• BMB Reports
• /
• 제42권5호
• /
• 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.

• Molecules and Cells
• /
• 제27권4호
• /
• pp.397-401
• /
• 2009

Olig2 transcription factor is widely expressed throughout the central nervous system; therefore, it is considered to have multiple functions in the developing, mature and injured brain. In this mini-review, we focus on Olig2 in the forebrain (telencephalon and diencephalon) and discuss the functional significance of Olig2 and the differentiation properties of Olig2-expressing progenitors in the development and injured states. Short- and long-term lineage analysis in the developing forebrain elucidated that not all late Olig2+ cells are direct cohorts of early cells and that Olig2 lineage cells differentiate into neurons or glial cells in a region- and stage-dependent manner. Olig2-deficient mice revealed large elimination of oligodendrocyte precursor cells and a decreased number of astrocyte progenitors in the dorsal cortex, whereas no reduction in the number of GABAergic neurons. In addition to Olig2 function in the developing cortex, Olig2 is also reported to be important for glial scar formation after injury. Thus, Olig2 can be essential for glial differentiation during development and after injury.

• Reproductive and Developmental Biology
• /
• 제35권1호
• /
• pp.9-15
• /
• 2011

The functional cardiovascular system is comprised of distinct mesoderm-derived lineages including endothelial cells, vascular smooth muscle cells and other mesenchymal cells. Recent studies in the human embryonic stem cell differentiation model have provided evidence indicating that these cell lineages are developed from the common progenitors such as hemangioblasts and cardiovascular progenitor cells. Also, the studies have suggested that these progenitors have a common primordial progenitor, which expresses KDR (human Flk-1, also known as VEGFR2, CD309). We demonstrate here that sustained activation of BMP4 (bone morphogenetic protein 4) in hESC line, CHA15 hESC results in $KDR^+$ mesoderm specific differentiation. To determine whether the $KDR^+$ population derived from hESCs enhances potential to differentiate along multipotential mesodermal lineages than undifferentiated hESCs, we analyzed the development of the mesodermal cell types in human embryonic stem cell differentiation cultures. In embryoid body (EB) differentiation culture conditions, we identified an increased expression of $KDR^+$ population from BMP4-stimulated hESC-derived EBs. After induction with additional growth factors, the $KDR^+$ population sorted from hESCs-derived EBs displays mesenchymal, endothelial and vascular smooth muscle potential in matrix-coated monolayer culture systems. The populations plated in monolayer cultures expressed increased levels of related markers and exhibit a stable/homologous phenotype in culture terms. In conclusion, we demonstrate that the $KDR^+$ population is stably isolated from CHA15 hESC-derived EBs using BMP4 and growth factors, and sorted $KDR^+$ population can be utilized to generate multipotential mesodermal progenitors in vitro, which can be further differentiated into cardiovascular specific cells.

• 천문학회보
• /
• 제38권2호
• /
• pp.51.1-51.1
• /
• 2013

Submillimeter galaxies are the progenitors of massive galaxy formation, and therefore their interaction with the early intergalactic medium must be an important subject in the cosmology and galaxy astrophysics. However, their detailed relation between the galaxies and surrounding environments is still largely unknown. In this poster, we will present the characteristics of their surrounding environments of a large sample of mm-detected submillimeter galaxies. We will also discuss the proposal for the future observations of these galaxies and their environments using the ALMA and the GMT.

• 천문학회지
• /
• 제29권spc1호
• /
• pp.215-216
• /
• 1996

The wind-formed features observed in the early SNe spectra type II and Ia give an evidence of the existence of an ellipsoidal shell formed by the stellar wind prior to the explosion. Such non-spherical shell can occur not only at scales of parsec (the case of SN 1987 A progenitor), but at the scales of 1000 times less. Such shells can be the result of the radial pulsation. The prolate multi-shell structures are interpreted as a result of a pulsation processes with recurrent wind ejections with velocity increasing.

• 천문학회보
• /
• 제37권2호
• /
• pp.232.2-232.2
• /
• 2012

Submillimeter Galaxies (SMGs) are high-redshift galaxies undergone extremely intense starbursts. Their UV radiation is heavily extinguished by dust and is re-radiated in the far-IR and submillimeter. They are thought to be progenitors of present-day giant elliptical galaxies and can be tracers of the highest density environment at high redshift. However, because of the low angular resolution of existing single-dish submillimeter telescopes, the progress in understanding the SMG population has been remarkably slow. In this talk, I will outline the outstanding issues in this field, and introduce our Submillimeter Array interferometric studies of SMGs. I will also discuss possible new research that will be enabled by next-generation instruments such as ALMA and LMT.

• Biomolecules & Therapeutics
• /
• 제29권6호
• /
• pp.697-697
• /
• 2021

• 한국임상수의학회지
• /
• 제8권1호
• /
• pp.1-10
• /
• 1991

The B-lymphocyte differentiation from committed B-cell progenitors to antibody-secreting cells was discussed. B-cell progenitors derived from hematopoietic stem cells undergo the rearrangement of immunoglobulin(Ig) gene. The earliest cells as B-cell precursors have cytoplasmic Is(${\mu}$ chain). The entire Is molecule is expressed on the surface after synthesis of L chain. The resting B cells(Go stage) stimulated by binding antigen via Ig-receptors are activated(G$_1$ stage) and followed by proliferation(S stage), coupled with further selection(affinity maturation. class switch). The production of antibody against a particular antigen depends on the activation of B cells with surface Is capable of reacting with that antigen. This process does not occur in isolation but is controlled by helper and suppressor T cells and antigen presenting cells(APC). The mechanism of T cell-dependent B-cell response for production of antibody is largely explained by the cell to cell cooperation and soluble helper factors of T cells. 1) The antigen specific B cells and helper T cells are linked by Is-receptors, leading to the delivery of helper signals to the B cells. 2) Helper T cells recognize the processed antigen-derived peptides with the MHC class II molecules(la antigen) and is stimulated to secrete B-cell proliferation and differentiation factors which activate B cells of different antigenic specificity. The two models are shown currently 1) At low antigen concentration, only the antigen-specific B cell binds antigen and presents antigen-derived peptides with la molecules to helper T cells, which are stimulated to secrete cytokines(IL-4, IL-5, etc.) and 2) At high antigen concentration, antigen-derived peptides are presented by specific B cells, by B cells that endocytose the antigens, as well as by APC Cytokines secreted from helper T cells also lead to the activation of B cells and even bystander B cells in the on- vironmment and differentiate them into antibody-secreting plasma cells.

• Molecules and Cells
• /
• 제38권1호
• /
• pp.89-94
• /
• 2015

The shape and activity of mitochondria are tightly regulated by fusion and fission processes that are essential for maintaining normal cellular function. However, little is known about the involvement of mitochondrial dynamics in the development of the immune system. In this study, we demonstrate that mitochondrial dynamics play a role in the differentiation and migration of immature dendritic cells (imDCs). We show that mitochondrial elongation is induced during GM-CSF-stimulated differentiation of bone marrow progenitors to imDCs accompanied by upregulation of mitochondrial fusion proteins. These processes precede the changes in mitochondrial morphology and connectivity that occur during differentiation. Mfn2 and OPA1, but not Mfn1, are transcriptionally upregulated during differentiation; however, knockdown of Mfn2 and OPA1 does not induce any change in expression of CD11c, CDC80, or CD86. Notably, knockdown of Mfn2 or OPA1 by siRNA in imDCs significantly reduces CCR7 expression and CCL19-mediated migration. These results suggest that the mitochondrial fusion-related proteins Mfn2 and OPA1 are upregulated during bone marrow progenitor differentiation and promote the migration of imDCs by regulating the expression of CCR7.

• 고려인삼학회:학술대회논문집
• /
• 고려인삼학회 2002년도 학술대회지
• /
• pp.522-530
• /
• 2002

We have already known, neural progenitor cells exist not only in the developing brain, but in certain spots in adult CNS in mammals, so it will be of great value to find out some compounds which can interfere these cells proliferation ability. In this research, we observed that ginsenoside $Rg_1$ can not only enhance neural progenitors' proliferation ability in vitro, but increase neurogenesis in adult mouse dentate gyrus in vivo. Firstly, we set up neural progenitor cells' culture system from embryonic rats' hippocampus and prove their feature through immunocytochemistry. Then by using MTT assay, we found that when growing with ginsenoside $Rg_1(0.5\~2.5{\mu}mol/l)$, the progenitor cells' survival rate nearly doubled, furthermore, we proved that this increase was due to the increment of cell proliferation through $^3H-thimidine$ incorporation assay, hence, we drew the first conclusion: ginsenoside Rg1 has the ability to stimulate neural progenitor cells' proliferation in vitro; in order to observe this compound's effect in vivo, we devised the following experiment: after administering ginsenoside Rg1 (5, 10 mg/kg, once a day) intraperitoneally for two weeks, we examine the number of BrdU positive cells in the dentate gyrus of mice, and found that Rg1 could increase the number of proliferation cells significantly in vivo. From these studies, we are quite sure about Rg1's effects on the proliferation ability of neural progenitor cells both in vitro and in vivo, certain targets of the compound and its underlying mechanisms are in progress.