The emergence of Alzheimer's disease (AD) pathology has been the focus of multiple hypotheses, with amyloid β (Aβ) playing a central role due to its presence in both familial and sporadic AD. Therefor Show more
The emergence of Alzheimer's disease (AD) pathology has been the focus of multiple hypotheses, with amyloid β (Aβ) playing a central role due to its presence in both familial and sporadic AD. Therefore, a crucial aspect of AD research is understanding the generation of different Aβ species. Aβ peptides result from the proteolytic processing of Amyloid Precursor Protein (APP) by β- and γ-secretases, with BACE1 being the most prominent β-secretase. However, BACE1-overexpressing mouse models exhibit disadvantages, making them limited for AD research. Importantly, N-terminally truncated Aβ species, which constitute up to 70 % of Aβ in AD brains, are not generated by BACE1. In recent years, alternative proteases capable of cleaving APP have been identified, bridging the gap between N-terminally truncated Aβ species and BACE1-derived Aβ. Among these novel players, the metalloprotease meprin β has emerged as a risk factor in AD pathology, generating both N-terminally truncated and full-length Aβ species. Our primary objective was to develop a mouse model that more accurately resembles the pathology of AD beyond BACE1-overexpressing models, while simultaneously confirming APP cleavage of meprin β in the hippocampus and cerebral cortex. Overexpression of meprin β led to a marked increase in soluble Aβ levels, particularly in the hippocampus, indicating a higher vulnerability or elevated meprin β activity in this region compared to the cerebral cortex. Notably, this biochemical change occurred without any observable behavioral deficits, suggesting a region-specific role of meprin β in AD pathology that may extend beyond immediate functional impairment. Show less