Abstract
Recombinant adenoviruses were used for the expression of human amyloid precursor protein (APP) of Alzheimer's disease in primary cultures of rat cortical neurons and astrocytes. The catabolic pathways of human APP were studied 3 to 4 days after infection, when the equilibrium of APP production was reached. Although the expression of human wild type APP (WtAPP) by rat neurons induced the production of both extracellular and intraneuronal amyloid peptide (Abeta), Abeta was not detected in the culture medium of rat astrocytes producing human WtAPP. Because a low beta-secretase activity was previously reported in rodent astrocytes, we wondered whether modifications of the APP amino acid sequence at the beta-secretase clipping site would modify the astrocytic production of Abeta. Interestingly, rat astrocytes produced high amounts of Abeta after expression of human APP carrying a double amino acid substitution responsible for Alzheimer's disease in a large Swedish family (SwAPP). In both rat cortical neurons and astrocytes, the beta-secretase cleavage of the human SwAPP occurred very early in the secretion process in a cellular compartment in which a different sorting of SwAPP and WtAPP seems unlikely. These results suggest that human WtAPP and SwAPP could be processed by different beta-secretase activities.
Highlights
Alzheimer’s disease is the most common form of dementia
We found that human wild type amyloid precursor protein (APP) (WtAPP) is processed in a distinct manner in rat cortical neurons and astrocytes
To compare in details the relative efficiency of infection by this vector, rat cortical neurons and astrocytes were infected by a recombinant adenovirus carrying the LacZ gene (AdRSV-gal) at different multiplicities of infection, and the -galactosidase activity was revealed by histochemistry
Summary
A, amyloid peptide; APP, amyloid precursor protein; SFV, Semliki Forest virus; WtAPP, wild type APP; SwAPP, Swedish family APP; Ad, adenovirus; RSV, Rous sarcoma virus; TBS, Tris-buffered saline. This non-amyloidogenic pathway, which precludes the formation of full-length A, occurs during the processing of APP to the plasma membrane as early as in the trans-Golgi network [6, 7] This cleavage releases the N-terminal ectodomain of APP containing the first 17 amino acids of A into the culture medium of transfected cells. We have constructed recombinant adenoviruses that allow the long term expression of human APP into primary cultures of rat cortical neurons and astrocytes without cytopathic effect. Astrocytes produce high amounts of A from human APP carrying a double amino acid substitution responsible for Alzheimer’s disease in a Swedish family (SwAPP) In both neurons and astrocytes, the -cleavage of SwAPP occurs early in the secretion process. This suggests that WtAPP and SwAPP could be processed by different -secretase activities
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
