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

• BMB Reports
• /
• v.46 no.8
• /
• pp.383-390
• /
• 2013

Mammalian neural stem cells (NSCs) are of particular interest because of their role in brain development and function. Recent findings suggest the intimate involvement of programmed cell death (PCD) in the turnover of NSCs. However, the underlying mechanisms of PCD are largely unknown. Although apoptosis is the best-defined form of PCD, accumulating evidence has revealed a wide spectrum of PCD encompassing apoptosis, autophagic cell death (ACD) and necrosis. This mini-review aims to illustrate a unique regulation of PCD in NSCs. The results of our recent studies on autophagic death of adult hippocampal neural stem (HCN) cells are also discussed. HCN cell death following insulin withdrawal clearly provides a reliable model that can be used to analyze the molecular mechanisms of ACD in the larger context of PCD. More research efforts are needed to increase our understanding of the molecular basis of NSC turnover under degenerating conditions, such as aging, stress and neurological diseases. Efforts aimed at protecting and harnessing endogenous NSCs will offer novel opportunities for the development of new therapeutic strategies for neuropathologies.

• The Journal of Korean Physical Therapy
• /
• v.23 no.1
• /
• pp.59-66
• /
• 2011

Purpose: The purpose of this study was to investigate the effect of electroacupuncture on pain threshold and 5-HT synthesis in raphe magnus nucleus of dog brain stem following nociception induced by 1% carageenan. Method: Twenty male dogs were randomly divided into two groups, a control group and an electroacupuncture group with the following parameters: ST36, LI11 and SP9 with 120Hz and 0.5mA. The dogs were sacrificed at 30, 60, 90, 120, 150 and 180 min after nociception using 1% carageenan injection into the plantar side of the dog's left leg. The pain threshold was recorded by an Analgesia-meter. After making brain slice sections, the tissues were immunostained with 5-HT antisera (1:2,500). Results: The pain threshold for the electroacupuncture group was higher than for the control group. The number of 5-HT immunoreactive neurons in the electroacupuncture group was greater than that of the control group. Differences between the two groups regarding the number of 5-HT immunoreactive neurons at 30 min and 60 min (p<0.05), at 120 min and 150 min (p<0.01), and at 8 days (p<0.05) were significant. Conclusion: The increases in pain threshold and number of 5-HT immunoreactive neurons in the raphe magnus nucleus of dog brain stem showed that electroacupuncture can attenuate pain transduction through the descending tract.

• STI Policy Review
• /
• v.5 no.2
• /
• pp.43-64
• /
• 2014

Korea has pursued an aggressive policy of inviting more foreign-born students to its universities since the late 1990s in the wake of the globalization of education markets and its changing demographic structure. While increasingly more students from Asia come to Korea for study, more than half of the graduates return home upon graduation. Given the issues of brain drain, brain circulation, and knowledge transfer that are raised by such a high return rate, this paper examines the factors that frame the foreign students' decision on their post-graduation careers. By analyzing survey data, we report that Asian students majoring in science, technology, engineering, and mathematics (STEM) are more likely to return than non-STEM majors. This suggests that Korea's aggressive policies of inviting foreign-born students have contributed to brain circulation and knowledge transfer between Korea and the other Asian countries. We also find that scholarships from Korean sources and positive attitudes toward Korean culture and life increase their inclination to stay in the country upon graduation. These findings, however, raise more questions than answers, since it becomes obvious that their post-graduation decisions are highly affected by what Korea as a society provides.

• Clinical and Experimental Pediatrics
• /
• v.48 no.8
• /
• pp.806-812
• /
• 2005

Repair mechanisms in the postnatal and mature central nervous system(CNS) have long been thought to be very limited. However recent works have shown that the mature CSN contains neural progenitors, precursors, and stem cells that are capable of generating new neurons, astrocytes, and oligodendrocytes especially in germinative areas such as the subventricular zone of the lateral ventricles, the dentate gyrus of the hippocampus. These findings raise the possibilities for the development of novel neural repair strategies via mobilization and replacement for dying neurons of neural stem cells in situ. Indeed recent reports have provided evidences that endogenous stem cells are activated in response to various injuries, and in some injury models, limited neuronal replacement occurs in the CNS. Here, current understandings for endogenous neurogenesis and induction neurogeneis in postnatal CNS including neonatal brain are summarized and discussed.

• The Korean Journal of Physiology and Pharmacology
• /
• v.16 no.6
• /
• pp.405-411
• /
• 2012

The spontaneous axon regeneration of damaged neurons is limited after spinal cord injury (SCI). Recently, mesenchymal stem cell (MSC) transplantation was proposed as a potential approach for enhancing nerve regeneration that avoids the ethical issues associated with embryonic stem cell transplantation. As SCI is a complex pathological entity, the treatment of SCI requires a multipronged approach. The purpose of the present study was to investigate the functional recovery and therapeutic potential of human MSCs (hMSCs) and polymer in a spinal cord hemisection injury model. Rats were subjected to hemisection injuries and then divided into three groups. Two groups of rats underwent partial thoracic hemisection injury followed by implantation of either polymer only or polymer with hMSCs. Another hemisection-only group was used as a control. Behavioral, electrophysiological and immunohistochemical studies were performed on all rats. The functional recovery was significantly improved in the polymer with hMSC-transplanted group as compared with control at five weeks after transplantation. The results of electrophysiologic study demonstrated that the latency of somatosensory-evoked potentials (SSEPs) in the polymer with hMSC-transplanted group was significantly shorter than in the hemisection-only control group. In the results of immunohistochemical study, ${\beta}$-gal-positive cells were observed in the injured and adjacent sites after hMSC transplantation. Surviving hMSCs differentiated into various cell types such as neurons, astrocytes and oligodendrocytes. These data suggest that hMSC transplantation with polymer may play an important role in functional recovery and axonal regeneration after SCI, and may be a potential therapeutic strategy for SCI.

• BMB Reports
• /
• v.55 no.4
• /
• pp.204-204
• /
• 2022

• BMB Reports
• /
• v.51 no.2
• /
• pp.79-84
• /
• 2018

Niemann-Pick type C disease (NP-C) is a fatal neurodegenerative disorder caused by a deficiency of NPC1 gene function, which leads to severe neuroinflammation such as astrogliosis. While reports demonstrating neuroinflammation are prevalent in NP-C, information about the onset and progression of cerebellar astrogliosis in this disorder is lacking. Using gene targeting, we generated vascular endothelial growth factor (VEGF) conditional null mutant mice. Deletion of VEGF in cerebellar Purkinje neurons (PNs) led to a significant increase of astrogliosis in the brain of NP-C mice in addition to the loss of PNs, suggesting PN-derived VEGF as an important factor in NP-C pathology. Moreover, replenishment of VEGF in neurons improved brain pathology in NP-C mice. Overall, our data provide a new pathological perspective on cerebellar astrogliosis in NP-C and suggest the importance of VEGF as a therapeutic target for this disease.

• Animal cells and systems
• /
• v.8
• /
• pp.18-18
• /
• 2004

• Journal of Korean Neurosurgical Society
• /
• v.42 no.2
• /
• pp.118-124
• /
• 2007

Objective : Adipose tissue is derived from the embryonic mesoderm and contains a heterogenous stromal cell population. Authors have tried to verify the characteristics of stem cell of adipose derived stromal cells (ADSCs) and to investigate immunohistochemical findings after transplantation of ADSC into rat brain to evaluate survival, migration and differentiation of transplanted stromal cells. Methods : First ADSCs were isolated from human adipose tissue and induced adipose, osseous and neuronal differentiation under appropriate culture condition in vitro and examined phenotypes profile of human ADSCs in undifferentiated states using flow cytometry and immunohistochemical study. Human ADSCs were transplanted into the healthy rat brain to investigate survival, migration and differentiation after 4 weeks. Results : From human adipose tissue, adipose stem cells were harvested and subcultured for several times. The cultured ADSCs were differentiated into adipocytes, osteoctye and neuron-like cell under conditioned media. Flow cytometric analysis of undifferentiated ADSCs revealed that ADSCs were positive for CD29, CD44 and negative for CD34, CD45, CD117 and HLA-DR. Transplanted human ADSCs were found mainly in cortex adjacent to injection site and migrated from injection site at a distance of at least 1 mm along the cortex and corpus callosum. A few transplanted cells have differentiated into neuron and astrocyte. Conclusion : ADSCs were differentiated into multilineage cell lines through transdifferentiation. ADSCs were survived and migrated in xenograft without immunosuppression. Based on this data, ADSCs may be potential source of stem cells for many human disease including neurologic disorder.