Mitophagy ameliorates Aβ and p-Tau pathologies, and cognitive deficits, in experimental models of Alzheimer’s disease
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE111737 | GEO | 2018/11/26
REPOSITORIES: GEO
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Project description:Despite diverging levels of amyloid-β (Aβ) and TAU pathology, different mouse models, as well as sporadic AD patients show predictable patterns of episodic memory loss. MiRNA deregulation is well established in AD brain but it is unclear whether Aβ or Tau pathology drives those alterations and whether miRNA changes contribute to cognitive decline. Therefore miRNAseq was performed on the hippocampus of APPswe/PS1L166P and Thy-TAU22 mice and their respective wild-type littermates when they were cognitively intact (4 months) and impaired (10 months). We found 6 miRNAs that are commonly upregulated between APPtg and TAUtg mice, and four of these were also altered in AD patients. All 6 miRNAs are strongly enriched in neurons as verified by in situ hybridization.
2018-10-13 | GSE110743 | GEO
Project description:INTRODUCTION Alzheimer’s disease (AD) is an advanced neurodegenerative disorder characterized by progressive impairment in both memory loss and cognitive capacities, which resulting in severe dementia [1]. The pathogenesis of AD is complicated and poorly understood. According to the World Alzheimer Report 2018, it is estimated that AD affects at least 50 million persons throughout the world, and the number of people with AD will double nearly every 20 years [2]. Over the past decade, various theories have been developed for the neuropathological level of AD, but the most popular distinct pathological hallmarks is extracellular accumulation of amyloid beta (Aβ) plaques, as well as the neurofibrillary tangles (NFTs) composed of the hyperphosphorylated tau in the form of in the select brain regions [3]. The other factors including mitochondrial dysfunction, oxidative stress, brain inflammation and neurotransmitter disturbances pathology have been recognized as a contributing factor in the pathogenesis of AD [4]. To date, only symptomatic therapies are available for AD patients. Cholinesterase inhibitors (CIs) are approved for mild to moderate AD patients, and memantine is the only one N-methyl-D-aspartate receptor (NMDAR) antagonist has been approved for moderate to severe AD [5]. NMDAR is a glutamate ionotropic receptor, they display high Ca2+ permeability and voltage-dependent block by Mg2+[6]. In AD patients, NMDARs could be overactivated due to increasing glutamate release from presynaptic neurons. Overactived NMDARs lead first to Ca2+ overload in postsynaptic neurons, followed by desensitization and internalization, resulting in synaptic dysfunction and ultimately cell death [7, 8]. The numerous factors than can influence the levels of endogenous glutamate release in the pathogenesis of AD, deposition of Aβplaques, soluble Aβoligomers, NFTs, mitochondrial dysfunction and oxidative stress have been associated with the higher concentration of glutamate release[9, 10]. Memantine is an uncompetitive, moderate affinity NMDA receptor (NMDAR) antagonist which is used for a further therapeutic option of moderate to severe AD [5]. Its effects have been investigated in a large number of in vitro and in vivo studies, which indicated that memantine can against Aβ-induced glutamate-mediated toxicity, attenuate phosphorylation of tau and reduces level of total precursor protein (APP) in human neuroblastoma SK-N-SH cells [11], and lower Aβ1-42 secretion and plaques in primary cortical neuronal culture cells [9, 12]. Some studies showed that memantine also completely protected against Aβ-induced ROS injure in the primary hippocampal neurons [13]. Studies with transgenic animal models showed that memantine reduced the levels of soluble Aβ1-42, Aβ plaque deposition and lowered the loss of synaptic density in APP/PS1mice [4, 14, 15], and decreased the levels of total tau and hyperphosphorylated tau in 3×Tg-AD mice [3]. Furthermore, memantine altered genes expression in adult rat brain [16], and modulated protein profiles in Down syndrome mice brain [17]. However, no comprehensive study of proteomic characteristics description of 3×Tg-AD transgenic mice under the memantine treatment has been conducted to date as far as we searched. In order to better understand the multiple actions of memantine, we conducted detailed analysis of proteomics and bioinformatics to dissect the molecular mechanisms of memantine for the treatment of AD.
2019-11-12 | PXD012110 | Pride
Project description:Beyond deficits in hippocampal-dependent episodic memory, Alzheimer’s Disease (AD) features sensory impairment in visual cognition consistent with extensive neuropathology in the retina. 12A12 is a monoclonal cleavage specific antibody (mAb) which in vivo selectively neutralizes the AD-relevant, harmful N-terminal 20-22kDa tau fragment(s) (i.e NH2htau) without altering the full-length normal protein. When systemically-injected into Tg2576 mouse model overexpressing a mutant form of Amyloid Precursor Protein (APP), APPK670/671L linked to early-onset familial AD, this conformation-specific tau mAb successfully neutralizes the NH2htau accumulating both in their brain and retina and, thus, markedly alleviates the phenotype-associated signs. By means of combined biochemical and metabolic and transcriptomic experimental approach, we report that 12A12mAb downregulates the steady state expression levels of APP and Beta-Secretase 1 (BACE-1) and, thus, limits the Amyloid beta (Aβ) production both in hippocampus and retina from this AD animal model. The endocytic (BIN1, RIN3) and bioenergetic (glycolisis and mitochondria) pathways controlling the cellular fate of APP processing towards the amyloidogenic route subserve the local, antibody-mediated anti-amyloidogenic action in vivo. Our results show for the first time that similar molecular and metabolic retino-cerebral pathways are modulated in coordinated fashion in response to 12A12mAb treatment to tackle the neurosensorial Aβ accumulation in AD neurodegeneration.
2023-06-14 | GSE223593 | GEO
Project description:The pathophysiology of Alzheimer’s disease (AD) is multifactorial with characteristic extracellular accumulation of amyloid-beta (Aβ) and intraneuronal aggregation of hyperphosphorylated tau in the brain. Development of disease-modifying treatment for AD has been challenging. Recent studies suggest that deleterious alterations in neurovascular cells happens in parallel with Aβ accumulation, inducing tau pathology and necroptosis. Therefore, therapies targeting cellular Aβ and tau pathologies may provide a more effective strategy of disease intervention. Tetramethylpyrazine nitrone (TBN) is a nitrone derivative of tetramethylpyrazine, an active ingredient from Ligusticum wallichii Franchat (Chuanxiong). We previously showed that TBN is a potent scavenger of free radicals with multi-targeted neuroprotective effects in rat and monkey models of ischemic stroke. The present study aimed to investigate the anti-AD properties of TBN. We employed AD-related cellular model (N2a/APPswe) and transgenic mouse model (3×Tg-AD mouse) for mechanistic and behavioral studies. Our results showed that TBN markedly improved cognitive functions and reduced Aβ and hyperphosphorylated tau levels in mouse model. Further investigation of the underlying mechanisms revealed that TBN promoted non amyloidogenic processing pathway of amyloid precursor protein (APP) in N2a/APPswe in vitro. Moreover, TBN preserved synapses from dendritic spine loss and upregulated synaptic protein expressions in 3×Tg-AD mice. Proteomic analysis of 3×Tg-AD mouse hippocampal and cortical tissues showed that TBN induced neuroprotective effects through modulating mitophagy, MAPK and mTOR pathways. In particular, TBN significantly upregulated PINK1, a key protein for mitochondrial homeostasis, implicating PINK1 as a potential therapeutic target for AD. In summary, TBN improved cognitive functions in AD-related mouse model, inhibited Aβ production and tau hyperphosphorylation, and rescued synaptic loss and neuronal damage. Multiple mechanisms underlie the anti-AD effects of TBN including the modulation of APP processing, mTOR signaling and PINK1-related mitophagy.
2023-05-10 | PXD039514 | Pride
Project description:Background:Episodic memory loss is a prominent clinical manifestation of Alzheimer's disease(AD), which is closely related to tau pathology and hippocampal impairment. Given the heterogeneity of brain neurons, the precise role of different brain neurons in terms of their sensitivity to tau accumulation and contribution to AD-like social memory loss remains unclear and requires further investigation. Methods: We investigated the effects of AD-like tau pathology by Tandem mass tag proteomic and phosphoproteomic experiments, social behavioral test, hippocampal electrophysiology, immunofluorescent staining and in vivo optical fiber recording of GCaMP6f and iGABASnFR. Additionally, we utilized optogenetics and administered ursolic acid (UA) via oral gavage to examine their effects on social memory in mice. Results: By proteomic and phosphoproteomic analyses, we identified the characteristics of ventral hippocampal CA1 (vCA1) under both physiological conditions and AD-like tau pathology. As tau progressively accumulated, not dorsal CA1 (dCA1), but vCA1, especially its excitatory and PV neurons, were fully filled with mislocated and phosphorylated tau. Overexpression of human Tau (hTau) in excitatory and PV neurons respectively mimicked AD-like tau accumulation, significantly inhibited the neuronal excitability and suppressed distinct discrimination-associated firings of these neurons within vCA1. Photoactivating excitatory and PV neurons in vCA1 at specific rhythm and time-window efficiently ameliorated tau-impaired social memory. Significantly, one-month administration of UA efficiently decreased tau accumulation via autophagy in a TFEB (transcription factor EB)-dependent manner and recovered vCA1 microcircuit to ameliorate tau-impaired social memory.Conclusion: This study elucidated distinct protein and phosphoprotein networks between dCA1 and vCA1, and highlighted the susceptibility of the vCA1 microcircuit to AD-like tau accumulation. Notably, our novel findings regarding the efficacy of UA in reducing tau load and targeting the vCA1 microcircuit may provide a promising strategy for AD treatment in the future.
2023-07-19 | PXD043883 | iProX
Project description:Amyloid-beta (Aβ) deposition in the brain, is closely linked to development of Alzheimer’s disease (AD). Unfortunately, therapies specifically targeting Aβ deposition have failed to reach their primary clinical endpoints, emphasizing the need to broaden the search strategy for identification of alternative therapeutic targets/mechanisms. Transglutaminase (TG2) catalyses posttranslational modifications, is present in characteristic AD lesions and has AD-associated proteins, including Aβ, tau and apolipoprotein E. However, an unbiased overview of TG2 interactors (TG2 interactome) and the cellular pathways of which these interactors are part in control and AD brain is lacking. Here, anticipating future studies in AD brain, we aimed to identify these interactors and their pathways using a crossbred of the AD-mimicking APP23 mouse model with wildtype and TG2-/- mice. We found that absence of TG2 had no (statistically) significant effect on Aβ pathology, soluble brain levels of Aβ1-40, Aβ1-42, and mRNA levels of TG2 family members compared to APP23 mice. Quantitative proteomics and network analysis revealed a large cluster of TG2 interactors with synaptic transmission/assembly and cell adhesion typical of AD in the APP23 brain. Comparative proteomics were in line with these observations as it also revealed association of proteins of both pathways to be linked to TG2 in APP23 brains Together, our data showed that TG2 deletion led to considerable network alterations consistent with a role of TG2 in (dys)regulation of synaptic transmission and cell adhesion in APP23 brains.
2022-02-22 | PXD030354 | Pride
Project description:Deposition of amyloid beta (Aβ) and hyperphosphorylated tau along with glial cell-mediated neuroinflammation are prominent pathogenic hallmarks of Alzheimer’s disease (AD). In recent years, impairment of autophagy has been found to be another important feature contributing to AD progression. Therefore, the potential of the autophagy activator spermidine, a small body-endogenous polyamine often used as dietary supplement, was assessed on Aβ pathology and glial cell-mediated neuroinflammation. Oral treatment of the amyloid prone AD-like APPPS1 mice with spermidine reduced neurotoxic soluble Aβ and decreased AD-associated neuroinflammation during disease progression. Mechanistically, single nuclei sequencing revealed AD-associated microglia to be the main target of spermidine. This microglia population was characterized by increased AXL levels and expression of genes implicated in cell migration and phagocytosis. Our data highlight that the autophagy activator spermidine holds the potential to enhance Aβ degradation and to counteract glia-mediated neuroinflammation in AD pathology.
2022-07-04 | GSE206202 | GEO
Project description:Alzheimer’s disease (AD) is an age-related neurodegenerative disorder characterized by accumulation of amyloid β-peptide (Aβ) plaques in the brain and decreased cognitive function leading to dementia. We determined if hydroxyurea (HU), a ribonucleotide reductase inhibitor known to activate adaptive cellular stress responses in fibroblasts, could protect rat hippocampal neurons against oxidative-, excitatory-, mitochondrial-, and Aβ-induced stress and if HU treatment could improve learning and memory in a mouse model of AD (APP/PS1 double mutant transgenic mice). HU treatment attenuated the loss of cell viability induced by treatment of hippocampal neurons with hydrogen peroxide, glutamate, rotenone, and Aβ1-42. HU treatment also attenuated reductions of mitochondrial reserve capacity, maximal respiration, and cellular ATP content induced by hydrogen peroxide treatment. In vivo, treatment of APP/PS1 AD mice with HU (45 mg/kg/day) improved spatial memory performance in the hippocampus-dependent Morris water maze task. In summary, HU provides neuroprotection against toxic insults, improves mitochondrial bioenergetics, and improves spatial memory in a mouse model of AD. HU may offer a new therapeutic approach to delay cognitive decline in AD.
2018-09-10 | GSE111941 | GEO
Project description:Alzheimer’s disease (AD) is an age-related neurodegenerative disorder characterized by accumulation of amyloid β-peptide (Aβ) plaques in the brain and decreased cognitive function leading to dementia. We determined if hydroxyurea (HU), a ribonucleotide reductase inhibitor known to activate adaptive cellular stress responses in fibroblasts, could protect rat hippocampal neurons against oxidative-, excitatory-, mitochondrial-, and Aβ-induced stress and if HU treatment could improve learning and memory in a mouse model of AD (APP/PS1 double mutant transgenic mice). HU treatment attenuated the loss of cell viability induced by treatment of hippocampal neurons with hydrogen peroxide, glutamate, rotenone, and Aβ1-42. HU treatment also attenuated reductions of mitochondrial reserve capacity, maximal respiration, and cellular ATP content induced by hydrogen peroxide treatment. In vivo, treatment of APP/PS1 AD mice with HU (45 mg/kg/day) improved spatial memory performance in the hippocampus-dependent Morris water maze task. In summary, HU provides neuroprotection against toxic insults, improves mitochondrial bioenergetics, and improves spatial memory in a mouse model of AD. HU may offer a new therapeutic approach to delay cognitive decline in AD.
2018-09-10 | GSE111940 | GEO
Project description:The dynamic function of synapses is critical for encoding memories in the brain. Pathogenic tau obstructs glutamatergic synapse function by blocking long-term potentiation (LTP), representing a key mechanism underlying memory impairment in Alzheimer s disease (AD). Here we developed a strategy for KIdney/BRAin (KIBRA)-mediated LTP repair in neurons with pathogenic tau using the C-terminus of KIBRA (CT-KIBRA). We show that CT-KIBRA restores LTP and memory in transgenic mice expressing human tau that mimics pathogenic hyperacetylated tau found in AD and other tauopathies. CT-KIBRA did not alter tau levels or prevent tau-induced synapse loss in the transgenic mouse brain, instead, we show that CT-KIBRA binds to and stabilizes protein kinase M zeta (PKM zeta) to maintain plasticity and memory despite tau pathogenesis. Further, in humans we established that KIBRA levels in brain and cerebrospinal fluid correlate with tau and cognitive impairment in tauopathies. Our study provides evidence to support KIBRA as a tauopathy-related synaptic biomarker and a synapse repair therapeutic to ameliorate cognitive impairment.
2022-10-11 | MSV000090510 | MassIVE