A VERSATILE TOOLBOX OF HUMAN IPSC-DERIVED MICROGLIA FOR DISEASE MODELLING AND MULTICELLULAR IN VITRO MODELS FOR NEURODEGENERATION DRUG DISCOVERY

Microglia are resident macrophages of the central nervous system (CNS) and are essential for neural homeostasis; they regulate neurogenesis, synaptic remodelling, and are first responders to injury. Despite the critical role of microglia in CNS health, existing in vitro models fail to replicate microglia biology.
Here, we use opti-ox™, a deterministic cell programming technology, to generate scalable human-induced pluripotent stem cell derived microglia (ioMicroglia). The transcriptional profile of ioMicroglia aligns closely with publicly available datasets of adult and foetal human microglia, confirming that this model effectively recapitulates microglia biology. ioMicroglia express CD45, P2RY12, CD11b, CD14, IBA1, and TREM2 proteins and are functionally competent. ioMicroglia demonstrate robust pro-inflammatory cytokine secretion and phagocytic activity in response to both amyloid beta-42 and bacterial particles. These core functionalities were demonstrated as early as day 4 post-thaw, providing a fast time frame to perform key assays.
ioMicroglia also demonstrate a P2RY12 mediated chemotactic response to ATP, the “find me” signal released by damaged neurons. The P2RY12-/- ioMicroglia enables further exploration of this function by providing genetic ablation of this key purinergic sensor. In addition, we engineered ioMicroglia with mutations associated with Alzheimer's disease, including TREM2 (R47H) and APOE (C112R). Lastly, we showcase a co-culture of ioMicroglia and ioGlutamatergic Neurons to demonstrate tractable in vitro modelling of CNS physiology with the ioCells.
This work demonstrates how ioMicroglia can provide physiologically relevant human in vitro modelling of microglia function in health and disease.