经鼻导入rhG—CSF后脑梗死大鼠内源性神经干细胞的增殖与迁移

目的 探讨人重组粒细胞集落刺激因子（rhG-CSF）经鼻靶向中枢给药对脑梗死大鼠内源性神经干细胞增殖与迁移的调节作用。方法线栓法制作大脑中动脉阻塞模型（MCAO）,皮下或鼻腔给予rhG-CSF（60μg／kg）。运用5-溴脱氧尿苷嘧啶（BrdU）标记及免疫组织化学法检测局灶性脑梗死大鼠室管膜及脑室下层（SVZ）神经干细胞的增殖。结果正常组及假手术对照组大鼠SVZ区域散在少量BrdU阳性细胞;术后7d和14d,脑梗死组大鼠SVZ区BrdU阳性细胞数明显增加;rhG-CSF组BrdU阳性细胞数进一步增加;经鼻给药组的BrdU阳性细胞数明显高于相应时间点的皮下用药组（P〈0．01）。结论rhG-CSF鼻腔给药可以促进脑梗死后大鼠内源性神经干细胞的增殖和靶向迁移。     

Regulation of human hemopoietic stem cell proliferation by syngeneic thymus-derived lymphocytes.

Viable T lymphocytes stimulate the proliferation of human syngeneic hemopoietic stem cells, but not influence their differentiation. The biological significance of this activity is discussed and its possible physiological role in the regulation of hemopoiesis is considered.     

毒胡萝卜素对ReNcell CX人神经干细胞存活、增殖和凋亡的影响

目的观察毒胡萝卜素对ReNcell CX人神经干细胞存活、增殖和凋亡的影响。方法将ReNcell CX人神经干细胞分为两组,实验组分别加入10、20、50、100 nM毒胡萝卜素,干预6 h;对照组不加任何药物。采用分光光度计法测量两组乳酸脱氢酶(LDH)水平,免疫荧光显微镜下观测细胞增殖情况及Caspase-3水平。结果实验组LDH、Caspase-3水平明显高于对照组,细胞增殖率明显低于对照组,且均呈剂量依赖性,P<0.05或<0.01。结论毒胡萝卜素抑制神经干细胞存活和增殖;其机制可能为激活Caspase-3释放,促进神经干细胞凋亡。     

Reelin function in neural stem cell biology

In the adult brain, neural stem cells (NSC) must migrate to express their neuroplastic potential. The addition of recombinant reelin to human NSC (HNSC) cultures facilitates neuronal retraction in the neurospheroid. Because we detected reelin, alpha3-integrin receptor subunits, and disabled-1 immunoreactivity in HNSC cultures, it is possible that integrin-mediated reelin signal transduction is operative in these cultures. To investigate whether reelin is important in the regulation of NSC migration, we injected HNSCs into the lateral ventricle of null reeler and wild-type mice. Four weeks after transplantation, we detected symmetrical migration and extensive neuronal and glial differentiation of transplanted HNSCs in wild-type, but not in reeler mice. In reeler mice, most of the injected HNSCs failed to migrate or to display the typical differentiation pattern. However, a subpopulation of transplanted HNSCs expressing reelin did show a pattern of chain migration in the reeler mouse cortex. We also analyzed the endogenous NSC population in the reeler mouse using bromodeoxyuridine injections. In reeler mice, the endogenous NSC population in the hippocampus and olfactory bulb was significantly reduced compared with wild-type mice; in contrast, endogenous NSCs expressed in the subventricular zonewere preserved. Hence, it seems likely that the lack of endogenous reelin may have disrupted the migration of the NSCs that had proliferated in the SVZ. We suggest that a possible inhibition of NSC migration in psychiatric patients with a reelin deficit may be a potential problem in successful NSC transplantation in these patients.     

Betacellulin promotes cell proliferation in the neural stem cell niche and stimulates neurogenesis

Neural stem cells (NSCs) reside in specialized niches in the adult mammalian brain, including the subventricular zone and the dentate gyrus, which act to control NSC behavior. Among other cell types within these niches, NSCs are found in close proximity to blood vessels. We carried out an analysis of the interaction between endothelial cells and NSCs, and show that betacellulin (BTC), a member of the EGF family and one of several signaling molecules made by the former, induces NSC proliferation and prevents spontaneous differentiation in culture. When infused into the lateral ventricle, BTC induces expansion of NSCs and neuroblasts, and promotes neurogenesis in the olfactory bulb and dentate gyrus, whereas specific blocking antibodies reduce the number of stem/progenitor cells. BTC-null mice are less able to regenerate neuroblast numbers compared with WT littermates following depletion of proliferating cells using cytosine-β-d-arabinofuranoside. BTC acts via both the EGF receptor, located on NSCs, and ErbB4, located on neuroblasts, with the latter explaining why its effects are distinct from those of EGF itself. Our results suggest that BTC could be a good candidate to aid regenerative therapies.     

shR-377联合细胞因子诱导人脂肪间充质干细胞向神经干细胞定向分化

目的探索sh R-377联合细胞因子诱导人脂肪间充质干细胞(HADMSCs)向神经干细胞(NSCs)定向分化。方法采用吸脂术获取健康青年人腹部大网膜脂肪组织,胶原酶消化法分离HADMSCs,行表型鉴定和细胞周期检测。sh R-377转染第三代HADMSCs,48 h后流式检测nestin表达率,72 h后行RT-q PCR和免疫细胞化学测定nestin和musashi,并对转化后细胞增殖培养分析。结果流式结果显示HADMSCs表面标志CD45及CD117表达呈阴性,CD29及CD44呈阳性,诱导24 h后nestin表达率为(64.6±3.2%);RT-q PCR结果表明诱导72 h后神经干样细胞球nestin、musashi表达阳性,免疫细胞化学染色可见nestin染色阳性。神经干样细胞球增殖培养7 d可见多个克隆球。神经干样细胞球进一步分化培养,可见到很明显的细长突触,双极或多极神经元样形态。结论 sh R-377联合细胞因子的诱导方法可以使HADMSCs定向分化为NSCs,诱导时间约48 h。转化时间和转化率比传统方法有较大提高,为体外大量获得NSCs提供了实验依据。     

Melatonin enhances neural stem cell differentiation and engraftment by increasing mitochondrial function

Neural stem cells (NSCs) are regarded as a promising therapeutic approach to protecting and restoring damaged neurons in neurodegenerative diseases (NDs) such as Parkinson's disease and Alzheimer's disease (PD and AD, respectively). However, new research suggests that NSC differentiation is required to make this strategy effective. Several studies have demonstrated that melatonin increases mature neuronal markers, which reflects NSC differentiation into neurons. Nevertheless, the possible involvement of mitochondria in the effects of melatonin during NSC differentiation has not yet been fully established. We therefore tested the impact of melatonin on NSC proliferation and differentiation in an attempt to determine whether these actions depend on modulating mitochondrial activity. We measured proliferation and differentiation markers, mitochondrial structural and functional parameters as well as oxidative stress indicators and also evaluated cell transplant engraftment. This enabled us to show that melatonin (25 μM) induces NSC differentiation into oligodendrocytes and neurons. These effects depend on increased mitochondrial mass/DNA/complexes, mitochondrial respiration, and membrane potential as well as ATP synthesis in NSCs. It is also interesting to note that melatonin prevented oxidative stress caused by high levels of mitochondrial activity. Finally, we found that melatonin enriches NSC engraftment in the ND mouse model following transplantation. We concluded that a combined therapy involving transplantation of NSCs pretreated with pharmacological doses of melatonin could efficiently restore neuronal cell populations in PD and AD mouse models depending on mitochondrial activity promotion.     

Regulation of hematopoietic stem cell aging in vivo by a distinct genetic element

Until recently, stem cells were thought to be endowed with unlimited self-renewal capacity and, thus, assumed exempt from aging. But accumulating evidence over the past decade compellingly argues that a measurable and progressive replicative impairment in the hematopoietic, intestinal, and muscle stem cell activity exists from adulthood to old age, resulting in a decline in stem cell function and rendering stem cell aging as the possible link between cellular aging and organismal aging. By using a previously uncharacterized congenic animal model to study genetic regulation of hematopoietic stem cell aging, we have demonstrated definitively that a locus on murine chromosome 2 regulates hematopoietic stem cell aging. In addition to demonstrating that hematopoietic stem cell aging is regulated by a distinct genetic element, experimental evidence links the response of hematopoietic stem cells to DNA double-strand breaks to cellular aging, suggesting DNA integrity influences stem cell aging.     

Regulation of the self-renewal probability in Hydra stem cell clones.

Hydra interstitial stem cells continuously give rise to daughter stem cells as well as precursors for nerve and nematocyte differentiation. Growth of the stem cell population is controlled by the self-renewal probability (Ps): Ps is the fraction of stem cell daughters that remain stem cells in each generation. We have determined Ps for Hydra interstitial stem cells by using a novel technique based on the cell conposition of clones. Stem cell clones were grown in aggregates of nitrogen mustard-inactivated Hydra tissue. They contain several hundred cells after 14 days of growth, including stem cells, differentiating nematocytes, and differentiating nerve cells. Clone size, size variability, and the ratio of differentiating cells to stem cells are sensitive measures of Ps. We have prepared standard curves relating these parameters to Ps, using computer simulations of clone growth. Comparisoon of the experimentally observed parameter of clones to these curves indicates that Ps decreases from 0.8 in 5- to 6-day clones to 0.6 in 10- to 12-day clones. The decrease in Ps coincides with the increase in clone size and suggest that Ps may be regulated by the density of stem cells in clones. Such a mechanism could be responsible for the observed homeostasis of stem cell populations in vivo.     

Human spleen cell generation of factors stimulating human pluripotent stem cell, erythroid, and myeloid progenitor cell growth

Mitogen-stimulated murine spleen cells produce humoral substances capable of supporting murine hematopoiesis and pluripotent stem cell proliferation in vitro. Thus, we evaluated conditioned media generated by human spleen cells (SCM) in the presence or absence of mitogens for factors stimulatory for human pluripotent (CFU-GEMM), erythroid (BFU- E), and myeloid (CFU-GM) precursors. Two and one half percent to 10% SCM stimulated proliferation of all three types of precursor cells from nonadherent buoyant human marrow target cells. Mitogen-stimulated SCM augmented CFU-GM (175% to 225%), whereas CFU-GEMM and BFU-E growth was essentially unchanged. Cell separation procedures used to determine which cells provided these microenvironmental stimuli indicated that nonadherent mononuclear spleen cells provided the bulk of the CSF-GM, whereas adherent cells (95% nonspecific esterase + monocyte- macrophages) and nonadherent cells provided similar proportions of CSF- mix and erythroid burst-promoting activity (BPA). The nonadherent cells generating high levels of CSF-mix, BPA, and CSF-GM were predominantly Leu-1-negative, ie, non-T, cells. In the presence or absence of mitogens, SCM was a more potent source (1.3- to 3.8-fold) than peripheral leukocyte CM of the growth factors for the three progenitor cell types. Specific in situ cytochemical stains for analyzing morphology of myeloid colonies demonstrated that SCM stimulated the proliferation of the same types and proportions of colonies as human placental CM, suggesting that these CMs may contain similar CSF-GMs. These data show the contribution of spleen cell subsets to the generation of hematopoietic growth factors and the responsiveness of these cells to various mitogenic stimuli.     

阿尔茨海默病的分子机制与神经干细胞治疗研究现状

阿尔茨海默病(AD)是以进行性记忆减退、认知障碍和人格改变为特征的脑退行性疾病,是导致老年前期和老年期痴呆的主要原因。AD主要病理学特征是在大脑皮层和海马区域形成大量的老年斑     

Regulation of airway stem cell proliferation in idiopathic pulmonary fibrosis

<正>Objective To investigate the effect of fibroblasts on regulating airway stem cell proliferation in idiopathic pulmonary fibrosis.Methods Lung cell suspension was prepared fromβ-actin-GFP mice.Airway stem cells were obtained by fluorescence activated cell sorting and co-