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Biology subjects

Dan, Y. Y.

Publications and source records attributed to Dan, Y. Y..

3 recordsLinked to original sources

A chemically defined and xeno-free hydrogel system for regenerative medicine.

Biofabricated scaffolds facilitate bona fide cellular interactions, cell type specification, and the formation of three-dimensional tissue architecture from human pluripotent stem cells (hPSCs). However, xenogenic biomaterials are poorly defined, and synthetic biomaterials remain underdeveloped and understudied, hindering regulatory approval for clinical use and preventing the translation of lab-grown therapies. Here, we describe a protein screen-based hydrogel system biofabricated from clinical-grade human components. We show that "Alphagel", a base hydrogel comprising human embryonic matrices, supports the trilineage differentiation of hPSCs into neural, cardiac, and liver tissue. Alphagel is also shown to be biocompatible and biodegradable in vivo. Further, upon adding select proteins from maturing human foetal liver to Alphagel, we show that the resulting hydrogel (termed "Hepatogel") enhances the differentiation of hPSC-derived hepatocytes (H-iHeps) compared with Matrigel. Importantly, when injected into mice livers, Hepatogel significantly improves the retention of H-iHeps compared to standard aqueous cell injections. Altogether, our results provide proof of concept that customisable and organ-specific hydrogel systems are a valuable tool for developing clinically translatable therapies for regenerative medicine and tissue engineering.

bioengineering↗

Single-cell and spatial atlas of steatotic liver-related hepatocellular carcinoma

Steatotic liver disease-related hepatocellular carcinoma (SLD-HCC) poses significant challenges in liver cancer management. Our current study investigates the tumor microenvironment (TME) of SLD-HCC using single-cell transcriptomic, proteomic and spatial transcriptomic analyses. We identified altered immune-related and lipid metabolism pathways, particularly in regulatory T cells (Tregs) and cancer-associated fibroblasts (CAFs) within the SLD-HCC microenvironment, suggesting distinct cellular adaptations to a high-fat TME and general immunosuppression. Cytometry by time-of-flight revealed a cold and immunosuppressive TME depleted with CD8+ T cells and enriched with Tregs, while spatial transcriptomics uncovered a unique spatial architecture with Treg/CAF clusters specifically located at the tumor margins in SLD-HCC. Crucially, we identified Treg-CAF interactions as a key mediator associated with lack of response to immunotherapy in SLD-HCC. Our findings highlight the intricate immune dynamics of SLD-HCC, indicating potential therapeutic targets to counteract immune evasion and restore anti-tumor immunity in SLD-HCC. HighlightsO_LIThe TME of SLD-HCC exhibits altered immune and lipid pathways C_LIO_LIImmunosuppressive SLD-HCC TME is depleted with CD8+ T cells and enriched with Tregs C_LIO_LISLD-HCC has a unique spatial architecture with Treg-CAF clusters at tumor margins C_LIO_LITreg-CAF interaction via TNFSF14-TNFRSF14 axis mediates immunotherapy resistance C_LI

immunology↗

Endothelial-immune crosstalk contributes to vasculopathy in non-alcoholic fatty liver disease

The top cause of mortality in patients with non-alcoholic fatty liver disease (NAFLD) is cardiovascular complications. However, the mechanisms of NAFLD-associated vasculopathy remain understudied. We developed blood outgrowth endothelial cell (BOEC) models from NAFLD and healthy subjects. NAFLD BOECs exhibited global transcriptional upregulation of chemokine hallmarks and human leukocyte antigens. In mouse models of diet-induced NAFLD, we further confirmed enhanced endothelial expressions of CXCL12 in the aortas and liver vasculatures. To elucidate endothelial-immune crosstalk, we performed immunoprofiling by single-cell analysis, uncovering T cell intensification and potentially T-helper type 1 inflammation in NAFLD patients. Functionally, interference of the CXCL12-CXCR4 axis by small molecule AMD3100 selectively modulated the chemotaxis of patient-derived CD4+ T cells and natural killer cells towards NAFLD BOECs, restoring endothelial barrier integrity. Clinically, we detected three folds more circulating damaged endothelial cells in NAFLD patients than healthy controls. Our work provides insights for modulation of interactions with effector immune subsets to mitigate endothelial injury in NAFLD.

cell biology↗