Lipocalin 2 inhibits the expressions of interleukin-8 and macrophage inflammatory protein-1α in human neutrophil-like cells.

OBJECTIVES

Lipocalin 2 (LCN2) is a glycoprotein with multiple functions, including antimicrobial activity, inflammatory response modulation, and cell migration. LCN2 is expressed in some cells, such as epithelial cells and neutrophils, and its levels are increased in inflammatory diseases. This study investigated the presence of LCN2 receptor (24p3R) in cells around periodontal tissues and function of LCN2 in cells with a receptor to explore the role of LCN2 in periodontal diseases.

METHODS

The presence of 24p3R was examined in periodontal cells, including human gingival fibroblasts, periodontal ligament fibroblasts, human oral epithelial cells (HOECs), and neutrophil-like cells (HL-60), by Western blotting. Changes in periodontal disease-associated proteins in the presence of recombinant LCN2 (rLCN2) were examined using a protein array in differentiated HL-60 (dHL-60) cells. Interleukin-8 (IL-8) and macrophage inflammatory protein-1α (MIP-1α) mRNA expressions were analyzed by qRT-PCR, and IL-8 and MIP-1α levels in dHL-60 cells treated with rLCN2 or Porphyromonas gingivalis-lipopolysaccaharide (P.g-LPS) were determined by enzyme-linked immunosorbent assay.

RESULTS

We detected 24p3R in dHL-60 cells. IL-8 was highly expressed and MIP-1α was weakly expressed in dHL-60 cells using a protein array. rLCN2 significantly decreased IL-8 mRNA and protein levels and suppressed P.g-LPS-induced IL-8 production in dHL-60 cells. As dHL-60 cells were co-cultured with HOECs in which LCN2 was knocked down, IL-8 mRNA expression increased in dHL-60 cells. Furthermore, rLCN2 inhibited MIP-1α production in dHL-60 cells.

CONCLUSION

LCN2 suppresses inflammatory responses by regulating IL-8 and MIP-1α expression in periodontal diseases.