Astrocytes에 의한 microglia의 염증반응 조절 연구

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dc.description학위논문(석사)--아주대학교 일반대학원 :의학과,2008. 8-
dc.description.abstractMicroglia는 뇌에 존재하는 주요 염증세포로 뇌가 상해를 입으면 활성화되어 여러 가지 염증매개물질들을 생산하며 이러한 염증매개물질들은 뇌 손상을 악화시킬 수 있다. 기존에 발표된 연구에 따르면 astrocyte는 수용성물질을 분비하여 microglia의 과도한 활성화를 억제한다. 하지만, 뇌 손상은 astrocyte에도 영향을 미치므로 본 연구에서는 상해를 입은 astrocytes가 microglia의 활성화를 조절하는 양상을 확인하였다. Astrocytes에 상해를 주기 위해 oxygen-glucose deprivation (OGD) 과 hydrogen peroxide (H₂O₂, 0.01-1 mM)을 각각 처리한 후, 그 배양액(OGD-ACM 또는 H₂O₂-ACM)을 얻었다. OGD-ACM 또는 H₂O₂-ACM는 모두 IFN-γ로 활성화시킨 microglia의 iNOS, COX-2, TNF-α그리고 IL-6 발현을 억제 하였으며, 이러한 효과는 astrocyte가 손상을 받은 후 5분 이내에 나타날 수 있음을 확인하였다. 하지만, OGD를 24시간 처리하여 세포사가 일어난 astrocytes로부터의 OGD-ACM은 IFN-γ에 의한 iNOS 발현을 억제하지 못하였다. OGD-ACM은 IFN-γ에 의해 활성화되는 전사인자인 STAT-1/3의 인산화와 핵으로의 이동을 막지 못하는 반면 STAT의 DNA binding과 GAS-promoter의 활성화를 감소 시켰다. 따라서, OGD-ACM에 의한 microglia의 활성화 억제는 핵 안에서 이루어질 것으로 생각된다. 이러한 결과들은, 상해를 입은 astrocyte가 microglia의 과도한 염증반응을 막음으로써, 염증반응에 의해 유도될 수 있는 신경계의 이차 손상을 억제하는 기전이 될 것으로 생각할 수 있다.-
dc.description.tableofcontentsABSTRACT = i TABLE OF CONTENTS = iii LIST OF FIGURES = v LIST OF TABLES = vi Ⅰ. INTRODUCTION = 1 A. Microglia and brain inflammation = 1 B. Positive and negative regulation of microglial activation = 1 C. Specific aims of this study = 3 Ⅱ. MATERIALS AND METHODS = 5 A. MATERIALS = 5 B. METHODS = 5 1. Cell culture = 5 2. Preparation of OGD-ACM = 6 3. Reverse transcription-PCR = 6 4.Western blot analysis = 7 5.Measurement of NO Release = 8 6.Plasmids = 8 7.Transfection and luciferase assays = 8 8.Nuclear fractionation = 9 9.Live/dead viability assay = 10 Ⅲ. RESULTS = 11 A. Astrocytes treated with oxygen-glucose deprivation (OGD) reduce iNOS expression in IFN-ν-treated BV2 microglia. = 11 B. OGD-ACM reduces expression of pro-inflammatory mediators in primary cultured microglia. = 13 C. The extent of damage determines anti-inflammatory effect of astrocytes. = 15 D. OGD-ACM directly reduces iNOS expression without induction of protein expression. = 19 E. OGD-ACM reduces GAS-promoter activity without inhibition of STAT-1/3 activation. = 21 Ⅳ. DISCUSSION = 26 V. CONCLUSION = 29 REFERENCES = 30 국문요약 = 39-
dc.publisherThe Graduate School, Ajou University-
dc.rights아주대학교 논문은 저작권에 의해 보호받습니다.-
dc.titleAstrocytes에 의한 microglia의 염증반응 조절 연구-
dc.title.alternativeKim, Jong-hyeon-
dc.contributor.affiliation아주대학교 일반대학원-
dc.contributor.alternativeNameKim, Jong-hyeon-
dc.contributor.department일반대학원 의학과- 8-
dc.description.alternativeAbstractMicroglia, the major inflammatory cells in the brain, are activated in injured brain and produce several inflammatory mediators. Previously, it has been reported that soluble factors from cultured astrocytes are capable of suppressing microglial activation. However, brain injury affect not only microglia but astrocytes. Therefore, I examined how astrocytes in injury states modulate microglial activation. Astrocytes were treated with oxygen-glucose deprivation (OGD) or hydrogen peroxide (H₂O₂, 0.01-1 mM), and culture conditioned media (OGDACM or H₂O₂-ACM) were collected. Both OGD-ACM and H₂O₂-ACM collected within 3 h after the treatment strongly reduced iNOS, COX-2, TNF-alpha, and IL-6 in interferon-γ (IFN-γ)-activated microglia. However, OGD-ACM collected from dead astrocytes at 24 h after the treatment did not reduce IFN-γ-induced iNOS expression. OGD-ACM inhibited microglial activation via direct suppression of IFN-γ-signaling without protein synthesis such as HO-1 or SOCS. The target regulated by OGD-ACM appeared to be in the nucleus since OGD-ACM did not inhibit phosphorylation and translocation from the cytosol to the nucleus of STAT 1/3 but reduced GAS-promoter activity. Taken together, these results suggest that astrocytes in injured brain suppress microglial activation to prevent severe inflammation and inflammation-induced secondary damage.-
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Graduate School of Ajou University > Department of Medicine > 3. Theses(Master)
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