MiR-431 attenuates synaptic plasticity and memory deficits in APPswe/PS1dE9 mice
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE231985 | GEO | 2023/05/15
REPOSITORIES: GEO
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Project description:Objective: The protective components ACE2/Ang(1-7)/MasR of the renin-angiotensin system has been verified to play a role in Alzheimer's disease (AD). Our previous study revealed that enhancement of brain ACE2 activity, an important effector of RAS, by diminazene aceturate (DIZE) ameliorated Alzheimer's disease-like neuropathology and attenuated neuroinflammation in the brain of SAMP8 mice. However, the potential molecular mechanisms by which DIZE modulates neuroinflammation in AD remain unclear. Materials and Methods: APP/PS1 mice were injected intraperitoneally with DIZE (once a day for 30 consecutive days). Cognitive functions, neuronal and synaptic integrity, and inflammation-related markers were assessed by Morris water maze, Nissl staining, Western blot and ELISA, respectively. Since astrocytes played a crucial role in AD-related neuroinflammation whilst miRNAs were reported to participate in modulating inflammatory responses, astrocytes of APP/PS1 mice were then isolated for high-throughput miRNAs sequencing to identify the most differentially expressed miRNA following DIZE treatment. Afterward, the downstream pathway of this miRNA in the anti-inflammatory action of DIZE was investigated using primary astrocytes. Results: The results showed that DIZE alleviated cognitive impairment and neuronal and synaptic damage in APP/PS1 mice. Simultaneously, DIZE suppressed the secretion of pro-inflammatory cytokines and the expression of NLRP3 inflammasome. Importantly, miR-224-5p was significantly up-regulated in the astrocytes of APP/PS1 mice treated by DIZE, and NLRP3 is one of the targets of miR-224-5p. Upregulation of miR-224-5p inhibited the expression of NLRP3 in Aβ1–42-stimulated cells, whereas miR-224-5p downregulation reversed this effect. Furthermore, the inhibition of miR-224-5p could reverse the inhibitory effect of DIZE on astrocytic NLRP3 inflammasome. Conclusion: These results firstly suggested that DIZE inhibits astrocyte-mediated neuroinflammation via miR-224-5p/NLRP3 pathway. Moreover, these results reveal the underlying mechanisms by which DIZE inhibits neuroinflammation under AD condition and uncovers the potential of DIZE in AD treatment.
2023-04-26 | GSE199028 | GEO
Project description:Synaptic dysfunction occurs early in Alzheimer´s disease. However, efforts to protect against these detriments have not been possible due to the inadequate understanding of synaptic signalling pathways involved in the neuropathological disease process. The aim of this study was to elucidate the molecular mechanisms behind Alzheimer´s and synaptic plasticity-related signalling using a multi-omics and in situ imaging approach. We used an Alzheimer´s mouse model (APPswe/PSN1dE9, age of 12 month) (APP/PS1) and compared the changes on the proteome including global phosphorylation and N-linked glycosylation pattern, pathway-focused transcriptome and neurological disease-associated miRNAome with age-matched control mice in the neocortex, hippocampus, olfactory bulb and brainstem. Our analysis showed that signalling pathways related to synaptic functions associated to dendritic spine morphology, neurite outgrowth, long-term potentiaiton, CREB signalling and cytoskeletal dynamics were altered in the APP/PS1 transgenic mice, particular in the neocortex and olfactory bulb. This was associated with Aβ plaques and neurofibrillary tangle formation as well as microglial clustering in all brain regions except brainstem. The responses may be epigenetically modulated by the interaction with a number of miRNAs. We suggest that the alterations in synaptic plasticity-related signalling are associated to neurocognitive dysfunctions that resemble the situtation in human AD patients.
2016-05-11 | PXD003312 | Pride
Project description:Objective: Emerging evidence suggested that brain angiotensin-(1-7) (Ang-(1-7)) deficiency contributed to the pathogenesis of Alzheimer’s disease (AD). Meanwhile, our previous studies revealed that restoration of brain Ang-(1-7) levels provided neuroprotection by inhibition of inflammatory responses during AD progress. However, the potential molecular mechanisms by which Ang-(1-7) modulates neuroinflammation remain unclear. Materials and Methods: APP/PS1 mice were injected intraperitoneally with AVE0991 (a nonpeptide analogue of Ang-(1-7)) once a day for 30 consecutive days. Cognitive functions, neuronal and synaptic integrity, and inflammation-related markers were assessed. Since astrocytes played a crucial role in AD-related neuroinflammation whilst long noncoding RNAs (lncRNAs) were reported to participate in modulating inflammatory responses, astrocytes of APP/PS1 mice were then isolated for high-throughput lncRNA sequencing to identify the most differentially expressed lncRNA following AVE0991 treatment. Afterward, the downstream pathway of this lncRNA in the anti-inflammatory action of AVE0991 were investigated using primary astrocytes. Results: The protection of AVE0991 against cognitive impairment and neuronal and synaptic damage in APP/PS1 mice was confirmed. For the first time, we demonstrated that AVE0991 suppressed astrocytic NLRP3 inflammasome-mediated neuroinflammation via a lncRNA SNHG14-dependent manner. SNHG14 acted as a sponge of miR-223-3p while NLRP3 represented a direct target of miR-223-3p in astrocytes. In addition, miR-223-3p participated in the AVE0991-induced suppression of astrocytic NLRP3 inflammasome. Conclusion: These results suggest that AVE0991 inhibits astrocyte-mediated neuroinflammation via SNHG14/miR-223-3p/NLRP3 pathway. Moreover, these results reveal the underlying mechanisms by which Ang-(1-7) inhibits neuroinflammation under AD condition and uncovers the potential of its nonpeptide analogue AVE0991 in AD treatment.
2021-12-29 | GSE184967 | GEO
Project description:In a series of slice electrophysiology experiments, we demonstrated that female APPSwe-Psen1dE9 Alzheimer's disease model mice show greater impairments in hippocampal synaptic plasticity than male mice of the same age and genotype. Female APP/PS1 mice also showed greater impairments in behavioural associative memory, higher amyloid plaque burden and increased microglial activation in the hippocampus than males at age 4-5 months. We thus profiled hippocampal mRNA from these mice to investigate the underlying molecular mechanisms. Compared to wild-type mice of the same sex, we found that female APP/PS1 mice showed a greater upregulation of microglial and inflammatory genes than males. Moreover, downregulation of genes associated with memory and plasticity was observed uniquely in female APP/PS1 mice. These data provide insight into the potential mechanisms of the greater prevalence and faster progression of AD in females.
2021-10-30 | GSE186710 | GEO
Project description:Neuroinflammation is a major contributor to disease progression in Alzheimer´s disease (AD) and is characterized by the activity of brain resident glial cells, in particular microglia cells. However, there is increasing evidence that peripheral immune cells infiltrate the brain at certain stages of AD progression and shape disease pathology. We recently identified CD8+ T-cells in the brain parenchyma of APP-PS1 transgenic mice being tightly associated with microglia as well as with neuronal structures. The functional role of CD8+ T-cells in the AD brain is however completely unexplored. Here, we demonstrate increased numbers of intra-parenchymal CD8+ T-cells in human AD post-mortem hippocampus, which was replicated in APP-PS1 mice. Also, aged WT mice show a remarkable infiltration of CD8+ T-cells, which was more pronounced and had an earlier onset in APP-PS1 mice. To address their functional relevance in AD, we successfully ablated the pool of CD8+ T-cells in the blood, spleen and brain from 12 months-old APP-PS1 and WT mice for a total of 4 weeks using an anti-CD8 antibody treatment. While the treatment at this time of disease stage did neither affect the cognitive outcome nor plaque pathology, RNAseq analysis of the hippocampal transcriptome from APP-PS1 mice lacking CD8+ T-cells revealed highly altered neuronal- and synapse-related gene expression including an up-regulation for neuronal immediate early genes (IEGs) such as the Activity Regulated Cytoskeleton Associated Protein (Arc) and the Neuronal PAS Domain Protein 4 (Npas4). Gene ontology enrichment analysis illustrated that the biological processes “regulation of neuronal synaptic plasticity” and the cellular components “postsynapses” were over-represented upon CD8+ T-cell ablation. Additionally, Kegg pathway analysis showed up-regulated pathways for “calcium signaling”, “long-term potentiation”, “glutamatergic synapse” and “axon guidance”. Therefore, we conclude that CD8+ T-cells infiltrate the aged and AD brain and that brain CD8+ T-cells might directly contribute to neuronal dysfunction in modulating synaptic plasticity. Further analysis will be essential to uncover the exact mechanism of how CD8+ T-cells modulate the neuronal landscape and thereby contribute to AD pathology.
2020-06-22 | GSE149661 | 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:There is accumulating evidence that amyloid beta and tau proteins may act synergistically to cause synapse and neural circuit degeneration in Alzheimer’s disease. In order to study this, we designed a new mouse model which lacks endogenous mouse tau, but expresses both the APP/PS1 transgene, which causes well-characterised plaque-associated synapse loss, and also reversibly expresses wild-type human tau (which can be suppressed with doxycycline). We examined the transcriptional changes in the frontal cortex of this mouse model, along with behaviour, pathology, synaptic plasticity, synapse degeneration and accumulation of amyloid beta and tau at synapses, and compared with littermate control genotypes: those lacking endogenous mouse tau, those lacking endogenous mouse tau but expressing the APP/PS1 transgene only, and those lacking endogenous mouse tau but reversibly expressing wild-type human tau only.
2019-11-12 | E-MTAB-7856 | biostudies-arrayexpress
Project description:We performed next-generation RNA sequencing (RNA-seq) using brain tissue from 23 months old non-transgenic (NTG), non-treated and CP2 (mitochondrial complex I inhibitor)-treated APP/PS1 (mouse model of Alzheimer`s disease). By comparing transcriptomic data of NTG and vehicle-treated APP/PS1 mice, we found processes affected by the disease in APP/PS1 such as impaired ATP metabolism, ion transport, nervous system development, synaptic transmission, and inflammation. CP2-treatment in APP/PS1 positively affected genes related to immune system, axonogenesis, dendritic spine morphology, synaptic function, among the others. These data demonstrate that pathways improved by CP2 treatment in APP/PS1 mice comprise major pathways essential for therapeutic efficacy in Alzheimer`s disease.
2020-10-31 | GSE149248 | GEO
Project description:The etiology of Alzheimer's disease (AD) has been intensively studied. However, little is known about the molecular alterations in early-stage and late-stage AD. Hence, we performed RNA sequencing and assessed differentially expressed genes (DEGs) in the hippocampus of 18-month and 7-month-old APP/PS1 mice. Moreover, the DEGs induced by treatment with nicotine, the nicotinic acetylcholine receptor agonist that is known to improve cognition in AD, were also analyzed in old and young APP/PS1 mice. When comparing old APP/PS1 mice with their younger littermates, we found an upregulation in genes associated with calcium overload, immune response, cancer, and synaptic function; the transcripts of 14 calcium ion channel subtypes were significantly increased in aged mice. In contrast, the downregulated genes in aged mice were associated with ribosomal components, mitochondrial respiratory chain complex, and metabolism. Through comparison with DEGs in normal aging from previous reports, we found that changes in calcium channel genes remained one of the prominent features in aged APP/PS1 mice. Nicotine treatment also induced changes in gene expression. Indeed, nicotine augmented glycerolipid metabolism, but inhibited PI3K and MAPK signaling in young mice. In contrast, nicotine affected genes associated with cell senescence and death in old mice. Our study suggests a potential network connection between calcium overload and cellular signaling, in which additional nicotinic activation might not be beneficial in late-stage AD
2019-09-10 | GSE86828 | GEO
Project description:The Ketogenic Diet (KD) has been shown by two groups to improve cognition, memory and longevity in aged C57BL6 mice. We tested the impact of 7 months feeding the isocaloric Ketogenic Diet (KD) vs. the isocaloric standard carbohydrate-rich control diet (CD) in a mouse model of Alzheimer’s disease, APP/PS1. The KD vs. CD diets produced no significant changes in fat mass, lean Mass, or total body mass, or A-beta levels in brain. While the CD-fed APP/PS1 mice demonstrated the expected loss of Long-Term-Potentiation (LTP), LTP was completely preserved in KD-fed APP/PS1 mice to wild-type levels. RNAseq was carried out from these CD and KD-fed mouse brains, in the resulting Ingenuity Pathway Analysis the top 6 pathways induced in APP/PS1 brains on KD related to Synaptic Plasticity. Multiple biochemical elements of this pathway were evaluated in CD and KD hippocampi. Significant elevations of phospho-Erk and phospho-CREB were observed in KD vs. CD, and significant elevations of BDNF were observed in KD vs. CD females. The major effector of KD’s benefit is considered to be beta-hydroxybutyrate (BHB). BHB levels were significantly elevated in KD vs. CD mice, and fasting BHB levels were higher in females than male. We suggest that KD may rescue LTP not by reducing A-beta amyloid levels, but through higher BHB that may support greater synaptic plasticity in the face of A-beta amyloid synaptic challenge.
2023-12-31 | GSE230469 | GEO