PubMed HealthSearch

SEARCH · PubMed Health

Results for “stem cell model of development”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources

The development of experimental brain tumours a sequential light and electron microscope study of the subependymal plate. II. Microtumours.

Pregnant BD-IX rats were given a single intraperitoneal injection of 30 mg of N-ethyl-N-nitrosourea (ENU) per kg of body weight on the 15th day of gestation. The offspring were killed at fortnightly intervals between 2 and 20 weeks of age. The subependymal plate region adjacent to the lateral ventricles was examined by light and electron microscopy to study the early stages in the development of brain tumours. Microtumours, composed of subependymal plate cells, glioblasts and various glial cells at different stages of maturation, were found in 16-, 18-, and 20-week-old rats. The most common site for microtumours was the angle of the lateral ventricles between the corpus callosum and caudate nucleus; others were located at the lateral aspect of the ventricles. It is suggested that most, if not all, cerebral gliomas originate from the undifferentiated cells of the subependymal plate: these mitotically active stem cells provide a susceptible target for the carcinogenic stimulus. The morphology of the gliomas developed is determined by the diverging processes of differentiation and anaplasia resulting in a pleomorphic cell population. The relevance of this experimental model to the pathogenesis of human gliomas is discussed.

Animals

A rabbit used as a model for testing hematopoietic tissue transplants.

Allogenic transplantations of bone marrow or spleen cells were carried out on rabbits treated with cyclophosphamide. About 50% of the recipients developed chimerism of peripheral blood cells. Chimerism was a passing phenomenon prevailing from 14 to 180 days after grafting. A phenomenon indicating that not all cell lines develop after transplantation from the donor stem cells, was observed. This phenomenon has been called "restricted chimerism". The GvH reaction was of a chronic type. Relative spleen weights were significantly increased in animals receiving the spleen cell grafts, but not in animals receiving bone marrow grafts. A direct positive erythrocyte Coombs test was found in almost all graft recipients. In addition cytotoxic autoantibodies against lymphocytes were present in sera of about 20% of the recipients.

Animals

Histogenesis of symmetrical 1,2-dimethylhydrazine-induced neoplasms of the colon in the mouse.

CF-1 female adult mice were given weekly sc injections of 20 mg symmetrical 1,2-dimethylhydrazine (DMH)-2HCl/kg body weight and killed at various intervals after commencement of the injection. [3H]thymidine (TdR) was given before the animals were killed. The histogenesis of colon neoplasms was investigated by means of autoradiographs prepared from sections of Epon-embedded descending colon, which were stained with periodic acid-Schiff reaction and iron hematoxylin. By 9 weeks after initiation of DMH treatment, the distal 5 cm of the colon became enlarged, the mucosa thickened, and the crypts were elongated and hyperplastic. In the hyperplastic crypts, the number of proliferating cells increased, but the distribution of these cells followed a previously discussed slow cut-off model of Cairnie et al. as for the normal crypts. Differentiation and transformation of epithelial cells occurred, but somewhat aberrantly. Hyperplasia of the crypts occurred diffusely, but neoplastic lesions that began to appear by 9 weeks after the intiial treatment were isolated. An isolated crypt from which a neoplasm developed was first repopulated by what appeared to be altered, undifferentiated "stem" cells. These cells did not differentiate, continued to divide, and eventually upon migration accumulated in the upper part of the crypts, where an earliest identifiable neoplastic lesion was observed. Once such a lesion was formed, it expanded in various directions, depending on the local environments, and formed a polypoid or discoid lesion. The biologic behavior of the neoplasm seemed to be determined by the downward progression of its leading edge. When it penetrated the muscularis mucosae, the neoplasm became highly invasive. In the murine model, the invasive adenocarcinomas were observed by 26 weeks after commencement of DMH treatment.

Adenocarcinoma

Recent developments in understanding the pathogenesis of aplastic anemia.

Bone marrow failure in aplastic anemia (AA) could result from abnormalities of hematopoietic stem cells, abnormal control of hematopoiesis, or abnormalities of the hematopoietic environment. Bone marrow transplantation, in vitro marrow culture techniques, and studies in animal models of marrow failure have provided insights on the possible pathogenetic mechanisms underlying AA. Studies in man and in murine models suggest that most often AA results from injuries to hematopoietic stem cells. Despite the intriguing report of abnormal regulatory cells in congenitally anemic mice, instances of marrow failure due to defective humoral or cellular control of hematopoiesis have not been identified in man. In vitro studies employing allogeneic marrow targets have suggested that immune suppression of hematopoiesis may occasionally mediate AA in man. Marrow failure due to abnormalities of the hematopoietic microenvironment has been suggested by experience with bone marrow transplantation, but no direct study of this possibility has been reported. Based on available evidence, it seems likely that AA will prove to be many diseases that share common clinical and morphologic features.

Anemia, Aplastic

hPSC models in cancer mechanisms and therapeutic discovery.

Despite major advances in cancer genomics and immunotherapy, the field remains limited by experimental models that fail to faithfully recapitulate human tumor initiation, genetic context, and immune-tumor interactions. Traditional animal and immortalized cell models often lack predictive power for therapeutic response and toxicity. Recent advances in human pluripotent stem cell (hPSC) technology have transformed this landscape, enabling the generation of patient-specific cancer models, multicellular organoids and assembloids, and scalable immune effector cells. These platforms now permit mechanistic dissection of tumorigenesis, reconstruction of human tumor microenvironments, and development of off-the-shelf immunotherapies. This review will synthesize these emerging findings, define key technological and biological gaps, and outline future directions for integrating hPSC-based modeling into precision oncology and translational cancer research.

cancer immunotherapy

Effect of methylcellulose injection on murine hematopoiesis.

This study was designed to determine the effect of methylcellulose (MC)-induced reticuloendothelial (RE) hypertrophy on neutrophils and hematopoietic stem cells and to contrast its overall hematologic effect in the mouse to the more frequently studied rat model. Mice were given MC 3 times/wk and studies were done at 2, 3, and 4 wk, with maximal hematologic change by 2 wk. A stable, but incompletely compensated hemolytic anemia developed which was accompanied by a significant shift of erythropoiesis from marrow to spleen. Thrombocytopenia developed as did neutrophilia, accompanied by an increased number of marrow neutrophil precursors. Extramedullary hematopoiesis was observed in the liver. The number of cells forming spleen colonies in irradiated recipients increased in the spleen but not in marrow. The number of cells producing granulocyte and macrophage colonies in semisolid media increased in spleen and marrow. Splenectomized mice, treated with MC, developed changes very similar to intact mice. Thus, it appears that all three major hematopoietic lines may be destroyed by the MC-hypertrophied RE system. The mouse differs from the rat in its hematologic response to MC by destroying cells in organs other than the spleen, by increasing neutrophil production, by developing hepatic hematopoiesis, and by developing all changes more rapidly.

Anemia, Hemolytic

Regeneration of intact spleen in a heterotropic site in splenectomized mice.

The regeneration of intact spleens implanted in the sacrospinal areas of splenectomized mice was studied by light microscopy. The weight of the implanted tissue was not fully regenerated 50 days after implantation. The pattern of embryonic development of the spleen was investigated and the histologic appearance of the implant 46 days after implantation resembled that of normal spleen. The appearance of primitive myelopoietic stem in cells in the early phases of regeneration makes this an attractive model in which to study the biologic effects of tumour viruses.

Animals

An Integrated Proteomics and Genomics Approach to Identify Essential Protein Kinases During Human Trophoblast Development.

In the developing human placenta, three subtypes of trophoblast cells, cytotrophoblasts (CTBs), extravillous trophoblasts (EVTs), and syncytiotrophoblasts (STBs), mediate critical functions essential for a successful pregnancy. CTBs constitute the stem/progenitor compartment and differentiate into STBs and EVTs within the floating and anchoring villi, respectively. STBs establish the maternal-fetal exchange interface and secrete human chorionic gonadotropin (hCG), a hormone vital for the maintenance of early pregnancy. EVTs anchor the maternal endometrium and invade the uterine tissue to remodel maternal cells, supporting implantation and progression of pregnancy. In this study, we used human trophoblast stem cells (hTSCs) as a model system and performed quantitative, label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS) to profile the proteome and phosphoproteome in TSC stem state (analogous to undifferentiated CTBs) and following their differentiation to STBs and EVTs. Through a multiomics approach, we integrated our proteomics data with global gene expression profiles to correlate cell-type specific gene and protein expression during human trophoblast development. We also identified global phosphoproteome and analyzed kinases that are specifically active in hTSC stem state, as well as in differentiated STBs and EVTs. We experimentally validated specific kinases, such as BUB1B, PAK6, PKYMT1, and TNIK, that are essential for maintaining the hTSC stem-state. Additionally, atypical protein kinase C isoforms PKCζ are essential for STB development, whereas PTK2B, SRC, TRIO, and LYN are important for EVT development. Our findings highlight key kinases uniquely required for specific stages of trophoblast development during human placentation and suggest that pharmacological inhibition of these kinases could negatively impact the placentation process during pregnancy.

Humans

Identification of Potential Therapeutic Agents for Type I Interferonopathy Using iPSC-Based Disease Modeling.

PURPOSE: Type I interferonopathy encompasses disorders marked by systemic inflammation and neurological involvement, arising from genetic mutations that result in the upregulation of type I IFN signaling through various mechanisms. Currently, therapeutic options are limited, and no standard therapy exists. This study aims to develop a strategy for identifying new therapeutic targets for type I interferonopathy using induced pluripotent stem cells (iPSCs). METHODS: The IFIH1 R779H variant was introduced into iPSCs through genome editing. RNA sequencing of iPSC-derived dendritic cells (DCs) was performed, and differentially expressed genes (DEGs) were identified. IFN-α secretion, reactive oxygen species (ROS), and mitochondrial oxygen consumption rate (OCR) were analyzed in iPSC-derived DCs. An in silico prediction of compounds binding to the OAS-like domain was conducted. Candidate compounds were evaluated for their ability to inhibit IFN secretion from IFIH1 R779H-mutated iPSC-derived DCs. RESULTS: Transcriptome analysis indicated upregulation of the IFN-related and metabolic pathways. IFIH1 R779H-mutated iPSC-derived DCs exhibited increased OCR and ROS generation, and blocking mitochondrial metabolism significantly reduced excessive IFN-α secretion. Among the DEGs, PML was upregulated, and targeting this gene with arsenic trioxide (ATO), a PML antagonist, suppressed IFN-α secretion from IFIH1 R779H-mutated iPSC-derived DCs. Additionally, bisantrene, phthalylsulfathiazole and ganaplacide were predicted to bind to the RNA binding groove of OAS-like domain of human OASL in silico, effectively inhibiting IFN-α secretion from IFIH1 R779H-mutated DCs. CONCLUSION: Our iPSC-based disease modeling and drug investigation approach provides a robust platform for validating the efficacy and toxicity of candidate therapeutic agents for rare and intractable human diseases such as type I interferonopathy.

Humans

Generation of a hiPSC from a patient with an ITSN1-associated neurodevelopmental disorder spectrum carrying biallelic c.2893_2894insA (p.Tyr965Ter) genetic variant.

De novo truncating variants in ITSN1 are implicated in neurodevelopment disorders spectrum, however, biallelic variants in ITSN1 have not been previously identified. Here we present a hiPSC line generated from a patient dermal fibroblast carrying biallelic variant, c.2893_2894insA (p.Tyr965Ter). The hiPSC line expresses core stemness markers, mycoplasma free with normal karyotype and demonstrate trilineage differentiation capacity. The hiPSC line provides a valuable in-vitro model system to investigate its role in early brain development and neurodevelopmental disorders.

Humans

Identification of Glioblastoma Cell Surface Proteins and Assessment of Their Expression Across Patient-Derived Stem-Like Cell Cultures.

Glioblastoma (GBM) is the most common primary brain cancer in adults and remains fatal, with a median survival of a few months. There is an urgent need to develop novel therapeutic strategies against this aggressive malignancy. Modern cancer research increasingly focuses on personalized therapies tailored toward unique molecular features of each tumor or patient. In this context, cell surface proteins (CSPs) represent an attractive class of therapeutic targets due to their accessibility and central roles in physiological and pathological processes, making them among the most targeted proteins in current drug development. In this study, promising CSPs were identified through an untargeted proteomics approach using high-resolution mass spectrometry on patient-derived GBM stem-like cell (GSC) cultures, complemented by RNA-seq data and computational database analyses. From this primary discovery, five CSPs, namely PTK7, PTPRZ1, OSMR, CSPG4, and IGDCC4, were selected for detailed investigation. A targeted UHPLC-multiple reaction monitoring (MRM) method was developed and optimized to assess their expression and evaluate their abundance variations across different GSC cultures and cell passage levels. Beyond confirming these CSPs as potential therapeutic targets in GBM, our study demonstrates the value of three-dimensional GSC cultures as robust models for biomarker research and target assessment.

Humans

Notions about human stem cells.

From an analysis of the known red cell and granulocytic cell turnover rates in the peripheral blood, absolute bone marrow cellularity of man, mitotic index of human marrow, tritiated thymidine labeling index of human marrow, the proportional distribution of the different cell types in the bone marrow of man and the measured DNA synthesis time of differentiated cell lines in human bone marrow, the flux of stem cells into the differentiated compartment has been calculated. By assuming that the same fraction of committed stem cells of man and mouse are in DNA synthesis, the number of cells in DNA synthesis and the size of the stem cell compartments have been calculated. The calculation gives an abundance of stem cells in human marrow that is much larger than that estimated by in vitro culture techniques. On the basis of the calculations, it is hypothesized that the pool of cells preceding the cytologically differentiated pools may consist of self replicating committed stem cells and differentiated cells undergoing amplification that have not developed cytologic markers characteristics of differentiated cells.

Bone Marrow

Establishing a national pediatric stem cell transplantation registry in Iran addressing implementation and data quality challenges.

The Iranian Pediatric Hematopoietic Stem Cell Transplantation Registry (IPED-HSCT) was established to enhance data collection, improve patient outcomes, and support clinical research in pediatric hematopoietic stem cell transplantation. This study aimed to assess the feasibility and reliability of implementing a standardized registry in pediatric settings. A community-based participatory study was conducted across three pediatric HSCT centers in Iran. The registry development involved a multi-phase approach, including pilot testing and the implementation of a web-based system. Data were collected from fifty pediatric patients who underwent HSCT for both malignant and non-malignant conditions, with a focus on data completeness and user satisfaction. Statistical analyses were performed using IBM SPSS Statistics. The registry achieved a data completeness rate exceeding 90%, with a participant demographic of 31 males (62%) and 19 females (38%). Rigorous quality control measures and real-time validation rules were implemented, enhancing data reliability. User feedback indicated high satisfaction with the platform's design and training sessions. Challenges included variations in long-term follow-up data collection across centers. The IPED-HSCT Registry demonstrates that establishing a robust pediatric HSCT registry is feasible even in resource-limited settings. Its innovative features offer a scalable model for similar initiatives in developing countries. Future research should focus on ensuring long-term sustainability and fostering international collaborations to improve pediatric HSCT outcomes globally. not applicable.

Humans

Rapid and reversible epigenome editing by endogenous chromatin regulators.

Understanding the causal link between epigenetic marks and gene regulation remains a central question in chromatin biology. To edit the epigenome we developed the FIRE-Cas9 system for rapid and reversible recruitment of endogenous chromatin regulators to specific genomic loci. We enhanced the dCas9-MS2 anchor for genome targeting with Fkbp/Frb dimerizing fusion proteins to allow chemical-induced proximity of a desired chromatin regulator. We find that mSWI/SNF (BAF) complex recruitment is sufficient to oppose Polycomb within minutes, leading to activation of bivalent gene transcription in mouse embryonic stem cells. Furthermore, Hp1/Suv39h1 heterochromatin complex recruitment to active promoters deposits H3K9me3 domains, resulting in gene silencing that can be reversed upon washout of the chemical dimerizer. This inducible recruitment strategy provides precise kinetic information to model epigenetic memory and plasticity. It is broadly applicable to mechanistic studies of chromatin in mammalian cells and is particularly suited to the analysis of endogenous multi-subunit chromatin regulator complexes.Understanding the link between epigenetic marks and gene regulation requires the development of new tools to directly manipulate chromatin. Here the authors demonstrate a Cas9-based system to recruit chromatin remodelers to loci of interest, allowing rapid, reversible manipulation of epigenetic states.

CRISPR-Cas Systems

A probabilistic generative model for quantification of DNA modifications enables analysis of demethylation pathways.

We present a generative model, Lux, to quantify DNA methylation modifications from any combination of bisulfite sequencing approaches, including reduced, oxidative, TET-assisted, chemical-modification assisted, and methylase-assisted bisulfite sequencing data. Lux models all cytosine modifications (C, 5mC, 5hmC, 5fC, and 5caC) simultaneously together with experimental parameters, including bisulfite conversion and oxidation efficiencies, as well as various chemical labeling and protection steps. We show that Lux improves the quantification and comparison of cytosine modification levels and that Lux can process any oxidized methylcytosine sequencing data sets to quantify all cytosine modifications. Analysis of targeted data from Tet2-knockdown embryonic stem cells and T cells during development demonstrates DNA modification quantification at unprecedented detail, quantifies active demethylation pathways and reveals 5hmC localization in putative regulatory regions.

5-Methylcytosine

A mouse organoid platform for modeling cerebral cortex development and cis-regulatory evolution in vitro.

Natural selection has shaped the gene regulatory networks that orchestrate cortical development, leading to structural and functional variation across mammals, but the molecular and cellular mechanisms underpinning these changes have only begun to be characterized. Here, we develop a reproducible protocol for cerebral cortex organoid generation from mouse epiblast stem cells (EpiSCs), which recapitulates the timing and cellular differentiation programs of the embryonic cortex. We generated cortical organoids from F1 hybrid EpiSCs derived from crosses between laboratory mice (C57BL/6J) and four wild-derived inbred strains spanning ∼1 M years of evolutionary divergence to comprehensively map cis-acting transcriptional regulatory variation across developing cortical cell types, using single-cell RNA sequencing (scRNA-seq). We identify hundreds of genes that exhibit dynamic allelic imbalances, providing the first insight into the developmental mechanisms underpinning changes in cortical structure and function between subspecies. These experimental methods and cellular resources represent a powerful platform for investigating gene regulation in the developing cerebral cortex.

Organoids

Development and characterization of triazole-based WDR5 inhibitors for the treatment of glioblastoma.

Glioblastoma (GBM) cancer stem cells (CSCs) contribute to tumor recurrence, treatment resistance, and dismal clinical outcomes. Genetic and pharmacological evidence suggests that the nuclear scaffolding protein WD-repeat containing protein 5 (WDR5) is a therapeutic vulnerability of the CSC population. However, previously reported WDR5 inhibitors display low permeability and are unable to penetrate the blood-brain barrier (BBB), limiting their utility in GBM. Herein, we report the structure-guided development of a series of triazole-based WDR5 WIN-site inhibitors designed to increase passive brain penetration. We identified triazole-based WDR5 inhibitors that are potent, passively permeable, and in some cases more brain penetrant than other scaffolds. We phenotypically assessed our WDR5 inhibitors in a panel of patient-derived CSC models and uncovered unique WDR5-regulated metabolic genes in GBM. We also evaluated their antiproliferative activity against CSCs both in vitro and in vivo. Finally, to identify potential combination opportunities, we screened a 2,100-compound chemical probe library and identified that the ATAD2 inhibitor BAY-850 synergizes with WDR5 inhibitors to enhance CSC killing. Our work diversifies the chemical matter targeting WDR5, clarifies the in vitro consequences of WIN-site inhibition in CSCs, and encourages the future development of next-generation WDR5 inhibitors with the potential to achieve in vivo efficacy in the brain.

Humans