Dietary Intervention with the Gut Microbial Metabolite Urolithin A Attenuates Lipopolysaccharide-Induced Neuroinflammation and Cognitive Deficits via the Sirt1/acetyl-NF-κB Signaling Pathway.

Abstract

The gut microbial metabolite Urolithin A (UA) exhibits anti-inflammatory properties in vivo and in vitro. Lipopolysaccharide (LPS), which is present in abundance in the gut, induces chronic neuroinflammation and triggers behavioral abnormalities. However, the neuroprotective effects of UA and the underlying mechanisms implicate in an LPS-elicited neuroinflammation mouse model remain elusive. Daily administration of UA (200mg kg-1 d-1 ; i.g.) for 21 days significantly mitigates cognitive deficits following LPS exposure. UA prevents LPS-induced neural loss and synaptic injury in the hippocampus. UA administration substantially represses LPS-triggered glial cell activation and the production of proinflammatory cytokines (TNF-α, IL-1β, and IL-6). Further study reveals that UA promotes Sirt1 expression and NF-κB p65 deacetylation. Importantly, all the beneficial effects of UA, including biochemical and neuropathological changes and cognitive function, are abrogated by 6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide (EX-527), a specific Sirt1 inhibitor. The findings indicate that UA ameliorates LPS-triggered neural/synaptic damage and cognitive deficits, which potentially contributes to the inhibition of neuroinflammation by promoting the Sirt1/acetyl-NF-κB signaling pathway.