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Lee, Hye Jeong,Choi, Na Young,Park, Yo Seph,Lee, Seung-Won,Bang, Jin Seok,Lee, Yukyeong,Ryu, Jae-Sung,Choi, Seong-Jin,Lee, Sang-Hyub,Kim, Gwang Soo,Chung, Hyun Woo,Ko, Kisung,Lee, Kyuhong,Ko, Kinarm Elsevier 2018 Reproductive toxicology Vol.78 No.-
<P><B>Abstract</B></P> <P>Animal models and human studies showed that <I>in utero</I> cigarette smoke exposure decreases sperm counts of offspring. This study used a mouse model to investigate the effects of maternal exposure to cigarette smoke on reproductive systems in F1 and F2 male offspring. Female ICR mice were exposed either to clean air or to cigarette smoke during pregnancy at the post-implantation stage. Epididymal sperm counts were decreased in a cigarette smoke dose–dependent manner in F1 (by 40–60%) and F2 males (by 23–40%) at postnatal day 56. In F1, the seminiferous epithelium heights were lower in the cigarette smoke–exposed groups than in the control group, and these effects were sustained in F2 males. Results suggest that maternal cigarette smoke exposure during pregnancy can have a multigenerational adverse effect on sperm counts in male offspring, which is mediated through <I>in utero</I> exposure of fetal germ cells to cigarette smoke.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Maternal cigarette smoke exposure caused low sperm counts of male offspring. </LI> <LI> Seminiferous epithelium heights of male offspring were decreased in the exposed groups. </LI> <LI> Maternal cigarette smoke exposure has a multigenerational adverse effect. </LI> </UL> </P>
Lee, Seung-Won,Wu, Guangming,Choi, Na Young,Lee, Hye Jeong,Bang, Jin Seok,Lee, Yukyeong,Lee, Minseong,Ko, Kisung,Scholer, Hans R.,Ko, Kinarm Korean Society for Molecular and Cellular Biology 2018 Molecules and cells Vol.41 No.7
Spermatogonial stem cells (SSCs) derived from mouse testis are unipotent in regard of spermatogenesis. Our previous study demonstrated that SSCs can be fully reprogrammed into pluripotent stem cells, so called germline-derived pluripotent stem cells (gPS cells), on feeder cells (mouse embryonic fibroblasts), which supports SSC proliferation and induction of pluripotency. Because of an uncontrollable microenvironment caused by interactions with feeder cells, feeder-based SSC reprogramming is not suitable for elucidation of the self-reprogramming mechanism by which SSCs are converted into pluripotent stem cells. Recently, we have established a Matrigel-based SSC expansion culture system that allows longterm SSC proliferation without mouse embryonic fibroblast support. In this study, we developed a new feeder-free SSC self-reprogramming protocol based on the Matrigel-based culture system. The gPS cells generated using a feeder-free reprogramming system showed pluripotency at the molecular and cellular levels. The differentiation potential of gPS cells was confirmed in vitro and in vivo. Our study shows for the first time that the induction of SSC pluripotency can be achieved without feeder cells. The newly developed feeder-free self-reprogramming system could be a useful tool to reveal the mechanism by which unipotent cells are self-reprogrammed into pluripotent stem cells.
MinSoo Byun,Dahyun Yi,JunHo Lee,YoungMin Choe,BoKyung Sohn,JunYoung Lee,HyoJung Choi,Hyewon Baek,YuKyeong Kim,YunSang Lee,ChulHo Sohn,Inhee MookJung,Murim Choi,YuJin Lee,DongWoo Lee,SeungHo Ryu,ShinGy 대한신경정신의학회 2017 PSYCHIATRY INVESTIGATION Vol.14 No.6
Objective-The Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer’s disease (KBASE) aimed to recruit 650 individuals, aged from 20 to 90 years, to search for new biomarkers of Alzheimer’s disease (AD) and to investigate how multi-faceted lifetime experiences and bodily changes contribute to the brain changes or brain pathologies related to the AD process. Methods-All participants received comprehensive clinical and neuropsychological evaluations, multi-modal brain imaging, including magnetic resonance imaging, magnetic resonance angiography, [11C]Pittsburgh compound B-positron emission tomography (PET), and [18F]fluorodeoxyglucose-PET, blood and genetic marker analyses at baseline, and a subset of participants underwent actigraph monitoring and completed a sleep diary. Participants are to be followed annually with clinical and neuropsychological assessments, and biannually with the full KBASE assessment, including neuroimaging and laboratory tests. Results-As of March 2017, in total, 758 individuals had volunteered for this study. Among them, in total, 591 participants-291 cognitively normal (CN) old-aged individuals, 74 CN young- and middle-aged individuals, 139 individuals with mild cognitive impairment (MCI), and 87 individuals with AD dementia (ADD)-were enrolled at baseline, after excluding 162 individuals. A subset of participants (n=275) underwent actigraph monitoring. Conclusion-The KBASE cohort is a prospective, longitudinal cohort study that recruited participants with a wide age range and a wide distribution of cognitive status (CN, MCI, and ADD) and it has several strengths in its design and methodologies. Details of the recruitment, study methodology, and baseline sample characteristics are described in this paper.
Yukyeong Lee,김은성,Sangeun Park,Jeong Min Park,Jae Bok Seol,Hyoung Seop Kim,이태경,Hyokyung Sung,Jung Gi Kim 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.1
Process optimization of additively manufactured Ti–6Al–4V alloy is an important aspect of the production of engineered,high-performance parts for the aerospace and medical industries. In this study, the microstructural evolution and mechanicalproperties of direct energy deposition processed Ti–6Al–4V alloy were investigated using diferent processing parameters. Experimental analyses revealed that the line energy density corresponding to the processing parameters of the direct energydeposition process infuences the properties of additively manufactured Ti–6Al–4V alloy. First, an optimal line energydensity limits the incidence and size of voids resulting from a lack of fusion to enhance both alloy strength and ductility. Second, an excessively high energy density induces the coarsening of prior-β grains to impair both alloy strength with theHall–Petch relationship and alloy ductility due to the plastic deformation instability caused by the limited number of grains. These results indicate that both the extent of fusion and prior-β grain size afect the mechanical properties of additivelymanufactured Ti–6Al–4V alloy. Moreover, the results demonstrate the utility of the line energy density-based approach indetermining the optimal processing parameters for realizing high-performance materials.
Lee, Yukyeong,Kim, C-Yoon,Lee, Hye Jeong,Kim, Jae Gon,Han, Dong Wook,Ko, Kisung,Walter, James,Chung, Hyung-Min,Schö,ler, Hans R.,Bae, Young Min,Ko, Kinarm Frontiers Media S.A. 2018 Frontiers in cellular neuroscience Vol.12 No.-
<P>Oligodendrocyte progenitor cells (OPCs) are attracting attention as the ideal cell therapy for spinal cord injury (SCI). Recently, advanced reprogramming and differentiation techniques have made it possible to generate therapeutic cells for treating SCI. In the present study, we used directly-induced neural stem cells (DNSCs) from fibroblasts to establish OPCs (DN-OPCs) capable of proliferation and confirmed their OPC-specific characteristics. Also, we evaluated the effect of transplanted DN-OPCs on SCI in rats. The DN-OPCs exhibited an OPC-specific phenotype and electrophysiological function and could be differentiated into oligodendrocytes. In the SCI model, transplanted DN-OPCs improved behavior recovery, and showed engraftment into the host spinal cord with expression of myelin basic protein. These results suggest that DN-OPCs could be a new source of potentially useful cells for treating SCI.</P>
Lee, Hye Jeong,Choi, Na Young,Lee, Seung-Wong,Lee, Yukyeong,Ko, Kisung,Kim, Gwang Jun,Hwang, Han Sung,Ko, Kinarm Korean Society for Stem Cell Research 2019 International journal of stem cells Vol.12 No.1
<P><B>Background and Objectives</B></P><P>Genomic imprinting modulates growth and development in mammals and is associated with genetic disorders. Although uniparental embryonic stem cells have been used to study genomic imprinting, there is an ethical issue associated with the destruction of human embryos. In this study, to investigate the genomic imprinting status in human neurodevelopment, we used human uniparental induced pluripotent stem cells (iPSCs) that possessed only maternal alleles and differentiated into neural cell lineages.</P><P><B>Methods</B></P><P>Human somatic iPSCs (hSiPSCs) and human parthenogenetic iPSCs (hPgiPSCs) were differentiated into neural stem cells (NSCs) and named hSi-NSCs and hPgi-NSCs respectively. DNA methylation and gene expression of imprinted genes related neurodevelopment was analyzed during reprogramming and neural lineage differentiation.</P><P><B>Results</B></P><P>The DNA methylation and expression of imprinted genes were altered or maintained after differentiation into NSCs. The imprinting status in NSCs were maintained after terminal differentiation into neurons and astrocytes. In contrast, gene expression was differentially presented in a cell type-specific manner.</P><P><B>Conclusions</B></P><P>This study suggests that genomic imprinting should be determined in each neural cell type because the genomic imprinting status can differ in a cell type-specific manner. In addition, the <I>in vitro</I> model established in this study would be useful for verifying the epigenetic alteration of imprinted genes which can be differentially changed during neurodevelopment in human and for screening novel imprinted genes related to neurodevelopment. Moreover, the confirmed genomic imprinting status could be used to find out an abnormal genomic imprinting status of imprinted genes related with neurogenetic disorders according to uniparental genotypes.</P>