Microglia mediate neuroinflammation through surveillance of their environment and by cell surface receptor activation. Therefore, we tested iMGL response to extracellular stimuli observed in AD, such as nucleotides leaked from degenerating neurons. Microglia sense ADP release via purinergic receptors and we likewise find that iMGLs robustly express functional P2ry12 and migrate and exhibit calcium influx via an ADP-P2ry12 receptor mechanism. Also, iMGLs secrete a variety of cytokines in response to IFNγ, IL-1β, and LPS stimulation. Many of these cytokines are known to be highly elevated in neurological diseases and/or involved in the recruitment of peripheral immune cells into the CNS under pathological conditions (Chan et al., 2007; Prinz et al., 2011; Rezaie and Male, 1999; Stalder et al., 2005). Microglial-mediated cytokine secretion can further influence the inflammatory milieu in the CNS and thus represents an excellent therapeutic target for restoring CNS homeostatic balance. Together, migration, calcium imaging, and cytokine secretion assays not only validate iMGLs to be highly similar to brain-derived microglia but provide important functional assays to assess the role of microglia in neuroinflammation. Our data highlights the potential utility of iMGLs to identify therapeutic compounds via high throughput assessment of microglia physiology.
