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Involvement of 15-lipoxygenase in the inflammatory arthritis

Ming-Yueh Wu1, Tzu-Hung Lin, Yung-Cheng Chiu

  • 1Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.

Journal of Cellular Biochemistry
|May 11, 2012
PubMed

Insights

15-Lipoxygenase (15-LOX) drives inflammatory arthritis by increasing matrix metalloproteinase-2 (MMP-2) expression. Inhibiting 15-LOX shows therapeutic potential for inflammatory arthritis treatment.

Area of Science:

  • Biochemistry
  • Immunology
  • Pathology

Background:

  • 15-Lipoxygenase (15-LOX) is implicated in various pathological processes.
  • Matrix metalloproteinases (MMPs), particularly MMP-2, are key enzymes in tissue remodeling and inflammation.
  • Inflammatory arthritis involves complex cellular and molecular pathways contributing to joint destruction.

Purpose of the Study:

  • To investigate the role of 15-LOX in matrix metalloproteinase (MMP) expression within the context of inflammatory arthritis.
  • To elucidate the signaling pathways influenced by 15-LOX and its downstream products in rheumatoid arthritis synovial fibroblasts (RASF).
  • To evaluate the therapeutic potential of targeting 15-LOX in an experimental arthritis model.

Main Methods:

  • Treatment of RASF with 15-(S)-HETE, a 15-LOX product, and assessment of MMP-2 mRNA and protein levels.
  • Inhibition studies using PI3K (LY294002) and NF-κB (PDTC) inhibitors to analyze signaling pathways.
  • Analysis of AKT phosphorylation, p65 nuclear translocation, and IκBα degradation following 15-(S)-HETE treatment.
  • Investigating the effects of TNF-α and IL-1β on MMP-2 and 15-LOX expression in RASF.
  • Evaluating the impact of 15-LOX inhibition (PD146176) and knockdown on cytokine-induced MMP-2 activity.
  • Assessing the efficacy of glucocorticoids and NSAIDs on 15-(S)-HETE-induced MMP-2 expression.
  • Comparing adjuvant-induced arthritis and synovial MMP-2 expression in 15-LOX knockout (KO) mice versus wild-type controls.

Main Results:

  • 15-(S)-HETE significantly increased MMP-2 mRNA and protein levels in RASF.
  • The effects of 15-(S)-HETE were mediated through PI3K/AKT and NF-κB signaling pathways.
  • TNF-α and IL-1β upregulated both 15-LOX expression and MMP-2 activity in RASF.
  • Glucocorticoids, but not NSAIDs, inhibited 15-(S)-HETE-induced MMP-2 expression.
  • 15-LOX deficiency markedly reduced arthritis severity and MMP-2 expression in a mouse model.

Conclusions:

  • 15-LOX plays a critical role in the pathogenesis of inflammatory arthritis, partly through regulating MMP-2 expression.
  • The inflammatory cytokines TNF-α and IL-1β contribute to arthritis by upregulating 15-LOX.
  • Targeting 15-LOX represents a promising therapeutic strategy for managing inflammatory arthritis.

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