Satellite cells and exercise
Adam P. Sharples, James P. Morton, Henning Wackerhage in Molecular Exercise Physiology, 2022
How do dividing satellite cells decide whether to progress to differentiation or to self-renew? This is an area of active research, but it is known that the decision relies upon asymmetric cell division, which is the process by which two daughter cells adopt differing cellular fates. A group of proteins known as the Par complex are well established regulators of asymmetric cell division (27). In a satellite cell undergoing cell division (mitosis), the Par complex is localised to one side of the cell and activates p38 Mitogen-Activated Protein Kinase (p38 MAPK) signalling (28). MAPK signalling induces cell proliferation (29, 30) and turns on MyoD within the cell, such that one daughter cell becomes a bona fide myoblast, whilst the satellite cell without active p38 MAPK and MyoD returns to quiescence.
Stem cell biology
Christine Hauskeller, Arne Manzeschke, Anja Pichl in The Matrix of Stem Cell Research, 2019
Alongside their experimental relativity, stem cell concepts and hypotheses involve substantive assumptions about biological development. At the cellular level, these assumptions can be made more explicit by further analysing variable D: a developmental process that orders cell states with respect to differentiation. Lineages are modelled using ‘tree diagrams’ that track relations between generations of reproducing entities.17 Variable D can be conceptualized as a space of possible lineage tree models. Each model within this space has a particular number and arrangement of developmental stages, branch-points, and termini (see above). The number of stages distinguished is the ‘depth’ of the cell hierarchy for a particular lineage. The simplest cases, like asymmetric cell division, distinguish only two stages: a stem and a more differentiated state (Figure 8.2). Other developmental processes are more elaborate. The number of branch-points indicates the range of different pathways within a cell lineage. The number of termini of these pathways is a measure of the initiating stem cell’s developmental potential.
Therapeutic Targeting of the Melanoma Stem Cell Population
Sanjiv S. Agarwala, Vernon K. Sondak in Melanoma, 2008
Tumors typically arise in tissues with rapid cell turnover, such as the gastrointestinal tract, the hematopoietic system, and the skin. In these organs, there is a continuous ordered cycle of cell proliferation that replaces the short-lived differentiated cells. This cell proliferation is a highly controlled process whereby a small pool of self-renewing stem cells gives rise to a population of proliferating progenitor cells that undergo limited rounds of cell division before reaching a state of terminal differentiation. In this system, only the stem cells are long-lived, and they have the unique property of being able to undergo self-renewing cell division where at least one of the progeny “daughter cells” remains as a stem cell—a process termed “asymmetric cell division.” The daughter cells then either remain as stem cells or undergo a further process of differentiation to become either a multipotent progenitor or a transient amplifying cell. It is through the generation of many transient amplifying cells that stem cells can generate large cell numbers to repopulate entire tissues (Fig. 2). As transient amplifying cells undergo multiple rounds of cell division, their progeny become progressively more differentiated and start losing their potential for further cell proliferation. This delicate balance between self-renewal and differentiation is critical in retaining the size of stem cell pool. Stem cells exist within a specialized microenvironment termed “the stem cell niche.” The niche plays a critical role in maintaining the undifferentiated state of the stem cell pool through the provision of paracrine and extracellular matrix signals.
TRIM3 Inhibits H2O2-Induced Apoptosis in Human Lens Epithelial Cells by Decreasing p53 via Ubiquitination
Published in Current Eye Research, 2022
Yingying Deng, Yuhua Shi, Chenting Wen
TRIM3, an E3 ligase from the TRIM family, has an anti-oncogenic role in many cancers. In glioblastoma, it can restore asymmetric cell division.18 In liver cancer, it can inhibit cancer cell proliferation, migration, and invasion.13 In cervical cancer, it can promote cancer cell apoptosis and inhibit cancer cell proliferation.14 However, to our knowledge, no study has explored the role of TRIM3 in cataracts. Here, we first reported that TRIM3 inhibited the H2O2-induced HLEC apoptosis, suggesting the possible involvement of TRIM3 in cataracts. Further studies are needed to deeply understand the function of TRIM3 in cataracts.
Dietary Phytochemicals as a Potential Source for Targeting Cancer Stem Cells
Published in Cancer Investigation, 2021
Prasath Manogaran, Devan Umapathy, Manochitra Karthikeyan, Karthikkumar Venkatachalam, Anbu Singaravelu
The spot check to this theory is the CE (clonal evolution) model system suggested that mutated clones have a growth improvement, will enlarge the dominant population. These leading populations of proliferating cells obtain tumorigenesis awaiting new clones with further mutation become dominant through development and proliferation. Although, none of the model system alone can justify the complex biology of cancer progression, resistant to chemotherapeutic drugs and metastasis. Nowadays, more data are available to support the combined model that has been published. Dick and coworkers (22) have suggested that rare cells in acute myeloid leukemia were re-establishing successively transplantable leukemia in murine models (22). Further, Barabé and coworkers (23) have suggested that CSCs have themselves involved in clonal evolution, and karyotyping analysis revealed that clonally derived cells from colon cancer have chromosomal instability in cancer stem cells or CSCs (23). These findings developed a new CSCs hypothesis for both developmental CSCs and clonal evolution contents, allows pre-existing CSCs to transform into secondary CSCs. The two models of CSC ontogeny are not equally elite. Furthermore, to maintain heterogeneity in tumor cells are capable of dividing by two ways namely, asymmetric division as results of one daughter cells and oneself transformed cells but in symmetric division produces two self transformed cells. This concept is often unnoticed since the CSC-hypothesis model can be explained primarily by the concept of asymmetric cell division. In contrast, the CE hypothesis requires pre-existing CSCs to be transformed into secondary CSCs, whereas maintaining inactive main CSCs. Another concept suggested that CSCs were generated from transformed cells or progenitor cells have the property of self-renewal. Two hypotheses seem to be acceptable and later this mechanism was documented in lineage-restricted granule cell progenitors (18,24,25).
Pathophysiology of Meibomian Glands – An Overview
Published in Ocular Immunology and Inflammation, 2021
Jana Dietrich, Fabian Garreis, Friedrich Paulsen
The meibum is mainly produced by the meibocytes, which is released into the ductal system by holocrine secretion. Within the ductal system, the meibum is further modified by hydrolyzing enzymes originated from commensal bacteria.13–15 Lipid secretion is associated with the apoptosis of the meibocytes; thus, the entire cell content is secreted during this process and forms the meibum. To replenish the meibocytes that were loss due to the physiological cell turnover, each meibomian gland needs to harbor specialized stem cells. There exists varying results about the location of these stem cells. On the one hand, proliferating cells were identified by leucine-rich repeats and immunoglobulin-like domain protein 1 (Lrig1) expression or by incorporation of radioactive nucleotide [3 H]-thymidine during cell division.16,17 In these studies, proliferating putative stem cells were detected within the basal cell layer in the periphery of each acini in rat and human meibomian glands. On the other hand, label-retaining cells (LRCs), thus putative stem cells, were found to reside at the interface between the ductal epithelium and the acinus in mouse meibomian glands.18–20 Both observations could be interconnected. Slow-cycling stem cells, thus LRCs, could reside at the transition zone between the ductules and the acinus, as seen by Parfitt et al.19 A characteristic of stem cells is their ability to self-renew with the potential for asymmetric cell division.21–23 Asymmetric cell division results in one daughter cell that is identical to the original stem cell and one daughter cell that is more differentiated. The detected proliferating cells in the periphery of the meibomian acinus, as seen by Olami et al. and Xie et al.16,17 could therefore represent the more differentiated daughter cells derived from asymmetric cell division of the stem cells in the transition zone. However, this relation needs to be investigated in further experiments.
Related Knowledge Centers
- Cell Biology
- Cell Division
- Cell Polarity
- Cell Signaling
- Drosophila Melanogaster
- Spindle Apparatus
- Stem Cell
- Cell
- Model Organism
- Mouse