A Matrix-Free 3D Hepatocyte-Macrophage Co-Culture Spheroid Model for Dual Assessment of Lipid Accumulation and...

Background/Objectives: Metabolic dysfunction-associated steatotic liver disease (MASLD) involves the interplay of hepatic lipid accumulation and immune-mediated inflammatory signaling, yet human-relevant in vitro systems that capture both processes simultaneously in a scalable format remain limited. The objective of this study was to develop and characterize a matrix-free 3D hepatocyte-macrophage co-culture model enabling simultaneous assessment of lipid accumulation and NF-κB-mediated inflammatory activation under glucolipotoxic stress. Methods: A 3D liver co-culture model was established by combining HepG2 hepatocyte-like cells with phorbol 12-myristate 13-acetate (PMA)-differentiated THP-1 macrophage-like cells stably expressing a NF-κB-Luc2 reporter. Spheroids were generated using a hanging-drop method in standard 96-well plates and matured for 8-10 days. Mature spheroids were subjected to acute 24 h glucolipotoxic challenge combining high glucose and palmitic acid and assessed for neutral lipid accumulation, NF-κB reporter activation (luciferase), and macrophage marker expression (qPCR). Results: Time-course characterization demonstrated progressive hepatocyte marker remodeling (albumin, alpha-fetoprotein, CYP3A4) and dynamic macrophage phenotype shifts (CD14, CD206, MARCO, TREM2). Acute glucolipotoxic challenge induced dose-dependent increases in neutral lipid accumulation and NF-κB reporter activation, accompanied by coordinated macrophage-associated transcriptional changes consistent with lipid-handling and tissue-remodeling programs. Post-challenge metabolic activity was retained under the selected stress conditions. As a proof-of-concept demonstration, three botanical extracts showed distinct attenuation profiles across the lipid and inflammatory endpoints. Conclusions: This 3D hepatocyte-macrophage co-culture model provides orthogonal readouts of steatosis and NF-κB-mediated inflammatory activation under glucolipotoxic stress, offering a reproducible, fit-for-purpose screening tool for investigating early glucolipotoxic hepatic responses and evaluating candidate compounds in a defined in vitro setting.