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The Journal of Clinical Investigation Jun 2011To fulfill its role as the major energy-storing tissue, adipose has several unique properties that cannot be seen in any other organ, including an almost unlimited... (Review)
Review
To fulfill its role as the major energy-storing tissue, adipose has several unique properties that cannot be seen in any other organ, including an almost unlimited capacity to expand in a non-transformed state. As such, the tissue requires potent mechanisms to remodel, acutely and chronically. Adipocytes can rapidly reach the diffusional limit of oxygen during growth; hypoxia is therefore an early determinant that limits healthy expansion. Proper expansion requires a highly coordinated response among many different cell types, including endothelial precursor cells, immune cells, and preadipocytes. There are therefore remarkable similarities between adipose expansion and growth of solid tumors, a phenomenon that presents both an opportunity and a challenge, since pharmacological interventions supporting healthy adipose tissue adaptation can also facilitate tumor growth.
Topics: Adaptation, Physiological; Adipocytes; Adipose Tissue; Animals; Cell Division; Cell Hypoxia; Cell Size; Endothelial Cells; Energy Metabolism; Extracellular Matrix; Fatty Acids; Humans; Inflammation; Macrophages; Mice; Mice, Transgenic; Neovascularization, Physiologic; Obesity; Weight Loss
PubMed: 21633177
DOI: 10.1172/JCI45887 -
Cell Feb 2019Cell size varies greatly between cell types, yet within a specific cell type and growth condition, cell size is narrowly distributed. Why maintenance of a cell-type...
Cell size varies greatly between cell types, yet within a specific cell type and growth condition, cell size is narrowly distributed. Why maintenance of a cell-type specific cell size is important remains poorly understood. Here we show that growing budding yeast and primary mammalian cells beyond a certain size impairs gene induction, cell-cycle progression, and cell signaling. These defects are due to the inability of large cells to scale nucleic acid and protein biosynthesis in accordance with cell volume increase, which effectively leads to cytoplasm dilution. We further show that loss of scaling beyond a certain critical size is due to DNA becoming limiting. Based on the observation that senescent cells are large and exhibit many of the phenotypes of large cells, we propose that the range of DNA:cytoplasm ratio that supports optimal cell function is limited and that ratios outside these bounds contribute to aging.
Topics: Candida albicans; Cell Cycle; Cell Enlargement; Cell Proliferation; Cell Size; Cellular Senescence; Cytoplasm; Fibroblasts; HEK293 Cells; Humans; Primary Cell Culture; Saccharomyces cerevisiae; Saccharomycetales; Signal Transduction
PubMed: 30739799
DOI: 10.1016/j.cell.2019.01.018 -
Medical Microbiology and Immunology Oct 2019The early stage of oncogenesis is linked to the disorder of the cell cycle. Abnormal gene expression often leads to cell cycle disorders, resulting in malignant... (Review)
Review
The early stage of oncogenesis is linked to the disorder of the cell cycle. Abnormal gene expression often leads to cell cycle disorders, resulting in malignant transformation of human cells. Epstein-Barr virus (EBV) is associated with a diverse range of human neoplasms, such as malignant lymphoma, nasopharyngeal carcinoma and gastric cancer. EBV mainly infects human lymphocytes and oropharyngeal epithelial cells. EBV is latent in lymphocytes for a long period of time, is detached from the cytoplasm by circular DNA, and can integrate into the chromosome of cells. EBV expresses a variety of latent genes during latent infection. The interaction between EBV latent genes and oncogenes leads to host cell cycle disturbances, including the promotion of G/S phase transition and inhibition of cell apoptosis, thereby promoting the development of EBV-associated neoplasms. Molecular mechanisms of EBV-driven cell cycle progression and oncogenesis involve diverse genes and signal pathways. Here, we review the molecular mechanisms of EBV-driven cell cycle progression and promoting oncogenesis.
Topics: Carcinogenesis; Cell Proliferation; Cell Transformation, Neoplastic; Epithelial Cells; Herpesvirus 4, Human; Host-Pathogen Interactions; Humans; Lymphocytes
PubMed: 30386928
DOI: 10.1007/s00430-018-0570-1 -
Pharmacology & Therapeutics Sep 2013Microglia are critical nervous system-specific cells influencing brain development, maintenance of the neural environment, response to injury, and repair. They... (Review)
Review
Microglia are critical nervous system-specific cells influencing brain development, maintenance of the neural environment, response to injury, and repair. They contribute to neuronal proliferation and differentiation, pruning of dying neurons, synaptic remodeling and clearance of debris and aberrant proteins. Colonization of the brain occurs during gestation with an expansion following birth with localization stimulated by programmed neuronal death, synaptic pruning, and axonal degeneration. Changes in microglia phenotype relate to cellular processes including specific neurotransmitter, pattern recognition, or immune-related receptor activation. Upon activation, microglia cells have the capacity to release a number of substances, e.g., cytokines, chemokines, nitric oxide, and reactive oxygen species, which could be detrimental or beneficial to the surrounding cells. With aging, microglia shift their morphology and may display diminished capacity for normal functions related to migration, clearance, and the ability to shift from a pro-inflammatory to an anti-inflammatory state to regulate injury and repair. This shift in microglia potentially contributes to increased susceptibility and neurodegeneration as a function of age. In the current review, information is provided on the colonization of the brain by microglia, the expression of various pattern recognition receptors to regulate migration and phagocytosis, and the shift in related functions that occur in normal aging.
Topics: Aging; Animals; Brain; Cell Differentiation; Cell Movement; Cell Proliferation; Humans; Microglia; Nerve Degeneration; Neurons; Phagocytosis
PubMed: 23644076
DOI: 10.1016/j.pharmthera.2013.04.013 -
Cold Spring Harbor Perspectives in... May 2015In this work, we review progress made in understanding the molecular underpinnings of growth and division in mycobacteria, concentrating on work published since the last... (Review)
Review
In this work, we review progress made in understanding the molecular underpinnings of growth and division in mycobacteria, concentrating on work published since the last comprehensive review ( Hett and Rubin 2008). We have focused on exciting work making use of new time-lapse imaging technologies coupled with reporter-gene fusions and antimicrobial treatment to generate insights into how mycobacteria grow and divide in a heterogeneous manner. We try to reconcile the different observations reported, providing a model of how they might fit together. We also review the topic of mycobacterial spores, which has generated considerable discussion during the last few years. Resuscitation promoting factors, and regulation of growth and division, have also been actively researched, and we summarize progress in these areas.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Cell Division; Cell Enlargement; Chromosomes, Bacterial; Diagnostic Imaging; Drug Resistance, Bacterial; Mycobacterium; Spores, Bacterial
PubMed: 25957314
DOI: 10.1101/cshperspect.a021097 -
Current Opinion in Microbiology Dec 2016
Topics: Cell Proliferation; Prokaryotic Cells
PubMed: 27720364
DOI: 10.1016/j.mib.2016.09.001 -
International Journal of Molecular... Jun 2016Stem cells are responsible for the organ and tissue development, growth and maintenance from embryonic stage up to late adult life.[...].
Stem cells are responsible for the organ and tissue development, growth and maintenance from embryonic stage up to late adult life.[...].
Topics: Animals; Cell Differentiation; Epigenesis, Genetic; Growth; Humans; Stem Cells
PubMed: 27347939
DOI: 10.3390/ijms17071005 -
Current Biology : CB Sep 2017Land plants are called 'embryophytes' and thus, their collective name is defined by their ability to form embryos. Indeed, embryogenesis is a widespread phenomenon in...
Land plants are called 'embryophytes' and thus, their collective name is defined by their ability to form embryos. Indeed, embryogenesis is a widespread phenomenon in plants, and much of our diet is composed of embryos (just think of grains, beans or nuts; Figure 1). However, in addition to embryos as a source of nutrition, they are also a fascinating study object. Some of the most fundamental decisions on fate and identity, as well as patterning and morphogenesis, are taken during the first days of plant life. Yet, embryos are diverse in structure and function, and embryogenesis in plants is by no means restricted to the zygote - the product of fertilization. In this Primer, we discuss the adventures of the young plant. We will consider what it means to be a plant embryo and how to become one. We will next highlight how the study of early embryogenesis can reveal principles underlying oriented cell division and developmental pattern formation in plants.
Topics: Cell Division; Morphogenesis; Plant Cells; Plants; Seeds
PubMed: 28898655
DOI: 10.1016/j.cub.2017.05.026 -
Current Biology : CB Mar 2017Basement membranes (BMs) are thin, dense sheets of specialized, self-assembled extracellular matrix that surround most animal tissues (Figure 1, top). The emergence of...
Basement membranes (BMs) are thin, dense sheets of specialized, self-assembled extracellular matrix that surround most animal tissues (Figure 1, top). The emergence of BMs coincided with the origin of multicellularity in animals, suggesting that they were essential for the formation of tissues. Their sheet-like structure derives from two independent polymeric networks - one of laminin and one of type IV collagen (Figure 1, bottom). These independent collagen and laminin networks are thought to be linked by several additional extracellular matrix proteins, including nidogen and perlecan (Figure 1, bottom). BMs are usually associated with cells and are anchored to cell surfaces through interactions with adhesion receptors and sulfated glycolipids (Figure 1, bottom). Various combinations of other proteins, glycoproteins, and proteoglycans - including fibulin, hemicentin, SPARC, agrin, and type XVIII collagen - are present in BMs, creating biochemically and biophysically distinct structures that serve a wide variety of functions. BMs have traditionally been viewed as static protein assemblies that provide structural support to tissues. However, recent studies have begun to uncover dynamic, active roles for BMs in many developmental processes. Here, we discuss established and emerging roles of BMs in development, tissue construction, and tissue homeostasis. We also explore how cells traverse BM barriers, the roles of BMs in human diseases, and future directions for the field.
Topics: Animals; Basement Membrane; Caenorhabditis elegans; Disease Susceptibility; Drosophila; Growth; Homeostasis; Humans; Mice
PubMed: 28324731
DOI: 10.1016/j.cub.2017.02.006 -
The New Phytologist Jul 2021Cell division in plants is particularly important as cells cannot rearrange. It therefore determines the arrangement of cells (topology) and their size and shape... (Review)
Review
Cell division in plants is particularly important as cells cannot rearrange. It therefore determines the arrangement of cells (topology) and their size and shape (geometry). Cell division reduces mechanical stress locally by producing smaller cells and alters mechanical properties by reinforcing the mechanical wall network, both of which can alter overall tissue morphology. Division orientation is often regarded as following geometric rules, however recent work has suggested that divisions align with the direction of maximal tensile stress. Mechanical stress has already been shown to feed into many processes of development including those that alter mechanical properties. Such an alignment may enable cell division to selectively reinforce the cell wall network in the direction of maximal tensile stress. Therefore there exists potential feedback between cell division, mechanical stress and growth. Improving our understanding of this topic will help to shed light on the debated role of cell division in organ scale growth.
Topics: Biophysics; Cell Division; Cell Wall; Plant Development; Stress, Mechanical
PubMed: 33774836
DOI: 10.1111/nph.17369