COX-1/EP1R Inhibition Ameliorate Deficits in Adult Neurogenesis and Social Interaction via Alleviating NLRP3/ IL-1β Activation During Hypobaric Hypoxia

Abstract

BackgroundLow oxygen environments like hypobaric hypoxia (HH) are common nodes to various diseases: characterized by neuroinflammation, which is detrimental to the structural and functional aspects of hippocampal circuitry. Various hypoxic conditions also lead to elevation of NLRP3 mediated neuroinflammation that may contribute to cognitive deficits. Components of neurogenic niches like microglia and astrocyte are largely affected by neuroinflammation; however, a systematic investigation of the impact of NLRP3 mediated neuroinflammation on components of neurogenic niche during hypoxia (HH) remains elusive. MethodsIn this study, we simulated cerebral hypoxia via decreasing partial pressure of oxygen(HH). The effect of hypobaric hypoxic (1, 3 and 7 day at 25000 ft) on social memory, anxiety, adult neurogenesis change in the inflammatory milieu in DG was explored in detail. We explored the efficacy of COX-1 inhibitor (Valery salicylate, 5mg/kg/day,i.p), and EP1R antagonist (SC19220, 1mg/kg/day,i.p) on NLRP3 mediated neuroinflammation and associated maladies during HH. ResultsWe observed that HH exposure induced alteration in social and anxiety-like behavior post 7 day exposure along with perturbation in levels of BDNF, Serotonin and adult neurogenesis in the DG right from day 1. Moreover, significant elevated NLRP3, caspase-1, and IL-1β levels are observed during HH from day 1. Concomitantly, a notable increase in the COX-1/EP1 pathway in both activated microglia and astrocyte in DG was evident after 3HH exposure. Pharmacological COX-1 inhibitor and EP1 antagonist counteract the detrimental effects of HH exposure on social memory, adult neurogenesis, and NLRP3 inflammasome induction. ConclusionsThus, our data showed induction of the COX-1/EP1 pathway in glial cells is detrimental to adult neurogenesis and social memory, raising possibility that the COX-1/EP1 pathway as a plausible target for inflammasome related neurogenesis impairment.