목차

ABSTRACT i
TABLE OF CONTENTS iv
LIST OF FIGURES vii
LIST OF TABLES x
ABBREVIATION xi
I. INTRODUCTION 1
A. Brain inflammation 1
B. Gangliosides and oxidized low density lipoprotein (oxLDL) 2
1. Gangliosides 2
2. OxLDL 3
C. Inflammatory signaling pathways 7
1. JAK-STAT pathway 7
2. Lipopolysaccharide (LPS) –induced signaling pathways 8
3. Liver X receptor (LXR) pathway as anti-inflammatory signaling Pathway 9
D. Aims of study 10
II. MATERIALS AND METHODS 11
A. Reagents 11
B. Cell culture 12
C. Electrophoresis mobility shift assay (EMSA) 12
D. Reverse transcriptase-polymerase chain reaction (RT-PCR) 13
E. Western blot analysis 15
F. Determination of NO release 15
G. Enzymatic digestion of sialic acid 16
H. Oxidation of LDL 16
I. Relative electrophoretic mobility (REM) assay 16
J. Thiobarbituric acid reacting substances (TBARS) assay 17
K. Lipid hydroperoxide (LPO) assay 17
L. Enzyme-linked immunosorbent assay (ELISA) 17
M. Data analysis 18
III. RESULTS 19
A. JAK-STAT Signaling Mediates Gangliosides-induced Inflammatory Responses in Brain Microglial Cells 19
1. Gangliosides Induce Nuclear Factor Binding to GAS/ISRE Elements 19
2. Gangliosides Induce the Phosphorylation of STAT1 and STAT3 23
3. Gangliosides Induce Phosphorylation and Activation of JAK1 and JAK2 25
4. Gangliosides Stimulate STAT-responsive Inflammatory Gene Expression 28
5. AG490 Reduces Gangliosides-induced Release of NO 28
6. ERK Activity Appears to be Regulated by JAK Activation 30
7. Sialic Acid Residues Are Important for Gangliosides-induced Phosphorylation of STAT 32
B. Oxidized Low Density Lipoprotein (oxLDL) Suppresses Lipopolysaccharide (LPS)–induced Inflammatory Responses in Microglia 38
1. OxLDL Potently Inhibits LPS-induced Expression of iNOS and COX2 in Primary Microglia Cultured from Rat Brain 38
2. OxLDL Suppresses the Expression and Release of Inflammatory Mediators in an Oxidation-dependent Manner 38
3. Inhibitory Effects of OxLDL are Mediated by Interference with LPS-induced NFκB Activation, IFNβ Release, and STAT1 activation in Brain Microglia 49
4. Oxysterol/LXR Agonists Mimic Anti-inflammatory Effects of OxLDL on LPS-activated Microglia 54
IV. DISCUSSION 64
A. JAK-STAT Signaling Mediates Gangliosides-induced Inflammatory Responses in Brain Microglial Cells 64
B. Oxidized Low Density Lipoprotein (oxLDL) Suppresses LPS–induced Inflammatory Responses in Microglia 71
V. CONCLUSION 76
REFERENCES 77
국문요약 98