http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Park, Sung Wook,Kim, Jin Hyoung,Kim, Ko-Eun,Jeong, Moon Hee,Park, Hyunsung,Park, Bongju,Suh, Young-Ger,Park, Woo Jin,Kim, Jeong Hun BlackWell Publishing Ltd 2014 JOURNAL OF CELLULAR AND MOLECULAR MEDICINE Vol.18 No.5
<P>Retinal neovascularization in retinopathy of prematurity (ROP) is the most common cause of blindness for children. Despite evidence that hypoxia inducible factor (HIF)-1α -VEGF axis is associated with the pathogenesis of ROP, the inhibitors of HIF-1α have not been established as a therapeutic target in the control of ROP pathophysiology. We investigated the hypothesis that degradation of HIF-1α as a master regulator of angiogenesis in hypoxic condition, using β-lapachone, would confer protection against hypoxia-induced retinopathy without affecting physiological vascular development in mice with oxygen-induced retinopathy (OIR), an animal model of ROP. The effects of β-lapachone were examined after intraocular injection in mice with OIR. Intraocular administration of β-lapachone resulted in significant reduction in hypoxia-induced retinal neovascularization without retinal toxicity or perturbation of developmental retinal angiogenesis. Our results demonstrate that HIF-1α–mediated VEGF expression in OIR is associated with pathological neovascularization, not physiological angiogenesis. Thus, strategies blocking HIF-1α in the developing eye in the pathological hypoxia could serve as a novel therapeutic target for ROP.</P>
Lim, Wonchung,Park, Yeomyung,Cho, Jungyoon,Park, Choa,Park, Joonwoo,Park, Young-Kwon,Park, Hyunsung,Lee, YoungJoo BioMed Central 2011 Breast cancer research Vol.13 No.2
<P><B>Introduction</B></P><P>Estrogen receptor (ER) β is predicted to play an important role in prevention of breast cancer development and metastasis. We have shown previously that ERβ inhibits hypoxia inducible factor (HIF)-1α mediated transcription, but the mechanism by which ERβ works to exert this effect is not understood.</P><P><B>Methods</B></P><P>Vascular endothelial growth factor (VEGF) was measured in conditioned medium by enzyme-linked immunosorbent assays. Reverse transcription polymerase chain reaction (RT-PCR), Western blotting, immunoprecipitation, luciferase assays and chromatin immunoprecipitation (ChIP) assays were used to ascertain the implication of ERβ on HIF-1 function.</P><P><B>Results</B></P><P>In this study, we found that the inhibition of HIF-1 activity by ERβ expression was correlated with ERβ's ability to degrade aryl hydrocarbon receptor nuclear translocator (ARNT) via ubiquitination processes leading to the reduction of active HIF-1α/ARNT complexes. HIF-1 repression by ERβ was rescued by overexpression of ARNT as examined by hypoxia-responsive element (HRE)-driven luciferase assays. We show further that ERβ attenuated the hypoxic induction of VEGF mRNA by directly decreasing HIF-1α binding to the VEGF gene promoter.</P><P><B>Conclusions</B></P><P>These results show that ERβ suppresses HIF-1α-mediated transcription via ARNT down-regulation, which may account for the tumour suppressive function of ERβ.</P>
Fast Active Appearance Model for Mobile Device
Hyunsung Park(박현성),Jongju Shin(신종주),Jieun Kim(김지은),Daijin Kim(김대진) 한국정보과학회 2014 정보과학회 컴퓨팅의 실제 논문지 Vol.20 No.6
본 논문에서는 휴대 단말기에서 동작하는 고속 Active Appearance Model을 제안한다. 일반적으로 쓰이는 Active Appearance Model fitting 알고리즘과 다르게, 본 논문에서 제안하는 방법은 학습을 통하여 Active Appearance Model fitting의 연산시간을 크게 줄여준다. 일반적인 Active Appearance Model fitting방법은 연산 성능이 낮은 휴대 단말기에 적용할 수 없지만, 제안하는 방식은 연산시간을 획기적으로 줄이면서도 fitting 성능 저하를 보완하는 추가적인 장치로 인해 큰 성능 저하 없이 휴대 단말기에 적용이 가능하다. In this paper, We introduce fast Active Appearance Model (AAM) for mobile device. Different from typical AAM fitting algorithm, our AAM fitting method significantly reduces computation time by using training method. We train relations between changes of AAM parameters and error image. Because of its mass calculation of floating-point number, typical AAM fitting algorithm cannot be applied to low computing power devices. But, we introduce fast AAM fitting algorithm. Fast AAM fitting algorithm significantly reduces computation time with small sacrifice of accuracy of fitting result by using several techniques. Through this method, we can use AAM fitting algorithm on a mobile device.
( Hyunsung Park ) 생화학분자생물학회(구 한국생화학분자생물학회) 2017 BMB Reports Vol.50 No.11
Hypoxia affects various physiological and pathophyological processes. Hypoxia changes the expression of hypoxia-responsive genes through two main pathways. First, hypoxia activates transcription factors (TF) such as Hypoxia-inducible Factor (HIF). Second, hypoxia decreases the activity of Jumonji C domain-containing histone demethylases (JMJDs) that require O<sub>2</sub> and α-Ketoglutarate (α-KG) as substrates. The JMJDs affect gene expression through their regulation of active or repressive histone methylations. Profiling of H3K4me3, H3K9me3, and H3K27me3 under both normoxia and hypoxia identified 75 TFs whose binding motifs were significantly enriched in the methylated regions of the genes. TFs showing similar binding strengths to their target genes might be under the ‘metabolic control’ which changes histone methylation and gene expression by instant changing catalytic activities of resident histone demethylases. [BMB Reports: Perspective 2017; 50(11): 537-538]
Ligand and Dimerization Dependent Transactivation Capability of Aromatic Hydrocarbon Receptor
Park,Hyunsung The Korea Science and Technology Center 1999 BMB Reports Vol.32 No.3
The aromatic hydrocarbon receptor (AhR) is a cytosolic protein that binds the environmental pollutant, dioxin. The liganded AhR translocates into the nucleus protein, AhR nuclear translocator (Arnt). The N-terminal regions of both AhR and Arnt contain basic helix-loop-helix (bHLH) and Per-AhR-Arnt-Sim (PAS) motifs that are required for DNA binding, dimerization, and ligand binding whereas the C-terminal regions of both AhR and Arnt contain transactivation domains. Here, results from the mammmalian two-hybrid system indicate that Arnt canmake a homodimer but AhR cannnot. In the presence of dioxin, the interaction between AhR and Arnt is stronger than that of the Arnt homodimer, suggesting that Arnt prefers to make a heterodimer with the liganded AhR prefers to make a heterodimer with the liganded AhR rather than a homodimer. Transfection analyses using the GAL4-driven reporter system suggest that AhR's N-terminal region represses its own transactivation domain, as well as exogenous transactivation domain, such as Sp1 and VP16. Interestingly, the repressed transaction domains of AhR are activated by ligand-dependent heterodimerization with Arnt. These observations suggest tat heterodimerzation with Arnt is necessary not only for DNA binding but also for activation of the repressed transactivation capability of AhR.
Novel Dioxygenases, HIF-α Specific Prolyl-hydroxylase and Asparanginyl-hydroxylase
Hyunsung Park 한국독성학회 2008 Toxicological Research Vol.24 No.2
Studies on hypoxia-signaling pathways have revealed novel Fe(Ⅱ) and α-ketoglutarate-dependent dioxygenases that hydroxylate prolyl or asparaginyl residues of a transactivator, Hypoxia-Inducible Factor-α (HIF-α) protein. The recognition of these unprecedented dioxygenases has led to open a new paradigm that the hydroxylation mediates an instant post-translational modification of a protein in response to the changes in cellular concentrations of oxygen, reducing agents, or α-ketoglutarate. Activity of HIF-α is repressed by two hydroxylases. One is HIF-α specific prolyl-hydroxylases, referred as prolyl-hydroxylase domain (PHD). The other is HIF-α specific asparaginyl-hydroxylase, referred as factor-inhibiting HIF-1 (FIH-1). The facts (ⅰ) that many dioxygenases commonly use molecular oxygen and reducing agents during detoxification of xenobiotics, (ⅱ) that detoxification reaction produces radicals and reactive oxygen species, and (ⅲ) that activities of both PHD and FIH-1 are regulated by the changes in the balance between oxygen species and reducing agents, imply the possibility that the activity of HIF-α can be increased during detoxification process. The importance of HIF-α in cancer and ischemic diseases has been emphasized since its target genes mediate various hypoxic responses including angiogenesis, erythropoiesis, glycolysis, pH balance, metastasis, invasion and cell survival. Therefore, activators of PHDs and FIH-1 can be potential anticancer drugs which could reduce the activity of HIF, whereas inhibitors, for preventing ischemic diseases. This review highlights these novel dioxygenases, PHDs and FIH-1 as specific target against not only cancers but also ischemic diseases.