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Aloi MS, Prater KE, Sánchez REA, Beck A, Pathan JL, Davidson S, Wilson A, Keene CD, de la Iglesia H, Jayadev S, Garden GA. Microglia specific deletion of miR-155 in Alzheimer's disease mouse models reduces amyloid-β pathology but causes hyperexcitability and seizures. J Neuroinflammation 2023; 20:60. [PMID: 36879321 PMCID: PMC9990295 DOI: 10.1186/s12974-023-02745-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 02/21/2023] [Indexed: 03/08/2023] Open
Abstract
Alzheimer's Disease (AD) is characterized by the accumulation of extracellular amyloid-β (Aβ) as well as CNS and systemic inflammation. Microglia, the myeloid cells resident in the CNS, use microRNAs to rapidly respond to inflammatory signals. MicroRNAs (miRNAs) modulate inflammatory responses in microglia, and miRNA profiles are altered in Alzheimer's disease (AD) patients. Expression of the pro-inflammatory miRNA, miR-155, is increased in the AD brain. However, the role of miR-155 in AD pathogenesis is not well-understood. We hypothesized that miR-155 participates in AD pathophysiology by regulating microglia internalization and degradation of Aβ. We used CX3CR1CreER/+ to drive-inducible, microglia-specific deletion of floxed miR-155 alleles in two AD mouse models. Microglia-specific inducible deletion of miR-155 in microglia increased anti-inflammatory gene expression while reducing insoluble Aβ1-42 and plaque area. Yet, microglia-specific miR-155 deletion led to early-onset hyperexcitability, recurring spontaneous seizures, and seizure-related mortality. The mechanism behind hyperexcitability involved microglia-mediated synaptic pruning as miR-155 deletion altered microglia internalization of synaptic material. These data identify miR-155 as a novel modulator of microglia Aβ internalization and synaptic pruning, influencing synaptic homeostasis in the setting of AD pathology.
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Affiliation(s)
- Macarena S Aloi
- Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA, 98195, USA
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Katherine E Prater
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | | | - Asad Beck
- Department of Biology, University of Washington, Seattle, WA, 98109, USA
| | - Jasmine L Pathan
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Stephanie Davidson
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Angela Wilson
- Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA, 98195, USA
| | - C Dirk Keene
- Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA, 98195, USA
| | | | - Suman Jayadev
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Gwenn A Garden
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, 98195, USA.
- Department of Neurology, University of North Carolina at Chapel Hill, 170 Manning Drive, Chapel Hill, NC, 27517, USA.
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