| 1. |
- Bergström, Petra, et al.
(author)
-
Amyloid precursor protein expression and processing are differentially regulated during cortical neuron differentiation
- 2016
-
In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
-
Journal article (peer-reviewed)abstract
- Amyloid precursor protein (APP) and its cleavage product amyloid beta (A beta) have been thoroughly studied in Alzheimer's disease. However, APP also appears to be important for neuronal development. Differentiation of induced pluripotent stem cells (iPSCs) towards cortical neurons enables in vitro mechanistic studies on human neuronal development. Here, we investigated expression and proteolytic processing of APP during differentiation of human iPSCs towards cortical neurons over a 100-day period. APP expression remained stable during neuronal differentiation, whereas APP processing changed. alpha-Cleaved soluble APP (sAPP alpha) was secreted early during differentiation, from neuronal progenitors, while beta-cleaved soluble APP (sAPP beta) was first secreted after deep-layer neurons had formed. Short A beta peptides, including A beta 1-15/16, peaked during the progenitor stage, while processing shifted towards longer peptides, such as A beta 1-40/42, when post-mitotic neurons appeared. This indicates that APP processing is regulated throughout differentiation of cortical neurons and that amyloidogenic APP processing, as reflected by A beta 1-40/42, is associated with mature neuronal phenotypes.
|
|
| 2. |
- Portelius, Erik, 1977, et al.
(author)
-
Distinct cerebrospinal fluid amyloid beta peptide signatures in sporadic and PSEN1 A431E-associated familial Alzheimer's disease.
- 2010
-
In: Molecular neurodegeneration. - : Springer Science and Business Media LLC. - 1750-1326. ; 5:2
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Alzheimer's disease (AD) is associated with deposition of amyloid beta (Abeta) in the brain, which is reflected by low concentration of the Abeta1-42 peptide in the cerebrospinal fluid (CSF). There are at least 15 additional Abeta peptides in human CSF and their relative abundance pattern is thought to reflect the production and degradation of Abeta. Here, we test the hypothesis that AD is characterized by a specific CSF Abeta isoform pattern that is distinct when comparing sporadic AD (SAD) and familial AD (FAD) due to different mechanisms underlying brain amyloid pathology in the two disease groups. RESULTS: We measured Abeta isoform concentrations in CSF from 18 patients with SAD, 7 carriers of the FAD-associated presenilin 1 (PSEN1) A431E mutation, 17 healthy controls and 6 patients with depression using immunoprecipitation-mass spectrometry. Low CSF levels of Abeta1-42 and high levels of Abeta1-16 distinguished SAD patients and FAD mutation carriers from healthy controls and depressed patients. SAD and FAD were characterized by similar changes in Abeta1-42 and Abeta1-16, but FAD mutation carriers exhibited very low levels of Abeta1-37, Abeta1-38 and Abeta1-39. CONCLUSION: SAD patients and PSEN1 A431E mutation carriers are characterized by aberrant CSF Abeta isoform patterns that hold clinically relevant diagnostic information. PSEN1 A431E mutation carriers exhibit low levels of Abeta1-37, Abeta1-38 and Abeta1-39; fragments that are normally produced by gamma-secretase, suggesting that the PSEN1 A431E mutation modulates gamma-secretase cleavage site preference in a disease-promoting manner.
|
|
| 3. |
- Wasling, Pontus, et al.
(author)
-
Synaptic retrogenesis and amyloid-beta in Alzheimer's disease.
- 2009
-
In: Journal of Alzheimer's disease : JAD. - 1387-2877. ; 16:1, s. 1-14
-
Research review (peer-reviewed)abstract
- Pathological hallmarks of Alzheimer's disease (AD) include synaptic and neuronal degeneration and the presence of extracellular deposits of amyloid-beta (Abeta) in senile plaques in the cerebral cortex. Although these brain lesions may be seen also in aged non-demented individuals, the increase in brain Abeta is believed by many to represent the earliest event in the disease process. Accumulating evidence suggests that Abeta, which is highly conserved by evolution, may have an important physiological role in synapse elimination during brain development. An intriguing idea is that this putative function can become pathogenic if activated in the aging brain. Here, we review the literature on the possible physiological roles of Abeta and its precursor protein AbetaPP during development with special focus on electrophysiological findings.
|
|
