Targeting the intersection of angiopoietin-TIE2 signaling with arachidonic acid metabolism can prevent septic death

Neonatal sepsis is a major cause of childhood mortality. Limited diagnostic tools and mechanistic insights have hampered our abilities to develop prophylactic or therapeutic interventions. Biomarkers in human neonatal sepsis have been repeatedly identified as associated with dysregulation of angiopoietin signaling and altered arachidonic acid metabolism. We here show that these two pathways appear to be functionally connected via reactive oxygen species (ROS) with a direct role of nitric oxide (NO). Targeting this intersection with oral administration of arachidonic acid and/or the NO donor L-arginine provided prophylactic as well as therapeutic protection from septic death. The neonatal sepsis model was utilized as previously described. In short, CS was obtained from adult male caeca and resuspended in dextrose 5% water at a concentration of 100mg/mL and then passed through a 70um filter. To provide consistency, our cecal slurry model (PMID: 30741260) employs multiple litters of adult donors of cecal slurry that are pooled, mixed and aliquots were frozen at -80°C until challenge. Following this, each slurry is titred to determine the effective dose (LD50 etc.). Each new cecal slurry lot is directly compared to previous lots to ensure consistency across experiments. Neonatal mice at day of life (DOL) 6-8 were challenged via intraperitoneal injection at a weight adjusted dose of 1mg/g body weight. Litter-to-litter variation was accounted for by having a balanced number of treated and control mice in each litter. 10 neonatal mice did not receive cecal slurry challeng while 25 neonatal mice received cecal slurry.