Project description:Stem cells maintain a dynamic dialogue with their niche, integrating biochemical and biophysical cues to modulate cellular behavior. Yet, the transcriptional networks that regulate cellular biophysical properties remain poorly defined. Here, we leverage human pluripotent stem cells (hPSCs) and two morphogenesis models – gastruloids and pancreatic differentiation – to establish ETV transcription factors as critical regulators of biophysical parameters and lineage commitment. Genetic ablation of ETV1 or ETV1/ETV4/ETV5 in hPSCs enhanced cell-cell and cell-ECM adhesion, leading to aberrant multilineage differentiation including disrupted germ-layer organization, ectoderm loss, and extraembryonic cell overgrowth in gastruloids. Furthermore, ETV1 loss abolished pancreatic progenitor formation. Single-cell RNA sequencing and follow-up assays revealed dysregulated mechanotransduction via the PI3K/AKT signaling. Our findings highlight the importance of transcriptional control over cell biophysical properties and suggest that manipulating these properties may improve in vitro cell and tissue engineering strategies.
Project description:Identify the molecular cues (genes) which shape the biochemical composition and the nanomechanical properties of the cell wall of Saccharomyces cerevisae and the links between these two parameters represent a major issue in the understanding of the biogenesis and the molecular assembly of this essential cellular structure, which may have consequences in diverse biotechnological applications. Firstly, we compared the biochemical and biophysical properties of 4 industrial strains with the laboratory sequenced strain BY4743 and used transcriptome data of these strains to infer biological hypothesis about differences of these properties between strains. The second approach was to employ a multivariate statistical analysis to identify highly correlated variables among biochemical, biophysical and genes expression data.
Project description:Lung cancers are documented to have remarkable intratumoral genetic heterogeneity. However, little is known about the heterogeneity of biophysical properties, such as cell motility, and its relationship to early disease pathogenesis and micrometastatic dissemination. In this study, we identified and selected a subpopulation of highly migratory premalignant pulmonary epithelial cells that were observed to migrate through microscale constrictions at up to 100-fold the rate of unselected cells. This enhanced migratory capacity was found to be Rac1-dependent and heritable, as evidenced by maintenance of the phenotype through multiple cell divisions continuing more than 8-weeks post-selection. The morphology of this lung epithelial subpopulation was characterized by increased cell protrusion intensity. In a murine model of micrometastatic seeding and pulmonary colonization, the motility-selected premalignant cells exhibit both enhanced survival in short term assays and enhanced outgrowth of premalignant lesions in longer term assays, thus overcoming important aspects of “metastatic inefficiency.” Overall, our findings indicate that among premalignant pulmonary epithelial cells, subpopulations with heritable motility-related biophysical properties exist, and these may explain micrometastatic seeding occurring early in the pathogenesis of lung cancer. Understanding, targeting, and preventing these critical biophysical traits and their underlying molecular mechanisms may provide a new approach to prevent metastatic behavior.
Project description:Immune cells identify cancer cells by recognizing characteristic biochemical features indicative of oncogenic transformation. Cancer cells have characteristic mechanical features, as well, but whether these biophysical properties also contribute to destruction by the immune system is not known. In the present study, we found that enhanced expression of myocardin related transcription factors (MRTFs), which promote migration and metastatic invasion, paradoxically compromised lung colonization by melanoma and breast carcinoma cells in an immune-mediated manner. Cancer cells with increased MRTF signaling were also more sensitive to immune checkpoint blockade therapy in mice and humans. The basis for this vulnerability was not biochemical, but biophysical. MRTF expression strengthened the actin cytoskeleton, increasing the rigidity of cancer cells and thereby making them more vulnerable to cytotoxic T lymphocytes and natural killer cells. These results reveal a mechanical dimension of immunosurveillance, which we call mechanosurveillance, that is particularly relevant to the targeting of metastatic disease.
Project description:Neurons derived from human pluripotent stem cells (hPSCs) are a remarkable tool for modeling human neural development and diseases. However, it remains largely unknown whether the hPSC-derived neurons can be functionally coupled with their target tissues in vitro, which is essential for understanding inter-cellular physiology and further translational studies. Here, we demonstrate that hPSC-derived sympathetic neurons can be obtained from hPSCs and that the resulting neurons form physical and functional connections with cardiac muscle cells. By use of multiple hPSC reporter lines, we recapitulated human autonomic neuron development in vitro, and successfully isolated PHOX2B::eGFP+ neurons exhibiting sympathetic marker expression, electrophysiological properties, and norepinephrine secretion. With pharmacological and optogenetic manipulations, the PHOX2B::eGFP+ neurons controlled the beating rates of cardiomyocytes, and their physical interaction led to neuronal maturation. Our study lays a foundation for the specification of human sympathetic neurons and for the hPSC-based neuronal control of end organs in a dish. Using the four genetic reporter systems (OCT4::eGFP, SOX10::eGFP, ASCL1::eGFP, and PHOX2B::eGFP reporter hESC lines), we were able to purify discrete cell populations at four differentiation stages, recapitulating the sympathoadrenal differentiation process in vitro with purified and defined populations in four specific differentiation stages. We performed transcriptome analysis of OCT4::eGFP+ cells (3 biological replicates, representing undifferentiated hESCs), SOX10::eGFP+ cells (3 biological replicates, multi-potent neural crest), ASCL1::eGFP+ cells (3 biological replicates, putative sympathoadrenal progenitors), and PHOX2B::eGFP+ cells (2 biological replicates, putative sympathetic neuronal precursors).
Project description:N-terminal coding sequences (NCS) are key regulatory elements for fine-tuning gene expression during translation initiation, the rate-limiting step of translation. However, due to complex combinatory effects of NCS biophysical factors and endogenous regulation, designing NCS remains challenging. Herein, we implemented multi-view learning strategy for model-driven generation of synthetic NCS for Saccharomyces cerevisiae and Bacillus subtilis, which are model microorganisms widely used in the laboratory and industry.
Project description:This SuperSeries is composed of the following subset Series: GSE38560: CpG islands and GC content dictate nucleosome depletion in a transcription independent manner at mammalian promoters (RNA-seq) GSE38561: CpG islands and GC content dictate nucleosome depletion in a transcription independent manner at mammalian promoters (ChIP-seq) GSE38562: CpG islands and GC content dictate nucleosome depletion in a transcription independent manner at mammalian promoters (genomic SEQ) GSE38563: CpG islands and GC content dictate nucleosome depletion in a transcription independent manner at mammalian promoters (MNase-seq) GSE38564: CpG islands and GC content dictate nucleosome depletion in a transcription independent manner at mammalian promoters (5) Refer to individual Series
Project description:scRNAseq of sequential time points and CDKi-treated samples during endothelial-to-haematopoietic transition in cells derived by hPSC differentiation.