Butyrate greatly enhances derivation of human induced pluripotent stem cells by promoting epigenetic remodeling and the expression of pluripotency associated genes prashant mali, a,b binkuan chou,a,c jonathan yen,a,b zhaohui ye,a,d,e jizhong zou,a,e sarah dowey,a,e robert a. Epigenetics of induced pluripotency, the sevenheaded dragon. Jul 19, 2010 somatic cell nuclear transfer and transcriptionfactorbased reprogramming revert adult cells to an embryonic state, and yield pluripotent stem cells that can generate all tissues. Reprogramming of somatic cells involves epigenetic changes in the pattern of histone modifications and dna methylations. A new epigenetic barrier to induced pluripotent stem cells. Finally, we briefly discuss epigenetic heterogeneity among pluripotent stem cell lines and the influence of epigenetic patterns on genome topology. While extended culturing exposes cells to the risk of accumulation of genetic defects. Mar 29, 20 induced pluripotency was initially demonstrated by reprogramming fibroblasts with four tfs. Reprogramming intermediates isolated based on combinations of the aforementioned markers have an increased probability to form ipsc colonies stadtfeld et al. Embryonic stem cell and induced pluripotent stem cell. Previous studies have shown that induced pluripotent stem cells ipscs can be derived from fibroblasts by ectopic expression of four transcription factors, oct4, sox2, klf4 and cmyc using various methods.
Laurent pluripotent stem cells pscs express a distinctive set of micrornas mirnas. We critically discuss the criteria for assessing reprogramming at the functional and molecular levels using different approaches, and speculate on the molecular mediators that might fa cilitate reprogramming and the maintenance of pluripotency. During cellular reprogramming, the epigenome of a somatic cell is reset to a state compatible with pluripotency maintenance. However, questions remain on whether the epigenetic reprogramming is complete or if there are some recurring ipsc speci. Reprogramming adult cells into induced pluripotency with. Defining reprogramming checkpoints from singlecell. Epigenetics of induced pluripotency, the sevenheaded.
Evidence is emerging that epigenetic priming events early in the process may be critical. The teneleven translocation tet enzymes can catalyze the oxidation of 5methylcytosine 5mc to 5hydroxymethylcytosine 5hmc and further oxidized derivatives. Retinol and ascorbate drive erasure of epigenetic memory. Reprogramming to induced pluripotent stem cells ipscs proceeds in a stepwise manner with reprogramming factor binding, transcription, and chromatin states. Chromatin and its regulators are important controllers of reprogramming, and. Epigenetics of reprogramming to induced pluripotency. Somatic reprogramming involves global epigenetic remodeling, so the process of induced pluripotency serves as an ideal model to study epigenetic remodeling chen and pei, 2016.
Reprogramming of somatic cells to induced pluripotent stem cells involves a dynamic rearrangement of the epigenetic landscape. Mechanisms of pluripotency and epigenetic reprogramming in. This is a pdf file of an unedited manuscript that has. Butyrate greatly enhances derivation of human induced. Epigenetic reprogramming by histone acetyltransferase hag1. For example, during the epigenetic reprogramming of cells, the promoter regions of pluripotency genes undergo demethylation following either scnt or induced pluripotency. Therefore, further investigations of epigenetic modifications associated with ipsc reprogramming are required in an attempt to improve their selfrenew capacity. This cell type from gonadal ridges and mesenteries, 57 days after fertilization, was able to form colonies of embryoid bodies resembling eg and pluripotent stem cells. Dec 15, 2009 epigenetic reprogramming provides valuable resources for customized pluripotent stem cells generation, which are thought to be important bases of future regenerative medicine. Retinol and ascorbate drive erasure of epigenetic memory and. Pdf epigenetic memory in induced pluripotent stem cells.
Epigenetic modifiers facilitate induction and pluripotency. The reprogramming process is extremely slow, with low efficiency 0. Reprogramming to induced pluripotent stem cells ipscs proceeds in a. Epigenetics of reprogramming to induced pluripotency ncbi nih. Bernstein1,2,3 the demonstration of induced pluripotency and direct lineage conversion has led to remarkable insights regarding the roles of transcription factors and chromatin regulators in mediating cell state transitions. Only the core factors, oct4 and sox2, are strictly required, whereas the other components may primarily enhance reprogramming efficiency and can be substituted by other genes such as nanog and lin28 2, 3, 9. Transcription factormediated epigenetic reprogramming.
Unique molecular events during reprogramming of human somatic. Epigenetics and applications in the regenerative medicine rev assoc med bras 2017. Oct 25, 2016 epigenetic memory, in particular dna methylation, is established during development in differentiating cells and must be erased to create naive induced pluripotent stem cells. Together, exogenous genes were not effectively silenced in most of pipscs induced by epigenetic factors, especially in kdm3aderived pipscs figure 1e. Epigenetic regulation of pluripotency and differentiation.
Feb 15, 2009 for example, during the epigenetic reprogramming of cells, the promoter regions of pluripotency genes undergo demethylation following either scnt or induced pluripotency. Induced pluripotency defines the process by which somatic cells are converted into induced pluripotent stem cells ipscs upon overexpression of a small set of. Generation strategy and epigenetic mystery behind reprogramming pengfeiji, 1 sasichamanupipatpong, 2 ninaxie, 2,3 andyujingli 2 institute of genetics and development biology, chinese academy of sciences, beijing, china. In particular, an understanding of these processes is essential to the reprogramming of cells for biomedical applications, i. These pluripotent cells were called induced pluripotent. Butyrate greatly enhances derivation of human induced pluripotent stem cells by promoting epigenetic remodeling and the expression of pluripotencyassociated genes prashant mali, a,b binkuan chou,a,c jonathan yen,a,b zhaohui ye,a,d,e jizhong zou,a,e sarah dowey,a,e robert a. Epigenetic restructuring during reprogramming although induced pluripotency is dependent on exogenously introduced transcription factors, the epigenetic changes that take place during reprogramming are the. Unique molecular events during reprogramming of human. This experiment involved culturing these cells on a feeder layer, in the presence of leukemia inhibitory. Jan 30, 2018 the human inducible reprogramming system recently developed by cacchiarelli and colleagues cacchiarelli et al. Pluripotent cells have highly plastic genomes that display open chromatin that is abundantly marked by active histone modifications, making it poised for differentiation cues. Transcriptional and epigenetic mechanisms of cellular.
Pdf somatic cell nuclear transfer and transcriptionfactorbased reprogramming revert adult cells to an embryonic state, and yield pluripotent stem. Some somatic cells show demethylation of pluripotency genes e. In vitro reprogramming of mouse and human somatic cells to an embryonic state,discovery of mechanisms that control epigenetic states in human reprogramming and pluripotent. Molecular control of induced pluripotency thorold w. Induced pluripotent stem cells ipscs international federation of. The functions of micrornas in pluripotency and reprogramming. More recent studies have focused on identifying alternative approaches and factors that can be used to increase reprogramming efficiency of fibroblasts to pluripotency. Theunissen1 and rudolf jaenisch1,2, 1whitehead institute for biomedical research, massachusetts institute of technology, cambridge, ma 02142 usa 2department of biology, massachusetts institute of technology, cambridge, ma 02142 usa abstract deciphering the mechanisms of epigenetic reprogramming provides fundamental insights into cell. Current challenges in the therapeutic use of induced pluripotent stem cells ipscs in cancer therapy pravin potdar and shahid chaudhary abstract induced pluripotent stem cells ipscs technology has catapulted the field of stemcell biology through ectopic expression of reprogramming factors. Induced pluripotency and epigenetic reprogramming ncbi. Generation of human induced pluripotent stem cells using. Stem cells and epigenetic reprogramming intechopen. Mar 14, 20 reprogramming to induced pluripotent stem cells ipscs proceeds in a stepwise manner with reprogramming factor binding, transcription, and chromatin states changing during transitions.
Xinactivation an important feature in determining the state of pluripotency is the reactivation of the inactive x chromosome in female cells. Induced pluripotency and epigenetic reprogramming request pdf. Miles from the netherlands cancer institute recently uncovered a novel epigenetic barrier to the efficient induction of pluripotent stem cell reprogramming. The functions of micrornas in pluripotency and reprogramming trevor r. Here, we discuss recent findings about the potential mechanisms of epigenetic reprogramming, particularly genomewide dna demethylation, in preimplantation mouse embryos and pgcs. Evidence is emerging that epigenetic priming events early in the process may be critical for pluripotency induction later. We focus on dna methylation, dna demethylation, and common histone tail modifications. Therefore, we increased the efficiency with a novel combination of epigenetic and signaling molecules and profiled the transcriptomes of individual reprogramming cells. Epigenetic modifiers facilitate induction and pluripotency of. Induced pluripotency and oncogenic transformation are. An epigenomic roadmap to induced pluripotency reveals dna. Reprogramming somatic cells to induced pluripotent stem cells ipscs is accompanied by dramatic changes in epigenetic programs, including silencing of endogenous and exogenous retroviruses. It has become evident that faithful reprogramming is very dependent on various technological parameters. The molecular machinery underlying this process remains poorly defined.
Apr 14, 2010 it would be of great interest to test whether butyrate could reduce epigenetic barriers and enhance other types of epigenetic reprogramming such as transdifferentiation. What genes are required for successful reprogramming. Mar 15, 2010 induction of pluripotency from somatic cells by exogenous transcription factors is made possible by a variety of epigenetic changes that take place during the reprogramming process. Thus, while epigenetic factors can enhance reprogramming and activation of naive pluripotency genes in pipscs, their effects on silencing exogenous genes are variable. Deciphering the mechanisms of epigenetic reprogramming provides fundamental insights into cell fate decisions, which in turn reveal strategies to make the reprogramming process increasingly efficient. Embryonic stem cells and induced pluripotent stem cells ipscs exhibit similar and unique epigenetic features that endow them with pluripotency. Santos m 2011 open chromatin in pluripotency and reprogramming. The past several years have seen concerted efforts to elucidate the mechanisms of reprogramming, coalescing around several major questions. Epigenetic memory in induced pluripotent stem cells nature. Jan 26, 2019 elucidating the mechanism of reprogramming is confounded by heterogeneity due to the low efficiency and differential kinetics of obtaining induced pluripotent stem cells ipscs from somatic cells. Epigenetic as well as singlecell transcriptomic analyses on isolated reprogramming intermediates en route to induced pluripotency have generated invaluable mechanistic insights into the process of cell fate specification and transition. In fact, several researchers were able to reprogram somatic cells postmitotic into ipsc. Summary we report here that butyrate greatly enhances the efficiency of induced pluripotent stem ips cell derivation from human adult or fetal fibroblasts.
Current challenges in the therapeutic use of induced. Epigenetic reprogramming and induced pluripotency development. Reprogramming to induced pluripotent stem cells ipscs proceeds in a stepwise manner with reprogramming factor binding, transcription, and chromatin states changing during transitions. Dna demethylation 12 wk promoter demethylation of pluripotency genes e. Induced pluripotent stem cells ipscs are reprogrammed into the pluripotent state by the introduction of exogenous factors.