scholarly journals The FlatwormMacrostomum lignanoIs a Powerful Model Organism for Ion Channel and Stem Cell Research

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Daniil Simanov ◽  
Imre Mellaart-Straver ◽  
Irina Sormacheva ◽  
Eugene Berezikov
Keyword(s):  
Stem Cell ◽  
Membrane Potential ◽  
Ion Channels ◽  
Cell Activity ◽  
Model Organism ◽  
Membrane Potentials ◽  
Stem Cell Maintenance ◽  
Cellular Processes ◽  
Proliferation And Differentiation ◽  
Voltage Gradients

Bioelectrical signals generated by ion channels play crucial roles in many cellular processes in both excitable and nonexcitable cells. Some ion channels are directly implemented in chemical signaling pathways, the others are involved in regulation of cytoplasmic or vesicular ion concentrations, pH, cell volume, and membrane potentials. Together with ion transporters and gap junction complexes, ion channels form steady-state voltage gradients across the cell membranes in nonexcitable cells. These membrane potentials are involved in regulation of such processes as migration guidance, cell proliferation, and body axis patterning during development and regeneration. While the importance of membrane potential in stem cell maintenance, proliferation, and differentiation is evident, the mechanisms of this bioelectric control of stem cell activity are still not well understood, and the role of specific ion channels in these processes remains unclear. Here we introduce the flatwormMacrostomum lignanoas a versatile model organism for addressing these topics. We discuss biological and experimental properties ofM. lignano, provide an overview of the recently developed experimental tools for this animal model, and demonstrate how manipulation of membrane potential influences regeneration inM. lignano.

Dynamic Mechanical Properties Control Adult Stem Cell Fate

2012 ◽  
Author(s):  
Murat Guvendiren ◽  
Jason A. Burdick
Keyword(s):  
Stem Cell ◽  
Cell Fate ◽  
Adult Stem Cell ◽  
Dynamic Mechanical Properties ◽  
Cellular Functions ◽  
Cellular Processes ◽  
Proliferation And Differentiation ◽  
Important Field ◽  
Control Adult

Stem cells respond to many microenvironmental cues towards their decisions to spread, migrate, and differentiate and these cues can be incorporated into materials for regenerative medicine.1 In the last decade, matrix stiffness alone has been implicated in regulating cellular functions such as migration, proliferation and differentiation. With this in mind, a variety of natural and synthetic polymer systems were used in vitro to mimic the elasticity of native tissues. Despite helping to develop this important field and gather valuable information, these substrates are primarily static and lack the dynamic nature that is observed during many cellular processes such as development, fibrosis and cancer. Thus, it is of great interest to temporally manipulate matrix elasticity in vitro to better understand and develop strategies to control these biological processes. In this work, we utilize a sequential crosslinking approach (initial gelation via addition reaction, secondary crosslinking through light-mediated radical polymerization) to fabricate hydrogel substrates that stiffen (e.g., ∼3 to 30 kPa) either immediately or at later times and in the presence of cells. We demonstrate the utility of this technique by investigating the short-term (several minutes to hours) and long-term (several days to weeks) stem cell response to dynamic stiffening

scholarly journals mastermind regulates niche ageing independently of the Notch pathway in the Drosophila ovary

Open Biology ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 190127
Author(s):  
María Lobo-Pecellín ◽  
Miriam Marín-Menguiano ◽  
Acaimo González-Reyes
Keyword(s):  
Stem Cell ◽  
Cell Activity ◽  
Notch Pathway ◽  
Tissue Homeostasis ◽  
Germline Stem Cells ◽  
Proliferation And Differentiation ◽  
Stem Cell Activity ◽  
Stem Cell Populations ◽  
Drosophila Ovary ◽  
Systemic Signals

Proper stem cell activity in tissues ensures the correct balance between proliferation and differentiation, thus allowing tissue homeostasis and repair. The Drosophila ovary develops well-defined niches that contain on average 2–4 germline stem cells (GSCs), whose maintenance depends on systemic signals and local factors. A known player in the decline of tissue homeostasis is ageing, which correlates with the waning of resident stem cell populations. In Drosophila , ovaries from old females contain fewer GSCs than those from young flies. We isolated niche cells of aged ovaries, performed a transcriptomic analysis and identified mastermind (mam) as a factor for Drosophila ovarian niche functionality during ageing. We show that mam is upregulated in aged niche cells and that we can induce premature GSC loss by overexpressing mam in otherwise young niche cells. High mam levels in niche cells induce reduced Hedgehog amounts, a decrease in cadherin levels and a likely increase in reactive oxygen species, three scenarios known to provoke GSC loss. Mam is a canonical co-activator of the Notch pathway in many Drosophila tissues. However, we present evidence to support a Notch-independent role for mam in the ovarian germline niche.

scholarly journals Regulation of Drosophila Intestinal Stem Cell Maintenance and Proliferation

2015 ◽  
Vol 2 (1) ◽  
pp. 77-84
Author(s):  
Olha Strilbytska
Keyword(s):  
Stem Cell ◽  
Signaling Pathways ◽  
Intestinal Stem Cells ◽  
Stem Cell Maintenance ◽  
Intestinal Integrity ◽  
Proliferation And Differentiation ◽  
Gut Homeostasis ◽  
Multiple Signaling ◽  
Adult Drosophila ◽  
Cell Maintenance

To maintain gut homeostasis intestinal stem cells (ISCs) constantly replace damagedones. This process is conservative from Drosophila to human. Proliferation and differentiation ofISCs in adult Drosophila midgut are regulated by growth factors which are secreted in thesurrounding cells collectively forming ISCs niche. Here I discuss an interaction between ISCs withits niche through conservative signaling pathways. Several evidences on significance ofcooperation between multiple signaling pathways including Notch, Wingless, JAK/STAT, EGFR,Hippo, and insulin signaling for regulation of stem cell maintenance and activity are provided.Further investigation in this area will allow us to understand how proper regulation of ISCsmaintenance and differentiation can assist to ensure intestinal integrity

scholarly journals Integration of pluripotency pathways regulates stem cell maintenance in theArabidopsisshoot meristem

2020 ◽  
Vol 117 (36) ◽  
pp. 22561-22571 ◽  
Author(s):  
Ying Hua Su ◽  
Chao Zhou ◽  
Ying Ju Li ◽  
Yang Yu ◽  
Li Ping Tang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Expression Patterns ◽  
Cell Activity ◽  
Direct Interaction ◽  
Shoot Meristem ◽  
Stem Cell Maintenance ◽  
Spatiotemporal Expression ◽  
Undifferentiated State ◽  
Stem Cell Activity

In the shoot meristem, both WUSCHEL (WUS) and SHOOT MERISTEMLESS (STM), two transcription factors with overlapping spatiotemporal expression patterns, are essential for maintaining stem cells in an undifferentiated state. Despite their importance, it remains unclear how these two pathways are integrated to coordinate stem cell development. Here, we show that the WUS and STM pathways inArabidopsis thalianaconverge through direct interaction between the WUS and STM proteins. STM binds to the promoter ofCLAVATA3(CLV3) and enhances the binding of WUS to the same promoter through the WUS–STM interaction. Both the heterodimerization and simultaneous binding of WUS and STM at two sites on theCLV3promoter are required to regulateCLV3expression, which in turn maintains a constant number of stem cells. Furthermore, the expression ofSTMdepends on WUS, and this WUS-activatedSTMexpression enhances the WUS-mediated stem cell activity. Our data provide a framework for understanding how spatial expression patterns within the shoot meristem are translated into regulatory units of stem cell homeostasis.

scholarly journals Chemoresistance, Cancer Stem Cells, and miRNA Influences: The Case for Neuroblastoma

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Alfred Buhagiar ◽  
Duncan Ayers
Keyword(s):  
Stem Cell ◽  
Basic Research ◽  
Sympathetic Ganglia ◽  
The Body ◽  
Nerve Tissue ◽  
Diagnostic Tools ◽  
Stem Cell Maintenance ◽  
Cellular Processes ◽  
Cellular Pathways

Neuroblastoma is a type of cancer that develops most often in infants and children under the age of five years. Neuroblastoma originates within the peripheral sympathetic ganglia, with 30% of the cases developing within the adrenal medulla, although it can also occur within other regions of the body such as nerve tissue in the spinal cord, neck, chest, abdomen, and pelvis. MicroRNAs (miRNAs) regulate cellular pathways, differentiation, apoptosis, and stem cell maintenance. Such miRNAs regulate genes involved in cellular processes. Consequently, they are implicated in the regulation of a spectrum of signaling pathways within the cell. In essence, the role of miRNAs in the development of cancer is of utmost importance for the understanding of dysfunctional cellular pathways that lead to the conversion of normal cells into cancer cells. This review focuses on highlighting the recent, important implications of miRNAs within the context of neuroblastoma basic research efforts, particularly concerning miRNA influences on cancer stem cell pathology and chemoresistance pathology for this condition, together with development of translational medicine approaches for novel diagnostic tools and therapies for this neuroblastoma.

scholarly journals Bioelectric State and Cell Cycle Control of Mammalian Neural Stem Cells

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Julieta Aprea ◽  
Federico Calegari
Keyword(s):  
Stem Cells ◽  
Membrane Potential ◽  
Ion Channels ◽  
Neural Stem Cells ◽  
Current Knowledge ◽  
Cell Cycle Control ◽  
Resting Membrane Potential ◽  
Excitable Cells ◽  
Proliferation And Differentiation

The concerted action of ion channels and pumps establishing a resting membrane potential has been most thoroughly studied in the context of excitable cells, most notably neurons, but emerging evidences indicate that they are also involved in controlling proliferation and differentiation of nonexcitable somatic stem cells. The importance of understanding stem cell contribution to tissue formation during embryonic development, adult homeostasis, and regeneration in disease has prompted many groups to study and manipulate the membrane potential of stem cells in a variety of systems. In this paper we aimed at summarizing the current knowledge on the role of ion channels and pumps in the context of mammalian corticogenesis with particular emphasis on their contribution to the switch of neural stem cells from proliferation to differentiation and generation of more committed progenitors and neurons, whose lineage during brain development has been recently elucidated.

When to stop: an update on molecular mechanisms of floral meristem termination

2019 ◽  
Vol 70 (6) ◽  
pp. 1711-1718 ◽  
Author(s):  
Yifeng Xu ◽  
Nobutoshi Yamaguchi ◽  
Eng-Seng Gan ◽  
Toshiro Ito
Keyword(s):  
Stem Cell ◽  
Reproductive Success ◽  
Flower Development ◽  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Agricultural Products ◽  
Floral Meristem ◽  
Stem Cell Maintenance ◽  
Proliferation And Differentiation ◽  
Cell Maintenance

Abstract Flowers have fascinated humans for millennia, not only because of their beauty, but also because they give rise to fruits, from which most agricultural products are derived. In most angiosperms, the number and position of floral organs are morphologically and genetically defined, and their development is tightly controlled by complex regulatory networks to ensure reproductive success. How flower development is temporally initiated and spatially maintained has been widely researched. As the flower develops, the balance between proliferation and differentiation dynamically shifts towards organogenesis and termination of floral stem cell maintenance. In this review, we focus on recent findings that further reveal the intricate molecular mechanisms for precise timing of floral meristem termination.

Floral stem cells: from dynamic balance towards termination

2010 ◽  
Vol 38 (2) ◽  
pp. 613-616 ◽  
Author(s):  
Bo Sun ◽  
Toshiro Ito
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Flower Development ◽  
Dynamic Balance ◽  
Cell Activity ◽  
Fixed Number ◽  
Stem Cell Maintenance ◽  
Stem Cell Activity ◽  
Central Organ ◽  
Floral Meristems

During early flower development in Arabidopsis, floral stem cells proliferate and produce a sufficient amount of cells that are recruited for organogenesis. However, after the central organ primordia initiate, stem cell activity in the floral meristem is terminated to ensure the differentiation of a fixed number of floral organs. Underlying this process, the genetic programme regulating the fate of floral meristems undergoes a shift from a spatially balanced signalling scheme for stem cell maintenance to a temporally controlled transcriptional scheme for stem cell termination. Precise timing of stem cell termination is a key issue for flower development, which is secured by the orchestration of multiple regulators in transcriptional and epigenetic regulation.

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