scholarly journals Neurogenin3 triggers beta-cell differentiation of retinoic acid-derived endoderm cells

2003 ◽  
Vol 371 (3) ◽  
pp. 831-841 ◽  
Author(s):  
Amedeo VETERE ◽  
Eleonora MARSICH ◽  
Matteo DI PIAZZA ◽  
Raffaella KONCAN ◽  
Fulvio MICALI ◽  
...  

Neurogenin3 is a member of the basic helix-loop-helix ('bHLH') family of transcription factors. It plays a crucial role in the commitment of embryonic endoderm into the pancreatic differentiation programme. This factor is considered to act upstream of a cascade of other transcription factors, leading to the fully differentiated endocrine phenotype. Direct observation of the sequential activation of these factors starting from Neurogenin3 had never been demonstrated. By using retinoic acid-derived-endoderm F9 cells as a model, the present study indicates that the ectopic expression of Neurogenin3 is able to start the differentiation pathway of endocrine pancreas. Neurogenin3 triggers the expression of several pancreatic transcription factors following a well defined temporal activation sequence. By reverse transcriptase PCR, immunohistochemistry and RIA, it is shown that stable transfected cells are able to form embryod bodies that produce insulin in response to glucose stimulation. This is the first report of a differentiation event induced by the ectopic expression of a transcription factor in embryonic pluripotent stem cells.

Author(s):  
Kee-Pyo Kim ◽  
Dong Wook Han ◽  
Johnny Kim ◽  
Hans R. Schöler

AbstractEctopic expression of Oct4, Sox2, Klf4 and c-Myc can reprogram somatic cells into induced pluripotent stem cells (iPSCs). Attempts to identify genes or chemicals that can functionally replace each of these four reprogramming factors have revealed that exogenous Oct4 is not necessary for reprogramming under certain conditions or in the presence of alternative factors that can regulate endogenous Oct4 expression. For example, polycistronic expression of Sox2, Klf4 and c-Myc can elicit reprogramming by activating endogenous Oct4 expression indirectly. Experiments in which the reprogramming competence of all other Oct family members tested and also in different species have led to the decisive conclusion that Oct proteins display different reprogramming competences and species-dependent reprogramming activity despite their profound sequence conservation. We discuss the roles of the structural components of Oct proteins in reprogramming and how donor cell epigenomes endow Oct proteins with different reprogramming competences.


2020 ◽  
Vol 5 (1) ◽  
pp. 1-4 ◽  
Author(s):  
David Septian Sumanto Marpaung ◽  
Ayu Oshin Yap Sinaga

The four transcription factors OCT4, SOX2, KLF4 and c-MYC are highly expressed in embryonic stem cells (ESC) and their overexpression can induce pluripotency, the ability to differentiate into all cell types of an organism. The ectopic expression such transcription factors could reprogram somatic stem cells become induced pluripotency stem cells (iPSC), an embryonic stem cells-like. Production of recombinant pluripotency factors gain interests due to high demand from generation of induced pluripotent stem cells in regenerative medical therapy recently. This review will focus on demonstrate the recent advances in recombinant pluripotency factor production using various host.


2020 ◽  
Author(s):  
Cheen Euong Ang ◽  
Victor Hipolito Olmos ◽  
Bo Zhou ◽  
Qian Yi Lee ◽  
Rahul Sinha ◽  
...  

SUMMARYGeneration of neurons of vast diversity involves early spatial and temporal patterning of the neuronal precursors by morphogenic gradients and combinatorial expression of transcription factors. While the proneuronal function of the basic-helix-loop-helix (bHLH) transcription factor Ngn2 is well established, its role in neuronal subtype specification remains unclear. Here, we found that coexpressing NGN2 with the forebrain homeobox factor EMX1 converts human pluripotent stem cells into a highly homogeneous glutamatergic forebrain neurons without partial cholinergic and monoaminergic gene programs observed in cells infected with NGN2 only. Our molecular characterization revealed that transcriptional output and genomic targeting of Ngn2 is altered by co-factors such as EMX1 explaining the more focused subtype specification. Ngn2 function is less modified by the chromatin environment and does not affect regionalization of pre-patterned neural progenitors. These results enable improved strategies for generating a plethora of defined neuronal subpopulations from pluripotent stem cells for therapeutic or disease-modeling purposes.HighlightsNGN2 converts human ES cells into glutamatergic neurons some of which co-express a partial cholinergic programNGN2 directly binds to and activates ISL1 in ES cells which together with PHOX2A/B induce cholinergic genesAnterior-posterior regionalization affects NGN2 binding and transcriptional output but does not focus subtype specificationForebrain homeobox factors including EMX1 and FOXG1 redirect NGN2 chromatin binding and repress posterior and cholinergic genes, resulting in homogeneous forebrain excitatory neurons


2011 ◽  
Vol 23 (1) ◽  
pp. 249
Author(s):  
D. Kumar ◽  
D. Malakar ◽  
R. Dutta ◽  
S. Garg ◽  
S. Sahu ◽  
...  

Embryonic stem cells (ESC) are derived from the inner cell mass of blastocysts and proliferate extensively while maintaining pluripotency. They can be used for the treatment of juvenile diabetes, Parkinson’s disease, heart failure, and spinal cord injury. However, the use of embryos and tissue rejection remain concerns for ESC transplantation. Reprogramming of somatic cells may be done by different methods such as somatic cell nuclear transfer (Wilmut et al. 1997), fusion of somatic cells (Cowen et al. 2005), treatment with the extract of the pluripotent stem cells (Johnson Rajasingh 2008), and by the stable ectopic expression of defined factors in the somatic cells (Takahashi and Yamanaka 2006). Several transcription factors, including Oct3/4 (Nichols et al. 1998; Niwa et al. 2000), Sox2 (Avilion et al. 2003), and Nanog (Chambers et al. 2003; Mitsui et al. 2003), function in the maintenance of pluripotency in both early embryos and ESC. Takahashi and Yamanaka reported reprogramming the fibroblast cells into stem cells by introducing Oct3/4, Sox2, c-Myc, and Klf4 in mouse embryonic and adult fibroblasts. Yu et al. (2007) demonstrated that four transcription factors (OCT-4, SOX2, NANOG, and LIN28) are sufficient to reprogramme human somatic cells to pluripotent stem cells that exhibit the essential characteristics of ESC. Nakagawa et al. (2008) used three factors (OCT3/4, SOX2, and KLF4) for human iPS cell production from somatic cells. We are trying to reprogramme the adult goat fibroblast cells in induced pluripotent stem cells by using ectopic expression of transcription factors such as Oct-4, Sox2, Nanog, and Lin28. We collected the ovaries from a slaughtered animal from Delhi and collected the oocytes from ovaries. Then after the collection, A and B grade oocytes were selected. Selected oocytes were processed and incubated in in vitro maturation media for 24 h. We collected semen from a male goat, and it was processed and capacitated in sperm TALP. Capacitated sperms were used for IVF of the in vitro matured oocytes in ferTALP. After 12 h sperm were washed from oocytes in embryo developing media (EDM), and oocytes were cultured (in vitro) in EDM. After 24 h cleavage occurred. The cleaved embryos were cultured for 6 to 7 days. At the 7th day, we got blastocysts. From these blastocysts, inner cell mass was isolated enzymatically and cultured to get ESC. The ESC were cultured for 7 passages and used for RNA isolation. The RNA was isolated from these stem cells by the Trizol method. Complementary DNA was prepared by RT-PCR. Using gene-specific primer for Oct-4, Nanog, and Sox2, DNA was amplified. The DNA for the Oct-4, Nanog, and Sox2 genes was cloned in pJET cloning vector and transformed in Top10 E. coli competence cells. After screening, plasmid was isolated and sent for sequencing. Sequences were analysed and the complete open reading frame was created for Oct-4, Nanog, and Sox2.


1997 ◽  
Vol 17 (3) ◽  
pp. 1552-1561 ◽  
Author(s):  
E J Schwarz ◽  
M J Reginato ◽  
D Shao ◽  
S L Krakow ◽  
M A Lazar

Adipocyte differentiation is thought to involve sequential induction of the transcription factors C/EBPbeta, peroxisome proliferator-activated receptor gamma (PPARgamma), and C/EBPalpha. C/EBPalpha expression is both necessary and sufficient for adipocyte differentiation. Here we report that ectopic expression of either C/EBPalpha or C/EBPbeta induces PPARgamma expression and adipogenesis and that retinoic acid (RA) completely inhibits adipogenesis by either form of C/EBP. In studies of normal preadipocytes, RA does not prevent C/EBPbeta induction but blocks induction of PPARgamma, C/EBPalpha, and adipogenesis. In transient transfection studies, liganded RA receptor (RAR) specifically blocks transcriptional activation by either C/EBPalpha or C/EBPbeta. These results strongly suggest that C/EBPalpha substitutes for C/EBPbeta to induce adipocyte differentiation and that liganded RAR inhibits adipogenesis by blocking C/EBPbeta-mediated induction of downstream genes.


2017 ◽  
Author(s):  
Adekunle Ebenezer Omole ◽  
Adegbenro Omotuyi John Fakoya

The discovery of induced pluripotent stem cells (iPSCs) by Shinya Yamanaka in 2006 was heralded as a major breakthrough of the decade in stem cell research. The ability to reprogrammed human somatic cells to a pluripotent embryonic stem cell-like state through the ectopic expression of a combination of embryonic transcription factors was greeted with great excitement by scientists and bioethicists. The reprogramming technology offers the opportunity to generate patient-specific stem cells for modeling human diseases, drug development and screening, and individualized regenerative cell therapy. However, fundamental questions have been raised regarding the molecular mechanism of iPSCs generation, a process still poorly understood by scientists. The efficiency of reprogramming of iPSCs remains low due to the effect of various barriers of reprogramming. There is also the risk of chromosomal instability and oncogenic transformation associated with the use of viral vectors, such as retrovirus and lentivirus, which deliver the reprogramming transcription factors by integration in the host cell genome. These challenges can hinder the therapeutic prospects and promise of iPSCs and their clinical applications. Consequently, extensive studies have been done to elucidate the molecular mechanism of reprogramming and novel strategies have been identified which help to improve the efficiency of reprogramming methods and overcome the safety concerns linked with iPSCs generation. Distinct barriers and enhancers of reprogramming have been elucidated and non-integrating reprogramming methods have been reported. Here, we summarize the progress and the recent advances that have been made over the last 10 years in the iPSCs field, with emphasis on the molecular mechanism of reprogramming, strategies to improve the efficiency of reprogramming, characteristics and limitations of iPSCs, and the progress made in the applications of iPSCs in the field of disease modelling, drug discovery and regenerative medicine. Additionally, this study appraised the role of genomic editing technology in the generation of healthy iPSCs.


2017 ◽  
Author(s):  
Adekunle Ebenezer Omole ◽  
Adegbenro Omotuyi John Fakoya

The discovery of induced pluripotent stem cells (iPSCs) by Shinya Yamanaka in 2006 was heralded as a major breakthrough of the decade in stem cell research. The ability to reprogrammed human somatic cells to a pluripotent embryonic stem cell-like state through the ectopic expression of a combination of embryonic transcription factors was greeted with great excitement by scientists and bioethicists. The reprogramming technology offers the opportunity to generate patient-specific stem cells for modeling human diseases, drug development and screening, and individualized regenerative cell therapy. However, fundamental questions have been raised regarding the molecular mechanism of iPSCs generation, a process still poorly understood by scientists. The efficiency of reprogramming of iPSCs remains low due to the effect of various barriers of reprogramming. There is also the risk of chromosomal instability and oncogenic transformation associated with the use of viral vectors, such as retrovirus and lentivirus, which deliver the reprogramming transcription factors by integration in the host cell genome. These challenges can hinder the therapeutic prospects and promise of iPSCs and their clinical applications. Consequently, extensive studies have been done to elucidate the molecular mechanism of reprogramming and novel strategies have been identified which help to improve the efficiency of reprogramming methods and overcome the safety concerns linked with iPSCs generation. Distinct barriers and enhancers of reprogramming have been elucidated and non-integrating reprogramming methods have been reported. Here, we summarize the progress and the recent advances that have been made over the last 10 years in the iPSCs field, with emphasis on the molecular mechanism of reprogramming, strategies to improve the efficiency of reprogramming, characteristics and limitations of iPSCs, and the progress made in the applications of iPSCs in the field of disease modelling, drug discovery and regenerative medicine. Additionally, this study appraised the role of genomic editing technology in the generation of healthy iPSCs.


2016 ◽  
Vol 28 (2) ◽  
pp. 242
Author(s):  
K.-H. Choi ◽  
D. Son ◽  
D.-K. Lee ◽  
J.-N. Oh ◽  
S.-H. Kim ◽  
...  

Cellular reprogramming of committed cells into a pluripotent state can be accomplished by ectopic expression of genes such as OCT4, SOX2, KLF4, and MYC. However, during reprogramming, it has been verified that failures of reactivating endogenous genes and epigenetic remodelling lead to partially reprogrammed cells exhibiting features similar to those of fully reprogrammed cells. In this study, partially reprogrammed induced pluripotent stem cells (pre-iPSC) were derived from porcine fetal fibroblasts via drug-inducible vector carrying human transcription factors (OCT4, SOX2, KLF4, and MYC). Therefore, this study aimed to investigate characteristics of pre-iPSC and reprogramming mechanisms. The pre-iPSC were stably maintained over an extended period having in vitro differentiation ability into 3 germ layers. The pluripotent state of pre-iPSC was regulated by modulation of culture condition. They showed naive- or primed-like pluripotent state in leukemia inhibitory factor (LIF) or basic fibroblast growth factor (bFGF) supplemented culture conditions respectively. However, pre-iPSC could not be maintained without ectopic expression of transgenes. The cultured pre-iPSC expressed endogenous transcription factors (OCT4 and SOX2) except for NANOG known as gateway into complete reprogramming. In addition, endogenous genes related to mesenchymal-to-epithelial transition (DPPA2, CDH1, EPCAM, and OCLN) were not sufficiently reactivated as measured by qPCR. DNA methylation analysis for promoters of OCT4, NANOG, and XIST showed that epigenetic reprogramming did not occurred in female pre-iPSC. Given the results, we found that expression of exogenous genes could not sufficiently activate the essential endogenous genes and remodel the epigenetic milieu for achieving faithful pluripotency in pig. Accordingly, investigating pre-iPSC could help us to improve and develop reprogramming methods via understanding reprogramming mechanisms in pig. This work was supported by the Next-generation BioGreen 21 Program (PJ0113002015), Rural Development Administration, Republic of Korea.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4370 ◽  
Author(s):  
Adekunle Ebenezer Omole ◽  
Adegbenro Omotuyi John Fakoya

The discovery of induced pluripotent stem cells (iPSCs) by Shinya Yamanaka in 2006 was heralded as a major breakthrough of the decade in stem cell research. The ability to reprogram human somatic cells to a pluripotent embryonic stem cell-like state through the ectopic expression of a combination of embryonic transcription factors was greeted with great excitement by scientists and bioethicists. The reprogramming technology offers the opportunity to generate patient-specific stem cells for modeling human diseases, drug development and screening, and individualized regenerative cell therapy. However, fundamental questions have been raised regarding the molecular mechanism of iPSCs generation, a process still poorly understood by scientists. The efficiency of reprogramming of iPSCs remains low due to the effect of various barriers to reprogramming. There is also the risk of chromosomal instability and oncogenic transformation associated with the use of viral vectors, such as retrovirus and lentivirus, which deliver the reprogramming transcription factors by integration in the host cell genome. These challenges can hinder the therapeutic prospects and promise of iPSCs and their clinical applications. Consequently, extensive studies have been done to elucidate the molecular mechanism of reprogramming and novel strategies have been identified which help to improve the efficiency of reprogramming methods and overcome the safety concerns linked with iPSC generation. Distinct barriers and enhancers of reprogramming have been elucidated, and non-integrating reprogramming methods have been reported. Here, we summarize the progress and the recent advances that have been made over the last 10 years in the iPSC field, with emphasis on the molecular mechanism of reprogramming, strategies to improve the efficiency of reprogramming, characteristics and limitations of iPSCs, and the progress made in the applications of iPSCs in the field of disease modelling, drug discovery and regenerative medicine. Additionally, this study appraises the role of genomic editing technology in the generation of healthy iPSCs.


Sign in / Sign up

Export Citation Format

Share Document