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Neurogenesis in the Adult and Aging Brain
Published in David R. Riddle, Brain Aging, 2007
David R. Riddle, Robin J. Lichtenwalner
Determining whether the size of the population of stem and progenitor cells declines with aging is as challenging as quantifying cell cycle changes, and recent attempts to answer the question have provided intriguing but somewhat conflicting results. Tropepe et al. [61] reported that progenitor cells isolated from young adult and aged mice formed comparable numbers of, and similarly sized, neurospheres in vitro, leading the authors to conclude that both the number and proliferative potential of progenitor cells is maintained during aging, and that the aging-related decline in proliferation in vivo is due solely to changes in the microenvironment in which progenitor cells proliferate. A more recent study, however, demonstrated a twofold reduction in the number of neurospheres recovered in culture from old relative to young adult mice [77]. Consistent with that study, Luo and colleagues [64] combined BrdU labeling, immunolabeling for Ki-67 (a nuclear protein expressed by dividing cells), and ultrastructural analysis to analyze the number of neuroblasts and TAP cells and reported that both decrease by middle age. Quantifying the population of slowly cycling stem cells is more difficult than analyzing the “later” progenitor cells, but there also is evidence for an aging-related decrease in the number of neural stem cells in the SVZ, based on labeling for the G1-phase cell cycle marker Mcm2 and labeling with nucleoside analogs [77, 78]. The magnitude of the reported declines in stem cells, neuroblasts, and TAP cells is similar to the decline in BrdU labeling (approximately 50%) and, like the decline in cell division, most of the decrease in progenitor cell number occurs by middle age. In considering these and similar studies, it is important to remember that there are no definitive, state-independent markers for neural progenitor cells, and that a “loss” of cells based on immunolabeling or morphological criteria could simply reflect loss of expression of specific phenotypic traits. The ability of progenitor cells in aged animals to respond to a variety of stimuli and return neurogenesis to levels at or near that seen in young adults [56–58, 62, 72, 79–82] demonstrates that even in the aged brain there is a population of neural progenitor cells that is adequate to maintain neurogenesis at a youthful level, given the proper conditions.
Adipose Tissue-Derived Adult Stem Cells
Published in Richard K. Burt, Alberto M. Marmont, Stem Cell Therapy for Autoimmune Disease, 2019
Laura Aust, Lyndon Cooper, Blythe Devlin, Tracey du Laney, Sandra Foster, Jeffrey M. Gimble, Farshid Guilak, Yuan Di C. Halvorsen, Kevin Hicok, Amy Kloster, Henry E. Rice, Anindita Sen, Robert W. Storms, William O. Wilkison
Cellular therapeutics are exciting and potentially powerful tools for the treatment of neurological disorders.51 The generation of neuronal stem cells would revolutionize the therapy of neurologic diseases.51 Brain derived stem cells and embryonic stem cells have been successfully isolated and differentiated in vitro and in vivo toward a range of neuronal phenotypes.51 Brain cells are relatively inaccessible and moral and ethical considerations limit the use of embryonic stem cells for therapeutic application. Recently, bone marrow stromal derived adult stem cells were differentiated toward a neuro/glial phenotype both in vitro and in vivo.52,53 Woodbury et al developed a differentiation cocktail containing an antioxidant (either butylated hydroxyanisole or 2-mercaptoethanol) to induce neuronal differentiation.53 Upon exposure to the neuronal differentiation conditions in the presence of antioxidant, valproic acid, forskolin, and insulin, human ADAS cells are able to undergo rapid morphological reorganization toward a neuronal/glial phenotype.5 Within several hours following neuronal induction, ADAS cells begin to exhibit morphologic changes consistent with neuronal differentiation. Immunohistochemical characterization of induced ADAS cells demonstrated that they express protein markers associated with a neuronal cell fate including the preneuron marker protein nestin, intermediate filament M, and the differentiated neuron nuclear protein.54 Examination by Western blot analysis has confirmed the expression of several neuronal proteins following neuronal induction of human ADAS cells, including nestin, NeuN, and glial cell marker protein glial fibrillary acidic protein (GFAP) by 24 hours of induction. Exposure of the ADAS cells to bFGF and EGF augmented the neuronal induction of ADAS cells. Finally, when the ADAS cells are cultured on neuro-supportive substrates the cells rapidly reorganize to form neurospherelike structures. Neurosphere formation is one of the classic characteristics attributed to neuronal stem cells. The neurospherelike structures formed by ADAS cells contain nestin and NeuN positive cells (unpublished observations). Clonal analysis of cells derived from these structures will help determine ADAS cells’ capacity to generate functional neuronal cells.
Recent advances in cellular models for discovering prion disease therapeutics
Published in Expert Opinion on Drug Discovery, 2022
Lea Nikolić, Chiara Ferracin, Giuseppe Legname
Neurospheres are aggregates of stem cells that can be generated from either embryonic stem cells or neural stem and progenitor cells isolated from the central nervous system (CNS) [84]. Starting population of cells is plated as a single-cell suspension, supplemented with the medium containing fibroblast growth factor and/or epidermal growth factor. Each generated neurosphere contains cells at various stages of differentiation, including stem cells as well as proliferating neural progenitor cells and postmitotic neurons and glia [85]. This is one of the most important advantages of this system as other 2D models discussed here contain only one or two different cell types, which is not representative of intercellular connections seen in vivo . Other advantages of this system are its self-renewable properties and lack of artificial manipulation.
The effects of minocycline on proliferation, differentiation and migration of neural stem/progenitor cells
Published in International Journal of Neuroscience, 2020
Fatemeh Shamsi, Zahra Zeraatpisheh, Hamed Alipour, Abbas Nazari, Hadi Aligholi
The diameter of neurospheres was also measured as an index of proliferation. In 2-Dcultures, the cells treated whit 10 μg/ml of minocycline formed the largest neurospheres while they were not considerably bigger than those of control group and those treated by 1 μg/ml of minocycline. On the other hand, higher doses of the drug had an adverse effect on the diameter of neurospheresso that the neurospheres treated with 100 μg/ml of drug (38.6 ± 2.4) were significantly smaller than that of control (68.1 ± 9.2), 1 μg/ml (68.7 ± 19.8) and 10 μg/ml-treated (78.9 ± 33.7) groups (p < 0.05). 50 μg/ml of minocycline (46.4 ± 15.6) also reduced the size of neurospheres remarkably but the difference was statistically significant only compared to 10 μg/ml (78.9 ± 33.7) of minocycline(p < 0.05; Figure 3(a)).
Silver nanoparticles induce neurotoxicity in a human embryonic stem cell-derived neuron and astrocyte network
Published in Nanotoxicology, 2018
Neza Repar, Hao Li, Jose S. Aguilar, Qingshun Quinn Li, Damjana Drobne, Yiling Hong
Human glutamatergic neurons and astrocytes were generated as previously described (Begum et al. 2015). Briefly, hESCs were treated with collagenase IV (2 mg/mL, Life Technologies, Carlsbad, CA), harvested, plated onto low adhesion suspension culture plates (Olympus plastic) in KnockOut™ Serum Replacement medium (KRSM) and incubated in 10% CO2 for 5 days for neurosphere formation. The KRSM is supplemented with basic fibroblast growth factor (10 ng/mL), epidermal growth factor (0.5 ng/mL), and heparin (1 µg/mL). Neurospheres were incubated in 5% CO2 for 7 days, and the KSRM medium was gradually replaced with neuronal maintenance medium (NMM) by changing the medium every other day. Neurospheres were collected, treated with Gentle Cell Dissociation Reagent (Stem Cell Technologies, catalog no. 07174) to break them down into smaller fragments, and then transferred to Matrigel-coated plates containing NMM. After 6 days, cells were plated on Matrigel-coated plates. Cells were maintained in NMM until neurons and astrocytes appeared in the culture (2–3 weeks).