Effects of epigallocatechin gallate on CoCl_(2)-induced apoptosis in PC12 cells

Yang, Kyu-Ho,Mo, Hyun-Chul,Choi, Nam-Ki,Kim, Seon-Mi,Kim,Won-Jae 大韓小兒齒科學會 2006 大韓小兒齒科學會誌 Vol.33 No.1

Neuronal apoptotic events, consequently resulting in neuronal cell death, are occurred in hypoxic/ischemic condition. This cell death has been shown to be accompanied with the production of reactive oxygen species (ROS), which can attack cellular components such as nucleic acids, proteins and phospholipid. However, the underlying mechanisms of apoptosis induced in hypoxic/ischemic condition and its treatment methods are unsettled. Cobalt chloride (CoCl_(2)) has been known to mimic hypoxic condition including the production of ROS. Epigallocatechin gallate (EGCG). a green tea polyphenol, has diverse pharmacologial activities in cell growth and death. This study was aimed to investigate the apoptotic mechanism by CoCl_(2) and effects of EGCG on CoCl_(2)-induced apoptosis in PC12 cells. Administration of CoCl_(2) decreased cell survival in dose- and time-dependent manners and induced genomic DNA fragmentation. Treatment with 100 µM EGCG for 30 min before PC12 cells were exposed to 150 µM CoCl_(2), being resulted in the cell viability and DNA fragmentation being rescued. CoCl_(2) caused morphologic changes such as cell swelling and condensed nuclei, whereas EGCG attenuated morphologic changes by CoCl_(2). EGCG suppressed the apoptotic peak and a loss of Δψ_(m) induced by CoCl_(2). CoCl_(2) decreased Bcl-2 expression but Bax expression was not changed in CoCl_(2)-treated cells. EGCG attenuated the Bcl-2 underexpression by CoCl_(2). CoCl_(2) augumented the cytochrome c release from mitochondria into cytoplasm and increased caspase-8, -9 and caspase-3 activity, a marker of the apoptotic executing stage. EGCG ameliorated the incruement in caspase-8, -9 and -3 activity, and cytochrome c release by CoCl_(2). NAC (N-acetyl-cysteine), a scavenger of ROS, attenuated CoCl_(2)-induced apoptosis in consistent with those of EGCG. These results suggest, that CoCl_(2) induces apoptotic cell death through both mitochondria- and death receptor-dependent pathway and EGCG has neuroprotective effects against CoCl_(2)-induced apoptosis in PC12 cells. 신경세포자멸사는 저산소 및 허혈환경에서 일어나며 이러한 세포죽은 reactive oxidant species (ROS) 생성을 동반함이 알려져있다. 그러나, 저산소 및 허혈환경에서 일어나는 세포자멸사의 기전 및 그 치료방법은 아직 정립되어 있지 않다. CoCl_(2)는 ROS를 생성하는 등 저산소환경과 유사한 조건을 초래하는 것으로 알려져 있다. Epigallocatechin gallate (EGCG)는 녹차의 polyphenol 성분으로서 세포성장과 죽음에 다양한 약리학적 효과를 나타냄이 알려져 있다. 본 연구는 PC12 세포에서 CoCl_(2)에 의한 세포자멸사기전을 밝히고 이에 미치는 EGCG의 효과를 조사하는데 목적이 있다. Cell viability는 MTT 측정으로 조사되었고, DNA fragmentation은 DNA laddering으로 조사되었다. Bcl-2와 Bax발현 정도는 RT-PCR로, caspase-3와 -9의 활성은 spectrophotometer, caspase-8의 활성은 flow cytometry에 의해 측정되었다. 미토콘드리아에서 세포질로 분비된 cytochrome c는 western blot으로, 분해된 DNA 양과 미토콘드리아 세포막전위 (Δψ_(m))는 FACScan으로 조사되었다. CoCl_(2)투여로 PC12 세포수는 용량 및 시간 의존형태로 감소하였고, genomic DNA fragmentation이 발생하였다. CoCl_(2)투여로 야기된 cell viability의 감소와 DNA fragmentation은 EGCG 전처치에 의해 억제되었다. CoCl_(2)은 세포용적팽창과 condensed nuclei 같은 형태적 변화를 일으켰으며, apoptotic peak, Δψ_(m)감소 및 cytochrome c 유리를 야기하였다. EGCG는 CoCl_(2)에 의한 세포형태변화, apoptotic peak, Δψ_(m)소실 및 cytochrome c 유리를 억제시켰다. CoCl_(2)는 Bcl-2 발현을 감소시켰지만, Bax 발현에는 영향을 미치지 않았다. EGCG는 CoCl_(2)에 의해 야기된 Bcl-2 발현 감소를 억제시켰다. CoCl_(2)는 caspase-3, -8, 그리고 -9의 활성을 증가시켰으며, EGCG는 CoCl_(2)에 의한 세포자멸사를 억제시켰다. 본 실험결과는 PC12 세포에서 CoCl_(2)가 미토콘드리아 의존 및 death receptor의존 기전으로 세포자멸사를 일으키며, EGCG는 세포자멸사기전을 억세지킴으로 신경보호기능을 가짐을 시사하였다.

키넥트 센서를 이용한 고령자 대상의 선자세 균형능력 평가

양승태(Seung-Tae Yang),강동원(Dong-Won Kang),서정우(Jeong-Woo Seo),김대혁(Dae-Hyeok Kim),김태호(Tae-Ho Kim),최진승(Jin-Seung Choi),탁계래(Gye-Rae Tack) 대한전기학회 2017 전기학회논문지 Vol.66 No.2

Portable low-cost Kinect sensor was used to analyze standing balance ability of the elderly. Eighty subjects who can walk alone and have a normal cognitive level participated in this experiment. Based on Berg Balance scale (BBS) test with 52 points, subjects were divided into Healthy older (HO: 46 persons, BBS: 53.80 ± 1.19) and Impaired older (IO: 34 persons, BBS: 49.06 ± 2.03) group. Each subject performed 30 seconds four different standing balance tests (EO: Eyes Open, EC: Eyes Close, EOf: Eyes Open on foam, ECf: Eyes Close on foam). Five variables (Mean distance, Range of distance, Root mean square, Mean velocity, 95% ellipse area) were calculated from the hip joint center movement of Kinect sensor. Results showed that there were significant differences between groups for four different standing tests. Calculated variables from kinect sensor showed significant correlation with BBS score. Especially, mediolateral mean distance, mediolateral root mean square, mediolateral range of distance and 95% ellipse area showed discriminative ability for all tests. Mean values of variables of IO were higher than those of HO, which means the decreased balance ability in IO compared with HO. Therefore, it was possible to estimate simple balance assessment of the elderly using portable low-cost Kinect sensor.

Predictable factors of histologic discrepancy of gastric tumor between the endoscopic forceps biopsy and endoscopic treatment specimen

( Ho Kim ),( Sung Hoon Kim ),( Won Hyeong Park ),( Ji Sun Jang ),( Jei So Bang ),( Soo Hyun Yang ),( Jong Hoon Byun ),( Yoon Jung Kim ) 대한내과학회 2011 대한내과학회 추계학술대회 Vol.2011 No.-

PDK1 activity is further regulated by Src through Hsp90

Yang, Keum-Jin,Shin, Sanghee,Piao, Longzhen,Shin, Eulsoon,Li, Yuwen,Park, Kyung Ah,Byun, Hee Sun,Won, M.H.,Kim, Young-Rae,Lee, Hyunji,Hur, Gangmin,Seok, Jeong Ho,A Hemmings, Brian,Park, Jongsun 충남대학교 형질전환복제돼지연구센터 2007 논문집 Vol. No.10

Fabrication of Nanometer-scale Pillar Structures by Using Nanosphere Lithography

Yang, Ji Won,Sim, Jae In,An, Ho Myoung,Kim, Tae Geun Korean Physical Society 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.4

Original Article : Microscopic Characteristics of Lower Eyelid Retractors in Koreans

( Won Kyung Cho ),( Ji Sun Paik ),( Seung Ho Han ),( Suk Woo Yang ) 대한안과학회 2011 Korean Journal of Ophthalmology Vol.25 No.5

Purpose: To identify the microscopic characteristics of lower eyelid retractors in Korean individuals and to elucidate age-related changes in lower eyelid retractors. Methods: Eighteen Korean lower eyelids from formalin-fixed cadavers were stained with Masson`s trichrome. Specimens were divided into two groups based on age at death (group A, ≤65 years; group B, >65 years), and the microscopic findings were analyzed and compared by light microscopy. Results: The capsulopalpebral fascia (CPF) had distinct junctions and no fusion with orbital septum in 14 eyelids (77.8%). The CPF was fused with the orbital septum in only two eyelids (11.1%). Although not significant, the inferior tarsal muscle was closer to the tarsus in group A (1.24 ± 0.71 mm) than group B (2.14 ± 1.18 mm, p = 0.07), and the tarsal height tended to be longer in group B (4.71 ± 0.55 mm) than group A (4.16 ± 1.01 mm, p = 0.20). Tarsal fatty infiltration was more evident in group B. Conclusions: The CPF was rarely fused with the orbital septum in our sample of Korean lower eyelids. Although we did not identify any remarkable age-related changes in lower eyelid structures, there was a tendency for the lower retractor to loosen from the tarsus and for increased fatty infiltration in the lower eyelids from elderly individuals.

MMT and TIMP production in periodontal ligament fibroblasts stimulated by Prevotella nigrescens lipopolysaccharide

Yang, Won-Kyung,Lee, Woo Cheol,Kim, Mi-Ri,Son, Ho-Hyun 大韓齒科保存學會 2005 Restorative Dentistry & Endodontics Vol.30 No.5

이 연구에서는 Prevotella nigrescens (P. nigrescens)의 lipoplysaccharide (LPS)로 자극한 치주인대 섬유아세포에서 matrix metalloproteinase (MMP)와 tissue inhibitor of metalloproteinase (TIMP)의 생성 양상과, LPS를 수산화칼슘으로 처리했을 때의 영향을 평가하였다. P. nigrescens에서 추출, 정제한 여러 농도의 LPS의 수산화칼슘으로 처리한 LPS로 치주인대 섬유아세포를 자극하여, Immunoprecipitation법으로 MMP-1, -2, TIMP-1의 단백질 생성 양상을, real-time polymerase chain reaction법으로 MMP-1의 mRNA 발현 양상을 분석하였다. 이 연구의 결과는 아래와 같다. 1. MMP-1은 단백질과 유전자 수준 모두 자극 시간과 비례하여 증가하여 48시간에 최대값을 보였다. 2. MMP-2 단백질 생성은 1, 10㎎/㎖에서 자극 시간과 비례하여 증가하였다. 3. TIMP-1 단백질 생성은 24시간까지 증가하다가 48시간에 감소하였고, 0.1과 1 ㎍/㎖에서 증가하였으나 10㎍/㎖에서 억제되었다. 4. P.nigrescens의 LPS를 수산화칼슘으로 처리시 MMP-1의 mRNA 발현은 현저하게 감소하였다. The purpose of this study was to monitor the secretion of matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) by human periedontal ligament (PDL) fibroblasts stimulated with Prevotella nigrescens lipopolysaccharide (LPS), and to examine the effect of calcium hydroxide treatment on P. nigrescens LPS. LPS was extracted and purifled from anaerobically cultured P. nigrescens. PDL fibroblasts were stimulated by the LPS (0, 0.1, 1, 10 ㎍/㎖) or LPS (10 ㎍/㎖) preetreated with 12.5 ㎎/㎖ of Ca (OH)_(2) for 3 days, for various periods of time (12, 24, 48 h). Immunoprecipitation were pelformed for protein level analysis of MMP-1, MMP-2 and TIMP-1. Total RNA was isolated and real-time quantitativre polymerase chain reaction (PCR) was performed for quantification of MMP-1 mRNA. According to this study, the results were as follows: 1. The production of MMP-1 by stimulation with P. nigrescens LPS increased in time-dependent manner. and showed maximum value at 48 h in both prootein and mRNA level. But there was no dose-depen-dent increase. 2. MMP-2 production time-dependently increased when stimulated with 1 and 10 ㎍/㎖ LPS, but there was no dose-dependent increase. 3. TIMP-1 production increased to 24 h, but decreased at 48 h. It increased when stimulated with 0.1 and 1㎍/㎖ LPS, but suppressed at 10 ㎍/㎖. 4. P. nigrescens LPS pretreated with Ca (OH)_(2) markedly downregulated MMP-1 gene expression.

Regulation of 3-phosphoinositide-dependent protein kinase-1 (PDK1) by Src involves tyrosine phosphorylation of PDK1 and Src homology 2 domain binding.

Yang, Keum-Jin,Shin, Sanghee,Piao, Longzhen,Shin, Eulsoon,Li, Yuwen,Park, Kyeong Ah,Byun, Hee Sun,Won, Minho,Hong, Janghee,Kweon, Gi Ryang,Hur, Gang Min,Seok, Jeong Ho,Chun, Taehoon,Brazil, Derek P,He American Society for Biochemistry and Molecular Bi 2008 The Journal of biological chemistry Vol.283 No.3

<P>3-Phosphoinositide-dependent protein kinase-1 (PDK1) appears to play a central regulatory role in many cell signalings between phosphoinositide-3 kinase and various intracellular serine/threonine kinases. In resting cells, PDK1 is known to be constitutively active and is further activated by tyrosine phosphorylation (Tyr(9) and Tyr(373/376)) following the treatment of the cell with insulin or pervanadate. However, little is known about the mechanisms for this additional activation of PDK1. Here, we report that the SH2 domain of Src, Crk, and GAP recognized tyrosine-phosphorylated PDK1 in vitro. Destabilization of PDK1 induced by geldanamycin (a Hsp90 inhibitor) was partially blocked in HEK 293 cells expressing PDK1-Y9F. Co-expression of Hsp90 enhanced PDK1-Src complex formation and led to further increased PDK1 activity toward PKB and SGK. Immunohistochemical analysis with anti-phospho-Tyr(9) antibodies showed that the level of Tyr(9) phosphorylation was markedly increased in tumor samples compared with normal. Taken together, these data suggest that phosphorylation of PDK1 on Tyr(9), distinct from Tyr(373/376), is important for PDK1/Src complex formation, leading to PDK1 activation. Furthermore, Tyr(9) phosphorylation is critical for the stabilization of both PDK1 and the PDK1/Src complex via Hsp90-mediated protection of PDK1 degradation.</P>

Hyaluronic acid–tumor necrosis factor-related apoptosis-inducing ligand conjugate for targeted treatment of liver fibrosis

Yang, Jeong-A,Kong, Won Ho,Sung, Dong Kyung,Kim, Hyemin,Kim, Tae Hyung,Lee, Kang Choon,Hahn, Sei Kwang Elsevier 2015 ACTA BIOMATERIALIA Vol.12 No.-

<P><B>Abstract</B></P> <P>Liver fibrosis is a chronic liver disease caused by viral infection and/or metabolic, genetic and cholestatic disorders. The inhibition of hepatic stellate cell (HSC) activation and the selective apoptosis of activated HSCs can be a good strategy to treat liver fibrosis. The activated HSCs are known to be more susceptible to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induced apoptosis than normal HSCs because death receptor 5 is overexpressed on the cell surface. In this work, a target-specific and long-acting hyaluronic acid (HA)–TRAIL conjugate was successfully developed for the treatment of liver fibrosis. The HA–TRAIL conjugate was synthesized by a coupling reaction between aldehyde-modified HA and the N-terminal amine group of TRAIL. The biological activity of the HA–TRAIL conjugate was confirmed by an in vitro anti-proliferation assay and caspase-3 expression in human colon cancer HCT116 cells. In vivo real-time bioimaging exhibited the target-specific delivery of near-infrared fluorescence dye-labeled HA–TRAIL conjugate to the liver in mice. According to pharmacokinetic analysis, the HA–TRAIL conjugate was detected for more than 4days after single intravenous injection into Sprague–Dawley (SD) rats. Finally, we could confirm the antifibrotic effect of HA–TRAIL conjugate in an <I>N</I>-nitrosodimethylamine-induced liver fibrosis model SD rats.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Modification of conventional X-ray diffractometer for the measurement of phase distribution in a narrow region

Yang-Soon Park,Sun-Ho Han,Jong-Goo Kim,Kwang-Yong Jee,Won-Ho Kim 한국분석과학회 2006 분석과학 Vol.19 No.5