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  1. Reprogramming mouse fibroblasts into engraftable myeloerythroid and lymphoid progenitors

    PubMed Central

    Cheng, Hui; Ang, Heather Yin-Kuan; A. EL Farran, Chadi; Li, Pin; Fang, Hai Tong; Liu, Tong Ming; Kong, Say Li; Chin, Michael Lingzi; Ling, Wei Yin; Lim, Edwin Kok Hao; Li, Hu; Huber, Tara; Loh, Kyle M.; Loh, Yuin-Han; Lim, Bing

    2016-01-01

    Recent efforts have attempted to convert non-blood cells into hematopoietic stem cells (HSCs) with the goal of generating blood lineages de novo. Here we show that hematopoietic transcription factors Scl, Lmo2, Runx1 and Bmi1 can convert a developmentally distant lineage (fibroblasts) into ‘induced hematopoietic progenitors' (iHPs). Functionally, iHPs generate acetylcholinesterase+ megakaryocytes and phagocytic myeloid cells in vitro and can also engraft immunodeficient mice, generating myeloerythoid and B-lymphoid cells for up to 4 months in vivo. Molecularly, iHPs transcriptionally resemble native Kit+ hematopoietic progenitors. Mechanistically, reprogramming factor Lmo2 implements a hematopoietic programme in fibroblasts by rapidly binding to and upregulating the Hhex and Gfi1 genes within days. Moreover the reprogramming transcription factors also require extracellular BMP and MEK signalling to cooperatively effectuate reprogramming. Thus, the transcription factors that orchestrate embryonic hematopoiesis can artificially reconstitute this programme in developmentally distant fibroblasts, converting them into engraftable blood progenitors. PMID:27869129

  2. Gaining myocytes or losing fibroblasts: Challenges in cardiac fibroblast reprogramming for infarct repair.

    PubMed

    Nagalingam, Raghu S; Safi, Hamza A; Czubryt, Michael P

    2016-04-01

    Unlike most somatic tissues, the heart possesses a very limited inherent ability to repair itself following damage. Attempts to therapeutically salvage the myocardium after infarction, either by sparing surviving myocytes or by injection of exogenous cells of varied provenance, have met with limited success. Cardiac fibroblasts are numerous, resistant to hypoxia, and amenable to phenotype reprogramming to cardiomyocytes - a potential panacea to an intractable problem. However, the long-term effects of mass conversion of fibroblasts are as-yet unknown. Since fibroblasts play key roles in normal cardiac function, treating these cells as a ready source of replacements for myocytes may have the effect of swapping one problem for another. This review briefly examines the roles of cardiac fibroblasts, recaps the strides made so far in their reprogramming to cardiomyocytes both in vitro and in vivo, and discusses the potential ramifications of large-scale cellular identity swapping. While such therapy offers great promise, the potential repercussions require consideration and careful study.

  3. Direct reprogramming of human fibroblasts to functional and expandable hepatocytes.

    PubMed

    Huang, Pengyu; Zhang, Ludi; Gao, Yimeng; He, Zhiying; Yao, Dan; Wu, Zhitao; Cen, Jin; Chen, Xiaotao; Liu, Changcheng; Hu, Yiping; Lai, Dongmei; Hu, Zhenlei; Chen, Li; Zhang, Ying; Cheng, Xin; Ma, Xiaojun; Pan, Guoyu; Wang, Xin; Hui, Lijian

    2014-03-06

    The generation of large numbers of functional human hepatocytes for cell-based approaches to liver disease is an important and unmet goal. Direct reprogramming of fibroblasts to hepatic lineages could offer a solution to this problem but so far has only been achieved with mouse cells. Here, we generated human induced hepatocytes (hiHeps) from fibroblasts by lentiviral expression of FOXA3, HNF1A, and HNF4A. hiHeps express hepatic gene programs, can be expanded in vitro, and display functions characteristic of mature hepatocytes, including cytochrome P450 enzyme activity and biliary drug clearance. Upon transplantation into mice with concanavalin-A-induced acute liver failure and fatal metabolic liver disease due to fumarylacetoacetate dehydrolase (Fah) deficiency, hiHeps restore the liver function and prolong survival. Collectively, our results demonstrate successful lineage conversion of nonhepatic human cells into mature hepatocytes with potential for biomedical and pharmaceutical applications.

  4. Hypoxia Enhances Direct Reprogramming of Mouse Fibroblasts to Cardiomyocyte-Like Cells.

    PubMed

    Wang, Yanyan; Shi, Shujun; Liu, Huiwen; Meng, Li

    2016-02-01

    Recent work has shown that mouse and human fibroblasts can be reprogrammed to cardiomyocyte-like cells with a combination of transcription factors. Current research has focused on improving the efficiency and mechanisms for fibroblast reprogramming. Previously, it has been reported that hypoxia enhances fibroblast cell reprogramming to pluripotent stem cells. In this study, we observed that 6 h of hypoxic conditions (2% oxygen) on newborn mouse dermal fibroblasts can improve the efficiency of reprogramming to cardiomyocyte-like cells. Expression of cardiac-related genes and proteins increased at 4 weeks after transfer of three transcription factors (Gata4/Mef2c/Tbx5 [GMT]). However, beating cardiomyocyte cells were not detected. The epigenetic mechanism of hypoxia-induced fibroblast reprogramming to cardiomyocyte cells requires further study.

  5. BMPs functionally replace Klf4 and support efficient reprogramming of mouse fibroblasts by Oct4 alone

    PubMed Central

    Chen, Jiekai; Liu, Jing; Yang, Jiaqi; Chen, You; Chen, Jing; Ni, Su; Song, Hong; Zeng, Lingwen; Ding, Ke; Pei, Duanqing

    2011-01-01

    Generation of induced pluripotent stem cells by defined factors has become a useful model to investigate the mechanism of reprogramming and cell fate determination. However, the precise mechanism of factor-based reprogramming remains unclear. Here, we show that Klf4 mainly acts at the initial phase of reprogramming to initiate mesenchymal-to-epithelial transition and can be functionally replaced by bone morphogenetic proteins (BMPs). BMPs boosted the efficiency of Oct4/Sox2-mediated reprogramming of mouse embryonic fibroblasts (MEFs) to ∼1%. BMPs also promoted single-factor Oct4-based reprogramming of MEFs and tail tibial fibroblasts. Our studies clarify the contribution of Klf4 in reprogramming and establish Oct4 as a singular setter of pluripotency in differentiated cells. PMID:21135873

  6. MiR-133 promotes cardiac reprogramming by directly repressing Snai1 and silencing fibroblast signatures.

    PubMed

    Muraoka, Naoto; Yamakawa, Hiroyuki; Miyamoto, Kazutaka; Sadahiro, Taketaro; Umei, Tomohiko; Isomi, Mari; Nakashima, Hanae; Akiyama, Mizuha; Wada, Rie; Inagawa, Kohei; Nishiyama, Takahiko; Kaneda, Ruri; Fukuda, Toru; Takeda, Shu; Tohyama, Shugo; Hashimoto, Hisayuki; Kawamura, Yoshifumi; Goshima, Naoki; Aeba, Ryo; Yamagishi, Hiroyuki; Fukuda, Keiichi; Ieda, Masaki

    2014-07-17

    Fibroblasts can be directly reprogrammed into cardiomyocyte-like cells (iCMs) by overexpression of cardiac transcription factors or microRNAs. However, induction of functional cardiomyocytes is inefficient, and molecular mechanisms of direct reprogramming remain undefined. Here, we demonstrate that addition of miR-133a (miR-133) to Gata4, Mef2c, and Tbx5 (GMT) or GMT plus Mesp1 and Myocd improved cardiac reprogramming from mouse or human fibroblasts by directly repressing Snai1, a master regulator of epithelial-to-mesenchymal transition. MiR-133 overexpression with GMT generated sevenfold more beating iCMs from mouse embryonic fibroblasts and shortened the duration to induce beating cells from 30 to 10 days, compared to GMT alone. Snai1 knockdown suppressed fibroblast genes, upregulated cardiac gene expression, and induced more contracting iCMs with GMT transduction, recapitulating the effects of miR-133 overexpression. In contrast, overexpression of Snai1 in GMT/miR-133-transduced cells maintained fibroblast signatures and inhibited generation of beating iCMs. MiR-133-mediated Snai1 repression was also critical for cardiac reprogramming in adult mouse and human cardiac fibroblasts. Thus, silencing fibroblast signatures, mediated by miR-133/Snai1, is a key molecular roadblock during cardiac reprogramming.

  7. Reprogramming of COPD lung fibroblasts through formation of induced pluripotent stem cells

    PubMed Central

    Gunji, Yoko; Iwasawa, Shunichiro; Nelson, Amy; Farid, Maha; Ikari, Jun; Liu, Xiangde; Wang, Xingqi; Michalski, Joel; Smith, Lynette; Iqbal, Javeed; Behery, Radwa El; West, William; Yelamanchili, Sowmya; Rennard, Deborah; Holz, Olaf; Mueller, Kai-Christian; Magnussen, Helgo; Rabe, Klaus; Castaldi, Peter J; Rennard, Stephen I.

    2014-01-01

    Reprogramming somatic cells to induced pluripotent stem cells (iPSCs) eliminates many epigenetic modifications that characterize differentiated cells. In this study, we tested whether functional differences between chronic obstructive pulmonary disease (COPD) and non-COPD fibroblasts could be reduced utilizing this approach. Primary fibroblasts from non-COPD and COPD patients were reprogrammed to iPSCs. Reprogrammed iPSCs were positive for oct3/4, nanog, and sox2, formed embryoid bodies in vitro, and induced teratomas in nonobese diabetic/severe combined immunodeficient mice. Reprogrammed iPSCs were then differentiated into fibroblasts (non-COPD-i and COPD-i) and were assessed either functionally by chemotaxis and gel contraction or for gene expression by microarrays and compared with their corresponding primary fibroblasts. Primary COPD fibroblasts contracted three-dimensional collagen gels and migrated toward fibronectin less robustly than non-COPD fibroblasts. In contrast, redifferentiated fibroblasts from iPSCs derived from the non-COPD and COPD fibroblasts were similar in response in both functional assays. Microarray analysis identified 1,881 genes that were differentially expressed between primary COPD and non-COPD fibroblasts, with 605 genes differing by more than twofold. After redifferentiation, 112 genes were differentially expressed between COPD-i and non-COPD-i with only three genes by more than twofold. Similar findings were observed with microRNA (miRNA) expression: 56 miRNAs were differentially expressed between non-COPD and COPD primary cells; after redifferentiation, only 3 miRNAs were differentially expressed between non-COPD-i and COPD-i fibroblasts. Interestingly, of the 605 genes that were differentially expressed between COPD and non-COPD fibroblasts, 293 genes were changed toward control after redifferentiation. In conclusion, functional and epigenetic alterations of COPD fibroblasts can be reprogrammed through formation of iPSCs. PMID

  8. Akt1/protein kinase B enhances transcriptional reprogramming of fibroblasts to functional cardiomyocytes.

    PubMed

    Zhou, Huanyu; Dickson, Matthew E; Kim, Min Soo; Bassel-Duby, Rhonda; Olson, Eric N

    2015-09-22

    Conversion of fibroblasts to functional cardiomyocytes represents a potential approach for restoring cardiac function after myocardial injury, but the technique thus far has been slow and inefficient. To improve the efficiency of reprogramming fibroblasts to cardiac-like myocytes (iCMs) by cardiac transcription factors [Gata4, Hand2, Mef2c, and Tbx5 (GHMT)], we screened 192 protein kinases and discovered that Akt/protein kinase B dramatically accelerates and amplifies this process in three different types of fibroblasts (mouse embryo, adult cardiac, and tail tip). Approximately 50% of reprogrammed mouse embryo fibroblasts displayed spontaneous beating after 3 wk of induction by Akt plus GHMT. Furthermore, addition of Akt1 to GHMT evoked a more mature cardiac phenotype for iCMs, as seen by enhanced polynucleation, cellular hypertrophy, gene expression, and metabolic reprogramming. Insulin-like growth factor 1 (IGF1) and phosphoinositol 3-kinase (PI3K) acted upstream of Akt whereas the mitochondrial target of rapamycin complex 1 (mTORC1) and forkhead box o3 (Foxo3a) acted downstream of Akt to influence fibroblast-to-cardiomyocyte reprogramming. These findings provide insights into the molecular basis of cardiac reprogramming and represent an important step toward further application of this technique.

  9. Dissecting direct reprogramming from fibroblast to neuron using single-cell RNA-seq.

    PubMed

    Treutlein, Barbara; Lee, Qian Yi; Camp, J Gray; Mall, Moritz; Koh, Winston; Shariati, Seyed Ali Mohammad; Sim, Sopheak; Neff, Norma F; Skotheim, Jan M; Wernig, Marius; Quake, Stephen R

    2016-06-16

    Direct lineage reprogramming represents a remarkable conversion of cellular and transcriptome states. However, the intermediate stages through which individual cells progress during reprogramming are largely undefined. Here we use single-cell RNA sequencing at multiple time points to dissect direct reprogramming from mouse embryonic fibroblasts to induced neuronal cells. By deconstructing heterogeneity at each time point and ordering cells by transcriptome similarity, we find that the molecular reprogramming path is remarkably continuous. Overexpression of the proneural pioneer factor Ascl1 results in a well-defined initialization, causing cells to exit the cell cycle and re-focus gene expression through distinct neural transcription factors. The initial transcriptional response is relatively homogeneous among fibroblasts, suggesting that the early steps are not limiting for productive reprogramming. Instead, the later emergence of a competing myogenic program and variable transgene dynamics over time appear to be the major efficiency limits of direct reprogramming. Moreover, a transcriptional state, distinct from donor and target cell programs, is transiently induced in cells undergoing productive reprogramming. Our data provide a high-resolution approach for understanding transcriptome states during lineage differentiation.

  10. Dissecting direct reprogramming from fibroblast to neuron using single-cell RNA-seq

    PubMed Central

    Treutlein, Barbara; Lee, Qian Yi; Camp, J. Gray; Mall, Moritz; Koh, Winston; Shariati, Seyed Ali Mohammad; Sim, Sopheak; Neff, Norma F.; Skotheim, Jan M.; Wernig, Marius; Quake, Stephen R.

    2016-01-01

    Direct lineage reprogramming represents a remarkable conversion of cellular and transcriptome states1–3. However, the intermediates through which individual cells progress are largely undefined. Here we used single-cell RNA-seq4–7 at multiple time points to dissect direct reprogramming from mouse embryonic fibroblasts (MEFs) to induced neuronal (iN) cells. By deconstructing heterogeneity at each time point and ordering cells by transcriptome similarity, we find that the molecular reprogramming path is remarkably continuous. Overexpression of the proneural pioneer factor Ascl1 results in a well-defined initialization, causing cells to exit the cell cycle and re-focus gene expression through distinct neural transcription factors. The initial transcriptional response is relatively homogeneous among fibroblasts suggesting the early steps are not limiting for productive reprogramming. Instead, the later emergence of a competing myogenic program and variable transgene dynamics over time appear to be the major efficiency limits of direct reprogramming. Moreover, a transcriptional state, distinct from donor and target cell programs, is transiently induced in cells undergoing productive reprogramming. Our data provide a high-resolution approach for understanding transcriptome states during lineage differentiation. PMID:27281220

  11. Small Molecules Modulate Chromatin Accessibility to Promote NEUROG2-Mediated Fibroblast-to-Neuron Reprogramming.

    PubMed

    Smith, Derek K; Yang, Jianjing; Liu, Meng-Lu; Zhang, Chun-Li

    2016-11-08

    Pro-neural transcription factors and small molecules can induce the reprogramming of fibroblasts into functional neurons; however, the immediate-early molecular events that catalyze this conversion have not been well defined. We previously demonstrated that neurogenin 2 (NEUROG2), forskolin (F), and dorsomorphin (D) can reprogram fibroblasts into functional neurons with high efficiency. Here, we used this model to define the genetic and epigenetic events that initiate an acquisition of neuronal identity. We demonstrate that NEUROG2 is a pioneer factor, FD enhances chromatin accessibility and H3K27 acetylation, and synergistic transcription activated by these factors is essential to successful reprogramming. CREB1 promotes neuron survival and acts with NEUROG2 to upregulate SOX4, which co-activates NEUROD1 and NEUROD4. In addition, SOX4 targets SWI/SNF subunits and SOX4 knockdown results in extensive loss of open chromatin and abolishes reprogramming. Applying these insights, adult human glioblastoma cell and skin fibroblast reprogramming can be improved using SOX4 or chromatin-modifying chemicals.

  12. MYC mediates large oncosome-induced fibroblast reprogramming in prostate cancer.

    PubMed

    Minciacchi, Valentina R; Spinelli, Cristiana; Reis-Sobreiro, Mariana; Cavallini, Lorenzo; You, Sungyong; Zandian, Mandana; Li, Xiaohong; Chiarugi, Paola; Adam, Rosalyn M; Posadas, Edwin M; Viglietto, Giuseppe; Freeman, Michael R; Cocucci, Emanuele; Bhowmick, Neil A; Di Vizio, Dolores

    2017-02-15

    Communication between cancer cells and the tumor microenvironment results in the modulation of complex signaling networks that facilitate tumor progression. Here we describe a new mechanism of intercellular communication originating from large oncosomes (LO), which are cancer cell-derived, atypically large (1-10 μm) extracellular vesicles (EV). We demonstrate that, in the context of prostate cancer, LO harbor sustained AKT1 kinase activity, nominating them as active signaling platforms. Active AKT1 was detected in circulating EV from the plasma of metastatic prostate cancer patients and was LO specific. LO internalization induced reprogramming of human normal prostate fibroblasts as reflected by high levels of α-SMA, IL-6, and MMP9. In turn, LO-reprogrammed normal prostate fibroblasts stimulated endothelial tube formation in vitro and promoted tumor growth in mice. Activation of stromal MYC was critical for this reprogramming and for the sustained cellular responses elicited by LO both in vitro and in vivo in an AKT1-dependent manner. Inhibition of LO internalization prevented activation of MYC and impaired the tumor supporting properties of fibroblasts. Overall, our data show that prostate cancer-derived LO powerfully promote establishment of a tumor supportive environment by inducing a novel reprogramming of the stroma. This mechanism offers potential alternative options for patient treatment.

  13. Reprogramming of Human Fibroblasts to Induced Pluripotent Stem Cells with Sleeping Beauty Transposon-Based Stable Gene Delivery.

    PubMed

    Sebe, Attila; Ivics, Zoltán

    2016-01-01

    Human induced pluripotent stem (iPS) cells are a source of patient-specific pluripotent stem cells and resemble human embryonic stem (ES) cells in gene expression profiles, morphology, pluripotency, and in vitro differentiation potential. iPS cells are applied in disease modeling, drug screenings, toxicology screenings, and autologous cell therapy. In this protocol, we describe how to derive human iPS cells from fibroblasts by Sleeping Beauty (SB) transposon-mediated gene transfer of reprogramming factors. First, the components of the non-viral Sleeping Beauty transposon system, namely a transposon vector encoding reprogramming transcription factors and a helper plasmid expressing the SB transposase, are electroporated into human fibroblasts. The reprogramming cassette undergoes transposition from the transfected plasmids into the fibroblast genome, thereby resulting in stable delivery of the reprogramming factors. Reprogramming by using this protocol takes ~4 weeks, after which the iPS cells are isolated and clonally propagated.

  14. Triboelectric Nanogenerator Accelerates Highly Efficient Nonviral Direct Conversion and In Vivo Reprogramming of Fibroblasts to Functional Neuronal Cells.

    PubMed

    Jin, Yoonhee; Seo, Jungmok; Lee, Jung Seung; Shin, Sera; Park, Hyun-Ji; Min, Sungjin; Cheong, Eunji; Lee, Taeyoon; Cho, Seung-Woo

    2016-09-01

    Triboelectric nanogenerators (TENGs) can be an effective cell reprogramming platform for producing functional neuronal cells for therapeutic applications. Triboelectric stimulation accelerates nonviral direct conversion of functional induced neuronal cells from fibroblasts, increases the conversion efficiency, and induces highly matured neuronal phenotypes with improved electrophysiological functionalities. TENG devices may also be used for biomedical in vivo reprogramming.

  15. Role of MEF feeder cells in direct reprogramming of mousetail-tip fibroblasts.

    PubMed

    Chen, Mengfei; Sun, Xuerong; Jiang, Ruzhang; Shen, Wenjuan; Zhong, Xiufeng; Liu, Bingqian; Qi, Ying; Huang, Bing; Xiang, Andy Peng; Ge, Jian

    2009-12-01

    Pluripotent stem cells can be induced from somatic cells by the transcription factors Oct3/4, Sox2, c-Myc and Klf4 when co-cultured with mouse embryonic fibroblast (MEF) feeder cells. To date, the role of the feeder cells in the reprogramming process remains unclear. In this study, using a comparative analysis, we demonstrated that MEF feeder cells did not accelerate reprogramming or increase the frequency of induced pluripotent stem (iPS) cell colonies. However, feeder conditions did improve the growth of primary iPS colonies and were necessary for passaging the primary colonies after reprogramming was achieved. We further developed a feeder-free culture system for supporting iPS growth and sustaining pluripotency by adding bFGF and activin A (bFA) to the medium. These data will facilitate the generation of human iPS cells without animal feeders for regenerative medicine.

  16. Metabolic reprogramming of cancer-associated fibroblasts by TGF-β drives tumor growth

    PubMed Central

    Guido, Carmela; Whitaker-Menezes, Diana; Capparelli, Claudia; Balliet, Renee; Lin, Zhao; Pestell, Richard G.; Howell, Anthony; Aquila, Saveria; Andò, Sebastiano; Martinez-Outschoorn, Ubaldo; Sotgia, Federica; Lisanti, Michael P.

    2012-01-01

    We have previously shown that a loss of stromal Cav-1 is a biomarker of poor prognosis in breast cancers. Mechanistically, a loss of Cav-1 induces the metabolic reprogramming of stromal cells, with increased autophagy/mitophagy, mitochondrial dysfunction and aerobic glycolysis. As a consequence, Cav-1-low CAFs generate nutrients (such as L-lactate) and chemical building blocks that fuel mitochondrial metabolism and the anabolic growth of adjacent breast cancer cells. It is also known that a loss of Cav-1 is associated with hyperactive TGF-β signaling. However, it remains unknown whether hyperactivation of the TGF-β signaling pathway contributes to the metabolic reprogramming of Cav-1-low CAFs. To address these issues, we overexpressed TGF-β ligands and the TGF-β receptor I (TGFβ-RI) in stromal fibroblasts and breast cancer cells. Here, we show that the role of TGF-β in tumorigenesis is compartment-specific, and that TGF-β promotes tumorigenesis by shifting cancer-associated fibroblasts toward catabolic metabolism. Importantly, the tumor-promoting effects of TGF-β are independent of the cell type generating TGF-β. Thus, stromal-derived TGF-β activates signaling in stromal cells in an autocrine fashion, leading to fibroblast activation, as judged by increased expression of myofibroblast markers, and metabolic reprogramming, with a shift toward catabolic metabolism and oxidative stress. We also show that TGF-β-activated fibroblasts promote the mitochondrial activity of adjacent cancer cells, and in a xenograft model, enhancing the growth of breast cancer cells, independently of angiogenesis. Conversely, activation of the TGF-β pathway in cancer cells does not influence tumor growth, but cancer cell-derived-TGF-β ligands affect stromal cells in a paracrine fashion, leading to fibroblast activation and enhanced tumor growth. In conclusion, ligand-dependent or cell-autonomous activation of the TGF-β pathway in stromal cells induces their metabolic

  17. PIWI Proteins Are Dispensable for Mouse Somatic Development and Reprogramming of Fibroblasts into Pluripotent Stem Cells

    PubMed Central

    Cheng, Ee-Chun; Kang, Dongwan; Wang, Zhong; Lin, Haifan

    2014-01-01

    PIWI proteins play essential and conserved roles in germline development, including germline stem cell maintenance and meiosis. Because germline regulators such as OCT4, NANOG, and SOX2 are known to be potent factors that reprogram differentiated somatic cells into induced pluripotent stem cells (iPSCs), we investigated whether the PIWI protein family is involved in iPSC production. We find that all three mouse Piwi genes, Miwi, Mili, and Miwi2, are expressed in embryonic stem cells (ESCs) at higher levels than in fibroblasts, with Mili being the highest. However, mice lacking all three Piwi genes are viable and female fertile, and are only male sterile. Furthermore, embryonic fibroblasts derived from Miwi/Mili/Miwi2 triple knockout embryos can be efficiently reprogrammed into iPS cells. These iPS cells expressed pluripotency markers and were capable of differentiating into all three germ layers in teratoma assays. Genome-wide expression profiling reveals that the triple knockout iPS cells are very similar to littermate control iPS cells. These results indicate that PIWI proteins are dispensable for direct reprogramming of mouse fibroblasts. PMID:25238487

  18. Tissue-engineered 3-dimensional (3D) microenvironment enhances the direct reprogramming of fibroblasts into cardiomyocytes by microRNAs

    PubMed Central

    Li, Yanzhen; Dal-Pra, Sophie; Mirotsou, Maria; Jayawardena, Tilanthi M.; Hodgkinson, Conrad P.; Bursac, Nenad; Dzau, Victor J.

    2016-01-01

    We have recently shown that a combination of microRNAs, miR combo, can directly reprogram cardiac fibroblasts into functional cardiomyocytes in vitro and in vivo. Reprogramming of cardiac fibroblasts by miR combo in vivo is associated with improved cardiac function following myocardial infarction. However, the efficiency of direct reprogramming in vitro is relatively modest and new strategies beyond the traditional two-dimensional (2D) culture should be identified to improve reprogramming process. Here, we report that a tissue-engineered three-dimensional (3D) hydrogel environment enhanced miR combo reprogramming of neonatal cardiac and tail-tip fibroblasts. This was associated with significantly increased MMPs expression in 3D vs. 2D cultured cells, while pharmacological inhibition of MMPs blocked the effect of the 3D culture on enhanced miR combo mediated reprogramming. We conclude that 3D tissue-engineered environment can enhance the direct reprogramming of fibroblasts to cardiomyocytes via a MMP-dependent mechanism. PMID:27941896

  19. Direct reprogramming of mouse fibroblasts into cardiomyocytes with chemical cocktails.

    PubMed

    Fu, Yanbin; Huang, Chenwen; Xu, Xinxiu; Gu, Haifeng; Ye, Youqiong; Jiang, Cizhong; Qiu, Zilong; Xie, Xin

    2015-09-01

    The direct conversion, or transdifferentiation, of non-cardiac cells into cardiomyocytes by forced expression of transcription factors and microRNAs provides promising approaches for cardiac regeneration. However, genetic manipulations raise safety concerns and are thus not desirable in most clinical applications. The discovery of full chemically induced pluripotent stem cells suggest the possibility of replacing transcription factors with chemical cocktails. Here, we report the generation of automatically beating cardiomyocyte-like cells from mouse fibroblasts using only chemical cocktails. These chemical-induced cardiomyocyte-like cells (CiCMs) express cardiomyocyte-specific markers, exhibit sarcomeric organization, and possess typical cardiac calcium flux and electrophysiological features. Genetic lineage tracing confirms the fibroblast origin of these CiCMs. Further studies show the generation of CiCMs passes through a cardiac progenitor stage instead of a pluripotent stage. Bypassing the use of viral-derived factors, this proof of concept study lays a foundation for in vivo cardiac transdifferentiation with pharmacological agents and possibly safer treatment of heart failure.

  20. Direct reprogramming of human fibroblasts into sweat gland-like cells.

    PubMed

    Zhao, Zhiliang; Xu, Mengyao; Wu, Meng; Ma, Kui; Sun, Mengli; Tian, Xiaocheng; Zhang, Cuiping; Fu, Xiaobing

    2015-01-01

    The skin of patients with an extensive deep burn injury is repaired by a process that leaves a hypertrophic scar without sweat glands and therefore loses the function of perspiration. The aim of this study was to identify whether the key factors related to sweat gland development could directly reprogram fibroblasts into sweat gland-like cells. After introducing the NF-κB and Lef-1 genes into fibroblasts, we found that stably transfected fibroblasts expressed specific markers of sweat glands, including CEA, CK7, CK14 and CK19, both at the protein and mRNA levels. The immunofluorescence staining also showed positive expression of CEA, CK7, CK14 and CK19 in induced fibroblasts, but there were no positive cells in the control groups. The expression of Shh and Cyclin D1, downstream genes of NF-κB and Lef-1, were also significantly increased during regeneration. The induced fibroblasts were implanted into an animal model. Twenty days later, iodine-starch perspiration tests showed that 7 out of the 10 cell-treated paws were positive for perspiration, with a distinctive black point-like area appearing in the center of the paw. Contralateral paws tested negative. Histological examination of skin biopsies from experimental and control paws revealed that sweat glands were fully reconstructed in the test paws, with integral, secretory and ductal portions, but were not present in the control paws. This is the first report of successful reprogramming of fibroblasts into sweat gland-like cells, which will provide a new cell source for sweat gland regeneration in patients with extensive deep burns.

  1. CD44 Is a Negative Cell Surface Marker for Pluripotent Stem Cell Identification during Human Fibroblast Reprogramming

    PubMed Central

    Vaz, Candida; Tanavde, Vivek; Lakshmipathy, Uma

    2014-01-01

    Induced pluripotent stem cells (iPSCs) are promising tools for disease research and cell therapy. One of the critical steps in establishing iPSC lines is the early identification of fully reprogrammed colonies among unreprogrammed fibroblasts and partially reprogrammed intermediates. Currently, colony morphology and pluripotent stem cell surface markers are used to identify iPSC colonies. Through additional clonal characterization, we show that these tools fail to distinguish partially reprogrammed intermediates from fully reprogrammed iPSCs. Thus, they can lead to the selection of suboptimal clones for expansion. A subsequent global transcriptome analysis revealed that the cell adhesion protein CD44 is a marker that differentiates between partially and fully reprogrammed cells. Immunohistochemistry and flow cytometry confirmed that CD44 is highly expressed in the human parental fibroblasts used for the reprogramming experiments. It is gradually lost throughout the reprogramming process and is absent in fully established iPSCs. When used in conjunction with pluripotent cell markers, CD44 staining results in the clear identification of fully reprogrammed cells. This combination of positive and negative surface markers allows for easier and more accurate iPSC detection and selection, thus reducing the effort spent on suboptimal iPSC clones. PMID:24416407

  2. Second generation codon optimized minicircle (CoMiC) for nonviral reprogramming of human adult fibroblasts.

    PubMed

    Diecke, Sebastian; Lisowski, Leszek; Kooreman, Nigel G; Wu, Joseph C

    2014-01-01

    The ability to induce pluripotency in somatic cells is one of the most important scientific achievements in the fields of stem cell research and regenerative medicine. This technique allows researchers to obtain pluripotent stem cells without the controversial use of embryos, providing a novel and powerful tool for disease modeling and drug screening approaches. However, using viruses for the delivery of reprogramming genes and transcription factors may result in integration into the host genome and cause random mutations within the target cell, thus limiting the use of these cells for downstream applications. To overcome this limitation, various non-integrating techniques, including Sendai virus, mRNA, minicircle, and plasmid-based methods, have recently been developed. Utilizing a newly developed codon optimized 4-in-1 minicircle (CoMiC), we were able to reprogram human adult fibroblasts using chemically defined media and without the need for feeder cells.

  3. Heart Development, Diseases, and Regeneration - New Approaches From Innervation, Fibroblasts, and Reprogramming.

    PubMed

    Ieda, Masaki

    2016-09-23

    It is well known that cardiac function is tightly controlled by neural activity; however, the molecular mechanism of cardiac innervation during development and the relationship with heart disease remain undetermined. My work has revealed the molecular networks that govern cardiac innervation and its critical roles in heart diseases such as silent myocardial ischemia and arrhythmias. Cardiomyocytes proliferate during embryonic development, but lose their proliferative capacity after birth. Cardiac fibroblasts are a major source of cells during fibrosis and induce cardiac hypertrophy after myocardial injury in the adult heart. Despite the importance of fibroblasts in the adult heart, the role of fibroblasts in embryonic heart development was previously not determined. I demonstrated that cardiac fibroblasts play important roles in myocardial growth and cardiomyocyte proliferation during embryonic development, and I identified key paracrine factors and signaling pathways. In contrast to embryonic cardiomyocytes, adult cardiomyocytes have little regenerative capacity, leading to heart failure and high mortality rates after myocardial infarction. Leveraging the knowledge of developmental biology, I identified cardiac reprogramming factors that can directly convert resident cardiac fibroblasts into cardiomyocytes for heart regeneration. These findings greatly improved our understanding of heart development and diseases, and provide a new strategy for heart regenerative therapy. (Circ J 2016; 80: 2081-2088).

  4. Reprogramming of human fibroblasts to pluripotent stem cells using mRNA of four transcription factors

    SciTech Connect

    Yakubov, Eduard; Rechavi, Gidi; Rozenblatt, Shmuel; Givol, David

    2010-03-26

    Reprogramming of differentiated cells into induced pluripotent cells (iPS) was accomplished in 2006 by expressing four, or less, embryonic stem cell (ESC)-specific transcription factors. Due to the possible danger of DNA damage and the potential tumorigenicity associated with such DNA damage, attempts were made to minimize DNA integration by the vectors involved in this process without complete success. Here we present a method of using RNA transfection as a tool for reprogramming human fibroblasts to iPS. We used RNA synthesized in vitro from cDNA of the same reprogramming four transcription factors. After transfection of the RNA, we show intracellular expression and nuclear localization of the respective proteins in at least 70% of the cells. We used five consecutive transfections to support continuous protein expression resulting in the formation of iPS colonies that express alkaline phosphatase and several ESC markers and that can be expanded. This method completely avoids DNA integration and may be developed to replace the use of DNA vectors in the formation of iPS.

  5. Histone deacetylase inhibitor valproic acid promotes the induction of pluripotency in mouse fibroblasts by suppressing reprogramming-induced senescence stress

    SciTech Connect

    Zhai, Yingying; Chen, Xi; Yu, Dehai; Li, Tao; Cui, Jiuwei; Wang, Guanjun; Hu, Ji-Fan; Li, Wei

    2015-09-10

    Histone deacetylase inhibitor valproic acid (VPA) has been used to increase the reprogramming efficiency of induced pluripotent stem cell (iPSC) from somatic cells, yet the specific molecular mechanisms underlying this effect is unknown. Here, we demonstrate that reprogramming with lentiviruses carrying the iPSC-inducing factors (Oct4-Sox2-Klf4-cMyc, OSKM) caused senescence in mouse fibroblasts, establishing a stress barrier for cell reprogramming. Administration of VPA protected cells from reprogramming-induced senescent stress. Using an in vitro pre-mature senescence model, we found that VPA treatment increased cell proliferation and inhibited apoptosis through the suppression of the p16/p21 pathway. In addition, VPA also inhibited the G2/M phase blockage derived from the senescence stress. These findings highlight the role of VPA in breaking the cell senescence barrier required for the induction of pluripotency. - Highlights: • Histone deacetylase inhibitor valproic acid enhances iPSC induction. • Valproic acid suppresses reprogramming-induced senescence stress. • Valproic acid downregulates the p16/p21 pathway in reprogramming. • This study demonstrates a new mechanistic role of valproic acid in enhancing reprogramming.

  6. Multilayered Nanoparticles for Gene Delivery Used to Reprogram Human Foreskin Fibroblasts to Neurospheres

    PubMed Central

    Watson, Andre; Ren, Liyun; Mixon, Amanda; Kotha, Shiva P.

    2015-01-01

    Polycationic nanocomplexes are a robust means for achieving nucleic acid condensation and efficient intracellular gene deliveries. To enhance delivery, a multilayered nanoparticle consisting of a core of electrostatically bound elements was used. These included a histone-mimetic peptides, poly-l-arginine and poly-d-glutamic acid was coated with silicate before surface functionalization with poly-l-arginine. Transfection efficiencies and duration of expression were similar when using green fluorescent protein (GFP) plasmid DNA (pDNA) or GFP mRNA. These nanoparticles demonstrated significantly higher (>100%) and significantly longer (15 vs. 4 days) transfection efficiencies in comparison to a commercial transfection agent (Lipofectamine 2000). Reprogramming of human foreskin fibroblasts using mRNA to the Sox2 transcription factor resulted in three-fold higher neurosphere formation in comparison to the commercial reagent. These results demonstrate the potential of these nanoparticles as ideal vectors for gene delivery. PMID:25687130

  7. Non-viral reprogramming of fibroblasts into induced pluripotent stem cells by Sleeping Beauty and piggyBac transposons.

    PubMed

    Talluri, Thirumala R; Kumar, Dharmendra; Glage, Silke; Garrels, Wiebke; Ivics, Zoltan; Debowski, Katharina; Behr, Rüdiger; Kues, Wilfried A

    2014-07-18

    The generation of induced pluripotent stem (iPS) cells represents a promising approach for innovative cell therapies. The original method requires viral transduction of several reprogramming factors, which may be associated with an increased risk of tumorigenicity. Transposition of reprogramming cassettes represents a recent alternative to viral approaches. Since binary transposons can be produced as common plasmids they provide a safe and cost-efficient alternative to viral delivery methods. Here, we compared the efficiency of two different transposon systems, Sleeping Beauty (SB) and piggyBac (PB), for the generation of murine iPS. Murine fibroblasts derived from an inbred BL/6 mouse line carrying a pluripotency reporter, Oct4-EGFP, and fibroblasts derived from outbred NMRI mice were employed for reprogramming. Both transposon systems resulted in the successful isolation of murine iPS cell lines. The reduction of the core reprogramming factors to omit the proto-oncogene c-Myc was compatible with iPS cell line derivation, albeit with reduced reprogramming efficiencies. The transposon-derived iPS cells featured typical hallmarks of pluripotency, including teratoma growth in immunodeficient mice. Thus SB and PB transposons represent a promising non-viral approach for iPS cell derivation.

  8. Peptide-enhanced mRNA transfection in cultured mouse cardiac fibroblasts and direct reprogramming towards cardiomyocyte-like cells.

    PubMed

    Lee, Kunwoo; Yu, Pengzhi; Lingampalli, Nithya; Kim, Hyun Jin; Tang, Richard; Murthy, Niren

    2015-01-01

    The treatment of myocardial infarction is a major challenge in medicine due to the inability of heart tissue to regenerate. Direct reprogramming of endogenous cardiac fibroblasts into functional cardiomyocytes via the delivery of transcription factor mRNAs has the potential to regenerate cardiac tissue and to treat heart failure. Even though mRNA delivery to cardiac fibroblasts has the therapeutic potential, mRNA transfection in cardiac fibroblasts has been challenging. Herein, we develop an efficient mRNA transfection in cultured mouse cardiac fibroblasts via a polyarginine-fused heart-targeting peptide and lipofectamine complex, termed C-Lipo and demonstrate the partial direct reprogramming of cardiac fibroblasts towards cardiomyocyte cells. C-Lipo enabled the mRNA-induced direct cardiac reprogramming due to its efficient transfection with low toxicity, which allowed for multiple transfections of Gata4, Mef2c, and Tbx5 (GMT) mRNAs for a period of 2 weeks. The induced cardiomyocyte-like cells had α-MHC promoter-driven GFP expression and striated cardiac muscle structure from α-actinin immunohistochemistry. GMT mRNA transfection of cultured mouse cardiac fibroblasts via C-Lipo significantly increased expression of the cardiomyocyte marker genes, Actc1, Actn2, Gja1, Hand2, and Tnnt2, after 2 weeks of transfection. Moreover, this study provides the first direct evidence that the stoichiometry of the GMT reprogramming factors influence the expression of cardiomyocyte marker genes. Our results demonstrate that mRNA delivery is a potential approach for cardiomyocyte generation.

  9. 199 EFFECTS OF REPROGRAMMING-CONDITIONED MEDIUM ON ULTRAVIOLET RAY A-DAMAGED HUMAN DERMAL FIBROBLASTS.

    PubMed

    Kang, J; Lee, S G; Kang, J H; Park, S-M; Heo, S Y; Lee, S Y; Kim, S; Lo, E; Ahn, K S; Shim, H

    2016-01-01

    Ultraviolet ray A (UVA) is an electromagnetic light with a long wavelength from the sun. The penetration of UVA deep into the human dermis causes changes in cells, such as DNA fragmentation, apoptosis, and senescence, eventually leading a decline of proliferation and wound-healing ability. These changes induced by UVA exposure are similar to those seen in the process of stem cell differentiation. We postulated that the condition that reverses cellular differentiation may alleviate the UVA-induced damage in skin cells. Human dermal fibroblasts (HDF) could be reprogrammed to induced pluripotent stem cells (iPSC). Conditioned medium (CM) was prepared during the process of iPSC reprogramming (referred to as Repro-CM). The UVA-irradiated HDF were cultured in Repro-CM for 24h. In comparison with CM prepared from the culture of normal HDF and iPSC (referred to as HDF-CM and iPSC-CM, respectively), effects of Repro-CM on UVA-irradiated cells were investigated. Viability, wound-healing ability, apoptosis, and senescence of HDF were analysed by WST-1 assay, scratch assay, Annexin V assay, and senescence-associated β-galactosidase assay, respectively. Upon recovering from the UVA-induced damage, viability and wound-healing ability of HDF were significantly different (P<0.05) among the treatments in the order of Repro-, HDF-, and iPSC-CM. In the same context, apoptosis and senescence were significantly different (P<0.05) in the order of iPSC-, HDF-, and Repro-CM. Interestingly, iPSC-CM did not substantially ameliorate UVA-induced damage, suggesting that the conditions optimized to pluripotent stem cells may not be suitable for the recovery from damage in terminally differentiated cells, such as fibroblasts. The RNA-seq analysis was performed to assess the genome-wide transcriptional profile in the process of recovery. Repro- and HDF-CM were categorized more closely than iPSC-CM in hierarchical cluster analysis. In comparison with iPSC-CM, the up-regulated genes by Repro

  10. Reprogramming of Normal Fibroblasts into Cancer-Associated Fibroblasts by miRNAs-Mediated CCL2/VEGFA Signaling

    PubMed Central

    Shen, Hua; Yu, Xiaobo; Yang, Fengming; Zhang, Zhihua; Shen, Jianxin; Sun, Jin; Choksi, Swati; Jitkaew, Siriporn; Shu, Yongqian

    2016-01-01

    Cancer-associated fibroblasts (CAFs), the most common constituent of the tumor stoma, are known to promote tumor initiation, progression and metastasis. However, the mechanism of how cancer cells transform normal fibroblasts (NFs) into CAFs is largely unknown. In this study, we determined the contribution of miRNAs in the transformation of NFs into CAFs. We found that miR-1 and miR-206 were down-regulated, whereas miR-31 was up-regulated in lung CAFs when compared with matched NFs. Importantly, modifying the expression of these three deregulated miRNAs induced a functional conversion of NFs into CAFs and vice versa. When the miRNA-reprogrammed NFs and CAFs were co-cultured with lung cancer cells (LCCs), a similar pattern of cytokine expression profiling were observed between two groups. Using a combination of cytokine expression profiling and miRNAs algorithms, we identified VEGFA/CCL2 and FOXO3a as direct targets of miR-1, miR-206 and miR-31, respectively. Importantly, systemic delivery of anti-VEGFA/CCL2 or pre-miR-1, pre-miR-206 and anti-miR-31 significantly inhibited tumor angiogenesis, TAMs accumulation, tumor growth and lung metastasis. Our results show that miRNAs-mediated FOXO3a/VEGF/CCL2 signaling plays a prominent role in LCCs-mediated NFs into CAFs, which may have clinical implications for providing novel biomarker(s) and potential therapeutic target(s) of lung cancer in the future. PMID:27541266

  11. Substrate-mediated reprogramming of human fibroblasts into neural crest stem-like cells and their applications in neural repair.

    PubMed

    Tseng, Ting-Chen; Hsieh, Fu-Yu; Dai, Niann-Tzyy; Hsu, Shan-Hui

    2016-09-01

    Cell- and gene-based therapies have emerged as promising strategies for treating neurological diseases. The sources of neural stem cells are limited while the induced pluripotent stem (iPS) cells have risk of tumor formation. Here, we proposed the generation of self-renewable, multipotent, and neural lineage-related neural crest stem-like cells by chitosan substrate-mediated gene transfer of a single factor forkhead box D3 (FOXD3) for the use in neural repair. A simple, non-toxic, substrate-mediated method was applied to deliver the naked FOXD3 plasmid into human fibroblasts. The transfection of FOXD3 increased cell proliferation and up-regulated the neural crest marker genes (FOXD3, SOX2, and CD271), stemness marker genes (OCT4, NANOG, and SOX2), and neural lineage-related genes (Nestin, β-tubulin and GFAP). The expression levels of stemness marker genes and neural crest maker genes in the FOXD3-transfected fibroblasts were maintained until the fifth passage. The FOXD3 reprogrammed fibroblasts based on the new method significantly rescued the neural function of the impaired zebrafish. The chitosan substrate-mediated delivery of naked plasmid showed feasibility in reprogramming somatic cells. Particularly, the FOXD3 reprogrammed fibroblasts hold promise as an easily accessible cellular source with neural crest stem-like behavior for treating neural diseases in the future.

  12. An atomic-force-microscopy study of the structure of surface layers of intact fibroblasts

    NASA Astrophysics Data System (ADS)

    Khalisov, M. M.; Ankudinov, A. V.; Penniyaynen, V. A.; Nyapshaev, I. A.; Kipenko, A. V.; Timoshchuk, K. I.; Podzorova, S. A.; Krylov, B. V.

    2017-02-01

    Intact embryonic fibroblasts on a collagen-treated substrate have been studied by atomic-force microscopy (AFM) using probes of two types: (i) standard probes with tip curvature radii of 2-10 nm and (ii) special probes with a calibrated 325-nm SiO2 ball radius at the tip apex. It is established that, irrespective of probe type, the average maximum fibroblast height is on a level of 1.7 μm and the average stiffness of the probe-cell contact amounts to 16.5 mN/m. The obtained AFM data reveal a peculiarity of the fibroblast structure, whereby its external layers move as a rigid shell relative to the interior and can be pressed inside to a depth dependent on the load only.

  13. Reprogramming of Mouse, Rat, Pig, and Human Fibroblasts into iPS Cells

    PubMed Central

    Wu, Sean M.

    2012-01-01

    The induction of pluripotency in somatic cells by transcription factor overexpression has been widely regarded as one of the major breakthroughs in stem cell biology within this decade. The generation of these induced pluripotent stem cells (iPSCs) has enabled investigators to develop in vitro disease models for biological discovery and drug screening, and in the future, patient-specific therapy for tissue or organ regeneration. While new technologies for reprogramming are continually being discovered, the availability of iPSCs from different species is also increasing rapidly. Comparison of iPSCs across species may provide new insights into key aspects of pluripotency and early embryonic development. iPSCs from large animals may enable the generation of genetically-modified large animal models or potentially transplantable donor tissues or organs. In this unit, we describe the procedure for the generation of iPSCs from mouse, rat, pig and human fibroblasts. We focus on lenti- and retroviral infection as the main platform for pluripotent transcription factor overexpression since these reagents are widely-available and remain the most efficient way to generate iPSC colonies. We hope to illustrate the basic process for iPSC generation in these four species in such a way that would enable the lowering of the entry barrier into iPSC biology by new investigators. PMID:22237859

  14. A rare human syndrome provides genetic evidence that WNT signaling is required for reprogramming of fibroblasts to induced pluripotent stem cells.

    PubMed

    Ross, Jason; Busch, Julia; Mintz, Ellen; Ng, Damian; Stanley, Alexandra; Brafman, David; Sutton, V Reid; Van den Veyver, Ignatia; Willert, Karl

    2014-12-11

    WNT signaling promotes the reprogramming of somatic cells to an induced pluripotent state. We provide genetic evidence that WNT signaling is a requisite step during the induction of pluripotency. Fibroblasts from individuals with focal dermal hypoplasia (FDH), a rare genetic syndrome caused by mutations in the essential WNT processing enzyme PORCN, fail to reprogram with standard methods. This blockade in reprogramming is overcome by ectopic WNT signaling and PORCN overexpression, thus demonstrating that WNT signaling is essential for reprogramming. The rescue of reprogramming is critically dependent on the level of WNT signaling: steady baseline activation of the WNT pathway yields karyotypically normal iPSCs, whereas daily stimulation with Wnt3a produces FDH-iPSCs with severely abnormal karyotypes. Therefore, although WNT signaling is required for cellular reprogramming, inappropriate activation of WNT signaling induces chromosomal instability, highlighting the precarious nature of ectopic WNT activation and its tight relationship with oncogenic transformation.

  15. Signalling Through Retinoic Acid Receptors is Required for Reprogramming of Both Mouse Embryonic Fibroblast Cells and Epiblast Stem Cells to Induced Pluripotent Stem Cells.

    PubMed

    Yang, Jian; Wang, Wei; Ooi, Jolene; Campos, Lia S; Lu, Liming; Liu, Pentao

    2015-05-01

    We previously demonstrated that coexpressing retinoic acid (RA) receptor gamma and liver receptor homolog-1 (LRH1 or NR5A2) with OCT4, MYC, KLF4, and SOX2 (4F) rapidly reprograms mouse embryonic fibroblast cells (MEFs) into induced pluripotent stem cells (iPSCs). Here, we further explore the role of RA in reprogramming and report that the six factors (6F) efficiently and directly reprogram MEFs into integration-free iPSCs in defined medium (N2B27) in the absence of feeder cells. Through genetic and chemical approaches, we find that RA signalling is essential, in a highly dose-sensitive manner, for MEF reprogramming. The removal of exogenous RA from N2B27, the inhibition of endogenous RA synthesis or the expression of a dominant-negative form of RARA severely impedes reprogramming. By contrast, supplementing N2B27 with various retinoids substantially boosts reprogramming. In addition, when coexpressed with LRH1, RA receptors (RARs) can promote reprogramming in the absence of both exogenous and endogenously synthesized RA. Remarkably, the reprogramming of epiblast stem cells into embryonic stem cell-like cells also requires low levels of RA, which can modulate Wnt signalling through physical interactions of RARs with β-catenin. These results highlight the important functions of RA signalling in reprogramming somatic cells and primed stem cells to naïve pluripotency. Stem Cells 2015;33:1390-1404.

  16. Generation of colonies of induced trophoblast cells during standard reprogramming of porcine fibroblasts to induced pluripotent stem cells.

    PubMed

    Ezashi, Toshihiko; Matsuyama, Haruyo; Telugu, Bhanu Prakash V L; Roberts, R Michael

    2011-10-01

    During reprogramming of porcine mesenchymal cells with a four-factor (POU5F1/SOX2/KLF4/MYC) mixture of vectors, a fraction of the colonies had an atypical phenotype and arose earlier than the recognizable porcine induced pluripotent stem (iPS) cell colonies. Within days after each passage, patches of cells with an epithelial phenotype formed raised domes, particularly under 20% O(2) conditions. Relative to gene expression of the iPS cells, there was up-regulation of genes for transcription factors associated with trophoblast (TR) lineage emergence, e.g., GATA2, PPARG, MSX2, DLX3, HAND1, GCM1, CDX2, ID2, ELF5, TCFAP2C, and TEAD4 and for genes required for synthesis of products more typical of differentiated TR, such as steroids (HSD17B1, CYP11A1, and STAR), pregnancy-associated glycoproteins (PAG6), and select cytokines (IFND, IFNG, and IL1B). Although POU5F1 was down-regulated relative to that in iPS cells, it was not silenced in the induced TR (iTR) cells over continued passage. Like iPS cells, iTR cells did not senesce on extended passage and displayed high telomerase activity. Upon xenografting into immunodeficient mice, iTR cells formed nonhemorrhagic teratomas composed largely of layers of epithelium expressing TR markers. When cultured under conditions that promoted embryoid body formation, iTR cells formed floating spheres consisting of a single epithelial sheet whose cells were tethered laterally by desmosome-like structures. In conclusion, reprogramming of porcine fibroblasts to iPS cells generates, as a by-product, colonies composed of self-renewing populations of TR cells, possibly containing TR stem cells.

  17. Two factor-based reprogramming of rodent and human fibroblasts into Schwann cells

    PubMed Central

    Mazzara, Pietro Giuseppe; Massimino, Luca; Pellegatta, Marta; Ronchi, Giulia; Ricca, Alessandra; Iannielli, Angelo; Giannelli, Serena Gea; Cursi, Marco; Cancellieri, Cinzia; Sessa, Alessandro; Del Carro, Ubaldo; Quattrini, Angelo; Geuna, Stefano; Gritti, Angela; Taveggia, Carla; Broccoli, Vania

    2017-01-01

    Schwann cells (SCs) generate the myelin wrapping of peripheral nerve axons and are promising candidates for cell therapy. However, to date a renewable source of SCs is lacking. In this study, we show the conversion of skin fibroblasts into induced Schwann cells (iSCs) by driving the expression of two transcription factors, Sox10 and Egr2. iSCs resembled primary SCs in global gene expression profiling and PNS identity. In vitro, iSCs wrapped axons generating compact myelin sheaths with regular nodal structures. Conversely, iSCs from Twitcher mice showed a severe loss in their myelinogenic potential, demonstrating that iSCs can be an attractive system for in vitro modelling of PNS diseases. The same two factors were sufficient to convert human fibroblasts into iSCs as defined by distinctive molecular and functional traits. Generating iSCs through direct conversion of somatic cells offers opportunities for in vitro disease modelling and regenerative therapies. PMID:28169300

  18. Alkaline Phosphatase-Positive Immortal Mouse Embryo Fibroblasts Are Cells in a Transitional Reprogramming State Induced to Face Environmental Stresses

    PubMed Central

    Evangelista, Monica; Baroudi, Mariama El; Rizzo, Milena; Tuccoli, Andrea; Poliseno, Laura; Pellegrini, Marco; Rainaldi, Giuseppe

    2015-01-01

    In this study, we report that immortal mouse embryonic fibroblasts (I-MEFs) have a baseline level of cells positive for alkaline phosphatase (AP+) staining. Environmental stresses, including long-lasting growth in the absence of expansion and treatment with drugs, enhance the frequency of AP+ I-MEFs. By adapting fast red AP staining to the sorting procedure, we separated AP+ and AP− I-MEFs and demonstrated that the differentially expressed genes are consistent with a reprogrammed phenotype. In particular, we found that sestrin 1 is upregulated in AP+ I-MEFs. We focused on this gene and demonstrated that increased sestrin 1 expression is accompanied by the growth of I-MEFs in the absence of expansion and occurs before the formation of AP+ I-MEFs. Together with sestrin 1 upregulation, we found that AP+ I-MEFs accumulated in the G1 phase of the cell cycle, suggesting that the two events are causally related. Accordingly, we found that silencing sestrin 1 expression reduced the frequency and G1 accumulation of AP+ I-MEFs. Taken together, our data suggested that I-MEFs stressed by environmental changes acquire the AP+ phenotype and achieve a quiescent state characterized by a new transcriptional network. PMID:26740745

  19. Predictors of intact and C-terminal fibroblast growth factor 23 in Gambian children

    PubMed Central

    Braithwaite, Vickie; Jones, Kerry S; Assar, Shima; Schoenmakers, Inez; Prentice, Ann

    2013-01-01

    Elevated C-terminal fibroblast growth factor 23 (C-FGF23) concentrations have been reported in Gambian children with and without putative Ca-deficiency rickets. The aims of this study were to investigate whether i) elevated C-FGF23 concentrations in Gambian children persist long term; ii) they are associated with higher intact FGF23 concentrations (I-FGF23), poor iron status and shorter 25-hydroxyvitamin D half-life (25OHD-t1/2); and iii) the persistence and predictors of elevated FGF23 concentrations differ between children with and without a history of rickets. Children (8–16 years, n=64) with a history of rickets and a C-FGF23 concentration >125 RU/ml (bone deformity (BD), n=20) and local community children with a previously measured elevated C-FGF23 concentration (LC+, n=20) or a previously measured C-FGF23 concentration within the normal range (LC−, n=24) participated. BD children had no remaining signs of bone deformities. C-FGF23 concentration had normalised in BD children, but remained elevated in LC+ children. All the children had I-FGF23 concentration within the normal range, but I-FGF23 concentration was higher and iron status poorer in LC+ children. 1,25-dihydroxyvitamin D was the strongest negative predictor of I-FGF23 concentration (R2=18%; P=0.0006) and soluble transferrin receptor was the strongest positive predictor of C-FGF23 concentration (R2=33%; P≤0.0001). C-FGF23 and I-FGF23 concentrations were poorly correlated with each other (R2=5.3%; P=0.07). 25OHD-t1/2 was shorter in BD children than in LC− children (mean (s.d.): 24.5 (6.1) and 31.5 (11.5) days respectively; P=0.05). This study demonstrated that elevated C-FGF23 concentrations normalised over time in Gambian children with a history of rickets but not in local children, suggesting a different aetiology; that children with resolved rickets had a shorter 25OHD-t1/2, suggesting a long-standing increased expenditure of 25OHD, and that iron deficiency is a predictor of elevated C

  20. Transcription factor–mediated reprogramming of fibroblasts to expandable, myelinogenic oligodendrocyte progenitor cells

    PubMed Central

    Najm, Fadi J.; Lager, Angela M.; Zaremba, Anita; Wyatt, Krysta; Caprariello, Andrew V.; Factor, Daniel C.; Karl, Robert T.; Maeda, Tadao; Miller, Robert H.; Tesar, Paul J.

    2013-01-01

    Cell-based therapies for myelin disorders, such as multiple sclerosis and leukodystrophies, require technologies to generate functional oligodendrocyte progenitor cells. Here we describe direct conversion of mouse embryonic and lung fibroblasts to “induced” oligodendrocyte progenitor cells (iOPCs) using sets of either eight or three defined transcription factors. iOPCs exhibit a bipolar morphology and global gene expression profile consistent with bona fide OPCs. They can be expanded in vitro for at least five passages while retaining the ability to differentiate into multiprocessed oligodendrocytes. When transplanted to hypomyelinated mice, iOPCs are capable of ensheathing host axons and generating compact myelin. Lineage conversion of somatic cells to expandable iOPCs provides a strategy to study the molecular control of oligodendrocyte lineage identity and may facilitate neurological disease modeling and autologous remyelinating therapies. PMID:23584611

  1. Metabolic reprogramming of carcinoma-associated fibroblasts and its impact on metabolic heterogeneity of tumors.

    PubMed

    Wu, Duojiao; Zhuo, Leying; Wang, Xiangdong

    2017-04-01

    Tumor metabolism is characterized with up-regulated glucose uptake and glycolytic rate of tumor cells as the source of ATP and tumors growth, and regulated by a poorly defined combination of cell-intrinsic and extrinsic factors. Metabolic heterogeneity of human tumors is dependent upon the mutational status of specific oncogenes and influenced by tumor microenvironment. Carcinoma-associated fibroblasts (CAFs) adapt in a dynamic manner to the metabolic needs of cancer cells, associated with tumorigenesis and resistance to treatments. Importantly, CAFs could directly "feed" cancer cells essential nutrients and energy-rich metabolites, including lactate, ketone bodies, fatty acids, glutamine, and other amino acids through the induction of autophagy in a host-parasite pattern, to contribute to tumor growth and metastasis. To define the reciprocal metabolic interplay between CAFs and cancer cells will provide a better understanding of molecular mechanisms by which the treatment resistance occurs,and aid in the rational design of metabolism-based approaches to enhance the efficacy of immunotherapy.

  2. Nuclear transfer with apoptotic bovine fibroblasts: can programmed cell death be reprogrammed?

    PubMed

    Miranda, Moyses dos Santos; Bressan, Fabiana Fernandes; De Bem, Tiago Henrique Camara; Merighe, Giovana Krempel Fonseca; Ohashi, Otávio Mitio; King, William Alan; Meirelles, Flavio Viera

    2012-06-01

    Cell death by apoptosis is considered to be irreversible. However, reports have indicated that its reversibility is possible if the cells have not yet reached the "point of no return." In order to add new information about this topic, we used cells at different moments of apoptotic process as nuclear donors in somatic cell nuclear transfer (SCNT) in order to test if programmed cell death can be reversed. Adult bovine fibroblasts were treated with 10 μM of staurosporine (STP) for 3 h and analyzed for phosphatidylserine externalization (Annexin assay) and presence of active caspase-9. Annexin-positive (Anx+) and Caspase-9-positive (Casp-9+) cells were isolated by FACS and immediately transferred into enucleated in vitro matured bovine oocytes. After STP treatment, 89.9% of cells were Anx+ (4.6% in control cells; p<0.01) and 24.9% were Casp-9+ (2.4% in control cells; p<0.01). Fusion and cleavage were not affected by the use apoptotic cells (p>0.05). Also, the use of Anx+ cells did not affect blastocyst production compared to control (26.4% vs. 22.9%, respectively; p>0.05). However, blastocyst formation was affected by the use of Casp-9+ cells (12.3%; p<0.05). These findings contribute to the idea of that apoptosis is reversible only at early stages. Additionally, we hypothesize that the "point of no return" for apoptosis may be located around activation of Caspase-9.

  3. A critical role for p38MAPK signalling pathway during reprogramming of human fibroblasts to iPSCs

    PubMed Central

    Neganova, Irina; Chichagova, Valeria; Armstrong, Lyle; Lako, Majlinda

    2017-01-01

    Reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) holds enormous promise for regenerative medicine. Reprogramming is a stepwise process with well-defined stages of initiation, maturation and stabilisation which are critically dependent on interactions between key pluripotency transcription factors, epigenetic regulators and signalling pathways. In this manuscript we have investigated the role of p38 MAPK signalling pathway and have shown a subpopulation- and phase-specific pattern of activation occurring during the initiation and maturation stage of reprogramming in partially and fully reprogrammed cells respectively. Downregulation of p38 MAPK activity via RNA interference or small molecule inhibitor led to cell accumulation in G1 phase of the cell cycle and reduced expression of cell cycle regulators during the initiation stage of reprogramming. This was associated with a significant downregulation of key pluripotency marker expression, disruption of mesenchymal to epithelial transition (MET), increased expression of differentiation markers and presence of partially reprogrammed cells which retained a typical gene expression profile of mesendodermal cells and were unable to progress to fully reprogrammed phenotype. Together our data indicate an important role for p38 MAPK activity in proliferation, MET progression and establishment of pluripotent phenotype, which are necessary steps for the development of human iPSCs. PMID:28155868

  4. MiR-25 Regulates Wwp2 and Fbxw7 and Promotes Reprogramming of Mouse Fibroblast Cells to iPSCs

    PubMed Central

    Lu, Dong; Davis, Matthew P. A.; Abreu-Goodger, Cei; Wang, Wei; Campos, Lia S.; Siede, Julia; Vigorito, Elena; Skarnes, William C.; Dunham, Ian; Enright, Anton J.; Liu, Pentao

    2012-01-01

    Background miRNAs are a class of small non-coding RNAs that regulate gene expression and have critical functions in various biological processes. Hundreds of miRNAs have been identified in mammalian genomes but only a small number of them have been functionally characterized. Recent studies also demonstrate that some miRNAs have important roles in reprogramming somatic cells to induced pluripotent stem cells (iPSCs). Methods We screened 52 miRNAs cloned in a piggybac (PB) vector for their roles in reprogramming of mouse embryonic fibroblast cells to iPSCs. To identify targets of miRNAs, we made Dgcr8-deficient embryonic stem (ES) cells and introduced miRNA mimics to these cells, which lack miRNA biogenesis. The direct target genes of miRNA were identified through global gene expression analysis and target validation. Results and conclusion We found that over-expressing miR-25 or introducing miR-25 mimics enhanced production of iPSCs. We identified a number of miR-25 candidate gene targets. Of particular interest were two ubiquitin ligases, Wwp2 and Fbxw7, which have been proposed to regulate Oct4, c-Myc and Klf5, respectively. Our findings thus highlight the complex interplay between miRNAs and transcription factors involved in reprogramming, stem cell self-renewal and maintenance of pluripotency. PMID:22912667

  5. Activation of Ras in vitro and in intact fibroblasts by the Vav guanine nucleotide exchange protein.

    PubMed Central

    Gulbins, E; Coggeshall, K M; Langlet, C; Baier, G; Bonnefoy-Berard, N; Burn, P; Wittinghofer, A; Katzav, S; Altman, A

    1994-01-01

    We recently identified Vav, the product of the vav proto-oncogene, as a guanine nucleotide exchange factor (GEF) for Ras. Vav is enzymatically activated by lymphocyte antigen receptor-coupled protein tyrosine kinases or independently by diglycerides. To further evaluate the physiological role of Vav, we assessed its GDP-GTP exchange activity against several Ras-related proteins in vitro and determined whether Vav activation in transfected NIH 3T3 fibroblasts correlates with the activity status of Ras and mitogen-activated protein (MAP) kinases. In vitro translated purified Vav activated by phorbol myristate acetate (PMA) or phosphorylation with recombinant p56lck displayed GEF activity against Ras but not against recombinant RacI, RacII, Ral, or RhoA proteins. Expression of vav or proto-vav in stably transfected NIH 3T3 cells led to a approximately 10-fold increase in basal or PMA-stimulated Ras exchange activity, respectively, in total-cell lysates and Vav immunoprecipitates. Elevated GEF activity was paralleled in each case by a significant increase in the proportion of active, GTP-bound Ras. PMA had a minimal effect on the low Ras. GTP level in untransfected control fibroblasts but increased it from 20 to 37% in proto-vav-transfected cells. vav-transfected cells displayed a constitutively elevated Ras. GTP level (35%), which was not increased further by PMA treatment. MAP kinases, known downstream intermediates in Ras-dependent signaling pathways, similarly exhibited increased basal or PMA-stimulated activity in Vav-expressing cells by comparison with normal NIH 3T3 cells. These results demonstrate a physiologic interaction between Vav and its target, Ras, leading to MAP kinase activation. Images PMID:8289830

  6. Expression of Six Proteins Causes Reprogramming of Porcine Fibroblasts Into Induced Pluripotent Stem Cells With Both Active X Chromosomes.

    PubMed

    Fukuda, Tomokazu; Tani, Tetsuya; Haraguchi, Seiki; Donai, Kenichiro; Nakajima, Nobuyoshi; Uenishi, Hirohide; Eitsuka, Takahiro; Miyagawa, Makoto; Song, Sanghoun; Onuma, Manabu; Hoshino, Yumi; Sato, Eimei; Honda, Arata

    2017-03-01

    In this study, we created porcine-induced pluripotent stem (iPS) cells with the expression of six reprogramming factors (Oct3/4, Klf4, Sox2, c-Myc, Lin28, and Nanog). The resulting cells showed growth dependent on LIF (leukemia inhibitory factor) and expression of multiple stem cell markers. Furthermore, the iPS cells caused teratoma formation with three layers of differentiation and had both active X chromosomes (XaXa). Our iPS cells satisfied the both of important characteristics of stem cells: teratoma formation and activation of both X chromosomes. Injection of these iPS cells into morula stage embryos showed that these cells participate in the early stage of porcine embryogenesis. Furthermore, the RNA-Seq analysis detected that expression levels of endogenous pluripotent related genes, NANOG, SOX2, ZFP42, OCT3/4, ESRRB, and ERAS were much higher in iPS with six factors than that with four reprogramming factors. We can conclude that the expression of six reprogramming factors enables the creation of porcine iPS cells, which is partially close to naive iPS state. J. Cell. Biochem. 118: 537-553, 2017. © 2016 Wiley Periodicals, Inc.

  7. Reprogramming of fibroblast nuclei in cloned bovine embryos involves major structural remodeling with both striking similarities and differences to nuclear phenotypes of in vitro fertilized embryos.

    PubMed

    Popken, Jens; Brero, Alessandro; Koehler, Daniela; Schmid, Volker J; Strauss, Axel; Wuensch, Annegret; Guengoer, Tuna; Graf, Alexander; Krebs, Stefan; Blum, Helmut; Zakhartchenko, Valeri; Wolf, Eckhard; Cremer, Thomas

    2014-01-01

    Nuclear landscapes were studied during preimplantation development of bovine embryos, generated either by in vitro fertilization (IVF), or generated as cloned embryos by somatic cell nuclear transfer (SCNT) of bovine fetal fibroblasts, using 3-dimensional confocal laser scanning microscopy (3D-CLSM) and structured illumination microscopy (3D-SIM). Nuclear landscapes of IVF and SCNT embryonic nuclei were compared with each other and with fibroblast nuclei. We demonstrate that reprogramming of fibroblast nuclei in cloned embryos requires changes of their landscapes similar to nuclei of IVF embryos. On the way toward the 8-cell stage, where major genome activation occurs, a major lacuna, enriched with splicing factors, was formed in the nuclear interior and chromosome territories (CTs) were shifted toward the nuclear periphery. During further development the major lacuna disappeared and CTs were redistributed throughout the nuclear interior forming a contiguous higher order chromatin network. At all stages of development CTs of IVF and SCNT embryonic nuclei were built up from chromatin domain clusters (CDCs) pervaded by interchromatin compartment (IC) channels. Quantitative analyses revealed a highly significant enrichment of RNA polymerase II and H3K4me3, a marker for transcriptionally competent chromatin, at the periphery of CDCs. In contrast, H3K9me3, a marker for silent chromatin, was enriched in the more compacted interior of CDCs. Despite these striking similarities, we also detected major differences between nuclear landscapes of IVF and cloned embryos. Possible implications of these differences for the developmental potential of cloned animals remain to be investigated. We present a model, which integrates generally applicable structural and functional features of the nuclear landscape.

  8. Reprogramming of fibroblast nuclei in cloned bovine embryos involves major structural remodeling with both striking similarities and differences to nuclear phenotypes of in vitro fertilized embryos

    PubMed Central

    Popken, Jens; Brero, Alessandro; Koehler, Daniela; Schmid, Volker J; Strauss, Axel; Wuensch, Annegret; Guengoer, Tuna; Graf, Alexander; Krebs, Stefan; Blum, Helmut; Zakhartchenko, Valeri; Wolf, Eckhard; Cremer, Thomas

    2014-01-01

    Nuclear landscapes were studied during preimplantation development of bovine embryos, generated either by in vitro fertilization (IVF), or generated as cloned embryos by somatic cell nuclear transfer (SCNT) of bovine fetal fibroblasts, using 3-dimensional confocal laser scanning microscopy (3D-CLSM) and structured illumination microscopy (3D-SIM). Nuclear landscapes of IVF and SCNT embryonic nuclei were compared with each other and with fibroblast nuclei. We demonstrate that reprogramming of fibroblast nuclei in cloned embryos requires changes of their landscapes similar to nuclei of IVF embryos. On the way toward the 8-cell stage, where major genome activation occurs, a major lacuna, enriched with splicing factors, was formed in the nuclear interior and chromosome territories (CTs) were shifted toward the nuclear periphery. During further development the major lacuna disappeared and CTs were redistributed throughout the nuclear interior forming a contiguous higher order chromatin network. At all stages of development CTs of IVF and SCNT embryonic nuclei were built up from chromatin domain clusters (CDCs) pervaded by interchromatin compartment (IC) channels. Quantitative analyses revealed a highly significant enrichment of RNA polymerase II and H3K4me3, a marker for transcriptionally competent chromatin, at the periphery of CDCs. In contrast, H3K9me3, a marker for silent chromatin, was enriched in the more compacted interior of CDCs. Despite these striking similarities, we also detected major differences between nuclear landscapes of IVF and cloned embryos. Possible implications of these differences for the developmental potential of cloned animals remain to be investigated. We present a model, which integrates generally applicable structural and functional features of the nuclear landscape. PMID:25482066

  9. Metabolic reprogramming of cancer-associated fibroblasts by TGF-β drives tumor growth: connecting TGF-β signaling with "Warburg-like" cancer metabolism and L-lactate production.

    PubMed

    Guido, Carmela; Whitaker-Menezes, Diana; Capparelli, Claudia; Balliet, Renee; Lin, Zhao; Pestell, Richard G; Howell, Anthony; Aquila, Saveria; Andò, Sebastiano; Martinez-Outschoorn, Ubaldo; Sotgia, Federica; Lisanti, Michael P

    2012-08-15

    We have previously shown that a loss of stromal Cav-1 is a biomarker of poor prognosis in breast cancers. Mechanistically, a loss of Cav-1 induces the metabolic reprogramming of stromal cells, with increased autophagy/mitophagy, mitochondrial dysfunction and aerobic glycolysis. As a consequence, Cav-1-low CAFs generate nutrients (such as L-lactate) and chemical building blocks that fuel mitochondrial metabolism and the anabolic growth of adjacent breast cancer cells. It is also known that a loss of Cav-1 is associated with hyperactive TGF-β signaling. However, it remains unknown whether hyperactivation of the TGF-β signaling pathway contributes to the metabolic reprogramming of Cav-1-low CAFs. To address these issues, we overexpressed TGF-β ligands and the TGF-β receptor I (TGFβ-RI) in stromal fibroblasts and breast cancer cells. Here, we show that the role of TGF-β in tumorigenesis is compartment-specific, and that TGF-β promotes tumorigenesis by shifting cancer-associated fibroblasts toward catabolic metabolism. Importantly, the tumor-promoting effects of TGF-β are independent of the cell type generating TGF-β. Thus, stromal-derived TGF-β activates signaling in stromal cells in an autocrine fashion, leading to fibroblast activation, as judged by increased expression of myofibroblast markers, and metabolic reprogramming, with a shift toward catabolic metabolism and oxidative stress. We also show that TGF-β-activated fibroblasts promote the mitochondrial activity of adjacent cancer cells, and in a xenograft model, enhancing the growth of breast cancer cells, independently of angiogenesis. Conversely, activation of the TGF-β pathway in cancer cells does not influence tumor growth, but cancer cell-derived-TGF-β ligands affect stromal cells in a paracrine fashion, leading to fibroblast activation and enhanced tumor growth. In conclusion, ligand-dependent or cell-autonomous activation of the TGF-β pathway in stromal cells induces their metabolic

  10. Reprogramming fibroblasts to pluripotency using arginine-terminated polyamidoamine nanoparticles based non-viral gene delivery system

    PubMed Central

    Zhu, Kai; Li, Jun; Lai, Hao; Yang, Cheng; Guo, Changfa; Wang, Chunsheng

    2014-01-01

    Induced pluripotent stem cells (iPSCs) have attracted keen interest in regenerative medicine. The generation of iPSCs from somatic cells can be achieved by the delivery of defined transcription factor (Oct4, Sox2, Klf4, and c-Myc[OSKM]). However, most instances of iPSC-generation have been achieved by potentially harmful genome-integrating viral vectors. Here we report the generation of iPSCs from mouse embryonic fibroblasts (MEFs) using arginine-terminated generation 4 polyamidoamine (G4Arg) nanoparticles as a nonviral transfection vector for the delivery of a single plasmid construct carrying OSKM (pOSKM). Our results showed that G4Arg nanoparticles delivered pOSKM into MEFs at a significantly higher transfection efficiency than did conventional transfection reagents. After serial transfections of pOSKM-encapsulated G4Arg nanoparticles, we successfully generated iPSCs from MEFs. Our study demonstrates that G4Arg nanoparticles may be a promising candidate for generating of virus-free iPSCs that have great potential for clinical application. PMID:25540584

  11. Nuclear reprogramming.

    PubMed

    Halley-Stott, Richard P; Pasque, Vincent; Gurdon, J B

    2013-06-01

    There is currently particular interest in the field of nuclear reprogramming, a process by which the identity of specialised cells may be changed, typically to an embryonic-like state. Reprogramming procedures provide insight into many mechanisms of fundamental cell biology and have several promising applications, most notably in healthcare through the development of human disease models and patient-specific tissue-replacement therapies. Here, we introduce the field of nuclear reprogramming and briefly discuss six of the procedures by which reprogramming may be experimentally performed: nuclear transfer to eggs or oocytes, cell fusion, extract treatment, direct reprogramming to pluripotency and transdifferentiation.

  12. Discovery and progress of direct cardiac reprogramming.

    PubMed

    Kojima, Hidenori; Ieda, Masaki

    2017-02-14

    Cardiac disease remains a major cause of death worldwide. Direct cardiac reprogramming has emerged as a promising approach for cardiac regenerative therapy. After the discovery of MyoD, a master regulator for skeletal muscle, other single cardiac reprogramming factors (master regulators) have been sought. Discovery of cardiac reprogramming factors was inspired by the finding that multiple, but not single, transcription factors were needed to generate induced pluripotent stem cells (iPSCs) from fibroblasts. We first reported a combination of cardiac-specific transcription factors, Gata4, Mef2c, and Tbx5 (GMT), that could convert mouse fibroblasts into cardiomyocyte-like cells, which were designated as induced cardiomyocyte-like cells (iCMs). Following our first report of cardiac reprogramming, many researchers, including ourselves, demonstrated an improvement in cardiac reprogramming efficiency, in vivo direct cardiac reprogramming for heart regeneration, and cardiac reprogramming in human cells. However, cardiac reprogramming in human cells and adult fibroblasts remains inefficient, and further efforts are needed. We believe that future research elucidating epigenetic barriers and molecular mechanisms of direct cardiac reprogramming will improve the reprogramming efficiency, and that this new technology has great potential for clinical applications.

  13. Connective tissue growth factor/CCN2-null mouse embryonic fibroblasts retain intact transforming growth factor-{beta} responsiveness

    SciTech Connect

    Mori, Yasuji; Hinchcliff, Monique; Wu, Minghua; Warner-Blankenship, Matthew; Lyons, Karen M.

    2008-03-10

    Background: The matricellular protein connective tissue growth factor (CCN2) has been implicated in pathological fibrosis, but its physiologic role remains elusive. In vitro, transforming growth factor-{beta} (TGF-{beta}) induces CCN2 expression in mesenchymal cells. Because CCN2 can enhance profibrotic responses elicited by TGF-{beta}, it has been proposed that CCN2 functions as an essential downstream signaling mediator for TGF-{beta}. To explore this notion, we characterized TGF-{beta}-induced activation of fibroblasts from CCN2-null (CCN2{sup -/-}) mouse embryos. Methods: The regulation of CCN2 expression was examined in vivo in a model of fibrosis induced by bleomycin. Cellular TGF-{beta} signal transduction and regulation of collagen gene expression were examined in CCN2{sup -/-} MEFs by immunohistochemistry, Northern, Western and RT-PCR analysis, immunocytochemistry and transient transfection assays. Results: Bleomycin-induced skin fibrosis in the mouse was associated with substantial CCN2 up-regulation in lesional fibroblasts. Whereas in vitro proliferation rate of CCN2{sup -/-} MEFs was markedly reduced compared to wild type MEFs, TGF-{beta}-induced activation of the Smad pathways, including Smad2 phosphorylation, Smad2/3 and Smad4 nuclear accumulation and Smad-dependent transcriptional responses, were unaffected by loss of CCN2. The stimulation of COL1A2 and fibronectin mRNA expression and promoter activity, and of corresponding protein levels, showed comparable time and dose-response in wild type and CCN2{sup -/-} MEFs, whereas stimulation of alpha smooth muscle actin and myofibroblast transdifferentiation showed subtle impairment in MEFs lacking CCN2. Conclusion: Whereas endogenous CCN2 plays a role in regulation of proliferation and TGF-{beta}-induced myofibroblast transdifferentiation, it appears to be dispensable for Smad-dependent stimulation of collagen and extracellular matrix synthesis in murine embryonic fibroblasts.

  14. Association of serum intact fibroblast growth factor 23 with left ventricular mass and different echocardiographic findings in patients on hemodialysis

    PubMed Central

    Nassiri, Amir Ahmad; Safar-Pour, Reza; Ahmadi, Ali; Tohidi, Maryam; Kashani, Babak Sharif; Esfehani, Fatemeh; Alatab, Soudabeh

    2016-01-01

    Abstract Objectives To determine the association of fibroblast growth factor 23 (FGF23) with left ventricular hypertrophy (LVH) through the assessment of left ventricular (LV) mass and left ventricular mass index (LVMI) in patients on hemodialysis, this study was done. Methods All patients on hemodialysis who are older than 18 years and in whom hemodialysis vintage was at least 6 months were enrolled. All patients were on hemodialysis thrice a week for 4 h using low-flux dialysis filters, polysulfone membranes, reverse osmosis purified water, and bicarbonate-base hemodialysis solution. The exclusion criteria were any respiratory illness or pulmonary infection, cigarette smoking, and the presence of pericarditis or pericardial effusion. Additionally, patients with a known coronary artery disease, any form of cardiac arrhythmias, any cardiomyopathy or severe valvular heart disease diagnosed by echocardiography, acute congestive heart failure (CHF), and acute myocardial infarction were not included. Echocardiography was conducted by an experienced operator for all the enrolled patients using the ACUSON SC2000™ ultrasound system transducer (Siemens), with a frequency bandwidth of: 1.5–3.5 MHz. Patients were considered to have LVH if the LVMI was greater than 134 g/m2 for men and greater than 110 g/m2 for women. Results A total of 61 patients (19 female and 42 male) were enrolled to the study. Mean (± SD) age of the patients was 59.6 ± 13.1 years. The median duration of hemodialysis was 23 (range: 6–120) months. The median predialysis level of FGF23 was 1,977 pg/mL (range: 155–8,870). LVH was seen in 73.8% of the patients (n = 45) and of them 66.7% were male. There was a statistically significant direct correlation between FGF23 and left ventricle diameter in end systole (LVDs) (r = 0.29, P = 0.027). However, the association of FGF23 with LV mass, LVMI, and left ventricular ejection fraction (LVEF) was not significant. Conclusion This study does not show the

  15. Dynamic culture improves cell reprogramming efficiency.

    PubMed

    Sia, Junren; Sun, Raymond; Chu, Julia; Li, Song

    2016-06-01

    Cell reprogramming to pluripotency is an inefficient process and various approaches have been devised to improve the yield of induced pluripotent stem cells. However, the effect of biophysical factors on cell reprogramming is not well understood. Here we showed that, for the first time, dynamic culture with orbital shaking significantly improved the reprogramming efficiency in adherent cells. Manipulating the viscosity of the culture medium suggested that the improved efficiency is mainly attributed to convective mixing rather than hydrodynamic shear stress. Temporal studies demonstrated that the enhancement of reprogramming efficiency required the dynamic culture in the middle but not early phase. In the early phase, fibroblasts had a high proliferation rate, but as the culture became over-confluent in the middle phase, expression of p57 was upregulated to inhibit cell proliferation and consequently, cell reprogramming. Subjecting the over confluent culture to orbital shaking prevented the upregulation of p57, thus improving reprogramming efficiency. Seeding cells at low densities to avoid over-confluency resulted in a lower efficiency, and optimal reprogramming efficiency was attained at a high seeding density with dynamic culture. Our findings provide insight into the underlying mechanisms of how dynamic culture condition regulate cell reprogramming, and will have broad impact on cell engineering for regenerative medicine and disease modeling.

  16. Loss of miR-140 is a key risk factor for radiation-induced lung fibrosis through reprogramming fibroblasts and macrophages

    PubMed Central

    Duru, Nadire; Zhang, Yongshu; Gernapudi, Ramkishore; Wolfson, Benjamin; Lo, Pang-Kuo; Yao, Yuan; Zhou, Qun

    2016-01-01

    Radiation-induced lung fibrosis (RILF) is a common side effect for patients with thoracic cancer receiving radiation therapy. RILF is characterized by excessive collagen deposition mediated by TGF-β1 and its downstream factor SMAD3, but the exact molecular mechanism leading to fibrosis is yet to be determined. The present study investigated the impact of miR-140 on RILF development. Herein, we first found that loss of miR-140 is a marker of fibrotic lung tissue in vivo one-year post-radiation treatment. We showed that miR-140 knockout primary lung fibroblasts have a higher percentage of myofibroblasts compared to wild type primary lung fibroblasts, and that loss of miR-140 expression leads to increased activation of TGF-β1 signaling as well as increased myofibroblast differentiation. We also identified fibronectin as a novel miR-140 target gene in lung fibroblasts. Finally, we have shown that miR-140 deficiency promotes accumulation of M2 macrophages in irradiated lung tissues. These data suggest that miR-140 is a key protective molecule against RILF through inhibiting myofibroblast differentiation and inflammation. PMID:27996039

  17. Pluripotent reprogramming and lineage reprogramming: promises and challenges in cardiovascular regeneration.

    PubMed

    He, Wen-Jun; Hou, Qian; Han, Qing-Wang; Han, Wei-Dong; Fu, Xiao-Bing

    2014-08-01

    Cardiovascular disease is a leading cause of death in industrialized countries. Scientists are trying to generate cardiomyocytes in vitro and in vivo to repair damaged heart tissue. Pluripotent reprogramming brings an alternative source of embryonic-like stem cells, and the possibility of regenerating mammalian tissues by first reverting somatic cells to induced pluripotent stem cells, followed by redifferentiating these cells into cardiomyocytes. More recently, lineage reprogramming of fibroblasts directly into functional cardiomyocytes has been reported. The procedure does not involve reverting cells back to a pluripotent stage, and, thus, would presumably reduce tumorigenic potential. Interestingly, lineage reprogramming could be used for in situ conversion of cell fate. Moreover, zebrafish-like regenerative mechanism in mammalian heart tissue, which was observed in mice within the first week of postpartum, should be further addressed. Here, we review the landmark progresses of the two major reprogramming strategies, compare their pros and cons in cardiovascular regeneration, and forecast the future directions of cardiac repair.

  18. Defining the Diversity of Phenotypic Respecification Using Multiple Cell Lines and Reprogramming Regimens

    PubMed Central

    Alicea, Bradly; Murthy, Shashanka; Keaton, Sarah A.; Cobbett, Peter; Cibelli, Jose B.

    2013-01-01

    To better understand the basis of variation in cellular reprogramming, we performed experiments with two primary objectives: first, to determine the degree of difference, if any, in reprogramming efficiency among cells lines of a similar type after accounting for technical variables, and second, to compare the efficiency of conversion of multiple similar cell lines to two separate reprogramming regimens–induced neurons and induced skeletal muscle. Using two reprogramming regimens, it could be determined whether converted cells are likely derived from a distinct subpopulation that is generally susceptible to reprogramming or are derived from cells with an independent capacity for respecification to a given phenotype. Our results indicated that when technical components of the reprogramming regimen were accounted for, reprogramming efficiency was reproducible within a given primary fibroblast line but varied dramatically between lines. The disparity in reprogramming efficiency between lines was of sufficient magnitude to account for some discrepancies in published results. We also found that the efficiency of conversion to one phenotype was not predictive of reprogramming to the alternate phenotype, suggesting that the capacity for reprogramming does not arise from a specific subpopulation with a generally “weak grip” on cellular identity. Our findings suggest that parallel testing of multiple cell lines from several sources may be needed to accurately assess the efficiency of direct reprogramming procedures, and that testing a larger number of fibroblast lines—even lines with similar origins—is likely the most direct means of improving reprogramming efficiency. PMID:23672680

  19. Rejuvenation by partial reprogramming of the epigenome.

    PubMed

    Mendelsohn, Andrew R; Larrick, James; Lei, Jennifer L

    2017-03-17

    Epigenetic variation with age is one of the most important hallmarks of aging. Resetting or repairing the epigenome of aging cells in intact animals may rejuvenate the cells and perhaps the entire organism. In fact, differentiated adult cells, which by definition have undergone some epigenetic changes, are capable of being rejuvenated and reprogrammed to create pluripotent stem cells and viable cloned animals. Apparently, such reprogramming is capable of completely resetting the epigenome. However, attempts to fully reprogram differentiated cells in adult animals have failed in part because reprogramming leads to formation of teratomas. A preliminary method to partially reprogram adult cells in mature Hutchinson-Guilford progeria (HGPS) mice by transient induction of the Yamanaka factors OSKM(Oct4/Sox2/Klf4/c-Myc) appears to ameliorate aging-like phenotypes in HGPS mice, and promote youthful regenerative capability in middle-aged wild type individuals exposed to beta cell and muscle cell specific toxins. However, whatever epigenetic repair is induced by transient reprogramming does not endure and may be due to the induction of key homeostatic regulators instead. Some of the effect of transient reprogramming may result from increased proliferation and enhanced function of adult stem cells. Partial reprogramming may point the way to new anti-aging and pro-regenerative therapeutics. Redifferentiation of cells into their pre-existing phenotype with simultaneous epigenomic rejuvenation is an interesting variation that also should be pursued. However, discovery of methods to more precisely repair the epigenome is the most likely avenue to the development of powerful new anti-aging agents.

  20. Optimal ROS Signaling Is Critical for Nuclear Reprogramming.

    PubMed

    Zhou, Gang; Meng, Shu; Li, Yanhui; Ghebre, Yohannes T; Cooke, John P

    2016-05-03

    Efficient nuclear reprogramming of somatic cells to pluripotency requires activation of innate immunity. Because innate immune activation triggers reactive oxygen species (ROS) signaling, we sought to determine whether there was a role of ROS signaling in nuclear reprogramming. We examined ROS production during the reprogramming of doxycycline (dox)-inducible mouse embryonic fibroblasts (MEFs) carrying the Yamanaka factors (Oct4, Sox2, Klf4, and c-Myc [OSKM]) into induced pluripotent stem cells (iPSCs). ROS generation was substantially increased with the onset of reprogramming. Depletion of ROS via antioxidants or Nox inhibitors substantially decreased reprogramming efficiency. Similarly, both knockdown and knockout of p22(phox)-a critical subunit of the Nox (1-4) complex-decreased reprogramming efficiency. However, excessive ROS generation using genetic and pharmacological approaches also impaired reprogramming. Overall, our data indicate that ROS signaling is activated early with nuclear reprogramming, and optimal levels of ROS signaling are essential to induce pluripotency.

  1. Early reprogramming regulators identified by prospective isolation and mass cytometry

    PubMed Central

    Lujan, Ernesto; Zunder, Eli R.; Ng, Yi Han; Goronzy, Isabel N.; Nolan, Garry P.; Wernig, Marius

    2015-01-01

    In the context of most induced pluripotent stem (iPS) cell reprogramming methods, heterogeneous populations of nonproductive and staggered productive intermediates arise at different reprogramming time points1–11. Despite recent reports claiming substantially increased reprogramming efficiencies using genetically modified donor cells12,13 prospectively isolating distinct reprogramming intermediates remains an important goal to decipher reprogramming mechanisms. Previous attempts to identify surface markers of intermediate cell populations were based on the assumption that during reprogramming cells progressively lose donor cell identity and gradually acquire iPS cell properties1,2,7,8,10. Here, we report that iPS cell and epithelial markers, such as SSEA1 and EpCAM, respectively, are not predictive of reprogramming during early phases. Instead, in a systematic functional surface marker screen we find that early reprogramming-prone cells express a unique set of surface markers, including CD73, CD49d and CD200 that are absent in fibroblasts and iPS cells. Single cell mass cytometry and prospective isolation show that these distinct intermediates are transient and bridge the gap between donor cell silencing and pluripotency marker acquisition during the early, presumably stochastic reprogramming phase2. Expression profiling revealed early upregulation of the transcriptional regulators Nr0b1 and Etv5 in this reprogramming state, preceding activation of key pluripotency regulators such as Rex1, Dppa2, Nanog and Sox2. Both factors are required for the generation of the early intermediate state and fully reprogrammed iPS cells, and thus mark some of the earliest known regulators of iPS cell induction. Our study deconvolutes the first steps in a hierarchical series of events that lead to pluripotency acquisition. PMID:25830878

  2. MicroRNA-mediated somatic cell reprogramming.

    PubMed

    Kuo, Chih-Hao; Ying, Shao-Yao

    2013-02-01

    Since the first report of induced pluripotent stem cells (iPSCs) using somatic cell nuclear transfer (SCNT), much focus has been placed on iPSCs due to their great therapeutic potential for diseases such as abnormal development, degenerative disorders, and even cancers. Subsequently, Takahashi and Yamanaka took a novel approach by using four defined transcription factors to generate iPSCs in mice and human fibroblast cells. Scientists have since been trying to refine or develop better approaches to reprogramming, either by using different combinations of transcription factors or delivery methods. However, recent reports showed that the microRNA expression pattern plays a crucial role in somatic cell reprogramming and ectopic introduction of embryonic stem cell-specific microRNAs revert cells back to an ESC-like state, although, the exact mechanism underlying this effect remains unclear. This review describes recent work that has focused on microRNA-mediated approaches to somatic cell reprogramming as well as some of the pros and cons to these approaches and a possible mechanism of action. Based on the pivotal role of microRNAs in embryogenesis and somatic cell reprogramming, studies in this area must continue in order to gain a better understanding of the role of microRNAs in stem cells regulation and activity.

  3. Lineage Reprogramming: A Promising Road for Pancreatic β Cell Regeneration.

    PubMed

    Wei, Rui; Hong, Tianpei

    2016-03-01

    Cell replacement therapy is a promising method to restore pancreatic β cell function and cure diabetes. Distantly related cells (fibroblasts, keratinocytes, and muscle cells) and developmentally related cells (hepatocytes, gastrointestinal, and pancreatic exocrine cells) have been successfully reprogrammed into β cells in vitro and in vivo. However, while some reprogrammed β cells bear similarities to bona fide β cells, others do not develop into fully functional β cells. Here we review various strategies currently used for β cell reprogramming, including ectopic expression of specific transcription factors associated with islet development, repression of maintenance factors of host cells, regulation of epigenetic modifications, and microenvironmental changes. Development of simple and efficient reprogramming methods is a key priority for developing fully functional β cells suitable for cell replacement therapy.

  4. Reprogramming mammalian somatic cells.

    PubMed

    Rodriguez-Osorio, N; Urrego, R; Cibelli, J B; Eilertsen, K; Memili, E

    2012-12-01

    Somatic cell nuclear transfer (SCNT), the technique commonly known as cloning, permits transformation of a somatic cell into an undifferentiated zygote with the potential to develop into a newborn animal (i.e., a clone). In somatic cells, chromatin is programmed to repress most genes and express some, depending on the tissue. It is evident that the enucleated oocyte provides the environment in which embryonic genes in a somatic cell can be expressed. This process is controlled by a series of epigenetic modifications, generally referred to as "nuclear reprogramming," which are thought to involve the removal of reversible epigenetic changes acquired during cell differentiation. A similar process is thought to occur by overexpression of key transcription factors to generate induced pluripotent stem cells (iPSCs), bypassing the need for SCNT. Despite its obvious scientific and medical importance, and the great number of studies addressing the subject, the molecular basis of reprogramming in both reprogramming strategies is largely unknown. The present review focuses on the cellular and molecular events that occur during nuclear reprogramming in the context of SCNT and the various approaches currently being used to improve nuclear reprogramming. A better understanding of the reprogramming mechanism will have a direct impact on the efficiency of current SCNT procedures, as well as iPSC derivation.

  5. In vivo myomaker-mediated heterologous fusion and nuclear reprogramming.

    PubMed

    Mitani, Yasuyuki; Vagnozzi, Ronald J; Millay, Douglas P

    2017-01-01

    Knowledge regarding cellular fusion and nuclear reprogramming may aid in cell therapy strategies for skeletal muscle diseases. An issue with cell therapy approaches to restore dystrophin expression in muscular dystrophy is obtaining a sufficient quantity of cells that normally fuse with muscle. Here we conferred fusogenic activity without transdifferentiation to multiple non-muscle cell types and tested dystrophin restoration in mouse models of muscular dystrophy. We previously demonstrated that myomaker, a skeletal muscle-specific transmembrane protein necessary for myoblast fusion, is sufficient to fuse 10T 1/2 fibroblasts to myoblasts in vitro. Whether myomaker-mediated heterologous fusion is functional in vivo and whether the newly introduced nonmuscle nuclei undergoes nuclear reprogramming has not been investigated. We showed that mesenchymal stromal cells, cortical bone stem cells, and tail-tip fibroblasts fuse to skeletal muscle when they express myomaker. These cells restored dystrophin expression in a fraction of dystrophin-deficient myotubes after fusion in vitro. However, dystrophin restoration was not detected in vivo although nuclear reprogramming of the muscle-specific myosin light chain promoter did occur. Despite the lack of detectable dystrophin reprogramming by immunostaining, this study indicated that myomaker could be used in nonmuscle cells to induce fusion with muscle in vivo, thereby providing a platform to deliver therapeutic material.-Mitani, Y., Vagnozzi, R. J., Millay, D. P. In vivo myomaker-mediated heterologous fusion and nuclear reprogramming.

  6. Concise review: reprogramming strategies for cardiovascular regenerative medicine: from induced pluripotent stem cells to direct reprogramming.

    PubMed

    Budniatzky, Inbar; Gepstein, Lior

    2014-04-01

    Myocardial cell-replacement therapies are emerging as novel therapeutic paradigms for myocardial repair but are hampered by the lack of sources of autologous human cardiomyocytes. The recent advances in stem cell biology and in transcription factor-based reprogramming strategies may provide exciting solutions to this problem. In the current review, we describe the different reprogramming strategies that can give rise to cardiomyocytes for regenerative medicine purposes. Initially, we describe induced pluripotent stem cell technology, a method by which adult somatic cells can be reprogrammed to yield pluripotent stem cells that could later be coaxed ex vivo to differentiate into cardiomyocytes. The generated induced pluripotent stem cell-derived cardiomyocytes could then be used for myocardial cell transplantation and tissue engineering strategies. We also describe the more recent direct reprogramming approaches that aim to directly convert the phenotype of one mature cell type (fibroblast) to another (cardiomyocyte) without going through a pluripotent intermediate cell type. The advantages and shortcomings of each strategy for cardiac regeneration are discussed, along with the hurdles that need to be overcome on the road to clinical translation.

  7. FoxO3 regulates neuronal reprogramming of cells from postnatal and aging mice

    PubMed Central

    Ahlenius, Henrik; Chanda, Soham; Webb, Ashley E.; Yousif, Issa; Karmazin, Jesse; Prusiner, Stanley B.; Brunet, Anne; Südhof, Thomas C.; Wernig, Marius

    2016-01-01

    We and others have shown that embryonic and neonatal fibroblasts can be directly converted into induced neuronal (iN) cells with mature functional properties. Reprogramming of fibroblasts from adult and aged mice, however, has not yet been explored in detail. The ability to generate fully functional iN cells from aged organisms will be particularly important for in vitro modeling of diseases of old age. Here, we demonstrate production of functional iN cells from fibroblasts that were derived from mice close to the end of their lifespan. iN cells from aged mice had apparently normal active and passive neuronal membrane properties and formed abundant synaptic connections. The reprogramming efficiency gradually decreased with fibroblasts derived from embryonic and neonatal mice, but remained similar for fibroblasts from postnatal mice of all ages. Strikingly, overexpression of a transcription factor, forkhead box O3 (FoxO3), which is implicated in aging, blocked iN cell conversion of embryonic fibroblasts, whereas knockout or knockdown of FoxO3 increased the reprogramming efficiency of adult-derived but not of embryonic fibroblasts and also enhanced functional maturation of resulting iN cells. Hence, FoxO3 has a central role in the neuronal reprogramming susceptibility of cells, and the importance of FoxO3 appears to change during development. PMID:27402759

  8. Video: reprogramming cells.

    PubMed

    2008-12-19

    This video introduction to Science's year-end special issue features Shinya Yamanaka of Kyoto University, George Daley of Harvard University, and Science's Gretchen Vogel reviewing some of the work that led studies in reprogramming cells to be tagged the top scientific story for 2008.

  9. [Reprogramming of somatic cells. Problems and solutions].

    PubMed

    Schneider, T A; Fishman, V S; Liskovykh, M A; Ponamartsev, S V; Serov, O L; Tomilin, A N; Alenina, N

    2014-01-01

    An adult mammal is composed of more than 200 different types of specialized somatic cells whose differentiated state remains stable over the life of the organism. For a long time it was believed that the differentiation process is irreversible, and the transition between the two types of specialized cells is impossible. The possibility of direct conversion of one differentiated cell type to another was first shown in the 80s of the last century in experiments on the conversion of fibroblasts into myoblasts by ectopic expression of the transcription factor MyoD. Surprisingly, this technology has remained unclaimed in cell biology for a long time. Interest in it revived after 200 thanks to the research of Novel Prize winner Shinya Yamanaka who has shown that a small set of transcription factors (Oct4, Sox2, Klf4 and c-Myc) is capable of restoring pluripotency in somatic cells which they lost in the process of differentiation. In 2010, using a similar strategy and the tissue-specific transcription factors Vierbuchen and coauthors showed the possibility of direct conversion of fibroblasts into neurons, i. e. the possibility of transdifferentiation of one type of somatic cells in the other. The works of these authoras were a breakthrough in the field of cell biology and gave a powerful impulse to the development of cell technologies for the needs of regenerative medicine. The present review discusses the main historical discoveries that preceded this work, evaluates the status of the problem and the progress in the development of methods for reprogramming at the moment, describes the main approaches to solving the problems of reprogramming of somatic cells into neuronal, and briefly discusses the prospect of application of reprogramming and transdifferentiation of cells for such important application areas as regenerative medicine, cell replacement therapy and drug screening.

  10. Reprogramming of Somatic Cells Towards Pluripotency by Cell Fusion.

    PubMed

    Malinowski, Andrzej R; Fisher, Amanda G

    2016-01-01

    Pluripotent reprogramming can be dominantly induced in a somatic nucleus upon fusion with a pluripotent cell such as embryonic stem (ES) cell. Cell fusion between ES cells and somatic cells results in the formation of heterokaryons, in which the somatic nuclei begin to acquire features of the pluripotent partner. The generation of interspecies heterokaryons between mouse ES- and human somatic cells allows an experimenter to distinguish the nuclear events occurring specifically within the reprogrammed nucleus. Therefore, cell fusion provides a simple and rapid approach to look at the early nuclear events underlying pluripotent reprogramming. Here, we describe a polyethylene glycol (PEG)-mediated cell fusion protocol to generate interspecies heterokaryons and intraspecies hybrids between ES cells and B lymphocytes or fibroblasts.

  11. Reprogramming aging and progeria.

    PubMed

    Freije, José M P; López-Otín, Carlos

    2012-12-01

    The aging rate of an organism depends on the ratio of tissue degeneration to tissue repair. As a consequence, molecular alterations that tip this balance toward degeneration cause accelerated aging. Conversely, interventions can be pursued to reduce tissue degeneration or to increase tissue repair with the aim of delaying the onset of age-associated manifestations. Recent studies on the biology of stem cells in aging have revealed the influence of systemic factors on their functionality and demonstrated the feasibility of reprogramming aged and progeroid cells. These results illustrate the reversibility of some aspects of the aging process and encourage the search for new anti-aging and anti-progeria interventions.

  12. Generation of iPSC line HEL24.3 from human neonatal foreskin fibroblasts.

    PubMed

    Trokovic, Ras; Weltner, Jere; Otonkoski, Timo

    2015-07-01

    Human iPSC line HEL24.3 was generated from healthy human foreskin fibroblasts using non-integrative reprogramming method. Reprogramming factors Oct3/4, Sox2, Klf4, and cMyc were delivered using Sendai viruses.

  13. Forward engineering neuronal diversity using direct reprogramming.

    PubMed

    Tsunemoto, Rachel K; Eade, Kevin T; Blanchard, Joel W; Baldwin, Kristin K

    2015-06-03

    The nervous system is comprised of a vast diversity of distinct neural cell types. Differences between neuronal subtypes drive the assembly of neuronal circuits and underlie the subtype specificity of many neurological diseases. Yet, because neurons are irreversibly post-mitotic and not readily available from patients, it has not been feasible to study specific subtypes of human neurons in larger numbers. A powerful means to study neuronal diversity and neurological disease is to establish methods to produce desired neuronal subtypes in vitro. Traditionally this has been accomplished by treating pluripotent or neural stem cells with growth factors and morphogens that recapitulate exogenous developmental signals. These approaches often require extended periods of culture, which can limit their utility. However, more recently, it has become possible to produce neurons directly from fibroblasts using transcription factors and/or microRNAs. This technique referred to as direct reprogramming or transdifferentiation has proven to be a rapid, robust, and reproducible method to generate mature neurons of many different subtypes from multiple cell sources. Here, we highlight recent advances in generating neurons of specific subtypes using direct reprogramming and outline various scenarios in which induced neurons may be applied to studies of neuronal function and neurological disease.

  14. Heart development and regeneration via cellular interaction and reprogramming.

    PubMed

    Ieda, Masaki

    2013-01-01

    The heart consists of many types of cells, including cardiomyocytes, vascular cells, neural cells, and cardiac fibroblasts. Adult cardiomyocytes are terminally differentiated cells, and loss of cardiomyocytes as a result of heart damage is irreversible. To regenerate damaged hearts and restore cardiac function, understanding the cellular and molecular basis of heart development is of considerable importance. Although it is well known that heart function is tightly regulated by cell-cell interactions, their roles in heart development are not clear. Recent studies, including ours, identified important roles of cell-cell interactions in heart development and function. The balance between neural chemoattractants and chemorepellents secreted from cardiomyocytes determines cardiac nervous development. Nerve growth factor is a potent chemoattractant synthesized by cardiomyocytes, whereas Sema3a is a neural chemorepellent expressed specifically in the subendocardium. Disruption of this molecular balance induces disorganized cardiac innervation and may lead to sudden cardiac death due to lethal arrhythmias. Cardiac fibroblasts, of which there are large populations in the heart, secrete high levels of specific extracellular matrix and growth factors. Embryonic cardiac fibroblast-specific secreted factors collaboratively promote mitotic activity of embryonic cardiomyocytes and expansion of ventricular chambers during cardiogenesis. More recently, utilizing knowledge of the regulatory mechanisms of heart development, we found that cardiac fibroblasts can be directly reprogrammed into cardiomyocyte-like cells in vitro and in vivo by gene transfer of cardiac-specific transcription factors. Understanding the mechanisms of heart development and cardiac reprogramming technology may provide new therapeutic approaches for heart disease in the future.

  15. Strategies for heart regeneration: approaches ranging from induced pluripotent stem cells to direct cardiac reprogramming.

    PubMed

    Yamakawa, Hiroyuki; Ieda, Masaki

    2015-01-01

    Cardiovascular disease remains a leading cause of death for which current therapeutic regimens are limited. Following myocardial injury, endogenous cardiac fibroblasts, which account for more than half of the cells in the heart, proliferate and synthesize extracellular matrix, leading to fibrosis and heart failure. As terminally differentiated cardiomyocytes have little regenerative capacity following injury, development of cardiac regenerative therapy is highly desired. Embryonic stem (ES) and induced pluripotent stem (iPS) cells are promising tools for regenerative medicine; however, these stem cells demonstrate variable cardiac differentiation efficiency and tumorigenicity, which should be solved for clinical applications. Up until the last decade, it was an established theory that cardiomyocytes could only be produced from fibroblasts mediating through stem cells. However, in 2010, we reported for the first time a novel method of the direct reprogramming of fibroblasts into cardiomyocytes, demonstrating various reprogramming pathways exist. This review summarizes the latest trends in stem cell and regenerative research, touching upon iPS cells, partial reprogramming strategy, and direct cardiac reprogramming. Specifically, we examine the many recent advances in both in vitro and in vivo direct cardiac reprogramming, and explore the application of these methods to cardiovascular regenerative medicine.

  16. Transient acquisition of pluripotency during somatic cell transdifferentiation with iPSC reprogramming factors.

    PubMed

    Maza, Itay; Caspi, Inbal; Zviran, Asaf; Chomsky, Elad; Rais, Yoach; Viukov, Sergey; Geula, Shay; Buenrostro, Jason D; Weinberger, Leehee; Krupalnik, Vladislav; Hanna, Suhair; Zerbib, Mirie; Dutton, James R; Greenleaf, William J; Massarwa, Rada; Novershtern, Noa; Hanna, Jacob H

    2015-07-01

    Somatic cells can be transdifferentiated to other cell types without passing through a pluripotent state by ectopic expression of appropriate transcription factors. Recent reports have proposed an alternative transdifferentiation method in which fibroblasts are directly converted to various mature somatic cell types by brief expression of the induced pluripotent stem cell (iPSC) reprogramming factors Oct4, Sox2, Klf4 and c-Myc (OSKM) followed by cell expansion in media that promote lineage differentiation. Here we test this method using genetic lineage tracing for expression of endogenous Nanog and Oct4 and for X chromosome reactivation, as these events mark acquisition of pluripotency. We show that the vast majority of reprogrammed cardiomyocytes or neural stem cells obtained from mouse fibroblasts by OSKM-induced 'transdifferentiation' pass through a transient pluripotent state, and that their derivation is molecularly coupled to iPSC formation mechanisms. Our findings underscore the importance of defining trajectories during cell reprogramming by various methods.

  17. Supramolecular nanosubstrate-mediated delivery for reprogramming and transdifferentiation of mammalian cells.

    PubMed

    Hou, Shuang; Choi, Jin-sil; Chen, Kuan-Ju; Zhang, Yang; Peng, Jinliang; Garcia, Mitch A; Yu, Jue-Hua; Thakore-Shah, Kaushali; Ro, Tracy; Chen, Jie-Fu; Peyda, Parham; Fan, Guoping; Pyle, April D; Wang, Hao; Tseng, Hsian-Rong

    2015-06-03

    Supramolecular nanosubstrate-mediated delivery (SNSMD) leverages the power of molecular self-assembly and a nanostructured substrate platform for the low toxicity, highly efficient co-delivery of biological factors encapsulated in a nanovector. Human fibroblasts are successfully reprogrammed into induced pluripotent stems and transdifferentiated into induced neuronal-like cells.

  18. Reprogramming of somatic cells.

    PubMed

    Rajasingh, Johnson

    2012-01-01

    Reprogramming of adult somatic cells into pluripotent stem cells may provide an attractive source of stem cells for regenerative medicine. It has emerged as an invaluable method for generating patient-specific stem cells of any cell lineage without the use of embryonic stem cells. A revolutionary study in 2006 showed that it is possible to convert adult somatic cells directly into pluripotent stem cells by using a limited number of pluripotent transcription factors and is called as iPS cells. Currently, both genomic integrating viral and nonintegrating nonviral methods are used to generate iPS cells. However, the viral-based technology poses increased risk of safety, and more studies are now focused on nonviral-based technology to obtain autologous stem cells for clinical therapy. In this review, the pros and cons of the present iPS cell technology and the future direction for the successful translation of this technology into the clinic are discussed.

  19. Single cell analysis reveals the stochastic phase of reprogramming to pluripotency is an ordered probabilistic process.

    PubMed

    Chung, Kyung-Min; Kolling, Frederick W; Gajdosik, Matthew D; Burger, Steven; Russell, Alexander C; Nelson, Craig E

    2014-01-01

    Despite years of research, the reprogramming of human somatic cells to pluripotency remains a slow, inefficient process, and a detailed mechanistic understanding of reprogramming remains elusive. Current models suggest reprogramming to pluripotency occurs in two-phases: a prolonged stochastic phase followed by a rapid deterministic phase. In this paradigm, the early stochastic phase is marked by the random and gradual expression of pluripotency genes and is thought to be a major rate-limiting step in the successful generation of induced Pluripotent Stem Cells (iPSCs). Recent evidence suggests that the epigenetic landscape of the somatic cell is gradually reset during a period known as the stochastic phase, but it is known neither how this occurs nor what rate-limiting steps control progress through the stochastic phase. A precise understanding of gene expression dynamics in the stochastic phase is required in order to answer these questions. Moreover, a precise model of this complex process will enable the measurement and mechanistic dissection of treatments that enhance the rate or efficiency of reprogramming to pluripotency. Here we use single-cell transcript profiling, FACS and mathematical modeling to show that the stochastic phase is an ordered probabilistic process with independent gene-specific dynamics. We also show that partially reprogrammed cells infected with OSKM follow two trajectories: a productive trajectory toward increasingly ESC-like expression profiles or an alternative trajectory leading away from both the fibroblast and ESC state. These two pathways are distinguished by the coordinated expression of a small group of chromatin modifiers in the productive trajectory, supporting the notion that chromatin remodeling is essential for successful reprogramming. These are the first results to show that the stochastic phase of reprogramming in human fibroblasts is an ordered, probabilistic process with gene-specific dynamics and to provide a precise

  20. Direct Cardiac Reprogramming: From Developmental Biology to Cardiac Regeneration

    PubMed Central

    Qian, Li; Srivastava, Deepak

    2013-01-01

    Heart disease affects millions worldwide and is a progressive condition involving loss of cardiomyocytes. The human heart has limited endogenous regenerative capacity and is thus an important target for novel regenerative medicine approaches. While cell-based regenerative therapies hold promise, cellular reprogramming of endogenous cardiac fibroblasts, which represent more than half of the cells in the mammalian heart, may be an attractive alternative strategy for regenerating cardiac muscle. Recent advances leveraging years of developmental biology point to the feasibility of generating de novo cardiomyocyte-like cells from terminally differentiated non-myocytes in the heart in situ after ischemic damage. Here, we review the progress in cardiac reprogramming methods and consider the opportunities and challenges that lie ahead in refining this technology for regenerative medicine. PMID:24030021

  1. Direct Reprogramming-The Future of Cardiac Regeneration?

    PubMed

    Doppler, Stefanie A; Deutsch, Marcus-André; Lange, Rüdiger; Krane, Markus

    2015-07-29

    Today, the only available curative therapy for end stage congestive heart failure (CHF) is heart transplantation. This therapeutic option is strongly limited by declining numbers of available donor hearts and by restricted long-term performance of the transplanted graft. The disastrous prognosis for CHF with its restricted therapeutic options has led scientists to develop different concepts of alternative regenerative treatment strategies including stem cell transplantation or stimulating cell proliferation of different cardiac cell types in situ. However, first clinical trials with overall inconsistent results were not encouraging, particularly in terms of functional outcome. Among other approaches, very promising ongoing pre-clinical research focuses on direct lineage conversion of scar fibroblasts into functional myocardium, termed "direct reprogramming" or "transdifferentiation." This review seeks to summarize strategies for direct cardiac reprogramming including the application of different sets of transcription factors, microRNAs, and small molecules for an efficient generation of cardiomyogenic cells for regenerative purposes.

  2. Imprinting: DNA methyltransferases illuminate reprogramming.

    PubMed

    Calarco, Joseph P; Martienssen, Robert A

    2012-11-06

    Progress in studying epigenetic reprogramming in plants has been impeded by the difficulty in obtaining tissue for analysis. Now, using a combination of fluorescent reporters and translational fusions, a new study sheds some light on this process.

  3. Targeted gene therapy and cell reprogramming in Fanconi anemia

    PubMed Central

    Rio, Paula; Baños, Rocio; Lombardo, Angelo; Quintana-Bustamante, Oscar; Alvarez, Lara; Garate, Zita; Genovese, Pietro; Almarza, Elena; Valeri, Antonio; Díez, Begoña; Navarro, Susana; Torres, Yaima; Trujillo, Juan P; Murillas, Rodolfo; Segovia, Jose C; Samper, Enrique; Surralles, Jordi; Gregory, Philip D; Holmes, Michael C; Naldini, Luigi; Bueren, Juan A

    2014-01-01

    Gene targeting is progressively becoming a realistic therapeutic alternative in clinics. It is unknown, however, whether this technology will be suitable for the treatment of DNA repair deficiency syndromes such as Fanconi anemia (FA), with defects in homology-directed DNA repair. In this study, we used zinc finger nucleases and integrase-defective lentiviral vectors to demonstrate for the first time that FANCA can be efficiently and specifically targeted into the AAVS1 safe harbor locus in fibroblasts from FA-A patients. Strikingly, up to 40% of FA fibroblasts showed gene targeting 42 days after gene editing. Given the low number of hematopoietic precursors in the bone marrow of FA patients, gene-edited FA fibroblasts were then reprogrammed and re-differentiated toward the hematopoietic lineage. Analyses of gene-edited FA-iPSCs confirmed the specific integration of FANCA in the AAVS1 locus in all tested clones. Moreover, the hematopoietic differentiation of these iPSCs efficiently generated disease-free hematopoietic progenitors. Taken together, our results demonstrate for the first time the feasibility of correcting the phenotype of a DNA repair deficiency syndrome using gene-targeting and cell reprogramming strategies. PMID:24859981

  4. Genome-wide reprogramming in hybrids of somatic cells and embryonic stem cells.

    PubMed

    Ambrosi, Dominic J; Tanasijevic, Borko; Kaur, Anupinder; Obergfell, Craig; O'Neill, Rachel J; Krueger, Winfried; Rasmussen, Theodore P

    2007-05-01

    Recent experiments demonstrate that somatic nuclei can be reprogrammed to a pluripotent state when fused to ESCs. The resulting hybrids are pluripotent as judged by developmental assays, but detailed analyses of the underlying molecular-genetic control of reprogrammed transcription in such hybrids are required to better understand fusion-mediated reprogramming. We produced hybrids of mouse ESCs and fibroblasts that, although nearly tetraploid, exhibit characteristics of normal ESCs, including apparent immortality in culture, ESC-like colony morphology, and pluripotency. Comprehensive analysis of the mouse embryonic fibroblast/ESC hybrid transcriptome revealed global patterns of gene expression reminiscent of ESCs. However, combined analysis of variance and hierarchical clustering analyses revealed at least seven distinct classes of differentially regulated genes in comparisons of hybrids, ESCs, and somatic cells. The largest class includes somatic genes that are silenced in hybrids and ESCs, but a smaller class includes genes that are expressed at nearly equivalent levels in hybrids and ESCs that contain many genes implicated in pluripotency and chromatin function. Reprogrammed genes are distributed throughout the genome. Reprogramming events include both transcriptional silencing and activation of genes residing on chromosomes of somatic origin. Somatic/ESC hybrid cell lines resemble their pre-fusion ESC partners in terms of behavior in culture and pluripotency. However, they contain unique expression profiles that are similar but not identical to normal ESCs. ESC fusion-mediated reprogramming provides a tractable system for the investigation of mechanisms of reprogramming. Disclosure of potential conflicts of interest is found at the end of this article.

  5. Totipotency, Pluripotency and Nuclear Reprogramming

    NASA Astrophysics Data System (ADS)

    Mitalipov, Shoukhrat; Wolf, Don

    Mammalian development commences with the totipotent zygote which is capable of developing into all the specialized cells that make up the adult animal. As development unfolds, cells of the early embryo proliferate and differentiate into the first two lineages, the pluripotent inner cell mass and the trophectoderm. Pluripotent cells can be isolated, adapted and propagated indefinitely in vitro in an undifferentiated state as embryonic stem cells (ESCs). ESCs retain their ability to differentiate into cells representing the three major germ layers: endoderm, mesoderm or ectoderm or any of the 200+ cell types present in the adult body. Since many human diseases result from defects in a single cell type, pluripotent human ESCs represent an unlimited source of any cell or tissue type for replacement therapy thus providing a possible cure for many devastating conditions. Pluripotent cells resembling ESCs can also be derived experimentally by the nuclear reprogramming of somatic cells. Reprogrammed somatic cells may have an even more important role in cell replacement therapies since the patient's own somatic cells can be used for reprogramming thereby eliminating immune based rejection of transplanted cells. In this review, we summarize two major approaches to reprogramming: (1) somatic cell nuclear transfer and (2) direct reprogramming using genetic manipulations.

  6. Chromatin roadblocks to reprogramming 50 years on.

    PubMed

    Skene, Peter J; Henikoff, Steven

    2012-10-29

    A half century after John Gurdon demonstrated nuclear reprogramming, for which he was awarded the 2012 Nobel Prize in Physiology or Medicine, his group provides insights into the molecular mechanisms whereby chromatin remodeling is required for nuclear reprogramming. Among the issues addressed in Gurdon's latest work are the chromatin impediments to artificially induced reprogramming, discovered by Shinya Yamanaka, who shared the award with Gurdon.

  7. Biophysical regulation of epigenetic state and cell reprogramming

    NASA Astrophysics Data System (ADS)

    Downing, Timothy L.; Soto, Jennifer; Morez, Constant; Houssin, Timothee; Fritz, Ashley; Yuan, Falei; Chu, Julia; Patel, Shyam; Schaffer, David V.; Li, Song

    2013-12-01

    Biochemical factors can help reprogram somatic cells into pluripotent stem cells, yet the role of biophysical factors during reprogramming is unknown. Here, we show that biophysical cues, in the form of parallel microgrooves on the surface of cell-adhesive substrates, can replace the effects of small-molecule epigenetic modifiers and significantly improve reprogramming efficiency. The mechanism relies on the mechanomodulation of the cells’ epigenetic state. Specifically, decreased histone deacetylase activity and upregulation of the expression of WD repeat domain 5 (WDR5)—a subunit of H3 methyltranferase—by microgrooved surfaces lead to increased histone H3 acetylation and methylation. We also show that microtopography promotes a mesenchymal-to-epithelial transition in adult fibroblasts. Nanofibrous scaffolds with aligned fibre orientation produce effects similar to those produced by microgrooves, suggesting that changes in cell morphology may be responsible for modulation of the epigenetic state. These findings have important implications in cell biology and in the optimization of biomaterials for cell-engineering applications.

  8. Increasing Notch signaling antagonizes PRC2-mediated silencing to promote reprograming of germ cells into neurons

    PubMed Central

    Seelk, Stefanie; Adrian-Kalchhauser, Irene; Hargitai, Balázs; Hajduskova, Martina; Gutnik, Silvia; Tursun, Baris; Ciosk, Rafal

    2016-01-01

    Cell-fate reprograming is at the heart of development, yet very little is known about the molecular mechanisms promoting or inhibiting reprograming in intact organisms. In the C. elegans germline, reprograming germ cells into somatic cells requires chromatin perturbation. Here, we describe that such reprograming is facilitated by GLP-1/Notch signaling pathway. This is surprising, since this pathway is best known for maintaining undifferentiated germline stem cells/progenitors. Through a combination of genetics, tissue-specific transcriptome analysis, and functional studies of candidate genes, we uncovered a possible explanation for this unexpected role of GLP-1/Notch. We propose that GLP-1/Notch promotes reprograming by activating specific genes, silenced by the Polycomb repressive complex 2 (PRC2), and identify the conserved histone demethylase UTX-1 as a crucial GLP-1/Notch target facilitating reprograming. These findings have wide implications, ranging from development to diseases associated with abnormal Notch signaling. DOI: http://dx.doi.org/10.7554/eLife.15477.001 PMID:27602485

  9. Epigenetic reprogramming in plant sexual reproduction.

    PubMed

    Kawashima, Tomokazu; Berger, Frédéric

    2014-09-01

    Epigenetic reprogramming consists of global changes in DNA methylation and histone modifications. In mammals, epigenetic reprogramming is primarily associated with sexual reproduction and occurs during both gametogenesis and early embryonic development. Such reprogramming is crucial not only to maintain genomic integrity through silencing transposable elements but also to reset the silenced status of imprinted genes. In plants, observations of stable transgenerational inheritance of epialleles have argued against reprogramming. However, emerging evidence supports that epigenetic reprogramming indeed occurs during sexual reproduction in plants and that it has a major role in maintaining genome integrity and a potential contribution to epiallelic variation.

  10. Cell reprogramming: Into the groove

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Liu, Longqi; Laslett, Andrew L.; Esteban, Miguel A.

    2013-12-01

    Adult cells can be routinely reprogrammed into pluripotent stem cells by chemical and genetic means, such as the expression of a cocktail of exogenous transcription factors. It is now shown that growing cells on substrates with aligned features such as microgrooves can enhance this process.

  11. Glycolytic Reprogramming in Myofibroblast Differentiation and Lung Fibrosis

    PubMed Central

    Xie, Na; Tan, Zheng; Banerjee, Sami; Cui, Huachun; Ge, Jing; Liu, Rui-Ming; Bernard, Karen; Thannickal, Victor J.

    2015-01-01

    Rationale: Dysregulation of cellular metabolism has been shown to participate in several pathologic processes. However, the role of metabolic reprogramming is not well appreciated in the pathogenesis of organ fibrosis. Objectives: To determine if glycolytic reprogramming participates in the pathogenesis of lung fibrosis and assess the therapeutic potential of glycolytic inhibition in treating lung fibrosis. Methods: A cell metabolism assay was performed to determine glycolytic flux and mitochondrial respiration. Lactate levels were measured to assess glycolysis in fibroblasts and lungs. Glycolytic inhibition by genetic and pharmacologic approaches was used to demonstrate the critical role of glycolysis in lung fibrosis. Measurements and Main Results: Augmentation of glycolysis is an early and sustained event during myofibroblast differentiation, which is dependent on the increased expression of critical glycolytic enzymes, in particular, 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3). Augmented glycolysis contributes to the stabilization of hypoxia-inducible factor 1-α, a master regulator of glycolytic enzymes implicated in organ fibrosis, by increasing cellular levels of tricarboxylic acid cycle intermediate succinate in lung myofibroblasts. Inhibition of glycolysis by the PFKFB3 inhibitor 3PO or genomic disruption of the PFKFB3 gene blunted the differentiation of lung fibroblasts into myofibroblasts, and attenuated profibrotic phenotypes in myofibroblasts isolated from the lungs of patients with idiopathic pulmonary fibrosis. Inhibition of glycolysis by 3PO demonstrates therapeutic benefit in bleomycin-induced and transforming growth factor-β1–induced lung fibrosis in mice. Conclusions: Our data support the novel concept of glycolytic reprogramming in the pathogenesis of lung fibrosis and provide proof-of-concept that targeting this pathway may be efficacious in treating fibrotic disorders, such as idiopathic pulmonary fibrosis. PMID:26284610

  12. Murine somatic cell nuclear transfer using reprogrammed donor cells expressing male germ cell-specific genes.

    PubMed

    Kang, Hoin; Park, Jong Im; Roh, Sangho

    2016-01-01

    In vivo-matured mouse oocytes were enucleated, and a single murine embryonic fibroblast (control or reprogrammed by introducing extracts from murine testis tissue, which showed expression of male germ cell-specific genes) was injected into the cytoplasm of the oocytes. The rate of blastocyst development and expression levels of Oct-4, Eomes and Cdx-2 were not significantly different in both experimental groups. However, the expression levels of Nanog, Sox9 and Glut-1 were significantly increased when reprogrammed cells were used as donor nuclei. Increased expression of Nanog can be supportive of complete reprogramming of somatic cell nuclear transfer murine embryos. The present study suggested that donor cells expressing male germ cell-specific genes can be reconstructed and can develop into embryos with normal high expression of developmentally essential genes.

  13. Analysis of nuclear reprogramming in cloned miniature pig embryos by expression of Oct-4 and Oct-4 related genes

    SciTech Connect

    Lee, Eugine; Lee, So Hyun; Kim, Sue

    2006-10-06

    Xenotransplantation is a rapidly expanding field of research and cloned miniature pigs have been considered as a model animal for it. However, the efficiency of somatic cell nuclear transfer (SCNT) is extremely low, with most clones resulting in early lethality and several kinds of aberrant development. A possible explanation for the developmental failure of SCNT embryos is insufficient reprogramming of the somatic cell nucleus by the oocyte. In order to test this, we analyzed the reprogramming capacity of differentiated fibroblast cell nuclei and embryonic germ cell nuclei with Oct-4 and Oct-4 related genes (Ndp5211, Dppa2, Dppa3, and Dppa5), which are important for embryonic development, Hand1 and GATA-4, which are important for placental development, as molecular markers using RT-PCR. The Oct-4 expression level was significantly lower (P < 0.05) in cloned hatched blastocysts derived from fibroblasts and many of fibroblast-derived clones failed to reactivate at least one of the tested genes, while most of the germ cell clones and control embryos correctly expressed these genes. In conclusion, our results suggest that the reprogramming of fibroblast-derived cloned embryos is highly aberrant and this improper reprogramming could be one reason of the early lethality and post-implantation anomalies of somatic cell-derived clones.

  14. Tet-mediated imprinting erasure in H19 locus following reprogramming of spermatogonial stem cells to induced pluripotent stem cells.

    PubMed

    Bermejo-Álvarez, P; Ramos-Ibeas, P; Park, K E; Powell, A P; Vansandt, L; Derek, Bickhart; Ramirez, M A; Gutiérrez-Adán, A; Telugu, B P

    2015-09-02

    Selective methylation of CpG islands at imprinting control regions (ICR) determines the monoparental expression of a subset of genes. Currently, it is unclear whether artificial reprogramming induced by the expression of Yamanaka factors disrupts these marks and whether cell type of origin affects the dynamics of reprogramming. In this study, spermatogonial stem cells (SSC) that harbor paternalized imprinting marks, and fibroblasts were reprogrammed to iPSC (SSCiPSC and fiPSC). The SSCiPSC were able to form teratomas and generated chimeras with a higher skin chimerism than those derived from fiPSC. RNA-seq revealed extensive reprogramming at the transcriptional level with 8124 genes differentially expressed between SSC and SSCiPSC and only 490 between SSCiPSC and fiPSC. Likewise, reprogramming of SSC affected 26 of 41 imprinting gene clusters known in the mouse genome. A closer look at H19 ICR revealed complete erasure in SSCiPSC in contrast to fiPSC. Imprinting erasure in SSCiPSC was maintained even after in vivo differentiation into teratomas. Reprogramming of SSC from Tet1 and Tet2 double knockout mice however lacked demethylation of H19 ICR. These results suggest that imprinting erasure during reprogramming depends on the epigenetic landscape of the precursor cell and is mediated by TETs at the H19 locus.

  15. Tet-mediated imprinting erasure in H19 locus following reprogramming of spermatogonial stem cells to induced pluripotent stem cells

    PubMed Central

    Bermejo-Álvarez, P.; Ramos-Ibeas, P.; Park, K.E.; Powell, A. P.; Vansandt, L.; Derek, Bickhart; Ramirez, M. A.; Gutiérrez-Adán, A.; Telugu, B. P.

    2015-01-01

    Selective methylation of CpG islands at imprinting control regions (ICR) determines the monoparental expression of a subset of genes. Currently, it is unclear whether artificial reprogramming induced by the expression of Yamanaka factors disrupts these marks and whether cell type of origin affects the dynamics of reprogramming. In this study, spermatogonial stem cells (SSC) that harbor paternalized imprinting marks, and fibroblasts were reprogrammed to iPSC (SSCiPSC and fiPSC). The SSCiPSC were able to form teratomas and generated chimeras with a higher skin chimerism than those derived from fiPSC. RNA-seq revealed extensive reprogramming at the transcriptional level with 8124 genes differentially expressed between SSC and SSCiPSC and only 490 between SSCiPSC and fiPSC. Likewise, reprogramming of SSC affected 26 of 41 imprinting gene clusters known in the mouse genome. A closer look at H19 ICR revealed complete erasure in SSCiPSC in contrast to fiPSC. Imprinting erasure in SSCiPSC was maintained even after in vivo differentiation into teratomas. Reprogramming of SSC from Tet1 and Tet2 double knockout mice however lacked demethylation of H19 ICR. These results suggest that imprinting erasure during reprogramming depends on the epigenetic landscape of the precursor cell and is mediated by TETs at the H19 locus. PMID:26328763

  16. The histone demethylases Jhdm1a/1b enhance somatic cell reprogramming in a vitamin-C-dependent manner.

    PubMed

    Wang, Tao; Chen, Keshi; Zeng, Xiaoming; Yang, Jianguo; Wu, Yun; Shi, Xi; Qin, Baoming; Zeng, Lingwen; Esteban, Miguel Angel; Pan, Guangjin; Pei, Duanqing

    2011-12-02

    Reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) resets the epigenome to an embryonic-like state. Vitamin C enhances the reprogramming process, but the underlying mechanisms are unclear. Here we show that the histone demethylases Jhdm1a/1b are key effectors of somatic cell reprogramming downstream of vitamin C. We first observed that vitamin C induces H3K36me2/3 demethylation in mouse embryonic fibroblasts in culture and during reprogramming. We then identified Jhdm1a/1b, two known vitamin-C-dependent H3K36 demethylases, as potent regulators of reprogramming through gain- and loss-of-function approaches. Furthermore, we found that Jhdm1b accelerates cell cycle progression and suppresses cell senescence during reprogramming by repressing the Ink4/Arf locus. Jhdm1b also cooperates with Oct4 to activate the microRNA cluster 302/367, an integral component of the pluripotency machinery. Our results therefore reveal a role for H3K36me2/3 in cell fate determination and establish a link between histone demethylases and vitamin-C-induced reprogramming.

  17. Retinoic Acid Inducible Gene 1 Protein (RIG1)-Like Receptor Pathway Is Required for Efficient Nuclear Reprogramming.

    PubMed

    Sayed, Nazish; Ospino, Frank; Himmati, Farhan; Lee, Jieun; Chanda, Palas; Mocarski, Edward S; Cooke, John P

    2017-03-09

    We have revealed a critical role for innate immune signaling in nuclear reprogramming to pluripotency, and in the nuclear reprogramming required for somatic cell transdifferentiation. Activation of innate immune signaling causes global changes in the expression and activity of epigenetic modifiers to promote epigenetic plasticity. In our previous articles, we focused on the role of toll-like receptor 3 (TLR3) in this signaling pathway. Here, we define the role of another innate immunity pathway known to participate in response to viral RNA, the retinoic acid-inducible gene 1 receptor (RIG-1)-like receptor (RLR) pathway. This pathway is represented by the sensors of viral RNA, RIG-1, LGP2, and melanoma differentiation-associated protein 5 (MDA5). We first found that TLR3 deficiency only causes a partial inhibition of nuclear reprogramming to pluripotency in mouse tail-tip fibroblasts, which motivated us to determine the contribution of RLR. We found that knockdown of interferon beta promoter stimulator 1, the common adaptor protein for the RLR family, substantially reduced nuclear reprogramming induced by retroviral or by modified messenger RNA expression of Oct 4, Sox2, KLF4, and c-MYC (OSKM). Importantly, a double knockdown of both RLR and TLR3 pathway led to a further decrease in induced pluripotent stem cell (iPSC) colonies suggesting an additive effect of both these pathways on nuclear reprogramming. Furthermore, in murine embryonic fibroblasts expressing a doxycycline (dox)-inducible cassette of the genes encoding OSKM, an RLR agonist increased the yield of iPSCs. Similarly, the RLR agonist enhanced nuclear reprogramming by cell permeant peptides of the Yamanaka factors. Finally, in the dox-inducible system, RLR activation promotes activating histone marks in the promoter region of pluripotency genes. To conclude, innate immune signaling mediated by RLR plays a critical role in nuclear reprogramming. Manipulation of innate immune signaling may facilitate

  18. Production of De Novo Cardiomyocytes: Human Pluripotent Stem Cell Differentiation and Direct Reprogramming

    PubMed Central

    Burridge, Paul W.; Keller, Gordon; Gold, Joseph D.; Wu, Joseph C.

    2012-01-01

    SUMMARY Cardiovascular disease is a leading cause of death worldwide. The limited capability of heart tissue to regenerate has prompted method developments for creating de novo cardiomyocytes, both in vitro and in vivo. Beyond uses in cell replacement therapy, patient-specific cardiomyocytes may find applications in drug testing, drug discovery, and disease modeling. Recently, approaches for generating cardiomyocytes have expanded to encompass three major sources of starting cells: human pluripotent stem cells (hPSCs), adult heart-derived cardiac progenitor cells (CPCs), and reprogrammed fibroblasts. We discuss state-of-the-art methods for generating de novo cardiomyocytes from hPSC and reprogrammed fibroblasts, highlighting potential applications and future challenges. PMID:22226352

  19. The cellular memory disc of reprogrammed cells.

    PubMed

    Anjamrooz, Seyed Hadi

    2013-04-01

    The crucial facts underlying the low efficiency of cellular reprogramming are poorly understood. Cellular reprogramming occurs in nuclear transfer, induced pluripotent stem cell (iPSC) formation, cell fusion, and lineage-switching experiments. Despite these advances, there are three fundamental problems to be addressed: (1) the majority of cells cannot be reprogrammed, (2) the efficiency of reprogramming cells is usually low, and (3) the reprogrammed cells developed from a patient's own cells activate immune responses. These shortcomings present major obstacles for using reprogramming approaches in customised cell therapy. In this Perspective, the author synthesises past and present observations in the field of cellular reprogramming to propose a theoretical picture of the cellular memory disc. The current hypothesis is that all cells undergo an endogenous and exogenous holographic memorisation such that parts of the cellular memory dramatically decrease the efficiency of reprogramming cells, act like a barrier against reprogramming in the majority of cells, and activate immune responses. Accordingly, the focus of this review is mainly to describe the cellular memory disc (CMD). Based on the present theory, cellular memory includes three parts: a reprogramming-resistance memory (RRM), a switch-promoting memory (SPM) and a culture-induced memory (CIM). The cellular memory arises genetically, epigenetically and non-genetically and affects cellular behaviours. [corrected].

  20. Reprogramming Methods Do Not Affect Gene Expression Profile of Human Induced Pluripotent Stem Cells

    PubMed Central

    Trevisan, Marta; Desole, Giovanna; Costanzi, Giulia; Lavezzo, Enrico; Palù, Giorgio; Barzon, Luisa

    2017-01-01

    Induced pluripotent stem cells (iPSCs) are pluripotent cells derived from adult somatic cells. After the pioneering work by Yamanaka, who first generated iPSCs by retroviral transduction of four reprogramming factors, several alternative methods to obtain iPSCs have been developed in order to increase the yield and safety of the process. However, the question remains open on whether the different reprogramming methods can influence the pluripotency features of the derived lines. In this study, three different strategies, based on retroviral vectors, episomal vectors, and Sendai virus vectors, were applied to derive iPSCs from human fibroblasts. The reprogramming efficiency of the methods based on episomal and Sendai virus vectors was higher than that of the retroviral vector-based approach. All human iPSC clones derived with the different methods showed the typical features of pluripotent stem cells, including the expression of alkaline phosphatase and stemness maker genes, and could give rise to the three germ layer derivatives upon embryoid bodies assay. Microarray analysis confirmed the presence of typical stem cell gene expression profiles in all iPSC clones and did not identify any significant difference among reprogramming methods. In conclusion, the use of different reprogramming methods is equivalent and does not affect gene expression profile of the derived human iPSCs. PMID:28117672

  1. Reprogramming plant cells for endosymbiosis.

    PubMed

    Oldroyd, Giles E D; Harrison, Maria J; Paszkowski, Uta

    2009-05-08

    The establishment of arbuscular mycorrhizal (AM) symbioses, formed by most flowering plants in association with glomeromycotan fungi, and the root-nodule (RN) symbiosis, formed by legume plants and rhizobial bacteria, requires an ongoing molecular dialogue that underpins the reprogramming of root cells for compatibility. In both endosymbioses, there are distinct phases to the interaction, including a presymbiotic anticipation phase and, subsequently, an intraradical accommodation of the microsymbiont. Maintenance of the endosymbiosis then depends on reciprocal nutrient exchange with the microsymbiont-obtaining plant photosynthates in exchange for mineral nutrients: enhanced phosphate and nitrogen uptake from AM fungi and fixed nitrogen from rhizobia. Despite the taxonomically distinct groups of symbionts, commonalities are observed in the signaling components and the modulation of host cell responses in both AM and RN symbioses, reflecting common mechanisms for plant cell reprogramming during endosymbiosis.

  2. Optical reprogramming of human somatic cells using ultrashort Bessel-shaped near-infrared femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Uchugonova, Aisada; Breunig, Hans Georg; Batista, Ana; König, Karsten

    2015-11-01

    We report a virus-free optical approach to human cell reprogramming into induced pluripotent stem cells with low-power nanoporation using ultrashort Bessel-shaped laser pulses. Picojoule near-infrared sub-20 fs laser pulses at a high 85 MHz repetition frequency are employed to generate transient nanopores in the membrane of dermal fibroblasts for the introduction of four transcription factors to induce the reprogramming process. In contrast to conventional approaches which utilize retro- or lentiviruses to deliver genes or transcription factors into the host genome, the laser method is virus-free; hence, the risk of virus-induced cancer generation limiting clinical application is avoided.

  3. Optical reprogramming of human somatic cells using ultrashort Bessel-shaped near-infrared femtosecond laser pulses.

    PubMed

    Uchugonova, Aisada; Breunig, Hans Georg; Batista, Ana; König, Karsten

    2015-11-01

    We report a virus-free optical approach to human cell reprogramming into induced pluripotent stem cells with low-power nanoporation using ultrashort Bessel-shaped laser pulses. Picojoule near-infrared sub-20 fs laser pulses at a high 85 MHz repetition frequency are employed to generate transient nanopores in the membrane of dermal fibroblasts for the introduction of four transcription factors to induce the reprogramming process. In contrast to conventional approaches which utilize retro- or lentiviruses to deliver genes or transcription factors into the host genome, the laser method is virus-free; hence, the risk of virus-induced cancer generation limiting clinical application is avoided.

  4. Oct4 and klf4 reprogram dermal papilla cells into induced pluripotent stem cells.

    PubMed

    Tsai, Su-Yi; Clavel, Carlos; Kim, Soo; Ang, Yen-Sin; Grisanti, Laura; Lee, Dung-Fang; Kelley, Kevin; Rendl, Michael

    2010-02-01

    Direct reprogramming of somatic cells into induced pluripotent stem (iPS) cells by only four transcription factors (Oct4, Sox2, Klf4, and c-Myc) has great potential for tissue-specific regenerative therapies, eliminating the ethical issues surrounding the use of embryonic stem cells and the rejection problems of using non-autologous cells. The reprogramming efficiency generally is very low, however, and the problems surrounding the introduction of viral genetic material are only partially investigated. Recent efforts to reduce the number of virally expressed transcription factors succeeded at reprogramming neural stem cells into iPS cells by overexpressing Oct4 alone. However, the relative inaccessibility and difficulty of obtaining neural cells in humans remains to be resolved. Here we report that dermal papilla (DP) cells, which are specialized skin fibroblasts thought to instruct hair follicle stem cells, endogenously express high levels of Sox2 and c-Myc, and that these cells can be reprogrammed into iPS cells with only Oct4 and Klf4. Moreover, we show that DP cells are reprogrammed more efficiently than skin and embryonic fibroblasts. iPS cells derived from DP cells expressed pluripotency genes and differentiated into cells from all germ layers in vitro and widely contributed to chimeric mice in vivo, including the germline. Our work establishes DP cells as an easily accessible source to generate iPS cells with efficiency and with less genetic material. This opens up the possibility of streamlined generation of skin-derived, patient-specific pluripotent stem cells and of ultimately replacing the remaining two factors with small molecules for safe generation of transplantable cells.

  5. Actin stress in cell reprogramming

    PubMed Central

    Guo, Jun; Wang, Yuexiu; Sachs, Frederick; Meng, Fanjie

    2014-01-01

    Cell mechanics plays a role in stem cell reprogramming and differentiation. To understand this process better, we created a genetically encoded optical probe, named actin–cpstFRET–actin (AcpA), to report forces in actin in living cells in real time. We showed that stemness was associated with increased force in actin. We reprogrammed HEK-293 cells into stem-like cells using no transcription factors but simply by softening the substrate. However, Madin-Darby canine kidney (MDCK) cell reprogramming required, in addition to a soft substrate, Harvey rat sarcoma viral oncogene homolog expression. Replating the stem-like cells on glass led to redifferentiation and reduced force in actin. The actin force probe was a FRET sensor, called cpstFRET (circularly permuted stretch sensitive FRET), flanked by g-actin subunits. The labeled actin expressed efficiently in HEK, MDCK, 3T3, and bovine aortic endothelial cells and in multiple stable cell lines created from those cells. The viability of the cell lines demonstrated that labeled actin did not significantly affect cell physiology. The labeled actin distribution was similar to that observed with GFP-tagged actin. We also examined the stress in the actin cross-linker actinin. Actinin force was not always correlated with actin force, emphasizing the need for addressing protein specificity when discussing forces. Because actin is a primary structural protein in animal cells, understanding its force distribution is central to understanding animal cell physiology and the many linked reactions such as stress-induced gene expression. This new probe permits measuring actin forces in a wide range of experiments on preparations ranging from isolated proteins to transgenic animals. PMID:25422450

  6. Reprogramming with defined factors: from induced pluripotency to induced transdifferentiation.

    PubMed

    Masip, Manuel; Veiga, Anna; Izpisúa Belmonte, Juan Carlos; Simón, Carlos

    2010-11-01

    Ever since work on pluripotency induction was originally published, reporting the reprogramming of somatic cells to induced pluripotent stem cells (iPS cells) by the ectopic expression of the four transcription factors Oct4, Sox2, Klf4 and c-Myc, high expectations regarding their potential use for regenerative medicine have emerged. Very recently, the direct conversion of fibroblasts into functional neurons with no prior pluripotent stage has been described. Interconversion between adult cells from ontogenically different lineages by an induced transdifferentiation process based on the overexpression of a cocktail of transcription factors, while avoiding transition through an embryonic stem cell-like state, provides a new impetus in the field of regenerative medicine. Here, we review the induced reprogramming of somatic cells with defined factors and analyze their potential clinical use. Beginning with induced pluripotency, we summarize the initial objections including their extremely low efficiency and the risk of tumor generation. We also review recent reports describing iPS cells' capacity to generate viable offspring through tetraploid complementation, the most restrictive pluripotency criterion. Finally, we explore the available evidence for 'induced transdifferentiated cells' as a novel tool for adult cell fate modification.

  7. Chinese Herbs Interfering with Cancer Reprogramming Metabolism

    PubMed Central

    Zhong, Zhangfeng; Qiang, William W.; Tan, Wen; Zhang, Haotian; Wang, Shengpeng; Wang, Chunming; Qiang, Wenan; Wang, Yitao

    2016-01-01

    Emerging evidence promotes a reassessment of metabolic reprogramming regulation in cancer research. Although there exists a long history of Chinese herbs applied in cancer treatment, few reports have addressed the effects of Chinese herbal components on metabolic reprogramming, which is a central cancer hallmark involved in the slowing or prevention of chemoresistance in cancer cells. In this review, we have focused on four core elements altered by metabolic reprogramming in cancer cells. These include glucose transport, glycolysis, mitochondrial oxidative phosphorylation, and fatty acid synthesis. With this focus, we have summarized recent advances in metabolic reprogramming of cancer cells in response to specific Chinese herbal components. We propose that exploring Chinese herbal interference in cancer metabolic reprogramming might identify new therapeutic targets for cancer and more ways in which to approach metabolism-related diseases. PMID:27242914

  8. Telomerase Reverse Transcriptase Has an Extratelomeric Function in Somatic Cell Reprogramming*

    PubMed Central

    Kinoshita, Taisuke; Nagamatsu, Go; Saito, Shigeru; Takubo, Keiyo; Horimoto, Katsuhisa; Suda, Toshio

    2014-01-01

    Reactivation of the endogenous telomerase reverse transcriptase (TERT) catalytic subunit and telomere elongation occur during the reprogramming of somatic cells to induced pluripotent stem (iPS) cells. However, the role of TERT in the reprogramming process is unclear. To clarify its function, the reprogramming process was examined in TERT-KO somatic cells. To exclude the effect of telomere elongation, tail-tip fibroblasts (TTFs) from first generation TERT-KO mice were used. Although iPS cells were successfully generated from TERT-KO TTFs, the efficiency of reprogramming these cells was markedly lower than that of WT TTFs. The gene expression profiles of iPS cells induced from TERT-KO TTFs were similar to those of WT iPS cells and ES cells, and TERT-KO iPS cells formed teratomas that differentiated into all three germ layers. These data indicate that TERT plays an extratelomeric role in the reprogramming process, but its function is dispensable. However, TERT-KO iPS cells showed transient defects in growth and teratoma formation during continuous growth. In addition, TERT-KO iPS cells developed chromosome fusions that accumulated with increasing passage numbers, consistent with the fact that TERT is essential for the maintenance of genome structure and stability in iPS cells. In a rescue experiment, an enzymatically inactive mutant of TERT (D702A) had a positive effect on somatic cell reprogramming of TERT-KO TTFs, which confirmed the extratelomeric role of TERT in this process. PMID:24733392

  9. [Ethical reflections on cell reprogramming].

    PubMed

    Aznar Lucea, Justo; Martínez, Miriam

    2012-01-01

    New advances in cell reprogramming, and particularly in obtaining iPS cells, have represented a promising possibility for avoiding the use of human embryonic cells in experimental research and clinical medicine, use which is ethically unacceptable, as obtaining these cells requires the destruction of human embryos. The road travelled to arrive at the discovery of iPS cells, and especially the ethical assessment of each of the steps taken to that end, are evaluated in this paper. The ethical judgement merited by the various uses that can be made of iPS cells is also examined, because just when it seemed that iPS cells could resolve the ethical problems inherent to the use of embryonic stem cells, new possibilities for using iPS cells, especially related with human reproduction, have opened up expectations for using these cells that are far removed from the most fundamental ethical standards. We conclude that the ethical debate on cell reprogramming and particularly on the experimental and clinical use of iPS cells remains open.

  10. Global transcriptomic analysis of induced cardiomyocytes predicts novel regulators for direct cardiac reprogramming.

    PubMed

    Talkhabi, Mahmood; Razavi, Seyed Morteza; Salari, Ali

    2017-04-04

    Heart diseases are the most significant cause of morbidity and mortality in the world. De novo generated cardiomyocytes (CMs) are a great cellular source for cell-based therapy and other potential applications. Direct cardiac reprogramming is the newest method to produce CMs, known as induced cardiomyocytes (iCMs). During a direct cardiac reprogramming, also known as transdifferentiation, non-cardiac differentiated adult cells are reprogrammed to cardiac identity by forced expression of cardiac-specific transcription factors (TFs) or microRNAs. To this end, many different combinations of TFs (±microRNAs) have been reported for direct reprogramming of mouse or human fibroblasts to iCMs, although their efficiencies remain very low. It seems that the investigated TFs and microRNAs are not sufficient for efficient direct cardiac reprogramming and other cardiac specific factors may be required for increasing iCM production efficiency, as well as the quality of iCMs. Here, we analyzed gene expression data of cardiac fibroblast (CFs), iCMs and adult cardiomyocytes (aCMs). The up-regulated and down-regulated genes in CMs (aCMs and iCMs) were determined as CM and CF specific genes, respectively. Among CM specific genes, we found 153 transcriptional activators including some cardiac and non-cardiac TFs that potentially activate the expression of CM specific genes. We also identified that 85 protein kinases such as protein kinase D1 (PKD1), protein kinase A (PRKA), calcium/calmodulin-dependent protein kinase (CAMK), protein kinase C (PRKC), and insulin like growth factor 1 receptor (IGF1R) that are strongly involved in establishing CM identity. CM gene regulatory network constructed using protein kinases, transcriptional activators and intermediate proteins predicted some new transcriptional activators such as myocyte enhancer factor 2A (MEF2A) and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PPARGC1A), which may be required for qualitatively and

  11. Epigenetic reprogramming in somatic cells induced by extract from germinal vesicle stage pig oocytes.

    PubMed

    Bui, Hong-Thuy; Kwon, Deug-Nam; Kang, Min-Hui; Oh, Mi-Hye; Park, Mi-Ryung; Park, Woo-Jin; Paik, Seung-Sam; Van Thuan, Nguyen; Kim, Jin-Hoi

    2012-12-01

    Genomic reprogramming factors in the cytoplasm of germinal vesicle (GV) stage oocytes have been shown to improve the efficiency of producing cloned mouse offspring through the exposure of nuclei to a GV cytoplasmic extract prior to somatic cell nuclear transfer (SCNT) to enucleated oocytes. Here, we developed an extract of GV stage pig oocytes (GVcyto-extract) to investigate epigenetic reprogramming events in treated somatic cell nuclei. This extract induced differentiation-associated changes in fibroblasts, resulting in cells that exhibit pluripotent stem cell-like characteristics and that redifferentiate into three primary germ cell layers both in vivo and in vitro. The GVcyto-extract treatment induced large numbers of high-quality SCNT-generated blastocysts, with methylation and acetylation of H3-K9 and expression of Oct4 and Nanog at levels similar to in vitro fertilized embryos. Thus, GVcyto-extract could elicit differentiation plasticity in treated fibroblasts, and SCNT-mediated reprogramming reset the epigenetic state in treated cells more efficiently than in untreated cells. In summary, we provide evidence for the generation of stem-like cells from differentiated somatic cells by treatment with porcine GVcyto-extract.

  12. Lentiviral vector design and imaging approaches to visualize the early stages of cellular reprogramming.

    PubMed

    Warlich, Eva; Kuehle, Johannes; Cantz, Tobias; Brugman, Martijn H; Maetzig, Tobias; Galla, Melanie; Filipczyk, Adam A; Halle, Stephan; Klump, Hannes; Schöler, Hans R; Baum, Christopher; Schroeder, Timm; Schambach, Axel

    2011-04-01

    Induced pluripotent stem cells (iPSCs) can be derived from somatic cells by gene transfer of reprogramming transcription factors. Expression levels of these factors strongly influence the overall efficacy to form iPSC colonies, but additional contribution of stochastic cell-intrinsic factors has been proposed. Here, we present engineered color-coded lentiviral vectors in which codon-optimized reprogramming factors are co-expressed by a strong retroviral promoter that is rapidly silenced in iPSC, and imaged the conversion of fibroblasts to iPSC. We combined fluorescence microscopy with long-term single cell tracking, and used live-cell imaging to analyze the emergence and composition of early iPSC clusters. Applying our engineered lentiviral vectors, we demonstrate that vector silencing typically occurs prior to or simultaneously with the induction of an Oct4-EGFP pluripotency marker. Around 7 days post-transduction (pt), a subfraction of cells in clonal colonies expressed Oct4-EGFP and rapidly expanded. Cell tracking of single cell-derived iPSC colonies supported the concept that stochastic epigenetic changes are necessary for reprogramming. We also found that iPSC colonies may emerge as a genetic mosaic originating from different clusters. Improved vector design with continuous cell tracking thus creates a powerful system to explore the subtle dynamics of biological processes such as early reprogramming events.

  13. Ordered chromatin changes and human X chromosome reactivation by cell fusion-mediated pluripotent reprogramming

    PubMed Central

    Cantone, Irene; Bagci, Hakan; Dormann, Dirk; Dharmalingam, Gopuraja; Nesterova, Tatyana; Brockdorff, Neil; Rougeulle, Claire; Vallot, Celine; Heard, Edith; Chaligne, Ronan; Merkenschlager, Matthias; Fisher, Amanda G.

    2016-01-01

    Erasure of epigenetic memory is required to convert somatic cells towards pluripotency. Reactivation of the inactive X chromosome (Xi) has been used to model epigenetic reprogramming in mouse, but human studies are hampered by Xi epigenetic instability and difficulties in tracking partially reprogrammed iPSCs. Here we use cell fusion to examine the earliest events in the reprogramming-induced Xi reactivation of human female fibroblasts. We show that a rapid and widespread loss of Xi-associated H3K27me3 and XIST occurs in fused cells and precedes the bi-allelic expression of selected Xi-genes by many heterokaryons (30–50%). After cell division, RNA-FISH and RNA-seq analyses confirm that Xi reactivation remains partial and that induction of human pluripotency-specific XACT transcripts is rare (1%). These data effectively separate pre- and post-mitotic events in reprogramming-induced Xi reactivation and reveal a complex hierarchy of epigenetic changes that are required to reactivate the genes on the human Xi chromosome. PMID:27507283

  14. Reprogramming cell fate: a changing story.

    PubMed

    Chin, Michael T

    2014-01-01

    Direct reprogramming of adult, lineage-determined cells from one cell fate to another has long been an elusive goal in developmental biology. Recent studies have demonstrated that forced expression of lineage-specific transcription factors in various differentiated cell types can promote the adoption of different lineages. These seminal findings have the potential to revolutionize the field of regenerative medicine by providing replacement cells for various degenerative disorders. Current reprogramming protocols, however, are inefficient in that relatively few cells in a given population can be made to undergo reprogramming and the completeness and extent of reprogramming that occurs has been questioned. At present, the fundamental molecular mechanisms involved are still being elucidated. Although the potential clinical applications are extensive, these issues will need to be addressed before direct reprogramming may be used clinically. This review will give an overview of pioneering studies in the field, will describe what is known about direct reprogramming to specific lineage types, will summarize what is known about the molecular mechanisms involved in reprogramming and will discuss challenges for the future.

  15. Metabolic remodeling of the tumor microenvironment: migration stimulating factor (MSF) reprograms myofibroblasts toward lactate production, fueling anabolic tumor growth.

    PubMed

    Carito, Valentina; Bonuccelli, Gloria; Martinez-Outschoorn, Ubaldo E; Whitaker-Menezes, Diana; Caroleo, Maria Cristina; Cione, Erika; Howell, Anthony; Pestell, Richard G; Lisanti, Michael P; Sotgia, Federica

    2012-09-15

    Migration stimulating factor (MSF) is a genetically truncated N-terminal isoform of fibronectin that is highly expressed during mammalian development in fetal fibroblasts, and during tumor formation in human cancer-associated myofibroblasts. However, its potential functional role in regulating tumor metabolism remains unexplored. Here, we generated an immortalized fibroblast cell line that recombinantly overexpresses MSF and studied their properties relative to vector-alone control fibroblasts. Our results indicate that overexpression of MSF is sufficient to confer myofibroblastic differentiation, likely via increased TGF-b signaling. In addition, MSF activates the inflammation-associated transcription factor NFκB, resulting in the onset of autophagy/mitophagy, thereby driving glycolytic metabolism (L-lactate production) in the tumor microenvironment. Consistent with the idea that glycolytic fibroblasts fuel tumor growth (via L-lactate, a high-energy mitochondrial fuel), MSF fibroblasts significantly increased tumor growth, by up to 4-fold. Mechanistic dissection of the MSF signaling pathway indicated that Cdc42 lies downstream of MSF and fibroblast activation. In accordance with this notion, Cdc42 overexpression in immortalized fibroblasts was sufficient to drive myofibroblast differentiation, to provoke a shift towards glycolytic metabolism and to promote tumor growth by up to 2-fold. In conclusion, the MSF/Cdc42/NFκB signaling cascade may be a critical druggable target in preventing "Warburg-like" cancer metabolism in tumor-associated fibroblasts. Thus, MSF functions in the metabolic remodeling of the tumor microenvironment by metabolically reprogramming cancer-associated fibroblasts toward glycolytic metabolism.

  16. Transcriptional Control of Somatic Cell Reprogramming.

    PubMed

    Xu, Yan; Zhang, Meng; Li, Wenjuan; Zhu, Xihua; Bao, Xichen; Qin, Baoming; Hutchins, Andrew P; Esteban, Miguel A

    2016-04-01

    Somatic cells and pluripotent cells display remarkable differences in most aspects of cell function. Accordingly, somatic cell reprogramming by exogenous factors requires comprehensive changes in gene transcription to induce a forced pluripotent state, which is encompassed by a simultaneous transformation of the epigenome. Nevertheless, how the reprogramming factors and other endogenous regulators coordinate to suppress the somatic cell gene program and activate the pluripotency gene network, and why the conversion is multi-phased and lengthy, remain enigmatic. We summarize the current knowledge of transcriptional regulation in somatic cell reprogramming, and highlight new perspectives that may help to reshape existing paradigms.

  17. Somatic oxidative bioenergetics transitions into pluripotency-dependent glycolysis to facilitate nuclear reprogramming.

    PubMed

    Folmes, Clifford D L; Nelson, Timothy J; Martinez-Fernandez, Almudena; Arrell, D Kent; Lindor, Jelena Zlatkovic; Dzeja, Petras P; Ikeda, Yasuhiro; Perez-Terzic, Carmen; Terzic, Andre

    2011-08-03

    The bioenergetics of somatic dedifferentiation into induced pluripotent stem cells remains largely unknown. Here, stemness factor-mediated nuclear reprogramming reverted mitochondrial networks into cristae-poor structures. Metabolomic footprinting and fingerprinting distinguished derived pluripotent progeny from parental fibroblasts according to elevated glucose utilization and production of glycolytic end products. Temporal sampling demonstrated glycolytic gene potentiation prior to induction of pluripotent markers. Functional metamorphosis of somatic oxidative phosphorylation into acquired pluripotent glycolytic metabolism conformed to an embryonic-like archetype. Stimulation of glycolysis promoted, while blockade of glycolytic enzyme activity blunted, reprogramming efficiency. Metaboproteomics resolved upregulated glycolytic enzymes and downregulated electron transport chain complex I subunits underlying cell fate determination. Thus, the energetic infrastructure of somatic cells transitions into a required glycolytic metabotype to fuel induction of pluripotency.

  18. Transcription factors that control inner ear development and their potential for transdifferentiation and reprogramming.

    PubMed

    Schimmang, Thomas

    2013-03-01

    Transcription factors (TFs) participate during various processes throughout inner ear development such as induction, morphogenesis and determination of cell fate and differentiation. The analysis of mouse mutants has been essential to define the requirement of different members of TF families during these processes. Next to their roles during normal development TFs have also been tested for their capacity to induce differentiation or reprogram cells upon misexpression. Recently the capacity of TFs to transdifferentiate easily accessible cells such as fibroblasts to highly specialized cell types has opened a new pathway for regenerative therapies. In this review the influence of TFs acting during different phases and processes of inner ear development will be summarized. A special focus will be given to TFs with a potential to reprogram or transdifferentiate cells to sensory cell types of the inner ear such as hair cells or neurons and thus may form part of future protocols directed to generate replacement cells in a clinical context.

  19. Coaxial atomizer liquid intact lengths

    NASA Technical Reports Server (NTRS)

    Eroglu, Hasan; Chigier, Norman; Farago, Zoltan

    1991-01-01

    Average intact lengths of round liquid jets generated by airblast coaxial atomizer were measured from over 1500 photographs. The intact lengths were studied over a jet Reynolds number range of 18,000 and Weber number range of 260. Results are presented for two different nozzle geometries. The intact lengths were found to be strongly dependent on Re and We numbers. An empirical equation was derived as a function of these parameters. A comparison of the intact lengths for round jets and flat sheets shows that round jets generate shorter intact lengths.

  20. Stem cell reprogramming: A 3D boost

    NASA Astrophysics Data System (ADS)

    Abilez, Oscar J.; Wu, Joseph C.

    2016-03-01

    Biophysical factors in an optimized three-dimensional microenvironment enhance the reprogramming efficiency of human somatic cells into pluripotent stem cells when compared to traditional cell-culture substrates.

  1. Historical origins of transdifferentiation and reprogramming.

    PubMed

    Graf, Thomas

    2011-12-02

    Transcription factor-induced reprogramming of specialized cells into other cell types and to pluripotency has revolutionized our thinking about cell plasticity, differentiation, and stem cells. The recent advances in this area were enabled by the confluence of a number of experimental breakthroughs that took place over the past 60 years. In this article, I give a historical and personal perspective of the events that set the stage for our current understanding of cellular reprogramming.

  2. (Photosynthesis in intact plants)

    SciTech Connect

    Not Available

    1990-01-01

    Progress in the two years since the last renewal application has been excellent. We have made substantial contributions on both main fronts of the projects, and are particularly happy with the progress of our research on intact plants. The approach of basing our field work on a sound foundation of laboratory studies has enabled is to use methods which provide unambiguous assays of well characterized reactions. We have also made excellent progress in several laboratory studies which will have direct applications in future field work, and have introduced to the laboratory a range of molecular genetics techniques which will allow us to explore new options in the attempt to understand function at the level of molecular structure.

  3. Plasmid-Based Generation of Induced Neural Stem Cells from Adult Human Fibroblasts

    PubMed Central

    Capetian, Philipp; Azmitia, Luis; Pauly, Martje G.; Krajka, Victor; Stengel, Felix; Bernhardi, Eva-Maria; Klett, Mariana; Meier, Britta; Seibler, Philip; Stanslowsky, Nancy; Moser, Andreas; Knopp, Andreas; Gillessen-Kaesbach, Gabriele; Nikkhah, Guido; Wegner, Florian; Döbrössy, Máté; Klein, Christine

    2016-01-01

    Direct reprogramming from somatic to neural cell types has become an alternative to induced pluripotent stem cells. Most protocols employ viral expression systems, posing the risk of random genomic integration. Recent developments led to plasmid-based protocols, lowering this risk. However, these protocols either relied on continuous presence of a variety of small molecules or were only able to reprogram murine cells. We therefore established a reprogramming protocol based on vectors containing the Epstein-Barr virus (EBV)-derived oriP/EBNA1 as well as the defined expression factors Oct3/4, Sox2, Klf4, L-myc, Lin28, and a small hairpin directed against p53. We employed a defined neural medium in combination with the neurotrophins bFGF, EGF and FGF4 for cultivation without the addition of small molecules. After reprogramming, cells demonstrated a temporary increase in the expression of endogenous Oct3/4. We obtained induced neural stem cells (iNSC) 30 days after transfection. In contrast to previous results, plasmid vectors as well as a residual expression of reprogramming factors remained detectable in all cell lines. Cells showed a robust differentiation into neuronal (72%) and glial cells (9% astrocytes, 6% oligodendrocytes). Despite the temporary increase of pluripotency-associated Oct3/4 expression during reprogramming, we did not detect pluripotent stem cells or non-neural cells in culture (except occasional residual fibroblasts). Neurons showed electrical activity and functional glutamatergic synapses. Our results demonstrate that reprogramming adult human fibroblasts to iNSC by plasmid vectors and basic neural medium without small molecules is possible and feasible. However, a full set of pluripotency-associated transcription factors may indeed result in the acquisition of a transient (at least partial) pluripotent intermediate during reprogramming. In contrast to previous reports, the EBV-based plasmid system remained present and active inside the cells at

  4. Pioneer transcription factors in cell reprogramming.

    PubMed

    Iwafuchi-Doi, Makiko; Zaret, Kenneth S

    2014-12-15

    A subset of eukaryotic transcription factors possesses the remarkable ability to reprogram one type of cell into another. The transcription factors that reprogram cell fate are invariably those that are crucial for the initial cell programming in embryonic development. To elicit cell programming or reprogramming, transcription factors must be able to engage genes that are developmentally silenced and inappropriate for expression in the original cell. Developmentally silenced genes are typically embedded in "closed" chromatin that is covered by nucleosomes and not hypersensitive to nuclease probes such as DNase I. Biochemical and genomic studies have shown that transcription factors with the highest reprogramming activity often have the special ability to engage their target sites on nucleosomal DNA, thus behaving as "pioneer factors" to initiate events in closed chromatin. Other reprogramming factors appear dependent on pioneer factors for engaging nucleosomes and closed chromatin. However, certain genomic domains in which nucleosomes are occluded by higher-order chromatin structures, such as in heterochromatin, are resistant to pioneer factor binding. Understanding the means by which pioneer factors can engage closed chromatin and how heterochromatin can prevent such binding promises to advance our ability to reprogram cell fates at will and is the topic of this review.

  5. Matrix identity and tractional forces influence indirect cardiac reprogramming

    NASA Astrophysics Data System (ADS)

    Kong, Yen P.; Carrion, Bita; Singh, Rahul K.; Putnam, Andrew J.

    2013-12-01

    Heart regeneration through in vivo cardiac reprogramming has been demonstrated as a possible regenerative strategy. While it has been reported that cardiac reprogramming in vivo is more efficient than in vitro, the influence of the extracellular microenvironment on cardiac reprogramming remains incompletely understood. This understanding is necessary to improve the efficiency of cardiac reprogramming in order to implement this strategy successfully. Here we have identified matrix identity and cell-generated tractional forces as key determinants of the dedifferentiation and differentiation stages during reprogramming. Cell proliferation, matrix mechanics, and matrix microstructure are also important, but play lesser roles. Our results suggest that the extracellular microenvironment can be optimized to enhance cardiac reprogramming.

  6. Epigenetic landscapes explain partially reprogrammed cells and identify key reprogramming gene

    NASA Astrophysics Data System (ADS)

    Lang, Alex; Li, Hu; Collins, James; Mehta, Pankaj

    2013-03-01

    A common metaphor for describing development is a rugged epigenetic landscape where cell fates are represented as attracting valleys resulting from a complex regulatory network. Here, we introduce a framework for explicitly constructing epigenetic landscapes that combines genomic data with techniques from physics, specifically Hopfield neural networks. Each cell fate is a dynamic attractor, yet cells can change fate in response to external signals. Our model suggests that partially reprogrammed cells (cells found in reprogramming experiments but not in vivo) are a natural consequence of high-dimensional landscapes and predicts that partially reprogrammed cells should be hybrids that coexpress genes from multiple cell fates. We verify this prediction by reanalyzing existing data sets. Our model reproduces known reprogramming protocols and identifies candidate transcription factors for reprogramming to novel cell fates, suggesting epigenetic landscapes are a powerful paradigm for understanding cellular identity.

  7. The physics of intact capture

    NASA Technical Reports Server (NTRS)

    Tsou, Peter; Griffiths, D. J.; Albee, A. L.

    1994-01-01

    The ability to capture projectiles intact at hypervelocities in underdense media open a new area of study in physics. Underdense material behaves markedly different than solid, liquid, or gas upon hypervelocity impact. This new phenomenon enables applications in science that would either not be possible or would be very costly by other means. This phenomenon has been fully demonstrated in the laboratory and validated in space. Even more interesting is the fact that this hypervelocity intact capture was accomplished passively. A better understanding of the physics of intact capture will lead to improvements in intact capture. A collection of physical observations of this phenomenon is presented here.

  8. Reprogramming adult dermis to a neonatal state through epidermal activation of β-catenin

    PubMed Central

    Collins, Charlotte A.; Kretzschmar, Kai; Watt, Fiona M.

    2011-01-01

    Hair follicle formation depends on reciprocal epidermal-dermal interactions and occurs during skin development, but not in adult life. This suggests that the properties of dermal fibroblasts change during postnatal development. To examine this, we used a PdgfraEGFP mouse line to isolate GFP-positive fibroblasts from neonatal skin, adult telogen and anagen skin and adult skin in which ectopic hair follicles had been induced by transgenic epidermal activation of β-catenin (EF skin). We also isolated epidermal cells from each mouse. The gene expression profile of EF epidermis was most similar to that of anagen epidermis, consistent with activation of β-catenin signalling. By contrast, adult dermis with ectopic hair follicles more closely resembled neonatal dermis than adult telogen or anagen dermis. In particular, genes associated with mitosis were upregulated and extracellular matrix-associated genes were downregulated in neonatal and EF fibroblasts. We confirmed that sustained epidermal β-catenin activation stimulated fibroblasts to proliferate to reach the high cell density of neonatal skin. In addition, the extracellular matrix was comprehensively remodelled, with mature collagen being replaced by collagen subtypes normally present only in developing skin. The changes in proliferation and extracellular matrix composition originated from a specific subpopulation of fibroblasts located beneath the sebaceous gland. Our results show that adult dermis is an unexpectedly plastic tissue that can be reprogrammed to acquire the molecular, cellular and structural characteristics of neonatal dermis in response to cues from the overlying epidermis. PMID:22031549

  9. Mitochondrial fusion by pharmacological manipulation impedes somatic cell reprogramming to pluripotency: New insight into the role of mitophagy in cell stemness

    PubMed Central

    Vazquez-Martin, Alejandro; Cufí, Sílvia; Corominas-Faja, Bruna; Oliveras-Ferraros, Cristina; Vellon, Luciano; Menendez, Javier A.

    2012-01-01

    Recent studies have suggested a pivotal role for autophagy in stem cell maintenance and differentiation. Reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) has been also suggested to bio-energetically take advantage of mitochondrial autophagy (mitophagy). We have preliminary addressed how mitophagy might play a role in the regulation of induced pluripotency using mdivi-1 (for mitochondrial division inhibitor), a highly efficacious small molecule that selectively inhibits the self-assembly of DRP1, a member of the dynamin family of large GTPases that mediates mitochondrial fission. At mdivi-1 concentrations that rapidly induced the formation of mitochondrial net-like or collapsed perinuclear mitochondrial structures, we observed that the reprogramming efficiency of mouse embryonic fibroblasts transduced with the Yamanaka three-factor cocktail (OCT4, KLF4, and SOX2) is drastically reduced by more than 95%. Treatment of MEFs with mdivi-1 at the early stages of reprogramming before the appearance of iPSC colonies was sufficient to completely inhibit somatic cell reprogramming. Therefore, the observed effects on reprogramming efficiencies were due likely to the inhibition of the process of reprogramming itself and not to an impairment of iPSC colony survival or growth. Moreover, the typical morphology of established iPSC colonies with positive alkaline phosphatase staining was negatively affected by mdivi-1 exposure. In the presence of mdivi-1, the colony morphology of the iPSCs was lost, and they somewhat resembled fibroblasts. The alkaline phosphatase staining was also significantly reduced, a finding that is indicative of differentiation. Our current findings provide new insight into how mitochondrial division is integrated into the reprogramming factors-driven transcriptional network that specifies the unique pluripotency of stem cells. PMID:22713507

  10. Reprogramming T cell Lymphocytes to Induced Pluripotent Stem Cells

    NASA Astrophysics Data System (ADS)

    Bared, Kalia

    The discovery of induced pluripotent stem cells (iPSC) provided a novel technology for the study of development and pharmacology and complement embryonic stem cells (ES) for cell therapy applications. Though iPSC are derived from adult tissue they are comparable to ES cells in their behavior; multi-lineage differentiation and self-renewal. This makes iPSC research appealing because they can be studied in great detail and expanded in culture broadly. Fibroblasts were the first cell type reprogrammed to an iPSC using a retrovirus vector, since then alternative cell types including lymphocytes have been used to generate iPSC. Different types of vectors have also been developed to enhance iPSC formation and quality. However, specific T lymphocyte subsets have not been shown to reprogram to a pluripotent state to date. Here, we proposed to derive iPSC from peripheral blood effector and central memory T cells, reasoning that the resultant iPSC will maintain the epigenetic memory of a T lymphocyte, including the T cell receptor (TCR) gene rearrangement. This epigenetic memory will enable the differentiation and expansion of T cell iPSC into professional T cells containing a specific TCR. These could then be used for cell therapy to target specific antigens, as well as to improve culture techniques to expand T cells in vitro. We studied different gene delivery methods to derive iPSC from different types of T lymphocytes. We assessed the viability of viral transduction using flow cytometry to detect green fluorescent marker contained in the viral construct and quantitative real time polymerase chain reaction (qRT-PCR) to detect Oct4, Klf4, Sox2, and c-Myc gene expression. Our results demonstrate that the Sendai virus construct is the most feasible platform to reprogram T lymphocytes. We anticipate that this platform will provide an efficient and safe approach to derive iPSC from different T cell subsets, including memory T cells.

  11. Reprogramming of the chick retinal pigmented epithelium after retinal injury

    PubMed Central

    2014-01-01

    Background One of the promises in regenerative medicine is to regenerate or replace damaged tissues. The embryonic chick can regenerate its retina by transdifferentiation of the retinal pigmented epithelium (RPE) and by activation of stem/progenitor cells present in the ciliary margin. These two ways of regeneration occur concomitantly when an external source of fibroblast growth factor 2 (FGF2) is present after injury (retinectomy). During the process of transdifferentiation, the RPE loses its pigmentation and is reprogrammed to become neuroepithelium, which differentiates to reconstitute the different cell types of the neural retina. Somatic mammalian cells can be reprogrammed to become induced pluripotent stem cells by ectopic expression of pluripotency-inducing factors such as Oct4, Sox2, Klf4, c-Myc and in some cases Nanog and Lin-28. However, there is limited information concerning the expression of these factors during natural regenerative processes. Organisms that are able to regenerate their organs could share similar mechanisms and factors with the reprogramming process of somatic cells. Herein, we investigate the expression of pluripotency-inducing factors in the RPE after retinectomy (injury) and during transdifferentiation in the presence of FGF2. Results We present evidence that upon injury, the quiescent (p27Kip1+/BrdU-) RPE cells transiently dedifferentiate and express sox2, c-myc and klf4 along with eye field transcriptional factors and display a differential up-regulation of alternative splice variants of pax6. However, this transient process of dedifferentiation is not sustained unless FGF2 is present. We have identified lin-28 as a downstream target of FGF2 during the process of retina regeneration. Moreover, we show that overexpression of lin-28 after retinectomy was sufficient to induce transdifferentiation of the RPE in the absence of FGF2. Conclusion These findings delineate in detail the molecular changes that take place in the RPE during

  12. Epigenetic reprogramming in the porcine germ line

    PubMed Central

    2011-01-01

    Background Epigenetic reprogramming is critical for genome regulation during germ line development. Genome-wide demethylation in mouse primordial germ cells (PGC) is a unique reprogramming event essential for erasing epigenetic memory and preventing the transmission of epimutations to the next generation. In addition to DNA demethylation, PGC are subject to a major reprogramming of histone marks, and many of these changes are concurrent with a cell cycle arrest in the G2 phase. There is limited information on how well conserved these events are in mammals. Here we report on the dynamic reprogramming of DNA methylation at CpGs of imprinted loci and DNA repeats, and the global changes in H3K27me3 and H3K9me2 in the developing germ line of the domestic pig. Results Our results show loss of DNA methylation in PGC colonizing the genital ridges. Analysis of IGF2-H19 regulatory region showed a gradual demethylation between E22-E42. In contrast, DMR2 of IGF2R was already demethylated in male PGC by E22. In females, IGF2R demethylation was delayed until E29-31, and was de novo methylated by E42. DNA repeats were gradually demethylated from E25 to E29-31, and became de novo methylated by E42. Analysis of histone marks showed strong H3K27me3 staining in migratory PGC between E15 and E21. In contrast, H3K9me2 signal was low in PGC by E15 and completely erased by E21. Cell cycle analysis of gonadal PGC (E22-31) showed a typical pattern of cycling cells, however, migrating PGC (E17) showed an increased proportion of cells in G2. Conclusions Our study demonstrates that epigenetic reprogramming occurs in pig migratory and gonadal PGC, and establishes the window of time for the occurrence of these events. Reprogramming of histone H3K9me2 and H3K27me3 detected between E15-E21 precedes the dynamic DNA demethylation at imprinted loci and DNA repeats between E22-E42. Our findings demonstrate that major epigenetic reprogramming in the pig germ line follows the overall dynamics shown in

  13. Dysfunctional mitochondrial fission impairs cell reprogramming.

    PubMed

    Prieto, Javier; León, Marian; Ponsoda, Xavier; García-García, Francisco; Bort, Roque; Serna, Eva; Barneo-Muñoz, Manuela; Palau, Francesc; Dopazo, Joaquín; López-García, Carlos; Torres, Josema

    2016-12-01

    We have recently shown that mitochondrial fission is induced early in reprogramming in a Drp1-dependent manner; however, the identity of the factors controlling Drp1 recruitment to mitochondria was unexplored. To investigate this, we used a panel of RNAi targeting factors involved in the regulation of mitochondrial dynamics and we observed that MiD51, Gdap1 and, to a lesser extent, Mff were found to play key roles in this process. Cells derived from Gdap1-null mice were used to further explore the role of this factor in cell reprogramming. Microarray data revealed a prominent down-regulation of cell cycle pathways in Gdap1-null cells early in reprogramming and cell cycle profiling uncovered a G2/M growth arrest in Gdap1-null cells undergoing reprogramming. High-Content analysis showed that this growth arrest was DNA damage-independent. We propose that lack of efficient mitochondrial fission impairs cell reprogramming by interfering with cell cycle progression in a DNA damage-independent manner.

  14. Oncometabolic Nuclear Reprogramming of Cancer Stemness

    PubMed Central

    Menendez, Javier A.; Corominas-Faja, Bruna; Cuyàs, Elisabet; García, María G.; Fernández-Arroyo, Salvador; Fernández, Agustín F.; Joven, Jorge; Fraga, Mario F.; Alarcón, Tomás

    2016-01-01

    Summary By impairing histone demethylation and locking cells into a reprogramming-prone state, oncometabolites can partially mimic the process of induced pluripotent stem cell generation. Using a systems biology approach, combining mathematical modeling, computation, and proof-of-concept studies with live cells, we found that an oncometabolite-driven pathological version of nuclear reprogramming increases the speed and efficiency of dedifferentiating committed epithelial cells into stem-like states with only a minimal core of stemness transcription factors. Our biomathematical model, which introduces nucleosome modification and epigenetic regulation of cell differentiation genes to account for the direct effects of oncometabolites on nuclear reprogramming, demonstrates that oncometabolites markedly lower the “energy barriers” separating non-stem and stem cell attractors, diminishes the average time of nuclear reprogramming, and increases the size of the basin of attraction of the macrostate occupied by stem cells. These findings establish the concept of oncometabolic nuclear reprogramming of stemness as a bona fide metabolo-epigenetic mechanism for generation of cancer stem-like cells. PMID:26876667

  15. GM-CSF and MEF-conditioned media support feeder-free reprogramming of mouse granulocytes to iPS cells.

    PubMed

    Firas, Jaber; Liu, Xiaodong; Nefzger, Christian M; Polo, Jose M

    2014-06-01

    Induced pluripotent stem cells (iPSCs) are characterised by their ability to differentiate into any cell type of the body. Accordingly, iPSCs possess immense potential for disease modelling, pharmaceutical screening and autologous cell therapies. The most common source of iPSCs derivation is skin fibroblasts. However, from a clinical point of view, skin fibroblasts may not be ideal, as invasive procedures such as skin biopsies are required for their extraction. Moreover, fibroblasts are highly heterogeneous with a poorly defined developmental pathway, which makes studying reprogramming mechanistics difficult. Granulocytes, on the other hand, are easily obtainable, their developmental pathway has been extensively studied and fluorescence activated cell sorting allows for the isolation of these cells at high purity; thus iPSCs derivation from granulocytes could provide an alternative to fibroblast-derived iPSCs. Previous studies succeeded in producing iPSC colonies from mouse granulocytes but with the use of a mitotically inactivated feeder layer, restricting their use for studying reprogramming mechanistics. As granulocytes display poor survival under culture conditions, we investigated the influence of haematopoietic cytokines to stabilise this cell type in vitro and allow for reprogramming in the absence of a feeder layer. Our results show that treatment with MEF-conditioned media and/or initial exposure to GM-CSF allows for reprogramming of granulocytes under feeder-free conditions. This work can serve as a basis for future work aimed at dissecting the reprogramming mechanism as well as obtaining large numbers of iPSCs from a clinically relevant cell source.

  16. Space research with intact organisms

    NASA Technical Reports Server (NTRS)

    Phillips, Robert W.; Haddy, Francis J.

    1992-01-01

    Effects of space exposure on intact organisms are briefly reviewed, and examples of future experiments that might provide new information on the role of gravity in the evolution of life are suggested. It is noted that long term experiments with intact plant and animals for studying gravitational thresholds will provide important new insights.

  17. Small molecules increase direct neural conversion of human fibroblasts

    PubMed Central

    Pfisterer, Ulrich; Ek, Fredrik; Lang, Stefan; Soneji, Shamit; Olsson, Roger; Parmar, Malin

    2016-01-01

    The generation of human induced neurons (hiNs) via exogenous delivery of neural transcription factors represents a novel technique to obtain disease and patient specific neurons. These cells have the potential to be used for disease modeling, diagnostics and drug screening, and also to be further developed for brain repair. In the present study, we utilized hiNs to develop an unbiased screening assay for small molecules that increase the conversion efficiency. Using this assay, we screened 307 compounds from five annotated libraries and identified six compounds that were very potent in potentiating the reprogramming process. When combined in an optimal combination and dose, these compounds increased the reprogramming efficiency of human fibroblasts more than 6-fold. Global gene expression and CellNet analysis at different timepoints during the reprogramming process revealed that neuron-specific genes and gene regulatory networks (GRNs) became progressively more activated while converting cells shut down fibroblast-specific GRNs. Further bioinformatics analysis revealed that the addition of the six compound resulted in the accelerated upregulation of a subset of neuronal genes, and also increased expression of genes associated with transcriptional activity and mediation of cellular stress response. PMID:27917895

  18. Notch Inhibition Enhances Cardiac Reprogramming by Increasing MEF2C Transcriptional Activity.

    PubMed

    Abad, Maria; Hashimoto, Hisayuki; Zhou, Huanyu; Morales, Maria Gabriela; Chen, Beibei; Bassel-Duby, Rhonda; Olson, Eric N

    2017-03-14

    Conversion of fibroblasts into functional cardiomyocytes represents a potential means of restoring cardiac function after myocardial infarction, but so far this process remains inefficient and little is known about its molecular mechanisms. Here we show that DAPT, a classical Notch inhibitor, enhances the conversion of mouse fibroblasts into induced cardiac-like myocytes by the transcription factors GATA4, HAND2, MEF2C, and TBX5. DAPT cooperates with AKT kinase to further augment this process, resulting in up to 70% conversion efficiency. Moreover, DAPT promotes the acquisition of specific cardiomyocyte features, substantially increasing calcium flux, sarcomere structure, and the number of spontaneously beating cells. Transcriptome analysis shows that DAPT induces genetic programs related to muscle development, differentiation, and excitation-contraction coupling. Mechanistically, DAPT increases binding of the transcription factor MEF2C to the promoter regions of cardiac structural genes. These findings provide mechanistic insights into the reprogramming process and may have important implications for cardiac regeneration therapies.

  19. Optical reprogramming with ultrashort femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Uchugonova, Aisada; Breunig, Hans G.; Batista, Ana; König, Karsten

    2015-03-01

    The use of sub-15 femtosecond laser pulses in stem cell research is explored with particular emphasis on the optical reprogramming of somatic cells. The reprogramming of somatic cells into induced pluripotent stem (iPS) cells can be evoked through the ectopic expression of defined transcription factors. Conventional approaches utilize retro/lenti-viruses to deliver genes/transcription factors as well as to facilitate the integration of transcription factors into that of the host genome. However, the use of viruses may result in insertional mutations caused by the random integration of genes and as a result, this may limit the use within clinical applications due to the risk of the formation of cancer. In this study, a new approach is demonstrated in realizing non-viral reprogramming through the use of ultrashort laser pulses, to introduce transcription factors into the cell so as to generate iPS cells.

  20. An integrative analysis of reprogramming in human isogenic system identified a clone selection criterion.

    PubMed

    Shutova, Maria V; Surdina, Anastasia V; Ischenko, Dmitry S; Naumov, Vladimir A; Bogomazova, Alexandra N; Vassina, Ekaterina M; Alekseev, Dmitry G; Lagarkova, Maria A; Kiselev, Sergey L

    2016-01-01

    The pluripotency of newly developed human induced pluripotent stem cells (iPSCs) is usually characterized by physiological parameters; i.e., by their ability to maintain the undifferentiated state and to differentiate into derivatives of the 3 germ layers. Nevertheless, a molecular comparison of physiologically normal iPSCs to the "gold standard" of pluripotency, embryonic stem cells (ESCs), often reveals a set of genes with different expression and/or methylation patterns in iPSCs and ESCs. To evaluate the contribution of the reprogramming process, parental cell type, and fortuity in the signature of human iPSCs, we developed a complete isogenic reprogramming system. We performed a genome-wide comparison of the transcriptome and the methylome of human isogenic ESCs, 3 types of ESC-derived somatic cells (fibroblasts, retinal pigment epithelium and neural cells), and 3 pairs of iPSC lines derived from these somatic cells. Our analysis revealed a high input of stochasticity in the iPSC signature that does not retain specific traces of the parental cell type and reprogramming process. We showed that 5 iPSC clones are sufficient to find with 95% confidence at least one iPSC clone indistinguishable from their hypothetical isogenic ESC line. Additionally, on the basis of a small set of genes that are characteristic of all iPSC lines and isogenic ESCs, we formulated an approach of "the best iPSC line" selection and confirmed it on an independent dataset.

  1. NRF2 Orchestrates the Metabolic Shift during Induced Pluripotent Stem Cell Reprogramming

    PubMed Central

    Hawkins, Kate E.; Joy, Shona; Delhove, Juliette M.K.M.; Kotiadis, Vassilios N.; Fernandez, Emilio; Fitzpatrick, Lorna M.; Whiteford, James R.; King, Peter J.; Bolanos, Juan P.; Duchen, Michael R.; Waddington, Simon N.; McKay, Tristan R.

    2016-01-01

    Summary The potential of induced pluripotent stem cells (iPSCs) in disease modeling and regenerative medicine is vast, but current methodologies remain inefficient. Understanding the cellular mechanisms underlying iPSC reprogramming, such as the metabolic shift from oxidative to glycolytic energy production, is key to improving its efficiency. We have developed a lentiviral reporter system to assay longitudinal changes in cell signaling and transcription factor activity in living cells throughout iPSC reprogramming of human dermal fibroblasts. We reveal early NF-κB, AP-1, and NRF2 transcription factor activation prior to a temporal peak in hypoxia inducible factor α (HIFα) activity. Mechanistically, we show that an early burst in oxidative phosphorylation and elevated reactive oxygen species generation mediates increased NRF2 activity, which in turn initiates the HIFα-mediated glycolytic shift and may modulate glucose redistribution to the pentose phosphate pathway. Critically, inhibition of NRF2 by KEAP1 overexpression compromises metabolic reprogramming and results in reduced efficiency of iPSC colony formation. PMID:26904936

  2. Roadmap to cellular reprogramming--manipulating transcriptional networks with DNA, RNA, proteins and small molecules.

    PubMed

    Wörsdörfer, P; Thier, M; Kadari, A; Edenhofer, F

    2013-06-01

    Recent reports demonstrate that the plasticity of mammalian somatic cells is much higher than previously assumed and that ectopic expression of transcription factors may have the potential to induce the conversion of any cell type into another. Fibroblast cells can be converted into embryonic stem cell-like cells, neural cells, cardiomyocytes, macrophage-like cells as well as blood progenitors. Additionally, the conversion of astrocytes into neurons or neural stem cells into monocytes has been demonstrated. Nowadays, in the era of systems biology, continuously growing holistic data sets are providing increasing insights into core transcriptional networks and cellular signaling pathways. This knowledge enables cell biologists to understand how cellular fate is determined and how it could be manipulated. As a consequence for biomedical applications, it might be soon possible to convert patient specific somatic cells directly into desired transplantable other cell types. The clinical value, however, of such reprogrammed cells is currently limited due to the invasiveness of methods applied to induce reprogramming factor activity. This review will focus on experimental strategies to ectopically induce cell fate modulators. We will emphasize those strategies that enable efficient and robust overexpression of transcription factors by minimal genetic alterations of the host genome. Furthermore, we will discuss procedures devoid of any genomic manipulation, such as the direct delivery of mRNA, proteins, or the use of small molecules. By this, we aim to give a comprehensive overview on state of the art techniques that harbor the potential to generate safe reprogrammed cells for clinical applications.

  3. Oct4-enhanced green fluorescent protein transgenic pigs: a new large animal model for reprogramming studies.

    PubMed

    Nowak-Imialek, Monika; Kues, Wilfried A; Petersen, Bjoern; Lucas-Hahn, Andrea; Herrmann, Doris; Haridoss, Srividyameena; Oropeza, Marianne; Lemme, Erika; Schöler, Hans R; Carnwath, Joseph W; Niemann, Heiner

    2011-09-01

    The domesticated pig has emerged as an important tool for development of surgical techniques, advancement of xenotransplantation, creation of important disease models, and preclinical testing of novel cell therapies. However, germ line-competent pluripotent porcine stem cells have not yet been derived. This has been a major obstacle to genetic modification of pigs. The transcription factor Oct4 is essential for the maintenance of pluripotency and for reprogramming somatic cells to a pluripotent state. Here, we report the production of transgenic pigs carrying an 18 kb genomic sequence of the murine Oct4 gene fused to the enhanced green fluorescent protein (EGFP) cDNA (OG2 construct) to allow identification of pluripotent cells by monitoring Oct4 expression by EGFP fluorescence. Eleven viable transgenic piglets were produced by somatic cell nuclear transfer. Expression of the EGFP reporter construct was confined to germ line cells, the inner cell mass and trophectoderm of blastocysts, and testicular germ cells. Reprogramming of fibroblasts from these animals by fusion with pluripotent murine embryonic stem cells or viral transduction with human OCT4, SOX2, KLF4, and c-MYC cDNAs resulted in Oct4-EGFP reactivation. The OG2 pigs have thus proved useful for monitoring reprogramming and the induction and maintenance of pluripotency in porcine cells. In conclusion, the OG2 transgenic pigs are a new large animal model for studying the derivation and maintenance of pluripotent cells, and will be valuable for the development of cell therapy.

  4. Targeted alternative splicing of TAF4: a new strategy for cell reprogramming

    PubMed Central

    Kazantseva, Jekaterina; Sadam, Helle; Neuman, Toomas; Palm, Kaia

    2016-01-01

    Reprogramming of somatic cells has become a versatile tool for biomedical research and for regenerative medicine. In the current study, we show that manipulating alternative splicing (AS) is a highly potent strategy to produce cells for therapeutic applications. We demonstrate that silencing of hTAF4-TAFH activity of TAF4 converts human facial dermal fibroblasts to melanocyte-like (iMel) cells. iMel cells produce melanin and express microphthalmia-associated transcription factor (MITF) and its target genes at levels comparable to normal melanocytes. Reprogramming of melanoma cells by manipulation with hTAF4-TAFH activity upon TAFH RNAi enforces cell differentiation towards chondrogenic pathway, whereas ectoptic expression of TAF4 results in enhanced multipotency and neural crest-like features in melanoma cells. In both cell states, iMels and cancer cells, hTAF4-TAFH activity controls migration by supporting E- to N-cadherin switches. From our data, we conclude that targeted splicing of hTAF4-TAFH coordinates AS of other TFIID subunits, underscoring the role of TAF4 in synchronised changes of Pol II complex composition essential for efficient cellular reprogramming. Taken together, targeted AS of TAF4 provides a unique strategy for generation of iMels and recapitulating stages of melanoma progression. PMID:27499390

  5. Effectiveness of intact capture media

    SciTech Connect

    Tsou, P.; Aubert, J.; Brownlee, D.; Hrubesh, L.; Williams, J.; Albee, A.

    1989-01-01

    The possibility of capturing cosmic dust at hypervelocity has been demonstrated in the laboratory and in the unintended Solar Max spacecraft. This technology will enable a comet coma sample return mission and be important for the earth orbital cosmic dust collection mission, i.e., the Space Station Cosmic Dust Collection Facility. Since the only controllable factor in an intact capture of cosmic dust is the capturing medium, characterizing the effectiveness and properties of available capture media would be very important in the development of the technique for capturing hypervelocity cosmic dust intact. We have evaluated various capture underdense media for the relative effectiveness for intact capture. 2 refs., 2 figs.

  6. Epigenetic Landscapes Explain Partially Reprogrammed Cells and Identify Key Reprogramming Genes

    PubMed Central

    Lang, Alex H.; Li, Hu; Collins, James J.; Mehta, Pankaj

    2014-01-01

    A common metaphor for describing development is a rugged “epigenetic landscape” where cell fates are represented as attracting valleys resulting from a complex regulatory network. Here, we introduce a framework for explicitly constructing epigenetic landscapes that combines genomic data with techniques from spin-glass physics. Each cell fate is a dynamic attractor, yet cells can change fate in response to external signals. Our model suggests that partially reprogrammed cells are a natural consequence of high-dimensional landscapes, and predicts that partially reprogrammed cells should be hybrids that co-express genes from multiple cell fates. We verify this prediction by reanalyzing existing datasets. Our model reproduces known reprogramming protocols and identifies candidate transcription factors for reprogramming to novel cell fates, suggesting epigenetic landscapes are a powerful paradigm for understanding cellular identity. PMID:25122086

  7. Targeted release of transcription factors for cell reprogramming by a natural micro-syringe.

    PubMed

    Berthoin, Lionel; Toussaint, Bertrand; Garban, Frédéric; Le Gouellec, Audrey; Caulier, Benjamin; Polack, Benoît; Laurin, David

    2016-11-20

    Ectopic expression of defined transcription factors (TFs) for cell fate handling has proven high potential interest in reprogramming differentiated cells, in particular for regenerative medicine, ontogenesis study and cell based modelling. Pluripotency or transdifferentiation induction as TF mediated differentiation is commonly produced by transfer of genetic information with safety concerns. The direct delivery of proteins could represent a safer alternative but still needs significant advances to be efficient. We have successfully developed the direct delivery of proteins by an attenuated bacterium with a type 3 secretion system that does not require challenging and laborious steps for production and purification of recombinant molecules. Here we show that this natural micro-syringe is able to inject TFs to primary human fibroblasts and cord blood CD34(+) hematopoietic stem cells. The signal sequence for vectorization of the TF Oct4 has no effect on DNA binding to its nucleic target. As soon as one hour after injection, vectorized TFs are detectable in the nucleus. The injection process is not associated with toxicity and the bacteria can be completely removed from cell cultures. A three days targeted release of Oct4 or Sox2 embryonic TFs results in the induction of the core pluripotency genes expression in fibroblasts and CD34(+) hematopoietic stem cells. This micro-syringe vectorization represents a new strategy for TF delivery and has potential applications for cell fate reprogramming.

  8. Sequential Regulatory Loops as Key Gatekeepers for Neuronal Reprogramming in Human Cells

    PubMed Central

    Xue, Yuanchao; Qian, Hao; Hu, Jing; Zhou, Bing; Zhou, Yu; Hu, Xihao; Karakhanyan, Aziz; Pang, Zhiping; Fu, Xiang-Dong

    2016-01-01

    Direct conversion of somatic cells into neurons holds great promise for regenerative medicine. However, as neuronal conversion is relatively inefficient on human cells compared to mouse cells, it has been unclear what might be key barriers to reprogramming in human cells. We recently elucidated an RNA program mediated by the polypyrimidine tract binding protein PTB to convert mouse embryonic fibroblasts (MEFs) into functional neurons. On human adult fibroblasts (HAFs), however, we unexpectedly find that invoke of the documented PTB-REST-miR-124 loop only generates immature neurons. We now report that the functionality requires sequential inactivation of PTB and the PTB paralog nPTB in HAFs. Inactivation of nPTB triggers another self-enforcing loop essential for neuronal maturation, which comprises nPTB, the transcription factor BRN2, and miR-9. These findings suggest two separate gatekeepers to control neuronal conversion and maturation and consecutively overcoming these gatekeepers enables deterministic reprogramming of HAFs into functional neurons. PMID:27110916

  9. Generation of human iPS cell line SKiPSc1 from healthy Human Neonatal Foreskin Fibroblast cells.

    PubMed

    Alawad, Abdullah; Alhazzaa, Othman; Altuwaijri, Saleh; Alkhrayef, Mohammad; Alagrafi, Faisal; Alhamdan, Ziyad; Alenazi, Abdullah; Alharbi, Sultan; Hammad, Mohamed

    2016-06-25

    The SKiPSc1 induced pluripotent stem (iPS) cell line was generated from Human Neonatal Foreskin Fibroblasts (HNFFs) obtained from a healthy donor infant that were reprogrammed using non-integrating Sendai viral vectors expressing Oct3/4, Sox2, c-Myc, and Klf4.

  10. Blood pressure reprogramming adapter assists signal recording

    NASA Technical Reports Server (NTRS)

    Vick, H. A.

    1967-01-01

    Blood pressure reprogramming adapter separates the two components of a blood pressure signal, a dc pressure signal and an ac Korotkoff sounds signal, so that the Korotkoff sounds are recorded on one channel as received while the dc pressure signal is converted to FM and recorded on a second channel.

  11. Cellular Reprogramming Allows Generation of Autologous Hematopoietic Progenitors From AML Patients That Are Devoid of Patient-Specific Genomic Aberrations.

    PubMed

    Salci, Kyle R; Lee, Jong-Hee; Laronde, Sarah; Dingwall, Steve; Kushwah, Rahul; Fiebig-Comyn, Aline; Leber, Brian; Foley, Ronan; Dal Cin, Arianna; Bhatia, Mickie

    2015-06-01

    Current treatments that use hematopoietic progenitor cell (HPC) transplantation in acute myeloid leukemia (AML) patients substantially reduce the risk of relapse, but are limited by the availability of immune compatible healthy HPCs. Although cellular reprogramming has the potential to provide a novel autologous source of HPCs for transplantation, the applicability of this technology toward the derivation of healthy autologous hematopoietic cells devoid of patient-specific leukemic aberrations from AML patients must first be evaluated. Here, we report the generation of human AML patient-specific hematopoietic progenitors that are capable of normal in vitro differentiation to myeloid lineages and are devoid of leukemia-associated aberration found in matched patient bone marrow. Skin fibroblasts were obtained from AML patients whose leukemic cells possessed a distinct, leukemia-associated aberration, and used to create AML patient-specific induced pluripotent stem cells (iPSCs). Through hematopoietic differentiation of AML patient iPSCs, coupled with cytogenetic interrogation, we reveal that AML patient-specific HPCs possess normal progenitor capacity and are devoid of leukemia-associated mutations. Importantly, in rare patient skin samples that give rise to mosaic fibroblast cultures that continue to carry leukemia-associated mutations; healthy hematopoietic progenitors can also be generated via reprogramming selection. Our findings provide the proof of principle that cellular reprogramming can be applied on a personalized basis to generate healthy HPCs from AML patients, and should further motivate advances toward creating transplantable hematopoietic stem cells for autologous AML therapy.

  12. BMP-SMAD-ID promotes reprogramming to pluripotency by inhibiting p16/INK4A-dependent senescence

    PubMed Central

    Hayashi, Yohei; Hsiao, Edward C.; Sami, Salma; Lancero, Mariselle; Schlieve, Christopher R.; Nguyen, Trieu; Yano, Koyori; Nagahashi, Ayako; Ikeya, Makoto; Matsumoto, Yoshihisa; Nishimura, Ken; Fukuda, Aya; Hisatake, Koji; Tomoda, Kiichiro; Asaka, Isao; Toguchida, Junya; Conklin, Bruce R.; Yamanaka, Shinya

    2016-01-01

    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. PMID:27794120

  13. Behavior of leucine-rich repeat-containing G-protein coupled receptor 5-expressing cells in the reprogramming process.

    PubMed

    Arioka, Yuko; Ito, Hiroyasu; Hirata, Akihiro; Semi, Katsunori; Yamada, Yasuhiro; Seishima, Mitsuru

    2017-02-04

    It remains unclear what cells are proper for the generation of induced pluripotent stem cells (iPSCs). Leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5) is well known as a tissue stem cell and progenitor marker, both of which are reported to be sensitive to reprogramming. In the present study, we examined the reprogramming behavior of Lgr5-expressing cells (Lgr5+ cells). First, we compared reprogramming behavior using mouse Lgr5+ and Lgr5 negative (Lgr5-) hair follicles (HFs). The number of alkaline phosphatase staining-positive cells was lesser in a well of Lgr5+ HFs than in Lgr5- HFs; however, the ratio of Nanog+ SSEA1+ cells in the cell mixture derived from Lgr5+ HFs was much higher than that from Lgr5- HFs. Lgr5+ cells could be induced from mouse embryonic fibroblasts (MEFs) after transduction with Yamanaka factors. As shown in HFs, the progeny of Lgr5+ cells arising from MEFs highly converted into Nanog+ cells and did not form Nanog- colonies. The progeny represented the status of the late reprogramming phase to a higher degree than the nonprogeny. We also confirmed this using human Lg5+ cells. Our findings suggest that the use of Lgr5+ cells will minimize sorting efforts for obtaining superior iPSCs.

  14. Delayed transition to new cell fates during cellular reprogramming.

    PubMed

    Cheng, Xianrui; Lyons, Deirdre C; Socolar, Joshua E S; McClay, David R

    2014-07-15

    In many embryos specification toward one cell fate can be diverted to a different cell fate through a reprogramming process. Understanding how that process works will reveal insights into the developmental regulatory logic that emerged from evolution. In the sea urchin embryo, cells at gastrulation were found to reprogram and replace missing cell types after surgical dissections of the embryo. Non-skeletogenic mesoderm (NSM) cells reprogrammed to replace missing skeletogenic mesoderm cells and animal caps reprogrammed to replace all endomesoderm. In both cases evidence of reprogramming onset was first observed at the early gastrula stage, even if the cells to be replaced were removed earlier in development. Once started however, the reprogramming occurred with compressed gene expression dynamics. The NSM did not require early contact with the skeletogenic cells to reprogram, but the animal cap cells gained the ability to reprogram early in gastrulation only after extended contact with the vegetal halves prior to that time. If the entire vegetal half was removed at early gastrula, the animal caps reprogrammed and replaced the vegetal half endomesoderm. If the animal caps carried morpholinos to either hox11/13b or foxA (endomesoderm specification genes), the isolated animal caps failed to reprogram. Together these data reveal that the emergence of a reprogramming capability occurs at early gastrulation in the sea urchin embryo and requires activation of early specification components of the target tissues.

  15. miR-124-9-9* potentiates Ascl1-induced reprogramming of cultured Müller glia.

    PubMed

    Wohl, Stefanie Gabriele; Reh, Thomas Andrew

    2016-05-01

    The Müller glia of fish provide a source for neuronal regeneration after injury, but they do not do so in mammals. We previously showed that lentiviral gene transfer of the transcription factor Achaete-scute homolog 1 (Ascl1/Mash1) in murine Müller glia cultures resulted in partial reprogramming of the cells to retinal progenitors. The microRNAs (miRNAs) miR-124-9-9* facilitate neuronal reprogramming of fibroblasts, but their role in glia reprogramming has not been reported. The aim of this study was to test whether (1) lentiviral gene transfer of miR-124-9-9* can reprogram Müller glia into retinal neurons and (2) miR-124-9-9* can improve Ascl1-induced reprogramming. Primary Müller glia cultures were generated from postnatal day (P) 11/12 mice, transduced with lentiviral particles, i.e., miR-124-9-9*-RFP, nonsense-RFP, Ascl1-GFP, or GFP-control. Gene expression and immunofluorescence analyses were performed within 3 weeks after infection. 1. Overexpression of miR-124-9-9* induced the expression of the proneural factor Ascl1 and additional markers of neurons, including TUJ1 and MAP2. 2. When Ascl1 and miR-124-9-9* were combined, 50 to 60% of Müller glia underwent neuronal reprogramming, whereas Ascl1 alone results in a 30 to 35% reprogramming rate. 3. Analysis of the miR-124-9-9* treated glial cells showed a reduction in the level of Ctdsp1 and Ptbp1, indicating a critical role for the REST pathway in the repression of neuronal genes in Müller glia. Our data further suggest that miR-124-9-9* and the REST complex may play a role in regulating the reprogramming of Müller glia to progenitors that underlies retinal regeneration in zebrafish.

  16. Neural reprogramming in retinal degenerations

    PubMed Central

    Marc, Robert E.; Jones, Bryan W.; Anderson, James R.; Kinard, Krista; Marshak, David W.; Wilson, John H.; Wensel, Theodore; Lucas, Robert J.

    2008-01-01

    Purpose Early visual defects in degenerative diseases such as retinitis pigmentosa (RP) may arise from phased remodeling of the neural retina. We sought to explore the functional expression of ionotropic (iGluR) and group III, type 6 metabotropic (mGluR6) glutamate receptors in late-stage photoreceptor degenerations. Methods Excitation mapping with organic cations and computational molecular phenotyping were used to determine whether retinal neurons displayed functional glutamate receptor signaling in rodent models of retinal degenerations and a sample of human RP. Results After photoreceptor loss in rodent models of RP, bipolar cells lose mGluR6 and iGluR glutamate-activated currents, while amacrine and ganglion cells retain iGluR-mediated responsivity. Paradoxically, amacrine and ganglion cells show spontaneous iGluR signals in vivo even though bipolar cells lack glutamate-coupled depolarization mechanisms. Cone survival can rescue iGluR expression by OFF bipolar cells. In a case of human RP with cone sparing, iGluR signaling appeared intact, but the numbers of bipolar cells expressing functional iGluRs was double that of normal retina. Conclusions RP triggers permanent loss of bipolar cell glutamate receptor expression, though spontaneous iGluR-mediated signaling by amacrine and ganglion cells implies that such truncated bipolar cells still release glutamate in response to some non-glutamatergic depolarization. Focal cone-sparing can preserve iGluR display by nearby bipolar cells, which may facilitate late-RP photoreceptor transplant attempts. An instance of human RP provides evidence that rod bipolar cell dendrite switching likely triggers new gene expression patterns and may impair cone pathway function. PMID:17591910

  17. On the sensitivity of intact cells to perturbation by ethanol

    SciTech Connect

    Hitzemann, R.; Whitaker-Azmitia, P. ); Dains, K.; Lin, J. )

    1989-01-01

    A comparison was made of ethanol's effects on the order of plasma membranes in intact cells and some isolated membrane preparations. Order was assessed by steady-state fluorescence polarization techniques using the non-permeant probe, TMA-DPH. The data show that two cultured cells, rat neonatal astroglial and N2A neuroblastoma, were sensitive to significant ethanol-induced disordering within the anesthetically relevant range. Human erythrocytes, cultured fibroblasts and homogenized astroglial cells required higher ethanol concentrations to produce a similar effect. Intact erythrocytes were approximately twice as sensitive as erythrocyte ghost membranes to ethanol induced perturbation. The neonatal glial and N2A cells were approximately five times more sensitive than synaptic membranes to ethanol effects. DMPC and DMPC + cholesterol liposomes and myelin membranes were insensitive to ethanol's effects. The incorporation of 10 mole % ganglioside GM{sub 1} sensitized the liposomes to ethanol-induced perturbation.

  18. Intact capture of hypervelocity particles

    NASA Technical Reports Server (NTRS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    1986-01-01

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  19. Intact capture of hypervelocity particles

    NASA Astrophysics Data System (ADS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  20. Oncogenes induce the cancer-associated fibroblast phenotype: metabolic symbiosis and "fibroblast addiction" are new therapeutic targets for drug discovery.

    PubMed

    Lisanti, Michael P; Martinez-Outschoorn, Ubaldo E; Sotgia, Federica

    2013-09-01

    Metabolic coupling, between mitochondria in cancer cells and catabolism in stromal fibroblasts, promotes tumor growth, recurrence, metastasis, and predicts anticancer drug resistance. Catabolic fibroblasts donate the necessary fuels (such as L-lactate, ketones, glutamine, other amino acids, and fatty acids) to anabolic cancer cells, to metabolize via their TCA cycle and oxidative phosphorylation (OXPHOS). This provides a simple mechanism by which metabolic energy and biomass are transferred from the host microenvironment to cancer cells. Recently, we showed that catabolic metabolism and "glycolytic reprogramming" in the tumor microenvironment are orchestrated by oncogene activation and inflammation, which originates in epithelial cancer cells. Oncogenes drive the onset of the cancer-associated fibroblast phenotype in adjacent normal fibroblasts via paracrine oxidative stress. This oncogene-induced transition to malignancy is "mirrored" by a loss of caveolin-1 (Cav-1) and an increase in MCT4 in adjacent stromal fibroblasts, functionally reflecting catabolic metabolism in the tumor microenvironment. Virtually identical findings were obtained using BRCA1-deficient breast and ovarian cancer cells. Thus, oncogene activation (RAS, NFkB, TGF-β) and/or tumor suppressor loss (BRCA1) have similar functional effects on adjacent stromal fibroblasts, initiating "metabolic symbiosis" and the cancer-associated fibroblast phenotype. New therapeutic strategies that metabolically uncouple oxidative cancer cells from their glycolytic stroma or modulate oxidative stress could be used to target this lethal subtype of cancers. Targeting "fibroblast addiction" in primary and metastatic tumor cells may expose a critical Achilles' heel, leading to disease regression in both sporadic and familial cancers.

  1. Pancreatic cancer-secreted miR-155 implicates in the conversion from normal fibroblasts to cancer-associated fibroblasts

    PubMed Central

    Pang, Wenjing; Su, Jiaojiao; Wang, Yalei; Feng, Hui; Dai, Xin; Yuan, Yaozong; Chen, Xi; Yao, Weiyan

    2015-01-01

    Cancer-associated fibroblasts (CAF) are a major constituent of the pancreatic cancer microenvironment and that the meaning is as intended. Pancreatic cancer cells can induce normal fibroblasts to convert into CAF and, reciprocally, CAF promote tumor invasions and proliferations. The mechanism of the conversion from normal fibroblasts (NF) to CAF remains unclear. MicroRNA are short non-coding RNA involved in the post-transcription gene regulation, which have been defined as an imperative controller in tumor invasions, proliferations and colony formations. Microvesicles (MV) have been proved to be an important mediator of intercellular communication and can selectively transport secreted microRNA from a donor cell into a recipient cell. In this study, we isolated primary pancreatic fibroblasts from wild type C57 mice and co-cultured them with pancreatic cancer cell lines, BxPC-3 and SW1990, and observed the conversion from NF to CAF, or at least CAF-like cells. This phenomenon could also be replicated in primary fibroblasts treated with MV separated from a cancer cell media. We identified that miR-155 was upregulated in PaC-derived MV and we confirmed that normal fibroblasts could convert into CAF after MV containing miR-155 had been taken up. TP53INP1 is a target of miR-155 in fibroblasts and a downregulation of TP53INP1 protein levels could contribute to the fibroblasts’ activation. These results indicated that pancreatic cancer cells might reprogram normal adjacent fibroblasts into CAF by means of secreted MV containing miR-155. Targeting the circulating microRNA might be a potential therapy for malignant tumors. PMID:26195069

  2. Interleukin 6 in intact and injured mouse peripheral nerves.

    PubMed

    Reichert, F; Levitzky, R; Rotshenker, S

    1996-03-01

    The multifunctional cytokine interleukin 6 (IL-6) has direct growth, survival and differentiation effects on peripheral and central neurons. Furthermore, it can modulate the production by non-neuronal cells of other cytokines and growth factors, and thereby affect nerve cells indirectly. We have studied IL-6 expression and production in intact and injured peripheral nerves of C57/BL/6NHSD mice, which display the normal rapid progression of Wallerian degeneration. The IL-6 mRNA was detected in nerves degenerating in vitro or in vivo, but not in intact nerves. In vitro- and in vivo-degenerating nerve segments and neuroma nerve segments synthesized and secreted IL-6. The onset of IL-6 production was rapid and prolonged. It was detected as early as 2 h after injury and persisted for the entire period of 21 days tested after the injury. Of the non-neuronal cells that reside in intact and injured nerves, macrophages and fibroblasts were the major contributors to IL-6 production. We also studied IL-6 production in intact and injured nerves of mutant C57BL/6-WLD/OLA/NHSD mice, which display very slow progression of Wallerian degeneration. Injured nerves of C57BL/6-WLD/OLA/NHSD mice produced significantly lower amounts of IL-6 than did rapidly degenerating nerves of C57/BL/6NHSD mice.

  3. Intact capture of cosmic dust

    NASA Technical Reports Server (NTRS)

    Tsou, P.

    1991-01-01

    The focus of this development effort is to capture dust particles at hypervelocities intact and unmelted in order to preserve volatile organics. At the same time, the capture process must minimize any organic elemental or compound contamination to prevent any compromise of exobiological analyses. Inorganic silicate aerogel has been developed as a successful capture medium to satisfy both requirements of intact capture and minimal organic contamination. Up to 6 km/s, silicate projectiles from a few microns up to 100 microns have been captured intact without any melting and with minimal loss of mass. Carbon in silicate aerogel can be reduced to less than 1 part in 1000 and hydrogen 3 parts in 1000 when baked in air. Under controlled inert gas environments, additional hydrocarbon reduction can be achieved.

  4. Upregulation of Mitochondrial Content in Cytochrome c Oxidase Deficient Fibroblasts.

    PubMed

    Kogot-Levin, Aviram; Saada, Ann; Leibowitz, Gil; Soiferman, Devorah; Douiev, Liza; Raz, Itamar; Weksler-Zangen, Sarah

    2016-01-01

    Cytochrome-c-oxidase (COX) deficiency is a frequent cause of mitochondrial disease and is associated with a wide spectrum of clinical phenotypes. We studied mitochondrial function and biogenesis in fibroblasts derived from the Cohen (CDs) rat, an animal model of COX deficiency. COX activity in CDs-fibroblasts was 50% reduced compared to control rat fibroblasts (P<0.01). ROS-production in CDs fibroblasts increased, along with marked mitochondrial fragmentation and decreased mitochondrial membrane-potential, indicating mitochondrial dysfunction. Surprisingly, cellular ATP content, oxygen consumption rate (OCR) and the extracellular acidification rate (ECAR) were unchanged. To clarify the discrepancy between mitochondrial dysfunction and ATP production, we studied mitochondrial biogenesis and turnover. The content of mitochondria was higher in CDs-fibroblasts. Consistently, AMPK activity and the expression of NRF1-target genes, NRF2 and PGC1-α that mediate mitochondrial biogenesis were increased (P<0.01 vs control fibroblast). In CDs-fibrobalsts, the number of autophagosomes (LC3+ puncta) containing mitochondria in CDs fibroblasts was similar to that in control fibroblasts, suggesting that mitophagy was intact. Altogether, our findings demonstrate that mitochondrial dysfunction and oxidative stress are associated with an increase in mitochondrial biogenesis, resulting in preservation of ATP generation.

  5. Reprogramming of somatic cells induced by fusion of embryonic stem cells using hemagglutinating virus of Japan envelope (HVJ-E)

    SciTech Connect

    Yue, Xiao-shan; Fujishiro, Masako; Toyoda, Masashi; Akaike, Toshihiro; Ito, Yoshihiro

    2010-04-16

    In this research, hemagglutinating virus of Japan envelope (HVJ-E) was used to reprogram somatic cells by fusion with mouse embryonic stem (ES) cells. Neomycin-resistant mouse embryonic fibroblasts (MEFs) were used as somatic cells. Nanog-overexpressing puromycin-resistant EB3 cells were used as mouse ES cells. These two cells were fused by exposing to HVJ-E and the generated fusion cells were selected by puromycin and G418 to get the stable fusion cell line. The fusion cells form colonies in feeder-free culture system. Microsatellite analysis of the fusion cells showed that they possessed genes from both ES cells and fibroblasts. The fusion cells were tetraploid, had alkali phosphatase activity, and expressed stem cell marker genes such as Pou5f1, Nanog, and Sox2, but not the fibroblast cell marker genes such as Col1a1 and Col1a2. The pluripotency of fusion cells was confirmed by their expression of marker genes for all the three germ layers after differentiation induction, and by their ability to form teratoma which contained all the three primary layers. Our results show that HVJ-E can be used as a fusion reagent for reprogramming of somatic cells.

  6. Establishing epigenetic variation during genome reprogramming

    PubMed Central

    2013-01-01

    Transgenerational reprogramming of DNA methylation is important for transposon silencing and epigenetic inheritance. A stochastic regulation of methylation states in the germline may lead to epigenetic variation and the formation of epialleles that contribute to phenotypic variation. In Arabidopsis thaliana inbred lines, the frequency of single base variation of DNA methylation is much higher than genetic mutation and, interestingly, variable epialleles are pre-methylated in the male germline. However, these same alleles are targeted for demethylation in the pollen vegetative nucleus, by a mechanism that seems to contribute to the accumulation of small RNAs that reinforce transcriptional gene silencing in the gametes. These observations are paving the way toward understanding the extent of epigenetic reprogramming in higher plants, and the mechanisms regulating the stability of acquired epigenetic states across generations. PMID:23774895

  7. Reprogramming of germ cells into pluripotency

    PubMed Central

    Sekita, Yoichi; Nakamura, Toshinobu; Kimura, Tohru

    2016-01-01

    Primordial germ cells (PGCs) are precursors of all gametes, and represent the founder cells of the germline. Although developmental potency is restricted to germ-lineage cells, PGCs can be reprogrammed into a pluripotent state. Specifically, PGCs give rise to germ cell tumors, such as testicular teratomas, in vivo, and to pluripotent stem cells known as embryonic germ cells in vitro. In this review, we highlight the current knowledge on signaling pathways, transcriptional controls, and post-transcriptional controls that govern germ cell differentiation and de-differentiation. These regulatory processes are common in the reprogramming of germ cells and somatic cells, and play a role in the pathogenesis of human germ cell tumors. PMID:27621759

  8. Epigenetic switch drives the conversion of fibroblasts into proinvasive cancer-associated fibroblasts

    PubMed Central

    Albrengues, Jean; Bertero, Thomas; Grasset, Eloise; Bonan, Stephanie; Maiel, Majdi; Bourget, Isabelle; Philippe, Claude; Herraiz Serrano, Cecilia; Benamar, Samia; Croce, Olivier; Sanz-Moreno, Victoria; Meneguzzi, Guerrino; Feral, Chloe C.; Cristofari, Gael; Gaggioli, Cedric

    2015-01-01

    Carcinoma-associated fibroblasts (CAF) mediate the onset of a proinvasive tumour microenvironment. The proinflammatory cytokine LIF reprograms fibroblasts into a proinvasive phenotype, which promotes extracellular matrix remodelling and collective invasion of cancer cells. Here we unveil that exposure to LIF initiates an epigenetic switch leading to the constitutive activation of JAK1/STAT3 signalling, which results in sustained proinvasive activity of CAF. Mechanistically, p300-histone acetyltransferase acetylates STAT3, which, in turn, upregulates and activates the DNMT3b DNA methyltransferase. DNMT3b methylates CpG sites of the SHP-1 phosphatase promoter, which abrogates SHP-1 expression, and results in constitutive phosphorylation of JAK1. Sustained JAK1/STAT3 signalling is maintained by DNA methyltransferase DNMT1. Consistently, in human lung and head and neck carcinomas, STAT3 acetylation and phosphorylation are inversely correlated with SHP-1 expression. Combined inhibition of DNMT activities and JAK signalling, in vitro and in vivo, results in long-term reversion of CAF-associated proinvasive activity and restoration of the wild-type fibroblast phenotype. PMID:26667266

  9. Progress in the reprogramming of somatic cells.

    PubMed

    Ma, Tianhua; Xie, Min; Laurent, Timothy; Ding, Sheng

    2013-02-01

    Pluripotent stem cells can differentiate into nearly all types of cells in the body. This unique potential provides significant promise for cell-based therapies to restore tissues or organs destroyed by injuries, degenerative diseases, aging, or cancer. The discovery of induced pluripotent stem cell (iPSC) technology offers a possible strategy to generate patient-specific pluripotent stem cells. However, because of concerns about the specificity, efficiency, kinetics, and safety of iPSC reprogramming, improvements or fundamental changes in this process are required before their effective clinical use. A chemical approach is regarded as a promising strategy to improve and change the iPSC process. Dozens of small molecules have been identified that can functionally replace reprogramming factors and significantly improve iPSC reprogramming. In addition to the prospect of deriving patient-specific tissues and organs from iPSCs, another attractive strategy for regenerative medicine is transdifferentiation-the direct conversion of one somatic cell type to another. Recent studies revealed a new paradigm of transdifferentiation: using transcription factors used in iPSC generation to induce transdifferentiation or called iPSC transcription factor-based transdifferentiation. This type of transdifferentiation not only reveals and uses the developmentally plastic intermediates generated during iPSC reprogramming but also produces a wide range of cells, including expandable tissue-specific precursor cells. Here, we review recent progress of small molecule approaches in the generation of iPSCs. In addition, we summarize the new concept of iPSC transcription factor-based transdifferentiation and discuss its application in generating various lineage-specific cells, especially cardiovascular cells.

  10. Proteome adaptation in cell reprogramming proceeds via distinct transcriptional networks.

    PubMed

    Benevento, Marco; Tonge, Peter D; Puri, Mira C; Hussein, Samer M I; Cloonan, Nicole; Wood, David L; Grimmond, Sean M; Nagy, Andras; Munoz, Javier; Heck, Albert J R

    2014-12-10

    The ectopic expression of Oct4, Klf4, c-Myc and Sox2 (OKMS) transcription factors allows reprogramming of somatic cells into induced pluripotent stem cells (iPSCs). The reprogramming process, which involves a complex network of molecular events, is not yet fully characterized. Here we perform a quantitative mass spectrometry-based analysis to probe in-depth dynamic proteome changes during somatic cell reprogramming. Our data reveal defined waves of proteome resetting, with the first wave occurring 48 h after the activation of the reprogramming transgenes and involving specific biological processes linked to the c-Myc transcriptional network. A second wave of proteome reorganization occurs in a later stage of reprogramming, where we characterize the proteome of two distinct pluripotent cellular populations. In addition, the overlay of our proteome resource with parallel generated -omics data is explored to identify post-transcriptionally regulated proteins involved in key steps during reprogramming.

  11. Matrix identity and tractional forces influence indirect cardiac reprogramming

    PubMed Central

    Kong, Yen P.; Carrion, Bita; Singh, Rahul K.; Putnam, Andrew J.

    2013-01-01

    Heart regeneration through in vivo cardiac reprogramming has been demonstrated as a possible regenerative strategy. While it has been reported that cardiac reprogramming in vivo is more efficient than in vitro, the influence of the extracellular microenvironment on cardiac reprogramming remains incompletely understood. This understanding is necessary to improve the efficiency of cardiac reprogramming in order to implement this strategy successfully. Here we have identified matrix identity and cell-generated tractional forces as key determinants of the dedifferentiation and differentiation stages during reprogramming. Cell proliferation, matrix mechanics, and matrix microstructure are also important, but play lesser roles. Our results suggest that the extracellular microenvironment can be optimized to enhance cardiac reprogramming. PMID:24326998

  12. Direct reprogramming and biomaterials for controlling cell fate.

    PubMed

    Kim, Eunsol; Tae, Giyoong

    2016-01-01

    Direct reprogramming which changes the fate of matured cell is a very useful technique with a great interest recently. This approach can eliminate the drawbacks of direct usage of stem cells and allow the patient specific treatment in regenerative medicine. Overexpression of diverse factors such as general reprogramming factors or lineage specific transcription factors can change the fate of already differentiated cells. On the other hand, biomaterials can provide physical and topographical cues or biochemical cues on cells, which can dictate or significantly affect the differentiation of stem cells. The role of biomaterials on direct reprogramming has not been elucidated much, but will be potentially significant to improve the efficiency or specificity of direct reprogramming. In this review, the strategies for general direct reprogramming and biomaterials-guided stem cell differentiation are summarized with the addition of the up-to-date progress on biomaterials for direct reprogramming.

  13. Epigenetic Control of Reprogramming and Transdifferentiation by Histone Modifications.

    PubMed

    Qin, Hua; Zhao, Andong; Zhang, Cuiping; Fu, Xiaobing

    2016-12-01

    Somatic cells can be reprogrammed to pluripotent stem cells or transdifferentiate to another lineage cell type. Much efforts have been made to unravel the epigenetic mechanisms underlying the cell fate conversion. Histone modifications as the major epigenetic regulator are implicated in various aspects of reprogramming and transdifferentiation. Here, we discuss the roles of histone modifications on reprogramming and transdifferentiation and hopefully provide new insights into induction and promotion of the cell fate conversion by modulating histone modifications.

  14. Reprogramming stem cells is a microenvironmental task

    SciTech Connect

    Bissell, Mina J; Inman, Jamie

    2008-10-14

    That tumor cells for all practical purposes are unstable and plastic could be expected. However, the astonishing ability of the nuclei from cells of normal adult tissues to be reprogrammed - given the right embryonic context - found its final truth even for mammals in the experiments that allowed engineering Dolly (1). The landmark experiments showed that nuclei originating from cells of frozen mammary tissues were capable of being reprogrammed by the embryonic cytoplasm and its microenvironment to produce a normal sheep. The rest is history. However, whether microenvironments other than those of the embryos can also reprogram adult cells of different tissue origins still containing their cytoplasm is of obvious interest. In this issue of PNAS, the laboratory of Gilbert Smith (2) reports on how the mammary gland microenvironment can reprogram both embryonic and adult stem neuronal cells. The work is a follow-up to their previous report on testis stem cells that were reprogrammed by the mammary microenvironment (3). They demonstrated that cells isolated from the seminiferous tubules of the mature testis, mixed with normal mammary epithelial cells, contributed a sizable number of epithelial progeny to normal mammary outgrowths in transplanted mammary fat pads. However, in those experiments they were unable to distinguish which subpopulation of the testis cells contributed progeny to the mammary epithelial tree. The current work adds new, compelling, and provocative information to our understanding of stem cell plasticity. Booth et al. (2) use neuronal stem cells (NSCs) isolated from WAP-cre/R26R mice combined with unlabeled mammary epithelial cells that subsequently are implanted in cleared mammary fat pads. In this new microenvironment, the NSCs that are incorporated into the branching mammary tree make chimeric glands (Fig. 1) that remarkably can also express the milk protein {beta}-casein, progesterone receptor, and estrogen receptor {alpha}. Remarkably, the

  15. Acquisition of pluripotency through continued environmental influence on OCT4-induced plastic human fibroblasts.

    PubMed

    Salci, Kyle R; Lee, Jung Bok; Mitchell, Ryan R; Orlando, Luca; Fiebig-Comyn, Aline; Shapovalova, Zoya; Bhatia, Mickie

    2015-07-01

    The combination of OCT4 expression and short-term exposure to reprogramming media induces a state of transcriptional plasticity in human fibroblasts, capable of responding to changes in the extracellular environment that facilitate direct cell fate conversion toward lineage specific progenitors. Here we reveal that continued exposure of OCT4-induced plastic human fibroblasts to reprogramming media (RM) is sufficient to induce pluripotency. OCT4-derived induced pluripotent stem cell (iPSC(OCT4)) colonies emerged after prolonged culture in RM, and formed independently of lineage specific progenitors. Human iPSC(OCT4) are morphologically indistinguishable from conventionally derived iPSCs and express core proteins involved in maintenance of pluripotency. iPSC(OCT4) display in vivo functional pluripotency as measured by teratoma formation consisting of the three germ layers, and are capable of targeted in vitro differentiation. Our study indicates that acquisition of pluripotency is one of multiple cell fate choices that can be facilitated through environmental stimulation of OCT4-induced plasticity, and suggests the role of other reprogramming factors to induce pluripotency can be substituted by prolonged culture of plastic fibroblasts.

  16. Analysis of human and mouse reprogramming of somatic cells to induced pluripotent stem cells. What is in the plate?

    PubMed

    Boué, Stéphanie; Paramonov, Ida; Barrero, María José; Izpisúa Belmonte, Juan Carlos

    2010-09-17

    After the hope and controversy brought by embryonic stem cells two decades ago for regenerative medicine, a new turn has been taken in pluripotent cells research when, in 2006, Yamanaka's group reported the reprogramming of fibroblasts to pluripotent cells with the transfection of only four transcription factors. Since then many researchers have managed to reprogram somatic cells from diverse origins into pluripotent cells, though the cellular and genetic consequences of reprogramming remain largely unknown. Furthermore, it is still unclear whether induced pluripotent stem cells (iPSCs) are truly functionally equivalent to embryonic stem cells (ESCs) and if they demonstrate the same differentiation potential as ESCs. There are a large number of reprogramming experiments published so far encompassing genome-wide transcriptional profiling of the cells of origin, the iPSCs and ESCs, which are used as standards of pluripotent cells and allow us to provide here an in-depth analysis of transcriptional profiles of human and mouse cells before and after reprogramming. When compared to ESCs, iPSCs, as expected, share a common pluripotency/self-renewal network. Perhaps more importantly, they also show differences in the expression of some genes. We concentrated our efforts on the study of bivalent domain-containing genes (in ESCs) which are not expressed in ESCs, as they are supposedly important for differentiation and should possess a poised status in pluripotent cells, i.e. be ready to but not yet be expressed. We studied each iPSC line separately to estimate the quality of the reprogramming and saw a correlation of the lowest number of such genes expressed in each respective iPSC line with the stringency of the pluripotency test achieved by the line. We propose that the study of expression of bivalent domain-containing genes, which are normally silenced in ESCs, gives a valuable indication of the quality of the iPSC line, and could be used to select the best iPSC lines

  17. Identification of the early and late responder genes during the generation of induced pluripotent stem cells from mouse fibroblasts

    PubMed Central

    Ham, Seokjin; Hong, Chang-Pyo; Seo, Seonghye; Choe, Moon Kyung; Shin, So-I; Lee, Choon-Soo; Kim, Hyo-Soo

    2017-01-01

    Background The generation of induced pluripotent stem cell (iPSC), a substitute for embryonic stem cell (ESC), requires the proper orchestration of a transcription program at the chromatin level. Our recent approach for the induction of pluripotent stem cells from fibroblasts using protein extracts from mouse ESCs could overcome the potential tumorigenicity risks associated with random retroviral integration. Here, we examine the epigenetic modifications and the transcriptome of two types of iPSC and of partially reprogrammed iPSCs (iPSCp) generated independently from adult cardiac and skin fibroblasts to assess any perturbations of the transcription program during reprogramming. Results The comparative dissection of the transcription profiles and histone modification patterns at lysines 4 and 27 of histone H3 of the iPSC, iPSCp, ESC, and somatic cells revealed that the iPSC was almost completely comparable to the ESC, regardless of their origins, whereas the genes of the iPSCp were dysregulated to a larger extent. Regardless of the origins of the somatic cells, the fibroblasts induced using the ESC protein extracts appear to be completely reprogrammed into pluripotent cells, although they show unshared marginal differences in their gene expression programs, which may not affect the maintenance of stemness. A comparative investigation of the iPSCp generated by unwanted reprogramming showed that the two groups of genes on the pathway from somatic cells to iPSC might function as sequential reprogramming-competent early and late responders to the induction stimulus. Moreover, some of the divergent genes expressed only in the iPSCp were associated with many tumor-related pathways. Conclusions Faithful transcriptional reprogramming should follow epigenetic alterations to generate induced pluripotent stem cells from somatic cells. This genome-wide comparison enabled us to define the early and late responder genes during the cell reprogramming process to iPSC. Our results

  18. Monitoring Intact Viruses Using Aptamers.

    PubMed

    Kumar, Penmetcha K R

    2016-08-04

    Viral diagnosis and surveillance are necessary steps in containing the spread of viral diseases, and they help in the deployment of appropriate therapeutic interventions. In the past, the commonly employed viral detection methods were either cell-culture or molecule-level assays. Most of these assays are laborious and expensive, require special facilities, and provide a slow diagnosis. To circumvent these limitations, biosensor-based approaches are becoming attractive, especially after the successful commercialization of glucose and other biosensors. In the present article, I have reviewed the current progress using the biosensor approach for detecting intact viruses. At the time of writing this review, three types of bioreceptor surfaces (antibody-, glycan-, and aptamer-based) have been explored on different sensing platforms for detecting intact viruses. Among these bioreceptors, aptamer-based sensors have been increasingly explored for detecting intact viruses using surface plasmon resonance (SPR) and other platforms. Special emphasis is placed on the aptamer-based SPR platform in the present review.

  19. Monitoring Intact Viruses Using Aptamers

    PubMed Central

    Kumar, Penmetcha K. R.

    2016-01-01

    Viral diagnosis and surveillance are necessary steps in containing the spread of viral diseases, and they help in the deployment of appropriate therapeutic interventions. In the past, the commonly employed viral detection methods were either cell-culture or molecule-level assays. Most of these assays are laborious and expensive, require special facilities, and provide a slow diagnosis. To circumvent these limitations, biosensor-based approaches are becoming attractive, especially after the successful commercialization of glucose and other biosensors. In the present article, I have reviewed the current progress using the biosensor approach for detecting intact viruses. At the time of writing this review, three types of bioreceptor surfaces (antibody-, glycan-, and aptamer-based) have been explored on different sensing platforms for detecting intact viruses. Among these bioreceptors, aptamer-based sensors have been increasingly explored for detecting intact viruses using surface plasmon resonance (SPR) and other platforms. Special emphasis is placed on the aptamer-based SPR platform in the present review. PMID:27527230

  20. Alleviating GAA Repeat Induced Transcriptional Silencing of the Friedreich's Ataxia Gene During Somatic Cell Reprogramming.

    PubMed

    Polak, Urszula; Li, Yanjie; Butler, Jill Sergesketter; Napierala, Marek

    2016-12-01

    Friedreich's ataxia (FRDA) is the most common autosomal recessive ataxia. This severe neurodegenerative disease is caused by an expansion of guanine-adenine-adenine (GAA) repeats located in the first intron of the frataxin (FXN) gene, which represses its transcription. Although transcriptional silencing is associated with heterochromatin-like changes in the vicinity of the expanded GAAs, the exact mechanism and pathways involved in transcriptional inhibition are largely unknown. As major remodeling of the epigenome is associated with somatic cell reprogramming, modulating chromatin modification pathways during the cellular transition from a somatic to a pluripotent state is likely to generate permanent changes to the epigenetic landscape. We hypothesize that the epigenetic modifications in the vicinity of the GAA repeats can be reversed by pharmacological modulation during somatic cell reprogramming. We reprogrammed FRDA fibroblasts into induced pluripotent stem cells (iPSCs) in the presence of various small molecules that target DNA methylation and histone acetylation and methylation. Treatment of FRDA iPSCs with two compounds, sodium butyrate (NaB) and Parnate, led to an increase in FXN expression and correction of repressive marks at the FXN locus, which persisted for several passages. However, prolonged culture of the epigenetically modified FRDA iPSCs led to progressive expansions of the GAA repeats and a corresponding decrease in FXN expression. Furthermore, we uncovered that differentiation of these iPSCs into neurons also results in resilencing of the FXN gene. Taken together, these results demonstrate that transcriptional repression caused by long GAA repeat tracts can be partially or transiently reversed by altering particular epigenetic modifications, thus revealing possibilities for detailed analyses of silencing mechanism and development of new therapeutic approaches for FRDA.

  1. Reprogramming cells to study vacuolar development

    PubMed Central

    Feeney, Mistianne; Frigerio, Lorenzo; Kohalmi, Susanne E.; Cui, Yuhai; Menassa, Rima

    2013-01-01

    During vegetative and embryonic developmental transitions, plant cells are massively reorganized to support the activities that will take place during the subsequent developmental phase. Studying cellular and subcellular changes that occur during these short transitional periods can sometimes present challenges, especially when dealing with Arabidopsis thaliana embryo and seed tissues. As a complementary approach, cellular reprogramming can be used as a tool to study these cellular changes in another, more easily accessible, tissue type. To reprogram cells, genetic manipulation of particular regulatory factors that play critical roles in establishing or repressing the seed developmental program can be used to bring about a change of cell fate. During different developmental phases, vacuoles assume different functions and morphologies to respond to the changing needs of the cell. Lytic vacuoles (LVs) and protein storage vacuoles (PSVs) are the two main vacuole types found in flowering plants such as Arabidopsis. Although both are morphologically distinct and carry out unique functions, they also share some similar activities. As the co-existence of the two vacuole types is short-lived in plant cells, how they replace each other has been a long-standing curiosity. To study the LV to PSV transition, LEAFY COTYLEDON2, a key transcriptional regulator of seed development, was overexpressed in vegetative cells to activate the seed developmental program. At the cellular level, Arabidopsis leaf LVs were observed to convert to PSV-like organelles. This presents the opportunity for further research to elucidate the mechanism of LV to PSV transitions. Overall, this example demonstrates the potential usefulness of cellular reprogramming as a method to study cellular processes that occur during developmental transitions. PMID:24348496

  2. Metabolic Reprogramming of Stem Cell Epigenetics

    PubMed Central

    Ryall, James G.; Cliff, Tim; Dalton, Stephen; Sartorelli, Vittorio

    2015-01-01

    Summary For many years, stem cell metabolism was viewed as a by product of cell fate status rather than an active regulatory mechanism, however there is now a growing appreciation that metabolic pathways influence epigenetic changes associated with lineage commitment, specification, and self-renewal. Here we review how metabolites generated during glycolytic and oxidative processes are utilized in enzymatic reactions leading to epigenetic modifications and transcriptional regulation. We discuss how “metabolic reprogramming” contributes to global epigenetic changes in the context of naïve and primed pluripotent states, somatic reprogramming, and hematopoietic and skeletal muscle tissue stem cells, and the implications for regenerative medicine. PMID:26637942

  3. Sir John Gurdon: Father of nuclear reprogramming

    PubMed Central

    Blau, Helen M.

    2015-01-01

    Sir John Gurdon founded the field of nuclear reprogramming. His work set the stage for the ever burgeoning area of stem cell biology and regenerative medicine. Here I provide personal reflections on times I shared with John Gurdon and professional reflections of the impact of his ground-breaking research on my own development as a scientist and on the field in general. His paradigm-shifting experiments will continue to provoke scientists to think outside the box for many years to come. PMID:24954777

  4. Authentication in Reprogramming of Sensor Networks for Mote Class Adversaries

    DTIC Science & Technology

    2006-01-01

    Authentication in Reprogramming of Sensor Networks for Mote Class Adversaries 1 Limin Wang Sandeep S. Kulkarni Software Engineering and Network...Systems Laboratory Department of Computer Science and Engineering Michigan State University East Lansing MI 48824 USA Abstract Reprogramming is an... Engineering ,Software Engineering and Network Systems Laboratory,East Lansing,MI,48824 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING

  5. Aberrant DNA methylation reprogramming in bovine SCNT preimplantation embryos

    PubMed Central

    Zhang, Sheng; Chen, Xin; Wang, Fang; An, Xinglan; Tang, Bo; Zhang, Xueming; Sun, Liguang; Li, Ziyi

    2016-01-01

    DNA methylation reprogramming plays important roles in mammalian embryogenesis. Mammalian somatic cell nuclear transfer (SCNT) embryos with reprogramming defects fail to develop. Thus, we compared DNA methylation reprogramming in preimplantation embryos from bovine SCNT and in vitro fertilization (IVF) and analyzed the influence of vitamin C (VC) on the reprogramming of DNA methylation. The results showed that global DNA methylation followed a typical pattern of demethylation and remethylation in IVF preimplantation embryos; however, the global genome remained hypermethylated in SCNT preimplantation embryos. Compared with the IVF group, locus DNA methylation reprogramming showed three patterns in the SCNT group. First, some pluripotency genes (POU5F1 and NANOG) and repeated elements (satellite I and α-satellite) showed insufficient demethylation and hypermethylation in the SCNT group. Second, a differentially methylated region (DMR) of an imprint control region (ICR) in H19 exhibited excessive demethylation and hypomethylation. Third, some pluripotency genes (CDX2 and SOX2) were hypomethylated in both the IVF and SCNT groups. Additionally, VC improved the DNA methylation reprogramming of satellite I, α-satellite and H19 but not that of POU5F1 and NANOG in SCNT preimplantation embryos. These results indicate that DNA methylation reprogramming was aberrant and that VC influenced DNA methylation reprogramming in SCNT embryos in a locus-specific manner. PMID:27456302

  6. Dnmt3l-knockout donor cells improve somatic cell nuclear transfer reprogramming efficiency.

    PubMed

    Liao, Hung-Fu; Mo, Chu-Fan; Wu, Shinn-Chih; Cheng, Dai-Han; Yu, Chih-Yun; Chang, Kai-Wei; Kao, Tzu-Hao; Lu, Chia-Wei; Pinskaya, Marina; Morillon, Antonin; Lin, Shih-Shun; Cheng, Winston T K; Bourc'his, Déborah; Bestor, Timothy; Sung, Li-Ying; Lin, Shau-Ping

    2015-10-01

    Nuclear transfer (NT) is a technique used to investigate the development and reprogramming potential of a single cell. DNA methyltransferase-3-like, which has been characterized as a repressive transcriptional regulator, is expressed in naturally fertilized egg and morula/blastocyst at pre-implantation stages. In this study, we demonstrate that the use of Dnmt3l-knockout (Dnmt3l-KO) donor cells in combination with Trichostatin A treatment improved the developmental efficiency and quality of the cloned embryos. Compared with the WT group, Dnmt3l-KO donor cell-derived cloned embryos exhibited increased cell numbers as well as restricted OCT4 expression in the inner cell mass (ICM) and silencing of transposable elements at the blastocyst stage. In addition, our results indicate that zygotic Dnmt3l is dispensable for cloned embryo development at pre-implantation stages. In Dnmt3l-KO mouse embryonic fibroblasts, we observed reduced nuclear localization of HDAC1, increased levels of the active histone mark H3K27ac and decreased accumulation of the repressive histone marks H3K27me3 and H3K9me3, suggesting that Dnmt3l-KO donor cells may offer a more permissive epigenetic state that is beneficial for NT reprogramming.

  7. Role of Hepatic-Specific Transcription Factors and Polycomb Repressive Complex 2 during Induction of Fibroblasts to Hepatic Fate

    PubMed Central

    Wee, Ping; Yaqubi, Moein

    2016-01-01

    Direct reprogramming using defined sets of transcription factors (TFs) is a recent strategy for generating induced hepatocytes (iHeps) from fibroblasts for use in regenerative medicine and drug development. Comprehensive studies detailing the regulatory role of TFs during this reprogramming process could help increase its efficiency. This study aimed to find the TFs with the greatest influences on the generation of iHeps from fibroblasts, and to further understand their roles in the regulation of the gene expression program. Here, we used systems biology approaches to analyze high quality expression data sets in combination with TF-binding sites data and protein-protein interactions data during the direct reprogramming of fibroblasts to iHeps. Our results revealed two main patterns for differentially expressed genes (DEGs): up-regulated genes were categorized as hepatic-specific pattern, and down-regulated genes were categorized as mesoderm- and fibroblast-specific pattern. Interestingly, hepatic-specific genes co-expressed and were regulated by hepatic-specific TFs, specifically Hnf4a and Foxa2. Conversely, the mesoderm- and fibroblast-specific pattern was mainly silenced by polycomb repressive complex 2 (PRC2) members, including Suz12, Mtf2, Ezh2, and Jarid2. Independent analysis of both the gene and core regulatory network of DE-TFs showed significant roles for Hnf4a, Foxa2, and PRC2 members in the regulation of the gene expression program and in biological processes during the direct conversion process. Altogether, using systems biology approaches, we clarified the role of Hnf4a and Foxa2 as hepatic-specific TFs, and for the first time, introduced the PRC2 complex as the main regulator that favors the direct reprogramming process in cooperation with hepatic-specific factors. PMID:27902735

  8. Transcription factor-mediated reprogramming: epigenetics and therapeutic potential.

    PubMed

    Firas, Jaber; Liu, Xiaodong; Lim, Sue Mei; Polo, Jose M

    2015-03-01

    Cellular reprogramming refers to the conversion of one cell type into another by altering its epigenetic marks. This can be achieved by three different methods: somatic cell nuclear transfer, cell fusion and transcription factor (TF)-mediated reprogramming. TF-mediated reprogramming can occur through several means, either reverting backwards to a pluripotent state before redifferentiating to a new cell type (otherwise known as induced pluripotency), by transdifferentiating directly into a new cell type (bypassing the intermediate pluripotent stage), or, by using the induced pluripotency pathway without reaching the pluripotent state. The possibility of reprogramming any cell type of interest not only sheds new insights on cellular plasticity, but also provides a novel use of this technology across several platforms, most notably in cellular replacement therapies, disease modelling and drug screening. This review will focus on the different ways of implementing TF-mediated reprogramming, their associated epigenetic changes and its therapeutic potential.

  9. Direct reprogramming of adult cells: avoiding the pluripotent state.

    PubMed

    Kelaini, Sophia; Cochrane, Amy; Margariti, Andriana

    2014-01-01

    The procedure of using mature, fully differentiated cells and inducing them toward other cell types while bypassing an intermediate pluripotent state is termed direct reprogramming. Avoiding the pluripotent stage during cellular conversions can be achieved either through ectopic expression of lineage-specific factors (transdifferentiation) or a direct reprogramming process that involves partial reprogramming toward the pluripotent stage. Latest advances in the field seek to alleviate concerns that include teratoma formation or retroviral usage when it comes to delivering reprogramming factors to cells. They also seek to improve efficacy and efficiency of cellular conversion, both in vitro and in vivo. The final products of this reprogramming approach could be then directly implemented in regenerative and personalized medicine.

  10. Vectorology and Factor Delivery in Induced Pluripotent Stem Cell Reprogramming

    PubMed Central

    2014-01-01

    Induced pluripotent stem cell (iPSC) reprogramming requires sustained expression of multiple reprogramming factors for a limited period of time (10–30 days). Conventional iPSC reprogramming was achieved using lentiviral or simple retroviral vectors. Retroviral reprogramming has flaws of insertional mutagenesis, uncontrolled silencing, residual expression and re-activation of transgenes, and immunogenicity. To overcome these issues, various technologies were explored, including adenoviral vectors, protein transduction, RNA transfection, minicircle DNA, excisable PiggyBac (PB) transposon, Cre-lox excision system, negative-sense RNA replicon, positive-sense RNA replicon, Epstein-Barr virus-based episomal plasmids, and repeated transfections of plasmids. This review provides summaries of the main vectorologies and factor delivery systems used in current reprogramming protocols. PMID:24625220

  11. Cell-free extract from porcine induced pluripotent stem cells can affect porcine somatic cell nuclear reprogramming.

    PubMed

    No, Jin-Gu; Choi, Mi-Kyung; Kwon, Dae-Jin; Yoo, Jae Gyu; Yang, Byoung-Chul; Park, Jin-Ki; Kim, Dong-Hoon

    2015-01-01

    Pretreatment of somatic cells with undifferentiated cell extracts, such as embryonic stem cells and mammalian oocytes, is an attractive alternative method for reprogramming control. The properties of induced pluripotent stem cells (iPSCs) are similar to those of embryonic stem cells; however, no studies have reported somatic cell nuclear reprogramming using iPSC extracts. Therefore, this study aimed to evaluate the effects of porcine iPSC extracts treatment on porcine ear fibroblasts and early development of porcine cloned embryos produced from porcine ear skin fibroblasts pretreated with the porcine iPSC extracts. The Chariot(TM) reagent system was used to deliver the iPSC extracts into cultured porcine ear skin fibroblasts. The iPSC extracts-treated cells (iPSC-treated cells) were cultured for 3 days and used for analyzing histone modification and somatic cell nuclear transfer. Compared to the results for nontreated cells, the trimethylation status of histone H3 lysine residue 9 (H3K9) in the iPSC-treated cells significantly decreased. The expression of Jmjd2b, the H3K9 trimethylation-specific demethylase gene, significantly increased in the iPSC-treated cells; conversely, the expression of the proapoptotic genes, Bax and p53, significantly decreased. When the iPSC-treated cells were transferred into enucleated porcine oocytes, no differences were observed in blastocyst development and total cell number in blastocysts compared with the results for control cells. However, H3K9 trimethylation of pronuclear-stage-cloned embryos significantly decreased in the iPSC-treated cells. Additionally, Bax and p53 gene expression in the blastocysts was significantly lower in iPSC-treated cells than in control cells. To our knowledge, this study is the first to show that an extracts of porcine iPSCs can affect histone modification and gene expression in porcine ear skin fibroblasts and cloned embryos.

  12. Efficient production of retroviruses using PLGA/bPEI-DNA nanoparticles and application for reprogramming somatic cells.

    PubMed

    Seo, Eun Jin; Jang, Il Ho; Do, Eun Kyoung; Cheon, Hyo Cheon; Heo, Soon Chul; Kwon, Yang Woo; Jeong, Geun Ok; Kim, Ba Reun; Kim, Jae Ho

    2013-01-01

    Reprogramming of somatic cells to pluripotent cells requires the introduction of factors driving fate switches. Viral delivery has been the most efficient method for generation of induced pluripotent stem cells. Transfection, which precedes virus production, is a commonly-used process for delivery of nucleic acids into cells. The aim of this study is to evaluate the efficiency of PLGA/ bPEI nanoparticles in transfection and virus production. Using a modified method of producing PLGA nanoparticles, PLGA/bPEI-DNA nanoparticles were examined for transfection efficiency and virus production yield in comparison with PLGA-DNA, bPEI-DNA nanoparticles or liposome-DNA complexes. After testing various ratios of PLGA, bPEI, and DNA, the ratio of 6:3:1 (PLGA:bPEI:DNA, w/w/w) was determined to be optimal, with acceptable cellular toxicity. PLGA/bPEI-DNA (6:3:1) nanoparticles showed superior transfection efficiency, especially in multiple gene transfection, and viral yield when compared with liposome-DNA complexes. The culture supernatants of HEK293FT cells transfected with PLGA/bPEI-DNA of viral constructs containing reprogramming factors (Oct4, Sox2, Klf4, or c-Myc) successfully and more efficiently generated induced pluripotent stem cell colonies from mouse embryonic fibroblasts. These results strongly suggest that PLGA/bPEI-DNA nanoparticles can provide significant advantages in studying the effect of multiple factor delivery such as in reprogramming or direct conversion of cell fate.

  13. Gene Resistance to Transcriptional Reprogramming following Nuclear Transfer Is Directly Mediated by Multiple Chromatin-Repressive Pathways.

    PubMed

    Jullien, Jerome; Vodnala, Munender; Pasque, Vincent; Oikawa, Mami; Miyamoto, Kei; Allen, George; David, Sarah Anne; Brochard, Vincent; Wang, Stan; Bradshaw, Charles; Koseki, Haruhiko; Sartorelli, Vittorio; Beaujean, Nathalie; Gurdon, John

    2017-03-02

    Understanding the mechanism of resistance of genes to reactivation will help improve the success of nuclear reprogramming. Using mouse embryonic fibroblast nuclei with normal or reduced DNA methylation in combination with chromatin modifiers able to erase H3K9me3, H3K27me3, and H2AK119ub1 from transplanted nuclei, we reveal the basis for resistance of genes to transcriptional reprogramming by oocyte factors. A majority of genes is affected by more than one type of treatment, suggesting that resistance can require repression through multiple epigenetic mechanisms. We classify resistant genes according to their sensitivity to 11 chromatin modifier combinations, revealing the existence of synergistic as well as adverse effects of chromatin modifiers on removal of resistance. We further demonstrate that the chromatin modifier USP21 reduces resistance through its H2AK119 deubiquitylation activity. Finally, we provide evidence that H2A ubiquitylation also contributes to resistance to transcriptional reprogramming in mouse nuclear transfer embryos.

  14. Presence of arylsulfatase A (ARS A) in multiple sulfatase deficiency disorder fibroblasts.

    PubMed

    Fluharty, A L; Stevens, R L; Davis, L L; Shapiro, L J; Kihara, H

    1978-05-01

    Multiple deficiency disorder fibroblasts cultured in MEM-CO2 showed deficiencies of arylsulfatase A(ARS A) comparable to the deficiency in metachromatic leukodystrophy fibroblasts. However, the MSDD fibroblasts cultured in MEM-HEPES contained near normal levels of ARS A. Moreover, the enzyme from the latter fibroblasts was indistinguishable from ARS A of control fibroblasts on DEAE-cellulose chromatography, ratio of activity with several substrates, thermal inactivation, sensitivity to inhibitors, and precipitation by antiserum to human ARS A. These data support the conclusion that the ARS A genome is intact in MSDD fibroblasts and, by extension, in MSDD patients. Other sulfatases were present at levels ranging from mildly deficient to near normal but never as low as seen in the corresponding specific sulfatase deficient disorders.

  15. Nuclear Actin in Development and Transcriptional Reprogramming.

    PubMed

    Misu, Shinji; Takebayashi, Marina; Miyamoto, Kei

    2017-01-01

    Actin is a highly abundant protein in eukaryotic cells and dynamically changes its polymerized states with the help of actin-binding proteins. Its critical function as a constituent of cytoskeleton has been well-documented. Growing evidence demonstrates that actin is also present in nuclei, referred to as nuclear actin, and is involved in a number of nuclear processes, including transcriptional regulation and chromatin remodeling. The contribution of nuclear actin to transcriptional regulation can be explained by its direct interaction with transcription machineries and chromatin remodeling factors and by controlling the activities of transcription factors. In both cases, polymerized states of nuclear actin affect the transcriptional outcome. Nuclear actin also plays an important role in activating strongly silenced genes in somatic cells for transcriptional reprogramming. When these nuclear functions of actin are considered, it is plausible to speculate that nuclear actin is also implicated in embryonic development, in which numerous genes need to be activated in a well-coordinated manner. In this review, we especially focus on nuclear actin's roles in transcriptional activation, reprogramming and development, including stem cell differentiation and we discuss how nuclear actin can be an important player in development and cell differentiation.

  16. Germ line, stem cells, and epigenetic reprogramming.

    PubMed

    Surani, M A; Durcova-Hills, G; Hajkova, P; Hayashi, K; Tee, W W

    2008-01-01

    The germ cell lineage has the unique attribute of generating the totipotent state. Development of blastocysts from the totipotent zygote results in the establishment of pluripotent primitive ectoderm cells in the inner cell mass of blastocysts, which subsequently develop into epiblast cells in postimplantation embryos. The germ cell lineage in mice originates from these pluripotent epiblast cells of postimplantation embryos in response to specific signals. Pluripotent stem cells and unipotent germ cells share some fundamental properties despite significant phenotypic differences between them. Additionally, early primordial germ cells can be induced to undergo dedifferentiation into pluripotent embryonic germ cells. Investigations on the relationship between germ cells and pluripotent stem cells may further elucidate the nature of the pluripotent state. Furthermore, comprehensive epigenetic reprogramming of the genome in early germ cells, including extensive erasure of epigenetic modifications, is a critical step toward establishment of totipotency. The mechanisms involved may be relevant for gaining insight into events that lead to reprogramming of somatic cells into pluripotent stem cells.

  17. Shifting behaviour: epigenetic reprogramming in eusocial insects.

    PubMed

    Patalano, Solenn; Hore, Timothy A; Reik, Wolf; Sumner, Seirian

    2012-06-01

    Epigenetic modifications are ancient and widely utilised mechanisms that have been recruited across fungi, plants and animals for diverse but fundamental biological functions, such as cell differentiation. Recently, a functional DNA methylation system was identified in the honeybee, where it appears to underlie queen and worker caste differentiation. This discovery, along with other insights into the epigenetics of social insects, allows provocative analogies to be drawn between insect caste differentiation and cellular differentiation, particularly in mammals. Developing larvae in social insect colonies are totipotent: they retain the ability to specialise as queens or workers, in a similar way to the totipotent cells of early embryos before they differentiate into specific cell lineages. Further, both differentiating cells and insect castes lose phenotypic plasticity by committing to their lineage, losing the ability to be readily reprogrammed. Hence, a comparison of the epigenetic mechanisms underlying lineage differentiation (and reprogramming) between cells and social insects is worthwhile. Here we develop a conceptual model of how loss and regain of phenotypic plasticity might be conserved for individual specialisation in both cells and societies. This framework forges a novel link between two fields of biological research, providing predictions for a unified approach to understanding the molecular mechanisms underlying biological complexity.

  18. Nuclear Actin in Development and Transcriptional Reprogramming

    PubMed Central

    Misu, Shinji; Takebayashi, Marina; Miyamoto, Kei

    2017-01-01

    Actin is a highly abundant protein in eukaryotic cells and dynamically changes its polymerized states with the help of actin-binding proteins. Its critical function as a constituent of cytoskeleton has been well-documented. Growing evidence demonstrates that actin is also present in nuclei, referred to as nuclear actin, and is involved in a number of nuclear processes, including transcriptional regulation and chromatin remodeling. The contribution of nuclear actin to transcriptional regulation can be explained by its direct interaction with transcription machineries and chromatin remodeling factors and by controlling the activities of transcription factors. In both cases, polymerized states of nuclear actin affect the transcriptional outcome. Nuclear actin also plays an important role in activating strongly silenced genes in somatic cells for transcriptional reprogramming. When these nuclear functions of actin are considered, it is plausible to speculate that nuclear actin is also implicated in embryonic development, in which numerous genes need to be activated in a well-coordinated manner. In this review, we especially focus on nuclear actin’s roles in transcriptional activation, reprogramming and development, including stem cell differentiation and we discuss how nuclear actin can be an important player in development and cell differentiation. PMID:28326098

  19. Oncogenic regulation of tumor metabolic reprogramming

    PubMed Central

    Tarrado-Castellarnau, Míriam; de Atauri, Pedro; Cascante, Marta

    2016-01-01

    Development of malignancy is accompanied by a complete metabolic reprogramming closely related to the acquisition of most of cancer hallmarks. In fact, key oncogenic pathways converge to adapt the metabolism of carbohydrates, proteins, lipids and nucleic acids to the dynamic tumor microenvironment, conferring a selective advantage to cancer cells. Therefore, metabolic properties of tumor cells are significantly different from those of non-transformed cells. In addition, tumor metabolic reprogramming is linked to drug resistance in cancer treatment. Accordingly, metabolic adaptations are specific vulnerabilities that can be used in different therapeutic approaches for cancer therapy. In this review, we discuss the dysregulation of the main metabolic pathways that enable cell transformation and its association with oncogenic signaling pathways, focusing on the effects of c-MYC, hypoxia inducible factor 1 (HIF1), phosphoinositide-3-kinase (PI3K), and the mechanistic target of rapamycin (mTOR) on cancer cell metabolism. Elucidating these connections is of crucial importance to identify new targets and develop selective cancer treatments that improve response to therapy and overcome the emerging resistance to chemotherapeutics. PMID:28040803

  20. Demethylation of H3K27 Is Essential for the Induction of Direct Cardiac Reprogramming by miR Combo.

    PubMed

    Dal-Pra, Sophie; Hodgkinson, Conrad P; Mirotsou, Maria; Kirste, Imke; Dzau, Victor J

    2017-02-16

    Rationale: Direct reprogramming of cardiac fibroblasts to cardac omyocytes has recently emerged as a novel and promising approach to regenerate the injured myocardium. We have previously demonstrated the feasibility of this approach in vitro and in vivo using a combination of four microRNAs (miR-1, miR-133, miR-208 and miR-499) that we named miR combo. However, the mechanism of miR combo mediated direct cardiac reprogramming is currently unknown. Objective: Here we investigated the possibility that miR combo initiated direct cardiac reprogramming through an epigenetic mechanism. Methods and Results: Using a qPCR array, we found that histone methyltransferases and demethylases that regulate the tri-methylation of H3K27 (H3K27me3), an epigenetic modification that marks transcriptional repression, were changed in miR combo treated fibroblasts. Accordingly, global H3K27me3 levels were downregulated by miR combo treatment. In particular, the promoter region of cardiac transcription factors showed decreased H3K27me3 as revealed by ChIP-qPCR. Inhibition of H3K27 methyltransferases or of the Polycomb Repressive Complex 2 (PRC2) by pharmaceutical inhibition or siRNA reduced the levels of H3K27me3 and induced cardiogenic markers at the RNA and protein level, similarly to miR combo treatment. In contrast, knockdown of the H3K27 demethylases Kdm6A and Kdm6B restored the levels of H3K27me3 and blocked the induction of cardiac gene expression in miR combo treated fibroblasts. Conclusions: In summary, we demonstrated that removal of the repressive mark H3K27me3 is essential for the induction of cardiac reprogramming by miR combo. Our data not only highlight the importance of regulating the epigenetic landscape during cell fate conversion but also provide a framework to improve this technique.

  1. Reprogramming mitochondrial metabolism in macrophages as an anti-inflammatory signal.

    PubMed

    Mills, Evanna L; O'Neill, Luke A

    2016-01-01

    Mitochondria are master regulators of metabolism. Mitochondria generate ATP by oxidative phosphorylation using pyruvate (derived from glucose and glycolysis) and fatty acids (FAs), both of which are oxidized in the Krebs cycle, as fuel sources. Mitochondria are also an important source of reactive oxygen species (ROS), creating oxidative stress in various contexts, including in the response to bacterial infection. Recently, complex changes in mitochondrial metabolism have been characterized in mouse macrophages in response to varying stimuli in vitro. In LPS and IFN-γ-activated macrophages (M1 macrophages), there is decreased respiration and a broken Krebs cycle, leading to accumulation of succinate and citrate, which act as signals to alter immune function. In IL-4-activated macrophages (M2 macrophages), the Krebs cycle and oxidative phosphorylation are intact and fatty acid oxidation (FAO) is also utilized. These metabolic alterations in response to the nature of the stimulus are proving to be determinants of the effector functions of M1 and M2 macrophages. Furthermore, reprogramming of macrophages from M1 to M2 can be achieved by targeting metabolic events. Here, we describe the role that metabolism plays in macrophage function in infection and immunity, and propose that reprogramming with metabolic inhibitors might be a novel therapeutic approach for the treatment of inflammatory diseases.

  2. Epigenetic reprogramming and small RNA silencing of transposable elements in pollen

    PubMed Central

    Slotkin, R. Keith; Vaughn, Matthew; Tanurdžic, Miloš; Borges, Filipe; Becker, Jörg D.; Feijó, José A.; Martienssen, Robert A.

    2009-01-01

    Summary The mutagenic activity of transposable elements (TEs) is suppressed by epigenetic silencing and small interfering RNAs (siRNAs), especially in gametes that would transmit transposed elements to the next generation. In pollen from the model plant Arabidopsis, we show that TEs are unexpectedly reactivated and transpose, but only in the pollen vegetative nucleus, which accompanies the sperm cells but does not provide DNA to the fertilized zygote. TE expression coincides with down-regulation of the heterochromatin remodeler DECREASE IN DNA METHYLATION 1 and of most TE siRNAs. However, 21 nucleotide siRNA from Athila retrotransposons is generated in pollen and accumulates in sperm, indicating that siRNA from TEs activated in the vegetative nucleus can target silencing in gametes. We propose a conserved role for reprogramming in germline companion cells, such as nurse cells in insects and vegetative nuclei in plants, to reveal intact TEs in the genome and regulate their activity in gametes. PMID:19203581

  3. Concurrent progress of reprogramming and gene correction to overcome therapeutic limitation of mutant ALK2-iPSC

    PubMed Central

    Kim, Bu-Yeo; Jeong, SangKyun; Lee, Seo-Young; Lee, So Min; Gweon, Eun Jeong; Ahn, Hyunjun; Kim, Janghwan; Chung, Sun-Ku

    2016-01-01

    Fibrodysplasia ossificans progressiva (FOP) syndrome is caused by mutation of the gene ACVR1, encoding a constitutive active bone morphogenetic protein type I receptor (also called ALK2) to induce heterotopic ossification in the patient. To genetically correct it, we attempted to generate the mutant ALK2-iPSCs (mALK2-iPSCs) from FOP-human dermal fibroblasts. However, the mALK2 leads to inhibitory pluripotency maintenance, or impaired clonogenic potential after single-cell dissociation as an inevitable step, which applies gene-correction tools to induced pluripotent stem cells (iPSCs). Thus, current iPSC-based gene therapy approach reveals a limitation that is not readily applicable to iPSCs with ALK2 mutation. Here we developed a simplified one-step procedure by simultaneously introducing reprogramming and gene-editing components into human fibroblasts derived from patient with FOP syndrome, and genetically treated it. The mixtures of reprogramming and gene-editing components are composed of reprogramming episomal vectors, CRISPR/Cas9-expressing vectors and single-stranded oligodeoxynucleotide harboring normal base to correct ALK2 c.617G>A. The one-step-mediated ALK2 gene-corrected iPSCs restored global gene expression pattern, as well as mineralization to the extent of normal iPSCs. This procedure not only helps save time, labor and costs but also opens up a new paradigm that is beyond the current application of gene-editing methodologies, which is hampered by inhibitory pluripotency-maintenance requirements, or vulnerability of single-cell-dissociated iPSCs. PMID:27256111

  4. Integrating Gene Correction in the Reprogramming and Transdifferentiation Processes: A One-Step Strategy to Overcome Stem Cell-Based Gene Therapy Limitations.

    PubMed

    Lee, Seo-Young; Chung, Sun-Ku

    2016-01-01

    The recent advent of induced pluripotent stem cells (iPSCs) and gene therapy tools has raised the possibility of autologous cell therapy for rare genetic diseases. However, cellular reprogramming is inefficient in certain diseases such as ataxia telangiectasia, Fanconi anemia, LIG4 syndrome, and fibrodysplasia ossificans progressiva syndrome, owing to interference of the disease-related genes. To overcome these therapeutic limitations, it is necessary to fundamentally correct the abnormal gene during or prior to the reprogramming process. In addition, as genetic etiology of Parkinson's disease, it has been well known that induced neural stem cells (iNSCs) were progressively depleted by LRRK2 gene mutation, LRRK2 (G2019S). Thus, to maintain the induced NSCs directly derived from PD patient cells harboring LRRK2 (G2019S), it would be ideal to simultaneously treat the LRRK2 (G2019S) fibroblast during the process of TD. Therefore, simultaneous reprogramming (or TD) and gene therapy would provide the solution for therapeutic limitation caused by vulnerability of reprogramming or TD, in addition to being suitable for general application to the generation of autologous cell-therapy products for patients with genetic defects, thereby obviating the need for the arduous processes currently required.

  5. Integrating Gene Correction in the Reprogramming and Transdifferentiation Processes: A One-Step Strategy to Overcome Stem Cell-Based Gene Therapy Limitations

    PubMed Central

    Lee, Seo-Young

    2016-01-01

    The recent advent of induced pluripotent stem cells (iPSCs) and gene therapy tools has raised the possibility of autologous cell therapy for rare genetic diseases. However, cellular reprogramming is inefficient in certain diseases such as ataxia telangiectasia, Fanconi anemia, LIG4 syndrome, and fibrodysplasia ossificans progressiva syndrome, owing to interference of the disease-related genes. To overcome these therapeutic limitations, it is necessary to fundamentally correct the abnormal gene during or prior to the reprogramming process. In addition, as genetic etiology of Parkinson's disease, it has been well known that induced neural stem cells (iNSCs) were progressively depleted by LRRK2 gene mutation, LRRK2 (G2019S). Thus, to maintain the induced NSCs directly derived from PD patient cells harboring LRRK2 (G2019S), it would be ideal to simultaneously treat the LRRK2 (G2019S) fibroblast during the process of TD. Therefore, simultaneous reprogramming (or TD) and gene therapy would provide the solution for therapeutic limitation caused by vulnerability of reprogramming or TD, in addition to being suitable for general application to the generation of autologous cell-therapy products for patients with genetic defects, thereby obviating the need for the arduous processes currently required. PMID:28074097

  6. Regulation of L-threonine dehydrogenase in somatic cell reprogramming.

    PubMed

    Han, Chuanchun; Gu, Hao; Wang, Jiaxu; Lu, Weiguang; Mei, Yide; Wu, Mian

    2013-05-01

    Increasing evidence suggests that metabolic remodeling plays an important role in the regulation of somatic cell reprogramming. Threonine catabolism mediated by L-threonine dehydrogenase (TDH) has been recognized as a specific metabolic trait of mouse embryonic stem cells. However, it remains unknown whether TDH-mediated threonine catabolism could regulate reprogramming. Here, we report TDH as a novel regulator of somatic cell reprogramming. Knockdown of TDH inhibits, whereas induction of TDH enhances reprogramming efficiency. Moreover, microRNA-9 post-transcriptionally regulates the expression of TDH and thereby inhibits reprogramming efficiency. Furthermore, protein arginine methyltransferase (PRMT5) interacts with TDH and mediates its post-translational arginine methylation. PRMT5 appears to regulate TDH enzyme activity through both methyltransferase-dependent and -independent mechanisms. Functionally, TDH-facilitated reprogramming efficiency is further enhanced by PRMT5. These results suggest that TDH-mediated threonine catabolism controls somatic cell reprogramming and indicate the importance of post-transcriptional and post-translational regulation of TDH.

  7. Deterministic direct reprogramming of somatic cells to pluripotency.

    PubMed

    Rais, Yoach; Zviran, Asaf; Geula, Shay; Gafni, Ohad; Chomsky, Elad; Viukov, Sergey; Mansour, Abed AlFatah; Caspi, Inbal; Krupalnik, Vladislav; Zerbib, Mirie; Maza, Itay; Mor, Nofar; Baran, Dror; Weinberger, Leehee; Jaitin, Diego A; Lara-Astiaso, David; Blecher-Gonen, Ronnie; Shipony, Zohar; Mukamel, Zohar; Hagai, Tzachi; Gilad, Shlomit; Amann-Zalcenstein, Daniela; Tanay, Amos; Amit, Ido; Novershtern, Noa; Hanna, Jacob H

    2013-10-03

    Somatic cells can be inefficiently and stochastically reprogrammed into induced pluripotent stem (iPS) cells by exogenous expression of Oct4 (also called Pou5f1), Sox2, Klf4 and Myc (hereafter referred to as OSKM). The nature of the predominant rate-limiting barrier(s) preventing the majority of cells to successfully and synchronously reprogram remains to be defined. Here we show that depleting Mbd3, a core member of the Mbd3/NuRD (nucleosome remodelling and deacetylation) repressor complex, together with OSKM transduction and reprogramming in naive pluripotency promoting conditions, result in deterministic and synchronized iPS cell reprogramming (near 100% efficiency within seven days from mouse and human cells). Our findings uncover a dichotomous molecular function for the reprogramming factors, serving to reactivate endogenous pluripotency networks while simultaneously directly recruiting the Mbd3/NuRD repressor complex that potently restrains the reactivation of OSKM downstream target genes. Subsequently, the latter interactions, which are largely depleted during early pre-implantation development in vivo, lead to a stochastic and protracted reprogramming trajectory towards pluripotency in vitro. The deterministic reprogramming approach devised here offers a novel platform for the dissection of molecular dynamics leading to establishing pluripotency at unprecedented flexibility and resolution.

  8. The expanding horizon of MicroRNAs in cellular reprogramming.

    PubMed

    Adlakha, Yogita K; Seth, Pankaj

    2017-01-01

    Research over the last few years in cellular reprogramming has enlightened the magical potential of microRNAs (miRNAs) in changing the cell fate from somatic to pluripotent. Recent investigations on exploring the role(s) of miRNAs in somatic cell reprogramming revealed that they target a wide range of molecules and refine their protein output. This leads to fine tuning of distinct cellular processes including cell cycle, signalling pathways, transcriptional activation/silencing and epigenetic modelling. The concerted actions of miRNA on different pathways simultaneously strengthen the transition from a differentiated to de-differentiated state. Despite the well characterized transcriptional and epigenetic machinery underlying somatic cell reprogramming, the molecular circuitry for miRNA mediated cellular reprogramming is rather fragmented. This review summarizes recent findings addressing the role of miRNAs in inducing or suppressing reprogramming thus uncovering novel potentials of miRNAs as regulators of induced pluripotency maintenance, establishment and associated signalling pathways. Our bioinformatic analysis sheds light on various unexplored biological processes and pathways associated with reprogramming inducing miRNAs, thus helps in identifying roadblocks to full reprogramming. Specifically, the biological significance of highly conserved and most studied miRNA cluster, i.e. miR-302-367, in reprogramming is also highlighted. Further, roles of miRNAs in the differentiation of neurons from iPSCs are discussed. A recent approach of direct conversion or transdifferentiation of differentiated cells into neurons by miRNAs is also elaborated. This approach is now widely gaining impetus for the generation of neurological patient's brain cells directly from his/her somatic cells in an efficient and safe manner. Thus, decoding the intricate circuitry between miRNAs and other gene regulatory networks will not only uncover novel pathways in the direct reprogramming of

  9. Direct neuronal reprogramming: learning from and for development.

    PubMed

    Masserdotti, Giacomo; Gascón, Sergio; Götz, Magdalena

    2016-07-15

    The key signalling pathways and transcriptional programmes that instruct neuronal diversity during development have largely been identified. In this Review, we discuss how this knowledge has been used to successfully reprogramme various cell types into an amazing array of distinct types of functional neurons. We further discuss the extent to which direct neuronal reprogramming recapitulates embryonic development, and examine the particular barriers to reprogramming that may exist given a cell's unique developmental history. We conclude with a recently proposed model for cell specification called the 'Cook Islands' model, and consider whether it is a fitting model for cell specification based on recent results from the direct reprogramming field.

  10. Transdifferentiation: a cell and molecular reprogramming process.

    PubMed

    Sisakhtnezhad, Sajjad; Matin, Maryam M

    2012-06-01

    Evidence has emerged recently indicating that differentiation is not entirely a one-way process, and that it is possible to convert one cell type to another, both in vitro and in vivo. This phenomenon is called transdifferentiation, and is generally defined as the stable switch of one cell type to another. Transdifferentiation plays critical roles during development and in regeneration pathways in nature. Although this phenomenon occurs rarely in nature, recent studies have been focused on transdifferentiation and the reprogramming ability of cells to produce specific cells with new phenotypes for use in cell therapy and regenerative medicine. Thus, understanding the principles and the mechanism of this process is important for producing desired cell types. Here some well-documented examples of transdifferentiation, and their significance in development and regeneration are reviewed. In addition, transdifferentiation pathways are considered and their potential molecular mechanisms, especially the role of master switch genes, are considered. Finally, the significance of transdifferentiation in regenerative medicine is discussed.

  11. Targeting Lipid Metabolic Reprogramming as Anticancer Therapeutics

    PubMed Central

    Cha, Ji-Young; Lee, Ho-Jae

    2016-01-01

    Cancer cells rewire their metabolism to satisfy the demands of growth and survival, and this metabolic reprogramming has been recognized as an emerging hallmark of cancer. Lipid metabolism is pivotal in cellular process that converts nutrients into energy, building blocks for membrane biogenesis and the generation of signaling molecules. Accumulating evidence suggests that cancer cells show alterations in different aspects of lipid metabolism. The changes in lipid metabolism of cancer cells can affect numerous cellular processes, including cell growth, proliferation, differentiation, and survival. The potential dependence of cancer cells on the deregulated lipid metabolism suggests that enzymes and regulating factors involved in this process are promising targets for cancer treatment. In this review, we focus on the features associated with the lipid metabolic pathways in cancer, and highlight recent advances on the therapeutic targets of specific lipid metabolic enzymes or regulating factors and target-directed small molecules that can be potentially used as anticancer drugs. PMID:28053954

  12. Programming and reprogramming a human heart cell.

    PubMed

    Sahara, Makoto; Santoro, Federica; Chien, Kenneth R

    2015-03-12

    The latest discoveries and advanced knowledge in the fields of stem cell biology and developmental cardiology hold great promise for cardiac regenerative medicine, enabling researchers to design novel therapeutic tools and approaches to regenerate cardiac muscle for diseased hearts. However, progress in this arena has been hampered by a lack of reproducible and convincing evidence, which at best has yielded modest outcomes and is still far from clinical practice. To address current controversies and move cardiac regenerative therapeutics forward, it is crucial to gain a deeper understanding of the key cellular and molecular programs involved in human cardiogenesis and cardiac regeneration. In this review, we consider the fundamental principles that govern the "programming" and "reprogramming" of a human heart cell and discuss updated therapeutic strategies to regenerate a damaged heart.

  13. Intact capture of hypervelocity projectiles

    NASA Technical Reports Server (NTRS)

    Tsou, P.

    1990-01-01

    The ability to capture projectiles intact at hypervelocities opens new applications in science and technology that would either not be possible or would be very costly by other means. This capability has been demonstrated in the laboratory for aluminum projectiles of 1.6 mm diameter, captured at 6 km/s, in one unmelted piece, and retaining up to 95% of the original mass. Furthermore, capture was accomplished passively using microcellular underdense polymer foam. Another advantage of capturing projectiles in an underdense medium is the ability of such a medium to preserve a record of the projectile's original velocity components of speed and direction. A survey of these experimental results is described in terms of a dozen parameters which characterize the amount of capture and the effect on the projectile due to different capture media.

  14. Intact capture of hypervelocity projectiles.

    PubMed

    Tsou, P

    1990-01-01

    The ability to capture projectiles intact at hypervelocities opens new applications in science and technology that would either not be possible or would be very costly by other means. This capability has been demonstrated in the laboratory for aluminum projectiles of 1.6 mm diameter, captured at 6 km/s, in one unmelted piece, and retaining up to 95% of the original mass. Furthermore, capture was accomplished passively using microcellular underdense polymer foam. Another advantage of capturing projectiles in an underdense medium is the ability of such a medium to preserve a record of the projectile's original velocity components of speed and direction. A survey of these experimental results is described in terms of a dozen parameters which characterize the amount of capture and the effect on the projectile due to different capture media.

  15. Generation of iPSC line iPSC-FH2.1 in hypoxic conditions from human foreskin fibroblasts.

    PubMed

    Questa, María; Romorini, Leonardo; Blüguermann, Carolina; Solari, Claudia María; Neiman, Gabriel; Luzzani, Carlos; Scassa, María Élida; Sevlever, Gustavo Emilio; Guberman, Alejandra Sonia; Miriuka, Santiago Gabriel

    2016-03-01

    Human foreskin fibroblasts were used to generate the iPSC line iPSC-FH2.1 using the EF1a-hSTEMCCA-loxP vector expressing OCT4, SOX2, c-MYC and KLF4, in 5% O2 culture conditions. Stemness was confirmed, as was pluripotency both in vivo and in vitro, in normoxia and hypoxia. Human Embryonic Stem Cell (hESC) line WA-09 and reprogrammed fibroblast primary culture HFF-FM were used as controls.

  16. The expression of pluripotency genes and neuronal markers after neurodifferentiation in fibroblasts co-cultured with human umbilical cord blood mononuclear cells.

    PubMed

    Marinowic, D R; Domingues, M F; Machado, D C; DaCosta, J C

    2015-01-01

    Human umbilical cord blood is an attractive source of stem cells; however, it has a heterogeneous cell population with few mesenchymal stem cells. Cell reprogramming induced by different methodologies can confer pluripotency to differentiated adult cells. The objective of this study was to evaluate the reprogramming of fibroblasts and their subsequent neural differentiation after co-culture with umbilical cord blood mononuclear cells. Cells were obtained from four human umbilical cords. The mononuclear cells were cultured for 7 d and subsequently co-cultured with mouse fibroblast NIH-3T3 cells for 6 d. The pluripotency of the cells was evaluated by RT-PCR using primers specific for pluripotency marker genes. The pluripotency was also confirmed by adipogenic and osteogenic differentiation. Neural differentiation of the reprogrammed cells was evaluated by immunofluorescence. All co-cultured cells showed adipogenic and osteogenic differentiation capacity. After co-cultivation, cells expressed the pluripotency gene KLF4. Statistically significant differences in cell area, diameter, optical density, and fractal dimension were observed by confocal microscopy in the neurally differentiated cells. Contact in the form of co-cultivation of fibroblasts with umbilical cord blood mononuclear fraction for 6 d promoted the reprogramming of these cells, allowing the later induction of neural differentiation.

  17. Dupuytren's Contracture: Fibroblast Contraction?

    PubMed Central

    Gabbiani, Giulio; Majno, Guido

    1972-01-01

    In 6 cases of Dupuytren's disease and 1 of Ledderhose's disease, the nodules of the palmar and plantar aponeurosis were examined by light and electron microscopy. The cells composing these nodules, presumably fibroblasts, showed three significant ultrastructural features: (1) a fibrillar system similar to that of smooth muscle cells; (2) nuclear deformations such as are found in contracted cells, the severest being recognizable by light microscopy (cross-banded nuclei); (3) cell-to-cell and cell-to-stroma attachments. Based on these data and on recent information about the biology of the fibroblasts, it is suggested that these cells are fibroblasts that have modulated into contractile cells (myofibroblasts), and that their contraction plays a role in the pathogenesis of the contracture observed clinically. ImagesFig 10Fig 5Fig 11Fig 6 and 7Fig 8Fig 1Fig 2Fig 9Fig 3Fig 4 PMID:5009249

  18. Class IIa Histone Deacetylases and Myocyte Enhancer Factor 2 Proteins Regulate the Mesenchymal-to-Epithelial Transition of Somatic Cell Reprogramming*

    PubMed Central

    Zhuang, Qiang; Qing, Xiaobing; Ying, Yue; Wu, Haitao; Benda, Christina; Lin, Jiao; Huang, Zhijian; Liu, Longqi; Xu, Yan; Bao, Xichen; Qin, Baoming; Pei, Duanqing; Esteban, Miguel A.

    2013-01-01

    Class IIa histone deacetylases (HDACs) and myocyte enhancer factor 2 (MEF2) proteins compose a signaling module that orchestrates lineage specification during embryogenesis. We show here that this module also regulates the generation of mouse induced pluripotent stem cells by defined transcription factors. Class IIa HDACs and MEF2 proteins rise steadily during fibroblast reprogramming to induced pluripotent stem cells. MEF2 proteins tend to block the process by inducing the expression of Tgfβ cytokines, which impairs the necessary phase of mesenchymal-to-epithelial transition (MET). Conversely, class IIa HDACs endeavor to suppress the activity of MEF2 proteins, thus enhancing the MET and colony formation efficiency. Our work highlights an unexpected role for a developmental axis in somatic cell reprogramming and provides new insight into how the MET is regulated in this context. PMID:23467414

  19. Nuclear reprogramming and its role in vascular smooth muscle cells.

    PubMed

    Zaina, Silvio; del Pilar Valencia-Morales, Maria; Tristán-Flores, Fabiola E; Lund, Gertrud

    2013-09-01

    In general terms, "nuclear reprogramming" refers to a change in gene expression profile that results in a significant switch in cellular phenotype. Nuclear reprogramming was first addressed by pioneering studies of cell differentiation during embryonic development. In recent years, nuclear reprogramming has been studied in great detail in the context of experimentally controlled dedifferentiation and transdifferentiation of mammalian cells for therapeutic purposes. In this review, we present a perspective on nuclear reprogramming in the context of spontaneous, pathophysiological phenotypic switch of vascular cells occurring in the atherosclerotic lesion. In particular, we focus on the current knowledge of epigenetic mechanisms participating in the extraordinary flexibility of the gene expression profile of vascular smooth muscle cells and other cell types participating in atherogenesis. Understanding how epigenetic changes participate in vascular cell plasticity may lead to effective therapies based on the remodelling of the vascular architecture.

  20. A Cell Electrofusion Chip for Somatic Cells Reprogramming

    PubMed Central

    Wu, Wei; Zeng, Yuxiao; Yang, Jun; Xu, Haiwei; Yin, Zheng Qin

    2015-01-01

    Cell fusion is a potent approach to explore the mechanisms of somatic cells reprogramming. However, previous fusion methods, such as polyethylene glycol (PEG) mediated cell fusion, are often limited by poor fusion yields. In this study, we developed a simplified cell electrofusion chip, which was based on a micro-cavity/ discrete microelectrode structure to improve the fusion efficiency and to reduce multi-cell electrofusion. Using this chip, we could efficiently fuse NIH3T3 cells and mouse embryonic stem cells (mESCs) to induce somatic cells reprogramming. We also found that fused cells demethylated gradually and 5-hydroxymethylcytosine (5hmC) was involved in the demethylation during the reprogramming. Thus, the cell electrofusion chip would facilitate reprogramming mechanisms research by improving efficiency of cell fusion and reducing workloads. PMID:26177036

  1. Genetic background affects susceptibility to tumoral stem cell reprogramming

    PubMed Central

    García-Ramírez, Idoia; Ruiz-Roca, Lucía; Martín-Lorenzo, Alberto; Blanco, Óscar; García-Cenador, María Begoña; García-Criado, Francisco Javier; Vicente-Dueñas, Carolina; Sánchez-García, Isidro

    2013-01-01

    The latest studies of the interactions between oncogenes and its target cell have shown that certain oncogenes may act as passengers to reprogram tissue-specific stem/progenitor cell into a malignant cancer stem cell state. In this study, we show that the genetic background influences this tumoral stem cell reprogramming capacity of the oncogenes using as a model the Sca1-BCRABLp210 mice, where the type of tumor they develop, chronic myeloid leukemia (CML), is a function of tumoral stem cell reprogramming. Sca1-BCRABLp210 mice containing FVB genetic components were significantly more resistant to CML. However, pure Sca1-BCRABLp210 FVB mice developed thymomas that were not seen in the Sca1-BCRABLp210 mice into the B6 background. Collectively, our results demonstrate for the first time that tumoral stem cell reprogramming fate is subject to polymorphic genetic control. PMID:23839033

  2. Reprogramming to pluripotency: from frogs to stem cells.

    PubMed

    Rossant, Janet

    2009-09-18

    This year's Albert Lasker Basic Medical Research Award goes to John Gurdon and Shinya Yamanaka for their contributions to our understanding of how to reprogram adult cells back to early embryonic states.

  3. Reprogramming of human exocrine pancreas cells to beta cells.

    PubMed

    Staels, Willem; Heremans, Yves; Heimberg, Harry

    2015-12-01

    One of the key promises of regenerative medicine is providing a cure for diabetes. Cell-based therapies are proving their safety and efficiency, but donor beta cell shortages and immunological issues remain major hurdles. Reprogramming of human pancreatic exocrine cells towards beta cells would offer a major advantage by providing an abundant and autologous source of beta cells. Over the past decade our understanding of transdifferentiation processes greatly increased allowing us to design reprogramming protocols that fairly aim for clinical trials.

  4. Understanding Parkinson's Disease through the Use of Cell Reprogramming.

    PubMed

    Playne, Rebecca; Connor, Bronwen

    2017-04-01

    Recent progress in the field of somatic cell reprogramming offers exciting new possibilities for the study and treatment of Parkinson's disease (PD). Reprogramming technology offers the ability to untangle the diverse contributing risk factors for PD, such as ageing, genetics and environmental toxins. In order to gain novel insights into such a complex disease, cell-based models of PD should represent, as closely as possible, aged human dopaminergic neurons of the substantia nigra. However, the generation of high yields of functionally mature, authentic ventral midbrain dopamine (vmDA) neurons has not been easy to achieve. Furthermore, ensuring cells represent aged rather than embryonic neurons has presented a significant challenge. To date, induced pluripotent stem (iPS) cells have received much attention for modelling PD. Nonetheless, direct reprogramming strategies (either to a neuronal or neural stem/progenitor fate) represent a valid alternative that are yet to be extensively explored. Direct reprogramming is faster and more efficient than iPS cell reprogramming, and appears to conserve age-related markers. At present, however, protocols aiming to derive authentic, mature vmDA neurons by direct reprogramming of adult human somatic cells are sorely lacking. This review will discuss the strategies that have been employed to generate vmDA neurons and their potential for the study and treatment of PD.

  5. Advances in reprogramming-based study of neurologic disorders.

    PubMed

    Nityanandam, Anjana; Baldwin, Kristin K

    2015-06-01

    The technology to convert adult human non-neural cells into neural lineages, through induced pluripotent stem cells (iPSCs), somatic cell nuclear transfer, and direct lineage reprogramming or transdifferentiation has progressed tremendously in recent years. Reprogramming-based approaches aimed at manipulating cellular identity have enormous potential for disease modeling, high-throughput drug screening, cell therapy, and personalized medicine. Human iPSC (hiPSC)-based cellular disease models have provided proof of principle evidence of the validity of this system. However, several challenges remain before patient-specific neurons produced by reprogramming can provide reliable insights into disease mechanisms or be efficiently applied to drug discovery and transplantation therapy. This review will first discuss limitations of currently available reprogramming-based methods in faithfully and reproducibly recapitulating disease pathology. Specifically, we will address issues such as culture heterogeneity, interline and inter-individual variability, and limitations of two-dimensional differentiation paradigms. Second, we will assess recent progress and the future prospects of reprogramming-based neurologic disease modeling. This includes three-dimensional disease modeling, advances in reprogramming technology, prescreening of hiPSCs and creating isogenic disease models using gene editing.

  6. Advances in Reprogramming-Based Study of Neurologic Disorders

    PubMed Central

    Baldwin, Kristin K.

    2015-01-01

    The technology to convert adult human non-neural cells into neural lineages, through induced pluripotent stem cells (iPSCs), somatic cell nuclear transfer, and direct lineage reprogramming or transdifferentiation has progressed tremendously in recent years. Reprogramming-based approaches aimed at manipulating cellular identity have enormous potential for disease modeling, high-throughput drug screening, cell therapy, and personalized medicine. Human iPSC (hiPSC)-based cellular disease models have provided proof of principle evidence of the validity of this system. However, several challenges remain before patient-specific neurons produced by reprogramming can provide reliable insights into disease mechanisms or be efficiently applied to drug discovery and transplantation therapy. This review will first discuss limitations of currently available reprogramming-based methods in faithfully and reproducibly recapitulating disease pathology. Specifically, we will address issues such as culture heterogeneity, interline and inter-individual variability, and limitations of two-dimensional differentiation paradigms. Second, we will assess recent progress and the future prospects of reprogramming-based neurologic disease modeling. This includes three-dimensional disease modeling, advances in reprogramming technology, prescreening of hiPSCs and creating isogenic disease models using gene editing. PMID:25749371

  7. Triton shells of intact erythrocytes.

    PubMed

    Sheetz, M P; Sawyer, D

    1978-01-01

    About 40% of human erythrocyte membrane protein is resistant to solubilization in 0.5% Triton X-114. These components comprise a structure called a Triton shell roughly similar in size and shape to the original erythrocyte and thus constitute a cytoskeleton. With increasing concentrations of Triton the lipid content of the Triton shell decreases dramatically, whereas the majority of the protein components remain constant. Exceptions to this rule include proteins contained in band 3, the presumed anion channel, and in band 4 which decrease with increasing Triton concentration. The Triton-insoluble complex includes spectrin (bands 1 and 2), actin (band 5), and bands 3' and 7. Component 3' has an apparent molecular weight of 88,000 daltons as does 3; but unlike 3, it is insensitive to protease treatment of the intact cell, has a low extinction coefficient at 280 nm, and is solubilized from the shells in alkaline water solutions. Component 7 also has a low extinction coefficient at 280 nm. Spectrin alone is solubilized from the Triton shells in isotonic media. The solubilized spectrin contains no bound Triton and coelectrophoreses with spectrin eluted in hypotonic solutions from ghosts. Electron micrographs of fixed Triton shells stained with uranyl acetate show the presence of numerous filaments which appear beaded and are 80--120 A in diameter. The filaments cannot be composed mainly af actin, but enough spectrin is present to form the filaments. Triton shells may provide an excellent source of material useful in the investigation of the erythrocyte cytoskeleton.

  8. A synthetic small molecule for rapid induction of multiple pluripotency genes in mouse embryonic fibroblasts

    NASA Astrophysics Data System (ADS)

    Pandian, Ganesh N.; Nakano, Yusuke; Sato, Shinsuke; Morinaga, Hironobu; Bando, Toshikazu; Nagase, Hiroki; Sugiyama, Hiroshi

    2012-07-01

    Cellular reprogramming involves profound alterations in genome-wide gene expression that is precisely controlled by a hypothetical epigenetic code. Small molecules have been shown to artificially induce epigenetic modifications in a sequence independent manner. Recently, we showed that specific DNA binding hairpin pyrrole-imidazole polyamides (PIPs) could be conjugated with chromatin modifying histone deacetylase inhibitors like SAHA to epigenetically activate certain pluripotent genes in mouse fibroblasts. In our steadfast progress to improve the efficiency of SAHA-PIPs, we identified a novel compound termed, δ that could dramatically induce the endogenous expression of Oct-3/4 and Nanog. Genome-wide gene analysis suggests that in just 24 h and at nM concentration, δ induced multiple pluripotency-associated genes including Rex1 and Cdh1 by more than ten-fold. δ treated MEFs also rapidly overcame the rate-limiting step of epithelial transition in cellular reprogramming by switching ``'' the complex transcriptional gene network.

  9. Activity of PLCε contributes to chemotaxis of fibroblasts towards PDGF

    PubMed Central

    Martins, Marta; Warren, Sean; Kimberley, Christopher; Margineanu, Anca; Peschard, Pascal; McCarthy, Afshan; Yeo, Maggie; Marshall, Christopher J.; Dunsby, Christopher; French, Paul M. W.; Katan, Matilda

    2012-01-01

    Summary Cell chemotaxis, such as migration of fibroblasts towards growth factors during development and wound healing, requires precise spatial coordination of signalling events. Phosphoinositides and signalling enzymes involved in their generation and hydrolysis have been implicated in regulation of chemotaxis; however, the role and importance of specific components remain poorly understood. Here, we demonstrate that phospholipase C epsilon (PLCε) contributes to fibroblast chemotaxis towards platelet-derived growth factor (PDGF-BB). Using PLCe1 null fibroblasts we show that cells deficient in PLCε have greatly reduced directionality towards PDGF-BB without detrimental effect on their basal ability to migrate. Furthermore, we show that in intact fibroblasts, signalling events, such as activation of Rac, are spatially compromised by the absence of PLCε that affects the ability of cells to enlarge their protrusions in the direction of the chemoattractant. By further application of live cell imaging and the use of FRET-based biosensors, we show that generation of Ins(1,4,5)P3 and recruitment of PLCε are most pronounced in protrusions responding to the PDGF-BB gradient. Furthermore, the phospholipase C activity of PLCε is critical for its role in chemotaxis, consistent with the importance of Ins(1,4,5)P3 generation and sustained calcium responses in this process. As PLCε has extensive signalling connectivity, using transgenic fibroblasts we ruled out its activation by direct binding to Ras or Rap GTPases, and suggest instead new unexpected links for PLCε in the context of chemotaxis. PMID:22992460

  10. Cyclodextrin promotes atherosclerosis regression via macrophage reprogramming

    PubMed Central

    Zimmer, Sebastian; Grebe, Alena; Bakke, Siril S.; Bode, Niklas; Halvorsen, Bente; Ulas, Thomas; Skjelland, Mona; De Nardo, Dominic; Labzin, Larisa I.; Kerksiek, Anja; Hempel, Chris; Heneka, Michael T.; Hawxhurst, Victoria; Fitzgerald, Michael L; Trebicka, Jonel; Gustafsson, Jan-Åke; Westerterp, Marit; Tall, Alan R.; Wright, Samuel D.; Espevik, Terje; Schultze, Joachim L.; Nickenig, Georg; Lütjohann, Dieter; Latz, Eicke

    2016-01-01

    Atherosclerosis is an inflammatory disease linked to elevated blood cholesterol levels. Despite ongoing advances in the prevention and treatment of atherosclerosis, cardiovascular disease remains the leading cause of death worldwide. Continuous retention of apolipoprotein B-containing lipoproteins in the subendothelial space causes a local overabundance of free cholesterol. Since cholesterol accumulation and deposition of cholesterol crystals (CCs) triggers a complex inflammatory response, we tested the efficacy of the cyclic oligosaccharide 2-hydroxypropyl-β-cyclodextrin (CD), a compound that increases cholesterol solubility, in preventing and reversing atherosclerosis. Here we show that CD treatment of murine atherosclerosis reduced atherosclerotic plaque size and CC load, and promoted plaque regression even with a continued cholesterol-rich diet. Mechanistically, CD increased oxysterol production in both macrophages and human atherosclerotic plaques, and promoted liver X receptor (LXR)-mediated transcriptional reprogramming to improve cholesterol efflux and exert anti-inflammatory effects. In vivo, this CD-mediated LXR agonism was required for the anti-atherosclerotic and anti-inflammatory effects of CD as well as for augmented reverse cholesterol transport. Since CD treatment in humans is safe and CD beneficially affects key mechanisms of atherogenesis, it may therefore be used clinically to prevent or treat human atherosclerosis. PMID:27053774

  11. Cyclodextrin promotes atherosclerosis regression via macrophage reprogramming.

    PubMed

    Zimmer, Sebastian; Grebe, Alena; Bakke, Siril S; Bode, Niklas; Halvorsen, Bente; Ulas, Thomas; Skjelland, Mona; De Nardo, Dominic; Labzin, Larisa I; Kerksiek, Anja; Hempel, Chris; Heneka, Michael T; Hawxhurst, Victoria; Fitzgerald, Michael L; Trebicka, Jonel; Björkhem, Ingemar; Gustafsson, Jan-Åke; Westerterp, Marit; Tall, Alan R; Wright, Samuel D; Espevik, Terje; Schultze, Joachim L; Nickenig, Georg; Lütjohann, Dieter; Latz, Eicke

    2016-04-06

    Atherosclerosis is an inflammatory disease linked to elevated blood cholesterol concentrations. Despite ongoing advances in the prevention and treatment of atherosclerosis, cardiovascular disease remains the leading cause of death worldwide. Continuous retention of apolipoprotein B-containing lipoproteins in the subendothelial space causes a local overabundance of free cholesterol. Because cholesterol accumulation and deposition of cholesterol crystals (CCs) trigger a complex inflammatory response, we tested the efficacy of the cyclic oligosaccharide 2-hydroxypropyl-β-cyclodextrin (CD), a compound that increases cholesterol solubility in preventing and reversing atherosclerosis. We showed that CD treatment of murine atherosclerosis reduced atherosclerotic plaque size and CC load and promoted plaque regression even with a continued cholesterol-rich diet. Mechanistically, CD increased oxysterol production in both macrophages and human atherosclerotic plaques and promoted liver X receptor (LXR)-mediated transcriptional reprogramming to improve cholesterol efflux and exert anti-inflammatory effects. In vivo, this CD-mediated LXR agonism was required for the antiatherosclerotic and anti-inflammatory effects of CD as well as for augmented reverse cholesterol transport. Because CD treatment in humans is safe and CD beneficially affects key mechanisms of atherogenesis, it may therefore be used clinically to prevent or treat human atherosclerosis.

  12. Maintenance of age in human neurons generated by microRNA-based neuronal conversion of fibroblasts

    PubMed Central

    Huh, Christine J; Zhang, Bo; Victor, Matheus B; Dahiya, Sonika; Batista, Luis FZ; Horvath, Steve; Yoo, Andrew S

    2016-01-01

    Aging is a major risk factor in many forms of late-onset neurodegenerative disorders. The ability to recapitulate age-related characteristics of human neurons in culture will offer unprecedented opportunities to study the biological processes underlying neuronal aging. Here, we show that using a recently demonstrated microRNA-based cellular reprogramming approach, human fibroblasts from postnatal to near centenarian donors can be efficiently converted into neurons that maintain multiple age-associated signatures. Application of an epigenetic biomarker of aging (referred to as epigenetic clock) to DNA methylation data revealed that the epigenetic ages of fibroblasts were highly correlated with corresponding age estimates of reprogrammed neurons. Transcriptome and microRNA profiles reveal genes differentially expressed between young and old neurons. Further analyses of oxidative stress, DNA damage and telomere length exhibit the retention of age-associated cellular properties in converted neurons from corresponding fibroblasts. Our results collectively demonstrate the maintenance of age after neuronal conversion. DOI: http://dx.doi.org/10.7554/eLife.18648.001 PMID:27644593

  13. Reprogramming: A Preventive Strategy in Hypertension Focusing on the Kidney

    PubMed Central

    Tain, You-Lin; Joles, Jaap A.

    2015-01-01

    Adulthood hypertension can be programmed in response to a suboptimal environment in early life. However, developmental plasticity also implies that one can prevent hypertension in adult life by administrating appropriate compounds during early development. We have termed this reprogramming. While the risk of hypertension has been assessed in many mother-child cohorts of human developmental programming, interventions necessary to prove causation and provide a reprogramming strategy are lacking. Since the developing kidney is particularly vulnerable to environmental insults and blood pressure is determined by kidney function, renal programming is considered key in developmental programming of hypertension. Common pathways, whereby both genetic and acquired developmental programming converge into the same phenotype, have been recognized. For instance, the same reprogramming interventions aimed at shifting nitric oxide (NO)-reactive oxygen species (ROS) balance, such as perinatal citrulline or melatonin supplements, can be protective in both genetic and developmentally programmed hypertension. Furthermore, a significantly increased expression of gene Ephx2 (soluble epoxide hydrolase) was noted in both genetic and acquired animal models of hypertension. Since a suboptimal environment is often multifactorial, such common reprogramming pathways are a practical finding for translation to the clinic. This review provides an overview of potential clinical applications of reprogramming strategies to prevent programmed hypertension. We emphasize the kidney in the following areas: mechanistic insights from human studies and animal models to interpret programmed hypertension; identified risk factors of human programmed hypertension from mother-child cohorts; and the impact of reprogramming strategies on programmed hypertension from animal models. It is critical that the observed effects on developmental reprogramming in animal models are replicated in human studies. PMID

  14. Reprogramming cancer cells in endocrine-related tumors: open issues.

    PubMed

    Tafani, M; Perrone, G A; Pucci, B; Russo, A; Bizzarri, M; Mechanick, J I; Carpi, A; Russo, M A

    2014-01-01

    Reprogramming technologies have been developed to revert somatic differentiated cells into pluripotent stem cells that can be differentiated into different lineages potentially useful in stem cell therapy. Reprogramming methods have been progressively refined to increase their efficiency, to obtain a cell population suitable for differentiation, and to eliminate viral plasmid which could be responsible for many unwanted side-effects when used in personalized medicine. All these methods are aimed to introduce into the cell genes or mRNAs encoding a set of four transcription factors (OCT- 4, SOX-2, KLF-4 and c-MYC) or a set of three lincRNAs (large intragenic non-coding RNAs) acting downstream of the reprogramming transcription factors OCT-4, SOX-2 and NANOG. Translational clinical applications in human pathologies and in developmental, repair and cancer biology have been numerous. Cancer cells can be, at least in principle, reprogrammed into a normal phenotype. This is a recently raised issue, rapidly advancing in many human tumors, especially endocrine-related cancers, such as breast, prostate and ovarian ca. The present review aims to describe basic phenomena observed in reprogramming tumor cells and solid tumors and to discuss their meaning in human hormone-related cancers. We will also discuss the fact that some of the targeted transcription factors are "normally" activated in a number of physiological processes, such as morphogenesis, hypoxia and wound healing, suggesting an in vivo role of reprogramming for development and homeostasis. Finally, we will review concerns and warnings raised for in vivo reprogramming of human tumors and for the use of induced pluripotent stem cells (iPSCs) in human therapy.

  15. Reprogramming: A Preventive Strategy in Hypertension Focusing on the Kidney.

    PubMed

    Tain, You-Lin; Joles, Jaap A

    2015-12-25

    Adulthood hypertension can be programmed in response to a suboptimal environment in early life. However, developmental plasticity also implies that one can prevent hypertension in adult life by administrating appropriate compounds during early development. We have termed this reprogramming. While the risk of hypertension has been assessed in many mother-child cohorts of human developmental programming, interventions necessary to prove causation and provide a reprogramming strategy are lacking. Since the developing kidney is particularly vulnerable to environmental insults and blood pressure is determined by kidney function, renal programming is considered key in developmental programming of hypertension. Common pathways, whereby both genetic and acquired developmental programming converge into the same phenotype, have been recognized. For instance, the same reprogramming interventions aimed at shifting nitric oxide (NO)-reactive oxygen species (ROS) balance, such as perinatal citrulline or melatonin supplements, can be protective in both genetic and developmentally programmed hypertension. Furthermore, a significantly increased expression of gene Ephx2 (soluble epoxide hydrolase) was noted in both genetic and acquired animal models of hypertension. Since a suboptimal environment is often multifactorial, such common reprogramming pathways are a practical finding for translation to the clinic. This review provides an overview of potential clinical applications of reprogramming strategies to prevent programmed hypertension. We emphasize the kidney in the following areas: mechanistic insights from human studies and animal models to interpret programmed hypertension; identified risk factors of human programmed hypertension from mother-child cohorts; and the impact of reprogramming strategies on programmed hypertension from animal models. It is critical that the observed effects on developmental reprogramming in animal models are replicated in human studies.

  16. Binding, uptake, and release of nicotine by human gingival fibroblasts

    SciTech Connect

    Hanes, P.J.; Schuster, G.S.; Lubas, S. )

    1991-02-01

    Previous studies of the effects of nicotine on fibroblasts have reported an altered morphology and attachment of fibroblasts to substrates and disturbances in protein synthesis and secretion. This altered functional and attachment response may be associated with changes in the cell membrane resulting from binding of the nicotine, or to disturbances in cell metabolism as a result of high intracellular levels of nicotine. The purpose of the present study, therefore, was to (1) determine whether gingival fibroblasts bound nicotine and if any binding observed was specific or non-specific in nature; (2) determine whether gingival fibroblasts internalized nicotine, and if so, at what rate; (3) determine whether gingival fibroblasts also released nicotine back into the extracellular environment; and (4) if gingival fibroblasts release nicotine intact or as a metabolite. Cultures of gingival fibroblasts were prepared from gingival connective tissue biopsies. Binding was evaluated at 4{degree}C using a mixture of {sup 3}H-nicotine and unlabeled nicotine. Specific binding was calculated as the difference between {sup 3}H-nicotine bound in the presence and absence of unlabeled nicotine. The cells bound 1.44 (+/- 0.42) pmols/10(6) cells in the presence of unlabeled nicotine and 1.66 (+/- 0.55) pmols/10(6) cells in the absence of unlabeled nicotine. The difference was not significant. Uptake of nicotine was measured at 37{degree}C after treating cells with {sup 3}H-nicotine for time periods up to 4 hours. Uptake in pmols/10(6) cells was 4.90 (+/- 0.34) at 15 minutes, 8.30 (+/- 0.75) at 30 minutes, 12.28 (+/- 2.62) at 1 hour and 26.31 (+/- 1.15) at 4 hours.

  17. Netrin-1 regulates somatic cell reprogramming and pluripotency maintenance

    PubMed Central

    Ozmadenci, Duygu; Féraud, Olivier; Markossian, Suzy; Kress, Elsa; Ducarouge, Benjamin; Gibert, Benjamin; Ge, Jian; Durand, Isabelle; Gadot, Nicolas; Plateroti, Michela; Bennaceur-Griscelli, Annelise; Scoazec, Jean-Yves; Gil, Jesus; Deng, Hongkui; Bernet, Agnes; Mehlen, Patrick; Lavial, Fabrice

    2015-01-01

    The generation of induced pluripotent stem (iPS) cells holds great promise in regenerative medicine. The use of the transcription factors Oct4, Sox2, Klf4 and c-Myc for reprogramming is extensively documented, but comparatively little is known about soluble molecules promoting reprogramming. Here we identify the secreted cue Netrin-1 and its receptor DCC, described for their respective survival/death functions in normal and oncogenic contexts, as reprogramming modulators. In various somatic cells, we found that reprogramming is accompanied by a transient transcriptional repression of Netrin-1 mediated by an Mbd3/Mta1/Chd4-containing NuRD complex. Mechanistically, Netrin-1 imbalance induces apoptosis mediated by the receptor DCC in a p53-independent manner. Correction of the Netrin-1/DCC equilibrium constrains apoptosis and improves reprogramming efficiency. Our work also sheds light on Netrin-1's function in protecting embryonic stem cells from apoptosis mediated by its receptor UNC5b, and shows that the treatment with recombinant Netrin-1 improves the generation of mouse and human iPS cells. PMID:26154507

  18. Epigenetic reprogramming in mammalian species after SCNT-based cloning.

    PubMed

    Niemann, Heiner

    2016-07-01

    The birth of "Dolly," the first mammal cloned from an adult mammary epithelial cell, abolished the decades-old scientific dogma implying that a terminally differentiated cell cannot be reprogrammed into a pluripotent embryonic state. The most dramatic epigenetic reprogramming occurs in SCNT when the expression profile of a differentiated cell is abolished and a new embryo-specific expression profile, involving 10,000 to 12,000 genes, and thus, most genes of the entire genome is established, which drives embryonic and fetal development. The initial release from somatic cell epigenetic constraints is followed by establishment of post-zygotic expression patterns, X-chromosome inactivation, and adjustment of telomere length. Somatic cell nuclear transfer may be associated with a variety of pathologic changes of the fetal and placental phenotype in a proportion of cloned offspring, specifically in ruminants, that are thought to be caused by aberrant epigenetic reprogramming. Improvements in our understanding of this dramatic epigenetic reprogramming event will be instrumental in realizing the great potential of SCNT for basic research and for important agricultural and biomedical applications. Here, current knowledge on epigenetic reprogramming after use of SCNT in livestock is reviewed, with emphasis on gene-specific and global DNA methylation, imprinting, X-chromosome inactivation, and telomere length restoration in early development.

  19. The acetyllysine reader BRD3R promotes human nuclear reprogramming and regulates mitosis

    PubMed Central

    Shao, Zhicheng; Zhang, Ruowen; Khodadadi-Jamayran, Alireza; Chen, Bo; Crowley, Michael R.; Festok, Muhamad A.; Crossman, David K.; Townes, Tim M.; Hu, Kejin

    2016-01-01

    It is well known that both recipient cells and donor nuclei demonstrate a mitotic advantage as observed in the traditional reprogramming with somatic cell nuclear transfer (SCNT). However, it is not known whether a specific mitotic factor plays a critical role in reprogramming. Here we identify an isoform of human bromodomain-containing 3 (BRD3), BRD3R (BRD3 with Reprogramming activity), as a reprogramming factor. BRD3R positively regulates mitosis during reprogramming, upregulates a large set of mitotic genes at early stages of reprogramming, and associates with mitotic chromatin. Interestingly, a set of the mitotic genes upregulated by BRD3R constitutes a pluripotent molecular signature. The two BRD3 isoforms display differential binding to acetylated histones. Our results suggest a molecular interpretation for the mitotic advantage in reprogramming and show that mitosis may be a driving force of reprogramming. PMID:26947130

  20. Epigenetic regulation of B lymphocyte differentiation, transdifferentiation, and reprogramming.

    PubMed

    Barneda-Zahonero, Bruna; Roman-Gonzalez, Lidia; Collazo, Olga; Mahmoudi, Tokameh; Parra, Maribel

    2012-01-01

    B cell development is a multistep process that is tightly regulated at the transcriptional level. In recent years, investigators have shed light on the transcription factor networks involved in all the differentiation steps comprising B lymphopoiesis. The interplay between transcription factors and the epigenetic machinery involved in establishing the correct genomic landscape characteristic of each cellular state is beginning to be dissected. The participation of "epigenetic regulator-transcription factor" complexes is also crucial for directing cells during reprogramming into pluripotency or lineage conversion. In this context, greater knowledge of epigenetic regulation during B cell development, transdifferentiation, and reprogramming will enable us to understand better how epigenetics can control cell lineage commitment and identity. Herein, we review the current knowledge about the epigenetic events that contribute to B cell development and reprogramming.

  1. Cadherin-11 Induces Rheumatoid Arthritis Fibroblast-Like Synoviocytes to Form Lining Layers in Vitro

    PubMed Central

    Kiener, Hans P.; Lee, David M.; Agarwal, Sandeep K.; Brenner, Michael B.

    2006-01-01

    The synovial lining of diarthrodial joints is composed of a condensed network of synoviocytes that form an intact layer via cell-to-cell contacts with significant intercellular matrix spaces. However, the molecular basis for synovial lining formation and its structural integrity has not been previously defined. In this study, using a three-dimensional fibroblast-like synoviocyte in vitro organ culture system, we provide evidence that cadherin-11 expressed in fibroblast-like synoviocytes plays a determining role in establishing the synovial lining layer. Fibroblast-like synoviocytes that were grown in three-dimensional matrices demonstrated formation of a lining structure at the interface between the matrix and the fluid phase. Treatment of fibroblast-like synoviocyte organ cultures with a cadherin-11-Fc fusion protein efficiently abrogated lining layer organization. Moreover, because E-cadherin-expressing fibroblasts failed to organize a lining layer structure at the tissue boundary, this effect appears to be a distinct characteristic of fibroblasts expressing cadherin-11. We found that cadherin-11 mediated fibroblast-like synoviocyte cell-to-cell adhesion via formation of adherens junctions that were linked to and remodeled the actin cytoskeleton. Together, these studies implicate cadherin-11 in synovial tissue and lining layer formation and provide an in vitro system to model fibroblast-like synoviocyte behavior and function in organizing the synovial tissue. PMID:16651616

  2. MyoD reprogramming requires Six1 and Six4 homeoproteins: genome-wide cis-regulatory module analysis

    PubMed Central

    Santolini, Marc; Sakakibara, Iori; Gauthier, Morgane; Ribas-Aulinas, Francesc; Takahashi, Hirotaka; Sawasaki, Tatsuya; Mouly, Vincent; Concordet, Jean-Paul; Defossez, Pierre-Antoine; Hakim, Vincent; Maire, Pascal

    2016-01-01

    Myogenic regulatory factors of the MyoD family have the ability to reprogram differentiated cells toward a myogenic fate. In this study, we demonstrate that Six1 or Six4 are required for the reprogramming by MyoD of mouse embryonic fibroblasts (MEFs). Using microarray experiments, we found 761 genes under the control of both Six and MyoD. Using MyoD ChIPseq data and a genome-wide search for Six1/4 MEF3 binding sites, we found significant co-localization of binding sites for MyoD and Six proteins on over a thousand mouse genomic DNA regions. The combination of both datasets yielded 82 genes which are synergistically activated by Six and MyoD, with 96 associated MyoD+MEF3 putative cis-regulatory modules (CRMs). Fourteen out of 19 of the CRMs that we tested demonstrated in Luciferase assays a synergistic action also observed for their cognate gene. We searched putative binding sites on these CRMs using available databases and de novo search of conserved motifs and demonstrated that the Six/MyoD synergistic activation takes place in a feedforward way. It involves the recruitment of these two families of transcription factors to their targets, together with partner transcription factors, encoded by genes that are themselves activated by Six and MyoD, including Mef2, Pbx-Meis and EBF. PMID:27302134

  3. Cellular reprogramming for understanding and treating human disease

    PubMed Central

    Kanherkar, Riya R.; Bhatia-Dey, Naina; Makarev, Evgeny; Csoka, Antonei B.

    2014-01-01

    In the last two decades we have witnessed a paradigm shift in our understanding of cells so radical that it has rewritten the rules of biology. The study of cellular reprogramming has gone from little more than a hypothesis, to applied bioengineering, with the creation of a variety of important cell types. By way of metaphor, we can compare the discovery of reprogramming with the archeological discovery of the Rosetta stone. This stone slab made possible the initial decipherment of Egyptian hieroglyphics because it allowed us to see this language in a way that was previously impossible. We propose that cellular reprogramming will have an equally profound impact on understanding and curing human disease, because it allows us to perceive and study molecular biological processes such as differentiation, epigenetics, and chromatin in ways that were likewise previously impossible. Stem cells could be called “cellular Rosetta stones” because they allow also us to perceive the connections between development, disease, cancer, aging, and regeneration in novel ways. Here we present a comprehensive historical review of stem cells and cellular reprogramming, and illustrate the developing synergy between many previously unconnected fields. We show how stem cells can be used to create in vitro models of human disease and provide examples of how reprogramming is being used to study and treat such diverse diseases as cancer, aging, and accelerated aging syndromes, infectious diseases such as AIDS, and epigenetic diseases such as polycystic ovary syndrome. While the technology of reprogramming is being developed and refined there have also been significant ongoing developments in other complementary technologies such as gene editing, progenitor cell production, and tissue engineering. These technologies are the foundations of what is becoming a fully-functional field of regenerative medicine and are converging to a point that will allow us to treat almost any disease. PMID

  4. Differential Reprogramming Based on Constructive Interference for Wireless Sensor Network

    NASA Astrophysics Data System (ADS)

    Hu, Bing; Sun, Zhixin

    2016-09-01

    To improve the performance of reprogramming in wireless sensor network, we present a novel reprogramming structure and constructive interference-based dissemination protocol (CIDP) to transmit the patch through out the network fast and reliability. CIDP disseminates the patch, which is divided into several packets, to the network exploiting constructive interference. We evaluate our implementation of CIDP using simulation under different number of nodes. Our results show that CIDP disseminates the patch less than 4 milliseconds. In general, the probability of a node receives the complete patch as high as 99.99%.

  5. Analysis of nuclear reprogramming following nuclear transfer to Xenopus oocyte.

    PubMed

    Jullien, Jerome

    2015-01-01

    Germinal vesicle of stage V-VI Xenopus Laevis oocytes (at the prophase I stage of meiosis) can be used to transplant mammalian nuclei. In this type of interspecies nuclear transfer no cell division occurs and no new cell types are generated. However, the transplanted nuclei undergo extensive transcriptional reprogramming. Here, it is first explained how to carry out transplantation of multiple mammalian cell nuclei to Xenopus oocytes. It is then described how to perform RT-qPCR, Western Blot, Chromatin Immunoprecipitation, and live imaging analysis to monitor transcriptional reprogramming of the nuclei transplanted to oocytes.

  6. Dedifferentiation, transdifferentiation and reprogramming: three routes to regeneration.

    PubMed

    Jopling, Chris; Boue, Stephanie; Izpisua Belmonte, Juan Carlos

    2011-02-01

    The ultimate goal of regenerative medicine is to replace lost or damaged cells. This can potentially be accomplished using the processes of dedifferentiation, transdifferentiation or reprogramming. Recent advances have shown that the addition of a group of genes can not only restore pluripotency in a fully differentiated cell state (reprogramming) but can also induce the cell to proliferate (dedifferentiation) or even switch to another cell type (transdifferentiation). Current research aims to understand how these processes work and to eventually harness them for use in regenerative medicine.

  7. Chromatin modification and epigenetic reprogramming in mammalian development.

    PubMed

    Li, En

    2002-09-01

    The developmental programme of embryogenesis is controlled by both genetic and epigenetic mechanisms. An emerging theme from recent studies is that the regulation of higher-order chromatin structures by DNA methylation and histone modification is crucial for genome reprogramming during early embryogenesis and gametogenesis, and for tissue-specific gene expression and global gene silencing. Disruptions to chromatin modification can lead to the dysregulation of developmental processes, such as X-chromosome inactivation and genomic imprinting, and to various diseases. Understanding the process of epigenetic reprogramming in development is important for studies of cloning and the clinical application of stem-cell therapy.

  8. Synthesis of polyester by means of genetic code reprogramming.

    PubMed

    Ohta, Atsushi; Murakami, Hiroshi; Higashimura, Eri; Suga, Hiroaki

    2007-12-01

    Here we report the ribosomal polymerization of alpha-hydroxy acids by means of genetic code reprogramming. The flexizyme system, a ribozyme-based tRNA acylation tool, was used to re-assign individual codons to seven types of alpha-hydroxy acids, and then polyesters were synthesized under controls of the reprogrammed genetic code using a reconstituted cell-free translation system. The sequence and length of the polyester segments were specified by the mRNA template, indicating that high-fidelity ribosome expression of polyesters was possible. This work opens a door for the mRNA-directed synthesis of backbone-altered biopolymers.

  9. Evaluating cell reprogramming, differentiation and conversion technologies in neuroscience.

    PubMed

    Mertens, Jerome; Marchetto, Maria C; Bardy, Cedric; Gage, Fred H

    2016-07-01

    The scarcity of live human brain cells for experimental access has for a long time limited our ability to study complex human neurological disorders and elucidate basic neuroscientific mechanisms. A decade ago, the development of methods to reprogramme somatic human cells into induced pluripotent stem cells enabled the in vitro generation of a wide range of neural cells from virtually any human individual. The growth of methods to generate more robust and defined neural cell types through reprogramming and direct conversion into induced neurons has led to the establishment of various human reprogramming-based neural disease models.

  10. The mitochondrial H(+)-ATP synthase and the lipogenic switch: new core components of metabolic reprogramming in induced pluripotent stem (iPS) cells.

    PubMed

    Vazquez-Martin, Alejandro; Corominas-Faja, Bruna; Cufi, Sílvia; Vellon, Luciano; Oliveras-Ferraros, Cristina; Menendez, Octavio J; Joven, Jorge; Lupu, Ruth; Menendez, Javier A

    2013-01-15

    Induced pluripotent stem (iPS) cells share some basic properties, such as self-renewal and pluripotency, with cancer cells, and they also appear to share several metabolic alterations that are commonly observed in human tumors. The cancer cells' glycolytic phenotype, first reported by Otto Warburg, is necessary for the optimal routing of somatic cells to pluripotency. However, how iPS cells establish a Warburg-like metabolic phenotype and whether the metabolic pathways that support the bioenergetics of iPS cells are produced by the same mechanisms that are selected during the tumorigenic process remain largely unexplored. We recently investigated whether the reprogramming-competent metabotype of iPS cells involves changes in the activation/expression status of the H(+)-ATPase, which is a core component of mitochondrial oxidative phosphorylation that is repressed at both the activity and protein levels in human carcinomas, and of the lipogenic switch, which refers to a marked overexpression and hyperactivity of the acetyl-CoA carboxylase (ACACA) and fatty acid synthase (FASN) lipogenic enzymes that has been observed in nearly all examined cancer types. A comparison of a starting population of mouse embryonic fibroblasts and their iPS cell progeny revealed that somatic cell reprogramming involves a significant increase in the expression of ATPase inhibitor factor 1 (IF1), accompanied by extremely low expression levels of the catalytic β-F1-ATPase subunit. The pharmacological inhibition of ACACA and FASN activities markedly decreases reprogramming efficiency, and ACACA and FASN expression are notably upregulated in iPS cells. Importantly, iPS cells exhibited a significant intracellular accumulation of neutral lipid bodies; however, these bodies may be a reflection of intense lysosomal/autophagocytic activity rather than bona fide lipid droplet formation in iPS cells, as they were largely unresponsive to pharmacological modulation of PPARgamma and FASN activities. The

  11. Properties of sulfatases in cultured skin fibroblasts of multiple sulfatase deficient patients.

    PubMed

    Yutaka, T; Okada, S; Kato, T; Inui, K; Yabuuchi, H

    1981-10-01

    Various sulfatase activities were assayed in cultured skin fibroblasts from patients with multiple sulfatase deficiency (MSD). MSD cell lines displayed deficiencies of arylsulfatase A and iduronate sulfatase, but activities of arylsulfatase B, N-acetylgalactosamine 6-sulfate sulfatase and N-acetylglucosamine 6-sulfate sulfatase were within normal ranges, but not consistently. Arylsulfatase A, minor anionic arylsulfatase and N-acetylgalactosamine 6-sulfate sulfatase in MSD cell lines had similar Km, pH optima, inhibitory or activator sensitivity to that of normal skin fibroblasts. Arylsulfatase B in MSD cell lines also had properties similar to that of normal skin fibroblasts, except an abnormal heat stability. From our results, we conclude that properties of arylsulfatase A, minor anionic arylsulfatase and N-acetylgalactosamine 6-sulfate sulfatase in MSD fibroblasts were intact. On the other hand, arylsulfatase B in MSD might be a functionally abnormal enzyme.

  12. 45 CFR 1606.13 - Interim and termination funding; reprogramming.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Interim and termination funding; reprogramming. 1606.13 Section 1606.13 Public Welfare Regulations Relating to Public Welfare (Continued) LEGAL SERVICES CORPORATION TERMINATION AND DEBARMENT PROCEDURES; RECOMPETITION § 1606.13 Interim and...

  13. Renal stem cell reprogramming: Prospects in regenerative medicine

    PubMed Central

    Morales, Elvin E; Wingert, Rebecca A

    2014-01-01

    Stem cell therapy is a promising future enterprise for renal replacement in patients with acute and chronic kidney disease, conditions which affect millions worldwide and currently require patients to undergo lifelong medical treatments through dialysis and/or organ transplant. Reprogramming differentiated renal cells harvested from the patient back into a pluripotent state would decrease the risk of tissue rejection and provide a virtually unlimited supply of cells for regenerative medicine treatments, making it an exciting area of current research in nephrology. Among the major hurdles that need to be overcome before stem cell therapy for the kidney can be applied in a clinical setting are ensuring the fidelity and relative safety of the reprogrammed cells, as well as achieving feasible efficiency in the reprogramming processes that are utilized. Further, improved knowledge about the genetic control of renal lineage development is vital to identifying predictable and efficient reprogramming approaches, such as the expression of key modulators or the regulation of gene activity through small molecule mimetics. Here, we discuss several recent advances in induced pluripotent stem cell technologies. We also explore strategies that have been successful in renal progenitor generation, and explore what these methods might mean for the development of cell-based regenerative therapies for kidney disease. PMID:25258667

  14. Cellular Reprogramming Using Defined Factors and MicroRNAs

    PubMed Central

    Eguchi, Takanori; Kuboki, Takuo

    2016-01-01

    Development of human bodies, organs, and tissues contains numerous steps of cellular differentiation including an initial zygote, embryonic stem (ES) cells, three germ layers, and multiple expertized lineages of cells. Induced pluripotent stem (iPS) cells have been recently developed using defined reprogramming factors such as Nanog, Klf5, Oct3/4 (Pou5f1), Sox2, and Myc. This outstanding innovation is largely changing life science and medicine. Methods of direct reprogramming of cells into myocytes, neurons, chondrocytes, and osteoblasts have been further developed using modified combination of factors such as N-myc, L-myc, Sox9, and microRNAs in defined cell/tissue culture conditions. Mesenchymal stem cells (MSCs) and dental pulp stem cells (DPSCs) are also emerging multipotent stem cells with particular microRNA expression signatures. It was shown that miRNA-720 had a role in cellular reprogramming through targeting the pluripotency factor Nanog and induction of DNA methyltransferases (DNMTs). This review reports histories, topics, and idea of cellular reprogramming. PMID:27382371

  15. Molecular Imaging of Metabolic Reprograming in Mutant IDH Cells.

    PubMed

    Viswanath, Pavithra; Chaumeil, Myriam M; Ronen, Sabrina M

    2016-01-01

    Mutations in the metabolic enzyme isocitrate dehydrogenase (IDH) have recently been identified as drivers in the development of several tumor types. Most notably, cytosolic IDH1 is mutated in 70-90% of low-grade gliomas and upgraded glioblastomas, and mitochondrial IDH2 is mutated in ~20% of acute myeloid leukemia cases. Wild-type IDH catalyzes the interconversion of isocitrate to α-ketoglutarate (α-KG). Mutations in the enzyme lead to loss of wild-type enzymatic activity and a neomorphic activity that converts α-KG to 2-hydroxyglutarate (2-HG). In turn, 2-HG, which has been termed an "oncometabolite," inhibits key α-KG-dependent enzymes, resulting in alterations of the cellular epigenetic profile and, subsequently, inhibition of differentiation and initiation of tumorigenesis. In addition, it is now clear that the IDH mutation also induces a broad metabolic reprograming that extends beyond 2-HG production, and this reprograming often differs from what has been previously reported in other cancer types. In this review, we will discuss in detail what is known to date about the metabolic reprograming of mutant IDH cells, and how this reprograming has been investigated using molecular metabolic imaging. We will describe how metabolic imaging has helped shed light on the basic biology of mutant IDH cells, and how this information can be leveraged to identify new therapeutic targets and to develop new clinically translatable imaging methods to detect and monitor mutant IDH tumors in vivo.

  16. Movement Planning and Reprogramming in Individuals with Autism

    ERIC Educational Resources Information Center

    Nazarali, Natasha; Glazebrook, Cheryl M.; Elliott, Digby

    2009-01-01

    Two experiments explored how individuals with and without autism plan and reprogram movements. Participants were given partial or complete information regarding the location of the upcoming manual movement. In Experiment 1, direct information specified the hand or direction of the upcoming movement. These results replicated previous reports that…

  17. Nuclear reprogramming of cloned embryos produced in vitro.

    PubMed

    Han, Y M; Kang, Y K; Koo, D B; Lee, K K

    2003-01-01

    Despite the fact that cloned animals derived from somatic cells have been successfully generated in a variety of mammalian species, there are still many unsolved problems with current cloning technology. Somatic cell nuclear transfer has shown several developmental aberrancies, including a high rate of abortion during early gestation and increased perinatal death. One cause of these developmental failures of cloned embryos may reside in the epigenetic reprogramming of somatic donor genome. In mammals, DNA methylation is an essential process in the regulation of transcription during embryonic development and is generally associated with gene silencing. A genome-wide demethylation may be a prerequisite for the formation of pluripotent stem cells that are important for later development. We analyzed methylation patterns in cloned bovine embryos to monitor the epigenetic reprogramming process of donor genomic DNA. Aberrant methylation profiles of cloned bovine embryos were observed in various genomic regions, except in single-copy gene sequences. The overall genomic methylation status of cloned embryos was quite different from that of normal embryos produced in vitro or in vivo. These results suggest that the developmental failures of cloned embryos may be due to incomplete epigenetic reprogramming of donor genomic DNA. We expect that advances in understanding the molecular events for reprogramming of donor genome will contribute to clarify the developmental defects of cloned embryos.

  18. Generation of LIF-independent induced pluripotent stem cells from canine fetal fibroblasts.

    PubMed

    Gonçalves, N J N; Bressan, F F; Roballo, K C S; Meirelles, F V; Xavier, P L P; Fukumasu, H; Williams, C; Breen, M; Koh, S; Sper, R; Piedrahita, J; Ambrósio, C E

    2017-04-01

    Takahashi and Yamanaka established the first technique in which transcription factors related to pluripotency are incorporated into the genome of somatic cells to enable reprogramming of these cells. The expression of these transcription factors enables a differentiated somatic cell to reverse its phenotype to an embryonic state, generating induced pluripotent stem cells (iPSCs). iPSCs from canine fetal fibroblasts were produced through lentiviral polycistronic human and mouse vectors (hOSKM/mOSKM), aiming to obtain pluripotent stem cells with similar features to embryonic stem cells (ESC) in this animal model. The cell lines obtained in this study were independent of LIF or any other supplemental inhibitors, resistant to enzymatic procedure (TrypLE Express Enzyme), and dependent on bFGF. Clonal lines were obtained from slightly different protocols with maximum reprogramming efficiency of 0.001%. All colonies were positive for alkaline phosphatase, embryoid body formation, and spontaneous differentiation and expressed high levels of endogenous OCT4 and SOX2. Canine iPSCs developed tumors at 120 days post-injection in vivo. Preliminary chromosomal evaluations were performed by FISH hybridization, revealing no chromosomal abnormality. To the best of our knowledge, this report is the first to describe the ability to reprogram canine somatic cells via lentiviral vectors without supplementation and with resistance to enzymatic action, thereby demonstrating the pluripotency of these cell lines.

  19. The developmental potential of iPSCs is greatly influenced by reprogramming factor selection.

    PubMed

    Buganim, Yosef; Markoulaki, Styliani; van Wietmarschen, Niek; Hoke, Heather; Wu, Tao; Ganz, Kibibi; Akhtar-Zaidi, Batool; He, Yupeng; Abraham, Brian J; Porubsky, David; Kulenkampff, Elisabeth; Faddah, Dina A; Shi, Linyu; Gao, Qing; Sarkar, Sovan; Cohen, Malkiel; Goldmann, Johanna; Nery, Joseph R; Schultz, Matthew D; Ecker, Joseph R; Xiao, Andrew; Young, Richard A; Lansdorp, Peter M; Jaenisch, Rudolf

    2014-09-04

    Induced pluripotent stem cells (iPSCs) are commonly generated by transduction of Oct4, Sox2, Klf4, and Myc (OSKM) into cells. Although iPSCs are pluripotent, they frequently exhibit high variation in terms of quality, as measured in mice by chimera contribution and tetraploid complementation. Reliably high-quality iPSCs will be needed for future therapeutic applications. Here, we show that one major determinant of iPSC quality is the combination of reprogramming factors used. Based on tetraploid complementation, we found that ectopic expression of Sall4, Nanog, Esrrb, and Lin28 (SNEL) in mouse embryonic fibroblasts (MEFs) generated high-quality iPSCs more efficiently than other combinations of factors including OSKM. Although differentially methylated regions, transcript number of master regulators, establishment of specific superenhancers, and global aneuploidy were comparable between high- and low-quality lines, aberrant gene expression, trisomy of chromosome 8, and abnormal H2A.X deposition were distinguishing features that could potentially also be applicable to human.

  20. The reprogramming of tumor stroma by HSF1 is a potent enabler of malignancy

    PubMed Central

    Scherz-Shouval, Ruth; Santagata, Sandro; Mendillo, Marc L.; Sholl, Lynette M.; Ben-Aharon, Irit; Beck, Andrew H.; Dias-Santagata, Dora; Koeva, Martina; Stemmer, Salomon M.; Whitesell, Luke; Lindquist, Susan

    2014-01-01

    Summary Stromal cells within the tumor microenvironment are essential for tumor progression and metastasis. Surprisingly little is known about the factors that drive the transcriptional reprogramming of stromal cells within tumors. We report that the transcriptional regulator Heat-Shock Factor 1 (HSF1) is frequently activated in cancer-associated fibroblasts (CAFs), where it is a potent enabler of malignancy. HSF1 drives a transcriptional program in CAFs that complements, yet is completely different from, the program it drives in adjacent cancer cells. This CAF program is uniquely structured to support the malignant potential of cancer cells in a non-cell-autonomous way. Two central stromal signaling molecules—TGFβ and stromal-derived factor 1 (SDF1) – play a critical role. In early stage breast and lung cancer, high stromal HSF1 activation is strongly associated with poor patient outcome. Thus, tumors co-opt the ancient survival functions of HSF1 to orchestrate malignancy in both cell-autonomous and non-cell-autonomous ways, with far-reaching therapeutic implications. PMID:25083868

  1. Combined positive effect of oocyte extracts and brilliant cresyl blue stained recipient cytoplasts on epigenetic reprogramming and gene expression in buffalo nuclear transfer embryos.

    PubMed

    Sadeesh, E M; Fozia, Shah; Meena, Kataria

    2017-04-01

    This study examined the effects of buffalo oocyte extracts (BOE) on donor cells reprogramming and molecular characterisation of oocytes screened via brilliant cresyl blue (BCB) staining and comparison of gene expression profiles of developmentally important genes in blastocysts from IVF and cloned derived from BOE treated donor cells with BCB selected recipient cytoplasts. Relative abundance (RA) of OCT4 and NANOG was increased (P < 0.05) and HDAC-1, DNMT-1, and DNMT-3A decreased (P < 0.05) in extract treated cells (ETCs). This ETCs dedifferentiated into neuron-like lineage under appropriate induction condition. The RA of NASP, EEF1A1, DNMT1, ODC1 and RPS27A was increased (P < 0.05) in BCB+ oocytes, whereas ATP5A1 and S100A10 increased (P < 0.05) in BCB- oocytes. Total cell number and RA of OCT4, NANOG, SOX2, DNMT1, IGF2, IGF2R, MNSOD, GLUT1, BAX and BCL2 in cloned blastocysts derived from BCB+ oocytes with ETC more closely followed that of IVF counterparts compared to BCB+ oocytes with extract untreated cell and BCB- oocytes with ETC derived blastocysts. In conclusion, BOE influenced epigenetic reprogramming of buffalo fibroblasts making them suitable donors for nuclear transfer (NT). BCB staining can be effectively used for selection of developmentally competent oocytes for NT. The combined effects of epigenetic reprogramming of donor nuclei by BOE and higher nuclear reprogramming capacity of BCB+ oocytes improve developmentally important gene expression in cloned blastocysts. Whether these improvements have long-term effects on buffalo calves born following embryo transfer remains unknown.

  2. Isolation of the pericellular matrix of human fibroblast cultures

    PubMed Central

    1979-01-01

    The pericellular matrix of human fibroblast cultures was isolated, using sequential extraction with sodium deoxycholate and hypotonic buffer in the presence of protease inhibitor. The matrix attached to the growth substratum had a "sackcloth-like" structure as seen by phase contrast, immunofluorescence, and scanning electron microscopy, and it had a vaguely filamentous ultrastructure similar to that seen in intact cell layers. The matrix consisted of hyaluronic acid and heparan sulfate as the major glycosaminoglycan components and fibronectin and procollagen as major polypeptides as shown by metabolic labeling, gel electrophoresis, immunofluorescence, and collagenase digestion. This pericellular matrix can be regarded as an in vitro equivalent of the loose connective tissue matrix. PMID:383722

  3. Concise review: harmonies played by microRNAs in cell fate reprogramming.

    PubMed

    Moradi, Sharif; Asgari, Sassan; Baharvand, Hossein

    2014-01-01

    It is now well-established that somatic cells can be reprogrammed to alternative cell fates by ectopic coexpression of defined factors. Reprogramming technology has uncovered a huge plasticity besides gene regulatory networks (GRNs) of differentiated cell states. MicroRNAs (miRNAs), which are an integral part of GRNs, have recently emerged as a powerful reprogramming toolbox. They regulate numerous genes, thereby modulating virtually all cellular processes, including somatic cell reprogramming. Not only can miRNAs provide novel opportunities for interrogating mechanisms of induced pluripotency and direct lineage reprogramming but they also offer hope for the efficient creation of safe cell sources for regenerative medicine. In reviewing landmark roles of miRNAs in cell reprogramming, we offer suggestions for evolution of the reprogramming field.

  4. Reprogramming bladder cancer cells for studying cancer initiation and progression.

    PubMed

    Iskender, Banu; Izgi, Kenan; Canatan, Halit

    2016-10-01

    The induced pluripotent stem cell (iPSC) technology is the forced expression of specific transcription factors in somatic cells resulting in transformation into self-renewing, pluripotent cells which possess the ability to differentiate into any type of cells in the human body. While malignant cells could also be reprogrammed into iPSC-like cells with lower efficiency due to the genetic and epigenetic barriers in cancer cells, only a limited number of cancer cell types could be successfully reprogrammed until today. In the present study, we aimed at reprogramming two bladder cancer cell lines HTB-9 and T24 using a non-integrating Sendai virus (SeV) system. We have generated six sub-clones using distinct combinations of four factors-OCT4, SOX2, KLF4 and c-MYC-in two bladder cancer cell lines. Only a single sub-clone, T24 transduced with 4Fs, gave rise to iPSC-like cells. Bladder cancer cell-derived T24 4F cells represent unique features of pluripotent cells such as epithelial-like morphology, colony-forming ability, expression of pluripotency-associated markers and bearing the ability to differentiate in vitro. This is the first study focusing on the reprogramming susceptibility of two different bladder cancer cell lines to nuclear reprogramming. Further molecular characterisation of T24 4F cells could provide a better insight for biomarker research in bladder carcinogenesis and could offer a valuable tool for the development of novel therapeutic approaches in bladder carcinoma.

  5. Developmental Programming of Adult Disease: Reprogramming by Melatonin?

    PubMed

    Tain, You-Lin; Huang, Li-Tung; Hsu, Chien-Ning

    2017-02-16

    Adult-onset chronic non-communicable diseases (NCDs) can originate from early life through so-called the "developmental origins of health and disease" (DOHaD) or "developmental programming". The DOHaD concept offers the "reprogramming" strategy to shift the treatment from adulthood to early life, before clinical disease is apparent. Melatonin, an endogenous indoleamine produced by the pineal gland, has pleiotropic bioactivities those are beneficial in a variety of human diseases. Emerging evidence support that melatonin is closely inter-related to other proposed mechanisms contributing to the developmental programming of a variety of chronic NCDs. Recent animal studies have begun to unravel the multifunctional roles of melatonin in many experimental models of developmental programming. Even though some progress has been made in research on melatonin as a reprogramming strategy to prevent DOHaD-related NCDs, future human studies should aim at filling the translational gap between animal models and clinical trials. Here, we review several key themes on the reprogramming effects of melatonin in DOHaD research. We have particularly focused on the following areas: mechanisms of developmental programming; the interrelationship between melatonin and mechanisms underlying developmental programming; pathophysiological roles of melatonin in pregnancy and fetal development; and insight provided by animal models to support melatonin as a reprogramming therapy. Rates of NCDs are increasing faster than anticipated all over the world. Hence, there is an urgent need to understand reprogramming mechanisms of melatonin and to translate experimental research into clinical practice for halting a growing list of DOHaD-related NCDs.

  6. Temporal alterations in cardiac fibroblast function following induction of pressure overload

    PubMed Central

    Stewart, James A.; Massey, Erin P.; Fix, Charity; Zhu, Jinyu; Goldsmith, Edie C.

    2014-01-01

    Increases in cardiovascular load (pressure overload) are known to elicit ventricular remodeling including cardiomyocyte hypertrophy and interstitial fibrosis. While numerous studies have focused on the mechanisms of myocyte hypertrophy, comparatively little is known regarding the response of the interstitial fibroblasts to increased cardiovascular load. Fibroblasts are the most numerous cell type in the mammalian myocardium and have long been recognized as producing the majority of the myocardial extracellular matrix. It is only now becoming appreciated that other aspects of fibroblast behavior are important to overall cardiac function. The present studies were performed to examine the temporal alterations in fibroblast activity in response to increased cardiovascular load. Rat myocardial fibroblasts were isolated at specific time-points (3, 7, 14, and 28 days) after induction of pressure overload by abdominal aortic constriction. Bioassays were performed to measure specific parameters of fibroblast function including remodeling and contraction of 3-dimensional collagen gels, migration, and proliferation. In addition, the expression of extracellular matrix receptors of the integrin family was examined. Myocardial hypertrophy and fibrosis were evident within 7 days after constriction of the abdominal aorta. Collagen gel contraction, migration, and proliferation were enhanced in fibroblasts from pressure-overloaded animals compared to fibroblasts from sham animals. Differences in fibroblast function and protein expression were evident within 7 days of aortic constriction, concurrent with the onset of hypertrophy and fibrosis of the intact myocardium. These data provide further support for the idea that rapid and dynamic changes in fibroblast phenotype accompany and contribute to the progression of cardiovascular disease. PMID:20217135

  7. Autism Spectrum Disorder and intact executive functioning.

    PubMed

    Ferrara, R; Ansermet, F; Massoni, F; Petrone, L; Onofri, E; Ricci, P; Archer, T; Ricci, S

    2016-01-01

    Earliest notions concerning autism (Autism Spectrum Disorders, ASD) describe the disturbance in executive functioning. Despite altered definition, executive functioning, expressed as higher cognitive skills required complex behaviors linked to the prefrontal cortex, are defective in autism. Specific difficulties in children presenting autism or verbal disabilities at executive functioning levels have been identified. Nevertheless, the developmental deficit of executive functioning in autism is highly diversified with huge individual variation and may even be absent. The aim of the present study to examine the current standing of intact executive functioning intact in ASD.

  8. Fibroblast cell line establishment, cryopreservation and interspecies embryos reconstruction in red panda ( Ailurus fulgens).

    PubMed

    Tao, Yong; Liu, Jianming; Zhang, Yunhai; Zhang, Meiling; Fang, Junshun; Han, Wei; Zhang, Zhizhong; Liu, Ya; Ding, Jianping; Zhang, Xiaorong

    2009-05-01

    In evolution, the red panda (Ailurus fulgens) plays a pivotal role in the higher level phylogeny of arctoides carnivore mammals. The red panda inhabits certain Asian countries only and its numbers are decreasing. Therefore, the development of feasible ways to preserve this species is necessary. Genetic resource cryopreservation and somatic cell nuclear transfer (SCNT) have been used extensively to rescue this endangered species. The present study describes the establishment, for the first time, of a red panda ear fibroblast cell line, which was then cryopreserved, thawed and cultured. Through micromanipulation, interspecies embryos were reconstructed using the cryopreserved-thawed fibroblasts of the red panda as the donor and rabbit oocytes as recipients. A total of 194 enucleated rabbit oocytes were reconstructed with red panda ear fibroblasts; enucleated oocytes were activated without fusion as the control. The results show that the fibroblast cell line was established successfully by tissue culture and then cryopreserved in liquid nitrogen. Supplementation with 20% fetal bovine serum and 8% dimethyl sulphoxide in basic medium facilitated the cryopreservation. The interspecies embryos were successfully reconstructed. The cleavage, morulae and blastocyst rates after in vitro culture were 71, 47 and 23% (31/194), respectively. This study indicated that a somatic cell line could be established and cryopreserved from red panda and that rabbit cytoplast supports mitotic cleavage of the red panda karyoplasts and is capable of reprogramming the nucleus to achieve blastocysts.

  9. Direct conversion of human fibroblasts into functional osteoblasts by defined factors.

    PubMed

    Yamamoto, Kenta; Kishida, Tsunao; Sato, Yoshiki; Nishioka, Keisuke; Ejima, Akika; Fujiwara, Hiroyoshi; Kubo, Toshikazu; Yamamoto, Toshiro; Kanamura, Narisato; Mazda, Osam

    2015-05-12

    Osteoblasts produce calcified bone matrix and contribute to bone formation and remodeling. In this study, we established a procedure to directly convert human fibroblasts into osteoblasts by transducing some defined factors and culturing in osteogenic medium. Osteoblast-specific transcription factors, Runt-related transcription factor 2 (Runx2), and Osterix, in combination with Octamer-binding transcription factor 3/4 (Oct4) and L-Myc (RXOL) transduction, converted ∼ 80% of the fibroblasts into osteocalcin-producing cells. The directly converted osteoblasts (dOBs) induced by RXOL displayed a similar gene expression profile as normal human osteoblasts and contributed to bone repair after transplantation into immunodeficient mice at artificial bone defect lesions. The dOBs expressed endogenous Runx2 and Osterix, and did not require continuous expression of the exogenous genes to maintain their phenotype. Another combination, Oct4 plus L-Myc (OL), also induced fibroblasts to produce bone matrix, but the OL-transduced cells did not express Osterix and exhibited a more distant gene expression profile to osteoblasts compared with RXOL-transduced cells. These findings strongly suggest successful direct reprogramming of fibroblasts into functional osteoblasts by RXOL, a technology that may provide bone regeneration therapy against bone disorders.

  10. Reprogramming cancer cells: a novel approach for cancer therapy or a tool for disease-modeling?

    PubMed

    Yilmazer, Açelya; de Lázaro, Irene; Taheri, Hadiseh

    2015-12-01

    Chromatin dynamics have been the major focus of many physiological and pathological processes over the past 20 years. Epigenetic mechanisms have been shown to be reshaped during both cellular reprogramming and tumorigenesis. For this reason, cancer cell reprogramming can provide a powerful tool to better understand both regenerative and cancer-fate processes, with a potential to develop novel therapeutic approaches. Recent studies showed that cancer cells can be reprogrammed to a pluripotent state by the overexpression of reprogramming transcription factors. Activation of transcription factors and modification of chromatin regulators may result in the remodeling of epigenetic status and refueling of tumorigenicity in these reprogrammed cancer cells. However, studies focusing on cancer cell reprogramming are contradictory; some studies reported increased tumor progression whereas others showed that cellular reprogramming has a treatment potential for cancer. In this review, first, the current knowledge on the epigenetic mechanisms involved during cancer development and cellular reprogramming will be presented. Later, different reports and key factors about pluripotency-based reprogramming of cancer cells will be reviewed in detail. New insights will be provided on cancer biology and therapy in the light of cellular reprogramming.

  11. Reprogramming DNA methylation in the mammalian life cycle: building and breaking epigenetic barriers.

    PubMed

    Seisenberger, Stefanie; Peat, Julian R; Hore, Timothy A; Santos, Fátima; Dean, Wendy; Reik, Wolf

    2013-01-05

    In mammalian development, epigenetic modifications, including DNA methylation patterns, play a crucial role in defining cell fate but also represent epigenetic barriers that restrict developmental potential. At two points in the life cycle, DNA methylation marks are reprogrammed on a global scale, concomitant with restoration of developmental potency. DNA methylation patterns are subsequently re-established with the commitment towards a distinct cell fate. This reprogramming of DNA methylation takes place firstly on fertilization in the zygote, and secondly in primordial germ cells (PGCs), which are the direct progenitors of sperm or oocyte. In each reprogramming window, a unique set of mechanisms regulates DNA methylation erasure and re-establishment. Recent advances have uncovered roles for the TET3 hydroxylase and passive demethylation, together with base excision repair (BER) and the elongator complex, in methylation erasure from the zygote. Deamination by AID, BER and passive demethylation have been implicated in reprogramming in PGCs, but the process in its entirety is still poorly understood. In this review, we discuss the dynamics of DNA methylation reprogramming in PGCs and the zygote, the mechanisms involved and the biological significance of these events. Advances in our understanding of such natural epigenetic reprogramming are beginning to aid enhancement of experimental reprogramming in which the role of potential mechanisms can be investigated in vitro. Conversely, insights into in vitro reprogramming techniques may aid our understanding of epigenetic reprogramming in the germline and supply important clues in reprogramming for therapies in regenerative medicine.

  12. DNA Replication Is an Integral Part of the Mouse Oocyte’s Reprogramming Machinery

    PubMed Central

    Wang, Bingyuan; Pfeiffer, Martin J.; Schwarzer, Caroline; Araúzo-Bravo, Marcos J.; Boiani, Michele

    2014-01-01

    Many of the structural and mechanistic requirements of oocyte-mediated nuclear reprogramming remain elusive. Previous accounts that transcriptional reprogramming of somatic nuclei in mouse zygotes may be complete in 24–36 hours, far more rapidly than in other reprogramming systems, raise the question of whether the mere exposure to the activated mouse ooplasm is sufficient to enact reprogramming in a nucleus. We therefore prevented DNA replication and cytokinesis, which ensue after nuclear transfer, in order to assess their requirement for transcriptional reprogramming of the key pluripotency genes Oct4 (Pou5f1) and Nanog in cloned mouse embryos. Using transcriptome and allele-specific analysis, we observed that hundreds of mRNAs, but not Oct4 and Nanog, became elevated in nucleus-transplanted oocytes without DNA replication. Progression through the first round of DNA replication was essential but not sufficient for transcriptional reprogramming of Oct4 and Nanog, whereas cytokinesis and thereby cell-cell interactions were dispensable for transcriptional reprogramming. Responses similar to clones also were observed in embryos produced by fertilization in vitro. Our results link the occurrence of reprogramming to a previously unappreciated requirement of oocyte-mediated nuclear reprogramming, namely DNA replication. Nuclear transfer alone affords no immediate transition from a somatic to a pluripotent gene expression pattern unless DNA replication is also in place. This study is therefore a resource to appreciate that the quest for always faster reprogramming methods may collide with a limit that is dictated by the cell cycle. PMID:24836291

  13. HYDROCARBON VAPOR DIFFUSION IN INTACT CORE SLEEVES

    EPA Science Inventory

    The diffusion of 2,2,4-trimethylpentane (TMP) and 2,2,5-trimethylhexane (TMH) vapors put of residually contaminated sandy soil from the U.S. Environmental Protection Agency (EPA) field research site at Traverse City, Michigan, was measured and modeled. The headspace of an intact ...

  14. DNA excision repair in permeable human fibroblasts

    SciTech Connect

    Kaufmann, W.K.; Bodell, W.J.; Cleaver, J.E.

    1983-01-01

    U.v. irradiation of confluent human fibroblasts activated DNA repair, aspects of which were characterized in the cells after they were permeabilized. Incubation of intact cells for 20 min between irradiation and harvesting was necessary to obtain a maximum rate of reparative DNA synthesis. Cells harvested immediately after irradiation before repair was initiated displayed only a small stimulation of DNA synthesis, indicating that permeable cells have a reduced capacity to recognize pyrimidine dimers and activate repair. The distribution of sizes of DNA strands labeled during 10 min of reparative DNA synthesis resembled that of parental DNA. However, during a 60-min incubation of permeable cells at 37 degrees C, parental DNA and DNA labeled by reparative DNA synthesis were both cleaved to smaller sizes. Cleavage also occurred in unirradiated cells, indicating that endogenous nuclease was active during incubation. Repair patches synthesized in permeable cells displayed increased sensitivity to digestion by micrococcal nuclease. However, the change in sensitivity during a chase with unlabeled DNA precursors was small, suggesting that reassembly of nucleosome structure at sites of repair was impaired. To examine whether this deficiency was due to a preponderance of incomplete or unligated repair patches, 3H-labeled (repaired) DNA was purified, then digested with exonuclease III and nuclease S1 to probe for free 3' ends and single-stranded regions. About 85% of the (3H)DNA synthesized during a 10-min pulse resisted digestion, suggesting that a major fraction of the repair patches that were filled were also ligated. U.v. light-activated DNA synthesis in permeable cells, therefore, appears to represent the continuation of reparative gap-filling at sites of excision repair activated within intact cells. Gap-filling and ligation were comparatively efficient processes in permeable cells.

  15. Small Particles Intact Capture Experiment (SPICE)

    NASA Technical Reports Server (NTRS)

    Nishioka, Ken-Ji; Carle, G. C.; Bunch, T. E.; Mendez, David J.; Ryder, J. T.

    1994-01-01

    The Small Particles Intact Capture Experiment (SPICE) will develop technologies and engineering techniques necessary to capture nearly intact, uncontaminated cosmic and interplanetary dust particles (IDP's). Successful capture of such particles will benefit the exobiology and planetary science communities by providing particulate samples that may have survived unaltered since the formation of the solar system. Characterization of these particles may contribute fundamental data to our knowledge of how these particles could have formed into our planet Earth and, perhaps, contributed to the beginnings of life. The term 'uncontaminated' means that captured cosmic and IDP particles are free of organic contamination from the capture process and the term 'nearly intact capture' means that their chemical and elemental components are not materially altered during capture. The key to capturing cosmic and IDP particles that are organic-contamination free and nearly intact is the capture medium. Initial screening of capture media included organic foams, multiple thin foil layers, and aerogel (a silica gel); but, with the exception of aerogel, the requirements of no contamination or nearly intact capture were not met. To ensure no contamination of particles in the capture process, high-purity aerogel was chosen. High-purity aerogel results in high clarity (visual clearness), a useful quality in detection and recovery of embedded captured particles from the aerogel. P. Tsou at the Jet Propulsion Laboratory (JPL) originally described the use of aerogel for this purpose and reported laboratory test results. He has flown aerogel as a 'GAS-can Lid' payload on STS-47 and is evaluating the results. The Timeband Capture Cell Experiment (TICCE), a Eureca 1 experiment, is also flying aerogel and is scheduled for recovery in late April.

  16. Epigenetic memory and cell fate reprogramming in plants

    PubMed Central

    Roudier, François

    2017-01-01

    Abstract Plants have a high intrinsic capacity to regenerate from adult tissues, with the ability to reprogram adult cell fates. In contrast, epigenetic mechanisms have the potential to stabilize cell identity and maintain tissue organization. The question is whether epigenetic memory creates a barrier to reprogramming that needs to be erased or circumvented in plant regeneration. Early evidence suggests that, while chromatin dynamics impact gene expression in the meristem, a lasting constraint on cell fate is not established until late stages of plant cell differentiation. It is not yet clear whether the plasticity of plant cells arises from the ability of cells to erase identity memory or to deploy cells that may exhibit cellular specialization but still lack an epigenetic restriction on cell fate alteration. PMID:28316791

  17. Generating pluripotent stem cells: differential epigenetic changes during cellular reprogramming.

    PubMed

    Tobin, Stacey C; Kim, Kitai

    2012-08-31

    Pluripotent stem cells hold enomous potential for therapuetic applications in tissue replacement therapy. Reprogramming somatic cells from a patient donor to generate pluripotent stem cells involves both ethical concerns inherent in the use of embryonic and oocyte-derived stem cells, as well as issues of histocompatibility. Among the various pluripotent stem cells, induced pluripotent stem cells (iPSC)--derived by ectopic expression of four reprogramming factors in donor somatic cells--are superior in terms of ethical use, histocompatibility, and derivation method. However, iPSC also show genetic and epigenetic differences that limit their differentiation potential, functionality, safety, and potential clinical utility. Here, we discuss the unique characteristics of iPSC and approaches that are being taken to overcome these limitations.

  18. Generating pluripotent stem cells: Differential epigenetic changes during cellular reprogramming

    PubMed Central

    Tobin, Stacey C.; Kim, Kitai

    2013-01-01

    Pluripotent stem cells hold enomous potential for therapuetic applications in tissue replacement therapy. Reprogramming somatic cells from a patient donor to generate pluripotent stem cells involves both ethical concerns inherent in the use of embryonic and oocyte-derived stem cells, as well as issues of histocompatibility. Among the various pluripotent stem cells, induced pluripotent stem cells (iPSC)—derived by ectopic expression of four reprogramming factors in donor somatic cells—are superior in terms of ethical use, histocompatibility, and derivation method. However, iPSC also show genetic and epigenetic differences that limit their differentiation potential, functionality, safety, and potential clinical utility. Here, we discuss the unique characteristics of iPSC and approaches that are being taken to overcome these limitations. PMID:22819821

  19. Epigenetic memory and cell fate reprogramming in plants.

    PubMed

    Birnbaum, Kenneth D; Roudier, François

    2017-02-01

    Plants have a high intrinsic capacity to regenerate from adult tissues, with the ability to reprogram adult cell fates. In contrast, epigenetic mechanisms have the potential to stabilize cell identity and maintain tissue organization. The question is whether epigenetic memory creates a barrier to reprogramming that needs to be erased or circumvented in plant regeneration. Early evidence suggests that, while chromatin dynamics impact gene expression in the meristem, a lasting constraint on cell fate is not established until late stages of plant cell differentiation. It is not yet clear whether the plasticity of plant cells arises from the ability of cells to erase identity memory or to deploy cells that may exhibit cellular specialization but still lack an epigenetic restriction on cell fate alteration.

  20. Development-Inspired Reprogramming of the Mammalian Central Nervous System

    PubMed Central

    Amamoto, Ryoji; Arlotta, Paola

    2014-01-01

    In 2012, John Gurdon and Shinya Yamanaka shared the Nobel Prize for the exciting demonstration that the identity of differentiated cells is not irreversibly determined but can be changed back to a pluripotent state under appropriate instructive signals. The principle that differentiated cells can revert to an embryonic state and even be converted directly from one cell-type into another not only turns fundamental principles of development on their head but also has profound implications for regenerative medicine. Replacement of diseased tissue with newly reprogrammed cells and modeling of human disease are concrete opportunities. Here, we focus on the central nervous system to consider whether and how reprogramming of cell identity may impact regeneration and modeling of a system historically considered immutable and hardwired. PMID:24482482

  1. Cell Fate Reprogramming by Control of Intracellular Network Dynamics

    PubMed Central

    Zañudo, Jorge G. T.; Albert, Réka

    2015-01-01

    Identifying control strategies for biological networks is paramount for practical applications that involve reprogramming a cell’s fate, such as disease therapeutics and stem cell reprogramming. Here we develop a novel network control framework that integrates the structural and functional information available for intracellular networks to predict control targets. Formulated in a logical dynamic scheme, our approach drives any initial state to the target state with 100% effectiveness and needs to be applied only transiently for the network to reach and stay in the desired state. We illustrate our method’s potential to find intervention targets for cancer treatment and cell differentiation by applying it to a leukemia signaling network and to the network controlling the differentiation of helper T cells. We find that the predicted control targets are effective in a broad dynamic framework. Moreover, several of the predicted interventions are supported by experiments. PMID:25849586

  2. Metabolic reprogramming in macrophages and dendritic cells in innate immunity

    PubMed Central

    Kelly, Beth; O'Neill, Luke AJ

    2015-01-01

    Activation of macrophages and dendritic cells (DCs) by pro-inflammatory stimuli causes them to undergo a metabolic switch towards glycolysis and away from oxidative phosphorylation (OXPHOS), similar to the Warburg effect in tumors. However, it is only recently that the mechanisms responsible for this metabolic reprogramming have been elucidated in more detail. The transcription factor hypoxia-inducible factor-1α (HIF-1α) plays an important role under conditions of both hypoxia and normoxia. The withdrawal of citrate from the tricarboxylic acid (TCA) cycle has been shown to be critical for lipid biosynthesis in both macrophages and DCs. Interference with this process actually abolishes the ability of DCs to activate T cells. Another TCA cycle intermediate, succinate, activates HIF-1α and promotes inflammatory gene expression. These new insights are providing us with a deeper understanding of the role of metabolic reprogramming in innate immunity. PMID:26045163

  3. Somatic cell reprogramming-free generation of genetically modified pigs.

    PubMed

    Tanihara, Fuminori; Takemoto, Tatsuya; Kitagawa, Eri; Rao, Shengbin; Do, Lanh Thi Kim; Onishi, Akira; Yamashita, Yukiko; Kosugi, Chisato; Suzuki, Hitomi; Sembon, Shoichiro; Suzuki, Shunichi; Nakai, Michiko; Hashimoto, Masakazu; Yasue, Akihiro; Matsuhisa, Munehide; Noji, Sumihare; Fujimura, Tatsuya; Fuchimoto, Dai-Ichiro; Otoi, Takeshige

    2016-09-01

    Genetically modified pigs for biomedical applications have been mainly generated using the somatic cell nuclear transfer technique; however, this approach requires complex micromanipulation techniques and sometimes increases the risks of both prenatal and postnatal death by faulty epigenetic reprogramming of a donor somatic cell nucleus. As a result, the production of genetically modified pigs has not been widely applied. We provide a simple method for CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 gene editing in pigs that involves the introduction of Cas9 protein and single-guide RNA into in vitro fertilized zygotes by electroporation. The use of gene editing by electroporation of Cas9 protein (GEEP) resulted in highly efficient targeted gene disruption and was validated by the efficient production of Myostatin mutant pigs. Because GEEP does not require the complex methods associated with micromanipulation for somatic reprogramming, it has the potential for facilitating the genetic modification of pigs.

  4. Somatic cell reprogramming-free generation of genetically modified pigs

    PubMed Central

    Tanihara, Fuminori; Takemoto, Tatsuya; Kitagawa, Eri; Rao, Shengbin; Do, Lanh Thi Kim; Onishi, Akira; Yamashita, Yukiko; Kosugi, Chisato; Suzuki, Hitomi; Sembon, Shoichiro; Suzuki, Shunichi; Nakai, Michiko; Hashimoto, Masakazu; Yasue, Akihiro; Matsuhisa, Munehide; Noji, Sumihare; Fujimura, Tatsuya; Fuchimoto, Dai-ichiro; Otoi, Takeshige

    2016-01-01

    Genetically modified pigs for biomedical applications have been mainly generated using the somatic cell nuclear transfer technique; however, this approach requires complex micromanipulation techniques and sometimes increases the risks of both prenatal and postnatal death by faulty epigenetic reprogramming of a donor somatic cell nucleus. As a result, the production of genetically modified pigs has not been widely applied. We provide a simple method for CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 gene editing in pigs that involves the introduction of Cas9 protein and single-guide RNA into in vitro fertilized zygotes by electroporation. The use of gene editing by electroporation of Cas9 protein (GEEP) resulted in highly efficient targeted gene disruption and was validated by the efficient production of Myostatin mutant pigs. Because GEEP does not require the complex methods associated with micromanipulation for somatic reprogramming, it has the potential for facilitating the genetic modification of pigs. PMID:27652340

  5. Development-inspired reprogramming of the mammalian central nervous system.

    PubMed

    Amamoto, Ryoji; Arlotta, Paola

    2014-01-31

    In 2012, John Gurdon and Shinya Yamanaka shared the Nobel Prize for the demonstration that the identity of differentiated cells is not irreversibly determined but can be changed back to a pluripotent state under appropriate instructive signals. The principle that differentiated cells can revert to an embryonic state and even be converted directly from one cell type into another not only turns fundamental principles of development on their heads but also has profound implications for regenerative medicine. Replacement of diseased tissue with newly reprogrammed cells and modeling of human disease are concrete opportunities. Here, we focus on the central nervous system to consider whether and how reprogramming of cell identity may affect regeneration and modeling of a system historically considered immutable and hardwired.

  6. Fibroblast heterogeneity: more than skin deep.

    PubMed

    Sorrell, J Michael; Caplan, Arnold I

    2004-02-15

    Dermal fibroblasts are a dynamic and diverse population of cells whose functions in skin in many respects remain unknown. Normal adult human skin contains at least three distinct subpopulations of fibroblasts, which occupy unique niches in the dermis. Fibroblasts from each of these niches exhibit distinctive differences when cultured separately. Specific differences in fibroblast physiology are evident in papillary dermal fibroblasts, which reside in the superficial dermis, and reticular fibroblasts, which reside in the deep dermis. Both of these subpopulations of fibroblasts differ from the fibroblasts that are associated with hair follicles. Fibroblasts engage in fibroblast-epidermal interactions during hair development and in interfollicular regions of skin. They also play an important role in cutaneous wound repair and an ever-increasing role in bioengineering of skin. Bioengineered skin currently performs important roles in providing (1) a basic understanding of skin biology, (2) a vehicle for testing topically applied products and (3) a resource for skin replacement.

  7. Exploring the mechanisms of differentiation, dedifferentiation, reprogramming and transdifferentiation.

    PubMed

    Xu, Li; Zhang, Kun; Wang, Jin

    2014-01-01

    We explored the underlying mechanisms of differentiation, dedifferentiation, reprogramming and transdifferentiation (cell type switchings) from landscape and flux perspectives. Lineage reprogramming is a new regenerative method to convert a matured cell into another cell including direct transdifferentiation without undergoing a pluripotent cell state and indirect transdifferentiation with an initial dedifferentiation-reversion (reprogramming) to a pluripotent cell state. Each cell type is quantified by a distinct valley on the potential landscape with higher probability. We investigated three driving forces for cell fate decision making: stochastic fluctuations, gene regulation and induction, which can lead to cell type switchings. We showed that under the driving forces the direct transdifferentiation process proceeds from a differentiated cell valley to another differentiated cell valley through either a distinct stable intermediate state or a certain series of unstable indeterminate states. The dedifferentiation process proceeds through a pluripotent cell state. Barrier height and the corresponding escape time from the valley on the landscape can be used to quantify the stability and efficiency of cell type switchings. We also uncovered the mechanisms of the underlying processes by quantifying the dominant biological paths of cell type switchings on the potential landscape. The dynamics of cell type switchings are determined by both landscape gradient and flux. The flux can lead to the deviations of the dominant biological paths for cell type switchings from the naively expected landscape gradient path. As a result, the corresponding dominant paths of cell type switchings are irreversible. We also classified the mechanisms of cell fate development from our landscape theory: super-critical pitchfork bifurcation, sub-critical pitchfork bifurcation, sub-critical pitchfork with two saddle-node bifurcation, and saddle-node bifurcation. Our model showed good

  8. Oxamflatin Treatment Enhances Cloned Porcine Embryo Development and Nuclear Reprogramming*

    PubMed Central

    Mao, Jiude; Zhao, Ming-Tao; Whitworth, Kristin M.; Spate, Lee D.; Walters, Eric M.; O'Gorman, Chad; Lee, Kiho; Samuel, Melissa S.; Murphy, Clifton N.; Wells, Kevin; Rivera, Rocio M.

    2015-01-01

    Abstract Faulty epigenetic reprogramming of somatic nuclei is thought to be the main reason for low cloning efficiency by somatic cell nuclear transfer (SCNT). Histone deacetylase inhibitors (HDACi), such as Scriptaid, improve developmental competence of SCNT embryos in several species. Another HDACi, Oxamflatin, is about 100 times more potent than Scriptaid in the ability to inhibit nuclear-specific HDACs. The present study determined the effects of Oxamflatin treatment on embryo development, DNA methylation, and gene expression. Oxamflatin treatment enhanced blastocyst formation of SCNT embryos in vitro. Embryo transfer produced more pigs born and fewer mummies from the Oxamflatin-treated group compared to the Scriptaid-treated positive control. Oxamflatin also decreased DNA methylation of POU5F1 regulatory elements and centromeric repeat elements in day-7 blastocysts. When compared to in vitro–fertilized (IVF) embryos, the methylation status of POU5F1, NANOG, and centromeric repeat was similar in the cloned embryos, indicating these genes were successfully reprogrammed. However, compared to the lack of methylation of XIST in day-7 IVF embryos, a higher methylation level in day-7 cloned embryos was observed, implying that X chromosomes were activated in day-7 IVF blastocysts, but were not fully activated in cloned embryos, i.e., reprogramming of XIST was delayed. A time-course analysis of XIST DNA methylation on day-13, -15, -17, and -19 in vivo embryos revealed that XIST methylation initiated at about day 13 and was not completed by day 19. The methylation of the XIST gene in day-19 control cloned embryos was delayed again when compared to in vivo embryos. However, methylation of XIST in Oxamflatin-treated embryos was comparable with in vivo embryos, which further demonstrated that Oxamflatin could accelerate the delayed reprogramming of XIST gene and thus might improve cloning efficiency. PMID:25548976

  9. Developmental Programming of Adult Disease: Reprogramming by Melatonin?

    PubMed Central

    Tain, You-Lin; Huang, Li-Tung; Hsu, Chien-Ning

    2017-01-01

    Adult-onset chronic non-communicable diseases (NCDs) can originate from early life through so-called the “developmental origins of health and disease” (DOHaD) or “developmental programming”. The DOHaD concept offers the “reprogramming” strategy to shift the treatment from adulthood to early life, before clinical disease is apparent. Melatonin, an endogenous indoleamine produced by the pineal gland, has pleiotropic bioactivities those are beneficial in a variety of human diseases. Emerging evidence support that melatonin is closely inter-related to other proposed mechanisms contributing to the developmental programming of a variety of chronic NCDs. Recent animal studies have begun to unravel the multifunctional roles of melatonin in many experimental models of developmental programming. Even though some progress has been made in research on melatonin as a reprogramming strategy to prevent DOHaD-related NCDs, future human studies should aim at filling the translational gap between animal models and clinical trials. Here, we review several key themes on the reprogramming effects of melatonin in DOHaD research. We have particularly focused on the following areas: mechanisms of developmental programming; the interrelationship between melatonin and mechanisms underlying developmental programming; pathophysiological roles of melatonin in pregnancy and fetal development; and insight provided by animal models to support melatonin as a reprogramming therapy. Rates of NCDs are increasing faster than anticipated all over the world. Hence, there is an urgent need to understand reprogramming mechanisms of melatonin and to translate experimental research into clinical practice for halting a growing list of DOHaD-related NCDs. PMID:28212315

  10. Reprogramming of cassava (Manihot esculenta) microspores towards sporophytic development.

    PubMed

    Perera, P I P; Ordoñez, C A; Dedicova, B; Ortega, P E M

    2014-05-21

    Gametes have the unique potential to enter the sporophytic pathway, called androgenesis. The plants produced are usually haploid and recombinant due to the preceding meiosis and they can double their chromosome number to form doubled haploids, which are completely homozygous. Availability of the doubled haploids facilitates mapping the genes of agronomically important traits, shortening the time of the breeding process required to produce new hybrids and homozygous varieties, and saving the time and cost for inbreeding. This study aimed to test the feasibility of using isolated and in vitro cultured immature cassava (Manihot esculenta) microspores to reprogramme and initiate sporophytic development. Different culture media and different concentrations of two ion components (Cu(2+) and Fe(2+)) were tested in two genotypes of cassava. External structural changes, nuclear divisions and cellular changes during reprogramming were analysed by scanning electron microscopy, by staining with 4',6-diamidino-2-phenylindole, and through classical histology and transmission electron microscopy. In two cassava genotypes, different developmental stages of microspores were found to initiate sporophytic cell divisions, that is, with tetrads of TMS 60444 and with mid or late uni-nucleate microspores of SM 1219-9. In the modified NLN medium (NLNS), microspore enlargements were observed. The medium supplemented with either sodium ferrous ethylene-diamine-tetraacetic acid (NaFeEDTA) or CuSO4·5H2O induced sporophytic cell division in both genotypes. A low frequency of the reprogramming and the presence of non-responsive microspores among the responsive ones in tetrads were found to be related to the viability and exine formation of the microspores. The present study clearly demonstrated that reprogramming occurs much faster in isolated microspore culture than in anther culture. This paves the way for the development of an efficient technique for the production of homozygous lines in

  11. Exploring the Mechanisms of Differentiation, Dedifferentiation, Reprogramming and Transdifferentiation

    PubMed Central

    Xu, Li; Zhang, Kun; Wang, Jin

    2014-01-01

    We explored the underlying mechanisms of differentiation, dedifferentiation, reprogramming and transdifferentiation (cell type switchings) from landscape and flux perspectives. Lineage reprogramming is a new regenerative method to convert a matured cell into another cell including direct transdifferentiation without undergoing a pluripotent cell state and indirect transdifferentiation with an initial dedifferentiation-reversion (reprogramming) to a pluripotent cell state. Each cell type is quantified by a distinct valley on the potential landscape with higher probability. We investigated three driving forces for cell fate decision making: stochastic fluctuations, gene regulation and induction, which can lead to cell type switchings. We showed that under the driving forces the direct transdifferentiation process proceeds from a differentiated cell valley to another differentiated cell valley through either a distinct stable intermediate state or a certain series of unstable indeterminate states. The dedifferentiation process proceeds through a pluripotent cell state. Barrier height and the corresponding escape time from the valley on the landscape can be used to quantify the stability and efficiency of cell type switchings. We also uncovered the mechanisms of the underlying processes by quantifying the dominant biological paths of cell type switchings on the potential landscape. The dynamics of cell type switchings are determined by both landscape gradient and flux. The flux can lead to the deviations of the dominant biological paths for cell type switchings from the naively expected landscape gradient path. As a result, the corresponding dominant paths of cell type switchings are irreversible. We also classified the mechanisms of cell fate development from our landscape theory: super-critical pitchfork bifurcation, sub-critical pitchfork bifurcation, sub-critical pitchfork with two saddle-node bifurcation, and saddle-node bifurcation. Our model showed good

  12. [Fibroblast growth factor-2].

    PubMed

    Faitová, J

    2004-01-01

    Fibroblast growth factor-2 is a member of a large family of proteins that bind heparin and heparan sulfate and modulate the function of a wide range of cell types. FGF-2 occurs in several isoforms resulting from alternative initiations of traslation: an 18 kDa cytoplasmic isoform and four larger molecular weight nuclear isoforms (22, 22.5, 24 and 34 kDa). It acts mainly through a paracrine/autocrine mechanism involving high affinity transmembrane receptors and heparan sulfate proteoglycan low affinity receptors. It is expressed mostly in tissues of mesoderm and neuroectoderm origin, and plays an important role in mesoderm induction, stimulates the growth and development of the new blood vessels (angiogenesis), normal wound healing and tissue development. FGF-2 positively regulates hematopoiesis by acting on various cellular targets: stromal cells, early and committed hematopoietic progenitors and possibly some mature blood cells. FGF-2 is a potent hematopoietic growth factor that is likely to play an important role in physiological and pathological hematopoiesis.

  13. Prostacyclin analogs inhibit fibroblast migration.

    PubMed

    Kohyama, Tadashi; Liu, Xiangde; Kim, Hui Jung; Kobayashi, Tetsu; Ertl, Ronald F; Wen, Fu-Qiang; Takizawa, Hajime; Rennard, Stephen I

    2002-08-01

    The controlled accumulation of fibroblasts to sites of inflammation is crucial to effective tissue repair after injury. Either inadequate or excessive accumulation of fibroblasts could result in abnormal tissue function. Prostacyclin (PGI(2)) is a potent mediator in the coagulation and inflammatory processes. The aim of this study was to investigate the effect of PGI(2) on chemotaxis of human fetal lung fibroblasts (HFL-1). Using the blind well chamber technique, we found that the PGI(2) analog carbaprostacyclin (10(-6) M) inhibited HFL-1 chemotaxis to human plasma fibronectin (20 microg/ml) 58.0 +/- 13.2% (P < 0.05) and to platelet-derived growth factor (PDGF)-BB (10 ng/ml) 48.7 +/- 4.6% (P < 0.05). Checkerboard analysis demonstrated that carbaprostacyclin inhibits both directed and undirected migration. The inhibitory effect of the carbaprostacyclin was concentration dependent and blocked by the cAMP-dependent protein kinase (PKA) inhibitor KT-5720, suggesting that a cAMP-PKA pathway may be involved in the process. Two other PGI(2) analogs, ciprostene and dehydro-15-cyclohexyl carbaprostacyclin (both 10(-6) M), significantly inhibited fibroblast migration to fibronectin. In summary, PGI(2) appears to inhibit fibroblast chemotaxis to fibronectin and PDGF-BB. Such an effect may contribute to the regulation of fibroblasts in wound healing and could contribute to the pathogenesis of diseases characterized by abnormal tissue repair remodeling.

  14. Induced Pluripotent Stem Cells: Emerging Techniques for Nuclear Reprogramming

    PubMed Central

    Han, Ji Woong

    2011-01-01

    Abstract Introduction of four transcription factors, Oct3/4, Sox2, Klf4, and c-Myc, can successfully reprogram somatic cells into embryonic stem (ES)-like cells. These cells, which are referred to as induced pluripotent stem (iPS) cells, closely resemble embryonic stem cells in genomic, cell biologic, and phenotypic characteristics, and the creation of these special cells was a major triumph in cell biology. In contrast to pluripotent stem cells generated by somatic cell nuclear-transfer (SCNT) or ES cells derived from the inner cell mass (ICM) of the blastocyst, direct reprogramming provides a convenient and reliable means of generating pluripotent stem cells. iPS cells have already shown incredible potential for research and for therapeutic applications in regenerative medicine within just a few years of their discovery. In this review, current techniques of generating iPS cells and mechanisms of nuclear reprogramming are reviewed, and the potential for therapeutic applications is discussed. Antioxid. Redox Signal. 15, 1799–1820. PMID:21194386

  15. Reprogramming of glucose metabolism in hepatocellular carcinoma: Progress and prospects

    PubMed Central

    Shang, Run-Ze; Qu, Shi-Bin; Wang, De-Sheng

    2016-01-01

    Hepatocellular carcinoma (HCC) is one of the most lethal cancers, and its rate of incidence is rising annually. Despite the progress in diagnosis and treatment, the overall prognoses of HCC patients remain dismal due to the difficulties in early diagnosis and the high level of tumor invasion, metastasis and recurrence. It is urgent to explore the underlying mechanism of HCC carcinogenesis and progression to find out the specific biomarkers for HCC early diagnosis and the promising target for HCC chemotherapy. Recently, the reprogramming of cancer metabolism has been identified as a hallmark of cancer. The shift from the oxidative phosphorylation metabolic pathway to the glycolysis pathway in HCC meets the demands of rapid cell proliferation and offers a favorable microenvironment for tumor progression. Such metabolic reprogramming could be considered as a critical link between the different HCC genotypes and phenotypes. The regulation of metabolic reprogramming in cancer is complex and may occur via genetic mutations and epigenetic modulations including oncogenes, tumor suppressor genes, signaling pathways, noncoding RNAs, and glycolytic enzymes etc. Understanding the regulatory mechanisms of glycolysis in HCC may enrich our knowledge of hepatocellular carcinogenesis and provide important foundations in the search for novel diagnostic biomarkers and promising therapeutic targets for HCC. PMID:28018100

  16. GATA family members as inducers for cellular reprogramming to pluripotency

    PubMed Central

    Shu, Jian; Zhang, Ke; Zhang, Minjie; Yao, Anzhi; Shao, Sida; Du, Fengxia; Yang, Caiyun; Chen, Wenhan; Wu, Chen; Yang, Weifeng; Sun, Yingli; Deng, Hongkui

    2015-01-01

    Members of the GATA protein family play important roles in lineage specification and transdifferentiation. Previous reports show that some members of the GATA protein family can also induce pluripotency in somatic cells by substituting for Oct4, a key pluripotency-associated factor. However, the mechanism linking lineage-specifying cues and the activation of pluripotency remains elusive. Here, we report that all GATA family members can substitute for Oct4 to induce pluripotency. We found that all members of the GATA family could inhibit the overrepresented ectodermal-lineage genes, which is consistent with previous reports indicating that a balance of different lineage-specifying forces is important for the restoration of pluripotency. A conserved zinc-finger DNA-binding domain in the C-terminus is critical for the GATA family to induce pluripotency. Using RNA-seq and ChIP-seq, we determined that the pluripotency-related gene Sall4 is a direct target of GATA family members during reprogramming and serves as a bridge linking the lineage-specifying GATA family to the pluripotency circuit. Thus, the GATA family is the first protein family of which all members can function as inducers of the reprogramming process and can substitute for Oct4. Our results suggest that the role of GATA family in reprogramming has been underestimated and that the GATA family may serve as an important mediator of cell fate conversion. PMID:25591928

  17. Stress Response and Perinatal Reprogramming: Unraveling (Mal)adaptive Strategies

    PubMed Central

    Musazzi, Laura; Marrocco, Jordan

    2016-01-01

    Environmental stressors induce coping strategies in the majority of individuals. The stress response, involving the activation of the hypothalamic-pituitary-adrenocortical axis and the consequent release of corticosteroid hormones, is indeed aimed at promoting metabolic, functional, and behavioral adaptations. However, behavioral stress is also associated with fast and long-lasting neurochemical, structural, and behavioral changes, leading to long-term remodeling of glutamate transmission, and increased susceptibility to neuropsychiatric disorders. Of note, early-life events, both in utero and during the early postnatal life, trigger reprogramming of the stress response, which is often associated with loss of stress resilience and ensuing neurobehavioral (mal)adaptations. Indeed, adverse experiences in early life are known to induce long-term stress-related neuropsychiatric disorders in vulnerable individuals. Here, we discuss recent findings about stress remodeling of excitatory neurotransmission and brain morphology in animal models of behavioral stress. These changes are likely driven by epigenetic factors that lie at the core of the stress-response reprogramming in individuals with a history of perinatal stress. We propose that reprogramming mechanisms may underlie the reorganization of excitatory neurotransmission in the short- and long-term response to stressful stimuli. PMID:27057367

  18. A case of cellular alchemy: lineage reprogramming and its potential in regenerative medicine.

    PubMed

    Asuelime, Grace E; Shi, Yanhong

    2012-08-01

    The field of regenerative medicine is rapidly gaining momentum as an increasing number of reports emerge concerning the induced conversions observed in cellular fate reprogramming. While in recent years, much attention has been focused on the conversion of fate-committed somatic cells to an embryonic-like or pluripotent state, there are still many limitations associated with the applications of induced pluripotent stem cell reprogramming, including relatively low reprogramming efficiency, the times required for the reprogramming event to take place, the epigenetic instability, and the tumorigenicity associated with the pluripotent state. On the other hand, lineage reprogramming involves the conversion from one mature cell type to another without undergoing conversion to an unstable intermediate. It provides an alternative approach in regenerative medicine that has a relatively lower risk of tumorigenesis and increased efficiency within specific cellular contexts. While lineage reprogramming provides exciting potential, there is still much to be assessed before this technology is ready to be applied in a clinical setting.

  19. A Blueprint for a Synthetic Genetic Feedback Controller to Reprogram Cell Fate.

    PubMed

    Del Vecchio, Domitilla; Abdallah, Hussein; Qian, Yili; Collins, James J

    2017-01-25

    To artificially reprogram cell fate, experimentalists manipulate the gene regulatory networks (GRNs) that maintain a cell's phenotype. In practice, reprogramming is often performed by constant overexpression of specific transcription factors (TFs). This process can be unreliable and inefficient. Here, we address this problem by introducing a new approach to reprogramming based on mathematical analysis. We demonstrate that reprogramming GRNs using constant overexpression may not succeed in general. Instead, we propose an alternative reprogramming strategy: a synthetic genetic feedback controller that dynamically steers the concentration of a GRN's key TFs to any desired value. The controller works by adjusting TF expression based on the discrepancy between desired and actual TF concentrations. Theory predicts that this reprogramming strategy is guaranteed to succeed, and its performance is independent of the GRN's structure and parameters, provided that feedback gain is sufficiently high. As a case study, we apply the controller to a model of induced pluripotency in stem cells.

  20. Injury-Induced Senescence Enables In Vivo Reprogramming in Skeletal Muscle.

    PubMed

    Chiche, Aurélie; Le Roux, Isabelle; von Joest, Mathieu; Sakai, Hiroshi; Aguín, Sabela Búa; Cazin, Coralie; Salam, Rana; Fiette, Laurence; Alegria, Olinda; Flamant, Patricia; Tajbakhsh, Shahragim; Li, Han

    2017-03-02

    In vivo reprogramming is a promising approach for tissue regeneration in response to injury. Several examples of in vivo reprogramming have been reported in a variety of lineages, but some including skeletal muscle have so far proven refractory. Here, we show that acute and chronic injury enables transcription-factor-mediated reprogramming in skeletal muscle. Lineage tracing indicates that this response frequently originates from Pax7+ muscle stem cells. Injury is associated with accumulation of senescent cells, and advanced aging or local irradiation further enhanced in vivo reprogramming, while selective elimination of senescent cells reduced reprogramming efficiency. The effect of senescence appears to be, at least in part, due to the release of interleukin 6 (IL-6), suggesting a potential link with the senescence-associated secretory phenotype. Collectively, our findings highlight a beneficial paracrine effect of injury-induced senescence on cellular plasticity, which will be important for devising strategies for reprogramming-based tissue repair.

  1. Mitochondrial iron and energetic dysfunction distinguish fibroblasts and induced neurons from pantothenate kinase-associated neurodegeneration patients

    PubMed Central

    Santambrogio, Paolo; Dusi, Sabrina; Guaraldo, Michela; Rotundo, Luisa Ida; Broccoli, Vania; Garavaglia, Barbara; Tiranti, Valeria; Levi, Sonia

    2015-01-01

    Pantothenate kinase-associated neurodegeneration is an early onset autosomal recessive movement disorder caused by mutation of the pantothenate kinase-2 gene, which encodes a mitochondrial enzyme involved in coenzyme A synthesis. The disorder is characterised by high iron levels in the brain, although the pathological mechanism leading to this accumulation is unknown. To address this question, we tested primary skin fibroblasts from three patients and three healthy subjects, as well as neurons induced by direct fibroblast reprogramming, for oxidative status, mitochondrial functionality and iron parameters. The patients' fibroblasts showed altered oxidative status, reduced antioxidant defence, and impaired cytosolic and mitochondrial aconitase activities compared to control cells. Mitochondrial iron homeostasis and functionality analysis of patient fibroblasts indicated increased labile iron pool content and reactive oxygen species development, altered mitochondrial shape, decreased membrane potential and reduced ATP levels. Furthermore, analysis of induced neurons, performed at a single cell level, confirmed some of the results obtained in fibroblasts, indicating an altered oxidative status and signs of mitochondrial dysfunction, possibly due to iron mishandling. Thus, for the first time, altered biological processes have been identified in vitro in live diseased neurons. Moreover, the obtained induced neurons can be considered a suitable human neuronal model for the identification of candidate therapeutic compounds for this disease. PMID:25836419

  2. Mitochondrial iron and energetic dysfunction distinguish fibroblasts and induced neurons from pantothenate kinase-associated neurodegeneration patients.

    PubMed

    Santambrogio, Paolo; Dusi, Sabrina; Guaraldo, Michela; Rotundo, Luisa Ida; Broccoli, Vania; Garavaglia, Barbara; Tiranti, Valeria; Levi, Sonia

    2015-09-01

    Pantothenate kinase-associated neurodegeneration is an early onset autosomal recessive movement disorder caused by mutation of the pantothenate kinase-2 gene, which encodes a mitochondrial enzyme involved in coenzyme A synthesis. The disorder is characterised by high iron levels in the brain, although the pathological mechanism leading to this accumulation is unknown. To address this question, we tested primary skin fibroblasts from three patients and three healthy subjects, as well as neurons induced by direct fibroblast reprogramming, for oxidative status, mitochondrial functionality and iron parameters. The patients' fibroblasts showed altered oxidative status, reduced antioxidant defence, and impaired cytosolic and mitochondrial aconitase activities compared to control cells. Mitochondrial iron homeostasis and functionality analysis of patient fibroblasts indicated increased labile iron pool content and reactive oxygen species development, altered mitochondrial shape, decreased membrane potential and reduced ATP levels. Furthermore, analysis of induced neurons, performed at a single cell level, confirmed some of the results obtained in fibroblasts, indicating an altered oxidative status and signs of mitochondrial dysfunction, possibly due to iron mishandling. Thus, for the first time, altered biological processes have been identified in vitro in live diseased neurons. Moreover, the obtained induced neurons can be considered a suitable human neuronal model for the identification of candidate therapeutic compounds for this disease.

  3. Xenopus egg cytoplasm with intact actin.

    PubMed

    Field, Christine M; Nguyen, Phuong A; Ishihara, Keisuke; Groen, Aaron C; Mitchison, Timothy J

    2014-01-01

    We report optimized methods for preparing Xenopus egg extracts without cytochalasin D, that we term "actin-intact egg extract." These are undiluted egg cytoplasm that contains abundant organelles, and glycogen which supplies energy, and represents the least perturbed cell-free cytoplasm preparation we know of. We used this system to probe cell cycle regulation of actin and myosin-II dynamics (Field et al., 2011), and to reconstitute the large, interphase asters that organize early Xenopus embryos (Mitchison et al., 2012; Wühr, Tan, Parker, Detrich, & Mitchison, 2010). Actin-intact Xenopus egg extracts are useful for analysis of actin dynamics, and interaction of actin with other cytoplasmic systems, in a cell-free system that closely mimics egg physiology, and more generally for probing the biochemistry and biophysics of the egg, zygote, and early embryo. Detailed protocols are provided along with assays used to check cell cycle state and tips for handling and storing undiluted egg extracts.

  4. PINOCYTOSIS IN FIBROBLASTS

    PubMed Central

    Steinman, Ralph M.; Silver, Jonathan M.; Cohn, Zanvil A.

    1974-01-01

    Horseradish peroxidase (HRP) was used as a marker to determine the rate of ongoing pinocytosis in several fibroblast cell lines. The enzyme was interiorized in the fluid phase without evidence of adsorption to the cell surface. Cytochemical reaction product was not found on the cell surface and was visualized only within intracellular vesicles and granules. Uptake was directly proportional to the administered concentration of HRP and to the duration of exposure. The rate of HRP uptake was 0.0032–0.0035% of the administered load per 106 cells per hour for all cells studied with one exception: L cells, after reaching confluence, progressively increased their pinocytic activity two- to fourfold. After uptake of HRP, L cells inactivated HRP with a half-life of 6–8 h. Certain metabolic requirements of pinocytosis were then studied in detail in L cells. Raising the environmental temperature increased pinocytosis over a range of 2–38°C. The Q10 was 2.7 and the activation energy, 17.6 kcal/mol. Studies on the levels of cellular ATP in the presence of various metabolic inhibitors (fluoride, 2-desoxyglycose, azide, and cyanide) showed that L cells synthesized ATP by both glycolytic and respiratory pathways. A combination of a glycolytic and a respiratory inhibitor was needed to depress cellular ATP levels as well as pinocytic activity to 10–20% of control values, whereas drugs administered individually had only partial effects. In spite of the availability of an accurate quantitative assay for fluid and solute uptake, the function of pinocytosis in tissue culture cells remains unknown. PMID:4140194

  5. The Epigenetic Reprogramming Roadmap in Generation of iPSCs from Somatic Cells.

    PubMed

    Brix, Jacob; Zhou, Yan; Luo, Yonglun

    2015-12-20

    Reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) is a comprehensive epigenetic process involving genome-wide modifications of histones and DNA methylation. This process is often incomplete, which subsequently affects iPSC reprogramming, pluripotency, and differentiation capacity. Here, we review the epigenetic changes with a focus on histone modification (methylation and acetylation) and DNA modification (methylation) during iPSC induction. We look at changes in specific epigenetic signatures, aberrations and epigenetic memory during reprogramming and small molecules influencing the epigenetic reprogramming of somatic cells. Finally, we discuss how to improve iPSC generation and pluripotency through epigenetic manipulations.

  6. Establishment of Hepatocellular Cancer Induced Pluripotent Stem Cells Using a Reprogramming Technique

    PubMed Central

    Kim, Han Joon; Jeong, Jaemin; Park, Sunhoo; Jin, Young-Woo; Lee, Seung-Sook; Lee, Seung Bum; Choi, Dongho

    2017-01-01

    Background/Aims Cancer is known to be a disease by many factors. However, specific results of reprogramming by pluripotency-related transcription factors remain to be scarcely reported. Here, we verified potential effects of pluripotent-related genes in hepatocellular carcinoma cancer cells. Methods To better understand reprogramming of cancer cells in different genetic backgrounds, we used four liver cancer cell lines representing different states of p53 (HepG2, Hep3B, Huh7 and PLC). Retroviral-mediated introduction of reprogramming related genes (KLF4, Oct4, Sox2, and Myc) was used to induce the expression of proteins related to a pluripotent status in liver cancer cells. Results Hep3B cells (null p53) exhibited a higher efficiency of reprogramming in comparison to the other liver cancer cell lines. The reprogrammed Hep3B cells acquired similar characteristics to pluripotent stem cells. However, loss of stemness in Hep3B-iPCs was detected during continual passage. Conclusions We demonstrated that reprogramming was achieved in tumor cells through retroviral induction of genes associated with reprogramming. Interestingly, the reprogrammed pluripotent cancer cells (iPCs) were very different from original cancer cells in terms of colony shape and expressed markers. The induction of pluripotency of liver cancer cells correlated with the status of p53, suggesting that different expression level of p53 in cancer cells may affect their reprogramming. PMID:27728962

  7. Silica Aerogel Captures Cosmic Dust Intact

    NASA Technical Reports Server (NTRS)

    Tsou, P.

    1994-01-01

    The mesostructure of silica aerogel resembles stings of grapes, ranging in size from 10 to 100 angstrom. This fine mesostructure transmits nearly 90 percent of incident light in the visible, while providing sufficiently gentle dissipation of the kinetric energy of hypervelocity cosmic dust particles to permit their intact capture. We introduced silica aerogel in 1987 as capture medium to take advantage of its low density, fine mesostruicture and most importantly, its transparency, allowing optical location of captured micron sized particles.

  8. Genetic reprogramming of transcription factor ap-2gamma in bovine somatic cell nuclear transfer preimplantation embryos and placentomes.

    PubMed

    Aston, Kenneth I; Li, Gugan-Peng; Hicks, Brady A; Winger, Quinton A; White, Kenneth L

    2009-03-01

    Bovine somatic cell nuclear transfer (SCNT) efficiency remains very low despite a tremendous amount of research devoted to its improvement over the past decade. Frequent early and mid-gestational losses are commonly accompanied by placental abnormalities. A transcription factor, activating protein AP-2gamma, has been shown to be necessary for proper placental development in the mouse. We first evaluated the expression of the gene coding for AP-2gamma (Tfap2c) in several bovine fibroblast donor cell lines and found it was not expressed. Subsequently we determined the expression profile of Tfap2c in oocytes and various stages of preimplantation in vitro fertilized (IVF) embryos. Tfap2c was undetectable in oocytes and early embryos, and was detectable at relatively high levels in morula and blastocyst IVF embryos. The lack of expression in oocytes and donor cells means Tfap2c must be induced in the zygote at the morula stage in properly reprogrammed embryos. SCNT embryos expressed Tfap2c at the eight-cell stage, 2 days earlier than control embryos. Control embryos first expressed Tfap2c at the morula stage, and at this stage Tfap2c was significantly lower in the SCNT embryos. No differences in expression were detected at the blastocyst stage. To determine whether Tfap2c was properly reprogrammed in the placenta of SCNT pregnancies, we evaluated its expression in cotyledons and caruncles of SCNT and control pregnancies between days 55 and 90 gestation. Expression of Tfap2c in caruncles significantly increased between days 55 and 90, while expression in cotyledons was relatively consistent over that same period. Expression levels in SCNT tissues were not different from controls. This data indicates Tfap2c expression is altered in early preimplantation SCNT embryos, which may have developmental consequences resulting from genes influenced by Tfap2c, but expression was not different at the blastocyst stage and in placentomes.

  9. Cells Lacking β-Actin are Genetically Reprogrammed and Maintain Conditional Migratory Capacity*

    PubMed Central

    Tondeleir, Davina; Lambrechts, Anja; Müller, Matthias; Jonckheere, Veronique; Doll, Thierry; Vandamme, Drieke; Bakkali, Karima; Waterschoot, Davy; Lemaistre, Marianne; Debeir, Olivier; Decaestecker, Christine; Hinz, Boris; Staes, An; Timmerman, Evy; Colaert, Niklaas; Gevaert, Kris; Vandekerckhove, Joël; Ampe, Christophe

    2012-01-01

    Vertebrate nonmuscle cells express two actin isoforms: cytoplasmic β- and γ-actin. Because of the presence and localized translation of β-actin at the leading edge, this isoform is generally accepted to specifically generate protrusive forces for cell migration. Recent evidence also implicates β-actin in gene regulation. Cell migration without β-actin has remained unstudied until recently and it is unclear whether other actin isoforms can compensate for this cytoplasmic function and/or for its nuclear role. Primary mouse embryonic fibroblasts lacking β-actin display compensatory expression of other actin isoforms. Consistent with this preservation of polymerization capacity, β-actin knockout cells have unchanged lamellipodial protrusion rates despite a severe migration defect. To solve this paradox we applied quantitative proteomics revealing a broad genetic reprogramming of β-actin knockout cells. This also explains why reintroducing β-actin in knockout cells does not restore the affected cell migration. Pathway analysis suggested increased Rho-ROCK signaling, consistent with observed phenotypic changes. We therefore developed and tested a model explaining the phenotypes in β-actin knockout cells based on increased Rho-ROCK signaling and increased TGFβ production resulting in increased adhesion and contractility in the knockout cells. Inhibiting ROCK or myosin restores migration of β-actin knockout cells indicating that other actins compensate for β-actin in this process. Consequently, isoactins act redundantly in providing propulsive forces for cell migration, but β-actin has a unique nuclear function, regulating expression on transcriptional and post-translational levels, thereby preventing myogenic differentiation. PMID:22448045

  10. Directed Dedifferentiation Using Partial Reprogramming Induces Invasive Phenotype in Melanoma Cells.

    PubMed

    Knappe, Nathalie; Novak, Daniel; Weina, Kasia; Bernhardt, Mathias; Reith, Maike; Larribere, Lionel; Hölzel, Michael; Tüting, Thomas; Gebhardt, Christoffer; Umansky, Viktor; Utikal, Jochen

    2016-04-01

    The combination of cancer-focused studies and research related to nuclear reprogramming has gained increasing importance since both processes-reprogramming towards pluripotency and malignant transformation-share essential features. Studies have revealed that incomplete reprogramming of somatic cells leads to malignant transformation indicating that epigenetic regulation associated with iPSC generation can drive cancer development [J Mol Cell Biol 2011;341-350; Cell 2012;151:1617-1632; Cell 2014;156:663-677]. However, so far it is unclear whether incomplete reprogramming also affects cancer cells and their function. In the context of melanoma, dedifferentiation correlates to therapy resistance in mouse studies and has been documented in melanoma patients [Nature 2012;490:412-416; Clin Cancer Res 2014;20:2498-2499]. Therefore, we sought to investigate directed dedifferentiation using incomplete reprogramming of melanoma cells. Using a murine model we investigated the effects of partial reprogramming on the cellular plasticity of melanoma cells. We demonstrate for the first time that induced partial reprogramming results in a reversible phenotype switch in melanoma cells. Partially reprogrammed cells at day 12 after transgene induction display elevated invasive potential in vitro and increased lung colonization in vivo. Additionally, using global gene expression analysis of partially reprogrammed cells, we identified SNAI3 as a novel invasion-related marker in human melanoma. SNAI3 expression correlates with tumor thickness in primary melanomas and thus, may be of prognostic value. In summary, we show that investigating intermediate states during the process of reprogramming melanoma cells can reveal novel insights into the pathogenesis of melanoma progression. We propose that deeper analysis of partially reprogrammed melanoma cells may contribute to identification of yet unknown signaling pathways that can drive melanoma progression.

  11. Comparison of reprogramming genes in induced pluripotent stem cells and nuclear transfer cloned embryos.

    PubMed

    Duan, Lian; Wang, Zhendong; Shen, Jingling; Shan, Zhiyan; Shen, Xinghui; Wu, Yanshuang; Sun, Ruizhen; Li, Tong; Yuan, Rui; Zhao, Qiaoshi; Bai, Guangyu; Gu, Yanli; Jin, Lianhong; Lei, Lei

    2014-08-01

    The most effective reprogramming methods, somatic cell nuclear transfer (SCNT) and induced pluripotent stem cells (iPSCs), are widely used in biological research and regenerative medicine, yet the mechanism that reprograms somatic cells to totipotency remains unclear and thus reprogramming efficiency is still low. Microarray technology has been employed in analyzing the transcriptomes changes during iPS reprogramming. Unfortunately, it is difficult to obtain enough DNA from SCNT reconstructed embryos to take advantage of this technology. In this study, we aimed to identify critical genes from the transcriptional profile for iPS reprogramming and compared expression levels of these genes in SCNT reprogramming. By integrating gene expression information from microarray databases and published studies comparing somatic cells with either miPSCs or mouse embryonic stem cells (ESCs), we obtained two lists of co-upregulated genes. The gene ontology (GO) enriched analysis of these two lists demonstrated that the reprogramming process is associated with numerous biological processes. Specifically, we selected 32 genes related to heterochromatin, embryonic development, and cell cycle from our co-upregulated gene datasets and examined the gene expression level in iPSCs and SCNT embryos by qPCR. The results revealed that some reprogramming related genes in iPSCs were also expressed in SCNT reprogramming. We established the network of gene interactions that occur with genes differentially expressed in iPS and SCNT reprogramming and then performed GO analysis on the genes in the network. The network genes function in chromatin organization, heterochromatin, transcriptional regulation, and cell cycle. Further researches to improve reprogramming efficiency, especially in SCNT, will focus on functional studies of these selected genes.

  12. Cardiac Fibrosis: The Fibroblast Awakens

    PubMed Central

    Travers, Joshua G.; Kamal, Fadia A.; Robbins, Jeffrey; Yutzey, Katherine E.; Blaxall, Burns C.

    2016-01-01

    Myocardial fibrosis is a significant global health problem associated with nearly all forms of heart disease. Cardiac fibroblasts comprise an essential cell type in the heart that is responsible for the homeostasis of the extracellular matrix; however upon injury, these cells transform to a myofibroblast phenotype and contribute to cardiac fibrosis. This remodeling involves pathological changes that include chamber dilation, cardiomyocyte hypertrophy and apoptosis, and ultimately leads to the progression to heart failure. Despite the critical importance of fibrosis in cardiovascular disease, our limited understanding of this cell population impedes the development of potential therapies that effectively target this cell type and its pathological contribution to disease progression. This review summarizes current knowledge regarding the origins and roles of fibroblasts, mediators and signaling pathways known to influence fibroblast function after myocardial injury, as well as novel therapeutic strategies under investigation to attenuate cardiac fibrosis. PMID:26987915

  13. 50 CFR 622.493 - Landing Caribbean queen conch intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... conch intact. (a) A Caribbean queen conch in or from the Caribbean EEZ must be maintained with meat and shell intact. (b) The operator of a vessel that fishes in the EEZ is responsible for ensuring...

  14. 50 CFR 622.493 - Landing Caribbean queen conch intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... conch intact. (a) A Caribbean queen conch in or from the Caribbean EEZ must be maintained with meat and shell intact. (b) The operator of a vessel that fishes in the EEZ is responsible for ensuring...

  15. Calcium Signaling in Intact Dorsal Root Ganglia

    PubMed Central

    Gemes, Geza; Rigaud, Marcel; Koopmeiners, Andrew S.; Poroli, Mark J.; Zoga, Vasiliki; Hogan, Quinn H.

    2013-01-01

    Background Ca2+ is the dominant second messenger in primary sensory neurons. In addition, disrupted Ca2+ signaling is a prominent feature in pain models involving peripheral nerve injury. Standard cytoplasmic Ca2+ recording techniques use high K+ or field stimulation and dissociated neurons. To compare findings in intact dorsal root ganglia, we used a method of simultaneous electrophysiologic and microfluorimetric recording. Methods Dissociated neurons were loaded by bath-applied Fura-2-AM and subjected to field stimulation. Alternatively, we adapted a technique in which neuronal somata of intact ganglia were loaded with Fura-2 through an intracellular microelectrode that provided simultaneous membrane potential recording during activation by action potentials (APs) conducted from attached dorsal roots. Results Field stimulation at levels necessary to activate neurons generated bath pH changes through electrolysis and failed to predictably drive neurons with AP trains. In the intact ganglion technique, single APs produced measurable Ca2+ transients that were fourfold larger in presumed nociceptive C-type neurons than in nonnociceptive Aβ-type neurons. Unitary Ca2+ transients summated during AP trains, forming transients with amplitudes that were highly dependent on stimulation frequency. Each neuron was tuned to a preferred frequency at which transient amplitude was maximal. Transients predominantly exhibited monoexponential recovery and had sustained plateaus during recovery only with trains of more than 100 APs. Nerve injury decreased Ca2+ transients in C-type neurons, but increased transients in Aβ-type neurons. Conclusions Refined observation of Ca2+ signaling is possible through natural activation by conducted APs in undissociated sensory neurons and reveals features distinct to neuronal types and injury state. PMID:20526180

  16. PRC2 Complexes with JARID2, MTF2, and esPRC2p48 in ES Cells to Modulate ES Cell Pluripotency and Somatic Cell Reprograming

    PubMed Central

    Zhang, Zhuo; Jones, Amanda; Sun, Chiao-Wang; Li, Chao; Chang, Chia-Wei; Joo, Heui-Yun; Dai, Qian; Mysliwiec, Matthew R.; Wu, Li-Chen; Guo, Yahong; Yang, Wei; Liu, Kaimao; Pawlik, Kevin M.; Erdjument-Bromage, Hediye; Tempst, Paul; Lee, Youngsook; Min, Jinrong; Townes, Tim M.; Wang, Hengbin

    2012-01-01

    Polycomb repressive complex two (PRC2) has been implicated in embryonic stem (ES) cell pluripotency; however, the mechanistic roles of this complex are unclear. It was assumed that ES cells contain PRC2 with the same subunit composition as that identified in HeLa cells and Drosophila embryos. Here, we report that PRC2 in mouse ES cells contains at least three additional subunits: JARID2, MTF2, and a novel protein denoted esPRC2p48. JARID2, MTF2, and esPRC2p48 are highly expressed in mouse ES cells compared to differentiated cells. Importantly, knockdowns of JARID2, MTF2, or esPRC2p48 alter the level of PRC2-mediated H3K27 methylation and result in the expression of differentiation-associated genes in ES cells. Interestingly, expression of JARID2, MTF2, and esPRC2p48 together, but not individually, enhances Oct4/Sox2/Klf4-mediated reprograming of mouse embryonic fibroblasts (MEFs) into induced pluripotent stem cells, whereas knockdown or knockout of JARID2, MTF2, or esPRC2p48 significantly inhibits reprograming. JARID2, MTF2, and esPRC2p48 modulate H3K27 methylation and facilitate repression of lineage-associated gene expression when transduced into MEFs, and synergistically stimulate the histone methyl-transferase activity of PRC2 in vitro. Therefore, these studies identify JARID2, MTF2, and esPRC2p48 as important regulatory subunits of PRC2 in ES cells and reveal critical functions of these subunits in modulating PRC2’s activity and gene expression both in ES cells and during somatic cell reprograming. PMID:21732481

  17. Cellular reprogramming through mitogen-activated protein kinases

    PubMed Central

    Lee, Justin; Eschen-Lippold, Lennart; Lassowskat, Ines; Böttcher, Christoph; Scheel, Dierk

    2015-01-01

    Mitogen-activated protein kinase (MAPK) cascades are conserved eukaryote signaling modules where MAPKs, as the final kinases in the cascade, phosphorylate protein substrates to regulate cellular processes. While some progress in the identification of MAPK substrates has been made in plants, the knowledge on the spectrum of substrates and their mechanistic action is still fragmentary. In this focused review, we discuss the biological implications of the data in our original paper (Sustained mitogen-activated protein kinase activation reprograms defense metabolism and phosphoprotein profile in Arabidopsis thaliana; Frontiers in Plant Science 5: 554) in the context of related research. In our work, we mimicked in vivo activation of two stress-activated MAPKs, MPK3 and MPK6, through transgenic manipulation of Arabidopsis thaliana and used phosphoproteomics analysis to identify potential novel MAPK substrates. Here, we plotted the identified putative MAPK substrates (and downstream phosphoproteins) as a global protein clustering network. Based on a highly stringent selection confidence level, the core networks highlighted a MAPK-induced cellular reprogramming at multiple levels of gene and protein expression—including transcriptional, post-transcriptional, translational, post-translational (such as protein modification, folding, and degradation) steps, and also protein re-compartmentalization. Additionally, the increase in putative substrates/phosphoproteins of energy metabolism and various secondary metabolite biosynthesis pathways coincides with the observed accumulation of defense antimicrobial substances as detected by metabolome analysis. Furthermore, detection of protein networks in phospholipid or redox elements suggests activation of downstream signaling events. Taken in context with other studies, MAPKs are key regulators that reprogram cellular events to orchestrate defense signaling in eukaryotes. PMID:26579181

  18. Epigenetic reprogramming that prevents transgenerational inheritance of the vernalized state.

    PubMed

    Crevillén, Pedro; Yang, Hongchun; Cui, Xia; Greeff, Christiaan; Trick, Martin; Qiu, Qi; Cao, Xiaofeng; Dean, Caroline

    2014-11-27

    The reprogramming of epigenetic states in gametes and embryos is essential for correct development in plants and mammals. In plants, the germ line arises from somatic tissues of the flower, necessitating the erasure of chromatin modifications that have accumulated at specific loci during development or in response to external stimuli. If this process occurs inefficiently, it can lead to epigenetic states being inherited from one generation to the next. However, in most cases, accumulated epigenetic modifications are efficiently erased before the next generation. An important example of epigenetic reprogramming in plants is the resetting of the expression of the floral repressor locus FLC in Arabidopsis thaliana. FLC is epigenetically silenced by prolonged cold in a process called vernalization. However, the locus is reactivated before the completion of seed development, ensuring the requirement for vernalization in every generation. In contrast to our detailed understanding of the polycomb-mediated epigenetic silencing induced by vernalization, little is known about the mechanism involved in the reactivation of FLC. Here we show that a hypomorphic mutation in the jumonji-domain-containing protein ELF6 impaired the reactivation of FLC in reproductive tissues, leading to the inheritance of a partially vernalized state. ELF6 has H3K27me3 demethylase activity, and the mutation reduced this enzymatic activity in planta. Consistent with this, in the next generation of mutant plants, H3K27me3 levels at the FLC locus stayed higher, and FLC expression remained lower, than in the wild type. Our data reveal an ancient role for H3K27 demethylation in the reprogramming of epigenetic states in plant and mammalian embryos.

  19. Sodium Absorption by Intact Sugar Beet Plants

    PubMed Central

    El-Sheikh, Adel M; Ulrich, Albert

    1971-01-01

    Sodium absorption by intact sugar beet plants (Beta vulgaris) was found to be mediated by at least two distinct mechanisms when uptake was studied over a wide range of Na and K concentrations. The first mechanism operates at low Na concentrations (<1 milliequivalent per liter); presence of K completely blocks this mechanism for Na. The second mechanism operates at high Na concentrations (>1 milliequivalent per liter), transporting Na as well as K; but apparently this mechanism is not active for Na absorption in young sugar beet plants up to the 10-leaf stage. PMID:16657872

  20. Reprogramming for Cardiac Regeneration-Strategies for Innovation.

    PubMed

    Sanchis-Gomar, Fabian; Galera, Teresa; Lucia, Alejandro; Gallardo, María Esther

    2016-09-01

    It is well-known that the human myocardium has a low capacity for self-regeneration. This fact is especially important after acute myocardial infarction with subsequent heart failure and adverse tissue remodeling. New potential strategies have recently emerged for treating heart diseases, such as the possibility of generating large quantities of cardiomyocytes through genetic iPSC reprogramming, transdifferentiation for in vitro disease modeling, in vivo therapies or telomerase gene reactivation. Approaches based on these techniques may represent the new horizon in cardiology with an appropriate 180-degree turn perspective. J. Cell. Physiol. 231: 1849-1851, 2016. © 2016 Wiley Periodicals, Inc.

  1. Aging, Rejuvenation, and Epigenetic Reprogramming: Resetting the Aging Clock

    PubMed Central

    Rando, Thomas A.; Chang, Howard Y.

    2012-01-01

    The underlying cause of aging remains one of the central mysteries of biology. Recent studies in several different systems suggest that not only may the rate of aging be modified by environmental and genetic factors, but also that the aging clock can be reversed, restoring characteristics of youthfulness to aged cells and tissues. This Review focuses on the emerging biology of rejuvenation through the lens of epigenetic reprogramming. By defining youthfulness and senescence as epigenetic states, a framework for asking new questions about the aging process emerges. PMID:22265401

  2. Reprogramming and transdifferentiation shift the landscape of regenerative medicine.

    PubMed

    Guo, Jingjing; Wang, Hu; Hu, Xingchang

    2013-10-01

    Regenerative medicine is a new interdisciplinary field in biomedical science, which aims at the repair or replacement of the defective tissue or organ by congenital defects, age, injury, or disease. Various cell-related techniques such as stem cell-based biotherapy are a hot topic in the current press, and stem cell research can help us to expand our understanding of development as well as the pathogenesis of disease. In addition, new technology such as reprogramming or dedifferentiation and transdifferentiation open a new area for regenerative medicine. Here we review new approaches of these technologies used for cell-based therapy and discuss future directions and challenges in the field of regeneration.

  3. Dedifferentiation, transdifferentiation, and reprogramming: future directions in regenerative medicine.

    PubMed

    Eguizabal, Cristina; Montserrat, Nuria; Veiga, Anna; Izpisua Belmonte, Juan Carlos

    2013-01-01

    The main goal of regenerative medicine is to replace damaged tissue. To do this it is necessary to understand in detail the whole regeneration process including differentiated cells that can be converted into progenitor cells (dedifferentiation), cells that can switch into another cell type (transdifferentiation), and somatic cells that can be induced to become pluripotent cells (reprogramming). By studying the regenerative processes in both nonmammal and mammal models, natural or artificial processes could underscore the molecular and cellular mechanisms behind these phenomena and be used to create future regenerative strategies for humans.

  4. Reprogramming of cassava (Manihot esculenta) microspores towards sporophytic development

    PubMed Central

    Perera, P. I. P.; Ordoñez, C. A.; Dedicova, B.; Ortega, P. E. M.

    2014-01-01

    Gametes have the unique potential to enter the sporophytic pathway, called androgenesis. The plants produced are usually haploid and recombinant due to the preceding meiosis and they can double their chromosome number to form doubled haploids, which are completely homozygous. Availability of the doubled haploids facilitates mapping the genes of agronomically important traits, shortening the time of the breeding process required to produce new hybrids and homozygous varieties, and saving the time and cost for inbreeding. This study aimed to test the feasibility of using isolated and in vitro cultured immature cassava (Manihot esculenta) microspores to reprogramme and initiate sporophytic development. Different culture media and different concentrations of two ion components (Cu2+ and Fe2+) were tested in two genotypes of cassava. External structural changes, nuclear divisions and cellular changes during reprogramming were analysed by scanning electron microscopy, by staining with 4′,6-diamidino-2-phenylindole, and through classical histology and transmission electron microscopy. In two cassava genotypes, different developmental stages of microspores were found to initiate sporophytic cell divisions, that is, with tetrads of TMS 60444 and with mid or late uni-nucleate microspores of SM 1219-9. In the modified NLN medium (NLNS), microspore enlargements were observed. The medium supplemented with either sodium ferrous ethylene-diamine-tetraacetic acid (NaFeEDTA) or CuSO4·5H2O induced sporophytic cell division in both genotypes. A low frequency of the reprogramming and the presence of non-responsive microspores among the responsive ones in tetrads were found to be related to the viability and exine formation of the microspores. The present study clearly demonstrated that reprogramming occurs much faster in isolated microspore culture than in anther culture. This paves the way for the development of an efficient technique for the production of homozygous lines in

  5. Hacker within! Ehrlichia chaffeensis Effector Driven Phagocyte Reprogramming Strategy

    PubMed Central

    Lina, Taslima T.; Farris, Tierra; Luo, Tian; Mitra, Shubhajit; Zhu, Bing; McBride, Jere W.

    2016-01-01

    Ehrlichia chaffeensis is a small, gram negative, obligately intracellular bacterium that preferentially infects mononuclear phagocytes. It is the etiologic agent of human monocytotropic ehrlichiosis (HME), an emerging life-threatening tick-borne zoonosis. Mechanisms by which E. chaffeensis establishes intracellular infection, and avoids host defenses are not well understood, but involve functionally relevant host-pathogen interactions associated with tandem and ankyrin repeat effector proteins. In this review, we discuss the recent advances in our understanding of the molecular and cellular mechanisms that underlie Ehrlichia host cellular reprogramming strategies that enable intracellular survival. PMID:27303657

  6. DEAD-Box RNA Binding Protein DDX5: Not a Black-Box during Reprogramming.

    PubMed

    Nefzger, Christian M; Polo, Jose M

    2017-04-06

    The role of RNA binding proteins (RBPs) during nuclear reprogramming is poorly characterized. In this issue of Cell Stem Cell,Li et al. (2017) show that DEAD-box RBP DDX5 acts as a reprogramming roadblock and give important mechanistic insights into the establishment of pluripotency by characterizing the intricate downstream events.

  7. SCNT versus iPSCs: proteins and small molecules in reprogramming.

    PubMed

    Han, Fei; Li, Xia; Song, Dandan; Jiang, Shaoshuai; Xu, Qun; Zhang, Yunhai

    2015-01-01

    Somatic cell nuclear transplantation (SCNT) and induced pluripotent stem cell (iPSC) technologies can be employed to change cell fate by reprogramming. The discoveries of SCNT and iPSCs were awarded the Nobel Prize for Physiology and Medicine in 2012, which reaffirmed the importance of cell fate plasticity. However, the low cloning efficiency of SCNT and differences between iPSCs and embryonic stem cells (ESCs) are great barriers and may be caused by incomplete or aberrant reprogramming. Additionally, the well characterized reprogramming factors Oct4, Sox2, Klf4 and c-Myc (OSKM) are not simultaneously expressed at high levels in enucleated or early embryonic oocytes, suggesting reprogramming may be different in the above two methods. Recent studies have demonstrated that small molecules and specific proteins expressed in oocytes and in early embryonic development play important roles in reprogramming by replacing transcription factors, erasing reprogramming memory and accelerating the speed and extent of reprogramming. In this review, we summarize the current state of SCNT and iPSCs technologies and discuss the latest advances in the research of proteins and small molecules affecting SCNT and iPSCs. This is an area of research in which chemical biology and proteomics are combining to facilitate improving cellular reprogramming and production of clinical grade iPSCs.

  8. A Lin28 homologue reprograms differentiated cells to stem cells in the moss Physcomitrella patens

    PubMed Central

    Li, Chen; Sako, Yusuke; Imai, Akihiro; Nishiyama, Tomoaki; Thompson, Kari; Kubo, Minoru; Hiwatashi, Yuji; Kabeya, Yukiko; Karlson, Dale; Wu, Shu-Hsing; Ishikawa, Masaki; Murata, Takashi; Benfey, Philip N.; Sato, Yoshikatsu; Tamada, Yosuke; Hasebe, Mitsuyasu

    2017-01-01

    Both land plants and metazoa have the capacity to reprogram differentiated cells to stem cells. Here we show that the moss Physcomitrella patens Cold-Shock Domain Protein 1 (PpCSP1) regulates reprogramming of differentiated leaf cells to chloronema apical stem cells and shares conserved domains with the induced pluripotent stem cell factor Lin28 in mammals. PpCSP1 accumulates in the reprogramming cells and is maintained throughout the reprogramming process and in the resultant stem cells. Expression of PpCSP1 is negatively regulated by its 3′-untranslated region (3′-UTR). Removal of the 3′-UTR stabilizes PpCSP1 transcripts, results in accumulation of PpCSP1 protein and enhances reprogramming. A quadruple deletion mutant of PpCSP1 and three closely related PpCSP genes exhibits attenuated reprogramming indicating that the PpCSP genes function redundantly in cellular reprogramming. Taken together, these data demonstrate a positive role of PpCSP1 in reprogramming, which is similar to the function of mammalian Lin28. PMID:28128346

  9. 7 CFR 160.29 - Containers to remain intact.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Containers to remain intact. 160.29 Section 160.29... STANDARDS FOR NAVAL STORES Analysis, Inspection, and Grading on Request § 160.29 Containers to remain intact... the containers holding such naval stores remain intact as sampled until the analysis,...

  10. Rapid isolation of intact chloroplasts from spinach leaves.

    PubMed

    Joly, David; Carpentier, Robert

    2011-01-01

    In this chapter, a rapid method to isolate intact chloroplasts from spinach leaves is described. Intact chloroplasts are isolated using two short centrifugation steps and avoiding the use of percoll gradient. Intactness of chloroplast is evaluated by the inability of potassium ferricyanide to enter inside the chloroplasts and to act as an electron acceptor for photosystem II.

  11. Reprogramming the pluripotent cell cycle: restoration of an abbreviated G1 phase in human induced pluripotent stem (iPS) cells

    PubMed Central

    Ghule, Prachi N.; Medina, Ricardo; Lengner, Chris J.; Mandeville, Matthew; Qiao, Meng; Dominski, Zbigniew; Lian, Jane B.; Stein, Janet L.; van Wijnen, Andre J.; Stein, Gary S.

    2011-01-01

    Induced pluripotent stem (iPS) cells derived from terminally differentiated human fibroblasts are re-programmed to possess stem cell like properties. However, the extent to which iPS cells exhibit unique properties of the human embryonic stem (hES) cell cycle remains to be established. Human ES cells are characterized by an abbreviated G1 phase (~2.5 h) and accelerated organization of subnuclear domains that mediate the assembly of regulatory machinery for histone gene expression [i.e., histone locus bodies (HLBs)]. We therefore examined cell cycle parameters of iPS cells in comparison to hES cells. Analysis of DNA synthesis (BrdU incorporation), cell cycle distribution (FACS analysis and Ki67 staining) and subnuclear organization of HLBs [immuno-fluorescence microscopy and fluorescence in situ hybridization (FISH)] revealed that human iPS cells have a short G1 phase (~2.5 h) and an abbreviated cell cycle (16–18 h). Furthermore, HLBs are formed and reorganized rapidly after mitosis (within0.5 to 1.5 h). Thus, reprogrammed iPS cells have cell cycle kinetics and dynamic subnuclear organization of regulatory machinery that are principal properties of pluripotent hES cells. Our findings support the concept that the abbreviated cell cycle of hES and iPS cells is functionally linked to pluripotency. PMID:20945438

  12. Genomic instability during reprogramming by nuclear transfer is DNA replication dependent.

    PubMed

    Chia, Gloryn; Agudo, Judith; Treff, Nathan; Sauer, Mark V; Billing, David; Brown, Brian D; Baer, Richard; Egli, Dieter

    2017-04-01

    Somatic cells can be reprogrammed to a pluripotent state by nuclear transfer into oocytes, yet developmental arrest often occurs. While incomplete transcriptional reprogramming is known to cause developmental failure, reprogramming also involves concurrent changes in cell cycle progression and nuclear structure. Here we study cellular reprogramming events in human and mouse nuclear transfer embryos prior to embryonic genome activation. We show that genetic instability marked by frequent chromosome segregation errors and DNA damage arise prior to, and independent of, transcriptional activity. These errors occur following transition through DNA replication and are repaired by BRCA1. In the absence of mitotic nuclear remodelling, DNA replication is delayed and errors are exacerbated in subsequent mitosis. These results demonstrate that independent of gene expression, cell-type-specific features of cell cycle progression constitute a barrier sufficient to prevent the transition from one cell type to another during reprogramming.

  13. Cocktail of chemical compounds robustly promoting cell reprogramming protects liver against acute injury.

    PubMed

    Tang, Yuewen; Cheng, Lin

    2017-02-11

    Tissue damage induces cells into reprogramming-like cellular state, which contributes to tissue regeneration. However, whether factors promoting the cell reprogramming favor tissue regeneration remains elusive. Here we identified combination of small chemical compounds including drug cocktails robustly promoting in vitro cell reprogramming. We then administrated the drug cocktails to mice with acute liver injuries induced by partial hepatectomy or toxic treatment. Our results demonstrated that the drug cocktails which promoted cell reprogramming in vitro improved liver regeneration and hepatic function in vivo after acute injuries. The underlying mechanism could be that expression of pluripotent genes activated after injury is further upregulated by drug cocktails. Thus our study offers proof-of-concept evidence that cocktail of clinical compounds improving cell reprogramming favors tissue recovery after acute damages, which is an attractive strategy for regenerative purpose.

  14. Recollections of Parent Characteristics and Attachment Patterns for College Women of Intact vs. Non-Intact Families

    ERIC Educational Resources Information Center

    Kilmann, Peter R.; Carranza, Laura V.; Vendemia, Jennifer M. C.

    2006-01-01

    This study contrasted offsprings' attachment patterns and recollections of parent characteristics in two college samples: 147 females from intact biological parents and 157 females of parental divorce. Secure females from intact or non-intact families rated parents positively, while insecure females rated parents as absent, distant, and demanding.…

  15. Generation and Characterization of Leukemia Inhibitory Factor-Dependent Equine Induced Pluripotent Stem Cells from Adult Dermal Fibroblasts

    PubMed Central

    Ovchinnikov, Dmitry A.; Sun, Jane; Fortuna, Patrick R.J.; Wolvetang, Ernst J.

    2014-01-01

    In this study we have reprogrammed dermal fibroblasts from an adult female horse into equine induced pluripotent stem cells (equiPSCs). These equiPSCs are dependent only on leukemia inhibitory factor (LIF), placing them in striking contrast to previously derived equiPSCs that have been shown to be co-dependent on both LIF and basic fibroblast growth factor (bFGF). These equiPSCs have a normal karyotype and have been maintained beyond 60 passages. They possess alkaline phosphatase activity and express eqNANOG, eqOCT4, and eqTERT mRNA. Immunocytochemistry confirmed that they produce NANOG, REX1, SSEA4, TRA1-60, and TRA1-81. While our equiPSCs are LIF dependent, bFGF co-stimulates their proliferation via the PI3K/AKT pathway. EquiPSCs lack expression of eqXIST and immunostaining for H3K27me3, suggesting that during reprogramming the inactive X chromosome has likely been reactivated to generate cells that have two active X chromosomes. EquiPSCs form embryoid bodies and in vitro teratomas that contain derivatives of all three germ layers. These LIF-dependent equiPSCs likely reflect a more naive state of pluripotency than equiPSCs that are co-dependent on both LIF and bFGF and so provide a novel resource for understanding pluripotency in the horse. PMID:24555755

  16. Stem cells and somatic cells: reprogramming and plasticity.

    PubMed

    Estrov, Zeev

    2009-01-01

    Recent seminal discoveries have significantly advanced the field of stem cell research and received worldwide attention. Improvements in somatic cell nuclear transfer (SCNT) technology, enabling the cloning of Dolly the sheep, and the derivation and differentiation of human embryonic stem cells raised hopes that normal cells could be generated to replace diseased or injured tissue. At the same time, in vitro and in vivo studies demonstrated that somatic cells of one tissue are capable of generating cells of another tissue. It was theorized that any cell might be reprogrammed, by exposure to a new environment, to become another cell type. This concept contradicts two established hypotheses: (1) that only specific tissues are generated from the endoderm, mesoderm, and ectoderm and (2) that tissue cells arise from a rare population of tissue-specific stem cells in a hierarchical fashion. SCNT, cell fusion experiments, and most recent gene transfer studies also contradict these hypotheses, as they demonstrate that mature somatic cells can be reprogrammed to regain pluripotent (or even totipotent) stem cell capacity. On the basis of the stem cell theory, hierarchical cancer stem cell differentiation models have been proposed. Cancer cell plasticity is an established phenomenon that supports the notion that cellular phenotype and function might be altered. Therefore, mechanisms of cellular plasticity should be exploited and the clinical significance of the cancer stem cell theory cautiously assessed.

  17. Reprogramming Human Endothelial to Hematopoietic Cells Requires Vascular Induction

    PubMed Central

    Sandler, Vladislav M.; Lis, Raphael; Liu, Ying; Kedem, Alon; James, Daylon; Elemento, Olivier; Butler, Jason M.; Scandura, Joseph M.; Rafii, Shahin

    2014-01-01

    Summary Generating engraftable human hematopoietic cells from autologous tissues promises new therapies for blood diseases. Directed differentiation of pluripotent stem cells yields hematopoietic cells that poorly engraft. Here, we devised a method to phenocopy the vascular-niche microenvironment of hemogenic cells, thereby enabling reprogramming of human endothelial cells (ECs) into engraftable hematopoietic cells without transition through a pluripotent intermediate. Highly purified non-hemogenic human umbilical vein-ECs (HUVECs) or adult dermal microvascular ECs (hDMECs) were transduced with transcription factors (TFs), FOSB, GFI1, RUNX1, and SPI1 (FGRS), and then propagated on serum-free instructive vascular niche monolayers to induce outgrowth of hematopoietic colonies containing cells with functional and immunophenotypic features of multipotent progenitor cells (MPP). These reprogrammed ECs- into human-MPPs (rEC-hMPPs) acquire colony-forming cell (CFC) potential and durably engraft in immune-deficient mice after primary and secondary transplantation, producing long-term rEC-hMPP-derived myeloid (granulocytic/monocytic, erythroid, megakaryocytic) and lymphoid (NK, B) progeny. Conditional expression of FGRS transgenes, combined with vascular-induction, activates endogenous FGRS genes endowing rEC-hMPPs with a transcriptional and functional profile similar to self-renewing MPPs. Our approach underscores the role of inductive cues from vascular-niche in orchestrating and sustaining hematopoietic specification and may prove useful for engineering autologous hematopoietic grafts to treat inherited and acquired blood disorders. PMID:25030167

  18. Therapeutic potential of targeting acinar cell reprogramming in pancreatic cancer.

    PubMed

    Wong, Chi-Hin; Li, You-Jia; Chen, Yang-Chao

    2016-08-21

    Pancreatic ductal adenocarcinoma (PDAC) is a common pancreatic cancer and the fourth leading cause of cancer death in the United States. Treating this life-threatening disease remains challenging due to the lack of effective prognosis, diagnosis and therapy. Apart from pancreatic duct cells, acinar cells may also be the origin of PDAC. During pancreatitis or combined with activating KRas(G12D) mutation, acinar cells lose their cellular identity and undergo a transdifferentiation process called acinar-to-ductal-metaplasia (ADM), forming duct cells which may then transform into pancreatic intraepithelial neoplasia (PanIN) and eventually PDAC. During ADM, the activation of mitogen-activated protein kinases, Wnt, Notch and phosphatidylinositide 3-kinases/Akt signaling inhibits the transcription of acinar-specific genes, including Mist and amylase, but promotes the expression of ductal genes, such as cytokeratin-19. Inhibition of this transdifferentiation process hinders the development of PanIN and PDAC. In addition, the transdifferentiated cells regain acinar identity, indicating ADM may be a reversible process. This provides a new therapeutic direction in treating PDAC through cancer reprogramming. Many studies have already demonstrated the success of switching PanIN/PDAC back to normal cells through the use of PD325901, the expression of E47, and the knockdown of Dickkopf-3. In this review, we discuss the signaling pathways involved in ADM and the therapeutic potential of targeting reprogramming in order to treat PDAC.

  19. Cell fate reprogramming by control of intracellular network dynamics

    NASA Astrophysics Data System (ADS)

    Zanudo, Jorge G. T.; Albert, Reka

    Identifying control strategies for biological networks is paramount for practical applications that involve reprogramming a cell's fate, such as disease therapeutics and stem cell reprogramming. Although the topic of controlling the dynamics of a system has a long history in control theory, most of this work is not directly applicable to intracellular networks. Here we present a network control method that integrates the structural and functional information available for intracellular networks to predict control targets. Formulated in a logical dynamic scheme, our control method takes advantage of certain function-dependent network components and their relation to steady states in order to identify control targets, which are guaranteed to drive any initial state to the target state with 100% effectiveness and need to be applied only transiently for the system to reach and stay in the desired state. We illustrate our method's potential to find intervention targets for cancer treatment and cell differentiation by applying it to a leukemia signaling network and to the network controlling the differentiation of T cells. We find that the predicted control targets are effective in a broad dynamic framework. Moreover, several of the predicted interventions are supported by experiments. This work was supported by NSF Grant PHY 1205840.

  20. Epigenomic Reprogramming of Adult Cardiomyocyte-Derived Cardiac Progenitor Cells

    PubMed Central

    Zhang, Yiqiang; Zhong, Jiang F; Qiu, Hongyu; Robb MacLellan, W.; Marbán, Eduardo; Wang, Charles

    2015-01-01

    It has been believed that mammalian adult cardiomyocytes (ACMs) are terminally-differentiated and are unable to proliferate. Recently, using a bi-transgenic ACM fate mapping mouse model and an in vitro culture system, we demonstrated that adult mouse cardiomyocytes were able to dedifferentiate into cardiac progenitor-like cells (CPCs). However, little is known about the molecular basis of their intrinsic cellular plasticity. Here we integrate single-cell transcriptome and whole-genome DNA methylation analyses to unravel the molecular mechanisms underlying the dedifferentiation and cell cycle reentry of mouse ACMs. Compared to parental cardiomyocytes, dedifferentiated mouse cardiomyocyte-derived CPCs (mCPCs) display epigenomic reprogramming with many differentially-methylated regions, both hypermethylated and hypomethylated, across the entire genome. Correlated well with the methylome, our transcriptomic data showed that the genes encoding cardiac structure and function proteins are remarkably down-regulated in mCPCs, while those for cell cycle, proliferation, and stemness are significantly up-regulated. In addition, implantation of mCPCs into infarcted mouse myocardium improves cardiac function with augmented left ventricular ejection fraction. Our study demonstrates that the cellular plasticity of mammalian cardiomyocytes is the result of a well-orchestrated epigenomic reprogramming and a subsequent global transcriptomic alteration. PMID:26657817

  1. Blood flow reprograms lymphatic vessels to blood vessels

    PubMed Central

    Chen, Chiu-Yu; Bertozzi, Cara; Zou, Zhiying; Yuan, Lijun; Lee, John S.; Lu, MinMin; Stachelek, Stan J.; Srinivasan, Sathish; Guo, Lili; Vincente, Andres; Mericko, Patricia; Levy, Robert J.; Makinen, Taija; Oliver, Guillermo; Kahn, Mark L.

    2012-01-01

    Human vascular malformations cause disease as a result of changes in blood flow and vascular hemodynamic forces. Although the genetic mutations that underlie the formation of many human vascular malformations are known, the extent to which abnormal blood flow can subsequently influence the vascular genetic program and natural history is not. Loss of the SH2 domain–containing leukocyte protein of 76 kDa (SLP76) resulted in a vascular malformation that directed blood flow through mesenteric lymphatic vessels after birth in mice. Mesenteric vessels in the position of the congenital lymphatic in mature Slp76-null mice lacked lymphatic identity and expressed a marker of blood vessel identity. Genetic lineage tracing demonstrated that this change in vessel identity was the result of lymphatic endothelial cell reprogramming rather than replacement by blood endothelial cells. Exposure of lymphatic vessels to blood in the absence of significant flow did not alter vessel identity in vivo, but lymphatic endothelial cells exposed to similar levels of shear stress ex vivo rapidly lost expression of PROX1, a lymphatic fate–specifying transcription factor. These findings reveal that blood flow can convert lymphatic vessels to blood vessels, demonstrating that hemodynamic forces may reprogram endothelial and vessel identity in cardiovascular diseases associated with abnormal flow. PMID:22622036

  2. X chromosome inactivation and epigenetic responses to cellular reprogramming.

    PubMed

    Lessing, Derek; Anguera, Montserrat C; Lee, Jeannie T

    2013-01-01

    Reprogramming somatic cells to derive induced pluripotent stem cells (iPSCs) has provided a new method to model disease and holds great promise for regenerative medicine. Although genetically identical to their donor somatic cells, iPSCs undergo substantial changes in the epigenetic landscape during reprogramming. One such epigenetic process, X chromosome inactivation (XCI), has recently been shown to vary widely in human female iPSCs and embryonic stem cells (ESCs). XCI is a form of dosage compensation whose chief regulator is the noncoding RNA Xist. In mouse iPSCs and ESCs, Xist expression and XCI strictly correlate with the pluripotent state, but no such correlation exists in humans. Lack of XIST expression in human cells is linked to reduced developmental potential and an altered transcriptional profile, including upregulation of genes associated with cancer, which has therefore led to concerns about the safety of pluripotent stem cells for use in regenerative medicine. In this review, we describe how different states of XIST expression define three classes of female human pluripotent stem cells and explore progress in discovering the reasons for these variations and how they might be countered.

  3. The Importance of Ubiquitination and Deubiquitination in Cellular Reprogramming

    PubMed Central

    Suresh, Bharathi; Lee, Junwon; Kim, Kye-Seong; Ramakrishna, Suresh

    2016-01-01

    Ubiquitination of core stem cell transcription factors can directly affect stem cell maintenance and differentiation. Ubiquitination and deubiquitination must occur in a timely and well-coordinated manner to regulate the protein turnover of several stemness related proteins, resulting in optimal embryonic stem cell maintenance and differentiation. There are two switches: an E3 ubiquitin ligase enzyme that tags ubiquitin molecules to the target proteins for proteolysis and a second enzyme, the deubiquitinating enzyme (DUBs), that performs the opposite action, thereby preventing proteolysis. In order to maintain stemness and to allow for efficient differentiation, both ubiquitination and deubiquitination molecular switches must operate properly in a balanced manner. In this review, we have summarized the importance of the ubiquitination of core stem cell transcription factors, such as Oct3/4, c-Myc, Sox2, Klf4, Nanog, and LIN28, during cellular reprogramming. Furthermore, we emphasize the role of DUBs in regulating core stem cell transcriptional factors and their function in stem cell maintenance and differentiation. We also discuss the possibility of using DUBs, along with core transcription factors, to efficiently generate induced pluripotent stem cells. Our review provides a relatively new understanding regarding the importance of ubiquitination/deubiquitination of stem cell transcription factors for efficient cellular reprogramming. PMID:26880980

  4. Roles of small molecules in somatic cell reprogramming.

    PubMed

    Su, Jian-bin; Pei, Duan-qing; Qin, Bao-ming

    2013-06-01

    The Nobel Prize in Physiology and Medicine 2012 was awarded to Sir John B GURDON and Shinya YAMANAKA for their discovery that mature cells can be reprogrammed to become pluripotent. This event reaffirms the importance of research on cell fate plasticity and the technology progress in the stem cell field and regenerative medicine. Indeed, reprogramming technology has developed at a dazzling speed within the past 6 years, yet we are still at the early stages of understanding the mechanisms of cell fate identity. This is particularly true in the case of human induced pluripotent stem cells (iPSCs), which lack reliable standards in the evaluation of their fidelity and safety prior to their application. Along with the genetic approaches, small molecules nowadays become convenient tools for modulating endogenous protein functions and regulating key cellular processes, including the mesenchymal-to-epithelial transition, metabolism, signal transduction and epigenetics. Moreover, small molecules may affect not only the efficiency of clone formation but also the quality of the resulting cells. With increasing availability of such chemicals, we can better understand the biology of stems cells and further improve the technology of generation of stem cells.

  5. Reprogramming metabolism by targeting sirtuin 6 attenuates retinal degeneration

    PubMed Central

    Zhang, Lijuan; Du, Jianhai; Justus, Sally; Hsu, Chun-Wei; Bonet-Ponce, Luis; Wu, Wen-Hsuan; Tsai, Yi-Ting; Wu, Wei-Pu; Jia, Yading; Duong, Jimmy K.; Mahajan, Vinit B.; Lin, Chyuan-Sheng; Wang, Shuang; Hurley, James B.

    2016-01-01

    Retinitis pigmentosa (RP) encompasses a diverse group of Mendelian disorders leading to progressive degeneration of rods and then cones. For reasons that remain unclear, diseased RP photoreceptors begin to deteriorate, eventually leading to cell death and, consequently, loss of vision. Here, we have hypothesized that RP associated with mutations in phosphodiesterase-6 (PDE6) provokes a metabolic aberration in rod cells that promotes the pathological consequences of elevated cGMP and Ca2+, which are induced by the Pde6 mutation. Inhibition of sirtuin 6 (SIRT6), a histone deacetylase repressor of glycolytic flux, reprogrammed rods into perpetual glycolysis, thereby driving the accumulation of biosynthetic intermediates, improving outer segment (OS) length, enhancing photoreceptor survival, and preserving vision. In mouse retinae lacking Sirt6, effectors of glycolytic flux were dramatically increased, leading to upregulation of key intermediates in glycolysis, TCA cycle, and glutaminolysis. Both transgenic and AAV2/8 gene therapy–mediated ablation of Sirt6 in rods provided electrophysiological and anatomic rescue of both rod and cone photoreceptors in a preclinical model of RP. Due to the extensive network of downstream effectors of Sirt6, this study motivates further research into the role that these pathways play in retinal degeneration. Because reprogramming metabolism by enhancing glycolysis is not gene specific, this strategy may be applicable to a wide range of neurodegenerative disorders. PMID:27841758

  6. ADAR1 promotes malignant progenitor reprogramming in chronic myeloid leukemia

    PubMed Central

    Jiang, Qingfei; Crews, Leslie A.; Barrett, Christian L.; Chun, Hye-Jung; Court, Angela C.; Isquith, Jane M.; Zipeto, Maria A.; Goff, Daniel J.; Minden, Mark; Sadarangani, Anil; Rusert, Jessica M.; Dao, Kim-Hien T.; Morris, Sheldon R.; Goldstein, Lawrence S. B.; Marra, Marco A.; Frazer, Kelly A.; Jamieson, Catriona H. M.

    2013-01-01

    The molecular etiology of human progenitor reprogramming into self-renewing leukemia stem cells (LSC) has remained elusive. Although DNA sequencing has uncovered spliceosome gene mutations that promote alternative splicing and portend leukemic transformation, isoform diversity also may be generated by RNA editing mediated by adenosine deaminase acting on RNA (ADAR) enzymes that regulate stem cell maintenance. In this study, whole-transcriptome sequencing of normal, chronic phase, and serially transplantable blast crisis chronic myeloid leukemia (CML) progenitors revealed increased IFN-γ pathway gene expression in concert with BCR-ABL amplification, enhanced expression of the IFN-responsive ADAR1 p150 isoform, and a propensity for increased adenosine-to-inosine RNA editing during CML progression. Lentiviral overexpression experiments demonstrate that ADAR1 p150 promotes expression of the myeloid transcription factor PU.1 and induces malignant reprogramming of myeloid progenitors. Moreover, enforced ADAR1 p150 expression was associated with production of a misspliced form of GSK3β implicated in LSC self-renewal. Finally, functional serial transplantation and shRNA studies demonstrate that ADAR1 knockdown impaired in vivo self-renewal capacity of blast crisis CML progenitors. Together these data provide a compelling rationale for developing ADAR1-based LSC detection and eradication strategies. PMID:23275297

  7. ADAR1 promotes malignant progenitor reprogramming in chronic myeloid leukemia.

    PubMed

    Jiang, Qingfei; Crews, Leslie A; Barrett, Christian L; Chun, Hye-Jung; Court, Angela C; Isquith, Jane M; Zipeto, Maria A; Goff, Daniel J; Minden, Mark; Sadarangani, Anil; Rusert, Jessica M; Dao, Kim-Hien T; Morris, Sheldon R; Goldstein, Lawrence S B; Marra, Marco A; Frazer, Kelly A; Jamieson, Catriona H M

    2013-01-15

    The molecular etiology of human progenitor reprogramming into self-renewing leukemia stem cells (LSC) has remained elusive. Although DNA sequencing has uncovered spliceosome gene mutations that promote alternative splicing and portend leukemic transformation, isoform diversity also may be generated by RNA editing mediated by adenosine deaminase acting on RNA (ADAR) enzymes that regulate stem cell maintenance. In this study, whole-transcriptome sequencing of normal, chronic phase, and serially transplantable blast crisis chronic myeloid leukemia (CML) progenitors revealed increased IFN-γ pathway gene expression in concert with BCR-ABL amplification, enhanced expression of the IFN-responsive ADAR1 p150 isoform, and a propensity for increased adenosine-to-inosine RNA editing during CML progression. Lentiviral overexpression experiments demonstrate that ADAR1 p150 promotes expression of the myeloid transcription factor PU.1 and induces malignant reprogramming of myeloid progenitors. Moreover, enforced ADAR1 p150 expression was associated with production of a misspliced form of GSK3β implicated in LSC self-renewal. Finally, functional serial transplantation and shRNA studies demonstrate that ADAR1 knockdown impaired in vivo self-renewal capacity of blast crisis CML progenitors. Together these data provide a compelling rationale for developing ADAR1-based LSC detection and eradication strategies.

  8. Oligodeoxynucleotide Probes for Detecting Intact Cells

    NASA Technical Reports Server (NTRS)

    Rosson, Reinhardt A.; Maurina-Brunker, Julie; Langley, Kim; Pynnonen, Christine M.

    2004-01-01

    A rapid, sensitive test using chemiluminescent oligodeoxynucleotide probes has been developed for detecting, identifying, and enumerating intact cells. The test is intended especially for use in detecting and enumerating bacteria and yeasts in potable water. As in related tests that have been developed recently for similar purposes, the oligodeoxynucleotide probes used in this test are typically targeted at either singlecopy deoxyribonucleic acid (DNA) genes (such as virulence genes) or the multiple copies (10,000 to 50,000 copies per cell) of 16S ribosomal ribonucleic acids (rRNAs). Some of those tests involve radioisotope or fluorescent labeling of the probes for reporting hybridization of probes to target nucleic acids. Others of those tests involve labeling with enzymes plus the use of chemiluminescent or chromogenic substrates to report hybridization via color or the emission of light, respectively. The present test is of the last-mentioned type. The chemiluminescence in the present test can be detected easily with relatively simple instrumentation. In developing the present test, the hybridization approach was chosen because hybridization techniques are very specific. Hybridization detects stable, inheritable genetic targets within microorganisms. These targets are not dependent on products of gene expression that can vary with growth conditions or physiological states of organisms in test samples. Therefore, unique probes can be designed to detect and identify specific genera or species of bacteria or yeast (in terms of rRNA target sequences) or can be designed to detect and identify virulence genes (genomic target sequences). Because of the inherent specificity of this system, there are few problems of cross-reactivity. Hybridization tests are rapid, but hybridization tests now available commercially lack sensitivity; typically, between 10(exp 6) and 10(exp 7) cells of the target organism are needed to ensure a reliable test. Consequently, the numbers of

  9. Heterochromatin reprogramming in rabbit embryos after fertilization, intra-, and inter-species SCNT correlates with preimplantation development.

    PubMed

    Yang, Cai-Xia; Liu, Zichuan; Fleurot, Renaud; Adenot, Pierre; Duranthon, Véronique; Vignon, Xavier; Zhou, Qi; Renard, Jean-Paul; Beaujean, Nathalie

    2013-02-01

    To investigate the embryonic genome organization upon fertilization and somatic cell nuclear transfer (SCNT), we tracked HP1β and CENP, two well-characterized protein markers of pericentric and centromeric compartments respectively, in four types of embryos produced by rabbit in vivo fertilization, rabbit parthenogenesis, rabbit-to-rabbit, and bovine-to-rabbit SCNT. In the interphase nuclei of rabbit cultured fibroblasts, centromeres and associated pericentric heterochromatin are usually isolated. Clustering into higher-order chromatin structures, such as the chromocenters seen in mouse and bovine somatic cells, could not be observed in rabbit fibroblasts. After fertilization, centromeres and associated pericentric heterochromatin are quite dispersed in rabbit embryos. The somatic-like organization is progressively established and completed only by the 8/16-cell stage, a stage that corresponds to major embryonic genome activation in this species. In SCNT embryos, pericentric heterochromatin distribution typical for rabbit and bovine somatic cells was incompletely reverted into the 1-cell embryonic form with remnants of heterochromatin clusters in 100% of bovine-to-rabbit embryos. Subsequently, the donor cell nuclear organization was rapidly re-established by the 4-cell stage. Remarkably, the incomplete remodeling of bovine-to-rabbit 1-cell embryos was associated with delayed transcriptional activation compared with rabbit-to-rabbit embryos. Together, the results confirm that pericentric heterochromatin spatio-temporal reorganization is an important step of embryonic genome reprogramming. It also appears that genome reorganization in SCNT embryos is mainly dependent on the nuclear characteristics of the donor cells, not on the recipient cytoplasm.

  10. Serum Fibroblast Growth Factor-23 Is Associated with Incident Kidney Disease

    PubMed Central

    Grams, Morgan E.; Coresh, Josef; Selvin, Elizabeth; Inker, Lesley A.; Levey, Andrew S.; Kimmel, Paul L.; Vasan, Ramachandran S.; Eckfeldt, John H.; Feldman, Harold I.; Hsu, Chi-yuan; Lutsey, Pamela L.

    2015-01-01

    Fibroblast growth factor-23 is a bone-derived hormone that increases urinary phosphate excretion and inhibits hydroxylation of 25-hydroxyvitamin D. Recent studies suggest that fibroblast growth factor-23 may be an early biomarker of CKD progression. However, its role in kidney function decline in the general population is unknown. We assessed the relationship between baseline (1990–1992) serum levels of intact fibroblast growth factor-23 and incident ESRD in 13,448 Atherosclerosis Risk in Communities study participants (56.1% women, 74.7% white) followed until December 31, 2010. At baseline, the mean age of participants was 56.9 years and the mean eGFR was 97 ml/min per 1.73 m2. During a median follow-up of 19 years, 267 participants (2.0%) developed ESRD. After adjustment for demographic characteristics, baseline eGFR, traditional CKD risk factors, and markers of mineral metabolism, the highest fibroblast growth factor-23 quintile (>54.6 pg/ml) compared with the lowest quintile (<32.0 pg/ml) was associated with risk of developing ESRD (hazard ratio, 2.10; 95% confidence interval, 1.31 to 3.36; trend P<0.001). In a large, community-based study comprising a broad range of kidney function, higher baseline fibroblast growth factor-23 levels were associated with increased risk of incident ESRD independent of the baseline level of kidney function and a number of other risk factors. PMID:25060052

  11. Fibroblasts drive an immunosuppressive and growth-promoting microenvironment in breast cancer via secretion of Chitinase 3-like 1.

    PubMed

    Cohen, N; Shani, O; Raz, Y; Sharon, Y; Hoffman, D; Abramovitz, L; Erez, N

    2017-04-03

    Cancer-Associated Fibroblasts (CAFs) are the most prominent stromal cell type in breast tumors. CAFs promote tumor growth and metastasis by multiple mechanisms, including by mediating tumor-promoting inflammation. Immune modulation in the tumor microenvironment plays a central role in determining disease outcome. However, the functional interactions of CAFs with immune cells are largely unknown. Here we report a novel signaling axis between fibroblasts, cancer cells and immune cells in breast tumors that drives an immunosuppressive microenvironment, mediated by CAF-derived Chi3L1. We demonstrate that Chi3L1 is highly upregulated in CAFs isolated from mammary tumors and pulmonary metastases of transgenic mice, and in the stroma of human breast carcinomas. Genetic ablation of Chi3L1 in fibroblasts in vivo attenuated tumor growth, macrophage recruitment and reprogramming to an M2-like phenotype, enhanced tumor infiltration by CD8(+) and CD4(+) T cells and promoted a Th1 phenotype. These results indicate that CAF-derived Chi3L1 promotes tumor growth and shifts the balance of the immune milieu towards type 2 immunity. Taken together, our findings implicate fibroblast-derived Chi3L1 as a novel key player in the complex reciprocal interactions of stromal cells that facilitate tumor progression and metastasis, and suggest that targeting Chi3L1 may be clinically beneficial in breast cancer.Oncogene advance online publication, 3 April 2017; doi:10.1038/onc.2017.65.

  12. Protein methylation reactions in intact pea chloroplasts

    SciTech Connect

    Niemi, K.J. )

    1989-04-01

    Post-translational protein methylation was investigated in Pisum sativum chloroplasts. Intact pea chloroplasts were incubated with ({sup 3}H-methyl)-S-adenosylmethionine under various conditions. The chloroplasts were then separated into stromal and thylakoid fractions and analyzed for radioactivity transferred to protein. Light enhanced the magnitude of labeling in both fractions. One thylakoid polypeptide with an apparent molecular mass of 43 kDa was labeled only in the light. Several other thylakoid and stromal proteins were labeled in both light and dark-labeling conditions. Both base-labile methylation, carboxy-methylesters and base-stable groups, N-methylations were found. Further characterization of the methyl-transfer reactions will be presented.

  13. Drilling to gabbro in intact ocean crust.

    PubMed

    Wilson, Douglas S; Teagle, Damon A H; Alt, Jeffrey C; Banerjee, Neil R; Umino, Susumu; Miyashita, Sumio; Acton, Gary D; Anma, Ryo; Barr, Samantha R; Belghoul, Akram; Carlut, Julie; Christie, David M; Coggon, Rosalind M; Cooper, Kari M; Cordier, Carole; Crispini, Laura; Durand, Sedelia Rodriguez; Einaudi, Florence; Galli, Laura; Gao, Yongjun; Geldmacher, Jörg; Gilbert, Lisa A; Hayman, Nicholas W; Herrero-Bervera, Emilio; Hirano, Nobuo; Holter, Sara; Ingle, Stephanie; Jiang, Shijun; Kalberkamp, Ulrich; Kerneklian, Marcie; Koepke, Jürgen; Laverne, Christine; Vasquez, Haroldo L Lledo; Maclennan, John; Morgan, Sally; Neo, Natsuki; Nichols, Holly J; Park, Sung-Hyun; Reichow, Marc K; Sakuyama, Tetsuya; Sano, Takashi; Sandwell, Rachel; Scheibner, Birgit; Smith-Duque, Chris E; Swift, Stephen A; Tartarotti, Paola; Tikku, Anahita A; Tominaga, Masako; Veloso, Eugenio A; Yamasaki, Toru; Yamazaki, Shusaku; Ziegler, Christa

    2006-05-19

    Sampling an intact sequence of oceanic crust through lavas, dikes, and gabbros is necessary to advance the understanding of the formation and evolution of crust formed at mid-ocean ridges, but it has been an elusive goal of scientific ocean drilling for decades. Recent drilling in the eastern Pacific Ocean in Hole 1256D reached gabbro within seismic layer 2, 1157 meters into crust formed at a superfast spreading rate. The gabbros are the crystallized melt lenses that formed beneath a mid-ocean ridge. The depth at which gabbro was reached confirms predictions extrapolated from seismic experiments at modern mid-ocean ridges: Melt lenses occur at shallower depths at faster spreading rates. The gabbros intrude metamorphosed sheeted dikes and have compositions similar to the overlying lavas, precluding formation of the cumulate lower oceanic crust from melt lenses so far penetrated by Hole 1256D.

  14. A review of induced pluripotent stem cell, direct conversion by trans-differentiation, direct reprogramming and oligodendrocyte differentiation.

    PubMed

    Prasad, Ankshita; Manivannan, Janani; Loong, Daniel T B; Chua, Soo M; Gharibani, Payam M; All, Angelo H

    2016-03-01

    Rapid progress in the field of stem cell therapy and cellular reprogramming provides convincing evidence of its feasibility in treating a wide range of pathologies through autologous cell replacement therapy. This review article describes in detail on three widely used approaches of somatic cell reprogramming: induced pluripotent stem cells, direct conversion and direct reprogramming, in the context of demyelination in the CNS. The potential limitations of each reprogramming technique are reviewed along with their distinct molecular approach to reprogramming. This is followed by an analysis on the scopes and challenges of its translational applications in deriving oligodendrocyte progenitor cells and oligodendrocytes for cell replacement treatment of demyelinating conditions in the CNS.

  15. Studying the Stoichiometry of Epidermal Growth Factor Receptor in Intact Cells using Correlative Microscopy.

    PubMed

    Peckys, Diana B; de Jonge, Niels

    2015-09-11

    This protocol describes the labeling of epidermal growth factor receptor (EGFR) on COS7 fibroblast cells, and subsequent correlative fluorescence microscopy and environmental scanning electron microscopy (ESEM) of whole cells in hydrated state. Fluorescent quantum dots (QDs) were coupled to EGFR via a two-step labeling protocol, providing an efficient and specific protein labeling, while avoiding label-induced clustering of the receptor. Fluorescence microscopy provided overview images of the cellular locations of the EGFR. The scanning transmission electron microscopy (STEM) detector was used to detect the QD labels with nanoscale resolution. The resulting correlative images provide data of the cellular EGFR distribution, and the stoichiometry at the single molecular level in the natural context of the hydrated intact cell. ESEM-STEM images revealed the receptor to be present as monomer, as homodimer, and in small clusters. Labeling with two different QDs, i.e., one emitting at 655 nm and at 800 revealed similar characteristic results.

  16. EpCAM Intracellular Domain Promotes Porcine Cell Reprogramming by Upregulation of Pluripotent Gene Expression via Beta-catenin Signaling

    PubMed Central

    Yu, Tong; Ma, Yangyang; Wang, Huayan

    2017-01-01

    Previous study showed that expression of epithelial cell adhesion molecule (EpCAM) was significantly upregulated in porcine induced pluripotent stem cells (piPSCs). However, the regulatory mechanism and the downstream target genes of EpCAM were not well investigated. In this study, we found that EpCAM was undetectable in fibroblasts, but highly expressed in piPSCs. Promoter of EpCAM was upregulated by zygotic activated factors LIN28, and ESRRB, but repressed by maternal factors OCT4 and SOX2. Knocking down EpCAM by shRNA significantly reduced the pluripotent gene expression. Conversely, overexpression of EpCAM significantly increased the number of alkaline phosphatase positive colonies and elevated the expression of endogenous pluripotent genes. As a key surface-to-nucleus factor, EpCAM releases its intercellular domain (EpICD) by a two-step proteolytic processing sequentially. Blocking the proteolytic processing by inhibitors TAPI-1 and DAPT could reduce the intracellular level of EpICD and lower expressions of OCT4, SOX2, LIN28, and ESRRB. We noticed that increasing intracellular EpICD only was unable to improve activity of EpCAM targeted genes, but by blocking GSK-3 signaling and stabilizing beta-catenin signaling, EpICD could then significantly stimulate the promoter activity. These results showed that EpCAM intracellular domain required beta-catenin signaling to enhance porcine cell reprogramming. PMID:28393933

  17. Reprogramming in vivo produces teratomas and iPS cells with totipotency features.

    PubMed

    Abad, María; Mosteiro, Lluc; Pantoja, Cristina; Cañamero, Marta; Rayon, Teresa; Ors, Inmaculada; Graña, Osvaldo; Megías, Diego; Domínguez, Orlando; Martínez, Dolores; Manzanares, Miguel; Ortega, Sagrario; Serrano, Manuel

    2013-10-17

    Reprogramming of adult cells to generate induced pluripotent stem cells (iPS cells) has opened new therapeutic opportunities; however, little is known about the possibility of in vivo reprogramming within tissues. Here we show that transitory induction of the four factors Oct4, Sox2, Klf4 and c-Myc in mice results in teratomas emerging from multiple organs, implying that full reprogramming can occur in vivo. Analyses of the stomach, intestine, pancreas and kidney reveal groups of dedifferentiated cells that express the pluripotency marker NANOG, indicative of in situ reprogramming. By bone marrow transplantation, we demonstrate that haematopoietic cells can also be reprogrammed in vivo. Notably, reprogrammable mice present circulating iPS cells in the blood and, at the transcriptome level, these in vivo generated iPS cells are closer to embryonic stem cells (ES cells) than standard in vitro generated iPS cells. Moreover, in vivo iPS cells efficiently contribute to the trophectoderm lineage, suggesting that they achieve a more plastic or primitive state than ES cells. Finally, intraperitoneal injection of in vivo iPS cells generates embryo-like structures that express embryonic and extraembryonic markers. We conclude that reprogramming in vivo is feasible and confers totipotency features absent in standard iPS or ES cells. These discoveries could be relevant for future applications of reprogramming in regenerative medicine.

  18. Early ERK1/2 activation promotes DRP1-dependent mitochondrial fission necessary for cell reprogramming.

    PubMed

    Prieto, Javier; León, Marian; Ponsoda, Xavier; Sendra, Ramón; Bort, Roque; Ferrer-Lorente, Raquel; Raya, Angel; López-García, Carlos; Torres, Josema

    2016-03-31

    During the process of reprogramming to induced pluripotent stem (iPS) cells, somatic cells switch from oxidative to glycolytic metabolism, a transition associated with profound mitochondrial reorganization. Neither the importance of mitochondrial remodelling for cell reprogramming, nor the molecular mechanisms controlling this process are well understood. Here, we show that an early wave of mitochondrial fragmentation occurs upon expression of reprogramming factors. Reprogramming-induced mitochondrial fission is associated with a minor decrease in mitochondrial mass but not with mitophagy. The pro-fission factor Drp1 is phosphorylated early in reprogramming, and its knockdown and inhibition impairs both mitochondrial fragmentation and generation of iPS cell colonies. Drp1 phosphorylation depends on Erk activation in early reprogramming, which occurs, at least in part, due to downregulation of the MAP kinase phosphatase Dusp6. Taken together, our data indicate that mitochondrial fission controlled by an Erk-Drp1 axis constitutes an early and necessary step in the reprogramming process to pluripotency.

  19. Early ERK1/2 activation promotes DRP1-dependent mitochondrial fission necessary for cell reprogramming

    PubMed Central

    Prieto, Javier; León, Marian; Ponsoda, Xavier; Sendra, Ramón; Bort, Roque; Ferrer-Lorente, Raquel; Raya, Angel; López-García, Carlos; Torres, Josema

    2016-01-01

    During the process of reprogramming to induced pluripotent stem (iPS) cells, somatic cells switch from oxidative to glycolytic metabolism, a transition associated with profound mitochondrial reorganization. Neither the importance of mitochondrial remodelling for cell reprogramming, nor the molecular mechanisms controlling this process are well understood. Here, we show that an early wave of mitochondrial fragmentation occurs upon expression of reprogramming factors. Reprogramming-induced mitochondrial fission is associated with a minor decrease in mitochondrial mass but not with mitophagy. The pro-fission factor Drp1 is phosphorylated early in reprogramming, and its knockdown and inhibition impairs both mitochondrial fragmentation and generation of iPS cell colonies. Drp1 phosphorylation depends on Erk activation in early reprogramming, which occurs, at least in part, due to downregulation of the MAP kinase phosphatase Dusp6. Taken together, our data indicate that mitochondrial fission controlled by an Erk-Drp1 axis constitutes an early and necessary step in the reprogramming process to pluripotency. PMID:27030341

  20. Plasticity of Adult Human Pancreatic Duct Cells by Neurogenin3-Mediated Reprogramming

    PubMed Central

    Bonné, Stefan; Heremans, Yves; Borup, Rehannah; Van de Casteele, Mark; Ling, Zhidong; Pipeleers, Daniel; Ravassard, Philippe; Nielsen, Finn; Ferrer, Jorge; Heimberg, Harry

    2012-01-01

    Aims/Hypothesis Duct cells isolated from adult human pancreas can be reprogrammed to express islet beta cell genes by adenoviral transduction of the developmental transcription factor neurogenin3 (Ngn3). In this study we aimed to fully characterize the extent of this reprogramming and intended to improve it. Methods The extent of the Ngn3-mediated duct-to-endocrine cell reprogramming was measured employing genome wide mRNA profiling. By modulation of the Delta-Notch signaling or addition of pancreatic endocrine transcription factors Myt1, MafA and Pdx1 we intended to improve the reprogramming. Results Ngn3 stimulates duct cells to express a focused set of genes that are characteristic for islet endocrine cells and/or neural tissues. This neuro-endocrine shift however, is incomplete with less than 10% of full duct-to-endocrine reprogramming achieved. Transduction of exogenous Ngn3 activates endogenous Ngn3 suggesting auto-activation of this gene. Furthermore, pancreatic endocrine reprogramming of human duct cells can be moderately enhanced by inhibition of Delta-Notch signaling as well as by co-expressing the transcription factor Myt1, but not MafA and Pdx1. Conclusions/Interpretation The results provide further insight into the plasticity of adult human duct cells and suggest measurable routes to enhance Ngn3-mediated in vitro reprogramming protocols for regenerative beta cell therapy in diabetes. PMID:22606327

  1. Single cell transcriptome analysis reveals dynamic changes in lncRNA expression during reprogramming

    PubMed Central

    Kim, Daniel H.; Marinov, Georgi K.; Pepke, Shirley; Singer, Zakary S.; He, Peng; Williams, Brian; Schroth, Gary P.; Elowitz, Michael B.; Wold, Barbara J.

    2014-01-01

    SUMMARY Cellular reprogramming highlights the epigenetic plasticity of the somatic cell state. Long noncoding RNAs (lncRNAs) have emerging roles in epigenetic regulation, but their potential functions in reprogramming cell fate have been largely unexplored. We used single-cell RNA sequencing to characterize the expression patterns of over 16,000 genes, including 437 lncRNAs, during defined stages of reprogramming to pluripotency. Self-organizing maps (SOMs) were used as an intuitive way to structure and interrogate transcriptome data at the single-cell level. Early molecular events during reprogramming involved the activation of Ras signaling pathways, along with hundreds of lncRNAs. Loss-of-function studies showed that activated lncRNAs can repress lineage-specific genes, while lncRNAs activated in multiple reprogramming cell types can regulate metabolic gene expression. Our findings demonstrate that reprogramming cells activate defined sets of functionally relevant lncRNAs and provide a resource to further investigate how dynamic changes in the transcriptome reprogram cell state. PMID:25575081

  2. LRRK2 Expression Is Deregulated in Fibroblasts and Neurons from Parkinson Patients with Mutations in PINK1.

    PubMed

    Azkona, Garikoitz; López de Maturana, Rakel; Del Rio, Patricia; Sousa, Amaya; Vazquez, Nerea; Zubiarrain, Amaia; Jimenez-Blasco, Daniel; Bolaños, Juan P; Morales, Blas; Auburger, Georg; Arbelo, José Matias; Sánchez-Pernaute, Rosario

    2016-12-14

    Mutations in PINK1 (PARK6), a serine/threonine kinase involved in mitochondrial homeostasis, are associated with early onset Parkinson's disease. Fibroblasts from Parkinson's disease patients with compound heterozygous mutations in exon 7 (c.1488 + 1G > A; c.1252_1488del) showed no apparent signs of mitochondrial impairment. To elucidate changes primarily caused by lack of functional PINK1, we over-expressed wild-type PINK1, which induced a significant downregulation of LRRK2 (PARK8). Indeed, we found that LRRK2 protein basal levels were significantly higher in the mutant PINK1 fibroblasts. To examine the interaction between the two PARK genes in a disease-relevant cell context, we generated induced pluripotent stem cell (iPSC) lines from mutant, carrier and control fibroblasts by lentiviral-mediated re-programming. Efficiency of neural induction and dopamine differentiation using a floor-plate induction protocol was similar in all genotypes. As observed in fibroblasts, PINK1 mutant neurons showed increased LRRK2 expression both at the RNA and protein level and transient over-expression of wild-type PINK1 efficiently downregulated LRRK2 levels. Additionally, we confirmed a dysregulation of LRRK2 expression in fibroblasts from patients with a different homozygous mutation in PINK1 exon 4, c.926G > A (G309D). Thus, our results identify a novel role of PINK1 modulating the levels of LRRK2 in Parkinson's disease fibroblasts and neurons, suggest a convergent pathway for these PARK genes, and broaden the role of LRRK2 in the pathogenesis of Parkinson's disease.

  3. Therapeutic transdifferentiation of human fibroblasts into endothelial cells using forced expression of lineage-specific transcription factors.

    PubMed

    Wong, Wing Tak; Cooke, John P

    2016-01-01

    Transdifferentiation is the direct conversion from one somatic cell type into another desired somatic cell type. This reprogramming method offers an attractive approach for regenerative medicine. Here, we demonstrate that neonatal fibroblasts can be transdifferentiated into endothelial cells using only four endothelial transcription factors, namely, ETV2, FLI1, GATA2, and KLF4. We observed a significant up-regulation of endothelial genes including KDR, CD31, CD144, and vWF in human neonatal foreskin (BJ) fibroblasts infected with the lentiviral construct encoding the open reading frame of the four transcription factors. We observed morphological changes in BJ fibroblasts from the fibroblastic spindle shape into a more endothelial-like cobblestone structures. Fluorescence-activated cell sorting analysis revealed that ~16% of the infected cells with the lentiviral constructs encoding 4F expressed CD31. The sorted cells were allowed to expand for 2 weeks and these cells were immunostained and found to express endothelial markers CD31. The induced endothelial cells also incorporated fluorescence-labeled acetylated low-density lipoprotein and efficiently formed capillary-like networks when seeded on Matrigel. These results suggested that the induced endothelial cells were functional in vitro. Taken together, we successfully demonstrated the direct conversion of human neonatal fibroblasts into endothelial cells by transduction of lentiviral constructs encoding endothelial lineage-specific transcription factors ETV2, FLI1, GATA2, and KLF4. The directed differentiation of fibroblasts into endothelial cells may have significant utility in diseases characterized by fibrosis and loss of microvasculature.

  4. Epigenomic Regulation of Schwann Cell Reprogramming in Peripheral Nerve Injury

    PubMed Central

    Ma, Ki H.; Hung, Holly A.

    2016-01-01

    The rapid and dynamic transcriptional changes of Schwann cells in response to injury are critical to peripheral nerve repair, yet the epigenomic reprograming that leads to the induction of injury-activated genes has not been characterized. Polycomb Repressive Complex 2 (PRC2) catalyzes the trimethylation of lysine 27 of histone H3 (H3K27me3), which produces a transcriptionally repressive chromatin environment. We find that many promoters and/or gene bodies of injury-activated genes of mature rat nerves are occupied with H3K27me3. In contrast, the majority of distal enhancers that gain H3K27 acetylation after injury are not repressed by H3K27 methylation before injury, which is normally observed in developmentally poised enhancers. Injury induces demethylation of H3K27 in many genes, such as Sonic hedgehog (Shh), which is silenced throughout Schwann cell development before injury. In addition, experiments using a Schwann cell-specific mouse knock-out of the Eed subunit of PRC2 indicate that demethylation is a rate-limiting step in the activation of such genes. We also show that some transcription start sites of H3K27me3-repressed injury genes of uninjured nerves are bound with a mark of active promoters H3K4me3, for example, Shh and Gdnf, and the reduction of H3K27me3 results in increased trimethylation of H3K4. Our findings identify reversal of polycomb repression as a key step in gene activation after injury. SIGNIFICANCE STATEMENT Peripheral nerve regeneration after injury is dependent upon implementation of a novel genetic program in Schwann cells that supports axonal survival and regeneration. Identifying means to enhance Schwann cell reprogramming after nerve injury could be used to foster effective remyelination in the treatment of demyelinating disorders and in identifying pathways involved in regenerative process of myelination. Although recent progress has identified transcriptional determinants of successful reprogramming of the Schwann cell transcriptome

  5. Therapy-induced developmental reprogramming of prostate cancer cells and acquired therapy resistance.

    PubMed

    Nouri, Mannan; Caradec, Josselin; Lubik, Amy Anne; Li, Na; Hollier, Brett G; Takhar, Mandeep; Altimirano-Dimas, Manuel; Chen, Mengqian; Roshan-Moniri, Mani; Butler, Miriam; Lehman, Melanie; Bishop, Jennifer; Truong, Sarah; Huang, Shih-Chieh; Cochrane, Dawn; Cox, Michael; Collins, Colin; Gleave, Martin; Erho, Nicholas; Alshalafa, Mohamed; Davicioni, Elai; Nelson, Colleen; Gregory-Evans, Sheryl; Karnes, R Jeffrey; Jenkins, Robert B; Klein, Eric A; Buttyan, Ralph

    2017-01-27

    Treatment-induced neuroendocrine transdifferentiation (NEtD) complicates therapies for metastatic prostate cancer (PCa). Based on evidence that PCa cells can transdifferentiate to other neuroectodermally-derived cell lineages in vitro, we proposed that NEtD requires first an intermediary reprogramming to metastable cancer stem-like cells (CSCs) of a neural class and we demonstrate that several different AR+/PSA+ PCa cell lines were efficiently reprogrammed to, maintained and propagated as CSCs by growth in androgen-free neural/neural crest (N/NC) stem medium. Such reprogrammed cells lost features of prostate differentiation; gained features of N/NC stem cells and tumor-initiating potential; were resistant to androgen signaling inhibition; and acquired an invasive phenotype in vitro and in vivo. When placed back into serum-containing mediums, reprogrammed cells could be re-differentiated to N-/NC-derived cell lineages or return back to an AR+ prostate-like state. Once returned, the AR+ cells were resistant to androgen signaling inhibition. Acute androgen deprivation or anti-androgen treatment in serum-containing medium led to the transient appearance of a sub-population of cells with similar characteristics. Finally, a 132 gene signature derived from reprogrammed PCa cell lines distinguished tumors from PCa patients with adverse outcomes. This model may explain neural manifestations of PCa associated with lethal disease. The metastable nature of the reprogrammed stem-like PCa cells suggests that cycles of PCa cell reprogramming followed by re-differentiation may support disease progression and therapeutic resistance. The ability of a gene signature from reprogrammed PCa cells to identify tumors from patients with metastasis or PCa-specific mortality implies that developmental reprogramming is linked to aggressive tumor behaviors.

  6. Connexin43 contributes to electrotonic conduction across scar tissue in the intact heart

    NASA Astrophysics Data System (ADS)

    Mahoney, Vanessa M.; Mezzano, Valeria; Mirams, Gary R.; Maass, Karen; Li, Zhen; Cerrone, Marina; Vasquez, Carolina; Bapat, Aneesh; Delmar, Mario; Morley, Gregory E.

    2016-05-01

    Studies have demonstrated non-myocytes, including fibroblasts, can electrically couple to myocytes in culture. However, evidence demonstrating current can passively spread across scar tissue in the intact heart remains elusive. We hypothesize electrotonic conduction occurs across non-myocyte gaps in the heart and is partly mediated by Connexin43 (Cx43). We investigated whether non-myocytes in ventricular scar tissue are electrically connected to surrounding myocardial tissue in wild type and fibroblast-specific protein-1 driven conditional Cx43 knock-out mice (Cx43fsp1KO). Electrical coupling between the scar and uninjured myocardium was demonstrated by injecting current into the myocardium and recording depolarization in the scar through optical mapping. Coupling was significantly reduced in Cx43fsp1KO hearts. Voltage signals were recorded using microelectrodes from control scars but no signals were obtained from Cx43fsp1KO hearts. Recordings showed significantly decreased amplitude, depolarized resting membrane potential, increased duration and reduced upstroke velocity compared to surrounding myocytes, suggesting that the non-excitable cells in the scar closely follow myocyte action potentials. These results were further validated by mathematical simulations. Optical mapping demonstrated that current delivered within the scar could induce activation of the surrounding myocardium. These data demonstrate non-myocytes in the scar are electrically coupled to myocytes, and coupling depends on Cx43 expression.

  7. Reprogramming cellular behavior with RNA controllers responsive to endogenous proteins.

    PubMed

    Culler, Stephanie J; Hoff, Kevin G; Smolke, Christina D

    2010-11-26

    Synthetic genetic devices that interface with native cellular pathways can be used to change natural networks to implement new forms of control and behavior. The engineering of gene networks has been limited by an inability to interface with native components. We describe a class of RNA control devices that overcome these limitations by coupling increased abundance of particular proteins to targeted gene expression events through the regulation of alternative RNA splicing. We engineered RNA devices that detect signaling through the nuclear factor κB and Wnt signaling pathways in human cells and rewire these pathways to produce new behaviors, thereby linking disease markers to noninvasive sensing and reprogrammed cellular fates. Our work provides a genetic platform that can build programmable sensing-actuation devices enabling autonomous control over cellular behavior.

  8. Cellular Reprogramming Using Protein and Cell-Penetrating Peptides

    PubMed Central

    Seo, Bong Jong; Hong, Yean Ju; Do, Jeong Tae

    2017-01-01

    Recently, stem cells have been suggested as invaluable tools for cell therapy because of their self-renewal and multilineage differentiation potential. Thus, scientists have developed a variety of methods to generate pluripotent stem cells, from nuclear transfer technology to direct reprogramming using defined factors, or induced pluripotent stem cells (iPSCs). Considering the ethical issues and efficiency, iPSCs are thought to be one of the most promising stem cells for cell therapy. Induced pluripotent stem cells can be generated by transduction with a virus, plasmid, RNA, or protein. Herein, we provide an overview of the current technology for iPSC generation and describe protein-based transduction technology in detail. PMID:28273812

  9. Nuclear Reprogramming by Defined Factors: Quantity Versus Quality.

    PubMed

    Sebban, Shulamit; Buganim, Yosef

    2016-01-01

    The generation of induced pluripotent stem cells (iPSCs) and directly converted cells holds great promise in regenerative medicine. However, after in-depth studies of the murine system, we know that the current methodologies to produce these cells are not ideal and mostly yield cells of poor quality that might hold a risk in therapeutic applications. In this review we address the duality found in the literature regarding the use of 'quality' as a criterion for the clinic. We discuss the elements that influence reprogramming quality, and provide evidence that safety and functionality are directly linked to cell quality. Finally, because most of the available data come from murine systems, we speculate about what aspects can be applied to human cells.

  10. Delivering factors for reprogramming a somatic cell to pluripotency.

    PubMed

    Um, Soong Ho

    2012-05-01

    An adult cell originates from stem cell. The stem cell is usually categorized into three species including an embryonic stem cell (ESc), an adult stem cell, and an induced stem cell (iPSc). iPSc features pluripotency, which is meant to be differentiated into any types of cells. Accordingly, it is much attractive to anyone who pursuit a regenerative medicine, owing to the potential almighty. They are simply produced by reprogramming a somatic cell via a transfer of transcription factors. The efficiency and productivity of iPS are considerably subject to delivering methods of exogenous genes into a variety of targeted mammalians. Conventional and well-run gene delivery techniques have been reviewed here. This details the methods and principles of delivery factors and provides an overview of the research, with an emphasis on their potential for use as clinical therapeutic platforms.

  11. Concise review: Human cell engineering: cellular reprogramming and genome editing.

    PubMed

    Mali, Prashant; Cheng, Linzhao

    2012-01-01

    Cell engineering is defined here as the collective ability to both reset and edit the genome of a mammalian cell. Until recently, this had been extremely challenging to achieve as nontransformed human cells are significantly refractory to both these processes. The recent success in reprogramming somatic cells into induced pluripotent stem cells that are self-renewable in culture, coupled with our increasing ability to effect precise and predesigned genomic editing, now readily permits cellular changes at both the genetic and epigenetic levels. These dual capabilities also make possible the generation of genetically matched, disease-free stem cells from patients for regenerative medicine. The objective of this review is to summarize the key enabling developments on these two rapidly evolving research fronts in human cell engineering, highlight unresolved issues, and outline potential future research directions.

  12. Polarization and reprogramming of myeloid-derived suppressor cells.

    PubMed

    Yang, Wen-Chin; Ma, Ge; Chen, Shu-Hsia; Pan, Ping-Ying

    2013-06-01

    Myeloid-derived suppressor cells (MDSC) have recently emerged as one of the central regulators of the immune system. In recent years, interest in understanding MDSC biology and applying MDSC for therapeutic purpose has exploded exponentially. Despite recent progress in MDSC biology, the mechanisms underlying MDSC development from expansion and activation to polarization in different diseases remain poorly understood. More recent studies have demonstrated that two MDSC subsets, M (monocytic)-MDSC and G (granulocytic)-MDSC, are able to polarize from a classically activated phenotype (M1) to an alternatively activated one (M2), or vice versa, in tumor-bearing mice. This phenotypic polarization affects MDSC function and disease progression. In this article, we summarize and discuss polarization, mechanism and therapeutic potential of MDSC. An emphasis is placed on the emerging concept of reprogramming MDSC polarization as a therapeutic strategy.

  13. Brain repair and reprogramming: the route to clinical translation.

    PubMed

    Grealish, S; Drouin-Ouellet, J; Parmar, M

    2016-09-01

    The adult brain has a very limited capacity for generation of new neurons, and neurogenesis only takes place in restricted regions. Some evidence for neurogenesis after injury has been reported, but few, if any, neurons are replaced after brain injury or degeneration, and the permanent loss of neurons leads to long-term disability and loss of brain function. For decades, researchers have been developing cell transplantation using exogenous cell sources for brain repair, and this method has now been shown to successfully restore lost function in experimental and clinical trials. Here, we review the development of cell-replacement strategies for brain repair in Parkinson's disease using the example of human foetal brain cells being successfully translated from preclinical findings to clinical trials. These trials demonstrate that cell-replacement therapy is a viable option for patients with Parkinson's disease, but more importantly also show how the limited availability of foetal cells calls for development of novel cell sources and methods for generating new neurons for brain repair. We focus on new stem cell sources that are on the threshold of clinical application for brain repair and discuss emerging cellular reprogramming technologies. Reviewing the current status of direct neural conversion, both in vitro and in vivo, where somatic cells are directly reprogrammed into functional neurons without passing through a stem cell intermediate, we conclude that both methods result in the successful replacement of new neurons that mature and integrate into the host brain. Thus, this new field shows great promise for future brain repair, although much work is still needed in preclinical animal models before it can be seriously considered for clinical applications.

  14. Molecular Pathways: Mitochondrial Reprogramming in Tumor Progression and Therapy

    PubMed Central

    Caino, M. Cecilia; Altieri, Dario C.

    2015-01-01

    Small molecule inhibitors of the phosphatidylinositol 3-kinase (PI3K), Akt and mTOR pathway currently in the clinic produce a paradoxical reactivation of the pathway they are intended to suppress. Furthermore, fresh experimental evidence with PI3K antagonists in melanoma, glioblastoma and prostate cancer shows that mitochondrial metabolism drives an elaborate process of tumor adaptation culminating with drug resistance and metastatic competency. This is centered on reprogramming of mitochondrial functions to promote improved cell survival and to fuel the machinery of cell motility and invasion. Key players in these responses are molecular chaperones of the Heat Shock Protein 90 (Hsp90) family compartmentalized in mitochondria, which suppress apoptosis via phosphorylation of the pore component, Cyclophilin D, and enable the subcellular repositioning of active mitochondria to membrane protrusions implicated in cell motility. An inhibitor of mitochondrial Hsp90s in preclinical development (Gamitrinib) prevents adaptive mitochondrial reprogramming and shows potent anti-tumor activity in vitro and in vivo. Other therapeutic strategies to target mitochondria for cancer therapy include small molecule inhibitors of mutant isocitrate dehydrogenase (IDH) IDH1 (AG-120) and IDH2 (AG-221) which opened new therapeutic prospects for high-risk AML patients. A second approach of mitochondrial therapeutics focuses on agents that elevate toxic ROS levels from a leaky electron transport chain, nevertheless the clinical experience with these compounds, including a quinone derivative, ARQ 501, and a copper chelator, elesclomol (STA-4783) is limited. In light of these evidences, we discuss how best to target a resurgence of mitochondrial bioenergetics for cancer therapy. PMID:26660517

  15. Characteristics of stem cells from human exfoliated deciduous teeth (SHED) from intact cryopreserved deciduous teeth.

    PubMed

    Lee, Hyo-Seol; Jeon, Mijeong; Jeon, Mi Jung; Kim, Seong-Oh; Kim, Seung-Hye; Lee, Jae-Ho; Lee, Jea-Ho; Ahn, Su-Jin; Shin, Yooseok; Song, Je Seon

    2015-12-01

    The aim of this study is to compare the characteristics of stem cells derived from human exfoliated deciduous teeth (SHED) from cryopreserved intact deciduous teeth with those of fresh SHED. In total, 20 exfoliated deciduous teeth were randomly divided into a fresh group (f-SHED; n = 11) and cryopreserved group (c-SHED; n = 9; stored for 1-8 months). Following thawing and separation of the pulp, the SHED cells were cultured, and the characteristics as mesenchymal stem cells were investigated using proliferation assays, cell-cycle analysis, colony-forming unit-fibroblast (CFU-F) assays, and flow cytometry analyses. Furthermore, differentiation into adipogenic and osteogenic lineages was investigated in vitro as well as in vivo via transplantation in mice. We found no significant differences between the two groups in the proliferation analyses, in the expression of mesenchymal stem cell markers, or in the adipogenic and osteogenic differentiation in vitro (p < 0.05). Furthermore, the in vivo transplantation results showed no significant differences in the quantity of bone tissue that formed or in histochemistry performance (p < 0.05). In conclusion, cryopreservation of intact exfoliated deciduous teeth appears to be a useful method for preserving SHED.

  16. Uranium migration through intact sandstone cores

    NASA Astrophysics Data System (ADS)

    Read, D.; Lawless, T. A.; Sims, R. J.; Butter, K. R.

    1993-06-01

    Uranium is often considered to be a mobile radioelement in the natural environment owing to its tendency to form stable complexes with a number of aqueous anions, particularly in oxidising milieu. A series of infiltration experiments were devised to investigate this migration behaviour under rigidly controlled laboratory conditions. Intact cores of Permo-Triassic Clashach Sandstone were pre-equilibrated with synthetic groundwater solutions and continuous flow-through of uranium monitored together with pH and concentrations of other ions. Prior to performing each experiment a simulation was carried out using a one-dimensional coupled chemical transport code, encompassing a thermodynamic description of the electrical double layer. These calculations together with electron microscopy indicated the potential role played by iron oxyhydroxide grain coatings in retarding the uranium plume. Thus, a second series of experiments was initiated on pre-acidified cores from which all surface exposed iron had been removed, allowing an assessment of the retention capacity of non-ferric components. Taken together, the data clearly illustrate the strong affinity of aqueous uranium species for natural surfaces even under strongly oxidising conditions. The success of the model in predicting a priori the dominant trends in uranium migration behaviour is encouraging and may aid in prioritising analytical requirements for investigations in more complex geochemical situations than those studied here.

  17. Mitochondrial oxidative stress in cancer-associated fibroblasts drives lactate production, promoting breast cancer tumor growth: understanding the aging and cancer connection.

    PubMed

    Balliet, Renee M; Capparelli, Claudia; Guido, Carmela; Pestell, Timothy G; Martinez-Outschoorn, Ubaldo E; Lin, Zhao; Whitaker-Menezes, Diana; Chiavarina, Barbara; Pestell, Richard G; Howell, Anthony; Sotgia, Federica; Lisanti, Michael P

    2011-12-01

    Increasing chronological age is the most significant risk factor for cancer. Recently, we proposed a new paradigm for understanding the role of the aging and the tumor microenvironment in cancer onset. In this model, cancer cells induce oxidative stress in adjacent stromal fibroblasts. This, in turn, causes several changes in the phenotype of the fibroblast including mitochondrial dysfunction, hydrogen peroxide production, and aerobic glycolysis, resulting in high levels of L-lactate production. L-lactate is then transferred from these glycolytic fibroblasts to adjacent epithelial cancer cells and used as "fuel" for oxidative mitochondrial metabolism.  Here, we created a new pre-clinical model system to directly test this hypothesis experimentally. To synthetically generate glycolytic fibroblasts, we genetically-induced mitochondrial dysfunction by knocking down TFAM using an sh-RNA approach.  TFAM is mitochondrial transcription factor A, which is important in functionally maintaining the mitochondrial respiratory chain. Interestingly, TFAM-deficient fibroblasts showed evidence of mitochondrial dysfunction and oxidative stress, with the loss of certain mitochondrial respiratory chain components, and the over-production of hydrogen peroxide and L-lactate. Thus, TFAM-deficient fibroblasts underwent metabolic reprogramming towards aerobic glycolysis.  Most importantly, TFAM-deficient fibroblasts significantly promoted tumor growth, as assayed using a human breast cancer (MDA-MB-231) xenograft model. These increases in glycolytic fibroblast driven tumor growth were independent of tumor angiogenesis. Mechanistically, TFAM-deficient fibroblasts increased the mitochondrial activity of adjacent epithelial cancer cells in a co-culture system, as seen using MitoTracker. Finally, TFAM-deficient fibroblasts also showed a loss of caveolin-1 (Cav-1), a known breast cancer stromal biomarker. Loss of stromal fibroblast Cav-1 is associated with early tumor recurrence, metastasis

  18. Mice produced by mitotic reprogramming of sperm injected into haploid parthenogenotes

    PubMed Central

    Suzuki, Toru; Asami, Maki; Hoffmann, Martin; Lu, Xin; Gužvić, Miodrag; Klein, Christoph A.; Perry, Anthony C. F.

    2016-01-01

    Sperm are highly differentiated and the activities that reprogram them for embryonic development during fertilization have historically been considered unique to the oocyte. We here challenge this view and demonstrate that mouse embryos in the mitotic cell cycle can also directly reprogram sperm for full-term development. Developmentally incompetent haploid embryos (parthenogenotes) injected with sperm developed to produce healthy offspring at up to 24% of control rates, depending when in the embryonic cell cycle injection took place. This implies that most of the first embryonic cell cycle can be bypassed in sperm genome reprogramming for full development. Remodelling of histones and genomic 5′-methylcytosine and 5′-hydroxymethylcytosine following embryo injection were distinct from remodelling in fertilization and the resulting 2-cell embryos consistently possessed abnormal transcriptomes. These studies demonstrate plasticity in the reprogramming of terminally differentiated sperm nuclei and suggest that different epigenetic pathways or kinetics can establish totipotency. PMID:27623537

  19. Choices for Induction of Pluripotency: Recent Developments in Human Induced Pluripotent Stem Cell Reprogramming Strategies.

    PubMed

    Brouwer, Marinka; Zhou, Huiqing; Nadif Kasri, Nael

    2016-02-01

    The ability to generate human induced pluripotent stem cells (iPSCs) from somatic cells provides tremendous promises for regenerative medicine and its use has widely increased over recent years. However, reprogramming efficiencies remain low and chromosomal instability and tumorigenic potential are concerns in the use of iPSCs, especially in clinical settings. Therefore, reprogramming methods have been under development to generate safer iPSCs with higher efficiency and better quality. Developments have mainly focused on the somatic cell source, the cocktail of reprogramming factors, the delivery method used to introduce reprogramming factors and culture conditions to maintain the generated iPSCs. This review discusses the developments on these topics and briefly discusses pros and cons of iPSCs in comparison with human embryonic stem cells generated from somatic cell nuclear transfer.

  20. Dedifferentiation and the role of sall4 in reprogramming and patterning during amphibian limb regeneration.

    PubMed

    Neff, Anton W; King, Michael W; Mescher, Anthony L

    2011-05-01

    A central feature of epimorphic regeneration during amphibian limb regeneration is cellular dedifferentiation. Two questions are discussed. First, what is the origin and nature of the soluble factors involved in triggering local cellular and tissue dedifferentiation? Secondly, what role does the key stem cell transcription factor Sall4 play in reprogramming gene expression during dedifferentiation? The pattern of Sall4 expression during Xenopus hindlimb regeneration is consistent with the hypothesis that Sall4 plays a role in dedifferentiation (reprogramming) and in maintaining limb blastema cells in an undifferentiated state. Sall4 is involved in maintenance of ESC pluripotency, is a major repressor of differentiation, plays a major role in reprogramming differentiated cells into iPSCs, and is a component of the stemness regulatory circuit of pluripotent ESCs and iPSCs. These functions suggest Sall4 as an excellent candidate to regulate reprogramming events that produce and maintain dedifferentiated blastema cells required for epimorphic regeneration.

  1. Limiting replication stress during somatic cell reprogramming reduces genomic instability in induced pluripotent stem cells

    PubMed Central

    Ruiz, Sergio; Lopez-Contreras, Andres J.; Gabut, Mathieu; Marion, Rosa M.; Gutierrez-Martinez, Paula; Bua, Sabela; Ramirez, Oscar; Olalde, Iñigo; Rodrigo-Perez, Sara; Li, Han; Marques-Bonet, Tomas; Serrano, Manuel; Blasco, Maria A.; Batada, Nizar N.; Fernandez-Capetillo, Oscar

    2015-01-01

    The generation of induced pluripotent stem cells (iPSC) from adult somatic cells is one of the most remarkable discoveries in recent decades. However, several works have reported evidence of genomic instability in iPSC, raising concerns on their biomedical use. The reasons behind the genomic instability observed in iPSC remain mostly unknown. Here we show that, similar to the phenomenon of oncogene-induced replication stress, the expression of reprogramming factors induces replication stress. Increasing the levels of the checkpoint kinase 1 (CHK1) reduces reprogramming-induced replication stress and increases the efficiency of iPSC generation. Similarly, nucleoside supplementation during reprogramming reduces the load of DNA damage and genomic rearrangements on iPSC. Our data reveal that lowering replication stress during reprogramming, genetically or chemically, provides a simple strategy to reduce genomic instability on mouse and human iPSC. PMID:26292731

  2. The therapeutic potential of cell identity reprogramming for the treatment of aging-related neurodegenerative disorders.

    PubMed

    Smith, Derek K; He, Miao; Zhang, Chun-Li; Zheng, Jialin C

    2016-02-01

    Neural cell identity reprogramming strategies aim to treat age-related neurodegenerative disorders with newly induced neurons that regenerate neural architecture and functional circuits in vivo. The isolation and neural differentiation of pluripotent embryonic stem cells provided the first in vitro models of human neurodegenerative disease. Investigation into the molecular mechanisms underlying stem cell pluripotency revealed that somatic cells could be reprogrammed to induced pluripotent stem cells (iPSCs) and these cells could be used to model Alzheimer disease, amyotrophic lateral sclerosis, Huntington disease, and Parkinson disease. Additional neural precursor and direct transdifferentiation strategies further enabled the induction of diverse neural linages and neuron subtypes both in vitro and in vivo. In this review, we highlight neural induction strategies that utilize stem cells, iPSCs, and lineage reprogramming to model or treat age-related neurodegenerative diseases, as well as, the clinical challenges related to neural transplantation and in vivo reprogramming strategies.

  3. Chemically Induced Reprogramming of Somatic Cells to Pluripotent Stem Cells and Neural Cells.

    PubMed

    Biswas, Dhruba; Jiang, Peng

    2016-02-06

    The ability to generate transplantable neural cells in a large quantity in the laboratory is a critical step in the field of developing stem cell regenerative medicine for neural repair. During the last few years, groundbreaking studies have shown that cell fate of adult somatic cells can be reprogrammed through lineage specific expression of transcription factors (TFs)-and defined culture conditions. This key concept has been used to identify a number of potent small molecules that could enhance the efficiency of reprogramming with TFs. Recently, a growing number of studies have shown that small molecules targeting specific epigenetic and signaling pathways can replace all of the reprogramming TFs. Here, we provide a detailed review of the studies reporting the generation of chemically induced pluripotent stem cells (ciPSCs), neural stem cells (ciNSCs), and neurons (ciN). We also discuss the main mechanisms of actions and the pathways that the small molecules regulate during chemical reprogramming.

  4. A predictive computational framework for direct reprogramming between human cell types.

    PubMed

    Rackham, Owen J L; Firas, Jaber; Fang, Hai; Oates, Matt E; Holmes, Melissa L; Knaupp, Anja S; Suzuki, Harukazu; Nefzger, Christian M; Daub, Carsten O; Shin, Jay W; Petretto, Enrico; Forrest, Alistair R R; Hayashizaki, Yoshihide; Polo, Jose M; Gough, Julian

    2016-03-01

    Transdifferentiation, the process of converting from one cell type to another without going through a pluripotent state, has great promise for regenerative medicine. The identification of key transcription factors for reprogramming is currently limited by the cost of exhaustive experimental testing of plausible sets of factors, an approach that is inefficient and unscalable. Here we present a predictive system (Mogrify) that combines gene expression data with regulatory network information to predict the reprogramming factors necessary to induce cell conversion. We have applied Mogrify to 173 human cell types and 134 tissues, defining an atlas of cellular reprogramming. Mogrify correctly predicts the transcription factors used in known transdifferentiations. Furthermore, we validated two new transdifferentiations predicted by Mogrify. We provide a practical and efficient mechanism for systematically implementing novel cell conversions, facilitating the generalization of reprogramming of human cells. Predictions are made available to help rapidly further the field of cell conversion.

  5. RNA-based tools for nuclear reprogramming and lineage-conversion: towards clinical applications.

    PubMed

    Bernal, Juan A

    2013-12-01

    The therapeutic potential of induced pluripotent stem cells (iPSCs) is well established. Safety concerns remain, however, and these have driven considerable efforts aimed at avoiding host genome alteration during the reprogramming process. At present, the tools used to generate human iPSCs include (1) DNA-based integrative and non-integrative methods and (2) DNA-free reprogramming technologies, including RNA-based approaches. Because of their combined efficiency and safety characteristics, RNA-based methods have emerged as the most promising tool for future iPSC-based regenerative medicine applications. Here, I will discuss novel recent advances in reprogramming technology, especially those utilizing the Sendai virus (SeV) and synthetic modified mRNA. In the future, these technologies may find utility in iPSC reprogramming for cellular lineage-conversion, and its subsequent use in cell-based therapies.

  6. Chemically Induced Reprogramming of Somatic Cells to Pluripotent Stem Cells and Neural Cells

    PubMed Central

    Biswas, Dhruba; Jiang, Peng

    2016-01-01

    The ability to generate transplantable neural cells in a large quantity in the laboratory is a critical step in the field of developing stem cell regenerative medicine for neural repair. During the last few years, groundbreaking studies have shown that cell fate of adult somatic cells can be reprogrammed through lineage specific expression of transcription factors (TFs)-and defined culture conditions. This key concept has been used to identify a number of potent small molecules that could enhance the efficiency of reprogramming with TFs. Recently, a growing number of studies have shown that small molecules targeting specific epigenetic and signaling pathways can replace all of the reprogramming TFs. Here, we provide a detailed review of the studies reporting the generation of chemically induced pluripotent stem cells (ciPSCs), neural stem cells (ciNSCs), and neurons (ciN). We also discuss the main mechanisms of actions and the pathways that the small molecules regulate during chemical reprogramming. PMID:26861316

  7. Reprogramming somatic cells to pluripotency: a fresh look at Yamanaka's model.

    PubMed

    Li, Yangxin; Shen, Zhenya; Shelat, Harnath; Geng, Yong-Jian

    2013-12-01

    In 2006, Dr Shinya Yamanaka succeeded to reprogram somatic cells into pluripotent stem cells (iPSC) by delivering the genes encoding Oct4, Sox2, Klf4, and c-Myc. This achievement represents a fundamental breakthrough in stem cell biology and opens up a new era in regenerative medicine. However, the molecular processes by which somatic cells are reprogrammed into iPSC remain poorly understood. In 2009, Yamanaka proposed the elite and stochastic models for reprogramming mechanisms. To date, many investigators in the field of iPSC research support the concept of stochastic model, i.e., somatic cell reprogramming is an event of epigenetic transformation. A mathematical model, f (Cd, k), has also been proposed to predict the stochastic process. Here we wish to revisit the Yamanaka model and summarize the recent advances in this research field.

  8. Cell motility and local viscoelasticity of fibroblasts.

    PubMed

    Park, S; Koch, D; Cardenas, R; Käs, J; Shih, C K

    2005-12-01

    Viscoelastic changes of the lamellipodial actin cytoskeleton are a fundamental element of cell motility. Thus, the correlation between the local viscoelastic properties of the lamellipodium (including the transitional region to the cell body) and the speed of lamellipodial extension is studied for normal and malignantly transformed fibroblasts. Using our atomic force microscopy-based microrheology technique, we found different mechanical properties between the lamellipodia of malignantly transformed fibroblasts (H-ras transformed and SV-T2 fibroblasts) and normal fibroblasts (BALB 3T3 fibroblasts). The average elastic constants, K, in the leading edge of SV-T2 fibroblasts (0.48 +/- 0.51 kPa) and of H-ras transformed fibroblasts (0.42 +/- 0.35 kPa) are significantly lower than that of BALB 3T3 fibroblasts (1.01 +/- 0.40 kPa). The analysis of time-lapse phase contrast images shows that the decrease in the elastic constant, K, for malignantly transformed fibroblasts is correlated with the enhanced motility of the lamellipodium. The measured mean speeds are 6.1 +/- 4.5 microm/h for BALB 3T3 fibroblasts, 13.1 +/- 5.2 microm/h for SV-T2 fibroblasts, and 26.2 +/- 11.5 microm/h for H-ras fibroblasts. Furthermore, the elastic constant, K, increases toward the cell body in many instances which coincide with an increase in actin filament density toward the cell body. The correlation between the enhanced motility and the decrease in viscoelastic moduli supports the Elastic Brownian Ratchet model for driving lamellipodia extension.

  9. Identifying candidate oocyte reprogramming factors using cross-species global transcriptional analysis.

    PubMed

    Awe, Jason P; Byrne, James A

    2013-04-01

    There is mounting evidence to suggest that the epigenetic reprogramming capacity of the oocyte is superior to that of the current factor-based reprogramming approaches and that some factor-reprogrammed induced pluripotent stem cells (iPSCs) retain a degree of epigenetic memory that can influence differentiation capacity and may be linked to the observed expression of immunogenicity genes in iPSC derivatives. One hypothesis for this differential reprogramming capacity is the "chromatin loosening/enhanced reprogramming" concept, as previously described by John Gurdon and Ian Wilmut, as well as others, which postulates that the oocyte possesses factors that loosen the somatic cell chromatin structure, providing the epigenetic and transcriptional regulatory factors more ready access to repressed genes and thereby significantly increasing epigenetic reprogramming. However, to empirically test this hypothesis a list of candidate oocyte reprogramming factors (CORFs) must be ascertained that are significantly expressed in metaphase II oocytes. Previous studies have focused on intraspecies or cross-species transcriptional analysis of up to two different species of oocytes. In this study, we have identified eight CORFs (ARID2, ASF1A, ASF1B, DPPA3, ING3, MSL3, H1FOO, and KDM6B) based on unbiased global transcriptional analysis of oocytes from three different species (human, rhesus monkey, and mouse) that both demonstrate significant (p<0.05, FC>3) expression in oocytes of all three species and have well-established roles in loosening/opening up chromatin structure. We also identified an additional 15 CORFs that fit within our proposed "chromatin opening/fate transformative" (COFT) model. These CORFs may be able to augment Shinya Yamanaka's previously identified reprogramming factors (OCT4, SOX2, KLF4, and cMYC) and potentially facilitate the removal of epigenetic memory in iPSCs and/or reduce the expression of immunogenicity genes in iPSC derivatives, and may have

  10. Induced regeneration--the progress and promise of direct reprogramming for heart repair.

    PubMed

    Addis, Russell C; Epstein, Jonathan A

    2013-07-01

    Regeneration of cardiac tissue has the potential to transform cardiovascular medicine. Recent advances in stem cell biology and direct reprogramming, or transdifferentiation, have produced powerful new tools to advance this goal. In this Review we examine key developments in the generation of new cardiomyocytes in vitro as well as the exciting progress that has been made toward in vivo reprogramming of cardiac tissue. We also address controversies and hurdles that challenge the field.

  11. From Stealing Fire to Cellular Reprogramming: A Scientific History Leading to the 2012 Nobel Prize

    PubMed Central

    Lensch, M. William; Mummery, Christine L.

    2013-01-01

    Cellular reprogramming was recently “crowned” with the award of the Nobel Prize to two of its groundbreaking researchers, Sir John Gurdon and Shinya Yamanaka. The recent link between reprogramming and stem cells makes this appear almost a new field of research, but its historical roots have actually spanned more than a century. Here, the Nobel Prize in Physiology or Medicine 2012 is placed in its historical context. PMID:24052937

  12. From stealing fire to cellular reprogramming: a scientific history leading to the 2012 Nobel Prize.

    PubMed

    Lensch, M William; Mummery, Christine L

    2013-06-04

    Cellular reprogramming was recently "crowned" with the award of the Nobel Prize to two of its groundbreaking researchers, Sir John Gurdon and Shinya Yamanaka. The recent link between reprogramming and stem cells makes this appear almost a new field of research, but its historical roots have actually spanned more than a century. Here, the Nobel Prize in Physiology or Medicine 2012 is placed in its historical context.

  13. Experimental serpentinization of intact dunite cores

    NASA Astrophysics Data System (ADS)

    Luhmann, A. J.; Tutolo, B. M.; Kong, X. Z.; Bagley, B. C.; Schaen, A. T.; Saar, M. O.; Seyfried, W. E., Jr.

    2014-12-01

    Serpentinization in ultramafic-hosted hydrothermal systems, such as Lost City, produces relatively cool and alkaline fluids that support diverse ecosystems. To simulate serpentinization in such systems, we conducted single-pass, flow-through experiments on dunite cores cut out of a sample from Jackson County, North Carolina. Experimental seawater prepared using laboratory-grade reagents and standards was pumped through a core at 150ºC and 150 bar pore-fluid outlet pressure at a flow rate of 0.01 ml/min. An additional experiment will be conducted at 200ºC. At 150ºC, permeability decreased by 2.3 times with reaction progress over the course of the 36 day experiment. Fluid-rock reaction generally produced CO2, H2, CH4, and CO concentrations of 100 μmol/kg, up to 40 μmol/kg, 2 μmol/kg, and less than 1 μmol/kg, respectively. Outlet fluid chemistry was relatively stable, except for initial peaks in Al, Ba, Fe, Mn, and Si. pH of outlet fluids increased with reaction progress, but it was always lower (6.9-7.4) than the initial seawater (7.8). X-ray computed tomography scans were/will be collected for both pre- and post-experimental cores. The combination of flow-through experiments on solid, intact rock cores cut out of natural samples and X-ray tomography permits visualization and quantification of mineralogical changes and flow path evolution during serpentinization. This approach further permits physical and chemical processes to be documented on a fine scale to better understand feedbacks between chemical reactions and flow fields, with implications for ultramafic-hosted hydrothermal systems.

  14. Advances and Challenges on Cancer Cells Reprogramming Using Induced Pluripotent Stem Cells Technologies

    PubMed Central

    Câmara, Diana Aparecida Dias; Mambelli, Lisley Inata; Porcacchia, Allan Saj; Kerkis, Irina

    2016-01-01

    Cancer cells transformation into a normal state or into a cancer cell population which is less tumorigenic than the initial one is a challenge that has been discussed during last decades and it is still far to be solved. Due to the highly heterogeneous nature of cancer cells, such transformation involves many genetic and epigenetic factors which are specific for each type of tumor. Different methods of cancer cells reprogramming have been established and can represent a possibility to obtain less tumorigenic or even normal cells. These methods are quite complex, thus a simple and efficient method of reprogramming is still required. As soon as induced pluripotent stem cells (iPSC) technology, which allowed to reprogram terminally differentiated cells into embryonic stem cells (ESC)-like, was developed, the method strongly attracted the attention of researches, opening new perspectives for stem cell (SC) personalized therapies and offering a powerful in vitro model for drug screening. This technology is also used to reprogram cancer cells, thus providing a modern platform to study cancer-related genes and the interaction between these genes and the cell environment before and after reprogramming, in order to elucidate the mechanisms of cancer initiation and progression. The present review summarizes recent advances on cancer cells reprogramming using iPSC technology and shows the progress achieved in such field. PMID:27994667

  15. Nuclear reprogramming of sperm and somatic nuclei in eggs and oocytes.

    PubMed

    Teperek, Marta; Miyamoto, Kei

    2013-01-01

    Eggs and oocytes have a prominent ability to reprogram sperm nuclei for ensuring embryonic development. The reprogramming activity that eggs/oocytes intrinsically have towards sperm is utilised to reprogram somatic nuclei injected into eggs/oocytes in nuclear transfer (NT) embryos. NT embryos of various species can give rise to cloned animals, demonstrating that eggs/oocytes can confer totipotency even to somatic nuclei. However, many studies indicate that reprogramming of somatic nuclei is not as efficient as that of sperm nuclei. In this review, we explain how and why sperm and somatic nuclei are differentially reprogrammed in eggs/oocytes. Recent studies have shown that sperm chromatin is epigenetically modified to be adequate for early embryonic development, while somatic nuclei do not have such modifications. Moreover, epigenetic memories encoded in sperm chromatin are transgenerationally inherited, implying unique roles of sperm. We also discuss whether somatic nuclei can be artificially modified to acquire sperm-like chromatin states in order to increase the efficiency of nuclear reprogramming.

  16. Common Telomere Changes during In Vivo Reprogramming and Early Stages of Tumorigenesis.

    PubMed

    Marión, Rosa M; López de Silanes, Isabel; Mosteiro, Lluc; Gamache, Benjamin; Abad, María; Guerra, Carmen; Megías, Diego; Serrano, Manuel; Blasco, Maria A

    2017-02-14

    Reprogramming of differentiated cells into induced pluripotent stem cells has been recently achieved in vivo in mice. Telomeres are essential for chromosomal stability and determine organismal life span as well as cancer growth. Here, we study whether tissue dedifferentiation induced by in vivo reprogramming involves changes at telomeres. We find telomerase-dependent telomere elongation in the reprogrammed areas. Notably, we found highly upregulated expression of the TRF1 telomere protein in the reprogrammed areas, which was independent of telomere length. Moreover, TRF1 inhibition reduced in vivo reprogramming efficiency. Importantly, we extend the finding of TRF1 upregulation to pathological tissue dedifferentiation associated with neoplasias, in particular during pancreatic acinar-to-ductal metaplasia, a process that involves transdifferentiation of adult acinar cells into ductal-like cells due to K-Ras oncogene expression. These findings place telomeres as important players in cellular plasticity both during in vivo reprogramming and in pathological conditions associated with increased plasticity, such as cancer.

  17. Small molecules, big roles -- the chemical manipulation of stem cell fate and somatic cell reprogramming.

    PubMed

    Zhang, Yu; Li, Wenlin; Laurent, Timothy; Ding, Sheng

    2012-12-01

    Despite the great potential of stem cells for basic research and clinical applications, obstacles - such as their scarce availability and difficulty in controlling their fate - need to be addressed to fully realize their potential. Recent achievements of cellular reprogramming have enabled the generation of induced pluripotent stem cells (iPSCs) or other lineage-committed cells from more accessible and abundant somatic cell types by defined genetic factors. However, serious concerns remain about the efficiency and safety of current genetic approaches to cell reprogramming and traditional culture systems that are used for stem cell maintenance. As a complementary approach, small molecules that target specific signaling pathways, epigenetic processes and other cellular processes offer powerful tools for manipulating cell fate to a desired outcome. A growing number of small molecules have been identified to maintain the self-renewal potential of stem cells, to induce lineage differentiation and to facilitate reprogramming by increasing the efficiency of reprogramming or by replacing genetic reprogramming factors. Furthermore, mechanistic investigations of the effects of these chemicals also provide new biological insights. Here, we examine recent achievements in the maintenance of stem cells, including pluripotent and lineage-specific stem cells, and in the control of cell fate conversions, including iPSC reprogramming, conversion of primed to naïve pluripotency, and transdifferentiation, with an emphasis on manipulation with small molecules.

  18. Development Refractoriness of MLL-Rearranged Human B Cell Acute Leukemias to Reprogramming into Pluripotency.

    PubMed

    Muñoz-López, Alvaro; Romero-Moya, Damià; Prieto, Cristina; Ramos-Mejía, Verónica; Agraz-Doblas, Antonio; Varela, Ignacio; Buschbeck, Marcus; Palau, Anna; Carvajal-Vergara, Xonia; Giorgetti, Alessandra; Ford, Anthony; Lako, Majlinda; Granada, Isabel; Ruiz-Xivillé, Neus; Rodríguez-Perales, Sandra; Torres-Ruíz, Raul; Stam, Ronald W; Fuster, Jose Luis; Fraga, Mario F; Nakanishi, Mahito; Cazzaniga, Gianni; Bardini, Michela; Cobo, Isabel; Bayon, Gustavo F; Fernandez, Agustin F; Bueno, Clara; Menendez, Pablo

    2016-10-11

    Induced pluripotent stem cells (iPSCs) are a powerful tool for disease modeling. They are routinely generated from healthy donors and patients from multiple cell types at different developmental stages. However, reprogramming leukemias is an extremely inefficient process. Few studies generated iPSCs from primary chronic myeloid leukemias, but iPSC generation from acute myeloid or lymphoid leukemias (ALL) has not been achieved. We attempted to generate iPSCs from different subtypes of B-ALL to address the developmental impact of leukemic fusion genes. OKSM(L)-expressing mono/polycistronic-, retroviral/lentiviral/episomal-, and Sendai virus vector-based reprogramming strategies failed to render iPSCs in vitro and in vivo. Addition of transcriptomic-epigenetic reprogramming "boosters" also failed to generate iPSCs from B cell blasts and B-ALL lines, and when iPSCs emerged they lacked leukemic fusion genes, demonstrating non-leukemic myeloid origin. Conversely, MLL-AF4-overexpressing hematopoietic stem cells/B progenitors were successfully reprogrammed, indicating that B cell origin and leukemic fusion gene were not reprogramming barriers. Global transcriptome/DNA methylome profiling suggested a developmental/differentiation refractoriness of MLL-rearranged B-ALL to reprogramming into pluripotency.

  19. Advances and Challenges on Cancer Cells Reprogramming Using Induced Pluripotent Stem Cells Technologies.

    PubMed

    Câmara, Diana Aparecida Dias; Mambelli, Lisley Inata; Porcacchia, Allan Saj; Kerkis, Irina

    2016-01-01

    Cancer cells transformation into a normal state or into a cancer cell population which is less tumorigenic than the initial one is a challenge that has been discussed during last decades and it is still far to be solved. Due to the highly heterogeneous nature of cancer cells, such transformation involves many genetic and epigenetic factors which are specific for each type of tumor. Different methods of cancer cells reprogramming have been established and can represent a possibility to obtain less tumorigenic or even normal cells. These methods are quite complex, thus a simple and efficient method of reprogramming is still required. As soon as induced pluripotent stem cells (iPSC) technology, which allowed to reprogram terminally differentiated cells into embryonic stem cells (ESC)-like, was developed, the method strongly attracted the attention of researches, opening new perspectives for stem cell (SC) personalized therapies and offering a powerful in vitro model for drug screening. This technology is also used to reprogram cancer cells, thus providing a modern platform to study cancer-related genes and the interaction between these genes and the cell environment before and after reprogramming, in order to elucidate the mechanisms of cancer initiation and progression. The present review summarizes recent advances on cancer cells reprogramming using iPSC technology and shows the progress achieved in such field.

  20. Gastrointestinal Fibroblasts Have Specialized, Diverse Transcriptional Phenotypes: A Comprehensive Gene Expression Analysis of Human Fibroblasts

    PubMed Central

    Ishii, Genichiro; Aoyagi, Kazuhiko; Sasaki, Hiroki; Ochiai, Atsushi

    2015-01-01

    Background Fibroblasts are the principal stromal cells that exist in whole organs and play vital roles in many biological processes. Although the functional diversity of fibroblasts has been estimated, a comprehensive analysis of fibroblasts from the whole body has not been performed and their transcriptional diversity has not been sufficiently explored. The aim of this study was to elucidate the transcriptional diversity of human fibroblasts within the whole body. Methods Global gene expression analysis was performed on 63 human primary fibroblasts from 13 organs. Of these, 32 fibroblasts from gastrointestinal organs (gastrointestinal fibroblasts: GIFs) were obtained from a pair of 2 anatomical sites: the submucosal layer (submucosal fibroblasts: SMFs) and the subperitoneal layer (subperitoneal fibroblasts: SPFs). Using hierarchical clustering analysis, we elucidated identifiable subgroups of fibroblasts and analyzed the transcriptional character of each subgroup. Results In unsupervised clustering, 2 major clusters that separate GIFs and non-GIFs were observed. Organ- and anatomical site-dependent clusters within GIFs were also observed. The signature genes that discriminated GIFs from non-GIFs, SMFs from SPFs, and the fibroblasts of one organ from another organ consisted of genes associated with transcriptional regulation, signaling ligands, and extracellular matrix remodeling. Conclusions GIFs are characteristic fibroblasts with specific gene expressions from transcriptional regulation, signaling ligands, and extracellular matrix remodeling related genes. In addition, the anatomical site- and organ-dependent diversity of GIFs was also discovered. These features of GIFs contribute to their specific physiological function and homeostatic maintenance, and create a functional diversity of the gastrointestinal tract. PMID:26046848

  1. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  2. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  3. 50 CFR 622.186 - Landing fish intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-Grouper Fishery of the South Atlantic Region § 622.186 Landing fish intact. (a) South Atlantic snapper-grouper in or from the South Atlantic EEZ must be maintained with head and fins intact, except as..., snapper-grouper lawfully harvested in Bahamian waters are exempt from the requirement that they...

  4. 50 CFR 622.186 - Landing fish intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-Grouper Fishery of the South Atlantic Region § 622.186 Landing fish intact. (a) South Atlantic snapper-grouper in or from the South Atlantic EEZ must be maintained with head and fins intact, except as..., snapper-grouper lawfully harvested in Bahamian waters are exempt from the requirement that they...

  5. 50 CFR 622.455 - Landing spiny lobster intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Landing spiny lobster intact. 622.455... ATLANTIC Spiny Lobster Fishery of Puerto Rico and the U.S. Virgin Islands § 622.455 Landing spiny lobster intact. (a) A Caribbean spiny lobster in or from the Caribbean EEZ must be maintained with head...

  6. 50 CFR 622.455 - Landing spiny lobster intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Landing spiny lobster intact. 622.455... ATLANTIC Spiny Lobster Fishery of Puerto Rico and the U.S. Virgin Islands § 622.455 Landing spiny lobster intact. (a) A Caribbean spiny lobster in or from the Caribbean EEZ must be maintained with head...

  7. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  8. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  9. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  10. 50 CFR 622.10 - Landing fish intact--general.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH... landing fish intact that are broadly applicable to finfish in the Gulf EEZ and Caribbean EEZ, as specified... intact. (a) Finfish in or from the Gulf EEZ or Caribbean EEZ, except as specified in paragraphs (b)...

  11. 50 CFR 622.10 - Landing fish intact--general.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH... landing fish intact that are broadly applicable to finfish in the Gulf EEZ and Caribbean EEZ, as specified... intact. (a) Finfish in or from the Gulf EEZ or Caribbean EEZ, except as specified in paragraphs (b)...

  12. Toxicity of silver nanoparticles in mouse embryonic stem cells and chemical based reprogramming of somatic cells to sphere cells

    NASA Astrophysics Data System (ADS)

    Rajanahalli Krishnamurthy, Pavan

    Abstract 1: Silver nanoparticles (Ag Np's) have an interesting surface chemistry and unique plasmonic properties. They are used in a wide variety of applications ranging from consumer products like socks, medical dressing, computer chips and it is also shown to have antimicrobial, anti bacterial activity and wound healing. Ag Np toxicity studies have been limited to date which needs to be critically addressed due to its wide applications. Mouse embryonic stem (MES) cells represent a unique cell population with the ability to undergo both self renewal and differentiation. They exhibit very stringent and tightly regulated mechanisms to circumvent DNA damage and stress response. We used 10 nm coated (polysaccharide) and uncoated Ag Np's to test its toxic effects on MES cells. MES cells and embryoid bodies (EB's) were treated with two concentrations of Ag Np's: 5 microg/ml and 50 ug/ml and exposed for 24, 48 and 72 hours. Increased cell death, ROS production and loss of mitochondrial membrane potential and alkaline phosphatase (AP) occur in a time and a concentration dependant manner. Due to increased cell death, there is a progressive increase in Annexin V (apoptosis) and Propidium Iodide (PI) staining (necrosis). Oct4 and Nanog undergo ubiquitination and dephosphorylation post-translational modifications in MES cells thereby altering gene expression of pluripotency factors and differentiation of EB's into all the three embryonic germ layers with specific growth factors were also inhibited after Ag Np exposure. Flow cytometry analysis revealed Ag Np's treated cells had altered cell cycle phases correlating with altered self renewal capacity. Our results suggest that Ag Np's effect MES cell self renewal, pluripotency and differentiation and serves as a perfect model system for studying toxicity induced by engineered Ag Np's. Abstract 2: The reprogramming of fibroblasts to pluripotent stem cells and the direct conversion of fibroblasts to functional neurons has been

  13. The many roads to Rome: induction of neural precursor cells from fibroblasts.

    PubMed

    Lujan, Ernesto; Wernig, Marius

    2012-10-01

    The experimental induction of specific cell fates in related or unrelated lineages has fascinated developmental biologists for decades. The evaluation of altered cell fates in response to ectopic expression during embryonic development has been a standard assay for interrogating gene function. However, until recently examples of cell lineage conversions were limited to closely related and primitive cell types. The induction of pluripotency in fibroblasts prominently highlighted that combinations of transcription factors can be extremely powerful and are much more effective than single genes. On the basis of this conclusion we previously identified transcription factor combinations that directly induce functional neuronal cells from mesodermal and endodermal cells. This work has evoked numerous additional studies demonstrating direct lineage conversion into neural and other lineages. Here, we review the generation of neural progenitor cells from fibroblasts, which is the newest addition to the arena of induced cell types. Surprisingly, two fundamentally different approaches have been taken to induce this cell type, one direct approach and another that involves the intermediate generation of a partially reprogrammed pluripotent state.

  14. Scopoletin has a potential activity for anti-aging via autophagy in human lung fibroblasts.

    PubMed

    Nam, Hyang; Kim, Moon-Moo

    2015-03-15

    Autophagy was known to be associated with aging in addition to cancer and neurodegeneration. The effects of scopoletin on autophagy and anti-aging were investigated in human lung fibroblast cell line, IMR 90. Here we show that scopoletin induces autophagy. It is also identified that the modulation of p53 by scopoletin are related to the induction of autophagy. Moreover, the level of SA-β-Gal staining, an aging marker, is reduced by scopoletin. In addition, while the expression levels of histone deacetylases such as HDAC1, SIRT1 and SIRT6 are increased in IMR 90 cells in the presence of scopoletin, the expression levels of histone acetyltransferases are decreased. Furthermore, scopoletin enhances the level of transcription factors such as Nrf-2and p-FoxO1 related to anti-aging. In addition, scopoletin modulates the reprogramming proteins. Therefore, these findings suggest that scopoletin could exert a positive effect on anti-aging related to autophagy through modulation of p53 in human lung fibroblasts.

  15. Effect of primary culture medium type for culture of canine fibroblasts on production of cloned dogs.

    PubMed

    Kim, Geon A; Oh, Hyun Ju; Kim, Min Jung; Jo, Young Kwang; Choi, Jin; Kim, Jin Wook; Lee, Tae Hee; Lee, Byeong Chun

    2015-09-01

    Fibroblasts are common source of donor cells for SCNT. It is suggested that donor cells' microenvironment, including the primary culture, affects development of reconstructed embryos. To prove this, canine embryos were cloned with fibroblasts that were cultured in two different primary media (RCMEp vs. Dulbecco's modified Eagle's medium [DMEM]) and in vivo developments were compared with relative amount of stemness, reprogramming, apoptosis gene transcripts, and telomerase activity. Donor cells cultured in RCMEp contained a significantly higher amount of SOX2, NANOG, DPPA2, REXO1, HDAC, DNMT1, MECP2 and telomerase activity than those cultured in DMEM (P < 0.05). In vivo developmental potential of cloned embryos with donor cells cultured in RCMEp had a higher birth rate than that of embryos derived from DMEM (P < 0.05). The culture medium can induce changes in gene expression of donor cells and telomerase activity, and these alterations can also affect in vivo developmental competence of the cloned embryos.

  16. Skin Fibroblasts from Patients with Type 1 Diabetes (T1D) Can Be Chemically Transdifferentiated into Insulin-Expressing Clusters: A Transgene-Free Approach

    PubMed Central

    Pereyra-Bonnet, Federico; Gimeno, María L.; Argumedo, Nelson R.; Ielpi, Marcelo; Cardozo, Johana A.; Giménez, Carla A.; Hyon, Sung-Ho; Balzaretti, Marta; Loresi, Mónica; Fainstein-Day, Patricia; Litwak, León E.; Argibay, Pablo F.

    2014-01-01

    The conversion of differentiated cells into insulin-producing cells is a promising approach for the autologous replacement of pancreatic cells in patients with type 1 diabetes (T1D). At present, cellular reprogramming strategies encompass ethical problems, epigenetic failure or teratoma formation, which has prompted the development of new approaches. Here, we report a novel technique for the conversion of skin fibroblasts from T1D patients into insulin-expressing clusters using only drug-based induction. Our results demonstrate that skin fibroblasts from diabetic patients have pancreatic differentiation capacities and avoid the necessity of using transgenic strategies, stem cell sources or global demethylation steps. These findings open new possibilities for studying diabetes mechanisms, drug screenings and ultimately autologous transgenic-free regenerative medicine therapies in patients with T1D. PMID:24963634

  17. Development of spatial database on intact forest landscapes of India

    NASA Astrophysics Data System (ADS)

    Sudhakar Reddy, C.; Singh, Jyoti; Jha, C. S.; Diwakar, P. G.; Dadhwal, V. K.

    2017-01-01

    There is an increased interest in identifying the status of biodiversity in different spatial and temporal scales. The objective of the current research is to prepare a consistent spatial database of intact forest landscapes of India. The intact forest landscapes are located in the Himalayas, Andaman & Nicobar Islands, Western Ghats and Sunderbans. At national level 237 forest landscapes and 5.4% of the total natural forest remained as intact in India. Current intact forest landscapes of India consists of blocks larger than 10 km2 covering an area of 34,061 km2. Of the total area under intact forest landscapes, Eastern Himalayas represent 76.7% of the area, followed by Western Himalayas (8.8%), Andaman & Nicobar Islands (6.2%) and Western Ghats (5.7%). The largest intact forest landscape block occupies an area of 3342.9 km2 (9.8%) is found in western Arunachal Pradesh. Temperate forest zone represents the highest intactness (56.6%), followed by subtropical zone (19.2%), tropical zone (18.6%) and alpine zone (5.6%). Himalayan moist temperate forests represent the highest area (39.1%) of intact forest landscapes followed by subtropical broad-leaved hill forests, wet evergreen forests, and montane wet temperate forests. It is estimated that 4.4% of the area of intact forest landscapes fall inside the existing 47 protected areas. The results of the analysis best suited as input for the process of identification of new protected areas. The study recommends fine-scale mapping of biodiversity within the intact forest landscapes and to prepare efficient conservation plans.

  18. Vesta Is Not an Intact Protoplanet

    NASA Astrophysics Data System (ADS)

    Consolmagno, Guy; Turrini, Diego; Golabeck, Gregor; Jutzi, Martin; Sirono, Sin-iti; Svetsov, Vladimir; Tsiganis, Kleomenis

    2014-11-01

    Asteroid 4 Vesta has been identified as the likely source of howardite, eucrite, and diogenite (HED) basaltic achondrite meteorites, whose parent body differentiated and started solidifying within 3 Ma after the condensation of the Ca-Al-rich inclusions (CAIs). The formation of Jupiter and the disk-driven migration of the giant planets also occurred during this period; thus it was expected that Vesta could provide an intact record of large-scale early episodes of planetary migration and bombardment as in the proposed Jovian Early Bombardment and the “Grand Tack” scenarios. However, the results of the Dawn mission detailing Vesta’s mass, volume, density, and surface characteristics provide challenges for modeling the structure and evolution of this asteroid. All proposed models for the generation of the HEDs require the presence of a substantial olivine-rich mantle. But recent work on the depth of excavation of the large basins at the south pole of Vesta suggests that because there is not abundant mantle olivine visible on Vesta or in the Vestoid family asteroids, the crust of Vesta must be at least 80 km thick. Such a thick crust is radically at odds with previous models; should it exist, it ought to manifest itself in other ways such as Vesta’s density structure and bulk chemical composition. However, we find that no Vesta model of iron core, olivine-rich mantle, and HED crust can match the joint constraints of (a) Vesta’s density as derived from the gravity field observed by Dawn; (b) the observed depletion of sodium and potassium and trace element enrichments of the HED meteorites; and (c) the absence of exposed olivine on Vesta’s surface, among Vestoid asteroids, or in our collection of basaltic meteorites. Either Vesta was subjected to a radical change in composition, presumably due to the intense collisional environment where and when it formed, or the asteroid we see today is in fact a reaccretion of material formed elsewhere from now

  19. Generation of Patient-Specific induced Pluripotent Stem Cell from Peripheral Blood Mononuclear Cells by Sendai Reprogramming Vectors.

    PubMed

    Quintana-Bustamante, Oscar; Segovia, Jose C

    2016-01-01

    Induced pluripotent stem cells (iPSC) technology has changed preclinical research since their generation was described by Shinya Yamanaka in 2006. iPSCs are derived from somatic cells after being reprogrammed back to an embryonic state by specific combination of reprogramming factors. These reprogrammed cells resemble all the characteristic of embryonic stem cells (ESC). The reprogramming technology is even more valuable to research diseases biology and treatment by opening gene and cell therapies in own patient's iPSC. Patient-specific iPSC can be generated from a large variety of patient cells by any of the myriad of reprogramming platforms described. Here, we describe the generation of patient-specific iPSC from patient peripheral blood mononuclear cells by Sendai Reprogramming vectors.

  20. Sphingolipid domains in the plasma membranes of fibroblasts are not enriched with cholesterol

    SciTech Connect

    Frisz, Jessica F.; Klitzing, Haley A.; Lou, Kaiyan; Hutcheon, Ian D.; Weber, Peter K.; Zimmerberg, Joshua; Kraft, Mary L.

    2013-04-22

    The plasma membranes of mammalian cells are widely expected to contain domains that are enriched with cholesterol and sphingolipids. In this work, we have used high-resolution secondary ion mass spectrometry to directly map the distributions of isotope-labeled cholesterol and sphingolipids in the plasma membranes of intact fibroblast cells. Although acute cholesterol depletion reduced sphingolipid domain abundance, cholesterol was evenly distributed throughout the plasma membrane and was not enriched within the sphingolipid domains. As a result, we rule out favorable cholesterol-sphingolipid interactions as dictating plasma membrane organization in fibroblast cells. Because the sphingolipid domains are disrupted by drugs that depolymerize the cells actin cytoskeleton, cholesterol must instead affect the sphingolipid organization via an indirect mechanism that involves the cytoskeleton.

  1. Sphingolipid Domains in the Plasma Membranes of Fibroblasts Are Not Enriched with Cholesterol*

    PubMed Central

    Frisz, Jessica F.; Klitzing, Haley A.; Lou, Kaiyan; Hutcheon, Ian D.; Weber, Peter K.; Zimmerberg, Joshua; Kraft, Mary L.

    2013-01-01

    The plasma membranes of mammalian cells are widely expected to contain domains that are enriched with cholesterol and sphingolipids. In this work, we have used high-resolution secondary ion mass spectrometry to directly map the distributions of isotope-labeled cholesterol and sphingolipids in the plasma membranes of intact fibroblast cells. Although acute cholesterol depletion reduced sphingolipid domain abundance, cholesterol was evenly distributed throughout the plasma membrane and was not enriched within the sphingolipid domains. Thus, we rule out favorable cholesterol-sphingolipid interactions as dictating plasma membrane organization in fibroblast cells. Because the sphingolipid domains are disrupted by drugs that depolymerize the cells actin cytoskeleton, cholesterol must instead affect the sphingolipid organization via an indirect mechanism that involves the cytoskeleton. PMID:23609440

  2. Fibroblasts Cultured on Nanowires Exhibit Low Motility, Impaired Cell Division, and DNA Damage

    PubMed Central

    Persson, Henrik; Købler, Carsten; Mølhave, Kristian; Samuelson, Lars; Tegenfeldt, Jonas O; Oredsson, Stina; Prinz, Christelle N

    2013-01-01

    Nanowires are commonly used as tools for interfacing living cells, acting as biomolecule-delivery vectors or electrodes. It is generally assumed that the small size of the nanowires ensures a minimal cellular perturbation, yet the effects of nanowires on cell migration and proliferation remain largely unknown. Fibroblast behaviour on vertical nanowire arrays is investigated, and it is shown that cell motility and proliferation rate are reduced on nanowires. Fibroblasts cultured on long nanowires exhibit failed cell division, DNA damage, increased ROS content and respiration. Using focused ion beam milling and scanning electron microscopy, highly curved but intact nuclear membranes are observed, showing no direct contact between the nanowires and the DNA. The nanowires possibly induce cellular stress and high respiration rates, which trigger the formation of ROS, which in turn results in DNA damage. These results are important guidelines to the design and interpretation of experiments involving nanowire-based transfection and electrical characterization of living cells. PMID:23813871

  3. Sphingolipid domains in the plasma membranes of fibroblasts are not enriched with cholesterol

    DOE PAGES

    Frisz, Jessica F.; Klitzing, Haley A.; Lou, Kaiyan; ...

    2013-04-22

    The plasma membranes of mammalian cells are widely expected to contain domains that are enriched with cholesterol and sphingolipids. In this work, we have used high-resolution secondary ion mass spectrometry to directly map the distributions of isotope-labeled cholesterol and sphingolipids in the plasma membranes of intact fibroblast cells. Although acute cholesterol depletion reduced sphingolipid domain abundance, cholesterol was evenly distributed throughout the plasma membrane and was not enriched within the sphingolipid domains. As a result, we rule out favorable cholesterol-sphingolipid interactions as dictating plasma membrane organization in fibroblast cells. Because the sphingolipid domains are disrupted by drugs that depolymerize themore » cells actin cytoskeleton, cholesterol must instead affect the sphingolipid organization via an indirect mechanism that involves the cytoskeleton.« less

  4. Inhibition of cholesteryl ester formation in human fibroblasts by an analogue of 7-ketocholesterol and by progesterone

    PubMed Central

    Goldstein, Joseph L.; Faust, Jerry R.; Dygos, John H.; Chorvat, Robert J.; Brown, Michaels S.

    1978-01-01

    The synthesis of cholesteryl esters in cultured human fibroblasts is catalyzed by a microsomal acyl-coenzyme A:cholesterol acyltransferase (EC 2.3.1.26). The acyltransferase activity is enhanced when fibroblasts take up cholesterol contained in plasma low density lipoprotein. In the current studies two steroids, SC-31769 (an analogue of 7-ketocholesterol) and progesterone, were shown to inhibit acyltransferase activity in cell-free extracts of human fibroblasts. When added to intact cells, these steroids inhibited the incorporation of [14C]oleate into cellular cholesteryl [14C]oleate and reduced the accumulation of cholesteryl esters in fibroblasts exposed to low density lipoprotein. The inhibition of cholesteryl ester formation in intact cells by SC-31769 and progesterone was readily reversible. Neither compound inhibited the incorporation of [14C]oleate into [14C]triglycerides or [14C]phospholipids. When incubated with fibroblast monolayers at a concentration of 1 μg/ml, SC-31769 suppressed the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase [mevalonate:NADP+ oxidoreductase (CoA-acylating); EC 1.1.1.34], the rate-controlling enzyme in cholesterol synthesis. In contrast, progesterone had no effect on 3-hydroxy-3-methylglutaryl coenzyme A reductase activity at concentrations as high as 25 μg/ml. The availability of two types of steroid compounds that inhibit the acyltransferase activity and cholesteryl ester synthesis in human fibroblasts should prove useful in further studies of the regulatory mechanisms responsible for cholesteryl ester accumulation in human cells under normal and pathologic conditions. PMID:205874

  5. Murine Dermal Fibroblast Isolation by FACS.

    PubMed

    Walmsley, Graham G; Maan, Zeshaan N; Hu, Michael S; Atashroo, David A; Whittam, Alexander J; Duscher, Dominik; Tevlin, Ruth; Marecic, Owen; Lorenz, H Peter; Gurtner, Geoffrey C; Longaker, Michael T

    2016-01-07

    Fibroblasts are the principle cell type responsible for secreting extracellular matrix and are a critical component of many organs and tissues. Fibroblast physiology and pathology underlie a spectrum of clinical entities, including fibroses in multiple organs, hypertrophic scarring following burns, loss of cardiac function following ischemia, and the formation of cancer stroma. However, fibroblasts remain a poorly characterized type of cell, largely due to their inherent heterogeneity. Existing methods for the isolation of fibroblasts require time in cell culture that profoundly influences cell phenotype and behavior. Consequently, many studies investigating fibroblast biology rely upon in vitro manipulation and do not accurately capture fibroblast behavior in vivo. To overcome this problem, we developed a FACS-based protocol for the isolation of fibroblasts from the dorsal skin of adult mice that does not require cell culture, thereby preserving the physiologic transcriptional and proteomic profile of each cell. Our strategy allows for exclusion of non-mesenchymal lineages via a lineage negative gate (Lin(-)) rather than a positive selection strategy to avoid pre-selection or enrichment of a subpopulation of fibroblasts expressing specific surface markers and be as inclusive as possible across this heterogeneous cell type.

  6. Functional melanocytes are readily reprogrammable from multilineage-differentiating stress-enduring (muse) cells, distinct stem cells in human fibroblasts.

    PubMed

    Tsuchiyama, Kenichiro; Wakao, Shohei; Kuroda, Yasumasa; Ogura, Fumitaka; Nojima, Makoto; Sawaya, Natsue; Yamasaki, Kenshi; Aiba, Setsuya; Dezawa, Mari

    2013-10-01

    The induction of melanocytes from easily accessible stem cells has attracted attention for the treatment of melanocyte dysfunctions. We found that multilineage-differentiating stress-enduring (Muse) cells, a distinct stem cell type among human dermal fibroblasts, can be readily reprogrammed into functional melanocytes, whereas the remainder of the fibroblasts do not contribute to melanocyte differentiation. Muse cells can be isolated as cells positive for stage-specific embryonic antigen-3, a marker for undifferentiated human embryonic stem cells, and differentiate into cells representative of all three germ layers from a single cell, while also being nontumorigenic. The use of certain combinations of factors induces Muse cells to express melanocyte markers such as tyrosinase and microphthalmia-associated transcription factor and to show positivity for the 3,4-dihydroxy-L-phenylalanine reaction. When Muse cell-derived melanocytes were incorporated into three-dimensional (3D) cultured skin models, they localized themselves in the basal layer of the epidermis and produced melanin in the same manner as authentic melanocytes. They also maintained their melanin production even after the 3D cultured skin was transplanted to immunodeficient mice. This technique may be applicable to the efficient production of melanocytes from accessible human fibroblasts by using Muse cells, thereby contributing to autologous transplantation for melanocyte dysfunctions, such as vitiligo.

  7. Epigenetic reprogramming induces the expansion of cord blood stem cells

    PubMed Central

    Chaurasia, Pratima; Gajzer, David C.; Schaniel, Christoph; D’Souza, Sunita; Hoffman, Ronald

    2014-01-01

    Cord blood (CB) cells that express CD34 have extensive hematopoietic capacity and rapidly divide ex vivo in the presence of cytokine combinations; however, many of these CB CD34+ cells lose their marrow-repopulating potential. To overcome this decline in function, we treated dividing CB CD34+ cells ex vivo with several histone deacetylase inhibitors (HDACIs). Treatment of CB CD34+ cells with the most active HDACI, valproic acid (VPA), following an initial 16-hour cytokine priming, increased the number of multipotent cells (CD34+CD90+) generated; however, the degree of expansion was substantially greater in the presence of both VPA and cytokines for a full 7 days. Treated CD34+ cells were characterized based on the upregulation of pluripotency genes, increased aldehyde dehydrogenase activity, and enhanced expression of CD90, c-Kit (CD117), integrin α6 (CD49f), and CXCR4 (CD184). Furthermore, siRNA-mediated inhibition of pluripotency gene expression reduced the generation of CD34+CD90+ cells by 89%. Compared with CB CD34+ cells, VPA-treated CD34+ cells produced a greater number of SCID-repopulating cells and established multilineage hematopoiesis in primary and secondary immune–deficient recipient mice. These data indicate that dividing CB CD34+ cells can be epigenetically reprogrammed by treatment with VPA so as to generate greater numbers of functional CB stem cells for use as transplantation grafts. PMID:24762436

  8. Mammalian Stem Cells Reprogramming in Response to Terahertz Radiation

    PubMed Central

    Kang, Sona; Phipps, M. Lisa; Alexandrov, Ludmil B.; Rasmussen, Kim Ø.; Bishop, Alan R.; Rosen, Evan D.; Martinez, Jennifer S.; Chen, Hou-Tong; Rodriguez, George; Alexandrov, Boian S.; Usheva, Anny

    2010-01-01

    We report that extended exposure to broad-spectrum terahertz radiation results in specific changes in cellular functions that are closely related to DNA-directed gene transcription. Our gene chip survey of gene expression shows that whereas 89% of the protein coding genes in mouse stem cells do not respond to the applied terahertz radiation, certain genes are activated, while other are repressed. RT-PCR experiments with selected gene probes corresponding to transcripts in the three groups of genes detail the gene specific effect. The response was not only gene specific but also irradiation conditions dependent. Our findings suggest that the applied terahertz irradiation accelerates cell differentiation toward adipose phenotype by activating the transcription factor peroxisome proliferator-activated receptor gamma (PPARG). Finally, our molecular dynamics computer simulations indicate that the local breathing dynamics of the PPARG promoter DNA coincides with the gene specific response to the THz radiation. We propose that THz radiation is a potential tool for cellular reprogramming. PMID:21209821

  9. Nitric oxide triggers a transient metabolic reprogramming in Arabidopsis

    PubMed Central

    León, José; Costa, Álvaro; Castillo, Mari-Cruz

    2016-01-01

    Nitric oxide (NO) regulates plant growth and development as well as responses to stress that enhanced its endogenous production. Arabidopsis plants exposed to a pulse of exogenous NO gas were used for untargeted global metabolomic analyses thus allowing the identification of metabolic processes affected by NO. At early time points after treatment, NO scavenged superoxide anion and induced the nitration and the S-nitrosylation of proteins. These events preceded an extensive though transient metabolic reprogramming at 6 h after NO treatment, which included enhanced levels of polyamines, lipid catabolism and accumulation of phospholipids, chlorophyll breakdown, protein and nucleic acid turnover and increased content of sugars. Accordingly, lipid-related structures such as root cell membranes and leaf cuticle altered their permeability upon NO treatment. Besides, NO-treated plants displayed degradation of starch granules, which is consistent with the increased sugar content observed in the metabolomic survey. The metabolic profile was restored to baseline levels at 24 h post-treatment, thus pointing up the plasticity of plant metabolism in response to nitroxidative stress conditions. PMID:27885260

  10. Ising Model Reprogramming of a Repeat Protein's Equilibrium Unfolding Pathway.

    PubMed

    Millership, C; Phillips, J J; Main, E R G

    2016-05-08

    Repeat proteins are formed from units of 20-40 aa that stack together into quasi one-dimensional non-globular structures. This modular repetitive construction means that, unlike globular proteins, a repeat protein's equilibrium folding and thus thermodynamic stability can be analysed using linear Ising models. Typically, homozipper Ising models have been used. These treat the repeat protein as a series of identical interacting subunits (the repeated motifs) that couple together to form the folded protein. However, they cannot describe subunits of differing stabilities. Here we show that a more sophisticated heteropolymer Ising model can be constructed and fitted to two new helix deletion series of consensus tetratricopeptide repeat proteins (CTPRs). This analysis, showing an asymmetric spread of stability between helices within CTPR ensembles, coupled with the Ising model's predictive qualities was then used to guide reprogramming of the unfolding pathway of a variant CTPR protein. The designed behaviour was engineered by introducing destabilising mutations that increased the thermodynamic asymmetry within a CTPR ensemble. The asymmetry caused the terminal α-helix to thermodynamically uncouple from the rest of the protein and preferentially unfold. This produced a specific, highly populated stable intermediate with a putative dimerisation interface. As such it is the first step in designing repeat proteins with function regulated by a conformational switch.

  11. Untranslated regions (UTRs) orchestrate translation reprogramming in cellular stress responses.

    PubMed

    Sajjanar, Basavaraj; Deb, Rajib; Raina, Susheel Kumar; Pawar, Sachin; Brahmane, Manoj P; Nirmale, Avinash V; Kurade, Nitin P; Manjunathareddy, Gundallahalli B; Bal, Santanu Kumar; Singh, Narendra Pratap

    2017-04-01

    Stress is the result of an organism's interaction with environmental challenges. Regulations of gene expression including translation modulations are critical for adaptation and survival under stress. Untranslated regions (UTRs) of the transcripts play significant roles in translation regulation and continue to raise many intriguing questions in our understanding of cellular stress physiology. IRES (Internal ribosome entry site) and uORF (upstream open reading frame) mediated alternative translation initiations are emerging as unique mechanisms. Recent studies have revealed novel means of mRNAs stabilization in stress granules and their reversible modifications. Differential regulation of select transcripts is possible by the interplay between the adenine/uridine-rich elements (AREs) in 3'UTR with their binding proteins (AUBP) and by microRNA-mediated effects. Coordination of these various mechanisms control translation and thereby enables appropriate responses to environmental stress. In this review, we focus on the role of sequence signatures both at 5' and 3'UTRs in translation reprogramming during cellular stress responses.

  12. Metabolic reprogramming: a new relevant pathway in adult adrenocortical tumors

    PubMed Central

    Longatto-Filho, Adhemar; Faria, André M.; Fragoso, Maria C. B. V.; Lovisolo, Silvana M.; Lerário, Antonio M.; Almeida, Madson Q.

    2015-01-01

    Adrenocortical carcinomas (ACCs) are complex neoplasias that may present unexpected clinical behavior, being imperative to identify new biological markers that can predict patient prognosis and provide new therapeutic options. The main aim of the present study was to evaluate the prognostic value of metabolism-related key proteins in adrenocortical carcinoma. The immunohistochemical expression of MCT1, MCT2, MCT4, CD147, CD44, GLUT1 and CAIX was evaluated in a series of 154 adult patients with adrenocortical neoplasia and associated with patients' clinicopathological parameters. A significant increase in was found for membranous expression of MCT4, GLUT1 and CAIX in carcinomas, when compared to adenomas. Importantly MCT1, GLUT1 and CAIX expressions were significantly associated with poor prognostic variables, including high nuclear grade, high mitotic index, advanced tumor staging, presence of metastasis, as well as shorter overall and disease free survival. In opposition, MCT2 membranous expression was associated with favorable prognostic parameters. Importantly, cytoplasmic expression of CD147 was identified as an independent predictor of longer overall survival and cytoplasmic expression of CAIX as an independent predictor of longer disease-free survival. We provide evidence for a metabolic reprogramming in adrenocortical malignant tumors towards the hyperglycolytic and acid-resistant phenotype, which was associated with poor prognosis. PMID:26587828

  13. Reprogramming of plant cells by filamentous plant-colonizing microbes.

    PubMed

    Doehlemann, Gunther; Requena, Natalia; Schaefer, Patrick; Brunner, Frederic; O'Connell, Richard; Parker, Jane E

    2014-12-01

    Although phylogenetically unrelated, filamentous oomycetes and fungi establish similar structures to colonize plants and they represent economically the most important microbial threat to crop production. In mutualistic interactions established by root-colonizing fungi, clear differences to pathogens can be seen, but there is mounting evidence that their infection strategies and molecular interactions have certain common features. To infect the host, fungi and oomycetes employ similar strategies to circumvent plant innate immunity. This process involves the suppression of basal defence responses which are triggered by the perception of conserved molecular patterns. To establish biotrophy, effector proteins are secreted from mutualistic and pathogenic microbes to the host tissue, where they play central roles in the modulation of host immunity and metabolic reprogramming of colonized host tissues. This review article discusses key effector mechanisms of filamentous pathogens and mutualists, how they modulate their host targets and the fundamental differences or parallels between these different interactions. The orchestration of effector actions during plant infection and the importance of their localization within host tissues are also discussed.

  14. Reprogramming of circulatory cells in sepsis and SIRS.

    PubMed

    Cavaillon, J-M; Adrie, C; Fitting, C; Adib-Conquy, M

    2005-01-01

    Immune status is altered in patients with sepsis or non-infectious systemic inflammatory response syndrome (SIRS). Reduced ex-vivo TNF production by endotoxin-activated monocytes has been regularly reported. This observation is reminiscent of the phenomenon of endotoxin tolerance, and the term 'leukocyte reprogramming' well defines this phenomenon. This review will outline that the hyporesponsiveness of circulating leukocytes is not a generalized phenomenon in sepsis and SIRS. Indeed, the nature of the insult (i.e. infectious versus non-infectious SIRS; under anesthesia [surgery] or not [trauma, burn]), the nature of the activator used to trigger leukocytes (i.e. different Toll-like receptor ligands or whole bacteria), the nature of the cell culture (i.e. isolated monocytes versus peripheral blood mononuclear cells versus whole blood assays), and the nature of the analyzed cytokines (e.g. IL-1beta versus IL-1ra; TNF versus IL-10) have a profound influence on the outcome of the response.

  15. Metabolic Reprograming of Mononuclear Phagocytes in Progressive Multiple Sclerosis

    PubMed Central

    Tannahill, Gillian Margaret; Iraci, Nunzio; Gaude, Edoardo; Frezza, Christian; Pluchino, Stefano

    2015-01-01

    Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system (CNS). Accumulation of brain damage in progressive MS is partly the result of mononuclear phagocytes (MPs) attacking myelin sheaths in the CNS. Although there is no cure yet for MS, significant advances have been made in the development of disease modifying agents. Unfortunately, most of these drugs fail to reverse established neurological deficits and can have adverse effects. Recent evidence suggests that MPs polarization is accompanied by profound metabolic changes, whereby pro-inflammatory MPs (M1) switch toward glycolysis, whereas anti-inflammatory MPs (M2) become more oxidative. It is therefore possible that reprograming MPs metabolism could affect their function and repress immune cell activation. This mini review describes the metabolic changes underpinning macrophages polarization and anticipates how metabolic re-education of MPs could be used for the treatment of MS. Key points: Inflammation in progressive MS is mediated primarily by MPs.Cell metabolism regulates the function of MPs.DMAs can re-educate the metabolism of MPs to promote healing. PMID:25814990

  16. Dedifferentiation-reprogrammed mesenchymal stem cells with improved therapeutic potential.

    PubMed

    Liu, Yang; Jiang, Xiaohua; Zhang, Xiaohu; Chen, Rui; Sun, Tingting; Fok, Kin Lam; Dong, Jianda; Tsang, Lai Ling; Yi, Shaoqiong; Ruan, Yechun; Guo, Jinghui; Yu, Mei Kuen; Tian, Yuemin; Chung, Yiu Wa; Yang, Mo; Xu, Wenming; Chung, Chin Man; Li, Tingyu; Chan, Hsiao Chang

    2011-12-01

    Stem cell transplantation has been shown to improve functional outcome in degenerative and ischemic disorders. However, low in vivo survival and differentiation potential of the transplanted cells limits their overall effectiveness and thus clinical usage. Here we show that, after in vitro induction of neuronal differentiation and dedifferentiation, on withdrawal of extrinsic factors, mesenchymal stem cells (MSCs) derived from bone marrow, which have already committed to neuronal lineage, revert to a primitive cell population (dedifferentiated MSCs) retaining stem cell characteristics but exhibiting a reprogrammed phenotype distinct from their original counterparts. Of therapeutic interest, the dedifferentiated MSCs exhibited enhanced cell survival and higher efficacy in neuronal differentiation compared to unmanipulated MSCs both in vitro and in vivo, with significantly improved cognition function in a neonatal hypoxic-ischemic brain damage rat model. Increased expression of bcl-2 family proteins and microRNA-34a appears to be the important mechanism giving rise to this previously undefined stem cell population that may provide a novel treatment strategy with improved therapeutic efficacy.

  17. Ionizing Radiation Impairs T Cell Activation by Affecting Metabolic Reprogramming.

    PubMed

    Li, Heng-Hong; Wang, Yi-Wen; Chen, Renxiang; Zhou, Bin; Ashwell, Jonathan D; Fornace, Albert J

    2015-01-01

    Ionizing radiation has a variety of acute and long-lasting adverse effects on the immune system. Whereas measureable effects of radiation on immune cell cytotoxicity and population change have been well studied in human and animal models, little is known about the functional alterations of the surviving immune cells after ionizing radiation. The objective of this study was to delineate the effects of radiation on T cell function by studying the alterations of T cell receptor activation and metabolic changes in activated T cells isolated from previously irradiated animals. Using a global metabolomics profiling approach, for the first time we demonstrate that ionizing radiation impairs metabolic reprogramming of T cell activation, which leads to substantial decreases in the efficiency of key metabolic processes required for activation, such as glucose uptake, glycolysis, and energy metabolism. In-depth understanding of how radiation impacts T cell function highlighting modulation of metabolism during activation is not only a novel approach to investigate the pivotal processes in the shift of T cell homeostasis after radiation, it also may lead to new targets for therapeutic manipulation in the combination of radiotherapy and immune therapy. Given that appreciable effects were observed with as low as 10 cGy, our results also have implications for low dose environmental exposures.

  18. Epigenetic regulation of genetic integrity is reprogrammed during cloning.

    PubMed

    Murphey, Patricia; Yamazaki, Yukiko; McMahan, C Alex; Walter, Christi A; Yanagimachi, Ryuzo; McCarrey, John R

    2009-03-24

    Cloning by somatic cell nuclear transfer (SCNT) circumvents processes that normally function during gametogenesis to prepare the gamete genomes to support development of new progeny following fertilization. One such process is enhanced maintenance of genetic integrity in germ cells, such that germ cells typically carry fewer spontaneously acquired mutations than somatic cells in the same individual. Thus, embryos produced from somatic cells by SCNT could directly inherit more mutations than naturally conceived embryos. Alternatively, they could inherit epigenetic programming that predisposes more rapid accumulation of de novo mutations during development. We used a transgenic mouse system to test these possibilities by producing cloned midgestation mouse fetuses from three different donor somatic cell types carrying significantly different initial frequencies of spontaneous mutations. We found that on an individual locus basis, mutations acquired spontaneously in a population of donor somatic cells are not likely to be propagated to cloned embryos by SCNT. In addition, we found that the rate of accumulation of spontaneous mutations was similar in fetuses produced by either natural conception or cloning, indicating that cloned fetuses do not acquire mutations more rapidly than naturally conceived fetuses. These results represent the first direct demonstration that the process of cloning by SCNT does not lead to an increase in the frequency of point mutations. These results also demonstrate that epigenetic mechanisms normally contribute to the regulation of genetic integrity in a tissue-specific manner, and that these mechanisms are subject to reprogramming during cloning.

  19. Oligodendrocyte progenitor programming and reprogramming: Toward myelin regeneration.

    PubMed

    Lopez Juarez, Alejandro; He, Danyang; Richard Lu, Q

    2016-05-01

    Demyelinating diseases such as multiple sclerosis (MS) are among the most disabling and cost-intensive neurological disorders. The loss of myelin in the central nervous system, produced by oligodendrocytes (OLs), impairs saltatory nerve conduction, leading to motor and cognitive deficits. Immunosuppression therapy has a limited efficacy in MS patients, arguing for a paradigm shift to strategies that target OL lineage cells to achieve myelin repair. The inhibitory microenvironment in MS lesions abrogates the expansion and differentiation of resident OL precursor cells (OPCs) into mature myelin-forming OLs. Recent studies indicate that OPCs display a highly plastic ability to differentiate into alternative cell lineages under certain circumstances. Thus, understanding the mechanisms that maintain and control OPC fate and differentiation into mature OLs in a hostile, non-permissive lesion environment may open new opportunities for regenerative therapies. In this review, we will focus on 1) the plasticity of OPCs in terms of their developmental origins, distribution, and differentiation potentials in the normal and injured brain; 2) recent discoveries of extrinsic and intrinsic factors and small molecule compounds that control OPC specification and differentiation; and 3) therapeutic potential for motivation of neural progenitor cells and reprogramming of differentiated cells into OPCs and their likely impacts on remyelination. OL-based therapies through activating regenerative potentials of OPCs or cell replacement offer exciting opportunities for innovative strategies to promote remyelination and neuroprotection in devastating demyelinating diseases like MS. This article is part of a Special Issue entitled SI:NG2-glia(Invited only).

  20. Reprogramming cellular events by poly(ADP-ribose)-binding proteins

    PubMed Central

    Pic, Émilie; Ethier, Chantal; Dawson, Ted M.; Dawson, Valina L.; Masson, Jean-Yves; Poirier, Guy G.; Gagné, Jean-Philippe

    2013-01-01

    Poly(ADP-ribosyl)ation is a posttranslational modification catalyzed by the poly(ADP-ribose) polymerases (PARPs). These enzymes covalently modify glutamic, aspartic and lysine amino acid side chains of acceptor proteins by the sequential addition of ADP-ribose (ADPr) units. The poly(ADP-ribose) (pADPr) polymers formed alter the physico-chemical characteristics of the substrate with functional consequences on its biological activities. Recently, non-covalent binding to pADPr has emerged as a key mechanism to modulate and coordinate several intracellular pathways including the DNA damage response, protein stability and cell death. In this review, we describe the basis of non-covalent binding to pADPr that has led to the emerging concept of pADPr-responsive signaling pathways. This review emphasizes the structural elements and the modular strategies developed by pADPr-binding proteins to exert a fine-tuned control of a variety of pathways. Poly(ADP-ribosyl)ation reactions are highly regulated processes, both spatially and temporally, for which at least four specialized pADPr-binding modules accommodate different pADPr structures and reprogram protein functions. In this review, we highlight the role of well-characterized and newly discovered pADPr-binding modules in a diverse set of physiological functions. PMID:23268355

  1. Mitochondrial function in pluripotent stem cells and cellular reprogramming.

    PubMed

    Bukowiecki, Raul; Adjaye, James; Prigione, Alessandro

    2014-01-01

    Mitochondria are organelles playing pivotal roles in a range of diverse cellular functions, from energy generation to redox homeostasis and apoptosis regulation. Their loss of functionality may indeed contribute to the development of aging and age-related neurodegenerative disorders. Recently, mitochondria have been shown to exhibit peculiar features in pluripotent stem cells (PSCs). Moreover, an extensive restructuring of mitochondria has been observed during the process of cellular reprogramming, i.e. the conversion of somatic cells into induced pluripotent stem cells (iPSCs). These transformation events impact mitochondrial number, morphology, activity, cellular metabolism, and mtDNA integrity. PSCs retain the capability to self-renew indefinitely and to give rise to virtually any cell type of the body and thus hold great promise in medical research. Understanding the mitochondrial properties of PSCs, and how to modulate them, may thus help to shed light on the features of stemness and possibly increase our knowledge on cellular identity and differentiation pathways. Here, we review these recent findings and discuss their implications in the context of stem cell biology, aging research, and regenerative medicine.

  2. TRAF3 deficiency promotes metabolic reprogramming in B cells

    PubMed Central

    Mambetsariev, Nurbek; Lin, Wai W.; Wallis, Alicia M.; Stunz, Laura L.; Bishop, Gail A.

    2016-01-01

    The adaptor protein TNF receptor-associated factor 3 (TRAF3) is a critical regulator of B lymphocyte survival. B cell-specific TRAF3 deficiency results in enhanced viability and is associated with development of lymphoma and multiple myeloma. We show that TRAF3 deficiency led to induction of two proteins important for glucose metabolism, Glut1 and Hexokinase 2 (HXK2). This was associated with increased glucose uptake. In the absence of TRAF3, anaerobic glycolysis and oxidative phosphorylation were increased in B cells without changes in mitochondrial mass or reactive oxygen species. Chemical inhibition of glucose metabolism or glucose deprivation substantially attenuated the enhanced survival of TRAF3-deficient B cells, with a decrease in the pro-survival protein Mcl-1. Changes in Glut1 and Mcl-1 levels, glucose uptake and B cell number in the absence of TRAF3 were all dependent upon NF-κB inducing kinase (NIK). These results indicate that TRAF3 deficiency suffices to metabolically reprogram B cells, a finding that improves our understanding of the role of TRAF3 as a tumor suppressor, and suggests potential therapeutic strategies. PMID:27752131

  3. Reprogramming Postnatal Human Epidermal Keratinocytes toward Functional Neural Crest Fates.

    PubMed

    Bajpai, Vivek K; Kerosuo, Laura; Tseropoulos, Georgios; Cummings, Kirstie A; Wang, Xiaoyan; Lei, Pedro; Liu, Biao; Liu, Song; Popescu, Gabriela; Bronner, Marianne E; Andreadis, Stelios T

    2017-01-31

    During development, neural crest cells are induced by signaling events at the neural plate border of all vertebrate embryos. Initially arising within the central nervous system, neural crest cells subsequently undergo an epithelial to mesenchymal transition to migrate into the periphery, where they differentiate into diverse cell types. Here we provide evidence that postnatal human epidermal keratinocytes, in response to FGF2 and IGF1 signals, can be reprogrammed toward a neural crest fate. Genome-wide transcriptome analyses show that keratinocyte-derived neural crest cells are similar to those derived from human embryonic stem cells. Moreover, they give rise in vitro and in vivo to neural crest derivatives such as peripheral neurons, melanocytes, Schwann cells and mesenchymal cells (osteocytes, chondrocytes, adipocytes and smooth muscle). By demonstrating that human KRT14+ keratinocytes can form neural crest cells, even from clones of single cells, our results have important implications in stem cell biology and regenerative medicine. This article is protected by copyright. All rights reserved.

  4. Mouse cloning and somatic cell reprogramming using electrofused blastomeres.

    PubMed

    Riaz, Amjad; Zhao, Xiaoyang; Dai, Xiangpeng; Li, Wei; Liu, Lei; Wan, Haifeng; Yu, Yang; Wang, Liu; Zhou, Qi

    2011-05-01

    Mouse cloning from fertilized eggs can assist development of approaches for the production of "genetically tailored" human embryonic stem (ES) cell lines that are not constrained by the limitations of oocyte availability. However, to date only zygotes have been successfully used as recipients of nuclei from terminally differentiated somatic cell donors leading to ES cell lines. In fertility clinics, embryos of advanced embryonic stages are usually stored for future use, but their ability to support the derivation of ES cell lines via somatic nuclear transfer has not yet been proved. Here, we report that two-cell stage electrofused mouse embryos, arrested in mitosis, can support developmental reprogramming of nuclei from donor cells ranging from blastomeres to somatic cells. Live, full-term cloned pups from embryonic donors, as well as pluripotent ES cell lines from embryonic or somatic donors, were successfully generated from these reconstructed embryos. Advanced stage pre-implantation embryos were unable to develop normally to term after electrofusion and transfer of a somatic cell nucleus, indicating that discarded pre-implantation human embryos could be an important resource for research that minimizes the ethical concerns for human therapeutic cloning. Our approach provides an attractive and practical alternative to therapeutic cloning using donated oocytes for the generation of patient-specific human ES cell lines.

  5. Reprogramming the assembly of unmodified DNA with a small molecule

    NASA Astrophysics Data System (ADS)

    Avakyan, Nicole; Greschner, Andrea A.; Aldaye, Faisal; Serpell, Christopher J.; Toader, Violeta; Petitjean, Anne; Sleiman, Hanadi F.

    2016-04-01

    The ability of DNA to store and encode information arises from base pairing of the four-letter nucleobase code to form a double helix. Expanding this DNA ‘alphabet’ by synthetic incorporation of new bases can introduce new functionalities and enable the formation of novel nucleic acid structures. However, reprogramming the self-assembly of existing nucleobases presents an alternative route to expand the structural space and functionality of nucleic acids. Here we report the discovery that a small molecule, cyanuric acid, with three thymine-like faces, reprogrammes the assembly of unmodified poly(adenine) (poly(A)) into stable, long and abundant fibres with a unique internal structure. Poly(A) DNA, RNA and peptide nucleic acid (PNA) all form these assemblies. Our studies are consistent with the association of adenine and cyanuric acid units into a hexameric rosette, which brings together poly(A) triplexes with a subsequent cooperative polymerization. Fundamentally, this study shows that small hydrogen-bonding molecules can be used to induce the assembly of nucleic acids in water, which leads to new structures from inexpensive and readily available materials.

  6. Role of human pulp fibroblasts in angiogenesis.

    PubMed

    Tran-Hung, L; Mathieu, S; About, I

    2006-09-01

    After pulp amputation, complete pulp healing requires not only reparative dentin production but also fibroblast proliferation, nerve fiber growth, and neoangiogenesis. This study was designed to investigate the role of pulp fibroblasts in angiogenesis. Human pulp fibroblasts from third molars co-cultured with human umbilical vein endothelial cells induced the organization of endothelial cells and the formation of tubular structures corresponding to capillaries in vivo. The direct contact between both cells was not necessary to induce angiogenesis, and the observed effect was due to soluble factors. This was confirmed with neutralizing antibodies against FGF-2 and VEGF, which decreased the angiogenic effects of these soluble factors. Immunohistochemistry showed that both FGF-2 and VEGF were expressed in human dental pulp fibroblasts, and this expression increased after injury. These results suggest that the pulp fibroblasts secrete angiogenic factors, which are necessary for complete pulp healing, particularly at the pulp injury site.

  7. Cell-free production of transducible transcription factors for nuclear reprogramming

    PubMed Central

    Yang, William C.; Patel, Kedar G.; Lee, Jieun; Ghebremariam, Yohannes T.; Wong, H. Edward; Cooke, John P.; Swartz, James R.

    2011-01-01

    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 reprogramming factors 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 cell-free protein synthesis 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

  8. Reflectance Spectra Comparison of Orbital Debris, Intact Spacecraft, and Intact Rocket Bodies in the GEO Regime

    NASA Astrophysics Data System (ADS)

    Albercromby, Kira J.; Abell, Paul; Barker, Ed

    2009-03-01

    A key objective of NASA's Orbital Debris program office at Johnson Space Center (JSC) is to characterize the debris environment by way of assessing the physical properties (type, mass, density, and size) of objects in orbit. Knowledge of the geosynchronous orbit (GEO) debris environment in particular can be used to determine the hazard probability at specific GEO altitudes and aid predictions of the future environment. To calculate an optical size from an intensity measurement of an object in the GEO regime, a 0.175 albedo is assumed currently. However, identification of specific material type or types could improve albedo accuracy and yield a more accurate size estimate for the debris piece. Using spectroscopy, it is possible to determine the surface materials of space objects. The study described herein used the NASA Infrared Telescope Facility (IRTF) to record spectral data in the ~ 0.65 to 2.5 micron regime on eight catalogued space objects. For comparison, all of the objects observed were in GEO or near-GEO. The eight objects consisted of two intact spacecraft, three rocket bodies, and three catalogued debris pieces. Two of the debris pieces stemmed from Titan 3C transtage breakup and the third is from COSMOS 2054. The reflectance spectra of the Titan 3C pieces share similar slopes (increasing with wavelength) and lack any strong absorption features. The COSMOS debris spectrum has a slight slope and has no absorption features. In contrast, the intact spacecraft show classic absorption features due to solar cells with a strong band gap feature near 1 micron. The two spacecraft were spin-stabilized objects and therefore have solar panels surrounding the outer surface. Two of the three rocket bodies are inertial upper stage (IUS) rocket bodies and have similar looking spectra. The slopes flatten out near 1.5 microns with absorption features in the near-infrared that are similar to that of white paint. The third rocket body has a similar flattening of slope but

  9. Reflectance Spectra Comparison of Orbital Debris, Intact Spacecraft, and Intact Rocket Bodies in the GEO Regime

    NASA Technical Reports Server (NTRS)

    Barker, Ed; Abercromby, Kira J.; Abell, Paul

    2009-01-01

    A key objective of NASA s Orbital Debris program office at Johnson Space Center (JSC) is to characterize the debris environment by way of assessing the physical properties (type, mass, density, and size) of objects in orbit. Knowledge of the geosynchronous orbit (GEO) debris environment in particular can be used to determine the hazard probability at specific GEO altitudes and aid predictions of the future environment. To calculate an optical size from an intensity measurement of an object in the GEO regime, a 0.175 albedo is assumed currently. However, identification of specific material type or types could improve albedo accuracy and yield a more accurate size estimate for the debris piece. Using spectroscopy, it is possible to determine the surface materials of space objects. The study described herein used the NASA Infrared Telescope Facility (IRTF) to record spectral data in the 0.6 to 2.5 micron regime on eight catalogued space objects. For comparison, all of the objects observed were in GEO or near-GEO. The eight objects consisted of two intact spacecraft, three rocket bodies, and three catalogued debris pieces. Two of the debris pieces stemmed from Titan 3C transtage breakup and the third is from COSMOS 2054. The reflectance spectra of the Titan 3C pieces share similar slopes (increasing with wavelength) and lack any strong absorption features. The COSMOS debris spectra is flat and has no absorption features. In contrast, the intact spacecraft show classic absorption features due to solar panels with a strong band gap feature near 1 micron. The two spacecraft are spin-stabilized objects and therefore have solar panels surrounding the outer surface. Two of the three rocket bodies are inertial upper stage (IUS) rocket bodies and have similar looking spectra. The slopes flatten out near 1.5 microns with absorption features in the near-infrared that are similar to that of white paint. The third rocket body has a similar flattening of slope but with fewer

  10. Treatment for burn blisters: debride or leave intact?

    PubMed

    Murphy, Faye; Amblum, Jeshi

    2014-05-01

    This article presents findings from a systematic literature review of whether blisters arising from minor burns should be de-roofed or left intact. It discusses the risks of infection, healing outcomes, discomfort, choice of dressings and costs associated with each method, and reveals that debriding blisters larger than the patient's little fingernail while leaving smaller ones intact is generally agreed to be the best option. The article also explains external factors that influence the choice of whether to debride or leave blisters intact, reviews policy at the trust where one of the authors works in the context of the research and makes recommendations for practice.

  11. Inflammation and functional iron deficiency regulate fibroblast growth factor 23 production

    PubMed Central

    David, Valentin; Martin, Aline; Isakova, Tamara; Spaulding, Christina; Qi, Lixin; Ramirez, Veronica; Zumbrennen-Bullough, Kimberly B.; Sun, Chia Chi; Lin, Herbert Y.; Babitt, Jodie L.; Wolf, Myles

    2015-01-01

    Circulating levels of fibroblast growth factor 23 (FGF23) are elevated in patients with chronic kidney disease (CKD), but the mechanisms are poorly understood. Here we tested whether inflammation and iron deficiency regulate FGF23. In wild-type mice, acute inflammation induced by single injections of heat-killed Brucella abortus or interleukin-1β (IL-1β) decreased serum iron within 6 hours, and was accompanied by significant increases in osseous Fgf23 mRNA expression and serum levels of C-terminal FGF23, but no changes in intact FGF23. Chronic inflammation induced by repeated bacteria or IL-1β injections decreased serum iron, increased osseous Fgf23 mRNA and serum C-terminal FGF23, but modestly increased biologically active, intact FGF23 serum levels. Chronic iron deficiency mimicked chronic inflammation. Increased osseous FGF23 cleavage rather than a prolonged half-life of C-terminal FGF23 fragments accounted for the elevated C-terminal FGF23 but near-normal intact FGF23 levels in inflammation. IL-1β injection increased Fgf23 mRNA and C-terminal FGF23 levels similarly in wild-type and Col4a3KO mice with CKD, but markedly increased intact FGF23 levels only in the CKD mice. Inflammation increased Fgf23 transcription by activating Hif1α signaling. Thus, inflammation and iron deficiency stimulate FGF23 production. Simultaneous upregulation of FGF23 cleavage in osteocytes maintains near-normal levels of biologically active, intact circulating FGF23, whereas downregulated or impaired FGF23 cleavage may contribute to elevated intact serum FGF23 in CKD. PMID:26535997

  12. Inflammation and functional iron deficiency regulate fibroblast growth factor 23 production.

    PubMed

    David, Valentin; Martin, Aline; Isakova, Tamara; Spaulding, Christina; Qi, Lixin; Ramirez, Veronica; Zumbrennen-Bullough, Kimberly B; Sun, Chia Chi; Lin, Herbert Y; Babitt, Jodie L; Wolf, Myles

    2016-01-01

    Circulating levels of fibroblast growth factor 23 (FGF23) are elevated in patients with chronic kidney disease (CKD), but the mechanisms are poorly understood. Here we tested whether inflammation and iron deficiency regulate FGF23. In wild-type mice, acute inflammation induced by single injections of heat-killed Brucella abortus or interleukin-1β (IL-1β) decreased serum iron within 6 h, and was accompanied by significant increases in osseous Fgf23 mRNA expression and serum levels of C-terminal FGF23, but no changes in intact FGF23. Chronic inflammation induced by repeated bacteria or IL-1β injections decreased serum iron, increased osseous Fgf23 mRNA, and serum C-terminal FGF23, but modestly increased biologically active, intact FGF23 serum levels. Chronic iron deficiency mimicked chronic inflammation. Increased osseous FGF23 cleavage rather than a prolonged half-life of C-terminal FGF23 fragments accounted for the elevated C-terminal FGF23 but near-normal intact FGF23 levels in inflammation. IL-1β injection increased Fgf23 mRNA and C-terminal FGF23 levels similarly in wildtype and Col4a3(ko) mice with CKD but markedly increased intact FGF23 levels only in the CKD mice. Inflammation increased Fgf23 transcription by activating Hif1α signaling. Thus, inflammation and iron deficiency stimulate FGF23 production. Simultaneous upregulation of FGF23 cleavage in osteocytes maintains near-normal levels of biologically active, intact circulating FGF23, whereas downregulated or impaired FGF23 cleavage may contribute to elevated intact serum FGF23 in CKD.

  13. Induction of iPS cells and of cancer stem cells: the stem cell or reprogramming hypothesis of cancer?

    PubMed

    Trosko, James E

    2014-01-01

    This article as designed to examine whether the "stoichiometric" or "elite models" of the origin of the "induced pluripotent stem" (iPS) cells fits some experiment facts from the developmental biology of adult stem cells and from the field of cancer research. In brief, since the evidence presented to support the stoichiometric model failed to recognize the factual existence of adult organ specific stem cells, the model has not been rigorously tested. In addition, the demonstration of a subset of cells (MUSE cells) in normal primary in vitro cultures of human fibroblasts (the usual source of iPS cells) seems to be the origin of the iPS cells. Moreover, from the field of carcinogenesis, the "stem cell" versus "de-differentiation" or "reprogramming" hypotheses were examined. Again, using the role of glycolysis, known to be associated with the Warburg effect in cancer cells, a list of experiments showing that (a) normal stem cells, which have few mitochondria, metabolize via glycolysis; (b) the stem cells are targets for "initiation" or "immortalization" or the blockage of differentiation and apoptosis of the stem cells by "immortalizing viruses"; (c) Lactate dehydrogenase A (LDHA), when expressed, is associated with glycolysis and therefore, must be expressed in normal adult stem cells, as well as in cancer cells; and (d) p53, depleted or rendered dysfunctional by SV40 Large T antigen, is associated with the reduction of mitochondrial function and mass and is associated with the Warburg effect. Together, these observations from the iPS and "cancer stem cell" fields support the idea that both iPS cells and cancer stem cell are derived from adult organ-specific stem cells that do not restore or switch their metabolism of glucose from oxidative metabolism to glycolysis but, rather, in both cases, the adult stem cell, which metabolizes by glycolysis, is prevented from differentiation or from metabolizing by oxidative phosphorylation.

  14. 50 CFR 622.276 - Landing fish intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Dolphin and Wahoo Fishery Off the Atlantic States § 622.276 Landing fish intact. (a) Dolphin and wahoo in or...

  15. 50 CFR 622.276 - Landing fish intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Dolphin and Wahoo Fishery Off the Atlantic States § 622.276 Landing fish intact. (a) Dolphin and wahoo in or...

  16. 56. POWDER MAGAZINE, VIEW OF INTACT WOOD SHEATHING ON THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    56. POWDER MAGAZINE, VIEW OF INTACT WOOD SHEATHING ON THE SOUTHWEST REAR VENTILATION PASSAGE. (SHEATHING HELP CONTROL HUMIDITY AND DECREASE DANGER OF MAETAL STRIKING STONE AND SPARKING.) - Fort Monroe, Fortress, Hampton, Hampton, VA

  17. 50 CFR 622.247 - Landing golden crab intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ATLANTIC Golden Crab Fishery of the South Atlantic Region § 622.247 Landing golden crab intact. The... ashore. (a) A golden crab in or from the South Atlantic EEZ must be maintained in whole condition...

  18. 50 CFR 622.247 - Landing golden crab intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ATLANTIC Golden Crab Fishery of the South Atlantic Region § 622.247 Landing golden crab intact. The... ashore. (a) A golden crab in or from the South Atlantic EEZ must be maintained in whole condition...

  19. Acoustic emissions during deformation of intact and jointed welded tuff

    NASA Astrophysics Data System (ADS)

    Holcomb, D. J.; Teufel, L. W.

    1982-07-01

    Monitoring of acoustic emissions (AE) has been widely used as a means of detecting failure in intact rock. For intact rock the technique is simple, because an increasing rate of AE is usually a sign of impending failure. However, most large rock masses contain numerous joints and the behavior of the joints controls the properties of the rock mass In particular, the failure mode often becomes stable or unstable slip (stick-slip) on a joint at stresses well below those required for failure of the intact rock. As an aid to understanding and monitoring the behavior of jointed rock masses, we have done a series of experiments on intact and artificially jointed samples of Grouse Canyon tuff. The tuff was selected because it is under consideration as a disposal medium for nuclear wastes. The samples were instrumented to measure axial and transverse displacements and AE rates.

  20. Preparation of Cardiac Extracellular Matrix from an Intact Porcine Heart

    PubMed Central

    Wainwright, John M.; Czajka, Caitlin A.; Patel, Urvi B.; Freytes, Donald O.; Tobita, Kimimasa; Gilbert, Thomas W.

    2010-01-01

    Whole organ engineering would benefit from a three-dimensional scaffold produced from intact organ-specific extracellular matrix (ECM). The microenvironment and architecture provided by such a scaffold would likely support site-appropriate cell differentiation and spatial organization. The methods to produce such scaffolds from intact organs require customized decellularization protocols. In the present study, intact adult porcine hearts were successfully decellularized in less than 10 h using pulsatile retrograde aortic perfusion. Serial perfusion of an enzymatic, nonionic detergent, ionic detergent, and acid solution with hypotonic and hypertonic rinses was used to systematically remove cellular content. The resultant cardiac ECM retained collagen, elastin, and glycosaminoglycans, and mechanical integrity. Cardiac ECM supported the formation of organized chicken cardiomyocyte sarcomere structure in vitro. The intact decellularized porcine heart provides a tissue engineering template that may be beneficial for future preclinical studies and eventual clinical applications. PMID:19702513

  1. Preparation of cardiac extracellular matrix from an intact porcine heart.

    PubMed

    Wainwright, John M; Czajka, Caitlin A; Patel, Urvi B; Freytes, Donald O; Tobita, Kimimasa; Gilbert, Thomas W; Badylak, Stephen F

    2010-06-01

    Whole organ engineering would benefit from a three-dimensional scaffold produced from intact organ-specific extracellular matrix (ECM). The microenvironment and architecture provided by such a scaffold would likely support site-appropriate cell differentiation and spatial organization. The methods to produce such scaffolds from intact organs require customized decellularization protocols. In the present study, intact adult porcine hearts were successfully decellularized in less than 10 h using pulsatile retrograde aortic perfusion. Serial perfusion of an enzymatic, nonionic detergent, ionic detergent, and acid solution with hypotonic and hypertonic rinses was used to systematically remove cellular content. The resultant cardiac ECM retained collagen, elastin, and glycosaminoglycans, and mechanical integrity. Cardiac ECM supported the formation of organized chicken cardiomyocyte sarcomere structure in vitro. The intact decellularized porcine heart provides a tissue engineering template that may be beneficial for future preclinical studies and eventual clinical applications.

  2. cAMP and EPAC Signaling Functionally Replace OCT4 During Induced Pluripotent Stem Cell Reprogramming.

    PubMed

    Fritz, Ashley L; Adil, Maroof M; Mao, Sunnie R; Schaffer, David V

    2015-05-01

    The advent of induced pluripotent stem cells--generated via the ectopic overexpression of reprogramming factors such as OCT4, SOX2, KLF4, and C-MYC (OSKM) in a differentiated cell type--has enabled groundbreaking research efforts in regenerative medicine, disease modeling, and drug discovery. Although initial studies have focused on the roles of nuclear factors, increasing evidence highlights the importance of signal transduction during reprogramming. By utilizing a quantitative, medium-throughput screen to initially identify signaling pathways that could potentially replace individual transcription factors during reprogramming, we initially found that several pathways--such as Notch, Smoothened, and cyclic AMP (cAMP) signaling--were capable of generating alkaline phosphatase positive colonies in the absence of OCT4, the most stringently required Yamanaka factor. After further investigation, we discovered that cAMP signal activation could functionally replace OCT4 to induce pluripotency, and results indicate that the downstream exchange protein directly activated by cAMP (EPAC) signaling pathway rather than protein kinase A (PKA) signaling is necessary and sufficient for this function. cAMP signaling may reduce barriers to reprogramming by contributing to downstream epithelial gene expression, decreasing mesenchymal gene expression, and increasing proliferation. Ultimately, these results elucidate mechanisms that could lead to new reprogramming methodologies and advance our understanding of stem cell biology.

  3. Cell Reprogramming Requires Silencing of a Core Subset of Polycomb Targets

    PubMed Central

    Fragola, Giulia; Cuomo, Alessandro; Blasimme, Alessandro; Gross, Fridolin; Signaroldi, Elena; Bucci, Gabriele; Sommer, Cesar; Pruneri, Giancarlo; Mazzarol, Giovanni; Bonaldi, Tiziana; Mostoslavsky, Gustavo; Casola, Stefano; Testa, Giuseppe

    2013-01-01

    Transcription factor (TF)–induced reprogramming of somatic cells into induced pluripotent stem cells (iPSC) is associated with genome-wide changes in chromatin modifications. Polycomb-mediated histone H3 lysine-27 trimethylation (H3K27me3) has been proposed as a defining mark that distinguishes the somatic from the iPSC epigenome. Here, we dissected the functional role of H3K27me3 in TF–induced reprogramming through the inactivation of the H3K27 methylase EZH2 at the onset of reprogramming. Our results demonstrate that surprisingly the establishment of functional iPSC proceeds despite global loss of H3K27me3. iPSC lacking EZH2 efficiently silenced the somatic transcriptome and differentiated into tissues derived from the three germ layers. Remarkably, the genome-wide analysis of H3K27me3 in Ezh2 mutant iPSC cells revealed the retention of this mark on a highly selected group of Polycomb targets enriched for developmental regulators controlling the expression of lineage specific genes. Erasure of H3K27me3 from these targets led to a striking impairment in TF–induced reprogramming. These results indicate that PRC2-mediated H3K27 trimethylation is required on a highly selective core of Polycomb targets whose repression enables TF–dependent cell reprogramming. PMID:23468641

  4. Reprogramming of two somatic nuclei in the same ooplasm leads to pluripotent embryonic stem cells.

    PubMed

    Pfeiffer, Martin J; Esteves, Telma C; Balbach, Sebastian T; Araúzo-Bravo, Marcos J; Stehling, Martin; Jauch, Anna; Houghton, Franchesca D; Schwarzer, Caroline; Boiani, Michele

    2013-11-01

    The conversion of the nuclear program of a somatic cell from a differentiated to an undifferentiated state can be accomplished by transplanting its nucleus to an enucleated oocyte (somatic cell nuclear transfer [SCNT]) in a process termed "reprogramming." This process achieves pluripotency and occasionally also totipotency. Exploiting the obstacle of tetraploidy to full development in mammals, we show that mouse ooplasts transplanted with two somatic nuclei simultaneously (double SCNT) support preimplantation development and derivation of novel tetraploid SCNT embryonic stem cells (tNT-ESCs). Although the double SCNT embryos do not recapitulate the expression pattern of the pluripotency-associated gene Oct4 in fertilized embryos, derivative tNT-ESCs have characteristics of genuine pluripotency: in vitro they differentiate into neurons, cardiomyocytes, and endodermal cells; in vivo, tNT-ESCs form teratomas, albeit at reduced rates compared to diploid counterparts. Global transcriptome analysis revealed only few specific alterations, for example, in the quantitative expression of gastrulation-associated genes. In conclusion, we have shown that the oocyte's reprogramming capacity is in excess of a single nucleus and that double nucleus-transplanted embryos and derivative ESCs are very similar to their diploid counterparts. These results have key implications for reprogramming studies based on pluripotency: while reprogramming in the tetraploid state was known from fusion-mediated reprogramming and from fetal and adult hepatocyte-derived induced pluripotent stem cells, we have now accomplished it with enucleated oocytes.

  5. C/EBPα poises B cells for rapid reprogramming into induced pluripotent stem cells.

    PubMed

    Di Stefano, Bruno; Sardina, Jose Luis; van Oevelen, Chris; Collombet, Samuel; Kallin, Eric M; Vicent, Guillermo P; Lu, Jun; Thieffry, Denis; Beato, Miguel; Graf, Thomas

    2014-02-13

    CCAAT/enhancer binding protein-α (C/EBPα) induces transdifferentiation of B cells into macrophages at high efficiencies and enhances reprogramming into induced pluripotent stem (iPS) cells when co-expressed with the transcription factors Oct4 (Pou5f1), Sox2, Klf4 and Myc (hereafter called OSKM). However, how C/EBPα accomplishes these effects is unclear. Here we find that in mouse primary B cells transient C/EBPα expression followed by OSKM activation induces a 100-fold increase in iPS cell reprogramming efficiency, involving 95% of the population. During this conversion, pluripotency and epithelial-mesenchymal transition genes become markedly upregulated, and 60% of the cells express Oct4 within 2 days. C/EBPα acts as a 'path-breaker' as it transiently makes the chromatin of pluripotency genes more accessible to DNase I. C/EBPα also induces the expression of the dioxygenase Tet2 and promotes its translocation to the nucleus where it binds to regulatory regions of pluripotency genes that become demethylated after OSKM induction. In line with these findings, overexpression of Tet2 enhances OSKM-induced B-cell reprogramming. Because the enzyme is also required for efficient C/EBPα-induced immune cell conversion, our data indicate that Tet2 provides a mechanistic link between iPS cell reprogramming and B-cell transdifferentiation. The rapid iPS reprogramming approach described here should help to fully elucidate the process and has potential clinical applications.

  6. Direct cellular reprogramming in Caenorhabditis elegans: facts, models, and promises for regenerative medicine.

    PubMed

    Zuryn, Steven; Daniele, Thomas; Jarriault, Sophie

    2012-01-01

    In vitro systems of cellular reprogramming [induced pluripotent stem (iPS) cells and direct reprogramming or transdifferentiation] are rapidly improving our repertoire of molecular techniques that can force cells in culture to change into a desired identity. However, the new frontier for regenerative medicine is in vivo cellular reprogramming, which in light of concerns about the safety of in vitro cell manipulations, is an increasingly attractive approach for regenerative medicine. Powerful in vivo approaches are currently being undertaken in the genetic model Caenorhabditis elegans. Several very distinct cell types have been induced to change or have been discovered to transform naturally, into altogether different cell types. These examples have improved our understanding of the fundamental molecular and cellular mechanisms that permit cell identity changes in live animals. In addition, the combination of a stereotyped lineage with single cell analyses allows dissection of the early and intermediate mechanisms of reprogramming, as well as their kinetics. As a result, several important concepts on in vivo cellular reprogramming have been recently developed.

  7. Effects of Collective Histone State Dynamics on Epigenetic Landscape and Kinetics of Cell Reprogramming

    NASA Astrophysics Data System (ADS)

    Ashwin, S. S.; Sasai, Masaki

    2015-11-01

    Cell reprogramming is a process of transitions from differentiated to pluripotent cell states via transient intermediate states. Within the epigenetic landscape framework, such a process is regarded as a sequence of transitions among basins on the landscape; therefore, theoretical construction of a model landscape which exhibits experimentally consistent dynamics can provide clues to understanding epigenetic mechanism of reprogramming. We propose a minimal gene-network model of the landscape, in which each gene is regulated by an integrated mechanism of transcription-factor binding/unbinding and the collective chemical modification of histones. We show that the slow collective variation of many histones around each gene locus alters topology of the landscape and significantly affects transition dynamics between basins. Differentiation and reprogramming follow different transition pathways on the calculated landscape, which should be verified experimentally via single-cell pursuit of the reprogramming process. Effects of modulation in collective histone state kinetics on transition dynamics and pathway are examined in search for an efficient protocol of reprogramming.

  8. Reprogramming Müller glia via in vivo cell fusion regenerates murine photoreceptors

    PubMed Central

    Simonte, Giacoma; Di Vicino, Umberto; Romo, Neus; Pinilla, Isabel; Nicolás, Marta

    2016-01-01

    Vision impairments and blindness caused by retinitis pigmentosa result from severe neurodegeneration that leads to a loss of photoreceptors, the specialized light-sensitive neurons that enable vision. Although the mammalian nervous system is unable to replace neurons lost due to degeneration, therapeutic approaches to reprogram resident glial cells to replace retinal neurons have been proposed. Here, we demonstrate that retinal Müller glia can be reprogrammed in vivo into retinal precursors that then differentiate into photoreceptors. We transplanted hematopoietic stem and progenitor cells (HSPCs) into retinas affected by photoreceptor degeneration and observed spontaneous cell fusion events between Müller glia and the transplanted cells. Activation of Wnt signaling in the transplanted HSPCs enhanced survival and proliferation of Müller-HSPC hybrids as well as their reprogramming into intermediate photoreceptor precursors. This suggests that Wnt signaling drives the reprogrammed cells toward a photoreceptor progenitor fate. Finally, Müller-HSPC hybrids differentiated into photoreceptors. Transplantation of HSPCs with activated Wnt functionally rescued the retinal degeneration phenotype in rd10 mice, a model for inherited retinitis pigmentosa. Together, these results suggest that photoreceptors can be generated by reprogramming Müller glia and that this approach may have potential as a strategy for reversing retinal degeneration. PMID:27427986

  9. Effects of Collective Histone State Dynamics on Epigenetic Landscape and Kinetics of Cell Reprogramming

    PubMed Central

    Ashwin, S. S.; Sasai, Masaki

    2015-01-01

    Cell reprogramming is a process of transitions from differentiated to pluripotent cell states via transient intermediate states. Within the epigenetic landscape framework, such a process is regarded as a sequence of transitions among basins on the landscape; therefore, theoretical construction of a model landscape which exhibits experimentally consistent dynamics can provide clues to understanding epigenetic mechanism of reprogramming. We propose a minimal gene-network model of the landscape, in which each gene is regulated by an integrated mechanism of transcription-factor binding/unbinding and the collective chemical modification of histones. We show that the slow collective variation of many histones around each gene locus alters topology of the landscape and significantly affects transition dynamics between basins. Differentiation and reprogramming follow different transition pathways on the calculated landscape, which should be verified experimentally via single-cell pursuit of the reprogramming process. Effects of modulation in collective histone state kinetics on transition dynamics and pathway are examined in search for an efficient protocol of reprogramming. PMID:26581803

  10. Reprogramming MHC specificity by CRISPR-Cas9-assisted cassette exchange

    PubMed Central

    Kelton, William; Waindok, Ann Cathrin; Pesch, Theresa; Pogson, Mark; Ford, Kyle; Parola, Cristina; Reddy, Sai T.

    2017-01-01

    The development of programmable nucleases has enabled the application of new genome engineering strategies for cellular immunotherapy. While targeted nucleases have mostly been used to knock-out or knock-in genes in immune cells, the scarless exchange of entire immunogenomic alleles would be of great interest. In particular, reprogramming the polymorphic MHC locus could enable the creation of matched donors for allogeneic cellular transplantation. Here we show a proof-of-concept for reprogramming MHC-specificity by performing CRISPR-Cas9-assisted cassette exchange. Using murine antigen presenting cell lines (RAW264.7 macrophages), we demonstrate that the generation of Cas9-induced double-stranded breaks flanking the native MHC-I H2-Kd locus led to exchange of an orthogonal H2-Kb allele. MHC surface expression allowed for easy selection of reprogrammed cells by flow cytometry, thus obviating the need for additional selection markers. MHC-reprogrammed cells were fully functional as they could present H2-Kd-restricted peptide and activate cognate T cells. Finally, we investigated the role of various donor template formats on exchange efficiency, discovering that templates that underwent in situ linearization resulted in the highest MHC-reprogramming efficiency. These findings highlight a potential new approach for the correcting of MHC mismatches in cellular transplantation. PMID:28374766

  11. Transcriptional control of cardiac fibroblast plasticity.

    PubMed

    Lighthouse, Janet K; Small, Eric M

    2016-02-01

    Cardiac fibroblasts help maintain the normal architecture of the healthy heart and are responsible for scar formation and the healing response to pathological insults. Various genetic, biomechanical, or humoral factors stimulate fibroblasts to become contractile smooth muscle-like cells called myofibroblasts that secrete large amounts of extracellular matrix. Unfortunately, unchecked myofibroblast activation in heart disease leads to pathological fibrosis, which is a major risk factor for the development of cardiac arrhythmias and heart failure. A better understanding of the molecular mechanisms that control fibroblast plasticity and myofibroblast activation is essential to develop novel strategies to specifically target pathological cardiac fibrosis without disrupting the adaptive healing response. This review highlights the major transcriptional mediators of fibroblast origin and function in development and disease. The contribution of the fetal epicardial gene program will be discussed in the context of fibroblast origin in development and following injury, primarily focusing on Tcf21 and C/EBP. We will also highlight the major transcriptional regulatory axes that control fibroblast plasticity in the adult heart, including transforming growth factor β (TGFβ)/Smad signaling, the Rho/myocardin-related transcription factor (MRTF)/serum response factor (SRF) axis, and Calcineurin/transient receptor potential channel (TRP)/nuclear factor of activated T-Cell (NFAT) signaling. Finally, we will discuss recent strategies to divert the fibroblast transcriptional program in an effort to promote cardiomyocyte regeneration. This article is a part of a Special Issue entitled "Fibrosis and Myocardial Remodeling".

  12. Fibroblast migration in fibrin gel matrices.

    PubMed Central

    Brown, L. F.; Lanir, N.; McDonagh, J.; Tognazzi, K.; Dvorak, A. M.; Dvorak, H. F.

    1993-01-01

    In healing wounds and many solid tumors, locally increased microvascular permeability results in extravasation of fibrinogen and its extravascular coagulation to form a fibrin gel, with concomitant covalent cross-linking of fibrin by factor XIIIa. Subsequently, inflammatory cells, fibroblasts, and endothelial cells migrate into the gel and organize it into granulation tissue and later into mature collagenous connective tissue. To gain insight into some of the cell migration events associated with these processes, we developed a quantitative in vitro assay that permits the study of fibroblast migration in fibrin gels. Early passage human or rat fibroblasts were allowed to attach to tissue culture dishes and then were overlaid with a thin layer of fibrinogen that was clotted with thrombin. Fibroblasts began to migrate upwards into the fibrin within 24 hours and their numbers and the distance migrated were quantified over several days. The extent of fibroblast migration was affected importantly by the nature of the fibrin clot. Fibroblasts migrated optimally into gels prepared from fibrinogen at concentrations of -3 mg/ml; ie, near normal plasma fibrinogen levels. Migration was greatly enhanced by extensive cross-linking of the fibrin alpha-chains by factor XIIIa, as occurs when clotting takes place in vivo. When fibrinogen was clotted in Dulbecco's modified Eagle's medium, gamma-chains were cross-linked, but alpha-chain cross-linking was strikingly inhibited, and fibroblasts migrated poorly. Gels prepared from factor XIII-depleted fibrinogen exhibited neither alpha-nor gamma-chain cross-linking and did not support fibroblast migration. Further purification of fibrinogen by anion exchange high pressure liquid chromatography depleted fibrinogen of fibronectin, plasminogen, and other impurities; this purified fibrinogen clotted to form fibrin gels that supported reproducible fibroblast migration. Images Figure 1 Figure 2 Figure 4 Figure 6 PMID:8424460

  13. Platelet microparticles reprogram macrophage gene expression and function.

    PubMed

    Laffont, Benoit; Corduan, Aurélie; Rousseau, Matthieu; Duchez, Anne-Claire; Lee, Chan Ho C; Boilard, Eric; Provost, Patrick

    2016-01-01

    Platelet microparticles (MPs) represent the most abundant MPs subtype in the circulation, and can mediate intercellular communication through delivery of bioactives molecules, such as cytokines, proteins, lipids and RNAs. Here, we show that platelet MPs can be internalised by primary human macrophages and deliver functional miR-126-3p. The increase in macrophage miR-126-3p levels was not prevented by actinomycin D, suggesting that it was not due to de novo gene transcription. Platelet MPs dose-dependently downregulated expression of four predicted mRNA targets of miR-126-3p, two of which were confirmed also at the protein level. The mRNA downregulatory effects of platelet MPs were abrogated by expression of a neutralising miR-126-3p sponge, implying the involvement of miR-126-3p. Transcriptome-wide, microarray analyses revealed that as many as 66 microRNAs and 653 additional RNAs were significantly and differentially expressed in macrophages upon exposure to platelet MPs. More specifically, platelet MPs induced an upregulation of 34 microRNAs and a concomitant downregulation of 367 RNAs, including mRNAs encoding for cytokines/chemokines CCL4, CSF1 and TNF. These changes were associated with reduced CCL4, CSF1 and TNF cytokine/chemokine release by macrophages, and accompanied by a marked increase in their phagocytic capacity. These findings demonstrate that platelet MPs can modify the transcriptome of macrophages, and reprogram their function towards a phagocytic phenotype.

  14. Rational reprogramming of fungal polyketide first-ring cyclization

    PubMed Central

    Xu, Yuquan; Zhou, Tong; Zhou, Zhengfu; Su, Shiyou; Roberts, Sue A.; Montfort, William R.; Zeng, Jia; Chen, Ming; Zhang, Wei; Lin, Min; Zhan, Jixun; Molnár, István

    2013-01-01

    Resorcylic acid lactones and dihydroxyphenylacetic acid lactones represent important pharmacophores with heat shock response and immune system modulatory activities. The biosynthesis of these fungal polyketides involves a pair of collaborating iterative polyketide synthases (iPKSs): a highly reducing iPKS with product that is further elaborated by a nonreducing iPKS (nrPKS) to yield a 1,3-benzenediol moiety bridged by a macrolactone. Biosynthesis of unreduced polyketides requires the sequestration and programmed cyclization of highly reactive poly-β-ketoacyl intermediates to channel these uncommitted, pluripotent substrates to defined subsets of the polyketide structural space. Catalyzed by product template (PT) domains of the fungal nrPKSs and discrete aromatase/cyclase enzymes in bacteria, regiospecific first-ring aldol cyclizations result in characteristically different polyketide folding modes. However, a few fungal polyketides, including the dihydroxyphenylacetic acid lactone dehydrocurvularin, derive from a folding event that is analogous to the bacterial folding mode. The structural basis of such a drastic difference in the way a PT domain acts has not been investigated until now. We report here that the fungal vs. bacterial folding mode difference is portable on creating hybrid enzymes, and we structurally characterize the resulting unnatural products. Using structure-guided active site engineering, we unravel structural contributions to regiospecific aldol condensations and show that reshaping the cyclization chamber of a PT domain by only three selected point mutations is sufficient to reprogram the dehydrocurvularin nrPKS to produce polyketides with a fungal fold. Such rational control of first-ring cyclizations will facilitate efforts to the engineered biosynthesis of novel chemical diversity from natural unreduced polyketides. PMID:23509261

  15. Metabolic reprogramming induced by ketone bodies diminishes pancreatic cancer cachexia

    PubMed Central

    2014-01-01

    Background Aberrant energy metabolism is a hallmark of cancer. To fulfill the increased energy requirements, tumor cells secrete cytokines/factors inducing muscle and fat degradation in cancer patients, a condition known as cancer cachexia. It accounts for nearly 20% of all cancer-related deaths. However, the mechanistic basis of cancer cachexia and therapies targeting cancer cachexia thus far remain elusive. A ketogenic diet, a high-fat and low-carbohydrate diet that elevates circulating levels of ketone bodies (i.e., acetoacetate, β-hydroxybutyrate, and acetone), serves as an alternative energy source. It has also been proposed that a ketogenic diet leads to systemic metabolic changes. Keeping in view the significant role of metabolic alterations in cancer, we hypothesized that a ketogenic diet may diminish glycolytic flux in tumor cells to alleviate cachexia syndrome and, hence, may provide an efficient therapeutic strategy. Results We observed reduced glycolytic flux in tumor cells upon treatment with ketone bodies. Ketone bodies also diminished glutamine uptake, overall ATP content, and survival in multiple pancreatic cancer cell lines, while inducing apoptosis. A decrease in levels of c-Myc, a metabolic master regulator, and its recruitment on glycolytic gene promoters, was in part responsible for the metabolic phenotype in tumor cells. Ketone body-induced intracellular metabolomic reprogramming in pancreatic cancer cells also leads to a significantly diminished cachexia in cell line models. Our mouse orthotopic xenograft models further confirmed the effect of a ketogenic diet in diminishing tumor growth and cachexia. Conclusions Thus, our studies demonstrate that the cachectic phenotype is in part due to metabolic alterations in tumor cells, which can be reverted by a ketogenic diet, causing reduced tumor growth and inhibition of muscle and body weight loss. PMID:25228990

  16. Generation of HEXA-deficient hiPSCs from fibroblasts of a Tay-Sachs disease patient.

    PubMed

    Liu, Zhong; Zhao, Rui

    2016-09-01

    Human iPSC line TSD-01-hiPSC was generated from fibroblasts of a patient with infantile Tay-Sachs disease (TSD). The patient is compound heterozygous at the HEXA gene by carrying a 1278insTATC allele and an IVS12+1G>C allele. STEMCCA lentivirus, which expresses OCT4, SOX2, KLF4, and c-MYC from a polycistronic transcript, were used for reprogramming. TSD-01-hiPSC express pluripotency markers such as OCT4, SOX2, NANOG, Tra-1-60, and alkaline phosphatase, and can differentiate into tissues from all the three embryonic germ layers. This TSD patient-derived hiPSC line may serve as a valuable in vitro tool for disease modeling and drug test.

  17. Exogenous Expression of Human Protamine 1 (hPrm1) Remodels Fibroblast Nuclei into Spermatid-like Structures

    PubMed Central

    Iuso, Domenico; Czernik, Marta; Toschi, Paola; Fidanza, Antonella; Zacchini, Federica; Feil, Robert; Curtet, Sandrine; Buchou, Thierry; Shiota, Hitoshi; Khochbin, Saadi; Ptak, Grazyna Ewa; Loi, Pasqualino

    2015-01-01

    Summary Protamines confer a compact structure to the genome of male gametes. Here, we find that somatic cells can be remodeled by transient expression of protamine 1 (Prm1). Ectopically expressed Prm1 forms scattered foci in the nuclei of fibroblasts, which coalescence into spermatid-like structures, concomitant with a loss of histones and a reprogramming barrier, H3 lysine 9 methylation. Protaminized nuclei injected into enucleated oocytes efficiently underwent protamine to maternal histone TH2B exchange and developed into normal blastocyst stage embryos in vitro. Altogether, our findings present a model to study male-specific chromatin remodeling, which can be exploited for the improvement of somatic cell nuclear transfer. PMID:26628361

  18. Quantitative Proteomic Analysis of Mouse Embryonic Fibroblasts and Induced Pluripotent Stem Cells Using 16O /18O labeling

    SciTech Connect

    Huang, Xin; Tian, Changhai; Liu, Miao; Wang, Yongxiang; Tolmachev, Aleksey V.; Sharma, Seema; Yu, Fang; Fu, Kai; Zheng, Jialin; Ding, Shi-Jian

    2012-04-06

    Induced pluripotent stem cells (iPSC) hold great promise for regenerative medicine as well as for investigations into the pathogenesis and treatment of various diseases. Understanding of key intracellular signaling pathways and protein targets that control development of iPSC from somatic cells is essential for designing new approaches to improve reprogramming efficiency. Here we report the development and application of an integrated quantitative proteomics platform for investigating differences in protein expressions between mouse embryonic fibroblasts (MEF) and MEF-derived iPSC. This platform consists of 16O/18O labeling, multidimensional peptide separation coupled with tandem mass spectrometry, and data analysis with UNiquant software. Using this platform a total of 2,481 proteins were identified and quantified from the 16O/18O-labeled MEF-iPSC proteome mixtures with a false discovery rate of 0.01. Among them, 218 proteins were significantly upregulated, while 247 proteins were significantly downregulated in iPSC compared to MEF. Many nuclear proteins, including Hdac1, Dnmt1, Pcna, Ccnd1, Smarcc1, and subunits in DNA replication and RNA polymerase II complex were found to be enhanced in iPSC. Protein network analysis revealed that Pcna functions as a hub orchestrating complicated mechanisms including DNA replication, epigenetic inheritance (Dnmt1) and chromatin remodeling (Smarcc1) to reprogram MEF and maintain stemness of iPSC.

  19. Adhesion patterning by a novel air-lock technique enables localization and in-situ real-time imaging of reprogramming events in one-to-one electrofused hybrids

    PubMed Central

    Sakamoto, S.; Yamazaki, S.; Kurosawa, O.; Oana, H.; Kotera, H.; Washizu, M.

    2016-01-01

    Although fusion of somatic cells with embryonic stem (ES) cells has been shown to induce reprogramming, single-cell level details of the transitory phenotypic changes that occur during fusion-based reprogramming are still lacking. Our group previously reported on the technique of one-to-one electrofusion via micro-slits in a microfluidic platform. In this study, we focused on developing a novel air-lock patterning technique for creating localized adhesion zones around the micro-slits for cell localization and real-time imaging of post fusion events with a single-cell resolution. Mouse embryonic fibroblasts (MEF) were fused individually with mouse ES cells using a polydimethylsiloxane (PDMS) fusion chip consisting of two feeder channels with a separating wall containing an array of micro-slits (slit width ∼3 μm) at a regular spacing. ES cells and MEFs were introduced separately into the channels, juxtaposed on the micro-slits by dielectrophoresis and fused one-to-one by a pulse voltage. To localize fused cells for on-chip culture and time-lapse microscopy, we implemented a two-step approach of air-lock bovine serum albumin patterning and Matrigel coating to create localized adhesion areas around the micro-slits. As a result of time-lapse imaging, we could determine that cell division occurs within 24 h after fusion, much earlier than the 2–3 days reported by earlier studies. Remarkably, Oct4-GFP (Green Fluorescent Protein) was confirmed after 25 h of fusion and thereafter stably expressed by daughter cells of fused cells. Thus, integrated into our high-yield electrofusion platform, the technique of air-lock assisted adhesion patterning enables a single-cell level tracking of fused cells to highlight cell-level dynamics during fusion-based reprogramming. PMID:27822330

  20. Will cell reprogramming resolve the embryonic stem cell controversy? A narrative review.

    PubMed

    Power, Carl; Rasko, John E J

    2011-07-19

    In the past few years, relatively straightforward laboratory techniques have been developed to reprogram normal body cells to enter an embryonic stem cell-like state. Not only do these induced pluripotent stem cells hold great medical promise--perhaps greater than that of embryonic stem cells--but they also have escaped the ethical controversy in which the latter is mired. This article examines how cell reprogramming is likely to transform regenerative and reproductive medicine and highlights some of the medical, moral, and political hurdles that it faces. It also argues that induced pluripotent stem cells are more ethically problematic than most people believe and that cell reprogramming will not solve the stem cell controversy but complicate it further.

  1. A C. elegans LSD1 demethylase contributes to germline immortality by reprogramming epigenetic memory.

    PubMed

    Katz, David J; Edwards, T Matthew; Reinke, Valerie; Kelly, William G

    2009-04-17

    Epigenetic information undergoes extensive reprogramming in the germline between generations. This reprogramming may be essential to establish a developmental ground state in the zygote. We show that mutants in spr-5, the Caenorhabditis elegans ortholog of the H3K4me2 demethylase LSD1/KDM1, exhibit progressive sterility over many generations. This sterility correlates with the misregulation of spermatogenesis-expressed genes and transgenerational accumulation of the histone modification dimethylation of histone H3 on lysine 4 (H3K4me2). This suggests that H3K4me2 can serve as a stable epigenetic memory, and that erasure of H3K4me2 by LSD/KDM1 in the germline prevents the inappropriate transmission of this epigenetic memory from one generation to the next. Thus, our results provide direct mechanistic insights into the processes that are required for epigenetic reprogramming between generations.

  2. Global gene expression profiles reveal significant nuclear reprogramming by the blastocyst stage after cloning.

    PubMed

    Smith, Sadie L; Everts, Robin E; Tian, X Cindy; Du, Fuliang; Sung, Li-Ying; Rodriguez-Zas, Sandra L; Jeong, Byeong-Seon; Renard, Jean-Paul; Lewin, Harris A; Yang, Xiangzhong

    2005-12-06

    Nuclear transfer (NT) has potential applications in agriculture and biomedicine, but the technology is hindered by low efficiency. Global gene expression analysis of clones is important for the comprehensive study of nuclear reprogramming. Here, we compared global gene expression profiles of individual bovine NT blastocysts with their somatic donor cells and fertilized control embryos using cDNA microarray technology. The NT embryos' gene expression profiles were drastically different from those of their donor cells and closely resembled those of the naturally fertilized embryos. Our findings demonstrate that the NT embryos have undergone significant nuclear reprogramming by the blastocyst stage; however, problems may occur during redifferentiation for tissue genesis and organogenesis, and small reprogramming errors may be magnified downstream in development.

  3. Epigenetic reprogramming by somatic cell nuclear transfer: questions and potential solutions.

    PubMed

    Huili, Ji; Haosheng, Lu; Dengke, Pan

    2014-12-01

    Somatic cell nuclear transfer (SCNT) is a technology by which a highly differentiated somatic nucleus is transferred into an enucleated oocyte to generate a reconstructed embryo that subsequently develops to an offspring. However, to date, the efficiency of cloned animal is still low. The major reason is incomplete nuclear reprogramming of donor cells after nuclear transfer, which results in abnormal epigenetic modifications, including DNA methylation, histone acetylation, gene imprinting, X-chromosome inactivation, and telomere length. Most improvements have been made in somatic epigenetic reprogramming with small molecules and manipulating expression of specific genes. It is expected that SCNT will soon have broad applications in both basic research and practical production. In this review, we summarize the recent progress in epigenetic reprogramming by somatic cell nuclear transfer; in particular, we focus on strategies for rescuing the epigenetic errors occurring during SCNT.

  4. Expression profiling and pathway analysis of Krüppel-like factor 4 in mouse embryonic fibroblasts

    PubMed Central

    Hagos, Engda G; Ghaleb, Amr M; Kumar, Amrita; Neish, Andrew S; Yang, Vincent W

    2011-01-01

    Background: Krüppel-like factor 4 (KLF4) is a zinc-finger transcription factor with diverse regulatory functions in proliferation, differentiation, and development. KLF4 also plays a role in inflammation, tumorigenesis, and reprogramming of somatic cells to induced pluripotent stem (iPS) cells. To gain insight into the mechanisms by which KLF4 regulates these processes, we conducted DNA microarray analyses to identify differentially expressed genes in mouse embryonic fibroblasts (MEFs) wild type and null for Klf4. Methods: Expression profiles of fibroblasts isolated from mouse embryos wild type or null for the Klf4 alleles were examined by DNA microarrays. Differentially expressed genes were subjected to the Database for Annotation, Visualization and Integrated Discovery (DAVID). The microarray data were also interrogated with the Ingenuity Pathway Analysis (IPA) and Gene Set Enrichment Analysis (GSEA) for pathway identification. Results obtained from the microarray analysis were confirmed by Western blotting for select genes with biological relevance to determine the correlation between mRNA and protein levels. Results: One hundred and sixty three up-regulated and 88 down-regulated genes were identified that demonstrated a fold-change of at least 1.5 and a P-value < 0.05 in Klf4-null MEFs compared to wild type MEFs. Many of the up-regulated genes in Klf4-null MEFs encode proto-oncogenes, growth factors, extracellular matrix, and cell cycle activators. In contrast, genes encoding tumor suppressors and those involved in JAK-STAT signaling pathways are down-regulated in Klf4-null MEFs. IPA and GSEA also identified various pathways that are regulated by KLF4. Lastly, Western blotting of select target genes confirmed the changes revealed by microarray data. Conclusions: These data are not only consistent with previous functional studies of KLF4's role in tumor suppression and somatic cell reprogramming, but also revealed novel target genes that mediate KLF4's

  5. Cellular Ontogeny and Hierarchy Influence the Reprogramming Efficiency of Human B Cells into Induced Pluripotent Stem Cells.

    PubMed

    Muñoz-López, Álvaro; van Roon, Eddy H J; Romero-Moya, Damià; López-Millan, Belén; Stam, Ronald W; Colomer, Dolors; Nakanishi, Mahito; Bueno, Clara; Menendez, Pablo

    2016-03-01

    Although B cells have been shown to be refractory to reprogramming into pluripotency, induced pluripotent stem cells (iPSCs) have been very recently generated, at very low efficiency, from human cord blood (CB)- and peripheral blood (PB)-derived CD19+CD20 + B cells using nonintegrative tetracistronic OSKM-expressing Sendai Virus (SeV). Here, we addressed whether cell ontogeny and hierarchy influence the reprogramming efficiency of the B-cell compartment. We demonstrate that human fetal liver (FL)-derived CD19 + B cells are 110-fold easier to reprogram into iPSCs than those from CB/PB. Similarly, FL-derived CD34+CD19 + B progenitors are reprogrammed much easier than mature B cells (0.46% vs. 0.11%). All FL B-cell iPSCs carry complete VDJH rearrangements while 55% and 45% of the FL B-progenitor iPSCs carry incomplete and complete VDJH rearrangements, respectively, reflecting the reprogramming of developmentally different B progenitors (pro-B vs. pre-B) within a continuous differentiation process. Finally, our data suggest that successful B-cell reprogramming relies on active cell proliferation, and it is MYC-dependent as identical nonintegrative polycistronic SeV lacking MYC (OSKL or OSKLN) fail to reprogram B cells. The ability to efficiently reprogram human fetal primary B cells and B precursors offers an unprecedented opportunity for studying developmental B-lymphopoiesis and modeling B-cell malignances.

  6. MicroRNAs Induce Epigenetic Reprogramming and Suppress Malignant Phenotypes of Human Colon Cancer Cells

    PubMed Central

    Ogawa, Hisataka; Wu, Xin; Kawamoto, Koichi; Nishida, Naohiro; Konno, Masamitsu; Koseki, Jun; Matsui, Hidetoshi; Noguchi, Kozou; Gotoh, Noriko; Yamamoto, Tsuyoshi; Miyata, Kanjiro; Nishiyama, Nobuhiro; Nagano, Hiroaki; Yamamoto, Hirofumi; Obika, Satoshi; Kataoka, Kazunori; Doki, Yuichiro; Mori, Masaki; Ishii, Hideshi

    2015-01-01

    Although cancer is a genetic disease, epigenetic alterations are involved in its initiation and progression. Previous studies have shown that reprogramming of colon cancer cells using Oct3/4, Sox2, Klf4, and cMyc reduces cancer malignancy. Therefore, cancer reprogramming may be a useful treatment for chemo- or radiotherapy-resistant cancer cells. It was also reported that the introduction of endogenous small-sized, non-coding ribonucleotides such as microRNA (miR) 302s and miR-369-3p or -5p resulted in the induction of cellular reprogramming. miRs are smaller than the genes of transcription factors, making them possibly suitable for use in clinical strategies. Therefore, we reprogrammed colon cancer cells using miR-302s and miR-369-3p or -5p. This resulted in inhibition of cell proliferation and invasion and the stimulation of the mesenchymal-to-epithelial transition phenotype in colon cancer cells. Importantly, the introduction of the ribonucleotides resulted in epigenetic reprogramming of DNA demethylation and histone modification events. Furthermore, in vivo administration of the ribonucleotides in mice elicited the induction of cancer cell apoptosis, which involves the mitochondrial Bcl2 protein family. The present study shows that the introduction of miR-302s and miR-369s could induce cellular reprogramming and modulate malignant phenotypes of human colorectal cancer, suggesting that the appropriate delivery of functional small-sized ribonucleotides may open a new avenue for therapy against human malignant tumors. PMID:25970424

  7. Competence for Chemical Reprogramming of Sexual Fate Correlates with an Intersexual Molecular Signature in Caenorhabditis elegans

    PubMed Central

    Sorokin, Elena P.; Gasch, Audrey P.; Kimble, Judith

    2014-01-01

    In multicellular organisms, genetic programs guide cells to adopt cell fates as tissues are formed during development, maintained in adults, and repaired after injury. Here we explore how a small molecule in the environment can switch a genetic program from one fate to another. Wild-type Caenorhabditis elegans XX adult hermaphrodites make oocytes continuously, but certain mutant XX adults make sperm instead in an otherwise hermaphrodite soma. Thus, puf-8; lip-1 XX adults make only sperm, but they can be switched from sperm to oocyte production by treatment with a small-molecule MEK inhibitor. To ask whether this chemical reprogramming is common, we tested six XX sperm-only mutants, but found only one other capable of cell fate switching, fbf-1; lip-1. Therefore, reprogramming competence relies on genotype, with only certain mutants capable of responding to the MEK inhibitor with a cell fate change. To gain insight into the molecular basis of competence for chemical reprogramming, we compared polyadenylated transcriptomes of competent and noncompetent XX sperm-only mutants in the absence of the MEK inhibitor and hence in the absence of cell fate reprogramming. Despite their cellular production of sperm, competent mutants were enriched for oogenic messenger RNAs relative to mutants lacking competence for chemical reprogramming. In addition, competent mutants expressed the oocyte-specific protein RME-2, whereas those lacking competence did not. Therefore, mutants competent for reprogramming possess an intersexual molecular profile at both RNA and protein levels. We suggest that this intersexual molecular signature is diagnostic of an intermediate network state that poises the germline tissue for changing its cellular fate in response to environmental cues. PMID:25146970

  8. Competence for chemical reprogramming of sexual fate correlates with an intersexual molecular signature in Caenorhabditis elegans.

    PubMed

    Sorokin, Elena P; Gasch, Audrey P; Kimble, Judith

    2014-10-01

    In multicellular organisms, genetic programs guide cells to adopt cell fates as tissues are formed during development, maintained in adults, and repaired after injury. Here we explore how a small molecule in the environment can switch a genetic program from one fate to another. Wild-type Caenorhabditis elegans XX adult hermaphrodites make oocytes continuously, but certain mutant XX adults make sperm instead in an otherwise hermaphrodite soma. Thus, puf-8; lip-1 XX adults make only sperm, but they can be switched from sperm to oocyte production by treatment with a small-molecule MEK inhibitor. To ask whether this chemical reprogramming is common, we tested six XX sperm-only mutants, but found only one other capable of cell fate switching, fbf-1; lip-1. Therefore, reprogramming competence relies on genotype, with only certain mutants capable of responding to the MEK inhibitor with a cell fate change. To gain insight into the molecular basis of competence for chemical reprogramming, we compared polyadenylated transcriptomes of competent and noncompetent XX sperm-only mutants in the absence of the MEK inhibitor and hence in the absence of cell fate reprogramming. Despite their cellular production of sperm, competent mutants were enriched for oogenic messenger RNAs relative to mutants lacking competence for chemical reprogramming. In addition, competent mutants expressed the oocyte-specific protein RME-2, whereas those lacking competence did not. Therefore, mutants competent for reprogramming possess an intersexual molecular profile at both RNA and protein levels. We suggest that this intersexual molecular signature is diagnostic of an intermediate network state that poises the germline tissue for changing its cellular fate in response to environmental cues.

  9. Generation of induced pluripotent stem cells from buffalo (Bubalus bubalis) fetal fibroblasts with buffalo defined factors.

    PubMed

    Deng, Yanfei; Liu, Qingyou; Luo, Chan; Chen, Shibei; Li, Xiangping; Wang, Caizhu; Liu, Zhenzhen; Lei, Xiaocan; Zhang, Huina; Sun, Hongliang; Lu, Fenghua; Jiang, Jianrong; Shi, Deshun

    2012-09-01

    Ectopically, expression of defined factors could reprogram mammalian somatic cells into induced pluripotent stem cells (iPSCs), which initiates a new strategy to obtain pluripotent stem cell lines. Attempts have been made to generate buffalo pluripotent stem cells by culturing primary germ cells or inner cell mass, but the efficiency is extremely low. Here, we report a successful method to reprogram buffalo fetal fibroblasts (BFFs) into pluripotent stem cells [buffalo induced pluripotent stem cell (biPSCs)] by transduction of buffalo defined factors (Oct4, Sox2, Klf4, and c-Myc) using retroviral vectors. The established biPSCs displayed typical morphological characteristics of pluripotent stem cells, normal karyotype, positive staining of alkaline phosphatase, and expressed pluripotent markers including Oct4, Sox2, Nanog, Lin28, E-Cadherin, SSEA-1, SSEA-4, TRA-1-81, STAT3, and FOXD3. They could form embryoid bodies (EBs) in vitro and teratomas after injecting into the nude BALB/C mice, and 3 germ layers were identified in the EBs and teratomas. Methylation assay revealed that the promoters of Oct4 and Nanog were hypomethylated in biPSCs compared with BFFs and pre-biPSCs, while the promoters of Sox2 and E-Cadherin were hypomethylated in both BFFs and biPSCs. Further, inhibiting p53 expression by coexpression of SV40 large T antigen and buffalo defined factors in BFFs or treating BFFs with p53 inhibitor pifithrin-a (PFT) could increase the efficiency of biPSCs generation up to 3-fold, and nuclear transfer embryos reconstructed with biPSCs could develop to blastocysts. These results indicate that BFFs can be reprogrammed into biPSCs by buffalo defined factors, and the generation efficiency of biPSCs can be increased by inhibition of p53 expression. These efforts will provide a feasible approach for investigating buffalo stem cell signal pathways, establishing buffalo stem cell lines, and producing genetic modification buffaloes in the future.

  10. Human diploid fibroblasts have receptors for the globular domain of C1Q

    SciTech Connect

    Bordin, S.; Page, R.C.

    1986-03-01

    The authors showed that mass cultures of fibroblasts grown from gingival explants in DB medium with 10% human serum are enriched in a phenotype that binds C1q with an affinity much higher than the rest of the population. Because of potential biologic importance of C1q receptors, the authors studied whether the interaction between C1q and this phenotype was mediated by the globular or collagenous domains of the molecule. Globular fragments were prepared by digesting C1q with collagenase, and collagenous fragments obtained after pepsin treatment. C1q binding on cells in suspension was determined by reaction with /sup 125/I-C1q as reported. Competition experiments were performed under conditions in which intact /sup 125/I-C1q binding saturated all available receptors. The results showed that collagenous fragments inhibited 20% of the /sup 125/I-C1q binding to high affinity receptors, whereas inhibition by globular fragments was 70%. Unlabeled intact C1q and collagen type 1 were used as controls, and inhibited 92% and 17% of C1q binding, respectively. These studies show that C1q interacts with the fibroblast phenotype expressing high affinity receptors through its globular domain. The authors suggest that at sites of trauma, native C1 may bind to the surface of these cells via the globular domain of C1q, and that this unique phenotype may play an important role in tissue repair.

  11. PROGRAMMING AND REPROGRAMMING CELLULAR AGE IN THE ERA OF INDUCED PLURIPOTENCY

    PubMed Central

    Studer, Lorenz; Vera, Elsa; Cornacchia, Daniela

    2015-01-01

    The ability to reprogram adult somatic cells back to pluripotency presents a powerful tool to study cell fate identity and model human disease. However the reversal of cellular age during reprogramming results in an embryonic-like state of induced pluripotent stem cells (iPSCs) and their derivatives, which presents specific challenges for modeling late onset disease. This age reset requires novel methods to mimic age-related changes, but also offers opportunities to study cellular rejuvenation in real time. Here, we discuss how iPSC research may transform studies of aging and enable the precise programming of cellular age in parallel to cell fate specification. PMID:26046759

  12. MicroRNA in Metabolic Re-Programming and Their Role in Tumorigenesis

    PubMed Central

    Tomasetti, Marco; Amati, Monica; Santarelli, Lory; Neuzil, Jiri

    2016-01-01

    The process of metabolic re-programing is linked to the activation of oncogenes and/or suppression of tumour suppressor genes, which are regulated by microRNAs (miRNAs). The interplay between oncogenic transformation-driven metabolic re-programming and modulation of aberrant miRNAs further established their critical role in the initiation, promotion and progression of cancer by creating a tumorigenesis-prone microenvironment, thus orchestrating processes of evasion to apoptosis, angiogenesis and invasion/migration, as well metastasis. Given the involvement of miRNAs in tumour development and their global deregulation, they may be perceived as biomarkers in cancer of therapeutic relevance. PMID:27213336

  13. Assessing iPSC reprogramming methods for their suitability in translational medicine.

    PubMed

    Rao, Mahendra S; Malik, Nasir

    2012-10-01

    The discovery of the ability to induce somatic cells to a pluripotent state through the overexpression of specific transcription factors has the potential to transform the ways in which pharmaceutical agents and cellular transplantation therapies are developed. Proper utilization of the technology to generate induced pluripotent stem cells (iPSCs) requires that researchers select the appropriate reprogramming method for generating iPSCs so that the resulting iPSCs can be transitioned towards clinical applications effectively. This article reviews all of the currently available reprogramming techniques with a focus on critiquing them on the basis of their utility in translational medicine.

  14. Perspective for special Gurdon issue for differentiation: can cell fusion inform nuclear reprogramming?

    PubMed

    Burns, David; Blau, Helen M

    2014-07-01

    Nuclear reprogramming was first shown to be possible by Sir John Gurdon over a half century ago. The process has been revolutionized by the production of induced pluripotent cells by overexpression of the four transcription factors discovered by Shinya Yamanaka, which now enables mammalian applications. Yet, reprogramming by a few transcription factors remains incomplete and inefficient, whether to pluripotent or differentiated cells. We propose that a better understanding of mechanistic insights based on developmental principles gained from heterokaryon studies may inform the process of directing cell fate, fundamentally and clinically.

  15. Smooth muscle differentiation in scleroderma fibroblastic cells.

    PubMed Central

    Sappino, A. P.; Masouyé, I.; Saurat, J. H.; Gabbiani, G.

    1990-01-01

    Using antibodies to alpha-smooth muscle actin and desmin on paraffin-embedded formalin-fixed tissue sections, the authors demonstrate that fibroblastic cells of localized and systemic scleroderma lesions express features of smooth muscle differentiation. Eleven of eleven skin specimens of systemic sclerosis patients and two of four skin specimens of localized scleroderma displayed the presence of fibroblasts expressing alpha-smooth muscle actin, a cell population that predominated in areas of prominent collagen deposition. A similar fibroblastic phenotype was found in the esophagus, the liver, and the lung specimens obtained from four patients who died of progressive systemic sclerosis. Immunostaining for desmin, performed on adjacent tissue sections, demonstrated that a minority of these fibroblastic cells present in skin and visceral lesions contained this protein. The authors' observations indicate that scleroderma fibroblasts are phenotypically related to the stromal cells previously identified in hypertrophic scars, fibromatoses, and desmoplasia; they might provide novel criteria for the characterization of scleroderma lesions and help to identify the factors responsible for phenotypic modulations in fibroblastic cells. Images Figure 1 Figure 2 Figure 3 PMID:1698026

  16. Serum fibroblast growth factor 23, serum iron and bone mineral density in premenopausal women.

    PubMed

    Imel, Erik A; Liu, Ziyue; McQueen, Amie K; Acton, Dena; Acton, Anthony; Padgett, Leah R; Peacock, Munro; Econs, Michael J

    2016-05-01

    Fibroblast growth factor 23 (FGF23) circulates as active protein and inactive fragments. Low iron status increases FGF23 gene expression, and iron deficiency is common. We hypothesized that in healthy premenopausal women, serum iron influences C-terminal and intact FGF23 concentrations, and that iron and FGF23 associate with bone mineral density (BMD). Serum iron, iron binding capacity, percent iron saturation, phosphorus, and other biochemistries were measured in stored fasting samples from healthy premenopausal white (n=1898) and black women (n=994), age 20-55years. Serum C-terminal and intact FGF23 were measured in a subset (1631 white and 296 black women). BMD was measured at the lumbar spine and femur neck. Serum phosphorus, calcium, alkaline phosphatase and creatinine were lower in white women than black women (p<0.001). Serum iron (p<0.0001) and intact FGF23 (p<0.01) were higher in white women. C-terminal FGF23 did not differ between races. Phosphorus correlated with intact FGF23 (white women, r=0.120, p<0.0001; black women r=0.163, p<0.01). However, phosphorus correlated with C-terminal FGF23 only in black women (r=0.157, p<0.01). Intact FGF23 did not correlate with iron. C-terminal FGF23 correlated inversely with iron (white women r=-0.134, p<0.0001; black women r=-0.188, p<0.01), having a steeper slope at iron <50mcg/dl than ≥50mcg/dl. Longitudinal changes in iron predicted changes in C-terminal FGF23. Spine BMD correlated with iron negatively (r=-0.076, p<0.01) in white women; femur neck BMD correlated with iron negatively (r=-0.119, p<0.0001) in black women. Both relationships were eliminated in weight-adjusted models. BMD did not correlate with FGF23. Serum iron did not relate to intact FGF23, but was inversely related to C-terminal FGF23. Intact FGF23 correlated with serum phosphorus. In weight-adjusted models, BMD was not related to intact FGF23, C-terminal FGF23 or iron. The influence of iron on FGF23 gene expression is not important in

  17. Acidosis induces reprogramming of cellular metabolism to mitigate oxidative stress

    PubMed Central

    2013-01-01

    redirected away from several other critical metabolic processes, including ribose and glutathione synthesis. These alterations lead to both a decrease in cellular proliferation and increased sensitivity to ROS. Collectively, these data reveal a role for p53 in cellular metabolic reprogramming under acidosis, in order to permit increased bioenergetic capacity and ROS neutralization. Understanding the metabolic adaptations that cancer cells make under acidosis may present opportunities to generate anti-tumor therapeutic agents that are more tumor-specific. PMID:24359630

  18. Vulnerability of ecosystems to climate change moderated by habitat intactness.

    PubMed

    Eigenbrod, Felix; Gonzalez, Patrick; Dash, Jadunandan; Steyl, Ilse

    2015-01-01

    The combined effects of climate change and habitat loss represent a major threat to species and ecosystems around the world. Here, we analyse the vulnerability of ecosystems to climate change based on current levels of habitat intactness and vulnerability to biome shifts, using multiple measures of habitat intactness at two spatial scales. We show that the global extent of refugia depends highly on the definition of habitat intactness and spatial scale of the analysis of intactness. Globally, 28% of terrestrial vegetated area can be considered refugia if all natural vegetated land cover is considered. This, however, drops to 17% if only areas that are at least 50% wilderness at a scale of 48×48 km are considered and to 10% if only areas that are at least 50% wilderness at a scale of 4.8×4.8 km are considered. Our results suggest that, in regions where relatively large, intact wilderness areas remain (e.g. Africa, Australia, boreal regions, South America), conservation of the remaining large-scale refugia is the priority. In human-dominated landscapes, (e.g. most of Europe, much of North America and Southeast Asia), focusing on finer scale refugia is a priority because large-scale wilderness refugia simply no longer exist. Action to conserve such refugia is particularly urgent since only 1 to 2% of global terrestrial vegetated area is classified as refugia and at least 50% covered by the global protected area network.

  19. Structural and molecular interrogation of intact biological systems

    PubMed Central

    Chung, Kwanghun; Wallace, Jenelle; Kim, Sung-Yon; Kalyanasundaram, Sandhiya; Andalman, Aaron S.; Davidson, Thomas J.; Mirzabekov, Julie J.; Zalocusky, Kelly A.; Mattis, Joanna; Denisin, Aleksandra K.; Pak, Sally; Bernstein, Hannah; Ramakrishnan, Charu; Grosenick, Logan; Gradinaru, Viviana; Deisseroth, Karl

    2014-01-01

    Obtaining high-resolution information from a complex system, while maintaining the global perspective needed to understand system function, represents a key challenge in biology. Here we address this challenge with a method (termed CLARITY) for the transformation of intact tissue into a nanoporous hydrogel-hybridized form (crosslinked to a three-dimensional network of hydrophilic polymers) that is fully assembled but optically transparent and macromolecule-permeable. Using mouse brains, we show intact-tissue imaging of long-range projections, local circuit wiring, cellular relationships, subcellular structures, protein complexes, nucleic acids and neurotransmitters. CLARITY also enables intact-tissue in situ hybridization, immunohistochemistry with multiple rounds of staining and de-staining in non-sectioned tissue, and antibody labelling throughout the intact adult mouse brain. Finally, we show that CLARITY enables fine structural analysis of clinical samples, including non-sectioned human tissue from a neuropsychiatric-disease setting, establishing a path for the transmutation of human tissue into a stable, intact and accessible form suitable for probing structural and molecular underpinnings of physiological function and disease. PMID:23575631

  20. Study of cultured fibroblasts in vivo using NMR

    SciTech Connect

    Karczmar, G.S.

    1984-01-01

    The goal of this thesis was to study the compartmentation of phosphorylated glycolytic intermediates in intact Chicken Embryo Fibroblasts (CEFs) using /sup 31/P NMR at 109 MHz. Because glycolysis is regulated differently in normal and virally transformed CEFs, NMR experiments were performed on both types of cells. A technique for maintaining functional cells at high densities in an NMR magnet is described. Signals were detected from cytoplasmic inorganic phosphate (P/sub i/), ATP, NAD, NADH, phosphorylcholine and phosphorylethanolamine. The effect of external glucose on cytoplasmic pools of phosphates was studied. However, experiments with /sup 32/P labelled P/sub i/ showed that as the concentration of glucose in the medium was increased, the amount of phosphate sequestered in the cells increased. They conclude that there is a pool of P/sub i/ which is not detected by high resolution of NMR and that the size of this pool increases as the rate of glycolysis increases. These effects were found only in cultured cells; the data for transformed and normal cells were similar. Longitudinal relaxation times of intracellular phosphates in normal, transformed, and primary CEFs were measured.