An Integrative Proteomic Approach to Reveal Altered Signaling Modules During Alzheimer's Disease Progression in PS19 Tauopathy Mice.

Alzheimer's disease (AD) is a slowly progressive neurodegenerative disease that is characterized by cognitive, functional, and behavioral impairments. These changes occur owing to the progressive accumulation of extracellular amyloid-beta plaques and intracellular neurofibrillary tangles of hyperphosphorylated tau protein. AD is associated with the dysfunction of several essential neurotransmitter systems, such as dopamine, and impaired neurotransmission. Despite the association of neurotransmitter changes within the brain and AD pathology, in-depth profiling studies on neurotransmitters and their related proteomic changes are limited. This study was conducted to profile and integrate the proteomes and neurotransmitters in seven brain regions of PS19 (Tau P301S) mice according to AD progression between 4 and 7 months. Proteomic analysis revealed significantly altered canonical pathways in various brain regions, including metabolic abnormalities. In the neurotransmitter profile, we found significant alterations in the levels of six neurotransmitters-dopamine, serotonin, homovanillic acid, norepinephrine, 3-methoxytyramine, and 3,4-dihydroxyphenylacetic acid-during AD progression. Using an integrative approach between proteome and neurotransmitter profiles, we found that AD progression-dependent dopamine- and serotonin-related signaling modules are closely related to neurotransmitter changes, especially in the hippocampus and cerebellum. This integrative approach could provide new signaling modules to help understand AD progression and thereby enable improved treatment and clinical outcomes.