Priming of microglia with IFN-γ slows neuronal gamma oscillations in situ

• Verfasst von: Ta, Thuy-Truc [VerfasserIn]
• Verfasst von: Dikmen, Hasan Onur [VerfasserIn]
• Verfasst von: Chausse de Freitas, Bruno [VerfasserIn]
• Verfasst von: Lewen, Andrea [VerfasserIn]
• Verfasst von: Hollnagel, Jan-Oliver [VerfasserIn]
• Verfasst von: Kann, Oliver [VerfasserIn]
• Titel: Priming of microglia with IFN-γ slows neuronal gamma oscillations in situ
• Verf.angabe: Thuy-Truc Ta, Hasan Onur Dikmen, Simone Schilling, Bruno Chausse, Andrea Lewen, Jan-Oliver Hollnagel, and Oliver Kann
• E-Jahr: 2019
• Jahr: February 19, 2019
• Umfang: 6 S.
• Fussnoten: Gesehen am 29.05.2019
• Titel Quelle: Enthalten in: National Academy of Sciences (Washington, DC)Proceedings of the National Academy of Sciences of the United States of America
• Ort Quelle: Washington, DC : National Acad. of Sciences, 1915
• Jahr Quelle: 2019
• Band/Heft Quelle: 116(2019), 10, Seite 4637-4642
• ISSN Quelle: 1091-6490
• DOI: doi:10.1073/pnas.1813562116
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: interferon-gamma
• Sach-SW: microglia
• Sach-SW: neuroinflammation
• Sach-SW: neuronal electrical activity
• Sach-SW: nitric oxide synthase
• K10plus-PPN: 1666492760

Abstract

Type II IFN (IFN-γ) is a proinflammatory T lymphocyte cytokine that serves in priming of microglia—resident CNS macrophages—during the complex microglial activation process under pathological conditions. Priming generally permits an exaggerated microglial response to a secondary inflammatory stimulus. The impact of primed microglia on physiological neuronal function in intact cortical tissue (in situ) is widely unknown, however. We explored the effects of chronic IFN-γ exposure on microglia in hippocampal slice cultures, i.e., postnatal parenchyma lacking leukocyte infiltration (adaptive immunity). We focused on fast neuronal network waves in the gamma-band (30-70 Hz). Such gamma oscillations are fundamental to higher brain functions, such as perception, attention, and memory, and are exquisitely sensitive to metabolic and oxidative stress. IFN-γ induced substantial morphological changes and cell population expansion in microglia as well as moderate up-regulation of activation markers, MHC-II, CD86, IL-6, and inducible nitric oxide synthase (iNOS), but not TNF-α. Cytoarchitecture and morphology of pyramidal neurons and parvalbumin-positive inhibitory interneurons were well-preserved. Notably, gamma oscillations showed a specific decline in frequency of up to 8 Hz, which was not mimicked by IFN-α or IL-17 exposure. The rhythm disturbance was caused by moderate microglial nitric oxide (NO) release demonstrated by pharmacological microglia depletion and iNOS inhibition. In conclusion, IFN-γ priming induces substantial proliferation and moderate activation of microglia that is capable of slowing neural information processing. This mechanism might contribute to cognitive impairment in chronic brain disease featuring elevated IFN-γ levels, blood-brain barrier leakage, and/or T cell infiltration, well before neurodegeneration occurs.