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Nature Nov 2020Fibrosis can affect any organ and is responsible for up to 45% of all deaths in the industrialized world. It has long been thought to be relentlessly progressive and... (Review)
Review
Fibrosis can affect any organ and is responsible for up to 45% of all deaths in the industrialized world. It has long been thought to be relentlessly progressive and irreversible, but both preclinical models and clinical trials in various organ systems have shown that fibrosis is a highly dynamic process. This has clear implications for therapeutic interventions that are designed to capitalize on this inherent plasticity. However, despite substantial progress in our understanding of the pathobiology of fibrosis, a translational gap remains between the identification of putative antifibrotic targets and conversion of this knowledge into effective treatments in humans. Here we discuss the transformative experimental strategies that are being leveraged to dissect the key cellular and molecular mechanisms that regulate fibrosis, and the translational approaches that are enabling the emergence of precision medicine-based therapies for patients with fibrosis.
Topics: Cytokines; Fibroblasts; Fibrosis; Gastrointestinal Microbiome; Genome, Human; Humans; Integrins; Macrophages; Mesoderm; Precision Medicine; Single-Cell Analysis; Transforming Growth Factor beta; Translational Research, Biomedical
PubMed: 33239795
DOI: 10.1038/s41586-020-2938-9 -
Nature Jan 2021Kidney fibrosis is the hallmark of chronic kidney disease progression; however, at present no antifibrotic therapies exist. The origin, functional heterogeneity and...
Kidney fibrosis is the hallmark of chronic kidney disease progression; however, at present no antifibrotic therapies exist. The origin, functional heterogeneity and regulation of scar-forming cells that occur during human kidney fibrosis remain poorly understood. Here, using single-cell RNA sequencing, we profiled the transcriptomes of cells from the proximal and non-proximal tubules of healthy and fibrotic human kidneys to map the entire human kidney. This analysis enabled us to map all matrix-producing cells at high resolution, and to identify distinct subpopulations of pericytes and fibroblasts as the main cellular sources of scar-forming myofibroblasts during human kidney fibrosis. We used genetic fate-tracing, time-course single-cell RNA sequencing and ATAC-seq (assay for transposase-accessible chromatin using sequencing) experiments in mice, and spatial transcriptomics in human kidney fibrosis, to shed light on the cellular origins and differentiation of human kidney myofibroblasts and their precursors at high resolution. Finally, we used this strategy to detect potential therapeutic targets, and identified NKD2 as a myofibroblast-specific target in human kidney fibrosis.
Topics: Adaptor Proteins, Signal Transducing; Animals; Calcium-Binding Proteins; Case-Control Studies; Cell Differentiation; Cell Lineage; Extracellular Matrix; Female; Fibroblasts; Fibrosis; Humans; Kidney Tubules; Male; Mesoderm; Mice; Myofibroblasts; Pericytes; RNA-Seq; Receptor, Platelet-Derived Growth Factor alpha; Receptor, Platelet-Derived Growth Factor beta; Renal Insufficiency, Chronic; Single-Cell Analysis; Transcriptome
PubMed: 33176333
DOI: 10.1038/s41586-020-2941-1 -
Nature Communications Jun 2021Fibrotic skin disease represents a major global healthcare burden, characterized by fibroblast hyperproliferation and excessive accumulation of extracellular matrix....
Fibrotic skin disease represents a major global healthcare burden, characterized by fibroblast hyperproliferation and excessive accumulation of extracellular matrix. Fibroblasts are found to be heterogeneous in multiple fibrotic diseases, but fibroblast heterogeneity in fibrotic skin diseases is not well characterized. In this study, we explore fibroblast heterogeneity in keloid, a paradigm of fibrotic skin diseases, by using single-cell RNA-seq. Our results indicate that keloid fibroblasts can be divided into 4 subpopulations: secretory-papillary, secretory-reticular, mesenchymal and pro-inflammatory. Interestingly, the percentage of mesenchymal fibroblast subpopulation is significantly increased in keloid compared to normal scar. Functional studies indicate that mesenchymal fibroblasts are crucial for collagen overexpression in keloid. Increased mesenchymal fibroblast subpopulation is also found in another fibrotic skin disease, scleroderma, suggesting this is a broad mechanism for skin fibrosis. These findings will help us better understand skin fibrotic pathogenesis, and provide potential targets for fibrotic disease therapies.
Topics: Cell Adhesion Molecules; Collagen; Extracellular Matrix; Fibroblasts; Gene Expression Regulation; Gene Ontology; Humans; Keloid; Ligands; Mesoderm; RNA-Seq; Scleroderma, Systemic; Single-Cell Analysis; Skin Diseases
PubMed: 34140509
DOI: 10.1038/s41467-021-24110-y -
The Journal of Clinical Investigation Jul 2023Mesenchymal cells are uniquely located at the interface between the epithelial lining and the stroma, allowing them to act as a signaling hub among diverse cellular... (Review)
Review
Mesenchymal cells are uniquely located at the interface between the epithelial lining and the stroma, allowing them to act as a signaling hub among diverse cellular compartments of the lung. During embryonic and postnatal lung development, mesenchyme-derived signals instruct epithelial budding, branching morphogenesis, and subsequent structural and functional maturation. Later during adult life, the mesenchyme plays divergent roles wherein its balanced activation promotes epithelial repair after injury while its aberrant activation can lead to pathological remodeling and fibrosis that are associated with multiple chronic pulmonary diseases, including bronchopulmonary dysplasia, idiopathic pulmonary fibrosis, and chronic obstructive pulmonary disease. In this Review, we discuss the involvement of the lung mesenchyme in various morphogenic, neomorphogenic, and dysmorphogenic aspects of lung biology and health, with special emphasis on lung fibroblast subsets and smooth muscle cells, intercellular communication, and intrinsic mesenchymal mechanisms that drive such physiological and pathophysiological events throughout development, homeostasis, injury repair, regeneration, and aging.
Topics: Infant, Newborn; Humans; Lung; Pulmonary Disease, Chronic Obstructive; Fibrosis; Regeneration; Mesoderm; Epithelial Cells
PubMed: 37463440
DOI: 10.1172/JCI170498 -
Nature Dec 2022Our understanding of human early development is severely hampered by limited access to embryonic tissues. Due to their close evolutionary relationship with humans,...
Our understanding of human early development is severely hampered by limited access to embryonic tissues. Due to their close evolutionary relationship with humans, nonhuman primates are often used as surrogates to understand human development but currently suffer from a lack of in vivo datasets, especially from gastrulation to early organogenesis during which the major embryonic cell types are dynamically specified. To fill this gap, we collected six Carnegie stage 8-11 cynomolgus monkey (Macaca fascicularis) embryos and performed in-depth transcriptomic analyses of 56,636 single cells. Our analyses show transcriptomic features of major perigastrulation cell types, which help shed light on morphogenetic events including primitive streak development, somitogenesis, gut tube formation, neural tube patterning and neural crest differentiation in primates. In addition, comparative analyses with mouse embryos and human embryoids uncovered conserved and divergent features of perigastrulation development across species-for example, species-specific dependency on Hippo signalling during presomitic mesoderm differentiation-and provide an initial assessment of relevant stem cell models of human early organogenesis. This comprehensive single-cell transcriptome atlas not only fills the knowledge gap in the nonhuman primate research field but also serves as an invaluable resource for understanding human embryogenesis and developmental disorders.
Topics: Animals; Humans; Mice; Gastrulation; Macaca fascicularis; Organogenesis; Single-Cell Analysis; Embryoid Bodies; Gene Expression Profiling; Primitive Streak; Neural Tube; Neural Crest; Hippo Signaling Pathway; Mesoderm; Stem Cells
PubMed: 36517595
DOI: 10.1038/s41586-022-05526-y -
Nature Dec 2019Formation of the three primary germ layers during gastrulation is an essential step in the establishment of the vertebrate body plan and is associated with major...
Formation of the three primary germ layers during gastrulation is an essential step in the establishment of the vertebrate body plan and is associated with major transcriptional changes. Global epigenetic reprogramming accompanies these changes, but the role of the epigenome in regulating early cell-fate choice remains unresolved, and the coordination between different molecular layers is unclear. Here we describe a single-cell multi-omics map of chromatin accessibility, DNA methylation and RNA expression during the onset of gastrulation in mouse embryos. The initial exit from pluripotency coincides with the establishment of a global repressive epigenetic landscape, followed by the emergence of lineage-specific epigenetic patterns during gastrulation. Notably, cells committed to mesoderm and endoderm undergo widespread coordinated epigenetic rearrangements at enhancer marks, driven by ten-eleven translocation (TET)-mediated demethylation and a concomitant increase of accessibility. By contrast, the methylation and accessibility landscape of ectodermal cells is already established in the early epiblast. Hence, regulatory elements associated with each germ layer are either epigenetically primed or remodelled before cell-fate decisions, providing the molecular framework for a hierarchical emergence of the primary germ layers.
Topics: Animals; Cell Differentiation; Cell Lineage; Chromatin; DNA Methylation; Demethylation; Embryoid Bodies; Endoderm; Enhancer Elements, Genetic; Epigenesis, Genetic; Epigenome; Erythropoiesis; Factor Analysis, Statistical; Gastrula; Gastrulation; Gene Expression Regulation, Developmental; Mesoderm; Mice; Pluripotent Stem Cells; RNA; Single-Cell Analysis; Time Factors; Zinc Fingers
PubMed: 31827285
DOI: 10.1038/s41586-019-1825-8 -
Cell Stem Cell Sep 2022A hallmark of primate postimplantation embryogenesis is the specification of extraembryonic mesoderm (EXM) before gastrulation, in contrast to rodents where this tissue...
A hallmark of primate postimplantation embryogenesis is the specification of extraembryonic mesoderm (EXM) before gastrulation, in contrast to rodents where this tissue is formed only after gastrulation. Here, we discover that naive human pluripotent stem cells (hPSCs) are competent to differentiate into EXM cells (EXMCs). EXMCs are specified by inhibition of Nodal signaling and GSK3B, are maintained by mTOR and BMP4 signaling activity, and their transcriptome and epigenome closely resemble that of human and monkey embryo EXM. EXMCs are mesenchymal, can arise from an epiblast intermediate, and are capable of self-renewal. Thus, EXMCs arising via primate-specific specification between implantation and gastrulation can be modeled in vitro. We also find that most of the rare off-target cells within human blastoids formed by triple inhibition (Kagawa et al., 2021) correspond to EXMCs. Our study impacts our ability to model and study the molecular mechanisms of early human embryogenesis and related defects.
Topics: Animals; Cell Differentiation; Embryo, Mammalian; Germ Layers; Humans; Mesoderm; Pluripotent Stem Cells; Primates
PubMed: 36055191
DOI: 10.1016/j.stem.2022.08.001 -
Science (New York, N.Y.) Jul 2021Oocytes mature in a specialized fluid-filled sac, the ovarian follicle, which provides signals needed for meiosis and germ cell growth. Methods have been developed to...
Oocytes mature in a specialized fluid-filled sac, the ovarian follicle, which provides signals needed for meiosis and germ cell growth. Methods have been developed to generate functional oocytes from pluripotent stem cell-derived primordial germ cell-like cells (PGCLCs) when placed in culture with embryonic ovarian somatic cells. In this study, we developed culture conditions to recreate the stepwise differentiation process from pluripotent cells to fetal ovarian somatic cell-like cells (FOSLCs). When FOSLCs were aggregated with PGCLCs derived from mouse embryonic stem cells, the PGCLCs entered meiosis to generate functional oocytes capable of fertilization and development to live offspring. Generating functional mouse oocytes in a reconstituted ovarian environment provides a method for in vitro oocyte production and follicle generation for a better understanding of mammalian reproduction.
Topics: Animals; Cell Culture Techniques; Cell Differentiation; Embryonic Development; Female; Fertilization in Vitro; Male; Mesoderm; Mice; Mice, Inbred ICR; Mouse Embryonic Stem Cells; Oocytes; Oogenesis; Ovarian Follicle; RNA-Seq; Steroidogenic Factor 1; Transcriptome
PubMed: 34437124
DOI: 10.1126/science.abe0237 -
Cell Jun 2023The hourglass model describes the convergence of species within the same phylum to a similar body plan during development; however, the molecular mechanisms underlying...
The hourglass model describes the convergence of species within the same phylum to a similar body plan during development; however, the molecular mechanisms underlying this phenomenon in mammals remain poorly described. Here, we compare rabbit and mouse time-resolved differentiation trajectories to revisit this model at single-cell resolution. We modeled gastrulation dynamics using hundreds of embryos sampled between gestation days 6.0 and 8.5 and compared the species using a framework for time-resolved single-cell differentiation-flows analysis. We find convergence toward similar cell-state compositions at E7.5, supported by the quantitatively conserved expression of 76 transcription factors, despite divergence in surrounding trophoblast and hypoblast signaling. However, we observed noticeable changes in specification timing of some lineages and divergence of primordial germ cell programs, which in the rabbit do not activate mesoderm genes. Comparative analysis of temporal differentiation models provides a basis for studying the evolution of gastrulation dynamics across mammals.
Topics: Animals; Rabbits; Mice; Gastrulation; Mesoderm; Cell Differentiation; Mammals; Trophoblasts; Gene Expression Regulation, Developmental
PubMed: 37209682
DOI: 10.1016/j.cell.2023.04.037 -
Cell Feb 2023Using four-dimensional whole-embryo light sheet imaging with improved and accessible computational tools, we longitudinally reconstruct early murine cardiac development...
Using four-dimensional whole-embryo light sheet imaging with improved and accessible computational tools, we longitudinally reconstruct early murine cardiac development at single-cell resolution. Nascent mesoderm progenitors form opposing density and motility gradients, converting the temporal birth sequence of gastrulation into a spatial anterolateral-to-posteromedial arrangement. Migrating precardiac mesoderm does not strictly preserve cellular neighbor relationships, and spatial patterns only become solidified as the cardiac crescent emerges. Progenitors undergo a mesenchymal-to-epithelial transition, with a first heart field (FHF) ridge apposing a motile juxta-cardiac field (JCF). Anchored along the ridge, the FHF epithelium rotates the JCF forward to form the initial heart tube, along with push-pull morphodynamics of the second heart field. In Mesp1 mutants that fail to make a cardiac crescent, mesoderm remains highly motile but directionally incoherent, resulting in density gradient inversion. Our practicable live embryo imaging approach defines spatial origins and behaviors of cardiac progenitors and identifies their unanticipated morphological transitions.
Topics: Mice; Animals; Heart; Cell Differentiation; Morphogenesis; Mesoderm; Embryo, Mammalian; Mammals
PubMed: 36736300
DOI: 10.1016/j.cell.2023.01.001