Archive for the ‘Somatic Stem Cells’ Category

Direct generation of human naive induced pluripotent stem …

Somatic Stem Cells | Posted by admin
Jun 05 2019

Evans, M. J. & Kaufman, M. H. Establishment in culture of pluripotential cells from mouse embryos. Nature 292, 154156 (1981).

Thomson, J. A. et al. Embryonic stem cell lines derived from human blastocysts. Science 282, 11451147 (1998).

Takahashi, K. et al. Induction of pluripotent stem cells from adult human fibroblasts by defined factors. Cell 131, 861872 (2007).

Hackett, J. A. & Surani, M. A. Regulatory principles of pluripotency: from the ground state up. Cell Stem Cell 15, 416430 (2014).

Davidson, K. C., Mason, E. A. & Pera, M. F. The pluripotent state in mouse and human. Development 142, 30903099 (2015).

Osafune, K. et al. Marked differences in differentiation propensity among human embryonic stem cell lines. Nat. Biotechnol. 26, 313315 (2008).

Weinberger, L., Ayyash, M., Novershtern, N. & Hanna, J. H. Dynamic stem cell states: naive to primed pluripotency in rodents and humans. Nat. Rev. Mol. Cell Biol. 17, 155169 (2016).

Luni, C. et al. High-efficiency cellular reprogramming with microfluidics. Nat. Methods 13, 446452 (2016).

Zhang, J. et al. LIN28 regulates stem cell metabolism and conversion to primed pluripotency. Cell Stem Cell 19, 6680 (2016).

Takashima, Y. et al. Resetting transcription factor control circuitry toward ground-state pluripotency in. Hum. Cell 158, 12541269 (2014).

Theunissen, T. W. et al. Systematic identification of culture conditions for induction and maintenance of naive human pluripotency. Cell Stem Cell 15, 471487 (2014).

Warren, L. et al. Highly efficient reprogramming to pluripotency and directed differentiation of human cells with synthetic modified mRNA. Cell Stem Cell 7, 618630 (2010).

Gafni, O. et al. Derivation of novel human ground state naive pluripotent stem cells. Nature 504, 282286 (2013).

Pastor, W. A. et al. Naive human pluripotent cells feature a methylation landscape devoid of blastocyst or germline memory. Cell Stem Cell 18, 323329 (2016).

Yoshida, Y., Takahashi, K., Okita, K., Ichisaka, T. & Yamanaka, S. Hypoxia enhances the generation of induced pluripotent stem cells. Cell Stem Cell 5, 237241 (2009).

Watanabe, K. et al. A ROCK inhibitor permits survival of dissociated human embryonic stem cells. Nat Biotechnol. 6, 681686 (2007).

Theunissen, T. W. et al. Molecular criteria for defining the naive human pluripotent state. Cell Stem Cell 19, 502515 (2016).

Guo, G. et al. Naive pluripotent stem cells derived directly from isolated cells of the human inner cell mass. Stem Cell Rep. 6, 437446 (2016).

Liu, X. et al. Comprehensive characterization of distinct states of human naive pluripotency generated by reprogramming. Nat. Methods 14, 10551062 (2017).

Kilens, S. et al. Parallel derivation of isogenic human primed and naive induced pluripotent stem cells. Nat. Commun. 9, 360 (2018).

Cacchiarelli, D. et al. Integrative analyses of human reprogramming reveal dynamic nature of induced pluripotency. Cell 162, 412424 (2015).

Smith, Z. D. et al. DNA methylation dynamics of the human preimplantation embryo. Nature 511, 611 (2014).

Okae, H. et al. Genome-wide analysis of DNA methylation dynamics during early human development. PLoS Genet. 10, e1004868 (2014).

Sahakyan, A. et al. Human naive pluripotent stem cells model X chromosome dampening and X inactivation. Cell Stem Cell 20, 87101 (2017).

Carbognin, E., Betto, R. M., Soriano, M. E., Smith, A. G. & Martello, G. Stat3 promotes mitochondrial transcription and oxidative respiration during maintenance and induction of naive pluripotency. EMBO J. 35, 618634 (2016).

Lee, J.-H. et al. Lineage-specific differentiation is influenced by state of human pluripotency. Cell Rep. 19, 2035 (2017).

Warrier, S. et al. Direct comparison of distinct naive pluripotent states in human embryonic stem cells. Nat. Commun. 8, 15055 (2017).

Hay, D. C. et al. Efficient differentiation of hepatocytes from human embryonic stem cells exhibiting markers recapitulating liver development in vivo. Stem Cells 26, 894902 (2008).

Errichelli, L. et al. FUS affects circular RNA expression in murine embryonic stem cell-derived motor neurons. Nat. Commun. 8, 14741 (2017).

Schlaeger, T. M. et al. A comparison of non-integrating reprogramming methods. Nat. Biotechnol. 33, 5863 (2014).

Nakagawa, M. et al. Generation of induced pluripotent stem cells without Myc from mouse and human fibroblasts. Nat. Biotechnol. 26, 101106 (2007).

Wang, Y. et al. Unique molecular events during reprogramming of human somatic cells to induced pluripotent stem cells (iPSCs) at nave state. eLife 7, e29518 (2018).

Urbach, A., Bar-Nur, O., Daley, G. Q. & Benvenisty, N. Differential modeling of fragile X syndrome by human embryonic stem cells and induced pluripotent stem cells. Cell Stem Cell 6, 407411 (2010).

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Quintanilla, R. H. Jr, Asprer, J. S. T., Vaz, C., Tanavde, V. & Lakshmipathy, U. CD44 is a negative cell surface marker for pluripotent stem cell identification during human fibroblast reprogramming. PLoS ONE 9, e85419 (2014).

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Somatic Stem Cells and Cancer – Stem Cell Centers …

Somatic Stem Cells | Posted by admin
May 04 2019

Can some somatic stem cells in our bodies be the source of common cancers? The Department of Health weighs in: So-called cancer stem cells are cancer cells that have stem cell-like properties, i.e., they can self-renew and differentiate into other cell types. They are associated with some, but not all, types of cancers.

Data suggest that recurrence of some cancers is caused by a failure of current therapies to target and kill these cancer stem cells. However, the relationship between cancer stem cells and somatic stem cells is unclear.

Somatic stem cells can become cancerous, but cancer stem cells do not necessarily come from somatic stem cells.

The similarities between somatic stem cells and cancer cells is so close (including the fundamental abilities to self-renew and differentiate) have led many to believe that cancers are caused by transforming mutations that happen in tissue-specific stem cells. One of the reasons this theory has been given some attention is because among all cancer cells within a particular tumor, only a very small cell fraction has the limited potential to regenerate the entire tumor cell population. Thus, these cells with stem-like properties have been termed cancer stem cells. Cancer stem cells can begin from mutation in normal somatic stem cells that stop controlling their physiological programs.

The stem cell theory of cancer proposes that among all cancerous cells, a few act as stem cells that reproduce themselves and sustain the cancer, much like normal stem cells normally renew and sustain our organs and tissues. In this view, cancer cells that are not stem cells can cause problems, but they cannot sustain an attack on our bodies over the long term, Stanford Medical said.

Over the years, there have been many theories about the origins of cancer. Truth be told, we still dont have all the answers on why some cancers come to be. However, one theory that is largely accepted postulates that: the growth of tissues and the reproduction of cells in our bodies are carefully regulated through the action of key sets of DNA instructions. When those DNA sequences are disruptedwhether through viruses, environmental causes like radiation or toxins, mutations transcription errors or inborn genetic flawscell reproduction becomes less well regulated. Eventually, those changes can produce the rapidly reproducing, self-protective and opportunistic cells that typify cancer, Stanford Medicine writes.

According to the American Cancer Society, men have a 39.66 percent chance, or one in three risk, of developing cancer over a lifetime. For women, the odds are slightly lower, at 37.65 percent.

The National Institute of Health states, Data from 2007 suggest that approximately 1.4 million men and women in the U.S. population are likely to be diagnosed with cancer and approximately 566,000 American adults are likely to die from cancer in 2008.

Stem cell transplants are commonly used today to help patients that have had blood-forming stem cells depleted after high doses of chemotherapy and/or radiation. Blood forming stem cells are a vital part of health because they grow and become varying types of blood cells that your body needs such as:

For your body to be healthy, all three blood cell types play a role.

Ideal candidates for stem cell therapy include those that are suffering from pain or dysfunction due to injury or age-related joint issues. If you are you worried that surgery, a lifelong dependency on pain medications, or a departure from your prior functionality are your only options, stem cell therapy may be for you.

Find out if you are a candidate for this revolutionary treatment by scheduling a free consultation with a stem cell therapist near you! If you have questions, or would like to know more about regenerative stem cell therapy, please call us at (877) 808-0016 or click contact us.

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Somatic Stem Cells and Cancer - Stem Cell Centers ...

Difference Between Embryonic and Somatic Stem Cells …

Somatic Stem Cells | Posted by admin
May 03 2019

The key difference between embryonic and somatic stem cells is that the embryonic stem cells are pluripotent undifferentiated cells that have embryonic origin while somatic stem cells are multipotent undifferentiated cells that are of tissue and organ origin.

Stem cells are undifferentiated cells which are capable of growing into true tissues or organs. Generally, there are two major stem cell types as embryonic stem cells and adult stem cells (somatic stem cells). In the case of differentiation, embryonic stem cells can differentiate into any type of cells. In contrast, somatic stem cells can only differentiate into several tissue-specific cells. Therefore, embryonic stem cells are pluripotent while somatic stem cells are multipotent. In simple words, the ability of differentiation is high in embryonic stem cells in comparison to that of somatic stem cells.

1. Overview and Key Difference 2. What areEmbryonic Stem Cells 3. What are Somatic Stem Cells 4. Similarities BetweenEmbryonic and Somatic Stem Cells 5. Side by Side Comparison Embryonic vs Somatic Stem Cells in Tabular Form 6. Summary

Embryonic stem cells are a type of undifferentiated cells present in early stages of embryonic development. The inner cell mass of the blastocyst is made up of embryonic stem cells. These embryonic stem cells are pluripotent in nature. Thus, they can differentiate into any type of cells. The extraction of embryonic stem cells can be done from the blastocyst stage of the embryonic development for stem cell culture. Following the extraction, the cells undergo maturation and division under in vitro conditions. The embryonic stem cells are able to grow in special high nutrient media where they differentiate into the three germ layers: ectoderm, endoderm, and mesoderm.

Figure 01: Embryonic Stem Cells

In modern therapy, embryonic stem cells are valuable tools in regenerative therapy and tissue replacement following injury or disease. The diseases that use embryonic stem cell therapy at present are diabetes, neurodegenerative disorders, spinal cord, and muscular injuries.

Somatic stem cells are the stem cells present in specific tissues and organs in adults. Therefore, adult stem cells is a synonym of somatic stem cells. Thus, adult stem cells originate from mature tissues and organs. They are multipotent cells; this means they can differentiate into several types of cells, but not pluripotent like embryonic stem cells. There are different types of somatic stem cells such as hematopoietic stem cells, intestinal stem cells, endothelial stem cells, neuronal stem cells, and mesenchymal stem cells.

Figure 02: Somatic Stem Cells

During division, somatic stem cells undergo two pathways. They are symmetric division and asymmetric division. The symmetric division produces daughter cells of similar properties whereas asymmetric division produces one similar daughter cell and a different progenitor cell.

There are many uses of somatic stem cells in research. They are useful in many drug testing protocols to check the effects of particular drugs or metabolites. Moreover, somatic stem cells are useful to determine the cellular behavior of particular organs and their signaling pathways. Furthermore, scientists use somatic cells as therapy as they are able to regenerate cells when proper conditions are present.

The key difference between embryonic and somatic stem cells is their site of extraction. Blastocyst stage of the embryonic development is the site of extraction of embryonic stem cells while specific tissues are the sites of extraction of somatic stem cell. Especially, embryonic stem cells can differentiate into any type of cells. In contrast, somatic stem cells cannot differentiate into all types of cells and can only differentiate into specific types of cells based on their origin. Therefore, this is also a major difference between embryonic and somatic stem cells.

Another difference between embryonic and somatic stem cells is their cell culturing process. Cell culturing of somatic stem cells are more laborious in comparison to embryonic stem cell culture.

The below infographic presents more information on the difference between embryonic and somatic stem cells.

Stem cells are undifferentiated cells. There are two broad classes of stem cells as embryonic stem cells and somatic stem cells. In summarizing the difference between embryonic and somatic stem cells, the embryonic stem cells can differentiate into any type of cells; thus, they are pluripotent. In contrast, somatic stem cells or adult stem cells can differentiate only into specific types of cells; thus, they are multipotent. Above all, the key difference between embryonic and somatic stem cells is the site of the derivation of these cell types. Embryonic stem cells are derived from the blastocyst while somatic stem cells are derived from specific organs upon the requirement.

1. Henningson, Carl T, et al. 28. Embryonic and Adult Stem Cell Therapy.The Journal of Allergy and Clinical Immunology, U.S. National Library of Medicine, Feb. 2003, http://www.ncbi.nlm.nih.gov/pubmed/12592319.

1. Human embryonic stem cells only A : Human_embryonic_stem_cells.png: (Images: Nissim Benvenisty)derivative work: Vojtech.dostal (talk) Human_embryonic_stem_cells.png (CC BY 2.5) via Commons Wikimedia 2. Sources of new adult -cells By Murtaugh, L.C. and Kopinke, D., Pancreatic stem cells (July 11, 2008), StemBook, ed. The Stem Cell Research Community, StemBook, doi/10.3824/stembook.1.3.1, http://www.stembook.org. (CC BY 3.0) via Commons Wikimedia

Samanthi holds a B.Sc. Degree in Plant Science, M.Sc. in Molecular and Applied Microbiology, and PhD in Applied Microbiology (progressing). Her research interests include Bio-fertilizers, Plant Microbe Interactions, Molecular Microbiology, Soil Fungi, and Fungal Ecology.

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Difference Between Embryonic and Somatic Stem Cells ...

Mosaic (genetics) – Wikipedia

Somatic Stem Cells | Posted by admin
Mar 08 2019

In genetics, a mosaic, or mosaicism, involves the presence of two or more populations of cells with different genotypes in one individual who has developed from a single fertilized egg.[1][2] Mosaicism has been reported to be present in as high as 70% of cleavage stage embryos and 90% of blastocyst-stage embryos derived from in vitro fertilization.[3]

Genetic mosaicism can result from many different mechanisms including chromosome non-disjunction, anaphase lag, and endoreplication.[3] Anaphase lagging is the most common way by which mosaicism arises in the preimplantation embryo.[3] Mosaicism can also result from a mutation in one cell during development in which the mutation is passed on to only its daughter cells. Therefore, the mutation is only going to be present in a fraction of the adult cells.[2]

Genetic mosaics may often be confused with chimerism, in which two or more genotypes arise in one individual similarly to mosaicism. However, in chimerism the two genotypes arise from the fusion of more than one fertilized zygote in the early stages of embryonic development, rather than from a mutation or chromosome loss.

Different types of mosaicism exist, such as gonadal mosaicism (restricted to the gametes) or somatic mosaicism.

Somatic mosaicism occurs when the somatic cells of the body are of more than one genotype. In the more common mosaics, different genotypes arise from a single fertilized egg cell, due to mitotic errors at first or later cleavages.

In rare cases, intersex conditions can be caused by mosaicism where some cells in the body have XX and others XY chromosomes (46, XX/XY).[4][5] In the fruit fly Drosophila melanogaster, where a fly possessing two X chromosomes is a female and a fly possessing a single X chromosome is a sterile male, a loss of an X chromosome early in embryonic development can result in sexual mosaics, or gynandropmorphs.[6][7] Likewise, a loss of the Y chromosome can result in XY/X mosaic males.[8]

The most common form of mosaicism found through prenatal diagnosis involves trisomies. Although most forms of trisomy are due to problems in meiosis and affect all cells of the organism, there are cases where the trisomy occurs in only a selection of the cells. This may be caused by a nondisjunction event in an early mitosis, resulting in a loss of a chromosome from some trisomic cells.[9] Generally this leads to a milder phenotype than in non-mosaic patients with the same disorder.

An example of this is one of the milder forms of Klinefelter syndrome, called 46/47 XY/XXY mosaic wherein some of the patient's cells contain XY chromosomes, and some contain XXY chromosomes. The 46/47 annotation indicates that the XY cells have the normal number of 46 total chromosomes, and the XXY cells have a total of 47 chromosomes.

Around 30% of Turner's syndrome cases demonstrate mosaicism, while complete monosomy (45, X) occurs in about 5060% of cases.

But mosaicism need not necessarily be deleterious. Revertant somatic mosaicism is a rare recombination event in which there is a spontaneous correction of a mutant, pathogenic allele.[10] In revertant mosaicism, the healthy tissue formed by mitotic recombination can outcompete the original, surrounding mutant cells in tissues like blood and epithelia that regenerate often.[10] In the skin disorder ichthyosis with confetti, normal skin spots appear early in life and increase in number and size over time.[10]

Other endogenous factors can also lead to mosaicism including mobile elements, DNA polymerase slippage, and unbalanced chromosomal segregation.[11] Exogenous factors include nicotine and UV radiation.[11] Somatic mosaics have been created in Drosophila using Xray treatment and the use of irradiation to induce somatic mutation has been a useful technique in the study of genetics.[12]

True mosaicism should not be mistaken for the phenomenon of Xinactivation, where all cells in an organism have the same genotype, but a different copy of the X chromosome is expressed in different cells. The latter is the case in normal (XX) female mammals, although it is not always visible from the phenotype (like it is in calico cats). However, all multicellular organisms are likely to be somatic mosaics to some extent.[13]

Somatic mutation leading to mosaicism is prevalent in the beginning and end stages of human life.[11] Somatic mosaics are common in embryogenesis due to retrotransposition of L1 and Alu transposable elements.[11] In early development, DNA from undifferentiated cell types may be more susceptible to mobile element invasion due to long, un-methylated regions in the genome.[11] Further, the accumulation of DNA copy errors and damage over a lifetime lead to greater occurrences of mosaic tissues in aging humans. As our longevity has increased dramatically over the last century, our genome may not have had time to adapt to cumulative effects of mutagenesis.[11] Thus, cancer research has shown that somatic mutations are increasingly present throughout a lifetime and are responsible for most leukemia, lymphomas, and solid tumors.[14]

Genomic mosaiscism arises in developing and in adult brain cells leading to diverse, seemingly random, genomic changes.[15] A frequent type of neuronal genomic mosaicism is copy number variation. Possible sources of such variation were suggested to be incorrect repair of DNA damages and somatic recombination.[15][16]

One basic mechanism which can produce mosaic tissue is mitotic recombination or somatic crossover. It was first discovered by Curt Stern in Drosophila in 1936. The amount of tissue which is mosaic depends on where in the tree of cell division the exchange takes place. A phenotypic character called "Twin Spot" seen in Drosophila is a result of mitotic recombination. However, it also depends on the allelic status of the genes undergoing recombination. Twin spot occurs only if the heterozygous genes are linked in repulsion i.e. trans phase. The recombination needs to occur between the centromere the adjacent gene. This gives an appearance of yellow patches on the wild type background in Drosophila. another example of mitotic recombination is the Bloom's syndrome which happens due to the mutation in the blm gene. The resulting BLM protein is defective. the defect in RecQ an helicase facilitates the defective unwinding of DNA during replication and is thus associated with the occurrence of this disease.[17][18]

Germline or gonadal mosaicism is a special form of mosaicism, where some gametesi.e., sperm or oocytescarry a mutation, but the rest are normal.[19][20]

The cause is usually a mutation that occurred in an early stem cell that gave rise to all or part of the gametes.

This can cause only some offspring to be affected, even for a dominant disease.

Genetic mosaics can be extraordinarily useful in the study of biological systems, and can be created intentionally in many model organisms in a variety of ways. They often allow for the study of genes that are important for very early events in development, making it otherwise difficult to obtain adult organisms in which later effects would be apparent. Furthermore, they can be used to determine the tissue or cell type in which a given gene is required and to determine whether a gene is cell autonomous. That is, whether or not the gene acts solely within the cell of that genotype, or if it affects the entire organism of neighboring cells which do not themselves contain that genotype.

The earliest examples of this involved transplantation experiments (technically creating chimeras) where cells from a blastula stage embryo from one genetic background are aspirated out and injected into a blastula stage embryo of a different genetic background.

Genetic mosaics are a particularly powerful tool when used in the commonly studied fruit fly, where specially-selected strains frequently lose an X[7] or a Y[8] chromosome in one of the first embryonic cell divisions. These mosaics can then be used to analyze such things as courtship behavior,[7] female sexual attraction,[21] and the autonomy or non-autonomy of particular genes.

Genetic mosaics can also be created through mitotic recombination. Such mosaics were originally created by irradiating flies heterozygous for a particular allele with X-rays, inducing double-strand DNA breaks which, when repaired, could result in a cell homozygous for one of the two alleles. After further rounds of replication, this cell would result in a patch, or "clone" of cells mutant for the allele being studied.

More recently the use of a transgene incorporated into the Drosophila genome has made the system far more flexible. The flip recombinase (or FLP) is a gene from the commonly studied yeast Saccharomyces cerevisiae which recognizes "flip recombinase target" (FRT) sites, which are short sequences of DNA, and induces recombination between them. FRT sites have been inserted transgenically near the centromere of each chromosome arm of Drosophila melanogaster. The FLP gene can then be induced selectively, commonly using either the heat shock promoter or the GAL4/UAS system. The resulting clones can be identified either negatively or positively.

In negatively marked clones the fly is transheterozygous for a gene encoding a visible marker (commonly the green fluorescent protein or GFP) and an allele of a gene to be studied (both on chromosomes bearing FRT sites). After induction of FLP expression, cells that undergo recombination will have progeny that are homozygous for either the marker or the allele being studied. Therefore, the cells that do not carry the marker (which are dark) can be identified as carrying a mutation.

It is sometimes inconvenient to use negatively marked clones, especially when generating very small patches of cells, where it is more difficult to see a dark spot on a bright background than a bright spot on a dark background. It is possible to create positively marked clones using the so-called MARCM ("mosaic analysis with a repressible cell marker", pronounced [mark-em]) system, developed by Liqun Luo, a professor at Stanford University, and his post-doc Tzumin Lee who now leads a group at Janelia Farm Research Campus. This system builds on the GAL4/UAS system, which is used to express GFP in specific cells. However a globally expressed GAL80 gene is used to repress the action of GAL4, preventing the expression of GFP. Instead of using GFP to mark the wild-type chromosome as above, GAL80 serves this purpose, so that when it is removed by mitotic recombination, GAL4 is allowed to function, and GFP turns on. This results in the cells of interest being marked brightly in a dark background.[22]

In 1929, Alfred Sturtevant studied mosaicism in Drosophila.[6] A few years later, In the 1930s, Curt Stern demonstrated that genetic recombination, normal in meiosis, can also take place in mitosis.[23][24] When it does, it results in somatic (body) mosaics. These are organisms which contain two or more genetically distinct types of tissue.[25] The term "somatic mosaicism" was used by C.W. Cotterman in 1956 in his seminal paper on antigenic variation.[11]

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Mosaic (genetics) - Wikipedia

What is the Difference Between Embryonic and Somatic Stem Cells

Somatic Stem Cells | Posted by admin
Feb 27 2019

Themain differencebetween embryonic and somatic stem cells is that the embryonic stem cells are pluripotent whereas the somatic stem cells are multipotent.That means; the embryonic stem cells can become all types of cells in the body while somatic stem cells can differentiate into several types of cells, but not all.

Embryonic and somatic stem cells are two types of stem cells that occur during the lifetime of animals. Furthermore, embryonic stem cells occur in the inner cell mass of the embryo while somatic stem cells occur in most of the organs of the body including bone marrow, skin, skeletal muscles, liver, etc.

1. What are Embryonic Stem Cells Definition, Potency, Differentiation 2. What are Somatic Stem Cells Definition, Potency, Differentiation 3. What are the Similarities Between Embryonic and Somatic Stem Cells Outline of Common Features 4. What is the Difference Between Embryonic and Somatic Stem Cells Comparison of Key Differences

Embryonic Stem Cells, Multipotent, Pluripotent, Somatic Stem Cells, Three Germ Layers

Embryonic stem cells are the cells in the early stages of the embryo. The zygote, which is the conceptus of fertilization, divides by mitosis, forming the morula. After 5-6 days of fertilization, the morula develops into the blastocyst that contains two parts; thetrophoblastand the inner cell mass. Thetrophoblastis the outer layer of the embryo, which contains cells that develop into the placenta and umbilical cord. Here, the cells in the inner cell mass are pluripotent and are capable of differentiating into any type of cells in the body.

Figure 1: Stem Cell Differentiation

Moreover, they differentiate into the cells in the three germ layers; ectoderm, endoderm, and mesoderm. The cells in the three germ layers are multipotent stem cells that can differentiate into a particular group of cells in our body. Therefore, the cells in the ectoderm differentiate into the epidermis, lens of the eye, sebaceous glands, hair, nails, toothenamel, etc. In addition, the cells in mesoderm differentiate into muscle, bones, connective tissue, cartilage, adipose tissue, circulatory and the lymphatic system, dermis,notochord, etc. Furthermore, the cells in the endoderm differentiate into the stomach, colon, liver, bladder, pancreas, lungs, etc.

Somatic stem cells are the adult stem cells that occur inside the specialized tissues including bone marrow, skin, skeletal muscles, brain, liver, pancreas, dental pulp, etc. Furthermore, these cells are multipotent and can only differentiate into the several types of functionally-related cells that belong to the tissue of origin of the stem cells. Therefore, they continuously divide to produce new cells. A part of these new cellsdifferentiatesinto the functionally-specialized cells in that tissue and the rest of the cells renew the existing stem cell population.

Figure 2: Stem Cell Uses

For example, dividing hematopoietic stem cells in the bone marrow differentiate into the cells in the blood including red blood cells, white blood cells, and platelets. In addition, the stem cells in the bone marrow are the most studied type of somatic stem cells in the human body. However, somatic stem cells are difficult to identify, purify, and grow in cultures. Therefore, these stem cells are rarely subjected to the studies.

Embryonic stem cells refer to the stem cells derived from the undifferentiated inner mass cells of a human embryo while somatic stem cells refer to the undifferentiated cells found throughout the body that divide to replenish dying cells and regenerate damaged tissues. This is the basic difference between embryonic and somatic stem cells.

Embryonic stem cells occur in the three germ layers of the embryo while somatic stem cells occur in most of the body organs including skeletal muscles, bone marrow, skin, liver, etc.

Potency isthe main difference between embryonic and somatic stem cells. Embryonic stem cells are multipotent. That is; they can differentiate into any cell type in the body. In contrast, somatic stem cells are pluripotent. That is; they can differentiate only into several types of cells in the body, but not all types.

Embryonic stem cell studies are less known while somatic stem cell studies are well known. This is another difference between embryonic and somatic stem cells.

Embryonic stem cells are the stem cells in the inner cell mass of the embryo. Moreover, these cells are multipotent and they can differentiate into any type of cells in the body. On the other hand, somatic stem cells are the stem cells in the adult body organs. These cells can only differentiate into several types of cells in that organ, helping to replenish the damaged or aged cells. Therefore, the main difference between embryonic and somatic stem cells is the potency.

1.Stem Cell Basics V.National Institutes of Health, U.S. Department of Health and Human Services,Available Here

1. 422 Feature Stem Cell new By OpenStax College Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia 2. Stem cell treatments By Hggstrm, Mikael (2014). Medical gallery of Mikael Hggstrm 2014. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.008. ISSN 2002-4436 (Public Domain) via Commons Wikimedia

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What is the Difference Between Embryonic and Somatic Stem Cells

Somatic Cells – Definition and Examples | Biology Dictionary

Somatic Stem Cells | Posted by admin
Nov 14 2018

Somatic Cells Definition

Somatic cells are any cell in the body that are not gametes (sperm or egg), germ cells (cells that go on to become gametes), or stem cells. Essentially, all cells that make up an organisms body and are not used to directly form a new organism during reproduction are somatic cells. The word somatic comes from the Greek word (soma), which means body. In the human body, there are about 220 types of somatic cells.

There are many different kinds of somatic cells in the human body because nearly every cell found inside and on the surface of the human body, with the exception of cells that become sperm and eggs, is a somatic cell. In addition, mammals have many organ systems that specialize in specific functions, so there are many different specialized cells. The following is an overview of a few main types of cells in the human body.

Old bone cells are constantly being replaced with new bone cells. The two broad categories of bone cells are called osteoblasts and osteoclasts. Osteoblasts form bone and help maintain it. They are cuboidal, or square-shaped, and they make proteins that form bone. They also communicate with each other and produce certain molecules such as growth factors, which promote bone growth. Osteoclasts, on the other hand, resorb, or dissolve, old bone. They are large cells that have multiple nuclei. When the work of an osteoblast or osteoclast is done, it undergoes a programmed cell death known as apoptosis.

Muscle cells are also known as myocytes. They are long, tube-shaped cells. There are three types of muscle which are each made up of specialized myocytes: smooth muscle, cardiac muscle, and skeletal muscle. Smooth muscle lines the walls of internal organs such as the bladder, uterus, and digestive tract. Cardiac muscle is only found in the heart, and it allows the heart to pump blood. Skeletal muscle is attached to bone and helps move the body.

The various parts of myocytes have special terminology because myocytes are so different from other types of cells. The cell membrane is called the sarcolemma, the mitochondria are called sarcosomes, and the cytoplasm is called the sarcoplasm. The sarcomere is the part of the cell that contracts and allows muscle movement, and they form long chains called myofibrils that run throughout each muscle fiber. Muscle cells cannot divide to form new cells. This means that even though muscles can get bigger through exercise, babies actually have more myocytes than adults.

Nerve cells are called neurons. Neurons are found throughout the body, but there is an especially high density in the brain and spinal cord, which control the bodys movements. Neurons send and receive information to and from other neurons and organs via chemical and electrical signaling. Neurons maintain a certain voltage, and when this voltage changes, it creates an electrochemical signal called an action potential. When an action potential occurs in a neuron, the neuron will release neurotransmitters, which are chemicals that affect target cells. Some examples of neurotransmitters are dopamine, serotonin, epinephrine (adrenaline), and histamine.

Neurons have a unique structure as shown in the diagram above. The main parts of a neuron are the soma, axon, and dendrites. The soma is the body of the cell and contains the nucleus. The axon is a long protrusion that transmits electrical impulses. The dendrites fan out from the soma and receive impulses from other neurons. The end of the axon branches out into axon terminals, which is where neurotransmitters are released.

Blood cells are called hematopoietic cells or hemocytes. There are three general types of blood cells: red blood cells, known as erythrocytes, white blood cells, or leukocytes, and platelets, also known as thrombocytes or yellow blood cells. These cells, along with plasma, comprise the contents of blood.

Erythrocytes carry oxygen to cells via the molecule hemoglobin, and they collect the waste product carbon dioxide from cells. They make up 40 to 45 percent of the bloods volume. Approximately one-fourth of the cells in the human body are erythrocytes. They live for around 100 to 120 days, and they do not have a nucleus when mature. Leukocytes defend the body against foreign substances and infectious disease agents like viruses and bacteria. They have a very short lifespan of only three to four days. Platelets are small cell fragments that help blood to clot after an injury. They also have a short lifespan, living for five to nine days.

Somatic cells are produced through the cell division process of mitosis. They contain two copies of each chromosome, one from an organisms mother and one from their father. Cells with two copies of each chromosome are called diploid. Sperm and egg cells, called gametes, are formed through meiosis, which is a slightly different cell division process that results in the cells having only one copy of each chromosome. These cells are called haploid. Gametes are haploid because a sperm and an egg fuse during fertilization to create a new organism with diploid cells. Mutations in somatic cells can affect an individual organism, but they do not affect the offspring since they are not passed on during reproduction. However, mutations that occur in gametes can affect offspring since the gametes are passed down. When gametes fuse, they become the offsprings first somatic cell, which subsequently divides to form all of their other somatic cells. Therefore, while mutations in somatic cells will not affect the next generation, mutations in gamete cells do and can sometimes have drastic effects. For example, if a large-scale mutation occurs and there is an extra chromosome in the fertilized egg, all the somatic cells will also have that extra chromosome when it divides. An extra chromosome 21 results in Down Syndrome.

1. Which type of cell is NOT a somatic cell? A. Leukocyte B. Myocyte C. Osteoblast D. Gamete

Answer to Question #1

D is correct. Gametes such as sperm and eggs are not somatic cells. They are germline cells, which are cells that pass on genetic material through the process of reproduction. Leukocytes (white blood cells), myocytes (muscle cells) and osteoblasts (a type of bone cell) are all somatic cells.

2. What is the approximate lifespan of an erythrocyte? A. 3-4 days B. 5-9 days C. 100-120 days D. 365-395 days

Answer to Question #2

C is correct. Erythrocytes, or red blood cells, live about 100-120 days, which is the longest lifespan of a blood cell. Leukocytes live for 3-4 days, while platelets live for 5-9 days.

3. What is the function of an osteoclast? A. To form and help maintain bone B. To attach to bone and allow it to move C. To resorb old bone D. To release neurotransmitters

Answer to Question #3

C is correct. Osteoclasts are bone cells that resorb, or break down, old bone so that osteoblasts can then replace it with newly created bone. Choice A describes osteoblasts. Choice C is referring to muscle cells, and choice D describes neurons.

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Somatic Cells - Definition and Examples | Biology Dictionary

Stem Cell Quick Reference – Learn.Genetics

Somatic Stem Cells | Posted by admin
Sep 09 2018

Are you confused about all the different types of stem cells? Read on to learn where different types of stem cells come from, what their potential is for use in therapy, and why some types of stem cells are shrouded in controversy.

Researchers are working on new ways to use stem cells to cure diseases and heal injuries. Learn more about unlocking stem cell potential.

Somatic stem cells (also called adult stem cells) exist naturally in the body. They are important for growth, healing, and replacing cells that are lost through daily wear and tear.

Stem cells from the blood and bone marrow are routinely used as a treatment for blood-related diseases. However, under natural circumstances somatic stem cells can become only a subset of related cell types. Bone marrow stem cells, for example, differentiate primarily into blood cells. This partial differentiation can be an advantage when you want to produce blood cells; but it is a disadvantage if you're interested in producing an unrelated cell type.

Most types of somatic stem cells are present in low abundance and are difficult to isolate and grow in culture. Isolation of some types could cause considerable tissue or organ damage, as in the heart or brain. Somatic stem cells can be transplanted from donor to patient, but without drugs that suppress the immune system, a patient's immune system will recognize transplanted cells as foreign and attack them.

Therapy involving somatic stem cells is not controversial; however, it is subject to the same ethical considerations that apply to all medical procedures.

Embryonic stem (ES) cells are formed as a normal part of embryonic development. They can be isolated from an early embryo and grown in a dish.

ES cells have the potential to become any type of cell in the body, making them a promising source of cells for treating many diseases.

Without drugs that suppress the immune system, a patient's immune system will recognize transplanted cells as foreign and attack them.

When scientists isolate human embryonic stem (hES) cells in the lab, they destroy an embryo. The ethical and legal implications of this have made some reluctant to support research involving hES cells. In recent years, some researchers have focused their efforts on creating stem cells that don't require the destruction of embryos.

Learn more about the controversy behind embryonic stem cells and why new stem-cell technologies may bring it to an end. The Stem Cell Debate: Is It Over?

Induced pluripotent stem (iPS) cells are created artificially in the lab by "reprogramming" a patient's own cells. iPS cells can be made from readily available cells including fat, skin, and fibroblasts (cells that produce connective tissue).

Mouse iPS cells can become any cell in the body (or even a whole mouse). Although more analysis is needed, the same appears to be true for human iPS cells, making them a promising source of cells for treating many diseases. Importantly, since iPS cells can be made from a patient's own cells, there is no danger that their immune system will reject them.

iPS cells are much less expensive to create than ES cells generated through therapeutic cloning (another type of patient-specific stem cell; see below). However, because the "reprogramming" process introduces genetic modifications, the safety of using iPS cells in patients is uncertain.

Therapy involving iPS cells is subject to the same ethical considerations that apply to all medical procedures.

Therapeutic cloning is a method for creating patient-specific embryonic stem (ES) cells.

Therapeutic cloning can, in theory, generate ES cells with the potential to become any type of cell in the body. In addition, since these cells are made from a patient's own DNA, there is no danger of rejection by the immune system.

In 2013, for the first time, a group of researchers used therapeutic cloning to make ES cells. The donor nucleus came from a child with a rare genetic disorder. However, the cloning process remains time consuming, inefficient, and expensive.

Therapeutic cloning brings up considerable ethical considerations. It involves creating a clone of a human being and destroying the cloned embryo, and it requires a human egg donor.

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Stem Cell Quick Reference - Learn.Genetics

Where Do Stem Cells Come From? – verywellhealth.com

Somatic Stem Cells | Posted by admin
Jul 02 2018

Stem cells are specialized cells that have the potential to develop into not one but many different types of cell. They are unlike any other cell for three specific reasons:

Currently, blood stem cells are the only type regularly used for treatment. In cases of leukemia or lymphoma, this type of cell is used in a procedure we commonly refer to as a bone marrow transplant. For this purpose, only adult stems cells are used.

When it comes to stem cell research, the cells may come from any number of different sources, including adult donors, embryos, or genetically altered human cells.

The cells of the bone marrow produce all of your healthy blood cells, including red blood cells, white blood cells, and platelets. Hematopoietic stem cells are those found in bone marrow that serves as the "parent" for all of these different types of cells.

Hematopoietic stem cells are transplanted into a person with cancer to help replenish bone marrow. The procedure is often used when high dose chemotherapy effectively destroys the existing stem cells in a persons bone marrow.

To remedy this, donated stem cells are injected into a vein and eventually settle in the bone marrow where they start producing healthy, new blood cells.

Years ago, the only source for hematopoietic stem cells were those taken from bone marrow. It was soon after discovered that many of these cells were circulating freely in the bloodstream.

In time, scientists learned how to harvest these cells from circulating blood and to transplant them directly into a donor.

This type of transplant known as a peripheral blood stem cell transplant, or PBSCT has become the more common procedure, although both methods are still used. PBSCT is far less invasive and doesnt require the removal of marrow from the hip bone.

Adult stem cells, called somatic stem cells, are derived from a human donor. Hematopoietic stem cells are the most widely known example. Scientists have found somatic stem cells in more tissues than was once imagined, including the brain, skeletal muscle, skin, teeth, heart, gut, liver, ovarian cells, and testis.

Embryonic stem cells are controversial since they are derived from human embryos that have either been destroyed or harvested for science. Embryonic stem cells were first grown in a laboratory in 1998 for reproductive purposes. Today, they are used primarily for research into treatments or cures for cancers, blindness, juvenile diabetes, Parkinsons, spinal cord injuries, and genetic disorders of the immune system.

Embryonic stem cells are pluripotent, meaning they are able to grow into the three types of germ cell layers that make up the human body (ectoderm, mesoderm, endoderm).

In other words, they can develop into each of the more than 200 cell types if specified to do so.

Induced pluripotent stem cells, or iPSCs, are somatic stem cells that have been genetically reprogrammed to be more like embryonic stem cells. iPSCs usually start out as skin or blood cells which then undergo genetic programming.

iPSCs were first developed in 2006 and pose one major advantage over somatic and embryonic stem cells: they can be made in a patient-matched manner. What this means is that a lab can tailor-make a pluripotent stem cell line individualized from a persons own cells or tissues.

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Where Do Stem Cells Come From? - verywellhealth.com

What Is Another Name for Somatic Stem Cells and What Do …

Somatic Stem Cells | Posted by admin
Jun 22 2018

Somatic stem cells are also referred to as adult stem cells. Unlike embryonic stem cells, somatic stem cells come from a fully developed human being. Somatic stem cells are somewhat specialized to produce certain kinds of cells. However, scientists are currently working on ways to increase their range of use in cutting-edge therapies.

Adult stem cells have been found in a wide range of organs and tissues, including bone marrow, blood vessel, brain, epithelium, heart, intestine, liver, ovary, skeletal muscle, skin, teeth, and testis.

While these cells are programmed to become a certain type of cell, they are still capable of differentiation. For example, bone marrow stem cells can differentiate into either red or white blood cells. While brain stem cells could form neurons or supporting brain cells, they would typically not become cell types found in other organs.

Somatic stem cells typically divide to form mature cell types that have the characteristics necessary to become a functional part of tissues or organs, a process called normal differentiation.

Certain types of somatic stem cells have been found to have the capacity to give rise to cell types for organs or tissues not in their lineage. For example, brain stem cells that differentiate into cardiac muscle cells. This phenomenon is called transdifferentiation.

Doctors performed the first bone marrow transplant in 1968. The procedure also marked the first medical use of somatic stem cells, as bone marrow cells can differentiate into red blood cells or white blood cells. Today bone marrow transplants are used to treat a range of ailments, from blood cancers to immune disorders.

In 2010, a biotech company called Neuralstem began conducting clinical trials for the use of spinal cord stem cells to treat Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrigs Disease. The second phase of these trials was conducted in September 2013.

With embryonic stem cells, which are stem cells derived from fertilized human eggs, sparking an intense political and ethical debate, many researchers are turning to somatic stem cells as a less divisive alternative.

The problems is that embryonic stem cells can become any type of cell in the body -- while somatic cells are more restricted to a specific lineage. Embryonic stem cells are also more easily grown in culture, according to the National Institutes of Health.

However, because a patient's own cells can be used in a somatic stem cell treatment regimen -- they are thought to be less likely to cause a rejection after transplantation. The lack of a rejection response by the body's immune system would eliminate the need for immunosuppressive drugs, which often cause undesirable side effects.

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Difference Between Somatic Cells and Gametes …

Somatic Stem Cells | Posted by admin
Jun 19 2018

Somatic Cells vs Gametes

The most important structures in the cell during division are the chromosomes, which contain DNA. This is because they are responsible for the transmission of the hereditary information from one generation to the next. Cells in the body are of two types depending on the number of chromosomes present in the nucleus. The two types are somatic cells and gametes.

What are Somatic Cells?

A somatic cell is any cell other than a germline cell found in the body of a multicellular organism. These are diploid cells having two sets of chromosomes; one is maternal and the other is paternal. When considering one homologous pair, one chromosome is inherited from the mother, and the other is inherited from the father. For an example, a human somatic cell contains 46 chromosomes arranged in to 23 pairs in which one chromosome of each pair is maternal, and the other is paternal. Stem cells produced by mitosis undergo differentiation and give rise to different types of somatic cells, which intern form almost all the internal and external structures of the body.

What are Gametes?

Unlike the somatic cells, gametes are haploid cells, which carry unpaired chromosomes. A gamete of a particular multicellular organism always carries only half the number of chromosomes carried by a somatic cell of that particular organism. For an example, a human gamete contains only 23 chromosomes where as a human somatic cell contains 46 chromosomes. Germ cells are the cells which give rise to gametes. Meiosis takes place during gametogenesis (process of gamete production) giving rise to haploid cells. Haploid gametes fuse during sexual reproduction giving rise to a diploid zygote.

What is the Difference between Somatic Cells and Gametes?

Somatic cells are diploid cells, whereas the gametes are haploid cells.

Stem cells give rise to somatic cells, and germ cells give rise to gametes.

Meiosis does not take place during the production of somatic cells, whereas meiosis takes place during gametogenesis (production of gametes) giving rise to haploid cells.

Somatic cells contain homologous pairs of chromosomes, whereas gametes contain only unpaired chromosomes.

Somatic cells form internal and external structures of the body, whereas gametes do not.

Somatic cells are found almost everywhere in the body, whereas gametes are restricted to certain parts.

Somatic cells do not fuse during sexual reproduction, whereas gametes fuse during sexual reproduction giving rise to a diploid zygote.

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