Stem Cells and Tissue Renewal
Bruce Alberts, Alexander Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter in Molecular Biology of the Cell, 2017
This chapter illustrates some of the diversity of specialized cell types and observes how they work together to perform their tasks. It examines in particular the role played in many tissues by stem cells —cells that are specialized to provide a fresh supply of differentiated cells where these need to be continually replaced or regenerated. The chapter discusses how stem cells is generated and manipulated artificially, and confronts the practical question that underlies the current storm of interest in stem-cell technology. It explains how one can understand the processes of cell differentiation and tissue renewal to improve upon nature, and make good those injuries and failings of the human body that have hitherto seemed to be beyond repair. Many tissues in the adult mammalian body are continually renewed by stem cells. The lining of the gut renews itself more rapidly than any other tissue in the mammalian body and provides a paradigm for the workings of stem-cell systems.
Control of Cell Type-Specific Gene Expression
David S. Latchman in Gene Control, 2020
The transcription factor NFκB regulates the B-cell-specific expression of the immunoglobulin κ light-chain gene. Immunoglobulin κ gene expression is activated when pre-B cells differentiate into mature B lymphocytes which produce immunoglobulin. The activation of a specific transcription factor, such as NFκB, from a preexisting inactive form can play a role in cell type-specific gene expression as well as in the activation of gene expression in response to specific cellular signals. MyoD represents a transcription factor that is controlled at the level of its synthesis, with such regulation playing a key role in muscle cell differentiation. A similar conversion of MEF2 to a transcriptional repressor is observed when the protein is modified by addition of the small protein small ubiquitin-related modifier, whereas acetylation of MEF2 promotes its ability to act as a transcriptional activator. The MEF2 genes contain a specific exon known as β, which encodes an additional transcriptional activation domain.
Aspects of early mammalian development, cell differentiation, and stem cells
Tom Strachan, Andrew P Read in Human Molecular Genetics, 2018
In this chapter, the authors consider how the mammalian zygote gives rise to early lineages of more specialized cells, charting the initial steps of tissue differentiation and the formation of the three primary germ layers and germ cells against a background of mammalian embryonic development. They introduce various aspects of stem cells and cell differentiation. Most attention has focused on models that deal with post-compaction breaking of symmetry: either the symmetry of cells (cell polarity), or of their positions in the embryo (cell surface location versus interior location), or both. Tissue-specific stem cells are maintained in special supportive microenvironments, called stem cell niches, where chemical signals are conveyed from neighboring cells and extracellular matrix to receptors on the stem cell to support stem cell activity and renewal. Human blood cells are initially made in certain embryonic structures before the fetal liver takes over production.
Effect of rhTGF-β1 combined with bone grafts on human periodontal cell differentiation
Published in Growth Factors, 2011
C. E. Markopoulou, X. E. Dereka, H. N. Vavouraki, E. E. Pepelassi, A. A. Mamalis, I. K. Karoussis, I. A. Vrotsos
Various techniques and materials have been proposed for the treatment of periodontal defects. In periodontal regeneration, periodontal ligament (PDL) cell differentiation as well as certain growth factors and their delivery system applied are critical. The purpose of this study was to evaluate the in vitro effect of recombinant human transforming growth factor-beta 1 (rhTGF-β1) combined with two different bone grafts on human PDL (hPDL) cell differentiation. The hPDL cells were treated with TGF-β1 alone or in combination with a calcified freeze-dried bone allograft (FDBA) and a porous biphasic calcium phosphate (BC) bone graft. Cell differentiation effect was estimated by measuring alkaline phosphatase (ALPase) activity and osteocalcin secretion. Results demonstrated that rhTGF-β1 alone or in combination with FDBA and BC provoked a significant (p < 0.05) increase in ALPase activity as compared with controls. The findings of this study confirmed the beneficial role of rhTGF-β1 combined with FDBA and BC as carriers in periodontal regeneration.
Vibsanol A induces differentiation of acute myeloid leukemia cells via activation of the PKC signaling pathway and induction of ROS
Published in Leukemia & Lymphoma, 2018
Meng Yang, Shuang Xing, Hong-Ling Ou, Lu Zhang, Xing Shen, Guo-Lin Xiong, Fang-Min Wang, He Xiao, Yan-Hong Tu, Yu-Wen Cong, Xin-Ru Wang, Zu-Yin Yu
Identifying novel differentiating agents to promote leukemia-cell differentiation is a pressing need. Here, we demonstrated that vibsanol A, a vibsane-type diterpenoid, inhibited the growth of acute myeloid leukemia (AML) cells via induction of cell differentiation, which was characterized by G1 cell cycle arrest. The differentiation-inducing effects of vibsanol A were dependent upon protein kinase C (PKC) activation, and subsequent activation of the extracellular signal-regulated kinase (ERK) pathway. Furthermore, vibsanol A treatment increased reactive oxygen species (ROS) levels, and the ROS scavenger NAC reversed the vibsanol A-induced cell differentiation, indicating an important role for ROS in the action of vibsanol A. Finally, vibsanol A exhibited a differentiation-enhancing effect when used in combination with all-trans retinoic acid in AML cells. Overall results suggested that vibsanol A induces AML cell differentiation via activation of the PKC/ERK signaling and induction of ROS. Vibsanol A may prove to be an effective differentiating agent against AML.
Adipogenesis: a cross-talk between cell proliferation and cell differentiation
Published in Annals of Medicine, 2003
The transition between cell proliferation and cell differentiation taking place during adipocyte differentiation is a tightly regulated process where both cell cycle regulators and differentiating factors interact, creating a cascade of events leading to the commitment of the cells into the adipocyte phenotype. Based on in-vitro cell models of adipocyte differentiation, the different stages of adipogenesis have been established, each of them with a particular pattern of gene expression. Re-entry into the cell cycle of growth-arrested preadipocytes is known as the clonal expansion phase. Growth-arrested preadipocytes undergo several rounds of cell cycle before terminally differentiating into adipocytes, suggesting that a cross-talk might exist between the cell cycle or the cell proliferation machinery and the factors controlling cell differentiation. I will focus this review on the influence of the proliferative phase of preadipocytes in the adipocyte differentiation process.