Co-culture of iPSC-derived microglia and spinal motor neurons as a novel model for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a fatal neurodegenerative disorder primarily characterized by motor neuron degeneration with additional involvement of non-neuronal cells, in particular, microglia. In our previous work, we have established protocols for the differentiation of iPSC-derived spinal motor neurons and microglia. Here, we combine both cell lineages and establish a novel co-culture of iPSC-derived motor neurons and microglia, which is compatible with motor neuron identity and function. Co-cultured microglia express key microglial markers and transcriptomically resemble primary human microglia, have highly dynamic ramifications, are phagocytic, release various cytokines and respond to stimulation. Further, they express key amyotrophic lateral sclerosis-associated genes and release disease-relevant biomarkers. This novel and authentic human model system facilitates the study of physiological motor neuron-microglia crosstalk and permits the investigation of non-cell-autonomous phenotypes in amyotrophic lateral sclerosis. Overall design: We sequenced a total of 12 samples, with 2 sequence runs per sample. The samples included 3 different cell types: iPSC macrophage precursors, iPSC microglia grown in monoculture and iPSC microglia grown in co-culture with iPSC motor neurons and extracted using CD11b MACS. Each cell type was generated from four different healthy control lines.