PROGRESS TOWARDS THE DERIVATION OF PORCINE INDUCED PLURIPOTENT STEM CELLS

2012 ◽  
Vol 24 (1) ◽  
pp. 284
Author(s):  
Stoyan Petkov ◽  
Zoltan Ivics ◽  
Heiner Niemann
Keyword(s):  
Transcription Factors ◽  
Somatic Cells ◽  
Cell Types ◽  
Sleeping Beauty ◽  
Embryoid Bodies ◽  
Large Animal Model ◽  
Large Animal ◽  
Fetal Fibroblasts ◽  
Induced Pluripotent ◽  
E Cadherin

Porcine induced pluripotent cells (iPSC) are considered an important large animal model for developing personalized stem cell therapies. Since the derivation of the first mouse and human iPSC, there have been relatively few reports regarding the reprogramming of pig somatic cells into pluripotency, exclusively with the use of transcription factors from human and mouse origin. To investigate whether using species-specific transcription factors would allow for an efficient reprogramming of porcine somatic cells, we have developed a Sleeping Beauty (SB) transposon system based on the porcine OCT4, SOX2, C-MYC, and KLF4 sequences and have tested it in the reprogramming of mouse and porcine fetal fibroblasts and pig EGC-like cells. Transfection of mouse embryonic fibroblasts with a multicistronic SB-tetO-pOCT4-F2A-pSOX2-T2A-pC-MYC-E2A-pKLF4-ires-Tomato vector resulted in the formation of iPSC colonies, which inactivated the exogenous transcription factors and upregulated their endogenous pluripotency genes. These cells maintained mESC-like morphology, formed embryoid bodies, and differentiated into different cell types in culture, including rhythmically contracting cardiac myocytes. In contrast, porcine fibroblasts and EGC-like cells transfected with the same transposon vector did not proliferate in culture and did not form any iPSC colonies. We then transfected these cells with multiple bi-cistronic vectors SB-Ef1a-pOCT4-ires-Tomato, SB-Ef1a-pSOX2-ires-Neo, SB-Ef1a-pC-MYC-ires-Puro, and SB-Ef1a-pKLF4-ires-Puro. As a result, both cell types formed multiple colonies with mouse ESC-like morphology. Clones established from individually picked colonies from transfected fetal fibroblasts maintained this morphology for 5-6 passages, after which they became flat and epithelial-like. They expressed endogenous SOX2, C-MYC, KLF4, and E-Cadherin, but not OCT4. At the same time, clones derived from EGC-like cells proliferated at accelerated rate and maintained their morphology for over 10 passages at the time of this writing. While the exogenous genes were expressed continuously during this period, the cells expressed also endogenous OCT4, SOX2, TERT, STELLA, TDH, and CHD1; however, C-MYC, KLF4, NANOG, and E-Cadherin expression was relatively low. These cells are currently being characterized for pluripotency. Despite the use of porcine transcription factors, the overall reprogramming of porcine cells appears to be still less efficient compared with mouse fibroblasts. Our results suggest that the species and tissue origin of the somatic cells may play a more important role in the reprogramming to pluripotency than the origin of the transcription factors used. In this respect, optimization of culture conditions may be necessary in order to allow for efficient and complete reprogramming of porcine somatic cells. This work is supported by a research grant by the Deutsche Forschungsgemeinschaft.

214 Different pluripotency maintenance supplements affect the reprogramming process and pluripotency state of bovine-induced pluripotent stem cells

2020 ◽  
Vol 32 (2) ◽  
pp. 235
Author(s):  
R. Botigelli ◽  
N. Pieri ◽  
B. Bessi ◽  
R. de Castro ◽  
K. Recchia ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Embryoid Body ◽  
Embryoid Bodies ◽  
Cell Reprogramming ◽  
Rt Pcr ◽  
Serum Replacement ◽  
Fetal Fibroblasts ◽  
Induced Pluripotent ◽  
Knockout Serum Replacement ◽  
Pluripotency Maintenance

After the emergence of induced cell reprogramming, achieved through the addition of Yamanaka transcription factors (Oct4, Sox2, Klf4, and cMyc; OSKM) to somatic cells, the number of studies regarding induction and maintenance of pluripotency has increased greatly. The success of bovine iPSCs (biPSCs) was first described by Summer et al. (2011 J. Anim. Sci. 89, 2708-2716; https://doi.org/10.2527/jas.2010-3666); however, investigations on the pluripotent state of biPSCs are still needed because different protocols and characterisation profiles have since been used. The aim of this study was to produce biPSC lines supplemented with different pluripotency maintenance agents to improve self-renewal and pluripotency maintenance. For that, bovine fetal (50 days) fibroblasts (3×104) were transduced with lentivirus harbouring mouse OSKM transcription factors. The cells were further cultured in reprogramming medium (Dulbecco's modified Eagle's medium/F12 KO and 20% KSR (knockout serum replacement)) supplemented with basic fibroblast growth factor (bFGF), leukemia inhibitory factor (LIF), bFGF+2i or LIF+2i (where 2i inhibitors are PD0325901 and CHIR99021). The capacity for cell reprogramming was analysed by colony formation and maintenance after manually and enzymatic passaging and alkaline phosphatase (AP) activity detection; additionally, pluripotency state was assessed by reverse transcription (RT)-PCR (pluripotency biomarkers: OCT4, NANOG, and SOX2; naïve state: STELLA, LIFr, and ESRRb; primed state: OTX2 and FGF5; and mouse (m)OSKM and invitro differentiation assay (embryoid body formation). Statistical analysis was performed using the JMP software (SAS Institute Inc.). All treatments were successful at generating colonies after 28 days of mOSKM transduction, with 32 colonies in bFGF (0.53% efficiency), 21 colonies in bFGF+2i (0.35% efficiency), 5 colonies in LIF (0.08% efficiency), and 3 colonies in LIF+2i (0.05% efficiency) treatments/groups. As an initial pluripotency test, all colonies were positive for AP activity at passage 3. The colonies were cultured for at least 25 passages (±200 days) except for those from the LIF+2i treatment, which were not able to remain viable after 15 passages. Gene expression analysis of the pluripotency (naïve and primed) biomarkers in biPSCs by RT-PCR revealed that colonies from the bFGF treatment were upregulated in NANOG, OCT4, (pluripotency biomarkers), and STELLA (naïve biomarker) (P<0.05) compared with bFGF+2i and LIF groups. There were no differences in expression of SOX2 (pluripotency biomarker gene) and naïve/primed biomarkers (OXT2, LIFr, and ESRRb) (P>0.05). Additionally, the relative abundance of mOSKM was not different between groups (P>0.05). For further pluripotency analysis, biPS colonies were tested for the invitro differentiation assay, and all colonies tested were able to form embryoid bodies. In conclusion, bovine fetal fibroblasts were successfully reprogrammed when using OSKM in all medium tested; however, LIF+2i treatment did not grow beyond 25 passages. Further tests should be performed to determine the pluripotency status of these biPSCs. We acknowledge FAPESP for funding (grant nos. 2012/50533-2, 2015/26816-5, and 2016/16841-2).

scholarly journals A mini review on production of pluripotency factors (Oct4, Sox2, Klf4 and c-Myc) through recombinant protein technology

2020 ◽  
Vol 5 (1) ◽  
pp. 1-4 ◽  
Author(s):  
David Septian Sumanto Marpaung ◽  
Ayu Oshin Yap Sinaga
Keyword(s):  
Stem Cells ◽  
Transcription Factors ◽  
Embryonic Stem Cells ◽  
Pluripotent Stem Cells ◽  
Ectopic Expression ◽  
Embryonic Stem ◽  
Cell Types ◽  
Induced Pluripotency ◽  
Pluripotency Factors ◽  
Induced Pluripotent

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

1 GENERATION OF A STABLE TRANSGENIC SWINE MODEL FOR CELL TRACKING AND CHROMOSOME DYNAMIC STUDIES

2016 ◽  
Vol 28 (2) ◽  
pp. 130
Author(s):  
R. Sper ◽  
S. Simpson ◽  
X. Zhang ◽  
B. Collins ◽  
J. Piedrahita
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Animal Model ◽  
Regenerative Medicine ◽  
Cancer Biology ◽  
Large Animal Model ◽  
Large Animal ◽  
Fetal Fibroblasts ◽  
Transgene Transmission

Transgenic pigs are an attractive research model in the field of translational research, regenerative medicine, and stem cell therapy due to their anatomic, genetic, and physiological similarities with humans. The development of a transgenic murine model with a fusion of green fluorescent protein (GFP) to histone 2B protein (H2B, protein of nucleosome core) resulted in an easier and more convenient method for tracking cell migration and engraftment levels after transplantation as well as a way to better understand the complexity of molecular regulation within cell cycle/division, cancer biology, and chromosome dynamics. Up to now the development of a stable transgenic large animal model expressing H2B-GFP has not been described. Our objective was to develop the first transgenic porcine H2B-GFP model via CRISPR-CAS9 mediated recombination and somatic cell nuclear transfer (SCNT). Porcine fetal fibroblasts were cotransfected with CRISPR-CAS9 designed to target the 3′ untranslated region of ACTB locus and a targeting vector containing 1Kb homology arms to ACTB flanking an IRES-H2B-GFP transgene. Four days after transfection GFP cells were fluorescence activated cell sorted. Single cell colonies were generated and analysed by PCR, and heterozygous colonies were used as donor cells for SCNT. The custom designed CRISPR-CAS9 knockin system demonstrated a 2.4% knockin efficiency. From positive cells, 119 SCNT embryos were generated and transferred to a recipient gilt resulting in three positive founder boars (P1 generation). Boars show normal fertility (pregnancies obtained via AI of wild type sows). Generated P1 clones were viable and fertile with a transgene transmission rate of 55.8% (in concordance with Mendel’s law upon chi-square test with P = 0.05). Intranuclear H2B-GFP expression was confirmed via fluorescence microscopy on 8-day in vitro cultured SCNT blastocysts and a variety of tissues (heart, kidney, brain, bladder, skeletal muscle, stomach, skin, and so on) and primary cultured cells (chondrocytes, bone marrow derived, adipocyte derived, neural stem cells, and so on) from P1 cloned boars and F1 42-day fetuses and viable piglets. In addition, chromosome segregation could be easily identified during cell cycle division in in vitro cultured stem cells. Custom designed CRISPR-CAS 9 are able to drive homologous recombination in the ACTB locus in porcine fetal fibroblasts, allowing the generation of the first described viable H2B-GFP porcine model via SCNT. Generated clones and F1 generation expressed H2B-GFP ubiquitously, and transgene transmission rates were with concordance of Mendel’s law. This novel large animal model represents an improved platform for regenerative medicine and chromosome dynamic and cancer biology studies.

329 FLOW CYTOMETRIC ANALYSIS OF SPERMATOZOA FROM REPORTER TRANSGENIC BOARS DERIVED BY PRECISION GENETIC ENGINEERING

2013 ◽  
Vol 25 (1) ◽  
pp. 312
Author(s):  
W. Garrels ◽  
S. Holler ◽  
N. Cleve ◽  
S. Klein ◽  
Z. Ivics ◽  
...  
Keyword(s):  
Germ Line ◽  
Flow Cytometric Analysis ◽  
Embryonic Stem ◽  
Sleeping Beauty ◽  
Large Animal Model ◽  
Large Animal ◽  
Reporter Protein ◽  
Cassette Exchange ◽  
Flow Cytometric

Recently, we produced 2 founder boars with a non-autonomous Sleeping Beauty (SB) system carrying 3 monomeric integrations of a Venus transposon cassette and showing transgene segregation during meiosis (Garrels et al. 2011 PLoS One 6, e27563). It was possible to show transmission of the reporter protein to fertilized oocytes by confocal microscopy. The aim of this study was to assess the suitability of different fluorophore reporters for in vivo labelling of pig spermatozoa. Therefore, we used Venus transposon fibroblasts from a F1 boar, which carry a single integration of the transposon cassette and used these fibroblasts for a Cre-mediated cassette exchange against an mCherry reporter. These cells were used for somatic cell nuclear transfer (SCNT) to derive a syngene clone cohort of boars, which differ only in the fluorophore reporter cDNAs (either Venus or mCherry). Importantly, this methodology did not request any antibiotic selection cassette and allows precise genetic modifications in a livestock species where no authentic embryonic stem cells are available (Garrels et al. 2012 Trends in Biotechnology 30, 386–393). A total of 8 male piglets carrying the Venus transposon, and 4 male piglets carrying the mCherry reporter were born. Three Venus boars and 2 mCherry boars were raised to sexual maturity, and ejaculated sperm was obtained with the help of a phantom. A detailed flow cytometric analysis revealed that the spermatozoa samples were specifically Venus or mCherry positive [Gallios, Beckmann Coulter, Krefeld, Germany; solid-state laser (488 nm; 22 mW), filter for green fluorescence (525 BP); filter for red fluorescence: (620/30)], respectively. In direct comparative measurements, the spermatozoa samples from transgenic boars (Venus and Cherry) and wildtype controls could be discriminated. Interestingly, spermatozoa were uniformly Venus- or mCherry-positive and gave a distinct fluorescence peak in flow-cytometric measurements. The monomeric transgenes were transmitted through the germ line according to Mendelian rules with the expected ratio of 50% transgenic and 50% nontransgenic piglets. Fluorescence microscopic analysis and Western blotting confirmed the uniform presence of Venus and mCherry in boar spermatozoa, respectively. This is the first characterisation of spermatozoa from a pig cohort carrying a targeted cassette exchange. This large animal model may help to elucidate the function of paternally transmitted components to fertilized oocytes.

308 Tet1 PLAYS IMPORTANT ROLES IN MAINTAINING CHARACTERIZATIONS OF PORCINE INDUCED PLURIPOTENT STEM CELLS

2013 ◽  
Vol 25 (1) ◽  
pp. 301
Author(s):  
A. R. Fan ◽  
K. Y. Ma ◽  
T. C. Zhao ◽  
P. P. An ◽  
B. Tang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Induced Pluripotent Stem Cells ◽  
Pluripotent Stem Cells ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Self Renewal ◽  
Qrt Pcr ◽  
Post Transfection ◽  
Fetal Fibroblasts ◽  
Induced Pluripotent

It was recently found that the ten-eleven-translocation (TET) family of Fe(II) and 2-oxoglutarate-dependent enzymes (Tet1/2/3) can oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), and thus promotes active demethylation of genomes. Tet1 is highly expressed in mouse embryonic stem cells (mESC) and has been demonstrated to involve in mESC maintenance. Here we used small interference RNA (siRNA) to transiently knockdown expression of Tet1 in porcine induced pluripotent stem cells (iPSC) in order to identify its functions. The fetal fibroblasts were isolated from a 30-day-old porcine fetus and induced into iPSC with defined transcription factors, namely Oct-4, Sox-2, Klf-4, and C-myc. The colonies appeared on Day 12 and were picked up on Day 14. These colonies had normal ES-like morphology and alkaline phosphatase activity. Specifically, they were positively stained for pluripotency-specific markers, including Oct4, Sox2, Nanog, Rex1, and SSEA1. When cultured in vitro, the cells formed embryoid bodies (EB), and all 3 germ layer markers (endoderm: AFP, alphaAT; mesoderm: BMP4, Enolase; ectoderm: GFAP, Neurod) were detected positively in EB. For siRNA transfections, iPSC from the colonies were transfected with 40 pmol of siRNA and 2 µL of Lipofectamine 2000 in 1 well of a 24-well plate. After transfection, iPSC were subjected to fluorescence-activated cell sorting to determine the fraction of FAM-positive cells in order to confirm transfection efficiency; the percentage of positive cells reached 48 ± 4.96. We observed obvious knockdown of Tet1 after short-term transfection of siRNA, and the knockdown efficiency was confirmed using qRT-PCR and immunofluorescence staining. Notably, knockdown of Tet1 resulted in morphological abnormality and loss of undifferentiated state of porcine iPSC. However, no obvious morphological changes were observed in the negative control (transfected with nonsense-siRNA), positive control (transfected with GAPDH-siRNA), or mock control (transfected with DEPC-treated water). To gain insight into the molecular mechanism underlying the self-renewal defect, we analysed the effects of Tet1 knockdown on the expression of key stem cell factors and differentiation markers of different embryonic layers using qRT-PCR. We found that knockdown of Tet1 resulted in downregulated expression of pluripotency-related genes, such as Lefty-2, Klf-2, and Sox-2 (the expression ratios of post-transfection to pre-transfection were 0.31 ± 0.21, 0.48 ± 0.072, and 0.65 ± 0.046, respectively), and upregulated expression of differentiation-related genes, including Pitx-2, Hand-1, Gata-6, and Lef-1 (the expression ratios of post-transfection to pre-transfection were 4.35 ± 1.36, 2.56 ± 0.68, 2.91 ± 1.47, and 2.33 ± 1.11, respectively). However, Oct-4, C-myc, Klf-4, and Nanog were not downregulated (the expression ratios of post-transfection to pre-transfection were 0.91 ± 0.15, 1.12 ± 0.26, 1.15 ± 0.21, and 1.08 ± 0.08, respectively). Taken together, Tet1 plays important roles in porcine iPSC self-renewal and characterization maintenance. This study was financed by National Basic Research Program of China (NO.2009CB941001).

Analysis of Viral Integration Sites in Human Induced Pluripotent Stem Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1485-1485
Author(s):  
Thomas Winkler ◽  
Amy R Cantelina ◽  
Jean-Yves Metais ◽  
Xiuli Xu ◽  
Anh-Dao Nguyen ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Gene Transfer ◽  
Cell Lines ◽  
Chromosomal Location ◽  
Somatic Cells ◽  
Ips Cells ◽  
Ips Cell ◽  
Integration Sites ◽  
Equity Ownership ◽  
Induced Pluripotent

Abstract Abstract 1485 Poster Board I-508 The recently discovered approach for the direct reprogramming of somatic cells into induced pluripotent stem (IPS) cells by expression of defined transcription factors may provide new approaches for regenerative medicine, gene therapy and drug screening. Successful reprogramming currently requires at least temporary expression of one to four different transcription factors (among Oct3/4, Sox2, Klf4, c-Myc, Nanog and Lin28) in the targeted cells. Non-viral based reprogramming technologies have been reported, but expression of the reprogramming factors after γ-retroviral or lentiviral gene transfer remains the most efficient and commonly used approach. Since the reprogramming frequency is consistently low in these studies, it has been speculated that gene activation or disruption via proviral integration sites (IS) may play a role in obtaining the pluripotent phenotype. Here we present for the first time an extensive analysis of the lentiviral integration profile in human IPS-cells. We analysed the IS of 8 IPS cell lines derived from either human fetal fibroblasts (IMR90) or newborn foreskin fibroblasts (FS) after lentiviral gene transfer of Oct4, Sox2, Nanog, and Lin28, using linear amplification-mediated PCR (LAM-PCR). With 5 to15 IS per individual IPS clone we identified a total of 78 independent IS. Finally we assigned 75 IS to a unique chromosomal location. In addition to LAM-PCR, we confirmed the total number of IS via Southern blot. Interestingly, in 6 of 8 IPS clones some of these IS were found in pairs, integrated into the same chromosomal location within 4 base pairs of each other. This integration pattern has not been detected in our previous analysis of 702 IS in rhesus macaques transplanted with CD34+ cells transduced with retroviral vectors. Of the 75 valid IS 53 (70.7%) could be mapped to a gene-coding region, 52 located in introns and 1 in an exon, annotated in a human reference sequence in the UCSC Genome Browser RefSeq Genes track. The different IPS-clones had no integration site in common. To investigate the impact of integration on the regulation of vector targeted genes we analyzed the mRNA expression profiles using available microarray data from these clones. Out of 46 evaluable genes only two (WDR66 and MYST2 in clone IMR90-2, p<0.0001) were significantly over-expressed. The expression of two genes in clone FS-1 (ACVR2A p=0.01, RAF1 p=0.02) and one in FS-2 (KIAA0528, p=0.03) was decreased compared to the expression data of all other clones combined. In summary our data suggest that efficient reprogramming of human somatic cells is not dependent on insertional activation or deactivation of specific genes or gene classes. Furthermore, identification of the insertion profile of the IPS cell clones IMR90-1 and -4 as well as FS-1 will be useful to other researchers using these cell lines distributed by the Wisconsin International Stem Cell (WISC) bank. Disclosures: Antosiewicz-Bourget: Cellular Dynamics International: Consultancy, Equity Ownership. Thomson: Cellular Dynamics International: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Dunbar: ASH: Honoraria.

scholarly journals An orthogonal differentiation platform for genomically programming stem cells, organoids, and bioprinted tissues

2020 ◽  
Author(s):  
Mark A. Skylar-Scott ◽  
Jeremy Y. Huang ◽  
Aric Lu ◽  
Alex H.M. Ng ◽  
Tomoya Duenki ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Pluripotent Stem Cells ◽  
Cell Types ◽  
Embryoid Bodies ◽  
One Pot ◽  
Neural Tissues ◽  
Induced Pluripotent ◽  
And Function ◽  
Matrix Free

AbstractSimultaneous differentiation of human induced pluripotent stem cells (hiPSCs) into divergent cell types offers a pathway to achieving tailorable cellular complexity, patterned architecture, and function in engineered human organoids and tissues. Recent transcription factor (TF) overexpression protocols typically produce only one cell type of interest rather than the multitude of cell types and structural organization found in native human tissues. Here, we report an orthogonal differentiation platform for genomically programming stem cells, organoids and bioprinted tissues with controlled composition and organization. To demonstrate this platform, we orthogonally differentiated endothelial cells and neurons from hiPSCs in a one-pot system containing neural stem cell-specifying media. By aggregating inducible-TF and wildtype hiPSCs into pooled and multicore-shell embryoid bodies, we produced vascularized and patterned cortical organoids within days. Using multimaterial 3D bioprinting, we patterned 3D neural tissues from densely cellular, matrix-free stem cell inks that were orthogonally differentiated on demand into distinct layered regions composed of neural stem cells, endothelium, and neurons, respectively. Given the high proliferative capacity and patient-specificity of hiPSCs, our platform provides a facile route for programming cells and multicellular tissues for drug screening and therapeutic applications.

scholarly journals Dot1L methyltransferase activity is a barrier to acquisition of pluripotency but not transdifferentiation

2019 ◽  
Author(s):  
Coral K. Wille ◽  
Rupa Sridharan
Keyword(s):  
Stem Cells ◽  
Cell Fate ◽  
Pluripotent Stem Cells ◽  
Somatic Cells ◽  
Cell Types ◽  
Transcriptional Elongation ◽  
Mrna Levels ◽  
Mesenchymal To Epithelial Transition ◽  
Ipsc Generation ◽  
Induced Pluripotent

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

scholarly journals Exogenous LIN28 Is Required for the Maintenance of Self-Renewal and Pluripotency in Presumptive Porcine-Induced Pluripotent Stem Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Warunya Chakritbudsabong ◽  
Somjit Chaiwattanarungruengpaisan ◽  
Ladawan Sariya ◽  
Sirikron Pamonsupornvichit ◽  
Joao N. Ferreira ◽  
...  
Keyword(s):  
Stem Cells ◽  
Alkaline Phosphatase ◽  
Induced Pluripotent Stem Cells ◽  
Pluripotent Stem Cells ◽  
Embryoid Bodies ◽  
Self Renewal ◽  
Fetal Fibroblasts ◽  
Induced Pluripotent

Porcine species have been used in preclinical transplantation models for assessing the efficiency and safety of transplants before their application in human trials. Porcine-induced pluripotent stem cells (piPSCs) are traditionally established using four transcription factors (4TF): OCT4, SOX2, KLF4, and C-MYC. However, the inefficiencies in the reprogramming of piPSCs and the maintenance of their self-renewal and pluripotency remain challenges to be resolved. LIN28 was demonstrated to play a vital role in the induction of pluripotency in humans. To investigate whether this factor is similarly required by piPSCs, the effects of adding LIN28 to the 4TF induction method (5F approach) on the efficiency of piPSC reprogramming and maintenance of self-renewal and pluripotency were examined. Using a retroviral vector, porcine fetal fibroblasts were transfected with human OCT4, SOX2, KLF4, and C-MYC with or without LIN28. The colony morphology and chromosomal stability of these piPSC lines were examined and their pluripotency properties were characterized by investigating both their expression of pluripotency-associated genes and proteins and in vitro and in vivo differentiation capabilities. Alkaline phosphatase assay revealed the reprogramming efficiencies to be 0.33 and 0.17% for the 4TF and 5TF approaches, respectively, but the maintenance of self-renewal and pluripotency until passage 40 was 6.67 and 100%, respectively. Most of the 4TF-piPSC colonies were flat in shape, showed weak positivity for alkaline phosphatase, and expressed a significantly high level of SSEA-4 protein, except for one cell line (VSMUi001-A) whose properties were similar to those of the 5TF-piPSCs; that is, tightly packed and dome-like in shape, markedly positive for alkaline phosphatase, and expressing endogenous pluripotency genes (pOCT4, pSOX2, pNANOG, and pLIN28), significantly high levels of pluripotent proteins (OCT4, SOX2, NANOG, LIN28, and SSEA-1), and a significantly low level of SSEA-4 protein. VSMUi001-A and all 5F-piPSC lines formed embryoid bodies, underwent spontaneous cardiogenic differentiation with cardiac beating, expressed cardiomyocyte markers, and developed teratomas. In conclusion, in addition to the 4TF, LIN28 is required for the effective induction of piPSCs and the maintenance of their long-term self-renewal and pluripotency toward the development of all germ layers. These piPSCs have the potential applicability for veterinary science.

5 DISRUPTION OF THE HIGH MOBILITY GROUP AT-HOOK 2 (HMGA2) GENE IN SWINE REDUCES POSTNATAL GROWTH

2014 ◽  
Vol 26 (1) ◽  
pp. 117 ◽  
Author(s):  
J. Chung ◽  
X. Zhang ◽  
B. Colins ◽  
K. Howard ◽  
S. Simpson ◽  
...  
Keyword(s):  
Cell Lines ◽  
Mutant Cell ◽  
High Mobility ◽  
Postnatal Growth ◽  
High Mobility Group ◽  
Large Animal Model ◽  
Large Animal ◽  
Wild Type ◽  
Adult Growth ◽  
Fetal Fibroblasts

The high mobility group AT-hook 2 (HMGA2) protein has been shown to be a crucial gene for cell growth, proliferation, and apoptosis; HMGA2 is also a strong biological candidate for growth, because mutations in this gene alter body size in mice and humans. Compared with wild-type controls, adult mice lacking HMGA2 are 60% smaller, and adult heterozygous mutants are 20% smaller. In humans, HMGA2 has been associated with adult and childhood height without any other deleterious effect. Additionally, a microdeletion in the HMGA2 gene in a human patient resulted in short stature, with no dysmorphologies and normal puberty. In order to determine the effect of HMGA2 on fetal and adult growth in pigs, a transgenic pig line deficient in HMGA2 expression was generated by gene targeting in fetal fibroblasts (FF). Using a targeting vector carrying a reporter gene, and homology arms specific to HMGA2, heterozygous mutant cell lines were generated. The cell lines were then used to generate 6 heterozygous females by somatic cell nuclear transfer (SCNT). Bodyweights and lengths from snout to base of tail were measured every 2 weeks for a year for mutant (n = 6) and wild-type farm gilts (n = 6). Data were analysed by one-way ANOVA. As in mice, disruption of one allele of the HMGA2 gene resulted in 25% reduction in weight (P < 0.0001) and 14% reduction in length (P < 0.0001). Early in postnatal growth (2 months), weights of mutants were not different than wild-type. However, mutants were 20 to 35% lighter (P < 0.05) during mid stages (6 months) and 25 to 30% (P < 0.0001) in late stages (3 months). The same insertional mutation generated 8 heterozygous male clones by SCNT. In addition, 7 nontransgenic males from the same FF line were generated as SCNT controls. Bodyweights and lengths were measured every 2 weeks for 30 weeks for HMGA2 heterozygous mutants (n = 8), control SCNT (n = 7) and wild-type farm boars (n = 5). The weight curve of boars showed similar pattern as for mutant gilts. At 30-week postnatal stage, mutants were 17% (P < 0.05) and 16% (P < 0.05) lighter in weight compared with littermate and wild-type animals, respectively. We are presently developing homozygous HMGA2 mutant lines. Currently, 3 of 6 heterozygous gilts have been bred with heterozygous boars, with 1 confirmed pregnancy. The expectation is that the homozygous animals will, like mice, be 60% smaller than the wild-type animals. The approach described here will result not only in a valuable large-animal model of dwarfism, but also in a tool to reduce the size of existing transgenic and nontransgenic swine lines. This, in turn, will increase the receptivity of valuable transgenic lines by the biomedical community. Funding for this work was provided by NIH grant R21-OD010553 to JP.

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