Integrated Multi-Omic Analysis Reveals KDM5B as a Regulator of Microglial Reactivity to Immunomodulatory Stimuli

Microglia maintain brain homeostasis through coordinated pathways, including cell migration, phagocytosis, and secretion of immune-related signaling factors. Microglial reactivity is associated with a variety of functional outcomes that are highly context-dependent withepigenetic regulation through DNA methylation and histone modifications implicated in this complex control of microglial plasticity. Specifically, in relation to histone methylation, lysine-specific demethylase 5B (KDM5B) has been associated with several pathophysiological states, including neurodevelopmental and inflammatory disorders, cancer, and alcohol use disorder (AUD); however, the cell-type-specific role of KDM5B in microglial reactivity has not been investigated. In this study, transcriptomic and proteomic analyses were used to characterize the effects of KDM5B depletion on microglial pathways in clustered regularly interspaced short palindromic repeats (CRISPR)-edited adult-derived murine microglial cells. Additionally, various immunomodulatory stimuli, including lipopolysaccharide (LPS), interleukin-4, and alcohol, were used to study the effects of KDM5B depletion on immune reactivity in microglia using deep proteomics and bioinformatic analysis. Through this comprehensive characterization, KDM5B-depleted microglia exhibited broad remodeling of immune reactivity, including reduced intracellular and secreted inflammatory responses to lipopolysaccharide as well as distinct modulation of alcohol- and interleukin-4-induced pathways, that was functionally demonstrated by altered cytokine secretion profiles. Results from this study provide critical insight into KDM5B-mediated immunological effects on microglial function.