• 대한한의학방제학회지
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• 제28권1호
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• pp.15-27
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• 2020

Objectives : We selected three herb-combined remedies, Bigihwan (BGH), Daechilgitang (DCGT) and Mokwhyangbinranghwan (MHBRH), through Donguibogam text-mining analysis, and evaluated their anti-cancer effects on human hepatocellular carcinoma Hep3B cells. Methods : Cytotoxicity was assessed by an MTT assay. Apoptosis rate, autophagy and ROS level were detected by flow cytometry. The autophagy was also observed by Cyto-ID staining fluorescence microscopy. The expression of autophagy, mitophagy and pexophagy regulatory proteins was detected by Western blot analysis. Results : BGH showed the strongest effect among the three prescriptions in inhibiting Hep3B cell viability, which was associated with the induction of apoptosis and autophagy. Autophagy blockers improved cell viability and reduced apoptosis after BGH and DCGT treatments, indicating that autophagy by these prescriptions enhanced Hep3B cells against their cytotoxicity. However, MHBRH enhanced the reduction of cell viability and apoptosis by autophagy blockers. Induction of autophagy by BGH treatment was associated with mitophagy due to mitochondrial dysfunction than DCGT and MHBRH-treated cells. In addition, induction of apoptosis by BGH treatment was ROS-dependent and showed the possibility of pexophagy involvement. Conclusion : Although further studies need to be conducted to study the efficacy and mechanism of accurate anticancer activity, the present results will serve as important sources of understanding the mechanism of action of herbal remedies prescribed for liver disease as documented in Donguibogam.

• International Journal of Oral Biology
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• 제42권3호
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• pp.85-90
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• 2017

Mitochondria participate in various intracellular metabolic pathways such as generating intracellular ATP, synthesizing several essential molecules, regulating calcium homeostasis, and producing the cell's reactive oxygen species (ROS). Emerging studies have demonstrated newly discovered roles of mitochondria, which participate in the regulation of innate immune responses by modulating NLRP3 inflammasomes. Here, we review the recently proposed pathways to be involved in mitochondria-mediated regulation of inflammasome activation and inflammation: 1) mitochondrial ROS, 2) calcium mobilization, 3) nicotinamide adenine dinucleotide ($NAD^+$) reduction, 4) cardiolipin, 5) mitofusin, 6) mitochondrial DNA, 7) mitochondrial antiviral signaling protein. Furthermore, we highlight the significance of mitophagy as a negative regulator of mitochondrial damage and NLRP3 inflammasome activation, as potentially helpful therapeutic approaches which could potentially address uncontrolled inflammation.

• BMB Reports
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• 제51권6호
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• pp.274-279
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• 2018

Mitochondria are crucial organelles that generate cellular energy and metabolites. Recent studies indicate that mitochondria also regulate immunity. In this review, we discuss key roles of mitochondria in immunity against pathogen infection and underlying mechanisms, focusing on discoveries using Caenorhabditis elegans. Various mitochondrial processes, including mitochondrial surveillance mechanisms, mitochondrial unfolded protein response ($UPR^{mt}$), mitophagy, and reactive oxygen species (ROS) production, contribute to immune responses and resistance of C. elegans against pathogens. Biological processes of C. elegans are usually conserved across phyla. Thus, understanding the mechanisms of mitochondria-mediated defense responses in C. elegans may provide insights into similar mechanisms in complex organisms, including mammals.

• 생명과학회지
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• 제30권5호
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• pp.460-467
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• 2020

간암은 전 세계적으로 가장 높게 진단되는 암 중 하나이며, 방사선 및 화학 요법이 일반적으로 사용되는 치료법이지만 다양한 부작용은 치료 효과를 크게 제한한다. 따라서 전통 의학에서 사용되어 온 처방법은 이를 극복할 수 있는 대안이 될 수 있다. 본 연구에서는 동의보감에 기술되어 있는 3가지 한약 처방전(비기환, 대칠기탕 및 목향빈랑환)을 선택하여 인체 간암세포에 대한 항암 효과를 평가하였다. 간암세포에서 3가지 처방전의 에탄올 추출물의 세포 독성을 조사하기 위한 MTT 분석 결과, 비기환 추출물은 대칠기탕 및 목향빈랑환에 비하여 세포 생존력을 현저하게 억제하였다. 그리고, flow cytometry 분석의 결과에서 3가지 처방전 추출물에 의한 간암세포의 증식 억제가 apoptosis 및 autophagy 유도와 관련이 있었다. 특히, 비기환 추출물은 미토콘드리아의 기능을 크게 손상시켰으며 다른 두 처방전과 비교하여 mitophagy 유발 가능성을 보여주었다. 아울러 비기환 추출물은 LC3의 발현을 현저하게 증가시켰으며, 이는 Bcl-2의 발현 감소를 동반하는 반면, Bax의 발현에 영향을 미치지 않았다. PINK1의 발현 또한 비기환 추출물이 처리된 세포에서 매우 증가하였다. 나아가, autophagy 억제제는 3가지 처방전 추출물 처리에 의한 세포 생존율 감소와 apoptosis 유도를 억제하였으며, 이러한 결과는 이들 처방전 추출물 처리에 의한 autophagy가 apoptosis 개시에 관여하고 있음을 보여주는 것이다. 결론적으로, 본 연구 결과는 비기환 추출물이 3가지 처방전 중에서 가장 높은 항암 활성을 보였으며, 비기환 추출물은 autophagy 유도제로서 간암세포의 증식을 억제함을 의미한다.

• 대한임상검사과학회지
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• 제51권2호
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• pp.221-234
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• 2019

암은 유전적, 대사질환적 그리고 감염성 질환 등에 의해 유발되는 생명을 위협하는 심각한 질환으로서, 세포의 성장이 정상적으로 통제되지 않으며, 공격적인 형태로 주변의 조직이나 장기로 침범하는 경향을 보이는 생명을 심각하게 위협하는 질병이다. 지난 수십 년 간, 인류의 건강을 위협하는 암을 정복하기 위한 지속적인 노력이 있었고, 암 신생 기전 및 항암제 연구가 항암제 내성에 대한 연구와 함께 다양한 연구주제로 다루어져 왔다. Hinokitiol (${\beta}$-thujaplicin)은 측백나무과 편백속에 속하는 나무에서 분비되는 terpenoid 물질로서, 항염증작용, 항균작용 및 몇몇 암세포 주에서 autophagy를 통한 항암효과가 있는 것으로 잘 알려져 있다. 본 연구에서는, hinokitiol이 세포 영양상태의 변화유무에 관계없이, transcription factor EB (TFEB)의 핵으로의 이동을 촉진한다는 것을 확인하였다. TFEB의 핵으로의 이동은 autophagy 및 lysosome관련 유전자의 발현을 촉진시키고, 세포질 내에 증가된 autosome과 lysosomal puncta의 관찰을 가능하게 하였다. Hinokitiol를 HCC827세포에 처리한 경우에서, 세포 내 autophagy의 증가와 더불어, mitochondria의 hyper-fragmentation과 mitochondria의 authophagic degradation (mitophagy)가 함께 증가되는 것이 관찰되었다. Hinokitiol은 자궁경부암 세포주인 HeLa세포와 비소세포 폐암 세포주인 HCC827에서 암세포 특이 독성을 나타내었다. 더욱이, TFEB 과발현을 통해 autophagy를 인위적으로 증가시킨 HeLa 세포에서 hinokitiol에 대한 세포독성은 더욱 강화된 것으로 나타났다. 이러한 결과들을 통해, hinokitiol은 TFEB의 핵으로의 이동을 촉발시키는 강력한 autophagy inducer임을 확인할 수 있었다. 본 연구에서 처음으로 확인된 hinokitiol에 의한 TFEB의 활성화 및 비소세포성 암세포에서 항암효과의 상승작용은 다양한 항암제 저항성 세포들에 대한 새로운 치료법 및 대체요법 개발과 관련된 의미 있는 결과로 향후, 분자수준의 작용기작에 대한 추가적인 연구가 수행되어야 할 것으로 사료된다.

• Biomolecules & Therapeutics
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• 제31권1호
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• pp.97-107
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• 2023

Aristolochic acid (AA), extracted from Aristolochiaceae plants, plays an essential role in traditional herbal medicines and is used for different diseases. However, AA has been found to be nephrotoxic and is known to cause aristolochic acid nephropathy (AAN). AA-induced acute kidney injury (AKI) is a syndrome in AAN with a high morbidity that manifests mitochondrial damage as a key part of its pathological progression. Melatonin primarily serves as a mitochondria-targeted antioxidant. However, its mitochondrial protective role in AA-induced AKI is barely reported. In this study, mice were administrated 2.5 mg/kg AA to induce AKI. Melatonin reduced the increase in Upro and Scr and attenuated the necrosis and atrophy of renal proximal tubules in mice exposed to AA. Melatonin suppressed ROS generation, MDA levels and iNOS expression and increased SOD activities in vivo and in vitro. Intriguingly, the in vivo study revealed that melatonin decreased mitochondrial fragmentation in renal proximal tubular cells and increased ATP levels in kidney tissues in response to AA. In vitro, melatonin restored the mitochondrial membrane potential (MMP) in NRK-52E and HK-2 cells and led to an elevation in ATP levels. Confocal immunofluorescence data showed that puncta containing Mito-tracker and GFP-LC3A/B were reduced, thereby impeding the mitophagy of tubular epithelial cells. Furthermore, melatonin decreased LC3A/B-II expression and increased p62 expression. The apoptosis of tubular epithelial cells induced by AA was decreased. Therefore, our findings revealed that melatonin could prevent AA-induced AKI by attenuating mitochondrial damage, which may provide a potential therapeutic method for renal AA toxicity.

• 생명과학회지
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• 제34권1호
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• pp.37-47
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• 2024

Fun14 도메인 함유 단백 1(Fun14 domain-containing protein 1, FUNDC1)은 미토콘드리아 외막에 존재하는 단백질로, 미토콘드리아의 마이토파지(mitophage) 기전 조절에 관여하는 것으로 알려져 있다. 본 연구에서는 해마 뉴런 기원의 HT-22 세포에서 아밀로이드 베타 펩티드(A_β)에 의한 미토콘드리아와 세포 손상 과정에서 FUNDC1의 개재 가능성과 역할을 조사하였다. HT-22 세포에서 A_β를 처리하면 처리 시간에 의존적으로 FUNDC1의 발현 감소가 관찰되었다. 또한 MTT 환원능과 세포 내 ATP 농도, 미토콘드리아 막전압의 감소, 반응성 산소종의 생성과 미토콘드리아 Ca²⁺ 부하의 증가 등 미토콘드리아의 기능적 손상을 나타내는 지표들의 변화와 함께 세포사멸의 증가가 관찰되었다. FUNDC1의 발현을 일시적으로 차단한 세포군에서도 미토콘드리아의 기능적 손상을 나타내는 지표 변화와 세포사멸의 증가가 관찰되었다. 반면에 FUNDC1을 일시적으로 과발현시킨 세포군에서는 A_β 처리에 의한 미토콘드리아 손상과 세포 사멸이 유의하게 억제되었다. 이와 같은 결과들은 A_β에 의한 미토콘드리아와 세포 손상 기전에 FUNDC1이 중요하게 관여할 가능성을 시사한다.

• Molecules and Cells
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• 제46권11호
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• pp.655-663
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• 2023

Autophagy dysfunction is associated with human diseases and conditions including neurodegenerative diseases, metabolic issues, and chronic infections. Additionally, the decline in autophagic activity contributes to tissue and organ dysfunction and aging-related diseases. Several factors, such as down-regulation of autophagy components and activators, oxidative damage, microinflammation, and impaired autophagy flux, are linked to autophagy decline. An autophagy flux impairment (AFI) has been implicated in neurological disorders and in certain other pathological conditions. Here, to enhance our understanding of AFI, we conducted a comprehensive literature review of findings derived from two well-studied cellular stress models: glucose deprivation and replicative senescence. Glucose deprivation is a condition in which cells heavily rely on oxidative phosphorylation for ATP generation. Autophagy is activated, but its flux is hindered at the autolysis step, primarily due to an impairment of lysosomal acidity. Cells undergoing replicative senescence also experience AFI, which is also known to be caused by lysosomal acidity failure. Both glucose deprivation and replicative senescence elevate levels of reactive oxygen species (ROS), affecting lysosomal acidification. Mitochondrial alterations play a crucial role in elevating ROS generation and reducing lysosomal acidity, highlighting their association with autophagy dysfunction and disease conditions. This paper delves into the underlying molecular and cellular pathways of AFI in glucose-deprived cells, providing insights into potential strategies for managing AFI that is driven by lysosomal acidity failure. Furthermore, the investigation on the roles of mitochondrial dysfunction sheds light on the potential effectiveness of modulating mitochondrial function to overcome AFI, offering new possibilities for therapeutic interventions.

• Toxicological Research
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• 제33권3호
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• pp.205-209
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• 2017

Transmembrane Protein 39A (TMEM39A) is a member of TMEM family. The understanding about this protein is still limited. The earlier studies indicated that TMEM39A was a key mediator of autoimmune disease. TMEM39A seems to be involved in systemic lupus erythematosus and multiple sclerosis in numerous of populations. All of these works stop at insufficient information by using gene functioning methods such as: Genome-wide association studies (GWASs) and/or follow-up study. It is the fact that the less understood of TMEM39A actually is the attraction to the scientist in near future. In this review the current knowledge about TMEM39A and its possible roles in cell biology, physiology and pathology will be described.

• Biomolecules & Therapeutics
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• 제27권6호
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• pp.530-539
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• 2019

Brain aging is an inevitable process characterized by structural and functional changes and is a major risk factor for neurodegenerative diseases. Most brain aging studies are focused on neurons and less on astrocytes which are the most abundant cells in the brain known to be in charge of various functions including the maintenance of brain physical formation, ion homeostasis, and secretion of various extracellular matrix proteins. Altered mitochondrial dynamics, defective mitophagy or mitochondrial damages are causative factors of mitochondrial dysfunction, which is linked to age-related disorders. Etoposide is an anti-cancer reagent which can induce DNA stress and cellular senescence of cancer cell lines. In this study, we investigated whether etoposide induces senescence and functional alterations in cultured rat astrocytes. Senescence-associated ${\beta}$-galactosidase (SA-${\beta}$-gal) activity was used as a cellular senescence marker. The results indicated that etoposide-treated astrocytes showed cellular senescence phenotypes including increased SA-${\beta}$-gal-positive cells number, increased nuclear size and increased senescence-associated secretory phenotypes (SASP) such as IL-6. We also observed a decreased expression of cell cycle markers, including PhosphoHistone H3/Histone H3 and CDK2, and dysregulation of cellular functions based on wound-healing, neuronal protection, and phagocytosis assays. Finally, mitochondrial dysfunction was noted through the determination of mitochondrial membrane potential using tetramethylrhodamine methyl ester (TMRM) and the measurement of mitochondrial oxygen consumption rate (OCR). These data suggest that etoposide can induce cellular senescence and mitochondrial dysfunction in astrocytes which may have implications in brain aging and neurodegenerative conditions.