scholarly journals Polycomb Repressive Complex(es) and Their Role in Adult Stem Cells

Genes ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1485
Author(s):  
Pooja Flora ◽  
Gil Dalal ◽  
Idan Cohen ◽  
Elena Ezhkova
Keyword(s):  
Stem Cells ◽  
Adult Stem Cells ◽  
Adult Stem Cell ◽  
Cell Types ◽  
Polycomb Group ◽  
Polycomb Repressive Complex ◽  
Cell Compartments ◽  
Adult Tissues ◽  
Resident Stem Cells ◽  
And Function

Populations of resident stem cells (SCs) are responsible for maintaining, repairing, and regenerating adult tissues. In addition to having the capacity to generate all the differentiated cell types of the tissue, adult SCs undergo long periods of quiescence within the niche to maintain themselves. The process of SC renewal and differentiation is tightly regulated for proper tissue regeneration throughout an organisms’ lifetime. Epigenetic regulators, such as the polycomb group (PcG) of proteins have been implicated in modulating gene expression in adult SCs to maintain homeostatic and regenerative balances in adult tissues. In this review, we summarize the recent findings that elucidate the composition and function of the polycomb repressive complex machinery and highlight their role in diverse adult stem cell compartments.

scholarly journals Adult tissue-resident stem cells—fact or fiction?

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Deepa Bhartiya
Keyword(s):  
Stem Cells ◽  
Single Cell ◽  
Adult Stem Cells ◽  
Cell Types ◽  
Specific Cell ◽  
Tissue Specific ◽  
Cardiac Tissues ◽  
Adult Tissues ◽  
Resident Stem Cells ◽  
Abundant Cytoplasm

AbstractLife-long tissue homeostasis of adult tissues is supposedly maintained by the resident stem cells. These stem cells are quiescent in nature and rarely divide to self-renew and give rise to tissue-specific “progenitors” (lineage-restricted and tissue-committed) which divide rapidly and differentiate into tissue-specific cell types. However, it has proved difficult to isolate these quiescent stem cells as a physical entity. Recent single-cell RNAseq studies on several adult tissues including ovary, prostate, and cardiac tissues have not been able to detect stem cells. Thus, it has been postulated that adult cells dedifferentiate to stem-like state to ensure regeneration and can be defined as cells capable to replace lost cells through mitosis. This idea challenges basic paradigm of development biology regarding plasticity that a cell enters point of no return once it initiates differentiation. The underlying reason for this dilemma is that we are putting stem cells and somatic cells together while processing for various studies. Stem cells and adult mature cell types are distinct entities; stem cells are quiescent, small in size, and with minimal organelles whereas the mature cells are metabolically active and have multiple organelles lying in abundant cytoplasm. As a result, they do not pellet down together when centrifuged at 100–350g. At this speed, mature cells get collected but stem cells remain buoyant and can be pelleted by centrifuging at 1000g. Thus, inability to detect stem cells in recently published single-cell RNAseq studies is because the stem cells were unknowingly discarded while processing and were never subjected to RNAseq. This needs to be kept in mind before proposing to redefine adult stem cells.

scholarly journals Mesenchymal Stem Cells Isolated from Adipose and Other Tissues: Basic Biological Properties and Clinical Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Hakan Orbay ◽  
Morikuni Tobita ◽  
Hiroshi Mizuno
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Adult Stem Cells ◽  
Cell Types ◽  
Biological Properties ◽  
Clinical Applications ◽  
Therapeutic Tool ◽  
Adult Tissues ◽  
Clinical Benefits ◽  
Multiple Cell

Mesenchymal stem cells (MSCs) are adult stem cells that were initially isolated from bone marrow. However, subsequent research has shown that other adult tissues also contain MSCs. MSCs originate from mesenchyme, which is embryonic tissue derived from the mesoderm. These cells actively proliferate, giving rise to new cells in some tissues, but remain quiescent in others. MSCs are capable of differentiating into multiple cell types including adipocytes, chondrocytes, osteocytes, and cardiomyocytes. Isolation and induction of these cells could provide a new therapeutic tool for replacing damaged or lost adult tissues. However, the biological properties and use of stem cells in a clinical setting must be well established before significant clinical benefits are obtained. This paper summarizes data on the biological properties of MSCs and discusses current and potential clinical applications.

scholarly journals Prospects of mesenchymal stem cells in veterinary regenerative medicine and drug development

2021 ◽  
Vol 2 ◽  
pp. 2
Author(s):  
Vikash Chandra ◽  
Mudasir Bashir Gugjoo ◽  
Amarpal ◽  
G. Taru Sharma
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Stem Cell ◽  
Drug Development ◽  
Adult Stem Cells ◽  
Therapeutic Option ◽  
Embryonic Stem ◽  
Adult Stem Cell ◽  
Cell Types ◽  
Individual Development

Stem cells are wonder cells that function silently in an individual to grow and/to regenerate. There are various stem cell types; some especially embryonic stem cells (ESCs) favor individual development while more advanced cells like adult stem cells play mostly repair and tissue matrix secretion role. Among various adult stem cell types, mesenchymal stem cells play an important role to maintain tissue homeostasis. These cells are available in almost all the tissue types and exhibit features similar to the ESCs. These cells are immunoevasive, immune modulatory, and/anti-inflammatory, and bear properties of self-renewal (although limited), multiplication, and differentiation. In addition, these cells are able to migrate and home-in to the distant tissues. All these features make these cells potential candidates for therapeutic applications and drug development. There are various studies that have favored their role in therapeutics and drug development, although more studies and further insights are desired to make stem cell therapy a definitive therapeutic option.

scholarly journals GSK3β, a Master Kinase in the Regulation of Adult Stem Cell Behavior

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 225
Author(s):  
Claire Racaud-Sultan ◽  
Nathalie Vergnolle
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Adult Stem Cells ◽  
Glycogen Synthase ◽  
Inflammatory Diseases ◽  
Adult Stem Cell ◽  
Leukemic Cells ◽  
Cell Phenotype ◽  
Epithelial Regeneration ◽  
Cell Functions

In adult stem cells, Glycogen Synthase Kinase 3β (GSK3β) is at the crossroad of signaling pathways controlling survival, proliferation, adhesion and differentiation. The microenvironment plays a key role in the regulation of these cell functions and we have demonstrated that the GSK3β activity is strongly dependent on the engagement of integrins and protease-activated receptors (PARs). Downstream of the integrin α5β1 or PAR2 activation, a molecular complex is organized around the scaffolding proteins RACK1 and β-arrestin-2 respectively, containing the phosphatase PP2A responsible for GSK3β activation. As a consequence, a quiescent stem cell phenotype is established with high capacities to face apoptotic and metabolic stresses. A protective role of GSK3β has been found for hematopoietic and intestinal stem cells. Latters survived to de-adhesion through PAR2 activation, whereas formers were protected from cytotoxicity through α5β1 engagement. However, a prolonged activation of GSK3β promoted a defect in epithelial regeneration and a resistance to chemotherapy of leukemic cells, paving the way to chronic inflammatory diseases and to cancer resurgence, respectively. In both cases, a sexual dimorphism was measured in GSK3β-dependent cellular functions. GSK3β activity is a key marker for inflammatory and cancer diseases allowing adjusted therapy to sex, age and metabolic status of patients.

scholarly journals Epigenetic Regulation of Mesenchymal Stem Cells: A Focus on Osteogenic and Adipogenic Differentiation

2011 ◽  
Vol 2011 ◽  
pp. 1-18 ◽  
Author(s):  
Chad M. Teven ◽  
Xing Liu ◽  
Ning Hu ◽  
Ni Tang ◽  
Stephanie H. Kim ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Epigenetic Regulation ◽  
Adult Stem Cells ◽  
Es Cells ◽  
Adipogenic Differentiation ◽  
Embryonic Stem ◽  
Cell Types ◽  
Differentiation Potential ◽  
Msc Differentiation

Stem cells are characterized by their capability to self-renew and terminally differentiate into multiple cell types. Somatic or adult stem cells have a finite self-renewal capacity and are lineage-restricted. The use of adult stem cells for therapeutic purposes has been a topic of recent interest given the ethical considerations associated with embryonic stem (ES) cells. Mesenchymal stem cells (MSCs) are adult stem cells that can differentiate into osteogenic, adipogenic, chondrogenic, or myogenic lineages. Owing to their ease of isolation and unique characteristics, MSCs have been widely regarded as potential candidates for tissue engineering and repair. While various signaling molecules important to MSC differentiation have been identified, our complete understanding of this process is lacking. Recent investigations focused on the role of epigenetic regulation in lineage-specific differentiation of MSCs have shown that unique patterns of DNA methylation and histone modifications play an important role in the induction of MSC differentiation toward specific lineages. Nevertheless, MSC epigenetic profiles reflect a more restricted differentiation potential as compared to ES cells. Here we review the effect of epigenetic modifications on MSC multipotency and differentiation, with a focus on osteogenic and adipogenic differentiation. We also highlight clinical applications of MSC epigenetics and nuclear reprogramming.

scholarly journals Human Adult Stem Cells Maintain a Constant Phenotype Profile Irrespective of Their Origin, Basal Media, and Long Term Cultures

2015 ◽  
Vol 2015 ◽  
pp. 1-29 ◽  
Author(s):  
Indumathi Somasundaram ◽  
Rashmi Mishra ◽  
Harikrishnan Radhakrishnan ◽  
Rajkumar Sankaran ◽  
Venkata Naga Srikanth Garikipati ◽  
...  
Keyword(s):  
Stem Cells ◽  
Adult Stem Cells ◽  
Expression Profiles ◽  
Subcutaneous Fat ◽  
Adult Stem Cell ◽  
Phenotypic Marker ◽  
Human Adult ◽  
Cell Based Therapy ◽  
Basal Media

The study aims to identify the phenotypic marker expressions of different human adult stem cells derived from, namely, bone marrow, subcutaneous fat, and omentum fat, cultured in different media, namely, DMEM-Low Glucose, Alpha-MEM, DMEM-F12 and DMEM-KO and under long term culture conditions (>P20). We characterized immunophenotype by using various hematopoietic, mesenchymal, endothelial markers, and cell adhesion molecules in the long term cultures (Passages-P1, P3, P5, P9, P12, P15, and P20.) Interestingly, data revealed similar marker expression profiles irrespective of source, basal media, and extensive culturing. This demonstrates that all adult stem cell sources mentioned in this study share similar phenotypic marker and all media seem appropriate for culturing these sources. However, a disparity was observed in the markers such as CD49d, CD54, CD117, CD29, and CD106, thereby warranting further research on these markers. Besides the aforesaid objective, it is understood from the study that immunophenotyping acts as a valuable tool to identify inherent property of each cell, thereby leading to a valuable cell based therapy.

scholarly journals The evolving definition of salivary gland stem cells

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Cecilia Rocchi ◽  
Lara Barazzuol ◽  
Rob P. Coppes
Keyword(s):  
Stem Cells ◽  
Salivary Gland ◽  
Adult Stem Cell ◽  
Cell Types ◽  
Research Field ◽  
New Therapeutic Approaches ◽  
Recent Developments ◽  
Radiation Induced ◽  
Definition Of

AbstractDysfunction of the salivary gland and irreversible hyposalivation are the main side effects of radiotherapy treatment for head and neck cancer leading to a drastic decrease of the quality of life of the patients. Approaches aimed at regenerating damaged salivary glands have been proposed as means to provide long-term restoration of tissue function in the affected patients. In studies to elucidate salivary gland regenerative mechanisms, more and more evidence suggests that salivary gland stem/progenitor cell behavior, like many other adult tissues, does not follow that of the hard-wired professional stem cells of the hematopoietic system. In this review, we provide evidence showing that several cell types within the salivary gland epithelium can serve as stem/progenitor-like cells. While these cell populations seem to function mostly as lineage-restricted progenitors during homeostasis, we indicate that upon damage specific plasticity mechanisms might be activated to take part in regeneration of the tissue. In light of these insights, we provide an overview of how recent developments in the adult stem cell research field are changing our thinking of the definition of salivary gland stem cells and their potential plasticity upon damage. These new perspectives may have important implications on the development of new therapeutic approaches to rescue radiation-induced hyposalivation.

Article Commentary: Stem Cell Research in Cell Transplantation: An Analysis of Geopolitical Influence by Publications

2007 ◽  
Vol 16 (8) ◽  
pp. 867-873 ◽  
Author(s):  
David J. Eve ◽  
Paul R. Sanberg
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Transplantation ◽  
Adult Stem Cells ◽  
Adult Stem Cell ◽  
Therapeutic Area ◽  
Fetal Stem Cells ◽  
Major Player ◽  
The Us ◽  
Restricted Use

One of the fastest growing fields in researching treatments for neurodegenerative and other disorders is the use of stem cells. These cells are naturally occurring and can be obtained from three different stages of an organism's life: embryonic, fetal, and adult. In the US, political doctrine has restricted use of federal funds for stem cells, enhancing research towards an adult source. In order to determine how this legislation may be represented by the stem cell field, a retrospective analysis of stem cell articles published in the journal Cell Transplantation over a 2-year period was performed. Cell Transplantation is considered a translational journal from preclinical to clinical, so it was of interest to determine the publication outcome of stem cell articles 6 years after the US regulations. The distribution of the source of stem cells was found to be biased towards the adult stage, but relatively similar over the embryonic and fetal stages. The fetal stem cell reports were primarily neural in origin, whereas the adult stem cell ones were predominantly mesenchymal and used mainly in neural studies. The majority of stem cell studies published in Cell Transplantation were found to fall under the umbrella of neuroscience research. American scientists published the most articles using stem cells with a bias towards adult stem cells, supporting the effect of the legislation, whereas Europe was the leading continent with a bias towards embryonic and fetal stem cells, where research is “controlled” but not restricted. Japan was also a major player in the use of stem cells. Allogeneic transplants (where donor and recipient are the same species) were the most common transplants recorded, although the transplantation of human-derived stem cells into rodents was the most common specific transplantation performed. This demonstrates that the use of stem cells is an increasingly important field (with a doubling of papers between 2005 and 2006), which is likely to develop into a major therapeutic area over the next few decades and that funding restrictions can affect the type of research being performed.

Types of Stem Cells Used in US-Based Clinical Trials between 1999 and 2014

2021 ◽  
Vol 26 ◽  
pp. 169-191
Author(s):  
Emma E. Redfield ◽  
Erin K. Luciano ◽  
Monica J. Sewell ◽  
Lucas A. Mitzel ◽  
Isaac J. Sanford ◽  
...  
Keyword(s):  
Stem Cells ◽  
Clinical Trials ◽  
Stem Cell ◽  
Embryonic Stem Cells ◽  
Adult Stem Cells ◽  
Embryonic Stem ◽  
Cell Types ◽  
The Us ◽  
Health Database ◽  
Induced Pluripotent

This study looks at the number of clinical trials involving specific stem cell types. To our knowledge, this has never been done before. Stem cell clinical trials that were conducted at locations in the US and registered on the National Institutes of Health database at ‘clinicaltrials.gov’ were categorized according to the type of stem cell used (adult, cancer, embryonic, perinatal, or induced pluripotent) and the year that the trial was registered. From 1999 to 2014, there were 2,357 US stem cell clinical trials registered on ‘clinicaltrials.gov,’ and 89 percent were from adult stem cells and only 0.12 percent were from embryonic stem cells. This study concludes that embryonic stem cells should no longer be used for clinical study because of their irrelevance, moral questions, and induced pluripotent stem cells.

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