Acute fasting inhibits central caspase-1 activity reducing anxiety-like behavior and increasing novel object and object location recognition

Albert E. Towers, Maci L. Oelschlager, Jay Patel, Stephen J. Gainey, Robert H. McCusker, Gregory G. Freund

Research output: Contribution to journalArticle

Abstract

Background Inflammation within the central nervous system (CNS) is frequently comorbid with anxiety. Importantly, the pro-inflammatory cytokine most commonly associated with anxiety is IL-1β. The bioavailability and activity of IL-1β are regulated by caspase-1-dependent proteolysis vis-a-vis the inflammasome. Thus, interventions regulating the activation or activity of caspase-1 should reduce anxiety especially in states that foster IL-1β maturation. Methods Male C57BL/6j, C57BL/6j mice treated with the capase-1 inhibitor biotin-YVAD-cmk, caspase-1 knockout (KO) mice and IL-1R1 KO mice were fasted for 24 h or allowed ad libitum access to food. Immediately after fasting, caspase-1 activity was measured in brain region homogenates while activated caspase-1 was localized in the brain by immunohistochemistry. Mouse anxiety-like behavior and cognition were tested using the elevated zero maze and novel object/object location tasks, respectively. Results A 24 h fast in mice reduced the activity of caspase-1 in whole brain and in the prefrontal cortex, amygdala, hippocampus, and hypothalamus by 35%, 25%, 40%, 40%, and 40% respectively. A 24 h fast also reduced anxiety-like behavior by 40% and increased novel object and object location recognition by 21% and 31%, respectively. IL-1β protein, however, was not reduced in the brain by fasting. ICV administration of YVAD decreased caspase-1 activity in the prefrontal cortex and amygdala by 55%, respectively leading to a 64% reduction in anxiety like behavior. Importantly, when caspase-1 KO or IL1-R1 KO mice are fasted, no fasting-dependent reduction in anxiety-like behavior was observed. Conclusions Results indicate that fasting decrease anxiety-like behavior and improves memory by a mechanism tied to reducing caspase-1 activity throughout the brain.

Original languageEnglish (US)
Pages (from-to)70-82
Number of pages13
JournalMetabolism: Clinical and Experimental
Volume71
DOIs
StatePublished - Jun 1 2017

Keywords

  • Anxiety
  • Caspase-1
  • Fasting
  • Il-1β
  • Neuroinflammation

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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