scholarly journals A model of protein interactions for regulating plant stem cells

2017 ◽  
Author(s):  
Jérémy Gruel ◽  
Julia Deichmann ◽  
Benoit Landrein ◽  
Thomas Hitchcock ◽  
Henrik Jönsson
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Protein Interactions ◽  
Stem Cell Niche ◽  
Apical Meristem ◽  
Stem Cell Marker ◽  
Tissue Size ◽  
Plant Stem ◽  
Cell Niche ◽  
Plant Stem Cells

AbstractThe plant shoot apical meristem holds a stem cell niche from which all aerial organs originate. Using a computational approach we show that a mixture of monomers and heterodimers of the transcription factors WUSCHEL and HAIRY MERISTEM is sufficient to pattern the stem cell niche, and predict that immobile heterodimers form a regulatory ‘pocket’ surrounding the stem cells. The model achieves to reproduce an array of perturbations, including mutants and tissue size modifications. We also show its ability to reproduce the recently observed dynamical shift of the stem cell niche during the development of an axillary meristem. The work integrates recent experimental results to answer the longstanding question of how the asymmetry of expression between the stem cell marker CLAVATA3 and its activator WUSCHEL is achieved, and recent findings of plasticity in the system.

scholarly journals Immunostaining of Lgr5, an Intestinal Stem Cell Marker, in Normal and Premalignant Human Gastrointestinal Tissue

2008 ◽  
Vol 8 ◽  
pp. 1168-1176 ◽  
Author(s):  
Laren Becker ◽  
Qin Huang ◽  
Hiroshi Mashimo
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Stem Cell Niche ◽  
Intestinal Stem Cells ◽  
Stem Cell Marker ◽  
Tumor Initiating Cells ◽  
Colonic Adenomas ◽  
Potential Marker ◽  
Cell Niche ◽  
Crypt Base

Lgr5 has recently been identified as a murine marker of intestinal stem cells. Its expression has not been well characterized in human gastrointestinal tissues, but has been reported in certain cancers. With the increasing appreciation for the role of cancer stem cells or tumor-initiating cells in certain tumors, we sought to explore the expression of Lgr5 in normal and premalignant human gastrointestinal tissues. Using standard immunostaining, we compared expression of Lgr5 in normal colon and small intestine vs. small intestinal and colonic adenomas and Barrett's esophagus. In the normal tissue, Lgr5 was expressed in the expected stem cell niche, at the base of crypts, as seen in mice. However, in premalignant lesions, Lgr5+cells were not restricted to the crypt base. Additionally, their overall numbers were increased. In colonic adenomas, Lgr5+cells were commonly found clustered at the luminal surface and rarely at the crypt base. Finally, we compared immunostaining of Lgr5 with that of CD133, a previously characterized marker for tumor-initiating cells in colon cancer, and found that they identified distinct subpopulations of cells that were in close proximity, but did not costain. Our findings suggest that (1) Lgr5 is a potential marker of intestinal stem cells in humans and (2) loss of restriction to the stem cell niche is an early event in the premalignant transformation of stem cells and may play a role in carcinogenesis.

The quiescent centre of the root apical meristem: Conceptual developments from Clowes to modern times

2021 ◽  
Author(s):  
Joseph G Dubrovsky ◽  
Victor B Ivanov
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Stem Cell Niche ◽  
Apical Meristem ◽  
Root Apical Meristem ◽  
Quiescent Centre ◽  
Model Species ◽  
Short Biography ◽  
Cell Niche ◽  
Over Time

Abstract In this work we discuss the concepts of the quiescent centre (QC) of the root apical meristem (RAM) and their change over time, from their formulation by F.A.L. Clowes to the present. This review is dedicated to the 100 th anniversary of the birth of Clowes, and we present his short biography and full bibliography of Clowes’ work. Over time, the concept of the QC proved to be useful for the understanding of RAM organization and behaviour. We focus specifically on conceptual developments, from the organization of the QC to understanding its functions in RAM maintenance and activity, ranging from a model species, Arabidopsis thaliana, to crops. Concepts of initial cells, stem cells, and heterogeneity of the QC cells in context of functional and structural stem cells are considered. We review the role of the QC in the context of cell flux in the RAM and the nature of quiescence of the QC cells. We discuss the origin of the QC and fluctuation of its size in ontogenesis and why the QC cells are more resistant to stress. Contemporary concepts of organizer and stem cell niche are also considered. We also propose how the stem cell niche in the RAM can be defined in roots of a non-model species.

scholarly journals An epidermis-driven mechanism positions and scales stem cell niches in plants

2016 ◽  
Vol 2 (1) ◽  
pp. e1500989 ◽  
Author(s):  
Jérémy Gruel ◽  
Benoit Landrein ◽  
Paul Tarr ◽  
Christoph Schuster ◽  
Yassin Refahi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cell ◽  
Stem Cell Niche ◽  
Apical Meristem ◽  
De Novo ◽  
Molecular Patterning ◽  
Plant Stem ◽  
Cell Niche ◽  
Stem Cell Niches ◽  
Epidermal Cell Layer

How molecular patterning scales to organ size is highly debated in developmental biology. We explore this question for the characteristic gene expression domains of the plant stem cell niche residing in the shoot apical meristem. We show that a combination of signals originating from the epidermal cell layer can correctly pattern the key gene expression domains and notably leads to adaptive scaling of these domains to the size of the tissue. Using live imaging, we experimentally confirm this prediction. The identified mechanism is also sufficient to explain de novo stem cell niches in emerging flowers. Our findings suggest that the deformation of the tissue transposes meristem geometry into an instructive scaling and positional input for the apical plant stem cell niche.

Tissue Stem Cells and Stem Cell Niche of the Human Vocal Fold

2020 ◽  
Vol 71 (2) ◽  
pp. 211-213
Author(s):  
K. Sato ◽  
S. Chitose ◽  
K. Sato ◽  
F. Sato ◽  
T. Kurita ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Stem Cell Niche ◽  
Vocal Fold ◽  
Cell Niche

scholarly journals Understanding the Influence of Substrate When Growing Tumorspheres

2020 ◽  
Author(s):  
Lucía Benítez ◽  
Lucas Barberis ◽  
Luciano Vellón ◽  
Carlos Alberto Condat
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Growth Factors ◽  
Cell Growth ◽  
Cancer Stem Cells ◽  
Cancer Stem Cell ◽  
Stem Cell Niche ◽  
Cell Number ◽  
Hard Substrate ◽  
Cell Niche

Abstract Background: Cancer stem cells are important for the development of many solid tumors. These cells receive promoting and inhibitory signals that depend on the nature of their environment (their niche) and determine cell dynamics. Mechanical stresses are crucial to the initiation and interpretation of these signals. Methods: A two-population mathematical model of tumorsphere growth is used to interpret the results of a series of experiments recently carried out in Tianjin, China, and extract information about the intraspecific and interspecific interactions between cancer stem cell and differentiated cancer cell populations. Results: The model allows us to reconstruct the time evolution of the cancer stem cell fraction, which was not directly measured. We find that, in the presence of stem cell growth factors, the interspecific cooperation between cancer stem cells and differentiated cancer cells induces a positive feedback loop that determines growth, independently of substrate hardness. In a frustrated attempt to reconstitute the stem cell niche, the number of cancer stem cells increases continuously with a reproduction rate that is enhanced by a hard substrate. For growth on soft agar, intraspecific interactions are always inhibitory, but on hard agar the interactions between stem cells are collaborative while those between differentiated cells are strongly inhibitory. Evidence also suggests that a hard substrate brings about a large fraction of asymmetric stem cell divisions. In the absence of stem cell growth factors, the barrier to differentiation is broken and overall growth is faster, even if the stem cell number is conserved. Conclusions: Our interpretation of the experimental results validates the centrality of the concept of stem cell niche when tumor growth is fueled by cancer stem cells. Niche memory is found to be responsible for the characteristic population dynamics observed in tumorspheres. A specific condition for the growth of the cancer stem cell number is also obtained.

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