大黄素对Cx32组成的细胞缝隙连接通讯功能的影响

目的在转染并稳定表达Cx32的Hela细胞上,观察大黄素对Cx32的GJIC以及Cx32蛋白表达水平的影响。方法采用SRB法检测不同浓度大黄素对Hela细胞的毒性;用细胞接种荧光示踪法("parachute"dye-couplinga ssay)观察不同浓度大黄素对GJIC的影响;用western blot法研究大黄素在影响GJIC功能浓度范围内对Cx32蛋白表达的影响。结果大黄素在0~1μmol/L浓度时对Hela细胞无毒性作用;大黄素(24~600nmol/L)预处理4h,能浓度依赖性地增强GJIC及Cx32蛋白表达量。结论大黄素能够增强Cx32的细胞GJIC;此增强作用可能与其增加Cx32蛋白表达水平有关。     

缝隙连接蛋白43对人非小细胞肺癌HCC827细胞吉非替尼获得性耐药机制的初步研究

目的探讨缝隙连接蛋白43(connexin 43,Cx43)与非小细胞肺癌(NSCLC)细胞产生吉非替尼(Gefitinib)获得性耐药的关系。方法在Gefitinib敏感细胞株HCC827上,通过逐步递增Gefitinib浓度诱导获得Gefitinib耐药细胞株HCC827 GR;MTT法检测Gefitinib对HCC827/GR细胞的IC_(50);RT-PCR检测Cx43的mRNA水平;Western blot检测Cx43和磷酸化Akt(p-Akt)的蛋白水平;parachute荧光示踪法检测细胞缝隙连接功能(gap junction intercellular communication,GJIC);免疫荧光技术检测Cx43的细胞定位。结果Gefitinib作用于HCC827和HCC827 GR的IC_(50)分别为(0.07±0.019)μmol·L~(-1)、(10.84±0.021)μmol·L~(-1)(P<0.01);HCC827 GR中Cx43的mRNA和蛋白水平较HCC827明显降低(P<0.05),但p-Akt蛋白水平明显升高(P<0.05)。在HCC827 GR细胞上加PI3K的特异性抑制剂LY294002(25μmol·L~(-1),24 h)后,p-Akt蛋白水平明显下降(P<0.01),且Cx43的蛋白水平明显升高(P<0.01)。HCC827及HCC827 GR均未检测到GJIC,用GJIC增强剂RA(retinoic acid)处理(10μmol·L~(-1),24 h)上述细胞,亦未检测到荧光传递,免疫荧光结果显示Cx43表达在细胞胞质。结论胞质中Cx43的下调可能促进NSCLC细胞对Gefitinib的获得性耐药,其机制可能与Cx43非GJIC依赖的PI3K/Akt信号通路激活有关。     

赖氨匹林增强Cx32/Cx26组成的Hela细胞缝隙连接功能

目的 体外观察赖氨匹林对转染并稳定表达连接蛋白32/26 （Cx32/Cx26）的Hela细胞缝隙连接通讯（GJIC）功能和Cx32/Cx26蛋白表达水平的影响.方法 不同浓度（0、1、5、10 mmol·L^-1）赖氨匹林作用于人宫颈癌Hela细胞24 h后,以划痕标记/染料示踪技术（SL/DT）检测赖氨匹林作用Hela细胞48 h后荧光黄在细胞之间传递的距离来评价其对缝隙连接（GJ）功能的影响;Western blot方法检测赖氨匹林对Cx32/Cx26蛋白表达的影响.结果 SL/DT检测显示赖氨匹林具有上调GJ功能的作用;Western blot显示赖氨匹林增加Cx32/Cx26蛋白表达水平.结论 赖氨匹林抑制转染并稳定表达Cx32/Cx26的Hela细胞的增殖、上调GJ功能且这种作用可能与其增加Cx32/Cx26蛋白表达水平有关.     

细胞缝隙连接对miR-124抗肿瘤作用的影响和机制研究

目的探讨不同连接蛋白(connexin,Cx)组成的缝隙连接(gap junction,GJ)对miR-124抗肿瘤作用的影响及机制。方法在稳定转染表达Cx26或Cx32的Hela细胞(Hela26、Hela32),以及稳定转染shRNA-Cx43的人胶质瘤U87细胞(U87~(shRNA-Cx43))中,应用Western blot和荧光示踪实验分别测定Cx表达和GJ功能;集落形成实验检测miR-124对细胞增殖影响;膜片钳检测Cy3荧光标记的miR-124在细胞间的传递。结果多西环素可诱导Hela26和Hela32细胞上Cx表达和GJ形成;miR-124抑制Hela细胞增殖,但在有GJ(Dox诱导)和无GJ形成(无Dox诱导)条件下统计学上无明显差异。相较于U87~(shRNA-NC),U87~(shRNA-Cx43)细胞中Cx43表达、GJ功能及miR-124的增殖抑制作用均明显降低;显微镜下可见导入到"供体细胞"中的荧光miRNA逐渐布满整个细胞并传递到相邻非"导入"细胞内。结论 GJ可影响miR-124的抗肿瘤作用,但具有Cx异质性。相较Cx26或Cx32,Cx43组成的GJ可调控miR-124的抗肿瘤作用,这可能与该GJ通道对miR-124的传递作用较强有关。     

慢病毒靶向干扰Cx26抑制人高转移性肝癌HCCLM3细胞增殖及迁移

目的探讨缝隙连接蛋白26(connexin 26,Cx26)对人高转移性肝癌HCCLM3细胞增殖、凋亡、迁移能力的影响。方法构建Cx26干扰慢病毒载体感染HCCLM3细胞,用嘌呤霉素筛选稳定干扰Cx26表达的靶细胞,通过Realtime PCR和Western blot鉴定Cx26的mRNA和蛋白表达情况;用"parachute"荧光示踪法检测细胞缝隙连接(gap junction,GJ)功能;用MTT法、流式细胞术、Transwell迁移实验分别检测干扰Cx26对HCCLM3细胞增殖、凋亡、迁移能力的影响。结果 LV-Cx26组的Cx26 mRNA和蛋白表达明显低于LV-NC组和野生组细胞(P<0.01),并且LV-Cx26组的GJ功能也较LV-NC组和野生组明显减弱(P<0.01)。干扰Cx26可明显抑制HCCLM3细胞增殖(P<0.01),促进HCCLM3细胞凋亡(P<0.01),降低其体外迁移能力(P<0.01)。结论慢病毒靶向干扰Cx26表达可明显减弱其GJ功能,并抑制高转移性肝癌HCCLM3细胞增殖、迁移能力,促进凋亡,降低其恶性生物学特性。     

慢病毒介导稳定高表达Cx32的Huh7细胞系建立及其对细胞增殖的影响

目的构建LV5-h Cx32慢病毒表达载体,获得稳定高表达人缝隙连接蛋白32(connexin32,Cx32)的Huh7人肝癌细胞系,并研究Cx32对Huh7细胞增殖的影响。方法采用全基因合成法并经PCR扩增得到Cx32基因序列,将所得目的片段克隆到LV5-GFP载体上,获得重组慢病毒质粒LV5-GFP-h Cx32,经酶切鉴定及DNA测序鉴定后,与慢病毒包装质粒系统共转染293T细胞中,包装成重组慢病毒颗粒,经荧光显微镜测定重组慢病毒滴度。将慢病毒载体LV5-h Cx32和LV5-NC感染Huh7细胞,嘌呤霉素筛选出细胞阳性克隆并扩大培养。qRT-PCR、Western blot和免疫荧光法分析Cx32的表达及定位;细胞接种荧光示踪法检测细胞缝隙连接(gap junction,GJ)功能;MTT法及克隆形成实验观察细胞增殖能力的变化。结果双酶切及测序结果表明LV5-GFPh Cx32慢病毒载体构建成功,经293T细胞包装后,成功获得病毒滴度为3×10¹¹TU·L^-1的重组慢病毒LV5-GFP-h Cx32,慢病毒瞬时感染后的Huh7细胞中Cx32 mRNA和蛋白表达水平明显增多,筛选后建立的稳定转染细胞系中Cx32也稳定高表达,并且部分表达于细胞膜,形成有功能性的GJ。过表达Cx32的Huh7细胞增殖能力减弱(P<0.05)。结论成功构建Cx32基因过表达慢病毒载体,该载体能够稳定感染Huh7细胞,使外源基因Cx32过表达并抑制细胞的增殖能力。     

二甲双胍对高糖培养H9c2细胞Connexin43表达的影响

目的研究二甲双胍(metformin,Met)对高糖培养下的H9c2细胞缝隙连接蛋白43(connexin43,Cx43)表达的影响及其机制。方法高糖培养的大鼠H9c2心肌细胞分别加入3和5μmol·L-1的两种不同浓度的二甲双胍继续培养24 h。MTT实验检测H9c2细胞活力;LDH释放实验检测细胞毒力;细胞免疫荧光实验检测Cx43的表达和分布;荧光法检测细胞内活性氧(ROS)水平;Western blot检测Cx43、pAMPK、AMPK和GAPDH的表达。结果 Met能增加H9c2细胞活力,降低细胞内ROS水平,对LDH释放差异无显著性;Met使AMPK磷酸化水平明显升高,增加心肌Cx43表达,改善Cx43的分布。结论 Met可能通过激活AMPK途径,增加心肌细胞Cx43的表达和减少细胞内ROS的产生,进而发挥心血管的保护效应。     

TRPV1/SIRT1介导吴茱萸次碱抗AngⅡ诱导的血管平滑肌细胞衰老

目的探讨吴茱萸次碱(rutaecarpine,Rut)对长寿蛋白SIRT1表达及AngⅡ诱导的血管平滑肌细胞(vascular smooth muscle cells,VSMCs)衰老的影响。方法采用AngⅡ(1μmol·L^-1)孵育大鼠胸主动脉平滑肌细胞72 h,预先加入不同浓度的Rut(0.3、1、3μmol·L^-1),采用TRPV1拮抗剂CAPZ(10μmol·L^-1)和AMPK抑制剂Compound C(1μmol·L^-1)探讨TRPV1/AMPK是否介导Rut的保护效应。SA-β-Gal测定衰老细胞数目,DCFH-DA法测定细胞ROS水平。划痕愈合结合Transwell检测VSMCs迁移。Western blot检测VSMCs中长寿蛋白SIRT1和衰老相关蛋白p53、p21的表达以及p-AMPK水平。结果Rut明显地抑制AngⅡ诱导的VSMCs衰老和ROS生成,并抑制VSMCs迁移。预先给予TRPV1拮抗剂可取消Rut这一保护作用。AngⅡ可降低SIRT1的表达,给予Rut可剂量依赖性地恢复SIRT1的表达,且下调其下游衰老相关蛋白p53和p21的表达。AngⅡ可抑制p-AMPK,加入Rut能恢复p-AMPK水平。CAPZ和Compound C可消除Rut升高SIRT1表达的效应。结论Rut可上调SIRT1表达,抑制AngⅡ诱导的VSMCs衰老和迁移,其机制可能激活TRPV1/AMPK信号途径。     

漆黄素通过缝隙连接影响顺铂细胞毒性

目的体外观察漆黄素对顺铂细胞毒性作用影响及其机制。方法 CCK-8法观察不同浓度漆黄素对人胶质瘤U87细胞的毒性;用细胞接种荧光示踪法测定不同浓度漆黄素对U87细胞缝隙连接(GJ)功能的影响;标准细胞集落形成分析法观察顺铂的毒性及漆黄素对顺铂毒性的影响;用Western blot法研究漆黄素在影响GJIC(GJ intercellular communication)功能浓度范围内对Cx43表达的影响。结果 CCK-8法显示漆黄素在小于1μmol·L-1的浓度范围内无细胞毒性;细胞接种荧光示踪法显示漆黄素浓度越高,U87细胞GJ通讯的荧光传递功能越强;标准细胞集落形成分析法显示,20μmol·L-1顺铂能够抑制U87细胞的集落形成,而且在有GJ形成的细胞顺铂对细胞集落形成的抑制作用显著高于无GJ形成的细胞;Western blot结果显示漆黄素对Cx43蛋白表达量无明显影响。结论漆黄素可以增强顺铂的细胞毒性,该作用可能与漆黄素增强U87细胞的GJ通讯功能有关,与Cx43蛋白表达水平变化无关。     

丁苯酞对于星型胶质细胞炎症反应的保护作用及缝隙连接蛋白Cx43表达的影响

目的：研究丁苯酞(NBP)对于脂多糖(LPS)诱导的星型胶质细胞炎症反应的抑制作用和机制,同时观察其对于缝隙连接蛋白Cx43表达的影响。方法：星型胶质细胞(Astroglia,Ast)采用梯度浓度的NBP处理,1μg/ml的LPS诱导炎症反应。试剂盒检测乳酸脱氢酶(LDH)漏出量,CCK-8法检测细胞存活率,Griess法检测NO的释放水平,Elisa法检测培养基中炎症因子IL-1β、IL-6及TNF-α的表达水平。蛋白印迹法Western-Blot法检测p65,p-IκB,Cx43的表达。免疫荧光染色法检测Cx43的分布。验证Cx43与星型胶质细胞炎症损伤的关系：siRNA沉默Ast中Cx43的表达,LPS诱导炎症发生后,检测Ast的炎症因子释放以及细胞存活水平。结果：NBP可以降低Ast细胞中LDH的漏出,提高细胞存活率,抑制炎症因子的释放,同时抑制细胞中p65、p-IκB的表达。NBP同时可以抑制Ast中Cx43的表达。siRNA沉默Cx43后,Ast的炎症反应得到抑制。结论：丁苯酞可以抑制LPS诱导的Ast炎症反应,而Cx43与炎症反应的发生有关。丁苯酞抑制Ast炎症反应与抑制Cx43的表达有关。     

Silver nanoparticles up-regulate Connexin43 expression and increase gap junctional intercellular communication in human lung adenocarcinoma cell line A549

Abstract

Silver nanoparticles (Ag NPs) are increasingly being used in wound dressings, medical settings, and various household products due to their unique properties and antimicrobial activity. Despite the widespread use of Ag NP products, the molecular mechanisms underlying the biological effects of Ag NPs remain unclear. Gap junctional intercellular communication (GJIC), formed by the connexin protein family, plays a critical role in the maintenance of tissue and organ homeostasis. This study was undertaken to investigate the effects of well characterized, PVP-coated Ag NPs (69 ± 3 nm) and silver nitrate on GJIC and connexin43 (Cx43) expression in human lung adenocarcinoma cell line A549. Our results showed that Ag NPs increased GJIC in A549 cells as assayed by dye transfer method. Western blot analysis showed that incubation of cells with Ag NPs significantly increased the expression of Cx43 protein. In addition, Ag NPs up-regulated expression of Cx43 mRNA in a dose-dependent manner. Silver nitrate failed to increase GJIC and the expression of Cx43 protein. It, however, increased Cx43 mRNA expression in A549 cells. Taken together, our results provide the first evidence that Ag NPs induced the increase of GJIC activity in A549 cells through up-regulation of Cx43 protein, suggesting that Cx43 and GJIC may be one of the targets for Ag NPs biological effects.     

Cadmium decreases gap junctional intercellular communication in mouse liver.

Cadmium (Cd) is an environmental pollutant of increasing importance, due to industrialization, smoking, and the lack of effective therapy for Cd poisoning. The general population is exposed to Cd principally through food and water. The metal accumulates slowly in the liver and kidney, the target organs of acute and chronic Cd toxicity, respectively. We showed recently that liver is also a target organ for chronic Cd toxicity. Gap junctional intercellular communication (GJIC) is a means of maintaining cellular homeostasis in multicellular organisms. It involves the transfer of small, water-soluble molecules through intercellular channels (gap junctions), composed of proteins called connexins. The major connexins of liver (hepatocytes) are connexin 32 (Cx32) and connexin 26 (Cx26). Cd disrupts cellular homeostasis in the liver through its induction of necrosis, apoptosis, and cellular proliferation. It is to be expected, therefore, that Cd must exert some effect on GJIC. This study investigates Cd-induced alterations in GJIC, Cx32, and Cx26 expression, and in cytoskeletal actin, and relates the changes to apoptosis and cell proliferation induced by Cd in vivo. Mice were injected ip with 30 micromol Cd/kg, and were observed for up to 48 h. Other groups of mice were injected with 5-60 micromol Cd/kg and observed for 9 h. Blood and liver were harvested and used for analysis of GJIC, connexin expression, cytoskeletal actin, serum enzymes, and liver pathology. Cd produced a time- and dose-dependent inhibition of GJIC in liver, along with parallel decreases in the expression of Cx32 and Cx26. Cd also produced disruption and loss of cytoskeletal actin in liver in a time- and dose-dependent manner. These observations are discussed in relation to the toxicity of Cd, and possible mechanisms of induction of the GJIC-related alterations are presented.     

3,4,5,6-Tetrahydroxyxanthone preserves intercellular communication by reduction of the endogenous nitric oxide synthase inhibitor level

To observe the direct effects of 3,4,5,6-tetrahydroxyxanthone on connexin43 (Cx43) expression in cultured endothelial cells, cells were treated with lysophosphatidylcholine (LPC, 10 mg/l) for 24 h in the presence or absence of different concentrations of 3,4,5,6-tetrahydroxyxanthone (1, 3, or 10 μmol l^? 1). The reactive oxygen species (ROS) production, cell viability, asymmetric dimethylarginine (ADMA) levels, and Cx43 expression were detected. 3,4,5,6-Tetrahydroxyxanthone significantly inhibited the increase in ROS production and ADMA level, increased cell viability and up-regulated Cx43 mRNA and protein expression induced by LPC. 3,4,5,6-Tetrahydroxyxanthone has protective effect in LPC-induced atherosclerotic lesions, which is at least partly related to the reduction of ADMA level and downregulation of Cx43 expression.     

Connexin 40-formed GJIC increases the phototoxicity of photodynamic therapy through ROS-and calcium-mediated pathways

OBJECTIVE To explore the effect of connexin(Cx)40-formed gap junctional intercellular communication(GJIC)on Photofrin-photodynamic therapy(PDT)phototoxicity in Cx40-transfected He La cells and its potential mechanisms.METHODS He La cell line stably transfected to express Cx40 was seeded at high and low cell density,respectively,to assess in vitro photosensitivity using CCK8 assay.Western blot assay was performed to detect the expression of Cx40.The intracellular ROS and Ca~(2+) concentrations were determined using flow cytometer.4-HNE and ceramide were measured using ELISA assay.RESULTS Cx40-composed GJ formation at high density enhances the phototoxicity of PhotofrinPDT.When the Cx40 is not expressed or Cx40 channels are blocked,the phototoxicity in high-density cultures substantially reduces,indicating that the enhanced PDT phototoxicity at high density is mediated by Cx40-composed GJIC.The GJIC-mediated increase in PDT phototoxicity was associated with ROS and calcium-mediated stress signaling pathways.CONCLUSION The work uniquely presents the ability of Cx40-composed GJIC to enhance the sensitivity of malignant cells to PDT,and indicates that maintenance or increase of Cx40-formed GJIC may be a profitable strategy towards the enhancement of PDT therapeutic efficiency.     

Effects of bisphenol A on gap junctions in HaCaT cells as mediated by the estrogen receptor pathway

Bisphenol A (BPA) is widely used as the raw material for the production of plastics and paper products. People can be exposed to BPA through dermal contact, particularly for cashiers in contact with thermal paper every day. BPA is a known endocrine disruptor that has been shown to be carcinogenic. Many tumors show weak gap junctional intercellular communication (GJIC) function. The aim of this study was to investigate the effects and possible mechanisms of BPA's action on GJIC of human HaCaT skin cells. The results showed that BPA increased cell proliferation rates, prolonged GJIC photobleaching fluorescence recovery times and reduced overall fluorescence recovery rates at 0.01, 0.1 and 1 μm . BPA downregulated connexin (Cx)26 mRNA level at 0.1 μm . Estrogen receptor (ER) antagonist ICI 182 780 at 5 nm partially blocked the above effects of BPA indicating involvement of the ER pathway with BPA exposure. However, BPA did not influence Cx43 mRNA and protein levels. Our immunofluorescence data showed that Cx26 was expressed in the cytoplasm and plasma membrane, and was involved in the formation of gap junctions between adjacent cells, while Cx43 was expressed only in the cytoplasm. Therefore, our data indicate that Cx26 gap junctions may be involved in the GJIC inhibition caused by BPA. In conclusion, our results indicate that BPA can promote human skin cell proliferation, inhibit skin cell GJIC function but not formation and downregulate Cx26 mRNA levels partially through the ER pathway. We hypothesize that BPA can exhibit carcinogenicity by inhibiting GJIC.     

3,4,5,6-Tetrahydroxyxanthone preserves intercellular communication by reduction of the endogenous nitric oxide synthase inhibitor level

To observe the direct effects of 3,4,5,6-tetrahydroxyxanthone on connexin43 (Cx43) expression in cultured endothelial cells, cells were treated with lysophosphatidylcholine (LPC, 10?mg/l) for 24?h in the presence or absence of different concentrations of 3,4,5,6-tetrahydroxyxanthone (1, 3, or 10?μmol?l(-?1)). The reactive oxygen species (ROS) production, cell viability, asymmetric dimethylarginine (ADMA) levels, and Cx43 expression were detected. 3,4,5,6-Tetrahydroxyxanthone significantly inhibited the increase in ROS production and ADMA level, increased cell viability and up-regulated Cx43 mRNA and protein expression induced by LPC. 3,4,5,6-Tetrahydroxyxanthone has protective effect in LPC-induced atherosclerotic lesions, which is at least partly related to the reduction of ADMA level and downregulation of Cx43 expression.