Interleukin-6 Induced by Social Stress Promotes a Unique Transcriptional Signature in the Monocytes That Facilitate Anxiety.

Niraula A, Witcher KG, Sheridan JF, Godbout JP
Biol Psychiatry 85 679-689 04/15/2019

Abstract

BACKGROUND: Interleukin-6 (IL-6) is elevated in circulation with chronic stress and may contribute to neurobehavioral complications. We have reported that repeated social defeat stress in mice caused recruitment of proinflammatory monocytes to the brain and triggered the onset of anxiety-like behavior. Therefore, the purpose of this study was to determine the role of IL-6 signaling in the peripheral immune response, neuroinflammation, and anxiety following stress.

METHODS: Wild-type and IL-6 knockout mice were subjected to repeated social defeat, and immune and behavioral parameters were determined 14 hours later.

RESULTS: Although monocyte release and recruitment to the brain during stress were maintained in the IL-6 knockout mice, anxiety and social avoidance were prevented. NanoString analysis of fluorescence-activated cell-sorted blood monocytes (CD11b

CONCLUSIONS: Here, we show the effects of IL-6 on the transcriptional signature of monocytes in circulation and brain after stress. Overall, robust increases in IL-6 after stress induced a primed profile in monocytes that were recruited to the brain and propagated IL-1-mediated inflammation and anxiety.

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