• Journal of Microbiology and Biotechnology
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• 제16권1호
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• pp.84-91
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• 2006

A Saccharomyces cerevisiae pgs1 nulI mutant, which is deficient with phosphatidyl glycerol (PG) and cardiolipin (CL) biosynthesis, grows well on most fermentable carbon sources, but fails to grow on non-fermentable carbon sources such as glycerol, ethanol, and lactate. This mutant also cannot grow on galactose medium as the sole carbon source. We found that the incorporation of $[^{14}C]-galactose$, which is the first step of the galactose metabolic pathway (Leloir pathway), into the pgs 1 null mutant cell was extremely repressed. Exogenously expressed PGS1 (YCpPGS1) under indigenous promoter could completely restore the pgs1 growth defect on non-fermentable carbon sources, and dramatically recovered $[^{14}C]-galactose$ incorporation into the pgs1 mutant cell. However, PGS1 expression under the GALl promoter $(YEpP_{GAL1}-PGS1myc)$ could not complement pgs1 mutation, and the GAL2-lacZ fusion gene $(YEpP_{GAL2}-lacZ)$ also did not exhibit its $\beta-galactosidase$ activity in the pgs1 mutant. In wild-type yeast, antimycin $A(1\;{\mu}g/ml)$, which inhibits mitochondrial complex III, severely repressed not only the expression of the GAL2-lacZ fusion gene, but also uptake of $[^{14}C]-galactose$. However, exogenously expressed PGS1 partially relieved these inhibitory effects of antimycin A in both the pgs1 mutant and wild-type yeast, although it could not basically restore the growth defect on galactose by antimycin A. These results suggest that the PGSI gene product has an important role in utilization of galactose by Gal genes, and that intact mitochondrial function with PGS1 should be required for galactose incorporation into the Leloir pathway. The PGS1 gene might provide a clue to resolve the historic issue about the incapability of galactose with deteriorated mitochondrial function.

• 생명과학회지
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• 제31권5호
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• pp.464-474
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• 2021

대사성질환, 암, 손상, 및 패혈증 등에 의해 유도되는 염증은 산화스트레스를 통해 세포의 미토콘드리아의 기능을 감퇴시켜 신경증과 근육위축증 등을 야기한다. 본 연구에서는 lipopolysaccharide (LPS)에 의해 유도된 미토콘 드리아의 기능감퇴와 근육위측증에 대한 butyrate의 억제효과를 확인하고자 하였다. LPS의 처리는 C2C12세포에서 MAPK의 활성을 통해 미토콘드리아 분열을 촉진하는 DRP1 (Ser616) 인산화와 Atrogin-1의 발현을 증가시켰다. 그러나 butyrate를 처리한 C2C12세포에서는 LPS 처리에 의한 염증 효과가 유의적으로 감소하며, 미토콘드리아 분열을 억제하는 DRP1 (Ser637)의 인산화와 mitofugin2 (Mfn2)의 발현을 증가를 유도하는 것을 확인하였다. 또한 butyrate를 처리한 세포에서 대사성질환을 유발하는 pyruvate dehydrogenase kinase 4 (PDK4)의 발현을 억제함이 관찰되었다. 이는 butyrate가 포도당 대사에서 염증에 의해 유도되는 Warburg 효과를 억제하여 산화스트레스를 개선함으로써, JNK의 활성을 억제하는 것으로 확인되었다. 이러한 결과들은 butyrate가 항산화효과를 통해 패혈증과 대사성질환과 같은 염증에 의해 유도되는 미토콘드리아의 기능 감퇴와 이에 따른 근육위축증을 개선할 수 있는 후보물질로 활용될 가능성이 있을 것으로 기대된다.

• Annals of Clinical Neurophysiology
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• 제21권1호
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• pp.57-60
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• 2019

Axonal Charcot-Marie-Tooth disease (CMT2) has most frequently been associated with mutations in the MFN2 gene. MFN2 encodes mitofusin 2, which is a mitochondrial fusion protein that plays an essential role in mitochondrial function. We report CMT2 in a Korean father and his son that manifested with gait difficulties and progressive atrophy of the lower legs. Molecular analysis revealed a novel heterozygous c.2096T>C (p.Leu699Pro) mutation in the exon 18 of MFN2 in both subjects. We suggest that this novel mutation in MFN2 is probably a pathogenic mutation for CMT2.

• Molecules and Cells
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• 제24권1호
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• pp.95-104
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• 2007

The mechanism of acacetin-induced apoptosis of human breast cancer MCF-7 cells was investigated. Acacetin caused 50% growth inhibition ($IC_{50}$) of MCF-7 cells at $26.4{\pm}0.7{\mu}M$ over 24 h in the MTT assay. Apoptosis was characterized by DNA fragmentation and an increase of sub-G1 cells and involved activation of caspase-7 and PARP (poly-ADP-ribose polymerase). Maximum caspase 7 activity was observed with $100{\mu}M$ acacetin for 24 h. Caspase 8 and 9 activation cascades mediated the activation of caspase 7. Acacetin caused a reduction of Bcl-2 expression leading to an increase of the Bax:Bcl-2 ratio. It also caused a loss of mitochondrial membrane potential that induced release of cytochrome c and apoptosis inducing factor (AIF) into the cytoplasm, enhancing ROS generation and subsequently resulting in apoptosis. Pretreatment of cells with N-acetylcysteine (NAC) reduced ROS generation and cell growth inhibition, and pretreatment with NAC or a caspase 8 inhibitor (Z-IETD-FMK) inhibited the acacetin-induced loss of mitochondrial membrane potential and release of cytochrome c and AIF. Stress-activated protein kinase/c-Jun $NH_4$-terminal kinase 1/2 (SAPK/JNK1/2) and c-Jun were activated by acacetin but extracellular-regulated kinase 1/2 (Erk1/2) nor p38 mitogen-activated protein kinase (MAPK) were not. Our results show that acacetin-induced apoptosis of MCF-7 cells is mediated by caspase activation cascades, ROS generation, mitochondria-mediated cell death signaling and the SAPK/JNK1/2-c-Jun signaling pathway, activated by acacetin-induced ROS generation.

• 한국동물생명공학회지
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• 제36권4호
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• pp.189-193
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• 2021

Jak-STAT pathway is required for embryogenesis, female gametogenesis, cytokine-mediated neuroprotection, diabetes, obesity, cancer, stem cell, and various tissues. The noncanonical role of Jak-STAT in mitochondria function was supported by the detection of STAT protein in mitochondria, however, several studies show that STAT protein is detected in the endoplasmic reticulum (ER), and not in mitochondria. STAT protein may alter mitochondria function without entering mitochondria, this involves regulation of fission and fusion proteins to change mitochondria morphology. However, how changes in mitochondria morphology lead to changes in mitochondria metabolism needs further investigation.

• Molecules and Cells
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• 제43권1호
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• pp.76-85
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• 2020

MARCH5 is a RING finger E3 ligase involved in mitochondrial integrity, cellular protein homeostasis, and the regulation of mitochondrial fusion and fission. To determine the function of MARCH5 during development, we assessed transcript expression in zebrafish embryos. We found that march5 transcripts were of maternal origin and evenly distributed at the 1-cell stage, except for the mid-blastula transition, with expression predominantly in the developing central nervous system at later stages of embryogenesis. Overexpression of march5 impaired convergent extension movement during gastrulation, resulting in reduced patterning along the dorsoventral axis and alterations in the ventral cell types. Overexpression and knockdown of march5 disrupted the organization of the developing telencephalon and diencephalon. Lastly, we found that the transcription of march5 was tightly regulated by the transcriptional regulators CHOP, C/EBPα, Staf, Znf143a, and Znf76. These results demonstrate the essential role of March5 in the development of zebrafish embryos.

• Journal of Microbiology and Biotechnology
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• 제33권2호
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• pp.242-250
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• 2023

Comparative gene identification-58 (CGI-58) is an activating protein of triacylglycerol (TAG) lipase. It has a variety of catalytic activities whereby it may play different roles in diverse organisms. In this study, a homolog of CGI-58 in Phaeodactylum tricornutum (PtCGI-58) was identified. PtCGI-58 was localized in mitochondria by GFP fusion protein analysis, which is different from the reported subcellular localization of CGI-58 in animals and plants. Respectively, PtCGI-58 overexpression resulted in increased neutral lipid content and TAG accumulation by 42-46% and 21-32%. Likewise, it also increased the relative content of eicosapentaenoic acid (EPA), and in particular, the EPA content in TAGs almost doubled. Transcript levels of genes involved in de novo fatty acid synthesis and mitochondrial β-oxidation were significantly upregulated in PtCGI-58 overexpression strains compared with wild-type cells. Our findings suggest that PtCGI-58 may mediate the breakdown of lipids in mitochondria and the recycling of acyl chains derived from mitochondrial β-oxidation into TAG biosynthesis. Moreover, this study potentially illuminates new functions for CGI-58 in lipid homeostasis and provides a strategy to enrich EPA in algal TAGs.

• Journal of Nutrition and Health
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• 제57권1호
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• pp.53-64
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• 2024

본 연구는 근생성 효능을 가진 천연화합물을 발굴하고자 oxypeucedanin hydrate가 근생성과 미토콘드리아에 미치는 영향 및 항암제 유도 미토콘드리아 손상에 대한 완화효과를 C2C12 근원세포와 zebrafish 모델을 통해 각각 확인하였다. 그 결과, oxypeucedanin hydrate는 다핵의 근관세포의 수와 분화말기 표지자인 Myh4의 발현량을 증가시켰고 근육단백질 분해 인자인 MuRF1과 MAFbx의 발현량은 감소시켰다. 또한 미토콘드리아 생합성 조절인자인 Pgc1α, Tfam과 전자전달계 구성인자인 Sdha, Cox1의 발현은 증가시키고, 미토콘드리아 융합인자인 Opa1의 발현 또한 증가시킴과 동시에 미토콘드리아 분열을 표지하는 Drp1의 발현은 감소시켰다. 한편 zebrafish 모델을 통해 항암제 유도 미토콘드리아 손상에 대한 개선효과를 확인한 결과, oxypeucedanin hydrate는 항암제에 의해 유도된 미토콘드리아 손상을 완화시켰다. 이상의 결과들은 oxypeucedanin hydrate가 미토콘드리아 기능 증진을 매개로 근원세포 분화 촉진 및 근육 단백질 분해 저하 효과를 나타냄을 시사한다. 따라서 본 연구를 통해 oxypeucedanin hydrate가 근생성 효과를 나타낼 수 있는 잠재적인 유효소재로서의 가능성을 제시하였다.

• Journal of Nutrition and Health
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• 제39권4호
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• pp.323-330
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• 2006

Peripheral insulin resistance in obese/type II diabetes animals results from an impairment of insulin-stimulated glucose uptake into skeletal muscle. Insulin stimulate the translocation of GLUT4 from intracellular location to the plasma membrane. Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) is implicated in mediation of fusion of GLUT4-containing vesicle with the plasma membrane. Present study investigated regulatory effects of Rhodiola sachalinensis administration and exercise training on the expression of GLUT4 protein and SNAREs protein in skeletal muscles of obese Zucker rats. Experimental animals were randomly assigned into one of five groups ; lean control(LN), obese control(OB), exercise-treated(EXE), Rhodiola sachalinensis-treated(Rho), combine of Rho & EXE (Rho-EXE). All animals of exercise training (EXE, Rho-EXE) performed treadmill running for 8 weeks, and animals of Rho groups (Rho, Rho-EXE) were dosed daily by gastric gavage during the same period. After experiment, blood were taken for analyses of glucose, insulin, and lipids levels. Mitochondrial oxidative enzyme (citrate synthase, CS ; $\beta$-hydroxyacyl-CoA dehydrogenase, $\beta$-HAD) activity were analysed. Skeletal muscles were dissected out for analyses of proteins (GLUT4, VAMP2, syntaxin4, SNAP23). Results are as follows. Exercise and/or Rhodiola sachalinensis administration significantly reduced body weight and improved blood lipids (TG, FFA), and increased insulin sensitivity. Endurance exercise significantly increased the activity of mitochondrial enzymes and the expression of GLUT4 protein, however, administration of Rhodiola sachalinensis did not affect them. The effect of exercise and/or Rhodiola sachalinensis administration on the expression of SNARE proteins was unclear. Our study suggested that improvement insulin sensitivity by exercise and/or Rhodiola sachalinensis administration in obese Zucker rats is independent of expression of SNARE proteins.

• Biomolecules & Therapeutics
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• 제23권4호
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• pp.357-366
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• 2015

Isorhamnetin (3-methylquercetin) is a flavonoid derived from the fruits of certain medicinal plants. This study investigated the photoprotective properties of isorhamnetin against cell damage and apoptosis resulting from excessive ultraviolet (UV) B exposure in human HaCaT keratinocytes. Isorhamnetin eliminated UVB-induced intracellular reactive oxygen species (ROS) and attenuated the oxidative modification of DNA, lipids, and proteins in response to UVB radiation. Moreover, isorhamnetin repressed UVB-facilitated programmed cell death in the keratinocytes, as evidenced by a reduction in apoptotic body formation, and nuclear fragmentation. Additionally, isorhamnetin suppressed the ability of UVB light to trigger mitochondrial dysfunction. Taken together, these results indicate that isorhamnetin has the potential to protect human keratinocytes against UVB-induced cell damage and death.