Introduction
Ugo Ripamonti in The Geometric Induction of Bone Formation, 2020
Extensive research work has led to our deep understanding of the role of biomaterial surfaces in controlling the induction of cell differentiation. The geometric guided tissue induction does result in specific genetic and morphogenetic pathways initiating in the induction of selected morphogenetic processes including the induction of bone formation as well as the geometric control of capillary architecture. Mechanical regulation on micropillars also affects subcellular nuclear geometry which further regulates stem cell differentiation. Geometry, geometric configurations, nanotopographic surface alterations and modifications, sintered surface microstructures, pits, micro-concavities and concavities are all geometric cues that define geometric configurations endowed with the striking capacity to induce cellular differentiation and tissue induction. Demineralized incisors harvested and prepared from adult rats were transplanted in symmetrical subcutaneous contralateral sites of allogeneic animals. Harvested specimens showed the induction of chondrogenesis in the apical part of the pulp chamber by day 7 after transplantation.
The Mechanisms Behind Tumour Repopulation
Loredana G. Marcu, Iuliana Toma-Dasu, Alexandru Dasu, Claes Mercke in Radiotherapy and Clinical Radiobiology of Head and Neck Cancer, 2018
Cancer cells with stem-like properties represent a subpopulation of tumour cells that are able to proliferate indefinitely, can create all lineages of the original tumour, are more quiescent than non-CSCs, and can regenerate through both symmetric and asymmetric division. Radiotherapy causes cell killing, which allows the surviving tumour clonogens the opportunity to multiply with a reduced cell-loss factor and possibly shorter cell cycle. This behaviour was shown to be characteristic to squamous cell carcinomas and was labelled accelerated repopulation. The Cancer stem cells (CSC) model stipulates that malignant tumours are organised hierarchically and their growth is driven by a small subgroup of CSCs that can also undergo epigenetic transformation, the equivalent of cellular differentiation of normal cells. Two of the main properties of stem cells are: self-renewal, by creating identical copies of themselves and lineage-specific differentiation, by creating non-stem, differentiated progenies. Cancer stem cells were shown to exhibit higher resistance to treatment than non-stem cancer cells.
Epigenetic Control of Cellular Differentiation
Lyle Armstrong in Epigenetics, 2020
Different types of cells arise early in embryonic development, and epigenetic control of gene expression is used to establish specific gene expression patterns that distinguish individual types of cells. The early embryos of most multicellular eukaryotes begin as groups of cells that are termed totipotent because each cell seems to have an equal ability to become any of the cell types generated as the embryo develops. This chapter introduces the basic concepts behind the cellular differentiation that permits development of the embryo. With the exception of erythrocytes and post-meiotic gametes, most of the cells of the developing organism contain an identical copy of the original genome that was generated by the combination of the two parental genomes shortly after fertilization. The basis of cell differentiation is that specific patterns of gene expression apply to different types of cells, but the fact that they all probably possess the same genome implies that epigenetic regulation must control the cell-type-specific expression pattern.
SETD6 monomethylates H2AZ on lysine 7 and is required for the maintenance of embryonic stem cell self-renewal
Published in Epigenetics, 2013
Olivier Binda, Ana Sevilla, Gary LeRoy, Ihor R. Lemischka, Benjamin A. Garcia, Stéphane Richard
The histone H2A variant H2AZ is an essential chromatin signaling factor. Herein, we report that H2AZ is monomethylated at lysine 7 (H2AZK7me1) by the lysine methyltransferase SETD6. We observed that methylation of H2AZ increased noticeably upon cellular differentiation of mouse embryonic stem cells (mESCs). H2AZK7me1 and the repressive H3K27me3 mark were found near the transcriptional start sites of differentiation marker genes, but were removed upon retinoic acid-induced cellular differentiation. The depletion of Setd6 in mESCs led to cellular differentiation, compromised self-renewal, and poor clonogenicity. These findings demonstrate that mESCs require Setd6 for self-renewal and portray H2AZK7me1 as a marker of cellular differentiation.
Local chromatin dynamics of transcription factors imply cell-lineage specific functions during cellular differentiation
Published in Epigenetics, 2012
Rui Tian, Jianxing Feng, Xiaopeng Cai, Yong Zhang
Chromatin dynamics across cellular differentiation states is an emerging perspective from which the mechanism of global gene expression regulation may be better understood. While the roles of some histone marks have been partially interpreted in terms of their association with gene transcription, the dynamics of histone marks from a loci-specific perspective during cellular differentiation is not well studied. We established a method to systematically assess the histone modification variations of genes across various cellular differentiation states. We calculated the histone modification variation scores of H3K4me3, H3K27me3 and H3K36me3 for over 1300 curated transcription factors (TFs) during human blood cell differentiation. Hematopoietic-specific TFs (identified by literature mining) were significantly overrepresented by TFs with higher histone modification variation scores. Hierarchical clustering of all TFs based on the histone modification variation scores defined a group of TFs where known or potential hematopoietic-specific TFs were remarkably enriched. Our results suggest that local chromatin state dynamics of transcription factors across cellular differentiation states could imply cell lineage-specific functions. More importantly, our method can be applied to broader systems, holding the promise to discover de novo, lineage-specific TFs by interrogating their histone modification dynamics across cell lineages.
Biological implications of estrogen and androgen effects on androgen receptor and its mRNA levels in human uterine endometrium
Published in Gynecological Endocrinology, 1995
J. Fujimoto, M. Nishigaki, M. Hori, S. Ichigo, T. Itoh, T. Tamaya
It has been shown that some effects of testosterone are different from those of its 5α-reduced metabolite, dihydrotestosterone. Briefly, activities of testosterone might be related to cellular differentiation, whereas dihydrotestosterone acts on cellular proliferation. The number of testosterone binding sites in the uterine endometrium was increased by estradiol dipropionate, and this increase was down-regulated by testosterone cypionate. Dihydrotestosterone-specific binding sites in the endometrium were not modulated by estradiol dipropionate and testosterone cypionate. The dissociation constants of the bindings sites for testosterone and dihydrotestosterone were not altered by these steroids. Estradiol dipropionate with or without testosterone cypionate induced androgen receptor mRNA expression in the endometrium. In conclusion, testosterone might predominantly affect cellular differentiation in the endometrium.
Related Knowledge Centers
- Cell Division
- Membrane Potential
- Tissue
- Zygote
- Cell Type
- Cell
- Developmental Biology