间充质干细胞及其外泌体促血管再生的分子机制研究进展

间充质干细胞具有多向分化潜能,并能招募血管内皮细胞,促进其增殖、迁移和血管形成,改善血流灌注和氧供。间充质干细胞分泌的外泌体含有其来源细胞特异性蛋白质和核酸,能够部分模拟间充质干细胞功能,具有成血管作用,且能透过血脑屏障和肠屏障等,可替代间充质干细胞治疗缺血性疾病的再血管化治疗。本文将对间充质干细胞及其外泌体的生物学特征、缺血性疾病中的促血管再生作用机制,以及低氧条件下低氧诱导因子-1α对间充质干细胞及其外泌体在缺血性疾病中的促血管再生作用机制的影响最新研究进展作一综述

Effect of silencing LC3 on apoptosis of mouse hepatocellular carcinoma Heap1-6 cells

目的建立小鼠LC3基因沉默的Heap1-6稳定表达细胞系，探讨其对衣霉素诱导的肝癌细胞凋亡的影响。方法设计并合成一段针对小鼠LC3基因的shRNA及不针对任何基因的shRNA作为阴性对照，将它们退火后连接构建重组载体，转化扩增及酶切鉴定之后将重组质粒与病毒包装、包膜质粒共同转染293T，收集病毒上清转染Heap1-6细胞，嘌呤霉素筛选10 d，获得稳定的细胞株。以导入LC3基因shRNA的Heap1-6为实验组（Heap1-6 shLC3），以导入shcoo2的Heap1-6为对照组（Heap1-6 shctrl）。衣霉素处理实验组和对照组的细胞，Western Blot检测LC3Ⅱ、c-Caspase3、Caspase9蛋白的表达，流式细胞术检测细胞凋亡。Western Blot 条带灰度值之间两组比较采用独立样本的t检验。结果成功构建了pLKO.1-shLC3重组慢病毒载体，与野生型的Heap1-6相比，LC3基因沉默之后，LC3Ⅱ蛋白表达水平降低了62.9﹪（P 〈 0.01）；野生型的Heap1-6和LC3基因沉默之后的Heap1-6 shLC3都经Tm处理12 h之后，后者LC3Ⅱ蛋白表达水平降低了58.6﹪（P 〈 0.01）。与对照组Heap1-6 shctrl相比，衣霉素作用12 h后实验组Heap1-6 shLC3 c-Caspase3增加了37.7﹪（P = 0.007），Caspase9增加了37.1﹪（P = 0.023））；衣霉素作用24 h后shLC3组c-Caspase3增加了12.6﹪（P = 0.04）， Caspase9增加了14.3﹪（P = 0.043）。药物干预12 h和24 h后，Heap1-6 shLC3组比对照组Heap1-6 shcoo2凋亡比例分别增加22.8﹪和18.6﹪。结论成功建立小鼠LC3基因沉默的Heap1-6稳定表达细胞系，LC3基因沉默促进衣霉素诱导的小鼠肝癌细胞Heap1-6的凋亡。Objective To establish a stable hepatocellular carcinoma Heap1-6 cell line expressing shRNA against mouse LC3 and to study apoptosis of Heap1-6 cells treated with tunicamycin. Methods shRNA targeting LC3 gene and negative shRNA were designed and synthesized, pLKO.1-TRC-shRNA LC3 vector and negative vector were constructed. After amplification and identification, the recombinant lentivirus vectors were transfected into 293T cells with packaging and envelope plasmids. The supernatant of 293T ceils transfected with recombinant vector was collected, and Heap1-6 cells were transfected with plasmids, and treated with puromycin for ten days to acquire a cell line with stable expression of shRNA against mouse LC3. Western blot analysis was used to detect the expression level of LC3 Ⅱ, cleaved-caspase3, and caspase9 protein respectively. Apoptotic cells were measured by flow cytometry. Results We successfully constructed pLKO. 1-shLC3 lentivirus vector. Before treated by tunicamycin, the level of LC3 Ⅱ in the Heap1-6 shLC3 cells was decreased by 62.9 % compared with that in the WT Heap1-6 cells （P = 0.0001 ）. After being treated by tunicamycin for 12 h, the level of LC3 Ⅱ in Heap1-6 shLC3 cells was decreased by 58.6 % compared with that in the WT Heapl-6 cells P = 0.0003 ）. Compared with the control group （Heap1-6 cells transfected with negative shRNA vector）, the level of cleaved-caspase3 and caspase9 in the shLC3 group was increased by 37.7 % and 37.1% respectively under tunicamycin for 12 h （P = 0.007, 0.023 ）. And the level of the same two proteins in the shRNA group was elevated by 12.6 % and 14.3 % compared with those of Heap1-6 shctrl cells respectively （P = 0.040, 0.043）. The ratio of apoptotic cells of the experiment group was increased by 22.8 % and 18.6 % compared with that of the control treated with ttmicamycin for 12 h and 24 h, respectively. Conclusion LC3 knockdown could promote apoptosis of mouse hepatocellular carcinoma Heap 1-6 cell line induced by tunicamycin.国家自然科学基金面上项目（81270431

间充质细胞外泌体促进小鼠胰岛内皮细胞血管生成的研究

目的探讨间充质细胞（MSC）外泌体对低氧条件下胰岛内皮细胞（MS-1）血管生成的影响。方法 MSC无血清低氧条件培养48 h,超滤离心法富集条件培养基中的外泌体,采用电镜和Western Blot的方法进行鉴定;通过血管形成试验比较分析不同条件下:常氧培养组（NOR组,21%O2、5%CO2）、低浓度氧培养组（HYP组,2%O2、5%CO2）、外泌体+低浓度氧共培养组（HYP+EXO组,2%O2、5%CO2）,MS-1细胞的血管形成能力;image J软件分析血管形成长度;PCR、Q-PCR检测血管内皮生长因子（VEGF） RNA水平的表达,Western Blot检测VEGF、HIF1α蛋白水平表达以及mTOR信号通路激活情况。采用单因素方差分析和SNK-q检验统计学分析。结果超滤离心法富集的MSC条件培养基中的外泌体,大小为30～100 nm,表达CD9,CD63,CD81等外泌体表面标志物;血管形成试验结果显示,低氧促进MS-1血管生成,HYP+EXO组形成明显的血管网状结构;HYP+EXO组血管形成相对长度（2386.0±137.7）像素与NOR组（393.3±174.2）像素和HYP组（1467.0±230.0）像素相比增强,差异有统计学意义（t=12.30,P=0.0065;t=15.74,P=0.0040）; PCR结果显示,HYP+EXO组VEGF相对表达量（20.26±9.972）较常氧对照组（1.000）和低氧组（6.521±3.501）均增强,差异有统计学意义（t=5.462,P=0.0009;t=4.238,P=0.0038）;同时,Western Blot结果显示VEGF蛋白水平表达升高,HIF1-α表达上调,mTOR发生磷酸化。结论 MSC外泌体可促进低氧条件下的小鼠胰岛内皮细胞血管生成。MSC外泌体可能通过上调HIF1-α,调节VEGF表达,激活mTOR信号通路,促进胰岛内皮细胞血管生成。国家自然科学基金青年项目(81601618);;福建省自然科学基金面上项目(2016J01582、2016J01580、2018J01349);;福建省科技创新联合资金重大项目(2017Y9127

Promotion of proliferation of luminal B breast cancer cells by mesenchymal stem cells and its underlying molecular mechanisms

目的分析人脐带间充质干细胞(hUC-MSCs)对Luminal B型乳腺癌细胞生长增殖的影响,并初步探讨其可能的分子机理。方法绿色荧光蛋白(GFP)和荧光素酶共表达慢病毒感染人Luminal B型乳腺癌细胞BT474,并经嘌呤霉素筛选两周后,于荧光显微镜下观察GFP的表达情况,IVIS Kinetic成像系统拍照以观察和记录慢病毒感染后BT474细胞荧光素酶的表达情况;荧光显微镜下直接观察,结合MTS实验分析hUC-MSCs共培养或其浓缩上清处理对GFP和荧光素酶共表达BT474细胞生长增殖的影响;Western blot法检测hUC-MSCs浓缩上清处理对BT474细胞Akt和MAPK信号通路激活情况以及下游细胞周期调控蛋白Cyclin D1表达的影响;常规RT-PCR法检测hUC-MSCs中NRG-1、NRG-2、IGF-Ⅰ、IGF-Ⅱ和EGF等配体的表达。荧光素酶表达强度与细胞数量的相关性经由Excel软件行统计学分析,MTS实验数据则经由SPSS13.0统计软件行统计学分析。结果荧光显微镜和IVIS Kinetic成像系统的观察结果分别证实,GFP和荧光素酶经慢病毒载体系统的介导可在BT474细胞中成功地共表达,且荧光素酶的表达强度与细胞数量呈直线相关。MSCs共培养或其浓缩上清处理均可显著促进Luminal B型乳腺癌细胞BT474的生长增殖,其细胞存活比例分别为各自对照组的148.06%(P<0.005)和147.99%(P<0.001);MSCs浓缩上清处理同时激活BT474细胞内Akt和MAPK信号通路,并上调细胞周期调控蛋白Cyclin D1表达。此外,RT-PCR结果显示,hUC-MSCs中NRG-1和EGF的mRNAs水平呈高表达,而NRG-2、IGF-Ⅰ和IGF-Ⅱ等配体的mRNAs表达也可见。结论 MSCs可通过表达并分泌NRG-1等配体,从而激活Luminal B型乳腺癌细胞BT474的下游Akt和MAPK信号转导通路以上调细胞周期调控蛋白Cyclin D1的表达,进而促进其生长增殖。Objective To investigate the effect of human umbilical cord mesenchymal stem cells(hUC-MSCs) on proliferation of luminal B breast cancer cells and its underlying molecular mechanisms. Methods Human luminal B breast cancer cells BT474 were infected with GFP and luciferase co-expressing lentiviruses and then subjected for selection with Puromycin for 2 weeks. The expression of GFP and luciferase was detected by fluorescent microscopy and IVIS Kinetic image system, respectively. The effect of coculture or treatment with conditioned medium of hUCMSCs on proliferation of BT474 was analyzed with MTS assay. Western blot was carried out to detect the effect of treatment with conditioned medium of hUC-MSCs on the activation of both Akt and MAPK signalings in BT474, as well as the expression of downstream cell cycle regulator Cyclin D1. Regular RT-PCR was applied to analyze the mRNAs expression of ligands such as NRG-1, NRG-2, IGF-Ⅰ, IGF-Ⅱ, and EGF in hUC-MSCs. The correlation between relative luciferase activity and cell number was analyzed with Excel software, while MTS assay data was statistically analyzed with SPSS 13.0 software. Results The co-expression of GFP and luciferase in BT474 via lentiviral expression system was visualized by fluorescent microscopy and IVIS Kinetic image system. The linear correlation between relative luciferase activity and cell number was determined by curve fitting analysis. Coculture or treatment with conditioned medium of hUC-MSC significantly promoted the proliferation of BT474, with survival rates being 148.06 %(P < 0.005)and 147.99 %(P < 0.001)of control, respectively. In addition, treatment with conditioned medium of hUC-MSC was shown to induce activation of both Akt and MAPK signalings, which further upregulated the expression of Cyclin D1. Moreover, high mRNAs expression levels of both NRG-1 and EGF, as well as moderate mRNAs expression levels NRG-2, IGF-Ⅰ, and IGF-Ⅱ were showed by RT-PCR. Conclusion Our results here demonstrated that MSCs may promote the proliferation of luminal B breast cancer cells through paracrine of ligands such as NRG-1, which in turn results in the activation of both Akt and MAPK signalings and upregulation of the expression of Cyclin D1.国家自然科学基金面上项目(81272922);; 福建省自然科学基金面上项目(2016J01577);; 福州总医院院内课题国际合作研究专项(2015G01

骨髓间充质细胞联合PDMS支架构建移植胰岛微环境的实验研究

目的为了提高移植胰岛的活性和功能,构建适合移植胰岛生存的微环境。方法采用聚二甲基硅氧烷(PDMS)和氯化钠晶体构建三维支架,联合骨髓间充质细胞(MSCs)、纤维蛋白和胰岛共同构建迷你\"人工胰腺\"。采用链脲佐菌素(STZ)诱导的糖尿病大鼠移植模型评价效果,将\"人工胰腺\"移植到糖尿病大鼠大网膜内,对照组行假手术,术后隔天监测移植大鼠血糖水平;数据采用t检验和曼-惠特尼U检验。结果用PDMS构建的三维巨孔支架,支架内可见大量不规则孔洞空间。胰岛和MSCs可成功装载入支架内,HE染色结果显示,支架孔内存在胰岛,胰岛周围包绕有MSCs。糖尿病大鼠大网膜内移植结果显示,移植后各时间点(1,3,5,7 d),\"人工胰腺\"移植组糖尿病大鼠血糖水平分别为(278.70±86.06) mg/dl、(323.50±44.29) mg/dl、(283.30±74.00) mg/dl、(304.80±13.33) mg/dl,较假手术对照组(606.00±52.40) mg/dl、(589.70±55.78) mg/dl、(615.00±54.84) mg/dl、(630.30±48.17) mg/dl均降低,差异具有统计学意义(t=7.96、9.15、8.82,U=0.00,P均<0.01)。结论 MSCs联合PDMS三维支架构建的微环境,可为移植胰岛提供生存的环境,为临床开展胰岛移植提供新的策略