Regenerative neurogenesis in adult zebrafish brain after neurodegeneration
Ontology highlight
ABSTRACT:
ORGANISM(S): Danio rerio
PROVIDER: GSE268721 | GEO | 2026/07/02
REPOSITORIES: GEO
Similar Datasets
Project description:The decline of cognitive function is a feature of normal human aging and is exacerbated in AlzheimerM-bM-^@M-^Ys disease (AD). DNA repair declines in brain cells during normal aging and even more so in AD. Here we show that experimental reduction in levels of the base excision repair enzyme, DNA polymerase M-NM-2 (Polb) renders neurons vulnerable to age-related dysfunction and degeneration in a mouse model of AD. Whereas 3xTgAD mice exhibit age-related extracellular amyloid b-peptide (Ab) accumulation and cognitive deficits, but no neuronal death, 3xTg/Polb+/- mice accumulates intracellular Ab and neurons die in the hippocampus and cerebral cortex. The DNA repair-deficient 3xTgAD mice exhibited increased DNA strand breaks and apoptotic caspase activation with loss of hippocampal volume, and impaired synaptic plasticity and memory retention. Molecular profiling revealed remarkable similarities in gene expression alterations in brain cells of AD patients and 3xTgAD/Polb+/- mice including multiple abnormalities suggestive of impaired cellular bioenergetics. Our findings demonstrate that a modest decrement in oxidative DNA damage processing is sufficient to render neurons vulnerable to AD-related pathogenic molecular and cellular alterations that result in the dysfunction and death of neurons, and associated cognitive deficits. 4 mouse strains were used in these experiments, the 3xTgAD and Pol M-NM-2 (+/-) mice were bred at the National Institute on Aging (Baltimore, Maryland). The original line 3xTgAD line was generated as described previously (Oddo, et. al 2003) and possess APPswe, PS1M146V, and tauP301L mutations. DNA polymerase beta heterozygous mice, Pol M-NM-2 (+/-), were crossed with the 3xTgAD mice to generate a 3xTgAD/Pol M-NM-2 (+/-) mouse. The Wt strain is C57Bl/6. At 20 months of age these mice were euthanized by cervical dislocation, the brain removed from the skull and dissected into regions of interest, the prefrontal cortex was used for the microarray studies.
2015-01-05 | E-GEOD-60911 | biostudies-arrayexpress
Project description:The decline of cognitive function is a feature of normal human aging and is exacerbated in Alzheimer’s disease (AD). DNA repair declines in brain cells during normal aging and even more so in AD. Here we show that experimental reduction in levels of the base excision repair enzyme, DNA polymerase β (Polb) renders neurons vulnerable to age-related dysfunction and degeneration in a mouse model of AD. Whereas 3xTgAD mice exhibit age-related extracellular amyloid b-peptide (Ab) accumulation and cognitive deficits, but no neuronal death, 3xTg/Polb+/- mice accumulates intracellular Ab and neurons die in the hippocampus and cerebral cortex. The DNA repair-deficient 3xTgAD mice exhibited increased DNA strand breaks and apoptotic caspase activation with loss of hippocampal volume, and impaired synaptic plasticity and memory retention. Molecular profiling revealed remarkable similarities in gene expression alterations in brain cells of AD patients and 3xTgAD/Polb+/- mice including multiple abnormalities suggestive of impaired cellular bioenergetics. Our findings demonstrate that a modest decrement in oxidative DNA damage processing is sufficient to render neurons vulnerable to AD-related pathogenic molecular and cellular alterations that result in the dysfunction and death of neurons, and associated cognitive deficits.
2015-01-05 | GSE60911 | GEO
Project description:Alzheimer's disease (AD) is a devastating neurodegenerative disorder characterized by a progressive cognitive decline. Epidemiological studies have suggested a protective role of caffeine consumption against age-related cognitive impairments and the risk of developing AD. Effects of caffeine have been particularly ascribed to its ability to block adenosine A2A receptors (A2ARs). Early pathological upregulation of these receptors by neurons is thought to be involved in the development of synaptic and memory deficits in AD but this remains ill-defined. To tackle this question, we employed a novel transgenic mouse model allowing to promote a neuronal upregulation of A2AR in the hippocampus of APP/PS1 mice, developing AD-like amyloidogenesis. This new model was used to determine the impact of an early upregulation of A2AR on the progression of neuropathological lesions, associated behavior and underlying mechanisms in APP/PS1 mice. Our findings revealed that the early upregulation of A2AR in the presence of an ongoing amyloid pathology exacerbates memory impairments of APP/PS1 mice. These behavioral changes were not linked to major change in the development of amyloid pathology but rather associate with an increased p-tau at neuritic plaques. Moreover, proteomic and transcriptomic analysis coupled to quantitative immunofluorescence studies indicated that neuronal impairment of the receptor promoted both neuronal- and non-neuronal autonomous alterations i.e. loss of excitatory synapses and neuroinflammatory response, respectively, both presumably accounting for the detrimental effect on memory. Overall, our results provide compelling evidence that neuronal A2AR dysfunction as seen in the brain of patients contributes to AD pathogenesis, favoring synaptic deficits promoted by both amyloid (this study) and tau lesions (our previous study). In addition to provide new insights into the complex pathophysiology of AD, the present findings underscore the potential of A2AR as a relevant therapeutic target for mitigating early synaptic loss in this neurodegenerative disorder.
2023-11-30 | GSE248245 | GEO
Project description:Genetic variants in ABCA7, an Alzheimer's disease (AD)-associated gene, elevate AD risk, yet its functional relevance to the etiology is unclear. We generated a CRISPR-Cas9-mediated abca7 knockout zebrafish to explore ABCA7's role in AD. Single-cell transcriptomics in heterozygous abca7+/- knockout combined with Aβ42 toxicity revealed that ABCA7 is crucial for neuropeptide Y (NPY), brain-derived neurotrophic factor (BDNF), and nerve growth factor receptor (NGFR) expressions, which are crucial for synaptic integrity, astroglial proliferation, and microglial prevalence. Impaired NPY induction decreased BDNF and synaptic density, which are rescuable with ectopic NPY. In induced pluripotent stem cell-derived human neurons exposed to Aβ42, ABCA7-/- suppresses NPY. Clinical data showed reduced NPY in AD correlated with elevated Braak stages, genetic variants in NPY associated with AD, and epigenetic changes in NPY, NGFR, and BDNF promoters linked to ABCA7 variants. Therefore, ABCA7-dependent NPY signaling via BDNF-NGFR maintains synaptic integrity, implicating its impairment in increased AD risk through reduced brain resilience.
2024-07-19 | GSE244550 | GEO
Project description:Neural stem cells (NSCs) constitute the reservoir for new cells and might be harnessed for stem cell-based regenerative therapies. Zebrafish has remarkable ability to regenerate its brain by inducing NSC plasticity upon Alzheimer’s pathology. We recently identified that NSCs enhance their proliferation and neurogenic outcome in an Amyloid-beta42-based (Aβ42) experimental Alzheimer’s disease model in zebrafish brain and Interleukin-4 (IL4) is a critical molecule for inducing NSC proliferation in AD conditions. However, the mechanisms by which Aβ42 and IL4 affect NSCs remained unknown. Using single cell transcriptomics, we determined distinct subtypes of NSCs and neurons in adult zebrafish brain, identified differentially expressed genes after Aβ42 and IL4 treatments, analyzed the gene ontology and pathways that are affected by Aβ42 and IL4, and investigated how cell-cell communication is altered through secreted molecules and their receptors. Our results constitute the most extensive resource in the Alzheimer’s disease model of adult zebrafish brain, are likely to provide unique insights into how Aβ42/IL4 affects NSC plasticity and yield in novel drug targets for mobilizing neural stem cells for endogenous neuro-regeneration.
2020-04-01 | GSE118599 | GEO
Project description:The neural stem cell (NSC) reservoir can be harnessed for stem cell-based regenerative therapies. Zebrafish remarkably regenerate their brain by inducing NSC plasticity in a Amyloid-β-42 (Aβ42)-induced experimental Alzheimer’s disease (AD) model. Interleukin-4 (IL-4) is also critical for AD-induced NSC proliferation. However, the mechanisms of this response have remained unknown. Using single-cell transcriptomics in the adult zebrafish brain, we identify distinct subtypes of NSCs and neurons and differentially regulated pathways and their gene ontologies and investigate how cell-cell communication is altered through ligand-receptor pairs in AD conditions. Our results propose the existence of heterogeneous and spatially organized stem cell populations that react distinctly to amyloid toxicity. This resource article provides an extensive database for the molecular basis of NSC plasticity in the AD model of the adult zebrafish brain. Further analyses of stem cell heterogeneity and neuro-regenerative ability at single-cell resolution could yield drug targets for mobilizing NSCs for endogenous neuro-regeneration in humans.
2019-12-04 | GSE118577 | GEO
Project description:Alzheimer’s disease (AD) is hallmarked by progressive neurodegeneration. Aggregation of amyloid-β peptides (Aβ) is thought to play a pivotal role in driving AD pathogenesis, yet the underlying mechanisms remain unclear. Here, we use yeast genome-scale screening to study global synthetic genetic interactions and identify toxicity modifiers of Aβ42. We find that the gene encoding riboflavin kinase (FMN1) and its metabolic product flavin mononucleotide (FMN) are connected to AD. These relationship between Aβ42 and FMN was previously unknown. As a cofactor for flavoenzymes, FMN supplementation appears to attune many cellular processes to ameliorate Aβ42 toxicity. RNA-seq analysis further confirms FMN’s cytoprotective mechanisms. Our findings provide increased understanding of FMN regulated cellular pathways which are associated with potential targets for AD treatment.
2020-02-27 | GSE128905 | GEO
Project description:Epidemiological studies suggest that consumption of caffeine, the most commonly consumed psychoactive substances found in coffee, tea or soft drinks reduces the risk of developing Alzheimer’s disease (AD). While previous studies employing transgenic AD mouse models reported on reduced amyloid plaque load or an amelioration of behavioral deficits, there is only limited information on its potential effects on neurodegeneration. In the current study, we assessed whether long-term caffeine consumption affects hippocampal neuron loss and associated behavioral deficits in the Tg4-42 mouse model of AD. Treatment over a 4 months period reduced hippocampal neuron loss, rescued learning and memory deficits and ameliorates impaired neurogenesis. Neuron-specific hippocampal transcriptome analysis revealed an altered expression profile with an up-regulation of genes linked to synaptic function and processes, as well as neural progenitor proliferation. Treatment of 5xFAD mice with the same paradigm also rescued behavioral deficits, however, without affecting extracellular amyloid-beta (Abeta) levels or altered APP processing.
2021-12-13 | GSE183323 | GEO
Project description:The prevailing view frames microglia and macrophages as guardians against amyloid beta (Aβ) accumulation in Alzheimer’s disease (AD). Here, we overturn this paradigm by demonstrating that human phagocytic cells—including differentiated THP-1 macrophages and iPSC-derived microglia—are not merely passive responders but active producers of extracellular, seeding-competent Aβ42 fibrils, the amyloid species most strongly linked to parenchymal plaque formation and neurodegeneration. These cell-generated aggregates differ structurally and functionally from synthetic fibrils, exhibiting heightened seeding activity and the ability to cross-seed tau aggregation, a key driver of AD progression. Notably, Aβ42 fibril formation in this system requires active cellular processes and is exacerbated by loss of TREM2, a major AD risk gene. Transcriptomic profiling reveals an early inflammatory response resembling microglial states observed in human AD models, positioning this system as a tractable, human-relevant platform to dissect the interplay between Aβ aggregation, innate immunity, and genetic susceptibility. Our findings suggest that macrophages and microglia play a dual role in AD, acting both as responders and inadvertent catalysts of pathogenic amyloid formation, with implications for early therapeutic intervention.
2026-02-13 | GSE319445 | GEO
Project description:The repeated failures in developing disease-modifying therapies for Alzheimer's disease (AD) by targeting extracellular Aβ have urged a complete reassessment of the cellular mechanisms underlying Aβ neurotoxicity. Emerging evidence suggests that intraneuronal Aβ accumulation represents an early pathogenic event in AD, preceding extracellular plaque formation and neuroinflammatory responses. However, whether targeting intracellular Aβ can halt disease progression and how this can be achieved remain unknown. While investigating the brain transcriptional responses to Aβ pathology, we identified a neuroprotective role for the serine protease Yip7 in a Drosophila AD model. Neuronal overexpression of yip7 alleviated multiple Aβ42- induced deficits, including declines in locomotor activity, impaired proteostasis, increased brain ageing and neuronal death, and reduced lifespan. Unlike canonical digestive proteases, Yip7 is not secreted but instead localizes to the endosomal/lysosomal compartments via a putative transmembrane domain initially predicted as a signal peptide. Crucially, Yip7’s neuroprotective function depends on its proper subcellular localization rather than the catalytic triad of serine proteases. Mechanistically, rather than directly eliminating Aβ, Yip7 increased neuronal retention of Aβ, supporting a model in which Yip7 reduces Aβ42 toxicity by limiting its degradation/secretion. Notably, yip7 overexpression also conferred protection in a Huntington's disease model, underscoring its broader relevance. Together, these findings introduce a novel concept that intracellular Aβ sequestration by a serine protease can mitigate neurotoxicity, and propose targeting intracellular amyloid as a promising therapeutic strategy for AD.
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