scholarly journals Preparation of TGF-beta1/affinity-bound alginate macroporous scaffolds

2018 ◽  
Vol 72 (2) ◽  
pp. 81-90
Author(s):  
Tali Re'em
Keyword(s):  
Binding Sites ◽  
Chondrogenic Differentiation ◽  
Preparation Method ◽  
Human Mesenchymal Stem Cells ◽  
Release Profile ◽  
Inductive System ◽  
Efficient Induction ◽  
Spatio Temporal ◽  
Profile Study ◽  
Alginate Scaffold

Spatio-temporal presentation of growth factors is one of the key attributes of the cell's microenvironment. The design of macroporous alginate scaffolds, wherein TGF-b1 or BMP-4 is electrostatically bound to affinity binding sites of alginate sulfate, mimicking their presentation by the extracellular matrix (ECM), was previously shown to enable sustained presentation and release of each factor, thus increasing their biological activity. Specifically, TGF-b1/affinity-bound scaffolds induced the chondrogenic differentiation of human mesenchymal stem cells (hMSCs) seeded within these scaffolds. The prolonged activity of the affinity-bound TGF-b1 enabled efficient induction of signaling pathways leading to chondrogenesis, up to the appearance of committed chondrocytes. Similarly, BMP-4 affinity-bound to the macroporous alginate scaffold enabled efficient induction of osteogenic differentiation in hMSC constructs. Subsequent construction of a multicompartment inductive system, spatially-presenting TGF-b1 and BMP-4 in two distinct layers, enabled complete differentiation of hMSC to chondrocytes and osteoblasts, depending on the type of factor in use in the respective layer. This paper describes in detail the preparation method of the TGF-b1 or BMP4/affinity-bound alginate scaffolds, and the set of analyses performed to characterize the resultant scaffolds, including release profile study, released factor bioactivity, and functionality of the scaffolds as hMSC-inductive scaffolds.

Biomimetic hydrogels for chondrogenic differentiation of human mesenchymal stem cells to neocartilage

Biomaterials ◽  
2010 ◽  
Vol 31 (28) ◽  
pp. 7298-7307 ◽  
Author(s):  
Shao Qiong Liu ◽  
Quan Tian ◽  
James L. Hedrick ◽  
James Hoi Po Hui ◽  
Pui Lai Rachel Ee ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Chondrogenic Differentiation ◽  
Human Mesenchymal Stem Cells

Global regulation of mitochondrial biogenesis in Saccharomyces cerevisiae: ABF1 and CPF1 play opposite roles in regulating expression of the QCR8 gene, which encodes subunit VIII of the mitochondrial ubiquinol-cytochrome c oxidoreductase

1992 ◽  
Vol 12 (6) ◽  
pp. 2872-2883
Author(s):  
J H de Winde ◽  
L A Grivell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cytochrome C ◽  
Mitochondrial Biogenesis ◽  
Binding Sites ◽  
Promoter Region ◽  
S Phase ◽  
Negative Regulator ◽  
Global Regulation ◽  
Two Factors ◽  
Efficient Induction

The multifunctional DNA-binding proteins ABF1 and CPF1 bind in a mutually exclusive manner to the promoter region of the QCR8 gene, which encodes 11-kDa subunit VIII of the Saccharomyces cerevisiae mitochondrial ubiquinol-cytochrome c oxidoreductase (QCR). We investigated the roles that the two factors play in transcriptional regulation of this gene. To this end, the overlapping binding sites for ABF1 and CPF1 were mutated and placed in the chromosomal context of the QCR8 promoter. The effects on transcription of the QCR8 gene were analyzed both under steady-state conditions and during nutritional shifts. We found that ABF1 is required for repressed and derepressed transcription levels and for efficient induction of transcription upon escape from catabolite repression, independently of DNA replication. CPF1 acts as a negative regulator, modulating the overall induction response. Alleviation of repression through CPF1 requires passage through the S phase. Implications of these findings for the roles played by ABF1 and CPF1 in global regulation of mitochondrial biogenesis are discussed.

scholarly journals Genome-wide effects of chromatin on vitamin D signaling

2020 ◽  
Vol 64 (4) ◽  
pp. R45-R56 ◽  
Author(s):  
Andrea Hanel ◽  
Henna-Riikka Malmberg ◽  
Carsten Carlberg
Keyword(s):  
Vitamin D ◽  
Binding Sites ◽  
Target Genes ◽  
Chromatin Accessibility ◽  
Transcription Start Sites ◽  
Dihydroxyvitamin D ◽  
Genome Wide ◽  
Spatio Temporal ◽  
Vitamin D Signaling ◽  
The Impact

Molecular endocrinology of vitamin D is based on the activation of the transcription factor vitamin D receptor (VDR) by the vitamin D metabolite 1α,25-dihydroxyvitamin D3. This nuclear vitamin D-sensing process causes epigenome-wide effects, such as changes in chromatin accessibility as well as in the contact of VDR and its supporting pioneer factors with thousands of genomic binding sites, referred to as vitamin D response elements. VDR binding enhancer regions loop to transcription start sites of hundreds of vitamin D target genes resulting in changes of their expression. Thus, vitamin D signaling is based on epigenome- and transcriptome-wide shifts in VDR-expressing tissues. Monocytes are the most responsive cell type of the immune system and serve as a paradigm for uncovering the chromatin model of vitamin D signaling. In this review, an alternative approach for selecting vitamin D target genes is presented, which are most relevant for understanding the impact of vitamin D endocrinology on innate immunity. Different scenarios of the regulation of primary upregulated vitamin D target genes are presented, in which vitamin D-driven super-enhancers comprise a cluster of persistent (constant) and/or inducible (transient) VDR-binding sites. In conclusion, the spatio-temporal VDR binding in the context of chromatin is most critical for the regulation of vitamin D target genes.

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