Among the first cells of the immune system to respond to microorganisms that invade our body are neutrophils. Although neutrophils are considered the "good guys" in such circumstances, they also contribute to the noninfectious chronic inflammation that underlies various diseases, including autoimmune diseases such as rheumatoid arthritis.
One mechanism by which neutrophils protect us is to internalize microorganisms and destroy them using proteins known as neutrophil serine proteases (NSPs), but whether NSPs have a role in noninfectious chronic inflammation has not been clearly determined.
However, using mice lacking two very similar NSPs, PR3 and NE, a team of researchers at the Max-Planck-Institute of Neurobiology, Germany, have now shown that these two NSPs have a crucial role in one form of noninfectious chronic inflammation. Detailed analysis revealed that PR3 and NE destroy an anti-inflammatory molecule known as PGRN and in this way help to promote inflammation in the absence of invading microorganisms.
The authors therefore suggest that these data provide rationale for considering inhibitors of NSPs as anti-inflammatory drugs.
- Kessenbrock et al. Proteinase 3 and neutrophil elastase enhance inflammation in mice by inactivating antiinflammatory progranulin. Journal of Clinical Investigation, 2008; DOI: 10.1172/JCI34694
Cite This Page: