Induced Pluripotent Stem Cells: Methods of Production, Characterization and Applications to Medicine
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Induced Pluripotent Stem Cells: Methods of Production, Characterization and Applications to Medicine
Introduction
By definition, induced pluripotent stem cells (iPSCs) are somatic cells with preprogrammed features (Kamath et al. 2017). In essence, they are often modified to mimic embryonic stem cells through the expression of ectopic factors linked to gene transcription. Today, the production and characterization of iPSCs is poised to be one of the most significant hallmarks in biological stem cell research. The iPSCs are known to differentiate into a variety of cell types via indefinite
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In this study, expression of the transcription factor reduced while that of the E-cadherin cell receptor was up-regulated. The events were commensurate with the mesenchymal-epithelial transition (MET) process, which is the converse of the epithelial-mesenchymal transition (EMT) phase of embryonic development. Reprogramming embodies the transient expression of OSKM transcription factors linked to pluripotency in somatic cells. These factors include c-Myc or Myc, KLF4, SOX2, and Octa4 (Li et al. 2017, p.6). They are critical to clinical translation of cell reprogramming in vivo. Their colonies resemble ESCs phenotypically, molecularly, and morphologically when compacted and placed on a culture dish. Initially, Chen et al. (2013, p.1316) hypothesized that the process of iPSC programming can be enhanced by small molecules that inhibit EMT. Indeed, this hypothesis was confirmed upon establishing that the speed and efficiency of iPSC programming in human cells can be enhanced by an MET promoter, SB431542, which targets the signaling pathway of the transforming growth factor-β. This study has pointed out the role of β-receptor signaling in the stabilization of E-cadherin and programming of iPSCs. A subsequent study by Li and Tariq (2012) also echoed the role of E-cadherin in the induction of pluripotent stem cells where luteolin and apigenin molecules were used to up-regulate its expression. Cell programming to iPSCs can also be improved by other small molecule
Pluripotent stem cells are the stem cells that can only differentiate into a limited range of differentiated cells. (2) They have the ability to give rise to all somatic cells from ectoderm, mesoderm and endoderm, as well as gametes. Naturally it can be found in embryos as Embryonic stem cells (ES cells). Induced pluripotent stem cells (iPS cells or iPSC) are the pluripotent stem cells that are generated directly from adult cells, first discovered by Shinya Yamanaka in 2006 by using a set of reprogramming factors (Oct4, Sox2, Klf4, and c-Myc or LIN28 and Nanog) (3) to reprogram mature cells back to a pluripotent state (4).
Others develop into muscle cells that can contract and also into nerve cells. Because they have the potential to become such a wide variety of specialized cells, embryonic stem cells are described as pluripotent. Plurip.0otency is one of two key features of embryonic stem cells. The second key feature of embryonic stem cells is their ability to divide or self renew for an indefinite period while retaining their undifferentiated, pluripotent state. As the cell mass grows, the population can be further expanded by growing in larger tissue culture flasks. An unlimited number of undifferentiated, pluripotent stem cells can be produced (Sumanas Inc. 2007).
The creation of induced pluripotent stem cells by direct reprogramming has allowed for the circumvention of using embryonic stem cells while still leaving the cells with the ability to maintain pluripotency. Instead of ES cells which were originally derived from the epiblast of mouse embryos, IPS cells were generated from mouse embryonic fibroblasts. This eliminated both any ethical concerns for whether those cells were a living being or not and the need to destroy embryos at the blastocyst stage. An advantage of IPS cells is that they are derived from human somatic cells which makes them easy to acquire due to the possibility of using skin or blood cells. They can also be grown and differentiated individually for each person that the sample of somatic cells is taken from which eliminates the possibility of having any immune reaction and rejection to the differentiated cells during transplantation. These characteristics of IPS cells are important because they are what enables us to safely and accurately transform these affected cells from patients cells into neurons and confidently study them.
This short description of the beach that Billy Prior and Sarah Lumb travel to for a date occurs late in part two of four in the novel “Regeneration” by Pat Barker. Third person point of view is used by the author to show the happiness of the beach and the true sadness felt by Billy Prior due to his experience in the First World War. The metaphor of comparing Billy Prior to a ghost effectively describes Prior’s state of being due to the current war. First of all, in the novel
Although embryonic stem cells contain abilities to enrich human health, a less controversial source of stem cells remains- adult stem cells. Collecting adult stem cells takes place in numerous locations of the body such as: bone marrow, muscle, the brain, umbilical cords, and adipose tissue (Guinan 308). Goldstein documents of experimental findings how human brain stem cells “can achieve ninety to ninety-five perfect purity in combination with several previous steps” (207). However, scientists remained uncertain about the functionality of adult stem cells because they “typically generate the cell types of the tissues in which they reside” (“Stem Cell Basics” 1), but in 2006 a Kyoto University team discovered the ability to engineer adult stem cells into pluripotent stem cells (“New Method” 4). Recent technology allows scientists to “directly covert somatic cells to pluripotent cells regardless of availability of embryonic cells” (Han 278). This technology may foster the growth of stem cell research because it removes the challenge of accessing to pluripotent cells. Induced pluripotent stem cells potential to “promote patient specific and disease specific drug development” (Manohar 1) makes them even more constructive than embryonic stem cells when considering rejection by the host. Induced pluripotent stem cells attain the same flexibility as embryonic
Embryonic stem cells (hESC) are pluripotent. They are obtained from the inner mass of a 5-6 day old human blastocyst that consists of approximately 100 cells (Bongso & Lee, 2005, p. 3).
Human embryonic stem cells (hESCs) are pluripotent and are obtained from the inner mass of a 4-5 day old human blastocyst that consists of approximately 100 cells (“Stem cell research,” 2009).
Embryonic stem cells are found in human blastocysts (Marcovitz 17). A blastocyst is a very young embryo (just a few days old) that contains around 200 undifferentiated stem cells (Marcovitz 17). German Zoologist Valentin Hacker coined the term “stem cell” after he discovered them in a blastocyst of a crustacean (Marcovitz 18). Embryonic stem cells were collected for the first time in 1988 by Dr. James Thomson of University of Wisconsin and by Dr. John Gearheart of Johns Hopkins (Panno 76). These stem cells are unspecialized; they do not perform a specific function like cells such as muscle and nerve do (“Stem Cells”). They are also pluripotent, meaning they have the ability to divide and become specialized cells (“Stem Cells”). This is why stem cells hold so
As technology advances, the use of embryonic stem cell research has also expanded. Stem cells have shown promise in personalized medicine as they are undifferentiated and easily conform with the surrounding cells. There are two areas of research that stem cells are showing massive potential, cell regeneration and organ transplantation. It is thought that stem cells have the capability to “model genetic disorders in a reliable fashion such that no other method allows. It seems likely that we could use stem cells to model cells with genetic disorders and figure out how to mute certain genes, thus eliminating or drastically reducing the effects of the disease,” (1). Although embryonic stem cells (ESC) are showing great potential towards medical advancements, there are many people who are opposed to the idea of using these cells due to the aggressive nature in which we extract ESC.
The 70's focused on research that involved fetuses in utero. The 80's shifted to research of transplantation of fetal tissue into adults with serious medical conditions such as diabetes, Parkinson's, and spinal cord injuries. The latest saga involves using cells from days-old "spare" embryos that are created in infertility treatment process and all are considered unethical and unmoral issues.
Researches are continuously looking for ways to cure and treat all kinds of diseases, so why are there limits being put on the kinds of treatments that can be used to treat or cure a disease? Embryonic Stem Cells can be used to treat many different diseases, but some people have their opinion that using these stem cells in medicine is unethical because they are coming from a human embryo. There are countries that have banned the use of embryonic stem cells in medicine, and in America there are people arguing that it should be banned here. But what about all of the lives these stem cells are saving, what if research continues and these embryonic stem cells end up being a cure to a disease? With this in mind, human embryonic stem cells
iPSCs are adult stem cells that have been genetically reprogrammed to behave like the pluripotent stem cells found in embryos, i.e. can differentiate into any cell type in the human body. This was first completed successfully in mice in 2006 by Shinya Yamanaka and his team (Takahashi et al., 2006), then in humans in 2007 both by Yamanaka (Takahashi et al., 2007), and by James Thomson and his team in America independently (Yu, et al., 2007). Yamanaka and Thomson’s methods were similar. In the report by Yu et
Many scientists believe that embryonic stem cell (ESC) research is the key to curing diseases such as cancer and HIV. Stem cells are so important to biomedical research because they are primitive cells that are capable of replicating indefinitely producing a multitude of different types of cells. This means that one of these pre-determined cells has to potential of becoming any range of over two hundred tissues with epithelial cells to blood and
Stem cell research is the future of medical and biological research and remedies, and it is fascinating to watch the progression of this new and important science as it unfolds. These cells were discovered in mouse embryos in the 1980s, and are remarkable because of their potential to grow into a variety of different kinds of cells within a body. Common in fetuses, and more rare in adult animals of all kinds, stem cells can be manipulated in useful ways to repair many tissues, dividing limitlessly for therapeutic purposes. When a stem cell divides, each new cell has the potential either to remain a stem cell or to differentiate into more specialized tissue, such as nerve, pancreas, bone marrow, or unique blood components. Initially
In the Nature paper “Bidirectional developmental potential in reprogrammed cells with acquired pluripotency”, published in 2014 and now retracted, Haruko Obokata et al. described a new methodology for the conversion of somatic cells into pluripotent cells, without genetic manipulation or DNA transfer. Somatic cells were subjected to sublethal stimuli and, therefore, named “stimulus-triggered acquisition of pluripotency” (STAP). The research consisted in introducing mouse somatic cells into a very acidic solution (low pH) or subjecting the external cell membranes to pressure. These stressful environmental stimuli led the somatic cells to a cell reprogramming. Obokata and colleagues, therefore, presented a fast, simple and cheap method of