Human iPSC-derived proinflammatory macrophages cause insulin resistance in an isogenic white adipose tissue microphysiological system

Chronic white adipose tissue (WAT) inflammation has been recognized as a critical early event in the pathogenesis of obesity-related disorders. This process is characterized by the increased residency of proinflammatory M1 macrophages in WAT. However, the lack of an isogenic human macrophage-adipocyte model has limited biological studies and drug discovery efforts, highlighting the need for human stem cell-based approaches. Here, human induced pluripotent stem cell (iPSC) derived macrophages (iMACs) and adipocytes (iADIPOs) are cocultured in a microphysiological system (MPS). iMACs migrate toward and infiltrate into the 3D iADIPOs cluster to form crown-like structures (CLSs)-like morphology around damaged iADIPOs, recreating classic histological features of WAT inflammation seen in obesity. Significantly more CLS-like morphologies formed in aged and palmitic acid-treated iMAC-iADIPO-MPS, showing the ability to mimic inflammatory severity. Importantly, M1 (proinflammatory) but not M2 (tissue repair) iMACs induced insulin resistance and dysregulated lipolysis in iADIPOs. Both RNAseq and cytokines analyses revealed a reciprocal proinflammatory loop in the interactions of M1 iMACs and iADIPOs. Our iMAC-iADIPO-MPS thus successfully recreates pathological conditions of chronically inflamed human WAT, allowing us to study the dynamic inflammatory progression and identify clinically relevant therapies. To study interaction between isogenic macrophages and adipocytes derived from the same iPSC line, these two types of cells were monocultured in 24-well plate or cocultured in trans-well settings with 3 biological replicates per condition for 2 days. Macrophages in trans-wells and adipocytes in 24-well culture plates were respectively lysed and purified for bulk RNA that was RNA-seq analysized by Novogene. Genes of interests were then selected based on the relevance to iMAC-iAdipo interaction, and replotted based on data in DAVID analysis (The Database for Annotation, Visualization, and Integrated Discovery).