Human iPSC-derived neurons and astrocytes as models of neurodegeneration, neuroinflammation and vesicular trafficking in Alzheimer's disease

Neural cells derived from human induced pluripotent stem cells (iPSCs) are innovative models for dissecting the pathological mechanisms of Alzheimer's disease (AD). However, in vitro differentiation of iPSCs to functional and mature neural cells is still not optimized. We generated/characterized iPSCs-derived neurons and astrocytes from controls and AD patients with PSEN1ΔE9 mutation. After one/two months of neurosphere differentiation, plated cells reached 30% of βIII-tubulin+ neurons with slightly higher levels of nitric oxide, compared to control. Astrocytes from astrospheres after five months of differentiation expressed S100B, but only 50% were GFAP+. AD astrocytes displayed a depressed functional phenotype with lower levels of miR-155 and RAGE mRNA, and released exosomes depleted in alarmins (HMGB1 and S100B). When stimulated to A1 inflammatory phenotype, these astrocytes acquired a fibroblast-like morphology and expressed elevated miR-155, when compared to control, while their exosomes contained increased levels of HMGB1 and S100B mRNA. Collectively, AD astrocytes differentiated from iPSCs reveal a deregulated inflammatory profile and a specific exosomal cargo.