P17-17 Human iPSC-derived microglia-like cells for functional inflammatory assays, toxicity testing, and co-culture applications

Microglia, the resident immune cells of the central nervous system, are critical regulators of neural development, homeostasis, and neuroinflammatory processes. Despite their importance, experimental models enabling the study of compounds that modify human microglial responses remain limited. Moreover, the overwhelming majority of microglia activation and modification studies use a single inflammogen: lipopolysaccharide (LPS). Here, we generated microglia-like cells (MGLCs) from human induced pluripotent stem cells (iPSCs) that express characteristic microglial markers and exhibit key functions, including phagocytosis and stimulus-dependent cytokine release. Upon exposure to ligands of various Toll-like receptors (LPS, Poly(I:C), FSL-1, Imiquimod) or cytokines (TNFα, IFNγ), MGLCs displayed distinct activation profiles. Comparative analyses of NFκB translocation in MGLCs and astrocytes revealed differential responsiveness to identical stimuli. Moreover, conditioned medium from activated MGLCs induces NFκB translocation in astrocytes, indicating functional crosstalk between glial cell types. Pharmacological inhibition of the MGLCs’ NFκB pathway was tested for a large panel of test compounds. Our findings highlight the utility of NFκB translocation assays in MGLCs and astrocytes as a platform for the screening of compounds that modulate glial inflammatory responses.