Spatiotemporal imaging and analysis of mouse and human liver bud morphogenesis

Abstract

Background: The process of liver organogenesis has served as a paradigm for organ formation. However, there remains a lack of understanding regarding early mouse and human liver bud morphogenesis and early liver volumetric growth. Elucidating dynamic changes in liver volumes is critical for understanding organ development, implementing toxicological studies, and for modeling hPSC-derived liver organoid growth. New visualization, analysis, and experimental techniques are desperately needed.Results: Here, we combine observational data with digital resources, new 3D imaging approaches, retrospective analysis of liver volume data, mathematical modeling, and experiments with hPSC-derived liver organoids. Mouse and human liver organogenesis, characterized by exponential growth, demonstrate distinct spatial features and growth curves over time, which we mathematically modeled using Gompertz models. Visualization of liver-epithelial and septum transversum mesenchyme (STM) interactions suggests extended interactions, which together with new spatial features may be responsible for extensive exponential growth. These STM interactions are modeled with a novel in vitro human pluripotent stem cell (hPSC)-derived hepatic organoid system that exhibits cell migration. Conclusions: Our methods enhance our understanding of liver organogenesis, with new 3D visualization, analysis, mathematical modeling, and in vitro

Linking collective migration/growth to differentiation boosts global shaping of the transcriptome and exhibits a grasshopper effect for driving maturation

“…We have obtained several novel findings that push forward the field of LO, including novel 3-step protocol and medium formulation, a new cell population that has not previously has been induced or isolated, a simple but effective in vivo model, extensive knowledge and analysis of the E9.5 niche and transcriptome, and a molecular mechanism involved in hPSC liver organoid growth/CCM. In terms of accuracy of modeling the LO, our simple in vivo model transplant model demonstrates exponential growth at approximately the rate of in vivo liver growth 10 and our in vitro model demonstrates rapid ALB activation, collective cell migration, and growth, function of immature HBs, and establishment of the hepatic nuclear GRN (FOXA1, FOXA2, FOXA3, HNF1α, HNF1ß, HNF4α, HNF6, HEX, TBX3, and PROX1) 15 . Our 3-step culture platform be used as an initial step in hPSC-HEP differentiation, and our study will serve as a resource for the LD-MESC.…”

“…A) 3D images of the E9.0 Liver Diverticulum (LD) (right) (adopted from 10 ). LD (green) is shown to be surrounded by mesodermal-derivatives (MES) (red).…”

“…Importantly, both the teratoma and the DE:HFF condition were mixed samples that contained RNA of other contaminating cell types, and that likely the hepatic-specific RNA values were indeed higher. We determined the in vivo growth rate by estimating cell size initially and after 4 weeks, and compared to in vivo growth for 4 weeks 10 we observed a 40-fold increase in volume compared to in vivo eLO. Nonetheless, the data suggests that the hLD-MESC model exhibits hypoxic exponential growth, morphogenesis and CCM within MES tissue, and rapid ALB transcription, events that occur in the murine LD-MESC ( Fig.…”

“…Early LO (eLO) is a stage during which early growth, differentiation, and migration are coordinated. In eLO, the E9.0 liver diverticulum (LD), an out pocketing of tissue with only ~1500 cells, amazingly, expands by ~10 2 -fold by E10 and by 10 3 -fold by E11.5 10 . The LD transitions to the E10.5 liver bud (LB) bearing the microarchitecture for forming primitive sinusoids 11 .…”

Liver organoids: From fabrication to application in liver diseases

“…After the liver organoid is generated, its performance can usually be assessed in vitro by morphological tests ( Broutier et al, 2016 ; Aloia et al, 2019 ; Ogoke et al, 2022 ), functional tests ( Akbari et al, 2019 ), such as P450 activity assays, and single-cell sequencing ( Elbadawy et al, 2020 ). Compared to morphological and functional tests, single-cell sequencing is more reflective of the similarity between the organoid and the primary liver.…”