Regulation of IFN-gamma induced Inflammatory Response in Rat Brain Astrocytes
Astrocytes에서 IFN-gamma에 의한 염증반응 조절연구
- 주제(키워드) Brain inflammation , JAK/STAT pathway , Lipoxygenases , 뇌 염증반응
- 발행기관 아주대학교 대학원
- 지도교수 Joe, Eun Hye
- 발행년도 2004
- 학위수여년월 2005. 2
- 학위명 석사
- 학과 및 전공 일반대학원 신경과학기술과정
- 본문언어 영어
초록/요약
Janus kinase (JAK) and signal transducers and activators of transcription (STAT) are major pathways that mediate inflammatory functions of interferon-γ (IFN-γ), a prominent pro-inflammatory cytokine. Therefore, it is required to regulate JAK/STAT signaling pathways to modulate IFN-γ-mediated inflammation. In this study, I revealed that nordihydroguaiaretic acid (NDGA), a well known lipoxygenase (LO) inhibitor, suppressed IFN-γ-induced inflammatory responses in brain glial cells. In the presence of NDGA, IFN-γ-induced IRF protein expression and MCP-1 and IP-10 mRNA expression were suppressed. NDGA also suppressed tyrosine-phosphorylation of JAK and STAT. However, the effect of NDGA seemed to be independent of inhibition of 5-LO since none of 5-LO products, leukotriene B4 (LTB₄) and leukotriene C4 (LTC₄), was detected in cells treated with IFN-γ. Other 5-LO inhibitors (Rev5901 and AA861) did not mimic the effect of NDGA. In addition, none of 5-LO metabolites, 5-hydroxyeicosatetraenoic acid (5-HETE) and leukotriene B4 (LTB₄), reversed NDGA-driven suppression of STAT activation or affect basal STAT phosphorylation. Taken together, these results suggest that NDGA regulate IFN-γ-mediated inflammation through the mechanisms unrelated to the inhibition of 5-LO.
more초록/요약
Janus kinase (JAK)과 signal transducers and activators of transcription (STAT)은 중요한 염증성 cytokine인 IFN-gamma의 염증반응을 매개하는 주요한 경로이다. 따라서, JAK/STAT 경로의 조절은 IFN-gamma에 의해 유도되는 염증반응을 조절하는데 중요하다. 본 연구에서 우리는 lipoxygenase (LO) 억제제로 잘 알려져 있는 nordihydroguaiaretic acid (NDGA) 가 뇌신경교세포에서 IFN-gamma에 의해 유도된 염증반응을 억제함을 밝혔다. NDGA가 존재할 때, IFN-gamma에 의해 증가된 interferon regulatory factor-1 (IRF-1) 과 interferon inducing protein-10 (IP-10) 의 발현이 감소하였다. 또한, NDGA는 JAK과 STAT의 tyrosine 인산화를 억제하였다. 그러나, IFN-gamma를 처리한 세포에서 5-LO의 주요한 생성물인 leukotriene B₄ (LTB₄) 와 leukotriene C₄ (LTC₄) 가 생성되지 않고, 다른 5-LO 억제제인 Rev5901과 AA861이 NDGA의 효과를 모방하지 않는 것으로 보아 NDGA의 효과는 5-LO를 억제하는 작용과는 독립적으로 나타나는 효과로 보인다. 게다가, 5-LO의 주요한 대사 산물인 5-hydroxyeicosatetraenoic acid (5-HETE) 와 LTB4가 NDGA에 의한 STAT활성화의 억제를 반전시키지 못했다. 따라서 이러한 결과는 NDGA가 IFN-gamma에 의해 유도되는 염증반응을 조절하는데, 5-LO 억제 기전과는 관계없이 나타나는 현상임을 제시한다.
more목차
TABLE OF CONTENTS
ABSTRACT = i
TABLE OF CONTENTS = ⅱ
LIST OF FIGURES = ⅳ
Ⅰ. INTRODUCTION = 1
Ⅱ. MATERIALS AND METHODS = 5
A. Reagents = 5
B. Preparation of cells = 5
C. Reverse Transcription and Polymerase Chain Reaction (RT-PCR) = 6
D. Western Blot Analysis = 7
E. LTB₄, and LTC₄ Assay = 7
F. Stereotaxic injection of IFN-γ = 8
Ⅲ. RESULTS = 9
A. Nordihydroguaiaretic acid (NDGA) suppressed IFN-γ-induced inflammatory responses in brain glial cells = 9
1. NDGA reduced IFN-γ-induced activation of STAT1 and STAT3 in brain glial cells = 9
2. NDGA reduced IFN-γ-induced JAK2 activation in brain glial cells = 10
3. NDGA reduced IFN-γ-induced IRF-1 and IP-10 expression in brain glial cells = 10
B. NDGA suppressed IFN-γ-induced inflammatory responses in vivo = 14
1. NDGA reduced IFN-γ-mediated inflammatory response in vivo = 14
C. NDGA suppressed IFN-γ-induced STAT phosphorylation independently of lipoxygenase inhibition = 14
1. IFN-γ produced neither LTB4 nor LTC₄ = 14
2. Effect of Rev5901, AA861, baicalein on IFN-γ-induced STAT phosphorylation 15
3. Products of 5-LO did not reverse the inhibitory effect of NDGA = 19
Ⅳ. DISCUSSION = 21
Ⅴ. CONCLUSION = 24
REFERENCES = 25
국문요약 = 34
