Stem cell term paper

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Stem cell term paper

Stem cell term paper

Reprogramming A scheme of the generation of induced pluripotent stem IPS cells. Red cells indicate the cells expressing the exogenous genes. The original set of reprogramming factors also dubbed Yamanaka factors are the transcription factors Oct4 Pou5f1Sox2cMycand Klf4.

While this combination is most conventional in producing iPSCs, each of the factors can be Stem cell term paper replaced by related transcription factors, miRNAssmall molecules, or even non-related genes such as lineage specifiers.

However, considerable advances have been made in improving the efficiency and the time it takes to obtain iPSCs. Upon introduction of reprogramming factors, cells begin to form colonies that resemble pluripotent stem cells, which can be isolated based on their morphology, conditions that select for their growth, or through expression of surface markers or reporter genes.

First generation mouse [ edit ] Induced pluripotent stem cells were first generated by Shinya Yamanaka 's team at Kyoto UniversityJapan, in They chose twenty-four genes previously identified as important in ESCs and used retroviruses to deliver these genes to mouse fibroblasts.

The fibroblasts were engineered so that any cells reactivating the ESC-specific gene, Fbx15could be isolated using antibiotic selection. Upon delivery of all twenty-four factors, ESC-like colonies emerged that reactivated the Fbx15 reporter and could propagate indefinitely.

To identify the genes necessary for reprogramming, the researchers removed one factor at a time from the pool of twenty-four. By this process, they identified four factors, Oct4, Sox2, cMyc, and Klf4, which were each necessary and together sufficient to generate ESC-like colonies under selection for reactivation of Fbx Unlike the first generation of iPSCs, these second generation iPSCs produced viable chimeric mice and contributed to the mouse germline, thereby achieving the 'gold standard' for pluripotent stem cells.

These second-generation iPSCs were derived from mouse fibroblasts by retroviral-mediated expression of the same four transcription factors Oct4, Sox2, cMyc, Klf4. However, instead of using Fbx15 to select for pluripotent cells, the researchers used Nanoga gene that is functionally important in ESCs.

With the same principle used in mouse reprogramming, Yamanaka's group successfully transformed human fibroblasts into iPSCs with the same four pivotal genes, Oct4, Sox2, Klf4, and cMyc, using a retroviral system, [11] while Thomson and colleagues used a different set of factors, Oct4, Sox2, Nanog, and Lin28, using a lentiviral system.

Additional genes, however, including certain members of the Klf family Klf1, Klf2, Klf4, and Klf5the Myc family c-myc, L-myc, and N-mycNanogand LIN28have been identified to increase the induction efficiency. While Sox2 was the initial gene used for induction by Yamanaka et al. Sox1 yields iPS cells with a similar efficiency as Sox2, and genes Sox3Sox15and Sox18 also generate iPS cells, although with decreased efficiency.

Klf4 of the Klf family of transcription factors was initially identified by Yamanaka et al. However, Thomson et al. Klf2 and Klf4 were found to be factors capable of generating iPS cells, and related genes Klf1 and Klf5 did as well, although with reduced efficiency. The Myc family of transcription factors are proto-oncogenes implicated in cancer.

N-myc and L-myc have been identified to induce instead of c-myc with similar efficiency. Therefore, it was surprising when Yamanaka et al. LIN28 is an mRNA binding protein [21] expressed in embryonic stem cells and embryonic carcinoma cells associated with differentiation and proliferation.

Stem cell term paper

It poses numerous advantages when used instead of C-myc. For example, the rate at which somatic cells were reprogrammed into iPS cells in Yamanaka's original mouse study was 0. However, recently a path was found for efficient reprogramming which required downregulation of the nucleosome remodeling and deacetylation NuRD complex.

Plasmidsadenovirusesand transposon vectors have all been explored, but these often come with the tradeoff of lower throughput. Depending on the methods used, reprogramming of adult cells to obtain iPSCs may pose significant risks that could limit their use in humans. For example, if viruses are used to genomically alter the cells, the expression of oncogenes cancer-causing genes may potentially be triggered.

In Februaryscientists announced the discovery of a technique that could remove oncogenes after the induction of pluripotency, thereby increasing the potential use of iPS cells in human diseases. The process took longer and was not as efficient, but the resulting chimeras didn't develop cancer.

This is particularly challenging because the genome-wide epigenetic code must be reformatted to that of the target cell type in order to fully reprogram a cell. However, three separate groups were able to find mouse embryonic fibroblast MEF -derived iPS cells that could be injected into tetraploid blastocysts and resulted in the live birth of mice derived entirely from iPS cells, thus ending the debate over the equivalence of embryonic stem cells ESCs and iPS with regard to pluripotency.

Rows of similar colors represent studies that used similar strategies for reprogramming.The term cloning of stem cell is used by scientists to describe many different processes that involve making duplicates of the different types of stem cells.

Shh! Top 10 stem cell clinic secrets kept from patients - The Niche

In different types of cases, stem cells are duplicated for scientific study and no new results were found during the experiment of trying to. A primitive neoplasm composed predominantly of nonhost cells was detected in the thoracic spinal cord and thecal sac of a year-old man who had received experimental stem-cell treatment from.

How to cite this article: Jewett A, Tseng HC. Tumor Induced Inactivation of Natural Killer Cell Cytotoxic Function; Implication in Growth, Expansion and Differentiation of Cancer Stem Cells. We assessed the feasibility of transplanting a sheet of retinal pigment epithelial (RPE) cells differentiated from induced pluripotent stem cells (iPSCs) in a patient with neovascular age-related.

An emerging stem-cell-derived treatment designed to preserve and potentially restore vision in people with retinitis pigmentosa (RP) has demonstrated a favorable safety profile in an ongoing Phase I/II clinical trial at the University of California, Irvine. The therapy is being developed by the.

Paul, I’ve just submitted a paper for publication in an ophthalmic journal on a proposed model for pricing stem cell and gene therapy treatments for use in the eye, based on .

Stem Cell Assays – Reproducible Research on Stem Cells