Synthetic liver fibrotic niche extracts achieve in vitro hepatoblasts phenotype enhancement and expansion

hESCs-derived Organoids Achieve Liver Zonation Features through LSEC Modulation

Liver zonation, essential for diverse physiological functions, is lacking in existing organoid models, hindering their ability to recapitulate liver development and pathogenesis. Addressing this gap, this work explores the feasibility of achieving zonated organoid by co-culturing human embryonic stem cells (hESCs) derived hepatocytes (HEP) with hESCs derived liver sinusoidal endothelial cells (LSECs) exhibiting characteristics of either the liver lobule's pericentral (PC) or periportal (PP) regions. Introducing zonated LSECs with variable WNT2 signaling subtly regulate hepatocyte zonation, resulting in noticeable metabolic function changes. Considering the lipid metabolism variations in PC and PP organoids, this work constructs biomimetic zonated metabolic dysfunction-associated steatotic liver disease (MASLD) organoids and revealed that glucagon-like peptide-1 receptor agonist (GLP-1RA) directly target LSECs, indicating potential therapeutic mechanisms of GLP-1RA in MAFLD alleviation. This study highlights the crucial role of non-parenchymal cells in organoids for recapitulating niche heterogeneity, offering further insights for drug discovery and in vitro modeling of organ heterogeneity.

Synthetic hydrogels support robust and reproducible cardiomyocyte differentiation

Cardiomyocyte manufacturing from human pluripotent stem cells is limited by the variability of differentiation efficiencies, partly attributed to the widespread use of the tumor-derived substrate Matrigel. Here, we describe a screening approach to identify fully-defined synthetic PEG hydrogels that support iPSC-derived cardiac progenitor cell (iPSC-CPC) adhesion, survival, and differentiation into iPSC-derived cardiomyocytes (iPSC-CMs). Our PEG hydrogels supported superior iPSC-CM differentiation efficiency, with a 24% increase in cTnT expression, and greater reproducibility when compared to cells cultured on Matrigel. By combining our 5-level, 3-variable full factorial screening approach with multi-variate analysis, we showed that all substrate variables manipulated here (adhesion ligand type/concentration, stiffness) had a significant influence on iPSC-CPC confluency and that iPSC-CM differentiation was significantly influenced by adhesion ligands. These results highlight the benefit of synthetic, tunable cell culture substrates and multi-variate screening studies to identify substrate formulations for a targeted cell behavior.

Engineered Platforms for Maturing Pluripotent Stem Cell-Derived Liver Cells for Disease Modeling

Several liver diseases (eg, hepatitis B/C viruses, alcoholic/nonalcoholic fatty liver, malaria, monogenic diseases, and drug-induced liver injury) significantly impact global mortality and morbidity. Species-specific differences in liver functions limit the use of animals to fully elucidate/predict human outcomes; therefore, in vitro human liver models are used for basic and translational research to complement animal studies. However, primary human liver cells are in short supply and display donor-to-donor variability in viability/quality. In contrast, human hepatocyte-like cells (HLCs) differentiated from induced pluripotent stem cells and embryonic stem cells are a near infinite cell resource that retains the patient/donor's genetic background; however, conventional protocols yield immature phenotypes. HLC maturation can be significantly improved using advanced techniques, such as protein micropatterning to precisely control cell-cell interactions, controlled sized spheroids, organoids with multiple cell types and layers, 3-dimensional bioprinting to spatially control cell populations, microfluidic devices for automated nutrient exchange and to induce liver zonation via soluble factor gradients, and synthetic biology to genetically modify the HLCs to accelerate and enhance maturation. Here, we present design features and characterization for representative advanced HLC maturation platforms and then discuss HLC use for modeling various liver diseases. Lastly, we discuss desirable advances to move this field forward. We anticipate that with continued advances in this space, pluripotent stem cell-derived liver models will provide human-relevant data much earlier in preclinical drug development and reduce animal usage, help elucidate liver disease mechanisms for the discovery of efficacious and safe therapeutics, and be useful as cell-based therapies for patients suffering from end-stage liver failure.