mTOR: Alzheimer's disease prevention for APOE4 carriers

Lin, Ai Ling; Butterfield, D. Allan; Richardson, Arlan

doi:10.18632/oncotarget.10349

Cited by 6 publications

(3 citation statements)

References 7 publications

(11 reference statements)

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“…Even when administered three months post injury, inulin’s effects still had a positive impact on recovery through attenuating harmful effects caused by CHI in the gut microbiome, systemic metabolism, and brain vascular and structural function. This is in line with previous findings that protecting brain metabolism is important to mitigate CNS injury and age-related neurodegenerative disorders [ 6 , 48 – 55 ]. In the future, we could also use other MRI neuroimaging methods to determining brain metabolic and vascular functions that may be influenced by inulin, including levels of essential brain metabolites [ 56 ], cerebral metabolic rate of oxygen [ 57 , 58 ], and cerebral blood volume [ 59 ].…”

Section: Discussionsupporting

confidence: 93%

Inulin Supplementation Mitigates Gut Dysbiosis and Brain Impairment Induced by Mild Traumatic Brain Injury during Chronic Phase

Yanckello

Fanelli

McCulloch

et al. 2022

Journal of Cellular Immunology

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Mild traumatic brain injury (mTBI) has been shown to acutely alter the gut microbiome diversity and composition, known as dysbiosis, which can further exacerbate metabolic and vascular changes in the brain in both humans and rodents. However, it remains unknown how mTBI affects the gut microbiome in the chronic phase recovery (past one week post injury). It is also unknown if injury recovery can be improved by mitigating dysbiosis. The goal of the study is to fill the knowledge gap. First, we aim to understand how mTBI alters the gut microbiome through the chronic period of recovery (3 months post injury). In addition, as the gut microbiome can be modulated by diet, we also investigated if prebiotic inulin, a fermentable fiber that promotes growth of beneficial bacteria and metabolites, would mitigate dysbiosis, improve systemic metabolism, and protect brain structural and vascular integrity when administered after 3 months post closed head injury (CHI). We found that CHI given to male mice at 4 months of age induced gut dysbiosis which peaked at 1.5 months post injury, reduced cerebral blood flow (CBF) and altered brain white matter integrity. Interestingly, we also found that Sham mice had transient dysbiosis, which peaked 24 hours after injury and then normalized. After 8 weeks of inulin feeding, CHI mice had increased abundance of beneficial/anti-inflammatory bacteria, reduced abundance of pathogenic bacteria, enriched levels of short-chain fatty acids, and restored CBF in both hippocampi and left thalamus, compared to the CHI-control fed and Sham groups. Using machine learning, we further identified top bacterial species that separate Sham and CHI mice with and without the diet. Our results indicate that there is an injury- and time-dependent dysbiosis between CHI and Sham mice; inulin is effective to mitigate dysbiosis and improve brain injury recovery in the CHI mice. As there are currently no effective treatments for mTBI, the study may have profound implications for developing therapeutics or preventive interventions in the future.

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Section: Discussionsupporting

confidence: 93%

Inulin Supplementation Mitigates Gut Dysbiosis and Brain Impairment Induced by Mild Traumatic Brain Injury during Chronic Phase

Yanckello

Fanelli

McCulloch

et al. 2022

Journal of Cellular Immunology

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“…Because we observed similar biological functions altered between the E4/E4 vs E3/E3 controls, it is likely E4 genotype drives early cerebrovascular abnormalities in the aging process, which increases the vulnerability of the cerebrovasculature to further damage in AD pathogenesis. To corroborate our findings, previous studies have suggested that EIF2 α and mTOR pathways are major players in the APOE4 mediated cellular effects, and have been explored as therapeutic targets in mouse models of AD [72][73][74][75][76].…”

Section: Apoe Specific Effects On Cerebrovascular Proteome In Adsupporting

confidence: 85%

APOE genotype dependent molecular abnormalities in the cerebrovasculature of Alzheimer’s disease and age-matched non-demented brains

et al. 2021

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Cerebrovascular dysfunction is a hallmark feature of Alzheimer's disease (AD). One of the greatest risk factors for AD is the apolipoprotein E4 (E4) allele. The APOE4 genotype has been shown to negatively impact vascular amyloid clearance, however, its direct influence on the molecular integrity of the cerebrovasculature compared to other APOE variants (APOE2 and APOE3) has been largely unexplored. To address this, we employed a 10-plex tandem isobaric mass tag approach in combination with an ultra-high pressure liquid chromatography MS/MS (Q-Exactive) method, to interrogate unbiased proteomic changes in cerebrovessels from AD and healthy control brains with different APOE genotypes. We first interrogated changes between healthy control cases to identify underlying genotype specific effects in cerebrovessels. EIF2 signaling, regulation of eIF4 and 70S6K signaling and mTOR signaling were the top significantly altered pathways in E4/E4 compared to E3/E3 cases. Oxidative phosphorylation, EIF2 signaling and mitochondrial dysfunction were the top significant pathways in E2E2 vs E3/E3cases. We also identified AD-dependent changes and their interactions with APOE genotype and found the highest number of significant proteins from this interaction was observed in the E3/E4 (192) and E4/E4 (189) cases. As above, EIF2, mTOR signaling and eIF4 and 70S6K signaling were the top three significantly altered pathways in E4 allele carriers (i.e. E3/E4 and E4/E4 genotypes). Of all the cerebrovascular cell-type specific markers identified in our proteomic analyses, endothelial cell, astrocyte, and smooth muscle cell specific protein markers were significantly altered in E3/E4 cases, while endothelial cells and astrocyte specific protein markers were altered in E4/E4 cases. These proteomic changes provide novel insights into the longstanding link between APOE4 and cerebrovascular dysfunction, implicating a role for impaired autophagy, ER stress, and mitochondrial bioenergetics. These APOE4 dependent changes we identified could provide novel cerebrovascular targets for developing disease modifying strategies to mitigate the effects of APOE4 genotype on AD pathogenesis.

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“…However, Li and colleagues noticed in the hippocampus of APOE4 Wistar rats an activation of the mTORC1 pathway, decreased autophagy, and AD-like alterations [502]. Finally, different studies showed that treatment with rapamycin (inhibitor of mTOR) has a protective effect in the brain of APOE4 transgenic mice and E4FAD mice (5xFAD cross-bred with APOE4 mice) [503][504][505]. These and other previous results have raised interest in rapamycin as a drug of potential interest in AD treatment [506].…”

Section: Implications Of Apoe In Autophagymentioning

confidence: 99%

APOE in the bullseye of neurodegenerative diseases: impact of the APOE genotype in Alzheimer’s disease pathology and brain diseases

Fernández-Calle

Konings

Frontiñán-Rubio

et al. 2022

Mol Neurodegeneration

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ApoE is the major lipid and cholesterol carrier in the CNS. There are three major human polymorphisms, apoE2, apoE3, and apoE4, and the genetic expression of APOE4 is one of the most influential risk factors for the development of late-onset Alzheimer's disease (AD). Neuroinflammation has become the third hallmark of AD, together with Amyloid-β plaques and neurofibrillary tangles of hyperphosphorylated aggregated tau protein. This review aims to broadly and extensively describe the differential aspects concerning apoE. Starting from the evolution of apoE to how APOE's single-nucleotide polymorphisms affect its structure, function, and involvement during health and disease. This review reflects on how APOE's polymorphisms impact critical aspects of AD pathology, such as the neuroinflammatory response, particularly the effect of APOE on astrocytic and microglial function and microglial dynamics, synaptic function, amyloid-β load, tau pathology, autophagy, and cell–cell communication. We discuss influential factors affecting AD pathology combined with the APOE genotype, such as sex, age, diet, physical exercise, current therapies and clinical trials in the AD field. The impact of the APOE genotype in other neurodegenerative diseases characterized by overt inflammation, e.g., alpha- synucleinopathies and Parkinson's disease, traumatic brain injury, stroke, amyotrophic lateral sclerosis, and multiple sclerosis, is also addressed. Therefore, this review gathers the most relevant findings related to the APOE genotype up to date and its implications on AD and CNS pathologies to provide a deeper understanding of the knowledge in the APOE field.

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mTOR: Alzheimer's disease prevention for APOE4 carriers

Cited by 6 publications

References 7 publications

Inulin Supplementation Mitigates Gut Dysbiosis and Brain Impairment Induced by Mild Traumatic Brain Injury during Chronic Phase

Inulin Supplementation Mitigates Gut Dysbiosis and Brain Impairment Induced by Mild Traumatic Brain Injury during Chronic Phase

APOE genotype dependent molecular abnormalities in the cerebrovasculature of Alzheimer’s disease and age-matched non-demented brains

APOE in the bullseye of neurodegenerative diseases: impact of the APOE genotype in Alzheimer’s disease pathology and brain diseases

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