Home About us Contact
|
Home About us Contact | ||
|
|
||
Induced Pluripotent Stem Cells (induced + pluripotent_stem_cell)
Selected AbstractsInduced pluripotent stem cells (iPSCs): the emergence of a new champion in stem cell technology-driven biomedical applicationsJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 6 2010Anjan Kumar Das Abstract Pluripotent stem cells possess the unique property of differentiating into all other cell types of the human body. Further, the discovery of induced pluripotent stem cells (iPSCs) in 2006 has opened up new avenues in clinical medicine. In simple language, iPSCs are nothing but somatic cells reprogrammed genetically to exhibit pluripotent characteristics. This process utilizes retroviruses/lentiviruses/adenovirus/plasmids to incorporate candidate genes into somatic cells isolated from any part of the human body. It is also possible to develop disease-specific iPSCs which are most likely to revolutionize research in respect to the pathophysiology of most debilitating diseases, as these can be mimicked ex vivo in the laboratory. These models can also be used to study the safety and efficacy of known drugs or potential drug candidates for a particular diseased condition, limiting the need for animal studies and considerably reducing the time and money required to develop new drugs. Recently, functional neurons, cardiomyocytes, pancreatic islet cells, hepatocytes and retinal cells have been derived from human iPSCs, thus re-confirming the pluripotency and differentiation capacity of these cells. These findings further open up the possibility of using iPSCs in cell replacement therapy for various degenerative disorders. In this review we highlight the development of iPSCs by different methods, their biological characteristics and their prospective applications in regenerative medicine and drug screening. We further discuss some practical limitations pertaining to this technology and how they can be averted for the betterment of human life. Copyright © 2010 John Wiley & Sons, Ltd. [source] Porcine induced pluripotent stem cells may bridge the gap between mouse and human iPSIUBMB LIFE, Issue 4 2010Miguel A. Esteban Abstract Recently, three independent laboratories reported the generation of induced pluripotent stem cells (iPSCs) from pig (Sus scrofa). This finding sums to the growing list of species (mouse, human, monkey, and rat, in this order) for which successful reprogramming using exogenous factors has been achieved, and multiple others are possibly forthcoming. But apart from demonstrating the universality of the network identified by Shinya Yamanaka, what makes the porcine model so special? On one side, pigs are an agricultural commodity and have an easy and affordable maintenance compared with nonhuman primates that normally need to be imported. On the other side, resemblance (for example, size of organs) of porcine and human physiology is striking and because pigs are a regular source of food the ethical concerns that still remain in monkeys are not applicable. Besides, the prolonged lifespan of pigs compared with other domestic species can allow exhaustive follow up of side effects after transplantation. Porcine iPSCs may thus fill the gap between the mouse model, which due to its ease is preferred for mechanistic studies, and the first clinical trials using iPSCs in humans. However, although these studies are relevant and have created significant interest they face analogous problems that we discuss herein together with potential new directions. © 2010 IUBMB IUBMB Life, 62(4): 277,282, 2010 [source] Induced pluripotent stem cells (iPSCs): the emergence of a new champion in stem cell technology-driven biomedical applicationsJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 6 2010Anjan Kumar Das Abstract Pluripotent stem cells possess the unique property of differentiating into all other cell types of the human body. Further, the discovery of induced pluripotent stem cells (iPSCs) in 2006 has opened up new avenues in clinical medicine. In simple language, iPSCs are nothing but somatic cells reprogrammed genetically to exhibit pluripotent characteristics. This process utilizes retroviruses/lentiviruses/adenovirus/plasmids to incorporate candidate genes into somatic cells isolated from any part of the human body. It is also possible to develop disease-specific iPSCs which are most likely to revolutionize research in respect to the pathophysiology of most debilitating diseases, as these can be mimicked ex vivo in the laboratory. These models can also be used to study the safety and efficacy of known drugs or potential drug candidates for a particular diseased condition, limiting the need for animal studies and considerably reducing the time and money required to develop new drugs. Recently, functional neurons, cardiomyocytes, pancreatic islet cells, hepatocytes and retinal cells have been derived from human iPSCs, thus re-confirming the pluripotency and differentiation capacity of these cells. These findings further open up the possibility of using iPSCs in cell replacement therapy for various degenerative disorders. In this review we highlight the development of iPSCs by different methods, their biological characteristics and their prospective applications in regenerative medicine and drug screening. We further discuss some practical limitations pertaining to this technology and how they can be averted for the betterment of human life. Copyright © 2010 John Wiley & Sons, Ltd. [source] AID in reprogramming: Quick and efficientBIOESSAYS, Issue 5 2010Identification of a key enzyme called AID, its activity in DNA demethylation, may help to overcome a pivotal epigenetic barrier in reprogramming somatic cells toward pluripotency Abstract Current methods of reprogramming differentiated cells into induced pluripotent stem cells remain slow and inefficient. In a recent report published online in Nature, Bhutani et al.1 developed a cell fusion strategy, achieving quick and efficient reprogramming toward pluripotency. Using this assay, they identified an immune system protein called activation-induced cytidine deaminase, or AID, which unexpectedly is actually able to "aid" in reprogramming due to its involvement in DNA demethylation that is required for induction of the two key pluripotency genes, Oct4 and Nanog. More recently, Popp et al.2 also reported online in Nature that AID is important for complete cell reprogramming in mammals. Together, these findings provide new insights into how cells are reprogrammed, identify the specific role of AID in cell fate reversal, and advance the field of regenerative medicine. [source] Cell-free production of transducible transcription factors for nuclear reprogramming,BIOTECHNOLOGY & BIOENGINEERING, Issue 6 2009William C. Yang Abstract Ectopic expression of a defined set of transcription factors chosen from Oct3/4, Sox2, c-Myc, Klf4, Nanog, and Lin28 can directly reprogram somatic cells to pluripotency. These reprogrammed cells are referred to as induced pluripotent stem cells (iPSCs). To date, iPSCs have been successfully generated using lentiviruses, retroviruses, adenoviruses, plasmids, transposons, and recombinant proteins. Nucleic acid-based approaches raise concerns about genomic instability. In contrast, a protein-based approach for iPSC generation can avoid DNA integration concerns as well as provide greater control over the concentration, timing, and sequence of transcription factor stimulation. Researchers recently demonstrated that polyarginine peptide conjugation can deliver recombinant protein reprogramming factor (RF) cargoes into cells and reprogram somatic cells into iPSCs. However, the protein-based approach requires a significant amount of protein for the reprogramming process. Producing fusion RFs in the large amounts required for this approach using traditional heterologous in vivo production methods is difficult and cumbersome since toxicity, product aggregation, and proteolysis by endogenous proteases limit yields. In this work, we show that cell-free protein synthesis (CFPS) is a viable option for producing soluble and functional transducible transcription factors for nuclear reprogramming. We used an E. coli -based CFPS system to express the above set of six human RFs as fusion proteins, each with a nona-arginine (R9) protein transduction domain. Using the flexibility offered by the CFPS platform, we successfully addressed proteolysis and protein solubility problems to produce full-length and soluble R9-RF fusions. We subsequently showed that R9-Oct3/4, R9-Sox2, and R9-Nanog exhibit cognate DNA-binding activities, R9-Nanog translocates across the plasma and nuclear membranes, and R9-Sox2 exerts transcriptional activity on a known downstream gene target. Biotechnol. Bioeng. 2009; 104: 1047,1058. © 2009 Wiley Periodicals, Inc. [source] Special focus: Cell and protein manipulationBIOTECHNOLOGY JOURNAL, Issue 2 2009Article first published online: 18 FEB 200 Synthetic biotechnology: The challenge Screening tool for induced pluripotent stem cells Method to limit oncogene expression to stem cells Intravital two-photon microscopy to solve meningitis mystery Electrostatic forces involved in a packaging motor Simulated Raman scattering microscopy offers high sensitivity in real-time imaging Alternative way to save brain cells after stroke or head trauma [source] | ||||||||||||||||||||||