Daniel Elenius Madsen1, Johannes Jakobsen Sidelmann2, Daniel Biltoft2, Jørgen Gram2, Soren Hansen3. 1. University of Southern Denmark, Institute of Public Health, Unit for Thrombosis Research, Niels Bohrs Vej 9-10, 6700 Esbjerg, Denmark. Electronic address: daniel@elenius.eu. 2. University of Southern Denmark, Institute of Public Health, Unit for Thrombosis Research, Niels Bohrs Vej 9-10, 6700 Esbjerg, Denmark. 3. University of Southern Denmark, Institute of Molecular Medicine, Department of Cancer and Inflammation Research, J.B. Winsløws Vej 21, 5000 Odense C, Denmark.
Abstract
BACKGROUND: The FXII-dependent kallikrein-kinin system (KKS) is tightly regulated by the serine protease inhibitor (serpin) C1-inhibitor (C1-inh). When regulation of the FXII-dependent KKS fails, which is the case in hereditary angioedema (HAE), patients consequently experience invalidating edema attacks. HAE is caused by mutations in the C1-inh encoding gene, and we recently demonstrated that some mutations give rise to the presence of polymerized C1-inh in the plasma of HAE patients. METHODS: C1-inh polymers corresponding to the size of polymers observed in vivo were produced using heat denaturation and gel filtration. The ability of these polymers to facilitate FXII activation was assessed in vitro in an FXII activation bandshift assay. After spiking of plasma with C1-inh polymers, kallikrein generation was analyzed in a global kallikrein generation method. Prekallikrein consumption in the entire Danish HAE cohort was analyzed using an ELISA method. RESULTS: C1-inh polymers mediated FXII activation, and a dose dependent kallikrein generation in plasma spiked with C1-inh polymers. An increased (pre)kallikrein consumption was observed in plasma samples from HAE patients presenting with C1-inh polymers in vivo. CONCLUSION: Polymerization of the C1-inh transforms the major inhibitor of the FXII-dependent KKS, into a potent activator of the very same system. GENERAL SIGNIFICANCE: The C1-inh polymers might play a role in the pathophysiology of HAE, but several diseases are characterized by the presence of serpin polymers. The role of serpin polymers has so far remained elusive, but our results indicate that such polymers can play a role as inflammatory mediators through the FXII-dependent KKS.
BACKGROUND: The FXII-dependent kallikrein-kinin system (KKS) is tightly regulated by the serine protease inhibitor (serpin) C1-inhibitor (C1-inh). When regulation of the FXII-dependent KKS fails, which is the case in hereditary angioedema (HAE), patients consequently experience invalidating edema attacks. HAE is caused by mutations in the C1-inh encoding gene, and we recently demonstrated that some mutations give rise to the presence of polymerized C1-inh in the plasma of HAE patients. METHODS:C1-inhpolymers corresponding to the size of polymers observed in vivo were produced using heat denaturation and gel filtration. The ability of these polymers to facilitate FXII activation was assessed in vitro in an FXII activation bandshift assay. After spiking of plasma with C1-inhpolymers, kallikrein generation was analyzed in a global kallikrein generation method. Prekallikrein consumption in the entire Danish HAE cohort was analyzed using an ELISA method. RESULTS:C1-inhpolymers mediated FXII activation, and a dose dependent kallikrein generation in plasma spiked with C1-inhpolymers. An increased (pre)kallikrein consumption was observed in plasma samples from HAE patients presenting with C1-inhpolymers in vivo. CONCLUSION: Polymerization of the C1-inh transforms the major inhibitor of the FXII-dependent KKS, into a potent activator of the very same system. GENERAL SIGNIFICANCE: The C1-inhpolymers might play a role in the pathophysiology of HAE, but several diseases are characterized by the presence of serpin polymers. The role of serpin polymers has so far remained elusive, but our results indicate that such polymers can play a role as inflammatory mediators through the FXII-dependent KKS.
Authors: Ming Ming Yang; Jun Wang; Hong Ren; Yun Duan Sun; Jiao Jie Fan; Yan Teng; Yan Bo Li Journal: Mediators Inflamm Date: 2016-02-16 Impact factor: 4.711