scholarly journals Control of plant cell fate transitions by transcriptional and hormonal signals

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Christophe Gaillochet ◽  
Thomas Stiehl ◽  
Christian Wenzl ◽  
Juan-José Ripoll ◽  
Lindsay J Bailey-Steinitz ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Temporal Dynamics ◽  
Developmental Trajectories ◽  
Stem Cell Differentiation ◽  
Integrated Approach ◽  
Shoot Meristem ◽  
Environmental Signals ◽  
Auxin Signalling

Plant meristems carry pools of continuously active stem cells, whose activity is controlled by developmental and environmental signals. After stem cell division, daughter cells that exit the stem cell domain acquire transit amplifying cell identity before they are incorporated into organs and differentiate. In this study, we used an integrated approach to elucidate the role of HECATE (HEC) genes in regulating developmental trajectories of shoot stem cells in Arabidopsis thaliana. Our work reveals that HEC function stabilizes cell fate in distinct zones of the shoot meristem thereby controlling the spatio-temporal dynamics of stem cell differentiation. Importantly, this activity is concomitant with the local modulation of cellular responses to cytokinin and auxin, two key phytohormones regulating cell behaviour. Mechanistically, we show that HEC factors transcriptionally control and physically interact with MONOPTEROS (MP), a key regulator of auxin signalling, and modulate the autocatalytic stabilization of auxin signalling output.

MT1-MMP Regulates Hematopoiesis Through HIF-Mediated Chemo-/Cytokine Release From the Bone Marrow Niche,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3409-3409
Author(s):  
Chiemi Nishida ◽  
Kaori Kusubata ◽  
Yoshihiko Tashiro ◽  
Ismael Gritli ◽  
Aki Sato ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Cell Fate ◽  
Conflicts Of Interest ◽  
Stem Cell Differentiation ◽  
Cell Phenotype ◽  
Bone Marrow Niche ◽  
Matrix Remodeling ◽  
Hematopoietic Stem

Abstract Abstract 3409 Stem cells reside in a physical niche, a particular microenvironment. The organization of cellular niches has been shown to play a key role in regulating normal stem cell differentiation, stem cell maintenance and regeneration. Various stem cell niches have been shown to be hypoxic, thereby maintaining the stem cell phenotype, e.g. for hematopoietic stem cells (HSCs) or cancer stem cells. The bone marrow (BM) niche is a rich reservoir for tissue-specific pluripotent HSCs. Proteases, such as matrix metalloproteinases (MMPs) can modulate stem cell fate due to their proteolytic or non-proteolytic functions (abilities). We have investigated the role of membrane-type1 matrix metalloproteinase (MT1-MMP), known for its role in pericellular matrix remodeling and cell migration, in hematopoiesis. MT1-MMP is highly expressed in HSCs and stromal cells. In MT1-MMP−/− mice, release of kit ligand (KitL), stromal cell derived factor-1 (SDF-1/CXCL12), erythropoietin (Epo) and interleukin-7 were impaired resulting in erythroid, myeloid and T and B lymphoid differentiation. Addition of exogenous rec. KitL and rec. SDF-1 restored hematopoiesis in vivo and in vitro. Further mechanistic studies revealed that MT1-MMP in a non-proteolytic manner activates the HIF-1 pathway, thereby inducing the transcription of the HIF-responsive genes KitL, SDF-1 and Epo. These results suggested MT1-MMP as a critical regulator of postnatal hematopoiesis, which as a modulator of the HIF pathway alters critical hematopoietic niche factors necessary for terminal differentiation and or migration. Thus, our results indicate that MT1-MMP as a key molecular link between hypoxia and the regulation of vital HSC niche factors. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Advances in Extracellular Matrix-Mimetic Hydrogels to Guide Stem Cell Fate

2021 ◽  
pp. 1-18
Author(s):  
Ryan S. Stowers
Keyword(s):  
Stem Cells ◽  
Extracellular Matrix ◽  
Stem Cell ◽  
Cell Fate ◽  
Cell Biology ◽  
Stem Cell Differentiation ◽  
Stem Cell Biology ◽  
Stem Cell Fate ◽  
Material Systems

In the fields of regenerative medicine and tissue engineering, stem cells offer vast potential for treating or replacing diseased and damaged tissue. Much progress has been made in understanding stem cell biology, yielding protocols for directing stem cell differentiation toward the cell type of interest for a specific application. One particularly interesting and powerful signaling cue is the extracellular matrix (ECM) surrounding stem cells, a network of biopolymers that, along with cells, makes up what we define as a tissue. The composition, structure, biochemical features, and mechanical properties of the ECM are varied in different tissues and developmental stages, and serve to instruct stem cells toward a specific lineage. By understanding and recapitulating some of these ECM signaling cues through engineered ECM-mimicking hydrogels, stem cell fate can be directed in vitro. In this review, we will summarize recent advances in material systems to guide stem cell fate, highlighting innovative methods to capture ECM functionalities and how these material systems can be used to provide basic insight into stem cell biology or make progress toward therapeutic objectives.

scholarly journals The nuclear import of the transcription factor MyoD is reduced in mesenchymal stem cells grown in a 3D micro-engineered niche

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Emanuela Jacchetti ◽  
Ramin Nasehi ◽  
Lucia Boeri ◽  
Valentina Parodi ◽  
Alessandro Negro ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Stem Cell ◽  
Nuclear Envelope ◽  
Cell Fate ◽  
Nuclear Import ◽  
Numerical Models ◽  
Stem Cell Differentiation ◽  
Nuclear Pore

AbstractSmart biomaterials are increasingly being used to control stem cell fate in vitro by the recapitulation of the native niche microenvironment. By integrating experimental measurements with numerical models, we show that in mesenchymal stem cells grown inside a 3D synthetic niche both nuclear transport of a myogenic factor and the passive nuclear diffusion of a smaller inert protein are reduced. Our results also suggest that cell morphology modulates nuclear proteins import through a partition of the nuclear envelope surface, which is a thin but extremely permeable annular portion in cells cultured on 2D substrates. Therefore, our results support the hypothesis that in stem cell differentiation, the nuclear import of gene-regulating transcription factors is controlled by a strain-dependent nuclear envelope permeability, probably related to the reorganization of stretch-activated nuclear pore complexes.

scholarly journals PASsing on Signals: PAS Kinase (PASK)-mTOR Signaling Conveys Nutrient Sufficiency Signals to Epigenetic (COMPASS) Complexes to Activate Stem Cell Differentiation Program (P15-009-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Chintan Kikani ◽  
Michael Xiao ◽  
Xiaoying Wu ◽  
Jared Rutter
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Differentiation ◽  
Cell Fate ◽  
Early Stage ◽  
Stem Cell Differentiation ◽  
Mtor Signaling ◽  
Kinase Assay ◽  
Cell Functions ◽  
Nutrient Signaling

Abstract Objectives To determine how nutrient signaling impacts stem cell functions Methods PASK phosphorylation: We measured in situ phosphorylation of PASK by metabolic 32P labeling of stem cells expressing WT or mutant versions of PASK. PASK Activation: PASK activation was measured using in vitro kinase assay using radio-labeled ATP. Myogenesis: Myogenesis was measured by immunohistological, and immunofluorescent analysis of differentiating muscle stem cells. Antibodies used were: Myogenin (F5D-Developmental Hybridoma), MF20 (Myosin heavy chain), Pax7 and MyoD. Results Stem cell fate in the tissue niche is intimately connected with intracellular metabolic state and the extracellular hormonal stimulations. We have identified PAS domain containing Kinase (PASK) as a stem cell enriched protein kinase that is required for establishment of the differentiation program in many stem cell paradigms. For this function, PASK phosphorylates Wdr5, a member of the COMPASS family of histone methyltransferases, to activate the epigenetic processes required for the stem cell differentiation (eLife, 2016). Here we show that a master nutrient sensor, mTOR complex 1 (mTORC1) activates PASK via multi-site phosphorylation during stem cell differentiation. This phosphorylation of PASK by mTORC1 is required for epigenetic activation of the Myogenin transcription, exit from the self-renewal and induction of the myogenesis program. Our data suggest that mTORC1-PASK signaling generates MyoG + committed myoblasts (epigenetically - an early stage of myogenesis), whereas mTORC1-S6K1 signaling is required for myoblast fusion (translationally - later stage of myogenesis). Conclusions Our discoveries show that nutrient signaling can partition stem cell fates during different stages of the myogenesis program downstream of mTOR signaling via activation of two distinct protein kinases. Funding Sources NIH R01 (Chintan Kikani), HHMI (Jared Rutter) Supporting Tables, Images and/or Graphs

scholarly journals mTORC1 activates PASK-Wdr5 signaling to epigenetically connect the nutrient status with myogenesis

2017 ◽  
Author(s):  
Chintan K. Kikani ◽  
Xiaoying Wu ◽  
Sarah Fogarty ◽  
Seong Anthony Woo Kang ◽  
Noah Dephoure ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Nutrient Status ◽  
Stem Cell Differentiation ◽  
Self Renewal ◽  
Muscle Stem Cell ◽  
Downstream Target ◽  
Cell Functions ◽  
Dietary Nutrients

SummaryIn the tissue microenvironment, stem cell functions are modulated by extrinsic signaling cues such as peptide hormones and dietary nutrients. These signaling cues maintain the balance between self-renewal and differentiation of its resident stem cells. The mechanistic Target of Rapamycin Complex 1 (mTORC1) is implicated to play an important role in regulating this balance, although its downstream effectors in stem cells have been elusive. We have recently shown that the PASK protein kinase phosphorylates Wdr5 to stimulate muscle stem cell differentiation by epigenetically activating the Myogenin promoter. Here, we show that the PASK-Wdr5 signaling pathway is a nutrient-sensitive downstream target of mTORC1 in muscle stem cells. We show that phosphorylation of PASK, and in turn of Wdr5, by mTORC1 is required for the activation of Myogenin transcription, exit from the self-renewal and induction of the myogenesis program. Thus, mTOR connects the diverse extrinsic signaling cues to a central epigenetic process to regulate the muscle stem cell fate between self-renewal and differentiation.

scholarly journals Using single-cell entropy to describe the dynamics of reprogramming and differentiation of induced pluripotent stem cells

2020 ◽  
Vol 34 (30) ◽  
pp. 2050288
Author(s):  
Y. Ye ◽  
Z. Yang ◽  
M. Zhu ◽  
J. Lei
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Differentiation ◽  
Single Cell ◽  
Cell Fate ◽  
Pluripotent Stem Cells ◽  
Stem Cell Differentiation ◽  
Cell Level ◽  
Macroscopic Variable ◽  
Induced Pluripotent

Induced pluripotent stem cells (iPSCs) provide a great model to study the process of stem cell reprogramming and differentiation. Single-cell RNA sequencing (scRNA-seq) enables us to investigate the reprogramming process at single-cell level. Here, we introduce single-cell entropy (scEntropy) as a macroscopic variable to quantify the cellular transcriptome from scRNA-seq data during reprogramming and differentiation of iPSCs. scEntropy measures the relative order parameter of genomic transcriptions at single cell level during the process of cell fate changes, which show increase tendency during differentiation, and decrease upon reprogramming. Hence, scEntropy provides an intrinsic measurement of the cell state, and can be served as a pseudo-time of the stem cell differentiation process. Moreover, based on the evolutionary dynamics of scEntropy, we construct a phenomenological Fokker-Planck equation model and the corresponding stochastic differential equation for the process of cell state transitions during pluripotent stem cell differentiation. These equations provide further insights to infer the processes of cell fates changes and stem cell differentiation. This study is the first to introduce the novel concept of scEntropy to quantify the biological process of iPSC, and suggests that the scEntropy can provide a suitable macroscopic variable for single cells to describe cell fate transition during differentiation and reprogramming of stem cells.

scholarly journals Decoding the mechanisms underlying cell-fate decision-making during stem cell differentiation by random circuit perturbation

2020 ◽  
Vol 17 (169) ◽  
pp. 20200500
Author(s):  
Bin Huang ◽  
Mingyang Lu ◽  
Madeline Galbraith ◽  
Herbert Levine ◽  
Jose N. Onuchic ◽  
...  
Keyword(s):  
Decision Making ◽  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Expression Patterns ◽  
Stem Cell Differentiation ◽  
Computational Method ◽  
Embryonic Cells ◽  
Fate Decision ◽  
Stem Cell Populations

Stem cells can precisely and robustly undergo cellular differentiation and lineage commitment, referred to as stemness. However, how the gene network underlying stemness regulation reliably specifies cell fates is not well understood. To address this question, we applied a recently developed computational method, ra ndom ci rcuit pe rturbation (RACIPE), to a nine-component gene regulatory network (GRN) governing stemness, from which we identified robust gene states. Among them, four out of the five most probable gene states exhibit gene expression patterns observed in single mouse embryonic cells at 32-cell and 64-cell stages. These gene states can be robustly predicted by the stemness GRN but not by randomized versions of the stemness GRN. Strikingly, we found a hierarchical structure of the GRN with the Oct4/Cdx2 motif functioning as the first decision-making module followed by Gata6/Nanog. We propose that stem cell populations, instead of being viewed as all having a specific cellular state, can be regarded as a heterogeneous mixture including cells in various states. Upon perturbations by external signals, stem cells lose the capacity to access certain cellular states, thereby becoming differentiated. The new gene states and key parameters regulating transitions among gene states proposed by RACIPE can be used to guide experimental strategies to better understand differentiation and design reprogramming. The findings demonstrate that the functions of the stemness GRN is mainly determined by its well-evolved network topology rather than by detailed kinetic parameters.

scholarly journals Using single-cell entropy to describe the dynamics of reprogramming and differentiation of induced pluripotent stem cells

2020 ◽  
Author(s):  
Yusong Ye ◽  
Zhuoqin Yang ◽  
Meixia Zhu ◽  
Jinzhi Lei
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Differentiation ◽  
Single Cell ◽  
Cell Fate ◽  
Pluripotent Stem Cells ◽  
Stem Cell Differentiation ◽  
Cell Level ◽  
Macroscopic Variable ◽  
Induced Pluripotent

AbstractInduced pluripotent stem cells (iPSCs) provide a great model to study the process of stem cell reprogramming and differentiation. Single-cell RNA sequencing (scRNA-seq) enables us to investigate the reprogramming process at single-cell level. Here, we introduce single-cell entropy (scEntropy) as a macroscopic variable to quantify the cellular transcriptome from scRNA-seq data during reprogramming and differentiation of iPSCs. scEntropy measures the relative order parameter of genomic transcriptions at single cell level during the process of cell fate changes, which show increase tendency during differentiation, and decrease upon reprogramming. Hence, scEntropy provides an intrinsic measurement of the cell state, and can be served as a pseudo-time of the stem cell differentiation process. Moreover, based on the evolutionary dynamics of scEntropy, we construct a phenomenological Fokker-Planck equation model and the corresponding stochastic differential equation for the process of cell state transitions during pluripotent stem cell differentiation. These equations provide further insights to infer the processes of cell fates changes and stem cell differentiation. This study is the first to introduce the novel concept of scEntropy to quantify the biological process of iPSC, and suggests that the scEntropy can provide a suitable macroscopic variable for single cells to describe cell fate transition during differentiation and reprogramming of stem cells.

scholarly journals STEM-15. RADIATION-INDUCED MODULATION OF NEURODEVELOPMENTAL PATHWAYS IN CLASSICAL GLIOMA STEM CELLS

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi236-vi237
Author(s):  
Costanza Lo Cascio ◽  
Ernesto Luna Melendez ◽  
James McNamara ◽  
Robert Schultz ◽  
An-Chi Tien ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Ionizing Radiation ◽  
Cell Fate ◽  
Neural Stem Cell ◽  
Molecular Mechanisms ◽  
Temporal Dynamics ◽  
Cell Phenotype ◽  
Glioma Stem Cells ◽  
Radiation Induced

Abstract The current standard-of-care treatment for GBM is ineffective and fails to significantly prolong survival. Following exposure to aggressive multimodal treatment, GBMs have been shown to frequently shift their biological features upon recurrence, acquiring a more resistant phenotype. However, the temporal dynamics and molecular mechanisms that facilitate GBM recurrence are poorly understood. The objective of our study was to assess the acute response to ionizing radiation in glioma stem cells (GSCs) from the Classical subtype of GBM in vitro and in vivo. We find that Classical GSCs rapidly undergo dramatic molecular and cellular changes in response to single and fractionated doses of ionizing radiation, resulting in a heterogeneous cell population. Ionizing radiation causes a transient decrease in the expression of key stemness genes (e.g., SOX2) followed by drastic morphological changes and a concomitant significant increase in the levels of key cell fate markers expressed in adult quiescent neural stem cells. Radiation-induced alteration of SOX2 levels in Classical GSCs is dependent on intact p53 signaling. GSCs previously exposed to radiation are more radio-resistant upon re-treatment compared to their naïve, untreated counterparts – suggesting that the aforementioned phenotypic shift to a quiescent neural stem cell phenotype promotes treatment resistance. Our results suggest that cell-intrinsic factors dictate how GSCs respond to radiation, and that Classical GSCs are neurodevelopmentally predisposed to shift towards an astrocytic/neural stem cell identity in response to cellular stress.

AFM Assessment of the Mechanical Properties of Stem Cells During Differentiation

MRS Advances ◽  
2019 ◽  
Vol 5 (12-13) ◽  
pp. 601-607
Author(s):  
Jie Zou ◽  
Weiwei Wang ◽  
Xianlei Sun ◽  
Wingtai Tung ◽  
Nan Ma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stem Cells ◽  
Flow Cytometry ◽  
Stem Cell ◽  
Cell Differentiation ◽  
Cell Fate ◽  
Stem Cell Differentiation ◽  
Cell Nuclei ◽  
Gene And Protein Expression ◽  
Marrow Mesenchymal Stem Cells

ABSTRACTThe dynamic mechanical force transmitted through microenvironments during tissue formation and regeneration continuously impacts the mechanics of cells and thereby regulates gene and protein expression. The mechanical properties are altered during the process of stem cells differentiating into different lineages. At different stages of differentiation, stem cells display different mechanical properties in response to surrounding microenvironments, which depend on the subcellular structures, especially the cytoskeleton and nucleus. The mechanical properties of the cell nucleus affect protein folding and transport as well as the condensation of chromatin, through which the cell fate is regulated. These findings raise the question as to how cell mechanics change during differentiation. In this study, the mechanical properties of human bone marrow mesenchymal stem cells (hBMSCs) were determined during adipogenic and osteogenic differentiation by atomic force microscopy (AFM). The cytoskeletal structure and the modification of histone were investigated using laser confocal microscope and flow cytometry. The mechanical properties of cell nuclei at different stages of cell differentiation were compared. The stiffness of nuclei increased with time as osteogenesis was induced in hBMSCs. The H3K27me3 level increased during osteogenesis and adipogenesis according to flow cytometry analysis. Our results show conclusively that AFM is a facile and effective method to monitor stem cell differentiation. The measurement of cell mechanical properties by AFM improves our understanding on the connection between mechanics and stem cell fate.

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