scholarly journals Amyloid precursor protein (APP) knock‐in mouse model recapitulates transciptomic signature in human late‐onset Alzheimer’s disease

2020 ◽  
Vol 16 (S2) ◽  
Author(s):  
Marco Antônio De Bastiani ◽  
Eduardo R. Zimmer ◽  
Stefania Forner ◽  
Alessandra Cadete Martini
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.


2020 ◽  
pp. 1-16
Author(s):  
Margaret Ryan ◽  
Valerie T.Y. Tan ◽  
Nasya Thompson ◽  
Diane Guévremont ◽  
Bruce G. Mockett ◽  
...  

Background: Secreted amyloid precursor protein-alpha (sAPPα) can enhance memory and is neurotrophic and neuroprotective across a range of disease-associated insults, including amyloid-β toxicity. In a significant step toward validating sAPPα as a therapeutic for Alzheimer’s disease (AD), we demonstrated that long-term overexpression of human sAPPα (for 8 months) in a mouse model of amyloidosis (APP/PS1) could prevent the behavioral and electrophysiological deficits that develop in these mice. Objective: To explore the underlying molecular mechanisms responsible for the significant physiological and behavioral improvements observed in sAPPα-treated APP/PS1 mice. Methods: We assessed the long-term effects on the hippocampal transcriptome following continuous lentiviral delivery of sAPPα or empty-vector to male APP/PS1 mice and wild-type controls using Affymetrix Mouse Transcriptome Assays. Data analysis was carried out within the Affymetrix Transcriptome Analysis Console and an integrated analysis of the resulting transcriptomic data was performed with Ingenuity Pathway analysis (IPA). Results: Mouse transcriptome assays revealed expected AD-associated gene expression changes in empty-vector APP/PS1 mice, providing validation of the assays used for the analysis. By contrast, there were specific sAPPα-associated gene expression profiles which included increases in key neuroprotective genes such as Decorin, betaine-GABA transporter, and protocadherin beta-5, subsequently validated by qRT-PCR. An integrated biological pathways analysis highlighted regulation of GABA receptor signaling, cell survival, and inflammatory responses. Furthermore, upstream gene regulatory analysis implicated sAPPα activation of Interleukin-4, which can counteract inflammatory changes in AD. Conclusion: This study identified key molecular processes that likely underpin the long-term neuroprotective and therapeutic effects of increasing sAPPα levels in vivo


Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1275
Author(s):  
Soo Yong Park ◽  
Joo Yeong Kang ◽  
Taehee Lee ◽  
Donggyu Nam ◽  
Chang-Jin Jeon ◽  
...  

Alzheimer’s disease (AD) is a complex, age-related neurodegenerative disease that is the most common form of dementia. However, the cure for AD has not yet been founded. The accumulation of amyloid beta (Aβ) is considered to be a hallmark of AD. Beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), also known as beta secretase is the initiating enzyme in the amyloidogenic pathway. Blocking BACE1 could reduce the amount of Aβ, but this would also prohibit the other functions of BACE1 in brain physiological activity. SPONDIN1 (SPON1) is known to bind to the BACE1 binding site of the amyloid precursor protein (APP) and blocks the initiating amyloidogenesis. Here, we show the effect of SPON1 in Aβ reduction in vitro in neural cells and in an in vivo AD mouse model. We engineered mouse induced neural stem cells (iNSCs) to express Spon1. iNSCs harboring mouse Spon1 secreted SPON1 protein and reduced the quantity of Aβ when co-cultured with Aβ-secreting Neuro 2a cells. The human SPON1 gene itself also reduced Aβ in HEK 293T cells expressing the human APP transgene with AD-linked mutations through lentiviral-mediated delivery. We also demonstrated that injecting SPON1 reduced the amount of Aβ and ameliorated cognitive dysfunction and memory impairment in 5xFAD mice expressing human APP and PSEN1 transgenes with five AD-linked mutations.


2021 ◽  
Author(s):  
Shane M. Ohline ◽  
Connie Chan ◽  
Lucia Schoderboeck ◽  
Hollie E. Wicky ◽  
Warren P. Tate ◽  
...  

Abstract Soluble amyloid precursor protein-alpha (sAPPα) is a regulator of neuronal and memory mechanisms, while also having neurogenic and neuroprotective effects in the brain. As adult hippocampal neurogenesis is impaired in Alzheimer’s disease, we tested the hypothesis that sAPPα delivery would rescue adult hippocampal neurogenesis in an APP/PS1 mouse model of Alzheimer’s disease. An adeno-associated virus-9 (AAV9) encoding murine sAPPα was injected into the hippocampus of 8 month-old wild-type and APP/PS1 mice, and later two different thymidine analogues (XdU) were systemically injected to label adult-born cells at different time points after viral transduction. The proliferation of adult-born cells, cell survival after eight weeks, and cell differentiation into either neurons or astrocytes was studied. Proliferation was impaired in APP/PS1 mice but was restored to wild-type levels by viral expression of sAPPα. In contrast, sAPPα overexpression failed to rescue the survival of XdU+-labelled cells that was impaired in APP/PS1 mice, although it did cause a significant increase in the area density of astrocytes in the granule cell layer across both genotypes. Finally, viral expression of sAPPα reduced amyloid-beta plaque load in APP/PS1 mice in the dentate gyrus and somatosensory cortex. These data add further evidence that increased levels of sAPPα could be therapeutic for the cognitive decline in AD, in part through restoration of the proliferation of neural progenitor cells in adults.


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