The effect of lipoxin A4 on E. coli LPS-induced osteoclastogenesis

Abstract

Objectives The objective of the present study was to investigate the effect of lipoxin-type A4 (LXA4) on bacterial-induced osteoclastogenesis. Material and methods Human periodontal ligament cells (PDLCs) in coculture with osteoclast precursors (RAW264.7 cells) were exposed to bacterial stimulation with lipopolysaccharide (LPS) to induce inflammation. After 24 h, cells were treated to 100 ng/ml of LXA4 and 50 ng/ml of forymul peptide receptor 2 (FPR2/ALX) receptor antagonist (Boc-2). After 5 days, osteoclastic resorptive activity was assessed on calcium phosphate (CaP) synthetic bone substitute. Additionally, osteoclastic differentiation was evaluated using tartrate-resistant acid phosphatase (TRAP) staining, TRAP enzymatic activity assay, and on the expression of osteoclast-specific genes. Results We found that stimulation of in the osteoclasts with LPS-stimulated PDLCs induced a significant increase in tartrate-resistant acid phosphatase (TRAP) positive cells, higher resorptive activity, and enhanced expression of specific genes. Meanwhile, LXA4-treatment exhibited strong anti-inflammatory activity, and was able to reverse these inflammatory effects. Conclusions We conclude that (1) PDLCs are a potential target for treating bacterial-induced bone resorption in patients with periodontal disease, and (2) LXA4 is a suitable candidate for such therapy. Clinical relevance The results prove that lipoxins have a protective role in bacterial-induced periodontal inflammation and alveolar bone resorption, which can be translated into a clinical beneficial alterative treatment.

Application of specialized pro‐resolving mediators in periodontitis and peri‐implantitis: a review

“…With respect to bone metabolism, several studies demonstrated the ability of SPMs to prevent bone resorption by inhibiting gene expression. SPMs have been shown to inhibit mRNA expression of osteoclastogenesis promoting transcription factors (i.e., NF‐κB, NFATcl and c‐fos), which normally function to promote osteoclastic differentiation by activating the expression of osteoclast‐specific genes (e.g., TRAP, cathepsin K, and MMP‐9) [16, 121–123]. For instance, RvE1 has been shown to inhibit the expression of osteoclast‐specific genes by decreasing nuclear translocation of transcription factors from the cytoplasm to the nucleus in osteoclast precursor cells in vitro [124].…”

“…Li et al [18] observed that LXA4 inhibited polymethylmethacrylate (PMMA)‐upregulated production of TNFα, IL‐1β, PGE2, and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) in a dose‐dependent manner. Furthermore, LXA4 counteracted RANKL/LPS‐induced formation and function of osteoclasts in an in vitro co‐culture model composed of primary human PDLFs and murine RAW246.7 cell line [123]. LXA4 suppressed RANKL/LPS‐induced upregulation of osteoclast‐associated genes (e.g., RANKL, TRAP, cathepsin K), TRAP activity, and the number of TRAP‐positive cells.…”

High Virulence and Multidrug Resistance of Escherichia coli Isolated in Periodontal Disease

“…Notably, the percentages of biofilm production identified in the strains were comparable to those previously reported in highly pathogenic UPEC strains [ 44 ]. Additionally, it has been suggested that E. coli lipopolysaccharides (LPS) may have a role in the inflammatory processes associated with periodontal disease [ 53 , 54 ].…”

The impacts of oral and gut microbiota on alveolar bone loss in periodontitis

“…[53][54][55] In co-cultures of periodontal ligament cells and osteoclast precursor cells, the addition of LPS increased the number of osteoclasts. 56,57 E. coli LPS stimulates the production of RANKL and prostaglandin E2 (PGE2) through TLR4 in osteoblasts, which promotes the formation of osteoclasts in co-cultures of osteoblasts and bone marrow cells (including osteoclast progenitor cells). 58,59 Similarly, E. coli LPS and Actinomycete LPS increased the expression of RANKL in periodontal ligament cells.…”