间充质干细胞-透明质酸-多聚赖氨酸治疗脊髓损伤的实验研究

目的研究间充质干细胞—透明质酸—多聚赖氨酸复合物治疗脊髓损伤的可行性,评价其治疗效果并探讨其可能机制。方法从人骨髓中分离、培养人骨髓间充质干细胞（human bone marrow mesenchymal stem cell,hBMSC）;制作大鼠脊髓半横断模型,按照实验分组分别将hBMSC、透明质酸-多聚赖氨酸（hyaluronic acid-poly-L-lysine,HA-PLL）、hBMSC-HA-PLL复合物注入损伤区域,单纯损伤组作为对照。术后按照不同时间点评价损伤和移植后的大鼠运动功能。8周后杀死大鼠,观察不同移植组体内轴突和血管生长的情况,对不同细胞、材料及复合物移植对大鼠脊髓损伤修复效果进行评估。结果 hBMSC移植组和hBMSC-HA-PLL移植组的大鼠运动功能的改善显著好于单纯损伤及HA-PLL移植组。电镜结果证实复合物移植组可显著促进轴突和血管生长,新生的轴突和血管结构较为完整。结论 hBMSC具有促进神经功能恢复的作用,将其与HA-PLL相结合,可以促进大鼠脊髓损伤修复,其机制可能包括材料框架作用和hBMSC在体内对大鼠神经细胞的营养作用以及促进微血管的生成。     

干细胞生物药物研究进展

胚胎干细胞和成年干细胞经培养能产生更多干细胞也可定向分化成神经细胞、血细胞、肝细胞等特定类型的细胞。其中具有潜能的细胞可用来研究治疗帕金森病、糖尿病和脊髓损伤等疾病的生物药物。     

移植骨髓间充质干细胞源性神经元样细胞治疗大鼠脊髓损伤

目的:研究骨髓间充质干细胞源性神经元样细胞移植治疗成鼠脊髓损伤的可行性。方法:选取成年SD大鼠32只,两只用以提取骨髓间充质干细胞,其余被分为3组,其中细胞移植组10只,PBS缓冲液组10只,空白对照组10只。骨髓间充质干细胞分离传代培养并诱导成神经元样细胞后用Hoechst33342标记,损伤1周后采取静脉注射移植的方法移植于大鼠脊髓损伤区,移植六周后用免疫荧光方法检测细胞的存活及与宿主脊髓的整合情况。脊髓损伤后的1~6周对各组动物进行BBB评分,用SPSS12.0进行数据分析。结果:细胞移植组动物的BBB评分提高显著,于其他两组差异有统计学意义。细胞移植组免疫荧光显示,移植细胞在体内大量存活并桥接于脊髓损伤区的两端,存活的多数细胞神经元特异性标记物NSE、NF-200、星形胶质细胞特异性标记物GFAP表达呈阳性。结论:移植定向诱导的神经元样细胞有助于大鼠脊髓损伤后的功能恢复。     

骨髓间充质干细胞移植对急性脊髓损伤脱髓鞘病变的保护作用

骨髓间充质干细胞(Bone marrow mesenchymal stem cells,BMSCs)已被广泛应用于治疗脊髓损伤,但目前对其治疗机制了解甚少。BMSCs被移植至脊髓钳夹损伤模型大鼠,以研究其保护作用。通过LFB(Luxol fast blue)染色、锇酸染色、TUNEL(Td T-mediated d UTP nick-end labeling)染色和透射电镜对白质有髓神经纤维进行观察。免疫印迹检测BMSCs移植对脑源性神经营养因子(Brain derived neurotrophic factor,BDNF)和caspase 3蛋白表达的影响。通过脊髓损伤后1、7、14 d三个时间点移植BMSCs并进行后肢运动评分(Basso,beattie and bresnahan;BBB评分)和CNPase(2′,3′-cyclic-nucleotide 3′-phosphodiesterase)、髓鞘碱性蛋白(Myelin basic protein,MBP)、caspase 3蛋白水平的检测。免疫荧光观察BMSCs移植到受损脊髓后分化情况及CNPase-caspase 3~+共表达情况。骨髓间充质干细胞移植7 d后,部分移植的BMSCs可表达神经元和少突胶质细胞标记物,大鼠后肢运动能力和髓鞘超微结构特征均明显改善。骨髓间充质干细胞移植后BDNF蛋白表达水平增加,caspase 3蛋白表达水平则降低。相对于脊髓损伤后1 d和14 d,7 d移植BMSCs后MBP和CNPase蛋白表达水平最高;caspase 3蛋白表达水平则最低。骨髓间充质干细胞移植后CNPase-caspase 3~+细胞散在分布于脊髓白质。结果表明,急性脊髓损伤后,BMSCs移植到受损脊髓有分化为神经元和少突胶质细胞的倾向,并促进BDNF的分泌介导抗少突胶质细胞凋亡而对神经脱髓鞘病变有保护作用,且最佳移植时间为脊髓损伤后7 d。     

骨髓间充质干细胞移植修复大鼠半横断脊髓损伤

目的初步探讨骨髓间充质干细胞诱导为神经细胞,及其移植对大鼠脊髓半横断损伤神经功能恢复和运动的影响。方法贴壁培养法分离培养大鼠骨髓间充质干细胞(mesenchymal stem cells,MSCs),大鼠脊髓匀浆上清诱导第3代向神经细胞分化,经免疫组化鉴定分化后细胞的性质。制备大鼠半横断脊髓损伤模型,脊髓损伤局部注射BrdU标记诱导后的神经细胞。细胞移植5周后观察移植细胞在脊髓内存活分布情况。结果倒置显微镜下可见MSCs呈纺锤形和多角形,有1~2个核仁,经脊髓匀浆上清诱导后,发出数个细长突起,并交织成网,诱导后的细胞表达Nestin,可推测诱导后的细胞为MSCs源神经细胞。5周后移植的MSCs在宿主损伤脊髓内聚集并存活,表达MAP-2、NF、GFAP与对照组比较有统计学意义(P0.05)。大鼠运动功能较移植前有所改善。结论MSCs经脊髓匀浆上清诱导后移植治疗大鼠半横断脊髓损伤可使运动功能得到改善。     

治疗脊髓损伤之建立星形胶质细胞模型的研究进展

脊髓损伤(spinal cord injury,SCI)是一种极为复杂的破坏性疾病,一旦脊髓损伤发生,治疗棘手,对患者家庭、国家带来巨大的经济、社会负担。近年来,通过建立大鼠脊髓损伤细胞相关模型,对于脊髓损伤的病因病机治疗等方面有了进一步的认识,而星形胶质细胞模型的建立对脊髓损伤治疗有深远意义。研究发现,星形胶质细胞作为靶细胞通过血-脑脊液屏障直接或间接对脊髓损伤有双向调控作用。本文通过对近年来星形胶质细胞模型培养制备方案等研究进行总结,以期为建立一个客观化、定量化、可模拟化的星形胶质细胞模型提供指导对脊髓损伤的治疗提供新的思路。     

骨髓基质干细胞与雪旺细胞共培养移植治疗脊髓损伤的研究

脊髓损伤是严重的中枢神经系统疾病,脊髓损伤致使大量神经细胞缺失、凋亡,如何补充缺失的神经细胞,建立有利轴突再生的微环境成为脊髓损伤治疗的关键。雪旺细胞（schwann cells,SCs）分泌的多种神经营养因子,能维护神经元的存活及挽救凋亡的神经元。骨髓基质干细胞（bone marrow stromal cells,BMSCs）具有多向分化潜能,作为种子细胞替代缺失的神经元。     

生长因子基因治疗脊髓损伤的研究现状及其应用前景

基因治疗已成为当前生物医学中发展最快的领域之一,其基础研究和临床试验都展示出了巨大的前景,但是其对于中枢神经系统损伤的研究仍处于实验探索阶段。以脊髓损伤为例,近年来,细胞生长因子逐渐成为脊髓损伤治疗的突破点,而基因治疗脊髓损伤的基本策略是生长因子基因修饰受体细胞后,移植治疗脊髓损伤,利用生长因子基因治疗技术充分发挥生长因子效应促进神经再生。基因载体常用转染率高的病毒,受体细胞以神经干细胞、间充质干细胞为主。介绍了当前国际上基因治疗脊髓损伤的研究情况,阐述生长因子基因治疗对脊髓损伤的研究进展,并对其存在的问题和前景进行了分析和展望。     

缺氧预处理神经干细胞移植对大鼠急性脊髓损伤后神经胶质细胞凋亡及脊髓空洞形成的影响

目的:研究缺氧预处理神经干细胞(NSCs)移植对大鼠急性脊髓损伤(ASCI)后神经胶质细胞凋亡及脊髓空洞形成的影响。方法:将30只SD大鼠分为假手术对照组;脊髓损伤组;去铁敏组;普通NSCs组;缺氧预处理NSCs组。制成脊髓损伤模型,移植后观察脊髓神经胶质细胞凋亡情况及脊髓空洞形成情况。结果:经去铁敏缺氧预处理培养的NSCs与常规培养的NSCs无明显形态学变化。移植术后7d,缺氧预处理NSCs移植能显著减少脊髓损伤周围区神经胶质细胞的凋亡数量,减少脊髓空洞形成。结论:缺氧预处理NSCs移植能明显抑制大鼠急性脊髓损伤后神经胶质细胞凋亡,减少脊髓空洞的形成。     

脊髓损伤的病理改变及修复策略

脊髓损伤造成神经组织坏死,传导通路中断,损伤平面以下运动和感觉功能丧失,导致瘫痪甚至死亡.脊髓损伤的病理变化极其复杂,早期主要为分子基因水平的改变,亚急性期主要为细胞组织水平的变化.这些变化引发继发性损伤,致使组织坏死、神经元死亡、轴突断裂并形成由瘢痕组织包裹的囊性空洞,抑制轴突再生.目前临床上仅能通过手术减压或者使用药物对症干预,无法从根本上改善受损神经的功能.脊髓损伤后功能难以恢复有多方面的原因:炎症反应贯穿脊髓损伤全过程,炎症介质导致损伤区域的神经元及胶质细胞变性坏死,轴突因瓦勒变性而萎缩;神经元再生能力弱,轴突再生乏力,并且瘢痕组织导致轴突无法穿越损伤区域与远端的轴突形成联系.本文就脊髓损伤后的病理改变进行综述并探讨修复策略.     

Cell separation with horizontal cell electrophoresis under near-isopycnic conditions on a “density cushion”

This report describes an improvement made to the horizontal cell electrophoresis methodology. It involves using two liquid layers differing in density to produce an interface described as a "density cushion". The electrophoretic system that employed an anti-convective porous matrix to separate red blood cells (RBC) and charged dyes effectively was found to be unsuitable for some other mammalian cells. The "density cushion" method was found to be more versatile and applicable to studies on the separation of a variety of cell types. The experiments described show the differences between the electrophoretic mobilities of a human eosinophilic leukaemia cell line (Eol-1) and RBC, both with and without the modification of the cell surface properties.     

Cell electrophoresis — a method for cell separation and research into cell surface properties

In this paper, we discuss the application of various methods of cell electrophoresis in research into cell surface properties (analytical methods), and the separation of uniform cell subpopulations from cell mixtures (preparative methods). The emphasis is on the prospects of the development of simplified and versatile methodologies, i.e. microcapillary cell electrophoresis and horizontal cell electrophoresis under near-isopycnic conditions. New perspectives are considered on the use of analytical and preparative cell electrophoresis in research on cell differentiation, neoplastic transformation, cell-cell interactions and the biology of stem cells. Paper authored by participants of the international conference: XXXIV Winter School of the Faculty of Biochemistry, Biophysics and Biotechnology of Jagiellonian University, Zakopane, March 7–11, 2007, “The Cell and Its Environment”. Publication cost was covered by the organisers of this meeting.     

Polarization and Migration of Hematopoietic Stem and Progenitor Cells Rely on the RhoA/ROCK I Pathway and an Active Reorganization of the Microtubule Network

Understanding the physiological migration of hematopoietic progenitors is important, not only for basic stem cell research, but also in view of their therapeutic relevance. Here, we investigated the role of the Rho kinase pathway in the morphology and migration of hematopoietic progenitors using an ex vivo co-culture consisting of human primary CD34⁺ progenitors and mesenchymal stromal cells. The addition of the Rho kinase inhibitor Y-27632 led to the abolishment of the uropod and microvillar-like structures of hematopoietic progenitors, concomitant with a redistribution of proteins found therein (prominin-1 and ezrin). Y-27632-treated cells displayed a deficiency in migration. Time-lapse video microscopy revealed impairment of the rear pole retraction. Interestingly, the knockdown of ROCK I, but not ROCK II, using RNA interference (RNAi) was sufficient to cause the referred morphological and migrational changes. Unexpectedly, the addition of nocodazole to either Y-27632- or ROCK I RNAi-treated cells could restore their polarized morphology and migration suggesting an active role for the microtubule network in tail retraction. Finally, we could demonstrate using RNAi that RhoA, the upstream regulator of ROCK, is involved in these processes. Collectively, our data provide new insights regarding the role of RhoA/ROCK I and the microtubules in the migration of stem cells.     

Expanisns

Biochemical dissection of the “acid-growth” process of plant cell walls led to the isolation of a new class of wall loosening proteins, called expansins. These proteins affect the rheology of growing walls by permitting the microfibril-matrix network to slide, thereby enabling the wall to expand. Molecular sequence analysis suggests that expansins might have a cryptic glycosyl transferase activity, but biochemical results suggest that expansins disrupt noncovalent bonding between microfibrils and the matrix. Recent discoveries of a new expansin family and gene expression in fruit, meristerms and cotton fibers have enlarged our view of the developmental functions of this group of wall loosening proteins.     

酸性磷酸酶法检测体外培养细胞数

利用小鼠成纤维细胞系(NIH3T3)、小鼠骨髓瘤细胞系(SP2/0)、人大肠癌细胞系(LO-VO)和人白血病细胞系(K562),评价酸性磷酸酶(APA)法用于检测体外各类型细胞的增殖和杀伤作用。用直线回归分析光吸收度与每孔活细胞数的关系。结果表明,APA法能准确地反映检测的活细胞数(相关系数均>0.99)。本方法不仅能很好地检测表皮生长因子对细胞的增殖作用,也能够检测顺铂对体外细胞的杀伤作用。结果表明APA法简单、灵敏,可以用于上皮和间质等贴壁和悬浮生长的细胞计数。     

An overview of the KIN1/PAR-1/MARK kinase family

Members of the KIN1/PAR-1/MARK kinase family are conserved from yeast to humans and share a similar primary structural organization. Several kinases of this family appear to be at the crossroads of various biological functions including cell polarity, cell cycle control, intracellular signalisation, microtubules stability and protein stability. Here we present an overview of known roles of KIN1/PAR-1/MARK kinases including pEg3 a newly identified member which is regulated during the cell cycle and is a potential regulator of the cell cycle progression. Some common modes of action can be deciphered for this protein kinase family.     

犬皮肤成纤维细胞的分离、培养及鉴定

目的探索和建立适用于犬皮肤成纤维细胞的体外分离、培养及鉴定的技术方法。方法采用组织贴块培养法和胰蛋白酶、胶原酶Ⅰ联合消化法对犬皮肤成纤维细胞进行体外培养、传代。并对所培养的细胞进行倒置显微镜观察和苏木素-伊红染色,观察成纤维细胞形态,并对培养细胞行波形蛋白免疫荧光染色。结果倒置相差显微镜下可见长梭形细胞生长,苏木素-伊红染色可见细胞呈漩涡状、平行排列,第5代细胞免疫荧光检测波形蛋白(vimentin)表达阳性。结论建立了高效快速分离和稳定培养成纤维细胞的方法,为诱导犬心房纤维化提供了充足的种子细胞。     

A Scalable Approach to Prevent Teratoma Formation of Human Embryonic Stem Cells

As the renewable source of all cell types in the body, human embryonic stem cells (hESCs) hold great promise for human cell therapy. However, one major bottleneck that hinders the clinic application of hESCs is that hESCs remaining with their differentiated derivatives pose cancer risk by forming teratomas after transplantation. NANOG is a critical pluripotency factor specifically expressed in hESCs but rarely in their differentiated derivatives. By introducing a hyperactive variant of herpes simplex virus thymidine kinase gene into the 3′-untranslated region of the endogenous NANOG gene of hESCs through homologous recombination, we developed a safe and highly scalable approach to efficiently eliminate the teratoma risk associated with hESCs without apparent negative impact on their differentiated cell types. As thymidine kinase is widely used in human gene therapy trials and is the therapeutic target of U. S. Food and Drug Administration-approved drugs, our strategy could be effectively applied to the clinic development of hESC-based human cell therapy.     

The plant cell body: a cytoskeletal tool for cellular development and morphogenesis

Summary Certain aspects of cellular behaviour in relation to growth and development of plants can be understood in terms of the cell body concept proposed by Daniel Mazia in 1993. During the interphase of the mitotic cell cycle, the plant cell body is held to consist of a nucleus and a perinuclear microtubule-organizing centre from which microtubules radiate into the cytoplasm. During mitosis and cytokinesis in meristematic cells, and also during the period of growth in post-mitotic cells immediately beyond the meristem, the plant cell body undergoes various characteristic morphological transformations, many of which are proposed as being related to changing structural connections with the actin-based component of the cytoskeleton and with specialized, plasma-membrane-associated sites at the cell periphery. In post-mitotic cells, these transformations of the plant cell body coincide with, and probably provide conditions for, the various pathways of development which such cells follow. They are also responsible, for the acquisition of new cellular polarities. Events in which the plant cell body participates include the formation of a mitotic spindle, phragmoplast, and new cell division wall, the rearrangement of a diffuse type of cell wall growth into tip growth (as occurs, e.g., during the initiation and subsequent development of root hairs), and the growth and division that occurs in reactivated vacuolate cells. If more evidence can be marshalled in support of the existence and properties of the plant cell body, then this concept could prove useful in interpreting the cytological bases of a range of developmental events in plants.Abbreviations CMT cortical microtubule - EMT endoplasmic microtubule - ER endoplasmic reticulum - MF microfilament - MT microtubule - MTOC microtubule-organizing centre - PPB preprophase band (of microtubules) - QC quiescent centre - VSC vesicle supply centre     

Molecular basis for T cell response induced by altered peptide ligand of type II collagen

Mounting evidence from animal models has demonstrated that alterations in peptide-MHC interactions with the T cell receptor (TCR) can lead to dramatically different T cell outcomes. We have developed an altered peptide ligand of type II collagen, referred to as A9, which differentially regulates TCR signaling in murine T cells leading to suppression of arthritis in the experimental model of collagen-induced arthritis. This study delineates the T cell signaling pathway used by T cells stimulated by the A9·I-A(q) complex. We have found that T cells activated by A9 bypass the requirement for Zap-70 and CD3-ζ and signal via FcRγ and Syk. Using collagen-specific T cell hybridomas engineered to overexpress either Syk, Zap-70, TCR-FcRγ, or CD3-ζ, we demonstrate that A9·I-A(q) preferentially activates FcRγ/Syk but not CD3-ζ/Zap-70. Moreover, a genetic absence of Syk or FcRγ significantly reduces the altered peptide ligand induction of the nuclear factor GATA3. By dissecting the molecular mechanism of A9-induced T cell signaling we have defined a new alternate pathway that is dependent upon FcRγ and Syk to secrete immunoregulatory cytokines. Given the interest in using Syk inhibitors to treat patients with rheumatoid arthritis, understanding this pathway may be critical for the proper application of this therapy.