Regeneration and pattern formation in planarians. III. that neoblasts are totipotent stem cells and the cells

Development ◽  
1989 ◽  
Vol 107 (1) ◽  
pp. 77-86 ◽  
Author(s):  
J. Baguna ◽  
E. Salo ◽  
C. Auladell
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Pattern Formation ◽  
Animal Kingdom ◽  
New Approach ◽  
Blastema Formation ◽  
Quiescent Cells ◽  
Differentiated Cells ◽  
Different Types ◽  
Undifferentiated Cells

In most regenerating systems, blastema cells arise by dedifferentiation of functional tissue cells. In is still debatable whether dedifferentiated cells or a undifferentiated cells, the neoblasts, are the main cells. Moreover, it is unclear whether in the intact neoblasts are quiescent cells ‘reserved’ for serve as functional stem cells of all differentiated uncertainties partly stem from the failure to conventional labelling methods neoblasts from Here we describe a new approach to these problems regenerative and stem cell capabilities of purified differentiated cells when introduced, separately, into hosts. Introduction of neoblasts led to resumed blastema formation, and extended or complete survival differentiated cells, in contrast, never did so. neoblasts can be qualified as totipotent stem cells of blastema cells, while dedifferentiation does not either in intact or regenerating organisms. In strengthen the idea that different types of formation, linked to the tissular complexity of the present in the animal kingdom.

scholarly journals SOX9 Stem-Cell Factor: Clinical and Functional Relevance in Cancer

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Maribel Aguilar-Medina ◽  
Mariana Avendaño-Félix ◽  
Erik Lizárraga-Verdugo ◽  
Mercedes Bermúdez ◽  
José Geovanni Romero-Quintana ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Stem Cell Factor ◽  
Current Knowledge ◽  
Functional Roles ◽  
Novel Treatments ◽  
Specific Subset ◽  
Different Types ◽  
Undifferentiated Cells ◽  
Functional Relevance

Transcriptional and epigenetic embryonic programs can be reactivated in cancer cells. As result, a specific subset of undifferentiated cells with stem-cells properties emerges and drives tumorigenesis. Recent findings have shown that ectoderm- and endoderm-derived tissues continue expressing stem-cells related transcription factors of the SOX-family of proteins such as SOX2 and SOX9 which have been implicated in the presence of cancer stem-like cells (CSCs) in tumors. Currently, there is enough evidence suggesting an oncogenic role for SOX9 in different types of human cancers. This review provides a summary of the current knowledge about the involvement of SOX9 in development and progression of cancer. Understanding the functional roles of SOX9 and clinical relevance is crucial for developing novel treatments targeting CSCs in cancer.

Stem Cells: In Sickness and in Health

2020 ◽  
Vol 15 ◽  
Author(s):  
Hisham F. Bahmada ◽  
Mohamad K. Elajami ◽  
Reem Daouk ◽  
Hiba Jalloul ◽  
Batoul Darwish ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Induced Pluripotent Stem Cell ◽  
Cell Types ◽  
Therapy Resistance ◽  
The Body ◽  
Differentiated Cells ◽  
Undifferentiated Cells ◽  
Potential Applications ◽  
Induced Pluripotent

: Stem cells are undifferentiated cells with the ability to proliferate and convert to different types of differentiated cells that make up the various tissues and organs in the body. They exist both in embryos as pluripotent stem cells that can differentiate into the three germ layers and as multipotent or unipotent stem cells in adult tissues to aid in repair and homeostasis. Perturbations in these cells’ normal functions can give rise to a wide variety of diseases. In this review, we discuss the origin of different stem cell types, their properties and characteristics, their role in tissue homeostasis, current research, and their potential applications in various life-threatening diseases. We focus on neural stem cells, their role in neurogenesis and how they can be exploited to treat diseases of the brain including neurodegenerative diseases and cancer. Next, we explore current research in induced pluripotent stem cell (iPSC) techniques and their clinical applications in regenerative and personalized medicine. Lastly, we tackle a special type of stem cells called cancer stem cells (CSCs) and how they can be responsible for therapy resistance and tumor recurrence and explore ways to target them.

scholarly journals Quiescence Entry, Maintenance, and Exit in Adult Stem Cells

2019 ◽  
Vol 20 (9) ◽  
pp. 2158 ◽  
Author(s):  
Karamat Mohammad ◽  
Paméla Dakik ◽  
Younes Medkour ◽  
Darya Mitrofanova ◽  
Vladimir I. Titorenko
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Progenitor Cells ◽  
Adult Stem Cells ◽  
Quiescent Cells ◽  
Differentiated Cells ◽  
Age Related ◽  
Different Types ◽  
Asymmetric Divisions ◽  
Multistep Process

Cells of unicellular and multicellular eukaryotes can respond to certain environmental cues by arresting the cell cycle and entering a reversible state of quiescence. Quiescent cells do not divide, but can re-enter the cell cycle and resume proliferation if exposed to some signals from the environment. Quiescent cells in mammals and humans include adult stem cells. These cells exhibit improved stress resistance and enhanced survival ability. In response to certain extrinsic signals, adult stem cells can self-renew by dividing asymmetrically. Such asymmetric divisions not only allow the maintenance of a population of quiescent cells, but also yield daughter progenitor cells. A multistep process of the controlled proliferation of these progenitor cells leads to the formation of one or more types of fully differentiated cells. An age-related decline in the ability of adult stem cells to balance quiescence maintenance and regulated proliferation has been implicated in many aging-associated diseases. In this review, we describe many traits shared by different types of quiescent adult stem cells. We discuss how these traits contribute to the quiescence, self-renewal, and proliferation of adult stem cells. We examine the cell-intrinsic mechanisms that allow establishing and sustaining the characteristic traits of adult stem cells, thereby regulating quiescence entry, maintenance, and exit.

scholarly journals me31B regulates stem cell homeostasis by preventing excess dedifferentiation in the Drosophila male germline

2021 ◽  
Author(s):  
Lindy Jensen ◽  
Zsolt G. Venkei ◽  
George J. Watase ◽  
Bitarka Bisai ◽  
Scott Pletcher ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Critical Role ◽  
Stem Cell Population ◽  
Germline Stem Cells ◽  
Cell Identity ◽  
Stem Cell Maintenance ◽  
Differentiated Cells ◽  
Male Germline ◽  
Elevated Frequency

Tissue-specific stem cells maintain tissue homeostasis by providing a continuous supply of differentiated cells throughout the life of organisms. Differentiated/differentiating cells can revert back to a stem cell identity via dedifferentiation to help maintain the stem cell pool beyond the lifetime of individual stem cells. Although dedifferentiation is important to maintain the stem cell population, it is speculated to underlie tumorigenesis. Therefore, this process must be tightly controlled. Here we show that a translational regulator me31B plays a critical role in preventing excess dedifferentiation in the Drosophila male germline: in the absence of me31B, spermatogonia (SGs) dedifferentiate into germline stem cells (GSCs) at a dramatically elevated frequency. Our results show that the excess dedifferentiation is likely due to misregulation of nos, a key regulator of germ cell identity and GSC maintenance. Taken together, our data reveal negative regulation of dedifferentiation to balance stem cell maintenance with differentiation.

Stem Cells in Neurodegenerative Disorders - A broad Overview

2021 ◽  
Author(s):  
Fariha Khaliq
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Therapy ◽  
Stem Cell Therapy ◽  
Pluripotent Stem Cells ◽  
Neurodegenerative Disorder ◽  
Human Fibroblasts ◽  
Embryonic Stem ◽  
Different Types ◽  
Induced Pluripotent

Stem cell therapy is an approach to use cells that have the ability of self-renewal and to differentiate into different types of functional cells that are obtained from embryo and other postnatal sources to treat multiple disorders. These cells can be differentiated into different types of stem cells based on their specific characteristics to be totipotent, unipotent, multipotent or pluripotent. As potential therapy, pluripotent stem cells are considered to be the most interesting as they can be differentiated into different type of cells with similar characteristics as embryonic stem cells. Induced pluripotent stem cells (iPSCs) are adult cells that are reprogrammed genetically into stem cells from human fibroblasts through expressing genes and transcription factors at different time intervals. In this review, we will discuss the applications of stem cell therapy using iPSCs technology in treating neurodegenerative disorder such that Alzheimer’s disease (AD), Parkinson’s disease (PD), and Amyotrophic Lateral Sclerosis (ALS). We have also broadly highlighted the significance of pluripotent stem cells in stem cell therapy.

Regeneration and pattern formation in planarians. II. and role of cell movements in blastema formation

Development ◽  
1989 ◽  
Vol 107 (1) ◽  
pp. 69-76 ◽  
Author(s):  
E. Salo ◽  
J. Baguna
Keyword(s):  
Pattern Formation ◽  
Cell Movement ◽  
Formation Mechanisms ◽  
Blastema Formation ◽  
Chromosomal Markers ◽  
Undifferentiated Cells ◽  
Local Cell ◽  
Number Of Cells ◽  
Wound Epithelium

In planarians, blastema cells do not divide, and growth blastema is thought to result from the steady wound epithelium, of undifferentiated cells produced in the stump. However, whether these cells come only sources or whether cells placed far from the wound can participate, after long-range migrations, in the still uncertain. To study this problem, we have parameters of the process of regeneration: cell growth; number of cells produced by mitosis in the wound (postblastema); and rates of movement undifferentiated cells using grafting procedures with chromosomal markers. The results show that: (1) cells area spread (move) at higher rates than cells placed (90–140_mday-1 versus 40–50_mday-1); (2) cells than 500_m from the wound boundary are hardly 5-day-old blastemata; and (3) the number of cells within a 200–300_m postblastema area around the wound explain, provided their rates of movement are taken increasing number of blastema cells. From this, it is blastema cells in planarians originate from local mitotic activity jointly with local cell movement postblastema area around the wound match the blastema cells during regeneration. The implications for blastema growth and pattern formation mechanisms

scholarly journals Stem Cells as a Resource for Treatment of Infertility-related Diseases

2019 ◽  
Vol 19 (8) ◽  
pp. 539-546
Author(s):  
Jing Wang ◽  
Chi Liu ◽  
Masayuki Fujino ◽  
Guoqing Tong ◽  
Qinxiu Zhang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
In Vitro Fertilization ◽  
Cell Therapy ◽  
Reproductive Medicine ◽  
Intrauterine Insemination ◽  
Reproductive Age ◽  
Vitro Fertilization ◽  
Undifferentiated Cells

Worldwide, infertility affects 8-12% of couples of reproductive age and has become a common problem. There are many ways to treat infertility, including medication, intrauterine insemination, and in vitro fertilization. In recent years, stem-cell therapy has raised new hope in the field of reproductive disability management. Stem cells are self-renewing, self-replicating undifferentiated cells that are capable of producing specialized cells under appropriate conditions. They exist throughout a human’s embryo, fetal, and adult stages and can proliferate into different cells. While many issues remain to be addressed concerning stem cells, stem cells have undeniably opened up new ways to treat infertility. In this review, we describe past, present, and future strategies for the use of stem cells in reproductive medicine.

scholarly journals Mammalian genes induce partially reprogrammed pluripotent stem cells in non-mammalian vertebrate and invertebrate species

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Ricardo Antonio Rosselló ◽  
Chun-Chun Chen ◽  
Rui Dai ◽  
Jason T Howard ◽  
Ute Hochgeschwender ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Pluripotent Stem Cells ◽  
Mammalian Species ◽  
Embryonic Stem ◽  
Model Organisms ◽  
Differentiated Cells ◽  
Transcription Factor Genes ◽  
Induced Pluripotent

Cells are fundamental units of life, but little is known about evolution of cell states. Induced pluripotent stem cells (iPSCs) are once differentiated cells that have been re-programmed to an embryonic stem cell-like state, providing a powerful platform for biology and medicine. However, they have been limited to a few mammalian species. Here we found that a set of four mammalian transcription factor genes used to generate iPSCs in mouse and humans can induce a partially reprogrammed pluripotent stem cell (PRPSCs) state in vertebrate and invertebrate model organisms, in mammals, birds, fish, and fly, which span 550 million years from a common ancestor. These findings are one of the first to show cross-lineage stem cell-like induction, and to generate pluripotent-like cells for several of these species with in vivo chimeras. We suggest that the stem-cell state may be highly conserved across a wide phylogenetic range.

Maintenance of Pluripotent Stem Cells is Influenced by Ser/Thr Metabolism

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. SCI-43-SCI-43
Author(s):  
Lewis C. Cantley
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Embryonic Stem ◽  
Isocitrate Dehydrogenase 1 ◽  
Advisory Committees ◽  
Metabolic Intermediates ◽  
Stem Cell Maintenance ◽  
Differentiated Cells ◽  
Methylation Of Dna

Abstract Recent studies have suggested not only that stem cells have different metabolic requirements than terminally differentiated cells, but also that metabolic intermediates may play a role in the maintenance of stem cells. It has long been clear that changes in acetylation and methylation of histones, as well as methylation of DNA play critical roles in deciding cell fate. The availability of critical intermediates in metabolism, especially S-adenosylmethionine (SAM), acetyl-CoA, nicotinamide adenine dinucleotide (NAD) and a-ketoglutarate play critical roles in modulating acetylation and methylation of histones and methylation of DNA. In the course of evaluating an unusual requirement of threonine (Thr) for the growth of murine embryonic stem cells, we found that metabolism of Thr to glycine (Gly) and the subsequent use of the methyl group of Gly for converting homocysteine to methionine is critical for maintaining high levels of SAM and low levels of S-adenosyl-homocysteine. Importantly, depletion of Thr from the media resulted in decreased tri-methylation of histone H3 lysine-4 (H3K4me3), leading to slowed growth and increased differentiation. Thus, abundance of SAM appears to influence H3K4me3, providing a possible mechanism by which modulation of a metabolic pathway might influence stem cell fate. Demethylation of histones and DNA can also be controlled by metabolic intermediates. Mutated forms of isocitrate dehydrogenase 1 (IDH1) and IDH2 that drive acute myeloid leukemia (AML) and other cancers, produce an oncometabolite (2-hydrogyglutarate) that can compete with the a-ketoglutarate requirement for enzymes involved in hydroxy-methylation and subsequent demethylation of DNA and histones. Recent studies indicate that 2-hydroxyglutarate plays a role in blocking differentiation of cancer cells. These and other observations linking intermediates in metabolism to stem cell maintenance will be discussed. Disclosures Cantley: Agios Pharmaceuticals: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.

Designing and Engineering Stem Cell Niches

MRS Bulletin ◽  
2010 ◽  
Vol 35 (8) ◽  
pp. 591-596 ◽  
Author(s):  
Ana I. Teixeira ◽  
Ola Hermanson ◽  
Carsten Werner
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Biology ◽  
Chemical Engineering ◽  
Polyglycolic Acid ◽  
Differentiated Cells ◽  
Extracellular Matrix Components ◽  
Stem Cell Niches

AbstractStem cells have received a lot of attention due to great promises in medical treatment, for example, by replacing lost and sick cells and re-constituting cell populations. There are several classes of stem cells, including embryonic, fetal, and adult tissue specific. More recently, the generation of so-called induced pluripotent stem (iPS) cells from differentiated cells has been established. Common criteria for all types of stem cells include their ability to self-renew and to retain their ability to differentiate in response to specific cues. These characteristics, as well as the instructive steering of the cells into differentiation, are largely dependent on the microenvironment surrounding the cells. Such “stem cell friendly” microenvironments, provided by structural and biochemical components, are often referred to as niches. Biomaterials offer attractive solutions to engineer functional stem cell niches and to steer stem cell state and fatein vitroas well asin vivo. Among materials used so far, promising results have been achieved with low-toxicity and biodegradable polymers, such as polyglycolic acid and related materials, as well as other polymers used as structural “scaffolds” for engineering of extracellular matrix components. To improve the efficiency of stem cell control and the design of the biomaterials, interfaces among stem cell research, developmental biology, regenerative medicine, chemical engineering, and materials research are rapidly developing. Here we provide an introduction to stem cell biology and principles of niche engineering and give an overview of recent advancements in stem cell niche engineering from two stem cell systems—blood and brain.

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