LPS Sensing Mechanism of Human Astrocytes: Evidence of Functional TLR4 Expression and Requirement of Soluble CD14.
10.4167/jbv.2017.47.4.189
- Author:
Joo Young PARK
1
;
Kyoung Ho LEE
;
Hyun Sook PARK
;
Sun Ju CHOI
Author Information
1. Department of Microbiology, Institute of Basic Medical Science, Yonsei University, Wonju College of Medicine, Wonju, Gangwon-do, Korea. sun1116@yonsei.ac.kr
- Publication Type:Original Article
- Keywords:
Astrocytes;
Toll-like receptor;
CD14;
LPS
- MeSH:
Astrocytes*;
Central Nervous System;
Culture Media, Serum-Free;
Cytokines;
Electrophoretic Mobility Shift Assay;
Enzyme-Linked Immunosorbent Assay;
Humans*;
Interleukin-8;
Interleukins;
Toll-Like Receptors;
Tumor Necrosis Factor-alpha
- From:Journal of Bacteriology and Virology
2017;47(4):189-198
- CountryRepublic of Korea
- Language:English
-
Abstract:
Among a myriad of pathogen-associated molecular pattern-sensing receptors, toll-like receptors (TLRs) are the principal core sensors of the host. Despite intensive studies for the expression of TLRs and their roles in the central nervous system, controversies remain regarding the expression and the function of TLR4 in human astrocytes. In order to clarify this issue, we attempted to verify functional expression of TLR4 in human astrocytes. Using Reverse transcription-polymerase chain reaction (RT-PCR), we confirmed that the human astrocytes express the TLR4 constitutively. To determine the function of TLR4, astrocytes were treated with TLR4 ligand or lipopolysaccharide (LPS), and then inflammatory cytokines expressions were checked using RT-PCR and enzyme-linked immunosorbent assay. Nuclear factor (NF)-κB activation was checked using electrophoretic mobility shift assay. Treatment of astrocytes with LPS increased tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-8 expression and induced NF-κB activation. Neutralizing anti-TLR4 antibody blocked the effect of LPS on cytokine production and NF-κB activation in astrocytes. The effect of LPS on cytokine production and NF-κB activation was shown in the presence of serum but not in the absence of serum. Therefore, we investigated the sensing mechanism of LPS in human astrocytes. Human astrocytes were treated with LPS following neutralizing anti-CD14 antibody treatment in the presence of serum. Neutralizing anti-CD14 antibody treatment abolished the effect of LPS on cytokine expression and NF-κB activation. Additionally, supplement of recombinant CD14 in serum-free media induced LPS effect on cytokine production and NF-κB activation. In these results, we showed that human astrocytes constitutively express functional TLR4 and require soluble CD14 to recognize LPS.
