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Project description:Colonies of induced pluripotent stem cells (iPSCs) reveal aspects of self-organization even under culture conditions that maintain pluripotent state. To investigate the dynamics of this process under spatial confinement we used either PDMS pillars or micro-contact printing of vitronectin. OCT4, E-cadherin, and NANOG were progressively upregulated within about 70 µm from the outer rim of iPSC colonies. Single-cell RNA-sequencing demonstrated that OCT4high subsets have pronounced up-regulation of the TGF-β pathway, particularly of NODAL and its inhibitor LEFTY, at the rim of the colonies. Furthermore, calcium-dependent cell-cell interaction seemed to be relevant for the self-organization. After 5 to 7 days, the iPSC colonies detached spontaneously from micro-contact printed substrates to form 3D aggregates. This new method allowed generation of embryoid bodies (EBs) of controlled size, without any enzymatic or mechanical treatment. Within the early 3D aggregates, the radial organization and differential gene expression continued in analogy to the changes observed during self-organization of flat iPSC colonies. Our results provide further insight into the gradual self-organization within iPSC colonies and at their transition into EBs.
2022-08-26 | GSE184603 | GEO
Project description:Colonies of induced pluripotent stem cells (iPSCs) reveal aspects of self-organization even under culture conditions that maintain pluripotent state. To investigate the dynamics of this process under spatial confinement we used either PDMS pillars or micro-contact printing of vitronectin. OCT4, E-cadherin, and NANOG were progressively upregulated within about 70 µm from the outer rim of iPSC colonies. Single-cell RNA-sequencing demonstrated that OCT4high subsets have pronounced up-regulation of the TGF-β pathway, particularly of NODAL and its inhibitor LEFTY, at the rim of the colonies. Furthermore, calcium-dependent cell-cell interaction seemed to be relevant for the self-organization. After 5 to 7 days, the iPSC colonies detached spontaneously from micro-contact printed substrates to form 3D aggregates. This new method allowed generation of embryoid bodies (EBs) of controlled size, without any enzymatic or mechanical treatment. Within the early 3D aggregates, the radial organization and differential gene expression continued in analogy to the changes observed during self-organization of flat iPSC colonies. Our results provide further insight into the gradual self-organization within iPSC colonies and at their transition into EBs.
2022-08-26 | GSE160665 | GEO
Project description:The spatial self-organization within pluripotent stem cell colonies is continued in detaching aggregates
| PRJNA765340 | ENA
Project description:The spatial self-organization within pluripotent stem cell colonies is continued in detaching aggregates (scRNA-Seq)
| PRJNA765347 | ENA
Project description:The spatial self-organization within pluripotent stem cell colonies is continued in detaching aggregates (bulk RNA-Seq)
| PRJNA673890 | ENA
Project description:Human pluripotent stem cells (hPSCs) have the intrinsic ability to self-organize into complex multicellular organoids that recapitulate many aspects of tissue development. However, robustly directing morphogenesis of hPSC-derived organoids requires novel approaches to accurately control self-directed pattern formation. Here, we combined genetic engineering with computational modeling, machine learning, and mathematical pattern optimization to create a data-driven approach to control hPSC self-organization by knock down of genes previously shown to affect stem cell colony organization, CDH1 and ROCK1. Computational replication of the in vitro system in silico using an extended cellular Potts model enabled machine learning-driven optimization of parameters that yielded emergence of desired patterns. Furthermore, in vitro the predicted experimental parameters quantitatively recapitulated the in silico patterns. These results demonstrate that morphogenic dynamics can be accurately predicted through model-driven exploration of hPSC behaviors via machine learning, thereby enabling spatial control of multicellular patterning to engineer human organoids and tissues. A record of this paper's Transparent Peer Review process is included in the Supplemental Information.
| S-EPMC7089762 | biostudies-literature
Project description:Stem cell fate and specification is largely controlled by extrinsic cues that comprise the 3D microenvironment. Biomaterials can serve to control the spatial and temporal presentation of morphogenic molecules in order to direct stem cell fate decisions. Here we describe a microparticle (MP)-based approach to deliver growth factors within multicellular aggregates to direct pluripotent stem cell differentiation. Compared to conventional soluble delivery methods, gelatin MPs laden with BMP4 or noggin induced efficient gene expression of mesoderm and ectoderm lineages, respectively, despite using nearly 12-fold less total growth factor. BMP4-laden MPs increased the percentage of cells expressing GFP under the control of the Brachyury-T promoter as visualized by whole-mount confocal imaging and quantified by flow cytometry. Furthermore, the ability to localize MPs laden with different morphogens within a particular hemisphere of stem cell aggregates allowed for spatial control of differentiation within 3D cultures. Overall, localized delivery of growth factors within multicellular aggregates from microparticle delivery vehicles is an important step towards scalable differentiation technologies and the study of morphogen gradients in pluripotent stem cell differentiation.
| S-EPMC3800695 | biostudies-literature
Project description:The relevance of topographic cues for commitment of induced pluripotent stem cells (iPSCs) is largely unknown. In this study, we demonstrate that groove-ridge structures with a periodicity in the submicrometer range induce elongation of iPSC colonies, guide the orientation of apical actin fibers, and direct the polarity of cell division. Elongation of iPSC colonies impacts also on their intrinsic molecular patterning, which seems to be orchestrated from the rim of the colonies. BMP4-induced differentiation is enhanced in elongated colonies, and the submicron grooves impact on the spatial modulation of YAP activity upon induction with this morphogen. Interestingly, TAZ, a YAP paralog, shows distinct cytoskeletal localization in iPSCs. These findings demonstrate that topography can guide orientation and organization of iPSC colonies, which may affect the interaction between mechanosensors and mechanotransducers in iPSCs.
| S-EPMC5550028 | biostudies-literature
Project description:The developing embryo is a remarkable example of self-organization, where functional units are created in a complex spatiotemporal choreography. Recently, human embryonic stem cells (ESCs) have been used to recapitulate in vitro the self-organization programs that are executed in the embryo in vivo. This represents an unique opportunity to address self-organization in humans that is otherwise not addressable with current technologies. In this chapter, we review the recent literature on self-organization of human ESCs, with a particular focus on two examples: formation of embryonic germ layers and neural rosettes. Intriguingly, both activation and elimination of TGFβ signaling can initiate self-organization, albeit with different molecular underpinnings. We discuss the mechanisms underlying the formation of these structures in vitro and explore future challenges in the field.
| S-EPMC5502691 | biostudies-literature
Project description:Human pluripotent stem cells (hPSCs) grow as colonies with epithelial-like features including cell polarity and position-dependent features that contribute to symmetry breaking during development. Our study provides evidence that hPSC colonies exhibit position-dependent differences in apical structures and functions. With this apical difference, edge cells were preferentially labeled with amphipathic dyes, which enabled separation of edge and center cells by fluorescence-activated cell sorting. Transcriptome comparison between center and edge cells showed differential expression of genes related to apicobasal polarization, cell migration, and endocytosis. Accordingly, different kinematics and mechanical dynamics were found between center and edge cells, and perturbed actin dynamics disrupted the position-dependent apical polarity. In addition, our dye-labeling approach could be utilized to sort out a certain cell population in differentiated micropatterned colonies. In summary, hPSC colonies have position-dependent differences in apical structures and properties, and actin dynamics appear to play an important role in the establishment of this position-dependent cell polarity.
| S-EPMC8758941 | biostudies-literature