Biology subjects

Toguchida, J.

Publications and source records attributed to Toguchida, J..

5 recordsLinked to original sources

bioRxiv2025

Modeling the human limb skeletal development using human pluripotent stem cell-derived skeletal assembloid

Despite recent advances in pluripotent stem cell-based approaches to induce skeletal cells, recapitulating human limb skeletal development in terms of structure and longitudinally oriented growth remains an unresolved challenge. Here, we report a method to differentiate human pluripotent stem cells into region-specific skeletal organoids harboring GDF5+PRG4+ interzone/articular chondrocyte progenitors (IZ/ACPs) and SP7+ growth plate chondrocytes (GPCs) via PRRX1+ limb-bud mesenchymal cells. Comparative analysis demonstrated marked similarities of IZ/ACP and GPC organoids to the human embryonic limb, and graft fate and regenerative capacity in vivo were further characterized. We also mimicked the limb skeletal developmental process in a spatially structured manner by vertically positioning two IZ/ACP organoids at both ends of a GPC organoid to generate a human skeletal assembloid. Notably, this human skeletal assembloid recapitulated endochondral ossification with longitudinal skeletal growth upon transplantation. In summary, our study provides a novel research platform for human limb skeletal development and disease.

bioengineering↗

bioRxiv2021

The oncogenic Runx3-Myc axis defines p53-deficient osteosarcomagenesis

Osteosarcoma (OS) in human patients is characterized by genetic alteration of TP53. Osteoprogenitor-specific p53-deleted mice (OS mice) have been widely used to study the process of osteosarcomagenesis. However, the molecular mechanisms responsible for the development of OS upon p53 inactivation remain largely unknown. In this study, we detected prominent RUNX3/Runx3 expression in human and mouse p53-deficient OS. Myc was aberrantly upregulated by Runx3 via mR1, a consensus Runx site in the Myc promoter, in a manner dependent on p53 deficiency. Reduction of the Myc level by disruption of mR1 or Runx3 knockdown decreased the tumorigenicity of p53-deficient OS cells and effectively suppressed OS development in OS mice. Furthermore, Runx inhibitors exerted therapeutic effects on OS mice. Together, these results show that p53 deficiency promotes osteosarcomagenesis in human and mouse by allowing Runx3 to induce oncogenic Myc expression.

cancer biology↗

bioRxiv2020

Human iPSC-derived hypertrophic chondrocytes reveal a mutation-specific unfolded protein response in chondrodysplasias

Chondrodysplasias are hereditary diseases caused by mutations in the components of growth cartilage. Although the unfolded protein response (UPR) has been identified as a key disease mechanism in mouse models, no suitable in vitro system has been reported to analyze the pathology in humans. Here, utilizing human chondrodysplasia-specific iPSCs, we examined the UPR caused by mutations in MATN3 or COL10A1. In growth plate-like structures formed from iPSC-derived sclerotome in vivo, the hypertrophic zone was disrupted, and induced hypertrophic chondrocytes in vitro showed varying levels of ER stress depending on the mutation. Autophagy inducers and chemical chaperones succeeded in reducing ER stress only in some mutants, while transcriptome analysis revealed many mutation-specific changes in genes involved in apoptosis, metabolism, and protein trafficking. In this way, our system has allowed the precise evaluation of the UPR caused by each mutation, opening up new avenues for treatment of individual chondrodysplasia patients.

cell biology↗

bioRxiv2019

Species-specific oscillation periods of human and mouse segmentation clocks are due to cell autonomous differences in biochemical reaction parameters

While the mechanisms of embryonic development are similar between mouse and human, the tempo is in general slower in human. The cause of interspecies differences in developmental time remains a mystery partly due to lack of an appropriate model system1. Since murine and human embryos differ in their sizes, geometries, and nutrients, we use in vitro differentiation of pluripotent stem cells (PSCs) to compare the same type of cells between the species in similar culture conditions. As an example of well-defined developmental time, we focus on the segmentation clock, oscillatory gene expression that regulates the timing of sequential formation of body segments2-4. In this way we recapitulate the murine and human segmentation clocks in vitro, showing that the species-specific oscillation periods are derived from cell autonomous differences in the speeds of biochemical reactions. Presomitic mesoderm (PSM)-like cells induced from murine and human PSCs displayed the oscillatory expression of HES7, the core gene of the segmentation clock5,6, with oscillation periods of 2-3 hours (mouse PSM) and 5-6 hours (human PSM). Swapping HES7 loci between murine and human genomes did not change the oscillation periods dramatically, denying the possibility that interspecies differences in the sequences of HES7 loci might be the cause of the observed period difference. Instead, we found that the biochemical reactions that determine the oscillation period, such as the degradation of HES7 and delays in its expression, are slower in human PSM compared with those in mouse PSM. With the measured biochemical parameters, our mathematical model successfully accounted for the 2-3-fold period difference between mouse and human. We further demonstrate that the concept of slower biochemical reactions in human cells is generalizable to several other genes, as well as to another cell type. These results collectively indicate that differences in the speeds of biochemical reactions between murine and human cells give rise to the interspecies period difference of the segmentation clock and may contribute to other interspecies differences in developmental time.

developmental biology↗

bioRxiv2019

Modeling the Human Segmentation Clock with Pluripotent Stem Cells

Pluripotent stem cells (PSCs) have increasingly been used to model different aspects of embryogenesis and organ formation1. Despite recent advances in the in vitro induction of major mesodermal lineages and mesoderm-derived cell types2,3, experimental model systems that can recapitulate more complex biological features of human mesoderm development and patterning are largely missing. Here, we utilized induced pluripotent stem cells (iPSCs) for the stepwise in vitro induction of presomitic mesoderm (PSM) and its derivatives to model distinct aspects of human somitogenesis. We focused initially on modeling the human segmentation clock, a major biological concept believed to underlie the rhythmic and controlled emergence of somites, which give rise to the segmental pattern of the vertebrate axial skeleton. We succeeded to observe oscillatory expression of core segmentation clock genes, including HES7 and DKK1, and identified novel oscillatory genes in human iPSC-derived PSM. We furthermore determined the period of the human segmentation clock to be around five hours and showed the presence of dynamic traveling wave-like gene expression within in vitro induced human PSM. Utilizing CRISPR/Cas9-based genome editing technology, we then targeted genes, for which mutations in patients with abnormal axial skeletal development such as spondylocostal dysostosis (SCD) (HES7, LFNG and DLL3) or spondylothoracic dysostosis (STD) (MESP2) have been reported. Subsequent analysis of patient-like iPSC knock-out lines as well as patient-derived iPSCs together with their genetically corrected isogenic controls revealed gene-specific alterations in oscillation, synchronization or differentiation properties, validating the overall utility of our model system, to recapitulate not only key features of human somitogenesis but also to provide novel insights into diseases associated with the formation and patterning of the human axial skeleton.

developmental biology↗