Stem cells: an origin and marks

The basic physiological functions of stem cells are given: the ability to reproduce and generate offspring, which are manifested at the level of the population, and not of a single cell. The manifestation of these functions depends on the quantitative and qualitative composition of the microenvironment. Stem cells consist of two fundamentally different types: pluripotent, which exist only in vitro (in vitro) and tissue, existing in the postpartum body (in vivo). Stem cells can be replaced without limitation in vitro and lead to the appearance of a wide range of cell types. Tissue stem cells under normal conditions do not generate cells characteristic of other types of tissue. Stem cells include cells capable of expressing the gene products characteristic of them. However, there is no universal marker to differentiate stem cells from non-stem cells. A key marker of pluripotency is the transcription factor - a pituitary-specific transcription factor is positive. A component that can be found in almost all types of stem cells is the telomerase complex. Another stem cell marker is called CD34 glycoprotein. The functional activity of stem cells is associated with a molecular marker referred to as leucine-rich repeat containing G-protein bound to receptor 5. However, other types of cells do not express this marker. The physiological capabilities of stem cells depend both on the cells themselves and on their environment. The most reliable way to identify stem cells is to determine their phenotype in vivo. This suggests that stem cells do not carry a universal molecular marker. Most likely, they have significant differences from transplanted cells, and these differences cannot always be detected in individual cells, but only at the population level.

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Postprandial transfer of colostral extracellular vesicles and their protein and miRNA cargo in neonatal calves

10.21203/rs.2.10032/v1 ◽

2019 ◽

Author(s):

Benedikt Kirchner ◽

Dominik Buschmann ◽

Vijay Paul ◽

Michael W. Pfaffl

Keyword(s):

Extracellular Vesicles ◽

Expression Profiles ◽

Bovine Milk ◽

Cell Types ◽

Specific Protein ◽

In Vivo Experiments ◽

Neonatal Calves ◽

Almost All

Abstract Background Extracellular vesicles (EVs) such as exosomes are key regulators of intercellular communication that can be found in almost all bio fluids. Although studies in the last decade have made great headway in discerning the role of EVs in many physiological and pathophysiological processes, the bioavailability and impact of dietary EVs and their cargo still remain to be elucidated. Due to its widespread consumption and high content of EV-associated microRNAs and proteins, a major focus in this field has been set on EVs in bovine milk and colostrum. Despite promising in vitro studies in recent years that show high resiliency of milk EVs to degradation and uptake of milk EV cargo in a variety of intestinal and blood cell types, in vivo experiments continue to be inconclusive and sometimes outright contradictive. Results To resolve this discrepancy, we assessed the potential postprandial transfer of colostral EVs to the circulation of newborn calves by analysing colostrum-specific protein and miRNAs, including specific isoforms (isomiRs) in cells, EV isolations and unfractionated samples from blood and colostrum. Our findings reveal distinct populations of EVs in colostrum and blood from cows that can be clearly separated by density, particle concentration and protein content (BTN1A1, MFGE8). Postprandial blood samples of calves show a time-dependent increase in EVs that share morphological and protein characteristics of colostral EVs. Analysis of miRNA expression profiles by Next-Generation Sequencing gave a different picture however. Although significant postprandial expression changes could only be detected for calf EV samples, expression profiles show very limited overlap with highly expressed miRNAs in colostral EVs or colostrum in general. Conclusions Taken together our results indicate a selective uptake of membrane-associated protein cargo but not luminal miRNAs from colostral EVs into the circulation of neonatal calves.

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Mcl-1 in Transgenic Mice Promotes Survival in a Spectrum of Hematopoietic Cell Types and Immortalization in the Myeloid Lineage

Blood ◽

10.1182/blood.v92.9.3226 ◽

1998 ◽

Vol 92 (9) ◽

pp. 3226-3239 ◽

Cited By ~ 109

Author(s):

Ping Zhou ◽

Liping Qian ◽

Christine K. Bieszczad ◽

Randolph Noelle ◽

Michael Binder ◽

...

Keyword(s):

Myeloid Cells ◽

Myeloid Cell ◽

Cell Types ◽

Cell Number ◽

Hematopoietic Cell ◽

Viable Cell Number ◽

Wide Range ◽

Transgenic Cells

Abstract Mcl-1 is a member of the Bcl-2 family that is expressed in early monocyte differentiation and that can promote viability on transfection into immature myeloid cells. However, the effects of Mcl-1 are generally short lived compared with those of Bcl-2 and are not obvious in some transfectants. To further explore the effects of this gene, mice were produced that expressed Mcl-1 as a transgene in hematolymphoid tissues. The Mcl-1 transgene was found to cause moderate viability enhancement in a wide range of hematopoietic cell types, including lymphoid (B and T) as well as myeloid cells at both immature and mature stages of differentiation. However, enhanced hematopoietic capacity in transgenic bone marrow and spleen was not reflected in any change in pool sizes in the peripheral blood. In addition, among transgenic cells, mature T cells remained long lived compared with B cells and macrophages could live longer than either of these. Interestingly, when hematopoietic cells were maintained in tissue culture in the presence of interleukin-3, Mcl-1 enhanced the probability of outgrowth of continuously proliferating myeloid cell lines. Thus, Mcl-1 transgenic cells remained subject to normal in vivo homeostatic mechanisms controlling viable cell number, but these constraints could be overridden under specific conditions in vitro. Within the organism, Bcl-2 family members may act at “viability gates” along the differentiation continuum, functioning as part of a system for controlled hematopoietic cell amplification. Enforced expression of even a moderate viability-promoting member of this family such as Mcl-1, within a conducive intra- and extracellular environment in isolation from normal homeostatic constraints, can substantially increase the probability of cell immortalization. © 1998 by The American Society of Hematology.

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Vascular Endothelial Growth Factor Inhibits the Development of Dendritic Cells and Dramatically Affects the Differentiation of Multiple Hematopoietic Lineages In Vivo

Blood ◽

10.1182/blood.v92.11.4150 ◽

1998 ◽

Vol 92 (11) ◽

pp. 4150-4166 ◽

Cited By ~ 624

Author(s):

Dmitry Gabrilovich ◽

Tadao Ishida ◽

Tsunehiro Oyama ◽

Sophia Ran ◽

Vladimir Kravtsov ◽

...

Keyword(s):

Stem Cells ◽

Vascular Endothelial Growth Factor ◽

Dendritic Cells ◽

Growth Factor ◽

System Control ◽

Vascular Endothelial ◽

Almost All ◽

Endothelial Growth Factor

Abstract Defective function of dendritic cells (DC) in cancer has been recently described and may represent one of the mechanisms of tumor evasion from immune system control. We have previously shown in vitro that vascular endothelial growth factor (VEGF), produced by almost all tumors, is one of the tumor-derived factors responsible for the defective function of these cells. In this study, we investigated whether in vivo infusion of recombinant VEGF could reproduce the observed DC dysfunction. Continuous VEGF infusion, at rates as low as 50 ng/h (resulting in serum VEGF concentrations of 120 to 160 pg/mL), resulted in a dramatic inhibition of dendritic cell development, associated with an increase in the production of B cells and immature Gr-1+ myeloid cells. Infusion of VEGF was associated with inhibition of the activity of the transcription factor NF-κB in bone marrow progenitor cells. Experiments in vitro showed that VEGF itself, and not factors released by VEGF-activated endothelial cells, affected polypotent stem cells resulting in the observed abnormal hematopoiesis. These data suggest that VEGF, at pathologically relevant concentrations in vivo, may exert effects on pluripotent stem cells that result in blocked DC development as well as affect many other hematopoietic lineages.

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Transcription factor Mohawk controls tenogenic differentiation of bone marrow mesenchymal stem cells in vitro and in vivo

Journal of Orthopaedic Research® ◽

10.1002/jor.22750 ◽

2014 ◽

Vol 33 (1) ◽

pp. 1-8 ◽

Cited By ~ 46

Author(s):

Koji Otabe ◽

Hiroyuki Nakahara ◽

Akihiko Hasegawa ◽

Tetsuya Matsukawa ◽

Fumiaki Ayabe ◽

...

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Mesenchymal Stem Cells ◽

Transcription Factor ◽

Tenogenic Differentiation ◽

Marrow Mesenchymal Stem Cells

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Modulating the Substrate Stiffness to Manipulate Differentiation of Resident Liver Stem Cells and to Improve the Differentiation State of Hepatocytes

Stem Cells International ◽

10.1155/2016/5481493 ◽

2016 ◽

Vol 2016 ◽

pp. 1-12 ◽

Cited By ~ 38

Author(s):

Angela Maria Cozzolino ◽

Valeria Noce ◽

Cecilia Battistelli ◽

Alessandra Marchetti ◽

Germana Grassi ◽

...

Keyword(s):

Stem Cells ◽

Culture Method ◽

Cell Types ◽

Culture Conditions ◽

Precursor Cells ◽

Substrate Stiffness ◽

Growth And Survival ◽

Liver Stem Cells

In many cell types, several cellular processes, such as differentiation of stem/precursor cells, maintenance of differentiated phenotype, motility, adhesion, growth, and survival, strictly depend on the stiffness of extracellular matrix that,in vivo, characterizes their correspondent organ and tissue. In the liver, the stromal rigidity is essential to obtain the correct organ physiology whereas any alteration causes liver cell dysfunctions. The rigidity of the substrate is an element no longer negligible for the cultivation of several cell types, so that many data so far obtained, where cells have been cultured on plastic, could be revised. Regarding liver cells, standard culture conditions lead to the dedifferentiation of primary hepatocytes, transdifferentiation of stellate cells into myofibroblasts, and loss of fenestration of sinusoidal endothelium. Furthermore, standard cultivation of liver stem/precursor cells impedes an efficient execution of the epithelial/hepatocyte differentiation program, leading to the expansion of a cell population expressing only partially liver functions and products. Overcoming these limitations is mandatory for any approach of liver tissue engineering. Here we propose cell lines asin vitromodels of liver stem cells and hepatocytes and an innovative culture method that takes into account the substrate stiffness to obtain, respectively, a rapid and efficient differentiation process and the maintenance of the fully differentiated phenotype.

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Aldehyde Dehydrogenases: Not Just Markers, but Functional Regulators of Stem Cells

Stem Cells International ◽

10.1155/2019/3904645 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 53

Author(s):

Giuseppe Vassalli

Keyword(s):

Stem Cells ◽

Molecular Mechanisms ◽

Cell Types ◽

Cellular Function ◽

Stem Cell Marker ◽

Cell Populations ◽

Aldh Activity ◽

Cellular Functions ◽

Stem And Progenitor Cells

Aldehyde dehydrogenase (ALDH) is a superfamily of enzymes that detoxify a variety of endogenous and exogenous aldehydes and are required for the biosynthesis of retinoic acid (RA) and other molecular regulators of cellular function. Over the past decade, high ALDH activity has been increasingly used as a selectable marker for normal cell populations enriched in stem and progenitor cells, as well as for cell populations from cancer tissues enriched in tumor-initiating stem-like cells. Mounting evidence suggests that ALDH not only may be used as a marker for stem cells but also may well regulate cellular functions related to self-renewal, expansion, differentiation, and resistance to drugs and radiation. ALDH exerts its functional actions partly through RA biosynthesis, as all-trans RA reverses the functional effects of pharmacological inhibition or genetic suppression of ALDH activity in many cell types in vitro. There is substantial evidence to suggest that the role of ALDH as a stem cell marker comes down to the specific isoform(s) expressed in a particular tissue. Much emphasis has been placed on the ALDH1A1 and ALDH1A3 members of the ALDH1 family of cytosolic enzymes required for RA biosynthesis. ALDH1A1 and ALDH1A3 regulate cellular function in both normal stem cells and tumor-initiating stem-like cells, promoting tumor growth and resistance to drugs and radiation. An improved understanding of the molecular mechanisms by which ALDH regulates cellular function will likely open new avenues in many fields, especially in tissue regeneration and oncology.

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Mesenchymal Stem Cells as a Promising Cell Source for Integration in Novel In Vitro Models

Biomolecules ◽

10.3390/biom10091306 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1306

Author(s):

Ann-Kristin Afflerbach ◽

Mark D. Kiri ◽

Tahir Detinis ◽

Ben M. Maoz

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Cell Types ◽

In Vitro Models ◽

Cell Source ◽

Fundamental Research ◽

Multiple Cell ◽

Vitro Model

The human-relevance of an in vitro model is dependent on two main factors—(i) an appropriate human cell source and (ii) a modeling platform that recapitulates human in vivo conditions. Recent years have brought substantial advancements in both these aspects. In particular, mesenchymal stem cells (MSCs) have emerged as a promising cell source, as these cells can differentiate into multiple cell types, yet do not raise the ethical and practical concerns associated with other types of stem cells. In turn, advanced bioengineered in vitro models such as microfluidics, Organs-on-a-Chip, scaffolds, bioprinting and organoids are bringing researchers ever closer to mimicking complex in vivo environments, thereby overcoming some of the limitations of traditional 2D cell cultures. This review covers each of these advancements separately and discusses how the integration of MSCs into novel in vitro platforms may contribute enormously to clinical and fundamental research.

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The impact of cryopreservation on bone marrow-derived mesenchymal stem cells: a systematic review

Journal of Translational Medicine ◽

10.1186/s12967-019-02136-7 ◽

2019 ◽

Vol 17 (1) ◽

Cited By ~ 7

Author(s):

Soukaina Bahsoun ◽

Karen Coopman ◽

Elizabeth C. Akam

Keyword(s):

Systematic Review ◽

Stem Cells ◽

Bone Marrow ◽

Mesenchymal Stem Cells ◽

Cell Types ◽

Surface Marker Expression ◽

Wide Range ◽

And Migration ◽

The Impact

AbstractMesenchymal stem cells (MSCs) represent an invaluable asset for the field of cell therapy. Human Bone marrow-derived MSCs (hBM-MSCs) are one of the most commonly used cell types in clinical trials. They are currently being studied and tested for the treatment of a wide range of diseases and conditions. The future availability of MSCs therapies to the public will require a robust and reliable delivery process. Cryopreservation represents the gold standard in cell storage and transportation, but its effect on BM-MSCs is still not well established. A systematic review was conducted to evaluate the impact of cryopreservation on BM-MSCs and to attempt to uncover the reasons behind some of the controversial results reported in the literature. Forty-one in vitro studies were analysed, and their results organised according to the cell attributes they assess. It was concluded that cryopreservation does not affect BM-MSCs morphology, surface marker expression, differentiation or proliferation potential. However, mixed results exist regarding the effect on colony forming ability and the effects on viability, attachment and migration, genomic stability and paracrine function are undefined mainly due to the huge variabilities governing the cryopreservation process as a whole and to the lack of standardised assays.

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Clonal Level Lineage Commitment of Mouse Hematopoietic Stem Cells in Vivo

Blood ◽

10.1182/blood.v120.21.27.27 ◽

2012 ◽

Vol 120 (21) ◽

pp. 27-27

Author(s):

Rong Lu ◽

Agnieszka Czechowicz ◽

Jun Seita ◽

Irving L. Weissman

Keyword(s):

Stem Cells ◽

Hematopoietic Stem Cells ◽

Cellular Proliferation ◽

Population Level ◽

Cell Types ◽

Lineage Commitment ◽

Hematopoietic Stem ◽

Clonal Level ◽

Hsc Niche

Abstract Abstract 27 Hematopoietic stem cells (HSCs) sustain the blood and immune systems through a complex differentiation process. This process involves several steps of lineage commitment and forms a paradigm for understanding cellular development, differentiation, and malignancy. While this step-wise differentiation has been extensively studied at the population level, little is known about the lineage commitment of individual HSC clones. The importance of understanding HSC differentiation at the clonal level has been raised by several recent studies suggesting that individual HSCs differentially contribute to various blood cell types and that the aggregate HSC differentiation at the population level is an amalgamation of the diverse lineage commitments of individual HSC clones. The distinct differentiation of individual HSCs may also be accentuated by their regulatory microenvironments, HSC niche. HSC niche may not affect all HSCs in an organism equally, and may instead act directly on resident HSC clones through direct contact or by tuning local cytokine concentrations. Knowledge of HSC clonal level lineage commitment will reveal new insights into HSC regulatory mechanisms and will improve our understanding of aging, immune deficiency, and many hematopoietic disorders involving an unbalanced hematopoietic system. Here, we provide a comprehensive map of in vivo HSC clonal development in mice. The clonal map was derived from the simultaneous tracking of hundreds of individual mouse HSCs in vivo using genetic barcodes. These unique barcodes were delivered into HSCs using a lentiviral vector to obtain a one-to-one mapping between barcodes and HSCs. Barcoded HSCs were then transplanted into recipient mice using standard procedures. Genetic barcodes from donor derived HSCs and their progenies were examined twenty-two weeks after transplantation using high-throughput sequencing. We found that the dominant differentiation of HSC clones is always present in pre-conditioned mice. In these recipients, a small fraction of engrafted HSCs become dominantly abundant at the intermediate progenitor stages, but not at the HSC stage. Thus, clonal dominance is a characteristic of HSC differentiation but not of HSC self-renewal. Additionally, the dominant differentiation of HSC clones exhibits distinct expansion patterns through various stages of hematopoiesis. We provide evidence that observed HSC lineage bias arises from dominant differentiation at distinct lineage commitment steps. In particular, myeloid bias arises from dominant differentiation at the first lineage commitment step from HSC to MPP, whereas lymphoid bias arises from dominant differentiation at the last lineage commitment step from CLP to B cells. We also show that dominant differentiation and lineage bias are interrelated and together delineate discrete HSC lineage commitment pathways. These pathways describe how individual HSC clones produce differential blood quantities and cell types. Multiple clonal differentiation pathways can coexist simultaneously in a single organism, and mutually compensate to sustain overall blood production. Thus, the distinct HSC differentiation characteristics uncovered by clonal analysis are not evident at the population level. We have also identified the lineage commitment profiles of HSC clones belonging to each pathway. These profiles elucidate the cellular proliferation and development of HSCs at the clonal level and demonstrate that distinct modes of HSC regulation exist in vivo. In summary, our in vivo clonal mapping reveals discrete clonal level HSC lineage commitment pathways. We have identified the cellular origins of clonal dominance and lineage bias, which may be the key hematopoietic stages where blood production and balance can be manipulated. These discoveries based on clonal level analysis are unexpected and unobtainable from conventional studies at the population level. Together, they open new avenues of research for studying hematopoiesis. Disclosures: No relevant conflicts of interest to declare.

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Mcl-1 in Transgenic Mice Promotes Survival in a Spectrum of Hematopoietic Cell Types and Immortalization in the Myeloid Lineage

Blood ◽

10.1182/blood.v92.9.3226.421k49_3226_3239 ◽

1998 ◽

Vol 92 (9) ◽

pp. 3226-3239 ◽

Cited By ~ 12

Author(s):

Ping Zhou ◽

Liping Qian ◽

Christine K. Bieszczad ◽

Randolph Noelle ◽

Michael Binder ◽

...

Keyword(s):

Myeloid Cells ◽

Myeloid Cell ◽

Cell Types ◽

Cell Number ◽

Hematopoietic Cell ◽

Viable Cell Number ◽

Wide Range ◽

Transgenic Cells

Mcl-1 is a member of the Bcl-2 family that is expressed in early monocyte differentiation and that can promote viability on transfection into immature myeloid cells. However, the effects of Mcl-1 are generally short lived compared with those of Bcl-2 and are not obvious in some transfectants. To further explore the effects of this gene, mice were produced that expressed Mcl-1 as a transgene in hematolymphoid tissues. The Mcl-1 transgene was found to cause moderate viability enhancement in a wide range of hematopoietic cell types, including lymphoid (B and T) as well as myeloid cells at both immature and mature stages of differentiation. However, enhanced hematopoietic capacity in transgenic bone marrow and spleen was not reflected in any change in pool sizes in the peripheral blood. In addition, among transgenic cells, mature T cells remained long lived compared with B cells and macrophages could live longer than either of these. Interestingly, when hematopoietic cells were maintained in tissue culture in the presence of interleukin-3, Mcl-1 enhanced the probability of outgrowth of continuously proliferating myeloid cell lines. Thus, Mcl-1 transgenic cells remained subject to normal in vivo homeostatic mechanisms controlling viable cell number, but these constraints could be overridden under specific conditions in vitro. Within the organism, Bcl-2 family members may act at “viability gates” along the differentiation continuum, functioning as part of a system for controlled hematopoietic cell amplification. Enforced expression of even a moderate viability-promoting member of this family such as Mcl-1, within a conducive intra- and extracellular environment in isolation from normal homeostatic constraints, can substantially increase the probability of cell immortalization. © 1998 by The American Society of Hematology.

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