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Muscarinic M1 receptor agonists increase the secretion of the amyloid precursor protein ectodomain
D M Müller1, K Mendla, S A Farber
1Center for Molecular Neurobiology, University of Hamburg, Germany.
Abstract:
Amyloid deposits in Alzheimer's disease are composed of amyloid beta-peptides (A beta) that are derived from the larger amyloid precursor protein (APP). Proteolytic APP processing is activity-dependent, and it can be regulated by muscarinic acetylcholine receptors. In particular, muscarinic m1 receptor subtypes increase cleavage within the A beta domain, followed by the release of the soluble APP ectodomain (APPs). In this study, we show that the m1-selective agonist talsaclidine concentration-dependently increased APPs release from both transfected human astrocytoma cell lines and rat brain slices. This increase was blocked by atropine. In contrast, the M2 antagonist BIBN 99 failed to increase APPs release, and decreased it at higher concentrations. These results show that talsaclidine can effectively modulate alpha-secretase processing of APP in human cell lines and in brain tissue. The data suggest that talsaclidine may be a useful candidate drug to modulate APP processing in Alzheimer's disease.
Insights
Talsaclidine, a muscarinic m1 receptor agonist, effectively increases soluble amyloid precursor protein (APP) release in cell lines and brain tissue. This suggests talsaclidine
Area of Science:
- Neuroscience
- Molecular Biology
- Pharmacology
Background:
- Alzheimer's disease (AD) involves amyloid-beta peptide (A beta) deposits, derived from amyloid precursor protein (APP).
- APP processing is regulated by muscarinic acetylcholine receptors, particularly m1 subtypes, which influence alpha-secretase cleavage.
- Modulating APP processing is a therapeutic strategy for AD.
Purpose of the Study:
- To investigate the effect of the m1-selective agonist talsaclidine on APP processing.
- To determine if talsaclidine modulates alpha-secretase activity in vitro and in brain tissue.
Main Methods:
- Utilized transfected human astrocytoma cell lines and rat brain slices.
- Administered talsaclidine and measured the release of soluble APP ectodomain (APPs).
- Investigated the role of muscarinic receptor subtypes using specific agonists and antagonists (atropine, BIBN 99).
Main Results:
- Talsaclidine demonstrated a concentration-dependent increase in APPs release.
- This effect was blocked by atropine, confirming muscarinic receptor involvement.
- The M2 antagonist BIBN 99 did not increase, and decreased APPs release at higher concentrations.
Conclusions:
- Talsaclidine effectively modulates alpha-secretase processing of APP in human cell lines and rat brain tissue.
- The findings support the potential of talsaclidine as a therapeutic agent for Alzheimer's disease by influencing APP metabolism.