Novel mechanism of FTY720 identified
 

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Novel mechanism of action of new drug for MS identified
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Virginia Commonwealth University researchers have identified a unique mechanism of action of a new drug that shows great promise for the treatment of multiple sclerosis.

The researchers report the unique action of FTY720, or Fingolimod, an immunosuppressant drug that was already known to affect the functioning of the immune system by preventing the egress of white blood cells from the lymph nodes into the blood. The article was pre-published as a First Edition Paper in Blood, The Journal of the American Society of Hematology, which appeared online on Sept. 28.

In this study, the research team observed that FTY720 also inhibited the activity of a key enzyme called cPLA2, which is necessary for the production of inflammatory mediators, known as eicosanoids. Eicosanoids drive inflammatory disorders such as asthma and multiple sclerosis.

According to Sarah Spiegel, Ph.D., professor and chair in the VCU Department of Biochemistry, and lead author on the study, the inhibition of cPLA2 would shut down the entire inflammatory pathway, possibly without the side-effects caused by medications such as Vioxx, that have been withdrawn from the pharmaceutical market.

FTY720, a drug developed by Novartis, has shown considerable therapeutic effects in a recent small, placebo-controlled clinical trial involving patients with relapsing multiple sclerosis. The study was published in the September 2006 issue of the New England Journal of Medicine by an international research team. With its novel mode of action and the added benefit of an oral formulation, further clinical development of FTY720 might have a major impact on treatment of MS, said Spiegel.

"By clearly understanding the mechanism of action of drugs such as FTY720, we can develop more optimal treatments for inflammatory disease such as asthma or MS. This drug may prevent both inflammation and axonal damage, including demyelination, which are characteristic of MS," said Spiegel.

Source: Virginia Commonwealth University

http://www.physorg.com/news79805704.html

Blood. 2006 Sep 28; [Epub ahead of print]

The immunosuppressant drug FTY720 inhibits cytosolic phospholipase A2 independently of sphingosine-1-phosphate receptors.

Payne SG, Oskeritzian CA, Griffiths R, Subramanian P, Barbour SE, Chalfant CE, Milstien S, Spiegel S.
Department of Biochemistry, Virginia Commonwealth University School of Medicine, Richmond, VA.

FTY720 is a potent immunomodulator drug that inhibits the egress of lymphocytes from secondary lymphoid tissues and thymus. FTY720 is phosphorylated in vivo by sphingosine kinase 2 to FTY720-phosphate, which acts as a potent sphingosine-1-phosphate (S1P) receptor agonist. However, in contrast to S1P, FTY720 has no effect on mast cell degranulation, yet significantly reduces antigen-induced secretion of PGD2 and cysteinyl-leukotriene. Unexpectedly, this effect of FTY720 was independent of its phosphorylation and S1P receptor functions. The rate-limiting step in the biosynthesis of all eicosanoids is the phospholipase A2 (PLA2)-mediated release of arachidonic acid from glycerol phospholipids.

Although FTY720 also reduced arachidonic acid release in response to antigen, it had no effect on translocation of cPLA2 or ERK1/2 activation, suggesting that it does not interfere with FceRI-mediated events leading to cPLA2 activation. Remarkably, however, FTY720 drastically inhibited recombinant cPLA2alpha activity, whereas FTY720-phosphate, sphingosine, or S1P had no effect.

This study has uncovered a unique action of FTY720 as an inhibitor of cPLA2alpha and hence on production of all eicosanoids. Our results have important implications for the potential therapeutic mechanism of action of FTY720 in eicosanoid-driven inflammatory disorders such as asthma and multiple sclerosis.

PMID: 17008548 [PubMed - as supplied by publisher]

http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_docsum

Learning about eicosanoids and fatty acids:

http://www.medical-library.net/sites...tty_acids.html