Etoposide Induces Mitochondrial Dysfunction and Cellular Senescence in Primary Cultured Rat Astrocytes

( Minji Bang ),( Do Gyeong Kim ),( Edson Luck Gonzales ),( Kyoung Ja Kwon ),( Chan Young Shin ) 한국응용약물학회 2019 Biomolecules & Therapeutics(구 응용약물학회지) Vol.27 No.6

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 β-galactosidase (SA-β-gal) activity was used as a cellular senescence marker. The results indicated that etoposide-treated astrocytes showed cellular senescence phenotypes including increased SA-β-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 Phospho- Histone 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.

Minoxidil Regulates Aging-Like Phenotypes in Rat Cortical Astrocytes In Vitro

Bang Minji,Yang Seung Jin,Ahn TaeJin,Han Seol-Heui,Shin Chan Young,Kwon Kyoung Ja 한국응용약물학회 2023 Biomolecules & Therapeutics(구 응용약물학회지) Vol.31 No.1

Mainly due to the slanted focus on the mechanism and regulation of neuronal aging, research on astrocyte aging and its modulation during brain aging is scarce. In this study, we established aged astrocyte culture model by long-term culturing. Cellular senescence was confirmed through SA-β-gal staining as well as through the examination of morphological, molecular, and functional markers. RNA sequencing and functional analysis of astrocytes were performed to further investigate the detailed characteristics of the aged astrocyte model. Along with aged phenotypes, decreased astrocytic proliferation, migration, mitochondrial energetic function and support for neuronal survival and differentiation has been observed in aged astrocytes. In addition, increased expression of cytokines and chemokine-related factors including plasminogen activator inhibitor -1 (PAI-1) was observed in aged astrocytes. Using the RNA sequencing results, we searched potential drugs that can normalize the dysregulated gene expression pattern observed in long-term cultured aged astrocytes. Among several candidates, minoxidil, a pyrimidine-derived anti-hypertensive and anti-pattern hair loss drug, normalized the increased number of SA-β-gal positive cells and nuclear size in aged astrocytes. In addition, minoxidil restored up-regulated activity of PAI-1 and increased mitochondrial superoxide production in aged astrocytes. We concluded that long term culture of astrocytes can be used as a reliable model for the study of astrocyte senescence and minoxidil can be a plausible candidate for the regulation of brain aging.

Late Passage Cultivation Induces Aged Astrocyte Phenotypes in Rat Primary Cultured Cells

( Minji Bang ),( Edson Luck Gonzales ),( Chan Young Shin ),( Kyoung Ja Kwon ) 한국응용약물학회 2021 Biomolecules & Therapeutics(구 응용약물학회지) Vol.29 No.2

Astrocytes play various important roles such as maintaining brain homeostasis, supporting neurons, and secreting inflammatory mediators to protect the brain cells. In aged subjects, astrocytes show diversely changed phenotypes and dysfunctions. But, the study of aged astrocytes or astrocytes from aged subjects is not yet sufficient to provide a comprehensive understanding of their important processes in the regulation of brain function. In this study, we induced an in vitro aged astrocyte model through late passage cultivation of rat primary cultured astrocytes. Astrocytes were cultured until passage 7 (P7) as late passage astrocytes and compared with passage 1 (P1) astrocytes as early passage astrocytes to confirm the differences in phenotypes and the effects of serial passage. In this study, we confirmed the morphological, molecular, and functional changes of late passage astrocytes showing aging phenotypes through SA-β-gal staining and measurement of nuclear size. We also observed a reduced expression of inflammatory mediators including IL-1β, IL-6, TNFα, iNOS, and COX2, as well as dysregulation of wound-healing, phagocytosis, and mitochondrial functions such as mitochondrial membrane potential and mitochondrial oxygen consumption rate. Cultureconditioned media obtained from P1 astrocytes promoted neurite outgrowth in immature primary cultures of rat cortices, which is significantly reduced when we treated the immature neurons with the culture media obtained from P7 astrocytes. These results suggest that late passage astrocytes show senescent astrocyte phenotypes with functional defects, which makes it a suitable model for the study of the role of astrocyte senescence on the modulation of normal and pathological brain aging.

UNDERSTANDING ULTRA-HIGH RISK FOR PSYCHOSIS

Minji Bang(방민지) 대한소아청소년정신의학회 2018 대한소아청소년정신의학회 학술대회논문집 Vol.2018 No.5

Differences in Functional Level and Central Symptom of Network Structures in the Patients Seeking Treatment for Panic Disorder Before and During the COVID-19 Pandemic

Hyun-Ju Kim(Hyun-Ju Kim),Minji Bang(Minji Bang),Chun Il Park(Chun Il Park),Chongwon Pae(Chongwon Pae),Sang-Hyuk Lee(Sang-Hyuk Lee) 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.3

Objective Mental health problems such as anxiety, panic, and depression have been exacerbated by the coronavirus disease-2019 (COVID-19). This study aimed to compare the symptom severities and overall function before and during the COVID-19 pandemic among patients with panic disorder (PD) seeking treatment compared to healthy controls (HCs). Methods Baseline data were collected from the two groups (patients with PD and HCs) in two separate periods: before COVID-19 (Jan 2016-Dec 2019) and during COVID-19 (Mar 2020-Jul 2022). A total 453 participants (before COVID-19: 246 [139 patients with PD and 107 HCs], during COVID-19: 207 [86 patients with PD and 121 HCs]) was included. Scales for panic and depressive symptoms and overall function were administered. Additionally, network analyses were performed to compare the two groups within the patients with PD. Results The results of two-way analysis of variance analyses showed that patients with PD enrolled during COVID-19 showed higher levels of interoceptive fear and lower overall functioning. In addition, a network comparison test revealed that a significantly high strength and expected influence for agoraphobia and avoidance in patients with PD during COVID-19. Conclusion This study suggested that the overall function could have worsened, and the importance of agoraphobia and avoidance as a central symptom may have increased in patients with PD seeking treatment during COVID-19.

Electrical Properties of CNT and Carbon Fiber Filled Hybrid Composites Based on PA66

( Minji Lee ),( Se-ho Park ),( Kwang-hwan Jhee ),( Hyoungsan Kye ),( Daesuk Bang ) 한국고무학회 2021 엘라스토머 및 콤포지트 Vol.56 No.2

In recent times, the demand for electronic devices has increased because of advancements in the electronics industry. Consequently, research on shielding against electromagnetic interference (EMI) from electronic devices has also progressed significantly. In particular, research on imparting electrical conductivity to plastic has seen substantial progress. In this study, the effect of hybrid fillers comprising carbon fiber (CF) and carbon nanotubes (CNTs) on the electrical properties of polyamide 66 (PA66) composites was investigated. PA66 composites were prepared using a BUSS Co-Kneader single-screw extruder. EMI shielding effectiveness (SE) increased with the increasing addition of unsized CF (UCF), sized CF (SCF), and CNTs. For the PA66/SCF/CNT hybrid filler composites, EMI SE significantly increased with the increase in SCF content. Finally, the hybrid filler comprising SCF and CNTs may have a synergistic effect on the EMI SE and surface resistivity of PA66/SCF/CNT composites.

여대생의 인유두종 바이러스 예방접종 여부에 영향을 미치는 요인

방경숙(Bang Kyung-Sook),성수미(Sung Sumi),구보연(Koo Boyeon),김민지(Kim Minji),김유나(Kim Yuna),김진숙(Kim Jinsook),류수미(Ryu Sumi) 대한종양간호학회 2011 Asian Oncology Nursing Vol.11 No.3

Purpose: The primary prevention for cervical cancer the human papilloma virus (HPV) vaccination has been available in South Korea and its importance has been emphasized publicly. The purpose of this study was to investigate the knowledge regarding HPV vaccination and identify the factors associated with HPV vaccination in female university students. Methods: A sample of 200 women among university students in Seoul was asked to answer a questionnaire on HPV-related knowledge and attitude and influencing factors on HPV vaccination. Results: Among the respondents 12.0% were HPV vaccinated. Overall HPV-related knowledge was low and knowledge was not different between the vaccinated and unvaccinated groups. The vaccinated group demonstrated a higher score on the knowledge about the place where people could receive HPV vaccination and the cost of the vaccination than that of the unvaccinated group. The major influencing factor on vaccination was the parent's recommendation and the major barrier for vaccination was the cost of the vaccination. Conclusion: A broadened public campaign is recommended to increase the knowledge and positive attitude towards HPV vaccination for university female students as well as their parents.

실습 스트레스 및 실습 만족도, 임상수행능력의 차이

황민지 ( Minji Hwang ),방요순 ( Yosoon Bang ) 사단법인 아시아문화학술원 2021 인문사회 21 Vol.12 No.5

본 연구의 목적은 COVID-19 상황에서 교내실습 경험한 작업치료대학생과 임상실습을 경험한 작업치료대학생의 실습 스트레스 및 실습 만족도, 임상수행능력의 차이를 파악하는 것이다. 2021년 8월 23일부터 9월 15일까지 작업치료대학생 83명에게 설문지를 이용하여 자료를 수집하였고, 수집된 자료는 SPSS 24.0을 이용하여 분석하였다. 연구결과, 실습 스트레스는 임상실습을 경험한 작업치료대학생이 유의미하게 높았고, 실습 만족도는 교내실습을 경험한 작업치료대학생이 유의미하게 높았다. 임상수행능력은 임상실습을 경험한 작업치료대학생이 유의미하게 높았다. 이에 본 연구결과를 바탕으로 COVID-19와 같은 전염성 질환에 대비한 대면, 비대면, 교내, 임상 등 다양한 방법의 실습 프로그램의 개발과 학습방법에 대한 연구가 추가적으로 필요할 것으로 본다. This study investigated the differences in practice stress, practice satisfaction, and clinical competence between occupational therapy students who experienced school practice and those who experienced clinical practice during the COVID-19 pandemic. Data were collected using survey questionnaires received from 83 occupational therapy students in Aug. 23 to Sept. 15, 2021 and then analyzed using SPSS 24.0. Research results showed that the occupational therapy students who experienced clinical practice had statistically significantly higher practice stress and clinical competence, whereas those who experienced school practice had statistically significantly higher practice satisfaction. Based on the findings of this study, further research is necessary on the development of various practice programs and learning methods, including face-to-face, non-contact, intramural, and clinical practices, in preparation for infectious diseases such as COVID-19.

Effects of Peroxides on the Properties of Reclaimed Polypropylene/Waste Ground Rubber Tire Composites Prepared by a Twin Screw Extrusion

( Seonggil Kim ),( Minji Lee ),( Hyeongsu Lee ),( Hobin Jeong ),( Yuri Park ),( Kwang Hwan Jhee ),( Daesuk Bang ) 한국고무학회 2016 엘라스토머 및 콤포지트 Vol.51 No.1

In this study, the reclaimed polypropylene (RPP) and waste ground rubber tire (WGRT) were used to simulate the thermoplastic vulcanizate (TPV) for cost reduction and resources recycling. Also, we examined the effects of dicumyl peroxide (DCP) and 2,5-dimethyl-2,5-di-(tert-butylperoxy)-hexane (DTBPH) as peroxide type cross-linking agents to enhance the properties of TPV`s. The components of RPP and WGRT were fixed at 30 and 70 wt%, and DCP and DTBPH were added in the concentrations from 0.5 to 1.5 phr, respectively. RPP/WGRT composites with different contents of DCP and DTBPH were prepared by a modular intermeshing co-rotating twin screw extruder. The Young`s modulus of composites were decreased with increasing peroxides contents. On the other hand, tensile strength, elongation at break, and impact strength of the composites were increased with peroxide contents. We also confirmed that interfacial adhesion between RPP and WGRT was considerably improved by adding the peroxides. Taken together, DTBPH added RPP/WGRT composites exhibited better mechanical properties rather than those of DCP added composites.

Anti-inflammatory Strategies for Schizophrenia: A Review of Evidence for Therapeutic Applications and Drug Repurposing

Jonghee Hong,Minji Bang 대한정신약물학회 2020 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.18 No.1

Schizophrenia is a debilitating psychiatric disorder with a substantial socioeconomic and humanistic burden. Currently available treatment strategies mostly rely on antipsychotic drugs, which block dopaminergic effects in the mesolimbic pathway of the brain. Although antipsychotic drugs help relieve psychotic symptoms, a definitive cure for schizophrenia has yet to be achieved. Recent advances in neuroinflammation research suggest that proinflammatory processes in the brain could cause alterations in neurobehavioral development and increase vulnerability to schizophrenia. With a growing need for novel strategies in the treatment of schizophrenia, it would be meaningful to review the current evidence supporting the therapeutic potential of anti-inflammatory strategies. This review details the key findings of clinical trials that investigate the efficacy of anti-inflammatory agents as adjuvants to antipsychotic treatment. We further discuss the possibilities of repurposing anti-inflammatory agents and developing novel strategies for the treatment of schizophrenia.