• Genomics & Informatics
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• 제9권4호
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• pp.161-172
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• 2011

Angiogenesis is regulated by a large number of molecules and complex signaling mechanisms. The G protein $G{\alpha}_{13}$ is a part of this signaling mechanism as an endothelial cell movement regulator. Gene expression analysis of $G{\alpha}_{13}$ knockout mouse embryos was carried out to identify the role of $G{\alpha}_{13}$ in angiogenesis signaling during embryonic development. Hypoxia-inducible response factors including those acting as regulators of angiogenesis were over expressed, while genes related to the cell cycle, DNA replication, protein modification and cell-cell dissociation were under expressed. Functional annotation and network analysis indicate that $G{\alpha}_{13}{^{-/-}}$ embryonic mice were exposed to hypoxic conditions. The present analysis of the time course highlighted the significantly high levels of disorder in the development of the cardiovascular system. The data suggested that hypoxia-inducible factors including those associated with angiogenesis and abnormalities related to endothelial cell division contributed to the developmental failure of $G{\alpha}_{13}$ knockout mouse embryos.

• 한국발생생물학회지:발생과생식
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• 제11권1호
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• pp.13-20
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• 2007

암컷 포유동물의 노화 과정에서 생식계는 체내 여러 시스템 가운데 가장 먼저 기능 저하가 나타난다. 생식 노화(reproductive aging) 과정 중인 암컷 포유동물은 비록 종 특이성이 있지만 주기성(cyclicity)의 소실과 같은 생식 능력의 감소와 함께 여러 기능들의 변화가 동반되면서 궁극적으로 인간의 폐경 현상과 같은 생식 능력 상실이 나타난다. 본 증설은 암컷 포유동물의 생식호르몬 축, 특히 신경내분비 회로의 노화에 대한 정보들과 노화 연구에 유용한 설치류 모델들을 소개하고자 한다. 암컷 설치류의 중년(middle age, 생후 $8{\sim}12$개월)은 인간의 폐경기 진입 직전에 해당되는 시기로, 이 시기에 시상하부 GnRH 분비의 맥동성과 급등(surge)이 현저히 지연되기 시작하고, 곧 이어 뇌하수체 LH 분비의 맥동성과 급등이 역시 약화 내지 지연된다. 노화와 관련된 GnRH-LH 신경내분비 활성의 결손은 시상하부 GnRH 뉴런의 활성을 조절하는 여러 자극(예, glutamate)들의 변화와 밀접하게 연관되어 있다. 많은 연구자들이 이러한 '시상하부 결손(hypothalamic defects)'이 생식 노화의 주된 요인임을 지지하지만, inhibin과 같은 난소 요인의 변화 역시 생식 노화의 유도와 관련된 것으로 보인다. 생식 노화를 연구함에 유용한 몇몇 설치류 모델이 있다; FSH 수용체 녹아웃(follitropin receptor knockout; FORKO) 생쥐 모델의 경우는 homozygous(null) 뿐만 아니라 heterozygous(haploinsufficient) 상태도 노화에 따른 난자/난포의 고갈을 나타낸다. Dioxin/aryl hydrocarbon 수용체 녹아웃 (AhRKO) 생쥐 모델도 유사한 상태를 유발할 수 있다. 생식 노화의 기작에 관한 연구는 삶의 질을 높이기 위한 수단들, 예를 들어 호르몬 보충요법(HRT)의 장단점을 평가하고 안전성을 제고하는데 도움이 될 것이다.

• 생명과학회지
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• 제24권5호
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• pp.588-593
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• 2014

본 논문은 RLIP76 단백질이 암, 종양 혈관 신생 및 그 치료에 미치는 중요성을 보고함에 있다. 암의 연구에 있어서, 종양의 혈관 신생을 억제시키는 인자와 영향을 끼치는 인자를 밝혀내는 것은 암의 억제와 치료를 위한 분자 생물학적 기전에 중대한 영향을 미친다. 최근 연구에서, RLIP76 단백질이 혈관 신생에 영향을 끼치는 역할을 발견하였다. RLIP76 제거 마우스의 종양은 일반 종양과 비교하여 혈관의 크기가 작으며, 가늘고, 그 혈관의 수가 적고 길이가 짧은 것으로 보고되고 있다. 게다가, Matrigel plugs을 이용한 혈관 신생 실험에서, RLIP76이 제거된 마우스에서는 혈관 생성이 억제 되었으나, 일반 마우스에서는 혈관이 생성되었다. 또한, 혈관세포를 이용한 in vitro 실험에 있어서, proliferation, migration 및 cord formation 모두가 RLIP76에 의해서 조절되었다. 일반적으로 RLIP76은 대부분의 인간 조직과 종양에서 발현되며, 약의 저항 기전 연구에 이용되고 있기도 한다. 또한, 이RLIP76은 small GTPase R-Ras와 상호작용을 통하여 세포 spreading 및 migration에 관여하고 있다. 이러한 결과는 RLIP76와 암 연구의 중요성을 보고하고 있으며, 혈관 세포의 기능의 기전 및 종양의 혈관 신생을 위한 RLIP76 단백질의 중요성을 알리고 있고, RLIP76의 추가적인 연구를 통하여 종양의 혈관 신생의 기전을 밝히는 것이 필요함을 제안하는 바이다.

• 대한수의학회지
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• 제45권4호
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• pp.517-525
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• 2005

This study was performed to evaluate using wild-type (WT) and $C{\times}32$ knockout (KO) mice if lack of cell to cell communication by connexin 32 gap junction enhances the benzene-induced hematotoxicity and hemopoietic tumor development. The WT and $C{\times}32$ KO mice were exposed to 300 ppm of benzene for 6 hours/day, 5 days/week for a total of 26 weeks by inhalation, and then sacrificed to evaluate the toxicities of hemopoietic organs or allowed to live out their life span to evaluate the hemopoietic tumor incidence. The significant increase and decrease of organ weight were respectively noted in spleen and thymus of both WT and $C{\times}32$ KO mice without significant difference between the genotypes. Histopathologically, benzene exposure for 26 weeks induced the morphological changes in hemopoietic organs, characterized by fat cell accumulation in the bone marrow and extramedullary hemopoiesis in the spleen. The fat cell accumulation was, compared with that of WT mice, considerably exacerbated in the $C{\times}32$ KO mice. However, no significant difference was observed in the changes of hematological values and bone marrow cellularity as well as in the onset and incidence of hemopoietic tumors between WT and $C{\times}32$ KO mice. In conclusion, this study indicated little significant role of the cellular communication by $C{\times}32$ gap junction in the action mechanism of benzene hematotoxicity and leukemogenicity.

• 생명과학회지
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• 제27권8호
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• pp.873-878
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• 2017

본 연구는 대식세포 활성화 과정에서 NQO1의 역할을 확인하는 것이다. 대식세포의 활성화 정도는 배양액으로 분비하는 IL-6와 $TNF-{\alpha}$ 양을 측정하여 평가하였다. 먼저 NQO1 WT 생쥐와 NQO1 KO 생쥐에서 각각 분리한 복강대식세포의 활성화 정도를 비교해 보았다. 특이하게도 NQO1 KO 복강대식세포가 NQO1 WT에 비해서 더 높게 활성화되어 있었다. 또한 일반 생쥐의 복강대식세포에 NQO1 억제제(dicumarol)을 처치한 경우에도 강한 활성이 유도됨을 확인하였다. Dicumarol을 처치한 RAW264.7 (대식세포주)에 서도 강한 활성화가 관찰되었다. 이는 NQO1이 대식세포의 활성화 과정을 억제하는 경로와 연관되어 있음을 보여준다. 더욱이 dicumarol을 처치하여 NQO1의 기능을 억제시킨 다양한 대식세포에서 $I{\kappa}B$ 단백질이 유의하게 감소한다는 사실을 확인하였다. 대식세포 활성화 과정을 매개하는 주요 신호분자가 $NF{\kappa}B$이며 이 분자에 대한 억제자가 $I{\kappa}B$라는 사실들을 감안할 때, NQO1의 기능이 $I{\kappa}B$ 단백질변성 억제와 연관되어 있으며 이를 통해 대식세포의 활성화를 차단했을 가능성이 있다. 본 연구는 향 후 대식세포 활성화 과정을 조절하는 NQO1의 역할을 규명하는데 있어서 중요한 기초 결과가 될 것이다.

• BMB Reports
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• 제46권2호
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• pp.103-106
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• 2013

Phosphoinositide 3-kinases (PI3Ks) play key roles in synaptic plasticity and cognitive functions in the brain. We recently found that genetic deletion of $PI3K{\gamma}$, the only known member of class IB PI3Ks, results in impaired N-methyl-D-aspartate receptor-dependent long-term depression (NMDAR-LTD) in the hippocampus. The activity of RalA, a small GTP-binding protein, increases following NMDAR-LTD inducing stimuli, and this increase in RalA activity is essential for inducing NMDAR-LTD. We found that RalA activity increased significantly in $PI3K{\gamma}$ knockout mice. Furthermore, NMDAR-LTD-inducing stimuli did not increase RalA activity in $PI3K{\gamma}$ knockout mice. These results suggest that constitutively increased RalA activity occludes further increases in RalA activity during induction of LTD, causing impaired NMDAR-LTD. We propose that $PI3K{\gamma}$ regulates the activity of RalA, which is one of the molecular mechanisms inducing NMDAR-dependent LTD.

• Molecules and Cells
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• 제37권1호
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• pp.24-30
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• 2014

Inductive expression of early growth response 1 (Egr-1) in neurons is associated with many forms of neuronal activity. However, only a few Egr-1 target genes are known in the brain. The results of this study demonstrate that Egr-1 knockout (KO) mice display impaired contextual extinction learning and normal fear acquisition relative to wild-type (WT) control animals. Genome-wide microarray experiments revealed 368 differentially expressed genes in the hippocampus of Egr-1 WT exposed to different phases of a fear conditioning paradigm compared to gene expression profiles in the hippocampus of KO mice. Some of genes, such as serotonin receptor 2C (Htr2c), neuropeptide B (Npb), neuronal PAS domain protein 4 (Npas4), NPY receptor Y1 (Npy1r), fatty acid binding protein 7 (Fabp7), and neuropeptide Y (Npy) are known to regulate processing of fearful memories, and promoter analyses demonstrated that several of these genes contained Egr-1 binding sites. This study provides a useful list of potential Egr-1 target genes which may be regulated during fear memory processing.

• Biomolecules & Therapeutics
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• 제27권2호
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• pp.134-144
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• 2019

The prevalence of nonalcoholic fatty liver disease (NAFLD) has increased with the incidence of obesity; however, the underlying mechanisms are unknown. In this study, high-resolution metabolomics (HRM) along with transcriptomics were applied on animal models to draw a mechanistic insight of NAFLD. Wild type (WT) and catalase knockout (CKO) mice were fed with normal fat diet (NFD) or high fat diet (HFD) to identify the changes in metabolic and transcriptomic profiles caused by catalase gene deletion in correspondence with HFD. Integrated omics analysis revealed that cholic acid and $3{\beta}$, $7{\alpha}$-dihydroxy-5-cholestenoate along with cyp7b1 gene involved in primary bile acid biosynthesis were strongly affected by HFD. The analysis also showed that CKO significantly changed all-trans-5,6-epoxy-retinoic acid or all-trans-4-hydroxy-retinoic acid and all-trans-4-oxo-retinoic acid along with cyp3a41b gene in retinol metabolism, and ${\alpha}/{\gamma}$-linolenic acid, eicosapentaenoic acid and thromboxane A2 along with ptgs1 and tbxas1 genes in linolenic acid metabolism. Our results suggest that dysregulated primary bile acid biosynthesis may contribute to liver steatohepatitis, while up-regulated retinol metabolism and linolenic acid metabolism may have contributed to oxidative stress and inflammatory phenomena in our NAFLD model created using CKO mice fed with HFD.

• Journal of Ginseng Research
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• 제47권1호
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• pp.144-154
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• 2023

Background: As the major pathophysiological feature of obstructive sleep apnea (OSA), chronic intermittent hypoxia (CIH) is vital for the occurrence of cardiovascular complications. The activation of calpain-1 mediates the production of endothelial reactive oxygen species (ROS) and impairs nitric oxide (NO) bioavailability, resulting in vascular endothelial dysfunction (VED). Ginsenoside Rg1 is thought to against endothelial cell dysfunction, but the potential mechanism of CIH-induced VED remains unclear. Methods: C57BL/6 mice and human coronary artery endothelial cells (HCAECs) were exposed to CIH following knockout or overexpression of calpain-1. The effect of ginsenoside Rg1 on VED, oxidative stress, mitochondrial dysfunction, and the expression levels of calpain-1, PP2A and p-eNOS were detected both in vivo and in vitro. Results: CIH promoted VED, oxidative stress and mitochondrial dysfunction accompanied by enhanced levels of calpain-1 and PP2A and reduced levels of p-eNOS in mice and cellular levels. Ginsenoside Rg1, calpain-1 knockout, OKA, NAC and TEMPOL treatment protected against CIH-induced VED, oxidative stress and mitochondrial dysfunction, which is likely concomitant with the downregulated protein expression of calpain-1 and PP2A and the upregulation of p-eNOS in mice and cellular levels. Calpain-1 overexpression increased the expression of PP2A, reduced the level of p-eNOS, and accelerated the occurrence and development of VED, oxidative stress and mitochondrial dysfunction in HCAECs exposed to CIH. Moreover, scavengers of O₂^·-, H₂O₂, complex I or mitoKATP abolished CIH-induced impairment in endothelial-dependent relaxation. Conclusion: Ginsenoside Rg1 may alleviate CIH-induced vascular endothelial dysfunction by suppressing the formation of mitochondrial reactive oxygen species through the calpain-1 pathway.

• Nutrition Research and Practice
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• 제1권4호
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• pp.247-253
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• 2007

Alpha-tocopherol transfer protein (${\alpha}$-TTP) is a liver cytosolic transport protein that faciliates ${\alpha}$-tocopherol (${\alpha}$-T) transfer into liver secreted plasma lipoproteins. Genetic defects in ${\alpha}$-TTP, like dietary vitamin E deficiency, are associated with infertility, muscular weakness and neurological disorders. Both human and ${\alpha}$-TTP deficient (${\alpha}-TTP^{-/-}$) mice exhibit severe plasma and tissue vitamin E deficiency that can be attenuated by sufficient dietary ${\alpha}$-T supplementations. In this review, we summarize the literature concerning studies utilizing the ${\alpha}-TTP^{-/-}$ mice. Levels of vitamin E in the ${\alpha}-TTP^{-/-}$ mice do not appear to be directly related to the amounts of dietary ${\alpha}$-T or to the levels of ${\alpha}$-TTP protein in tissues. The ${\alpha}-TTP^{-/-}$ mice appear to present a good model for investigating the specific role of ${\alpha}$-T in tissue vitamin E metabolism. Furthermore, ${\alpha}-TTP^{-/-}$ mice appear to be useful to elucidate functions of ${\alpha}$-TTP beyond its well recognized functions of transferring ${\alpha}$-T from liver to plasma lipoprotein fractions.