MEMP PhD Thesis Defense: Ashley Westerfield

A 3D in vitro Model of the Human Hepatobiliary Junction

Cholestasis, or disruption in bile flow, is a poorly understood feature of many liver diseases and is a well-established indication for liver transplant. Despite this clinical significance, many tissue engineering strategies for modeling or treating liver disease fail to recapitulate physiological bile flow. Recent advances in the field of tissue engineering and organoid technology have enabled the culture of human hepatocytes and bile duct cells in vitro, these models lack a key function of the liver which is bile transport. In this thesis, I present a 3D multicellular spheroid model that captures the structure and function of the human hepatobiliary junction—the interface between liver and bile duct cells that is often disrupted in liver disease. By co-aggregating primary human hepatocytes and bile duct cells, I engineer a liver spheroid model that recapitulates physiological bile flow through a functional connection between the two cell types. These spheroids maintain cell polarity and transport bile from hepatocyte canaliculi to bile duct structures. This function is quantified by leveraging a high-throughput imaging assay with AI-assisted analysis to track junction formation and bile flow over time. I also use this system to model ischemic injury of the bile duct, a common complication of liver transplant, by tuning the oxygen parameters of the spheroid culture. In this injury model, I observe and describe two processes that potentially contribute to injury: a reversible loss of canalicular function during hypoxia, followed by selective bile duct cell death after reoxygenation. This human-based, scalable platform provides a new tool to study bile duct biology, understand mechanisms of biliary injury after liver transplant, and support drug discovery efforts for cholestatic liver diseases.

Thesis Supervisor:
Sangeeta N. Bhatia, M.D., Ph.D.
John J. and Dorothy Wilson Professor of Engineering, MIT

Thesis Committee Chair:
Alex K. Shalek, PhD
J. W. Kieckhefer Professor, Institute for Medical Engineering & Science, Department of Chemistry, and Koch Institute, MIT

Thesis Readers:
Christopher S. Chen, M.D., Ph.D.
William F. Warren Distinguished Professor of Biomedical Engineering, Boston University

Andrea I. McClatchey, Ph.D.
Professor of Pathology, Harvard Medical School & Massachusetts General Hospital Cancer Center

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Ashley Danielle Westerfield is inviting you to a scheduled Zoom meeting

Topic: Ashley Westerfield MEMP PhD Thesis Defense
Time: Monday, July 14, 2025, 10:00 AM Eastern Time (US and Canada)

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