Human Remyelination Promoting Antibody Stimulates Astrocytes Proliferation Through Modulation of the Sphingolipid Rheostat in Primary Rat Mixed Glial Cultures

Circadian dysfunction is a common attribute of many neurodegenerative diseases, most of which are associated with neuroinflammation. Circadian rhythm dysfunction has been associated with inflammation in the periphery, but the role of the core clock in neuroinflammation remains poorly understood. Here we demonstrate that Rev-erbα, a nuclear receptor and circadian clock component, is a mediator of microglial activation and neuroinflammation. We observed time-of-day oscillation in microglial immunoreactivity in the hippocampus, which was disrupted in Rev-erbα−/− mice. Rev-erbα deletion caused spontaneous microglial activation in the hippocampus and increased expression of proinflammatory transcripts, as well as secondary astrogliosis. Transcriptomic analysis of hippocampus from Rev-erbα−/− mice revealed a predominant inflammatory phenotype and suggested dysregulated NF-κB signaling. Primary Rev-erbα−/− microglia exhibited proinflammatory phenotypes and increased basal NF-κB activation. Chromatin immunoprecipitation revealed that Rev-erbα physically interacts with the promoter regions of several NF-κB–related genes in primary microglia. Loss of Rev-erbα in primary astrocytes had no effect on basal activation but did potentiate the inflammatory response to lipopolysaccharide (LPS). In vivo, Rev-erbα−/− mice exhibited enhanced hippocampal neuroinflammatory responses to peripheral LPS injection, while pharmacologic activation of Rev-erbs with the small molecule agonist SR9009 suppressed LPS-induced hippocampal neuroinflammation. Rev-erbα deletion influenced neuronal health, as conditioned media from Rev-erbα–deficient primary glial cultures exacerbated oxidative damage in cultured neurons. Rev-erbα−/− mice also exhibited significantly altered cortical resting-state functional connectivity, similar to that observed in neurodegenerative models. Our results reveal Rev-erbα as a pharmacologically accessible link between the circadian clock and neuroinflammation.

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A Refined Bead-Free Method to Identify Astrocytic Exosomes in Primary Glial Cultures and Blood Plasma

Frontiers in Neuroscience ◽

10.3389/fnins.2017.00335 ◽

2017 ◽

Vol 11 ◽

Cited By ~ 12

Author(s):

Cory M. Willis ◽

Antoine Ménoret ◽

Evan R. Jellison ◽

Alexandra M. Nicaise ◽

Anthony T. Vella ◽

...

Keyword(s):

Blood Plasma ◽

Glial Cultures ◽

Primary Glial Cultures

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Metabolism of Angiotensin Peptides by Neuronal and Glial Cultures from Rat Brain

Journal of Neurochemistry ◽

10.1111/j.1471-4159.1989.tb02534.x ◽

1989 ◽

Vol 52 (3) ◽

pp. 863-868 ◽

Cited By ~ 13

Author(s):

Klaus Hermann ◽

M. Ian Phillips ◽

Mohan K. Raizada

Keyword(s):

Rat Brain ◽

Angiotensin Peptides ◽

Glial Cultures

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Abstract T P80: Inhibition of Ezh2 Leads to Decreased M1 and Enhanced M2 Microglia Phenotypes

Stroke ◽

10.1161/str.46.suppl_1.tp80 ◽

2015 ◽

Vol 46 (suppl_1) ◽

Author(s):

Edward Koellhoffer ◽

Jeremy Grenier ◽

Rodney Ritzel ◽

Louise McCullough

Keyword(s):

Ischemic Stroke ◽

Pcr Analysis ◽

M2 Polarization ◽

M2 Microglia ◽

M1 Polarization ◽

Glial Cultures ◽

M2 Response ◽

M1 Phenotype ◽

Cayman Chemical ◽

M2 Phenotype

Background: Ischemic stroke results in the activation of microglia, which may polarize toward a pro-inflammatory (M1) phenotype or an anti-inflammatory, neuroprotective (M2) phenotype. Thus, simultaneously suppressing the M1 response and promoting the M2 response could be beneficial in the treatment of stroke. Recently, the epigenetic modulator Jmjd3 has been shown to be essential for M2 polarization. However, Jmjd3 is antagonized by Ezh2 which is associated with M1 polarization. Thus, we hypothesized that inhibition of Ezh2 tilts the balance between Jmjd3 and Ezh2, thereby enhancing polarization toward an M2 phenotype and improved outcome in ischemic stroke. Methods: Mixed glial cultures were isolated from P0.5-P2 C57BL/6J mice and cultured for 14 days before microglial isolation. Microglia were rested for 24 hours before treatment every other day with 6uM GSK343 (Cayman Chemical) or DMSO vehicle control. After 7 days, microglia were stimulated with LPS or IL-4 and RNA was isolated at 4hr and 24hr post-stimulation for qRT-PCR analysis. Results: LPS-induced IL6 and IL1B expression was significantly abrogated by 71% and 53%, respectively (p<0.05), at 24hr when Ezh2 was inhibited. Additionally, Ezh2 inhibition both increased baseline expression of M2-associated genes ARG1, CD206, and IRF4 by 196%, 257%, and 395%, respectively (p<0.05), and rescued their expression in the presence of LPS at 24hr (p<0.05) in which they were otherwise significantly down-regulated. Conclusion: Pharmacological inhibition of Ezh2 limits microglial M1 polarization and enhances M2 polarization.

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