Biology subjects

J.W. van der Laan, L.

Publications and source records attributed to J.W. van der Laan, L..

4 recordsLinked to original sources

bioRxiv2025

Integrated mesenchymal and extracellular cues drive bioengineered liver tissue formation and function

Human liver tissue engineering holds promise for creating physiological in vitro models but faces challenges replicating liver complexity. In the present study, we created bioengineered liver tissues (BLTs) utilizing three different cell types; human intrahepatic cholangiocyte organoids (ICOs), hepatic stellate cells (HSCs), and mesenchymal stromal cells (MSCs). Co-culturing with HSCs and MSCs accelerated growth and spontaneous fusion, resulting in complex liver-like tissue structures. In a dynamic suspension culture, BLTs had a more compact morphology and higher expression of hepatic markers, including ALB, CYP3A4, and MRP2. We further showed that animal-derived Matrigel can be replaced by a synthetic polyisocyanide (PIC)-based hydrogel for BLTs. Importantly, PIC-based hydrogel further promoted the maturation of BLTs assessed by parameters as intracellular protein levels, morphological analysis, and metabolic activity. Transcriptomic analyses revealed mechanisms underlying tissue formation and function. To conclude, our strategy yields functional liver tissues suitable for disease modelling, drug screening, and toxicity tests, and forms an important basis for future development of larger liver tissues for in vivo transplantation.

bioengineering↗

bioRxiv2025

Tissue scarring provides a biomechanical framework to promote mammalian bile duct regeneration through the activation of integrin-SRC/FAK signalling.

Following chronic injury, the adult mammalian bile duct regenerates by forming new branches, essentially replumbing the ductular system to overcome blockages and breaks. To regenerate effectively, biliary epithelial cells (BECs) receive a range of pro-mitogenic signals from myofibroblasts, which concurrently deposit a collagen-rich scar around the duct as it regrows. Despite epithelial regeneration and scarring occurring side-by-side, whether the deposition of scar tissue regulates ductular regeneration per se remains unclear. By inducing ductular fibrosis and regeneration in vivo, we show that the formation of collagen-I-rich scars around regenerating ducts changes the local biomechanical properties of these tissues, promoting the growth of ducts. Critically, this changing structural landscape is perceived by a spatially restricted population of biliary epithelial cells which forms a "leading-tip" of integrin-2-high cells. This leading-tip undergoes partial-EMT-type reprogramming, allowing it to become migratory and coordinate ductular regeneration. We show that this process is directly driven through an integrin-2-SRC/FAK signalling axis; thereby connecting epithelial regeneration directly to the changing fibrotic environment in chronic ductular disease. HighlightsO_LIChronic liver disease results in the formation of stiff, collagen scars around ducts. C_LIO_LINew ducts acquire high levels of integrin-2 which is spatially localised to a "leading-tip", which loses epithelial features. C_LIO_LIIntegrin-2{beta}1-SRC/FAK signalling regulates ductular migration by linking changes in the bio-structural composition of the liver with ductular cells. C_LI

cell biology↗

bioRxiv2025

Integration of lymphatic vasculature to a human lymph node-on-chip enhances physiological immune properties

To study systemic human innate and adaptive immune responses in detail, competent in vitro lymph node (LN) models with LN stromal cells (LNSCs) are required to recapitulate the physiological microenvironment. The multicellular organisation of LNs possesses a challenge for designing such microphysiological systems (MPS), particularly with the structural complexity of LNs and the lymphatic vasculature. Here, we established an organotypic LN model with integrated lymphatics in an organ-on-chip (OoC) platform containing a printed sacrificial structure, and studied the influence of a perfused lymphatic endothelial cell (LEC)-lined channel on the LN-on-chip microenvironment. Upon one-week of culture under lymphatic flow, LECs lined the tubular structure forming a lymphatic vessel through the LN model, and stable metabolic conditions within the LN-on-chip were confirmed. Interestingly, LECs in the LN-on-chip displayed the phenotype found in human LNs with upregulation of LEC-specific LN markers, such as atypical chemokine receptor 4 (ACKR4). The presence of the LEC-lined perfused vessel in the LN-on-chip resulted in the increase of native immune cells, most notably B cells, and the secretion of survival and migratory signals, namely interleukin-7 (IL-7) and CC motif chemokine ligand 21 (CCL21). Likewise, LECs promoted the abundance of immune cell clusters closer to the vessel. As such, these features represent an enhanced physiological microenvironment to allow for immune cell migration and interactions for efficient LN functioning. This approach paves the way for LN integration into multi-OoC (MOC) platforms to investigate immunological crosstalk between tissue-derived factors, immune cell trafficking and organ-specific adaptive immune responses.

bioengineering↗

bioRxiv2023

Integrative omics analysis reveals gene regulatory mechanisms distinguishing organoid-derived hepatocytes from primary human hepatocytes

Background and AimsHepatic organoid cultures are considered a powerful model system to study liver development and diseases in vitro. However, hepatocyte-like cells differentiated from such organoids remain immature compared to primary human hepatocytes. Therefore, a comprehensive understanding of differences in gene regulatory mechanisms between primary human hepatocytes and hepatic organoids is essential to obtain functional hepatocyte-like cells in vitro for fundamental and therapeutic applications. MethodsWe obtained primary human hepatocytes at high purity from all zones of the liver lobule using an optimized two-step perfusion protocol. We captured the single-cell transcriptome and chromatin accessibility landscape using scRNA-seq and ATAC-seq, respectively. We identified key transcription factors and compared the gene regulatory mechanisms in primary human hepatocytes and (un)differentiated intrahepatic cholangiocyte organoids. Using siRNA-mediated perturbations, we showed the functional relevance of an organoid-enriched transcription factor during in vitro differentiation of hepatocyte-like cells. ResultsOur integrative omics analysis revealed that Activator Protein 1 (AP-1) family members cooperate with hepatocyte-specific transcription factors, including HNF4A, in maintaining cellular functionality of mature human hepatocytes. Comparative analysis identified distinct transcription factor sets specifically active in human hepatocytes and organoids. Amongst these ELF3 is unique to intrahepatic cholangiocyte organoids and its expression level negatively correlate with expression of hepatic marker genes. Functional analysis of ELF3 furthermore revealed that ELF3 depletion optimizes the formation of hepatocyte-like cells from intrahepatic cholangiocyte organoids. ConclusionsCollectively, our integrative analysis provides insights into the transcriptional regulatory networks of human hepatocytes and hepatic organoids, thereby informing future strategies for better establishment of urgently-needed hepatic model systems in vitro.

molecular biology↗