Uncovering the role of G9a modulatory landscape promoting neuronal plasticity and neuroprotection in Alzheimer's disease

Author(s):  
Aina Bellver-Sanchis ◽  
Pedro Ávila-López ◽  
Júlia Companys-Alemany ◽  
Gemma Navarro ◽  
Laura Marsal-García ◽  
...  

Abstract Epigenetic alterations are a fundamental pathological hallmark of Alzheimer’s disease (AD). Herein, we uncover the unknown G9a modulation pathways involved in AD, showing the upregulation of G9a and H3K9me2 in the brains of AD patients. Likewise, treatment with a G9a inhibitor in SAMP8 mice reversed the high levels of H3K9me2 and rescued the cognitive decline. Interestingly, a transcriptional profile analysis revealed induction of neuronal plasticity and a reduction of oxidative stress and neuroinflammation; the latter being also validated in cell cultures. Furthermore, an exploratory H3K9me2 ChIP-seq analysis demonstrated that during G9a inhibition treatment, the H3K9me2 mark is enriched at the promoter of genes associated with neural functions. Lastly, we showed in Caenorhabditis elegans (C. elegans) AD transgenic strains, similar epigenetic modifications and modulated pathways were altered with increased β-amyloid levels, which were reverted by the set-25 (in C. elegans is similar to the mammalian G9a protein) knockout, including the cognitive impairment. Therefore, our findings confirm that RNAi suppression of set-25 or pharmacological G9a inhibition promotes a positive outcome in AD, being a promising therapeutic strategy.

2011 ◽  
Vol 44 (06) ◽  
Author(s):  
K Lerche ◽  
M Willem ◽  
K Kleinknecht ◽  
C Romberg ◽  
U Konietzko ◽  
...  

2020 ◽  
Vol 3 (2) ◽  
pp. 216-242 ◽  
Author(s):  
Mayuri Shukla ◽  
Areechun Sotthibundhu ◽  
Piyarat Govitrapong

The revelation of adult brain exhibiting neurogenesis has established that the brain possesses great plasticity and that neurons could be spawned in the neurogenic zones where hippocampal adult neurogenesis attributes to learning and memory processes. With strong implications in brain functional homeostasis, aging and cognition, various aspects of adult neurogenesis reveal exuberant mechanistic associations thereby further aiding in facilitating the therapeutic approaches regarding the development of neurodegenerative processes in Alzheimer’s Disease (AD). Impaired neurogenesis has been significantly evident in AD with compromised hippocampal function and cognitive deficits. Melatonin the pineal indolamine augments neurogenesis and has been linked to AD development as its levels are compromised with disease progression. Here, in this review, we discuss and appraise the mechanisms via which melatonin regulates neurogenesis in pathophysiological conditions which would unravel the molecular basis in such conditions and its role in endogenous brain repair. Also, its components as key regulators of neural stem and progenitor cell proliferation and differentiation in the embryonic and adult brain would aid in accentuating the therapeutic implications of this indoleamine in line of prevention and treatment of AD.   


2020 ◽  
Vol 37 (2) ◽  
pp. 1-12
Author(s):  
Sara M. Kamal ◽  
Aliaa R.H. Mostafa ◽  
Sanaa M.R. Wahba

2020 ◽  
Vol 21 (12) ◽  
pp. 1164-1173
Author(s):  
Siju Ellickal Narayanan ◽  
Nikhila Sekhar ◽  
Rajalakshmi Ganesan Rajamma ◽  
Akash Marathakam ◽  
Abdullah Al Mamun ◽  
...  

: Alzheimer’s disease (AD) is a progressive brain disorder and one of the most common causes of dementia and death. AD can be of two types; early-onset and late-onset, where late-onset AD occurs sporadically while early-onset AD results from a mutation in any of the three genes that include amyloid precursor protein (APP), presenilin 1 (PSEN 1) and presenilin 2 (PSEN 2). Biologically, AD is defined by the presence of the distinct neuropathological profile that consists of the extracellular β-amyloid (Aβ) deposition in the form of diffuse neuritic plaques, intraneuronal neurofibrillary tangles (NFTs) and neuropil threads; in dystrophic neuritis, consisting of aggregated hyperphosphorylated tau protein. Elevated levels of (Aβ), total tau (t-tau) and phosphorylated tau (ptau) in cerebrospinal fluid (CSF) have become an important biomarker for the identification of this neurodegenerative disease. The aggregation of Aβ peptide derived from amyloid precursor protein initiates a series of events that involve inflammation, tau hyperphosphorylation and its deposition, in addition to synaptic dysfunction and neurodegeneration, ultimately resulting in dementia. The current review focuses on the role of proteomes in the pathogenesis of AD.


2018 ◽  
Vol 15 (13) ◽  
pp. 1191-1212 ◽  
Author(s):  
Botond Penke ◽  
Gábor Paragi ◽  
János Gera ◽  
Róbert Berkecz ◽  
Zsolt Kovács ◽  
...  

Lipids participate in Amyloid Precursor Protein (APP) trafficking and processing - important factors in the initiation of Alzheimer’s disease (AD) pathogenesis and influence the formation of neurotoxic β-amyloid (Aβ) peptides. An important risk factor, the presence of ApoE4 protein in AD brain cells binds the lipids to AD. In addition, lipid signaling pathways have a crucial role in the cellular homeostasis and depend on specific protein-lipid interactions. The current review focuses on pathological alterations of membrane lipids (cholesterol, glycerophospholipids, sphingolipids) and lipid metabolism in AD and provides insight in the current understanding of biological membranes, their lipid structures and functions, as well as their role as potential therapeutic targets. Novel methods for studying the membrane structure and lipid composition will be reviewed in a broad sense whereas the use of lipid biomarkers for early diagnosis of AD will be shortly summarized. Interactions of Aβ peptides with the cell membrane and different subcellular organelles are reviewed. Next, the details of the most important lipid signaling pathways, including the role of the plasma membrane as stress sensor and its therapeutic applications are given. 4-hydroxy-2-nonenal may play a special role in the initiation of the pathogenesis of AD and thus the “calpain-cathepsin hypothesis” of AD is highlighted. Finally, the most important lipid dietary factors and their possible use and efficacy in the prevention of AD are discussed.


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