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| Edited By: |Source: ANI |Updated: May 23, 2011, 01:16 PM IST
A new study has found that a powerful pro-inflammatory protein, tumor necrosis factor (TNF), can also suppress aspects of inflammation.
Rheumatologists at Hospital for Special Surgery in New York said the identification of the mechanism of how this occurs could potentially lead to new treatments for diseases such as rheumatoid arthritis.
"Prior to this study, TNF has long been known as a potent pro-inflammatory cytokine, but if you look carefully through the literature, there are hints that it also has some suppressive functions, but nothing was known about the mechanisms," said Lionel Ivashkiv, lead author of the study.
"This is really the first mechanism showing how TNF can turn inflammation down," he said.
To come to the conclusion, researchers designed experiments stimulating macrophages with lipopolysaccharide (LPS), a prototypical inflammatory factor that stimulates receptors important in inflammation.
In test tube studies, the researchers treated human monocytes and macrophages, cells that have a key role in inflammatory diseases, with TNF and then challenged these cells with LPS.
They found that the TNF suppressed the inflammatory response of the macrophages and monocytes.
They then gave mice low doses of TNF followed by high doses of LPS and found that the mice were protected from the effects of high dose LPS, which is usually lethal.
They discovered that the mechanism by which TNF suppressed the inflammatory response involved a protein known as GSK3 (glycogen synthase kinase 3-alpha) and a gene known as TNFAIP3 that encodes the A20 protein.
The study was published May 22 online in advance of publication in the journal Nature Immunology.
