Can Fibroblasts Be Reprogrammed into Macrophages?.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 443-443
Author(s):  
Ru Feng ◽  
Thomas Graf
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Cell Lines ◽  
Fibroblast Cell ◽  
Bzip Transcription Factor ◽  
Nih3t3 Cells ◽  
Activation Domains ◽  
Gm Csf ◽  
Infected Cells ◽  
Factor C

Abstract Previous work showed that B cell precursors can be reprogrammed into functional macrophages by the enforced expression of the bZip transcription factor C/EBPalpha. The efficient activation of myelomonocytic genes, such as Mac-1, required the co-operation with endogenous PU.1 (Xie et al. 2004), reflecting the fact that many myelomonocytic genes are regulated by a combination of the two transcription factors. We therefore asked: Is C/EBPa and PU.1 sufficient to convert non-hematopoietic cells into macrophages? To test this, NIH-3T3 cells were co-infected with PU.1-GFP and C/EBPa-hCD4 retrovirusesor control vectors encoding the indicators GFP and hCD4 only. Uninfected cells in the retrovirus treated cultures served as additional controls. Our results showed that ~25% of the PU.1 only infected cells express Mac-1 and that this percentage could be increased ~3 fold by co-expression with C/EBPa. In addition, most cells also expressed CD45 and some expressed F4/80 antigen. The PU.1 infected and the double infected cells, but not the C/EBPa only infected cells, also expressed a number of other myelomonocytic genes as detected by RT-PCR. These included CSF-1R (M-CSFR), GM-CSF Ralpha, Lysozyme, CD32, PYK2 as well as endogenous PU.1. The PU.1 induced reprogramming of fibroblasts required the DNA binding and transcription activation domains, but not the PEST domain of the transcription factor. To test whether the reprogrammed cells have functional macrophage properties, we generated two stable cell lines co-expressing C/EBPa and PU.1 delta PEST (wild type PU.1 is toxic in long-term cultures). These cells were morphologically altered, ingested carboxylated particles, and expressed functional Fc-gamma receptors but were unable to phagocytize antibody coated red blood cells. Remarkably, the two cells lines acquired CSF-1 dependence for growth. In accordance with this finding they exhibited a 10–15 fold reduction of CSF-1 production compared to NIH3T3 cells. The response observed was not restricted to fibroblast cell lines since both embryonic and adult fibroblasts could also be partially reprogrammed by co-infection with PU.1 and C/EBPa in that they expressed Mac-1, CD45, F4/80 and IA MHC antigens. In conclusion, enforced expression of PU.1 and C/EBPa converts fibroblasts into macrophage like cells, indicating that the combination of these two transcription factors is sufficient to regulate the majority of genes that define the myelomonocytic phenotype.

Identification of pituitary thyrotrope signature genes and regulatory elements

2020 ◽  
Author(s):  
Alexandre Z. Daly ◽  
Lindsey A. Dudley ◽  
Michael T. Peel ◽  
Stephen A. Liebhaber ◽  
Stephen C. J. Parker ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Cell Lines ◽  
Binding Sites ◽  
Critical Factor ◽  
Regulatory Elements ◽  
Thyroid Stimulating Hormone ◽  
Bzip Transcription Factor ◽  
Enhancer Element ◽  
Transcriptional Regulatory Elements

AbstractPituitary thyrotropes are specialized cells that produce thyroid stimulating hormone (TSH), a critical factor for growth and maintenance of metabolism. The transcription factors POU1F1 and GATA2 have been implicated in thyrotrope fate and transcriptional regulation of the beta subunit of TSH, Tshb, but no transcriptomic or epigenomic analyses of these cells has been undertaken. The goal of this work was to discover key transcriptional regulatory elements that drive thyrotrope fate. We identified the transcription factors and epigenomic changes in chromatin that are associated with differentiation of POU1F1-expressing progenitors into thyrotropes, a process modeled by two cell lines: one that represents an early, undifferentiated Pou1f1 lineage progenitor (GHF-T1) and one that is a committed thyrotrope that produces TSH (TαT1). We generated and compared RNA-seq, ATAC-seq, histone modification (including H3K27Ac, H3K4Me1, and H3K27Me3), and transcription factor (POU1F1) binding in these two cell lines to identify regulatory elements and candidate transcriptional regulators. We identified POU1F1 binding sites that were unique to each cell line. POU1F1 binding sites are commonly associated with bZIP transcription factor consensus binding sites in GHF-T1 cells and Helix-Turn-Helix (HTH) or basic Helix-Loop-Helix (bHLH) factors in TαT1 cells, suggesting that these classes of transcription factors may recruit or cooperate with POU1F1 binding to unique sites. We validated enhancer function of novel elements we mapped near Cga, Pitx1, Gata2, and Tshb by transfection in TαT1 cells. Finally, we confirmed that an enhancer element near Tshb can drive expression in thyrotropes of transgenic mice, and we demonstrate that GATA2 enhances Tshb expression through this element. These results extend the ENCODE multi-omic profiling approach to an organ that is critical for growth and metabolism, which should be valuable for understanding pituitary development and disease pathogenesis.

scholarly journals The AML-associated K313 mutation enhances C/EBPα activity by leading to C/EBPα overexpression

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Ian Edward Gentle ◽  
Isabel Moelter ◽  
Mohamed Tarek Badr ◽  
Konstanze Döhner ◽  
Michael Lübbert ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Culture ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Wild Type ◽  
Elevated Expression ◽  
Factor C ◽  
Acute Myeloid

AbstractMutations in the transcription factor C/EBPα are found in ~10% of all acute myeloid leukaemia (AML) cases but the contribution of these mutations to leukemogenesis is incompletely understood. We here use a mouse model of granulocyte progenitors expressing conditionally active HoxB8 to assess the cell biological and molecular activity of C/EBPα-mutations associated with human AML. Both N-terminal truncation and C-terminal AML-associated mutations of C/EBPα substantially altered differentiation of progenitors into mature neutrophils in cell culture. Closer analysis of the C/EBPα-K313-duplication showed expansion and prolonged survival of mutant C/EBPα-expressing granulocytes following adoptive transfer into mice. C/EBPα-protein containing the K313-mutation further showed strongly enhanced transcriptional activity compared with the wild-type protein at certain promoters. Analysis of differentially regulated genes in cells overexpressing C/EBPα-K313 indicates a strong correlation with genes regulated by C/EBPα. Analysis of transcription factor enrichment in the differentially regulated genes indicated a strong reliance of SPI1/PU.1, suggesting that despite reduced DNA binding, C/EBPα-K313 is active in regulating target gene expression and acts largely through a network of other transcription factors. Strikingly, the K313 mutation caused strongly elevated expression of C/EBPα-protein, which could also be seen in primary K313 mutated AML blasts, explaining the enhanced C/EBPα activity in K313-expressing cells.

scholarly journals Multi-omic profiling of pituitary thyrotropic cells and progenitors

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Alexandre Z. Daly ◽  
Lindsey A. Dudley ◽  
Michael T. Peel ◽  
Stephen A. Liebhaber ◽  
Stephen C. J. Parker ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Pituitary Gland ◽  
Cell Lines ◽  
Binding Sites ◽  
Critical Factor ◽  
Regulatory Elements ◽  
Thyroid Stimulating Hormone ◽  
Neuroendocrine Cells ◽  
Bzip Transcription Factor ◽  
Enhancer Element

Abstract Background The pituitary gland is a neuroendocrine organ containing diverse cell types specialized in secreting hormones that regulate physiology. Pituitary thyrotropes produce thyroid-stimulating hormone (TSH), a critical factor for growth and maintenance of metabolism. The transcription factors POU1F1 and GATA2 have been implicated in thyrotrope fate, but the transcriptomic and epigenomic landscapes of these neuroendocrine cells have not been characterized. The goal of this work was to discover transcriptional regulatory elements that drive thyrotrope fate. Results We identified the transcription factors and epigenomic changes in chromatin that are associated with differentiation of POU1F1-expressing progenitors into thyrotropes using cell lines that represent an undifferentiated Pou1f1 lineage progenitor (GHF-T1) and a committed thyrotrope line that produces TSH (TαT1). We compared RNA-seq, ATAC-seq, histone modification (H3K27Ac, H3K4Me1, and H3K27Me3), and POU1F1 binding in these cell lines. POU1F1 binding sites are commonly associated with bZIP transcription factor consensus binding sites in GHF-T1 cells and Helix-Turn-Helix (HTH) or basic Helix-Loop-Helix (bHLH) factors in TαT1 cells, suggesting that these classes of transcription factors may recruit or cooperate with POU1F1 binding at unique sites. We validated enhancer function of novel elements we mapped near Cga, Pitx1, Gata2, and Tshb by transfection in TαT1 cells. Finally, we confirmed that an enhancer element near Tshb can drive expression in thyrotropes of transgenic mice, and we demonstrate that GATA2 enhances Tshb expression through this element. Conclusion These results extend the ENCODE multi-omic profiling approach to the pituitary gland, which should be valuable for understanding pituitary development and disease pathogenesis. Graphical abstract

Specific transcription factors stimulate simian virus 40 and polyomavirus origins of DNA replication

1992 ◽  
Vol 12 (6) ◽  
pp. 2514-2524 ◽  
Author(s):  
Z S Guo ◽  
M L DePamphilis
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Dna Replication ◽  
Binding Sites ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Activation Domains ◽  
Auxiliary Component ◽  
Cell Extracts

The origins of DNA replication (ori) in simian virus 40 (SV40) and polyomavirus (Py) contain an auxiliary component (aux-2) composed of multiple transcription factor binding sites. To determine whether this component stimulated replication by binding specific transcription factors, aux-2 was replaced by synthetic oligonucleotides that bound a single transcription factor. Sp1 and T-antigen (T-ag) sites, which exist in the natural SV40 aux-2 sequence, provided approximately 75 and approximately 20%, respectively, of aux-2 activity when transfected into monkey cells. In cell extracts, only T-ag sites were active. AP1 binding sites could replace completely either SV40 or Py aux-2. Mutations that eliminated AP1 binding also eliminated AP1 stimulation of replication. Yeast GAL4 binding sites that strongly stimulated transcription in the presence of GAL4 proteins failed to stimulate SV40 DNA replication, although they did partially replace Py aux-2. Stimulation required the presence of proteins consisting of the GAL4 DNA binding domain fused to specific activation domains such as VP16 or c-Jun. These data demonstrate a clear role for transcription factors with specific activation domains in activating both SV40 and Py ori. However, no correlation was observed between the ability of specific proteins to stimulate promoter activity and their ability to stimulate origin activity. We propose that only transcription factors whose specific activation domains can interact with the T-ag initiation complex can stimulate SV40 and Py ori-core activity.

Epigenetic silencing of the immunoglobulin heavy-chain gene in classical Hodgkin lymphoma-derived cell lines contributes to the loss of immunoglobulin expression

Blood ◽  
2004 ◽  
Vol 104 (10) ◽  
pp. 3326-3334 ◽  
Author(s):  
Alexey Ushmorov ◽  
Olga Ritz ◽  
Michael Hummel ◽  
Frank Leithäuser ◽  
Peter Möller ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
B Cell ◽  
Hodgkin Lymphoma ◽  
Cell Lines ◽  
Epigenetic Silencing ◽  
Chain Gene ◽  
Classical Hodgkin Lymphoma ◽  
Regulatory Regions ◽  
The Impact

Abstract Immunoglobulin production is impaired in Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL) in spite of functional clonal rearrangements. The presence of “crippling” mutations in coding and regulatory regions, as well as down-regulation of B-cell-specific transcription factors, has been suggested as a potential reason for the lack of immunoglobulin (Ig) chain gene transcription. We have investigated the impact of epigenetic silencing in suppressing Ig heavy (H)-chain expression. Chromatin immunoprecipitation (ChIP) was used to analyze transcription factor binding to octamer motifs present in the IgH regulatory regions. Transcription factors were bound to these motifs in control cell lines, however, they were absent in the cHL-derived cell lines KMH2, L1236, and L428. Ectopic expression of octamer-binding transcription factor (Oct2) and/or B-cell Oct binding protein/Oct-binding factor (BOB.1/OBF.1) did not result in any measurable binding to these sites. Increased histone 3 Lysine 9 (H3-K9) methylation was observed in the promoter region of the IgH locus in L428 and L1236 cells. This is a typical feature of heterochromatic, transcriptionally silent regions. Treatment of cHL-derived cell lines with the DNA demethylating agent 5-aza-2′-deoxycytidine (5-aza-dC) partially reactivated IgH transcription and affected chromatin modifications. Our results suggest an important role of epigenetic silencing in the inhibition of IgH transcription in HRS cells. (Blood. 2004;104:3326-3334)

C-MYB and C/EBP Family Transcription Factors Regulate the Gfi-1 Promoter.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4214-4214
Author(s):  
Richard Dahl ◽  
Kristin S. Owens
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Chromatin Immunoprecipitation ◽  
Binding Sites ◽  
Myeloid Cells ◽  
Transient Transfection ◽  
Mobility Shift ◽  
Reporter Assays ◽  
Immature Myeloid Cells ◽  
Factor C

Abstract Gfi-1 −/− mice generate abnormal immature myeloid cells exhibiting characteristics of both monocytes and granulocytes. One of Gfi-1’s critical functions is to downregulate monocyte specific genes in order for granulocytes to develop properly. Since the transcription factors C/EBP alpha and C/EBP epsilon are needed for granulocyte development we hypothesized that these factors may regulate Gfi-1 expression. The Gfi-1 promoter contains several putative C/EBP binding sites and we show by electrophoretic mobility shift and chromatin immunoprecipitation that C/EBP family members can bind to some of these sites. However we were unable to see activation of the Gfi-1 promoter by C/EBP proteins in transient transfection reporter assays. Other groups have shown that C/EBP proteins can synergize with the transcription factor c-myb. We observed that the Gfi-1 promoter contains sites for the hematopoietic transcription factor c-myb. Sevral of these c-myb binding sites are adjacent to C/EBP binding sites. In reporter assays in non-hematopoietic cells c-myb activated the Gfi-1 promoter by itself and this activity was enhanced when we included either C/EBP alpha or epsilon in the transfection. Our data suggests that C/EBP proteins and c-myb regulate the transcription of Gfi-1 in myeloid cells.

Regulation of GM-CSF expression by the transcription factor c-Maf

2007 ◽  
Vol 120 (1) ◽  
pp. 56-63 ◽  
Author(s):  
Jane Gilmour ◽  
David J. Cousins ◽  
David F. Richards ◽  
Zahid Sattar ◽  
Tak H. Lee ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Gm Csf ◽  
Factor C

scholarly journals Reduced insulin/IGF1 signaling prevents immune aging via ZIP-10/bZIP–mediated feedforward loop

2021 ◽  
Vol 220 (5) ◽  
Author(s):  
Yujin Lee ◽  
Yoonji Jung ◽  
Dae-Eun Jeong ◽  
Wooseon Hwang ◽  
Seokjin Ham ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Mitogen Activated Protein Kinase ◽  
Bzip Transcription Factor ◽  
Immune Functions ◽  
C Elegans ◽  
Feedforward Loop ◽  
Mitogen Activated Protein ◽  
Living Organisms ◽  
Transcription Factor 1

A hallmark of aging is immunosenescence, a decline in immune functions, which appeared to be inevitable in living organisms, including Caenorhabditis elegans. Here, we show that genetic inhibition of the DAF-2/insulin/IGF-1 receptor drastically enhances immunocompetence in old age in C. elegans. We demonstrate that longevity-promoting DAF-16/FOXO and heat-shock transcription factor 1 (HSF-1) increase immunocompetence in old daf-2(−) animals. In contrast, p38 mitogen-activated protein kinase 1 (PMK-1), a key determinant of immunity, is only partially required for this rejuvenated immunity. The up-regulation of DAF-16/FOXO and HSF-1 decreases the expression of the zip-10/bZIP transcription factor, which in turn down-regulates INS-7, an agonistic insulin-like peptide, resulting in further reduction of insulin/IGF-1 signaling (IIS). Thus, reduced IIS prevents immune aging via the up-regulation of anti-aging transcription factors that modulate an endocrine insulin-like peptide through a feedforward mechanism. Because many functions of IIS are conserved across phyla, our study may lead to the development of strategies against immune aging in humans.

Crystal structure of the heterodimeric bZIP transcription factor c-Fos–c-Jun bound to DNA

Nature ◽  
1995 ◽  
Vol 373 (6511) ◽  
pp. 257-261 ◽  
Author(s):  
J. N. Mark Glover ◽  
Stephen C. Harrison
Keyword(s):  
Crystal Structure ◽  
Transcription Factor ◽  
Bzip Transcription Factor ◽  
Factor C
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