Meristems, Stem Cells, and Stem Cell Niches in Vascular Land Plants

Two distinct stem/progenitor cell populations of biliary origin have been identified in the adult liver and biliary tree. Hepatic Stem/progenitor Cells (HpSCs) are bipotent progenitor cells located within the canals of Hering and can be differentiated into mature hepatocytes and cholangiocytes; Biliary Tree Stem/progenitor Cells (BTSCs) are multipotent stem cells located within the peribiliary glands of large intrahepatic and extrahepatic bile ducts and able to differentiate into hepatic and pancreatic lineages. HpSCs and BTSCs are endowed in a specialized niche constituted by supporting cells and extracellular matrix compounds. The actual contribution of these stem cell niches to liver and biliary tree homeostatic regeneration is marginal; this is due to the high replicative capabilities and plasticity of mature parenchymal cells (i.e., hepatocytes and cholangiocytes). However, the study of human liver and biliary diseases disclosed how these stem cell niches are involved in the regenerative response after extensive and/or chronic injuries, with the activation of specific signaling pathways. The present review summarizes the contribution of stem/progenitor cell niches in human liver diseases, underlining mechanisms of activation and clinical implications, including fibrogenesis and disease progression.

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Designing stem cell niches for differentiation and self-renewal

Journal of The Royal Society Interface ◽

10.1098/rsif.2018.0388 ◽

2018 ◽

Vol 15 (145) ◽

pp. 20180388 ◽

Cited By ~ 35

Author(s):

Hannah Donnelly ◽

Manuel Salmeron-Sanchez ◽

Matthew J. Dalby

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Regenerative Medicine ◽

Regulatory Networks ◽

Regulatory Mechanisms ◽

Great Promise ◽

Regenerative Capacity ◽

Cell Niche ◽

Stem Cell Niches

Mesenchymal stem cells, characterized by their ability to differentiate into skeletal tissues and self-renew, hold great promise for both regenerative medicine and novel therapeutic discovery. However, their regenerative capacity is retained only when in contact with their specialized microenvironment, termed the stem cell niche . Niches provide structural and functional cues that are both biochemical and biophysical, stem cells integrate this complex array of signals with intrinsic regulatory networks to meet physiological demands. Although, some of these regulatory mechanisms remain poorly understood or difficult to harness with traditional culture systems. Biomaterial strategies are being developed that aim to recapitulate stem cell niches, by engineering microenvironments with physiological-like niche properties that aim to elucidate stem cell-regulatory mechanisms, and to harness their regenerative capacity in vitro . In the future, engineered niches will prove important tools for both regenerative medicine and therapeutic discoveries.

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Spatial Distributions, Characteristics, and Applications of Craniofacial Stem Cells

Stem Cells International ◽

10.1155/2020/8868593 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Geru Zhang ◽

Qiwen Li ◽

Quan Yuan ◽

Shiwen Zhang

Keyword(s):

Stem Cells ◽

Spatial Distribution ◽

Stem Cell ◽

Cranial Sutures ◽

Stem Cell Markers ◽

Spatial Distributions ◽

Self Renewal ◽

Stem Cell Niches ◽

Multidirectional Differentiation

Stem cells play an irreplaceable role in the development, homeostasis, and regeneration of the craniofacial bone. Multiple populations of tissue-resident craniofacial skeletal stem cells have been identified in different stem cell niches, including the cranial periosteum, jawbone marrow, temporomandibular joint, cranial sutures, and periodontium. These cells exhibit self-renewal and multidirectional differentiation abilities. Here, we summarized the properties of craniofacial skeletal stem cells, based on their spatial distribution. Specifically, we focused on the in vivo genetic fate mapping of stem cells, by exploring specific stem cell markers and observing their lineage commitment in both the homeostatic and regenerative states. Finally, we discussed their application in regenerative medicine.

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Hemmule: A Novel Structure with the Properties of the Stem Cell Niche

International Journal of Molecular Sciences ◽

10.3390/ijms21020539 ◽

2020 ◽

Vol 21 (2) ◽

pp. 539

Author(s):

Vitaly Vodyanoy ◽

Oleg Pustovyy ◽

Ludmila Globa ◽

Randy J. Kulesza ◽

Iryna Sorokulova

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Stem Cell ◽

Stem Cell Niche ◽

Hematopoietic Stem ◽

Novel Structure ◽

Hematopoietic Stem Cell Niches ◽

Cell Niche ◽

Stem Cell Niches ◽

Rat Bone

Stem cells are nurtured and regulated by a specialized microenvironment known as stem cell niche. While the functions of the niches are well defined, their structure and location remain unclear. We have identified, in rat bone marrow, the seat of hematopoietic stem cells—extensively vascularized node-like compartments that fit the requirements for stem cell niche and that we called hemmules. Hemmules are round or oval structures of about one millimeter in diameter that are surrounded by a fine capsule, have afferent and efferent vessels, are filled with the extracellular matrix and mesenchymal, hematopoietic, endothelial stem cells, and contain cells of the megakaryocyte family, which are known for homeostatic quiescence and contribution to the bone marrow environment. We propose that hemmules are the long sought hematopoietic stem cell niches and that they are prototypical of stem cell niches in other organs.

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Designing and Engineering Stem Cell Niches

MRS Bulletin ◽

10.1557/mrs2010.527 ◽

2010 ◽

Vol 35 (8) ◽

pp. 591-596 ◽

Cited By ~ 5

Author(s):

Ana I. Teixeira ◽

Ola Hermanson ◽

Carsten Werner

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Cell Biology ◽

Chemical Engineering ◽

Polyglycolic Acid ◽

Differentiated Cells ◽

Extracellular Matrix Components ◽

Stem Cell Niches

AbstractStem cells have received a lot of attention due to great promises in medical treatment, for example, by replacing lost and sick cells and re-constituting cell populations. There are several classes of stem cells, including embryonic, fetal, and adult tissue specific. More recently, the generation of so-called induced pluripotent stem (iPS) cells from differentiated cells has been established. Common criteria for all types of stem cells include their ability to self-renew and to retain their ability to differentiate in response to specific cues. These characteristics, as well as the instructive steering of the cells into differentiation, are largely dependent on the microenvironment surrounding the cells. Such “stem cell friendly” microenvironments, provided by structural and biochemical components, are often referred to as niches. Biomaterials offer attractive solutions to engineer functional stem cell niches and to steer stem cell state and fatein vitroas well asin vivo. Among materials used so far, promising results have been achieved with low-toxicity and biodegradable polymers, such as polyglycolic acid and related materials, as well as other polymers used as structural “scaffolds” for engineering of extracellular matrix components. To improve the efficiency of stem cell control and the design of the biomaterials, interfaces among stem cell research, developmental biology, regenerative medicine, chemical engineering, and materials research are rapidly developing. Here we provide an introduction to stem cell biology and principles of niche engineering and give an overview of recent advancements in stem cell niche engineering from two stem cell systems—blood and brain.

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Human embryonic stem cells: lessons from stem cell niches in vivo

Regenerative Medicine ◽

10.2217/17460751.3.3.365 ◽

2008 ◽

Vol 3 (3) ◽

pp. 365-376 ◽

Cited By ~ 19

Author(s):

Sean C Bendall ◽

Morag H Stewart ◽

Mickie Bhatia

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Embryonic Stem Cells ◽

Human Embryonic Stem Cells ◽

Embryonic Stem ◽

Stem Cell Niches

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Multifaced Roles of the Urokinase System in the Regulation of Stem Cell Niches

Acta Naturae ◽

10.32607/20758251-2018-10-4-19-32 ◽

2018 ◽

Vol 10 (4) ◽

pp. 19-32 ◽

Cited By ~ 2

Author(s):

K. V. Dergilev ◽

V. V. Stepanova ◽

I. B. Beloglazova ◽

Z. I. Tsokolayeva ◽

E. V. Parfenova

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Extracellular Vesicles ◽

Cell Types ◽

Biologically Active ◽

Tissue Cell ◽

Direct Cell ◽

Urokinase System ◽

And Migration ◽

Stem Cell Niches

Proliferation, subsequent migration to the damaged area, differentiation into appropriate cell types, and/or secretion of biologically active molecules and extracellular vesicles are important processes that underlie the involvement of stem/progenitor cells in the repair and regeneration of tissues and organs. All these functions are regulated through the interaction between stem cells and the microenvironment in the tissue cell niches that control these processes through direct cell-cell interactions, production of the extracellular matrix, release of extracellular vesicles, and secretion of growth factors, cytokines, chemokines, and proteases. One of the most important proteolytic systems involved in the regulation of cell migration and proliferation is the urokinase system represented by the urokinase plasminogen activator (uPA, urokinase), its receptor (uPAR), and inhibitors. This review addresses the issues of urokinase system involvement in the regulation of stem cell niches in various tissues and analyzes the possible effects of this system on the signaling pathways responsible for the proliferation, programmed cell death, phenotype modulation, and migration properties of stem cells.

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