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| 2. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
- 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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| 9. |
- 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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