04134nas a2200577 4500000000100000008004100001260001500042653001600057653001800073653003300091653001300124653002000137653001700157653001000174100001800184700001800202700001500220700001900235700001600254700001800270700002000288700001700308700002000325700001800345700001300363700001700376700001600393700002300409700001900432700002000451700001700471700001900488700001900507700002900526700001900555700001700574700002500591700001900616700002100635700002200656700001800678700002100696700001800717700001900735700002100754700002000775245009800795856007200893520257700965022001403542 2025 d c2025-12-1710aFetal Liver10aHematopoiesis10ahuman pluripotent stem cells10aImmunity10aliver organoids10aMyelopoiesis10aiPSCs1 aMilad Rezvani1 aSusanna Quach1 aKyle Lewis1 aNorikazu Saiki1 aChuqing Xue1 aMasaki Kimura1 aKentaro Iwasawa1 aJulian Weihs1 aTahlil Elzobair1 aHasan Al Reza1 aYuqi Cai1 aRanRan Zhang1 aYuka Milton1 aPraneet Chaturvedi1 aKonrad Thorner1 aRamesh C. Nayak1 aJorge Munera1 aPhillip Kramer1 aBrian R. Davis1 aAppakalai N. Balamurugan1 aYeni Ait Ahmed1 aMarcel Finke1 aRose Yinghan Behncke1 aAdrien Guillot1 aRené Hägerling1 aJulia K. Polansky1 aPhilip Bufler1 aJose A. Cancelas1 aAaron M. Zorn1 aJames M. Wells1 aMomoko Yoshimoto1 aTakanori Takebe00aModeling immune lineage co-development in human pluripotent stem cell-derived liver organoids uhttps://www.sciencedirect.com/science/article/pii/S01688278250265713 aBackground & Aims Intercellular orchestration across hepatic and immune lineages governs critical liver development and disease processes. Existing in vitro human liver models limit immune lineage outputs partly due to the lack of an endogenous niche for blood co-development. By modeling a developmental niche, we developed human fetal liver-like organoids (FLOs) harboring a multipotent hematopoietic system to model and study the complex multilineage interaction in liver development and injury. Methods We generated FLOs from human pluripotent stem cells to study cross-lineage self-organization by co-developing a hemogenic mesoderm and hepatic endoderm. Hematopoietic progenitor cell and epithelial lineage potential and dynamics were assessed through single-cell and bulk transcriptomics, immunophenotyping, and functional assays. Results FLOs established a bona fide niche that supports the simultaneous emergence of hepatobiliary, endothelial, and mesenchymal lineages, along with multipotent hematopoietic progenitor cells exhibiting predominant myeloid lineage commitment while retaining the potential for fetal B and T cell differentiation. Within the FLO microenvironment, hepatic and hematopoietic lineages continued to mature in the absence of extrinsic differentiation factors. Enriching hematopoietic derivatives with a small molecule-cytokine cocktail generated divergent immune cell populations, including granulocytes and polarized macrophages equipped with immunoreactive and lineage-specific function. Finally, FLOs mechanistically revealed an IL-8-mediated neutrophil-driven injury response upon steatotic-lipotoxic injury, highlighting key liver-intrinsic immune mechanisms. Conclusions FLOs provide a physiologically relevant model for multi-lineage hemato-hepatogenesis and innate immunity in the liver. By recapitulating critical fetal liver tissue functions, FLOs offer a translational platform for studying human fetal liver development, immune-mediated hepatic injury, and regenerative therapies. Impact and implications This study establishes a human pluripotent stem cell-derived fetal liver-like organoid (FLO) system that reconstitutes hepato-hematopoietic co-development and innate immune function. FLOs offer a human platform to dissect cross-lineage signaling during liver development and immune-mediated injury. Clinically and translationally, FLOs enable mechanistic modeling of pediatric liver diseases and regenerative interventions, offering a tractable in vitro system for preclinical screening and precision-medicine approaches. a0168-8278