Insight into Hypoxia Stemness Control

Recently, the research on stemness and multilineage differentiation mechanisms has greatly increased its value due to the potential therapeutic impact of stem cell-based approaches. Stem cells modulate their self-renewing and differentiation capacities in response to endogenous and/or extrinsic factors that can control stem cell fate. One key factor controlling stem cell phenotype is oxygen (O2). Several pieces of evidence demonstrated that the complexity of reproducing O2 physiological tensions and gradients in culture is responsible for defective stem cell behavior in vitro and after transplantation. This evidence is still worsened by considering that stem cells are conventionally incubated under non-physiological air O2 tension (21%). Therefore, the study of mechanisms and signaling activated at lower O2 tension, such as those existing under native microenvironments (referred to as hypoxia), represent an effective strategy to define if O2 is essential in preserving naïve stemness potential as well as in modulating their differentiation. Starting from this premise, the goal of the present review is to report the status of the art about the link existing between hypoxia and stemness providing insight into the factors/molecules involved, to design targeted strategies that, recapitulating naïve O2 signals, enable towards the therapeutic use of stem cell for tissue engineering and regenerative medicine.

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Regulation and Directing Stem Cell Fate by Tissue Engineering Functional Microenvironments: Scaffold Physical and Chemical Cues

Stem Cells International ◽

10.1155/2019/2180925 ◽

2019 ◽

Vol 2019 ◽

pp. 1-16 ◽

Cited By ~ 8

Author(s):

Fei Xing ◽

Lang Li ◽

Changchun Zhou ◽

Cheng Long ◽

Lina Wu ◽

...

Keyword(s):

Tissue Engineering ◽

Stem Cells ◽

Stem Cell ◽

Growth Factors ◽

Cell Fate ◽

Chemical Cues ◽

Physical Factors ◽

Stem Cell Fate ◽

Physical And Chemical

It is well known that stem cells reside within tissue engineering functional microenvironments that physically localize them and direct their stem cell fate. Recent efforts in the development of more complex and engineered scaffold technologies, together with new understanding of stem cell behavior in vitro, have provided a new impetus to study regulation and directing stem cell fate. A variety of tissue engineering technologies have been developed to regulate the fate of stem cells. Traditional methods to change the fate of stem cells are adding growth factors or some signaling pathways. In recent years, many studies have revealed that the geometrical microenvironment played an essential role in regulating the fate of stem cells, and the physical factors of scaffolds including mechanical properties, pore sizes, porosity, surface stiffness, three-dimensional structures, and mechanical stimulation may affect the fate of stem cells. Chemical factors such as cell-adhesive ligands and exogenous growth factors would also regulate the fate of stem cells. Understanding how these physical and chemical cues affect the fate of stem cells is essential for building more complex and controlled scaffolds for directing stem cell fate.

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Effect of the 3D Artificial Nichoid on the Morphology and Mechanobiological Response of Mesenchymal Stem Cells Cultured In Vitro

Cells ◽

10.3390/cells9081873 ◽

2020 ◽

Vol 9 (8) ◽

pp. 1873 ◽

Cited By ~ 3

Author(s):

Andrea Remuzzi ◽

Barbara Bonandrini ◽

Matteo Tironi ◽

Lorena Longaretti ◽

Marina Figliuzzi ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Stem Cell ◽

Cell Fate ◽

Cultured Cells ◽

Three Dimensions ◽

Nuclear Pore ◽

Cells Cultured

Stem cell fate and behavior are affected by the bidirectional communication of cells and their local microenvironment (the stem cell niche), which includes biochemical cues, as well as physical and mechanical factors. Stem cells are normally cultured in conventional two-dimensional monolayer, with a mechanical environment very different from the physiological one. Here, we compare culture of rat mesenchymal stem cells on flat culture supports and in the “Nichoid”, an innovative three-dimensional substrate micro-engineered to recapitulate the architecture of the physiological niche in vitro. Two versions of the culture substrates Nichoid (single-layered or “2D Nichoid” and multi-layered or “3D Nichoid”) were fabricated via two-photon laser polymerization in a biocompatible hybrid organic-inorganic photoresist (SZ2080). Mesenchymal stem cells, isolated from rat bone marrow, were seeded on flat substrates and on 2D and 3D Nichoid substrates and maintained in culture up to 2 weeks. During cell culture, we evaluated cell morphology, proliferation, cell motility and the expression of a panel of 89 mesenchymal stem cells’ specific genes, as well as intracellular structures organization. Our results show that mesenchymal stem cells adhered and grew in the 3D Nichoid with a comparable proliferation rate as compared to flat substrates. After seeding on flat substrates, cells displayed large and spread nucleus and cytoplasm, while cells cultured in the 3D Nichoid were spatially organized in three dimensions, with smaller and spherical nuclei. Gene expression analysis revealed the upregulation of genes related to stemness and to mesenchymal stem cells’ features in Nichoid-cultured cells, as compared to flat substrates. The observed changes in cytoskeletal organization of cells cultured on 3D Nichoids were also responsible for a different localization of the mechanotransducer transcription factor YAP, with an increase of the cytoplasmic retention in cells cultured in the 3D Nichoid. This difference could be explained by alterations in the import of transcription factors inside the nucleus due to the observed decrease of mean nuclear pore diameter, by transmission electron microscopy. Our data show that 3D distribution of cell volume has a profound effect on mesenchymal stem cells structure and on their mechanobiological response, and highlight the potential use of the 3D Nichoid substrate to strengthen the potential effects of MSC in vitro and in vivo.

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Hypoxic Culture Conditions as a Solution for Mesenchymal Stem Cell Based Regenerative Therapy

The Scientific World JOURNAL ◽

10.1155/2013/632972 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 86

Author(s):

Nazmul Haque ◽

Mohammad Tariqur Rahman ◽

Noor Hayaty Abu Kasim ◽

Aied Mohammed Alabsi

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Cell Fate ◽

Growth Kinetics ◽

Chemokine Receptors ◽

Hypoxia Inducible Factor ◽

Culture Conditions ◽

Poor Growth ◽

Regenerative Therapies

Cell-based regenerative therapies, based onin vitropropagation of stem cells, offer tremendous hope to many individuals suffering from degenerative diseases that were previously deemed untreatable. Due to the self-renewal capacity, multilineage potential, and immunosuppressive property, mesenchymal stem cells (MSCs) are considered as an attractive source of stem cells for regenerative therapies. However, poor growth kinetics, early senescence, and genetic instability duringin vitroexpansion and poor engraftment after transplantation are considered to be among the major disadvantages of MSC-based regenerative therapies. A number of complex inter- and intracellular interactive signaling systems control growth, multiplication, and differentiation of MSCs in their niche. Common laboratory conditions for stem cell culture involve ambient O2concentration (20%) in contrast to their niche where they usually reside in 2–9% O2. Notably, O2plays an important role in maintaining stem cell fate in terms of proliferation and differentiation, by regulating hypoxia-inducible factor-1 (HIF-1) mediated expression of different genes. This paper aims to describe and compare the role of normoxia (20% O2) and hypoxia (2–9% O2) on the biology of MSCs. Finally it is concluded that a hypoxic environment can greatly improve growth kinetics, genetic stability, and expression of chemokine receptors duringin vitroexpansion and eventually can increase efficiency of MSC-based regenerative therapies.

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Constructing stem cell microenvironments using bioengineering approaches

Physiological Genomics ◽

10.1152/physiolgenomics.00099.2013 ◽

2013 ◽

Vol 45 (23) ◽

pp. 1123-1135 ◽

Cited By ~ 29

Author(s):

David A. Brafman

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Cell Fate ◽

Disease Modeling ◽

Mechanical Stimuli ◽

Culture Methods ◽

Stem Cell Fate ◽

And Function

Within the adult organism, stem cells reside in defined anatomical microenvironments called niches. These architecturally diverse microenvironments serve to balance stem cell self-renewal and differentiation. Proper regulation of this balance is instrumental to tissue repair and homeostasis, and any imbalance can potentially lead to diseases such as cancer. Within each of these microenvironments, a myriad of chemical and physical stimuli interact in a complex (synergistic or antagonistic) manner to tightly regulate stem cell fate. The in vitro replication of these in vivo microenvironments will be necessary for the application of stem cells for disease modeling, drug discovery, and regenerative medicine purposes. However, traditional reductionist approaches have only led to the generation of cell culture methods that poorly recapitulate the in vivo microenvironment. To that end, novel engineering and systems biology approaches have allowed for the investigation of the biological and mechanical stimuli that govern stem cell fate. In this review, the application of these technologies for the dissection of stem cell microenvironments will be analyzed. Moreover, the use of these engineering approaches to construct in vitro stem cell microenvironments that precisely control stem cell fate and function will be reviewed. Finally, the emerging trend of using high-throughput, combinatorial methods for the stepwise engineering of stem cell microenvironments will be explored.

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Epigenetic regulation in stem cell development, cell fate conversion, and reprogramming

BioMolecular Concepts ◽

10.1515/bmc-2014-0036 ◽

2015 ◽

Vol 6 (1) ◽

pp. 1-9 ◽

Cited By ~ 5

Author(s):

Kazuyuki Ohbo ◽

Shin-ichi Tomizawa

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Transcription Factors ◽

Cell Fate ◽

Cell Lines ◽

Cell Fate Decisions ◽

Micro Rnas ◽

Stem Cell Lines ◽

Cell Fate Conversion

AbstractStem cells are identified classically by an in vivo transplantation assay plus additional characterization, such as marker analysis, linage-tracing and in vitro/ex vivo differentiation assays. Stem cell lines have been derived, in vitro, from adult tissues, the inner cell mass (ICM), epiblast, and male germ stem cells, providing intriguing insight into stem cell biology, plasticity, heterogeneity, metastable state, and the pivotal point at which stem cells irreversibly differentiate to non-stem cells. During the past decade, strategies for manipulating cell fate have revolutionized our understanding about the basic concept of cell differentiation: stem cell lines can be established by introducing transcription factors, as with the case for iPSCs, revealing some of the molecular interplay of key factors during the course of phenotypic changes. In addition to de-differentiation approaches for establishing stem cells, another method has been developed whereby induced expression of certain transcription factors and/or micro RNAs artificially converts differentiated cells from one committed lineage to another; notably, these cells need not transit through a stem/progenitor state. The molecular cues guiding such cell fate conversion and reprogramming remain largely unknown. As differentiation and de-differentiation are directly linked to epigenetic changes, we overview cell fate decisions, and associated gene and epigenetic regulations.

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MT1-MMP Plays a Critical Role in Hematopoiesis by Regulating HIF-Mediated Chemo-/Cytokine Gene Transcription within Niche Cells.

Blood ◽

10.1182/blood.v120.21.2351.2351 ◽

2012 ◽

Vol 120 (21) ◽

pp. 2351-2351

Author(s):

Chiemi Nishida ◽

Kaori Sato-Kusubata ◽

Yoshihiko Tashiro ◽

Ismael Gritli ◽

Aki Sato ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Gene Transcription ◽

Stromal Cells ◽

Stromal Cell ◽

Stem Cell Differentiation ◽

Cell Phenotype ◽

Hematopoietic Stem

Abstract Abstract 2351 Stem cells reside in a physical niche. 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 of e.g. hematopoietic stem cells (HSCs) or cancer stem cells. The bone marrow (BM) niche is a rich reservoir of tissue-specific pluripotent HSCs. Proteases such as matrix metalloproteinases (MMPs) have been implicated in cell movement, partly due to their proteolytic function, and they have been linked to cellular processes such as cell proliferation and differentiation. The proteolytic function of Membrane-type 1 MMP (MT1-MMP/MMP-14) is essential for angiogenesis, arthritis and tumour growth. Recently, it has been reported that MT1-MMP is highly expressed in HSCs and stromal/niche cells. However the clear function of MT1-MMP in hematopoiesis is not well understood. To reveal the functional consequences of MT1-MMP deficiency for post-natal hematopoiesis in vivo, we have taken advantage of MT1-MMP−/− mice to demonstrate that MT1-MMP deficiency leads to impaired steady state hematopoiesis of all hematopoietic cell lineages. In a search for factors whose deficiency could cause this hematopoietic phenotype, we found not only reduced protein release, but also reduced transcription of the following growth factors/chemokines in MT1-MMP−/− mice: erythropoietin (Epo), stromal cell-derived factor-1 (SDF-1a/CXCL12), interleukin-7 (IL-7) and Kit ligand (KitL, also known as stem cell factor). All of these factors, except for Epo, are typical stromal cell-derived factors. To ensure that impaired gene transcription in vivo was not due to a lower number of stromal cells in vivo, we demonstrated that MT1-MMP knockdown in stromal cells in vitro also reduced transcription of the stromal cell derived factors SDF-1a/CXCL12, IL-7 and KitL. In contrast, overexpression of MT1-MMP in stromal cells enhanced gene transcription of these factors. All genes, whose transcription was altered in vitro and in vivo due to MT1-MMP deficiency, had one thing in common: their gene transcription is regulated by the hypoxia inducible factor-1 (HIF-1) pathway. Further mechanistic studies revealed that MT1-MMP activates the HIF-1 pathway via factor inhibiting HIF-1 (FIH-1) within niche cells, thereby inducing the transcription of HIF-responsive genes, which induce terminal hematopoietic differentiation. Thus, MT1-MMP in niche cells regulates postnatal hematopoiesis by modulating hematopoietic HIF-dependent niche factors that are critical for terminal differentiation and migration. Disclosures: No relevant conflicts of interest to declare.

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Heightened potency of human pluripotent stem cell lines created by transient BMP4 exposure

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1504778112 ◽

2015 ◽

Vol 112 (18) ◽

pp. E2337-E2346 ◽

Cited By ~ 29

Author(s):

Ying Yang ◽

Katsuyuki Adachi ◽

Megan A. Sheridan ◽

Andrei P. Alexenko ◽

Danny J. Schust ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Cell Lines ◽

Pluripotent Stem Cells ◽

Es Cells ◽

Early Embryo ◽

Extravillous Trophoblast ◽

Cell Phenotype ◽

Small Areas

Human pluripotent stem cells (PSCs) show epiblast-type pluripotency that is maintained with ACTIVIN/FGF2 signaling. Here, we report the acquisition of a unique stem cell phenotype by both human ES cells (hESCs) and induced pluripotent stem cells (iPSCs) in response to transient (24–36 h) exposure to bone morphogenetic protein 4 (BMP4) plus inhibitors of ACTIVIN signaling (A83-01) and FGF2 (PD173074), followed by trypsin dissociation and recovery of colonies capable of growing on a gelatin substratum in standard medium for human PSCs at low but not high FGF2 concentrations. The self-renewing cell lines stain weakly for CDX2 and strongly for NANOG, can be propagated clonally on either Matrigel or gelatin, and are morphologically distinct from human PSC progenitors on either substratum but still meet standard in vitro criteria for pluripotency. They form well-differentiated teratomas in immune-compromised mice that secrete human chorionic gonadotropin (hCG) into the host mouse and include small areas of trophoblast-like cells. The cells have a distinct transcriptome profile from the human PSCs from which they were derived (including higher expression of NANOG, LEFTY1, and LEFTY2). In nonconditioned medium lacking FGF2, the colonies spontaneously differentiated along multiple lineages, including trophoblast. They responded to PD173074 in the absence of both FGF2 and BMP4 by conversion to trophoblast, and especially syncytiotrophoblast, whereas an A83-01/PD173074 combination favored increased expression of HLA-G, a marker of extravillous trophoblast. Together, these data suggest that the cell lines exhibit totipotent potential and that BMP4 can prime human PSCs to a self-renewing alternative state permissive for trophoblast development. The results may have implications for regulation of lineage decisions in the early embryo.

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

Journal of Biomedicine and Biotechnology ◽

10.1155/2012/797410 ◽

2012 ◽

Vol 2012 ◽

pp. 1-12 ◽

Cited By ~ 85

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.

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Mitochondrial Control of Stem Cell State and Fate: Lessons From Drosophila

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.606639 ◽

2021 ◽

Vol 9 ◽

Author(s):

Satish Kumar Tiwari ◽

Sudip Mandal

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Cell Fate ◽

Cell Types ◽

Extrinsic Factors ◽

Cell Fate Decisions ◽

Cell State ◽

Resident Stem Cells ◽

Stem Cell State

Over the years, Drosophila has served as a wonderful genetically tractable model system to unravel various facets of tissue-resident stem cells in their microenvironment. Studies in different stem and progenitor cell types of Drosophila have led to the discovery of cell-intrinsic and extrinsic factors crucial for stem cell state and fate. Though initially touted as the ATP generating machines for carrying various cellular processes, it is now increasingly becoming clear that mitochondrial processes alone can override the cellular program of stem cells. The last few years have witnessed a surge in our understanding of mitochondria’s contribution to governing different stem cell properties in their subtissular niches in Drosophila. Through this review, we intend to sum up and highlight the outcome of these in vivo studies that implicate mitochondria as a central regulator of stem cell fate decisions; to find the commonalities and uniqueness associated with these regulatory mechanisms.

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An in vitro stem cell model of human epiblast and yolk sac interaction

eLife ◽

10.7554/elife.63930 ◽

2021 ◽

Vol 10 ◽

Author(s):

Kirsty ML Mackinlay ◽

Bailey AT Weatherbee ◽

Viviane Souza Rosa ◽

Charlotte E Handford ◽

George Hudson ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Cell Fate ◽

Human Embryo ◽

Cell Model ◽

Embryonic Stem ◽

Yolk Sac ◽

Embryonic Cells ◽

Post Implantation

Human embryogenesis entails complex signalling interactions between embryonic and extra-embryonic cells. However, how extra-embryonic cells direct morphogenesis within the human embryo remains largely unknown due to a lack of relevant stem cell models. Here, we have established conditions to differentiate human pluripotent stem cells (hPSCs) into yolk sac-like cells (YSLCs) that resemble the post-implantation human hypoblast molecularly and functionally. YSLCs induce the expression of pluripotency and anterior ectoderm markers in human embryonic stem cells (hESCs) at the expense of mesoderm and endoderm markers. This activity is mediated by the release of BMP and WNT signalling pathway inhibitors, and, therefore, resembles the functioning of the anterior visceral endoderm signalling centre of the mouse embryo, which establishes the anterior-posterior axis. Our results implicate the yolk sac in epiblast cell fate specification in the human embryo and propose YSLCs as a tool for studying post-implantation human embryo development in vitro.

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