PubMed HealthSearch

SEARCH · PubMed Health

Results for “mesoderm”

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.

16 recordsLinked to original sources

Brachyury expression levels predict lineage potential and axis-forming ability of in vitro-derived neuromesodermal progenitors.

Neuromesodermal progenitors (NMPs) produce the spinal cord and musculoskeleton in the elongating anterior-posterior axis. In vivo, NMPs possess dual potency, coinciding with regions co-expressing SOX2 and Brachyury (TBXT). In vitro, SOX2/TBXT co-expressing cells can be produced from pluripotent cells and, like their in vivo counterparts, can produce neural tube and somitic mesoderm. However, the functional characteristics of in vitro SOX2/TBXT co-expressing cells remain unclear, confounding comparisons with in vivo data. To address this, we developed a dual Sox2/Tbxt reporter mouse ESC line. SOX2/TBXT reporter-positive cells emerge in vitro from pluripotent populations with dynamics that mirror their appearance in the embryo. Purified SOX2/TBXT co-expressing populations can differentiate towards neurectoderm or mesoderm, including lateral mesoderm upon BMP stimulation. In gastruloids, quantitative live imaging shows that WNT or NOTCH inhibition rapidly leads to downregulation of TBXT expression and diminished axial extension. We show that clonally plated SOX2/TBXT co-expressing cells are bipotent NMPs that can also self-propagate. By combining clonal analysis with mathematical inference, we identify two thresholds of TBXT and/or SOX2 expression, switching clonal output from neural- to mesoderm-biased, and from mesoderm-biased to mesoderm-specified. Image analysis of embryonic NMPs supports a model whereby SOX2 and TBXT independently influence neuromesodermal differentiation. Thus, this Sox2/Tbxt double reporter cell line highlights unsuspected heterogeneity in NMPs, and together with image analysis of embryonic SOX2/TBXT levels, challenges the assumption that neuromesodermal fate choice is primarily governed by mutual antagonism between SOX2/TBXT.

Animals

Endogenous tagging of the TBXT (Brachyury) gene with 2A-EGFP in BJNhem19 human embryonic stem cells using CRISPR-Cas9 genome editing.

Brachyury (TBXT) is a T-box transcription factor essential for directing human embryonic stem cells (hESCs) toward mesodermal lineage specification. Here, we report the generation of a Brachyury/TBXT-2A-EGFP knock-in reporter line in the BJNhem19 hESC line using CRISPR/Cas9-mediated homology-directed repair. Accurate integration of the reporter cassette was confirmed by DNA sequencing and validated by the comparison of EGFP expression to endogenous TBXT gene expression following directed mesodermal differentiation. This reporter line provides a tractable fluorescence-based platform for real-time monitoring of mesodermal commitment, which will help in high-content screening of differentiation protocols.

Journal Article

Glycolytic activity instructs germ layer proportions through regulation of Nodal and Wnt signaling.

Metabolic pathways can influence cell fate decisions, yet their regulative role during embryonic development remains poorly understood. Here, we demonstrate an instructive role of glycolytic activity in regulating signaling pathways involved in mesoderm and endoderm specification. Using a mouse embryonic stem cell (mESC)-based in vitro model for gastrulation, we found that glycolysis inhibition increases ectodermal cell fates at the expense of mesodermal and endodermal lineages. We demonstrate that this relationship is dose dependent, enabling metabolic control of germ layer proportions through exogenous glucose levels. We further show that glycolysis acts as an upstream regulator of Nodal and Wnt signaling and that its influence on cell fate specification can be decoupled from its effects on growth. Finally, we confirm the generality of our findings using a human gastrulation model. Our work underscores the dependence of signaling pathways on metabolic conditions and provides mechanistic insight into the nutritional regulation of cell fate decision-making.

Glycolysis

Dual-patterned pluripotent stem cells self-organize into a human embryo model with extended anterior-posterior patterning.

Human gastruloids are a powerful class of stem cell-derived models that recapitulate key features of early embryonic development, including symmetry breaking and the emergence of three germ layers1-3. However, they lack anterior embryonic structures and coordinated axial organization4-6. To address this limitation, we pre-patterned human pluripotent stem cells (hPSCs) by exposing them to either anterior (FGF2) or posterior (CHIR99021 [CHIR] & retinoic acid [RA]) cues. Upon mixing, these dual-patterned hPSCs interacted and self-organized into elongated structures with both anterior and posterior features-which we term anterior-posterior (AP) human gastruloids. Anteriorly pre-treated cells robustly intercalated into posteriorly pre-treated cells, collectively giving rise to a continuum of neural tissues-including a brain-like domain, a neural tube-like structure, and neuro-mesodermal progenitors (NMPs)-with segmented somites arrayed bilaterally. Single cell RNA sequencing (scRNA-seq) revealed that human AP gastruloids contain cell types resembling the midbrain-hindbrain boundary (MHB), regionalized hindbrain structures (i .e. rhombomeres 1-8), regionalized neural crest (i.e. cranial, vagal, trunk)7,8 and head mesoderm. Transcriptomic comparisons to primate embryos revealed that human AP gastruloids most closely resemble Carnegie stage 11 (CS11) embryos. While they lack a notochord and full dorsal-ventral polarity, human AP gastruloids recapitulate key spatial and temporal features of early neurulation and somitogenesis. Perturbation of folic acid metabolism or rho-associated kinase (ROCK) signaling induced spinal cord defects, phenocopying aspects of spina bifida and other neural tube defects, highlighting this model's potential for studying congenital disorders9. AP gastruloids may serve as a simple, robust, scalable platform for modeling coordinated human AP body axis development. More broadly, our results suggest that controlled interactions between differentially prepatterned progenitors can initiate self-organization of complex body axis features. The "pattern-and-mix" strategy may serve as a generalizable framework for assembling spatially organized stem cell models of mammalian development.

Journal Article

Systematic differences in protein stability underlie species-specific developmental tempo.

Human embryonic development proceeds more slowly than in mice. The segmentation clock offers a tractable model for studying species-specific developmental tempo, as its oscillation period in human induced presomitic mesoderm (iPSM) cells is approximately twice that of mouse. While the core clock gene HES7 exhibits slower protein degradation in human cells, it remains unclear whether such cross-species differences in protein stability reflect a general principle. Here, we perform a dynamic stable isotope labeling of amino acids in cell culture (SILAC)-based proteomic analysis of ∼5,000 proteins in human and mouse iPSM, and we uncover a broad trend of slower protein degradation in human cells, regardless of subcellular localization or degradation pathways. Moreover, inhibition of glycolysis in mouse iPSM partially phenocopies the human protein stability profile, and modulation of protein stability alters the tempo of both the segmentation clock and cellular differentiation. Our findings establish protein stability, with systematic differences across species, as a key mediator linking metabolism to developmental tempo.

Animals

Ectomesenchymal identity emerges via relief of Twist1 transcript destabilisation.

During vertebrate development, a subset of cranial neural crest cells (CNCCs) termed 'ectomesenchyme' differentiates into cell types canonically associated with the mesoderm (cartilage, bone and muscle). While the molecular decisions that guide CNCCs toward ectomesenchymal identity remain incompletely understood, the transcription factor Twist1 plays a central role. Here, we show that while Twist1 transcripts accumulate in late migratory CNCCs as cells enter the pharyngeal arch environment, a Twist1 enhancer within Hdac9 is active in the neural tube and CNCCs. We reconcile the temporal discrepancy between enhancer activity and transcript accumulation by showing that the Twist1 3' UTR from multiple vertebrate species (but not the non-vertebrate chordate Ciona intestinalis) destabilises transcripts in the ectoderm via a conserved AU-Rich Element. Together, these findings reveal a vertebrate-specific, two-tiered regulatory mechanism that uncouples enhancer activity from transcript accumulation, gating the onset of Twist1 expression and the acquisition of ectomesenchymal identity in vertebrate CNCCs.

Animals

Teratoma Formation and Genomic Profiling Using Multi-Omics Approaches.

Teratoma formation is the gold standard assay for evaluating the developmental pluripotency of human and mouse embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). Following subcutaneous injection into immunodeficient mice, pluripotent stem cells spontaneously differentiate into derivatives representing all three embryonic germ layers-ectoderm, mesoderm, and endoderm. Beyond serving as a functional assay for pluripotency, teratomas provide a unique three-dimensional model system for studying early human development and lineage specification in vivo. This chapter describes comprehensive protocols for teratoma formation in immunodeficient mice, tissue processing for multiple downstream genomic applications, and multi-omics profiling approaches. We detail methods for embryonic stem cell culture, teratoma generation via subcutaneous injection, tissue dissection and processing for chromatin immunoprecipitation followed by sequencing (ChIP-Seq), RNA sequencing (RNA-Seq), single-cell multiome profiling combining chromatin accessibility (ATAC-Seq) and gene expression (scRNA-Seq), and histological analysis using hematoxylin and eosin (H&E) staining. Additionally, we provide bioinformatics workflows for analyzing the resulting genomic datasets to characterize the epigenetic and transcriptional landscapes of teratoma-derived tissues. These methods enable comprehensive molecular characterization of developmental processes and provide valuable resources for stem cell biologists studying pluripotency, differentiation, and early embryonic development.

Teratoma

OscillomeR infers ultradian oscillations and targets of the Hes family.

The Hes family, basic-helix-loop-helix transcription factors and downstream effectors of Notch signaling, regulate the fate choices of pancreatic progenitors, muscle stem cells, neuronal progenitors, and presomitic mesoderm cells. Bioluminescence imaging (BLI) has revealed ultradian oscillatory dynamics of Hes-family members Hes1, Hes5, and Hes7. However, identifying which of the Hes target genes also oscillate remains challenging due to the time-consuming and costly nature of tracking individual target genes using BLI. Here, we propose OscillomeR, a computational framework that reconstructs ultradian oscillations from RNA-sequencing data to identify oscillatory target genes at high throughput. OscillomeR predicts thousands of oscillatory genes in synchronized or unsynchronized cell types, identifying both known and novel Hes-family targets. It also captures the dynamic rewiring of gene-regulatory networks during cell differentiation. Overall, OscillomeR is an effective tool for elucidating the functions of oscillatory transcription factors at the genomic scale.

Hes family

Temporal multiomics gene expression data of human embryonic stem cell-derived cardiomyocyte differentiation.

Human embryonic stem cells (hESCs) serve as a valuable in vitro model for studying early human developmental processes due to their ability to differentiate into all three germ layers. Here, we present a comprehensive multi-omics dataset generated by differentiating hESCs into cardiomyocytes via the mesodermal lineage, collecting samples at 10 distinct time points. We measured mRNA levels by mRNA sequencing (mRNA-seq), translation levels by ribosome profiling (Ribo-seq), and protein levels by quantitative mass spectrometry-based proteomics. Technical validation confirmed high quality and reproducibility across all datasets, with strong correlations between replicates. This extensive dataset provides critical insights into the complex regulatory mechanisms of cardiomyocyte differentiation and serves as a valuable resource for the research community, aiding in the exploration of mammalian development and gene regulation.

Humans

MitoScribe single-cell molecular recorder logs graded signaling dynamics into mitochondrial DNA.

Genetically encoded DNA recorders convert transient biological events into stable genomic mutations, offering a means to reconstruct past cellular states. However, current approaches to log historical events by modifying genomic DNA have limited capacity to record the magnitude of biological signals within individual cells. Here, we introduce MitoScribe, a mitochondrial DNA (mtDNA)-based recording platform that uses mtDNA base editors (DdCBEs) to write graded biological signals into mtDNA as neutral, single-nucleotide substitutions at a defined site. Taking advantage of the hundreds to thousands of mitochondrial genome copies per cell, we demonstrate MitoScribe enables reproducible, highly sensitive, non-destructive, durable, and high-throughput measurements of molecular signals, including hypoxia, NF-κB activity, BMP and Wnt signaling. We show multiple modes of operation, including multiplexed recordings of two independent signals, and coincidence detection of temporally overlapping signals. Coupling MitoScribe with single-cell RNA sequencing and mitochondrial transcript enrichment, we further reconstruct signaling dynamics at the single-cell transcriptome level. Applying this approach during the directed differentiation of human induced pluripotent stem cells (iPSCs) toward mesoderm, we show that early heterogeneity in response to a differentiation cue predicts the later cell state. Together, MitoScribe provides a scalable platform for high-resolution molecular recording in complex cellular contexts.

Journal Article

Transcriptional profiling of Hutchinson-Gilford Progeria patients identifies primary target pathways of progerin.

Hutchinson Gilford Progeria Syndrome (HGPS) is an ultra-rare pediatric premature aging disorder. The disease is caused by a point mutation in the LMNA gene leading to the production of the dominant-negative progerin isoform of the nuclear envelope protein lamin A. Disease severity and progression amongst the population of ~140 known patients is variable. Most of the mechanistic insights into the disease have come from studies using cellular or mouse models of HGPS. To probe the clinical relevance of previously implicated cellular pathways and to address the extent of gene expression heterogeneity between patients, we have performed transcriptomic analysis of a comprehensive set of HGPS patients. We find misexpression of several cellular pathways across the patient population, particularly of multiple signaling pathways as well as the Unfolded Protein Response (UPR) and mesodermal cell fate specification. Variability amongst individual patients was limited, with misregulation of the major pathways observed in most patients. Comparing the transcriptome of patients with an inducible HGPS cell model, we distinguished immediate-early cellular response pathways from secondary adaptive pathways and identified mTORC1, the UPR, UV response, apoptosis and TNFα signaling via NF-κB as primary targets of the disease-causing progerin protein.

Hutchinson-Gilford Progeria Syndrome

Pediatric sarcomas: challenges and opportunities.

Pediatric sarcomas are a heterogeneous group of rare mesodermal malignancies. These cancers, which affect children from infancy through adolescence and young adulthood, are in general challenging to treat with currently available therapies. Biologically, many are characterized by quiet genomes, fusion oncoproteins, immune "cold" microenvironments, and vast epigenetic deregulation that contributes to diverse and complex mechanistic drivers. Multifaceted advancements in research strategies, including high-throughput screening, new model systems, surfaceome profiling, and study of oncogenic fusion condensates have led to new opportunities for understanding the biology of pediatric sarcomas. To continue to make progress for these difficult to treat cancers, it will be critical to continue to improve access to bioinformatic data, approach patient care using innovative clinical trial frameworks, and foster interdisciplinary partnerships among medicinal chemists, scientists, clinicians, advocates, and industry partners.

Humans

Swimming Upstream to Understand Congenital Anomalies of the Kidney and Urinary Tract: Zebrafish Models for Developmental Biology, Disease Mechanisms, and Functional Interpretation of Genetic Variation.

Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of pediatric chronic kidney disease (CKD) and comprise a heterogeneous group of developmental disorders with a substantial genetic contribution. Advances in next-generation sequencing have facilitated the identification of numerous candidate genes and rare variants associated with CAKUT. However, establishing causality and defining the biological functions of implicated genes remain major challenges. Functional validation is therefore essential to bridge the gap between gene discovery and mechanistic understanding, enabling the interpretation of genetic variation within the context of kidney development and disease. The zebrafish (Danio rerio) has emerged as a powerful in vivo model for studying renal development and interrogating the function of CAKUT-associated genes. Its utility stems from a high degree of genetic and developmental conservation with humans, conserved nephrogenic pathways, optical transparency during embryogenesis, and the relative ease of genetic manipulation. In this review, we provide an overview of zebrafish kidney development within the broader context of vertebrate nephrogenesis, highlighting the key genetic programs governing intermediate mesoderm specification, nephron segmentation, and pronephric morphogenesis. We then systematically examine CAKUT-associated genes that have been modeled in zebrafish, focusing on studies that have linked genetic perturbations to renal development and structural phenotypes. Finally, we discuss the strengths and limitations of zebrafish models for functional genomics and variant interpretation and consider their emerging role in bridging genetic discovery with mechanistic insights into CAKUT pathogenesis.

Animals

Combined effects of urine exposure and cryopreservation on sperm quality: an in vitro study of retrograde ejaculation.

Sperm quality influences fertility and offspring health through both genomic inheritance and epigenetic inheritance. Thus, for use in clinical-assisted reproductive technology (ART), spermatozoa must have optimal genomic and epigenetic structures. In patients with retrograde ejaculation, spermatozoa are usually recovered from urine and then cryopreserved for ART. However, the effects of urine exposure and subsequent freeze-thaw cycles on sperm quality remain unclear. This is particularly true for epigenetic changes and their underlying mechanisms. In this study, we examined how different durations of urine exposure (10 min and 40 min) followed by freeze-thaw cycles affected sperm motility, DNA integrity, and methylation levels of imprinting genes (H19-imprinted maternally expressed transcript [ H19 ], mesoderm-specific transcript [ MEST ], and the transposable element Alu [ Alu ]). As the duration of urine exposure increased, sperm motility (median [interquartile range]) decreased from 48.0% (39.0%-52.5%) to 1.0% (1.0%-5.0%), the DNA fragmentation index (DFI; median [interquartile range]) increased from 12.0% (9.3%-19.9%) to 23.5% (13.9%-33.9%), the MEST methylation level (mean ± standard deviation [s.d.]) increased from 3.8% ± 1.5% to 11.5 ± 1.2%, and the H19 methylation level (mean ± s.d.) decreased from 86.9% ± 0.9% to 82.1% ± 0.5%. The freeze-thaw process further reduced sperm motility, while the DFI and methylation levels of MEST and H19 did not significantly change. The Alu methylation level remained stable. These findings demonstrate that urine exposure affects sperm motility, DNA integrity, and methylation levels of some imprinting genes. These effects intensify over time. In contrast, the freeze-thaw process impacts only sperm motility. In clinical practice, minimizing exposure to urine might improve sperm quality.

Humans

Fetal-like reversion in the regenerating intestine is regulated by mesenchymal asporin.

Mesenchymal cells and the extracellular matrix (ECM) support epithelium during homeostasis and regeneration. However, the role of the mesenchyme in epithelial conversion into a fetal-like regenerative state after damage is not known. We modeled epithelial regeneration by culturing intestinal epithelium on decellularized small intestinal scaffolds (iECM) and identify asporin (Aspn), an ECM-bound proteoglycan, as a critical mediator of epithelial fetal-like reprogramming. After damage, transient increase in Aspn expression by the pericryptal fibroblasts induces epithelial transforming growth factor β (TGF-β)-signaling via CD44 and promotes timely epithelial reprogramming. Temporal control of Aspn is lost in old mice, and after damage, the persistently high level of Aspn stagnates epithelium in the regenerative state. Increase in Wnt signaling can resolve the stagnated regenerative program of the old epithelium, promoting restoration of tissue function. In summary, we establish a platform for modeling epithelial injury responses ex vivo and show that the mesenchymal Aspn-producing niche modulates tissue repair by regulating epithelial fetal-like reprogramming.

Animals

A molecular map of mesenchymal tumors.

BACKGROUND: Bone and soft tissue tumors represent a diverse group of neoplasms thought to derive from cells of the mesenchyme or neural crest. Histological diagnosis is challenging due to the poor or heterogenous differentiation of many tumors, resulting in uncertainty over prognosis and appropriate therapy. RESULTS: We have undertaken a broad and comprehensive study of the gene expression profile of 96 tumors with representatives of all mesenchymal tissues, including several problem diagnostic groups. Using machine learning methods adapted to this problem we identify molecular fingerprints for most tumors, which are pathognomonic (decisive) and biologically revealing. CONCLUSION: We demonstrate the utility of gene expression profiles and machine learning for a complex clinical problem, and identify putative origins for certain mesenchymal tumors.

Gene Expression Profiling