APOE4 drives transcriptional heterogeneity and maladaptive immunometabolic responses of astrocytes (Spatial)

Apolipoprotein 4 (APOE4), is the strongest genetic risk allele associated with the development of late onset Alzheimer's disease (AD). Across the CNS, astrocytes are the predominant expressor of Apoe while also being critical mediators of neuroinflammation and cerebral metabolism. APOE4 has been consistently linked with dysfunctional neuro-immunometabolism, however insights into the molecular constituents driving these responses remain unclear. Utilizing complimentary approaches across humanized ApoE expressing mice and isogenic IPS astrocytes, we demonstrate that harboring ApoE4 alters astrocyte immunometabolic response to pro-inflammatory stimuli. Our findings demonstrate that ApoE4-expressing astrocytes acquire distinct transcriptional repertoires at the single-cell and spatially-resolved domains, which driven, in-part, by preferential utilization of the cRel transcription factor. Further, inhibiting cRel translocation abrogated inflammatory-induced glycolytic shift and ultimately resulted in significantly dampened glycolysis-associated metabolites in tandem with mitigating production of multiple pro-inflammatory cytokines. Altogether, our findings elucidate novel cellular underpinnings by which ApoE4 drives maladaptive immunometabolic responses of astrocytes. Overall design: Male, targeted replacement humanized APOE33 and APOE44 mice were used for these studies. 5mg/kg LPS was administered systemically via IP injection and mice were euthanized 24hrs later.