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Activation dependent expression of MMPs in peripheral blood mononuclear cells involves protein kinase A

K Saja1, Urmimala Chatterjee, B P Chatterjee

  • 1Department of Biochemistry, University of Kerala, Kariavattom, Thiruvananthapuram, 695 581, Kerala, India.

Molecular and Cellular Biochemistry
|October 18, 2006
PubMed

Insights

Artocarpus lakoocha agglutinin (ALA) significantly upregulates matrix metalloproteinase-9 (MMP-9) in monocytes, offering a novel in vitro model for studying inflammatory signaling pathways. This lectin activates key intracellular signaling cascades, demonstrating its potential in inflammation research.

Area of Science:

  • Immunology
  • Cell Biology
  • Biochemistry

Background:

  • Monocytes/Macrophages are key players in inflammation.
  • Matrix metalloproteinases (MMPs) produced by these cells are critical in inflammatory processes.
  • Understanding monocyte activation and MMP production is vital for inflammation research.

Purpose of the Study:

  • To investigate the activation-dependent upregulation of MMPs in human peripheral blood mononuclear cells (PBMCs) using lectins as an in vitro model.
  • To elucidate the signaling pathways involved in lectin-induced MMP production in monocytes.

Main Methods:

  • Human PBMCs were cultured and treated with various lectins, including Concanavalin A (ConA), Wheat Germ Agglutinin (WGA), and Artocarpus lakoocha agglutinin (ALA).
  • Zymography, ELISA, immunoblot analysis, and RT-PCR were employed to assess MMP production, specifically MMP-9.
  • Indomethacin and Bt(2)cAMP were used to investigate prostaglandin and cAMP pathway involvement, while H-89 was used to study the protein kinase A (PKA) pathway.

Main Results:

  • Monocytes produced minimal MMPs under basal conditions.
  • Lectins, particularly ALA, significantly upregulated MMP production in a concentration- and time-dependent manner.
  • ALA-induced MMP-9 upregulation involved cAMP-dependent signaling, PKA activation, and prostaglandin-mediated effects via cyclooxygenase upregulation.

Conclusions:

  • Artocarpus lakoocha agglutinin (ALA) effectively activates monocytes to upregulate MMP-9 production.
  • The study identified cAMP and PKA as key intracellular mediators in ALA-induced MMP-9 expression.
  • ALA-activated monocytes provide a valuable in vitro model for studying intracellular signaling in inflammatory responses.

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