• Asian-Australasian Journal of Animal Sciences
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• v.18 no.4
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• pp.483-489
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• 2005

To understand the molecular mechanisms that regulate intramuscular fat deposition and its release, cDNA clones expressed in adipose tissues of Korean cattle were identified by differential screening from adipose tissue cDNA library. By partial nucleotide sequencing of 486 clones and a search for sequence similarity in NCBI nucleotide databases, 245 clones revealed unique clones. By a functional grouping of the clones, 14% of the clones were categorized to metabolism and enzyme-related group (stearoyl CoA desaturase, lactate dehydrogenase, fatty acid synthase, ATP citrate lyase, lipoprotein lipase, acetyl CoA synthetase, etc), and 6% to signal transduction/cell cycle-related group (C/EBP, cAMP-regulated phosphoprotein, calmodulin, cyclin G1, cyclin H, etc), and 4% to cytoskeleton and extracellular matrix components (vimentin, ankyrin 2, gelosin, syntenin, talin, prefoldin 5). The obtained 245 clones will be useful to study lipid metabolism and signal transduction pathway in adipose tissues and to study obesity in human. Some clones were subjected to full-sequencing containing open reading frame. The cDNA clone of bovine homolog of human prefoldin 5 gene had a total length of 959 nucleotides coding for 139 amino acids. Comparison of the deduced amino acid sequences of bovine prefoldin 5 with those of human and mouse showed over 95% identity. The cDNA clone of bovine homolog of human ubiquitin-like/S30 ribosomal fusion protein gene had a total length of 484 nucleotides coding for 133 amino acids. Comparison of the deduced amino acid sequences of bovine ubiquitin-like/S30 ribosomal fusion protein gene with those of human, rat and mouse showed over 97% identity. The cDNA clone of bovine homolog of human proteolipid protein 2 mRNA had a total length of 928 nucleotides coding for 152 amino acids. Comparison of the deduced amino acid sequences of bovine proteolipid protein 2 with those of human and mouse showed 87.5% similarity. The cDNA clone of bovine homolog of rat thymosin beta 4 had a total length of 602 nucleotides coding for 44 amino acids. Comparison of the deduced amino acid sequences of bovine thymosin beta 4 gene with those of human, mouse and rat showed 93.1% similarity. The cDNA clone of bovine homolog of human myotrophin mRNA had a total length of 790 nucleotides coding for 118 amino acids. Comparison of the deduced amino acid sequences of bovine myotrophin gene with those of human, mouse and rat showed 83.9% similarity. The functional role of these clones in adipose tissues needs to be established.

• The Korean Journal of Zoology
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• v.39 no.4
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• pp.337-351
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• 1996

Melatonin Is a multifunctional hormone secreted from the pineal gland in the middle of cerebrum and cerebellum. Its synthesis and release reflect photopedod;Photopedod is a yearly predictable ambient factor that most animals utilize as an environmental cue for maximum survival. Hamsters maintaln reproductive activity in summer during which day length exceeds night time. Upon the advent of autumnal equinox they undergo gonadal regression. The photoperiodic effects are prevented by removal of the pineal gland and restored by the timed repiacument of melatonin. The results suggest that melatonin constitutes part of control mechanism whereby environmental information is transduced to neuroendocrine signal responsIble for the functional integrity of the reproductive system. From the studies for the action site of melatonin following the treatment of photopedod or melatonin in the lesion of a spedflc portion of hypothalamus, suprachiasmatic nuclei and pars tuberalis are shown to be a consensus site for melatonIn. The action of melatonin. In the regulation of reproduction is largely unknown. It is mainly due to the lack of acute effect of melatonin on gonadotropin secretion. However, reduction of the gonadotropln release and augmentation of the hypothalamic gonadotropin-releasing hormone (GnRH) content by long-term treatment of melatonln Indicate that constant presence of melatonln may partidpate in the regulation of sexual activity via the GnRH neuronal system. The action mechanism by which melatonin exerts Its effect on GnRH neuron needs to be eluddated. The inability of opiold analogues to affect the reproductive hormones in sexually regressed animals by inhibftory photopedod and melatonin suggests that the opioldergic neuron may be a prime intervening mediator. Recent cloning of melatonin receptor will contribute to investigate its anatomical Identification and the action mechanism of melatonin on target tissues at the molecular level.

• International Journal of Oral Biology
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• v.36 no.4
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• pp.173-178
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• 2011

Tumor necrosis factor alpha ($TNF{\alpha}$) is a multifunctional cytokine that is elevated in inflammatory diseases such as atherosclerosis, diabetes and rheumatoid arthritis. Recent evidence has suggested that ${\beta}2$ adrenergic receptor (${\beta}2AR$) activation in osteoblasts suppresses osteogenic activity. In the present study, we explored whether $TNF{\alpha}$ modulates ${\beta}AR$ expression in osteoblastic cells and whether this regulation is associated with the inhibition of osteoblast differentiation by $TNF{\alpha}$. In the experiments, we used C2C12 cells, MC3T3-E1 cells and primary cultured mouse bone marrow stromal cells. Among the three subtypes of ${\beta}AR$, ${\beta}2$ and ${\beta}3AR$ were found in our analysis to be upregulated by $TNF{\alpha}$. Moreover, isoproterenol-induced cAMP production was observed to be significantly enhanced in $TNF{\alpha}$-primed C2C12 cells, indicating that $TNF{\alpha}$ enhances ${\beta}2AR$ signaling in osteoblasts. $TNF{\alpha}$ was further found in C2C12 cells to suppress bone morphogenetic protein 2-induced alkaline phosphatase (ALP) activity and the expression of osteogenic marker genes including Runx2, ALP and osteocalcin. Propranolol, a ${\beta}2AR$ antagonist, attenuated this $TNF{\alpha}$ suppression of osteogenic differentiation. $TNF{\alpha}$ increased the expression of receptor activator of NF-${\kappa}B$ ligand (RANKL), an essential osteoclastogenic factor, in C2C12 cells which was again blocked by propranolol. In summary, our data show that $TNF{\alpha}$ increases ${\beta}2AR$ expression in osteoblasts and that a blockade of ${\beta}2AR$ attenuates the suppression of osteogenic differentiation and stimulation of RANKL expression by $TNF{\alpha}$. These findings imply that a crosstalk between $TNF{\alpha}$ and ${\beta}2AR$ signaling pathways might occur in osteoblasts to modulate their function.

• Annals of Clinical Neurophysiology
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• v.13 no.2
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• pp.80-86
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• 2011

Background: A dry-type electrode is an alternative to the conventional wet-type electrode, because it can be applied without any skin preparation, such as a conductive electrolyte. However, because a dry-type electrode without electrolyte has high electrode-to-skin impedance, an impedance-converting amplifier is typically used to minimize the distortion of the bioelectric signal. In this study, we developed an active dry electroencephalography (EEG) electrode using an impedance converter, and compared its performance with a conventional Ag/AgCl EEG electrode. Methods: We developed an active dry electrode with an impedance converter using a chopper-stabilized operational amplifier. Two electrodes, a conventional Ag/AgCl electrode and our active electrode, were used to acquire EEG signals simultaneously, and the performance was tested in terms of (1) the electrode impedance, (2) raw data quality, and (3) the robustness of any artifacts. Results: The contact impedance of the developed electrode was lower than that of the Ag/AgCl electrode ($0.3{\pm}0.1$ vs. $2.7{\pm}0.7\;k{\Omega}$, respectively). The EEG signal and power spectrum were similar for both electrodes. Additionally, our electrode had a lower 60-Hz component than the Ag/AgCl electrode (16.64 vs. 24.33 dB, respectively). The change in potential of the developed electrode with a physical stimulus was lower than for the Ag/AgCl electrode ($58.7{\pm}30.6$ vs. $81.0{\pm}19.1\;{\mu}V$, respectively), and the difference was close to statistical significance (P=0.07). Conclusions: Our electrode can be used to replace Ag/AgCl electrodes, when EEG recording is emergently required, such as in emergency rooms or in intensive care units.

• Journal of Ginseng Research
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• v.44 no.2
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• pp.341-349
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• 2020

Background: The replicative senescence of human dermal fibroblasts (HDFs) is accompanied by growth arrest. In our previous study, the treatment of senescent HDFs with Rg3(S) lowered the intrinsic reactive oxygen species (ROS) levels and reversed cellular senescence by inducing peroxiredoxin-3, an antioxidant enzyme. However, the signaling pathways involved in Rg3(S)-induced senescence reversal in HDFs and the relatedness of the stereoisomer Rg3(R) in corresponding signaling pathways are not known yet. Methods: We performed senescence-associated β-galactosidase and cell cycle assays in Rg3(S)-treated senescent HDFs. The levels of ROS, adenosine triphosphate (ATP), and cyclic adenosine monophosphate (cAMP) as well as the mitochondrial DNA copy number, nicotinamide adenine dinucleotide (NAD)⁺/1,4-dihydronicotinamide adenine dinucleotide (NADH) ratio, and NAD-dependent sirtuins expression were measured and compared among young, old, and Rg3(S)-pretreated old HDFs. Major signaling pathways of phosphatidylinositol 3-kinase/Akt, 5' adenosine monophosphate-activated protein kinase (AMPK), and sirtuin 1/3, including cell cycle regulatory proteins, were examined by immunoblot analysis. Results: Ginsenoside Rg3(S) reversed the replicative senescence of HDFs by restoring the ATP level and NAD⁺/NADH ratio in downregulated senescent HDFs. Rg3(S) recovered directly the cellular levels of ROS and the NAD⁺/NADH ratio in young HDFs inactivated by rotenone. Rg3(S) mainly downregulated phosphatidylinositol 3-kinase/Akt through the inhibition of mTOR by cell cycle regulators like p53/p21 in senescent HDFs, whereas Rg3(R) did not alter the corresponding signaling pathways. Rg3(S)-activated sirtuin 3/PGC1α to stimulate mitochondrial biogenesis. Conclusion: Cellular molecular analysis suggests that Rg3(S) specifically reverses the replicative senescence of HDFs by modulating Akt-mTOR-sirtuin signaling to promote the biogenesis of mitochondria.

• Journal of Life Science
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• v.26 no.6
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• pp.737-748
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• 2016

By this time, insect antimicrobial peptides (AMPs) have been characterized more than 150 peptides since purification of cecropin in the hemolymph of pupae from Hyalophora cecropia in 1980. Therefore, it is considered that insects are good sources of AMP selection. Insect AMPs are small (low molecular weight) and cationic, and amphipathic with variable length, sequence, and structure. They perform a pivotal role on humoral immunity in the insect innate immune system against invading pathogens such as bacteria, fungi, parasites, and viruses. Most of the insect AMPs are induced rapidly in the fat bodies and other specific tissues of insects after septic injury or immune challenge. Then the AMPs subsequently released into the hemolymph to act against microorganisms. These peptides have a broad antimicrobial spectrum against various microbes including anticancer activities. Insect AMPs could be divided into four families based on their structures and sequences. That is the α-helical peptides, cysteine-rich peptides, proline-rich peptides, and glycine-rich peptides/proteins. For instance, cecropins, insect defensins, proline-rich peptides, and attacins are common insect AMPs, but gloverins and moricins have been identified only in lepidopteran species. This review focuses on AMPs from insects and discusses current knowledge and recent progress with potential applications of insect AMPs.

• Molecules and Cells
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• v.38 no.2
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• pp.138-144
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• 2015

Raloxifene is a selective estrogen receptor modulator (SERM) that binds to the estrogen receptor (ER), and exhibits potent anti-tumor and autophagy-inducing effects in breast cancer cells. However, the mechanism of raloxifene-induced cell death and autophagy is not well-established. So, we analyzed mechanism underlying death and autophagy induced by raloxifene in MCF-7 breast cancer cells. Treatment with raloxifene significantly induced death in MCF-7 cells. Raloxifene accumulated GFP-LC3 puncta and increased the level of autophagic marker proteins, such as LC3-II, BECN1, and ATG12-ATG5 conjugates, indicating activated autophagy. Raloxifene also increased autophagic flux indicators, the cleavage of GFP from GFP-LC3 and only red fluorescence-positive puncta in mRFP-GFP-LC3-expressing cells. An autophagy inhibitor, 3-methyladenine (3-MA), suppressed the level of LC3-II and blocked the formation of GFP-LC3 puncta. Moreover, siRNA targeting BECN1 markedly reversed cell death and the level of LC3-II increased by raloxifene. Besides, raloxifene-induced cell death was not related to cleavage of caspases-7, -9, and PARP. These results indicate that raloxifene activates autophagy-dependent cell death but not apoptosis. Interestingly, raloxifene decreased the level of intracellular adenosine triphosphate (ATP) and activated the AMPK/ULK1 pathway. However it was not suppressed the AKT/mTOR pathway. Addition of ATP decreased the phosphorylation of AMPK as well as the accumulation of LC3-II, finally attenuating raloxifene-induced cell death. Our current study demonstrates that raloxifene induces autophagy via the activation of AMPK by sensing decreases in ATP, and that the overactivation of autophagy promotes cell death and thereby mediates the anti-cancer effects of raloxifene in breast cancer cells.

• Development and Reproduction
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• v.24 no.3
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• pp.231-239
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• 2020

Many benefits of silk protein fibroin (SPF) have been suggested in biomedical applications; and notably, significant SPF effects have been observed for metabolic syndromes that are directly linked to insulin resistance, such as type 2 diabetes mellitus (T2DM). Based on our previous findings, we believe that SPF from spiders exhibits outstanding glucose-lowering effects in diabetic BKS.Cg-m+/+Lepr^db mice. In order to evaluate the dietary effects of SPF in diabetic animals, we generated several lines of transgenic rice (TR) that expresses SPF, and the feeding of TR-SPF to diabetic animals decreased blood glucose levels, but did not change insulin levels. Western blot analyses of hepatic proteins showed that AMP-activated protein kinase (AMPK) expression and phosphorylation both decreased in TR-SPF-fed groups, compared with controls. This finding suggests that the glucose-lowering effects in this diabetic animal model might be AMPK-independent. In contrast, six-transmembrane protein of prostate 2 (STAMP2) was upregulated after TR-SPF exposure. Together with STAMP2, the Akt protein phosphorylation increased after TR-SPF exposure, which indicates that STAMP2 leads to Akt phosphorylation and thus increases insulin sensitivity in hepatocytes. Importantly, the hepatic steatosis that was seen in the liver of diabetic mice was remarkably alleviated in TR-SPF-fed mice. Hepatocytes that were immunopositive for STAMP2 were overwhelmingly observed in hepatic tissues from TR-SPF-fed mice compared to the control. Taken together, these results suggest that feeding diabetic mice with TR-SPF upregulates STAMP2 expression and increases Akt phosphorylation in hepatic tissues and thus potentially alleviates insulin resistance and hepatic steatosis.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.129-134
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• 1996

1차 년도 G-7 개발 과제로 수행된 자기 공명 진단 장치 (Magnetic Resonance Imaging System)의 개발 내용을 간략히 소개하였다. 성공적인 IT Compact 자기 공명 진단 장치의 완성을 위해 일차적으로 (1)RF (고주파), Gradient(경사 자계), Spectrometer 등의 Hard-ware 관련 MRI 핵심부분, (2) RF, Gradient, Spectrometer, Magnet 등의 각 Sub-system을 연결, 조합, 조정하여 하나의 체계적인 시스템으로 통합하고 운영하는 과정(System Integration), (3)사용자와 시스템을 연결하는 User Interface, Data Base Management, Real time 운영 SW 등과 (4)임상에 적용하여 구체적인 성능과 효용성을 확인하는 기술 등에 대하여 집중 연구하였다. 개발 방법은 (1)지난 16년간 국내에 축적 된 연구 개발 인력들을 최대한 활용하고 (2)연구 개발을 국제화 시켜 필요한 경우 부분별로 개발 인력을 해외에서 보완하고 (3)소수 정예 전문 인력 주의와 요소 기술 또는 중요 부품을 경쟁성 검토 후 필요 시 Out-sourcing 활용으로 최저의 비용으로 개발 기간을 최소화 하는 데 두었다. 개발된 1.0Tesla자기 공명 영상 장치는 미국 물리 학회에서 규격화한 Phantom및 임상 적용을 통하여 서울대 의대 연구 팀과 지속적으로 성능을 평가해 왔다. 개발된 시스템의 해상도는 $256{\times}256$ head 영상에서 1mm 이 하의 해상도를 가짐을 resolution phantom 을 통하여 확인할 수 있었고, $512{\times}512$ 영상에서 는 약 0.5 mm 의 물체를 분리 해냄으로써 외제 시스템들 보다 우수하게 평가 되었다. 차폐 경사코일의 Eddy current영향은2%이내로 촬영 시 영향은 거의 무시할 수 있었다. 또한, 개발된 영상 기법들, 즉 Multislice/Multi Echo, Oblique angle imaging, 64 Echo train을 갖는 고속 촬영 기술들이 자기 공명 장치에 장착되어 임상 적용에 문제가 없도록 하였다. 또한 20mT/m/Amp의 강력한 능동 차폐 경사 자계 코일(Active Shield Gradient Coil)을 기본 사양으로 하고, 수신단을 최대 6개로 확장토록 하여 2차년도의 초고속 촬영 기법(EPI) 및 Phased Array 코일 촬영이 가능토록 하였다. 1차 년도 개발 과제 수행 결과와 향후 개발 과제를 바탕으로 최종 목표인 국제 경쟁력이 있는 자기 공명 진단 장치 즉 기능과 영상의 질은 선진국 제품과 동일하거나 우수하되, 저가격을 구현한 상용화 제품이 완성되어, 첨단 의료기기로서 산업 구조 고도화에 기여하고 수입대체 뿐만 아니 라 수출을 통한 국익 창출과 국가의 기술을 통한 위상 제고에 기여되길 기대한다.

• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.1
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• pp.18-26
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• 2015

Akebiae Caulis is a galenical originated from Akebia quinata Decaisne species. It is commonly used in the treatment of oposiuria, inflammation, nociceptive and fever. Here, we investigated the effect of Akebiae Caulis extract (ACE) to protect hepatocyte against the malfunction of mitochondria and apoptosis. Arachidonic acid (AA)+iron promoted excessive reactive oxygen species (ROS) production and exerted a deleterious effect on mitochondria. Treatment with ACE protected hepatocytes from AA+iron-induced cytotoxicity, as shown by alterations in the protein levels related with apoptosis such as poly(ADP-ribose) polymerase, pro-caspase 3, Bcl-XL and Bcl-2. Moreover, AA+iron-induced $H_2O_2$ production, GSH depletion and mitochondrial dysfunction were alleviated by ACE pretreatment. As a potential molecular mechanism for the ACE-mediated cytoprotection, phosphorylation of AMP-activated protein kinase (AMPK), a key regulator in determining cell survival or death, was increased by ACE. Moreover, ACE treatment enhanced inactive phosphorylation of glycogen synthase kinase-$3{\beta}$ ($GSK3{\beta}$), downstream substrate kinase of AMPK. More importantly, ACE prevented a decrease in the $GSK3{\beta}$ phosphorylation derived by AA+iron, which might contribute to mitohondiral protection and cell survival. To further identify essential compounds in Akebiae Caulis for the protection of AA+iron-mediated cytotoxicity, we found that betulin in combination with hederagenin protected from AA+iron-induced mitochondrial dysfunction. Betulin+hederagenin treatment also increased inactive phosphorylation of $GSK3{\beta}$ in common with ACE. These results suggest that ACE protected hepatocytes against oxidative stress and mitochondrial dysfunction, which is mediated with inactive $GSK3{\beta}$ phosphorylation downstream of AMPK.