REVIEW | doi:10.20944/preprints202105.0590.v1
Subject: Life Sciences, Biochemistry Keywords: epigenetic mechanisms; learning process; memory formation; cognitive decline; intergenerational epigenetic inheritance; transgenerational epigenetic inheritance, AD
Online: 25 May 2021 (08:37:15 CEST)
During the last years, epigenetic processes have emerged as important factors for many neurodegenerative diseases, such as Alzheimer’s diseases (AD). These complex diseases seem to have a heritable component; however, genome-wide association studies failed to identify the genetic loci involved in the eatiology. So, how can these changes be transmitted from one gen-eration to the next? Answering this question would allow us to understand how the environ-ment can affect human populations for multiple generations and explain the high prevalence of neurodegenerative diseases, such as AD. This review pays particular attention to the relationship among epigenetics, cognition, and neurodegeneration across generations, deepening the under-standing of the relevance of heritability in neurodegenerative diseases. In fact, we highlight some recent examples of EI induced by experiences, focusing on their contribution of processes in learning and memory, to point out new targets for therapeutic interventions. Here, we first describe the prominent role of epigenetic factors in memory processing. Then, we briefly discuss aspects of EI. And ends, we summarize evidence of how epigenetic marks inherited by experi-ence and/or environmental stimuli contribute to cognitive status offspring, since better knowledge of EI can provide clues in the appearance and development of age-related cognitive decline and AD.
ARTICLE | doi:10.20944/preprints202012.0115.v1
Subject: Life Sciences, Biochemistry Keywords: cognitive decline; epigenetics; HFD; aging; SAM0P8; m6A, multigenerational inheritance.
Online: 4 December 2020 (14:54:58 CET)
Environmental factors as maternal high-fat diet (HFD) intake can increase the risk of age-related cognitive decline in adult offspring. The epigenetic mechanisms are a possible link between diet effect and neurodegeneration across generations. Here, we found a significant decrease in triglyceride levels in a high-fat diet with resveratrol HFD+RV group and the offspring. Firstly, we obtained better cognitive performance in HFD+RV groups and their offspring. Molecularly, a significant increase in 5-mC levels, as well as increased gene expression of Dnmt1 and Dnmt3a in HFD+RV F1 group, were found. Furthermore, a significantly increased of m6A levels in HFD+RV F1 were found, and there were changes in gene expression of its enzymes (Mettl3 and Fto). Moreover, we found a decrease in gene expression levels of pro-inflammatory markers such as Il1-β, Il-6, Tnf-α, Cxcl-10, Mcp-1 and Tgf-β1 in HFD+RV and HFD+RV F1 groups. Moreover, there was increased gene expression of neurotrophins such as Ngf and Nt3 and its receptors TrkA and TrkB. Likewise, an increase in protein levels of BDNF and p-Akt in HFD+RV F1 was found. These results suggest that maternal RV supplementation under HFD intake prevents cognitive decline in SAMP8 adult offspring, promoting a reduction in triglycerides and leptin plasma levels, changes in the pro-inflammatory profile, restoring the epigenetic landscape as well as synaptic plasticity.
ARTICLE | doi:10.20944/preprints202001.0244.v1
Subject: Life Sciences, Molecular Biology Keywords: Stress; epigenetics; senescence; cognition; age-related cognitive decline; Alzheimer’s disease; SAMP8; SAMR1; oxidative stress; inflammation; autophagy
Online: 21 January 2020 (11:44:35 CET)
Cognitive and behavioural disturbances are growing public healthcare issue for the modern society, as stressful lifestyle is becoming more and more common. Besides, several pieces of evidence state that environment is crucial in the development of several diseases as well as compromising healthy aging. Therefore, it is important to study the effects of stress on cognition and its relationship with aging. To address these queries, Chronic Mild Stress (CMS) paradigm was used in the senescence-accelerated mouse prone 8 (SAMP8) and resistant 1 (SAMR1). On one hand, we determined the changes produced in the three main epigenetic marks after 4 weeks of CMS treatment, such as a reduction in histone posttranslational modifications and DNA methylation, and up-regulation or down-regulation of several miRNA involved in different cellular processes in mice. In addition, CMS treatment induced reactive oxygen species (ROS) accumulation and loss of antioxidant defence mechanisms, as well as inflammatory signalling activation through NF-κB pathway and astrogliosis markers, like Gfap. Remarkably, CMS altered mTORC1 signalling in both strains, decreasing autophagy only in SAMR1 mice. We found a decrease in glycogen synthase kinase 3 β (GSK-3β) inactivation, hyperphosphorylation of Tau and an increase in sAPPβ protein levels in mice under CMS. Moreover, reduction in the non-amyloidogenic secretase ADAM10 protein levels was found in SAMR1 CMS group. Consequently, detrimental effects on behaviour and cognitive performance were detected in CMS treated mice, affecting mainly SAMR1 mice, promoting a turning to SAMP8 phenotype. In conclusion, CMS is a feasible intervention to understand the influence of stress on epigenetic mechanisms underlying cognition and accelerating senescence.
ARTICLE | doi:10.20944/preprints202101.0162.v1
Subject: Behavioral Sciences, Applied Psychology Keywords: behaviour; BPSD; cognitive decline; aging; SAMP8.
Online: 8 January 2021 (13:48:22 CET)
Alzheimer’s disease (AD) is characterized by cognitive impairment and different non-cognitive deficits called “Behavioural and psychological symptoms of dementia” (BPSD) related to neurotrophin alterations, which differ from those presented in normal aging. Mouse models, both transgenics and inbreed mice models of AD, are a useful tool in understanding the underlying mechanisms of the disease. The SAMP8 (senescence-accelerated mouse prone 8) mice line was generated from AKR/J strain by Professor Toshio Takeda at the University of Kyoto. This strain exhibited a particular early-onset and accelerated aging phenotype. The present study characterizes and provides information regarding the non-cognitive and cognitive states as well as molecular alterations and their relationship, demonstrating the AD-like symptoms presented in older SAMP8 males. The cognitive impairment presented was accompanied by a reduction in sociability and an increase in aggressive as well as anxiety behaviours. Furthermore, changes in three of the most important neurotrophins, such as NT3, BDNF, and NGF as well as their receptors TrkA and TrkB, were found. Thus, the present results reveal new insights in this useful inbred mouse model of neurodegeneration and AD, demonstrating the potential relationship between neurotrophin alterations, cognitive impairment and neuropsychiatric disorders (ND).
ARTICLE | doi:10.20944/preprints202011.0336.v1
Subject: Medicine & Pharmacology, Allergology Keywords: behaviour; BPSD; cognitive decline; aging; correlations; SAMP8
Online: 12 November 2020 (09:46:48 CET)
Alzheimer’s disease (AD) is characterized by cognitive impairment and different non-cognitive deficits called “Behavioural and psychological symptoms of dementia” (BPSD) related to neurotrophin alterations, which differ from those presented in normal aging. Mouse models, both transgenics and inbreed mice models of AD, are a useful tool in understanding the underlying mechanisms of the disease. The SAMP8 (senescence-accelerated mouse prone 8) mice line was generated from AKR/J strain by Professor Toshio Takeda at the University of Kyoto. This strain exhibited a particular early-onset and accelerated aging phenotype. The present study characterizes and provides information regarding the non-cognitive, cognitive and neurotrophin alterations and their correlation, demonstrating the AD-like symptoms presented in older males SAMP8. The cognitive impairment presented was accompanied by a reduction in sociability and an increase in aggressive as well as anxiety behaviours. Furthermore, changes in two of the most important neurotrophins, such as brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3) were found. Thus, the present results reveal new insights in this useful inbred mouse model of neurodegeneration and AD, demonstrating the potential relationship between neurotrophin modifications, cognitive impairment and neuropsychiatric disorders (ND).
ARTICLE | doi:10.20944/preprints202103.0205.v1
Subject: Life Sciences, Biochemistry Keywords: Niemann-Pick type C; soluble epoxide hydrolase; autophagy; cognitive decline; lifespan; inflammation; cholesterol; sphingolipids
Online: 5 March 2021 (21:48:31 CET)
Niemann-Pick type C (NPC) disease is a childhood autosomal recessive inherited rare neuro-degenerative disease, characterized by the accumulation of cholesterol and glycosphingolipids, implicating the autophagy-lysosome system. Inhibition of soluble epoxide hydrolase (sEH), an enzyme that metabolizes epoxy fatty acids (EpFAs) to 1,2-diols, exerts beneficial effects in mod-ulating inflammation and autophagy, critical features of the NPC disease. This study aimed to evaluate the effects of UB-EV-52 a sEH inhibitor (sEHi) in the Npc mouse model by administering for 4 weeks (5 mg/kg/day). Behavioral and cognitive assays (open field test (OF), elevated plus maze (EPM), novel object recognition test (NORT) and object location test (OLT) demonstrated that treatment produced an improvement in short- and long-term memory as well as in spatial memory. Moreover, the treatment with UB-EV-52 increased body weight and the lifespan by 25% and re-duced gene expression of the inflammatory markers (i.e. Il-1β and Mcp1) and improved oxidative stress (OS) markers (iNOS and Hmox1) in the treated Npc mice group. Regarding the autophagic markers, we surprisingly found significantly reduced levels of the ratio LC3B-II/LC3B-I and a significant reduction of brain protein levels of lysosomal-associated membrane protein-1 (LAMP-1) in Npc mice treated group compared to non-treated. Lipid profile analysis showed a significant reduction in lipid storage in the liver and some slight changes in brain tissue in treated Npc mice compared to non-treated groups. Thus, Our results suggest that the pharmacological inhibition of sEH ameliorates most of NPC’s characteristic traits in mice, demonstrating that sEH can be considered a potential therapeutic target for this condition.