Astrocytes decrease adult neurogenesis during virus-induced memory dysfunction via IL-1

• Published in: Nature immunology Vol. 19; no. 2; pp. 151 - 161
• Main Authors: Garber, Charise, Vasek, Michael J., Vollmer, Lauren L., Sun, Tony, Jiang, Xiaoping, Klein, Robyn S.
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01.02.2018; Nature Publishing Group
• Subjects: Analysis; Astrocytes; Biomedical and Life Sciences; Biomedicine; Cognitive ability; Cognitive disorders; Criminal investigation; Cytokines; Genes; Hippocampus; Homeostasis; Immunological memory; Immunology; Infectious Diseases; Inflammation; Interleukin 1; Interleukin 1 receptors; Interleukins; Invasiveness; Memory; Microglia; Neural stem cells; Neuroblasts; Neurogenesis; Neurons; Progenitor cells; Rodents; Spatial discrimination; Spatial discrimination learning; Spatial memory; Synapses; Synaptogenesis; Transcription; Transcription (Genetics); Vector-borne diseases; West Nile fever; West Nile virus
• ISSN: 1529-2908; 1529-2916
• DOI: 10.1038/s41590-017-0021-y

Memory impairment following West Nile virus neuroinvasive disease (WNND) is associated with loss of hippocampal synapses with lack of recovery. Adult neurogenesis and synaptogenesis are fundamental features of hippocampal repair, which suggests that viruses affect these processes. Here, in an established model of WNND-induced cognitive dysfunction, transcriptional profiling revealed alterations in the expression of genes encoding molecules that limit adult neurogenesis, including interleukin 1 (IL-1). Mice that had recovered from WNND exhibited fewer neuroblasts and increased astrogenesis without recovery of hippocampal neurogenesis at 30 d. Analysis of cytokine production in microglia and astrocytes isolated ex vivo revealed that the latter were the predominant source of IL-1. Mice deficient in the IL-1 receptor IL-1R1 and that had recovered from WNND exhibited normal neurogenesis, recovery of presynaptic termini and resistance to spatial learning defects, the last of which likewise occurred after treatment with an IL-1R1 antagonist. Thus, ‘preferential’ generation of proinflammatory astrocytes impaired the homeostasis of neuronal progenitor cells via expression of IL-1; this might underlie the long-term cognitive consequences of WNND but also provides a therapeutic target. Klein and colleagues show, in a mouse model of West Nile virus–induced cognitive dysfunction, that neurogenesis is impaired by production of IL-1 from pro-inflammatory astrocytes.