骨髓间充质干细胞分化为胰岛细胞治疗糖尿病

糖尿病已成为严重危害人类健康的疾病之一。目前,移植胰岛治疗糖尿病已初见疗效,但由于胰岛来源匮乏和免疫排斥反应而受阻。骨髓间充质干细胞(bonemarrowmesenchymalstemcells,BMMSCs)取材方便,容易进行体外分离、培养和纯化,且具有跨越分化潜能。若将自体BMMSCs诱导分化为胰岛细胞,可望解决细胞来源和免疫排除问题,实现糖尿病的自体细胞治疗。现对体外诱导BMMSCs分化为胰岛细胞治疗糖尿病的研究进展进行综述,并指出了存在问题和今后的研究方向。     

骨髓间充质干细胞分化过程中表观遗传调控机制的研究进展北大核心CSCD

骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMMSCs)具有自我更新的能力和多向分化潜能,在体外可被诱导分化成多种细胞类型,在骨及软骨组织修复中具有重要的临床应用价值。为研发有效促进BMMSCs定向分化的药物,将BMMSCs更合理安全地应用于临床,有必要阐明表观遗传在BMMSCs分化过程中的调控机制。由于BMMSCs的异常分化可导致疾病的发生,其分化调控机制一直是研究的热点。表观遗传调控,如DNA甲基化、组蛋白乙酰化、组蛋白甲基化及非编码RNA等,对决定BMMSCs分化方向至关重要。阐明表观遗传在BMMSCs分化过程中的调控机制,将有助于研发有效促进BMMSCs定向分化的药物,更合理安全地将BMMSCs应用于临床。就BMMSCs分化中的主要表观遗传调控机制的最新研究进展做一综述,并进行了总结。     

骨髓间充质干细胞分化过程中表观遗传调控机制的研究进展

骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMMSCs)具有自我更新的能力和多向分化潜能,在体外可被诱导分化成多种细胞类型,在骨及软骨组织修复中具有重要的临床应用价值。为研发有效促进BMMSCs定向分化的药物,将BMMSCs更合理安全地应用于临床,有必要阐明表观遗传在BMMSCs分化过程中的调控机制。由于BMMSCs的异常分化可导致疾病的发生,其分化调控机制一直是研究的热点。表观遗传调控,如DNA甲基化、组蛋白乙酰化、组蛋白甲基化及非编码RNA等,对决定BMMSCs分化方向至关重要。阐明表观遗传在BMMSCs分化过程中的调控机制,将有助于研发有效促进BMMSCs定向分化的药物,更合理安全地将BMMSCs应用于临床。就BMMSCs分化中的主要表观遗传调控机制的最新研究进展做一综述,并进行了总结。     

CTLA4基因修饰骨髓间充质干细胞向肝细胞诱导分化及其免疫抑制功能研究

用携带CTLA4Ig基因的重组腺病毒感染大鼠骨髓间充质干细胞(bone marrow mesenchymal stern cels,BMMSCs),体外向肝细胞诱导分化,并检测其免疫抑制功能.用含有HGF等细胞因子培养液诱导重组腺病毒Ad-CTLA4Ig感染大鼠BMMSCs向肝细胞分化.诱导后的细胞可表达AFP、Alb和CK18等肝细胞标志,同时还具有储存糖原和摄取、排泌靛青绿等肝细胞功能.转基因BMMSCs在未经诱导和诱导后均可表达CTLA4Ig,诱导14天时表达量有所减弱.单向混合淋巴细胞反应证实,诱导7天的转基因BMMSCs具有明显的抑制淋巴细胞反应的作用,其抑制作用明显高于未转基因BMMSCs,且CTLA4Ig基因修饰BMMSCs输注还可以明显延长肝移植大鼠的存活时间.用重组腺病毒Ad-CTLA4Ig对BMMSCs进行基因修饰,一方面不会影响BMMSCs的肝细胞分化潜能,另一方面使BMMSCs的免疫抑制特性得到进一步强化.     

转化生长因子-β1对大鼠骨髓间充质干细胞增殖及Slug表达的影响

目的检测转化生长因子-β1(transforming growth factor-β1,TGF-β1)对体外培养大鼠骨髓间充质干细胞(bone marrow mesenchymal stem cell,BMMSCs)增殖及Slug表达的影响。方法采用密度梯度离心结合贴壁法分离、培养大鼠BMMSCs,用免疫组织化学方法对培养第3代的细胞进行鉴定。用MTT法检测不同浓度TGF-β1对细胞增殖的影响;免疫荧光和免疫印迹法检测TGF-β1处理前后Slug的表达情况。结果密度梯度离心结合贴壁法能有效分离、纯化大鼠BMMSCs,免疫组织化学法检测显示CD29、CD44表达阳性,而CD34、CD45表达阴性;低浓度TGF-β1对BMMSCs的增殖有促进作用,高浓度却抑制BMMSCs的增殖。TGF-β1处理24 h,Slug蛋白表达明显增强。结论一定浓度的TGF-β1可以促进BMMSCs的增殖,而且引起Slug蛋白增加。     

多能成体祖细胞培养条件促进人脂肪干细胞的视网膜神经保护功能

目的：检测多能成体祖细胞（MAPC）的培养条件对猴骨髓间充质细胞（BMMSCs）和人脂肪干细胞（hADSCs）生长的影响,旨在获得更适合治疗视网膜变性疾病的供体细胞。方法通过细胞形态观察、MTT实验、克隆形成率、PCR检测、以及成脂、成骨、成软骨分化潜能检测等,研究MAPC培养条件下猴BMMSCs和hADSCs的特征,并用DMEM/LG和MAPC培养条件培养的hADSCs进行RCS大鼠视网膜下腔移植,通过视网膜电图（ERG）和TUNEL检测,判断细胞移植治疗对视功能及视网膜细胞凋亡的影响。结果与常规培养基相比,MAPC培养条件能促进猴BMMSCs增殖,细胞变小,但传2代后,细胞变得宽大扁平,出现衰老征象;然而,MAPC培养条件下的hADSCs细胞增殖能力及克隆形成率均增强,形成的克隆较大可稳定传10代以上,且具有成脂、成骨、成软骨的多向分化潜能,细胞表面标记物及细胞因子出现差异表达：CD140b、CD90、CD47、HGF和PEDF显著上调,CD73、CD105和IL-6显著下调。与对照组相比,移植DMEM/LG和MAPC培养条件培养的hADSCs（P4）3周后,RCS大鼠的B波波幅明显升高,外核层细胞凋亡明显减少。结论 MAPC培养条件培养的hADSCs显示出更好的视网膜神经保护作用,适合用于治疗视网膜退行性疾病。     

TGF-b1对骨髓间充质干细胞迁移力及 Snail表达的影响

采用密度梯度离心结合贴壁法分离、培养大鼠骨髓间充质干细胞(BMMSCs),用免疫荧光法对培养第3代的细胞进行鉴定.用改良的Transwell小室及MTT法检测不同浓度TGF- b1对细胞迁移力及细胞增殖的影响;流式细胞仪检测细胞凋亡;RT-PCR检测TGF-b1作用不同时间细胞snail、基质金属蛋白酶2(MMP-2)mRNA表达;免疫荧光和Western印迹检测snail表达情况.结果表明密度梯度离心结合贴壁法能有效分离、纯化大鼠BMMSCs,免疫荧光检测显示培养的细胞CD29、CD44表达阳性,而CD34、CD45表达阴性;外源性TGF-b1对BMMSCs迁移力的促进作用具有剂量依赖性,在2 ng/ml时达到最高.高浓度却抑制BMMSCs的迁移.在2 ng/ml TGF-b1刺激下,细胞凋亡明显降低,snail、MMP-2 mRNA及snail表达明显增高,但对细胞增殖无明显影响.通过研究TGF-b1对BMMSCs的迁移力的影响及作用机制,为体外调控BMMSCs高效迁移入脑从而发挥其修复神经损伤作用提供实验依据和理论基础.     

K562来源的外泌体对骨髓间充质干细胞造血和成骨基因表达的影响

目的 探讨K562细胞来源的外泌体(EXO)对骨髓间充质干细胞(BMMSCs)支持造血和成骨分化相关因子表达的影响.方法 利用超速离心法提取K562细胞培养上清中的EXO并进行鉴定.在体外,诱导BMMSCs的成骨分化,根据是否加入EXO分为3组:BMMSCs+PBS、BMMSCs+EXO(25μg/mL)、BMMSCs...     

与损伤神经细胞共育后小胶质细胞促进骨髓间充质干细胞神经保护功能

采用原代细胞培养法培养骨髓间充质干细胞(BMMSCs),以鼠小胶质细胞瘤细胞(BV2)和鼠嗜铬细胞瘤细胞(PC12)细胞株分别代替小胶质细胞和神经细胞进行传代培养,应用转移筛网进行BV2与正常或损伤PC12的共育后,考察BV2对BMMSCs的神经保护作用的影响。结果发现小胶质细胞(BV2)与损伤PC12共育后,能促进BMMSCs的神经保护作用,后者的上清液能降低受损PC12的凋亡率(35.9±13.5)%,同对照组(95.1±26.6)%相比差异有统计学意义(P<0.05),且BMMSCs上清液中bFGF升高达到(34.0±10.0)pg/ml,同对照组(20.3±7.1)pg/ml相比二者差异有统计学意义(P<0.05)。     

电离辐射及不同条件培养基诱发骨髓间充质干细胞基因组不稳定性的比较研究

为了探讨不同剂量电离辐射及其所致条件培养基对肺癌相关骨髓间充质干细胞(bone marrow mesenchy-mal stem cells,BMMSCs)基因组不稳定性的影响,以A549和人BMMSCs为研究对象,采用X射线辐射和条件培养基转移的方法建立辐射旁效应模型,检测基因组不稳定性相关的细胞克隆存活率、微核率、...     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.