Evolutionary Conserved Mechanisms that Control Central Nervous System Development Regeneration and Degeneration

控制中枢神经系统发育、再生和退化的进化保守机制

• 批准号: 10705614
• 负责人: Ayelet Voskoboynik
• 金额: $ 38.77万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-30 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10705614
• 关键词: Adult; Affect; Age; Aging; Alzheimer' s Disease; Amyloid beta-Protein Precursor; Animals; Antisense RNA; Atlases; Behavioral; Biological Assay; Biological Metamorphosis; Biological Models; Brain; Candidate Disease Gene; Cell Aging; Cell Count; Cell Lineage; Cell Separation; Cell Transplantation; Cells; Central Nervous System; Chordata; Clinical Trials; Clonal Expansion; Clone Cells; Clustered Regularly Interspaced Short Palindromic Repeats; Collection; DNA; DNA Sequence Alteration; Dementia; Development; Disease; Early Onset Alzheimer Disease; Elements; Epigenetic Process; Exhibits; Failure; Frequencies; Gene Expression; Generations; Genes; Genetic Variation; Genome; Genotype; Homologous Gene; Human; Individual; Invertebrates; Larva; Life; Link; Longevity; Mediating; Molecular; Morphology; Mutation; Natural regeneration; Nerve Degeneration; Nervous System; Neurodegenerative Disorders; Neurons; Organ; Organism; Pathogenesis; Pathway interactions; Pattern; Phenotype; Population; Process; Publishing; Regenerative Medicine; Research; Role; Sampling; Secondary to; Senile dementia; Sexual Reproduction; Stimulus; Study models; Testing; Time; Tissues; Transplantation; Urochordata; Vertebrates; adult neurogenesis; age related; age related neurodegeneration; aged; aging brain; asexual; brain cell; circadian; circadian pacemaker; complement C2a; design; differential expression; fitness; germline stem cells; indexing; life history; model organism; nerve stem cell; nervous system development; neuron regeneration; preclinical trial; presenilin-1; progenitor; programs; prospective; reproductive; response; self organization; self renewing cell; self-renewal; sensory stimulus; single-cell RNA sequencing; stem cell aging; stem cell expansion; stem cell population; stem cell self renewal; stem cells; tissue regeneration; trait; transcriptome; transcriptomics

Gradual loss of brain function and neurodegeneration are common features of aging throughout diverse phyla. Senile dementias, including Alzheimer’s Disease (AD), likely involve failures of adult neural stem cell (NSC) number, viability, and/or functions. Our lab studies NSC’s role in central nervous system (CNS) development, adult regeneration, and in onset dementia such as AD. We are establishing a field of research in regenerative medicine and aging as the first lab to prospectively isolate human NSC and use them in published preclinical and clinical trial studies. In this proposal we seek to understand basic principles and evolutionarily conserved elements of NSC involvement in neuronal regeneration, degeneration, and aging in the colonial tunicate Botryllus schlosseri.  Botryllus has two reproductive modes: sexual reproduction which produces a primitive chordate with a simple CNS (the chordate brain), that will undergo metamorphosis into an asexually reproducing sessile invertebrate which propagates by budding. We have found that Botryllus buds contain self-renewing germline stem cells, and somatic stem cells which self-organize to form a colony composed of genetically identical individuals. This stage exhibits weekly assayable CNS tissue regeneration from candidate NSC and undergoes repeated neurodegeneration throughout its adult life, a process that resembles adult neurogenesis and neurodegeneration in vertebrates. Thus, Botryllus offers a unique opportunity to study the cellular and molecular mechanisms of CNS generation and degeneration through observing weekly regeneration cycles in young and old colonies (e.g. <3 months vs. >7 years). We aim to identify the mutations and/or epigenetic changes that accumulate in the NSC, and through self-renewal remain present throughout an organism's life. We have undertaken a systematic molecular (brain transcriptomic) analysis of CNS cells of old and young Botryllus colonies, paired with morphological and behavioral characterization of each of their CNS lineage cells. This analysis revealed 93 homologous genes that correlate with Alzheimer’s disease, including APP, GRN, PSEN1, GLUD2, and VPS35 that are differentially expressed between young and old colonies. Furthermore, the brains of old colonies contain a lower number of cells and have reduced neuron-mediated responses to sensory stimuli. Since stem cells are the only cells that self-renew and are maintained throughout the colony’s life, we hypothesize that genetic mutations or epigenetic changes that accumulate over time in NSC and their progenitors are the main cause of age-related neurodegenerative diseases. To test this hypothesis, we plan to characterize the molecular and cellular diversity of the Botryllus brain in chordate larvae and young and old colonies, isolate their NSCs at the single cell level, identify mutations that accumulate in NSC DNA, and test their effect on brain regeneration and function. Morpholino anti-sense RNAs will also be used to manipulate the activity of genes whose genetic variation predicts the onset of Alzheimer’s disease and test their effect on brain regeneration and degeneration capacity, and also attempt to introduce permanent alterations of their genomes by CRISPR.

大脑功能逐渐丧失和神经退行性变是老年痴呆症（包括阿尔茨海默氏病 (AD)）的常见特征，可能涉及成体神经干细胞 (NSC) 数量、活力和/或功能的丧失。我们正在建立再生医学和衰老研究领域，作为第一个前瞻性分离人类 NSC 并将其用于已发表的研究的实验室。在这项临床前和临床试验研究中，我们试图了解群居被囊动物 Botryllus schlosseri 中 NSC 参与神经元再生、变性和衰老的基本原理和进化保守元素：有性繁殖，产生原始脊索动物。具有简单的中枢神经系统（脊索动物脑），它会变态为无性繁殖的无脊椎动物，并通过出芽繁殖。发现 Botryllus 芽含有自我更新的种系干细胞和体干细胞，它们自我组织形成由基因相同的个体组成的群体，该阶段表现出候选 NSC 每周可检测的中枢神经系统组织再生，并在其整个成年过程中经历反复的神经变性，这一过程类似于脊椎动物的成年神经发生和神经变性，因此，Botryllus 提供了一个独特的机会，通过观察每周的再生周期来研究 CNS 生成和变性的细胞和分子机制。我们的目标是识别在 NSC 中积累的突变和/或表观遗传变化，并通过自我更新在生物体的整个生命中持续存在。对年老和年轻的灰霉病菌落的 CNS 细胞进行分子（脑转录组）分析，并结合每个 CNS 谱系细胞的形态和行为特征，该分析揭示了 93 个与阿尔茨海默病相关的同源基因，包括APP、GRN、PSEN1、GLUD2 和 VPS35 在年轻和年老群体中表达差异，此外，年老群体的大脑含有较少数量的细胞，并且由于干细胞是唯一的，神经元介导的对感觉刺激的反应减少。为了测试这一点，神经干细胞及其祖细胞中随着时间的推移积累的基因突变或表观遗传变化是与年龄相关的神经退行性疾病的主要原因。根据假设，我们计划表征脊索动物幼虫以及年轻和年老菌落中灰霉病大脑的分子和细胞多样性，在单细胞水平上分离它们的 NSC，识别 NSC DNA 中积累的突变，并测试它们对大脑再生和功能的影响吗啉代反义RNA还将用于操纵基因的活性，这些基因的遗传变异可预测阿尔茨海默病的发病，并测试它们对大脑再生和退化能力的影响，并尝试引入其基因的永久性改变。通过 CRISPR 基因组。