Cleavage of Kininogen and Subsequent Bradykinin Release by the Complement Component: Mannose-Binding Lectin-Associated Serine Protease (MASP)-1

Abstract

Bradykinin (BK), generated from high-molecular-weight kininogen (HK) is the major mediator of swelling attacks in hereditary angioedema (HAE), a disease associated with C1-inhibitor deficiency. Plasma kallikrein, activated by factor XIIa, is responsible for most of HK cleavage. However other proteases, which activate during episodes of angioedema, might also contribute to BK production. The lectin pathway of the complement system activates after infection and oxidative stress on endothelial cells generating active serine proteases: MASP-1 and MASP-2. Our aim was to study whether activated MASPs are able to digest HK to release BK. Initially we were trying to find potential new substrates of MASP-1 in human plasma by differential gel electrophoresis, and we identified kininogen cleavage products by this proteomic approach. As a control, MASP-2 was included in the study in addition to MASP-1 and kallikrein. The proteolytic cleavage of HK by MASPs was followed by SDS-PAGE, and BK release was detected by HPLC. We showed that MASP-1 was able to cleave HK resulting in BK production. MASP-2 could also cleave HK but could not release BK. The cleavage pattern of MASPs is similar but not strictly identical to that of kallikrein. The catalytic efficiency of HK cleavage by a recombinant version of MASP-1 and MASP-2 was about 4.0×102 and 2.7×102 M−1s−1, respectively. C1-inhibitor, the major inhibitor of factor XIIa and kallikrein, also prevented the cleavage of HK by MASPs. In all, a new factor XII- and kallikrein-independent mechanism of bradykinin production by MASP-1 was demonstrated, which may contribute to the pro-inflammatory effect of the lectin pathway of complement and to the elevated bradykinin levels in HAE patients.

Serum MASP-1 in complex with MBL activates endothelial cells

“…Our results strengthen the view that MASP-1 plays a central role in the early innate immune response. After autoactivation it initiates the lectin pathway by activating MASP-2 and MASP-3, and it also has proinflammatory activity by cleaving other substrates, such as protease activated receptor, high molecular weight kininogen (Dobó et al, 2011) and fibrinogen (Gulla et al, 2009;Hess et al, 2012). In this way MASP-1 initiates a multi-faceted response against the possibly dangerous particles recognized by the pattern recognition molecules.…”

The Levels of the Lectin Pathway Serine Protease MASP-1 and Its Complex Formation with C1 Inhibitor Are Linked to the Severity of Hereditary Angioedema

“…It was shown previously that MASP-1 is able to cleave HMWK (14). We also addressed this using a solid-phase MBL/mannan set-up and both recombinant proteins (MBL and MASP-1) and MBL/MASP complexes purified from human plasma.…”

“…Recently, MASP-1 was shown to cleave HMWK into bradykinin (14); thus, we hypothesized that MASP-1 may be involved in pathophysiology of HAE. To investigate such a notion, we measured the serum concentration of MASP-1 and established ELISA-based methods to assess MASP-1/C1-INH complexes in serum samples from a cohort of 128 HAE patients during symptom-free periods, as well as 100 healthy matched controls.…”

Complement MASP-1 enhances adhesion between endothelial cells and neutrophils by up-regulating E‐selectin expression

“…However, we and other groups have described several other functions of MASP-1 beyond complement activation [6]. MASP-1 can cleave high-molecular-weight kininogen to bradykinin, a vasoactive and nociceptive peptide [7]. It can also cleave prothrombin, FXIII and TAFI, thus MASP-1 can modulate the function of the clotting and fibrinolytic systems [8][9][10].…”