A 3D In Vitro Model of the Human Hepatobiliary Junction.

Bile flow is an essential feature of the liver, and disruption of this process contributes to a range of liver pathologies. Efficient bile transport requires coordinated organization between hepatocytes and cholangiocytes at the hepatobiliary junction, a structure that remains poorly captured in existing in vitro models of liver disease. Here, we present a 3D multicellular spheroid-based model of the human hepatobiliary junction. Building on advances in organoid and spheroid engineering, we co-aggregate human hepatocytes and intrahepatic cholangiocytes, supported by murine fibroblasts, into adult hepatobiliary organoids (aHBOs). aHBOs directionally transport bile from hepatocyte canaliculi to cholangiocyte-lined ductule-like structures, visualized through a high-throughput imaging assay. Hepatobiliary junction formation and bile flow dynamics are quantified over time using a fluorescent bile acid analog and AI-assisted image analysis. When subjected to hypoxia-reoxygenation, aHBOs exhibit disrupted bile transport and distinct cell-type-specific responses, enabling interrogation of hepatocyte and cholangiocyte vulnerability to transplant-associated biliary hypoxia. Our findings suggest a reversible reduction in hepatocyte canalicular function under hypoxia, followed by selective cholangiocyte death upon reoxygenation, potentially contributing to biliary dysfunction after ischemic injury. This human-derived, scalable platform provides a phenotypically relevant model for dissecting mechanisms of biliary dysfunction and discovering therapeutics for hypoxic liver injury and cholestatic diseases.