Local interleukin-18 system in the basolateral amygdala regulates susceptibility to chronic stress

Tae Kyung Kim, Ji Eun Kim, Juli Choi, Jin Young Park, Jung Eun Lee, Eun Hwa Lee, Yunjin Lee, Bo Yeon Kim, Young J. Oh, Pyung Lim Han

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Abstract

Interleukin-18 (IL18) is a multifunctional cytokine that has been implicated in increased susceptibility to depression; however, the underlying mechanism remains unknown. We found that the IL18 system in the basolateral amygdala (BLA) determined susceptibility to chronic stress. Mice subjected to chronic restraint stress or chronic foot-shock stress demonstrated increased expression of IL18 in the BLA, and exhibited depression-like behaviors, whereas IL18 knockout (KO) mice were resilient to these chronic stresses. IL18 and IL18 receptors in the BLA were expressed in glutamatergic and GABAergic neurons in addition to glial cells. Local inhibition of IL18 and IL18 receptors in the BLA by stereotaxic injection of siRNA-IL18 or siRNA-IL18 receptor-1α was sufficient to suppress stress-induced depression-like behaviors. Following chronic stress, the downstream mediator of IL18 receptor activation, phospho-NF-kB, was increased in BLA neurons expressing IL18 receptors. Furthermore, siRNA-mediated inhibition of NF-kB in the BLA significantly suppressed stress-induced depression-like behaviors, and NF-kB KO mice were resilient to chronic stress. The siRNA-mediated inhibition of NF-kB in the BLA downregulated stress-induced increased expression of Hcrt, MCH, OXT, AVP, and TRH, the neuropeptides that were induced by chronic stress in the BLA and promoted depression-like behaviors. These results suggest that the local IL18 and its receptor system in the BLA function as molecular regulators promoting susceptibility to chronic stress.

Original languageEnglish
Pages (from-to)5347-5358
Number of pages12
JournalMolecular Neurobiology
Volume54
Issue number7
DOIs
Publication statusPublished - 2017 Jan 1

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All Science Journal Classification (ASJC) codes

  • Neurology
  • Cellular and Molecular Neuroscience

Cite this

Kim, T. K., Kim, J. E., Choi, J., Park, J. Y., Lee, J. E., Lee, E. H., Lee, Y., Kim, B. Y., Oh, Y. J., & Han, P. L. (2017). Local interleukin-18 system in the basolateral amygdala regulates susceptibility to chronic stress. Molecular Neurobiology, 54(7), 5347-5358. https://doi.org/10.1007/s12035-016-0052-7