Macrophage Inflammatory Protein-2 in High Mobility Group Box 1 Secretion of Macrophage Cells Exposed to Lipopolysaccharide.

Abstract

BACKGROUND/AIMS:

Macrophage inflammatory protein-2 (MIP-2), a type of leukocyte chemokine, is primarily produced by macrophages, and levels increase significantly in early inflammation. However, the precise biological functions and mechanisms of MIP-2 in the development of inflammation remain unclear. The purposes of the present study were to investigate the role of MIP-2 in inflammation induced by lipopolysaccharide (LPS) in vitro and to determine the possibility of blocking the high mobility group box 1 (HMGB1) signalling pathway via MIP-2 inhibition.

METHODS:

Macrophage cells (RAW264.7, U937 and THP-1 cells) were divided into control and treatments groups. Expression levels of interleukin-6 (IL-6), interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α), HMGB1, chemokine (C-C motif) ligand-2 (Ccl-2), Toll-like receptor-4 (TLR-4), inducible nitric oxide synthase (iNOS), phosphorylated MAPKs (p38, ERKs, JNKs), PI3K/Akts, JAKs/STAT3, IκB, and cytoplasmic and nuclear NF-κB p65 in RAW264.7 cells were detected by qRT-PCR, enzyme-linked immunosorbent assay (ELISA) or western blot assays.

RESULTS:

mip-2 siRNA and an anti-MIP-2 antibody significantly reduced the expression levels of Ccl-2, TLR-4, iNOS, IL-6, IL-1β, HMGB1, and TNF-α in RAW264.7 cells exposed to LPS (P<0.01). Additionally, mRNA expression levels of HMGB1 and TLR-4 in cells treated with LPS+mip-2 siRNA were significantly lower than those in cells treated with LPS alone (P<0.01 or P<0.05). The MIP-2 antibody significantly suppressed activation of p38-MAPK, p-STAT3, and p-Akts and translocation of NF-κB p65 from the cytoplasm to the nucleus in RAW264.7 exposed to LPS (P<0.01 or P<0.05).

CONCLUSION:

mip-2 siRNA and the MIP-2 antibody can reduce the inflammatory effects induced by LPS in macrophage cells. The mechanisms may occur through down-regulation of p38-MAPK, STAT3 and Akts phosphorylation and translocation of NF-κB p65. MIP-2 plays an important role in inflammation induced by LPS.

• Authors: Qin Chaochao, Guohua Lou, Ying Yang, Yanning Liu, Ying Hu, Zheng Min, Ping Chen, Jiliang He, Zhi Chen
• Journal: Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology (Cell Physiol Biochem) Vol. 42 Issue 3 Pg. 913-928 ( 2017) ISSN: 1421-9778 [Electronic] Germany
• PMID: 28662496 (Publication Type: Journal Article)
• Copyright: © 2017 The Author(s). Published by S. Karger AG, Basel.

Chemical References

• Chemokine CXCL2
• HMGB1 Protein
• HMGB1 protein, mouse
• Interleukin-1beta
• Interleukin-6
• Lipopolysaccharides
• RNA, Small Interfering
• Toll-Like Receptor 4
• Tumor Necrosis Factor-alpha
• Nitric Oxide Synthase Type II

Topics

• Animals
• Chemokine CXCL2 (genetics, immunology)
• Down-Regulation
• Gene Expression Regulation
• HMGB1 Protein (genetics, immunology)
• Inflammation (genetics, immunology)
• Interleukin-1beta (genetics)
• Interleukin-6 (genetics)
• Lipopolysaccharides (immunology)
• Macrophages (immunology, metabolism)
• Mice
• Nitric Oxide Synthase Type II (genetics)
• RAW 264.7 Cells
• RNA Interference
• RNA, Small Interfering (genetics)
• Toll-Like Receptor 4 (genetics)
• Tumor Necrosis Factor-alpha (genetics)