improving hepatic functions. Therefore, MD-1 is a potential drug for anti-hepatic fibrosis.     

Methyl helicterate inhibits hepatic stellate cell activation through downregulating the ERK1/2 signaling pathway

The present study was to investigate the inhibitory effect of methyl helicterate (MH) on hepatic stellate cells (HSC-T6), primarily elucidating the underlying mechanism of MH against liver fibrosis. HSC-T6 cells were activated by platelet-derived growth factor (PDGF) stimulation, and then the effects of MH on cell viability, cytomembrane integrity, colony, migration, apoptosis, and cell cycle were detected. Moreover, the regulative mechanism of MH on HSCs was investigated by detecting the activation of the extracellular signal-regulated kinase (ERK1/2) signaling pathway. The results showed that MH significantly inhibited HSC-T6 cell viability and proliferation in a concentration-dependent manner. It notably promoted the release of lactate dehydrogenase, destroying cell membrane integrity. MH also markedly inhibited HSC-T6 cell clonogenicity and migration. Moreover, MH treatment significantly induced cell apoptosis and arrested cell cycle at the G2 phase. The further study showed that MH inhibited the expression of ERK1, ERK2, c-fos, c-myc, and Ets-1, blocking the ERK1/2 pathway. In conclusion, this study demonstrates that MH significantly inhibits HSC activation and promotes cell apoptosis via downregulation of the ERK1/2 signaling pathway.     

Lipopolysaccharide inhibits GPR120 expression in macrophages via Toll‐like receptor 4 and p38 MAPK activation

Free fatty acid receptor G protein‐coupled receptor 120 (GPR120) is highly expressed in macrophages and was reported to inhibit lipopolysaccharide (LPS)‐stimulated cytokine expression. Under inflammation, macrophages exhibit striking functional changes, but changes in GPR120 expression and signaling are not known. In this study, the effects of LPS treatment on macrophage GPR120 expression and activation were investigated. The results showed that LPS inhibited GPR120 expression in mouse macrophage cell line Ana‐1 cells. Moreover, LPS treatment inhibited GPR120 expression in mouse alveolar macrophages both in vitro and in vivo. The inhibitory effect of LPS on GPR120 expression was blocked by Toll‐like receptor 4 (TLR4) inhibitor TAK242 and p38 mitogen‐activated protein kinase inhibitor LY222820, but not by ERK1/2 inhibitor U0126 and c‐Jun N‐terminal kinase inhibitor SP600125. LPS‐induced inhibition of GPR120 expression was not attenuated by GPR120 agonists TUG891 and GW9508. TUG891 inhibited the phagocytosis of alveolar macrophages, and LPS treatment counteracted the effects of TUG891 on phagocytosis. These results indicate that pretreatment with LPS inhibits GPR120 expression and activation in macrophages. It is suggested that LPS‐induced inhibition of GPR120 expression is a reaction enhancing the LPS‐induced pro‐inflammatory response of macrophages.