Abstract
Alzheimers Res Ther. 2026 May 28. doi: 10.1186/s13195-026-02092-7. Online ahead of print.
ABSTRACT
The aim of this study is to assess the levels of meprin-β, an alternative β-secretase in the brain and cerebrospinal fluid of subjects suffering Alzheimer's disease. The full-length zymogen and the active species of meprin-β were characterized by immunoblotting and immunoprecipitation using ectodomain N-terminal and C-terminal antibodies. We examined meprin-β changes in extracts from Alzheimer's frontal cortex (n = 13, Braak stages I-II; n = 12, Braak stages III-IV; n = 12, Braak stages V-VI) compared with controls (n = 14), as well as in cerebrospinal fluid samples from Alzheimer's patients (n = 15) or non-Alzheimer's controls (n = 15). Cerebrospinal fluid meprin-β levels were also determined in 19-month old TgF344-AD and wild-type rats. Brain and cerebrospinal fluid from a Mep1b-null mouse served to characterize the specificity of the immunoreactive bands for meprin-β. Human induced pluripotent stem cell (iPSC)-derived neuronal cultures were treated with 2 μM Aβ42 for 24 h. We found that meprin-β is present in human brain extracts and cerebrospinal fluid as several distinct species, attributed to the zymogen and the mature species. These species were absent in brain and cerebrospinal fluid from a Mep1b-null mouse. No fragments of meprin-β were detected in brain extract, either in cerebrospinal fluid. Only the mature forms of meprin-β are increased in frontal cortex extracts (from Braak V-VI), but not the zymogen. The MEP1-B mRNA levels are increased in Braaks III-IV and V-VI compared with controls. The meprin-β species are increased in human neuronal cultures treated with Aβ42. Finally, we demonstrated elevated levels of the mature meprin-β in the cerebrospinal fluid of patients with Alzheimer's disease and in TgF344-AD rats. Our data support a role of meprin-β in Alzheimer's pathology.
PMID:42210401 | DOI:10.1186/s13195-026-02092-7
UK DRI Authors
