Minghui Wang, United States of America
Icahn School of Medicine at Mount Sinai Genetics and Genomic SciencesAuthor Of 1 Presentation
CHOLESTEROL AND MATRISOME PATHWAYS DYSREGULATED IN HUMAN APOE Ε4 GLIA
Abstract
Aims
The association of Apolipoprotein E (APOE) ɛ4 with Alzheimer's disease risk is well-established however, the impact of APOE ɛ4 on human brain cell function remains unclear. We hypothesized that human APOE ε4/ε4 genotype contributes to disease risk through cell autonomous and non-cell autonomous mechanisms in a human specific manner.
Methods
Global transcriptomic analysis (pathway, network and cell type deconvolution) were performed on brain cell types, astrocytes, microglia, mixed cortical cultures (neurons and astrocytes) and brain microvascular endothelial cells, derived from human induced pluripotent stem cells (population and isogenic cells), post-mortem brains and APOE targeted replacement mice. For in vitro mechanistic study, filipin staining, Gas Chromatography/Mass Spectrometry (GC/MS), live cell imaging, immunocytochemistry, and Luminex multiplex immunoassays were utilized for lipid trafficking, the measurement of intracellular cholesterol level, localization, and cytokine/chemokine secretion.
Results
Global transcriptomic analyses identified human specific APOE ε4-driven lipid metabolic dysregulation in astrocytes and microglia. Decoupled cholesterol metabolism in APOE ε4 glia is due to lysosomal cholesterol sequestration; despite increased intracellular cholesterol leads to elevated de novo synthesis and decreased efflux. The most significant upregulated signal in post-mortem APOE ε4 AD brains is matrisome associated with chemotaxis, glial activation and lipid biosynthesis, which derives from astrocytes, paralleled pathways uncovered in astrocytes when co-cultured with neurons. Further, APOE ε4 astrocytes show enhanced chemokine/proinflammatory factors production when communicating with neurons.
Conclusions
Human APOE ε4 initiates human glia-specific cell autonomous and non-cell autonomous dysregulation that may increase AD risk.