| 1. |
- Funa, Nina, et al.
(författare)
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Interdependent fibroblast growth factor and activin A signaling promotes the expression of endodermal genes in differentiating mouse embryonic stem cells expressing Src Homology 2-domain inactive Shb
- 2008
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Ingår i: Differentiation. - : Elsevier BV. - 0301-4681 .- 1432-0436. ; 76:5, s. 443-453
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms controlling endodermal development during stem cell differentiation have been only partly elucidated, although previous studies have suggested the participation of fibroblast growth factor (FGF) and activin A in these processes. Shb is a Src homology 2 (SH2) domain-containing adapter protein that has been implicated in FGF receptor 1 (FGFR1) signaling. To study the putative crosstalk between activin A and Shb-dependent FGF signaling in the differentiation of endoderm from embryonic stem (ES) cells, embryoid bodies (EBs) derived from mouse ES cells overexpressing wild-type Shb or Shb with a mutated SH2 domain (R522K-Shb) were cultured in the presence of activin A. We show that expression of R522K-Shb results in up-regulation of FGFR1 and FGF2 in EBs. Addition of activin A to the cultures enhances the expression of endodermal genes primarily in EBs expressing mutant Shb. Inhibition of FGF signaling by the addition of the FGFR1 inhibitor SU5402 completely counteracts the synergistic effects of R522K-Shb and activin A. In conclusion, the present results suggest that expression of R522K-Shb enhances certain signaling pathways downstream of FGF and that an interplay between FGF and activin A participates in ES cell differentiation to endoderm.
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| 2. |
- Roberg, Karin, 1957-, et al.
(författare)
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Multiple genotypic aberrances associate to terminal differentiation-deficiency of an oral squamous cell carcinoma in serum-free culture
- 2008
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Ingår i: Differentiation. - : Elsevier BV. - 0301-4681 .- 1432-0436. ; 76:8, s. 868-880
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Tidskriftsartikel (refereegranskat)abstract
- Oral squamous cell carcinoma (OSCC) lines proliferative in the serum-free conditions devised for normal oral keratinocytes (NOK) are virtually absent, complicating studies of carcinogenesis. A tongue squamous cell carcinoma generated under conditions for normal cell culture an apparently immortal line (termed LK0412) that has undergone ≥200 population doublings from over a year in culture. LK0412 exhibited epithelial morphology, intermediate filaments, desmosomes, and cytokeratin. Soft agar growth and tumorigenicity in athymic nude mice indicated the malignant phenotype. Compared with NOK, LK0412 exhibited increased indices for proliferation and apoptosis, and a decreased terminal differentiation index. Fetal bovine serum inhibited growth and increased apoptosis but failed to induce terminal differentiation of LK0412; the latter outcome differed clearly from that in NOK. Gene ontology assessment of transcript profiles implicated multiple alterations in biological processes, molecular functions, and cellular components in LK0412. Genetic changes, some that were confirmed to the protein level, included previously proposed OSCC markers, i.e., BAX, CDC2, and TP53, as well as multiple cancer-associated genes not considered for OSCC, e.g., BST2, CRIP1, ISG15, KLRC1, NEDD9, NNMT, and TWIST1. Elevation of p53 protein agreed with a missense mutation detectable in both the LK0412 line and the original tumor specimen. Moderate differentiation characterized the original tumor as well as tumors generated from inoculation of LK0412 in mice. Overall, the results suggest that the LK0412 cell line represent a subgroup of OSCC with unique genomic and phenotypic profiles. LK0412 should be useful to exploration of OSCC development, particularly the deregulated growth and differentiation responsiveness to serum factors.
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| 3. |
- Singh, Umashankar, et al.
(författare)
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Carboxypeptidase E in the mouse placenta
- 2006
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Ingår i: Differentiation. - : Elsevier BV. - 0301-4681 .- 1432-0436. ; 74:9-10, s. 648-660
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Tidskriftsartikel (refereegranskat)abstract
- Carboxypeptidase E (CPE) has important functions in processing of endocrine pro-peptides, such as pro-insulin, pro-opiomelanocortin, or pro-gonadotropin-releasing hormone, as evidenced by the hyperpro-insulinemia, obesity, and sterility of Cpe mutant mice. Down-regulation of Cpe in enlarged placentas of interspecific hybrid (interspecies hybrid placental dysplasia (IHPD)) and cloned mice suggested that reduced CPE enzyme and receptor activity could underlie abnormal placental phenotypes. In this study, we have explored the role of Cpe in murine placentation by determining its expression at various stages of gestation, and by phenotypic analysis of Cpe mutant placentas. Our results show that Cpe and Carboxypeptidase D (Cpd), another carboxypeptidase with a very similar function, are strictly co-localized in the mouse placenta from late mid-gestation to term. We also show that absence of CPE causes a sporadic but striking placental phenotype characterized by an increase in giant and glycogen cell numbers and giant cell hypertrophy. Microarray-based transcriptional pro. ling of Cpe mutant placentas identified only a very small number of genes with altered expression, including Dtprp, which belongs to the prolactin gene family. Concordant deregulation of Cpe and Cpd in abnormal placentas of interspecies hybrids before the onset of IHPD phenotype and recapitulation of some phenotypes of IHPD hyperplastic placentas in Cpe mutant placentas suggests that these two genes are causally involved in IHPD and may function as speciation genes in the genus Mus.
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| 4. |
- Zhang, Xiao-Qun, et al.
(författare)
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Gli1 is not required for Pdgfralpha expression during mouse embryonic development
- 2005
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Ingår i: Differentiation. - : Elsevier BV. - 0301-4681 .- 1432-0436. ; 73:2-3, s. 109-19
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Tidskriftsartikel (refereegranskat)abstract
- Pdgfra is expressed in the mesenchyme of multiple organs during embryonic development and Pdgfrα is involved in cell proliferation, differentiation, migration, and apoptosis in many tissues. A fine-tuned regulation of gene transcription is required to achieve these effects. To investigate if the Shh signaling pathway is involved in the tightly regulated Pdgfra expression during embryogenesis, we systematically compared Gli1 and Pdgfrα mRNA expression patterns in vivo from mouse embryonic day 9.5 to 14.5. We found that an initial partly overlapping expression of Gli1 and Pdgfrα in the mesenchyme of foregut and somites was changed to different expression patterns when the mesenchyme differentiated into specialized structures such as intestinal villi and chondrocytes. Gli1 and Pdgfra were also expressed differently in the developing lung, heart, central nervous system, skin, tooth, and eye. Importantly, neither Pdgfrα mRNA patterns nor levels were altered in Ihh mutant embryos although Gli1 and Ptc mRNA levels were dramatically reduced. Our results demonstrate that Gli1 is not required to induce Pdgfra expression during embryonic bone development, and are consistent with previous findings that Pdgfrα and Hh pathways serve different functions in, e.g., bone, gut, and lung development. However, we cannot exclude the possibility that Glis can have more complex regulatory effects on Pdgfra gene activity, nor can we exclude such effects in pathological conditions.
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| 5. |
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| 6. |
- Boije, Henrik, et al.
(författare)
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Forkheadbox N4 (FoxN4) triggers context-dependent differentiation in the developing chick retina and neural tube
- 2013
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Ingår i: Differentiation. - : Elsevier BV. - 0301-4681 .- 1432-0436. ; 85:1-2, s. 11-19
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Tidskriftsartikel (refereegranskat)abstract
- FoxN4, a forkhead box transcription factor, is expressed in the chicken eye field and in retinal progenitor cells (RPCs) throughout development. FoxN4 labelling overlapped with that of Pax6 and Sox2, two crucial transcription factors for RPCs. Later, during neurogenesis in the retina, some cells were intensely and transiently labelled for FoxN4. These cells co-labelled for Lim1, a transcription factor expressed in early-born horizontal cells. The result suggests that high levels of FoxN4 combined with expression of Lim1 define a population of RPCs committed to the horizontal cell fate prior to their last apical mitosis. As these prospective horizontal cells develop, their FoxN4 expression is down-regulated. Previous results suggested that FoxN4 is important for the generation of horizontal and amacrine cells but that it is not sufficient for the generation of horizontal cells (Li et al., 2004). We found that over-expression of FoxN4 in embryonic day 3 chicken retina could activate horizontal cell markers Prox1 and Lim1, and that it generated numerous and ectopically located horizontal cells of both main subtypes. However, genes expressed in photoreceptors, amacrine and ganglion cells were also activated, indicating that FoxN4 triggered the expression of several differentiation factors. This effect was not exclusive for the retina but was also seen when FoxN4 was over-expressed in the mesencephalic neural tube. Combining the results from over-expression and wild-type expression data we suggest a model where a low level of FoxN4 is maintained in RPCs and that increased levels during a restricted period trigger neurogenesis and commitment of RPCs to the horizontal cell fate.
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| 7. |
- El-Serafi, Ahmed Taher, 1977-, et al.
(författare)
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Epigenetic modifiers influence lineage commitment of human bone marrow stromal cells: Differential effects of 5-aza-deoxycytidine and trichostatin A
- 2011
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Ingår i: Differentiation. - London, United Kingdom : Elsevier. - 0301-4681 .- 1432-0436. ; 81:1, s. 35-41
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Tidskriftsartikel (refereegranskat)abstract
- Clinical imperatives for new bone to replace or restore the function of traumatized or bone lost as a consequence of age or disease has led to the need for therapies or procedures to generate bone for skeletal applications. However, current in vitro methods for the differentiation of human bone marrow stromal cells (HBMSCs) do not, to date, produce homogeneous cell populations of the osteogenic or chondrogenic lineages. As epigenetic modifiers are known to influence differentiation, we investigated the effects of the DNA demethylating agent 5-aza-2′-deoxycytidine (5-aza-dC) or the histone deacetylase inhibitor trichostatin A (TSA) on osteogenic and chondrogenic differentiation. Monolayer cultures of HBMSCs were treated for 3 days with the 5-aza-dC or TSA, followed by culture in the absence of modifiers. Cells were subsequently grown in pellet culture to determine matrix production. 5-aza-dC stimulated osteogenic differentiation as evidenced by enhanced alkaline phosphatase activity, increased Runx-2 expression in monolayer, and increased osteoid formation in 3D cell pellets. In pellets cultured in chondrogenic media, TSA enhanced cartilage matrix formation and chondrogenic structure. These findings indicate the potential of epigenetic modifiers, as agents, possibly in combination with other factors, to enhance the ability of HBMSCs to form functional bone or cartilage with significant therapeutic implications therein.
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| 8. |
- El-Serafi, Ahmed T., et al.
(författare)
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Paradoxical effects of the epigenetic modifiers 5-aza-deoxycytidine and suberoylanilide hydroxamic acid on adipogenesis
- 2019
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Ingår i: Differentiation. - : Elsevier. - 0301-4681 .- 1432-0436. ; 106, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Adipogenesis is an important biological process that is linked to obesity and metabolic disorders. On the other hand, fat regeneration is crucial as a restorative approach following mastectomy or severe burn injury. Furthermore, optimizing an in-vitro model of adipogenesis, which would help in understanding the possible effects and/or side effects of fat-soluble drugs and anti-obesity remedies, in addition to the developmental studies. Epigenetic is an important factor that is involved in cellular differentiation and commitment. This study aimed at investigating the effect of DNA methylation and histone deactylases inhibitors, 5-Aza-deoxycytidine (5Aza-dC) and Suberoylanilide hydroxamic acid (SAHA), on the adipogenic differentiation process. The two modifiers were applied according to our previously published protocol, followed by three cycles of a classical, two-step adipogenesis protocol. The cells pretreated with SAHA showed enhanced expression of the many adipogenic genes, including peroxisome proliferator-activated receptor-gamma as well as the accumulation of intracytoplasmic fat as shown by oil red and Nile red staining and the secretion of adipokines, such as MCP-1 and IP-10. On contrary, 5-Aza-dC inhibited all these markers. In conclusion, adding the reported step with SAHA to the differentiation protocols could have an impact on the progress of the in-vitro fat regenerative approach. The possible role of 5-Aza-dC in the inhibition of adipogenesis can be of clinical interest and will need further characterization in the future.
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| 9. |
- El-Serafi, Ahmed T., et al.
(författare)
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Skin regeneration in three dimensions, current status, challenges and opportunities
- 2017
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Ingår i: Differentiation. - : Elsevier. - 0301-4681 .- 1432-0436. ; 96, s. 26-29
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Forskningsöversikt (refereegranskat)abstract
- Skin regeneration is a life-saving need for many patients, whom list is stretched from burn victims to motor-car accidents. Spraying cells, either keratinocytes or stem cells, were associated with variable results and, in many cases, unfavorable outcomes. As the spatial configuration of the skin is distinctive, many trials investigated the bio-printing or the construction of three dimensional skin models where different layers of the skin were preserved. Although some of these models showed the histological configuration of the skin, their acceptance by the wound was questionable as a consequence of delayed vascularization. In this mini-review, different models for three dimensional regeneration of the skin will be discussed with their main points of strength and challenges as well as their possible opportunities.
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| 10. |
- Junker, Johan, et al.
(författare)
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Differentiation of human dermal fibroblasts towards endothelial cells
- 2013
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Ingår i: Differentiation. - Oxon, United Kingdom : Elsevier. - 0301-4681 .- 1432-0436. ; 85:3, s. 67-77
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Tidskriftsartikel (refereegranskat)abstract
- The ultimate goal of vascular tissue engineering is the production of functional grafts for clinical use. Difficulties acquiring autologous endothelial cells have motivated the search for alternative cell sources. Differentiation of dermal fibroblasts towards several mesenchymal lineages as well as endothelial cells has been proposed. The aim of the present study was to investigate the endothelial differentiation capacity of human dermal fibroblasts on a gene expression, protein expression and functional physiological level. Endothelial differentiation of fibroblasts was induced by culturing cells in 30% human serum, but not in fetal calf serum. Expression of proteins and genes relevant for endothelial function and differentiation was increased after induction. Furthermore, fibroblasts exposed to 30% human serum displayed increased uptake of low-density lipoprotein and formation of capillary-like networks. The results of this study may have an impact on cell sourcing for vascular tissue engineering, and the development of methods for vascularization of autologous tissue engineered constructs.
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