Porcine iPSC Generation: Testing Different Protocols to a Successful Application

2021 ◽  
Author(s):  
Oriol Iborra-Egea ◽  
Daina Martínez-Falguera ◽  
Santiago Roura ◽  
Antoni Bayes-Genis ◽  
Ángel Raya ◽  
...  
Keyword(s):  
2018 ◽  
Author(s):  
Jason Lee ◽  
Miguel Ochoa ◽  
Pablo Maceda ◽  
Eun Yoon ◽  
Lara Samarneh ◽  
...  

Transgenic methods for direct reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) are effective in cell culture systems but ultimately limit the utility of iPSCs due to concerns of mutagenesis and tumor formation. Recent studies have suggested that some transgenes can be eliminated by using small molecules as an alternative to transgenic methods of iPSC generation. We developed a high throughput platform for applying complex dynamic mechanical forces to cultured cells. Using this system, we screened for optimized conditions to stimulate the activation of Oct-4 and other transcription factors to prime the development of pluripotency in mouse fibroblasts. Using high throughput mechanobiological screening assays, we identified small molecules that can synergistically enhance the priming of pluripotency of mouse fibroblasts in combination with mechanical loading. Taken together, our findings demonstrate the ability of mechanical forces to induce reprograming factors and support that biophysical conditioning can act cooperatively with small molecules to priming the induction pluripotency in somatic cells.


2019 ◽  
Vol 16 (1) ◽  
pp. 56-81 ◽  
Author(s):  
Krishna Kumar Haridhasapavalan ◽  
Khyati Raina ◽  
Chandrima Dey ◽  
Poulomi Adhikari ◽  
Rajkumar P. Thummer
Keyword(s):  

2013 ◽  
Vol 13 (4) ◽  
pp. 379-381 ◽  
Author(s):  
Justin Brumbaugh ◽  
Konrad Hochedlinger
Keyword(s):  

2016 ◽  
Vol 365 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Jitrada Phetfong ◽  
Aungkura Supokawej ◽  
Methichit Wattanapanitch ◽  
Pakpoom Kheolamai ◽  
Yaowalak U-pratya ◽  
...  
Keyword(s):  

2016 ◽  
Vol 113 (46) ◽  
pp. 13057-13062 ◽  
Author(s):  
Yohei Hayashi ◽  
Edward C. Hsiao ◽  
Salma Sami ◽  
Mariselle Lancero ◽  
Christopher R. Schlieve ◽  
...  

Fibrodysplasia ossificans progressiva (FOP) patients carry a missense mutation in ACVR1 [617G > A (R206H)] that leads to hyperactivation of BMP-SMAD signaling. Contrary to a previous study, here we show that FOP fibroblasts showed an increased efficiency of induced pluripotent stem cell (iPSC) generation. This positive effect was attenuated by inhibitors of BMP-SMAD signaling (Dorsomorphin or LDN1931890) or transducing inhibitory SMADs (SMAD6 or SMAD7). In normal fibroblasts, the efficiency of iPSC generation was enhanced by transducing mutant ACVR1 (617G > A) or SMAD1 or adding BMP4 protein at early times during the reprogramming. In contrast, adding BMP4 at later times decreased iPSC generation. ID genes, transcriptional targets of BMP-SMAD signaling, were critical for iPSC generation. The BMP-SMAD-ID signaling axis suppressed p16/INK4A-mediated cell senescence, a major barrier to reprogramming. These results using patient cells carrying the ACVR1 R206H mutation reveal how cellular signaling and gene expression change during the reprogramming processes.


2021 ◽  
Author(s):  
Chiaki Akifuji ◽  
Mio Iwasaki ◽  
Yuka Kawahara ◽  
Chiho Sakurai ◽  
Yusheng Cheng ◽  
...  

Abstract Induced pluripotent stem cells (iPSCs) have the potential to differentiate into any cell in the body and thus have attractive regenerative medicine potential. Current iPSC generation protocols, however, have low efficiency and show variable quality among clones. This variability influences the efficiency and reproducibility of iPSC differentiation. Our previous study reported that MYC proteins (c-MYC and MYCL) are important for the reprogramming efficiency and germline transmission of iPSCs, but that MYCL can generate iPSC colonies more efficiently than c-MYC. However, why c-MYC and MYCL cause different reprogramming efficiencies is unknown. In this study, we found that MYC Box 0 (MB0) and MB2, two functional domains conserved in the MYC protein family, contribute to the phenotypic difference and promote iPSC generation in MYCL-induced reprogramming. Proteome analysis suggested that in MYCL-induced reprogramming, cell adhesion-related cytoskeletal proteins are regulated by the MB0 domain, while RNA processes are regulated by the MB2 domain. These findings provide a molecular explanation for why MYCL has higher reprogramming efficiency than c-MYC.


2019 ◽  
Author(s):  
Coral K. Wille ◽  
Rupa Sridharan

ABSTRACTThe ability of pluripotent stem cells to be poised to differentiate into any somatic cell type is partly derived from a unique chromatin structure that is depleted for transcriptional elongation associated epigenetic modifications, primarily H3K79 methylation. Inhibiting the H3K79 methyltransferase, Dot1L, increases the efficiency of reprogramming somatic cells to induced pluripotent stem cells (iPSCs) most potently at the mid-point of the process. Surprisingly, despite the enrichment of H3K79me2 on thousands of actively transcribed genes, Dot1L inhibition (Dot1Li) results in few changes in steady state mRNA levels during reprogramming. Dot1Li spuriously upregulates genes not involved in pluripotency and does not shutdown the somatic program. Depletion of the few genes that are downregulated, such as Nfix, enhances reprogramming efficiency in cooperation with Dot1Li. Contrary to the prevalent view, Dot1Li promotes iPSC generation beyond early phases of reprogramming such as the mesenchymal to epithelial transition and from already epithelial cell types including keratinocytes. Significantly, Dot1L inhibition does not enhance lineage conversion to neurons or muscle cells. Taken together, our results indicate that H3K79me is not a universal barrier of cell fate transitions but specifically protects somatic cells from reverting to the pluripotent state.


2018 ◽  
Author(s):  
Jindun Zhang ◽  
Xuefei Gao ◽  
Jian Yang ◽  
Xiaoying Fan ◽  
Wei Wang ◽  
...  

SummaryXist is the master regulator of X chromosome inactivation (XCI). In order to further understand the Xist locus in reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) and in somatic cell nuclear transfer (SCNT), we tested transcription-factor-like effectors (TALE)-based designer transcriptional factors (dTFs), which were specific to numerous regions at the Xist locus. We report that the selected dTF repressor 6 (R6) binding the intron 1 of Xist, which did not affect Xist expression in mouse embryonic fibroblasts (MEFs), substantially improved the iPSC generation and the SCNT preimplantation embryo development. Conversely, the dTF activator targeting the same genomic region of R6 decreased iPSC formation, and blocked SCNT-embryo development. These results thus uncover the critical requirement for the Xist locus in epigenetic resetting, which is not directly related to Xist transcription. This may provide a unique route to improving the reprogramming.


2020 ◽  
Author(s):  
Coral K. Wille ◽  
Edwin N. Neumann ◽  
Aniruddha J. Deshpande ◽  
Rupa Sridharan

ABSTRACTHistone-modifying enzymes function as part of protein complexes that alter the accessibility of chromatin to elicit differential gene expression patterns. Dot1L, the sole histone H3 lysine (K) 79 (H3K79) methyltransferase, is associated with proteins that recognize specific histone modifications and target Dot1L to particular chromatin contexts. Here we find that depletion of the Dot1L interacting protein AF10, which recognizes unmodified H3K27, mimics Dot1L catalytic inhibition to increase the efficiency of reprogramming somatic cells to induced pluripotent stem cells (iPSCs). AF10 deletion results in almost no steady state transcriptional changes yet is responsible for half of the Dot1L iPSC reprogramming phenotype. In contrast, reduced levels of Dot1L interactors AF9 and ENL that recognize H3 acetylation decrease iPSC generation. Despite the opposite effects in reprogramming of Dot1L interacting proteins with differing histone reader specificity, we find that the AF10-histone interaction domain is dispensable for increased iPSC generation. Instead, the AF10-Dot1L interaction domain that potentiates H3K79 di- and tri-methylation is a barrier to pluripotency acquisition. Taken together we reveal a key role for higher order gene body histone methylation in safeguarding cell identity.


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