Dr. Botao Gao is a Research Professor, deputy director of Laboratory of biomedical materials at the Institute of biomedical engineering, Guangdong Academy of Sciences. He obtained MSc from the School of dentistry at Peking University in 2011 and PhD from the Department of Materials Engineering, the University of Tokyo in 2015. He then joined Prof. Teruo Okano’s lab at Tokyo women’s medical university for postdoctoral research and got assistant professor position in 2019. He joined Guangdong Academy of Sciences in 2020 as the Young Talents Program Researcher of the Guangdong Academy of Sciences. Dr. Gao’s research interests focus on 3D liver disease model, cell-derived matrix and cell sheet-based tissue engineering.
Production of induced human ballooned hepatocytes in a cell sheet-based three dimensional model
Lack of appropriate translational preclinical in vitro human models hinders the drug development for nonalcoholic steatohepatitis (NASH). As far as we know, hepatocellular ballooning which is a key histologic feature in the determination of the diagnosis of NASH has been seldom reported in in vitro models. In this study, a cell sheet-based three-dimensional (3D) model with cocultured primary human hepatocytes and normal human dermal fibroblasts was engineered to produce induced human ballooned hepatocytes (iBHs) (Figure 1). Characteristic findings of hepatocellular ballooning in human NASH, such as enlargement of hepatocytes (2.3 times larger than normal, P < 0.01), loss of the cytoplasmic keratin, appearance of Mallory-Denk bodies (MDB) and abundant fat droplets accumulation were observed in the iBHs after only a few days culture. Additionally, ultrastructural characteristic findings of NASH, including enlarged mitochondria with crystalline inclusions, dilated endoplasmic reticulum (ER) as well as MDBs formation were also observed. Furthermore, pathophysiological features of human NASH, such as increased secretion of sonic hedgehog ligands, decreased cytochrome P450 enzyme activities (CYP1A2, CYP3A4) and myofibroblast activation were found. Increased gene expression of ER stress markers, including DDIT3 and XBP1 was also found in this model, suggesting ER stress might be a possible reason for the formation of iBHs. In addition, obeticholic acid, which is a potential drug for NASH, dose dependently reversed iBH in this model. As far as we know, this is the first study reporting in vitro production of iBHs, which show similar histological, ultrastructural and pathophysiological features to human NASH. This model may facilitate study of hepatocellular ballooning and provide new insights for building in vitro NASH model.