RNA干扰抑制血管平滑肌细胞缝隙连接Cx43介导的细胞间通讯

RNA干扰技术的效应分子是小分子短链RNA（siRNA）。本实验拟通过转染Cx43特异性siRNA检测平滑肌细胞Cx43基因表达和细胞间通讯（GJIC）功能。探讨RNA干扰技术在血管平滑肌细胞缝隙连接功能研究中的应用。     

TGF-β1在大鼠睾丸支持细胞的作用及对紧密连接的影响

目的:探讨TGF-β1在大鼠睾丸支持细胞增殖和凋亡中的作用以及对紧密连接相关蛋白基因表达的影响。方法:体外分离和培养大鼠睾丸支持细胞,分空白对照组、TGF-β1受体阻滞剂组、TGF-β1刺激组和TGF-β1+受体阻滞剂组共4组。CCK-8检测细胞增殖;流式细胞术检测细胞凋亡;建立支持细胞原代双室培养模型,应用跨上皮电阻测定法(TER)检测单层细胞两侧跨细胞电阻值;RT-PCR和Western印迹检测支持细胞闭合蛋白(Occludin)、闭锁小带蛋白1(ZO-1)和紧密连接蛋白Ⅱ(ClaudinⅡ)的相对表达量。结果:各组细胞增殖组间差异有统计学意义(F=5.05,P0.05),TGF-β1刺激组与空白对照组相比细胞增殖率增加(P0.05),而TGF-β1+受体阻滞剂组与TGF-β1刺激组相比细胞增殖率降低(P0.05)。各组细胞凋亡率组间差异无统计学意义(F=1.13,P0.05);各组细胞间TER差异有统计学意义(F=38.99,P0.01),与空白对照组比较TGF-β1刺激组TER降低(P0.01),与TGF-β1刺激组比较,TGF-β1+受体阻滞剂组和TGF-β1受体阻滞剂组细胞TER升高(P均0.01);各组支持细胞中ZO-1、ClaudinⅡmRNA及蛋白在各组中的表达量差异均无统计学意义(F_(mRNA)=0.49,0.93,P均0.05;F_(蛋白)=0.28,1.31,P均0.05),而Occludin mRNA及蛋白在各组中的表达量差异均有统计学意义(F_(mRNA)=6.86,F_(蛋白)=6.87,P均0.05);与空白对照组相比,TGF-β1刺激组Occludin mRNA及蛋白表达明显降低(P均0.01),而加入受体阻滞剂后,Occludin mRNA及蛋白表达明显回升(P均0.05)。结论:TGF-β1对睾丸支持细胞的增殖有促进作用,并能通过调节Occludin蛋白的表达而影响大鼠支持细胞间的紧密连接。     

18β-GA对逼尿肌不稳定缝隙连接介导细胞间通讯功能影响

缝隙连接（GJ）是相邻细胞间跨膜离子及低分子通道，逼尿肌缝隙连接介导细胞间通讯（GJIC）功能在DI发病机制中具有重要意义。本研究旨在利用激光扫描共聚焦显微镜（删）及荧光漂白后恢复技术（FRAP）观察缝隙连接阻滞剂18阻GA对培养大鼠DI细胞GJIC功能的影响，为采用阻断细胞间兴奋传递来治疗DI提供依据。     

病理性瘢痕和正常皮肤成纤维细胞缝隙连接介导的细胞间通讯

目的 研究和比较不同来源的成纤维细胞缝隙连接介导的细胞间通讯的差异。方法 取手术切除的正常皮肤、增生性瘢痕、瘢痕疙瘩组织各6例,通过细胞培养6-8代后,应用粘附式细胞仪检测及比较各种来源的细胞缝隙连接介导的细胞间通讯。结果 正常皮肤成纤维细胞的细胞间通讯正常,增生性瘢痕成纤维细胞的细胞间通讯受到抑制,瘢痕疙瘩成纤维细胞的细胞间通讯被阻断。结论 细胞间通讯被证明与细胞生长的接触抑制及细胞的浸润性生长密切相关。细胞间通讯被阻断是瘢痕疙瘩呈“蟹足样”浸润性生长的细胞生物学机理之一。     

间隙连接蛋白43表达改变对肾小管上皮细胞转分化的影响

目的 研究肾小管上皮细胞-肌成纤维细胞转分化（TEMT）过程中间隙连接蛋白43（connexin 43）表达和细胞间通讯功能的变化,以及上调connexin 43水平对TEMT的影响。方法 用转化生长因子（TGF）β1刺激人肾小管上皮细胞系（HKC）,检测connexin 43、上皮细胞标志物E-钙黏蛋白（E-cadherin）和肌成纤维细胞标志物α-SMA、vimentin的表达。用激光共聚焦显微镜荧光漂白恢复（FRAP）技术检测HKC细胞间通讯功能。通过pLNCX2- connexin 43病毒质粒转染HKC上调connexin 43的表达,检测以上各指标的变化,观察对TEMT的影响。结果 HKC经TGF-β1刺激后．其α-SMA和vimentin mRNA和蛋白质表达增强,而E-cadherin和connexin 43表达下降（P＜0．05）,细胞间通讯功能降低（P＜0．05）。connexin 43高表达后,TEMT程度明显减轻。结论 上调肾小管上皮细胞间通讯功能可部分减轻TEMT程度。     

敌敌畏对大鼠睾丸Leydig细胞凋亡的影响

目的:观察敌敌畏对子代雄性大鼠睾丸Leydig细胞凋亡的影响,探讨Leydig细胞变化在泌尿生殖系统畸形发病机制中的意义。方法:将21只孕SD大鼠随机分为对照组和敌敌畏各剂量组,在孕12～17 d期间,对照组每天分别给予灌喂玉米油1.0 ml;敌敌畏各剂量组每天分别给予敌敌畏1、4、8、16、20、24 mg/kg。待孕鼠分娩完毕,每组随机选取5只新生雄性仔鼠睾丸标本行HE染色、caspase-3免疫组化染色和DAPI荧光染色,将余下的雄性仔鼠饲养至90 d后再随机选取5只成年雄性仔鼠睾丸标本行HE染色、caspase-3免疫组化染色和DAPI荧光染色。结果:玉米油对照组雄性仔鼠睾丸组织caspase-3染色阳性的Leydig细胞数量和DAPI标记的Leydig细胞的总分值与敌敌畏1 mg/(kg.d)组比较无统计学意义(P>0.05),与敌敌畏其余剂量组比较有统计学差异(P<0.05),敌敌畏可使雄性仔鼠睾丸caspase-3染色阳性的Leydig细胞数量和DAPI标记的Leydig细胞的总分值增加,并与敌敌畏存在剂量依赖关系。结论:孕期染毒敌敌畏可使雄性仔鼠睾丸Leydig细胞的凋亡增加,这可能影响到Leydig细胞的数量,使胚胎期胎睾产生睾酮的功能受到干扰,从而使泌尿生殖系统的发育受到影响。     

不稳定逼尿肌中Cx43的表达及其对细胞间通讯的影响

目的研究Cx43在不稳定逼尿肌细胞中的表达及其对不稳定逼尿肌细胞间缝隙连接通讯的影响,探讨Cx43与逼尿肌不稳定（DI）的关系。方法采用Western blot法检测正常及不稳定逼尿肌细胞中Cx43蛋白表达。构建Cx43反义真核表达载体,脂质体介导转染体外培养不稳定逼尿肌细胞（转染组）,空载体做对照转染（空载组）。利用划痕标记荧光染料示踪（SLDT）技术观察Cx43表达降低后不稳定逼尿肌细胞间缝隙连接通讯改变。结果不稳定逼尿肌细胞中Cx43表达显著增高（P〈0．01）,转染反义Cx43组不稳定逼尿肌细胞间缝隙连接通讯较空载组明显减弱（P〈0．05）。结论抑制Cx43表达可明显降低不稳定逼尿肌细胞间缝隙连接通讯功能,Cx43表达增高可能是不稳定逼尿肌发生的重要原因。     

淫羊藿苷对转化生长因子-β1诱导的大鼠睾丸间质细胞损伤的保护作用

目的:研究淫羊藿苷(Icariin)对转化生长因子-β1(TGF-β1)诱导的大鼠睾丸间质细胞损伤的保护作用。方法:利用4-甲偶氮唑蓝法筛选Icariin对TGF-β1诱导的间质细胞损伤保护作用的最适浓度,用放射免疫法和3H释放实验检测Icariin作用前后损伤的间质细胞中雌激素(E2)含量和芳香化酶P450arom活性,采用荧光漂白后恢复实验检测Icariin对损伤的间质细胞间缝隙连接通讯(GJIC)功能的影响。结果:不同浓度Icariin均可提高TGF-β1作用后睾丸间质细胞的活细胞率,其中,20μg/ml时即可发挥作用,而160μg/ml时达到最佳;用160μg/ml浓度Icariin干预TGF-β1损伤的睾丸间质细胞后,间质细胞中E2的生成和芳香化酶活性显著增加(P0.01),且间质细胞间的荧光恢复率也明显提高(P0.01)。结论:Icariin可通过增加E2合成有效阻止TGF-β1对间质细胞的损伤,这种影响可能通过部分上调雌激素合成的关键酶P450arom活性实现;且Icariin还具有改善间质细胞间GJIC功能的作用。     

缝隙连接蛋白43在骨骼发育和塑形中的作用

骨骼的发育和塑形过程要求成骨细胞、骨细胞及破骨细胞在接受胞外刺激时能发挥高度协调统一的生物学功能.相邻细胞间缝隙连接蛋白(Cx)构成的缝隙连接介导细胞间信号通路,使骨骼细胞在接受胞外刺激后产生的信号分子在相关细胞中迅速传递,从而使调节骨骼发育、塑形的相关细胞群形成一功能整体.Cx43是骨骼组织中最重要的连接蛋白,与骨骼发育、塑形和再塑形密切相关,它的基因突变、表达异常可导致眼-牙-指(趾)综合征或其他骨骼发育畸形.Cx43在各种理化因素对骨骼细胞发挥生物学效应过程中均扮演重要角色,这与相关信号通路活化密切相关.     

大鼠睾丸Leydig细胞体外增殖研究

目的:探讨通过优化细胞培养体系,实现Leydig细胞的体外增殖培养。方法:联合应用胶原酶消化、不锈钢滤网过滤及差速贴壁法获得3周龄雄性Wistar大鼠睾丸Leydig细胞,贴壁细胞以DMEM/F12培养液及优化培养体系培养,MTT法、细胞计数法检测培养细胞的增殖能力;分别对原代培养2h、4d细胞进行3β-HSD免疫化学染色及流式细胞术分析,检测细胞成分,同时检测培养细胞睾酮在hCG刺激下分泌能力变化。结果:优化培养体系能够明显促进3周龄大鼠睾丸Leydig细胞大量增殖,群体倍增时间为(2.26±0.31)d,传统培养体系培养细胞群体倍增时间为(16.32±2.14)d,两者差异有显著性(P<0.05);原代细胞经流式细胞术鉴定,3β-HSD阳性细胞所占比例分别为(54.3±7.1)%,培养4d后,增殖细胞3β-HSD阳性细胞率为(93.6±4.6)%。增殖细胞均有睾酮生成功能,在hCG刺激下睾酮分泌均明显上升(P<0.05)。结论:优化培养体系能够促进差速贴壁法获得的睾丸Leydig细胞大量增殖。     

Age‐related changes in gap junctional intercellular communication in osteoblastic cells

Aging demonstrates deleterious effects upon the skeleton which can predispose an individual to osteoporosis and related fractures. Despite the well‐documented evidence that aging decreases bone formation, there remains little understanding whereby cellular aging alters skeletal homeostasis. We, and others, have previously demonstrated that gap junctions—membrane‐spanning channels that allow direct cell‐to‐cell conductance of small signaling molecules—are critically involved in osteoblast differentiation and skeletal homeostasis. We examined whether the capacity of rat osteoblastic cells to form gap junctions and respond to known modulators of gap junction intercellular communication (GJIC) was dependent on the age of the animal from which they were isolated. We observed no effect of age upon osteoblastic Cx43 mRNA, protein or GJIC. We also examined age‐related changes in PTH‐stimulated GJIC. PTH demonstrated age‐dependent effects upon GJIC: Osteoblastic cells from young rats increased GJIC in response to PTH, whereas there was no change in GJIC in response to PTH in osteoblastic cells from mature or old rats. PTH‐stimulated GJIC occurred independently of changes in Cx43 mRNA or protein expression. Cholera toxin significantly increased GJIC in osteoblastic cells from young rats compared to those from mature and old rats. These data demonstrate an age‐related impairment in the capacity of osteoblastic cells to generate functional gap junctions in response to PTH, and suggest that an age‐related defect in G protein‐coupled adenylate cyclase activity at least partially contributes to decreased PTH‐stimulated GJIC. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1979–1984, 2012     

Nitric oxide-mediated regulation of connexin43 expression and gap junctional intercellular communication in mesangial cells

This study investigated a potential role of nitric oxide (NO) in the regulation of gap junctional intercellular communication (GJIC). Incubation of mesangial cells (MC) with NO donor S-nitroso-N-acetylpenicillamine (SNAP) enhanced both basal and 8-bromo-cAMP-stimulated GJIC as well as expression of gap junction protein connexin43 (Cx43). This potentiating action of SNAP on Cx43 expression was mimicked by two other NO donors and significantly blocked by soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3,-alpha]quinoxalin-1-1. Guanosine 3',5'-cyclic monophosphate (cGMP) analogue 8-bromo-cGMP exerted an effect similar to NO, whereas another cGMP analogue, 8-pCPT-cGMP, which selectively activates cGMP-dependent kinase without affecting cGMP-inhibited phosphodiesterase (PDE3), had no effect. Moreover, the synergistic action of NO on Cx43 expression was completely prevented by protein kinase A inhibitor H89 but not by cGMP-dependent kinase inhibitor Rp-8-Br-PET-cGMP. These results suggested a possible involvement of NO-cAMP interaction via cGMP-mediated inhibition of PDE3. Indeed, PDE3 inhibitor cilostamide caused potentiation of 8-bromo-cAMP-elicited elevations of Cx43 expression that is similar to the effect of SNAP, and an elevation of intracellular cAMP was detected in SNAP-treated cells. With the use of genetically engineered reporter MC that express secreted alkaline phosphatase under the control of the cAMP response element, significant potentiation of cAMP-elicited activation of cAMP response element by SNAP was found. This effect was abrogated in the presence of PDE3 inhibitor cilostamide. Taken together, the results suggest that NO is involved in the control of GJIC and Cx43 expression. This effect of NO is due to activation of protein kinase A via cGMP-dependent inhibition of PDE3 activity.     

棉酚对睾丸支持细胞间隙连接蛋白表达的影响

目的:探讨药物棉酚对睾丸Sertoli细胞间隙连接蛋白Cx43表达的影响。方法:培养TM4睾丸Sertoli细胞,用1.25、2.5、5、10μmol/L的棉酚分别染毒细胞6、12、24、48 h。CCk-8试剂盒检测细胞毒性,应用细胞免疫荧光化学、RT-PCR检测Cx43在正常TM4细胞和在不同浓度及不同染毒时间的TM4细胞中的表达情况。结果:半定量RT-PCR及免疫荧光结果显示,正常TM4细胞中有较多的Cx43表达;棉酚染毒24 h后,Cx43 mRNA水平开始随时间增加而逐渐下降(P<0.05),且随剂量增加Cx43蛋白表达强度逐渐减弱(P<0.05)。结论:棉酚可抑制TM4细胞表达Cx43,可能是其抗生育的机制之一。     

Retinoids inhibit squamous cell carcinoma growth and intercellular communication

BACKGROUND: Retinoids have been shown to inhibit the growth of squamous cell carcinoma and other malignancies. They have also been shown to alter gap junctional intercellular communication (GJIC) and the expression of connexins, the protein subunits of gap junctions. We report in this study that the alteration of GJIC by retinoids may be directly related to inhibitory effects on cell growth. MATERIALS AND METHODS: SCC-13 cells were treated with all-trans retinoic acid (tRA) and 13-cis retinoic acid (cRA) at 10(-7) and 10(-6) M concentrations in culture. No treatment and ethanol vehicle controls were included for each experiment. Serial cell counts of parallel cultures were performed to determine cell growth. The parachute technique was performed in combination with fluorescence activated cell sorting (FACS) analysis to determine GJIC. Northern and Western blot analysis were performed to assess connexin mRNA and protein expression. RESULTS: The growth rate was inhibited for cells treated with tRA (10(-6) M) (P < 0.05) and cRA (10(-6) M) (P = 0.068) vs. vehicle control. GJIC was significantly inhibited with both tRA (10(-7) and 10(-6) M) (P < 0.001) and cRA (10(-7) and 10(-6) M) (P < 0.001) at 24, 48, and 96 h as determined by FACS analysis. To correlate GJIC with cell growth, we studied the effect of glycyrrhetinic acid, a known inhibitor of GJIC. Glycyrrhetinic acid also significantly inhibited cell growth (P < 0.05) vs. control. Connexin 26 and connexin 43 mRNA and protein expression were not significantly altered after retinoid treatment. CONCLUSION: Retinoic acids inhibit both cell growth and GJIC in SCC-13 cells. Retinoids may inhibit cell growth through alteration of GJIC in SCC-13 cells.     

豹皮樟总黄酮通过增强小鼠睾丸Leydig细胞缝隙连接功能减轻奥沙利铂的细胞毒作用

目的:探讨豹皮樟总黄酮(TFLC)对体外培养的小鼠睾丸Leydig细胞系(TM3)缝隙连接(GJ)功能的作用,以及TFLC是否减轻化疗药奥沙利铂(OHP)的细胞毒作用。方法:荧光示踪法测定体外培养的TM3细胞之间荧光传递,反映GJ的功能;Western印迹法检测TFLC对连接蛋白43(Cx43)表达的影响;细胞免疫荧光法观察TFLC对TM3细胞胞膜Cx43蛋白表达的影响;MTT法检测OHP的细胞毒作用,以及TFLC对OHP细胞毒的影响。结果:在TM3细胞中GJ的功能随着TFLC浓度的增加而增强;Western印迹和免疫荧光实验结果显示TFLC可显著增强TM3细胞中Cx43蛋白和膜Cx43蛋白的表达;MTT结果表明,高密度接种细胞(生长融合,有GJ形成),20μg/ml TFLC增强细胞GJ功能,且减轻OHP的细胞毒作用[细胞存活率(89.5±1.8)%高于单用ONP组(80.0±1.5)%,(P0.05)];低密度接种细胞(生长未融合,无GJ形成),TFLC对OHP的细胞毒作用没有影响(P0.05)。结论:TFLC增强睾丸正常细胞TM3中Cx43的表达,并增强细胞间的GJ功能;TFLC减轻OHP在TM3细胞的毒性作用,并可能与增强GJ功能有关。     

ODDD‐Linked Cx43 Mutants Reduce Endogenous Cx43 Expression and Function in Osteoblasts and Inhibit Late Stage Differentiation

Introduction: Bone development and modeling requires precise gap junctional intercellular communication (GJIC). Oculodentodigital dysplasia (ODDD) is an autosomal dominant human disease caused by mutations in the gene (GJA1) encoding the gap junction protein, connexin43 (Cx43). The disease is characterized by craniofacial bone deformities and limb abnormalities. It is our hypothesis that Cx43 mutation causes osteoblast dysfunction, which may contribute to the bone phenotype of ODDD. Materials and Methods: We expressed human and mouse ODDD‐linked Cx43 mutants in MC3T3‐E1 cells and primary mouse osteoblasts by retroviral infection and evaluated their in vitro differentiation as an index of osteoblast function. We compared these findings to the differentiation of osteoblasts isolated from a mouse model of ODDD that harbors a germ line Cx43 mutation and exhibits craniofacial and limb defects mimicking human ODDD. We determined the differentiation status of osteoblasts by analyzing alkaline phosphatase activity and the expression levels of osteoblast markers including bone sialoprotein and osteocalcin. Results: We showed that ODDD‐linked Cx43 mutants are loss‐of‐function and dominant‐negative to co‐expressed Cx43 and, furthermore, greatly inhibit functional GJIC in osteoblasts. Surprisingly, the mutants had only a minor effect on osteoblast differentiation when introduced into lineage committed cells. In contrast, osteoblasts isolated from the ODDD mouse model exhibited impaired late stage differentiation. Conclusions: Expression of human and mouse ODDD‐linked Cx43 mutants failed to significantly impair differentiation in cells predisposed to the osteoblast lineage; however, germ line reduction of Cx43‐based GJIC leads to impaired osteoblast differentiation, which may account for the bone phenotypes observed in ODDD patients.