Induced pluripotent stem cell

Induced pluripotent stem cells (also known as iPS cells or iPSCs) are a type of pluripotent stem cell that can be generated directly from adult cells. The iPSC technology was pioneered by Shinya Yamanaka’s lab in Kyoto, Japan, who showed in 2006 that the introduction of four specific genes encoding transcription factors could convert adult cells into pluripotent stem cells.[1] He was awarded the 2012 Nobel Prize along with Sir John Gurdon "for the discovery that mature cells can be reprogrammed to become pluripotent." [2]

Pluripotent stem cells hold great promise in the field of regenerative medicine. Because they can propagate indefinitely, as well as give rise to every other cell type in the body (such as neurons, heart, pancreatic, and liver cells), they represent a single source of cells that could be used to replace those lost to damage or disease.

The most well-known type of pluripotent stem cell is the embryonic stem cell. However, since the generation of embryonic stem cells involves destruction (or at least manipulation) [3] of the pre-implantation stage embryo, there has been much controversy surrounding their use. Further, because embryonic stem cells can only be derived from embryos, it has so far not been feasible to create patient-matched embryonic stem cell lines.

Since iPSCs can be derived directly from adult tissues, they not only bypass the need for embryos, but can be made in a patient-matched manner, which means that each individual could have their own pluripotent stem cell line. These unlimited supplies of autologous cells could be used to generate transplants without the risk of immune rejection. While the iPSC technology has not yet advanced to a stage where therapeutic transplants have been deemed safe, iPSCs are readily being used in personalized drug discovery efforts and understanding the patient-specific basis of disease.[4]

Production

See also: Reprogramming
A scheme of the generation of induced pluripotent stem (IPS) cells. (1)Isolate and culture donor cells. (2)Transduce stem cell-associated genes into the cells by viral vectors. Red cells indicate the cells expressing the exogenous genes. (3)Harvest and culture the cells according to ES cell culture, using mitotically inactivated feeder cells (lightgray). (4)A small subset of the transfected cells become iPS cells and generate ES-like colonies.

iPSCs are typically derived by introducing products of specific set of pluripotency-associated genes, or “reprogramming factors”, into a given cell type. The original set of reprogramming factors (also dubbed Yamanaka factors) are the transcription factors Oct4 (Pou5f1), Sox2, cMyc, and Klf4. While this combination is most conventional in producing iPSCs, each of the factors can be functionally replaced by related transcription factors, miRNAs, small molecules, or even non-related genes such as lineage specifiers.

iPSC derivation is typically a slow and inefficient process, taking 1–2 weeks for mouse cells and 3–4 weeks for human cells, with efficiencies around 0.01%–0.1%. 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)

Induced pluripotent stem cells were first generated by Shinya Yamanaka's team at Kyoto University, Japan, in 2006.[1] They hypothesized that genes important to embryonic stem cell (ESC) function might be able to induce an embryonic state in adult cells. 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, Fbx15, could 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 Fbx15.

Similar to ESCs, these iPSCs had unlimited self-renewal and were pluripotent, contributing to lineages from all three germ layers in the context of embryoid bodies, teratomas, and fetal chimeras. However, the molecular makeup of these cells, including gene expression and epigenetic marks, was somewhere between that of a fibroblast and an ESC, and the cells failed to produce viable chimeras when injected into developing embryos.

Second generation (mouse)

In June 2007, three separate research groups, including that of Yamanaka's, a Harvard/University of California, Los Angeles collaboration, and a group at MIT, published studies that substantially improved on the reprogramming approach, giving rise to iPSCs that were indistinguishable from ESCs. 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 Nanog, a gene that is functionally important in ESCs. By using this different strategy, the researchers created iPSCs that were functionally identical to ESCs.[5][6][7][8]

Human induced pluripotent stem cells

Generation from human fibroblasts

Reprogramming of human cells to iPSCs was reported in November 2007 by two independent research groups: Shinya Yamanaka of Kyoto University, Japan, who pioneered the original iPSC method, and James Thomson of University of Wisconsin-Madison who was the first to derive human embryonic stem cells. 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 C-MYC, using a retroviral system,[9] while Thomson and colleagues used a different set of factors, OCT4, SOX2, NANOG, and LIN28, using a lentiviral system.[10]

Generation from additional cell types

Obtaining fibroblasts to produce iPSCs involves a skin biopsy, and there has been a push towards identifying cell types that are more easily accessible.[11][12] In 2008, iPSCs were derived from human keratinocytes, which could be obtained from a single hair pluck.[13][14] In 2010, iPSCs were derived from peripheral blood cells,[15][16] and in 2012, iPSCs were made from renal epithelial cells in the urine.[17]

Other considerations for starting cell type include mutational load (for example, skin cells may harbor more mutations due to UV exposure),[11][12] time it takes to expand the population of starting cells,[11] and the ability to differentiate into a given cell type.[18]

Genes used to produce iPSCs

The generation of iPS cells is crucially dependent on the transcription factors used for the induction.

Oct-3/4 and certain products of the Sox gene family (Sox1, Sox2, Sox3, and Sox15) have been identified as crucial transcriptional regulators involved in the induction process whose absence makes induction impossible. Additional genes, however, including certain members of the Klf family (Klf1, Klf2, Klf4, and Klf5), the Myc family (c-myc, L-myc, and N-myc), Nanog, and LIN28, have been identified to increase the induction efficiency.

Challenges in reprogramming cells to pluripotency

Although the methods pioneered by Yamanaka and others have demonstrated that adult cells can be reprogrammed to iPS cells, there are still challenges associated with this technology:

  1. Low efficiency: in general, the conversion to iPS cells has been incredibly low. For example, the rate at which somatic cells were reprogrammed into iPS cells in Yamanaka's original mouse study was 0.01–0.1%.[1] The low efficiency rate may reflect the need for precise timing, balance, and absolute levels of expression of the reprogramming genes. It may also suggest a need for rare genetic and/or epigenetic changes in the original somatic cell population or in the prolonged culture. However, recently a path was found for efficient reprogramming which required downregulation of the nucleosome remodeling and deacetylation (NuRD) complex. Overexpression of Mbd3, a subunit of NuRD, inhibits induction of iPSCs. Depletion of Mbd3, on the other hand, improves reprogramming efficiency,[22] that results in deterministic and synchronized iPS cell reprogramming (near 100% efficiency within seven days from mouse and human cells).[23]
  2. Genomic Insertion: genomic integration of the transcription factors limits the utility of the transcription factor approach because of the risk of mutations being inserted into the target cell’s genome.[24] A common strategy for avoiding genomic insertion has been to use a different vector for input. Plasmids, adenoviruses, and transposon vectors have all been explored, but these often come with the tradeoff of lower throughput.[25][26][27]
  3. Tumorigenicity: 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 February 2008, scientists 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.[28] In another study, Yamanaka reported that one can create iPSCs without the oncogene c-Myc. The process took longer and was not as efficient, but the resulting chimeras didn't develop cancer.[29] Inactivation or deletion of the tumor suppressor p53, which is a key regulator of cancer, significantly increases reprogramming efficiency.[30] Thus there seems to be a tradeoff between reprogramming efficiency and tumor generation.
  4. Incomplete reprogramming: reprogramming also faces the challenge of completeness. 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.[31]

The table at right summarizes the key strategies and techniques used to develop iPS cells over the past half-decade. Rows of similar colors represents studies that used similar strategies for reprogramming.

This timeline summarizes the key strategies and techniques used to develop iPS cells over the past half-decade. Rows of similar colors represents studies that used similar strategies for reprogramming.

Alternative approaches

Mimicking transcription factors with chemicals

One of the main strategies for avoiding problems (1) and (2) has been to use small compounds that can mimic the effects of transcription factors. These molecule compounds can compensate for a reprogramming factor that does not effectively target the genome or fails at reprogramming for another reason; thus they raise reprogramming efficiency. They also avoid the problem of genomic integration, which in some cases contributes to tumor genesis. Key studies using such strategy were conducted in 2008. Melton et al. studied the effects of histone deacetylase (HDAC) inhibitor valproic acid. They found that it increased reprogramming efficiency 100-fold (compared to Yamanaka’s traditional transcription factor method).[32] The researchers proposed that this compound was mimicking the signaling that is usually caused by the transcription factor c-Myc. A similar type of compensation mechanism was proposed to mimic the effects of Sox2. In 2008, Ding et al. used the inhibition of histone methyl transferase (HMT) with BIX-01294 in combination with the activation of calcium channels in the plasma membrane in order to increase reprogramming efficiency.[33] Deng et al. of Beijing University reported on July 2013 that induced pluripotent stem cells can be created without any genetic modification. They used a cocktail of seven small-molecule compounds including DZNep to induce the mouse somatic cells into stem cells which they called CiPS cells with the efficiency – at 0.2% – comparable to those using standard iPSC production techniques. The CiPS cells were introduced into developing mouse embryos and were found to contribute to all major cells types, proving its pluripotency.[34][35]

Ding et al. demonstrated an alternative to transcription factor reprogramming through the use of drug-like chemicals. By studying the MET (mesenchymal-epithelial transition) process in which fibroblasts are pushed to a stem-cell like state, Ding’s group identified two chemicals – ALK5 inhibitor SB431412 and MEK (mitogen-activated protein kinase) inhibitor PD0325901 – which was found to increase the efficiency of the classical genetic method by 100 fold. Adding a third compound known to be involved in the cell survival pathway, Thiazovivin further increases the efficiency by 200 fold. Using the combination of these three compounds also decreased the reprogramming process of the human fibroblasts from four weeks to two weeks. [36][37]

In April 2009, it was demonstrated that generation of iPS cells is possible without any genetic alteration of the adult cell: a repeated treatment of the cells with certain proteins channeled into the cells via poly-arginine anchors was sufficient to induce pluripotency.[38] The acronym given for those iPSCs is piPSCs (protein-induced pluripotent stem cells).

Alternate vectors

Another key strategy for avoiding problems such as tumor genesis and low throughput has been to use alternate forms of vectors: adenovirus, plasmids, and naked DNA and/or protein compounds.

In 2008, Hochedlinger et al. used an adenovirus to transport the requisite four transcription factors into the DNA of skin and liver cells of mice, resulting in cells identical to ESCs. The adenovirus is unique from other vectors like viruses and retroviruses because it does not incorporate any of its own genes into the targeted host and avoids the potential for insertional mutagenesis.[39] In 2009, Freed et al. demonstrated successful reprogramming of human fibroblasts to iPS cells.[40] Another advantage of using adenoviruses is that they only need to present for a brief amount of time in order for effective reprogramming to take place.

Also in 2008, Yamanaka et al. found that they could transfer the four necessary genes with a plasmid.[41] The Yamanaka group successfully reprogrammed mouse cells by transfection with two plasmid constructs carrying the reprogramming factors; the first plasmid expressed c-Myc, while the second expressed the other three factors (Oct4, Klf4, and Sox2). Although the plasmid methods avoid viruses, they still require cancer-promoting genes to accomplish reprogramming. The other main issue with these methods is that they tend to be much less efficient compared to retroviral methods. Furthermore, transfected plasmids have been shown to integrate into the host genome and therefore they still pose the risk of insertional mutagenesis. Because non-retroviral approaches have demonstrated such low efficiency levels, researchers have attempted to effectively rescue the technique with what is known as the PiggyBac Transposon System. Several studies have demonstrated that this system can effectively deliver the key reprogramming factors without leaving footprint mutations in the host cell genome. The PiggyBac Transposon System involves the re-excision of exogenous genes, which eliminates the issue of insertional mutagenesis. [42]

Stimulus-triggered acquisition of pluripotency cell

In January 2014, two articles were published claiming that a type of pluripotent stem cell can be generated by subjecting the cells to certain types of stress (bacterial toxin, a low pH of 5.7, or physical squeezing); the resulting cells were called STAP cells, for stimulus-triggered acquisition of pluripotency.[43]

In light of difficulties that other labs had replicating the results of the surprising study, in March 2014, one of the co-authors has called for the articles to be retracted.[44] On 4 June 2014, the lead author, Obokata agreed to retract both the papers [45] after she was found to have committed ‘research misconduct’ as concluded in an investigation by RIKEN on 1 April 2014.[46]

RNA molecules

MicroRNAs are short RNA molecules that bind to complementary sequences on messenger RNA and block expression of a gene. Measuring variations in microRNA expression in iPS cells can be used to predict their differentiation potential.[47] Addition of microRNAs can also be used to enhance iPS potential. Several mechanisms have been proposed.[47] ES cell-specific microRNA molecules (such as miR-291, miR-294 and miR-295) enhance the efficiency of induced pluripotency by acting downstream of c-Myc.[48] microRNAs can also block expression of repressors of Yamanaka’s four transcription factors, and there may be additional mechanisms induce reprogramming even in the absence of added exogenous transcription factors.[47]

Identity

Induced pluripotent stem cells are similar to natural pluripotent stem cells, such as embryonic stem (ES) cells, in many aspects, such as the expression of certain stem cell genes and proteins, chromatin methylation patterns, doubling time, embryoid body formation, teratoma formation, viable chimera formation, and potency and differentiability, but the full extent of their relation to natural pluripotent stem cells is still being assessed.[49]

Gene expression and genome-wide H3K4me3 and H3K27me3 were found to be extremely similar between ES and iPS cells.[50] The generated iPSCs were remarkably similar to naturally isolated pluripotent stem cells (such as mouse and human embryonic stem cells, mESCs and hESCs, respectively) in the following respects, thus confirming the identity, authenticity, and pluripotency of iPSCs to naturally isolated pluripotent stem cells:

Safety

Recent achievements and future tasks for safe iPSC-based cell therapy are collected in the review of Okano et al.[62]

Medical research

The task of producing iPS cells continues to be challenging due to the six problems mentioned above. A key tradeoff to overcome is that between efficiency and genomic integration. Most methods that do not rely on the integration of transgenes are inefficient, while those that do rely on the integration of transgenes face the problems of incomplete reprogramming and tumor genesis, although a vast number of techniques and methods have been attempted. Another large set of strategies is to perform a proteomic characterization of iPS cells.[63] Further studies and new strategies should generate optimal solutions to the five main challenges. One approach might attempt to combine the positive attributes of these strategies into an ultimately effective technique for reprogramming cells to iPS cells.

Another approach is the use of iPS cells derived from patients to identify therapeutic drugs able to rescue a phenotype. For instance, iPS cell lines derived from patients affected by ectodermal dysplasia syndrome (EEC), in which the p63 gene is mutated, display abnormal epithelial commitment that could be partially rescued by a small compound[64]

Disease modeling and drug development

An attractive feature of human iPS cells is the ability to derive them from adult patients to study the cellular basis of human disease. Since iPS cells are self-renewing and pluripotent, they represent a theoretically unlimited source of patient-derived cells which can be turned into any type of cell in the body. This is particularly important because many other types of human cells derived from patients tend to stop growing after a few passages in laboratory culture. iPS cells have been generated for a wide variety of human genetic diseases, including common disorders such as Down syndrome and polycystic kidney disease.[65][66] In many instances, the patient-derived iPS cells exhibit cellular defects not observed in iPS cells from healthy patients, providing insight into the pathophysiology of the disease.[67] An international collaborated project, StemBANCC, was formed in 2012 to build a collection of iPS cell lines for drug screening for a variety of disease. Managed by the University of Oxford, the effort pooled funds and resources from 10 pharmaceutical companies and 23 universities. The goal is to generate a library of 1,500 iPS cell lines which will be used in early drug testing by providing a simulated human disease environment.[68] Furthermore, combining hiPSC technology and genetically-encoded voltage and calcium indicators provided a large-scale and high-throughput platform for cardiovascular drug safety screening.[69]

Organ synthesis

A proof-of-concept of using induced pluripotent stem cells (iPSCs) to generate human organ for transplantation was reported by researchers from Japan. Human ‘liver buds’ (iPSC-LBs) were grown from a mixture of three different kinds of stem cells: hepatocytes (for liver function) coaxed from iPSCs; endothelial stem cells (to form lining of blood vessels) from umbilical cord blood; and mesenchymal stem cells (to form connective tissue). This new approach allows different cell types to self-organize into a complex organ, mimicking the process in fetal development. After growing in vitro for a few days, the liver buds were transplanted into mice where the ‘liver’ quickly connected with the host blood vessels and continued to grow. Most importantly, it performed regular liver functions including metabolizing drugs and producing liver-specific proteins. Further studies will monitor the longevity of the transplanted organ in the host body (ability to integrate or avoid rejection) and whether it will transform into tumors.[70][71] Using this method, cells from one mouse could be used to test 1,000 drug compounds to treat liver disease, and reduce animal use by up to 50,000.[72]

Tissue repair

Embryonic cord-blood cells were induced into pluripotent stem cells using plasmid DNA. Using cell surface endothelial/pericytic markers CD31 and CD146, researchers identified 'vascular progenitor', the high-quality, multipotent vascular stem cells. After the iPS cells were injected directly into the vitreous of the damaged retina of mice, the stem cells engrafted into the retina, grew and repaired the vascular vessels.[73][74]

Labelled iPSCs-derived NSCs injected into laboratory animals with brain lesions were shown to migrate to the lesions and some motor function improvement was observed.[75]

Red blood cells

Although a pint of donated blood contains about two trillion red blood cells and over 107 million blood donations are collected globally, there is still a critical need for blood for transfusion. In 2014, type O red blood cells were synthesized at the Scottish National Blood Transfusion Service from iPSC. The cells were induced to become a mesoderm and then blood cells and then red blood cells. The final step was to make them eject their nuclei and mature properly. Type O can be transfused into all patients. Human clinical trials were not expected to begin before 2016.[76]

Clinical trial

The first human clinical trial using autologous iPSCs was approved by the Japan Ministry Health and was to be conducted in 2014 in Kobe. However the trial was suspended after Japan's new regenerative medicine laws came into effect last November.[77] iPSCs derived from skin cells from six patients suffering from wet age-related macular degeneration were to be reprogrammed to differentiate into retinal pigment epithelial (RPE) cells. The cell sheet would be transplanted into the affected retina where the degenerated RPE tissue was excised. Safety and vision restoration monitoring would last one to three years.[78][79] The benefits of using autologous iPSCs are that there is theoretically no risk of rejection and it eliminates the need to use embryonic stem cells.[79]

See also

References

  1. 1 2 3 Takahashi, K; Yamanaka, S (2006). "Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors". Cell. 126 (4): 663–76. doi:10.1016/j.cell.2006.07.024. PMID 16904174.
  2. "The Nobel Prize in Physiology or Medicine – 2012 Press Release". Nobel Media AB. 8 October 2012.
  3. Klimanskaya; et al. (2006). "Human embryonic stem cell lines derived from single blastomeres". Nature. Nature. 444 (7118): 484–485. doi:10.1038/nature05142. PMID 16929302.
  4. Hockemeyer, D; Jaenisch, R (5 May 2016). "Induced Pluripotent Stem Cells Meet Genome Editing.". Cell stem cell. 18 (5): 573–86. PMC 4871596Freely accessible. PMID 27152442.
  5. Okita, K; Ichisaka, T; Yamanaka, S (2007). "Generation of germline-competent induced pluripotent stem cells". Nature. 448 (7151): 313–7. doi:10.1038/nature05934. PMID 17554338.(subscription required)
  6. Wernig, M; Meissner, A; Foreman, R; Brambrink, T; Ku, M; Hochedlinger, K; Bernstein, BE; Jaenisch, R (2007). "In vitro reprogramming of fibroblasts into a pluripotent ES-cell-like state". Nature. 448 (7151): 318–24. doi:10.1038/nature05944. PMID 17554336.
  7. Maherali N, et al. (2007). "Directly reprogrammed fibroblasts show global epigenetic remodeling and widespread tissue contribution". Cell Stem Cell. 1 (1): 55–70. doi:10.1016/j.stem.2007.05.014. PMID 18371336.
  8. Generations of iPSCs and related references
  9. Takahashi K, et al. (2007). "Induction of Pluripotent Stem Cells from Adult Human Fibroblasts by Defined Factors". Cell. 131 (5): 861–872. doi:10.1016/j.cell.2007.11.019. PMID 18035408.
  10. Yu J, Vodyanik MA, et al. (2007). "Induced Pluripotent Stem Cell Lines Derived from Human Somatic Cells". Science. 318 (5858): 1917–1920. doi:10.1126/science.1151526. PMID 18029452.
  11. 1 2 3 Yamanaka, S (2 July 2010). "Patient-specific pluripotent stem cells become even more accessible.". Cell stem cell. 7 (1): 1–2. PMID 20621038.
  12. 1 2 Maherali, N; Hochedlinger, K (4 December 2008). "Guidelines and techniques for the generation of induced pluripotent stem cells.". Cell stem cell. 3 (6): 595–605. PMID 19041776.
  13. Maherali, N; et al. (11 September 2008). "A high-efficiency system for the generation and study of human induced pluripotent stem cells.". Cell stem cell. 3 (3): 340–5. PMID 18786420.
  14. Aasen, T; et al. (November 2008). "Efficient and rapid generation of induced pluripotent stem cells from human keratinocytes.". Nature biotechnology. 26 (11): 1276–84. PMID 18931654.
  15. Staerk, J; et al. (2 July 2010). "Reprogramming of human peripheral blood cells to induced pluripotent stem cells.". Cell stem cell. 7 (1): 20–4. PMID 20621045.
  16. Loh, YH; et al. (2 July 2010). "Reprogramming of T cells from human peripheral blood.". Cell stem cell. 7 (1): 15–9. PMID 20621044.
  17. Zhou, T; et al. (December 2012). "Generation of human induced pluripotent stem cells from urine samples.". Nature protocols. 7 (12): 2080–9. PMID 23138349.
  18. Polo, JM; et al. (August 2010). "Cell type of origin influences the molecular and functional properties of mouse induced pluripotent stem cells.". Nature biotechnology. 28 (8): 848–55. PMID 20644536.
  19. Ali, P. S.; Ghoshdastider, U; Hoffmann, J; Brutschy, B; Filipek, S (2012). "Recognition of the let-7g miRNA precursor by human Lin28B". FEBS Letters. 586 (22): 3986–90. doi:10.1016/j.febslet.2012.09.034. PMID 23063642.
  20. Yu, J; Vodyanik, MA; Smuga-Otto, K; Antosiewicz-Bourget, J; Frane, JL; Tian, S; Nie, J; Jonsdottir, GA; Ruotti, V; Stewart, R; Slukvin, II; Thomson, JA (21 December 2007). "Induced pluripotent stem cell lines derived from human somatic cells.". Science (New York, N.Y.). 318 (5858): 1917–20. PMID 18029452.
  21. Maekawa M, et al. (2011). "Direct reprogramming of somatic cells is promoted by maternal transcription factor Glis1". Nature. 474 (7350): 225–229. doi:10.1038/nature10106. PMID 21654807.
  22. Luo M, et al. "& Tao, W., Lu, Z., Grummt, I. (2013), NuRD Blocks Reprogramming of Mouse Somatic Cells into Pluripotent Stem Cells". STEM CELLS. 31: 1278–1286. doi:10.1002/stem.1374.
  23. Yoach Rais, Asaf Zviran, Shay Geula, et al. (2013) Deterministic direct reprogramming of somatic cells to pluripotency. Nature, doi:10.1038/nature12587
  24. Selvaraj V, Plane JM, Williams AJ, Deng W (April 2010). "Switching cell fate: the remarkable rise of induced pluripotent stem cells and lineage reprogramming technologies". Trends in Biotechnology. 28 (4): 214–23. doi:10.1016/j.tibtech.2010.01.002. PMC 2843790Freely accessible. PMID 20149468.
  25. Okita, K; Nakagawa, M.; Hyenjong, H.; Ichisaka, T.; Yamanaka, S. (2008). "Generation of mouse induced pluripotent stem cells without viral vectors". Science. 322 (5903): 949–953. doi:10.1126/science.1164270. PMID 18845712.
  26. Stadtfeld, M; Nagaya, M; Utikal, J; Weir, G; Hochedlinger, K (7 November 2008). "Induced pluripotent stem cells generated without viral integration.". Science (New York, N.Y.). 322 (5903): 945–9. PMID 18818365.
  27. Woltjen, K; Michael, IP; Mohseni, P; Desai, R; Mileikovsky, M; Hämäläinen, R; Cowling, R; Wang, W; Liu, P (2009). "piggyBac transposition reprograms fibroblasts to induced pluripotent stem cells". Nature. 458 (7239): 766–770. doi:10.1038/nature07863. PMID 19252478.
  28. Kaplan, Karen (2009-03-06). "Cancer threat removed from stem cells, scientists say". Los Angeles Times.
  29. Swaminathan, Nikhil (2007-11-30). "Stem Cells – This Time Without the Cancer". Scientific American News. Retrieved 2007-12-11.
  30. RM, Mario; Strati, Katerina; Li, Han; Murga, Matilde; Blanco, Raquel; Ortega, Sagrario; Fernandez-Capetillo, Oscar; Serrano, Manuel; Blasco, Maria A. (2009). "A p53-mediated DNA damage response limits reprogramming to ensure iPS cell genomic integrity". Nature. 460 (7259): 1149–1153. doi:10.1038/nature08287. PMID 19668189.
  31. Zhao, XY; Li, Wei; Lv, Zhuo; Liu, Lei; Tong, Man; Hai, Tang; Hao, Jie; Guo, Chang-Long; Ma, Qing-wen (2009). "iPS cells produce viable mice through tetraploid complementation". Nature. 461 (7260): 86–90. doi:10.1038/nature08267. PMID 19672241.
  32. Huangfu D, Maehr R, Guo W, et al. (2008). "Induction of pluripotent stem cells by defined factors is greatly improved by small-molecule compounds". Nat Biotechnol. 26 (7): 795–7. doi:10.1038/nbt1418. PMID 18568017.
  33. Desponts, Shi; Desponts, Caroline; Do, Jeong Tae; Hahm, Heung Sik; Schöler, Hans R.; Ding, Sheng (November 2008). "Induction of pluripotent stem cells from mouse embryonic fibroblasts by Oct4 and Klf4 with small-molecule compounds". Cell Stem Cell. 3 (5): 568–74. doi:10.1016/j.stem.2008.10.004. PMID 18983970.
  34. Cyranoski, David (18 July 2013). "Stem cells reprogrammed using chemicals alone". Nature. doi:10.1038/nature.2013.13416. Retrieved 22 July 2013.
  35. Deng, Hongkui; Hou, Pingping; Li, Yanqin; Zhang, Xu; Liu, Chun; Guan, Jingyang; Li, Honggang; Zhao, Ting; Ye, Junqing (18 July 2013). "Pluripotent Stem Cells Induced from Mouse Somatic Cells by Small-Molecule Compounds". Science. sciencemag.org. 341: 651–654. doi:10.1126/science.1239278. PMID 23868920.
  36. "Major Step In Making Better Stem Cells From Adult Tissue". Science Daily. 19 October 2009. Retrieved 30 September 2013.
  37. Lin, Tongxiang; Ambasudhan, Rajesh; Yuan, Xu; Li, Wenlin; Hilcove, Simon; Abujarour, Ramzey; Lin, Xiangyi; Hahm, Heung Sol; Hao, Ergeng; Hayek, Alberto; Ding, Sheng (2009). "A chemical platform for improved induction of human iPSCs". Nature Methods. Nature. 6: 805–808. doi:10.1038/nmeth.1393.
  38. 1 2 Zhou H, Wu S, Joo JY, et al. (May 2009). "Generation of Induced Pluripotent Stem Cells Using Recombinant Proteins". Cell Stem Cell. 4 (5): 381–4. doi:10.1016/j.stem.2009.04.005. PMID 19398399. Retrieved April 23, 2009.
  39. Desponts, Shi; Desponts, Caroline; Do, Jeong Tae; Hahm, Heung Sik; Schöler, Hans R.; Ding, Sheng (2008). "Induction of pluripotent stem cells from mouse embryonic fibroblasts by Oct4 and Klf4 with small-molecule compounds". Cell Stem Cell. 3 (5): 568–74. doi:10.1016/j.stem.2008.10.004. PMID 18983970.
  40. Zhou, Wi; Freed, Curt R. (2009). "Adenoviral gene delivery can reprogram human fibroblasts to induced pluripotent stem cells". Stem Cells. 27 (11): 2667–74. doi:10.1002/stem.201. PMID 19697349.
  41. Yamanaka, K.; Nakagawa, M.; Hyenjong, H.; Ichisaka, T.; Yamanaka, S. (2008). "Generation of Mouse Induced Pluripotent Stem Cells Without Viral Vectors". Science. 322 (5903): 949–53. doi:10.1126/science.1164270. PMID 18845712.
  42. citation needed
  43. David Cyranoski for Nature News. January 29, 2014 Acid bath offers easy path to stem cells
  44. Tracy Vence for the Scientist. March 11, 2014 Call for STAP Retractions
  45. Elaine Lies (4 June 2014). "Japan researcher agrees to withdraw disputed stem cell paper". Reuters. Retrieved 4 June 2014.
  46. Press Release (1 April 2014). "Report on STAP Cell Research Paper Investigation". RIKEN. Retrieved 2 June 2014.
  47. 1 2 3 Bao Xichen; Zhu Xihua; Liao Baojian; et al. (Apr 2013). "& Miguel A Esteban (2013) MicroRNAs in somatic cell reprogramming". Current Opinion in Cell Biology. 25 (2): 208–214. doi:10.1016/j.ceb.2012.12.004. PMID 23332905.
  48. Judson, RL. "Embryonic stem cell-specific microRNAs promote induced pluripotency". Source the Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, California, USA.
  49. Takahashi K, Yamanaka S (August 2006). "Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors". Cell. 126 (4): 663–76. doi:10.1016/j.cell.2006.07.024. PMID 16904174.
  50. Guenther, M.G.; Frmapton, G.M.; Soldner, F.; Hockemeyer, D.; Mitalipova, M.; Jaenisch, R.; Young, R.A. (2010). "Chromatin structure and gene expression programs of human embryonic and induced pluripotent stem cells.". Cell Stem Cell. 7 (?): 249–257. doi:10.1016/j.stem.2010.06.015. PMC 3010384Freely accessible. PMID 20682450.
  51. Zhao, Xiao-Yang; Li, Wei; Lv, Zhuo; Liu, Lei; Tong, Man; Hai, Tang; Hao, Jie; Guo, Chang-Long; Ma, Qing-wen (2009). "iPS cells produce viable mice through tetraploid complementation". Nature. 461 (7260): 86–90. doi:10.1038/nature08267. PMID 19672241.
  52. Kang, Lan; Wang, Jianle; Zhang, Yu; Kou, Zhaohui; Gao, Shaorong (2009). "iPS Cells Can Support Full-Term Development of Tetraploid Blastocyst-Complemented Embryos". Cell Stem Cell. 5 (2): 135–138. doi:10.1016/j.stem.2009.07.001. PMID 19631602.
  53. Michael J. Boland; et al. (2009). "Adult mice generated from induced pluripotent stem cells". Nature. 461 (7260): 91–4. doi:10.1038/nature08310. PMID 19672243.
  54. Lister R, Pelizzola M, Kida YS, Hawkins D, Nery JR, et al. (2011). "Hotspots of aberrant epigenomic reprogramming in human induced pluripotent stem cells". Nature. 471 (7336): 68–73. doi:10.1038/nature09798. PMC 3100360Freely accessible. PMID 21289626.
  55. Knoepfler, Paul S. (2009). "Deconstructing Stem Cell Tumorigenicity: A Roadmap to Safe Regenerative Medicine". Stem Cells. 27 (5): 1050–1056. doi:10.1002/stem.37. PMC 2733374Freely accessible. PMID 19415771.
  56. Satoshi, Nori (2011). "Grafted Human-induced Pluripotent Stem-Cell–Derived Neurospheres Promote Motor Functional Recovery After Spinal Cord Injury In Mice". PNAS. 108 (40): 16825–16830. doi:10.1073/pnas.1108077108. PMC 3189018Freely accessible. PMID 21949375.
  57. Nori, Satoshi; Okada, Yohei; Nishimura, Soraya; Sasaki, Takashi; Itakura, Go; Kobayashi, Yoshiomi; Renault-Mihara, Francois; Shimizu, Atsushi; Koya, Ikuko (2015-10-03). "Long-Term Safety Issues of iPSC-Based Cell Therapy in a Spinal Cord Injury Model: Oncogenic Transformation with Epithelial-Mesenchymal Transition". Stem Cell Reports. 4 (3): 360–373. doi:10.1016/j.stemcr.2015.01.006. ISSN 2213-6711. PMC 4375796Freely accessible. PMID 25684226.
  58. Aoi, T.; Yae, K.; Nakagawa, M.; Ichisaka, T.; Okita, K.; Takahashi, K.; Chiba, T.; Yamanaka, S. (2008). "Generation of Pluripotent Stem Cells from Adult Mouse Liver and Stomach Cells". Science. 321 (5889): 699–702. doi:10.1126/science.1154884. PMID 18276851.
  59. Ivan Gutierrez-Aranda.; et al. (2010). "Human Induced Pluripotent Stem Cells Develop Teratoma More Efficiently and Faster than Human Embryonic Stem Cells Regardless of the Site of Injection". Stem Cells. 28 (9): 1568–1570. doi:10.1002/stem.471. PMC 2996086Freely accessible. PMID 20641038.
  60. Zhao T, Zhang ZN, Rong Z, Xu Y (2011). "Immunogenicity of induced pluripotent stem cells". Nature. 474 (7350): 212–5. doi:10.1038/nature10135. PMID 21572395.
  61. Araki, Ryoko; Mashiro Uda; Yuko Hoki; Misato Sunayama; Miki Nakamura; Shunsuke Ando; Mayumi Sugiura; Hisashi Ideno; Akemi Shimada; Akira Nifuji; Masume Abe (7 February 2013). "Negligible immunogenicity of terminally differentiated cells derived from induced pluripotent or embroyonic stem cells". Nature. 494 (7435): 100–106. doi:10.1038/nature11807. PMID 23302801.
  62. Okano Hideyuki; Nakamura Masaya; Yoshida Kenji; et al. (Feb 2013). "& Kyoko Miura (2013) Steps Toward Safe Cell Therapy Using Induced Pluripotent Stem Cells". Circulation Research. 112: 523–533. doi:10.1161/CIRCRESAHA.111.256149. PMID 23371901.
  63. Boland, MY; Hazen, Jennifer L.; Nazor, Kristopher L.; Rodriguez, Alberto R.; Gifford, Wesley; Martin, Greg; Kupriyanov, Sergey; Baldwin, Kristin K. (2009). "Adult mice generated from induced pluripotent stem cells". Nature. 461 (7260): 91–4. doi:10.1038/nature08310. PMID 19672243.
  64. Shalom-Feuerstein R et al. Impaired epithelial differentiation of induced pluripotent stem cells from EEC patients is rescued by APR-246/PRIMA-1MET. P.N.A.S. 2012 http://minus.com/lbmC3TVGDx350s
  65. Park, IH; Arora, N; Huo, H; Maherali, N; Ahfeldt, T; Shimamura, A; Lensch, MW; Cowan, C; Hochedlinger, K; Daley, GQ (Sep 5, 2008). "Disease-specific induced pluripotent stem cells.". Cell. 134 (5): 877–86. doi:10.1016/j.cell.2008.07.041. PMC 2633781Freely accessible. PMID 18691744.
  66. Freedman, BS; Lam, AQ; Sundsbak, JL; Iatrino, R; Su, X; Koon, SJ; Wu, M; Daheron, L; Harris, PC; Zhou, J; Bonventre, JV (October 2013). "Reduced ciliary polycystin-2 in induced pluripotent stem cells from polycystic kidney disease patients with PKD1 mutations.". Journal of the American Society of Nephrology : JASN. 24 (10): 1571–86. doi:10.1681/ASN.2012111089. PMID 24009235.
  67. Grskovic, M; Javaherian, A; Strulovici, B; Daley, GQ (Nov 11, 2011). "Induced pluripotent stem cells--opportunities for disease modelling and drug discovery.". Nature reviews. Drug discovery. 10 (12): 915–29. doi:10.1038/nrd3577. PMID 22076509.
  68. Gerlin, Andrea (5 December 2012). "Roche, Pfizer, Sanofi Plan $72.7 Million Stem-Cell Bank". Bloomberg.com. Retrieved 23 December 2012.
  69. Shinnawi, Rami; Huber, I; Maizels, L; Shaheen, N; Gepstein, A; Arbel, G; Tijsen, A; Gepstein, L (2015). "Monitoring human-induced pluripotent stem cell-derived cardiomyocytes with genetically encoded calcium and voltage fluorescent reporters.". Stem Cell Reports. 5 (4): 582–596. doi:10.1016/j.stemcr.2015.08.009. PMC 4624957Freely accessible. PMID 26372632.
  70. Baker, Monya (3 July 2013). "Miniature human liver grown in mice". Nature.com. Retrieved 19 July 2013.
  71. Takebe, Takanori; Sekine, Keisuke; Enomura, Masahiro; Koike, Hiroyuki; Kimura, Masaki; Ogaeri, Takurnori; Zhang, Ran-Ran; Ueno, Yasuharu; Zheng, Yun-Wen (3 July 2013). "Vascularized and functional human liver from an iPSC-derived organ bud transplant". Nature. 499: 481–484. doi:10.1038/nature12271.
  72. Mini-Livers May Reduce Animal Testing
  73. Mullin, Emily (28 January 2014). "Researchers repair retinas in mice with virus-free stem cells". fiercebiotech.com. Retrieved 17 February 2014.
  74. Zambidis, Elias; Lutty, Gerard; Park, Tea Soon; Bhutto, Imran; et al. (2014). "Vascular Progenitors From Cord Blood-Derived Induced Pluripotent Stem Cells Possess Augmented Capacity for Regenerating Ischemic Retinal Vasculature". Circulation. American Heart Association. 129 (3): 359–372. doi:10.1161/CIRCULATIONAHA.113.003000.
  75. Hailiang T, et al. (2013). "Tracking Induced Pluripotent Stem Cells-Derived Neural Stem Cells in the Central Nervous System of Rats and Monkeys". Cellular Reprogramming. 15: 435–442.
  76. "First transfusions of "manufactured" blood planned for 2016". Gizmag.com. Retrieved 2014-04-23.
  77. Garber, Ken. "RIKEN suspends first clinical trial involving induced pluripotent stem cells". Nature Biotechnology. 33 (9): 890–891. doi:10.1038/nbt0915-890.
  78. Riken Center for Developmental Biology. "Information on p=roposed pilot study of the safety and feasibility of transplantation of autologous hiPSC-derived retinal pigment epithelium (RPE) cell sheets in patients with neovascular age-related macular degeneration". Research. Archived from the original on 26 June 2013. Retrieved 23 July 2013.
  79. 1 2 Gallagher, James (19 July 2013). "Pioneering adult stem cell trial approved by Japan". BBC News. Retrieved 23 July 2013.

External links

Wikimedia Commons has media related to Induced pluripotent stem cells.
This article is issued from Wikipedia - version of the 12/3/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.