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A11-positive β-amyloid Oligomer Preparation and Assessment Using Dot Blotting Analysis
Published on: May 22, 2018
Epigallocatechin gallate attenuates amyloid β-induced inflammation and neurotoxicity in EOC 13.31 microglia
James Cheng-Chung Wei1, Hsiu-Chen Huang2, Wei-Jen Chen3
1Division of Allergy, Immunology and Rheumatology, Chung Shan Medical University Hospital, Taichung, Taiwan; Institute of Integrative Medicine, China Medical University, Taichung, Taiwan; Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan.
Abstract:
Microglia are the primary immune cells that contribute to neuroinflammation by releasing various proinflammatory cytokines and neurotoxins in the brain. Microglia-mediated neuroinflammation is one of the key characteristics of Alzheimer's disease (AD). Therefore, inhibitory reagents that prevent microglial activation may be used as potential therapeutic agents for treating AD. Recently, many studies have been performed to determine the bioactivities of green tea polyphenol epigallocatechin-3-gallate (EGCG), an efficient antioxidant that prevents neuroinflammation. However, limited information is available on the effects of EGCG on microglia-mediated neuroinflammation. In this study, we investigated the inhibitory effects of EGCG on amyloid β (Aβ)-induced microglial activation and neurotoxicity. Our results indicated that EGCG significantly suppressed the expression of tumor necrosis factor α (TNFα), interleukin-1β, interleukin-6, and inducible nitric oxide synthase (iNOS) in Aβ-stimulated EOC 13.31 microglia. EGCG also restored the levels of intracellular antioxidants nuclear erythroid-2 related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), thus inhibiting reactive oxygen species-induced nuclear factor-κB (NF-κB) activation after Aβ treatment. Furthermore, EGCG effectively protected neuro-2a neuronal cells from Aβ-mediated, microglia-induced cytotoxicity by inhibiting mitogen-activated protein kinase-dependent, Aβ-induced release of TNFα. Taken together, our findings suggested that EGCG suppressed Aβ-induced neuroinflammatory response of microglia and protected against indirect neurotoxicity. These results suggest that EGCG is a possible therapeutic agent for preventing Aβ-induced inflammatory neurodegeneration.
Insights
Epigallocatechin-3-gallate (EGCG) from green tea suppresses amyloid-beta-induced microglial activation and neuroinflammation, offering potential for Alzheimer's disease treatment.
Area of Science:
- Neuroscience
- Immunology
- Pharmacology
Background:
- Microglia are key immune cells in the brain, contributing to neuroinflammation and Alzheimer's disease (AD) pathogenesis through cytokine release.
- Microglia-mediated neuroinflammation is a hallmark of AD, making inhibitors of microglial activation potential therapeutic agents.
- Epigallocatechin-3-gallate (EGCG), a green tea polyphenol, is known for its antioxidant and anti-neuroinflammatory properties, but its specific effects on microglia in AD are not fully understood.
Purpose of the Study:
- To investigate the inhibitory effects of EGCG on amyloid-beta (Aβ)-induced microglial activation and associated neurotoxicity.
- To elucidate the molecular mechanisms underlying EGCG's protective effects against Aβ-induced inflammatory responses in microglia.
Main Methods:
- Utilized EOC 13.31 microglia cell models stimulated with Aβ to mimic AD-related neuroinflammation.
- Assessed the expression of key pro-inflammatory mediators such as TNFα, IL-1β, IL-6, and iNOS.
- Measured the levels of intracellular antioxidants Nrf2 and HO-1, and evaluated the activation of NF-κB and MAPK signaling pathways.
- Examined the protective effects of EGCG on neuro-2a neuronal cells against Aβ-mediated, microglia-induced cytotoxicity.
Main Results:
- EGCG significantly suppressed the Aβ-induced expression of pro-inflammatory cytokines (TNFα, IL-1β, IL-6) and iNOS in microglia.
- EGCG restored intracellular antioxidant levels (Nrf2, HO-1) and inhibited Aβ-induced NF-κB activation by reducing reactive oxygen species.
- EGCG protected neuronal cells from Aβ-mediated, microglia-induced cytotoxicity by inhibiting MAPK-dependent TNFα release.
Conclusions:
- EGCG effectively suppresses Aβ-induced microglial activation and neuroinflammation.
- EGCG demonstrates neuroprotective effects against Aβ-induced toxicity by modulating inflammatory and oxidative stress pathways.
- EGCG holds promise as a potential therapeutic agent for preventing Aβ-induced inflammatory neurodegeneration in Alzheimer's disease.
