KOLF2.1J iTF-Microglia: A standardized platform to study microglial transcriptional regulatory networks in CNS disease [Hi-C]

Understanding transcriptional regulatory networks (TRNs) in microglia is key to uncovering mechanisms driving central nervous system (CNS) disorders. Human iPSC-derived models offer a tractable system for studying microglia, yet variability between lines has limited reproducibility. Here, we use the standardized KOLF2.1J iTF line to rapidly generate microglia-like cells (iTF-Microglia) and profile TRNs under homeostatic and inflammatory conditions. iTF-Microglia closely resemble primary brain microglia at both transcriptomic and epigenomic levels. Integrative analyses reveal microglia-enriched candidate cis-regulatory elements (cCREs) and dynamic enhancer remodeling upon differentiation and LPS+IFNG stimulation, involving key transcription factors (TFs) including NF-kB, IRF, and STAT families. TRNs active in iTF-Microglia are enriched for genetic variants linked to Alzheimer’s disease and other CNS disorders. These findings establish KOLF2.1J iTF-Microglia as a reproducible and genetically tractable platform for studying human microglial gene regulation and provide mechanistic insight into how TRN remodeling may contribute to CNS disease risk. HiC profiling of untreated KOLF2.1J iTF-iPSCs and Day 18 KOLF2.1J iTF-Microglia that were either untreated or stimulated with 100 ng/mL LPS and 20 ng/mL IFNG for 24 hours