1、基底神经节疾病基底神经节疾病Outline1.Introduction of basal ganglia Overview and function, structure, and connections2.Disorders of basal ganglia Parkinsons disease Huntingtons disease (symptomatology, pathology, pothogenesis, treatment)1.Introduction of basal gangliaOverview and functionStructureConnections The b
2、asal ganglia are a group of nuclei in the brain interconnected with the cerebral cortex, thalamus and brainstem. Functions: motor control, cognition, emotions, and learning. 锥体系统锥体系统internal globus pallidus (GPi)external globus pallidus (GPe) ConnectionsCircuit of Basal GangliaDirect pathwayIndirect
3、 pathwayNigrostriatal pathwayGlutamateGABA Dopamine Direct: Motor cortex Putamen GPi Thalamus Motor cortex Indirect: Motor cortex Putamen GPe Subthalamic nucleus GPi Thalamus Motor cortex Nigrostriatal pathway: Pars compacta StriatumGluGABAGABAGluGluGABAGABAGluGABAGlu2. Disorders of Basal Ganglia Di
4、minished movement: Parkinsons disease Excessive movement: Huntington disease Neuropsychiatric cognitive and behavioral disturbancesParkinsons disease，PDAn Essay on the Shaking Palsy English physician James Parkinson (1817) IntroductionPD is the most common neurodegenerative disorder after Alzheimers
5、 disease.The prevalence is 0.3 in the whole population in industrialized countries, rising to 1% in those over 60 years of age and to 4% of the population over 80. Mean age of onset is around 60 years, although 5-10% of cases are considered of young onset ( the age of 20 and 50). The incidence is be
6、tween 8 and 18 per 100.000 person-years. EpidemiologyMonograph by James Parkinson1817SymptomatologyMovement disorders: resting tremor muscle rigiditybradykinesia and postural instability ParkinsonismCognitive and neurobehavioral problems(dementia)Sensory and sleep difficulties chronic and progressiv
7、eThe relationship of the basal ganglia to the major components of the motor system. Origins and terminations of (a) the corticospinal tract and (b) the rubrospinal tract.正常年青人，黑质细胞数为42.5万正常80岁老人，黑质细胞数减少到20.0万PD病人黑质细胞数减少到少于10 .0万Lewy bodyPathologyEtiologyPathogenesisCircuit disorder of Basal GangliaG
8、eneticDopamine oxidative stressToxinsOthersCircuit disorder of Basal Ganglia inhibition of the direct pathway excitation of the indirect pathway多巴胺神经元为何会发生黑质部选择性的退行性变呢？多巴胺神经元为何会发生黑质部选择性的退行性变呢？氧化应激损伤氧化应激损伤1、外源性毒物的侵入2、神经黑色素的存在3、DA的氧化应激代谢4、清除自由基的能力不全图31-5 多巴胺在神经元中的酶代谢及其代谢产物引自金国章,脑内多巴胺的生物医学1998年 OHOH CH
9、2NH2CH2OOCH2CH2NH2OH CH2NH2CH2O-Fe2+Fe3+O2O2Fe2+Fe3+O2O2H2O2多巴胺半醌多巴胺半醌多巴胺醌多巴胺醌DAO2MAODOPACH2O2HVACOMT Dopamine oxidative stressDopamine oxidative stressToxinsRotenone (an insecticide)MPTP 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine（1-甲基- 4-苯基- 1, 2, 3, 6-四氢吡啶）Paraquat (a herbicide) 6-Hydroxydopamin
10、e ( 6-OHDA) Heavy metals RotenoneMPTPParaquat6-Hydroxydopamine, or 6-OHDA The neurotoxins used in animal models of PD induce mitochondrial dysfunction. 一种理想的动物模型应该符合下列5种标准：1. 出生时，应有正常而完整的DA neurons，并在成年期开始逐渐退化丧失且超过50%。2. 具有容易检测的运动功能障碍。3. Lewy bodies的形成。4. 如模式是genetic，应以单一点突变为基础。5. 较短的时程，约数月。Geneticm
11、itochondrial dysfunction, oxidative damage, abnormal protein accumulation and protein phosphorylation 1.Synuclein (SNCA)/PARK1seen mainly in presynaptic terminals include , and -synuclein play a role in synaptic vesicle recycling, storage and compartmentalization of neurotransmitters and associates
12、with vesicular and membranous structuresSer129的磷酸化 -synuclein基因的倍增 Overview of the a-syn aggregation process integrated with the oxidative stress pathway and the UPP. Parkin functions as an E3 ubiquitin protein ligase by targeting misfolded proteins to the ubiquitn proteasome pathway for degradation
13、, and the loss of its E3 ligase activity due to mutations lead to autosomal recessive early-onset PD. 2.Parkin/PARK2ubiquitin proteasome system，UPS 3.PINK1(PTEN-induced putative kinase 1)/PARK6serinethreonine kinase (mitochondria)a pivotal regulator of mitochondrial quality4.UCH-L1/PARK5utative kina
14、se 1 (PINK1)Ubiquitin carboxyl-terminal hydrolase L1neuron-specific protein PGP 9.5one of the most abundant proteins in the brain (2%)hydrolytic activity, ligase activity and binding mono-ubPossible role of UCH-L1 in PD. Mechanisms of neurotoxicant-induced proteasome dysfunction and dopaminergic deg
15、eneration. Transgenic animal model alpha-synuclein A30P+A53T, LRRK2(R1441G), parkin, R621C synphilin-1 mouse, C. elegans , Drosophila, zebrafish InflammationNeuroinflammation is mediated predominately by microglia, the resident immuno-competent and phagocytic cells within the CNS.Microglia, represen
16、ting 520% of brain cellsMicroglial cell density in the SN is 45 times higher than in other regionsActivated cells also produce pro-inflammatory molecules Schematic representation of lipopolysaccharide(LPS)-induced and glial activation-mediated dopamine (DA) neurodegeneration.Key molecular mechanisms
17、 that are widely accepted to contribute to the neurodegenerative process in dopaminergic neurons in the substantia nigra in Parkinson disease. At least two of the three major symptoms are present.Possible causes for symptoms Response to levodopa The main tools used to make a diagnosis: Neurological
18、examination Motor physiology tests Neuro-imaging: PET(18-flurodopa ),CT, MRI Lewy bodies during autopsy (gold standard) DiagnosisTreatment There is no known cure for Parkinsons disease. Treatment is aimed at controlling the symptoms. Medications control symptoms primarily by controlling the imbalanc
19、e between the transmitters.Therapeutic strategyDirectly improve the function of dopamine neurotransmission Indirectly improve the function of dopamineSurgery and deep brain stimulationdopamine in the brain Precursor Rate-limiting step , decrease in PDL-dopaPeripheral inhibitorsThe central and periph
20、eral metabolism of levodopa and its modification by drugs.easily pass through the blood-brain barrieris transformed into dopamine in the dopaminergic neurons by DDCis often metabolised to DA elsewhere, causing a wide variety of side effects COMT inhibitors , MAO-B inhibitorsL-dopaLong-term effects o
21、f L-DOPA： On/off oscillations Dose failure (drug resistance)Dopamine dysregulation syndromeAch: movementAch increases inhibition o GABAdenosine: movementAdenosine increase the effects of Ach on the GABAergic neurons;Adenosine counter D2 receptor activity;Adenosine reduces GABA release.Enkephalin Dyn
22、orphinPeptide modulation of striatal input to the globus pollidus.Pallidotomy and Subthalamotomy Surgery is used in people with advanced PD for whom drug therapy is no longer sufficient.Because these procedures cause permanent destruction of brain tissue, they have largely been replaced by deep brai
23、n stimulation (DBS) for treatment of Parkinsons disease.DBS is primarily used to stimulate one of three brain regions: the subthalamic nucleus, the globus pallidus, or the thalamus.Research directions Animal models Gene therapy (virus )Neuroprotective treatments (GDNF)Neural transplantation Stem cel
24、ls transplants have raised great recent interest. When transplanted into the brains of rodents and monkeys they survive and improve behavioral abnormalities. Nevertheless while fetal stem cells are the easiest to manipulate their use is controversial. Such controversy may be overcome with the use of
25、 induced pluripotent stem cells from adults. A scheme of the generation of induced pluripotent stem (iPS) cells. (1)Isolate and culture donor cells. (2)Transfect stem cell-associated genes into the cells by viral vectors. Red cells indicate the cells expressing the exogenous genes. (3)Harvest and cu
26、lture the cells according to ES cell culture, using mitotically inactivated feeder cells (lightgray). (4)A small subset of the transfected cells become iPS cells and generate ES-like colonies. 主要讲解的内容主要讲解的内容: :1 基底神经节的脑内组成的核团、它们的分布、主要通路的组成 及其参与调节每条通路中的神经递质及其功能。2 基底神经节（黑质）损伤后的主要临床表现及其病理表现的关系。3 PD脑内黑质
27、多巴胺神经元退化的机制研究。4 Parkinsons Disease (PD)的治疗方案及治疗基础。思考题：1What are the components of the basal ganglia?2How are the structures of the basal ganglia connected?3Describe the corticostriatal projections.4Describe the connections between subthalamus and globus pallidus.5Describe the importance of the nigra
28、strital pathways.6What is the role of the basal ganglia in relation to the motor thalamus?7What are the principal neurotransmitters and receptors associated with the basal ganglia?8A disorder of the basal ganglia is indicated what signs?9Can administration of dopamine cure Parkinsons disease? Why?10
29、. Describe the etiology of neurodegeneration in the substantia nigra in PD.11. Why dose lesioning the SThn or GP reduce the symptoms of PD? Huntingtons disease (HD)In 1872 George Huntington thoroughly described the disorder in his first paper On Chorea .IntroductionThe worldwide prevalence of HD is
30、5-10 cases per 100,000 persons. It usually appears in middle age (30-50 years)EpidemiologyHD/chorea is an inherited （ autosomal dominant inheritance ）progressive neurodegenerative disorder, which affects muscle coordination and leads to cognitive decline and dementia. It typically becomes noticeable
31、 in middle age.abnormalities in peripheral tissues ( muscle atrophy, cardiac failure, impaired glucose tolerance)SymptomatologyProminent cell loss and atrophy in striatum.astrocytesPathologynuclear and cytoplasmic inclusionsPathogenesisPathogenesisHtt is expressed in all mammalian cells. ( brain) in
32、teracts with over 100 other proteins, and appears to have multiple biological functions.embryonic development, anti-apoptosis, controling the production of BDNF, facilitating vesicular transport and synaptic transmission, and controling neuronal gene transcription.Pathogenesis1.Loss of Htt function
33、2. Toxic function of mHttGlutamateGABA Dopamine Diagnosis typical symptoms a family history of the disease genetic testing to have the expanded trinucleotide repeatphysical examination , psychological examination , Medical imaging There is no known cure for HD. Treatment is aimed at controlling the
34、symptoms.tetrabenazine (chorea)antipsychotic drugs TreatmentPrognosis The length of the trinucleotide repeat accounts for 60% of the variation in the age of onset and the rate of progression of symptoms. A longer repeat results in an earlier age of onset and a faster progression of symptoms. Life ex
35、pectancy in HD is generally around 20years following the onset of visible symptoms. Research directions Appropriate animal models (transgenic animals )Genetically engineered intrabodies (an inhibition of mHtt aggregation) have been shown to prevent mortality during the development stages of Drosophila models. Gene silencing (mHtt is reduced )Stem cell therapy Numerous drugs Thank you！
