The AhR agonist FICZ inhibits apoptosis and allows for the exponential expansion of iPSC-derived HPs. (A) Representative FACS analysis of live vs dead or dying cells (propidium iodide [PI] vs Hoechst) from day 15 HPs ± FICZ. Plots were gated first in forward light scatter (FSC) vs side light scatter (SSC) and then from that population for PI⁺ and PI^- Hoechst⁺. (B) FICZ increases the population of live cells, as delineated by FSC and SSC, and decreases the number of compromised or apoptotic cells. For the live-cell gate, data are the average of 3 independent experiments ± SD: *P < .01. For the apoptotic cell gate, data are the average of 3 independent experiments ± SD: *P < .02. (C) EdU proliferation assay comparing day 15 HPs ± FICZ. After FICZ stimulation on day 7, EdU incorporation into treated HPs was significantly increased compared with untreated controls, indicative of increased proliferation. Data are the average of 3 independent experiments ± SD: *P < .01. (D) Representative phase-contrast images of HP population ± FICZ. (E) Growth curve of day 15 HPs ± 0.2 μm of FICZ. Cells were counted manually using trypan blue exclusion. Graphical data and the associated statistics are the result of 3 independent experiments per group.