The stem cell system in demosponges: suggested involvement of two types of cells: archeocytes (active stem cells) and choanocytes (food-entrapping flagellated cells)

2012 ◽  
Vol 223 (1-2) ◽  
pp. 23-38 ◽  
Author(s):  
Noriko Funayama
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell System ◽  
Stem Cell System

scholarly journals Aging germline stem cells in C. elegans

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 740-740
Author(s):  
E Jane Hubbard
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell System ◽  
Cell Aging ◽  
Germline Stem Cell ◽  
Germline Stem Cells ◽  
C Elegans ◽  
Cell Pool ◽  
Stem Cell System ◽  
Stem Cell Pool

Abstract Failure to maintain stem cells with age is associated with conditions such as tissue degeneration and increased susceptibility to tissue damage. We use the C. elegans germline stem cell system as a model to study stem cell aging. This system combines a well-established model for aging with an accessible stem cell system, providing a unique opportunity to understand how aging influences stem cell dynamics. The germline stem/progenitor pool in in C. elegans becomes depleted over time. At the cellular level, aging influences both the size of the stem cell pool and the proliferation rate of stem cells. The flux of differentiated cells also affects how aging impacts the pool. This depletion is partially alleviated in mutants with reduced insulin/IGF-like signaling via inhibition of the transcription factor DAF-16/FOXO. In this role, DAF-16 does not act in the germ line, and its anatomical requirements are different from its previously described roles in larval germline proliferation, dauer control, and lifespan regulation. We found that DAF-16/FOXO is required in certain somatic cells in the proximal part of the reproductive system to regulate the stem cell pool. We also find that the degree to which various age-defying perturbations affect lifespan does not correlate with their effect on germline stem cell maintenance. We are investigating additional aspects of aging germline stem cells using this system.

scholarly journals Tissue Stem Cells of the Human Vocal Fold Mucosa and Their Stem Cell System

2020 ◽  
Vol 32 (02) ◽  
pp. 93-98
Author(s):  
Kiminori Sato ◽  
Shun-ichi Chitose ◽  
Fumihiko Sato ◽  
Kiminobu Sato ◽  
Takashi Kurita ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Vocal Fold ◽  
Cell System ◽  
Stem Cell System

scholarly journals WUSCHEL acts as an auxin response rheostat to maintain apical stem cells in Arabidopsis

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yanfei Ma ◽  
Andrej Miotk ◽  
Zoran Šutiković ◽  
Olga Ermakova ◽  
Christian Wenzl ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell System ◽  
Auxin Signaling ◽  
Stable Gene ◽  
Stem Cell System ◽  
Plant Stem ◽  
Low Levels ◽  
Stable Gene Expression

Abstract To maintain the balance between long-term stem cell self-renewal and differentiation, dynamic signals need to be translated into spatially precise and temporally stable gene expression states. In the apical plant stem cell system, local accumulation of the small, highly mobile phytohormone auxin triggers differentiation while at the same time, pluripotent stem cells are maintained throughout the entire life-cycle. We find that stem cells are resistant to auxin mediated differentiation, but require low levels of signaling for their maintenance. We demonstrate that the WUSCHEL transcription factor confers this behavior by rheostatically controlling the auxin signaling and response pathway. Finally, we show that WUSCHEL acts via regulation of histone acetylation at target loci, including those with functions in the auxin pathway. Our results reveal an important mechanism that allows cells to differentially translate a potent and highly dynamic developmental signal into stable cell behavior with high spatial precision and temporal robustness.

Elimination of both cancer stem cells and progenitor cells as essential for tumor eradication.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e22179-e22179
Author(s):  
Creticus Petrov Marak ◽  
Achuta Kumar Guddati
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cancer Stem Cells ◽  
Progenitor Cells ◽  
Cell System ◽  
Differentiated Cells ◽  
Differentiating Agents ◽  
Stem Cell System ◽  
Tumor Eradication ◽  
Stem Cell Pool

e22179 Background: Cancer stem cells (CSC) have been identified in several malignancies. Elimination of CSCs requires precise identification of markers and development of mechanisms to target them specifically. It is possible that in spite of elimination of CSCs, the tumor may recur. Dedifferentiation of progenitor cells may help replenish cancer stem cells. Methods: A mathematical model of a cancer stem cell system with four layers has been constructed to reflect the hierarchy of cancer stem cells, progenitor cells and, transit-amplifying cells and pre-differentiated cells. This model is constructed in the lines of the phase space model described by Kirkland. Dedifferentiation parameters were introduced to allow for dedifferentiation when the stem cell pool receded below 40% of its normal size. The effects of stem cell antagonists (SCA) and differentiating agents (DA) were simulated to study the perturbations caused by them on the growth of the tumor. Results: SCAs when used alone result in the establishment of a new equilibrium across different layers within the tumor by de-differentiation. DAs which act only on progenitor cells cause an increase in the number of cells in the subsequent layers and contribute to an increase in the size of the tumor. DAs which act only on the pre-differentiated layer of cells move cells from this layer into a terminally differentiated layer of cells which results in a new but lower equilibrium. DAs which act on the progenitor, transit amplifying and pre-differentiated cells cause the establishment of a new equilibrium which is lower than that of all agents which act on individual layers of cells. A combination of an SCA and a DA which acts on multiple layers eliminates the re-establishment of a new equilibrium and leads to decline in cell populations in all the layers, thus reducing the possibility of recurrence. Conclusions: SCAs when used individually are not effective in eliminating the tumor. DAs which act only on progenitor cells can fuel tumor growth but DAs which act on multiple layers have a profound effect in slowing the growth of the tumor but do not eliminate the tumor. This model implies that a combination of an SCA and a DA which acts on multiple layers may have a better chance at eliminating the tumor.

scholarly journals WUSCHEL acts as a rheostat on the auxin pathway to maintain apical stem cells in Arabidopsis

2018 ◽  
Author(s):  
Yanfei Ma ◽  
Andrej Miotk ◽  
Zoran Šutiković ◽  
Anna Medzihradszky ◽  
Christian Wenzl ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell System ◽  
Auxin Signaling ◽  
Stable Gene ◽  
Stem Cell System ◽  
Plant Stem ◽  
Low Levels ◽  
Stable Gene Expression

ABSTRACTTo maintain the balance between long-term stem cell self-renewal and differentiation, dynamic signals need to be translated into spatially precise and temporally stable gene expression states. In the apical plant stem cell system, local accumulation of the small, highly mobile phytohormone auxin triggers differentiation while at the same time, pluripotent stem cells are maintained throughout the entire life-cycle. We find that stem cells are resistant to auxin mediated differentiation, but require low levels of signaling for their maintenance. We demonstrate that the WUSCHEL transcription factor confers this behavior by rheostatically controlling the auxin signaling and response pathway. Finally, we show that WUSCHEL acts via regulation of histone acetylation at target loci, including those with functions in the auxin pathway. Our results reveal an important mechanism that allows cells to differentially translate a potent and highly dynamic developmental signal into stable cell behavior with high spatial precision and temporal robustness.

scholarly journals Elucidating the identity and behavior of spermatogenic stem cells in the mouse testis

Reproduction ◽  
2012 ◽  
Vol 144 (3) ◽  
pp. 293-302 ◽  
Author(s):  
Shosei Yoshida
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell System ◽  
Tissue Architecture ◽  
Universal Principle ◽  
Single Cell Suspension ◽  
Daughter Cells ◽  
Classical Models ◽  
Stem Cell System ◽  
And Behavior

Spermatogenesis in mice and other mammalians is supported by a robust stem cell system. Stem cells maintain themselves and continue to produce progeny that will differentiate into sperm over a long period. The pioneering studies conducted from the 1950s to the 1970s, which were based largely on extensive morphological analyses, have established the fundamentals of mammalian spermatogenesis and its stem cells. The prevailing so-called Asingle (As) model, which was originally established in 1971, proposes that singly isolated As spermatogonia are in fact the stem cells. In 1994, the first functional stem cell assay was established based on the formation of repopulating colonies after transplantation in germ cell-depleted host testes, which substantially accelerated the understanding of spermatogenic stem cells. However, because testicular tissues are dissociated into single-cell suspension before transplantation, it was impossible to evaluate the As and other classical models solely by this technique. From 2007 onwards, functional assessment of stem cells without destroying the tissue architecture has become feasible by means of pulse-labeling and live-imaging strategies. Results obtained from these experiments have been challenging the classical thought of stem cells, in which stem cells are a limited number of specialized cells undergoing asymmetric division to produce one self-renewing and one differentiating daughter cells. In contrast, the emerging data suggest that an extended and heterogeneous population of cells exhibiting different degrees of self-renewing and differentiating probabilities forms a reversible, flexible, and stochastic stem cell system as a population. These features may lead to establishment of a more universal principle on stem cells that is shared by other systems.

scholarly journals Decoding the Regulatory Logic of the Drosophila Male Stem Cell System

Cell Reports ◽  
2018 ◽  
Vol 24 (11) ◽  
pp. 3072-3086 ◽  
Author(s):  
Srividya Tamirisa ◽  
Fani Papagiannouli ◽  
Eugen Rempel ◽  
Olga Ermakova ◽  
Nils Trost ◽  
...  
Keyword(s):  
Stem Cell ◽  
Cell System ◽  
Stem Cell System

scholarly journals A novel self-organizing embryonic stem cell system reveals signaling logic underlying the patterning of human ectoderm

Development ◽  
2019 ◽  
Vol 146 (20) ◽  
pp. dev179093 ◽  
Author(s):  
George Britton ◽  
Idse Heemskerk ◽  
Rachel Hodge ◽  
Amina A. Qutub ◽  
Aryeh Warmflash
Keyword(s):  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Embryonic Stem ◽  
Cell System ◽  
Stem Cell System ◽  
Self Organizing
Sign in / Sign up

Export Citation Format

Share Document