scholarly journals StemBond hydrogels control the mechanical microenvironment for pluripotent stem cells

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Céline Labouesse ◽  
Bao Xiu Tan ◽  
Chibeza C. Agley ◽  
Moritz Hofer ◽  
Alexander K. Winkel ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Pluripotent Stem Cells ◽  
Cell Function ◽  
Cell Attachment ◽  
Substrate Stiffness ◽  
Cell Fate Specification ◽  
Confounding Variable ◽  
Mechanical Microenvironment

AbstractStudies of mechanical signalling are typically performed by comparing cells cultured on soft and stiff hydrogel-based substrates. However, it is challenging to independently and robustly control both substrate stiffness and extracellular matrix tethering to substrates, making matrix tethering a potentially confounding variable in mechanical signalling investigations. Moreover, unstable matrix tethering can lead to poor cell attachment and weak engagement of cell adhesions. To address this, we developed StemBond hydrogels, a hydrogel in which matrix tethering is robust and can be varied independently of stiffness. We validate StemBond hydrogels by showing that they provide an optimal system for culturing mouse and human pluripotent stem cells. We further show how soft StemBond hydrogels modulate stem cell function, partly through stiffness-sensitive ERK signalling. Our findings underline how substrate mechanics impact mechanosensitive signalling pathways regulating self-renewal and differentiation, indicating that optimising the complete mechanical microenvironment will offer greater control over stem cell fate specification.

scholarly journals StemBond hydrogels optimise the mechanical microenvironment for embryonic stem cells

2019 ◽  
Author(s):  
Céline Labouesse ◽  
Chibeza C. Agley ◽  
Bao Xiu Tan ◽  
Moritz Hofer ◽  
Alex Winkel ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cell Attachment ◽  
Es Cells ◽  
Embryonic Stem ◽  
Cellular Reprogramming ◽  
Substrate Stiffness ◽  
Cell Fate Specification ◽  
Es Cell ◽  
Self Renewal ◽  
Mechanical Microenvironment

ABSTRACTStudies of mechanical signalling are typically performed by comparing cells cultured on soft and stiff hydrogel-based substrates. However, it is challenging to independently and robustly control both substrate stiffness and tethering of extracellular matrix (ECM) to substrates, making ECM tethering a potentially confounding variable in mechanical signalling investigations. Moreover, poor ECM tethering can lead to weak cell attachment. To address this, we developed StemBond hydrogels, a hydrogel formulation in which ECM tethering is stable and can be varied independently of stiffness. We show that soft StemBond hydrogels provide an optimal format for culturing embryonic stem (ES) cells. We find that soft StemBond substrates improve the homogeneity of ES cell populations, boost their self-renewal, and increase the efficiency of cellular reprogramming. Our findings underline how soft microenvironments impact mechanosensitive signalling pathways regulating self-renewal and differentiation, indicating that optimising the complete mechanical microenvironment will offer greater control over stem cell fate specification.

scholarly journals Controlling Self-Renewal and Differentiation of Stem Cells via Mechanical Cues

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Michele M. Nava ◽  
Manuela T. Raimondi ◽  
Riccardo Pietrabissa
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Cell Response ◽  
Recent Literature ◽  
Focal Adhesions ◽  
Substrate Stiffness ◽  
Self Renewal ◽  
Mechanical Factors

The control of stem cell responsein vitro, including self-renewal and lineage commitment, has been proved to be directed by mechanical cues, even in the absence of biochemical stimuli. Through integrin-mediated focal adhesions, cells are able to anchor onto the underlying substrate, sense the surrounding microenvironment, and react to its properties. Substrate-cell and cell-cell interactions activate specific mechanotransduction pathways that regulate stem cell fate. Mechanical factors, including substrate stiffness, surface nanotopography, microgeometry, and extracellular forces can all have significant influence on regulating stem cell activities. In this paper, we review all the most recent literature on the effect of purely mechanical cues on stem cell response, and we introduce the concept of “force isotropy” relevant to cytoskeletal forces and relevant to extracellular loads acting on cells, to provide an interpretation of how the effects of insoluble biophysical signals can be used to direct stem cells fatein vitro.

scholarly journals Drosophila neuroblasts as a new model for the study of stem cell self-renewal and tumour formation

2014 ◽  
Vol 34 (4) ◽  
Author(s):  
Song Li ◽  
Hongyan Wang ◽  
Casper Groth
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Daughter Cell ◽  
Asymmetric Cell Division ◽  
Cell Fate Specification ◽  
Larval Brain ◽  
Self Renewal ◽  
Intrinsic Factors ◽  
Tumour Formation

Drosophila larval brain stem cells (neuroblasts) have emerged as an important model for the study of stem cell asymmetric division and the mechanisms underlying the transformation of neural stem cells into tumour-forming cancer stem cells. Each Drosophila neuroblast divides asymmetrically to produce a larger daughter cell that retains neuroblast identity, and a smaller daughter cell that is committed to undergo differentiation. Neuroblast self-renewal and differentiation are tightly controlled by a set of intrinsic factors that regulate ACD (asymmetric cell division). Any disruption of these two processes may deleteriously affect the delicate balance between neuroblast self-renewal and progenitor cell fate specification and differentiation, causing neuroblast overgrowth and ultimately lead to tumour formation in the fly. In this review, we discuss the mechanisms underlying Drosophila neural stem cell self-renewal and differentiation. Furthermore, we highlight emerging evidence in support of the notion that defects in ACD in mammalian systems, which may play significant roles in the series of pathogenic events leading to the development of brain cancers.

scholarly journals Mitochondrial state determines functionally divergent stem cell population in planaria

2020 ◽  
Author(s):  
Mohamed Mohamed Haroon ◽  
Vairavan Lakshmanan ◽  
Souradeep R Sarkar ◽  
Kai Lei ◽  
Praveen Kumar Vemula ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Pluripotent Stem Cells ◽  
Cell Function ◽  
Cultured Cells ◽  
Stem Cell Population ◽  
Mitochondrial Content ◽  
Mitochondrial Mass ◽  
State Changes ◽  
Transplantation Experiments

Mitochondrial state changes were shown to be critical for stem cell function. However, variation in the mitochondrial content in stem cells and the implication, if any, on differentiation is poorly understood. Here, using cellular and molecular studies, we show that the planarian pluripotent stem cells (PSCs) have low mitochondrial mass compared to its progenitors. Further, the mitochondrial mass correlated with OxPhos and inhibiting the transition to OxPhos dependent metabolism in cultured cells resulted in higher PIWI-1High neoblasts. Transplantation experiments provided functional validation that neoblasts with low mitochondrial mass are the true PSCs. In summary, we show that low mitochondrial mass is a hallmark of PSCs in planaria and provide a mechanism to isolate live, functionally active, PSCs from different cell cycle stages (G0/G1 and S, G2/M). Our study demonstrates that the change in mitochondrial metabolism, a feature of PSCs is conserved in planaria and highlights its role in organismal regeneration.

scholarly journals Plant stem-cell organization and differentiation at single-cell resolution

2020 ◽  
Vol 117 (52) ◽  
pp. 33689-33699
Author(s):  
James W. Satterlee ◽  
Josh Strable ◽  
Michael J. Scanlon
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Differentiation ◽  
Single Cell ◽  
Cell Fate ◽  
Cell Function ◽  
Ectopic Expression ◽  
Cellular Level ◽  
Organizing Center ◽  
Cell Niche

Plants maintain populations of pluripotent stem cells in shoot apical meristems (SAMs), which continuously produce new aboveground organs. We used single-cell RNA sequencing (scRNA-seq) to achieve an unbiased characterization of the transcriptional landscape of the maize shoot stem-cell niche and its differentiating cellular descendants. Stem cells housed in the SAM tip are engaged in genome integrity maintenance and exhibit a low rate of cell division, consistent with their contributions to germline and somatic cell fates. Surprisingly, we find no evidence for a canonical stem-cell organizing center subtending these cells. In addition, trajectory inference was used to trace the gene expression changes that accompany cell differentiation, revealing that ectopic expression of KNOTTED1 (KN1) accelerates cell differentiation and promotes development of the sheathing maize leaf base. These single-cell transcriptomic analyses of the shoot apex yield insight into the processes of stem-cell function and cell-fate acquisition in the maize seedling and provide a valuable scaffold on which to better dissect the genetic control of plant shoot morphogenesis at the cellular level.

scholarly journals Heterochromatin protein 1 promotes self-renewal and triggers regenerative proliferation in adult stem cells

2013 ◽  
Vol 201 (3) ◽  
pp. 409-425 ◽  
Author(s):  
An Zeng ◽  
Yong-Qin Li ◽  
Chen Wang ◽  
Xiao-Shuai Han ◽  
Ge Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Adult Stem Cells ◽  
Cell Function ◽  
Heterochromatin Protein 1 ◽  
Self Renewal ◽  
Blastema Formation ◽  
Cell Fate Decisions ◽  
Chromatin Regulators

Adult stem cells (ASCs) capable of self-renewal and differentiation confer the potential of tissues to regenerate damaged parts. Epigenetic regulation is essential for driving cell fate decisions by rapidly and reversibly modulating gene expression programs. However, it remains unclear how epigenetic factors elicit ASC-driven regeneration. In this paper, we report that an RNA interference screen against 205 chromatin regulators identified 12 proteins essential for ASC function and regeneration in planarians. Surprisingly, the HP1-like protein SMED–HP1-1 (HP1-1) specifically marked self-renewing, pluripotent ASCs, and HP1-1 depletion abrogated self-renewal and promoted differentiation. Upon injury, HP1-1 expression increased and elicited increased ASC expression of Mcm5 through functional association with the FACT (facilitates chromatin transcription) complex, which consequently triggered proliferation of ASCs and initiated blastema formation. Our observations uncover an epigenetic network underlying ASC regulation in planarians and reveal that an HP1 protein is a key chromatin factor controlling stem cell function. These results provide important insights into how epigenetic mechanisms orchestrate stem cell responses during tissue regeneration.

scholarly journals Definitive Endoderm Formation from Plucked Human Hair-Derived Induced Pluripotent Stem Cells and SK Channel Regulation

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Anett Illing ◽  
Marianne Stockmann ◽  
Narasimha Swamy Telugu ◽  
Leonhard Linta ◽  
Ronan Russell ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Induced Pluripotent Stem Cells ◽  
Cell Fate ◽  
Pluripotent Stem Cells ◽  
Human Hair ◽  
Definitive Endoderm ◽  
Sk Channel ◽  
Induced Pluripotent

Pluripotent stem cells present an extraordinary powerful tool to investigate embryonic development in humans. Essentially, they provide a unique platform for dissecting the distinct mechanisms underlying pluripotency and subsequent lineage commitment. Modest information currently exists about the expression and the role of ion channels during human embryogenesis, organ development, and cell fate determination. Of note, small and intermediate conductance, calcium-activated potassium channels have been reported to modify stem cell behaviour and differentiation. These channels are broadly expressed throughout human tissues and are involved in various cellular processes, such as the after-hyperpolarization in excitable cells, and also in differentiation processes. To this end, human induced pluripotent stem cells (hiPSCs) generated from plucked human hair keratinocytes have been exploitedin vitroto recapitulate endoderm formation and, concomitantly, used to map the expression of the SK channel (SKCa) subtypes over time. Thus, we report the successful generation of definitive endoderm from hiPSCs of ectodermal origin using a highly reproducible and robust differentiation system. Furthermore, we provide the first evidence that SKCas subtypes are dynamically regulated in the transition from a pluripotent stem cell to a more lineage restricted, endodermal progeny.

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.

Stem Cell Based Preclinical Drug Development and Toxicity Prediction

2020 ◽  
Vol 26 ◽  
Author(s):  
Dhruv Kumar ◽  
Prakash Baligar ◽  
Rajpal Srivastav ◽  
Priyanka Narad ◽  
Sibi Raj ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Drug Development ◽  
Pluripotent Stem Cells ◽  
Cell Function ◽  
Embryonic Stem ◽  
Specific Cell ◽  
Toxicity Prediction ◽  
In Vivo Models ◽  
The Impact

: Stem cell based toxicity prediction plays very important role in the development of drug. Unexpected adverse effects of the drugs during clinical trials are a major reason for termination or withdrawal of drugs. Methods for predicting toxicity employ in vitro as well as in vivo models, however, the major drawback seen in the data derived from these animal models is lack of extrapolation, owing to interspecies variations. Due to these limitations, researchers have been striving to develop more robust drug screening platforms based on stem cells. The application of stem cells based toxicity testing has opened up robust methods to study the impact of new chemical entities on not only specific cell types, but also organs. Pluripotent stem cells, as well as cells derived from them, can be evaluated for modulation of cell function in response to drugs. Moreover, the combination of state-of-the -art techniques such as tissue engineering and microfluidics to fabricate organ-on-a-chip, has led to assays which are amenable to high throughput screening to understand the adverse and toxic effects of chemicals and drugs. This review summarizes the important aspects of the establishment of the embryonic stem cell test (EST), use of stem cells, pluripotent, induced pluripotent stem cells and organoids for toxicity prediction and drug development.

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