Neutrophil-derived proteinase 3 induces kallikrein-independent release of a novel vasoactive kinin.
Författare
Summary, in English
The kinin-forming pathway is activated on endothelial cells and neutrophils when high-molecular weight kininogen (HK) is cleaved by plasma kallikrein liberating bradykinin, a potent mediator of inflammation. Kinins are released during inflammatory conditions such as vasculitis, associated with neutrophil influx around blood vessels. Some patients with vasculitis have elevated plasma levels of neutrophil-derived proteinase 3 (PR3) and anti-PR3 Abs. This study investigated if neutrophil-derived PR3 could induce activation of the kinin pathway. PR3 incubated with HK, or a synthetic peptide derived from HK, induced breakdown and release of a novel tridecapeptide termed PR3-kinin, NH(2)-MKRPPGFSPFRSS-COOH, consisting of bradykinin with two additional amino acids on each terminus. The reaction was specific and inhibited by anti-PR3 and alpha(1)-antitrypsin. Recombinant wild-type PR3 incubated with HK induced HK breakdown, whereas mutated PR3, lacking enzymatic activity, did not. PR3-kinin bound to and activated human kinin B(1) receptors, but did not bind to B(2) receptors, expressed by transfected HEK293 cells in vitro. In human plasma PR3-kinin was further processed to the B(2) receptor agonist bradykinin. PR3-kinin exerted a hypotensive effect in vivo through both B(1) and B(2) receptors as demonstrated using wild-type and B(1) overexpressing rats as well as wild-type and B(2) receptor knockout mice. Neutrophil extracts from vasculitis patients and healthy controls contained comparable amounts of PR3 and induced HK proteolysis, an effect that was abolished when PR3 was immunoadsorbed. Neutrophil-derived PR3 can proteolyze HK and liberate PR3-kinin, thereby initiating kallikrein-independent activation of the kinin pathway.
Avdelning/ar
Publiceringsår
2009
Språk
Engelska
Sidor
7906-7915
Publikation/Tidskrift/Serie
Journal of immunology
Volym
182
Issue
12
Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
American Association of Immunologists
Ämne
- Immunology in the medical area
Nyckelord
- Neutrophils: enzymology
- Myeloblastin: metabolism
- Myeloblastin: genetics
- Kinins: secretion
- Kininogens: metabolism
- Bradykinin: blood
- Kallikreins: metabolism
Status
Published
Forskningsgrupp
- Autoimmunity and kidney diseases
- Drug Target Discovery
- Internal Medicine - Epidemiology
- Pediatric Nephrology
ISBN/ISSN/Övrigt
- ISSN: 1550-6606