Deletion of small GTPase H-Ras rescues memory deficits and ameliorates amyloid pathology in transgenic Alzheimer’s mice
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE180103 | GEO | 2022/11/01
REPOSITORIES: GEO
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Project description:BACKGROUND:Amyloid ? (A?)-directed immunotherapy has shown promising results in preclinical and early clinical Alzheimer's disease (AD) trials, but successful translation to late clinics has failed so far. Compelling evidence suggests that post-translationally modified A? peptides might play a decisive role in onset and progression of AD and first clinical trials targeting such A? variants have been initiated. Modified A? represents a small fraction of deposited material in plaques compared to pan-A? epitopes, opening up pathways for tailored approaches of immunotherapy. Here, we generated the first monoclonal antibodies that recognize L-isoaspartate-modified A? (isoD7-A?) and tested a lead antibody molecule in 5xFAD mice. METHODS:This work comprises a combination of chemical and biochemical techniques as well as behavioral analyses. A? peptides, containing L-isoaspartate at position 7, were chemically synthesized and used for immunization of mice and antibody screening methods. Biochemical methods included anti-isoD7-A? monoclonal antibody characterization by surface plasmon resonance, immunohistochemical staining of human and transgenic mouse brain, and the development and application of isoD7-A? ELISA as well as different non-modified A? ELISA. For antibody treatment studies, 12?mg/kg anti-isoD7-A? antibody K11_IgG2a was applied intraperitoneally to 5xFAD mice for 38?weeks. Treatment controls implemented were IgG2a isotype as negative and 3D6_IgG2a, the parent molecule of bapineuzumab, as positive control antibodies. Behavioral studies included elevated plus maze, pole test, and Morris water maze. RESULTS:Our advanced antibody K11 showed a KD in the low nM range and?>?400fold selectivity for isoD7-A? compared to other A? variants. By using this antibody, we demonstrated that formation of isoD7-A? may occur after formation of aggregates; hence, the presence of the isoD7-modification differentiates aged A? from newly formed peptides. Importantly, we also show that the Tottori mutation responsible for early-onset AD in a Japanese pedigree is characterized by massively accelerated formation of isoD7-A? in cell culture. The presence of isoD7-A? was verified by K11 in post mortem human cortex and 5xFAD mouse brain tissue. Passive immunization of 5xFAD mice resulted in a significant reduction of isoD7-A? and total A? in brain. Amelioration of cognitive impairment was demonstrated by Morris water maze, elevated plus maze, pole, and contextual fear conditioning tests. Interestingly, despite the lower abundance of the isoD7-A? epitope, the application of anti-isoD7-A? antibodies showed comparable treatment efficacy in terms of reduction of brain amyloid and spatial learning but did not result in an increase of plasma A? concentration as observed with 3D6 treatment. CONCLUSIONS:The present study demonstrates, for the first time, that the antibody-mediated targeting of isoD7-modified A? peptides leads to attenuation of AD-like amyloid pathology. In conjunction with previously published data on antibodies directed against pGlu-modified A?, the results highlight the crucial role of modified A? peptides in AD pathophysiology. Hence, the results also underscore the therapeutic potential of targeting modified amyloid species for defining tailored approaches in AD therapy.
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Project description:Alzheimer's disease (AD) is a progressive neurodegenerative disease that causes substantial public health care burdens. Intensive efforts have been made to find effective and safe disease-modifying treatment and symptomatic intervention alternatives against AD. Smart Soup (SS), a Chinese medicine formula composed of Rhizoma Acori Tatarinowii (AT), Poria cum Radix Pini (PRP) and Radix Polygalae (RP), is a typical prescription against memory deficits. Here, we assessed the efficacy of SS against AD. Oral administration of SS ameliorated the cognitive impairment of AD transgenic mice, with reduced A? levels, retarded A? amyloidosis and reduced A?-induced gliosis and neuronal loss in the brains of AD mice. Consistently, SS treatment reduced amyloid-related locomotor dysfunctions and premature death of AD transgenic Drosophila. Mechanistic studies showed that RP reduced A? generation, whereas AT and PRP exerted neuroprotective effects against A?. Taken together, our study indicates that SS could be effective against AD, providing a practical therapeutic strategy against the disease.
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Project description:Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder and is triggered via abnormal accumulation of amyloid-? peptide (A?). Aggregated A? is responsible for disrupting calcium homeostasis, inducing neuroinflammation, and promoting neurodegeneration. In this study, we generated curcuminoid submicron particle (CSP), which reduce the average size to ~60 nm in diameter. CSP had elevated the bioavailability in vivo and better neuroprotective effect against oligomeric A? than un-nanosized curcuminoids in vitro. Two months of CSP consumption reversed spatial memory deficits and the loss of a calcium binding protein calbindin-D28k in the hippocampus of AD mouse model. In addition, CSP consumption lowered amyloid plaques and astrogliosis in vivo and enhanced microglial A? phagocytosis in vitro, implying that the beneficial effects of CSP also mediated via modulating neuroinflammation and enhancing amyloid clearance. Taken together, our study demonstrated the protective effects of CSP toward ameliorating the memory impairment and pathological deficits in AD mouse model.
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Project description:[This corrects the article DOI: 10.1371/journal.pone.0111215.].
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Project description:We have previously demonstrated that Sirt3 gene deletion, a model for metabolic syndrome, leads to brain mitochondrial dysfunction and neuroinflammation. We also reported that silencing of Sirt3 gene in APP/PS1 mice results in exacerbation of insulin resistance, neuroinflammation and β amyloid plaque deposition. To further understand how metabolic syndrome and amyloid pathology interact, we performed RNA-seq analysis of the brain samples from wild type, Sirt3-/- , APP/PS1 and APP/PS1/Sirt3-/- mice.
2022-10-24 | GSE216081 | GEO
Project description:RAS proteins are key regulators of growth factor signaling. Here we show that deletion of all RAS genes in mouse embryonic stem cells (mES) leads to an overall reduction in protein translation, limits their long-term proliferative capacity and incapacitates them to differentiate. Deletion of ERF, a transcriptional repressor of the ETS family, rescues proliferation and differentiation of RAS-deficient mES cells and allows the development of teratomas lacking RAS genes. Upon RAS deletion, ERF translocates to the nucleus where it binds to multiple enhancers of key RAS targets suppressing their expression. We also reveal recurrent losses of ERF in cancer and show that ERF deficiency increases the resistance of cancer cells to pharmacological inhibition of the RAS pathway. In summary, we here reveal a central role for ERF in coordinating RAS signaling in pluripotent cells, and identify a synthetic viable interaction that bypasses the requirement for RAS proteins in mammalian cells.
2018-05-08 | GSE99476 | GEO
Project description:RAS proteins are key regulators of growth factor signaling. Here we show that deletion of all RAS genes in mouse embryonic stem cells (mES) leads to an overall reduction in protein translation, limits their long-term proliferative capacity and incapacitates them to differentiate. Deletion of ERF, a transcriptional repressor of the ETS family, rescues proliferation and differentiation of RAS-deficient mES cells and allows the development of teratomas lacking RAS genes. Upon RAS deletion, ERF translocates to the nucleus where it binds to multiple enhancers of key RAS targets suppressing their expression. We also reveal recurrent losses of ERF in cancer and show that ERF deficiency increases the resistance of cancer cells to pharmacological inhibition of the RAS pathway. In summary, we here reveal a central role for ERF in coordinating RAS signaling in pluripotent cells, and identify a synthetic viable interaction that bypasses the requirement for RAS proteins in mammalian cells.
2018-05-08 | GSE99336 | GEO
Project description:Although lots of new drugs are developed to treat Alzheimer's disease (AD), many clinical trials of monotherapy have failed to affect disease progression or symptoms compared with placebo. Recently, scientists believe that combination treatment is more promising than monotherapy. Previous studies found that microRNA-195 (miR-195) was down-regulated in the hippocampi and cortices of chronic brain hypoperfusion (CBH) rats and ApoE4(+/+) mice, and up-regulation of miR-195 can improve the declined cognitive function of ApoE4(+/+) mice and CBH rats by targeting multi-genes that are related to AD pathology, including amyloid precursor protein (APP) and β-site APP cleaving enzyme 1 (BACE1) genes. However, whether the gain-of-function of miR-195 could improve the impaired learning and memory ability of APP/PS1 transgenic mouse has not been reported. In this study, we stereotaxically injected lentiviral-carried miR-195 into the bilateral hippocampus of 4-month-old (4M) APP/PS1 mice. Morris water maze (MWM) was performed to detect the effect of miR-195 on the cognitive function of APP/PS1 mice after 1M, 2M, and 3M treatment. Western blot was used to detect the expression of APP, BACE1, and AT8. Aβ plagues were quantitatively assessed by immunofluorescence technique. We found that the declined cognitive phenotype of APP/PS1 mice occurred at the age of 6M, not at the age of 5M. And treatment of Lv-pre-miR-195 to APP/PS1 mice for 1M did not achieve any changes. Although Lv-pre-miR-195 treatment for 2M improved the declined learning ability of APP/PS1 mice, it did not affect the memory functions. However, Lv-pre-miR-195 treatment in APP/PS1 mice for 3M can effectively improve both the learning and memory ability of APP/PS1 mice at the age of 7M. Further studies demonstrated that gain-of-function of miR-195 by Lv-pre-miR-195 injection could inhibit the increased APP and AT8 expression of APP/PS1 mice but did not affect BACE1 level that was not changed in both hippocampus and cortex. By counting the number of Aβ plaques of different sizes, we found that Lv-pre-miR-195 treatment mainly reduced the number of Aβ plaques of less than 20 μm, but did not affect the number of Aβ plaques of greater than 50 μm. Taken together, the gain-of -function of miR-195 in the hippocampus can improve the cognition of APP/PS1 mice, probably by blocking the formation of Aβ plagues rather than clearing those that have already formed Aβ plagues.
| S-EPMC8109030 | biostudies-literature
Project description:Background5-Lipoxygenase (5-LO) is a protein widely distributed in the central nervous system where it modulates amyloidosis and memory impairments in transgenic mouse models of Alzheimer's disease. However, no data are available as to whether 5-LO is elevated in human tauopathy or if it directly influences tau pathology in a relevant model of the disease.MethodsWe assayed 5-LO levels in brain samples from patients with tauopathy and transgenic tau mice, and we evaluated the effect of 5-LO pharmacologic inhibition on the phenotype of these mice.ResultsThe 5-LO protein is upregulated in human tauopathy and transgenic tau mice brains. Pharmacologic blockade of 5-LO in tau mice resulted in significant memory improvement, rescue of synaptic integrity and dysfunction, and reduction of tau pathology via a cdk5-dependent mechanism.ConclusionsThese results establish a key role of 5-LO in the development of the tau pathology phenotype and demonstrate it to be a novel viable therapeutic target for the pharmacologic treatment of human tauopathy.
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Project description:High-fat diet and certain dietary patterns are associated with higher incidence of sporadic Alzheimer's disease (AD) and cognitive decline. However, no specific therapy has been suggested to ameliorate the negative effects of high fat/high cholesterol levels on cognition and amyloid pathology. Here we show that in 9-month-old APP23 mice, a high-fat/high-cholesterol (HF) diet provided for 4 months exacerbates the AD phenotype evaluated by behavioral, morphological, and biochemical assays. To examine the therapeutic potential of liver X receptor (LXR) ligands, APP23 mice were fed HF diet supplemented with synthetic LXR agonist T0901317 (T0). Our results demonstrate that LXR ligand treatment causes a significant reduction of memory deficits observed during both acquisition and retention phases of the Morris water maze. Moreover, the effects of T0 on cognition correlate with AD-like morphological and biochemical parameters. We found a significant decrease in amyloid plaque load, insoluble Abeta and soluble Abeta oligomers. In vitro experiments with primary glia demonstrate that Abca1 is essential for the proper lipidation of ApoE and mediates the effects of T0 on Abeta degradation by microglia. Microdialysis experiments performed on awake freely moving mice showed that T0 decreased Abeta levels in the interstitial fluid of the hippocampus, supporting the conclusion that this treatment increases Abeta clearance. The data presented conclusively shows that LXR activation in the context of a metabolic challenge has critical effects on AD phenotype progression by attenuating Abeta deposition and facilitating its clearance.
| S-EPMC2883862 | biostudies-literature