• BMB Reports
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• v.42 no.5
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• pp.245-259
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• 2009

The process by which adult neural stem cells generate new and functionally integrated neurons in the adult mammalian brain has been intensely studied, but much more remains to be discovered. It is known that neural progenitors progress through distinct stages to become mature neurons, and this progression is tightly controlled by cell-cell interactions and signals in the neurogenic niche. However, less is known about the cell-intrinsic signaling required for proper progression through stages of adult neurogenesis. Techniques have recently been developed to manipulate genes specifically in adult neural stem cells and progenitors in vivo, such as the use of inducible transgenic mice and viral-mediated gene transduction. A critical mass of publications utilizing these techniques has been reached, making it timely to review which molecules are now known to play a cell-intrinsic role in regulating adult neurogenesis in vivo. By drawing attention to these isolated molecules (e.g. Notch), we hope to stimulate a broad effort to understand the complex and compelling cascades of intrinsic signaling molecules important to adult neurogenesis. Understanding this process opens the possibility of understanding brain functions subserved by neurogenesis, such as memory, and also of harnessing neural stem cells for repair of the diseased and injured brain.

• Biomolecules & Therapeutics
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• v.27 no.1
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• pp.78-84
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• 2019

Cell therapeutic agents for treating degenerative brain diseases using neural stem cells are actively being developed. However, few systems have been developed to monitor in real time whether the transplanted neural stem cells are actually differentiated into neurons. Therefore, it is necessary to develop a technology capable of specifically monitoring neuronal differentiation in vivo. In this study, we established a system that expresses cell membrane-targeting red fluorescent protein under control of the Synapsin promoter in order to specifically monitor differentiation from neural stem cells into neurons. In order to overcome the weak expression level of the tissue-specific promoter system, the partial 5' UTR sequence of Creb was added for efficient expression of the cell surface-specific antigen. This system was able to track functional neuronal differentiation of neural stem cells transplanted in vivo, which will help improve stem cell therapies.

• Journal of Life Science
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• v.16 no.5
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• pp.750-758
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• 2006

Calcium-binding protein calretinin is thought to play important roles in calcium buffering. Recently, we reported on the distribution, morphology of calretinin-immunoreactive (IR) neurons and the effects of eye enucleation on the immunoreactivity of calretinin in the superficial layers of the hamster superior colliculus (SC). In the present study, we describe the distributions and types of labeled cells and effects of enucleation in the deeper layers by immunocytochemistry. We also compare this labeling to that of GABA, the major inhibitory neurotransmitter in the central nervous system. In contrast to the superficial layers, the deeper layers contained many calretinin-IR neurons which formed two tiers. The first tier, which was very distinctive, was found within the intermediate gray layer. The second tier was found in the deep gray layer. Labeled neurons varied dramatically in morphology and included vertical fusiform, stellate, round/oval, and horizontal neurons. In contrast to the superficial layers, enucleation appeared to have no effect on the distribution of calretinin immunoreactivity in the deeper layers. Two-color immunofluorescence revealed that none of calretinin-IR neurons were labeled with an antibody to GABA. The present results demonstrate that calretinin identifies unique neuronal sublaminar organizations in the hamster SC. The present results also demonstrate that none of the calretinin-IR neurons in the hamster SC is GABAergic interneurons. As many calretinin-IR cells are GABAergic interneurons in most other brain areas, this phenomenon in hamster SC is exceptional.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.14-23
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• 2002

The nervous system consists of two types of cells, which are neurons and glial cells. Among the glial cells, oligodendrodendrocytes and schwann cells form myelin sheaths in the central nervous system (CNS) and the peripheral nervous system (PNS), respectively. The major function of myelin in vertebrates is to insulate axonal and help action potential travel faster.(omitted)

• Biomolecules & Therapeutics
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• v.27 no.1
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• pp.15-24
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• 2019

Neural stem cells (NSCs) can proliferate and differentiate into multiple cell types that constitute the nervous system. NSCs can be derived from developing fetuses, embryonic stem cells, or induced pluripotent stem cells. NSCs provide a good platform to screen drugs for neurodegenerative diseases and also have potential applications in regenerative medicine. Natural products have long been used as compounds to develop new drugs. In this review, natural products that control NSC fate and induce their differentiation into neurons or glia are discussed. These phytochemicals enable promising advances to be made in the treatment of neurodegenerative diseases.

• Journal of Life Science
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• v.29 no.12
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• pp.1329-1336
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• 2019

Subventricular zone (SVZ) in the brain contains neural stem cells (NSCs) which self-renew and differentiate to neurons and glial cells during postnatal period and throughout adulthood. Since fate decision to either proliferation or differentiation has to respond to intracellular and extracellular conditions, many intrinsic and extrinsic factors are involved. Among them, mitochondria have been reported to participate in fate decision of NSCs. In our previous report, we showed that long-term treatment of a mitochondrial inhibitor rotenone greatly inhibited neurogenesis. In this study, we examined the effects of short-term treatment of rotenone on SVZ NSCs. We found that (1) even one-day treatment of rotenone significantly reduced neurogenesis and earlier time points seemed to be more sensitive to rotenone, (2) a number of Mash1+ transit amplifying cells was decreased by one-day treatment of rotenone, (3) short-term treatment of rotenone eliminated most of the differentiated Tuj1+ neurons and Olig2+ oligodendrocytes, while glial fibrillary acidic protein (GFAP)+ astrocytes were not affected, and (4) sulfiredoxin 1 (Srxn1) gene expression was increased after one-day treatment of rotenone, indicating activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway. All these results confirm that functional mitochondria are necessary during differentiation to neurons or oligodendrocytes as well as maintenance of neurons after differentiation. Also, these data suggest that temporary exposure to mitochondrial inhibitor such as rotenone might have long-term effects on neurogenic potential of NSCs.

• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.431-437
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• 2000

The aim of this study was to evaluate the involvement of CPP32 (caspase-3), one of the death-related enzymes, in the course of experimental autoimmune encephalomyelitis (EAE). EAE was induced in Lewis rats immunized with an emulsion of rat spinal cord homogenate with complete Freunds adjuvant supplemented with Mycobacterium tuberculosis (H37Ra, 5mg/ml). The expression of CPP32 in the spinal cords of rats with EAE was studied. In normal rat spinal cords, CPP32 is constitutively, but weakly, expressed in neurons and some neuroglial cells. In the EAE spinal cords, many inflammatory cells were positive for CPP 32, and the majority of CPP32(+) cells were identified as ED1(+) macrophages. During this stage of EAE, the number of CPP32(+) cells in brain cells, including neurons and astrocytes, increased, and these cells also had increased CPP32 immunoreactivity. CPP32 immunor eactivity was not always matched with apoptosis of inflammatory cells in EAE lesions. We speculate that CPP32, which is constitutlvely expressed in brain cells, increases in response to neuroimmunological stimulation in both brain neuronal cells and inflammatory cells. The functional role of CPP32 in neuroimmunological disorders is discussed.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.79-79
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• 2003

Embryonic stem cells are capable of differentiating into a variety of cell lineages. However, the ultimate results of differentiation in vitro greatly depend on the duration of treatment and kinds of differentiating inducers added. In order to investigate the efficiencies of various differentiation inducers and the methods of treatment, we examined differentiation patterns of human embryonic stem cell (hESC, MB03) according to several different protocols. Exp. I) Upon differentiation using retinoic acid and ascorbic acid (RA/AA), embryoid bodies (EB, for 4days) derived from hESC was exposed to Rh (10$^{-6}$ M) and AA (50 mM) for 4 days, and were allowed to differentiate in N2 medium for 7, 14, 21, or 28 days. Exp. II) When bFGF was used, neuronal precursor cells were selected for 8 days in N2 medium after EB formation. After selection, cells were expanded at the presence of bFGF (20 ng/ml) for another 6 days followed by a final differentiation in N2 medium for 7, 14, 21 or 28 days. Exp. III) In addition, to examine the effects of neurotrophic factors in the production of mature neurons, groups of cells were exposed to either BDNF (5 ng/ml) or TGF-$\alpha$(10 ng/ml) during the 28 days of final differentiation. Differentiation patterns of RA/AA or bFGF treated groups were very similar; approximately 82% and 83% of the cells, respectively, were positive for anti-NF200 antibody, while it was about 10% and 11%, respectively, for anti-NF160 antibody in 28 days in N2 medium. Alsor, cells expressing TH were as low as 5%, while the cells doubled when matured at the presence of either BDNF or TGF-$\alpha$. Cells immunoreactive to anti-GAD antibody were approximately 20%. These results suggest that a maturation step rather than differentiation induction step, which is formation of EB, effects more decisively to the ultimate differentiation pattern.

• Journal of International Academy of Physical Therapy Research
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• v.6 no.2
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• pp.846-851
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• 2015

This neurological damage accelerates the infection reaction of cells and apoptosis at the time of reperfusion after ischemia occurs. BCL-2/BCL-2 allogeneic begeminum has a function of suppressing the apoptosis of cells, and thus it is inferred that the susceptibility of cells to apoptosis is determined by the amount of allogeneic begeminum present which is determined based on the amount of BAX. Ischemia was induced in SD mice by occluding the common carotid artery for 5 minutes, after which blood was re-perfused. NEES was applied to acupuncture points, at 12, 24, and 48 hours post-ischemia on the joksamri, Hapgok. Protein expression was investigated through BAX antibody immuno-reactive cells in the cerebral nerve cells and Western blotting. The results were as follows: In the present study as well, as a result of observation of the change in the number of the BAX reaction cells after the inducement of GI, there was the aspect of most of the BAX reaction cells being observed in the corpus striatum area of the GI group 24 hours after the inducement of ischemia. This revealed the same results as those of previous studies in which the change in the number of BAX reaction cells occurred in all areas while ischemia was in progress. The change in the expression of BAX protein after 24 hours showed that there was a very significant reduction in the NEES group compared to the GI group (p<.01). As a result, a greatest amount of change in the number of BAX immunoreactive cells related to apoptosis 24 hours after ischemia appeared in the NEES group. This study that ischemia increases the expression of BAX that induces apoptosis. Thus, it is determined that ischemia is the main cause of the apoptosis of neurons, and this study reveals that low frequency needle electrode electrical stimulation has the effect of blocking the apoptosis of neurons by reducing protein related to the apoptosis of cells that has increased after ischemia has occurred.

• Animal cells and systems
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• v.2 no.3
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• pp.389-393
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• 1998

We localized a calcium-binding protein, calretinin, in the superior colliculus of the mouse and studied the distribution and effect of eye enucleation on the distribution of this protein. Calretinin was localized with immunocyto-chemistry. A dense plexus of anti-calretinin-labeled fibers was found within the superficial layers. The highest density was found in the deep superficial gray layer. Monocular enucleation produced an almost complete reduction of calretinin-immunoreactive fibers in the superficial layers of the superior colliculus contralateral to the enucleation. Furthermore, many calretinin-labeled cells appeared in the contralateral superior colliculus. These newly appeared neurons had small oval or round cell bodies. The results demonstrate that calretinin identify unique neuronal sublaminar organizations in the superior colliculus of the mouse. They also suggest that the retinal projection may control in part the content of calretinin in some neurons in the superficial layers of the mouse superior colliculus.