For in vivo experiments, mice were i.p. injected with either 200 μL E. coli 0111:B4 (Sigma-Aldrich, catalog no. L2630, EC no. 297-473-0) or PBS as control. The dose of LPS was 5 mg/kg and mice were culled after 4 hours, except for sickness behavior experiments where a lower dose of 0.33 mg/kg was used. For aging experiments, mice used were 2–6 months (young) or 14–18 months (old) of age. For experiments with Rheb1fl/fl Csf1rCre mice, male and female mice were used at 2–6 months (young) and 15–20 months (old) of age. Rheb1fl/fl without Cre or Rheb1+/+ Csf1rCre-positive mice were used as WT controls.