Differential regulation of collagen types I and III expression in cardiac fibroblasts by AGEs through TRB3/MAPK signaling pathway

Advanced glycation end products (AGEs) play an important role in collagen deposition in diabetic cardiomyopathy. TRB3, a mammalian homolog of Drosophila tribbles, functions to increase glucose intolerance and regulates cell proliferation. We demonstrated that AGEs induce collagen type I expression but inhibit collagen type III expression, accompanied by increased TRB3 expression. Furthermore, the collagen type I induced byAGEs was down-regulated after inhibition of ERK and p38-MAPK, the collagen type III reduced by AGEs was up-regulated after inhibition of ERK. The expression of collagen types I and III regulated by AGEs through MAPK was partly reversed after treatment with TRB3 siRNA. It suggests that the TRB3/MAPK signaling pathway participates in the regulation of collagen types I and III by AGEs and may provide new therapeutic strategies for diabetic cardiomyopathy. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 08 May 2008; received after revision 25 June 2008; accepted 22 July 2008 M. Tang, M. Zhong: These two authors contributed equally to this work.     

TGFβ1shRNA靶向抑制离体胎鼠肺成纤维细胞TGFfβ1基因表达

目的:探讨自行设计的TGFβ1shRNA对离体胎鼠肺成纤维细胞TGFβ1基因表达的干扰作用,为研究纤维化病变的基因治疗提供技术基础和依据.方法:原代培养胎鼠肺成纤维细胞,并建立细胞高氧损伤模型.针对大鼠TGFβ1基因mRNA序列,设计、合成携带3条TGFβ1shRNA绿色荧光蛋白融合表达质粒载体,并设阴性质粒组和空白组为对照,通过JetPEI包裹分别转染上述高氧损伤的胎鼠肺成纤维细胞.转染后24、48和72 h收集细胞,在荧光显微镜下观察干扰效果,采用实时荧光定量PCR检测TGFβ1基因表达情况,并计算干扰效率.结果:①成功培养胎鼠肺成纤维细胞,并建立细胞高氧损伤模型;②荧光显微镜下观察,可见转染后24、48和72 h TG-Fβ1shRNA质粒组细胞绿色荧光强度均明显弱于阴性质粒组细胞,空质粒载体组未产生绿色荧光;荧光定量PCR检测转染后胎鼠肺成纤维细胞TGFβ1 mRNA表达量,转染后24、48和72 hTGFβ1shRNA质粒组TGFβ1 mRNA表达量均显著低于阴性质粒组(P<0.01),其基因干扰效率则依次递减,分别为97.3%、96.9%和71.7%.结论:本研究证明自行设计的TGFβ1shRNA转染胎鼠肺成纤维细胞后24、48和72 h均能够高效干扰TGFβ1基因的表达,其基因干扰效率呈现一定的时间依赖性.     

多溴联苯醚对HL-7702细胞和小鼠皮肤成纤维细胞间隙连接通讯的影响

利用划痕染料示踪标记(SLDT)方法,检测了多溴联苯醚(PBDEs)对人肝正常细胞(HL-7702)与小鼠皮肤成纤维细胞间隙连接通讯(GJIC)的影响.结果表明,PBDE-47与PBDE-209均显著抑制HL-7702细胞的GJIC(10～50μmol.L-1),随着剂量的升高,抑制作用随之增强.在小鼠皮肤成纤维细胞中,PBDE-47在3.75～50μmol.L-1范围内对GJIC有显著的抑制作用,而PBDE-209在15～50μmol.L-1范围内对GJIC有显著的抑制作用,在两种细胞中,PBDE-47的抑制作用大于PBDE-209.停止染毒后,细胞GJIC有一定程度的恢复.实验表明PBDEs可抑制细胞间隙连接通讯,为进一步研究PBDEs的毒性机制提供了科学依据.     

昆明小鼠胚胎成纤维细胞的分离与体外培养

研究了昆明小鼠胚胎成纤维细胞的分离、培养和生长特征,建立了快速、稳定的优质饲养层细胞培养体系.从不同日龄的胎鼠均分离到胚胎成纤维细胞,但最佳分离时间为13.5~14.5d;三种分离原代胚胎成纤维细胞的方法中胰酶消化法效果最好,能在较短的周期内获得大量原代及传代细胞;MEF细胞形态以小梭形为主,呈漩涡状、火焰状生长;增殖速度较快,每1~2d可传一代,按1∶3比例常规传代;5代以内适宜制作饲养层用,5代以后细胞开始变形呈现典型的衰老特征.     

Regulations of Thyroid Hormone on Cardiac Protein Kinase C Signal Pathway in vitro

The experiments were conducted to assess the influences of thyroid hormone on cardiac protein kinase C(PKC) signal pathway with cultured cardiac myocytes and fibroblasts as the models. Cells were pretreated with 1% newborn calf serum (NCS) or angiotensin Ⅱ (Ang Ⅱ), and then following by a triiodothyronine (T3) treatment. The PKC activity, PKCa and PKCε expressions were analyzed and compared. In 1% NCS pretreatment, T3 could inhibit PKC activity and PKCε expression in cardiac myocytes. The AngⅡ pretreatment led to an increase of PKC acUvity and PKCε expression in cardiac myocytes, and an increase of PKC activity in cardiac fibroblasts. Following by T3 treatment, the increased PKC activity and PKCε expression in cardiac myocytes were markedly decreased. In conclusion, whether in 1% NCS or in Ang lI pretreatment, T3 could inhibit PKC activity and PKCε expression in cardiac myocytes.     

The role of hsp70 in protection and repair of luciferase activity in vivo; experimental data and mathematical modelling

The stably transfected rat cell line HR24 expressing high levels of the inducible human hsp70 and its parental cell line Rat-1 were used for in vivo studies to analyse the role of hsp70 during thermal protein denaturation and the subsequent renaturation. In order to monitor denaturation and renaturation of a cellular protein in vivo, both cell lines were transiently transfected with firefly luciferase (Luc). The continuous monitoring of Luc activity during and after heat stress allowed a detailed analysis of the inactivation and reactivation kinetics in cells grown in monolayers. The aim of these studies was to distinguish a protective effect of increased hsp70 levels during heat shock-induced protein inactivation from a stimulation of reactivation. In this paper we show that in cells that are stably transfected with hsp70, thermal Luc inactivation decreased, and subsequent reactivation yielded higher activity levels, compared with the parental cells. The difference in early inactivation kinetics observed in the two cell lines suggests an immediate effect of the presence of an extra amount of hsp70 on enzyme inactivation. Using different mathematical models, the heat-induced inactivation and reactivation kinetics was compared with simulations of denaturation and renaturation. It is concluded that the model in which it is assumed that hsp70 is able to interact with partially denatured proteins, which did not yet lose their enzymatic activity, most optimally explains the experimental observations. Received 2 December 1998; received after revision 19 February 1999; accepted 18 March 1999     

昆明鼠胚胎干细胞的分离培养与鉴定

目的：从昆明系小鼠的早期胚胎分离和培养胚胎干细胞(ES细胞)．方法：收集小鼠3．5d胚龄的囊胚，将其培养在小鼠胚胎成纤维细胞饲养层上，5—6d后取隆起生长的内细胞团块分离后再培养，观察集落的生长情况并通过碱性磷酸酶染色、原位杂交、细胞核型分析等对细胞集落进行鉴定．结果：KS细胞集落性生长，符合小鼠胚胎干细胞的一系列特性．结论：昆明系小鼠囊胚在胚胎成纤维细胞饲养层上可以发育成ES细胞，并能进行传代培养．     

Phenytoin-induced DNA synthesis and inositol 1,4,5-triphosphate formation in L-929 fibroblasts

Summary Culture of L-929 fibroblasts in the presence of phenytoin (2.5–5.0 g/ml) increased DNA synthesis, as indicated by increased [³H]thymidine uptake, while a higher dose (20 g/ml) inhibited DNA synthesis. In like manner, a low dose of phenytoin (5.0 g/ml) was effective in increasing inositol 1,4,5-trisphosphate formation while a higher dose (10 g/ml) tended to inhibit this activity. These data suggest that the formation of inositol phosphate second messengers may play a role in phenytoin-induced fibroblast proliferation and connective tissue growth.     

葫芦巴总皂苷对心肌成纤维细胞转分化的影响及机制的实验研究

目的探讨葫芦巴总皂苷(Trigonella foenum greacum.L Saponin,TFGs)对尾加压素Ⅱ(UrotensinⅡ,UⅡ)诱导体外培养的大鼠心肌间质成纤维细胞(CFs)发生肌成纤维细胞转分化的干预作用及相关分子机制.方法体外培养大鼠心肌间质成纤维细胞,随机分为正常对照组、UⅡ刺激组和TFGs干预组.正常对照组在整个培养过程中未加任何刺激;UⅡ刺激组加入10-8mol/L的尾加压素Ⅱ培养,并分别终止培养于12,24和48 h;TFGs干预组将UⅡ作为刺激因素,分别加入终浓度为0,25,50,100和200 mg/L的TFGs.应用免疫荧光和免疫组化方法检测显示α-SMA的表达,应用RT-PCR和免疫印迹法分别检测结缔组织生长因子(CTGF)的基因及蛋白表达.结果免疫荧光检测显示,培养24 h后,正常对照组细胞胞浆中仅有少量α-SMA表达,而α-SMA表达量在经UⅡ作用后明显增多.尾加压素Ⅱ干预CFs不同时间后(12,24,48 h),免疫组化显示α-SMA表达量逐渐增加.UⅡ的这种诱导CFs发生肌成纤维细胞转分化作用可被含TFGs的培养液所抑制,且呈浓度和时间依赖性.与对照组比较,UⅡ刺激组的CTGF的基因及蛋白表达均明显增高(P<0.01).而TFGs则可以抑制UⅡ诱导的CTGF基因及蛋白表达量的上调(P<0.01).结论尾加压素Ⅱ具有诱导大鼠心肌间质成纤维细胞发生肌成纤维细胞转分化的作用,此作用可能与其促进CTGF的基因及蛋白表达有关.葫芦巴总皂苷能有效地抑制大鼠CFs的转分化,并且下调UⅡ诱导的CTGF的过表达.这进一步明确UⅡ在心肌纤维化发生、发展中的作用,也为临床应用葫芦巴总皂苷防治心肌纤维化提供了实验依据.     

Effect of temperature on in vitro proliferative activity of human umbilical vein endothelial cells

Human umbilical vein endothelial cells, skin fibroblasts, and retinal pigment epithelial cells are cultivated in medium supplemented with 15 to 20% serum in our laboratory. The effects of various incubation temperatures on the proliferation of these cells was examined. Our study shows that the mitogenic response of the endothelial cells to a change of temperature differed markedly from that of the fibroblasts and epithelial cells. Cultivation of human umbilical vein endothelial at 37°C required seeding densities as high as 1–2×10⁴ cells/cm², and yet resulted in a low growth rate and premature senescence. However, under the same culture conditions, but at 33°C, the proliferative capacity of these endothelial cells was potentiated. The results were striking; at 33°C the cells grew actively and the life span was extended. The number of cumulative population doublings increased fourfold compared with that for the same cells cultivated at 37°C. The inoculum size could be reduced, since at 33°C the endothelial cells were able to replicate at seeding densities as low as 20 cells/cm². The cells serially subcultured at 33°C retained morphological features and specific immunological markers of endothelial cells.