Dataset Information

Rapamycin ameliorates cognitive impairment by activating microglial amyloid-β degradation in mouse models of amyloidosis

ABSTRACT: Alzheimer's disease (AD) lacks effective treatments despite being the most prevalent dementia. This study examines whether rapamycin, an mTOR inhibitor with immunomodulatory properties, alleviates AD pathology by regulating microglia (the brain's resident immune cells).Rapamycin was administered orally to 2-month-old 5×FAD and hAPPNL-G-F mice, two amyloid plaque-dominant AD models. Behavioral and AD-pathological assessments were performed at approximately 5 months of age. Primary microglia exposed to rapamycin and fluorescently labeled amyloid-β (Aβ) oligomers were analyzed for phagocytic and degradative functions. The BV2 microglial cell line received rapamycin, oleic acid, and autophagy inhibitors to investigate mechanisms underlying rapamycin-regulated microglial degradation capacity. Oral rapamycin administration significantly reduced cerebral Aβ plaque burden, diminished dystrophic neurites, suppressed glial hyperactivation, and increased plaque-proximal microglial density in both 5×FAD and hAPPNL-G-F mice, ultimately mitigating memory deficits. Mechanistic investigations revealed rapamycin-activated microglial lysosomal degradation pathways, stimulated lipid droplet clearance in BV2 microglia, and enhanced Aβ phagocytic clearance in primary microglia. Our findings provide compelling evidence that rapamycin enhances Aβ clearance by targeting microglial lysosomal function, thereby establishing a novel glia-directed therapeutic strategy for AD.

ORGANISM(S): Mus musculus

PROVIDER: GSE304662 | GEO | 2026/03/04

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

Items per page:

1 - 5 of 6

Similar Datasets

Project description:Neuroinflammation is thought to contribute to the pathogenesis of Alzheimer’s disease (AD), yet numerous studies have demonstrated a beneficial role for neuroinflammation in amyloid plaque clearance. We have previously shown that sustained expression of IL-1β in the hippocampus of APP/PS1 mice decreases amyloid plaque burden independent of recruited CCR2+ myeloid cells, suggesting resident microglia as the main phagocytic effectors of IL-1β-induced plaque clearance. To date, however, the mechanisms of IL-1β-induced plaque clearance remain poorly understood. To determine whether IL-1β-induced plaque clearance is due to enhanced microglial phagocytosis of Aβ, APP/PS1 mice induced to express mature human IL-1β in the hippocampus via adenoviral transduction were treated with the Aβ fluorescent probe methoxy-X04 (MX04) and microglial internalization of Aβ was analyzed by flow cytometry and immunohistochemistry. We found that resident microglia (CD45loCD11b+) constituted >70% of the MX04+ cells in both control and IL-1β-treated conditions, and that <10% of MX04+ cells were recruited myeloid cells (CD45hiCD11b+). However, we found that IL-1β treatment did not augment the percentage of MX04+ microglia nor the quantity of Aβ internalized by individual microglia. Instead, we found that IL-1β treatment resulted in a significant increase in the total number of MX04+ microglia in the hippocampus due to IL-1β-induced proliferation. Consistent with these results, transcriptomic analyses revealed very similar gene expression profiles between MX04+ and MX04- microglia, indicating IL-1β does not drive enhanced expression of phagocytosis-related genes. By contrast, IL-1β treatment was associated with large-scale changes in the expression of genes related to proliferation, immune function and inflammation. Together, these studies demonstrate that IL-1β induces microglial proliferation and the expression of genes involved in inflammatory immune functions that may be related to Aβ clearance.

Project description:Microglia are innate immune cells of the brain that perform phagocytic and inflammatory functions in disease conditions. Transcriptomic studies of acutely-isolated microglia have provided novel insights into their molecular and functional diversity in homeostatic and neurodegenerative disease states. State-of-the-art mass spectrometric methods can comprehensively characterize proteomic alterations in microglia in neurodegenerative disorders, potentially providing novel functionally-relevant molecular insights that are not provided by transcriptomics. However, proteomic profiling of adult primary microglia in neurodegenerative disease conditions has not been performed. We performed quantitative proteomic analyses of purified CD11b+ acutely-isolated microglia adult mice in normal, acute neuroinflammatory (LPS-treatment) and chronic neurodegenerative states (5xFAD model of Alzheimer’s disease [AD]) using tandem mass tag mass spectrometry. Differential expression analyses were performed to characterize specific microglial proteomic changes in 5xFAD mice and identify overlap with LPS-induced pro-inflammatory changes. Our results were also contrasted with existing proteomic data from wild-type mouse microglia and from existing microglial transcriptomic data from wild-type and 5xFAD mice. Neuropathological validation studies of select proteins were performed in human AD and 5xFAD brains. Of 4,133 proteins identified, 187 microglial proteins were differentially expressed in the 5xFAD mouse model of AD pathology, including proteins with previously known (Apoe, Clu and Htra1) as well as previously unreported relevance to AD biology (Cotl1 and Hexb). Proteins upregulated in 5xFAD microglia shared significant overlap with pro-inflammatory changes observed in LPS-treated mice. Several proteins increased in human AD brain were also upregulated by 5xFAD microglia (Aβ peptide, Apoe, Htra1, Cotl1 and Clu). Cotl1 was identified as a novel microglia-specific marker with increased expression and strong association with AD neuropathology. Apoe protein was also detected within plaque-associated microglia in which Apoe and Aβ were highly co-localized suggesting a role for Apoe in phagocytic clearance of Aβ. We report the first comprehensive comparative proteomic study of adult mouse microglia derived from acute neuroinflammatory and AD models, representing a valuable resource to the neuroscience research community. We highlight shared and unique microglial proteomic changes in acute neuroinflammatory, aging and AD mouse models in addition to identifying novel roles for microglial proteins in human neurodegeneration.

			Action	DRS
		Other
	GSE304662_FC.txt.gz	Txt
	GSE304662_FR.txt.gz	Txt
	GSE304662_MC.txt.gz	Txt
	GSE304662_MR.txt.gz	Txt

Dataset Information

Rapamycin ameliorates cognitive impairment by activating microglial amyloid-β degradation in mouse models of amyloidosis

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets