APOE4 drives transcriptional heterogeneity and maladaptive immunometabolic responses of astrocytes (bulk RNA-Seq)

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: Isogenic APOE33 and APOE44 astrocytes (see 10.1016/j.cell.2022.05.017) were seeded in 24 well plate at a density of ~109k cells/well. Cells were treated with vehicle or 3ng/mL IL-1a, 30ng/mL TNF, and 400ng/mL C1q for 4 hours. Following treatment, media was apirated, cells washed with sterile DPBS. Following wash, cells were lysed with RLTplus buffer and RNA harvested per manufacturer's suggested protocol (Qiagen # 74034).