Publications by authors named "Takashi Aoi"

Multi-cellular organoids are self-assembly aggregates that mimic biological functions and developmental processes of many tissue types in vitro. They are widely employed for disease modeling and functional studies. Hypothalamus-pituitary organoids can be generated through differentiation induction from pluripotent stem cells.

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Parkinson's disease (PD) is a common neurodegenerative disorder characterized by dopaminergic neuron loss and α-synuclein aggregation. While some familial cases result from single-gene mutations, most are sporadic, involving complex genetic and environmental interactions. Among PD risk loci identified through genome-wide association studies, MCCC1 encodes a mitochondrial enzyme essential for leucine catabolism; however, the causal variant remains unclear.

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Organelle targeting is a useful approach in drug development for cancer therapy. Peptide amphiphiles are good candidates for targeting specific organelles because they can be engineered into a wide range of molecular structures, enabling customization for specific functional needs. We have developed a peptide amphiphile, C16-(EY)3, that can respond to tyrosine kinase activity and undergo phosphorylation inside cancer cells.

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Late-onset hypogonadism (LOH) syndrome is characterized by age-related testosterone deficiency and negatively affects the quality of life of older men. A promising therapeutic approach for LOH syndrome is transplantation of testosterone-producing Leydig-like cells (LLCs) derived from human induced pluripotent stem cells (hiPSCs). However, previous studies have encountered obstacles, such as limited cell longevity, insufficient testosterone production, and inefficiency of differentiation.

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Cancer stem cells (CSCs) have been implicated as critical mediators in the progression, chemoresistance and metastatic capabilities of diverse malignancies, including osteosarcoma (OS). The authors have succeeded in generating CSC‑like cells (MG‑OKS) from the OS cell line MG‑63 by transducing defined factors. A significant increase in small proline‑rich protein 1A (SPRR1A) expression, a cross‑linked envelope protein in keratinocytes, was observed in MG‑OKS cells.

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Introduction: In human placental development, the trophectoderm (TE) appears in blastocysts on day 5 post-fertilization and develops after implantation into three types of trophoblast lineages: cytotrophoblast (CT), syncytiotrophoblast (ST), and extravillous trophoblast (EVT). CDX2/Cdx2 is expressed in the TE, and Cdx2 expression is upregulated by knockdown of Foxo1 in mouse ESCs. However, the significance of FOXO1 in trophoblast lineage differentiation during the early developmental period remains unclear.

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Article Synopsis
  • - Xeroderma pigmentosum (XP) is a genetic condition leading to extreme sensitivity to sunlight, causing skin damage and increasing the risk of skin cancer due to improper DNA repair, particularly in patients with XP group A (XP-A).
  • - In this study, researchers created melanocytes (skin pigment cells) from induced pluripotent stem cells (iPSCs) derived from XP-A fibroblasts, and compared their responses to UV irradiation with those of healthy control iPSC-derived melanocytes.
  • - The results showed that XP-A melanocytes had less ability to repair DNA and exhibited significant changes in gene expression after UV exposure, notably in cytokine and apoptotic pathways, suggesting they are crucial for understanding the disease and
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This study highlights the novel potential of molecular aggregates as inhibitors of a disease-related protein. Enzyme inhibitors have been studied and developed as molecularly targeted drugs and have been applied for cancer, autoimmune diseases, and infections. In many cases, enzyme inhibitors that are used for therapeutic applications interact directly with enzymes in a molecule-to-molecule manner.

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With the progression of regenerative medicine and cell therapy, the importance of cryopreservation techniques for cultured cells continues to rise. Traditional cryoprotectants, such as dimethyl sulfoxide and glycerol, are effective in cryopreserving suspended cells, but they do not demonstrate sufficient efficacy for two-dimensional (2D)-cultured cells. In the past decade, small molecules and polymers have been studied as cryoprotectants.

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Human pluripotent stem cells, such as human embryonic stem cells and human induced pluripotent stem cells, are used in basic research and various applied fields, including drug discovery and regenerative medicine. Stem cell technologies have developed rapidly in recent years, and the supply of culture materials has improved. This has facilitated the culture of human pluripotent stem cells and has enabled an increasing number of researchers and bioengineers to access this technology.

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  • Overactivated microglia are linked to sepsis-associated encephalopathy (SAE), while the role of T cells, particularly γδT cells, remains unclear.
  • In a sepsis mouse model, increased anxious behavior was observed 10 days after sepsis induction, alongside a significant rise in IL-17 mRNA and γδT cell counts in the brain at 8 days post-induction.
  • Treatment with antibodies to deplete γδT cells and IL-17A improved anxious behavior and reduced microglial activation, indicating that IL-17-producing γδT cells contribute to worsening psychological effects in septic mice.
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Background: Our study and several studies have reported that in some cancers, including pancreatic ductal adenocarcinoma (PDAC), the expression of squamous lineage markers, such as esophagus-tissue-specific genes, correlated with a poor prognosis. However, the mechanism by which the acquisition of squamous lineage phenotypes leads to a poor prognosis remains unclear. We previously reported that retinoic acid signaling via retinoic acid receptor γ (RARγ signaling) determines the differentiation lineage into the esophageal squamous epithelium.

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For a long time, ex vivo-expanded peripheral-blood-derived γδT cell (PBγδT)-based immunotherapy has been attractive, and clinical trials have been undertaken. However, the difficulty in expanding cytotoxic γδT cells to an adequate number has been a major limitation to the efficacy of treatment in most cases. We successfully re-generated γδT cells from γδT cell-derived human induced pluripotent stem cells (iPSCs).

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Background: The chorioallantoic membrane (CAM) assay is a well-established technique to evaluate tumor invasion and angiogenesis and may overcome the shortcoming of the patient-derived xenograft (PDX) mouse model. Currently, few reports have described lung cancer invasion and angiogenesis in the CAM assay. We therefore used the CAM assay in the evaluation of lung cancer.

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Cell-selective killing using molecular self-assemblies is an emerging concept for cancer therapy. Reported molecular self-assemblies are triggered by hydrolysis of well-designed molecules inside or outside cancer cells. This hydrolysis can occur in cancer and normal cells because of the abundance of water in living systems.

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Article Synopsis
  • * Recent research indicates that slow-cycling cells (SCCs) may significantly contribute to tumor growth, chemoresistance, and the likelihood of recurrence in ES.
  • * This study successfully used a CFSE labeling system to identify and analyze SCCs in ES, finding unique properties and gene expressions that could lead to better understanding and treatment targets for the disease.
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Background & Aims: The Notch signaling pathway is an important pathway in the adult pancreas and in pancreatic ductal adenocarcinoma (PDAC), with hairy and enhancer of split-1 (HES1) as the core molecule in this pathway. However, the roles of HES1 in the adult pancreas and PDAC formation remain controversial.

Methods: We used genetically engineered dual-recombinase mouse models for inducing Hes1 deletion under various conditions.

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Objectives: Small proline-rich protein 1A (SPRR1A) is recognized as a squamous differentiation marker but is also upregulated in some non-squamous cancers. However, its expression in pancreatic ductal adenocarcinoma (PDAC) has not been investigated. This study elucidated the expression of SPRR1A in PDAC and its effect on the prognosis and malignant behavior of PDAC.

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Intestinal metaplasia is related to gastric carcinogenesis. Previous studies have suggested the important role of CDX2 in intestinal metaplasia, and several reports have shown that the overexpression of CDX2 in mouse gastric mucosa caused intestinal metaplasia. However, no study has examined the induction of intestinal metaplasia using human gastric mucosa.

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Human gastric development has not been well studied. The generation of human pluripotent stem cell-derived gastric organoids (hGOs) comprising gastric marker-expressing epithelium without an apparent smooth muscle (SM) structure has been reported. We modified previously reported protocols to generate hGOs with muscularis mucosa (MM) from hiPSCs.

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Fukuyama congenital muscular dystrophy (FCMD) is a severe, intractable genetic disease that affects the skeletal muscle, eyes, and brain and is attributed to a defect in alpha dystroglycan (αDG) -mannosyl glycosylation. We previously established disease models of FCMD; however, they did not fully recapitulate the phenotypes observed in human patients. In this study, we generated induced pluripotent stem cells (iPSCs) from a human FCMD patient and differentiated these cells into three-dimensional brain organoids and skeletal muscle.

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Late-onset hypogonadism (LOH) syndrome, due to a partial lack of testosterone, decreases the quality of life of older men. Testosterone is mainly secreted by Leydig cells in the testes. Leydig cell transplantation is expected to be a promising alternative to conventional testosterone replacement therapy for LOH syndrome.

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Self-assembly of synthetic molecules has been drawing broad attention as a novel emerging approach in drug discovery. Here, we report selective cell death induced by a novel peptide amphiphile that self-assembles to form entangled nanofibers (hydrogel) based on intracellular pH (pH). We found that a palmitoylated hexapeptide (C-VVAEEE) formed a hydrogel below pH 7.

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Background: Cancer stem cells (CSCs) are considered to be responsible for tumor initiation, formation, and poor prognosis of cancer patients. However, the rarity of CSCs in clinical samples makes it difficult to elucidate characteristics of CSCs, especially in osteosarcoma (OS). The aim of this study is to verify whether it is possible to generate CSC-like cells by transducing defined factors into an OS cell line.

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