• 생약학회지
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• 제46권1호
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• pp.52-58
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• 2015

Neural stem cells (NSCs), with self-renewal and neuronal differentiation capacity, are a feasible resource in cell-based therapies for various neurodegenerative diseases and neural tissue injuries. In this study, we investigated the effects of Schisandrae Fructus (SF) on proliferation and differentiation of human embryonic NSCs. Treatment with 70% ethanol extract of SF increased the viability of NSCs derived from human embryonic stem cells, which was accompanied by increased mRNA expression of cyclin D1. Whereas 70% ethanol extract of SF also decreased the mRNA expression of nestin, it increased class III ${\beta}$-tublin (Tuj-1) and MAP2 in both growth and differentiation media. Lastly, we found increased mRNA expression of BDNF in SF-treated NSCs. In conclusion, our study demonstrates for the first time that SF induced proliferation and neuronal differentiation of NSCs and increased mRNA expression of BDNF, suggesting its potential as a regulator of NSC fate in NSC-based therapy for neuronal injuries from various diseases.

• Anatomy and Cell Biology
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• 제56권4호
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• pp.508-517
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• 2023

In cancer patients, chemo/radio therapy may cause infertility by damaging the spermatogenesis affecting the self-renewal and differentiation of spermatogonial stem cells (SSCs). In vitro differentiation of stem cells especially mesenchymal stem cells (MSCs) into germ cells has recently been proposed as a new strategy for infertility treatment. The aim of this study was to evaluate the proliferation and differentiation of SSCs using their co-culture with Sertoli cells and conditioned medium (CM) from adipose tissue-derived MSCs (AD-MSCs). Testicular tissues were separated from 2-7 days old neonate Wistar Rats and after mechanical and enzymatic digestion, the SSCs and Sertoli cells were isolated and cultured in Dulbecco's modified eagle medium with 10% fetal bovine serum, 1X antibiotic, basic fibroblast growth factor, and glial cell line-derived neurotrophic factor. The cells were treated with the CM from AD-MSCs for 12 days and then the expression level of differentiation-related genes were measured. Also, the expression level of two major spermatogenic markers of DAZL and DDX4 was calculated. Scp3, Dazl, and Prm1 were significantly increased after treatment compared to the control group, whereas no significant difference was observed in Stra8 expression. The immunocytochemistry images showed that DAZL and DDX4 were positive in experimental group comparing with control. Also, western blotting revealed that both DAZL and DDX4 had higher expression in the treated group than the control group, however, no significant difference was observed. In this study, we concluded that the CM obtained from AD-MSCs can be considered as a suitable biological material to induce the differentiation in SSCs.

• Journal of Plant Biotechnology
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• 제33권3호
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• pp.195-207
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• 2006

Stem cells are the primordial, initial cells which usually divide asymmetrically giving rise to on the one hand self-renewals and on the other hand progenitor cells with potential for differentiation. Zygote (fertilized egg), with totipotency, deserves the top-ranking stem cell - he totipotent stem cell (TSC). Both the ICM (inner cell mass) taken from the 6 days-old human blastocyst and ESC (embryonic stem cell) derived from the in vitro cultured ICM have slightly less potency for differentiation than the zygote, and are termed pluripotent stem cells. Stem cells in the tissues and organs of fetus, infant, and adult have highly reduced potency and committed to produce only progenitor cells for particular tissues. These tissue-specific stem cells are called multipotent stem cells. These tissue-specific/committed multipotent stem cells, when placed in altered environment other than their original niche, can yield cells characteristic of the altered environment. These findings are certainly of potential interest from the clinical, therapeutic perspective. The controversial terminology 'somatic stem cell plasticity' coined by the stem cell community seems to have been proved true. Followings are some of the recent knowledges related to the stem cell. Just as the tissues of our body have their own multipotent stem cells, cancerous tumor has undifferentiated cells known as cancer stem cell (CSC). Each time CSC cleaves, it makes two daughter cells with different fate. One is endowed with immortality, the remarkable ability to divide indefinitely, while the other progeny cell divides occasionally but lives forever. In the cancer tumor, CSC is minority being as few as 3-5% of the tumor mass but it is the culprit behind the tumor-malignancy, metastasis, and recurrence of cancer. CSC is like a master print. As long as the original exists, copies can be made and the disease can persist. If the CSC is destroyed, cancer tumor can't grow. In the decades-long cancer therapy, efforts were focused on the reducing of the bulk of cancerous growth. How cancer therapy is changing to destroy the origin of tumor, the CSC. The next generation of treatments should be to recognize and target the root cause of cancerous growth, the CSC, rather than the reducing of the bulk of tumor, Now the strategy is to find a way to identify and isolate the stem cells. The surfaces of normal as well as the cancer stem cells are studded with proteins. In leukaemia stem cell, for example, protein CD 34 is identified. In the new treatment of cancer disease it is needed to look for protein unique to the CSC. Blocking the stem cell's source of nutrients might be another effective strategy. The mystery of sternness of stem cells has begun to be deciphered. ESC can replicate indefinitely and yet retains the potential to turn into any kind of differentiated cells. Polycomb group protein such as Suz 12 repress most of the regulatory genes which, activated, are turned to be developmental genes. These protein molecules keep the ESC in an undifferentiated state. Many of the regulator genes silenced by polycomb proteins are also occupied by such ESC transcription factors as Oct 4, Sox 2, and Nanog. Both polycomb and transcription factor proteins seem to cooperate to keep the ESC in an undifferentiated state, pluripotent, and self-renewable. A normal prion protein (PrP) is found throughout the body from blood to the brain. Prion diseases such as mad cow disease (bovine spongiform encephalopathy) are caused when a normal prion protein misfolds to give rise to PrP$^{SC}$ and assault brain tissue. Why has human body kept such a deadly and enigmatic protein? Although our body has preserved the prion protein, prion diseases are of rare occurrence. Deadly prion diseases have been intensively studied, but normal prion problems are not. Very few facts on the benefit of prion proteins have been known so far. It was found that PrP was hugely expressed on the stem cell surface of bone marrow and on the cells of neural progenitor, PrP seems to have some function in cell maturation and facilitate the division of stem cells and their self-renewal. PrP also might help guide the decision of neural progenitor cell to become a neuron.

• 생명과학회지
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• 제32권6호
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• pp.468-475
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• 2022

줄기세포와 전구세포 사이의 기능 분석은 여러 조직 특히 혈액에서 잘 확립되어 있다. 특히 조혈줄기세포는 골수 니쉬에서 자가재생능 및 재구성능을 가지고 있으며, 골수 내 기질세포는 조직 기능 조절에 큰 영향을 미친다. 최근 연구에서는 포유동물 줄기세포의 기능은 니쉬 세포 내에서 실험적으로 처음 증명되었고, 특히 미세환경에 의해 종양발생이 가능하다는 증거를 나타내고 있다. 고대에서부터 뼈와 피의 관계는 생체 내 필수불가결인 관계로 진화 과정을 거쳐 포유류의 줄기세포에 대해 최초로 제안되었고, 실험적으로 증명된 니쉬세포를 포함한 미세환경과의 복잡한 상호 관계를 규명하였다. 여러 골수 기질세포는 조혈줄기세포의 기능 조절을 하며, 일부의 기능장애는 골수 이형성 및 백혈병을 유발할 수 있다. 현재까지 여러 기질세포에 대한 맵핑이 되지 않아 현재 많은 연구자들이 단일 분자 수준에서 개개의 기질세포 유형을 파악하는 데이터가 필요하다고 주장하고 있으며 이를 바탕으로 골수 내 조혈줄기세포의 특정 기능을 파악할 수 있다고 볼 수 있다. 따라서 본 총설을 통해 조혈줄기세포 및 미세환경에 대한 이전 연구들의 흥미로운 문제를 논의하고, 조혈줄기세포와 골수 니쉬에 대한 현재 및 새로운 개념을 요약하고자 한다.

• 식물조직배양학회지
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• 제27권6호
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• pp.423-428
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• 2000

In 1997 when cloned sheep Dolly and soon after Polly were born, it had become head-line news because in the former the nucleus that gave rise to the lamb came from cells of six-year-old adult sheep and in the latter case a foreign gene was inserted into the donor nucleus to make the cloned sheep produce human protein, factor IX, in e milk. In the last few years, once the realm of science fiction, cloned mammals especially in livestock have become almost commonplace. What the press accounts often fail to convey, however, is that behind every success lie hundreds of failures. Many of the nuclear-transferred egg cells fail to undergo normal cell divisions. Even when an embryo does successfully implant in the womb, pregnancy often ends in miscarriage. A significant fraction of the animals that are born die shortly after birth and some of those that survived have serious developmental abnormalities. Efficiency remains at less than one % out of some hundred attempts to clone an animal. These facts show that something is fundamentally wrong and enormous hurdles must be overcome before cloning becomes practical. Cloning researchers now tent to put aside their effort to create live animals in order to probe the fundamental questions on cell biology including stem cells, the questions of whether the hereditary material in the nucleus of each cell remains intact throughout development, and how transferred nucleus is reprogrammed exactly like the zygotic nucleus. Stem cells are defined as those cells which can divide to produce a daughter cell like themselves (self-renewal) as well as a daughter cell that will give rise to specific differentiated cells (cell-differentiation). Multicellular organisms are formed from a single totipotent stem cell commonly called fertilized egg or zygote. As this cell and its progeny undergo cell divisions the potency of the stem cells in each tissue and organ become gradually restricted in the order of totipotent, pluripotent, and multipotent. The differentiation potential of multipotent stem cells in each tissue has been thought to be limited to cell lineages present in the organ from which they were derived. Recent studies, however, revealed that multipotent stem cells derived from adult tissues have much wider differentiation potential than was previously thought. These cells can differentiate into developmentally unrelated cell types, such as nerve stem cell into blood cells or muscle stem cell into brain cells. Neural stem cells isolated from the adult forebrain were recently shown to be capable of repopulating the hematopoietic system and produce blood cells in irradiated condition. In plants although the term$\boxDr$ stem cell$\boxUl$is not used, some cells in the second layer of tunica at the apical meristem of shoot, some nucellar cells surrounding the embryo sac, and initial cells of adventive buds are considered to be equivalent to the totipotent stem cells of mammals. The telomere ends of linear eukaryotic chromosomes cannot be replicated because the RNA primer at the end of a completed lagging strand cannot be replaced with DNA, causing 5' end gap. A chromosome would be shortened by the length of RNA primer with every cycle of DNA replication and cell division. Essential genes located near the ends of chromosomes would inevitably be deleted by end-shortening, thereby killing the descendants of the original cells. Telomeric DNA has an unusual sequence consisting of up to 1,000 or more tandem repeat of a simple sequence. For example, chromosome of mammal including human has the repeating telomeric sequence of TTAGGG and that of higher plant is TTTAGGG. This non-genic tandem repeat prevents the death of cell despite the continued shortening of chromosome length. In contrast with the somatic cells germ line cells have the mechanism to fill-up the 5' end gap of telomere, thus maintaining the original length of chromosome. Cem line cells exhibit active enzyme telomerase which functions to maintain the stable length of telomere. Some of the cloned animals are reported prematurely getting old. It has to be ascertained whether the multipotent stem cells in the tissues of adult mammals have the original telomeres or shortened telomeres.