Highly electronegative low-density lipoprotein L5 evokes microglial activation and creates a neuroinflammatory stress via Toll-like receptor 4 signaling
| Autor: | Liang-En Yu, Jiz-Yuh Wang, Ching-Tien Lee, Chiou-Lian Lai |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Cell Survival Nitric Oxide Synthase Type II Biology Biochemistry 03 medical and health sciences Cellular and Molecular Neuroscience Phosphatidylinositol 3-Kinases 0302 clinical medicine Animals Humans Viability assay Protein kinase B PI3K/AKT/mTOR pathway Neuroinflammation Inflammation Toll-like receptor N2a cell Coculture Techniques Cell biology Interleukin-10 Lipoproteins LDL Toll-Like Receptor 4 030104 developmental biology Cyclooxygenase 2 Immunology Microglia Signal transduction Cell activation Reactive Oxygen Species 030217 neurology & neurosurgery Signal Transduction |
| Zdroj: | Journal of neurochemistry. 142(2) |
| ISSN: | 1471-4159 |
| Popis: | Atherogenic risk factors, such as hypercholesterolemia, are associated with increased risk of neurodegeneration, especially Alzheimer's dementia. Human plasma electronegative low-density lipoprotein [LDL(-)], especially L5, may serve as an important contributing factor. L5 promoting an inflammatory action in atherosclerosis has been extensively studied. However, the role of L5 in inducing neuroinflammation remains unknown. Here, we examined the impact of L5 on immune activation and cell viability in cultured BV-2 microglia. BV-2 cells treated with lipopolysaccharide or human LDLs (L1, L5, or oxLDL) were subjected to molecular/biochemical assays for measuring microglial activation, levels of inflammatory factors, and cell survival. A transwell BV-2/N2a co-culture was used to assess N2a cell viability following BV-2 cell exposure to L5. We found that L5 enables the activation of microglia and elicits an inflammatory response, as evidenced by increased oxygen/nitrogen free radicals (nitric oxide, reactive oxygen species, and peroxides), elevated tumor necrosis factor-α levels, decreased basal interleukin-10 levels, and augmented production of pro-inflammatory proteins (inducible nitric oxide synthase and cyclooxygenase-2). L5 also triggered BV-2 cell death primarily via apoptosis. These effects were markedly disrupted by the application of signaling pathway inhibitors, thus demonstrating that L5 interacts with Toll-like receptor 4 to modulate multiple pathways, including MAPKs, PI3K/Akt, and NF-κB. Decreased N2a cell viability in a transwell co-culture was mainly ascribed to L5-induced BV-2 cell activation. Together, our data suggest that L5 creates a neuroinflammatory stress via microglial Toll-like receptor 4, thereby leading to the death of BV-2 microglia and coexistent N2a cells. Atherogenic L5 possibly contributes to neuroinflammation-related neurodegeneration. |
| Databáze: | OpenAIRE |
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