scholarly journals Stem Cell Niche Microenvironment: Review

2021 ◽  
Vol 8 (8) ◽  
pp. 108
Author(s):  
Mohamed Abdul-Al ◽  
George Kumi Kyeremeh ◽  
Morvarid Saeinasab ◽  
Saeed Heidari Keshel ◽  
Farshid Sefat

The cornea comprises a pool of self-regenerating epithelial cells that are crucial to preserving clarity and visibility. Limbal epithelial stem cells (LESCs), which live in a specialized stem cell niche (SCN), are crucial for the survival of the human corneal epithelium. They live at the bottom of the limbal crypts, in a physically enclosed microenvironment with a number of neighboring niche cells. Scientists also simplified features of these diverse microenvironments for more analysis in situ by designing and recreating features of different SCNs. Recent methods for regenerating the corneal epithelium after serious trauma, including burns and allergic assaults, focus mainly on regenerating the LESCs. Mesenchymal stem cells, which can transform into self-renewing and skeletal tissues, hold immense interest for tissue engineering and innovative medicinal exploration. This review summarizes all types of LESCs, identity and location of the human epithelial stem cells (HESCs), reconstruction of LSCN and artificial stem cells for self-renewal.

Stem Cells ◽  
2007 ◽  
Vol 25 (6) ◽  
pp. 1402-1409 ◽  
Author(s):  
Alex J. Shortt ◽  
Genevieve A. Secker ◽  
Peter M. Munro ◽  
Peng T. Khaw ◽  
Stephen J. Tuft ◽  
...  

2006 ◽  
Vol 290 (2) ◽  
pp. G189-G193 ◽  
Author(s):  
Neil D. Theise

This essay will address areas of liver stem/progenitor cell studies in which consensus has emerged and in which controversy still prevails over consensus, but it will also highlight important themes that inevitably should be a focus of liver stem/progenitor cell investigations in coming years. Thus concepts regarding cell plasticity, the existence of a physiological/anatomic stem cell niche, and whether intrahepatic liver stem/progenitor cells comprise true stem cells or progenitor cells (or both) will be approached in some detail.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 559-559
Author(s):  
Sarah Rivkah Vaiselbuh ◽  
Morris Edelman ◽  
Jeffrey Michael Lipton ◽  
Johnson M. Liu

Abstract Abstract 559 Introduction: Different cellular components of the normal hematopoietic niche have been identified. However, the niche for malignant hematopoiesis remains to be elucidated. Recent work of other groups has suggested that hematopoietic stem cells (HSC) within the bone marrow anchor themselves in place by attaching to osteoblasts and/or vascular sinusoid endothelial cells. We have recently identified mesenchymal stem cells (MSC) as niche-maker cells and found a crucial role of the SDF-1/CXCR4 axis in this process. Stromal Derived Factor-1 (SDF-1/CXCL12) regulates stem cell trafficking and the cell cycle via its receptor CXCR4. Methods: Polyurethane scaffolds, coated in vitro with human bone marrow MSC, were implanted subcutaneously in non-irradiated NOD/SCID mice. CD34+ HSC or primary AML cells (from a leukapheresis product) were injected either in situ or retro-orbitally in the mice and analyzed for engraftment. The mice were treated twice per week with in situ injections of SDF-1, AMD3100 (a CXCR4 antagonist) or PBS (control). After 2 to 4 weeks, the scaffolds were processed and evaluated for cell survival in the mesenchymal niche by immunohistochemistry. Results: We created in vitro MSC-coated scaffolds that retained inoculated AML cells in the presence of SDF-1, while AML cells seeded on empty scaffolds were not retained. In vivo in NOD/SCID mice, the MSC-coated scaffolds, in the presence of SDF-1 enabled homing of both in situ injected normal CD34+ HSC and retroorbital- or in situ injected primary human AML cells. The scaffolds were vascularized and showed osteoclasts and adipocytes present, suggestive of an ectopic human bone marrow microenvironment in the murine host. Finally, the SDF-1-treated scaffolds showed proliferation of the MSC stromal layer with multiple adherent AML cells, while in the AMD3100-treated scaffolds the stromal lining was thin and disrupted at several points, leaving AML cells free floating in proximity. The PBS-treated control-scaffold showed a thin single cell MSC stromal layer without disruption, with few AML cells attached. Conclusion: The preliminary data of this functional ectopic human microenvironment in NOD/SCID mice suggest that AMD3100 (a CXCR4 antagonist) can disrupt the stem cell niche by modulation of the mesenchymal stromal. Further studies are needed to define the role of mesenchymal stem cells in maintaining the hematopoietic/leukemic stem cell niche in vivo. In Vivo Leukemia Stem Cell Niche: (A) Empty polyurethane scaffold. (B)Vascularization in SQ implanted MSC-coated scaffold (s) niche in NOD/SCID mice. (C) DAB Peroxidase (brown) human CD45 positive nests of AML cells (arrows) 1 week after direct in situ AML injection. (D) Human CD45 positive myeloid cells adhere to MSC in vivo (arrows). Disclosures: No relevant conflicts of interest to declare.


2018 ◽  
Vol 29 (10) ◽  
pp. 1140-1152 ◽  
Author(s):  
Mark Basche ◽  
Daniel Kampik ◽  
Satoshi Kawasaki ◽  
Matthew J. Branch ◽  
Martha Robinson ◽  
...  

2010 ◽  
Vol 224 (3) ◽  
pp. 807-816 ◽  
Author(s):  
Young-Il Yang ◽  
Hyeong-In Kim ◽  
Min-Young Choi ◽  
Sung-Hee Son ◽  
Min-Jeong Seo ◽  
...  

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4046-4046 ◽  
Author(s):  
Michael Cross ◽  
Rudiger Alt ◽  
Lydia Schnapke-Hille ◽  
Thomas Riemer ◽  
Dietger Niederwieser

Abstract The hematopoietic stem cell niche presents a localised environment supporting the balanced maintenance, self-renewal and occasional expansion of the stem cell pool. These options are widely assumed to be regulated exclusively by signalling from specific combinations of stroma-bound or soluble ligands. However, a consideration of the rare conditions under which absolute numbers of stem cells increase in vivo as well as the selective pressures acting on regenerative systems during evolution has led us to propose a metabolic component to the stem cell niche which serves to limit cumulative damage, to avoid the selection of potentially oncogenic mutations and to tie symmetric division to slow proliferation. This would mean that traditional cell culture media based on “systemic” substrates such as glucose and glutamine may actively prevent the symmetric amplification of high quality stem cells, offering a possible explanation for the limited success in this area to date. To investigate this possibility, we have examined the effects of range of carbon and energy sources on the proliferation and maintenance of stem and progenitor cells. Our strategy is to screen a wide variety of culture conditions using murine FDCPmix cells, which are non-tumorigenic but have an innate tendency to amplify symmetrically in the presence of IL-3, and then to test key observations in human UCB CD133+ cells provided with SCF, TPO and FLT-3L. In both cell systems, we do indeed find an unusually low requirement for the systemic substrates glucose and glutamine normally included as major energy and carbon sources in cell culture media. Reducing glucose reduces the yield of committed cells from CD133+ cultures without affecting the accumulation of CD133+CD34+cKit+ progenitors. When provided with alternative substrates more likely to reflect a “niche” type environment, FDCPmix cells can be maintained for long periods in media containing only the trace levels of glucose or glutamine derived from dialysed serum, and show improved self-renewal under these conditions. We have also found that raising osmolarity reduces glucose dependence and simultaneously favours the maintenance both of self-renewing CFU (FDCPmix culture) and of CAFCweek13 (CD133+ culture). In parallel, the use of NMR and mass spectrometry techniques to profile intracellular metabolites in self-renewing and differentiating FDCPmix cells reveals a shift in the metabolite balance indicating reduced glycolysis in the early cells. Taken together, these results suggest that hematopoietic stem cells do indeed have remarkable metabolic characteristics consistent with adaptation to a metabolically limiting niche environment. It may therefore be necessary to identify niche substrates and to combine these with the relevant signalling environment in vitro in order to effectively increase stem cell numbers for research, stem cell transplantation and tissue engineering applications.


2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
M. Notara ◽  
A. Lentzsch ◽  
M. Coroneo ◽  
C. Cursiefen

The cornea is a clear structure, void of blood, and lymphatic vessels, functioning as our window to the world. Limbal epithelial stem cells, occupying the area between avascular cornea and vascularized conjunctiva, have been implicated in tissue border maintenance, preventing conjunctivalisation and propagation of blood and lymphatic vessels into the cornea. Defects in limbal epithelial stem cells are linked to corneal neovascularisation, including lymphangiogenesis, chronic inflammation, conjunctivalisation, epithelial abnormalities including the presence of goblet cells, breaks in Bowman’s membrane, persistent epithelial defects and ulceration, ocular surface squamous neoplasia, lipid keratopathy, pain, discomfort, and compromised vision. It has been postulated that pterygium is an example of focal limbal deficiency. Previous reports showing changes occurring in limbal epithelium during pterygium pathogenesis suggest that there is a link to stem cell damage. In this light, pterygium can serve as a model disease of UV-induced stem cell damage also characterised by corneal blood and lymphangiogenesis. This review focuses on the role of corneal and limbal epithelial cells and the stem cell niche in maintaining corneal avascularity and corneal immune privilege and how this may be deregulated following UV exposure. We present an overview of the PUBMED literature in the field as well as recent work from our laboratories.


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