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Mithramycin downregulates proinflammatory cytokine-induced matrix metalloproteinase gene expression in articular

Abdelhamid Liacini1, Judith Sylvester, Wen Qing Li

  • 1Département de Médecine and Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CHUM), Hôpital Notre-Dame du CHUM, Montréal, Québec, Canada.

Arthritis Research & Therapy
|July 1, 2005
PubMed

Insights

Mithramycin, an anti-cancer drug, effectively reduces the expression of matrix metalloproteinases (MMPs) in cartilage cells. This finding suggests mithramycin may help prevent cartilage breakdown in conditions like arthritis.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Rheumatology

Background:

  • Proinflammatory cytokines, including Interleukin-1 (IL-1), IL-17, and Tumor Necrosis Factor-alpha (TNF-alpha), drive cartilage degradation in arthritis via matrix metalloproteinases (MMPs).
  • Understanding regulators of MMPs in chondrocytes is crucial for developing therapeutic strategies against joint degeneration.

Purpose of the Study:

  • To investigate the effect of the anti-neoplastic antibiotic mithramycin on the induction of MMPs in chondrocytes.
  • To determine if mithramycin can downregulate MMP expression stimulated by key proinflammatory cytokines.

Main Methods:

  • Mithramycin's impact on MMP-3 and MMP-13 gene expression was assessed in human chondrosarcoma SW1353 cells and primary human and bovine chondrocytes stimulated with IL-1beta, TNF-alpha, and IL-17.
  • MMP-13 levels in cartilage explants were measured under constitutive and IL-1-stimulated conditions.
  • Mitogen-activated protein kinase (MAPK) phosphorylation pathways (ERK, p38, JNK) were analyzed.

Main Results:

  • Mithramycin significantly downregulated MMP-3 and MMP-13 gene expression induced by IL-1beta, TNF-alpha, and IL-17 in all tested cell types.
  • Mithramycin suppressed both constitutive and IL-1-stimulated MMP-13 levels in human and bovine cartilage explants.
  • No significant effect of mithramycin was observed on the phosphorylation of ERK, p38, or JNK.

Conclusions:

  • Mithramycin effectively inhibits the expression of key matrix metalloproteinases (MMPs) in chondrocytes and cartilage explants, independent of MAPK signaling.
  • The findings indicate mithramycin's potential as a therapeutic agent to mitigate cartilage degeneration in arthritic conditions.
  • The precise mechanisms underlying mithramycin's inhibitory effects on MMPs warrant further investigation.

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