Modeling sporadic Alzheimer’s disease in human brain organoids under serum exposure

Although sporadic AD (sAD) accounts for the majority of AD cases, the underlying mechanisms remain largely unknown. Here we modeled sAD using human induced pluripotent stem cell (iPSC)-derived three-dimensional brain organoids. We exposed brain organoids to serum to mimic the serum exposure consequence of BBB breakdown in AD patient brains. The serum-exposed brain organoids were able to recapitulate AD-like pathologies, including increased Aβ aggregates and p-Tau level, synaptic loss, and impaired calcium signaling and neural network. Serum exposure increased Aβ and p-Tau levels through inducing BACE and GSK3α/β levels, respectively. In addition, single-cell transcriptomic analysis of brain organoids revealed that serum exposure reduced synaptic function in both neurons and astrocytes, and induced immune response in astrocytes. The human brain organoid-based sAD model established in this study could provide a powerful platform for both mechanistic study and therapeutic development. 14048 brain organoids (BO2) and ADRC28 brain organoids (BO3) were treated without (control) or with 10% human serum (8748 or 3821) for 13-14 days and then were harvested at day 94-95 for scRNA-seq