On the adhesion-cohesion balance and oxygen consumption characteristics of liver organoids

• Published in: PloS one 2017-03, Vol.12 (3), p.e0173206
• Main Authors: Mattei, Giorgio, Magliaro, Chiara, Giusti, Serena, Ramachandran, Sarada Devi, Heinz, Stefan, Braspenning, Joris, Ahluwalia, Arti
• Format: Article
• Language: English
• Subjects: Adhesion; Adhesives; Algorithms; Biology and Life Sciences; Biomarkers; Cell Adhesion; Cell culture; Cell Culture Techniques; Cohesion; Concentration gradient; Core loss; Culture Media; Endothelial cells; Extracellular Matrix - chemistry; Extracellular Matrix - metabolism; Gels - chemistry; Growth factors; Health aspects; Hepatocytes; Hepatocytes - metabolism; Hepatotoxicity; Humans; Hypoxia; Liver; Liver - metabolism; Mechanical properties; Media (culture); Medicine and Health Sciences; Mesenchyme; Metabolism; Models, Biological; Organ transplantation; Organoids; Oxygen; Oxygen Consumption; Oxygen consumption (Metabolism); Oxygen depletion; Physical Sciences; Physicochemical properties; Research and Analysis Methods; Rodents; Self assembly; Spheroids; Stem cells; Stiffness; Studies; Substrates; Tissue engineering; Tissue Scaffolds - chemistry
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0173206

Liver organoids (LOs) are of interest in tissue replacement, hepatotoxicity and pathophysiological studies. However, it is still unclear what triggers LO self-assembly and what the optimal environment is for their culture. Hypothesizing that LO formation occurs as a result of a fine balance between cell-substrate adhesion and cell-cell cohesion, we used 3 cell types (hepatocytes, liver sinusoidal endothelial cells and mesenchymal stem cells) to investigate LO self-assembly on different substrates keeping the culture parameters (e.g. culture media, cell types/number) and substrate stiffness constant. As cellular spheroids may suffer from oxygen depletion in the core, we also sought to identify the optimal culture conditions for LOs in order to guarantee an adequate supply of oxygen during proliferation and differentiation. The oxygen consumption characteristics of LOs were measured using an O2 sensor and used to model the O2 concentration gradient in the organoids. We show that no LO formation occurs on highly adhesive hepatic extra-cellular matrix-based substrates, suggesting that cellular aggregation requires an optimal trade-off between the adhesiveness of a substrate and the cohesive forces between cells and that this balance is modulated by substrate mechanics. Thus, in addition to substrate stiffness, physicochemical properties, which are also critical for cell adhesion, play a role in LO self-assembly.