Early Locus Coeruleus noradrenergic axon loss drives olfactory dysfunction in Alzheimer’s disease
Year: 2025
Type: article
Abstract: Alzheimer’s disease (AD) often begins with non-cognitive symptoms such as olfactory deficits, which can predict later cognitive decline, though the mechanisms remain unclear. Pathologically, the brainstem locus coeruleus (LC), the main source of the neurotransmitter noradrenalin (NA) modulating olfactory information processing is affected early. Here we show early and distinct loss of noradrenergic input to the olfactory bulb (OB) coinciding with impaired olfaction in an AD mouse model, before appearance of amyloid plaques. Mechanistically, OB microglia recognize and phagocytose LC axons. Reducing phagocytosis genetically preserves LC axons and olfaction. Prodromal AD patients display elevated TSPO-PET signals in the OB, similarly to App NL-G-F mice. We further confirm early LC axon degeneration in post-mortem OBs in patients with early AD. Our findings reveal a mechanism linking early LC damage to hyposmia in AD, suggesting olfactory testing and neurocircuit imaging for early diagnosis and enable timely therapeutic intervention for Alzheimer’s disease.
Source: Nature Communications
Authors: Carolin Meyer, Theresa Niedermeier, Paul L. C. Feyen, Felix L. Strübing, Boris-Stephan Rauchmann, Katerina Karali, Johanna Gentz, Yannik E. Tillmann, Nicolas F. Landgraf, Svenja-Lotta Rumpf, Katharina Ochs, Karin Wind-Mark, Gloria Biechele, Jessica Wagner, Selim Guersel, Carolin I. Kurz, Meike Schweiger, Danilo Prtvar, Yuan Shi, Richard B. Banati, Guo-Jun Liu, Ryan J. Middleton, Gerda Mitteregger-Kretzschmar, Robert Perneczky, Thomas Koeglsperger, Jonas J. Neher, Sabina Tahirovic, Matthias Brendel, Jochen Herms, Lars Paeger
Institutions: German Center for Neurodegenerative Diseases, Institut für Neuropathologie, Ludwig-Maximilians-Universität München, LMU Klinikum, Institut für Diagnostische und Interventionelle Neuroradiologie, Munich Cluster for Systems Neurology, The University of Sydney, Australian Nuclear Science and Technology Organisation, Imperial College London, University of Sheffield, Deutsches Konsortium für Translationale Krebsforschung
Language: English
Subfield: Sensory Systems
Field: Neuroscience
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $6,990
Awards: G1789099517, G2060262474, G2524323436, G2588154941, FOR 2858: Bedeutung des Translokator Proteins (18kDa) (TSPO) als diagnostische und therapeutische Zielstruktur im Nervensystem, PREDICTION OF ALZHEIMER’S DISEASE USING AN AI DRIVEN SCREENING PLATFORM, EXC 2145: Munich Cluster for Systems Neurology (SyNergy), G645767916
OpenAlex ID: W4413055652