成年大鼠脑膜原代组织干细胞特性细胞的分离及神经诱导分化研究

目的 分离并检测成年大鼠脑膜组织中具有干细胞特性的细胞亚群,探讨其诱导成神经细胞的能力.方法 自成年大鼠活体分离、剪取脑膜经胰酶消化制成细胞悬液,接种于培养皿,用无血清的特殊培养基培养,动态观察脑膜细胞克隆球的形成及分化过程,并用巢蛋白（Nestin）、表面抗原CD133抗体进行免疫荧光染色,对阳性细胞进行表观遗传学鉴定.分离的脑膜细胞经曲古抑菌素A（TSA）诱导培养基分别诱导分化后检测脑膜细胞向神经细胞分化成熟程度,用免疫印迹法（westen blotting）检测诱导分化后脑膜细胞内成熟神经细胞相关标志性蛋白--高分子量神经丝蛋白（NF-200）、神经元蛋白（BM88）的表达情况.结果 成年大鼠脑膜组织体外培养时不同类型细胞的贴壁时间有差异,具有干细胞特性细胞呈球形,黏着在首先贴壁的扁平基底细胞上分裂形成克隆球,克隆球细胞Nestin、CD133免疫荧光染色阳性.诱导分化后NF-200、BM88有明显表达,表明经诱导分化后脑膜细胞可分化为神经细胞.结论 活体分离成年大鼠脑膜组织部分细胞体外培养具有干细胞特性,并可向神经细胞方向分化.     

人骨髓基质干细胞体外分离培养的优化及定向分化的调控

目的 通过改进人骨髓基质干细胞（hBMSCs）的体外培养和定向诱导为神经细胞的方法,以获得纯化hBMSCs以及阳性率更高的神经细胞。方法 采用Percoll-Paque液（1．073g／m1）分离hBMSCs,Mensen Cult培养基体外培养扩增,流式细胞仪检测纯化率。至P3代加入特定组合诱导剂进行定向诱导分化,观察hBMSCs分化为神经细胞的形态学变化,免疫组化和免疫荧光检测特异性神经元烯醇化酶（NSE）、神经丝蛋白（NF）、胶质纤维酸性蛋白（GFAP）阳性细胞数。结果Mensen Cult培养hBMSCs的扩增速度快,纯化率高;在加入特定诱导剂后细胞出现胞体收缩、突起伸出等神经细胞的形态改变,NSE、NF、GFAP均有不同程度阳性率。结论 Mensen Cult是一种较为优秀的hBMSCs体外培养基,而且我们使用的诱导配方效果确切。     

不同细胞因子体外诱导神经干细胞向神经细胞分化的研究

目的观察碱性纤维母细胞生长因子、白血病抑制因子、脑源性神经营养因子及不同组合对成年SD大鼠脑神经干细胞在体外分化为神经细胞的作用。方法用含碱性纤维母细胞生长因子（bFGF）、B27的无血清细胞培养技术体外培养成年SD大鼠脑神经干细胞,单细胞克隆后行Nestin免疫细胞化学染色;根据培养液中所加营养因子的不同将单细胞克隆传代细胞分为5组培养：bFGF、LIF、BDNF、bFGF＋LIF、bFGF＋BDNF组,此5组细胞培养1周,进行NSE免疫细胞化学染色,计数阳性细胞比例后进行统计学分析。结果单细胞克隆培养后克隆球细胞表达Nestin;与bFGF组、LIF组、BDNF组相比,bFGF＋BDNF组和bFGF＋LIF组神经干细胞分化为神经细胞的比例较高（P〈0．01）,其中bFGF＋BDNF组神经细胞的比例最高。结论在bFGF培养条件下,BDNF促进成年SD大鼠脑神经干细胞向神经细胞分化的能力高于LIF。     

人胚胎神经干细胞体外培养及其增殖与分化的研究

目的 建立神经干细胞分离、培养及分化的鉴定技术，观察神经干细胞增殖、分化的特点。方法 从人胚胎海马区分离神经干细胞，采用无血清培养基，进行体外扩增培养、传代。采用免疫细胞化学法鉴定神经干细胞和分化的神经细胞；利用流式细胞仪和细胞生长曲线检测神经干细胞的增殖能力。结果 从人胚胎脑海马区分离的细胞具有增殖和多向分化潜能，可进行传代培养，获得的细胞团中大部分为nestin表达阳性细胞。贴壁分化后可以出现NSE、GFAP表达阳性的细胞。结论 用上述方法分离培养的细胞能表达nestin蛋白，具有自我更新和增殖能力，并具有向神经元、星形胶质细胞分化的潜能，具备神经干细胞的特征，可用于细胞移植等相关研究。     

大鼠神经干细胞的分离培养和分化鉴定

目的建立神经干细胞分离、培养和分化鉴定技术。观察神经干细胞生长、增殖特点。方法利用无血清培养,从胚胎大鼠海马、纹状体等区分离神经干细胞,进行体外扩增培养、传代观察。采用荧光免疫细胞化学检测技术,观察鉴定神经干细胞及其分化结果。结果从胚胎大鼠海马、纹状体等区分离的细胞具有增殖能力,可进行传代培养,获得的细胞克隆中有巢蛋白(nestin)表达阳性细胞,显微镜下观察见典型的干细胞特征。分化为3种神经细胞类型:神经元、胶质细胞、少突胶质细胞。结论用上述方法分离培养的神经干细胞具有自我更新和增殖能力,通过鉴定确为神经干细胞,并经过分化鉴定确认。     

人胚神经干细胞分离培养与鉴定方法

目的:建立神经干细胞(NSCs)实验室分离、培养方法,为NSCs移植提供细胞源.方法:取4月龄(±15 天)正常孕妇水囊引产胎儿大脑纹状体区组织分离神经干细胞,培养于含碱性成纤维细胞生长因子(bFGF)和B27的无血清培养基;同时利用单细胞克隆技术进行连续传代培养;利用形态学观察和免疫荧光技术检测神经上皮干细胞蛋白Nestin抗原的表达来鉴定神经干细胞.结果:体外培养的干细胞在bFGF和B27培养基中可不断增殖形成细胞球,并出现少量细胞分化.单细胞培养4天即开始分裂,同时伴有个别细胞分化;出现大量神经球一般为15天;分化的细胞在30天开始分解,50天左右基本消失.细胞培养3个月(每月补液1次)仍具有分裂增殖能力.单细胞克隆可连续传代10次,仍具增殖分化能力.液氮冻存6个月的细胞复苏后仍具增殖分化能力.单细胞克隆传代增殖的细胞球经Nestin免疫荧光鉴定,呈阳性结果,证实其胚胎源性.结论:采用bFGF和B27的无血清培养基能促进神经干细胞连续稳定增殖,并有少量分化,细胞体外培养3个月、克隆连续传代10次情况下的细胞仍具有神经干细胞特性.     

人胚神经干细胞分离培养与鉴定方法

目的 :建立神经干细胞 (NSCs)实验室分离、培养方法 ,为NSCs移植提供细胞源。方法 :取 4月龄 (± 15天 )正常孕妇水囊引产胎儿大脑纹状体区组织分离神经干细胞 ,培养于含碱性成纤维细胞生长因子 (bFGF)和B2 7的无血清培养基 ;同时利用单细胞克隆技术进行连续传代培养 ;利用形态学观察和免疫荧光技术检测神经上皮干细胞蛋白Nestin抗原的表达来鉴定神经干细胞。结果 :体外培养的干细胞在bFGF和B2 7培养基中可不断增殖形成细胞球 ,并出现少量细胞分化。单细胞培养 4天即开始分裂 ,同时伴有个别细胞分化 ;出现大量神经球一般为 15天 ;分化的细胞在 3 0天开始分解 ,5 0天左右基本消失。细胞培养 3个月 (每月补液 1次 )仍具有分裂增殖能力。单细胞克隆可连续传代 10次 ,仍具增殖分化能力。液氮冻存 6个月的细胞复苏后仍具增殖分化能力。单细胞克隆传代增殖的细胞球经Nestin免疫荧光鉴定 ,呈阳性结果 ,证实其胚胎源性。结论 :采用bFGF和B2 7的无血清培养基能促进神经干细胞连续稳定增殖 ,并有少量分化 ,细胞体外培养 3个月、克隆连续传代 10次情况下的细胞仍具有神经干细胞特性     

Feridex标记胎盘来源的间充质干细胞分化为神经干细胞的实验研究

目的分离胎盘组织来源的间充质干细胞并诱导分化为神经干细胞,以期找到能成功标记神经干细胞的方法。方法将胎盘组织剪碎后消化、培养,加入神经干细胞诱导因子10ng/mL表皮生长因子（EGF）＋10ng/mL重组人碱性成纤维生长因子（bFGF）＋DMEM/F12,并分别添加相应浓度的血清,预诱导3d后加入DMEM/F12＋0.1μmol/L全反式维甲酸（RA）,10ng/mL胶质细胞系源性神经营养因子（GDNF）＋10ng/mL脑源性神经营养因子（BDNF）进行正式诱导7d。结果诱导10d后用Feridex标记诱导后的细胞,普鲁士蓝染色显示90%以上的干细胞胞质内出现细小的蓝色铁颗粒,Nestin染色显示阳性。结论胎盘来源的间充质干细胞能成功诱导为神经干细胞,且Feridex可成功标记诱导后的细胞。     

去分化肌肉干细胞神经分化潜能的探讨

目的探讨去分化肌肉干细胞经条件培养诱导,具有神经干细胞性质并分化为终末神经细胞的潜能。方法依次用神经干细胞增殖及神经细胞分化条件培养基,对去分化肌肉干细胞进行体外诱导,促使其向神经干细胞转变以及向终末神经细胞分化,并通过形态学、免疫细胞化学、RT-PCR等实验手段研究其性质并加以鉴定。结果 (1)去分化肌肉干细胞在神经干细胞增殖条件培养基诱导下,可形成神经球,EdU标记阳性,抗Nestin、Neurofilament-m(NFm)、GFAP、CNPase阳性;Myogenin表达水平下调,而Nestin、Sca-1表达上调;(2)经神经细胞分化条件培养基诱导,神经球细胞可分化为形态学上典型的、抗NFm阳性神经元,以及抗GFAP、CNPase阳性神经胶质细胞。结论去分化肌肉干细胞具有神经系的多分化潜能。     

胶质瘤细胞诱导神经干细胞迁移作用的实验研究

目的观察胶质瘤细胞在体外培养条件下对神经干细胞是否有诱导迁移的作用。方法①从新生1～2dSD大鼠脑皮层分离培养神经干细胞,进行神经干细胞及其增殖能力鉴定。②胶质瘤细胞与神经干细胞限定区域联合培养,观察神经干细胞的生长及其形态学变化。结果①所获得神经细胞球Nestin染色阳性,传代神经细胞球抗BrdU染色阳性。②可观察到神经干细胞球周围长出细胞突起,在靠近胶质瘤细胞的一侧,细胞突起的密度及长度均大于其他方向上的突起并且可见部分干细胞向胶质瘤细胞方向的移动。结论胶质瘤细胞在体外对神经干细胞有诱导迁移作用。     

Correlation of proliferation,TGF-β3 promoter methylation,and Smad signaling in MEPM cells during the development of ATRA-induced cleft palate

Mesenchymal cell proliferation is one of the processes in shelf outgrowth. Both all-trans retinoic acid (atRA) and transforming growth factor-β3 (TGF-β3) play an important role in mouse embryonic palate mesenchymal (MEPM) cell proliferation. The cellular effects of TGF-β are mediated by Smad-dependent or Smad-independent pathways. In the present study, we demonstrate that atRA promotes TGF-β3 promoter demethylation and protein expression, but can cause depression of mesenchymal cell proliferation, especially at embryonic day 14 (E14). Moreover, the inhibition of MEPM cell proliferation by atRA results in the downregulation of Smad signaling mediated by transforming growth interacting factor (TGIF). We speculate that the effects of atRA on MEPM cell proliferation may be mediated by Smad pathways, which are regulated by TGIF but are not related to TGF-β3 expression. Finally, the cellular effects of TGF-β3 on MEPM cell proliferation may be mediated by Smad-independent pathways.     

Induction of cell-cycle arrest by all-trans retinoic acid in mouse embryonic palatal mesenchymal (MEPM) cells.

all-trans retinoic acid (atRA), the oxidative metabolite of vitamin A, is essential for normal embryonic development. Also, high levels of atRA are teratogenic in many species and can effectively induce cleft palate in the mouse. Most cleft palate resulted from the failed fusion of secondary palate shelves, and maintenance of the normal cell proliferation is important in this process of shelf growth. To clarify the mechanism by which atRA causes cleft palate, we investigated the effect of atRA on proliferation activity and cell cycle distribution in mouse embryonic palatal mesenchymal (MEPM) cells. atRA inhibited the growth of MEPM cells by inducing apoptosis in a dose-dependent manner. atRA also caused a G1 block in the cell cycle with an increase in the proportion of cells in G0/G1 and a decrease in the proportion of cells in S phase, as determined by flow cytometry. We next investigated the effects of atRA on molecules that regulate the G1 to S phase transition. These studies demonstrated that atRA inhibited expression of cyclins D and E at the protein level. Furthermore, atRA treatment reduced phosphorylated Rb and decreased cdk2 and cdk4 kinase activity. These data suggest that atRA had antiproliferative activity by modulating G1/S cell cycle regulators and by inhibition of Rb phosphorylation in MEPM cells, which might account for the pathogenesis of cleft palate induced by retinoic acid.     

肿瘤细胞来源胞外体的分离鉴定与功能检测

目的:分离提纯和电镜鉴定乳腺癌细胞系MCF-7细胞分泌的胞外体,并观察其对淋巴细胞增殖的影响.方法: 将细胞培养上清进行分步离心、浓缩、密度梯度离心获得纯化后的胞外体,并对胞外体进行透射电镜鉴定.将分离纯化的胞外体加入含有IL-2的淋巴细胞培养体系中,用MTT试验计算淋巴细胞的增殖率,观察胞外体对淋巴细胞增殖的影响.结果:从2×10~7个细胞可获得20 mL纯化的胞外体,测得其总蛋白浓度为(1.84±0.01) g/L,经电镜鉴定MCF-7细胞来源的胞外体直径为55～70 nm,为有膜包裹的囊泡状结构,大小较为均一,形态特征与观察到的多泡体的内部囊泡的大小和形态是一致的.MTT试验显示它能够抑制IL-2诱导的淋巴细胞增殖,并且随剂量增加抑制作用增强.结论:肿瘤细胞来源的胞外体可通过细胞培养上清分步离心浓缩纯化得到,其不仅具有胞外体的形态学特征,同时可对IL-2诱导的淋巴细胞增殖产生剂量依赖性的抑制作用.     

Enhanced skin regeneration by nanoegg formulation of all-trans retinoic acid

All-trans retinoic acid (atRA) which could smooth wrinkles and produce less pigmented skin after a few months of treatment has been studied in research into topical treatments for a potent inhibitor of new melanin production. However, the clinical responses of commercial atRA cream predominantly comprise severe inflammation. We report a novel nanotechnology "nanoegg" system giving improved effects of atRA self-assembly which were coated by CaCO3. Dorsal areas of hairless mouse and porcine skin were employed for administration of nanoegg ointment and commercial products. The mRNA for heparin-binding epidermal growth factor-like growth factor (HB-EGF) from tissues was measured by a real-time PCR method. All tissues were stained for detection of hyaluronate and the thickness of the epidermis. A clinical trial in humans was carried out at St. Marianna University in Japan. As a result, the irritation and inflammation associated with atRA molecules were substantially reduced. The physicochemical instability of atRA was also dramatically improved. Furthermore, nanoegg enhanced marked expression of mRNA for HB-EGF from keratinocytes, which is known as one of the markers of keratinocyte turnover. Also, production of hyaluronate was surprisingly in the intercellular spaces of the basal and spinous cell layers 2 days after treatment. Even at the low concentration of atRA in the nanoegg system, the proliferation and differentiation of keratinocyte was somewhat enhanced. A nanoegg may thus not only prevent adverse effects, but also markedly enhance the main effect.     

Three conazoles increase hepatic microsomal retinoic acid metabolism and decrease mouse hepatic retinoic acid levels in vivo

Conazoles are fungicides used in agriculture and as pharmaceuticals. In a previous toxicogenomic study of triazole-containing conazoles we found gene expression changes consistent with the alteration of the metabolism of all trans-retinoic acid (atRA), a vitamin A metabolite with cancer-preventative properties (Ward et al., Toxicol. Pathol. 2006; 34:863-78). The goals of this study were to examine effects of propiconazole, triadimefon, and myclobutanil, three triazole-containing conazoles, on the microsomal metabolism of atRA, the associated hepatic cytochrome P450 (P450) enzyme(s) involved in atRA metabolism, and their effects on hepatic atRA levels in vivo. The in vitro metabolism of atRA was quantitatively measured in liver microsomes from male CD-1 mice following four daily intraperitoneal injections of propiconazole (210 mg/kg/d), triadimefon (257 mg/kg/d) or myclobutanil (270 mg/kg/d). The formation of both 4-hydroxy-atRA and 4-oxo-atRA were significantly increased by all three conazoles. Propiconazole-induced microsomes possessed slightly greater metabolizing activities compared to myclobutanil-induced microsomes. Both propiconazole and triadimefon treatment induced greater formation of 4-hydroxy-atRA compared to myclobutanil treatment. Chemical and immuno-inhibition metabolism studies suggested that Cyp26a1, Cyp2b, and Cyp3a, but not Cyp1a1 proteins were involved in atRA metabolism. Cyp2b10/20 and Cyp3a11 genes were significantly over-expressed in the livers of both triadimefon- and propiconazole-treated mice while Cyp26a1, Cyp2c65 and Cyp1a2 genes were over-expressed in the livers of either triadimefon- or propiconazole-treated mice, and Cyp2b10/20 and Cyp3a13 genes were over-expressed in the livers of myclobutanil-treated mice. Western blot analyses indicated conazole induced-increases in Cyp2b and Cyp3a proteins. All three conazoles decreased hepatic atRA tissue levels ranging from 45-67%. The possible implications of these changes in hepatic atRA levels on cell proliferation in the mouse tumorigenesis process are discussed.     

Protection of acute GVHD by all-trans retinoic acid through suppression of T cell expansion and induction of regulatory T cells through IL-2 signaling

All-trans retinoic acid (atRA), the active derivative of vitamin A, has been shown to regulate Treg and T effector cell differentiation. However, the potential use of atRA as a treatment for acute graft-verse-host disease (aGVHD) has not been realized. Here we studied the ability of atRA to prevent and treat acute-GVHD in the B6-to-F1(D2B6F1) murine model. Our results showed that atRA consistently displayed a potent ability to control aGVHD development and reduce mortality by suppressing the expansion of donor T cells and inhibiting cytokine expression from donor CD8 cells. Interestingly, CD4⁺Foxp3⁺ regulatory T cells were markedly increased in the spleens of atRA-treated mice. In vitro treatment with atRA inhibited T cell proliferation in a dose-dependent manner. Injection of an anti-IL-2 antibody impaired the protection by atRA in aGVHD. Therefore, these results strongly implicate atRA as a novel therapeutic strategy for controlling aGVHD progression and treating other inflammatory diseases.     

Augmentation of all‐trans‐retinoic acid concentration in plasma by preventing inflammation responses induced by atRA‐loaded microspheres with concurrent treatment of dexamethasone

All‐trans retinoic acid (atRA)‐loaded microspheres severely induce inflammatory responses after microsphere implantation. Fibroblasts and a thick band of fibrous capsule resulting from the inflammatory responses could hamper drug permeation to the bloodstream because fibroblasts actively metabolize atRA into polar metabolites and the thick fibrous capsule acts as a diffusion barrier. In the present study, we investigated whether the fibroblast proliferation and collagen deposition induced by atRA released from microspheres might affect the atRA concentration in plasma and atRA metabolism with or without treatment of dexamethasone as an anti‐inflammatory drug. After subcutaneous injection of atRA‐loaded microspheres in rats, it was observed that atRA‐loaded microspheres induced severe inflammatory responses and stimulated fibroblast proliferation and collagen deposition in fibrous capsules. On the other hand, the orally treated dexamethasone effectively prevented inflammatory responses in a dose‐dependent manner and suppressed about 49% of the number of fibroblasts and collagen deposition in fibrous capsules at 14 days. In addition, after the treatment of dexamethasone, the atRA concentration in plasma was increased, and its metabolism was decreased approximately by 40% at 7 days, compared to the group treated alone with atRA‐loaded microspheres. In conclusion, the concurrent treatment of dexmethasone with atRA‐loaded microspheres could prevent inflammatory responses and metabolism of atRA, thereby maintaining the atRA concentration in plasma for longer periods in the therapeutic range. Drug Dev. Res. 61:197–206, 2004. © 2004 Wiley‐Liss, Inc.     

beta-Cryptoxanthin, a novel natural RAR ligand, induces ATP-binding cassette transporters in macrophages

Despite its serious adverse effects, recent accumulating evidence suggests that a physiological retinoic acid receptor (RAR) agonist, all-trans retinoic acid (atRA), exhibits preventive effects on atherogenesis. Therefore, the present study was designed to explore novel natural RAR ligands with anti-atherogenic effects in order to identify and develop a drug without severe side effects. Among xanthophylls and carotenoids studied, beta-cryptoxanthin and lutein exhibited RAR ligand activity in yeast two-hybrid system that was found to be completely abolished by the RAR pan-antagonist LE540. Furthermore, these molecules can bind the RAR ligand-binding domain in the CoA-BAP system but not RXR ligand-binding domain. These results indicate that both beta-cryptoxanthin and lutein serve as ligands for RAR, but not RXR, although their binding affinity was three orders of magnitude lower than that of atRA. Additionally, when applied to macrophages, beta-cryptoxanthin indeed was found to induce the ATP-binding cassette transporter A1 (ABCA1) and ABCG1 mRNAs, which exert anti-atherosclerotic effects by preventing cholesteryl ester accumulation in macrophages. The induction of ABCA1 proteins by beta-cryptoxanthin as well as atRA was abrogated by LE540. In summary, beta-cryptoxanthin appears to be more an efficient provitamin A source than other carotenoids and xanthophylls including beta-carotene, since beta-cryptoxanthin can act not only as a RAR agonist but also a source of vitamin A. Taking into account that the pharmacodynamics difference between beta-cryptoxanthin and atRA, beta-cryptoxanthin appears to exert beneficial effects on atherogenesis through RAR activation in the manner different from atRA.     

瑞香狼毒水提物小鼠的药物血清对K562细胞增殖的影响

目的 :研究瑞香狼毒 (SCA )抗癌作用机理。方法 :小鼠SCA灌胃给药后采集血清 ,处理体外培养的人红白血病K562细胞 ,测定其MTT转化及克隆形成率。结果 :SCA小鼠药物血清显著降低K562细胞MTT转化率和克隆形成率 ,并与给药剂量呈正相关 ,给药2h～4h时的药物血清表现出更强的抑制肿瘤细胞增殖作用。结论 :口服SCA后机体吸收入血的有效成分的直接抑制癌细胞增殖作用可能是其重要抗癌机理之一