第三区段-16学时神经发育与干细胞2012级

1、干细胞与神经系统发育Haixia Lu MD, PhDProfessor of NeurobiologyInstitute of NeurobiologyE-mail: Tel: Xian Jiaotong University college of medicineIII-SNSXian Jiaotong University college of medicineIII-SNSReferences:其它：Advanced experimental medicine and biology chapter 2: Anteroposterior Regionalization of the B

2、rain: Genetic and Comparative AspectsNeuroscience - exploring the brain, Second editionWikipedia （维基百科）and Pubmed 1.吕国蔚 主编医学神经生物学，第2版，高等教育出版社2.寿天德 主编神经生物学，第2版，高等教育出版社3.朱晓峰 主编神经干细胞基础与应用，第1版，科学出版社4.李云庆 主编神经科学基础，第2版，高等教育出版社5.齐建国 主编神经科学扩展，第1版，人民卫生出版社前期有关“神经系统发育”的课程内容1. 人胚早期发育 人体生物学绪论区段2. 神经系统的胚胎发育 感觉器官与

3、中枢神经系统区段Morphological development of nervous systemCellular development of Nervous systemStem cell (SC) & Neural stem cell (NSC)Xian Jiaotong University college of medicineIII-SNSPart IPart IIPart IIINeural Dysplasia (神经发育异常) ？Neural Dysplasia (神经发育异常) 1. 与骨性结构发育异常相关（颅骨，脊柱） 神经管闭合缺陷：如颅骨裂、显性或隐性脊柱裂李云庆

4、主编神经科学基础，第2版，高等教育出版社Neural Dysplasia (神经发育异常) 颅骨和脊柱畸形： 如狭颅症、小头畸形、枕大孔区畸形、 寰枢椎脱位、寰椎枕化、颈椎融合、 小脑扁桃体下疝等Acrocephaly （尖头畸形）Scaphocephaly （舟状头畸形）Brachycephaly （园头畸形）Plagiocephaly （斜头畸形）园头畸形舟状头畸形小头畸形尖头畸形李云庆 主编神经科学基础，第2版，高等教育出版社1. 与骨性结构发育异常相关（颅骨，脊柱）Neural Dysplasia (神经发育异常) 1. 与骨性结构发育异常相关（颅骨，脊柱） 脑室发育畸形：如中脑导水管

5、闭锁、第四脑室正中孔以 以及外侧孔闭锁、CSF循环障碍导致先天性脑积水李云庆 主编神经科学基础，第2版，高等教育出版社Neural Dysplasia (神经发育异常) 2. 神经组织发育缺陷 头颅增大：如脑积水、脑积水性无脑畸形、巨脑畸形 脑皮质发育不全：如脑回增宽、脑回狭小、脑叶萎缩型硬化和 神经细胞异位 先天性脑穿通畸形（congenital porencephalia）：由于局部脑皮 质发育缺陷，脑室向表面开放如漏斗状，可双侧对称发生 无脑畸形：大脑完全缺如，颅盖和头皮缺失，生后不久死亡 胼胝体发育不全：胼胝体完全或部分缺失，常伴脑积水、小头畸形和 颅内先天性脂肪瘤等，临床可无症状或表

6、现癫痫或智能低下李云庆 主编神经科学基础，第2版，高等教育出版社脑穿通畸形李云庆 主编神经科学基础，第2版，高等教育出版社李云庆 主编神经科学基础，第2版，高等教育出版社Neural Dysplasia (神经发育异常) 3. 脑性瘫痪：表现为先天性运动功能异常4. 神经外胚层发育不全：神经皮肤综合症神经皮肤综合征所包括的疾病已知有20余种，临床上常见的有神经纤维瘤病、结节性硬化、脑一面血管瘤病；少见的有伊藤色素减少症、小脑视网膜血管瘤病等。均属于神经系统遗传性疾病。 李云庆 主编神经科学基础，第2版，高等教育出版社Xian Jiaotong University college of med

7、icineIII-SNSPart I寿天德 主编神经生物学，第2版，第8章Morphological development of nervous system吕国蔚 主编医学神经生物学，第2版，第9章（中枢）神经系统的形态发育 Ectoderm - neural tube - brain and spinal cord Establishment of neural axis: anterior-posterior and dorsal-ventral relation The common characteristics of neural development -from Hydra

8、to HumanNotochord(脊索)-mesodermThe entire nervous system arises from the ectodermHydra 水螅Zebrafish（斑马鱼）昆虫 insect Neurulation in vertebrates results in the formation of the neural tube, which gives rise to both the spinal cord and the brain. 脊椎动物的神经外胚层细胞形成神经管（最终形成大脑和脊髓）的过程，称为神经胚化Neurulation (神经胚化)*Par

9、t I神经系统的形态发育Neurulation包括三个阶段 2) the neural folds 神经褶 (day 20-21)Part I神经系统的形态发育 1) the neural plate 神经板 (day 18-19) 3) the neural tube 神经管 最终形成脑和脊髓 (day 22-26) Part I神经系统的形态发育 1) the neural plate 神经板 (day 18-19) The notochord（脊索） induces the formation of the central nervous system (CNS) by signalin

10、g the ectoderm germ layer（外胚层）above it to form the thick and flat neural plate. 来自中胚层的脊索刺激其上方的外胚层不断变厚，形成神经板 Part I神经系统的形态发育外胚层细胞不断增多，中间部位向下凹陷，形成一条沟，称之为神经沟，也称神经褶 2) the neural folds 神经褶 (day 20-21)Part I神经系统的形态发育3) the neural tube 神经管 最终形成脑和脊髓 (day 22-26) The neural plate folds in upon itself to form

11、 the neural tubes（神经管）, which will later differentiate into the spinal cord（脊髓） and the brain（脑）, eventually forming the central nervous system. Part I神经系统的形态发育神经嵴（neural crest）原始脑泡神经管背侧的细胞群与神经管分离，形成前后走行的细胞区带。最终形成PNS的感觉神经元、自主神经节节后神经元以及肌细胞、骨与软骨细胞、黑素细胞等Part I神经系统的形态发育初级神经胚化和次级神经胚化Different portions of

12、 the neural tube form by two different processes, called primary and secondary neurulation, in different species.不同物种，不同部位的神经管形成的过程不同1）Primary Neurulation初级神经胚化2）Secondary Neurulation 次级神经胚化The neural plate creases inward until the edges come in contact and fuse.neural foldneural tubePart I神经系统的形态发育

13、1）Primary Neurulation2）Secondary Neurulation Neural tube forms by hollowing out of the interior of a solid precursor.Secondary Neurulation occurs in the posterior section of most animals but it is better expressed in birds. Cranial neuropore anlage brain原基anlage spinal cordCaudal neuroporeCNSThe neu

14、ral tube formation神经孔体节Neural tubes from both primary and secondary neurulation eventually connect.Spina bifida (脊柱裂) ：the open ends of the neural tube fail to close 部位特点，功能影响 Ectoderm - neural tube - brain and spinal cord Establishment of neural axis: anterior-posterior and dorsal-ventral relationX

15、ian Jiaotong University college of medicineIII-SNSPart IMorphological development of nervous system神经系统的形态发育寿天德 主编神经生物学，第2版，第8 章吕国蔚 主编医学神经生物学，第2版，第9章神经系统的形态发育I. Anterior-posterior regionalization of brain（头-尾轴）-advanced experimental medicine and biology, chapter 2:Anteroposterior Regionalization of

16、the Brain: Genetic and Comparative Aspects 1) otd/Otx and ems/Emx genes - involve in specification of the anterior brain2) Hox genes - involve in the differentiation of the posterior brain3) Pax genes - involve in the development of the anterior/ posterior brain boundary zone 上述基因属同源盒基因（homeobox gen

17、e），是控制发育的主要基因，对动物的器官发生和细胞分化调控起关键作用。 Part Iotd/Otx and ems/Emx genesHox (homeotic) genesPax genesPax基因家族编码的蛋白是一组极为重要的转录调控因子,在胚胎发育的器官形成中扮演重要角色,其主要功能包括:调控细胞增殖、促进细胞自我更新、诱导前体细胞定向转移 Hox 基因在胚胎发育中的表达水平对于组织和器官的形成具有重要的调控作用。该类基因的突变，就会在胚胎发育过程中导致某一器官异位生长，即本来应该形成的正常结构被其他器官取代了。 同源盒基因（homeobox gene）之一，最早发现与果蝇的头部发育有

18、密切的关系Sonic hedgehog (Shh): is a key player in patterning the ventral axis 2) Bone morphogenic proteins (Bmp) and Wnt family members: play an important role in patterning the dorsal axis 3) Other factors: Fibroblast growth factors (FGF) and Retinoic Acid (RA) provide positional information to the neu

19、ral progenitor cellsXian Jiaotong University college of medicineIII-SNSII. Dorsal-ventral patterning of neural tube（背-腹轴）Part I神经系统的形态发育Shh secreted from the floor plate creates a gradient along the ventral neural tube. Shh functions in a concentration-dependent manner to specify ventral neuronal fa

20、tes. V0-V3 represent four different classes of ventral interneurons, and MN indicates motor neurons.Xian Jiaotong University college of medicineIII-SNS中间神经元V1,V2,V3底板细胞运动神经元Xian Jiaotong University college of medicineIII-SNSXian Jiaotong University college of medicineIII-SNSPart IICellular developme

21、nt of nervous system细胞神经发育细胞确定吕国蔚 医学神经生物学，第9章，第2节神经细胞的发育细胞增殖细胞迁移突触形成轴突延伸不完善，不准确Part IICellular development of nervous system细胞神经发育1. Development of neural progenitors 神经前体细胞的发育2. Neural progenitors differentiate into neuron and glia 神经前体细胞分化为神经元和胶质细胞3. Neural cell migration 神经细胞迁移4. Neuronal axons e

22、xtension 神经元轴突延伸5. Synapse formation 神经突触形成6. Neural network 神经网络形成OutlineXian Jiaotong University college of medicineIII-SNSPart II细胞神经发育1. Development of neural progenitors 神经前体细胞的发育-细胞增殖神经前体细胞 neural progenitorsNeural tube-MSCNeural-epitheliaMSC： multipotent stem cellneural tubeVentricular zoneMa

23、ntle layer Neuroblastneural tubePseudostratified epithelium(假复层上皮) Xian Jiaotong University college of medicineIII-SNSCell processes extension while cell body stay in ventricular zone (G1，细胞发出突起)During the synthesis of DNA, cell body migrate away from ventricular zone (S，细胞向表层移动) After the synthesis

24、, cell body move back to ventricular zone along its process(G2，细胞核返回)Cell process retract (突起缩回)Cell division（细胞分裂）Cell proliferation Xian Jiaotong University college of medicineIII-SNSNeural-epitheliaCell proliferation - a characteristic of the choreography of cell proliferationXian Jiaotong Univer

25、sity college of medicineIII-SNSCell divisionCell proliferation - The fate of the newly formed daughter cellsDaughter cells cleaved vertically from the precursor remain in the ventricular zone to divide again and again.This mode of cell division predominates early in development expand the population

26、 of neuronal precursorA = A + AXian Jiaotong University college of medicineIII-SNSCell proliferation - The fate of the newly formed daughter cellsDaughter cells cleaved horizontally from the precursor, one migrates away to take up its position in the cortex, where it will never divide again. The oth

27、er daughter remains in the ventricular zone to undergo more division.Ventricular zone precursor cells repeated this pattern until all of the neurons of the cortex have been generated. This mode predominates later in development neuronal precursorA = A + BXian Jiaotong University college of medicineI

28、II-SNSCell proliferation-How does the cleavage plane during cell division determine the cells fate?Xian Jiaotong University college of medicineIII-SNS -The distribution of cell constituents in precursor cells:植物极动物极the gene expression is regulated by its transcription factorsNotch-1 “unopposed” by n

29、umb, activates the gene expression that the cell to cease division and migrate away from the ventricular zone.Xian Jiaotong University college of medicineIII-SNSCell proliferation - How does the cleavage plane during cell division determine the cells fate? - The distribution of cell constituents in

30、precursor cells:Part II细胞神经发育2. Neural progenitors differentiate into neuron and glia 神经前体细胞分化为神经元和胶质细胞fate decisionNeuroblastsNeuronsGliaXian Jiaotong University college of medicineIII-SNSNeuronal differentiation 神经元分化 Differentiation of the neuroblast into a neuron begins with the appearance of ne

31、urites sprouting off the body (axon and dendrite at first). 开始于突起的形成NeuronsNeuroblasts The differentiation is programmed well before the neuroblast arrives at its final resting place. 边分化边迁移Xian Jiaotong University college of medicineIII-SNS神经细胞分化的影响因素Cell fate:geneExtracellular factorsnicheCell rec

32、eptors(Notch-numb, BMP, Wnt, Noggin)Different factors work on different level:CytokinesDNARNAsiRNAShort distance: cell-cell influence through Notch and Delta Long distance: follistatin, noggin, chordin and BMP Hans Spmann and Hilde MangoldOrganiser 组织者 Xian Jiaotong University college of medicineIII

33、-SNS Long distanceHans Spmann and Hilde MangoldP144右图Xian Jiaotong University college of medicineIII-SNSOrganiser 组织者 Long distanceNeural progenitor in the center（Dark Green）inhibits the surrounding neuroectodermal cells (Light Green) to have vertical cleavage，consequently differentiated into epider

34、mal cells (White). Cell differentiationXian Jiaotong University college of medicineIII-SNS Short distanceNotch and Delta Progenitor with high level Delta and low level Notch expression（Green）stop its neighbor cells expressing AS-C and Delta genesXian Jiaotong University college of medicineIII-SNSCel

35、l differentiation Short distanceNotch and Delta Notch plays important role in differentiation of progenitors Normal Notch- Notch+ Xian Jiaotong University college of medicineIII-SNSCell differentiation Short distanceNotch and Delta neural tubeVentricular zoneMantle layerNeuroblastneural tubeCell mig

36、rate away from ventricular zone（VZ）Xian Jiaotong University college of medicineIII-SNSPart II神经细胞发育3. Neural cell migration 神经细胞迁移 - Inside-out development of the cortex - The first group of cells migrate to cortical plate(皮质板), from VZ that form subplate (板下区) Xian Jiaotong University college of me

37、dicineIII-SNS3. Neural cell migration 神经细胞迁移较早分化的较大神经元先迁移并形成最内层，依次顺序向外；而较晚分化的较小神经元则通过已形成的层次迁移并形成其外侧新的层次；故不论皮质的什么区域，其最内层总是最早分化，而最外层则最后分化。Cell migrationAdultMLEGLEPLIGLIPLMFLXian Jiaotong University college of medicineIII-SNSThis shows neuroblasts climbing along the thin processes of the radial glia r

38、oute to the cortical plate, which forms just under the marginal zoneCell migrationHowever in cerebellum, granular cell migration is differentEGLMLPLIGLNeuoblasts in EGL will migrate back and form IGL after birthMLIGLXian Jiaotong University college of medicineIII-SNSCell migrationPart II细胞神经发育4. Neu

39、ronal axons extension 神经元轴突延伸4). Chemoattraction and chemorepulsion （向化性效应）1). Growing axon （轴突生长）2). Fasciculation （簇生，自发性收缩）3). Axon guidance and guidance cues （轴突延伸引导）1). Growing axon （轴突生长）The growing tip of a neurite is called a growth cone （生长锥）, which is specialized to identify an appropriate

40、 path for neurite elongation.Growth cone in culture- probe the environment, moving in and out of the lamellipodia- takes hold of the substrate and pull the advancing GC forward 丝足板足Xian Jiaotong University college of medicineIII-SNSCell adhesion molecules (CAMs)“highway” 2). Fasciculation （簇生，自发性收缩）

41、粘附分子的一种Xian Jiaotong University college of medicineIII-SNS3). Axon guidance and guidance cues （轴突延伸引导）Target cellExtracecular molecularsSpecial bindingSecond messengerFunction changes of microbubules and actin within growth coneControlling growth cone extendingGuidance cues: chemoattraction and acti

42、ns concentrate in forepart of a GC chemorepulsion and actins disappear in forepart of a GCMembrane receptorsXian Jiaotong University college of medicineIII-SNS4). Chemoattraction and chemorepulsion （向化性效应） Netrin spurs the axon growth toward the midlineThe receptors of Netrin and Slit are be regulat

43、ed in varying from one side of the midline to other pull Slit chase the axon away the midlinePushXian Jiaotong University college of medicineIII-SNSModel (chemical synapse ) Definition of synapse Classify of synapse Structure of synapse Synapse formation *Xian Jiaotong University college of medicine

44、III-SNSPart II细胞神经发育5. Synapse formation （神经）突触形成1) Definition of synapseIn the nervous system, a synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell 突触： 神经系统中允许神经元传递电信号或化学信号给其它细胞的特殊结构；神经元之间以及与其它细胞间的特化的细胞连接Synapses are essential to neuronal function:

45、 neurons are cells that are specialized to pass signals to individual target cells, and synapses are the means by which they do so. In many synapses, the presynaptic part is located on an axon, but some presynaptic sites are located on a dendrite or soma. Xian Jiaotong University college of medicine

46、III-SNSSynapse formation 神经突触形成 2) Classify of synapseThere are two fundamentally different types of synapsechemical synapseelectrical synapseXian Jiaotong University college of medicineIII-SNSSynapse formation 神经突触形成 In a chemical synapse, the presynaptic neuron releases a chemical called a neurotr

47、ansmitter that binds to receptors located in the postsynaptic cell, usually embedded in the plasma membrane. In an electrical synapse, the presynaptic and postsynaptic cell membranes are connected by channels that are capable of passing electrical current, causing voltage changes in the presynaptic

48、cell to induce voltage changes in the postsynaptic cellChemical synapseElectrical synapseXian Jiaotong University college of medicineIII-SNS3) Structure of synapseXian Jiaotong University college of medicineIII-SNSSynapse formation 神经突触形成 Structure of synapseSynaptic vesicleNeurotransmitterVoltage g

49、ated ion channelReuptake pumpPostsynaptic densityReceptorAxon terminalDendriteSynaptic cleftStructureEM:Xian Jiaotong University college of medicineIII-SNS4) Synapse formation *(1) Genesis of connection (突触形成-细胞间联系的建立) (2) Elimination of cell and synapse (细胞和突触数量减少) (3) Activity-dependent synaptic r

50、earrangement (活动依赖性突触重排) (4) Synapse plasticity (突触可塑性)与儿童发育过程中极其相似Xian Jiaotong University college of medicineIII-SNS 生长锥与适宜的细胞接触； 神经递质释放增加； 突触前膜与靶细胞粘附增强； 其它竞争突触被异突触压抑； 受体在突触后膜堆积； 新受体在突触后膜合成并插入； 接头外受体消除Synapse formation 神经突触形成 (1) Genesis of connection 突触形成-细胞间联系的建立The 3 phases of Synapse formation

51、 Pathway selection path When the growth cone comes in contact with its target, a synapse is formed.Which cell should link with?Target selection structureAddress selection cellWhere the axon should go?Axon extensionTarget cellExtracecular molecularsSpecial bindingMembrane receptorsXian Jiaotong Unive

52、rsity college of medicineIII-SNSThese three phases depend on :Direct cell-to-cell contact contact between cells and extracellular secretions of other cellcommunication via action potentials and synaptic transmission The 3 phases of Synapse formation Pathway selection pathTarget selection structureAd

53、dress selection cellTarget cellExtracecular molecularsSpecial bindingMembrane receptorsXian Jiaotong University college of medicineIII-SNS(1) Genesis of connection 突触形成-细胞间联系的建立 When the growth cone comes in contact with its target, a synapse is formed. The details of mechanisms of synapse formation

54、 in the CNS are still not clear yet - Most of the data comes from studies of the neuromuscular junction 1. The GMN terminal secretes agrin, (Ca+ entry into the GC triggers neuro- transmitter release and changes in the cytoskeleton adhere to its post- synapse partner) 2. Agrin interacts with MuSK in

55、the muscular cell membrane. 3. The clustering of Ach receptors in the postsynaptic membrane via the action of rapsyn (like a shepherd to gather the receptors at the synapse)Ca+Neuromuscular junction.Xian Jiaotong University college of medicineIII-SNSA process known as Programmed cell death (PCD). Ma

56、tching inputs with targets by selective cell death.The input neurons (突触前) will compete with one another for limited quantities of trophic factors produced by the target neurons.Cell death (2) Elimination of cell and synapse 细胞和突触数量减少Xian Jiaotong University college of medicineIII-SNSEach neuron (突触

57、后) can receive on its dendrites and soma a finite number of synapses called synaptic capacity （突触容量） A useful model system for the study of synaptic elimination: effect of postsynaptic AChR, basal membrane of muscular fibril on neuromuscular synaptic elimination.Changes in synaptic capacity哺乳动物出生后开始

58、进行精细动作的产生Xian Jiaotong University college of medicineIII-SNS(2) Elimination of cell and synapse 细胞和突触数量减少(3) Activity-dependent synaptic rearrangement 活动依赖性突触重排Synaptic segregation（突触分离）Xian Jiaotong University college of medicineIII-SNSThroughout the developing nervous system, competition between a

59、xons causes the permanent removal of some synaptic connections -Wen-Biao Gan and Jeff W. Lichtman. Synaptic Segregation at the Developing Neuromuscular Junction. Science, 1998: 282( 5393). 1508-1511 Synaptic segregation（突触分离）The two input neurons in one eye (top) fire at the same time. This is suffi

60、cient to cause the top LGN target neuron to fire but not the bottom one. This is the same situation that the two input neurons in the other eye (bottom) are active simultaneously, causing the bottom target neuron to fire.Over time, neurons that fire together wire together. Notice also that input cel