The anti-inflammatory action of tetracyclines

  • Christopher R. Dunston

Student thesis: Doctoral ThesisDoctor of Philosophy

Abstract

For six decades tetracyclines have been successfully used for their broad spectrum antibiotic effects. However, non-antibiotic effects of tetracyclines have been reported. The anti-inflammatory effects of tetracycline drugs have been investigated in the context of a range of inflammatory diseases including sepsis and a number of neurodegenerative diseases. This thesis investigates the effects of a range of clinically important tetracyclines (oxytetracycline, doxycycline, minocycline and tigecycline) on the ability of the J774.2 cell line to produce nitric oxide when stimulated with the bacterial cell wall component, LPS. The proteome of J774.2 cells was analysed in response to LPS stimulation (1 µg/ml) with and without prior treatment with minocycline (50µg/ml), this allows the unbiased analysis of the cellular proteome in response to minocycline and LPS, protein spots of interest were excised and identified by nano-electrospray ionisation-linear ion trap mass spectroscopy. All of the tetracyclines that were investigated inhibited LPS-induced nitric oxide production in a dose dependent manner and this was due to the inhibition of inducible nitric oxide synthase expression. This is the first report to show that tigecycline inhibits inducible nitric oxide expression and nitric oxide production. Using two-dimensional gel electrophoresis and total protein staining eleven proteins were identified as being modulated by LPS. Of these eleven proteins; expression of some, but not all was modulated when the cells received a prior treatment with minocycline suggesting that minocycline does not completely block LPS-induced macrophage activation but probably specifically acts on particular inflammatory signaling pathways in macrophages. Three protein spots with a similar molecular weight but different pI values identified in this proteomic study were identified as ATP synthase ß chain.
These different protein spots probably correspond to different phosphorylation states of the protein, suggesting that minocycline affects the balance of protein kinase and protein phosphatase activity in the immune response.
Date of Award2008
Original languageEnglish
SupervisorPeter Lambert (Supervisor), Susan Staddon (Supervisor) & Ann Vernallis (Supervisor)

Keywords

  • nitric oxide
  • minocycline
  • lipopolysaccharide
  • proteomics

Cite this

The anti-inflammatory action of tetracyclines
Dunston, C. R. (Author). 2008

Student thesis: Doctoral ThesisDoctor of Philosophy