scholarly journals Intracellular Calcium Dysregulation by the Alzheimer’s Disease-Linked Protein Presenilin 2

2020 ◽  
Vol 21 (3) ◽  
pp. 770 ◽  
Author(s):  
Luisa Galla ◽  
Nelly Redolfi ◽  
Tullio Pozzan ◽  
Paola Pizzo ◽  
Elisa Greotti

Alzheimer’s disease (AD) is the most common form of dementia. Even though most AD cases are sporadic, a small percentage is familial due to autosomal dominant mutations in amyloid precursor protein (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2) genes. AD mutations contribute to the generation of toxic amyloid β (Aβ) peptides and the formation of cerebral plaques, leading to the formulation of the amyloid cascade hypothesis for AD pathogenesis. Many drugs have been developed to inhibit this pathway but all these approaches currently failed, raising the need to find additional pathogenic mechanisms. Alterations in cellular calcium (Ca2+) signaling have also been reported as causative of neurodegeneration. Interestingly, Aβ peptides, mutated presenilin-1 (PS1), and presenilin-2 (PS2) variously lead to modifications in Ca2+ homeostasis. In this contribution, we focus on PS2, summarizing how AD-linked PS2 mutants alter multiple Ca2+ pathways and the functional consequences of this Ca2+ dysregulation in AD pathogenesis.

2014 ◽  
Vol 56 ◽  
pp. 99-110 ◽  
Author(s):  
David Allsop ◽  
Jennifer Mayes

One of the hallmarks of AD (Alzheimer's disease) is the formation of senile plaques in the brain, which contain fibrils composed of Aβ (amyloid β-peptide). According to the ‘amyloid cascade’ hypothesis, the aggregation of Aβ initiates a sequence of events leading to the formation of neurofibrillary tangles, neurodegeneration, and on to the main symptom of dementia. However, emphasis has now shifted away from fibrillar forms of Aβ and towards smaller and more soluble ‘oligomers’ as the main culprit in AD. The present chapter commences with a brief introduction to the disease and its current treatment, and then focuses on the formation of Aβ from the APP (amyloid precursor protein), the genetics of early-onset AD, which has provided strong support for the amyloid cascade hypothesis, and then on the development of new drugs aimed at reducing the load of cerebral Aβ, which is still the main hope for providing a more effective treatment for AD in the future.


2015 ◽  
Vol 17 (26) ◽  
pp. 16886-16893 ◽  
Author(s):  
Xu Wang ◽  
Xianqiang Sun ◽  
Guanglin Kuang ◽  
Hans Ågren ◽  
Yaoquan Tu

The investigation of the (ZAβ3)2:Aβ complex highlights the energetic contribution of affibody residues to the binding with alzheimer's disease associated Aβ peptides.


2021 ◽  
Author(s):  
Rolando Oyola ◽  
Deguo Du ◽  
Idalia Ramos ◽  
Kyabeth Torres ◽  
Ambar S Delgado ◽  
...  

Alzheimer’s disease (AD) has been consistently related to the formation of senile amyloid plaques mainly composed of amyloid β (Aβ) peptides. The toxicity of Aβ aggregates has been indicated to...


Author(s):  
Prativa Sadhu ◽  
◽  
Srijani Sen ◽  
Catherine Vanlalhriatpuii ◽  
◽  
...  

Neurodegenerative disorders are marked by the loss of brain neuron activity, resulting in gradual cognitive impairment. The effects of neurodegenerative diseases are severe in terms of pathology and the cost of patient care. The aged, in general, are the most vulnerable. Alzheimer's disease (AD) is a brain ailment that causes cell degradation and is the leading cause of dementia, identified by a loss of thinking ability and independence in daily tasks. The amyloid cascade hypothesis, which attributes clinical signs/symptoms to an abundance of amyloid-beta (Aβ) peptides, enhanced deposition into amyloid plaques, and eventually neuronal destruction, is one theory for pathogenesis AD. The use of acetylcholinesterase inhibitors in AD treatment is based on their favorable effects on the disease's functional, cognitive and behavioral symptoms. However, their involvement in AD pathogenesis is uncertain. This comprehensive review will provide an overview of AD, including the pathophysiology, causes, treatments, and future treatment.


Author(s):  
Qi Wu ◽  
Leonardo Cortez ◽  
Razieh Kamali-Jamil ◽  
Valerie Sim ◽  
Holger Wille ◽  
...  

Amyloid β (Aβ) peptides generated from the amyloid precursor protein (APP) play a critical role in the development of Alzheimer's disease (AD) pathology. Aβ-containing neuronal exosomes, which represent a novel form of intercellular communication, have been shown to influence function/vulnerability of neurons in AD. Unlike neurons, the significance of exosomes derived from astrocytes remains unclear. In this study, we evaluated the significance of exosomes derived from U18666A-induced cholesterol-accumulated astrocytes in the development of AD pathology. Our results show that cholesterol accumulation decreases exosome secretion, whereas lowering cholesterol level increases exosome secretion from cultured astrocytes. Interestingly, exosomes secreted from U18666A-treated astrocytes contain higher levels of APP, APP-CTFs, soluble APP, APP secretases and Aβ1-40 than exosomes secreted from control astrocytes. Furthermore, we show that exosomes derived from U18666A-treated astrocytes can lead to neurodegeneration, which is attenuated by decreasing Aβ production or by neutralizing exosomal Aβ peptide with an Aβ antibody. These results, taken together, suggest that exosomes derived from cholesterol-accumulated astrocytes can play an important role in trafficking APP/Aβ peptides and influencing neuronal viability in the affected regions of the AD brain.


2020 ◽  
Vol 10 (2) ◽  
pp. 122 ◽  
Author(s):  
Bor Luen Tang

Amyloid β (Aβ) peptides generated via sequential β- and γ-secretase processing of the amyloid precursor protein (APP) are major etiopathological agents of Alzheimer’s disease (AD). However, an initial APP cleavage by an α-secretase, such as the a disintegrin and metalloproteinase domain-containing protein ADAM10, precludes β-secretase cleavage and leads to APP processing that does not produce Aβ. The latter appears to underlie the disease symptom-attenuating effects of a multitude of experimental therapeutics in AD animal models. Recent work has indicated that an endogenous inhibitor of ADAM10, secreted-frizzled-related protein 1 (SFRP1), is elevated in human AD brains and associated with amyloid plaques in mouse AD models. Importantly, genetic or functional attenuation of SFRP1 lowered Aβ accumulation and improved AD-related histopathological and neurological traits. Given SFRP1′s well-known activity in attenuating Wnt signaling, which is also commonly impaired in AD, SFRP1 appears to be a promising therapeutic target for AD. This idea, however, needs to be addressed with care because of cancer enhancement potentials resulting from a systemic loss of SFRP1 activity, as well as an upregulation of ADAM10 activity. In this focused review, I shall discuss α-secretase-effected APP processing in AD with a focus on SFRP1, and explore the contrasting perspectives arising from the recent findings.


2008 ◽  
Vol 14 (3-4) ◽  
pp. 184-194 ◽  
Author(s):  
Gregory D. Van Vickle ◽  
Chera L. Esh ◽  
Tyler A. Kokjohn ◽  
R. Lyle Patton ◽  
Walter M. Kalback ◽  
...  

2010 ◽  
Vol 5 (1) ◽  
pp. 12
Author(s):  
Daniela Galimberti ◽  
Chiara Fenoglio ◽  
Elio Scarpini ◽  
◽  
◽  
...  

Alzheimer's disease (AD) is the most common cause of dementia in the elderly, whereas frontotemporal lobar degeneration (FTLD) is the most frequent neurodegenerative disorder with a pre-senile onset. The two major neuropathological hallmarks of AD are extracellular amyloid beta plaques and intracellular neurofibrillary tangles. In FTLD the deposition of tau has been observed in a number of cases, but in several brains there is no deposition of tau but instead a positivity for ubiquitin. In some families these diseases are inherited in an autosomal dominant fashion. Genes responsible for familial AD include the amyloid precursor protein (APP), presenilin 1 (PS1) and presenilin 2 (PS2), whereas the main genes responsible for familial FTLD are microtubule-associated protein tau gene (MAPT) and progranulin (GRN). Concerning sporadic AD, it is known that the presence of the ε4 allele of the apolipoprotein E gene is a susceptibility factor. A number of additional genetic factors contribute to susceptibility for AD and FTLD.


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