Prostaglandin A₂-induced Apoptosis is Not Inhibited by Heme Oygenase-1 in U2OS Cells

Kyoung-Won Ko(고경원),Sun-Young Lee(이선영),Ji-Hyun Ahn(안지현),Jaetaek Kim(김재택),In-Kyung Kim(김인경),Ho-Shik Kim(김호식) 한국생명과학회 2008 생명과학회지 Vol.18 No.11

Prostaglandin A₂ (PGA₂)는 사람 골육종 세포인 U2OS 세포주에서 apoptosis와 heme oxygenase (HO)-1의 발현을 함께 유도하였다. PGA₂에 의한 apoptosis는 HO-1의 과도한 발현이나 HO-1에 대한 small interfering RNA에 의한 발현저하에 의하여 변동되지 않았으나 H₂O₂에 의한 세포사망은 HO-1의 발현 수준에 반비례하여 변동되었다. 또한 thiol antioxidant인 N-acetyl-L-cysteine (NAC)은 PGA₂에 의한 세포사망과 HO-1의 발현 증가를 모두 차단하였지만, non-thiol antioxidant인 butylated hydroxyanisole (BHA)과 ascorbic acid는 세포사망과 HO-1의 발현 유도를 차단하지 않았다. 이와 같은 결과들은 PGA₂는 산화성 손상에 의해서가 아니라 PGA₂의 thiol-reactivity에 의하여 apoptosis와 HO-1의 발현을 유도하며, HO-1의 발현은 PGA₂에 의한 apoptosis와는 독립적인 현상이거나 기능적으로 apoptosis 유도의 하부에 위치하고 apoptosis의 진행에는 기여하지 않을 것이라는 것을 시사해 준다. Prostaglandin A₂ (PGA₂), one of cyclopentenone PGs, induced both apoptosis and heme oxygenase (HO)-1 expression in U2OS cells. PGA₂-induced apoptosis was not perturbed by either over-expression or knock-down of HO-1, whereas H₂O₂-induced cell death was inversely modulated by the expression level of HO-1. In addition, N-acetyl-L-cysteine (NAC), a thiol antioxidant, blocked both apoptosis and HO-1 expression induced by PGA₂. But, non-thiol antioxidants like butylated hydorxyanisole (BHA) and ascorbic acid did not block either apoptosis or HO-1-induction. Taken together, these results suggest that PGA₂ induces both apoptosis and HO-1 expression, which are critically related to the thiol-reactivity of PGA₂, but not oxidative stress, and HO-1 expression may be independent or functionally located downstream of apoptosis by PGA₂ without contribution to apoptosis progression.

Nutlin-3 induces HO-1 expression by activating JNK in a transcription-independent manner of p53

CHOE, YUN-JEONG,LEE, SUN-YOUNG,KO, KYUNG WON,SHIN, SEOK JOON,KIM, HO-SHIK Spandidos Publications 2014 International journal of oncology Vol.44 No.3

A recent study reported that p53 can induce HO-1 by directly binding to the putative p53 responsive element in the HO-1 promoter. In this study, we report that nutlin-3, a small molecule antagonist of HDM2, induces the transcription of HO-1 in a transcription-independent manner of p53. Nutlin-3 induced HO-1 expression at the level of transcription in human cancer cells such as U2OS and RKO cells. This induction of HO-1 did not occur in SAOS cells in which p53 was mutated and was prevented by knocking down the p53 protein using p53 siRNA transfection, but not by PFT-alpha, an inhibitor of the transcriptional activity of p53. Accompanying HO-1 expression, nutlin-3 stimulated the accumulation of ROS and the phosphorylation of MAPKs such as JNK, p38 MAPK and ERK1/2. Nutlin-3-induced HO-1 expression was suppressed by TEMPO, a ROS scavenger, and chemical inhibitors of JNK and p38 MAPK but not ERK1/2. In addition, nutlin-3-induced phosphorylation of JNK but not p38 MAPK was inhibited by TEMPO. Notably, the levels of nutlin-3-induced ROS were correlated with the mitochondrial translocation of p53 and this induction was prevented by PFT-beta, an inhibitor of the mitochondrial translocation of p53. Consistent with the effect of the ROS scavenger and MAPK inhibitors, PFT-beta reduced HO-1 expression and the phosphorylation of JNK induced by nutlin-3. In the experiments of analyzing cell death, the knockdown of HO-1 augmented nutlin-3-induced apoptosis. Collectively, these results suggest that nutlin-3 induces HO-1 expression via the activation of both JNK which is dependent on ROS generated by p53 translocated to the mitochondria and p38 MAPK which appears to be stimulated by a ROS-independent mechanism, and this HO-1 induction may inhibit nutlin-3-induced apoptosis, constituting a negative feedback loop of p53-induced apoptosis.

PGA2-induced expression of HO-1 is mediated by transcriptional upregulation of Nrf2

Sang-sun Lee,Yun-Jeong Choe,Hyein Lee,Sun-Young Lee,Ho-Shik Kim 대한독성 유전단백체 학회 2019 Molecular & cellular toxicology Vol.15 No.2

Backgrounds: Prostaglandin (PG) A2 reportedly stimulated expression of heme oxygenase (HO)-1 at the level of transcription via the activation of p38MAPK. Details of the mechanism, however, have not been provided, and this includes identification of the transcription factors responsible for PGA2-induced HO-1 expression. Herein is described an analysis of the role of nuclear factor erythroid 2 related factor 2 (Nrf2) and how PGA2 increases the activity of Nrf2 during PGA2-induced HO-1 expression. Methods: Expressions of HO-1 and Nrf2 were analyzed at the levels of both mRNA and protein. Nrf2 siRNA, SB203580, an inhibitor of p38MAPK, and scavengers of reactive oxygen species (ROS) were used to identify the effects of Nrf2, p38MAPK and ROS on PGA2-induced HO-1 expression. Results: Although SB203580 suppressed PGA2-induced HO-1 expression, genetic activation of p38MAPK could not stimulate the transcription of HO-1. Cycloheximide (CHX), an inhibitor of protein translation, almost completely prevented PGA2-induced increase of HO-1 transcription, but it did not prevent the phosphorylation of p38MAPK, which suggests that both de novo protein synthesis and p38MAPK activity are required to induce the transcription of HO-1 in response to PGA2 treatment. In addition, PGA2 increased the level of both Nrf2 mRNA and protein in a dose-dependent manner. Knockdown of Nrf2 using small interfering RNA (siRNA) suppressed PGA2-induced HO-1 expression. The PGA2-induced transcription of Nrf2 was prevented by ROS scavengers such as n-acetyl-l-cysteine and tempol but not CHX. Furthermore, siRNA against p38MAPK did not change the level of nuclear Nrf2 protein. Conclusion: These findings suggest that PGA2 induces HO-1 transcription via an increase in Nrf2 protein, the transcription of which is initiated by an accumulation of ROS that is independent of the p38MAPK activation pathway.

PGA2 induces the expression of HO-1 by activating p53 in HCT116 cells

Hyein Lee,Sang-Sun Lee,Ji-Young Park,Yun-Jeong Choe,이선영,Ho-Shik Kim,H.-S. Kim 대한독성 유전단백체 학회 2017 Molecular & cellular toxicology Vol.13 No.2

Prostaglandin (PG) A2 which is a cytotoxic PG, was reported to induce the expression of heme oxygenase (HO)-1 via activation of p38MAPK to keep U2OS cells from cell cycle arrest in G2M phase. The expression of HO-1 is primarily regulated at the level of transcription. But the transcription factors that are responsible for PGA2-induced HO-1 expression were not clarified yet. Here, we report that PGA2-induced transcription of HO-1 is mediated by p53, a tumor suppressive transcription factor. In HCT116 cells, PGA2 treatment led to the phosphorylation of p53 and an increase of p21WAF1 transcription as well as the activation of HO-1 transcription. Knocking p53 down via RNA interference or inhibiting the p53’s transcriptional activity by pifithrin-α treatment led to suppression of the increase in the level of both HO-1 expression and activity of HO-1 promoter. Pretreatment of NU- 7441, a chemical inhibitor of DNA-activated protein kinase (DNA-PK), prevented both the PGA2-induced phosphorylation of p53 and an increase of HO-1 transcription. In addition, N-acetyl-l-cysteine, a scavenger of reactive oxygen species (ROS), also mimicked the effect of NU-7441 on the PGA2-induced activation of p53 and HO-1 transcription. Collectively, these results suggest that PGA2 induces the expression of HO-1 via activation of p53, which is mediated by the ROSDNA- PK pathway.

PGA2-induced HO-1 attenuates G2M arrest by modulating GADD45α expression

Yun-Jeong Choe,고경원,Hyein Lee,이선영,Byung-Chul Kim,Ho-Shik Kim,Ho-Shik Kim 대한독성 유전단백체 학회 2015 Molecular & cellular toxicology Vol.11 No.4

Prostaglandin (PG) A2, a cyclopentenone PG, arrested the growth of U2OS cells in the G2M phase. While inducing G2M arrest, PGA2 increased the expression of heme oxygenase-1 (HO-1) at the level of transcription along with the accumulation of ROS and the activation of MAPKs including JNK, p38MAPK, and ERK1/2. Among the MAPKs, the inhibition of p38MAPK by a specific chemical inhibitor SB203580, or by RNA interference, but not JNK or ERK1/2, attenuated the PGA2-induced transcription of HO-1. Nacetylcysteine (NAC), a ROS scavenger, prevented PGA2-induced G2M arrest, p38MAPK activation and transcriptional induction of HO-1. PGA2 also stimulated GADD45α expression at the level of transcription, and the knockdown of GADD45α repressed PGA2- induced G2M arrest. Finally, the knockdown of the HO-1 protein elevated PGA2-induced GADD45α expression as well as G2M arrest. Collectively, these results suggest that PGA2 causes an increase in ROS accumulation which initiates both HO-1 transcription via p38MAPK, and G2M arrest via GADD45α transcription, and HO-1 attenuates G2M arrest by modulating the expression of GADD45α.

Protective Effects of Hyperoside against Carbon Tetrachloride-Induced Liver Damage in Mice

Choi, Jun-Ho,Kim, Dong-Wook,Yun, Nari,Choi, Jae-Sue,Islam, Md. Nurul,Kim, Yeong-Shik,Lee, Sun-Mee American Chemical Society and American Society of 2011 Journal of natural products Vol.74 No.5

<P>In this study, the hepatoprotective effects of hyperoside (<B>1</B>), a flavonoid glycoside isolated from <I>Artemisia capillaris</I>, have been examined against carbon tetrachloride (CCl<SUB>4</SUB>)-induced liver injury. Mice were treated intraperitoneally with vehicle or <B>1</B> (50, 100, and 200 mg·kg<SUP>−1</SUP>) 30 min before and 2 h after CCl<SUB>4</SUB> (20 μL·kg<SUP>−1</SUP>) injection. Levels of serum aminotransferases were increased 24 h after CCl<SUB>4</SUB> injection, and these increases were attenuated by <B>1</B>. Histological analysis showed that <B>1</B> prevented portal inflammation, centrizonal necrosis, and Kupffer cell hyperplasia. Lipid peroxidation was increased and hepatic glutathione content was decreased significantly after CCl<SUB>4</SUB> treatment, and these changes were reduced by administration of <B>1</B>. Protein and mRNA expression of tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and heme oxygenase-1 (HO-1) and nuclear protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2) significantly increased after CCl<SUB>4</SUB> injection. Compound <B>1</B> suppressed TNF-α, iNOS, and COX-2 protein and mRNA expression and augmented HO-1 protein and mRNA expression and Nrf2 nuclear protein expression. These results suggest that <B>1</B> has protective effects against CCl<SUB>4</SUB>-induced acute liver injury, and this protection is likely due to enhancement of the antioxidative defense system and suppression of the inflammatory response.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jnprdf/2011/jnprdf.2011.74.issue-5/np200001x/production/images/medium/np-2011-00001x_0006.gif'></P>

Protective Effect of Baicalin Against Carbon Tetrachloride–Induced Acute Hepatic Injury in Mice

Park, Sang-Won,Lee, Chan-Ho,Kim, Yeong Shik,Kang, Sam Sik,Jeon, Su Jin,Son, Kun Ho,Lee, Sun-Mee The Japanese Pharmacological Society 2008 JOURNAL OF PHARMACOLOGICAL SCIENCES Vol.106 No.1

<P>This study examined the effects of baicalin, a bioactive flavonoid isolated from <I>Scutellariae Radix</I>, on carbon tetrachloride (CCl<SUB>4</SUB>)-induced liver injury. Mice were treated intraperitoneally with 0.5 ml/kg CCl<SUB>4</SUB> and different groups of animals received 25, 50, 100, and 200 mg/kg baicalin. At 24 h after the CCl<SUB>4</SUB> treatment, the level of serum aminotransferases and lipid peroxidation was significantly elevated, whereas the hepatic glutathione content was decreased. These changes were attenuated by baicalin. The histological studies showed that baicalin inhibited the portal inflammation, centrizonal necrosis, and Kupffer cell hyperplasia, which are the three most common characteristics of CCl<SUB>4</SUB>-induced liver damage. The serum level and mRNA expression of tumor necrosis factor-α were markedly increased by the CCl<SUB>4</SUB> treatment but suppressed by baicalin. The mRNA and protein expression levels of inducible nitric oxide synthase and heme oxygenase-1 increased significantly at 24 h after the CCl<SUB>4</SUB> treatment. Baicalin attenuated the increase in the protein and gene expression of inducible nitric oxide synthase but augmented the increase in those of heme oxygenase-1. These findings suggest that baicalin protects hepatocytes from the oxidative damage caused by CCl<SUB>4</SUB>, and this protection is likely due to the induction of HO-1 expression and the inhibition of the proinflammatory mediators.</P>

골수이식 후 골밀도 및 골대사의 변화 : 2년 추적관찰 2-Year Prospective Study

이원영,강무일,오은숙,오기원,한제호,손현식,윤건호,차봉연,이광우,손호영,강성구,신완식,민우성,김춘추 대한내분비학회 2000 Endocrinology and metabolism Vol.15 No.4·5

Conformational Studies of Macrocyclic Corrin-Ring of Coenzyme B_(12) by NMR Methods

원호식 한양대학교 이학기술연구소 1999 이학기술연구지 Vol.1 No.-

Cobalamine의 구조적인 변형은 B_(12)의존 효소들에 의한 Cl 촉매회로의 첫 번째 과정에서 Co-C 결합의 균일 분해에 중요하다고 생각되어진다. Corrin 고리의 구조를 결정하기 위하여 2D-NMR실험을 시행하였다. 동핵관련 및 이핵관련 NMR 실험을 이용하여 ^(1)h-NMR 신호를 지정하였다. NOE비 대각항의 신호세기로부터 얻어진 다양한 H 쌍들의 거리정보를 얻었고 3차원구조 결정을 위하여 Distance Geometry(DG)에서 사용하였다. 얻어진 NMR 3차원구조는 X-ray 결정구조에서 얻은 구조와 비교하였다. 거대고리인 Corin과 4개의 Pyrrole고리보다는 Benzimidazole기와 Sugar 고리에서 더 큰 구조적인 차이점을 보였다. 본 연구에 사용된 DG방법이 분자의 tumbling 시간이 특이하여 ωπ_(c)가 1.0근접하기 때문에 NOE 효과가 약하게 나타나는 분자들에 대하여 NMR 을 근거로 한 구조결정에도 적절하게 응용할 수 있었다. An enzyme derived conformational changes of cobalamine is thought to be important in the homolytic cleavage of Co-C bond which is the first step of catalytic Cl-cycle of coenzyme B_(12)-dependent enzymes. Modern 2D-NMR and NMR-basee distance geometric studies were carried out to determine the 3D structure of corrin ring. Homonuclear and heteronuclear correlation NMR experiments were made for complete ^(1)h-NMR signal assignments. Distance of numerous proton pairs were obtained based on the NOE cross peak intensities and subsequently assigned to the distance geometry program for the 3D structure determination. The detailed 3D structure from current NMR-based structure were compared with the results from X-ray crystallographic structure. As a results, conformational changes of benzimidazole group and sugar ring were greater than that of macrocyclic corrin and tetrapyrrole. In addition, the distance geometry used in this study was quite useful in NMR-based structure determination of medium sized molecules that give poor NOE effects arsing from ωπ_(c)=1.0 with specific tumbling time.

비젼 제어시스템에 사용된 카메라의 최적개수에 대한 실험적 연구

장완식,김선호,김기영,임호진,안힘찬 朝鮮大學校 機械技術硏究所 2002 機械技術硏究 Vol.5 No.2

The vision system model used for this study involves the six parameters that permits a kinds of adaptability in the relationship between the camera space location of manipulable visual cues and the vector of robot joint coordinates is estimated in real time. Also this vision control method requires the number of cameras to transform 2-D camera plane from 3-D physical space, and be used irrespective of location of cameras, if visual cues are displayed in the same camera plane. Thus, this study is to investigate the optimal number of cameras used for the developed vision control system according to the change of the number of cameras. This study is processed in the two ways : a) effectiveness of vision system model b) optimal number of cameras c) These results show the evidence of the adaptability of the developed vision control method using the optimal number of cameras.